JPH07100780B2 - Adhesive sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive sheet, and more specifically, a polyurethane-based adhesive sheet.
The present invention relates to a pressure-sensitive adhesive sheet which is obtained by directly and firmly adhering a pressure-sensitive adhesive made of a diene-based copolymer on a base material sheet made of a polyvinyl chloride graft copolymer, and which can be suitably used as a patch, for example.

Conventional technology Adhesive sheets are used in various applications, for example,
BACKGROUND OF THE INVENTION Patches prepared by laminating an adhesive containing a drug such as a skin stimulant or an anti-inflammatory analgesic on a base sheet are used for medical purposes. In such a patch, for example, JP-A
As described in JP-A No. 54-138124, not only does it have good adhesiveness and elasticity when the patch is applied to the skin, but also does not cause irritation to the skin at the time of peeling and can be easily peeled off. As the adhesive, a diene-based copolymer, in particular,
Diene block copolymers are known to be suitable.

On the other hand, in the patch as described above, as the base sheet, a vinyl chloride resin which is soft and conforms to the skin is preferable, but on the other hand, the vinyl chloride resin sheet is a diene-based adhesive as an adhesive. Poor affinity with block copolymer, especially in patch, since diene block copolymer as an adhesive contains higher fatty acid and fluid paraffin as a plasticizer together with the drug, vinyl chloride-based Poor affinity with resin base sheet. As a result, when a pressure-sensitive adhesive composed of a diene-based block copolymer is simply applied directly onto a vinyl chloride-based resin base sheet to form a patch, there is a problem in that the adhesiveness of the pressure-sensitive adhesive to the base sheet is poor.

Therefore, it is possible to increase the affinity for the diene block copolymer by subjecting the vinyl chloride resin sheet to an appropriate primer treatment. However, according to this method, as the number of steps increases, However, the manufacturing cost must be high.

In order to solve such a problem, for example, JP-A-62-1279
No. 83, in addition to ethylene-vinyl acetate copolymer and thermoplastic polyurethane in polyvinyl chloride, styrene-
A resin composition obtained by mixing an ethylene-butylene-styrene block copolymer is molded into a base sheet, and a pressure sensitive adhesive comprising a styrene-diene-styrene block copolymer is laminated and adhered on the base sheet. Then, the method of manufacturing an adhesive sheet is proposed.

However, according to this method, the physical properties of the base sheet are deteriorated with time, such as the agent in the pressure-sensitive adhesive migrating into the base sheet, and the strength of the base sheet is impaired. -Ethylene-butylene-styrene block copolymer is not necessarily compatible, at the stage of processing the resin composition into a substrate sheet, the copolymer is difficult to gel, the resulting substrate sheet has a hole To do. The base sheet containing the styrene-ethylene-butylene-styrene block copolymer has rubber elasticity due to this copolymer, and the smoothness and suppleness inherent in the soft vinyl chloride resin are lost. Further, it is desired that the base sheet has transparency, but the base sheet containing the styrene-ethylene-butylene-styrene block copolymer is opaque.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems, wherein ethylene-vinyl acetate-
An adhesive consisting of a diene block copolymer is directly and firmly adhered and laminated on a base material sheet consisting of a polyurethane-polyvinyl chloride graft copolymer containing a carbon monoxide copolymer, resulting in a feeling and flexibility. Good sex, for example
It is an object to provide an adhesive sheet that can be suitably used as a patch.

Means for Solving the Problems The pressure-sensitive adhesive sheet according to the present invention comprises an ethylene-vinyl acetate-carbon monoxide copolymer 1 as a tackifying resin for 100 parts by weight of a polyurethane-polyvinyl chloride graft copolymer.
It is characterized in that a pressure-sensitive adhesive made of a styrene-diene-styrene block copolymer is laminated and adhered on a base material sheet made of a resin composition containing about 60 parts by weight.

In the present invention, the polyurethane-polyvinyl chloride graft copolymer refers to JP-A-58-42611 and JP-A-58-4.
As described in JP 0312, it is a polyvinyl chloride graft polyurethane copolymer obtained by dissolving a thermoplastic polyurethane in a vinyl chloride monomer and subjecting this to suspension polymerization of the vinyl chloride monomer.

The substrate sheet used in the present invention is a polyurethane-polyvinyl chloride graft copolymer 100 parts by weight, a resin composition containing 1-60 parts by weight of ethylene-vinyl acetate-carbon monoxide copolymer as a tackifying resin. For example, it can be obtained by forming a sheet by a calendar method.

The ethylene-vinyl acetate-carbon monoxide copolymer used as the tackifying resin in the present invention is already known, and for example, those commercially available as "Elvalloy" from Mitsui-Dyupon Polychemical Co., Ltd. are suitable. Can be used for.

When the blending amount of the ethylene-vinyl acetate-carbon monoxide copolymer is less than 1 part by weight with respect to 100 parts by weight of the polyurethane-polyvinyl chloride graft copolymer, the adhesive property between the base sheet and the pressure-sensitive adhesive is If not improved, on the other hand, when it exceeds 60 parts by weight, the ethylene-vinyl acetate-carbon monoxide copolymer has a low melt viscosity, gels faster than the polyurethane-polyvinyl chloride graft copolymer, The raw material resin composition is liable to form powdery gel during production. Particularly, in the present invention, the ethylene-vinyl acetate-carbon monoxide copolymer is preferably used in the range of 5 to 50 parts by weight with respect to 100 parts by weight of the polyurethane-polyvinyl chloride graft copolymer.

Thus, according to the present invention, as the tackifying resin in the substrate sheet, a predetermined amount of ethylene-vinyl acetate-
By using the carbon monoxide copolymer, it is possible to obtain a uniform base sheet having strong adhesion to the pressure-sensitive adhesive layer described later, and in the obtained pressure-sensitive adhesive sheet, the tackifying resin is a pressure-sensitive adhesive with time. For example, it is possible to obtain a medicated patch which is excellent in application feeling without shifting to a layer.

Polyurethane used as a substrate sheet in the present invention
The polyvinyl chloride graft copolymer sheet can be a non-plastic soft sheet containing no plasticizer because the polyurethane component functions as a plasticizer, but if necessary, the base sheet may contain a plasticizer. May be. But,
When a polyurethane-polyvinyl chloride graft copolymer contains a large amount of a plasticizer together with a tackifying resin, stickiness occurs during sheet production, which makes sheet production difficult, and the plasticizer and tackifying resin may not adhere to the sheet surface. The above-mentioned bloom, bleeding, etc. occur, and in the obtained pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer also becomes sticky with time. Therefore,
The plasticizer is preferably used in the range of 20 parts by weight or less with respect to 100 parts by weight of the polyurethane-polyvinyl chloride graft copolymer. As the plasticizer, a high molecular weight polyester plasticizer is suitable.

In the present invention, the polyurethane-polyvinyl chloride graft copolymer sheet preferably has a thickness in the range of 50 to 150 μm so as not to cause a feeling of strangeness when applied to the skin. When it is too thin, the strength is not practically sufficient, while when it is too thick, it is easily peeled off after sticking to the skin, which is not preferable.

Furthermore, in the present invention, the polyurethane-polyvinyl chloride graft copolymer sheet preferably contains a suitable amount of a so-called non-toxic stabilizer. Suitable examples of such stabilizers include, for example, calcium-zinc stabilizers which are already well known as stabilizers for vinyl chloride resins, but are not particularly limited to the above as long as they are non-toxic. It is not something that will be done.

Further, the polyurethane-polyvinyl chloride graft copolymer may contain a filler. The filler is, for example,
When the base material sheet is a roll, its developability is enhanced.
That is, it is effective in improving the blocking resistance. The filler is usually added in an amount of 30 parts by weight or less with respect to 100 parts by weight of the polyurethane-polyvinyl chloride graft copolymer.

Further, in the present invention, polyvinyl chloride may be used together with the polyurethane-polyvinyl chloride graft copolymer. Polyvinyl chloride has an average degree of polymerization of 400-200
It is preferably 0, particularly in the range of 700 to 1400. However, when blended in an excessive amount, the compatibility with the skin is deteriorated. Therefore, the blending amount is preferably 30 parts by weight or less per 100 parts by weight of the polyurethane-polyvinyl chloride graft copolymer.

In the pressure-sensitive adhesive sheet according to the present invention, a layer of styrene-diene-styrene block copolymer as a pressure-sensitive adhesive is directly laminated and adhered on the base sheet. According to the invention,
Since the base material sheet comprising the above resin composition contains the above-mentioned tackifying resin, it has an excellent affinity for styrene-ethylene-butylene-styrene block copolymer,
When a pressure sensitive adhesive composed of a styrene-diene-styrene copolymer is applied thereon, high adhesiveness can be obtained during that time.

In the present invention, styrene-diene-constituting the pressure-sensitive adhesive
Specific examples of the styrene block copolymer include a styrene-butadiene-styrene block copolymer and a styrene-isoprene-styrene block copolymer. These styrene-diene-styrene block copolymers may be used alone or as a mixture as a pressure-sensitive adhesive, or together with these block copolymers, a plasticizer, a tackifying resin other than the above, a filler, an antioxidant and the like. It may be used as a composition containing. Further, it may contain a necessary drug as in the case of the above-mentioned attached drug.

Such a styrene-diene-styrene block copolymer is already known as described in detail in, for example, Japanese Patent Laid-Open No. 138124/1979 mentioned above, and A is a glass-like or hard non-polymer made of styrene. When the block is an elastic thermoplastic polymer and B is the block of an elastic polymer of a conjugated diene such as butadiene or isoprene, AB
In the block copolymer having the structure of -A, the block A accounts for 10 to 50% by weight of the total weight of the polymer. Such a styrene-butadiene-styrene block copolymer is used as Califlex TR-1101, TR-1102, etc., and a styrene-isoprene-styrene block copolymer is Califlex TR-1107 (all manufactured by Shell Chemical Co., Ltd.). It is commercially available as and can be obtained.

The pressure-sensitive adhesive sheet according to the present invention is a styrene-diene-containing resin composition obtained by molding the resin composition into a base material sheet by an appropriate method such as calendering or extrusion molding, and optionally containing a drug and other additives. It can be obtained by melt coating a styrene block copolymer.

EFFECTS OF THE INVENTION As described above, according to the pressure-sensitive adhesive sheet of the present invention, the base sheet is made of the polyurethane-polyvinyl chloride graft copolymer containing the ethylene-vinyl acetate-carbon monoxide copolymer as the tackifying resin. Therefore, such a base sheet has not only excellent texture and flexibility, but also styrene-
Since it has excellent adhesiveness with a diene-styrene block copolymer, the styrene-diene-styrene block copolymer as a pressure-sensitive adhesive is directly and firmly adhered to the base sheet, and is suitable as a patch, for example. Can be used for

Furthermore, according to the pressure-sensitive adhesive sheet of the present invention, the ethylene-vinyl acetate-carbon monoxide copolymer used as the tackifying resin has excellent transparency and the processing temperature is low, so that the base sheet also undergoes thermal discoloration during production. It is possible to obtain a substantially transparent substrate sheet that does not occur.

Further, as a preferred embodiment according to the present invention, when the base material sheet does not contain a plasticizer, there is no component that migrates from the base material sheet to the pressure-sensitive adhesive, while the base material sheet is made of styrene-
Since it does not contain an ethylene-butylene-styrene block copolymer, the drug in the pressure-sensitive adhesive does not migrate into the base sheet, and thus the adhesiveness of the pressure-sensitive adhesive sheet is maintained over a long period of time, and the base sheet The physical properties of the base sheet are not deteriorated with time, such as the decrease in strength, and the durability is excellent. Further, when used as a patch, the skin irritation is small.

In addition, according to the present invention, since the resin composition does not contain a styrene-ethylene-butylene-styrene block copolymer, even when it is processed into a base material sheet, no perforation occurs and it is obtained. The base sheet is transparent.

EXAMPLES The present invention will be described below with reference to examples. In the following, parts mean parts by weight.

Examples As shown in Table 1, a polyurethane-polyvinyl chloride graft copolymer (Dominus K-800C manufactured by Tosoh Corporation) was kneaded with a tackifying resin, a stabilizer, and optionally polyvinyl chloride or a plasticizer. Thickness 130 μm
Was used as the base material sheet.

A styrene-isoprene-styrene block copolymer (Calibrex TR
-1107) was melt-coated to a thickness of 100 μm to prepare an adhesive sheet.

With respect to these pressure-sensitive adhesive sheets, the adhesiveness between the base sheet and the pressure-sensitive adhesive layer and roll processability were examined as follows.
The results are shown in Table 1.

Adhesiveness between base material sheet and pressure-sensitive adhesive A pressure-sensitive adhesive sheet cut into a width of 25 mm and a length of 5 cm was packaged and sealed with an aluminum foil and left at 40 ° C for 2 weeks. Then, the pressure-sensitive adhesive sheet was taken out, adhered to a bakelite plate, left for 1 hour, and then subjected to a 180 ° peeling test at room temperature at a tensile speed of 200 mm / min. The evaluation was as follows. ○ indicates that the adhesive does not peel off from the base sheet, Δ indicates that the adhesive peels off a part of the base sheet, but there is no particular problem in practice, and x indicates that the adhesive almost completely peels off the base sheet. Show.

Roll processability Two 12-inch rolls heated to about 175 ° C are used, the distance between the rolls is 0.2 mm, and 200 g of compound is kneaded, and the lubricity with the roll (peelability), gelation (bank shape) and plate Out was evaluated comprehensively. The evaluation was as follows. A: Good, Δ: Sliding property is slightly reduced, but practically no problem. ×: Sliding property is poor, and the film is not easily peeled off from the metal roll and cannot be processed.

Claims (1)

[Claims] 1. A base sheet comprising a resin composition containing 1 to 60 parts by weight of an ethylene-vinyl acetate-carbon monoxide copolymer as a tackifying resin with respect to 100 parts by weight of a polyurethane-polyvinyl chloride graft copolymer. A pressure-sensitive adhesive sheet, characterized in that a pressure-sensitive adhesive comprising a styrene-diene-styrene block copolymer is laminated and adhered thereon.