JPH06322355A - Water-soluble or water-dispersible pressure-sensitive adhesive composition and tacky tape using the same - Google Patents

Abstract

PURPOSE:To adhesive strength under conditions of low temperatures and humidities and useful as a tacky tape, etc., by blending a base polymer such as a water-soluble polymer with a water-soluble plasticizer and a surfactant in a specific proportion. CONSTITUTION:The adhesive composition is obtained by blending (A) 100 pts.wt. base polymer such as a water-soluble or a water-dispersible copolymer of an acrylic acid (derivative) and a salt containing sulfonic acid with (B) 10-100 pts.wt. water-soluble plasticizer such as a polyether polyol and (C) 1.0X10<-4> to 10 pts.wt. surfactant such as a polyoxyethylene alkyl ether. Furthermore, the tacky tape having the water solubility or water dispersibility is prepared by forming this composition on the surface of a water-soluble or a water- dispersible substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is not limited in its application, but is, for example, a water-soluble or water-dispersible pressure-sensitive adhesive composition used for adhesive tapes and sheets for splicing in the paper industry. Specifically, the present invention relates to a water-soluble or water-dispersible pressure-sensitive adhesive composition having excellent initial adhesiveness not only at room temperature but also at low temperature and low humidity, and an adhesive tape or sheet using the same.

[0002]

2. Description of the Related Art Water-soluble adhesives are already known, for example, so-called gum tapes in which glue, dextrin, polyvinyl alcohol, etc. are applied to a substrate are well known. These types of tapes do not exhibit pressure-sensitive adhesiveness in the dry state because they lack rubber elasticity and viscosity, and the adhesive force is activated only by applying water. For this reason, a complicated wetting device is required for industrial use, and even if it is used for general purposes, it has a drawback that it is troublesome to handle as seen in bonding stamps and envelopes.

On the other hand, a water-soluble or water-dispersible adhesive which does not have such drawbacks and always exhibits pressure-sensitive adhesiveness has been proposed. For example, US Pat. No. 2,838,421
Specification, Japanese Patent Publication No. 50-84578, Japanese Patent Publication No. 52
No. 22768, Japanese Patent Publication No. 49-23813, etc., a polymer containing a carboxyl group in the molecule such as polyacrylic acid as a base polymer or a water-soluble polymer such as an alkali metal salt, an amine salt or an alkanolamine salt thereof. A pressure-sensitive adhesive is disclosed in which a salt is used and a water-soluble or water-dispersible plasticizer such as a polyether polyol, a polyhydric alcohol and an alkanolamine salt of an acidic rosin is added to the base polymer.

All of these pressure-sensitive adhesives are based on a monomer containing a carboxyl group, which is a highly polar functional group, as a raw material component in order to impart a function such as water solubility or water dispersibility. While using polymers,
Since this type of polymer has a high glass transition temperature and does not show sufficient pressure-sensitive adhesiveness at room temperature by itself, this base polymer further has the above-mentioned water-soluble or water-dispersible properties such as polyether polyol and polyhydric alcohol. By adding a large amount of a plasticizer, a desired pressure-sensitive adhesive property is imparted.

On the other hand, JP-A-2-120381 discloses that a carboxyl group-containing polymer having a low glass transition temperature is produced using a caprolactone adduct of acrylic acid,
By using this as a base polymer, sufficient pressure-sensitive adhesiveness can be obtained without adding a large amount of a water-soluble or water-dispersible plasticizer such as polyether polyol or polyhydric alcohol. Alternatively, a water dispersible pressure sensitive adhesive is disclosed.

[0006]

As described above, since the conventional water-soluble polymer has a high elastic modulus at room temperature, it is necessary to add a large amount of a plasticizer. Therefore, there is a problem that the plasticizer migrates to the base material side such as paper and bleeds the paper especially when stored for a long time or under high temperature and high humidity. In order to solve this, the applicant has proposed a polymer having a low elastic modulus at room temperature,
We succeeded in reducing the amount of plasticizer. (Japanese Patent Application No. 3-263066
However, depending on the temperature conditions, the initial adhesive strength may decrease even at room temperature, and may further decrease under low temperature and low humidity. It is considered that this is because the water content in the pressure-sensitive adhesive works as a plasticizer, and even if the amount of the plasticizer is reduced, the initial adhesive strength is still unsatisfactory, especially under low temperature and low humidity, and there is room for further improvement. was there.

[0007]

The present invention has been made to solve the problems of the prior art, and could be solved by incorporating a surfactant into a pressure-sensitive adhesive composition. It is presumed that the reason is that the surfactant promotes the compatibility between the water-soluble polymer and the plasticizer and can enhance the effect of the plasticizer in the pressure-sensitive adhesive composition.

That is, in the present invention, 1 part of the water-soluble plasticizer is added to 100 parts by weight of the water-soluble or water-dispersible base polymer.
0 to 100 parts by weight, and a surfactant of 1.0 × 10 ⁻⁴
The present invention relates to a water-soluble or water-dispersible pressure-sensitive adhesive composition containing 10 parts by weight, and an adhesive tape using the same.

The water-soluble or water-dispersible base polymer in the present invention is not particularly limited, but a copolymer containing a sulfone group or a salt thereof is preferable, and particularly acrylic acid or a derivative thereof and a sulfonic acid-containing salt are used. Copolymers are preferred.

Concretely, for example, itaconic acid, maleic acid, 2-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, alkyl acrylate having an alkyl group having 1 to 12 carbon atoms. Esters, vinyl acetate, acrylonitrile and the like can be mentioned, and alkoxyethyl acrylate, styrene sulfonate, and caprolactone adduct of acrylic acid are particularly preferably used.

The surfactant used in the present invention is an anionic type such as a fatty acid salt represented by the following (Chemical formula 1),
Examples thereof include cationic surfactants such as tetraalkylammonium salts represented by (Chemical Formula 2) and nonionic surfactants such as polyoxyethylene alkyl ether represented by (Chemical Formula 3).

[0012]

[Chemical 1]

[0013]

[Chemical 2]

[0014]

[Chemical 3]

A nonionic surfactant is preferably used in the water-soluble or water-dispersible pressure-sensitive adhesive composition of the present invention because it has good compatibility with a polymer. Examples of such nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene sorbitan acid ester.

The amount of such a surfactant blended is 1.0 × 10 ^{−4 with} respect to 100 parts by weight of the water-soluble base polymer.
10 to 10 parts by weight, preferably 1.0 × 10 ^{−4 to} 5 parts by weight. If the amount of the surfactant exceeds 10 parts by weight, the surface of the pressure-sensitive adhesive is modified and repellency occurs, resulting in poor coatability. On the other hand, if the amount of the surfactant is less than 1.0 × 10 ⁻⁴ parts by weight. In that case, the effect of the addition cannot be obtained, and the desired initial adhesive force cannot be achieved.

As the water-soluble plasticizer, those usually used can be used. For example, water-soluble or water-dispersible plasticizers such as polyether polyol, polyhydric alcohol, and alkanolamine salt of acidic rosin. Is mentioned.

The amount of the plasticizer compounded is 10 to 100 parts by weight, preferably 10 × 50 parts by weight, based on 100 parts by weight of the water-soluble base polymer. If the amount is less than 10 parts by weight, the pressure-sensitive adhesiveness is not sufficient, while 10
If it exceeds 0 parts by weight, the low-speed shear peeling force may be reduced or bleeding may occur.

In addition to the above-mentioned essential components, the pressure-sensitive adhesive composition of the present invention may contain various known additives such as tackifiers, antioxidants and pigments, if necessary. You can also

In the present invention, the pressure-sensitive adhesive composition of the present invention can be formed on one side or both sides of a substrate to give the water-soluble or water-dispersible pressure-sensitive adhesive tape of the present invention. The base material is not particularly limited as long as it has water solubility or water dispersibility, and examples thereof include crepe paper, Japanese paper, kraft paper, or a composite product thereof.

[0021]

INDUSTRIAL APPLICABILITY In the present invention, by incorporating a surfactant in the pressure-sensitive adhesive composition, even when a small amount of a water-soluble plasticizer is contained, it is not only at room temperature, but especially at low temperature and low humidity. Excellent initial adhesive strength can be obtained.

[0022]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. In addition, "part" below means a weight part. Example 1 Water-soluble base polymer (methoxyethyl acrylate,
Water-soluble plasticizer (hexaol, Sanyo Chemical Co., Ltd., Sannix SP75) per 100 parts of caprolactone acrylate and sodium styrenesulfonate copolymer)
0) 30 parts, surfactant (polyoxyethylene sorbitan fatty acid ester, Sanyo Chemical Co., Ltd., Ionette T-20)
1 part of C (lauric acid, n = 20)) was mixed to obtain a pressure-sensitive adhesive composition of the present invention. The obtained pressure-sensitive adhesive composition was applied to a non-woven fabric by double-sided coating so as to have a total thickness of 60 μm, and dried by heating at 110 ° C. for 3 minutes to prepare an adhesive tape of the present invention. Was used as a sample for the adhesive strength test.

Example 2 To 100 parts of a water-soluble base polymer (same as Example 1), 50 parts of a water-soluble plasticizer (same as Example 1) and 5 parts of a surfactant (same as Example 1) were blended. Then, the pressure-sensitive adhesive composition of the present invention was obtained. Furthermore, the adhesive tape of the present invention was prepared in the same manner as in Example 1.

Example 3 To 100 parts of a water-soluble base polymer (same as Example 1), 10 parts of a water-soluble plasticizer (same as Example 1) and 0.1 part of a surfactant (same as Example 1). Was blended to obtain the pressure-sensitive adhesive composition of the present invention. Furthermore, the adhesive tape of the present invention was prepared in the same manner as in Example 1.

Comparative Example 1 A pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape were prepared in the same manner as in Example 1 except that the water-soluble plasticizer of Example 1 was 30 parts and the surfactant was 0 part. .

Comparative Example 2 A pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape were prepared in the same manner as in Example 1 except that the water-soluble plasticizer of Example 1 was 50 parts and the surfactant was 20 parts.

Example 4 30 parts of a water-soluble plasticizer (same as in Example 1), 100 parts of a water-soluble base polymer (same as in Example 1), and a surfactant (polyoxyethylene sorbitan fatty acid ester, Sanyo Kasei Co., Ltd.) Ionet T-80C (n = oleic acid =
20)) 1 part was blended to obtain the pressure-sensitive adhesive composition of the present invention. Furthermore, the adhesive tape of the present invention was prepared in the same manner as in Example 1.

Example 5 To 100 parts of a water-soluble base polymer (same as Example 1), 50 parts of a water-soluble plasticizer (same as Example 1) and 5 parts of a surfactant (same as Example 4) were blended. Then, the pressure-sensitive adhesive composition of the present invention was obtained. Furthermore, the adhesive tape of the present invention was prepared in the same manner as in Example 1.

Example 6 To 100 parts of a water-soluble base polymer (same as Example 1), 10 parts of a water-soluble plasticizer (same as Example 1) and 0.1 part of a surfactant (same as Example 4). Was blended to obtain the pressure-sensitive adhesive composition of the present invention. Furthermore, the adhesive tape of the present invention was prepared in the same manner as in Example 1.

The adhesive tapes obtained in each of the above Examples and Comparative Examples were evaluated for initial adhesive strength under low temperature and low humidity, shear adhesive strength, and coatability of the pressure-sensitive adhesive composition by the following methods. The results are shown in [Table 1].

[Initial adhesion test (under low temperature and low humidity)] The sample was cut into a width of 20 mm, and the sample and the adherend copy paper were aged for 2 hours in 5 ° C. × 40% RH, and each was subjected to the atmosphere. It was confirmed whether or not it could be instantly stuck to a copy paper having a load (5 g, 10 g, 15 g) and lifted. Evaluation result × ─── Do not lift, △ ───
Lift 5 to 10g ○ ─── Lift 10 to 15g, ◎ ─── Lift 15g or more

[Shear Adhesion] A sample of 20 mm × 20 mm
Cut into 2 pieces, press-bonded to the adherend cardboard with one round trip of a 2 kg roller, and after aging for 30 minutes in 23 ° C x 65% RH,
The tensile speed was measured at 300 mm / min.

[Coatability] The obtained pressure-sensitive adhesive composition was
It was hand-painted using an applicator, and the presence or absence of glue streaks and the repellency of the glue were confirmed. Evaluation results ○ ─── No glue stripes, no glue repelling × ───

[0034]

[Table 1]

Claims (5)

[Claims] 1. 100 to 100 parts by weight of a water-soluble or water-dispersible base polymer, 10 to 100 parts by weight of a water-soluble plasticizer, and 1.0 × 10 ⁻⁴ to 10 parts by weight of a surfactant are blended. A water-soluble or water-dispersible pressure-sensitive adhesive composition comprising: 2. The water-soluble or water-dispersible pressure-sensitive adhesive composition according to claim 1, wherein the water-soluble or water-dispersible base polymer contains a sulfone group or a salt thereof. 3. The water-soluble or water-dispersible pressure-sensitive adhesive composition according to claim 1, wherein the surfactant is a nonionic surfactant. 4. The water-soluble or water-dispersible pressure-sensitive adhesive composition according to claim 3, wherein the surfactant is polyoxyethylene alkyl ether. 5. A water-soluble or water-dispersible pressure-sensitive adhesive tape comprising the pressure-sensitive adhesive composition according to claim 1 provided on at least one surface of a water-soluble or water-dispersible substrate.