U.S. patent application number 14/628770 was filed with the patent office on 2015-06-11 for optical transparent dual cure adhesives composition.
The applicant listed for this patent is Henkel (China) Company Limited, Henkel lP & Holding GmbH. Invention is credited to Daoqiang Lu, Rui Zhang.
Application Number | 20150159059 14/628770 |
Document ID | / |
Family ID | 47639997 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150159059 |
Kind Code |
A1 |
Zhang; Rui ; et al. |
June 11, 2015 |
OPTICAL TRANSPARENT DUAL CURE ADHESIVES COMPOSITION
Abstract
The present invention relates to an optical transparent dual
cure adhesive, and process for preparing this dual cure adhesive,
and uses thereof. More particularly, the present invention relates
to optical transparent adhesive, which is both capable of being
UV-light cured and thermal cured, for example, it can be used for
the bonding of touch screen of an electronic device and
substrate.
Inventors: |
Zhang; Rui; (Shanghai,
CN) ; Lu; Daoqiang; (Chandler, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Henkel (China) Company Limited
Henkel lP & Holding GmbH |
Shanghai
Duesseldorf |
|
CN
DE |
|
|
Family ID: |
47639997 |
Appl. No.: |
14/628770 |
Filed: |
February 23, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14178466 |
Feb 12, 2014 |
|
|
|
14628770 |
|
|
|
|
PCT/CN2012/079869 |
Aug 9, 2012 |
|
|
|
14178466 |
|
|
|
|
Current U.S.
Class: |
522/18 ;
522/33 |
Current CPC
Class: |
C09J 133/14 20130101;
C08F 222/1065 20200201; C08F 222/1065 20200201; C09J 4/06 20130101;
C09J 175/14 20130101; C08F 220/281 20200201; C09J 109/00 20130101;
C08F 220/1811 20200201; C08F 220/1811 20200201; C09J 133/06
20130101; C08F 220/281 20200201; C08F 222/1006 20130101; C09J
175/16 20130101; C08F 220/20 20130101; C08F 220/20 20130101 |
International
Class: |
C09J 133/14 20060101
C09J133/14; C09J 109/00 20060101 C09J109/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 12, 2011 |
CN |
201110230724.1 |
Claims
1-2. (canceled)
3. An optical transparent dual cure adhesive composition, based on
the total weight of the adhesive composition, the composition
comprises: 40-90 wt % of urethane oligomer having (meth)acryloxy
group; 5-55 wt % of (meth)acrylate; 0.5-5 wt % of
UV-photoinitiator; and 0.5-5 wt % of thermal initiator.
4. The composition according to claim 3, characterized in that,
said urethane oligomer having (meth)acryloxy group has an average
degree of functionality of more than 0 and equal to or less than 3,
preferably from 0.5 to 2.5; and the glass transition temperature
T.sub.g thereof is from -80 to 0.degree. C., preferably from -60 to
0.degree. C., and the Brookfield viscosity thereof at the
temperature of 25.degree. C. preferably is from 1000 cps to 190000
cps, more preferably from 2000 cps to 150000 cps.
5. The composition according to claim 3, characterized in that,
based on the total weight of the adhesive composition, the
composition comprises 50-80 wt % of urethane oligomer having
(meth)acryloxy group, preferably 60-70 wt %; 10-50 wt % of
(meth)acrylate, preferably 20-40 wt %; 1-4 wt % of
UV-photoinitiator, preferably 2-3 wt %; 1-4 wt % of thermal
initiator, preferably 2-3 wt %.
6. The composition according to claim 3, characterized in that,
said urethane oligomer having (meth)acryloxy group has number
average molecular weight of 1000-25000 Daltons, preferably
1500-10000 Daltons.
7. An optical transparent dual cure adhesive composition, based on
the total weight of the adhesive composition, the composition
comprises: 10-80 wt % of polyisoprene having (meth)acryloxy group
or vinyl group; 10-55 wt % of (meth)acrylate; 0-50 wt % of liquid
polybutadiene, 0.5-5 wt % of UV-photoinitiator, and 0.5-5 wt % of
thermal initiator.
8. The composition according to claim characterized in that, said
polyisoprene having (meth)acryloxy group or vinyl group has an
average degree of functionality of 0.5-3, a number average
molecular weight of 10000-50000 Daltons, preferably 12000-40000
Daltons, more preferably 15000-35000 Daltons; and said liquid
polybutadiene preferably has a number average molecular weight of
1000-30000 Daltons; more preferably 1500-25000 Daltons, even more
preferably 2000-20000 Daltons, particularly preferably 3000-10000
Daltons.
9. The composition according to claim 7, characterized in that,
based on the total weight of the adhesive composition, the adhesive
composition comprises 20-70 wt % of polyisoprene having
(meth)acryloxy group or vinyl group, preferably 30-60 wt %; 10-40
wt % of liquid polybutadiene, preferably 20-35 wt %; 20-45 wt % of
(meth)acrylate, preferably 25-40 wt %; 1-4 wt % of
UV-photoinitiator, preferably 2-3 wt %; and 1-4 wt % of thermal
initiator; preferably 2-3 wt %.
10-15. (canceled)
Description
[0001] The present invention relates to an optical transparent dual
cure adhesive composition, and process for preparing the dual cure
adhesive composition, and uses thereof. More particularly, the
present invention relates to optical transparent adhesive
composition, which is both UV curable and thermal curable. For
example, it can be used for the bonding of touch screen and
substrate of an electronic device.
[0002] UV curable (abbreviated as UV cure) adhesives were reported
in the 1960s, since then considerable achievements were achieved
through an extensive research. UV cure adhesives refer to adhesives
that may cure rapidly under UV radiation. Today, UV cure adhesives
have been successfully applied in many fields of industrial
assembly, especially high-tech industries where fast assembly is
required, such as liquid crystal display (LCD) manufacturing,
cameras and other optical products manufacturing, CD manufacturing,
watch-making industry, mobile phone keypad assembly, electronic
circuit board manufacturing, electronic components manufacturing in
optoelectronic information industry such as manufacturing of the
polarized components. UV cure adhesives are also widely used in the
commodity sector, such as the manufacturing of glass furniture,
assembly of glass crafts, assembly of toys, jewelry and other
decorations, since a high and efficient productivity can thus be
achieved.
[0003] For example, Zhang Nanzhe and Xu Sulian reported
"Application of UV curable adhesive in manufacturing of LCD"
(Journal of Changchun University of Science and Technology,
2005(4)), where the application of UV curable adhesives in
manufacturing of liquid crystal displays (LCD) as well as the
technical requirements were studied.
[0004] In adhesion of touch screen components and substrate of LCD
products, for example, 3M Innovative Properties Company filed a PCT
application WO 2010/111316 A2 on Mar. 24, 2010. WO 2010/111316 A2
is directed to an optical assembly having a display panel, wherein
an adhesive layer or adhesive composition is used as the display
panel, so that the display panel is bonded to the substantially
transparent substrate. The adhesive layer comprises the reaction
product of a multifunctional (meth)acrylate oligomer, a reactive
diluent comprising a monofunctional (meth)acrylate monomer; and a
plasticizer, wherein the reaction product in the adhesive layer can
be obtained by initiating polymerization using
UV-photoinitiators.
[0005] However, in some specific application fields using the
conventional UV curable adhesives, some problems may be
encountered. For example, shadow areas may exist between the liquid
crystal panel and the substrate, that is, areas that light cannot
transmit or penetrate, UV/visible light cannot transmit through
these areas, thus the adhesives cannot be cured completely, and may
cause problems such as corrosion, aging fatigue or peeling of
unbonded edges. Generally, the shadow areas are for example the
edge areas where ink coatings exist, and etc.
[0006] Since the current commercial available UV-curable adhesive
could not meet above demands, there is a need, therefore, to
overcome such defects.
[0007] One solution to above problems is to combine adhesives
having different cure mechanisms, such as dual cure mechanism
adhesive.
[0008] As to dual cure mechanism adhesive, for example, the
following types of adhesive compositions were reported:
[0009] In U.S. Pat. No. 7,688,551 B2 (the contents thereof are
incorporated here by reference), Alexander P. Mgaya et al propose a
dual cure mechanism adhesive, wherein one cure mechanism is based
on the drying of the adhesive, which is mainly due to the
evaporation of water or other volatile substances in emulsion of
adhesive components; the other cure mechanism is UV or visible
light irradiation. This adhesive has the following components: a
water-based emulsion; (meth)acrylate functionalized monomer capable
of polymerizing or crosslinking; and at least one
UV-photoinitiator; wherein said water based emulsion is cured or
crosslinked by water evaporation/coagulation.
[0010] In addition, in U.S. Pat. No. 5,997,682 (the contents
thereof are incorporated here by reference), Daniel L. Gooman et al
propose a phase-separated dual-cure elastomeric adhesive
formulation, characterized in that the dual cure elastomeric
adhesive is E-beam cured and heat cured at relatively low
temperature; this adhesive can be used for bonding structure which
is thick or has irregular shapes, for example, the structural parts
in automobile or aeroplane having irregular shapes. This adhesive
mainly comprises: urethane acrylate oligomer sensitive to
irradiation; reactive dilute sensitive to irradiation; hydroxy
group containing compounds, such as saturated polyol; compounds
containing isocyanate functional group, such as polyisocyanate, or
urethane prepolymer. This patent proposes to rotate the structure
to be bonded, and e-beam irradiation is conducted for two or more
times and heat cure is conducted at relatively low temperature for
a certain period of long time, so as to cure the adhesive
completely.
[0011] In U.S. Pat. No. 5,696,209 (the contents thereof are
incorporated here by reference), Russell K. King et al propose dual
cure silicone adhesive composition, which is solventless dual cure
organosilicon adhesive, flowable or extrudable at room temperature.
The adhesive is first reacted by addition to cure into viscous and
sticky state; then it is condensed to cure slowly (moisture cure),
obtaining non-flowable bonded body with high bonding strength. This
patent further proposes moisture cure the addition cured product,
to form a permanent cured body.
[0012] In U.S. Pat. No. 4,605,465 (the contents thereof are
incorporated here by reference), Charles R. Morgan et al propose a
composition containing thermoplastic material which is UV curable
and also thermal curable; wherein the disclosed adhesive
composition comprises:
[0013] Liquid ethylenically unsaturated monomer, prepolymer or
polymer having the following repeating unit of:
##STR00001##
wherein thermal initiator, UV-photoinitiator, thermoplastics, for
example, vinyl resin, such as PVC, PVDC, and PS; un-polymerizable
plasticizer are used; and the thermoplastics is in the form of
dispersion in the plasticizer, wherein the use of thermoplastics
and plasticizer cause the unsaturated monomer, prepolymer or
polymer having acrylate group would not lead to a sticky surface
upon UV irradiation. Optional component includes reactive dilute,
such as monofunctional acrylate, and the heating step requires a
condition of at least 80.degree. C., preferably 80-200.degree. C.,
so as to obtain a full cure product.
[0014] However, all above dual cure adhesives could not be used to
solve the problem of the present invention, i.e., when shadows
exist between the touch screen and substrate, that is, portions or
areas that light or rays could not penetrate, adhesive can not be
cured completely, which in turn leads to problems, such as
corrosion, aging fatigue or peeling of unbonded portions.
[0015] Therefore, it is an object of the invention to provide an
optical transparent dual cure adhesive composition, which should be
able to solve all the above problems.
[0016] A first subject matter of the present invention is an
optical transparent dual cure adhesive composition, based on the
total weight of the adhesive composition, the composition
comprises:
[0017] 10-90 wt % of photo curable oligomer or polymer having
(meth)acryloxy group or vinyl group;
[0018] 5-55 wt % of (meth)acrylate;
[0019] 0-50 wt % of liquid polybutadiene;
[0020] 0.5-5 wt % of UV-photoinitiator; and
[0021] 0.5-5 wt % of thermal initiator.
[0022] In another aspect of the invention, there is provided an
optical transparent dual cure adhesive composition, based on the
total weight of the adhesive composition, the composition
comprises:
[0023] 40-90 wt % of urethane oligomer having (meth)acryloxy
group;
[0024] 5-55 wt % of (meth)acrylate;
[0025] 0.5-5 wt % of UV-photoinitiator; and
[0026] 0.5-5 wt % of thermal initiator.
[0027] In another aspect of the invention, there is provided an
optical transparent dual cure adhesive composition, based on the
total weight of the adhesive composition, the composition
comprises:
[0028] 10-80 wt % of polyisoprene having (meth)acryloxy group or
vinyl group;
[0029] 10-55 wt % of (meth)acrylate;
[0030] 0-50 wt % of liquid polybutadiene,
[0031] 0.5-5 wt % of UV-photoinitiator, and
[0032] 0.5-5 wt % of thermal initiator.
[0033] In another aspect of the invention, there is provided a
process for preparing the adhesive composition as mentioned above,
comprising the steps of:
[0034] under the condition of darkness, according to a
predetermined ratio, feeding each components of an adhesive
composition into the mixing container; conducting mixing under
agitation for a sufficient time, so as to homogenize each
components; thus obtaining the adhesive composition.
[0035] Another aspect of the invention also relates to the uses of
the adhesive composition for bonding a touch screen and substrate
of an electronic device.
[0036] The term "cure" or "curing" as used herein refers to a
change in state, condition, and/or structure in a material that is
usually, but not necessarily, induced by at least one variable,
such as time, temperature, moisture, radiation, presence and
quantity in such material of a cure catalyst or accelerator, or the
like. The terms cover partial as well as complete cure. For
purposes of the present invention, the terms mean at least
partially crosslinked, and in more preferred embodiments
substantially or fully crosslinked.
[0037] The term "dual cure" used herein refer to UV cure induced by
using UV-photoinitiator as well as thermal cure induced by using
thermal initiator, the UV light cure refers to a cure under the
irradiation of UV light for a certain period of time, and the
thermal cure refers to a cure under certain temperature for a
certain period of time.
[0038] Unless stated otherwise, all percentages, parts, ratios,
etc., are by weight.
[0039] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. In case
of conflict, the present specification, including definitions, will
control.
[0040] When an amount, concentration, or other value or parameter
is given as either a range, preferred range or a list of lower
preferable values and upper preferable values, this is to be
understood as specifically disclosing all ranges formed from any
pair of any lower range limit or preferred value and any upper
range limit or preferred value, regardless of whether ranges are
separately disclosed. Where a range of numerical values is recited
herein, unless otherwise stated, the range is intended to include
the endpoints thereof, and all integers and fractions within the
range.
[0041] Hereafter, technical terms or expressions involved in
preferred embodiments will be described, in which the embodiments
are just for the purpose of illustrating the present invention
rather than limiting the present invention.
[0042] "Photo curable oligomer or polymer having (meth)acryloxy
group or vinyl group" is a functionalized oligomer or polymer, on
the molecular chain thereof, there exists (meth)acryloxy group or
vinyl group reactive to UV light irradiation. These oligomer or
polymer is a polymer preferably having low to medium molecular
weight, for example, usually said functionalized oligomer or
polymer can have number average molecular weight of about 300 to
about 50000 Daltons, preferably 800-40000 Daltons, more preferably
1000-35000 Daltons, more preferably 3000-25000 Daltons, more
preferably 5000-20000 Daltons. Said (meth)acryloxy and/or vinyl
functional group could be located at the end(s) of the polymer
chain, or may be distributed along the polymer chain thereof. The
functional group(s) on said functionalized oligomer or polymer
chain curable by irradiation preferably have average degree of
functionality of more than 0 to less than or equal to 3, especially
from 0.5 to 2.5. Herein the term "average degree of functionality"
refers to the average number of (meth)acryloxy group or vinyl
functional group per macromolecular chain.
[0043] The non-limited but preferred examples of said oligomer or
polymer include (meth)acryloxy group functionalized urethane
oligomer, such as (meth)acryloxy group functionalized polyether
urethane, and (meth)acryloxy group functionalized polyester
urethane, polyisoprene having (meth)acryloxy group or vinyl group
and the like. These oligomer or polymer and preparation thereof are
known in art, for example, please refer to the disclosures in U.S.
Pat. Nos. 4,574,138, 4,439,600, 4,380,613, 4,309,526, their entire
contents are incorporated here by reference.
[0044] Based on the total weight of the adhesive composition, the
adhesive composition contains 10-90 wt % of said functionalized
photo curable oligomer or polymer, preferably 20-85 wt %, more
preferably 30-70 wt %.
[0045] The structure of (meth)acryloxy group is
CH.sub.2.dbd.CRC(O)O--, wherein R is H or CH.sub.3. The term
"(meth)acryloxy group" represents acryloxy, methacryloxy group or
their combination; the term "(meth)acrylic acid" represents acrylic
acid, methacrylic acid or their combination; the term "(meth)acryl"
represents acryl, methacryl or their combination, and so on,
[0046] "Urethane oligomer having (meth)acryloxy group" is a
specific and non-limited but preferred example of the photo curable
oligomer or polymer having (meth)acryloxy group or vinyl group,
which is an urethane oligomer having (meth)acryloxy group, and
sometimes it is also referred to as urethane (meth)acrylate
oligomer.
[0047] The urethane oligomer having (meth)acryloxy group preferably
has an average degree of functionality of more than 0 and equal to
or less than 3; more preferably 0.5-2.5.
[0048] The urethane oligomer having (meth)acryloxy group preferably
has a number average molecular weight of 1000-25000 Daltons, more
preferably 1500-10000 Daltons, even more preferably 2000-8000
Daltons.
[0049] The urethane oligomer having (meth)acryloxy group in
accordance with the present invention preferably has a T.sub.g of
from -80 to 0.degree. C., more preferably from -60 to 0.degree. C.
Said urethane oligomer having (meth)acryloxy group preferably has a
Brookfield viscosity of 1000 centipoise (cps) to 190000 cps, more
preferably from 2000 cps to 150000 cps; even more preferably from
5000 to 100000 cps at a temperature of 25.degree. C. at a shear
rate of 2.55 s.sup.-1, measurable by HAAKE Rotational Rheometer
with a cone plate (35 mm diameter).
[0050] Useful and preferred urethane oligomer having (meth)acryloxy
group includes commercially available products, for example, said
urethane oligomer may preferably include: urethane diacrylate
CN9018, CN9021, CN3108, CN3211, CN8004 commercially available from
Sartomer, Co., Exton, Pa.; GENOMER 4188/EHA (mixture consisting of
80 wt. % of a monoacrylate-functional polyesterbased oligomer
comprising at least one urethane bond, and 20% 2-ethylhexyl
acrylate monomers; the oligomer comprised by GENOMER 4188 has a
weight average molecular weight Mw of about 8,000), GENOMER
4188/M22 (mixture of GENOMER 4188 and GENOMER 1122 monomers),
GENOMER 4256 and GENOMER 4269/M22 (mixtures of GENOMER 4269 and
GENOMER 1122 monomers), commercially available from Rahn USA Corp.,
Aurora Ill., and etc.
[0051] Usually, the amount of said urethane oligomer having
(meth)acryloxy group used in the adhesive composition of the
present invention depends from the amounts of the other components
used for forming the adhesive composition, and the desired
properties of the adhesive composition. The adhesive composition
may include about 40-90 wt % of the urethane oligomer having
(meth)acryloxy group, preferably from about 45-85 wt %, more
preferably 50-80 wt %, more preferably 60-70 wt %.
[0052] Most specifically, examples of the urethane acrylate
oligomer used in the present invention include, for example CN9018,
CN9021, CN3108, CN3211, CN8004 from Sartomer Company, Inc.
[0053] According to the present invention, the urethane oligomer
having (meth)acryloxy group may be used alone or in any desired
combination of several urethane oligomers having (meth)acryloxy
group; the specific types and combination thereof depend from the
desired properties of the products.
[0054] "Polyisoprene having (meth)acryloxy group or vinyl group":
Another non-limited example of photo curable oligomer or polymer
having (meth)acryloxy group or vinyl group is polyisoprene having
(meth)acryloxy group or vinyl group.
[0055] Generally, this is an isoprene polymer modified by reactive
functional groups, for example, polyisoprene grafted with acrylate
group, or polyisoprene grafted with vinyl groups. Wherein the
backbone or main chain of the macromolecule polyisoprene may have a
number average molecular weight of 10000-50000 Daltons, preferably
12000-40000 Daltons; more preferably 15000-35000 Daltons. As to the
grafted reactive groups, this exemplified acrylate functional group
or vinyl functional group may be located at the end(s) of the
isoprene oligomer, or may be pendant to branches of isoprene
oligomer.
[0056] The polyisoprene having acryloxy or vinyl functional group
used in accordance with the present invention may have a Brookfield
viscosity, at a temperature of 25.degree. C. at a shear rate of
2.55 s.sup.-1, several thousands to tens of thousands cps, for
example 10000-100000 cps, or 15000-80000 cps, or 25000-60000 cps,
measurable by HAAKE Rotational Rheometer with a cone plate (35 mm
diameter).
[0057] Specifically, the non-limited examples of polyisoprene
having acryloxy or vinyl functional group are as follows:
polyisoprene UC203, UC102, commercially available from KURARAY CO.,
LTD, and the like.
[0058] In the adhesive composition in accordance with the present
invention, polyisoprene having acryloxy or vinyl functional group
can be used in at an amount of 10-80 wt %, preferably 20-70 wt %,
more preferably 30-60 wt %.
[0059] According to the present invention, in the adhesive
composition, polyisoprene having acryloxy or vinyl group may be
used alone or in any combination of several polyisoprenes having
acryloxy or vinyl group. The specific types and combination thereof
depend from the desired properties of the adhesive products.
[0060] "(Meth)acrylate": The adhesive composition in accordance
with the present invention also makes use of (meth)acrylate. Said
(meth)acrylate is, for example, aliphatic alkyl(meth)acrylate, and
(meth)acrylate having epoxy function, and the like. It could be a
monofunctional (meth)acrylate, i.e., there is only one
(meth)acrylate group within its molecule, it could also be a
multifunctional (meth)acrylate, i.e., it is a (meth)acrylate having
two or more than two (meth)acrylate group within its molecule.
[0061] The (meth)acrylate monomer preferably is monofunctional- and
multifunctional alkyl(meth)acrylates, monofunctional- and
multifunctional alkenyl(meth)acrylates, and monofunctional- and
multifunctional heterocyclo(meth)acrylates. Said alkyl moiety
preferably is an alkyl group having from 1 to 20 carbon atoms,
which may further have one or more substituents selected from an
alkyl group having from 1 to 20 carbon atoms, an alkoxy group
having from 1 to 20 carbon atoms, an aryloxy group having from 6 to
20 carbon atoms, an epoxy group having from 2 to 20 carbon atoms,
hydroxyl and the like. The alkenyl moiety preferably is an alkenyl
group having from 2 to 20 carbon atoms, which may further have one
or more substituents selected from an alkyl group having from 1 to
20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms,
an acryloxy group having from 6 to 20 carbon atoms, an epoxy group
having from 2 to 20 carbon atoms, hydroxyl and the like. The
heterocyclic group preferably is a heterocyclic group having from 2
to 20 carbon atoms, and having a hetero atom selected from nitrogen
and oxygen. The heterocyclic group may have one or more
substituents selected from an alkyl group having from 1 to 20
carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an
aryloxy group having from 6 to 20 carbon atoms, an epoxy group
having from 2 to 20 carbon atoms, hydroxyl and the like.
[0062] Preferred examples of monofunctional acrylate component are
isobornyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate,
alkoxylated tetrahydrofurfuryl(meth)acrylate, and mixtures
thereof.
[0063] Preferred examples of multifunctional acrylate component
are: ethylene glycol di(meth)acrylate, 1,6-hexanediol
di(meth)acrylate, 1,4-butanediol di(meth)acrylate, pentaerythritol
tri(meth)acrylate. pentaerythritol tetra(meth)acrylate,
trimethylolpropane(meth)acrylate, tetraethylene glycol
di(meth)acrylate and the like, and mixture thereof.
[0064] Preferably said (meth)acrylate is selected from the group
consisting of: methyl(meth)acrylate, ethyl(meth)acrylate,
butyl(meth)acrylate, 2-(2-ethoxyethoxyl)ethyl acrylate,
tetrahydrofurfuryl(meth)acrylate, lauryl acrylate, isooctyl
acrylate, isodecyl acrylate, 2-phenoxy ethyl acrylate,
2-ethylhexyl(meth)acrylate, isobornyl(meth)acrylate,
dicyclopentenyloxyethyl(meth)acrylate,
dicyclopentadienyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate,
2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate,
caprolactone acrylate, morpholine(meth)acrylate, hexanediol
di(meth)acrylate, ethylene glycol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, pentaerythritol
tetrahydrofuran(meth)acrylate, hydroxylpropyl(meth)acrylate,
ethylene glycol dicyclopentenyl ether(meth)acrylate, and any
combination thereof.
[0065] Most preferably used (meth)acrylate monomers are selected
from the group consisting of: isobornyl acrylate, hydroxypropyl
acrylate, 2-(2-ethoxyethoxy) ethyl acrylate. ethylene glycol
dicyclopentenyl ether methacrylate, and combination thereof.
[0066] Usually, the amount of (meth)acrylate component would depend
from the amounts of other components used for forming the adhesive
composition, and the desired properties of the adhesive
composition. In the embodiments of adhesive composition of the
present invention, based on the total weight of adhesive weight,
the contents of (meth)acrylate in the adhesive composition is 5-55
wt %; preferably 10-55 wt %, more preferably 10-50 wt %, more
preferably 20-45 wt %; more preferably 25-40 wt %, and most
preferably 20-40 wt %.
[0067] "Photoinitiator": According to the present invention, the
adhesive composition comprises photoinitiator. Said photoinitiator
may include UV-photoinitiator and visible light photoinitiator.
[0068] In the context of the present invention, said photoinitiator
preferably refers to UV-photoinitiator. UV-photoinitiator is well
known in the art, and can be used to initiate the photo
polymerization of all the above functionalized photo curable
oligomer, polymer having (meth)acryloxy group or vinyl group.
[0069] A variety of UV photoinitiators may be employed. UV
photoinitiators are generally effective in the wavelength range of
200 to 400 nm, and particularly in the portion of the spectrum that
borders on the invisible light and the visible portion just beyond
this spectrum, e.g. from >200 nm up to about 390 nm. Examples
thereof may be benzyl ketal, hydroxy ketone, amino ketone, acyl
phosphine oxide, and the like.
[0070] Photoinitiators that will respond to UV radiation to
initiate and induce cure of the (meth)acrylate functionalized
curable component, which are useful in the present invention
include preferably benzophenone and substituted benzophenones,
acetophenone and substituted acetophenones, benzoin and its alkyl
esters, diethoxy acetophenone, benzoin methyl ether, benzoin ethyl
ether, benzoin isopropyl ether, N-methyldiethanolamine
benzophenone, 2-hydroxy-methyl-1-phenylpropan-1-one,
2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone,
diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and combination
thereof.
[0071] According to the present invention, the UV-photoinitiator
may be used alone, or in any desired combination thereof. Above
UV-photoinitiators are just for purpose of illustration, rather
than limiting the UV-photoinitiator useful in the present
invention.
[0072] The amount of UV-photoinitiator used, based on the total
weight of the adhesive composition, may be 0.5-5 wt %, preferably
1-4 wt %, more preferably 2-3 wt %.
[0073] "Thermal Initiator": In the adhesive composition according
to present invention, thermal initiator is to be used to initiate
the polymerization and cure of the composition. Thermal initiator
usually includes azo compounds, peroxides, and other thermal
initiator(s) well known to those skilled in the art, which is
capable of releasing radicals under heating conditions, and
combination thereof. Preferably peroxides are used in the present
invention. The peroxide useful in the present invention preferably
includes organic peroxide and inorganic peroxide. Non-limited
examples of organic peroxide may be peroxy-dicarbonate, for example
di(2-ethylhexyl)peroxydicarbonate; acyl peroxide, for example,
dilauroyl peroxide; alkyl peroxide, for example
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; peroxyesters, for
example tert-butyl peroxybenzoate, and the like.
[0074] Inorganic peroxide is also well known in the art, and
non-limited examples of organic peroxide may be persulfate, for
example, potassium persulfate, sodium persulfate and ammonium
persulfate, and the like.
[0075] In the adhesive composition of the present invention,
peroxide thermal initiator may be used alone, or two or even more
peroxides may be used together.
[0076] In the adhesive composition of the present invention the
thermal initiator preferably used is organic peroxide, particularly
peroxy esters, and the preferred example thereof is tert-butyl
peroxybenzoate, as well as alkyl peroxide, the non-limited example
thereof is 1,1-di(tert-butyl peroxy)-3,3,5-trimethyl
cyclohexane.
[0077] The amount of the ester peroxide and alkyl peroxide used,
based on the total weight of the adhesive composition, is 0.5-5 wt
%, preferably 1-4 wt %, more preferably 2-3 wt %.
[0078] "Liquid Polybutadiene": In accordance with the present
invention, the adhesive composition may optionally include liquid
polybutadiene component. Preferably, the liquid polybutadiene here
is an oligomer of butadiene, i.e., it is a product obtainable by
anion polymerization or coordination polymerization, and the degree
of polymerization, or the molecular weight thereof or viscosity
thereof may be controllable by adjusting the initiator, the amount
thereof, the chain transfer agent, the amount thereof, and etc.
[0079] The liquid polybutadiene may have a number average molecular
weight of 1000-30000 Daltons, preferably 1500-25000 Daltons, more
preferably 2000-20000 Daltons, more preferably 3000-10000 Daltons;
and the Brookfield viscosity thereof at 25.degree. C. at a shear
rate of 2.55 s.sup.-1 may be hundred cps to tens of thousands cps,
for example 500 cps-50000 cps, preferably 1000 cps-30000 cps, more
preferably 3000 cps-20000 cps, still more preferably 5000 cps-15000
cps, measurable by HAAKE Rotational Rheometer with a cone plate (35
mm diameter).
[0080] The liquid polybutadiene useful in the present invention may
be those commercially available products, and the non-limiting
examples thereof may be: Polybutadiene Ricon 130, Ricon156, LBR307,
LBR305 and etc commercially available from Sartomer Company, Inc.;
wherein Polybutadiene Ricon 130 has a number average molecular
weight of about 2500; and Polybutadiene Rican 156 has a number
average molecular weight of 1400; or Polybutadiene LBR307, LBR305
commercially available from KURARAY CO., LTD; the number average
molecular weight thereof are about 8000 and 26000,
respectively.
[0081] Most preferably, the liquid polybutadiene is selected from
the group consisting of: PB-3600 from Daicel Chemical co., and
Ricon130 polybutadiene from Sartomer Company, Inc.
[0082] In the adhesive composition of the present invention, based
on the total weight of the adhesive composition, the amount of
liquid polybutadiene used may be 0-50 wt %, preferably 10-40 wt %,
more preferably 20-35 wt %.
[0083] "Other Components": In addition to above components, the
adhesive composition according to the present invention may
optionally contain other additives well known to those skilled in
the art, for example, non limiting to: light stabilizer, thermal
stabilizer, promoter to photo initiation, promoter to thermal
initiation, level agent, toughening agent, thickening agent, and
etc.
[0084] Based on the total weight of said adhesive composition, said
additives may account for 0.01-1 wt %, or 1%-2 wt %, or 0-2 wt
%.
[0085] "Substrate to be bonded": The present inventive adhesive
composition is particularly suitable for bonding touch screen and
substrate of electronic devices. Non-limited examples of the
electronic devices include mobile phone, television, palm PDA,
notebook, table PC, and other devices having a touch screen. The
touch screen may be any type of panel in the art, for example,
liquid crystal display panel, plasma display panel, and organic
electroluminescent panel, and the like.
[0086] The substrate may be any type in the art as well, generally
it includes glass or polymeric material. Useful glass comprises,
but not limiting to, borosilicate glass, soda-lime glass, and any
other glasses suitable for display screen. Useful polymeric
material includes polyester film, for example polyethylene
terephthalate PET, polycarbonate film or polyacrylate film, for
example, polymethyl methacrylate film, and cycloolefin polymeric
film, for example, ZEONOX and ZEONOR from Zeon Chemicals L. P. Said
substrate preferably has a reflective index comparable with those
of display screen, for example, from about 1.4 to about 1.7.
Typical thickness of substrate may be about 0.5 to about 5 mm.
[0087] "Production of Adhesive": The adhesive composition in
accordance with the present invention may be prepared as follows:
into a mixing container with conventional stirring means, under the
condition of substantially complete darkness, in a predetermined
ratio, each components of the adhesive composition are fed into and
mixed. Mixing is usually conducted at ambient temperature, or a
temperature slightly higher or lower than ambient temperature.
Mixing should last for a sufficient time to ensure a uniformly
dispersed components, thus obtaining the adhesive composition.
Store the thus obtained adhesive composition in dark environment,
for subsequent bonding between touch screen and substrate.
[0088] The volume of the mixing container is not specifically
defined, per specific requirements, it could be, for example, about
1-100 L, or 5-50 L, or 10-30 L, and etc. The mixing container could
be such as those commercially available; with a conventional
stirring means, such as, paddle stirrer, anchor stirrer, propeller
stirrer and the like, the speed of rotation generally depends from
the type of the stirrer and the viscosity of adhesive components,
and etc. For example. It could be 10 rpm-500 rpm, or 50 rpm-300
rpm, or rotor-stator stirrer may also be adopted, with a speed of
rotation of, for example, 300-4000 rpm, preferably 1500-3000 rpm.
For example, the mixing time could be about 1-10 minutes, or 2 to 8
minutes, or 4-6 minutes and etc; thus obtaining the adhesive
composition.
[0089] "UV Cure": After the touch screen and substrate is bonded
with the adhesive composition in accordance with the present
invention, the bonded assembly should be cured. As to the UV cure
of the bonded assembly, UV source covering the range of 200 nm-400
nm wavelength could be adopted, for example, with an irradiation
power of 100 mW/cm.sup.2. Per specific requirements, irradiation
could be conducted for seconds to tens of seconds, for example 5-30
seconds, or even longer. The irradiation power and time could be
easily determined by those skilled in the art per the requirements
of products.
[0090] The present invention may take use of commercially available
lamp assembly, including an arc lamp, for example, please refer to
those disclosed in U.S. Pat. No. 6,520,663 and 6881964, the
contents thereof are incorporated here by reference. UV cure oven
may also be adopted, for example, Loctite UVALOC 1000 from Henkel
AG.
[0091] "Thermal Cure": After UV cure, the bonded sample will be
further thermal cured. Thermal cure may be conducted by any
conventional means in the art without any limitation. For example,
it may be performed by using an oven with a hot air circulating
oven with adjustable temperature controller. The specific thermal
cure temperature may be, for example 50-150.degree. C., or
60-140.degree. C., 70-120.degree. C., most preferably 80-90.degree.
C. The time of thermal cure depends on the specific adhesive
composition, for example, in case of high content of thermal
initiator, cure time could be relatively short, such as 30 minutes
to 1.5 hours, and in case of low content of thermal initiator, cure
time could be relatively long, such as 1-3 hours.
[0092] "Testing Methods involved in the present invention": In
accordance with the present invention, specifically, testing
methods involved are described as follows:
[0093] 1. Viscosity: Viscosity is used to describe the flowing
resistance of a liquid, and in principle, it reflects the inner
molecular friction. In the present invention, the testing
instrument used to measure the viscosity of uncured adhesive
composition may be commercially available Brookfield rotating
viscosity meters, and testing temperature is ambient temperature
(about 25.degree. C.), or room temperature, or 60.degree. C. and
etc., and the testing may preferably be performed per the
specification in ASTM D1086-1997. The unit of viscosity is poise or
centipoise. Preferably, viscosity is measured at 25.degree. C. at a
shear rate of 2.55 s.sup.-1 by HAAKE Rotational Rheometer with a
cone plate (35 mm diameter).
[0094] 2. Light Transmittance: Light transmittance is an index to
describe the transmission of light through a material, typically,
it is expressed as a ratio of intensity of transmissive light
I.sub.t to intensity of incident light I.sub.0. After complete
cure, the testing of light transmittance of the adhesive
composition may typically measured by conventional commercially
available UV light spectrophotometer. The thickness of the two
pieces of testing samples adopted in the adhesive composition may
be controlled in a certain range, for example, about 100 .mu.m.
[0095] Testing of light transmittance may preferably be conducted
according to the specification in ASTM D1005-2007.
[0096] Preferably an adhesive is regarded as optically transparent,
if it exhibits an optical transmission of at least 85%.
[0097] 3. Bonding Strength: Bonding strength is used to
characterize the joining strength between two pieces of bonded
materials, after the bonding between the samples are sufficiently
cured.
[0098] The thickness of the adhesive coating generally is
controlled per specific requirements, such as at about 100 .mu.m.
Substrate may be selected, per requirements, as glass sheet,
acrylate resin sheet, or polyester sheet. In the present testing,
the size of glass substrate sample is typically of 100 mm long, 10
mm wide and 2 mm thick.
[0099] Testing equipment for bonding strength may preferably be an
universal tensile machine, the mode thereof may be, for example,
Instron 5569 from Instron Inc.
[0100] For example, the procedure for measuring the bonding
strength is, for example, as follows: dropping the adhesive to be
tested in one of the center of a piece of glass sheet, copper wire
having 100 um in diameter is disposed at two sides of the adhesive
for the purpose of controlling the thickness thereof. Then another
piece of glass is lapped vertically above the adhesive, forming a
lapping sample in cross form. The lapped sample is further put into
a UV cure oven (for example, Loctite UVALOC 1000, Henkel AG) to
carry out UV cure. Predetermined condition is: irradiation for 30
seconds, the power thereof is 100 mW/cm.sup.2.
[0101] The cured sample is further placed at room temperature for
24 hours, then universal tensile machine is used to tensile the
bonded sample vertically in opposed direction. The tensile speed
may be set as 2 inches/min. The bonding strength (unit: MPa) could
be obtainable via dividing the value of force recorded in the
machine by the lapping area.
[0102] 4. Molecular Weight: Molecular weight of the starting
materials of the adhesive composition includes number average
molecular weight, weight average molecular weight, and the like.
Unless indicated otherwise, measurement of said molecular weight is
conducted by using gel permeation chromatography (GPC) well known
and widely adopted in the relevant art. In the measurement,
polystyrene having a narrow molecular weight distribution may be
used as standard, for example, and tetrahydrofuran may be used as
the mobile phase, and the flowing speed, for example, may be 0.8
mL/min, and the column temperature for example, may be 35.degree.
C.
EXAMPLES
[0103] Hereafter examples are provided to further describe the
present invention, said examples are only for illustration to the
present invention; rather, it should not be construed as a
limitation to the present invention.
Specific Testing Conducted in Examples
Test 1: UV Cure Experiment
[0104] At room temperature, a UV light source covering the emitting
wavelength of 200 nm-400 nm, having an irradiation power of 100
mW/cm.sup.2 was used to irradiate the boding of adhesive
composition between glass and polycarbonate (PC) sheets for 30
seconds.
Test 2: Thermal Cure Experiment
[0105] Under the condition of darkness, in an oven with an
adjustable temperature controller, the highest temperature thereof
was no less than 200.degree. C., the adhesive composition between
glass and PC sheets was thermal cured. The cure time depended on
specific components of the adhesive composition.
Test 3: Bonding Strength Experiment
[0106] In the present invention, under the condition of 100
mW/cm.sup.2 UVA irradiation, the adhesive composition between glass
sheet and glass sheet was cured for 30 seconds, and according to
the above mentioned testing method, the bonding strength of the
adhesive composition was measured.
Test 4: Light Transmittance Experiment
[0107] An UV light-visible light spectrophotometer was adopted to
measure the light transmittance of the adhesive material after
curing. The thickness of the cured adhesive material was controlled
at about 100 .mu.m. Testing method was per the specification of
ASTM D1005-2007. After the irradiation of 100 mW/cm.sup.2 UVA for
the adhesive composition between glass and glass sheets for 30
seconds, the light transmittance of the adhesive composition was
measured accordingly.
Test 5: Shadow Area Checking
[0108] Kept the area applied by adhesive composition or the lapped
area between the testing sheets in complete darkness. After such an
arrangement, thermal cure of the adhesive composition was
conducted. After the thermal cure testing condition was met,
checked the results of the body to be bonded.
TABLE-US-00001 Raw materials used Components Products urethane
oligomer having Genomer 4188/EHA (Rahn AG): mixture consisting of
80 (meth)acryloxy group 1-1 wt. % of a monoacrylate-functional
polyesterbased oligomer comprising at least one urethane bond, and
20% 2-ethylhexyl acrylate monomers; the oligomer comprised by
GENOMER 4188 has a weight average molecular weight Mw of about
8,000, average degree of functionality about 1, viscosity at
25.degree. C.: about 70000 cps, Tg: about -3.degree. C. urethane
oligomer having CN 9021 (Sartomer Company, Inc.), average degree of
(meth)acryloxy group 1-2 functionality: 2, viscosity at 25.degree.
C.: about 32000 cps, Tg: -54.degree. C. urethane oligomer having CN
8004 (Sartomer Company, Inc.); average degree of (meth)acryloxy
group 1-3 functionality: less than 2, viscosity at 60.degree. C.:
about 9000 cps, Tg: about -3.degree. C. polyisoprene having UC-102
(Kuraray Company), average degree of methacryloxy group 2-1
functionality: 2, number average molecular weight: about 17,000,
Tg: -60.degree. C. polyisoprene having UC-203 (Kuraray Company),
average degree of methacryloxy group 2-2 functionality: 3, number
average molecular weight: about 35,000, Tg: -60.degree. C. liquid
polybutadiene 3-1 Ricon130 (Sartomer Company, Inc.), number average
molecular weight: about 2500 (meth)acrylate monomer 4-1
commercially available isobornyl acrylate (meth)acrylate monomer
4-2 commercially available hydroxypropyl methacrylate
(meth)acrylate monomer 4-3 commercially available
2-(2-ethoxyethoxy)ethyl acrylate (meth)acrylate monomer 4-4
commercially available ethylene glycol dicyclopentenyl ether
methacrylate UV-photoinitiator 5-1
2-hydroxy-2-methyl-1-phenyl-1-propanone (BASF company, Inc.)
UV-photoinitiator 5-2 diphenyl(2,4,6-trimethylbenzoyl)-phosphine
oxide (BASF company, Inc.) thermal initiator 6-1
1,1-bis(tert-butylperoxy)-3,3,5-trimethyl cyclohexane (J&K
Scientific Ltd.) thermal initiator 6-2 tert-butyl
peroxybenzoate
[0109] Other compounds used in the examples are all chemical pure
reagents, and are all commercially available.
Example 1
Inventive
[0110] Adhesive composition 1 was formulated according to the
composition in Table 1 and formulating method as stated below:
TABLE-US-00002 TABLE 1 Components Contents urethane oligomer having
(meth) 70 parts by weight acryloxy group 1-1 (meth)acrylate 4-1 10
parts by weight (meth)acrylate 4-2 7 parts by weight (meth)acrylate
4-3 7 parts by weight UV-photoinitiator 5-1 2 parts by weight
UV-photoinitiator 5-2 1 parts by weight thermal initiator 6-1 2
parts by weight thermal initiator 6-2 1 parts by weight
[0111] The formulating procedure of the adhesive composition was as
follows: Under a condition of darkness, feeding all above
components (total: 100 g) into a plastic barrel having a volume of
150 g in the order listed above, mounting a SpeedMixer.TM. mixer
produced by FlackTech Inc. in the barrel, and all the components
were mixed and dispersed at a rotation of 2000-2400 rpm for 10
minutes, thus obtaining a transparent adhesive composition 1.
Example 2
Inventive
[0112] Adhesive composition 2 was formulated according to the
composition in Table 2 and method as stated in example 1.
TABLE-US-00003 TABLE 2 Components Contents urethane oligomer having
(meth) 70 parts by weight acryloxy group 1-1 (meth)acrylate 4-1 11
parts by weight (meth)acrylate 4-2 7 parts by weight (meth)acrylate
4-3 7 parts by weight UV-photoinitiator 5-1 2 parts by weight
UV-photoinitiator 5-2 1 parts by weight thermal initiator 6-1 2
parts by weight
Example 3
Not Inventive
[0113] Adhesive composition 3 was formulated according to the
composition in Table 3 and method as stated in example 1.
TABLE-US-00004 TABLE 3 Components Contents urethane oligomer having
(meth) 70 parts by weight acryloxy group 1-1 (meth)acrylate 4-1 11
parts by weight (meth)acrylate 4-2 8 parts by weight (meth)acrylate
4-3 8 parts by weight UV-photoinitiator 5-1 1 parts by weight
Example 4
Inventive
[0114] Adhesive composition 4 was formulated according to the
composition in Table 4 and method as stated in example 1.
TABLE-US-00005 TABLE 4 Components Contents urethane oligomer having
(meth) 65 parts by weight acryloxy group 1-2 urethane oligomer
having (meth) 20 parts by weight acryloxy group 1-3 (meth)acrylate
4-1 10 parts by weight (meth)acrylate 4-2 7 parts by weight
(meth)acrylate 4-3 7 parts by weight UV-photoinitiator 5-1 2 parts
by weight thermal initiator 6-1 2 parts by weight thermal initiator
6-2 1 parts by weight
Example 5
Inventive
[0115] Adhesive composition 5 was formulated according to the
composition in Table 5 and method as stated in example 1.
TABLE-US-00006 TABLE 5 Components Contents urethane oligomer having
(meth) 65 parts by weight acryloxy group 1-2 urethane oligomer
having (meth) 20 parts by weight acryloxy group 1-3 (meth)acrylate
4-1 10 parts by weight (meth)acrylate 4-2 7 parts by weight
(meth)acrylate 4-3 7 parts by weight UV-photoinitiator 5-1 2 parts
by weight UV-photoinitiator 5-2 1 parts by weight thermal initiator
6-1 2 parts by weight
Example 6
Inventive
[0116] Adhesive composition 6 was formulated according to the
composition in Table 6 and method as stated in example 1.
TABLE-US-00007 TABLE 6 Components Contents polyisoprene having 30
parts by weight methacryloxy group 2-1 liquid polybutadiene 3-1 40
parts by weight (meth)acrylate 4-1 12 parts by weight
(meth)acrylate 4-2 12 parts by weight UV-photoinitiator 5-1 2 parts
by weight UV-photoinitiator 5-2 1 parts by weight thermal initiator
6-1 2 parts by weight thermal initiator 6-2 1 parts by weight
Example 7
Inventive
[0117] Adhesive composition 7 was formulated according to the
composition in Table 7 and method as stated in example 1.
TABLE-US-00008 TABLE 7 Components Contents Polyisoprene having 30
parts by weight methacryloxy group 2-1 liquid polybutadiene 3-1 40
parts by weight (meth)acrylate 4-2 12 parts by weight
(meth)acrylate 4-4 12 parts by weight UV-photoinitiator 5-1 2 parts
by weight UV-photoinitiator 5-2 1 parts by weight thermal initiator
6-1 2 parts by weight thermal initiator 6-2 1 parts by weight
Example 8
Not Inventive
[0118] Adhesive composition 8 was formulated according to the
composition in Table 8 and method as stated in example 1
TABLE-US-00009 TABLE 8 Components Contents Polyisoprene having
methacryloxy 30 parts by weight group 2-1 polyisoprene having
methacryloxy 10 parts by weight group 2-2 liquid polybutadiene 3-1
33 parts by weight (meth)acrylate 4-1 12 parts by weight
(meth)acrylate 4-2 12 parts by weight UV-photoinitiator 5-1 2 parts
by weight UV-photoinitiator 5-2 1 parts by weight
Example 9
Inventive
[0119] Adhesive composition 9 was formulated according to the
composition in Table 9 and method as stated in example 1.
TABLE-US-00010 TABLE 9 Components Contents polyisoprene having 50
parts by weight methacryloxy group 2-1 (meth)acrylate 4-1 12 parts
by weight (meth)acrylate 4-2 12 parts by weight (meth)acrylate 4-4
20 parts by weight UV-photoinitiator 5-1 2 parts by weight
UV-photoinitiator 5-2 1 parts by weight thermal initiator 6-1 2
parts by weight thermal initiator 6-2 1 parts by weight
Example 10
Inventive
[0120] Adhesive composition 10 was formulated according to the
composition in Table 10 and method as stated in example 1.
TABLE-US-00011 TABLE 10 Components Contents polyisoprene having 45
parts by weight methacryloxy group 2-1 polyisoprene having 15 parts
by weight methacryloxy group 2-2 (meth)acrylate 4-1 17 parts by
weight (meth)acrylate 4-4 17 parts by weight UV-photoinitiator 5-1
2 parts by weight UV-photoinitiator 5-2 1 parts by weight Thermal
initiator 6-1 2 parts by weight Thermal initiator 6-2 1 parts by
weight
[0121] The adhesive compositions 1-10 of Examples 1-10 were tested
as mentioned in test 1 to test 5, and the results were showed in
Table 11 below:
TABLE-US-00012 TABLE 11 Example 1 Example 2 Example 3 Example 4
Example 5 test 1 cured within cured within cured within cured
within cured within 30 seconds 30 seconds 30 seconds 30 seconds 30
seconds test 2 cured within 1 cured within 2 Could not cured within
1 cured within 2 hour at 80.degree. C. hours at 90.degree. C. cured
hour at 80.degree. C. hours at 90.degree. C. test 3 >0.6 MPa
>0.6 MPa >0.6. MPa >0.4 MPa >0.4 MPa test 4 >92%
>92% >92% 92% 92% test 5 composition composition composition
composition composition cured cured in liquid cured cured Example 6
Example 7 Example 8 Example 9 Example 10 test 1 cured within cured
within cured within cured within cured within 30 seconds 30 seconds
30 seconds 30 seconds 30 seconds test 2 cured within 1 cured within
2 Could not cured within 1 cured within 2 hour at 80.degree. C.
hours at 90.degree. C. cured hour at 80.degree. C. hours at
90.degree. C. test 3 >0.6 MPa >0.6 MPa >0.6.MPa >0.4
MPa >0.4 MPa test 4 >92% >92% >92% 92% 92% test 5
composition composition composition composition composition cured
cured in liquid cured cured
* * * * *