CN104530277A - Polyvinyl alcohol and preparation method thereof - Google Patents
Polyvinyl alcohol and preparation method thereof Download PDFInfo
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- CN104530277A CN104530277A CN201410684104.9A CN201410684104A CN104530277A CN 104530277 A CN104530277 A CN 104530277A CN 201410684104 A CN201410684104 A CN 201410684104A CN 104530277 A CN104530277 A CN 104530277A
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- polyvinyl alcohol
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Abstract
The invention discloses polyvinyl alcohol and a preparation method thereof, the polyvinyl alcohol is a liquid, the alcoholysis degree is below 50%, and the degree of polymerization is 100-350. The preparation method is as follows: A) manufacturing low polymerization degree polyvinyl acetate by solution polymerization method; and B) manufacturing the liquid polyvinyl alcohol by low alcoholysis degree polyvinyl alcohol process by a kneading machine alcoholysis method. The product does not need to be dry, the process is simple, monomer conversion rate is high, energy consumption is low, the prepared liquid polyvinyl alcohol is insoluble in water, and the polyvinyl alcohol can be specifically used as a special adhesive.
Description
Technical field
The invention belongs to polyvinyl alcohol technical field, be specifically related to aqueous polyvinyl alcohol of low polymerization degree low alcoholysis level and preparation method thereof.
Background technology
Polyvinyl alcohol (PVA) is a kind of important water-soluble high-molecular compound grown up at the beginning of the 5O age in 20th century.Application is very extensive, can be used to producd fibers, also can be used as chemical & blended fabric slurry, coating, tackiness agent, emulsifying agent, papermaking processing aid etc.Along with the development of science and technology, day by day urgent to the demand of different viscosity, different alcoholysis degree polyvinyl alcohol (PVA).Find out from a lot of research both domestic and external, polyvinyl alcohol (PVA) product is to height two poles development, and namely viscosity and alcoholysis degree develop to higher and lower both direction.Polyvinyl alcohol (PVA) product of these different viscositys and alcoholysis degree has property, high added value and feature in short supply, and (PVA) of low-viscosity and low alcoholysis level is except the general characteristic (as solvability under water absorbability, ventilation property, nontoxicity, high temperature is stablized) with conventional polyvinyl alcohol (PVA), also there is the advantages such as solvability in cold water is good, biodegradable, therefore, purposes is widely had, as industries such as paper conversion, tamanori, coating, film, medicine, makeup in non-fiber.
Because polyvinyl alcohol can not with unbound state stable existence, polyvinyl alcohol (PVA) can not directly obtain from vinyl alcohol polymerization, the polyvinyl acetate that adopts carries out alcoholysis to prepare more under base catalysis at present, namely for preparing the polyvinyl alcohol (PVA) of low polymerization degree, the polyvinyl acetate of low polymerization degree must first be prepared.
In order to improve the use properties of polyvinyl alcohol product in prior art, in solution polymerization, adding the second polymerization single polymerization monomer carry out graft copolymerization, make polyvinyl acetate molecular chain introduce second comonomer.Carry out the polyvinyl alcohol that modification is prepared in alcoholysis again.
Patent 200810153707 discloses a kind of preparation method of polyvinyl alcohol with low degree of polymerization, acetaldehyde is adopted to manufacture polyvinyl alcohol with low degree of polymerization as molecular weight regulator, adopt alkane to carry out Suspension alcoholysis as suspension agent, make powder shaped polyethylene alcohol, alcoholysis degree scope 72.4-77.9%.The method suspension agent reclaims difficulty.
Patent CN01115186.2 discloses a kind of preparation method of polyvinyl alcohol with low alcoholysis level, ester class, ethers, ketone, hydro carbons etc. are added to as solvent with methyl alcohol be solvent polyvinyl acetate alcoholysis reaction system in, add condensation agent after completion of the reaction again and polyvinyl alcohol with low alcoholysis level separated out.The alcoholysis degree of product is 50 ~ 90%.
Be equivalent to above-mentioned two methods and all with the addition of the third material (even the 4th kind) in polymerization and alcoholysis process, method technique of the present invention is simple, and quality product is convenient to control, and solvent is easy to reclaim, low cost and other advantages.
The prior art also high-alkali alcoholysis method of useful twin screw alcoholysis machine can produce cotton-shaped polyvinyl alcohol, has carried out mechanical disintegration in production process.
The feature of high-alkali alcoholysis method is alcoholysis catalysts sodium hydroxide water dissolution (concentration is 300-350 grams per liter), the usage quantity of catalyzer is higher (mol ratio about 0.12%), alcoholysis speed fast (20-60 second), produces the polyvinyl alcohol of high alcoholysis degree (more than 99.8%).
Specific practice is: the methanol solution (concentration about 25%) of polyvinyl acetate and catalyzer (aqueous sodium hydroxide solution of 300-350 grams per liter) are uniformly mixed, alcoholysis reaction (residence time of reactant in alcoholysis machine is very short) is there is in screw rod alcoholysis machine, then by product through three times pulverize after, squeezing enter drying machine drying after obtain polyvinyl alcohol.
Shortcoming: alcoholysis degree is uncontrollable, can only the polyvinyl alcohol of production complete alcoholysis type (more than 99.8%).
Prior art also useful belt alcoholysis machine low alkalinity alcoholysis can production sheet polyvinyl alcohol, has carried out mechanical disintegration in production process.
The feature of belt alcoholysis machine low alkalinity alcoholysis is alcoholysis catalysts sodium hydroxide dissolve with methanol (concentration is 30-80 grams per liter), the usage quantity of catalyzer is lower (about mol ratio 0.010-0.016%), alcoholysis speed slow (20-40 minute), can produce the polyvinyl alcohol of alcoholysis degree 80-99.99%.
Belt alcoholysis machine be a long 20-40 rice can the belt (1.0--1.5 rice is wide) of cycle rotation.Reactant stops about 30 minutes on belt.Reactant is from the good solution shape of mobility progressively gel and solidifying.
Specific practice is: the methanol solution (about concentration 25-30%) of polyvinyl acetate (PVA) and catalyzer (sodium hydrate methanol solution of 30-80 grams per liter) are uniformly mixed, belt occurs alcoholysis reaction (residence time of reactant on belt has about 30 minutes), then by product through pulverizing after, squeezing enter drying machine drying after obtain polyvinyl alcohol.
When shortcoming is the polyvinyl alcohol when production less than 75%, reactant is bonded on belt because viscosity is too large, substantially can not produce.
Prior art does not also have the polyvinyl alcohol product of low alcoholysis level (less than 50%) simultaneously low polymerization degree liquid state.
Summary of the invention
The object of the invention is to overcome deficiency of the prior art, and provide the aqueous polyvinyl alcohol of a kind of low polymerization degree low alcoholysis level and preparation method thereof, this product can use as special adhesive.The preparation method of the aqueous polyvinyl alcohol of low polymerization degree low alcoholysis level that the present invention relates to, technique is simple, and monomer conversion is high, does not need drying.
For achieving the above object, the technical solution used in the present invention is:
A kind of polyvinyl alcohol, this polyvinyl alcohol is liquid, and alcoholysis degree is below 50 % by mole, and the polymerization degree is 100-350.
Described alcoholysis degree is preferably between 40 % by mole-50 % by mole.
The preparation method of described polyvinyl alcohol, is specially:
A) solution polymerization process manufactures the polyvinyl acetate (PVA) of the polymerization degree between 100-350;
B) described polyvinyl acetate (PVA) and methyl alcohol are formulated as the polyvinyl acetate (PVA) methanol solution that mass concentration is 30%--60%, 1000 parts of polyvinyl acetate (PVA) methanol solutions are added in kneader, total amount is no more than 80% of kneader volume, controlling temperature of reaction is 25 DEG C-50 DEG C, stirring velocity 5-50 revs/min, add sodium hydrate methanol solution 1--10 part that mass concentration is 5%-8% again, continue stirring reaction 30--300 minute, obtain liquid pva.
It is preferred that solution polymerization process manufactures low polymerization degree polyvinyl acetate (PVA): use ethanol is solvent, and sulphur fork pentanoic is stopper, Vinyl Acetate Monomer 1000 parts (in mass), ethanol 1000--1500 part, Diisopropyl azodicarboxylate 1--5 part, polymerization time 3-10 hours, polymerization temperature 60 DEG C-65 DEG C.
Compared with prior art, advantage of the present invention is:
1, prior art does not also have the polyvinyl alcohol product of low alcoholysis level (less than 50%) simultaneously low polymerization degree liquid state, and the present invention obtains alcoholysis degree below 50 % by mole, and the polymerization degree is the liquid pva of 100-350, can use as special adhesive.
2, the product that the method is prepared does not need drying, and technique is simple, and monomer conversion is high, and energy consumption is low, and obtained aqueous polyvinyl alcohol is water insoluble.
Embodiment
Below by embodiment, the present invention is specifically described; what be necessary to herein means out is that following examples are only used to further illustrate the present invention; can not be interpreted as limiting the scope of the invention, the person skilled in the art in this field can make some nonessential changes according to foregoing invention content to the present invention.
Alcoholysis degree is according to GB/T 12010.The method that 2-2010 Appendix D specifies measures.Percentage composition not specified in embodiment is mass percentage.
embodiment 1
In 5 liters of double-layer glass reaction kettles with distillation and reflux, add ethanol 1200 grams, vinyl acetate resin 1000 grams, is warming up to 65 DEG C in still after nitrogen replacement, then adds Diisopropyl azodicarboxylate 2 grams, opens and stirs, react 6 hours.Add 0.1g stopper termination reaction, be warming up to 80 DEG C and allow still internal solvent volatilize, methyl alcohol is added in midway makes for 3-5 time unreacted vinyl acetate resin in still evaporate completely.Then be cooled to 40 DEG C, then add methyl alcohol about 1500 grams product is dissolved, and concentration is adjusted to 40%.After testing: monomer conversion is 91.2%, the polymerization degree 210.
The methanol solution 1000 parts of the polyvinyl acetate (PVA) of 40% is added (total amount is no more than 80% of volume) in kneader, and temperature of reaction is 45 DEG C, stirring velocity 10 revs/min, adds the sodium hydrate methanol solution 4 parts of 5%, continues stirring reaction 150 minutes.The liquiform product obtained.After testing: alcoholysis degree 10.4 % by mole,
embodiment 2
In 5 liters of double-layer glass reaction kettles with distillation and reflux, add ethanol 1000 grams, vinyl acetate resin 1000 grams, is warming up to 65 DEG C in still after nitrogen replacement, then adds Diisopropyl azodicarboxylate 1.8 grams, opens and stirs, react 7 hours.Add 0.1g stopper termination reaction, be warming up to 80 DEG C and allow still internal solvent volatilize, methyl alcohol is added in midway makes for 3-5 time unreacted vinyl acetate resin in still evaporate completely.Then be cooled to 40 DEG C, then add methyl alcohol about 1500 grams product is dissolved, and concentration is adjusted to 40%.After testing: monomer conversion is 88.6%, the polymerization degree 350.
The methanol solution 1000 parts of the polyvinyl acetate (PVA) of 40% is added (total amount is no more than 80% of volume) in kneader, and temperature of reaction is 40 DEG C, stirring velocity 20/ minute, adds the sodium hydrate methanol solution 10 parts of 5%, continues stirring reaction 180 minutes.The liquiform product obtained.After testing: alcoholysis degree 40.8 % by mole,
embodiment 3
In 5 liters of double-layer glass reaction kettles with distillation and reflux, add ethanol 1100 grams, vinyl acetate resin 1000 grams, is warming up to 65 DEG C in still after nitrogen replacement, then adds Diisopropyl azodicarboxylate 1.6 grams, opens and stirs, react 8 hours.Add 0.1g stopper termination reaction, be warming up to 80 DEG C and allow still internal solvent volatilize, methyl alcohol is added in midway makes for 3-5 time unreacted vinyl acetate resin in still evaporate completely.Then be cooled to 40 DEG C, then add methyl alcohol about 1500 grams product is dissolved, and concentration is adjusted to 40%.After testing: monomer conversion is 85.6%, the polymerization degree 260.
The methanol solution 1000 parts of the polyvinyl acetate (PVA) of 40% is added (total amount is no more than 80% of volume) in kneader, temperature of reaction is 35 DEG C, stirring velocity 30/ minute, adds the sodium hydrate methanol solution 8 parts of 5%, continue stirring reaction 200 minutes, the liquiform product obtained.After testing: alcoholysis degree 45.2 % by mole.
Claims (4)
1. a polyvinyl alcohol, is characterized in that, this polyvinyl alcohol is liquid, and alcoholysis degree is below 50 % by mole, and the polymerization degree is 100-350.
2. polyvinyl alcohol according to claim 1, it is characterized in that, described alcoholysis degree is between 40 % by mole-50 % by mole.
3. the preparation method of polyvinyl alcohol described in claim 1 or 2, is characterized in that,
A) solution polymerization process manufactures the polyvinyl acetate (PVA) of the polymerization degree between 100-350;
B) described polyvinyl acetate (PVA) and methyl alcohol are formulated as the polyvinyl acetate (PVA) methanol solution that mass concentration is 30%--60%, 1000 parts of polyvinyl acetate (PVA) methanol solutions are added in kneader, total amount is no more than 80% of kneader volume, controlling temperature of reaction is 25 DEG C-50 DEG C, stirring velocity 5-50 revs/min, add sodium hydrate methanol solution 1--10 part that mass concentration is 5%-8% again, continue stirring reaction 30--300 minute, obtain liquid pva.
4. the preparation method of polyvinyl alcohol according to claim 3, it is characterized in that, steps A) described solution polymerization process manufactures low polymerization degree polyvinyl acetate (PVA) and uses ethanol to be solvent, sulphur fork pentanoic is stopper, Vinyl Acetate Monomer 1000 parts (in mass), ethanol 1000--1500 part, Diisopropyl azodicarboxylate 1--5 part, polymerization time 3-10 hours, polymerization temperature 60 DEG C-65 DEG C.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111720102A (en) * | 2020-06-05 | 2020-09-29 | 青岛鑫源晟石油科技有限公司 | Fine temporary plugging volume fracturing process technology replacing mechanical packing |
| CN112574342A (en) * | 2020-12-16 | 2021-03-30 | 湖北魔洗高新材料制品有限公司 | Preparation method of polyvinyl alcohol raw material for PVA collodion cotton head production |
| CN114426686A (en) * | 2020-10-15 | 2022-05-03 | 中国石油化工股份有限公司 | Method for forming ultra-low viscosity polyvinyl alcohol solid |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103626903A (en) * | 2013-12-10 | 2014-03-12 | 济南开发区星火科学技术研究院 | Production method of polyvinyl alcohol with low polymerization degree and low alcoholysis degree |
| CN103897089A (en) * | 2014-04-01 | 2014-07-02 | 湖南省湘维有限公司 | Crystalloid modified polyvinyl alcohol with low viscosity and preparation method thereof |
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- 2014-11-25 CN CN201410684104.9A patent/CN104530277A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103626903A (en) * | 2013-12-10 | 2014-03-12 | 济南开发区星火科学技术研究院 | Production method of polyvinyl alcohol with low polymerization degree and low alcoholysis degree |
| CN103897089A (en) * | 2014-04-01 | 2014-07-02 | 湖南省湘维有限公司 | Crystalloid modified polyvinyl alcohol with low viscosity and preparation method thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111720102A (en) * | 2020-06-05 | 2020-09-29 | 青岛鑫源晟石油科技有限公司 | Fine temporary plugging volume fracturing process technology replacing mechanical packing |
| CN114426686A (en) * | 2020-10-15 | 2022-05-03 | 中国石油化工股份有限公司 | Method for forming ultra-low viscosity polyvinyl alcohol solid |
| CN114426686B (en) * | 2020-10-15 | 2024-02-09 | 中国石油化工股份有限公司 | Forming method of ultra-low viscosity polyvinyl alcohol solid |
| CN112574342A (en) * | 2020-12-16 | 2021-03-30 | 湖北魔洗高新材料制品有限公司 | Preparation method of polyvinyl alcohol raw material for PVA collodion cotton head production |
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Application publication date: 20150422 |