JPH08337765A - Aqueous contact adhesive - Google Patents

Abstract

PURPOSE: To obtain the subject adhesive by directly adding a tackifier resin to a chloroprene rubber latex stable in a specific pH range in the presence of an alkali substance, dissolving and blending, having safety, a high drying rate, excellent in initial bond strength and contacting properties. CONSTITUTION: (B) A tackifier resin (e.g. rosin, a polymerized rosin, a dibasic acid-modified rosin, a maleic acid resin, an acrylic resin, etc.) having >=100 acid value which is not predissolved in a solvent is directly added to (A) a chloroprene rubber latex stable at least in a range of pH 6.5 to pH 8.0 alone or a mixed solution of the latex and another polymer emulsion in the presence of an alkali substance. The tackifier resin is dissolved in the solution and blended. The amount of the component B is preferably 10-250 pts.wt. based on 100 pts.wt. of the rubber component in the component A. The latex of the component A, for example, is obtained by copolymerizing chloroprene with an ethylene-based unsaturated carboxylic acid copolymerizable with chloroprene in the presence of a polyvinyl alcohol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to building materials for houses, adhesion of foam in bedding, etc., industrial fields such as vehicle interiors, woodworking furniture, etc., fields used at construction sites such as building interiors,
Also, it can be used in the field of application of solvent-based adhesives that are widely used in the field of general household use.Because it is an aqueous type, it does not harm the environment and there is no danger. And a contact property, and a high ratio of the total of resin content and rubber content (hereinafter simply referred to as resin content).

[0002]

2. Description of the Related Art A conventional water-based contact adhesive is prepared by dissolving a tackifying resin having a low acid value in an organic solvent such as an aromatic hydrocarbon or by pulverizing the resin and then adding an emulsifier and water for adhesion. An emulsion of the imparting resin was prepared and blended with the chloroprene rubber latex.

The adhesive obtained by such a method contains an organic solvent that exerts an environmental load, and a new emulsifier is added to emulsify the resin. As a result, the emulsifier in the adhesive is The amount of this emulsifier adversely affects the adhesive performance, the adhesiveness is inferior, the adhering speed is slower than the solvent-type adhesive, the tackiness in a semi-dried state is not present, and the contact property is inferior.

In JP-A-6-322347, a tackifying resin having a high acid value is dissolved in an alcoholic solvent and added to a polymer emulsion such as chloroprene rubber latex without newly adding an emulsifier. An adhesive composition is shown. Although these improve the problem of environmental load and obtain good contact properties, the resin content cannot be increased because the resin is previously dissolved in an alcohol solvent, which is a drawback of the water-based adhesive. , Can not dry faster and increase the initial bond strength.

[0005] These conventional water-based contact adhesives have not been widely used because of the above-mentioned drawbacks. In addition, in applications where initial adhesive strength is required, solvent-based adhesives containing a large amount of solvent are used in a wide range of fields because of their excellent adhesiveness, fast drying speed, and ease of operation.

[0006]

As described above, the conventional water-based adhesive has various problems, but in the conventional solvent-based adhesive, most of the solvents contained therein are toxic. There is a high risk of polluting the environment. There is a risk of poisoning if the solvent-based adhesive is used in a closed room, especially for interior work during remodeling or when used in a general home. Furthermore, from the time of manufacture to the time of use, there is a drawback that there is always a high risk of fire when dealing with solvent-based adhesives, including intermediate transportation, storage, and display in retail stores.

The present invention solves the above-mentioned problems of the prior art, is an aqueous system, does not harm the environment, and there is no risk of fire.
It is an object of the present invention to provide an aqueous contact adhesive having a high resin content, which has a fast drying rate and is excellent in initial adhesive strength and contact property.

[0008]

In view of the above, the present inventors have earnestly studied an aqueous adhesive that does not use an organic solvent and does not newly use an emulsifier and has a high drying rate. A high tackifying resin, stable in the presence of alkaline substances, at least in the region of pH 6.5-8.0,
Add chloroprene rubber latex alone or to a mixed liquid of chloroprene rubber latex and other polymer emulsion directly without being dissolved in a solvent in advance, and by dissolving in these liquids, without newly adding an emulsifier. It was found that an aqueous adhesive having a high resin content was obtained, and that this aqueous adhesive was excellent in initial adhesive strength and contact properties and had a high drying rate, and arrived at the present invention.

That is, the aqueous contact adhesive of the present invention has a pH of at least 6.5 in the presence of an alkaline substance.
To a chloroprene rubber latex which is stable in the range of ˜8.0, a tackifying resin having an acid value of 100 or more is directly added to a chloroprene rubber latex alone or a mixed solution of the chloroprene rubber latex and another polymer emulsion without being previously dissolved in a solvent. Then, they are dissolved and blended in these liquids.

In the present invention, the tackifying resin having an acid value of 100 or more is rosin, polymerized rosin, hydrogenated rosin, dibasic acid-modified rosin typified by maleic acid-modified rosin, styrene-maleic acid copolymer resin, The maleic acid resin and the acrylic resin are mentioned, but not limited thereto. The acid value referred to herein is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the resin.

If the acid value is less than 100, water-solubilization with an alkaline substance is generally insufficient, and tackification is carried out in the chloroprene rubber latex alone or in a mixed liquid of the chloroprene rubber latex and another polymer emulsion. A resin cannot be melt-blended to obtain a stable adhesive. Even if it is well dissolved, the viscosity becomes too high, and the heat resistance or contact property is insufficient, so that satisfactory performance as an adhesive cannot be obtained.

The tackifying resin used in the present invention is used not only for increasing the resin content, but also for the purpose of imparting contact property and improving adhesiveness, and the resin is appropriately selected according to the purpose.
Used alone or in combination of two or more.

The amount of the tackifying resin compounded is preferably 10 parts by weight to 250 parts by weight, and particularly preferably 20 parts by weight to 80 parts by weight, per 100 parts by weight of the rubber content of the chloroprene rubber latex. If the amount is less than 10 parts by weight, the resin content does not become so high, and the effect of improving the contact property and the adhesive property does not significantly appear. If it exceeds 250 parts by weight, the film becomes hard and brittle, and the adhesive property is deteriorated.

The alkaline substance used in the present invention is used for solubilizing the tackifying resin having an acid value of 100 or more, and the alkaline substance is ammonia water, triethanolamine, diethanolamine, sodium hydroxide, potassium hydroxide. Etc. can be used, but are not particularly limited thereto. The amount of alkaline substance added is
Although it depends on the acid value of the tackifier resin, it substantially keeps the stable pH region of the chloroprene rubber latex alone or the mixture of the chloroprene rubber latex and the other polymer emulsion in order to make the tackifier resin water-soluble. The minimum required amount can sufficiently fulfill the purpose.

The chloroprene rubber latex used in the present invention is stable in the process of dissolving the tackifying resin in the presence of an alkaline substance, that is, at least pH.
Can be used as long as it is stable in the range of 6.5 to 8.0. The wider the pH stable region is, the easier it is to manufacture without needing to control the pH in the process of dissolving the tackifying resin, and the storage stability of the obtained adhesive is also good. Therefore, in the present invention, including chloroprene rubber latex stable in the range of 6.5 to 8.0 as the pH range, the lower limit of 6.5 and the upper limit of 8.0 in the pH range are stable.
Chloroprene rubber latex having a wider pH stable range can also be used. For example, the pH range should have a lower limit of 6.5 and an upper limit of 9.0, a lower limit of 4.5 and an upper limit of 8.0, and a lower limit of 3.5 and an upper limit of 9.5. You can However, the lower limit is 7.
0 and the upper limit is 9.5, and the lower limit is 3.5 and the upper limit is 7.
5 cannot be used. The chloroprene rubber latex having a wide pH stable range includes a chloroprene rubber latex obtained by copolymerizing chloroprene and an ethylenically unsaturated carboxylic acid copolymerizable with chloroprene in the presence of polyvinyl alcohol, and polyvinyl alcohol and glycol. There is a chloroprene rubber latex obtained by copolymerizing chloroprene and an ethylenically unsaturated carboxylic acid copolymerizable with chloroprene in the presence of ethers.

In the present invention, the chloroprene rubber latex and other polymer emulsion can be mixed and used. The polymer emulsion used by mixing with the chloroprene rubber latex is stable without gelation at the time of mixing, and the mixed solution is stable in the process of dissolving the tackifying resin in the presence of the alkaline substance, that is, as described above. As in the case of the chloroprene rubber latex, any one can be used as long as it is stable at least in the pH range of 6.5 to 8.0. The wider the pH stable region of this mixed solution, the easier it is to manufacture without the need to control the pH in the process of dissolving the tackifying resin, and the better the storage stability of the obtained adhesive. As the polymer emulsion, an acrylic resin emulsion, a styrene-butadiene rubber latex, a urethane resin emulsion, a vinylidene chloride resin emulsion, an ethylene-vinyl acetate copolymer resin emulsion, and a tackifying resin having an acid value of 100 or less, such as a petroleum resin, an alkylphenol. Resin, rosin or modified rosin, terpene resin, terpene phenolic resin and asphalt emulsion, etc., but are not limited to these, as long as the above conditions are satisfied, any one of the polymer emulsions or Two or more types can be used.

The water-based contact adhesive of the present invention may optionally contain a water-soluble polymer, a resin having an acid value of 100 or less and soluble in alkaline water, a filler, a wetting agent, a preservative, a rust preventive, an acid absorbent. , An antioxidant, and a coupling agent such as silane and titanium may be added.

The adhesive thus prepared is packed in a tube, and the adhesive is extruded from a nozzle of the tube to be applied in a bead shape on one side of the adherend, or by using a brush, a roll coater or a spray gun. Apply it on one or both sides and bond it immediately, or after a suitable open time, bond and bond.

[0019]

In the adhesive of the present invention, the tackifying resin is not dissolved in a solvent in advance and blended with the chloroprene rubber latex, but in the chloroprene rubber latex alone or in a mixed liquid of the chloroprene rubber latex and another polymer emulsion. Among them, the tackifying resin is directly melted and blended to increase the resin concentration, whereby the drying speed is increased and the initial adhesive strength is increased. In addition, the water-solubilized tackifying resin can always exert a tackifying effect in the process of drying the adhesive, and since it does not use an emulsifier newly, it has excellent adhesiveness to various materials and is a solvent in a semi-dried state. It exhibits a thread-like state like a mold adhesive and exhibits good adhesive strength.

Further, in general, when the resin content is increased, the distance between the particles is shortened, so that the latex becomes unstable unless the amount of the emulsifier is increased. However, in the adhesive according to the present invention, which has been solubilized with an alkali to increase the resin content, it is presumed that the distance between particles is not shortened despite the high resin content. Therefore, the adhesive of the present invention has very good stability despite the high resin content.

[0021]

【Example】

Example 1 100 parts by weight of a carboxyl group-containing chloroprene rubber latex [trade name LC-550 manufactured by Denki Kagaku Kogyo Co., Ltd., nonvolatile content (rubber content), pH 7.0] and an acid value of 300.
5 parts by weight of maleic acid modified rosin (manufactured by Arakawa Chemical Industry Co., Ltd., Marquide No. 33) was added, 1 part by weight of ammonia water was gradually added with stirring, and the mixture was stirred at 80 ° C. for 3 hours, dissolved and cooled. Thus, an aqueous contact adhesive having a nonvolatile content (total of resin content and rubber content) of 50.0% was obtained.

Example 2 In the same manner as in Example 1, 100 parts by weight of a carboxyl group-containing chloroprene rubber latex was added to 10 parts by weight of a maleic acid-modified rosin having an acid value of 270 (trade name: Marquid No. 34, manufactured by Arakawa Chemical Industry Co., Ltd.). Part and hydrogenated rosin with an acid value of 165 (trade name: FORAL A, manufactured by Rika Hercules Co.
X) 10 parts by weight was charged, 4 parts by weight of ammonia water was added, and the mixture was stirred and dissolved at 80 ° C. for 3 hours and then cooled to obtain an aqueous contact adhesive having a nonvolatile content (resin content and rubber content) of 54.8%. Obtained.

Example 3 In the same manner as in Example 1, 100 parts by weight of a carboxyl group-containing chloroprene rubber latex was added to 10 parts by weight of a maleic acid-modified rosin having an acid value of 270 (trade name: Marquid No. 34, manufactured by Arakawa Chemical Industry Co., Ltd.). Part and hydrogenated rosin with an acid value of 165 (trade name: FORAL A, manufactured by Rika Hercules Co.
X) 20 parts by weight were added, 5 parts by weight of ammonia water was added, and the mixture was stirred and dissolved at 80 ° C. for 3 hours and then cooled to be 57.8% of nonvolatile content (total of resin content and rubber content), water-based contact adhesive. Got

Example 4 In the same manner as in Example 1, 120 parts by weight of maleic acid-modified rosin was added to 100 parts by weight of carboxyl group-containing chloroprene rubber latex, 20 parts by weight of aqueous ammonia was added, and the mixture was heated at 80 ° C. for 3 hours. After stirring and dissolving, the mixture was cooled to obtain an aqueous contact adhesive having a nonvolatile content (resin content and rubber content) of 70.6%.

Example 5 In the same manner as in Example 1, 100 parts by weight of a carboxyl group-containing chloroprene rubber latex was charged with 10 parts by weight of hydrogenated rosin having an acid value of 165 (trade name: FORAL AX, manufactured by Rika Hercules Co., Ltd.), 2 parts by weight of aqueous ammonia was added, and the mixture was stirred and dissolved at 80 ° C. for 3 hours and then cooled to obtain an aqueous contact adhesive having a nonvolatile content (resin content and rubber content) of 51.7%.

Example 6 In the same manner as in Example 1, 90 parts by weight of a carboxyl group-containing chloroprene rubber latex and an acrylic resin emulsion [trade name AE32 manufactured by Nippon Latex Kako Co., Ltd.]
2 Nonvolatile content (resin content) 52% pH 8.0] in a mixed solution with 10 parts by weight, maleic acid-modified rosin having an acid value of 270 (trade name Marquid No. 3 manufactured by Arakawa Chemical Industry Co., Ltd.)
4) 10 parts by weight and 10 parts by weight of hydrogenated rosin (trade name: FORAL AX, manufactured by Rika Hercules Co., Ltd.) having an acid value of 165 were charged, 4 parts by weight of aqueous ammonia was added, and the mixture was mixed at 80 ° C. for 3 days.
After stirring and dissolving for an hour, the mixture was cooled to obtain an aqueous contact adhesive having a nonvolatile content (resin content and rubber content) of 55.2%.

Example 7 In the same manner as in Example 1, 100 parts by weight of a carboxyl group-containing chloroprene rubber latex was added to a styrene-maleic acid copolymer resin having an acid value of 190 (trade name: Alastar 700 manufactured by Arakawa Chemical Industry Co., Ltd.). 10 parts by weight of hydrogenated rosin (trade name: Foral AX, manufactured by Rika Hercules Co., Ltd.) having an acid value of 165 and 4 parts by weight of ammonia water are added, and the mixture is stirred and dissolved at 80 ° C. for 3 hours and then cooled to obtain a nonvolatile content. A total of 54.8% (total of resin and rubber) water-based contact adhesive was obtained.

Comparative Example 1 100 parts by weight of a carboxyl group-containing chloroprene rubber latex [LC-550 non-volatile (rubber) 48% by Denki Kagaku Kogyo Co., Ltd.] terpene phenol resin emulsion [Arakawa Chemical Co., Ltd. trade 50% by weight of Tamanor E100 nonvolatile content (resin content) 53% was added and mixed with stirring to obtain an adhesive having a nonvolatile content (resin content and rubber content) of 49.7%.

COMPARATIVE EXAMPLE 2 Chloroprene rubber-based solvent adhesive manufactured by Konishi Co., Ltd. [trade name: Bond G10, non-volatile content (total of resin content and rubber content)]
23%] was used as a comparative product.

COMPARATIVE EXAMPLE 3 To 4 parts by weight of aqueous ammonia and 20 parts by weight of ethyl alcohol, 10 parts by weight of maleic acid-modified rosin having an acid value of 270 (trade name Marquid No. 34 manufactured by Arakawa Chemical Industry Co., Ltd.) and an acid value of 165 were added. 10 parts by weight of hydrogenated rosin (Rika Hercules Co., Ltd. product name FORAL AX) is added,
The mixture was stirred and dissolved at 80 ° C. for 3 hours and then cooled to obtain a resin solution.
This resin solution was used as a carboxyl group-containing chloroprene rubber latex [trade name LC-5 manufactured by Denki Kagaku Kogyo Co., Ltd.
50 non-volatile content (rubber content) 48% pH 7.0] was added to 100 parts by weight and sufficiently mixed with stirring to obtain an adhesive having a non-volatile content (total of resin content and rubber content) of 47.2%.

The adhesive properties of the adhesives of Examples 1 to 7 and Comparative Examples 1 to 3 were evaluated, and the results are shown in Table 1 below. Each test shown in Table 1 below is performed at room temperature of 20 ° C. and humidity of 50%.
Was carried out under the conditions of

[0032]

[Table 1]

(Note) Threading property: An adhesive agent was applied to plywood at 75 g / m ² and the presence of threading was determined by pressing a finger in a semi-dried state. The ⊚ mark is extremely good, the ∘ mark is good, and the Δ mark is a slight stringing.

Drying time: 0.15 m of adhesive on the glass plate
It was applied in a thickness of m and the time until it became transparent was measured. *
The mark indicates that the adhesive could not be measured by this method because it was solvent-based.

Bonding strength within 1 minute of bonding: Adhesives of 75 g / m ^{2 were} applied to both birch materials, and after each open time, they were bonded together, pressed by hand and pressed within 10 minutes within 10 minutes.
The burst adhesive strength was measured at a speed of mm / min (unit: N /
25 mm).

Adhesive strength 7 days after lamination: Adhesive was applied to both birch materials at 75 g / m ² and the open time was 1
After 5 minutes (5 minutes in Example 3), the pieces were laminated, pressed by hand and pressure-bonded, and after 7 days, the compression shear adhesive strength was measured at a speed of 10 mm / minute (unit: N / cm ² ).

Further, the adhesives of Examples 1 to 7 and Comparative Examples 1 to 3 were evaluated under the conditions of room temperature of 20 ° C. and humidity of 50% in order to evaluate the adhesive properties when the adherend was changed. Two
75 g / m ² of an adhesive is applied to both adherends shown in Fig. 3, the open time is set to 15 minutes (5 minutes in Example 4), the pieces are attached, pressed by hand and pressure-bonded for 7 days. / Rubber was measured for peeling adhesive strength at a speed of 200 mm / min, and hard PVC / hard PVC was measured for tensile shear adhesive strength at a speed of 10 mm / min. The results are shown in Table 2 below.

[0038]

[Table 2]

As is clear from the results shown in Tables 1 and 2, the aqueous contact adhesive of the present invention has an initial adhesive strength higher than that of the adhesive of Comparative Example 1 which is a normal chloroprene adhesive. Excellent in stringiness and stringiness, and
Excellent adhesion strength for adherends other than birch. Further, comparing the water-based contact adhesive of the present invention with the conventional solvent-based adhesive of Comparative Example 2, the adhesive of the present invention does not contain harmful or dangerous organic solvent, and the solvent-based adhesive of Comparative Example 2 is also included. It has adhesive properties almost equal to. Furthermore, the water-based contact adhesive of the present invention is superior in initial adhesive strength to the conventional water-based contact adhesive of Comparative Example 3.

[0040]

EFFECTS OF THE INVENTION The water-based contact adhesive of the present invention has a high resin content and therefore has a faster drying rate than conventional water-based contact adhesives and is excellent in initial adhesive strength, and is in a semi-dried state like a solvent-based adhesive. It exhibits a stringing state and has good contact properties. Further, the adhesive of the present invention, when adhered by one-side coating, the adhesion speed is the same as or faster than that of the solvent-type adhesive, when adhered by both-side coating, chloroprene rubber-based solvent It has good contact properties that are the same as or better than those of mold adhesives, has a long open time, and has very good workability. As described above, the water-based contact adhesive of the present invention has a high drying rate, excellent initial adhesive strength, extremely good contact properties and adhesive properties comparable to those of a solvent type, and further, does not contain an organic solvent. It does not harm the environment and there is no danger of fire.

Claims (9)

[Claims] 1. An acid value of 100 in a chloroprene rubber latex alone or in a mixed solution of a chloroprene rubber latex and another polymer emulsion, which is stable in the presence of an alkaline substance in at least a pH range of 6.5 to 8.0. An aqueous contact adhesive obtained by directly adding the above tackifying resin without dissolving it in a solvent in advance and dissolving and mixing in these liquids. 2. The tackifying resin having an acid value of 100 or more is rosin, polymerized rosin, hydrogenated rosin, dibasic acid modified rosin,
The water-based contact adhesive according to claim 1, which is at least one resin selected from the group consisting of a styrene-maleic acid copolymer resin and a maleic acid resin. 3. The water-based contact adhesive according to claim 1, wherein the tackifying resin having an acid value of 100 or more is an acrylic resin. 4. The water-based contact adhesive according to claim 2, wherein the dibasic acid-modified rosin is a maleic acid-modified rosin. 5. A rubber component 1 of chloroprene rubber latex.
The water-based contact adhesive according to claim 1, wherein the tackifying resin having an acid value of 100 or more is 10 to 250 parts by weight with respect to 00 parts by weight. 6. The aqueous contact according to claim 1, wherein the chloroprene rubber latex is a latex obtained by copolymerizing chloroprene and an ethylenically unsaturated carboxylic acid copolymerizable with chloroprene in the presence of polyvinyl alcohol. adhesive. 7. The chloroprene rubber latex is a latex obtained by copolymerizing chloroprene and an ethylenically unsaturated carboxylic acid copolymerizable with chloroprene in the coexistence of polyvinyl alcohol and glycol ethers. The water-based contact adhesive described. 8. The aqueous contact adhesive according to claim 1, wherein the other polymer emulsion is at least one selected from the group consisting of an acrylic resin emulsion and an emulsion of a tackifying resin having an acid value of 100 or less. 9. The water-based contact adhesive according to claim 1, wherein the total of the resin content and the rubber content is 50% or more.