JPS5949264B2 - self-adhesive adhesive formulations - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel self-adhesive formulation (hereinafter referred to as "self-adhesive formulation") which is not substantially limited by temperature conditions during use and exhibits excellent self-adhesive properties over a long period of time. ) and self-adhesive tapes, sheets, films, or similar articles using the compositions.

As self-adhesive formulations, those based on neoprene rubber and high molecular weight natural rubber are known, and recently, those based on styrene-isoprene-styrene block copolymer have been proposed. In particular, a type in which the block copolymer is used as a base component and an adhesion-imparting resin is blended therewith is attracting attention as having relatively excellent cohesiveness and excellent self-adhesive properties.

However, according to experiments conducted by the present inventors, the type of block copolymer blended with adhesion-promoting resin has a narrow operating temperature range in which it exhibits its excellent self-adhesive properties, such as during winter. When the operating temperature is often below 10°C, there is a tendency for self-adhesiveness to decrease dramatically, and when low molecular weight components such as softeners and plasticizers are added to improve this, It was found that the self-adhesion of the material was significantly reduced.

Another problem is that although the adhesive has good self-adhesive properties at the beginning of use, it has been found that it significantly deteriorates over time. As a result of intensive research, the inventors of the present invention aimed to solve the problem of the usage temperature range and the problem of self-adhesiveness decreasing over time, and as a result, they developed a specific mixture system of block copolymer and adhesion-providing resin. It was discovered that this problem could be solved by blending a rubber with different properties, leading to the present invention.

That is, the present invention provides an adhesive main component consisting of a styrene-isoprene-styrene block copolymer and an adhesion-providing resin, which is substantially incompatible with the copolymer and whose modulus is 100% that of the main component. It is smaller and has a swelling rate of 200
The present invention provides a self-adhesive formulation containing ~5000% rubber vulcanizate.

The styrene-isoprene-styrene block copolymer used in the present invention has the general formula A-B-A (wherein A
has an independently selected average molecular weight of about 5000 to 1250
B is a non-elastomeric polymeric block consisting of styrene having an average molecular weight of about 15,000 to 2.
For example, a copolymer prepared by graft polymerizing a monomer such as methyl methacrylate to the copolymer may also be used.

In addition, as adhesion-providing resins, rosin and its derivatives,
Examples include terpene resins, terpene-modified phenolic resins, phenolic resins, coumaron resins, and petroleum resins.

The adhesive main component consisting of these block copolymers and adhesion-providing resin may contain a rubber additive which is substantially incompatible with the copolymer and whose 100% modulus is smaller than that of the main component. Sulfur is added.

The compounded rubber vulcanizate is such that the rubber raw material is incompatible with the copolymer and has a 100% modulus smaller than that of the main component, and the rubber vulcanizate is moderately vulcanized. Due to the fact that it is dispersed uniformly in lumps in the main component, it gives suitable cushioning properties to self-adhesive formulations, widens the usage temperature range of the formulation, and improves self-adhesion over time. It works to effectively prevent the deterioration of characteristics.

The rubber raw material is not particularly limited as long as it satisfies the above two conditions, but examples include butyl rubber, chlorinated butyl rubber, brominated butyl rubber, polybutadiene rubber,
Examples include ethylene propylene rubber, ethylene propylene diene rubber, nitrile rubber, low crystalline neoprene rubber, and low styrene styrene butadiene rubber. According to experiments conducted by the present inventors, it has been found that among these rubber raw materials, butyl rubber, ethylene propylene rubber, ethylene-propylene diene rubber, and nitrile rubber exhibit the most effective addition effects. However, these rubber raw materials have the main components as they are,
That is, even if the rubber raw material is blended in an unvulcanized state, the desired effect of the present invention cannot be obtained, and the rubber raw material should be blended with the main component in the state of a properly vulcanized rubber vulcanizate. is necessary.

The method of vulcanizing the rubber raw material is not particularly limited, and for example, the following vulcanization method can be used.

Sulfur vulcanization method: As a vulcanizing agent, for example, sulfur, tetramethylthiuram disulfide, tetramethylthiuram monosulfide,
Dipentamethylene lenthiuram tetrasulfide, tetraethylthiuram disulfide, 2-mercaptobenzothiazole, N-cyclohexyl-2-benzothiazole sulfenamide, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, etc. , Oxime vulcanization method: Vulcanizing agents such as p-quinodioxime, p.p'-dibenzoylquinone dioxime, etc. Peroxide vulcanization method: Vulcanizing agents such as dicumyl peroxide, 11-di(
Vulcanization of polyfunctional monomers such as 3.5-trimethylcyclohexane (t-butylperoxy), di(t-butylperoxy)diisopropylbenzene, 2.5-dimethyl-2.5-di(t-butylperoxy)hexane, etc. Method: Examples of vulcanizing agents include ethylene dimethacrylate, divinylbenzene, diallyl phthalate, m-phenylene bismaleimide, tolu, ylene bismaleimide, and other reactive phenol resin vulcanization methods.

Therefore, the degree of vulcanization of the rubber vulcanizate vulcanized by these vulcanization methods is 200 to 5 as determined by the swelling rate measured by the measurement method described below.
000%, preferably in the range of 300 to 3000%. If the swelling ratio is less than 200%, the lumpy rubber vulcanizate blended into the main component will be too hard and the entire compound will be The cushioning properties are insufficient, and the desired self-adhesive properties cannot be obtained, and if it exceeds 5000%, the unvulcanized rubber content is large, and as with non-vulcanized rubber, it will become unvulcanized over time. The rubber tends to bleed onto the surface of the self-adhesive compound layer, significantly reducing its self-adhesive strength.

The self-adhesive compound of the present invention is composed of a block copolymer, an adhesion-providing resin, and a rubber vulcanizate obtained by moderately vulcanizing a specific rubber raw material. It is desirable that the following proportions be used for each 100 parts by weight of the block copolymer. That is, the amount of the resin is 10 to 150 parts by weight, and the amount of the rubber vulcanizate is 3 to 100 parts by weight.

If the resin content is less than 10 parts by weight, the adhesiveness of the self-adhesive compound will be poor, and if it is more than 150 parts by weight, the low temperature properties will be insufficient and the cohesive force of the compound will decrease, making it impossible to obtain good self-adhesive properties. Also, if the rubber vulcanizate is less than 3 parts by weight, no effect is observed, and if it is more than 100 parts by weight, the surface becomes rough when the compound is spread in a layer, resulting in an unfavorable appearance.
This is because the self-adhesiveness is significantly reduced.

Known compounding agents such as fillers, pigments, softeners, and anti-aging agents may be added to such a compounding system consisting of the block copolymer, adhesion-promoting resin, and rubber vulcanizate as necessary. However, it will be understood from the above explanation that it is not preferable to add natural rubbers which have excellent compatibility with the block copolymer.

The self-adhesive composition of the present invention can be produced by, for example, adding and mixing a masticated rubber vulcanizate to an adhesive main component solution consisting of a block copolymer and an adhesion-promoting resin; The composition can be formed by physically mixing the adhesive with the main component (or by dissolving it in an organic solvent, or by mixing frozen and crushed rubber vulcanizate powder with the main adhesive component). can.

The self-adhesive formulation thus composed consists of polyester,
It is coated or transferred onto the surface of a carrier such as a plastic film (or sheet) such as polyvinyl chloride or polyolefin, or paper such as Japanese paper or crepe paper, to a thickness of generally 10 to 150 μm (solid content), and 15009 /20
mT! A self-adhesive tape, sheet, film, or similar article having a self-adhesive force of t width or more and a self-adhesive holding force of 10 mm/Hr or less is produced.

Such self-adhesive tapes or similar products can be effectively used for binding, fixing, or packaging electronic components, construction materials, agricultural materials, fresh flowers, vegetables, and the like.

Examples of the present invention will be shown below. The text middle part means the weight part. Example 1 Styrene-isoprene-styrene block copolymer 10
0 parts, 30 parts of petroleum resin, 40 parts of rosin modified resin and 2 parts of phenol anti-aging agent were added and kneaded uniformly in a kneader to give a 100% modulus of 6 kg/(177!
Obtain the adhesive main component.

Next, to this main component, a rubber vulcanizate obtained by vulcanizing the rubber compounds shown in the following A-G and H-K (comparative examples) by a conventional method was added, and 10 types of self-adhesive compounds were prepared. I got it. Compatibility: The self-adhesive strength and self-adhesive holding power in Table 1 are determined by the amount of prok copolymer in the solution of the adhesive main component adjusted to 30% by weight in solids with toluene. In order to evaluate the composition, it was coated to a thickness of 30 μm on the treated surface of a 50 μm thick biaxially oriented polypropylene film which had been subjected to undercoating treatment.

The evaluation method in Table 1 is as follows.

100% modulus: Using a sample body (unvulcanized rubber) with cross-sectional area 1i1 length 10011, effective sample length 3011, tensile speed 30011/-
, the modulus is measured at a temperature of 20° C., and the stress at 100% elongation (Kg/Cd) is determined.

Swelling rate: After immersing the rubber vulcanizate piece 19 in toluene at 20° C. for 48 hours, the weight change of the rubber vulcanizate piece is measured and calculated using the following formula.

Claims (1)

[Scope of Claims] 1. An adhesive main component consisting of a styrene-isoprene-styrene block copolymer and an adhesion-providing resin is substantially incompatible with the copolymer, and its 100% modulus is Smaller than the main component and has a swelling rate of 200-5000
Self-adhesive adhesive formulation containing % rubber vulcanizate. 2. The self-adhesive adhesive composition according to claim 1, wherein the adhesion-imparting resin is blended in an amount of 10 to 150 parts by weight based on 100 parts by weight of the copolymer. 3. The self-adhesive adhesive composition according to claim 1, wherein the rubber is at least one selected from the group of butyl rubber, ethylene propylene rubber, ethylene propylene diene rubber, and nitrile rubber. 4 The rubber vulcanizate is 3 parts by weight based on 100 parts by weight of the copolymer.
The self-adhesive adhesive composition according to claim 1, wherein the self-adhesive composition is blended in an amount of 100 parts by weight.