JP2013166906A - Flexible polylactic acid-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film or sheet obtained by forming a polylactic acid-based resin composition into a film through inflation forming, the polylactic acid-based resin composition being excellent in flexibility, stable processability and heat sealability without impairing excellent characteristics possessed by polylactic acid such as transparency and biodegradability.SOLUTION: A flexible polylactic acid-based resin composition (1) comprises a polylactic acid-based resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic-aromatic polyester, where the mixed ratio: (1)=(A)/(B)/(C) is 100=(90-70)/(20-5)/(5-0.1), in terms of mass ratio.

Description

The present invention relates to a soft polylactic acid-based resin composition excellent in flexibility, stable processability and heat sealability without impairing excellent properties such as transparency and biodegradability of polylactic acid.

In recent years, with the growing interest in the environment, films used as garbage bags, plastic bags, and food packaging materials are preferred to be produced from resins that have characteristics such as being biodegradable and made from non-depleted resources. It has become. However, until now, the price of the resin was two to three times as high as that of conventional resin products such as polyolefin such as polyethylene and polypropylene, so that the resin was rarely used as a general packaging material.

Polylactic acid has a lower price of resin due to expansion of production volume and improvement of production technology, uses starch, which is a non-depleted resource, as well as biodegradability, making it practical. Attention has been focused on being an excellent resin, and development in various fields is underway.

Polylactic acid is known to have several advantages when compared to other biodegradable resins. For example, it has a relatively high melting point of about 170 ° C. and excellent heat resistance. Furthermore, transparency is a preferred feature when used as a packaging material.

However, polylactic acid has the drawbacks of being hard and brittle, and since the melt viscosity is low, it is difficult to form a film by inflation processing, and even if it can be formed into a film, the blow ratio cannot be obtained and the film strength is low. Furthermore, there is a drawback that the heat sealability is lacking, and these modifications are required.

As a technique for improving polylactic acid to be soft, it is widely used to include polycaprolactone and aliphatic polyester in the composition. According to this technique, softening can be achieved without impairing the biodegradability characteristic of polylactic acid. However, transparency, which is one of the excellent features of polylactic acid, is lost. (Patent Documents 1 to 3)
JP 2005-036172 A JP-A-2005-330321 JP2011-082149A

In addition, as a technique for maintaining transparency and softening, there is a technique that includes an acrylic block copolymer in the composition, but the biodegradability that is characteristic of polylactic acid is impaired. (Patent Document 4)
JP2007-023145

The present invention is a soft polylactic acid composition comprising a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic aromatic polyester. In addition, the present invention provides a resin composition excellent in flexibility, stable processability, and heat sealability without impairing excellent properties such as transparency and biodegradability of polylactic acid.

Another object is to provide a film or sheet using the soft polylactic acid composition according to the present invention.

As a result of intensive studies to overcome the above-mentioned problems, the present inventor has found that a soft polylactic acid composition in which several raw materials are blended in a balanced manner solves the above problems, and has completed the present invention. .

(1) A soft polylactic acid resin composition according to the present invention comprises a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin that is an aliphatic aromatic polyester ( C) and the mixing ratio of (1) = (A) / (B) / (C) is a mass ratio of 100 = 90-50 / 30-5 / 30-0.1. .

The composition according to the present invention softens without impairing the transparency and biodegradability characteristic of polylactic acid. At the same time, heat sealability, which is also a drawback of polylactic acid, can be improved.

From this, the film or sheet using the soft polylactic acid composition according to the present invention is excellent in transparency, flexibility, and heat sealability, and can be stably molded and processed in the same manner as conventional resins. It can be used for various purposes. In addition, since the biodegradability is not impaired, an environmentally friendly product can be provided.

Details of the present invention will be described below.

(1) A soft polylactic acid resin composition according to the present invention comprises a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin that is an aliphatic aromatic polyester ( C).

The polylactic acid resin contained in the soft polylactic acid resin composition according to the present invention is a polymer obtained by polymerizing lactic acid by an ester bond, and the polymerization is performed by a known method.

The biodegradable resin plasticizer (B) which is a mixed group ester compound contained in the soft polylactic acid resin composition according to the present invention comprises an ester of an aliphatic polybasic acid and at least two kinds of alcohols or ether alcohols. It is a plasticizer.

The biodegradable resin (C) which is an aliphatic aromatic polyester contained in the soft polylactic acid resin composition according to the present invention comprises a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol. A resin obtained by polymerizing an aliphatic aromatic polyester obtained by condensation with a polyfunctional isocyanate.

The soft polylactic acid-based resin composition according to the present invention comprises 90-50% of the above-mentioned polylactic acid-based resin (A), 30-5% of a biodegradable resin plasticizer (B) that is a mixed ester compound, and an aliphatic aromatic A biodegradable resin (C) that is polyester is a soft polylactic acid resin-based composition comprising 30 to 0.01% (mass cost). In any case, the composition is (a), (b), (c) Is 100 parts by weight in total.

The soft polylactic acid-based resin composition according to the present invention includes a biodegradable resin plasticizer (B) that is a mixed ester compound and a biodegradable resin (C) that is an aliphatic aromatic polyester. Without impairing the transparency of lactic acid, the heat sealability, which has been a drawback of polylactic acid resins, is improved.

The soft polylactic acid resin composition according to the present invention includes a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic aromatic polyester. However, calcium carbonate (D), which is an inorganic filler, can also be used for the purpose of preventing blocking. Any of the range of 50 to 0.01% (mass cost) may be used, but preferably 20 to 0.1% in view of transparency.

Originally, talc can be used as an antiblocking agent, but talc acts as a crystal nucleating agent, and a biodegradable resin plasticizer (B), which is a mixed group ester compound, acts unintentionally as a crystallization accelerator. In addition to causing significant shrinkage at times, the soft polylactic acid-based resin composition according to the present invention contains calcium carbonate (D) for the purpose of preventing blocking. Use.

Resin (E) which has biodegradability can also be added to the soft polylactic acid-type resin composition by this invention according to a use. Examples of the biodegradable resin (E) blended in the soft polylactic acid resin composition according to the present invention include aliphatic polyester resins, polycaprolactone resins, caprolactone-butanediol-succinic acid copolymers, and cellulose acetate. Plastic resin, starch-based copolyester resin, starch fatty acid ester resin, polyvinyl alcohol resin, modified PET having biodegradability, polyhydroxybutyrate (PHB) or polyhydroxyvalerate (PHV) or a copolymer thereof (PHVB) Polyhydroxyalkanoate (PHA) which is a copolyester containing poly-3-hydroxybutyric acid, 3-hydroxyhexanoic acid and the like. The blending amount of the biodegradable resin (E) may be any range of 50 to 0.1% (mass cost), but preferably 10 to 0.1% (mass cost) in consideration of transparency. ).

The soft polylactic acid-based resin composition according to the present invention has an ultraviolet ray inhibitor, a light stabilizer, an antifogging agent, an antifoggant, an antistatic agent, a flame retardant, an anti-coloring agent, an antioxidant, and a filler depending on applications. Additives other than the above, such as pigments, can also be added. In any case, it is desirable to add as long as transparency, biodegradability and flexibility are not impaired.

Specific examples of the soft polylactic acid resin composition according to the present invention include Ingeo® manufactured by Nature Works, Inc. as the polylactic acid resin (A). In addition, examples of the biodegradable resin plasticizer (B) that is a mixed group ester compound include Daifati Chemical's Daifati, and further, biodegradable resins (C) that are aliphatic aromatic polyesters include BASF. Examples include Ecoflex made by the company.

Hereinafter, an example of the method for producing the soft polylactic acid resin composition according to the present invention will be described.
First, a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed group ester compound, a biodegradable resin (C) that is an aliphatic aromatic polyester, and in some cases calcium carbonate (an inorganic filler) D) Further, a predetermined amount including a resin (E) having biodegradability is blended and melt-kneaded with a twin-screw kneading extruder to produce pellets. After drying the produced pellet, it forms into a film by an inflation processing machine. The temperature for normal processing during kneading and film formation is in the range of 160 to 200 ° C.

Next, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples and has a wide range of applications. In addition,% display in an Example and a comparative example is all based on mass. The examples were evaluated as follows.

The transparency was evaluated as follows.
A: Transparent.
○: Slightly white and cloudy.
Δ: Milky white
X: It turns white.

The flexibility was evaluated as follows.
A: Very soft.
○: Soft.
Δ: Slightly soft.
X: Hard and easy to cut.

The processability was evaluated as follows.
A: Stable processing is possible.
○: Processing is possible but not stable.
Δ: Processing is possible but production is not possible.
X: Processing is impossible.

Polylactic acid 79%, Daifati 101 20%, Additive 1% by weight blended, fed to twin screw extruder, melt kneaded at 160-200 ° C to produce strands, cooled with water cooling, then cut with a cutter Pellets were produced.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 79%, Daifati 101 20%, Ecoflex 1%, Additive 1% blended by weight blended, fed to twin screw extruder, melt kneaded at 160-200 ° C to make strands and water cooled After cooling, it was cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 79%, Daifati 101 15%, Ecoflex 5%, Additive 1% blended, blended and fed to a twin-screw extruder, melt-kneaded at 160-200 ° C to produce strands, and water-cooled After cooling, it was cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 80.8%, Daifati 101 15%, Ecoflex 3%, additives are blended in a weight blend of 1.2%, supplied to a twin screw extruder, melt-kneaded at 160-200 ° C to produce a strand After cooling with water cooling, the pellets were produced by cutting with a cutter.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Blended with polylactic acid 84.7%, Daifati 101 15%, additive 0.3% by weight, fed to twin screw extruder, melt kneaded at 160-200 ° C to make strands, cooled with water cooling After that, it was cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 84.5%, Daifati 101 12%, Ecoflex 3%, Additives 0.5% blended by weight blended, fed to a twin screw extruder and melt kneaded at 160-200 ° C to produce strands After cooling with water cooling, the pellets were produced by cutting with a cutter.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 82%, Daifati 101 12%, Ecoflex 2%, Additive 4% blended by weight blended, fed to a twin screw extruder and melt kneaded at 160-200 ° C to produce a strand and water cooled After cooling, it was cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Blended with polylactic acid 86.5%, Daifati 101 12%, Ecoflex 1% and additive 0.5% by weight, fed to twin screw extruder and melt kneaded at 160-200 ° C to produce strands After cooling with water cooling, the pellets were produced by cutting with a cutter.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 86.2%, Daifati 101 12%, Ecoflex 0.5%, Additives blended by weight of 1.3%, supplied to twin screw extruder, melt kneaded at 160-200 ° C and strand Was manufactured and cooled with water, and then cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid (86%), Daifati 101 (12%), Ecoflex (0.5%) and additives (1.2%) are blended in a weight blend, supplied to a twin-screw extruder, melt-kneaded at 160-200 ° C to produce a strand. After cooling with water cooling, the pellets were produced by cutting with a cutter.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid (86%), Daifati 101 (10%), Ecoflex (3%), and additive (1%) are blended in a weight blend, supplied to a twin-screw extruder, melt-kneaded at 160-200 ° C to produce a strand, and water-cooled After cooling, it was cut with a cutter to produce pellets.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Polylactic acid 87.5%, Daifati 101 10%, Ecoflex 1%, and additive 1.5% blended by weight blended, fed to a twin screw extruder and melt kneaded at 160-200 ° C to produce strands After cooling with water cooling, the pellets were produced by cutting with a cutter.

The manufactured pellets were placed in an oven set at 80 ° C. and dried for 3 hours to remove moisture.

The produced pellet was formed into a film with an inflation processing machine to produce a film having a thickness of 20 μm.

Table 1 shows the blending ratio, transparency, flexibility, and processability of the resin compositions of Examples 1 to 12.

According to the present invention, the transparency and biodegradability, which are the characteristics of polylactic acid, can be softened without impairing it, and at the same time, the heat sealability, which is also a drawback of polylactic acid, can be improved.

In addition, since the disadvantage of polylactic acid, which is hard and brittle, is modified, it is possible to stably process a film by film formation using an inflation processing machine, which has been difficult in the past.

Therefore, the film and sheet using the soft polylactic acid composition according to the present invention and the soft polylactic acid composition according to the present invention are not limited to fields such as trash bags, plastic bags, and compost bags that use biodegradable resins. It can be used in a wide range of applications as food packaging materials such as vegetables and fruits that require transparency, as general packaging materials such as stationery, and as wrapping materials such as flowers and laminating materials with paper and nonwoven fabrics.

The present invention comprises a polylactic acid-based resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic aromatic polyester, and has a transparent property of polylactic acid. The present invention provides a soft polylactic acid-based film excellent in flexibility, stable processability and heat sealability without impairing excellent properties such as properties and biodegradability.

Another object of the present invention is to provide a film or sheet obtained by forming the soft polylactic acid resin composition according to the present invention into a film by inflation molding.

(1) A soft polylactic acid resin composition according to the present invention comprises a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin that is an aliphatic aromatic polyester ( C), and the mixing ratio of (1) = (A) / (B) / (C) is mixed at a mass ratio of 100 = 90 to 70/20 to 5/5 to 0.1. .

Therefore, the film or sheet obtained by forming the soft polylactic acid resin composition according to the present invention into a film by inflation molding has excellent transparency, flexibility, and heat sealability. Can be used for various purposes.

The biodegradable resin plasticizer (B) that is a mixed group ester compound contained in the soft polylactic acid resin composition according to the present invention is a plasticizer made of benzylmethoxyethoxyethyl adipate.

The soft polylactic acid resin composition according to the present invention comprises 90 to 70% of the above polylactic acid resin (A), 20 to 5% of a biodegradable resin plasticizer (B) that is a mixed ester compound, and an aliphatic aromatic. A biodegradable resin (C) that is a polyester is a soft polylactic acid resin-based composition composed of 5 to 0.1% (both mass ratios), and the composition is (a), (b), ( c) is 100 parts by weight in total.

The soft polylactic acid-based resin composition according to the present invention includes a biodegradable resin plasticizer (B) that is a mixed ester compound and a biodegradable resin (C) that is an aliphatic aromatic polyester. Without impairing the transparency of lactic acid, the heat sealability, which has been a drawback of polylactic acid-based films, is improved.

The soft polylactic acid resin composition according to the present invention includes a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic aromatic polyester. ) Calcium carbonate (D) can also be used as an inorganic filler for the purpose of preventing blocking. The mass ratio may be any of 30 to 0.1%, but preferably 10 to 0.5% in consideration of transparency.

Claims (7)

A soft polylactic acid resin composition comprising a polylactic acid resin (A), a biodegradable resin plasticizer (B) that is a mixed ester compound, and a biodegradable resin (C) that is an aliphatic aromatic polyester The biodegradable resin plasticizer (B) which is a mixed group ester compound is a plasticizer comprising an ester of an aliphatic polybasic acid and at least two kinds of alcohols or ether alcohols. Soft polylactic acid resin composition An aliphatic aromatic polyester, which is a biodegradable resin (C), is a polyfunctional isocyanate obtained by condensing a dicarboxylic acid component composed of adipic acid and terephthalic acid and a diol component composed of 1,4-butanediol. The soft polylactic acid-based resin composition according to claim 1, which is a resin polymerized with Polylactic acid resin (A) 90-50%, biodegradable resin plasticizer (B), which is a mixed group ester compound, 30-5%, biodegradable resin (Aliphatic aromatic polyester) C) Soft polylactic acid resin composition comprising 30 to 0.01% (mass cost) The inorganic filler (D) added to the polylactic acid resin (A), the biodegradable resin plasticizer (B) that is a mixed ester compound, and the biodegradable resin (C) that is an aliphatic aromatic polyester is carbonic acid. 5. The soft polylactic acid resin composition according to claim 1, wherein the composition is calcium and 0.01 to 50% (mass cost) is blended. Biodegradable resin (E) added to polylactic acid resin (A), biodegradable resin plasticizer (B) which is a mixed ester compound, and biodegradable resin (C) which is an aliphatic aromatic polyester The polybutylene succinate resin and the polybutylene succinate adipate resin are blended in an amount of 1 to 50% by weight, and the soft polylactic acid resin composition according to any one of claims 1 and 4 Biodegradable added to polylactic acid resin (A), biodegradable resin plasticizer (B) which is a mixed group ester compound, biodegradable resin (C) which is an aliphatic aromatic polyester (D), and inorganic filler (D) 6. The resin (E) having a property is a polybutylene succinate resin or a polybutylene succinate adipate resin, and 1 to 50% (mass cost) is blended. Soft polylactic acid resin composition