JP2011225643A - Biodegradable resin composition, biodegradable film and biodegradable molded item - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable resin composition that gives out little smell when processed and affords a biodegradable film and a biodegradable molded item that exhibit excellent physical properties and elute little amount of biodegradable components.SOLUTION: The biodegradable resin composition comprises (A) a thermoplastic synthetic resin, (B) an inorganic filler and (C) biodegradable organic matter, where the compounded amount of the component (A) is at most 49 mass% based on the whole amount of the composition and the compounding ratio of the component (B) to the component (C) ((B)/(C)) is within the range of 3/7 to 7/3 in terms of mass ratio.

Description

  The present invention relates to a biodegradable resin composition, a biodegradable film comprising the composition, and a biodegradable molded article comprising the composition.

At present, plastic products are widely used all over the world, while the disposal of waste plastics is a problem. For example, it is said that it takes about 400 years to completely decompose plastic when it is disposed of in soil. Incineration of plastic often generates toxic gases, leading to air and soil contamination. Furthermore, it has been pointed out that carbon dioxide generated by incineration promotes global warming.
Therefore, various biodegradable plastics that decompose naturally after disposal have been developed. For example, instead of a general plastic material, a biodegradable starch resin using 40 to 80% starch as a main raw material has been proposed (see Patent Document 1). In addition, a biodegradable sheet comprising a starch resin containing 70% by weight or more of starch and containing starch and olefin resin as main components has been proposed (see Patent Document 2).

JP-A-9-296076 Japanese Patent No. 3832668

  However, the container made of starch resin described in Patent Document 1 is not sufficient in physical properties such as rigidity and impact resistance as compared with general plastic products, and also has a problem of odor during processing. Furthermore, when this container is sterilized, starch may be eluted. The biodegradable sheet described in Patent Document 2 has the same problem.

  An object of the present invention is to provide a biodegradable resin composition capable of producing a biodegradable film or a biodegradable molded article having little odor during processing, excellent physical properties, and little biodegradable component elution. .

In order to solve the above-described problems, the present invention provides the following biodegradable resin composition, biodegradable film, and biodegradable molded article.
(1) (A) A thermoplastic synthetic resin, (B) an inorganic filler, and (C) a biodegradable organic substance are blended, and the blending amount of the component (A) is 49% by mass based on the total amount of the composition. The biodegradation characterized in that the blending ratio ((B) / (C)) of the component (B) and the component (C) is in the range of 3/7 to 7/3 by mass ratio. Resin composition.
(2) The biodegradable resin composition according to the above (1), wherein the component (A) is a polyolefin resin.
(3) In the biodegradable resin composition as described in (1) or (2) above, the component (B) is talc, calcium carbonate, clay, precipitated barium sulfate, silica, kaolin, diatomaceous earth, silicic acid. A biodegradable resin composition, which is at least one selected from calcium, mica, alumina, aluminum sulfate, calcium sulfate, magnesium carbonate, carbon fiber, glass fiber, glass sphere, graphite, and zeolite.
(4) In the biodegradable resin composition according to any one of (1) to (3), the component (C) is at least one selected from starch, cellulose, polylactic acid, and casein. A biodegradable resin composition characterized by being a seed.
(5) The biodegradable resin composition according to any one of (1) to (4) above, further comprising (D) a binder component. Composition.
(6) In the biodegradable resin composition according to the above (5), the component (D) is at least selected from liquid paraffin, metal soap, silicone, side chain crystalline polyolefin, stearic acid, and polyglutamic acid. A biodegradable resin composition characterized by being one type.
(7) A biodegradable film produced using the biodegradable resin composition according to any one of (1) to (6) above as a raw material.
(8) In the biodegradable film as described in (7) above, a resin layer obtained by blending the component (A) and the component (B) is laminated on one side or both sides of the film, The biodegradable film characterized by not containing the component (C) in the resin layer.
(9) The biodegradable resin composition according to any one of (1) to (6) described above is used as a raw material and is manufactured by any one of thermoforming, press molding, and injection molding A biodegradable molded article characterized by

  The biodegradable resin composition of the present invention has little odor during processing, and the biodegradable film and biodegradable molded product produced using the composition have excellent physical properties and are biodegradable. Less elution of components.

  The biodegradable resin composition of the present invention (hereinafter also simply referred to as “the present composition”) comprises (A) a thermoplastic synthetic resin, (B) an inorganic filler, and (C) a biodegradable organic substance. It is made. Details will be described below.

(A) component:
The component (A) in the present invention is a thermoplastic synthetic resin. Examples of thermoplastic synthetic resins include polyolefin resins, copolymers of olefins and vinyl monomers, modified olefin copolymers, condensation polymer compounds, and polymers obtained by addition polymerization reactions. Can do. Examples of the polyolefin resin include homopolymers and copolymers such as polyethylene, polypropylene, polystyrene, polybutene, ethylene-α olefin copolymer, block polypropylene, and high pressure low density polyethylene.
Examples of the copolymer of olefin and vinyl monomer include ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ionomer (ethylene / carboxyl). Examples thereof include a metal ion-substituted product of an acid-containing vinyl monomer copolymer (for example, a sodium ion neutralized product of an ethylene / acrylic acid copolymer), an ethylene / vinyl alcohol copolymer, and the like.

Examples of the modified olefin copolymer include maleic anhydride-modified polypropylene and maleic anhydride-modified polyethylene.
Condensed polymer compounds include polycarbonate, polyacetal, polyamides such as nylon 6, nylon 6, 6, etc., polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, polyethersulfone, polyphenylene sulfide, polyimide, and phenol resin Etc.
Polymers obtained from addition polymerization reactions (polymers obtained from polar vinyl monomers and diene monomers) include polymethyl methacrylate, polystyrene, polyacrylonitrile, polyvinyl chloride, polybutadiene, polyisoprene, polyvinyl alcohol and other single weights. Examples thereof include a polymer, acrylonitrile / butadiene / styrene copolymer, SEBS which is a hydrogenated polymer, acrylonitrile / styrene copolymer, and high impact polystyrene (rubber-modified). Other examples include petroleum resins and thermoplastic elastomers.
Each of the above-mentioned thermoplastic synthetic resins may be used alone or in combination of two or more. Among the above-mentioned resins, polyolefin resins are particularly preferable in terms of moldability and physical properties.

(B) component:
The component (B) in the present invention is an inorganic filler. Inorganic fillers include talc, calcium carbonate, clay, precipitated barium sulfate, silica, kaolin, diatomaceous earth, calcium silicate, mica, alumina, aluminum sulfate, calcium sulfate, magnesium carbonate, carbon fiber, glass fiber, glass sphere, Preferred examples include graphite and zeolite. These may use 1 type and may use 2 or more types together.
Among these, talc is preferable in terms of rigidity and cost.

(C) component:
(C) component in this invention is a biodegradable organic substance. Examples of biodegradable organic substances include starch, cellulose, polylactic acid, and casein. Among these, starch is preferable from the viewpoint of biodegradability. Examples of the starch include those obtained from potato, wheat, corn, sweet potato, rice, cassava, kudzu, katakuri, mung bean, sago palm, bracken and the like.
By blending such a component (C), not only can the composition have biodegradability, but also the specific gravity can be lowered and the secondary workability can be improved.

The biodegradable resin composition of the present invention is obtained by blending the components (A) to (C) described above. The blending amount of the component (A) is 49 based on the total amount of the composition. Must be less than mass%. When this compounding quantity exceeds 49 mass%, biodegradability will fall.
(A) The preferable compounding quantity of a component is 40 mass% or less, More preferably, it is 20 mass% or less. On the other hand, when there are too few compounding quantities of (A) component, there exists a possibility that the moldability of a resin composition may deteriorate and the physical property of the manufactured film and molded article may fall. Therefore, the blending amount of the component (A) is preferably 30% by mass or more, and more preferably 35% by mass or more.

The blending ratio ((B) / (C)) of the component (B) and the component (C) in this composition is in the range of 3/7 to 7/3, preferably 5/5 to 6 in mass ratio. Up to / 4. By changing the blending ratio, the required characteristics required for a film or molded product can be easily adjusted. Specifically, if the blending ratio ((B) / (C)) is less than 3/7, the odor may be increased during processing. Further, when the molded product is a container or the like, the rigidity becomes inferior.
On the other hand, when the blending ratio ((B) / (C)) exceeds 7/3, physical properties (such as impact resistance) become inferior and biodegradation occurs when a molded article such as a container is produced. May decrease. The most preferable ratio is when (B) / (C) is 1/1.

In addition, the blending amount of the component (B) is preferably 20% by mass or more based on the total amount of the composition from the viewpoint of rigidity when formed into a molded product and the dispersibility of the component (C), and is 25% by mass or more. More preferably. However, it is preferably 40% by mass or less from the viewpoint of impact resistance,
More preferably, it is 30 mass% or less.
The blending ratio ((A) / (B)) of the component (A) and the component (B) in this composition is preferably in the range of 8/2 to 5/5 in terms of physical ratio, More preferably, it is from 7/3 to 6/4.

The blending amount of the component (C) is preferably 5% by mass or more and more preferably 15% by mass or more based on the total amount of the composition from the viewpoint of biodegradability and secondary processability. However, it is preferably 20% by mass or less and more preferably 25% by mass or less from the viewpoint of odor during extrusion and elution when a product (film or molded product) is used.
The blending ratio ((A) / (C)) of the component (A) and the component (C) in this composition is preferably in the range of 8/2 to 5/5 in terms of mass ratio from the viewpoint of workability. Is from 7/3 to 6/4.

(D) component:
A binder component can be mix | blended with this composition as (D) component as needed. A binder component is a component which exhibits the effect which improves the dispersibility of each component from (A) to (C) mentioned above more.
Examples of such component (D) include liquid paraffin, metal soap, silicone, side chain crystalline polyolefin, stearic acid, and polyglutamic acid. Here, the side chain crystalline polyolefin means a branched polyolefin described in, for example, JP-A No. 11-199641.
When such a component (D) is blended, for example, when the composition is extruded, the composition does not accumulate in the extruder, so that mass production performance is improved.
(D) The preferable compounding quantity of a component is about 1 mass% or more and 5 mass% or less on the composition whole quantity basis.
Moreover, you may mix | blend antioxidant, a lubricant, a nucleating agent, an ultraviolet absorber etc. as an additive other than (D) component.

This composition can be formed into a thin film by ordinary extrusion molding and can be provided as a biodegradable film. As extrusion molding, an inflation method, a T-die method, or the like can be preferably applied. This biodegradable film may be a single layer film, but from the viewpoint of preventing elution of the biodegradable organic substance (C) component, a resin layer ((C) component is not blended on one or both sides of the film (( It is preferable to laminate a layer formed by blending the component A) and the component (B). The thickness when the resin layer is laminated on one side of the film preferably has a thickness in the range of 5 to 10 with respect to the thickness 100 of the film itself. Even when the resin layers are laminated on both surfaces of the film, each of the resin layers preferably has the above-described thickness range. Even such a laminated film can be provided as a biodegradable film of the present invention as a whole.
The method for laminating the resin layer to the film may be an extrusion lamination method or a coextrusion method. Moreover, what is necessary is just to prepare the raw material of the resin layer which does not contain this (C) component only from the present composition which does not contain (C) component.

In addition, the biodegradable resin film of the present invention includes a film having a very thin thickness to a sheet having a thickness, that is, a biodegradable “resin sheet”.
When a bag is formed from a biodegradable resin film by heat sealing, the thickness is preferably 90 μm or less, more preferably 20 μm or more and 80 μm or less, and still more preferably 30 μm or more and 60 μm or less because rigidity needs to be suppressed.

  On the other hand, the present composition can be formed into a biodegradable molded body such as a container by a conventional molding method such as thermoforming, press molding, and injection molding after once molding a resin sheet having a predetermined thickness. As a resin sheet for forming such a molded body such as a container, the thickness is preferably 100 μm or more, more preferably 200 μm or more, and further preferably 300 μm or more, from the need to maintain rigidity. . However, since a container etc. are manufactured, it is preferable that it is 1400 micrometers or less from a viewpoint of a moldability, It is more preferable that it is 1200 micrometers or less, It is further more preferable that it is 1000 micrometers or less.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
[Example 1]
A biodegradable resin composition was prepared with the following composition, a resin sheet was produced from the composition, and a container was further produced from the resin sheet. For comparison, the following (C) component was not blended (the relative blending ratios of the other components were exactly the same), a resin composition was similarly prepared, and a resin sheet and a container were produced.
-Polypropylene resin (component (A)): 43.9% by mass
(Prime Polymer's Prime Polypro F-724NP (Random PP))
-Talc (component (B)): 27% by mass
Constarch (component (C)): 27% by mass
Magnesium stearate (component (D)): 1% by mass
-Liquid paraffin wax (component (D)): 1% by mass
-Antioxidant: 0.1% by mass
(Product name: Irgafos 168, manufactured by Ciba Geigy Japan)

  Specifically, the above-mentioned components were mixed and heated with a high-speed rotary mixer, and pellets with a processing temperature of 180 ° C. were produced with a twin-screw granulator. Next, the extrusion temperature of the obtained pellets was set to 175 ° C. with a 40Φ extruder having an L / D of 28 to obtain a resin sheet having a thickness of 0.8 mm and a width of 330 mm. The obtained resin sheet was vacuum-molded with a mold having a diameter of 80Φ and a depth of 60 mm to obtain a container. During the production of pellets and resin sheets, no odor based on the component (C) (biodegradable component) was felt at all for the obtained container. This container was evaluated for physical properties, odor, biodegradability and elution of biodegradable components by the following methods.

(1) Evaluation Method of Physical Properties 150 mL of water was put in the above container and boiled for 3 minutes in a microwave oven. Then, the presence or absence of deformation of the container and whether the container did not melt were visually confirmed.
Moreover, when producing the above-mentioned container, it was visually confirmed whether or not the container was cracked in the process of separating unnecessary parts after vacuum forming (trimming process). If the impact resistance of the container is low, cracking is likely to occur.
(2) Odor Evaluation Method After 150 mL of 95 ° C. hot water was placed in the above-mentioned container, it was naturally cooled by being covered with a glass plate. When the temperature of the hot water decreased to room temperature (25 ° C.), a tasting was performed (based on biodegradable components) to confirm the presence or absence of odor.
(3) Evaluation method of biodegradability The biodegradation rate was measured based on the modified MITI test method (OECD301C).
(4) Method for evaluating biodegradable component dissolution As with the physical properties, water is poured into a container and boiled in a microwave for 3 minutes, then the hot water is discarded, and the degree of swelling and smoothness of the inner surface of the container (slimming) The presence or absence of elution of the biodegradable component (biodegradable organic substance) was judged by visually or manually checking.

〔Evaluation results〕
(1) Physical properties Like the comparative container, there was no deformation or melting. Further, as in the comparative container, no cracks occurred in the above trimming process. Therefore, it can be said that the container of the present example has no inferiority in heat resistance and impact resistance as compared with the comparative container.
(2) Odor As with the comparative container, no odor was felt.
(3) Biodegradability 27% (decomposition rate) was a good value. No biodegradability was observed in the comparative container.
(4) Dissolvability of biodegradable components No dissolution of biodegradable components was observed.

[Example 2]
(A) After preparing a resin composition similarly to Example 1 and manufacturing a resin sheet and a container except having used polyethylene resin (Ube Industries R-300) instead of polypropylene resin as a component, it is the same Was evaluated. The same applies to the resin composition for comparison. During the production of pellets and resin sheets, no odor based on the component (C) (biodegradable component) was felt at all for the obtained container.

〔Evaluation results〕
(1) Physical properties Like the comparative container, there was no deformation or melting. Further, as in the comparative container, no cracks occurred in the above trimming process. Therefore, it can be said that the container of the present example has no inferiority in heat resistance and impact resistance as compared with the comparative container.
(2) Odor As with the comparative container, no odor was felt.
(3) Biodegradability 27% (decomposition rate) was a good value. No biodegradability was observed in the comparative container.
(4) Dissolvability of biodegradable components No dissolution of biodegradable components was observed.

Example 3
Pellets were manufactured using the resin composition of Example 1, and a film having a thickness of 50 μm was manufactured by an inflation molding method. Moreover, the film was similarly manufactured about the composition for a comparison which does not mix | blend (C) component. During the production of the pellets and films, the odor based on the component (C) (biodegradable component) was not recognized at all in the obtained film.
The physical properties (impact resistance, tensile properties) of the obtained film were measured based on JIS K 7124 and JIS K 7127. The biodegradability was evaluated in the same manner as in Example 1. Regarding elution of the biodegradable component, prepare a film bag, seal with 95 ° C. hot water, leave it for one day, evaluate the inner surface in contact with the hot water in the same manner as in Example 1, and check whether the biodegradable component is eluted. I confirmed.

〔Evaluation results〕
The obtained film was comparable in impact resistance and tensile properties (strength, elongation, etc.) to the film produced for comparison. Therefore, it can be understood that it can be used as a general shopping bag.
Further, biodegradability was as good as 27% (decomposition rate), and no biodegradable components were eluted. The film produced for comparison was not biodegradable at all.

[Comparative Example 1]
A resin composition was prepared in the same manner as in Example 1 with the following composition, and a resin sheet and a container were produced, and the same evaluation was performed.
-Polypropylene resin (component (A)): 43.9% by mass
-Talc (component (B)): 54% by mass
Magnesium stearate (component (D)): 1% by mass
-Liquid paraffin wax (component (D)): 1% by mass
-Antioxidant: 0.1% by mass
(Product name: Irgafos 168, manufactured by Ciba Geigy Japan)
〔Evaluation results〕
The obtained container had low impact strength, and cracking occurred in the trimming process.

[Comparative Example 2]
A resin composition was prepared in the same manner as in Example 1 with the following composition (no component (B)) to produce a resin sheet.
-Polypropylene resin (component (A)): 30% by mass
Constarch (component (C)): 54% by mass
Magnesium stearate (component (D)): 1% by mass
-Liquid paraffin wax (component (D)): 1% by mass
-Antioxidant: 0.1% by mass
(Product name: Irgafos 168, manufactured by Ciba Geigy Japan)
〔Evaluation results〕
When producing a resin sheet from pellets having the above composition, the odor of starch was so severe that the subsequent container production was abandoned. In addition, a large amount of starch burnt was deposited on the lip mouth of the die, making it difficult to form a sheet. Therefore, the container could not be evaluated.

Claims (9)

(A) a thermoplastic synthetic resin, (B) an inorganic filler, and (C) a biodegradable organic substance,
The blending amount of the component (A) is 49% by mass or less based on the total amount of the composition,
The biodegradable resin composition characterized in that the blending ratio ((B) / (C)) of the component (B) and the component (C) is in the range of 3/7 to 7/3 by mass ratio. . In the biodegradable resin composition according to claim 1,
The biodegradable resin composition, wherein the component (A) is a polyolefin resin. In the biodegradable resin composition according to claim 1 or 2,
The component (B) is talc, calcium carbonate, clay, precipitated barium sulfate, silica, kaolin, diatomaceous earth, calcium silicate, mica, alumina, aluminum sulfate, calcium sulfate, magnesium carbonate, carbon fiber, glass fiber, glass sphere A biodegradable resin composition characterized by being at least one selected from graphite and zeolite. In the biodegradable resin composition according to any one of claims 1 to 3,
The biodegradable resin composition, wherein the component (C) is at least one selected from starch, cellulose, polylactic acid, and casein. In the biodegradable resin composition according to any one of claims 1 to 4,
And (D) a biodegradable resin composition comprising a binder component. In the biodegradable resin composition according to claim 5,
The component (D) is at least one selected from liquid paraffin, metal soap, silicone, side chain crystalline polyolefin, stearic acid, and polyglutamic acid. A biodegradable film produced using the biodegradable resin composition according to any one of claims 1 to 6 as a raw material. The biodegradable film according to claim 7,
On one side or both sides of the film, a resin layer formed by blending the component (A) and the component (B) is laminated,
The biodegradable film, wherein the resin layer does not contain the component (C). A biodegradable resin composition according to any one of claims 1 to 6, wherein the biodegradable resin composition as a raw material is produced by any one of thermoforming, press molding, and injection molding. Degradable molded product.