JPH07188633A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a one-pack adhesive composition having good shelf life and being excellent in initial, ordinary-state and high-temperature adhesive powers. CONSTITUTION:A modified styrene block copolymer obtained by grafting a styrene block copolymer with an unsaturated carboxylic acid or its derivative (e.g. SEBS modified with a carboxylic acid) and serving as a base elastomer, an alkylphenol resin (e.g. t-butylphenol resin) and a metal oxide (e.g. magnesium oxide) or hydroxide are incorporated into an organic solvent (e.g. toluene).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition having a styrenic block copolymer having improved initial adhesive strength, cohesive strength and heat resistance.

[0002]

Conventionally, styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block (SBS) copolymer and styrene-
Ethylene / butylene-styrene block copolymer (SE
A composition based on a styrene block copolymer such as BS) elastomer and added with a tackifier is
It is used as a hot-melt type adhesive, a solvent type adhesive, and a pressure-sensitive adhesive, but it can only be used in places where it is limited due to its shortcomings of insufficient initial adhesive strength, cohesive strength, and heat resistance.

[0003]

The object of the present invention is to improve the initial adhesive strength, cohesive strength, and heat resistance of the adhesive based on the above-mentioned styrenic block copolymer, which is a one-pack type and has excellent storage stability. An object is to provide an adhesive composition.

[0004]

According to the present invention, a modified product obtained by grafting an unsaturated carboxylic acid or a derivative thereof on a styrene block copolymer is used as a base elastomer, and an alkylphenol resin and a metal oxide or metal hydroxide are used in an organic solvent. It is contained in the adhesive composition.

In the adhesive composition of the present invention, a modified product (hereinafter referred to as a modified block copolymer) obtained by grafting an unsaturated carboxylic acid or its derivative on a styrene block copolymer as a base elastomer is obtained as follows. be able to.

That is, the above-mentioned SIS, SBS, SEB
Examples of unsaturated carboxylic acids or their derivatives to be grafted onto styrene block copolymers such as S copolymer elastomers are maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, crotonic acid, cis-4.
Examples thereof include cyclohexane-1,2-dicarboxylic acid, and among these, dicarboxylic acid anhydride is preferable, and maleic anhydride is particularly preferable.

The content of unsaturated carboxylic acid or its derivative in the modified block copolymer of the present invention is 0.01 to
It is 30% by weight, preferably 0.05 to 10% by weight. If it is less than 0.01% by weight, the reactivity with metal is poor and sufficient strength cannot be obtained. When it is 30% by weight or more, the reactivity is too strong and gelation is likely to occur, which causes inconvenience in use such as storage stability and pot life.

The modified block copolymer of the present invention can be produced by
Grafting the styrenic block copolymer and the unsaturated carboxylic acid or the derivative thereof into the styrenic block copolymer or the derivative thereof in a molten state or a solution state, with or without a radical initiator. Is obtained by If necessary, it can be used in a blend with a conventional unmodified styrenic block copolymer.

The alkylphenol resin used in the present invention is
It is obtained by the condensation reaction of alkylphenol and formaldehyde, and is a thermoreactive resin. As the alkyl group, para-tertiary-butylphenol is generally used.

The amount of the alkylphenol resin added is 1 to 100 parts by weight of the modified block copolymer.
It is 200 parts by weight, preferably 5 to 100 parts by weight. If the addition amount is too small, the storage stability as a one-pack type deteriorates and the viscosity increases with time. On the contrary, when the amount is large, the adhesive layer becomes brittle and the adhesive retention time becomes short.

The metal oxide or metal hydroxide in the present invention means an oxide or hydroxide of a metal cation of Group 2-8. Preferred are Group 2 metal oxides or metal hydroxides, specifically magnesium oxide, calcium oxide, magnesium hydroxide, calcium hydroxide and the like. A chelation reaction product with an alkylphenol resin can also be used. These are used alone or in combination.

The amount of the metal oxide or metal hydroxide added is generally 0.1 to 100 parts by weight based on 100 parts by weight of the modified block copolymer. If the amount added is small, the heat resistance cannot be improved, and if it is large, it precipitates in the solution.

As the organic solvent used for preparing the present adhesive, any solvent that can dissolve the modified block copolymer can be used, and examples thereof include hydrocarbons, chlorinated hydrocarbons, ketones and esters. . These may be used alone or in combination depending on the purpose of use.

Specific examples of these organic solvents include hydrocarbons such as toluene, xylene, cyclohexane, n-hexane, n-heptane, petroleum naphtha, gasoline and petroleum spirit. Chlorinated hydrocarbons include methylene chloride, chloroform, carbon tetrachloride, trichloroethane, dichloroethane and the like. As the ketones, acetone, methyl ethyl ketone, methyl-n-
Propyl ketone, etc. Esters include ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-
There are n-butyl and the like.

In the present invention, in addition to the above components, modifiers such as tackifiers, inorganic fillers, pigments and plasticizers are also used, if necessary.

As the tackifier, any of those used in conventional hot melt pressure sensitive adhesives and solvent type adhesives can be used. For example, polyterpenes, rosin esters, coumarone-indene resins, terpene phenol resins and petroleum resins. Can be mentioned. Examples of petroleum-based resins include aliphatic cyclic hydrocarbon resins and aromatic hydrocarbon resins.

Examples of the inorganic filler include calcium carbonate, silica, talc and glass fiber. Examples of pigments include titanium oxide, zinc oxide, iron oxide and mica. Examples of the plasticizer include dibutyl phthalate and dioctyl phthalate. As a stabilizer, a hindered phenol type,
Examples include hydrazine type and benzophenone type.

As a method for producing the present adhesive, a modified block copolymer, an alkylphenol resin, a metal oxide or a metal hydroxide, and a modifier such as a tackifier used as necessary are added to an organic solvent. Then, it is obtained by dissolving and dispersing. The non-volatile content of the adhesive can be adjusted according to the desired application, but is generally 10-5.
It is 0% by weight.

[0019]

EXAMPLES The present invention will be described below with reference to examples. Parts indicate parts by weight.

Examples 1 to 4, Comparative Examples 1 to 3 Commercially available carboxylic acid-modified SE as a modified block copolymer
Craneton FG1901X (manufactured by Shell Chemical Co.) of BS, Kraton G1650 as unmodified SEBS
(Manufactured by Shell Chemical Co., Ltd.), a commercial tert-butylphenol resin CKM1634 as an alkylphenol resin.
(Showa High Polymer Chemical Co., Ltd.), and the resin (45 parts) and magnesium oxide (MgO) (5 parts) in toluene (50 parts).
Part) CKM1634-
MgO, magnesium oxide (MgO) as metal oxide
And calcium oxide (CaO), and rosin ester super ester A100 (manufactured by Arakawa Chemical Co., Ltd.) as a tackifier, respectively, in an organic solvent of toluene.
The mixture was mixed and dispersed in the addition amounts shown in to obtain the adhesives of Examples 1 to 4 and Comparative Examples 1 to 4.

Next, each adhesive was applied onto two sheets of No. 9 canvas with a brush of about 300 g / m ^2, and the open time was set to 30.
After taking, pasting, 3Kg / c in press machine
The test piece was pressed under a pressure of m ² and cut into a piece of 25 mm × 150 mm.

Each test piece was tested at 20 ° C. for 30 minutes after the initial adhesive strength at 20 ° C. (initial, 20 ° C.) and initial heat resistant adhesive strength at 60 ° C. (initial, 60 ° C.), and 20 ° C.
Normal adhesive strength (normal state,
Normal heat resistant adhesive strength at 20 ℃ and 60 ℃ (normal, 60
C) in accordance with JIS K6854 "Peeling adhesive strength test method for adhesives", T-type peel adhesive strength (Kgf / 25 m
m width) was measured. The results are shown in Table 1.

Next, for storage stability, the adhesive immediately after dissolution was adjusted to 25 ° C., and the viscosity (cp / 25 ° C.) was measured using a Brookfield type rotary viscometer (BM type, rotor No. 2, 30 rpm value). did. After that, the adhesive was stored in a thermostatic chamber at 40 ° C. for 3 months in a closed container, taken out, the adhesive was adjusted to 25 ° C. again, and the viscosity (cp / 25 ° C.) was measured by the method described above. The results are shown in Table 1.

[0024]

[Table 1]

[0025]

As is clear from Table 1, the adhesive obtained by adding the alkylphenol resin and the metal oxide to the modified block copolymer of the present invention is excellent in initial, normal state and heat resistance. It also has good storage stability.

Claims (1)

[Claims] 1. A modified product obtained by grafting an unsaturated carboxylic acid or a derivative thereof on a styrene block copolymer as a base elastomer, and containing an alkylphenol resin and a metal oxide or metal hydroxide in an organic solvent. Adhesive composition.