JPH0987599A - Tacky adhesive composition, and tacky adhesive sheet and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a very excellent tacky adhesive compsn. and a very excellent tacky adhesive sheet and the like by selecting a tacky adhesive compsn. which has excellent aging characteristics and does not discolor the compsn. itself, a carrier, and an adherend. SOLUTION: This compsn. prepd. mainly from a rubberlike polymer (e.g. a natural or synthetic rubber), contains 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert- butylanilino)-1,3,5-triazine in an amt. of 0.05-5wt.% of the polymer. A layer of the compsn. is formed on a carrier to obtain a tacky adhesive article in the form of sheet, tape, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition using a rubbery polymer such as natural rubber or synthetic rubber,
The present invention also relates to pressure sensitive adhesive sheets which are provided in the form of sheet, tape or the like by providing this pressure sensitive adhesive composition on a support.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive composition using natural rubber or synthetic rubber generally has a drawback that the pressure-sensitive adhesive is deteriorated by heat and light, and in particular, the cohesive force is lowered with time. In order to prevent this, an appropriate antiaging agent is included in the adhesive in advance.

However, when a phenol anti-aging agent, which is known to bring about a good result in the aging characteristics of the pressure-sensitive adhesive, is added, the pressure-sensitive adhesive and the support (particularly white support) on which it is provided are colored pink or When it is changed to brown or is applied to an adherend, such as a wallpaper, there is a drawback that the adherend is discolored.

As means for preventing such discoloration,
As an anti-aging agent to be added to the pressure-sensitive adhesive, a method in which a benzimidazole-based one is used in addition to a phenol-based one (Japanese Patent Publication No. 57-52387), and polyvinyl chloride is used as a support. In this case, a method is known in which epoxidized soybean oil is contained in the support to prevent discoloration of the support (Japanese Patent Laid-Open No. 7-41741).

[0005]

DISCLOSURE OF THE INVENTION The present invention prevents discoloration of an adhesive, a support and an adherend by a method different from the above-mentioned conventional methods, and further improves the time-dependent characteristics of the adhesive and the above discoloration prevention. It is intended to provide an excellent pressure-sensitive adhesive composition and pressure-sensitive adhesive sheets.

[0006]

[Means for Solving the Problems] The inventors of the present invention have made extensive studies in order to achieve the above-mentioned object, and as a result, in the pressure-sensitive adhesive, instead of a phenol anti-aging agent, a specific anti-aging agent was used. It was found that the compounding of the composition gives the adhesive excellent in aging characteristics, and very good results can be obtained in preventing discoloration of the adhesive, the support and the adherend, and thus the present invention has been completed.

That is, the present invention relates to an adhesive composition using a rubbery polymer such as natural rubber or synthetic rubber,
2,4-bis- (n-octylthio) -6- (4-hydroxy-) per 100 parts by weight of the above rubbery polymer.
3,5-di-tert-butylanilino) -1,3,5
-The present invention relates to a pressure-sensitive adhesive composition containing 0.05 to 5 parts by weight of triazine. The present invention also relates to a sheet-shaped or tape-shaped pressure-sensitive adhesive sheet, which has a layer of the pressure-sensitive adhesive composition having the above structure on a support made of polyvinyl chloride or the like. It is a thing.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive composition of the present invention comprises a rubbery polymer such as natural rubber or synthetic rubber as a main component, and contains additives such as tackifying resin, softening agent, pigment and filler. It may be a solution type, a water dispersion type, or a hot melt type.

As the rubbery polymer and the above-mentioned various additives, any of the conventionally known ones can be used, and the kinds and blending amounts thereof are not particularly limited. In the present invention, in such an adhesive composition, further as an antioxidant,
2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino)-
It is characterized by containing 1,3,5-triazine.

This antioxidant has an n-octylthio group at the 2,4-position of the 1,3,5-triazine ring, and 4-hydroxy-3,5-di-tert- at the 6-position.
A compound having a butylanilino group, as an example of a commercially available product, manufactured by Ciba-Geigy Co., Ltd. under the trade name “IRGANOX 56
5 ”and the like.

The amount of the antioxidant added is 0.05 to 5 parts by weight, preferably 0.5 to 3 parts by weight, per 100 parts by weight of the rubbery polymer. If the amount is less than 0.05 parts by weight, the time-dependent characteristics of the pressure-sensitive adhesive will deteriorate. Further, even if the amount is more than 5 parts by weight, the effect is not significantly increased, which is disadvantageous in cost.

In the present invention, the pressure-sensitive adhesive composition having such a constitution is usually coated on a support to have a thickness of 5 after drying.
By coating so as to have a thickness of up to 50 μm, it becomes a sheet-shaped or tape-shaped adhesive sheet. As the support, polyethylene, polypropylene, polyvinyl chloride,
Films such as polyester and cellophane, and paper materials such as Japanese paper, crepe paper and kraft paper having a thickness of about 20 to 200 μm are usually used.
In the case of a film made of polyvinyl chloride, it is usual to add a compounding agent such as a plasticizer, a stabilizer and a pigment in addition to the above polyvinyl chloride to form a film. If necessary, the surface of the support film may be subjected to an undercoat treatment or a back treatment.

[0013]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. In the following, "parts" means "parts by weight".

Example 1 100 parts of natural rubber (SMR-L), terpene resin (trade name "YS resin Px-100 manufactured by Yasuhara Chemical Co., Ltd."
0 ") and 100 parts of an anti-aging agent (trade name" Irganox 565 "manufactured by Ciba-Geigy Co., Ltd.)" were dissolved in toluene to prepare a solution of an adhesive composition. Next, this solution was applied onto a biaxially stretched polypropylene film having a thickness of 40 μm so that the thickness after drying would be 30 μm, and dried to prepare an adhesive tape.

Comparative Example 1 A solution of the pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the antioxidant was not added. Further, an adhesive tape was produced in the same manner as in Example 1 using the solution of this adhesive composition.

Comparative Example 2 As an antiaging agent, 2 parts of a phenol type antiaging agent (trade name "NOKURAKU NS-5" manufactured by Ouchi Shinko Chemical Co., Ltd.) was used in place of "IRGANOX 565". A solution of the pressure-sensitive adhesive composition was prepared in the same manner as in Example 1.
Further, using this solution, an adhesive tape was produced in the same manner as in Example 1.

Comparative Example 3 As an anti-aging agent, 2 parts of a phenol type anti-aging agent (trade name "Nokuratsuku NS-5" manufactured by Ouchi Shinko Chemical Co., Ltd.) were used instead of "Irganox 565", and Benzimidazole.
Anti-aging agent (trade name "SUMILIZER" manufactured by Sumitomo Chemical Co., Ltd.
A solution of the adhesive composition was prepared in the same manner as in Example 1 except that 1 part of "MB") was used. Further, using this solution, an adhesive tape was produced in the same manner as in Example 1.

With respect to the adhesive tapes of Example 1 and Comparative Examples 1 to 3 above, discoloration of the adherend, discoloration of the adhesive tape (support and adhesive), aging characteristics of the adhesive (cohesive strength) Change) was investigated in the following manner. The results were as shown in Table 1 below.

<Discoloration of adherend> Adhesive tape was attached to a white wallpaper made of polyvinyl chloride and stored at 70 ° C for 20 days, then the adhesive tape was peeled off and the discolored state of the wallpaper was examined. It was No discoloration was evaluated as ◯, and discoloration was evaluated as x.

<Discoloration of Adhesive Tape> The adhesive tape was placed in a Sunshine Weatherweather (hereinafter referred to as WOM) and an oven at 70 ° C., and the adhesive tape was visually observed. The state of discoloration of the support and the adhesive was examined. No discoloration was evaluated as ◯, and discoloration was evaluated as x.

<Characteristics of adhesive with time (change in cohesive strength)> An adhesive tape was attached to a stainless steel plate, and WOM and 70 were used.
After putting it in an oven at ℃, the adhesive residue was examined when it was peeled loosely. No adhesive residue was evaluated as ◯, and adhesive residue was evaluated as ×.

[0022]

[Table 1]

Example 2 40 parts of natural rubber (RSS grade 1), styrene-butadiene copolymer rubber (trade name "Nitzpol 15 manufactured by Nippon Zeon Co., Ltd."
02 ") 60 parts, terpene-based resin (Yasuhara Chemical Co., Ltd., trade name" YS Resin Px-1000 ") 80 parts, anti-aging agent (Ciba-Geigy trade name" Irganotex 565 "), 2 parts dissolved in toluene Then, a solution of the pressure-sensitive adhesive composition was prepared.

Separately, 100 parts of polyvinyl chloride having an average degree of polymerization of 1,000, 50 parts of dioctyl phthalate,
A mixture consisting of 3 parts of a Ba—Zn composite stabilizer and 2 parts of a white pigment was kneaded, and the mixture was calendered to a thickness of 170.
A μm film was prepared. Next, a solution of the pressure-sensitive adhesive composition prepared by the above-mentioned method was dried on the support made of this polyvinyl chloride film so that the thickness after drying was 30 μm.
To obtain an adhesive tape.

Comparative Example 4 As an antiaging agent, 2 parts of a phenol type antiaging agent (trade name "NOKRATSUK NS-5" manufactured by Ouchi Shinko Chemical Co., Ltd.) was used in place of "IRGANOX 565". A solution of the pressure-sensitive adhesive composition was prepared in the same manner as in Example 2.
Further, using this solution, an adhesive tape was produced in the same manner as in Example 2.

Comparative Example 5 As an anti-aging agent, 2 parts of a phenol type anti-aging agent (trade name "Nokuratsuku NS-5" manufactured by Ouchi Shinko Chemical Co., Ltd.) were used instead of "Irganox 565", and Benzimidazole.
Anti-aging agent (trade name "SUMILIZER" manufactured by Sumitomo Chemical Co., Ltd.
A solution of the adhesive composition was prepared in the same manner as in Example 2 except that 1 part of "MB") was used. Further, using this solution, an adhesive tape was produced in the same manner as in Example 2.

Comparative Example 6 20 parts of epoxidized soybean oil (trade name "W-100EL" manufactured by Dainippon Ink and Chemicals, Inc.) was added to the composition for the preparation of a support made of polyvinyl chloride film. In the same manner as in Comparative Example 4, an adhesive tape was produced.

With respect to the adhesive tapes of Example 2 and Comparative Examples 4 to 6 above, discoloration of the adherend, discoloration of the adhesive tape (support and adhesive), and time-dependent characteristics of the adhesive (cohesive strength) Change) was examined in the same manner as described above. The results are as shown in Table 2.

[0029]

[Table 2]

As is clear from the results of Tables 1 and 2 above, according to the adhesive tapes of Examples 1 and 2 of the present invention,
As the time-dependent characteristics of the adhesive, the change in cohesive force over time is suppressed, and there is no discoloration of the support or adhesive of the adhesive tape, and no discoloration of the adherend. I understand.

[0031]

As described above, according to the present invention, the addition of a specific anti-aging agent to the pressure-sensitive adhesive makes the pressure-sensitive adhesive excellent in aging characteristics and discolors the pressure-sensitive adhesive tape and the adherend. It is possible to provide a pressure-sensitive adhesive composition and pressure-sensitive adhesive sheets which are free from visible defects.

Claims (3)

[Claims] 1. A pressure-sensitive adhesive composition using a rubbery polymer such as natural rubber or synthetic rubber, wherein 2,4-bis- (n-octylthio) -6-per 100 parts by weight of the rubbery polymer. (4-hydroxy-3,5-di-tert
-Butylanilino) -1,3,5-triazine to 0.0
An adhesive composition comprising 5 to 5 parts by weight. 2. A pressure-sensitive adhesive sheet having a layer of the pressure-sensitive adhesive composition according to claim 1 on a support. 3. The adhesive sheet according to claim 2, wherein the support is made of polyvinyl chloride film.