JPH10158312A - Production of chloroprene rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a chloroprene rubber, excellent in light-colored hue, tack, heat aging and ultraviolet light resistances and useful for adhesives, etc., by carrying out the aqueous radical emulsion polymerization of a mixture such as chloroprene under specific conditions. SOLUTION: The aqueous radical emulsion polymerization of chloroprene or its mixture with a monomer copolymerizable therewith is carried out by using an alkali metallic salt of a disproportionated resin acid in an amount of preferably 2-6 pts.wt. (based on 100 pts.wt. total monomer) and an organic amine salt of a water-soluble polymer containing sulfonate groups such as a polymer having a styrenesulfonic acid structure having 1×10<3> to 5×10<4> weight- average molecular weight of a sulfonic acid group-containing monomer introduced thereinto according to an addition polymerization and/or polymeric reaction after the addition polymerization in an amount of preferably 0.1-2 pts.wt. based on 100 pts.wt. total monomer as a dispersing agent to afford a chloroprene rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel method for producing chloroprene rubber. More specifically, the present invention relates to a method for producing a chloroprene rubber having extremely excellent light-colored hue and tackiness capable of maintaining tackiness for a long time after application of an adhesive when used as an adhesive.

[0002]

2. Description of the Related Art Chloroprene rubber is commonly used as a raw material for adhesives because of its high crystallinity and high cohesive strength. Dissolve chloroprene rubber in organic solvents such as toluene and methyl ethyl ketone among various adhesive applications,
A so-called solution-grafted chloroprene rubber adhesive obtained by adding a monomer such as methyl methacrylate and performing a graft polymerization reaction using a radical polymerization initiator such as benzoyl peroxide is useful for bonding a soft PVC-based material. This is known, and because of its excellent adhesiveness, it has been widely used as an adhesive for synthetic shoes.

The method for producing chloroprene rubber has been known for a long time, and known methods include, for example, Encyc
loopedia of Polymer Science
end Engineering, 2nd ed. ,
Vol. 3, Wiley-Interscience,
New York, 1985, p447-449.

The chloroprene rubber obtained by this method generally has a yellow-brown color, and its L value, a value and b value are 65 to 75 and −2.0 to
-3.0, 10.0 to 16.0. In the adhesive prepared using such chloroprene rubber, the adhesive solution shows a value of 0.4 to 0.6 as measured by the absorbance for yellowness, and is excellent in the transparent and colorless color required for bonding synthetic shoes. Hue cannot be sufficiently satisfied.

[0005] Therefore, for the purpose of improvement, JP-B-57-34844 discloses that emulsion polymerization is carried out using an alkali metal salt of disproportionated rosin acid and an additional surfactant as an emulsifier. A method is disclosed. Especially,
It is characterized in that a specific surfactant is used as an additional surfactant. For example, alkylsulfonic acid alkali salts of C ₁₂ -C _15, 1,3-bis - (2-ethylhexyl) glycerol ether sulfates alkali salts, alpha
- hydroxy - octadecanoic acid alkali salts, ferric -C ₁₂ -C ₁₄ alkyl sulfate alkali salts, monolaurate glyceride sulfate alkali salts, N-
There are descriptions of octadecyl sulfosuccinic acid amide alkali salts and the like.

According to this method, the hue is sufficiently improved, but the tackiness, which is a characteristic when an alkali metal salt of a condensate of naphthalenesulfonic acid and formaldehyde is used, becomes insufficient, and the chloroprene rubber adhesive is used. Charm disappears.

Under the circumstances described above, development of a chloroprene rubber adhesive having both hue and tackiness is urgently required. However, at present, it has not been possible to provide a material which can sufficiently satisfy the requirements of the market. Not in.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a chloroprene rubber having a very excellent light-colored hue and tackiness, which cannot be obtained with a conventional chloroprene rubber adhesive.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies based on such a background, and as a result, have completed the present invention. That is, the present invention relates to an aqueous radical emulsion polymerization of chloroprene or a mixture of chloroprene and a monomer copolymerizable with chloroprene, together with an alkali metal salt of disproportionated rosin acid. A process for producing chloroprene rubber, which comprises using, as a dispersant, an organic amine salt of a water-soluble polymer containing a sulfonic acid group introduced by a molecular reaction. In particular, when the organic amine used for the organic amine salt of the water-soluble polymer containing a sulfonic acid group is hardly soluble or insoluble in water, and when the organic amine is a polymer having a styrenesulfonic acid structure, the present invention This is a method for producing chloroprene rubber which can exhibit the characteristics of (1) most effectively.

Hereinafter, the present invention will be described in detail.

The monomer used as the rubber polymer raw material in the present invention may be chloroprene alone or in an amount of up to 50% by weight of chloroprene, for example, an unsaturated carboxylic acid ester compound such as an acrylate or a methacrylate. Carboxylic acid compounds such as acrylic acid, methacrylic acid, itaconic acid and maleic acid; vinyl-substituted aromatic compounds such as styrene and vinyltoluene; conjugated dienes such as butadiene, 1-chlorobutadiene and 2,3-dichlorobutadiene. Examples include monomers containing compounds, polar group-containing vinyl compounds such as acrylonitrile, methacrylonitrile, vinyl chloride, and vinylidene chloride.

The alkali metal salt of disproportionated rosin acid in the present invention is not particularly limited as long as it can exhibit a sufficient function as an emulsifying dispersant in chloroprene emulsion polymerization. Examples of the alkali metal salt of disproportionated rosin acid include sodium salts and potassium salts of disproportionated rosin acids, which can be obtained, for example, by disproportionation of wood resin and wood rosin. . The disproportionated rosin acid which is a component of the alkali metal salt has a molecular weight of 500 since rosin acid itself is pale.
It is preferable to use disproportionated rosin acid composed of the following components, and in order to make the hue improvement effect of the present invention more remarkable, use disproportionated rosin acid distilled under reduced pressure under a nitrogen blanket. More preferably, The amount of the alkali metal salt of disproportionated rosin acid is not particularly limited. For example, it is preferably 2 to 6 parts by weight per 100 parts by weight of the monomer used as the rubber polymer raw material, and is preferably 3 to 6 parts by weight.
~ 5.5 parts by weight is more preferred. Within this range, the stability of latex particles during emulsion polymerization can be sufficiently ensured, solid rubber precipitation due to physical external pressure in the finishing step is not observed, and the hue is in a very excellent range.

In the present invention, the use of an organic amine salt of a water-soluble polymer containing a sulfonic acid group introduced by addition polymerization and / or a polymer reaction after addition polymerization as a dispersant has a great effect. is there. In particular, by using an amine whose organic amine is hardly soluble or insoluble in water, a water-soluble polymer containing a sulfonic acid group can appropriately have both hydrophilicity and hydrophobicity. preferable. Further, when the dispersant has a styrene sulfonic acid skeleton, the balance between hydrophilicity and hydrophobicity is further improved, and the effect is most exhibited.

The organic amine used for the organic amine salt of the water-soluble polymer containing a sulfonic acid group in the present invention is not particularly limited as long as it satisfies the object of the present invention.
Examples of amines that are hardly soluble or insoluble in water include, for example, trimethylamine, triethylamine, diisopropylamine, n-dibutylamine, n-tributylamine, diisobutylamine, diamylamine, triamylamine, 2-ethylbutylamine, n-heptylamine , 2-ethylhexylamine, dioctylamine and the like.

The method for producing a water-soluble polymer containing an organic amine salt of sulfonic acid introduced by addition polymerization and / or a polymer reaction after addition polymerization in the present invention includes, for example, unsaturated polymerization capable of radical polymerization and ionic polymerization. It is obtained by homopolymerizing or copolymerizing a monomer having a double bond. Regarding the introduction of the sulfonic acid group, a compound contained at the stage of the monomer may be selected, or a method of introducing the sulfonic acid group by a polymer reaction after polymerization may be used. Similarly, the introduction of the organic amine salt may be carried out either when the organic amine salt is contained at the monomer stage or when the reaction is carried out after the polymerization.

Examples of the monomer for obtaining the water-soluble polymer as the dispersant of the present invention include the following examples. As monomers containing a sulfonic acid group, allylsulfonic acid and its organic amine salt, methallylsulfonic acid and its organic amine salt, vinylsulfonic acid and its organic amine salt, 2-acrylamido-2-methylpropanesulfonic acid and Acrylic acid esters, methacrylic acid esters, p-vinylbenzylsulfonic acid and its organic amine salts, styrenesulfonic acid and its organic amine salts as monomers capable of introducing sulfonic acid by post-sulfonation. Unsaturated carboxylic acid compounds such as acrylic acid, methacrylic acid, and maleic anhydride; unsaturated carboxylic acid amide compounds such as acrylamide, methacrylamide, and propylacrylamide; and vinyl substitution such as styrene and vinyltoluene. Type aromatic compounds, Ronitoriru, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl chloride, mention may be made of a polar group-containing vinyl compounds such as vinylidene chloride and the like. The organic amine salt of a polymer having a styrene sulfonic acid structure has a good balance of hydrophobicity and hydrophilicity, so that it is excellent in dispersing effect with a small amount of addition, and has good hue and tackiness. It is suitable. The above monomers can be selected from homopolymers and copolymers as long as the properties of the present invention can be exhibited.

The method for synthesizing the organic amine salt of a water-soluble polymer as the dispersant of the present invention can be in accordance with conventional radical polymerization or ionic polymerization. For example, in the case of radical polymerization of a monomer containing a sulfonic acid group, in a water, a mixed solvent of water / alcohol or a polar solvent such as dimethylformamide or dimethylsulfoxide, a persulfate or an azo compound is used. It can be carried out by solution polymerization by adding a suitable radical initiator or a molecular weight regulator such as mercaptan. Further, for example, when a sulfonic acid group is introduced by a polymer reaction, it can be synthesized by dissolving a resin such as polystyrene in a solvent such as ethylene dichloride and feeding liquid sulfur trioxide into the solution.

When the organic amine salt of the water-soluble polymer as the dispersant in the present invention is a copolymer, the introduction ratio of the sulfonic acid group-containing monomer in the water-soluble polymer is sufficient for the effect of the present invention. Although it is not limited as long as it can be exhibited and is water-soluble, it is not less than 10 mol%, preferably 3 mol%.
0 mol% or more, more preferably 50 mol% or more, is preferable because the effect is more remarkably exhibited. Also, the molecular weight of the organic amine salt of the water-soluble polymer is not limited as long as the effect can be sufficiently exhibited, but the weight average molecular weight is preferably 1 × 10 ^{3 to} 5 × 10 ⁴ , × 10 ³ to 1 × 10 ⁴ is particularly preferred. Within this range, the dispersing effect appears remarkably, and the coagulation effect is not recognized, so that a very small amount of the additive exhibits excellent characteristics. Furthermore, the amount of the organic amine salt of the water-soluble polymer to be added is within an optimum amount depending on the introduction ratio of the sulfonic acid group-containing monomer, the difference in the molecular weight and the type of the structure, and within the range where the effect can be sufficiently exhibited. Although not limited, since latex stability at the time of pH adjustment in the finishing step can be sufficiently imparted, and properties such as hue and tackiness are excellent, 0.1 to 100 parts by weight of monomer is used.
The amount is preferably 1 to 2 parts by weight, particularly preferably 0.2 to 1 part by weight.

The method of adding the organic amine salt of a water-soluble polymer having a sulfonic acid group introduced by addition polymerization and / or a polymer reaction after addition polymerization according to the present invention is carried out by the method of using an alkali metal of disproportionated rosin acid during emulsion polymerization. The salt may be added at the same time or may be added to the latex after the emulsion polymerization, and the object of the present invention can be sufficiently achieved. It is more preferable to add simultaneously with the alkali metal salt of disproportionated rosin acid, since the generation of precipitates during emulsion polymerization can be further suppressed.

Further, other emulsifiers and dispersants may be added as long as the object of the present invention can be maintained. For example, anionic emulsifiers, dispersants, nonionic emulsifiers, dispersants, and the like, sulfonic acid type surfactants such as alkali metal salts of alkyl sulfonic acids and alkali metal salts of alkyl allyl sulfonic acids, and alkali metal salts of alkyl sulfates Sulfates such as salts, sulfated surfactants such as polyethylene glycol ether sulfate alkali metal salts, condensates of sodium naphthalenesulfonate and formaldehyde, bisphenolsulfonic acid condensates, and sulfonic acid containing condensates of melaminesulfonic acid and formaldehyde Polycondensates,
Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol, sorbitan fatty acid ester,
Nonionic surfactants such as polyoxyethylene acyl ester can be exemplified.

In the emulsion polymerization of the present invention, water, a monomer, an emulsifier, a dispersant, a polymerization initiator, a molecular weight regulator and the like may be emulsified according to a known method, and polymerization may be carried out at a predetermined temperature.
Each raw material may be added all at once, sequentially added, or dividedly added. The polymerization conversion rate is preferably 50 to 80%, which is excellent in productivity such as easy recovery of the monomer and maintenance of an appropriate viscosity, and can be controlled to a predetermined conversion rate by adding a polymerization terminator. As the polymerization initiator used at the time of polymerization, known free radical-generating substances, for example, potassium persulfate, peroxides such as ammonium persulfate, hydrogen peroxide, inorganic or organic peroxides such as t-butyl hydroperoxide, 2,
2′-azobis- (2-amidinopropane) hydrochloride,
An azo compound such as 2,2′-azobis- (N, N′-dimethyleneisobutylamidine) hydrochloride is exemplified. These can be used alone or in a redox system in combination with a reducing substance such as thiosulfate and thiosulfite. The polymerization temperature can be in the range of 0 to 80 ° C. As the polymerization terminator, terminators usually used in radical polymerization, for example, phenothiazine, 2,6-t-butyl-4-methylphenol, hydroxyamine, 2,2
2'-methylene-bis- (4-ethyl-6-t-butylphenol) and the like can be used. As the molecular weight regulator,
The addition of a chain transfer agent is effective, and examples thereof include alkyl mercaptan, halogenated hydrocarbon, alkyl xanthogen disulfide, and sulfur.

Unreacted monomers and other organic compounds can be removed, for example, by steam flashing, ie, steam distillation at a temperature of 50 ° C. and an absolute pressure of 100 Torr. Thereafter, the latex is freeze-coagulated by, for example, a rotary cooling drum after adjusting the pH or the like, washed, and then mechanically compressed to form a film. The film is
For example, chloroprene rubber can be obtained by performing finishing treatment by hot air drying in a belt dryer.

The chloroprene rubber obtained in the present invention can be used as a base material for ordinary solution-grafted polychloroprene adhesives, one-part adhesives and two-part adhesives. The chloroprene rubber-based solution-grafted polychloroprene adhesive obtained in the present invention has excellent hue and tackiness. The solution-grafted polychloroprene adhesive having an excellent hue in the present invention is one in which the adhesive solution after grafting has an absorbance at 440 nm of 0.2 to 0.4. As a method for producing the solution-grafted polychloroprene adhesive, a known method of grafting an acrylate such as methyl methacrylate in a chloroprene rubber solution is used.

Examples of the organic solvent used for the solution grafting reaction include aromatic hydrocarbons and ketones, and these can be used alone or in combination.
As the aromatic hydrocarbon, for example, benzene, toluene,
Examples of ketones such as xylene include methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone and the like. Various radical initiators such as azobisisobutyronitrile, lauroyl peroxide, and benzoyl peroxide can be used as the solution grafting reaction initiator. Reaction temperature is 60 to 120
Performed in the range of ° C. Termination of the graft reaction can be performed by adding a reaction terminator. As the terminator, for example, 2,6-di-t-butyl-4-methylphenol,
2,6-di-t-butyl-4-phenylphenol,
2,2′-methylenebis (4-ethyl-6-t-butylphenol), 2,2′-methylenebis (4-methyl-
A phenolic compound such as 6-t-butylphenol) can be used.

Further, the chloroprene rubber obtained by the present invention is used as a base material, and a metal oxide such as zinc white or magnesia, a modified phenol resin, an organic solvent and various additives are added to the chloroprene rubber according to a conventional method. , A one-component adhesive excellent in tackiness, tackiness and adhesion can be obtained. As the hue value at that time, for example, the absorbance at 440 nm of a solution obtained by dissolving chloroprene rubber in toluene at a concentration of 5% is 0.03 to 0.2.

Further, a two-component adhesive comprising a rubber solution based on chloroprene rubber and a polyisocyanate obtained according to the present invention is also used as an adhesive having excellent hue, tackiness, tackiness and adhesion. Become. The polyisocyanate may be any polyisocyanate having an average number of functional groups of 2 or more. For example, tolylene diisocyanate (hereinafter referred to as T
DI), 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,5-naphthylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, tris (4-phenylisocyanate) thiophosphate, TDI dimer , TDI trimer and the like. The amount of addition is 0.1 to 0.1 parts by weight based on the active ingredient of polyisocyanate per 100 parts by weight of a chloroprene rubber adhesive solution containing chloroprene rubber and / or other adhesive components.
It can be added in the range of 5 parts by weight.

In the adhesive obtained from the chloroprene rubber of the present invention, various additives such as phenolic resin, rosin, coumarone resin, metal oxide, antioxidant, Agents and the like can be added.

[0028]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

In the examples, the hue of the obtained chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet resistance of the hue, and the hue and tackiness of the adhesive were measured and evaluated by the following methods. .

(A) Evaluation method of hue of chloroprene rubber In order to evaluate the hue of the obtained chloroprene rubber,
Chloroprene rubber is Shindo S from Shindo Metal Industry Co., Ltd.
100 ° C × 120kg / cm ² × using F type hydraulic press
Formed into a 2 mm thick sheet in 5 minutes,
Cool in 5 minutes. The prepared sample sheet was measured for color using a Lab method (reflection method) using a 607 color analyzer manufactured by Hitachi, Ltd., and the hue was evaluated based on the b value. The b value indicates the degree of yellow on the (+) side, the degree of blue on the (−) side, and becomes lighter as it approaches zero on the (+) side.

(B) Method of evaluating hue of chloroprene rubber solution Chloroprene rubber is dissolved in toluene to a concentration of 5%, and absorbance at a wavelength of 440 nm is measured using a U-1000 spectrophotometer manufactured by Hitachi, Ltd. Was evaluated for hue (yellowness). The smaller the value, the lighter the color.

(C) Evaluation method of heat aging resistance of hue The heat aging resistance of chloroprene rubber was measured by heating the chloroprene rubber in a gear oven at 70 ° C. for 3 days, and then applying the methods of (a) and (b). Hue was evaluated.

(D) Evaluation method of hue resistance of chloroprene rubber The hue resistance of chloroprene rubber was determined by visually observing the hue of the chloroprene rubber surface after irradiating chloroprene rubber with 254 nm ultraviolet rays at 20 ° C. for 4 or 10 hours. evaluated. The evaluation was indicated by ；: pale yellow, Δ: tan, ×: dark tan. (E) Evaluation method of hue of adhesive The hue of the solution-grafted polychloroprene adhesive was measured by evaluating the hue of the adhesive solution after grafting by the method of (b).

(F) Method of evaluating the tackiness of chloroprene rubber Chloroprene rubber was dissolved in toluene to a concentration of 15%, applied on an EVA (ethylene / vinyl acetate copolymer) foam, left at room temperature, and then left at room temperature. The quality of tackiness was judged based on the length of the standing time during which the pieces could be bonded to each other.
The evaluation was as follows: ；: very good (adhesive after standing for more than 60 min.), Δ: normal, ×: poor (adhesive not possible after standing for 10 min.).

Example 1 Chloroprene, n-dodecylmercaptan, disproportionated potassium rosinate, and diisopropylamine polystyrenesulfonate (weight average molecular weight of 5,0
00), sodium hydrosulfite, sodium hydroxide and water were charged into a 10-liter autoclave equipped with a stirrer, and stirring was started under a nitrogen atmosphere. An aqueous solution of potassium persulfate having a concentration of 0.35% was continuously dropped at 12 ° C. to initiate polymerization. As a polymerization terminator with a polymerization conversion rate of 70%,
The polymerization was terminated by adding 0.05 parts by weight of 2,2′-methylenebis- (4-ethyl-6-t-butylphenol). No precipitate was observed in the latex.

[0036]

[Table 1]

After the remaining unreacted monomers were removed by a steam flash method, the pH of the polymerized latex was adjusted to 6 with dilute acetic acid, freeze-coagulated, washed with water, and dried with hot air to finish chloroprene rubber. No abnormality was recognized in the finishing process.

The solution-grafted polychloroprene adhesive was composed of 100 parts by weight of chloroprene rubber, 460 parts by weight of toluene, 115 parts by weight of methyl ethyl ketone, 90 parts by weight of methyl methacrylate, and 0.5 part by weight of benzoyl peroxide. The grafting reaction was carried out to prepare the product. The reaction was started by increasing the temperature to 90 ° C. and then adding benzoyl peroxide. After performing the reaction for about 6 hours, 2 parts by weight of 2,6-t-butyl-4-methylphenol was added to stop the reaction. The conversion of methyl methacrylate was about 35%.

Hue of chloroprene rubber, hue of chloroprene rubber solution, heat aging resistance of hue, ultraviolet light resistance of hue,
Table 2 shows the evaluation results of the hue of the adhesive and the tackiness of the chloroprene rubber. As is clear from the table, the result was a light hue, a small change in hue, and good tackiness.

[0040]

[Table 2]

Example 2 The amount of diisopropylamine polystyrenesulfonate (weight average molecular weight 5,000) was increased from 0.3 part by weight to 0.1 part by weight.
Polymerization was carried out in the same manner as in Example 1 except that the amount was changed to 6 parts by weight. The composition ratio of each raw material is shown in Table 1. No precipitates in the latex and no abnormalities in the finishing step were observed.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet light resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are lighter hues. , The change in hue is small,
The result was that tackiness was good.

Example 3 Polymerization was carried out in the same manner as in Example 1 except that the method of adding diisopropylamine polystyrene sulfonate (weight average molecular weight: 5,000) was changed from the initial stage to that after addition of a polymerization terminator. . The composition ratio of each raw material is shown in Table 1. Precipitates in the latex were slightly observed on the stirrer, but no abnormality was found in the finishing step.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet light resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are expressed in pale hue. , The change in hue is small,
The result was that tackiness was good.

Example 4 The addition of 0.3 parts by weight of diisopropylamine polystyrenesulfonate (weight average molecular weight 5,000) was carried out in the presence of triethylamine polystyrenesulfonate (weight average molecular weight 7.0, 0).
00) Polymerization was carried out in the same manner as in Example 1 except that the amount was changed to 1.5 parts by weight. The composition ratio of each raw material is shown in Table 1. No precipitate was found in the latex. In the finishing step, a slight outflow of rubber was observed during washing with water, but the chloroprene rubber was sufficiently finished.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet light resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are light hue. , The change in hue is small,
The result was that tackiness was good.

Example 5 Diisopropylamine polystyrene sulfonate (weight average molecular weight: 5,000) was added in an amount of 0.3 part by weight to diisobutylamine polystyrene sulfonate (weight average molecular weight: 7,7).
000) Polymerization was carried out in the same manner as in Example 1 except that the amount was changed to 0.1 part by weight. The composition ratio of each raw material is shown in Table 1. No precipitate was found in the latex. In the finishing step, a slight outflow of rubber was observed during washing with water, but the chloroprene rubber was sufficiently finished.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the UV resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are lighter hues. , The change in hue is small,
The result was that tackiness was good.

Example 6 Polymerization was carried out in the same manner as in Example 1 except that the amount of disproportionated potassium rosinate was changed from 4 parts by weight to 2 parts by weight. The composition ratio of each raw material is shown in Table 1. Precipitates in the latex were slightly observed on the stirrer, but no abnormality was found in the finishing step.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet light resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are light hue. , The change in hue is small,
The result was that tackiness was good.

Example 7 Polymerization was carried out in the same manner as in Example 1 except that the amount of disproportionated potassium rosinate was changed from 4 parts by weight to 6 parts by weight. The composition ratio of each raw material is shown in Table 1. No precipitates in the latex and no abnormalities in the finishing step were observed.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet light resistance of the hue, and the hue of the adhesive were 4 parts by weight of disproportionated potassium rosinate. Compared with the added amount, the result was that the hue to be yellowed and the change in hue were large, but within the usable range.

Example 8 Diisopropylamine polystyrenesulfonate was added to diisobutylamine poly-2-acrylamido-2-methylpropanesulfonate (weight average molecular weight 10,000
0) Polymerization was carried out in the same manner as in Example 1 except that the addition was changed to 0.5 parts by weight. The composition ratio of each raw material is shown in Table 1. No precipitate was found in the latex. In the finishing step, a slight precipitation of rubber was observed when the pH was adjusted to 6 with dilute acetic acid, but the chloroprene rubber was sufficiently finished.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the UV resistance of the hue, the hue of the adhesive, and the tackiness of the chloroprene rubber are lighter hues. , The change in hue is small,
The result was that tackiness was good.

Comparative Example 1 Example 1 was repeated except that the addition of diisopropylamine polystyrenesulfonate was changed to 0.7 parts by weight of a condensate of sodium naphthalenesulfonate and formaldehyde (Demol N, manufactured by Kao Corporation). Polymerization was performed in the same manner. The composition ratio of each raw material is shown in Table 1. No precipitates in the latex and no abnormalities in the finishing step were observed.

As shown in Table 2, the tackiness of the chloroprene rubber was good, but the hue of the chloroprene rubber was
The hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet resistance of the hue, and the hue of the adhesive were inferior in terms of yellowness and change in hue.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that the addition of diisopropylamine polystyrenesulfonate was changed to the addition of 0.5 parts by weight of sodium dodecylbenzenesulfonate. The composition ratio of each raw material is shown in Table 1. No precipitates in the latex and no abnormalities in the finishing step were observed.

As shown in Table 2, the hue of the chloroprene rubber, the hue of the chloroprene rubber solution, the heat aging resistance of the hue, the ultraviolet resistance of the hue, and the hue of the adhesive are a light hue and a small change in hue. Was the result. However, the tackiness of chloroprene rubber was very poor.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the addition of diisopropylamine polystyrenesulfonate was changed to the addition of 0.5 part by weight of diisopropylamine polymethacrylate (weight average molecular weight: 5,000). Was. The composition ratio of each raw material is shown in Table 1. No precipitate was found in the latex, but in the finishing step, p
When H was adjusted to 6, the precipitation of rubber was very large, and the chloroprene rubber could not be finished.

[0060]

The chloroprene rubber produced by the production method of the present invention has excellent light-colored hues, heat aging resistance and ultraviolet light resistance, which are not available in conventional chloroprene rubber, and is coated with an adhesive when used as an adhesive. Since it has the tackiness that can maintain the tackiness for a long time later, it is suitable as an adhesive for various uses such as wood, leather, cloth, rubber, plastic, and metal.

[0061]

Claims (5)

[Claims] 1. An aqueous radical emulsion polymerization of chloroprene or a mixture of chloroprene and a monomer copolymerizable therewith, together with an alkali metal salt of disproportionated rosin acid,
A process for producing chloroprene rubber, comprising using, as a dispersant, an organic amine salt of a water-soluble polymer containing a sulfonic acid group introduced by addition polymerization and / or a polymer reaction after addition polymerization. 2. The process for producing chloroprene rubber according to claim 1, wherein the organic amine used for the organic amine salt of the water-soluble polymer containing a sulfonic acid group is hardly soluble or insoluble in water. 3. The method for producing chloroprene rubber according to claim 1, wherein the organic amine salt of the water-soluble polymer having a sulfonic acid group is a polymer having a styrenesulfonic acid structure. 4. The organic amine salt of a water-soluble polymer containing a sulfonic acid group having a weight average molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁴ . A method for producing the chloroprene rubber described above. 5. An organic polymer of a water-soluble polymer containing 2 to 6 parts by weight of a disproportionated rosin acid and 0.1 to 2 parts by weight of a sulfonic acid group per 100 parts by weight of all monomers. The method for producing chloroprene rubber according to any one of claims 1 to 3, wherein an amine salt is used.