Note: Descriptions are shown in the official language in which they were submitted.
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PEELABLE ADHESIVE TAPE AND ARTICLE-ATTACHING KIT
Background
This invention relates to an adhesive tape. More specifically, the invention
relates
to a peelable adhesive tape which after having been stuck to a material or
adherend can, as
required, be easily removed from the material without leaving any adhesive on
the
material, without giving any substantial damage to the material, and which can
further be
applied to any material inclusive of soft vinyl chloride, following up even
the material
having a rugged structure in the surface so as to be strongly adhered thereto.
The
invention further relates to an article-attaching kit having the adhesive
tape.
A variety of types of adhesive films and adhesive tabs or so-called adhesive
tapes
have been proposed and put into practical use to meet diversified objects. As
an adhesive
tape featuring peeling property, for example, there has, in recent years, been
put into
practical use an adhesive tape that can be stretched and removed without
damaging the
adhered material.
International Patent Publication (Kohyo) No. 6-504077 is disclosing an
adhesive
tape including a back lining and a pressure-sensitive adhesive carried on at
least one main
surface thereof, the back lining having a breaking elongation of 150% to 1200%
in the
lengthwise direction, an elastic recovery of smaller than 50% after stretched
and a Young's
modulus of at least 175.8 kg/cm2 (2500 psi) but smaller than 5097 kg/cm
(72,500 psi), the
tape being capable of strongly bonded to the base member (material referred to
in the
invention) and removed from the surface of the base member when pulled at an
angle of
not larger than 35 , and the back lining having a breaking tensile strength
large enough to
be not broken in removing the tape from the surface of the base member. This
adhesive
tape has already been put into practical use and is commercially available,
for example, as
COMMANDTM HOOK from 3M Co.
German Patent Laid-Open Publication No. 3331016 is disclosing a peelable
adhesive tape using a thermoplastic rubber such as a styrene/butadiene block
copolymer
and an adhesive-forming resin such as a rosin derivative as base materials,
the adhesive
tape having a high rubbery elasticity and a low plasticity, having an adhering
force which
is smaller than a cohesive force, having a holding force which suitably
decreases as the
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tape extends, having a ratio of the peeling strength to the tensile strength
of 1:2 or greater,
and the bonding of the adhesive produced by the tape being eliminated in the
direction of
the surface of adhesion as the adhesive tape is stretched. When applied to a
vinyl
chloride-type wall paper including a plasticizer, however, this adhesive tape
develops a
problem in that the plasticizer migrates into the adhesive of the tape causing
both the
adhering force and the cohesive force to decrease, and becomes no longer
usable.
There have further been proposed many adhesive tapes suited for sticking
together
the soft vinyl chloride films containing a plasticizer in large amounts.
Japanese Unexamined Patent Publication (Kokai) No. 5-302070) discloses an
ornamental film obtained by applying or laminating, on the film surface, an
adhesive agent
which contains 0.005 to 0.1 part by weight of a crosslinking agent per 100
parts by weight
of a copolymer having a weight average molecular weight of 700,000 to
1,200,000
obtained by copolymerizing 64 to 75% by weight of a (meth)acrylic acid ester
having a C4
to C8 alkyl group, 20 to 26% by weight of a methyl methacrylate and 5 to 10%
by weight
of an acrylic acid.
Japanese Unexamined Patent Publication (Kokai) No. 8-311414 discloses an
acrylic adhesive tape forming a multiplicity of adhesive layers, the exposed
adhesive layer
being an adhesive comprising chiefly a copolymer of 100 parts by weight of an
alkyl
(meth)acrylate ester monomer and i to 10 parts by weight of a nitrogen-
containing
(meth)acrylic monomer, and the adhesive layer continuous thereto being an
adhesive
comprising chiefly a copolymer of an alkyl (meth)acrylate ester. In the case
of this
adhesive tape, there has been reported that both the initial adhering force
and the cohesive
force exhibit sufficiently large values which in cooperation exhibit very
excellent adhering
performance without permitting the plasticizer to migrate into the vinyl
chloride resin and,
particularly, into the plasticized vinyl chloride resin. The present inventors
therefore have
used the adhesive proposed above for the pressure-sensitive adhesive of the
adhesive tape
disclosed in the above patent document 1. With the adhesive tape using the
above
adhesive, however, there occurs a problem in that when the adhesive tape is
peeled and
removed from the adhered material, the paste remains on the adhered material
due to
insufficient cohesive force of the adhesive and the adhered material is
damaged due to a
large adhering force.
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Summary
As described above, there have already been known a variety of types of
adhesive
tapes featuring pealing performance, some of them being commercially
available. To
meet diversified needs in recent years, however, it has been desired that the
peelable
adhesive tape can be adhered to any material or adherend, that when the
adhesive tape is
stuck to the material containing a plasticizer, the plasticizer does not
migrate to the
adhesive to deteriorate the cohesive force or the adhering force, that the
peeling =
performance is not adversely affected due to the loss of balance between the
cohesive
force and the adhering force, that the residue such as the adhesive does not
remain, and
that the adhesive tape can be strongly stuck to the material even when it has
a rugged
structure in surfaces thereof.
The present invention provides a peelable adhesive tape which, after stuck to
a
material, can be stretched so as to be easily removed entirely therefrom
through one time
of a pulling operation, leaves the adhesive little on the material, suppresses
damage to the
material, can be stuck to various materials inclusive of a soft vinyl
chloride, and can be
strongly adhered not only to a material having a flat surface but also to a
material having a
rugged structure in the surface thereof following up the shape to a sufficient
degree, as
well as to provide an article-attaching kit equipped with the adhesive tape.
According to the present invention, the above is achieved by a peelable
adhesive
tape used being stuck to a material or adherend, comprising a pair of:
a first adhesive element having a first adhesive layer directly applied to the
material; and
a second adhesive element, capable of being stretched, including a second
adhesive
layer applied to the material via the first adhesive layer and a base member
that supports
the second adhesive layer;
wherein the first adhesive layer has the strain and stress smaller than the
strain and
stress of the second adhesive element as measured by a tensile testing.
According to another aspect of the present invention, there is further
provided an
article-attaching kit for attaching an article to a material via an adhesive
layer, and having
a peelable adhesive tape of the invention in combination with an article that
is attached
and fixed to the material via the first and second adhesive layers of the
adhesive tape,
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wherein when the article is to be removed, as required, after it has been
attached, the
adhesive tape and the first and second adhesive layers are removed together
with the
article from the material.
As will be understood from the following detailed description, according to
the
present invention there can be provided a peelable adhesive tape which can be,
say,
"stretch-released", which, after having been stuck to a material, can be
removed therefrom
by being stretched. In particular, the adhesive agent of the invention can be
stuck to
various materials inclusive of a soft vinyl chloride, can be strongly adhered
not only to a
material having a flat surface but also to a material having a rugged
structure in the surface
thereof following up the shape to a sufficient degree, and can be easily
removed as a
whole from the material through one time of pulling operation leaving the
adhesive little
and suppressing damage to the adhered material.
The invention further provides an article-attaching kit equipped with the
adhesive
tape of the invention.
As described above, the present invention resides in:
(1) A peelable adhesive tape used being stuck to a material, which,
particularly, can be "stretch-released", comprising a pair of:
a first adhesive element having a first adhesive layer directly applied to the
material; and
a second adhesive element that can be stretched including a second adhesive
layer
applied to the material via the first adhesive layer and a base member (which
may be
omitted) that supports the second adhesive layer; and
(2) An article-attaching kit equipped with the adhesive tape of the invention.
The invention will now be described with reference to the accompanying
drawings.
Brief Descriution of Drawings
Fig. 1 is a sectional view illustrating a preferred embodiment of an adhesive
tape
according to the present invention.
Fig. 2 is a sectional view illustrating a preferred embodiment of a second
adhesive
element of the adhesive tape according to the present invention.
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Fig. 3 is a sectional view illustrating another preferred embodiment of the
second
adhesive element of the adhesive tape according to the present invention.
Figs. 4A-4C show sectional views illustrating a method of using the adhesive
tape
according to the present invention.
Fig. 5 is a sectional view illustrating a preferred embodiment of an adhesive
structure according to the present invention.
Fig. 6 is a perspective view illustrating a preferred embodiment of a material
set
according to the present invention.
Fig. 7 is a sectional view illustrating a method of testing the holding
performance
according to the embodiment.
Detailed Description
Fig. 1 is a sectional view illustrating a preferred embodiment of the adhesive
of the
present invention. As shown, a peelable adhesive tape 10 is constituted by a
pair of a first
adhesive element 10-1 having a first adhesive layer 3 directly applied to a
material or
adherend (not shown) and a second adhesive element 10-2. The second adhesive
element
10-2 has a stretchable base member I carrying on one surface thereof a second
adhesive
layer 2 of an adhesive composition. As will be described later, 4a, 4b and 14
denote
peeling papers which will be peeled off when the adhesive tape is to be used.
The base
member 1 is stretchable. Therefore, the adhesive tape 10 that is to be peeled
again from
the adhered material can be stretched to a suitable degree without adversely
affecting the
action and effect of the invention. The base member 1 in the illustrated
embodiment is a
single layer. As required, however, the base member 1 may of a multi-layer
structure of
two or more layers, and may be used as a composite base member or a laminated
base
member. The base member 1 has no second adhesive layer 2 at an end 1 a
thereof. This is
for efficiently conducting the pulling operation for stretching by using the
end 1 a as a tab.
As required, the second adhesive layer 2 may not be formed but, instead, a
separately
formed tab or the like piece of tape may be attached to the end of the base
member 1. In
the illustrated embodiment, the second adhesive layer 2 is applied to the one
surface only
of the base member 1. As will be described below, however, the second adhesive
layer 2
may be formed on both surfaces of the base member depending upon the use of
the
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adhesive tape. The base member having the adhesive layers applied on both
surfaces
thereof is suited for attaching any article to the material.
In the practice of the invention, as required, the base member may not be used
but,
instead, the surface of the second adhesive layer may be protected, and the
second
adhesive layer may be temporarily supported by protection means that can be
peeled off
the adhesive tape at the time of sticking the adhesive tape. Suitable
protection means is,
for example, a peeling paper described below as "peeling layer". If the
protection means
such as the peeling layer has a. suitable thickness and a strength, the
adhesive tape without
the base member can be attached in the same manner as the one having the base
member
and, besides, the thickness of the obtained adhered structure can be
decreased, and the gap
can be decreased between the article and the material to which the article is
attached.
In addition to using the two adhesive elements each having an adhesive layer
in a
pair, the adhesive tape of the present invention has a feature in that the
first adhesive layer
3 that is to be joined to the material exhibits a stress lower than the strain
and the stress of
the adhesive tape 10 as a whole when the strain and stress are measured by the
tensile test.
The first and second adhesive layers 3 and 2 may comprise the same adhesive
composition
or different adhesive compositions. From the standpoint of adjusting the
stress, however,
it is recommended to form the first and second adhesive layers 3 and 2 by
using different
adhesive compositions. It is further desired that the first and second
adhesive layers 3 and
2 have compositions and thickneses that can be stretched to meet the stretch
of the base
member. Details of the adhesive compositions will be described below.
Desirably, further, the first and second adhesive layers 3 and 2 can be
removed
together with the base member 1 when the adhesive tape 10 of the invention is
stretched
and peeled by being pulled at an angle of not larger than 35 from the surface
of the
adhered material.
In peeling the adhesive tape from the surface of the material while stretching
it,
further, it is desired that the adhering force that is measured is smaller
than the breaking
stress that is measured when the adhesive tape is subjected to the tensile
testing. More
desirably, the adhering force of when the adhesive tape is stretched and
peeled from the
surface of the material, is smaller than the breaking stress of when the
adhesive tape is
subjected to the tensile test and is 1/1.5 times thereof or smaller.
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In the adhesive tape 10 of the present invention, the surfaces where the
adhesive
layers are exposed of the adhesive elements, i.e., the adhesive surfaces of
the first adhesive
layer 3 and of the second adhesive layer 2 are protected by being covered with
peeling
papers called herein "peeling layers" (or often called release liners or
peeling liners) 14a,
14b and 4. The peeling papers are effective means for protecting the adhesive
surfaces as
well as for enhancing the preservability and handling of the adhesive tape.
The adhesive tape of Fig. 1 can be used in order shown in, for example, Fig.
4. In
Fig. 4, the second adhesive element 10-2 is the one obtained by applying the
adhesive
layers 2a and 2b onto both surfaces of the base member 1.
Referring, first, to Fig. 4(A), a material to be adhered is prepared. The
material
that is shown comprises, for example, a wall member 51 of an aluminum plate
and a wall
paper 52 of vinyl chloride having fine a rugged structure in the surface
thereof.
Referring next to Fig. 4(B), the peeling papers 14a and 14b are removed from
the
first adhesive element 10-1, and the first adhesive layer 3 is stuck to the
wall paper 52 of
the material. Immediately after the first adhesive layer 3 is stuck to the
wall paper 52 or
after a while, the second adhesive element 10-2 is larninated and stuck onto
the first
adhesive layer 3 on the wall paper 52.
The second adhesive element 10-2 may be stuck in a manner that it is stuck to
an
article 53 (hook for the wall paper, here) as shown in Fig 4(C), or the second
adhesive
element 10-2 only may be stuck. That is, the second adhesive element 10-2 is
stuck to the
article 53 via the third adhesive layer 2a and, then, the article 53 is pushed
onto the wall
paper 52 via the second adhesive layer 2b and is laminated thereon. Or, the
second
adhesive element 10-2 may be stuck to the wall paper 52 via the first adhesive
layer 3 and,
then, the article 53 may be stuck onto the third adhesive layer 2a.
The first adhesive layer 3 is, first, stuck onto the surface of the material
52. Even
when the surface of the material 52 is rugged, the first adhesive layer 3
follows the
ruggedness to accomplish a substantially wide adhering area. This further
enhances the
adhering force of the adhesive tape 10 as a whole to the material. The
operation for
sticking the adhesive tape can be carried out relying upon a technique that
has widely been
employed for sticking the adhesive tapes. As required, ajig may be used in
combination.
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Next, described below is the operation for removing the adhesive tape from the
adhered material. First, a tab 1 a at the end of the adhesive tape 10 is
nipped by fingertips
and is pulled with a suitable force in the direction of peeling. The angle for
pulling the
adhesive tape is, usually, not larger than about 35 degrees from the direction
substantially
in parallel with the surface of the adhesive tape. The angle for pulling the
adhesive tape is
desirably smaller than about 30 degrees and, more desirably, smaller than
about 10
degrees. In the initial step of pulling, the resistance is great, first, for
the shearing force of
the adhesive tape. The base member of the adhesive tape starts deforming when
a
sufficiently large force is applied to overcome the resistance. Accompanying
the
deformation of the base member, the adhesive layer starts stretching and is
directed. As a
result, the base member breaks down, the sectional area decreases and, hence,
is stiffened
in the direction of stretch. The stiffening effect, next, shifts the stress to
the interface
between the adhesive tape and the material, whereby the adhesive tape starts
peeling from
the material. The adhesive layer remains adhered on the adhesive tape that is
peeled, and
there is observed no adhesive that is left on the material. Further, the step
of peeling is not
substantially accompanied by the three-dimensional stress, and the adhesive
layers are not
transformed into filaments.
In the adhesive tape 10 of the embodiment of this invention, further, the
strain and
the stress of the first adhesive layer 3 as measured by the tensile testing
are lower than the
strain and stress of the adhesive tape 10. By pulling the tab l a of the
adhesive tape,
therefore, the first adhesive layer 3, the second adhesive layers 2a, 2b and
the base
member 1 can be peeled off integrally together at one time.
Here, the peeling of the highly stretched adhesive tape at a low angle is
characterized by the growth of cracks of a"sharp" type. As represented by the
fracture of
a vitreous material, sharp cracks work to highly concentrate the stress at the
ends of cracks
(where the stress extinguishes) of small volumes in the adhesive composition.
Due to a
high concentration of stress at the ends of the cracks, there occurs a so-
called brittle
cleavage fracture of the adhesive composition. Typically, this fracture occurs
accompanied by a small force (small amount of energy extinguishing in the
adhesive
composition) and obviously takes place on the interface.
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At larger peeling angles, i.e., when the angle is greater than 35 degrees, on
the
other hand, the base member of the adhesive tape does not stretch, and the
adhesive
composition turns into filaments thereof and is fractured cohesively. As
represented by
the fracture of a vitreous material, the growth of "blunt" cracks takes place
following the
crazing. In this model, filaments observed in the adhesive composition occur
as a
mechanism for extinguishing the energy like crazing fibrils seen in the
vitreous material.
Resistance against the peeling increases with an increase in energy that is
extinguished,
and an increased force is required for peeling the adhesive tape. As the
volume of the
material increases, the extinction of energy increases and the stress is not
so concentrated
as above. Therefore, the filaments of the adhesive composition are fractured
cohesively as
could not be avoided with the conventional technology, and the residue of the
adhesive
composition remains on the surface of the material. Otherwise, the surface of
the material
is damaged. Concerning the above feature, reference should be made to the
description of
International Patent Publication (Kohyo) No. 6-504077 (described above) if
necessary.
The adhesive tape of the present invention is not limited to the adhesive
tapes 10
shown in Figs. 1 and 4 only but can be varied and improved within the scope of
the
present invention such as omitting the base member, improving the base member
and
applying the adhesive layers to both surfaces. For example, the second
adhesive element
10-2 may have a base member I comprising two kinds of sheet-like support
members 11
and 12 as shown in Fig. 2. Here, the sheet-like support members 11 and 12 can
be
constituted by using various base members so far as they do not spoil the
action and effect
of the invention. For instance, the sheet-like support member 11 is
constituted by using a
foamed plastic film, and the sheet-like support member 12 integrally laminated
thereon is
constituted by using another kind of polymer film, e.g., non-foamed polymer
film (in other
words, solid polymer film). The second adhesive layer 2 is applied onto one
surface of the
base member I as shown. Further, a tab 1 a is formed at an end of the base
member 1.
Further, the second adhesive layer 2 is covered with a peeling paper which in
this
invention is called "peeling layer" (or is, often, called release liner or
peel liner) for
protection. The adhesive tape provided with the second adhesive element can be
advantageously used for attaching and fixing, onto a wall surface which is the
material to
be adhered, a sheet-like article such as a calendar, a poster, a film Or the
like. Further, the
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material to be adhered such as the wall surface is, usually, provided with the
adhesive tape
to constitute a structure to be adhered.
Fig. 3 illustrates an example in which the second adhesive element 10-2 is
constituted by a double-sided adhesive tape. As shown, the base member 1
includes a
sheet-like support member 11, and sheet-like support members 12a and 12b
integrally
laminated on both surfaces thereof. The sheet-like support members 12a and 12b
may or
may not have the same composition and the thickness. Further, the sheet-like
support
members 12a and 12b are, usually, constituted by using a material different
from that of
the sheet-like support member 11. For example, the sheet-like support member
11 is
constituted by a foamed polymer film, and both sides thereof are integrally
sandwiched
with the sheet-like support members 12a and 12b of solid polymer films. A
multi-layered
structure of four or more layers may be applied to the base member 1, as a
matter of
course. Adhesive layers 2a and 2b of a predetennined adhesive composition have
been
applied to both sides of the base member 1. Here, the adhesive layer 2b
corresponds to the
second adhesive layer referred to in the invention, and the adhesive layer 2a
corresponds
to the third adhesive layer referred to in the invention. A tab la is formed
at an end of the
base member 1. Further, the second adhesive layer 2b and the third adhesive
layer 2a are
covered with peeling papers 4b and 4a which, in this invention, are referred
to as the
"peeling layers" for protecting the adhesive surfaces. The adhesive tape
equipped with the
second adhesive element can be advantageously used for mounting an article
such as a
hook on the wall surface. The material such as the wall surface is, usually,
provided with
the adhesive tape to constitute a structure for adhesion.
Fig. 5 is a view schematically illustrating an example where the adhesive tape
equipped with the second adhesive element of Fig. 3 is stuck to the wall
paper, and an
article is attached to the wall paper. The wall paper 52 is made of a vinyl
chloride resin,
has a fine rugged structure in the surface thereof, and is stuck to a wall
member 51 of a
stainless steel. As described earlier with reference to Fig. 3, the adhesive
tape that is
shown has a second adhesive element of a base member 1 having surfaces facing
the third
adhesive layer 2a and the second adhesive layer 2b and, further, has a first
adhesive
element with the first adhesive layer 3. The adhesive tape completes the
structure 20 for
adhesion upon laminating the second adhesive element after the first adhesive
layer 3 has
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been stuck to the wall paper 52. Further, an article 53 is mounted on the wall
paper 52
(wall member 51) via the adhesive tape. The adhering force of the adhesive
tape is so
strong that the article 53 does not peel off the wall member 51.
To remove the article 53 from the wall member 51, the tab 1 a is pulled to
peel the
adhesive tape together with the article 53 off the wall paper 52 in a manner
as described
above. According to the present invention, the second adhesive layer 2b and
the first
adhesive layer 3 are so combined together as to satisfy a particular
relationship of stress.
Therefore, the adhesive tape that is strongly bonded to the wall paper 52 can
be easily
peeled off by being pulled with a weak force without leaving the adhesive on
the wall
paper 52.
As described above, the peelable adhesive tape of the present invention
includes
the pair of the first and second adhesive elements as constituent elements
and, further,
includes a substitute for the base material, a third adhesive layer and a
peeling layer as
constituent elements. These constituent elements will now be concretely
described.
The adhesive tape of the present invention may not often use the base member
depending upon the cases, but generally uses, as a main member, a stretchable
base
material or, on other words, a base member which can be stretched at a
predetermined
stretching ratio when it is pulled in the lengthwise direction thereof. The
base member
used for producing the adhesive tape is, preferably, a highly stretchable
polymer film.
Here, "highly stretchable" stands for a property which produces the stretching
of at least
about 150% on the basis of the initial length when the adhesive tape (base
member) is
stretched in the lengthwise direction. The base member used in the embodiment
of the
present invention can be varied depending upon the use of the adhesive tape
but, usually,
produces the stretching of about 50 to about 1,200%. When the stretching ratio
of the base
member is smaller than 50%, the stretch-release effect of the invention is no
longer
obtained. Conversely, when the stretching ratio of the base member exceeds
1,200%, it
becomes difficult to peel the adhesive tape off the material at a good timing.
The base
member is capable of producing the stretching which is, desirably, about 150
to about
700% and, more preferably, about 350 to about 700%.
The highly stretchable polymer film that can be used as the base member
includes
various polymer films, and, desirably, includes the below-mentioned polymer
films (1) to
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(4) in one kind or in any combination of two or more kinds, as the base member
of the
tape.
(1) A polymer film having a breaking elongation of about 50 to about 1,200%
in the lengthwise direction, an elasticity recovery of smaller than about 50%
after
stretched and a Young's modulus of about 1,000 to about 72,500 psi (i.e.,
about 6,894.7 to
499,865.8 KPa)(first polymer film);
(2) A foamed polymer film (second polymer film);
(3) A polymer film having an yield stress or a proportional critical stress of
not
larger than about 20 N/15 mm, a tensile breaking strength of not smaller than
about 30
N/15 mm, and a breaking elongation of not smaller than about 150% (third
polymer film);
and
(4) A polymer film containing a thermoplastic rubber and an adhesive-forming
resin (fourth polymer film).
When these or other polymer films are used in a combination of two or more
kinds,
it is desired that the polymer films as a whole are used being integrally
bonded together in
the form of a composite film or a laminated film. There is no particular
limitation on the
method of integrating the polymer films, and there can' be exemplified a
simultaneous
forming, a junction with an adhesive and a junction by pressing.
If described in further detail, the polymer films (1) to (4) are as described
below.
The compositions and constitutions of the polymer films can be applied to
other polymer
films, too, unless stated otherwise.
The first polymer film is a highly stretchable polymer film having a breaking
elongation in the lengthwise direction of about 50 to about 1,200%,
preferably, about 150
to 700% and, more preferably, about 350 to 700%, an elasticity recovery after
stretched of
smaller than about 50%, preferably, smaller than about 30% and, more
preferably, smaller
than about 20%, and a Young's modulus of at least about 1,000 psi (about
6,894.7 KPa),
preferably, about 2,500 psi (about 17,236.8 KPa) and, more preferably, at
least about
3,000 psi (about 20,684.1 KPa) but not larger than about 72,500 psi (about
499,865.8
KPa), preferably, not larger than about 50,000 psi (about 344,753 KPa) and,
more
preferably, about 5,000 to about 30,000 psi (about 34,473.5 to about 206,841
KPa). When
the polymer film has a too high Young's modulus, it becomes very difficult to
stretch the
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adhesive tape to a degree large enough for accomplishing a smart peeling. When
the
Young's modulus is too low, the adhesive tape loses the plasticity and becomes
rubbery.
The breaking elongation of the base member must be so high that the base
member is not
broken before the tape is removed from the surface of the material to which
the adhesive
tape has been adhered. The breaking elongation of the base member is,
preferably, at least
about 4,000 psi (about 27,578.8 KPa), more preferably, at least about 5,300
psi (about
36,541.9 KPa) and, most preferably, at least about 6,300 psi (about 43,436.6
KPa).
Though not limited thereto only, representative examples of the material that
can
be preferably used for the polymer film include polyolefins such as
polyethylene, high-
density polyethylene, low-density polyethylene, linear low-density
polyethylene, linear
ultra-low-density polyethylene, polypropylene and polybutylene; vinyl
copolymers such as
polyvinyl chloride (including both of those that have been plasticized and
those that have
not been plasticized) and polyvinyl acetate; olefinic copolymers such as
ethylene/methacrylate copolymer, ethylene/vinyl acetate copolymer,
acrylonitrilefbutadiene/styrene copolymer and ethylene/propylene copolymer;
acrylic
polymer and copolymer; and mixtures thereof. There can be further arbitrarily
used
plastic or plastic and elastic materials, such as polypropylene/polyethylene,
polyurethane/polyolefin, polyurethane/polycarbonate, polyurethane/polyester,
and the like.
These polymer films can be a single-layer or a multi-layer film, a non-woven
film, a
porous film, or a foamed film, or a combination thereof. The polymer film may,
further,
be made of a filler-containing material, i.e., may be a filler-containing
film, such as the
one made of a polyolefin containing calcium carbonate. The polymer film is,
preferably,
selected from polyethylene and polypropylene films, and the most desired
material is
linear low-density and ultra-low-density polyethylene film's.
The above polymer can be produced by any known film-forming method, such as
extrusion method, simultaneous extrusion method, solvent casting method,
foaming
method or felt-forming method.
The polymer film may have any thickness so far as it has a uniting property
large
enough for accomplishing the machining and handling and, preferably, has a
thickness in a
range of about 10 to about 250 m. The polymer film having a thickness of not
larger
than 10 m may not be capable of preventing the adhesive composition that is
used from
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oozing out in case the adhesive composition has a property to ooze out, and is
not
desirable. Conversely, when the thickness of the polymer film exceeds 250 m,
a
stretching force higher than a desired force is, usually, required for peeling
and removing
the adhesive tape from the material, i.e., the removal becomes difficult. When
the
thickness lies within a preferred range, there exists a tendency that a thin
polymer film can
be removed more easily than the thick ones. Concerning the first polymer film,
reference
should be made to International Patent Publication No. 6-504077 (described
earlier), if
necessary.
The second polymer film is a foamed polymer film or, in other words, a layer
or a
film of polymer foam. Though not limited thereto only, representative examples
of the
foamed polymer film include polyolefins such as high-density polyethylene, low-
density
polyethylene, linear low-density polyethylene and linear ultra-low-density
polyethylene;
vinyl copolymers such as polyvinyl chloride (including both of those that have
been
plasticized and those that have not been plasticized) and polyvinyl acetate;
olefinic
copolymers such as ethylene/methacrylate copolymer, ethylene/vinyl acetate
copolymer,
acrylonitrile/butadiene/styrene copolymer and ethylene/propylene copolymer;
acrylic
polymer and acrylic copolymer; polyurethane; and combinations thereof. There
can be
used any plastic material or a mixture or a blend of plastic and elastomeric
materials, such
as polypropylene/polyethylene, polyurethane/polyolefin,
polyurethane/polycarbonate, and
polyurethane/polyester.
The foamed polymer film, usually, has a density of about 2 to about 301b./ft3
(about 32 to about 481 kg/tn3). When lying within this density range, the foam
of the
polymer film is stretched, and the adhesive tape can be favorably peeled off
the material.
Particularly preferred foamed polymer films are polyolefinic foamed films.
Among such foamed polymer films, the most preferred ones are the polyolefin
foams,
trade names "Volextra (trademark)" and "Volara (trademark)" manufactured by
Sekisui
(U.S.A.) Co., Voltek Department, Massachusetts, U.S.A.
As required, there may be used a non-foaming film, i.e., a solid polymer film
together with the foamed polymer film or, in a particular case, in its place.
The above
3 0 polymer film is desirably selected from polyethylene and polypropylene
films. The most
desired materials are linear low-density polyethylene film and linear ultra-
low-density
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polyethylene film. A preferred polyethylene film is the one having a trade
name
"Maxilene (trademark) 200" manufactured by Consolidated Thermoplastics Co.,
Illinois,
U.S.A.
The foamed polymer film may have any thickness so far as it can be worked and
handled to a sufficient degree and that it imparts desired performance related
to tensile
properties for peeling the adhesive tape off the material. This thickness is,
usually, in a
range of about 10 to about 250 m and, preferably, in a range of about 10 to
about 150
m. Concerning the second polymer film, reference should be made to
International
Patent Publication No. 9-502213, if necessary.
The third polymer film is the one having a yield stress or a proportional
critical
stress of not larger than about 20 N/15 mm, a tensile breaking strength of not
smaller than
about 30 N/15 mm, and a breaking elongation of not smaller than about 150%.
This
polymer film is thin and has a high modulus of elasticity yet capable of being
stretched to
a sufficient degree with a low yielding force. When used as the base member of
the tape,
therefore, the adhesive tape can be peeled off without developing curls. The
polymer film
features the following properties: i.e., an yield stress or a proportional
critical stress of not
larger than about 20 Nf 15 mm irrespective of the thickness, a tensile
breaking strength
(breaking strength) of not smaller than about 30 N/15 mm at any thickness, and
a breaking
elongation (stretchability) in the lengthwise direction of not smaller than
about 150% and,
particularly, about 150 to about 1,500%.
In this polymer film, the modulus of elasticity thereof represents a stress in
a
portion of the base member that is stretched first. The stress that
substantially
accompanies the peeling by pulling is the sum of the yield stress or the
proportional
critical stress of the base member and the adhering force that is dependent
upon the angle
of pulling. By using a material having a sufficiently low yielding point or a
proportional
critical point, though it may have a high Young's modulus, in combination with
a suitable
adhesive composition, it is made possible to provide an adhesive tape having a
tensile
force that meets the user's demand. Besides, the material having a high
Young's modulus
also exhibits rigidity, and can be easily handled by the user.
It is further desired that the polymer film exhibits an elasticity recovery
after
stretched of not larger than 50%. That is, in the case of the adhesive of the
present
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invention, it is desired that the base member that is used loses the
elasticity after it is
stretched once by being pulled and peeled. By using the above polymer film
which is
highly stretchable and having a high breaking strength as a base member for
producing the
adhesive tape, there is obtained the adhesive tape which can be easily
stretched when it is
to be stretch-released without damaging the surface that is being adhered and
without
substantially leaving the adhesive after the adhesive tape has been released.
Though not limited thereto only, examples of the polymer that can be
advantageously used for forming the polymer film include polyolefins such as
high-
density polyethylene HDPE), low-density polyethylene LDPE), linear low-density
'
polyethylene (LLDPE), linear ultra-low-density polyethylene U-LLDPE) and
polypropylene (PP); polyvinyl polymers such as polyvinyl chloride (PVC) and
polyvinyl
acetate (PVA); polyolefinic copolymers such as ethylene/methacrylic acid
copolymer
(EEMA), ethylene/vinyl acetate copolymer EVA); block copolymers such as
acrylic
polymer and styrene/isoprene/vinyl acetate copolymer; and various
thermoplastic
elastomers (TPE) such as polyolefins. The polymer film may be made from any
one of
these polymers or a mixture of two or more of these polymers.
The polymer film may be a single layer of the above polymer film or may be a
composite film formed by integrally laminating two or more pieces of polymer
films. In
the latter case, the above polymer film may be included in at least any one of
the layers of
the composite film. In the case of the polymer film used in this invention,
however, it is
desired that the tensile strain is not larger than 10% relative to the
specified stress of 2
MPa. This is effective in preventing the adhesive tape that is finished as a
thin film from
curling that is caused by the bending stress produced by its own back surface
(when it is in
a rolled state) or when it is taken out from the peeling paper.
The above-mentioned polymer films can assume various forms. Suitable films
may be, for example, a film of a non-woven fabric, a film of a woven fabric, a
porous film
and a foamed film. As required, films of different kinds may be used in
combination as a
single polymer film.
The thickness of the polymer film can be varied over a wide range depending
upon
the use but is, usually, in a range of about 10 to about 250 m and, more
preferably, in a
range of about 30 to about 100 m. When the thickness is smaller than 10 m,
the
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polymer film can no longer maintain a sufficient degree of tensile strength,
and can no
longer work as a base member for the adhesive tape. When the thickness exceeds
250 m,
on the other hand, the operation becomes substantially difficult to peel the
adhesive tape
off the material due to a high tensile strength, and the effect of forming the
adhesive tape
in a decreased thickness is lost.
The above polymer film can be produced by using a technique that has generally
been employed for producing the polymer films. In the case of the polymer film
of, for
example, a composite structure, the starting polymers are simultaneously
extruded from
suitable dies, and are stretched to form the first and second polymer films.
Further, the
polymer films that have been formed in advance may be laminated and melt-
adhered
together. Depending upon the cases, the polymer films may be joined together
by using an
adhesive. Concerning the third polymer film, reference should be made to
Japanese
Unexamined Patent Publication No. 2002-167558, if necessary.
The fourth polymer film is the one containing a thermoplastic rubber and an
adhesive-forming resin, i.e., a rubber/resin polymer film. Here, the rubber
component is
the one that has not been vulcanized and that imparts the required rubbery
elasticity and
cohesive force to the polymer film. As the thermoplastic rubber, there can be
used, for
example, a styrene/butadiene block copolymer and a styrene/isoprene block
copolymer.
On the other hand, the resin component is for realizing excellent adhesiveness
to various
materials. As the adhesive-forming resin, there can be used, for example, a
natural or
synthetic resin existing as an ester or a free acid, such as rosin derivative,
terpene resin,
terpene-phenol resin and synthetic petroleum resin. These resins may be
hydrogenated,
disproportionated or dimerized.
As required, the polymer film contains additives that have been generally used
in
the field of polymer films, such as antioxidant, ultraviolet ray stabilizer,
coloring agent,
etc.
The thickness of the polymer film can be varied over a wide range but is,
generally, in a range of about 200 to about 600 m.
The polymer film can be produced according to various methods. Usually,
however, the polymer film is produced by dissolving the above-mentioned rubber
component and the resin component in a solvent such as benzene, and applying
the
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obtained highly concentrated solution onto a peeling paper or the like by
using an
applicator, followed by drying. As a simplified method, there can be
exemplified the one
in which a starting mixture is heated and blended, and is flow-stretched or
extrusion-
molded at a temperature of about 120 to about 160 C.
Concerning the fourth polymer film, reference should be made to German Laid-
Open
Patent Publication No. 3331016 (described above), if necessary.
The above-mentioned polymer films and other polymer films useful as the base
member in the embodiment of the present invention can be varied and improved
within the
scope of the present invention. For example, the polymer film may, as
required, contain
an organic or inorganic filler dispersed therein. As the organic filler, there
can be
exemplified a resin material different from the polymer constituting the
polymer film. As
the inorganic filler, further, there can be exemplified calcium carbonate,
titanium oxide
and silica. Such fillers are useful for further enhancing the rigidity of the
film or for
lowering the yield point to suppress the tensile force of the film.
The organic or inorganic filler contained in the polymer film can possess
various
forms and sizes, preferably, such as spherical particles, needle-like crystals
or like forms.
The sizes thereof can be widely varied but are, usually, in a range of about 1
to about 20
m. In the case of needle-like whiskers, for example, it is desired that the
sizes are
relatively fine, the length thereof being, preferably, in a range of about I
to about 15 m
and, more preferably, about 10 m. The needle-like whiskers have a diameter
of, usually,
about 0.1 m. When the size of the filler used here is not larger than I m,
the filler must
be used in large amounts to obtain the effect of adding the filler. When the
size exceeds
20 m, on the other hand, formation of the film and other desired effects are
adversely
affected.
The above-mentioned filler can be contained in the polymer film in amounts
over a
wide range but is, usually, added in an amount over a range of, desirably,
about 5 to about
50% by weight. When the filler is added in an amount smaller than 5 ;'o by
weight, the
effect of addition is not exhibited. Conversely, when the amount of addition
exceeds 50%
by Nveight, formation of the film and other desired effect may be adversely
affected.
Usually, it is desired that the filler is added in an amount of about 10% by
weight.
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As required, further, the polymer film may be tinted in any color. Being
tinted, the
adhesive tape that is finally obtained exhibits improved appearance and
handling. The
tinted color may be a monotone or a combination of two or more kinds of colors
for
improving the design. Further, when the base member has a multi-layer
structure, one or
more pieces of polymer films constituting the base member may be arbitrarily
tinted.
When the use as the base member of the adhesive tape is not adversely affected
and when the additional action and effect can be expected, the polymer film
may further
incorporate other additional layers such as reinforcing layer, cushioning
layer and parting
layer that have been incorporated, as required, in the field of adhesive
tapes.
The base member of the adhesive tape may be a single layer of the above-
mentioned polymer film or any other suitable polymer film, or may be a multi-
layer
structure or a composite structure of two or more layers. When used as the
multi-layer
structure, the polymer films of the same kind may be laminated or the polymer
films of
two or more kinds may be laminated in any combination. In either of these
cases, the
polymer films may be laminated on the surfaces of the multi-layer structure
obtained by
using materials of kinds different from the base member referred to in the
invention, or
may be inserted therein.
The base member can be used in any thickness depending upon the constitution
and use of the adhesive tape but, usually, has a thickness in a range of about
10 m to
about 30 mm. When the thickness is smaller than 10 m, the base member becomes
too
thin, and it becomes difficult to produce the adhesive tape and, besides,
handling of the
adhesive tape itself is deteriorated. Conversely, when the thickness of the
base member is
not smaller than 30 mm, the obtained adhesive tape becomes too thick,
deteriorating the
handling, increasing the cost of production, and limiting the use. Desirably,
the base
member has a thickness over a range of about 10 m to about 10 mm.
The base member may be directly used or may further have an auxiliary adhesive
layer on one surface thereof or on both surfaces thereof. That is, when the
base member
consists of a polymer film, it is desired that one surface or both surfaces of
the polymer
film are provided with an auxiliary adhesive layers of an adhesive of the type
same as, or
different from, the adhesive composition constituting the adhesive tape. Upon
forming the
auxiliary sticking layer on one or both surfaces of the base member, it is
allowed to further
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enhance the effect of junction of the adhesive layer and the effect of
preventing the
adhesive from being left on the material and of preventing the occurrence of
damage.
The base member may be provided with the auxiliary adhesive layer or the
adhesive layer without at all treating the surfaces thereof. To enhance the
effect of
adhesion between the two, however, it is desired to effect the primer
treatment in advance.
As the primer treatment, there can be exemplified a corona discharge
treatment, a plasma
discharge treatment, a flame treatment, an electron beam irradiation, an
ultraviolet ray
irradiation and a primer coating.
The adhesive tape of the invention includes at least two adhesive layers,
i.e., the
first and second adhesive layers in combination with the above-mentioned base
member or
in the absence of the base member. These adhesive layers may comprise the same
adhesive composition or different adhesive compositions. These adhesive layers
are,
usually, used on one surface of the base member. As required, however, an
additional
adhesive layer or a third adhesive layer may be provided on the surface on the
opposite
side of the base member. The first and second adhesive layers are used for
sticking the
adhesive tape onto the material, and the third sticking layer is used for
attaching any
article onto the material via the sticking layer.
The first adhesive layer, second adhesive layer, third adhesive layer and any
other
adhesive layer provided as required, can be formed by using various adhesive
compositions suited for the adhesive layers. For instance, a first component
having
cohesive force (cohesive component) and a second component (basic component)
can be
used alone or in combination. In particular, it is advantageous to use the
adhesive
composition containing at least a mixture of two kinds of these components.
The
individual components will be described hereinbelow.
(1) First component.
The first component is a cohesive component. It is desired that the cohesive
component contains a styrene-type block copolymer as a main component. The
styrene-
type block copolymer useful for putting the invention into practice may
include a
3 0 styrene/isoprene block copolymer, a styrene/butadiene block copolymer, a
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styrene/ethylene/propylene block copolymer, and a styrene/ethylene/butylene
block
copolymer.
The cohesive component can contain an adhesion-imparting agent in addition to
the above-mentioned styrene-type block copolymer. Though not limited thereto
only,
suitable examples of the adhesion-imparting agent include a rosin resin, a
rosin ester resin,
a hydrogenated rosin ester resin, a terpene resin, a terpene phenol resin, a
hydrogenated
terpene resin, a petroleum resin, a hydrogenated petroleum resin, a chroman
resin, a
styrene resin, a modified styrene resin, a xylene resin and an epoxy resin.
As required, further, the first component can contain other additives.
Suitable
examples of the additives include a softening agent, an anti-aging agent, an
ultraviolet ray
absorber and the like. Examples of the softening agent include those agents of
the paraffin
type, naphthene type and phthalic ester type. As the anti-aging agent, there
can be used
anti-oxidants of the hindered phenol type or the hindered amine type.
(2) Second component.
The second component is a basic component. The basic component contains, as a
chief component, a (meth)acrylic copolymer and, preferably, a nitrogen-
containing
(meth)acrylic copolymer. The nitrogen-containing (meth)acrylic copolymer can
include
copolymers of various types and is, desirably, a copolymer of a (meth)acrylic
acid alkyl
ester and a nitrogen-containing vinyl monomer.
The copolymer of the (meth)acrylic acid alkyl ester and the nitrogen-
containing
vinyl monomer can be prepared by copolymerizing the alkyl (meth)acrylate ester
and the
nitrogen-containing vinyl monomer at various mixing ratios. The copolymer,
preferably,
comprises about 45 to about 99.9 parts by weight of the alkyl (meth)acrylate
ester and 0.1
to 20 parts by weight of the nitrogen-containing vinyl monomer. As required,
further, the
nitrogen-containing (meth)acrylic copolymer may be grafted with a polystyrene
having a
glass transition point of about 20 to 250 C and a weight average molecular
weight of
about 2,000 to 500,000 as measured by a gel permeation chromatography (GPC) in
an
amount of 0 to about 30 parts by weight. This is because, the solution of the
mixed
3 0 adhesive composition does not easily separate into upper and lower two
layers in the
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molten state. As required, fiu-ther, a vinyl monomer having a reactive
functional group on
a side chain may be copolymerized in an amount of about 0.1 to 5 parts by
weight.
If concretely described, the alkyl (meth)acrylate ester that can be used for
preparing the nitrogen-containing (meth)acrylic copolymer is, preferably, a
(meth)acryic
acid ester having an alkyl group with about 1 to about 11 carbon atoms. Though
not
limited thereto only, representative examples of the (meth)acrylic acid ester
include
methyl (meth)acrylate ester, ethyl (meth)acrylate ester, butyl (meth)acrylate
ester, 2-
methylbutyl (meth)acrylate ester, t-butyl (meth)acrylate ester, 2-ethylhexyl
(meth)acrylate
ester, isooctyl (meth)acrylate ester, cyclohexyl (meth)acrylate ester, and
isoboronyl
(meth)acrylate ester. These (meth)acrylic acid esters may be used alone or in
a
combination of two or more kinds.
The nitrogen-containing vinyl monomer is, preferably, a vinyl monomer having
an
amido group or a tertiary amino group. Though not limited thereto only,
representative
examples of the nitrogen-containing vinyl monomer include N,N-
dirnethylacrylamide, N-
isopropylacrylamide, N,N-dimethylaminoethyl(meth)acrylate; N,N-
dimethylaminopropylacrylamide, 2-vinylpyridine, 4-vinylpyridine and 1-
vinylimidazole.
These nitrogen-containing vinyl monomers may be used alone or in a combination
of two
or more kinds.
The above nitrogen-containing vinyl monomer can be copolymerized at various
ratios when being copolymerized with the alkyl (meth)acrylate ester but,
usually, at a ratio
of, preferably, about 0.1 to about 20 parts by weight. This is because, when
the ratio of
the vinyl monomer is smaller than 0.1 part by weight, the adhering force may
become
insufficient for the soft vinyl chloride which is the material to be adhered.
When the ratio
thereof exceeds 20 parts by weight, on the other hand, a (meth)acrylate-type
copolymer of
a low molecular weight may be formed in the copolymerization of the second
component.
In producing the nitrogen-containing (meth)acrylic copolymer according to the
present invention, the (meth)acrylic copolymer can be grafted with the
polystyrene. As a
simple method of grafting, there can be exemplified a method of copolymerizing
a styrene
macromer. Details of the method of synthesizing the styrene macromer have been
disclosed in Japanese Unexamined Patent Publication No. 59-75975 and are not
described
here. Further, the styrene macromer is commercially available as "MACROMONOMER-
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AS-6S" (trade name) from Toa Gosei Co. It is allowable to graft the
polystyrene relying
upon a method other than the above method, as a matter of course.
In preparing the nitrogen-containing (meth)acrylic copolymer, there is used a
vinyl
monomer having a reactive functional group on a side chain thereof. Though not
limited
thereto only, the vinyl monomer that can be used may be carboxyl group-
containing vinyl
monomers or acid anhydrides thereof, such as acrylic acid, methacrylic acid,
itaconic acid
and maleic acid, and hydroxyl group-containing vinyl monomers such as 2-
hydroxyethyl
acrylate and 2-hydroxyethyl methacrylate. The vinyl monomer having a polar
group such
as carboxyl group or hydroxyl group and the vinyl monomer having a photo-
reacting
group, such as acryloylbenzophenone, may impart a crosslinking reaction point
to the
(meth)acrylic resin composition.
Further, the crosslinking reaction may be induced with the crosslinking
reaction
point as a start point by using a crosslinking agent in combination. As the
crosslinking
agent, there can be used the one that is usually used in the chemistry of
polymerization,
such as polyfunctional epoxy compound, polyfunctional melamine compound,
polyfunctional isocyanate compound, metallic crosslinking agent and
polyfunctional
aziridine compound. Or, the crosslinking reaction may be induced by using
radiant rays
such as UV and EB without using crosslinking agent.
In the adhesive composition used in forming the adhesive layer, the above
first and
2 0 second components can be mixed at various ratios, and there is no
particular limitation on
the mixing ratio. The mixing ratio of the first component and the second
component is,
usually, in a range of about 5:95 to about 95:5 (solid component ratio) and,
preferably, in a
range of about 25:75 to about 90:10. When the mixing ratio of the two
components is
within the above range, there is no problem such as the adhesive is left on
the material or
the material is damaged due to a large adhering force stemming from a very
large cohesive
force of the adhesive at the time when the adhesive tape is peeled and removed
from the
material. Even when the adhesive structure of the present invention is
produced by
sticking the adhesive tape onto a vinyl chloride-type sheet or a wall paper
containing a
plasticizer, it does not happen that the plasticizer migrates into the
adhesive layer to
greatly deteriorate the cohesive force or the adhering force of the adhesive
tape.
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The second adhesive layer may be applied onto only one surface of the base
member of the adhesive or onto both surfaces of the base member of the tape as
second
and third adhesive layers depending upon the use and constitution of the
adhesive tape. In
either case, the thickness of the adhesive layer can be varied over a wide
range depending
upon the use or constitution of the adhesive tape. The thickness of the
adhesive layer is
usually in a range of about 10 to about 1,000 m, preferably, in a range of
about 10 to
about 400 m and, more preferably, in a range of about 10 to about 200 m. In
this
preferred range of thickness, a thick layer enables the adhesive tape to be
easily removed
as compared to a thin layer. This is symmetrical to an ordinary method of
removing, such
as a method of removing at a peeling angle of, for example, not smaller than
90 degrees.
In general, a thick layer before being adhered tends to exhibit a large
peeling force at a
peeling angle of the adhesive tape of 180 degrees as compared to a thin layer.
When the
adhesive tape of the present invention is removed by stretching at a low angle
of smaller
than 35 degrees, the adhesive composition tends to be locked by the base
member of the
tape and is forced to stretch significantly. Under these conditions, the
adhesive layer
(individual adhesive layers when there are many) undergoes the contraction to
decrease
the sectional area thereof. The sectional area of a thin adhesive layer, i.e.,
thickness x
width, is smaller than that of a thick adhesive layer. Therefore, the stress
or the force per a
unit area becomes greater in a thin layer than in a thick layer. In practice,
this makes the
adhesive composition rigid. A layer having a large rigidity exhibits a high
resistance
against the deformation and, hence, a large force is needed for the peeling.
The adhesive tape typically uses a first adhesive layer of an adhesive
composition
different from the adhesive layer thereof in combination with the second
adhesive layer of
the second adhesive element. The first adhesive layer constitutes the first
adhesive
element and is, preferably, formed by using a rubber-type adhesive, an acrylic
adhesive or
a mixture thereof like the second adhesive layer (for details, see the above
description
related to the second adhesive layer). As required, further, these adhesive
agents contain
an adhesion-imparting agent and any other additives (see the description
above). Though
not limited thereto only, examples of the adhesive include rubber-type
adhesives such as
natural rubber, olefin polymer, silicone polymer, isoprene, polybutadiene,
polyurethane,
styrene/isoprene/styrene copolymer and styrene/butadiene block copolymer, and
acrylic
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adhesives such as a copolymer of an acrylic acid ester of an alkyl with 4 to
16 carbon
atoms and an acrylic acid, etc.
As described above, the first adhesive layer can be formed relying upon the
same
method as the one for forming the second adhesive layer and using the same
adhesive
composition. As a preferred example, when the material to be adhered is a wall
paper of
vinyl chloride, the adhesive composition is, advantageously, a mixture of (i)
a resin
composition using a styrene-type block copolymer as a chief member and (ii) a
nitrogen-
containing (meth)acrylic copolymer obtained by copolymerizing an alkyl
(meth)acrylate
ester or a derivative thereof with a nitrogen-containing vinyl monomer. Though
there is
no particular limitation, the mixing ratio of the components (i) and (ii) is,
usually, in a
range of (i):(ii) = 5:95 to 95:5 (solid component ratio) and, preferably, in a
range of 25:75
to 90:10.
When the first adhesive layer is measured for its strain and stress by the
tensile test
as described above, it is desired that the strain and=stress that are measured
are lower than
a strain-stress curve by the tensile test of the second adhesive element
having the second
adhesive layer that is to be laminated on the first adhesive layer. This is
because, when the
tensile stress of the first adhesive layer is greater than that of the
adhesive tape, the first
adhesive layer cannot be simultaneously peeled off at the time when the
adhesive tape is
peeled off the material, and the first adhesive layer remains on the surface
of the material
after the adhesive tape is peeled off.
The thickness of the first adhesive layer can be varied over a wide range
depending
upon the use and constitution of the adhesive tape. The thickness of the
adhesive layer is,
usually, in a range of about 25 to about 3,000 m, preferably, in a range of
about 25 to
about 400 m and, more preferably, in a range of about 25 to about 200 m.
When the
thickness of the first adhesive layer exceeds 3,000 m, the pressing force
exerted on the
adhesive tape is dispersed when the adhesive tape is stuck to the material,
whereby the
adhesive tape fails to suitably follow up the rugged structure of the
material. Besides, the
pulling resistance becomes so great that the peeling operation by pulling
becomes
substantially impossible.
When the adhesive tape having the first adhesive layer is to be pulled and
peeled
off the surface of the material while being stretched, the adhering force of
the first
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adhesive layer to the material is smaller than the breaking stress of when the
adhesive tape
having the first adhesive layer is subjected to the tensile test. If concrete
numerical values
are described, the adhering force of when the first adhesive layer is to be
pulled and peeled
off the material is, typically, 1/1.5 or smaller and, preferably, 1/2.0 or
smaller of the
breaking stress of when the second adhesive element having the second adhesive
layer is
subjected to the tensile testing.
In the adhesive tape of the present invention, the total thickness of the
first
adhesive layer and the second adhesive layer can be varied over a wide range.
Typically,
the total thickness of these adhesive layers is in a range of about 25 to
about 3,000 m
and, more preferably, in a range of about 50 to 1,000 m. When the total
thickness of the
adhesive layers becomes not larger than 25 m, the tensile breaking strength
becomes
substantially smaller than the adhering strength, and it becomes impossible to
execute the
peeling operation by pulling. - Conversely, when the total thickness becomes
greater than
3,000 m, the tensile resistance becomes so great that the peeling operation
by pulling
cannot be executed.
In the adhesive tape and in the adhesive element of the present invention, the
adhesive layers which are the uppermost layers, e.g., the first adhesive layer
and the third
adhesive layer, may be used in their own forms. It is, however, desired to use
them after
the adhesive surfaces of the adhesive layers have been covered, typically,
with a peeling
paper (also called peeling liner or release liner). Upon covering the adhesive
layers with
the peeling papers, the adhesive tape can be easily handled and rolled. As the
peeling
paper, there can be exemplified a paper or a plastic film treated with a
silicone compound
or the like compound for parting.
The adhesive tape according to the present invention can be produced according
to
any method that has heretofore been generally used for the production of
pressure-
sensitive adhesive tapes. For instance, the adhesive composition can be
directly applied
onto one or both surfaces of the base member. Or, the adhesive l'ayer may be
formed as a
separate independent layer and may be laminated on the base member. As the
method of
application, there can be employed an ordinarily used method, such as knife-
coating
method, hot-melting method or the like method. In order to improve the
adhesion of the
adhesive layer on the base member, the surfaces of the base member may be
treated with a
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primer prior to the step of coating or the step of lamination. Other
pretreatment may be
effected instead of the treatment with the primer. The pretreatment can be
conducted by
using a reactive chemical adhesion accelerator, such as hydroxyethyl acrylate,
hydroxyethyl methacrylate or any other reactive species of a low molecular
weight. The
base member is made of a polymer film, and a corona discharge treatment is
generally
preferred.
The adhesive tape according to the present invention features an excellent
balance
between the adhering force and the cohesive force, and can be advantageously
used for a
variety of materials. It can be advantageously used for the wall paper, too.
Attention can
be given to that the adhesive tape is capable of solving great problems
maintaining
balance, such as mutual action to the vinyl chloride that constitutes the
material thereof,
preventing a drop in the adhering performance caused by the oozing of a
plasticizer from
the material, and performance that follows up various ruggedness in the
surface which
affects the appearance.
The object for applying the adhesive tape of the invention is not limited to
the
vinyl chloride-type material only which contains a plasticizer but can also be
applied to
the materials of various types, such as a wall paper or a film having rugged
patterns in the
surface thereof to a conspicuous degree, a sheet, a mortar wall, a lysine-
finished wall or a
concrete wall, that have rugged patterns in the surfaces thereof to a
conspicuous degree,
and to the materials of which the surfaces have been roughly treated: Namely,
the
adhesive tape of the invention can be strongly stuck to the materials and can
be peeled off
without damaging the materials. Though not limited thereto only, the material
in the form
of a film which is suited for putting the invention into practice may be an
ethylene/vinyl
alcohol copolymer resin film and a styrene/(meth)acrylic copolymer resin film.
The
material to be adhered referred to here includes a vinyl chloride-type wall
paper including
a plasticizer that is described above.
The above noticeable effects are expected for the adhesive tape of the
invention.
Therefore, the adhesive tape can be advantageously applied to various
materials ranging
from soft articles through up to hard articles, and is capable of providing
adhered
structures having excellent properties. For instance, the adhesive tape of the
present
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invention can be advantageously used in a multiplicity of technical fields
including the
following categories:
(1) Mounting use, such as mounting on a wall, forming a side portion of the
body
of an automobile, handle grip, etc.;
(2) Indication use, such as road sign, marking for automobiles, traffic
marking,
reflection sheet, etc.;
(3) Coupling use, such as adhering two or more contains or boxes;
(4) Closing use, such as sealing a container, sealing a box, sealing a food or
beverage container, sealing a diaper, sealing a surgical drape, etc.;
(5) Removable labels, such as price label (price tag), indicator label on a
container,
etc.; and
(6) Medical use, such as bandage and the like.
As particularly useful examples, the adhesive tape of the present invention
can be
advantageously applied to a vinyl chloride-type material and, particularly, a
material made
of a vinyl chloride resin. The material to be adhered includes molded articles
to which
particular shapes have been imparted and any other articles. Preferred
materials include,
for example, a sheet, i.e., a sheet-like or film-like article and,
particularly, a wall paper and
the like articles. This is because these articles usually contain a
plasticizer as represented
by a vinyl chloride sheet. In the conventional adhesive tapes, therefore, the
plasticizer is a
serious cause of dropping the adhesiveness of the adhesive tape. In the case
of the
adhesive tape of the invention, when the adhesive sheet is stuck to a vinyl
chloride sheet or
any other similar sheet containing a plasticizer, it has been found that the
adhesiveness is
not adversely affected and the stretch-release performance is stably
maintained, too. The
adhesive tape of the present invention can be strongly stuck to the vinyl
chloride-type wall
paper that contains the plasticizer and can, further, be peeled off the wall
paper without
damaging the wall paper.
In addition, the present inventors have discovered that when the adhesive tape
of
the present invention is produced while improving the above-mentioned first
component
(cohesive component) and the second component (basic component), the adhesive
tape
can be advantageously applied even to the materials of various types having
rugged
patterns in the surfaces thereof to a conspicuous degree or of which the
surfaces have been
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roughly treated, such as a wall paper, a sheet, a film, a mortar wall, a
lysine-finished wall
and a concrete wall. The adhesive tape of the present invention can not only
be strongly
stuck to the material having a conspicuous rigged pattern in the surface
thereof but also be
peeled off the material without damaging the material. The rugged pattern or
the rugged
structure referred to in the present invention includes various forms. When,
for example,
reference is made to the wall paper, there can be exemplified an emboss
working pattern, a
foamed emboss working pattern, a mesh pattern and a lattice pattern formed on
the
surfaces thereof.
That is, when a copolymer of an alkyl (meth)acrylate ester or a derivative
thereof
and a nitrogen-containing vinyl monomer is used as the nitrogen-containing
(meth)acrylic
copolymer that constitutes the second component and when the alkyl
(meth)acrylate ester
contains an isooctyl (meth)acrylate ester and a butyl (meth)acrylate ester,
the adhesive
tape of the present invention can be particularly advantageously applied to
the
conspicuously rugged wall papers. In recent years, in particular, there have
been placed in
the market many wall papers having diversified surface shapes from the
standpoint of
appearance inclusive of the wall papers having conspicuous ruggedness in the
surface.
Therefore, the adhesive tape of the present invention will find an increased
probability of
utilization.
The isooctyl (meth)acrylate ester and the butyl (meth)acrylate ester can be
copolymerized together being used at various ratios and are, usually, used at
a ratio of,
desirably, about 80:20 to about 0:100.
In the adhesive tape of the invention, further, an elastomer having a
conjugated
double bond is further added to the styrene block copolymer used as the first
component to
improve the adhering force without lowering the cohesive force. Here, the
elastomer
having a conjugated double bond that is additionally used includes various
elastomers but
is, desirably, a polybutadiene, a polyisoprene or a combination thereof. It is
desired that
the elastomer has a high molecular weight which is, usually, in a range of
about 1,000 to
about 2,000,000 and, desirably, in a range of about 1,000 to about 1,000,000.
When the
elastomer of a high molecular weight is added to the cohesive component, a
process oil
may not be used.
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The adhesive tape of the present invention can be advantageously used even for
the
materials to be adhered made of various soft or hard materials, such as glass,
ceramics,
tile, plastics, concrete, lumber (coated lumber, laminated board, particle
board), stone
member and metal member. Further, the material to be adhered is in many cases
used in
places of an elevated temperature and an elevated humidity (in other words, in
a humid
and hot environment) such as in kitchen and bathroom. Even when the adhesive
tape of
the invention is stuck to the material in such environments, the adhesiveness
and stretch-
release performance of the adhesive tape are not impaired.
The invention is further concerned with an article-attaching kit using the
adhesive
tape of the present invention. Fig. 6 is a diagram schematically illustrating
an article-
attaching kit of the invention. The article-attaching kit 30 that is shown is
used for
attaching a hook 53 which is an article to be attached to the wall member, and
where the
hook 53, the first adhesive element 10-1 and the second adhesive element 10-2
are placed
on a support member (thick paper) 31, and are fixed by being covered with a
transparent
plastic film (not shown). The first adhesive element 10-1 has its adhesive
surface covered
with a peeling paper 14b, and the second adhesive element 10-2 is covered with
a peeling
paper 4b. To attach the hook 53 onto the wall member, the hook 53 and the
second
adhesive element 10-2 are taken out from the kit 30, and the second adhesive
element 10-2
is attached to the back side of the hook 53 via the third adhesive layer.
Next, the hook 53
is stuck to the wall member and is fixed thereto via the second adhesive layer
of the
second adhesive element attached to the hook 53. The first adhesive layer of
the first
adhesive element 10-1 is transferred and stuck to the wall member in advance.
Or, the first adhesive layer of the first adhesive element 10-1 is stuck to
the wall
member in advance, the second adhesive element 10-2 is stuck alone thereon
and, then, the
hook 53 is attached to the wall member via the third adhesive layer.
To remove the hook 53 from the wall member, as required, the adhesive tape is
simply pulled while holding the hook 53; i.e., the adhesive tape can be easily
peeled off
together with the hook 53 leaving no adhesive on the surface of the wall
member.
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EXAMPLES
Next, the invention will be described with reference to Examples. Here, the
invention is in no way limited to these Examples only, as a matter of course.
First, summarized below are abbreviations of starting substances used in the
following preparation examples.
BA: Butyl acrylate (manufactured by Wako Junyaku Kogyo Co.).
AA: Acrylic acid (manufactured by Wako Junyaku Kogyo Co.).
Vim: 1-Vinylimidazole (manufactured by Tokyo Kasei Kogyo Co.).
EtOAc: Ethyl acetate (manufactured by Wako Junyaku Kogyo Co.).
StyM: Styrene macromer having the following properties and structural formula
prepared
according to a method described in Japanese Unexamined Patent Publication
(Kokai) No.
59-75975, page 14, right upper column, monomer "C-3",
(Properties) A solution containing 50% by weight of a methacrylate-terminated
polystyrene/cyclohexane,
Weight average molecular weight = 13,000 (based on GPC),
(Structural formula) CH2=C(CH3)C(=O)-O-CH2CH2-(polystyrene)-CH2CH2CH2CH3.
ADVN: 2,2'-Azobis(2,4-dimethylvaleronitrile)(azo-type polymerization
initiator,
manufactured by Wako Junyaku Kogyo Co.).
FinapreneTM411: Styrene/butadiene/styrene block copolymer (manufactured by
Fina Oil
and Chemical Co.).
AsapreneTM 1205: Styrene/butadiene block copolymer (manufactured by Asahi
Kasei Co.).
PiccolyteTMA-135: Adhesiveness-imparting agent (manufactured by Hercules
Chemical
Co.).
IrganoxTM1330: Phenolic anti-oxidant (manufactured by Ciba Specialty Chemicals
Co.).
ShellflexTM371N: Naphthene-type oil (manufactured by Shell Chemical Co.).
Preparation of Example 1
Preparation of an acrylic adhesive agent.
156 Grams of butyl acrylate, 22.5 g of 1-vinylimidazole, 1.13 g of acrylic
acid and
90 g of styrene macromer were successively added into a 2000-m1 separable
flask. Next,
0.27 g of 2,2'-azobis(2,4-dimethylvaleronitrile) and 480 g of ethyl acetate
were thrown
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therein. The polymerization was conducted in a constant-temperature water
vessel
maintained at 50 C for 8 hours while blowing a nitrogen gas from the lower
portion of the
blended solution by using a Pasteur pipette.
Prenaration of Example 2
Preparation of a rubber-type adhesive agent.
A rubber-type adhesive agent having the following composition was prepared.
FinapreneTM411 65.0 parts by weight
AsapreneTM 1205 65.0 parts by weight
PiccolyteTMA-135 129.9 parts by weight
IrganoxTM1330 2.6 parts by weight
ShellflexTM371N 6.6 parts by weight
Toluene 487.5 parts by weight
Production of Example 1
A double-sided adhesive tape with a pulling tab was prepared so as to be used
as
the second adhesive element in the production of the adhesive tape. The double-
sided
adhesive tape prepared here possessed the same constitution as the second
adhesive
element 10-2 of Fig. 3, and is commercially available as COMMANDTM TAB from
Sumitomo 3M Co., Ltd.
The COMMANDTM TAB used here possessed the following layer constitution.
Support member (core) 11 Foamed polyethylene film
Support member (surface layer) 12a Polyethylene film
Support member (surface layer) 12b Polyethylene film
Third adhesive layer 2a Rubber-type adhesive
Second adhesive layer 2b Rubber-type adhesive
Thickness (total) 950 m
The individual adhesive layers are covered with a PET peeling liner.
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Production of Example 2
There were provided the following four kinds of transfer sheets with an
adhesive
layer for use as the first adhesive element in the production of the adhesive
tapes.
Sample 1:
A double-sided adhesive tape commercially available from Sumitomo Three-M
Co. as ultra-powerful double-sided tape (for glasses and acrylics). The
adhesive layer was
a copolymer of an isooctyl acrylate and an acrylic acid, and possessed a
thickness of 1,000
m.
Samnle 2=
The acrylic adhesive prepared in the Preparation Example 1 above and the
rubber-
type adhesive prepared in the Preparation Example 2 above were mixed together
at a ratio
of 3:7, and the mixture was applied onto a PET peeling liner maintaining a
thickness of 70
m. For easy use, further, the adhesive layer that was formed was covered with
another
PET peeling liner.
Sample 3:
The rubber-type adhesive prepared in the Preparation Example 2 above was
applied onto a PET peeling liner maintaining a thickness of 70 m. For easy
use, further,
the adhesive layer that was formed was covered with another PET peeling liner.
Sample 4:
A double-sided adhesive tape commercially available from Sumitomo Three-M
Co. as COMMANDTM TAB (see above). The adhesive layer was a rubber-type
adhesive
and possessed a thickness of 950 m.
Example 1 (Reference Example).
Ah adhesive sheet same as the adhesive sheet of the invention was prepared but
without using the first adhesive element (first adhesive layer) and was put to
the tensile
test and to the holding test.
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There was provided, as a material to be adhered, a wall paper of a vinyl
chloride
resin (trade name "SP9903", manufactured by Sangetsu Co.) which was emboss-
worked
on the surface thereof and having a thickness of 2.0 mm as shown in Fig. 7,
which was,
then, stuck to an aluminum plate 51 with an adhesive. Next, a double-sided
adhesive tape
(COMMANDTM TAB) prepared in the Preparation Example 1 was cut into a width of
16
mm and a length of 16 mm. The thus obtained double-sided sample adhesive tape
10 was
stuck to the wall paper 52 after having removed the peeling liner therefrom.
Tensile Test:
The aluminum plate 51 was mounted on the test device, and the double-sided
sample adhesive tape 10 was press-adhered onto the wall paper 52 by rolling a
10-kg
stainless steel roller one round trip. Next, by nipping the tab, the double-
sided sample
adhesive tape 10 was pulled at a peeling angle of 2 and a pulling rate of 300
mm/min. to
peel it off the wall paper 52. The double-sided sample adhesive tape 10 was
measured for
its proportional limit, breaking point and breaking elongation to be 18 (NI15
mm), 44
(N/15 mm) and 750 (%), respectively, as shown in Table 1 below. The tensile
strength has
been converted into a width of 16 mm. After the tensile test, the wall paper
was observed
for its surface but there was recognized no adhesive that was remaining.
Holding Test:
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
as
described above, a hook 53 made of a styrol resin was attached as shown in
Fig. 7. The
hook 53 used here was the COMMANDTM HOOK (M-size) manufactured by Sumitomo
3M Co., Ltd. in combination with the COMMANDTM TAB. After attached to the wall
paper 52, the hook 53 was pressed with a static load of 10 kg for 30 seconds.
Next, a load W of 3.7 kg was hung from the hook 53. The time (minutes) for
holding the hook 53 using the double-sided sample adhesive tape 10 was
measured to be
472 minutes as shown in Table 1 appearing below.
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Example 2
The method described in Example 1 was repeated. In this Example, however, the
first adhesive layer of the first adhesive element was transferred onto the
wall paper prior
to sticking the double-sided sample adhesive tape onto the wall paper.
As described in Example 1, the wall paper 52 made of the vinyl chloride resin
was
stuck to the aluminum plate 51. Thereafter, the first adhesive layer (acrylic
adhesive) was
transferred onto a predetermined position of the wall paper 52 from the
transfer sheet
(sample 1) having the adhesive layer produced in the Production Example 2. The
transferred first adhesive layer measured 16 mm wide (measured width of 18 mm)
and 16
mm long. Next, the peeling liner was removed from the double-sided sample
adhesive
tape 10 that was obtained by cutting the double-sided adhesive tape provided
in the
Production Example 1 into 16 mm wide and 16 mm long. The double-sided sample
adhesive tape 10 was stuck to the wall paper 52.
Tensile Test:
The aluminum plate 51 was mounted on the test device, and the double-sided
sample adhesive tape 10 was press-adhered onto the wall paper 52 by rolling a
10-kg
stainless steel roller one round trip. Next, by nipping the tab, the double-
sided sample
adhesive tape 10 was pulled at a peeling angle of 2 and a pulling rate of 300
mm/min. to
peel it off the wall paper 52. The double-sided sample adhesive tape 10 was
measured for
its proportional limit, breaking point and breaking elongation to be 1.8 (N/15
mm), 16
(N/15 mm) and 850 (%), respectively, as shown in Table 1 below. After the
tensile test,
the wall paper was observed for its surface but there was recognized no
adhesive that was
remaining. Namely, in this Example, it was learned that both the first and
second adhesive
layers were favorably peeled off simultaneously.
Holding Test:
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (acrylic adhesive) as described above, a hook 53 made
of a styrol
resin was attached and was pressed with a static load of 10 kg for 30 seconds.
Next, a load
W of 3.7 kg was hung from the hook 53. The time (minutes) for holding the hook
53
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using the double-sided sample adhesive tape 10 was measured to be 573 minutes
as shown
in Table 1 appearing below.
Example 3
The method described in Example 1 was repeated. In this Example, however, the
first adhesive layer of the first adhesive element was transferred onto the
wall paper before
sticking the double-sided sample adhesive tape onto the wall paper.
As described in Example 1, the wall paper 52 made of the vinyl chloride resin
was
stuck to the aluminum plate 51. Thereafter, the first adhesive layer
(rubber/acrylic
blended adhesive) was transferred onto a predetermined position of the wall
paper 52 from
the transfer sheet (sample 2) having the adhesive layer produced in the
Production
Example 2. The transferred first adhesive layer measured 16 mm wide (measured
width of
10 mm) and 16 mm long. Next, the peeling liner was removed from the double-
sided
sample adhesive tape 10 that was obtained by cutting the double-sided adhesive
tape
provided in the Production Example 1 into 16 mm wide and 16 mm long. The
double-
sided sample adhesive tape 10 was stuck to the wall paper 52.
Tensile Test:
The aluminum plate 51 was mounted on the test device, and the double-sided
sample adhesive tape 10 was press-adhered onto the wall paper 52 by rolling a
10-kg
stainless steel roller one round trip. Next, by nipping the tab, the double-
sided sample
adhesive tape 10 was pulled at a peeling angle of 2 and a pulling rate of 300
mm/min. to
peel it off the wall paper 52. The double-sided sample adhesive tape 10 was
measured for
its proportional limit, breaking point and breaking elongation to be 0.64
(NI15 mm), 4
(N/15 mm) and 800 (%), respectively as shown in Table 1 below. After the
tensile test,
the wall paper was observed for its surface but there was recognized no
adhesive that was
remaining. Namely, in this Example, it was learned that both the first and
second adhesive
layers were favorably peeled off simultaneously.
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Holding Test:
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (rubber/acrylic blended adhesive) as described above,
a hook 53
made of a styrol resin was attached and was pressed with a static load of 10
kg for 30
seconds. Next, a load W of 3.7 kg was hung from the hook 53. The time
(minutes) for
holding the hook 53 using the double-sided sample adhesive tape 10 was
measured to be >
25,000 minutes as shown in Table 1 appearing below.
Example 4
The method described in Example 1 was repeated. In this Example, however, the
first adhesive layer of the first adhesive element was transferred onto the
wall paper before
sticking the double-sided sample adhesive tape onto the wall paper.
As described in Example 1, the wall paper 52 made of the vinyl chloride resin
was
stuck to the aluminum plate 51. Thereafter, the first adhesive layer (rubber-
type adhesive)
was transferred onto a predetermined position of the wall paper 52 from the
transfer sheet
(sample 3) having the adhesive layer produced in the Production Example 2. The
transferred first adhesive layer measured 16 mm wide (measured width of 10 mm)
and 16
mm long. Next, the peeling liner was removed from the double-sided sample
adhesive
tape 10 that was obtained by cutting the double-sided adhesive tape provided
in the
Production Example 1 into 16 mm wide and 16 mm long. The double-sided sample
adhesive tape 10 was stuck to the wall paper 52.
Tensile Test:
The aluminum plate 51 was mounted on the test device, and the double-sided
sample adhesive tape 10 was press-adhered onto the wall paper 52 by rolling a
10-kg
stainless steel roller one round trip. Next, by nipping the tab, the double-
sided sample
adhesive tape 10 was pulled at a peeling angle of 2 and a pulling rate of 300
mm/min. to
peel it off the wall paper 52. The double-sided sample adhesive tape 10 was
measured for
its proportional limit, breaking point and breaking elongation to be 0.32
(N/15 mm), 3.36
(NI15 mm) and 840 (%), respectively, as shown in Table 1 below. After the
tensile test,
the wall paper was observed for its surface but there was recognized no
adhesive that was
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remaining. Namely, in this Example, it was learned that both the first and
second adhesive
layers were favorably peeled off simultaneously.
Holding Test:
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (rubber-type adhesive) as described above, a hook 53
made of a
styrol resin was attached and was pressed with a static load of 10 kg for 30
seconds. Next,
a load W of 3.7 kg was hung from the hook 53. The time (minutes) for holding
the hook
53 using the double-sided sample adhesive tape 10 was measured to be > 10,000
minutes
as shown in Table 1 appearing below.
Examgle 5
The method described in Example 1 was repeated. In this Example, however, the
first adhesive layer of the first adhesive element was transferred onto the
wall paper before
sticking the double-sided sample adhesive tape onto the. wall paper.
As described in Example 1, the wall paper 52 made of the vinyl chloride resin
was
stuck to the aluminum plate 51. Thereafter, the first adhesive layer (rubber-
type adhesive)
was transferred onto a predetermined position of the wall paper 52 from the
transfer sheet
(sample 4) having the adhesive layer produced in the Production Example 2. The
transferred first adhesive layer measured 16 mm wide (measured width of 16 mm)
and 16
mm long. Next, the peeling liner was removed from the double-sided sample
adhesive
tape 10 that was obtained by cutting the double-sided adhesive tape provided
in the
Production Example I into 16 mm wide and 16 mm long. The double-sided sample
adhesive tape 10 was stuck to the wall paper 52.
The aluminum plate 51 was mounted on the test device, and the double-sided
sample adhesive tape 10 was press-adhered onto the wall paper 52 by rolling a
10-kg
stainless steel roller one round trip. Next, by nipping the tab, the double-
sided sample
adhesive tape 10 was pulled at.a peeling angle of 2 and a pulling rate of 300
mm/min. to
peel it off the wall paper 52. The double-sided sample adhesive tape 10 was
measured for
its proportional limit, breaking point and breaking elongation to be 18 (N/15
mm), 44
(Nl15 mm) and 750 (%), respectively, as shown in Table 1 below. After the
tensile test,
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the wall paper was observed for its surface and it was confirmed that the
first and second
adhesive layers had not been peeled off, simultaneously.
Holding Test:
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (rubber-type adhesive) as described above, a hook 53
made of a
styrol resin was attached and was pressed with a static load of 10 kg for 30
seconds. Next,
a load W of 3.7 kg was hung from the hook 53. The time (minutes) for holding
the hook
53 using the double-sided sample adhesive tape 10 was measured to be > 10,000
minutes
as shown in Table 1 appearing below.
Table 1
Example 1 Example 2 Example 3 Example 4 Reference 5
(Ref.
Exam le
ensile limit 18 1.8 0.64 0.32 18
/15 mm)
reaking point 44 16 4 3.36 44
(N/ 15 mm)
reaking 750 850 800 840 750
elongation (%)
Simultaneous - acceptable acceptable acceptable ot acceptable
eeling
"olding min. 472 573 25000 10000 10000
. As will be understood from the test results described in Table I above, the
adhesive tape of the present invention can be strongly adhered to the material
and can,
further, be easily peeled off the material together with the first and second
adhesive layers.
From these results, it can be evaluated that the adhesive tape of the present
invention is a
totally excellent peelable adhesive tape. From these test results, further, it
will be learned
that the conditions for simultaneously peeling the first and second adhesive
layers are such
that the first adhesive layer (adhesive layer of the transfer sheet) exhibits
a tensile test
value (breaking stress: maximum value) which is smaller than that of the
second adhesive
layer (adhesive layer of the double-sided sample adhesive tape).
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Example 6
The method described in Example 1 was repeated to test the holding force. In
this
Example, however, the first adhesive layer of the first adhesive element was
transferred
onto the wall paper or onto the second adhesive element (double-sided sample
adhesive
tape) before sticking the double-sided sample adhesive tape onto the wall
paper. There
were used the following 16 kinds of wall papers.
Wall paper 1: Vinyl chloride resin, lattice-patterned surface, LY9515 (product
number),
manufactured by Lilicala Co.
Wall paper 2: Vinyl chloride resin, amorphous foamed emboss-patterned surface,
LY9519
(product number), manufactured by Lilicala Co.
Wall paper 3: Vinyl chloride resin, amorphous foamed emboss-patterned surface,
LY952
(product number), manufactured by Lilicala Co.
Wall paper 4: Vinyl chloride resin, amorphous foamed emboss-patterned surface,
LY9540
(product number), manufactured by Lilicala Co.
Wall paper 5: Vinyl chloride resin, amorphous foamed ernboss-patterned
surface, LY9552
(product number), manufactured by Lilicala Co.
Wall paper 6: Vinyl chloride resin, emboss-patterned surface, SP9903 (product
number),
manufactured by Sangetsu Co.
Wall paper 7: Vinyl chloride resin, emboss-patterned surface, SP9904 (product
number),
manufactured by Sangetsu Co.
Wall paper 8: Vinyl chloride resin, mesh-patterned surface, SP9912 (product
number),
manufactured by Sangetsu Co.
Wall paper 9: Vinyl chloride resin, mesh-patterned surface, SP9917 (product
number),
manufactured by Sangetsu Co.
Wall paper 10: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9918 (product number), manufactured by Sangetsu Co.
Wall paper 11: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9919 (product number), manufactured by Sangetsu Co.
Wall paper 12: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9922 (product number), manufactured by Sangetsu Co.
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Wall paper 13: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9923 (product number), manufactured by Sangetsu Co.
Wall paper 14: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9926 (product number), manufactured by Sangetsu Co.
Wall paper 15: Vinyl chloride resin, amorphous foamed emboss-patterned
surface,
SP9932 (product number), manufactured by Sangetsu Co.
Wall paper 16: Vinyl chloride resin, emboss-patterned surface, SP9950 (product
number),
manufactured by Sangetsu Co.
For testing the holding force, there were used four kinds of weights W
weighing
5.06 kg, 4.7 kg, 3.7 kg and 3.0 kg.
Test 1
The wall paper 52 of vinyl chloride resin was stuck to the aluminum plate 51
as
described in Example 1. Next, the peeling liner was removed from the double-
sided
sample adhesive tape 10 obtained by cutting the double-sided adhesive tape
provided in
the Production Example 1 above into 25 mm wide and 56 mm long. Thereafter, the
first
adhesive layer (rubber/acrylic blended adhesive) was transferred from the
transfer sheet
(sample 2) having the adhesive layer produced in the Production Example 2
above onto
the second adhesive layer (rubber-type adhesive) which has been exposed of the
double-
sided sample adhesive tape 10. The area of the first adhesive layer that was
transferred
was 1,400 mm2, i.e., 25 mm wide and 56 mm long. After the first and second
adhesive
layers were laminated as described above, the double-sided sample adhesive
tape 10 was
stuck to the predetermined position of the wall paper 52.
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (rubber/acrylic blended adhesive) as described above,
a hook 53
made of a styrol resin was attached and was pressed with a static load of 10
kg for 30
seconds. Next, the loads W of different weights were hung from the hook 53.
The time
(minutes) for holding the hook 53 using the double-sided sample adhesive tape
10 was
measured for each of the loads W. The holding (minutes) was repetitively
measured 7
3 0 times and was regarded to be "acceptable" when the average value was >
25,000 minutes,
and the load endurance was calculated. As shown in Table 2 below, despite of
having the
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width of 25 mm, not all of the tested adhesive tapes could endure the load of
3.7 kg but
two of them could not endure.
Test 2
The wall paper 52 of vinyl chloride resin was stuck to the aluminum plate 51
as
described in Example 1. Next, the first adhesive layer (rubber/acrylic blended
adhesive)
was transferred from the transfer sheet (sample 2) having the adhesive layer
produced in
the Production Example 2 above onto a predetermined position of the wall paper
52. The
transfer sheet was pushed onto the wall paper by using a plastic spatula so as
to be
transferred thereon. The area of the first adhesive layer that was transferred
was 720 mm2,
i.e., 16 mm wide and 45 mm long. Next, the peeling liner was removed from the
double-
sided sample adhesive tape 10 that was obtained by cutting the double-sided
adhesive tape
provided in the Production Example 1 above into 16 mm wide and 45 mm long.
Thereafter, the double-sided sample adhesive tape 10 was stuck to the wall
paper 52 being
overlapped on the first adhesive layer.
After the double-sided sample adhesive tape 10 was stuck to the wall paper 52
via
the first adhesive layer (rubber/acrylic blended adhesive) as described above,
a hook 53
made of a styrol resin was attached and was pressed with a static load of 10
kg for 30
seconds. Next, the loads W of different weights were hung from the hook 53.
The time
(minutes) for holding the hook 53 with the double-sided sample adhesive tape
10 was
measured for each of the loads W. The holding (minutes) was repetitively
measured 7
times and was regarded to be "acceptable" when the average value was > 25,000
minutes,
and the load endurance was calculated. As shown in Table 2 below, the tested
adhesive
tapes all endured the load of 3.7 kg despite of having changed the width of
the tape down
to 16 mm. Besides, 14 of them could endure the load of 5.06 kg.
Table 2
Load (kg) Test 1 Test 2
5.06 0 14
4.7 0 1
3.7 14 1
3.0 2 0
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As will be understood from the test results of Table 2 above, the adhesive
tape of
the present invention offers very favorable load endurance when the first
adhesive layer is
stuck to the material and, next, the second adhesive layer (second adhesive
element) is
laminated on the first adhesive layer, rather than when the first adhesive
layer of the first
adhesive element is laminated readily on the second adhesive layer of the
second adhesive
element.
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