JPH0425988B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive composition that exhibits excellent adhesiveness even in the presence of water, and is useful in medical, agricultural, industrial, and various other fields. . Conventionally, oil-based rubber-based or acrylic-based polymers are generally used as adhesives for cellophane tape, vinyl tape, bandages, etc., but these do not adhere to wet surfaces and do not contain moisture. In this state, the adhesiveness decreases as the moisture content increases, and above a certain point, there is no adhesiveness at all. In addition, water-soluble adhesives such as starch glue, dextrin, polyvinyl alcohol, gelatin, etc. require an appropriate amount of moisture to exhibit adhesive strength, but the presence of more moisture than necessary will reduce adhesive properties.
It is known that adhesive strength is completely lost at extremely excessive moisture content. The present inventors have corrected the above-mentioned drawbacks of conventional adhesives, and have conducted extensive research into adhesive compositions that exhibit sufficiently excellent adhesive properties not only in the absence of moisture but also in the presence of moisture. As a result, the present invention was completed. That is, the present invention provides acrylic acid, methacrylic acid,
A monomer consisting of one or more selected from crotonic acid, maleic acid, fumaric acid, itaconic acid, and alkali metal salts, ammonium salts, and amine salts of these acids (hereinafter referred to as monomer (A)) )30
~90% by weight, and the general formula CH ₂ CX−COOR [however, X
is H or CH ₃ , R is CH ₂ CH ₂ OY or
CH ₂ CH ₂ CH ₂ OY (Y is H, CH ₃ or C ₂ H ₅ )] (hereinafter referred to as monomer (B)) ) 10 to 70
This is an adhesive composition comprising a copolymer obtained by polymerizing a monomer mixture with % by weight. As mentioned above, the present invention consists of a copolymer obtained by copolymerizing a mixture of monomer (A) and monomer (B), but the alkali metal salt in monomer (A) is acrylic. The monomer (B) is a sodium or potassium salt of acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, or itaconic acid, and the monomer (B) is a hydroxy or alkoxyalkyl acrylic salt as shown in the above general formula. acid or methacrylic acid ester, specifically 2-hydroxyethyl (meth)
Acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, etc. I can do it. The blending amounts of these monomers (A) and (B) are such that monomer (A) is
30 to 90% (weight%; the same applies hereinafter) preferably 40 to 60
%, monomer (B) is 10 to 70%, preferably 40 to 60%, and the copolymer obtained within the above range exhibits excellent adhesiveness regardless of the presence or absence of water. be. Monomer (A) is less than 30% (i.e. monomer (B) is 70%
%), the resulting pressure-sensitive adhesive composition will not have sufficient hydrophilicity and will not have sufficient tackiness in a state containing a large amount of water, which is the objective of the present invention. On the contrary, monomer (A) exceeds 90% (i.e. monomer (B)
(less than 10%), it becomes soluble in water and has insufficient adhesion in the presence of a large amount of water, making it impractical. In the present invention, other copolymerizable vinyl monomers such as vinyl acetate, acrylic ester, methacrylic ester, acrylonitrile, styrene are added to the mixture of monomers (A) and (B). etc. may be used together. In this case, the blending amount is (A),
(B) It is mixed in an amount of 30% or less of the monomer mixture and copolymerized. The method of polymerizing the monomer mixture may be any of general solution polymerization, emulsion polymerization, and suspension polymerization, and is not particularly limited. In addition, after polymerization, neutralizing agents (bases such as caustic soda, caustic potash, ammonia, etc., and amines such as ethylamine, triethanolamine, etc.) are added, solvent substitution, or divalent or higher metal ions (e.g., Ba, Ca, Zn, Mg, (A)l, Zr, Cu, Fe
etc.) may be used for crosslinking. The adhesive composition of the present invention has excellent adhesive properties even on surfaces wet with water, especially when the water content is 10%.
It has a good adhesive even when it contains the above.
The adhesive composition of the present invention can be used in a state without peeling by being mixed with the base of a tofu, other adhesive patch, bandage, etc. for medical purposes,
Also, for agricultural purposes, for spreading water-containing agricultural chemicals (e.g. insecticides, plant growth promoters, etc.) on sheets or tapes and attaching them to trees, etc., or for industrial and other uses, wet Adhesives for tapes and sheets that are attached to surfaces, additives to improve the initial adhesive strength (adhesive strength when wet with water) of rewet adhesives for wallpaper, gummed tape, labels, etc., and initial adhesives for emulsion adhesives. It can be used in many ways as an adhesive agent. Among these, in recent years, particularly in the medical field, there have been many studies on attempts to absorb drugs through the skin, and among these, there are many compositions that contain a large amount of water, and the adhesive composition of the present invention is one of them. The combination of these substances increases the adhesion to the skin and eliminates the need for further fixation with adhesive plasters, adhesive tapes, bandages, etc., which saves time and effort for treatment and eliminates inconvenience for the patient. In addition, re-wetting starch paste, polyvinyl alcohol, etc. are often used as the back layer of wallpaper, but when applying it to a wall or ceiling after wetting it with water, the initial adhesion strength (stairs where moisture still remains) (adhesion force) is weak,
It is usually necessary to hold it down for a while (until it dries). By blending the adhesive composition of the present invention into this rewetting adhesive, such troublesome pressing is no longer necessary, and work efficiency can be greatly improved and a good finished state can be maintained. The present invention will be explained below with reference to Examples and Comparative Examples. Example 1 A 5-pack reactor equipped with a stirrer, a thermometer, a condenser, a dropping funnel, and a nitrogen gas introduction tube was charged with
Charge 1,500 g of methanol and 1 g of AIBN (azobisisobutyronitrile), and after purging with nitrogen, raise the temperature to 60°C in a nitrogen atmosphere, and while maintaining this temperature, add 400 g of acrylic acid and 2-methoxyethyl acrylate.
600g of AIBN and 3g of AIBN were continuously added dropwise over 2 hours.
After completing the dropwise addition, keep it at 60℃ for 1 hour under stirring and cool it.
A pressure-sensitive adhesive composition of the present invention was obtained. Example 2 In the same reactor as used in Example 1 were added 1,750 g of deionized water, 90 g of acrylic acid, 60 g of 2-ethoxyethyl acrylate, and 1.5 g of ammonium persulfate.
After purging with nitrogen, the temperature was raised to 70℃ in a nitrogen atmosphere, and after 30 minutes, 90 g of acrylic acid, 60 g of 2-ethoxyethyl acrylate, and 1.5 g of ammonium persulfate were added.
Add g. This operation was further repeated three times every 30 minutes, and after the addition of the last monomer, the mixture was kept at 70°C for 1 hour and then cooled to obtain a pressure-sensitive adhesive composition of the present invention. Example 3 Into the same reactor used in Example 1, 1500 g of isopropanol (IPA) and 1 g of AIBN were charged.
After nitrogen substitution, the temperature was raised to 70° C. in a nitrogen atmosphere, and while maintaining this temperature, 300 g of methacrylic acid, 300 g of 3-methoxypropyl methacrylate, 150 g of butyl acrylate, and 3 g of AIBN were continuously added dropwise over 2 hours. After the dropwise addition was completed, the temperature was kept at 70°C for 1 hour with stirring, and 750g of IPA was expelled under reduced pressure. After cooling, add 220 g of triethanolamine and 400 g of 10% caustic soda.
, then expel IPA under reduced pressure, and continue expelling while adding water to completely replace IPA with water.
The composition was adjusted to 30% to obtain a composition of the present invention. Example 4 Deionized water was added to the same reactor used in Example 1.
1750g, emulsifier (Levenol manufactured by Kao Atlas)
WZ) 4g, potassium persulfate 0.2g, itaconic acid 45
g, 60 g of 2-methoxyethyl acrylate, and 45 g of vinyl acetate were charged, and after nitrogen substitution, the temperature was raised to 70°C in a nitrogen atmosphere, and after 30 minutes, 45 g of itaconic acid, 2
- 60 g of methoxyethyl acrylate and 45 g of vinyl acetate were added. Repeat this operation three more times every 30 minutes for 1 hour after adding the last monomer.
C. and then cooled to obtain a pressure-sensitive adhesive composition of the present invention. Examples 5, 6 and Comparative Example 1 The adhesive compositions obtained in Examples 2 and 3 were used as part of the ingredients to produce a tofu agent, and the resulting tofu agent (Examples 5 and 6) and The adhesion to the skin (comparison by feel) was investigated for a cloth agent (Comparative Example 1) obtained without using the adhesive composition according to the present invention. The results are shown in Table 1, and the preparation of the tofu agent was carried out as follows. That is, first, gelatin was dissolved in warm water at 40 to 60°C, and zinc oxide was further mixed therein. Separately, sodium polyacrylate was dispersed in glycerin, thoroughly kneaded with the above mixture while heating to 40 to 60°C, and then added to the polymer obtained in Example 2 with triethanolamine 447
g (polymer neutralized product) or Example 3
The polymers obtained in step 1 are mixed, then cooled to 40°C and kneaded carefully so as not to evaporate the medicinal agents methyl salicylate, camphor and menthol. It was spread evenly to a thickness of , and a polyethylene film was attached to the surface to make a cloth agent.

[Table] Examples 7 to 10 The adhesive compositions obtained in Examples 1 to 4 were applied to a polyester film to a thickness of 25μ (dry), and
After drying at ℃ for 5 minutes, adhesive strength and adhesive strength were measured in the presence of moisture. The results are shown in Table 2 in comparison with a commercially available vinyl tape (Comparative Example 2). In addition, the measurement of adhesive force and adhesive force was based on the following. (1) Adhesive strength: Soak the plywood board in water for 1 hour, take it out, wipe the moisture on the surface with a cloth, and immediately attach adhesive tape (25 mm width).
Peel at 90°C (300mm/min). (2) Adhesiveness: Wet the adhesive tape and your finger with water, check the tack by touching it with your finger, and give a value of 3 to 0 in descending order of tackiness. (However, 0 indicates no tact at all)

[Table] Examples 11 to 14 and Comparative Examples 3 and 4 Each of the pressure-sensitive adhesive compositions of Examples 1 to 4 was subjected to the following treatments. (However, Example 3 was not treated) (1) 100 g of the composition of Example 1 was neutralized with 30 g of triethanolamine (hereinafter referred to as composition (A)) (2) Composition of Example 2 Neutralize 100g of the product with 20g of triethanolamine and 40g of 10% NaOH (hereinafter referred to as composition (B)) (3) Composition of Example 3...untreated (hereinafter referred to as composition
(referred to as composition (C)) (4) Neutralize 100 g of the composition of Example 4 with 15 g of triethanolamine and 20 g of 10% NaOH (hereinafter referred to as composition (D)) Next, the composition obtained above ( The following tests were conducted with or without A) to (D). That is, (i) PVA (polyvinyl alcohol...Nippon Gosei Co., Ltd. trade name Gohsenol) alone (Comparative Example 3) (ii) PVA with 10% composition (A) added (Example
11) (iii) PVA with 10% composition (B) added (Example
12) (iv) Starch powder (Niden Co., Ltd. trade name: Biostarch) alone (Comparative Example 4) (v) Starch powder with 10% composition (C) added (Example 13) ( vi) 10% composition (D) added to starch powder (Example 14) The above was applied to a thickness of 25μ on high-quality paper,
After drying at 100℃ for 5 minutes, soak the surface of the lake with 100% moisture and place a piece of wood vertically (adhesive area 25mm x 25mm).
A load of 50 g was hung on the wooden piece parallel to the adhesive surface, and the degree of adhesion was measured by the falling time (seconds within a maximum of 10 seconds) of the wooden piece. The results are shown in Table 3.

【table】

Claims (1)

[Scope of Claims] 1 Consists of one or more selected from acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and alkali metal salts, ammonium salts, and amine salts of these acids. 30 to 90% by weight of monomer, general formula CH ₂ CX-COOR [where X is H or CH ₃ , R is CH ₂ CH ₂ OY or
CH ₂ CH ₂ CH ₂ OY (Y is either H, CH ₃ or C ₂ H ₅ ) A pressure-sensitive adhesive composition comprising a copolymer obtained by polymerizing a polymer mixture.