JP2005036179A - Aliphatic polyester resin composition - Google Patents

Abstract

An aliphatic polyester resin composition that is excellent in moldability, flexibility, and heat resistance and exhibits excellent mechanical properties in various molding processes.
(A) Aliphatic polyester resin: 50 parts by weight or more and 100 parts by weight or less (B) Polylactic acid: Resin component comprising 0 part by weight or more and 50 parts by weight or less (however, (A) and (B) And (C) plasticizer: from 1 part by weight to 80 parts by weight with respect to 100 parts by weight of the resin component, and a flexural modulus of 500 MPa or less, An aliphatic polyester resin composition having a hardness of 65 or less and a melt tension of 2 g or more.

Description

  The present invention relates to an aliphatic polyester resin composition. More specifically, the present invention relates to an aliphatic polyester resin composition that is obtained by melt-kneading an aliphatic polyester resin and a plasticizer and is excellent in mechanical strength, low bleedability of the plasticizer, and the like.

  Conventionally, a high molecular weight polyester resin having a number average molecular weight of about 10,000 or more, which is used as a molding raw material for films, fibers and other molded articles, is generally an aromatic polyester resin, for example, PET (synthesized from terephthalic acid and ethylene glycol). Polyethylene terephthalate), or aromatic polyester resins such as PBT (polybutylene terephthalate) synthesized from terephthalic acid and 1,4-butanediol.

  These products are disposed of by incineration or landfill when they are discarded after use, but in the case of incineration, the cost for incineration increases. On the other hand, in the case of landfill, the shortage of landfill sites in recent years has become a social problem. This is because the aromatic polyester resin is hardly decomposed in the natural environment, and therefore remains in the ground semipermanently even after landfill disposal.

  On the other hand, aliphatic polyester resins synthesized from polylactic acid, aliphatic polyhydric alcohols, and aliphatic polycarboxylic acids have been developed as biodegradable polymers in recent years. These biodegradable resins are biologically decomposed by microorganisms in the natural environment such as soil, and finally completely decomposed into carbon dioxide and water, thus solving the above-mentioned problems in the disposal process. be able to.

  However, since polylactic acid has high rigidity, it is unsuitable as a forming raw material for films, sheets and the like.

  In addition, aliphatic polyester resins have been difficult to put into practical use for the following reasons. That is, the melting point of the aliphatic polyester resin is relatively low, and it is difficult to obtain an aliphatic polyester resin having a number average molecular weight of 15,000 or more by a commonly known polycondensation reaction. A practically sufficient strength cannot be obtained with a copolymer having a number average molecular weight of about 10,000. Moreover, although the conventional aliphatic polyester resin is flexible and has sufficient elongation as compared with polylactic acid, it has a high strength such as hardness and elastic modulus depending on the use and is too hard. Furthermore, since these aliphatic polyester resins have low melt tension, they are not suitable for molding methods such as inflation molding, lamination molding, and vacuum and pressure molding using sheets, and may cause tearing and cracking during melt molding. There is a problem that the molding stable region is narrow.

  As a method for softening a resin, a method for adding a plasticizer is widely known. For example, by using a polylactic acid resin composition in which a predetermined amount of plasticizer is blended with a resin component consisting of 90 to 50% by weight of polylactic acid and 10 to 50% by weight of an aliphatic polyester having a melting point of 80 to 250 ° C., It is disclosed that a film or sheet excellent in flexibility can be obtained (Patent Document 1). However, the film obtained by this method has an elastic modulus that is an index of flexibility of 0.6 to 1.0 GPa, and is not sufficiently flexible. In addition, Patent Document 1 does not specifically describe the melt flow ratio and melt tension, which are indexes of moldability such as inflation molding, blow molding, and vacuum molding. Generally, polylactic acid and aliphatic compounds having low melt tension are used. Melt tension cannot be improved by simply mixing polyester with a plasticizer.

  Moreover, the method of improving a softness | flexibility and heat resistance is disclosed by adding the reaction product of glycerol and carboxylic acid to an aliphatic polyester as a plasticizer (patent document 2). However, even by this method, the elastic modulus does not sufficiently decrease, and the flexibility is not sufficient.

Furthermore, a method for improving the melt tension with a low elastic modulus by finely crosslinking a blend of polylactic acid and aliphatic polyester with an organic peroxide is disclosed (Patent Document 3). However, according to this method, although the melt tension is improved, the elastic modulus is around 1000 MPa, and it is difficult to say that the hardness and flexibility are sufficient.
JP-A-11-116788 JP 2000-302956 A JP 2001-26658 A

  The present invention can be applied to various fields such as injection molding, film, sheet, vacuum / pneumatic molding fiber by sheet molding, etc., biodegradability excellent in moldability, flexibility and heat resistance, that is, low bleedability of plasticizer. An object of the present invention is to provide an aliphatic polyester resin composition.

The aliphatic polyester resin composition of the present invention is
(A) Aliphatic polyester resin 50 parts by weight or more and 100 parts by weight or less,
And (B) a resin component comprising 0 to 50 parts by weight of polylactic acid (provided that the total of (A) and (B) is 100 parts by weight);
(C) Plasticizer A composition obtained by melt-kneading 1 to 80 parts by weight with respect to 100 parts by weight of the resin component, wherein the flexural modulus is 500 MPa or less, the hardness is 65 or less, and the melt tension is 2 g. It is the above.

  That is, the present inventors have molded a resin composition obtained by melt-mixing an aliphatic polyester resin (A) and, if necessary, polylactic acid (B) and a plasticizer (C) at a predetermined ratio. The present invention has been found out that it is excellent in all of properties, flexibility and heat resistance.

  In the present invention, “aliphatic polyester” is “aliphatic polyester” in a broad sense including “alicyclic polyester”.

In the present invention, the aliphatic polyester resin (A) has an aliphatic polyester portion,
(A) an aliphatic dicarboxylic acid unit,
(B) Aliphatic diol unit The aliphatic dicarboxylic acid unit (a) is 98 mol to 102 mol with respect to 100 mol,
And (c) an aliphatic hydroxycarboxylic acid unit (a) preferably composed of 0 to 60 moles per 100 moles of the aliphatic dicarboxylic acid unit (a), and (d) A polyester polyether copolymer having a polyether moiety represented by the following general formula (1) is preferable. In this polyester polyether copolymer, the proportion of the polyether portion (b) represented by the following general formula (1) is preferably 1% by weight or more and 90% by weight or less.

（一般式（１）中、Ｒは水素又は炭素数１以上１０以下のアルキル基を表す。ｍは１以上１０以下の整数を表し、ｎは１以上１０００以下の整数を表す。）

(In general formula (1), R represents hydrogen or an alkyl group having 1 to 10 carbon atoms. M represents an integer of 1 to 10 and n represents an integer of 1 to 1000.)

  The aliphatic polyester resin composition of the present invention is a compound further having 0.001 to 5 parts by weight of an organic peroxide (D) and, if necessary, two or more vinyl groups with respect to 100 parts by weight of the resin component. (E) It may contain 0.001-5 weight part, and melt tension can be secured by blending this (D) component or (D) component and (E) component.

  The aliphatic polyester resin composition of the present invention has a flexural modulus of 500 MPa or less, a hardness of 65 or less, a melt tension of 2 g or more, excellent moldability, flexibility and heat resistance, and is excellent in various molding processes. Expresses mechanical properties.

  The aliphatic polyester resin composition of the present invention will be described in detail below.

<(A) Aliphatic polyester resin>
The aliphatic polyester resin (A) used in the present invention is preferably mainly composed of an aliphatic dicarboxylic acid unit (a) and an aliphatic diol unit (b), and if necessary, an aliphatic hydroxycarboxylic acid unit (c ), In particular,
(A) For 100 moles of aliphatic dicarboxylic acid units,
(B) Aliphatic diol unit 98 mol or more and 102 mol or less,
(C) Aliphatic hydroxycarboxylic acid unit 0 mol or more and 60 mol or less,
An aliphatic polyester comprising, in particular, a fat composed of such an aliphatic dicarboxylic acid unit (a), an aliphatic diol unit (b), and an aliphatic hydroxycarboxylic acid unit (c) introduced as necessary. A polyester polyether copolymer having a group polyester part and (d) a polyether part represented by the following general formula (1) is most preferable because it has both heat resistance and elastic modulus.

（一般式（１）中、Ｒは水素又は炭素数１以上１０以下のアルキル基を表す。ｍは１以上１０以下の整数を表し、ｎは１以上１０００以下の整数を表す。）

(In general formula (1), R represents hydrogen or an alkyl group having 1 to 10 carbon atoms. M represents an integer of 1 to 10 and n represents an integer of 1 to 1000.)

(A) Aliphatic dicarboxylic acid unit The aliphatic dicarboxylic unit (a) constituting the aliphatic polyester portion of the aliphatic polyester resin (A) is derived from an aliphatic dicarboxylic acid and / or a derivative thereof. The aliphatic dicarboxylic acid and / or derivative thereof refers to one represented by the following general formula (2), or a lower alkyl ester having 1 to 4 carbon atoms or an anhydride thereof.
HOOC-R ¹ -COOH (2)

In general formula (2), R ¹ is a single bond or a divalent aliphatic hydrocarbon group. The lower limit of the carbon number of R ¹ is usually 2 or more, and the upper limit is usually 11 or less, preferably 6 or less. R ¹ may have a branched chain or a cycloalkylene group, but is preferably a linear hydrocarbon group.

  Preferable specific examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid, dodecanedioic acid and the like, and alkyl esters or acid anhydrides thereof can also be used. . These aliphatic dicarboxylic acids and derivatives thereof may be used alone or in combination of two or more. From the physical properties of the resulting copolymer, the aliphatic dicarboxylic acid unit (a) is preferably derived from succinic acid or succinic anhydride, or a mixture of these with adipic acid.

(B) Aliphatic diol unit The aliphatic diol unit (b) is preferably derived from an aliphatic diol represented by the following general formula (3).
HO—R ² —OH (3)

In General Formula (3), R ² is a divalent aliphatic hydrocarbon group. The lower limit of the carbon number of R ² is usually 2 or more, and the upper limit is usually 11 or less, preferably 6 or less. R ² may be a branched chain or a cycloalkylene group, but is preferably a linear hydrocarbon group.

  Preferable specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1, Examples include 6-cyclohexanedimethanol. These aliphatic diols may be used alone or in combination of two or more. From the viewpoint of the physical properties of the resulting copolymer, the aliphatic diol unit (b) is particularly preferably derived from 1,4-butanediol.

  The aliphatic diol unit (b) constituting the aliphatic polyester portion of the aliphatic polyester resin (A) according to the present invention is substantially 100 mol with respect to 100 mol of the aliphatic dicarboxylic acid unit (a). The lower limit is usually 98 mol or more, preferably 99 mol or more, and the upper limit is usually 102 mol or less, preferably 101 mol or less, particularly preferably 100 mol. When there are too many or too few aliphatic diol units (b) with respect to 100 mol of aliphatic dicarboxylic acid units (a), the molecular weight of the obtained copolymer will become low and there exists a tendency for a mechanical physical property to fall.

(C) Aliphatic hydroxycarboxylic acid unit The aliphatic hydroxycarboxylic acid unit (c), which is an optional component, is derived from an aliphatic hydroxycarboxylic acid that is an aliphatic compound having a hydroxyl group and a carboxylic acid group in the molecule.

Examples of the aliphatic hydroxycarboxylic acid that can be used in the present invention include an aliphatic hydroxycarboxylic acid represented by the following general formula (4) having one hydroxyl group and one carboxylic acid group in the molecule, or an intramolecular molecule thereof. An ester or a lower alkyl ester having 1 to 4 carbon atoms is preferred.
^{HO-R 3 -COOH ... (4} )

In general formula (4), R ³ is a single bond or a divalent aliphatic hydrocarbon group. The lower limit of the carbon number of R ³ is usually 1 or more, preferably 2 or more, and the upper limit is usually 11 or less, preferably 6 or less. R ³ may be a branched chain or a cycloalkylene group. Among these, those in which a hydroxyl group and a carboxyl group are bonded to one carbon atom are preferable, and when a compound represented by the following general formula (5) is used, the polymerization rate increases, which is particularly preferable.

（一般式（５）中、ａは下限が通常０以上、好ましくは１以上であり、上限が通常１０以下、好ましくは５以下の整数である。）

(In general formula (5), a has a lower limit of usually 0 or more, preferably 1 or more, and an upper limit of usually 10 or less, preferably 5 or less.)

  Specific examples of such aliphatic hydroxycarboxylic acids include lactic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2- Examples include those obtained by ring-opening lactones such as hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, or caprolactone. These aliphatic hydroxycarboxylic acids may be used alone or in combination of two or more. In addition, when an optical isomer exists in these aliphatic hydroxycarboxylic acids, any of D-form, L-form, and racemic form may be sufficient, and the shape may be any of solid, liquid, or aqueous solution. . As the aliphatic hydroxycarboxylic acid, lactic acid and an aqueous solution thereof are particularly preferred from the standpoint of remarkable increase in polymerization rate during use and easy availability. Lactic acid is generally commercially available in 50%, 70%, and 90% aqueous solutions, and is easily available.

  The lower limit of the proportion of the aliphatic hydroxycarboxylic acid unit (c) as an optional component is usually 0 mol or more, preferably 0.02 mol or more, particularly preferably 1 with respect to 100 mol of the aliphatic carboxylic acid unit (a). The upper limit is usually 60 mol or less, preferably 30 mol or less, particularly preferably 20 mol or less. When the amount of the aliphatic hydroxycarboxylic acid unit (c) is too large, the resulting copolymer is likely to be colored, the amount of distillate at the time of production increases, and the production becomes difficult. Heat resistance tends to decrease. On the other hand, when the amount is too small, the polymerization time to reach a predetermined molecular weight tends to be long.

(D) Polyether Unit The aliphatic polyester resin (A) according to the present invention is a polyether polyester resin containing an aliphatic polyether unit (d) represented by the following general formula (1). It is preferable in that the elastic modulus can be lowered while keeping the property high.

  In general formula (1), R represents hydrogen or an alkyl group having 1 to 10 carbon atoms. Specific examples of R include hydrogen, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, n-heptyl group, and n-octyl. A hydrogen group or a methyl group is preferable, and hydrogen is most preferable in terms of reactivity.

  m is an integer having a lower limit of 1 or more, preferably 2 or more, and an upper limit of 10 or less, preferably 3 or less. n has a lower limit of 1 or more, preferably 5 or more, particularly preferably 10 or more, and an upper limit of 1000 or less, preferably 100 or less, particularly preferably 50 or less.

  This polyether unit (d) is derived from epoxides, diols, cyclic ethers and the like.

  Specific examples of such compounds include ethylene oxide, propylene oxide and the like as epoxides, and diols such as ethylene glycol, 1,2-propylene diol, 1,3-propylene diol and 1,4-butane diol as cyclic diols. Examples of ethers include tetrahydrofuran and the like. Among them, 1,4-butanediol, 1,3-propylenediol or tetrahydrofuran is preferable from the viewpoint of mechanical properties of the obtained resin.

  The content of the polyether unit (d) in the copolymer has a lower limit of usually 1% by weight or more, preferably 10% by weight or more, particularly preferably 30% by weight or more, and an upper limit of usually 90% by weight. Hereinafter, it is preferably 70% by weight or less, particularly preferably 50% by weight or less. If this amount is too small, it tends to be difficult to sufficiently reduce the elastic modulus, and if it is too large, the heat resistance tends to decrease.

  In addition, other copolymerization components can be introduced into the aliphatic polyester resin (A) used in the present invention as long as the effect is not impaired. When a trifunctional or higher polyhydric hydroxycarboxylic acid, polyhydric carboxylic acid, polyhydric alcohol or the like is added as another copolymerization component, the melt viscosity can be increased. Specific examples include malic acid, trimethylolpropane, glycerin, pentaerythritol, trimellitic acid, citric acid, and tartaric acid. The amount of these other copolymerization components is usually 0 mol or more, preferably 0.001 mol or more, more preferably 0.01 mol%, relative to 100 mol of the aliphatic carboxylic acid unit (a). Above, most preferably 0.05 mol% or more, and the upper limit is usually 5 mol% or less, preferably 1 mol% or less, more preferably 0.5 mol% or less, most preferably 0.3 mol% or less. is there. Among these, when malic acid, trimethylolpropane, citric acid, or pentaerythritol is used, the tensile elongation is improved, which is particularly preferable.

  The aliphatic polyester resin (A) according to the present invention may contain a small amount of structures other than ester bonds and ether bonds such as urethane bonds, carbonate bonds and amide bonds. In this case, the content of components other than polyester and polyether is usually 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less in the aliphatic polyester resin. When there are too many urethane bonds, heat resistance will fall, when there are too many carbonate bonds, biodegradability will become quick too much, and when there are too many amide bonds, there exists a tendency for biodegradability to become late. The form of copolymerization by these bonds may be a block copolymer, a random copolymer or a graft copolymer.

  When the aliphatic polyester-based resin (A) used in the present invention is a polyester mainly composed of the components (a) and (b) or (a) to (c), the number average molecular weight Mn has a lower limit. It is usually 10,000 or more, preferably 30,000 or more, and the upper limit is usually 300,000 or less, preferably 100,000 or less. The lower limit of the reduced viscosity ηsp / C is usually 0.5 or more, preferably 1.0 or more, most preferably 1.5 or more, and the upper limit is usually 4.0 or less, preferably 3.5 or less. Most preferably, it is 3.0 or less.

  When the aliphatic polyester resin (A) is a polyester polyether resin mainly composed of the components (a) to (d), the number average molecular weight Mn has a lower limit of usually 10,000 or more, preferably It is 30,000 or more, and the upper limit is usually 300,000 or less, preferably 10 or less. The reduced viscosity ηsp / C has a lower limit of usually 1.0 or more, preferably 1.5 or more, most preferably 2.0 or more, and an upper limit of usually 5.0 or less, preferably 4.0 or less. Most preferably, it is 3.5 or less.

  In any case, when the number average molecular weight Mn is smaller than the lower limit, sufficient strength cannot be obtained, and when the number average molecular weight Mn is larger than the upper limit, the moldability tends to be deteriorated. Further, if the reduced viscosity ηsp / C is smaller than the lower limit value, sufficient strength cannot be obtained, and if it is larger than the upper limit value, the moldability tends to be deteriorated.

<Production of Aliphatic Polyester Resin (A)>
The aliphatic polyester-based resin (A) used in the present invention comprises the above components (a) and (b), or components (a) to (c), or (a) to (d) in the presence of a polymerization catalyst. And polymerized by a known method such as melt polycondensation or solution polycondensation.

  The aliphatic diol unit (b) in the aliphatic polyester resin (A) is substantially equimolar to the aliphatic dicarboxylic acid unit (a), but the aliphatic diol is an ester in the actual production process. The lower limit is usually 100 mol or more, preferably 101 mol or more, more preferably 105 mol or more, and the upper limit with respect to 100 mol of the aliphatic dicarboxylic acid and / or its derivative. However, when used in a range of usually 200 mol or less, preferably 150 mol or less, more preferably 120 mol or less, the molar ratio of (a) aliphatic diol unit and (b) aliphatic dicarboxylic acid unit is substantially equal. Become.

  The aliphatic polyester-based resin (A) according to the present invention can be copolymerized with an aliphatic hydroxycarboxylic acid as described above. The amount of the aliphatic hydroxycarboxylic acid used in this case is an aliphatic dicarboxylic acid. The lower limit is usually 0.04 mol or more, preferably 1 mol or more, more preferably 30 mol or more, and the upper limit is usually 60 mol or less, preferably 20 mol or less, relative to 100 mol of the derivative thereof. Preferably it is 10 mol or less. If the amount of the aliphatic hydroxycarboxylic acid is small and the amount of the aliphatic hydroxycarboxylic acid unit (c) introduced is too small, the effect of improving the polymerization reactivity is hardly exhibited, and it becomes difficult to obtain a high molecular weight polyester. There is a tendency to become insufficient.

  The addition timing of the aliphatic hydroxycarboxylic acid is not particularly limited as long as it is before the polycondensation reaction. For example, esterification at the time of raw material charging or before polycondensation with the catalyst dissolved in the aliphatic hydroxycarboxylic acid solution in advance. A method of adding during the reaction or a method of adding at the same time as adding the catalyst at the time of charging the raw materials is preferable.

  When the aliphatic polyester resin (A) is a polyester polyether resin having a polyether unit (d), the amount of the compound used for introducing the polyether unit (d) described above is the amount of the polyester polyol copolymer. On the other hand, the lower limit is usually 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, particularly preferably 30% by weight or more, and the upper limit is usually 90% by weight or less, preferably 70% by weight or less. More preferably, it is 50% by weight or less.

  The addition timing of the compound for introducing the polyether unit (d) is not particularly limited as long as it is before the end of the polycondensation reaction. For example, a method of adding the raw material before the esterification reaction or during the esterification reaction Or, at the end of the esterification reaction, a method of adding to the reaction vessel before reducing the pressure is preferable.

  Any polymerization catalyst can be used, but germanium, titanium, antimony, tin, magnesium, calcium, zinc, and other metal compounds that are soluble in the reaction system can be used. These catalysts can be used alone. Or two or more of them may be used in combination. Among these, it is particularly preferable to use a germanium compound because of high polymerization activity and safety.

  Examples of the germanium compound include organic germanium compounds such as tetraalkoxygermanium, and inorganic germanium compounds such as germanium oxide and germanium chloride. Germanium oxide, tetraethoxygermanium, tetrabutoxygermanium, and the like are particularly preferable from the viewpoints of price and availability.

  The amount of these catalysts used is usually 0.001% by weight or more, preferably 0.005% by weight or more, and the upper limit is the amount of monomers used, that is, the total amount of components (a) to (d). The amount is usually 3% by weight or less, preferably 1.5% by weight or less.

  The catalyst addition time is not particularly limited as long as it is before the polyester bond is formed, but it may be added when the raw materials are charged, or may be added at the start of pressure reduction. It is particularly preferable to add at the same time as the aliphatic hydroxycarboxylic acid when the raw materials are charged, or to add the catalyst dissolved in the aliphatic hydroxycarboxylic acid or an aqueous solution thereof.

Conditions such as temperature, time, and pressure when producing the aliphatic polyester resin (A) are not particularly limited as long as the target polyester copolymer can be obtained. 150 ° C. or higher, preferably 180 ° C. or higher, and the upper limit is usually 260 ° C. or lower, preferably 230 ° C. or lower. The lower limit of the polymerization time is usually 1 hour or longer, preferably 2 hours or longer, and the upper limit is usually 15 hours or shorter. The upper limit of the degree of pressure reduction during the polycondensation reaction is usually selected from the range of 1.33 × 10 ³ Pa or less, preferably 0.27 × 10 ³ Pa or less.

<(B) Polylactic acid>
The polylactic acid (B) used if necessary in the present invention is not particularly limited, but the lower limit of the number average molecular weight Mn of the polylactic acid (B) necessary for having sufficient strength is usually 30,000 or more, preferably Is 100,000 or more, and the upper limit is usually 1,000,000 or less, preferably 500,000 or less. The molar ratio of L-form and D-form constituting polylactic acid can be used in all compositions where L / D is 100/0 to 0/100, but in terms of obtaining an aliphatic polyester resin composition having a high elastic modulus, L The body is preferably 95% or more.

  The production method of polylactic acid (B) is not particularly limited, and a method of directly dehydrating polycondensation of lactic acid or a mixture of lactic acid and aliphatic hydroxycarboxylic acid, ring-opening of melt polymerization of a cyclic dimer of lactic acid Examples thereof include a polymerization method, a ring-opening polymerization method in which a cyclic dimer of lactic acid and an aliphatic hydroxycarboxylic acid is melt-polymerized, and a method in which a mixture of lactic acid, an aliphatic diol and an aliphatic dicarboxylic acid is directly subjected to dehydration polycondensation.

  In the present invention, the use ratio of the polylactic acid (B) in the total 100 parts by weight of the aliphatic polyester resin (A) and the polylactic acid (B) is 0 part by weight or more at the lower limit and 50 parts by weight or less at the upper limit. The amount is preferably 30 parts by weight or less.

  By using polylactic acid (B), it is possible to increase the hardness and elastic modulus, which are indices of flexibility, but if the use ratio is more than the above upper limit value, the hardness and elastic modulus tend to be too high. is there.

<(C) Plasticizer>
The plasticizer (C) used in the present invention is not particularly limited. Specifically, methyl adipate, diethyl adipate, diisopropyl adipate, di-n-propyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, Diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, fatty acid ester such as methyl acetyl lysylate, glycerin ester such as triacetin, diethyl maleate, dibutyl maleate , Maleic acid and fumaric acid ester such as dioctyl maleate, dibutyl fumarate and dioctyl fumarate, adipic acid 1,3-butylene glycol, polyester such as epoxidized soybean oil -Trimellitic acid ester such as epoxidized ester, trioctyl trimellitate, triethylene glycol diacetate, tributyl acetyl citrate, glycerin diacetomonopropionate, glycerin diacetomonocaprylate, glycerin diacetomonocaprate, glycerin diacetomono Acetylated monoglycerides such as laurate, glycerin diacetomonooleate, glycerin monoacetomonobehenate, (glycerin monoacetomonostearate), diglycerin acetate, decaglycerin propionate, tetraglycerin caprylate, decaglycerin laurate, deca Examples thereof include polyglycerol fatty acid esters such as glycerol oleate and decaglycerol behenate, and rosin derivatives. These plasticizers may be used alone or in combination of two or more.

  Among them, epoxidized soybean oil, acetylated monoglycerides such as glycerin diacetomonocaprylate, glycerin diacetomonolaurate, and glycerin diacetomonooleate, diglycerin acetate, decaglycerin caprylate, decaglycerin laurate, decaglycerin oleate, and the like are preferable. Polyglycerin fatty acid ester and the like.

  In particular, when a polyglycerol acetate such as diglycerol acetate is used, it is preferable from the viewpoint of plasticizing effect on the polymer and low bleeding property.

  The addition amount of the plasticizer (C) used in the present invention is based on 100 parts by weight of the aliphatic polyester resin (A) or the resin component composed of the aliphatic polyester resin (A) and the polylactic acid (B). The lower limit is 1 part by weight or more, preferably 3 parts by weight or more, more preferably 5 parts by weight or more, and the upper limit is 80 parts by weight or less, preferably 40 parts by weight or less, more preferably 20 parts by weight or less. .

  If the amount of the plasticizer (C) is too small, there is a tendency that the plastic effect is small and sufficient flexibility cannot be obtained. On the other hand, if the amount is too large, the heat resistance of the composition is poor or the plasticizer bleeds out. There is a case.

<(D) Organic peroxide>
In this invention, as an organic peroxide (D) used as needed, both an aromatic type and a fatty type can be used. Specific examples include ketone peroxide compounds, diacyl peroxide compounds, hydroperoxide compounds, dialkyl peroxide compounds, peroxyketal compounds, peroxyester compounds, peroxycarbonate compounds, and the like. .

  Examples of the ketone peroxide compound include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide.

  Examples of diacyl peroxide compounds include isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide, benzoyl peroxide, and p-chlorobenzoyl peroxide.

  Examples of hydroperoxide compounds include t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and the like. Can be mentioned.

  Examples of the dialkyl peroxide compound include di-t-butyl peroxide, t-butyl-α-cumyl peroxide, di-t-cumyl peroxide, 1,4-bis ((t-butyldioxy) isopropyl) benzene, 1, 3-bis ((t-butyldioxy) isopropyl) benzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) benzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) ) Hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne and the like.

  Examples of peroxyketal compounds include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2, Examples include 2-bis (t-butylperoxy) butane.

  As peroxyester compounds, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxyoctoate, t-butyl peroxypivalate, t-butylperoxyneodecanoate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxybenzoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, etc. Is mentioned.

  Examples of peroxycarbonate compounds include bis- (2-ethylhexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, disec-butyl peroxydicarbonate, di-n-propyl peroxydicarbonate, bis (3-methoxy Butyl) peroxydicarbonate, bis (2-ethoxyethyl) peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, and the like.

  These organic peroxides (D) may be used individually by 1 type, and may use 2 or more types together.

  Among them, an organic peroxide having a half-life temperature of 1 minute (one-minute half-life temperature) in the range of 100 to 200 ° C. is preferable from the viewpoint of reactivity. Specifically, ketone peroxide compounds such as methyl ethyl ketone peroxide (1 minute half-life temperature 171 ° C.), cyclohexanone peroxide (174 ° C.); diacyl peroxide compounds such as benzoyl peroxide (130 ° C.); Di-t-butyl peroxide (193 ° C.), t-butyl-α-cumyl peroxide (178 ° C.), di-t-cumyl peroxide (171 ° C.), 2,5-dimethyl-2,5 -Dialkyl peroxide compounds such as bis (t-butylperoxy) hexane (179 ° C) and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne (193 ° C); Butyl peroxyacetate (159 ° C), t-butylperoxylaurate (165 ° C), t-butylpero Shibenzoeto (the 166 ° C.), 2,5-dimethyl-2,5-di (benzoyl peroxy) hexane (the same 162 ° C.) peroxy ester compounds such as and the like.

  Among these, from the viewpoint of reactivity, an organic peroxide having a half-life of 0.1 to 10 times the residence time of the aliphatic polyester resin composition at the kneading temperature in the extruder is particularly preferred. -T-butyl peroxide, dicumyl peroxide, and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane are particularly preferred.

  The amount of the organic peroxide (D) added depends on the type and reaction temperature, but is an aliphatic polyester resin (A) or a resin component comprising an aliphatic polyester resin (A) and polylactic acid (B). The lower limit is usually 0.001 parts by weight or more, preferably 0.01 parts by weight or more, more preferably 0.02 parts by weight or more, and the upper limit is usually 5 parts by weight or less, preferably 100 parts by weight. 2 parts by weight or less, more preferably 1 part by weight or less.

  If the amount of the organic peroxide (D) is too small, the effect as a cross-linking agent is not sufficient, so that a sufficient melt tension cannot be obtained, and the workability tends to deteriorate. On the other hand, if the amount is too large, the viscosity may be too high and melt molding may be difficult.

<(E) Compound having two or more vinyl groups>
Specific examples of the compound having two or more vinyl groups used in the present invention include saturated aliphatic carboxylic acid esters such as divinyl adipate and diallyl adipate; vinyl (meth) acrylate and (meth) acrylic. Allyl acid, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, polyester di (meth) acrylate, vinyl crotonic acid, vinyl undecylenate, diallyl maleate , Unsaturated aliphatic carboxylic acid esters such as diallyl fumarate and diallyl itaconate; carbocyclic carboxylic acid esters such as diallyl phthalate and vinyl cinnamate; ethers such as diallyl ether; and divinylbenzene and cyanuric acid Triallyl (however, "(Meth) acrylic acid" also applies to "acrylic acid" and indicates "methacrylic acid". "(Meth) acrylate".).

  Among these, from the viewpoint of reactivity, it is preferable to use unsaturated aliphatic carboxylic acid ester or divinylbenzene. Among unsaturated aliphatic carboxylic acid esters, (meth) acrylic acid esters are preferable, and (meth) acrylic acid polyhydric alcohol esters such as trimethylolpropane tri (meth) acrylate are particularly preferable.

  These compounds (E) having two or more vinyl groups may be used alone or in combination of two or more.

  The addition amount of the compound (E) having two or more vinyl groups depends on the kind and reaction temperature, but the aliphatic polyester resin (A), the aliphatic polyester resin (A), and the polylactic acid (B) The lower limit is usually 0.001 part by weight or more, preferably 0.01 part by weight or more, more preferably 0.02 part by weight or more, and the upper limit is usually 5 parts by weight. The amount is preferably 2 parts by weight or less, more preferably 1 part by weight or less.

  If the compounding amount of the compound (E) having two or more vinyl groups is too small, the effect as a crosslinking aid is not sufficient, so that a sufficient melt tension cannot be obtained and the workability tends to deteriorate. On the other hand, if the amount is too large, the viscosity may be too high and melt molding may be difficult.

<The manufacturing method of the aliphatic polyester-type resin composition of this invention>
The aliphatic polyester-based resin composition of the present invention is usually the components (A) and (C), or the components (A) to (C), or, if necessary, the component (D) or the component (D). And the component (E) are uniformly mixed using a high-speed stirrer, a low-speed stirrer or the like, and then melt-kneaded with a single-screw or multi-screw extruder.

  The method of supplying these blended components to the extruder is (A), (C) component, or (A) to (C) component, or if necessary, further (D) component or (E) component. A batch method in which the mixture is uniformly mixed using a stirrer, a low-speed stirrer, or the like and then supplied from the hopper may be used, or a separate addition method in which it is separately supplied directly to the extruder may be used. When performing the separate addition method, the components (A), (B), (D) and (E) can be supplied using the side feeder of the extruder, and the component (C) is a plunger. It can supply using a pump, a gear pump, etc. When this melt-kneading is performed, it is preferably performed in the presence of nitrogen.

  The lower limit of the temperature during melt-kneading is usually 100 ° C. or higher, preferably 110 ° C. or higher, and the upper limit is usually 280 ° C. or lower, preferably 250 ° C. or lower.

  The melt kneading time has a lower limit of usually 5 seconds or more, preferably 10 seconds or more, and an upper limit of usually 5 minutes or less, preferably 2 minutes or less.

  In addition, in the aliphatic polyester-type resin composition of this invention, unless the effect of this invention is impaired, additives other than the said (A)-(E) component as needed, for example, a lubricant, a wax , Coloring agents, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants, and the like can be used.

<Characteristics of Aliphatic Polyester Resin Composition of the Present Invention>
The aliphatic polyester resin composition of the present invention has a flexural modulus of 500 MPa or less, a hardness of 65 or less, and a melt tension of 2 g or more.

  In the present invention, the flexural modulus, hardness and melt tension are values measured by the following methods.

  Bending elastic modulus: Three-point bending measured by press molding an aliphatic polyester resin composition into a sheet shape having a thickness of 2 mm under conditions of 180 ° C. and 10 MPa, and measuring this sheet-like molded product in accordance with JIS K 7203, 6301 Refers to the rigidity.

  Hardness: A value measured by the method D in accordance with JIS K 7215 for the sheet-like molded product.

  Melt tension: A value obtained by measuring the tension at a predetermined temperature when a molten resin extruded under a specified condition is drawn into a filament at a specified take-up speed by a capillograph manufactured by Toyo Seiki Seisakusho. The used capillary pillar has a length of 8.00 mm, an inner diameter of 2.0959 mm, an outer diameter of 9.5 mm, an extrusion speed of 1.0 cm / min, and a take-up speed of 3.9 m / min. The melt tension was measured at two temperatures at a load of 2.16 kg, the melt flow ratio (MFR) was measured, the temperature at which the MFR was 10 g / min. Was obtained, and the value measured at that temperature (“Plastic Processing Technology Handbook”) (Refer to the Institute of Polymer Science, published by Nikkan Kogyo Shimbun, etc.).

  The upper limit value of the flexural modulus of the aliphatic polyester resin composition of the present invention is 500 MPa or less, preferably 450 MPa or less, most preferably 400 MPa or less, and the lower limit value is usually 20 MPa or more, preferably 30 MPa or more. . When this value is too large, the obtained molded product becomes hard and tends to be inappropriate as a flexible molded product such as an automobile interior material and a medical tube.

  In addition, the upper limit of the hardness of the aliphatic polyester resin composition of the present invention is 65 or less, preferably 60 or less, more preferably 45 or less, and the lower limit is usually 20 or more, preferably 30 or more. . When the hardness exceeds 65, sufficient flexibility cannot be obtained, and a molded product obtained in the same manner as the bending elastic modulus becomes hard and tends to be inappropriate as a flexible molded product such as an automobile interior material.

  The lower limit of the melt tension of the aliphatic polyester resin composition of the present invention is 2 g or more, preferably 3 g or more, more preferably 4 g or more, and the upper limit is preferably 100 g or less, more preferably 80 g or less. It is. If this value is too small, melt moldability tends to deteriorate, and if it is too large, melt molding tends to be impossible depending on conditions.

<Method for Molding Aliphatic Polyester Resin Composition of the Present Invention>
The aliphatic polyester resin composition of the present invention can be extruded, injected, or thermoformed using an extruder, an injection molding machine, or the like used for ordinary plastic molding. In this case, the molding temperature is preferably 120 to 200 ° C. In order to blend the polymer blend and the plasticizer, it is desirable to use a twin screw extruder. The resin composition melted in the extruder is formed into a sheet or film by T-die, inflation or the like. Furthermore, the sheet or film of the aliphatic polyester resin composition of the present invention is a material suitable for so-called secondary processing that imparts secondary and tertiary shapes such as vacuum forming, stretching processing, blow processing and the like. is there.

  EXAMPLES Specific examples of the present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

  The characteristic values in the following examples are measured by the following method.

(1) Number average molecular weight (Mn)
It measured by the gel permeation chromatography (GPC) method. The sample was dissolved in chloroform and measured by polystyrene conversion using a GPC apparatus (manufactured by Tosoh Corporation, HLC-8120 type). The column used was TSKgel SuperHM-M (manufactured by Tosoh Corporation).
(2) Reduced viscosity (ηsp / C)
It was determined from the solution viscosity measured in phenol / tetrachloroethane (1: 1 weight ratio) at 30 ° C. with a solution concentration of 0.5 g / dl.
(3) Polymer composition
^The composition was calculated from the area ratio of the spectrum obtained by ¹ H-NMR.
(4) Flowability (melt flow ratio (MFR))
Measurement was performed at 190 ° C. under a load of 2.16 kg in accordance with JIS K7210.
(5) Flexural modulus, tensile test, hardness The aliphatic polyester resin compositions of Examples and Comparative Examples were press-molded into a sheet shape having a thickness of 2 mm under conditions of 180 ° C. and 10 MPa, and in accordance with JIS K 7203, 6301. The three-point bending rigidity (flexural modulus), tensile breaking strength, and tensile breaking elongation were measured. The tensile speed was 200 m / mm.
The hardness was measured by the D method according to JIS K 7215.
(6) Melt tension Capillograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used. The measurement was performed using an orifice having a length L = 8.1 mm and an inner diameter D = 2.005 mm at an extrusion speed of 10 mm / min and a take-up speed of 4 mm / min. MFR was measured at a load of 2.16 kg at two appropriate temperatures (150 ° C. and 190 ° C. in the following example), and the MFR was 10 g / 10 min. The melt tension was measured at the following temperature.
(7) Plasticizer bleed property Using a hot press machine (product name “mini test press 10” manufactured by Toyo Seiki Co., Ltd.), the press sheet obtained under the conditions of 180 ° C. and 15 MPa was left at 80 ° C. for 12 hours and left to stand. By visually observing the appearance of the subsequent sheet, the bleeding property was evaluated according to the following criteria.
A: There is no problem with no significant difference in appearance. B: There is a slight surface gloss, but there is no problem.

  As the aliphatic polyester resin, the aliphatic polyester resins (A1) to (A3) produced in Preparation Examples 1 to 3 below were used.

Preparation Example 1: Production of Aliphatic Polyester Resin (A1) In a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen introducing tube, a heating device, a thermometer, and an auxiliary agent addition port, 118.1 g of succinic acid, 1,4- 99.1 g of butanediol, 6.3 g of 90% lactic acid aqueous solution in which 1% by weight of germanium oxide is dissolved in advance (6.3 mol with respect to 100 mol of succinic acid), and 0.2 g of malic acid (with respect to 100 mol of succinic acid) , 0.15 mol), and reacted in a nitrogen atmosphere at 180 ° C. for 0.5 hour, then heated to 220 ° C. and reacted for 0.5 hour. Subsequently, a polymerization reaction was performed for 2.5 hours under a reduced pressure of 0.07 × 10 ³ Pa. The obtained polymer was milky white, the number average molecular weight Mn was 75,300, and the melting point was 110 ° C. The introduction rate of lactic acid by ¹ H-NMR was 6.3 mol with respect to 100 mol of succinic acid.

Preparation Example 2: Production of Aliphatic Polyester Resin (A2) Same as Preparation Example 2, except that 118.1 g of succinic acid and 99.1 g of 1,4-butanediol were used as raw materials, and lactic acid and malic acid were not used. And a polymer having a number average molecular weight Mn of 73200 was obtained.

Preparation Example 3 Production of Aliphatic Polyester Polyether Resin (A3) 94.5 g of succinic acid and 1,4-butane as a raw material in a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a pressure reducing port 76.1 g of diol, polytetramethylene glycol having a number average molecular weight of 2,000 (PTMG: 35.2 g in the general formula (1), m = 3, R = H), and 1 wt% of germanium oxide were dissolved in advance. 4.85 g of 90% lactic acid aqueous solution was charged. Nitrogen gas was introduced while stirring the contents of the container, and the inside of the system was put into a nitrogen atmosphere by vacuum replacement. Next, the temperature in the system was increased to 220 ° C. while stirring, and the reaction was performed at this temperature for 1 hour. Then, the temperature was raised to over 30 minutes 230 ° C., and under reduced pressure so as to 0.07 × ¹⁰ 3 Pa over 1 hour 30 minutes at the same time, subjected to 4.5 hours at 0.07 × ¹⁰ 3 Pa The polymerization was terminated to obtain a white translucent aliphatic polyester polyether copolymer. The reduced viscosity (ηsp / C) of the obtained copolymer was 1.91. Moreover, the molar fraction of each component in the polyester part in the copolymer was 49.4% succinic acid units, 48.9% 1,4-butanediol units, and 1.8% lactic acid units. The weight fraction of the polyether part in the copolymer was 20.0%.

  Moreover, the following were used as polylactic acid, a plasticizer, an organic peroxide, and a compound having two or more vinyl groups.

[Polylactic acid (B1)]
Product name “Lacty # 5400” manufactured by Shimadzu Corporation (number average molecular weight Mn: 88000, MFR: 4.5 g / 10 min., Melting point 173 ° C.)
[Plasticizer (C1)]
Polyglycerin acetate manufactured by Riken Vitamin Co., Ltd. Trade name “Riquemar PL710”
[Organic peroxide (D1)]
2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, manufactured by Nippon Oil & Fats Co., Ltd. Trade name “Perhexa 25B”
[Compound (E1) having two or more vinyl groups]
Trimethylolpropane trimethacrylate [compound having two or more vinyl groups (E2)] manufactured by Wako Chemical Co., Ltd.
Divinylbenzene manufactured by Wako Chemical Co., Ltd.

Examples 1-8 and Comparative Examples 1-7
In the compounding described in Table 1, the aliphatic polyester resin produced in Preparation Examples 1 to 3, the polylactic acid, the plasticizer, the organic peroxide, and the compound having two or more vinyl groups were mixed in a twin screw extruder ( The product was kneaded at 1 kg / hr and 190 ° C. using a product manufactured by Technobel Co., Ltd., product name: KZW15). The resulting composition was subjected to an evaluation test by the above method. The results are shown in Table 1.

  Since the aliphatic polyester resin composition of the present invention has sufficient mechanical strength and can be subjected to various molding processes such as extrusion molding and injection molding, it can be used for various parts, automotive interior members, sheets, etc. It can be used for other molded products.

Claims (8)

(A) a resin component comprising an aliphatic polyester resin;
(C) Plasticizer A resin composition obtained by melt-kneading 1 to 80 parts by weight with respect to 100 parts by weight of the resin component, wherein the flexural modulus is 500 MPa or less, the hardness is 65 or less, and the melt tension is An aliphatic polyester resin composition characterized by being 2 g or more. (A) Aliphatic polyester resin 50 parts by weight or more and 100 parts by weight or less,
And (B) a resin component composed of 50 parts by weight or less of polylactic acid (provided that the total of (A) and (B) is 100 parts by weight),
(C) Plasticizer A composition obtained by melt-kneading 1 to 80 parts by weight with respect to 100 parts by weight of the resin component, wherein the flexural modulus is 500 MPa or less, the hardness is 65 or less, and the melt tension is 2 g. An aliphatic polyester resin composition characterized by the above. The aliphatic polyester part of the aliphatic polyester resin (A)
(A) an aliphatic dicarboxylic acid unit,
And (b) Aliphatic diol unit The aliphatic polyester-based resin composition according to claim 1 or 2, which is composed of 98 mol or more and 102 mol or less with respect to 100 mol of the aliphatic dicarboxylic acid unit (a). The aliphatic polyester part of the aliphatic polyester resin (A)
(A) an aliphatic dicarboxylic acid unit,
(B) Aliphatic diol unit The aliphatic dicarboxylic acid unit (a) is 98 mol to 102 mol with respect to 100 mol,
And (c) Aliphatic hydroxycarboxylic acid unit The aliphatic polyester-based resin composition according to claim 1 or 2, comprising 60 mol or less per 100 mol of the aliphatic dicarboxylic acid unit (a). The aliphatic polyester resin (A) is a polyester polyether copolymer having an aliphatic polyester part and (d) a polyether part represented by the following general formula (1). The aliphatic polyester-based resin composition according to any one of the above.

(In general formula (1), R represents hydrogen or an alkyl group having 1 to 10 carbon atoms. M represents an integer of 1 to 10 and n represents an integer of 1 to 1000.)   The proportion of the polyether part (b) represented by the general formula (1) is 1% by weight or more and 90% by weight or less in the polyester polyether copolymer of the aliphatic polyester resin (A). 5. The aliphatic polyester resin composition according to 5.   The aliphatic polyester resin composition according to any one of claims 1 to 6, wherein 0.001 to 5 parts by weight of an organic peroxide (D) is further melt-kneaded with 100 parts by weight of the resin component. object.   The aliphatic polyester resin composition according to claim 7, wherein 0.001 to 5 parts by weight of a compound (E) having two or more vinyl groups is melt-kneaded with 100 parts by weight of the resin component.