KR20030011358A - Biodegradable resin composition, film and multifilm for agriculture having controlled biodegradation rate - Google Patents

Abstract

It consists of an aliphatic polyester (A) and a polylactic acid polymer (B) of this invention, and contains 1 weight part or more and less than 20 weight part of polylactic acid polymer (B) with respect to a total of 100 weight part of both. According to the thermoplastic resin composition, a biodegradable film having a controlled biodegradation rate, in particular, a biodegradable agricultural multifilm can be obtained and can be suitably used practically.

Description

Biodegradable resin composition, film and agricultural multi-film with controlled biodegradation rate {BIODEGRADABLE RESIN COMPOSITION, FILM AND MULTIFILM FOR AGRICULTURE HAVING CONTROLLED BIODEGRADATION RATE}

In recent years, environmental problems have been receiving more attention, and accordingly, the sound of development of products having low energy consumption for manufacturing, products that can be recycled as resources, and environment-friendly products, in particular, products having biodegradability, is rising. These products are of great importance in all fields nowadays when environmental issues are attracting attention, and among them, the development of biodegradable products is actively examined by companies and public institutions. At each stage, the tea ceremony ranges.

Biodegradable resins are defined by the Biodegradable Plastics Research Council: `` Plastic plastics have the same physical properties as general-purpose plastics, but once disposed, they are decomposed by the action of microorganisms in the natural environment and finally decomposed into water and carbon dioxide. '' It is said to point. At present, general biodegradable resins include (1) polymers of microbial products such as "Biopole" manufactured by Monsanto Co., Ltd. and (2) derived from natural products such as PCA-based "Cell Green" (cellulose acetate-based) manufactured by Daicel Chemical Industries, Ltd. Polymers, "Bio Nore" manufactured by Showa Polymer Co., Ltd., PHB series "Cell Green" manufactured by Daicel Chemical Industries, Ltd. (blend system of caprolactone resin and condensation type polyester resin), polylactic acid system The chemically synthesized polymers, such as the "Lysia" ["" "made by Nippon Mitsui Chemicals Co., Ltd., are all brand names, etc. are mentioned. Among them, the most developed ones are chemically synthesized polymers, which are still in the development stage, and almost none of the physical properties required for practical use can be cleared while maintaining biodegradability.

In addition, applications in which biodegradable resins are currently being tested include agricultural films, post-bags, food waste bags, and thin molded articles such as bottles, and the like.

For example, Japanese Unexamined Patent Application Publication No. 8-259823 discloses a biodegradable multi-film using a biodegradable polymer material, especially a polymer containing lactic acid units. However, in the multifilm or the like according to this technique, polylactic acid is mainly used, and it is too hard for agricultural multifilm or the like, the biodegradation rate is too slow, and the physical properties are not controlled.

Japanese Laid-Open Patent Publication No. 9-111107 discloses a biodegradable resin film or sheet composed of a polylactic acid polymer and an aliphatic polyester having a glass transition point (Tg) of 0 ° C. or less, in particular, a content of the biodegradable aliphatic polyester is polylactic acid. The film or sheet | seat for thermoforming which is 7-60 weight part with respect to 100 weight part of polymers is disclosed. However, polylactic acid is mainly used by this technique, and biodegradation rate is not controlled as described above.

Japanese Laid-Open Patent Publication No. 9-272794 discloses a film obtained by mixing a polylactic acid polymer with another aliphatic polyester in a weight ratio of 75:25 to 20:80, wherein the tensile modulus is 250 kg / mm 2 or less and the light transmittance is 65%. The above biodegradable film is disclosed. However, the film according to this technique lacks flexibility because the polylactic acid-based polymer is blended in an amount of 20 parts by weight or more with respect to 100 parts by weight, and in particular, when the film is used, it is often used in a field where flexibility is not required. There is.

For example, Japanese Unexamined Patent Application Publication No. 11-222528 discloses a polylactic acid polymer obtained by heating a film in a film containing a polylactic acid polymer and another aliphatic polyester in a weight ratio of 80:20 to 20:80. Disclosed is a biodegradable film having improved fragility, characterized in that the heat-melting calorific value (ΔHm1) is 35 J / g or less. However, the film by this technique also has a problem that the flexibility is insufficient because the whole polylactic acid polymer contains 20 parts by weight or more based on 100 parts by weight.

In particular, the biodegradable agricultural multifilm has been gradually recognized for its usefulness in recent years, and the market has also been put into practical use with it. The performance of the biodegradable agricultural multifilm is required for general agricultural multifilm using general-purpose plastics such as workability when the film is laid on the field (full length), moisturizing or warming after the battlefield, concealability, and growth of crops. It is required to balance the performance and the performance of both the biodegradation rate and the biodegradability peculiar to a biodegradable resin. However, few biodegradable agricultural multifilms that are beginning to be on the market have sufficiently met the performance of both.

Emphasis on film performance as general plastics results in negligible biodegradability, and emphasizing biodegradability results in neglect of general performance. There is still a need for review to fully satisfy the performance of both.

There is a need for a film, in particular a biodegradable agricultural multifilm, in which the rate of biodegradability is controlled and the properties are sufficiently practical.

In order to solve these problems, the present inventors have diligently studied, and as a result, by adding a polylactic acid polymer within a specific range to an aliphatic polyester having excellent film properties but fast biodegradation rate, biodegradability and shape collapse while maintaining film properties It has been found that the speed can be controlled, and the present invention has been completed.

The present invention relates to a biodegradable resin composition, a biodegradable film, and an agricultural multifilm having a controlled biodegradation rate.

That is, the 1st of this invention consists of an aliphatic polyester (A) and a polylactic acid polymer (B), and 1 weight part or more, and 20 parts of polylactic acid polymer (B) with respect to a total of 100 weight part of both. It provides a biodegradable resin composition having a controlled biodegradation rate, characterized in that it contains less than parts by weight.

The second aspect of the present invention is the biodegradability with controlled biodegradation rate according to the first aspect of the present invention, wherein the aliphatic polyester (A) is an aliphatic polyester (A ') having a structure obtained by polycondensation of diol and dicarboxylic acid. It provides a resin composition.

In the third aspect of the present invention, the aliphatic polyester (A ') has a structure obtained by polycondensation of 1,4-butanediol and succinic acid (A (BG-S)), and / or 1,4 An aliphatic polyester (A (BG-S / A)) having a structure obtained by polycondensation of butanediol with succinic acid and adipic acid provides a biodegradable resin composition having a controlled biodegradation rate according to the second aspect of the present invention.

In the fourth aspect of the present invention, the mixing ratio of aliphatic polyester (A (BG-S)) and aliphatic polyester (A (BG-S / A)) is based on 100 parts by weight of the aliphatic polyester (A ( BG-S)) is 90-30 weight part, The biodegradable resin composition of the 3rd controlled biodegradation rate of this invention is provided.

A fifth aspect of the present invention provides the biodegradable resin composition having controlled biodegradation rate according to the first aspect of the present invention, wherein the aliphatic polyester (A) is an aliphatic polyester (A '') having a structure obtained by ring-opening polymerization of lactones. do.

The sixth aspect of the present invention is the biodegradable resin with controlled biodegradation rate according to the fifth aspect of the present invention, wherein the aliphatic polyester (A ″) is a caprolactone polymer (A (CL)) obtained by ring-opening polymerization of ε-caprolactone. To provide a composition.

According to a seventh aspect of the present invention, the biodegradation rate controlled in any one of the first to sixth aspects of the present invention, wherein the aliphatic polyester (A) is a mixture of the aliphatic polyester (A ') and the aliphatic polyester (A' '). It provides a resin composition.

In the eighth aspect of the present invention, the mixing ratio of aliphatic polyester (A ') and aliphatic polyester (A' ') is 90 to 30 parts by weight of aliphatic polyester (A') to 100 parts by weight of the total of both. A biodegradable resin composition having a controlled biodegradation rate according to claim 7 is provided.

In the ninth aspect of the present invention, the mixture ratio of aliphatic polyester (A (BG-S)), aliphatic polyester (A (BG-S / A)) and caprolactone polymer (A (CL)) is the sum of three characters. 90 to 30 parts by weight of aliphatic polyester (A (BG-S)), 5 to 65 parts by weight of (A (BG-S / A)), and caprolactone polymer (A (CL)) based on 100 parts by weight Is 5 to 65 parts by weight the biodegradable resin composition having a controlled biodegradation rate according to the seventh aspect of the present invention.

The tenth aspect of the present invention is directed to any one of the first to ninth aspects of the present invention in which the biodegradation rate is controlled so as to decompose 60% or more in 28 days by the biodegradability test after culturing in the municipal sewage standard sludge prescribed by JIS K6950. Provided are biodegradable resin compositions with controlled biodegradation rates.

The eleventh aspect of the present invention, when the biodegradability test after cultivation in the municipal sewage standard sludge prescribed in JIS K6950, 60% or more is decomposed in 28 days, and when molded into a film, the film according to JIS K7113 Drilled into No. 2 Dumbbell pieces in horticultural soil, bury them under conditions of 28 ° C 99% RH for 60 hours, and conduct tensile tests before and after burial, and elongation in the TD direction is 300% or more before burial. Provided is a biodegradable resin composition having a controlled biodegradation rate according to any one of the first to 10 of the present invention, the biodegradation rate is controlled to be 200% or more.

A twelfth aspect of the present invention is a biodegradable controlled biodegradable rate obtained by inflation molding, T-die extrusion molding, or calender molding the biodegradable resin composition according to any one of 1 to 11 of the present invention. Provide a film.

A thirteenth aspect of the present invention provides a biodegradable agricultural multifilm having a controlled biodegradation rate using the biodegradable film having a controlled biodegradation rate according to the twelfth aspect of the present invention.

(The best form for carrying out the invention)

The detailed description of the present invention is described below.

Although the aliphatic polyester (A) used by this invention is not specifically limited, It is preferable to have thermoplastic at melting | fusing point 60 degreeC or more.

As aliphatic polyester (A), it is obtained by ring-opening polymerization of aliphatic polyester (A ') and lactones having a structure obtained by polycondensation of aliphatic dicarboxylic acid and aliphatic diol or polycondensation of hydroxy carboxylic acid equivalent thereto. Aliphatic polyester (A ") which has a structure is mentioned, The polylactic acid-type polymer (B) mentioned later is not contained.

As the aliphatic polyester (A '), a polyester resin (A (BG-S)) obtained from succinic acid and 1,4-butanediol, and a polyester resin (A (BG-S) obtained from succinic acid, adipic acid and 1,4-butanediol S / A)), polyester resin obtained from succinic acid and ethylene glycol (A (EG-S)), polyester resin obtained from oxalic acid and neopentyl glycol (A (NPG-O)), oxalic acid and 1,4-butanediol Polyester resin (A (BG-O)) obtained from the above, Polyester resin (A (EG-O)) obtained from oxalic acid and ethylene glycol, etc. are mentioned. Preferably, an aliphatic polyester (A (BG-S)) having a structure obtained by polycondensation of 1,4-butanediol and succinic acid, and a structure obtained by polycondensation of 1,4-butanediol with succinic acid and adipic acid The branch is aliphatic polyester (A (BG-S / A)). These may be used alone or in combination.

Examples of the aliphatic polyesters (A ″) include lactone polymers obtained by polymerization of lactones. Examples of the lactones include ε-caprolactone, δ-caprolactone; 4-methylcaprolactone, 3,5,5-trimethyl Various methylated caprolactones such as caprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, β-valerolactone, β Those obtained by ring-opening polymerization of lactones such as -methyl-δ-valerolactone and enanthlactone, those obtained by polycondensation of hydroxy carboxylic acids corresponding to the lactones, and hydroxy carboxylic acids other than lactic acid, for example Examples thereof include glycolic acid, hydroxy pivalic acid, hydroxy capronic acid, hydroxy hexanoic acid and the like, to cyclic esters thereof, and cyclic dimer esters such as, for example, glycolides. Using more than one species, ring opening polymerization or polycondensation What was obtained may be sufficient. As the aliphatic polyester (A "), the caprolactone polymer (A (CL)) obtained by ring-opening-polymerizing (epsilon) -caprolactone can be used preferably. As the caprolactone polymer (A (CL)), in addition to the monocyclic polymer of caprolactone, a monomer unit of caprolactone is contained in an amount of 80% by weight or more, preferably 90% by weight or more, and the rest of the monomer units of other lactones. Phosphorus copolymers are also included.

The preferred weight average molecular weight of these aliphatic polyesters (A) is 40,000 or more, usually 100,000 or more and 250,000 or less, preferably 120,000 or more and 200,000 or less.

In this invention, you may use 2 or more types of said polyester resins (A '), 2 or more types of (A "), or 1 or more types of (A') and (A"), respectively.

As an example of using 2 or more types of said polyester resins (A '), it is a mixture of the said aliphatic polyester (A (BG-S)) and aliphatic polyester (A (BG-S / A)), and the mixing ratio thereof is The aliphatic polyester (A (BG-S)) is more than 0 parts by weight but less than 100 parts by weight, preferably 90 to 30 parts by weight, and particularly preferably 70 to 50 parts by weight based on 100 parts by weight of the total of both.

Moreover, as an example of mixing and using polyester resin (A ') and (A "), with respect to a total of 100 weight part of both, polyester resin (A') is less than 100 weight part and more than 0 weight part, Preferably Is 90 to 30 parts by weight.

As an example which uses each of said (A ') and (A "), and mixes, the mixture of an aliphatic polyester (A (BG-S)) and a caprolactone type polymer (A (CL)) is mentioned, The mixing ratio of the aliphatic polyester (A (BG-S)) is less than 100 parts by weight to more than 0, preferably 90 to 30 parts by weight, more preferably 70 to 100 parts by weight of the total of both. Another example is a mixture of an aliphatic polyester (A (BG-S / A)) and a caprolactone polymer (A (CL)), and the mixing ratio thereof is (A (BG-S)). ) And caprolactone-based polymer (A (CL)).

As an example of mixing and using 2 types of said (A ') and 1 type of (A "), an aliphatic polyester (A (BG-S)), an aliphatic polyester (A (BG-S / A)), and a capro And a mixture of lactone-based polymers (A (CL)), and their mixing ratio is 90 to 30 parts by weight of aliphatic polyester (A (BG-S)), based on 100 parts by weight of the total of three characters. BG-S / A)) is 5-65 parts by weight, and caprolactone-based polymer (A (CL)) is 5-65, and preferably 70-30 parts by weight of aliphatic polyester (A (BG-S)). And (A (BG-S / A)) are 10 to 60 parts by weight, and the caprolactone polymer (A (CL)) is 10 to 60 parts by weight.

As the aliphatic polyester resin (A) used in the present invention, an aliphatic polyester resin containing a urethane bond or a diepoxy compound residue in a molecular chain by reacting with a small amount of a chain extender such as a diisocyanate compound or a diepoxy compound Can be used. The aliphatic polyester resin containing a urethane bond is obtained by high molecular weight of the aliphatic polyester resin, preferably with an aliphatic diisocyanate compound.

Examples of the aliphatic diisocyanate compound include hexamethylene diisocyanate, lysine diisocyanate methyl ester {OCN- (CH ₂ ) ₄ -CH (-NCO) (-COOCH ₃ )}, trimethylhexamethylene diisocyanate, and the like. Methylene diisocyanate is preferred. The preferred weight average molecular weight of the aliphatic polyester resin (A) containing a urethane bond is 40,000 or more, usually 100,000 or more and 250,000 or less, preferably 120,000 or more and 200,000 or less.

The polylactic acid polymer (B) used in the present invention is a polymer containing L-, D- or DL-lactic acid units as a main component. The polylactic acid polymer (B) may be a homopolymer of L- or D-lactic acid, a copolymer of L- and D-lactic acid, or may be a copolymer containing other hydroxy carboxylic acid units as a small amount of copolymerization components. good. As other hydroxy carboxylic acid as a copolymerization component, glycolic acid, hydroxycaproic acid, etc. are mentioned. The copolymerization ratio of lactic acid and other hydroxy carboxylic acids is 100: 0 mol-80:20 mol.

Moreover, these homopolymers or copolymers may contain a small amount of chain extender residues similarly to the aliphatic polyester resin (A).

As a polymerization method of a polylactic acid polymer (B), well-known methods, such as a condensation polymerization method and a ring-opening polymerization method, can be employ | adopted. For example, in the polycondensation method, polylactic acid having an arbitrary composition can be obtained by directly dehydrating polycondensation of L-lactic acid or D-lactic acid or a mixture thereof. In addition, in the ring-opening polymerization method (lactide method), a polylactic acid polymer (B) can be obtained by using a catalyst selected from a lactide, which is a cyclic dimer of lactic acid, if necessary using a polymerization regulator or the like. As a preferable range of the weight average molecular weight of the polylactic acid polymer (B) used in this invention, it is 60,000-70,000, More preferably, it is 80,000-400,000, Especially preferably, it is 100,000-300,000. If the molecular weight is too small, practical properties such as mechanical properties and heat resistance are hardly expressed. If the molecular weight is too large, the melt viscosity is too high and molding processability is poor.

The mixing ratio of the aliphatic polyester resin (A) and the polylactic acid polymer (B) depends on the molecular weight and melt flow characteristics of each resin, and also on the required biodegradation rate, but the total of (A) and (B) is 100 It is essential that (B) is 1 weight part or more and less than 20 weight part with respect to a weight part, Preferably it is 2-15 weight part, Especially preferably, it is the range of 5-10 weight part. At this time, when (B) is less than 1 part by weight, there is no effect of delaying the biodegradation rate. On the contrary, at 20 parts by weight or more, the physical properties of the agricultural multifilm, in particular, the flexibility is insufficient.

Other biodegradable resins may be added to the biodegradable agricultural multifilm having controlled biodegradation rate of the present invention as needed.

As other biodegradable resins, synthetic and / or natural polymers are used.

Examples of the synthetic polymers include polyamides, polyamide esters, biodegradable cellulose esters, polypeptides, polyvinyl alcohols, or mixtures thereof.

As biodegradable cellulose ester, Organic acid ester, such as cellulose acetate, cellulose butyrate, and cellulose propionate; Inorganic acid esters such as cellulose nitrate, cellulose sulfate and cellulose phosphate; And mixed esters such as cellulose acetate butyrate, cellulose acetate phthalate, cellulose nitrate acetate and the like. These cellulose esters can be used individually or in mixture of 2 or more types. Of these cellulose esters, organic acid esters, in particular cellulose acetate, are preferred.

Moreover, as a polypeptide, polyamino acids, such as polymethyl glutamic acid, polyamide ester, etc. can be illustrated.

Examples of the polyamide esters include resins synthesized from ε-caprolactone and ε-caprolactam.

As the synthetic polymer, a weight average molecular weight of 40,000 or more, usually 100,000 or more and 250,000 or less, preferably 120,000 or more and 200,000 or less can be used in terms of standard polystyrene by GPC.

Examples of the natural polymer include starch, cellulose, paper, pulp, cotton, hemp, wool, silk, leather, carrageenan, chitin chitosan, natural linear polyester resins, or mixtures thereof.

Examples of the starch include raw starch, processed starch and mixtures thereof.

Examples of raw starch include corn starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, rice starch, soybean starch, boiled starch, bracken starch, soft starch, dried starch and the like. As a physical modified starch ( Starch, fractionated amylose, wet heat-treated starch, etc. Starch derivatives (esterified starch, etherified starch, cationic starch, crosslinked starch, etc.);

Among the above-mentioned esterified starch, acetic acid esterified starch, succinic acid esterified starch, nitrate esterified starch, phosphate esterified starch, urea phosphate esterified starch, xanthogenic esterified starch, acetoacetic acid esterified starch, etc .; As etherified starch, allyl ether starch, methyl ether starch, carboxymethyl ether starch, hydroxyethyl ether starch, hydroxypropyl ether starch, etc .; Examples of the cationic starch include reactants of starch and 2-diethylaminoethyl chloride, reactants of starch and 2,3-epoxypropyl trimethylammonium chloride, and the like; Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, acrolein crosslinked starch and the like.

The resin additive can be added to the biodegradable resin composition whose biodegradation rate of this invention was controlled as needed.

Resin additives include plasticizers, thermal stabilizers, lubricants, antiblocking agents, nucleating agents, photodegradants, biodegradation accelerators, antioxidants, light (ultraviolet) stabilizers, antistatic agents, flame retardants, oil repellents, antibacterial agents, deodorants, fillers, colorants Or mixtures thereof.

Examples of the plasticizer include aliphatic dibasic acid esters, phthalic acid esters, hydroxy polyhydric carboxylic acid esters, polyester plasticizers, fatty acid esters, epoxy plasticizers, or mixtures thereof. Specifically, phthalic acid esters, such as di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), and diisodecyl phthalate (DIDP), adipic acid- di-2-ethylhexyl (DOA), and adipe Hydroxy polyvalents such as adipic acid esters such as acid diisodecyl (DIDA), azelaic acid esters such as azelaic acid-di-2-ethylhexyl (DOZ), acetyl tri-2-ethylhexyl, acetyl tributyl citrate Polyester plasticizers, such as a carboxylic acid ester and a polypropylene glycol adipic acid ester, These are used by 1 type, or 2 or more types of mixtures.

Although the addition amount of these plasticizers changes with uses, generally 3-30 weight part, Preferably it is 5-15 weight part with respect to a total of 100 weight part of aliphatic polyester (A) and a polylactic acid-type polymer (B). to be. If it is less than 3 parts by weight, the breaking elongation and impact strength will be lowered. If it exceeds 30 parts by weight, the breaking strength and impact strength may be lowered.

As the heat stabilizer used in the present invention, there are aliphatic carboxylates. As aliphatic carboxylic acid, aliphatic hydroxy carboxylic acid is especially preferable. As aliphatic hydroxy carboxylic acid, what exists in nature, such as lactic acid and hydroxy butyric acid, is preferable.

As a salt, salts, such as sodium, calcium, aluminum, barium, magnesium, manganese, iron, zinc, lead, silver, copper, are mentioned. These can be used as 1 type, or 2 or more types of mixtures.

As addition amount, it is the range of 0.5-10 weight part with respect to a total of 100 weight part of aliphatic polyester (A) and a polylactic acid polymer (B). When the thermal stabilizer is used in the above range, the impact strength (Izod impact value) is improved, and the difference in breaking elongation, breaking strength and impact strength is reduced.

As a lubricant used by this invention, what is generally used as an internal lubricant and an external lubricant can be used. For example, fatty acid esters, hydrocarbon resins, paraffins, higher fatty acids, oxy fatty acids, fatty acid amides, alkylenebis fatty acid amides, aliphatic ketones, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, aliphatic alcohols, polyhydric alcohols , Polyglycol, polyglycerol, metal soap, modified silicone or a mixture thereof. Preferably, fatty acid ester, hydrocarbon resin, etc. are mentioned.

When selecting a lubricant, it is necessary to select the lubricant below the melting point according to the melting point of the lactone resin or other biodegradable resins. For example, in consideration of the melting point of the aliphatic polyester resin, the fatty acid amide of 160 ° C. or less is selected as the fatty acid amide.

The compounding quantity adds 0.05-5 weight part of lubricants with respect to a total of 100 weight part of aliphatic polyester (A) and a polylactic acid polymer (B). If it is less than 0.05 weight part, an effect will not be enough, and if it exceeds 5 weight part, it will not be wound up to a roll and a physical property will also fall.

As the lubricant, ethylene bis stearic acid amide, stearic acid amide, oleic acid amide, and erucic acid amide, which have high safety and are registered with the FDA (Food and Drug Administration), are preferable from the viewpoint of preventing environmental pollution.

As said photodegradation agent, For example, benzophenone and its derivatives, such as benzoin, benzoin alkyl ether, benzophenone, 4, 4-bis (dimethylamino) benzophenone; Acetophenone, , Acetophenones and derivatives thereof such as diethoxyacetophenone; Quinones; Thioxanthones; Photoexcitation materials, such as phthalocyanine, an anatase type titanium oxide, an ethylene-carbon monoxide copolymer, the sensitizer of an aromatic ketone, and a metal salt, etc. are illustrated. These photodegradants can be used together 1 type or 2 types or more.

Examples of the biodegradation accelerator include oxo acid (for example, oxo acid having about 2 to 6 carbon atoms such as glycolic acid, lactic acid, citric acid, tartaric acid and malic acid), saturated dicarboxylic acid (for example, oxalic acid, Organic acids such as lower saturated dicarboxylic acids having about 2 to 6 carbon atoms such as malonic acid, succinic acid, succinic anhydride and glutaric acid; Lower alkyl esters of these organic acids and alcohols having 1 to 4 carbon atoms are included. Preferred biodegradation accelerators include organic acids having about 2 to 6 carbon atoms, such as citric acid, tartaric acid, and malic acid, and coconut shell activated carbon. These biodegradation promoters can be used together 1 type or 2 types or more.

Examples of the light (ultraviolet) stabilizer include poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl} {(2,2, 6,6-tetramethyl-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-piperidyl) imino}], poly [{6- (1,1,3- Trimethylpentyl) imino-1,3,5-triazine-2,4-diyl} {(N-methyl-2,2,6,6-tetramethyl-piperidyl) imino} octamethylene {(N -Methyl-2,2,6,6-tetramethyl-piperidyl) imino}], 2,2,6,6-tetramethylpiperidinyl-4-benzoate, bis- (2,2,6 , 6-tetramethyl-4-piperidinyl) sebacate, 1,3,8-triaza, 7,7,9,9-tetramethyl-3-n-octyl-spiro [4,5] decane-2 , 4-dione, 1,2,3,4-tetra (4-carbonyloxy-2,2,6,6-tetramethylpiperidine) -butane, tri- (4-acetoxy-2,2, Hindered amine light stabilizers such as 6,6-tetramethylpiperidine) -amine (HALS), 2- (2H-benzotriazol-2-yl) -P-cresol, 2- (2H-benzotriazole -2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazole-2 Benzotriazoles such as -yl-4,6-di-tert-butylphenol and 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol A ultraviolet absorber, a triazine ultraviolet absorber, a benzophenone ultraviolet absorber, and a benzoate ultraviolet absorber are mentioned preferably. The compounding quantity of these stabilizers is 100 in total of an aliphatic polyester (A) and a polylactic acid polymer (B). It is 0.01-1.10 weight part with respect to a weight part, Preferably it is the range of 0.05-0.5 weight part.

Examples of the fillers (including extenders) include various fillers such as calcium carbonate, mica, calcium silicate, talc, fine powder silica (anhydrous), white carbon (water), asbestos, clay (calcined), elvan, various oxidations. Inorganic additives (also referred to as inorganic fillers) such as titanium and glass fibers, and organic additives (also referred to as organic fillers) such as particles of natural materials.

Addition of a filler further improves biodegradability and increases melt strength (viscosity), thereby preventing drawdown during melt molding and improving moldability such as vacuum molding, blow molding and inflation molding.

As for the addition amount of a filler, the weight ratio of filler / [the sum total of an aliphatic polyester (A) and a polylactic acid polymer (B)] is 5-50 / 95-50, Preferably it is 10-45 / 90-55, More preferably, Is 20-40 / 80-60, Especially preferably, it is 25-35 / 75-65.

When the amount of the filler is excessive, the powder is oozed out of the resin, and when the amount is too small, drawdown, necking, nonuniform thickness, and generation of unfilled parts of the corner may be remarkable.

The fine powder silica as the inorganic additive may be a silica produced by a wet method or a silica produced by high temperature hydrolysis in an oxyhydrogen flame of silicon tetrachloride, but a particle diameter of 50 nm or less is preferable.

Examples of the organic additives include fine powder particles made of paper having a diameter of 50 microns or less. The addition amount of an organic additive is the same as that of an inorganic additive.

Examples of the extender include wood powder and glass balloons. The amount of the extender added is the same as in the case of the inorganic additive.

As a coloring agent, various well-known inorganic and organic coloring agents, such as carbon black, etc. are mentioned.

Moreover, in the range which does not impair the effect of this invention, you may add said other biodegradable resin, Moreover, in order to adjust molding processability and the physical property of a film and a sheet, a plasticizer, a fluidity improver, a lubricant, It is also possible to add a reinforcing agent, an inorganic insulating agent, a fluorescent agent and the like.

In the biodegradable resin composition provided in the present invention, the decomposition rate after culturing in the municipal sewage standard sludge prescribed by JIS K6950 is 60%, preferably 80% or more. Moreover, the biodegradable film provided by this invention can be used as a replacement of conventional polyethylene and other polyolefin.

Examples of methods for evaluating biodegradability of samples include methods of using activated sludge according to JIS K6950, embedding in soil, dipping in seawater and rivers, and evaluation on the post. It is performed according to JIS K6950 which is considered to have a correlation with degradability.

In the present invention, "controlled biodegradation rate" means "controlled biodegradability and shape decay rate", and "physically necessary physical properties (for example, mechanical properties such as tensile strength, tensile elongation, and tensile modulus) as a product. Is kept sufficiently during the period of use, and after disposal, the film is JIS K7113 when decomposed into a film at 60% or more, preferably 80% or more in 28 days by the biodegradability test. Drilled into No. 2 dumbbell piece in horticultural soil, burying for 60 hours under conditions of 28 ° C 99% RH, performing tensile test before and after laying, and elongation in the TD direction is 300% or more before laying. Preferably at least 400%, more preferably at least 500%, after embedding at least 200%, preferably at least 300%, more preferably at least 400%.

As the kneading method of aliphatic polyester resin, lactone resin, polylactic acid resin, and other additives, a general method can be preferably used. Specifically, raw material resin pellets, powders, and fine pieces of solid are Henschel mixer. Dry mixing with a ribbon mixer, and supplying it to well-known melt mixers, such as a single screw and a twin screw extruder, a Bumberry mixer, a kneader, and a mixing roll, and melt-kneading it.

After melt kneading, it is molded into a biodegradable film as it is, or preferably in pellet form. There is no restriction | limiting in particular as a shaping | molding method, A conventional method can be used. Specifically, inflation molding, T-die extrusion molding, calendar molding, etc. may be mentioned. Preferably inflation molding and T-die extrusion molding.

<Example 1-6, Comparative Example 1-3>

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these.

The raw material used in the Example and the symbol used in following Table 1 are shown below.

# 1001: Bionolle # 1001 [aliphatic polyester (A) of aliphatic dicarboxylic acid-aliphatic diol system, manufactured by Showa Polymer Co., Ltd.]

# 3001: Bionolle # 3001 [aliphatic polyester of aliphatic dicarboxylic acid-aliphatic diol type (A (BG-S / A)), Showa Polymer Co., Ltd. product]]

PH7: Cell green PH7 [caprolactone type polymer (A (CL)), Daicel Chemical Industry Co., Ltd. product]

Lactyl 9400: [polylactic acid polymer (B), manufactured by Shimadzu Corporation]

[Compound]

The resin blended by the prescription shown in Table 1 was compounded and pelletized on the following extrusion conditions using the twin screw extruder. The water support fee used previously dried (50 degreeC x 10 hours or more). In addition, the tumbler was used for each blend.

<Extrusion Condition>

C1 (under hopper): 100 ° C, C2: 180 ° C, C3: 200 ° C, C4: 200 ° C, C5: 200 ° C, C6: 210 ° C, C7: 210 ° C, AD (die front): 210 ° C, D ( Die): 200 ℃

The numbers 1 to 7 of C increase from the bottom of the hopper of C1 toward the die direction. Moreover, the numbering of a film forming process is also the same.

The resin supplied from the hopper is extruded from C1 (under the hopper) to D (die) and then cut by a pelletizer.

[Filming]

Using the pellet obtained above, the film was obtained on the following inflation molding conditions.

<Inflation Molding Conditions>

C1 (under hopper): 100 ° C, C2: 150 ° C, C3: 160 ° C, C4: 160 ° C, C5: 160 ° C, C6: 160 ° C, AD (die front): 160 ° C, D (die) 1: 150 ℃, D (die) 2: 150 ℃

The pellet supplied from the hopper is extruded from C1 (under the hopper) to D (die), extruded upward from D (die), and expands in a cylindrical shape by air pressure to form a film.

Film taking rate: 17.0 ~ 22.Om / min

Lip Width: 2.Omm

Film width: 1350mm

Film thickness: 20㎛

Thus, various evaluation shown below was performed using the obtained resin pellet and the film molded object, and the result was shown in Table 2.

Hydrothermality

Putting the cutting part in the polyethylene film (inflation molding) which is widely used as a general-purpose film is based on the sense of tearing by hand (out of 10 points), and the feeling when the respective films obtained above are torn by hand. It evaluated on a 10 point scale.

As a criterion at this time, the overall tearability was sensually evaluated in addition to simple strength, such as resistance transmitted to the hand when it was torn by hand, the method of tearing (with or without linearity), and the waveform of the torn surface.

The evaluation criteria of sensory evaluation are as follows.

(Double-circle): A torn surface is wavy and also torn at an angle, and a tear resistance is large.

: Torn surface is straight and wave shape is small, but tear resistance is large.

X: The torn surface is straight and the tear resistance is small.

××: Tear resistance is smaller than X, and tearing is easy to propagate.

[Tear strength]

Sample: Each film obtained above was cut | disconnected to width 25mm and length (MD direction) 100mm, and what cut | disconnected 30 mm of cuts in the longitudinal direction from the middle at one end of the width was used.

The sample was controlled for 24 hours in a constant temperature and humidity room at 23 ° C. × 50% RH, and used for measurement.

<Tear strength measurement condition>

Sample length (distance between chucks): 30 mm

A device: OLIENTEC company, brand name RTA-500

Load cell: 5kgf, 20%

Crosshead Speed: 500mm / min

Number of tests: n = 3, and the result was shown by the average value.

The evaluation criteria of sensory evaluation are as follows.

(Double-circle): Tear strength is strong, it is torn at an angle, and the torn surface is wavy.

: Tear strength is strong, torn surface is straight, and torn surface is wavy.

X: The tear strength is weak and the torn surface is straight.

××: The tear strength is very weak, the torn surface is straight, and there is almost no wave form of the torn surface.

[Tensile Test]

The tension test was done using the thing which perforated each film obtained above with the No. 2 dumbbell piece based on JISK7113. In addition, punching of the film was performed about MD and TD directions.

Samples were subjected to humidity control for 24 hours in a constant temperature and humidity room at 23 ° C. × 50% RH and used for measurement. In addition, measurement conditions are as follows.

Tensile test measurement conditions

Sample length (distance between chucks): 80mm

Equipment used: OLIENTEC company, trade name RTA-500

Load cell: 10kgf, 40%

Crosshead Speed: 500mm / min

Number of tests: n = 3, and the result was shown by the average value.

[Biodegradable]

Biodegradability was evaluated according to the simple degradability test (JIS K6950) using activated sludge.

Himejishi standard activity sludge was used to measure biodegradability (% by weight) after 28 days of testing. In addition, the biodegradable values obtained in the above test were 60% or less, and 60% or more. , 80% or more are indicated by?.

[Shape decay rate]

In accordance with JIS K7113, each film obtained above was punched into No. 2 dumbbell pieces in horticultural soils (manufactured by Angel Co., Ltd., soil of flowers and vegetables (home cultivation soil for home horticulture)), and was subjected to 28 ° C 99% RH. The film was buried under conditions of 60 hours, and the above tensile test was performed on the film before and after the embedding, and the tensile elongation at break in the TD direction was compared. In addition, the film after the said embedding is also called the film after a decomposition rate evaluation.

Comparative Example 3 is a system in which 50% by weight of polylactic acid-based polymer (B) is added, but it is because the polylactic acid lacks flexibility, and both the molding processability and the film initial physical properties are not suitable for the thin film. . In addition, with respect to the biodegradability, the addition rate of the polylactic acid-based polymer (B) was 50% by weight, which resulted in a very low decomposition rate, which resulted in unsuitable use for agricultural multi-films and the like used in a short time.

In Comparative Examples 1 and 2, the addition amount of the polylactic acid-based polymer (B) was reduced to 20% by weight, but the film performance was not sufficient for breaking elongation in the MD direction, particularly for elongation in the TD direction. It was not enough for the use of a multi film. The tensile elongation retention in the TD direction after the decomposition rate evaluation was high, but this was not practical because the initial elongation was insufficient.

On the other hand, Examples 1 and 2 are the systems which add 5 and 10 weight part of addition amounts of a polylactic acid-type polymer (B). There was no problem in molding processability, and the elongation at break after film molding, particularly in the TD direction, was greatly improved. When the elongation at break in the TD direction rises to more than 300%, practicality emerges. The elongation at break in the TD direction after the decomposition rate evaluation of this sample was also well maintained.

Examples 4, 5, and 6 are polyester components other than the polylactic acid polymer (B), in which flexible polyester is blended (that is, mixed with a plurality of aliphatic polyesters (A) in a specific range), As a result, the TD fracture elongation was remarkably improved, and the tear strength was also remarkably improved. The obtained film is made into sufficient numerical value for practical properties, such as an agricultural multi-film. The elongation at break in the TD direction was also well maintained after the decomposition rate evaluation.

From the above, it has been confirmed that a biodegradable resin composition having a controlled biodegradation rate, a biodegradable rate controlled, and a biodegradable film having practical properties, in particular, a biodegradable agricultural multifilm can be provided.

Claims (13)

It consists of an aliphatic polyester (A) and a polylactic acid polymer (B), and contains 1 weight part or more and less than 20 weight part of polylactic acid polymers (B) with respect to a total of 100 weight part of both. Biodegradable resin composition with controlled biodegradation rate. The biodegradable resin composition with controlled biodegradation rate according to claim 1, wherein the aliphatic polyester (A) is an aliphatic polyester (A ') having a structure obtained by polycondensation of diol and dicarboxylic acid. The aliphatic polyester (A ') according to claim 2, wherein the aliphatic polyester (A') has a structure obtained by polycondensation of 1,4-butanediol and succinic acid (A (BG-S)), and / or 1,4- A biodegradable resin composition having controlled biodegradation rate, characterized in that it is an aliphatic polyester (A (BG-S / A)) having a structure obtained by polycondensation of butanediol with succinic acid and adipic acid. 4. The mixing ratio of aliphatic polyester (A (BG-S)) and aliphatic polyester (A (BG-S / A)) is based on the total of 100 parts by weight of aliphatic polyester (A (BG). -S)) biodegradable resin composition with controlled biodegradation rate, characterized in that 90 to 30 parts by weight. The biodegradable resin composition with controlled biodegradation rate according to claim 1, wherein the aliphatic polyester (A) is an aliphatic polyester (A ") having a structure obtained by ring-opening polymerization of lactones. The biodegradable resin composition having a controlled biodegradation rate according to claim 5, wherein the aliphatic polyester (A ") is a caprolactone polymer (A (CL)) obtained by ring-opening polymerization of ε-caprolactone. The biodegradable controlled biodegradability according to any one of claims 1 to 6, wherein the aliphatic polyester (A) is a mixture of aliphatic polyester (A ') and aliphatic polyester (A "). Resin composition. 8. A mixture ratio of aliphatic polyester (A ') and aliphatic polyester (A ") is characterized in that the aliphatic polyester (A') is 90 to 30 parts by weight based on 100 parts by weight in total. Biodegradable resin composition with controlled biodegradation rate. The mixing ratio of aliphatic polyester (A (BG-S)), aliphatic polyester (A (BG-S / A)) and caprolactone polymer (A (CL)) is 100 in total. 90 to 30 parts by weight of aliphatic polyester (A (BG-S)), 5 to 65 parts by weight of (A (BG-S / A)), and caprolactone polymer (A (CL)) The biodegradable resin composition with controlled biodegradation rate, characterized in that 5 to 65 parts by weight. The biodegradation rate according to any one of claims 1 to 9, wherein the biodegradation rate is controlled so as to decompose 60% or more in 28 days by the biodegradability test after cultivation in the municipal sewage sludge defined in JIS K6950. Biodegradable resin composition with controlled biodegradation rate. The biodegradability test after cultivation in municipal sewage sludge as defined in JIS K6950, which decomposes at least 60% in 28 days and is molded into a film according to any one of claims 1 to 10. , The film was drilled by the No. 2 dumbbell piece according to JIS K7113 in horticultural soil, and was buried for 60 hours under conditions of 28 ° C 99% RH, and subjected to a tensile test before and after buried, and the elongation in the TD direction before the buried The biodegradation rate controlled biodegradable resin composition, characterized in that the biodegradation rate is controlled to be at least 300%, 200% or more after embedding. The biodegradable film having a controlled biodegradation rate, obtained by inflation molding, T-die extrusion molding, or calender molding of the biodegradable resin composition according to any one of claims 1 to 11. A biodegradable agricultural multifilm having a controlled biodegradation rate, wherein the biodegradable film having a controlled biodegradation rate according to claim 12 is used.