JP3392181B2 - Method for producing chloroprene graft copolymer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a chloroprene graft copolymer used as an adhesive and having little coloration, and more specifically to polyvinyl chloride containing a large amount of a plasticizer (hereinafter referred to as "soft vinyl chloride"). (Abbreviation), a method for producing a chloroprene graft copolymer suitable as an adhesive for materials such as polyurethane and nylon.

[0002]

2. Description of the Related Art Conventionally, a chloroprene polymer is produced by polymerizing chloroprene alone or a mixture of chloroprene and a monomer copolymerizable with chloroprene in an alkaline aqueous emulsion.

At this time, as the emulsifier, anionic emulsifiers such as rosin acid salts, alkyl fatty acid salts and alkylbenzene sulfonates, nonionic emulsifiers such as alkyl polyethylene glycols and polyvinyl alcohols, and cationic emulsifiers such as quaternary ammonium salts are used. Etc. are used.

Among them, rosin acid salt is known to have a good film strength during freeze-coagulation and drying after completion of polymerization as compared with other emulsifiers and to prevent excessive shrinkage and breakage during drying. (Chemical Engineering Progress, 43
(8), 391 (1947).)

Therefore, in the production of chloroprene polymers, it is most common and preferred to use a rosin acid salt as an emulsifier.

Rosin acids are classified into types such as gum rosin, wood rosin, tall oil rosin, and disproportionated rosins obtained by disproportionating them, depending on the production method.
In the production of the chloroprene polymer, all rosin acids can be used, but when any rosin acid is used, the produced polymer is colored from yellow to brown.

Further, in the production of chloroprene polymer, if the polymerization rate is too high, a component insoluble in an organic solvent is produced and the physical properties of the obtained chloroprene polymer are impaired. Therefore, it is common to add a polymerization terminator to terminate the polymerization.

As the polymerization terminator for stopping the polymerization, for example, phenothiazine, tetraethylthiuram disulfide and the like are used, but the coloring component contained in these may also cause the formed polymer to be colored.

On the other hand, when it is used as an adhesive, especially as an adhesive such as soft vinyl chloride, a chloroprene polymer is used as a raw material and graft-reacted with methyl methacrylate in an organic solvent to form a graft copolymer.

[0010]

The graft copolymer for adhesives thus produced is generally colored due to the influence of the colored chloroprene polymer, and has the following problems. ing.

For example, when it is used for manufacturing shoes using soft PVC, it is mainly used for adhering the upper part of the shoe to the sole of the shoe. In the conventional chloroprene-based graft copolymer, the adhesive is colored. Therefore, the adhesive layer is conspicuous and the appearance of the product is deteriorated. Also, when it is used for purposes other than shoe manufacturing, the same thing as this occurs and the appearance of the product deteriorates. For these reasons, it has been desired to eliminate the coloring of the adhesive.

As a result of extensive studies aimed at solving the above problems, the present invention succeeded in producing a chloroprene graft copolymer with little coloring.

[0013]

That is, according to the present invention, chloroprene alone or a mixture of chloroprene and a monomer copolymerizable with chloroprene is used as Gardner color number 4
A chloroprene polymer obtained by polymerization in an alkaline aqueous emulsion in the presence of the following light-colored rosin acid and / or light-colored rosinate is used as a trunk polymer to graft-polymerize a (meth) acrylic acid ester. And a method for producing a chloroprene graft copolymer, wherein the use of a mixture of diethylhydroxylamine and a phenolic anti-aging agent as a polymerization terminator in the production of a chloroprene polymer that is a trunk polymer And a method for producing the chloroprene graft copolymer.

In the present invention, the coloration of the chloroprene-based graft copolymer is greatly improved only by using as a raw material a chloroprene polymer produced by using a lightened rosin acid / or a lightened rosin acid salt as an emulsifier. However, by using as a raw material a chloroprene polymer produced using a polymerization terminator containing diethylhydroxylamine as a polymerization terminator and a phenolic antioxidant as a component, a graft copolymer with less coloring is obtained. can get.

The monomer copolymerizable with chloroprene is not particularly limited and, 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, may be used in combination of two or more as necessary. I don't care.

The molecular weight modifier is not particularly limited as long as it is one generally used in the production of chloroprene polymers. For example, long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan,
Known chain transfer agents such as dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide, and iodoform can be used.

[0017] in your Keru emulsifier to the present invention is to use a light-colored rosin acid and / or light-colored rosin acid salt. Here pale rosin acid used, for example, those more handling normal rosin acids distillation or column chromatography coloring components were removed by was a Gardner color number of 4.0 or less. Further, the lightened rosin acid salt is a salt of lightened rosin acid,
Examples thereof include alkali metal salts, alkaline earth metal salts, ammonium salts and the like, and sodium salts and potassium salts are usually preferably used.

The amount of the light-colored rosin acid and / or the light-colored rosin acid used is the same as in the case of ordinary rosin acid,
Generally, it is preferable to use about 0.1 to 10 parts by weight in terms of rosin acid per 100 parts by weight of all monomers.

At this time, it is not preferable to use an ordinary rosin acid in combination because the resulting product is colored, but an emulsifier such as an emulsifier such as fatty acid or alkylbenzene sulfonic acid or a sodium salt of a condensate of naphthalene sulfonic acid and formaldehyde is stabilized. The combined use of agents is possible within a range that does not impair the effects of the present invention.

The polymerization method may be the same as in the case of producing a general chloroprene polymer, but the polymerization temperature is 0 to
It is desirable to carry out in the range of 55 ° C.

As the polymerization initiator, organic or inorganic peroxides used in the usual emulsion polymerization method of chloroprene, for example, benzoyl peroxide, potassium persulfate, ammonium persulfate and the like are used.

As the polymerization terminator in the present invention, a commonly used terminator such as phenothiazine, tetraethylthiuram disulfide and the like may be used, but in order to obtain a higher lightening effect, diethylhydroxylamine and a phenolic aging preventive agent are used. Preference is given to using a mixture of agents.

Examples of the phenol anti-aging agent used in the present invention include 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-4-.
Ethylphenol, mono (α-methylbenzyl) phenol, di (α-methylbenzyl) phenol, tri (α
-Methylbenzyl) phenol, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol),
2,2'-methylenebis (4-methyl-6-tert-
Butylphenol), 4,4'-butylidene bis (3-
Methyl-6-tert-butylphenol), 4,4 '
-Thiobis (3-methyl-6-tert-butylphenol), 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone and the like can be used.

In the present invention, a chloroprene polymer produced in this way with little coloring is used as a raw material to obtain a graft copolymer for adhesives with little coloring. The method for producing the graft copolymer may be the same as the usual method except that the less colored chloroprene polymer is used as a raw material, and the less colored chloroprene polymer and (meth) acrylic acid ester are dissolved in an organic solvent to perform polymerization. Add an initiator, heat to cause graft reaction,
The viscosity of the polymerization solution is measured, and when it reaches a predetermined viscosity, it is cooled to stop the polymerization.

Examples of the (meth) acrylic acid ester used in the present invention include methyl (meth) acrylate and (meth) acrylate.
Examples thereof include ethyl acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. These (meth) acrylic acid esters may be used alone or in combination of two or more depending on the purpose.

In the preparation of the above graft copolymer for adhesives, it is preferable to use 30 to 120 parts by weight of (meth) acrylic acid ester, more preferably 50 to 100 parts by weight, based on 100 parts by weight of the chloroprene polymer. Good to use. If the amount is less than 30 parts by weight, the adhesive strength to the material will be insufficient, and if the amount is more than 120 parts by weight, the viscosity of the reaction solution in the graft reaction will increase sharply and the control of polymerization will be difficult.

As the organic solvent used in this graft reaction, aromatic hydrocarbons such as benzene, toluene and xylene, methyl ethyl ketone, methyl isopropyl ketone,
Use ketones such as methyl isobutyl ketone and esters such as ethyl acetate and butyl acetate, either alone or as a mixed solution.

As the polymerization initiator, various radical initiators such as azobisisobutyronitrile, lauroyl peroxide, benzoyl peroxide and the like can be used, and among them, benzoyl peroxide is preferably used. The amount of the initiator used is 10 for the grafted monomer.
0.1 parts by weight or more is used with respect to 0 parts by weight. Also, a suitable chain transfer agent can be used to control the molecular weight.

The reaction temperature needs to be higher than the decomposition temperature of the initiator used, and is usually 60 to 100 ° C.
Further, good storage stability can be obtained by adding quinones having a stabilizing effect on the polymerization solution at the end of the polymerization.

The chloroprene graft copolymer thus obtained may be used as it is as an adhesive, but a pressure-sensitive adhesive, a stabilizer, a commonly used adhesive, depending on the purpose of use.
Other elastomers may be added.

[0031]

The present invention will be described in more detail with reference to the following examples.

Production Example 1 Using a reactor having an internal volume of 10 liters, 4000 g of chloroprene monomer and 10 g of n-dodecyl mercaptan were distilled together with ordinary rosin acid to remove low boiling components and high boiling components as coloring components. 120 g of a lightened rosin acid having a Gardner color number of 3 and 3 g of sodium hydroxide and 48
The emulsion was emulsified with 00 g of distilled water, and potassium persulfate was used as an initiator to carry out polymerization at 10 ° C. in a nitrogen atmosphere. When the rate of polymerization reached 70%, an emulsion of phenothiazine was added to stop the polymerization, and unreacted monomers were removed by the conventional steam stripping method, and the latex obtained was freeze-dried by the conventional method. By the method, chips of chloroprene polymer were obtained. Then, it was color inspected for chips of the chloroprene polymer by Nippon Denshoku Industries Co., Ltd. Z- sigma 80 calorimetric color difference meter.

Production Example 2 Diethylhydroxylamine as a polymerization terminator and 4,
Polymerization was performed in the same manner as in Production Example 1 except that a mixture of 4'-thiobis (3-methyl-6-tert-butylphenol) was used, and a chip of a chloroprene polymer was prepared, and a color tone inspection was performed.

Example 1 Using a reactor having an internal volume of 1 liter, 100 g of chips of the chloroprene polymer obtained in Production Example 1 was dissolved in 600 g of toluene, 50 g of methyl methacrylate was added, and benzoyl peroxide was used as an initiator. Graft polymerization was carried out at 85 ° C. for 5 hours to obtain a chloroprene graft copolymer. Then, this chloroprene graft copolymer was subjected to color tone inspection by a Z-80 colorimetric color difference meter manufactured by Nippon Denshoku Industries Co., Ltd.

Example 2 Using the chips of the chloroprene polymer obtained in Production Example 2, a chloroprene graft copolymer was prepared in the same manner as in Example 1 and the color tone was examined.

Production Comparative Example 1 Polymerization was carried out in the same manner as in Production Example 1 except that disproportionated rosin acid having a Gardner color number of 10 (Londis R, manufactured by Arakawa Chemical Co., Ltd.) was used as an emulsifier, to obtain a chloroprene polymer, and tones An inspection was done.

Comparative Example 1 Using the chips of the chloroprene polymer obtained in Production Comparative Example 1, a chloroprene graft copolymer was prepared in the same manner as in Example 1 and the color tone was examined.

The results of the color tone inspection of the rubber chips synthesized in Production Examples 1 and 2 and Production Comparative Example 1 are shown in Table 1, and the results of the color tone inspection of the chloroprene graft copolymers prepared in Examples 1 and 2 and Comparative Example 1 are shown. Is shown in Table 2.

[0039]

[Table 1] 1) N: Yellowness. The larger this value, the stronger the yellow color. WB: Whiteness. The larger this number, the less coloring

[0040]

[Table 2] 1) N: Yellowness. The larger this value, the stronger the yellow color. WB: Whiteness. The larger this number, the less coloring

[0041]

INDUSTRIAL APPLICABILITY As described above, the present invention is an excellent method for producing a chloroprene graft copolymer which is less colored and is suitable as an adhesive.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-1-284544 (JP, A) JP-A-56-76415 (JP, A) JP-B-49-37118 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) C08F 279/02

Claims (3)

(57) [Claims] 1. A chloroprene alone or a mixture of chloroprene and a monomer copolymerizable with chloroprene,
Distilling or column chromatography of rosin acid
A chloroprene polymer obtained by polymerization in an alkaline aqueous emulsion in the presence of a lightened rosin acid and / or a lightened rosin acid salt having a Gardner color number of 4 or less, which has been treated to remove coloring components, as a trunk polymer, A method for producing a chloroprene graft copolymer, which comprises graft-polymerizing a (meth) acrylic acid ester. 2. A method characterized by performing graft polymerization in an organic solvent.
The chloroprene graft copolymer according to claim 1, wherein
Manufacturing method. In the production of chloroprene polymer is wherein the trunk polymer, according to claim 1 or 2 chloroprene graft copolymerization according to, characterized by using a mixture of diethylhydroxylamine and a phenolic antioxidant as the terminating agent Manufacturing method of coalescence.