JP5428305B2 - Method for producing chloroprene polymer latex for vulcanized rubber production - Google Patents

Description

  The present invention relates to a chloroprene polymer latex for producing a vulcanized rubber and a method for producing the same, and more specifically, for producing a vulcanized rubber capable of obtaining a vulcanized rubber product having excellent mechanical properties and wear resistance by immersion molding. The present invention relates to a chloroprene polymer latex and a method for producing the latex.

  Among various synthetic rubbers, chloroprene rubber has a good balance of mechanical properties, heat aging resistance, weather resistance, ozone resistance, oil resistance, chemical resistance, etc., so it can be used in a wide range of applications such as various industrial rubber parts and adhesives. Is used. Among them, they are often used as chloroprene polymer latex, not as a chip-like raw material rubber, in water-based adhesive applications, asphalt modifier applications, and immersion molding applications. In particular, in dip molding applications, chloroprene polymer latex is positioned as one of the main raw materials for gloves for household use, industrial use, and surgical use.

  Vulcanized rubber used as gloves is required to have excellent mechanical properties such as elongation at break and strength at break and abrasion resistance. In particular, in the case of industrial gloves, the above-described characteristics that can withstand the tearing and opening of gloves due to harsh work are essential, and in addition, chemical resistance and oil resistance are also required.

  In general, to produce vulcanized rubber products by immersion molding using chloroprene polymer latex, filler, reinforcing agent, anti-aging agent, plasticizer, zinc oxide, vulcanization accelerator, sulfur are added to chloroprene polymer latex. Etc., and a latex composition to which an emulsifier, a viscosity modifier and a pH adjuster are added if necessary, and a rubber film is immersed in a mold impregnated with a flocculant Is formed, heated as it is in an oven or the like, dried and vulcanized. Here, in order to obtain a vulcanized rubber having a desired film thickness by immersion molding, the solids content of the latex needs to be at least 50%, and this can be achieved by a normal chloroprene emulsion polymerization method. It is necessary to increase the polymerization conversion rate. The chloroprene polymer latex thus obtained is highly crosslinked in the latex particles until the insoluble content when the isolated polymer is made into a 1% by weight toluene solution exceeds 90%, and the Mooney viscosity ( ML (1 + 4) 100 ° C.) has a gel structure exceeding 200 (for example, see Non-Patent Document 1). Furthermore, since the rubber film obtained from the latex having such a gel structure has an appropriate strength, there is an advantage that there is no sagging deformation in an unvulcanized state and the workability is excellent.

  However, when using chloroprene polymer latex in a highly crosslinked gel state and producing vulcanized rubber by immersion molding, there is a large difference between the crosslinking density of the polymer in the original latex particles and the crosslinking density between latex particles. , The stress at the time of deformation is concentrated between the particles having a low degree of crosslinking, and the mechanical properties such as elongation at break and strength at break are not sufficient. When the resistance is further reduced and the elongation at break is improved, there is a problem that the wear resistance is remarkably impaired.

Emulsion Latex Handbook Editorial Committee, “Emulsion Latex Handbook”, first edition, Taiseisha Co., Ltd., March 1975, p. 151-p. 155

  The present invention has been made in view of the above-described problems, and its purpose is a chloroprene polymer latex capable of giving a vulcanized rubber product by immersion molding, which has improved mechanical properties such as breaking strength and is excellent. It is an object of the present invention to provide a chloroprene polymer latex capable of providing a vulcanized rubber that can be compatible with wear resistance.

  As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have reduced the cross-linking of the polymer having a gel structure in the latex particles, and obtained a vulcanized rubber produced by immersion molding. By reducing the unevenness of the crosslink density, it was found that it has excellent mechanical properties and wear resistance, and has led to the present invention. That is, the present invention contains a chloroprene polymer having a structure derived from 2-chloro-1,3-butadiene derived from 91 to 100% by weight and a structure derived from 2,3-dichloro-1,3-butadiene derived from 0 to 9% by weight. A chloroprene polymer latex for producing vulcanized rubber, wherein the chloroprene polymer has a 1% by weight toluene insoluble content of 20 to 85% by weight, and a method for producing the latex.

  The present invention is described in detail below.

  The chloroprene polymer contained in the chloroprene polymer latex of the present invention has a structure of 91 to 100% by weight derived from 2-chloro-1,3-butadiene (chloroprene) and a structure derived from 2,3-dichloro-1,3-butadiene. ~ 9% by weight. When the structure derived from 2,3-dichloro-1,3-butadiene in the chloroprene polymer exceeds 9% by weight, the cold resistance of the vulcanized rubber obtained by immersion molding is impaired, and the flexibility in a low temperature environment is significantly impaired. It is. If it is 9% by weight, the flexibility in a low temperature environment is excellent.

  The chloroprene polymer contained in the chloroprene polymer latex of the present invention includes a structure derived from 2-chloro-1,3-butadiene, a structure derived from 2,3-dichloro-1,3-butadiene, and 2-chloro-1 , 3-butadiene and a structure derived from a comonomer copolymerizable with 2,3-dichloro-1,3-butadiene. The comonomer copolymerizable with 2-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene is not particularly limited as long as it is based on a monomer capable of radical polymerization. For example, monovinyl compounds such as acrylonitrile, methacrylonitrile and vinylidene chloride, aromatic vinyl compounds such as styrene and α-methylstyrene, unsaturated group-containing carboxylic acids such as acrylic acid and methacrylic acid, acrylic acid esters and methacrylic acid Examples thereof include unsaturated group-containing carboxylic acid esters such as esters, conjugated diene compounds such as isoprene, 1,3-butadiene, and 1-chloro-1,3-butadiene, and may be used alone or in combination of two or more. . The composition ratio in the case of having the structure derived from the comonomer is such that the vulcanized rubber obtained by immersion molding exhibits characteristics as a chloroprene rubber, and the structure derived from 2-chloro-1,3-butadiene and 2,3-dichloro The structure derived from -1,3-butadiene is preferably 88% by weight or more and less than 100% by weight, and the structure derived from the comonomer is more than 0% by weight and 12% by weight or less. Furthermore, in order to exert the characteristics as a chloroprene rubber strongly, it is particularly preferably more than 0% by weight and 8% by weight or less.

  The amount of insoluble matter when the chloroprene polymer isolated from the chloroprene polymer latex of the present invention is made into a 1% by weight toluene solution is 20 to 85% by weight. When the 1% by weight toluene insoluble content is less than 20% by weight, the polymer crosslinking density in the latex particles is low, the crosslinking density of the vulcanized rubber obtained by immersion molding is not sufficiently high, and the modulus (extension stress) is low. And impairs wear resistance. If it exceeds 85% by weight, the polymer crosslinking density in the latex particles becomes too high, and when vulcanized rubber is produced by dip molding, the difference between the crosslinking density of the polymer in the latex particles and the crosslinking density between the latex particles is inherent. Therefore, the stress at the time of deformation is concentrated between the particles having a low degree of crosslinking, and mechanical properties such as elongation at break and strength at break are impaired. Furthermore, when the crosslink density between particles is reduced by reducing the vulcanizing agent and the elongation at break is improved, the modulus is remarkably impaired. If the 1% by weight toluene insoluble content of the polymer is 20 to 85% by weight, the vulcanized rubber obtained by immersion molding has good mechanical properties and wear resistance, but the 1% by weight toluene insoluble content is 40%. If it is -80 weight%, the vulcanized rubber which has the further outstanding mechanical characteristic will be obtained, and it is especially preferable. Here, as a method of measuring the wear resistance, in the case of the Taber abrasion test, a vulcanized sheet having a thickness of 0.5 mm is prepared and attached to the Taber abrasion tester, and the wear wheel is specified times under a load condition of 23 ° C. and 250 g. It is shown by wear loss when running. If the weight loss after running 3,000 times under the same conditions is less than 0.4 g, it can be determined that the wear resistance is good, and if it is less than 0.3 g, it is particularly excellent and more preferred.

  The chloroprene polymer latex of the present invention may contain various additives as required. Examples of the additive include an antioxidant, an antiseptic, a pH stabilizer, an emulsion stabilizer, a viscosity modifier, and an antifreezing agent.

  The chloroprene polymer latex of the present invention contains 92.5 to 100 parts by weight of 2-chloro-1,3-butadiene and 0 to 7.5 parts by weight of 2,3-dichloro-1,3-butadiene at 20 to 55 ° C. It can manufacture by carrying out emulsion polymerization to polymerization conversion rate 85-95% at temperature. Further, it may be produced using more than 0 parts by weight of a comonomer copolymerizable with 2-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene and not more than 12 parts by weight.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, a chain transfer agent may be used. The chain transfer agent is not particularly limited as long as it is a compound used for general radical polymerization. For example, alkyl mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, octyl mercaptan, diethyl xanthogen disulfide, dibutyl Examples thereof include xanthogen sulfides such as xanthogen disulfide and diisopropylxanthogen disulfide, benzyl iodide, iodoform, and the like, which are used alone or in combination of two or more. The amount of the chain transfer agent is not particularly limited, but in order to achieve a 1% by weight toluene-insoluble content of the polymer isolated from the resulting polymer latex as intended, 100 parts by weight of monomers other than the chain transfer agent It is preferable that it is 0.05-0.2 weight part with respect to this.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, the emulsifier is not particularly limited as long as it is a surfactant generally used for emulsion polymerization. Carboxylate type, sulfonate type, sulfate Type anionic emulsifiers and nonionic emulsifiers, etc., specifically, alkali metal salts of disproportionated rosin acid, alkali metal salts of rosin acid, higher fatty acid alkali metal salts, alkyl sulfonates, alkyl aryls Examples include sulfonates, alkyl sulfates, alkylaryl sulfates, condensates of sodium naphthalenesulfonate and formaldehyde, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, sorbitan fatty acid esters, polyoxyethylene acyl esters, etc. , Alone or in combination of two or more It is possible. Although the optimum range of the amount of each emulsifying dispersant added varies depending on the type, the emulsion polymerization can be carried out stably, and as a range for obtaining vulcanized rubber by immersion molding, in the case of an anionic emulsifier, 100 parts by weight of the monomer mixture 1 to 8 parts by weight is preferable, and 2 to 6 parts by weight is particularly preferable. Since the nonionic emulsifier hardly causes latex aggregation due to the coagulant, the amount used is limited, and it is preferably 2 parts by weight or less based on 100 parts by weight of the monomer mixture.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, the polymerization initiator is not particularly limited as long as it is a free radical generating substance, and examples thereof include persulfates such as potassium persulfate and ammonium persulfate, Examples include inorganic or organic peroxides such as hydrogen oxide, paramentane hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like alone or with the above compounds and ferrous sulfate, hydrosulfite sodium, sodium A redox system using a reducing substance such as formaldehyde sulfoxylate, thiosulfate, thiosulfite, and organic amine is used.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, the polymerization temperature is 25 to 55 ° C. When the polymerization temperature is lower than 25 ° C., the vulcanized rubber obtained by dip molding of latex has a high crystallization rate, and the vulcanized rubber product becomes hard when left in a low temperature atmosphere. On the other hand, when the polymerization temperature exceeds 55 ° C., the gelation of the polymer proceeds during the polymerization, and the 1% by weight toluene-insoluble content of the polymer becomes too high. Among these, 30-53 degreeC is preferable.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, the polymerization termination conversion is 85 to 95%. When the polymerization stop conversion is lower than 85%, the solid content of the latex is low, so that a long immersion time is required to obtain a product having a target thickness in the immersion molding, which is not preferable. When the polymerization stop conversion rate exceeds 95%, the gelation of the polymer proceeds during the polymerization, and the 1% by weight toluene-insoluble content of the polymer becomes too high. Among these, the polymerization termination conversion is preferably 87 to 94%.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, it is possible to add a polymerization terminator as necessary when the polymerization is terminated. The polymerization terminator is not particularly limited as long as it is a compound that traps radicals. For example, phenothiazine, 2,2′-methylenebis- (4-methyl-6-tert-butylphenol), 2,2′-methylenebis -Radical inhibitors such as-(4-ethyl-6-t-butylphenol), 2,6-di-t-butyl-4-methylphenol, hydroquinone, 4-methoxyhydroquinone, N, N-diethylhydroxylamine and the like. These can be used alone or in combination of two or more. Although the optimum range of the addition amount of each polymerization terminator varies depending on the type, 0.01 to 100 parts by weight of the monomer as a range in which the polymerization can be surely stopped and the stability of the obtained chloroprene polymer can be secured. 5 parts by weight is preferable, and 0.02 to 2 parts by weight is particularly preferable.

  In the polymerization for obtaining the chloroprene polymer latex of the present invention, the method for removing the unreacted monomer carried out after completion of the polymerization is not particularly limited, and examples thereof include steam stripping under reduced pressure.

  In order to produce a vulcanized rubber product by immersion molding using the chloroprene polymer latex of the present invention, a normal immersion molding technique can be used. For example, the chloroprene polymer latex of the present invention may be prepared by dispersing an acid acceptor, a filler, a reinforcing agent, an anti-aging agent, a plasticizer, a lubricant, zinc oxide, a vulcanization accelerator, sulfur, etc. in water as necessary. A latex composition is prepared by adding a turbid liquid and, if necessary, an emulsifier, a viscosity modifier, and a pH regulator, and the mold of the desired vulcanized rubber molding impregnated with a coagulant such as calcium nitrate is immersed therein. As a result, a rubber film is formed on the mold. Furthermore, after the rubber film is soaked in water together with the mold, excess emulsifier and the like are washed away and then heated in an oven or the like together with the mold, dried and vulcanized.

  The chloroprene polymer latex of the present invention has a reduced polymer crosslinking density in the latex particles, and can produce a vulcanized rubber having excellent mechanical properties and wear resistance by immersion molding.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples.

<Polymer composition>
The polymer composition in the chloroprene polymer latex was determined by pyrolysis gas chromatography of the polymer obtained by spreading the chloroprene polymer latex on a petri dish and freezing it, and then lyophilizing with a vacuum dryer. The measurement was performed using a PY-2010D manufactured by FRONTIER LAB, thermally decomposed at 590 ° C., and performed at a temperature rising condition of 15 ° C./min from 40 ° C. to 300 ° C. using a DB-5 column. It quantified using the analytical curve created with the model polymer which calculated | required the composition separately by C13-NMR.

<1% by weight toluene insoluble content>
The amount of 1% by weight toluene insoluble in the polymer was determined by spreading the chloroprene polymer latex on a petri dish and freezing it, dissolving the polymer obtained by lyophilization with a vacuum dryer in toluene at a concentration of 1%, and adding it to a 100 mesh wire mesh. It was determined as the amount of insoluble matter filtered off.

<Solid content>
The solid content of the chloroprene polymer latex was evaluated from the weight change before and after drying when 2 g of chloroprene polymer latex was dried in a hot air dryer at 105 ° C. for 2 hours.

<Normal characteristics>
The normal properties of the vulcanizate are as follows: JIS K6251 (1993 version), using dumbbell-shaped No. 4 type test pieces, tensile speed 500 mm / min, conditions of 23 ° C., elongation at break, strength at break, 200% elongation stress 500% elongation stress was evaluated.

<Taber wear reduction>
To reduce the Taber abrasion of the vulcanizate, prepare a vulcanized sheet with a thickness of 0.5 mm, fix it to the sample table of the Taber abrasion tester using double-sided tape, and wear the wear wheel with a load of 250 g at 23 ° C. The weight loss after running 3,000 times was measured and evaluated.

<Low temperature characteristics>
The low temperature characteristics of the vulcanizate were measured using a viscoelasticity analyzer VR-7120 manufactured by Ueshima Seisakusho, using a vulcanized sheet with a thickness of 0.5 mm and a width of 4 mm, and a tensile strength of 10 Hz, initial strain of 1%, and amplitude of 0.1%. A temperature dispersion spectrum at strain was measured and evaluated as a peak temperature of tan δ.

Example 1
100 parts by weight of 2-chloro-1,3-butadiene and 0.10 parts by weight of n-dodecyl mercaptan were charged into a 10 L autoclave equipped with a stirrer, and 3.5 parts by weight of potassium rosinate and formaldehyde condensate of sodium naphthalenesulfonate 0 An emulsion comprising 0.7 parts by weight, 0.4 parts by weight of sodium hydroxide and 80 parts by weight of distilled water was added thereto, and after sufficiently purging with nitrogen, the mixture was emulsified by stirring. Polymerization was started by continuously dropping a 0.2 wt% aqueous potassium persulfate solution while adding a 3 wt% aqueous sodium hydrosulfite solution and controlling the jacket temperature so that the inside of the polymerization vessel was kept constant at 40 ° C.

  When the conversion ratio with respect to the monomer reached 93%, 0.03 part by weight of phenothiazine was dissolved in toluene and emulsified with an aqueous sodium dodecylbenzenesulfonate solution as a polymerization terminator to complete the polymerization. The remaining unreacted monomer was removed by a vacuum steam stripping method to obtain a chloroprene polymer latex. Table 1 shows the polymer composition, toluene-insoluble content, and solid content in the polymer latex.

一方、酸化亜鉛、硫黄、加硫促進剤ＣＡ（Ｎ，Ｎ‘−ジフェニルチオウレア）、加硫促進剤ＺｎＥＤＣ（ジエチルジチオカルバミン酸亜鉛）それぞれを１００重量部として、アンモニウムガゼイン３重量部、ナフタレンスルホン酸ナトリウムのホルマリン縮合物３重量部、蒸留水１００重量部をそれぞれ混合し、ボールミルにて１日撹拌することにより、各配合剤の安定な懸濁液を作製した。

On the other hand, zinc oxide, sulfur, vulcanization accelerator CA (N, N'-diphenylthiourea), vulcanization accelerator ZnEDC (diethyldithiocarbamate) 100 parts by weight, ammonium gazein 3 parts by weight, sodium naphthalene sulfonate 3 parts by weight of the formalin condensate and 100 parts by weight of distilled water were mixed and stirred for 1 day in a ball mill to prepare a stable suspension of each compounding agent.

  Assuming that the solid content in the chloroprene polymer latex is 100 parts by weight, 5 parts by weight of zinc oxide, 2 parts by weight of sulfur, 2.5 parts by weight of vulcanization accelerator CA, and 1 part by weight of vulcanization accelerator ZnEDC are added. The suspension was added to the chloroprene polymer latex and stirred for 1 hour to prepare a latex composition.

  A rubber plate was agglomerated and formed on the flat plate by dipping the flat plate mold dipped in a 25% calcium nitrate aqueous solution and dried in a chloroprene polymer latex composition. It was immersed in warm water at 30 ° C. together with the mold to elute water-soluble impurities, then heated for 30 minutes in a 120 ° C. hot air dryer, dried and vulcanized to obtain a 0.25 mm thick vulcanized rubber sheet. . Normal characteristics were measured. A 0.5 mm vulcanized rubber sheet was separately prepared by extending the immersion time in the same manner, and the Taber abrasion loss and low temperature characteristics were measured. These vulcanizate properties are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 2
A chloroprene polymer latex was obtained in the same manner as in Example 1 except that 0.08 parts by weight of n-dodecyl mercaptan and a polymerization temperature of 30 ° C. were used. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 3
A chloroprene polymer latex was obtained in the same manner as in Example 1 except that 0.18 parts by weight of n-dodecyl mercaptan, a polymerization temperature of 50 ° C., and a polymerization termination conversion rate of 89% were used. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 4
A chloroprene polymer latex was obtained in the same manner as in Example 1 except that 0.12 parts by weight of n-dodecyl mercaptan and a polymerization termination conversion rate of 88% were used. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 5
The same method as in Example 1 except that 93 parts by weight of 2-chloro-1,3-butadiene, 7 parts by weight of 2,3-dichloro-1,3-butadiene, and 92% conversion to polymerization termination were used. A chloroprene polymer latex was obtained. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 6
92.5 parts by weight of 2-chloro-1,3-butadiene, 7.5 parts by weight of 2,3-dichloro-1,3-butadiene, 0.08 parts by weight of n-dodecyl mercaptan, and a polymerization temperature of 30 ° C. A chloroprene polymer latex was obtained in the same manner as in Example 1 except that the polymerization termination conversion rate was 90%. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Example 7
96.5 parts by weight of 2-chloro-1,3-butadiene, 3.5 parts by weight of 2,3-dichloro-1,3-butadiene, 0.09 parts by weight of n-dodecyl mercaptan, and a polymerization temperature of 35 ° C. A chloroprene polymer latex was obtained in the same manner as in Example 1 except that the polymerization termination conversion rate was 92%. Table 1 shows the polymer composition, the amount of insoluble toluene, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 1. A vulcanized rubber having high breaking strength and modulus, and excellent wear resistance and low temperature characteristics was obtained.

Comparative Example 1
Example 1 except that 85 parts by weight of 2-chloro-1,3-butadiene, 15 parts by weight of 2,3-dichloro-1,3-butadiene, and 0.15 parts by weight of n-dodecyl mercaptan were used. A chloroprene polymer latex was obtained by this method. Table 2 shows the polymer composition, toluene-insoluble content, and solid content in the polymer latex.

実施例１と同様の配合および手法にて、クロロプレン重合体ラテックス組成物を作製した。さらに実施例１と同様の方法にて加硫ゴムシートを作製し、加硫物の常態特性、テーバー摩耗減量、低温特性を測定した。これら加硫物特性を表２に示す。破断強度およびモジュラスが高く、耐摩耗性に優れたが、ポリマー中の２，３−ジクロロ−１，３−ブタジエン量が多いため、低温特性が劣った。

A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was prepared in the same manner as in Example 1, and the normal characteristics, the Taber abrasion loss, and the low temperature characteristics of the vulcanizate were measured. These vulcanized properties are shown in Table 2. Although the breaking strength and modulus were high and the wear resistance was excellent, the low temperature characteristics were inferior due to the large amount of 2,3-dichloro-1,3-butadiene in the polymer.

Comparative Example 2
A chloroprene polymer latex was obtained in the same manner as in Example 1 except that 0.07 part by weight of n-dodecyl mercaptan, the polymerization temperature was 50 ° C., and the polymerization termination conversion was 98%. Table 2 shows the polymer composition, the toluene insoluble content, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was prepared in the same manner as in Example 1, and the normal characteristics, the Taber abrasion loss, and the low temperature characteristics of the vulcanizate were measured. These vulcanizate characteristics are shown in Table 2. The modulus was high and the wear resistance was excellent, but the polymer had too much toluene insolubles, so the elongation at break was reduced and the strength at break was poor.

Comparative Example 3
96.5 parts by weight of 2-chloro-1,3-butadiene, 3.5 parts by weight of 2,3-dichloro-1,3-butadiene, 0.18 parts by weight of n-dodecyl mercaptan, and a polymerization temperature of 56 ° C. A chloroprene polymer latex was obtained in the same manner as in Example 1 except that the polymerization termination conversion rate was 92%. Table 2 shows the polymer composition, the toluene insoluble content, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was prepared in the same manner as in Example 1, and the normal characteristics, the Taber abrasion loss, and the low temperature characteristics of the vulcanizate were measured. These vulcanizate characteristics are shown in Table 2. The modulus was high and the wear resistance was excellent, but the polymer had too much toluene insolubles, so the elongation at break was reduced and the strength at break was poor.

Comparative Example 4
Example 1 except that 93 parts by weight of 2-chloro-1,3-butadiene, 7 parts by weight of 2,3-dichloro-1,3-butadiene, a polymerization temperature of 20 ° C., and a polymerization termination conversion rate of 90% were used. A chloroprene polymer latex was obtained in the same manner as above. Table 2 shows the polymer composition, the toluene insoluble content, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 2. Since the polymer had little toluene-insoluble content, the modulus was inferior and the wear resistance was also inferior.

Comparative Example 5
94 parts by weight of 2-chloro-1,3-butadiene, 6 parts by weight of 2,3-dichloro-1,3-butadiene, 0.12 parts by weight of n-dodecyl mercaptan, and 70% polymerization termination conversion Except for the above, a chloroprene polymer latex was obtained in the same manner as in Example 1. Table 2 shows the polymer composition, the toluene insoluble content, and the solid content in the polymer latex.

  A chloroprene polymer latex composition was prepared in the same formulation and procedure as in Example 1. Further, a vulcanized rubber sheet was produced in the same manner as in Example 1, and the normal characteristics, Taber abrasion loss, and low temperature characteristics were measured. These vulcanizate characteristics are shown in Table 2. Since the polymer had little toluene-insoluble content, the modulus was inferior and the wear resistance was also inferior.

Claims (1)

92.5-100 parts by weight of 2-chloro-1,3-butadiene and 0-7.5 parts by weight of 2,3-dichloro-1,3-butadiene at a temperature of 25-55 ° C. other than the chain transfer agent 2-chloro-1,3-butadiene is characterized in that emulsion polymerization is carried out to a polymerization conversion rate of 85 to 95% using 0.05 to 0.2 parts by weight of a chain transfer agent with respect to 100 parts by weight of the monomer. A chloroprene polymer having a structure derived from 91 to 100% by weight and a structure derived from 2,3-dichloro-1,3-butadiene derived from 0 to 9% by weight, wherein the 1% by weight toluene-insoluble content of the chloroprene polymer is 20 to 85%. The manufacturing method of the chloroprene polymer latex for vulcanized rubber manufacture which is weight% .