JPH0267388A - Sealing material - Google Patents

Abstract

PURPOSE:To obtain a durable and flexible sealing material suitable for use in a cold region by incorporating an inorganic filler into an emulsion of a copolymer of ethylene, an acrylic acid ester whose homopolymer has a Tg of -50 deg.C or lower, and vinyl acetate. CONSTITUTION:A sealing material used in the construction field is obtained by incorporating 51-520pts.wt. inorganic filler into 100pts.wt. (solids) emulsion of a copolymer of 10-30wt.% ethylene, 40-65wt.% acrylic acid ester whose homopolymer has a glass transition point of -50 deg.C or lower (e.g. n-butyl acrylate), and 10-50wt.% vinyl acetate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be used in the construction field for filling gaps such as joints, smoothing uneven parts of buildings, and attaching interior materials such as tiles. related to sealing materials.

[Conventional technology and its issues]

BACKGROUND OF THE INVENTION It has been well known in the construction field to mix synthetic polymer emulsions with inorganic fillers, plasticizers, etc. and use them as sealants, caulking materials, or putty.

Examples of synthetic polymer emulsions include styrene-butadiene copolymer latex (hereinafter referred to as SBR), acrylic comonomer emulsion (hereinafter referred to as acrylic), and ethylene-vinyl acetate copolymer emulsion (hereinafter referred to as EVA). However, the following problems are known.

(178BR: Poor weather resistance, and the construction diameter deteriorates significantly over a long period of time.

(2) Acrylic: It has poor alkali resistance, and in an alkaline atmosphere, the construction diameter gradually becomes brittle over a long period of time, resulting in loss of flexibility.

(31EVA: Excellent weather resistance and stability, but poor flexibility.

Especially when used in cold regions such as Hokkaido and Tohoku,
Current water-based sealants have insufficient performance in terms of flexibility or durability, and it is desired to develop a new sealant that is superior in flexibility and durability. Up to now, it has been proposed to use a terpolymer emulsion of ethylene-vinyl acetate-acrylic ester in the production of water-based sealants (Japanese Patent Application Laid-open No. 159271/1983). Because the content of acrylic ester is small and the glass transition temperature of the homopolymer is high, sufficient ball resistance (flexibility) cannot be obtained.

[Elaborate means to solve problems]

In the present invention, the copolymer composition is 10 to 30 i% of ethylene.
, the glass transition temperature (Tg) of the homopolymer is -50℃
This is an aqueous sealing material made by mixing an inorganic filler with a comonomer emulsion consisting of 40 to 65 acrylic esters and 15 to 50% by weight of vinyl acetate as shown below.

An object of the present invention is to provide a sealing material for cold regions that has both the durability of EVA and the flexibility of acrylic.

As will be explained in more detail below, all ratios and 'rg are values for solid content.

The ethylene content in the copolymer and emulsion that is the main component of the present invention is 10 to 30! i%.

If the ethylene content is less than 10% by weight, the alkali resistance will be insufficient, while if it exceeds 30% by weight, the emulsion state will become unstable, which will impede practical use.

The content of acrylic ester is 40-65% by weight. If the content of acrylic acid ester is less than 40% by weight, it will be difficult to reduce the Tg of the copolymer emulsion to -30°C or less, while if it exceeds 65% by weight, the vinyl acetate content in the copolymer emulsion will be low. This results in loss of durability.

If the Tg of the monomer emulsion is higher than 130° C., sufficient flexibility of the sealant cannot be obtained.

The acrylic ester used in the present invention has a homopolymer Tg of 1509C or less, normal propyl acrylate (hereinafter referred to as n-PA), normal butyl acrylate (hereinafter referred to as n-BA), hexyl Common examples include acrylate (hereinafter referred to as HA), 2-methoxyethyl acrylate (hereinafter referred to as C-1), and 2-ethylhexyl acrylate (hereinafter referred to as 2M).

There are no particular restrictions on the method for producing the copolymer emulsion, which is the main component of the present invention, and any known emulsification method can be used. There are no particular restrictions on the polymerization conditions, but in general, polymerization The temperature is 20-8ff'α for a catalyst.
Examples include persulfates such as potassium persulfate, hydrogen peroxide, and various organic peroxides.

In the case of a redox initiation system, a reducing substance such as formaldehyde sodium sulfoxylate is further used in combination.

Emulsifiers include polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, and other stomach-retaining colloids;
Examples include nonionic surfactants such as polyoxyethylene condensates and polyoxyethylene polyoxypropylene block copolymer, and anionic surfactants such as alkylbenzene sulfonates and lauryl sulfate salts. They can be used or used in combination, and the amount used is usually 2 to 10% by weight of the total monomer amount.

The copolymer emulsion, which is the main component of the present invention, may further contain additives such as known buffers, antifoaming agents, and preservatives, if necessary.

In the present invention, styrene-inbutylene aqueous dispersion 1i, S
BR latex, acrylic emulsion, ethylene-vinyl acetate terpolymer emulsion, natural rubber latex, acrylonitrile-butadiene copolymer latex (NBR), methyl methacrylate-butadiene copolymer latex (MBR).

One type of polychloroprene latex (CFI), vinylpyridine copolymer emulsion (■P), polyisoprene latex (IR), vinyl chloride copolymer emulsion (PVC), and vinylidene chloride copolymer emulsion (PVdc) It is also possible to use the above together. When used in combination, the resin content of the other resin emulsion is 50% of the copolymer emulsion that is the main component of the present invention.
It can be blended under heavy weight, especially below 25 weight. If a large amount of other resin emulsions are used, there is a risk that the excellent durability and flexibility of the comonomer emulsion, which is the main component of the present invention, may be impaired.

The above-mentioned ethylene-vinyl acetate terpolymer emulsion is an emulsion obtained by copolymerizing, for example, the following monomers in addition to ethylene and vinyl acetate. Vinyl cyanide monomer, methacrylic acid ester monomer, unsaturated carboxylic acid monomer, vinyl ether monomer, amide monomer, maleimide monomer, halodanated olefin monomer.

Sealing materials are used to seal various gaps in construction work, etc., to maintain airtightness or waterproofing, but after construction, sealants often come into direct contact with the outside air, and are especially flexible in cold regions. , durability is important.

The present inventors have discovered that a copolymer emulsion of ethylene-acrylic acid ester-vinyl acetate 9 having a Tg of -30°C or lower is excellent as a paste emulsion for sealing materials for cold regions.

The solid content of the comonocratic emulsion of the present invention is not particularly limited, but is preferably 50% by weight or more. Solid content is 50m! %
If a copolymer emulsion with a low density is used, the volumetric shrinkage after curing (so-called eye thinning) will be large, which is not practical.

A sealing material is produced by adding an inorganic filler, a plasticizer, a dispersant, a wetting agent, a thickener, an antifoaming agent, a fungicidal agent, and a pigment to the copolymer emulsion of the present invention as necessary. , its in-shell formulation is as follows.

Inorganic fillers include calcium carbonate, silica sand, and clay.
Talc, silica, titanium oxide, iron oxide, zinc oxide, lead oxide, alumina, perlite, asbestos, rock wool, mica, magnesium hydroxide, aluminum hydroxide,
Examples include diatomaceous earth, white dragonite, anhydrite, micalite, carbon black, barium sulfate, and sulfur, and these may be used alone or in combination of two or more.

The amount of inorganic filler used is copolymer emulsion solid content 1
00 parts by weight is generally 51 to 520 parts by weight. 5
If the amount is less than 1 part by weight, the film of the sealant may not have sufficient strength, and the eyesight will be increased. On the other hand, if it exceeds 520 parts by weight, the film tends to become hard and its elasticity decreases.

Examples of plasticizers include phthalate ester plasticizers, polyester plasticizers, phosphate ester plasticizers, aromatic polybasic acid ester plasticizers, aliphatic dibasic acid ester plasticizers, epoxy plasticizers, and pentamyl ester plasticizers. Erythrite esters and the like are used. The blending amount of the plasticizer is 0 to 12 parts by weight per 100 parts by weight of the solid content of the copolymer emulsion. If the amount added exceeds 12 parts by weight, a decrease in adhesive force may be observed due to pleating of the plasticizer.

Examples of dispersants include condensed phosphates such as tripolyphosphate and hexametaphosphate, water-soluble polyacrylates,
Anionic or nonionic interfacial 1"& sexing agents, styrene-maleic anhydride 1-7 ester salts, etc. can be added. The amount added is usually 3 m
It is generally less than k%.

Nonionic surfactants, such as nonylphenol polyoxyethers, are often used as wetting agents. The amount added is 3. of the inorganic filler. i: preferably 1% or less,
If it exceeds 3% by weight, the water resistance of the sealant tends to decrease.

Ethylcellulose, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, alginic acid, carrageenan, natural water-soluble polymers such as gum arabic, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, and polyester are used as thickeners to adjust the viscosity of sealants. Synthetic water-soluble polymers such as ethylene oxide and polyvinylpyrrolidone can be used. The amount added is preferably 31 or less of the amount of the copolymer emulsion.

As pigments, titanium oxide, chromium oxide, zinc oxide, iron oxide, cadmium sulfide, carbon dioxide (RFe"CFeu (
It is possible to use inorganic pigments such as CN), ), Ft=NH+K r NH4), and organic pigments such as cyanin del-azo pigments. The amount added is preferably 5 parts by weight or less based on the amount of the copolymer emulsion.

Any antifoaming agent and antifungal agent may be used as long as they can be used in the copolymer emulsion, and the amount used is usually 5000 ppm or less based on the blended composition.

A sealing material is obtained by mixing a copolymer emulsion, an inorganic filler, and if necessary a plasticizer, a dispersant, a wetting agent, a thickener, an antifoaming agent, a fungicide, and a pigment, and its manufacturing method is extremely simple. It is. It is sufficient to simply mix the above-mentioned raw materials, and all the ingredients may be charged in a blender at once and heated, or a portion of the ingredients may be added first, and then the remaining portions may be sequentially added and mixed. In the latter case, the order of adding the raw materials is completely arbitrary, but it is preferable to add the inorganic filler first from the viewpoint of workability.

As the mixing machine, any type of mixer can be used as long as it has sufficiently high mixing efficiency.

By the above operations, a high viscosity putty-like sealant can be obtained.

〔Example〕

Reference Example (Manufacturing Example of Ethylene-Vinyl Acetate-Acrylic Acid Ester Co-Unit - Test 41) The following raw materials were charged into a stainless steel autoclave equipped with an electromagnetic stirrer and having an internal volume of 10 tons.

Pure water 300B Vinyl acetate 15005' n-BA 1500. ! il emal rn 9
31 130g (manufactured by Kao) Poval B-0540
9 (Denki Kagaku Kogyo) Hydroxyethylcellulose
15. ! ii+ (Fuji Chemical Industry ff) Sodium acetate
6g Raise the internal temperature to 70°C and add ethylene to 60'rJ/cm
0.6 g of ammonium persulfate was added to start polymerization. The internal temperature was kept constant by adjusting the jacket temperature. After 10 hours, it was cooled and the contents were taken out. The content is a stable emulsion with few coarse particles, solid content 55.2% by weight, viscosity 300 cps (
BM type rotary viscometer, 30°C, 3 Or-p-m-), the polymer composition of which is ethylene 14 weight it%, n-BA4
5 N plate, vinyl acetate 41% by weight, Tg - 31°C.

Example 1 Sealing materials shown in Table 2 were prepared using the copolymer emulsions shown in Table 1. The preparation method was to stir the inorganic filler and copolymer emulsion with a laboratory hand mixer, then add the remaining additives and stir in the same manner (%, parts are based on weight). .

In addition, the copolymer emulsions made by I in Tests 42 to 10 are as follows:
The procedure was exactly the same as in Reference Example except that the charging ratio of monomers (vinyl acetate, acrylic ester, ethylene) and the type of acrylic ester were changed.

(1) Copolymer Emulsion Table-1 The EVA, acrylic, and SBR used in Tests/1611-13 are as follows.

gVA: Denka EVA Tex ÷ 56 manufactured by Denki Kagaku Kogyo Co., Ltd. (solid content 55%) Acrylic: Used raE921 J manufactured by Japan Synthetic Rubber Co., Ltd. (solid content 60%) SER: r Njpol Lx 119 manufactured by Nippon Zeon Co., Ltd.
J used (solid content 50%) (2) Inorganic filler calcium carbonate "NS 100" manufactured by Nikitto Funka Kogyo Co., Ltd. Used: "NN Chikara Orin Clay" manufactured by Ueya Kaolin Kogyo Co., Ltd. Used: "Micro Ace" manufactured by Nippon Talc 1" Clay talc dispersant used: Sodium tripolyphosphate: Reagent (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.) used.

The measurement was performed using the following method.

(1) Tensile strength/elongation 15 (] + m
Cured it according to the curing conditions for the moisture-curing one-component type of A3758, and punched it out with a No. 3 dumbbell to make a test piece. This test piece was used as an autograph (Shimadzu Corporation A
G-2000A type), tensile speed 50 mm/min, temperature (20,0, -10°-20°C), humidity 45-65%.
Measurements were made under various conditions on the day.

(2) Weather resistance A constant test piece prepared in the same manner as in (1) was tested using the Sunshine Unizu Meter (Ska Test Machine Company Guide-8UN-H).
C) for 1000 hours, and the elongation was measured at 20°C in the same manner as in (1).

(3) Alkali resistance A test piece prepared in the same manner as in (1) was immersed in a 5% aqueous solution of sodium hydroxide for 168 hours.
The elongation was measured at 20°C in the same manner as above.

Table 2: The results of Tests 161 to 7, which are examples of the present invention, were satisfactory in both cold resistance and durability. On the other hand, when the Tg of the copolymer emulsion is higher than 30°C, the wear resistance is inferior (Experiments 48 and 9);
If the ethylene content or vinyl acetate content in the copolymer is low, the alkali resistance will be poor (Experiments 49 and 10).
) Regarding commercially available polymer emulsions, results were obtained that EVA is inferior in terms of cold resistance, acrylic in terms of alkali resistance, and SBR in terms of weather resistance and alkali resistance. .

〔Effect of the invention〕

INDUSTRIAL APPLICABILITY The present invention is a sealing material with excellent cold resistance and durability suitable for the construction field.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] 10-30% by weight of ethylene, 40-6 acrylic ester with a homopolymer glass transition temperature of -50°C or lower
An aqueous sealing material prepared by mixing a copolymer emulsion containing 5% by weight of vinyl acetate and 15-50% by weight of vinyl acetate with an inorganic filler.