JP2530688B2 - Acrylic adhesive composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an acrylic pressure-sensitive adhesive composition having excellent heat resistance.

(Prior Art) Acrylic adhesives are widely used because of their excellent adhesive performance such as adhesive strength, holding power, and tack.

(Problems to be Solved by the Invention) However, such conventional acrylic pressure-sensitive adhesives have a problem that they have insufficient heat resistance and cannot withstand use at high temperatures.

The present invention is intended to solve the above problems, and an object thereof is to provide an acrylic pressure-sensitive adhesive composition having excellent heat resistance.

(Means for Solving the Problems) The acrylic pressure-sensitive adhesive composition of the present invention is directly bonded to 100 parts by weight of an acrylic copolymer containing a hydroxyl group or / and a carboxyl group as a functional group and a silicon atom in a molecule. Containing 10 to 100 parts by weight of an organopolysiloxane having a phenyl group and having a hydroxyl group and / or an alkoxy group as a functional group, a silane coupling agent, and a curing catalyst, thereby achieving the above object. It

The acrylic copolymer used in the present invention contains a hydroxyl group and / or a carboxyl group as a functional group. Such an acrylic copolymer has, for example, an alkyl group having 4 to 4 carbon atoms.
0.1 to 10 mol of a functional monomer such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid, etc., alone or in a mixture with 12 (meth) acrylic acid alkyl ester. % To obtain it.

In addition to the above functional monomers, vinyl acetate,
Acrylamide, acrylonitrile, styrene, vinyl methyl ether, vinylpyrrolidone, vinyl chloride, butadiene and the like may be copolymerized. In particular, an acrylic copolymer having a hydroxyl group as a functional group is blended with a silane coupling agent described below, and it is difficult to gel even when it is stored as a solution for a long time, and also has good heat resistance, which is suitable. Used.

Further, the organopolysiloxane used in the present invention has a phenyl group directly bonded to a silicon atom in the molecule and a hydroxyl group and / or an alkoxy group as a functional group. Such organopolysiloxane has good compatibility with the acrylic copolymer, and mainly imparts heat resistance to the composition without causing cloudiness in the composition.

The above-mentioned organopolysiloxane is, for example, phenyltrichlorosilane, diphenyldichlorosilane, phenyltrialkoxysilane, diphenyldialkoxysilane or a mixture thereof, and if necessary, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, methyldisilane. It is obtained by hydrolyzing a mixture of chlorosilane, trichlorosilane, vinylmethyldichlorosilane, or a mixture of one or more alkoxysilanes corresponding thereto.

The organopolysiloxane is blended in an amount of 10 to 100 parts by weight based on 100 parts by weight of the acrylic copolymer. If the blending amount is less than 10 parts by weight, the heat resistance of the composition will be insufficient, and if it is more than 100 parts by weight, the adhesive strength and holding power of the composition will be reduced.

Further, the silane coupling agent used in the present invention co-crosslinks the above acrylic copolymer and the organopolysiloxane. Examples of the silane coupling agent include (C ₆ H ₅ ) ₂ Si (OH) ₂ , C ₆ H ₅ (CH ₃ ) ₂ SiOH, C ₆ H ₅ (C
_{H 3) Si (OH) 2} , (CH 3) 2 Si (OCH 3) 2, (C 6 H 5) 2 Si
_{(OCH 3) 2, CH 2} = CH-Si (OC 2 H 5) 3, C 6 H 5 (CH 3) Si
(OCH ₃ ) ₂ , NH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , NH ₂ CH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , HSCH ₂ CH ₂ CH ₂ Si (OC
H ₃ ) ₃ , OCNCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , etc.

Particularly, a silane coupling agent having an isocyanate group such as OCNCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ has good compatibility with an acrylic copolymer, storage stability, and reactivity, and is preferably used. To be The above-mentioned silane coupling agent is generally added in an amount of 1 to 50 parts by weight based on 100 parts by weight of the acrylic copolymer.

As the curing catalyst, a catalyst such as an organic acid salt of a metal such as zinc, titanium, tin or lead, or an amine compound which has been conventionally used for curing organopolysiloxane is used. However, when such a catalyst is blended with an acrylic copolymer, gelation and white turbidity may occur.

However, the phosphoric acid ester-based curing catalyst gels,
It is suitable because it does not cause cloudiness. Examples of such phosphoric acid ester-based curing catalysts include orthophosphoric acid esters and acidic phosphoric acid esters such as trisdichloropropyl phosphate, butyl azide phosphate, tributoxyethyl phosphate, trimethyl phosphate, tributyl phosphate. The above curing catalyst is an acrylic copolymer
Generally, 0.1 to 10 parts by weight is mixed with 100 parts by weight.

In the acrylic pressure-sensitive adhesive composition of the present invention, for example, the above acrylic copolymer and organopolysiloxane are dissolved in a solvent such as toluene or ethyl acetate, and a silane coupling agent and a curing catalyst are mixed and dissolved therein. Can be obtained. In addition, a compounding agent for a pressure-sensitive adhesive that is normally used may be added to this.

(Action) In the acrylic pressure-sensitive adhesive composition of the present invention, the acrylic copolymer and the organopolysiloxane are finally co-crosslinked well with the silane coupling agent by the action of the curing catalyst. The co-crosslinking can be carried out at the usual drying temperature of the acrylic pressure-sensitive adhesive.

(Example) Hereinafter, the Example and comparative example of this invention are shown.

Example 1 100 parts by weight of a toluene / ethyl acetate solution of an acrylic pressure-sensitive adhesive composed of an acrylic copolymer having a carboxyl group as a functional group (solid content: 35% by weight, manufactured by Soken Chemical Co., Ltd.)
To 7 parts by weight and 0.1 part by weight of tertiary amine were added, and this was placed in a flask and reacted at 80 ° C. for 2 hours in a nitrogen stream.

Then, a mixture of 25 parts by weight of methylphenyl polysiloxane containing a hydroxyl group as a functional group, trisdichloropropyl phosphate and butyl acid phosphate.
2 parts by weight were added and the reaction product was obtained by stirring in a nitrogen stream at 90 ° C. for 1 hour.

This reaction product was used as a polyester film (38 μm thick)
Apply it to the top so that the thickness of the solid component is 25 μm, and apply at 120 ° C for 3
After drying for 0 minutes, an acrylic adhesive tape was obtained. With respect to this acrylic pressure-sensitive adhesive tape, tack, SP adhesive strength, 120 ° C holding power, and 200 ° C heat resistance were measured according to JIS Z-0237. The results are shown in Table 1.

For 120 ° C holding power, attach a sample to a stainless steel plate with an attachment area of 25 mm × 25 mm and apply a load of 1 kg to 120 ° C × 60
The length of the terminal deviation after the measurement was measured. Regarding the heat resistance at 200 ° C, a sample was attached to a stainless steel plate, and the adhesive residue state at the time of peeling after 200 ° C x 30 minutes was observed.

Example 2 Toluene / ethyl acetate solution of acrylic pressure-sensitive adhesive consisting of acrylic copolymer having hydroxyl group as functional group 10
OCNCH ₂ C to 0 parts by weight (solid content 32% by weight, manufactured by Soken Chemical Industry Co., Ltd.)
_{H 2 CH 2 Si (OCH 3} ) 3 6 parts by weight was added, which was reacted for 1 hour at 60 ° C. in a nitrogen stream into a flask and allowed to stand 2 days at room temperature.

Then, a mixture of 17 parts by weight of methylphenylpolysiloxane containing a hydroxyl group as a functional group, trisdichloropropyl phosphate and butyl acid phosphate.
2 parts by weight were added and the reaction product was obtained by stirring in a nitrogen stream at 90 ° C. for 1 hour.

This reaction product was used as a polyester film (38 μm thick)
Apply it to the top so that the thickness of the solid part is 25 μm, and
After drying for 5 minutes, an acrylic adhesive tape was obtained. With respect to this acrylic adhesive tape, the tack, SP adhesive strength, 120 ° C. holding power and 200 ° C. heat resistance were measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A toluene / ethyl acetate solution of an acrylic pressure-sensitive adhesive composed of an acrylic copolymer having a carboxyl group as a functional group used in Example 1 was applied to a polyester film (38 μm).
m)) so that the solid component thickness is 25 μm.
It was dried at 0 ° C for 30 minutes to obtain an acrylic pressure-sensitive adhesive tape. With respect to this acrylic pressure-sensitive adhesive tape, in the same manner as in Example 1, tack, SP adhesive strength, 120 ° C holding power, and 200 ° C heat resistance were measured. The results are shown in Table 1.

Comparative Example 2 Toluene, an acrylic pressure-sensitive adhesive composed of an acrylic copolymer having a hydroxyl group as a functional group used in Example 2
Apply ethyl acetate solution onto polyester film (38μm thick) so that the solid component thickness becomes 25μm, and then at 15 ℃ at 15 ℃.
After drying for a minute, an acrylic adhesive tape was obtained. With respect to this acrylic adhesive tape, the tack, SP adhesive strength, 120 ° C. holding power and 200 ° C. heat resistance were measured in the same manner as in Example 1. The results are shown in Table 1.

(Effects of the Invention) As described above, the acrylic pressure-sensitive adhesive composition of the present invention has good heat resistance because the acrylic copolymer and the organopolysiloxane are satisfactorily co-crosslinked with the silane coupling agent by heating. Excellent and can withstand use at high temperature, for example 200 ° C.

Further, the above-mentioned co-crosslinking can be carried out at a drying temperature of an acrylic pressure-sensitive adhesive that is usually performed, for example, 120 ° C., and since high temperature is not required, low cost and good quality acrylic pressure-sensitive adhesive tape, etc. It has the advantage that the product can be obtained.

Claims (1)

(57) [Claims] 1. A 100 parts by weight of an acrylic copolymer containing a hydroxyl group and / or a carboxyl group as a functional group and a phenyl group directly bonded to a silicon atom in the molecule, and a hydroxyl group and / or an alkoxy group as a functional group. An acrylic pressure-sensitive adhesive composition containing 10 to 100 parts by weight of an organopolysiloxane having silane, a silane coupling agent, and a curing catalyst.