JPH0379392B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an elastic coating composition that is highly stain resistant and capable of forming a film with good low-temperature elongation. It has been known to use emulsion compositions mainly composed of monomers that form soft polymers as binders for elastic paints, but elastic paints using such compositions as binders have Although it has excellent low-temperature elongation, it often has poor stain resistance, which often limits its range of use. Methods to improve this staining property include (1) making the copolymer harder by increasing the copolymerization amount of monomers that can form a polymer with a high glass transition temperature; Methods such as introducing a crosslinking group to achieve internal crosslinking have been adopted. However, if the copolymer is hardened as in (1), the film formed will naturally become hard and the stain resistance will be good, but it will have the disadvantage of lowering the low-temperature elongation required for elastic paints. However, improving the staining property by internal crosslinking as in (2) may result in a decrease in film elongation as a result of this crosslinking, and in addition, if the crosslinking density becomes excessive, film forming properties may also be reduced. , which leads to problems such as embrittlement of the film. However, as a result of intensive research in view of the above-mentioned difficulties and drawbacks of the prior art, the present inventors have discovered an elastic coating composition with excellent stain resistance and low-temperature elongation, and have developed the present invention. I have come to complete it. That is, in the present invention, each of the essential components has a solid content of 2 to 2, based on the total weight of the monomers.
In water, in the presence of 30% polyurethane latex and an emulsion dispersion stabilizer, 100 to 86% by weight of an α,β-ethylenically unsaturated monomer having no reactive polar groups and the reactive A reactive polar group-containing monomer that can be copolymerized with a polar group-free α,β-ethylenically unsaturated monomer (hereinafter abbreviated as “α,β-ethylenically unsaturated monomer”) 0-14% by weight of the body,
An object of the present invention is to provide an elastic coating composition comprising an emulsion composition containing a copolymer obtained by emulsion copolymerization using a radical-forming catalyst at a temperature of 0 to 100°C. . Here, the polyurethane latex used is different from the water-soluble polyurethane used.
This is because fine blocks occur during emulsion copolymerization, making it impossible to obtain a good emulsion.Also, there is a method of blending this polyurethane latex, but in this case, the difference in specific gravity makes it difficult to obtain a good emulsion. This is undesirable since it has disadvantages in that the storage stability of the elastic coating composition deteriorates and furthermore, the strength and elongation of the coating film after a water resistance test decreases. The polyurethane latex used in preparing the composition of the present invention has a number average molecular weight of
A polyurethane derived from a long chain glycol having a hydroxyl group at both ends of 300 to 3000, a polyisocyanate compound having an NCO group at both ends, and, if necessary, a chain extender having a reactive hydroxyl group. Aqueous dispersions are suitable. Here, representative long-chain glycols include polyether glycols obtained by polymerizing alkylene oxides such as propylene oxide or tetrahydrofuran; glycols such as adipic acid and ethylene glycol or propylene glycol; Examples include polyester glycols obtained by condensation with equols; polyester glycols obtained by polymerization of lactones. On the other hand, typical examples of the polyisocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate. Furthermore, the above-mentioned chain extenders are used as necessary in preparing polyurethane compounds, and examples of such chain extenders include polyhydric alcohols, amines, amino alcohols, water, etc. Specifically, ethylene glycol,
Examples include 1,4-butanediol, 1,6-hexanediol, ethanolamine, ethylenediamine or N,N'-dimethylpiperazine. In addition to these, anionic emulsifiers, nonionic emulsifiers, protective colloids, etc. are used as dispersants, but typical nonionic emulsifiers include polyethylene glycol, polyoxyethylene alkyl allyl ether, and polyoxyethylene alkyl ether. amide or polyoxyethylene-polyoxypropylene block copolymer, etc. Typical anionic emulsifiers include sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfate, or alkylaryl polyether sulfate; Typical colloids include polyvinyl alcohol, casein, methylcellulose, and hydroxyethylcellulose. These dispersants can be used alone or in combination of two or more. The amount of these dispersants used is preferably 0.05 to 10% by weight based on the polyurethane. If the amount used is less than 0.05% by weight, the stability of the resulting polyurethane latex will deteriorate and it will be difficult to form a good emulsion during emulsion polymerization, whereas if it exceeds 10% by weight. This is not preferable because the durability of the resulting latex will be poor. The polyurethane latex has a solid content of 2 to 30% based on the total weight of monomers as listed below.
It is preferable to use it within the range. If the amount used is less than 2% by weight, the effect of improving low-temperature elongation will not be obtained, and if it exceeds 30% by weight, the strength and elongation of the resulting paint after the water resistance test will decrease. Both are unfavorable. In addition, typical α,β-ethylenically unsaturated monomers used in preparing the composition of the present invention include methyl-, ethyl-, propyl-, n-butyl-, i-butyl, t-butyl, n-amyl, i-amyl, hexyl, octyl, nonyl, decyl, dodecyl, octadecyl, cyclohexyl, phenyl or benzyl (meth)acrylate (meth)acrylic esters; vinyl acetate,
Vinyl esters such as vinyl propionate, vinyl butyrate or "vinyl versatate"; vinyl ethers such as methyl-, ethyl-, propyl-, butyl-, amyl- or hexyl vinyl ether; vinyl cyanides such as acrylonitrile; styrene or vinyl Aromatic vinyl compounds such as toluene; olefins such as ethylene; dienes such as butadiene; vinyl halides such as vinyl chloride or vinylidene chloride; or unsaturations such as dialkyl esters of maleic, fumaric, or itaconic acids. There are dibasic acid dialkyl esters, etc.
These can be used alone or in combination of two or more. On the other hand, typical polar monomers copolymerizable with such α,β-ethylenically unsaturated monomers include α,β-ethylenically unsaturated carboxylic acid, vinylsulfonic acid, or styrenesulfonic acid. unsaturated acids or salts thereof; glycidyl compounds such as (methyl)glycidyl (meth)acrylate; (meth)acrylamide or N-methylolated products thereof or alkoxylated products thereof; silanes such as vinyltrichlorosilane or vinyltriethoxysilane. Group-containing α, β-
Ethylenically unsaturated monomers; or various compounds containing reactive polar groups, such as hydroxyl group-containing α,β-ethylenically unsaturated monomers such as β-hydroxyethyl (meth)acrylate. The glass transition temperature (Tg) of the copolymer of the α,β-ethylenically unsaturated monomer listed above and the polar monomer copolymerizable with the unsaturated monomer is 0.
The temperature range is preferably from 10 to 40°C, particularly preferably from 10 to 40°C. If this Tg is less than 0°C, the resulting film will have poor stain resistance, and if it exceeds 50°C, the film-forming ability will be reduced and it cannot be put to practical use. The amount of the polar monomer used is preferably 0 to 14% by weight, particularly preferably 0.5 to 11% by weight of the total monomers. Pigment dispersibility and coating film durability are improved by using this polar monomer, but 14% by weight
If it exceeds 20%, the alkali resistance of the coating film decreases, and efflorescence occurs in the weather resistance of the coating film, which is not preferable. As the radical-generating catalyst used in the emulsion copolymerization, any of the known and commonly used oil-soluble, water-soluble, or redox type catalysts can be used. As such a radical-generating catalyst, any catalyst generally used in emulsion polymerization can be used, but typical examples include water-soluble inorganic peroxides such as hydrogen peroxide and ammonium persulfate, and peroxides. These include sulfates; organic peroxides such as cumene hydroperoxide and benzoyl peroxide; and azo compounds such as azobisisobutyronitrile, and these may be used alone or as a mixture of two or more. The amount used is about 0.1 to 2% based on the total weight of the monomers. Of course, it is also possible to use a method generally known as a redox polymerization method in which these catalysts are used in combination with metal ions and reducing agents. Furthermore, the various monomers described above may be added all at once, in portions, or continuously by dropwise addition, and in the presence of the catalyst described above, 0.
It is polymerized at temperatures of ~100°C, practically 30-90°C. The polymerization temperature during this emulsion copolymerization is preferably in the range of 0 to 90°C. Furthermore, as emulsion dispersion stabilizers used during this emulsion copolymerization, anionic emulsifiers (anionic surfactants), nonionic emulsifiers (nonionic surfactants), cationic surfactants, reactive emulsifiers, acrylic emulsifiers, etc. Substances with surfactant properties such as oligomers or water-soluble polymer substances may be mentioned, and these may also be used in combination of only one type or two types.
Although they can be used in combination, it is usually preferable to use an anionic emulsifier and a nonionic emulsifier in combination. The amount of these emulsifiers used is not particularly limited, but is usually 0.1 to 10% of the total amount of the monomers.
A range of about % by weight is preferred. The emulsion composition thus obtained includes heavy calcium carbonate, light calcium carbonate, cold water powder, powder, kaolin, clay, calcined clay, talc, silica sand, silica lime, bentonite, asbestos, pulp powder, and white carbon. , ultrafine anhydrous silica, dolomite powder, magnesium carbonate,
Precipitated barium sulfate, lithobon, titanium oxide, zinc white, iron oxide, carbon black, chromium oxide,
Fillers or pigments such as ultramarine; phthalate esters such as dibutyl phthalate and dioctyl phthalate; aliphatic dibasic acid esters such as diisodecyl succinate and dioctyl adipate; phosphate esters such as tricresyl phosphate , glycol esters such as diethylene glycol dibenzoate, epoxy plasticizers such as epoxidized soybean oil, various plasticizers such as chlorinated paraffins, polyoxyethylene alkyl phenyl ethers, and polybutene; various anionic and nonionic plasticizers. Surfactants; Dispersants such as salts of condensed phosphoric acid such as pyrophosphoric acid, tripolyphosphoric acid, and hexametaphosphoric acid, polycarboxylic acid salts, naphthalene sulfonate salts; Drying regulators such as mineral spirits and turpentine oil; Ethylene glycol , propylene glycol, glycerin, methanol, and other freeze- or thaw-stabilizing agents; an antifoaming agent or a preservative, etc., to obtain an elastic coating composition, and the composition of the present invention thus obtained has excellent stain resistance. This makes it an elastic paint that forms a film with good low-temperature elongation. Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples, where all parts and percentages are based on weight unless otherwise specified. Reference Example 1 (Preparation example of polyurethane latex) 100 parts of butanediol/adipate polyester diol with a molecular weight of 1200 was dehydrated under reduced pressure at 80°C for 1 hour, and then 265 parts of toluene was added and dissolved. 14.7 parts of hexamethylene diisocyanate was added and reacted with stirring at the same temperature for 3 hours to obtain a polyurethane solution having a solid content (non-volatile content) of about 30%. Next, this polyurethane solution has a molecular weight of 8350.
Mix 190 parts of an aqueous solution containing 8.5 times the amount of polyoxyethylene polyoxypropylene ether with an oxyethylene content of 80%, and disperse it in water.
Toluene was removed by vacuum distillation to obtain a polyurethane latex with a solid content concentration of 40.1%. Reference Example 2 (Preparation example of polyurethane aqueous solution) 3672g of tetramethylene glycol and 2490g of isophthalic acid were reacted at 200℃ for 8 hours, and then
After cooling to 120℃, 1300g of itaconic acid, 3650g
of adipic acid and 2,2'-dimethylolpropionic acid were added, the temperature was raised to 170°C again, and the OH group value was increased by reacting at this temperature for 23 hours.
100, and a polyester with an acid value of 98 was obtained. 560 g of this polyester was dehydrated at 100 DEG C. under reduced pressure, then cooled, 347 g of methyl ethyl ketone was added thereto, and thoroughly stirred and mixed. Next, 250 g of 4,4'-diphenylmethane diisocyanate was added and heated to 70 DEG C.
After reacting at this temperature for 2 hours, 463 g of methyl ethyl ketone was added for dilution. The polyurethane prepolymer solution was gradually added to an aqueous amine solution obtained by previously dissolving 38.7 g of piperazine and 102 g of triethylamine in 3000 g of water to obtain a viscous and transparent reaction product. After removing methyl ethyl ketone from this at 65° C. under reduced pressure, the concentration was adjusted by adding water to obtain a slightly yellow transparent polyurethane aqueous solution with a nonvolatile content of 25.0%, a viscosity of 120 cps, and a pH of 7.0. Reference Example 3 (Example of Preparation of Emulsion Composition) A condenser, a thermometer and a dropping funnel were attached to a stainless steel reaction vessel equipped with a stirrer, and the air in the reaction vessel was replaced with nitrogen gas. A solution with the following composition was prepared. Table 1 Deionized water 200 parts "Emulgen 120" [Nonionic emulsifier manufactured by Kao Atlas Co., Ltd.] 5. Polyurethane latex obtained in Reference Example 1
250〃 Then, while stirring, lower the temperature inside the reaction vessel to 80±2
℃, and a solution having the composition shown in Table 2 below and an aqueous catalyst solution prepared by dissolving 1.5 parts of potassium persulfate in 50 parts of deionized water were added dropwise over 180 minutes to polymerize. During this time, the temperature inside the reaction vessel was maintained at the same temperature. After the dropwise addition was completed, the temperature was kept at the same temperature for 1 hour and stirring was continued. After the stirring was completed, the contents were cooled to 30°C, the pH was adjusted to 7 to 9 with 28% aqueous ammonia, and then filtered. Table 2 Methyl methacrylate (MMA) 214.5 parts n-Butyl acrylate (BA) 175.5〃 Methacrylic acid (MAA) 10.0〃 Deionized water 120〃 “Emulgen 120” 10.5〃 “Neogen R” [Daiichi Kogyo Seiyaku Co., Ltd. ) anionic emulsifier] 16.5 The thus obtained copolymer dispersion had a solid content concentration of 50% and was stable. In addition, each of the above monomers in the copolymer: MMA,
BA and MAA give a Tg of 13°C. Hereinafter, this copolymer dispersion (emulsion composition) will be abbreviated as "E-1". Reference Example 4 (Preparation Example of Emulsion Composition) Except that the use of polyurethane latex in Table 1 was completely omitted, and instead the amount of deionized water used in the same table was changed to 300 parts, A control emulsion composition having a solid content concentration of 50% was obtained in the same manner as in Reference Example 3. Hereinafter, this will be abbreviated as "E'-1". Reference Example 5 (Preparation Example of Emulsion Composition) The emulsion composition obtained in Reference Example 4 “E′-
1", the polyurethane latex of Reference Example 1 was added to
A control emulsion composition was obtained by blending 250 parts. Hereinafter, this will be abbreviated as "E'-2". Reference Example 6 (Preparation Example of Emulsion Composition) The solid content concentration was determined in the same manner as in Reference Example 3, except that the amounts of polyurethane latex and deionized water in Table 1 were changed to 540 parts and 142 parts, respectively. A control emulsion composition having 50% was obtained. Hereinafter, this will be abbreviated as "E'-3". Reference Example 7 (Preparation Example of Emulsion Composition) The solid content concentration was 50% in the same manner as Reference Example 3, except that the composition listed in Table 2 was changed to the composition listed in Table 3 as shown below. An emulsion composition was obtained. Hereinafter, this will be abbreviated as "E-2". Table 3 Methyl methacrylate 130 parts n-Butyl acrylate 140 Styrene 120 Methacrylic acid 10 Deionized water 120 "Emulgen 120" 10 "Neogen R" 16.5 Reference example 8 (Preparation example of emulsion composition) An emulsion composition having a solid content concentration of 50% was obtained in the same manner as in Reference Example 3, except that the composition shown in Table 2 was changed to the composition shown in Table 4 as shown below. Hereinafter, this will be abbreviated as "E-3". Table 4 Methyl methacrylate 200 parts n-Butyl acrylate 190 Methacrylic acid 10 Deionized water 120 "Emulgen 120" 10 "Neogen R" 16.5 Reference example 9 (Preparation example of emulsion composition) Table 2 A control emulsion composition having a solid content concentration of 50% was obtained in the same manner as in Reference Example 3, except that the composition described in Table 5 was changed to the composition described in Table 5 below. Hereinafter, this will be abbreviated as "E'-4". Table 5 Methyl methacrylate 150 parts n-Butyl acrylate 240 Methacrylic acid 10 Deionized water 120 "Emulgen 120" 10 "Neogen R" 16.5 Reference example 10 (Preparation example of emulsion composition) Table 2 A control emulsion composition having a solid content concentration of 50% was obtained in the same manner as in Reference Example 3, except that the composition described in Table 6 was changed to the composition described in Table 6 below. Hereinafter, this will be abbreviated as "E'-5". Table 6 Methyl methacrylate 290 parts n-Butyl acrylate 100 Methacrylic acid 10 Deionized water 120 "Emulgen 120" 10 "Neogen R" 16.5 Reference example 11 (Preparation example of emulsion composition) Table 2 A control emulsion composition was obtained in the same manner as in Reference Example 3, except that the composition described in Table 7 was changed to the composition described in Table 7 below. Hereinafter, this will be abbreviated as "E'-6". Table 7 Methyl methacrylate 164.5 parts n-Butyl acrylate 175.5〃 Methacrylic acid 60〃 Deionized water 120〃 “Emulgen 120” 10 “Neogen R” 16.5〃 Reference example 12 (Preparation example of emulsion composition) Table 1 Instead of the polyurethane latex inside,
A control emulsion composition with a solid content concentration of 50% was obtained in the same manner as in Reference Example 3, except that the same amount of the polyurethane aqueous solution in Reference Example 2 was used, but fine blocks were generated. This emulsion composition was filtered through a 10-mesh wire mesh.
A 10 g block was taken. Examples 1 to 3 and Comparative Examples 1 to 6 The emulsion compositions obtained in Reference Examples 3 to 11 were blended at the blending ratios shown in Table 8 below to produce various elastic coating compositions. They were all made of PVC with a concentration of 21.5%.
It is 50% in PWC.

【table】

[Table] The results of physical property tests for each of these compositions are summarized in Table 9, and the tests for each physical property were conducted in the following manner. Paint film strength and elongation tester: "Tensilon VTM" Tensile speed = 200 mm/min. Test piece: Approximately 0.7
Measurement conditions: 23°C and -10°C Coating film strength and elongation after water resistance test (immersion in water) The above test piece was immersed in water at 23°C for 24 hours. After drying in a dryer at 60℃ for 24 hours,
Measurements were made after leaving the sample under constant temperature and humidity conditions of 23°C and 60% RH for 24 hours. Alkali resistance of paint film The paint was applied to a slate board with a 6 mil applicator, left to dry for 5 days at 23℃ and 60%RH under constant temperature and humidity, and then placed in a 5% NaOH aqueous solution at 23℃ for 1 day. Alternatively, the samples were immersed for 7 days and changes in the coated surface were visually determined. ◎...Excellent○...Good△...Fair After this, the stain resistance of the paint film was visually determined after being subjected to an exposure test for 6 months and 12 months outdoors. ○... Good △... Fair
After treatment for a minute, a nylon pile was spread on the surface, and after being allowed to stand at 50°C for 10 minutes, it was taken out and the state of adhesion of the pile was visually determined. ○...good △...fair Afterwards, the condition of the paint was visually determined. ○...Good△...Normal×...Poor

【table】

Claims (1)

[Claims] 1 Based on the total weight of monomers, the solid content is 2~
In water, in the presence of 30% polyurethane latex and an emulsion dispersion stabilizer, 100 to 86% by weight of an α,β-ethylenically unsaturated monomer having no reactive polar groups and the reactive 0 of an α,β-ethylenically unsaturated monomer containing a reactive polar group that is copolymerizable with an α,β-ethylenically unsaturated monomer containing no polar group.
~14% by weight of a copolymer obtained by emulsion copolymerization at a temperature of 0 to 100°C using a radical-forming catalyst, as an essential component. An elastic coating composition.