JP2006077126A - Resin composition and resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molded product excellent in impact resistance and given by using a lactic acid-based resin as a base. <P>SOLUTION: This resin composition is formed by mixing 1-20 pts.mass of vegetable fat and oil and 0.01-5 pts.mass of a crosslinking agent which crosslinks at least the vegetable fat and oil into 100 pts.mass of a lactic acid-based resin. Caster oil is preferably used as the vegetable fat and oil. The resin composition is molded into the molded product having an Izod impact strength of ≥5 kJ/m<SP>2</SP>, so that the resin molded product is excellent in the impact strength. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin molded body having a plant raw material resin as a base component, viscoelasticity like rubber, and excellent impact resistance.

Plastics have permeated all industrial and daily necessities, with annual global production reaching approximately 100 million tons. Most of them are discarded after use, and this has been recognized as one of the causes that disturb the global environment. For this reason, effective use of exhaustible resources has been emphasized in recent years, and the use of renewable resources has become an important issue.
Currently, the most noticeable solution is the use of plant-based plastics. Plant-based plastics can not only use non-depleted resources, save exhaustible resources during plastic production, but also have excellent recyclability.

Among plant-derived plastics, in particular, lactic acid-based resins are made from lactic acid obtained by fermentation of starch, can be mass-produced by chemical engineering, and have excellent transparency, rigidity, heat resistance, etc. As an alternative material for polyethylene terephthalate and polyethylene terephthalate, it is attracting attention in the field of film packaging and injection molding.
However, although the lactic acid-based resin has high rigidity, it is a material that is relatively weak in impact resistance and is brittle, and it is very difficult to use it in a field that requires impact resistance alone. In view of this, Japanese Patent Application Laid-Open No. 11-116785 (Patent Document 1) and the like have proposed a method for improving impact resistance by adding animal and vegetable oils to a polylactic acid resin.

In Patent Document 1, epoxidized soybean oil is listed as an animal and vegetable oil to be blended with a polylactic acid resin. However, by simply blending with an animal and vegetable oil to be blended with a polylactic acid resin, the softening of the polylactic acid resin is described. It is difficult to obtain a sufficient impact resistance improvement effect because the required elasticity, particularly at a high temperature, cannot be imparted.
Japanese Patent Laid-Open No. 11-116785

  This invention is made | formed in view of the said problem, and not only mix | blends vegetable oil and fat with respect to lactic acid-type resin, but also mix | blends vegetable oil and fat by blending the crosslinking agent which bridge | crosslinks vegetable oil and fat at least. Thus, it is an object to improve the impact resistance by imparting viscoelasticity like rubber.

  In order to solve the above-mentioned problems, first, the present invention is based on 100 parts by mass of the lactic acid resin (A), 1 to 20 parts by mass of vegetable oil (B), and a crosslinking agent that crosslinks at least the vegetable oil ( C) The resin composition formed by blending 0.01 to 5 parts by mass is provided.

  If a vegetable oil and fat is simply blended with a lactic acid resin and the crosslinking agent does not coexist, the vegetable oil and fat will function as a plasticizer, and the molded product of the resin composition becomes soft and has a glass transition temperature (Tg). descend. On the other hand, when vegetable oils and fats and a crosslinking agent are blended with lactic acid-based resins, vegetable oils and fats and vegetable oils and lactic acid-based resins can be cross-linked, and the vegetable oils and fats have a high molecular weight and have viscoelastic properties like rubber. The impact resistance of a molded article made of a product can be improved. And the molded object of this resin composition does not soften, and the fall of Tg hardly arises.

In this invention, although various vegetable fats and oils can be used, it is preferable to use a castor oil as vegetable fats and oils (B) especially. Castor oil has a refractive index close to that of a lactic acid resin, in addition to being excellent in stability, dispersibility, low temperature characteristics, electrical characteristics, and color. Therefore, impact resistance can be imparted to the molded body of the lactic acid-based resin with almost no loss of transparency.
In addition, transparency can be maintained as the refractive index of the vegetable oil (B) is close to the refractive index of the lactic acid-based resin and is in the range of ± 5% with respect to the refractive index of the lactic acid-based resin. Therefore, when providing the resin molding which needs transparency, the said vegetable oil and fat is not limited to a castor oil, The cross-linking agent which bridge | crosslinks the vegetable oil and fat (B) which has the refractive index of the said range, and this vegetable oil and fat mutually. You may mix | blend.

  In the present invention, various compounds can be used as the crosslinking agent (C). Preferred examples of the crosslinking agent include isocyanate compounds and carbodiimide compounds.

Since isocyanate compounds are excellent in reactivity, vegetable oils and fats can be efficiently crosslinked with a small amount of addition. In addition, the isocyanate compound efficiently promotes crosslinking between the lactic acid resin and the vegetable oil.
The carbodiimide compound is not only excellent in reactivity, but also can impart hydrolysis resistance to the lactic acid resin. Thereby, the lactic acid-based resin to which the vegetable oil and fat and the carbodiimide compound are added can be used for applications that require high durability.

Secondly, the present invention provides a resin molded body comprising a resin composition, and the resin molded body has viscoelasticity by blending a vegetable oil and a crosslinking agent that crosslinks the vegetable oil and fat. because you are, the Izod impact strength is measured according to JISK-7110 5kJ / ^{m 2} or more, more preferably be those as 8 kJ / ^{m 2} or more, excellent in impact resistance.
Moreover, since the resin composition of the present invention has heat resistance, it can be injection-molded, and an injection-molded body having a required shape can be produced.
Although the form of a molded object is not specifically limited, For example, the plate etc. which have a film, a sheet | seat, a planar or three-dimensional shape, etc. are contained. Since it has excellent impact resistance, it can be used in applications requiring heat resistance in all fields such as home appliances, automobile interior parts, and building materials.

The present invention provides a film, sheet, or plate in which the resin composition of the present invention is formed not only by the injection molding but also by extrusion molding or the like. Films, sheets or plates having an average thickness of about 50 to 1000 μm also have excellent heat resistance, so that they can be used for applications that require impact resistance such as insulating members for OA equipment.
The film is defined in JIS K 6900 as “a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. It is said that. The sheet is said to be "a thin product, generally a product whose thickness is small and flat for the length and width". Thus, since the distinction between a film and a sheet is not clear, in the present invention, the film is distinguished as having a thickness of less than 200 μm, and the sheet is distinguished as having a thickness of from 200 μm to less than 500 μm. A three-dimensional thing is called a plate.

As described above, vegetable oils and fats are cross-linked by blending vegetable oils and fats and a crosslinking agent with the lactic acid resins, and further, vegetable oils and fats and lactic acid-based resins are cross-linked. Vegetable oils and fats act as rubber components by increasing their molecular weight by crosslinking. As a result, the resin composition of the present invention has the required viscoelasticity without being softened, and can provide a molded article excellent in impact resistance.
In addition, since the resin composition of the present invention contains a lactic acid resin, it is provided with recyclability and does not adversely affect the natural environment even when discarded after use.

Hereinafter, embodiments of the present invention will be described.
The resin composition of the present invention contains a lactic acid resin (A), a vegetable oil (B), and a crosslinking agent (C). ) Is 1 to 20 parts by mass, and the crosslinking agent (C) is 0.01 to 5 parts by mass.
The components (A), (B), and (C) will be described in detail below.

(Lactic acid resin)
The lactic acid-based resin (A) used in the present invention includes poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, structural units that are L-lactic acid and D -Copolymer poly (DL-lactic acid) which is lactic acid or a mixture thereof.

  The DL configuration of the lactic acid resin (molar ratio of D-lactic acid structure to L-lactic acid structure) is L-lactic acid: D-lactic acid = 100: 0 to 90:10, or L-lactic acid: D-lactic acid = 0. : It is preferable that it is 100-10: 90. Outside this range, the crystallinity of the lactic acid-based resin is low, and the molded part is difficult to obtain heat resistance, and its use may be limited. More preferably, L-lactic acid: D-lactic acid = 99.5: 0.5 to 94: 6, or L-lactic acid: D-lactic acid = 0.5: 99.5 to 6:94.

  A plurality of lactic acid resins having different DL configurations can also be mixed and used. In that case, it is preferable that a plurality of lactic acid-based resins each have a DL structure in the above range, or the average of the whole has a DL structure in the above range. For example, when L-lactic acid or a homopolymer of D-lactic acid and a copolymer of L-lactic acid and D-lactic acid are mixed, bleeding is unlikely to occur and the balance of heat resistance can be controlled.

Representative examples of the lactic acid resin suitably used in the present invention include “Lacia (trade name)” series manufactured by Mitsui Chemicals, Inc. and “Nature” manufactured by Cargill Dow.
"Works (trade name)" series and the like.

  Any known method such as a condensation polymerization method or a ring-opening polymerization method can be employed as the polymerization method for the lactic acid resin. For example, in the condensation polymerization method, L-lactic acid, D-lactic acid, or a mixture thereof can be directly subjected to dehydration condensation polymerization to obtain a lactic acid resin having an arbitrary composition.

  A lactate resin can be obtained by subjecting lactide, which is a cyclic dimer of lactic acid, to ring-opening polymerization using a selected catalyst while using a polymerization regulator or the like as necessary. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide composed of L-lactic acid and D-lactic acid. In the ring-opening polymerization method, a lactic acid resin having an arbitrary composition and crystallinity can be obtained by mixing and polymerizing as necessary.

Furthermore, if necessary, such as improving heat resistance, a small amount of a copolymer component may be used as long as the essential properties of the lactic acid resin are not impaired, that is, within a range containing 90 wt% or more of the lactic acid resin component. Good.
Examples of such copolymer components include non-aliphatic dicarboxylic acids such as terephthalic acid, non-aliphatic diols such as bisphenol A ethylene oxide adducts, and the like. Further, other hydroxycarboxylic acid (preferably α-hydroxycarboxylic acid) other than lactic acid, aliphatic diol, aliphatic dicarboxylic acid and the like may be used as a copolymerization component. These copolymerization components may be used alone or in combination of two or more.

  Examples of other hydroxycarboxylic acid used as a copolymer component of the lactic acid-based resin include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone.

Examples of the aliphatic diol used as a copolymer component of the lactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like.
Examples of the aliphatic dicarboxylic acid used as a copolymerization component of the lactic acid-based resin include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  Furthermore, a small amount of chain extender may be used for the purpose of increasing the molecular weight of the lactic acid resin. As the chain extender, for example, a diisocyanate compound, an epoxy compound, an acid anhydride and the like can be used.

  The preferable range of the weight average molecular weight of the lactic acid resin is 50,000 to 400,000, more preferably 100,000 to 250,000. When the weight average molecular weight is less than 50,000, practical physical properties of the lactic acid resin are hardly expressed. When the weight average molecular weight exceeds 400,000, the melt viscosity of the lactic acid resin becomes too high, and the molding processability is lowered.

(vegetable oil)
The vegetable oils and fats (B) used in the present invention include drying oils, semi-drying oils, non-drying oils and other vegetable fats. In addition, the following vegetable fats and oils may be used independently and may be used in combination of multiple.

  Specific examples of drying oils include: Acamrit oil, hemp seed oil, linseed oil, isano oil, sea urchin kernel oil, sesame oil, pear oil, pod oil, walnut oil, poppy oil, pomegranate seed oil, safflower oil, shiflower oil Nagiri oil, soybean oil, tobacco seed oil, tomato seed kernel oil, Japanese drill oil, rubber seed oil, evening primrose seed oil, sunflower seed oil, grape seed oil, spinach seed oil, honey seed oil, rumba nut oil and the like.

  Specific examples of semi-drying oil include apricot kernel oil, orange seed oil, pumpkin seed oil, mustard rape seed oil, sesame oil, wheat germ oil, western potato oil, radish seed oil, corn oil, tomato seed oil, rapeseed oil, Examples include carrot seed oil, bran oil, pecan oil, tonsil oil, cottonseed oil, rye oil, lemon oil and the like.

  Specific examples of non-drying oils include Asaga oil, Japanese arabic oil, olive oil, olive kernel oil, cashew seed oil, kapok oil, cabbage seed oil, coffee bean oil, sazanka oil, tea oil, camellia oil, Dongguan oil, ergot oil , Castor oil, peanut oil and the like.

  Specific examples of other plant fats include iribe fat, ukufuba fat, roux wax, cacao butter, garcinia fat, cous cinnamon fat, cousin oleum, laurel coconut oil, kofun kernel oil, shea butter, daikon oil, tsukan oil, Tucan kernel oil, spruce oil, garlic oil, babas kernel oil, palm oil, palm kernel oil, hydnocalps oil, Brazil palm kernel oil, borneo fat, murmuru fat, tree wax, palm oil and the like.

  Among these, castor oil is most suitable in the present invention. Castor oil is excellent in stability, dispersibility, low temperature characteristics, electrical characteristics, and color. Moreover, since the refractive index of castor oil is close to the refractive index of lactic acid resin, the impact resistance can be improved by adding castor oil with almost no loss of transparency of the lactic acid resin.

  Polylactic acid has a refractive index of 1.455, and castor oil has a refractive index of 1.477. Therefore, in addition to castor oil, when using vegetable oils and fats whose refractive index is about ± 5% of the refractive index of the lactic acid-based resin to which the dividend is distributed, lactic acid can be used with almost no loss of transparency to the same extent as when castor oil is used. The effect of imparting impact resistance to the resin can be expected.

  Moreover, the said vegetable oil and fat can also be used as a vegetable oil and fat derivative which performed processes, such as hydrogenation, saponification decomposition, oxidation polymerization, and self-condensation.

  About the compounding quantity of vegetable oil and fat, vegetable oil and fat shall be 1-20 mass parts with respect to 100 mass parts of lactic acid-type resin, Preferably it is 5-15 mass parts. By blending vegetable oils and fats in such a range, the impact resistance of the lactic acid-based resin can be improved without causing the vegetable oils and fats to bleed out. If the amount of vegetable oil / fat is less than 1 part by mass per 100 parts by mass of the lactic acid-based resin, the effect of improving the impact resistance of the lactic acid-based resin can hardly be obtained. It becomes difficult to prevent.

(Crosslinking agent)
In this invention, although various compounds can be used as a crosslinking agent (C), what can bridge | crosslink lactic acid-type resin and vegetable fats and oils while being able to bridge | crosslink vegetable oils and fats suitably is used suitably. For example, an isocyanate compound, a carbodiimide compound, an epoxy compound containing an epoxy group, a metal compound, an aziridinyl compound, and the like can be given. The crosslinking agent not only contributes to increase the molecular weight of the vegetable oil and fat, but also achieves suitable viscoelasticity and prevents bleeding out of the vegetable oil and fat. It is desirable that it also contributes to cross-linking.

Among these, it is particularly preferable to use an isocyanate compound or a carbodiimide compound. The isocyanate compound not only efficiently cross-links vegetable oils and fats with a small amount of addition, but also efficiently crosslinks lactic acid resins and vegetable oils and fats.
Moreover, the carbodiimide compound can provide not only efficient crosslinking but also hydrolysis resistance to the lactic acid-based resin. Although the specific example of an isocyanate compound and a carbodiimide compound is given to the following, it is not limited to this.

  Specific examples of the isocyanate compound include 4,4′-diphenylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, isophorone diisocyanate, and methylenebiscyclohexyl diisocyanate.

  Specific examples of the carbodiimide compound include bis (dipropylphenyl) carbodiimide, poly (4,4′-diphenylmethanecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (Diisopropylphenylenecarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide), poly (triisopropylphenylenecarbodiimide) and the like.

The compounding amount of the crosslinking agent is 0.01 to 5 parts by mass, preferably 0.05 to 4 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the lactic acid resin. .
By blending a crosslinking agent in the range of 0.01 to 5 parts by mass, it is possible to perform crosslinking of vegetable oils and fats and crosslinking of lactic acid resins and vegetable oils without causing gelation of lactic acid resins. . When the blending amount of the crosslinking agent is less than 0.01 parts by mass per 100 parts by mass of the lactic acid resin, the vegetable oil cannot be sufficiently crosslinked, and the effect of improving the impact resistance of the resin molded product cannot be obtained. On the other hand, when the amount of the crosslinking agent exceeds 5 parts by mass per 100 parts by mass of the lactic acid resin, the viscosity increases and the moldability is inferior.

  The resin composition of the present invention includes a heat stabilizer, an antioxidant, a UV absorber, a light stabilizer, a pigment, a dye, a nucleating agent, a plasticizer, an inorganic filler, and the like as long as the effects of the present invention are not impaired. Additives can be blended. The amount of these additives is appropriately selected according to the desired performance.

  The resin composition of the present invention can be used after being processed into a film, sheet, plate or the like by various molding methods. The film or sheet is a flat material, but the plate includes a flat material and a three-dimensional structure material having a three-dimensional structure. Hereinafter, an example of the molding method will be described.

  First, a lactic acid resin (A), a vegetable oil (B), a crosslinking agent (C), and other additives to be blended as necessary are mixed. In the case of performing extrusion molding or injection molding, mixing is performed by charging all raw materials into a raw material charging port attached to the extrusion molding machine or the injection molding machine. The raw materials are kneaded in a molding machine or mixed immediately before the extrusion port, and then directly extruded into an injection mold or an extrusion mold, and molded into a predetermined shape with the mold. Alternatively, a dry blended raw material is extruded into a strand shape using a twin screw extruder to create a pellet, and the pellet is extruded into a mold such as an injection mold or an extrusion mold to obtain a predetermined shape. Mold. In any method, it is necessary to consider a decrease in molecular weight due to decomposition of the raw material, but the latter is preferably selected for uniform mixing.

  Specifically, the lactic acid resin (A), vegetable oil (B), cross-linking agent (C) and other additives are sufficiently dried to remove moisture, and then melt mixed using a twin screw extruder. Extrude into a strand shape to make pellets. In that case, considering that the melting point of the lactic acid resin changes depending on the molar ratio of the L-lactic acid structure and the D-lactic acid structure (DL configuration), the viscosity of the resin composition changes depending on the blending ratio of the raw materials, etc. It is preferable to appropriately select the melt extrusion temperature. In practice, a temperature range of 160-230 ° C. is usually selected.

  The pellets prepared by the above method are sufficiently dried to remove moisture, and then injection molding or extrusion molding is performed by the following method to form a sheet or plate. Furthermore, a film is shape | molded by extending | stretching a sheet | seat. A three-dimensional structure material with a three-dimensional structure is created directly by injection molding, or a sheet or flat plate extruded by a predetermined thickness is formed into a required three-dimensional shape by pressing or T-die casting. To do.

  The injection molding method is not particularly limited, but typically, an injection molding method such as a general injection molding method for a thermoplastic resin, a gas assist molding method, an injection compression molding method or the like is used. In addition to the above methods, in-mold molding method, gas press molding method, two-color molding method, sandwich molding method, PUSH-PULL, SCORIM (Shear Controlled Orientation in Injection Molding), etc. may be adopted according to the purpose. it can.

  The film is formed by stretching a sheet obtained by extrusion molding in at least one direction by a film stretching method. Any method may be employed as long as it is a film stretching method. For example, a roll stretching method, a tenter stretching method, a tubular method, an inflation method, or the like can be employed.

Molding of the resin composition of the present invention is excellent in impact resistance, as Izod impact strength is measured according to JISK-7110, 5kJ / ^{m 2} or more, further to achieve 8 kJ / ^{m 2} or more It is possible. Such high impact resistance is at a level that cannot be achieved by a conventional resin molded body based on a lactic acid resin.

Hereinafter, the present invention will be described based on examples and comparative examples.
The components and blending amounts of the resin compositions of each Example and each Comparative Example are shown in Tables 1 and 2 below. In Tables 1 and 2, the unit of the numerical value indicating the component amount is part by mass.

In each example and each comparative example, impact resistance was evaluated by the following method.
(Impact resistance)
A No. 2A test piece (notched, length 64 mm x width 12.7 mm x thickness 4 mm) was prepared according to JISK-7110, and an Izod impact tester (model: JISL-D) manufactured by Toyo Seiki Seisakusho Co., Ltd. ) Was used to measure the Izod impact strength at 23 ° C. An Izod impact strength of 5 kJ / m ² or more was accepted.

Each component described in Tables 1 and 2 is as follows.
Lactic acid resin A: “Nature” manufactured by Cargill Dow
Works 4032D (trade name) "
(DL constitution: L-lactic acid / D-lactic acid = 98.6 / 1.4, weight average molecular weight: 200,000)
Vegetable oil and fat B-1: Castor oil manufactured by Nacalai Tesque Co., Ltd. Vegetable oil and fat B-2: Amani oil "manufactured by Nakarai-Tex Corporation"
Vegetable oil B-3; cottonseed oil “Nakarai-Tex”
Crosslinking agent C: 4,4'-diphenylmethane diisocyanate manufactured by Nacalai Tesque
(MDI)

Example 1
Dry blend of 100 parts by weight of lactic acid resin A with 1 part by weight of vegetable oil B-1 and 0.2 parts by weight of cross-linking agent C, 40 mmφ small size same direction made by Mitsubishi Heavy Industries Ltd. It supplied to the twin-screw extruder, knead | mixed at 180 degreeC, it was set as the compound, and this was shape | molded in the pellet form. The obtained pellets were injection molded into a plate having a length of 200 mm, a width of 3 mm and a thickness of 4 mm using an injection molding machine “IS50E (trade name)” (screw diameter: 25 mm) manufactured by Toshiba Machine Co., Ltd. The main molding conditions are as follows.

1) Temperature conditions: cylinder temperature (195 ° C), mold temperature (20 ° C)
2) Injection conditions: injection pressure (115 MPa), holding pressure (55 MPa)
3) Measuring conditions: screw rotation speed (65 rpm), back pressure (15 MPa)

  Next, the plate material obtained by injection molding was allowed to stand in a baking test apparatus “DKS-5S (trade name)” manufactured by Daiei Kagaku Seisakusho Co., Ltd., and heat-treated at 70 ° C. for 2 hours. Thereafter, impact resistance was evaluated using the plate material after the heat treatment. The results are shown in Table 1.

(Example 2)
In the same manner as in Example 1, except that 100 parts by mass of the lactic acid-based resin A was dry blended with 20 parts by mass of vegetable oil B-1 and 0.2 parts by mass of the crosslinking agent C. Production and evaluation of a plate material which is an injection-molded body were performed. The results are shown in Table 1.

(Example 3)
In the same manner as in Example 1, except that 100 parts by mass of lactic acid-based resin A was dry blended with 10 parts by mass of vegetable oil B-1 and 0.01 parts by mass of crosslinking agent C. Production and evaluation of a plate material which is an injection-molded body were performed. The results are shown in Table 1.

Example 4
Injection molding in the same manner as in Example 1 except that 100 parts by mass of lactic acid resin A was dry blended with 10 parts by mass of vegetable oil B-1 and 5 parts by mass of crosslinking agent C. Production and evaluation of a plate material as a body were performed. The results are shown in Table 1.

(Example 5)
In the same manner as in Example 1, except that 100 parts by mass of lactic acid resin A was dry blended with 10 parts by mass of vegetable oil B-2 and 0.2 parts by mass of crosslinking agent C. Production and evaluation of a plate material which is an injection-molded body were performed. The results are shown in Table 1.

(Example 6)
In the same manner as in Example 1, except that 100 parts by mass of the lactic acid-based resin A was dry blended with 10 parts by mass of vegetable oil B-3 and 1.0 part by mass of the crosslinking agent C. Production and evaluation of a plate material which is an injection-molded body were performed. The results are shown in Table 1.

(Comparative Example 1)
Only the lactic acid-based resin was injection-molded into a plate material in the same manner as in Example 1, and the evaluation was performed in the same manner as in Example 1. That is, the resin composition of this comparative example does not contain vegetable oils or fats and crosslinking agents. The results are shown in Table 2 above.

(Comparative Example 2)
Production and evaluation of a plate material that is an injection-molded body in the same manner as in Example 1 except that 10 parts by mass of vegetable oil B-1 was blended with 100 parts by mass of lactic acid-based resin A. Went. That is, the resin composition of this comparative example does not contain a crosslinking agent. The results are shown in Table 2.

(Comparative Example 3)
Production and evaluation of a plate material that is an injection-molded body in the same manner as in Example 1 except that dry blending of 0.2 parts by mass of the crosslinking agent C is performed with respect to 100 parts by mass of the lactic acid resin A. Went. That is, the resin composition of this comparative example does not contain vegetable oils and fats. The results are shown in Table 2.

As is clear from Table 1, it can be confirmed that the injection molded articles of Examples 1 to 5 made of the resin composition of the present invention have an Izod impact strength of 5 kJ / m ² or more and are excellent in impact resistance. It was. Moreover, in the range of 1-20 mass parts of vegetable oils and fats with respect to 100 mass parts of lactic acid-type resin A, the tendency for impact resistance to improve was seen, so that there were many compounding quantities of vegetable oils and fats.

As is apparent from Table 2, the injection molded articles of Comparative Example 1 containing neither vegetable oil or fat and cross-linking agent, nor Comparative Examples 2 to 3 containing either one of vegetable oil or fat and cross-linking agent were Izod impact strength. Are less than 5 kJ / m ² , confirming that the impact resistance is poor. The injection-molded products of Comparative Examples 1 to 3 had a shock resistance that did not reach a practical level, and their applications were very limited.

FIG. 1 shows Example 5 (3, 3 ′ in the figure), Comparative Example 1 (1, 1 ′ in the figure) measured using the “VES-F3” viscoelasticity measuring device manufactured by Iwaki Seisakusho Co., Ltd. The graph of the viscoelasticity measurement result of the board | plate material of the comparative example 2 (2, 2 'in a figure) is shown.
From FIG. 1, it can be understood that in Comparative Example 2, the glass transition temperature is larger than that of Comparative Example 1 and is shifted to the lower temperature side. The decrease in the glass transition temperature is considered to be because the vegetable oil contained in the plate material of Comparative Example 2 acts as a plasticizer.
On the other hand, in Example 5, the glass transition temperature is hardly lowered as compared with Comparative Example 1. This is because the vegetable oil contained in Example 5 is cross-linked by the cross-linking agent and functions as a rubber component without functioning as a plasticizer. The fact that sub-dispersion by rubber is observed at around −60 ° C. in the graph of Example 5 also indicates that vegetable oils and fats are crosslinked by a crosslinking agent and have rubber elasticity.

  Since the resin composition of the present invention provides a molded article having excellent impact resistance, the present invention can be applied to various molded products, for example, a film, a sheet, a flat plate, or a three-dimensional plate. can do. The resin composition of the present invention and its molded product are used in various industrial applications such as home appliances, OA equipment, and automobile parts, and various packaging films such as food, medical, medicine, and cosmetics, agricultural films, industrial protective films, and daily life. Widely used as a product.

It is a graph of the viscoelasticity measurement result of the board | plate material of Example 2, the comparative example 1, and the comparative example 2. FIG.

Claims (7)

  1 to 20 parts by mass of vegetable oil (B) and 0.01 to 5 parts by mass of a crosslinking agent (C) for crosslinking at least the vegetable oil and fat are blended with 100 parts by mass of the lactic acid resin (A). Resin composition.   The resin composition according to claim 1, wherein the vegetable oil (B) is castor oil.   The resin composition according to claim 1, wherein the vegetable oil (B) has a refractive index close to that of the lactic acid resin and in a range of ± 5% with respect to the refractive index of the lactic acid resin.   The resin composition according to any one of claims 1 to 3, wherein the crosslinking agent (C) is an isocyanate compound or a carbodiimide compound. 5. A molded article of the resin composition according to claim 1, wherein the molded article has an Izod impact strength of 5 kJ / m ² or more measured according to JISK-7110.   The molded product according to claim 5, comprising a film having an average thickness of less than 200 µm, a sheet having an average thickness of 200 µm or more and less than 500 µm, a flat plate having an average thickness of 500 µm or more, or a three-dimensional plate.   The molded article according to claim 5 or 6, which has transparency.

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