JP2563846B2 - Adhesive sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive sheet, and more specifically, a pressure-sensitive adhesive made of a diene-based copolymer is directly and firmly adhered to a base sheet, and there is no dimensional change. For example, it relates to an adhesive sheet that can be suitably used as a patch.

Conventional technology Adhesive sheets are used for various purposes. For example, a patch containing an adhesive containing a drug such as a skin stimulant or an anti-inflammatory analgesic on a base sheet is used for medical purposes. Has been done. In such a patch, for example, as described in JP-A-54-138124, not only does it have good adhesiveness and elasticity when the patch is applied to the skin, but also the skin during peeling. It is known that a diene-based copolymer, particularly a diene-based block copolymer, is particularly suitable as the pressure-sensitive adhesive because it can be easily peeled off without giving any irritation.

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, but with this method, as the number of steps increases, However, the manufacturing cost must be high.

In order to solve such a problem, for example, Japanese Patent Laid-Open No. 1-22
In Japanese Patent No. 3186, as shown in FIG.
A base sheet 1 is formed of a resin composition containing a polyvinyl chloride graft copolymer and an ethylene-vinyl acetate copolymer, and containing no plasticizer, and a styrene-diene-styrene block copolymer is formed on the base sheet 1. A pressure-sensitive adhesive sheet 4 has been proposed in which the pressure-sensitive adhesive 2 is laminated and adhered, and the release paper 3 is further laminated thereon. As shown in FIG. 2, when the adhesive sheet 4 has the release paper 3 in this way, the release paper is
A cut 5 is usually made across the pressure-sensitive adhesive sheet so that it can be easily peeled off.

However, in the production of the above-mentioned pressure-sensitive adhesive sheet, the base material film swells with time, causing a dimensional change, thus forming voids in the breaks of the release paper, impairing the appearance, and significantly lowering the product value. .

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that salicylic acid ester derivatives contained as a drug in an adhesive swell a polyurethane-polyvinyl chloride polymer. It was also determined that the styrene-ethylene-butylene-styrene block copolymer contained in the base sheet was swollen by the fluid paraffin in the pressure-sensitive adhesive, and the salicylate derivative was previously prepared in the base sheet. The present invention has been accomplished by finding that the swelling of the base material sheet with time can be effectively prevented by blending a predetermined amount of the above-mentioned and fluid paraffin in a predetermined amount.

That is, in the present invention, a pressure-sensitive adhesive comprising a diene block copolymer is directly and strongly laminated and adhered on a base material sheet having excellent feeling and flexibility, and further, it can be stored for a long period of time. An object of the present invention is to provide a pressure-sensitive adhesive sheet that does not substantially change the dimensions of the base sheet.

Means for Solving the Problems The pressure-sensitive adhesive sheet according to the present invention comprises (a) 99-1% by weight of a polyurethane-polyvinyl chloride graft copolymer, polyvinyl chloride, a vinyl chloride-vinyl acetate copolymer, and a vinyl chloride-ethylene copolymer. At least 1 selected from polymers and vinyl chloride-propylene copolymers
100 parts by weight of a base resin composed of 1 to 99% by weight of a polyvinyl chloride-based polymer as a seed, (b) 1 to 20 parts by weight of styrene-ethylene-butylene-styrene block copolymer, and (c) ethylene- A group consisting of a resin composition containing 1 to 50 parts by weight of vinyl acetate copolymer resin, and (d) 1 to 20 parts by weight of salicylate, and / or (e) 0.5 to 6 parts by weight of liquid paraffin. It is characterized in that a pressure sensitive adhesive comprising a styrene-diene-styrene block copolymer is laminated and adhered on a material sheet.

In the present invention, the base resin is a polyurethane-polyvinyl chloride graft copolymer 99 to 1% by weight and polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer and vinyl chloride-propylene copolymer. At least one polyvinyl chloride polymer selected from polymers 1
~ 99% by weight.

As the above-mentioned polyurethane-polyvinyl chloride graft copolymer, for example, one commercially available as "Dominus" from Tosoh Corporation can be preferably used. Although the degree of polymerization of polyvinyl chloride and the composition of polyurethane in the copolymer may be variously changed, in the present invention, JI
SA hardness 100-70, tensile strength 250-450kg / cm ² , elongation 200-600
% Copolymers are preferably used.

In the present invention, the polyvinyl chloride-based polymer is at least one selected from polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer and vinyl chloride-propylene copolymer, Although a mixture of these is included, among these, polyvinyl chloride having an average degree of polymerization of 400 to 2000, particularly 700 to 1400 is preferably used.

In the present invention, the base resin is the above polyurethane-
The polyvinyl chloride graft copolymer comprises 99 to 1% by weight, preferably 90 to 10% by weight, and the polyvinyl chloride polymer 1 to 99% by weight, preferably 10 to 90% by weight.

In the present invention, the resin composition constituting the base sheet is 100 parts by weight of the base resin as described above, 1-20 parts by weight of styrene-ethylene-butylene-styrene block copolymer and ethylene as a tackifying resin. 1 to 50 parts by weight of vinyl acetate copolymer resin, and 1 to 20 parts by weight of salicylate and / or 0.5 to 6 parts by weight of liquid paraffin.

In the above resin composition, the vinyl chloride polymer or the polyurethane-polyvinyl chloride graft copolymer gives its moldability, in particular, the fluidity under heating necessary for calendering and extrusion, as well as the substrate. Gives the sheet the required strength.

The styrene-ethylene-butylene-styrene block copolymer is used as a tackifying resin that gives the base sheet an affinity for the pressure-sensitive adhesive layer. Such a styrene-ethylene-butylene-styrene block copolymer is contained in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the base resin.

As the ethylene-vinyl acetate copolymer, one having a vinyl acetate content of 5 to 85% by weight is usually used.
In order that the resin composition has excellent calender processability, one having a vinyl acetate content of 45% by weight or more is preferably used. It should be noted that the ethylene-vinyl acetate copolymer includes an ethylene-vinyl acetate vinyl chloride copolymer.

The ethylene-vinyl acetate copolymer gives metal slidability when the resin composition is heat-formed into a base sheet, and also gives flexibility to the obtained base sheet, and further, styrene constituting a pressure-sensitive adhesive. -Provides a high affinity for diene-styrene block copolymers.

In the resin composition, for 100 parts by weight of the base resin,
When the blending amount of the ethylene-vinyl acetate copolymer is less than 1 part by weight, the above effect cannot be sufficiently obtained,
It is inferior in both moldability and affinity for styrene-diene-styrene block copolymers. On the other hand,
When the amount exceeds 50 parts by weight, the obtained base sheet has excessive elasticity and, for example, when used as a patch, the conformability to the skin becomes poor. In addition, the resin composition is likely to soften at high temperatures, resulting in poor processability.

Thus, the pressure-sensitive adhesive sheet according to the present invention contains the styrene-ethylene-butylene-styrene block copolymer and the ethylene-vinyl acetate copolymer resin together with the base resin. Among these, elastic polymers include polyurethane-polyvinyl chloride graft copolymer, styrene-ethylene-
Butylene-styrene block copolymer and ethylene-vinyl acetate copolymer resin. However, the ethylene-vinyl acetate copolymer resin has a large thermochromic property, and if it is blended in a large amount, it imparts excessive tackiness to the base sheet, resulting in poor lubricity, while styrene-ethylene-butylene-styrene resin is used. Since the block copolymer has strong rubber elasticity, it is not preferable to add too much of it.

Therefore, according to the present invention, as described above, the amount of styrene-ethylene-butylene-styrene block copolymer in the base sheet is 1 to 20 parts by weight, and the amount of ethylene-vinyl acetate copolymer resin is 1 to 50. In parts by weight, the flexibility of the base sheet is basically designed by the compounding ratio of the plasticizer and the polyurethane-polyvinyl chloride graft copolymer while imparting the above-mentioned desirable properties to the base sheet. From such a viewpoint, in the present invention, the base resin is preferably polyurethane-polyvinyl chloride graft copolymer 10 to 90% by weight and polyvinyl chloride polymer 90 to.
It consists of 10% by weight.

In the present invention, the substrate sheet further contains salicylic acid ester and / or fluid paraffin. When the amount of the salicylic acid ester to be added is too large, the base material sheet is yellowed during the production of the base material sheet, so that the content is 0.5 to 25 parts by weight, preferably 1 to 100 parts by weight of the base resin. It is in the range of 20 parts by weight.

Usually, methyl salicylate or ethyl glycol salicylate (monoester) is preferably used as the salicylic acid ester. These may be used alone or as a mixture. Although salicylic acid esters other than those mentioned above may be used in the patch, in the present invention, such various salicylic acid esters are also used.

On the other hand, the fluid paraffin imparts lubricity to the resin composition,
When blended in an excessively large amount, the resin composition is imparted with excessive lubricity to cause unevenness and pinholes on the surface of the obtained base sheet, and the compatibility with polyvinyl chloride is not always good, and There is a risk of bleeding, so it is used in the range of 0.5 to 6 parts by weight, preferably 0.5 to 5 parts by weight.

Particularly, in the present invention, it is preferable that the substrate sheet contains both salicylate and fluid paraffin.

Further, according to the present invention, the base sheet may optionally contain a plasticizer. As such a plasticizer,
A relatively high molecular weight polyester plasticizer is preferably used. However, when contained in an excessively large amount, the plasticizer migrates into the pressure-sensitive adhesive layer to reduce the pressure-sensitive adhesive force or change the quality of the pressure-sensitive adhesive layer, making it difficult to practically use as a pressure-sensitive adhesive sheet for a patch. . Therefore, in the present invention, the compounding amount of the plasticizer is in the range of 30 parts by weight or less, preferably 20 parts by weight or less, relative to 100 parts by weight of the base resin.

Thus, even when the base sheet contains a plasticizer, the plasticizer has a high molecular weight, and since the compounding amount is small, it hardly affects the adhesive material, Therefore, the adhesive strength does not decrease with time. On the other hand, by blending the plasticizer into the base material sheet, the polyurethane-polyvinyl chloride graft copolymer in the base material sheet can be reduced, thus improving the fluidity of the resin composition, It is possible to obtain a base sheet which is free from heat discoloration and has excellent transparency.

In the present invention, the thickness of the substrate sheet is appropriately selected depending on the application, but is usually 0.05 to 0.20 mm.

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 present invention, the base material sheet comprising the above resin composition contains a styrene-ethylene-butylene-styrene block copolymer and has excellent affinity for the styrene-diene-styrene copolymer. When a pressure-sensitive adhesive composed of a styrene-diene-styrene copolymer is applied, high adhesiveness can be obtained during that time.

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

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 obtained by molding the resin composition into a sheet, melt-coating a styrene-diene-styrene block copolymer containing a drug and other additives as necessary, and further releasing the release paper. Can be obtained by sticking.

EFFECTS OF THE INVENTION As described above, according to the pressure-sensitive adhesive sheet of the present invention, the base material sheet further comprises a base resin made of a mixture of a polyurethane-polyvinyl chloride graft copolymer and a polyvinyl chloride-based polymer, and a tackifying resin. As comprising an ethylene-vinyl acetate copolymer and a resin composition containing a styrene-ethylene-butylene-styrene copolymer, excellent in feel and flexibility, further, styrene-diene-styrene block copolymer Since the styrene-diene-styrene block copolymer as a pressure-sensitive adhesive is directly and firmly adhered to the base material sheet, it can be suitably used as a patch, for example.

Furthermore, according to the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive also contains a salicylic acid ester derivative and a fluid paraffin which are contained in a base material sheet. As a result of the transfer to the material sheet being suppressed, the dimension of the substrate sheet does not change even if the substrate sheet is left for a long period of time after being coated with the adhesive.

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

Example As shown in Table 1, a polyurethane-polyvinyl chloride graft copolymer, polyvinyl chloride having an average degree of polymerization of 800,
Ethylene-vinyl acetate copolymer, styrene-ethylene-
A butylene-styrene block copolymer, a salicylic acid ester derivative, a fluid paraffin, a stabilizer, and a plasticizer, if necessary, were mixed and calendered into a base sheet having a thickness of 130 μm.

A styrene-isoprene-styrene block copolymer was melt-coated to a thickness of 100 μm as an adhesive on the obtained base sheet, and then punched with a 10 cm square dumbbell. Using this as a sample, the following evaluation test was performed. The results are shown in Table 1.

Swellability of adhesive sheet After sealing the sample in a bag made of aluminum foil and leaving it in a gear oven at 50 ° C for 1 day, determine the vertical and horizontal areas of the film and divide by the original area. The swelling ratio was calculated. The results are shown in Table 1. When the swelling ratio is 2.9% or less, as described above, no voids are formed between the cuts of the release paper, but when it exceeds 2.9%, voids are formed between the cuts of the release paper.

Adhesiveness The sample was sealed in an aluminum bag and left in a gear oven at 50 ° C for 1 day, then cut into a width of 25 mm and a length of 10 cm, which was attached to a bakelite plate and left for 10 minutes, then 200 mm A 180 ° peeling peeling test was performed at / min to examine the adhesive residue on the Bakelite plate. The results are shown in Table 1. ○ indicates no adhesive residue, △ indicates 1 to 5 adhesive residue
%, X means that the adhesive residue exceeds 5%.

Roll processability Using a 12-inch roll heated to about 175 ℃, the distance between the rolls is 0.2 mm, compound 200g is kneaded for 30 minutes,
Lubricity with roll (peelability), gelation (bank shape),
The plateout was evaluated comprehensively. The evaluation was as follows. ○: Good, △: Roll lubricity is slightly strong, but practically
There is no particular problem, and x indicates that the roll has strong slipperiness and cannot be formed into a sheet.

[Brief description of drawings]

FIG. 1 is a sectional view showing an adhesive sheet provided with a release paper according to the present invention, and FIG. 2 is a plan view thereof. 1 ... Base material sheet, 2 ... Adhesive, 3 ... Release paper, 4 ...
… Adhesive sheets, 5 …… breaks.

Claims (3)

(57) [Claims] (A) 99-1% by weight of a polyurethane-polyvinyl chloride graft copolymer and polyvinyl chloride, a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-ethylene copolymer and a vinyl chloride-propylene copolymer. 1 to 99% by weight of at least one polyvinyl chloride polymer selected from coalescence
100 parts by weight of the base resin consisting of (b) 1 to 20 parts by weight of styrene-ethylene-butylene-styrene block copolymer and (c) 1 to 50 parts by weight of ethylene-vinyl acetate copolymer resin. Styrene-diene-styrene block copolymer on a base sheet made of a resin composition containing (d) 1 to 20 parts by weight of salicylic acid ester and / or (e) 0.5 to 6 parts by weight of fluid paraffin. A pressure-sensitive adhesive sheet, comprising: a pressure-sensitive adhesive comprising: 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the salicylic acid ester is methyl salicylate or ethylene glycol salicylate. 3. The base resin comprises 10 to 90% by weight of a polyurethane-polyvinyl chloride graft copolymer and 90 to 10% by weight of a polyvinyl chloride polymer.
The pressure-sensitive adhesive sheet according to item.