JP2001011363A - Moistureproofing latex for construction board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject latex comprising a vinylidene chloride-based copolymer resin, capable of exhibiting high moistureproofness at low coating levels when applied to building internal trim materials or sheathing materials and having enough blocking resistance to be required in line coating operations. SOLUTION: This latex comprising a vinylidene chloride-based copolymer resin is obtained by emulsion polymerization of a monomer mixture comprising 85.0-93.0 wt.% of a vinylidene chloride monomer and 2.0-14.5 wt.% of at least one kind of another vinyl-based monomer copolymerizable therewith in the presence of 0.5-5.0 wt.% of a reactive emulsifier. This latex thus obtained has a surface tension of 50-70 mN/m.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latex comprising a vinylidene chloride-based copolymer resin for imparting moisture resistance by applying it to a building interior material or a building exterior material such as a ceiling or a wall. Further, the latex of the present invention
It has excellent blocking resistance.

[0002]

2. Description of the Related Art In recent years, the use of architectural boards has increased due to the increase in dry construction methods that do not use water at the site. As such boards, various types of building boards such as wood-based materials, gypsum board-based, asbestos slate-based, and composite panel-based boards are used. These building boards include:
There are problems such as warpage and dimensional change due to moisture absorption. For example, taking a silica plate as an example, asbestos cement calcium silicate plate, which is a kind of asbestos slate system, a so-called silica plate, is mainly made of cement, asbestos, lime and silicate materials, There is a problem that the rate is large, and in a humid place, warping is caused by moisture. There is a demand for prevention of warping around water such as bathrooms and kitchens in general houses. However, a coating exhibiting good moisture resistance has not been found. In addition, there is a similar problem in building exterior materials. Architectural exterior materials may undergo dimensional changes or warp due to moisture absorption. However, no effective coatings exhibiting good moisture barrier properties have been found.

[0003] On the other hand, vinylidene chloride copolymer resin latex is used for food packaging or industrial polypropylene, because of the excellent moisture-proof properties of the film obtained from the latex.
Widely used for plastic films such as polyester and nylon, and for coating materials such as cellophane and paper. Utilizing such properties, Japanese Patent Application Laid-Open No. 60-234838 proposes a method of coating a wooden building material with a latex of vinylidene chloride to improve moisture resistance. However, this method has a problem that the vinylidene chloride resin has to be thickly coated, which is costly. Similarly, Japanese Patent Application Laid-Open No. 60-65848 for building members and Japanese Patent Application Laid-Open No. 61-236669 for concrete,
For gypsum board, see JP-A-62-29653,
There has been proposed a method of improving the moisture-proof property by coating each with a vinylidene chloride latex. However, both methods must coat the vinylidene chloride resin thickly,
There was a problem that the cost was high.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a vinylidene chloride-based copolymer resin latex which exhibits good moisture resistance at a low coating amount and has sufficient blocking resistance required for line coating. It is intended to provide a building material having:

[0005]

Means for Solving the Problems In view of the above problems, the present inventors have made intensive studies, and as a result, surprisingly, a chloride having a specific surface tension and using a reactive emulsifier during polymerization was used. The present inventors have found that a vinylidene copolymer resin latex exhibits excellent moisture-proof performance even at a low coating amount, and have accomplished the present invention.

That is, the present invention is as follows. 1) A monomer mixture comprising 85.0 to 93.0% by weight of a vinylidene chloride monomer and 2.0 to 14.5% by weight of one or more other vinyl monomers copolymerizable therewith, A latex comprising a vinylidene chloride copolymer resin obtained by emulsion polymerization in the presence of 0.5 to 5.0% by weight of a reactive emulsifier, and having a surface tension of 50 to 70 mN / m
A latex for moisture-proofing a building board, characterized in that: 2) The latex for moisture-proofing a building board according to 1) above, which has a solid content of 15 to 45%. 3) A building board coated with the building board moisture-proof latex according to 1) or 2).

Hereinafter, the present invention will be described in detail. The amount of the vinylidene chloride monomer in the latex comprising the vinylidene chloride copolymer resin of the present invention is suitably from 85.0 to 93.0% by weight. If the content is less than 85.0% by weight, the crystallinity is low, and the moisture-proof property and the blocking resistance, which are the objects of the present invention, cannot be exhibited. On the other hand, if the content exceeds 93.0% by weight, crystallization of the copolymer resin proceeds even immediately after polymerization, so that latex particles become hard and film formability becomes poor. Preferably 8
8.0 to 92.0% by weight, and more preferably 89.
It is in the range of 0 to 92.0% by weight.

The vinyl monomers copolymerizable with vinylidene chloride used in the latex comprising the vinylidene chloride copolymer resin of the present invention include, for example, methyl acrylate,
Examples include alkyl ester monomers of ethylenic α, β-unsaturated carboxylic acids such as propyl acrylate, butyl acrylate, and methyl methacrylate. In addition, for example, a monomer having a nitrile group such as acrylonitrile or methacrylonitrile is also exemplified. Also, hydroxyalkyl esters of ethylene α, β-unsaturated carboxylic acids such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate; ethylene α, such as glycidyl acrylate and glycidyl methacrylate; amide compounds of ethylenic α, β-unsaturated carboxylic acids such as alkyl esters containing β-unsaturated carboxylic acid epoxy groups and acrylamide; vinyl esters such as vinyl chloride and vinyl acetate; vinyl ethers such as vinyl methyl ether; Examples thereof include allyl ethers such as allyl ester and allyl methyl ether, and styrene compounds. Further, unsaturated carboxylic acid-containing vinyl monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid are also included.

The amount of the vinyl monomer copolymerizable with vinylidene chloride is from 2.0 to 14.5% by weight. If it is less than 2.0% by weight, the film-forming properties will be poor. In addition, 14.5% by weight
If it exceeds 300, the moisture-proof property and the blocking resistance which the present invention aims at cannot be exhibited. It is preferably in the range of 4.0 to 11.0% by weight, and more preferably in the range of 5.0 to 10.0% by weight. By using a reactive emulsifier when emulsion-polymerizing the vinylidene chloride-based copolymer resin latex of the present invention, penetration into the base material is reduced, and good moisture resistance can be achieved with a low coating amount. As the reactive emulsifier, sodium salt of sulfoethyl methacrylate, α
-Sulfo-ω- (1- (nonylphenoxy) methyl-2- (2-propenyloxy) ethoxy) ammonium or sodium salt of poly (oxy-1,2-ethanediyl), sodium alkyl allyl sulfosuccinate, styrene sulfonic acid And sodium salts.

The amount of the reactive emulsifier is 0.5 to 5.0% by weight.
Range. If the amount is less than 0.5% by weight, stability during emulsion polymerization is poor, and a stable latex cannot be obtained. If the content exceeds 5% by weight, the amount of the hydrophilic substance in the coating film increases, and the moisture-proof property intended by the present invention cannot be exhibited. Preferably it is 1.0-4.0 weight%, More preferably, it is the range of 1.0-3.0 weight%. The vinylidene chloride copolymer resin latex of the present invention has a surface tension of 50.
It needs to be ７０70 mN / m. If it is less than 50 mN / m, a large amount of coating is required because the amount of permeation into the base material increases and sufficient moisture-proof properties cannot be exhibited. If it exceeds 70 mN / m, repelling may occur during coating, or the stability may be reduced. Therefore, aggregates may be generated due to poor mechanical stability during coating, and good moisture-proof properties may not be exhibited. Preferably the surface tension is 5
2 to 69 mN / m, more preferably 5 to
It is in the range of 4-68 mN / m.

The solid content of the vinylidene chloride copolymer resin latex of the present invention is preferably 15 to 45% by weight. If it is less than 15% by weight, the amount of evaporated water at the time of drying increases, and it takes time to finish the drying, so that the amount of permeation into the substrate increases, so that sufficient moisture-proof properties may not be exhibited. If the content exceeds 45% by weight, a coating film formed by permeation into the substrate becomes thin and cannot necessarily exhibit sufficient moisture-proof properties, so that a large amount of coating may be required. The types of the polymerization initiator, the surfactant, and the like used in the vinylidene chloride copolymer resin latex for dampproofing the building board of the present invention are not particularly limited.

The vinylidene chloride copolymer resin latex for building boards of the present invention may be used, if necessary, with various components generally used, such as defoaming agents, rheology modifiers, and thickeners. , A dispersant, a stabilizer such as a surfactant, a wetting agent, a plasticizer, a coloring agent, a wax, and a silicone oil. In addition, the vinylidene chloride copolymer resin latex for moisture prevention of building boards of the present invention can be used by blending pigments such as kaolin, talc, calcium carbonate, titanium dioxide, and aluminum hydroxide, if necessary. It is.

The architectural board coated with the vinylidene chloride copolymer resin latex of the present invention includes wood board such as particle board, fiber board, gypsum board board, asbestos cement calcium silicate board (silica board). And other asbestos slate boards, ALC panels, and various ceramic exterior building materials. As a method of applying the vinylidene chloride copolymer resin latex for building board moisture-proofing of the present invention, a known method such as an air knife coater, a bar coater, a blade coater, a roll coater, a gate roll coater, a cast coater or the like may be used. it can. Drying after application is performed in the range of 80 to 190 ° C for 20 minutes.
It is preferable to carry out for 5 seconds to 5 minutes.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to examples and the like. In the examples, “parts” means “parts by weight”.

Example 1 A vinylidene chloride copolymer resin latex was produced by the following method. 100 parts of water, 0.20 part of sodium dodecylbenzenesulfonate and 0.1 part of sodium persulfate were charged into a pressure-resistant reactor lined with glass, and after degassing, the temperature of the contents was kept at 55 ° C. Was.
In a separate container, 91 parts of vinylidene chloride (VDC), 4 parts of acrylonitrile (AN), and butyl acrylate (B
A) 3.5 parts were weighed and mixed to prepare a monomer mixture. Two parts of the monomer mixture were added all at once into the pressure-resistant reactor and polymerized until the internal pressure dropped. Subsequently, 96.5 parts of the monomer mixture were continuously metered in over 12 hours. In parallel, 1.5 parts of the sodium salt of sulfoethyl methacrylate were also continuously metered in over 10 hours. During this time, the content was maintained at 55 ° C., and the reaction was allowed to proceed until the internal pressure was sufficiently reduced. The polymerization yield is 99.9
%Met. Since the polymerization yield is almost 100%, the composition of the copolymer is almost equal to the charge ratio.

A 15% aqueous solution of sodium alkylsulfonate was added to the thus obtained latex to adjust the gas-liquid surface tension at 20 ° C. to 55 mN / m. Then, after removing the unreacted monomer by steam stripping, the solid content was adjusted to 40%. Next, the obtained latex was roll-coated to obtain a bulk density of 1.0 calcite plate (NA Lux thickness: 6 mm; manufactured by Nichias Corporation).
Is coated on the back surface so as to have a solid content of 30 g / m ^2.
It was dried at 30 ° C. for 90 seconds. Table 2 shows the evaluation results of the silicone plate coated with the latex. In addition, the evaluation method of a coating film is as follows.

(A) Blocking resistance The coated surface of a silicone plate coated with the moisture-proof water-based coating composition obtained above was treated at 35 ° C. and a relative humidity of 90 by a method according to JIS-Z-5400 (anti-adhesion). %, 40 g / cm ²
Then, the gauze after standing for 18 hours is peeled off from the coated surface, and the area after the cloth is examined. (B) Moisture Proof Property The moisture permeability of the caliper board coated with the moisture-proof aqueous coating composition obtained above was measured according to JIS-Z-0208 (cup method). The measurement conditions are 40 ° C. and 90% RH.

[0017]

Examples 2 to 4 Table 1 shows the monomer composition in Example 1.
After obtaining a latex by the same method as in Example 1 except that the change was made as shown in Table 1, evaluation of the squeezing plate was performed by the same method as in Example 1. The results are shown in Table 2.

Example 5 The monomer composition in Example 1 was changed as shown in Table 1, and the reactive emulsifier used was α-sulfo-
A latex was obtained in the same manner as in Example 1, except that ω- (1- (nonylphenoxy) methyl-2- (2-propenyloxy) ethoxy) poly (oxy-1,2-ethanediyl) ammonium salt was used. Then, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0018]

Example 6 The monomer composition in Example 1 was changed as shown in Table 1, and the surface tension of the latex was 53 mN / m.
It was adjusted to be. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 7 The monomer composition in Example 1 was changed as shown in Table 1, and the surface tension of the latex was changed to 70 mN / m.
It was adjusted to be. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0019]

Example 8 The monomer composition in Example 1 was changed as shown in Table 1, and the surface tension of the latex was 53 mN / m.
Was adjusted so that Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 9 The monomer composition in Example 1 was changed as shown in Table 1, and the surface tension of the latex was 53 mN /
m, and the solid content of the latex was adjusted to 44%. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0020]

Example 10 After a latex was polymerized in the same manner as in Example 1, the solid content of the latex was adjusted to 50%. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 11 The monomer composition in Example 1 was changed as shown in Table 1, and the solid content of the latex was adjusted to 55%. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0021]

Comparative Examples 1 and 2 Table 1 shows the monomer composition in Example 1.
A latex was prepared in the same manner as in Example 1, except that the latex was changed. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 3 The monomer composition in Example 1 was changed as shown in Table 1, and the surface tension of the latex was changed to 40 mN / m.
It was adjusted to be. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 4 The monomer composition in Example 1 was changed as shown in Table 1, and the latex had a surface tension of 72 mN /
m and the solid content of the latex were adjusted to 15%. Next, the calcical plate was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

From the results of the above examples, the moisture-proof latex for building boards comprising the vinylidene chloride-based copolymer resin latex of the present invention is excellent in moisture resistance, excellent in blocking resistance and extremely useful. . In addition, since it exhibits high moisture proofing at a low coating amount, it can provide moisture proofing at low cost.

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Claims (3)

[Claims] 1. The method according to claim 1, wherein the vinylidene chloride monomer is 85.0-9.
A monomer mixture consisting of 3.0% by weight and 2.0 to 14.5% by weight of one or more other vinyl monomers copolymerizable therewith is mixed with 0.5 to 5.0% by weight of a reactive emulsifier. Is a latex made of a vinylidene chloride copolymer resin obtained by emulsion polymerization in the presence of
A latex for moisture-proofing architectural boards, wherein the latex is mN / m. 2. The latex for building boards according to claim 1, wherein the latex has a solid content of 15 to 45% by weight. 3. A building board coated with the building board moisture-proof latex according to claim 1 or 2.