JP2003138066A - Polychloroprene-based latex composition, aqueous primer, and bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polychloroprene-based latex composition suitable as the main raw material for an aqueous primer and an aqueous adhesive which gives the bonding strength equal to the solvent based primers and adhesives used conventionally. SOLUTION: The polychloroprene-based latex composition has a polychloroprene and sodium orthosilicate as the essential components which are dispersed or dissolved in water. The polychloroprene-based latex composition additionally comprises a tackifying resin which is jointly dispersed or dissolved in water. The bonding method comprises bonding adherends with the use of the polychloroprene-based composition or an aqueous primer comprising the same.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention exhibits good adhesive strength to adherends such as rubber, elastomers and synthetic resins, and is useful as a main raw material for water-based adhesives and water-based primers used for these adherends. A polychloroprene-based latex composition is provided.

[0002]

2. Description of the Related Art Conventionally, solvent-based primers and adhesives have been mainly used as a method for adhering a difficult-to-adhere adherend such as rubber, elastomer and synthetic resin. However, in the case of the solvent system, since a large amount of organic solvents such as toluene, ethyl acetate and methyl ethyl ketone are used, it is not preferable in terms of worker safety and health and environment. for that reason,
The demand for water-based adhesives and primers has been increasing year by year, and for example, Japanese Patent Laid-Open Nos. 2001-64616 and 200
Several proposals have been made, such as 1-26756. However, it was the current situation that the adhesive strength was still insufficient for practical use.

[0003]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is suitable for use as a main raw material for water-based primers and water-based adhesives that provide adhesive strength comparable to that of solvent-based primers and adhesives that have been conventionally used. It is intended to provide a chloroprene latex composition.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that polychloroprene and sodium orthosilicate are essential components, and poly or polychloroprene and sodium orthosilicate are dispersed or dissolved in water. The inventors have found that the chloroprene latex composition gives excellent adhesion strength to adherends such as rubber, elastomers and synthetic resins, and have completed the present invention.

That is, the present invention is a polychloroprene-based latex composition comprising polychloroprene and sodium orthosilicate as essential components, which are dispersed or dissolved in water. A polychloroprene-based latex composition comprising polychloroprene and sodium orthosilicate as essential components, a tackifying resin added thereto, and those dispersed or dissolved in water. Furthermore, it is an adhesion method for adhering an adherend using these polychloroprene latex composition or water-based primer.

The details of the present invention will be described below. The polychloroprene referred to in the present invention means 2-chloro-1,3
A butadiene (hereinafter referred to as “chloroprene”) homopolymer or a copolymer of chloroprene and a monomer copolymerizable with chloroprene. The term "copolymer" as used herein also includes a graft copolymer obtained by graft-polymerizing another monomer in the presence of polychloroprene.

Examples of the monomer copolymerizable with chloroprene include 2,3-dichloro-1,3-butadiene,
Examples thereof include 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and two or more kinds may be used as necessary.

The method for polymerizing polychloroprene is not particularly limited, but the method by emulsion polymerization is general and simple. In order to complete the present invention, it is necessary to disperse polychloroprene in water,
In the case of emulsion polymerization, the obtained polychloroprene latex can be used as it is.

The emulsifier and / or dispersant used in the emulsion polymerization of the polychloroprene latex is not particularly limited, and various anionic type, nonionic type and cation type that are usually used in chloroprene latex can be used. Anionic emulsifiers include carboxylic acid type,
Examples thereof include sulfonic acid type and sulfuric acid ester type, and examples thereof include alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkylaryl sulfates, condensates of sodium naphthalenesulfonate and formaldehyde, and the like. Specific examples of the nonionic type include polyvinyl alcohol or its copolymer (for example, copolymer with acrylamide), polyvinyl ether or its copolymer (for example, copolymer with maleic acid), polyvinylpyrrolidone or its copolymer. 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 cation type include an aliphatic amine salt and an aliphatic quaternary ammonium salt. Examples thereof include octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride and dilauryldimethylammonium chloride.

The addition amount of the emulsifier and / or dispersant in the polychloroprene latex of the present invention is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the total amount of the initially charged monomers. If it is less than 0.5 parts by mass, the emulsifying power is not sufficient, and if it exceeds 20 parts by mass, there is a drawback that the water-resistant adhesive strength is lowered.

The polymerization temperature of the polychloroprene latex in the present invention is not particularly limited, but in order to smoothly carry out the polymerization reaction, the polymerization temperature is preferably 0 to 50 ° C. As a polymerization initiator, a persulfate such as potassium persulfate, an organic peroxide such as tert-butyl hydroperoxide, or the like is preferably used, but it is not limited thereto.

The type of chain transfer agent used for the polymerization is not particularly limited, and those usually used for emulsion polymerization of chloroprene can be used. For example, long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide, and known chain transfer agents such as iodoform can be used.

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

The final polymerization rate of polychloroprene is not particularly limited and can be arbitrarily adjusted, and unreacted monomers are removed by the demomer operation.
The method is not particularly limited. The solid content concentration of the polychloroprene latex of the present invention can be controlled to a required concentration by concentrating or diluting it by adding water or the like. The concentration method includes concentration under reduced pressure, but is not particularly limited.

The structure of the polychloroprene latex in the present invention is not particularly limited, but the polymerization temperature, polymerization initiator, chain transfer agent, polymerization terminator, final polymerization rate, demonomer, concentration conditions, etc. are suitable. It is possible to adjust the solid content concentration, the molecular weight of the toluene soluble portion, the toluene insoluble content (gel content) and the like by selecting and controlling the above.
From the viewpoint of the balance between the initial adhesive strength and the normal adhesive strength, it is preferable to adjust the gel content of the (co) polymer in the polychloroprene latex to 3 to 60% by weight.

Sodium silicate has the general formula Na ₂ O.nS
represented by iO ₂ · mH ₂ O, the molar ratio of Na ₂ O and SiO ₂ ,
That is, it is divided into sodium orthosilicate, sodium metasilicate, sodium silicate No. 1, sodium silicate No. 2, sodium silicate No. 3, sodium silicate No. 4, etc. according to the coefficient n. In the present invention, sodium orthosilicate is particularly used. To be The amount of sodium silicate added is
Although not specified, from the viewpoint of adhesive strength,
0.1 per 100 parts by weight of polychloroprene (solid content)
The amount is preferably -30 parts by weight, more preferably 1-15 parts by weight.

The polychloroprene latex composition of the present invention, which contains polychloroprene and sodium orthosilicate as essential components and is dispersed or dissolved in water, exhibits sufficient adhesive strength as it is, but the initial adhesive strength, In order to make properties such as water resistant adhesive strength and tack retention time more practical, it is effective to further add tackifying resin.

When compounding a tackifying resin with an aqueous adhesive
However, the type is not particularly limited. Specifically
Is rosin resin, polymerized rosin resin, α-pinene resin, β
-Pinene resin, terpene phenol resin, C_FiveFractional stone
Oil resin, C₉Fraction petroleum resin, C _Five/ C₉Fractionated petroleum tree
Oil, DCPD petroleum resin, alkylphenol resin, ki
Siren resin, coumarone resin, coumarone indene resin, etc.
Is mentioned. Softening to get sufficient initial adhesion
A resin having a point temperature of 50 to 160 ° C. is preferable.

The method of adding the tackifying resin is not particularly limited, but it is preferable to add it as an aqueous emulsion in order to uniformly disperse the resin in the latex. Further, a method for producing an aqueous emulsion of a tackifying resin includes a method of emulsifying / dispersing a substance dissolved in an organic solvent such as toluene in water using an emulsifier, and then removing the organic solvent by heating under reduced pressure and removing fine particles. Although there is a method of pulverizing into 2 to emulsify / disperse, the former is preferable because it can produce an emulsion of finer particles.

The solid content concentration of the polychloroprene latex composition of the present invention is not particularly limited, but 70% by weight or less is preferable in order not to impair the stability of the emulsion system. Further, when the polychloroprene-based latex composition of the present invention is used as a water-based adhesive, it is 40-
70% by weight, when used as an aqueous primer, it is preferable to adjust the solid content concentration to 10 to 40% by weight, but the solid content is adjusted by diluting with pure water or removing water. It can be optionally performed by concentration.

In addition to the above, the polychloroprene latex composition according to the present invention has a thickener, a metal oxide, a filler, a film-forming aid, an ultraviolet absorber, an antioxidant, in addition to the above-mentioned properties. A plasticizer, a vulcanizing agent, a vulcanization accelerator, a defoaming agent, etc. can be optionally added.

The polychloroprene latex composition of the present invention can be adjusted to an arbitrary viscosity by adding a thickener. Specific thickeners include polyvinyl alcohol (PVA), sodium polyacrylate,
Water-soluble polyurethane, associative polyurethane emulsion, alkali swelling acrylic emulsion, carboxymethyl cellulose (CMC), methyl cellulose (M
C), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), polyvinyl alcohol, synthetic smectite and the like. The compounding amount of the thickener is 100% by solid content of polychloroprene latex.
0.01 to 10 parts by mass (solid content conversion) is suitable for the parts by mass. By blending in this range, the viscosity of the polychloroprene latex composition can be adjusted without adversely affecting the adhesive properties.

The materials such as rubber, elastomer and synthetic resin to which the polychloroprene latex composition of the present invention is applied are not particularly limited, but specifically,
Butadiene rubber (BR), chloroprene rubber (CR),
Natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butyl rubber (IIR),
Norbornene rubber (NOR), nitrile rubber (NB
R), hydrogenated nitrile rubber (HNBR), brominated butyl rubber (BIIR), chlorinated butyl rubber (CIIR), acrylonitrile-isoprene copolymer (NIR), ethylene-propylene-diene rubber (EPDM), vulcanized rubber, Styrene-butadiene-styrene-block copolymer (SBS), polyester-based, urethane-based, olefin-based thermoplastic elastomer, vinyl chloride resin (P
VC), ethylene-vinyl acetate copolymer (EVA), 1,2-
Examples include polybutadiene (RB), polyolefin resin, styrene resin, acrylonitrile-butadiene-styrene copolymer (ABS), and the like. Further, the compounding composition, cross-linking density, shape and the like of these materials are not particularly limited, and a foam can be applied. It can be preferably used in any field such as grips of sports equipment, shoe soles, building materials, etc.

[0024]

EXAMPLES The effects of the present invention will be described in detail below with reference to examples and comparative examples, but these examples do not limit the present invention. In the following description, parts and% are based on mass unless otherwise specified.

[Experimental Example 1] Using a reactor having an internal volume of 3 liters, under a nitrogen stream, 100 parts of water and 5 parts of disproportionated rosin acid.
Parts, sodium hydroxide 0.6 parts, potassium hydroxide 0.7
Parts, 0.3 parts of sodium salt of formaldehyde naphthalene sulfonic acid condensate, and 0.3 parts of sodium bisulfite were charged, and after dissolution, chloroprene monomer 1 was stirred.
00 parts and 0.14 parts of n-dodecyl mercaptan were added. Polymerization was carried out at 10 ° C. in a nitrogen atmosphere using potassium persulfate as an initiator, and when the polymerization rate reached 90%, an emulsion of phenothiazine was added to terminate the polymerization. Unreacted monomers were removed under reduced pressure to obtain polychloroprene latex. Further, water was evaporated under reduced pressure to concentrate the solution, and the solid content was adjusted to 50% by mass.

Example 1 Using the polychloroprene latex obtained in Experimental Example 1, a solid content concentration of 53 as a tackifying resin was added to 100 parts of the polychloroprene latex.
% Terpene phenolic resin emulsion (Tamanor E
-100 / manufactured by Arakawa Chemical Industry Co., Ltd.) and 3 parts of sodium orthosilicate solution (manufactured by Asahi Denka Kogyo Co., Ltd.) having a solid content of 30% were added to prepare a chloroprene water-based adhesive.

Vulcanized styrene butadiene rubber (sulfurized vulcanized SBR, the size of the glue margin is 20 mm wide) after buffing (adhesive polishing) the adhesive surface and removing shavings by washing with acetone.
A 200 g (wet) / m ² chloroprene water-based adhesive was applied to the surface of (× length 70 mm) with a brush, dried in an atmosphere at 60 ° C. for 6 minutes, and then laminated and pressure-bonded with a hand roller. The test pieces obtained by this method were evaluated as follows. [Initial Adhesive Strength Evaluation Test] Ten minutes after pressure bonding, T-type peel strength was measured with a tensile tester at a tensile speed of 200 mm / min. [Normal-state adhesive strength evaluation test] One day after pressure bonding, the T-type peel strength was measured with a tensile tester at a tensile speed of 200 mm / min.

[Comparative Example 1] Comparative Example 1 was carried out by conducting the same tests as in Example 1 except that sodium orthosilicate was not used.

[Comparative Examples 2 to 4] Tests were carried out in the same manner as in Example 1 except that sodium silicate of another type was used instead of sodium orthosilicate, and Comparative Examples 2 to 4 were obtained.

The results obtained are shown in Table 1.

[0031]

[Table 1]

[0032]

As is apparent from Tables 1 and 2, the polychloroprene latex composition of the present invention exhibits good adhesive strength and can be suitably used as an aqueous primer or an aqueous adhesive.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 111/02 C09J 111/02 F term (reference) 4J002 AC091 AF022 BA012 BK002 BN141 CC052 CC122 DJ006 FD330 GH00 GJ01 HA06 4J038 CA021 CA131 MA08 MA10 PC07 PC08 4J040 BA202 CA151 DK012 DN032 DN072 EB052 EB082 EL012 HA316 JA03 KA26

Claims (4)

[Claims] 1. A polychloroprene-based latex composition comprising polychloroprene and sodium orthosilicate as essential components, which are dispersed or dissolved in water. 2. The polychloroprene latex composition according to claim 1, wherein the content of sodium orthosilicate is 1 to 15 parts by weight based on 100 parts by weight of polychloroprene. 3. The polychloroprene latex composition according to claim 1, further comprising a tackifying resin. 4. A bonding method for bonding an adherend using the polychloroprene latex composition according to claim 1.