阅读说明：本技术 一种硫醇调节的粘接型氯丁橡胶的制备方法 (Preparation method of mercaptan-regulated adhesive chloroprene rubber ) 是由 雒雄雄 刘慧彬 沈凯燕 高文龙 王禄 于 2018-07-04 设计创作，主要内容包括：本发明属粘接型氯丁橡胶制备技术领域,提供一种硫醇调节的粘接型氯丁橡胶的制备方法,以氯丁二烯为聚合单体、硫醇为调节剂,以特定配比进行的低温乳液聚合反应,改变乳化剂加入方式后,即松香皂化后直接加入水相,减少物料溶解时间,可直接起到乳化作用,克服了乳化剂反应不完全利用率低等问题,改善了产品质量稳定性。制得的粘接型氯丁橡胶,高结晶性、粘接性及可接枝等优点,质量好、性能更稳定；降低产品中终止剂残留,使其接枝性能尤为突出,能更好的与其它单体进行接枝反应,尤其是甲基丙烯酸甲酯,耐老化性能非常好,克服了国内生产的同类产品无法接枝等难题,广泛应用于胶粘剂等相关行业产品中,满足下游客户的新需求。(The invention belongs to the technical field of preparation of adhesive chloroprene rubber, and provides a preparation method of adhesive chloroprene rubber regulated by mercaptan. The prepared adhesive chloroprene rubber has the advantages of high crystallinity, adhesiveness, grafting and the like, and has good quality and more stable performance; the residual terminating agent in the product is reduced, the grafting performance is particularly outstanding, the product can better perform grafting reaction with other monomers, particularly methyl methacrylate, the aging resistance is very good, the problems that similar products produced in China cannot be grafted and the like are solved, the product is widely applied to products of related industries such as adhesives and the like, and the new requirements of downstream customers are met.)

1. A preparation method of mercaptan-regulated adhesive chloroprene rubber is characterized by comprising the following steps:

1) mixing chloroprene and mercaptan and dissolving to prepare an oil phase; then mixing with water phase for emulsification; the oil phase comprises 100 parts of chloroprene and 0.05-0.2 part of mercaptan in parts by weight; the water phase comprises 2-5 parts of emulsifier, 0.3-0.6 part of co-emulsifier, 0.1-0.5 part of strong base, 0.2-0.6 part of sodium sulfite and 105-150 parts of soft water by weight; the weight ratio of the water phase to the oil phase is 1.05-1.5: 1, and the emulsifying temperature is 15-25 ℃; after complete emulsification, adjusting the temperature of the system to be 5-20 ℃, and continuously adding a free radical initiator to initiate polymerization;

2) when the conversion rate of the polymerization reaction reaches 70-75%, adding a terminator to stop the reaction; removing unreacted monomers, adjusting the pH value to 5-7, freezing the gel, washing with water, and drying to obtain the bonding type chloroprene rubber.

2. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the mercaptan is n-dodecyl mercaptan.

3. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the emulsifier is disproportionated rosin potassium soap; the auxiliary emulsifier is beta-naphthalenesulfonic acid formaldehyde condensed sodium salt, and the strong base is potassium hydroxide.

4. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the reaction temperature is 5-15 ℃.

5. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the free radical initiator is a soft water solution of potassium persulfate and/or anthraquinone-2-sodium sulfonate.

6. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the terminator comprises, by weight, 1.5-4 parts of toluene, 0.1-0.5 part of sodium dodecyl sulfate, 0.1-0.5 part of beta-naphthalenesulfonic acid formaldehyde condensed sodium salt, 0.1-0.5 part of polymerization inhibitor, 0.1-0.5 part of antioxidant and 0.8-3 parts of soft water.

7. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the polymerization inhibitor is one or more of phenothiazine, diethylhydroxylamine and N-isopropylhydroxylamine.

8. The method of claim 1 for preparing a mercaptan modified, adhesive neoprene, wherein: the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 2246, antioxidant 300, antioxidant CA, antioxidant 164, antioxidant DNP, antioxidant MB and antioxidant 264.

Technical Field

The invention belongs to the technical field of preparation of bonding type chloroprene rubber, and particularly relates to a preparation method of mercaptan-regulated bonding type chloroprene rubber.

Background

Chloroprene rubber is a high molecular weight polymer of chloroprene monomers. Low temperature neoprene is widely used in the field of adhesives because it exhibits excellent adhesion properties due to its good crystallinity. China is a big country for shoes and case products, and the demand of the chloroprene rubber is large, so that the development of high-performance adhesive chloroprene rubber to meet the customer demand becomes urgent.

At present, the chloroprene rubber produced in China has poor crystallinity, serious product branching, no grafting and yellow appearance color and luster, and can not meet the requirements of downstream customers.

The production technology of the chloroprene rubber produced abroad is advanced, and the chloroprene rubber produces more heat, so the heat dissipation is assisted by improving the proportion of water phase in the emulsion polymerization process, and the common emulsifier disproportionated rosin is added in a mode of disproportionated rosin potassium or sodium salt. In addition, they either add different proportions of regulator at different stages or use different reaction temperatures at different stages of the reaction, or add a certain amount of regulator to the initiator or a certain amount of neutral emulsifier during the emulsification process, and their conversion is usually controlled to around 70%. The product obtained by the method has good quality, but the operation makes the production process complicated.

The invention discloses a preparation method of adhesive type chloroprene rubber, which is named as the preparation method of the adhesive type chloroprene rubber under the application number of 201010562326.5, and comprises the following steps: 1) completely dissolving chloroprene, mercaptan and a main emulsifier to prepare an oil phase; then mixing with water phase for emulsification; after complete emulsification, adjusting the temperature of the system to be 5-20 ℃, and continuously adding a free radical initiator to initiate polymerization; 2) when the conversion rate of the polymerization reaction reaches 70-75%, adding a terminator to stop the reaction; removing unreacted monomers, adjusting the pH value to 5-7, freezing the gel, washing with water, and drying to obtain the bonding type chloroprene rubber. The preparation method of the invention has simple and convenient formula and process flow, can conveniently prepare the adhesive chloroprene rubber, and the obtained product has high crystallinity, adhesiveness and grafting property, good quality and stable performance, overcomes the difficult problems that similar products produced at home in the past can not be grafted and the like, and meets the new requirements of downstream customers. However, in the preparation method, the main emulsifier is applied to the oil phase, the main emulsifier is solid, the dissolving process needs a long time, and the emulsifier needs to be subjected to emulsification after mixing reaction of water and oil phases, so that the quality stability of the finally obtained product has an unstable factor, the bonding property is difficult to reach an ideal state, the residual amount of the stabilizer in the product is relatively high, and the grafting property of the product is greatly influenced.

Disclosure of Invention

The invention aims to provide a preparation method of mercaptan-regulated adhesive chloroprene rubber, which has simple process flow and can prepare chloroprene rubber with good crystallinity, adhesiveness and grafting.

In order to achieve the above object, the present invention provides a method for preparing a thiol-regulated adhesive-type chloroprene rubber, comprising the steps of:

1) mixing chloroprene and mercaptan and dissolving to prepare an oil phase; then mixing with water phase for emulsification; the oil phase comprises 100 parts of chloroprene and 0.05-0.2 part of mercaptan in parts by weight; the water phase comprises 2-5 parts of emulsifier, 0.3-0.6 part of co-emulsifier, 0.1-0.5 part of strong base, 0.2-0.6 part of sodium sulfite and 105-150 parts of soft water by weight; the weight ratio of the water phase to the oil phase is 1.05-1.5: 1, and the emulsifying temperature is 15-25 ℃; after complete emulsification, adjusting the temperature of the system to be 5-20 ℃, and continuously adding a free radical initiator to initiate polymerization;

2) when the conversion rate of the polymerization reaction reaches 70-75%, adding a terminator to stop the reaction; removing unreacted monomers, adjusting the pH value to 5-7, freezing the gel, washing with water, and drying to obtain the bonding type chloroprene rubber.

Among them, the mercaptan is preferably n-dodecyl mercaptan.

The preparation method of the invention takes the mercaptan as the regulator, the dosage of the mercaptan has important influence on the quality of the final product and directly determines the performance of the product, so the dosage of the mercaptan in the invention is controlled to be 0.05-0.2 weight part, and the n-dodecyl mercaptan is preferably used.

The water phase comprises 2-5 parts of a main emulsifier, 0.3-0.6 part of a co-emulsifier, 0.1-0.5 part of strong base, 0.2-0.6 part of sodium sulfite and 105-150 parts of soft water by weight.

The main emulsifier is preferably disproportionated rosin potassium soap, the auxiliary emulsifier is preferably beta-naphthalenesulfonic acid formaldehyde condensed sodium salt, and the strong base is preferably potassium hydroxide.

The weight ratio of the water phase to the oil phase is 1.05-1.5: 1, and the emulsifying temperature is 15-25 ℃.

In order to ensure that the prepared adhesive chloroprene rubber has good crystallinity, the polymerization reaction temperature of the invention is 5-20 ℃, preferably 5-15 ℃.

The free radical initiator is a soft water solution of potassium persulfate and/or anthraquinone-2-sodium sulfonate (silver salt); wherein the mass concentration of the potassium persulfate is 0.1-5%, and the mass concentration of the anthraquinone-2-sodium sulfonate (silver salt) is 0.1-5%. The amount of the initiator is appropriately adjusted depending on the rate of polymerization.

The terminator comprises, by weight, 1.5-4 parts of toluene, 0.1-0.5 part of sodium dodecyl sulfate, 0.1-0.5 part of beta-naphthalenesulfonic acid formaldehyde condensed sodium salt, 0.1-0.5 part of polymerization inhibitor, 0.1-0.5 part of antioxidant and 0.8-3 parts of soft water. Wherein the polymerization inhibitor is used for terminating the polymerization reaction, and the antioxidant is used for preventing deterioration.

Wherein the polymerization inhibitor can be one or more of phenothiazine, diethylhydroxylamine and N-isopropylhydroxylamine.

In addition, the antioxidant can be one or more of antioxidant 1010, antioxidant 1076, antioxidant 2246, antioxidant 300, antioxidant CA, antioxidant 164, antioxidant DNP, antioxidant MB, and antioxidant 264.

After unreacted monomers are removed, the preparation method preferably uses 30% acetic acid solution to adjust the pH value to 5-7.

The preparation method of the invention uses chloroprene as a polymerization monomer and mercaptan as a regulator, and carries out low-temperature emulsion polymerization reaction in a specific proportion, the adopted polymerization reaction formula and the process flow are simple and convenient, the addition mode of the emulsifier is changed, namely the water phase is directly added after rosin saponification, the material dissolution time is reduced, the added emulsifier can directly play an emulsification role without reaction, the problems of low incomplete utilization rate of the emulsifier reaction and the like are overcome, and the product quality stability is improved. The weight-average molecular weight of the bonding type chloroprene rubber prepared by the method is 400000-1000000, the number-average molecular weight is 200000-500000, the molecular weight distribution is 2-3, and the obtained product has the advantages of high crystallinity, bonding property, grafting property and the like, and is good in quality and more stable in performance; the chloroprene rubber prepared by the method adjusts the proportion of the terminating agent, reduces the residue of the terminating agent in the product, has more outstanding grafting performance than before, can better perform grafting reaction with other monomers, particularly methyl methacrylate, has very good ageing resistance, overcomes the difficult problems that like products produced at home cannot be grafted and the like at present, can be widely applied to products of related industries such as adhesives and the like, and meets the new requirements of downstream customers.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the scope of the invention.