Note: Descriptions are shown in the official language in which they were submitted.
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ADHESIVE THERMOPLASTIC COMPOSITIONS
The present invention relates to thermoplastic
compositions exhibiting adhesive properties, that it to
say compositions commonly called hot melts, and in
particular thermoplastic sealing agents and compositions
hereafter called hot melts.
Hot melt techniques axe extremely diversified and
range from the weakest types of glue bonding, for example
in the cardboard trade, to the most difficult types of
sealing, such as joining metal to metal, metal to glass
and glass to glass.
The question of durable and perfectly lactate
metal to metal seals, for example for certain types of
steel work, or metal to glass seals, for example for light
bulbs, and glass to glass seals, for example for double
glazing, will be dealt with below with specific reference
to double glazing, for which the criteria imposed are the
strictest.
Double glazing must satisfy two conditions of
primary importance, namely the permanent existence of a
sheet of dry air preventing internal condensation, and the
cohesion of the whole unit.
The sheet of dry air can be obtained by means of
a desiccant (silica gel, molecular sieve or the like)
located between the two panes, and of moisture barriers
set up around the edge of the double glazing The
cohesion of the whole unit can be achieved by means of
welding or glue bonding.
Welding the glass to itself or to an inserted
metal frame provides perfect leak tightness and cohesion,
but this technique has been abandoned because it is very
difficult and expensive to carry out.
glue bonding by means of polysulfides and more
rarely, with the aid of other cross linked elastomers
polymers, which are applied cold as a mixture with a
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catalyst, does not provide perfect leak tightness, which
can only be achieved by the additional application of a
hydrocarbon polymer which is perfectly hydrophobic but of
low cohesion. The cohesion of the whole unit is acquired
by virtue of the second crosslinkable polymer, but at the
expense of rather slow polymerization (up to 24 hours),
which remains dependent on the dose and the activity of
the catalyst. Briefly, crosslinkable elastomers are
suitable for industrial manufacture with specialized
means, but are hardly suitable for the work of the small
craftsman in glazing.
A more recent technique, which is mentioned in
French Patent application No. 73 140~6 (now French Patent
No, 2,185,669), is to apply hot melts, which are not
cross linked and permit immediate use. A new improvement
in this field is the coating, on three faces, of the
spacer bars forming the frame on either side of which the
two panes are placed.
The limitations of the current technique are
related to the character of sealing agents whereby they
melt when heat is applied, the sealing agents being
reversible thermoplastics; there it a certain amount of
flow when cold Rand a fortiori when hot), and,
consequently, if the units are stored under conditions
where the two panes are not supported simultaneously by
their lower edge, the unsupported pane can slide downwards
and, in the worst cases, lose the leak tightness.
The object of the present invention is to improve
the sag resistance of joints produced by means of hot
melts, and in particular the creep resistance of double
glazing, by the addition, to the conventional hot melt
compositions, of a resin which gives these hot melts
satisfactory properties in the areas of cohesion and
impermeability to water vapor.
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For this purpose, the invention relates Jo a hot
melt of otherwise conventional composition, comprising at
least one rubbery constituent and at least one resinous
constituent, whose composition includes a "special resin"
miscible with the rubbery constituent on the macroscopic
scale, this special resin including regions of high
cohesion incompatible with the rubbery constituent on the
molecular scale, and regions of low cohesion compatible
with the same rubbery constituent on the molecular scale.
This special resin imparts a better sag resistance, has
certain synergic effects and increases the modulus of this
rubbery constituent, even for small elongations.
Apart from these rubbery and resinous
constituents and the said special resin, the adhesive
thermoplastic composition according to the invention can
comprise other constituents which usually form part of the
composition of a hot melt, and in particular plasticizers,
fillers and/or stabilizers.
The hot melts according to the invention will be
described below by defining more precisely the various
constituents which they comprise or may comprise, and the
relative amounts of these constituents.
In the description given below of the
Compositions according to the invention, unless indicated
otherwise, the amounts are indicated in parts by weight
per 100 part by weight of the rubber which is one of the
constituents.
The hot melts according to top invention always
comprise a number of constituents which are divided up
I into the following categories:
- the rubbers
- the resins
- the "special rosins
depending on the relative amounts and the
particular type of the constituents falling into these
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first three categories, and depending on the particular
type of composition required, the hot melts according to
the invention can also comprise one or more of the
constituents which are divided up into the following
categories:
- plasticizers
- fillers
- stabilizers and various other constituents.
The rubber present into the hot melts of the
invention constitutes the elastomers base, the purpose of
which is to absorb shocks at low temperature and to form
the barrier to water vapor, in addition to keeping the
so-called tackifiers in dispersion, the tackifiers being
the agents which give a tacky character to the mixture
into which they are incorporated.
The specific compositions according to the
present invention contain 100 parts by weight of one or
more rubbery constituents which consist, at least in part,
of one or more "virgin" rubbery constituents chosen from
amongst solid elastomeric polymers having a molecular
weight of about 15,000 to 200,000 or 300,000 or more.
These polymers and the trade names by which they are
sometimes known include in particular, the bottle rubbers
such as isobutylene/isoprene copolymers, polyisobutylene
("Vistanex * L"), ~tyrene/butadiene polymers ("GAS" and
"Keaton * SUBS"), styrene/isoprene polymers
("Keaton* SKIS"), hydrogenated styrene/butadiene and
styrene/isoprene polymers ("Kraton*SEBS"), and the
halogenated rubbers ("Parson*").
The bottle rubber used according to the invention
can be any type of bottle rubber having a Mooney viscosity
(ML 1 + 3 at 127C) of about 30 to 80, namely an
isobutylene homopolymer or alternatively a copolymer of
* trade mark
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isobutylene with a small amount, for example about 1 to 5
mow %, of a conjugated dine or pylon such as, inter
alias butadiene, isoprene, piperylene or
2,3-dimethylbutadiene. This bottle rubber can be slightly
cross linked and consist of one of the products conforming
to U.S. Patent no. 3,674,735. Special preference is given
to bottle rubbers having a Mooney viscosity, such as
defined above, of about 50 to 60, corresponding to a
molecular weight of approximately 450,000, which have a
degree of unsaturation of about 1,5 mow % and, after
vulcanization at 150C for 40 minutes of a standardized
mixture, a modulus at 300% elongation of about 7 to 9 Ma,
an ultimate tensile strength of about 16 Ma and an
elongation at break of 450%. An example of a rubber of
this kind is Pulsar* P301~
Apart from the "virgin" rubbery constituents as
listed above by way of examples, the hot melts according
to the invention can also comprise regenerated rubbers
and/or prevulcanized rubbers.
An example of a regenerated rubber which can be
used is a rubber having an ultimate tensile strength of
8.8 1.6 Ma and an elongation at break of 525 + 40%. A
prevulcanized rubber which can be used in particular is
the rubber Killer.
As indicated above, the amount represented by all
the rubbery constituents forming part of the composition
of the hot melts according to the invention is considered
as the reference amount namely 100 parts by weight.
It is generally advantageous for at least a major
part, that is to say at least half (at least 50 parts), of
this amount of rubbery constituents to be formed of one or
more "virgin" rubbers, it being possible fox the remainder
( f rum 0 to 50 parts) to be represented by regenerated
rubbers and/or prevulcanized rubbers.
* trade mark
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The resins form the second class of functionally _
important constituents of the hot melts of the invention.
They can be chosen, in particular, from amongst the
following types:
(a) Aliphatic hydrocarbon resins and
cou~arone/indene resins which have a softening point
(ring and ball) of about 100C, of the kind described in
U.S. Patent 4,294,733, for example the resin
Escorez*(Esso) taken in amount of up to 500 parts and
preferably of about 165 parts. Another suitable resin is
Impresses).
It is generally advantageous for at least part of
the amount of resinous constituents of the hot melts
according to the invention to be represented by one or
more aliphatic hydrocarbon resins and/or one or Gore
coumarone/indene resins. It is the resins of this kind,
in particular, which constitute the tackifiers of the
composition.
(b) Aromatic resins (polymers of C8 cuts) or
terpene-phenolic resins, having a softening point (ring
and ball) of up to 200C, for example the resin Norris*
having a softening point (ring and ball) of 150C, taken
in an amount of up to 300 part and preferably of about
100 parts. Another suitable resin is the resin
Piccofyn*(Hercules).
(c) EVA resins, or ethylene/vinyl acetate
copolymers, having a melt flow index, usually called MFI,
of not more than 700 and preferably of about 25, for
example an EVA resin containing 28% of vinyl acetate and
having an MFI of 22 to 28, such as the resin Elvax*
(Dupont), taken in an amount of up to 200 parts and
preferably of about 100 parts. It is the EVA resins, in
particular, which are widely used in all adhesive
compositions for ensuring a good spread and a good
adhesion to metals.
* trade mark
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The list of resins indicated above is not
exhaustive and other resinous constituents, especially
those used in known hot melt compositions, can also form
part of the composition of the hot melts according to the
invention.
The relative amount of the resinous constituent
or constituents of the composition can vary within fairly
wide limits according to the resins used and the
particular properties which it is desired to impart to the
hot melt.
As a general rule, all the resinous constituents
incorporated into the composition will represent from 50
to 1,000 parts and advantageously from 100 to 500 parts
The third class of essential constituent of the
hot melts according to the invention is formed by the
"special resins", which will be defined below.
In the same way as the resins which Norm part of
the second class of constituents as described above, the
"special resins" obviously form part ox a very large
number of substances called "resins".
For the purpose of describing the object of the
present invention, however, it is useful to consider these
"special resins" as forming a separate class of
constituents because it is essentially the incorporation
of these "special resins" into the composition which
constitutes the naivete and the originality of the hot
melts according to the invention, compared with thy known
hot melt 5 .
It is by virtue of the incorporation of these
3 "special resins" that the hot melts according to the
invention have advantageous properties in comparison with
analogous hot melt compositions which do not comprise
these "special rosins
The "special resins" which form part of the third
class of the essential constituents of the hot melts
according to the invention are resins which incorporate
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regions of high cohesion incompatible with the rubbery
constituent on the molecular scale, but which are miscible
on the macroscopic scale.
In general, the resins which are called "special
resins" in the present specification form part of the
class of the block or multi block copolymers consisting of
elastomeric segments and rigid segments of high cohesion.
More particularly, the said elastomeric segments
consist of polyols, polyethers or polyesters and the rigid
segments of high cohesion consist of poly(tetramethylene
terephthalate), polyurethane, polyamides or copolyamides.
Examples of these block or multi block copolymers
which are commercially available are as follows
(designated by their trade name): Paybacks (AUTO) and
Pellethane (Upjohn).
It is these block copolymers which give the hot
melts of the invention their superiority over analogous
products by improving, in particular, the flow resistance
when cold and even when hot.
According to an advantageous embodiment of the
invention, these block copolymers consist of
copolyetheresteramides which are formed of the product
resulting from the copolycondensation of an ,
dicarboxylic polyamide or copolyamide having a molecular
25 weight of 300 to 15,000 and preferably of 400 to 5,000,
employed in an amount of 90 to 5% by weight, and of an
aliphatic dihydroxylated polyoxyalkylene having a
molecular weight of 100 to 6,000 and preferably of 200 to
5,000, employed in an amount of 10 to 95% by weight, the
said product having a softening point (ring and ball) of
between 80 and 210C and preferably of 100 to 200C, and a
viscosity in the molten state of 10 to 2,000 Pays at 200C.
According to one embodiment, the said
condensation product comprises 60 to 20% of the said
polyamide or copolyamide and 40 to 80% of the said Jo
-dihydroxylated polyoxyalkylene.
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Preferably, the said "special resin" is a block
polyetheresteramide formed of Cop 6.11/PPG/PTMG,
PA 12/PTMG or Cop 6.12/PPG. The abbreviations have the
following meanings:
PUG : polyoxypropylene glycol
PTMG : polyoxytetramethylene glycol
PA : polyamide
Cop : copolyamide
6, 11 or 12 : respectively, polyamide-6, 11 or 12.
More particularly, the said special resin can
consist of a block copolyetheresteramide which has a
softening point (ring and ball) of 120 to 190C and a
viscosity in the molten state of 100 to 800 Pads at 200C,
and which corresponds to the formula:
Ho - C - PA - C 0 PI - 0 - - H
_ n
o
in which:
Pi represents a rigid polyamide segment having a
25 molecular weight of approximately 500 to 2,000, and
PI represents a flexible polyether segment having
a molecular weight of approximately 1,000 to 3,000.
The amount of special resin in the composition of
the hot melts according to the invention can vary within
fairly wide limits. In general, the compositions will
comprise from 1 to 300 parts of one or more special resins
and more particularly from 10 to 150 parts. An example of
a special resin of this type is Pebax*(ATO), which is used
in an amount of up to 250 parts, preferably of 10 to 150
parts and especially of 30 to 80 parts.
* trade mark
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The fourth class of constituents which the hot
melts of the invention can comprise includes plasticizers,
which are divided into:
(a) Polyisobutylenes of low molecular weight,
namely of at most 50,000, which impart the adhesion to
glass, for example Vistanex*LM taken in an amount of up to
500 parts and preferably of 100 parts. Similar suitable
polymers are the polybutene Hyvis*(BP) and Indopol*
(Amoco).
(b) Tactic polypropylene, which are the
hydrocarbon-soluble residue from the polymerization of
propylene by the Ziegler-Natta process. A polymer of this
type makes the flow rate uniform when the hot melts are
applied. An example of these polymers is Vispol*
(Interchimica) taken in an amount of up to 250 parts and
preferably of about 40 parts. Another useful agent of
this type is Afax*(Hercules).
(c) ~aphthenic oils, the addition of which is
optional and whose purpose is to adapt the viscosity to
the characteristics of the extrusion machines. Examples
of these oils are En~rthene*(BP) and Coors). The
amount of naphthenic oil could be up to 300 parts.
The fifth class of constituents which the hot
melts of the invention can comprise includes fillers. The
purpose of these is to reinforce, to protect against
ultraviolet radiation and to absorb infrared radiation.
; The fillers can be ox organic type, such as carbon black,
for example FEZ Sterling, taken in an amount of up to 300
parts and preferably of 50 to 100 parts, or alternatively
of inorganic type, such as chalk, talc, titanium dioxide,
asbestos, fibers, clay or silica, inter alias the addition
of which is optional and can amount to ~00 parts.
The sixth class of constituents which the hot
* trade mark
;
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melts can comprise includes stabilizers and additives
making it possible Jo optimize the properties of the
product according to requirements.
The stabilizer used can be any stabilizer
commonly used for rubbers, plastics and resins, for
example Irganox*1010 (Ciba-Geigy), in an amount of up to
20 parts and preferably of 3 to 5 parts.
The glass/hot melt bond can be improved by means
of an organosilane, which may or may not be coupled with
an epoxy resin. Amongst the sullenness used there may be
mentioned those sold under the names A-172, A-186, A-187,
A-153 and A-151 (Union Carbide Corporation). These
organosilanes are used at concentrations ranging, for
example, from 0,5 to 30 parts and preferably of about 15
parts
The invention is illustrated by the specific
examples below, with reference Jo the attached drawings;
in these drawings:
Figure 1 is a simplified side view showing the
assembly of a test piece for a flow test;
Figure 2 is simplified side view showing the
assembly of a test piece for a peel strength test at 180;
Figure 3 is a simplified side view showing a test
piece for a dynamic shear test; and
foggier 4 is a simplified side view of the
arrangement for measuring the movement in a double glazing
unit.
In the examples, the useful properties of the hot
melts are measured and compared by means of the tests
described below.
1. As indicated in Figure 1, the following are
placed successively on a plane surface: galvanized steel
plate 1 (75 mm x 150 mm x 1 mm), a glass plate 2 (75 mm x
* trade mark
Jo ,.
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150 mm x 6 mm) protected by silic~ne-coated paper Jo serve
as a spacer and offset by 35 mm, and a second glass plate
3 having the same dimensions, offset by 10 mm relative to
the steel plate
20 The hot melt 4 is extruded between the steel
and glass plates. A 10 kg weight is placed on the whole
structure, which is left to cool for 30 minutes. The
surplus hot melt 4 is removed by means of heated knife
so as to give a joint of 25 mm x 75 mm x 6 mm.
3. One hour after assembly, the glass spacer is
removed, the position of the steel plate relative Jo the
glass is marked and the test piece is suspended, by means
of a hole made in the steel plate in an oven at 85 + 2C
for 1 hour, with the glass facing downwards.
4. The test piece is removed from the oven and
the slip of the glass away from the initial mark is
measured. The value is rounded off to the nearest
millimeter.
b. Peel strength at 180 on a test piece
1. us indicated in figure 2, the test pieces
are prepared by extruding the hot melt 5 into the gap made
by a silicone-treated glass plate 6 (25 mm x 150 mm x
4 mm) between a clean virgin glass plate 7 (25 mm x 150 mm
x 4 mm) and a new aluminum foil 8 (25 mm x 150 my x 0,1
mm) placed on a supporting glass plate 9 (25 mm x 150 mm x
4 mm). After extrusion, pressure is applied with the hand
and the surplus it removed to give a sealing area of 25 mm
x 50 mm. The whole structure is left to cool for about 10
minutes and the silicone-treated glass plate is removed.
I The test pieces are conditioned for 4 hours
at ambient temperature (23 + 2C) before being subjected
to aging, if appropriate.
3. After aging, the test pieces are allowed to
return to ambient temperature (60 minutes).
4. The test pieces are placed in the tensile
testing machine operating at a spend of 50 mm/minute.
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5. All the peel strength values must be
measured at ambient temperature (23 + 2C).
I The peel strength test consists in pulling
the aluminum foil off the glass plate, forming an angle of
180 by folding back the free end of the aluminum foil.
JO The value of the peel strength is equal to
the average of 3 values measured for each conditioning
operation.
8. If breaking occurs, it must be stated
whether this is cohesive or adhesive. It is cohesive if
it occurs within the hot melt. It is adhesive if it
occurs at the junction between the hot melt and the
substrate and, according to the particular case, is
referred to as glass-adhesive or aluminum-adhesive.
9 The accuracy is estimated to be + 15~.
c Dynamic shear test
_
1. Using the same general conditions as for the
flow test and peel strength test, with an adapted
arrangement, test pieces such as shown in Figure 3 are
prepared, which comprise a 4 mm thick glass plate 10, a
seal 11 of 25 mm x 25 mm over a thickness of 4 mm, and
a galvanized steel plate 12.
2. After conditioning for 24 hour at ambient
25 temperature ~23 + 2C), a tensile force of 10 mm/minute is
exerted at 25C using a tensile testing machine.
; 3. The tabulated value is the average of 3
measurements.
d. Creep Test
1. Double glazing units 13 of 350 mm x 500 mm
are constructed as illustrated in Figure 4; their 4 mm
thick paps 14, 15 are separated by 12 mm wide aluminum
spacers 16 filled with a OR molecular sieve, the whole
structure being assembled by the conventional process for
extrusion of the hot melt 17.
2. The creep test is carried out in accordance
with the technique recommended by the Dutch COMMA Institute
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under the designation K24, the lower pane 15 being held
against an abutment 18 while the upper pane 14 is pulled,
along the 350 mm side, by means of a hook 19 on which a
10 kg weight 20 pulls via a wire 21 passing over a pulley
22. A comparator having a precision of 0,01 mm, which is
mounted at 23 and whose pointer on the glass plate under
tension, makes it possible to measure the movements as a
function of time.
The invention is illustrated further, without
being limited, by the examples which follow.
To carry out the examples, a number of hot melts,
whose compositions are given in Table I, are prepared.
Lo
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T A B L E
-
jot melts
1 2 3 4 - 5 6 7 8 _
Bottle rubber 74 74 74 74 7474 74 74 7
Regenerated bottle
Vredestein POOR 26 26 26 26 26 26 2$ 26 26
Hydrocarbon resin
Esquires 1304 122 122 122 122 122 122 122 122 122
Terpene-phenolic
Norris 2150 74 74 74 7474 74 74 _ 74
Block c~poly-
etheresteramide _ 20 4488 44 44 ~44 44 44
Paybacks Hal
15 ~thylene/vinyl .
acetate copolymer
I 74 74 74 74 _ 37 _ 74 74
Ethylene/vinyl
acetate copolymer _ _ _ _ 74 37 _ _ _
I Low molecular
weight
polyisobutylene 74 74 7474 74 74 74 74 74
Vistanex IT
Tactic
polypropylene 41 41 4141 41 41 41 41
Vispol 3000
Carbon black 74 74 74 7474 '74 74 74 74
Antioxidant 4 4 4 4 4 4 4 4 4
Organosilane
A-172*** _ _ _ _ _ _ _ 11
_ _ _ _ _ _
* Elvax~ MFI = 25
I* Elvax, MFI - Owe
*** A-172 : vinyltrimethoxyethoxysilane
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EXAMPLE 1.-
Influence of the proportion of block copolyetheresteramide
The sag test on a test piece (or static shear),
the peel strength test at 180 and the hardness test
(Shore A are carried out on hot melts 1, 2, 3 and 4.
The results collated in table II demonstrate that
the copolyetheresteramide Paybacks (hot melts 2, 3 and 4) is
essential and has an effective action even at low
concentration, the best results being obtained with the
hot melts comprising at least 44 parts of Paybacks.
TABLE II
-
_._ ._
Hot melt Sag at 85C Peel strength Hardness
over 1 Hart 180 (Shore A)
(mm) (N/cm)
, . _ . .. .__
1 45 80 52
2 10 118 47
3 4 90 42
_ _ 88 __
EXAMPLE 2.-
Influence of the e-thylene/vin acetate copolymers.
The same tests as in Example 1 are carried out on
hot melts in which the proportion of ethylene/vinyl
acetate copolymer varies.
The results collated in Table III show that these
copolymers are necessary (hot melts 5, 6 and 3) for a good
sag resistance, the best adhesion being imparted by an EVA
copolymer having a medium MFI (hot melt 3).
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TABLE III
. Hot melt Sag (mm) at 85C Peel strength
over 1 hour at 180 (N/cm)
. . I.. _
11 90
EXAMPLE 3.-
Influence of the terpene-phenolic resin
In addition to the flow test and the peel
strength test at 180, the viscosity in the molten state
is estimated by extrusion using a Monsanto Capillary
Remoter at 1.75C under 40 spa, with a 15:1 capillary.
The results given in Table IV show that the
terpene-phenolic resin, although lowering the sag
resistance, imparts a better viscosity in the molten state
(which is important for pumps) and a better adhesion.
TABLE IV
ought melt sag (m=) at Pee; strength Viscosity
85C over 1 at 180 ( Pot sues)
hour cam
30 3 4 go 520
8 2 _ 750
EXAMPLE 4.-
Resistance to awing
Test pieces for the peel strength test and for
the dynamic shear test, constructed using hot melts 1 and
3~3~
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3, are subjected to various aging conditions for a period
of 2 weeks.
The aging conditions are:
(1) In an oven at high humidity (65C, relative humidity
ox 95%)
(2) In a water bath at 60C
(3) In a water bath at 25C under US irradiation
(conditions described in testing technique P10 of the
"Sealed Insulating Glass Manufacturers Association"
(SIGMA), United States of America)
(4) In dry heat at 60C
(5) Under alternating 6-hour climatic cycles comprising
sty hour: from 25C to 60C, with spraying to simulate
rain during the first 30 minutes
end hour: holding at 60C
3rd hour from 60C to 25C
Thea hour: from 25C to -30C
Thea hour: holding at -30C
Thea hour: from -30C to ~25C
and including intense US irradiation for the first 3 hours
(in accordance with ASTM Standard Specification EG-PI).
For conditions 3 and 5, the transparent face is
exposed to the US radiation.
The results are collated in Table V.
;,,
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TABLE V
Accelerated aging
_ _.
aging conditions reel strength Dynamic shear
(N/cm) (N/cm )
Hot melt Hot melt
10 Initial 80 MU 2 3
High humidity 55 81 20.0 22.4
Hot Water 65 84 21.2 23.3
Water + US I 107 14.7 15.4
15 Heat 69 76 20.6 22.0
Climatic cycles 57 . .. .. 13.2 15.1
It may be concluded that the block
copolyetheresteramide has a beneficial action on
preserving the adhesion properties under various aging
conditions.
EXAMPLE 5.-
,
Effect of the block co~olyetheresteramide in heavy glazed
units O
A creep test, as described in paragraph d on page
14, it carried out on double glazing units assembled using
hot melts 1 and 3, applied in the conventional manner;
this test makes it possible to simulate to a certain
extent the loads which exist in double glazing units of
very large dimensions while at the same time working on a
convenient scale
The result given in Table VI show the creep
resistance of the glazed units under a very strong pull is
considerably improved by the bloc copolyetheresteramide.
. .
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EXAMPLE 6.-
Effect of the block copolyetheresteramide in hoe_ razed
units mounted on coated spacer bars.
The same experiments as in Example 5 are carried
out on double glazing units assembled using spacer bars
coated on 3 sides beforehand
The results given in Table VI demonstrate the
same usefulness of the block copolyetheresteramide.
TABLE VI
10 Creep of Zen unit under a 10 kg load
(Comma K24 test)
. . _ , I. .. _ _ _
Load Conventional unit Coating on 3 sides
application Hot melt Hot melt
time _ 1 3 1 3
10 minutes 0.37 0.04 0.06 0.03
24 hours 1.48 0.26 0.23 0.08
207 days 2.00 0~40 0.64 0.14
Moreover, comparison of the results achieved by
the conventional technique extrusion) and those achieved
with coating on 3 sides shows that the improvement factor
provided by a hot melt of the invention is approximately
the same in both cases.
EXAMPLE 7.-
Effect of vinyltrimethoxxethoxysilane on the resistance to
a combination of W with water
Double glazing units assembled using hot melts 3
and 9, applied in the conventional manner, are immersed in
a water bath to a depth of approximately 5 cm below the
surface.
The whole structure is exposed to ultraviolet
rays by means of 2 W lamps. Amongst these lamps, there
may be mentioned those sold under the reference "PHILLIPS
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MU 300 W B22 3 US". The penetration of water into the
double glazing unit is checked visually by the separation
which takes place between the glass and the hot melt,
caused by W bombardment. The minimum number of days of
exposure necessary, over a number of samples subjected to
this test, for the water to penetrate into the double
glazing unit is thus recorded. The results are collated
in table VII.
TABLE VII
Minimum number of days before the penetration of
water into the double razing unit.
_. _ __ Jo
Hot melt Minimum number of days
_ . ,,_._
3 I
9 120
. . ...
This shows the considerable increase in the life
of a double glazing unit subjected to the conditions
described above, when this double glazing unit is
constructed with hot melt 9 which contains an agent for
coupling with glass, in this case
vinyltrimethoxyethoxysilane, as in the example mentioned.
To summarize, the invention provides new hot
melts which have a better sag resistance, which are
suitable for application by conventional techniques
(follower-plate pump and gun) or techniques of coating on
; 3 sides, which have a lower hardness and a better impact
strength Pease of transportation and handling), which have
a better aging resistance, which have a better resistance
to the expansion of the unit under the effect of
temperature differences and which have a better resistance
.
aye elf
TV
- 23 -
to asymmetrical overloads than hot melts which do not
contain the special resin used in tune compositions of the
invention.
Of course, the invention is not limited to the
embodiments which have been described and shown by way of
non-limiting examples, and it can form the subject of
numerous modifications without exceeding the scope of the
invention.
