JP2000063427A - Preparation of poly(vinyl alcohol) type resin containing acetoacetic ester group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin excellent in transparency regardless of the degree of saponification of the raw materials, by reacting a poly(vinyl alcohol) type resin with a diketene in the coexistence of a fatty acid ester. SOLUTION: A preferable amt. of a fatty acid ester for coexistence is 50-100 pts.wt. based on 100 pts.wt. of a poly(vinyl alcohol) type resin (PVA). Further, an acid anhydride is put together. A preferable amt. of the coexistent acid anhydride is 1-500 pts.wt. based on 100 pts.wt. of the PVA. A preferable PVA as a raw material is a PVA obtd. by saponifying a poly(vinyl acetate) using a saponification catalyst such as an alkaline compd. in a lower alcohol soln., its deriv., a saponified product obtd. from a copolymer of vinyl acetate and a monomer copolymerizable with vinyl acetate, or the like. A basic compd. such as sodium acetate, potassium acetate, or a prim., sec. or tert. amine is effective as a catalyst for the reaction. A preferable catalyst amt. is about 0.1-3.0 wt.% based on the PVA.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyvinyl alcohol resin containing an acetoacetic acid ester group (hereinafter referred to as AA-P
(Hereinafter abbreviated as VA), and more specifically, to a method for producing AA-PVA that can suppress the formation of insoluble matter and coarse particles and that can easily separate the target substance.

[0002]

2. Description of the Related Art Conventionally, as a method for producing AA-PVA, a method of reacting a polyvinyl alcohol resin (hereinafter abbreviated as PVA) with diketene has been carried out. A method of reacting diketene, a method of reacting liquid diketene and diketene by adding an inert PVA non-solvent (JP-A-55-94904), and a method of reacting PVA and diketene gas (JP-A-55-137107). JP-A-57-40508) has been proposed.

[0003]

However, in the above-mentioned method, when the ordinary PVA is used, good A
Although the AA-PVA can be obtained, the obtained AA-PVA may be colored or an insoluble matter may be generated due to the non-uniform reactivity of diketene. Since a substance may be produced, meticulous process control is required. Even in the method, insoluble matter may be produced in the case of PVA having a saponification degree of 85 mol% or less. AA-PVA that has excellent transparency regardless of the degree of saponification and that can suppress the formation of insolubles
Is desired, and further, in order to respond to the recent simplification of the production process, a production method in which the target product can be easily separated after the reaction is desired.

[0004]

Therefore, as a result of diligent studies in view of the present situation, the present inventor has found that when PVA and diketene are reacted to produce AA-modified PVA, PVA and diketene are coexisted in the presence of a fatty acid ester. By adopting the production method of reacting, AA-PVA having excellent transparency of the aqueous solution can be obtained regardless of the saponification degree of the raw material PVA, and an appropriate solvent is different depending on the saponification degree (for example, saponification degree). When it is 75 mol% or more, water, when the saponification degree is 68 to 75 mol%, a mixed solvent of water / methanol = 7/3 (weight ratio),
Water / methanol = 1 at a saponification degree of about 40 to 68 mol%.
/ 2 (weight ratio) mixed solvent, saponification degree of 40 mol% or less of methanol) can be suppressed to form insoluble matter, coarse particles and block substances can also be suppressed, and a good-shaped product can be obtained. Further, the present invention has been completed by further discovering that the desired product can be easily separated after the completion of the reaction, and that the effect of the present invention can be remarkably obtained by further coexisting an acid anhydride in the production method. Came to.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

The PVA used as the raw material of the present invention is not particularly limited, but generally PVA obtained by saponifying a lower alcohol solution of polyvinyl acetate with a saponification catalyst such as alkali, or a derivative thereof, Further, a saponified product of a copolymer of vinyl acetate and a monomer having a copolymerizability with vinyl acetate can be used. Examples of the monomer include ethylene, propylene, isobutylene, α-octene and α. -Dodecene, olefins such as α-octadecene, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, unsaturated acids such as itaconic acid or salts thereof or mono- or dialkyl esters, etc., acrylonitrile, methacrylonitrile, etc. Nitriles, amides such as acrylamide and methacrylamide, ethylene sulphate Phosphate, allyl sulfonic acid, an olefin sulfonic acid or its salt such as methallyl sulfonic acid, alkyl vinyl ethers, N- acrylamidomethyl trimethylammonium chloride, allyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride, dimethyl allyl vinyl ketone, N-
Vinylpyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether and other polyoxyalkylene (meth) allyl ethers, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) )
Polyoxyalkylene (meth) acrylate such as acrylate, polyoxyethylene (meth) acrylamide,
Polyoxyalkylene (meth) acrylamide such as polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene Examples thereof include saponified copolymers with allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine and the like.

The degree of saponification of PVA as a raw material of the present invention is 5 to 100 mol% (further 65 to 99.5 mol%).
Is preferred, and the average degree of polymerization is preferably 50 to 6000 (more preferably 100 to 4000).

Further, the shape of the PVA is not particularly limited, but in consideration of uniform adsorption of diketene, homogenization of reaction by absorption, improvement of reaction rate with diketene, etc., powdery, especially narrow particle size distribution. , And those having porosity are preferable, and the particle size thereof is preferably 50 to 450 mesh, more preferably 80 to 320 mesh.

Further, the PVA may contain a few% of alcohols and water in the production process, but these components react with diketene, consume diketene, and lower the reaction rate of diketene. In the case of using for the reaction, it is desirable to reduce the temperature as much as possible by heating or reducing the pressure before use.

In the present invention, the powdered PVA can be used as the raw material PVA as described above. However, considering the simplification of the manufacturing process, the raw material PVA after the saponification step at the time of manufacturing the raw material PVA can be obtained. Solvent (methanol, methanol, (iso)
It is preferable to replace the slurry PVA containing propanol etc.) with a fatty acid ester and use it as the raw material PVA.

The present invention is characterized by reacting the above PVA with diketene in the coexistence of a fatty acid ester. The reaction method will be specifically described.

First, the fatty acid ester used in the method is not particularly limited, and examples thereof include methyl acetate, ethyl acetate, isopropyl acetate, methyl propionate, and the like, and methyl acetate is preferably used.

In the present invention, the fatty acid ester may coexist during the reaction between PVA and diketene as described above. Such a fatty acid ester may be added to PVA in advance and then the diketene may be reacted. Or PV
Fatty acid ester may be supplied at the same time as the reaction of A with diketene, and further, fatty acid ester may be added to diketene in advance and then PVA may be reacted. From the viewpoint of dispersion, it is preferable to add the fatty acid ester to PVA in advance.
This method will be described in more detail, but is not limited to this.

First, the fatty acid ester is contained in PVA. However, the method of containing is not particularly limited, and PVA and the fatty acid ester may be mixed and stirred.
It is also preferable to preliminarily contain about 0.1 to 1.0% by weight of sodium acetate in the powdered state, and when the solvent-containing PVA after saponification is used, PVA100
It is preferable to use a solvent in which the content of the solvent is adjusted to about 50 to 500 parts by weight with respect to parts by weight. The content of fatty acid ester is 50 to 1 with respect to 100 parts by weight of PVA.
000 parts by weight (further 100 to 500 parts by weight) is preferable, and if the content is less than 50 parts by weight, a non-uniform AA reaction occurs, and conversely, if it exceeds 1000 parts by weight, productivity is lowered, which is not preferable.

Next, PV containing fatty acid ester
A is reacted with diketene, and such diketene can be used in the reaction in either a gaseous state or a liquid state, and there is no particular limitation.

As the reaction conditions at this time, when liquid diketene is used, it is preferable to dissolve, adsorb and absorb it uniformly by a means such as spraying under an inert gas (nitrogen gas etc.) atmosphere at a temperature of 20. Warm to ~ 120 ° C and continue stirring or fluidization.

When diketene gas is used, the contact temperature is preferably 30 to 250 ° C. (further 50 to 200 ° C.), and the partial pressure of diketene at a temperature at which gaseous diketene does not liquefy when it contacts PVA. It is preferable to bring them into contact with each other under the conditions, but there is no problem in forming a part of the diketene gas into droplets.

The contact time may be adjusted according to the contact temperature (longer time when temperature is low, shorter time when temperature is high), and is usually selected appropriately from 1 minute to 6 hours.

Further, when supplying diketene gas,
It may be used as a mixture with another inert gas, or may be heated by allowing PVA to absorb the diketene gas, or may be heated while heating the PVA and then contacted with the gas. .

As the catalyst during the reaction, sodium acetate,
Basic compounds such as potassium acetate, primary amine, secondary amine, and tertiary amine are effective, and the amount of the catalyst is PVA.
0.1 to 3.0% by weight (further 0.1 to 1.0
% By weight). Further, since PVA usually contains sodium acetate, it is often unnecessary to add a catalyst, and when the amount of the catalyst is too large, a side reaction of diketene is likely to occur, which is not preferable.

As a reaction device for carrying out the reaction, a device capable of heating and equipped with a stirrer is sufficient.
Examples thereof include a kneader, a Henschel mixer, a ribbon blender, various other blenders, and a stirring / drying device.

Thus, no insoluble matter or coarse particles are produced,
In addition, the AA-PVA which is easy to separate the target product can be obtained. In the present invention, the coexistence of an acid anhydride during the above-mentioned reaction produces an insoluble matter in the aqueous solution of the AA-PVA. Is preferable, and it is preferable in that the transparency is improved. The acid anhydride is preferably a carboxylic acid anhydride, and specific examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, and acetic anhydride is preferably used. As with the above-mentioned fatty acid ester, it is sufficient that such an acid anhydride also exists during the reaction of PVA and diketene,
The coexisting method is not particularly limited, and it is preferable to preliminarily contain PVA in the same manner as the fatty acid ester from the viewpoint of maximizing the effects of the present invention. The content is 1 with respect to 100 parts by weight of PVA. ˜500 parts by weight (further, 10 to 200 parts by weight) is preferable, and if the content is less than 1 part by weight, the effect of addition cannot be obtained. Absent.

In the AA-PVA obtained by the method of the present invention as described above, a fatty acid ester is allowed to coexist during the reaction, so that compared with the conventional method (especially the method of occluding an organic acid),
Target product, especially AA-modified P with low saponification degree (less than 85 mol%)
The VA can be easily isolated / separated, contains almost no insoluble matter or coarse particles, and can be easily separated after production, and can be used in various applications as described below.

Molded products: fibers, films, sheets,
Pipes, tubes, leak-proof films, temporary films, chemical laces, water-soluble fibers, etc./Adhesives: Adhesives for wood, paper, aluminum foil, plastics, adhesives, rewetting agents, non-woven fabric binders, gypsum boards Binders for various building materials such as paper and fiberboard, binders for various powder granulations, additives for cement and mortar, hot-melt adhesives, pressure-sensitive adhesives, adhesives for anionic paints, etc. Clear coating agent, paper pigment coating agent, paper internal sizing agent, fiber product size agent, warp paste agent, fiber processing agent, leather finishing agent, paint, anti-fog agent, metal corrosion inhibitor, zinc plating gloss Agents, antistatic agents, conductive agents, temporary paints, etc. ・ Hydrophobic resin blending agents: Hydrophobic resin antistatic agents, hydrophilicity imparting agents, composite fibers, films and other additives for molded products ・ Suspension dispersion Jozai relationship: paints, India ink, aqueous color, the pigment dispersion stabilizers such as glue, vinyl chloride, vinylidene chloride,
Dispersion stabilizers for suspension polymerization of various vinyl compounds such as styrene, (meth) acrylate, vinyl acetate, etc. ・ Emulsion dispersion stabilizer relationship: Various acrylic monomers, ethylenically unsaturated compounds, emulsifiers for emulsion polymerization of butadiene compounds, polyolefins , Hydrophobic resin such as polyester resin, post-emulsifier such as epoxy resin, paraffin, bitumen, etc. ・ Thickener relations: Thickeners for various aqueous solutions and emulsions ・ Flocculant relations: Flocculants for suspensions in water and dissolved substances, Drainage of pulp, slurry, etc. ・ Exchange resin, etc .: Ion exchange resin, chelate exchange resin, ion exchange membrane, etc. ・ Others: Soil conditioner, photosensitizer, photosensitive resist resin, etc.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples. Unless otherwise specified, "%",
The term "part" indicates a weight basis.

Example 1 First, 100 parts of PVA powder containing 0.5% of sodium acetate (saponification degree: 80 mol%, polymerization degree: 2,100, particle size: 7 mesh or less) was preliminarily charged with 200 parts of methyl acetate and 50 parts of acetic anhydride. It was added to make a slurry. Next, pour slurry PVA into a kneader and stir it at 60 ° C.
After the temperature was raised to 60 ° C., the mixture was further stirred at 60 ° C. for 1 hour, and then 6.5 parts of diketene was added over 30 minutes to obtain a further 60
The reaction was carried out at 30 ° C. for 30 minutes to obtain AA-PVA containing 3.0 mol% of acetoacetic acid group.

The obtained AA-PVA was sufficiently washed with methanol to remove the solvent and then dried at 50 ° C. for 18 hours to obtain dried AA-PVA, which was evaluated in the following manner. (Insolubles) 200 ml of deionized water in Erlenmeyer flask
Approximately 20 g (Sg) of the above-mentioned dried AA-PVA was sufficiently dispersed in the mixture, and the mixture was stirred at 80 ° C. for 1 hour. Then, the Erlenmeyer flask was transferred to a water tank at 20 ° C., and the mixture was stirred for 1 hour.
Was dissolved. Then, it is filtered through a wire mesh (Ag) of 44 μm which is weighed in advance. Further, the insoluble content in the Erlenmeyer flask was completely transferred onto a wire net with 2 liters of warm water at 80 to 90 ° C. and washed, and then dried for 2 hours in an electric constant temperature dryer at 105 ° C., and its weight (Bg) was measured. Then, the insoluble content (%) was obtained from the following formula (1).

[0028]

## EQU1 ## [(B−A) / S] × 100 (1) (Transparency) Dry AA-PVA is dried for 2 hours in an electric constant temperature dryer at 105 ° C., and 4 g of the AA-PVA is then dried. Was collected and sufficiently dispersed in 96 g of ion-exchanged water in an Erlenmeyer flask, and then stirred at 80 ° C. for 1 hour), and then 20
The Erlenmeyer flask was transferred to a water tank at ℃ and stirred for 1 hour to dissolve the AA-PVA. The solution of the obtained AA-PVA is 2
The light transmittance (%) at 430 nm was measured at 5 ° C. (Amount of coarse particles) 100 g of dried AA-PVA was put on a standard mesh sieve 2800 μm (7 mesh), placed on an electric horizontal vibrator (200 times / minute, swing width 50 mm), vibrated for 30 minutes, and then on the sieve. The weight (g) of AA-PVA was measured. (Shape) The dried AA-PVA was visually observed and evaluated as follows. ○ −−− No beards or blocks were found. × −−− Beards or blocks were generated.

Example 2 PVA containing a solvent (a mixed solvent of methanol / methyl acetate = 2.5 / 1.0 (weight ratio)) after saponification during PVA production
(Saponification degree 73 mol%, degree of polymerization 800, particle size 7 when dried
Weight over mesh is 0.3%, solvent content is 55%) 1
82 parts were washed and replaced 5 times with a mixed solution of 400 parts of methyl acetate and 40 parts of acetic anhydride, and PVA in a slurry state containing 400 parts of methyl acetate and 40 parts of acetic anhydride to 100 parts of PVA ( Thus, 0.3 part of sodium acetate was added to 100 parts of PVA). Next, the obtained slurry-like PVA was charged in a kneader and stirred with stirring 6
After the temperature was raised to 0 ° C., 4.8 parts of diketene was added over 30 minutes, and the mixture was further reacted at 60 ° C. for 30 minutes to obtain AA-PVA containing 2.5 mol% of acetoacetic acid groups. The AA-PVA thus obtained was evaluated in the same manner as in Example 1.

Example 3 PVA containing a solvent (a mixed solvent of methanol / methyl acetate = 2.2 / 1.0 (weight ratio)) after saponification during PVA production
(Saponification degree 80 mol%, degree of polymerization 2400, weight of dry mesh size 7 mesh or more 0.5%, solvent content 45%)
222 parts were washed and replaced with 400 parts of methyl acetate 5 times to replace 100 parts of PVA with 400 parts of methyl acetate.
To obtain a slurry-state PVA containing 100 parts (containing 0.3 part of sodium acetate based on 100 parts of PVA). Then
The obtained slurry PVA was charged into a reaction can equipped with a stirring blade, heated to 57 ° C. with stirring, 6.5 parts of diketene was added over 30 minutes, and further reacted at 57 ° C. for 30 minutes, AA-PVA containing 2.6 mol% of acetoacetic acid groups was obtained.

Regarding the obtained AA-PVA, Example 1
It evaluated similarly to.

Example 4 Saponification degree 80 mol%, degree of polymerization 2100, particle size 7 when dried
The weight above the mesh is 0.3%), and the addition amount of methyl acetate and acetic anhydride is 70 parts and 5%, respectively.
The acetoacetic acid group was prepared in the same manner as in Example 1 except that 3 parts were used.
An AA-modified PVA containing 0 mol% was obtained and evaluated in the same manner.

Example 5 AA-PVA containing 2.8 mol% of acetoacetic acid groups was obtained in the same manner as in Example 1 except that only 250 parts of methyl acetate was added, and the same evaluation was carried out. .

Comparative Example 1 In Example 1, 200 parts of methyl acetate and 50 parts of acetic anhydride were used.
AA-PVA containing 3.0 mol% of acetoacetate groups, except that 10 parts of acetic acid was added instead of 10 parts.
Was obtained and evaluated in the same manner.

Table 1 shows the evaluation results of the examples and comparative examples.

[0036]

[Table 1] Insoluble matter (%) Transparency (%) Coarse particle amount (g) Product shape Example 1 0.01 97 0.1 ○ 〃 2 0.04 85 0.5 ○ 〃 3 0.02 92 0.8 ○ 〃 4 0.03 90 0.1 ○ 〃 5 0.02 92 0.1 ○ Comparative Example 1 1.2 65 2.5 ×

[0037]

INDUSTRIAL APPLICABILITY In the method for producing AA-PVA of the present invention, PVA and diketene are reacted in the coexistence of a fatty acid ester, so that AA is excellent in transparency regardless of the saponification degree of the raw material PVA. PVA can be obtained, the generation of insoluble matter can be suppressed, and the generation of coarse particles and blocks can be suppressed.
A product having a good shape can be obtained, and the target product can be easily separated after the reaction is completed, which is very useful for various applications as described above.

Continued front page    F-term (reference) 4J100 AA02Q AA03Q AA06Q AA15Q                       AA19Q AC03Q AC04Q AE02Q                       AE18Q AG04P AJ01Q AJ02Q                       AJ08Q AJ09Q AK01Q AK32Q                       AL34Q AL36Q AM02Q AM15Q                       AM21Q AN04Q AN05Q AP01Q                       AQ08Q BA03Q BA08Q BA32Q                       BA56Q BB01Q CA04 CA31                       HA09 HC27 JA01 JA03 JA05                       JA11 JA13 JA16 JA18 JA37                       JA64 JA67

Claims (4)

[Claims] 1. When producing a polyvinyl alcohol resin containing an acetoacetic acid ester group by reacting a polyvinyl alcohol resin and diketene, the polyvinyl alcohol resin and diketene are reacted in the presence of a fatty acid ester. A method for producing a polyvinyl alcohol resin containing an acetic acid ester group. 2. The method for producing a polyvinyl alcohol-based resin containing an acetoacetic acid ester group according to claim 1, wherein the coexisting amount of the fatty acid ester is 50 to 100 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol-based resin. . 3. The method for producing a polyvinyl alcohol-based resin containing an acetoacetic acid ester group according to claim 1 or 2, further comprising coexisting with an acid anhydride. 4. The production of a polyvinyl alcohol resin containing an acetoacetic acid ester group according to claim 3, wherein the coexisting amount of the acid anhydride is 1 to 500 parts by weight based on 100 parts by weight of the polyvinyl alcohol resin. Law.