JP2000129063A - Vinylacetate-based-resin emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which shows excellent film formability at a low temperature, adhesion, water resistance or a mechanical property by forming a vinylacetate-based emulsion containing a diol having a specific carbon number. SOLUTION: A vinylacetate-based resin emulsion containing a resin content of 20-70 wt.% contains not less than one compounds of 7-10C diols and a plastisizer such as dibutylphthalate, the total thereof being 1-10 pts.wt. per 100 pts.wt. of the resin component of the emulsion. The 7-10 C diol includes 2-ethyl-3-propyl-1,5-pentanediol and the like and an 8-9 C diol includes 2-ethyl-1,3- hexanediol, 2,4-diethyl-1,5-pentanediol and the like. The vinylacetate-based resin includes a homopolymer of vinylacetate alone and a copolymer of 20-95 wt.% of vinylacetate and a copolymerizable monomer such as (meth)acrylic acid, methylacrylate, dibutylmaleate, glycidylmethacrylate and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl acetate resin emulsion used for water-based adhesives, water-based paints and the like. In addition, it is possible to reduce a decrease in water resistance.

[0002]

2. Description of the Related Art Vinyl acetate resin emulsions are inexpensive and have relatively good adhesiveness and weather resistance, and thus are widely used as adhesives for wood and paper, paints and caulks.

[0003] Vinyl acetate resin emulsions have a high film-forming temperature of 15 to 20 ° C, and do not proceed in a low-temperature environment such as a cold region or winter, and exhibit necessary mechanical properties and adhesiveness. There are no drawbacks.

For this reason, in order to lower the film forming temperature to about 2 ° C. or lower and enable use in a low-temperature environment, dibutyl phthalate (DBP), diheptyl phthalate (DHP) or dimethyl phthalate has been conventionally used. It is practically used after blending a plasticizer such as (DMP) or a high boiling solvent such as cellosolve, cellosolve acetate or phenols.

[0005] Generally, among these plasticizers,
DBP is mainly used in terms of cost, odor, etc., and at least 10 parts by weight of DBP is added to 100 parts by weight of the resin component of the vinyl acetate resin emulsion, and the film forming temperature is lowered to 2 ° C. or less. I have.

However, when a large amount of dibutyl phthalate is added, the vinyl acetate resin itself is highly plasticized, the cohesive strength of the resin is reduced, and the adhesive strength, especially at high temperatures, is greatly reduced. In addition, disadvantages such as reduced water resistance appear (Japanese Patent Publication No. 46-28653).

[0007] To overcome such disadvantages, glycol phenyl ethers such as polypropylene glycol phenyl ether (JP-B-46-35493) and glycol diacetates (JP-A-50-556).
No. 49), phenols (JP-B-46-28653).
Publication) or adding a plasticizer such as a polyhydric alcohol.

More specifically, polyhydric alcohols such as ethylene glycol, propylene glycol, triethylene glycol or hexylene glycol are used as plasticizers for vinyl acetate resin emulsions (Japanese Patent Publication No. 8-6003). ).

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vinyl acetate resin composition having excellent low-temperature film-forming properties, adhesiveness, water resistance and mechanical properties.

[0010]

This problem can be solved by including a diol having 7 to 10 carbon atoms in a vinyl acetate resin emulsion.

The addition amount of the diol is preferably 1 to 10 parts by weight based on 100 parts by weight of the resin component.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The diol having 7 to 10 carbon atoms used for lowering the film-forming temperature in the present invention is a compound comprising two hydroxyl groups and a linear or branched alkylene portion having 7 to 10 carbon atoms. For example, 2-ethyl-3-
Propyl-1,5-pentanediol is preferred, and those having 8 or 9 carbon atoms are preferable.
-Ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol or 2-butyl-2-
Ethyl-1,3-propanediol and the like.
When the number of carbon atoms is 6 or less, the film forming temperature effect is not sufficient. I do.

These diols are used as one kind or a mixture of two or more kinds, but may be used in combination with other plasticizers. Here, as another plasticizer, for example, dibutyl phthalate (DBP), 2,2,4-trimethyl-
1,3-pentanediol monoisobutyrate (Texanol) and the like. When other plasticizers and solvents are used in combination, the total amount of the diol and the plasticizer used is 10% of the resin content.
The amount is preferably 1 to 10 parts by weight with respect to 0 parts by weight.

As the diol, commercially available products can be purchased. For example, 2,4-diethyl-1,5-pentanediol and the like can be obtained by synthesis according to the method described in JP-A-8-48642. May be. Also, 2-ethyl-
3-propyl-1,5-pentanediol and the like can be synthesized by the method described in JP-A-5-262859.

As the vinyl acetate resin emulsion,
A homopolymer composed of a vinyl acetate monomer alone or a copolymer composed of a monomer copolymerizable with vinyl acetate is used. Hereinafter, the above homopolymers and copolymers may be referred to as vinyl acetate resins.

Examples of copolymerizable monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dibutyl maleate, methyl methacrylate, ethyl methacrylate, butyl methacrylate,
-Ethylhexyl methacrylate, glycidyl acrylate, glycidyl methacrylate, ethylene glycol monoacrylate, ethylene glycol monomethacrylate, propylene glycol monoacrylate, propylene glycol monomethacrylate, ethylene glycol dimethacrylate and the like are used.

The vinyl acetate content in the copolymer is from 20 to 95.
Preferably, it is weight%.

In the present invention, for example, polyvinyl acetate (PVA) is used as a protective colloid in the presence of a polymerization initiator such as ammonium persulfate, potassium persulfate, hydrogen peroxide or the like, or vinyl acetate alone or the above copolymer with vinyl acetate. An emulsion obtained by emulsion polymerization of a possible monomer with water can be used, or a commercially available emulsion may be used as it is. When performing emulsion polymerization, an emulsifier may be used, and a known anionic emulsifier, cationic emulsifier, nonionic emulsifier and the like can be used. The amount of the emulsifier used is not particularly limited, but is usually 0.1 to 10% by weight based on the vinyl acetate resin.

In the preparation of the vinyl acetate resin emulsion, the conditions for the emulsion polymerization of the above monomers are not particularly limited, and known methods such as a polymerization temperature, a polymerization time, and a method for adding a monomer (for example, JP-A-9-40926) JP-A-8-6003 and Japanese Patent Publication No. 8-6003). The amount of the polymerization initiator used is preferably 0.05 to 4% by weight of the monomer. Further, the concentration of polyvinyl alcohol serving as a protective colloid is preferably in the range of 2 to 20% by weight based on the water of the dispersion medium. As the polyvinyl alcohol, those having a degree of polymerization of 100 to 4500 and a degree of saponification of 65 mol% or more are preferable from the viewpoint of the water resistance of the dried film.

The resin content in the vinyl acetate resin emulsion is preferably in the range of 20 to 70% by weight. The particle size of the emulsion is not particularly limited depending on the type and amount of the PVA or emulsifier, but is preferably about 0.1 to 1 μm.

The vinyl acetate resin emulsion of the present invention is produced by adding the diol to the vinyl acetate resin emulsion. The amount of the diol used is 1 to 10 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the resin component of the emulsion. If the amount is less than 1 part by weight, the effect of lowering the film-forming temperature cannot be obtained. If the amount exceeds 10 parts by weight, plasticization of the polymer itself becomes severe, cohesive strength is reduced, and adhesive strength, water resistance and the like are reduced.

As a specific method of incorporating the diol, there is a method of adding a predetermined amount of the diol to an emulsion and stirring the emulsion sufficiently.

In the vinyl acetate resin emulsion of the present invention, various additives may be added according to the use.

For example, when used as an adhesive, a filler such as calcium carbonate, talc or silica, a thickener such as methylcellulose or carboxymethylcellulose,
Preservatives, aqueous thermosetting resins such as urea resins, and the like may be added. Further, when used as a paint, a moisture-resistant pigment such as clay or calcium carbonate, a pigment such as titanium oxide or zinc oxide, a dispersant, a thickener, a preservative,
An antifoaming agent or a freeze stabilizer may be added.

In the vinyl acetate resin emulsion of the present invention, the addition amount of the diol for obtaining the effect of lowering the film forming temperature may be small, so that the plasticization of the vinyl acetate resin itself is suppressed and the aggregation by the diol is suppressed. The force does not drop significantly. For this reason, when used as an adhesive,
Usually, there is no decrease in adhesive strength and water resistance caused by the addition of a plasticizer, and when used as a paint, the coating film hardness,
Effects such as a decrease in weather resistance and adhesion are exhibited. Further, since the added amount of the diol is small, the vinyl acetate resin emulsion of the present invention has a low odor.

The adhesive of the present invention comprises a vinyl acetate resin emulsion containing the diol as a main component, to which the above additives are added as required.

Similarly, the paint of the present invention comprises a vinyl acetate resin emulsion containing the diol as a main component, to which the above-mentioned additives are added if necessary.

Examples of uses of the adhesive of the present invention include:
It is preferably used for woodwork such as decorative plywood, flash plywood or furniture, paper and packaging such as cardboard, bookbinding, bag making or paper boxes, or construction of flooring, vinyl tile, wallpaper or wall cloth. This adhesive is particularly useful as a low-temperature wood adhesive because it has good adhesion and water resistance even at low film forming temperatures.

Hereinafter, the operation and effect will be clarified by specific examples, but the present invention is not limited to these specific examples.

[0031]

Examples 1 to 5 (1) Example of polymerization of vinyl acetate resin emulsion In a reactor equipped with a stirrer, a thermometer and a dropping funnel, 125 parts by weight of water and PVA (Kuraray Poval PVA-11) were added.
7, Kuraray Co., Ltd .: saponification degree 98 mol%, polymerization degree 1
700) 11 parts by weight, and stir the contents.
VA was dispersed in water. Next, the dispersion is heated to a temperature of 95 ° C.
, And the same temperature was maintained for 1 hour to dissolve the PVA. Next, this PVA aqueous solution was cooled to 70 ° C., and 5 g of vinyl acetate monomer and 0.2 g of ammonium persulfate as a polymerization initiator were added thereto, and initial polymerization was performed for 15 minutes under a nitrogen atmosphere. Thereafter, 95 g of vinyl acetate and 0.4 g of ammonium persulfate were separately dropped, and the reaction was carried out for 3 hours. After completion of the reaction, the reaction solution was aged at 70 ° C. for 1 hour to obtain a vinyl acetate resin emulsion having a resin content of 47% by weight.

(2) Preparation of Adhesive Composition An adhesive composition was obtained by adding 3 to 5 parts by weight of the diol described in Table 1 to 100 parts by weight of the resin component of this vinyl acetate resin emulsion. .

(3) Test Results The minimum film forming temperature and compression shear test (normal test, water resistance test) were measured in accordance with JIS 6804 standard of vinyl acetate resin emulsion wood adhesive. Table 1 shows the results.

[0034]

[Table 1] From Table 1, it is recognized that the adhesive comprising the vinyl acetate resin emulsion of the present invention has good film-forming properties at low temperatures, and also has excellent adhesive strength and water resistance.

[0035]

As described above, the vinyl acetate resin emulsion of the present invention contains a diol having 7 to 10 carbon atoms, and by using a small amount of the diol, the emulsion is formed into a film. The temperature can be sufficiently lowered, and furthermore, the plasticization of the vinyl acetate resin itself is suppressed, and the decrease in the cohesive force of the resin itself is small. Further, the odor of the emulsion is reduced.

For this reason, the adhesive comprising the vinyl acetate resin emulsion has good adhesiveness and water resistance,
The bonding operation can be performed even at a low temperature.

Further, the coating composition comprising the vinyl acetate resin emulsion can be applied even at a low temperature, has a high coating film hardness, and has good weather resistance and adhesion.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C09J 131/04 (72) Inventor Taiji Yamamoto 2-3-3 Daikyocho, Yokkaichi-shi, Mie Kyowa Yuka F term in Yokkaichi Research Laboratory (reference) 4F070 AA28 AA29 AA32 AC36 AE02 CA02 FA05 FB05 4J038 CF021 JA20 MA08 MA10 NA04 NA24 PB02 4J040 DE021 HB10 JA03 LA06 LA07

Claims (6)

[Claims] 1. A vinyl acetate resin emulsion containing a diol having 7 to 10 carbon atoms. 2. The vinyl acetate resin emulsion according to claim 1, wherein the diol has 8 or 9 carbon atoms. 3. The diol having 8 or 9 carbon atoms is 2-ethyl-1,3-hexanediol, 2,4-diethyl-diol.
The vinyl acetate resin emulsion according to claim 2, which is 1,5-pentanediol or 2-butyl-2-ethyl-1,3-propanediol. 4. The method according to claim 1, wherein the resin content is 100 parts by weight.
The vinyl acetate resin emulsion according to claim 1, wherein the diol is contained in an amount of 1 to 10 parts by weight. 5. An adhesive comprising the vinyl acetate resin emulsion according to claim 1. 6. A coating comprising the vinyl acetate resin emulsion according to claim 1.