JP2005239978A - Biodegradable resin composition and plasticizer for biodegradable resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable resin composition excellent in flexibility and a plasticizer for the biodegradable resin capable of imparting excellent compatibility and flexibility. <P>SOLUTION: This biodegradable resin composition contains 100 pts.wt. aliphatic-aromatic polyester-based resin and 25-200 pt.wt. ester-based plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component, and selected from a group consisting of a benzoic acid ester, an alkylbenzyl phthalate and a dialkoxyalkyl phthalate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a biodegradable resin composition having extremely excellent flexibility and a plasticizer for a biodegradable resin that imparts excellent compatibility and flexibility.

Conventionally, resins with excellent flexibility and durability, such as soft vinyl chloride resin, polyethylene, and polypropylene, have been used for packaging materials such as magazines, foods, and bags such as plastic bags and garbage bags. Since it is hardly decomposed in the environment, it is a social problem when left in nature.
On the other hand, biodegradable resins that do not decompose and accumulate in nature are gaining in demand and are being actively researched and are being put to practical use in many applications.

Among the biodegradable resins, polyester resins that have attracted attention in recent years are broadly classified into succinates such as polylactic acid, polybutylene succinate, polycaprolactone, and aliphatic-aromatic polyesters. There are seeds, but the physical properties of each resin, such as transparency, resin hardness, compatibility with additives, etc., are very different.
Among them, polylactic acid, which is one of biodegradable resins, has recently been manufactured in large quantities and at low cost, and its use is expected to be expanded. Has also been proposed (see, for example, Patent Document 1).

However, polylactic acid is inferior in flexibility and impact resistance because the properties of the resin itself are similar to those of hard polystyrene resin, so the level of flexibility is low even when a plasticizer is added, and flexibility is required. It is hard to say that it is suitable for film and packaging materials.
On the other hand, succinates, polycaprolactones, and aliphatic-aromatic polyesters are relatively flexible resins that are used in packaging materials such as garbage bags and foods. The level of flexibility required for vinyl resins and the like has not been reached, and further flexibility is required.

  For example, a technique relating to a biodegradable film in which a composition obtained by adding a plasticizer to a three-component resin composed of an aliphatic-aromatic polyester, an aliphatic polyester resin, and a polycaprolactone resin has been proposed (for example, a patent) Reference 2). However, if the added amount of the plasticizer exceeds 20% by weight, the plasticizer bleeds out, so that sufficient flexibility cannot be achieved.

Moreover, the film which consists of a composition which mix | blended the plasticizer and the inorganic filler with the polylactic acid and the aliphatic-aromatic polyester-type resin is proposed (for example, refer patent document 3). However, in the plasticizer described in this publicly known document, the amount of plasticizer added is limited, and it is a fact that a film having sufficient flexibility has not been obtained.
JP 2000-136300 A JP 2003-201351 A JP 2002-327107 A

  It is an object of the present invention to provide an excellent biodegradable resin composition and a biodegradable resin plasticizer that imparts excellent compatibility and flexibility.

  In order to obtain a biodegradable resin composition having flexibility similar to that of conventional polyethylene resins and vinyl chloride resins, the present inventors have conducted intensive studies on combinations of each resin type and various plasticizing substances. It has been found that when a combination of a resin type and a plasticizer, that is, using an aliphatic-aromatic polyester resin and a specific plasticizer, a large amount of plasticizer can be added, and an extremely flexible resin composition can be obtained. The present invention has been achieved.

That is, the present invention
1. 1. A biodegradable resin composition comprising an aliphatic-aromatic polyester resin and an ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component. The ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component is at least one plasticizer selected from the group consisting of benzoic acid esters, alkylbenzyl phthalates, and dialkoxyalkyl phthalates. 2. The biodegradable resin composition as described in 1 above, wherein 1 or 2 above, wherein the content of the ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component with respect to 100 parts by weight of the aliphatic-aromatic polyester resin is 25 parts by weight to 200 parts by weight. 3. Biodegradable resin composition as described in 2. 4. A biodegradable resin composition comprising a biodegradable resin and a plasticizer, wherein the 100% modulus value is 6.0 MPa or less. Plasticizer for aliphatic-aromatic polyester resin comprising at least one compound represented by the following general formulas (1) to (4)

(In the formula, R ¹ represents a linear or branched alkylene group having 2 to 4 carbon atoms, and n represents an integer of 2 to 5)

(Wherein R ² represents a linear or branched alkylene group having 2 to 9 carbon atoms)

Wherein R ³ is a linear or branched alkyl group having 4 to 11 carbon atoms, 3- (butyryloxy)
-1-isopropyl-2,2-dimethylpropyl group or 3- (butyryloxy) -4-methyl-2,2-dimethylpentyl group)

(Wherein R ⁴ and R ⁶ each independently represents a linear or branched alkylene group having 2 to 4 carbon atoms, R ⁵ and R ⁷ each independently represents an alkyl group having 1 to 4 carbon atoms, m And l each independently represents an integer of 1 to 3)
6). The compound represented by the general formula (1) is diethylene glycol dibenzoate or dipropylene glycol dibenzoate, and the compound represented by the general formula (2) is 1,2-butylene glycol dibenzoate or 2,2-dimethyl-1 , 3-propylene glycol dibenzoate, and the compound represented by the general formula (3) is butylbenzyl phthalate, 2-ethylhexylbenzyl phthalate, isononylbenzyl phthalate, 3- (butyryloxy) -1-isopropyl phthalate -2,2-dimethylpropylbenzyl or 3- (butyryloxy) -4-methyl-2,2-dimethylpentylbenzyl phthalate, and the compound represented by the general formula (4) is bis (butoxyethyl) phthalate, Bis (butoxyethoxyethyl) phthalate or bis (butoxy phthalate) Aliphatic according to the 5 ethoxy ethoxyethyl) - aromatic polyester resin for plasticizer 7. The plasticizer for aliphatic-aromatic polyester resins according to 5 or 6 above, wherein the aliphatic-aromatic polyester resin is a biodegradable resin.

  ADVANTAGE OF THE INVENTION By this invention, the biodegradable resin composition excellent in the softness | flexibility which uses an aliphatic-aromatic polyester resin as a resin component can be provided. In addition, it is possible to provide a plasticizer that is compatible with an aliphatic-aromatic polyester-based resin that is a biodegradable resin and has excellent plasticization efficiency.

Hereinafter, the present invention will be described in more detail.
<Biodegradable resin composition>
The aliphatic-aromatic polyester resin in the present invention can be obtained by dehydration condensation of an aliphatic diol, an aliphatic dibasic acid and an aromatic dibasic acid, but the production method is not particularly limited.

  Specific examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol and the like. These can be used alone or in combination of two or more. Among these, ethylene glycol and 1,4-butylene glycol are preferable, and 1,4-butylene glycol is more preferable.

Examples of the aliphatic dibasic acid include succinic acid, maleic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and the like, and these can be used alone or in combination of two or more. Of these, succinic acid and adipic acid are preferred.
Examples of the aromatic dibasic acid include phthalic acid, isophthalic acid, terephthalic acid and the like, and these can be used alone or in combination of two or more. Of these, terephthalic acid is preferred.

Combinations of aliphatic diols with aliphatic dibasic acids and aromatic dibasic acids include, for example, ethylene glycol / succinic acid / terephthalic acid, ethylene glycol / adipic acid / terephthalic acid, 1,4-butylene glycol / succinic acid / terephthalic acid. 1,4-butylene glycol / adipic acid / terephthalic acid, and the like.
The ratio of the aliphatic dibasic acid to the aromatic dibasic acid is 1.0 / 0.02 to 1.0 / 5.0, preferably 1.0 / 0.05 to 1.0 / 2. 0.

As the characteristics of the obtained resin, those having a melting point of 100 ° C. to 120 ° C. and a glass transition temperature of −10 ° C. or less are suitable.
Specific examples of the aliphatic-aromatic polyester resin include “ECOFLEX” manufactured by BASF, “EASTAR BIO” manufactured by FASTMAN CHEMICAL, “BIOMAXS” manufactured by DuPONT, and the like.

The biodegradable resin composition of the present invention comprises the above aliphatic-aromatic polyester resin and a plasticizer as essential components.
In the resin composition of the present invention, 25 to 200 parts by weight of an ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component is contained with respect to 100 parts by weight of the aliphatic-aromatic polyester resin. In a preferred embodiment, the plasticizer can be contained in an amount of preferably 28 parts by weight or more, more preferably 45 parts by weight or more, and preferably 180 parts by weight or less.

If the added amount of the plasticizer is small, the plasticizing effect is insufficient and flexibility cannot be imparted. On the other hand, when the amount is excessively large, it causes bleeding out of the plasticizer.
According to the combination of the resin and the plasticizer of the present invention, it is possible to add a larger amount of plasticizer than the amount of plasticizer conventionally considered, and as a result, the biodegradability is extremely flexible and could not be obtained conventionally. A resin composition can be obtained.

  Conventionally, in conventional biodegradable resin compositions such as polylactic acid-based resins and aliphatic-aromatic polyester-based resins, the amount of plasticizer added is usually 3 to 20 with respect to 100 parts by weight of the resin. However, according to the combination of the specific resin of the present invention and the specific plasticizer, it is surprisingly 25 parts by weight or more, for example, 100 parts by weight of the aliphatic-aromatic polyester-based resin. 100 parts by weight of a plasticizer can be added, and by adding such a large amount of plasticizer, it is possible to obtain a resin composition exhibiting further excellent flexibility.

In the resin composition of the present invention thus obtained, those having the physical properties in the specific ranges shown below are particularly useful.
The 100% modulus value which is one of the indices of flexibility is 6.0 MPa or less, preferably 4.0 MPa or less. It shows that it is so flexible that this value is low. Although the minimum is not specifically limited, Preferably it is about 0.5 MPa.

Moreover, the resin composition which has the following characteristic values is excellent in the softness | flexibility, and is preferable.
Those having a tensile strength at break of 2 to 30 MPa, preferably 5 to 25 MPa.
Those having a tensile elongation of 300 to 1000%, particularly preferably 400 to 950%.
The 100% modulus value, the tensile strength at break, and the elongation referred to in the present invention are the stress when the No. 2 type test piece is pulled at a rate of 200 mm / min by autograph according to JIS K6723 and the elongation reaches 100% ( 100% modulus value), stress at break (tensile rupture strength: tensile strength), and elongation (tensile elongation).

The method for blending the plasticizer with the biodegradable resin is not particularly limited, and a conventionally known method can be employed.
For example, after mixing the resin and the plasticizer at a predetermined ratio, the mixture is kneaded with a known kneader such as a twin screw extruder, single screw extruder, various kneaders, and pelletized to obtain a homogeneous composition. Obtainable. Further, the obtained composition can be molded by various known molding methods such as an extrusion molding machine, an injection molding machine, a vacuum molding machine, and an inflation molding machine to obtain a desired product.

If necessary, the biodegradable resin composition of the present invention may contain other components that are usually added to the biodegradable resin composition as long as the effects of the present invention are not impaired. Examples of such components include modifiers, crystal nucleating agents, fragrances, antibacterial agents, pigments, dyes, weathering agents, lubricants, antistatic agents, stabilizers, fillers, reinforcing agents, antiblocking agents, flame retardants, and the like. Can be mentioned.
Moreover, it is also possible to add a resin component other than the specific resin and a plasticizer component other than the specific plasticizer of the present invention within a range not impairing the objects and effects of the present invention.

<Plasticizer for biodegradable resin>
The resin composition of the present invention is characterized by using a specific plasticizer, that is, an ester plasticizer that essentially includes an aromatic carboxylic acid component and an aliphatic alcohol component, in combination with a specific resin.
As the ester plasticizer essentially comprising an aromatic carboxylic acid component and an aliphatic alcohol component, benzoic acid esters, particularly preferably esters of benzoic acid and aliphatic polyhydric alcohols, phthalic acid and aliphatic alcohols, and An ester with an aromatic alcohol, preferably an alkylbenzyl phthalate, and an ester of a phthalic acid with an aliphatic alcohol, preferably a dialkoxyalkyl phthalate are preferable. Of these, particularly preferred are esters of benzoic acid and aliphatic dihydric alcohols.

  A benzoic acid ester which is a kind of plasticizer used in the present invention is an ester of benzoic acid and an aliphatic polyhydric alcohol, preferably a dihydric alcohol benzoic acid represented by the general formula (1) or (2). Ester. Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propylene glycol, and 2,2-dimethyl. Examples include propylene glycol, 3-methyl-1,5-bentanediol, 1,6-hexanediol, 1,9-nonanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol. One or a mixture of two or more thereof can be used, and in particular, diethylene glycol, dipropylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, 2,2-dimethyl-1, - Propylene glycol is preferred.

In order to produce the benzoic acid ester, conventionally known production methods can be employed. For example, by carrying out an esterification reaction at 180-200 ° C. with an azeotropic solvent of water with an excess of benzoic acid and an equivalent of the dihydric alcohol, and then neutralizing and removing the excess benzoic acid with an alkali. The desired benzoic acid ester can be obtained.
An ester of benzoic acid, an aliphatic alcohol and an aromatic alcohol, which is one of the plasticizers used in the present invention, is preferably an alkylbenzyl phthalate represented by the general formula (3). As the monohydric alcohol constituting the alkyl of n-butanol, n-hexanol, n-octanol, 2-ethylhexanol, isononal, n-decanol, undecanol, 3- (butyryloxy) -1-isopropyl-2,2- Examples thereof include dimethylpropanol, 3- (butyryloxy) -4-methyl-2,2-dimethylpentanol, and one or a mixture of two or more thereof can be used. Particularly, n-butanol, 2-ethylhexanol, Isononanol, 3- (butyryloxy) -1-isopropyl-2,2- Methyl propanol, 3- (butyryloxy) -4-methyl-2,2-dimethyl-pentanol are preferred.

In order to produce the alkylbenzyl phthalate, a conventionally known production method can be employed. For example, monoalkyl phthalate can be obtained from phthalic anhydride and alcohol, neutralized with alkali, and then reacted with benzyl chloride to obtain the target alkylbenzyl phthalate.
Among the esters of phthalic acid and aliphatic alcohols, which are a kind of plasticizer used in the present invention, preferred dialkoxyalkyl phthalates represented by the general formula (4) are phthalic acid esters of monohydric alcohols. Examples of monohydric alcohols include methoxyethanol, ethoxyethanol, propoxyethanol, butoxyethanol, methoxypropanol, ethoxypropanol, propoxypropanol, butoxypropanol, methoxybutanol, ethoxybutanol, propoxybutanol, butoxybutanol, methoxyethoxyethanol, ethoxyethoxy Ethanol, propoxyethoxyethanol, butoxyethoxyethanol, ethoxyethoxyethoxyethanol, butoxyethoxyethoxyethanol, ethoxybutoxy Butoxy butanol, butoxyethanol butoxy butoxy butanol and the like, may be used the one or two or more thereof, in particular butoxyethanol, butoxy ethoxy ethanol, butoxy ethoxy ethoxy ethanol preferred.

In order to produce the dialkoxyalkyl phthalate, a conventionally known production method can be employed. For example, after reacting phthalic anhydride and phthalic anhydride in excess of an equivalent amount in the presence of an organic titanate ester as a catalyst at 180 to 220 ° C., the product is purified by distillation or the like, and the desired dialkyl phthalate Can be obtained.
Specific examples of the ester plasticizer having such an aromatic carboxylic acid component and an aliphatic alcohol component include “JP120”, “OB ₂ P”, and “D180” manufactured by J. Plus.
, “DBMP”, and Fellow “BBP”.

  Many of these plasticizers have biodegradability as the plasticizer itself and are preferable.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example, this invention is not limited by a following example, unless the summary is exceeded.
1. Compounding ingredients (1) Aliphatic-aromatic polyester resin (A)
Product name: Ecoflex (2) Plasticizer (B)

2. Evaluation Method Preparation of Test Piece Resin A and plasticizer B were mixed with a Henschel mixer (80 ° C.), and the plasticizer was impregnated into the resin to obtain a mixture. Subsequently, this was kneaded and granulated under a temperature condition of 160 ° C. using a same-direction twin-screw extruder (caliber 30 mm, L / D = 30) to obtain pellets. The obtained pellets were molded into a sheet having a thickness of 0.3 mm by a press molding machine (temperature 180 ° C., pressure 150 kgf / cm ² , pressing time 3 minutes).

(1) Tensile test JIS K6723 type 2 test piece was pulled at a rate of 200 mm / min by autograph, and the stress when the elongation reached 100% (100% M), the stress at the time of cutting (tensile strength) and the elongation Was measured.
(2) Surface State A 10 cm × 10 cm sample was prepared from the obtained press sheet, and the surface state after observing at 25 ° C. and a relative humidity of 50% for 1 week was observed.

○: The plasticizer is not bleeding at all. Δ: The plasticizer is slightly bleeding. ×: The plasticizer is markedly bleeding. Example of creating test pieces and evaluation results (1) Examples 1 to 10
A test piece was prepared from the blending ratios shown in Table-2 using the above-mentioned method using BSF Ecoflex manufactured by BASF as an aliphatic-aromatic polyester resin and B-1 to B-5 shown in Table-1 as plasticizers. ,evaluated. The results are shown in Table-2.

(2) Comparative Examples 1-4
No plasticizer was used (Comparative Example 1), or B-6 to B-8 in Table 1 were used as plasticizers in the amounts shown in Table 2 (Comparative Examples 2 to 4). Test pieces were prepared and evaluated in the same manner as in 1-10. The results are shown in Table-2.
Comparative Examples 2 to 4 were not evaluated because the plasticizer bleedout was remarkable.

Claims (7)

  A biodegradable resin composition comprising an aliphatic-aromatic polyester resin and an ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component.   The ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component is at least one plasticizer selected from the group consisting of benzoic acid esters, alkylbenzyl phthalates, and dialkoxyalkyl phthalates. The biodegradable resin composition according to claim 1.   The content of the ester plasticizer having an aromatic carboxylic acid component and an aliphatic alcohol component with respect to 100 parts by weight of the aliphatic-aromatic polyester resin is 25 parts by weight or more and 200 parts by weight or less. Item 3. The biodegradable resin composition according to Item 1 or 2.   A biodegradable resin composition comprising a biodegradable resin and a plasticizer, wherein the 100% modulus value is 6.0 MPa or less. A plasticizer for an aliphatic-aromatic polyester resin comprising at least one of the compounds represented by the following general formulas (1) to (4).

(In the formula, R ¹ represents a linear or branched alkylene group having 2 to 4 carbon atoms, and n represents an integer of 2 to 5)

(Wherein R ² represents a linear or branched alkylene group having 2 to 9 carbon atoms)

(In the formula, R ³ is a linear or branched alkyl group having 4 to 11 carbon atoms, 3- (butyryloxy)-
1-isopropyl-2,2-dimethylpropyl group or 3- (butyryloxy) -4-methyl-2,2-dimethylpentyl group)

(Wherein R ⁴ and R ⁶ each independently represents a linear or branched alkylene group having 2 to 4 carbon atoms, R ⁵ and R ⁷ each independently represents an alkyl group having 1 to 4 carbon atoms, m And l each independently represents an integer of 1 to 3) The compound represented by the general formula (1) is diethylene glycol dibenzoate or dipropylene glycol dibenzoate, and the compound represented by the general formula (2) is 1,2-butylene glycol dibenzoate or 2,2-dimethyl-1 , 3-propylene glycol dibenzoate, and the compound represented by the general formula (3) is butylbenzyl phthalate, phthalic acid 2
-Ethylhexylbenzyl, isononylbenzyl phthalate, 3- (butyryloxy) -1-isopropyl-2,2-dimethylpropylbenzyl phthalate or 3- (butyryloxy) -4-methyl-2,2-dimethylpentylbenzyl phthalate 6. The aliphatic group according to claim 5, wherein the compound represented by the general formula (4) is bis (butoxyethyl) phthalate, bis (butoxyethoxyethoxyethyl) phthalate or bis (butoxyethoxyethoxyethyl) phthalate. -Plasticizer for aromatic polyester resin.   The plasticizer for an aliphatic-aromatic polyester resin according to claim 5 or 6, wherein the aliphatic-aromatic polyester resin is a biodegradable resin.