JPH07108968B2 - Adhesive composition for wood flooring - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition for wood flooring.

(Prior Art) Conventionally, a polyvinyl acetate solution-type adhesive composition has been generally used as an adhesive composition for wood flooring. Further, recently, with the movement of desolvation, the shift to water-based type has progressed, and polyvinyl acetate water-based emulsion type adhesive compositions have been partially used.

(Problems to be Solved by the Invention) However, for example, when a wooden flooring material (such as Super 6: Asahi Woodtech Co., Ltd.) is adhered onto a particle board, a polyvinyl acetate water-based emulsion type adhesive composition is used as an adhesive agent. Sufficient adhesive strength can be obtained by using objects, but when people move on the floor after installation, noise is generated mainly due to contact / detachment of the adhesive layer (so-called floor ringing phenomenon). The inconvenience occurs. Also, when using a polyvinyl acetate solution-type adhesive composition as an adhesive, sufficient adhesive strength is obtained and at the same time the floor squeal phenomenon does not occur after the application, but due to the volatilization of the solvent during the adhesive coating operation. This causes the inconvenience that there is a risk of contamination of the work environment and ignition and explosion.

The present invention has been made in view of such circumstances, and obtains sufficient adhesive strength.

Floor noise does not occur after construction.

There is no danger of work environment contamination or ignition explosion due to solvent volatilization during adhesive coating work.

It is an object of the present invention to provide an adhesive composition for wood flooring that simultaneously satisfies the above items (1) to (3).

(Means for Solving the Problems) The adhesive composition for a wood flooring material of the present invention comprises an (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, or an ethylenic compound copolymerizable therewith. It is a (co) polymer of a mixture with an unsaturated monomer, and the calculated value of the glass transition temperature (hereinafter referred to as Tg) of the mixture (co) polymer is −.
A copolymer of a mixture of an inner layer (I) having a temperature of 10 ° C. or less, a polyvinyl monomer and an ethylenically unsaturated monomer copolymerizable therewith, which is polymerized in the absence of the inner layer (I). In this case, the mixture copolymer contains a water-based copolymer emulsion composed of particles having a two-layer structure with the outer layer (II) having a calculated Tg value of 50 ° C. or higher.

The inner layer (I) has an alkyl group having 1 to 18 carbon atoms (meth)
Acrylic alkyl ester homopolymer or a (co) polymer of a mixture with an ethylenically unsaturated monomer copolymerizable therewith, wherein the calculated Tg of the mixture (co) polymer is -10 ° C or less. is there.

Preferred among the (meth) acrylic acid alkyl esters are ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

Examples of the ethylenically unsaturated monomer include the following monomers (a) to (j).

(A) Aromatic hydrocarbon monomer which may be substituted: Styrene, alkyl group-substituted styrene (α-methylstyrene, p-methylstyrene, vinyl-toluene, etc.), halogen-substituted styrene (monochlorostyrene, etc.).

(B) Nitrile group-containing monomer: (meth) acrylonitrile and the like.

(C) Halogen-containing monomer: vinyl chloride, vinylidene chloride, chloroprene, etc.

(D) Aliphatic hydrocarbon monomer: ethylene, propylene, butadiene, isoprene and the like.

(E) Vinyl ester or (meth) allyl ester: Vinyl acetate, vinyl propionate, allyl acetate and the like.

(F) Unsaturated carboxylic acid ester: diester or half-ester of maleic acid, fumaric acid or itaconic acid.

(G) Hydroxyl group-containing monomer: hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and the like.

(H) Sulfone group-containing monomer: vinyl sulfonic acid (salt), (meth) allyl sulfonic acid (salt), styrene sulfonic acid (salt), etc.

(I) Amino group-containing monomer: (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate and the like.

(J) Unsaturated carboxylic acid (salt): (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid and the like, and salts thereof (alkali metal salt, ammonium salt, amine salt, etc.) and the like.

Preferred among (a) to (j) is vinyl acetate.

These monomers (a) to (j) are used, if necessary, as a mixture of one or more of them with a (meth) acrylic acid alkyl ester, and the use ratio in the inner layer (I) is (a), There are no particular restrictions on (b), (c), (d) or (e), but (f), (g), (h),
When (i) or (j) is used, it is usually the inner layer (I)
It is 0.1 to 10% by weight.

The calculated Tg of the mixture copolymer constituting the inner layer (I) is -10 ° C.
It is the following. If the calculated Tg is higher than -10 ° C, sufficient adhesive strength will not be imparted.

Note that the calculated Tg in the present specification refers to the Tgc calculated by the equation (1) expressed in degrees Celsius (° C).
(Source: Fox et al; Bull.Am.Physics Soc., 1,3.P123
(1956)) (Wherein W1:% by weight of monomer 1 in (co) polymer W2:% by weight of monomer 2 in (co) polymer W3:% by weight of monomer 3 in (co) polymer % By weight Tg1: Absolute temperature of glass transition temperature of homopolymer of monomer 1 Tg2: Absolute temperature of glass transition temperature of homopolymer of monomer 2 Tg3: Monomer 3 The glass transition temperature of the homopolymer of Tgc: (co) polymer is represented by the absolute temperature. The outer layer (II) is a polyvinyl monomer and A copolymer of a mixture with a copolymerizable ethylenically unsaturated monomer, which has a calculated Tg of 50 ° C or higher when the mixture is polymerized in the absence of the inner layer (I). .

As the polyvinyl monomer, divinyl monomer (divinylbenzene, divinyl phthalate, diallyl phthalate,
1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate diethylene glycol, di (meth) acrylate, etc., trivinyl monomer (trimethylolpropane tri (meth)) Acrylate,
Glycerin tri (meth) acrylate, etc., tetravinyl monomer (pentaerythritol tetra (meth) acrylate, etc.), hexavinyl monomer (dipentaerythritol hexa (meth) acrylate, etc.), and the like are preferable. Benzene, 1,6-hexanediol di (meth) acrylate and diethylene glycol, di (meth) acrylate.

As the ethylenically unsaturated monomer, the above (a) to
The monomer of (j) and methyl methacrylate,
Preferred are styrene and methyl methacrylate. These (a) to (j) monomers may be used alone or in combination of two or more as a mixture with the above-mentioned polyvinyl monomer, but (f), (g), (h), (i) or When (j) is used, it is not used in one kind but is used in two or more kinds with other (a), (b), (c), (d) or (e), and its use The ratio is usually 0.1 in the outer layer (II)
~ 10% by weight. The proportion of polyvinyl monomer used is usually 0.1 to 15% by weight. The calculated Tg of the mixture copolymer constituting the outer layer (II) is 50 ° C. or higher when polymerized in the absence of the inner layer (I). If the calculated Tg is lower than 50 ° C, the floor squeal phenomenon after construction is likely to occur.

The amount of the inner layer (I) and the outer layer (II) is usually 5 to 95% by weight for (I) and 95 to 5 for (II) based on the total of (I) and (II).
%, Preferably (I) is 75 to 25% by weight (I
I) is 25-75% by weight. When (I) is less than 5% by weight and (II) exceeds 95% by weight, sufficient adhesive strength is not imparted, (I) exceeds 95% by weight, and (II) is 5% by weight. If it is less than the above, the floor squeal phenomenon after construction is likely to occur.

The two-layer structure particles of the inner layer (I) and the outer layer (II) are usually
It has an average particle size of 0.05 to 2 μm.

The aqueous copolymer emulsion in the present invention is obtained by a known emulsion polymerization method. Particularly preferred is the sheet emulsion polymerization method. First, the (meth) acrylic acid alkyl ester to be the inner layer (I) alone or in a mixture is polymerized by a usual emulsion polymerization method (collective charging method, monomer dropping method, emulsion dropping method, etc.). Emulsifiers used for emulsion polymerization include: a) Anionic emulsifiers: sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, ammonium polyoxyethylene alkyl ether sulfate, alkylallyl sulfosuccinate, polyoxy Propylene (meth) acrylate sodium sulfate, etc.

B) Nonionic emulsifier: polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, polypropylene glycol ethylene oxide adduct, etc.

C) Cationic emulsifiers: stearylbenzyldimethylammonium chloride, distearyldimethylammonium chloride, etc.

Etc. and mixtures of two or more thereof. The amount of the emulsifier used is usually the amount based on the mixture of the inner layer (I).
It is 0.1 to 8% by weight.

Initiators used for emulsion polymerization include: d) Persulfates: potassium persulfate, ammonium persulfate, etc.

E) Peroxide compounds: Benzoyl peroxide, lauroyl peroxide, hydrogen peroxide, etc.

F) Redox initiators: Sulfite and peroxide compounds, hydrogen peroxide and Fe ^2+, etc.

And so on. The polymerization temperature is usually 30 to 100 ° C.

Subsequently, in the presence of the inner layer (I), a new emulsifier was not added (if necessary, the addition amount is limited to a range that does not generate new particles consisting of the outer layer (II) component),
A water-based copolymer emulsion can be obtained by dropping the mixture to form the outer layer (II) and continuing the polymerization.

The adhesive composition for a wood flooring material of the present invention contains the water-based copolymer emulsion, and it is a commonly known filler (clay, calcium carbonate, talc, etc.), natural adhesive (starch, natural rubber-based adhesive). Resin, etc.), synthetic adhesive (polyvinyl alcohol, polyvinyl pyrrolidone, acrylic resin, synthetic rubber resin, etc.), tackifier (terpene resin, etc.), film forming aid (ethylene glycol, dibutyl phthalate, ethyl cellosolve, ethyl carbi) Etc.), a thickener, a dispersant, a defoaming agent, an antiseptic and a deterioration inhibitor, etc., and are used as an adhesive composition.

(Examples) Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. In addition, below, a part represents a weight part.

[Production of water-based copolymer emulsion]

Production Example 1 Stirrer, dropping funnels (A), (B), nitrogen gas inlet,
200 parts of water in a reaction vessel equipped with a thermometer and a reflux condenser,
1 part of potassium persulfate, 0.4 part of sodium hydrogen carbonate, 1 part of sodium lauryl sulfate and 1 part of polyoxyethylene nonyl phenyl ether were charged, the system was replaced with nitrogen gas under stirring, and the temperature was raised to 70 ° C. Monomer (mixture of 2-ethylhexyl acrylate / vinyl acetate / acrylic acid = 75/23/2 parts) from the dropping funnel (A) at the same temperature 1
After adding 20 parts dropwise over 1 hour and reacting for another 2 hours, 1 part of 80 parts monomer (a mixture of styrene / divinylbenzene = 95/5 parts) was added from the dropping funnel (B) at the same temperature.
The solution was added dropwise over a period of time, and the reaction was continued for 1 hour. The reactants
The mixture was cooled to 30 ° C., adjusted to pH 7 with 25% ammonia water, and filtered through a 150-mesh wire mesh to obtain an aqueous copolymer emulsion having a solid content of 50.4% and an average particle diameter of 0.35 μm.

Production Examples 2 to 8 In the same manner as in Production Example 1, the monomers and the monomers were replaced by the monomers described in Production Examples 2 to 8 in Table 1 and reacted to give an aqueous copolymer emulsion. Obtained.

Comparative Production Example 1 In the same manner as in Production Example 1, instead of the monomer in Production Example 1, 2-ethylhexyl acrylate / vinyl acetate /
An aqueous copolymer emulsion was obtained using a mixture of acrylic acid = 32/66/2 parts. (Calculation of Inner Layer (I) Tg = 0 ° C.) Comparative Production Example 2 In the same manner as in Production Example 1, instead of the monomer in Production Example 1, a mixture of styrene / lauryl methacrylate = 70/30 parts was used. A water-based copolymer emulsion was obtained. (Calculation of outer layer (II) Tg = 28 ° C.) Comparative Production Example 3 A method similar to that of Production Examples 1 to 8 was used, but the monomer and the monomer were not distinguished, and acrylic acid 2- Ethylhexyl / vinyl acetate / acrylic acid = 75/23 /
An aqueous copolymer emulsion was obtained using 300 parts of the mixture of 2 parts.

Comparative Production Example 4 In the same manner as in Comparative Production Example 3, 300 g of a mixture of styrene / divinylbenzene = 95/5 parts was used as a monomer to obtain an aqueous copolymer emulsion.

Comparative Production Example 5 In the same manner as in Comparative Production Examples 3 and 4, as a monomer,
300 parts of a mixture of 2-ethylhexyl acrylate / vinyl acetate / acrylic acid / styrene / divinylbenzene = 45 / 13.8 / 1.2 / 38/2 parts was used to obtain an aqueous copolymer emulsion.

Examples 1 to 8 and Comparative Examples 1 to 7 Water-based copolymer emulsions obtained in Production Examples 1 to 8 and Comparative Production Examples 1 to 5 and a polyvinyl acetate methanol solution (Esdyne # 1057: manufactured by Sekisui Chemical Co., Ltd.) ) A polyvinyl acetate emulsion (Esdyne # 5300: manufactured by Sekisui Chemical Co., Ltd.) was used to obtain an adhesive composition having the following formulation.

(Part) Emulsion or methanol solution 100 (solid content) Clay 20 Calcium carbonate 80 Talc 20 Ethylcarbitol 5 Hydroxyethyl cellulose 1 Sodium polyacrylate 0.5 Water or methanol Remaining amount (solid content of adhesive = 65%) The test results of the adhesive strength, the floor ringing property and the environmental pollution property of the adhesive compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 1 are shown.

Test method for each test item Adhesive strength: Approximately 300 g / m ² of adhesive is applied on particle board (100 x 25 mm) with an applicator, and after 15 minutes, Super 6 (100
× 25mm, Asahi Woodtech Co., Ltd.) adhesive area is 25 × 2
Laminated to 5m, fixed with a clip, 20 ℃ ×
After standing for 24 hours at 65% RH, measure shear tensile strength (pulling speed: 50 mm / min) with an Instron tester.

Floor noise: Approximately 300g / m ² of adhesive is applied on the particle board with spacers with a comb and then Super 6 is pasted at 20 ℃ × 65% R
After standing for 24 hours under the condition of H, riding on Super 6 and the presence or absence of floor ringing sound and the sound pressure level (dB (A)) at 2000 Hz of the generated sound are Type1015 + Type3303 (manufactured by JEIC Electronics Co., Ltd.) Measured at.

○: No ringing noise △: Slight ringing noise (45 to 60 dB (A)) ×: Flooring noise (61 to 75 dB (A)) Environmental pollution The presence or absence of solvent odor was judged by the sense of smell.

◯: No solvent odor X: Solvent odor (Effect of the invention) The adhesive composition for a wood flooring material of the present invention has the following effects. That is, when a wood flooring or the like is adhered on a particle board or the like, if the adhesive composition is used for construction, the solvent is not volatilized since it is water-based, and there is no risk of environmental pollution or ignition explosion.

Sufficient adhesive strength is obtained.

Even if people move on the floor after construction, so-called floor squeal does not occur.

The above-mentioned effects are simultaneously exhibited.

Claims (1)

[Claims] 1. A (co) polymer of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, or a mixture thereof with an ethylenically unsaturated monomer copolymerizable therewith. A mixture of an inner layer (I) in which the calculated glass transition temperature of the mixture (co) polymer is −10 ° C. or lower, and a polyvinyl monomer and an ethylenically unsaturated monomer copolymerizable therewith A water-based copolymer comprising a two-layer structure particle having an outer layer (II) having a calculated glass transition temperature of 50 ° C. or more when the mixture is polymerized in the absence of the inner layer (I). An adhesive composition for wood flooring, characterized by containing a copolymer emulsion.