JP2011084704A - Modification of biodegradable resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable resin composition imparting flexibility to a biodegradable resin without exerting any effect to biodegradability which (1) can be economically produced in the range of molding conditions of a general-purpose resin by means of a general-purpose molding processing machine, and (2) is suitable for a wide range of uses from hard and semi-hard products to soft products. <P>SOLUTION: The resin composition comprises 3 to 80 pts.wt. of acrylic-styrene-based copolymer including ≥4 C alkylacrylate of ≥30% and 3 to 80 pts.wt. of a plasticizer for resin, per 100 pts.wt. of the biodegradable resin. Therein, the plasticizer for resin is a conductive or antistatic plasticizer having volume resistivity and/or surface resistivity of ≤10 Ωcm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

Detailed Description of the Invention

The present invention relates to a modification for the purpose of improving the moldability of biodegradable resins and expanding applications.

In recent years, environmental pollution problems caused by resins, such as marine pollution and soil pollution, have been highlighted. As countermeasures, biodegradable resins and naturally disintegrating resins have been proposed and evaluated on the market. However, the current situation is that the spread of the product has been delayed due to problems in quality and moldability and poor usability.
The problems in quality and performance are as follows: (1) The molding processing width is narrow, and economical production is difficult with a general-purpose molding machine.
(2) There is no flexibility in terms of quality, and it is hard and brittle, so it is limited in use.
(3) Modification by adding a large amount of other resin or the like impairs biodegradability.
Such problems have been pointed out.

Problems to be solved by the present invention

The present invention gives the biodegradable resin flexibility and does not significantly affect biodegradability,
(1) To provide a biodegradable resin composition that can be produced economically within a range of molding conditions for a general-purpose resin using a general-purpose molding machine.
(2) To provide a biodegradable resin composition suitable for a wide range of applications from hard to semi-rigid and soft products.

Means to solve the problem

As a result of many years of research to achieve the object, the present inventor has found that a resin comprising an acrylic-styrene copolymer containing 30% or more of an alkyl acrylate having 4 or more carbon atoms with respect to a biodegradable resin and a plasticizer for the resin. The present inventors have found that the composition solves the above-mentioned problems and completed the present invention.
The present invention has the following configuration.
(1) 3 to 80 parts by weight, preferably 5 to 50 parts by weight of a% acrylic-styrene copolymer containing 30 or more parts of alkyl acrylate having 4 or more carbon atoms, relative to 100 parts by weight of biodegradable resin, plasticizer for resin A biodegradable resin composition comprising 3 to 50 parts by weight, preferably 5 to 50 parts by weight.
(2) The resin composition according to (1), wherein the biodegradable resin is polylactic acid.
(3) The plasticizer for resin is a conductive or antistatic plasticizer having a volume resistivity and / or surface resistivity of 10 (Ω · cm) or less, as described in (1) Biodegradable resin composition.

The invention's effect

For example, in the case of polylactic acid, the melting point is usually 170 ° C. or higher, and a molded product cannot be produced unless the molding process conditions are 180 ° C. or higher. However, the present resin composition can be molded at 150 ° C. Therefore, it can be sufficiently molded by general-purpose steam heating and oil heating molding machines. Moreover, since this composition can adjust a softness | flexibility according to the quantity of a plasticizer, it can expand | deploy to a hard product, a semi-rigid product, and a soft product according to a use.

Examples of the biodegradable resin used in the present invention include chemical synthetic products such as polylactic acid, polycaprolactone, and aliphatic polyester, microbial synthetic products such as microbial polysaccharides, natural polymers such as chitosan / cellulose, and the like. .

  The acrylic-styrene copolymer containing 30% by weight or more of alkyl acrylate having 4 or more carbon atoms used in the present invention is 60 to 70% by weight of acrylic acid or methacrylic acid, and 30 to 40% by weight of alkyl acrylic acid having 4 or more carbon atoms. Styrene, 2 to 5% by weight. When each component is out of this range, the plasticizer absorbability is remarkably lowered.

The plasticizer is a commonly used plasticizer for resins. For example, phthalic acid plasticizers such as DOP, DINP and TOTM, fatty acid plasticizers such as DOA and DINA, plasticizers derived from vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, polyester plasticizers, TCP And phosphite plasticizers such as TPP.
These plasticizers are added in an amount of 3 to 80 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the biodegradable resin. Less than 3 parts by weight is less effective, and more than 80 parts by weight is not practical because of quality problems.

  Among these plasticizers, conductive or antistatic plasticizers having a volume resistivity and / or surface resistivity of 10 (Ω · cm) or less have a very high affinity for biodegradable resins and have a plasticizing effect. Is remarkable. As such conductive or antistatic plasticizers, adipic acid-based, polyester-based, and phthalic acid-based ones are commercially available, and any of them exhibiting the above resistance value is effective. However, the lower the resistance value, the greater the effect.

  The resin composition of the present invention is mixed using an ordinary mixing apparatus such as a Henschel mixer (trade name), a super mixer, a ribbon blender, etc., and directly or granulated, and then an injection molding method, an extrusion molding method, a blow molding method. It is used for the production of the desired molded product by a calendar molding method or the like.

[Comparative Examples 1 and 2]
3 parts by weight of acrylic resin processing aid (Mitsubishi Rayon, Metabrene P530) and 100% by weight of alkyl acrylate having 4 or more carbon atoms are included with respect to 100 parts by weight of polylactic acid (Mitsui Chemicals Lacia H100J) 3 parts by weight of an acrylic-styrene copolymer (Mitsubishi Rayon), 3 parts by weight of plasticizer for resin (DOP), and appropriate amounts of antioxidant and lubricant were weighed and mixed, and the temperature was set to 160 to 180 ° C. A sheet having a thickness of about 0.5 mm was prepared by kneading with an 8-inch roll. The sheet was measured for hardness with a JISA hardness meter, and with a shopper type tensile tester for tensile strength and elongation. The results are shown in Table 1. As can be seen, the processing temperature is 180 ° C., the resin temperature is 175 ° C., and the hardness (JISA) is 95 ° C. or more, which is equivalent to hard when it is a vinyl chloride resin.

[Examples 1 to 3]
100 parts by weight of polylactic acid used in Comparative Examples 1 and 2, and 10 to 40 parts by weight of the acrylic-styrene copolymer used in Comparative Example, 10 to 40 parts by weight of plasticizer for resin (DOP), Then, 10 parts by weight of epoxidized soybean oil and appropriate amounts of an antioxidant and a lubricant were weighed and mixed, and a film was formed in the same manner as in the comparative example using an 8-inch roll set at a temperature of 150 to 170 ° C. This sheet was measured in the same manner as in the comparative example. The results are shown in Table 1. As can be seen, the processing temperature and the resin temperature decreased by 10 to 20 ° C., and the hardness (JISA) also decreased to 90 to 95 degrees, corresponding to a semi-rigid equivalent in the case of a vinyl chloride resin.

[Examples 4 and 5]
100 parts by weight of the polylactic acid used in Comparative Examples 1 and 2, and 40 to 60 parts by weight of the acrylic-styrene copolymer used in the Comparative Example, conductive plasticizer (manufactured by Adeka, LV808, specific volume) Resistance value 8.2 × 10) 40 to 80 parts by weight and appropriate amounts of an antioxidant and a lubricant were weighed and mixed, and a film was formed in the same manner as in the comparative example with an 8-inch roll set at a temperature of 150 to 170 ° C. This sheet was measured in the same manner as in the comparative example. The results are shown in Table 1. As can be seen, the processing temperature and the resin temperature were reduced by 10 to 20 ° C., and the hardness (JISA) was also reduced to 80 to 85 degrees, corresponding to a soft equivalent when using a vinyl chloride resin.

[Comparative Example 3]
100 parts by weight of the conductive plasticizer used in Examples 4 and 5 with respect to 100 parts by weight of the polylactic acid used in Comparative Examples 1 and 2 and 40 parts by weight of the acrylic-styrene copolymer used in Comparative Examples. Parts and appropriate amounts of antioxidants and lubricants were weighed and mixed, and a film was formed in the same manner as in Comparative Examples 1 and 2 using an 8-inch roll set at a temperature of 150 to 160 ° C. However, the melt on the roll was too soft as it was, and could not be drawn out to the sheet. Therefore, the film was formed by reducing the roll temperature to 140 ° C. Then, the same physical properties were measured, but if the sample was allowed to stand at room temperature for 2 to 3 days after the measurement, the plasticizer was blown out on the surface. The results are shown in Table 1.

Claims (3)

Biodegradability comprising 3 to 80 parts by weight of an acrylic-styrene copolymer containing 30% by weight or more of alkyl acrylate having 4 or more carbon atoms and 3 to 80 parts by weight of a plasticizer for resin with respect to 100 parts by weight of biodegradable resin. Resin composition. The biodegradable resin composition according to claim 1, wherein the biodegradable resin is polylactic acid. The biodegradability according to claim 1, wherein the plasticizer for resin is a conductive or antistatic plasticizer having a volume resistivity and / or surface resistivity of 10 (Ω · cm) or less. Resin composition.