JP2000186265A - Adhesive composition and adhesive sheet prepared therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition excellent in initial adhesive power and in releasability from a release liner by compounding a polyester polymer formed by using an aliphatic polycarbonate diol as an essential polyol with an acrylic polymer which does not substantially contain an acid component and has a specified glass transition point, each in a specified amount. SOLUTION: This composition comprises 50-95 wt.% polyester polymer which is formed by using an aliphatic polycarbonate diol as an essential polyol and preferably has a wt. average mol.wt. of 10,000 or higher (e.g. a polyester polymer formed from sebacic acid and a polycarbonate diol obtained by reacting butanediol with ethylene carbonate) and 50-5 wt.% acrylic polymer which does not substantially contain an acid component and has a glass transition point lower than -10 deg.C. The composition does not cause the problem with the corrosion or malfunction of an appliance due to an acid component or a siloxane gas in the field of electronic appliances and can be used in applications where instant adhesion is needed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition containing a polyester polymer and an acrylic polymer, and pressure-sensitive adhesive sheets in the form of a sheet or tape. .

[0002]

2. Description of the Related Art An acrylic pressure-sensitive adhesive is mainly composed of an acrylic copolymer obtained by copolymerizing an alkyl (meth) acrylate as a main monomer and adding an acid component such as acrylic acid thereto. It is widely used in various fields as having excellent adhesive properties such as high adhesive strength. However, since the acrylic pressure-sensitive adhesive contains the above-mentioned acid component, when it is used as an adhesive material for an electronic device or the like, if the device is directly touched, the device or the like may be corroded.

[0003] Adhesive sheets are bonded with a release liner from the viewpoint of protection of the adhesive surface and handleability. In the case of an acrylic adhesive, the surface is made of silicone to obtain good release properties. Uses a treated release liner. However, in this type of release liner, silicone migrates to the adhesive surface and siloxane gas is generated inside the electronic device, which may cause corrosion and malfunction of the electronic device.

[0004] On the other hand, recently, carbon-
Pressure-sensitive adhesives containing a polyether-based polymer having a bond as a main component have been proposed. Such polyester-based pressure-sensitive adhesives do not have to worry about corrosion of electronic devices due to acid components such as acrylic-based pressure-sensitive adhesives, and have been treated with silicone such as polyolefin-based film to protect the adhesive surface. Even when a release liner is used, sufficient release properties can be obtained, so there is no need to worry about the migration of silicone to the adhesive surface. There is no danger of malfunction.

[0005]

As described above, the polyester-based pressure-sensitive adhesive has an advantage over the acrylic-based pressure-sensitive adhesive in that it does not cause corrosion or malfunction of electronic equipment due to generation of an acid component or siloxane gas. Despite having the disadvantage of poor initial tackiness, it is used for applications requiring instant bonding, such as high-speed continuous bonding and applications where stress is applied immediately after bonding. I couldn't.

In view of such circumstances, the present invention avoids corrosion and malfunction of electronic devices and the like due to generation of an acid component and siloxane gas, and improves the pressure-sensitive adhesive composition with improved initial tackiness and its pressure-sensitive adhesive sheet. The purpose is to provide products.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and have found that a specific acrylic polymer as well as a polyether polymer having a carbonate bond in the molecule. By using in combination,
It is possible to avoid problems such as corrosion and malfunction of electronic devices due to the generation of acid components and siloxane gas, and to exhibit good adhesive properties, especially adhesive compositions with improved initial adhesiveness and their adhesive sheets. Knowing that it can be obtained, the present invention has been completed.

That is, the present invention comprises: A) 50 to 95% by weight of a polyester polymer containing an aliphatic polycarbonate as an essential polyol component, and B) substantially containing an acid component. A pressure-sensitive adhesive composition comprising 50 to 5% by weight of an acrylic polymer having a glass transition temperature of not more than -10 ° C (claim 1), especially the weight-average molecular weight of the polyester polymer of component A Is 10,000 or more according to the pressure-sensitive adhesive composition having the above constitution (Claim 2).
Further, the present invention is characterized in that the support has a layer comprising the pressure-sensitive adhesive composition having the above constitution on one or both sides thereof.
The present invention relates to adhesive sheets in the shape of a sheet or tape (claim 3).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester polymer of the component A in the present invention is a polyester comprising an aliphatic polycarbonate component as an essential polyol component, that is, an aliphatic polycarbonate component. A polyester comprising a polyol component containing 50% by weight or more, preferably 60% by weight or more, and a polybasic acid component, having a weight average molecular weight of 10,000 or more and usually up to 200,000, preferably 20,000 to 150,000,
More preferably, those having 30,000 to 120,000 are used. If the molecular weight of this polyester polymer is too low,
Good results are unlikely to be obtained for adhesive properties such as adhesive strength.

[0010] Aliphatic polycarbonates are:
The following formula: (Wherein R is an aliphatic hydrocarbon group having 2 to 20 carbon atoms), is a diol having a repeating unit represented by the formula:
For example, it is obtained by reacting a diol component such as butanediol and a carbonate compound such as ethylene carbonate. As a commercially available product, "PLACCEL CD220P" manufactured by Daicel Chemical Industries, Ltd.
L "," CD210PL "," CD205PL ",
"Same CD220" and "Same CD210".

As the polyol component, in addition to the above-mentioned aliphatic polycarbonate diol, ethylene glycol
And propylene glycol, butanediol, hexanediol, octanediol, decanediol, octadecandiol, and other linear diol components. The polybasic acid component to be reacted with the polyol component has an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms as a molecular skeleton, and the hydrocarbon group has a linear structure. Or may be branched. Specifically, malonic acid, succinic acid, methyl succinic acid, adipic acid, sebacic acid, 1,12-dodecandioic acid, 1,14-
Tetradecandioic acid, n-hexyl adipic acid, tetrahydrophthalic acid, endmethylene tetrahydrophthalic acid, and the like, and derivatives such as acid anhydrides and esters thereof are used.

The acrylic polymer of the component B in the present invention is used for improving the initial adhesiveness of the release-liner without impairing the excellent adhesive properties based on the polyester polymer of the component A and the release property of the release liner. And has 4 carbon atoms
A polymer having a main monomer of an alkyl (meth) acrylate having an alkyl group of from 1 to 14 and containing substantially no acid component, and having a glass transition temperature of -10 ° C or lower, preferably -15 ° C. ℃ or less (usually up to about -90 ℃)
Is used. Here, substantially not containing an acid component means that an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, or maleic acid is not used as a monomer component. It is designed to prevent corrosion. Further, by setting the glass transition temperature to -10 ° C or lower, favorable results can be obtained for the above-mentioned original purpose, that is, the improvement of the initial adhesiveness, together with the adhesive properties such as the adhesive strength.

The alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms as a main monomer includes butyl, isobutyl, isoamyl, hexyl, heptyl, 2-ethylhexyl and isooctyl. It is an alkyl ester of (meth) acrylic acid having an alkyl group such as a group, an isononyl group, a lauryl group, or an isomyristyl group. Together with this main monomer, monomers other than unsaturated carboxylic acids, such as vinyl acetate, styrene, 2-hydroxyethyl (meth) acrylate, and (meth) acrylonitrile, are commonly used in acrylic pressure-sensitive adhesives. Some well-known vinyl monomers can be used in combination. These other monomers are desirably used in a range where the above main monomer accounts for 50% by weight or more.

The pressure-sensitive adhesive composition of the present invention is usually prepared by separately synthesizing the polyester polymer of the component A and the acrylic polymer of the component B and then mixing the two in bulk or solution. Can be prepared. However, depending on the case, the polymer may be prepared by any method when one polymer is polymerized with the other, or may be prepared by polymerizing both at the same time.

In these preparation methods, the polyester polymer of the component A and the acrylic polymer of the component B are contained in an amount of 50 to 50% of the total amount of both.
95% by weight, preferably 60 to 90% by weight, and 50 to 5% by weight, preferably 4 to 5% by weight of the acrylic polymer of the B component.
It is preferably from 0 to 10% by weight. If the content of the polyester polymer of the component A exceeds 95% by weight, that is, if the content of the acrylic polymer of the component B is less than 5% by weight, the effect of improving the initial tackiness cannot be sufficiently obtained, and the polyester weight of the component A If the combined amount is less than 50% by weight, that is, if the amount of the acrylic polymer as the component B exceeds 50% by weight, the adhesive properties and the releasability of the release liner are reduced.

The pressure-sensitive adhesive composition of the present invention is mainly composed of the polyester polymer of the above-mentioned component A and the acrylic polymer of the above-mentioned component B. Usually, this is subjected to a crosslinking treatment to give an adhesive. The characteristics can be excellent. In the crosslinking treatment, a polyisocyanate compound, an epoxy compound, an aziridine compound, or the like may be added as a crosslinking agent, and this may be reacted with a functional group such as a hydroxyl group contained in the above both polymers. In addition, the pressure-sensitive adhesive composition of the present invention, in addition to the above crosslinking agent, if necessary, a tackifier, an inorganic or organic filler, metal powder, powders such as pigments, particulates, foils and the like Various known additives can be contained.

The pressure-sensitive adhesive sheets of the present invention can be prepared by using various plastic films such as polyester film, paper, non-woven fabric, foam, metal foil, a laminate thereof, etc. as a support, on one or both sides of the support. A layer made of the above-mentioned pressure-sensitive adhesive composition is provided on one side to a thickness of usually 10 to 150 μm, and is in the form of a sheet or a tape,
A release liner is attached to the pressure-sensitive adhesive surface, that is, the surface of the layer composed of the pressure-sensitive adhesive composition, from the viewpoint of surface protection and handleability.

As the release liner, a release liner that has not been subjected to silicone treatment can be used, and a polyolefin-based film is particularly preferably used. As the polyolefin-based film, a film made of polyethylene, polypropylene, polymethylpentene, an ethylene-propylene copolymer or a mixture thereof, a film whose surface is processed with the same polyolefin as described above, and the like can be used.

The thus prepared adhesive sheets of the present invention exhibit excellent adhesive properties and excellent initial adhesiveness, so that they can be used not only for ordinary adhesive applications but also for instantaneous adhesion. For example, it can be sufficiently used for high-speed continuous bonding work and applications where stress is applied immediately after bonding. Also, since the acrylic polymer used together with the polyester polymer does not substantially contain an acidic group, there is no adverse effect due to the acidic group, and further, the release liner to be bonded to the adhesive surface has not been subjected to silicone treatment. Even with a liner, good releasability can be obtained, so there is no need to worry about migration of silicone to the adhesive surface, and therefore it is also suitable for electronic equipment applications that do not like the presence of acid components and silicone. ,
Can be used without any problems.

[0020]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited by the following examples. In the following, “parts” means “parts by weight”.

Example 1 In a four-neck separable flask equipped with a stirrer, a thermometer, and a water separation tube, a liquid polycarbonate (trade name "PLACCEL CD" manufactured by Daicel Chemical Industries, Ltd.) was placed.
220PL ", hydroxyl value: 56.1 KOHmg / g] 25
0 parts, 26.6 parts of sebacic acid, 0.1 part of titanium tetraisopropoxide (hereinafter referred to as TPT) as a catalyst, and stirring was started in the presence of a small amount of toluene and xylene as a solvent for discharging reaction water. The temperature was raised to 180 ° C. while maintaining the temperature. After a while, effluent separation of water was observed, and the reaction began to proceed. The reaction was continued for about 25 hours to obtain a solution of a polyester polymer having a weight average molecular weight of 38,000.

Separately, toluene 100 was placed in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirring device.
Parts as solvent, 50 parts of isononyl acrylate, 38 parts of ethyl acrylate, 10 parts of methyl methacrylate, 2 parts of 2-hydroxyethyl acrylate, 0.1 part of benzoyl peroxide.
By charging 2 parts and polymerizing in a nitrogen stream, a solution of an acrylic polymer having a glass transition temperature of -41 ° C and a weight average molecular weight of 450,000 was obtained.

Next, the solution of the polyester polymer and the solution of the acrylic polymer were mixed so that 90 parts of the polyester polymer was 10 parts of the acrylic polymer.
3 parts (solid content) of a tolylene diisocyanate adduct of trimethylolpropane (trade name: "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) was added thereto as a crosslinking agent, and the mixture was mixed. Solution of the agent composition. This adhesive composition solution was applied to an applicator to a thickness of 38 μm.
m polyethylene terephthalate film
After drying at 120 ° C. for 3 minutes, a layer of the pressure-sensitive adhesive composition having a thickness of 30 μm was formed. A 150 μm-thick polyethylene film was attached to the adhesive surface as a release liner to produce an adhesive tape.

Example 2 The solution of the polyester polymer and the solution of the acrylic polymer obtained in Example 1 were mixed so that 80 parts of the polyester polymer and 20 parts of the acrylic polymer were mixed. Further, 3 parts (solid content) of a tolylene diisocyanate adduct of trimethylolpropane (trade name: “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. . Using a solution of this pressure-sensitive adhesive composition,
Thereafter, an adhesive tape was produced in the same manner as in Example 1.

Example 3 A four-necked separable flask equipped with a stirrer, a thermometer and a water separation tube was charged with a liquid polycarbonate [trade name "PLACCEL CD" manufactured by Daicel Chemical Industries, Ltd.]
220PL ", hydroxyl value: 56.1 KOHmg / g] 25
0 parts, 24.6 parts of azelaic acid, and 0.1 part of TPT as a catalyst, and in the presence of a small amount of toluene and xylene as a solvent for discharging reaction water, the temperature was raised to 180 ° C. while stirring was started. Hold at temperature. After a while, effluent separation of water was observed, and the reaction began to proceed. The reaction was continued for about 27 hours to obtain a solution of a polyester polymer having a weight average molecular weight of 41,000.

Separately, toluene 100 was added to a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirring device.
Parts as a solvent, n-butyl acrylate 70 parts, ethyl acrylate 27 parts, 2-hydroxyethyl acrylate 3
Parts, 0.2 parts of benzoyl peroxide was charged and polymerized in a nitrogen stream to obtain a glass transition temperature of -46 ° C.
A solution of an acrylic polymer having a weight average molecular weight of 380,000 was obtained.

Next, the solution of the polyester polymer and the solution of the acrylic polymer were mixed such that 30 parts of the acrylic polymer per 70 parts of the polyester polymer was used.
3 parts (solid content) of a tolylene diisocyanate adduct of trimethylolpropane (trade name: "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) was added thereto as a crosslinking agent, and the mixture was mixed. Solution of the agent composition. Using this solution of the pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape was prepared in the same manner as in Example 1.

Comparative Example 1 The solution of the polyester polymer and the solution of the acrylic polymer obtained in Example 1 were mixed so that 60 parts of the acrylic polymer per 40 parts of the polyester polymer were mixed. Further, 3 parts (solid content) of a tolylene diisocyanate adduct of trimethylolpropane (trade name: “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. . Using a solution of this pressure-sensitive adhesive composition,
Thereafter, an adhesive tape was produced in the same manner as in Example 1.

Comparative Example 2 A solution of the polyester polymer obtained in Example 1 was added to 100 parts (solid content) of the polyester polymer, and a hexamethylene diisocyanate adduct of trimethylolpropane (Japan) was used as a crosslinking agent. 3 parts (solid content) of polyurethane (trade name "Coronate L") were added and mixed to obtain a solution of the pressure-sensitive adhesive composition. Using a solution of this pressure-sensitive adhesive composition,
Thereafter, an adhesive tape was produced in the same manner as in Example 1.

Comparative Example 3 A solution of the acrylic polymer obtained in Example 1 was added to 100 parts (solid content) of the acrylic polymer per 100 parts of the acrylic polymer (solid content) as a crosslinking agent with hexamethylene diisocyanate adduct of trimethylolpropane (Japan). 2 parts (solid content) of polyurethane (trade name "Coronate L") were added and mixed to obtain a solution of the pressure-sensitive adhesive composition. Using this solution of the pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape was prepared in the same manner as in Example 1.

With respect to each of the adhesive tapes of Examples 1 to 3 and Comparative Examples 1 to 3, the initial adhesive strength, adhesive strength, and peel strength of the release liner were measured by the following methods. The results of these measurements were as shown in Table 1.

<Initial Adhesive Strength> Adhesive tape was 20 mm × 10
The sheet was cut into a size of 0 mm, peeled off the release liner in an atmosphere of 23 ° C. and 65% RH, and pressed on an aluminum plate as an adherend under the condition of one reciprocation of 2 kg roller. After 10 seconds, the 180 ° peel adhesive strength (Kg / 20 mm width) was measured under the condition of a peel rate of 300 mm / min, which was defined as the initial adhesive strength.

<Adhesive Force> The 180 ° peel adhesive force (Kg / 20 mm width) was measured in the same manner as in the case of the initial adhesive force, except that the adhesive force was measured 30 minutes after the adhesion to the aluminum plate. And

<Peeling force of peeling liner>
After cutting to a size of 100 mm x 100 mm, the polyethylene terephthalate film side as a support is fixed to a stainless steel plate with a double-sided tape, and then peeled off from the adhesive tape in an atmosphere of 23 ° C and 65% RH. Liner pulling speed 300mm
The peeling force (g / 50 mm width) was measured when the film was peeled off under the condition of 1 / min.

[0035]

As is clear from the results in Table 1 above, each of the pressure-sensitive adhesive tapes of Examples 1 to 3 of the present invention is excellent in adhesive strength and peelability of the release liner, and also excellent in initial tackiness. You can see that there is. On the other hand, the adhesive tape of Comparative Example 1 in which the amount of the acrylic polymer used was too large had the same adhesive properties as the adhesive tape of Comparative Example 3 in which the acrylic polymer was used alone. The adhesive tape of Comparative Example 2, which was inferior in the peelability of the release liner and the polyester-based polymer alone,
Poor initial tackiness.

[0037]

As described above, the present invention provides a polyester-based polymer containing an aliphatic polycarbonate diol as an essential polyol component and a glass transition temperature substantially free of an acid component. The use of a specific amount of an acrylic polymer having a temperature of −10 ° C. or less makes it possible to use a release liner that has not been subjected to silicone treatment such as a polyolefin-based film, and has excellent adhesive strength and initial adhesive strength. For example, in applications where electronic components are not used, problems such as corrosion or malfunction of devices due to the generation of acid components or siloxane gas do not occur, and applications that require instantaneous adhesion, such as It is possible to provide a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet which can be sufficiently used in a high-speed continuous bonding operation or an application in which stress is applied immediately after bonding.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Tokunaga 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Hiroshi Yamamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Within Nitto Denko Corporation (72) Inventor Naoyuki Nishiyama 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4J004 AA02 AA10 AA15 AB01 CA02 CA06 CA08 CB01 CB02 CB04 CC02 CC03 DA02 DB02 EA05 FA05 4J040 DF041 DF042 DF051 DF052 ED051 JA09 JB09 LA01 LA02 LA06 LA11 NA19

Claims (3)

[Claims] 1. A) Polyester-based polymer 5 containing aliphatic polycarbonate-diol as an essential polyol component
0 to 95% by weight, and B) an acrylic polymer having substantially no acid component and having a glass transition temperature of -10 ° C or lower.
An adhesive composition comprising 5% by weight. 2. The pressure-sensitive adhesive composition according to claim 1, wherein the weight average molecular weight of the polyester polymer of the component A is 10,000 or more. 3. A pressure-sensitive adhesive sheet having a layer comprising the pressure-sensitive adhesive composition according to claim 1 on one or both sides of a support.