JP2002241596A - Biodegradable resin aqueous dispersion and biodegradable composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable resin aqueous emulsion which can be used as a coating or the like for fiber products, paper products, and the like to improve the physical properties such as water resistance, oil resistance, and air tightness of the fiber products and the paper products without deteriorating the biodegradability of the fiber products and the paper products, and has stable dispersibility. SOLUTION: This biodegradable resin aqueous dispersion is characterized by dispersing and stabilizing a polyesterpolycarbonate-based biodegradable resin in water. It is preferable that the biodegradable resin aqueous dispersion contains a cationic polymer compound having an average mol.wt. of >=300,000 or an anionic polymer compound having an average mol.wt. of >=300,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable resin aqueous dispersion and a biodegradable composite material.

[0002]

2. Description of the Related Art Products made of animal and plant raw materials, such as vegetable fibers such as cloth products and paper products, and animal materials such as leather, are easily decomposed by microorganisms. It is easily biodegraded even when it is buried in the soil and disposed of, so that it has an advantage that disposal is easy. On the other hand, fabric products and paper products are inferior in physical properties such as water resistance, solvent resistance, and airtightness as compared with synthetic resins, and in recent years, fabric products and paper products have been coated or laminated with synthetic resins such as polyolefins. To improve water resistance, solvent resistance, airtightness and the like.

However, since synthetic resins such as polyolefins are hardly decomposed by microorganisms and the like,
Cloth and paper products coated or laminated with synthetic resin are difficult to dispose of by burying. Also, in the case of disposal by incineration, since the calories burned during incineration are high, problems such as damaging the incinerator and promoting global warming,
There is a possibility that harmful gas is generated to cause environmental pollution. In view of such a problem, it has been proposed to use an aqueous dispersion of a biodegradable resin for covering cloth products and paper products.

For example, JP-A-2-222421 proposes a biodegradable composite material coated with an aqueous dispersion of a polyhydroxybutyric acid / polyhydroxyvaleric acid copolymer. When a large amount of a water-soluble polymer is used for dispersing the biodegradable composite material, there is a problem that the water resistance of the biodegradable composite material becomes insufficient.
JP-A-9-78494 discloses polylactic acid and / or
Alternatively, an aqueous coating composition has been proposed in which particles of a copolymer with another hydroxycarboxylic acid and a filler are dispersed in water using a water-soluble polymer. However, this water-based coating composition is complicated to produce, for example, as an aqueous dispersion by wet micronization such as crystallization, and is used for applications requiring transparency because it contains a filler as an essential component. There was a problem that can not be. Furthermore, since this water-based coating composition uses a large amount of a water-soluble polymer to disperse the biodegradable resin, when a biodegradable composite material is obtained by coating on paper or the like, the obtained biodegradable composite material is obtained. Not only has the problem that the water resistance of the conductive composite material is insufficient,
Some resins have high hydrolyzability, and when kept at a high temperature after being made into an aqueous dispersion, there have been problems such as a decrease in the molecular weight of the resin and a decrease in the strength and water resistance of the coating film.

[0005] The present invention has been made in view of the above points,
Excellent biodegradability, to improve the water resistance, solvent resistance, airtightness, etc. of paper products, textile products, etc.
It can be used for impregnation, spraying, internal addition, etc.
In addition, the present invention provides a biodegradable resin aqueous dispersion excellent in stability over time with a small decrease in the molecular weight of the biodegradable resin dispersed in water, and a biodegradable composite material using the biodegradable resin aqueous dispersion. The purpose is to do.

[0006]

That is, an aqueous dispersion of a biodegradable resin of the present invention is characterized in that a polyester carbonate-based biodegradable resin is dispersed and stabilized in water. The aqueous biodegradable resin dispersion of the present invention preferably contains a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more as a dispersion stabilizer.

The biodegradable composite material of the present invention is characterized in that the biodegradable aqueous dispersion is compounded with a natural material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the aqueous biodegradable resin dispersion of the present invention, as the polyester polycarbonate resin used as the biodegradable resin, an aliphatic polymer such as a condensation polymer of 1,3-butanediol and succinic acid is used. Copolymers of polyesters with carbonates such as trimethylene carbonate and tetramethylene carbonate, and ring-opening copolymers of cyclic ethylene carbonate, trimethylene carbonate, 2,2-dimethyltrimethylene carbonate with ε-caprolactone, pivalolactone, etc. Is mentioned. Examples of such a polyester-polycarbonate-based biodegradable resin include “UPEC” manufactured by Mitsubishi Gas Chemical Co., Ltd. For the purpose of improving the physical properties and dispersion characteristics of the polyester polycarbonate-based biodegradable resin, other biodegradable resin constituent monomers may be copolymerized with the polyester polycarbonate-based biodegradable resin by a method such as graft polymerization, or The polyester polycarbonate-based biodegradable resin can also be used as a mixture with another biodegradable resin.

In the present invention, in order to stably disperse the biodegradable resin in water and form a stable dispersion, a cationic polymer compound having an average molecular weight of 300,000 or more or an average molecular weight is used as a dispersion stabilizer. It is preferable to contain 300,000 or more anionic polymer compounds, and it is more preferable to use polyvinyl alcohol in combination. As a dispersion stabilizer, a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more is 1: 0.001 to 0. In addition, when polyvinyl alcohol is used in combination, the weight ratio of a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more to polyvinyl alcohol is preferably used. , Average molecular weight 30
It is preferable to use at least 10,000 cationic polymer compounds or anionic polymer compounds having an average molecular weight of 300,000 or more: polyvinyl alcohol at a ratio of 8: 2 to 1: 9.

Examples of the cationic polymer compound include a cationic acrylic polymer and a cationic polyamine polymer. Examples of the cationic acrylic polymer include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl acrylate, dimethylaminomethyl methacrylamide, dimethyl Cationic acrylic monomers such as aminoethyl methacrylamide, dimethylaminopropyl methacrylamide, dimethylaminomethyl acrylamide, dimethylaminoethyl acrylamide, dimethylaminopropyl acrylamide, and alkylene, dialkyl sulfate, monochloroacetic acid And the like, for example, dimethylaminoethyl methyl methacrylate chloride salt, Acrylic acid diethylaminoethyl dimethyl sulfate, homopolymers and copolymers such as quaternary ammonium salts such as dimethylaminopropyl methacrylate chloroacetic acid salts.

As the copolymer, the above-mentioned cationic acrylic monomer and its quaternary ammonium salt, alkyl acrylate, hydroxyalkyl acrylate, polyoxyethylene acrylate, alkoxypolyoxyethylene acrylate, methacryl Acid alkyl ester, methacrylic acid hydroxyalkyl ester, methacrylic acid polyoxyethylene ester, methacrylic acid alkoxypolyoxyethylene ester, acrylamide, methacrylamide, dimethylacrylamide, diethylacrylamide, isopropylacrylamide, dimethylmethacrylamide, diethylmethacrylamide, methylolacrylamide, Acrylic monomers such as morpholylacrylamide, ethyl vinyl ether, Vinyl ethers such as cibutyl vinyl ether, triethylene glycol vinyl ether and methoxytriethylene glycol vinyl ether; allyl ethers such as hydroxyethyl allyl ether, tetraethylene glycol allyl ether and methoxyethylene glycol allyl ether; vinyl acetate; monochlorovinyl acetate; pivalic acid Carboxylic acid vinyl esters such as vinyl; vinylamines such as vinylpyridine, vinylimidazole and methylvinylimidazole; diallyl ammonium chloride; or having an unsaturated bond copolymerizable with the cationic acrylic monomer and its quaternary ammonium salt. Examples include a copolymer with a monomer.

As the cationic polyamine-based polymer,
Polyethylene imine, polypropylene imine, poly-3
Polymers of cyclic imines such as -methylpropylimine and poly-2-ethylpropylimine; polymers of unsaturated amines such as polyvinylamine and polyallylamine; and polyamine polymers such as quaternary ammonium salts thereof. . Further, those obtained by adding an alkyl group, a hydroxyalkyl group, an acyl group, a polyoxyalkylene group, a carboxyalkyl group, or the like to these polyamine-based polymers may also be used. The alkyl group is an alkyl halide, the hydroxyalkyl group is 1,2-epoxyalkane, the acyl group is an acyl halide, the polyoxyalkylene group is ethylene oxide, the carboxyalkyl group is monochloroacetic acid, acrylic acid, or the like. It can be added by reacting with a polymer.

The cationic high molecular compound is obtained by adding the above-mentioned cationic acrylic polymer and cationic polyamine polymer to oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid. , Dibasic acids such as sebacic acid, alkyl esters of these dibasic acids, diisocyanates such as hexamethylene diisocyanate glycidyl ether, diphenylmethane diisocyanate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, diglycidyl ether orthophthalate, etc. Polyepoxys, polyglycidyl ethers such as sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, urea, guanidines, diacid dihalides, dialde It may be obtained by cross-linking in the earth or.

In the present invention, when a copolymer of a cationic acrylic monomer and another monomer is used as the cationic polymer compound, the content of the cationic acrylic monomer in the cationic polymer compound is 30 mol%. It is preferable that it is above. The cationic polymer compound is usually preferably used as a salt of a suitable acidic compound. Examples of such an acidic compound include hydrochloric acid, sulfuric acid,
Any of inorganic acids such as formic acid and phosphoric acid, and organic acids such as acetic acid, oxalic acid, tartaric acid, malic acid, lactic acid, and benzoic acid may be used. Among them, acetic acid, phosphoric acid, and lactic acid are safety, price, heat stability, and coloring. It is preferable in terms of properties and the like. In the present invention, as the cationic polymer compound, a compound having an average molecular weight of 300,000 or more is selected from the above-mentioned compounds and used.

In the present invention, among the above-mentioned cationic polymer compounds, a monomer such as dimethylaminoethyl methacrylate or a neutralized product thereof, or a polymer mainly composed of at least one quaternary salt of these monomers is preferred.

On the other hand, as the anionic polymer compound,
Homopolymers of monomers such as unsaturated monocarboxylic acid monomers, unsaturated dicarboxylic acid monomers, unsaturated sulfonic acid monomers, copolymers of these monomers, and unsaturated monomers Monomers such as monocarboxylic acid monomers, unsaturated dicarboxylic acid monomers, unsaturated sulfonic acid monomers, and other copolymerizable monomers (hereinafter simply referred to as other monomers And the like.). Examples of unsaturated monocarboxylic acid monomers include acrylic acid, methacrylic acid, crotonic acid and neutralized and partially neutralized products of these acids, and unsaturated dicarboxylic acid monomers include maleic acid. Acids, fumaric acid, itaconic acid, citraconic acid and neutralized products of these acids, partially neutralized products, and the like.As the unsaturated sulfonic acid monomer,
Vinylsulfonic acid, allylsulfonic acid, methacrylsulfonic acid, styrenesulfonic acid, 2-acrylamide-2
-Methylpropanesulfonic acid, sulfoethyl (meth) acrylate, sulfoethylmaleimide, 3-allyloxy-2-hydroxypropanesulfonic acid, and neutralized and partially neutralized products thereof.

As the anionic polymer compound, a monomer such as the above-mentioned unsaturated monocarboxylic acid-based monomer, unsaturated dicarboxylic acid-based monomer, unsaturated sulfonic acid-based monomer and other monomers may be used. When a copolymer of (1) is used, other monomers are not particularly limited. For example, amide monomers such as (meth) acrylamide, isopropylamide, t-butyl (meth) acrylamide, and (meth) acrylic acid Alkyl esters,
Styrene, 2-methylstyrene, hydrophobic monomers such as vinyl acetate, 2-hydroxyethyl (meth) acrylate,
Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, allyl alcohol, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, 3-methyl-3-buten-1-ol (isoprenol), polyethylene glycol monoisoprop Lenol ether, polypropylene glycol monoisoprenol ether, 3-methyl-2-buten-1-ol (prenol), polyethylene glycol monoprenol ester, polypropylene glycol monoprenol ester, 2-methyl-3-buten-2-ol (Isoprene alcohol), polyethylene glycol monoisoprene alcohol ether, polypropylene glycol monoisoprene alcohol Ether, N- methylol (meth)
Hydroxyl-containing monomers such as acrylamide, glycerol monoallyl ether, and vinyl alcohol; (meth) acrylamide methanephosphonic acid; methyl (meth) acrylamide methanephosphonate; 2- (meth) acrylamide-2-methylpropanephosphonic acid; Examples include a phosphorus-containing monomer, methoxypolyethylene glycol (meth) acrylate, and ethoxypropylene glycol (meth) acrylate.

[0018] The anionic polymer compound includes the unsaturated monocarboxylic acid monomer, unsaturated dicarboxylic acid monomer,
In addition to homopolymers of monomers such as unsaturated sulfonic acid monomers, copolymers of these monomers, and copolymers of these monomers with other monomers, Acid, malonic acid,
Dibasic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,
Alkyl esters of these dibasic acids, diisocyanates such as hexamethylene diisocyanate glycidyl ether, diphenylmethane diisocyanate, diepoxys such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and orthophthalic acid diglycidyl ether; sorbitan polyglycidyl ether; It may be crosslinked with polyglycidyl ethers such as methylolpropane polyglycidyl ether, urea, guanidines, dibasic acid dihalides, dialdehydes and the like.

The anionic polymer compound is usually preferably used as a salt of a suitable basic compound. Examples of such a basic compound include an alkali metal hydroxide, an alkaline earth metal hydroxide, and the like. Amine compounds such as monoethanolamine and diisopropanolamine, and ammonia are used.

As the anionic polymer compound, those having an average molecular weight of 300,000 or more are selected from the above-mentioned compounds and used. Among the above-mentioned anionic polymer compounds, a polymer mainly composed of at least one of methacrylic acid and a neutralized product thereof is preferable.

As the dispersion stabilizer, the above-mentioned cationic polymer compound having an average molecular weight of 300,000 or more or an average molecular weight of 3
When the anionic polymer compound having a molecular weight of 0000 or more and polyvinyl alcohol are used in combination, the polyvinyl alcohol preferably has a saponification degree of 70 to 90% and an average molecular weight of 50,000 to 300,000.

The average molecular weight of the cationic polymer compound, anionic polymer compound and polyvinyl alcohol is as follows:
Mean number average molecular weight. The saponification degree of polyvinyl alcohol can be calculated from the hydroxyl value of polyvinyl alcohol.

In the present invention, the cationic polymer compound having an average molecular weight of 300,000 or more or the anionic polymer compound having an average molecular weight of 300,000 or more and polyvinyl alcohol are used in a weight ratio of the cationic polymer compound or the anionic polymer. By using the compound: polyvinyl alcohol at a ratio of 8: 2 to 1: 9, the polyester polycarbonate-based biodegradable resin can be more stably dispersed in water.

The aqueous biodegradable resin emulsion of the present invention may further comprise a thickener, a surface smoothing agent, a release agent, a water repellent (hydrophobicity improver), and a rust inhibitor in addition to the above components, if necessary. , A fluidity regulator, a plasticizer, a coloring agent, and the like can be contained.As the thickening agent, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, cellulose derivatives such as hydroxypropylmethylcellulose, cationized starch,
Examples include starch derivatives such as etherified starch, plant gums such as gum arabic, guar gum, and xanthan gum; and animal polymers such as casein, chitosan, and chitin. On the other hand, in order to improve the surface smoothness, the releasability, the water repellency, etc., a wax such as a natural wax or a synthetic wax can be contained. Examples of natural waxes include plant natural waxes such as candelilla wax, carnauba wax, rice wax, wood wax, jojoba solid wax, and animal natural waxes such as beeswax, lanolin, and whale wax, montan wax, ozokerite, ceresin, and other minerals. System natural wax,
Paraffin wax, microcrystalline wax,
And petroleum waxes such as petrolatum wax. Examples of the synthetic wax include synthetic hydrocarbons such as Fischer-Tropsch wax and polyethylene wax, denatured waxes such as montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives; hydrogenated waxes such as hardened castor oil and hardened castor oil derivatives; -Hydroxystearic acid, stearic acid amide, phthalic anhydride and the like.

[0025] The aqueous biodegradable resin dispersion of the present invention comprises paper,
Combined with animal and plant materials such as pulp, nonwoven fabric, woven fabric, knitted fabric, and leather products of animal and plant fibers, natural resins such as starch resin and polylactic acid resin, and natural materials such as inorganic minerals such as clay and sand By doing so, the water / oil repellency, water resistance, airtightness, surface gloss and the like of these products can be improved. The natural material may be in any form such as a sheet, a plate, a nonwoven fabric, a woven fabric, a knitted fabric, a molded product, a powder, a granular material, a crushed material, a slurry, and a paste. Sheets made of natural materials,
In the case of plate-like materials, non-woven fabrics, woven fabrics, knitted fabrics, molded products, etc., as a compounding method, the aqueous dispersion of the present invention is applied or sprayed on the surface of these natural materials, And then heating and pressurizing with a heating roll, a press, a mold or the like. When the natural material is a powder, a granular material, a crushed material, a slurry, a paste, or the like, after adding and mixing the aqueous biodegradable resin dispersion of the present invention to these natural materials, heating, pressurizing, etc. It may be compounded by a method. For example, if the natural material is wood chips, after mixing the wood chips and the aqueous biodegradable resin dispersion,
The wood and the polyester-polycarbonate-based biodegradable resin can be compounded by filling in a mold and hot pressing. Further, for example, when the natural material is pulp, the pulp and the polyester polycarbonate-based biodegradable resin can be composited by adding an aqueous dispersion of the biodegradable resin to the pulp slurry and papermaking.

When the aqueous biodegradable resin dispersion of the present invention is used to enhance the water resistance, solvent resistance, etc. of a product made of a natural material, natural wax and / or a hydrophobicity improver are used as a release / hydrophobicity improver. It preferably contains a synthetic wax. When natural waxes and / or synthetic waxes are contained, the product can be further improved in water repellency and oil repellency, water resistance, oil resistance, airtightness, and the like. It is preferable because the releasability from a mold or the like is improved.

The aqueous biodegradable resin dispersion of the present invention can be used, for example, as a dispersion stabilizer, a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more, and polyvinyl alcohol. When used together, in a closed tank having a stirring device, a polyester polycarbonate-based biodegradable resin, a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more, polyvinyl alcohol, and A pressure dispersion method in which water is simultaneously charged and the biodegradable resin is dispersed by pressurizing while heating and stirring, the biodegradable resin, the cationic polymer compound or the anionic high A direct dispersion method in which a melt containing a molecular compound and polyvinyl alcohol is added and stirred for dispersion, and a biodegradable resin is dissolved in an organic solvent Is added and stirred in an aqueous solution containing a cationic polymer compound or an anionic polymer compound and polyvinyl alcohol, and then dispersed.Then, the organic solvent is removed, and the biodegradable resin is heated and melted. An aqueous solution containing a polymer compound or an anionic polymer compound and polyvinyl alcohol can be added and stirred to disperse the biodegradable resin in water.

Any method other than the above can be appropriately employed as long as it can obtain an aqueous dispersion of the biodegradable resin. However, the method can be applied to a wide variety of biodegradable resins. It is preferable to disperse the resulting organic solvent solution of the biodegradable resin in water to which a cationic polymer compound or an anionic polymer compound and polyvinyl alcohol have been added, if necessary, with stirring. When preparing the aqueous dispersion, a dispersing device such as a high-pressure homogenizer may be used together if necessary.

[0029]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

Examples 1 to 9 A biodegradable resin, a cationic polymer compound or an anionic polymer compound shown in Table 1, polyvinyl alcohol, deionized water, and ethyl acetate were charged into an autoclave at a ratio shown in the same table. After heating to ℃ and stirring at 5,000 rpm for 1 minute, the mixture was cooled to 40 ° C. while stirring at 400 rpm to obtain an aqueous dispersion of a biodegradable resin. When a cationic polymer compound is used, the pH is adjusted to 6 with acetic acid when the pH is 6 or more, and when an anionic polymer compound is used, the pH is adjusted with sodium hydroxide when the pH is 8 or less. And then heated and stirred. In order to compare the particle size of the biodegradable resin dispersed in each of the obtained aqueous dispersions, a particle size distribution measuring apparatus (manufactured by Horiba, Ltd .: LA-910 type particle size distribution measurement) was used immediately after the aqueous dispersion was produced. The particle size of the biodegradable resin dispersed in the apparatus was measured. Further, this aqueous dispersion was held in an atmosphere of 20 ° C. and 40 ° C., and the temporal stability of the aqueous dispersion at each temperature was evaluated. The results are shown in Table 1.

[0031]

[Table 1]

The stability of the aqueous dispersion shown in Table 1 was 10
50 ml of the aqueous dispersion is placed in a 0 ml screw tube,
After standing in a thermostat at 0 ° C. and 40 ° C., one month later and 2
The dispersed state after one month is visually observed. ◎: No separation is observed.・ ・ ・: Separation is observed, but generation of precipitate is not observed. Δ: Separation and sedimentation are observed, but when the screw tube is turned over and re-established 10 times, it is redispersed and becomes uniform. X: Separation and sedimentation were observed, and the sediment became a hard cake, and the screw tube did not re-disperse even if the screw tube was turned over and re-established 10 times. Was evaluated. Further, the acid value of the aqueous dispersion immediately after preparation and after standing at 40 ° C. for 2 months was measured based on a standard fat and oil analysis method, and an increase in carboxyl groups caused by hydrolysis of ester bonds in the resin was observed.

The biodegradable resins, cationic polymer compounds, anionic polymer compounds and the like shown in Table 1 are as follows.

(1) Biodegradable Degradable Resin Biodegradable Resin A: Commercially available polyester polycarbonate resin (melting point: 106 ° C., MFR 15 g / 10 min) Biodegradable resin B: Commercially available polyester polycarbonate resin (melting point: 99 ° C., MFR) 7 g / 10 min) Biodegradable resin C: polylactic acid resin having an L-form purity of 98% and an average molecular weight of 150,000 (melting point: 172 ° C., MFR: 2 g / 10 mi)
n) * MFR conforms to JIS K-7210. Measurement conditions: 1
90 ° C, load 2160g

(2) Cationic polymer compound Cation A: dimethylaminoethyl methacrylate / acrylamide (80:20 by weight ratio) copolymer (cationization degree: 68%, average molecular weight: 6,300,000). Cation B: diethylaminoethyl methacrylate / acrylamide / methacrylamide (weight ratio 93: 5:
2) copolymer (cationization degree 82%, average molecular weight 530)
10,000) Cation C: dimethylaminoethyl acrylate / acrylamide / methacrylamide (weight ratio: 33:38:
29) Copolymer (Cation degree 20%, average molecular weight 23)
Ten thousand)

(3) Anionic polymer compound Anion A: acrylamide / methacrylic acid (90:10 by weight ratio) copolymer (average molecular weight 8.2 million) Anion B: acrylamide / methacrylamide / methacrylic acid (weight ratio: 55) : 10:35) Copolymer (average molecular weight 65.5 million) Anion C: Acrylamide / methacrylic acid / acrylic acid (70:10:20 by weight ratio) copolymer (average molecular weight 220,000)

(4) Polyvinyl alcohol PVA-A: saponification degree 80.3%, average molecular weight 200,000 PVA-B: saponification degree 86.9%, average molecular weight 160,000 PVA-C: saponification degree 75.0%, average Molecular weight 80,000

Each of the emulsions of Examples 1 to 6 and Comparative Examples 1 to 3 was coated on neutral high-quality paper (basis weight 70 g / m ² ) with a bar coater No. 10 and dried in a hot air dryer at 40 ° C. for 30 minutes, sandwiched between ferro-plates, and fully automated transfer press manufactured by Hashima Co., Ltd .: HP-84 at 180 ° C., 200 ° C.
Pressing was performed for 1 minute under the conditions of g / cm ² . Next, the treated paper is treated at 20 ° C. and 6 in accordance with JIS P-8111.
After pretreatment with 0% RH, water repellency, oil repellency, surface gloss,
Biodegradability was measured. The results are shown in Table 2 together with the results for untreated neutral high-quality paper. The same evaluation was performed after the used emulsion was allowed to stand in a constant temperature bath at 40 ° C. for 2 months.
Table 3 shows the results.

[0039]

[Table 2]

[0040]

[Table 3]

* 1: The water repellency was indicated by the water absorption after 5 minutes according to JIS-P-8140. * 2: Oil repellency is measured by TAPPI paper pulp test method No. 40
It measured according to. * 3: Surface gloss was measured according to JIS-8142. * 4: The biodegradability is as follows: Coated paper sandwiched between two polypropylene nets is buried in the soil of 10cm to 30cm on the surface of the Nagoya Plant of Miyoshi Oil & Fat Co., Ltd. in Iwakura City, Aichi Prefecture for 6 months The case where it completely disappeared later was evaluated as ○, and the case where a part of the coated paper remained was evaluated as ×.

[0042]

As described above, the biodegradable aqueous dispersion of the present invention comprises a polyester-polycarbonate-based biodegradable resin, which is optionally a cationic polymer compound having an average molecular weight of 300,000 or more or an average molecular weight of 300,000 or more. Anionic polymer compound, or cationic polymer compound having an average molecular weight of 300,000 or more or anionic polymer compound having an average molecular weight of 300,000 or more, and dispersed in water in the presence of a mixture of polyvinyl alcohol and a specific ratio. And an aqueous dispersion having excellent dispersion stability. Since the aqueous biodegradable resin dispersion of the present invention uses a polyester polycarbonate that is not easily hydrolyzed, the biodegradable resin fine particles dispersed in the aqueous dispersion may be hydrolyzed to lower the molecular weight. And has excellent performance stability such as little change in physical properties due to aging. In addition, the aqueous biodegradable resin dispersion of the present invention is easily decomposed by microorganisms in nature, so by applying the dispersion of the present invention to cloth products and paper products, cloth products, water resistance of paper products, Oil resistance, airtightness, etc. can be improved, and even when these cloth products and paper products are buried and discarded, they are easily decomposed by microorganisms, and there is no risk of polluting the environment. The biodegradable composite material of the present invention, which is obtained by compounding a degradable aqueous dispersion with a natural material, has effects such as exhibiting excellent water resistance, oil resistance, and the like, in addition to excellent biodegradability.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsuhisa Kamio 1 at Nishiide, Noyoro-cho, Iwakura-shi, Aichi Prefecture Inside Nagoya Plant of Miyoshi Oil & Fats Co., Ltd. (72) Inventor Kazuo Hosoda 4-66 Horikiri, Katsushika-ku, Tokyo No. 1 Miyoshi Yushi Co., Ltd. F term (reference) 4F070 AA47 AB11 AC80 AC83 AE14 CA03 CB01 4F100 AJ00B AK41A BA02 BA07 CA05A JA07A JC00A YY00A 4J002 AB01Z AB04Z AC02X AD00Z AH00Z BC04X02BG04 BE02 BG02X04 BQ00X CF18Z CG00W CH05X CM01X DJ006 DJ016 FD20X FD20Y FD31X FD31Y GF00 GH00 GK02 GK04

Claims (3)

[Claims] An aqueous dispersion of a biodegradable resin, wherein the polyester carbonate-based biodegradable resin is dispersed and stabilized in water. 2. The aqueous biodegradable resin dispersion according to claim 1, which contains a cationic polymer compound having an average molecular weight of 300,000 or more or an anionic polymer compound having an average molecular weight of 300,000 or more as a dispersion stabilizer. 3. A biodegradable composite material comprising the biodegradable aqueous dispersion according to claim 1 and a natural material.