CN113461844A - Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin - Google Patents
Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin Download PDFInfo
- Publication number
- CN113461844A CN113461844A CN202110716419.7A CN202110716419A CN113461844A CN 113461844 A CN113461844 A CN 113461844A CN 202110716419 A CN202110716419 A CN 202110716419A CN 113461844 A CN113461844 A CN 113461844A
- Authority
- CN
- China
- Prior art keywords
- polymerization
- initiator
- polyvinyl chloride
- degree
- solid phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011347 resin Substances 0.000 title claims abstract description 102
- 229920005989 resin Polymers 0.000 title claims abstract description 102
- 239000004801 Chlorinated PVC Substances 0.000 title claims abstract description 41
- 229920000457 chlorinated polyvinyl chloride Polymers 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 41
- 239000007790 solid phase Substances 0.000 title claims abstract description 32
- 238000006116 polymerization reaction Methods 0.000 claims abstract description 119
- 239000004800 polyvinyl chloride Substances 0.000 claims abstract description 107
- 229920000915 polyvinyl chloride Polymers 0.000 claims abstract description 106
- 239000003999 initiator Substances 0.000 claims abstract description 79
- 239000000463 material Substances 0.000 claims abstract description 54
- 238000006243 chemical reaction Methods 0.000 claims abstract description 46
- 239000002002 slurry Substances 0.000 claims abstract description 24
- 238000007599 discharging Methods 0.000 claims abstract description 17
- 238000001035 drying Methods 0.000 claims abstract description 16
- 230000003213 activating effect Effects 0.000 claims abstract description 7
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 7
- 230000001502 supplementing effect Effects 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 54
- 238000000034 method Methods 0.000 claims description 41
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 claims description 27
- 239000000178 monomer Substances 0.000 claims description 27
- 239000002270 dispersing agent Substances 0.000 claims description 25
- 230000008569 process Effects 0.000 claims description 21
- 238000002360 preparation method Methods 0.000 claims description 18
- 239000008367 deionised water Substances 0.000 claims description 16
- 229910021641 deionized water Inorganic materials 0.000 claims description 16
- 239000003795 chemical substances by application Substances 0.000 claims description 15
- 239000004094 surface-active agent Substances 0.000 claims description 13
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 12
- 238000006136 alcoholysis reaction Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 12
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 10
- 238000001994 activation Methods 0.000 claims description 9
- 238000009826 distribution Methods 0.000 claims description 8
- 230000003472 neutralizing effect Effects 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 5
- 239000000498 cooling water Substances 0.000 claims description 5
- DTOJBTUWYBSXIZ-UHFFFAOYSA-N cumene;7,7-dimethyloctaneperoxoic acid Chemical compound CC(C)C1=CC=CC=C1.CC(C)(C)CCCCCC(=O)OO DTOJBTUWYBSXIZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 claims description 5
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 claims description 5
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 claims description 5
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 claims description 5
- 239000012452 mother liquor Substances 0.000 claims description 5
- 230000004913 activation Effects 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 3
- 238000005660 chlorination reaction Methods 0.000 abstract description 22
- 150000003254 radicals Chemical class 0.000 abstract description 15
- 230000000694 effects Effects 0.000 abstract description 12
- 230000000977 initiatory effect Effects 0.000 abstract description 12
- 238000010532 solid phase synthesis reaction Methods 0.000 abstract description 6
- 239000002245 particle Substances 0.000 description 45
- 239000011164 primary particle Substances 0.000 description 19
- 239000011148 porous material Substances 0.000 description 16
- 239000000047 product Substances 0.000 description 14
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 12
- 229910052801 chlorine Inorganic materials 0.000 description 12
- 239000000460 chlorine Substances 0.000 description 12
- 238000009792 diffusion process Methods 0.000 description 10
- 239000008187 granular material Substances 0.000 description 9
- 239000002086 nanomaterial Substances 0.000 description 8
- 230000001276 controlling effect Effects 0.000 description 6
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000007710 freezing Methods 0.000 description 4
- 230000008014 freezing Effects 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 238000004513 sizing Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 125000002777 acetyl group Chemical group [H]C([H])([H])C(*)=O 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 238000010557 suspension polymerization reaction Methods 0.000 description 2
- 238000004073 vulcanization Methods 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 241000251468 Actinopterygii Species 0.000 description 1
- 206010040007 Sense of oppression Diseases 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000010985 leather Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012673 precipitation polymerization Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- NMOALOSNPWTWRH-UHFFFAOYSA-N tert-butyl 7,7-dimethyloctaneperoxoate Chemical compound CC(C)(C)CCCCCC(=O)OOC(C)(C)C NMOALOSNPWTWRH-UHFFFAOYSA-N 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F114/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F114/02—Monomers containing chlorine
- C08F114/04—Monomers containing two carbon atoms
- C08F114/06—Vinyl chloride
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention relates to a production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin, which sequentially comprises the following steps of: preparing an auxiliary agent, feeding a polymerization kettle, activating materials, continuously supplementing an initiator in the middle of polymerization, discharging PVC slurry, stripping and drying; according to the invention, part of the initiator is added in a decrement manner at one time during feeding, the low-concentration high-activity initiator is continuously supplemented in the middle and later stages of the reaction, and the rate of the free radical initiation reaction is adjusted. The invention can be widely applied to the production process of special polyvinyl chloride resin for chlorination by a gas-solid phase method.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin.
Background
Chlorinated polyvinyl chloride (CPVC) is obtained by further chlorinating polyvinyl chloride (PVC), and is a novel high-molecular elastomer material between rubber and plastics. After the PVC resin is chlorinated, the irregularity of molecular bonds is increased, the polarity is enhanced, the solubility of the resin is increased, and the chemical stability is improved, so that the heat resistance, the corrosion resistance of acid, alkali, salt, an oxidant and the like of the material are improved, compared with PVC, the heat resistance, the corrosion resistance, the flame-retardant self-extinguishing property, the mechanical property and the like of CPVC are greatly improved, and the CPVC resin is widely applied to the fields of building materials, electrical, chemical engineering, metallurgy, medicine, coatings and the like.
At present, the quality of domestic CPVC resin has a large difference from that of imported resin, and one reason for the difference is that high-quality special PVC resin for chlorination is lacked in China. The development of PVC resin suitable for chlorination is a development requirement of CPVC industry and a development direction of PVC manufacturing enterprises.
The diffusion speed of chlorine molecules in PVC resin particles is an important factor for determining the chlorination reaction rate and the product quality. The diffusion of chlorine molecules in PVC resin particles can be divided into three stages from outside to inside, namely stage 1, the chlorine molecules enter the pores in the particles from the thin layer or the rupture part of the membrane of the PVC resin particles; stage 2, chlorine molecules entering the interior of the granules continuously diffuse to the deep part of the granules along the unobstructed pores in the granules and contact the surfaces of primary particles and primary particle aggregates surrounding the pores; and 3, diffusing chlorine molecules on the inner surface of the PVC resin particles into the primary particles and the aggregates. The diffusion process of chlorine gas into PVC granules puts 3 requirements on the structural characteristics of PVC resin special for chlorination: firstly, the surface of the resin particles has no or few skins, which is beneficial to the diffusion of chlorine molecules to the interior; secondly, the pores of the resin particles are uniform, and the average particle size is small; the more uniform the pore distribution, the smaller the average diameter, the larger the specific surface area within the particle, and the smaller the average depth to which chlorine gas needs to diffuse into the primary particles in stage 3; because the consumption speed of chlorine gas in the primary particles is greater than the diffusion supplement speed, the reduction of the diffusion depth is beneficial to uniform chlorination; thirdly, the primary particles and the aggregates have loose structures, the more loose the structures are, the faster the diffusion speed of chlorine molecules is, and the smaller the concentration gradient of the chlorine in the primary particles is.
Chinese invention patent CN112029137A discloses a preparation method of special PVC resin for chlorination, which comprises the following steps: adding the wet material of the water-containing PVC resin centrifuged by the PVC polymerization production system into a closed container with stirring, adding the functional organic solvent, uniformly stirring and mixing, and performing microwave heating and drying on the uniformly mixed primary material to obtain the special PVC resin for chlorination. The PVC resin wet material particles obtained by the aqueous phase polymerization method contain a large amount of water, water is changed into water vapor during microwave heating, the structure around the PVC resin particles is pressed to be closed at the initial stage of the water vapor, the constraint of the PVC resin particles and the external involucra of the particles is broken at the later stage, the PVC resin particles and the external involucra of the particles escape quickly, the special chlorination resin with loose particle structure, high plasticizer oil absorption rate and large specific surface area is obtained, the production requirement of the CPVC resin can be met, and the chlorination reaction is more favorably carried out.
The Chinese invention patent CN112029138A discloses a preparation method of polyvinyl chloride resin special for chlorination, which comprises the following steps: adding the wet material of the water-containing PVC resin centrifuged by the PVC polymerization production system into a closed container with a stirrer, adding a functional organic solvent, uniformly stirring and mixing, freezing, and carrying out microwave heating and drying on the frozen low-temperature primary material to obtain the special PVC resin for chlorination. The inside of PVC resin wet material granule that aqueous phase polymerization method obtained contains a large amount of moisture, water becomes ice to the inside aperture inflation effect of PVC resin granule when freezing, ice sublimates to vapor when microwave heating, the initial stage oppression PVC resin granule structure around closes, later stage breaks through the constraint of PVC resin granule and the outside involucra of granule, the rapid escape, it is loose to obtain the granular structure, the plasticizer oil absorption rate is high, the big special resin of chlorination of specific surface area, can satisfy the production needs of CPVC resin, more do benefit to going on of chlorination.
The above patent introduces the technology of expanding aperture by moisture expansion in the freezing aperture of wet material cake or expanding aperture by microwave heating and rapid gasification of wet material cake, or the technology of combining the freezing and icing expansion aperture and the microwave heating rapid gasification expansion aperture is adopted, the technology expands the aperture of the original PVC resin particles, improves the size and the volume of the original aperture, but does not fundamentally solve the problems of porosity abundance and uniformity, and moreover, there is a description in the prior art that in the suspension polymerization process, the pore structure is improved from the surface skin structure of the PVC resin particles by adding surfactants such as an anti-fisheye agent, a regulator, a dispersant and the like, can obviously improve and obviously change the particle morphology of the polyvinyl chloride resin on a macroscopic scale, adjust the particle size distribution and the shape roundness, the method also has better improvement on the internal gap structure, but lacks a control means on the resin deep micro-nano structure.
The CPVC resin is industrially produced by three methods: solvent method, water phase method, gas-solid phase method, wherein the gas-solid phase method is cleaner and more efficient. In the process for producing chlorinated polyvinyl chloride by a gas-solid phase method, gas-phase chlorine molecules enter through inner pore channels of particles to perform grafting reaction with PVC molecular chains, the grafting rate and the grafting uniformity are directly influenced by the abundance of pores and the uniformity of pores, meanwhile, the grafting reaction heat is removed by chlorine gas of circulating vulcanization, the polyvinyl chloride resin is produced by a suspension method process, the stirring speed of a polymerization kettle and the type and the dosage of a dispersing agent are regulated and controlled, can change the particle shape of the polyvinyl chloride resin on a macroscopic scale, adjust the particle size distribution and the shape roundness, the internal void structure is also well improved, but the regulation and control of the resin deep micro-nano structure are not easy to complete, the specificity of the PVC resin produced by the prior art on the production and application of chlorinated polyvinyl chloride is not strong, and particularly, the chlorinated polyvinyl chloride resin is difficult to remove heat by adopting a gas-solid phase chlorination process, so that the thermal stability of the chlorinated polyvinyl chloride resin is poor.
The production temperature of the low-polymerization-degree polyvinyl chloride resin is high, the thermal motion of molecules is violent, the growth rate of a polyvinyl chloride molecular chain is high, the initiation rate is reduced by controlling the quantity of free radicals required by chain initiation, generally, the concentration of the free radicals decomposed by the initial initiator is high by a process of adding the initiator at one time, the reaction rate is too high, the precipitation is too fast to form compact particles, the porosity of PVC particles is reduced, the apparent density of the PVC particles is improved, and the vulcanization of materials and the diffusion of chlorine in the gas-solid phase chlorination process are influenced.
Disclosure of Invention
In order to solve the technical problems, the invention provides a production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin, which meets the gas-solid phase chlorination process, reduces the degree of covering the surface of the special resin with a film, reduces the degree of bonding of sub-particle structures inside and outside particles, and improves the abundance and uniformity of gaps among micro-nano structures inside the particles, so that chlorine can be effectively diffused into PVC particles to generate a grafting reaction in the gas-solid phase chlorination process, and meanwhile, the reaction heat is favorably removed by outward diffusion through rich microporous structures.
The technical scheme adopted by the invention for solving the technical problems is as follows: a production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin sequentially comprises the following steps: preparing an auxiliary agent, feeding a polymerization kettle, activating materials, continuously supplementing an initiator in the middle of polymerization and discharging PVC slurry, stripping and drying;
(1) preparing an auxiliary agent: the method comprises the preparation of a dispersant A, a dispersant B, a surfactant, an initiator A, an initiator B and a neutralizing agent;
(2) feeding a polymerization kettle: spraying an anti-sticking kettle agent on the inner wall of a polymerization kettle, then completely discharging residual liquid of the kettle, starting the polymerization kettle to stir, sequentially adding cold deionized water, hot deionized water, a neutralizer, a dispersant A, a surfactant, a dispersant B, an initiator A and a vinyl chloride monomer into the polymerization kettle, and uniformly mixing the materials;
(3) material activation: continuously and constantly heating the materials in the polymerization kettle by using a polymerization kettle jacket and a hot circulating water system, and activating the materials in the polymerization kettle;
(4) continuously replenishing the initiator during the polymerization: the temperature of materials in the polymerization kettle reaches the reaction temperature of 62-68 ℃, the jacket hot water is switched to the circulating cooling water, the reaction temperature of the polymerization kettle is controlled, the reaction lasts for 60-90 min, and the initiator B is continuously supplemented to the set formula amount; the method is characterized in that the polyvinyl chloride resin with medium and low polymerization degrees is produced by a high-temperature method, the amount of initiator is large after one-time investment, the concentration of initiator decomposed free radicals at the initial stage is too high, the initiation rate is high, the volume shrinkage caused by phase change in vinyl chloride liquid drops reduces the pore density in PVC particles, part of initiator is added in a one-time decrement manner during feeding, the initiator with low concentration and high activity is continuously supplemented at the middle and later stages of reaction, and the rate of free radical initiation reaction is adjusted;
(5) the PVC slurry is discharged, stripped and dried to obtain the PVC resin with the average polymerization degree of 650-850.
The production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin comprises the following steps: dissolving polyvinyl alcohol with alcoholysis degree of 65-75% into 3-5% solution for later use; preparation of the dispersant B: hydroxypropyl methylcellulose is prepared into 3 to 5 percent solution for standby.
The production method of the special low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride resin comprises the following steps of: the polyvinyl alcohol solution with alcoholysis degree of 35-50% and block distribution is prepared for standby. The polyvinyl alcohol with 35-50% of low alcoholysis degree block distribution is selected, more acetyl groups and less hydroxyl blocks are distributed on a molecular chain segment of PVA, the acetyl groups have good lipophilicity and can quickly adsorb the surface of a monomer liquid drop and even be dissolved in the monomer, the hydroxyl groups have oleophobic property, if the polyvinyl chloride with low alcoholysis degree can be dissolved in the monomer liquid drop, the oleophobic hydroxyl groups in the liquid drop can continuously form obstruction in the liquid drop, the cohesion among the conglomerates is weakened in the polymer forming process, and the internal pore volume of PVC particles is adjusted.
The production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin comprises the following steps: peroxide 3,5, 5-trimethylhexanoyl, initiator B: cumene peroxyneodecanoate is prepared into 0.5 to 1 percent solution; the neutralizer is prepared by preparing 3-5% solution of carbonate for later use. In vinyl chloride polymerization, the type and amount of the initiator have very important influences on the polymerization reaction rate, the reaction process control and the product quality of the finally synthesized polyvinyl chloride resin. The initiator has high activity, fast reaction rate, low activity and relatively slow reaction. The selection and the dosage of the initiator have certain relation with whether the equipment can remove the reaction heat in time or not and reasonably control the reaction process. In production, a high-low activity matching and composite initiator combination is often selected to control the vinyl chloride polymerization process. The special resin for chloroethylene by the gas-solid phase method is cumyl peroxyneodecanoate and tert-butyl peroxyneodecanoate, and the two initiators are compounded to be suitable for the industrial production of low-polymerization-degree resin and also accord with the production process method provided by the application.
The production method of the special low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride resin comprises the step of adding vinyl chloride monomers into a polymerization kettle, wherein the vinyl chloride monomers comprise recycled vinyl chloride monomers and fresh vinyl chloride monomers.
According to the production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin, the material temperature of cold deionized water and hot deionized water is adjusted to be 32-36 ℃ according to the proportion; the neutralizing agent is used for adjusting the pH value of the material to 6.5-8.0.
In the production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin, the circulating water temperature is controlled at 80-85 ℃ in the material activation process, and the constant temperature rise rate is 0.5-2.0 ℃/min. Vinyl chloride polymerization is a free radical chain polymerization. The extent of free radical formation controls the rate of strand initiation. After chain initiation, vinyl chloride chain growth occurs. After the free radical of the PVC chain grows to a certain degree, the free radical tends to precipitate. After continuing to grow into the original particles, the precipitate is easily re-precipitated. The reaction is difficult or even impossible to initiate at very low temperature growth rates. At too fast a temperature growth rate, the rate of initiator decomposition into free radicals increases and the rate of molecular collision chain growth also increases. When a large number of primary particles are formed simultaneously, the system becomes extremely viscous and unstable. When the rapid sedimentation is carried out, the adhesive is easy to adhere to form a whole body to close the pore channel. By controlling the heating rate, the materials are slowly and stably activated, the initial reaction rate is properly adjusted, the original particle forming rate is controlled, and the polyvinyl chloride resin is slowly precipitated. When the primary particles form primary particle cores, the primary particles continue to grow into primary particles, and the primary particles grow up and are flocculated into agglomerates again. In order to avoid the concentration of the formation stage of the micro-nano structure, the low-temperature activation treatment is adopted to regulate and control the chain initiation and chain growth rate, reduce the bonding of original particles and reduce the aggregation degree of primary particles in an unstable period, thereby achieving the purpose of regulating and controlling the micro-nano structure of the PVC resin particles.
The production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin comprises the steps of adding the initiator A in one step in the feeding process of a polymerization kettle, supplementing the initiator B in the middle of polymerization, controlling the supplementing flow of the initiator B by a flow-limiting orifice plate to be 80-120kg/h, mixing with water injected in the middle of polymerization, and controlling the temperature of the water injected in the middle of polymerization to be 7-10 ℃. In the polymerization reaction process, in a certain area, the activity of the initiator is high, or the local concentration of the initiator is too high, the polymerization reaction rate of vinyl chloride can cause uneven conditions, more 'fish eyes' are easily formed in the initial reaction stage, or compact particles are formed, so that the pore structure of a resin product is poor, and the resin product is not easily used in the chlorination process. If the initiator can be continuously dripped, the concentration of the initiator in a polymerization system, the concentration of free radicals and the reaction rate are uniformly and stably controlled, so that the reaction is stable.
The production method of the low polymerization degree gas-solid phase chlorinated polyvinyl chloride special resin has the advantages that the polymerization temperature is controlled within the range of 62-65 ℃, and a polyvinyl chloride product with the average polymerization degree of 800 +/-50 is obtained; the polymerization temperature is controlled within the range of 65-68 ℃, and the polyvinyl chloride product with the average polymerization degree of 700 +/-50 is obtained.
The production method of the special low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride resin has the advantage that the fluctuation deviation of the reaction temperature of a polymerization kettle is controlled to be +/-0.5 ℃ in the polymerization reaction control process.
The production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin comprises the following steps of discharging, stripping and drying the PVC slurry: after 4.5-6h of polymerization reaction, when the reaction pressure of the polymerization kettle is reduced to-0.05 MPa to-0.07 MPa, adding a terminator into the polymerization kettle after the polymerization reaction is finished, discharging PVC slurry, recovering unreacted vinyl chloride monomer, removing PVC and residual monomer in water from the PVC slurry through steam stripping, removing mother liquor in the slurry, and drying a material cake to obtain a finished product PVC resin with the average polymerization degree of 650-850; the specific surface area of the PVC resin is 2-5m2/g。
The percentages referred to in the invention are mass percentages.
Compared with the prior art, the invention provides a production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin, which is characterized in that part of initiator is added in a decrement manner at one time when materials are fed, the low-concentration high-activity initiator is continuously supplemented in the middle and later stages of the reaction, and the rate of the free radical initiation reaction is adjusted; by selecting a surfactant with a block distribution structure, a protection structure is formed inside and outside a vinyl chloride monomer liquid drop by a special group possessed by the surfactant, so that the sub-particle structure adhesion degree inside and outside particles is reduced; the growth process of PVC from primary particles to aggregates is adjusted by controlling the chemical reaction kinetics, so that the aggregation density of primary particles is reduced, the strength of flocculated primary particles is improved, the adhesion degree of the flocculated primary particles when the flocculated primary particles form the aggregates is reduced, and more uniform pores are formed among micro-nano structures such as PVC aggregates;
the invention overcomes the defects that the initiator with medium and low activity is added into a reaction kettle at one time in the traditional process and is decomposed into radicals with high effective concentration and over-high initial initiation rate after being activated, so that the internal original particle structure is over-fast precipitated and coalesced, the internal porosity is lower and uneven, the invention intervenes in the PVC particle synthesis stage, regulates the particle structure form by dispersing agent and stirring in the macroscopic view, controls the precipitation polymerization rate of the micro-nano structure to regulate the micro-nano structure in the microscopic view, and synchronously carries out the two processes, thereby reducing the consumption of dispersing agent in suspension polymerization, and reducing the formation of the leather membrane structure by PVC resinThe method overcomes the problem of insufficient abundance and uniformity of pores in the production of PVC resin by a common suspension method, increases the diffusion capacity of the special resin to small molecular substances, and facilitates the chlorine to enter the deep inside of the particles to diffuse deeply and carry out chlorination reaction to the deep inside of the particles during chlorination grafting reaction. In the production of low-polymerization-degree resin by high-temperature polymerization, the low-concentration high-activity initiator is used for replacing the high-concentration low-activity initiator, so that the reaction acceleration out of control caused by the treatment after the initiator residue is polymerized is reduced, and the BET specific surface area of the PVC resin prepared by the invention can reach 2-5m2The BET specific surface area of the PVC resin produced by the original process is 0.4-0.8m2(ii) in terms of/g. The invention can be widely applied to the production process of special polyvinyl chloride resin for chlorination by a gas-solid phase method.
Detailed Description
A production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin sequentially comprises the following steps:
preparing an auxiliary agent, feeding a polymerization kettle, activating materials, continuously supplementing an initiator in the middle of polymerization and discharging PVC slurry, stripping and drying;
(1) preparing an auxiliary agent: the method comprises the preparation of a dispersant A, a dispersant B, a surfactant, an initiator A, an initiator B and a neutralizing agent;
(2) feeding a polymerization kettle: spraying an anti-sticking kettle agent on the inner wall of a polymerization kettle, then completely discharging residual liquid of the kettle, starting the polymerization kettle to stir, sequentially adding cold deionized water, hot deionized water, a neutralizer, a dispersant A, a surfactant, a dispersant B, an initiator A and a vinyl chloride monomer into the polymerization kettle, and uniformly mixing the materials;
(3) material activation: continuously and constantly heating the materials in the polymerization kettle by using a polymerization kettle jacket and a hot circulating water system, and activating the materials in the polymerization kettle;
(4) continuously replenishing the initiator during the polymerization: the temperature of materials in the polymerization kettle reaches the reaction temperature of 62 ℃, the jacket hot water is switched to the circulating cooling water, the reaction temperature of the polymerization kettle is controlled, the reaction is carried out for 60min, and the initiator B is continuously supplemented to the set formula amount; the method is characterized in that the polyvinyl chloride resin with medium and low polymerization degrees is produced by a high-temperature method, the amount of initiator is large after one-time investment, the concentration of initiator decomposed free radicals at the initial stage is too high, the initiation rate is high, the volume shrinkage caused by phase change in vinyl chloride liquid drops reduces the pore density in PVC particles, part of initiator is added in a one-time decrement manner during feeding, the initiator with low concentration and high activity is continuously supplemented at the middle and later stages of reaction, and the rate of free radical initiation reaction is adjusted;
(5) the PVC slurry is discharged, stripped and dried to obtain the PVC resin with the average polymerization degree of 650-850.
Another example is different in that the temperature of the material in the polymerization vessel reached the reaction temperature of 68 ℃ and the jacket hot water was switched to the circulating cooling water to control the reaction temperature of the polymerization vessel for 90 min.
Another example is different in that the temperature of the material in the polymerization vessel reached 65 ℃ reaction temperature, the jacket hot water was switched to the circulating cooling water, and the polymerization vessel reaction temperature was controlled for 70 min.
Another example differs in that its preparation of the dispersant a: dissolving polyvinyl alcohol with alcoholysis degree of 65% into 3% solution for later use; preparation of the dispersant B: hydroxypropyl methylcellulose was formulated into a 3% solution for use.
Another example differs in that its preparation of the dispersant a: dissolving polyvinyl alcohol with alcoholysis degree of 75% into 5% solution for later use; preparation of the dispersant B: hydroxypropyl methylcellulose is prepared into a 5% solution for later use.
Another example differs in that its preparation of the dispersant a: dissolving polyvinyl alcohol with alcoholysis degree of 70% into 3% solution for later use; preparation of the dispersant B: hydroxypropyl methylcellulose is prepared into a 5% solution for later use.
Another example differs in that its preparation of the surfactant: a polyvinyl alcohol solution having an alcoholysis degree of 35% and being distributed in blocks was prepared.
Another example differs in that its preparation of the surfactant: a polyvinyl alcohol solution having an alcoholysis degree of 50% and being distributed in blocks was prepared.
Another example differs in that its preparation of the surfactant: a polyvinyl alcohol solution with alcoholysis degree of 40% and block distribution is prepared.
Another embodiment differs in that the initiator comprises initiator a: peroxide 3,5, 5-trimethylhexanoyl, initiator B: cumene peroxyneodecanoate was formulated as a 0.5% solution; the neutralizer is prepared by preparing carbonate into 3% solution for later use.
Another embodiment differs in that the initiator comprises initiator a: peroxide 3,5, 5-trimethylhexanoyl, initiator B: cumene peroxyneodecanoate is prepared into a 1% solution; the neutralizer is prepared by carbonate to prepare 5% solution for later use.
Another embodiment differs in that the initiator comprises initiator a: peroxide 3,5, 5-trimethylhexanoyl, initiator B: cumene peroxyneodecanoate was formulated as a 0.8% solution; the neutralizer is prepared by carbonate to prepare 4% solution for later use.
Another embodiment is different in that the vinyl chloride monomer added to the polymerizer includes recycled vinyl chloride monomer and fresh vinyl chloride monomer.
The difference of another embodiment is that the cold deionized water and the hot deionized water are proportionally adjusted to the material temperature controlled at 32 ℃; the neutralizing agent adjusts the pH value of the material to 8.0.
The difference of another embodiment is that the cold deionized water and the hot deionized water are proportionally adjusted to the material temperature controlled at 36 ℃; the neutralizing agent adjusts the pH value of the material to 6.5.
The difference of another embodiment is that the cold deionized water and the hot deionized water are proportionally adjusted to the material temperature controlled at 35 ℃; the neutralizing agent adjusts the pH value of the material to 7.0.
Another embodiment is different in that in the material activation process, the circulating water temperature is controlled at 80 ℃, and the constant heating rate is 0.5 ℃/min.
Another embodiment is different in that the temperature of circulating water is controlled at 85 ℃ in the material activation process, and the constant temperature rising rate is 2.0 ℃/min.
Another embodiment is different in that in the material activation process, the temperature of circulating water is controlled at 82 ℃, and the constant heating rate is 1.2 ℃/min.
The difference of another embodiment is that the initiator A is added at one time in the feeding process of the polymerization kettle, the initiator B is replenished in the middle of polymerization, the replenishing flow of the initiator B is controlled by a flow-limiting orifice plate to be 80kg/h, the initiator B is mixed with water injected in the middle, and the temperature of the water injected in the middle is controlled to be 7 ℃.
The difference of another embodiment is that the initiator A is added at one time in the feeding process of the polymerization kettle, the initiator B is replenished in the middle of polymerization, the replenishing flow rate of the initiator B is controlled by a flow-limiting orifice plate to be 120kg/h, the initiator B is mixed with water injected in the middle, and the temperature of the water injected in the middle is controlled to be 8 ℃.
The difference of another embodiment is that the initiator A is added at one time in the feeding process of the polymerization kettle, the initiator B is replenished in the middle of polymerization, the replenishing flow rate of the initiator B is controlled by a flow-limiting orifice plate to be 100kg/h, the initiator B is mixed with water injected in the middle, and the temperature of the water injected in the middle is controlled to be 10 ℃.
The difference of another embodiment is that the polymerization temperature is controlled within 62 ℃ to obtain a polyvinyl chloride product with the average polymerization degree of 800 +/-50; the polymerization temperature is controlled within 66 ℃, and the polyvinyl chloride product with the average polymerization degree of 700 +/-50 is obtained.
The other embodiment is different in that the polymerization temperature is controlled within 64 ℃ to obtain a polyvinyl chloride product with the average polymerization degree of 800 +/-50; the polymerization temperature is controlled within 68 ℃ to obtain the polyvinyl chloride product with the average polymerization degree of 700 +/-50.
The difference of another embodiment is that the discharging, steam stripping and drying processes of the PVC sizing agent are as follows: after 4.5 of polymerization reaction, when the reaction pressure drop of the polymerization kettle reaches-0.05 MPa, adding a terminator into the polymerization kettle after the polymerization reaction is finished, discharging PVC slurry and recovering unreacted vinyl chloride monomers, removing PVC and residual monomers in water from the PVC slurry through steam stripping, then removing mother liquor from the slurry, and drying the material cake to obtain the finished product PVC resin with the average polymerization degree of 650-850; the specific surface area of the PVC resin is 2 m2/g。
The difference of another embodiment is that the discharging, steam stripping and drying processes of the PVC sizing agent are as follows: after the polymerization reaction is carried out for 6 hours, when the reaction pressure of the polymerization kettle is reduced to reachWhen the pressure is-0.07 MPa, adding a terminator into the polymerization kettle after the polymerization reaction is finished, discharging PVC slurry, recovering unreacted vinyl chloride monomer, removing PVC and residual monomer in water from the PVC slurry through steam stripping, removing mother liquor in the slurry, and drying a material cake to obtain a finished product PVC resin with the average polymerization degree of 650-850; the specific surface area of the PVC resin is 5m2/g。
The difference of another embodiment is that the discharging, steam stripping and drying processes of the PVC sizing agent are as follows: after 5 hours of polymerization reaction, when the reaction pressure drop of the polymerization kettle reaches-0.06 MPa, adding a terminator into the polymerization kettle after the polymerization reaction is finished, discharging PVC slurry and recovering unreacted vinyl chloride monomers, removing PVC and residual monomers in water from the PVC slurry through steam stripping, then removing mother liquor from the slurry, and drying a material cake to obtain a finished product PVC resin with the average polymerization degree of 650-850; the specific surface area of the PVC resin is 4 m2/g。
Claims (10)
1. The production method of the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin is characterized by sequentially comprising the following steps of: preparing an auxiliary agent, feeding a polymerization kettle, activating materials, continuously supplementing an initiator in the middle of polymerization and discharging PVC slurry, stripping and drying;
(1) preparing an auxiliary agent: the method comprises the preparation of a dispersant A, a dispersant B, a surfactant, an initiator A, an initiator B and a neutralizing agent;
(2) feeding a polymerization kettle: spraying an anti-sticking kettle agent on the inner wall of a polymerization kettle, then completely discharging residual liquid of the kettle, starting the polymerization kettle to stir, sequentially adding cold deionized water, hot deionized water, a neutralizer, a dispersant A, a surfactant, a dispersant B, an initiator A and a vinyl chloride monomer into the polymerization kettle, and uniformly mixing the materials;
(3) material activation: continuously and constantly heating the materials in the polymerization kettle by using a polymerization kettle jacket and a hot circulating water system, and activating the materials in the polymerization kettle;
(4) continuously replenishing the initiator during the polymerization: the temperature of materials in the polymerization kettle reaches the reaction temperature of 62-68 ℃, the jacket hot water is switched to the circulating cooling water, the reaction temperature of the polymerization kettle is controlled, the reaction lasts for 60-90 min, and the initiator B is continuously supplemented to the set formula amount;
(5) the PVC slurry is discharged, stripped and dried to obtain the PVC resin with the average polymerization degree of 650-850.
2. The method for producing the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 1, wherein the preparation of the dispersant A comprises the following steps: dissolving polyvinyl alcohol with alcoholysis degree of 65-75% into 3-5% solution for later use; preparation of the dispersant B: hydroxypropyl methylcellulose is prepared into 3 to 5 percent solution for standby.
3. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 2, wherein the preparation of the surfactant comprises the following steps: the polyvinyl alcohol solution with alcoholysis degree of 35-50% and block distribution is prepared for standby.
4. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 3, wherein the initiator comprises initiator A: peroxide 3,5, 5-trimethylhexanoyl, initiator B: cumene peroxyneodecanoate is prepared into 0.5 to 1 percent solution; the neutralizer is prepared by preparing 3-5% solution of carbonate for later use.
5. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 4, wherein the method comprises the following steps: the vinyl chloride monomer added into the polymerization kettle comprises recycled vinyl chloride monomer and fresh vinyl chloride monomer.
6. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 5, wherein the method comprises the following steps: the cold deionized water and the hot deionized water are proportionally adjusted to the material temperature of 32-36 ℃; the neutralizing agent is used for adjusting the pH value of the material to 6.5-8.0.
7. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 6, wherein the method comprises the following steps: in the material activation process, the temperature of circulating water is controlled to be 80-85 ℃, and the constant temperature rise rate is 0.5-2.0 ℃/min.
8. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 1 or 4, wherein: the initiator A is added at one time in the feeding process of the polymerization kettle, the initiator B is replenished in the middle of polymerization, the replenishing flow of the initiator B is controlled by a flow-limiting orifice plate to be 80-120kg/h, the initiator B is mixed with water injected in the middle, and the temperature of the water injected in the middle is controlled to be 7-10 ℃.
9. The method for producing a low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin according to claim 1, characterized in that: the polymerization temperature is controlled within the range of 62-65 ℃, and a polyvinyl chloride product with the average polymerization degree of 800 +/-50 is obtained; the polymerization temperature is controlled within the range of 65-68 ℃, and the polyvinyl chloride product with the average polymerization degree of 700 +/-50 is obtained.
10. The method for producing the low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin as claimed in any one of claims 1 to 9, wherein the discharging, stripping and drying processes of the PVC slurry comprise the following steps: after 4.5-6h of polymerization reaction, when the reaction pressure of the polymerization kettle is reduced to-0.05 MPa to-0.07 MPa, adding a terminator into the polymerization kettle after the polymerization reaction is finished, discharging PVC slurry, recovering unreacted vinyl chloride monomer, removing PVC and residual monomer in water from the PVC slurry through steam stripping, removing mother liquor in the slurry, and drying a material cake to obtain a finished product PVC resin with the average polymerization degree of 650-850; the specific surface area of the PVC resin is 2-5m2/g。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110716419.7A CN113461844A (en) | 2021-06-28 | 2021-06-28 | Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110716419.7A CN113461844A (en) | 2021-06-28 | 2021-06-28 | Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113461844A true CN113461844A (en) | 2021-10-01 |
Family
ID=77873153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110716419.7A Pending CN113461844A (en) | 2021-06-28 | 2021-06-28 | Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113461844A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1135607A (en) * | 1997-05-20 | 1999-02-09 | Tokuyama Sekisui Ind Corp | Production of vinyl chloride-based resin |
| CN1446830A (en) * | 2003-04-04 | 2003-10-08 | 上海氯碱化工股份有限公司 | Method for producing PVC with low degree of polymerization |
| JP2006104485A (en) * | 1997-07-31 | 2006-04-20 | Tokuyama Sekisui Ind Corp | Method for producing chlorinated vinyl chloride resin |
| CN104371047A (en) * | 2014-11-12 | 2015-02-25 | 天伟化工有限公司 | Method for spraying antisticking agent of vinyl chloride polymerization kettle |
| CN105218713A (en) * | 2014-05-27 | 2016-01-06 | 中国石油化工集团公司 | A kind of polyvinyl alcohol and its production and use |
| CN105801732A (en) * | 2014-12-31 | 2016-07-27 | 青岛威德森贸易有限公司 | Polyvinyl chloride suspension polymerization preparation method and feeding device |
| CN108192001A (en) * | 2017-12-26 | 2018-06-22 | 新疆兵团现代绿色氯碱化工工程研究中心(有限公司) | A kind of preparation method of polyvinyl chloride resin used for chlorination |
-
2021
- 2021-06-28 CN CN202110716419.7A patent/CN113461844A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1135607A (en) * | 1997-05-20 | 1999-02-09 | Tokuyama Sekisui Ind Corp | Production of vinyl chloride-based resin |
| JP2006104485A (en) * | 1997-07-31 | 2006-04-20 | Tokuyama Sekisui Ind Corp | Method for producing chlorinated vinyl chloride resin |
| CN1446830A (en) * | 2003-04-04 | 2003-10-08 | 上海氯碱化工股份有限公司 | Method for producing PVC with low degree of polymerization |
| CN105218713A (en) * | 2014-05-27 | 2016-01-06 | 中国石油化工集团公司 | A kind of polyvinyl alcohol and its production and use |
| CN104371047A (en) * | 2014-11-12 | 2015-02-25 | 天伟化工有限公司 | Method for spraying antisticking agent of vinyl chloride polymerization kettle |
| CN105801732A (en) * | 2014-12-31 | 2016-07-27 | 青岛威德森贸易有限公司 | Polyvinyl chloride suspension polymerization preparation method and feeding device |
| CN108192001A (en) * | 2017-12-26 | 2018-06-22 | 新疆兵团现代绿色氯碱化工工程研究中心(有限公司) | A kind of preparation method of polyvinyl chloride resin used for chlorination |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20150361236A1 (en) | Bead polymer for producing pmi foams | |
| KR20080018082A (en) | Methods of preparing a vinyl chloride polymer having superior workability | |
| CN112678779B (en) | Preparation method of ammonium persulfate crystal | |
| US11084782B2 (en) | Gas generating agent, and method for producing foam using the same | |
| CN113388055B (en) | Low-polymerization-degree polyvinyl chloride special resin | |
| CN113461844A (en) | Production method of low-polymerization-degree gas-solid phase chlorinated polyvinyl chloride special resin | |
| CN113292665A (en) | Special resin for polyvinyl chloride with medium and high polymerization degrees | |
| CN113388056A (en) | Production method of special resin for gas-solid phase chlorinated polyvinyl chloride with medium and high polymerization degrees | |
| EP0240983A2 (en) | Compacted agglomerates of polymer latex particles | |
| CN113354760A (en) | Method for regulating and controlling micro-nano structure of polyvinyl chloride resin particles | |
| US3425966A (en) | Three stage suspension polymerization process for vinyl aryl monomers | |
| US20240010809A1 (en) | Nanocellular expanded polymer beads, method of manufacture and uses | |
| US4732953A (en) | Novel polyvinyl chloride suspension polymerization process and product having improved plasticizer absorption | |
| CN109415453B (en) | Process for producing vinyl chloride polymer | |
| CN114751869A (en) | Preparation method of high-dispersion melamine cyanurate flame retardant | |
| CN114437397A (en) | Foaming device of foaming beads, production method and application thereof, and foaming beads | |
| CN1064373C (en) | Method for manufacturing polystyrene type beads and expandable polystyrene type beads | |
| CN113831429A (en) | Coagulation washing method of peroxide vulcanized fluororubber emulsion for extrusion | |
| CN112390236A (en) | Production method of acid potassium dihydrogen phosphate | |
| CA1250085A (en) | Polyvinyl chloride suspension polymerization process and product | |
| CN117510690A (en) | Low-density small-particle-size hollow polymer microsphere and preparation method and application thereof | |
| CN118255915A (en) | PVC resin special for preparing CPVC and preparation method thereof | |
| JPS6389418A (en) | Production of spherical-shaped porous basic magnesium carbonate | |
| US2974129A (en) | Process for preparing polyvinyl chloride useful in plastisols | |
| US3879363A (en) | Polymerisation process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211001 |
|
| RJ01 | Rejection of invention patent application after publication |