JP2002129042A - Modifying agent for biodegradable resin and biodegradable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable resin composition, improved in resin- melting property regardless of molecular weight of the biodegradable resin to be used, and excellent in moldability without damage of an surface appearance of a molded product, and provide a modifying agent therefore. SOLUTION: A mixed powder (B), having polytetrafluoroethylene composed of polytetrafluoroethylene particle having a diameter of 10 μm or less and an organic polymer, is blended so that the content of polytetrafluoroethylene component is 0.01-20 mass parts to 100 mass parts of the biodegradable resin (A). The degradable resin composition, improved in resin-melting property, and excellent in moldability without damage of the surface appearance, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable resin composition, and more particularly to a composition having improved moldability.

[0002]

2. Description of the Related Art In recent years, polyethylene, polypropylene,
A huge amount of plastic products such as polystyrene, polyethylene terephthalate, and vinyl chloride are used,
These waste treatments have been highlighted as one of the environmental problems. That is, the current waste treatment is incineration or burial treatment. For example, incineration of polyethylene or the like results in high burned calories, which damages the incinerator and shortens its life. Also, for example, polyvinyl chloride is not suitable for incineration. On the other hand, land is limited for burying plastic products. Also, when discarded in the natural environment, they have extremely high chemical stability and biologically hardly decompose by microorganisms, etc.,
It will remain almost semi-permanently. For this reason, not only is the landscape damaged, but also the pollution of the living environment of marine life is caused. Therefore, from the viewpoint of environmental protection, a polymer that is biodegradable or decomposes in a natural environment has attracted much attention today. It is known that biodegradable plastics gradually decompose and decompose in soil or water due to hydrolysis or biodegradation, and eventually become harmless decomposition products due to the action of microorganisms. Currently, biodegradable plastics that are being considered for practical use include biocellulose based on natural materials, plastics mainly composed of starch, aliphatic polyester, modified PVA (polyvinyl alcohol), cellulose ester compounds, modified starch, and blends thereof. It is roughly divided into the body. Among these, aliphatic polyester resins are relatively well-balanced in terms of workability, cost, mechanical properties, water resistance, etc., and are attracting attention as resins that are easy to use in various applications.
Examples of the aliphatic polyester include, for example, poly (hydroxybutyric acid / valeric acid) as a microorganism-producing polymer, polycaprolactone or a condensate of an aliphatic dicarboxylic acid and an aliphatic diol as a synthetic polymer, and a semi-synthetic polymer. Polylactic acid-based polymers are known as polymers.

[0003]

However, aliphatic polyesters are difficult to obtain melting properties suitable for molding due to their crystalline nature and the difficulty in obtaining high-molecular-weight polymers for practical use. Therefore, several methods for improving the moldability of the aliphatic polyester have been proposed. For example, Japanese Patent Application Laid-Open No. 4-189822 discloses a method of reacting a high-molecular-weight aliphatic polyester with a specific amount of diisocyanate or polyisocyanate, and further increasing the molecular weight to a practically usable high-molecular region. . JP-A-6-298920 discloses that a small amount of an unsaturated group is introduced into a polyester, and an organic peroxide is added to the obtained unsaturated aliphatic polyester in a molten state of the polyester to obtain an unsaturated polyester in the polyester. A method for obtaining a high molecular weight aliphatic polyester by adding saturated groups to each other is disclosed. JP 2000-015765
The gazette discloses a method of subjecting a lactone resin such as polycaprolactone to radiation treatment to generate cross-linking points. However, at present, sufficient moldability has not been obtained by these methods. Also, by increasing the molecular weight,
Increased production costs due to an increase in the number of polymer production steps and a decrease in productivity, and the fact that a gel resin having a size of 0.1 to several millimeters, which is called a microgel, is easily mixed into the produced polymer, It has been pointed out that the appearance is significantly reduced. Furthermore, it has been recognized that when a urethane bond is introduced into a resin molecule as described above, the biodegradability by microorganisms usually decreases.

[0004] As additives for improving the melting properties of resins,
Polytetrafluoroethylene is known, for example, as disclosed in JP-A-5-214184 and JP-A-6-306212.
In Japanese Patent Application Laid-Open Publication No. H11-157, a resin composition obtained by blending polytetrafluoroethylene with a polyolefin resin is disclosed. A mixture of a biodegradable resin, an aliphatic polyester resin and polytetrafluoroethylene powder is disclosed in JP-A-10-1.
No. 52572. However, polytetrafluoroethylene has poor dispersibility with respect to a general thermoplastic resin containing no halogen atom, and has a drawback that the surface appearance of a molded article is remarkably deteriorated even if it is simply mixed, without being uniformly dispersed. are doing

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to improve the melting characteristics of a resin regardless of the molecular weight of the biodegradable resin to be used and to improve the molding without impairing the surface appearance of a molded product. An object of the present invention is to obtain a biodegradable resin composition excellent in processing and a modifier therefor.

[0006]

Means for Solving the Problems As a result of diligent studies to solve the above problems, it has been found that the dispersibility of polytetrafluoroethylene in a biodegradable resin is enhanced, that is, polytetrafluoroethylene having a particle diameter of 10 μm or less. By adding a polytetrafluoroethylene-containing mixed powder composed of fluoroethylene particles and an organic polymer to a biodegradable resin, it improves the melting properties of the resin, and has good moldability and excellent appearance. And arrived at the present invention.

The modifier for a biodegradable resin of the present invention is characterized in that it has a polytetrafluoroethylene-containing mixed powder containing polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer. Things. In the biodegradable resin composition of the present invention, the amount of the polytetrafluoroethylene component is 0.01 to 20 parts by mass based on 100 parts by mass of the biodegradable resin (A). It is characterized by being blended. Here, it is desirable that the main component of the biodegradable resin (A) is an aliphatic polyester resin. Further, it is preferable that the main component of the aliphatic polyester resin is polycaprolactone, which is obtained by a reaction mainly containing polylactic acid, an aliphatic glycol and an aliphatic dicarboxylic acid or a derivative thereof. Further, as the biodegradable resin (A), a biodegradable resin (C) other than the aliphatic polyester resin can be contained, and the biodegradable resin (C) includes a biodegradable cellulose ester, Peptide, polyvinyl alcohol, starch, cellulose, paper, pulp, carrageenan,
Chitin / chitosan, natural linear polyester resin,
Alternatively, at least one selected from a mixture thereof is preferable. Further, as the biodegradable resin composition, a master pellet having the biodegradable resin (A) and the above-mentioned modifier is further blended into the biodegradable resin (A), and the biodegradable resin (A) ), The amount of the polytetrafluoroethylene component is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass in total.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The biodegradable resin modifier of the present invention contains polytetrafluoroethylene (hereinafter referred to as PTFE) particles having a particle diameter of 10 μm or less and an organic polymer. The proportion of PTFE in the modifier containing polytetrafluoroethylene particles is preferably from 0.1 to 90% by mass.
When the amount is less than 0.1% by mass, the effect of adding a modifier containing polytetrafluoroethylene particles is not obtained when blended with the biodegradable resin, and when the amount exceeds 90% by mass, polytetrafluoroethylene particles are contained. PTFE particles in the modifier aggregate,
Dispersion into other biodegradable resins becomes difficult.

The organic polymer constituting the modifier containing the polytetrafluoroethylene particles is different from the biodegradable resin containing the modifier containing the polytetrafluoroethylene particles.
From the viewpoint of the dispersibility of PTFE, it is preferable that the resin has affinity for the biodegradable resin to be mixed.

Specific examples of the monomer for forming the organic polymer include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, and o-methoxystyrene. Styrene monomers such as styrene, 2,4-dimethylstyrene, and a-methylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylate-2- (Meth) acrylic ester such as ethylhexyl, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, etc. Monomer; acrylonitrile, methac Vinyl cyanide monomers such as rilonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ether; vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; olefin monomers such as ethylene, propylene and isobutylene Diene monomers such as butadiene, isobrene, and dimethylbutadiene. These monomers can be used alone or in combination of two or more.

For example, when the biodegradable resin in which the modifier containing the PTFE-containing polytetrafluoroethylene particles of the present invention is blended is polyester, styrene is preferred among these monomers from the viewpoint of compatibility. And those containing 20% by mass or more of a (meth) acrylate monomer.

Examples of the method for producing an aqueous dispersion of organic polymer particles used in the present invention include an emulsion polymerization method using an ionic emulsifier, a soap-free emulsion polymerization method using an ionic polymerization initiator, and the like. . As the ionic emulsifier, any of an anionic emulsifier, a cationic emulsifier, and a zwitterionic emulsifier may be used. If desired, a nonionic emulsifier may be used in combination with these ionic emulsifiers. Specific examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of aliphatic amines and aliphatic amides, fatty alcohol phosphates, and dibasic fatty acid esters. Sulfonates, fatty acid amide sulfonates, alkylallyl sulfonates, and naphthalene sulfonates of formalin condensate can be mentioned. Specific examples of the cationic emulsifier include aliphatic amine salts, quaternary ammonium salts, and alkylpyridinium salts. Specific examples of the amphoteric ion emulsifier include alkyl betaine. Examples of the ionic polymerization initiator include persulfates (for example, potassium persulfate and ammonium persulfate), azobis (isobutyronitrile sulfonate), and 4,4′-azobis (4
-Cyanovaleric acid) and other anionic polymerization initiators, 2,2'-
Azobis (amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2
-Imidazolin-2-yl) propane] dihydrochloride, 2,
Cationic polymerization initiators such as 2'-azobisisobutylamide dihydrate can be exemplified. Particle diameter d of the organic polymer particles used in the present invention, from the viewpoint of the stability of the aggregation state with the polytetrafluoroethylene particles, those having the following formula with respect to the particle diameter D of the polytetrafluoroethylene particles. preferable. 0.1D <d <10D

The polytetrafluoroethylene-containing mixed powder of the present invention is obtained by mixing a polytetrafluoroethylene particle dispersion and an organic polymer particle dispersion and pulverizing them by coagulation or spray drying. It includes agglomerated particles in which fluoroethylene particles and organic polymer particles are agglomerated due to a difference in surface charge, and each single particle remaining without being agglomerated. The agglomerated particles have a structure in which polytetrafluoroethylene particles and organic polymer particles are integrated, and the morphology thereof may be various depending on the mixing ratio of both particles and the particle size. That is, a form in which the organic polymer surrounds the polytetrafluoroethylene particles, a form in which the polytetrafluoroethylene particles surround the organic polymer particles, and a few particles for one particle. Are present in the form of aggregates. At this time, if only the polytetrafluoroethylene particles aggregate to form an aggregate of 10 μm or more, it is not preferable from the viewpoint of dispersibility in the biodegradable resin. Before mixing, the nonionic emulsifier is mixed with polytetrafluoroethylene particles and / or a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms in order to reduce the aggregation rate during mixing. ) It can be adsorbed on the surface of the polymer particles. The nonionic emulsifier is not particularly limited, and specific examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, dialkylphenoxypoly (ethyleneoxy) ethanol, polyvinyl alcohol, polyacrylic acid, and alkyl cellulose. .

The polytetrafluoroethylene-containing mixed powder of the present invention is prepared by mixing the above-mentioned polytetrafluoroethylene particle dispersion and the organic polymer particle dispersion in a dispersion.
It can also be obtained by emulsion polymerization of a monomer having an ethylenically unsaturated bond and pulverization by coagulation or spray drying. As the ethylenically unsaturated monomer to be emulsion-polymerized in the mixed dispersion, styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene,
styrene-based monomers such as o-chlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene, α-methylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate; Acrylate monomers such as butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate; acrylonitrile; Vinyl cyanide monomers such as methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; ethylene, propylene, isobutylene and the like Olef Emissions monomers; butadiene, isoprene, may be selected Puren, from such diene monomer dimethyl butadiene. These monomers are
They can be used alone or in combination of two or more.

In the polytetrafluoroethylene-containing mixed powder of the present invention, the aqueous dispersion is poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved, salted out, coagulated and dried. It can be powderized by spray drying. Although ordinary polytetrafluoroethylene fine powder becomes an aggregate of 100 μm or more in the process of recovering as a powder from the state of a particle dispersion, it is difficult to uniformly disperse it in a biodegradable resin. On the other hand, the polytetrafluoroethylene-containing mixed powder of the present invention is extremely excellent in dispersibility in a biodegradable resin because polytetrafluoroethylene alone does not form a domain having a particle diameter of more than 10 μm.

The modifier of the present invention having a polytetrafluoroethylene-containing mixed powder containing an organic polymer and polytetrafluoroethylene particles having a particle diameter of 10 μm or less is used with respect to 100 parts by mass of a biodegradable resin. It is preferable that the amount of the polytetrafluoroethylene component is 0.01 to 20 parts by mass. 0.05 to 20 parts by mass is more preferable, and 0.1 to 5 parts by mass is more preferable. If the amount is less than 0.01 part by mass, the modifying effect is not sufficient, and if it is more than 20 parts by mass, the fluidity of the resin tends to deteriorate, and the moldability tends to deteriorate. The method of adding the modifier to the biodegradable resin is not particularly limited,
It can be performed by a conventionally known method. For example, mixing and kneading may be performed using a mill roll, a Banbury mixer, a super mixer, a single screw or twin screw extruder, or the like.
In addition to the addition at a time, a master pellet may be formed by using a part of the biodegradable resin and a modifier, and then blended with the remaining biodegradable resin.

The biodegradable resin (A) in the present invention includes polysaccharides (starch, cellulose acetate, etc.), polyethers such as polyethylene glycol / propylene glycol; polycarbonates such as polyhexamethylene carbonate; polyγ-methyl L- Polyamides such as glutamate; and aliphatic polyesters. These may be used in combination of two or more. Among these, it is preferable to use an aliphatic polyester as a main component. In the present invention, the term “main component” means that the ratio accounts for more than half. Examples of the aliphatic polyester include, for example, poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid; poly (β-hydroxyalkanoate) such as poly-β-hydroxybutyric acid; and poly (β-hydroxyalkanoate) such as poly-ε-caprolactone. ω-
Hydroxyalkanoate); and polyalkylene alkanoates such as polybutylene succinate and polyethylene succinate. These two or more aliphatic polyesters can be used in combination. Among them, those containing a polylactic acid-based, polyalkylenealkanoate-based or polycaprolactone-based aliphatic polyester as a main component are preferable. These aliphatic polyesters are not particularly limited, but generally have a melting point of 60 to 200 ° C. and a weight average molecular weight of 50,000 to 500,000, preferably about 100,000 to 300,000 in the case of crystallinity.

The polylactic acid-based polymer in the present invention is polylactic acid, a copolymer of lactic acid and another hydroxycarboxylic acid, or a mixture thereof. As lactic acid,
L-lactic acid and D-lactic acid are mentioned, and as other hydroxycarboxylic acids, glycolic acid, 3-hydroxybutyric acid, 4
-Hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid and the like. Polylactic acid can be synthesized by a conventionally known method. That is, Japanese Patent Application Laid-Open No. 7-33861,
No. 9-96123, Proceedings of the Society of Polymer Symposium, 44, 31
It can be synthesized by direct dehydration condensation from lactic acid as described on page 98-3199, or ring-opening polymerization of lactic acid cyclic dimer lactide. When performing direct dehydration condensation, any lactic acid of L-lactic acid, D-lactic acid, DL-lactic acid, or a mixture thereof may be used. Also, in the case of performing ring-opening polymerization, any lactide of L-lactide, D-lactide, DL-lactide, meso-lactide or a mixture thereof may be used. Lactide synthesis, purification and polymerization procedures are described, for example, in US Pat. No. 4,057,537, published European Patent Application No. 261572, Polymer Bullet.
in, 14, 491-495 (1985), and Makromol Chem., 187,
It is described variously in literatures such as 1611-1628 (1986).
The constituent molar ratio L / D of the L-lactic acid unit and the D-lactic acid unit in the polylactic acid may be any of 100/0 to 0/100, but the L / D is preferably 100/0 to 60/40. . More preferable L / D is 100/0 to 80/20.
It is. The lactic acid copolymer is obtained by copolymerizing another component copolymerizable with a lactic acid monomer or lactide. Examples of such other components include dicarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, and lactones having two or more ester bond-forming functional groups.
Examples of the dicarboxylic acid include succinic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid.
Polyhydric alcohols include aromatic polyhydric alcohols such as those obtained by adding ethylene oxide to bisphenol, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, glycerin, sorbitan, trimethylolpropane, neopentyl glycol, etc. Aliphatic polyhydric alcohols, ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol. Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutylcarboxylic acid, and those described in JP-A-6-184417. Examples of the lactone include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β-
Or γ-butyrolactone, pivalolactone, δ-valerolactone and the like. The hydrolyzability of a lactic acid copolymer is affected by the content of lactic acid units in the copolymer. For this reason, the content of lactic acid units in the lactic acid copolymer is generally 50 mol% or more, preferably 70 mol% or more, although it depends on the copolymerization component used. The mechanical properties and biodegradability of the obtained product can be adjusted by the content of the lactic acid unit and the copolymer component. In addition, polylactic acid and another aliphatic polyester may be simply blended for the purpose of obtaining the same effect as the copolymerization. In this case,
The monomers and polylactic acid content of other aliphatic polyesters are the same as in the case of copolymerization.

As the polyalkylene alkanoate-based aliphatic polyester resin, a resin obtained by reacting an aliphatic glycol with an aliphatic dicarboxylic acid or a derivative thereof as a main component is preferable. Any one may be used as long as the obtained copolymer has good biodegradability. Such polyesters include, for example, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and ethylene glycol, 1,4-butanediol,
Aliphatic polyesters comprising aliphatic diols such as 6-hexanediol and 1,8-octanediol;
Constituents are aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatic diols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,8-octanediol. Aromatic polyester; examples thereof include aliphatic aromatic polyesters composed of the above-mentioned aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic diols. Preferred polyalkylene alkanoate-based aliphatic polyesters include polyethylene oxalate, polybutylene oxalate, polyneopentyl glycol oxalate, polyethylene succinate,
Polybutylene succinate, polyhydroxybutyric acid and β
And a copolymer of -hydroxybutyric acid and β-hydroxyvaleric acid, and polyethylene succinate and polybutylene succinate are particularly preferred. The present aliphatic polyester resin may be one containing a hydroxycarboxylic acid, a lactone or the like as a constituent component. Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutylcarboxylic acid, and those described in JP-A-6-184417. Lactones include glycolide, ε-
Caprolactone glycolide, ε-caprolactone, β-
Propiolactone, δ-butyrolactone, β- or γ
-Butyrolactone, pivalolactone, δ-valerolactone and the like. These aliphatic polyesters may have a urethane bond in the polymer chain by a binder such as diisocyanate, and the polymer chain may be extended, or a small amount of an aliphatic polyvalent such as glycerin. Alcohols, aliphatic polybasic acids such as butanetetracarboxylic acid, and polyhydric alcohols such as polysaccharides may coexist and be copolymerized.

The polycaprolactone used in the present invention is
For example, it can be obtained by subjecting ε-caprolactone to ring-opening polymerization in a conventional manner using active hydrogen such as alcohol as an initiator. The functional number of the initiator is not particularly limited, and bifunctional or trifunctional ones can be preferably used. The molecular weight of polycaprolactone can be used from low molecular weight to high molecular weight, but when using low molecular weight polycaprolactone, the amount of addition is limited because the heat resistance and mechanical strength of the kneaded resin decrease greatly. Merits such as a decrease in the melt viscosity of the composition and an improvement in moldability appear. However, it is more preferable to use polycaprolactone having a high molecular weight, since the compounding ratio can be increased, and all of heat resistance, mechanical properties, and biodegradability can be highly balanced. Specifically, the number average molecular weight is 1,000-20.
A polycaprolactone of 000, more preferably 5,000 to 100,000 can be preferably used. Note that 200,0
Although those having a number average molecular weight higher than 00 can be used without problems, it is difficult to obtain such a polycaprolactone having a very high molecular weight, which is not practical. Further, the polycaprolactone to be used includes, in addition to ε-caprolactone homopolymer, comonomer constituent units such as valerolactone, glycolide, and lactide, for example, 20
Copolymers containing less than mol% can also be used.

The aliphatic polyester resin used in the present invention can be made high molecular weight by, for example, a conventionally known method as described below. (A) A method using an isocyanate coupling agent. Aliphatic dicarboxylic acid and aliphatic glycol, 3 as the third component
A polyisocyanate is used for an aliphatic polyester obtained by adding at least one polyfunctional component selected from a functional or tetrafunctional polyhydric alcohol, an oxycarboxylic acid, and a polycarboxylic acid (or an anhydride thereof). To produce an aliphatic polyester (JP-A-6-192374). (B) A method using an unsaturated dicarboxylic acid. Reaction of an aliphatic or cycloaliphatic glycol component with an acid component comprising 98 to 99.99 mol% of an aliphatic dicarboxylic acid or an acid anhydride thereof and 0.01 to 2 mol% of an unsaturated dicarboxylic acid or an acid anhydride thereof. The organic peroxide was added to 0.005 parts by mass of the unsaturated aliphatic polyester thus obtained.
-0.1 parts by mass, preferably 0.005 parts by mass or more, 0.1 parts by mass.
Less than 01 parts by mass is added and reacted to produce a high molecular weight aliphatic polyester (JP-A-6-298920). (C) A method using an unsaturated isocyanate. An aliphatic polyester is obtained by reacting a glycol component comprising an even-numbered glycol and / or 1,4-cyclohexanedimethanol with a carboxylic acid component comprising an even-numbered dicarboxylic acid or an anhydride thereof to obtain an aliphatic polyester. Isocyanate having an isocyanate group and an isocyanate group in the same molecule, and the mixture is allowed to react. Then, with respect to 100 parts by mass of the reaction product, 0.005 to 5 parts by mass of an organic peroxide, preferably 0.005 parts by mass. As described above, an aliphatic polyester is produced by reacting less than 0.01 part by mass (JP-A-7-70296). (D) A method in which an unsaturated isocyanate and a saturated isocyanate are used in combination. A glycol component comprising an even-numbered glycol and / or 1,4-cyclohexanedimethanol is reacted with a carboxylic acid component comprising an even-numbered dicarboxylic acid or an anhydride thereof to obtain an aliphatic polyester. An unsaturated isocyanate and a saturated isocyanate having a saturated group and an isocyanate group in the same molecule are added and reacted, and then 0.005 to 5 parts by mass, preferably 100 parts by mass, of an organic peroxide is added to 100 parts by mass of the reaction product. By reacting at least 0.005 parts by mass and less than 0.01 parts by mass, a high molecular weight aliphatic polyester is produced (JP-A-7-970043). (E) A method of subjecting a lactone resin to radiation treatment. ε-caprolactone, valerolactone, glycolide, homopolymers of lactone monomers such as lactide, and lactone monomers and lactic acid, hydroxylpropionic acid, hydroxylcarboxylic acids such as hydroxybutyric acid, aliphatic diols and aliphatic dicarboxylic acids, and the like. Or a mixture of these homopolymers or copolymers is irradiated to produce a high molecular weight aliphatic polyester (JP-A-2000-15765).

As the biodegradable resin (A), a biodegradable resin (C) other than the above-mentioned aliphatic polyester resin can be blended. Examples of such a biodegradable resin include biodegradable cellulose esters, polypeptides, and polyvinyl alcohol. , Starch, cellulose, paper, pulp, carrageenan, chitin
At least one selected from chitosan, natural linear polyester resin, and a mixture thereof can be preferably applied.

In the present invention, in addition to the biodegradable resin, if necessary, other polymer materials may be mixed as long as the effects of the present invention are not impaired. Also, for the purpose of adjusting molding processability and product properties, lubricants, anti-blocking agents, ultraviolet absorbers, light stabilizers, etc., if necessary,
Plasticizer (phthalic acid ester, etc.), stabilizer (2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, etc.), coloring agent (red mouth yellow Lead, titanium oxide, etc.), filler (calcium carbonate, clay, talc, etc.), antioxidant (alkylphenol, organic phosphite, etc.), ultraviolet absorber (salicylate, benzotriazole, etc.), flame retardant (phosphoric acid) Various known additives such as an ester, antimony oxide, etc.), an antistatic agent, a lubricant, a foaming agent, an antibacterial / antifungal agent and the like can be blended. These blending amounts can be appropriately determined according to the purpose of use. In the present invention, the method of blending the above-mentioned various additives with the aliphatic polyester is not particularly limited, and can be performed by a conventionally known method. For example, mixing and kneading may be performed using a mill roll, a Banbury mixer, a super mixer, a single screw or twin screw extruder, or the like.

The biodegradable resin composition thus kneaded can be shaped by a known molding method such as a melt extrusion method, a calender method, and an injection method. According to the present invention, it is possible to enhance the dispersibility of polytetrafluoroethylene in a biodegradable resin, improve the melting characteristics of the resin, obtain a molded article having good moldability and excellent appearance. .

[0025]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Prior to the examples, the extruder, the molding method, the melting property measuring method, and the evaluation method of the molded article used in the examples will be described. (1) Extruder-1 A biodegradable resin and a modifier were melt-kneaded using a twin-screw extruder having a diameter of 30 mm and L / D = 20 to obtain a biodegradable resin composition pellet. (2) Extruder-2 The above biodegradable resin composition pellets are φ30 mm, L / D
= 25 using a single screw extruder and a thickness of 0.5 by the T-die method.
mm and a width of 150 mm. (3) Melt Flow Rate (MFR) The pellets of the resin composition were measured at a load of 2.16 kg and 190 ° C. according to ASTM D1238. (4) Melt tension (melt tension) The pellets of the resin composition were extruded at a constant extrusion rate (cutting speed of 3.53 / sec) using a descending type flow tester (Rosando Flow Master), and the strands were extruded at a constant speed ( 16
m / min) and the melt tension was measured. L of dice
/ D was 16 mm / 1.0 mmφ. (5) Evaluation of Appearance of Molded Article The surface foreign matter of the obtained sheet-shaped molded article was visually observed, and the following three grades were evaluated. ：: Good appearance without any foreign matter on the surface of the molded product. Δ: Some foreign matter or the like is observed on the surface of the molded body. X: Foreign matters and the like are observed on the surface of the molded product, and the appearance is poor.

Example 1 Polytetrafluoroethylene-containing mixed powder (M-1) (1) Preparation of polydodecyl methacrylate / methyl methacrylate copolymer particle dispersion A mixture of 75 parts of dodecyl methacrylate and 25 parts of methyl methacrylate Add azobisdimethyl valeronitrile to the solution.
One part was dissolved. To this was added a mixture of 2.0 parts of sodium dosylbenzenesulfonate and 300 parts of distilled water,
After stirring at 10,000 rpm for 4 minutes with a homomixer, the mixture was passed through a homogenizer twice at a pressure of 300 kg / cm ² to obtain a stable dodecyl methacrylate / methyl methacrylate preliminary dispersion. This was charged into a separable flask equipped with a stirrer, a condenser, a thermocouple, and a nitrogen inlet, and the inside temperature was stirred at 80 ° C. for 3 hours under a nitrogen gas stream to carry out radical polymerization, thereby co-polymerizing dodecyl methacrylate / methyl methacrylate. A united particle dispersion was obtained. The solid concentration was 25.1%, the particle size distribution showed a single peak, and the weight average particle size was 198 nm.

(2) Preparation of polytetrafluoroethylene-containing mixed powder (M-1) Asahi ICI as a polytetrafluoroethylene particle dispersion
Fluon AD936 manufactured by Fluoropolymer was used. AD
936 has a solids content of 63.0% and contains 5 parts of polyoxyethylene alkylphenyl ether per 100 parts of polytetrafluoroethylene. AD
The particle size distribution of 936 showed a single peak, and the weight average particle size was 290 nm. To 833 parts of AD936, 1167 parts of distilled water was added to obtain a polytetrafluoroethylene particle dispersion having a solid concentration of 26.2%. This is 25
% Polytetrafluoroethylene particles and 1.2% polyoxyethylene nonyl phenyl ether. 160 parts of this polytetrafluoroethylene particle dispersion (40 parts of polytetrafluoroethylene) and 159 of the above prepared dodecyl methacrylate / methyl methacrylate copolymer particle dispersion (40 parts of dodecyl methacrylate / methyl methacrylate copolymer) And 0.4 parts thereof were charged into a separable flask equipped with a stirrer, a condenser, a thermocouple, a nitrogen inlet, and a dropping funnel, and stirred at room temperature for 1 hour under a nitrogen stream. After that, the temperature inside the system was raised to 80 ° C,
0.001 part of iron sulfate, 0.003 part of disodium ethylenediaminetetraacetate, 0.24 part of Rongalit salt, 1 part of distilled water
After adding 0 parts of the mixture, a mixture of 20 parts of methyl methacrylate and 0.1 part of tertiary butyl peroxide was added dropwise over 30 minutes, and after completion of the addition, the internal temperature was maintained at 80 ° C. for 1 hour. The radical polymerization was completed. No solid content was separated through a series of operations, and a uniform particle dispersion was obtained. The solid content concentration of the particle dispersion was 28.5%, the particle size distribution was relatively broad, and the weight average particle size was 248 nm. 349.7 parts of this particle dispersion was treated with calcium chloride 5
The resulting mixture was poured into 600 parts of hot water at 75 ° C., containing 100 parts by mass, separated into solids, filtered and dried to obtain 97 parts of a polytetrafluoroethylene-containing mixed powder (M-1). Dried (M-1)
After being shaped into a strip by a press molding machine at 200 ° C.,
Ultrathin sections obtained with a microtome were observed with a transmission electron microscope without staining. Although polytetrafluoroethylene was observed as a dark part, no aggregate exceeding 10 μm was observed.

Example 2 Polytetrafluoroethylene-containing mixed powder (M-2) The amount of the polytetrafluoroethylene particle dispersion used in Example 1 was changed to 80 parts (polytetrafluoroethylene 20
Parts), the use amount of the dodecyl methacrylate / methyl methacrylate copolymer particle dispersion is 239.1 parts (dodecyl methacrylate / methyl methacrylate copolymer 60).
Parts), and 99 parts of a polytetrafluoroethylene-containing mixed powder (M-2) was obtained in the same manner as in Example 1.
No separation of solids was observed in the particle dispersion before coagulation, and a uniform particle dispersion was obtained. The solid content concentration of the particle dispersion is 26.
At 5%, the particle size distribution was relatively broad and the weight average particle size was 228 nm. Dry (M-2) at 200 ° C
After shaping into a strip shape by a press molding machine in, ultrathin sections with a microtome were observed with a transmission electron microscope without staining. Although polytetrafluoroethylene was observed as a dark part, no aggregate exceeding 10 μm was observed.

Examples 3 to 12, Comparative Examples 1 to 6 As shown in Table 1, lactic acid-based biodegradable resin "Lacti 9400" (manufactured by Shimadzu Corporation, weight average molecular weight of about 1) was used as the biodegradable resin.
40,000) and "Lacti 5000" (manufactured by Shimadzu Corporation, weight-average molecular weight: about 200,000), and mixed with the polytetrafluoroethylene-containing mixed powders M-1, M produced in Examples 1 and 2.
-2 by hand blending, then twin-screw extruder (PC made by Ikegai Co., Ltd.)
Using M-28.5), the mixture was melt-kneaded at a barrel temperature of 200 ° C. and a screw rotation speed of 150 rpm, and shaped into pellets. Table 1 shows the results of measuring various physical properties using the obtained pellets. The melt tension was measured at 175 ° C. For comparison, a biodegradable resin alone was extruded and pelletized under the same conditions as in Example 3, and powdered polytetrafluoroethylene was hand-blended with the biodegradable resin under the same conditions as in Example 3. The extruded and pelletized product was evaluated in the same manner as in Example 3, and the results are shown in Table 1. Asahi IC for powdered polytetrafluoroethylene
Fluon CD123 manufactured by I Fluoropolymers was used. CD123
In the above, primary particles of polytetrafluoroethylene having a particle size of 0.2 to 0.3 μm aggregate to form an aggregate of several hundred μm.

[0030]

[Table 1]

As is clear from Table 1, the resin composition of the present example can improve the melt tension without impairing the appearance of the surface of the molded product as compared with the resin composition of the comparative example. Has been made.

Examples 13 to 22, Comparative Examples 7 to 12 As a biodegradable resin, a polybutylene succinate-based biodegradable resin of 1,4-butanediol and succinic acid "Bionole PBS # 1001" ( "Bionore PBS # 1903" (manufactured by Showa Polymer, linear type, weight average molecular weight about 140,000) (long chain branched type, weight average molecular weight about 330,000 made by Showa Polymer)
After hand-blending this and the polytetrafluoroethylene-containing mixed powders M-1 and M-2 in the proportions shown in Table 2, using a twin-screw extruder (PCM-28.5 manufactured by Ikegai Co., Ltd.),
The mixture was melt-kneaded at a barrel temperature of 180 ° C. and a screw rotation speed of 150 rpm, and was shaped into pellets. Table 2 shows the results of measuring various physical properties using the obtained pellets. The melt tension was measured at 150 ° C. For comparison,
The biodegradable resin alone was extruded and pelletized under the same conditions as in Example 13, and the powdered polytetrafluoroethylene was hand-blended with the biodegradable resin and extruded under the same conditions as in Example 13 to pelletize. Table 2 shows the results of the evaluation of the results in the same manner as in Example 13. As powdery polytetrafluoroethylene, Fluon CD123 manufactured by Asahi ICI Fluoropolymers was used. CD123 is obtained by aggregating polytetrafluoroethylene primary particles having a particle diameter of 0.2 to 0.3 μm to form an aggregate of several hundred μm.

[0033]

[Table 2]

As is clear from Table 2, the resin composition of the present example can improve the melt tension without impairing the appearance of the surface of the molded product as compared with the resin composition of the comparative example. Has been made.

Examples 23 to 32 and Comparative Examples 13 to 18
"Lacty 500" used in Example 8 as a biodegradable resin
"0" or "Bionole 1903" used in Example 18 is a polycaprolactone-based biodegradable resin "Cell Green Praxel H7" (manufactured by Daicel Chemical Industries, Inc., number average molecular weight: about 130,000) and the ratio shown in Table 3. And further mixed with the above polytetrafluoroethylene-containing mixed powder M-1, M-
2 was hand-blended at the ratios shown in Table 2, and the barrel temperature was adjusted to 180 using a twin-screw extruder (PCM-28.5, manufactured by Ikegai).
The mixture was melt-kneaded at 150 ° C. at a screw rotation speed of 150 rpm and shaped into pellets. Table 3 shows the results of measuring various physical properties using the obtained pellets. The melt tension was measured at 175 ° C. when “Lacty 5000” was added, and at 150 ° C. when Bionole “1903” was added. For comparison, the biodegradable resin formulation was extruded and pelletized under the same conditions as in Example 23, and powdered polytetrafluoroethylene was hand-blended with the biodegradable resin under the same conditions as in Example 23. The results obtained by extruding and pelletizing in the same manner as in Examples 23 and 28 are shown in Table 2. As powdery polytetrafluoroethylene, Fluon CD123 manufactured by Asahi ICI Fluoropolymers was used. CD123 is obtained by aggregating polytetrafluoroethylene primary particles having a particle diameter of 0.2 to 0.3 μm to form an aggregate of several hundred μm.

[0036]

[Table 3]

As is clear from Table 3, the resin composition of the present example can improve the melt tension without impairing the appearance of the surface of the molded product, as compared with the resin composition of the comparative example. Has been made.

Examples 33 to 34, Comparative Examples 19 to 20
"Lacty 9400" used in Example 3 was used as the lactic acid-based biodegradable resin, corn starch was used as the biodegradable resin other than the aliphatic polyester-based resin, and the polytetrafluoroethylene-containing mixed powder M-1 was used. Was hand-blended at the ratios shown in Table 4 and then twin-screw extruder (PC made by Ikegai
Using M-28.5), the mixture was melt-kneaded at a barrel temperature of 200 ° C. and a screw rotation speed of 150 rpm, and shaped into pellets. Table 4 shows the results of measuring various physical properties using the obtained pellets. The melt tension was measured at 175 ° C. For comparison, a biodegradable resin alone was used in Example 33,
Table 4 shows the results of extruding and pelletizing under the same conditions as in Example 34 and evaluated in the same manner as in Example 33.

[Examples 35 to 36] "Lacty 9400" used in Example 3 was used as a lactic acid-based biodegradable resin, and the mixed powder M-1 containing polytetrafluoroethylene was 80/20% by mass. To be a twin screw extruder (Ikegai Co., Ltd.)
Using PCM-28.5), the mixture was melt-kneaded at a barrel temperature of 200 ° C. and a screw rotation speed of 150 rpm and shaped into pellets to obtain a polytetrafluoroethylene-containing biodegradable resin master batch MC-1. The polytetrafluoroethylene-containing mixed powder M-1 was fed from a side feeder installed at the center of the extruder barrel. The masterbatch was hand-blended with “Lacty 9400” at a ratio shown in Table 4, and then a sheet-shaped product was obtained by a T-die method using a single screw extruder (manufactured by GM Engineering). Table 4 shows the results of measuring various physical properties using the obtained product. The melt tension was measured at 175 ° C.

[0040]

[Table 4]

As is evident from Table 4, the MFR and the melt tension of the resin composition of this example were both lower than those of the resin composition of the comparative example without impairing the appearance of the surface of the molded article. Can be improved.

[0042]

According to the present invention, by improving the dispersibility of polytetrafluoroethylene in a biodegradable resin, the melting characteristics of the resin can be improved regardless of the molecular weight of the biodegradable resin, A biodegradable resin composition excellent in molding processing can be obtained without impairing the surface appearance. Accordingly, the present invention can easily perform various moldings such as sheet / film molding, foam molding, irregular molding, injection molding, and the like, and can achieve biodegradability of many molded articles. It is very useful for environmental protection.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Osuga 3816 Noto, Noto, Tama-ku, Kawasaki-shi, Kanagawa F-term (reference) 4J002 AB011 AB021 AB041 AB051 AC033 AC063 AD001 AH001 AJ001 BB023 BB113 BB183 BC023 BD152 BE021 BE043 BF013 BF023 BG043 BG103 CF031 CF191

Claims (9)

[Claims] 1. A biodegradable resin modifier comprising a polytetrafluoroethylene-containing mixed powder containing polytetrafluoroethylene particles having an average particle diameter of 10 μm or less and an organic polymer. 2. A polytetrafluoroethylene-containing mixed powder (B) containing polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer, based on 100 parts by mass of the biodegradable resin (A), A biodegradable resin composition which is blended so that the amount of the polytetrafluoroethylene component is 0.01 to 20 parts by mass. 3. The biodegradable resin composition according to claim 2, wherein the main component of the biodegradable resin (A) is an aliphatic polyester resin. 4. The polylactic acid-based biodegradable resin composition according to claim 3, wherein a main component of the aliphatic polyester resin is polylactic acid. 5. The biodegradable resin composition according to claim 3, wherein the aliphatic polyester resin is obtained by a reaction containing aliphatic glycol and aliphatic dicarboxylic acid or a derivative thereof as main components. object. 6. The biodegradable resin composition according to claim 3, wherein a main component of the aliphatic polyester resin is polycaprolactone. 7. The biodegradation according to claim 3, wherein the biodegradable resin (A) contains a biodegradable resin (C) other than the aliphatic polyester resin. Resin composition. 8. The biodegradable resin (C) is a biodegradable cellulose ester, polypeptide, polyvinyl alcohol, starch, cellulose, paper, pulp, carrageenan, chitin / chitosan, natural linear polyester resin, 8. The biodegradable resin composition according to claim 7, wherein the composition is at least one selected from the group consisting of a mixture thereof. 9. A biodegradable resin (A) and a particle diameter of 10 μm.
A master pellet having the following polytetrafluoroethylene-containing mixed powder (B) containing polytetrafluoroethylene particles and an organic polymer is further blended with a biodegradable resin (A), and a polytetrafluoroethylene component Is 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of the biodegradable resin (A).