CN1566165A - Polyvinyl alcohol with high degree of polymerization and its preparing process - Google Patents
Polyvinyl alcohol with high degree of polymerization and its preparing process Download PDFInfo
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- CN1566165A CN1566165A CN 03135392 CN03135392A CN1566165A CN 1566165 A CN1566165 A CN 1566165A CN 03135392 CN03135392 CN 03135392 CN 03135392 A CN03135392 A CN 03135392A CN 1566165 A CN1566165 A CN 1566165A
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Abstract
The invention discloses a polyvinyl alcohol with high degree of polymerization and its preparing process, wherein a suspension polymerization mode and free radical low-temperature triggering system are employed for 2-10 hours of polymerization at 10-60 deg. C, thus obtaining polyvinyl alcohol with high degree of polymerization, alcoholysis reaction is performed to the polyvinyl acetate bo obtain the polyvinyl alcohol with high degree of polymerization.
Description
Technical field
The present invention is the polyvinyl alcohol that obtains a kind of high-polymerization degree with suspension polymerization.
Technical background
Polyvinyl alcohol (PVA) is a kind of excellent property, broad-spectrum polymkeric substance.Its main preparation methods has solution polymerization, mass polymerization, letex polymerization and suspension polymerization.And adopt polyvinyl alcohol of high degree of polymerization to prepare high-strength high-modulus fibre, and can reduce the molecule chain end defective, improve draw ratio, shorten the technological process of production, reduce production costs, the PVA fibre strength of acquisition can reach 20g/d, excellent property.In addition, polyvinyl alcohol of high degree of polymerization can also be used to produce multiple products such as PVA film, PVA sheet material, molding part (as shower nozzle and rotatable parts) and tire core.
The polymerization process of present industrial polyvinyl alcohol is to adopt solution polymerization, the polyvinyl alcohol of acquisition, and the polymerization degree is the highest to be no more than 3000.High-strength high-modulus fibre intensity prepared therefrom is no more than 13g/d.
Mass polymerization is difficult to realize industrialization because polymeric reaction condition is wayward, though the product polymerization degree that obtains is very high, because its degree of branching is also very high, application is restricted.
What the synthetic-highly polymerized degree polyvinyl alcohol of a large amount of patents reports adopted is that method of emulsion polymerization is carried out, as: 1. EP255137,3/1988; 2. the spy opens clear 63,37106/1988; 3. US4818787/1986; 4. US4818788/1987; 5. JP05117307 A2/1993; 6. EP460502 A2/1991.
In the above-mentioned document, EP255137,3/1988 is disclosed in the emulsion that contains nonionic, anionic emulsifier, superoxide, polyvalent metal ion, selective reduction agent vinyl acetate is carried out polymerization, and after saponification can obtain polyvinyl alcohol of high degree of polymerization.But problems such as this method exists, and operation easier is big, polymerization stability is poor, aftertreatment complexity, wastewater treatment capacity are big, remaining emulsifying agent causes the product poor electrical performance in the polyvinyl alcohol of acquisition, and application is restricted.
The spy opens clear 63,37106/1988 report adopts the method for low temperature emulsion polymerization prepared high-polymerization degree polyvinyl ester, make initiator with redox systems such as ferrous sulfate-rongalite, this method polymerization temperature low (at-60～-15 ℃), wayward, washing difficulty, the polyvinyl alcohol viscosity of acquisition be more than 10000, even be higher than 30000.Metal ion such as iron content, sodium in the product, purity difference, application is restricted.US4818787/1986 and US4818788/1987 report is with the method for emulsion polymerization prepared high-polymerization degree, and the polyvinyl alcohol limiting viscosity of acquisition even is higher than 3.2dl/g more than 1.5dl/g.Its polymerization degree is about more than 10000, even surpasses 20000.Because the product polymerization degree is too high, the dissolving difficulty, the solution spinning property is poor, is not suitable for fiber sprinning and uses.
Up to now, adopt suspension polymerization synthesizing polyethylene alcohol, some researchs and patent report arranged:
The spy opens clear 61-148209/1986 and has disclosed a kind of method with the suspension polymerization polyvinyl alcohol of high degree of polymerization, and this method polymerization temperature is below 20 ℃, and polymerization velocity is slow, and polymerization time long (above 48 hours) is difficult to realize industrialization.The polyvinyl alcohol limiting viscosity that obtains is more than the 1.5dl/g, and the polymerization degree is more than 10000, and not mentioned product performance and purposes.
EP250607,7/1988 has disclosed a kind of method with the suspension polymerization polyvinyl alcohol of high degree of polymerization, but the polymerization degree of the polyvinyl alcohol of this method preparation only is 1700, this method does not have industrialized value.
" Process Technology of Polymer " (day), 44 (9) P409-413,1995; Pollimo (" polymkeric substance "), 20 (6), 1004-1013 (Korea Spro) 1996; Colloid Polym.Sci., (" colloidal state polymer science ") 276 (11), 951-959,1998; J.KoreaFiber Soc., (" Korea S fiber association magazine ") 36 (5), 354-360,1999 reports adopt suspension polymerizations to prepare polyvinyl alcohol or polymerization time is oversize, rate of polymerization too slow (polymerization time more than 47 hours, even want more than 100 hour); Or the polymerization degree is low, and transformation efficiency is not high, all is difficult to realize industrialization.The polymerization degree of the polyvinyl alcohol that obtains is no more than 6000, if be used to produce high-strength high-modulus fibre, the PVA fiber of acquisition is no more than 13g/d by force.
Summary of the invention
The purpose of this invention is to provide a kind of method that adopts suspension polymerization, be suitable for the polyvinyl alcohol and the synthesis technique thereof of suitability for industrialized production high-polymerization degree.
The polyvinyl alcohol polymerization degree that this synthesis technique obtains is more than 5000, the best is 6000～8000, dispersity is at 1.5-2.8, the best is 1.8-2.5, is suitable for products such as production high strength high modulus PVA fiber (intensity is greater than 20g/d), PVA film, PVA sheet material, molding part (as shower nozzle and rotatable parts) and tire core.
Its main processes can be expressed as follows:
Monomer preparation → suspension polymerization → separation → alcoholysis → product
The polymerization temperature of suspension polymerization of the present invention is 10～60 ℃, and the best is 20～50 ℃, polymerization time 2～10 hours, and the best is 4～8 hours.
Suspension polymerization system of the present invention is made up of dispersion medium, monomer, dispersion agent, initiator, and its weight percentage is as follows respectively: dispersion medium 40～80%, the best are 50～70%; Monomer 20～60%, the best are 30～50%; Dispersion medium/monomeric mass ratio is between 2: 1～1: 1; Dispersion agent 0～5%, the best are 0.02～2%, initiator 0～4%, and the best is 0.02～2%.
Dispersion medium of the present invention is a soft water; Monomer is a vinyl-acetic ester; Dispersion agent is that the vinyl-acetic ester molar content is 0～40% vinyl alcohol-vinyl acetate copolymer, polyacrylic acid an alkali metal salt, acrylic or methacrylic acid or toxilic acid and multipolymer, gelatin, carboxymethyl cellulose, Natvosol and the composition thereof of vinylbenzene or acrylate or methacrylic ester; Initiator is benzoyl peroxide, dilauroyl peroxide, peroxidation trimethylacetic acid tertiary butyl, di-isopropyl peroxydicarbonate, di-cyclohexylperoxy dicarbonate, acetyl peroxide hexanaphthene sulphonyl, Diisopropyl azodicarboxylate, 2,2'-Azobis(2,4-dimethylvaleronitrile) or azo two different pelargonitrile and combinations thereof.
0～60 ℃ of the temperature of reaction of alcoholysis reaction of the present invention, the best are 20～40 ℃, and in 0.1～2 hour reaction times, the best is 0.4～1.5 hour.
Alcoholysis liquid of the present invention is made up of the polyvinyl acetate of methyl alcohol, sodium hydroxide, soft water and above-mentioned polymerization gained.The weight percentage of alcoholysis liquid is as follows respectively: polyvinyl acetate 2～30%, the best are 4～25%; Methyl alcohol 65～97%, the best are 60～95%; Sodium hydroxide 1～7%, the best are 1.5～6%; Soft water 0～15%, the best are 0.2～10%.
The present invention has following advantage:
1, the polyvinyl alcohol polymerization degree of the present invention's acquisition is more than 5000, and the best is 6000-8000, and dispersity is low, and the linear lag is good.
2, polymerization time of the present invention is short, speed is fast, only is 2～10 hours, and the transformation efficiency height can reach 50%, and synthesis technique is simple, easy to operate, is suitable for industrialization.
3, the polyvinyl alcohol of high degree of polymerization of the present invention's acquisition also can be used for the production of PVA film, PVA sheet material, molding part such as shower nozzle and rotatable parts and ratch tire core etc., broad market prospect except that being particularly suitable for spinning the high strength high modulus PVA fiber.
Embodiment
Below by embodiment the present invention is carried out concrete description; be necessary to be pointed out that at this following examples only are used for the present invention is further detailed; can not be interpreted as limiting the scope of the invention, the person skilled in the art in this field can make some nonessential improvement and adjustment to the present invention according to the invention described above content.
Embodiment 1:
In reactor, feed nitrogen, add 56.1 parts of soft water, and with 42.5 parts of vinyl-acetic esters, 1 part of gelatin, 0.2 part of Diisopropyl azodicarboxylate and 0.2 part of azo two different pelargonitriles adding reactor, temperature is controlled at 38 ℃, polyreaction 4 hours, the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 79.5 parts of methyl alcohol, 0.5 part of soft water again, be made into 20% solution, under 30 ℃ of temperature, the sodium hydroxide alcoholysis of adding 1.5% 30 minutes gets white polyethylene powder alcohol product, and its polymerization degree is 6200, alcoholysis degree 99.8%, dispersity 2.41.
Comparative Examples 1: press operation and the condition of embodiment 1, temperature becomes 65 ℃ when being polymerization, and the polymerization degree of the PVA that obtains is 4800, and dispersity is 5.10.
Embodiment 2:
In reactor, feed nitrogen, add 58.6 parts of soft water, and 40 parts of vinyl-acetic esters, 0.4 part of Diisopropyl azodicarboxylate and 1 part of Natvosol are added reactor.Temperature is controlled at 40 ℃, polyreaction 3 hours, the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 78.5 parts of methyl alcohol, 3.5 parts of soft water again, be made into 18% solution, under 30 ℃ of temperature, add 2.5% sodium hydroxide alcoholysis 35 minutes, get white polyethylene powder alcohol product, its polymerization degree is 7000, alcoholysis degree 99.9%, dispersity 2.30.
Comparative Examples 2: press operation and the condition of embodiment 2, only the consumption with the initiator Diisopropyl azodicarboxylate becomes 4.1%, and then reaction is violent during polymerization, and wayward, the PVA polymerization degree that obtains is 4200, and dispersity is 4.50.
Embodiment 3:
In reactor, feed nitrogen; add 61 parts of soft water; 38 parts of vinyl-acetic esters, 0.2 part Diisopropyl azodicarboxylate, 0.3 part of acetyl peroxide hexanaphthene sulphonyl and 0.5 part of vinyl alcohol-vinyl acetate copolymer are added reactor; temperature is controlled at 30 ℃; polyreaction 3 hours; the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 80 parts of methyl alcohol, 5 parts of soft water again; be made into 15% solution; under 20 ℃ of temperature; add 3% sodium hydroxide alcoholysis 80 minutes, get white polyethylene powder alcohol product, its polymerization degree is 6000; alcoholysis degree 99.8%, dispersity 1.80.
Comparative Examples 3: press operation and the condition of embodiment 3, only polymerization time is extended to 11 hours, though the polymerization yield increases, the PVA polymerization degree that obtains is 4200, dispersity 3.83.
Embodiment 4:
In reactor, feed nitrogen, add 42.1 parts of soft water, and with 52.7 parts of vinyl-acetic esters, 2.5 part vinyl alcohol-vinyl acetate copolymer, 1 part of acrylic acid and acrylic ester copolymers, 0.5 part polyacrylic acid an alkali metal salt, 0.6 part Diisopropyl azodicarboxylate, 0.3 part azo two different pelargonitriles and 0.3 part of benzoyl peroxide add reactor, temperature is controlled at 15 ℃, polyreaction 10 hours, the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 88 parts of methyl alcohol again, 6.0 in part soft water, be made into 6% solution, under 55 ℃ of temperature, the sodium hydroxide alcoholysis of adding 3.8% 25 minutes, get white polyethylene powder alcohol product, its polymerization degree is 8000, alcoholysis degree 99.7%, dispersity 1.50.
Embodiment 5:
In reactor, feed nitrogen, add 55 parts of soft water, and with 43.6 parts of vinyl-acetic esters, 1.0 parts of vinylformic acid-Sipacril 2739OFs, 0.2 part of di-cyclohexylperoxy dicarbonate and 0.2 part of benzoyl peroxide adding reactor, temperature is controlled at 25 ℃, reacted 5 hours, the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 85 parts of methyl alcohol, 3 parts of soft water again, be made into 12% solution, under 40 ℃ of temperature, add 5% sodium hydroxide alkali alcoholysis 30 minutes, get white polyethylene powder alcohol product, its polymerization degree is 7500, alcoholysis degree 99.8%, dispersity 1.80.
Comparative Examples 4: operation and condition by example 4, the alcoholysis time is shortened to 5 minutes, then the alcoholysis degree of gained PVA only is 80%.
Embodiment 6:
In reactor, feed nitrogen, add 64.4 parts of soft water, and with 35 parts of vinyl-acetic esters, 0.1 part of Natvosol, 0.3 part of 2,2'-Azobis(2,4-dimethylvaleronitrile) and 0.2 part of dilauroyl peroxide adding reactor, temperature is controlled at 20 ℃, polyreaction 6.5 hours, the polyvinyl acetate that above-mentioned reaction is obtained is dissolved in 65 parts of methyl alcohol, 1 part of soft water again, be made into 35% solution, add 2.0% sodium hydroxide alcoholysis 60 minutes at 25 ℃, get white polyethylene powder alcohol product, its polymerization degree is 6500, alcoholysis degree 99.9%, dispersity 2.25.
Embodiment 7:
In reactor, feed nitrogen, add 72.5 parts of soft water, and with 26.8 parts of vinyl-acetic esters, 0.04 part of vinyl alcohol-vinyl acetate copolymer, 0.01 part of azo two different pelargonitrile and 0.02 part of benzoyl peroxide adding reactor, temperature is controlled at 55 ℃, polyreaction 2.5 hours, again the polyvinyl acetate that above-mentioned reaction is obtained be dissolved in 89 parts of methyl alcohol, 7 parts of soft water, be made into 4% solution, add 6.8% sodium hydroxide alcoholysis 100 minutes at 15 ℃, get white polyethylene powder alcohol product, its polymerization degree is 8300, alcoholysis degree 99.9%, dispersity 2.80.
Embodiment 8:
In reactor, feed nitrogen, add 50 parts of soft water, and with 40 parts of vinyl-acetic esters, 0.8 part of Walocel MT 20.000PV, 0.01 part of 2,2'-Azobis(2,4-dimethylvaleronitrile) and 0.02 part of benzoyl peroxide adding reactor, temperature is controlled at 45 ℃, polyreaction 5.5 hours, again the polyvinyl acetate that above-mentioned reaction is obtained be dissolved in 69 parts of methyl alcohol, 7.0 parts of soft water, be made into 24% solution, add 6.0% sodium hydroxide alcoholysis 60 minutes at 20 ℃, get white polyethylene powder alcohol product, its polymerization degree is 5000, alcoholysis degree 99.8%, dispersity 2.70.
Claims (5)
1, a kind of polyvinyl alcohol of high-polymerization degree is characterized in that the polymerization degree is more than 5000.
2, the polyvinyl alcohol of high-polymerization degree according to claim 1 is characterized in that polymerization degree the best is 6000～8000, and dispersity is 1.5～2.8.
3, the polyvinyl alcohol of high-polymerization degree according to claim 2 is characterized in that dispersity the best is 1.8～2.5.
4, the synthesis technique of claim 1,2 or 3 described polyvinyl alcohol of high degree of polymerization is characterized in that may further comprise the steps:
(1) vinyl acetate polyisocyanate polyaddition: adopt suspension polymerization to carry out the vinyl acetate polyisocyanate polyaddition, 10～60 ℃ of polymerization temperatures, polymerization time 2～10 hours;
(2) alcoholysis: polyvinyl acetate is carried out alcoholysis reaction, obtain the polyvinyl alcohol of high-polymerization degree;
Wherein, above-mentioned polymerization system and composed as follows:
The polymerization system of described suspension polymerization is made up of dispersion medium, monomer, dispersion agent, initiator, and its weight percentage is as follows respectively: dispersion medium 40～80%, monomer 20～60%, dispersion agent 0～5%, initiator 0～4%.Its dispersion medium is a soft water, monomer is a vinyl-acetic ester, and dispersion agent is that the vinyl-acetic ester molar content is 0～40% vinyl alcohol-vinyl acetate copolymer, polyacrylic acid an alkali metal salt, acrylic or methacrylic acid or toxilic acid and multipolymer, gelatin, carboxymethyl cellulose or Natvosol and the combination thereof of vinylbenzene or acrylate or methacrylic ester; Initiator is benzoyl peroxide, dilauroyl peroxide, peroxidation trimethylacetic acid tertiary butyl, di-isopropyl peroxydicarbonate, di-cyclohexylperoxy dicarbonate, acetyl peroxide hexanaphthene sulphonyl, Diisopropyl azodicarboxylate, 2,2'-Azobis(2,4-dimethylvaleronitrile) or azo two different pelargonitrile and combinations thereof;
Above-mentioned alcoholysis mode and condition:
0～60 ℃ of described alcoholysis reaction temperature, 0.1～2 hour reaction times; Alcoholysis liquid is made up of the polyvinyl acetate of methyl alcohol, sodium hydroxide, soft water and above-mentioned polymerization gained, and its weight percent is as follows respectively: polyvinyl acetate 2～30%, methyl alcohol 97～65%, sodium hydroxide 1～7%, soft water 0～15%.
5,, it is characterized in that this polyvinyl alcohol of high degree of polymerization is suitable for the high strength high modulus PVA fiber of production intensity greater than 20g/d according to claim 1,2 or 3 described polyvinyl alcohol of high degree of polymerization.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109354641A (en) * | 2014-03-28 | 2019-02-19 | 辛色姆（英国）有限公司 | Prepare the application of the method, branched polymer and the polymer of branched polymer |
| CN110590975A (en) * | 2018-06-12 | 2019-12-20 | 武汉武药科技有限公司 | Medicinal polyvinyl alcohol and preparation method thereof |
| CN111662400A (en) * | 2020-07-06 | 2020-09-15 | 安徽皖维高新材料股份有限公司 | Method for preparing polyvinyl alcohol with high polymerization degree through solution polymerization |
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2003
- 2003-07-09 CN CN 03135392 patent/CN1274726C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109354641A (en) * | 2014-03-28 | 2019-02-19 | 辛色姆（英国）有限公司 | Prepare the application of the method, branched polymer and the polymer of branched polymer |
| CN110590975A (en) * | 2018-06-12 | 2019-12-20 | 武汉武药科技有限公司 | Medicinal polyvinyl alcohol and preparation method thereof |
| CN111662400A (en) * | 2020-07-06 | 2020-09-15 | 安徽皖维高新材料股份有限公司 | Method for preparing polyvinyl alcohol with high polymerization degree through solution polymerization |
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