JP3121510B2 - Method for producing biodegradable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a biodegradable resin composition. More specifically, the present invention relates to a method for producing a biodegradable resin composition by heating and kneading a thermoplastic resin together with an oil and an organic peroxide.

[0002]

BACKGROUND OF THE INVENTION Japanese Patent Application Laid-Open No. 49-55,740 and corresponding US Pat. No. 4,016,117 disclose biological materials containing starch granules dispersed in a thermoplastic resin or a thermosetting elastomer resin. A degradable resin composition is disclosed.

Japanese Patent Publication No. 52-42,187 discloses carbon, a synthetic resin based on carbon bonds, biodegradable particles such as natural starch granules, and a resin having at least one double bond in one molecule. Biodegradable compositions containing saturated fatty acids or derivatives thereof are disclosed.

Japanese Patent Publication No. 60-41,089 discloses starch particles which are made hydrophobic by reacting the surface of the starch particles with a compound which easily reacts with hydroxyl groups to form ethers or esters, and a synthetic resin. A biodegradable composition is disclosed.

Further, Japanese Patent Publication No. 56-44,907 discloses straight-chain higher alcohols, higher alcohols having straight-chain higher fatty acid methyl branches, higher fatty acids having methyl branches, esters thereof, and di-esters of straight-chain higher fatty acids. -And tri-glycerides, di- of higher fatty acids having methyl branches
And at least one organic substance and an inorganic substance selected from the group consisting of: and tri-glyceride, wherein the amount of the organic substance is 2% or more, and the total amount of the organic substance and the inorganic substance is 60%. A biodegradable polyolefin composition characterized by not exceeding is disclosed.

[0006] The publication discloses that when a JIS mold resistance test is performed after irradiating the above polyolefin composition with ultraviolet rays, a certain composition range, that is, myristyl myristate 2 to 2, is obtained.
The fact that the strength degradation is dramatically accelerated by a polyethylene composition containing 10% and calcium carbonate of 30 to 40%, and that the resin material is easily decomposed rapidly when the resin material is dumped outdoors. Is described.

Also, Professor Osawa of the Department of Materials Engineering, Faculty of Engineering, Gunma University prepared a composition comprising 10% corn starch in an ethylene / carbon monoxide copolymer and a composition comprising 70% paper in the copolymer. Then, these are exposed to ultraviolet light for 24 hours with a high-pressure mercury lamp or exposed outdoors, and then buried indoors and outdoors to measure the weight loss rate, which is almost twice that of the ethylene / carbon monoxide copolymer alone. (Nippon Kogyo Shimbun, March 1992)
March 9).

[0008] A method for promoting photodegradation of a polymer substance using ultraviolet light is disclosed in Japanese Patent Application Laid-Open No. 61-285,226, which is one of the inventors of the present invention. Is disclosed.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel biodegradable resin composition. Another object of the present invention is to provide a method for producing a novel biodegradable resin composition in which biodegradation proceeds advantageously by being buried in soil, garbage or compost.

It is a further object of the present invention to provide a novel biodegradable resin having ultraviolet decomposability, which is decomposed by irradiation with ultraviolet light, and then buried in soil, garbage or compost, whereby biodegradation proceeds more advantageously. It is to provide a method for producing a composition. Still other objects and advantages of the present invention will become apparent from the following description.

[0011]

According to the present invention, the above objects and advantages of the present invention include: (a) a thermoplastic resin;
Oil and / or oxidized oil , where oil and oxidized oil are
A biodegradable resin composition, which is an animal oil, a vegetable oil or an oxidized oil thereof, and (c) kneading an organic peroxide at a temperature not lower than the softening temperature of the thermoplastic resin (a). Achieved by manufacturing methods.

As the thermoplastic resin (a), a general thermoplastic resin is used without any particular limitation. For example, a polyolefin-based resin composed of a homopolymer or copolymer of α-olefin such as ethylene, propylene, 1-butene, 4-methyl-1-pentene or a copolymer of these α-olefin and another comonomer; Polystyrene resin; ABS resin; polyvinyl chloride resin; polyvinylidene chloride-vinyl copolymer resin; polycarbonate resin; polyester resin; polyamide resin; polyphenylene oxide resin; polyvinyl alcohol resin (ethylene-vinyl acetate resin). Polymer saponified product); polyurethane resin; polyether resin; rubbers such as natural rubber, isoprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, and mixtures thereof. . Among these, use of a polyolefin-based resin or a polystyrene-based resin is preferred.

The oil and the oxidized oil (b) include animal oils,
The need use those vegetable oils and let them be oxidized. In particular, those obtained by oxidizing vegetable oil by boiling or the like are preferable. The time for the boiling treatment is not particularly limited, but the treatment is preferably performed for 5 hours or more. Preferred vegetable oils include
Rapeseed oil, corn oil, sunflower oil, safflower oil and the like are exemplified. By using those obtained by oxidizing these vegetable oils, the oxidation start temperature of the resin composition is lowered, and the biodegradability is promoted. The blending amount of oil and / or oxidized oil is
It is preferably 0.1 to 10% by weight, more preferably 0.3 to 5% by weight, based on the thermoplastic resin. If the blending amount of oil and / or oxidized oil is 0.1% by weight or more,
The biodegradability increases as the amount is increased. However, 1
If it exceeds 0% by weight, the physical properties of the resin tend to be remarkably reduced, which may not be practical.

The organic peroxide (c) is represented by the following formula (1): R—O—O—R ′ (1) (where R and R ′ are the same or different, and Group, aryl group or aralkyl group) or the following formula (2)

[0015]

Embedded image

(Wherein the definitions of R and R 'are the same as described above) are preferably used.

The organic peroxides included in the above formulas (1) and (2) are known per se. Organic peroxide (c)
Include, for example, dicumyl peroxide, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,2 5-dimethyl-2,5-di (t-
Compounds included in the above formula (1) such as butylperoxy) hexyne-3 and compounds included in the above formula (2) such as dibenzoyl peroxide can be exemplified. Of these, dicumyl peroxide is particularly preferred. The compounding amount of the organic peroxide (c) is preferably 0.001 to 0.16% by weight, more preferably 0.005 to 0.14% by weight, based on the thermoplastic resin. If the organic peroxide is mixed in too much, the crosslinking of the thermoplastic resin takes precedence, and the structure of the composition becomes too hard and dense, so that the tendency of the biodegradability to decrease is increased.

The method of the present invention is carried out by kneading the above components (a), (b) and (c) at a temperature not lower than the softening point of the thermoplastic resin (a). Suitable kneading temperatures differ depending on the thermoplastic resin. For example, when the thermoplastic resin is polyethylene, a suitable kneading temperature is 160 to
In the range of 220 ° C. The kneading can be performed by a conventionally known kneading device such as an open-type mixing roll, a non-open-type Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, and the like. The biodegradable resin composition obtained by the method of the present invention further comprises (d) starch and / or a modified starch, (e) a metal salt, a metal in addition to the components (a), (b) and (c). It can contain at least one component of a metal compound selected from the group consisting of oxides and metal hydroxides and (f) oxidized wax. Examples of the starch or modified starch (d) include starch obtained from rice, corn, potato, sweet potato, wheat, or the like; or a product obtained by grafting a polymerizable monomer such as styrene to the starch; Modified starches such as those containing saccharides such as lactose and glucose, molasses, and casein sugar as main components and modified with organic substances which are taken in favor by living organisms can be mentioned.

The amount of the starch and / or modified starch is preferably from 5 to 70, based on the thermoplastic resin (a).
%, More preferably 7 to 20% by weight. Biodegradability increases as the amount of starch and / or modified starch increases. However, if it exceeds 70% by weight, the deterioration of the physical properties of the resin tends to be remarkably large, which may not be practical.

The metal compound (e) includes, for example, at least one metal salt of a metal selected from the group consisting of Na, K, Ca, Mg, Zn, Al, Mn and Fe;
Metal oxides or metal hydroxides are preferably used. As the metal salt, an inorganic acid salt or an organic carboxylate is preferable. As the organic carboxylate, a higher aliphatic carboxylate is particularly preferred. As the inorganic acid, for example, sulfuric acid,
Hydrochloric acid, carbonic acid and the like are preferable, and as the higher aliphatic carboxylic acid, a saturated aliphatic carboxylic acid having 10 to 30 carbon atoms or an unsaturated aliphatic carboxylic acid is preferred. As the metal, iron, aluminum and the like are particularly preferable. These metal compounds may be used alone or in combination of two or more. In particular, when a metal salt of an inorganic acid and a metal salt of a higher aliphatic carboxylic acid are used in combination, the biodegradability is significantly improved.

The amount of the metal compound is preferably 0.1 to 30% by weight, more preferably 0.3 to 10% by weight, based on the thermoplastic resin (a). The biodegradability increases as the amount of the metal compound increases. However, if it exceeds 30% by weight, the physical properties of the resin tend to be significantly reduced, which is not practical. As the oxidized wax (f), a commercially available product that can be obtained as an oxide of a wax can be used as it is. The compounding amount of the oxidized wax is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight, based on the thermoplastic resin.

When the above-mentioned components (d), (e) and (f) having an optional component are used, in the same manner as described above, at a temperature not lower than the softening point of the thermoplastic resin of the component (a), a),
It is advantageous to knead the components (b) and (c). The components (a) to (c) and (d) to (f) can be preliminarily mixed in any combination of two or more components, or can be prepared as a master batch.

The biodegradable resin composition obtained by the method of the present invention may be, for example, a film, a sheet, a tape, a yarn, a string,
Packaging materials such as nets, industrial materials such as civil engineering and marine products, shopping bags, garbage bags, light and heavy packaging bags, diaper films, agricultural multi-films, soft drink carriers,
Sandbags, curing sheets, straight-line nets, food containers, tableware,
It can be in various forms such as containers such as buckets, toys, medical equipment and the like. These molded articles can be produced by various molding methods such as masterbatch, extrusion molding, injection molding, inflation molding, calendar molding, blow molding, and rotational molding.

The biodegradable resin composition of the present invention may be a rubber, a plasticizer, a lubricant, an ultraviolet absorber, another antioxidant, a foaming agent, a crosslinking agent, an antistatic agent, or the like, without departing from the scope of the present invention. It may contain additives such as agents, anti-violence agents, flame retardants, coloring agents, fillers, and the like.

The biodegradable resin composition obtained by the present invention comprises:
When placed in contact with a biodegradable medium, such as soil, garbage, sludge, or compost, it undergoes biodegradation by microorganisms present in the biodegradable medium and gradually loses its original form. Further, since the biodegradable resin composition obtained in the present invention also has a property of decomposing by ultraviolet rays, for example, after being decomposed by irradiation of sunlight, if buried in soil or the like,
Its biodegradability is achieved more quickly. The contact temperature with the biodegradable medium is preferably about 10 to 45 ° C. Soil, garbage and compost can be used alone or mixed together. The resin composition and these biodegradable media, such as soil, should be placed in as close contact as possible. For example, when the resin composition is in the form of a film, it is desirable that both sides of the film come into contact with the biodegradable medium while the film is stretched well.

[0026]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to only such Examples.

Example 1 (1). Low density polyethylene (manufactured by Nippon Petrochemical Co., Ltd.)
F-31N), 43% by weight of a modified starch obtained by treating the surface of corn starch with a silane coupling agent,
6% by weight of rapeseed oil boiled and oxidized for 2 hours and 8% by weight of calcium oxide, 5.0% by weight of aluminum hydroxide, 5.0% by weight of aluminum sulfate, iron stearate
5.0% by weight, 5.0% by weight of oxidized wax and 0.2% by weight of dicumyl peroxide were blended and mixed by dry blending using a Hensyl mixer. This mixture was melt-mixed with an extruder to obtain a high-concentration master batch pellet.

This masterbatch pellet was added to low-density polyethylene without additives (F-31, manufactured by Nippon Petrochemical Co., Ltd.).
N) was dry blended at 10% by weight, and then a 50 μm thick film was produced by an inflation molding method using an extruder having a screw diameter of 40 mmφ.
Test specimens were formed from this film. The amount of each component in the test piece was 4.3% by weight of modified starch and 0.6 of oxidized rapeseed oil.
% By weight, 0.8% by weight of calcium oxide, 0.5% by weight of aluminum hydroxide, 0.5% by weight of aluminum sulfate, 0.5% by weight of iron stearate, 0.5% by weight of oxidized wax
And dicumyl peroxide was 0.02% by weight.

(2) A test piece of the above film was buried in garbage and forest soil for about 5 months. The five-month-old garbage buried piece had few pores and a brown discolored part was observed by visual observation. In addition, the tensile strength and elongation of the 5-month-old garbage buried specimen were 94% respectively compared to the test specimen before burying.
And a value of 100%. On the other hand, the tensile strength and the elongation of the buried piece in the forest for 5 months were 92% and 73%, respectively, as compared with the test piece before burying. Furthermore, the oxidation initiation temperature of the 5-month buried piece of garbage and the 5-month buried piece of forest was 2
06.3 ° C and 209.4 ° C. The temperature of the test piece before embedding was 210.6 ° C. In addition, microscope F
The measurement results of the functional groups by T-IR were as shown in Table 1. Table 1 shows the concentration of each characteristic absorption peak as 147.
It was shown as an absorbance ratio to the absorbance at 0 cm ^-1 . In addition, each characteristic absorption peak is identified as follows. 1710 cm ^-1 : absorption by carboxylic acid generated by oxidative deterioration and decomposition 1745 cm ^-1 : decrease and deterioration of carbonyl group derived from oil, absorption of ester generated by decomposition 880 cm ^-1 : by peroxide (-OO-) Absorption 1640 cm ^-1 : Absorption by carbon-carbon double bond (> C = C <)

Example 2 (1) The procedure of Example 1 was repeated, except that the masterbatch pellets were added to low-density polyethylene without additives in an amount of 20% by weight. The amount of each component in the test piece was 8.6% by weight of modified starch, 1.2% by weight of rapeseed oil, 1.6% by weight of calcium oxide, 1.0% by weight of aluminum hydroxide, and 1.
0% by weight, 1.0% by weight of iron stearate, 1.0% by weight of oxidized wax and 0.04% by weight of dicumyl peroxide. (2). The test piece of the film was buried in garbage and forest soil for about 5 months. The 5-month-old garbage buried piece had many pores, strong discoloration, and shrinkage was partially observed by visual observation. The tensile strength and the elongation of the 5-month-old garbage buried piece were 108% and 87%, respectively, as compared with the test piece before burying. On the other hand, the tensile strength and elongation of the buried specimens in the forest for 5 months were 1 unit less than the specimens before burying.
10% and 107%. Furthermore, the oxidation initiation temperature of the 5-month buried piece of garbage and the 5-month buried piece of forest was 2
06.0 ° C and 201.0 ° C. The temperature of the test piece before embedding was 208.3 ° C. In addition, microscope F
The measurement results of the functional groups by T-IR were as shown in Table 1. Table 1 shows the concentration of each characteristic absorption peak as 147.
It was shown as an absorbance ratio to the absorbance at 0 cm ^-1 .

Example 3 (1) A masterbatch containing 0.4% by weight of dicumyl peroxide was obtained in the same manner as in Example 1 (1). Others were performed similarly to Example 1. The amount of each component in the test piece was 4.3% by weight of modified starch, 0.6% by weight of rapeseed oil, 0.8% by weight of calcium oxide, 0.5% by weight of aluminum hydroxide, 0.5% by weight of aluminum sulfate. % By weight, 0.5% by weight of iron stearate, 0.5% by weight of oxidized wax and 0.02% by weight of dicumyl peroxide. (2). The test piece of the above film was buried in garbage and forest soil for about 5 months. The five-month-old garbage buried piece had voids partially by visual observation, and a brown discolored portion was observed. In addition, the tensile strength and elongation of the 5-month-old garbage buried specimen were 99% and 9% lower than that of the test specimen before burying.
It showed a value of 4%. On the other hand, the tensile strength and elongation of the 5-month-old buried specimen in the forest were 101% respectively as compared with the test specimen before burying.
And 94%. Furthermore, the oxidation start temperature of the 5-month buried piece of garbage and the 5-month buried piece of forest was 204.7, respectively.
° C and 207.3 ° C. The temperature of the test piece before embedding was 211.0 ° C. In addition, the microscope FT-I
The measurement results of the functional groups by R are as shown in Table 1. Table 1 shows that the concentration of each characteristic absorption peak is 1470 cm.
^It was shown as an absorbance ratio at ^-1 .

Example 4 (1) The procedure of Example 3 was repeated, except that the master batch pellets were mixed with 20% by weight of low-density polyethylene without additives. The amount of each component in the test piece was 8.6% by weight of modified starch, 1.2% by weight of rapeseed oil, 1.6% by weight of calcium oxide, 1.0% by weight of aluminum hydroxide, 1.0% by weight of aluminum sulfate. Wt% iron stearate 1.0 wt%, oxidized wax 1.0
% By weight and 0.08% by weight of dicumyl peroxide. (2). The test piece of the film was buried in garbage and in forest soil for about 5 months. The 5-month-old garbage buried piece had voids partially by visual observation, and deep discoloration and partial shrinkage were observed. The tensile strength and elongation of the 5-month-old garbage buried piece (portion without voids generated by burying) were 83% and 100%, respectively, as compared to the test piece before burying. On the other hand, the tensile strength and elongation of the buried specimens in the forest for 5 months were 106% and 94%, respectively, as compared with the test pieces before burying.
Met. Furthermore, the oxidation starting temperatures of the garbage 5 month buried piece and the forest 5 month buried piece were 195.5 ° C and 20 respectively.
3.9 ° C. The test piece before embedding was 20
6.4 ° C. The measurement results of the functional groups by the microscope FT-IR were as shown in Table 1. In Table 1,
The concentration of each characteristic absorption peak was shown as an absorbance ratio to the absorbance at 1470 cm ^-1 .

[0033]

[Table 1]

Example 5 (1). Low density polyethylene (Nippon Petrochemical Co., Ltd.)
F-31N), 43% by weight of a modified starch obtained by treating the surface of corn starch with a silane coupling agent, 6% by weight of soybean fat and 8% by weight of calcium oxide, 5.0% by weight of aluminum hydroxide, 5.0% by weight of aluminum sulfate %, 5.0% by weight of iron stearate, 5.0% by weight of oxidized wax and 0.4% by weight of dicumyl peroxide were mixed by dry blending using a Hensyl mixer.
This mixture was melt-mixed with an extruder to obtain a high-concentration master batch pellet.

The master batch pellets were added to low-density polyethylene without additives (F-31, manufactured by Nippon Petrochemical Co., Ltd.).
N) was dry blended with 20% by weight, and then a 50 μm thick film was produced by an inflation molding method using an extruder having a screw diameter of 40 mmφ.
Test specimens were formed from this film. The amount of each component in the test piece was 8.6% by weight of modified starch, 1.2% by weight of soybean oil, 1.6% by weight of calcium oxide, 1.0% by weight of aluminum hydroxide, 1.0% by weight of aluminum sulfate. %, 1.0% by weight of iron stearate, 1.0% by weight of oxidized wax and 0.08% by weight of dicumyl peroxide.

(2) A test piece of the above film was buried in forest soil for about 8 months. During that time, a film test piece was dug out at an appropriate interval, and the elongation at break and the absorbance of a characteristic absorption peak by FT-IR were measured. The results are shown in FIGS. 1, 2 and 3 of the accompanying drawings. In these figures, the curve B is the result when the film of the present invention is embedded in forest soil, and the curve A is the same as the above composition except that dicumyl peroxide is not blended. 3 shows the results when the comparative film from the above was buried in forest soil. In FIG. 1, the curve A ′ is the result when the film of the present invention is left indoors (in a dark place). It can be seen that the film of the present invention, when buried in soil, has a remarkably reduced elongation at break and a large increase in carbonyl groups and peroxide bonds.

Example 6 The same film as the film of the present invention used in Example 5 was prepared (B). Further, in the same manner as in Example 5, the films (C) and 0 of the present invention differed from the film of the present invention of Example 5 only in that the compounding amount of dicumyl peroxide was 0.12% by weight. A comparative film (D) was prepared separately except that it was .16% by weight. After heat treating these three films at 90 ° C. for 12 days in a gear oven,
It was immersed in distilled water for 4 hours. Thereafter, the water absorption of each film sample was measured. The results are shown in FIG. The films (B) and (C) of the present invention gradually absorb more water as the heat treatment time is longer, while the comparative film (D), which contains a larger amount of peroxide, absorbs more water than the film of the present invention. It can be seen that the amount is very small. It is presumed that the comparative film (D) had a cross-linking reaction that proceeded preferentially, the structure became dense, and the intrusion of moisture was reduced.

Example 7 The same film B of the present invention as used in Example 5, Comparative Film A and low density polyethylene (LDPE, F31
N) Comparative films A ″ were prepared. These films were subjected to a light deterioration test using a sunshine weather meter. The results are shown in FIG. 5. The results show that the light deterioration of the film A of the present invention is rapid. If the film of the present invention is buried in soil or the like after being subjected to such photodeterioration, the biodegradability is further promoted.

[0039]

According to the present invention, a novel biodegradable resin composition which is buried in soil, garbage or compost to promote biodegradation can be advantageously produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the embedding period of a film and the elongation at break.

FIG. 2 is a diagram showing a relationship between a burying period of a film and a characteristic absorption peak (1710 cm ⁻¹ ) by FT-IR.

FIG. 3 is a diagram showing a relationship between a burying period of a film and a characteristic absorption peak (880 cm ⁻¹ ) by FT-IR.

FIG. 4 is a diagram showing a relationship between a heat treatment time of a film and a water absorption amount.

FIG. 5 is a diagram showing a relationship between a heat treatment time of a film and light deterioration by a sunshine weather meter.

[Explanation of symbols]

 A Comparative film B Film of the present invention C Film of the present invention D Comparative film A 'Film of the present invention (room standing) A "Comparative film (polyethylene)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobunao Murakami 4-1-1-13 Honcho, Chuo-ku, Osaka-shi, Osaka Inside the Osaka Main Store of Takenaka Corporation (72) Inventor Takashi Hirayama 4- Kitaune, Kurashiki-shi, Okayama Prefecture 16-30 (72) Inventor Hitoshi Asabe 211-1 Chaya-cho, Kurashiki City, Okayama Prefecture (56) References JP-A-62-201952 (JP, A) JP-A-7-126461 (JP, A) 6-316655 (JP, A) JP-A-7-126449 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13 / 08 C08J 3/24

Claims (7)

(57) [Claims] (1) a thermoplastic resin, (b) an oil and / or
Or oxidized oil , where oil and oxidized oil are each an animal
Oils, vegetable oils and their oxidized oils, and (c)
A method for producing a biodegradable resin composition, comprising kneading an organic peroxide at a temperature equal to or higher than the softening temperature of the thermoplastic resin (a). 2. The method according to claim 1, wherein in addition to the components (a), (b) and (c), (d) starch and / or a modified starch is kneaded together. 3. In addition to the components (a), (b) and (c) or in addition to the components (a), (b), (c) and (d), (e) a metal salt, 3. The method according to claim 1, wherein a metal compound selected from the group consisting of a metal oxide and a metal hydroxide is kneaded together. 4. In addition to the components (a), (b) and (c), or the components (a), (b), (c) and (d)
In addition to the components, or (a), (b), (c),
The method according to any one of claims 1 to 3, wherein (f) an oxidized wax is further kneaded together with the components (d) and (e). 5. The organic peroxide (c) is represented by the following formula (1): R—O—O—R ′ (1) (where R and R ′ are the same or different, and Group, an aryl group or an aralkyl group) or the following formula (2): The method according to claim 1, wherein the definitions of R and R 'are the same as above. 6. The organic peroxide (C) is dicumyl peroxide, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t -Butylperoxy) hexane or 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-
3. The method of claim 1, wherein the number is 3. 7. The method according to claim 1, wherein the thermoplastic resin (a) is polyethylene and the kneading is performed at a temperature of 160 to 220 ° C.