JP4531538B2 - Polyvinyl alcohol resin and use thereof - Google Patents

Description

  The present invention relates to a novel polyvinyl alcohol-based resin having a carboxyl group-containing alkyl group in a side chain and its use, and more specifically, viscosity stability of aqueous solution, high-speed coating property, reactivity with a crosslinking agent, and film. It is related with the polyvinyl alcohol-type resin which is excellent in water solubility, and can control these characteristics with pH, and its use.

Conventionally, polyvinyl alcohol resins (hereinafter, polyvinyl alcohol is abbreviated as PVA) are dispersed using their excellent water solubility, interface properties, film properties (film forming properties, strength, oil resistance, etc.), etc. Widely used in agents, emulsifiers, suspending agents, fiber processing agents, paper processing agents, binders, adhesives, films and the like.
Such PVA-based resins have been tried to be modified according to the purpose of use, and modified PVA in which various functional groups are introduced into the side chain by copolymerization is marketed. Among them, modified PVA in which a carboxyl group is introduced into a side chain is widely used as a fiber processing agent and a paper processing agent. This carboxyl group-modified PVA is produced by copolymerizing an ethylenically unsaturated carboxylic acid such as acrylic acid, maleic acid, and itaconic acid with a vinyl ester compound, and then saponified. Compared with unmodified PVA When used as a paper processing agent, it is excellent in water solubility, viscosity stability of aqueous solution, flow characteristics under high shear rate, and chelate-forming ability with metal ions (for example, see Non-Patent Document 1). It is known that the reaction with the sulfuric acid band in the paper yields efficiently on the surface and provides excellent barrier properties.
POLYVINYL ALCOHOL-DEVELOPMENTS, Edited by C.I. A. FINCH, 1992, p157

  However, since the carboxyl group-modified PVA described in Non-Patent Document 1 described above tends to form a lactone ring by the reaction of the carboxyl group with an adjacent hydroxyl group, a part of the carboxyl group introduced by copolymerization becomes inactive, In addition, if the modification ratio is increased to improve the characteristics, the amount of hydroxyl group may be reduced due to lactone ring formation, or water solubility, which is an inherent characteristic of PVA resin, may be impaired due to intermolecular crosslinking. there were. In other words, in recent years, it has been impossible for such carboxyl group-modified PVA to cope with the further surface strength required in paper processing applications and the demand for reducing the amount used, and a modified PVA-based resin instead Is required.

  However, as a result of intensive studies in view of such circumstances, the present inventors have found that a PVA-based resin having a carboxyl group-containing alkyl group in the side chain meets the above purpose, and completed the present invention.

（式中、Ｒ ^３は水素原子、アルキル基、アリル基またはアルカリ金属を示す。）
PVA-based resin having a carboxyl group containing alkyl group in such a side chain, Ru PVA resin der containing a structural unit represented by the general formula (1).

(Wherein, R ³ is a hydrogen atom, an alkyl group, indicates to an allyl group or an alkali metal.)

The PVA-based resin containing a structural unit having a carboxyl group-containing alkyl group in the side chain represented by the general formula (1) of the present invention is excellent in the viscosity stability of aqueous solution and high-speed coating property. Since it has excellent chelate-forming ability and reactivity with various crosslinking agents, it is suitably used for paper processing agents, water-resistant coating agents (particularly resins for protective layers of heat-sensitive recording media), adhesives and the like. Further, it is excellent in water solubility when formed into a molded product, particularly a film, and is effective as a water-soluble film for packaging of agricultural chemicals, detergents, laundry clothes, civil engineering additives, bactericides, dyes, pigments and the like. In addition, the PVA-based resin becomes a hydrogel by acidifying the pH of the aqueous solution, and in this case, an organic compound mixed in the aqueous solution is taken into the gel, and therefore used as a separation and recovery agent for various organic compounds. It is also possible. Furthermore, the PVA-based resin of the present invention is effective for various uses, particularly for uses such as an adhesive, an emulsifier, a suspending agent, and a fiber processing agent, using the characteristics.

Hereinafter, the present invention will be described in detail.
The PVA resin of the present invention has a carboxyl group-containing alkyl group in the side chain, and more specifically is a PVA resin having a structural unit represented by the following general formula (1).

上記一般式（１）において、Ｒ ^３は水素原子、アルキル基、またはアルカリ金属を示し、該アルキル基としては特に限定されないが、例えばメチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｔｅｒｔ−ブチル基、オクチル基、ベフェニル基等が好ましく、該アルカリ金属としてはナトリウム、カリウムが好ましい。

In the general formula (1) , R ³ represents a hydrogen atom, an alkyl group, or an alkali metal, and the alkyl group is not particularly limited, but for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n- A butyl group, an isobutyl group, a tert-butyl group, an octyl group, a bephenyl group and the like are preferable, and sodium and potassium are preferable as the alkali metal .

一般式（２）で示される化合物としては、ウンデシレン酸およびそのエステル、塩等の誘導体が挙げられ、中でも入手の容易さや良好な共重合性を有する点で、特にＲ^３が水素であるウンデシレン酸が好ましい。
In obtaining such a PVA-based resin, although not particularly limited, a method of saponifying a copolymer of a vinyl ester monomer and a compound represented by the following general formula (2) is preferably used.

The the compound represented by the general formula (2), undecylenic acid AND ITS esters include derivatives such as salts, in that it has among others ease and good copolymerizability of availability, R ³ especially hydrogen der Undecylenic acid is preferred.

  Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, Examples include vinyl versatate. Of these, vinyl acetate is preferably used from the economical viewpoint.

Further, in the present invention, in addition to the above copolymerization component, other monomers can be copolymerized in an amount of about 0.1 to 20 mol% within a range not impairing the object of the present invention. For example, ethylene, Α-olefins such as propylene, isobutylene, α-octene, α-dodecene, α-octadecene, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, or salts thereof or mono Or dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, or salts thereof, alkyl vinyl ether , Dimethylallyl vinyl ketone , N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxyalkylene (meth) allyl ethers such as polyoxypropylene (meth) allyl ether, polyoxyethylene (meth) acrylate, poly Polyoxyalkylene (meth) acrylates such as oxypropylene (meth) acrylate, polyoxyethylene (meth) acrylamide, polyoxyalkylene (meth) acrylamides such as polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) (Acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, poly Examples include reoxyethylene vinylamine and polyoxypropylene vinylamine.
Furthermore, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 2-hydroxy-3- Cationic group-containing monomers such as methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3-butenetrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, acetoacetyl group-containing monomers 3,4-diacetoxy-1- Ten, 1,4-diacetoxy-2-butene, ethylene carbonate, vinyl ethylene carbonate, glycerin monoallyl ether, isopropenyl acetate, also 1-methoxy-vinyl acetate, and the like.

  Among them, an α-olefin-vinyl alcohol copolymer obtained by using α-olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene and the like as a copolymerization component is improved in emulsifying power and aqueous solution. It is preferable in terms of viscosity stability, and the preferable content of the α-olefin is 0.1 to 20 mol% (more preferably 2 to 10 mol%).

The method for copolymerizing the above vinyl ester monomer and the compound represented by the general formula (2) (and other monomers) is not particularly limited, and includes bulk polymerization, solution polymerization, suspension polymerization, A known method such as dispersion polymerization or emulsion polymerization can be employed, but solution polymerization is usually performed.
The method for charging the monomer component at the time of copolymerization is not particularly limited, and any method such as batch charging, split charging, continuous charging, etc. may be employed.
Examples of the solvent used in such copolymerization include usually lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propanol and butanol, and ketones such as acetone and methyl ethyl ketone, and industrially preferred is methanol. used.
The amount of the solvent used may be appropriately selected in consideration of the chain transfer constant of the solvent in accordance with the degree of polymerization of the target copolymer. For example, when the solvent is methanol, S (solvent) / M ( Monomer) = 0.01 to 10 (weight ratio), preferably 0.05 to 3 (weight ratio).

For the copolymerization, a polymerization catalyst is used. Examples of the polymerization catalyst include known radical polymerization catalysts such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, lauryl peroxide, azobisdimethylvaleronitrile, azo Examples include low-temperature active radical polymerization catalysts such as bismethoxydimethylvaleronitrile, and the amount of polymerization catalyst used varies depending on the type of catalyst and cannot be determined unconditionally, but is arbitrarily selected according to the polymerization rate. For example, when azoisobutyronitrile or acetyl peroxide is used, 0.01 to 0.2 mol% is preferable with respect to the vinyl ester monomer, and 0.02 to 0.15 mol% is particularly preferable.
Moreover, the reaction temperature of a copolymerization reaction is performed at about 30 degreeC-a boiling point by the solvent and pressure to be used, More specifically, it is 35-150 degreeC, Preferably it is carried out in 40-75 degreeC.

  In the present invention, the copolymerization ratio of the compound represented by the general formula (2) is not particularly limited, but the copolymerization ratio may be determined in accordance with the introduction amount of the carboxyl group-containing alkyl group described later.

  The obtained copolymer is then saponified. In such saponification, the copolymer obtained above is dissolved in an alcohol or a hydrous alcohol, and the reaction is carried out using an alkali catalyst or an acid catalyst. . Examples of the alcohol include methanol, ethanol, propanol, tert-butanol and the like, and methanol is particularly preferably used. The concentration of the copolymer in the alcohol is appropriately selected depending on the viscosity of the system, but is usually selected from the range of 10 to 60% by weight. Catalysts used for saponification include alkali catalysts such as alkali metal hydroxides and alcoholates such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, lithium methylate, etc., sulfuric acid, Examples include acid catalysts such as hydrochloric acid, nitric acid, metasulfonic acid, zeolite, and cation exchange resin.

The amount of the saponification catalyst used is appropriately selected depending on the saponification method, the target degree of saponification, and the like. When an alkali catalyst is used, the vinyl ester monomer and the general formula (2) are usually used. A ratio of 0.1 to 30 mmol, preferably 2 to 15 mmol, is suitable for 1 mol of the total amount of the compounds shown.
The reaction temperature for the saponification reaction is not particularly limited, but is preferably 10 to 60 ° C (particularly 20 to 50 ° C).

  The content of the carboxyl group-containing alkyl group present in the side chain of the PVA resin thus obtained is not particularly limited, but is 0.1 to 20 mol% (more preferably 0.5 to 15 mol%, particularly 1 to 10). Mol%). When the content of the carboxyl group-containing alkyl group is less than 0.1 mol%, no effect is observed in terms of viscosity stability of the aqueous solution and high-speed coating property, and the reactivity with the crosslinking agent is low. If the effect of the invention is not sufficiently obtained, on the contrary, if it exceeds 20 mol%, the polymerization rate at the time of copolymerization is lowered, or the degree of polymerization of the obtained PVA resin is lowered. When used as a paper surface sizing agent, a sufficient surface paper strength strength cannot be obtained, and when used as a film or coating agent, the strength and water resistance may be insufficient.

  The average degree of polymerization (measured in accordance with JIS K6726) of the PVA-based resin of the present invention is appropriately selected depending on the purpose of use and is not particularly limited, but is usually 300 to 4000 (more preferably 300 to 2600, particularly 500 to 2200). It is preferable that the average degree of polymerization is less than 300, since the strength when formed into a film is lowered. In addition, when a sufficient amount of a carboxyl group-containing alkyl group is introduced into the PVA resin to obtain the effects of the present invention, it is difficult to obtain PVA having an average degree of polymerization exceeding 4000.

  The degree of saponification of the PVA-based resin is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 50 mol% or more (more preferably 70 mol% or more, particularly 80 mol% or more). Preferably, when the saponification degree is less than 50 mol%, the water solubility becomes low, which is not preferable.

The PVA resin having a carboxyl group-containing alkyl group in the side chain thus obtained has characteristics as a polymer electrolyte due to the carboxyl group, and the carboxyl group is bonded to the main chain through the alkyl group, Since the formation of the inner lactone ring hardly occurs, the same or higher effect can be obtained with a modified amount smaller than that of the carboxyl group-modified PVA described in Non-Patent Document 1.
That is, such a PVA resin has a higher dissolution rate in water and an excellent viscosity stability of an aqueous solution as compared with a normal unmodified PVA resin, and the chelating ability of metal ions by carboxyl groups, It also has excellent reactivity with crosslinking agents. Further, such an aqueous solution of PVA-based resin has good coating properties without causing abnormal flow even under high shear during high-speed coating. Moreover, it is excellent in the solubility to water when it is set as a molded object, especially a film. Furthermore, since the aqueous solution of this PVA-type resin is gelatinized by acidifying pH, hydrogel can be obtained easily.

A paper processing agent (surface sizing agent) is mentioned as an application using the chelate-forming ability of the PVA resin with metal ions. This is because when a coating solution containing such a PVA resin is applied to the paper surface, it reacts with the sulfuric acid band in the paper, yields efficiently on the paper surface, and exhibits high barrier performance with a small amount of use. It is.
Similarly, such PVA-based resins exhibit good adhesion to various metal surfaces, and examples of utilization of the characteristics include scaling inhibitors. For example, by applying and drying an aqueous solution of PVA resin on the can wall of a vinyl chloride polymerization can and forming a film, it is possible to prevent scale from adhering to the inner wall of the can during vinyl chloride polymerization. It will be. In addition to such scale inhibitors, it is also effective to use nitrogen-containing polymer compounds such as polyethyleneimine, polyvinylpyrrolidone, polyvinylamine, and amine-modified PVA resins, antioxidants such as polyphenols, and quinone compounds. Is.

Moreover, hydrogel excellent in adhesiveness, water retention, and low temperature flexibility can be obtained by repeating freezing-thawing of such an aqueous PVA resin solution or making the pH of the aqueous solution acidic. At that time, it is also possible to obtain a hydrogel in which metal ions are combined by coexisting various metal salts in an aqueous solution. Such hydrogel is used for biological research, biological treatment, biodiagnosis, etc. It is useful as a hydrogel for use in ionic conductive pressure-sensitive adhesives for bioelectrodes, percutaneous absorption membranes, hydrous patches for cooling therapy, and the like.
Such metal salts include calcium nitrate, magnesium nitrate, calcium chloride, strontium chloride, palladium chloride, beryllium chloride, magnesium chloride rather than monovalent metal salts such as potassium chloride, silver chloride, cesium chloride, sodium chloride and lithium chloride. , Manganese chloride, nickel chloride and the like.

Moreover, the separation / recovery agent of an organic compound is mentioned as a use which utilizes the gelatinization effect | action (it gelatinizes by acidity and degelates by alkalinity) by pH change of this PVA-type resin. This is because an organic compound dissolved or dispersed in water is mixed with an aqueous solution of the PVA resin, and the pH of the system is acidified to make the PVA resin a hydrogel, and the organic compound is taken into the hydrogel. Thus, by separating the produced organic compound-containing hydrogel from the aqueous liquid by a method such as filtration, it is possible to remove and recover the organic compound.
Examples of organic substances targeted by such organic compound removers include organic halogen compounds such as dioxin, trichloroethylene, dichloroethane, dichloromethane, tribromoethylene, dibromoethane, dibromomethane, dioxin, benzene, chlorobenzene, toluene, xylene, parachlorophenol, etc. And aromatic compounds.

  Moreover, as an example using the high reactivity which a carboxyl group has, the water-resistant film or film by combined use of various organic type and inorganic type crosslinking agents is mentioned. Such organic crosslinking agents include aldehyde compounds (formaldehyde, glyoxal, glutardialdehyde, etc.), amino resins (urea resins, guanamine resins, melamine resins, methylol melamine, etc.), epoxy compounds (water-soluble epoxy resins, polyamide polyamines). Epichlorohydrin, etc.), amine compounds (ethylenediamine, hexamethylenediamine, metaxylylenediamine, 1,3-bisaminocyclohexane, polyoxyalkylene type diamine or polyamine, etc.), hydrazine compounds, hydrazide compounds (adipic acid dihydrazide, carbodihydrazide, Polyhydrazide, etc.), acid anhydrides, polyisocyanates, blocked isocyanates and the like. Examples of inorganic crosslinking agents include boric acid, borates (borax, etc.), zirconium compounds (chlorohydroxyoxozirconium ("Zircosol ZC-2" manufactured by Daiichi Rare Element Chemicals), zirconyl nitrate (first rare element) Chemical “Zircozole ZN”)), titanium compounds (tetraalkoxy titanate, etc.), aluminum compounds (aluminum sulfate, aluminum chloride, aluminum nitrate, etc.), phosphorus compounds (phosphite, bisphenol A modified polyphosphoric acid, etc.), alkoxy groups And silicone compounds having a reactive functional group such as glycidyl group, etc., and these crosslinking agents may be used alone or in combination of two or more. Among these, epoxy compounds such as water-soluble epoxy resins and polyamide polyamine epichlorohydrin are effective, and are suitable as a crosslinking agent when the PVA resin of the present invention is used as a protective layer resin for a thermal recording medium.

  The PVA-based resin of the present invention is useful as a raw material for water-soluble packaging materials for various articles such as agricultural chemicals, detergents, laundry clothes, civil engineering additives, bactericides, dyes, and pigments. The saponification degree of the PVA resin when used for such water-soluble packaging is preferably 65 to 98 mol%. In particular, when an acidic substance or an alkaline substance is packaged, the saponification degree is preferably 98.1 to 100 mol%, more preferably 99 to 100 mol%, and this saponification degree is 98.1. If the content is less than mol%, the water solubility of the film may decrease over time when an acidic substance or an alkaline substance is packaged and stored.

Furthermore, the PVA-based resin of the present invention can be used for various applications by utilizing its characteristics. Some of the applications have been described above, but other specific examples include the following.
(1) Adhesive-related adhesives such as wood, paper, aluminum foil, plastics, adhesives, rehumidifiers, binders for non-woven fabrics, binders for various building materials such as gypsum boards and fiber boards, various binders for granulating powder, Additives for cement and mortar, hot melt adhesive, pressure sensitive adhesive, anionic paint fixing agent, etc.

(2) Molded fibers, films, sheets, pipes, tubes, leak-proof membranes, temporary coatings, chemical laces, water-soluble fibers, etc.

(3) Coating-related paper clear coating agent, paper pigment coating agent, paper sizing agent, thermal paper overcoat agent, textile product sizing agent, warp glue, fiber processing agent, leather finishing agent, paint, Antifogging agent, metal corrosion inhibitor, galvanizing brightener, antistatic agent, conductive agent, ship bottom paint, anti-scaling agent, silica binder for inkjet paper, etc.

(4) Emulsifiers After ethylenically unsaturated compounds such as vinyl acetate, butadiene compounds, emulsifiers for emulsion polymerization of various acrylic monomers, hydrophobic resins such as polyolefins and polyester resins, epoxy resins, paraffin, bitumen, etc. Emulsifiers, etc.

(5) Suspension-related dispersion stability for various types of vinyl compounds such as paint dispersion stabilizers such as paints, ink, water color, adhesives, vinyl chloride, vinylidene chloride, styrene, (meth) acrylate, vinyl acetate Agents, etc.

(6) Hydrophobic resin blending agent-related hydrophobic resin antistatic agent, hydrophilicity-imparting agent, composite fiber, film and other additives for molded articles, and the like.

(7) Coagulant-related suspension in water and coagulant of dissolved material, pulp, slurry drainage, etc.

(8) Thickener-related thickeners and gelling agents for various aqueous solutions and emulsions.
(9) Soil improver-related (10) Photosensitizer, electrosensitive relationship, photosensitive resist resin, etc.
(11) Other ion exchange resins, ion exchange membrane relations, chelate exchange resins, etc. Among the above, its usefulness is particularly expected for the uses (1) to (9).

  Hereinafter, the present invention will be specifically described with reference to examples. In the examples, “parts” and “%” mean weight basis unless otherwise specified.

Example 1
In a reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer, 1200 g of vinyl acetate, 60 g of methanol, undecylenic acid (R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ are hydrogen, R ³ is hydrogen, n = 8) Charge 102.6 g (4 mol%), add 0.04 mol% (compared to vinyl acetate monomer) of azobisisobutyronitrile, raise the temperature in a nitrogen stream while stirring, and polymerize Went. Two hours after the start of the polymerization, 0.04 mol% of azobisisobutyronitrile (vs. the initial charged vinyl acetate monomer) was further added to continue the polymerization. Thereafter, when the polymerization rate of vinyl acetate reached 75.2%, the polymerization with the polymerization inhibitor was completed. Subsequently, unreacted vinyl acetate monomer was removed out of the system by a method of blowing methanol vapor to obtain a methanol solution of the copolymer.

  Next, the solution was diluted with methanol to a concentration of 30% and charged into a kneader. While maintaining the solution temperature at 40 ° C., a 2% methanol solution of sodium hydroxide was added to 1 mol unit of vinyl acetate in the copolymer. On the other hand, saponification was carried out by adding an amount of 8 mmol. Saponification progressed as saponification progressed, and finally became particulate. The produced PVA was filtered off, washed well with methanol and dried in a hot air dryer to obtain the desired product.

  The saponification degree of the obtained PVA-based resin (I) was 99.2 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate unit, and the polymerization degree was JIS K 6726. According to a similar analysis, it was 860. The viscosity of a 4% aqueous solution of the PVA-based resin (I) was 8.94 mPa · s (20 ° C.) as measured with a Heppler viscometer, and the amount of modification was calculated as 3.8 moles from NMR measurement. %Met.

Assignment of IR spectrum and ¹ H-NMR (internal standard substance: tetramethylsilane, solvent: DMSO-d6) spectrum of the obtained PVA resin (I) was as follows. The IR chart is shown in FIG. 1, and the NMR chart is shown in FIG.

[IR] (see FIG. 1)
3330 cm ⁻¹ : OH (strong)
2940, 2910 cm ⁻¹ : methylene (strong)
1650cm ^-1: -COOH (medium broad)
1560 cm ⁻¹ : —COO—Na + (medium)
1430 cm ⁻¹ : methylene (strong)
1240 cm ⁻¹ : methine (weak)
1100 cm ⁻¹ : C—O (medium)
850 cm ⁻¹ : methylene (medium)
670 cm < ^-1 >: OH (medium mu)

[ ¹ H-NMR] (see FIG. 2)
1.21-1.23 ppm: Methylene proton (due to modified species)
1.35 to 1.58 ppm: methylene proton 1.86 to 1.92 ppm: methylene proton (due to modified species)
3.81 to 3.85 ppm: methine proton 4.13 to 4.78 ppm: hydroxyl group

The following evaluation was performed about obtained PVA-type resin (I). The results are shown in Tables 1-3.
[Viscosity stability of aqueous solution]
An 8% aqueous solution of PVA-based resin was placed in a glass container, and the temperature of the aqueous solution was 20 ° C. Next, the glass container was left in a constant temperature water bath at 5 ° C., the viscosity after being left for 1 hour and 24 hours was measured, the thickening ratio was determined and evaluated as follows.
○: Thickening ratio is less than 2.5 times ×: Thickening ratio is 2.5 times or more. The thickening ratio is calculated from the following formula.
Thickening factor = (viscosity after standing for 24 hours at 5 ° C) / (viscosity after standing for 1 hour at 5 ° C)

[High speed coatability]
The increase in viscosity of a 10% aqueous solution of PVA resin under a high shear rate at 30 ° C. was measured and evaluated as follows. As a measuring device, a flow tester CFT-500C manufactured by Shimadzu Corporation was used.
○: When the shear rate is 6 × 10 ⁶ / s or more and the viscosity increase shows a maximum value ×… When the shear rate is less than 6 × 10 ⁶ / s and the viscosity increase shows a maximum value

[Water solubility of film]
A cast film having a thickness of 30 μm was prepared by casting a 10% aqueous solution of a PVA resin on a hot roll at 60 ° C. The film was cut into 40 mm × 40 mm, sandwiched between slide mounts, immersed in water stirred at 20 ° C., the time (seconds) until the film was completely dissolved was measured and evaluated according to the following criteria.
○: Less than 40 seconds Δ: 40 to 70 seconds ×: 70 seconds or more

[Alkali resistance of film]
Sodium carbonate is actually wrapped in a 100 mm x 100 mm bag made by heat-sealing the above film and left for 6 months at 40 ° C x 80% RH, and then a 40 mm x 40 mm film piece is collected from the bag. It was immersed in water stirred at 20 ° C., and the time (seconds) was measured until the film was completely dissolved, and evaluated according to the following criteria.
○: Complete dissolution time after actual packaging of sodium carbonate / complete dissolution time before actual packaging is less than 1.3 Δ: Complete dissolution time after actual packaging of sodium carbonate / complete dissolution time before actual packaging is 1.3 or more and less than 1.5 × : Complete dissolution time after actual packaging of sodium carbonate / Complete dissolution time before actual packaging is 1.5 or more

[Separation and recovery of organic compounds]
To 100 g of a 4% aqueous solution of PVA resin, 20 g of trichlorethylene (ETC) was added and shaken, and then the pH of the aqueous solution was adjusted to 4.0 or lower using 1N hydrochloric acid. Thereafter, the produced hydrogel was filtered off with a filter paper, the filtrate was allowed to stand at 60 ° C. for 1 hr, and then the separated water / ETC layer was collected and evaluated according to the following criteria.
○: ETC amount in the filtrate is less than 5 g Δ: ETC amount in the filtrate is 5 g or more and less than 10 g ×: ETC amount in the filtrate is 10 g or more

[Scaling prevention]
A 4% aqueous solution of PVA-based resin was spray-coated on the inner surface of a 1 L reflux condenser and a jacketed stainless steel polymerization tank and dried.
In this polymerization tank, 0.14 g of PVA (degree of saponification 80 mol%, degree of polymerization 2400), 0.08 g of di-2-ethylhexyl peroxydicarbonate, 400 g of deionized water, and 200 g of vinyl chloride monomer were charged and stirred. The temperature was raised to 57 ° C. by passing hot water through the jacket, and polymerization was started. When the pressure in the polymerization tank, which was about 7.0 kg / cm ² G at the start of polymerization, dropped to 6.0 kg / cm ² G, unreacted monomer was recovered, and the polymer slurry was taken out of the system. The post-polymerization scale attached to the polymerization tank wall was peeled off with a scrubber, the amount of scale attached was measured, and evaluated according to the following criteria.
○: Scale adhesion amount less than 10 mg Δ: Scale adhesion amount 10 mg or more, less than 50 mg ×: Scale adhesion amount 50 mg or more

[Applicability to paper surface sizing agent]
4% aqueous solution of PVA-test size press apparatus so that the resin solids 1.0 g / ^{m 2} on acid paper weighing 60 g / ^{m 2} (Kumagai Riki Kogyo Co., Speed: 90m / min, (Linear pressure: 11 kg / cm), dried with a cylindrical rotary dryer at 105 ° C for 2 minutes, and then double-sided with a super calender (temperature: 80 ° C, linear pressure: 40 kg / cm) for coating I got paper.
The obtained coated paper was evaluated for the sizing degree, air permeability, oil absorption, and surface strength in the following manner.

Steecht sizing degree: Measured according to JIS P-8122.
Air permeability: Based on JIS P-8117, a test piece was fixed to an Oken type air permeability tester (manufactured by Asahi Seiko Co., Ltd.), and the time (seconds) through which 100 mL of air passed was measured.
Oil absorption: In accordance with JIS P-8130, an oil oil absorption tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) was used to measure the time (seconds) that oil was absorbed from the paper surface to the inside.
Surface paper strength: IGT pick strength (cm / sec) is measured using FINE INK TV-20 (manufactured by Dainippon Ink & Chemicals, Inc.) as an ink using an IGT printing tester (manufactured by Kumagaya Riken Kogyo Co., Ltd.). went.

[For heat sensitive applications]
A thermal recording medium was prepared and evaluated in the following manner.
Preparation of solution B: 10 parts of 3-dimethylamino-6-methyl-7-phenylaminofluorane, 25 parts of 1,3-di (2-methylphenoxy) ethane, 5 parts of a 5% aqueous solution of methylcellulose and 50 parts of water were mixed. Then, it was pulverized with a sand mill until the average particle size became 3 μm.
Preparation of the filtrate: 10 parts of 4-hydroxy-4-isopropoxydiphenyl sulfone, 5 parts of a 5% aqueous solution of methylcellulose, and 25 parts of water were mixed and pulverized with a sand mill until the average particle size became 3 μm.
Preparation of recording layer: 90 parts of solution A, 40 parts of solution B, 50 parts of 20% aqueous solution of oxidized starch and 10 parts of water were mixed and stirred, and then applied and dried so that the coating amount after drying was 6 g / m ^2. A heat-sensitive recording layer was obtained.
Preparation of protective layer: On the obtained heat-sensitive recording layer, 200 parts of a 10% aqueous solution of PVA resin, 70 parts of kaolin, 30 parts of a 30% aqueous solution of zinc stearate, 20 parts of a 5% aqueous solution of polyamide epichlorohydrin, 100 parts of water The coating liquid obtained by mixing and stirring was applied and dried by a roll blade coating method so that the coating amount after drying was 4 g / m ² and subjected to a calendar treatment to obtain a thermosensitive recording medium having a protective layer.

Recording density: The density of a recorded image obtained with a thermal simulator (manufactured by Okura Electric Co., Ltd., TH-PMID) was measured with a Macbeth densitometer (Macbeth Co., Ltd., model RD-100).
Solvent resistance: Drop a drop of ethanol on the recording surface and visually observe the fogging.
◎: No problem in practical use. ○: Almost no problem in practical use. △: Some problem in practical use. X: There is a problem in practical use. Plasticizer resistance: The heat-sensitive recording material after recording is tripled with a vinyl chloride film containing a plasticizer. The discoloration after wrapping and standing at 40 ° C. for 72 hours was visually observed.
◎: No problem in practical use ○: Almost no problem in practical use △: Some problem in practical use ×: Practical problem in printability: Applicability of off-line ink (tack value 10) 0.4 cc RI type tester manufactured by Meisei Co., Ltd. Print on the protective layer of the thermal recording medium and visually observe the ink setting.
◎: No problem in practical use ○: Almost no problem in practical use △: Some problem in practical use ×: Problem in practical use

Example 2
In a reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer, vinyl acetate 1600 g, methanol 320 g, undecylenic acid (R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ are hydrogen, R ³ is hydrogen, n = 8) Charge 68.4 g (2 mol%), add 0.04 mol% (azo vinyl monomer) to the azobisisobutyronitrile, raise the temperature in a nitrogen stream while stirring, and polymerize Went. Two hours after the start of the polymerization, 0.04 mol% of azobisisobutyronitrile (vs. the initial charged vinyl acetate monomer) was further added to continue the polymerization. Thereafter, when the polymerization rate of vinyl acetate reached 73.1%, the polymerization with the polymerization inhibitor was completed. Subsequently, unreacted vinyl acetate monomer was removed out of the system by a method of blowing methanol vapor to obtain a methanol solution of the copolymer.

  Next, the solution was diluted with methanol and adjusted to a concentration of 30% and charged into a kneader. While maintaining the solution temperature at 40 ° C., a 2% methanol solution of sodium hydroxide was added to 1 mol unit of vinyl acetate in the copolymer. On the other hand, saponification was carried out by adding an amount of 8 mmol. Saponification progressed as saponification progressed, and finally became particulate. The produced PVA-based resin was separated by filtration, washed well with methanol, and dried in a hot air dryer to obtain the desired product.

The saponification degree of the obtained PVA-based resin (II) was 99.6 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate unit, and the polymerization degree was JIS K 6726. As a result of analysis, it was 1300. The viscosity of a 4% aqueous solution of the PVA-based resin (II) was 12.4 mPa · s (20 ° C.) as measured with a Heppler viscometer, and the amount of modification was calculated as ¹ H-NMR measurement. It was 1 mol%.

  Evaluation similar to Example 1 was performed about obtained PVA-type resin (II). The results are shown in Tables 1-3.

Example 3
To a reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer, 1600 g of vinyl acetate, 320 g of methanol, bephenyl undecylenate (R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ are hydrogen, R ³ is a bephenyl group ( -C ₂₂ H ₄₅ ), n = 8) 45.8 g (0.5 mol%) was added, azobisisobutyronitrile was added in an amount of 0.06 mol% (compared with the vinyl acetate monomer) and stirred. The polymerization was carried out by raising the temperature under a nitrogen stream.
When the polymerization rate of vinyl acetate reached 81.2%, the polymerization was terminated, and then the unreacted vinyl acetate monomer was removed out of the system by blowing methanol vapor. Got.

Next, the solution was diluted with methanol and adjusted to a concentration of 30% and charged into a kneader. While maintaining the solution temperature at 40 ° C., a 2% methanol solution of sodium hydroxide was added to 1 mol unit of vinyl acetate in the copolymer. On the other hand, saponification was carried out by adding an amount of 9 mmol. Saponification progressed as saponification progressed, and finally became particulate.
The produced PVA-based resin was separated by filtration, washed well with methanol, and dried in a hot air dryer to obtain the desired product.

The saponification degree of the obtained PVA-based resin (III) was 99.4 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate unit, and the polymerization degree was JIS K 6726. It was 2100 when analyzed according to the same. Further, the viscosity of a 4% aqueous solution of the PVA resin was 46.5 mPa · s (20 ° C.) as measured with a Heppler viscometer, and the amount of modification was 0.3 mol as calculated from ¹ H-NMR measurement. %Met.

  Assignment of IR spectrum and 1H-NMR (internal standard substance; tetramethylsilane, solvent: DMSO-d6) spectrum of the obtained PVA resin (III) was as follows.

[IR] (see FIG. 3)
3330 cm ⁻¹ : OH (strong)
2940, 2910 cm ⁻¹ : methylene (strong)
1720 cm ⁻¹ : —COO-R
1650 cm ⁻¹ : —COOH (medium broadcast)
^{1560cm -1: -COO-Na + (} medium)
1430 cm ⁻¹ : methylene (strong)
1240 cm ⁻¹ : methine (weak)
1100 cm ⁻¹ : C—O (medium)
850 cm ⁻¹ : methylene (medium)
670 cm < ^-1 >: OH (medium mu)

[ ¹ H-NMR] (see FIG. 4)
1.21-1.23 ppm: Methylene proton (due to modified species)
1.35 to 1.58 ppm: methylene proton 1.86 to 1.92 ppm: methylene proton (due to modified species)
3.81 to 3.85 ppm: methine proton 4.13 to 4.78 ppm: hydroxyl group

  Evaluation similar to Example 1 was performed about obtained PVA-type resin (III). The results are shown in Tables 1-3.

Example 4
In a reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer, 1800 g of vinyl acetate, 1260 g of methanol, methyl undecylenate (R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ are hydrogen, R ³ is a methyl group) , N = 8) 8.28 g (0.2 mol%) was charged, 0.06 mol% of azobisisobutyronitrile (with respect to the charged vinyl acetate monomer) was added, and the temperature was maintained under a nitrogen stream while stirring. Was raised to carry out polymerization.
When the polymerization rate of vinyl acetate reaches 80.1%, the polymerization is terminated. Subsequently, unreacted vinyl acetate monomer is removed from the system by blowing methanol vapor, and a methanol solution of copolymer is obtained. Got.

Next, the solution was diluted with methanol and adjusted to a concentration of 30% and charged into a kneader. While maintaining the solution temperature at 40 ° C., a 2% methanol solution of sodium hydroxide was added to 1 mol unit of vinyl acetate in the copolymer. On the other hand, saponification was carried out by adding an amount of 9 mmol. Saponification progressed as saponification progressed, and finally became particulate.
The produced PVA resin (IV) was filtered off, washed thoroughly with methanol and dried in a hot air dryer to obtain the desired product.

  The saponification degree of the obtained PVA-based resin (IV) was 99.4 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate unit, and the polymerization degree was JIS K 6726. According to the same analysis, it was 1000. The viscosity of a 4% aqueous solution of the PVA resin was 11.0 mPa · s (20 ° C.) as measured with a Heppler viscometer, and the amount of modification was 0.21 mol% as calculated from NMR measurement. It was.

Assignment of IR spectrum and ¹ H-NMR (internal standard substance: tetramethylsilane, solvent: DMSO-d6) spectrum of the obtained PVA-based resin (IV) was as follows.

[IR] A spectrum similar to that of FIG. 3 in Example 3 was obtained.
[ ¹ H-NMR] A spectrum similar to that of FIG.
Evaluation similar to Example 1 was performed about obtained PVA-type resin (IV). The results are shown in Tables 1-3.

Comparative Example 1
In Example 1, undecylenic acid was not charged, but only vinyl acetate was polymerized (S / M = 0.5, S: methanol, M: vinyl acetate), and saponification was performed in the same manner. (V) was obtained.
The saponification degree of the obtained PVA-based resin (V) was 99.5 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate unit, and the polymerization degree was JIS K 6726. It was 1100 when analyzed according to the same. The viscosity of a 4% aqueous solution of the PVA resin (V) was 13.1 mPa · s (20 ° C.) as measured with a Heppler viscometer.
Evaluation similar to Example 1 was performed about the obtained PVA-type resin (V). The results are shown in Tables 1-3.

Comparative Example 2
In Example 1, monomethyl maleate (2 mol%) was added in place of undecylenic acid, polymerization (S / M = 0.5, S: methanol, M: vinyl acetate) was performed, and saponification was performed in the same manner. And PVA-based resin (VI) was obtained.
The obtained PVA-based resin (VI) had a saponification degree of 99.2 mol% and a polymerization degree of 1100. The viscosity of a 4% aqueous solution of the PVA resin (VI) was 13.0 mPa · s (20 ° C.) as measured with a Heppler viscometer.
Evaluation similar to Example 1 was performed about obtained PVA-type resin (VI). The results are shown in Tables 1-3.

  The PVA-based resin of the present invention is excellent in viscosity stability of aqueous solution and high-speed coating property, and has excellent chelating ability of metal ions and reactivity with various crosslinking agents. It is effective for applications such as water-soluble films for packaging various articles, separation and recovery agents for various organic compounds, adhesives, emulsifiers, suspension materials, fiber processing agents, and the like.

It is IR spectrum chart of PVA-type resin (I). Is a ¹ H-NMR spectrum chart of PVA-based resin (I). It is IR spectrum chart of PVA-type resin (III). Is a ¹ H-NMR spectrum chart of PVA-based resin (III).

Claims (14)

A polyvinyl alcohol-based resin comprising a structural unit having a carboxyl group-containing alkyl group in the side chain represented by the general formula (1).

(Wherein, ^{R 3} is shows the hydrogen atom, an alkyl group or an alkali metal) Polyvinyl alcohol of claim 1 Symbol mounting, characterized by comprising saponifying a copolymer of an unsaturated monomer having a carboxyl group containing alkyl group represented by a vinyl ester-based monomer and the general formula (2) Resin.

(Wherein, ^{R 3} is shows the hydrogen atom, an alkyl group or an alkali metal) The polyvinyl alcohol resin according to claim 1 or 2, wherein the content of the structural unit having a carboxyl group-containing alkyl group in the side chain represented by the general formula (1) is 0.1 to 20 mol%. Paper coating agent, which comprises using the claim 1-3 polyvinyl alcohol-based resin according to any one. An adhesive using the polyvinyl alcohol resin according to any one of claims 1 to 3 . Claim 1-3 hydrogel which comprises using a polyvinyl alcohol-based resin according to any one. The organic compound remover characterized by using the polyvinyl alcohol-type resin in any one of Claims 1-3 . A molded article using the polyvinyl alcohol-based resin according to any one of claims 1 to 3 . The molded article according to claim 8, which is a water-soluble film for packaging an article selected from agricultural chemicals, detergents, laundry clothes, civil engineering additives, bactericides, dyes and pigments. The molded article according to claim 8 or 9, wherein a polyvinyl alcohol resin having a saponification degree of 90 mol% or more is used. The coating agent characterized by using the polyvinyl alcohol-type resin in any one of Claims 1-3 . The scaling inhibitor characterized by using the polyvinyl alcohol-type resin in any one of Claims 1-3 . The polyvinyl alcohol-type resin in any one of Claims 1-3 is used, The emulsifier characterized by the above-mentioned. Suspending agents, which comprises using the claim 1-3 polyvinyl alcohol-based resin according to any one.

Images