JPH11209523A - Chloroprene latex composition and adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chloroprene latex and an adhesive composition having excellent heat resistance and weather resistance. SOLUTION: The chloroprene latex composition and an adhesive composition comprise (A) a chloroprene latex and (B) finely granular zinc flower having <200 nm average particle diameter. The blended amounts are preferably 0.05-30 pts.wt. of the component B based on 100 pts.wt. of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a process for producing a powder having an average particle diameter of 200 n.
The present invention relates to a chloroprene latex composition and an adhesive composition thereof, which contain fine particles of zinc oxide having a particle diameter of less than 0.5 m, and a chloroprene latex composition and an adhesive composition having excellent heat resistance and weather resistance.

[0002]

2. Description of the Related Art It has been known that zinc oxide is blended with carboxyl-modified chloroprene latex in order to improve the heat resistance of a chloroprene latex composition and its adhesive composition. However, the average particle size of zinc white, which is generally known, is 200 to 500 nm, and the effect of improving heat resistance is insufficient, and the large particle size has a problem in dispersion stability.

On the other hand, as a method for improving weather resistance,
Benzotriazole-based, benzophenone-based, triazine-based, hindered amine-based, organic nickel-based organic light stabilizers and other methods are known, but these organic light stabilizers are insoluble in water, Chloroprene latex had the disadvantage of being difficult to mix. Furthermore, the effect of these organic light stabilizers has the disadvantage that they are not permanent.

Therefore, hitherto, if it is desired to simultaneously improve the heat resistance and weather resistance of a chloroprene latex composition or its adhesive composition, both water-insoluble zinc white and an organic light stabilizer must be used. It was blended as a dispersion of zinc white and an organic light stabilizer using various emulsifiers, or was blended / added directly to latex.

[0005] However, in the case of the former method, when a large amount of zinc white and an organic ultraviolet absorber are added, the amount of the emulsifier contained in the latex is increased, and the adhesive properties are deteriorated. Had occurred.
For this reason, in order to maintain the balance of the adhesive properties and the like, there is a limit in the amount of zinc white and the organic light stabilizer, and thus there is also a limit in improving the heat resistance and weather resistance. In addition, the latter method has a disadvantage that the zinc white particles are easily aggregated and difficult to uniformly disperse, and thus the heat resistance and the weather resistance cannot be satisfactorily improved.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional chloroprene latex composition and the adhesive composition thereof, and provides a chloroprene latex composition and an adhesive excellent in heat resistance and weather resistance. It is intended to provide a composition.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by blending fine particles of zinc oxide having an average particle diameter of less than 200 nm with chloroprene latex, the heat resistance is improved. The present inventors have found that a chloroprene latex composition and an adhesive composition having excellent weather resistance can be obtained, and have completed the present invention. That is, the present invention provides a chloroprene latex composition and an adhesive composition which are excellent in heat resistance and weather resistance by containing zinc fine particles having an average particle diameter of less than 200 nm.

Hereinafter, the contents of the present invention will be described in detail. The chloroprene polymer contained in the chloroprene latex composition of the present invention is at least one of a homopolymer of 2-chloro-1,3-butadiene (hereinafter, referred to as chloroprene) and a monomer copolymerizable with chloroprene and chloroprene. Is a copolymer obtained by copolymerizing

The monomer copolymerizable with chloroprene in the present invention includes, for example, 2,3-dichloro-1,3-
Butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and the like, and if necessary, two or more kinds may be used. .

In particular, a carboxyl-modified chloroprene latex composition obtained by copolymerizing one or more kinds of monomers containing a carboxyl group has further improved heat resistance. Examples of the monomer containing a carboxyl group include acrylic acid, methacrylic acid, 2-ethylacrylic acid,
There are propylacrylic acid, 2-butylacrylic acid, and itaconic acid, and particularly, a carboxy-modified latex composition using methacrylic acid has extremely excellent heat resistance.

The emulsifier and / or dispersant used in the chloroprene latex composition of the present invention is not particularly limited, and various anionic, nonionic, and cationic types commonly used in chloroprene latex can be used. Examples of the anionic emulsifier include a carboxylic acid type and a sulfate type. Examples thereof include alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, sodium naphthalene sulfonate and formaldehyde. And condensates. Specific examples of the nonionic type include polyvinyl alcohol or a copolymer thereof (for example, a copolymer with acrylamide), polyvinyl ether or a copolymer thereof (for example, a copolymer with maleic acid), polyvinyl pyrrolidone or a copolymer thereof. Examples thereof include polymers (for example, copolymers with vinyl acetate), those obtained by chemically modifying these (co) polymers, and cellulose derivatives (hydroxyethyl cellulose). Specific examples of the cationic type include an aliphatic amine salt, an aliphatic quaternary amine salt, an aromatic quaternary ammonium salt, a heterocyclic quaternary ammonium salt, and the like. For example, octadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, Dodecyltrimethylammonium chloride, dilauryldimethylammonium chloride and the like.

The amount of the emulsifier and / or dispersant used in the chloroprene latex composition of the present invention is preferably from 1 part by weight to less than 20 parts by weight based on 100 parts by weight of the initially charged chloroprene monomer. If the amount is less than 1 part by weight, the emulsifying power is insufficient, and if it is more than 20 parts by weight, the adhesive strength is reduced when used as an adhesive composition.

The chloroprene latex composition of the present invention can be obtained by adding the above-mentioned fine zinc powder to a chloroprene latex containing the above-mentioned chloroprene polymer obtained by emulsion polymerization according to a method exemplified below. . The method for polymerizing the chloroprene polymer in the present invention is not particularly limited, and a polymerization temperature, a polymerization catalyst, a chain transfer agent, a polymerization terminator, a final polymerization rate, demonomerization, concentration conditions, and the like are appropriately selected and controlled. Thus, the solid content concentration, the molecular weight of the toluene-soluble portion, the gel content, and the like can be adjusted.

The polymerization temperature of the chloroprene polymer in the present invention is not particularly limited. The polymerization catalyst is a persulfate such as potassium persulfate, an organic peroxide such as tert-butyl hydroperoxide, or the like, and is not particularly limited.

The type of the chain transfer agent is not particularly limited, and those usually used for emulsion polymerization of chloroprene can be used, but a xanthate type or a mercaptan type is preferred. The chain transfer agent can be added not only during the preparation but also during the polymerization.

The polymerization terminator (polymerization inhibitor) is not particularly limited. For example, 2,6-tert-butyl-
4-methylphenol, phenothiazine, hydroxyamine and the like can be used.

The final polymerization rate is not particularly limited and can be arbitrarily adjusted. Unreacted monomers are removed by a demonomerization operation, but the method is not particularly limited. The obtained chloroprene latex can be adjusted to a required concentration by concentrating or diluting by adding water or the like. Examples of the method for concentration include concentration under reduced pressure, but are not particularly limited.

In the present invention, it is essential that the fine particles of zinc white have an average particle size of less than 200 nm as measured by the BET method. Zinc white is generally used as a cross-linking agent (or vulcanizing agent) for chloroprene rubber. By using the fine zinc fine particles having an average particle diameter of less than 200 nm according to the present invention, more excellent heat resistance and weather resistance can be obtained. Is obtained. Further, by using fine particles of zinc oxide having an average particle diameter of preferably 150 nm or less and 1 nm or more, more preferably 100 nm or less and 1 nm or more, further excellent heat resistance and weather resistance can be obtained.

The amount of the zinc fine particles used in the present invention depends on the required performance, but is preferably 0.05 to 30 parts by weight, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the chloroprene polymer in the chloroprene latex. It is 1 to 10 parts by weight. 3
If it is added in excess of 0 parts by weight, weatherability is excellent, but sedimentation and the like occur due to a decrease in dispersion stability, which is not preferable. If the amount is less than 0.05 parts by weight, sufficient weather resistance cannot be obtained. In the present invention, the average particle diameter is 20.
Fine particle zinc oxide having a particle diameter of less than 0 nm is more likely to cause aggregation of particles than a conventionally used zinc particle having a large particle diameter, and thus is added after being uniformly dispersed in water using an emulsifier and / or a dispersant. Is more preferable. The addition time of the zinc fine particles of the present invention is preferably after completion of the polymerization operation or after adjustment of the solid content concentration, but is not limited thereto.

The adhesive composition can be obtained by mixing the chloroprene retex composition of the present invention with various additives such as tackifiers usually used in adhesive compositions. In the present invention, the chloroprene latex composition and the adhesive composition containing fine particles of zinc oxide having an average particle diameter of less than 200 nm may be added to benzotriazole, benzophenone, triazine, hindered amine, organic nickel, and phenol-based organic compounds. When a light stabilizer is added, more excellent weather resistance can be obtained.

The chloroprene latex composition and the adhesive composition according to the present invention must contain chloroprene latex and zinc oxide fine particles having an average particle diameter of less than 200 nm. , Tackifier, anti-aging agent, filler, pH
Conditioning agents, thickeners, vulcanizing agents, curing agents, antibacterial agents, fungicides, and the like can be used within the scope of the present invention.

[0022]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. here,
The weather resistance and the heat creep property test of the adhesive were evaluated by the following methods. Other measurement methods are shown below. In the following description, the amount of addition and the like are based on weight unless otherwise specified.

[Weather Resistance Test] 200 g / m ² of a chloroprene latex composition or an adhesive composition was applied to blotting paper Shim-1 (trade name, manufactured by KOKUYO Co., Ltd.) with a brush, and the temperature was 55
At 5 ° C. for 5 minutes, using a long life xenon weather meter (trade name, manufactured by Suga Test Instruments Co., Ltd.) for 1 hour, 3 hours
The change in color tone after irradiation for 5, 5 and 7 hours was examined. Irradiation intensity is 390W / m ² , temperature is 63 ° C, humidity is 50% R
Set to H and no rain shower is used. The color tone was measured by a yellowness index using a # 80 color measuring system (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).

[Heat resistance creep property test] Canvas (25 × 5
0 mm) The adhesive composition was brushed on each of two sheets at 200 g /
m ^{2 was} applied and dried in an atmosphere at 80 ° C. for 5 minutes, and then the applied surfaces were bonded and pressed with a hand roller. After pressing for 24 hours, left in an atmosphere of 80 ° C. for 20 minutes, apply a load of 1 kg under the atmosphere of 80 ° C. in the manner of performing a 180 ° peeling test, and leave for 30 minutes. m
m) was measured.

[Solid Content Concentration]
And An aluminum dish containing 2 ml of the latex sample was precisely weighed and designated as B. Place the aluminum dish containing the latex sample in 110
After drying in an atmosphere at a temperature of 2 ° C. for 2 hours, the sample was precisely weighed and designated as C. The solid concentration (%) was determined by the following equation. Solid concentration = {(CA) / (BA)} × 100

[Weight average molecular weight Mw of soluble part] GPC measurement was performed under the following conditions. The molecular weight was calculated in terms of polystyrene. For the sample, the separated sol was adjusted to a 0.1% by weight THF solution. Column size: 7.5mmφ × 50mm (GUAR
D), 7.5 mmφ × 300 mm (Mixed-B) Column temperature: 35 ° C., solvent: THF, Outflow rate: 1 ml / min Detector: SIMAZU RID-6A

[Measurement of Gel Content] A latex sample was freeze-dried and precisely weighed to obtain A. After dissolving with toluene (adjusted to 0.6%) at 23 ° C. for 20 hours, the gel was separated using a centrifuge and further using a 200-mesh wire net. The gel component was air-dried and then dried for 1 hour in a 110 ° C. atmosphere. The gel content was calculated according to the formula. Gel content = B / A × 100%

Examples 1 and 2 and Comparative Example 1 The chloroprene latex composition was polymerized at a formulation and a polymerization temperature shown in Table 1 under a nitrogen atmosphere while adding a 2% aqueous solution of potassium persulfate as a catalyst. Thiodiphenylamine was added to 0.02 parts by weight based on 100 parts by weight of the initial chloroprene monomer to terminate the reaction. After the polymerization, the monomers were removed under reduced pressure, and the solid content was adjusted to 50% under reduced pressure while heating.

The obtained latex was blended according to the formulation shown in Table 1 to obtain latex compositions of Examples 1 and 2 and Comparative Example 1. The unit of the compounding amount is part by weight of the solid content. Zinc white has an average particle size of about 10 n as described in Table 1.
ZW-101 (trade name, manufactured by Sumitomo Osaka Cement Co., Ltd.), ZW-143 (trade name, manufactured by Sumitomo Osaka Cement Co., Ltd.) and an average particle size of about 30 nm AZ-SW (trade name, manufactured by Osaki Industry Co., Ltd.) of a 200 nm zinc white emulsion was used.

The evaluation results of the latex compositions obtained in Examples 1 and 2 and Comparative Example 1 are shown in Table 1.

[0031]

[Table 1]

Examples 3 and 4 and Comparative Example 2 Chloroprene latex was prepared by using potassium persulfate as a catalyst under a nitrogen atmosphere at the formulation and polymerization temperature shown in Table 2.
% Thiodiphenylamine was added to the initial chloroprene monomer 1
The reaction was stopped by adding 0.02 parts by weight to 00 parts by weight. After the polymerization, the monomers were removed under reduced pressure, and the solid content was adjusted to 50% under reduced pressure while heating.

The resulting chloroprene latex was blended according to the formulation shown in Table 2 to obtain adhesive compositions of Examples 3, 4 and Comparative Example 2. The unit of the compounding amount is part by weight of the solid content. As zinc white, ZW-101 of a fine particle zinc white emulsion having an average particle size of about 10 nm as shown in Table 2 was used.
(Sumitomo Osaka Cement Co., trade name), average particle size about 30n
m ZW-143 (trade name, manufactured by Sumitomo Osaka Cement Co., Ltd.) and AZ-SW (trade name, manufactured by Osaki Industry Co., Ltd.) having an average particle diameter of 200 nm were used. As the tackifier, terpene-modified phenol resin emulsion Tamanol E-100 (trade name, manufactured by Arakawa Chemical Industries, Ltd.) was used.

The evaluation results of the adhesive compositions obtained in Examples 3, 4 and Comparative Example 2 are shown in Table 2.

[0035]

[Table 2]

[0036]

As is clear from Tables 1 and 2, the chloroprene latex composition and the adhesive composition containing finely divided zinc white according to the present invention are the same as the conventional latex composition containing zinc white with large particle size. Excellent in heat resistance and weather resistance as compared with the adhesive composition.

Claims (4)

[Claims] 1. A chloroprene polymer having an average particle size of 200
A chloroprene latex composition containing fine particles of zinc white having a particle diameter of less than nm. 2. A method according to claim 1, wherein 100 parts by weight of the chloroprene polymer is mixed with fine particles of zinc oxide having an average particle diameter of less than 200 nm in an amount of 0.0
The chloroprene latex composition according to claim 1, which is contained in an amount of 5 to 30 parts by weight. 3. The chloroprene latex composition according to claim 1, wherein the chloroprene polymer is a carboxyl-modified chloroprene polymer obtained by copolymerizing one or more monomers containing a carboxyl group. 4. An adhesive composition comprising the chloroprene latex composition according to any one of claims 1 to 3.