Note: Descriptions are shown in the official language in which they were submitted.
- 1 1337223
3-16439/+
Photopolymerizable compositions of matter
The invention relates to photopolymerizable compositions of matter
containing a-aminoacetophenone derivatives as photoinitiators and
thioxanthone derivatives as photosensitizers, to the use of these
compositions of matter as adhesives which cure within the UV and/or
visible range and to a process for bonding surfaces.
Photopolymerizable adhesives of various compositions are known. The
use of photopolymerizable adhesives is steadily increasing in impor-
tance, since these adhesives, compared with heat-curable adhesives,
make possible not only savings in energy but also a more rapid produc-
tion of adhesive bonds. One potential field of use for photopolymeri-
zable adhesives is in the bonding of materials which are transparent
to UV and/or visible radiation, for example various plastic films, to
opaque materials, such as cardboard, metals, etc. Adhesive bonds of
this type are made, for example, in the production of blister pack-
ages, identity cards or credit cards. At the present time, however,
the majority of these bonds are still produced with the use of heat-
curable adhesives.
Swiss Patent Specification 560,594 describes a process for the pre-
paration of composite materials, for example packages, using photo-
curable adhesives, for bonding a material transparent to light to a
material opaque to light. The adhesives used preferably contain an
unsaturated polyester and an acrylate ester and can also contain a
polymerization accelerator, for example an organic cobalt salt or a
tertiary amine, and a photosensitizer, for example propiophenone or
naphthalene derivatives.
13~722~
- 21489-7405
Swiss Patent Specification 655,476 describes a process for bonding
blister packages using an adhesive which can be cured by means of UV
radiation, but does not contain any information on the composition of
the adhesive.
Blister packages and also identity cards and credit cards [cf. Kunst-
stoffe 77, 880 (1987)] are usually prepared from PVC sheeting, but
this material is being increasingly replaced, i.a. for reasons of en-
vironmental protection, by other types of polymer, for example poly-
styrene, polyacrylonitrile, polyethylene terephthalate, polyamides,
polyolefines or polycarbonates. Whereas PVC only absorbs UV radiation
in the relatively short-wave range (60~ transmission at approx.
300 nm), the other polymers mentioned are in some cases also opaque to
relatively long-wave UV radiation. One consequence of this is that,
when using sheeting materials of this type, commercially available UV
adhesives exhibit a considerable retardation in the polymerization
rate and also shortcomings in adhesion. These problems can be solved
by using certain compositions of matter containing suitable photo-
initiators and photosensitizers.
The present invention relates to compositions of matter containing(a)
an oligomeric (meth)acrylate, (b) a monomeric (meth)acrylate, (c) a
flexibilizer, (d) a silane adhesion promoter, (e) an a-aminoaceto-
phenone derivative as photoinitiator and (f) a thioxanthone derivative
as photosensitizer, and wherein the composition of matter comprises 10 to 60
parts by weight of the component (a), 10 to 50 parts by weight of the
component (b), 5 to 40 parts by weight of the component (c), 0.1 to 10
parts by weight of the component (d), 0.5 to 10 parts by weight of the
component (e) and 0.01 to 5 parts by weight of the component (f), the
total amount of the components (a) to (f) and any further additives
adding up to 100 parts by weight.
The invention also relates to the use of the compositions of matter of
the type defined as adhesives which photocure in the UV range and/or
in the visible range and to a process for bonding two or more sub-
strates at least one of which is a substrate transparent to UV and/or
visible light, ~i) the composition of matter according to the inven-
tion being applied to at least one of the surfaces to be bonded,
(ii) the surfaces to be bonded being brought into contact with one
1337223
21489-7405
-- 3 --
another, ( iii) the arrangement be~ng compressed, if necessary, and
(iv) the bond being cured by means of irradiation through the
material transparent to radiation. The process according to the
invention is particularly suitable for the production of blister
packages, identity cards and credit cards.
The preferred amounts of the components (a) to (f) in the compositions
of matter according to the invention are as follows:
preferably 15 to 40 parts by weight of the component (a);
preferably 20 to 40 parts by weight of- the componént (b);
preferably 1(3 to 3() parts by weight of the component (c);
preferably 0.5 to 5 parts by weight of the component (d);
preferably 1 to 6 parts by weight of the component (e) and
preferably 0.1 to 3 parts by weight of the component ( f), the total
amount of the components (a) to (f) and any possible further additives
adding up to 100 parts by weight.
The components (a) and (b), according to the invention, i.e. the
oligomeric and monomeric (meth)acrylates, respectively, are esters of
acrylic or methacrylic acid.
The oligomeric acrylate or methacrylate (a) preferably contains at
least one, in particular at least two, groups of the formula I
CHz~--C0~ (I)
in which R is hydrogen or methyl, and is a polyether-acrylate, a poly-
ester-acrylate, a polyester-urethane-acrylate, an epoxide-acrylate
and, in particular, a urethane-acrylate.
Suitable compounds of the type mentioned are known to those skilled in
the art and can be prepared in a known manner. They are descri~3ed,
for example, in US Patents 3,380,831, 3,297,745, 4,129,488 and
3,586,5~6 to 3,586,530. Products of this type are also available com-
mercially. Urethane-acrylates are available, for example, under the
name EBECRYL6~) (UCB, Belgium) or Uvithane~ (Morton Thiokol, USA).
They are prepared, for example, by masking prepolymers having isocya-
nate end groups with hydroxyalkyl acrylates. In general, the molecu-
lar weight of oligomers of this type is within the range from 500 to
5000, in partic~llar 1000 to 2000, but products of lower molecular
weights and also of molecular weights up to about 10,000 are also used.
B
~ 4 ~ 133~223
The preferred monomeric acrylates or methacrylates (b) contain at
least one group of the formula I and are derived from aliphatic,
cycloaliphatic, alicycloaliphatic, araliphatic or heterocyclic-
aliphatic monohydric or polyhydric alcohols; from hydroxycarboxylic
acids; from hydroxyalkylamines or from hydroxyalkyl nitriles.
Alkyl acrylates or methacrylates, hydroxyalkylacrylates or methacry-
lates, or, in particular, cycloalkyl acrylates or methacrylates are
particularly preferred as the component (b).
In general, acrylate esters are preferred to methacrylates as compo-
nents (a) and (b) according to the invention.
The monomeric (meth)acrylates (b) can contain one or more double
bonds. The following are examples of suitable monomeric compounds:
methyl, ethyl, n-propyl, n-butyl, isobutyl, n-hexyl, 2-ethylhexyl,
n-octyl, n-decyl and n-dodecyl acrylate and methacrylate, 2-hydroxy-
ethyl, 2-hydroxypropyl and 3-hydroxypropyl acrylate and methacrylate,
2-methoxyethyl, 2-ethoxyethyl, 2-ethoxypropyl and 3-ethoxypropyl
acrylate and methacrylate, allyl acrylate and methacrylate, glycidyl
acrylate and methacrylate, cyclopentyl and cyclohexyl acrylate and
methacrylate, phenyl acrylate and methacrylate, ethylene glycol di-
acrylate, ethylene glycol dimethacrylate, diethylene glycol diacryl-
ate, diethylene glycol dimethacrylate, triethylene glycol diacrylate,
triethylene glycol dimethacrylate, tetraethylene glycol diacrylate,
tetraethylene glycol dimethacrylate, l,1,1-trimethylolethane triacryl-
ate, l,l,l-trimethylolethane trimethacrylate, l,l,l-trimethylolpropane
triacrylate, l,l,l-trimethylolpropane trimethacrylate, glycerol tri-
acrylate, glycerol trimethacrylate, pentaerythritol diacrylate, pen-
taerythritol dimethacrylate, pentaerythritol triacrylate, pentaery-
thritol trimethacrylate, pentaerythritol tetraacrylate, pentaery-
thritol tetramethacrylate, butane-1,3-diol diacrylate, butane-1,3-diol
dimethacrylate, butane-1,4-diol diacrylate, butane-1,4-diol dimeth-
acrylate, hexane-1,6-diol diacrylate, hexane-1,6-diol dimethacrylate,
propane-1,3-diol diacrylate, propane-1,3-diol dimethacrylate, octane-
1,8-dioldiacrylate, octane-1,8-diol dimethacrylate, dodecane-1,12-diol
diacrylate, dodecane-1,12-diol dimethacrylate, tetrahydrofurfuryl
~ _ 5 _ 1 3 3 7223
acrylate and methacrylate, isobornyl acrylate and meth-
acrylate and dicyclopentenyloxyethyl acrylate and methacrylate.
The monounsaturated (meth)acrylates act as reactive diluents. If de-
sired, however, the compositions of matter according to the invention
can also contain further reactive diluents without (meth)acrylate
groups, in particular l-vinyl-2-pyrrolidone.
The amount of reactive diluent which can be used in addition is suit-
ably within the range from 0 to 30, in particular 10 to 20, parts by
weight, relative to the amounts defined initially of the components (a)
to (f).
The polymerizable monomers or mixtures of these monomers must not be
gaseous at room temperature; they should therefore be liquid, solid,
semi-solid or pasty.
The compositions of matter according to the invention contain a flexi-
bilizer as the component (c). This can be a thermoplast, a thermo-
plastic rubber or an elastomer. The addition of components of this
type in order to increase the adhesive power of the mixture is known
per se. As a rule, polymers of this type must carry polar or func-
tional groups. These groups can be present as end groups and/or can
be incorporated in the skeleton of the molecule.
The thermoplast, thermoplastic rubber or elastomer is preferably se-
lected from the group consisting of polyacetal, polyacrylate, poly-
methacrylate, polystyrene, polyamide, polyurethane, polyvinyl chlor-
ide, polyester (saturated or unsaturated), polyvinyl acetate, poly-
vinyl alcohol, polyvinylpyrrolidone, cellulose ester, polybutadiene,
polyisoprene or copolymers formed from styrene and acrylate or from
styrene and methacrylate, from styrene and butadiene or from styrene
and isoprene or terpolymers formed from styrene, butadiene and acrylo-
nitrile.
Preferred flexibilizers are elastomers or thermoplastic rubbers, in
particular polybutadienes, polyisoprenes, copolymers formed from
1337223
-- 6 --
styrene and acrylates or from styrene and methacrylates,from styrene
and butadiene, from styrene and isoprene or from butadiene and
acrylonitrile or terpolymers formed from styrene, butadiene and
acrylonitrile.
Nitrile rubbers are particularly preferred, for example polymers of
the KRNYAC~)type made by Polysar, polybutadiene/acrylonitrile polymers
terminated by functional and/or polar groups, for example polymers of
the HYCAR~9 type made by Goodrich, particularly the vinyl-terminated
types of these, or modified 1,2-polybutadienes, for example polymers
of the NISS ~ PB type made by Nippon Soda, particularly the urethane-
modified, maleic acid-modified, hydroxyl-modified or carboxyl-modified
types.
It is very particularly preferable for the flexibilizer (c) to contain
vinyl-terminated groups and to be, in particular, a vinyl-terminated
butadiene/acrylonitrile polymer.
A large number of silane adhesion promoters are known to those skilled
in the art. The use of compounds of this type in adhesives is des-
cribed, for example, by G. Habenicht, "Kleben" ("Adhesive Bonding"),
pages 70-73, Springer Verlag, Berlin 1986.
Preferred adhesion promoters (d) are compounds of the formula II
R10
R10/ (II)
in which the R1S independently of one another are a C1-C4alkyl group
or a C3-cloalkoxyalkyl group, R2 is a direct bond or a C2-C6alkylene
group and X is a reactive radical selected from the groups comprising
CH2=CH-, CH2=CHfl -, CH2=C - ~-, HS-, H2~-, H2NCH2CH2NH-, HO-,
C~2~CHCH20- and \ /
1337223
-- 7 --
Compounds of this type are available on the market, for example from
Union Carbide USA. Particularly preferred adhesion promoters are com-
pounds containing a glycidyloxy group, in particular Y-glycidyloxypro-
pyltrimethoxysilane. It is also possible to use silanes of the type
described in German Offenlegungsschrift 2,934,550, containing imide
groups.
cl-Aminoacetophenone derivatives are used as the photoinitiator (e) in
the compositions of matter according to the invention. These com-
pounds are known from EP-A-3,002 as photoinitiators for ethylenically
unsaturated compounds. Compounds which contain, in the 4-position of
the phenyl radical, a substituent containing sulfur, oxygen or nitro-
gen are described in EP-A 88,050, EP-A 117,233 and EP-A 138,754 as
photoinitiators for pigmented, photocurable systems, for example for
UV-curable printing inks.
Preferred photoinitiators (e) are compounds of the formula III
Ar--1~--~--N~ (I II)
in which Ar is a C6-C14aryl group which is unsubstituted or substituted
by one or more of the radicals halogen, hydroxyl, Cl-C4alkyl, Cl-C4-
alkoxy, Cl-C4alkylthio, Cl-C4alkylamino, Cl-C4dialkylamino or N-Morpho-
lino R3 and R4 independently of one another are hydrogen, Cl-C8alkyl,
C5-C6cycloalkyl or c7-c9phenylalkyl and R5 and R6 independently of one
another are hydrogen or Cl-Cgalkyl~ Cs-C6cycloalkyl or C7-Cgphenyl-
alkyl, each of which is unsubstituted or substituted by Cl-C4alkoxy
groups, or R5 and R6 together are C3-c7alkylene which can be inter-
rupted by ~-, -S- or -N(R7)-, and R7 is hydrogen or Cl-C4alkyl.
Compounds of the formula III which are particularly preferred are
those in which Ar is p-N-morpholinophenyl, p-Cl-C4alkoxyphenyl or
p-Cl-C4alkylthiophenyl~ in particular p-methoxyphenyl of p-methylthio-
phenyl, R3 and R4 independently of one another are C1-C4alkyl or
benzyl and R5 and R6 are each methyl or, together wi th the nitrogen
atom to which they are attached, are an N-morpholino radical.
8 1337223
The following are examples of suitable photoinitiators:
CS ~ 0 0~
H3CO--~ \o H3CS~ N\ /0
0/ ~ -N(CH2CH20CH3)2 (H3C)zN~ -N(CH3)2
,_. .=. H3 H3
The compositions of matter according to the invention contain thioxan-
thone derivatives as photosensitizers (f). Examples of suitable thio-
xanthone derivatives are the substituted thioxanthones described in
German Offenlegungsschrift 2,811,755, German Offenlegungsschrift
3,018,891, EP-A 33,720 and EP-A 167,489. Preferred thioxanthones are
those which are substituted by one or more halogen atoms or by one or
more Cl-C12alkylcarbonyl or Cl-C12alkoxycarbonyl groups.
Thioxanthone photosensitizers are also available, for example, under
the name Quantacure~(Ward-Blenkinsop, Middlesex, GB) or Kayacure~
(Nippon Kayaku, Japan).
The following are examples of suitable thioxanthone derivatives: 2-
isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone,
2,4-diethylthioxanthone, 2-dodecylthioxanthone, l-methoxycarbonylthio-
xanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)-
thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methyl-
thioxanthone, l-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chloro-
thioxanthone, l-ethoxycarbonyl-3-ethoxythioxanthone, l-ethoxycarbonyl-
3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone,
3,4-di-[2-(2-methoxyethoxy)ethoxycarbonyl]-thioxanthone, l-ethoxycar-
bonyl-3-(1-methyl-1-morpholinoethyl)-thioxanthone, 2-methyl-6-ethoxy-
carbonylthioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-
methyl-6-(1,1-dimethoxybenzyl)-thioxanthone, 2-morpholinomethylthio-
xanthone and 2-methyl-6-morpholinomethylthioxanthone.
9 133722~
Mixtures of different components (a) to (f) can also be employed in
each case in the compositions of matter according to the invention.
As further customary additives, the mixtures according to the inven-
tion can also contain plasticizers, reinforcing agents, for example
glass fibres, boron fibres, mineral silicates, powdered quartz, hy-
drated aluminium oxide or aluminium powder platelets, and also pig-
ments and dyes, for example titanium dioxide, thixotropic agents, flow
control agents, such as silicones, waxes and stearates, antioxidants
and light stabilizers, particularly of the sterically hindered amines
(HALS), type.
The compositions of matter according to the invention are particularly
suitable for use as photocurable adhesives. As a result of using the
special photoinitiator/photosensitizer combination, curing by means of
radiation within the relatively long-wave UV range and/or within the
visible range of the spectrum and also in daylight (i.e. without an
artificial source of light) is also possible, so that materials which
absorb UV radiation, for example various plastics, and inorganic
glasses can be bonded within a short time.
The application of the adhesive composition of matter is effected in
a manner known per se. The layer thickness of the adhesive film here
is, in general, not more than 500 ~m, preferably 40 to 120 ~m. If it
is advantageous, however, it is also possible to cure substantially
thicker layers by irradiation.
Before being coated with the adhesive composition of matter, the
surfaces to be bonded can, if it is advantageous, be degreased and
roughened.
When the coated surfaces have been joined together, they are, if app-
ropriate, compressed or clamped and are cured by means of irradiation
through the material, which is at least partly transparent in the UV
range. In general, curing is effected within about 0.1 to 30 seconds,
depending on the light source, the material to be bonded and the
adhesive used.
1337223
-- 10 --
A large number of very different types of light sources are used for
irradiating the adhesive bonds. Both point sources and sheet-like
radiating systems (lamp carpets) are suitable. The following are
examples: carbon arc lamps, xenon arc lamps, mercury vapour lamps, if
appropriate doped with metal halides (metal halogen lamps), fluore-
scent lamps, argon incandescent lamps, electronic flash lamps and
photographic flood-light lamps. As mentioned, curing can also be
carried out in daylight.
The distance between the source of radiation and the composition of
matter according to the invention can vary, depending on the end use
and the source and strength of the radiation, for example from ~1 cm
to 150 cm, preferably from 3 cm to 30 cm. It will readily be under-
stood that, when curing in daylight, the source of radiation is, of
course, at a greater distance.
Surfaces suitable for bonding are the surfaces of metals, such as
steel, aluminium and its alloys, for example with magnesium or sili-
con, copper and its alloys, so-called zincro metal (a zincchromium
alloy), polar polymeric materials, such as polyamides, polyurethanes,
polyesters, glass fibre-reinforced plastics, wood, glass, ceramics
and paper and surfaces which have been finished with coatings. The
adhesive can also be used for bonding two materials of different
types, for example cardboard or metals to coating films. The only
requirement is that at least one of the materials shall be at least
partly transparent to UV or visible radiation. The following are
some examples of the use of the compositions of matter according to
the invention: the production of blister packages, the bonding of
plastics films to identity cards, credit cards or cheque cards, the
bonding of incandescent bulbs (light bulbs), the bonding of optical
components, such as lenses or light guides (optical bonding), and the
like.
Preparation of the compositions of matter
The compositions used in the illustrative embodiments are prepared as
follows: the components are in each case mixed together in a
dissolver and are homogenized for not more than 15 minutes at 50 to
60C-
1337223
11 --
Example 1 24 parts by weight of an aliphatic urethane-acrylate
(EBECRYL5~ 270 made by UCB, Belgium), 35 parts by weight of isobornyl
acrylate, 20 parts by weight of 1-vinyl-2-pyrrolidone, 20 parts by
weight of a vinyl-terminated butadiene/acrylonitrile polymer (Hyca
VTBNX 1300X23 made by BF Goodrich, USA), 1 part by weight of Y-
glycidyloxypropyltrimethoxysilane (Union Carbide Corp., USA), 3 parts
by weight of a photoinitiator of the formula
H3CS~ /0
and 0.25 part by weight of 2,4-diethylthioxanthone.
The adhesion of various types of plastics sheeting to white cardboard
is determined by applying an adhesive film of the composition 50 to
100 ~m thick to the sheeting by means of a doctor-knife, and placing
the cardboard on this. After the test specimen has been turned
round, it is weighted down with a sheet of window glass 8 mm thick.
Curing is effected by irradiating the samples through the sheet of
glass by means of an 80 W/cm high-pressure mercury vapour lamp in a
Minicure-test apparatus at a distance of 5 to 7 cm. In the course of
this, the minimum exposure time required to reach satisfactory
adhesion is determined by varying the transport speed. The adhesion
is assessed as satisfactory if it is no longer possible to detach the
sheeting from the cardboard without causing partial damage to the
cardboard.
Irradiation time Sheet material
(seconds) PVC (0.35 mm) Polystyrene (0.4 mm)
2.10 very good very good
1.05 very good good
0.50 very good satisfactory
0.20 very good satisfactory
- 1337223
- 12 -
Example 2 Example 1 is repeated, except that the composition
contains 2-isopropylthioxanthone instead of Z,4-diethylthioxanthone.
The adhesion of various types of sheeting to cardboard printed in
blue is determined as described in Example 1.
Sheet material Transport speed Irradiation time
(m/minute) (seconds)
PVC (0.35 mm) 60 0.35
PVC (UV-stabilized, 0.20 mm) 20 1.05
Polystyrene (0.30 mm) 30 0.75
Polyacrylonitrile (0.30 mm) 30 0.75
Polyethylene terephthalate 40 0.52
(0.40 mm)
Example 3 Example 2 is repeated. The adhesion of various types of
sheeting to cardboard printed in brown is determined as described in
Example 1.
Sheet material Irradiation time (seconds)
PVC (0.35 mm) 0.50
PVC (UV stabilized, 0.20 mm) 1.00
Polystyrene (0.30 mm) 1.00
Polyacrylonitrile (0.30 mm) 0.75
Example 4 40 parts by weight of the urethane-acrylate used in Example
1, 27 parts by weight of isobornyl acrylate, 12 parts by weight of 1-
vinyl-2-pyrrolidone, 20 parts by weight of the butadiene/acrylonitrile
polymer used in Example 1, 1 part by weight of ~-glycidyloxypropyltri-
methoxysilane, 3 parts by weight of photoinitiator used in Example 1
and 0.25 part by weight of 2-isopropylthioxanthone.
The tensile shear strength of glass/plastics bonds is determined by
applying the adhesive manually to two adjacent plastics sheets approx.
3-4 mm thick and bonding these to a sheet of window glass 8 mm thick
(overlapping area 2 x 12.5 x 25 mm). Curing is effected by irradiating
- 13 - 1337223
the sample through the glass sheet in a Minicure apparatus by means
of an 80 W/cm high-pressure mercury vapour lamp at a distance of 6 to
7 cm. The transport speed is 5 m/minute, corresponding to an expo-
sure time of 4.2 seconds. After being irradiated, the test speci-
mens are stored in the dark at room temperature for 15 minutes. The
tensile shear strength to breaking point of the test specimen is then
measured by means of a tensile testing machine (Tensometer).
Sheet material Tensile shear strength* (N/mm2)
as specified in DIN 53,283
PVC (rigid, grey) 5.5 - 6.5
Polyamide (opaque) 2.0 - 3.0
Polypropylene (rigid, grey) 1.6 - 2.0
Polycarbonate (transparent) 3.5 - 4.0
Aluminium (Anticorrodal lOOB,
1.5 mm) 5.2 - 5.9
* Values from three measurements
Example 5 This example illustrates the curing of an adhesive accord-
ing to the invention in daylight. The composition of matter described
in Example 4 is used, except that 2-methyl-6-ethoxycarbonylthioxan-
thone is employed instead of 2-isopropylthioxanthone. The tensile
shear strength of glass/aluminium bonds is determined by preparing
test specimens analogously to Example 4. Curing is effected through
the glass sheet, using daylight behind window glass and at the same
time measuring the energy of irradiation by means of a UV radiometer.
The irradiation time in this case depends greatly on the intensity
of the daylight in the particular case and is between 30 and 5000
seconds. The tensile shear strengths are shown in the table against
the irradiated energy.
- 14 - 13~7 22~
Intensity of light (W/cm2) Tensile shear strength* (N/mm2)
as specified in DIN 53,283
0.01 2.6
0.02 3.8
0.03 4.8
0.05 5.5
0.075 5.8
0.10 6.1
0.20 6.9
* Average value from three measurements
Example 6 40 parts by weight of the urethane-acrylate used in Example
1, 27 parts by weight of isobornyl acrylate, 12 parts by weight of 1-
vinyl-2-pyrrolidone, 20 parts by weight of the butadiene/acrylonitrile
polymer used in Example 1, 1 part by weight of ~glycidyloxypropyl-
trimethoxysilane, 3 parts by weight of a photoinitiator of the formula
0/ ~ N(CH3)2
\.=./
and 0.30 part by weight of 2,4-diethylthioxanthone.
The adhesion of various plastics sheeting/cardboard bonds is deter-
mined by applying an adhesive film at a layer thickness of 50-100 ~m
to yellow cardboard by means of a spiral doctor-knife. The appro-
priate plastics sheet is applied to this adhesive film and is
weighted down with a sheet of flat glass 8 mm thick.
Curing is effected by irradiating the test specimens through the sheet
of glass by means of TL05 type (Philips) fluorescent tubes at a dis-
tance of 4-6 cm. The exposure times required to effect satisfactory
adhesion (cf. EXample 1) of the plastics sheet to the cardboard are
shown in the table.
- 15 - 1337 223
Sheet material Irradiation time ( seconds)
PVC (0.35 mm) 10
PVC (UV-stabilized, 0.20 mm) 20
Polystyrene (0.30 mm) 25
Polyacrylonitrile (0.40 mm) 15
Example 7 The composition of matter described in Example 1 is used
as described in Example 6 for the production of plastics/cardboard
bonds ( yellow card-board), and the latter are tested.
Sheet materialIrradiation time (seconds)
PVC (0.35 mm) 5.0
PVC (UV-stabilized, 0.20 mm) 15.0
Polystyrene (0.30 mm) 7.5
Polyacrylonitrile (0.40 mm) 7.5
Example 8 24 parts by weight of the urethane-acrylate described in
Example 1, 35 parts by weight of isobornyl acrylate, 20 parts by weight
of l-vinyl-2-pyrrolidone, 20 parts by weight of the butadiene/acrylo-
nitrile polymer described in Example 1, 1 part by weight of Y-
glycidyloxypropyltrimethoxysilane, 3 parts by weight of the photo-
initiator described in Example 6 and 0.25 part by weight of 2-chloro-
thioxanthone.
The adhesive composition of matter is applied as described in Example
1, and the adhesion of various types of plastics sheeting to white
cardboard is tested as in Example 1.
Irradiation time Sheet material
(seconds) PVC (0.35 mm) Polystyrene (0.4 mm)
2.10 very good very good
1.05 very good good
0.50 very good satisfactory
0.20 very good satisfactory
- 133~ 223
- 16 -
Example 9 The composition of matter described in Example 1 is used,
except that 2,4-diethylthioxanthone is replaced by 2-chlorothioxan-
thone. The adhesion to cardboard printed in blue is determined by
preparing and testing test speciments as in Example 1.
Sheet material Transport speedIrradiation time
(m/minute) (seconds)
PVC (0.35 mm) 60 0.35
PVC (UV-stabilized, 0.20 mm) 20 1.05
Polystyrene (0.30 mm) 30 0.75
Polyacrylonitrile (0.30 mm) 30 0.75
Polyethylene terephthalate 40 0.52
(0.40 mm)
Example 10 The composition of matter described in Example 2 is used
in accordance with Example 4 to determine the tensile shear strength
of various glass/plastics bonds (plastics sheets 3-4 mm thick/8 mm
sheet of glass).
Sheet material Tensile shear strength (N/mm2)
as specified in DIN 53,283
ABSl (red) 5.0 - 5.8
SMC2 (white) 5.5 - 6.5
Polycarbonate (transparent) 6.5 - 7.5
Polypropylene (rigid, grey) 2.0 - 3.0
Polyamide (opaque) 3.0 - 4.0
PVC (rigid, grey) 5.5 - 6.5
Aluminium (Anticorodal lOOB, 1.5 mm) 5.3 - 6.1
1: Graft polymer of acrylonitrile and styrene on butadiene polymer
2: Glass fiber laminate prepared using a moulding material composed
of unsaturated polyester (sheet moulding compound)
Example 11 The composition of matter described in Example 2 is used
to bond transparent polycarbonate films (0.17 mm thick) which are
used, for example, in the production of identity cards. This is
effected by applying a homogeneous film of the adhesive, 70-90 ~m
thick, by means of a spiral doctor-knife to a film measuring approx.
~- - 17 - 1 3 3 7 22 3
5 x 5 cm and covering the latter, WitllOUt air inclusions, with a
second section of film measuring 5 x 5 cm, a strip of approx. 1 cm
over the whole width of the film remaining free from adhesive when the
latter is applied. The films are weighted down with a sheet of window
glass 8 mm thick and are then cured. Curing is effected by exposure
for 8 seconds to an 80 W/cm high-pressure mercury vapour lamp in a
Minicure test apparatus, at a distance of 5 to 7 cm. Even immediately
after curing, it is no longer possible to separate the bonded films by
hand.
Example 12 Example 5 is repeated, using as the adhesive the compo-
sition of matter described in Example 2. Curing is effected in day-
light (sunny weather). The exposure time and the corresponding
measurement of light intensity can be seen from the table.
Exposure timeLight intensity Tensile shear strength* (N/mm2)
(seconds) (W/cm2) as specified in DIN 53,283
0.01 2.3-2.8
150 0.05 4.2-4.8
300 0.10 5.3-5.8
600 0.20 6.0-7.0
* Values from three measurements
