CN112707976A - Modified polyvinyl alcohol - Google Patents
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- C08J2329/00—Characterised by the use of homopolymers or copolymers 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 an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
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Abstract
The invention belongs to the technical field of polyvinyl alcohol, and particularly relates to modified polyvinyl alcohol. The modified polyvinyl alcohol comprises a monomer unit shown in a formula (I),
in the formula, R1A linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom; r2A linear or branched dialkyl group having 11 to 18 carbon atoms; x+Is a hydrogen atom, a metal ion or an ammonium group; the content of the monomer unit represented by the formula (I) is 0.05 mol% to 10 mol% relative to the total monomer units; the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%. The modified polyvinyl alcohol of the invention has excellent melt processability.
Description
Technical Field
The invention belongs to the technical field of polyvinyl alcohol, and particularly relates to modified polyvinyl alcohol.
Background
Polyvinyl alcohol, also known as PVA, Poval, etc., is a high polymer containing-CH 2-CH (OH) -group in the molecular main chain ("polyvinyl alcohol and its application", Zhang Yi, journal of Huangshan college, Vol.6, No. 3, p.71, left column, No. 1, lines 1-3, published 2004, No. 3, month 06, 30), is a water-soluble polymer which is obtained by alkali alcoholysis of vinyl acetate (PVAC), but a few molecules in the world at present cannot be directly prepared from monomers thereof, and the structural formula is shown as follows.
The polyvinyl alcohol contains a large number of hydroxyl groups in the structure, and the hydroxyl groups have good hydrophilicity, so that the polyvinyl alcohol polymer has good water solubility. Since PVA has unique excellent properties of strong adhesion, oil resistance, smoothness, flexibility of a coating film, solvent resistance, protective colloid property, gas barrier property, wear resistance, water resistance of special treatment and the like, the PVA can be used in the non-fiber field besides the traditional fiber raw material, such as additives for producing coatings, adhesives with strong adhesion capacity, paper processing agents for producing paper products, emulsifying agents, dispersing agents, films with special functions and other products, and the application range of the PVA is distributed in the industries of textiles, foods, medicines, construction, wood processing, paper making, printing, agriculture, high molecular materials and the like ("polyvinyl alcohol and green environmental protection application research thereof", Zhang Jia, the seventh Ningxia younian scientist forum discourse, the left column 417, lines 2, lines 12 to 14 and the 3 rd lines 1 to 8, publication date 2011 year 12 month 01).
As polyvinyl alcohol for the film, a water-soluble polyvinyl alcohol film and the like are known. The polyvinyl alcohol film is colorless and transparent, and has the characteristics of good mechanical strength, smooth surface, low gas transmittance of oxygen and the like, good oil resistance and solvent resistance, no static electricity or dust absorption, good printing performance, wide sources and the like (research progress of the water-soluble polyvinyl alcohol film, afterthought and the like, material guide, No. 23 album 14 in 2009, No. 2 section No. 6-9 in the left column of page 412, published date 11 and 30 days in 2009), and can meet various requirements of various industries on the film, so that development and application hotness is caused at home and abroad (production and application status and prospect of the polyvinyl alcohol film, Wang Jing and the like, plastics, No. 34 and No. 2 in 2005, No. 1 section No. 7-8 in the left column of page 12, published date 2005 and 31 days in 12 months).
For example, patent publication No. CN106795236A discloses a water-soluble modified polyvinyl alcohol comprising specific acrylamide units and lactone ring units, wherein the content ratio of the acrylamide units and the lactone ring units is in a specific range, and a film formed from the modified polyvinyl alcohol is excellent in cold water solubility, mechanical strength and chemical resistance. However, the modified polyvinyl alcohol has poor melt processability, and the difference between the melting temperature and the decomposition temperature is low, so that the direct melt processing is difficult.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a modified polyvinyl alcohol having excellent melt processability.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a modified polyvinyl alcohol comprising a monomer unit represented by the formula (I),
in the formula, R1A linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom; r2A linear or branched dialkyl group having 11 to 18 carbon atoms; x+Is a hydrogen atom, a metal ion or an ammonium group; the content of the monomer unit represented by the formula (I) is 0.05 mol% to 10 mol% relative to the total monomer units; the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%.
The inventor finds that the modified polyvinyl alcohol containing the monomer unit shown in the formula (I) (the content of the monomer unit shown in the formula (I) relative to the whole monomer units is 0.05-10 mol%, the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%) has excellent melt processability in the research process.
Further, the content of the monomer unit represented by the formula (I) is 0.10 mol% to 8 mol% based on the whole monomer units.
Further, the content of the monomer unit represented by the formula (I) is 0.15 to 7 mol% based on the whole monomer units.
Further, the viscosity average polymerization degree of the modified polyvinyl alcohol is 400-2500, and the alcoholysis degree is 84-99.4 mol%.
Further, the viscosity average polymerization degree of the modified polyvinyl alcohol is 500-doped 2000, and the alcoholysis degree is 86 mol% -99.3 mol%.
In the present invention, the total monomer units are the total of the monomer units constituting the modified polyvinyl alcohol.
As the above-mentioned R1Examples of the linear or branched alkyl group having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and n-pentyl groups.
As the above-mentioned R1Excellence inSelected from hydrogen atoms and methyl groups, and more preferably hydrogen atoms.
As the above-mentioned R2Examples of the linear or branched dialkyl hydrocarbon group having 11 to 18 carbon atoms include- (CH)2) 14-、-CH(CH2CH3)-CH2-(CH2)8、-CH(CH3)-CH(CH3)-(CH2)9-、-C(CH3)2-(CH2)10-、 -C(CH3)2-CH(CH3)-(CH2)10Or at said R2When asymmetric, the direction thereof is not particularly limited.
As the above-mentioned R2preferably-C (CH)3)2-(CH2)10-and- (CH)2)14-。
As the above X+Examples of the metal atom include alkali metal atoms (e.g., lithium atom, sodium atom, and potassium atom), alkaline earth metal atoms (e.g., calcium atom), and the like.
As the above X+Examples of the ammonium group include tetramethylammonium group, tetraethylammonium group, tetrapropylammonium group and NH4Monomethyl ammonium group, dimethyl ammonium group, trimethyl ammonium group, etc.
As the above X+Preferably hydrogen atom and alkali metal atom, more preferably hydrogen atom and sodium atom
As the above X+Examples of the ammonium group include tetramethylammonium group, tetraethylammonium group, tetrapropylammonium group and NH4Monomethyl ammonium group, dimethyl ammonium group, trimethyl ammonium group, etc.
X is above+Preferably hydrogen atoms and alkali metal atoms, more preferably hydrogen atoms and sodium atoms.
Examples of the method for copolymerizing a vinyl ester monomer and a monomer providing the monomer unit (I) include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.
Among these methods, the bulk polymerization method carried out in the absence of a solvent and the solution polymerization method carried out using a solvent such as an alcohol are preferable, and the solution polymerization method carrying out polymerization in a lower alcohol is more preferable.
The lower alcohol is preferably an alcohol having 3 or less carbon atoms, more preferably methanol, ethanol, n-propanol, and isopropanol, and still more preferably methanol. When the polymerization reaction is carried out by a bulk polymerization method or a solution polymerization method, the reaction system may be either a batch system or a continuous system.
Examples of the vinyl ester monomer include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate. Among these, vinyl acetate is preferable.
Examples of the initiator used in the polymerization reaction include azo initiators such as 2,2 ' -azobisisobutyronitrile, 2 ' -azobis (2, 4-dimethylvaleronitrile), and 2,2 ' -azobis (4-methoxy-2, 4-dimethylvaleronitrile); and organic peroxide initiators such as benzoyl peroxide, t-butyl peroxypivalate and n-propyl peroxycarbonate. The polymerization temperature at which the polymerization reaction is carried out is not particularly limited, and a range of 5 ℃ to 200 ℃ is suitable.
When a vinyl ester monomer is copolymerized with a monomer that imparts the monomer unit (I), the vinyl ester monomer may be further copolymerized with a copolymerizable monomer within a range that does not impair the effects of the present invention.
Examples of such monomers include α -olefins such as ethylene, propylene, 1-butene, isobutylene and 1-hexene; acrylamide derivatives such as N-methylacrylamide and N-ethylacrylamide; methacrylamide derivatives such as N-methylmethacrylamide and N-ethylmethacrylamide; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, and n-butyl vinyl ether; hydroxyl-containing vinyl ethers such as ethylene glycol vinyl ether, 1, 3-propylene glycol vinyl ether, and 1, 4-butylene glycol vinyl ether; allyl acetate; allyl ethers such as propyl allyl ether, butyl allyl ether, and hexyl allyl ether; a monomer having an oxyalkylene group; isopropenyl acetate; hydroxyl group-containing α -olefins such as 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, and 3-methyl-3-buten-1-ol; silyl group-containing monomers such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, 3- (meth) acrylamidopropyltrimethoxysilane and 3- (meth) acrylamidopropyltriethoxysilane, and the like.
The upper limit of the amount of these monomers to be used varies depending on the purpose of use, application, etc., but is preferably 20 mol%, more preferably 10 mol%, based on the total monomers used in copolymerization.
The vinyl ester copolymer obtained by the above-mentioned method is subjected to alcoholysis in, for example, an alcohol solvent, followed by drying to obtain the modified PVA (A).
In order to obtain the modified PVA (A), it is necessary to set the drying temperature and drying time of the modified PVA (A) resin within a certain range.
Examples of the solvent usable in the alcoholysis reaction include methanol, methyl acetate, and dimethyl sulfoxide. Among these solvents, methanol is preferable.
As catalysts for the alcoholysis of vinyl ester copolymers, it is generally possible to use basic substances.
Examples of the basic substance include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, and alkali metal alkoxides such as sodium methoxide.
The lower limit of the amount of the catalyst used is preferably 0.002, more preferably 0.004 in terms of a molar ratio to the vinyl ester unit of the vinyl ester copolymer.
On the other hand, the upper limit of the amount of the catalyst to be used is preferably 0.2, more preferably 0.1 in terms of a molar ratio to the vinyl ester unit of the vinyl ester copolymer.
The alcoholysis catalyst may be added together at the beginning of the alcoholysis reaction, or a part of the alcoholysis catalyst may be added at the beginning of the alcoholysis reaction, and the remainder may be added during the alcoholysis reaction.
The lower limit of the temperature of the alcoholysis reaction is preferably 5 ℃ and more preferably 20 ℃.
On the other hand, the upper limit of the temperature of the alcoholysis reaction is preferably 80 ℃ and more preferably 70 ℃. The lower limit of the time for the alcoholysis reaction is preferably 5 minutes, and more preferably 10 minutes.
On the other hand, the upper limit of the alcoholysis reaction time is preferably 10 hours, and more preferably 5 hours. The alcoholysis reaction can be carried out by any of a batch type and a continuous type. After the alcoholysis reaction is completed, the residual catalyst may be neutralized as necessary.
Examples of usable neutralizing agents include organic acids such as acetic acid and lactic acid, and ester compounds such as methyl acetate.
After alcoholysis, a washing step of the modified PVA (A) may be carried out as required. As the cleaning solution, a solution containing a lower alcohol such as methanol as a main component and further containing water and/or the same ester such as methyl acetate as that produced in the alcoholysis step can be used.
Subsequently, the washed modified PVA (A) is dried to obtain the modified PVA (A).
As a specific drying method, hot air drying using a cylindrical dryer is preferable. The lower limit of the resin temperature of the modified PVA (A) during drying is preferably 100 ℃ and more preferably 105 ℃.
On the other hand, the upper limit of the resin temperature of the modified PVA (A) during drying is preferably 125 ℃, more preferably 118 ℃, and still more preferably 115 ℃.
The lower limit of the drying time is preferably 2 hours, and more preferably 3 hours.
On the other hand, the upper limit of the drying time is preferably 5 hours, and more preferably 4 hours. The modified pva (a) can be finally obtained by setting the conditions during drying to the above ranges.
When the viscosity average polymerization degree is less than the lower limit, the mechanical strength of the resulting film may be lowered.
The invention also relates to a protective film comprising a modified polyvinyl alcohol comprising monomer units of formula (I),
in the formula, R1A linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom; r2A linear or branched dialkyl group having 11 to 18 carbon atoms; x+Is a hydrogen atom, a metal ion or an ammonium group; the content of the monomer unit shown in the formula (I) relative to the total monomer units of the modified polyvinyl alcohol is 0.05 mol% to 10 mol%; the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%.
Further, the content of the monomer unit represented by the formula (I) is 0.10 mol% to 8 mol% based on the total monomer units of the modified polyvinyl alcohol.
Further, the content of the monomer unit represented by the formula (I) is 0.15 to 7 mol% based on the total monomer units of the modified polyvinyl alcohol.
Further, the viscosity average polymerization degree of the modified polyvinyl alcohol is 400-2500, and the alcoholysis degree is 84-99.4 mol%.
Further, the viscosity average polymerization degree of the modified polyvinyl alcohol is 500-doped 2000, and the alcoholysis degree is 86 mol% -99.3 mol%.
The film of the present invention may contain only the modified PVA, or may be composed of a combination of the modified PVA with a conventional PVA, a saccharide, a plasticizer, an inorganic filler, other additives, and the like.
The film of the present invention is suitable for use as a packaging material for various chemicals such as daily lotions, bleaches, and agricultural chemicals.
The lower limit of the average thickness of the film is preferably 10 μm, more preferably 20 μm, and still more preferably 30 μm. The upper limit of the average thickness of the film is preferably 200 μm, more preferably 150 μm, and still more preferably 120 μm.
When the average thickness of the film is within the above range, the strength of the film is further improved.
On the other hand, when the average thickness of the film is not more than the upper limit, the film can be produced at a lower cost.
In order to improve the blocking resistance of the film, the surface of the film may be roughened by a roll, or anti-blocking powder such as silica or starch may be applied to the film, or embossed, as required.
The roll roughening of the film surface can be performed by forming fine irregularities in advance on a roll with which the film is in contact before drying in film formation.
The embossing treatment is usually performed after forming a film by nipping the film between an embossing roll and a rubber roll while applying heat and pressure.
The anti-blocking effect of the coated powder is large, but it may not be used depending on the application of the film, and therefore, roller texturing and embossing are preferable as the anti-blocking method, and roller texturing is more preferable from the viewpoint of the magnitude of the anti-blocking effect.
The lower limit of the tensile breaking strength of the film is preferably 2.0kg/cm2More preferably 2.1kg/cm2More preferably 2.2kg/cm2。
On the other hand, the upper limit of the tensile breaking strength of the film is not particularly limited, but is, for example, 5.0kg/cm2。
Method for producing film
The method for producing the film is not particularly limited, and the film can be produced by a known method such as a casting method or a melt extrusion method. For example, when the modified PVA and a desired component other than the modified PVA are dissolved in an aqueous solvent (for example, water), the obtained solution is placed on a smooth casting surface, and the aqueous solvent is evaporated and then peeled off from the casting surface, a transparent and uniform film of the present invention can be obtained.
The aqueous solvent is preferably water.
The casting surface may be a smooth and hard material such as steel, aluminum, glass, and polymer (for example, polyolefin, polyethylene, polyamide, polyvinyl chloride, polycarbonate, and polyhalogenated hydrocarbon).
The evaporation rate of the aqueous solvent can be increased by heating the casting surface or exposing the casting surface to heated air, or infrared rays. The casting surface may be flat, and may be a cylindrical casting surface, for example, as in a standard (drum type) casting machine for industrial film formation. The film may be obtained by subsequent oven drying.
The invention has the beneficial effects that:
the modified PVA of the invention has excellent melt processing performance and higher difference between the melting temperature and the decomposition temperature.
The PVA film of the invention has excellent mechanical strength, and the Young modulus is 2.6-3.8Kg/mm2The tensile breaking strength is 2.4-3.1Kg/cm2。
The modified PVA and the film of the present invention are suitable for use as packaging materials for various chemicals such as daily lotions, bleaches, agricultural chemicals and the like.
In the present invention, the degree of viscosity-average polymerization of PVA is measured in accordance with GB/T12010.9-1989 method for measuring the average degree of polymerization of polyvinyl alcohol resin.
In the present invention, the degree of alcoholysis of PVA was measured in accordance with GB/T12010.5-2010 method for measuring residual acetic acid and/or degree of alcoholysis of polyvinyl alcohol resin.
In the present invention, the content of the monomer unit represented by the formula (I) in the modified PVA is determined by the content of the monomer unit represented by the formula (I) in the modified PVA1H-NMR measurement. Specifically, the modified PVA (A) can be dissolved in D2O and used at 600MHz1The H-NMR measuring apparatus was used for measurement at 80 ℃.
In the present invention, the method for measuring the young's modulus and the tensile breaking strength (mechanical strength) is specifically as follows: after conditioning a film having a width of 10mm at 20 ℃ and 65% RH for 1 week, a tensile test was performed using a tensile tester. The interval between the clamps is set to be 50mm, and the stretching speed is set to be 500 mm/min; young's modulus of 2.0kg/mm2Above, tensile breaking strength of 2.0kg/cm2When the above values are satisfied, the product is judged as "A" (good), and the Young's modulus is less than 2.0kg/mm2Or a tensile breaking strength of less than 2.0kg/cm2If it is determined to be "B" (defective).
In the present invention, the method for evaluating the melt processability of the modified PVA specifically comprises: the modified PVA (A) was analyzed for its initial thermal decomposition temperature by thermogravimetric analysis (TGA) and for its melting temperature by Differential Scanning Calorimeter (DSC). A difference between the melting temperature and the thermal decomposition temperature of 50 ℃ or more was judged as "A" (good), and a difference between the melting temperature and the thermal decomposition temperature of less than 35 ℃ was judged as "B" (bad).
Detailed Description
The examples are provided for better illustration of the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.
Example 1
The synthesis of the modified PVA specifically comprises the following steps:
a polymerization vessel (continuous polymerization apparatus) equipped with a reflux condenser, a raw material feeding system, a reaction liquid discharging system, a thermometer, a nitrogen feeding system and a stirring blade was used;
vinyl Acetate (VAC) (630L/hr), methanol (MeOH) (370L/hr), a 20 mass% methanol Solution (SEMA) (122L/hr) of sodium 2-acrylamidotetradecanesulfonate as a modifier, and a 2 mass% methanol solution (AIB) (25L/hr) of 2, 2' -azobisisobutyronitrile were continuously fed into the polymerization vessel by using a metering pump.
Then, the polymerization liquid was continuously taken out from the polymerization vessel so that the liquid level in the polymerization vessel was kept constant. At this time, the polymerization rate of vinyl acetate in the polymerization liquid taken out from the polymerization vessel was adjusted to 40%. The residence time in the polymerization vessel was 4 hours. The temperature of the polymerization liquid taken out of the polymerization vessel was 64 ℃. Unreacted vinyl acetate was removed by taking out the polymerization solution from the polymerization vessel and introducing methanol vapor into the polymerization solution, thereby obtaining a methanol solution (concentration of 35%) of modified polyvinyl acetate (modified PVAc).
The above-described modified PVAc/methanol solution (concentration: 32% by mass) (alcoholysis raw material solution) was fed at 4300L/hr, and the sodium hydroxide/methanol solution (concentration: 7% by mass) (alcoholysis catalyst solution) was fed at 70L/hr (molar ratio of sodium hydroxide to vinyl acetate units in the modified PVAc was 0.01). The feed alcoholysis feed solution is mixed with the alcoholysis catalyst solution using a static mixer. The resulting mixture was placed on a belt and kept at a temperature of 40 ℃ for 18 minutes to conduct alcoholysis. The gel obtained by the alcoholysis reaction is crushed and drained. The obtained modified PVA powder (resin component) was continuously supplied to a dryer at a rate of 600kg/hr (resin temperature: 105 ℃ C.). The average retention time of the powder in the dryer was 4 hours. Thereafter, the PVA was pulverized to obtain a modified PVA. The obtained modified PVA was found to have a viscosity average degree of polymerization of 1550, a degree of alcoholysis of 94 mol% and a content of monomer unit 1 of 3.0 mol%.
The preparation of the film specifically comprises the following steps:
100 parts by mass of the synthesized modified PVA were added with 16 parts by mass of glycerin as a plasticizer, 9 parts by mass of etherified starch as a saccharide, 5 parts by mass of talc having an average particle size of 3 μm as an inorganic filler, 0.8 part by mass of sodium acetate in terms of sodium element, and water to prepare a uniform 8 mass% aqueous solution (water content 92 mass%).
Then, the aqueous solution was cast on a polyester film, dried at room temperature, and peeled from the polyester film to produce a film having an average thickness of 50 μm. The resulting film was further subjected to a heat treatment at 100 ℃ for 10 minutes.
Examples 2 to 3 and comparative examples 1 to 4
Synthesis of PVA
Modified PVA was synthesized in the same manner as in example 1 except for the parameters shown in Table 1.
TABLE 1 parameters for PVA synthesis in examples 2-3 and comparative examples 1-4
Remarking: -means that no such starting material was added.
Manufacture of membranes
Membranes were produced in the same manner as in example 1, except that the modified PVAs synthesized in examples 1 to 3 and comparative examples 1 to 4 shown in Table 2 were used.
The melt processability of the PVA and the mechanical strength (young's modulus and strength) of the film were measured or evaluated for the PVA and the film obtained as described above by the methods described above, and the results are shown in table 2.
Table 2 results of performance testing
Remarking: -indicates that the content is not detected.
As is clear from Table 2, the modified PVAs obtained in examples 1 to 3 had a content of the monomer unit represented by the formula (I) of 2.2 to 2.5 mol% and a PVA melt processability of 52 to 73 ℃. From this, it was confirmed that the modified PVA of the present invention is excellent in melt processability.
As is clear from Table 2, the Young's modulus of the PVA films obtained in examples 1 to 3 was 2.7 to 3.8Kg/mm2The tensile breaking strength is 2.4-3.1Kg/cm2. This proves that the PVA film of the present invention is excellent in mechanical strength.
In conclusion, the modified PVA of the present invention has good melt processability, and the PVA film prepared from the modified PVA has excellent mechanical strength. Therefore, the modified PVA, the resin composition, and the film of the present invention can be suitably used for various packaging materials.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. A modified polyvinyl alcohol characterized by comprising a monomer unit represented by the formula (I),
in the formula, R1A linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom; r2A linear or branched dialkyl group having 11 to 18 carbon atoms; x+Is a hydrogen atom, a metal ion or an ammonium group;
the content of the monomer unit represented by the formula (I) is 0.05 mol% to 10 mol% relative to the total monomer units;
the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%.
2. The modified polyvinyl alcohol according to claim 1, wherein the content of the monomer unit represented by the formula (I) is 0.10 mol% to 8 mol% based on the whole monomer units.
3. The modified polyvinyl alcohol according to claim 2, wherein the content of the monomer unit represented by the formula (I) is 0.15 to 7 mol% based on the whole monomer units.
4. The modified polyvinyl alcohol as claimed in claim 1, 2 or 3, wherein the viscosity average degree of polymerization of the modified polyvinyl alcohol is 400-2500, and the degree of alcoholysis is 84 mol% to 99.4 mol%.
5. The modified polyvinyl alcohol as claimed in claim 4, wherein the viscosity average degree of polymerization of the modified polyvinyl alcohol is 500-2000, and the degree of alcoholysis is 86 mol% to 99.3 mol%.
6. A film characterized by containing a modified polyvinyl alcohol comprising a monomer unit represented by the formula (I),
in the formula, R1A linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom; r2A linear or branched dialkyl group having 11 to 18 carbon atoms; x+Is a hydrogen atom, a metal ion or an ammonium group;
the content of the monomer unit represented by the formula (I) is 0.05 mol% to 10 mol% relative to the total monomer units;
the viscosity average polymerization degree of the modified polyvinyl alcohol is 300-3000, and the alcoholysis degree is 70-99.5 mol%.
7. The film according to claim 6, wherein the content of the monomer unit represented by the formula (I) is 0.10 to 8 mol% based on the whole monomer units of the modified polyvinyl alcohol.
8. The film according to claim 7, wherein the content of the monomer unit represented by the formula (I) is 0.15 to 7 mol% based on the whole monomer units of the modified polyvinyl alcohol.
9. The membrane as claimed in claim 6, 7 or 8, wherein the modified polyvinyl alcohol has a viscosity average degree of polymerization of 400-2500 and a degree of alcoholysis of 84 mol% to 99.4 mol%.
10. The membrane as claimed in claim 9, wherein the modified polyvinyl alcohol has a viscosity average degree of polymerization of 500-2000 and a degree of alcoholysis of 86 mol% to 99.3 mol%.
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| CN201911018310.5A CN112707976A (en) | 2019-10-24 | 2019-10-24 | Modified polyvinyl alcohol |
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| CN201911018310.5A CN112707976A (en) | 2019-10-24 | 2019-10-24 | Modified polyvinyl alcohol |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114014969A (en) * | 2021-11-15 | 2022-02-08 | 上海华峰新材料研发科技有限公司 | Water-soluble polymer and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114014969A (en) * | 2021-11-15 | 2022-02-08 | 上海华峰新材料研发科技有限公司 | Water-soluble polymer and preparation method and application thereof |
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