JPH10287858A - Autohesive tacky agent and its tacky member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject tacky agent, having a low adhesive strength to adherends, excellent in autohesive strength and holding power between mutual tacky layers and suitable for binding, fixing for carrying, protection, etc., by including a specific base polymer, a tackifier and a polyfunctional isocyanate- based compound as essential components therein. SOLUTION: This tacky agent is obtained by including (A) 100 pts.wt. base polymer comprising a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound (e.g. a styrene-isoprene-styrene block copolymer), (B) preferably 1-150 pts.wt., especially 3-120 pts.wt. tackifier and (C) preferably 0.2-20 pts.wt., especially 0.3-18 pts.wt. polyfunctional isocyanate-based compound having >=2 isocyanate groups (e.g. tolylene diisocyanate) as essential components and preferably further including (D) <=50 pts.wt. rubber-based polymer other than the base polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a self-adhesive film having a low adhesive strength to an adherend and an excellent self-adhesive force between the adhesive layers, particularly excellent holding power, and suitable for use in binding, fixing for transport and protection, etc. Adhesive,
And an adhesive member using the same.

[0002]

BACKGROUND OF THE INVENTION Adhesives used for binding fruits and vegetables and for attracting them during cultivation have the characteristic that they have low adhesive strength to adherends such as fruits and vegetables and that the adhesive layers adhere strongly to each other and exhibit high self-adhesive strength. Desired. The group to which the present inventors belong is a monovinyl-substituted aromatic compound / conjugated diene compound block copolymer-based base polymer blended with an alkaline earth metal-based coordination chelate compound, and a self-adhesive adhesive exhibiting the above characteristics. An agent was proposed (Japanese Patent Publication No. Hei 7-113103).

However, the use of self-adhesive pressure-sensitive adhesives has been expanded,
For example, with the expansion of applications for fixing articles for transport purposes, new performance requirements are required, that is, a performance requirement for improving the holding force that does not peel due to misalignment even if stress such as tension or shear acts on the self-adhesive surface for a long time. Occurred.

[0004]

SUMMARY OF THE INVENTION The present invention provides a self-adhesive surface having a low adhesive strength to an adherend and a strong self-adhesive force between adhesive layers, which are required for a self-adhesive adhesive. An object of the present invention is to develop a self-adhesive pressure-sensitive adhesive that exhibits a holding force that does not peel off due to displacement or the like even when a predetermined stress acts for a long time, and that has excellent reliability in a self-adhesive state.

[0005]

The present invention comprises a base polymer comprising a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound, a tackifier, and a polyfunctional isocyanate compound having at least two isocyanate groups. And a pressure-sensitive adhesive member having a pressure-sensitive adhesive layer formed of the self-adhesive pressure-sensitive adhesive on one or both sides of a support substrate.

[0006]

According to the present invention, the molecular weight is increased by the connection of a base polymer or the like via a polyfunctional isocyanate compound, so that the adhesive layer has a weak adhesive strength and the adhesive layers have a strong self-adhesion. In addition to showing the adhesive force, even if a stress such as tension or shear acts on the self-adhesive surface for a long time, the self-adhesive surface is hardly peeled off due to misalignment, etc., and shows a high holding force to maintain the self-adhesive state for a long time. A self-adhesive adhesive excellent in reliability can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The self-adhesive pressure-sensitive adhesive of the present invention comprises a base polymer comprising a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound, a tackifier, and a polyfunctional compound having two or more isocyanate groups. At least an isocyanate compound is used as a component.

The block copolymer used for the base polymer includes, for example, styrene / isoprene / styrene block copolymer, styrene / butadiene / styrene block copolymer or hydrogenated product thereof, styrene / isoprene block copolymer and styrene / styrene block copolymer. As represented by butadiene block copolymer and the like, styrene and α-methylstyrene, a monovinyl-substituted aromatic compound such as vinyltoluene and vinylxylene, and a conjugated diene compound such as 1,3-butadiene and isoprene There are things. The block copolymer can be used alone or in combination of two or more as the base polymer.

Examples of tackifiers for the purpose of improving tackiness include terpene resins, terpene / aromatic resins such as terpene / phenol, phenolic resins, cumarone indene resins, xylene resins, Appropriate resin such as rosin resin, petroleum resin such as aliphatic, aromatic, and aliphatic / aromatic copolymers, and alkyd resin may be used alone or in combination of two or more.

The amount of the tackifier is preferably 1 to 150 parts by weight, more preferably 2 to 150 parts by weight, per 100 parts by weight of the base polymer, in order to prevent an excessive adhesive force from leaving adhesive on the adherend. -130 parts by weight, particularly preferably 3-120 parts by weight.

As the polyfunctional isocyanate compound,
For example, tolylene diisocyanate, xylylene diisocyanate, diphenylmethylene-4,4'-diisocyanate, hexamethylene diisocyanate, diphenylmethane triisocyanate, or polyfunctional isocyanates and polyfunctional alcohols such as trimethylolpropane, glycerin and pentaerythritol. One or more suitable compounds having two or more isocyanate groups in the molecule, such as trimethylolpropane tolylene diisocyanate, which is a reactant, may be used.

The amount of the polyfunctional isocyanate compound to be added is preferably from 100 parts by weight per 100 parts by weight of the base polymer in view of the effect of improving the holding power in self-adhesiveness and the maintainability of self-adhesive strength.
0.2 to 20 parts by weight, preferably 0.3 to 18 parts by weight, is preferred.

The self-adhesive pressure-sensitive adhesive of the present invention may contain one or more rubber-based polymers other than the base polymer, if necessary, for the purpose of improving the adhesive properties. As the rubber-based polymer, for example, an appropriate polymer such as natural rubber, styrene-butadiene rubber, isoprene rubber, polyisobutylene, butyl rubber, NBR, or recycled rubber can be used. The amount of the rubber-based polymer is 5 to 100 parts by weight of the base polymer in view of maintaining self-adhesiveness.
0 parts by weight or less, preferably 40 parts by weight or less, particularly preferably 30 parts by weight or less.

In the present invention, a resin coordination chelate compound comprising an alkaline earth metal can be blended if necessary. Such a resin coordination chelate compound is used for the purpose of improving self-adhesive force, lowering adhesive force to an adherend, improving cutter cutting property of an adhesive layer, and the like, and its compounding amount is based on the fact that self-adhesiveness is not impaired. 100 parts by weight or less, preferably 80 parts by weight or less, particularly preferably 50 parts by weight or less, per 100 parts by weight of the polymer.

Examples of the resin coordination chelate compound include oxides of alkaline earth metals such as magnesium, calcium, strontium and barium, and phenols, rosins and cumarones having a functional group such as a hydroxyl group or a methylol group. An appropriate substance such as a reaction product with a resin can be used. Above all, a coordination chelate compound using an alkylphenol-based resin is preferred from the viewpoint of the above-mentioned blending purpose.

The self-adhesive pressure-sensitive adhesive of the present invention can be prepared by mixing the components in an appropriate manner such as a kneader or a medium via a solvent or a dispersion medium. Upon its preparation, various additives that may be used in pressure-sensitive adhesives such as softeners, plasticizers, antioxidants and ultraviolet absorbers, fillers, pigments, extenders, and the like may be added as necessary. Can be.

The pressure-sensitive adhesive member of the present invention has a pressure-sensitive adhesive layer comprising the above self-adhesive pressure-sensitive adhesive provided on one or both sides of a support substrate. The formation is carried out, for example, by applying a self-adhesive pressure-sensitive adhesive to a support base material by a roll coating method such as a roll coater method or an extrusion melt coating method, a calender roll method, or the like, and a solution of the self-adhesive pressure-sensitive adhesive. It can be carried out by an appropriate method such as a method of coating on a supporting substrate or a method of transferring a layer made of a self-adhesive pressure-sensitive adhesive provided on a separator to the supporting substrate.

The layer composed of the self-adhesive pressure-sensitive adhesive may be coated on one side or both sides of the supporting substrate in a solid coating, or may be partially coated in a streak or dot shape. The coating form is arbitrary. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the use and the like, but is generally 500 μm or less, preferably 1 to 300 μm, particularly 5 to 200 μm.

As the supporting substrate, any suitable material such as paper, cloth, nonwoven fabric, plastic film, metal foil or foam, or a laminate thereof can be used. Washi paper, cotton or souff, rayon or vinylon, polyester or polyamide, polyimide or polypropylene, polyvinyl chloride or polyurethane, acrylic resin or cellophane, polyethylene or natural rubber, synthetic rubber or aluminum, stainless steel or any other suitable material may be used. .

The thickness of the supporting substrate can be appropriately determined according to the use and the like, and may be more than 1 mm, but is generally 500 μm or less, especially 5 to 300 μm. The support substrate may be subjected to a known surface treatment such as a coating treatment with a primer or the like, a corona discharge treatment, a plasma treatment, or the like for the purpose of improving the adhesion to the adhesive layer. In the case of having an adhesive layer on one side, a release coat layer made of an appropriate release agent such as a silicone-based or long-chain alkyl-based is provided on the back surface of the supporting substrate, if necessary, so that the film can be easily unwound. It is also possible to obtain a round adhesive member.

The self-adhesive pressure-sensitive adhesive and the pressure-sensitive adhesive member of the present invention can be used for various bonding applications. However, since the self-adhesive layer is excellent in self-adhesion such as adhesive strength and holding power, it can be used for an adherend. It is preferably used for applications that require low adhesive strength and strong self-adhesion between the adhesive layers, such as bundling fruits and vegetables and fresh flowers, fixing when transporting articles, and protecting the surface of articles. be able to.

[0022]

【Example】

Example 1 80 parts of styrene / isoprene block copolymer (parts by weight, the same applies hereinafter), 20 parts of styrene / isoprene / styrene block copolymer, and styrene / butadiene rubber 30
Part, aliphatic petroleum resin 10 parts, alkylphenol resin / magnesium oxide chelate compound 30 parts, phenolic antioxidant 1 part, and trimethylolpropane hexamethylene diisocyanate 0.3 part dissolved in toluene and self-adhesive adhesive Agent was obtained. The above chelate compound is obtained by dissolving 20 parts of an alkylphenol resin having a softening point of 78 ° C. in toluene, adding 8 parts of magnesium oxide and 0.8 of distilled water to the mixture, stirring for 30 minutes, and then leaving the mixture at room temperature for 10 hours. It is a thing.

Next, the above self-adhesive pressure-sensitive adhesive was applied to a thickness of 40 μm.
On one side of the biaxially oriented polypropylene film
Drying treatment was performed at 00 ° C. for 3 minutes to obtain an adhesive member having an adhesive layer having a thickness of 25 μm.

Example 2 A self-adhesive pressure-sensitive adhesive and a pressure-sensitive adhesive member were obtained in the same manner as in Example 1, except that the blending amount of trimethylolpropane hexamethylene diisocyanate was changed to 5 parts.

Example 3 A self-adhesive adhesive and an adhesive member were obtained in the same manner as in Example 1 except that the amount of trimethylolpropane hexamethylene diisocyanate was changed to 15 parts.

Example 4 70 parts of styrene / isoprene block copolymer, 30 parts of styrene / isoprene / styrene block copolymer, 100 parts of aliphatic petroleum resin, phenolic antioxidant 1
And 5 parts of trimethylolpropane hexamethylene diisocyanate were dissolved in toluene to obtain a self-adhesive pressure-sensitive adhesive, which was used to obtain a pressure-sensitive adhesive member according to Example 1.

Comparative Example 1 A self-adhesive adhesive and an adhesive member were obtained in the same manner as in Example 1 except that trimethylolpropane hexamethylene diisocyanate was not used.

Comparative Example 2 A self-adhesive adhesive and an adhesive member were obtained in the same manner as in Example 4 except that trimethylolpropane hexamethylene diisocyanate was not used.

Comparative Example 3 A self-adhesive pressure-sensitive adhesive and a pressure-sensitive adhesive member were obtained in the same manner as in Example 1 except that the blending amount of trimethylolpropane hexamethylene diisocyanate was 0.1 part.

Comparative Example 4 A self-adhesive pressure-sensitive adhesive and a pressure-sensitive adhesive member were obtained in the same manner as in Example 1 except that the amount of trimethylolpropane hexamethylene diisocyanate was changed to 30 parts.

Evaluation Test The following characteristics were examined for the pressure-sensitive adhesive members obtained in Examples and Comparative Examples. Adhesive force According to JIS Z 0237, the adhesive layer of the adhesive member is placed on a 2 kg rubber roller in an atmosphere of 23 ° C. and 65% RH.
The adhesive was adhered to a stainless steel plate under reciprocating crimping conditions, and the adhesion was examined (180 degree peel, peeling speed 300 mm /
Minutes).

Self-adhesive force Under an atmosphere of 23 ° C. and 65% RH, as shown in FIG.
The adhesive layers of the adhesive member 1 comprising the adhesive layer 1 and the adhesive layer 12
g under a pressure condition of one reciprocation of the rubber roller, peeling off one end of the self-adhesive surface a little, and peeling it off in the 180-degree direction as indicated by the arrow through both ends of the member (peeling speed 300 mm /
Min), and the adhesive strength was examined.

Holding force One end of the self-adhesive surfaces of the adhesive layers of the adhesive member was slightly peeled off, and a load of 500 g was applied to one end of the member, and the peeling distance per hour was examined.

The above results are shown in the following table. * 1: Drops immediately after loading

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a self-adhesion force measuring method.

[Description of Signs] 1: Adhesive member 11: Support base material 12: Adhesive layer

Claims (4)

[Claims] 1. A base polymer comprising a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound,
A self-adhesive adhesive comprising at least a tackifier and a polyfunctional isocyanate compound having two or more isocyanate groups. 2. The method according to claim 1, wherein the base polymer
0 parts by weight, containing 1 to 150 parts by weight of a tackifier, 0.2 to 20 parts by weight of a polyfunctional isocyanate compound,
And a self-adhesive pressure-sensitive adhesive containing 50 parts by weight or less of a rubber-based polymer other than the base polymer. 3. The self-adhesive pressure-sensitive adhesive according to claim 1, wherein the resin coordination chelate compound comprising an alkaline earth metal is contained in an amount of 100 parts by weight or less per 100 parts by weight of the base polymer. 4. A pressure-sensitive adhesive member having a pressure-sensitive adhesive layer comprising the self-adhesive pressure-sensitive adhesive according to claim 1 on one or both surfaces of a supporting substrate.