阅读说明：本技术 氯乙烯聚合用复合终止剂乳液及制备方法 (Composite terminator emulsion for vinyl chloride polymerization and preparation method thereof ) 是由 刘浩 王晶 张新华 蔡振华 李兆华 张磊 刘容德 王晓敏 梁斌 高磊 孙丽朋 于 2019-08-22 设计创作，主要内容包括：本发明属于树脂合成技术领域,具体的涉及一种氯乙烯聚合用复合终止剂乳液及制备方法。包括乳化剂和复合终止剂,乳化剂由聚氧乙烯失水山梨醇醚单月桂酸酯和失水山梨醇单油酸酯复配而成,复合终止剂由季戊四醇类十二硫代丙酯、三乙二醇醚-二(3-叔丁基-4-羟基-5-甲基苯基)丙酸酯和N-异丙基羟胺复配组成。本发明所述的氯乙烯聚合用复合终止剂乳液,不仅能够起到良好的氯乙烯聚合终止效果、提高树脂的热稳定性能,还具有优良的机械搅拌稳定性,以便在搅拌强度较高的聚合条件下使用,制备方法简单,易于实施。(The invention belongs to the technical field of resin synthesis, and particularly relates to a composite terminator emulsion for vinyl chloride polymerization and a preparation method thereof. The composite terminator is prepared by compounding pentaerythritol dodecyl thionate, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine. The composite terminator emulsion for vinyl chloride polymerization not only can play a good role in terminating vinyl chloride polymerization and improving the thermal stability of resin, but also has excellent mechanical stirring stability so as to be used under the polymerization condition with higher stirring strength, and the preparation method is simple and easy to implement.)

1. A composite terminator emulsion for vinyl chloride polymerization comprises an emulsifier and a composite terminator, and is characterized in that: the emulsifier is compounded by polyoxyethylene sorbitan monolaurate and sorbitan monooleate, and the compound terminator is compounded by pentaerythritol dodecyl thiopropionate, triethylene glycol ether-di (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropyl hydroxylamine.

2. The composite terminator emulsion for vinyl chloride polymerization according to claim 1, characterized in that: the dosage of the emulsifier is 8-13% of the total mass of the composite terminator.

3. The composite terminator emulsion for vinyl chloride polymerization according to claim 1, characterized in that: the compounding mass ratio of the polyoxyethylene sorbitan monolaurate to the sorbitan monooleate is 3: 1-5: 1.

4. The composite terminator emulsion for vinyl chloride polymerization according to claim 1, characterized in that: the compound terminator comprises pentaerythritol dodecyl thiopropyl ester, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine in a compounding mass ratio of 3:3: 4-4: 4: 2.

5. The composite terminator emulsion for vinyl chloride polymerization according to claim 1, characterized in that: the mass concentration of the composite terminator is 20-30%.

6. A method for preparing a composite terminator emulsion for vinyl chloride polymerization according to claim 1, characterized in that: adding pentaerythritol dodecyl thiopropionate, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine into deionized water according to the mass parts, then adding polyoxyethylene sorbitan monolaurate and sorbitan monooleate, and shearing and emulsifying by using an emulsifying shearing machine to prepare the composite terminator emulsion for vinyl chloride polymerization.

7. The method for preparing a composite terminator emulsion for vinyl chloride polymerization according to claim 6, characterized in that: shearing and emulsifying for 25-30 min.

Technical Field

The invention belongs to the technical field of resin synthesis, and particularly relates to a composite terminator emulsion for vinyl chloride polymerization and a preparation method thereof.

Background

The terminating agent stops or significantly reduces the reaction rate by combining with residual initiator reactive radicals and residual initiator to form inactive compounds, which effectively protects the polymer from damage by thermal oxygen aging during stripping and subsequent processing. The terminator is added when the polymerization reaction reaches a set end point, and commonly used terminators are bisphenol A, thiosemicarbazone, BHT, and the like. A single terminator often cannot meet the requirements of efficiently terminating the polymerization reaction and improving the thermal stability of the resin at the same time, and the terminator is developing towards the functional compound direction of both chain termination and improving the thermal stability of PVC.

CN201110380532 discloses a preparation method and a use method of a polyvinyl chloride resin terminator, wherein the terminator is an oil-soluble composite liquid terminator and is mainly compounded by HKY-10, a benzofuranone antioxidant and a phosphite antioxidant. Wherein HKY-10 is a liquid antioxidant prepared by dissolving 2, 6-di-tert-butyl-4- (1-phenylethyl) phenol in an organic solvent. The terminator is added in the polymerization reaction process, so that the aging whiteness of the PVC resin product can be improved. As the terminator is added in the polymerization reaction process, antioxidant components in the terminator such as HKY-10, benzofuranone antioxidants and phosphite antioxidants tend to capture free radicals in the polymerization reaction process, so that the polymerization time is prolonged, and the dosage of a PVC initiator is increased.

CN103435725A discloses an aqueous emulsion type polyvinyl chloride resin terminator and a preparation method thereof, wherein the terminator comprises the following raw materials in parts by weight: 70-140 parts of a stabilizer (15-27 parts of a metal soap stabilizer, 35-48 parts of phosphite ester, 20-65 parts of an epoxy compound), 18-42 parts of a phenol antioxidant, 0.1-0.3 part of a light stabilizer, 4-18 parts of a polymerization inhibitor, 13-96 parts of an emulsifier, 1-8 parts of a dispersing agent and 100-320 parts of water, wherein the stabilizer and the phenol antioxidant are placed in a stirrer to be heated and dissolved, the temperature is reduced to normal temperature after heat preservation, then the light stabilizer and the polymerization inhibitor are added, and the mixture is stirred uniformly to obtain a mixed terminator solution. And adding an emulsifier into the mixed terminator solution, heating to 40-60 ℃, uniformly stirring, and mixing the emulsion. And simultaneously mixing the dispersing agent and water, stirring and heating to 80-100 ℃ to obtain a dispersing solution. And finally, adding the dispersion solution into the mixed emulsion to obtain the aqueous emulsion type polyvinyl chloride terminator. The aqueous emulsion type terminator contains the phosphite stabilizer, so that the hydrolysis of the phosphite stabilizer is easily caused, and the stabilizing effect of the terminator is reduced.

CN107973869 discloses a polyvinyl chloride free radical type aqueous environment-friendly high-efficiency terminator and application thereof, which comprises the following raw materials in parts by weight: 15-20 parts of a free radical type aqueous polymerization inhibitor, 20-24 parts of a water-soluble heat stabilizer and the balance of water, wherein the sum of the parts by weight of the raw materials is 100 parts. The free radical type aqueous polymerization inhibitor is 4-oxygen-2, 2,6, 6-tetramethyl piperidine-1-oxygen radical, and the water-soluble heat stabilizer is acetate or propionate. The high-efficiency terminator prepared by the method can improve the thermal stability of the resin and improve the whiteness and the ageing resistance of the resin. The polymerization inhibitor 4-oxo-2, 2,6, 6-tetramethyl piperidine-1-oxygen free radical used in the invention is orange red, and is easy to influence the chromaticity of PVC products.

Therefore, there is a need to find a new composite terminator emulsion for vinyl chloride polymerization and a preparation method thereof.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the composite terminator emulsion for vinyl chloride polymerization can not only have good vinyl chloride polymerization termination effect and improve the thermal stability of resin, but also has excellent mechanical stirring stability so as to be used under the polymerization condition with higher stirring strength; the invention also provides a preparation method thereof.

The composite terminator emulsion for vinyl chloride polymerization comprises an emulsifier and a composite terminator, wherein the emulsifier is compounded by polyoxyethylene sorbitan monolaurate and sorbitan monooleate, and the composite terminator is compounded by pentaerythritol dodecyl thiodipropyl ester, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine.

Wherein:

the dosage of the emulsifier is 8 to 13 percent of the total amount of the composite terminator.

The compounding mass ratio of the polyoxyethylene sorbitan monolaurate to the sorbitan monooleate is 3: 1-5: 1.

The compound terminator comprises pentaerythritol dodecyl thiopropyl ester, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine in a compounding mass ratio of 3:3: 4-4: 4: 2.

The mass concentration of the composite terminator is 20-30%.

The preparation method of the composite terminator emulsion for vinyl chloride polymerization specifically comprises the steps of adding pentaerythritol dodecyl thiopropyl ester, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine into deionized water according to the mass parts, then adding polyoxyethylene sorbitan monolaurate and sorbitan monooleate, and shearing and emulsifying by using an emulsifying shearing machine to prepare the composite terminator emulsion for vinyl chloride polymerization.

Wherein:

shearing and emulsifying for 25-30 min by using an emulsifying shearing machine.

Compared with the prior art, the invention has the following beneficial effects:

the composite terminator emulsion for vinyl chloride polymerization not only can play a good role in terminating vinyl chloride polymerization and improving the thermal stability of resin, but also has excellent mechanical stirring stability so as to be used under the polymerization condition with higher stirring strength, and the preparation method is simple and easy to implement.

Detailed Description

The present invention is further described below with reference to examples.

Examples 1 to 10

The composite terminator emulsion for vinyl chloride polymerization comprises an emulsifier and a composite terminator, wherein the emulsifier is compounded by polyoxyethylene sorbitan monolaurate and sorbitan monooleate, and the composite terminator is compounded by pentaerythritol dodecyl thiodipropyl ester, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine.

The formulations of the complex terminator emulsions for vinyl chloride polymerization described in examples 1 to 10 are shown in Table 1.

The invention relates to a preparation method of a composite terminator emulsion for vinyl chloride polymerization, which comprises the steps of adding pentaerythritol dodecyl thiopropionate, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine into deionized water according to the mass parts, then adding sorbitan monooleate and polyoxyethylene sorbitan monolaurate, and shearing and emulsifying for 30min by using an emulsifying shearing machine to prepare the vinyl chloride polymerization composite terminator emulsion with good mechanical stirring stability.

TABLE 1 EXAMPLES 1-10 raw materials quality ratio Table

Comparative examples 1 to 8

The formulations of the complex terminator emulsions for vinyl chloride polymerization described in comparative examples 1 to 8 are shown in Table 2.

The general preparation method of the composite terminator emulsions for vinyl chloride polymerization corresponding to comparative examples 1 to 8 was as follows:

a preparation method of a composite terminator emulsion for vinyl chloride polymerization specifically comprises the steps of adding pentaerythritol dodecyl thiopropionate, triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropyl hydroxylamine into deionized water according to the mass parts, then adding sorbitan monooleate and polyoxyethylene sorbitan monolaurate, and shearing and emulsifying for 30min by using an emulsifying shearing machine to prepare the vinyl chloride polymerization composite terminator emulsion with good mechanical stirring stability.

When the above-mentioned substances are not included in the raw materials, the steps in the above-mentioned production method are omitted and no addition is made. Taking comparative example 2 as an example, when pentaerythritol-type dodecyl dithionate is not present in the starting material, it is not added, and the preparation method is as follows:

adding triethylene glycol ether-bis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine into deionized water according to the mass parts, then adding sorbitan monooleate and polyoxyethylene sorbitan monolaurate, and shearing and emulsifying for 30min by using an emulsifying shearing machine to prepare the vinyl chloride polymerization composite terminator emulsion with good mechanical stirring stability.

TABLE 2 quality ratio table of comparative examples 1-8

The polymerization of vinyl chloride and termination of the polymerization in examples 1 to 10 and comparative examples 1 to 8 were carried out according to the following procedures and conditions: 2.3kg of desalted water, 9g of a 5% aqueous polyvinyl alcohol PVA80 solution, 6.4g of a 3% aqueous hydroxypropyl methylcellulose E50 solution, 0.265g of tert-butyl peroxyneodecanoate having a content of 75% and 0.530g of tert-amyl peroxypivalate having a content of 75% were placed in a 5L stainless steel autoclave equipped with two layers of bilobalt. Pumping the pressure in the kettle to be lower than-0.09 MPa, adding 1kg of vinyl chloride monomer, starting stirring, controlling the rotating speed to be 450rpm, firstly stirring and mixing for 10min at normal temperature, then raising the temperature of the kettle to be 58.0 ℃, and starting reaction timing after the temperature is stable. When the pressure drop in the autoclave reached 0.20MPa, 0.6g of the composite terminator emulsion (the composite terminator emulsions prepared in examples 1 to 10 and comparative examples 1 to 8) was charged into the autoclave. The temperature of the polymerization kettle is continuously controlled to be 58 +/-0.5 ℃, and the pressure drop in the polymerization kettle within 60min is observed and recorded to represent the terminating efficiency of the terminating agent (the smaller the pressure drop is, the higher the terminating efficiency of the terminating agent is, and the lower the terminating efficiency is, the reverse is). And recovering unreacted vinyl chloride monomer in the polymerization kettle, centrifugally dewatering the obtained slurry, and drying in a 60 ℃ circulating air drying oven for 6 hours to obtain PVC resin powder. And carrying out aging whiteness test on the prepared PVC resin powder according to GB/T15595-2008.

The terminating efficiency and the aged whiteness of the composite terminator emulsions prepared in examples 1 to 10 and comparative examples 1 to 8 are shown in Table 3.

TABLE 3 comparison of mechanical agitation particle size stabilization of terminating agent, terminating efficiency and aged whiteness of resin

As can be seen from examples 1 to 10 and comparative examples 1 to 8, the composite terminator composed of pentaerythritol-based dodecyl thiopropionate, triethylene glycol ether-bis (3-t-butyl-4-hydroxy-5-methylphenyl) propionate and N-isopropylhydroxylamine has good effects of synergistically terminating polymerization and synergistically improving the aged whiteness of the resin, and can not only achieve a good effect of terminating polymerization of vinyl chloride, but also effectively improve the aged whiteness of the resin. The dosage of the emulsifier compounded by the polyoxyethylene sorbitan monolaurate and the sorbitan monooleate is 8-13% of the total amount of the composite terminator, and when the compounding ratio of the polyoxyethylene sorbitan monolaurate to the sorbitan monooleate is 3: 1-5: 1, the composite terminator emulsion has good mechanical stirring stability, so that the composite terminator has stable particle size and distribution under a strong mechanical stirring condition, the composite terminator is favorably and uniformly dispersed in a polymerization system and PVC resin pores, and the effects of terminating the composite terminator and improving the thermal stability of the resin are better exerted.