JP2010155392A - Biodegradable resin laminate and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable resin laminate having superior moldability and mechanical properties while retaining characteristics of biodegradability and controlling surface precipitation of low-molecular oligomers. <P>SOLUTION: The biodegradable resin laminate includes at least three layers a pair of surface layers constituting the front and the back surface and an intermediate layer formed across the pair of the surface layers. The pair of the surface layers are each made of an aliphatic polyester type resin (A), and the intermediate layer is made of an aliphatic aromatic polyester type resin (B). The amount of low-molecular oligomers in the aliphatic polyester type resin (A) is 1,000-10,000 ppm, based on the mass of the aliphatic polyester type resin (A). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a biodegradable resin laminate and a method for producing the same. Specifically, the present invention relates to a biodegradable resin laminate excellent in biodegradability and excellent in elastic modulus and tear strength, and a method for producing the same.

  In modern society, various materials such as paper, plastic, and aluminum foil are used for various foods, medicines, miscellaneous products such as liquids and granules, solid packaging materials, agricultural materials, and building materials. Is used. Among them, plastics are excellent in strength, water resistance, moldability, transparency, cost, etc., and are therefore used in a wide range of applications as molded articles such as bags and containers. Currently, plastics widely used for applications such as bags and containers include polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate. However, molded articles made of the above-mentioned plastics do not biodegrade or hydrolyze in the natural environment, or the degradation rate is extremely slow, so when they are buried after use, they remain in the soil or are dumped. If this happens, the scenery may be damaged. Moreover, even when incinerated, there are problems such as generating harmful gases and damaging the incinerator.

  Biodegradable resins have been attracting attention as environmentally friendly plastics that solve these problems. Since the film formed by molding the biodegradable resin is decomposed in the soil by embedding in the soil after use, it is possible to prevent global warming and soil and air pollution. Therefore, in recent years, many biodegradable resin films are being used for garbage bags, shopping bags, and the like. However, since many of these biodegradable resin films are generally inferior in mechanical properties, research for improving the mechanical properties of biodegradable films while maintaining good biodegradability has been conducted. Many have been made.

For example, in Patent Document 1, a composition of an aliphatic aromatic polyester resin and an aliphatic polyester resin is used for the surface layer, and an aliphatic polyester resin is used for the intermediate layer to form a film by biaxial stretching. A biodegradable film is disclosed. Patent Document 2 discloses a film in which an aliphatic polyester-based resin with reduced low molecular weight oligomers is laminated on the surface layer and an aliphatic aromatic polyester-based resin is laminated on the intermediate layer.
JP 2006-137157 A JP 2008-101335 A

  By the way, when using a biodegradable resin for daily commodities such as garbage bags and shopping bags, it is necessary to consider the appearance and safety in addition to the mechanical properties. In particular, when an aliphatic polyester-based resin is used as a biodegradable film, a generally produced aliphatic polyester-based resin contains a low molecular weight oligomer. There is a problem that the oligomer sticks or slips on the hand when touched. In addition, hygienic problems may occur depending on the application such as food packaging.

  In this regard, in Patent Document 1, a resin composition in which two or more kinds of biodegradable resins are mixed is formed into a film, but only a laminate satisfying the mechanical properties of a practical film is manufactured. The problem of low molecular weight oligomer precipitation could not be solved.

  Moreover, in patent document 2, the balance of a physical property and precipitation of the low molecular weight oligomer which precipitates by using the aliphatic polyester-type resin which reduced the low molecular weight oligomer for the surface layer, and making thickness of a laminated body very thick with 100 micrometers-600 micrometers. Reduction is realized. However, in order to reduce low molecular weight oligomers as in the aliphatic polyester resin used in Patent Document 2, it is necessary to go through a very complicated process in terms of work, such as solvent extraction to remove low molecular weight oligomers. was there. When solvent extraction is performed, there are problems that the resin hurts, the solvent remains in the resin, making it difficult to use for food contact applications, and the process using the solvent increases, resulting in an increase in cost.

  The present invention has been made in view of the above problems, and provides a biodegradable resin laminate having excellent moldability and mechanical properties while suppressing surface precipitation of low molecular weight oligomers while maintaining biodegradable characteristics. The issue is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by producing a laminate with a specific resin and configuration, and have completed the present invention.

  That is, the first aspect of the present invention is a biodegradable resin laminate comprising at least three layers of a pair of surface layers forming a front surface portion and a back surface portion and an intermediate layer provided between the pair of surface layers. The pair of surface layers are each made of an aliphatic polyester-based resin (A), and the intermediate layer is made of an aliphatic aromatic polyester-based resin (B). The low-molecular weight oligomer in the aliphatic polyester-based resin (A) Is to provide a biodegradable resin laminate characterized in that it is 1000 to 10,000 ppm based on the mass of the aliphatic polyester resin (A).

  In the first aspect, the aliphatic polyester resin (A) preferably includes a diol unit and a dicarboxylic acid unit as constituent units.

  In the first embodiment, the aliphatic polyester resin (A) is a polybutylene succinate resin and / or a polybutylene succinate adipate resin, and the aliphatic aromatic polyester resin (B) is a polybutylene succinate resin. A butylene adipate terephthalate resin is preferred.

  Moreover, in the first aspect, the ratio of the thickness of the three surface layers / intermediate layer / surface layer of the biodegradable resin laminate is preferably in the range of 1/10/1 to 10/1/10.

  The second aspect of the present invention comprises the aliphatic polyester resin (A), and the amount of the low molecular weight oligomer in the aliphatic polyester resin (A) is 1000 based on the mass of the aliphatic polyester resin (A). A method for producing a biodegradable resin laminate comprising at least three layers of a pair of surface layers of 10000 ppm and an intermediate layer composed of an aliphatic aromatic polyester resin (B) provided between the pair of surface layers. The ratio of the three surface layers / intermediate layers / surface layer thicknesses of the biodegradable resin laminate is 1/10/1 to 10/10/10, and the inflation molding is performed. The manufacturing method of a biodegradable resin laminated body is provided and the said subject is solved.

  ADVANTAGE OF THE INVENTION According to this invention, the biodegradable laminated body which was excellent in the moldability, was excellent also in mechanical physical properties, such as an elasticity modulus and tear strength, and the surface precipitation of the low molecular weight oligomer was suppressed. By setting it as the laminated body of the structure of this invention, the surface precipitation of a low molecular weight oligomer can be suppressed effectively, without having to reduce extremely the amount of the low molecular weight oligomer of the aliphatic polyester-type resin of a surface layer. That is, since it is not necessary to excessively perform oligomer removal operations such as solvent extraction on the aliphatic polyester resin as a raw material, it is possible to produce a high-quality and highly safe laminate at low cost. . This laminate can be suitably used for a wide range of applications including various bag products such as garbage bags and shopping bags, as well as containers and packaging that come into contact with food.

  The biodegradable resin laminate of the present invention has a pair of surface layers made of an aliphatic polyester-based resin (A) and an intermediate layer made of an aliphatic aromatic polyester-based resin (B). Hereinafter, each layer and manufacturing method of the biodegradable resin laminate will be described in detail.

  In the present specification, a resin composition containing a specific resin as a component may be called with the name of the resin as the main component. Here, the “main component” refers to a component that occupies 50% by mass or more, preferably 70% by mass or more, particularly 90% by mass or more of the composition. For example, “polybutylene succinate-based resin” refers to a resin composition containing a polybutylene succinate-based resin as a main component.

  Further, in this specification, the term “polymer” refers to a polymer composed of a single type of repeating structural unit (so-called “homopolymer”) and a polymer composed of a plurality of types of repeating structural units (so-called “polymer”). It is used as a concept including “copolymer”).

  In the following description, a partial structural unit of a polymer derived from a certain monomer is represented by adding the word “unit” to the name of the monomer. For example, the partial structural unit derived from dicarboxylic acid is represented by the name “dicarboxylic acid unit”.

  Moreover, the monomer which gives the same partial structural unit is named generically by the name which replaced the "unit" of the name of the partial structural unit with "component." For example, monomers such as aromatic dicarboxylic acids and aromatic dicarboxylic acid diesters form aromatic dicarboxylic acid units, even if the reaction in the process of forming the polymer is different. Therefore, these aromatic dicarboxylic acids and aromatic dicarboxylic acid diesters are collectively referred to as “aromatic dicarboxylic acid component”.

<Surface layer: Aliphatic polyester resin (A)>
The aliphatic polyester resin (A) constituting the surface layer is not limited as long as it is a biodegradable resin, and any known aliphatic polyester can be used as long as the effects of the present invention are not significantly impaired. . Aliphatic polyesters include those in which the main constituents are aliphatic diols and aliphatic dicarboxylic acids, and those in which aliphatic oxycarboxylic acids are the main constituents such as polylactic acid and polycaprolactam. As the aliphatic polyester-based resin (A), one kind may be used alone, or two or more kinds may be used in any combination and in a general ratio as long as the effect of the present invention is not significantly impaired. Good. The aliphatic polyester resin (A) is preferably an aliphatic polyester whose main components are an aliphatic diol and an aliphatic dicarboxylic acid.

Specific examples of such aliphatic polyester include a chain aliphatic and / or alicyclic diol unit represented by the following formula (1) and a chain fat represented by the following formula (2). And / or alicyclic dicarboxylic acid units.
—O—R ¹ —O— (1)
[In the formula (1), R ¹ represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more types of R ¹ may be contained in the resin. ]
^-OC-R 2 -CO- (2)
[In the formula (2), R ² represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more types of R ² may be contained in the resin. ]

  In the above formulas (1) and (2), “and” in the “divalent chain aliphatic hydrocarbon group and / or divalent alicyclic hydrocarbon group” means an aliphatic polyester resin. This means that both a divalent chain aliphatic hydrocarbon group and a divalent alicyclic hydrocarbon group may be contained in one molecule. Hereinafter, “chain aliphatic and / or alicyclic” may be simply abbreviated as “aliphatic”.

  The aliphatic diol component giving the diol unit of the formula (1) is not particularly limited, but an aliphatic diol component having 2 to 10 carbon atoms is preferable, and an aliphatic diol component having 4 to 6 carbon atoms is particularly preferable. Specific examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like.

  The aliphatic dicarboxylic acid component giving the dicarboxylic acid unit of the formula (2) is not particularly limited, but an aliphatic dicarboxylic acid component having 2 to 10 carbon atoms is preferable, and an aliphatic dicarboxylic acid component having 4 to 8 carbon atoms is particularly preferable. preferable. Specific examples include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like.

  1,4-butanediol is particularly preferred as the aliphatic diol component giving the diol unit of the formula (1), and succinic acid or adipine as the aliphatic dicarboxylic acid component giving the dicarboxylic acid unit of the formula (2) Acid is particularly preferred. The aliphatic polyester resin (A) used in the present invention is particularly preferably a polybutylene succinate resin and / or a polybutylene succinate adipate resin.

  In addition, aliphatic oxycarboxylic acid units may be contained in an aliphatic polyester resin mainly composed of an aliphatic diol and an aliphatic dicarboxylic acid. Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2- Examples include hydroxy-3-methylbutyric acid and 2-hydroxyisocaproic acid. These lower alkyl esters and intramolecular esters may also be used. In addition, when optical isomers exist in these, any of D-form, L-form, and racemate may be used, and the form may be any of solid, liquid, or aqueous solution. Among these, lactic acid or glycolic acid is preferable. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

  The amount of the aliphatic oxycarboxylic acid unit is generally 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is the lower limit among all the components constituting the aliphatic polyester resin (A). Usually, it is 30 mol% or less, preferably 20 mol% or less.

  In addition, the aliphatic polyester-based resin (A) is a trifunctional or higher functional compound such as “aliphatic or alicyclic polyhydric alcohol”, “aliphatic or alicyclic polycarboxylic acid or anhydride thereof”, “ It is preferable that at least one of the “aliphatic polyvalent oxycarboxylic acids” is copolymerized because the melt viscosity of the resulting aliphatic polyester resin can be increased.

  Specific examples of the trifunctional aliphatic or alicyclic polyhydric alcohol include trimethylolpropane and glycerin, and specific examples of the tetrafunctional or higher aliphatic or alicyclic polyhydric alcohol include pentaerythritol. It is done.

  Specific examples of the trifunctional aliphatic or alicyclic polycarboxylic acid or its anhydride include propanetricarboxylic acid or its anhydride, and a tetrafunctional aliphatic or alicyclic polycarboxylic acid or its anhydride. Specific examples of the product include cyclopentanetetracarboxylic acid or its anhydride.

  The trifunctional aliphatic polyvalent oxycarboxylic acid includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) one carboxyl group and two hydroxyl groups. Any type can be used. Specifically, malic acid of the type (i) is mentioned. In addition, the tetrafunctional aliphatic polyvalent oxycarboxylic acid component includes (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, and (ii) two carboxyl groups and two And (iii) a type that shares three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used. Specific examples include citric acid and tartaric acid. These may be used alone or in combination of two or more.

  The amount of such a trifunctional or higher functional compound is usually 0.0001 mol% or more, preferably 0.001 mol% or less, based on the whole monomer constituting the aliphatic polyester resin (A) (100 mol%). The upper limit is usually 1 mol% or less, preferably 0.5 mol% or less.

  The production method of the aliphatic polyester resin (A) is not limited as long as the effects of the present invention are not significantly impaired, and can be produced by any known method. For example, it can be produced by a melt polymerization method in which an esterification reaction between a dicarboxylic acid component and a diol component is performed, followed by a polycondensation reaction under reduced pressure, a solution heating dehydration condensation method using an organic solvent, or the like. Among these, from the viewpoint of economy and simplicity of the production process, a melt polymerization method carried out in the absence of a solvent is preferable.

  An additive may be added when producing the aliphatic polyester resin (A). Examples of the additive include carbonate compounds and polyfunctional isocyanate compounds. By mixing these compounds, the structure includes a carbonate bond (hereinafter, this bond portion is particularly referred to as “carbonate bond unit”) and a urethane bond (hereinafter, this bond portion is particularly referred to as “urethane bond unit”). Can be produced. In addition, the carbon chain of the aliphatic polyester resin can be extended.

  The amount of the carbonate bond unit relative to all the structural units of the aliphatic polyester resin (A) is usually 30 mol% or less, preferably 20 mol% or less, more preferably 10 mol% or less, and there is no lower limit. It is not necessary to mix.

  Specific examples of the carbonate compound include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl carbonate, dicyclohexyl carbonate and the like. Is mentioned. In addition, carbonate compounds composed of the same or different hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can be used.

  On the other hand, the amount of urethane bond units relative to all structural units of the aliphatic polyester resin (A) is usually 5 mol% or less, preferably 3 mol% or less, more preferably 1 mol% or less, and the lower limit is There is no need to mix them.

  Specific examples of the polyfunctional isocyanate compound include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, and xylylene. Known diisocyanates such as diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and trifunctional or higher functional isocyanate compounds.

  As examples of other additives, dioxazoline, silicate ester, and the like can be used as a chain extender.

Specific examples of the silicate ester include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxylane. The content of the silicate ester is not limited from the viewpoint of environmental protection and safety. However, since the operation may become complicated and the polymerization rate may be affected, it is preferable that the amount used is small. Specifically, it is preferably 0.1 mol% or less, more preferably 10 ⁻⁵ mol% or less, based on all structural units constituting the aliphatic polyester resin (A).

  In order to increase the melt tension, a small amount of peroxide may be mixed as long as a compound having low toxicity is mixed. Moreover, you may seal a polyester resin terminal group with a carbodiimide compound, an epoxy compound, monofunctional alcohol, or carboxylic acid.

  The aliphatic polyester resin (A) may be derived from biomass resources. There is no restriction | limiting in the kind of biomass resource, or its manufacturing method, unless the effect of this invention is impaired remarkably. For example, biomass resources obtained by induction to a carbon source through any known pretreatment / saccharification process such as chemical treatment of acids and alkalis, biological treatment using microorganisms, and physical treatment Can also be used.

  The preferred melt flow index (MFI) of the aliphatic polyester resin (A) is usually 0.1 g / 10 min or more, usually 100 g / 10 min or less, preferably 50 g when measured at 190 ° C. and 2.16 kg. / 10 minutes or less, more preferably 30 g / 10 minutes or less. Here, MFI is a value at 190 ° C. and a load of 2.16 kg, measured according to the thermoplastic flow test method defined in JIS K7210.

  The preferred weight average molecular weight of the aliphatic polyester resin (A) is usually 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more, and usually 1,000,000 or less, preferably 800,000 or less, more preferably 600,000 or less. If it is out of this range, it tends to be difficult to perform various molding processes.

  The preferred melting point of the aliphatic polyester resin (A) is usually 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and usually 150 ° C. or lower, preferably 140 ° C. or lower, more preferably 120 ° C. It is below ℃. The melting point can be measured, for example, by differential scanning calorimetry (DSC). Specifically, using a DSC7 differential scanning calorimeter manufactured by Perkin Elmer, Inc., the sample was heated from room temperature to 230 ° C. under the condition of 80 ° C./min, held at the same temperature for 10 minutes, and then −10 The temperature is lowered to 40 ° C. at a temperature of 40 ° C./minute, held at the same temperature for 3 minutes, and then the melting point can be the peak temperature when melted under a temperature rising condition of 10 ° C./minute.

  When the aliphatic polyester-based resin (A) that is the raw material of the surface layer contains a large amount of low molecular weight oligomer, when this is molded into a biodegradable resin laminate, the low molecular weight oligomer contained on the laminate surface with time after molding. It may spout and damage the appearance. Therefore, the upper limit of the content of the low molecular weight oligomer in the aliphatic polyester resin (A) as the raw material for the surface layer is usually 10,000 ppm or less, preferably 90000 ppm or less, more preferably 8000 ppm or less on a mass basis. Is preferred. If it exceeds 10000 ppm, the tendency of deterioration of appearance due to oligomer ejection becomes remarkable, it is scattered in the atmosphere at the time of molding and the respiratory system is stimulated, or the moldability is deteriorated by ejection of the oligomer on the surface of the laminate. Tend. On the other hand, the lower limit is usually 1000 ppm or more, preferably 2000 ppm or more, more preferably 3000 ppm or more. In order to make it less than 1000 ppm, it is necessary to remove low molecular weight oligomers by using various means. For example, in the case of solvent washing, there are problems such as mixing of solvent into the resin, increased cost for washing, and deterioration of the resin. become.

  In particular, when the diol unit represented by the above formula (1) and the dicarboxylic acid unit represented by the formula (2) are used as the raw material of the aliphatic polyester resin (A), the cyclic structure formed by these structural units is used. Due to the low molecular weight oligomer, the tendency of appearance deterioration becomes more remarkable. The cyclic structure here is, for example, when the diol component giving the diol unit of the above formula (1) is 1,4-butanediol and the dicarboxylic acid component giving the dicarboxylic acid unit of the above formula (2) is succinic acid. It refers to a structure represented by the following formula (3) consisting of two 1,4-butanediol units (BG) and two succinic acid (SA) units.

  In the biodegradable resin of the present invention, it is essential that the aliphatic polyester resin (A) as the surface layer has a low molecular weight oligomer content of 1000 to 10,000 ppm. By using the aliphatic aromatic polyester resin (B) described later as an intermediate layer in combination with the aliphatic polyester resin (A) having an oligomer content in such a range, oligomer ejection is suppressed and appearance deterioration is improved. can do.

  When the surface layer is composed only of the aliphatic polyester-based resin (A), the amount of the low molecular weight oligomer contained in the raw material aliphatic polyester-based resin (A) is determined based on the aliphatic polyester-based surface layer of the biodegradable resin laminate. It can be considered that it is the quantity of the low molecular weight oligomer which resin (A) contains. Therefore, as a simple method for bringing the amount of the low molecular weight oligomer contained in the aliphatic polyester resin (A) in the surface layer within the above specified range, a commercially available fat having a content of the low molecular weight oligomer within the above specified range. A group polyester-based resin (A) may be used.

  Examples of the aliphatic polyester-based resin (A) that can be obtained as a commercial product include GSPla (registered trademark) manufactured by Mitsubishi Chemical Corporation, Bionore (registered trademark) manufactured by Showa Polymer Co., Ltd., and Lacia manufactured by Mitsui Chemicals, Inc. Registered trademark), Daicel Chemical Industries, Ltd. Cell Green (registered trademark), and the like. When a commercially available product is used and the amount of oligomer is outside the numerical range of the present invention, it is used after it is within a predetermined oligomer amount range using a known technique such as washing the pellet.

  The surface layer of the biodegradable resin laminate of the present invention may also contain a resin other than the aliphatic polyester resin (A) as long as the effects of the present invention are not significantly impaired. Examples of the resin other than the aliphatic polyester resin (A) include ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, polypropylene, and ethylene-propylene. Thermoplastic resins such as rubber, polyvinyl acetate, polybutene, polycarbonate, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyether such as polyethylene oxide, etc. And natural resins such as rosin, dammar, and guttaberca. These resins may be used alone or in combination of two or more in any combination and ratio as long as the effects of the present invention are not significantly impaired.

  However, when a resin other than the aliphatic polyester resin (A) is mixed, the amount to be mixed is usually 20% by mass or less, preferably 15% by mass or less, based on the aliphatic polyester resin (A). Preferably it is 10 mass% or less. Beyond this range, biodegradability tends to decrease. In addition, when using 2 or more types of resin other than an aliphatic polyester-type resin (A) together, it is preferable that the sum total of those usage amount satisfy | fills the said range.

<Intermediate layer: Aliphatic aromatic polyester resin (B)>
As the aliphatic aromatic polyester-based resin (B) constituting the intermediate layer, at least a part of the structural units in the structure of the above-described aliphatic polyester-based resin (A) is a structural unit having an aromatic (hereinafter referred to as appropriate). Examples thereof include polyester resins having “aromatic units”.

  Examples of the aromatic unit include an aromatic diol unit having an aromatic hydrocarbon group which may have a substituent, and an aromatic dicarboxylic acid unit having an aromatic hydrocarbon group which may have a substituent. And an aromatic oxycarboxylic acid unit having an aromatic hydrocarbon group which may have a substituent. The aromatic hydrocarbon group may be a single ring, or may be one in which a plurality of rings are bonded to each other or condensed. Specific examples of the aromatic hydrocarbon group include 1,2-phenyl group, 1,3-phenyl group, 1,4-phenyl group, dinaphthyl group, diphenyl group and the like.

  Specific examples of the aromatic dicarboxylic acid component that gives an aromatic dicarboxylic acid unit include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and the like. Of these, terephthalic acid is preferred.

  The aromatic dicarboxylic acid component may be a derivative of an aromatic dicarboxylic acid compound. For example, the derivatives of the aromatic dicarboxylic acid components exemplified above are preferable, and among them, lower alkyl esters having 1 to 4 carbon atoms, acid anhydrides, and the like can be given. Specific examples of the derivatives of the aromatic dicarboxylic acid compound include the above exemplified aromatic dicarboxylic acid components such as methyl ester, ethyl ester, propyl ester and butyl ester, lower alkyl esters; succinic anhydride and the like. Cyclic acid anhydrides of a group dicarboxylic acid component; and the like. Of these, dimethyl terephthalate is preferable.

  Specific examples of the aromatic diol component that gives an aromatic diol unit include, for example, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2-bis ( 4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid and the like. The aromatic diol component may be a derivative of an aromatic diol compound. Further, it may be a compound having a structure in which a plurality of aliphatic diol compounds and / or aromatic diol compounds are dehydrated and condensed with each other.

  Specific examples of the aromatic oxycarboxylic acid component that gives an aromatic oxycarboxylic acid unit include p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid. The aromatic oxycarboxylic acid component may be a derivative of an aromatic oxycarboxylic acid compound. Further, it may be a compound (oligomer) having a structure in which a plurality of aliphatic oxycarboxylic acid compounds and / or aromatic oxycarboxylic acid compounds are dehydrated and condensed with each other. That is, an oligomer may be used as a raw material.

  When an optical isomer exists in the aromatic component that gives these aromatic units, any of D-form, L-form, and racemate may be used. Moreover, as an aromatic component, if an aromatic unit can be given to an aliphatic polyester-type resin (A), it will not be limited to said example. Furthermore, an aromatic component may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  As the aliphatic aromatic polyester resin (B) used in the biodegradable resin laminate of the present invention, it is preferable to use an aromatic dicarboxylic acid component as a component that gives an aromatic unit. The content of the acid unit is preferably 10 mol% or more and 80 mol% or less based on the total amount of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit (100 mol%). Further, terephthalic acid is preferably used as the aromatic dicarboxylic acid component, and the aliphatic aromatic polyester resin (B) is preferably a polybutylene terephthalate adipate and / or a polybutylene terephthalate succinate resin.

  The production method of the aliphatic aromatic polyester-based resin (B) is not limited as long as the effects of the present invention are not significantly impaired, and can be produced by any known method. For example, a melt polymerization method in which an esterification reaction and / or a transesterification reaction between a dicarboxylic acid component and a diol component is performed, and then a polycondensation reaction is performed under reduced pressure, a solution heating dehydration condensation method using an organic solvent, etc. Can be manufactured by. Among these, from the viewpoint of economy and simplicity of the production process, a melt polymerization method carried out in the absence of a solvent is preferable.

  Further, the aliphatic aromatic polyester resin (B) may be derived from biomass resources in the same manner as the aliphatic polyester resin (A). The kind of biomass resource and its manufacturing method can also illustrate the same thing as an aliphatic polyester-type resin (A).

  The preferred melt flow index (MFI) of the aliphatic aromatic polyester resin (B) is usually 0.1 g / 10 min or more, and usually 100 g / 10 min or less, preferably 190 g, when measured at 190 ° C. and 2.16 kg. Is 50 g / 10 min or less, more preferably 30 g / 10 min or less. Here, MFI is a value at 190 ° C. and a load of 2.16 kg, measured according to the thermoplastic flow test method defined in JIS K7210.

  The preferred weight average molecular weight of the aliphatic aromatic polyester resin (B) is usually 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more, and usually 1,000,000 or less. Preferably it is 800,000 or less, More preferably, it is 600,000 or less. If it is out of this range, it tends to be difficult to perform various molding processes.

  The preferred melting point of the aliphatic aromatic polyester resin (B) is usually 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and usually 150 ° C. or lower, preferably 140 ° C. or lower, more preferably. Is 120 ° C. or lower. The melting point can be measured, for example, by differential scanning calorimetry (DSC). Specifically, using a DSC7 differential scanning calorimeter manufactured by Perkin Elmer, Inc., the sample was heated from room temperature to 230 ° C. under the condition of 80 ° C./min, held at the same temperature for 10 minutes, and then −10 The temperature is lowered to 40 ° C. at a temperature of 40 ° C./minute, held at the same temperature for 3 minutes, and then the melting point can be the peak temperature when melted under a temperature rising condition of 10 ° C./minute.

  The aliphatic aromatic polyester-based resin (B) can also be obtained as a commercial product, for example, EI DuPont de Nemours & Co. Biomax (registered trademark), BASF Ecoflex (registered trademark), etc. Is mentioned.

  Similarly to the surface layer, the intermediate layer of the biodegradable resin laminate of the present invention may also contain a resin other than the aliphatic aromatic polyester resin (B) as long as the effects of the present invention are not significantly impaired. Examples of the resin other than the aliphatic aromatic polyester resin (B) include the same resins as those other than the aliphatic polyester resin (A) that may be added to the surface layer. These resins may be used alone or in combination of two or more in any combination and ratio as long as the effects of the present invention are not significantly impaired.

  When a resin other than the aliphatic aromatic polyester resin (B) is mixed, the amount to be mixed is usually 20% by mass or less, preferably 15% by mass or less, based on the aliphatic aromatic polyester resin (B). More preferably, it is 10 mass% or less. Beyond this range, biodegradability tends to decrease. In addition, when using 2 or more types of resin other than an aliphatic aromatic polyester-type resin (B) together, it is preferable that the total of those usage-amounts satisfy | fill the said range.

<Additives>
Various conventionally well-known additives can be mix | blended with the aliphatic polyester-type resin (A) and aliphatic-aromatic-polyester-type resin (B) used as each layer of the biodegradable resin laminated body of this invention. Examples of the additive include inorganic fillers, heat stabilizers, light resistance agents, ultraviolet absorbers, compatibilizers, antistatic agents, and starch. Each of these may be used alone or in combination of two or more. Moreover, an additive can be mixed with arbitrary forms. For example, it may be mixed as a solid, as a solution dissolved in a solvent, or as a slurry dispersed in a solvent.

  Examples of the inorganic filler include natural minerals, potassium titanate, calcium carbonate, basic magnesium sulfate, sepiolite, zonotlite, aluminum borate, acicular magnesium hydroxide, and other acicular fillers such as whiskers; glass fiber, carbon Fibrous inorganic fillers such as fiber, silica fiber, silica / alumina fiber, zirconia, rock wool; talc, mica, graphite, BN (hexagonal crystal), MIO (plate iron oxide), plate calcium carbonate, plate water Plate-like particles such as aluminum oxide, glass flakes and various metal foils; spherical calcium carbonate, silica, clay, various beads and the like. Of these, fillers such as talc and mica are preferable.

  Examples of the heat stabilizer include dibutylhydroxytoluene (BHT; 2,6-di-t-butyl-4-methylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), pentaerythritol tetrakis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″ -(Mesitylene-2,4,6-triyl) tri-p-cresol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [(4 -Tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-to (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [[3,5- Bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, bis (2,2′-dihydroxy-3,3′-di-tert-butyl-5,5′-dimethylphenyl) ethane, N , N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide and other hindered phenol thermal stabilizers; tridecyl phosphite, diphenyl decyl phosphite , Tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, bis [2,4- (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid stabilizers such as phosphorous acid, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite; 3-hydroxy Lactone-based thermal stabilizers such as -5,7-di-tert-butyl-furan-2-one and xylene reactive organisms; sulfur-based antioxidants such as dilauryl thiodipropionate and distearyl thiodipropionate And the like.

  The amount of the heat stabilizer to be mixed is usually 100 ppm or more, preferably 200 ppm or more on a mass basis with respect to the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B). It is not more than part by mass, preferably not more than 1 part by mass, more preferably not more than 0.5 part by mass. Below this range, the effect of the heat stabilizer tends to be small. On the other hand, if it exceeds this range, the manufacturing cost tends to be high, and the bleedout of the thermal stabilizer may occur.

  Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester decaneate, a reaction product of 1,1-dimethylethyl hydroperoxide and octane, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (1,2,2 , 6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate , 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl) -4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, poly [[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine -2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] Examples include hindered amine stabilizers. The light stabilizer is preferably used in combination with an ultraviolet absorber, and a combination of a hindered amine stabilizer and an ultraviolet absorber is effective.

  The amount of the light-resistant agent to be mixed is usually 100 ppm or more, preferably 200 ppm or more, and usually 5 masses based on mass with respect to the aliphatic polyester resin (A) or aliphatic aromatic polyester resin (B). Part or less, preferably 1 part by weight or less, more preferably 0.5 part by weight or less. Below this range, the effect of the light resisting agent tends to be small. Moreover, when it exceeds this range, the manufacturing cost tends to be high, the heat resistance of the biodegradable resin laminate is inferior, and the light-proofing agent tends to bleed out.

  As the ultraviolet absorber, 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol, 2- (4,6-diphenyl-1,3,5) -Triazin-2-yl) -5-[(hexyl) oxy] phenol and the like. As the ultraviolet absorber, it is particularly preferable to use two or more different types of ultraviolet absorbers in combination.

  The amount of the ultraviolet absorber to be mixed is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually on a mass basis with respect to the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B). It is 100 ppm or more, preferably 200 ppm or more, and usually 5% by mass or less, preferably 2% by mass or less, more preferably 0.5% by mass or less. Below this range, the effect of the ultraviolet absorber tends to decrease. Moreover, when it exceeds this range, the manufacturing cost tends to be too high, the heat resistance of the resin is inferior, or the ultraviolet absorber bleeds out.

  As a compatibilizer, an ester group, a carboxylic acid anhydride, an amide group, an ether group, a cyano group, an unsaturated hydrocarbon group, an epoxy group, an acrylic group, a methacrylic group, an aromatic group are added to the terminal or main chain of the aliphatic polyester. The compound etc. which reacted with the hydrocarbon group etc. are mentioned.

  Examples of the compatibilizer include aliphatic polyester and aromatic polyester resin such as polyolefin resin, polyurethane resin, polycarbonate resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyarylate, and liquid crystal polymer; Vinyl resin; SEBS (polystyrene-block-poly (ethylene-co-butylene) -block-polystyrene), SEPS (polystyrene-block-poly (ethylene-co-propylene) -block-polystyrene), styrene resins such as polystyrene; Nylon 6, nylon 6-6, nylon 6-10, nylon 9, nylon 11, nylon 13 nylon 4, nylon 4-6, nylon 5-6, nylon 12, nylon 10-12, Polyamide resins such as ramids; Riacetal resins; Acrylic resins such as polymethyl methacrylate, polymethacrylic acid ester, polyacrylic acid ester; Polyethylene glycol, polypropylene glycol, poly 1,3-propanediol, polytetramethylene glycol, modified polyphenylene Examples thereof include polyether resins such as ether; polyphenylene sulfide resins; polyether ketone resins; polyether ether ketone resins; Moreover, the graft copolymer with the above-mentioned resin, a block copolymer, a multiblock copolymer, a random copolymer, etc. are mentioned.

  Further, in addition to the above-mentioned copolymer, the compatibilizer includes a compound containing both the structures of different resins to be blended in the same molecule. Also, polyurethane resin, polycarbonate resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, SEBS, SEPS, polystyrene, nylon 6, nylon 6-6, nylon 12, polyacetal resin, polymethyl methacrylate, polymethacrylate, polyacryl Reacts with hydroxyl group, carboxyl group, ester group, alkyl group, alkylene group at the end or side chain of polymer molecule of acrylic resin such as acid ester, polyethylene glycol, polypropylene glycol, poly 1,3-propanediol, polytetramethylene glycol Examples thereof include a polymer having a possible functional group.

  It is preferable to use the compatibilizing agent particularly when the surface layer or the intermediate layer contains two or more kinds of resins. The amount of the compatibilizer to be mixed is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 0.01 with respect to the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B). It is not less than part by mass, preferably not less than 0.1 part by mass, more preferably not less than 1 part by mass, and usually not more than 50 parts by mass, preferably not more than 30 parts by mass, more preferably not more than 10 parts by mass. Above this range, manufacturing costs tend to be high. Moreover, when it is less than this range, the effect of the compatibilizer tends to be small.

  Any antistatic agent can be used as long as the effects of the present invention are not significantly impaired. As a specific example, a surfactant type nonionic, cationic or anionic type is preferable.

  Nonionic antistatic agents include glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyldiethanolamine, hydroxyalkyl monoethanolamine, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester alkyldiethanol Amides etc. are mentioned. Of these, alkyldiethanolamines are preferred.

  Examples of the cationic antistatic agent include tetraalkylammonium salts and trialkylbenzylammonium salts.

  Examples of the anionic antistatic agent include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates. Of these, alkylbenzene sulfonate is preferred because of its good kneadability with the resin and high antistatic effect.

  The amount of the antistatic agent used is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.5% by mass based on the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B). As mentioned above, Preferably it is 1 mass% or more, and is 5 mass% or less normally, Preferably it is 3 mass% or less. When the above range is exceeded, the fusibility between the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B) tends to decrease. Furthermore, surface stickiness of the biodegradable resin laminate occurs, and the product value tends to decrease. On the other hand, if it is below the above range, the effect of improving the antistatic property tends to be reduced.

  Specific examples of the starch include corn starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, pea starch, etc. preferable. Further, it may be a modified product of starch, and “modification” includes all modification methods such as chemical, physical and biological. Addition of starch can improve the mechanical properties of the biodegradable resin laminate.

  The preferable addition amount of starch represents the mass part of the aliphatic polyester resin (A) by (X), the mass part of the aromatic aliphatic polyester resin (B) by (Y), and the mass part of the starch. In terms of (Z), (Z) / [(X) + (Y)] = 0.05 to 0.50. The lower limit of the mass ratio is preferably 0.1, more preferably 0.20. The upper limit is preferably 0.45, more preferably 0.40, and particularly preferably 0.30. If the starch content is too low, the effect of improving the physical properties by starch will not be fully manifested, and the merit of lowering the raw material cost by adding starch will be reduced, while if the starch content is too high, Property, hydrolysis resistance, flexibility and the like may be impaired.

  Furthermore, as additives, lubricants, antiblocking agents, mold release agents, antifogging agents, crystal nucleating agents, colorants, flame retardants, and the like may be added. Any of these can be used as long as the effects of the present invention are not significantly impaired. Moreover, these may be used individually by 1 type, respectively, and 2 or more types may be mixed and used for them. However, the above-mentioned additives are usually 100 ppm or more, preferably 200 ppm or more, and 5 mass by mass based on the mass of the aliphatic polyester-based resin (A) or the aliphatic aromatic polyester-based resin (B). Part or less, preferably 1 part by weight or less, more preferably 0.5 part by weight or less. When the content is below this range, the effect of addition tends to be small, while when the content is above this range, the production cost tends to be high, and the heat resistance of the aliphatic polyester resin (A) and the aliphatic aromatic polyester resin (B). There is a tendency for the properties to decrease and the additive to bleed out.

<Biodegradable resin laminate and manufacturing method thereof>
The biodegradable resin laminate of the present invention comprises a pair of surface layers composed of an aliphatic polyester resin (A) having a low molecular weight oligomer content of 1000 to 10,000 ppm, and an aliphatic aromatic polyester provided between the surface layers. It is a laminated body which has an intermediate | middle layer which consists of resin (B).

  The laminate of the present invention is a constitution in which the order of lamination of aliphatic polyester resin (A) / aliphatic aromatic polyester resin (B) / aliphatic polyester resin (A) is essential. Unless the effect is significantly impaired, a layer other than the aliphatic polyester resin (A) or the aliphatic aromatic polyester resin (B) may be laminated between the layers. In addition, the aliphatic polyester resin (A) in the surface layer does not necessarily need to be the outermost surface layer, and other layers may be laminated as the outer layer of the aliphatic polyester resin (A).

  When laminating other resins, the resin constituting the layer is ultra low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene-propylene. Thermoplastic resins such as rubber, polyvinyl acetate, polybutene, polycarbonate, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyether such as polyethylene oxide, etc. Examples thereof include natural resins such as rosin, dammar, and Guttavelka. In addition, paper or a metal film may be laminated.

  Preferably, in the biodegradable resin laminate of the present invention, the outermost surface layer is preferably an aliphatic polyester-based resin (A) layer, more preferably aliphatic polyester-based resin (A) / aliphatic aroma. This is a three-layer structure of an aliphatic polyester resin (B) / aliphatic polyester resin (A). Further, the two layers of the aliphatic polyester resin (A) constituting the pair of surface layers may be different from each other, but preferably the same aliphatic polyester resin (A) is used for the two layers.

  The thickness of the three layers of the aliphatic polyester resin (A) / aliphatic aromatic polyester resin (B) / aliphatic polyester resin (A) constituting the biodegradable resin laminate is the surface layer / intermediate layer. The ratio of the / surface layer is usually in the range between 1/10/1 to 10/1/10, preferably 1/8/1 to 8/1/8. When the surface layer becomes thicker, the elastic modulus increases and the so-called film becomes stiff, so that the thickness can be reduced practically, but resistance to large deformation such as tear strength tends to be weakened. On the other hand, when the surface layer is thin, resistance to large deformation such as tear strength is exhibited, but the elastic modulus is low, and it is necessary to increase the thickness of the film, resulting in a cost problem. Further, when considering a film having a normal thickness (about 50 μm), when the ratio of the surface layer / intermediate layer / surface layer is less than 1/10/1, the thickness of the outer layer becomes about 4 μm or less, and multilayer molding It approaches the limit of the thinness of the layer that can be formed by machine.

  The thickness of the biodegradable resin laminate is arbitrary depending on the application, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less.

  The manufacturing method of the laminated body of this invention does not have a restriction | limiting, unless the effect of this invention is impaired remarkably, It can manufacture by any well-known method. As a method for producing a laminate, any known method used in a method for producing general-purpose plastics can be used. As specific examples, an extrusion molding method, a calendar molding method, a compression molding method, a cast molding method, a T-die method, an inflation method, a calendar roll method, and the like can be used. Among them, the extrusion method, the T-die method, the inflation method, and the calender roll method are preferable, and the inflation method is particularly preferable. Examples of the cooling method of the T-die method include a method of constricting with two or more cooling rolls, a method of pressing against a roll with an air knife, and a method of cooling by contacting a metal belt on one or both sides.

  The laminate of the present invention can be used for various applications by further molding. Specific examples include films, laminate films, sheets, plates, stretched sheets, containers, trays, porous films, synthetic papers, blow bottles, and foams.

  When processing the laminated body of this invention into three-dimensional shapes, such as a container and a tray, thermoforming is used preferably. In general, thermoforming means heat-softening a plastic sheet and pressing it against a desired mold, eliminating air in the gap between the mold and the material, and forming it in close contact with the mold by atmospheric pressure, or above atmospheric pressure This is a general term for compressed air or vacuum / compressed air forming using vacuum together.

  As a specific method of thermoforming, a method of forming into a mold shape using vacuum or compressed air and, if necessary, further using a plug (specifically, straight method, drape method, air slip method) Snapback method, plug assist method, plug assist reverse draw molding method, multi-mold molding method, etc.), solid phase press molding method, stamping molding method and the like. Various conditions such as the temperature of thermoforming, the degree of vacuum, the pressure of compressed air, or the forming speed are appropriately set depending on the plug shape, the die shape, or the properties of the raw material sheet.

  In addition, for molded products such as sheets and containers obtained from these biodegradable resin laminates, chemical functions, electrical functions, magnetic functions, mechanical functions, friction / abrasion / lubrication functions, optical functions, heat For the purpose of imparting surface functions such as mechanical functions and biocompatibility, it is possible to apply various secondary processings. Examples of secondary processing include embossing, painting, adhesion, printing, metalizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, Coating, etc.).

  The laminate of the present invention has an excellent tensile modulus according to JIS K7127 of usually 100 MPa or more, preferably 200 MPa or more, and Elmendorf tear strength according to JIS K7128 is usually 3 N / mm or more, preferably 6 N / mm or more. Has tensile modulus and tear strength. Moreover, since oligomer precipitation from the surface of the laminate is suppressed, it is possible to obtain a molded product in which surface whitening and stickiness are suppressed, safety is ensured, and the like. For this reason, the laminated body of the present invention and its molded product can be suitably used for a wide range of applications including various bag products such as garbage bags and shopping bags, as well as containers and packaging that come into contact with food.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example at all unless the summary is exceeded. In addition, the measuring method of the evaluation item employ | adopted in the following examples is as follows.

<Moldability>
The state of the film after inflation molding was evaluated according to the following criteria.
Good (O): After inflation molding, the mouth of the tubular film can be easily opened.
Defect (x): After inflation molding, the inside of the tubular film is fused and the mouth cannot be opened.

<Low molecular weight oligomer surface precipitation test>
The produced film was stored for 1 month under the conditions of 23 ° C. and 50% RH, and then the appearance of the film was visually observed and evaluated according to the following criteria.
Good ((circle)): The white deposit is not confirmed visually on the surface of a film, but it is transparent.
Defect (x): A white precipitate can be visually confirmed on the surface of the film, and the film is cloudy.

<Measurement method of tear strength>
Elmendorf tear strength was measured in accordance with JIS K7128.

<Measurement method of tensile modulus>
Based on JIS K7127, the tensile elasticity modulus was measured with Shimadzu Corporation precision universal testing machine Autograph AG-2000.

Example 1
GSPla (grade name: AZ91TN, low molecular weight oligomer (here, cyclic oligomer amount) 8000 ppm) manufactured by Mitsubishi Chemical Co., Ltd. is used as the aliphatic polyester resin (A) on the upper and lower surface layers, and the aromatic aliphatic polyester system is used as the intermediate layer. As the resin (B), Ecoflex manufactured by BASF was used and melt extruded at 130 ° C from an annular die with a diameter of 106 mm and a lip width of 1.8 mm mounted on an extruder with a diameter of 40 mm. Blow ratio = 3, take-up speed Co-extrusion air-cooled inflation molding was performed at 20 m / min to obtain a tube-shaped two-type three-layer film having a thickness of 50 μm (surface layer / intermediate layer / surface layer = 12.5 μm / 25 μm / 12.5 μm). The three-layer laminated film produced in this way was stored for 2 days under the conditions of 23 ° C. and 50% RH and subjected to various measurements. The results are shown in Table 1.

(Example 2)
It carried out similarly to Example 1 except having changed the thickness of the surface layer and the intermediate | middle layer. The results are shown in Table 1.

(Comparative Example 1)
Manufacture of the following multilayer film which changed the layer order with Example 1 was tried with the following method. BASF Ecoflex is used as the aromatic aliphatic polyester resin (B) for the surface layer, and GSPla (grade name: AZ91TN, low molecular weight oligomer (made by Mitsubishi Chemical Corporation) is used as the aliphatic polyester resin (A) for the intermediate layer. Here, the amount of cyclic oligomer (8000 ppm) was melt-extruded at 130 ° C. from a circular die having a diameter of 106 mm and a lip width of 1.8 mm, each mounted on an extruder having a diameter of 40 mm, so that the blow ratio = 3 and the take-up speed 20 m / min. Then, co-extrusion air-cooled inflation molding was performed to obtain a tube-shaped two-type three-layer film having a thickness of 50 μm (surface layer / intermediate layer / surface layer = 12.5 μm / 25 μm / 12.5 μm). The inner side was completely fused, and the desired two-kind three-layer film could not be obtained. Therefore, physical property measurement was impossible.

(Comparative Example 2)
Both the surface layer and the intermediate layer are aliphatic polyester resins (A), GSPla (grade name: AZ91TN, low molecular weight oligomer (here, cyclic oligomer amount) 8000 ppm) manufactured by Mitsubishi Chemical Corporation, and the extrusion temperature is set to the surface layer. Except that both the intermediate layer and the intermediate layer were set to 125 ° C., inflation molding was performed in the same manner as in Example 1 to obtain a tube-type 1-type 3-layer film (substantially 1-type 1-layer film) having a thickness of 50 μm. The results are shown in Table 1.

  As shown in Table 1, all the films that are the biodegradable resin laminates of the present invention have good moldability, and films having excellent tensile elastic modulus and tear strength were obtained. Also, no oligomer precipitation was observed. On the other hand, in the film of Comparative Example 2, oligomer precipitation was confirmed.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The biodegradable resin laminate and the method for producing the same can also be modified as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. It should be understood as encompassed by the scope.

Claims (5)

A biodegradable resin laminate comprising at least three layers of a pair of surface layers forming a front surface portion and a back surface portion and an intermediate layer provided between the pair of surface layers, each of the pair of surface layers being aliphatic It is made of a polyester resin (A), the intermediate layer is made of an aliphatic aromatic polyester resin (B), and the amount of the low molecular weight oligomer in the aliphatic polyester resin (A) Polyester-based resin (A) Biodegradable resin laminate characterized by being 1000 to 10,000 ppm based on mass. The biodegradable resin laminate according to claim 1, wherein the aliphatic polyester resin (A) comprises an aliphatic diol unit and an aliphatic dicarboxylic acid unit as constituent units. The aliphatic polyester resin (A) is a polybutylene succinate resin and / or a polybutylene succinate adipate resin, and the aliphatic aromatic polyester resin (B) is a polybutylene adipate terephthalate resin. The biodegradable resin laminate according to claim 1 or 2, wherein the biodegradable resin laminate is provided. The ratio of the surface layer / intermediate layer / surface layer thickness of the three layers of the biodegradable resin laminate is in the range of 1/10/1 to 10/1/10. 4. The biodegradable resin laminate according to any one of 3 above. A pair of surface layers consisting of an aliphatic polyester resin (A), wherein the amount of low molecular weight oligomers in the aliphatic polyester resin (A) is 1000 to 10,000 ppm based on the mass of the aliphatic polyester resin (A); A method for producing a biodegradable resin laminate comprising at least three intermediate layers made of an aliphatic aromatic polyester resin (B) provided between the pair of surface layers, the biodegradable resin laminate The biodegradable resin laminate is produced by inflation molding so that the ratio of the thickness of the surface layer / intermediate layer / surface layer of the three layers is 1/10/1 to 10/10/10 Method.