U.S. patent application number 09/772982 was filed with the patent office on 2001-09-13 for pressure-sensitive adhesive composition and pressure-sensitive adhesive sheets thereof, and sealing material, reinforcing sheet, and printable pressure-sensitive adhesive sheet using the same.
Invention is credited to Ando, Masahiko, Hikosaka, Waka, Kojima, Makoto, Kouno, Shin-Ichi, Kume, Katsuya, Kuramoto, Mitsuo, Mashiko, Hiroaki, Matsuoka, Naoki, Soeda, Yoshikazu, Tokunaga, Yasuyuki, Wada, Hiroshi, Yamamoto, Hiroshi, Yamanaka, Takeshi.
Application Number | 20010021451 09/772982 |
Document ID | / |
Family ID | 27581781 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010021451 |
Kind Code |
A1 |
Tokunaga, Yasuyuki ; et
al. |
September 13, 2001 |
Pressure-sensitive adhesive composition and pressure-sensitive
adhesive sheets thereof, and sealing material, reinforcing sheet,
and printable pressure-sensitive adhesive sheet using the same
Abstract
A pressure-sensitive adhesive composition, wherein the storage
elastic modulus [G'] at room temperature is at least
2.times.10.sup.6 dyne/cm.sup.2 and the adhesive strength at room
temperature is 1 kg/20 mm width or higher. Preferably, a
pressure-sensitive adhesive composition comprising a polymer having
a polycarbonate structure having a repeating unit represented by
the following formula 1 wherein R represents a straight chain or
branched hydrocarbon group having from 2 to 20 carbon atoms, a
pressure-sensitive adhesive sheet, a sealing material, a
reinforcing sheet, and a pressure-sensitive sheet for printing,
each having the pressure-sensitive adhesive composition.
Inventors: |
Tokunaga, Yasuyuki; (Osaka,
JP) ; Ando, Masahiko; (Osaka, JP) ; Yamanaka,
Takeshi; (Osaka, JP) ; Hikosaka, Waka; (Osaka,
JP) ; Kojima, Makoto; (Osaka, JP) ; Kouno,
Shin-Ichi; (Osaka, JP) ; Mashiko, Hiroaki;
(Osaka, JP) ; Wada, Hiroshi; (Osaka, JP) ;
Yamamoto, Hiroshi; (Osaka, JP) ; Soeda,
Yoshikazu; (Osaka, JP) ; Matsuoka, Naoki;
(Osaka, JP) ; Kume, Katsuya; (Osaka, JP) ;
Kuramoto, Mitsuo; (Osaka, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037-3213
US
|
Family ID: |
27581781 |
Appl. No.: |
09/772982 |
Filed: |
January 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09772982 |
Jan 31, 2001 |
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08913449 |
Sep 15, 1997 |
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6218006 |
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08913449 |
Sep 15, 1997 |
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PCT/JP96/00695 |
Mar 15, 1996 |
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Current U.S.
Class: |
428/343 ;
428/304.4 |
Current CPC
Class: |
Y10T 428/1462 20150115;
Y10T 428/2891 20150115; Y10T 428/28 20150115; Y10T 428/249953
20150401; Y10T 428/2861 20150115; Y10T 428/2852 20150115; C09J
169/00 20130101 |
Class at
Publication: |
428/343 ;
428/304.4 |
International
Class: |
B32B 003/26; B32B
007/12; B32B 015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 1995 |
JP |
HEI. 7-084846 |
Jul 28, 1995 |
JP |
HEI. 7-212425 |
Aug 17, 1995 |
JP |
HEI. 7-233321 |
Sep 15, 1995 |
JP |
HEI. 7-262275 |
Sep 15, 1995 |
JP |
HEI. 7-262276 |
Dec 8, 1995 |
JP |
HEI. 7-319884 |
Jan 22, 1996 |
JP |
HEI. 8-007943 |
Jan 22, 1996 |
JP |
HEI. 8-007944 |
Feb 21, 1996 |
JP |
HEI. 8-033792 |
Feb 29, 1996 |
JP |
HEI. 8-042310 |
Mar 1, 1996 |
JP |
HEI. 8-044406 |
Claims
1. A pressure-sensitive adhesive composition, wherein the storage
elastic modulus [G'] at room temperature is at least
2.times.10.sup.6 dyne/cm.sup.2 and the adhesive strength at room
temperature is at least 1 kg/20 mm width.
2. A pressure-sensitive adhesive composition of claim 1, wherein
the storage elastic modulus [G'] at -30.degree. C. is
3.times.10.sup.7 dyne/cm.sup.2 or lower.
3. A pressure-sensitive adhesive composition of claim 1, wherein
the storage elastic modulus [G'] at 80.degree. C. is
1.times.10.sup.6 dyne/cm.sup.2 or higher.
4. A pressure-sensitive adhesive composition comprising a polymer
having a polycarbonate structure having a repeating unit
represented by a following formula, 7wherein R represents a
straight chain or branched hydrocarbon group having from 2 to 20
carbon atoms.
5. A pressure-sensitive adhesive composition of claim 4, wherein
said composition comprises a polyester having a weight average
molecular weight of at least 10,000 and synthesized from diol
components indispensably containing polycarbonate diol and
dicarboxlic acid components indispensably containing a dicarboxylic
acid having an aliphatic hydrocarbon group of from 2 to 20 carbon
atoms or an alicyclic hydrocarbon group as the molecular
structure.
6. A pressure-sensitive adhesive composition of claim 4, wherein
the solvent-insoluble component of the polymer is from 1 to 30% by
weight and the self-adhesive strength is at least 2.0 kg/20 mm
width.
7. A pressure-sensitive adhesive composition of claim 4, wherein
the self-adhesive strength is at least 100 g/20 mm width and the
adhesive strength is not higher than 2,000 g/20 mm width.
8. A pressure-sensitive adhesive composition of claim 7, wherein
the polymer having a polycarbonate structure is crosslinked and the
solvent-insoluble component is from 60 to 95% by weight.
9. A pressure-sensitive adhesive composition of claim 4, wherein
said composition contains an acrylic polymer having a glass
transition temperature of -10.degree. C. or lower, together with
the polymer having a polycarbonate structure, at a rate of from 10
to 90% by weight of the sum total of the acrylic polymer and the
polymer having the polycarbonate structure.
10. A pressure-sensitive adhesive composition of claim 4, wherein
said composition contains a resin having a softening point of at
least 80.degree. C., together with the polymer having a
polycarbonate structure, at a rate of from 10 to 50% by weight of
the sum total of the resin and the polymer having the polycarbonate
structure.
11. A pressure-sensitive adhesive sheet having a layer comprising
the pressure-sensitive adhesive composition described in claim 1 or
4.
12. A pressure-sensitive adhesive sheet of claim 11, wherein said
sheet has the layer comprising the pressure-sensitive adhesive
composition on one surface or both surfaces of a base material.
13. A sealing material having a layer comprising the
pressure-sensitive adhesive composition described in claim 1 or 4
on a sealing base material.
14. A sealing material of claim 13, wherein the sealing base
material is a sheet-form material or a foam material of a synthetic
resin or a synthetic rubber or is made up of a laminate formed by
laminating a synthetic resin film on the sheet-form material or the
foam material.
15. A sealing material of claim 13, wherein the sealing base
material is a metal foil or a fluorine resin film, or is made up of
a material having a moisture proofing effect, such as a composite
material formed by forming a metal layer or a fluorine resin layer
on a synthetic resin film.
16. A reinforcing sheet for reinforcing a terminal portion of a
tape electric wire having such a structure that plural electrically
conductive wires are arranged in an insulating layer at an
interval, comprising an insulating base material having formed on
one surface thereof a layer comprising the pressure-sensitive
adhesive composition descried in claim 1 or 4.
17. A pressure-sensitive adhesive sheet, a sealing sheet, or a
reinforcing sheet of claim 12, 13 or 16 respectively, wherein a
release liner not subjected to a silicone (back-surface) release
coating is stuck to the pressure-sensitive adhesive surface.
18. A pressure-sensitive adhesive sheet, a sealing sheet, or a
reinforcing sheet of claim 17, wherein the release liner not
subjected to a silicone release coating is a polyolefin film series
film made up of polyethylene, polypropylene, an ethylene-propylene
copolymer, or a mixture thereof or a film the surface of which is
processed with the foregoing polyolef in, and the releasing
strength of the release liner is 200 g/50 mm width or lower.
19. A pressure-sensitive adhesive sheet, a sealing sheet, or a
reinforcing sheet of claim 12, 13 or 16 respectively, wherein the
sheet has a layer comprising the pressure-sensitive adhesive
composition on one surface of a base material, the back side of the
base material is not subjected to a silicone release coating, and
the sheet is wound in a roll form without inserting a release
liner.
20. A pressure-sensitive adhesive sheet, a sealing sheet, or a
reinforcing sheet of claim 19, wherein the sheet has a layer
comprising the pressure-resisting adhesive composition on one
surface of the base material, at least the back side of the base
material is constituted with a polyolefin made up of polyethylene,
polypropylene, an ethylene-propylene
Description
TECHNICAL FIELD
[0001] The present invention relates to a pressure-sensitive
adhesive composition which is non-pressure-sensitive adhesive or
low pressure-sensitive adhesive (tack free) at room temperature,
pressure-sensitive adhesive sheets made up of the foregoing
composition in the states of a sheet form, a tape form, etc., and a
sealing material, a reinforcing sheet, and a pressure-sensitive
adhesive sheet for printing using them.
BACKGROUND ART
[0002] A pressure-sensitive adhesive usually has a storage elastic
modulus [G'] at room temperature of about 1.times.10.sup.6
dyne/cm.sup.2 or lower as described in D. Satas, Adhesive Age,
31(9), 28(1988). When the storage elastic modulus of a
pressure-sensitive adhesive at room temperature is increased, the
pressure-sensitive adhesive becomes too hard and becomes
non-adhesive. This is because a micro-contact of the
pressure-sensitive adhesive and the adherend is not sufficiently
carried out in the adhesive step as in a wrapping film for foods,
namely, the wrapping films are visually (optically) adhered to each
other, but the adhesion is not exhibited.
[0003] However, because a conventional pressure-sensitive adhesive
has a softness in a sticky state having a tackiness, the
pressure-sensitive adhesive adheres quickly. But, it is not easy to
peel the pressure-sensitive adhesive adhered by lightly contacting,
and thus, the correction of the position is difficult. Also, in
processing such as cutting, punching, etc., of a pressure-sensitive
adhesive sheet, there is a problem that the processing edge is
stained with the pressure-sensitive adhesive.
[0004] If the storage elastic modulus of the pressure-sensitive
adhesive is increased to solve these problems, the adhesive
property is lowered along with the tackiness as described above,
and thus the adhesion to an adherend is difficult without an
adhesive assisting means such as heat treatment.
[0005] As described above, a pressure-sensitive adhesive which has
a high elasticity and non-pressure-sensitive adhesion or low
pressure-sensitive adhesion (tack free) capable of preventing
lowering of adhesive workability, etc., and also is excellent in
the adhesion has not yet been found.
[0006] Under such circumstances, an object of the present invention
is to provide a pressure-sensitive adhesive composition which shows
an excellent adhesion while exhibiting a high elasticity and tack
free at about room temperature, and hence can cope with the
adhesive workability and the adhesion, and a pressure-sensitive
adhesive sheet having the composition.
[0007] Also, other object of the present invention is to provide
the above-described pressure-sensitive adhesive composition and
pressure-sensitive adhesive sheets using the composition, which are
excellent in the durability, the heat resistance, etc., and further
to provide the above-described pressure-sensitive adhesive
composition and pressure-sensitive adhesive sheets using the
composition, which are also excellent in the self-adhesion in
addition to the durability such as the heat resistance, weather
resistance, etc.
[0008] Other object of the present invention is to provide the
above-described pressure-sensitive adhesive composition and
pressure-sensitive adhesive sheets using the composition, which
show a good adhesion to various adherends and are excellent in the
creep characteristics and the long-term durability and also is to
provide the above-described pressure-sensitive adhesive composition
and pressure-sensitive adhesive sheets using the composition, which
satisfy the creep resistance and the adhesion in a high temperature
range and are excellent in the shock resistance in a
low-temperature range.
[0009] Furthermore, still other object of the present invention is
to provide the above-described pressure-sensitive adhesive sheets
using a release liner not subjected to a silicone release coating
and thus suitable for computer instruments which are liable to
cause problems by the existence of a silicone, and in particular to
provide the above-described pressure-sensitive adhesive sheets
which are excellent in the releasing property of the
above-described liner and show a good adhesive strength.
[0010] Also, other object of the present invention is to provide
pressure-sensitive adhesive sheets which can be wound in a roll
form without using a release liner and are suitable for the uses
such as computer instruments as pressure-sensitive adhesive sheets
containing substantially no silicone compound.
DISCLOSURE OF THE INVENTION
[0011] The present inventors have discovered that by selecting a
specific polymer for constituting a pressure-sensitive adhesive and
crosslinking the polymer, a pressure-sensitive adhesive composition
having specific values of the storage elastic modulus and the
adhesive strength at room temperature can be obtained and the
pressure-sensitive adhesive composition shows a good adhesion while
having a high elasticity and being tack free, and also have
discovered that a pressure-sensitive adhesive composition excellent
in the self-adhesion in addition to the durability such as heat
resistance and weather resistance can be obtained by specifying the
solvent insoluble component of the polymer.
[0012] That is, the present invention provides a pressure-sensitive
composition wherein the storage elastic modulus [G'] at room
temperature is at least 2.times.10.sup.6 dyne/cm.sup.2 and the
adhesive strength at room temperature is at least 1 kg/20 mm width,
in particular, a pressure-sensitive composition comprising a
polymer having a polycarbonate structure having a repeating unit
represented by the following formula 2
[0013] wherein R represents a straight chain or branched
hydrocarbon group having from 2 to 20 carbon atoms, as the polymer
for constituting the pressure-sensitive adhesive composition, and
particularly, a pressure-sensitive adhesive composition comprising
a polyester having a weight average molecular weight of at least
10,000 synthesized from diol components indispensably containing
polycarbonate diol and dicarboxylic acid components indispensably
containing a dicarboxylic acid having an aliphatic hydrocarbon
group having from 2 to 20 carbon atoms or an alicyclic hydrocarbon
group as the molecular structure. Also, according to the present
invention, there is further provided a pressure-sensitive adhesive
composition having the above-described construction, wherein the
solvent insoluble component is from 1 to 30% by weight and the
self-adhesive strength is at least 2.0 kg/20 mm width.
[0014] Also, the present inventors have discovered that by
combining the polymer having the polycarbonate structure described
above and a specific acrylic polymer, a pressure-sensitive adhesive
composition showing good adhesion characteristics to various
adherends and being excellent in the creep characteristics and the
long-term durability can be obtained. That is, according to other
aspect of the present invention, there is provided a
pressure-sensitive adhesive composition comprising, along with the
polymer having the polycarbonate structure, an acrylic polymer
having a glass transition temperature of not higher than
-10.degree. C. in an amount of from 10 to 90% by weight of the sum
total of the above-described polymer and the acrylic polymer.
[0015] Furthermore, the present inventors have discovered that by
combining the polymer having the polycarbonate structure described
above and a specific resin, a pressure-sensitive adhesive
composition satisfying the creep resistance and the adhesion in a
high-temperature range and being excellent in the shock resistance
at a low temperature can be obtained. That is, according to still
other aspect of the present invention, there is provided a
pressure-sensitive adhesive composition comprising, along with the
polymer having the polycarbonate structure, a resin having a
softening point of at least 80.degree. C. in an amount of from 10
to 50% by weight of the sum total of the above-described polymer
and the resin.
[0016] Moreover, the present invention can further provide
pressure-sensitive adhesive sheets having the above-described
pressure-sensitive adhesive compositions of various constitutions
formed into a sheet form, a tape form, etc., that is,
pressure-sensitive adhesive sheets having a layer composed of each
of the above-described pressure-sensitive adhesive compositions
having the various constitutions. In such pressure-sensitive
adhesive sheets, a release liner is generally stuck to the surface
of the pressure-sensitive adhesive layer thereof. As the release
liner, the present inventors have discovered that a release liner
made up of a polyethylene film, a polypropylene film, etc., which
is not subjected to a silicone release coating, can be used, that
is, a pressure-sensitive adhesive sheet exhibiting excellent
releasing property of the release liner and having good adhesive
strength can be obtained because. of the characteristics of the
pressure-sensitive adhesive composition. Accordingly, it has been
discovered that pressure-sensitive adhesive sheets suitable for
computer instruments, etc., which are liable to cause problems by
the presence of a silicone, can be provided.
[0017] That is, according to other aspect of the present invention,
there are provided pressure-sensitive adhesive sheets each having
the layer made up of each of the above-described pressure-sensitive
adhesive compositions of various constitutions and having stuck to
the surface of the pressure-sensitive adhesive layer a release
liner which is not subjected to a silicone release coating and, in
particular, there are provided the pressure-sensitive adhesive
sheets wherein the above-described release liner, which is not
subjected to a silicone release coating, is a polyolefinic film
composed of polyethylene, polypropylene, an ethylene-propylene
copolymer or a mixture thereof, or a film the surface of which is
processed with the polyolefin as described above, and also the
releasing strength of the release liner is 200 g/50 mm width or
lower.
[0018] Also, the present inventors have discovered that in the case
of forming each of the above-described pressure-sensitive adhesive
compositions of various constitutions on one surface of a base
material, when at least the back side of the base material is
constituted with a polyolef in such as polyethylene, polypropylene,
etc., a pressure-sensitive adhesive sheet, which has a good
releasing property between the layer made up of the
pressure-sensitive composition and the back surface of the base
material and thus can be wound in a roll form without inserting a
release liner, can be obtained. That is, because according to the
pressure-sensitive adhesive sheets, they do not have release liners
and it is unnecessary to apply a silicone release coating to the
back surface of each base material of them, the pressure-sensitive
adhesive sheets of the present invention can be used for computer
instruments, etc., which cause a problem by the presence of
silicone, as pressure-sensitive adhesive sheets substantially
containing no silicone compound.
[0019] In the pressure-sensitive adhesive composition of the
present invention, the storage elastic modulus [G'] at room
temperature is 2.times.10.sup.6 dyne/cm.sup.2 or higher, preferably
3.times.10.sup.6 dyne/cm.sup.2 or higher, particularly preferably
5.times.10.sup.6 or higher, and usually 5.times.10.sup.7
dyne/cm.sup.2 or lower, and the pressure-sensitive adhesive
composition does not show a high tackiness as a pressure-sensitive
adhesive and scarcely adhere in a short time of about a few
seconds. Accordingly, if it is a short time after adhesion, the
pressure-sensitive adhesive composition can be peeled once and then
adhered again, and the stuck position can be corrected without
injuring an adherend. Also, in cutting the pressure-sensitive
adhesive sheet, the pressure-sensitive adhesive does not stick to
the cutting edge and does not stain the edge, because the
pressure-sensitive adhesive does not adhere in a short time.
[0020] Also, although the pressure-sensitive adhesive composition
of the present invention has a high elasticity and is tack free as
described above, the pressure-sensitive adhesive composition has an
adhesive strength at room temperature of at least 1 kg/20 mm width,
preferably at least 1.5 kg/20 mm width, and usually 10 kg/20 mm
width or lower and is provided with the unique and useful
characteristics of showing a high adhesive strength without need of
complicated step such as a heat treatment. An excellent effect of
satisfying both the adhesive workability and the adhesion, which is
difficult in conventional pressure-sensitive adhesive compositions,
can be obtained by the characteristics.
[0021] In such a pressure-sensitive adhesive composition, it is
preferred that the storage elastic modulus [G'] at -30.degree. C.
is 3.times.10.sup.7 dyne/cm.sup.2 or lower, preferably
2.times.10.sup.7 dyne/cm.sup.2 or lower, and usually
5.times.10.sup.6 dyne/cm.sup.2 or higher, and in this case, the
effect that the pressure-sensitive adhesive composition is
excellent in the shock resistance at a low temperature can be
obtained. Also, it is preferred that the storage elastic modulus
[G'] at 80.degree. C. is 1.times.10.sup.6 dyne/cm.sup.2 or higher,
preferably 3.times.10.sup.6 dyne/cm.sup.2 or higher, and usually
5.times.10.sup.7 dyne/cm.sup.2 or lower, and in this case, the
pressure-sensitive adhesive composition shows a high cohesive force
at a temperature as high as 80.degree. C. and excellent
characteristics are obtained together with the adhesive strength
and the holding power.
[0022] The pressure-sensitive adhesive composition of the present
invention has no particular restriction on the composition, as long
as the composition has the above-described storage elastic modulus
[G'] and the above-described adhesive strength, but, preferably
used is a composition which is obtained by adding a crosslinking
agent such as a polycyanate compound, etc., to a polymer for
constituting the pressure-sensitive adhesive and effecting a
crosslinking treatment and has the storage elastic modulus [G'] and
the adhesive strength specified above as a result of the selection
of the polymer, the extent of the crosslinking treatment and the
like. With respect to the polymer for constituting the
pressure-sensitive adhesive, a polymer having the repeating unit
represented by the following formula is preferred as the polymer
having a polycarbonate structure; 3
[0023] wherein R represents a straight chain or branched
hydrocarbon group having from 2 to 20 carbon atoms.
[0024] The polymer includes a polyester synthesized from a
polycarbonate diol (or the derivative thereof) and a dicarboxylic
acid (or the derivative thereof), the polyester synthesized from a
polycarbonate dicarboxylic acid and a diol, a polyurethane
synthesized from a polycarbonate diol and a diisocyanate, etc., and
in these polymers, the polyester synthesized from a polycarbonate
diol and a dicarboxylic acid is preferred.
[0025] The polyester of this kind has a weight average molecular
wight of at least 10,000, preferably at least 30,000, and
particularly preferably at least 50,000 (usually not more than
300,000) synthesized from diol components indispensably containing
a polycarbonate diol and dicarboxylic acid components indispensably
containing a dicarboxylic acid having an aliphatic hydrocarbon
having from 2 to 20 carbon atoms or an alicyclic hydrocarbon as the
molecular structure.
[0026] The polycarbonate diol used in this case is a diol having
the repeating unit represented by the following formula 4
[0027] wherein R represents a straight chain or branched
hydrocarbon group having from 2 to 20 carbon atom, and the number
average molecular weight of the diol is at least 400, preferably at
least 900 (usually not more than 10,000).
[0028] Such a polycarbonate diol includes
polyhexamethylenecarbonate diol, poly(3-methylpentenecarbonate)
diol, polypropylenecarbonate diol, etc., a mixture thereof, and a
copolymer thereof. As commercially available products of the
polycarbonate diol, there are "PLACCEL CD205PL", "PLACCEL CD208PL",
"PLACCEL CD210PL", "PLACCEL CD220PL", "PLACCEL CD205", "PLACCEL
CD208", "PLACCEL CD210", "PLACCEL CD220", "PLACCEL CD205HL",
"PLACCEL CD208HL", "PLACCEL CD210HL", "PLACCEL CD22OHL", etc.,
trade names, made by DAICEL CHEMICAL INDUSTRIES, LTD.
[0029] As the diol components, in addition to the above-described
polycarbonate diol, if necessary, other components such as straight
chain diol components and branched diol components (e.g., ethylene
glycol, propylene glycol, butane diol, hexane diol, octane diol,
decane diol, and octadecane diol) may be used in combination. It is
preferred that the used amount of these other diol(s) is not more
than 50% by weight, and preferably not more than 30% by weight to
the total amount of the diol components. Also, a small amount of
polyol component(s) of a three functional or higher may be added to
increase the molecular weight of the polymer.
[0030] Also, the dicarboxylic acid component has an aliphatic
hydrocarbon group having from 2 to 20 carbon atoms or an alicyclic
hydrocarbon group and the aforesaid hydrocarbon group may be a
straight chain one or a branched one. Specifically, there are
succinic acid, methylsuccinic acid, adipic acid, pimelic acid,
azelaic acid, sebacic acid, 1,12-dodecane diacid, 1,14-tetradecane
diacid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic
acid, the acid anhydrides and the lower alkyl esters of these
acids, etc.
[0031] As the dicarboxylic acid, it is preferred that the
dicarboxylic acid having the aliphatic hydrocarbon group having
from 2 to 20 carbon atoms or the alicyclic hydrocarbon group as the
molecular structure is used singly but as the case may be a
dicarboxylic acid having an aromatic hydrocarbon group as the
molecular structure may be used together with the aforesaid
dicarboxylic acid. It is better that the used amount of the
dicarboxylic acid having the aromatic hydrocarbon group as the
molecular structure is 50% by weight or lower, and particularly
preferably an amount as small as 30% by weight or lower. Also, for
the purpose of increasing the molecular weight of the polyester to
be synthesized, a small amount of a tri-functional or higher
functional carboxylic acid component can be added thereto.
[0032] The polyester is obtained by subjecting the diol component
and the dicarboxylic acid component described above to an
esterification reaction in the absence or presence of an
appropriate catalyst according to an ordinary method. In this case,
it is preferred that the diol component and the diarboxylic acid
component are subjected to an equimolar reaction, but, the reaction
may be carried out using either of them in an excessive amount in
order to accelerate the esterification reaction. It is desirable
that the polyester thus obtained has the above-described molecular
weight. This is because if the molecular weight thereof is too low,
the highly crosslinked pressure-sensitive adhesive has a high
crosslinking density and thus has a very hard property, and
contrary, the attempt of lowering the crosslinking density is
undesirable in the heat resistance, etc., owing to the low
molecular weight of the uncrosslinked components.
[0033] In the present invention, the pressure-sensitive adhesive
composition, wherein the storage elastic modulus [G'] at room
temperature and the adhesive strength become the above-described
ranges, is formed by usually subjecting such a polymer having the
polycarbonate structure, such as the polyester, to a crosslinking
treatment by a proper means. In this case, the crosslinking means
may be arbitrary, but a general method comprises using a
poly-functional compound such as a polyisocyanate compound, an
epoxy compound, an aziridine compound, a metal chelate compound,
and a metal alkoxide compound as a crosslinking agent and
crosslinking the polymer by reacting the polymer (the hydroxy group
and the carboxyl group contained therein) and the poly-functional
compound. As the poly-functional compound, a polyisocyanate
compound is particularly preferred.
[0034] The polyisocyanate compound includes lower aliphatic
polyisocyanates such as ethylene diisocyanate, butylene
diisocyanate, hexamethylene diisocyanate, etc.; alicyclic
polyisocyanates such as cyclopentylene diisocyanate, cyclo-hexylene
diisocyanate, isophorone diisocyanate, etc.; aromatic
polyisocyanate such as 2,4-tolylene diisocyanate,
4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, etc.
[0035] As other polyisocyanate compound, the tolylene diisocyanate
addition product of trimethylolpropane (Coronate L, trade name,
made by Nippon Polyurethane Industry Co., Ltd.), the hexamethylene
diisocyanate addition product of trimethylolpropane (Coronate HL,
trade name, made by Nippon Polyurethane Industry Co., Ltd.), etc.,
are also used.
[0036] These polyfunctional compounds are used singly or as a
mixture of two or more. The used amount thereof is properly
selected according to the balance with the polymer to be
crosslinked and the use application of the pressure-sensitive
adhesive composition but in general, it is better to carry out the
crosslinking treatment by compounding 0.5 part by weight or more,
and preferably from about 1 to 5 parts by weight of the
polyfunctional compound(s) per 100 parts by weight of the polymer
having the polycarbonate structure. A pressure-sensitive adhesive
composition in which the content of the solvent-insoluble component
of the polymer is from 10 to 90% by weight, preferably from 15 to
80% by weight, and more preferably from 20 to 70% by weight can be
obtained by the crosslinking treatment. If the content of the
solvent-insoluble component of the polymer is too small, the
insufficient cohesive force of the pressure-sensitive adhesive is
exhibited and the sufficient modulus of elasticity, heat
resistance, and durability can not be obtained.
[0037] As other crosslinking means, there is a method of
compounding a polyfunctional monomer as a crosslinking agent with
the polymer and crosslinking the polymer by electron rays, etc. The
polyfunctional monomer includes ethylene glycol (meth)acrylate,
pentaerithritol tri(meth)acrylate, tetramethylolmethane
tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. It
is better that the used amount of the polyfunctional monomer is
from 1 to 5 parts by weight, and preferably from 2 to 4 parts by
weight per 100 parts of the above-described polymer such that the
solvent-insoluble component of the polymer after crosslinking by
electron rays, etc., is the value falling within the range
described above.
[0038] The pressure-sensitive adhesive composition of the present
invention is formed by using the above-described polymer having the
polycarbonate structure as the base polymer and crosslinking the
polymer usually by the means described above and the composition
may be compounded with a conventionally known tackifier and also
can arbitrarily contain various additives such as an inorganic or
organic filler, a metal powder, a powder of a pigment, etc., a
granular material, a foil-form material, an antioxidant, a
plasticizer, etc.
[0039] The pressure-sensitive adhesive composition of the present
invention shows a high adhesive strength while having a high
modulus of elasticity and being tack free at room temperature, and
further when the solvent-insoluble component is adjusted in the
range of from 1 to 30% by weight, and preferably from 2 to 15% by
weight by the crosslinking treatment of the polymer, the
pressure-sensitive adhesive composition shows an excellent
self-adhesion in addition to the durability such as the heat
resistance, or the weather resistance. That is, the present
invention can provide a pressure-sensitive adhesive composition
having a self-adhesive strength of 2.0 kg/20 mm width or higher,
and preferably from 2.5 to 10 kg/20 mm width. In this case, if the
solvent-insoluble component of the polymer described above is less
than 1% by weight, the pressure-sensitive adhesive composition is
inferior in the durability such as the heat resistance, the weather
resistance, etc., and if the solvent-insoluble component is more
than 30% by weight, the high self-adhesive strength as described
above is hard to be obtained.
[0040] In addition, hitherto, pressure-sensitive adhesives prepared
by compounding a tackifier, a softening agent, etc., with a natural
rubber, a synthetic rubber, etc., are known as a pressure-sensitive
adhesive having a self-adhesion for bundling fresh vegetables or
arranged flowers as disclosed in JP-A-54-96539 and JP-A-56-26968
(the term "JP-A" as used herein meas an "unexamined published
Japanese patent application"). However, because these
pressure-sensitive adhesives are inferior in the weather resistance
and the heat resistance, they have never been used for uses being
used outdoors and used of requiring a reliability over a long
period of time as industrial materials. Also, because these
pressure-sensitive adhesives have a tackiness (pressure-sensitive
adhesive property), there is a problem that the pressure-sensitive
adhesive attaches to the hand and finger, articles, etc., before
and after bounding. On the other hand, the pressure-sensitive
adhesive composition of the present invention does not cause such a
problem.
[0041] Furthermore, removing is difficult when removing after
self-adhesion is required, and cutting of the pressure-sensitive
adhesive tape is needed to release the bundling. In the cutting,
there is a possibility of damaging the bundled article.
[0042] In the pressure-sensitive composition of the present
invention, the polymer having the specific polycarbonate structure
is contained as the main component and by crosslinking the polymer
to a specific level, the pressure-sensitive adhesive composition
does not substantially show a tackiness (i.e., show non-tackiness
or slight tackiness at room temperature) but has an excellent
self-adhesion and can be removed.
[0043] That is, the present invention provides a pressure-sensitive
adhesive composition comprising, as the main component, a polymer
having a polycarbonate structure having a repeating unit
represented by the following formula 5
[0044] wherein R represents a straight chain or branched
hydrocarbon group having from 2 to 20 carbon atoms, wherein the
self-adhesive strength is at least 100 g/20 mm width and the
adhesive strength is not higher than 2,000 g/20 mm width, and in
particular, the above-described pressure-sensitive adhesive
composition in which the aforesaid polymer is crosslinked and the
solvent-insoluble component is from 60 to 95% by weight.
[0045] Furthermore, the present invention provides a
pressure-sensitive adhesive sheet comprising a base material having
on one surface or both surfaces thereof the layer made up of the
above-described pressure-sensitive adhesive composition.
[0046] In the present invention, a pressure-sensitive adhesive
composition which does not substantially show a tackiness (i.e.,
show non-tackiness or slight tackiness at room temperature), but
has a good self-adhesion and is excellent in the removability is
obtained by crosslinking such a polymer having the polycarbonate
structure, such as a polyester, to a specific level. In this case,
the extent of crosslinking is preferably such that the
solvent-insoluble component is in the range of from 60 to 95% by
weight, and more preferably from 65 to 90% by weight. If the
solvent-insoluble component is less than 60% by weight, a
sufficient removability is not obtained and if the
solvent-insoluble component is more than 95% by weight, the
self-adhesive strength is lowered. Thus, both cases are
undesirable.
[0047] In the crosslinking method, the crosslinking agent is the
same as described above and these crosslinking agents can be used
singly or as a mixture of two or more. The used amount thereof is
properly selected according to the balance with the polymer to be
crosslinked. In general, it is better that the ratio of the
above-described crosslinking agent becomes from about 2 to 10 parts
by weight to 100 parts by weight of the polymer. The use of the
crosslinking agent in such a ratio enables a pressure-sensitive
adhesive composition having a solvent-insoluble component falling
within the above-described range.
[0048] As other crosslinking agent, a method of adding the
polyfunctional monomer as described above to the polymer as a
substantial crosslinking agent and crosslinking the polymer by
electron beam, etc., may be employed. The used amount of the
polyfunctional monomer is properly selected according to the
balance with the polymer to be crosslinked and further the use
application of the pressure-sensitive adhesive composition. In
general, it is better that the ratio of the polyfunctional monomer
is at least 3 part by weight (usually up to about 10 parts by
weight) to 100 parts by weight of the polymer, and by using the
polyfunctional monomer in such a proportion, the pressure-sensitive
adhesive composition having a solvent-insoluble component falling
within the above-described range can be obtained.
[0049] The pressure-sensitive adhesive composition of the present
invention is prepared by subjecting the above-described polymer to
the crosslinking treatment as described above and has a
self-adhesive strength and a removability such that the
self-adhesive strength is 100 g/20 mm width or higher, preferably
150 g/20 mm width or higher, and more preferably 200 g/20 mm width
or higher (usually up to 1,500 g/20 mm width) and the adhesive
strength is 2,000 g/20 mm width or lower, preferably 1,800 g/20 mm
width or lower, and more preferably 1,500 g/20 mm width or lower
(usually up to 100 g/20 mm width).
[0050] If the self-adhesive strength is less than 100 g/20 mm
width, the reliability of the unity or adhere of articles is
inferior and if the adhesive strength is higher than 2000 g/20 mm
width, the removing is difficult.
[0051] The term "self-adhesive strength" in the specification
indicates the releasing strength at the initial stage after the
pressure-sensitive adhesive surfaces are stuck to each other, and
on the other hand, the term "adhesive strength" indicates the
above-described releasing strength (self-adhesive strength) after
allowing to stand for one day as in the working examples described
later.
[0052] Also, in the present invention, by, along with the polymer
having the polycarbonate structure, using an acrylic polymer having
a glass transition temperature of -10.degree. C. or lower in a
ratio of from 10 to 90% by weight, and preferably from 15 to 85% by
weight based on the sum total of the acrylic polymer and the
above-described polymer, a pressure-sensitive adhesive composition
showing good adhesive property to various adherends in addition to
the above-described characteristics and being excellent in the
creep characteristics and the long-term durability can be
obtained.
[0053] Hitherto, an acrylic pressure-sensitive adhesive not
containing a tackifier is poor in the adhesive property to
plastics, while an acrylic or natural rubber series
pressure-sensitive adhesive containing a tackifier has relatively
good adhesive property to plastics, but has a problem in the creep
characteristics and the long-term durability. On the other hand, in
the pressure-sensitive adhesive composition of the present
invention, such problems are avoided, and a pressure-sensitive
adhesive excellent in the adhesive property to various adherends,
in particular, plastics such as polycarbonate, acrylic resins,
etc., and also excellent in the creep characteristics and the
long-term durability can be provided.
[0054] The acrylic polymer to be used herein is a polymer made from
monomers containing from 50 to 100% by weight of a (meth)acrylate
having an alkyl group having from 4 to 14 carbon atoms, and the
acrylic polymer having a glass transition temperature of
-10.degree. C. or lower, and particularly -15.degree. C. or lower
(usually up to about -90.degree. C.) is preferably used. If the
glass transition point is higher than -10.degree. C., the
pressure-sensitive adhesive composition is undesirably inferior in
the initial adhesive strength.
[0055] The (meth)acrylate having an alkyl group having from 4 to 14
carbon atoms includes the alkyl esters of (meth)acrylic acid having
an alkyl group such as butyl, isobutyl, isoamyl, hexyl, heptyl,
2-ethylhexyl, iso-octyl, iso-nonyl, lauryl, or iso-myristyl.
[0056] In the case of using such an acrylic polymer in combination,
it is general to separately synthesizing the acrylic polymer and
the polymer having the polycarbonate structure, and then mixing
both the polymers at a solution state or bulky state to prepare a
pressure-sensitive adhesive composition. However, as the case may
be, the pressure-sensitive adhesive composition may be prepared by
a method of effecting polymerization for the preparation of one
polymer in another polymer or a method of simultaneously effecting
polymerization for both polymers.
[0057] In these preparation methods, the used amount of the
above-described acrylic polymer is such that the proportion of the
acrylic polymer based on the sum total of the acrylic polymer and
the polymer having the polycarbonate structure falls within the
range described above. If the content of the acrylic polymer is
less than 10% by weight, the initial adhesive property is lowered.
On the other hand, if the content is more than 90% by weight, the
adhesive property to plastics is lowered. Also, one or both of the
aforesaid acrylic polymer and the polymer having the polycarbonate
structure are subjected to the crosslinking treatment by the method
described above and in this case, it is better that the
solvent-insoluble component in the whole polymers falls within the
range of from 10 to 90% by weight, preferably from 15 to 85% by
weight, and more preferably from 20 to 80% by weight. If the
content of the solvent-insoluble components is low, the creep
characteristics and the long-term durability are inferior, while if
the content is too high, the initial adhesive property is inferior.
Thus, both cases are undesirable.
[0058] Furthermore, in the present invention, by using a resin
having a softening of at least 80.degree. C., together with the
polymer having the polycarbonate structure, in a ratio of from 10
to 50% by weight, preferably from 13 to 45% by weight, and more
preferably from 15 to 35% by weight of the sum total of the resin
and the polymer, a pressure-sensitive adhesive composition
satisfying the creep resistance and the adhesive property in a
high-temperature range in addition to the above-described
characteristics and also being excellent in the shock resistance at
a low temperature can be obtained.
[0059] Hitherto, a pressure-sensitive adhesive composition
containing added therein a heat-melting resin is known as described
in JP-B-56-13040 (the term "JP-B" as used herein means an "examined
published Japanese patent application"). The pressure-sensitive
adhesive composition has advantages that the treatment work is
simple and a heat resistance is not required for an adherend as
compared with a heat-curing type requiring a heat treatment of
100.degree. C. or higher but on the other hand, there is a problem
in obtaining the creep resistance and the adhesive property in a
high-temperature range.
[0060] Also, in JP-B-2-50146, a product obtained by adding a
heat-melting resin in an acrylic graft polymer having a polymer of
a high glass transition temperature at the side chain thereof is
disclosed. The product satisfies the creep resistance and the
adhesive property at a high-temperature range, but has a problem
that it has poor shock resistance at a low temperature.
[0061] On the other hand, the pressure-sensitive adhesive
composition of the present invention described above does not have
such a problem, and a heat pressure-sensitive adhesive composition
satisfying the creep resistance and the adhesive property at a
high-temperature range and being excellent in the shock resistance
at a low temperature can be provided.
[0062] The resin used in this case of the present invention has a
softening point of 80.degree. C. or higher, preferably 90.degree.
C. or higher, and more preferably 100.degree. C. or higher and
usually not higher than 150.degree. C. The softening point of lower
than 80.degree. C. is undesirable, since the creep resistance and
the adhesive strength at a high temperature are lowered.
[0063] As the kind of the resin, there are a terpene series resin,
a rosin series resin, an alkylphenol series resin, a terpene phenol
series resin, a rosin phenol series resin, a coumarone-indene
series resin, an aromatic petroleum series resin, an aliphatic
petroleum series resin, etc.
[0064] If the ratio of the resin of this kind is less than 10% by
weight of the sum total of the resin and the polymer having the
polycarbonate structure, the shock resistance at a low temperature
is inferior.
[0065] Also, it is better that the solvent-insoluble component of
the polymer containing the resin after the crosslinking treatment
is in the range of from 10 to 90% by weight, preferably from 15 to
85% by weight, and more preferably from 20 to 80% by weight. If the
content of the solvent-insoluble component is too low, the
durability is inferior and if the content is too high, the adhesive
property is inferior. Thus, both cases are not desirable.
[0066] The pressure-sensitive adhesive sheets of the present
invention are a sheet-form or tape-form formed by the
pressure-sensitive adhesive compositions of the various
constitutions described above. That is, the pressure-sensitive
adhesive sheets have at least a layer composed of the
pressure-sensitive adhesive composition described above. The
pressure-sensitive adhesive sheets include a so-called base
material-less double faced pressure-sensitive adhesive sheet formed
by firstly coating the layer of the above-described
pressure-sensitive adhesive composition on a release liner so as to
provide a dry thickness of usually about from 10 to 150 .mu.m and,
if necessary, sticking a release liner to the surface of the layer.
In this case, in order to improve the adhesive characteristics, a
multilayer structure may be formed utilizing other
pressure-sensitive adhesive compositions.
[0067] Also, as the more general pressure-sensitive adhesive sheet,
a base material-attached single faced or double faced
pressure-sensitive adhesive sheet can be formed by using a base
material composed of a plastic film such as a polyester film, etc.;
a porous material such as a paper, a non-woven fabric, etc.; a
metal foil, etc., coating the layer composed of the above-described
pressure-sensitive adhesive composition on one surface or both
surfaces of the base material at a dry thickness of usually from
about 10 to 150 .mu.m per one surface such that the base material
carries the pressure-sensitive adhesive layer, and sticking a
release liner on the surface(s) of the pressure-sensitive adhesive
layer(s). In this case, to improve the adhesive characteristics, a
multilayer structure may be employed by utilizing other
pressure-sensitive adhesive composition.
[0068] In addition, in the base material-attached
pressure-sensitive adhesive sheets and the above-described base
material-less double faced pressure-sensitive adhesive sheets, the
crosslinking treatment to the polymer having the polycarbonate
structure, etc., can be properly applied during the production step
of the above-described pressure-sensitive adhesive sheets or after
the production step.
[0069] In the present invention, as the release liner to be stuck
to the pressure-sensitive adhesive layer surface, a release liner
made up of a polyethylene film, a polypropylene film, etc., which
is not subjected to a silicone release coating, can be used. That
is, even when such a release liner is used, a very good releasing
property such that the releasing strength of the liner is 200 g/50
mm width or lower, preferably 100 g/50 mm width or lower, and more
preferably 50 g/50 mm width or lower (usually up to 1 g/50 mm
width) can be obtained, and further the good adhesive strength
described above can be maintained.
[0070] In conventional acrylic series or rubber series
pressure-sensitive adhesives, when a polyethylene film or a
polypropylene film is used as a release liner, the releasing
strength is 500 g/50 mm width or higher to lower the releasing
workability, whereby it is inevitable to use a silicone-treated
release liner. In the present invention, using a release liner
which is not subjected to a silicone release coating, the releasing
strength thereof can be set to 200 g/50 mm width or lower, and the
above-described liner can be easily removed and the
pressure-sensitive adhesive sheets of the present invention can be
handled in the same manner as the use of ordinary
pressure-sensitive adhesive tapes having silicone-treated release
liners. For this reason, the change of the apparatus, the working
process, etc., accompanied by the change of the silicone-treated
release liner to the above-described release liner is
unnecessary.
[0071] As described above, in the pressure-sensitive adhesive
sheets of the present invention, by using a polyethylene film, a
polypropylene film, etc., as the release liner, the production of
the pressure-sensitive adhesive sheets containing no silicone is
possible and as the result thereof, the pressure-sensitive adhesive
sheets suitable for computer instruments which are liable to cause
a problem by the presence of a silicone can be provided.
Furthermore, when the release liner is made up of a simple film
material such as polyethylene or polypropylene, the effect of
providing excellent recycling property of plastics, which is
regarded as a problem remarkably in these days, can be
obtained.
[0072] The release liner not subjected to a silicone release
coating, which can be used in the present invention, includes
polyolef in series films made up of polyethylene, polypropylene, an
ethylene-propylene copolymer (block or random copolymer), or a
mixture of them or films the surface of which is processed with the
above-described polyolefins, that is, polyethylene, polypropylene,
an ethylene-propylene copolymer (block or random copolymer) or a
mixture of them. The film the surface of which is processed with
the polyolefin described above includes, for example, a laminate of
the above-described polyolefin series film and papers or other
films.
[0073] In the present invention, as the pressure-sensitive adhesive
sheet not using such a release liner, a pressure-sensitive adhesive
sheet comprising a base material having formed on one surface
thereof the layer being composed of the above-described
pressure-sensitive adhesive composition and having the thickness
described above and having at least the back side thereof
constituted with a polyolefin such as polyethylene, polypropylene,
an ethylene-propylene copolymer (block or random copolymer) or a
mixture thereof can be also obtained.
[0074] The feature of the pressure-sensitive adhesive sheets of
this kind is that the back side of the base material is not
subjected to a silicone release coating, but the releasing property
between the layer composed of the pressure-sensitive adhesive
composition and the back surface of the base material is good, and
thus, the pressure-sensitive adhesive sheet can be wound in a roll
form without inserting a release liner. As described above, because
the pressure-sensitive adhesive sheet does not have a release liner
and it is unnecessary to apply a releasing coating with a silicone
compound to the back surface of the base material, the
pressure-sensitive adhesive sheet of the present invention can be
advantageously used for computer instruments as a
pressure-sensitive adhesive sheet substantially containing no
silicone compound. In addition, if the anchoring property of the
layer composed of the pressure-sensitive adhesive composition and
the base material is ensured, not only the back side of the base
material but also the whole base material may be constituted with
the polyolefin described above.
[0075] Second, the present invention provides a sealing material
comprising a sealing base material having formed thereon the layer
of the pressure-sensitive adhesive composition, which is used as an
adhesive seal for constituting parts in electron instruments
particularly avoiding a siloxane gas, such as mainly a hard disc
drive (hereinafter referred to as HDD), a personal computer, a word
processor, personal digital assistance (portable information
instrument for person; hereinafter referred to as PDA), a portable
telephone, etc.
[0076] The constituting parts in HDD, a personal computer, a word
processor, PDA, a portable telephone, etc., are various and as one
of the connecting means of these parts, a method of using a
pressure-sensitive adhesive-processed product such as a
pressure-sensitive adhesive tape is known. In particular, in the
housing constructing step of HDD, to secure the airtightness, a
pressure-sensitive adhesive-processed sealing material, that is, a
sealing material (packing material) prepared by forming a layer of
a pressure-sensitive adhesive composition on a foamed base material
or a base material having a moisture-proofing effect is used. For
the pressure-sensitive adhesive composition of the sealing material
of this kind, it is desired to show a high adhesive property and
cohesive property, and recently, performance such as a low volatile
property is also required.
[0077] Now, in such a pressure-sensitive adhesive-processed sealing
material, a release liner is usually stuck to the surface of the
pressure-sensitive adhesive layer to protect the surface of the
pressure-sensitive adhesive layer and to improve the handling
property at storage and at use. Also, as the case may be, the back
surface of the sealing base material composed of a foamed base
material or a base material having a moisture-proof effect is
subjected to a releasing coating to improve the releasing property
between the surface of the pressure-sensitive adhesive layer and
the back surface of the base material, whereby the sealing material
is wound in a roll form without inserting a release liner.
[0078] On the other hand, the conventional sealing materials are
designed such that a good adhesive property is secured, i.e.,
almost all sealing materials have a release liner subjected to a
silicone release coating which has a low adhesive property or the
back surface is subjected to a silicone release coating to improve
releasing property with the back surface thereof. This causes the
following problem.
[0079] That is, in the sealing materials of this kind, a phenomenon
that a part of a silicone compound existing in the release liner or
at the back side of the sealing base material transfers to the
surface of the layer of the pressure-sensitive adhesive composition
occurs. The phenomenon is almost insignificant in the case of a
usual sealing material, but in the case where the sealing material
is used in the state of being closed in the inside of HDD, etc., it
becomes the cause of generating a siloxane gas, which results in
causing the corrosion of the inside of HDD and causing erroneous
actions.
[0080] Under such circumstances, other object of the present
invention is to provide a sealing material being excellent in the
releasing property from a release liner or the back surface of the
base material, showing a good adhesive strength, and having a high
sealing effect by using a release liner which is not subjected to a
silicone release coating and a sealing base material the back
surface of which is not subjected to a silicone release
coating.
[0081] As the result of various investigations, the present
inventors have found that by providing the pressure-sensitive
adhesive composition comprising the specific polymer having the
polycarbonate structure on a sealing base material, a release liner
(for example, composed of a polyethylene film) which is not
subjected to a silicone release coating and a sealing base
material- having a back side (for example, one constituted with
polyethylene) which is not subjected to a silicone release coating
can be used, and a sealing material having excellent releasing
property with the release liner or the back surface of the base
material, showing a good adhesive property, and having a high
sealing effect as the desired object can be obtained, and the
problems of causing the corrosion of the inside, etc., of HDD and
the erroneous actions by the generation of a siloxane gas are
avoided by the sealing material, and have accomplished the present
invention.
[0082] That is, according to still other aspect of the present
invention, there is provided a sealing material comprising a
sealing base material composed of a foamed base material or a base
material having a moisture proof effect having thereon a layer
composed of a pressure-sensitive adhesive composition comprising a
polymer of a polycarbonate structure having a repeating unit
represented by the following formula as described above; 6
[0083] wherein R represents a straight chain or branched
hydrocarbon group having from 2 to 20 carbon atoms.
[0084] In particular, the present invention provides a sealing base
material wherein a release liner, which is not subjected to a
silicone release coating, is stuck to the surface of the
pressure-sensitive adhesive layer or the back side thereof is not
subjected to a silicone release coating, and the sealing material
is wound in a roll form without inserting a release liner and
mainly provides the above-described sealing material as a
connecting material for HDD, etc.
[0085] As the sealing base material to be used in this invention,
known various materials can be used as long as the materials are
provided with the sealing function as the desired purpose and do
not substantially contain a silicone compound in the components of
the materials. The typical sealing material is a sheet-form
material or a foamed material of a synthetic resin or a synthetic
rubber, such as polyurethane, a styrene-butadiene copolymer rubber
(hereinafter referred to as SBR) or a material having an elastic
effect made up of the laminate of these synthetic resin films. The
thickness of the sealing material differs according to the form of
the material, i.e., whether the material is a sheet-form material,
a foamed material, or a laminate, but is generally from about 0.3
to 2.0 mm.
[0086] Another sealing material is a metal foil such as an aluminum
foil, a fluorine resin film or a material having a moisture proof
effect made up of a composite material obtained by forming a metal
layer such as aluminum, etc., on a synthetic resin film such as a
polyester film, etc., (laminating the metal foil or vapor
depositing the metal on the synthetic resin film) or a composite
material obtained by coating a fluorine resin layer on the
synthetic resin film as described above. The thickness of the
sealing material largely differs depending on whether the material
is the metal foil, the fluorine resin film, or the laminate, but is
preferably from about 10 to 200 .mu.m.
[0087] In addition, the fluorine resin constituting the fluorine
resin film and the fluorine resin layer includes
polytetrafluoroethylene (PTFE), a
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), a
tetrafluoroethylene-hexafluoroporpylene copolymer (FEP), an
ethylene-tetrafluoroethylene copolymer (E/TFE), polyvinylidene
fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), an
ethylene-chlorotrifluoroe- thylene copolymer (E/CTFE), a
tetrafluoroethylene-perfluorodimethyldioxol copolymer (TEF/PDD),
polyvinyl fluoride (PVF), etc.
[0088] The sealing material of the present invention is prepared by
coating the layer composed of the above-described
pressure-sensitive adhesive composition on the sealing base
material as described above such that the layer has a dry thickness
of usually from about 10 to 150 .mu.m. The layer of the
pressure-sensitive adhesive composition may be formed on one
surface of the base material but, if necessary, may be formed on
both surfaces thereof. Also, for improving the adhesive
characteristics, a multilayer structure may be employed using other
pressure-sensitive adhesive composition.
[0089] In such a sealing material, a release liner, which is not
subjected to a silicone release coating, is usually stuck to the
surface of the pressure-sensitive adhesive surface, that is, the
surface of the layer composed of the pressure-sensitive adhesive
composition. The release liner includes a polyolefin series film
made up of polyethylene, polypropylene, an ethylene-propylene
copolymer (block or random copolymer) or a mixture thereof and a
film processed with the foregoing polyolefin, i.e., polyethylene,
polypropylene, an ethylene-propylene copolymer (block or random
copolymer) or a mixture thereof and the latter film the surface of
which is processed also includes a laminate of the above-described
polyolef in series film and papers or other films. The thickness of
the release liner which is not subjected to a silicone release
coating is usually from about 20 to 200 .mu.m.
[0090] The sealing material of the present invention thus
constituted is excellent in the releasing property and shows a
large adhesive strength such that the releasing strength of the
release liner is 200 g/50 mm width or lower, preferably 100 g/50 mm
width or lower, and more preferably 50 g/50 mm width or lower
(usually up to 1 g/50 mm width) and the adhesive strength is 1
kg/20 mm width or higher and preferably 1.5 kg/20 mm width or
higher (usually up to 10 kg/20 mm width).
[0091] As described above, the sealing material of the present
invention contains no silicone by utilizing a polyethylene film, a
polypropylene film, etc., as the release liner and thus is
particularly useful as a connecting material for HDD, etc., causing
a problem by the generation of a siloxane gas. Also, when the
release liner is made up of a simple film material such as
polyethylene, polypropylene, etc., the sealing material is also
excellent in the recycling property of plastics, which is
particularly regarded as a problem recently.
[0092] Also, when in general acrylic or rubber series
pressure-sensitive adhesives, a polyethylene film, a polypropylene
film, etc., is used as the release liner, the releasing strength
becomes 500 g/50 mm width or higher, whereby the problem of
lowering the releasing workability cannot be avoided. In the
present invention, such a problem does not occur. That is, because
the releasing strength of the release liner can be set to 200 g/50
mm width or lower in the sealing material of the present invention,
the release liner can be easily removed from the sealing material
and the sealing material of this invention can be handled as the
case of an ordinary sealing material having a silicone-treated
release liner. As a result thereof, the advantage is obtained that
the change of the apparatus, the working process, etc., accompanied
by the change of the silicone-treated release liner to the
above-described release liner of the present invention, which is
not subjected to a silicone release coating, is unnecessary.
[0093] In the present invention, as a so-called liner-less sealing
material not using such a release liner, a sealing material can be
obtained by forming the layer of the above-described
pressure-sensitive adhesive composition on one side of a sealing
base material and winding in a roll form without applying a
silicone release coating to the back side of the sealing base
material and without inserting a release liner. In particular, the
back side of a sealing base material is constituted with a
polyolefin such as polyethylene, polypropylene, an
ethylene-propylene copolymer, or a mixture thereof, and the sealing
material can be wound in a roll form without inserting a release
liner to obtain a roll-form wound sealing material.
[0094] Though the sealing material does not have a release liner
and the back side of the sealing base material is not subjected to
a silicone release coating, the material has a moderate releasing
property with the back surface of the base material and a releasing
strength adjusted to the same value as the case of using the
aforesaid release liner, and also can maintain the adhesive
strength as the case described above. Accordingly, the sealing
material of this invention can be used as a connecting material for
HDD, etc., which is the same use as the case of using the
above-described release liner not subjected to a silicone release
coating, as a sealing material substantially containing no silicone
compound.
[0095] The 3rd aspect of the present invention provides a
reinforcing sheet comprising an insulating base material and an
adhesive layer which is used for reinforcing the terminal portions
of a tape electric wire.
[0096] Recently, with the propagation of OA equipments and the
development of LAN, multicore cables called "tape electric wires"
(or "flat cables") have been widely used. The tape electric wire of
this kind has a structure that a definite number (not less than 2)
of electrically conductive wires are disposed in an insulating
layer in parallel to each other at an interval.
[0097] In the case of connecting the terminal of the tape electric
wire, the insulating layer is removed at the terminal to expose the
electrically conductive wires, and a reinforcing sheet is adhered
to the exposed portions. As the reinforcing sheet, the sheets
described, for example, in JU-A-61-93936 (the term "JU-A" as used
herein means an "unexamined published Japanese utility model
application"), JP-A-3-283312, JP-4-298980, JP-A-6-260249, and
JP-A-6-260250 are known.
[0098] The reinforcing sheet has a structure that an adhesive
layer, which is to be adhered to the insulating layer (polyester
film) and the electrically conductive wires of the terminal portion
of the tape electric wire, is formed on one surface of the
insulating base material which becomes a reinforcing layer. Also,
the adhesive layer is a structure of stripe coating, double
coating, etc., by selecting an adhesive suitable for each adherend
for strongly adhering to each of the insulating layer and the
electrically conductive wires.
[0099] Furthermore, as the components for the adhesive, a
thermoplastic copolymerized polyester resin, an epoxy
group-containing ethylene copolymer, a vinyl aromatic hydrocarbon
polymer, an acrylic acid ester series polymer, a rubbery material-,
an ethylenic polymer, etc., are recommended. However, in almost all
cases, considering the balance characteristics of the adhesive
property to the insulating layer (polyester film) and the
electrically conductive wires of the tape electric wires, the
adhesive property with the insulating base material (reinforcing
layer), etc., the thermoplastic copolymerized polyester resin has
been widely used.
[0100] However, in conventional reinforcing sheets using the
thermoplastic copolymerized polyester resin as the adhesive layer,
in almost all cases, the adhesive strength at a normal temperature
atmosphere (10 to 50.degree. C.) is insufficient or even when the
adhesive strength at a normal temperature atmosphere is good, the
adhesive strength at a low-temperature atmosphere (lower than
10.degree. C., particularly lower than 0.degree. C.) or at a
high-temperature atmosphere (higher than 50.degree. C. and not
higher than 80.degree. C.) is insufficient.
[0101] The present invention has been made under these
circumstances and the object of the present invention is to provide
a reinforcing sheet comprising an insulating base material and an
adhesive layer for reinforcing the terminal portion of a tape
electric wire, which is excellent in the adhesive property to the
tape electric wires even under a low-temperature atmosphere.
[0102] As the result of various investigations of material
construction of the adhesive layer formed on one surface of an
insulating base material for attaining the above-described object,
the present inventors have found that by using the above-described
specific polyester as the base polymer and properly crosslinking
the base polymer, a reinforcing sheet having a very excellent
adhesive property with tape electric wires under the environment
from normal temperature to a low temperate can be obtained and have
accomplished the present invention.
[0103] That is, the present invention provides a reinforcing sheet
for reinforcing the terminal portion of a tape electric wire having
such a structure that electrically conductive wires are disposed in
an insulating layer at an interval, comprising an insulating base
material having formed on one surface thereof a pressure-sensitive
adhesive layer comprising the above-described specific polyester,
and in particular, the above-described reinforcing sheet wherein
the above-described polyester is further subjected to a
crosslinking treatment and the solvent-insoluble component of the
pressure-sensitive adhesive layer is at least 15% by weight can be
provided.
[0104] In the reinforcing sheet of the present invention, as the
insulating base material, any material may be used as long as the
material effectively functions as a reinforcing layer for the
terminal portion of a tape electric wire and, for example, a
plastic film such as a polyester film, etc., having a thickness of
usually from about 50 to 350 .mu.m or a porous material such as a
paper, a non-woven fabric, etc., is used.
[0105] In the reinforcing sheet of the present invention, the
thickness of the pressure-sensitive adhesive layer formed on one
surface of the above-described insulating base material is usually
from about 10 to 150 .mu.m and as a pressure-sensitive adhesive
composition showing a good adhesive property to the above-described
base material and also to the insulating layer and the conductive
wires constituting the tape electric wire, and in particular,
showing a good adhesive strength under a low-temperature
environment of not higher than about 0.degree. C., the
pressure-sensitive adhesive composition prepared using the
above-described specific polyester as the base polymer is used.
[0106] The components constituting the specific polyester, the
method of crosslinking the polyester, the crosslinking agent, etc.,
are the same as described above, and the used amount of the
above-described polyfunctional compound as the crosslinking agent
is properly selected according to the balance with the polyester to
be crosslinked. In general, it is better to carry out the
crosslinking treatment by combining the crosslinking agent in an
amount of at least about 0.5 part by weight, and preferably from
about 1 to 4 parts by weight per 100 parts by weight of the
polyester, whereby the pressure-sensitive adhesive composition, in
which the solvent-insoluble component is 15% by weight or more, and
preferably 20% by weight or more (usually up to 70% by weight), can
be obtained. If the solvent-insoluble component of the
pressure-sensitive adhesive component is less than 15% by weight,
the cohesive force is insufficient and a sufficient adhesive
property can not be obtained.
[0107] The used amount of the above-described polyfunctional
compound is properly selected according to the balance with the
polyester to be crosslinked. In general, it is better to carry out
the crosslinking treatment by compounding the polyfunctional
compound in an amount of at least about 0.5 part by weight, and
preferably from about 1 to 4 parts by weight per 100 parts by
weight of the polyester, whereby the pressure-sensitive adhesive
composition wherein the solvent-insoluble component is 15% by
weight or more, and preferably 20% by weight or more (usually up to
70% by weight) can be obtained. If the solvent-insoluble component
of the pressure-sensitive adhesive composition is less than 15% by
weight, the cohesive force is insufficient and a sufficient
adhesive property can not be obtained.
[0108] As other crosslinking means, there is a method of
compounding the above-described polyfunctional monomer as a
crosslinking agent with the polyester and crosslinking the
polyester by electron rays, etc. It is better that the used amount
of the polyfunctional monomer is at least about 1 part by weight,
and preferably from about 2 to 4 parts by weight per 100 parts by
weight of the polyester such that the solvent-insoluble component
of the pressure-sensitive adhesive composition after crosslinked by
electron rays falls within the above-described values.
[0109] In the reinforcing sheet of the present invention, the
thickness of the pressure-sensitive adhesive layer formed on one
surface of the above-described insulating base material is usually
from about 10 to 150 .mu.m, and as the pressure-sensitive adhesive
composition showing a good adhesive property to the above-described
base material and the insulating layer and the conductive wires
constituting the tape electric wire and, in particular, showing a
good adhesive property in the atmosphere from a low temperature
atmosphere of lower than 10.degree. C. to a normal temperature
atmosphere of from 10 to 50.degree. C. and in a high-temperature
atmosphere of from higher than 50 to 80.degree. C., the following
specific pressure-sensitive adhesive composition is used.
[0110] The specific pressure-sensitive adhesive composition is
preferably the composition comprising, along with the
above-described polymer having the polycarbonate structure, a resin
having a softening point of at least 80.degree. C. in a ratio of
from 10 to 50% by weight of the sum total of the polymer and the
resin. The content of the resin is from 10 to 50% by weight,
preferably from 13 to 45% by weight, and more preferably from 15 to
35% by weight. If the content of the resin is more than 50% by
weight, the shock resistance at a low temperature is lowered and if
the content is less than 10% by weight, the shear adhesive strength
is lowered, and in both cases, it becomes difficult to show a good
adhesive strength in a wide temperature range of from a low
temperature to a high temperature.
[0111] It is better that the pressure-sensitive adhesive
composition used in this case contains the polymer having the
polycarbonate structure and the specific resin in the
above-described ratios and the content of the solvent-insoluble
component is set in the range of preferably from 10 to 90% by
weight, more preferably from 15 to 85% by weight, and still more
preferably from 20 to 80% by weight. If the content of the solvent
insoluble component is too low, the durability is inferior and if
the content is too high, the adhesive property is inferior. Thus,
both cases are not preferred.
[0112] The pressure-sensitive adhesive composition may further
contain additives usually used, for example, a crosslinking agent
such as an epoxy compound, an isocyanate compound, etc.; a filler
such as glass fibers, a metal powder, etc., a pigment, a coloring
agent, and a plasticizer.
[0113] Reinforcing the terminal portion of a tape electric wire by
the use of the reinforcing sheet of the present invention thus
constituted can be carried out according to an ordinary method. For
example, after removing an insulating layer at the terminal portion
of a tape electric wire having a structure such that 2 or more
electrically conductive wires are disposed in an insulating layer
at an interval to thereby expose the conductive wires, the
above-described reinforcing sheet of the present invention is
adhered to the exposed portion by utilizing adhesive strength of
the pressure-sensitive adhesive layer to reinforce the foregoing
terminal portion.
[0114] The 4th aspect of the present invention is a
pressure-sensitive adhesive sheet for printing.
[0115] That is, because a silicone thin film which prevents
attaching of a viscous material is not formed on the back surface
of the base material of the above-described pressure-sensitive
adhesive sheet, by using an ink ribbon coated with an ink
containing a plastic component (e.g., the resin same as or similar
to the base material) having an adhesive property to the base
material and a coloring agent (e.g. organic or inorganic, dyes or
pigments), heat-transferring the ink of the ink ribbon onto the
back surface of the base material by a heat-transfer printer
generally known, the ink is adhered to the back surface by a
physical means such as welding, melt-attaching, etc., whereby
printing can be applied.
[0116] Accordingly, in such a printing use, the base material is
preferably porous in the point of the close attaching property, and
also when the base material has a hiding property, the print can be
clearly recognized in the relation with contrast.
[0117] There is no particular restriction on the means of making
porous and, for example, the porous base material can be obtained
by imparting strain to the base material and also forming fine
cracks by a stretching operation. Such a stretching operation
simultaneously imparts a light scattering function to the base
material, and the hiding property is therefore improved.
[0118] The hiding property can be also obtained by compounding a
filler, etc., but the porous base material may be composed of
plural layers such that the back side is constituted with a
polyolefin layer and a layer between the polyolefin layer and a
pressure-sensitive adhesive layer is constituted with an opaque
material (e.g., a paper) as a support layer.
BEST MODES FOR CARRYING OUT THE INVENTION
[0119] The present invention is described more practically by the
following examples below, wherein all parts are by weight. Also,
the weight average molecular weight of each polymer is a
polystyrene converted value by a gel permeation chromatography.
EXAMPLE 1-1
[0120] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.512 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115 KOH mg/g), 51.8 g (acid group: 0.512 equivalent) of
sebacic acid, and 127 mg of dibutyltin oxide (DBTO) as a catalyst,
the temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 24 hours, a polyester having a weight average
molecular weight of 55,000 was obtained. After diluting the
polyester with toluene to a solid component concentration of 40% by
weight, 2 parts (solid components) of the hexamethylene
diisocyanate addition product of trimethylolpropane (Coronate HL,
trade name, made by Nippon Polyurethane Industry Co., Ltd.) per 100
parts (solid component) of the polyester was added thereto as a
crosslinking agent to provide a pressure-sensitive adhesive
composition. The composition was coated on a polyethylene
terephthalate film (hereinafter referred to as PET film) of 38
.mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness, and further the layer was subjected
to aging in an atmosphere of 50.degree. C. for 5 days as post cure
to prepare a pressure-sensitive adhesive tape.
[0121] Also, by the same procedure as above, the pressure-sensitive
adhesive layer of 50 .mu.m in thickness was formed on a releasing
paper for -measuring the storage modulus of elasticity.
EXAMPLE 1-2
[0122] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 23.5 g (acid group: 0.25 equivalent) of
azelaic acid, and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 25 hours, a polyester having a weight average
molecular weight of 78,000 was obtained.
[0123] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 1.5 parts (solid
components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness, and
further the layer was subjected to aging in an atmosphere of
50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape.
[0124] Also, by the same procedure as above, the pressure-sensitive
adhesive layer of 50 .mu.m in thickness was formed on a releasing
paper for measuring the storage modulus of elasticity.
EXAMPLE 1-3
[0125] By following the same procedure as Example 1-2 except that
2.5 parts (solid components) of the hexamethylene diisocyanate
addition product of trimethylolpropane (Coronate HL, made by Nippon
Polyurethane Industry Co., Ltd.) was added as the crosslinking
agent in place of Coronate L, a pressure-sensitive adhesive tape
was prepared. Also, by the same procedure as above, the
pressure-sensitive adhesive layer of 50 .mu.m in thickness was
formed on a releasing paper for measuring the storage modulus of
elasticity.
EXAMPLE 1-4
[0126] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 12.6 g of sebacic acid and 11.8 g (total acid
groups: 0.25 equivalent) of azelaic acid, and 62 mg of DBTO as a
catalyst, the temperature of the mixture was raised to 180.degree.
C. while stirring in the presence of a small amount of toluene as a
reaction water discharging solvent, and the mixture was maintained
at the temperature. After a while, the outflow and separation of
water were observed and the reaction began to proceed. By
continuing the reaction for about 25 hours, a polyester having a
weight average molecular weight of 75,000 was obtained.
[0127] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 2 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness, and
further the layer was subjected to aging in an atmosphere of
50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape. Also, by the same procedure as
above, the pressure-sensitive adhesive layer of 50 .mu.m in
thickness was formed on a releasing paper for measuring the storage
modulus of elasticity.
COMPARATIVE EXAMPLE 1-1
[0128] In a reaction vessel equipped with a stirrer and a
thermometer were placed 95 parts of n-butyl acrylate, 5 parts of
acrylic acid, 150 parts of toluene, and 0.1 part of
azobis-isobutyronitrile and then a solution polymerization was
carried out at 60.degree. C. for about 7 hours in a nitrogen gas
atmosphere to provide a polymer solution. By adding 2 parts (solid
components) of the tolylenene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid components)
of the polymer was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness by an applicator, followed by drying at 130.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness and further the layer was subjected to aging in
an atmosphere of 50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape. Also, by the same procedure as
above, the pressure-sensitive adhesive layer of 50 .mu.m in
thickness was formed on a releasing paper for measuring the storage
modulus of elasticity.
COMPARATIVE EXAMPLE 1-2
[0129] In a reaction vessel equipped with a stirrer and a
thermometer were placed 80 parts of 2-ethylhexyl acrylate, 20 parts
of acrylic acid, and 0.6 part of Irgacure 184 (trade name, made by
Ciba-Geigy Corporation) as a photopolymerization initiator and
after sufficiently replacing the inside atmosphere with a nitrogen
gas, the mixture was irradiated with ultraviolet rays by a
high-pressure mercury lamp at a dosage of about 100 mj/cm.sup.2.
The viscous material obtained by the irradiation was compounded
with 1 part of trimethylolpropane triacrylate to provide a
pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness to provide a thickness of 50 .mu.m.
[0130] Thereafter, to remove the polymerization hindrance with
oxygen, the coated layer was covered by a PET releasing liner and
irradiated with ultraviolet rays by a high-pressure mercury lamp at
a dosage of about 1,400 mj/cm.sup.2 to form a pressure-sensitive
layer, whereby a pressure-sensitive adhesive tape was prepared.
Also, by the same procedure as above, the pressure-sensitive
adhesive layer of 50 .mu.m in thickness was formed on a releasing
paper for measuring the storage modulus of elasticity.
[0131] About each of the pressure-sensitive adhesive tapes obtained
in Examples 1-1 to 1-4 and Comparative Examples 1-1 and 1-2, the
storage elastic moduluses at -30.degree. C., room temperature
(23.degree. C.), and 80.degree. C. and the adhesive strength
(180.degree. release adhesion) at room temperate (23.degree. C.)
were determined by the following methods.
[0132] The obtained results are shown in Table 1-1 below.
[0133] Storage Elastic Modulus
[0134] The storage elastic modulus [G'] means a shear storage
elastic modulus of a pressure-sensitive adhesive composition and
said to be an elastic component storing an energy added from
outside as a stain energy but the measurement of the storage
elastic modulus [G'] was carried out by a system of measuring using
a dynamic viscoelasticity measurement apparatus RDS-11 manufactured
by Rheometrics, Inc. by a jig of parallel plate of a sample
thickness of about 1.5 mm and a diameter of 7.9 mm at a frequency
of 1 Hz.
[0135] Adhesive strength
[0136] The pressure-sensitive adhesive tape was stuck to an acryl
plate (polymethyl methacrylate) as an adherend and 180.degree. peel
adhesive strength was measured under the condition of an
atmospheric temperature of 23.degree. C., a stuck time of 30
minutes, and a releasing rate of 300 mm/minute.
1 TABLE 1 Adhesive Storage Elastic Modulus [G'] Strength
(dyne/cm.sup.2) (kg/20 -30.degree. C. 23.degree. C. 80.degree. C.
mm width) Ex 1-1 1.5 .times. 10.sup.7 7.1 .times. 10.sup.6 3.7
.times. 10.sup.6 1.6 Ex 1-2 1.6 .times. 10.sup.7 9.6 .times.
10.sup.6 5.1 .times. 10.sup.6 2.1 Ex 1-3 1.8 .times. 10.sup.7 1.5
.times. 10.sup.7 1.1 .times. 10.sup.7 1.8 Ex 1-4 1.8 .times.
10.sup.7 1.2 .times. 10.sup.7 9.1 .times. 10.sup.6 2.0 CE 1-1 5.2
.times. 10.sup.7 1.1 .times. 10.sup.6 3.4 .times. 10.sup.5 1.3 CE
1-2 1.9 .times. 10.sup.9 2.6 .times. 10.sup.7 7.9 .times. 10.sup.5
0.4 Ex: Example CE: Comparative Example
[0137] Then, about each of the pressure-sensitive adhesive tapes
obtained in Examples 1-1 to 1-4 and Comparative Examples 1-1 and
1-2, the thumb tack at room temperature (23.degree. C.) and the
heat resistance (80.degree. C.) were measured by the following
methods. These results are shown in Table 1-2 below.
[0138] Thumb Tack
[0139] The surface of each pressure-sensitive adhesive tape was
touched with the thumb at room temperature (23.degree. C.), after
pressing the thumb to the surface for a short time (about 1
second), the thumb was separated from the surface, and the thumb
tack was evaluated by the resistance that the surface of the thumb
felt.
[0140] Measurement of Heat Resistance
[0141] Each pressure-sensitive adhesive tape was stuck to a
bakelite plate as an adherend, a load of 500 g/2 cm.sup.2 was
applied to the perpendicular direction at an atmospheric
temperature of 80.degree. C., and the retention time (minute) until
the tape falls was measured.
2 TABLE 1-2 Heat Resistance (retention time: Thumb Tack minute)
Example 1-1 none >120 Example 1-2 none >120 Example 1-3 none
>120 Example 1-4 none >120 C. Example 1-1 felt >120 C.
Example 1-2 none >120 C. Example: Comparative Example
[0142] From the results shown in Table 1-1 and Table 1-2 above, it
can seen that each of the pressure-sensitive adhesive tapes in
Examples 1-1 to 1-4 of the present invention has not only high
elasticity and tack free but also a large adhesive strength as
compared with the pressure-sensitive adhesive tapes in Comparative
Examples 1-1 and 1-2, and also is satisfactory in the heat
resistance.
EXAMPLE 2-1
[0143] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 200 g (hydroxy
group: 0.41 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 20.51 g (acid group: 0.41 equivalent) of
succinic anhydride, and 102 mg of DBTO as a catalyst, the
temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 27 hours, a polyester having a weight average
molecular weight of 56,000 was obtained.
[0144] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness, and
further the layer was subjected to aging in an atmosphere of
50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 2-2
[0145] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.512 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 37.44 g (acid group: 0.512 equivalent) of
adipic acid, and 127 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 58,000 was obtained.
[0146] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness, and
further the layer was subjected to aging in an atmosphere of
50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 2-3
[0147] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 25.28 g (acid group: 0.25 equivalent) of
sebacic acid, and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 25 hours, a polyester having a weight average
molecular weight of 72,000 was obtained.
[0148] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 2 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness, and
further the layer was subjected to aging in an atmosphere of
50.degree. C. for 5 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 2-4
[0149] After diluting the polyester obtained in Example 2-3 with
toluene to a solid component concentration of 50% by weight, 3
parts (solid components) of trimethylolpropane triacrylate was
added thereto per 100 parts (solid component) of the polyester as a
crosslinking agent to provide a pressure-sensitive adhesive
composition. The composition was coated on a PET film of 38 .mu.m
in thickness by an applicator, followed by drying at 100.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness and further, the layer was irradiated by
electron rays at 6 Mrad to prepare a pressure-sensitive adhesive
tape.
[0150] With respect to each of the pressure-sensitive adhesive
tapes obtained in Examples 2-1 to 2-4 described above, the
solvent-insoluble component of the polyester, the adhesive
strength, and the heat resistance were measured. These results are
shown in Table 2-1 below. In addition, the solvent-insoluble
component and the adhesive strength were measured by the methods
described below and the heat resistance was measured by the method
described above.
[0151] Measurement of Solvent-Insoluble Component
[0152] About 0.1 g of the pressure-sensitive adhesive was sampled
from the pressure-sensitive adhesive tape and accurately weighed.
After immersing the sample in about 50 ml of toluene for 5 days at
room temperature, solvent-insoluble component was taken out, after
drying at 130.degree. C. for about one hour, the component was
weighed. The solvent-insoluble component [X] (weight %) was
calculated by the following equation.
X(%)=(A (g)/B (g)).times.100
[0153] A: The weight after immersion and drying
[0154] B: The weight of the sample
[0155] Measurement of Adhesive strength
[0156] The pressure-sensitive adhesive tape was stuck to a
polycarbonate plate or an acryl plate (polymethyl acrylate) as an
adherend and then the 180.degree. C. peel adhesive strength was
measured under the conditions of an atmospheric temperature of
23.degree. C., a stuck time of 30 minutes and a releasing rate of
300 mm/minute.
3 TABLE 2-1 Solvent- Adhesive strength Insoluble (kg/20 mm width)
Retention Component Polycarbonate Acryl Time (weight %) Plate Plate
(minute) Ex 2-1 25 2.8 2.3 .gtoreq.120 Ex 2-2 33 3.0 2.5
.gtoreq.120 Ex 2-3 65 2.8 1.9 .gtoreq.120 Ex 2-4 41 2.2 1.8
.gtoreq.120 Ex: Example
[0157] As is clear from the results shown in the above Table 2-1,
it can be seen that each of the pressure-sensitive adhesive tapes
having the pressure-sensitive adhesive compositions, respectively,
in Examples 2-1 to 2-4 of the present invention has a good adhesive
strength and is greatly excellent in the heat resistance.
EXAMPLE 3-1
[0158] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 200.0 g (hydroxy
group: 0.41 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 20.51 g (acid group: 0.410 equivalent) of
succinic anhydride, and 102 mg of DBTO as a catalyst, the
temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 65,000 was obtained.
[0159] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 2 parts (solid
components) of diphenylmethane diisocyanate (Millionate MT, trade
name, made by Nippon Polyurethane Industry Co., Ltd.) per 100 parts
(solid components) of the polyester was added thereto as a
crosslinking agent to provide a solution of a pressure-sensitive
adhesive composition. The solution was coated on a PET film of 38
.mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness. Then, the layer was further
subjected to aging in an atmosphere of 50.degree. C. for 2 days as
post cure to prepare a pressure-sensitive adhesive tape.
EXAMPLE 3-2
[0160] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.512 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 37.44 g (acid group: 0.512 equivalent) of
adipic acid, and 127 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 35 hours, a polyester having a weight average
molecular weight of 80,000 was obtained.
[0161] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 1 part (solid components)
of diphenylmethane diisocyanate and 0.5 part (solid components) of
the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid components)
of the polyester were added thereto as crosslinking agents to
provide a solution of a pressure-sensitive adhesive composition.
The solution was coated on a PET film of 38 .mu.m in thickness by
an applicator, followed by drying at 130.degree. C. for 5 minutes,
to form a pressure-sensitive adhesive layer of 50 .mu.m in
thickness. Then, the layer was further subjected to aging in an
atmosphere of 50.degree. C. for 2 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 3-3
[0162] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.250 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 25.28 g (acid group: 0.250 equivalent) of
sebacic acid, and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of xylene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 90,000 was obtained.
[0163] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 0.8 part (solid
components) of diphenylmethane diisocyanate and 0.2 part (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid components)
of the polyester were added thereto as crosslinking agents to
provide a solution of a pressure-sensitive adhesive composition.
The solution was coated on a PET film of 38 .mu.m in thickness by
an applicator, followed by drying at 130.degree. C. for 5 minutes,
to form a pressure-sensitive adhesive layer of 50 .mu.m in
thickness. Then, the layer was further subjected to aging in an
atmosphere of 50.degree. C. for 2 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 3-4
[0164] To 100 parts (solid components) of the polyester obtained in
Example 3-3 was added 3 parts of 1,6-hexanediol diacrylate as a
substantial crosslinking agent to provide a solution of a
pressure-sensitive adhesive composition. The solution was coated on
a PET film of 38 .mu.m in thickness by an applicator, followed by
drying at 100.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness. The
layer was further irradiated by electron rays at 3 Mrad to prepare
a pressure-sensitive adhesive tape.
REFERENCE EXAMPLE 3-1
[0165] To 100 parts (solid components) of the polyester obtained in
Example 3-3 was added 2 parts (solid components) of the
hexamethylene diisocyanate addition product of trimethylolpropane
(Coronate HL, trade name, made by Nippon Polyurethane Industry Co.,
Ltd.) as a substantial crosslinking agent to provide a solution of
a pressure-sensitive adhesive composition. The solution of the
pressure-sensitive adhesive composition was coated on a PET film of
38 .mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness. Furthermore, the layer was
subjected to aging in an atmosphere of 50.degree. C. for 2 days to
prepare a pressure-sensitive adhesive tape.
COMPARATIVE EXAMPLE 3-1
[0166] The polyester solution obtained in Example 3-3 was coated on
a PET film of 38 .mu.m in thickness by an applicator, followed by
drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, the layer was subjected to aging in an atmosphere of
50.degree. C. for 2 days to prepare a pressure-sensitive adhesive
tape.
COMPARATIVE EXAMPLE 3-2
[0167] In 150 parts of toluene were dissolved 100 parts of a
styrene-isoprene-styrene block polymer (Cariflex TR1107, trade
name, made by Shell Chemical Co.), 50 parts of a petroleum resin,
and 1 part of a phenol series antioxidant to provide a solution of
a pressure-sensitive adhesive composition. The solution was coated
on a PET film of 38 .mu.m in thickness by an applicator, followed
by drying at 100.degree. C. for 3 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, the layer was subjected to aging in an atmosphere of
50.degree. C. for 2 days to prepare a pressure-sensitive adhesive
tape.
[0168] With respect to each of the pressure-sensitive adhesive
tapes obtained in Examples 3-1 to 3-4, Reference Example 3-1, and
Comparative Example 3-1 and 3-2, the solvent-insoluble components,
the self-adhesive strength, the heat resistance, and weather
resistance were measured. The results are as shown in Table 3-1
below.
[0169] In addition, the solvent-insoluble component was measured by
the method described above and the self-adhesive strength, the heat
resistance, and the weather resistance were measured by the
following methods.
[0170] Measurement of Self-adhesive strength
[0171] Two pressure-sensitive adhesive tapes each having a width of
20 mm and a length of 150 mm were stuck to each other at the
pressure-sensitive adhesive surfaces of the central portions
thereof using a roller of 2 kg, and the releasing strength was
measured under the conditions of an atmospheric temperature of
23.degree. C., 20 minutes after sticking, and a releasing rate of
300 mm/minute.
[0172] Measurement of Heat Resistance
[0173] The pressure-sensitive adhesive tape was stuck to a
stainless steel plate (SUS 304), after allowing to stand for 7 days
at an atmospheric temperature of 80.degree. C., the tape was
released by the hand, and the presence or absence of stain was
confirmed. The criteria for the evaluation were as follows.
[0174] A: No adhesive remained.
[0175] B: Adhesive partially remained (area ratio: less than
5%).
[0176] C: Adhesive remained (area ratio: not less than 5%).
[0177] Measurement of Weather Resistance
[0178] The pressure-sensitive adhesive tape was stuck to a
stainless steel plate (SUS 304) as an adherend, after exposed in
the open air (directing the south, 30.degree. C.) for 30 days, the
plate was released by the hand, and the presence or absence of
stain was confirmed. The criteria for the evaluation were as
follows.
[0179] A: No adhesive remained.
[0180] B: Adhesive partially remained (area ratio: less than
5%).
[0181] C: Adhesive remained (area ratio: not less than 5%).
4 TABLE 3-1 Self- Solvent- Adhesive Insoluble Strength Component
(kg/20 mm Heat Weather (weight %) width) Resistance Resistance Ex
3-l 10 5.5 A A Ex 3-2 12 5.2 A A Ex 3-3 8 4.8 A A Ex 3-4 5 4.2 A A
RE 3-1 40 1.5 A A CE 3-1 0 1.9 C C CE 3-2 0 1.6 C C Ex: Example,
RE: Reference Example, CE: Comparative Example
[0182] As is apparent from the above Table 3-1, it can be seen that
each of the pressure-sensitive adhesive tapes in Examples 3-1 to
3-4 having the pressure-sensitive adhesive compositions of the
present invention, while being tack free at room temperature, shows
a good self-adhesive strength and also shows the good durability
such as the excellent heat resistance and weather resistance. On
the other hand, the pressure-sensitive adhesive tapes in. Reference
Example 3-1 and Comparative Examples 3-1 and 3-2 are inferior in
the self-adhesive strength or are inferior in the durability such
as the heat resistance and the weather resistance.
EXAMPLE 4-1
[0183] In a reaction vessel equipped with a condenser, a nitrogen
introducing tube, a thermometer, and a stirrer were placed 50 parts
of ethyl acetate and 50 parts of toluene as solvents, 80 parts of
2-ethylhexyl acrylate, 12 parts of n-butyl acrylate, 8 parts of
acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and 0.1 part of
2,2'-azobisisobutyro-nitrile, the polymerization was carried out in
a nitrogen gas stream to provide a solution of an acrylic polymer A
having a glass transition temperature of -43.degree. C. and a
weight average molecular weight of 600,000.
[0184] Apart from this, in a reaction vessel equipped with a
thermometer, a stirrer, and a water separator were placed 100 parts
of polycarbonate diol (PLACCEL CD220PL, trade name, made by DAICEL
CHEMICAL INDUSTRIES, LTD., hydroxy group value 56.1 KOH mg/g), 10.1
parts of sebacic acid, and 0.025 part of DBTO as a catalyst and the
temperature of the mixture was raised to 180.degree. C. with
stirring in the presence of toluene as a reaction water discharging
solvent. After a while, the outflow and the separation of water
were observed. By carrying out the reaction for about 24 hours, a
solution of a polyester series polymer B having a weight average
molecular weight of 60,000 was obtained.
[0185] The solution of the acrylic polymer A described above was
mixed with the solution of the polyester series polymer B described
above such that the polyester series polymer B became 20 parts per
80 parts of the acrylic polymer A and further 2 parts of the
tolylene diisocyanate addition product of trimethylolpropane was
further added to the mixture, followed by mixing, to provide a
solution of a pressure-sensitive adhesive composition. Then, the
solution of the pressure-sensitive adhesive composition was coated
on one surface of a polyester film of 38 .mu.m in thickness at a
dry thickness of 50 .mu.m, followed by drying at 120.degree. C. for
2 minutes, to prepare a pressure-sensitive adhesive tape.
[0186] Also, the solution was coated on one surface of a polyester
film subjected to a release coating in the same manner as above to
prepare a sample for measuring the solvent-insoluble component.
EXAMPLE 4-2
[0187] The solution of the acrylic polymer A and the solution of
the polyester series polymer B obtained in Example 4-1 were mixed
with each other such that the polyester series polymer B became 50
parts per 50 parts of the acrylic polymer A, and 2 parts of the
tolylene diisocyanate addition product of trimethylolpropane was
added to the mixture, followed by mixing, to provide a solution of
a pressure-sensitive adhesive composition. Using the solution, a
pressure-sensitive adhesive tape was prepared in the same manner as
in Example 4-1. Also, in the same manner as in Example 4-1, a
sample for measuring the solvent-insoluble component was
prepared.
EXAMPLE 4-3
[0188] The solution of the acrylic polymer A and the solution of
the polyester series polymer B obtained in Example 4-1 were mixed
with each other such that the polyester series polymer B became 80
parts per 20 parts of the acrylic polymer A, and 2 parts of the
tolylene diisocyanate addition product of trimethylolpropane was
added to the mixture, followed by mixing, to provide a solution of
a pressure-sensitive adhesive composition. Using the solution, a
pressure-sensitive adhesive tape was prepared in the same manner as
in Example 4-1. Also, a sample for measuring the solvent-insoluble
component was prepared in the same manner as in Example 4-1.
EXAMPLE 4-4
[0189] The solution of the polyester series polymer B obtained in
Example 4-1 was coated on a separator and dried at 80.degree. C.
for one hour to provide the solid component of the polyester series
polymer B. Then, 40 parts of the solid component was dissolved in a
monomer mixture (the glass transition temperature of the copolymer
of the mixture was -40.degree. C.) composed of 48 parts of
2-ethylhexyl acrylate, 12 parts of acryloylmorpholine, and 0.06
part of 2-hydroxyethyl acrylate, and further 0.1 part of
2,2-dimethoxy-2-phenyl-acetophenone and 2 parts of the tolylene
diisocyanate addition product of trimethylolpropane were added to
the solution, followed by mixing.
[0190] The mixed solution was coated on one surface of a polyester
film of 38 .mu.m in thickness such that the thickness after the
irradiation of ultraviolet rays was 50 .mu.m and thereafter the
coated layer was irradiated by ultraviolet rays to polymerize the
above-described monomer mixture and cure, thereby a
pressure-sensitive adhesive tape was prepared.
[0191] Also, the mixed solution was coated on one surface of a
polyester film subjected to a releasing treatment in the same
manner as above and then irradiated with ultraviolet rays to
prepare a sample for measuring the solvent-insoluble component.
REFERENCE EXAMPLE 4-1
[0192] To the solution of the polyester series polymer B obtained
in Example 4-1 was added 2 parts of the tolylene diisocyanate
addition product of trimethylolpropane per 100 parts of the
polyester series polymer B, followed by mixing, to provide a
solution of a pressure-sensitive adhesive composition. Using the
solution, a pressure-sensitive adhesive tape was prepared in the
same manner as in Example 4-1. Also, a sample for measuring
solvent-insoluble components was prepared in the same manner as in
Example 4-1.
COMPARATIVE EXAMPLE 4-1
[0193] To the solution of the acrylic polymer A obtained in Example
4-1 was added 2 parts of the tolylene diisocyanate addition product
of trimethylolpropane per 100 parts of the acrylic polymer A,
followed by mixing, to provide a solution of a pressure-sensitive
adhesive composition. Using the solution, a pressure-sensitive
adhesive tape was prepared in the same manner as in Example 4-1.
Also, a sample for measuring solvent-insoluble components was
prepared in the same manner as in Example 4-1.
COMPARATIVE EXAMPLE 4-2
[0194] To the solution of the acrylic polymer A obtained in Example
4-1 were added 20 parts of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD., hydroxy group
value 56.1 KOH mg/g) and 2 parts of the tolylene diisocyanate
addition product of trimthylolpropane, followed by mixing, to
provide a solution of a pressure-sensitive adhesive composition.
Using the solution of the pressure-sensitive adhesive composition,
a pressure-sensitive adhesive tape was prepared in the same manner
as in Example 4-1. Also, a sample for measuring the
solvent-insoluble component was prepared in the same manner as in
Example 4-1.
[0195] With respect to the pressure-sensitive adhesive tapes
prepared in Examples 4-1 to 4-4, Reference Example 4-1, and
Comparative Examples 4 -1 and 4-2, the adhesive strength and the
holding power were measured by the methods described below. The
obtained results are shown in Table 4-1 below, along with the
solvent-insoluble components of the pressure-sensitive adhesive
compositions, which were measured by the method described
above.
[0196] In the same table, "X.sub.1" in the column of the
solvent-insoluble component indicates the results obtained by the
use of toluene as the solvent and "X.sub.2" indicates the results
obtained by the use of ethyl acetate as the solvent. In the case of
using ethyl acetate, after the sample was immersed in the solvent
for 3 days at room temperature, the sample was dried at 100.degree.
C. for 2 hours, weighed, and calculated.
[0197] Adhesive strength
[0198] The pressure-sensitive adhesive tape of 20 mm.times.100 mm
was press-stuck to an adherend by a method of reciprocating once a
roller of 2 kg, after allowing to stand for 20 minutes at
23.degree. C. and 48 hours at 70.degree. C., the 180 degree peel
adhesive strength was measured in an atmosphere of 23.degree. C.
and 65% RH at a pulling rate of 300 mm/minute. As the adherend, a
polycarbonate plate, an acrylic resin plate and a stainless steel
(SUS 430BA) plate were used. In the table, "A" is a polycarbonate
plate, "B" is an acrylic resin plate, and "C" is a stainless steel
plate.
[0199] Holding power
[0200] The pressure-sensitive adhesive tape having a width of 10 mm
was stuck to a phenol resin plate with the adhered area of 10
mm.times.20 mm, and after 20 minutes since then, was allowed to
stand at 80.degree. C. for 20 minutes. Then, the phenol resin plate
was hung down, a uniform load of 500 g was applied to a free end of
the pressure-sensitive adhesive tape, and the falling time (minute)
of the pressure-sensitive adhesive tape at 80.degree. C. and the
slipped distance (mm) thereof after 120 minutes were measured.
5 TABLE 4-1 Solvent Insoluble Holding Component Adhesive Strength
Power (weight %) (g/20 mm width) Time (S)* X.sub.1 X.sub.2 A B C
(min) (mm) E 4-1 56 57 1,520 1,450 1,180 >120 1 E 4-2 55 55
1,800 1,560 1,100 >120 1 E 4-3 53 52 1,920 1,720 1,060 >120 1
E 4-4 64 65 1,820 1,650 1,250 >120 .ltoreq.0.5 R 4-1 54 55 2,260
1,900 620 >120 1.5 C 4-1 60 60 1,150 1,280 1,160 >120
.ltoreq.0.5 C 4-2 25 25 1,200 1,320 1,250 5 -- (S)*: Slipped
distance E: Example R: Reference Example C: Comparative Example
[0201] From the above Table 4-1, it is clear that the
pressure-sensitive adhesive tapes of Examples 4-1 to 4-4 have a
large adhesive strength to various adherends, in particular to
plastics such as polycarbonate, an acrylic resin, etc., and also
have a large holding power and are excellent in the durability.
EXAMPLE 5-1
[0202] In a reaction vessel equipped with a thermometer, a stirrer,
and a water separator were placed 100 parts of polycarbonate diol
(PLACCEL CD220PL, trade name, made by DAICEL CHEMICAL INDUSTRIES,
LTD., hydroxy group value 56.1 KOH mg/g), 10.1 parts of sebacic
acid, and 0.025 part of DBTO and the temperature of the mixture was
raised to 180.degree. C. with stirring in the presence of toluene
as a reaction water discharging solvent. After a while, the outflow
and the separation of water were observed. By continuing the
reaction for about 24 hours, a solution of a polyester series
polymer having a weight average molecular weight of 60,000 was
obtained.
[0203] To the solution of the polyester series polymer were added
30 parts of a terpenephenol resin having a softening point of
115.degree. C. and 2 parts of the hexamethylene diisocyanate
addition product of trimethylolpropane per 100 parts of the solid
components thereof, followed by mixing, to provide a solution of a
heat pressure-sensitive adhesive composition. Then, the solution of
the heat pressure-sensitive adhesive composition was coated on one
surface of a polyester film of 38 .mu.m in thickness at a dry
thickness of 50 .mu.m, followed by drying at 120.degree. C. for 2
minutes, to prepare a pressure-sensitive adhesive tape for
measuring the holding power.
[0204] Also, the solution was coated on one surface of a polyester
film subjected to a release coating by the same manner as above to
prepare a pressure-sensitive adhesive tape for measuring the shear
adhesive strength and the shock resistance.
EXAMPLE 5-2
[0205] By following the same procedure as in Example 5-1 except
that 20 parts of a rosinphenol resin having a softening temperature
of 145.degree. C. was used in place of 30 parts of the
terpenephenol resin having a softening point of 115.degree. C., a
solution of a heat pressure-sensitive adhesive composition was
prepared. Using the solution, the pressure-sensitive adhesive tapes
for measuring the holding power and for measuring the shear
adhesive strength and the shock resistance were prepared.
EXAMPLE 5-3
[0206] By following the same procedure as Example 5-1 except that
50 parts of a coumarone-indene resin having a softening point of
120.degree. C. was used in place of 30 parts of the terpenephenol
resin having a softening point of 115.degree. C., a solution of a
heat pressure-sensitive adhesive composition was prepared and using
the solution, pressure-sensitive adhesive tapes for measuring the
holding power and for measuring the shear adhesive strength and the
shock resistance were prepared.
REFERENCE EXAMPLE 5-1
[0207] To the solution of the polyester series polymer obtained in
Example 5-1 was added 2 parts of the tolylene diisocyante addition
product of trimethylolpropane per 100 parts of the solid components
thereof, followed by mixing, to provide a solution of a heat
pressure-sensitive adhesive composition. Then, using the solution
of the heat pressure-sensitive adhesive composition,
pressure-sensitive adhesive tapes for measuring the holding power
and for measuring the shear adhesive strength and the shock
resistance were prepared in the same manners as in Example 5-1.
REFERENCE EXAMPLE 5-2
[0208] By following the same procedure as in Example 5-1 except
that 30 parts of a terpenephenol resin having a softening point of
50.degree. C. was used in place of 30 parts of the terpenephenol
resin having a softening point of 115.degree. C., a solution of a
heat pressure-sensitive adhesive composition was prepared. Using
the solution, pressure-sensitive adhesive tapes for measuring the
holding power and for measuring the shear adhesive strength and the
shock resistance were prepared.
COMPARATIVE EXAMPLE 5-1
[0209] In a reaction vessel equipped with a condenser, a nitrogen
introducing tube, a thermometer, and a stirrer were placed 50 parts
of ethyl acetate and 50 parts of toluene as solvents, 50 parts of
2-ethylhexyl acrylate, 45 parts of n-butyl acrylate, 4.9 parts of
acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and 0.1 part of
2,2'-azobis-isobutyronitrile, the polymerization was carried out in
a nitrogen gas stream to provide a solution of an acrylic polymer
having a weight average molecular weight of 700,000.
[0210] To the solution of the polyester series polymer were added
30 parts of a terpenephenol resin having a softening point of
115.degree. C. and 2 parts of the hexamethylene diisocyanate
addition product of trimethylolpropane per 100 parts of the solid
components thereof, followed by mixing, to provide a solution of a
heat pressure-sensitive adhesive composition. Then, using the
solution of the heat pressure-sensitive adhesive composition,
pressure-sensitive adhesive tapes for measuring the holding power
and for measuring the shear adhesive strength and the shock
resistance were prepared.
[0211] With respect to each of the pressure-sensitive adhesive
tapes prepared in Examples 5-1 to 5-3, Reference Examples 5-1 and
5-2, and Comparison Example 5-1, the holding power, the shear
adhesive strength, and the shock resistance were measured by the
following methods. The results are as shown in Table 5-1 below.
[0212] Holding power
[0213] The pressure-sensitive adhesive tape having a width of 10 mm
was stuck to a phenol resin plate with the adhered area of 10
mm.times.20 mm under the conditions of 120.degree. C., 5
kg/cm.sup.2, and one minute, and after 20 minutes, was allowed to
stand at 80.degree. C. for 20 minutes. Then, the phenol resin plate
was hung down, a uniform load of 500 g was applied to a free end of
the pressure-sensitive adhesive tape, and the falling time (minute)
of the pressure-sensitive adhesive tape at 80.degree. C. was
measured.
[0214] Shear Adhesive strength
[0215] The pressure-sensitive adhesive tape of 10 mm.times.10 mm
was stuck between an aluminum plate of 0.5 mm.times.20 mm.times.100
mm and a PC plate of 2.0 mm.times.20 mm.times.100 mm, adhered under
the conditions of 120.degree. C., 5 kg/cm2, and 2 minutes, and
allowed to stand for 2 hours, and then the strength required for
the shearing was measured under the condition of a pulling rate of
10 mm/minute in the atmospheres of normal temperature (23.degree.
C., 65% RH) and a high temperature (80.degree. C.)
respectively.
[0216] Shock Resistance
[0217] The pressure-sensitive adhesive tape of 10 mm.times.10 mm
was stuck between a PC plate of 2 mm.times.60 mm.times.60 mm and a
SUS 304 plate of 0.5 mm.times.50 mm.times.50 mm, adhered under the
conditions of 120.degree. C., 5 kg/cm.sup.2, and one minute, after
allowing to stand for 2 hours, the assembly was fallen onto a
concrete from a height of 80 cm at 0.degree. C. and the number
required to be broken was measured.
6 TABLE 5-1 Shear Adhesive Holding Strength Shock Power
(kg/cm.sup.2) Resistance (minute) 23.degree. C. 80.degree. C.
(times) Ex 5-1 >120 32 10 >10 Ex 5-2 >120 35 12 >10 Ex
5-3 >120 27 8 >10 RE 5-1 >120 22 5 >10 RE 5-2 50 25 2
>10 CE 5-1 >120 28 3 2 Ex: Example RE: Reference Example CE:
Comparative Example
[0218] From the above Table 5-1, it can be seen that each of the
pressure-sensitive adhesive tapes of Examples 5-1 to 5-3 satisfies
the holding power (creep resistance) at a high temperature
(80.degree. C.) and the shear adhesive strength at normal
temperature and a high temperature and is excellent in the shock
resistance at a low temperature (0.degree. C.).
EXAMPLE 6-1
[0219] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 200.0 g (hydroxy
group: 0.41 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 20.51 g (acid group: 0.41 equivalent) of
succinic anhydride , and 102 mg of DBTO as a catalyst, the
temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 27 hours, a polyester having a weight average
molecular weight of 56,000 was obtained.
[0220] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.0 part (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
composition was coated on a PET film of 38 .mu.m in thickness by an
applicator, followed by drying at 130.degree. C. for 3 minutes, to
form a pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to obtain a
pressure-sensitive adhesive sheet.
EXAMPLE 6-2
[0221] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250 g (hydroxy
group: 0.51 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 51.8 g (acid group: 0.51 equivalent) of
sebacic acid and 127 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 60,000 was obtained.
[0222] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
composition was coated on a PET film of 38 .mu.m in thickness by an
applicator, followed by drying at 130.degree. C. for 5 minutes, to
form a pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 40 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to prepare a
pressure-sensitive adhesive sheet.
EXAMPLE 6-3
[0223] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 26.8 g (acid group: 0.26 equivalent) of
sebacic acid and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 31 hours, a polyester having a weight average
molecular weight of 74,000 was obtained.
[0224] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
composition was coated on a PET film of 38 .mu.m in thickness by an
applicator, followed by drying at 130.degree. C. for 5 minutes, to
form a pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 40 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to prepare a
pressure-sensitive adhesive sheet.
EXAMPLE 6-4
[0225] The polyester obtained in Example 6-3 was diluted with
toluene to a solid component concentration of 50% by weight. To 100
parts (solid components) of the polyester was added 2.0 parts
(solid components) of the hexamethylene diisocyanate addition
product of trimethylolpropane (Coronate HL, trade name, made by
Nippon Polyurethane Industry Co., Ltd.) to provide a
pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 60 .mu.m in
thickness by an applicator, followed by drying at 80.degree. C. for
10 minutes, to form a pressure-sensitive adhesive layer of 50 .mu.m
in thickness. Furthermore, a polyethylene film of 60 .mu.m in
thickness was stuck to the pressure-sensitive adhesive surface to
prepare a pressure-sensitive adhesive sheet of a base material-less
double faced pressure-sensitive adhesive type.
EXAMPLE 6-5
[0226] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 25.0 g (acid group: 0.25 equivalent) of
sebacic acid and 70 mg of titanium tetraisopropoxide as a catalyst,
the temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 24 hours, a polyester having a weight average
molecular weight of 59,000 was obtained.
[0227] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
composition was coated on a PET film of 38 .mu.m in thickness by an
applicator, followed by drying at 130.degree. C. for 5 minutes, to
form a pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to prepare a
pressure-sensitive adhesive sheet.
EXAMPLE 6-6
[0228] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 155.4 g of
polycarbonate diol (PLACCEL CD220PL, trade name, made by DAICEL
CHEMICAL INDUSTRIES, LTD.; hydroxy group value 56.1 KOH mg/g) and
84.1 g (total hydroxy groups: 0.24 equivalent) of polycaprolactone
dial (PLACCEL 220PL, trade name, made by DAICEL CHEMICAL
INDUSTRIES, LTD.; hydroxy group value: 55.9 KOH mg/g), 12.1 g (acid
group: 0.24 equivalent) of succinic anhydride and 59 mg of DBTO as
a catalyst, the temperature of the mixture was raised to
180.degree. C. while stirring in the presence of a small amount of
toluene as a reaction water discharging solvent, and the mixture
was maintained at the temperature. After a while, the outflow and
separation of water were observed and the reaction began to
proceed. By continuing the reaction for about 20 hours, a polyester
having a weight average molecular weight of 37,000 was
obtained.
[0229] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 3.0 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness by an applicator, followed by drying at 130.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 60 .mu.m in
thickness was stuck to the pressure-sensitive adhesive surface to
prepare a pressure-sensitive adhesive sheet.
EXAMPLE 6-7
[0230] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 218.1 g of
polycarbonate diol (PLACCEL CD220PL, trade name, made by DAICEL
CHEMICAL INDUSTRIES, LTD.; hydroxy group value 56.1 KOH mg/g) and
24.2 g of octanediol (total hydroxy groups: 0.55 equivalent), 27.9
g (acid group: 0.56 equivalent) of succinic anhydride, and 60 mg of
DBTO as a catalyst, the temperature of the mixture was raised to
180.degree. C. while stirring in the presence of a small amount of
toluene as a reaction water discharging solvent, and the mixture
was maintained at the temperature. After a while, the outflow and
separation of water were observed and the reaction began to
proceed. By continuing the reaction for about 22 hours, a polyester
having a weight average molecular weight of 24,000 was
obtained.
[0231] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 3.0 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness by an applicator, followed by drying at 130.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 60 .mu.m in
thickness was stuck to the pressure-sensitive adhesive surface to
prepare a pressure-sensitive adhesive sheet.
EXAMPLE 6-8
[0232] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 315.0 g (hydroxy
group: 0.31 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 55.4 KOH mg/g) and 16.3 g (acid group: 0.33 equivalent) of
succinic anhydride, the temperature of the mixture was raised to
180.degree. C. while stirring in the presence of a small amount of
toluene as a reaction water discharging solvent, and the mixture
was maintained at the temperature. After a while, the outflow and
separation of water were observed and the reaction began to
proceed. By continuing the reaction for about 40 hours, a polyester
having a weight average molecular weight of 39,000 was
obtained.
[0233] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 4.0 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness by an applicator, followed by drying at 130.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 60 .mu.m in
thickness was stuck to the pressure-sensitive adhesive surface to
prepare a pressure-sensitive adhesive sheet.
COMPARATIVE EXAMPLE 6-1
[0234] To a monomer mixture of 92 parts of butyl acrylate and 8
parts of acrylic acid were added 150 parts of toluene and 0.1 part
of azobisisobutronitrile to provide a mixed solution and the mixed
solution was solution-polymerized in a nitrogen gas atmosphere at
60.degree. C. for about 7 hours to provide a polymer solution. To
100 parts (solid components) of the polymer was added 2.0 parts
(solid components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a PET film of 38 .mu.m in
thickness by an applicator, followed by drying at 120.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m. Furthermore, a blend film composed of polyethylene and
polypropylene of 40 .mu.m in thickness was stuck to the
pressure-sensitive adhesive surface to prepare a pressure-sensitive
adhesive sheet.
COMPARATIVE EXAMPLE 6-2
[0235] In 150 parts of toluene were dissolved 100 parts of natural
rubber, 100 parts of an aliphatic petroleum resin (softening point
100.degree. C.), and 20 parts of a softening agent (polybutene) and
1.5 parts (solid components) of the tolylene diisocyanate addition
product of trim ethylolpropane (Coronate L, trade namet made by
Nippon Polyurethane Industry Co., Ltd.) was added to the solution
as a crosslinking agent to provide a pressure-sensitive adhesive
composition. The pressure-sensitive adhesive composition was coated
on a PET film of 38 .mu.m in thickness by an applicator, followed
by drying at 100.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to prepare a
pressure-sensitive adhesive sheet.
[0236] With respect to each of the pressure-sensitive adhesive
sheets obtained in Examples 6-1 to 6-8 and Comparative Examples 6-1
and 6-2, the releasing strength of a release liner and the adhesive
strength were measured by the following methods. The results are
shown in Table 6-1 below.
[0237] Measurement of Releasing Strength
[0238] The release liner was released from the pressure-sensitive
adhesive sheet by an Instron type tension tester at an atmospheric
temperature of 23.degree. C. and under the condition of a releasing
rate of 300 mm/minute, and the releasing strength was measured at a
releasing angle of 180 degree.
[0239] Measurement of Adhesive strength
[0240] The release liner was released from the pressure-sensitive
adhesive sheet, the sheet was stuck to an aluminum plate, and the
180 degree peel pressure-sensitive adhesive strength was measured
under the conditions of an atmospheric temperature of 23.degree.
C., a stuck time of 30 minutes, and a releasing rate of 300
mm/minute. With respect to the sample of Example 6-4, the
measurement was effected after backing a PET film of 38 .mu.m in
thickness, because the sample did not have a base material.
7 TABLE 6-1 Releasing Strength Adhesive Strength (g/50 mm width)
(g/20 mm width) Example 6-1 15 1,500 Example 6-2 20 1,300 Example
6-3 45 1,100 Example 6-4 15 1,100 Example 6-5 9 2,200 Example 6-6
10 2,300 Example 6-7 17 1,600 Example 6-8 25 1,700 C.Example 6-1
900 1,100 C.Example 6-2 800 1,300 C. Example: Comparative
Example
[0241] It can be seen from the results shown in the above Table 6-1
that each of the pressure-sensitive adhesive sheets obtained in
Examples 6-1 to 6-8 shows a small releasing strength which does not
give a hindrance to the releasing work and has a large adhesive
strength which is desired in the practical use although they use
release liners not subjected to a silicone release coating.
EXAMPLE 7-1
[0242] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 200.0 g (hydroxy
group: 0.41 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 20.51 g (acid group: 0.41 equivalent) of
succinic anhydride, and 102 mg of DBTO as a catalyst, the
temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 65,000 was obtained.
[0243] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 3 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive solution. The pressure-sensitive
adhesive solution was coated on a PET film of 38 .mu.m in thickness
by an applicator, followed by drying at 130.degree. C. for 5
minutes, to form a pressure-sensitive adhesive layer of 30 .mu.m in
thickness. Furthermore, the layer was subjected to aging in an
atmosphere of 50.degree. C. for 2 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 7-2
[0244] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.512 equivalent) of polycarbonate diol (PLACCEL CD21OPL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 37.44 g (acid group: 0.512 equivalent) of
adipic acid, and 127 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 72,000 was obtained.
[0245] After diluting the polyester with toluene to a solid
component concentration of 40% by weight, 3 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive solution. The solution was coated on
a PET film of 38 .mu.m in thickness by an applicator, followed by
drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 30 .mu.m in thickness.
Furthermore, the layer was subjected to aging in an atmosphere of
50.degree. C. for 2 days as post cure to prepare a
pressure-sensitive adhesive tape.
EXAMPLE 7-3
[0246] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 25.28 g (acid group: 0.25 equivalent) of
sebacic acid, and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of xylene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 20 hours, a polyester having a weight average
molecular weight of 55,000 was obtained.
[0247] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 3 parts (solid
components) of a hexamethylene diisocyanate trimer (isocyanurate)
(Coronate HX, trade name, made by Nippon Polyurethane Industry Co.,
Ltd.) per 100 parts (solid component) of the polyester was added
thereto as a crosslinking agent to provide a pressure-sensitive
adhesive solution. The solution was coated on a PET film of 38
.mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 30 .mu.m in thickness. Furthermore, the layer was
subjected to aging in an atmosphere of 50.degree. C. for 2 days as
post cure to prepare a pressure-sensitive adhesive tape.
EXAMPLE 7-4
[0248] To 100 parts (solid components) of the polyester obtained in
Example 7-3 was added 5 parts of trimethylolpropane triacrylate as
a substantial crosslinking agent to provide a pressure-sensitive
adhesive solution. The pressure-sensitive adhesive solution was
coated on a PET film of 38 .mu.m in thickness by an applicator,
followed by drying at 100.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 30 .mu.m in thickness.
Furthermore, the layer was irradiated with electron rays at 5 Mrad
to prepare a pressure-sensitive adhesive tape.
COMPARATIVE EXAMPLE 7-1
[0249] To 100 parts (solid components) of the polyester obtained in
Example 7-3 was added 2 parts (solid components) of diphenylmethane
diisocyanate (Millionate MT, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) as a crosslinking agent to provide
a pressure-sensitive adhesive solution. The pressure-sensitive
adhesive solution was coated on a PET film of 38 .mu.m in thickness
by an applicator, followed by drying at 130.degree. C. for 5
minutes, to form a pressure-sensitive adhesive layer of 30 .mu.m in
thickness. Furthermore, the layer was subjected to aging in an
atmosphere of 50.degree. C. for 2 days as post cure to prepare a
pressure-sensitive adhesive tape.
COMPARATIVE EXAMPLE 7-2
[0250] In 150 parts of toluene were dissolved 100 parts of a
styrene-isoprene-styrene block polymer (Carif lex TR1107, trade
name, made by Shell Chemical Co.), 50 parts of a petroleum resin,
and 1 part of a phenol series antioxidant to provide a
pressure-sensitive adhesive solution. The solution was coated on a
PET film of 38 .mu.m in thickness by an applicator, followed by
drying at 100.degree. C. for 3 minutes, to form a
pressure-sensitive adhesive layer of 30 .mu.m in thickness. Thus, a
pressure-sensitive adhesive tape was prepared.
[0251] With respect to each of the pressure-sensitive adhesive
tapes obtained in Examples 7-1 to 7-4 and Comparative Examples 7-1
and 7-2, the solvent-insoluble component, the self-adhesive
strength, and the removability were measured by the following
methods. Also, the evaluation of tack free (presence or absence of
tack) was carried out. These test results are shown in Table 7-1
below.
[0252] The measurement of the solvent-insoluble component was
carried out in the same manner as in "Measurement of
Solvent-Insoluble Component" in Example 2-4.
[0253] The measurement of the self-adhesive strength was carried
out by the same manner as in "Measurement of Self-adhesive
strength" in Comparative Example 3-2.
[0254] Measurement of Removability
[0255] At an atmospheric temperature of 23.degree. C., two
pressure-sensitive adhesive tapes each having a width of 20 mm and
a length of 150 mm were stuck to each other at the
pressure-sensitive adhesive surfaces of the central portions
thereof by a roller of 2 kg, and after storing for 24 hours at the
same temperature, the peeling strength was measured under the
conditions of a releasing rate of 300 mm/minute.
[0256] Evaluation of Tack Free
[0257] The pressure-sensitive adhesive surface of the
pressure-sensitive adhesive tape was contacted with a finger and
the case of feeling no tack was evaluated by "A", the case of
feeling tack was evaluated by "B".
8 TABLE 7-1 Self- Solvent- adhesive Remova- Insoluble Strength
bility Component (g/20 (g/20 mm Tack (weight %) mm width) width)
Free Ex 7-1 75 650 950 A Ex 7-2 81 580 870 A Ex 7-3 88 520 790 A Ex
7-4 66 620 850 A CE 7-1 15 4,580 5,320 A CE 7-2 0 1,920 2,350 B Ex:
Example, CE: Comparative Example
[0258] As is clear from the result shown of above Table 7-1, each
of the pressure-sensitive adhesive tapes in Examples 7-1 to 7-4
was, in spite of tack free, had a good self-adhesive strength and
also was excellent in the removability. On the other hand, the
pressure-sensitive tape of Comparative Example 7-1 had a large
self-adhesive strength but was inferior in the removability and the
pressure-sensitive adhesive tape of Comparative Example 7-2 had
tack and also was inferior in the removability.
EXAMPLE 8-1
[0259] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 200.0 g (hydroxy
group: 0.41 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 20.51 g (acid group: 0.41 equivalent) of
succinic anhydride, and 102 mg of DBTO as a catalyst, the
temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 27 hours, a polyester having a weight average
molecular weight of 56,000 was obtained.
[0260] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.0 part (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a polyurethane foam of 1.2 mm in
thickness by an applicator, followed by drying at 130.degree. C.
for 3 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 100 .mu.m
in thickness was stuck to the surface of the pressure-sensitive
adhesive layer to prepare a sealing material.
EXAMPLE 8-2
[0261] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.512 equivalent) of polycarbonate diol (PLACCEL CD210PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 115.0 KOH mg/g), 51.8 g (acid group: 0.512 equivalent) of
sebacic acid, and 127 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 30 hours, a polyester having a weight average
molecular weight of 60,000 was obtained.
[0262] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on an SBR foam of 0.3 mm in thickness by an applicator,
followed by drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the surface of the pressure-sensitive adhesive layer to prepare
a sealing material.
EXAMPLE 8-3
[0263] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.26 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 26.8 g (acid group: 0.26 equivalent) of
sebacic acid, and 62 mg of DBTO as a catalyst, the temperature of
the mixture was raised to 180.degree. C. while stirring in the
presence of a small amount of toluene as a reaction water
discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 31 hours, a polyester having a weight average
molecular weight of 74,000 was obtained.
[0264] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1.5 parts (solid
components) of the hexamethylene diisocyanate addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a polyurethane sheet of 0.5 mm
in thickness by an applicator, followed by drying at 130.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 100 .mu.m
in thickness was stuck to the surface of the pressure-sensitive
adhesive layer to prepare a sealing material.
EXAMPLE 8-4
[0265] The polyester obtained in Example 8-3 was diluted with
toluene to a solid component concentration of 50% by weight. To 100
parts (solid components) of the polyester was added 2.0 parts
(solid components) of the hexamethylene diisocyanate addition
product of trimethylolpropane (Coronate HL, trade name, made by
Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent to
provide a pressure-sensitive adhesive composition. The
pressure-sensitive adhesive composition was coated on a
polyurethane foam of 1.2 mm in thickness by an applicator, followed
by drying at 80.degree. C. for 10 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the surface of the pressure-sensitive adhesive layer to prepare
a sealing material.
COMPARATIVE EXAMPLE 8-1
[0266] To a monomer mixture of 92 parts of butyl acrylate and 8
parts of acrylic acid were added 150 parts of toluene and 0.1 part
of azobisisobutyronitrile to provide a mixed solution and the mixed
solution was solution-polymerized in a nitrogen gas atmosphere at
60.degree. C. for about 7 hours to provide a polymer solution. To
100 parts (solid components) of the polymer was added 2.0 parts
(solid components) of the tolylene diisocyanate addition product of
trimethylolpropane (Coronate L, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The pressure-sensitive
adhesive composition was coated on a polyurethane foam of 1.2 mm in
thickness by an applicator, followed by drying at 120.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m. Furthermore, a blend film of polyethylene and polypropylene
having a thickness of 50 .mu.m was stuck to the pressure-sensitive
adhesive surface to prepare a sealing material.
COMPARATIVE EXAMPLE 8-2
[0267] In 150 parts of toluene were dissolved 100 parts of natural
rubber, 100 parts of an aliphatic petroleum resin (softening point
100.degree. C.), and 20 parts of a softening agent (polybutene),
and 1.5 parts (solid components) of the tolylene diisocyanate
addition product of trimethylolpropane (Coronate L, trade name,
made by Nippon Polyurethane Industry Co., Ltd.) was added to the
solution as a crosslinking agent to provide a pressure-sensitive
adhesive composition. The pressure-sensitive adhesive composition
was coated on a polyurethane form of 1.2 mm in thickness by an
applicator, followed by drying at 100.degree. C. for 5 minutes, to
form a pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 60 .mu.m in thickness was stuck
to the pressure-sensitive adhesive surface to prepare a sealing
material.
[0268] With respect to each of the sealing materials obtained in
Examples 8-1 to 8-4 and Comparative Examples 8-1 and 8-2, the
adhesive strength, and the releasing strength of the release liner
were measured by the following methods. The results are as shown in
Table 8-1 below.
[0269] Measurement of Adhesive strength
[0270] In an atmosphere of 23.degree. C., 65% RH, the release liner
was released from the sealing material, the sealing material was
stuck to an aluminum plate, and after 30 minutes, the 180 degree
peel adhesive strength was measured under the condition of a
pulling rate of 300 mm/minute.
[0271] Measurement of Releasing Strength
[0272] In an atmosphere of 23.degree. C., 65% RH, the release liner
was released from the sealing material under the condition of a
pulling rate of 300 mm/minute to measure the releasing
strength.
9 TABLE 8-1 Adhesive Strength Releasing Strength (g/20 mm width)
(g/50 mm width) Example 8-1 1,300 20 Example 8-2 1,000 30 Example
8-3 1,000 50 Example 8-4 1,200 20 C.Example 8-1 1,000 900 C.Example
8-2 1,200 850 C.Example: Comparative Example
[0273] It is clear from the result of Table B-1 that each of the
sealing materials of Examples 8-1 to 8-4 shows a small releasing
strength giving no hindrance to the releasing work and has a large
adhesive strength desired for practical use in spite of using a
release liner not subjected to a silicone release coating. On the
other hand, it can be seen that in the sealing materials of
Comparative Examples 8-1 and 8-2, the adhesive strength is large
but because the releasing strength of the release liner is too
large, it gives an hindrance to the releasing work.
[0274] Also, because the sealing materials of Examples 8-1 to 8-4
do not contain a silicone compound not only in the release liner
but also in the sealing base material and the layer of the
pressure-sensitive adhesive composition, when the sealing material
is used as a connecting material for HDD, a siloxane gas does not
generates in the inside of HDD, and a corrosion of the inside of
HDD, an erroneous action of HDD, a head crash and the like caused
by the gas are not caused, and the original sealing function based
on the sealing base material, that is, the sealing function based
on the elastic effect of a foamed material, etc., can be exhibited
more effectively together with the good adhesive strength described
above.
EXAMPLE 8-5
[0275] The pressure-sensitive adhesive composition obtained in
Example 8-1 was coated on an aluminum sheet of 80 .mu.m in
thickness by an applicator, followed by drying at 130.degree. C.
for 3 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a polyethylene film of 100 .mu.m
in thickness was stuck to the surface of the pressure-sensitive
adhesive layer to prepare a sealing material.
EXAMPLE 8-6
[0276] The pressure-sensitive adhesive composition obtained in
Example 8-2 was coated on an aluminum laminate sheet (a laminate
sheet formed by vapor-depositing a metallic aluminum at a thickness
of 30 .mu.m on a polyethylene phthalate film of 50 .mu.m in
thickness) of 80 .mu.m in thickness by an applicator, followed by
drying at 130.degree. C. for 5 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 100 .mu.m in thickness was
stuck to the surface of the pressure-sensitive adhesive layer to
prepare a sealing material.
EXAMPLE 8-7
[0277] The pressure-sensitive adhesive composition obtained in
Example 8-3 was coated on a fluorine resin (PTFE) sheet of 100
.mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness. Furthermore, a polyethylene film of
100 .mu.m in thickness was stuck to the surface of the
pressure-sensitive adhesive layer to prepare a sealing
material.
EXAMPLE 8-8
[0278] The pressure-sensitive adhesive composition obtained in
Example 8-4 was coated on a fluorine resin-coated sheet (a sheet
obtained by coating a fluorine resin (PTFE) at a thickness of 5
.mu.m on a polyethylene terephthalate film of 50 .mu.m in
thickness) of 55 .mu.m in thickness by an applicator, followed by
drying at 80.degree. C. for 10 minutes, to form a
pressure-sensitive adhesive layer of 50 .mu.m in thickness.
Furthermore, a polyethylene film of 100 .mu.m in thickness was
stuck to the surface of the pressure-sensitive adhesive layer to
prepare a sealing material.
COMPARATIVE EXAMPLE 8-3
[0279] The pressure-sensitive adhesive composition obtained in
Example 8-1 was coated on an aluminum sheet of 50 .mu.m in
thickness by an applicator, followed by drying at 120.degree. C.
for 5 minutes, to form a pressure-sensitive adhesive layer of 50
.mu.m in thickness. Furthermore, a releasing paper (subjected to a
silicone release coating) of 130 .mu.m in thickness was stuck to
the surface of the pressure-sensitive adhesive layer to prepare a
sealing material.
COMPARATIVE EXAMPLE 8-4
[0280] The pressure-sensitive adhesive composition obtained in
Example 8-1 was coated on a polyethylene terephthalate film of 50
.mu.m in thickness by an applicator, followed by drying at
130.degree. C. for 3 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness. Furthermore, a polyethylene film of
100 .mu.m in thickness was stuck to the surface of the
pressure-sensitive adhesive layer to prepare a sealing
material.
[0281] With respect to each of the sealing martials of Examples 8-5
to 8-8 and Comparative Examples 8-3 and 8-4, the adhesive strength
and the releasing strength of the release liner were measured by
the same methods as described above.
[0282] The results are as shown in Table 8-2 below.
10 TABLE 8-2 Releasing Adhesive Strength Strength (g/20 mm width)
(g/50 mm width) Example 8-5 1,350 20 Example 8-6 1,000 30 Example
8-7 1,000 50 Example 8-8 1,200 20 C.Example 8-3 1,000 30 C.Example
8-4 1,000 20 C. Example: Comparative Example
[0283] As is clear from the results of Table 8-2 above, it can be
seen that each of the sealing materials of Examples 8-5 to 8-8
shows, in spite of using a release liner not subjected to a
silicone release coating, shows a small releasing strength giving
no hindrance to the releasing work as the case of the sealing
material using the release liner subjected to a silicone release
coating (Comparative Example 8-3) and also has a large adhesive
strength desired for practical use.
[0284] Also, because each of the sealing materials of Examples 8-5
to 8-8 is different from the sealing material of Comparative
Example 8-3, does not contain a silicone compound in the release
liner, and does not contain a silicone compound in the sealing base
material and the layer of the pressure-sensitive adhesive
composition, when the sealing material is used as a connecting
material for HDD, a siloxane gas does not generate in the inside of
HDD and there are no possibilities of causing the corrosion of the
inside of HDD, an erroneous action, a head crush, etc. Furthermore,
because a material having a high moisture proof effect is used as
the sealing base material, the moisture proof effect is far high as
compared with the sealing material of Comparative Example 8-4, the
sealing function based on the moisture proofing effect can be more
effectively exhibited together with the above-described good
adhesive strength.
EXAMPLE 9-1
[0285] In a four-neck separable flask equipped with a stirrer, a
thermometer, and a water separator were placed 250.0 g (hydroxy
group: 0.25 equivalent) of polycarbonate diol (PLACCEL CD220PL,
trade name, made by DAICEL CHEMICAL INDUSTRIES, LTD.; hydroxy group
value 56.1 KOH mg/g), 25.28 g (acid group: 0.25 equivalent) of
sebacic acid, and 62 mg (0.1 equivalent %) of DBTO as a catalyst,
the temperature of the mixture was raised to 180.degree. C. while
stirring in the presence of a small amount of toluene as a reaction
water discharging solvent, and the mixture was maintained at the
temperature. After a while, the outflow and separation of water
were observed and the reaction began to proceed. By continuing the
reaction for about 25 hours, a polyester having a weight average
molecular weight of 72,000 was obtained.
[0286] After diluting the polyester with toluene to a solid
component concentration of 50% by weight, 1 part (solid components)
of the hexamethylene diisocyanate trimer addition product of
trimethylolpropane (Coronate HL, trade name, made by Nippon
Polyurethane Industry Co., Ltd.) per 100 parts (solid component) of
the polyester was added thereto as a crosslinking agent to provide
a pressure-sensitive adhesive composition. The composition was
coated on one surface of a PET film of 38 .mu.m in thickness as an
insulating base material by an applicator, followed by drying at
130.degree. C. for 5 minutes, to form a pressure-sensitive adhesive
layer of 50 .mu.m in thickness. Thus, a reinforcing sheet was
prepared.
EXAMPLE 9-2
[0287] A reinforcing sheet was prepared in the same manner as in
Example 9-1 except that the thickness of the adhesive layer was
changed to 20 .mu.m.
EXAMPLE 9-3
[0288] By following the same procedure as Example 9-1 except that
the used amount of the hexamethylene diisocyanate trimer addition
product of trimethylolpropane (Coronate HL, made by Nippon
Polyurethane Industry Co., Ltd.) as the crosslinking agent was
changed to 1.5 parts, a pressure-sensitive composition was
prepared, and a reinforcing sheet having the layer of the
pressure-sensitive adhesive composition having a thickness of 50
.mu.m was prepared.
EXAMPLE 9-4
[0289] A reinforcing sheet was prepared in the same manner as in
Example 9-3 except that the thickness of the pressure-sensitive
adhesive layer was changed to 20 .mu.m.
COMPARATIVE EXAMPLE 9-1
[0290] After diluting a thermoplastic copolymerized polyester resin
(Vylon #300, trade name, made by TOYOBO CO., LTD.) with toluene to
a solid component concentration of 40% by weight, 2 parts (solid
components) of the hexamethylene diisocyanate trimer addition
product of trimethylolpropane (Coronate HL, trade name, made by
Nippon Polyuethane Industry Co., Ltd.) was added thereto per 100
parts (solid components) of the polyester as a crosslinking agent
to provide a pressure-sensitive adhesive composition. Then, using
the composition, a reinforcing sheet having the adhesive layer of
50 .mu.m in thickness was prepared in the same manner as in Example
9-1.
COMPARATIVE EXAMPLE 9-2
[0291] A reinforcing sheet was prepared in the same manner as in
Comparative Example 9-1 except that the thickness of the adhesive
layer was changed to 20 .mu.m.
[0292] With respect to each of the reinforcing sheets obtained in
Examples 9-1 to 9-4 and Comparative Examples 9-1 and 9-2, the
measurement of the solvent-insoluble component of the
pressure-sensitive adhesive layer and the measurement of the
adhesive strengths (the adhesive strength to an insulating layer
(polyester film) constituting a tape electric wire and the adhesive
strength to a tin-plated electrically conductive wire) at normal
temperature (23.degree. C.) and at a low temperature (0.degree. C.)
were measured by the following methods.
[0293] The measurement of the solvent-insoluble component was
carried out by the same manner as in "Measurement of
Solvent-Insoluble Component" in Example 2-4.
[0294] Measurement of Adhesive strength
[0295] The reinforcing sheet was stuck to a polyester film
(insulating layer) and a tin-placed conductive wire as adherends
each under the conditions of 150.degree. C., 1 kg/cm.sup.2, and 2
seconds in an atmosphere of normal temperature (23.degree. C.) or a
low temperature (0.degree. C.), and the 180 degree peel adhesive
strength was measured under the condition of the releasing rate of
100 mm/minute.
11 TABLE 9-1 Solvent- Insoluble Adhesive strength (kg/cm) Component
Polyester Film Tin-Plated Wire (wt. %) 23.degree. C. 0.degree. C.
23.degree. C. 0.degree. C. Ex 9-1 17 1.6 1.0 100 110 Ex 9-2 18 1.3
1.6 70 90 Ex 9-3 55 1.7 2.2 140 140 Ex 9-4 51 1.4 1.0 110 110 CE
9-1 35 1.5 0.2 150 30 CE 9-2 37 1.4 0.1 130 10 Ex: Example, CE:
Comparative Example
[0296] As is clear from the results shown in Table 9-1 above, it
can be seen that each of the reinforcing sheets of Examples 9-1 to
9-4 of the present invention shows a very excellent adhesive fore
to the insulating layer (polyester film) and the tin-placed
electrically conductive wire constituting a tape electric wire
under both the normal temperature atmosphere and the
low-temperature atmosphere.
EXAMPLE 10-1
[0297] In a reaction vessel equipped with a thermometer, a stirrer,
and a water separator were placed 100 parts of polycarbonate diol
(PLACCEL CD220PL, trade name, made by DAICEL CHEMICAL INDUSTRIES,
LTD., hydroxy group value 56.1 KOH mg/g), 10.1 parts of sebacic
acid, and 0.025 part of DBTO, and the temperature of the mixture
was raised to 180.degree. C. with stirring in the presence of
toluene as a reaction water discharging solvent. After a while, the
outflow and the separation of water were observed. By continuing
the reaction for about 24 hours, a solution of a polyester series
polymer having a weight average molecular weight of 60,000 was
obtained.
[0298] To the solution of the polyester series polymer were added
30 parts of a terpenephenol resin having a softening point of
115.degree. C. and 2 parts of the hexamethylene diisocyanate
addition product of trimethylolpropane per 100 parts of the solid
components thereof, followed by mixing, to provide a
pressure-sensitive adhesive solution. Then, the pressure-sensitive
adhesive solution was coated on one surface of a polyester film of
188 .mu.m in thickness at a dry thickness of 50 .mu.m, followed by
drying at 120.degree. C. for 2 minutes, to prepare a reinforcing
sheet.
EXAMPLE 10-2
[0299] By following the same procedure as Example 10-1 except that
20 parts of a rosinphenol resin having a softening point of
145.degree. C. was used in place of 30 parts of the terpenehenol
resin having a softening point of 115.degree. C., a
pressure-sensitive adhesive solution was prepared, and using the
solution, a reinforcing sheet was prepared.
EXAMPLE 10-3
[0300] By following the same procedure as Example 10-1 except that
50 parts of a coumarone-indene resin having a softening point of
120.degree. C. was used in place of 30 parts of the terpenehenol
resin having a softening point of 115.degree. C., a
pressure-sensitive adhesive solution was prepared and using the
solution, a reinforcing sheet was prepared.
COMPARATIVE EXAMPLE 10-1
[0301] To the solution of the polyester series polymer obtained in
Example 10-1 was added 2 parts of the tolylene diisocyanate
addition product of trimethylolpropane per 100 parts of the solid
components thereof, followed by mixing, to provide an adhesive
solution. Then, using the adhesive solution, a reinforcing sheet
was prepared in the same manner as in Example 1.
COMPARATIVE EXAMPLE 10-2
[0302] By following the same procedure as in Example 10-1 except
that 30 parts by weight of a terpenehenol resin having a softening
point of 50.degree. C. was used in place of 30 parts of the
tetpenehenol resin having a softening point of 115.degree. C., an
adhesive solution was prepared, and using the solution, a
reinforcing sheet was prepared.
COMPARATIVE EXAMPLE 10-3
[0303] In a reaction vessel equipped with a condenser, a nitrogen
introducing tube, a thermometer, and a stirrer were placed 50 parts
of ethyl acetate and 50 parts of toluene as solvents, 50 parts of
2-ethylhexyl acrylate, 45 parts of n-butyl acrylate, 4.9 parts of
acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and 0.1 part of
2,2'-azobis-isobutyronitrile, the polymerization was carried out in
a nitrogen gas stream to provide a solution of an acrylic polymer
having a weight average molecular weight of 700,000.
[0304] To the solution of the acrylic polymer were added 30 parts
of a terpenephenol resin having a softening point of 115.degree. C.
and 2 parts of the hexamethylene diisocyanate addition product of
trimethylolpropane per 100 parts of the solid components thereof,
followed by mixing, to provide a pressure-sensitive adhesive
solution. Then, using the solution, a reinforcing sheet was
prepared in the same manner as in Example 10-1 .
[0305] About each of the reinforcing sheets prepared in Examples
10-1 to 10-3 and Comparative Examples 10-1 to 10-3, the adhesive
strengths to a tin-plated electrically conductive wire and an
insulating layer (polyester film) for constituting a tape electric
wire in an atmosphere of 0, 25 or 80.degree. C. were measured as
follows. The results are as shown in Table 10-1 below.
[0306] Measurement of Adhesive strength to Tin-Plated Conductive
Wire
[0307] On the pressure-sensitive adhesive layer of the reinforcing
sheet of 50 mm.times.200 mm were placed 6 tine-plated spright angle
conductive wires (each of 0.1 mm.times.0.8 mm.times.250 mm) and
after heat-press adhering under the conditions of 160.degree. C., 5
kg/cm.sup.2, and one minute, the strength required for releasing
one conductive wire was measured. The measurement was carried out
in an atmosphere of 0.degree. C., 25.degree. C. (65% RH) or
80.degree. C. under the conditions of a releasing rate of 100
mm/minute and a releasing angle of 180 degree.
[0308] Measurement of Adhesive strength to Insulating Layer
(Polyester Film)
[0309] On the pressure-sensitive adhesive layer of the reinforcing
sheet of 50 mm.times.200 mm was placed one sheet of a polyester
film of 0.1 mm.times.70 mm.times.250 mm, after heat-press adhering
under the conditions of 160.degree. C., 5 kg/cm.sup.2, and one
minute, the laminate was cut into a width of 1 cm, and the strength
required to release the polyester film of 1 cm in width was
measured. The measurement was carried out in an atmosphere of
0.degree. C., 25.degree. C. (65% RH), or 80.degree. C., under the
conditions of the releasing rate of 100 mm/minute and the releasing
angle of 180 degree.
12 TABLE 10-1 Tin-Plated Wire Polyester Film Adhesive strength
Adhesive strength (g/0.8 mm) (kg/cm) 0.degree. C. 25.degree. C.
80.degree. C. 0.degree. C. 25.degree. C. 80.degree. C. Ex 10-1 100
130 90 1.0 1.5 0.8 Ex 10-2 90 140 100 0.9 1.4 1.0 Ex 10-3 140 140
80 0.9 1.3 0.9 CE 10-1 70 120 30 0.4 1.0 0.4 CE 10-2 70 100 20 0.4
1.0 0.3 CE 10-3 30 100 80 0.2 0.8 0.5 Ex: Example, CE: Comparative
Example
[0310] It can be seen from the results of Table 10-1 above that
each of the reinforcing sheets of Examples 10-1 to 10-3 of the
present invention shows excellent adhesive strength to the
insulating layer (polyester film) and the electrically conductive
wires (tin-placed conductive wires) constituting a tape electric
wire at each atmosphere of a low-temperate (0.degree. C.), normal
temperature (25.degree. C.) or a high temperature (80.degree.
C.).
EXAMPLE 11-1
[0311] A polyethylene (viscosity average molecular weight 300,000)
containing 0.4 part of an antioxidant was extrusion-laminated on a
glassine paper having a thickness of 50 .mu.m and a basic weight of
80 g at a thickness of 20 .mu.m to provide a tape base
material.
[0312] The pressure-sensitive adhesive composition obtained in
Example 1-1 was uniformly coated on the back surface of the
above-described tape base material by a doctor blade method,
followed by drying, to form a pressure-sensitive adhesive layer of
20 .mu.m in thickness, whereby a pressure-sensitive adhesive tape
for printing was obtained.
[0313] Furthermore, to 100 parts of a polyethylene having a
viscosity average molecular weight of 8,000 was added 100 parts of
carbon, followed by uniformly mixing at about 200.degree. C., and
the uniform -dispersion was uniformly coated on a polyethylene
terephthalate film of 6 .mu.m in thickness by a gravure coating
machine for hot melt to provide a pattern-forming ink ribbon having
coating of 0.8 .mu.m in thickness.
[0314] Using the pressure-sensitive adhesive tape for printing and
the ink ribbon, printing was carried out by a heat-transfer
printer.
EXAMPLE 11-2
[0315] Printing was carried out in the same manner as in Example
11-1 except for using a base material film of 100 .mu.m in
thickness, obtained by uniformly kneading 20 parts of titanium
white with a polyethylene (viscosity average molecular weight
500,000) containing 0.2 part of an antioxidant and inflation
molding the kneaded mixture, as the tape base material.
EXAMPLE 11-3
[0316] The pressure-sensitive adhesive composition obtained in
Example 1-1 was uniformly coated on a polyethylene film having a
viscosity average molecular weight of 500,000 and a thickness of 5
.mu.m by a doctor blade method, followed by drying, to form a
pressure-sensitive adhesive layer of 3 .mu.m in thickness. A
generally commercially available heat-sensitive coloring paper was
laminated onto the pressure-sensitive adhesive tape to provide a
base material layer of a printing pressure-sensitive adhesive tape.
With respect to the other portions, the same procedure as in
Example 11-1 was followed to prepare a pressure-sensitive adhesive
layer. Also, the formation of the printing pattern was carried out
by a thermal printer.
[0317] Evaluation Test
[0318] The printing tapes obtained in Examples 11-1 to 11-3 were
evaluated in terms of the tape re-winding property, the running
property by a heat-transfer printer, the printability, and the
handling properties as label. The results showed that all cases
were good.
INDUSTRIAL APPLICABILITY
[0319] As described above, the present invention can provide a
pressure-sensitive adhesive composition and the pressure-sensitive
adhesive sheets thereof, which have a large adhesive strength in
spite of high elasticity and tack free, can exhibit both the good
adhesive workability and the good adhesive property, are excellent
in the heat resistance, and also are excellent in properties of
retaining and fixing articles.
[0320] In particular, by using the polymer having the polycarbonate
structure as the base polymer and subjecting the polymer to a
crosslinking treatment with a crosslinking agent, etc., the
above-described pressure-sensitive adhesive composition and
pressure-sensitive adhesive sheets thereof greatly excellent in the
characteristics such as the heat resistance and the durability can
be provided and they can be more developed in various fields as
pressure-sensitive adhesive products of new construction.
[0321] Also, the present invention can provide, by properly
crosslinking the polymer having the polycarbonate structure, a
pressure-sensitive adhesive composition and a pressure-sensitive
adhesive sheet thereof showing an excellent self-adhering property
in addition to the characteristics such as the heat resistance and
the durability.
[0322] Also, in the present invention, by using the specific
polymer having the polycarbonate structure as the main component
and crosslinking the polymer to a specific level, a
pressure-sensitive adhesive composition not substantially showing
tack but has the excellent self-adhesive strength and being
excellent in the removability and a pressure-sensitive adhesive
sheet thereof can be provided.
[0323] Furthermore, by using an acrylic polymer having a glass
transition point of -10.degree. C. or lower together with the
polymer having the polycarbonate structure, a pressure-sensitive
adhesive composition showing very good adhesive characteristics to
various adherends and being excellent in the creep characteristics
and the long-term durability and a pressure-sensitive adhesive tape
thereof can be provided. Also, similarly, a pressure-sensitive
adhesive composition satisfying the creep resistance and the
adhesive property in a high temperature region and being excellent
in the shock resistance at a low temperature and a
pressure-sensitive sheets thereof, can be provided by using a resin
having a softening point of 80.degree. C. or higher together with
the polymer described above.
[0324] Moreover, in the present invention, by using a release liner
made up of a polyethylene film, a polypropylene film, etc., which
is not subjected to a silicone release coating to the layer of the
pressure-sensitive adhesive composition of the above-described
construction containing the polymer having the polycarbonate
structure, the pressure-sensitive adhesive sheets having a good
releasing property without containing a silicone and exhibiting a
large adhesive strength can be provided. The products can be very
advantageously used as pressure-sensitive adhesive sheets suitably
used for computer instruments which are liable to cause problems in
the presence of a silicone.
[0325] Also, in the present invention, by forming the layer of the
pressure-sensitive adhesive composition containing the polymer
having the polycarbonate structure on one surface of a base
material and constituting at least the back side of the base
material with a polyolefin such as polyethylene, polypropylene,
etc., a pressure-sensitive adhesive sheet which can be wound in
roll forms without inserting a release liner can be provided. This
product can be advantageously used for computer instruments, etc.,
which are liable to cause problems by the existence of silicone, as
a pressure-sensitive sheet which does not have a release liner, do
not need to apply a release coating to the back side of the base
material with a silicone compound, and contain substantially no
silicone compound.
[0326] Also, in the constitution in which the layer of the specific
pressure-sensitive adhesive composition is formed on a sealing base
material according to the present invention, a release liner which
is not subjected to a silicone release coating can be used, and it
is unnecessary to subject the back side of the sealing base
material to a silicone release coating. Thus, a sealing material
having a good releasing property to a release liner and the back
surface of itself, showing a large adhesive strength, and being
excellent in the original sealing function can be provided as a
sealing material containing substantially no silicone compound and
suitable for HDD, etc.
[0327] Furthermore, in the present invention, by using the specific
polyester having the polycarbonate structure as the base polymer
for the pressure-sensitive adhesive layer which is formed on one
surface of an insulating base material, the reinforcing sheet
excellent in the adhesive property with a tape electric wire
(insulating layer and conductive wires) at not only a normal
temperature but also a low-temperature environment of about
0.degree. C. or less can be provided and by using the specific
resin together with the specific polyester, the reinforcing sheet
excellent in the adhesive property to the tape electric wire not
only in a normal temperature atmosphere but also in a
low-temperature atmosphere and a high-temperature atmosphere can be
provided.
[0328] Also, in the present invention, by using the specific
pressure-sensitive adhesive sheets as pressure-sensitive adhesive
sheets for printing, the printing pressure-sensitive adhesive
sheets excellent in the tape re-winding property, the running
property in a heat-transfer printer, the printability, and the
handling properties as label can be provided.
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