JP2003213237A - Adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermo-activable adhesive of thermally positionable- repositionable type, having enhanced reliability, by keeping relatively high adhesion for a long period or improving the adhesion. <P>SOLUTION: This adhesive composition contains an adhesive polymer and at least one kind of crystalline polymer selected from the group consisting of a crystalline carbonate and a 1,9-nonanediol-containing crystalline polyester polyol. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to adhesive compositions and, more particularly, to adhesive compositions having the properties of both heat activated adhesives and heat releasable adhesives.

[0002]

2. Description of the Related Art As one of the categories of adhesive compositions,
As is well known, there are pressure sensitive adhesive compositions. This pressure-sensitive adhesive composition is also called an adhesive. Since the pressure-sensitive adhesive has tack at room temperature, it can generally exhibit practically immediate adhesive strength by simply applying pressure without being activated by water, a solvent, heat or the like. An example of such a pressure-sensitive adhesive is disclosed in JP-A-2000-186265, in which 50 to 5% by weight of an acrylic polymer which does not contain an acid component and has a glass transition point of -10 ° C or lower, and a fat 50-95% by weight of a group-based polycarbonate diol-containing polyester polymer.

On the other hand, examples of adhesive compositions include those disclosed in JP-A-20
Some of them, as disclosed in Japanese Patent Publication No. 01-316658, melt by an external heat or develop a tack to enable joining. Such an adhesive composition is also called a heat activated adhesive. Some heat activated adhesives exhibit removability as disclosed in US Pat. No. 5,192,612. Such a releasable heat-activatable adhesive includes a pressure-sensitive adhesive base resin containing a tacky polymer (for example, an acrylic polymer) and a crystalline polymer (for example, poly It includes a detackifying resin containing caprolactone) and detackifying particles made of inorganic particles (for example, silica).

Also, unlike the above, some heat-activatable adhesives exhibit removability by heating, and may be peeled from the adherend after final adhesion, during use, or after use is completed. It is possible. An example of such a heat-peelable heat-activatable adhesive is disclosed in US Pat. No. 5,412,035, which is an adhesive that is effective at at least one temperature in the range of 20 to 40 ° C. (eg, , Rubber-based adhesives, acrylic-based adhesives) and crystalline polymers (for example, having 14 to 2 carbon atoms).
It is composed of a side chain crystalline polymer containing (meth) acrylate having two alkyl groups. A similar type of heat-activatable adhesive is also disclosed in JP-A-2000-119624. This heat-removable heat-activatable adhesive uses polycaprolactone as a crystalline polymer. Further, the pressure-sensitive adhesive contains a pressure-sensitive adhesive polymer containing a hydroxyl group and a phenyl group, and at a temperature equal to or higher than the melting point of the above polycaprolactone, it becomes extremely compatible with polycaprolactone. Such a heat-activatable adhesive exhibits almost no tackiness due to crystallized polycaprolactone at room temperature, but can exhibit a very high adhesive strength after being heated and melting the polycaprolactone.

[0005]

The adhesive strength as described above is maintained for as long as possible not only immediately after heating,
Or it is desirable to be improved. However, polycaprolactone is relatively easily hydrolyzed, and it may be difficult to maintain / improve the adhesive strength for a long period of time as it is. Therefore, an object of the present invention is to provide a heat-releasing type heat-activatable adhesive that maintains or improves a relatively high adhesive force over a long period of time and has improved reliability.

[0006]

According to the present invention, the above object is to provide at least one crystal selected from the group consisting of an adhesive polymer, a crystalline polycarbonate and a crystalline polyester polyol containing 1,9-nonanediol. And an adhesive composition comprising a hydrophilic polymer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to embodiments. The adhesive composition of the present invention generally comprises a tacky polymer and a crystalline polymer. The tacky polymer exhibits tackiness or tackiness at room temperature of about 25 ° C., and is compatible with the crystalline polymer at a temperature equal to or higher than the melting point of the crystalline polymer. Typical examples of adhesive polymers are acrylic polymers, nitrile-butadiene copolymers such as acrylonitrile-butadiene rubber (NBR), styrene-butadiene copolymers such as styrene-butadiene rubber (SBR), and amorphous. Polyurethanes and silicone polymers, etc.
Alternatively, they can be used as a mixture of two or more kinds.

A preferred tacky polymer is a polymer having (a) a hydroxyl group and (b) a phenyl group in the molecule, and can effectively enhance the compatibility with the above-mentioned crystalline polymer. . Further, the adhesive polymer may be capable of being crosslinked by irradiation with electromagnetic waves including ultraviolet rays or electron beams and / or by heating, if necessary.
In this case, the adhesive polymer includes a benzophenone group, an ethylenically unsaturated group, a group other than the groups (a) and (b) above,
Crosslinking reactivity is imparted by also including (c) a crosslinkable functional group typified by an epoxy group or a carboxyl group. Alternatively, the adhesive composition may further include a crosslinking component through which the tacky polymer can be crosslinked. The crosslinking component is not particularly limited as long as it is a bifunctional compound that can react with the above-mentioned crosslinking functional group. Such compounds usually consist of monomers or oligomers.

The above-mentioned suitable tacky polymer is usually 50% by mass or more, and preferably 60% by weight based on the whole tacky polymer.
It is contained by mass% or more, and more preferably 70 mass% or more. Therefore, unless the object and effect of the present invention are impaired,
The use of other tacky polymers that do not have (a) hydroxyl groups, (b) phenyl groups and the desired (c) crosslinkable functional groups is also acceptable.

The preferred tacky polymers mentioned above are usually copolymers derived from a mixture of the monomers mentioned below: (A) a monomer having a hydroxyl group in the molecule (B) an phenyl group in the molecule The monomer (C) having in (1) may be converted into a hydroxyl group and a phenyl group by reacting a monomer having a crosslinkable functional group in the molecule or a carboxyl group in the molecule. The above copolymer can be produced by a well-known and commonly used method, for example, solution polymerization.

The above-mentioned basic units derived from the monomer (A) having a hydroxyl group in the molecule and the monomer (B) having a phenyl group in the molecule are usually contained in the adhesive polymer in a mass percentage of 20 to 100%. , Preferably 30 to 10
It occupies 0%, more preferably 40 to 100%. When the proportion of the basic unit in the adhesive polymer is relatively small,
The tacky polymer becomes difficult to be compatible with the crystalline polymer. In addition, the adhesive polymer contains the above basic unit in a mass percentage of 42.
If it has 100% to 100%, it has tackiness or tack advantageous for pressure-bonding with an adherend.

The basic partial unit derived from the monomer (A) having a hydroxyl group in the molecule is usually 0.5% or more, preferably 1% by mole in the adhesive polymer.
% Or more, more preferably 5 to 25%. When the ratio of the basic partial unit in the tacky polymer is relatively low, the tacky polymer becomes difficult to be compatible with the crystalline polymer. On the other hand, when the ratio of the basic unit in the adhesive polymer is relatively large, it becomes difficult to effectively press-bond the adherend to the adherend.

Further, the partial unit derived from the monomer (C) having a crosslinkable functional group in the molecule is usually 0.5 to 15% by weight in the adhesive polymer, preferably 0.7.
-10%, more preferably 1-7%.

In the present invention, the molecular weight of the tacky polymer is not particularly limited as long as the object and effects of the present invention are achieved, but it usually has a weight average molecular weight of 10,000 to 1,000,000.

A desirable basic structure of each of the above-mentioned monomers is a (meth) acrylic monomer, and an acrylic adhesive polymer can be derived. More specifically, examples of the (meth) acrylic monomer having a hydroxyl group in the molecule include 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxyethyl methacrylate. , 2-hydroxypropyl methacrylate and 2-hydroxy-3
-Phenoxypropyl acrylate and the like are included. In particular, 2-hydroxy-3-phenoxypropyl acrylate has both a hydroxyl group and a phenyl group in the molecule, so that the compatibility of the adhesive polymer with the crystalline polymer can be effectively increased. preferable.

Preferable examples of the (meth) acrylic monomer having a phenyl group in the molecule include phenoxyethyl acrylate and phenoxypropyl acrylate. All of these have a phenoxy group as a phenyl group. Examples of the (meth) acrylic monomer having a crosslinkable functional group in the molecule include unsaturated acids such as (meth) acrylic acid and epoxy group-containing (meth) acrylic monomers such as glycidyl (meth) acrylate. Is included. Each of these has a thermally crosslinkable functional group in the molecule. Further, a photo-crosslinking property may be imparted to the adhesive polymer by using a (meth) acrylic monomer having an unsaturated double bond and a photocrosslinkable functional group in the molecule such as acryloylbenzophenone. Alternatively, a heat-crosslinkable functional group and a photocrosslinkable functional group may be introduced into the adhesive polymer to impart the heat-crosslinkability and the photocrosslinkability.

In addition to the above-mentioned monomers, it is more desirable to further include (D) an acrylic monomer containing an alkyl group having 4 to 10 carbon atoms. However, it is necessary that this acrylic monomer does not have (a) a hydroxyl group, (b) a phenyl group, and (c) a crosslinkable functional group. An example of such an acrylic monomer is acrylic acid n.
-Butyl, isobutyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate and the like.

The crystalline polymer used in the present invention is usually 4
It has a melting point of 0 to 60 ° C and is crystallized at room temperature. In such a case, the adhesive composition has a high cohesive force although it hardly shows tackiness or tack at room temperature. However, these crystalline polymers melt when heated to a temperature higher than the melting point, and become extremely compatible with the acrylic pressure-sensitive adhesive polymer, so that they function as a plasticizer for the adhesive composition. As a result, the adhesive composition loses its cohesive strength, but on the other hand has increased tack. That is, this adhesive composition becomes a heat-activatable adhesive, and when it is heat-activated as described above, it becomes wet and can be bonded to an adherend. Further, when the adhesive composition that has been heated once is cooled to room temperature again, the crystalline polymer is recrystallized. Then, the adhesive composition loses tack, but increases cohesive force on the other hand, and the adherend can be bonded with a very high adhesive force.

The bonding of the adhesive composition to the adherend is reversible. Therefore, this adhesive composition also has the property of being easily removable by heating, and can be easily removed from the adherend by heating without damaging the adherend. This is because when the adhesive composition is heated, the crystalline polymer loses its cohesive force and the adhesive force decreases as described above.

The compatibility between the acrylic pressure-sensitive adhesive polymer and the crystalline polymer can be generally evaluated by visually observing a change in transparency or a decrease in haze (haze) of the adhesive composition or by observing with a polarizing microscope. Therefore, the amount of heat required for heat activation and re-peeling of the adhesive composition can be easily grasped. In particular, haze can be accurately measured by a color difference meter and is useful for quality control of the adhesive composition of the present invention.
In general, in order to say that the acrylic adhesive polymer and the crystalline polymer are compatible with each other, the adhesive composition of the present invention has a relatively low haze, preferably 3% or less, and more preferably It has a haze of 2% or less.

According to the present invention, as the above-mentioned crystalline polymer, crystalline polycarbonate and / or 1,9 is used.
-Nonanediol-containing crystalline polyester polyols are commonly used. These crystalline polycarbonates and 1,
This is because the 9-nonanediol-containing crystalline polyester polyol has relatively excellent weather resistance such as heat resistance and hydrolysis resistance as compared with the above-mentioned polycaprolactone. Such a crystalline polycarbonate or a crystalline polyester polyol containing 1,9-nonanediol can reversibly provide high cohesive force for a long time even in an adhesive composition which is heated or brought into contact with moisture. . Therefore,
The adhesive composition of the present invention is excellent in environmental stability, has high reliability over a long period of time, can provide a desired adhesive force by heat activation, and can exhibit heat repeelability easily.

Crystalline polycarbonate is particularly excellent in hydrolysis resistance, which makes it very effective for adhesive compositions used under high humidity. An example of such a crystalline polycarbonate includes crystalline polycarbonate diol. Crystalline polycarbonate diol is a reaction product of a carbonate compound such as ethylene carbonate and a diol compound such as 1,6-hexanediol. A preferred 1,9-nonanediol-containing crystalline polyester diol is a 1,9-nonanediol-containing crystalline polyester diol having high crystallinity. If necessary, the crystalline polycarbonate diol or crystalline polyester diol may be polyurethane-ized with diisocyanate to control the molecular weight or enhance the compatibility with the acrylic adhesive polymer.

The tack of the adhesive composition at room temperature can be controlled by adjusting the amount of the crystalline polymer added. For example, when this adhesive composition contains 30% by weight or more of a crystalline polymer, the tack at room temperature should be relatively low like the acrylic adhesive polymer derived from a monomer component having a phenoxy group. This enables effective positioning of the adherend. Further, the adhesive composition contains 20% by weight or less of a crystalline polymer and an acrylic tacky polymer having a relatively low Tg (about -15 ° C or less) (for example, 2-ethylhexyl acrylate and / or butyl acrylate as a main component). And a polymer of the above-mentioned monomer component), a pressure-sensitive adhesive composition which has a high tack at normal temperature and which is easily removable by heating.

The adhesive composition of the present invention can be effectively used by processing it into a tape or sheet by the method described below, for example. However, the method of using the present invention is
The method is not limited to this, and may be used by a method well known and commonly used by those skilled in the art.

First, an acrylic adhesive polymer and a crystalline polymer are uniformly mixed in a solvent at a predetermined compounding ratio to prepare an adhesive composition precursor. Here, for mixing, a conventional device such as a homomixer or a planetary mixer can be used. Further, as the solvent, for example, ethyl acetate, toluene, methyl ethyl ketone, acetone and a mixture thereof can be used. Further, the above-mentioned crosslinking agent may be added if necessary.

Next, a predetermined amount of this adhesive composition precursor is applied onto the surface of the base material. Here, for coating, a conventional coating means such as a nicoater, roll coater, die coater or bar coater can be used. The substrate is generally a film made of metal, paper or plastic. Such film-like substrate (adherend)
Usually has a thickness of 5 to 500 μm, preferably 10 to 300 μm. Further, the film-like adherend has transparency or reflectivity with respect to visible light or ultraviolet light,
The decorative sheet or the marking film may have retroreflectivity, or may be colored or decorated by printing or the like to form a decorative sheet or a marking film.

Thereafter, the adhesive composition precursor is placed in an oven together with the above-mentioned substrate, and the adhesive composition precursor is heated and dried at a predetermined temperature for a predetermined time to remove the solvent and have a predetermined thickness. A tape-shaped or sheet-shaped adhesive composition (hereinafter referred to as "film adhesive") is prepared.

If desired, the film adhesive may be covered with a liner to protect it. Liners are commonly made from paper or plastic. In the case of a paper liner, a polyethylene or silicone release layer is usually provided on the surface thereof. When a silicone release layer is used, an undercoat such as clay coat or polyethylene coat is generally interposed between the substrate and the release layer. The preferred plastic is polyethylene terephthalate (PET) from the standpoint of availability. Also in the case of plastic, it is desirable that the liner base material is similarly subjected to a peeling treatment. Alternatively, the surface of the plastic liner may be provided with fine irregularities, and may be adhered to the film adhesive. In such a case, a shape corresponding to the unevenness is formed on the surface of the film adhesive by transfer. The irregularities may be arranged in a regular or irregular pattern. Further, unless the objects and effects of the present invention are impaired, glass beads are placed in the recesses of the liner,
Glass beads may be scattered on the surface of the film adhesive during the transfer.

Next, the film adhesive is brought into close contact with the adherend. Thereafter, the film adhesive is heated to a temperature equal to or higher than the melting point of the crystalline polymer as described above,
It is activated by heat and adheres to the adherend.

If desired, the film adhesive can be heated to a temperature above the melting point of the crystalline polymer,
It can be peeled off from the adherend. Examples of adherends are metallic materials such as aluminum, stainless steel, copper or zinc steel sheets, organic materials such as polyimide, acrylic resin, polyurethane, melamine resin, epoxy resin or vinyl chloride resin, or inorganic oxidation such as ceramic or glass. It is an article made of a physical material or an article whose surface is made of such a material.

Although the present invention has been described according to the preferred embodiments, the present invention is not limited to these. A tackifier may be used in combination with the tackifying polymer as long as the object and effects of the present invention are not impaired. In addition, an acrylic polymer compatible with the above-mentioned crystalline polymer may be added.
An example of such an acrylic polymer is a polymer of the following mixture or mixed monomer. (I) Alkyl (meth) acrylate mixture consisting of 2-ethylhexyl methacrylate, butyl methacrylate and methyl acrylate (ii) Mixed monomer containing acrylic acid and / or methacrylic acid The acrylic polymer can be a non-adhesive polymer. At that time, it is desirable that the adhesive composition of the present invention contains a crosslinking component that reacts with the carboxyl group of the (meth) acrylic acid.

Further, the adhesive composition of the present invention may contain various additives in addition to the above tackifier and acrylic polymer. Such additives include, for example:
Plasticizers, viscosity modifiers, defoamers, leveling agents, UV absorbers, antioxidants, pigments, antifungal agents, elastic microspheres made of sticky polymers or non-sticky rubber polymers, and catalysts that accelerate the crosslinking reaction. is there.

[0033]

EXAMPLES The present invention will be described below with reference to examples. However, it goes without saying that the present invention is not limited to these examples.

Examples 1 to 4 and Comparative Example 1 1. Preparation of Film Adhesive In this example, the acrylic adhesive polymer, the crystalline polymer, and the cross-linking agent are listed in Table 1 in an ethyl acetate / toluene mixed solvent (ethyl acetate: toluene = 50: 50 (mass ratio)). The adhesive composition precursor was prepared by mixing in the weight ratios shown. Next, a predetermined amount of this adhesive composition precursor was applied to a release-treated liner made of polyethylene terephthalate (PET). Then, the adhesive composition precursor was put into an oven together with the above liner, and was heated and dried at 100 ° C. for 5 minutes to remove the ethyl acetate / toluene mixed solvent to obtain a film adhesive having a thickness of 25 μm.

2. Evaluation of Film Adhesive Next, after removing the liner from the above film adhesive, the film adhesive was heated to about 2 kg /
While applying a pressure of cm ² at 80 ° C., it was attached to a polyimide film having a thickness of 25 μm. Further, while applying a pressure of 10 kg / cm ² at 100 ° C. for 60 seconds on the exposed surface of this film adhesive, a glass epoxy plate (adherend) was thermocompression bonded to obtain a sample. After leaving this sample for 24 hours at 25 ° C, the film adhesive was peeled off at 180 ° at 25 ° C from the adherend at a speed of 50 mm / min, and the initial 180 ° peel adhesive strength (initial adhesive strength) at that time Was measured.

The 180 ° peel adhesive strength at 25 ° C. was similarly measured for the sample after aging under the following conditions. (1) Put the sample in the oven and leave at 100 ° C for 100 hours. (2) Put the sample in the oven at 85 ° C and relative humidity (R
H) Leave at 85% for 72 hours

Further, the 180 ° peel adhesive strength at the initial stage and after aging was also measured for a sample using a stainless steel plate SUS304 instead of the glass epoxy plate.

Table 1 shows the initial adhesive strength and 1 after aging.
Shows 80 ° peel adhesion. In addition, in parentheses in Table 1, the increase / decrease rate of the 180 ° peel adhesive strength after aging with respect to the initial adhesive strength is shown in percentage.

As is clear from the results shown in Table 1, Example 1
In the film adhesives of the present invention Nos. 4 to 4, the 180 ° peel adhesive force is maintained before and after aging, or is further enhanced after aging, and it can be seen that the film adhesive has excellent aging resistance. Also, the absolute value of the 180 ° peel adhesion is relatively high. On the other hand, the film adhesive of Comparative Example 1 has a high initial adhesive strength equivalent to that of Examples 1 to 4, but the 180 ° peel adhesive strength is reduced after aging, and thus the aging resistance is low. It turns out to be inferior.
Therefore, it can be seen that the film adhesive using the predetermined crystalline polymer according to the present invention has excellent aging resistance.

[0040]

[Table 1]

Note: ・ PSA-1: phenoxyethyl acrylate / 2-hydroxy-3-phenoxypropyl acrylate / butyl acrylate / acrylic acid (weight ratio 30:15:50:
Copolymer of 5). -CD220: crystalline polycarbonate diol (PLACCEL CD220 manufactured by Daicel Chemical Industries, weight average molecular weight (Mw) = 7,
000). CD220-PUR2: A crystalline polycarbonate-based polyurethane (Mw = 35,000) obtained by reacting the above PLACCEL CD220 with isophorone diisocyanate at a molar ratio of 5: 4. -Pol-PUR1: A crystalline polyester-based polyurethane (Mw = 49,000) obtained by reacting a crystalline polyester polyol (Kuraray polyol N-2010, manufactured by Kuraray, Mw = 8,000) with isophorone diisocyanate at a molar ratio of 6: 5. -Pol-PUR2: A mixed crystalline polyester polyol and isophorone diisocyanate obtained by further adding a crystalline polyester polyol containing 1,9-nonanediol (Kuraray polyol O-2010, Mw = 7,000) containing 1,9-nonanediol to the above Kuraray polyol N-2010. Crystalline polyester-based polyurethane (Mw = 43,000) obtained by reacting
0). -PCL-H1P: crystalline polycaprolactone (PLACCEL H1P manufactured by Daicel Chemical Industries, Mw = 25,000).

Examples 5-10 and Comparative Example 2 1. Preparation of Adhesive Composition In this example, a predetermined amount of the adhesive composition precursor containing the compounds shown in Table 2 in the stated weight ratio was applied to a polyurethane film having a thickness of 35 μm to have a thickness of 30 μm. The same procedure as in the above Examples and Comparative Examples was carried out except that a film adhesive was prepared.

2. Evaluation of film adhesive Next, the above film adhesive was attached to a stainless steel plate (SUS304) as an adherend, and a 2 kg roller was placed at 25 ° C.
Then, the film adhesive was pressure-bonded to the stainless steel plate to make a sample. Next, this sample was allowed to stand at 25 ° C. for 24 hours, then the film adhesive was peeled by 180 ° at a speed of 300 mm / min, and the initial 180 ° peel adhesive strength (initial adhesive strength) at that time was measured.

Table 2 shows the initial adhesive strength of each film adhesive of this example. According to the results shown in Table 2, Examples 5-8
It can be seen that when the blending amount of the crystalline polymer is relatively small like the film adhesive of No. 3, the initial adhesive strength is high due to high tack at room temperature. On the contrary, when the amount of the crystalline polymer blended is relatively large like the film adhesives of Examples 9 and 10, the low initial tack is low due to low tack at room temperature, which is advantageous for alignment. I understand.

Next, the ease of heat re-peeling of the film adhesive was evaluated as follows. First, the film adhesive of this example was attached to a stainless steel plate (SUS304) as an adherend, and then a pressure of 5 kg / cm ² was applied at 80 ° C. for 1 minute,
A sample was prepared by pressing the film adhesive onto a stainless steel plate. After leaving this sample at 25 ° C. for 24 hours,
The film adhesive was peeled by 180 ° at a speed of mm / min, and the 180 ° peel adhesive force at that time was measured.

This sample was placed in an oven at 80 ° C.
After heating for 3 minutes, the sample was taken out of the oven and left at 25 ° C. for 6 minutes. Thereafter, the film adhesive was peeled from the adherend by 180 ° at a speed of 300 mm / min, and the 180 ° peel adhesive strength at that time was measured.

Table 2 shows the 180 ° peel adhesive strength of the above two types. From the results of Table 2, it can be seen that the film adhesives of Examples 5 to 10 tend to increase the adhesive force by thermocompression bonding compared to the initial stage. In particular, this tendency is remarkable when the crystalline polymer is used in a large amount like the film adhesives of Examples 9 and 10. Further, it can be seen that the film adhesive of this example according to the present invention maintains a relatively low adhesive force even after 6 minutes after heating, and is easily peeled off again. On the other hand, the film adhesive of Comparative Example 2 containing no crystalline polymer maintained a relatively high adhesive force even 6 minutes after heating, and the above-mentioned ease of heat re-peeling was not observed.

[0048]

[Table 2]

Note: AST-8142: Butyl acrylate adhesive polymer (Nippon Shokubai, Aroset 8142). -O-2010: 1,9-nonanediol-containing crystalline polyester polyol (Kuraray, Kuraray polyol O-2010, Mw
= 7,000). CD220-PUR1: A crystalline polycarbonate polyurethane (Mw = 15,000) obtained by reacting the above PLACCEL CD220 with isophorone diisocyanate at a molar ratio of 2: 1. Pol-PUR3: A crystalline polyester polyurethane (Mw = 15,000) obtained by reacting the above Kuraray polyol O-2010 with isophorone diisocyanate at a molar ratio of 2: 1.

[0050]

INDUSTRIAL APPLICABILITY The adhesive composition of the present invention can maintain or improve a relatively high adhesive force for a long period of time, and thus can be used as a heat-removable heat-activatable adhesive having improved reliability.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroaki Sakamoto             Sumitomo 3-8-8 Minami-Hashimoto, Sagamihara City, Kanagawa Prefecture             Within 3M Co., Ltd. F-term (reference) 4J040 CA081 DB051 DF001 DF031                       DF041 DF051 DF061 DF071                       DF081 ED002 EF001 EK031                       EL022 GA05 JA09 JB01                       JB09 LA06 LA07 PA42

Claims (3)

[Claims] 1. An adhesive composition comprising a tacky polymer and at least one crystalline polymer selected from the group consisting of crystalline polycarbonate and crystalline polyester polyol containing 1,9-nonanediol. 2. The adhesive composition according to claim 1, wherein the crystalline polycarbonate contains a crystalline polycarbonate diol. 3. The adhesive composition according to claim 1, wherein the 1,9-nonanediol-containing crystalline polyester polyol contains a 1,9-nonanediol-containing crystalline polyester diol.