CN109651542B - Modified polyvinyl alcohol dispersant, preparation method and application thereof - Google Patents
Modified polyvinyl alcohol dispersant, preparation method and application thereof Download PDFInfo
- Publication number
- CN109651542B CN109651542B CN201710941586.5A CN201710941586A CN109651542B CN 109651542 B CN109651542 B CN 109651542B CN 201710941586 A CN201710941586 A CN 201710941586A CN 109651542 B CN109651542 B CN 109651542B
- Authority
- CN
- China
- Prior art keywords
- polyvinyl alcohol
- modified polyvinyl
- polymerization
- methanol
- reaction
- 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.)
- Active
Links
Images
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
- C08F8/00—Chemical modification by after-treatment
- C08F8/12—Hydrolysis
-
- 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
-
- 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
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/20—Aqueous medium with the aid of macromolecular dispersing agents
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention provides a modified polyvinyl alcohol dispersing agent, which is prepared by modifying polyvinyl alcohol by using valeraldehyde, wherein the appearance of the prepared modified polyvinyl alcohol is light yellow powder, the polymerization degree is 500-1000, the alcoholysis degree is 68-78% (mol/mol), the viscosity of a 4% aqueous solution is 4.0-8.0mpa.s, and the modified polyvinyl alcohol dispersing agent has good dispersing effect, can effectively inhibit foaming in the vinyl chloride polymerization process and has good adhesive retention performance and dispersing performance when being used as a main dispersing agent for vinyl chloride suspension polymerization. The preparation method is simple, short in process time, free of large-scale equipment and suitable for industrial production.
Description
Technical Field
The invention relates to a polyvinyl alcohol dispersing agent, in particular to a modified polyvinyl alcohol dispersing agent, and a preparation method and application thereof.
Background
Polyvinyl alcohol (PVA) is used as the most commonly used dispersing agent for vinyl chloride suspension polymerization, and plays a vital role in the performance indexes of vinyl chloride suspension polymerization and polyvinyl chloride products. However, with the use of large polymerization reactors equipped with a condenser in the vinyl chloride industry, the pressure in the vicinity of the reflux condenser drops due to condensation of the vinyl chloride monomer vapor, thereby generating wet foam caused by the dispersant and dry foam consisting of PVC particles, resulting in a reduction in the effective volume in the polymerization vessel, a decrease in production efficiency, and also fouling. Therefore, it is necessary to develop a novel polyvinyl alcohol as a dispersant.
In the research of developing novel polyvinyl alcohol dispersing agents, a large amount of research is carried out by experts at home and abroad. Chinese patent CN151927A discloses that polyvinyl alcohol resin is melt kneaded in an extruder at the temperature of 175-250 ℃ for 1-15 minutes by adding assistants such as metal salt to prepare a modified polyvinyl alcohol dispersing agent; in the method, the modified polyvinyl alcohol can generate serious dehydration and decarboxylation reaction and partial decomposition reaction, so the method has high economic cost, and the prepared product has darker color, generates insoluble substances and has poorer product quality. Chinese patent CN101747459A discloses that a modified polyvinyl alcohol dispersant is prepared by polymerizing for 8-14h in a bulk polymerization or solution polymerization mode and then carrying out subsequent processes of alcoholysis, drying and the like; the method has long polymerization time, the molecular weight distribution of the product is too wide, and the prepared product has poor foam inhibition performance; meanwhile, the modified polyvinyl alcohol product prepared by the method is only used as an auxiliary dispersant in vinyl chloride suspension polymerization. Due to the great technical difficulty, at present, no polyvinyl alcohol which has good product color phase and excellent foam inhibition, gel retention and dispersibility and a preparation technology thereof are disclosed as a dispersing agent.
Disclosure of Invention
In order to solve the problems of the prior art, according to a first aspect of the present invention, there is provided a modified polyvinyl alcohol.
Except for special description, the parts are parts by weight, and the percentages are mass percentages.
The purpose of the invention is realized as follows:
the modified polyvinyl alcohol is prepared from raw materials including methanol, Vinyl Acetate (VAC) monomer, valeraldehyde and initiator, and is characterized in that: the ultraviolet absorption value of the modified polyvinyl alcohol at 215nm is 0.1-0.7, the ultraviolet absorption value at 280nm is 0.2-0.7, and the ultraviolet absorption value at 320nm is 0.05-0.5.
The valeraldehyde is also called n-valeraldehyde and has the chemical formula C5H10And O. 1730-1740cm in FTIR spectrogram of modified polyvinyl alcohol-1Has strong placeA strong carbonyl absorption peak.
The modified polyvinyl alcohol of the invention simultaneously has a structure of-CO-CH (CH-CH) -and-CO- (CH-CH)2-structure, and-CO- (CH ═ CH)3-a structure. Wherein, the modified polyvinyl alcohol has an ultraviolet absorption peak with a structure of-CO-CH (CH) at 215nm and-CO- (CH) at 280nm2UV absorption peak of structure-CO- (CH ═ CH) at 320nm3-ultraviolet absorption peak of the structure.
In the experiment for researching the polyvinyl alcohol dispersant, the inventor unexpectedly found that the ultraviolet absorption value at 215nm prepared by using methanol, Vinyl Acetate (VAC) monomer and valeraldehyde under the action of an initiator is 0.1-0.7, the ultraviolet absorption value at 280nm is 0.2-0.7,320nm is 0.05-0.5, and an FTIR spectrum is 1730-1740cm-1The modified polyvinyl alcohol with a strong carbonyl absorption peak has good dispersion effect, can effectively inhibit foaming in the vinyl chloride polymerization process, and has good adhesive retention performance and dispersion performance when being used as a vinyl chloride suspension polymerization dispersing agent.
The polymerization degree of the modified polyvinyl alcohol is 500-1000, and the alcoholysis degree is 65-78% (mol/mol). The viscosity of the modified polyvinyl alcohol 4% aqueous solution is 4.0-8.0 mpa.s.
The initiator is one or a combination of more of azobisisobutyronitrile, azobisisoheptonitrile, bis (4-tert-butylcyclohexyl) peroxydicarbonate, pivalic acid-tert-amyl peroxypivalate, bis (2-ethylhexyl) peroxydicarbonate, bis (3,5, 5-trimethylhexanoyl) peroxide, dipropyl peroxydicarbonate, potassium persulfate, ammonium persulfate, sodium bisulfite, sodium bicarbonate, tartaric acid or rongalite.
The dosage of the methanol, the Vinyl Acetate (VAC) monomer, the valeraldehyde and the initiator is as follows: 20-100 parts of methanol, 100 parts of Vinyl Acetate (VAC), 2.5-7.5 parts of valeraldehyde and 0.015-0.175 part of initiator.
According to a second aspect of the present invention, it is an object of the present invention to provide a method for producing a modified polyvinyl alcohol.
The preparation method of the modified polyvinyl alcohol comprises the steps of polymerization, hydrolysis, solid-liquid separation and drying, and is characterized in that: the polymerization step is that methanol, Vinyl Acetate (VAC) monomer, valeraldehyde and initiator are added into a reaction kettle, and polymerization reaction is carried out for 3-5 hours at the temperature of 60-65 ℃ to prepare polyvinyl acetate methanol solution.
The hydrolysis is to adjust the concentration of the polyvinyl acetate methanol solution to 8-30 percent (the concentration refers to the concentration of polyvinyl acetate in the methanol solution), keep the temperature at 25-50 ℃ for 1-2 hours, then add sodium hydroxide methanol solution to carry out hydrolysis reaction for 5-120 minutes, and add glacial acetic acid to stop the reaction after the reaction is finished.
The alcoholysis catalyst is sodium hydroxide methanol solution, and the dosage of the alcoholysis catalyst is 0.005-0.10 (molar ratio) of the resin in the alcoholysis solution; the alcoholysis terminator is glacial acetic acid, the dosage of which is the same as that of the alcoholysis catalyst and is 0.005-0.10 (molar ratio) of the resin in the alcoholysis solution.
The drying is to dry the separated solid part in a vacuum drier, the drying temperature is 70-150 ℃, the vacuum degree is-0.03 to-0.01 MPa, and the drying time is 2-4 hours.
Specifically, the preparation method of the modified polyvinyl alcohol dispersant comprises the steps of polymerization, hydrolysis, solid-liquid separation and drying, and is characterized in that: the polymerization is that methanol, Vinyl Acetate (VAC) monomer, valeraldehyde and initiator are added into a polymerization kettle with stirring at normal pressure; after the addition is finished, reacting for 3-5 hours at 60-65 ℃; after the reaction is finished, heating up for evaporation and recovering residual monomers to obtain concentrated polyvinyl acetate methanol solution.
The hydrolysis is to adjust the concentration of a polyvinyl acetate methanol solution to 10-30 percent (the concentration refers to the concentration of polyvinyl acetate in the methanol solution), keep the temperature at 35-50 ℃ for 1-2 hours, then add a sodium hydroxide methanol solution (the concentration of the sodium hydroxide solution is 25-100g/l) to carry out hydrolysis reaction for 5-120 minutes, and add glacial acetic acid to stop the reaction after the reaction is finished; obtaining pure white polyvinyl alcohol methanol solid-liquid mixture.
And the solid-liquid separation is to uniformly send the hydrolyzed polyvinyl alcohol methanol solid-liquid mixture into a centrifugal machine protected by nitrogen for solid-liquid separation.
The drying is to dry the separated solid part in a vacuum drier, the drying temperature is 70-150 ℃, the vacuum degree is-0.03 to-0.01 MPa, and the drying time is 2-4 hours.
According to a third aspect of the present invention, it is an object of the present invention to provide use of the above-mentioned modified polyvinyl alcohol as a dispersing agent for suspension polymerization of vinyl chloride; in particular for use as a primary dispersing agent for vinyl chloride suspension polymerization.
Advantageous effects
The invention uses valeraldehyde to modify polyvinyl alcohol, the ultraviolet absorption value of the prepared modified polyvinyl alcohol at 215nm is 0.1-0.7, the ultraviolet absorption value at 280nm is 0.2-0.7,320nm is 0.05-0.5, and the FTIR spectrogram is 1730--1Has strong carbonyl absorption peak, has good dispersion effect, can effectively inhibit foaming in the polymerization process of the chloroethylene, and has good adhesive retention performance and dispersion performance when being used as a chloroethylene suspension polymerization dispersing agent. The modified polyvinyl alcohol is light yellow powder, the polymerization degree is 500-1000, the alcoholysis degree is 68-78% (mol/mol), and the viscosity of a 4% aqueous solution is 4.0-8.0 mpa.s. The modified polyvinyl alcohol is used as a dispersing agent for vinyl chloride suspension polymerization, particularly as a main dispersing agent for vinyl chloride suspension polymerization, has good dispersing effect, can effectively inhibit foaming in the vinyl chloride polymerization process, and has good adhesive retention performance and dispersing performance; can prepare a polyvinyl chloride product with viscosity number of 107-112ml/g, apparent density of 0.45-0.50g/ml, plasticizer absorption of more than 20 percent, excellent performance and uniform particle size distribution. The preparation method is simple, short in process time, free of large-scale equipment and suitable for industrial production.
Drawings
FIG. 1 is an infrared spectrum of a modified polyvinyl alcohol of the present invention;
FIG. 2 is an NMR spectrum of a sample of modified polyvinyl alcohol of the invention;
FIG. 3 is a scanning electron microscope image of a PVC resin prepared using the modified polyvinyl alcohol dispersant of example 1 of the present invention; in FIGS. 1 and 2 of the present invention, 1# is the modified polyvinyl alcohol prepared in example 1, 2# is the modified polyvinyl alcohol prepared in example 2, 3# is the modified polyvinyl alcohol prepared in example 3, and 4# is the modified polyvinyl alcohol prepared in example 4.
Detailed Description
The present invention is described in detail below with reference to specific examples, which are given for the purpose of further illustrating the invention and are not to be construed as limiting the scope of the invention, and the invention may be modified and adapted by those skilled in the art in light of the above disclosure. All the raw materials and reagents of the invention are commercial products.
Preparation of modified polyvinyl alcohol dispersant according to the invention
Example 1
To the polymerization reactor, 100 parts by weight of vinyl acetate, 100 parts by weight of methanol, 3.0 parts by weight of n-valeraldehyde and 0.068 parts by weight of Azobisisobutyronitrile (AIBN) were added. After the replacement with nitrogen, the temperature was raised, and the polymerization was terminated after 5 hours, with timing being started when the reflux was about 60 ℃. Unreacted vinyl acetate was then removed to give a methanol solution of polyvinyl acetate. To the resulting methanol solution of polyvinyl acetate (concentration 32-35%) was added a methanol solution of 8 millimoles of sodium hydroxide per mole of vinyl acetate unit. After hydrolysis was carried out at 40 ℃ for 45 minutes, glacial acetic acid in an amount equivalent to that of sodium hydroxide was added to terminate the reaction, and the reaction mixture was centrifuged to obtain a PVA resin (degree of polymerization of No. 1: 738, degree of alcoholysis: 71.96 mol%). The obtained PVA resin was dried in a vacuum oven at 110 ℃ under a vacuum degree of-0.01 MPa for 2 hours to obtain a pale yellow powder.
Example 2
To the polymerization reactor, 100 parts by weight of vinyl acetate, 80 parts by weight of methanol, 3.5 parts by weight of n-valeraldehyde and 0.06 part by weight of bis (4-tert-butylcyclohexyl) peroxydicarbonate were charged. After the replacement with nitrogen, the temperature was raised, and the polymerization was terminated after 5 hours, with timing being started when the reflux was about 60 ℃. Unreacted vinyl acetate was then removed to give a methanol solution of polyvinyl acetate. To the resulting methanol solution of polyvinyl acetate (concentration 32-35%) was added a methanol solution of 8 millimoles of sodium hydroxide per mole of vinyl acetate unit. After hydrolysis was carried out at 40 ℃ for 45 minutes, glacial acetic acid in an amount equivalent to that of sodium hydroxide was added to terminate the reaction, and the reaction mixture was centrifuged to obtain a PVA resin (degree of polymerization of No. 2: 788, degree of alcoholysis: 72.58 mol%). The obtained PVA resin was dried in a vacuum oven at 110 ℃ under a vacuum degree of-0.01 MPa for 2 hours to obtain a pale yellow powder.
Example 3
To the polymerization reactor, 100 parts by weight of vinyl acetate, 60 parts by weight of methanol, 4.5 parts by weight of n-valeraldehyde and 0.06 part by weight of azobisisoheptonitrile were added. After the replacement with nitrogen, the temperature was raised, and the polymerization was terminated after 5 hours, with timing being started when the reflux was about 60 ℃. Unreacted vinyl acetate was then removed to give a methanol solution of polyvinyl acetate. To the resulting methanol solution of polyvinyl acetate (concentration 32-35%) was added a methanol solution of 8 millimoles of sodium hydroxide per mole of vinyl acetate unit. After hydrolysis was carried out at 40 ℃ for 45 minutes, glacial acetic acid equivalent to sodium hydroxide was added to terminate the reaction to obtain a methanol solution of the PVA resin, and the methanol solution of the PVA resin was uniformly fed by a screw pump into a nitrogen-protected centrifuge to carry out solid-liquid separation to obtain a PVA resin (degree of polymerization: 821 # 3, degree of alcoholysis: 72.31 mol%). The obtained PVA resin was dried in a vacuum oven at 110 ℃ under a vacuum degree of-0.03 MPa for 2 hours to obtain a pale yellow powder.
Example 4
To the polymerization reactor, 100 parts by weight of vinyl acetate, 20 parts by weight of methanol, 6.0 parts by weight of n-valeraldehyde and 0.08 parts by weight of bis (3,5, 5-trimethylhexanoyl) peroxide were added. After the replacement with nitrogen, the temperature was raised, and the polymerization was terminated after 5 hours, with timing being started when the reflux was about 60 ℃. Unreacted vinyl acetate was then removed to give a methanol solution of polyvinyl acetate. To the resulting methanol solution of polyvinyl acetate (concentration 32-35%) was added a methanol solution of 8 millimoles of sodium hydroxide per mole of vinyl acetate unit. After hydrolysis was carried out at 40 ℃ for 45 minutes, glacial acetic acid equivalent to sodium hydroxide was added to terminate the reaction to obtain a methanol solution of the PVA resin, and the methanol solution of the PVA resin was uniformly fed by a screw pump into a centrifuge protected with nitrogen to carry out solid-liquid separation to obtain a PVA resin (degree of polymerization of No. 4: 645, degree of alcoholysis: 73.04 mol%). The obtained PVA resin was dried in a vacuum oven at 110 ℃ under a vacuum degree of-0.01 MPa for 3 hours to obtain a pale yellow powder.
Performance testing
Carrying out alcoholysis degree measurement according to the specification of appendix D in GB/T12010.2-2010; the viscosity was measured using a Brookfield viscometer as specified in appendix E of GB/T12010.2-2010; FTIR measurement is carried out by adopting a VERTEX 70 Fourier transform infrared spectrometer (Bruker, Germany), wherein the measurement range is 7500-370 cm & lt-1 & gt, and the common wave number range is 4000-400 cm & lt-1 & gt; the ultraviolet absorption was measured by using an ultraviolet/visible spectrometer UV-3700 (Shimadzu Japan) at a concentration of 0.1 wt%. The polymerization degree, alcoholysis degree, viscosity and ultraviolet absorption of the modified polyvinyl alcohol prepared in examples 1-4 of the present invention are specifically shown in table 1 below.
TABLE 1 Properties of modified polyvinyl alcohols prepared in examples 1-4
. The modified polyvinyl alcohols prepared in examples 1 to 4 had an absorption at 215nm, as measured by uv absorption, ascribed to the-CO-CH ═ CH-structure in the PVA resin, and uv absorption values of 0.1 to 0.7; the absorption at 280nm is ascribed to-CO- (CH ═ CH) in the PVA resin2-structure, uv absorption value of 0.2-0.7; the absorption at 320nm is ascribed to-CO- (CH ═ CH) in the PVA resin3-structure, uv absorption value of 0.05-0.5. The modified polyvinyl alcohols prepared in examples 1-4 were subjected to infrared spectroscopy, and the results are shown in FIG. 1, it is apparent that 1730-1740cm in FTIR spectrum of the modified polyvinyl alcohol of the present invention-1There is a strong carbonyl absorption peak. The NMR spectra of the modified polyvinyl alcohols prepared in examples 1 to 4 are shown in FIG. 2.
Example 5
To the polymerization reactor, 100 parts by weight of vinyl acetate, 100 parts by weight of methanol, 4.0 parts by weight of valeraldehyde and 0.088 parts by weight of Azobisisobutyronitrile (AIBN) were added. After the replacement with nitrogen, the temperature was raised, and the polymerization was terminated after 4 hours, with a timer started at about 60 ℃ with reflux. Unreacted vinyl acetate was then removed to give a methanol solution of polyvinyl acetate. To the resulting methanol solution of polyvinyl acetate (concentration 10-35%) was added a methanol solution of 10 millimoles of sodium hydroxide per mole of vinyl acetate unit. Hydrolyzing at 40 deg.C for 35 min, adding glacial acetic acid equal to sodium hydroxide to terminate reaction to obtain PVA-methanol mixture, and centrifuging to obtain PVA resin. The obtained PVA resin was dried in a vacuum oven at 110 ℃ under a vacuum degree of-0.01 MPa for 2 hours to obtain a pale yellow powder.
Modified polyvinyl alcohols were prepared by operating examples 6 to 10 according to the parameters of table 2 with reference to the preparation method of example 5 described above, and the performance parameters of the prepared modified polyvinyl alcohols were measured with reference to the performance test methods of examples 1 to 4. The polymerization degree and alcoholysis degree, ultraviolet absorption, viscosity, infrared and other performance parameters of the modified polyvinyl alcohols prepared in examples 5-10 are specifically shown in Table 2 below.
TABLE 2 Properties of modified polyvinyl alcohols prepared in examples 5-10
As shown in Table 2, the modified polyvinyl alcohols prepared in examples 5 to 10 of the present invention had UV absorption values of 0.1 to 0.7 at 215 nm; ultraviolet absorption value at 280nm is 0.2-0.7; the ultraviolet absorption value at 320nm is 0.05-0.5. The modified polyvinyl alcohols prepared in examples 5 to 10 were subjected to infrared spectroscopic measurement at 1730-1740cm-1There is a strong carbonyl absorption peak.
Comparative examples
The polymerization time of examples 1 to 4 was extended from 5 hours to 10 hours to prepare a modified polyvinyl alcohol. As a result, the polymerization degree of the product is slightly improved along with the prolonging of the reaction time, but the branching is serious, so that the short branched chain in the subsequent alcoholysis process is seriously chain-removed, the viscosity of the final product is directly influenced, the ultraviolet absorption is also greatly influenced, the overlong reaction time seriously influences the quality of the invention, and the product meeting the requirement is difficult to prepare.
Example 11
The modified polyvinyl alcohol of the invention was used as a dispersing agent for suspension polymerization of vinyl chloride.
The use of 4 of the modified polyvinyl alcohols prepared in examples 1 to 4 as a primary dispersant in the suspension polymerization of vinyl chloride was examined. The following reports the use of the modified polyvinyl alcohol in vinyl chloride polymerization.
Based on the polymerization process and formula of national standard SG-5 type PVC resin, wherein deionized water: 16.0L, vinyl chloride monomer: 10.0L, 8g of modified polyvinyl alcohol dispersant, 30L of polymerization kettle (West chemical machinery factory), three-legged centrifuge (northeast mechanical factory of Shenyang), 30L/h quantitative pump (general machinery factory of Tianjin), and the variety and dosage of other raw materials and auxiliary agents are unchanged. The modified polyvinyl alcohol dispersants prepared in examples 1 to 4 were used in the same amount for the tests, and the change of the PVC resin index was compared.
The process conditions are as follows:
washing a polymerization kettle, adding quantitative deionized water, starting stirring, adding a dispersing agent, an initiator and other auxiliaries (refer to the polymerization process and formula of national standard SG-5 type PVC resin and 2009 edition polyvinyl chloride process technology, chemical industry publishing Co.), pressing a quantitative vinyl chloride monomer into the kettle cover, cold stirring for 10min, heating to the polymerization reaction temperature for polymerization, adding a terminator after the polymerization reaction is finished, discharging, centrifuging, and sampling for testing.
Test execution criteria:
viscosity number: is carried out according to the GB/T3401-1987 standard; apparent density: performed with reference to GB/T3402 appendix A; plasticizer absorption amount: performed with reference to GB/T3400-1993; screening: reference GB/T2916-1997 standard implementation; the number of "fish eyes": performed with reference to the GB/T4611-1993 standard; whiteness: performed with reference to the GB5761 standard. The data of this SG-5 type PVC resin according to the national standard tests are shown in Table 3.
TABLE 3 SG-5 resin quality
As is clear from Table 3, the resin obtained using the modified polyvinyl alcohol of the present invention as a main dispersant had a viscosity of 107-112ml/g, an apparent density of 0.45 to 0.50g/ml, and an absorption amount of a plasticizer of more than 20%.
TABLE 4 distribution of the PVC resin particles of type SG-5
As shown in Table 4, the resin particles of 45-80 mesh in the PVC resin prepared by using the modified polyvinyl alcohol of the invention as the main dispersant account for 4.5-6.0%, and the resin particles of 100-140 mesh account for 80.0-85.0%. The screening result shows that the numerical particle distribution can meet the requirement and the concentration rate is better.
TABLE 5 rheological Properties of SG-5 type resin
As is clear from Table 5, the processability of the PVC resin obtained by using the modified polyvinyl alcohol of the present invention as a main dispersing agent was up to the standard of the superior products.
The scanning electron micrograph of the SG-5 type resin prepared by using the modified polyvinyl alcohol of example 1 of the invention as a main dispersant is shown in figure 3, and the particle size distribution of the type resin is uniform. From the technical process and the result, the modified polyvinyl alcohol has good foaming inhibition performance when being used as a main dispersing agent for vinyl chloride polymerization, and has good glue retention performance and dispersion performance.
Referring to example 11, based on the polymerization process and formula of national standard SG-5 type PVC resin, the modified polyvinyl alcohol prepared in examples 5-10 of the present invention is used as the main dispersing agent for vinyl chloride suspension polymerization, the prepared resin has viscosity of 107-80 meshes 112ml/g, apparent density of 0.45-0.50g/ml, plasticizer absorption of more than 20%, resin particles of 45-80 meshes account for 5.30%, and resin particles of 100-140 meshes account for 80.65%, and the resin particles are uniformly distributed and have better concentration rate. The technological process and the results show that the modified polyvinyl alcohol of the invention is used as a main dispersant in the suspension polymerization process of vinyl chloride, has good foam inhibition performance, and simultaneously has good glue retention performance and dispersion performance.
Claims (10)
1. The modified polyvinyl alcohol is prepared from raw materials including methanol, vinyl acetate monomer, valeraldehyde and initiator, and is characterized in that: the ultraviolet absorption value of the modified polyvinyl alcohol at 215nm is 0.1-0.7, the ultraviolet absorption value at 280nm is 0.2-0.7, and the ultraviolet absorption value at 320nm is 0.05-0.5.
2. The modified polyvinyl alcohol of claim 1, wherein: 1730-1740cm in FTIR spectrum of the modified polyvinyl alcohol-1There is a strong carbonyl absorption peak.
3. The modified polyvinyl alcohol of claim 1, wherein: the polymerization degree of the modified polyvinyl alcohol is 500-1000, the alcoholysis degree is 65-78%, and the percentage is calculated by mol percent; the viscosity of the modified polyvinyl alcohol 4% aqueous solution is 4.0-8.0 mpa.s.
4. The modified polyvinyl alcohol of claim 1, wherein: the initiator is one or a combination of more of azodiisobutyronitrile, azodiisoheptonitrile, bis (4-tert-butylcyclohexyl) peroxydicarbonate, pivalic acid-tert-amyl peroxypivalate, bis (2-ethylhexyl) peroxydicarbonate, bis (3,5, 5-trimethylhexanoyl) peroxide, dipropyl peroxydicarbonate, potassium persulfate, ammonium persulfate, sodium bisulfite, sodium bicarbonate, tartaric acid or rongalite.
5. The modified polyvinyl alcohol of any one of claims 1 to 4, wherein: 20-100 parts of methanol, 100 parts of Vinyl Acetate (VAC), 2.5-7.5 parts of valeraldehyde and 0.015-0.175 part of initiator.
6. The modified polyvinyl alcohol as claimed in any one of claims 1 to 5, comprising the steps of polymerization, hydrolysis, solid-liquid separation and drying, wherein: the polymerization step is to add methanol, vinyl acetate monomer, valeraldehyde and initiator into a reaction kettle and carry out polymerization reaction for 3-5 hours at the temperature of 60-65 ℃.
7. The modified polyvinyl alcohol of claim 6, wherein: the drying is to dry the separated solid part in a vacuum drier, the drying temperature is 70-150 ℃, the vacuum degree is-0.03 to-0.01 MPa, and the drying time is 2-4 hours.
8. A method for preparing the modified polyvinyl alcohol dispersant as claimed in claim 1, comprising the steps of polymerization, hydrolysis, solid-liquid separation and drying, characterized in that: the polymerization is to add methanol, vinyl acetate monomer, valeraldehyde and initiator into a polymerization kettle with stirring at normal pressure; after the addition is finished, reacting for 3-5 hours at 60-65 ℃; after the reaction is finished, heating up to evaporate and recovering the residual monomer to obtain a concentrated polyvinyl acetate methanol solution; the hydrolysis is to adjust the concentration of polyvinyl acetate methanol solution to 10-30% by using methanol, keep the temperature at 35-50 ℃ for 1-2 hours, then add sodium hydroxide methanol solution to carry out hydrolysis reaction for 5-120 minutes, and add glacial acetic acid to stop the reaction after the reaction is finished, so as to obtain pure white polyvinyl alcohol methanol solid-liquid mixture; the solid-liquid separation is to uniformly send the hydrolyzed polyvinyl alcohol methanol solid-liquid mixture into a centrifuge protected by nitrogen for solid-liquid separation; the drying is to dry the separated solid part in a vacuum drier, the drying temperature is 70-150 ℃, the vacuum degree is-0.03 to-0.01 MPa, and the drying time is 2-4 hours.
9. Use of the modified polyvinyl alcohol according to any one of claims 1 to 5 as dispersing agent for suspension polymerization of vinyl chloride.
10. Use of the modified polyvinyl alcohol of any one of claims 1 to 5 as a primary dispersing agent for suspension polymerization of vinyl chloride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710941586.5A CN109651542B (en) | 2017-10-11 | 2017-10-11 | Modified polyvinyl alcohol dispersant, preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710941586.5A CN109651542B (en) | 2017-10-11 | 2017-10-11 | Modified polyvinyl alcohol dispersant, preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109651542A CN109651542A (en) | 2019-04-19 |
| CN109651542B true CN109651542B (en) | 2021-05-07 |
Family
ID=66109013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710941586.5A Active CN109651542B (en) | 2017-10-11 | 2017-10-11 | Modified polyvinyl alcohol dispersant, preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109651542B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103788234A (en) * | 2012-10-26 | 2014-05-14 | 中国石油化工集团公司 | Auxiliary dispersant and preparation method |
| CN105153335A (en) * | 2014-05-27 | 2015-12-16 | 中国石油化工集团公司 | Polyvinyl alcohol, and preparation method and application thereof |
| 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 |
| CN107189002A (en) * | 2017-06-13 | 2017-09-22 | 天津辛德玛悬浮剂有限公司 | Chemical modification prepares itself tool defoaming function polyvinyl alcohol and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB568914A (en) * | 1942-02-11 | 1945-04-26 | Du Pont | Manufacture of polyvinyl acetal resins |
-
2017
- 2017-10-11 CN CN201710941586.5A patent/CN109651542B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103788234A (en) * | 2012-10-26 | 2014-05-14 | 中国石油化工集团公司 | Auxiliary dispersant and preparation method |
| CN105153335A (en) * | 2014-05-27 | 2015-12-16 | 中国石油化工集团公司 | Polyvinyl alcohol, and preparation method and application thereof |
| 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 |
| CN107189002A (en) * | 2017-06-13 | 2017-09-22 | 天津辛德玛悬浮剂有限公司 | Chemical modification prepares itself tool defoaming function polyvinyl alcohol and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109651542A (en) | 2019-04-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110790854B (en) | Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and preparation method thereof | |
| EP3265505B1 (en) | Pvoh dispersant for vcm polymerization | |
| KR101168400B1 (en) | Suspension polymerization method for polyvinylchloride and polyvinylchloride produced thereby | |
| US10647791B2 (en) | Polyvinyl alcohol used as dispersing agents for polyvinyl chloride suspension polymerization, dispersing agents comprising the polyvinyl alcohol, and method for producing polyvinyl chloride using the polyvinyl alcohol | |
| EP3284761A1 (en) | Vinyl chloride-based polymer, preparation method therefor, and thermoplastic resin composition containing same | |
| CN109651541B (en) | Linear chain dialdehyde modified polyvinyl alcohol and preparation method and application thereof | |
| CN109651542B (en) | Modified polyvinyl alcohol dispersant, preparation method and application thereof | |
| CN109234046B (en) | Nonionic polymer surfactant and synthesis method thereof | |
| CN106854256B (en) | Melt-processable modified polyvinyl alcohol and preparation method thereof | |
| CN110028602B (en) | Method for reducing impurity content in industrial polyvinyl alcohol | |
| KR101382897B1 (en) | A method for preparing vinyl chlorides resin having improved workability | |
| US2705226A (en) | Production of vinyl chloride polymers | |
| KR101683333B1 (en) | Method for preparing vinyl chloride based resin | |
| KR101411098B1 (en) | Method of preparing polyvinyl chloride comprising butyl acrylate | |
| KR101553099B1 (en) | Method of preparing vinyl chloride resin having excellent processibility and productivity | |
| CN105273111A (en) | Method for reducing fouling of steam stripping apparatus during polyvinyl chloride production | |
| KR101253912B1 (en) | A method for preparing vinyl chlorides resin having good polymerization productivity | |
| CN109651540A (en) | A kind of modified polyvinylalcohol and its preparation method and application | |
| KR20210034418A (en) | preparation method of vinyl chloride-based polymer | |
| EP0450317B1 (en) | Vinyl acetate/vinyl alcohol copolymer, production process and use thereof | |
| CN115991841B (en) | EVOH resin composition with excellent thermal stability and preparation method thereof | |
| TWI812760B (en) | Polyvinyl alcohol-based polymers, and molded articles using polyvinyl alcohol-based polymers | |
| US11787887B2 (en) | Method of producing vinyl chloride-based polymer | |
| KR101623623B1 (en) | Method of preparing vinyl chloride resin having excellent processibility and productivity | |
| JPH0246604B2 (en) |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |