JP2000256512A - Polychloroprene latex composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polychloroprene latex composition and a method for producing a polychloroprene latex adhesive composition which contain a phenolic antioxidant and do not yellow in the dark. SOLUTION: A polychloroprene latex composition and a polychloroprene adhesive composition comprising (A) a polychloroprene latex, (B) a phenolic antioxidant, and (C) a thiourea-based compound. The amount of the component B is preferably 0.01 to 20 parts by weight, and the amount of the component C is suitably 0.01 to 20 parts by weight based on 100 parts by weight of the solid content of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be used for fiber-treated products such as non-woven fabric binders, dipped products and adhesive products,
The present invention relates to a polychloroprene latex composition having excellent yellowing resistance in a dark place, an adhesive and a binder obtained therefrom, and a polychloroprene latex composition containing a phenolic antioxidant and a thiourea-based compound and having improved dark yellowing in the dark place. And an adhesive composition obtained therefrom,
It is a binder composition.

[0002]

2. Description of the Related Art Polychloroprene polymers have a disadvantage that they are easily discolored by light or heat. For this reason,
Various phenolic antioxidants may be used for the polychloroprene latex composition and the polychloroprene latex adhesive composition in order to improve light stability and heat stability. However, the polychloroprene latex composition and the polychloroprene latex adhesive composition containing a phenolic antioxidant may cause yellowing in a dark place during long-term storage under high temperature and high humidity.

[0003] Accordingly, there has been a need for a method of improving the yellowing in a dark place of a polychloroprene latex composition and a polychloroprene latex adhesive composition containing a phenolic antioxidant.

[0004]

SUMMARY OF THE INVENTION The present invention solves the problems of such polychloroprene latex composition and polychloroprene latex adhesive composition. It is an object of the present invention to provide a polychloroprene latex composition and a polychloroprene latex adhesive composition that are less likely to cause deformation.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a polychloroprene latex composition containing a phenolic antioxidant and a polychloroprene latex adhesive composition Even so, it has been found that by adding a thiourea-based compound, it is possible to make it difficult to cause yellowing in a dark place, and the present invention has been completed.

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

The monomer copolymerizable with chloroprene in the present invention includes, for example, 2,3-dichloro-1,3-
Examples thereof include butadiene, 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 emulsifier and / or dispersant used in the emulsion polymerization in the present invention is not particularly limited, and various anionic, nonionic and cationic types can be used.
Examples of the emulsifier used for the anionic latex 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 the like. Specific examples of the nonionic type include a water-soluble polymer, an ether type, an ester type, a sorbitan ester type, a sorbitan ester ether type, an alkylphenol type and the like.For example, polyvinyl alcohol, polyoxyethylene tridecyl ether, polyoxyethylene mono Stearate, sorbitan monooleate and the like can be mentioned. 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 emulsion polymerization 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. When the amount is less than 1 part by weight, the emulsifying power is insufficient, and when the amount is more than 20 parts by weight, when the obtained polychloroprene latex composition is used for an aqueous adhesive, the adhesive strength is reduced.

The polychloroprene latex composition of the present invention is prepared by adding a phenolic antioxidant and a thiourea compound to an emulsion polymerization solution containing the above chloroprene polymer obtained by emulsion polymerization according to the following method. Can be obtained by: 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. This makes it possible to adjust the solid content concentration, the molecular weight of the toluene-soluble portion, the gel content, and the like.

The polymerization temperature of the chloroprene polymer in the present invention is not particularly limited. The polymerization catalyst is a sulfated salt 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.

[0014] The final polymerization rate is not particularly limited and can be adjusted arbitrarily. Unreacted monomers are removed by a demonomerization operation, but the method is not particularly limited. By concentrating or diluting by adding water or the like, the solid content concentration can be controlled to a necessary concentration. Concentration methods include vacuum concentration,
There is no particular limitation.

Specific examples of the phenolic antioxidant in the present invention include 2,6-di-t-butyl-4-methylphenol (commonly called BHT) and 2,6-di-t-butyl- 4-ethylphenol, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4
-Ethyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t
-Butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), a butylated reaction product of p-cresol and dicyclopentadiene, 1,1-bis (4-hydroxyphenyl) cyclohexane, tetrakis [Methylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 3,9-
Bis [2- {3- (3-t-butyl-4-hydroxy-
5-methylphenyl) -propionyloxy} -1,1-
Dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, triethylene glycol-
Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3
5-di-t-butyl-4-hydroxy-benzyl) -isocyanurate and the like, and two or more phenolic antioxidants may be used in combination.

The method of adding / mixing the phenolic antioxidant in the present invention is not particularly limited. Addition /
As a compounding method, there are a method of adding as a powder, a method of dispersing in water and adding as an emulsion, and a method of adding a solution dissolved in an organic solvent such as toluene. Most of the phenolic antioxidants are crystalline powders, and can be easily pulverized into fine powders by a ball mill or the like.

The amount of the phenolic antioxidant (may be a mixture of two or more phenolic antioxidants) according to the present invention depends on the required performance, but is preferably 0 to 100 parts by weight of polychloroprene. 0.01 to 20 parts by weight is preferred.

Specific examples of the thiourea compound in the present invention include ethylenethiourea, dibutylthiourea, dilaurylthiourea, N, N'-diphenylthiourea, trimethylthiourea (usually called TMU), and N, N'-diethylthiourea ( (Usually called EUR)). Of these, two or more thiourea-based compounds may be used as a mixture. Ethylenethiourea is most effective in improving yellowing in the dark.

The method of adding / compounding the thiourea compound in the present invention is not particularly limited. Examples of the addition / blending method include a method of adding as a powder, a method of dispersing in water and adding as an emulsion, and a method of adding a solution dissolved in an organic solvent such as toluene. The thiourea-based compound is hard to be pulverized into a fine powder by a ball mill or the like, and it is difficult to prepare an emulsion.

The addition amount of the thiourea compound (may be a mixture of two or more thiourea compounds) in the present invention depends on the required performance. 0.01
-20 parts by weight are preferred.

It is essential that the polychloroprene latex composition of the present invention contains a phenolic antioxidant and a thiourea-based compound, but the compounding agent usually added to the latex, for example, a metal oxide, a thickener ( Viscosity modifier), filler, PH regulator, antibacterial agent, fungicide, ultraviolet absorber, tackifier resin, vulcanizing agent, vulcanization accelerator, curing agent,
Preservatives, non-phenolic antioxidants, defoamers, rust inhibitors and the like can be optionally added. When the polychloroprene latex composition of the present invention is used as an adhesive composition, an adhesive composition having a good balance of adhesion performance can be obtained by adding a tackifier resin. Specific examples of the tackifying resin include rosin resin, rosin ester resin, hydrogenated rosin resin, polymerized rosin resin, α-pinene resin, β-pinene resin, terpene phenol resin, C ₅
Distillate petroleum resin, C ₉ distillate petroleum resin, C ₅ / C ₉ distillate petroleum resin, DCPD petroleum resin, alkylphenol resin, xylene resin, cumarone resin, cumarone indene resin and the like.

[0022]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The yellowing in the dark and the properties of the latex were evaluated by the following methods.

[Evaluation Test for Yellowing in a Dark Place] A polychloroprene latex composition or a polychloroprene latex adhesive composition was applied to a white EVA foam plate with a brush, and dried at 23 ° C. for 3 hours. Created. Constant temperature / humidity chamber PR-3ST (Tabayspec)
Was set to a temperature of 40 ° C. and a relative humidity of 80%, and the test pieces were stored. The storage periods are 300 hours and 500 hours.

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

[Weight-Average Molecular Weight of Soluble Part] Polychloroprene latex was freeze-dried, dissolved in THF, and filtered through a filter to separate a sol. The separated sol was adjusted to a 0.1% by weight THF solution, and GPC measurement was performed under the following conditions. The molecular weight was calculated in terms of polystyrene. Column: PL gel 10 μm GUARD + PL gel 1
0 μM Mixed-B × 3 columns Column size: 7.5 mmΦ × 50 mm (GUAR
D), 7.5 mmΦ × 300 mm (Mixed-B) Column temperature: 35 ° C., solvent: THF, Outflow rate: 1 ml / min Detector: SHIMAZU RID-6A

[Measurement of Gel Content] A latex sample was freeze-dried and 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 was air-dried and then dried for 1 hour in a 110 ° C. atmosphere. The gel content (%) was calculated according to the following equation. Gel content = (B / A) × 100

[Normal Adhesion Performance Evaluation Test] An adhesive composition was blended and prepared according to the formulation shown in Table 1. Next, 150 g (wet) / m ² of the adhesive composition was applied to each of two canvases (size of the margin portion: width 25 mm × length 70 mm) with a brush, and dried in a 23 ° C. atmosphere for 3 hours. After that, an adhesive composition of 200 g (wet) / m ² was applied from above with a brush and dried at 70 ° C. for 5 minutes. Further, an adhesive composition of 200 g (wet) / m ² was applied again by a brush, dried in an atmosphere of 70 ° C. for 5 minutes, bonded together, and pressed with a hand roller. After curing for 1 day from pressure bonding in an atmosphere of 23 ° C, pulling speed 200mm with a tensile tester
/ Min was measured at 180 ° peel strength.

[Evaluation Test of Water-Resistant Adhesive Performance] An adhesive composition was blended and prepared according to the formulation shown in Table 1. Next, 150 g (wet) / m ² of the adhesive composition was applied to each of two canvases (size of the margin portion: width 25 mm × length 70 mm) with a brush, and dried in a 23 ° C. atmosphere for 3 hours. After that, an adhesive composition of 200 g (wet) / m ² was applied from above with a brush and dried at 70 ° C. for 5 minutes. Further, an adhesive composition of 200 g (wet) / m ² was applied again by a brush, dried in an atmosphere of 70 ° C. for 5 minutes, bonded together, and pressed with a hand roller. After curing for 1 day from the pressure bonding in an atmosphere of 23 ° C., it was immersed in water of 23 ° C. for 2 days, and the 180 ° peel strength was measured at a tensile speed of 200 mm / min by a tensile tester.

Examples 1 and 2 and Comparative Examples 1 and 2 Polychloroprene latex was prepared by using potassium persulfate as a catalyst under a nitrogen atmosphere at a polymerization temperature of 10 ° C. shown in Table 1.
% Aqueous solution was added, and n-dodecyl mercaptan was used as a serial transfer agent so as to have a weight average molecular weight of 540,000, a gel content of 15%, and a solid content of 60 wt% shown in Table 1.

The resulting latex was blended according to the formulation shown in Table 1 to obtain polychloroprene latex compositions and polychloroprene latex adhesive compositions of Examples 1-2 and Comparative Examples 1-2. The unit of the compounding amount is a solid content part by weight.

Examples of the phenolic antioxidant include n-octadecyl-3- (3,5-dibutyl-4-hydroxyphenyl) propionate (trade name: Cellozol F-7)
73 / Chukyo Yushi Co., Ltd.). Cellozol F-
773 is an emulsion product having a solid content of 50%.
As the thiourea-based compound, ethylene thiourea (trade name: Axel 22-S / Kawaguchi Chemical Co., Ltd.) was added as powder.

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

[0033]

[Table 1]

Note 1) Terpene phenol resin emulsion, trade name: Tamanol E-100 (manufactured by Arakawa Chemical Industries, Ltd.) Note 2) n-octadecyl-3- (4-hydroxy-3,
5-Di-t-butylphenyl) propionate, trade name: Cellosol F-773 (manufactured by Chukyo Yushi Co., Ltd.) Note 3) Ethylenethiourea, trade name: Axel 22-S
(Kawaguchi Chemical Co., Ltd.)

As apparent from Table 1, the polychloroprene latex composition and the adhesive composition of the present invention (Example 1)
2) did not cause yellowing in a dark place, unlike the conventional latex compositions (Comparative Examples 1 and 2). In addition, it was confirmed by a peeling test that the adhesion performance (particularly, water resistance and normal state adhesion) was improved when a thiolurea compound was added to the polychloroprene latex adhesive composition containing the polychloroprene latex and the tackifier resin emulsion.

[0036]

Industrial Applicability The polychloroprene latex composition of the present invention and the adhesive composition and binder composition obtained therefrom have improved yellowing in a dark place and improved adhesion performance (particularly water resistance and normal adhesion). It is extremely useful as a polychloroprene latex composition used for adhesives, binders and the like.

Claims (4)

[Claims] 1. A polychloroprene latex composition comprising polychloroprene, a phenolic antioxidant, and a thiourea compound. 2. A phenolic antioxidant is used in an amount of 0.01 to 20 parts by weight, based on 100 parts by weight of polychloroprene.
The polychloroprene latex composition according to claim 1, wherein the composition contains 0.01 to 20 parts by weight of a thiourea-based compound. 3. An adhesive composition comprising the polychloroprene latex composition according to claim 1 or 2. 4. A binder composition comprising the polychloroprene latex composition according to claim 1 or 2.