JP2000256471A - Biodegradable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable film improved in continuous moldability, strengths, and a rate of biodegradation by molding a composition comprising an aliphatic polyester resin and a linear polycaprolactone. SOLUTION: The resin composition is obtained by mixing 30-95 wt.% aliphatic polyester resin having a melt flow rate of 1-9 g/10 min, desirably, 2-7 g/10 min, a melt tension of at least 2 g, desirably, 5-10 g, a melting point of 100 deg.C or higher, and a number-average molecular weight of 1,000-500,000, desirably, 50,000 or above with 70-5 wt.% linear polycaprolactone having a melt tension of 2 g or above, desirably, 5-10 g, a melt flow rate of 1-9 g/10 min, desirably, 2-7 g/10 min, a melting point of 60 deg.C or above, and a number-average molecular weight of 1,000-1,000,000, desirably, 5,000-500,000. The resin composition is melt- kneaded and molded into a film for 1 hr or longer, desirably, 3 hr or longer at a production rate of 10-30 m/min, desirably, 15-20 m/min to obtain a biodegradable film having a thickness of 5-25 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin biodegradable film, and more particularly, to a thin biodegradable film comprising a composition of an aliphatic polyester resin having a specific melt flow rate and melt tension and polycaprolactone, The present invention relates to a thin biodegradable film having a thickness of 5 to 25 μm.

[0002]

2. Description of the Related Art Conventionally used thin films are:
Polyolefin resins such as polyethylene and polypropylene, and resins made of polyvinyl chloride and polyvinylidene chloride are mainly used. However, films made from such resins increase the amount of garbage when discarded, and when buried, they remain semi-permanently underground, and when discarded, damage the landscape or reduce dioxin emissions. It has caused environmental problems such as the occurrence. Therefore, in order to solve these problems, biodegradable resins have recently attracted attention. Here, biodegradable resin, when used as a material, has almost the same physical properties as general-purpose plastics, but after disposal, in the natural environment such as on soil, in soil, in compost, in activated sludge, in water, etc. Is a macromolecule that is rapidly degraded and assimilated biochemically by microorganisms such as bacteria and fungi, and is finely decomposed into carbon dioxide and water.

Conventionally, as a biodegradable resin, starch, EVOH (ethylene-vinyl alcohol copolymer) resin, EVOH resin, besides a specific polyester-based biodegradable resin in order to satisfy the above requirements. Blend-based resin compositions such as aliphatic polyester-based resins and aliphatic polyester-based resin-polyolefin-based resins are known. These resins or resin compositions are formed into various shapes such as films and used for practical use. However, other properties such as physical properties required for the film used in the present invention and biochemical degradability required after disposal are required. , Moldability required during the production of the film,
In particular, there has not yet been proposed an excellent film which is balanced in that there is no film breakage during continuous production.

Japanese Patent Application Laid-Open No. 8-188706 discloses that a biodegradable resin, polycaprolactone (hereinafter sometimes abbreviated as PCL), is contained in an amount of 80 to 100% by weight and a biodegradable linear product produced by living organisms. Polyester resin 20 ~
0 to 100% by weight of a mixture with 0.3% by weight of a lubricant
Although a biodegradable plastic film obtained by molding a composition comprising 0.8 parts by weight is disclosed, there is a problem in mechanical strength at the time of film formation, and a thin film is continuously formed. Not only is it difficult to mass-produce, but even if the film bag is put into a composting device together with garbage, the biochemical decomposition of the bag takes 100 days, so the decomposition rate cannot be said to be sufficiently fast.

[0005] On the other hand, polycaprolactone is a crystalline resin, has a relatively low melting point of 60 ° C, has insufficient heat resistance and tensile strength, and is limited in application to packaging materials such as films.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin biodegradable film having a good continuous formability, excellent strength, a high biodegradation rate, and a thickness of 5 to 25 μm. is there.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that as a raw material, a composition of an aliphatic polyester resin having a specific range of melt flow rate and melt tension and polycaprolactone is used. By
The inventors have found that such a problem of the thin film can be solved, and have completed the present invention.

That is, according to the first aspect of the present invention, the aliphatic polyester resin comprises a composition of an aliphatic polyester resin and polycaprolactone, and the aliphatic polyester resin has a melt tension of 2 g.
A biodegradable film having a melt flow rate of 1 to 9 g / 10 min, the polycaprolactone being a linear polycaprolactone, and a film thickness of 5 to 25 μm. According to a second aspect of the present invention, the composition comprises a composition of an aliphatic polyester resin and polycaprolactone, and the polycaprolactone has a melt tension of 2 g.
A biodegradable film having a melt flow rate of 1 to 9 g / 10 min, the aliphatic polyester resin being a linear aliphatic polyester resin and a film thickness of 5 to 25 μm is provided. According to a third aspect of the present invention, a film comprising a composition of an aliphatic polyester resin and polycaprolactone, wherein the composition has a melt tension of 2 g or more, a melt flow rate of 1 to 9 g / 10 minutes, and a film A biodegradable film having a thickness of 5 to 25 μm is provided. According to the fourth aspect of the present invention, the aliphatic polyester resin comprises an aliphatic dicarboxylic acid, an aliphatic diol, and a trifunctional or higher aliphatic polycarboxylic acid and / or
Alternatively, the present invention provides the first or third biodegradable film of the present invention, which is a polyester resin containing a structural unit of an aliphatic polyol. According to the fifth aspect of the present invention, the aliphatic polyester resin uses succinic acid and / or adipic acid as a dicarboxylic acid component and a polyester containing a structural unit of ethylene glycol and / or 1,4-butanediol as a diol component. A biodegradable film according to any one of the first to fourth aspects of the present invention, which is a resin. According to a sixth aspect of the present invention, the aliphatic polyester resin is modified with a diisocyanate and / or a polyisocyanate having three or more functional groups. A biodegradable film as described is provided. According to a seventh aspect of the present invention, the diisocyanate and / or trifunctional or higher polyisocyanate is hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, hydrogenated triphenylmethane. A sixth biodegradable film of the present invention is provided, which is a triisocyanate or a mixture thereof. According to an eighth aspect of the present invention, the polycaprolactone is a crosslinked polycaprolactone, or is obtained by polymerization using a polyol having three or more functional groups as an initiator. Are provided. According to a ninth aspect of the present invention, the biodegradable film according to any one of the first to third aspects of the present invention, wherein the content of polycaprolactone to the aliphatic polyester resin is 70 to 30% by weight to 5 to 95% by weight. Is provided.
According to the tenth aspect of the present invention, a plasticizer, a heat stabilizer, a lubricant, an anti-blocking agent, a nucleating agent, a photolytic agent, a biodegradation accelerator, an antioxidant, are added to the composition of the aliphatic polyester resin and polycaprolactone. UV stabilizers, antistatic agents, conductive agents,
A biodegradable film according to any one of the first to third aspects of the present invention, which comprises a flame retardant, a dropping agent, an antibacterial agent, a deodorant, a filler, a colorant, or a mixture thereof. Eleventh of the present invention
According to the present invention, there is provided the biodegradable film according to any one of the first to third aspects of the present invention, which is uniaxially or biaxially stretched.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the melt tension (MT) is a value (unit: g) measured under the conditions of a cylinder temperature of 150 ° C., a cylinder speed of 1 mm / min, a take-up speed of 10 m / min, and a distance between a capillary and a load cell of 50 cm. And the melt flow rate (MFR) is 190 ° C.
Value measured under the condition of a load of 2,160 g (unit: g / 10
Minute). The present invention is a biodegradable film obtained by molding a composition of an aliphatic polyester resin and polycaprolactone and having a film thickness of 5 to 25 μm, wherein the aliphatic polyester resin, the polycaprolactone, or the It is characterized in that any one of the compositions has an MT of 2 g or more and an MFR of 1 to 9 g / 10 min.

Hereinafter, the components of the resin composition of the present invention will be described. Aliphatic polyester resin (I) The aliphatic polyester resin (I) has a MT of 2 g or more, preferably 5 to 10 g, particularly preferably one that does not break (bag break when formed into a bag), and has an MFR of 1 to 9
g / 10 minutes, preferably 2 to 7 g / 10 minutes, particularly preferably 2 to 5 g / 10 minutes. Further, those having a melting point of 100 ° C. or more and having thermoplasticity are preferred. The aliphatic polyester resin (I) comprises an aliphatic dicarboxylic acid (a), an aliphatic diol (b), a trifunctional or higher aliphatic polycarboxylic acid (c) and / or a trifunctional or higher aliphatic polyol (d).
Polyester (I ') consisting of the following or a linear aliphatic polyester (i) consisting of an aliphatic dicarboxylic acid (a) and an aliphatic diol (b) is modified with a diisocyanate and / or a trifunctional or higher polyisocyanate Aliphatic polyester (I ") obtained by the above or these (I ')
And (I ").

The aliphatic polyester resin (I ') includes a linear or branched aliphatic dicarboxylic acid (a) having 1 to 10 carbon atoms, a linear or branched aliphatic diol (b) having 1 to 10 carbon atoms, and Trifunctional or higher functional aliphatic polycarboxylic acid (c) and / or trifunctional or higher functional aliphatic polyol (d)
With polyester. Here, the trifunctional or higher aliphatic polycarboxylic acid (c) is a linear or branched one having 1 to 10 carbon atoms, and the trifunctional or higher aliphatic polyol (d) is a linear or branched linear polyol having 1 to 10 carbon atoms. Or a branch. The ratio of the aliphatic dicarboxylic acid (a) to the aliphatic diol (b) in the aliphatic polyester resin (I ′) is such that aliphatic dicarboxylic acid (a): aliphatic diol (b) = 30: 70% by weight to 8
0: 20% by weight, the aliphatic polyol (d) and / or
Alternatively, the aliphatic polycarboxylic acid (c) acts as a polyfunctional branching agent or a partial crosslinking agent, and is used in an amount of 0.01 to 100 parts by weight in total of the aliphatic dicarboxylic acid and the aliphatic diol.
To 20 parts by weight, preferably 0.1 to 5 parts by weight. Examples of the aliphatic dicarboxylic acid (a) include oxalic acid, succinic acid, adipic acid and the like. As the aliphatic diol (b), ethylene glycol, 1,4
-Butanediol, neopentyl glycol and the like. Examples of the aliphatic polycarboxylic acid (c) include propanetricarboxylic acid and butanetetracarboxylic acid. Examples of the aliphatic polyol (d) include glycerin, diglycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, and 3-methylpentanetriol. Specific examples of the combination of the aliphatic dicarboxylic acid and the aliphatic diol include succinic acid and / or adipic acid and 1,4-butanediol; succinic acid and ethylene glycol; oxalic acid and neopentyl glycol; 1,4-butanediol; oxalic acid and ethylene glycol can be exemplified, but succinic acid and 1,1-butanediol are preferred.
4-butanediol. Particularly preferred resins of the aliphatic polyester resin (I ') used in the present invention are polyester resins obtained from succinic acid, 1,4-butanediol, and a small amount of trimethylolpropane. As the number average molecular weight of the aliphatic polyester resin (I '),
1,000-500,000, preferably 50,000
The range is more preferably 100,000 or more. By doing so, an aliphatic polyester resin (I ′) having an MT of 2 g or more and an MFR of 1 to 9 g / 10 minutes can be obtained.

The aliphatic polyester resin (I ") comprises a linear or branched aliphatic dicarboxylic acid having 1 to 10 carbon atoms (a) and a linear or branched aliphatic diol having 1 to 10 carbon atoms (b). The linear aliphatic polyester (i) is modified with a diisocyanate (e) and / or a tri- or higher functional polyisocyanate (f).

The linear aliphatic polyester (i) has the same number of carbon atoms as described for the aliphatic polyester resin (I ').
Linear or branched aliphatic dicarboxylic acid (a) having 1 to 1 carbon atoms
Aliphatic polyesters composed of 10 linear or branched aliphatic diols (b) or biodegradable polyester resins such as synthetic polylactic acid, JP-A-9-235360, JP-A-9-235360;
No. 233,956, terpolymer aliphatic polyesters described in each publication, lactic acid and hydroxycarboxylic acid copolymers described in JP-A-7-177826, polyamide ester resin synthesized from ε-caprolactone and ε-caprolactam, And polyamino acid resins. Examples of the linear aliphatic polyester (i) comprising an aliphatic dicarboxylic acid (a) and an aliphatic diol (b) include succinic acid and / or adipic acid and 1,4-butanediol; succinic acid and ethylene glycol; Acids and neopentyl glycol; oxalic acid and 1,4-butanediol; aliphatic polyester resins from oxalic acid and ethylene glycol can be exemplified, but aliphatic polyester resins of succinic acid and 1,4-butanediol are preferred. . The MFR of the linear aliphatic polyester (i) is usually 2.0 to 6.0 g / 10
Min and MT is 0.5-2.0 g. The number average molecular weight of the linear aliphatic polyester (i) is 1,0
The range is from 00 to 50,000, preferably 10,000 or more, and more preferably 50,000 or more.

The linear aliphatic polyester (i) is reacted with a diisocyanate (e) and / or a trifunctional or higher polyisocyanate (f) to form an aliphatic polyester resin (I ″). Hexamethylene diisocyanate, isophorone diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, 1,5
-Naphthylene diisocyanate or a mixture thereof, and examples of the tri- or higher functional polyisocyanate (f) include triphenylmethane triisocyanate, hydrogenated triphenylmethane triisocyanate, and lysine diisocyanate methyl ester {OCN- (CH ₂ ) ₄ -CH (-NC
O) -COOCH ₃ }, trimethylhexamethylene diisocyanate, an adduct of the above diisocyanate with a polyhydric alcohol, a trimer of the above diisocyanate, or a mixture thereof. In particular, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate,
Aliphatic and alicyclic isocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, and hydrogenated triphenylmethane triisocyanate are also suitable from the viewpoint of preventing coloring of the polyester resin. The number average molecular weight of the linear aliphatic polyester (i) before modification is 1,0
It is in the range of 00 to 50,000, preferably 5,000 or more, and more preferably 10,000 or more. The number average molecular weight of the aliphatic polyester resin (I ″) obtained by the modification is in the range of 10,000 to 500,000, preferably 50,000 or more, more preferably 100,000 or more. The amount is determined so that the MT and MFR are within the predetermined ranges with respect to the linear aliphatic polyester (i).
Thus, an aliphatic polyester resin (I ") having an MFR of 1 to 9 g / 10 minutes is obtained.

Polycaprolactone (II) The polycaprolactone (II) has an MT of 2 g or more, preferably 5 to 10 g, particularly preferably one which does not break (bag break when formed into a bag), and has an MFR of 1 to 9 g / g.
The time is 10 minutes, preferably 2 to 7 g / 10 minutes, particularly preferably 2 to 5 g / 10 minutes. In addition, the melting point is 60 ° C. or more,
Those having thermoplasticity are preferred. The polycaprolactone (II) used in the present invention is a polycaprolactone (I) obtained by crosslinking linear polycaprolactone (ii).
I ′), or ε-
Polycaprolactone (II ") obtained by polymerizing caprolactone.

The linear polycaprolactone (ii) is selected from water,
Polycaprolactone obtained by polymerizing ε-caprolactone using a monol, diol, monocarboxylic acid, dicarboxylic acid, or hydroxycarboxylic acid as an initiator. Examples of the monol include linear or branched aliphatic or aromatic alcohols having 1 to 10 carbon atoms such as methanol, ethanol, various propanols, various butanols, various octanols, allyl alcohol, and benzyl alcohol. Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, tripropylene glycol,
Examples thereof include polypropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-butene-1,4-diol, cyclohexanediol, and xylylene glycol. Examples of the monocarboxylic acid include formic acid, acetic acid, propionic acid,
(Meth) acrylic acid, benzoic acid and the like. Examples of the dicarboxylic acid include the aliphatic dicarboxylic acids (a). Examples of the hydroxycarboxylic acid include glycolic acid, lactic acid, and hydroxybutyric acid. In addition, the linear polycaprolactone (ii) includes, in addition to the homopolymer of ε-caprolactone, a comonomer structural unit such as valerolactone, glycolide, or lactide, for example, 2
A copolymer containing 0 mol% or less can also be used. The linear polycaprolactone (ii) has a number average molecular weight of 1,000 to 1,000,000, preferably 5,
000 to 500,000, more preferably 10,000
0 to 200,000, particularly preferably 40,000 to 1
00000 polycaprolactone can be used. The polycaprolactone having the above-mentioned molecular weight has a relative viscosity of 1.15 to 2.80 according to JIS K6726, and particularly preferably has a relative viscosity of 1.50 to 2.80. The MFR of the linear polycaprolactone (ii) is usually 2.0 to 6.0 g / 10 min, and the MT is 0.5 to 2.0 g.
0 g. Therefore, it is difficult to form a thin film using the linear polycaprolactone (ii) alone or in combination with the linear polycaprolactone (ii) and the linear aliphatic polyester (i). The molecular weight of the linear polycaprolactone (ii) can be used from a low molecular weight to a high molecular weight. However, when a low molecular weight polycaprolactone is used, the heat resistance and mechanical strength of the kneaded resin are greatly reduced. Although limited, advantages such as a decrease in the melt viscosity of the resin composition and an improvement in moldability are exhibited.
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.

The crosslinked polycaprolactone (II ') is obtained by crosslinking the above-mentioned linear polycaprolactone (ii) in the solid state, in a molten state, or in a solidified state after melting by irradiation with an electron beam, γ-ray or the like. Or crosslinking by heat or light by adding a crosslinking agent. Examples of the crosslinking agent include peroxides alone, and mixtures of peroxides with quinone dioximes, unsaturated acids, and vinyl compounds. The crosslinked polycaprolactone (II ') has a gel fraction of 0.01 to 90%, preferably 0.1 to 70%, and more preferably 1 to 50%. The gel fraction is measured by the following method. A thin plate having a thickness of about 5 mm was cut out from the obtained cross-linked polycaprolactone, wrapped in a 200-mesh stainless steel wire mesh, immersed in acetone for 12 hours, and determined for the gel fraction (the ratio of insoluble components, which indicates the degree of crosslinking). It is determined by the formula. Gel fraction (%) = (W ₂ / W ₁ ) × 100 (where W ₁ represents the dry weight of crosslinked polycaprolactone before immersion, and W ₂ represents the dry weight of insoluble matter after immersion.)

Polycaprolactone (II ") is a polyfunctional initiator, in particular, a trifunctional or higher polyol, which is used as an initiator.
-A copolymer containing, for example, 20 mol% or less of a comonomer constituent unit such as valerolactone, glycolide, or lactide in addition to the homopolymer of caprolactone. Examples of the polyfunctional initiator include compounds and polymers containing three or more active hydrogens such as a hydroxyl group, an amino group, a carboxyl group, and a thiol group in a molecule. Specifically, glycerin,
Radicals in the molecule such as trimethylolpropane, trimethylolethane, pentaerythritol, pyrogallol, oxyhydroquinone, aminopropanediol, erythrose, malic acid, tartaric acid, pentaerythritol-tetramercaptoacetate, and 2-ethylhydroxy (meth) acrylate Oligomers of compounds having both polymerizable double bonds and hydroxyl groups, copolymers with other radically polymerizable monomers and graft-modified products to various polymers, ethylene oxide, graft-modified products to various polymers of propylene oxide, Examples include sugar, starch, cellulose, and polybutadiene having a hydroxyl group. Polycaprolactone (II ") is disclosed in
It can be produced by a known method described in No. 52352. The polycaprolactone (II ") has a number average molecular weight of 5,000 to 1,000,000.
0, preferably 10,000 to 500,000, more preferably 50,000 to 400,000.

As described above, when the aliphatic polyester resin (I) is used, a linear type polycaprolactone (ii) or polycaprolactone (II) can be used as the polycaprolactone. In Although,
Preferably, it is a linear polycaprolactone (ii).
When using polycaprolactone (II),
As the aliphatic polyester resin, a linear aliphatic polyester resin (i) or an aliphatic polyester resin (I) can be used, but a linear aliphatic polyester resin (i) is preferable. . Alternatively, it is a composition comprising an aliphatic polyester resin (I) and / or an aliphatic polyester resin (i) and polycaprolactone (II) and / or polycaprolactone (ii), wherein the composition has an MT of 2 g or more, Preferably 5 to 10 g,
It is particularly preferable that it does not break (when it is made into a bag), and that the MFR is 1 to 9 g / 10 min, preferably 2 to 7 g / 10 min, and particularly preferably 2 to 5 g / 10 min.
Use what is a minute. With these, a thin film can be formed.

Examples of commercially available linear aliphatic polyesters (i) include Bionole containing no urethane bond (manufactured by Showa Polymer Co., Ltd.) and ECOPLA made of polylactic acid.
(Manufactured by Cargill), Lacty (manufactured by Shimadzu), Lacia (manufactured by Mitsui Chemicals), and the like. Examples of commercially available aliphatic polyester resin (I) include Bionole # 190
3 (manufactured by Showa Polymer Co., Ltd.). Examples of commercially available polycaprolactone (ii) include Plaxel H7
(Manufactured by Daicel Chemical Industries, Ltd.). Examples of commercially available products of polycaprolactone (II) include those using Plaxel 303, 30 as those using a tri- or higher functional polyol as an initiator.
5,405 and the like.

In the following, when it is not necessary to distinguish between polycaprolactone (II) and polycaprolactone (ii) and between aliphatic polyester resin (I) and aliphatic polyester resin (i), only polycaprolactone, Group polyester resin. The weight ratio of polycaprolactone to aliphatic polyester resin is such that polycaprolactone: aliphatic polyester resin is 70: 30% by weight to 5: 5%.
95% by weight, preferably 50: 50% to 30: 70%
% By weight. In this case, if the polycaprolactone exceeds the above range, the mechanical properties of the film at high temperatures tend to decrease.

The composition of the aliphatic polyester and the polycaprolactone can be added with a known resin additive, if necessary, to form a film. As resin additives, plasticizers, heat stabilizers, lubricants, antiblocking agents, nucleating agents, photolytic agents, biodegradation accelerators, antioxidants, autoxidants, ultraviolet stabilizers, antistatic agents, conductive agents, Flame retardant, dropping agent, cross-linking agent, antibacterial agent, deodorant, filler, colorant, starch,
Resin components other than the polycaprolactone and the aliphatic polyester resin (for example, ethylene copolymer and other polyolefins, hydrogenated styrene-butadiene rubber, polyurethane, polyamide, polyhydroxybutyrate, and the like), or a mixture thereof. In particular, the addition of a photodegradation accelerator, an autoxidizing agent, and the like is preferable in order to impart brittleness to the film around a desired period of time.

Examples of the plasticizer usable in the present invention include aliphatic dibasic acid esters, phthalic acid esters, hydroxy polycarboxylic acid esters, polyester plasticizers, fatty acid esters, epoxy plasticizers, and mixtures thereof. . For example, phthalic acid esters such as di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), diisodecyl phthalate (DIDP), di-2-ethylhexyl adipate (DOA), diisodecyl adipate (DIDA) Adipic acid esters such as azelaic acid-di-2-ethylhexyl (DOZ), hydroxy polyvalent carboxylic acid esters such as acetyl citrate tri-2-ethylhexyl and acetyl tributyl citrate, and polypropylene glycol adipate Polyester plasticizer such as
These are used in one kind or in a mixture of two or more kinds. Preferably, di-2-ethylhexyl azelate (D
OZ). As the addition amount of these plasticizers,
The range is preferably 3 to 30 parts by weight based on 100 parts by weight of the total of polycaprolactone and aliphatic polyester resin. Further, it is preferably 5 to 15 parts by weight. If the amount is less than 3 parts by weight, the elongation at break and the impact strength become low, and if it exceeds 30 parts by weight, the strength at break and the impact strength decrease, which is not preferable.

The heat stabilizer that can be used in the present invention includes an aliphatic carboxylate. As the aliphatic carboxylic acid, an aliphatic hydroxycarboxylic acid is particularly preferred. As the aliphatic hydroxycarboxylic acid, naturally occurring ones such as lactic acid and hydroxybutyric acid are preferable. Examples of the salt include salts of sodium, calcium, aluminum, barium, magnesium, manganese, iron, zinc, lead, silver, copper, and the like. These can be used as one kind or as a mixture of two or more kinds. The amount added is in the range of 0.5 to 10 parts by weight, preferably 0.5 part by weight, based on 100 parts by weight of the total of polycaprolactone and the aliphatic polyester resin.
-5 parts by weight. When the heat stabilizer is used in the above range, the impact strength (dirt impact value) is improved, and there is an effect that variations in elongation at break, strength at break, and impact strength are reduced.

Examples of the photolysis accelerator include benzophenones such as benzoins, benzoin alkyl ethers, benzophenone and 4,4-bis (dimethylamino) benzophenone and derivatives thereof; acetophenone,
Acetophenones such as α, α-diethoxyacetophenone and derivatives thereof; quinones; thioxanthones; photoexciting materials such as phthalocyanine, anatase-type titanium oxide, ethylene-carbon oxide copolymer, sensitization of aromatic ketones with metal salts And the like. These photolysis accelerators are
One type or two or more types can be used in combination.

Examples of the biodegradation accelerator include oxo acids (eg, oxo acids having about 2 to 6 carbon atoms such as glycolic acid, lactic acid, citric acid, tartaric acid, malic acid, etc.) and saturated dicarboxylic acids (eg, oxalic acid). Organic acids such as acids, malonic acid, succinic acid, succinic anhydride, glutaric acid, etc .; lower saturated dicarboxylic acids having about 2 to 6 carbon atoms); these organic acids and alcohols having about 1 to 4 carbon atoms. Lower alkyl esters are included. Preferred biodegradation promoters 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 are also 1
Species or two or more can be used in combination.

As the lubricant, a commonly used internal lubricant and / or external lubricant can be used. For example, fatty acid esters, hydrocarbon resins, paraffin, higher fatty acids,
Oxy fatty acids, fatty acid amides, alkylene bis fatty acid amides, aliphatic ketones, fatty acid lower alcohol esters,
Examples thereof include fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, fatty alcohols, polyhydric alcohols, polyglycols, polyglycerols, metal soaps, modified silicones, and mixtures thereof. Preferably, fatty acid esters, hydrocarbon resins and the like are used. When selecting an appropriate fatty acid amide from the above fatty acid amide,
Of course, it is necessary to select a fatty acid amide having a melting point or lower according to the melting point of various aliphatic polyester resins to be blended. For example, in consideration of the melting point of the aliphatic polyester resin, a fatty acid amide having a melting point of 160 ° C. or lower is selected as the fatty acid amide. Among the above fatty acid amides, from the viewpoint of preventing environmental pollution, high safety and FDA
Ethylene bisstearic amide, stearic amide, oleic amide, and erucamide registered with the US Food and Drug Administration are preferred. The compounding amount is 0.05 to 5 parts by weight of a lubricant, preferably 0.1 to 100 parts by weight of polycaprolactone and an aliphatic polyester resin in total.
Add ~ 3 parts by weight. If the amount is less than 0.05 part by weight, the effect is not sufficient, and if the amount is more than 5 parts by weight, the material is not wound around a roll, and the physical properties are deteriorated. Commercial products include RIQUESTER EW-100 (manufactured by Riken Vitamin Co.) and Hoechst Wax OP (manufactured by Hoechst).

The liquid lubricant as a wetting agent preferably has a melting point of 70 ° C. or lower, and more preferably a liquid lubricant at room temperature. For example, in addition to liquid paraffin, paraffin wax, stearyl alcohol, stearic acid, etc., stearic acid esters such as butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, stearyl stearate and the like can be mentioned.

The most preferred liquid paraffin in the above liquid lubricants has an oral acute toxicity (rat) LD50 of 5 g / k.
g, it is very safe, is recognized as a food additive under the Food Sanitation Act, and is a very convenient material in terms of preventing environmental pollution when the film is discarded. As described above, a liquid lubricant was selected as the lubricant, but if a solid lubricant is used, the entire system including the resin composition needs to have a melting point of the solid lubricant or higher, and a low temperature of the melting point or lower. It is difficult to use. Liquid paraffin, which is liquid at room temperature, is a preferred lubricant in this regard.

The purpose of using the liquid lubricant is that polycaprolactone or an aliphatic polyester resin is usually supplied in the form of pellets or beads, and when it is desired to uniformly mix finely powdered silica or the like having a very low bulk specific gravity with the pellets or beads. This is because it is preferable to keep the surface of the beads as wet as possible. The amount of the liquid lubricant having such a purpose of use is preferably from 0.1 to 100 parts by weight of the total amount of polycaprolactone and aliphatic polyester resin.
3 parts by weight, more preferably 0.2 to 0.7 parts by weight. If the added amount exceeds 3 parts by weight, a large amount of the liquid lubricant adheres to the inner surface of the mixing tumbler, and sticky and stable mixing may be difficult. If the added amount is less than 0.1 part by weight, the effect as a wetting agent is sufficient. May not be able to demonstrate. This tendency is more preferable from 0.2 to 0.1.
It is also found outside the range of 7 parts by weight.

Examples of the filler include fine powder silica, talc, calcium carbonate, mica, calcium silicate, white carbon, asbestos, porcelain clay (fired), glass fiber and the like. The use of the fine powder silica is intended to prevent blocking of the film. The fine powdered silica used may be silica produced by a wet method, silica produced by high-temperature hydrolysis of silicon tetrachloride in an oxyhydrogen flame, and the like, particularly those having a particle size of 50 nm or less. Is preferred. As the addition method, the aliphatic polyester resin according to the present invention alone, the method of heating and kneading the composition comprising polycaprolactone and the aliphatic polyester is most preferable, and the secondary aggregated particles are loosened by the action of a considerably high shear force. It exhibits the effect of preventing film blocking. The addition amount of the finely divided silica is most preferably in the range of 0.1 to 3 parts by weight based on 100 parts by weight of the total amount of polycaprolactone and the aliphatic polyester resin from the viewpoint of exhibiting the above effects.

When the biodegradable film is used for an object where charging is a problem, conductive materials such as carbon, metal powder, and conductive resin, and known nonionic, cationic or anionic antistatic agents are used. used.

[0033] Starch includes raw starch, processed starch and mixtures thereof. As raw starch, corn starch, potato chopsticks starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, rice starch, legume starch,
Kudzu starch, bracken starch, lotus starch, Japanese cinnamon starch and the like, and the modified starches include physically modified starches (α-starch, fractionated amylose, wet heat-treated starch, etc.), and enzyme-modified starches (hydrolyzed dextrin, enzyme-decomposed dextrin). , Amylose, etc.), chemically modified starch (acid-treated starch, hypochlorite oxidized starch, dialdehyde starch, etc.), chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, cross-linked starch, etc.). No. Among the above, as the esterified starch, acetate-starch, succinate-starch, nitrate-starch, phosphate-starch, urea-phosphate-starch, xanthate-starch, acetoacetate-starch Etc .; as etherified starch, allyl etherified starch, methyl etherified starch, carboxymethyl etherified starch, hydroxyethyl etherified starch, hydroxypropyl etherified starch, etc .; as cationized starch, starch and 2-diethylaminoethyl chloride And the reaction product of starch and 2,3-epoxypropyltrimethylammonium chloride; crosslinked starch includes formaldehyde crosslinked starch;
Epichlorohydrin cross-linked starch, phosphoric acid cross-linked starch, acrolein cross-linked starch and the like. The amount of the starch added is not particularly limited. However, in order to effectively achieve the purpose of adding biodegradability, 10% by weight of the total amount of polycaprolactone and aliphatic polyester resin is 100 parts by weight. The amount is preferably from 80 to 80 parts by weight, and particularly preferably from 25 to 50 parts by weight.

As the coloring agent, known dyes and pigments can be used. As a result, a desired color, design, and packaging suitable for plants and growth can be obtained.

As a method for kneading polycaprolactone with an aliphatic polyester resin and a resin additive to be added as required, a general method can be preferably used. Specifically, pellets, powders, solid flakes and the like can be used. Can be dry-mixed with a Henschel mixer or a ribbon mixer, and supplied to a known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll to be melt-kneaded.
Also, when adding liquid polycaprolactone,
Kneading can be performed in a similar manner. For example, to explain an example of a production method of the composition, first, polycaprolactone and an aliphatic polyester and a liquid lubricant are mixed in a tumbler with stirring for 10 to 20 minutes, and then a fatty acid amide is added, and fine silica powder and starch powder are added thereto. And mix with stirring for another 20-30 minutes. Thereafter, the mixture is melt-kneaded at about 140 to 210 ° C. by a single-screw or twin-screw extruder or the like to obtain pellets of the resin composition containing various additives.

When the aliphatic polyester resin and the polycaprolactone are kneaded, it is preferable that they are compatible with each other from the viewpoint of the mechanical properties of the resin composition obtained by kneading. For example, a compatibilizer such as a copolymer of a kneaded resin component and a polycaprolactone component,
For example, addition of a resin having a polarity intermediate between the two can also be preferably used.

The film can be processed by various conventional molding methods such as an inflation method and a T-die method. The production speed of the film by the above method is 10 to 30 m / min, preferably 15 to 20 m / min, and the time for continuous production without film breakage is 1 hour or more, preferably 3 hours or more, and more preferably. Is at least 10 hours, particularly preferably at least 24 hours. The film may be uniaxially or biaxially stretched. The stretched film can also be used as a film for a biodegradable film of a shrink type.

The thickness of the film is 5 to 25 μm, preferably 10 to 20 μm. Conventionally, when trying to form such a thin film continuously, the film was frequently cut, but by using the composition of the present invention,
The film can be formed continuously for a long time without breaking the film.

The use of the biodegradable film of the present invention is not particularly limited. Preferably, the biodegradable film can be used after being used and may be left in a natural environment. For example, agricultural films, garbage bags, bubble cushioning materials, and the like.

[0040]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In the Examples, “%” and “parts” are based on weight unless otherwise specified. The MFR is 190
It is a value showing the flow characteristics at a load of 2,160 g at ° C. MT is the tension at the time of resin melting. Using a Capillograph, resin extrusion cylinder temperature 150 ° C,
Cylinder speed 1mm / min, extrusion diameter 1mmφ, L / D
= 10, inflow angle = 90 degrees, extruded into a rod, take-off speed 10
m / min, distance between capillary and load cell 50cm,
The tension (g) when the extruded rod-shaped resin is pulled is shown. The higher the melt tension without breaking at a high take-off speed, the better the processability of the film. Mechanical properties Tensile yield stress, tensile rupture stress, tensile rupture elongation (%), and tensile modulus are in accordance with JIS K-7113. Izod impact strength (23 ° C.) is based on JIS K-7110. Biodegradability test: Biodegradability was measured using a film resin powder as a sample. The method for evaluating the biodegradability of a sample is based on JIS
There are various methods such as using activated sludge according to K6950, burial in soil, immersion in seawater or rivers, evaluation in compost, and the like. JIS K695 that there is
Performed according to 0.

The following resins were used as raw materials. Aliphatic polyester: Bionole # 1903 (manufactured by Showa Polymer Co., Ltd., MFR 5.5 g / 10 min, MT 6.5)
g), Bionore # 1001 (manufactured by Showa Polymer Co., Ltd., M
FR 2.0 g / 10 min, MT 1.5 g) Bifunctional polycaprolactone: Praxel H7 (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 70,000, MFR)
2.3 g / 10 min, MT 1.0 g) Trifunctional polycaprolactone: Daicel Chemical Industries, Ltd.
Manufactured, number average molecular weight 100,000

Example 1 A resin composition (MFR 3.9 g / 10 minutes, MT 3.5 g) was obtained by mixing Bionole # 1903 and Plaxel H7 in a weight ratio of 50:50. Using this composition, a thickness of 10, 15,
Each film of 20 and 25 μm was produced, and all of them could be produced without breaking the film for 6 hours. The tensile yield stress of the film was converted to a thickness of 30 μm, 310 kgf / cm ² , tensile breaking stress 400 kgf / cm ² ,
Tensile elongation at break of 590%, tensile modulus of elasticity of 3100 kgf / cm ² ,
The Izod impact strength (23 ° C.) was 41 kgf · cm / cm ² and the biodegradability was 71%.

[Comparative Example 1] A resin composition (MFR 2.0 g / 10 min, MFR) was prepared by mixing Bionole # 1001 (manufactured by Showa Polymer Co., Ltd.) and Plaxel H7 at a weight ratio of 50:50.
T1.2 g). Production of each film having a thickness of 15 or 25 μm was attempted using this composition by the T-die method, but it was difficult to produce films continuously because of poor film production.

Example 2 A resin composition (3.2 g / 10 min MFR, 3.2 g MT4.) Of Bionore # 1001 and Plaxel, a polycaprolactone having a trifunctional polyol as an initiator, were mixed at a weight ratio of 50:50. 5 g) were obtained.
Using this composition, a film having a thickness of 20 μm was produced by the T-die method, but the film could be produced without breaking the film for 12 hours.

[Preparation Example 1] Production of Irradiated Cross-Linked Polycaprolactone Pluxel H7 pellets were placed in a glass ampoule, connected to a vacuum line to remove air, and then sealed.
Dose rate 10 kGy / hr by gamma rays from cobalt 60
At 100 kGy. The gel fraction of the obtained irradiation-crosslinked polycaprolactone was 70%. Furthermore, a PC sliced to a thickness of 2 to 3 mm to examine heat resistance
L is compression-molded into a film by hot pressing at 200 ° C., and the tensile speed is 100 mm / m using a high-temperature tensile tester.
in, and measured at 120 ° C., the tensile strength was 2 MPa and the elongation at break was 550%. Biodegradability was 55% for unirradiated Plaxel H7, but improved to 80% for the irradiated product.

Example 3 Polycaprolactone radiation-crosslinked with γ-rays from cobalt 60 and Vionore # 1001 were mixed at a weight ratio of 50:50 so as to have the same melt tension as the above-mentioned radiation-crosslinked polycaprolactone. . The MI of this mixture was 2.5 g / 10 min, and the MT was 6.5 g. To 100 parts by weight of the resin mixture, 0.5 part of liquid paraffin and stearamide 1
Part is a twin screw type vented extruder (40 mm
(Diameter) and extruded at a die temperature of 180 ° C. to obtain pellets of the resin composition. Using these pellets, thickness 20
A film of μm was produced, but it could be produced without breaking the film for 3 hours.

[0047]

According to the present invention, a thin biodegradable film having good continuous formability, excellent appearance and strength, and high biodegradation rate can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 5/07 C08K 5/07 5/08 5/08 5/098 5/098 5/10 5/10 5/20 5 / 20 5/46 5/46 C08L 67/02 ZAB C08L 67/02 ZAB 67/04 67/04 F term (reference) 4F071 AA43 AA44 AA71 AA74 AB17 AB21 AB26 AC02 AC05 AC07 AC09 AC10 AC12 AC13 AE04 AE05 AE11 AE16 AE22 AF52 AH04 AH19 BB06 BB07 BB08 BC01 4J002 AE053 CF03W CF19X CP033 DE138 DE239 DJ019 DJ049 DJ059 EC009 EE028 EE058 EF008 EF059 EG007 EH006 EH008 EH009 EN008 EP009 EV318 FD019 FD026 FD0100 FD026 FD0100 FD026 FD0100 HC03 HC12 HC13 HC22 HC23 JA01

Claims (11)

[Claims] 1. A composition comprising an aliphatic polyester resin and a polycaprolactone, wherein the aliphatic polyester resin has a melt tension of 2 g or more, a melt flow rate of 1 to 9 g / 10 min, and the polycaprolactone is a linear type. Polycaprolactone with a film thickness of 5-2
Biodegradable film that is 5 μm. 2. A composition comprising an aliphatic polyester resin and polycaprolactone, wherein the polycaprolactone has a melt tension of 2 g or more and a melt flow rate of 1
-9 g / 10 min, the aliphatic polyester resin is a linear aliphatic polyester resin, and the film thickness is 5
Biodegradable film of ２５25 μm. 3. A composition comprising an aliphatic polyester resin and polycaprolactone, wherein the composition has a melt tension of 2 g or more and a melt flow rate of 1 to 9 g.
/ 10 min, and a biodegradable film having a film thickness of 5 to 25 μm. 4. The method according to claim 1, wherein the aliphatic polyester resin is a polyester resin containing a structural unit of an aliphatic dicarboxylic acid, an aliphatic diol, and a trifunctional or higher aliphatic polycarboxylic acid and / or an aliphatic polyol. Claim 1
Or the biodegradable film according to 3. 5. The aliphatic polyester resin uses succinic acid and / or adipic acid as a dicarboxylic acid component and ethylene glycol and / or 1,4 as a diol component.
The biodegradable film according to any one of claims 1 to 4, which is a polyester resin containing a structural unit of -butanediol. 6. The biodegradable film according to claim 1, wherein the aliphatic polyester resin is modified with diisocyanate and / or tri- or higher functional polyisocyanate. 7. The diisocyanate and / or trifunctional or higher polyisocyanate is hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, hydrogenated triphenylmethane triisocyanate, or a mixture thereof. The biodegradable film according to claim 6, which is a mixture of: 8. The raw material according to claim 2, wherein the polycaprolactone is a crosslinked polycaprolactone, or a product obtained by polymerization using a polyol having three or more functional groups as an initiator. Degradable film. 9. The biodegradable film according to claim 1, wherein the content of polycaprolactone to aliphatic polyester resin is from 70 to 30% by weight to 5 to 95% by weight. 10. A composition comprising an aliphatic polyester resin and polycaprolactone, a plasticizer, a heat stabilizer, a lubricant, an anti-blocking agent, a nucleating agent, a photolytic agent, a biodegradation accelerator, an antioxidant, an ultraviolet stabilizer, The biodegradable film according to any one of claims 1 to 3, further comprising an antistatic agent, a conductive agent, a flame retardant, a dropping agent, an antibacterial agent, a deodorant, a filler, a colorant, or a mixture thereof. 11. The biodegradable film according to claim 1, wherein the film is uniaxially or biaxially stretched.