JP2003055409A - Method for manufacturing chloroprene polymer and composition thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for manufacturing a chloroprene polymer that controls the latex particle size, and enhances the polymerization rate so that the method is stable and gives excellent productivity. SOLUTION: A chloroprene polymer with a small latex particle size is manufactured at a high polymerization velocity, by radically polymerizing a monomer mixture comprising 2-chloro-1,3-butadiene in the presence of >=0.1 and <10 parts by mass of an alcohol per 100 parts by mass of the total monomers. It is particularly preferable that the alcohol is substantially insoluble in water, having a solubility in water at 20 deg.C of <=1 g/100 g. It is further preferable that the alcohol is a saturated monohydric alcohol represented by the following formula (1) that can further enhance the polymerization rate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a chloroprene polymer, and more particularly to a technique for controlling the polymerization rate, controlling the latex particle size, and stabilizing the latex.

[0002]

2. Description of the Related Art Conventionally, in radical polymerization of monomers other than 2-chloro-1,3-butadiene, such as styrene, acrylic acid esters, methacrylic acid esters, etc., control of latex particle size and improvement of polymerization rate. For the above purpose, many techniques for adding alcohols have been studied and reported. `` Journal of Polymer Science: P
art A: Polymer Chemistry, Vol.39, No.6,2001, page.
898-912 ”, using sodium persulfate as an initiator and sodium dodecylbenzenesulfonate as an emulsifier, the radical of styrene was obtained in the presence of three kinds of alcohols (1-butanol, 1-pentanol, 1-hexanol). It reports on emulsion polymerization. "Polymeric Mat
erials Science and Engineering, Vol.80, 1999, pag
e.554-555 ”, ammonium persulfate-N, N, N'N'-tetramethylethylenediamine as a redox-based initiator and sodium dodecylbenzenesulfonate as an emulsifier were used to prepare acrylic acid in the presence of 1-pentanol. Butyl, ethyl acrylate, butyl methacrylate,
We have reported on the radical emulsion polymerization of ethyl methacrylate, methyl methacrylate and styrene. "Journal of
Applied Polymer Science, Vol.68, No.12, 1998, pag
e.2029-2039 ", ammonium persulfate-sodium bisulfite is used as a redox initiator and sodium dodecylbenzenesulfonate is used as an emulsifier in the presence of cetyl alcohol (that is, 1-hexadecanol), butyl acrylate, styrene. Has reported on the radical emulsion polymerization of. `` Polymer, Vol.37, No.12, 1996, page.
2509-2516 ", for radical emulsion polymerization of styrene in the presence of cetyl alcohol (ie 1-hexadecanol) using cumene hydroperoxide-ferrous sulfate as a redox initiator and sodium lauryl sulfate as an emulsifier. Reporting.

In radical polymerization of 2-chloro-1,3-butadiene, no examples have been found in which alcohols are used for the purpose of controlling the latex particle size and improving the polymerization rate.
Regarding the addition of alcohols during radical polymerization of 2-chloro-1,3-butadiene, JP-A-6-145426.
In the publication (Applicant: Road Corporation), a technique of suspending or emulsion-polymerizing a butadiene-based monomer in the presence of polyvinyl alcohol and alcohols that are miscible with water as a stabilizing solvent is proposed. There is. The technique described in this publication is aimed at improving the film forming characteristics of the latex and the adhesive, and does not lead to the control of the latex particle size and / or the polymerization rate, which is the subject of the present invention. Further, in this publication, the suitable addition amount of the alcohols is 10 to 100 parts by mass with respect to 100 parts by mass of the monomer, but this is too large, and reduction of the volatile organic solvent is required. At present, it is a problematic technology.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel method for polymerizing a chloroprene polymer which has a controlled latex particle size, an increased polymerization rate, and is stable and excellent in productivity.

[0005]

As a result of repeated studies to achieve the above object, the present inventors have found that 2-chloro-1,3-
With respect to 100 parts by mass of the total amount of monomers including butadiene,
By radical polymerization of a monomer mixture containing 2-chloro-1,3-butadiene in the presence of 0.1 parts by mass or more and less than 10 parts by mass of alcohols, the latex particle size is small and the polymerization rate is high. , Invented a method for producing a chloroprene polymer.

The details of the present invention will be described below. The monomer in the present invention is 2-chloro-1,3-butadiene alone or a plurality of monomer mixtures containing 2-chloro-1,3-butadiene as an essential monomer. Examples of the monomer copolymerizable with 2-chloro-1,3-butadiene include 2,3-dichloro-1,3-butadiene,
1-chloro-1,3-butadiene, 1,3-butadiene, 2-methyl-1,3-butadiene (ie isoprene), styrene, acrylonitrile, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, etc. Is mentioned. Then, two or more kinds of these may be copolymerized.

The chloroprene polymers of the present invention also include sulfur modified chloroprene polymers. By adding 0.2 to 2 parts by mass of sulfur to 100 parts by mass of a total of monomers including 2-chloro-1,3-butadiene and starting a radical polymerization reaction, tensile strength and bending fatigue resistance are obtained. It is possible to obtain a sulfur-modified chloroprene polymer having excellent properties, abrasion resistance, and dynamic characteristics. Originally, it is known that sulfur itself has a function of delaying the polymerization rate, and the polymerization rate of a system containing sulfur becomes slower than that of a system containing no sulfur. INDUSTRIAL APPLICABILITY The present invention is particularly effective in a reaction system in which sulfur is present, and can efficiently increase the polymerization rate.

The emulsifier and / or dispersant used in the emulsion polymerization of the present invention is not particularly limited, and various anionic, nonionic and cationic emulsifiers usually used in emulsion polymerization can be used. Examples of anionic emulsifiers include carboxylic acid type and sulfuric acid ester type.
Rosin acid and alkali metal salts of rosin acid having 8 to 8 carbon atoms
Examples include 20 alkyl sulfonates, alkyl aryl sulphates, condensates of sodium naphthalene sulfonate and formaldehyde, and the like. Specific examples of the nonionic type include polyvinyl alcohol, polyvinyl ether or a copolymer thereof (for example, a copolymer with maleic acid), polyvinylpyrrolidone or a copolymer thereof (for example, a copolymer with vinyl acetate), or Examples thereof include those obtained by chemically modifying these (co) polymers, cellulose derivatives (hydroxyethyl cellulose), and the like. Here, the saponification degree of polyvinyl alcohol,
The degree of polymerization is not particularly limited, but the degree of saponification is 60.
˜95 mol% and a degree of polymerization of 200 to 700 are preferred. The polyvinyl alcohol referred to herein may be of a modified type (for example, a copolymer with acrylamide, an acetoacetylated type, a type having a polyethylene unit (usually called RS type)). . 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 emulsifier used in the present invention is most preferably an alkali metal salt of rosin acid which is excellent in stability of the emulsified state during polymerization. Here, the rosin acids are volatile resin of pine resin (commonly known as rosin), and specifically, abietic acid, neoabietic acid, parastoric acid, levopimaric acid, dehydroabietic acid, pimaric acid,
It is a mixture of tricyclic resin acids such as isopimaric acid, sandaracopimaric acid, comonic acid, anticopalic acid, lambertian acid, dihydroagato acid and acetylisocupresic acid. The composition ratio of these tricyclic resin acids varies depending on the raw material (raw wood), the place of origin, the processing method, etc., and is not particularly limited. Particularly, those having abietic acid content of 30% by mass or more are preferred because they are industrially easily available.

The addition amount of the emulsifier and / or dispersant in the present invention is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total amount of the initially charged monomers. If it is less than 0.2 parts by mass, the emulsifying power is not sufficient, and if it exceeds 10 parts by mass, the physical properties of the rubber finished from the latex may be adversely affected.

The alcohols in the present invention are those in which a hydrogen atom of a chain or alicyclic hydrocarbon is replaced with a hydroxyl group. The number of hydroxyl groups in the molecule and the position of the hydroxyl group in the molecule are not limited. Further, it may be a lower alcohol (having 5 or less carbon atoms), a higher alcohol (having 6 or more carbon atoms), or may have an unsaturated bond in the molecule.

In particular, the alcohol is preferably a substantially water-insoluble alcohol having a solubility in water at 20 ° C. of 1 g / 100 g or less, and further, a saturated monohydric alcohol represented by the following formula (2). This is preferable because the polymerization rate can be further increased.

[0013]

[Chemical 2]

The alcohols represented by the above formula (2) are specifically 1-propanol (n = 3), 2-propanol (n = 3), 1-butanol (n = 4), 1
-Pentanol (n = 5), 1-hexanol (n =
6), 1-heptanol (n = 7), 2-heptanol (n = 7), 3-heptanol (n = 7), 4-heptanol (n = 7), 1-octanol (n = 8), 2-
Octanol (n = 8), 1-nonanol (n = 9),
2-nonanol (n = 9), 1-decanol (n = 1)
0), 1-undecanol (n = 11), 1-dodecanol (ie lauryl alcohol, n = 12), 1-hexadecanol (ie cetyl alcohol, n = 16), stearyl alcohol (n = 18) and the like. To be

The amount of alcohol added is 2-chloro-
The amount is 0.1 part by mass or more and less than 10 parts by mass with respect to 100 parts by mass in total of the monomers containing 1,3-butadiene. Within this range, the best effect on the polymerization rate can be obtained.

Charge conditions such as pH of the emulsion, charge amount of water, charge method of monomer and the like, which are necessary for stably and safely proceeding the emulsion polymerization, are not particularly limited. It may be appropriately selected depending on the type of the monomer and / or the emulsifier.

The amount of water is 80 to 250 parts by mass, preferably 90 to 1 part by mass, based on 100 parts by mass of the total amount of the monomers.
It is 50 parts by mass. If it is less than 80 parts by mass, the latex particles tend to aggregate. Further, when it exceeds 250 parts by mass, the solid content of the latex becomes low, and as a result, the latex is concentrated, or the polymer in the latex is solidified (sheets, pellets, chips, etc.) by a process such as freezing or drying. Productivity deteriorates.

As the polymerization initiator, potassium persulfate, benzoyl peroxide, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide and the like which are commonly used in radical polymerization are used. It may also be a redox initiator combined with a reducing agent.

The type of the chain transfer agent for the chloroprene polymer in the present invention is not particularly limited, and is usually 2-
Although those used for emulsion polymerization of chloro-1,3-butadiene can be used, for example, long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, and dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide. Known chain transfer agents such as bisphenols and iodoform can be used.

From the practical point of view, the conversion is 50 to 1 in terms of conversion.
It is carried out in the range of 00%, and then a polymerization inhibitor is added to stop it. As the polymerization inhibitor (polymerization inhibitor) for the polymer, for example, 2,6-tert-butyl-4-methylphenol, phenothiazine, hydroxylamine and the like can be used. The polymerization temperature is 0 to 10 for stable polymerization.
0 degreeC is preferable, More preferably, it is 0-55 degreeC.

The latex average particle size in the present invention is
D50% particle diameter measured by laser diffraction scattering method (also called laser diffraction method) (cumulative particle distribution based on volume is 50%
(Particle size = medium size or median size)
Is preferably 20 nm or more and less than 150 nm. When the average particle size is less than 20 nm or 150 nm or more, the emulsion stability of the latex may be deteriorated. In order to further increase the polymerization rate, the maximum diameter of the latex is preferably 50 nm or more and less than 300 nm. When the maximum particle size is less than 50 nm or 300 nm or more, the emulsion stability of the latex may be deteriorated.

The laser diffraction / scattering method utilizes the fact that laser light is applied to particles dispersed in a dispersion medium and the intensity pattern of the diffracted / scattered light of the laser light depends on the size of the particles. Observe and Fraunforfa (Fr
It is a method of obtaining the particle size distribution by using the aunhofer diffraction theory or the Mie scattering theory. Commercially available measuring instruments include SALD-2000 (Shimadzu Corporation), LA-910W (Horiba Ltd.),
LA-920 (manufactured by Horiba, Ltd.), Coulter L
S (manufactured by Coulter Co., Ltd.), Coulter N4 plus type submicron particle analyzer (manufactured by Coulter Co., Ltd.), Microtrac UPA (manufactured by Nikkiso Co., Ltd.) and the like.

It should be noted that regardless of the amount of unreacted monomer contained in the sample latex at the time of measurement, any latex after the monomer is removed by heating under reduced pressure during the polymerization reaction, after the polymerization reaction is stopped, etc. But good.

The use of the chloroprene polymer produced in the present invention is not particularly limited. This is the same as the use of the conventional chloroprene polymer. The chloroprene polymer latex of the present invention, the polymer is isolated by freeze coagulation or salting out,
It can be solidified by washing with water and drying. This can be processed into various agricultural and industrial materials by known vulcanization, foaming (closed cells, open cells) and molding technology, and by dissolving it in an appropriate organic solvent, solvent-based adhesives, solvent-based paints, solvent-based paints It can be used as a binder. Also, for example,
By adding tackifying resin, plasticizer, thickener, curing agent (vulcanizing agent), vulcanization accelerator, etc. to the latex of chloroprene polymer as necessary, water-based adhesive, resorcinol formaldehyde latex adhesive Agent (RFL adhesive), water-based paint, matting agent, coating agent (coating agent), surface treatment agent, waterproofing agent for coating film, and binder for molding powder products such as rubber chips and sand and various crushed powders ( Binder), treatment agent (binder) for fibers and cloths for carpet processing, dipping products such as gloves and contraceptives, waterproof treatment agent for footwear, sediment outflow prevention (sediment scattering prevention) latex, seeds and fertilizers on the ground and mats It can be used as a vegetation latex for fixing soil, a concrete modifier, an asphalt modifier, and the like.

[0025]

The present invention will be described below with reference to examples, but these examples do not limit the present invention.

[Example 1] To 130 parts by mass of distilled water, 3.5 parts by mass of sodium rosinate (manufactured by Harima Kasei Co., Ltd.), 0.3 parts by mass of sodium hydroxide, sodium naphthalenesulfonate and formaldehyde were combined. The condensate is 1.
0 mass part was melt | dissolved at 40 degreeC, and the rosin acid salt aqueous solution was produced. 0.5 parts by mass of sulfur and 2 parts by mass of cetyl alcohol (1-hexadecanol) were dissolved in 100 parts by mass of 2-chloro-1,3-butadiene to prepare a monomer solution. An aqueous rosinate solution and a monomer solution were charged into a reactor having an internal volume of 5 liters, and the mixture was stirred in a nitrogen atmosphere at 35 ° C. for 10 minutes for emulsification. Then, the temperature was raised to 40 ° C. over 30 minutes, and when the liquid temperature became stable at 40 ° C., a 2% by mass aqueous solution of potassium persulfate was used as a polymerization initiator at a rate of 0.015 parts by mass (wet) per minute. Was added dropwise to start the polymerization reaction. When the conversion reached 70% by mass, an emulsion containing a chloroprene monomer, distilled water, thiodiphenylamine and diethylhydroxylamine was added to terminate the polymerization. The polymerization rate and the latex particle size were measured by the following methods.

[Calculation of Polymerization Rate] The specific gravity (ρ) was measured 0 hour, 0.5 hour, 1.0 hour and 1.5 hours after the start of dropping the polymerization initiator. Based on the data, the change in specific gravity per hour (Δρ / h
r) was calculated.

[Measurement of Particle Diameter] The latex immediately after the completion of the polymerization reaction was diluted with distilled water so that the solid content concentration was 0.05% by mass, and Microtrac UPA was used.
(Manufactured by Nikkiso Co., Ltd.), the average particle diameter and the maximum particle diameter were measured.

[Example 2] Polymerization was carried out in the same manner as in Example 1 except that 2 parts by mass of cetyl alcohol in Example 1 was replaced with 0.8 parts by mass of 1-hexanol.
The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 3] Polymerization was carried out in the same manner as in Example 1 except that 2 parts by mass of cetyl alcohol in Example 1 was replaced with 0.7 parts by mass of 1-pentanol.
The method of measuring the polymerization rate and the particle size is the same as in Example 1.

Example 4 Polymerization was carried out in the same manner as in Example 1 except that 2 parts by mass of cetyl alcohol in Example 1 was replaced with 0.5 parts by mass of 1-propanol.
The method of measuring the polymerization rate and the particle size are the same as in Example 1.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that alcohols were not added to the monomer solution. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

The evaluation results obtained in Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

[0034]

[Table 1]

[Example 5] To 130 parts by mass of distilled water, 3.5 parts by mass of sodium rosinate (manufactured by Harima Kasei Co., Ltd.), 0.3 part by mass of sodium hydroxide, sodium naphthalenesulfonate and formaldehyde were combined. The condensate is 1.
0 parts by mass, 0.5 parts by mass of sodium hydrogen sulfite at 40 ° C.
And dissolved to prepare an aqueous rosinate solution. 100 parts by mass of 2-chloro-1,3-butadiene, 0.15 parts by mass of n-dodecyl mercaptan and 2 parts by mass of cetyl alcohol (1-hexadecanol) were dissolved to prepare a monomer solution. An aqueous rosinate solution and a monomer solution were charged into a reactor having an internal volume of 5 liters, and the mixture was stirred in a nitrogen atmosphere at 10 ° C. for 10 minutes for emulsification. 2% by mass of potassium persulfate as a polymerization initiator at a liquid temperature of 10 ° C.
The aqueous solution was added dropwise at a rate of 0.015 parts by mass (wet) per minute to start the polymerization reaction. When the conversion reached 60% by mass, an emulsion containing a chloroprene monomer, distilled water, thiodiphenylamine and diethylhydroxylamine was added to terminate the polymerization. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 6] Polymerization was carried out in the same manner as in Example 5, except that 2 parts by mass of cetyl alcohol in Example 5 was replaced with 0.8 parts by mass of 1-hexanol.
The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 7] Polymerization was carried out in the same manner as in Example 5, except that 2 parts by mass of cetyl alcohol in Example 5 was replaced with 0.7 parts by mass of 1-pentanol.
The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 8] Polymerization was carried out in the same manner as in Example 5 except that 2 parts by mass of cetyl alcohol in Example 5 was replaced with 0.5 parts by mass of 1-propanol.
The method of measuring the polymerization rate and the particle size is the same as in Example 1.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 5 except that alcohols were not added to the monomer solution. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

Table 2 shows the evaluation results obtained in Examples 5 to 8 and Comparative Example 2.

[0041]

[Table 2]

Example 9 To 130 parts by mass of distilled water, 3.5 parts by mass of sodium rosinate (manufactured by Harima Kasei Co., Ltd.), 0.3 part by mass of sodium hydroxide, sodium naphthalenesulfonate and formaldehyde were combined. The condensate is 1.
0 parts by mass, 0.5 parts by mass of sodium hydrogen sulfite at 40 ° C.
And dissolved to prepare an aqueous rosinate solution. 80 parts by mass of 2-chloro-1,3-butadiene, 2-methyl-1,3
A monomer solution was prepared by dissolving 0.2 parts by mass of n-dodecyl mercaptan and 2 parts by mass of cetyl alcohol (1-hexadecanol) in 20 parts by mass of butadiene. An aqueous rosinate solution and a monomer solution were charged into a reactor having an internal volume of 5 liters, and the mixture was stirred in a nitrogen atmosphere at 30 ° C. for 10 minutes for emulsification. Then, the temperature was raised to 35 ° C over 20 minutes, and when the liquid temperature became stable at 35 ° C, a 2 mass% aqueous solution of potassium persulfate was used as a polymerization initiator
The mixture was added dropwise at a rate of 0.015 parts by mass (wet) per minute to start a polymerization reaction. When the conversion reached 60% by mass, an emulsion containing chloroprene monomer, distilled water, thiodiphenylamine and diethylhydroxylamine was added to terminate the polymerization. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 10] Polymerization was carried out in the same manner as in Example 9 except that 2 parts by mass of cetyl alcohol in Example 9 was replaced with 0.8 parts by mass of 1-hexanol. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 11] Polymerization was carried out in the same manner as in Example 9 except that 2 parts by mass of cetyl alcohol in Example 9 was replaced with 0.7 parts by mass of 1-pentanol. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Example 12] Polymerization was carried out in the same manner as in Example 9 except that 2 parts by mass of cetyl alcohol in Example 9 was replaced with 0.5 parts by mass of 1-propanol. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

[Comparative Example 3] Polymerization was carried out in the same manner as in Example 9 except that alcohols were not added to the monomer solution. The method of measuring the polymerization rate and the particle size is the same as in Example 1.

Table 3 shows the evaluation results obtained in Examples 9 to 12 and Comparative Example 3.

[0048]

[Table 3]

[0049]

As is apparent from Tables 1 to 3, the chloroprene polymer production method of the present invention (Examples 1 to 12) has a higher polymerization rate than the conventional production method (Comparative Examples 1 to 3). It is excellent in that the average particle size can be controlled to be small.

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Claims (8)

[Claims] 1. A total of 100 parts by mass of the monomer,
Radical polymerization of 2-chloro-1,3-butadiene alone or a monomer mixture containing 2-chloro-1,3-butadiene in the presence of 0.1 parts by mass or more and less than 10 parts by mass of alcohols. A method for producing a chloroprene polymer, which comprises: 2. The method for producing a chloroprene polymer according to claim 1, wherein the average particle size of the latex is 20 nm or more and less than 150 nm. 3. The maximum particle size of the latex is 50 nm or more and less than 300 nm, wherein
3. The method for producing a chloroprene polymer according to any one of 2 above. 4. The method for producing a chloroprene polymer according to claim 1, wherein the emulsifier is a rosin acid. 5. The alcohol is a substantially water-insoluble alcohol having a solubility in water at 20 ° C. of 1 g / 100 g or less.
5. The method for producing a chloroprene polymer according to any one of items 1 to 4. 6. The production of a chloroprene polymer according to any one of claims 1 to 5, wherein the alcohol is a saturated monohydric alcohol having 3 to 20 carbon atoms represented by the following formula. Method. [Chemical 1] 7. The method for producing a chloroprene polymer according to any one of claims 1 to 6, wherein the chloroprene polymer is a sulfur-modified chloroprene polymer. 8. The chloroprene polymer composition according to claim 1.