JPH0621266B2 - Undercoat paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Purpose of the invention "Industrial field of application" The present invention is a coating film waterproofing method for coating the surface of a building or structure, particularly for waterproofing the building. The present invention relates to the undercoat paint used in, and particularly to the undercoat paint that is particularly useful in a waterproof coating method requiring a high degree of durability under conditions where there is a large difference in cold and heat conditions or conditions where alkali resistance is required. , Which can be widely used in the civil engineering and construction industry.

"Prior art" Undercoating paints, or primers, have been widely used to improve the adhesion between the coating and the substrate in the coating prevention method using synthetic rubber emulsion, acrylic emulsion or urethane rubber. . Chlorinated polypropylene is mainly used as a constituent of such undercoat paint, and vinyl chloride-vinyl acetate copolymer, chlorinated rubber and the like are also used.

[Problems to be Solved by the Invention] However, the above-mentioned undercoat paint has a very small film strength formed thereby and easily undergoes brittle fracture at low temperature, so that adhesion to a rubber-based paint film with large expansion and contraction It has a problem of thermal decomposition under bad or climatic conditions with a large difference in cold heat. Even if it does not have such a problem, it has a problem that the alkali resistance is remarkably poor especially under the condition of being heated to about 80 ° C., and the adhesion property is deteriorated with time on a highly alkaline concrete wall surface. It is a thing.

The inventors of the present invention have conducted various studies to find an undercoat paint which does not have the above-mentioned problems, and completed the present invention.

(B) Structure of the Invention "Means for Solving Problems" The present inventors have completed the present invention by finding that the above problems can be solved by using two kinds of compounds in combination.

That is, the present invention comprises a copolymer of vinyl chloride 50 to 90% by weight and vinylidene chloride 50 to 10% by weight and chlorinated paraffin, and the ratio of both is 50 to 95%.
The present invention relates to an undercoat paint for civil engineering, which is characterized by containing 50 to 5% by weight of chlorinated paraffin.

Copolymer of vinyl chloride and vinylidene chloride A copolymer of vinyl chloride and vinylidene chloride can be prepared by a conventional polymerization method of vinyl chloride and vinylidene chloride, that is, a suspension polymerization method, an emulsion polymerization method or a solution polymerization method. It is obtained by radical copolymerization.

An example of the copolymerization in the case of the preferred suspension polymerization method according to the present invention will be described. As a suspending agent, partially saponified PV
A, methyl cellulose, a copolymer of ethylene oxide and propylene oxide, a copolymer of vinyl acetate and maleic acid, or the like is used, and benzoyl peroxide, lauroyl peroxide, di2-ethylhexyl peroxydicarbonate as a radical-generating catalyst. ,
It can be obtained by polymerization using α, α′-dimethylpareronitrile or the like in water as a medium at a polymerization temperature of 40 to 70 ° C. with stirring for 7 to 20 hours. In the copolymer of vinyl chloride and vinylidene chloride, the ratio of both is 50 to 90% by weight of vinyl chloride and 50 to 10% by weight of vinylidene chloride.
Which achieves the object of the invention.

As the copolymer, a copolymer obtained by copolymerizing vinyl chloride and a radical-polymerizable monomer other than vinylidene chloride as a third component is also applicable to the present invention.

At that time, the amount of the monomer of the third component is preferably 20% by weight or less based on the total amount of monomers so as not to impair the achievement of the object of the present invention.

Examples of the third component monomer include vinyl acetate, butyl vinyl ether, hydroxyethyl acrylate, maleic anhydride, glycidyl methacrylate and the like.

The copolymer of vinyl chloride and vinylidene chloride preferred for the present invention is a toluene-soluble copolymer. Since a copolymer soluble in toluene has a remarkably good compatibility with a chlorine-compatible paraffin, an undercoat paint using the copolymer can give a film having good adhesion to a base and high flexibility.

In order to make the copolymer soluble in toluene, vinylidene chloride, which is an easily polymerizable monomer, is dividedly added to the polymerization reactor, that is, one part or all of vinylidene chloride is sequentially added after the initiation of the polymerization reaction. It is necessary to adopt a polymerization method, a polymerization method in which a chain transfer agent is used in combination, or a polymerization method in which both of them are used in combination, and a copolymer soluble in toluene can be obtained by such a polymerization method.

As the chain transfer agent, it is preferable to use a chain transfer type monomer containing a methyl group or a chloromethyl group, particularly methallyl chloride or γ, γ'-dichloroisobutylene.

Particularly preferred copolymers of the present invention using methallyl chloride or γ, γ'-dichloroisobutylene are vinyl chloride 80 to 55% by weight, vinylidene chloride 19 to 40% by weight, and methallyl chloride as a constituent ratio of each monomer. Alternatively, it is obtained by copolymerizing 1 to 5% by weight of γ, γ'-dichloroisobutylene.

Although the solubility of the copolymer in toluene can be sufficiently judged by visual observation, for example, 20 parts by weight of the copolymer is mixed with 80 parts of toluene.
The mixture was added to 1 part by weight, stirred for 1 hour, and allowed to stand for 1 day to pass through the insoluble matter. After drying, the insoluble matter was 5% of the first copolymer.
It is preferably 0% by weight or less, more preferably 2
It is preferably 0% by weight or less, particularly preferably 0.5% by weight or less for the present invention.

Chlorinated Paraffin Examples of the chlorinated paraffin used in the present invention include commercially available products that are commonly available, among which those having a chlorine content of 30 to 70% by weight are preferable, and more preferably 40 to 60% by weight. The molecular weight is preferably 400 to 600. If the amount is out of the above range, there is a possibility that the adhesiveness to concrete or a slate wall or the like will be poor, or the flexibility will be deteriorated to exhibit low temperature brittle fracture.

Ratio of combined use The ratio of combined use of the copolymer of vinyl chloride and vinylidene chloride and the chlorinated paraffin is 50 to 95% by weight of the total amount of both and 50% of the chlorinated paraffin.
It is necessary to be 5 to 5% by weight, preferably 60 to 80% by weight of the copolymer and 40 to 20% by weight of chlorinated paraffin. When the amount of the copolymer is less than 50% by weight, the heat resistance and the adhesion to the base become poor, and when it exceeds 95% by weight, the flexibility of the film is lowered and there is a risk of brittle fracture at low temperature. Also, the adhesiveness with the base is reduced.

Undercoat paint A copolymer of vinyl chloride and vinylidene chloride and chlorinated paraffin can be applied as an undercoat paint by forming an emulsion dispersed in water or a solution dissolved in an organic solvent.

As the undercoat paint, a solution is preferable in the present invention from the viewpoint of production and handling, and as the solvent for forming the solution, those generally used in paints can be used,
Toluene or a mixed solvent containing 30% by weight or more of toluene is preferable.

Specific examples of the solvent used include aromatic compounds such as benzene, xylene, solvent naphtha, monochlorobenzene, nitrobenzene, and tetralin, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethylene, perchlorethylene, methylchloroform, and the like. Examples thereof include chlorinated hydrocarbons, esters such as ethyl acetate, butyl acetate and cellosolve acetate, and ketones such as methyl ethyl ketone and methyl isobutyl ketone.

The amount of vinyl chloride and vinylidene chloride copolymer and chlorinated paraffin in the undercoating material is determined based on the fluidity required for the undercoating material.For example, the one applied to the coating method using a spray gun is the undercoating material. It is preferable that the coating composition contains 10 to 20% by weight.

"Working" The present invention is characterized in that, as a component of an undercoat paint, a specific amount of both a copolymer of vinyl chloride and vinylidene chloride in a specific copolymerization ratio and a chlorinated paraffin are used in combination. Adhesion to the base, which was not observed with conventional undercoating, is excellent, and adhesion to a coating film that has elasticity such as rubber is also good. Basic durability such as cold resistance, heat resistance and alkali resistance It was made by finding an excellent action of satisfying all of the performance and the like. INDUSTRIAL APPLICABILITY The present invention can provide a base coating material which is far superior to the conventional one.

[Examples] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Each property of the undercoat paint of each example was evaluated by the following method with respect to a test piece obtained by applying a ²⁰ gr / m ² undercoat paint as a solid content to a slab concrete piece.

1) Warm-cooling repeated test A repeated test was carried out at -40 ° C for 5 HR and then at 80 ° C for 5 HR for 2000 HR, and the appearance was visually observed.

2) Degradability due to dehydrochlorination 1) Before and after the test of 1), a film of the undercoat paint was taken and the decrease in chlorine content was determined with the chlorine content before the test being 100.

3) Adhesive force The adhesive force before and after the test of 1) was measured by a vertical suction type test.

Example 1 (1) Method for producing copolymer 5 Vinyl chloride 990 gr, vinylidene chloride 255 gr in an autoclave, OKS-7514 as a suspending agent (partially saponified PVA with a saponification degree of 40 mol%, Nippon Synthetic Chemical Co., Ltd.)
7.5 gr and Epan 485 (block copolymer of ethylene oxide and propylene oxide, Daiichi Kogyo Seiyaku Co., Ltd.)
15 gr, and used as a radical-generating catalyst
Ethylhexyl peroxydicarbonate (5 gr) and pure water (3,000 gr) were charged, and the mixture was stirred at 500 rpm to give 6
A polymerization reaction was performed at 0 ° C. Vinylidene chloride 5 every 2 HR on the way
1 gr was added under pressure 5 times (total amount 255 gr), and a polymerization reaction was carried out for 12 hours. After centrifugal separation and dehydration, it was dried to obtain a powdery copolymer.

(2) Preparation of undercoat paint 80 g of the copolymer obtained in (1) above, 20 g of Empara 40 (chlorine content 41%, chlorinated paraffin having a molecular weight of 560, manufactured by Ajinomoto Co., Inc.), and 400 g of toluene were mixed to homogeneity. To obtain an undercoat paint.

The results of evaluating the physical properties of this undercoat paint are shown in Table 1.

Examples 2 to 8 and Comparative Example 1 The composition of the charged monomers was changed according to Table 1 in the same manner as in the production method of the copolymer (1) of Example 1 (the vinylidene chloride monomer was charged in the same manner as in Example 1). The results are shown in Table 1 in which the physical properties of the undercoating paint obtained by obtaining copolymers and the types and amounts of chlorinated paraffins used are shown in Table 1.

Comparative Example 2 A polymer was produced in the same manner as in the production method of the copolymer (1) of Example 1, except that only 1245 gr of vinyl chloride was used.
Table 2 shows the results of the evaluation of the physical properties of the undercoating paint obtained as shown in Table 2 along with the type and amount of chlorinated paraffin used.
Shown in.

Comparative Example 3 1245 g of vinylidene chloride alone instead of vinyl chloride
Table 2 shows the results of evaluating the physical properties of the undercoat paint obtained in the same manner as in Comparative Example 2 except that r was used.

Comparative Example 4 Undercoat paint obtained in the same manner as in Comparative Example 2 except that the vinyl chloride homopolymers obtained in Comparative Examples 2 and 3 and the vinylidene chloride homopolymer were mixed in a weight ratio of 66:34. Table 2 shows the results of the evaluation of the physical properties.

(C) Effect of the invention The undercoat paint of the present invention has good adhesion to the base and coating film, and is excellent in performance such as cold resistance, heat resistance, and alkali resistance. It has a great effect in terms of utilization, and since it is an undercoat paint suitable for a waterproof coating method that uses a highly elastic coating film such as a rubber emulsion, the waterproof effect of the waterproof coating is significantly improved. It has the excellent effect of

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Claims (1)

[Claims] 1. A copolymer of 50 to 90% by weight of vinyl chloride and 50 to 10% by weight of vinylidene chloride and a chlorinated paraffin, wherein the proportion of both is 50 to 95% by weight of the copolymer and chlorinated paraffin. An undercoat paint for civil engineering, which is characterized by being 50 to 5% by weight.