JPH0770534A - Water-soluble pressure-sensitive adhesive resin - Google Patents

Abstract

PURPOSE:To obtain a water-soluble pressure-sensitive adhesive resin excellent in adhesion, and dissociative properties and releasability in the presence of water by using as the main component a copolymer prepd. from a plurality of specific compds. as the indispensable monomers and setting the glass transition temperature thereof at a predetermined value. CONSTITUTION:A water-soluble pressure-sensitive adhesive resin has a glass transition temperature of -50 to 20 deg.C and comprises as the main component a copolymer prepd. from an amino group-contg. (meth)acrylate, (meth)acrylamide or vinyl ether of the formula (wherein R<1> is H or CH3; R<2> and R<3> are each H or 1-5C alkyl; n is 1 to 5; and X is an ester, amide or ether bond), and/or a quaternary salt thereof (e.g. N,N-dimethylaminoethyl acrylate), and a vinyl amide compd. of the formula: CH2=CHNHCOR<4> (wherein R<4> is R<1>) as the indispensable monomers, the total amt. of which is 50 to 100wt.% based on all monomers.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel water-soluble adhesive resin. These have particularly good adhesion,
In addition, it can exhibit excellent disaggregation and peeling properties in the presence of water. For industrial products such as corrugated cardboard tape, gum tape, courier and parcel address stickers and labels, soldering mask tape, etc., liquid glue, vinyl tape and other household items, and hair removal tape, sanitary napkins, etc. The present invention relates to an adhesive tape / label for hygiene products, an adhesive resin used in a medical preparation for oral mucosa, a preparation for percutaneous absorption, and the like, and a water-soluble adhesive resin which is safe in human skin and body.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesives used for pressure-sensitive adhesive tapes and labels as household and industrial products are mainly natural rubber-based pressure-sensitive adhesives and styrene-butadiene rubber, isobutylene rubber and other synthetic rubber-based pressure-sensitive adhesives. (Reference: Ken Ibouchi, Kimie Komatsu, Yasuaki Kitazaki, Ed .: Adhesive Utilization Note, Industrial Research Committee, (August 1989)). But,
They become less tacky in humid places. Further, since these pressure-sensitive adhesives are hydrophobic, they are poor in disaggregation and peeling properties in the presence of water.

In recent years, several methods have been proposed to remedy these drawbacks. For example, JP-A-5-98
221 proposes a hydrophilic pressure-sensitive adhesive composition in which a hydrophilic natural polymer is mixed with a substance mainly containing glycerin as a substance for imparting tackiness. The power is weak. Recently, a pressure-sensitive adhesive using a copolymer of acrylamide or methacrylamide has been disclosed, but this is hydrolyzable under acidic or alkaline conditions and is unbearable for use. Furthermore, JP-A-4-182437 discloses a pressure-sensitive adhesive containing a copolymer of N-vinylacetamide. However, these are intended for the skin as an adherend, and when the subject other than the skin is intended, sufficient adhesive force has not been obtained.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to improve the above-mentioned drawbacks of the prior art by having excellent adhesive force even in a high humidity environment and on something other than the skin. And it is stable against acid and alkali, and
An object of the present invention is to provide a water-soluble pressure-sensitive adhesive resin that can be easily peeled off with water when the adhesive is removed, and the adhesive does not remain on the adherend and can be removed cleanly.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found that a copolymer containing an amino group-containing (meth) acrylate or (meth) acrylamide or vinyl ether and a vinylamide compound as essential components exhibits a water-soluble adhesive ability. As a result, they have completed the present invention. That is, the present invention provides (A) the following general formula [I],

[Chemical 2] (In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂
And R ₃ each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 1 to 5, and X represents
Indicates an ester, amide, or ether bond. ) Amino group-containing (meth) acrylate or (meth) acrylamide or vinyl ether and / or a quaternary salt thereof represented by

(B) A vinylamide compound represented by the following general formula [II] CH ₂ ═CHNHCOR ⁴ [II] (wherein R ⁴ represents a hydrogen atom or a methyl group) as an essential component as a monomer. The main component is a copolymer, the total amount of the monomer (A) and the monomer (B) is 50 to 100% by weight of the total amount of the monomer, and the glass transition point Tg is -50 ° C to 20 ° C.
C. relating to a water-soluble adhesive resin.

If the total amount of the monomer (A) and the monomer (B) in the above copolymer is less than 50% by weight, sufficient water-soluble tackiness cannot be obtained. Further, if the glass transition point Tg of the copolymer is less than -50 ° C, sufficient cohesiveness as a pressure-sensitive adhesive cannot be obtained. On the contrary, when Tg is 20 ° C. or higher, sufficient tackiness cannot be obtained. In the copolymer, the weight ratio of the monomer (A) and the monomer (B) is 25: 7.
5 to 75:25, more preferably 40:60 to 6
0:40 is good. When the monomer (A) is less than 25% and the monomer (B) exceeds 75%, sufficient tackiness cannot be obtained. On the contrary, when the amount of the monomer (A) exceeds 75% and the amount of the monomer (B) is less than 25%, sufficient water solubility or cohesiveness cannot be obtained, resulting in adhesive residue. The water-soluble pressure-sensitive adhesive resin of the present invention has a balance between the adhesiveness derived from the monomer (A) and the cohesiveness derived from the monomer (B), which are essential to the copolymer, and the water-solubility. The affinity with hydrophobic adherend, the hardly hydrolyzable property and the heat resistance due to B) can be extremely effectively realized by copolymerizing both monomers.

Specific examples of the monomer (A) used in the present invention include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate and N-methylaminoethyl ( (Meth) acrylate, N-ethylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N , N-dimethylaminopropyl (meth) acrylate, N, N-dipentylaminopentyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N- Dibutylaminoethyl (meth)
Acrylamide, N-methylaminoethyl (meth) acrylamide, N-ethylaminoethyl (meth) acrylamide, Nt-butylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dipentyl Aminopentyl (meth) acrylamide, N, N-dimethylaminomethyl vinyl ether, N, N-dimethylaminoethyl vinyl ether, N-methylaminoethyl vinyl ether, N-ethylaminoethyl vinyl ether, Nt-butylaminoethyl vinyl ether, N, Containing amino groups such as N-diethylaminoethyl vinyl ether, N, N-dibutylaminoethyl vinyl ether, N, N-dimethylaminopropyl vinyl ether, N, N-dipentylaminopentyl vinyl ether The (meth) acrylate or (meth) acrylamide or vinyl ether and /
Alternatively, quaternary salts thereof may be included, but the present invention is not limited thereto. Here, when the monomer (A) is in the form of a salt, an organic compound such as methyl chloride or dimethyl sulfate or an inorganic compound such as hydrochloric acid or sulfuric acid is used. on the other hand,
Specific examples of the monomer (B) include vinylamide compounds of N-vinylformamide and N-vinylacetamide.

In the present invention, the monomer (A),
The copolymerizable monomer other than (B) is 0% of the total amount of the monomer.
Up to 50% by weight can be copolymerized. Specifically, vinyl acetate, acrylamide, (meth) acrylic acid, sodium (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate. Hexyl (meth) acrylate, 2-methylbutyl (meth) acrylate,
3-Methylbutyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Octyl acrylate, lauryl (meth) acrylate,
Stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-cyanobutyl (meth) acrylate,
5-Cyano-3-oxapentyl (meth) acrylate,
2-Ethoxyethyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 2- (meth) acrylic acid
Methoxyethyl, 4-methoxypropyl (meth) acrylate, methyl vinyl ether, ethyl vinyl ether,
Examples thereof include vinyl monomers such as propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether and octyl vinyl ether.

Further, another polymer may be added to the extent that the adhesive property is not impaired and the water solubility is not impaired. Specific examples of the compound include (co) polymers of copolymerizable monomers other than the above-mentioned monomers (A) and (B), polyvinyl alcohol, vinyl acetate / vinylpyrrolidone copolymer, isobutylene / maleic anhydride. Examples thereof include acid copolymers and acrylonitrile / butadiene / acrylic acid copolymers. The adhesive resin of the present invention,
Although it has sufficient tackiness by itself, a suitable tackifier may be added if necessary so long as it does not impair the water solubility. Specific examples thereof include glycerin, polyethylene glycol, polyether polyol, polyoxyethylene alkylphenol, and rosin.

The method for producing the copolymer may be any of general solution polymerization, precipitation precipitation polymerization, inverse layer suspension polymerization, and the like.
It is not particularly limited. Further, the copolymer is not particularly limited in molecular weight, but generally, a copolymer having a molecular weight of several hundred thousand to several million is used. The resin for pressure-sensitive adhesive of the present invention is used in a solution state or processed into a pressure-sensitive adhesive molded body. The molded body is prepared as a single-layer pressure-sensitive adhesive sheet, or a plurality of pressure-sensitive adhesive sheets or tapes having a pressure-sensitive adhesive layer formed on a support. As the support, paper, wood, metal, glass fiber, cloth (nell, woven cloth, non-woven cloth, etc.), synthetic resin (polyurethane, ethylene-
Vinyl acetate copolymer, polyvinyl chloride, polyethylene terephthalate, polyester, etc.), cellulose derivative,
In addition, molded products such as a laminated film of these and a plastic film, a sheet (foil), a tape and the like can be mentioned. To facilitate storage of the obtained pressure-sensitive adhesive sheet, a release sheet treated with silicone or another suitable method is attached to the pressure-sensitive adhesive surface. Alternatively, it is desirable that the non-adhesive surface is treated with silicon or another appropriate method to form a release surface, and the adhesive surface is wound or overlapped so as to overlap with the adhesive surface. As the release sheet, polyethylene film, polypropylene film, release paper, cellophane, polyvinyl chloride, polyester, etc. are used. Further, the dried product of the adhesive resin may be directly prepared into tablets by using an appropriate tableting machine or the like.

The water-soluble adhesive resin of the present invention can be used, for example, as a kraft tape for corrugated cardboard, a gum tape, a courier or an address sticker / label for parcels. Separation is easy, and recovered paper can be simplified. It is also very useful for industrial products such as masking tapes for soldering, adhesive tapes / labels for household daily use, hygiene products such as hair removal tapes, sanitary napkins, etc. You can expect to provide something useful to.

[0013]

EXAMPLES Examples of the present invention will be shown below. In addition, a part shows a weight part. Example 1 (Formulation) N, N-dimethylaminoethyl acrylate 70 parts N-vinylacetamide 30 parts Water 300 parts An aqueous solution of these monomer mixtures was charged into a reactor,
After replacing with nitrogen, adjust the liquid temperature to 25 ° C under nitrogen atmosphere,
0.05 parts of 2'-azobis (2-amidinopropane) dihydrochloride was added, and an aqueous copolymer solution was obtained in a heat insulating system. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 2 (Formulation) N, N-dimethylaminoethylmethacrylate 30 parts N-vinylformamide 30 parts Butyl acrylate 40 parts Acetone 300 parts An acetone solution of these monomer mixtures was charged into a reactor, and after nitrogen substitution, The liquid temperature was adjusted to 56 ° C. under a nitrogen atmosphere, 0.05 part of α, α′-azobisisobutylnitrile was added, and the mixture was refluxed at the boiling point to obtain a copolymer. After cooling
The solvent is removed, the copolymer is dried and dissolved in water to 25%
An aqueous solution was used. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 2-1 (Prescription) Aqueous copolymer solution 40 obtained in Example 2
Sodium polyacrylate (Viscomate NP-7
0.8 (manufactured by Showa Denko)) was added. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 2-2 (formulation) 40 aqueous copolymer solution obtained in Example 2
10 parts of glycerin was added to the parts. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 3 (Formulation) N, N-dipentylaminopentyl vinyl ether 15 parts N-vinyl acetamide 40 parts Ethyl vinyl ether 45 parts Acetone 300 parts Polymerization was carried out in the same manner as in Example 2. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 4 (Formulation) N, N-diethylaminopropyl acrylate 40 parts N-vinylacetamide 15 parts 3-methoxypropyl acrylate 45 parts Acetone 300 parts Polymerization was carried out in the same manner as in Example 2. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 5 (Formulation) N, N-diethylaminoethyl acrylate 30 parts N-vinylformamide 25 parts Butyl vinyl ether 45 parts Acetone 300 parts Polymerization was carried out in the same manner as in Example 2. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Example 6 (Formulation) N, N-dipropylaminopentylacrylamide 25 parts N-vinylformamide 30 parts Heptyl acrylate 45 parts Ethyl acetate 300 parts Ethyl acetate solution of these monomer mixtures was charged into a reactor and nitrogen was added. After the replacement, the liquid temperature was adjusted to 56 ° C. under a nitrogen atmosphere, and α, α′-azobisisobutylnitrile 0.05
Parts were added and refluxed at the boiling point to obtain a copolymer. After cooling, the solvent was removed, the copolymer was dried and dissolved in water to
It was a 5% aqueous solution. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.
Shown in.

Example 7 (Formulation) N, N-dimethylaminoethyl acrylate 85 parts N-vinylformamide 15 parts Water 300 parts An aqueous solution of these monomer mixtures was charged into a reactor,
After replacing with nitrogen, adjust the liquid temperature to 25 ° C under nitrogen atmosphere,
0.05 parts of 2'-azobis (2-amidinopropane) dihydrochloride was added, and an aqueous copolymer solution was obtained in a heat insulating system. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Comparative Example 1 (Formulation) Acrylic acid 60 parts N-vinylacetamide 40 parts Water 300 parts Polymerization was carried out in the same manner as in Example 1. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

Comparative Example 2 (Formulation) N, N-diethylaminomethyl acrylate 60 parts Acrylamide 40 parts Water 300 parts Polymerization was carried out in the same manner as in Example 1. Using this copolymer aqueous solution, various evaluations were performed according to the following evaluation methods. The results are shown in Table 1.

[0024]

[Table 1]

(Evaluation Method) 40 parts of each polymer aqueous solution of Examples 1 to 7 and Comparative Examples 1 and 2 was dissolved in 10 parts of water under heating. Then, an appropriate amount of ethanol was added, and the mixture was uniformly mixed and applied on a vinylon film, and then dried at 60 ° C. Furthermore, it was left at 25 ° C. and 60% RH for 1 day to obtain an adhesive sheet. Using each pressure-sensitive adhesive sheet and a commercially available gum tape (Comparative Example 3), the tack force, pressure-sensitive adhesive force, water disaggregation and heat resistance of each pressure-sensitive adhesive resin were evaluated. However,
Each evaluation was performed at 25 ° C. and 65% RH except for heat resistance. In addition, the glass transition point of each polymer was measured, and the stability of the polymer was evaluated in aqueous acid and alkali solutions.

Each evaluation method is shown below. (1) Tack force Measured using a tack tester (manufactured by Rigaku Kogyo Co., Ltd.). A test piece cut out into a disk having a diameter of 15 mm was used.
Measurement conditions are contact time 5sec, probe moving speed 5mm
/ Sec, a load of 180 g, a probe made of stainless steel with a diameter of 10 mm wiped with methanol was used, and an average value of 5 measurements was taken. (2) Adhesive force (180 ° peeling force) A 3 cm × 7 cm test piece was reciprocated once with a 2 kg pressure roller at a moving speed of 2 cm / sec and pressure-bonded onto a stainless steel plate wiped well with ethanol. The stress at 180 ° peeling from a stainless steel plate at 30 cm / min was measured three times with a digital force gauge, and the average was taken.

(3) Disaggregation by water A test piece of 3 cm × 3 cm was placed in a beaker containing 1 liter of water, stirred for 3 minutes, taken out of the sheet, and the state of the adhesive layer was judged by touch. Judgment Criteria: No adhesive remains. X: The adhesive remains. (4) Heat resistance Using a test piece (2 cm x 4 cm), one end was attached and fixed to a stainless steel plate (half of the test piece, 2 cm x 2 c).
m was adhered), placed in a constant temperature bath at 70 ° C., a 500 g load was applied to the other end using a heat-resistant creep tester (manufactured by Toyo Seiki), and the time to drop by shearing was measured. .

(5) Glass transition point Tg Each of the polymer aqueous solutions obtained in Examples 1 to 7 and Comparative Examples 1 and 2 was dried at 105 ° C. for 4 hours to evaporate the water content. The glass transition point was measured using a differential scanning calorimeter (Seiko Denshi Kogyo). (6) Stability in aqueous acid and alkali solution The pH of each polymer aqueous solution obtained in Examples 1 to 7 and Comparative Examples 1 and 2 was adjusted to 3 or 10, kept at 40 ° C, and the aqueous solution after 7 days. Was observed.

From the results shown in Table 1, Examples 1 to 7 have good disaggregation properties with water, can exhibit excellent tack force and adhesive force, and are stable under acid and alkaline conditions. I understand.

Example 8 40 parts of the polymer aqueous solution obtained in Example 2 was dissolved by heating in 10 parts of water. Next, an appropriate amount of ethanol was added, and the mixture was uniformly mixed, applied to kraft paper, and then dried at 60 ° C. Further, it was left for 1 day at 25 ° C. and 60% RH to obtain a kraft adhesive tape. This adhesive tape was attached to a cardboard. When this was put in water, the kraft paper and cardboard were peeled off cleanly, and the pulp could be easily disintegrated and collected.

[0031]

The water-soluble adhesive resin of the present invention has a good balance between adhesiveness and water solubility. That is, it has excellent adhesive strength even in a high humidity environment, and
When removing the sticky matter, it can be easily peeled off with water, and the sticky agent does not remain on the adherend and can be removed cleanly. Therefore, the industrial utility value is extremely large. For example, when used as a kraft tape for corrugated cardboard, a gum tape, an address sticker / label for parcel delivery or parcel, it is easy to separate the corrugated cardboard from the tape / labels and the collection of used paper can be simplified. It is also very useful for industrial products such as masking tapes for soldering, adhesive tapes / labels for household daily use, hygiene products such as hair removal tapes, sanitary napkins, etc. You can expect to provide something useful to.

Claims (2)

[Claims] 1. (A) The following general formula [I]: (In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂
And R ₃ each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 1 to 5, and X represents
Indicates an ester, amide, or ether bond. ), An amino group-containing (meth) acrylate or (meth) acrylamide or vinyl ether, and / or a quaternary salt thereof, and (B) the following general formula [II] CH ₂ ═CHNHCOR ⁴ [II] ( In the formula, R ⁴ represents a hydrogen atom or a methyl group.) The main component is a copolymer having a vinylamide compound represented by the formula (1) as an essential component, and the sum of the monomer (A) and the monomer (B). Is 50 to 100% by weight of the total amount of the monomers, and the glass transition point Tg is -50 ° C to 20 ° C.
Water-soluble pressure-sensitive adhesive resin that is ℃. 2. The water-soluble pressure-sensitive adhesive resin according to claim 1, wherein the weight ratio of the monomer (A) to the monomer (B) in the copolymer is 25:75 to 75:25.