JP2001019720A - Vinyl alcohol polymer - Google Patents

Abstract

(57) [Problem] An object of the present invention is to provide a water-soluble vinyl alcohol-based polymer having a poly (oxyalkylene) group in a side chain. An object of the present invention is to provide a compound represented by the general formula (1): (Wherein R ₁ represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, R ₂ represents a hydrogen atom or an organic residue,
X represents hydrogen or an alkali metal atom such as sodium or potassium, and n represents an integer of 1 to 100. This is achieved by a vinyl alcohol polymer containing 0.01 to 15 mol% of a monomer unit having a poly (oxyalkylene) group represented by the formula (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel vinyl alcohol-based polymer.

[0002]

2. Description of the Related Art Vinyl alcohol polymers (hereinafter referred to as PVA)
Abbreviations) are used as stabilizers for paper processing, fiber processing and emulsions because of their excellent interfacial properties and strength properties as a few crystalline water-soluble polymers, as well as PVA-based films and PVA-based polymers. It occupies an important position as a raw material for fibers and the like. On the other hand, the pursuit of high functionality by controlling the crystallinity or improving the specific performance by introducing a functional group has been pursued, and various modified PVAs have been developed.

[0003] PV having a poly (oxyalkylene) group
A is a known substance, for example, as disclosed in JP-A-59-1554.
No. 08, such as poly (oxyalkylene) having an allyl group at the terminal or a (meth) acrylic acid ester of poly (oxyalkylene) or (meth) acrylamide having a poly (oxyalkylene) group on a nitrogen atom;
A method for synthesizing a poly (oxyalkylene) group-containing PVA by saponifying a copolymer of a poly (oxyalkylene) group-containing compound having an unsaturated bond and a vinyl ester is disclosed. However, in these, when the amount of the side chain alkyl group in the poly (oxyalkylene) group increases, the water solubility decreases due to the hydrophobicity of the alkyl group, and PVA may not be dissolved in water. In addition, in the copolymerization of a poly (oxyalkylene) group having an allyl group and a vinyl ester, the reaction rate during polymerization is greatly reduced, and the degree of polymerization of the obtained polymer is greatly reduced in accordance with the amount of copolymerization. There is a problem that the degree of polymerization of the PVA which can be synthesized and the content of the poly (oxyalkylene) group are narrow. Furthermore, in the copolymerization of an allyl monomer and a vinyl ester, a large amount of the allyl monomer remains in the polyvinyl acetate after polymerization because the monomer reactivity ratio of the allyl group and the vinyl ester is close. In addition, it is not industrially preferable that the saponified PVA needs to be washed with a large amount of solvent in order to remove it. There is no problem at the time of polymerization as described above for the copolymerization of a (meth) acrylic acid ester of a poly (oxyalkylene) group with a vinyl ester, but in the step of saponifying the obtained copolymer to form PVA, Since the poly (oxyalkylene) group is eliminated by hydrolysis of the ester group, there is a problem that a poly (oxyalkylene) group only for the purpose cannot be introduced into PVA. In the case of a (meth) acrylamide having a poly (oxyalkylene) group on a nitrogen atom, there is no problem with copolymerization with a vinyl ester as in the case of a (meth) acrylic ester, but an attempt was made to obtain PVA having a high degree of saponification. In this case, there is a problem of elimination of a poly (oxyalkylene) group due to hydrolysis at the saponification stage, as in the case of (meth) acrylic acid ester, and there is a difficulty in supplying such a monomer, which is not practical.

[0004]

An object of the present invention is to provide a novel vinyl alcohol polymer having a poly (oxyalkylene) group in a side chain.

[0005]

Means for Solving the Problems The present inventors have conducted studies in view of the above-mentioned problems, and as a result, have found that vinyl containing a monomer unit having a poly (oxyalkylene) group represented by the general formula (1). Successful synthesis of an alcohol-based polymer led to the completion of the present invention.

[0006]

Embedded image (Wherein R ₁ represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, R ₂ represents a hydrogen atom or an organic residue,
X represents hydrogen or an alkali metal atom such as sodium or potassium, and n represents an integer of 1 to 100. )

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The content of a monomer unit having a poly (oxyalkylene) group in the PVA of the present invention is as follows:
0.01 to 15 mol% is necessary, and preferably 0.0 to 15 mol%.
3 to 15 mol%, more preferably 0.05 to 1 mol%.
0 mol%. When the content of the monomer unit having a poly (oxyalkylene) group is less than 0.01 mol%, physical properties and functions based on the poly (oxyalkylene) group are not sufficiently exhibited, and more than 15 mol%. in case of,
It is not preferable because characteristics such as water solubility and crystallinity inherent to the vinyl alcohol polymer are lost.

The content of the monomer unit having a poly (oxyalkylene) group in the PVA of the present invention is 50%.
More preferably, the amount is not more than part by weight. When the content of the monomer unit having a poly (oxyalkylene) group exceeds 50 parts by weight, characteristics of PVA such as water solubility and crystallinity may be impaired.

The degree of polymerization of the PVA of the present invention is not particularly limited, but the viscosity average degree of polymerization (hereinafter simply referred to as degree of polymerization) calculated from the intrinsic viscosity of the PVA at 30 ° C. (measured with an Ostwald viscometer). There is)
The range of 50 to 10,000 is preferable, and 100 to 8000
Is more preferable, the range of 150-5000 is still more preferable, and the range of 200-3000 is especially preferable.
If the degree of polymerization exceeds 10,000, it is difficult to synthesize, and if the degree of polymerization is lower than 50, P
It is not preferable because the properties of VA no longer appear.

The degree of saponification of the PVA of the present invention is not particularly limited as long as it is water-soluble, but is usually 70 mol% or more and 99.9.
It is less than 9 mol%, preferably from 75 mol% to less than 99.9 mol%, more preferably from 80 mol% to less than 99.7 mol%, particularly preferably from 85 mol% to less than 99.5 mol%.

The PVA of the present invention substantially comprises a vinyl alcohol unit or a vinyl alcohol unit and a vinyl ester unit except for a monomer unit having a poly (oxyalkylene) group. Examples of the vinyl ester unit include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl trifluoroacetate, and vinyl 2-ethylhexanoate, and usually vinyl acetate is used.

[0012] Further, it may be free from other monomer units as long as the gist of the present invention is not impaired. Examples of such a unit include olefins such as ethylene, propylene, 1-butene, and isobutene; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, and itaconic acid; 1-18 mono- or dialkyl esters; acrylamide, C1-C18 N-alkylacrylamide, N, N-dimethylacrylamide, 2-
(N-acrylamide) -2-methylpropanesulfonic acid and salts thereof, acrylamides such as acrylamidopropyldimethylamine or acid salts or quaternary salts thereof; methacrylamide, N-alkyl methacrylamide having 1 to 18 carbon atoms, N Methacrylamides such as N, N-dimethylmethacrylamide, 2-methacrylamido-2-methylpropanesulfonic acid and salts thereof, methacrylamidopropyldimethylamine or acid salts or quaternary salts thereof; N-vinylpyrrolidone, N-vinyl N-vinylamides such as formamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyls Vinyl ethers such as ether;
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinylsilanes such as trimethoxyvinylsilane; allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol; However, the present invention is not limited to this. Although the content of these monomer units is not particularly limited, the content of these components is usually set to 10 mol% or less so as not to impair the features realized by the poly (oxyalkylene) group, % Or less is more preferable.

As a method for synthesizing the modified PVA having a poly (oxyalkylene) group of the present invention, a vinyl ester monomer usually used for synthesizing a PVA-based copolymer and a poly (oxyalkylene) represented by the general formula (2) are used. ) A method of saponifying a copolymer of a monomer having a group is used.

[0014]

Embedded image (Wherein R ₁ represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, R ₂ represents a hydrogen atom or an organic residue,
X represents hydrogen or an alkali metal atom such as sodium or potassium, and n represents an integer of 1 to 100. )

Which corresponds to a poly (oxyalkylene) group;
The repeating structure represented by (OR _1- ) _n- has the following structure. That is, the alkylene group having 2 to 4 carbon atoms or the substituted alkylene group represented by R ₁ may be different for each oxyalkylene unit, and these oxyalkylene groups may be bonded in blocks or randomly. Among them, those in which R ₁ is only ethylene, only propylene, only butylene, or a mixture of two or three of these are preferably used from the viewpoint of supply.

Among the substituents represented by R ₂ , the organic residue specifically includes a linear, branched or cyclic alkyl group having 18 or less carbon atoms, a phenyl group and an alkylphenyl group. Among these, those in which R ₂ is hydrogen, a methyl group or an n-butyl group are preferably used.

Examples of such a monomer unit having a poly (oxyalkylene) group include methyl-2- (2-
(Hydroxyethoxy) methyl acrylate, ethyl-2
-(2-hydroxyethoxy) methyl acrylate, butyl-2- (2-hydroxyethoxy) methyl acrylate, 2-ethylhexyl-2- (2-hydroxyethoxy) methyl acrylate, methyl-2- (2-hydroxypropoxy) methyl acrylate , Ethyl-2-
(2-hydroxypropoxy) methyl acrylate, butyl-2- (2-hydroxypropoxy) methyl acrylate, 2-ethylhexyl-2- (2-hydroxypropoxy) methyl acrylate, methyl-2- (ω-hydroxypolyethyleneglycoxy) methyl Acrylate, ethyl-2- (ω-hydroxypolyethyleneglycoxy) methyl acrylate, butyl-2- (ω-hydroxypolyethyleneglycoxy) methyl acrylate, 2
-Ethylhexyl-2- (ω-hydroxypolyethyleneglycoxy) methyl acrylate, methyl-2- (ω-
(Hydroxypolypropyleneglycoxy) methyl acrylate, ethyl-2- (ω-hydroxypolypropyleneglycoxy) methylacrylate, butyl-2- (ω-hydroxypolypropyleneglycoxy) methylacrylate, 2-ethylhexyl-2- (ω-hydroxypolypropyleneglycol) Xy) methyl acrylate, methyl-2
-(2-methoxyethoxy) methyl acrylate, ethyl-2- (2-methoxyethoxy) methyl acrylate, butyl-2- (2-methoxyethoxy) methyl acrylate, 2-ethylhexyl-2- (2-methoxyethoxy) methyl acrylate , Methyl-2- (2-methoxypropoxy) methyl acrylate, ethyl-2-
(2-methoxypropoxy) methyl acrylate, butyl-2- (2-methoxypropoxy) methyl acrylate, 2-ethylhexyl-2- (2-methoxypropoxy) methyl acrylate, methyl-2- (ω-methoxypolyethyleneglycoxy) methyl Acrylate, ethyl-2- (ω-methoxypolyethyleneglycoxy) methyl acrylate, butyl-2- (ω-methoxypolyethyleneglycoxy) methyl acrylate, 2-ethylhexyl-2- (ω-methoxypolyethyleneglycoxy) methyl acrylate, methyl -2- (ω-methoxypolypropyleneglycoxy) methyl acrylate, ethyl-2-
(Ω-methoxypolypropyleneglycoxy) methyl acrylate, butyl-2- (ω-methoxypolypropyleneglycoxy) methyl acrylate, 2-ethylhexyl-2- (ω-methoxypolypropyleneglycoxy) methyl acrylate, methyl-2- (2- n-butoxyethoxy) methyl acrylate, ethyl-2- (2-n-butoxyethoxy) methyl acrylate, butyl-2-
(2-n-butoxyethoxy) methyl acrylate, 2
-Ethylhexyl-2- (2-n-butoxyethoxy)
Methyl acrylate, methyl-2- (2-n-butoxypropoxy) methyl acrylate, ethyl-2- (2-
n-butoxypropoxy) methyl acrylate, butyl-2- (2-n-butoxypropoxy) methyl acrylate, 2-ethylhexyl-2- (2-n-butoxypropoxy) methyl acrylate, methyl-2- (ω-n
-Butoxypolyethyleneglycoxy) methyl acrylate, ethyl-2- (ω-n-butoxypolyethyleneglycoxy) methyl acrylate, butyl-2- (ω-n-
Butoxypolyethyleneglycoxy) methyl acrylate, 2-ethylhexyl-2- (ω-n-butoxypolyethyleneglycoxy) methyl acrylate, methyl-2
-(Ω-n-butoxypolypropyleneglycoxy) methyl acrylate, ethyl-2- (ω-n-butoxypolypropyleneglycoxy) methyl acrylate, butyl-
2- (ω-n-butoxypolypropyleneglycoxy) methyl acrylate, 2-ethylhexyl-2- (ω-n
-Butoxypolypropyleneglycoxy) methyl acrylate, methyl-2- (2-phenoxyethoxy) methyl acrylate, ethyl-2- (2-phenoxyethoxy) methyl acrylate, butyl-2- (2-phenoxyethoxy) methyl acrylate, 2- Ethylhexyl-2- (2-phenoxyethoxy) methyl acrylate, methyl-2- (2-phenoxypropoxy) methyl acrylate, ethyl-2- (2-phenoxypropoxy) methyl acrylate, butyl-2- (2-phenoxypropoxy) methyl Acrylate, 2-ethylhexyl-2- (2-phenoxypropoxy) methyl acrylate, methyl-2- (ω-phenoxypolyethyleneglycoxy) methyl acrylate, ethyl-2- (ω-phenoxypolyethyleneglycol) Coxy) methyl acrylate,
Butyl-2- (ω-phenoxypolyethyleneglycoxy) methyl acrylate, 2-ethylhexyl-2-
(Ω-phenoxypolyethyleneglycoxy) methyl acrylate, methyl-2- (ω-phenoxypolypropyleneglycoxy) methyl acrylate, ethyl-2- (ω
-Phenoxypolypropyleneglycoxy) methyl acrylate, butyl-2- (ω-phenoxypolypropyleneglycoxy) methyl acrylate, 2-ethylhexyl-2- (ω-phenoxypolypropyleneglycoxy) methyl acrylate, 2- (2-hydroxyethoxy) methyl Acrylic acid and its salt, 2- (2-hydroxypropoxy) methylacrylic acid and its salt, 2- (2-n-
Butoxyethoxy) methyl acrylic acid and its salts, 2-
(Ω-hydroxypolyethyleneglycoxy) methylacrylic acid and its salt, 2- (ω-hydroxypolypropyleneglycoxy) methylacrylic acid and its salt, 2- (ω
-N-butoxypolyethyleneglycoxy) methylacrylic acid and salts thereof, but are not limited thereto.

The number n of the oxyalkylene group units shown in the general formula (2) is usually from 1 to 100, and from 2 to 80
Is preferable, and it is more preferable that it is 3-50. Poly (oxyalkylene) group-containing monomers in which n exceeds 100 are difficult to synthesize and difficult to supply, and are not practical.

Examples of the method of copolymerizing the vinyl ester monomer with a comonomer having a poly (oxyalkylene) group include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Above all, a bulk polymerization method or a solution polymerization method in which polymerization is carried out without a solvent or in a solvent such as an alcohol is usually employed, and when a polymer having a high degree of polymerization is obtained, an emulsion polymerization method is employed. When a solvent is used at the time of solution polymerization, methyl alcohol, ethyl alcohol, propyl alcohol and the like are used as alcohols, and dimethyl sulfoxide, tetrahydrofuran and the like are used as other organic solvents, but are not limited thereto. Two or more of these solvents may be mixed and used as a polymerization solvent. Examples of the initiator used for the copolymerization include α, α′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, and n-propylperoxycarbonate. And other known initiators such as azo initiators and peroxide initiators. The polymerization temperature is not particularly limited, but is preferably in the range of -10C to 150C.

For hydrolysis subsequent to copolymerization, the technique of alkali saponification or acid saponification used in saponification of ordinary polyvinyl esters can be applied as it is. That is,
In the case of alkali saponification, a basic catalyst such as sodium hydroxide, potassium hydroxide or sodium methylate is used, and in the case of acid saponification, an acidic catalyst such as mineral acid or p-toluenesulfonic acid is used to form methanol, ethanol, propanol, or butanol. The reaction is carried out using alcohols such as ethylene glycol and the like, glycols, esters such as methyl acetate, dimethyl sulfoxide, diethylene glycol dimethyl ether and the like as solvents. There is no problem even if solvents such as tetrahydrofuran, dioxane, toluene, and acetone are appropriately mixed and used in order to improve the solubility of the vinyl ester polymer and the catalyst. In some cases, a radical polymerization inhibitor such as hydroquinone or p-methoxyphenol may be added. The conditions of the saponification reaction are appropriately adjusted depending on the structure of the vinyl ester polymer to be used and the degree of saponification of the intended vinyl alcohol polymer. Usually, saponification is carried out at a catalyst concentration / vinyl ester unit concentration (molar ratio) = 0.
001-5.0, reaction temperature: 20-180 ° C., reaction time: 0.1-20 hours.

In the PVA having a poly (oxyalkylene) group of the present invention, the presence of a carboxyl group in the monomer unit having a poly (oxyalkylene) group represented by the general formula (1) is essential. This carboxyl group improves the water solubility of PVA as a carboxylic acid or a salt thereof in PVA, thereby obtaining a water-soluble PVA having a poly (oxyalkylene) group which was conventionally insoluble in water. Can be done.

The vinyl alcohol polymer of the present invention can be used for film, sheet, pipe, separation membrane, fiber, sizing agent for fiber, fiber treatment agent, fiber processing agent, sizing agent for fiber product, paper clear coating, paper pigment Coating agents, internal sizing agents for paper, paper processing agents such as binders for overcoating thermal paper, dispersants for organic and inorganic pigments, polymerization dispersion stabilizers for emulsions, polymerization dispersion stabilizers for PVC, addition of mortar and cement Adhesives, pressure-sensitive adhesives, anti-fog agents, paints, adhesives for paper, wood, plastics, etc., binders for nonwoven fabrics, binders for fibers, binders for ceramics, binders for various building materials such as gypsum board and fiberboard, hot melt bonding Agent, image forming material, photosensitive resin, base material for gel, raw material for polyvinyl acetal such as formal resin and butyral resin, molding (Film, fibers, sheets, tubes, nonwovens, etc.), can be used for soil improvement agent.

[0023]

The present invention will be described in detail below with reference to examples and comparative examples. In the following Examples and Comparative Examples, “parts” and “%” mean on a weight basis unless otherwise specified.

Example of Modified PVA Having Poly (oxyalkylene) Group Example 1 2000 g of vinyl acetate monomer was placed in a 5 L reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet and a thermometer.
Poly (oxyalkylene) group-containing monomer (monomer 1)
12 g and 500 g of methanol were charged, and nitrogen gas was bubbled for 30 minutes to degas. Further, a comonomer solution having a concentration of 30% was prepared by dissolving Monomer 1 in methanol as a delay solution, and nitrogen was replaced by bubbling with nitrogen gas. When the internal temperature of the reactor was raised to 60 ° C., 0.4 g of 2,2′-azobis (isobutyronitrile) was added to initiate polymerization. While the delay solution was added dropwise to keep the monomer composition (the ratio of vinyl acetate to monomer 1) in the polymerization solution constant, polymerization was carried out at 60 ° C. for 5 hours, followed by cooling to stop the polymerization. The total amount of the comonomer solution added by delay before stopping the polymerization was 440 mL. Further, the solid content concentration at the time of termination of the polymerization was 25.1%. Subsequently, unreacted vinyl acetate monomer was removed while occasionally adding methanol at 30 ° C. under reduced pressure to obtain a methanol solution of polyvinyl acetate copolymer (concentration: 35%). A part of the methanol solution was put into ether to recover the polymer, which was purified by reprecipitation twice with acetone-hexane, and then dried at 40 ° C. under reduced pressure.
This purified polymer, and a CDCl ₃ solvent 5
00 MHz ¹ H-NMR (GX-50 manufactured by JEOL)
0) As a result of the measurement, a signal derived from an α-methylene proton in a monomer unit having a poly (oxyalkylene) group was observed in a range of 2.5 to 2.8 ppm. Comparing the integrated value of this signal and the signal derived from polyvinyl acetate (4.8 to 5.2 ppm), the amount of modification of the monomer unit derived from monomer 1 in the polymer was 1.0 mol%. I found it to be. Measurement of intrinsic viscosity in acetone at 30 ° C (measured with Ostwald viscosity tube)
Was carried out and the viscosity average degree of polymerization was calculated. As a result, the viscosity average degree of polymerization was 1650.

In a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, and a thermometer, 100 parts of the methanol solution (concentration: 30.0%) of the vinyl acetate copolymer obtained above was weighed, and the mixture was heated to 40 ° C. Then, 3.5 parts of a 10% strength methanol solution of sodium hydroxide was added to perform saponification. After leaving at 40 ° C. for 1 hour, pulverized, neutralized by adding acetic acid, and repeatedly washed by boiling in a methanol bath having a bath ratio of 3 for 1 hour, and then dried at 60 ° C. for 20 hours or more to obtain a poly ( A modified PVA having an (oxyalkylene) group was obtained.
This PVA is referred to as PVA1. Proton NMR of PVA1
_(D 6 -DMSO) was measured, 2.5 to 2.8
A signal derived from an α-methylene proton in a monomer unit having a poly (oxyalkylene) group in the ppm range was observed. Comparing the integrated value of this signal with a signal derived from polyvinyl alcohol (3.8 to 4.2 ppm) and a signal derived from polyvinyl acetate (4.8 to 5.2 ppm), 1.0 mol% in the polymer was obtained. The introduction of a poly (oxyalkylene) group was confirmed. Also, P
From the NMR chart of VA1, no peak (5.8 to 6.4 ppm) derived from the olefin bond of monomer 1 was observed, and it was confirmed that monomer 1 did not remain in PVA1. The intrinsic viscosity was measured (measured with an Ostwald viscometer) at 30 ° C. using an aqueous solution of PVA1 to calculate the viscosity average degree of polymerization.
600. When the degree of saponification of the vinyl alcohol polymer was measured in accordance with JIS-K6726, P
The degree of saponification of VA1 was 98.5 mol%. PVA1
Was dissolved in distilled water to make a 4% concentration aqueous solution.
When the state of the solution at ° C was visually observed, PVA was completely dissolved and the solution was colorless and transparent. When the temperature of the solution was changed within the range of 10 ° C. to 90 ° C. and the state of the solution was observed, the solution was always colorless and transparent within this temperature range, and no cloud point was observed.

Examples 2 to 10 The same as Example 1 except that the poly (oxyalkylene) group-containing monomer shown in Table 1 was changed, the polymerization conditions shown in Table 2 were changed, and the saponification conditions shown in Table 3 were changed. PVA by method
2-PVA10 was synthesized. Obtained PVA1 to PVA
Table 4 shows the analysis results and water solubility of No. 10.

Comparative Examples 1 to 5 The polymerization conditions shown in Table 2 were changed, for example, the poly (oxyalkylene) group-containing monomer shown in Table 1 was changed, the comonomer solution was not sequentially added during copolymerization, and the saponification shown in Table 3. Except for changing the conditions, vinyl alcohol polymers PVA11 to PVA15 were obtained in the same manner as in Example 1. P obtained
Table 4 shows the physical properties and water solubility of VA11 to PVA15.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

As shown in Table 4, good water solubility at 20 ° C. and no cloud point at a temperature of 10 ° C. to 90 ° C. satisfy the conditions of the present invention. If not included in the range, the performance is poor in either or both of the water solubility at 20 ° C. and the cloud point.
No residual monomer was found in any of the PVAs of the examples, but in many of the PVAs of the comparative examples, residual monomers were found as impurities in the PVA.

Comparison between Example 1 and Comparative Example 2 The poly (oxyalkylene) group having the same structure is modified in the same amount, but in Example 1, the water content is changed due to the carboxylic acid (salt) group contained in the monomer unit. 10-90 ° C
The aqueous solution was always colorless and transparent in the temperature range of Comparative Example 2, whereas the aqueous solution was bluish at 20 ° C and cloudy at 30 ° C in Comparative Example 2 because no carboxylic acid (salt) was contained. Point.

Comparison between Example 6 and Comparative Example 3 The poly (oxyalkylene) group having the same structure is modified in an equal amount. In Example 6, the aqueous solution is always colorless and transparent in the temperature range of 10 ° C. to 90 ° C. On the other hand, in Comparative Example 3, although a colorless and transparent aqueous solution was obtained at 20 ° C., when this aqueous solution was heated to 80 ° C., a cloud point was formed and the solution became cloudy.

Comparison of Example 8 with Comparative Example 4 and Comparison of Example 9 with Comparative Example 5 Poly (oxyalkylene) groups having the same structure were modified in equal amounts. In the temperature range of 90 ° C., the aqueous solution was always colorless and transparent, whereas in Comparative Examples 4 and 5, the solution was cloudy even at 20 ° C., and the solution was always cloudy in the temperature range of 10 ° C. to 90 ° C. Water solubility was a bad result.

[0036]

The vinyl alcohol polymer of the present invention is
Since it has a carboxylic acid (or a salt thereof) group together with a poly (oxyalkylene) group, the poly (oxyalkylene) group, which has been insoluble in water, retains the water solubility of PVA and is highly useful. . Further, since it has a poly (oxyalkylene) group, the glass transition point is low, and for example, when formed into a film, a flexible film can be obtained even at a low temperature. In addition, since the thermal stability of PVA is improved by the poly (oxyalkylene) group, it can be suitably used for purposes such as melt molding. In addition, because it also has the inherent properties of PVA, known uses of PVA, such as films, sheets, pipes, separation membranes, fibers, sizing agents for fibers,
Paper processing agents such as fiber treatment agents, fiber processing agents, sizing agents for textile products, clear coating agents for paper, pigment coating agents for paper, internal sizing agents for paper, binders for overcoating of thermal paper, organic and inorganic pigments Dispersants, polymerization dispersion stabilizers for emulsions, polymerization dispersion stabilizers for PVC, mortar and cement additives, pressure-sensitive adhesives, antifogging agents, paints, adhesives for paper, wood and plastics, binders for nonwoven fabrics, Fiber binder, ceramic binder,
Binders for various building materials such as gypsum board and fiberboard, hot melt adhesives, image forming materials, photosensitive resins, base materials for gels, raw materials for polyvinyl acetal such as formal resins and butyral resins, molded products (films, fibers, sheets) , Tubes, nonwoven fabrics, etc.), soil conditioners and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J027 AC02 AC03 AC04 BA04 CB03 CB09 CD08 CD09 4J100 AD02P AG02P AG03P AG04P AG06P AG08P AJ03Q AK08Q BA02Q BA03Q BA08Q BB18P CA04 HA08 HB39 HC12 HC71 JA15 JA13 JA13 JA13 JA13

Claims (2)

[Claims] 1. A vinyl alcohol polymer comprising 0.01 to 15 mol% of a monomer unit having a poly (oxyalkylene) group represented by the general formula (1). Embedded image (Wherein R ₁ represents an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, R ₂ represents a hydrogen atom or an organic residue,
X represents hydrogen or an alkali metal atom such as sodium or potassium, and n represents an integer of 1 to 100. ) 2. The vinyl alcohol-based polymer according to claim 1, wherein the content of the monomer unit having a poly (oxyalkylene) group represented by the general formula (1) in the vinyl alcohol-based polymer is 50 parts by weight or less. Coalescing.