Note: Descriptions are shown in the official language in which they were submitted.
20~0~13
A PLATE ROLI. AND AN ADHESIVE SHEET THEREEOR
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a novel plate roll
attached with a printing plate made of resin by means of
adhesive and a novel adhesive sheet utilized for attaching
the printing plate to the base plate roll.
2. Prior art
A printing plate leaf made of resin is attached to a
base plate roll to form a plate roll by means of a double
faced adhesive sheet and continuous printing is made by
rotating the plate roll.
Adhesives generally utili~ed for attaching the printing
plate leaf to the base plate roll have strong adhesive
ability and the printing plate leaf is not easily detached
from the base plate roll after the printing is finished.
Occasionally, the printing plate leaf made of resin is torn
up during the operation of detaching. A part of the
adhesive and the adhesive sheet usually remains on the
surface of the base plate roll or the printing plate and
removal of the remaining things takes time.
20~0213
S~MMARY OF Tl-IE INVENTION
The present invention accordinglY has an obiect to
provide a plate roll in which printing plate is firmly
attached during the printing operation, the printing plate
is easily detached from the base plate roll after the
printing operation is finished and remaining adhesive is
easily removed. Another object of the invention is to
provide an adhesive sheet utilized for the plate roll.
Thus, the plate roll attached with a printing plate
made of resin by means of an adhesive of the present
invention is characterized in that a photo curable adhesive
which loses adhesive ability by curing by irradiation of
electromagnetic wave or electron beam is used as the
adhesive.
The plate roll attached with a printing plate made of
resin by means of an adhesive of the invention is also
characterized in that a water s~elling adhesive which loses
adhesive ability by swelling by water is used as the
adhesive.
The adhesive sheet utilized for attaching a printing
plate made of resin to a base plate roll of the invention
is characterized in that the adhesive sheet comprises a
removable sheet and a photo curable adhesive which loses
adhesive ability by curing by irradiation of
~ o ~
electromagnetic wave or electron beam and is coated on one
face of tlle removable sheet.
The adhesive sheet utilized for attaching a printing
plate made of resin to a base plate roll of the invention
is also characterized in that the adhesive sheet comprises
a supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
adhesive layer coated at least on one face of the
supporting sheet comprises a photo curable adhesive which
loses adhesive ability by curing by irradiation of
electromagnetic wave or electron beam and that the
removable sheet is attached at least on one face of the
adhesive sheet.
The adhesive sheet utilized for attaching a printing
plate made of resin to a base plate roll of the invention
is also characterized in that the adhesive sheet comprises
a removable sheet and a water swelling adhesive which loses
adhesive ability by swelling by water and is coated on one
face of the removable sheet.
The adhesive sheet utilized for attaching a printing
plate made of resin to a base plate roll of the invention
is also characterized in that the adhesive sheet comprises
a supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
2~ 2~3
adhesive layer coated at least on one face of the
supporting sheet comprises a water swelling adhesive which
loses adhesive ability by swelling by water and that the
removable sheet is attached at least on one face of the
adhesive sheet.
The adhesive sheet utilized for attaching a printing
plate made of resin to a base plate roll of the invention
is also characterized in that the adhesive sheet comprises
a supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
adhesive layer coated on one face of the supporting sheet
comprises a photo curable adhesive which loses adhesive
ability by curing by irradiation of electromagnetic wave or
electron beam, that the adhesive layer coated on the other
face of the supporting sheet comprises a water swelling
adhesive which loses adhesive ability by swelling by water
and that the removable sheet is attached at least on one
face of the adhesive sheet.
Other and further objects, features and advantages of
the invention will appear more fully from the following
description.
DETAII,eD DeSCRIPTION OF TIIE PREFERRED EMBODIMENTS
It was considered by the present inventors that the
2~40213
antinomic problem that a printin~ plate is firmly attached
to base plate roll during the printing operation and easily
detached after the printing operation is finished can be
solved only by changing the adhesive ability of the
adhesive utilized between the time of attachment and the
time of detachment. For the purpose of changing the
adhesive ability of the adhesive utilized, a mechanism of
decreasing the adhesive ability by curing the adhesive by
the action of electromagnetic wave and another mechanism of
decreasing the adhesive ability by swelling the adhesive by
water were considered. These considerations led to the
completion of the present invention.
The present invention as a whole comprises the
following seven inventions:
Invention 1: A plate roll attached with a printing plate
made of resin by means of an adhesive which is
characterized in that a photo curable adhesive which loses
adhesive ability by curing by irradiation of
electromagnetic wave or electron beam is used as the
adhesive.
Invention 2: A plate roll attached with a printing plate
made of resin by means of an adhesive which is
characterized in that a water swelling adhesive which loses
adhesive ability by swelling by water is used as the
20~02~3
adhesive.
Invention 3: An adhesive sheet utilized for attaching a
printing plate made of resin to a base plate roll which is
characterized in that the adhesive sheet comprises a
removable sheet and a photo curable adhesive which loses
adhesive ability by curing by irradiation of
electromagnetic wave or electron beam and is coated on one
face of the removable sheet.
Invention 4: An adhesive sheet utilized for attaching a
printing plate made of resin to a base plate roll which is
characterized in that the adhesive sheet comprises a
supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
adhesive layer coated at least on one face of the
supporting sheet comprises a photo curable adhesive which
loses adhesive ability by curing by irradiation of
electromagnetic wave or electron beam and that the
removable sheet is attached at least on one face of the
adhesive sheet.
Invention 5: An adhesive sheet utilized for attaching a
printing plate made of resin to a base plate roll which is
characterized in that the adhesive sheet comprises a
removable sheet and a water swelling adhesive which loses
adhesive ability by swelling by water and is coated on one
2~40213
face of the removable sheet.
Invention 6: An adhesive sheet utilized for attaching a
printing plate made of resin to a base plate roll which is
characterized in that the adhesive sheet comprises a
supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
adhesive layer coated at least on one face of the
supporting sheet comprises a water swelling adhesive which
loses adhesive ability by swelling by water and that the
removable sheet is attached at least on one face of the
adhesive sheet.
Invention 7: An adhesive sheet utilized for attaching a
printing plate made of resin to a base plate roll which is
characterized in that the adhesive sheet comprises a
supporting sheet, a removable sheet and adhesive layers
coated on both faces of the supporting sheet, that the
adhesive layer coated on one face of the supporting sheet
comprises a photo curable adhesive which loses adhssive
ability by curing by irradiation of electromagnetic wave or
electron beam, that the adhesive layer coated on the other
face of the supporting sheet comprises a water swelling
adhesive which loses adhesive ability by swelling by water
and that the removable sheet is attached at least on one
face of the adhesive sheet.
2~213
The kind of the printing plate made of resin and the
base pla~e roll utilized in the invention is not
particularly limited but any kind may be utilized.
The adhesive utilized in the invention 1 is not
particularly limited so long as the adhesive loses its
adhesive ability by irradiation of electromagnetic wave,
such as ultraviolet light, visible light, ~-ray, X-ray
infrared light and the like, or electron beam. When
electromagnetic wave having weaker penetrating power
through substances, such as ultraviolet light, visible
light and infrared light, is utilized, the printing plate
made of resin is desirably more transparent.
The loss of adhesive ability in the invention means a
remarkable decrease of adhesive strength. It is the
condition that the adhesive strength is so lower than the
original strength that the printing plate can be detached
easily by hands.
Rxamples of the photo curable adhesive of the invention
are: (1) an adhesive comprising polymer having two or more
photo reactive unsaturated bonds as the main component of
the adhesive and (2) an adhesive which is prepared by
compounding a photo sensitive monomer and like other
reactive low molecular weight compounds into a conventional
adhesive.
20-~0213
~ xamples of the photo curable adhesive (1) are: a
polymer prepared by reacting glycidyl (meth)acrylate with
acid groups in copolymer of acrylic ester or methacrylic
ester and a small amount of acrylic acid or methacrylic
acid; and a polymer prepared by reacting half-urethane with
a mixture of ~-hydroxyethyl (meth)acrylate having
hydroxylgroup in the molecule with copolymer of acrylic
ester or methacrylic ester and a small amount of acrylic
acid or methacrylic acid. The hal~-urethane is prepared by
the reaction of polyisocyanate with a monomer containing
hydroxyl group. Photo reactive groups are introduced into
the polymer by these reactions.
Rxamples of the photo curable adhesive (2) are: a
compound prepared by mixing a photo sensitive monomer with
conventional rubber or acrylic adhesive in the amount from 1
to 50 weight %.
Rxamples of the photo sensitive monomer are:
(meth)arylic esters having two or more double bonds in the
molecule, such as 1,4-butylene glycol diacrylate,
1,6-hexane glycol diacrylate, neopentyl glycol diacrylate,
(poly)ethylene glycol diacrylate, trimethylolpropane
tri(meth)acrylate, tetramethylolmethane tetracrylate and
the like.
It is desirable that a photo sensitizer is added to
2~ 2~3
the photo curable adhesive to enhance the reaction rate of
curing. Examples o~ such photo sensitizer are: diacetyl,
benzil, benzophenone, benzoin, bromoacetophenone,
chloroacetone, benzoquinone, anthraquinone,
2-ethylanthraquinone, benzoin isopropyl ether, benzoin
ethyl ether and the like other organic carbonyl compounds.
The photo sensitizer is generally utilized in the amount
from 0.1 to 10 weight % of the adhesive.
After printing is finished, the plate roll of the
invention 1 is irradiated by electromagnetic wave or
electron beam from the surface of the printing plate made
of resin attached on the base plate roll. Because the
adhesive between the printing plate and the base plate roll
is cured by the irradiation, the adhesive ability of the
adhesive is lost and the printing plate made of resin is
easily detached from the base plate roll.
The source of the irradiation is not particularly
limited so long as the irradiation cures the adhesive and
can be appropriately selected according to the adhesive
utilized. Ultraviolet light is preferable because of
efficiency of the irrdiation time and simplicity of
apparatus.
The kind of the water swelling adhesive of the
invention 2 is not particularly limited so long as the
1 0
2~2~3
adhesive loses adhesive abilily by swelling with water.
An example of the water swelling adhesive is an
adhesive described in Japanese Patent Pu~lication Showa
49-23294 which is described in the following.
The adhesive comprises (A) one or more than one kinds
of nonionic surface active agent which comprises ethylene
oxide group as the hydrophillic group and (B) one or more
than one kinds of copolymer composed of 40 to 99 mole % of
one or more than one kinds of constituent unit having the
formula (I) and 60 to 1 mole % of one or more than one
kinds of constituent unit having the formula (II) and,
optionally according to the needs, carboxyl groups
comprised in the component (B) are crosslinked by a
crosslinking agent reacting with carboxyl group, such as
zinc acetate and magnesium chloride;
H R~
- C - C -
H R2 (I)
wherein R, is hydrogen, chlorine or lower alkyl group, R2
is hydrogen, chlorine, lower alkyl group, -OCOR3, -OR3,
-COOR3, phenyl, tolyl, -CN, -CONH2, -CONHCH20H, -CH20H,
-C2H~OH, -OH or pyridyl and R~ is alkyl group of 1 to 8
carbon atoms;
2~0213
X Z
-- C -- C --
Y COOH (II)
uherein X, Y and Z may be the same kind or different kinds
selected from hydrogen, chlorine, lower alkyl group, -COOR4,
-COOH, -CH2COOH or -CH2COOR~ and R~ is alkyl group of 1 to ~
carbon atoms. Alkaline compounds, such as potassium
hydroxide, may be added when the adhesive is crosslinked by
the crosslinking agent
~ xamples of the nonionic surface active agent which
comprises ethylene oxide group as the hydrophillic group of
the component (A) are:
(1) OH(C2H40)~(C3HBO)b(C2H40)cH, wherein a, b and c are
integers from 20 to 80;
(2) RA(C2H40)dH, wherein R is alkyl group of 6 to 18 carbon
atoms, alkylphenyl group having alkyl group of ~ to 20
carbon atoms or a group having the formula (III)
CH2CH2 ~
~ CH2CH2 H (or CH3) (III)
wherein A is oxygen, sulfur or -COO-, -CONH-,
-CON(C2H~O)dH-, -PO,H- or -PO~(C2H~O)dH- and d is an integer
from 2 to 80; and
1 2
2o4o~l3
(3) 0
H2C C~l-CH~OCOR
H(OC2H4)~-O-HC CH-O(C2H40).,.H
CH
OtC2H40)yH (IV)
wherein R is alkyl group of 6 to 18 carbon atoms and x, y
and z are integers of 2 to 40.
Preferable examples of the nonionic surface active
agent which comprises ethylene oxide group as the
hydrophillic group of the component (A) are: polyethylene
glycol nonylphenyl ether, polyethylene glycol sorbitane
monooleyL ester, polyethylene glycol lauryl ether, block
copolymer of polyethylene glycol and polypropylene glycol,
polyethylene glycol lauryl phenyl ether, polyethylene
glycol t-butyl phenyl ether and the like.
The constituent unit having the formula (I) of the
component (B) is introduced by using a monomer, such as
vinyl esters like vinyl acetate, methacrylic esters like
ethyl acrylate, ethylene, styrene, methyl vinyl ether,
vinyl chloride and acrylonitrile. The constituent unit
having the formula (II) of the component (B) is introduced
by using a monomer having carboxyl group, such as acrylic
acid, methacrylic acid, crotonic acid, itaconic acid,
maleic acid, fumaric acid, aconotic acid, monoalkyl maleic
1 3
2 1 3
acid, monoalkyl ~umaric acid, monoalkyl itaconic acid and
the like.
It is required that the component (A) and the component
(B) are compatible and the adhesive prepared swells with
water and, therefore, that the ratio of the component (A)
and the component (B) is within a definite range as
described in the cited reference.
Epoxy compounds of glycidyl derivative may be
optionally utilized with the component (A) and the
component (B).
Another example of the water swelling adhesive is an
adhesive described in Laid Open Japanese Patent Publication
Showa 59-157162 which is described ;n the following.
The adhesive comprises (A) water soluble polymer and
(B) (meth)acrylic ester monomer which gives water soluble
or water swelling polymer by polymerization.
An example of the water soluble polymer of the
component (A) is polymer prepared from a monomer having the
following formula (V):
o
CH2=CR5-C-(-O-R~3-) n~O~R7 (V)
wherein R~ is hydrogen or methyl group, Ro is alkylene
group of 2 to 4 carbon atoms, R7 is alkyl group of 1 or
more than 1 carbon atoms and n is an integer of 1 or more
1 a~
2 ~ 1 3
than 1, such as (meth)acrylic ester, acrylic acid,
vinylpyrrolidone, acrylamide, dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate, vinyl
methyl ether and the like. A water soluble polymer
prepared by copolymerizing 30 weight part or less of
acrylic ester, vinyl acetate, styrene and the like monomer
with 100 weight parts of the monomer having the formula (V)
may be optionally utilized as the water soluble polymer of
the component (A).
Example of (meth)acrylic ester monomer of the component
(B) are: (meth)acrylic ester, dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate and the
like.
Still another example of the water swelling adhesive is
the adhesive described in Laid- Open Japanese Patent
Publication Showa 56-70077 which is described in the
following.
The adhesive comprises (A) a salt of a copolymer
prepared by neutralizing carboxylic acid in a copolymer
comprising 10 to 40 mole% of monomer having carboxyl group,
60 to 90 mole % of alkyl (meth)acrylate in which the alkyl
group has ~ or more carbon atoms and O to 20 mole % of
other vinyl monomer and (B) a hydrophillic compound having
the formula: RBO(R~O)~Rlo, wherein R8 is alkyl group of 1
1 5
2~213
to 4 carbon atoms, RD is alkylene group of 2 to 4 carbon
atoms, R~o is hydrogen or alkyl group or acetyl group of 1
to 4 carbon atoms and m is an integer o~ 1 to 6.
When the printing operation using the plate roll of the
invention 2 is finished and the printing plate made of
resin attached to the base plate roll is detached, water is
added to the adhesive sheet remaining on the face of the
base plate roll or the printing plate. The adhesive sheet
is swelled by water and the adhesive ability of the
adhesive sheet is lost. The adhesive sheet and adhesive
layer are removed completely with ease.
The adhesive sheet of the invention 3 is the adhesive
sheet utilized for the plate roll of invention 1. The
adhesive sheet comprises a layer of the photo curable
adhesive and a removable sheet on one or both faces of the
adhesive layer.
The adhesive sheet comprising a layer of the photo
curable adhesive and a removable sheet only on one face of
the adhesive layer can be stored in the form of roll. It
is desirable that the faces of the removable sheet have
such characteristics that a face of the removable sheet is
more easily removed from the adhesive than the other face
of the removable sheet.
When the ease of removal of the adhesive from the
16
20~2~3
removable sheet is different between the two faces of the
removable sheet, the problem that the adhesive coated
originally on one face of the removable sheet is separated
on the both faces of the removable sheet in the roll can be
surely prevented during the operation. When the adhesive
sheet is utilized, it is pulled out from the roll, the
adhesive face of the adhesive sheet is pressed to the outer
face of the base plate roll or to the inner face of the
printing plate and the removable sheet is removed from the
adhesive. The printing plate is attached to the base plate
roll by pressing it against the base plate roll and the
plate roll is prepared.
~ hen the adhesive sheet comprises a layer of the photo
curable adhesive and a removable sheet on both faces of the
adhesive layer, it is desirable that the removable sheet at
one face of the adhesive layer is more easily detached from
the adhesive than the removable sheet at the other face of
the adhesive layer by the same reason as described. When
the adhesive sheet is utilized, the removable sheet which
can be removed from the adhesive more easily is first
removed from the adhesive sheet and the adhesive sheet is
pressed to the outer face of the base plate roll or to the
inner face of the printing plate and the remaining
removable sheet is removed from the adhesive. The printing
20~213
plate is attached to the base plate roll by pressing it
against the plate roll and the plate roll is prepared.
When the operation of printing is ~inished by using the
adhesive sheet of invention 3, the plate roll attached with
the printing plate made of resin is irradiated by, for
example, ultraviolet light for 20 to 30 seconds from the
surface of the printing plate made of resin. The photo
curable adhesive on the inner face of the printing plate is
cured by the irradiation and loses adhesive ability. Thus,
the printing plate is easily detached from the plate roll
by hand. Remaining adhesive on the faces are removed
easily.
The adhesive sheet of the invention 4 comprises a
supporting sheet and two layers of adhesive coated on both
faces of the supporting sheet and at least one of the two
layers of adhesive comprises the photo curable adhesive.
The adhesive sheet can be stored by attaching a removable
sheet on one or both faces of the adhesive sheet.
The supporting sheet is not particularly limited.
~xamples of the supporting sheet are films of polyethylene
terephthalate, nylon, polypropylene, polycarbonate and the
like other materials. When ultraviolet light, visible
light and infrared light are utilized for irradiation,
films having higher transparency is preferable so that the
1 8
2 0 !~ 0 2 1 3
light transmission is easier.
It is also preferable that the surface of the
supporting sheet is activated by corona discharge or by
like other methods to enhance the affinitY of the adhesive
and the surface.
When the adhesive sheet of the invention 4 having a
removable sheet on one face of the sheet is utilized, the
adhesive sheet is attached to the outer face of the plate
roll or to the inner face of the printing roll by the face
on which the adhesive is exposed. The removable sheet is
removed and the printing plate is attached to the base
plate roll by pressing to the base plate roll. ~t is
desirable that the adhesive layer of photo curable adhesive
is placed to the face of the base plate roll.
~ hen the printing plate is attached to the base plate
roll by utilizing the adhesive sheet of the invention 4
havirlg photo curable adhesive on one face and conventional
adhesive on the other face and the adhesive layer of the
photo curable adhesive is placed to the face of the base
plate roll, the adhesive on the snrface of the base plate
roll is cured by irradiation of ultraviolet light and the
printing plate can be detached from the base plate roll
while the adhesive sheet is still attached to the printing
late.
l 9
2~ 2~3
Printing plates made of resin are often disposcd after
the use. The adhesive sheet of the invention ~ having
photo curable sheet only on one face is suitable for easy
disposal because the adhesive sheet need not be removed.
When a printing plate made of resin is used again after
it is utilized for printing, the adhesive sheet of the
invention 4 having photo curable adhesive on the both faces
is suitable for use.
The adhesive sheet of the invention 5 is utilized for
the plate roll of the invention 2 and comprises a layer of
water swelling adhesive and a removable sheet attached on
one or both faces of the layer of the adhesive.
~ hen the removable sheet is attached only on one face
of the adhesive layer, the adhesive sheet can be stored in
the form of roll. It is desirable that the faces of the
removable sheet have such characteristics that a face of
the removable sheet is more easily removed from the
adhesive than the other face of the removable sheet.
When the ease of removal of the adhesive from the
removable sheet is different between the two faces of the
removable sheet, the problem that the adhesive coated
originally on one face of the removable sheet is separated
on the both faces of the removable sheet in the roll can be
surely prevented during the operation. When the adhesive
2 0
20~ 213
sheet is utilized, it is pulled out from the roll, the
adhesive face of the adhesive sheet is pressed to the outer
face of the base plate roll or to the inner face of the
printing plate and the removable sheet is removed from the
adhesive. The printing plate is attached to the base plate
roll by pressing it against the base plate roll and the
plate roll is prepared.
When the adhesive sheet comprises a layer of the water
swelling adhesive and a removable sheet on both faces of
the adhesive layer, it is desirable that the removable
sheet at one face of the adhesive layer is more easily
detached from the adhesive than the removable sheet at the
other face of the adhesive layer by the same reason as
described. ~hen the adhesive sheet is utilized, the
removable sheet which can be removed from the adhesive more
easily is first removed from the adhesive sheet and the
adhesive sheet is pressed to the outer face of the base
plate roll or to the inner face of the printing plate and
the remaining removable sheet is removed from the adhesive.
The printing plate is attached to the base plate roll by
pressing it against the plate roll and the plate roll is
prepared.
When the operation of printing is finished by using the
adhesive sheet of the invention 5, the printing plate made
20~1~213
of resin is detached from the base plate roll by using a
conventional method. Adhesive remaining on the surfaces of
the base plate roll and printing plate made of resin is
treated with water. The adhesive is swelled by water and
loses adhesive ability and can be removed very easlly by
wiping with cloth or the like.
The adhesive sheet of the invention 6 comprises a
supporting sheet and two water swelling adhesive layers
coated on both faces of the supporting sheet. As the
supporting sheet, a porous sheet is preferred because water
penetrates easily in the sheet.
When the adhesive sheet of the invention 4 having the
photo curable adhesive only on one face is coated with the
water swelling adhesive on the other face, the adhesive
sheet formed corresponds to the adhesive sheet of the
invention 7. The plate roll is prepared by utilizing the
adhesive sheet in the same way as in the invention ~.
The plate roll attached with the printing plate by
utilizing the adhesive sheet of the invention 7 through the
photo curable adhesive on the outer face of the base plate
roll and the water swelling adhesive on the inner face of
the printing plate is, after finishing the operation of
printing, irradiated with ultraviolet light and the
printing plate is removed from the face of the base plate
2 2
2 V ~
roll while the adhesive sheet is still attached to the
printing plate.
~ hen the printing plate is dipped into water, the
adhesive is swelled and the adhesive sheet is removed
spontaneously from the printing plate. The remaining
printing plate can be utilized again after drying.
When the base plate roll is attached with the printing
plate through the water swelling adhesive on the outer face
of the base plate `0l 1 and the photo curable adhesive on
the inner face of the printing plate, the printing sheet
remains on the surface of the base plate roll and can be
removed by swelling with water.
The former method is preferable because the printing
plate is quickly detached from the base plate roll.
The invention will be understood more readily with
reference to the following examples; however these examples
are intended to illustrate the invention and are not to be
construed to limit the scope of the invention.
~xample 1
Polyethylene terephthalate film of 50~ thickness
activated by corona discharge on both faces was used as the
supporting sheet for a double faced tape.
A removable sheet of polyethylene terephthalate film of
2~2~3
38~ thickness coated with silicone on one face w~s coated
with a photo curable adhesive to 15~ thickness by a knife
coater on the face coated with silicone. The adhesive was
an acrylic adhesive comprising 40 weight % of
trimethylolpropane (me~h)acrylate and 5 weight ~ of benzoin
was further added as the photo sensitizer.
The removable sheet coated with the photo curable
adhesive was laminated to the both faces of the supporting
sheet and a double face adhesive sheet was prepared.
~ ne of the removable sheets on the adhesive sheet was
removed and the adhesive sheet was pressed to a printing
plate made of resin (Torayleaf~, a product of Toray Co.,
~td., 1 mm thickness). The other removable sheet was
removed and the printing plate was attached to a stainless
steel base plate roll by using the double face adhesive
sheet.
After standing for 24 hours, the plate roll was
irradiated with ultraviolet light by a 35 mW/cm2
ultraviolet lamp for 20 seconds over the printing plate
made of resin. Total dose of ultraviolet light irradiated
was 700 mJ/cmZ.
After the irradiation, the printing plate made of resin
was easily detached by fingers. The adhesive sheet
remained attached to the face of the printing plate when
24
20~213
the printing plate was detached from the base plate roll
and was removed from the printing plate easily by fingers.
The samc adhesive sheet as the above was laminated to
the same printing plate as the above and used for adhesion
test without attaching to the base plate roll. After
standing for 24 hours, the adhesive strength was 1700 g/25
mm width. Then, ultraviolet light was irradiated to the
outer face of the printing plate made of resin in the same
condition as the above. Ten minutes after the irradiation,
the adhesive strength decreased to 90 g/25 mm width.
Example 2
A removable sheet coated to the thickness of 50~ with an
acrylic water swelling adhesive which comprised a copolymer
of ethyl acrylate, vinyl acetate and methacrylic acid and
polyethylene glycol lauryl ether and was crosslinked by
zinc acetate in the presence of potassium hydroxide was
utilized in place of one of the two removable sheets coated
with adhesive utilized in Example 1. A porous sheet of
polyethylene terephthalate treated by corona discharge was
utilized as the supporting sheet. A printing plate was
attached to a base plate roll by the same method as in
~xample 1.
After standing for 24 hours, ultraviolet light was
2 5
20~2~ 3
irradiated by the same method as in Example 1. The
printing plate was detached from the base plate roll easily
by fingers.
When the printing plate was detached from the base
plate roll, the adhesive sheet was firmly attached to the
inner face of the printing plate. After dipping the
printing plate in water for 3 hours, the adhesive sheet was
removed from the printing plate easily by fingers.
While the invention has been particularly shown and
described with reference to preferred embodiments threrof,
it will be understood by those skilled in the art that the
foregoing and other changes in form and details can be made
therein without departing from the spirit and scope of the
invention.
To summarize the advantages obtained by the invention,
the plate roll attached with the printing plate made of
resin according to the invention has advantages that the
printing plate attached is easily detached, the adhesive
sheet and remaining adhesive are easily removed after the
operation of printing is finished and thus efficiency of
the operation of printing is enhanced.
2 6
