阅读说明：本技术 一种高疏松型pvc树脂的生产方法 (Production method of high-porosity PVC (polyvinyl chloride) resins ) 是由 张学明 王晶 张新华 孔秀丽 贾小波 肖恩琳 *** 张强 许永森 于 2018-07-18 设计创作，主要内容包括：一种高疏松型PVC树脂的生产方法,属于树脂合成技术领域。其特征在于,制备步骤包括：聚合釜中按重量份加入：去离子水120~150份,引发剂0.001~0.120份,分散体系0.005~0.500份；然后抽真空至0.08MPa~0.13MPa后按重量份加入氯乙烯单体100份,微球发泡剂0.1~5.0份；冷搅5~15分钟,然后升温至50℃~60℃开始聚合聚合反应；压力降为0.28MPa~0.31MPa后加入终止剂；继续搅拌10~20分钟后,回收单体,卸出浆料,在80℃~110℃下气提、干燥1h~2h即得。本发明制备的PVC树脂,具有较高的疏松度,可广泛应用于电线电缆、薄膜、透明制品、氯化改性产品等。(high-porosity PVC resin production method belongs to the technical field of resin synthesis, and is characterized in that the preparation method comprises the steps of adding 120-150 parts by weight of deionized water, 0.001-0.120 part by weight of an initiator and 0.005-0.500 part by weight of a dispersion system into a polymerization kettle, vacuumizing to 0.08-0.13 MPa, adding 100 parts by weight of vinyl chloride monomer and 0.1-5.0 parts by weight of a microsphere foaming agent, performing cold stirring for 5-15 minutes, heating to 50-60 ℃, starting polymerization reaction, adding a terminator after the pressure is reduced to 0.28-0.31 MPa, continuing stirring for 10-20 minutes, recovering the monomer, discharging slurry, and performing air stripping and drying at 80-110 ℃ for 1-2 hours.)

The production method of high-loose PVC resin is characterized by comprising the following steps:

1) adding the following components in a polymerization kettle in parts by weight: 120-150 parts of deionized water, 0.001-0.120 part of initiator and 0.005-0.500 part of dispersion system; then vacuumizing to 0.08-0.13 MPa, and adding 100 parts of vinyl chloride monomer and 0.1-5.0 parts of microsphere foaming agent according to parts by weight;

2) performing cold stirring for 5-15 minutes, and then heating to 50-60 ℃ to start a polymerization reaction; adding a terminating agent after the pressure is reduced to 0.28-0.31 MPa;

3) and (3) continuously stirring for 10-20 minutes, recovering the monomer, discharging slurry, and performing air stripping and drying at 80-110 ℃ for 1-2 hours to obtain the catalyst.

2. The process for producing kinds of highly porous PVC resins according to claim 1, wherein 130-140 parts by weight of deionized water, 0.020-0.050 part by weight of initiator, and 0.040-0.080 part by weight of dispersion system are added to the polymerization vessel in step 1).

3. The process for producing kinds of highly porous PVC resins according to claim 1, wherein the step 1) is followed by vacuum pumping to 0.09 MPa-0.1 MPa and then vinyl chloride monomer and foaming agent are added.

4. The method for producing high-porosity PVC resins of claim 1, wherein the microsphere foaming agent of step 1) has a core-shell structure, the shell of the microsphere foaming agent is a thermoplastic acrylic resin polymer, the core is spherical plastic particles composed of alkane gas, the particle size is 3-10 μm, and the foaming temperature is 80-100 ℃.

5. The method for producing kinds of highly porous PVC resins according to claim 1, wherein the amount of the microsphere foaming agent used in step 1) is 0.5-1.5 parts by weight.

6. The production method of kinds of high-porosity PVC resin according to claim 1, wherein the initiator in step 1) is a composite initiator of bis-2-ethylhexyl peroxydicarbonate and tert-butyl peroxyneodecanoate in a mass ratio of 3-7: 1-6.

7. The process for producing highly porous PVC resins according to claim 1, wherein the dispersion system in step 1) is a ternary dispersion system of hydroxypropyl methylcellulose in combination with two kinds of polyvinyl alcohols.

8. The method for producing kinds of highly porous PVC resins according to claim 1, wherein the temperature in step 2) is raised to 54-56 ℃ after the cold stirring for 8-10 minutes.

9. The method for producing kinds of highly porous PVC resins according to claim 1, wherein the gas stripping and drying are performed at 95-100 ℃ for 1.6-1.7 h in step 3).

Technical Field

production method of high loose PVC resin, belonging to the technical field of resin synthesis.

Background

At present, the total consumption of PVC is about 4300 ten thousand tons per year, the capacity of PVC resin in China is nearly 2500 ten thousand tons per year, the yield reaches about 1800 ten thousand tons per year, and the PVC resin has the figure in each field of national economic construction. With the development of VCM polymerization technology and PVC refinement, downstream customers put forward higher requirements on the quality and differentiation of PVC resin, and the high-looseness PVC resin is mainly used for soft products and modified products, such as wires and cables, films, transparent products, chlorinated modified products and the like.

At present, the preparation technology of PVC resin with loose particle structure, high porosity, large oil absorption of plasticizer and thin surface film is realized by dispersant, auxiliary dispersant, surfactant, porosity regulator and polymerization process conditions, in US4963592 novel additives capable of regulating resin molecular weight and improving resin porosity are provided, such as 2-mercapto benzothiazole, 2-mercapto benzoxazole, 2-mercapto benzimidazole, etc., in Chinese CN87101663A, magnesium hydroxide is used as main dispersant, two types of porosity regulators with different properties are used as auxiliary dispersant, water-soluble inorganic salt is used as auxiliary, suspension polymerization is carried out to prepare loose film without graft copolymer and polyvinyl chloride particles with high apparent density, and to reduce sticking substance, Chinese CN104277169A discloses a production method of special PVC resin for chlorination, in which deionized water, partial dispersant, buffer, surfactant, initiator and the like are added, in the middle of reaction, regulator, CN patents are published to reduce the porosity of Chinese patent, 101717459A, and 3652 patents are published to improve the porosity of filmChinese patent No. 102453175 discloses a preparation method of high oil absorption polyvinyl chloride resins, wherein C are adopted in a polymerization reaction system₄-C₁₀The functional assistant of n-alkane and isoalkane in the prior art has the advantages of high porosity of resin and high looseness of resin, and the functional assistant occupies in the resin and is separated from unreacted VCM monomer after polymerization is finished by adopting a steric hindrance effect in Chinese patent CN 102453175.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a production method of products, which has expanded and loose particles and is simple and easy to implement.

The technical scheme adopted by the invention for solving the technical problems is as follows: the production method of the high-porosity PVC resin is characterized by comprising the following preparation steps:

1) adding the following components in a polymerization kettle in parts by weight: 120-150 parts of deionized water, 0.001-0.120 part of initiator and 0.005-0.500 part of dispersion system; then vacuumizing to 0.08-0.13 MPa, and adding 100 parts of vinyl chloride monomer and 0.1-5.0 parts of microsphere foaming agent according to parts by weight;

2) performing cold stirring for 5-15 minutes, and then heating to 50-60 ℃ to start polymerization reaction; adding a terminating agent after the pressure is reduced to 0.28-0.31 MPa;

3) and (3) continuously stirring for 10-20 minutes, recovering the monomer, discharging slurry, and performing air stripping and drying at 80-110 ℃ for 1-2 hours to obtain the catalyst.

The foaming agent foaming and expanding principle is adopted, the foaming agent is firstly used in PVC resin suspension polymerization, the foaming agent and VCM are simultaneously added into a polymerization system, the foaming agent is uniformly dispersed in VCM particles, the foaming agent does not participate in polymerization reaction, and after the polymerization reaction is finished, the foaming temperature of the foaming agent is reached in a gas stripping process, and the foaming agent in the PVC resin particles is foamed, so that the PVC resin particles are expanded and loosened.

Preferably, the polymerization kettle in the step 1) is added with the following components in parts by weight: 130-140 parts of deionized water, 0.020-0.050 part of initiator and 0.040-0.080 part of dispersion system. The preferable weight part can form an environment more suitable for the co-dispersion of the foaming agent and the VCM, the foaming agent is more uniformly dispersed in the VCM particles, and the product quality is more stable.

Preferably, the step 1) is followed by vacuum pumping to 0.09 MPa-0.1 MPa and then vinyl chloride monomer and foaming agent are added.

Preferably, the microsphere foaming agent in the step 1) has a core-shell structure, the shell of the microsphere foaming agent is a thermoplastic acrylic resin polymer, the core is spherical plastic particles consisting of alkane gas, the particle size is 3-10 micrometers, and the foaming temperature is 80-100 ℃. The foaming agent is an expandable microsphere foaming agent, and the volume of the foaming agent can be rapidly expanded to several times to dozens of times of the volume of the foaming agent after heating. Fully meets the process requirements of the invention.

Preferably, the amount of the microsphere foaming agent in the step 1) is 0.5-1.5 parts by weight. When the amount of the foaming agent is too small, the effect is not obvious, and when the amount of the foaming agent is too large, the shape of resin particles is damaged, and the later-stage processing application is influenced.

The initiator is an initiator with a half-life period of 2-3 h at the polymerization temperature, and the inventor finds that a single initiator is difficult to meet the comprehensive requirements of a reaction system at the same time, a composite initiator system with high, medium and low activity is used, and two or more of azo initiators and peroxide initiators such as azobisisoheptonitrile, bis-2-ethylhexyl peroxydicarbonate (EHP), tert-amyl peroxypivalate (TAPP) and tert-butyl peroxyneodecanoate (TBPND) can be selected to achieve the basic object of the invention.

The dispersant can be two-component dispersion system of hydroxypropyl methyl cellulose and polyvinyl alcohol, ternary dispersion system of hydroxypropyl methyl cellulose and two kinds of polyvinyl alcohol or kinds of composite polyvinyl alcohol dispersion systems of two or more kinds, preferably, the dispersion system in the step 1) is ternary dispersion system of hydroxypropyl methyl cellulose and two kinds of polyvinyl alcohol, and the preferred dispersant can achieve products with better physical and chemical properties.

Preferably, the cold stirring in the step 2) is carried out for 8-10 minutes, and then the temperature is increased to 54-56 ℃ to start the reaction.

Preferably, in the step 3), the gas is stripped and dried for 1.6 to 1.7 hours at the temperature of 95 to 100 ℃.

The terminating agent can terminate the polymerization reaction of the chloroethylene and improve the whiteness of the resin. Alternative terminators are bisphenol A, thiosemicarbazone, diethylhydroxylamine or complex terminator lamps of several components, preferably diethylhydroxylamine.

The amount of the terminator is 0.001 to 0.300 part by weight, preferably 0.010 to 0.050 part by weight.

Compared with the prior art, the high-porosity PVC resin has the beneficial effects that the foaming and expanding principle of the foaming agent is adopted, the foaming agent is firstly used in the suspension polymerization of the PVC resin, the foaming agent and the VCM are simultaneously added into a polymerization system, so that the foaming agent is uniformly dispersed in VCM particles, the foaming agent does not participate in the polymerization reaction, and after the polymerization reaction is finished, the foaming temperature of the foaming agent is reached in the gas stripping process, the foaming agent in the PVC resin particles is foamed, so that the PVC resin particles are expanded and loosened.

Detailed Description

The invention is further illustrated at with reference to specific examples, of which example 1 is the best mode of practice.