JP2002309213A - Pressure-sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition which has suitable pressure-sensitive adhesivity and does not remain the adhesive on an adherend after peeling. SOLUTION: This pressure-sensitive adhesive composition comprises a styrene- isoprene-styrene block copolymer, a tackifying hydrocarbon resin, a softener, and an antioxidant, provided the contents of styrene-isoprene diblocks in the block copolymer are 40 wt.% or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt pressure-sensitive adhesive containing a styrene-isoprene-styrene block copolymer as a main component.

[0002]

2. Description of the Related Art Since a pressure-sensitive adhesive has a function of bonding a solid to a solid while maintaining a constant viscosity, it is necessary to peel off the adhesive after the bonding, for example, a packaging tape, an outdoor marking tape, a medical use. It is widely used in a wide range of fields such as tapes.

[0003] Solvent-based acrylic pressure-sensitive adhesives have been widely used as such pressure-sensitive adhesives because they are relatively inexpensive and easy to use. However, in recent years, hot melt pressure-sensitive adhesives have been widely used as medical pressure-sensitive adhesives and the like since the environmental problems have been highlighted and various restrictions have been imposed.

[0004] Such a hot-melt pressure-sensitive adhesive has a moderate adhesive strength and a property that it is not easily peeled off, and once peeled off, the pressure-sensitive adhesive itself remains on the joint surface. It is necessary to eliminate the inconvenience (adhesive residue) caused by the above. Glue residue causes a deterioration of the product for the medical adhesive, for example, when the applied patch leaves itch on the skin or deteriorates a feeling of use.

Therefore, there is a demand for a pressure-sensitive adhesive that satisfies the necessary requirements for the adhesive force, that has a sufficiently small amount of adhesive residue, and that satisfies both properties simultaneously.

[0006] However, in the development of the pressure-sensitive adhesive composition, studies on the adhesive force have been sufficiently conducted so far, but it has been found that the adhesive force and the adhesive residue have been studied based on a specific index. In particular, pressure-sensitive adhesive compositions for medical use have not been properly studied to satisfy both requirements.

[0007]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a pressure-sensitive adhesive composition which has an appropriate adhesive strength and simultaneously satisfies the problem of adhesive residue.

[0008]

The present invention relates to a pressure-sensitive adhesive composition comprising a styrene-isoprene-styrene block copolymer, a hydrocarbon-based tackifying resin, a softener, and an antioxidant, -The pressure-sensitive adhesive composition, characterized in that, in the isoprene-styrene block copolymer, the content ratio of the styrene-isoprene-block is 40% by weight or less in the total styrene-isoprene-styrene block copolymer. Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention is a composition that can be used as a pressure-sensitive adhesive, the main component of which is a styrene-isoprene-styrene block copolymer.
In the styrene-isoprene-styrene block copolymer, the ratio of styrene-isoprene diblock present therein (hereinafter, this ratio is also referred to as “SI diblock amount”) is determined by the total styrene-isoprene-styrene block copolymer. It is 40% by weight or less in the coalescence. SI diblock amount
If it exceeds 40% by weight, the polymer as the main component becomes too soft, and it becomes impossible to prevent the occurrence of the adhesive residue phenomenon.

[0010] The present inventors have studied what causes the phenomenon of adhesive residue actually occurring when using an adhesive, and found that it is closely related to the above-mentioned SI diblock amount. , And the SI diblock amount is 40
It has been found that the adhesive residue phenomenon can be solved satisfactorily by setting the content to not more than the weight%, and the present invention has been completed.

In the present invention, the amount of the other components used is not particularly limited with respect to 100 parts by weight of the styrene-isoprene-styrene block copolymer. For example, 0 to about 150 parts by weight of a hydrocarbon-based tackifying resin, Softener 0-2
0 parts by weight and 0 to 5 parts by weight of an antioxidant are preferred.

The styrene-isoprene-styrene block copolymer of the present invention is not particularly limited, but its styrene content is preferably at least 15% by weight. As a product sold as such a styrene-isoprene-styrene block copolymer, Clayton D-1124 manufactured by Clayton Polymer Japan, JSR SIS5000, 5002, 5405 manufactured by JSR, and the like can be used.

Examples of the hydrocarbon-based tackifying resin include modified rosin-based resins such as xylene resin, rosin and polymerized rosin, hydrogenated rosin and rosin ester, and terpene-based resins such as terpene resin, terpene phenol resin and rosin phenol resin. Resins, aliphatic, aromatic and alicyclic petroleum resins, coumarone resins, styrene resins, alkylphenol resins, and the like.Examples of commercially available products include Picotack resin manufactured by Hercules Japan Can be mentioned.

Examples of the softening agent include paraffinic process oils and naphthenic oils. Among them, preferred are naphthenic oils, and commercially available products include Diana Process NM280 manufactured by Idemitsu Kosan Co., Ltd.

Examples of the antioxidant include N-phenyl-N'-isopropyl-p-phenylenediamine, tetrakis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)) methane and the like. be able to. Among them, preferred is tetrakis (methylene (3,5-di-tert-butyl-4).
-Hydroxyhydrocinnamate)) It is methane, and as a commercially available product, Irganox 1010 manufactured by Ciba Geigy can be used.

The pressure-sensitive adhesive composition of the present invention is prepared by mixing respective components at a mixing temperature of about 130 to 150 ° C. using a general-purpose rubber mixer such as a Labo Plastomill, a kneader, a Banbury mixer, and a roll. Can be manufactured.

When the pressure-sensitive adhesive composition of the present invention is used as a pressure-sensitive adhesive, a product such as a tape can be obtained by coating an appropriate substrate. The substrate is not particularly limited, and a substrate made of any material such as a synthetic resin film such as polyethylene, polypropylene, and polyvinyl chloride can be used.

In order to produce a product such as a tape using the pressure-sensitive adhesive composition of the present invention, the mixed pressure-sensitive adhesive composition is applied to a separator (about 30 μm) using a hot melt applicator (about 150 ° C.). Then, by transferring the pressure-sensitive adhesive with a separator to a substrate, a film with a pressure-sensitive adhesive having excellent adhesion to an adherend and having a surface on which no adhesive remains on the adherend can be obtained. .

[0019]

The present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited to these examples. Examples and Comparative Examples (Production of pressure-sensitive adhesive) As a styrene-isoprene-styrene block copolymer, Kraton D-1124, JSR
SIS5000, JSR SIS5002, JSR
Using SIS5405, Clayton D-1113, Clayton DKX406, Winterac 3520 (manufactured by Nippon Zeon) and JSR SIS5505, Picotac B (manufactured by Hercules Japan) as a tackifying resin, and Diana Process NM28 as a softening agent
0 (manufactured by Idemitsu Kosan Co., Ltd.) and Irganox 1010 (manufactured by Ciba Spatialty Chemicals) as an anti-aging agent. By using Laboplus Mill (manufactured by Toyo Seiki Co., Ltd.), the mixture was mixed at 150 ° C. and 30 rpm for 30 minutes to produce adhesive formulations A to H.

[0020]

[Table 1]

(Preparation of pressure-sensitive adhesive tape) The above-prepared pressure-sensitive adhesive composition was mixed for about 1 hour using a hot melt applicator.
After coating (approximately 30 μm) on the separator at 50 ° C., the pressure-sensitive adhesive with the separator was transferred to the pressure-sensitive adhesive-coated surface of the base PVC film by a roller and cured for one day. The following evaluation was performed using the prepared adhesive tape.

(Evaluation method) Evaluation was made according to JIS Z 023
The following items were performed in accordance with No. 7.・ Evaluation item: Adhesive strength 24 hours after application, target value 2.5 k
It was evaluated as gf / 25 mm or more, and it was confirmed that no adhesive remained. -Measuring method: Performed by a peeling test at 180 ° C.
Sample width: 25 mm. Opponent material: SUS304 plate is sandpaper (water resistant 280)
No.) was polished and degreased before use. Peeling speed: 300 ± 30 mm / min. Table 2 shows the evaluation results.

[0023]

[Table 2]

The pressure-sensitive adhesive comprising the pressure-sensitive adhesive composition of the present invention comprises:
The adhesive strength was sufficiently exhibited, and no adhesive residue was left.

[0025]

Since the pressure-sensitive adhesive composition of the present invention has the above-mentioned constitution, it is good for the environment, exhibits good adhesiveness to an adherend, and can be peeled again after joining. Since there is sometimes no adhesive residue, it is extremely useful for applications where adhesive residue such as medical tapes is to be eliminated.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J040 BA172 BA202 DB022 DK012 DM011 DN032 EB022 EB082 HB01 JB01 KA26 KA29 KA31 LA06 NA02 NA06 NA12 PA23

Claims (1)

[Claims] 1. A styrene-isoprene-styrene block copolymer, a hydrocarbon-based tackifying resin, a softening agent, and
A pressure-sensitive adhesive composition comprising an antioxidant, wherein the styrene-isoprene-styrene block copolymer has a styrene-isoprene diblock content ratio of all styrene-
A pressure-sensitive adhesive composition, wherein the content is 40% by weight or less in the isoprene-styrene block copolymer.