JP3339297B2 - Aliphatic polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aliphatic polyester composition having a practically sufficient strength and a high melting point. More specifically, the present invention relates to an aliphatic polyester composition that can be molded by a general-purpose plastic molding machine such as injection molding, blow molding, and extrusion molding. According to the present invention, it is possible to provide an aliphatic polyester composition having excellent physical properties and biodegradability.

[0002]

2. Description of the Related Art Conventionally, high molecular weight polyesters having a number average molecular weight of about 10,000 or more, which have been used for molding films, fibers and other molded articles, are made of aromatic polyesters such as PE made from terephthalic acid and ethylene glycol.
It was no exaggeration to say that it was limited to T, or PBT made from terephthalic acid and 1,4-butanediol. On the other hand, the practical use of aliphatic polyesters was extremely difficult because of the relatively low melting point of aliphatic polyesters and the number average molecular weight of 15, It was difficult to obtain a copolymer having a number average molecular weight of about 10,000, which was generally difficult to obtain, and a practically sufficient strength could not be obtained with a copolymer having a number average molecular weight of about 10,000.

As a result of intensive studies, the present inventors have found that, in the presence of a catalyst, aliphatic hydroxycarboxylic acids represented by lactic acid, which are mainly composed of aliphatic diols and aliphatic dicarboxylic acids or derivatives thereof as aliphatic polyesters. By using a catalyst composed of a germanium compound and coexisting in a specific amount reaction system, the polymerization rate is extremely increased, and as a result, a high molecular weight aliphatic polyester resin having a molecular weight of 10,000 or more that can be formed into a film or the like is obtained. Was found.
(See Japanese Patent Application No. Hei 7-221969) However, although these aliphatic polyesters have sufficient elongation, it has been found that the strength such as the modulus of elasticity is slightly low depending on the application, and that they are too soft. On the other hand, polylactic acid, on the other hand, has a high modulus of elasticity, but lacks elongation, that is, is hard and brittle, so that its use is also limited.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an aliphatic polyester composition having excellent strength and elongation, which can be applied to various fields such as films, molded articles, fibers and the like. .

[0005]

According to the present invention, (a) an aliphatic diol, (b) an aliphatic dicarboxylic acid or a derivative thereof, and (c) a bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof are copolymerized. Polylactic acid (B) while maintaining the excellent flexibility of aliphatic polyester (A)
When an aliphatic polyester (A) and a polylactic acid (B) were melt-blended for the purpose of imparting excellent strength, they were found to compensate for the respective disadvantages of both.
An aliphatic polyester composition having excellent strength and elongation was obtained.

That is, the gist of the present invention is that (a) an aliphatic diol, (b) an aliphatic dicarboxylic acid or a derivative thereof,
And (c) copolymerized with a bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof, having a number average molecular weight of 10,000 to 3
99-1 parts by weight of an aliphatic polyester (A) having a molecular weight of 100,000 and polylactic acids (B) 1-99 having a number average molecular weight of 30,000 or more
An aliphatic polyester composition characterized in that parts by weight are melt-blended.

Since the aliphatic polyester composition obtained by the present invention has sufficient strength and elongation, it can impart desirable properties to a molded article, for example, a film or the like using the same. By changing the blend ratio, an aliphatic polyester composition having desired strength and elongation can be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The aliphatic polyester (A) used in the present invention comprises (a) an aliphatic diol and (b)
The reaction between the aliphatic dicarboxylic acid or its derivative and (c) the bifunctional aliphatic hydroxycarboxylic acid or its derivative is performed by the action of a germanium catalyst. In the present invention, “aliphatic” includes “alicyclic”.

<(A) Aliphatic diol> The (a) aliphatic diol used in the present invention is an aliphatic compound having the above-mentioned meaning and is a compound having two hydroxyl groups. Is represented by the following formula (I).

[0010]

HO-R ₁ -OH (I)

Wherein R ₁ is a divalent aliphatic hydrocarbon group,
It preferably has 2 to 11 carbon atoms, particularly preferably 2 to 6 carbon atoms. As described above, R ₁ includes a cycloalkylene group, and R ₁ may have a branched chain. Preferred R ₁ is — (CH ₂ ) _n —, where n is an integer of 2 to 11, and preferably an integer of 2 to 6.) Preferred specific examples of the aliphatic diol that can be used in the present invention include: , Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. These may be used alone or a mixture thereof. The aliphatic diol is particularly preferably 1,4-butanediol from the viewpoint of the physical properties of the obtained copolymer.

<(B) Aliphatic dicarboxylic acid or derivative thereof> (b) Aliphatic dicarboxylic acid or derivative thereof
Compounds represented by the following formula (II), or lower alkyl esters having 1 to 4 carbon atoms, or anhydrides thereof.

[0013]

Embedded image HOOC-R ₂ —COOH (II)

(Wherein R ₂ is a direct bond or a divalent aliphatic hydrocarbon group, preferably having 1 to 11 carbon atoms, particularly preferably 1 to 6 carbon atoms. R ₂ is a cycloalkylene group) The inclusion of R ₂ is as described above, and may have a branched chain.
H ₂ ) _m −. However, m represents 0 or an integer of 1 to 11, preferably 0 or an integer of 1 to 6.) Specific preferred examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid. ,
Suberic acid, dodecanedioic acid and the like can be mentioned, and specific examples of the derivative include these acid anhydrides. From the physical properties of the obtained copolymer, the component (b) is preferably succinic acid or succinic anhydride, or a mixture thereof with adipic acid. These aliphatic dicarboxylic acids or derivatives thereof may be used in combination of the same and / or different compounds.

<(C) Bifunctional aliphatic hydroxycarboxylic acid or derivative thereof> The bifunctional aliphatic hydroxycarboxylic acid or derivative thereof used in the present invention has one hydroxyl group and one carboxylic acid group in the molecule. Is not particularly limited as long as it has a compound or a derivative thereof,
Compounds represented by the following formula (III), or lower alkyl esters having 1 to 4 carbon atoms thereof, or intramolecular esters thereof are preferred.

[0016]

## STR00004 ## HO-R ₃ -COOH (III)

(Wherein R ₃ is a divalent aliphatic hydrocarbon group,
It is preferably a divalent aliphatic hydrocarbon group having 1 to 11 carbon atoms, particularly preferably 1 to 6 carbon atoms. It is apparent from the above that R ₃ may include a cycloalkylene group, but a chain hydrocarbon is preferred. "Chain-like"
Is intended to include a branched chain. More preferably, compounds having a hydroxyl group and a carboxyl group on one carbon atom, in particular of the formula

[0018]

Embedded image

Wherein a is 0 or an integer of 1 or more, preferably 0 or 1 to 10, more preferably 0 or 1.
To 5). Use of the bifunctional aliphatic hydroxycarboxylic acid represented by the above formula increases the polymerization rate. Specific examples of the bifunctional aliphatic hydroxycarboxylic acid include lactic acid, cholic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, Lactones such as hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, or caprolactone, or a mixture thereof, and the like are mentioned. When these have optical isomers, D
It may be in any of the form, L form, or racemic form, and may be in the form of a solid, liquid, or aqueous solution. Particularly, lactic acid and an aqueous solution thereof which are particularly remarkable in increasing the polymerization rate during use and are easily available are preferred. Lactic acid is 5
0%, 70%, and 90% aqueous solutions are generally commercially available and readily available.

<Production of Aliphatic Polyester (A)> The aliphatic polyester (A) according to the present invention comprises components (a) to
It is produced by a method of reacting (c) under polyester production conditions in the presence of a catalyst comprising a germanium compound. The amount of the aliphatic diol (a) used is substantially equimolar to the aliphatic dicarboxylic acid or its derivative (b), but may be distilled during the esterification reaction in the actual production process. Therefore, it is used in an amount of 100 to 150 mol, preferably 105 to 130 mol, per 100 mol of the aliphatic dicarboxylic acid or a derivative thereof.

The amount of (c) the bifunctional aliphatic hydroxycarboxylic acid or its derivative used in the present invention is generally 0.04 to 60 mol, preferably 1 to 100 mol per 100 mol of the aliphatic dicarboxylic acid or its derivative. It is 20 mol, more preferably 3 to 10 mol. If the amount of the bifunctional aliphatic oxycarboxylic acid or its derivative is too small, the effect of improving the polymerization reactivity is hardly exhibited, and it becomes difficult to obtain a high molecular weight polyester, and if it is too large, the heat resistance and strength are insufficient.

The timing of adding the bifunctional aliphatic hydroxycarboxylic acid or its derivative is not particularly limited as long as it is before the polyester formation reaction. For example, (1) the catalyst is dissolved in advance in the aliphatic hydroxycarboxylic acid or its derivative solution. A method in which the catalyst is added at the time of charging the raw material or during the esterification reaction in a state, or (2) a method in which the catalyst is added during the charging of the raw material and added at the same time, is preferable. The production of the aliphatic polyester (A) according to the present invention is generally carried out using the above raw materials in the presence of a catalyst comprising a germanium compound.

The catalyst comprising a germanium compound used in the present invention may be one or two of a germanium compound, and any catalyst that can be used for producing a germanium compound and a known polyester, such as titanium,
It can be used in combination with a metal catalyst soluble in a reaction system such as antimony, tin, magnesium, zinc, calcium and the like. As the germanium compound, for example, an organic germanium compound such as tetraalkoxygermanium, or an inorganic germanium compound such as germanium oxide and germanium chloride is particularly preferable. From the viewpoint of price and availability, germanium oxide, tetraethoxygermanium, tetrabutoxygermanium and the like are particularly preferable. The amount of these catalysts used is generally 0.001 to 3% by weight, more preferably 0.03% by weight, based on the amount of monomers used, that is, the total amount of components (a) to (c).
0.5 to 1.5% by weight. The timing of adding the catalyst is not particularly limited as long as it is before the production of the polyester, but may be added at the time of charging the raw materials, or may be added at the start of pressure reduction. It is preferable to add the bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof simultaneously with the preparation of the raw material, or to dissolve the catalyst in a bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof or an aqueous solution thereof and then add the same.

The conditions such as temperature, time and pressure for producing the aliphatic polyester (A) are not particularly limited as long as the desired aliphatic polyester can be obtained. Preferably 180 to 23
It is preferable that the polymerization temperature is 0 ° C, the polymerization time is 1 hour or more, preferably 2 to 15 hours, and the degree of reduced pressure during the polycondensation reaction is 10 mmHg or less, more preferably 2 mmHg or less.

<Aliphatic Polyester (A)> The aliphatic polyester (A) of the present invention comprises the components (a) and (b) as main polyester members. When the raw materials are blended in the blending ratio, generally, the molar ratio of (a) the aliphatic diol unit and (b) the aliphatic dicarboxylic acid or its derivative unit becomes substantially equal, and the entire constitution of the aliphatic polyester When the number of moles of the components is 100 moles, (c) the bifunctional aliphatic hydroxycarboxylic acid or its derivative unit is 0.0%
2 to 30 mol. In particular, when (c) the bifunctional aliphatic hydroxycarboxylic acid or its derivative component is lactic acid,
The compatibility with the polylactic acid (B) is enhanced, which is very preferable.

The number average molecular weight Mn of the aliphatic polyester (A) used in the present invention is generally from 10,000 to 300,000, usually from 30,000 to 300,000. Further, other copolymer components can be introduced into the aliphatic polyester used in the present invention as long as the effect is not impaired.
As other copolymerization components, it is preferable to add a trifunctional or higher polyhydric hydroxycarboxylic acid, a polyhydric carboxylic acid, a polyhydric alcohol, or the like because the melt viscosity can be increased. Specific examples include malic acid, trimethylolpropane, glycerin, pentaerythritol, and trimellitic acid. From the physical properties of the obtained aliphatic polyester, malic acid, trimethylolpropane and glycerin are particularly preferred.

<Polylactic acid (B) and method for producing the same> The polylactic acid (B) used in the present invention is not particularly limited, but has a number average molecular weight of 3 to have sufficient strength.
It is 10,000 or more, preferably 100,000 or more. From the physical properties of the obtained polylactic acid, the molar ratio of the L-form to the D-form constituting the polylactic acid can be used in all compositions where L / D is 100/0 to 0/100. When high elastic modulus is desirable, L-form is 95%
It is preferable that it is above. The method for producing polylactic acid is not limited in some cases, and examples thereof include a ring-opening polymerization method via lactide and a direct polycondensation method of lactic acid.

The mixing ratio of the aliphatic polyester (A) and the polylactic acid (B) is 1 to 99 parts by weight of the aliphatic polyester (A) and 100 parts by weight of the resulting composition. It is 99 to 1 part by weight. When excellent in flexibility and maintaining the strength of the aliphatic polyester (A),
The mixing ratio of the aliphatic polyester (A) and the polylactic acid (B) is such that the aliphatic polyester (A) is 60 to 99 parts by weight, the polylactic acid (B) is 40 to 1 parts by weight, preferably the aliphatic polyester ( A) is 70 to 99 parts by weight, and polylactic acid (B) is 30 to 1 parts by weight. The compositions obtained with these mixing ratios not only have strength but also have excellent elongation than the aliphatic polyester (A). In addition, when elongation is given while maintaining high elasticity of polylactic acid (B), aliphatic polyester (A) and polylactic acid (B)
The mixing ratio of aliphatic polyester (A) is 40 to 1 part by weight, polylactic acid (B) is 60 to 90 parts by weight, preferably aliphatic polyester (A) is 30 to 1 part by weight, polylactic acid (B). Is 70 to 99 parts by weight. Mixing is performed in a molten state of the above-mentioned components, and all known kneading techniques can be used.

The aliphatic polyester composition of the present invention may be used in combination with a lubricant, a wax, a coloring agent, a filler, a stabilizer, and the like, if necessary, as long as the effects of the present invention are not impaired. Of course

The aliphatic polyester composition thus obtained has flexibility and sufficient strength, and can be subjected to various molding processes such as an injection molding method, a hollow molding method, and an extrusion molding method. laminate film, sheet, plate, film such as stretch sheet and multi-porous film, synthetic paper, Mo <br/> Nofiramen bets and filaments, such as multi filaments
It can be used for various molded products such as fabrics, nonwoven fabrics, blow bottles and foams.

[0031]

The following examples are provided to explain the present invention more specifically, but the present invention is not limited to these examples unless it exceeds the gist of the present invention. The characteristic values in the examples were measured by the following methods.

(1) Number average molecular weight (Mn), weight average molecular weight (Mw) Gel permeation chromatography (GP
It measured by the C) method. The sample was dissolved in chloroform, and measured in terms of polystyrene using an HLC-8020 type GPC apparatus manufactured by Tosoh Corporation. Column is PLge
1-10 μ-MIX was used.

(2) Polymer composition The composition was calculated from the area ratio of the spectrum obtained by ¹ H-NMR.

(3) Tensile test From the aliphatic polyester compositions obtained in Examples and Comparative Examples, a 0.30 mm-thick film was prepared by a tabletop hot pressing method, and a film was prepared from this film according to JIS K7127. No. dumbbell was created. About this dumbbell,
Based on JIS K7127, the yield strength, breaking strength, breaking elongation, and elastic modulus were measured.

[Adjustment Example 1] 118.1 g of succinic acid (b) and 1,4-butanediol were placed in a 300 ml reactor equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. 99.1 g of (a), 6.3 g of a 90% aqueous lactic acid (c) solution in which germanium oxide was previously dissolved at 1% by weight (6.3 mol per 100 mol of succinic acid),
0.2 g of malic acid (0.1 mol per 100 mol of succinic acid)
5 mol), and reacted at 180 ° C. for 0.5 hour in a nitrogen atmosphere, and then heated to 220 ° C. and reacted for 0.5 hour. Subsequently, under a reduced pressure of 0.5 mmHg.
The polymerization reaction was performed for 5 hours. The obtained polyester was milky white and Mn was 75,300. The melting point is 1
It was 10 ° C. The lactic acid introduction rate by ¹ H-NMR was 6.3 mol per 100 mol of succinic acid.

Examples 1-3 and Comparative Examples 1-2 The aliphatic polyester (A) of Preparation Example 1 was mixed with poly-L-lactic acid (B) (Mn = 100,000) in the formulation shown in Table 1. A film was formed from the composition obtained by kneading with a Brabender, and a tensile test was performed. Table 1 shows the results.

[0037]

[Table 1]

The aliphatic polyester resin of the present invention is not only biodegradable but also has excellent moldability, so that it can be suitably used for various applications.

Claims (12)

(57) [Claims] 1. A copolymer having (a) an aliphatic diol, (b) an aliphatic dicarboxylic acid or a derivative thereof, and (c) a bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof, and having a number average molecular weight of 10,000. An aliphatic polyester composition obtained by melt-blending 99 to 1 parts by weight of an aliphatic polyester (A) having a number average molecular weight of 30,000 or more and 1 to 99 parts by weight of a polylactic acid (B) having a number average molecular weight of 30,000 or more. . 2. The aliphatic polyester (A) is composed of (b) 100 moles of an aliphatic dicarboxylic acid or a derivative thereof, and (a) 100 to 150 moles of an aliphatic diol;
It is obtained by copolymerizing 0.04 to 60 mol of a bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof,
The composition according to claim 1. 3. The aliphatic polyester (A) wherein (c) the bifunctional aliphatic hydroxycarboxylic acid or a derivative thereof has the formula: (Wherein a represents 0 or an integer of 1 or more). 4. The composition according to claim 1, wherein (c) the bifunctional aliphatic hydroxycarboxylic acid or the derivative thereof in the aliphatic polyester (A) is lactic acid. 5. The composition according to claim 1, wherein the aliphatic diol (a) in the aliphatic polyester (A) is 1,4-butanediol. 6. The aliphatic polyester (A) according to claim 1, wherein (b) the aliphatic dicarboxylic acid or a derivative thereof is succinic acid or succinic anhydride, or a mixture thereof with adipic acid. The composition according to Item. 7. When the aliphatic polyester (A) undergoes a polycondensation reaction between (a) an aliphatic diol and (b) an aliphatic dicarboxylic acid or a derivative thereof, (c) a bifunctional aliphatic hydroxycarboxylic acid or The derivative is used in an amount of 0.04 per 100 moles of the aliphatic dicarboxylic acid (b)
The composition according to any one of claims 1 to 6, wherein the composition is obtained by using a catalyst consisting of a germanium compound in the presence of up to 60 moles. 8. A method according to claim 1, wherein
A film using the composition of the above. 9. The method according to claim 1, wherein
Synthetic paper using the composition of the above. 10. The method according to claim 1, wherein:
Filament using the composition described above. 11. The method according to claim 1, wherein:
Nonwoven fabric using the composition described above. 12. The method according to claim 1, wherein:
Blow bottle using the composition described above.