JP2010006875A - Method for producing thermoplastic composition pellets and method for producing molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing thermoplastic composition pellets containing a vegetable material in a large amount but suitable for injection molding, and to provide a method for producing a molded article using the same. <P>SOLUTION: Provided is the method for producing pellets 56 containing the vegetable material in an amount of 50 to 95 mass%, wherein the total amount of the vegetable material and a thermoplastic resin is 100 mass%, characterized by having a mixing process for melting the thermoplastic resin and simultaneously mixing with the vegetable material by the use of a mixing and melting device 1, a crushing process for crushing the obtained mixture to obtain a crushed mixture 301, and a pelletizing process for press-compacting the crushed mixture to obtain the pellets, having at least one of an oil-adding process for adding an oil 403 to the vegetable material before the mixing process and an oil-adding process for adding the oil 403 to the crushed mixture before the crushed mixture is pelletized, and adding the oil in a total amount of 1 to 17 pts.mass per 100 pts.mass of the total amount of the vegetable material and the thermoplastic resin, in the oil-adding process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a thermoplastic composition pellet and a method for producing a molded body. More specifically, the present invention relates to a method for producing a thermoplastic composition pellet containing as much as 50 to 95% by mass of a plant material and a method for producing a molded body.

In recent years, plant materials such as kenaf that grow rapidly and have a large amount of carbon dioxide absorption are attracting attention from the viewpoints of reducing carbon dioxide emissions, fixing carbon dioxide, and the like, and are expected to be used in combination with resins.
However, it is particularly difficult to mix a large amount of plant material with the resin and to mold the resulting composite material. This is because it is difficult to give the composite material sufficient fluidity equivalent to that of conventional resins. The following Patent Documents 1 to 3 are known as techniques for handling composite materials containing a large amount of plant material.

JP-A-2005-105245 JP 2000-219812 A JP 2008-093956 A

In the above-mentioned Patent Document 1, when the content of kenaf fiber exceeds 50% by mass, the fluidity of the resin composition is remarkably lowered, so that there is a problem that a satisfactory product shape and product form cannot be obtained in injection molding. It has been shown to occur. That is, it has been shown that it is difficult to mix a large amount of plant material exceeding 50% by mass.
Moreover, in the said patent document 2, when a rosin and a plasticizer are not added to resin and only a plant fiber is mix | blended, it is difficult to disperse | distribute a vegetable fiber uniformly, and since affinity between resin and a vegetable fiber is bad, etc. It is shown that only materials with poor strength and the like, lack of uniformity of quality, and poor practicality can be obtained. That is, although a large amount of plant material of 50% by mass or more can be mixed, an additive is required.
Although the above-mentioned Patent Document 3 discloses a method for producing a molded body containing a large amount of plant material by 50% by mass using pelletized plant material, it is more suitable for injection molding. There is a need for thermoplastic compositions.

  The present invention has been made in view of the above, such as clogging of an apparatus or lack of a molded product obtained when used in an injection molding machine while containing a large amount of plant material as 50 to 95% by mass. It aims at providing the manufacturing method of the thermoplastic composition pellet suitable for the injection molding which prevented the malfunction, and the manufacturing method of a molded object using the same.

  An injection molding apparatus used industrially in injection molding is usually equipped with an automatic metering mechanism. The thermoplastic composition charged into the raw material inlet of the injection molding apparatus is weighed by the automatic metering mechanism and then injected into the mold by a certain amount based on the amount. It is preferable that the raw material charged in order for this automatic weighing mechanism to function sufficiently is pelletized.

  On the other hand, it is a material containing a large amount of vegetable material as 50 to 95% by mass, and the thermoplastic composition before undergoing the injection molding process is relatively brittle and easily deformed. In particular, the tendency is stronger in pellets formed by compaction as in the production method of the present invention. Such pellets may produce fine particles and powders due to a part of the pellets being lost due to handling or transportation. When the present inventors put such pellets containing fine particles and powder into the raw material charging port, it tends to cause a measurement defect, and easily causes a molding defect such as formation of a thin wall in the obtained molded product. It was found that it affects product quality and productivity. And it discovered that this problem could be solved by adding an oil component to the material (plant material and / or ground mixture) used at each process. In addition, it has been found that when oil is added to these materials, the flowability of the obtained thermoplastic composition pellets is improved and the impact resistance of the molded product is improved. It came to complete.

That is, the present invention is as follows.
(1) A thermoplastic composition containing a plant material and a thermoplastic resin, and 50 to 95% by mass of the plant material when the total of the plant material and the thermoplastic resin is 100% by mass A method for producing pellets, comprising:
A mixing step of mixing with the plant material while melting the thermoplastic resin using a mixing and melting apparatus;
A crushing step of crushing the mixture obtained in the mixing step to obtain a crushing mixture;
A pelletizing step of pressing and solidifying the crushed mixture to obtain pellets,
Further, at least one of an oil addition step for adding oil to the plant material before the mixing step, and an oil addition step for adding oil to the crushed mixture before the crushed mixture becomes the pellets. With an oil addition process,
In the oil component addition step, when the total of the plant material and the thermoplastic resin is 100 parts by mass, the thermoplastic component is added so that the total amount of oil is 1 to 17 parts by mass. Pellet manufacturing method.
(2) The method for producing a thermoplastic composition pellet according to (1), wherein the oil is a paraffinic oil.
(3) The pelletizing step uses a roller-type molding machine provided with a die and a roller that rotates in contact with the die, and after pressing the crushed mixture into the die by the roller, the pellet is extruded from the die. The method for producing a thermoplastic composition pellet according to the above (1) or (2), which is a step of forming the pellet.
(4) The mixing and melting apparatus includes a mixing chamber for performing the mixing and a mixing blade disposed in the mixing chamber,
The thermoplastic resin according to any one of (1) to (3), wherein the mixing step mixes the thermoplastic resin melted by rotation of the mixing blade in the mixing chamber and the plant material. Method for producing composition pellets.
(5) The said vegetable material is a manufacturing method of the thermoplastic composition pellet in any one of said (1) thru | or (4) which is kenaf.
(6) The thermoplastic composition pellet manufacturing method according to any one of (1) to (5), wherein the thermoplastic resin is polypropylene and / or an ethylene / propylene copolymer.
(7) The thermoplastic composition pellet obtained by the method for producing a thermoplastic composition pellet according to any one of the above (1) to (6) is injection-molded to obtain a molded body. Manufacturing method of a molded object.

According to the method for producing a thermoplastic composition pellet of the present invention, when the plant material is used in an injection molding machine while containing a large amount of plant material at 50 to 95% by mass, the device is clogged, or the resulting molded product is thin. Thus, a thermoplastic composition pellet suitable for injection molding in which the above problems are prevented can be obtained. In particular, the provision of the oil component addition step suppresses the collapse of the thermoplastic composition pellets obtained compared to the case where the oil component addition is not performed, and the thermoplastic composition pellets suitable for weighing during injection molding are obtained. Further, by obtaining the thermoplastic composition pellets, excellent moldability can be obtained without causing a lack of thickness in the molded body, and is higher than the case of using the thermoplastic composition pellets to which no oil is added. Mechanical properties are manifested.
In the case where the oil is a paraffinic oil, a particularly excellent oil addition effect can be obtained.
The pelletizing step is a step of using a roller-type molding machine equipped with a die and a roller rotated in contact with the die, pressing the crushed mixture into the die with a roller, and then extruding the die to form a pellet. In this case, pelletization can be performed without requiring heating for softening or melting the thermoplastic resin. For this reason, the thermal history with respect to a thermoplastic resin composition can be suppressed, and the molded object by the thermoplastic composition pellet obtained can express the outstanding mechanical characteristic.
When the mixing step is a step of mixing the thermoplastic resin melted by the rotation of the mixing blade and the plant material in the mixing chamber, mixing can be performed particularly in a short time, and heating from the outside can be performed. Therefore, a mixture containing 50 to 95% by mass and many plant materials can be obtained.
When the plant material is kenaf, kenaf is an extremely fast growing annual grass and has an excellent carbon dioxide absorbability, so that it can contribute to the reduction of the amount of carbon dioxide in the atmosphere and the effective use of forest resources.
When the thermoplastic resin is polypropylene and / or ethylene / propylene copolymer, a thermoplastic composition pellet having excellent environmental characteristics can be obtained, and high mechanical characteristics can be obtained.
According to the method for producing a molded article of the present invention, a molded article made of a thermoplastic composition containing a large amount of plant material at 50 to 95% by mass can be obtained by injection molding. Furthermore, a molded body excellent in moldability and impact resistance can be obtained.

Hereinafter, the present invention will be described in detail.
[1] Manufacturing method of thermoplastic composition pellet The manufacturing method of the thermoplastic composition pellet of the present invention includes a plant material and a thermoplastic resin, and the total of the plant material and the thermoplastic resin is 100 masses. %, A method for producing a thermoplastic composition pellet containing 50 to 95% by mass of the plant material,
A mixing step of mixing with the plant material while melting the thermoplastic resin using a mixing and melting apparatus;
A crushing step of crushing the mixture obtained in the mixing step to obtain a crushing mixture;
A pelletizing step of pressing and solidifying the crushed mixture to obtain pellets,
Further, at least one oil addition step of an oil addition step of adding oil to the plant material before the mixing step and an oil addition step of adding oil to the crushed mixture before the pelletizing step. Prepared,
The oil component adding step is characterized in that when the total amount of the plant material and the thermoplastic resin is 100 parts by mass, the oil component is added in a total amount of 1 to 17 parts by mass.

The “mixing step” is a step of mixing with the plant material while melting the thermoplastic resin using a mixing and melting apparatus.
The “plant material” is a material derived from a plant. These plant materials include kenaf, jute hemp, manila hemp, sisal hemp, husk, cocoon, cocoon, banana, pineapple, coconut palm, corn, sugar cane, bagasse, palm, papyrus, cocoon, esparto, sabaigrass, wheat, rice, bamboo And plant materials obtained from various plants such as various conifers (such as cedar and cypress), broad-leaved trees and cotton. This plant material may use only 1 type and may use 2 or more types together. Of these, kenaf is preferred. This is because kenaf is an annual plant that grows very fast and has excellent carbon dioxide absorptivity, which contributes to reducing the amount of carbon dioxide in the atmosphere and effectively using forest resources.

Moreover, the site | part of the plant body used as said plant material is not specifically limited, Any site | part which comprises plant bodies, such as a non-wood part, a wood part, a leaf part, a stem part, and a root part, may be sufficient. Furthermore, only a specific part may be used and two or more different parts may be used in combination.
Furthermore, the shape of the plant material (plant material before mixing) contained in the thermoplastic composition pellet of the present invention is not particularly limited, and may be fibrous or non-fibrous (powder, crushed) Shape, chip shape, and indeterminate shape).

In addition, the kenaf in this invention is an early-growing annual grass which has a wooden stem, and is a plant classified into the mallow family. Hibiscus cannabinus and hibiscus sabdariffa etc. in scientific names are included, and further, red, hemp, Cuban kenaf, western hemp, taikenaf, mesta, bimli, ambari and bombay hemp etc. are included in common names.
The jute in the present invention is a fiber obtained from jute hemp. This jute hemp shall include hemp and linden plants including jute (Chorus corpus capsularis L.), and hemp (Tunaso), Shimatsunaso and Morohaya.

The shape of the plant material {plant material before mixing} is not particularly limited, and examples thereof include fibrous and non-fibrous forms. Among these, non-fibrous forms include powder forms (including granular and spherical shapes), chip shapes (including plate shapes and flake shapes), and irregular shapes (including pulverized material shapes). These may use only 1 type and may use 2 or more types together.
Among the above, the fibrous plant material (hereinafter also simply referred to as “vegetable fiber”) is a fiber taken out from the plant body, and the ratio of the diameter (fiber diameter) t to the length (fiber length) L. L / t is 5.0 to 20,000. In this vegetable fiber, the fiber length L is usually 0.5 to 300 mm, and the fiber diameter t is usually 0.01 to 1 mm. This fiber length is a value (L) measured on a measuring scale by stretching a single plant fiber straight without stretching, as in the direct method in JIS L1015. On the other hand, a fiber diameter is the value (t) which measured the fiber diameter in the center of the fiber length direction using the optical microscope about the vegetable fiber which measured fiber length.

Furthermore, the average fiber length and the average fiber diameter of the vegetable fiber are not particularly limited, but the average fiber length is preferably 20 mm or less. By using a vegetable fiber having an average fiber length of 20 mm or less, the above-described effect by using the vegetable fiber can be better obtained. The average fiber length is more preferably 1 to 15 mm, further preferably 1.5 to 10 mm, and particularly preferably 2 to 7 mm. This average fiber length is determined according to JIS L1015 by taking out single fibers one at a time by the direct method, stretching straight without stretching, and measuring the fiber length on a measuring scale. It is the measured average value.
On the other hand, the average fiber diameter is preferably 0.2 mm or less. By using vegetable fibers having an average fiber diameter of 0.2 mm or less, the above-mentioned effect by using vegetable fibers can be obtained better. The average fiber diameter is more preferably 0.01 to 0.15 mm, and particularly preferably 0.01 to 0.1 mm. This average fiber diameter is an average value measured for a total of 200 fibers by taking out single fibers at random and measuring the fiber diameter at the center in the length direction of the fibers using an optical microscope.

Further, the non-fibrous plant material (hereinafter, also simply referred to as “non-fibrous plant material”) is a plant material in a form not included in the fibrous form taken out from the plant body. Although the size is not particularly limited, for example, the maximum length (maximum particle size in the case of a granule) is 20 mm or less (usually 0.1 mm or more, further 0.3 to 20 mm, and further 0.3 to 15 mm, In particular, the thickness is preferably 0.5 to 10 mm.
Furthermore, when the shape is powdery, the average particle diameter is 5.0 mm or less (usually 0.1 mm or more, more preferably 0.2 to 5.0 mm, even more preferably 0.3 to 4.0 mm, particularly 0.3 to 3.0 mm, particularly 0.5 to 2.0 mm) is preferable. The average particle size is a value of D50 in the particle size distribution measured by a particle size distribution measuring device.
In addition, in the thermoplastic composition pellet obtained by this method, the shape and size of the plant material before mixing may or may not be maintained as it is in the thermoplastic resin composition. The case where it is not maintained includes a case where it is further finely pulverized during mixing and included in the thermoplastic composition pellets.

Moreover, when using kenaf as a vegetable material, kenaf fiber is mentioned as said vegetable fiber, A kenaf core powder is mentioned as said non-fibrous vegetable material. In the method for producing a thermoplastic composition pellet of the present invention, a non-fibrous vegetable material can be used as described above. That is, kenaf core powder can be used in kenaf.
This kenaf is composed of an outer layer part called bast and a core part called core. Among these, bast is highly useful because it has tough fibers, whereas the core is kenaf. Although it accounts for as much as 60% by volume, it cannot be made into vegetable fiber. Furthermore, since the apparent specific gravity is small and bulky, handling is poor, kneading with a resin or the like is difficult, and the core is often discarded or made into fuel. However, according to this method, kenaf core can be used as a plant material.

  The “thermoplastic resin” is a resin having thermoplasticity. The thermoplastic resin is not particularly limited, and various types can be used. Examples of the thermoplastic resin include polyolefin (polypropylene, polyethylene, etc.), polyester resin {(aliphatic polyester resin such as polylactic acid, polycaprolactone, polybutylene succinate), (polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, etc. Aromatic polyester resin)}, polystyrene, acrylic resin (resin obtained using methacrylate and / or acrylate, etc.), polyamide resin (nylon etc.), polycarbonate resin, polyacetal resin, ABS resin and the like. These may use only 1 type and may use 2 or more types together.

Further, among the polyester resins, polyester resins having biodegradability (hereinafter, also simply referred to as “biodegradable resins”) are preferable. Biodegradable resins include (1) homopolymers of hydroxycarboxylic acids such as lactic acid, malic acid, glucose acid and 3-hydroxybutyric acid, and co-polymerization using at least one of these hydroxycarboxylic acids Caprolactone-based aliphatic polyesters, such as hydroxycarboxylic acid-based aliphatic polyesters, (2) polycaprolactone, and copolymers of at least one of the above hydroxycarboxylic acids with caprolactone, (3) poly And dibasic acid polyesters such as butylene succinate, polyethylene succinate and polybutylene adipate.
Among these, polylactic acid, a copolymer of lactic acid and other hydroxycarboxylic acid excluding lactic acid, polycaprolactone, and a copolymer of caprolactone with at least one of the hydroxycarboxylic acids are particularly preferable. Polylactic acid is preferred. These biodegradable resins may be used alone or in combination of two or more. The lactic acid includes L-lactic acid and D-lactic acid, and these lactic acids may be used alone or in combination.

  Further, as the thermoplastic resin, a thermoplastic elastomer can be used alone or in combination with another thermoplastic resin. Examples of the thermoplastic elastomer include olefin thermoplastic elastomer, styrene thermoplastic elastomer, urethane elastomer, polyester elastomer, polyamide elastomer and the like. Of these, olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers are preferred.

The form of the olefinic thermoplastic elastomer is not particularly limited, but includes an olefinic resin component (functioning as a hard segment) and a rubber component (functioning as a soft segment), and the rubber component is dispersed in the olefinic resin component Is preferred.
Among these, the olefin resin component is not particularly limited except that it is a resin mainly composed of olefin. Examples of the olefin resin component include olefin homopolymers, copolymers containing olefins (constituent units derived from 70 mol% or more of olefins when the total constituent units constituting the olefin copolymer are 100 mol%) Copolymer). Examples of the former (olefin homopolymer) include polyethylene, polypropylene, and ethylene / propylene copolymers (such as ethylene / propylene random copolymers). On the other hand, examples of the latter (an olefin-containing copolymer) include an ethylene / vinyl acetate copolymer and an ethylene / alkyl acrylate copolymer. These olefin resin components may be used alone or in combination of two or more.
The composition of the rubber component is not particularly limited, and various rubber components can be used. That is, for example, olefin rubber (EPR, EPDM, etc.), styrene rubber, urethane rubber, acrylic rubber and the like can be mentioned. These may use only 1 type and may use 2 or more types together. Among these rubber components, olefin rubber and styrene rubber are preferable.

  Styrenic thermoplastic elastomers include aromatic vinyl compounds {styrene, alkyl-substituted styrene (α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, etc.), vinyl It is a copolymer containing structural units derived from naphthalene, vinyl anthracene, etc.}, and is usually derived from this aromatic vinyl compound {usually 5 mol% (usually 50 mol% or less) in all structural units]. Contains over} is contained as an aromatic vinyl polymer block and functions as a hard segment. The styrene thermoplastic elastomer may be hydrogenated or not hydrogenated, but a hydrogenated styrene thermoplastic elastomer is preferable. The polymer portion other than the aromatic vinyl polymer block is usually formed using a conjugated diene (butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc.). .

  Examples of the styrenic thermoplastic elastomer include hydrogenated styrene / butadiene random copolymer (HSBR), styrene / ethylene / butylene / styrene block copolymer (SEBS, hydrogenated styrene / butadiene block copolymer), and styrene.・ Ethylene / propylene / styrene block copolymer (SEPS, hydrogenated styrene / isoprene block copolymer), styrene / butadiene / styrene block copolymer (SBS), styrene / isoprene / styrene block copolymer (SIS) Etc.

  Among the above-mentioned various thermoplastic resins, polyolefins, polyester resins, and mixed resins with other resins including polylactic acid among polyester resins {polylactic acid alloy (polystyrene, ABS, nylon, polycarbonate, polypropylene, and polybutylene succinate) At least one of them and a mixed resin of polylactic acid, etc.)}. Of these, polyolefin is preferred, and at least one of polypropylene (homopolymer), a mixed resin of polyolefin containing polypropylene, and an olefin copolymer resin containing a structural unit derived from propylene is particularly preferred. Among these, the mixed resin of polyolefin containing polypropylene includes a mixed resin of polypropylene and polyethylene. Furthermore, examples of the olefin copolymer resin containing a structural unit derived from propylene include an ethylene / propylene copolymer (including a random copolymer and a block copolymer). These polyolefins may use only 1 type and may use 2 or more types together. Among these, polypropylene (homopolymer) and / or ethylene / propylene copolymer are particularly preferable.

Further, in this mixing step, a part of the thermoplastic resin can be acid-modified thermoplastic resin. That is, the above-mentioned acid-modified thermoplastic resins (non-acid-modified thermoplastic resins) and acid-modified thermoplastic resins can be used in combination.
The acid-modified thermoplastic resin is a thermoplastic resin having an acid group. Examples of the acid-modified thermoplastic resin include those obtained by introducing an acid group into a thermoplastic resin (hereinafter, a polymer in which no acid group is introduced is also referred to as “base polymer”). As this base polymer, 1 type (s) or 2 or more types of various thermoplastic resins mentioned as said thermoplastic resin can be used. Among these, polyolefin is preferable like the non-acid-modified thermoplastic resin.

  Furthermore, the base polymer is preferably the same quality as the non-acid-modified thermoplastic resin. This “homogeneous” means [i] the same type of thermoplastic resin and the same structural unit (monomer unit), and [ii] the same type of thermoplastic resin, the structural unit being It means different, or [iii] the same or different types of thermoplastic resins, which are at least one kind of the same structural unit and are compatible with each other. “The same kind of thermoplastic resin” means common in the classification of polyolefin, polyester resin, acrylic resin, polyamide resin, polycarbonate resin, polyacetal resin, and the like.

  As said [i], it is the same homopolymer or copolymer, Comprising: The chemical properties or physical properties, such as molecular weight and a viscosity, differ. Of these, examples of the copolymer include a case in which two or more common structural units are present and the proportions thereof are different. Examples of [ii] include a case where one is polyethylene and the other is polypropylene. Examples of the above [iii] include a case where one is polyethylene and the other is an ethylene / propylene copolymer. In said [ii] and [iii], it is preferable that the main structural unit which occupies 50 mol% or more of each structural unit of a thermoplastic resin (B) and a base polymer is the same.

  The type of acid group forming the acid-modified thermoplastic resin is not particularly limited, but is usually a carboxylic anhydride residue (—CO—O—OC—) and / or a carboxylic acid residue (—COOH). This acid group may be introduced at the copolymerization stage or may be grafted. The acid group may be introduced by any compound, and examples of the compound include maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, maleic acid, itaconic acid. , Fumaric acid, acrylic acid, and methacrylic acid. These may use only 1 type and may use 2 or more types together. Of these, maleic anhydride and itaconic anhydride are preferred, and maleic anhydride is particularly preferred.

  Although the amount of acid groups introduced into the acid-modified thermoplastic resin is not particularly limited, the acid value is preferably 5 or more. This is because a high addition effect can be obtained while suppressing the addition amount of the acid-modified thermoplastic resin. As for this acid value, 10-80 are more preferable, 15-70 are still more preferable, and 20-60 are especially preferable. This acid value is according to JIS K0070. Furthermore, the weight average molecular weight is preferably 10,000 to 200,000. Thereby, while suppressing the property change to the whole thermoplastic resin composition, the high addition effect is acquired and the further outstanding impact resistance can be provided. The weight average molecular weight is more preferably 15,000 to 150,000, still more preferably 25,000 to 120,000, and particularly preferably 35,000 to 100,000. The weight average molecular weight is based on the GPC method.

  The amount ratio of the plant material and the thermoplastic resin to be mixed in the mixing step is not limited as long as the ratio of the plant material in the obtained mixture is 50 to 95% by mass, but 50 to 90% by mass. Preferably, 51-85 mass% is more preferable, 52-80 mass% is still more preferable, and 53-75 mass% is especially preferable. Within the above range, it is particularly easy to obtain the effects of improving the moldability and impact resistance by providing the oil addition step of the present invention.

  The “mixing and melting apparatus” is an apparatus for mixing with a plant material while melting a thermoplastic resin, and excluding an extrusion type apparatus. The type of the mixing and melting apparatus is not particularly limited, but the mixing and melting apparatus includes a mixing chamber for mixing and a mixing blade disposed in the mixing chamber, and is a thermoplastic melted by the rotation of the mixing blade in the mixing chamber. It is preferable that the resin and the plant material can be mixed. As such a mixing and melting apparatus, the following mixing and melting apparatus is particularly preferable. When this mixing and melting apparatus is used, the plant material and the thermoplastic resin can be mixed particularly well.

  This mixing and melting apparatus (hereinafter, FIG. 1 and FIG. 3 (FIG. 3 refers to FIG. 1 of the pamphlet of International Publication No. 04/076044 obtained from the Patent Digital Library of the Patent Office) and FIG. As the reference}, reference is made to the International Publication No. 04/076044 pamphlet obtained from the electronic library), and the mixing and melting apparatus 1 described in the International Publication No. 04/076044 pamphlet is preferable. That is, the mixing and melting apparatus 1 includes a material supply chamber 13, a mixing chamber 3 connected to the material supply chamber 13, and a rotation provided rotatably through the material supply chamber 13 and the mixing chamber 3. A shaft 5, and a spiral blade 12 that is disposed on the rotating shaft 5 in the material supply chamber 13 and conveys the mixed material (vegetable material or the like) supplied to the material supply chamber 13 to the mixing chamber 3. A mixing and melting apparatus provided with mixing blades 10a to 10f disposed on the rotary shaft 5 in the mixing chamber 3 and mixing the mixed material is preferable.

  By using the mixing and melting apparatus, the mixed material is put into the mixing and melting apparatus 1 (material supply chamber 13), and the mixing blades 10a to 10f of the mixing and melting apparatus 1 are rotated, whereby the plant material and the thermoplastic resin {first In this method, the thermoplastic polymer component (C)} is further struck and pushed toward the inner wall of the mixing chamber 3 and is thermoplasticized in a short time by the energy (heat amount) that the materials collide with each other. The resin {in the first method, the thermoplastic polymer component (C)} is further softened, further melted, mixed with the plant material, and further kneaded. Moreover, the fluidity | liquidity which can be injection-molded is expressed in the thermoplastic composition pellet obtained.

The mixing blades 10a to 10f are arranged on the rotating shaft 5 at an attachment angle so as to oppose each other in the axial direction at a portion of the rotating shaft 5 at a constant angular interval in the circumferential direction and to reduce the facing interval in the rotating direction. It is constituted by at least two mixing blades (10a to 10f) provided, and the mounting angle of the mixing blades 10a to 10f with respect to the rotary shaft 5 is the root portion of the mixing blades 10a to 10f attached to the rotary shaft 5 To the radially outer tip, and preferably, the mixing blades 10a to 10f have a rectangular plate shape.
More preferably, the mixing chamber further includes a mixing chamber cooling means that can circulate a cooling medium through the walls constituting the mixing chamber. With this configuration, an excessive temperature rise in the mixing chamber can be suppressed, and decomposition and thermal deterioration of the thermoplastic resin can be suppressed (and further prevented).

Various conditions in the above “mixing” are not particularly limited. For example, the temperature during mixing is not particularly limited, but the temperature of the outer wall of the mixing chamber is 200 ° C. or lower (more preferably 150 ° C. or lower, more preferably 120 ° C. or lower). It is preferable to control, and it is preferable to control to 50 degreeC or more (more preferably 60 degreeC or more, still more preferably 80 degreeC or more). The temperature is preferably reached within 10 minutes (more preferably within 5 minutes). Furthermore, the temperature range is preferably within 15 minutes (more preferably within 10 minutes). Deterioration of the thermoplastic resin can be effectively suppressed by increasing the temperature in a short time and further finishing the mixing in a short time.
The temperature is preferably controlled by controlling the rotation speed of the mixing blade of the mixing and melting apparatus. More specifically, it is preferable to control the rotation speed at the tip of the mixing blade to be 5 m / sec to 50 m / sec. By controlling within this range, it is possible to more strongly (more uniformly) mix with the plant material while efficiently softening and melting the thermoplastic resin.

  Furthermore, although the end point in this mixing is not specifically limited, it can be determined by a change in torque applied to the rotating shaft. That is, it is preferable to measure the torque applied to the rotating shaft and stop mixing after the torque reaches the maximum value. Thereby, the mixed materials can be mixed with each other with good dispersibility. Furthermore, it is more preferable to stop the mixing after the torque starts to decrease after reaching the maximum value of the torque. It is particularly preferable to stop the mixing in a torque range of 40% or more (particularly preferably 50 to 80%) with respect to the maximum torque. As a result, the mixed materials can be mixed with each other with good dispersibility, and the mixture (thermoplastic resin composition before crushing) can be taken out from the inside of the mixing chamber at a temperature of 160 ° C. or more. Can be more reliably prevented from adhering to and remaining.

The “crushing step” is a step of crushing the mixture obtained in the mixing step to obtain a crushed mixture. The method for crushing the mixture is not particularly limited. For example, a dry crushing method and a wet crushing method can be used, but a dry crushing method is preferable. This is because the dry method does not require drying of the plant material contained in the mixture by moisture absorption and water absorption.
The crusher (reference numeral 300 in FIG. 1) that can be used for crushing may be a shear crusher, a cutting crusher, an impact crusher, or a compression crusher. It may be a type crusher, or may be a crusher by another method. That is, examples of the crusher include a cutter mill, a turbo mill, a feather mill, a rotoplex mill, a rubber chopper, a hammer mill, and a jaw crusher. These crushers may be used independently and may use 2 or more types together. As a case of using together, after crushing a lump with one crusher and obtaining a crush material, the case where the crush material obtained with another crusher is further subdivided is mentioned.
Among these, a shearing type crusher is preferable because it can be more finely crushed (pulverized) and it is easier to ensure the optimum particle size in the present method.

Although the magnitude | size of a crushing mixture (code | symbol 301 of FIG. 1) is not specifically limited, Although it should just be able to use for the pelletization process mentioned later, it is preferable that a maximum side length is 25 mm or less (usually 1 mm or more). 20 mm is more preferable, 1-15 mm is still more preferable, and 2-7 mm is especially preferable. If it is this range, it is excellent in the pellet productivity in a pelletization process, and also in the obtained molded object, the reinforcement effect by a vegetable material can be acquired especially favorably.
When the mixture is pulverized to a powder by a pulverizer instead of a pulverizer, the reinforcing effect of the thermoplastic resin strength due to the inclusion of the plant material tends to be difficult to draw out sufficiently. For this reason, it is preferable to crush to the appropriate size.
Furthermore, in the crushing step, it is preferable to suppress an increase in temperature due to crushing, and the temperature of the mixture during crushing is particularly preferably 100 ° C. or lower (usually 0 ° C. or higher, more preferably 80 ° C. or lower). Within this range, deterioration of the thermoplastic resin can be effectively suppressed, and the mechanical properties of the resulting molded product can be maintained high.

  The “pelletizing step” is a step of obtaining a pellet by pressing and crushing the crushed mixture. In this way, by pressing and solidifying without heating, and pelletizing, for example, compared to the case where the mixture obtained in the mixing step is melted again and pelletized using a general method such as a twin screw extruder. Further, since the thermal history of the mixture can be reduced, the mechanical properties of the obtained molded body can be maintained higher.

  In the pelletizing step of pressing and solidifying without heating and pelletizing, it is particularly preferable to use various compression molding methods, rather than using any apparatus and means. Examples of the compression molding method include a roller molding method and an extruder molding method. The roller-type molding method is a method using a roller-type molding machine, in which a mixture is pressed into a die by a roller rotated in contact with the die, and then extruded from the die and molded. Examples of the roller type molding machine include a disk die type (roller disk die type molding machine) and a ring die type (roller ring die type molding machine) having different die shapes. On the other hand, the extruder type molding method is a method using an extruder type molding machine. After the mixture is pressed into the die by the rotation of the screw auger, the mixture is extruded from the die and molded. Among these compression molding methods, a method using a roller disk die molding method is particularly preferable. The roller disk die type molding machine used in this compression molding method is particularly suitable because of its high compression efficiency.

Furthermore, in this method, it is particularly preferable to pelletize by using the following specific roller disk die type molding machine 500 (the main part is illustrated in FIG. 2). That is, a disk die 51 having a plurality of through holes 511, a press roller 52 that rolls on the disk die 51 and pushes an uncompressed material (mixture) into the through hole 511, and the press roller 52 The disk die 51 has a main rotation shaft insertion hole 512 that is penetrated in the same direction as the through hole 511, and the main rotation shaft 53 is the main rotation shaft 53. The press roller fixing shaft 54 is inserted through the insertion hole 512 and perpendicular to the main rotation shaft 53, and the press roller 52 is rotatably supported by the press roller fixing shaft 54 so as to rotate the main rotation. A roller disk die molding machine (pelletizing apparatus) 500 having a roller disk die molding unit 50 that is rolled on the surface of the disk die 51 as the shaft 53 rotates.
In this roller disk die type molding machine 500, in addition to the above configuration, it is preferable that the press roller 52 further has irregularities 521 on the surface. Further, it is preferable to include a cutting blade 55 that is rotated in accordance with the rotation of the main rotating shaft 53.

In the roller disk die type molding machine 500, for example, in FIG. 2, the crushing mixture introduced from above the main rotating shaft 53 is caught by the surface irregularities 521 provided in the press roller 52 and pushed into the through holes 511, and the disk die Extruded from the back side of 51. The extruded string-like mixture is cut into an appropriate length by a cutting blade 55, pelletized, dropped downward, and recovered as a thermoplastic composition pellet (reference numeral 56 in FIG. 1).
The shape and size of the pellets to be obtained are not particularly limited, but are preferably columnar (other shapes may be used, but columnar is preferable). The maximum length is preferably 1 mm or more (usually 20 mm or less), more preferably 1 to 10 mm, and particularly preferably 2 to 7 mm.

  The “oil adding step” is a step of adding oil to the plant material used in the mixing step before the mixing step (hereinafter simply referred to as “oiling”) (hereinafter also simply referred to as “pre-mixing oil adding step”). ) And an oil addition step (hereinafter also simply referred to as “pre-pelletization oil addition step”) in which oil is added to the crushed mixture before becoming pellets. These steps may be provided with either one or both.

  The pre-mixing oil addition step of the oil addition step is a step of adding oil to the plant material. When the pre-mixing oil component addition step is provided, the oil component may be added at any stage as long as it is before the mixing step. That is, for example, before the mixing step, when the plant material is processed (cutting, pulverizing, pelletizing, etc.) so as to be easily used in the mixing step, it may be oiled before the processing. It may be oiled in, may be oiled after processing, or may be oiled between these. Examples of the case of processing the plant material include a step of cutting the plant material, a step of pulverizing the plant material, a step of pressing and cutting the cut or pulverized plant material, and the like. It is done. Among these steps, in particular, when the cutting step and the pelletizing step are provided, it is preferable to add an oil component to the plant material before these steps. Thereby, cutting and pelletization can also be performed more smoothly.

  Further, the pre-pelletizing oil addition step of the oil addition step is a step of adding oil to the crushed mixture before the crushed mixture becomes pellets. When this pre-pelletizing oil component addition step is provided, the oil component may be added at any stage before the pulverized mixture is pelletized. That is, for example, oil may be added to the crushed mixture before the crushed mixture is charged into the pelletizing apparatus, or oiled in the process of pelletizing the crushed mixture charged into the pelletizing apparatus in the apparatus. Alternatively, oil may be added between them.

Further, in each of the above cases, the method for oiling is not particularly limited. For example, the method may be performed directly on the plant material and the crushed mixture, or may be performed indirectly. You may go on. The oiling performed directly includes various known methods for adhering a liquid such as spray coating, dripping and dipping to a solid. These methods may use only 1 type and may use 2 or more types together. Of these, spray coating is preferred. By spray coating, the oil component can be added to the plant material and / or the crushed mixture with good dispersibility, and a high oil addition effect can be obtained with a small amount of the oil component used while suppressing loss of the oil component. In the case of direct oil addition, an oil content adding device (reference numeral 400 in FIG. 1) or the like can be used. That is, in order to uniformly add the oil content, the storage means for storing the crushed mixture (reference numeral 401 in FIG. 1), the spray means for spraying the oil content (reference numeral 403 in FIG. 1) onto the crushed mixture, and the oil content. An oil adding device equipped with a stirring means (not shown) can be used.
On the other hand, as an oil addition that is performed indirectly, by supplying oil to a cutting blade that cuts vegetable material or a disk die in a roller disk die type pelletizer, the vegetable material or crushed mixture is indirectly added. The case where oil is supplied is mentioned.

  Moreover, the kind of oil component used in this oil addition step is not particularly limited, and mineral oil, synthetic oil, vegetable oil, and the like can be used. Any one of these may be used, and two or more kinds are used in combination. May be. Examples of the mineral oil include paraffinic oil, naphthenic oil, and aromatic oil. Synthetic oils include synthetic polyolefin oils (α-olefin oligomer, hydrogenated α-olefin oligomer, butene oligomer, hydrogenated butene oligomer, amorphous copolymer oligomer of α-olefin and ethylene), synthetic paraffin oil, and the like. (Synthetic isoparaffin, etc.), synthetic ester oil (diester oil (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyol ester oil (trimethylolpropane capri) Rate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate etc.)}, polyoxyalkylene glycol, alkylbenzene, dialkyldi Phenyl ether, polyphenyl ether, alkylnaphthalene, polysiloxanes {silicone oil (polydimethylsiloxane, polymethylphenylsiloxane and dimethylsiloxane - diphenylsiloxane copolymer)} and the like. Furthermore, examples of vegetable oils (including processed vegetable oils) include palm oil, palm oil, corn oil, cotton oil, rapeseed oil, castor oil, soybean oil, olive oil, and processed oils thereof.

Among these, mineral oil and synthetic oil are preferable, and mineral oil is more preferable. Furthermore, paraffinic oil is preferable among the mineral oils. The paraffinic oil is obtained when the ndM ring analysis method {according to ASTM-D3238, paraffin component content (C _P ), naphthene component content (C _N ), aromatic component content (C _A ) , C _P + C _N + C _A = 100 (%)}, the oil has a paraffin component content (C _P ) of 50% or more. The paraffinic oil includes liquid paraffin and paraffin wax, and liquid paraffin is preferable.

The kinematic viscosity of the paraffinic oil is not particularly limited, but is preferably 30 mm ² / S or less (usually 2.0 mm ² / S or more) at 100 ° C. If it is a paraffinic oil in this range, it can be appropriately infiltrated into these by adding to the plant material and / or crushed mixture, and is excellent in pellet properties obtained (easily pelletized, There is almost no disintegration of the resulting pellets). In addition, when oil is added to the plant material and / or the crushed mixture, it can be easily added with good dispersibility.
Further, the flash point of the paraffinic oil is not particularly limited, but is preferably 100 ° C. or higher (usually 250 ° C. or lower). If it is this range, even if it performs another process after adding an oil component, the function of these oil components can fully be maintained. The flash point is more preferably 120 to 200 ° C, and particularly preferably 150 to 200 ° C.

  Further, in the oil addition step, the amount of oil added when the total of the plant material and the thermoplastic resin is 100 parts by mass is 1 to 17 parts by mass in total. That is, when a plurality of oil addition steps are provided, the total amount of oil added in each oil addition step is 1 to 17 parts by mass. Within this range, it is possible to obtain the effect of suppressing the disintegration of pellets due to oil addition, the effect of improving mechanical properties, the effect of improving the pelletization rate, and the like. Even if the oil component is added in excess of 17 parts by mass, the effect of suppressing the collapse of the pellet and improving the impact resistance can be sufficiently obtained. However, the oil component can be obtained from the pelletized thermoplastic composition pellet or a molded product obtained from the pellet. Is not preferable because it tends to bleed out and becomes excessive. 1.0-15 mass parts is preferable, as for the sum total of the addition amount of this oil component, 2.0-12 mass parts is more preferable, and 3.0-10 mass parts is especially preferable.

In this method, in addition to the mixing step, the crushing step, the pellet step, and the oil addition step, other steps can be provided. As another process, the process (plant material pelletization process) of pressing the plant material used before a mixing process and obtaining a plant material pellet as mentioned above is mentioned. In this vegetable material pelletizing step, a roller disk die molding machine 500 can be used as in the pelletizing step of pelletizing the crushed mixture.
When the plant material pelletizing step is provided, the specific gravity of the plant material can be made close to that of the thermoplastic resin, and the specific gravity difference between the plant material and the thermoplastic resin can be reduced. For this reason, the uneven distribution of the material at the time of mixing can be suppressed, and the mixture in which the vegetable material and the thermoplastic resin were disperse | distributed more uniformly mutually can be obtained. And the molded object obtained can obtain more excellent mechanical properties. In addition, by increasing the apparent specific gravity of the plant material, the bulkiness can be reduced, the handleability is improved, and the efficiency in producing the thermoplastic composition pellets is improved, such as easy introduction into a mixing and melting apparatus. .

  In addition, in the manufacturing method of this invention, another component can be mix | blended besides a vegetable material, a thermoplastic resin, and oil. As other components, various antistatic agents, flame retardants, antibacterial agents, colorants, and the like can be blended. These may use only 1 type and may use 2 or more types together. These other components may be blended in any process. However, in the method of the present invention, it is not necessary to use any additive for promoting the mixing of the plant material and the thermoplastic resin.

[2] Method for Producing Molded Product The method for producing a molded product of the present invention is characterized in that a molded product is obtained by injection molding the thermoplastic composition pellets obtained by the above method. That is, the manufacturing method of this molded object is equipped with the shaping | molding process which obtains a molded object by injection-molding a thermoplastic composition pellet.
Since the thermoplastic composition pellets contain a large amount of plant material as described above and are excellent in collapse resistance, the thermoplastic composition pellets accurately measured in the injection cylinder of the injection molding machine can be obtained. The molded product obtained is excellent in formability without causing a lack of thickness or the like. Furthermore, the molded body obtained by the method of the present invention is more excellent in impact resistance than a molded body made of pellets obtained without an oiling step. Furthermore, since the thermoplastic composition pellets obtained by the above method have excellent fluidity, the molding time (such as the metering time in an injection molding machine) at the time of molding and the injection time can be shortened, resulting in a shortened molding cycle. Thus, the molding efficiency can be improved.
In addition, the injection molding machine (reference numeral 600 in FIG. 1), the mold attached thereto (reference numeral 61 in FIG. 1), various molding conditions, and the apparatus to be used in the injection molding of this manufacturing method are not particularly limited. It is preferable to use an appropriate one depending on the molded body and properties, the type of thermoplastic resin used, and the like.

  The shape, size, thickness and the like of the molded body obtained by the production method of the present invention are not particularly limited. Further, its use is not particularly limited. This molded body is used, for example, as an interior material, an exterior material, a structural material, or the like for an automobile, a railway vehicle, a ship, an airplane, or the like. Among these, examples of the automobile article include an automobile interior material, an automobile instrument panel, and an automobile exterior material. Specifically, door base material, package tray, pillar garnish, switch base, quarter panel, armrest core material, automotive door trim, seat structure material, seat backboard, ceiling material, console box, automotive dashboard, various types Instrument panel, deck trim, bumper, spoiler and cowling. Furthermore, for example, interior materials such as buildings and furniture, exterior materials, and structural materials may be mentioned. That is, a door cover material, a door structure material, a cover material of various furniture (desk, chair, shelf, bag, etc.), a structural material, etc. are mentioned. In addition, a package, a container (such as a tray), a protective member, a partition member, and the like can be given.

Hereinafter, the present invention will be specifically described with reference to examples.
[1] Production of thermoplastic composition pellets Plant material which is a kenaf core (Experimental Examples 1-7) having a particle size of 1 mm or less or a kenaf fiber (Experimental Examples 8-9) having a fiber length of 3 mm, and PP (Nippon Polypro Corporation) The material supply chamber (reference numeral in FIG. 3) of the mixing and melting device 1 (equipment shown in WO2004-076044, manufactured by M & F Technology, Inc.) in the quantitative ratio shown in Table 1 with the product name “NBX03HRS”) 13) (total of 700 g of plant material and thermoplastic resin was added in the quantitative ratio of Table 1), and then mixed and kneaded in a mixing chamber (capacity 5 L, symbol 3 in FIG. 3). During this mixing, the mixing blades (reference numeral 10 in FIG. 3 and reference numerals 10a to 10f in FIG. 4) were rotated at a rotational speed of 2000 rpm. Then, the load (torque) applied to the mixing blade increased, reached the maximum value (exceeding 100%), 6 seconds later, the mixing was stopped, and the resulting mixture was discharged from the mixing and melting apparatus.

  The kenaf core was crushed by a crusher (type “Z10-420” manufactured by Horai Co., Ltd.), and the particle size thereof was a round plate sieve having an aperture of 1.0 mm in accordance with JIS Z8801. Is passed. The kenaf fiber is an average value measured for a total of 200 fibers by taking out single fibers one by one at random according to JIS L1015 and measuring the fiber length on a measuring scale.

Each obtained mixture was crushed to about 5.0 mm (size passing through a 5.0 mm mesh) using a crusher (manufactured by Horai Co., Ltd., type “Z10-420”) to obtain a crushed mixture.
Subsequently, paraffinic oil {made by Idemitsu Kosan Co., Ltd., product name “Diana Process Oil PW-90”, C _P (%): C _N (%): C _A (%) = 71: 29: 0, kinematic viscosity (100 ° C.) 11.25 mm ² / S} and the quantitative ratio in Table 1 {the amount of oil added when the entire pulverized mixture (consisting of plant material and PP) is 100 parts by mass} It added to the crushing mixture so that it might become (in Experiment example 1 and 8, oil content addition was not performed).
After that, the oiled crushed mixture was charged into a roller disk die molding machine 500 (manufactured by Kikukawa Iron Works Co., Ltd., model “KP280”, through-hole diameter (reference numeral 511 in FIG. 2) 4.2 mm) at a feeder frequency of 20 Hz. Each crushing mixture was made into a cylindrical pellet having a diameter of about 4 mm and a length of about 5 mm. Then, the obtained pellet was dried at 100 degreeC in oven for 24 hours, and the thermoplastic composition pellet of Experimental example 1-9 was obtained.

[2] Manufacture of molded body Each thermoplastic composition pellet of Experimental Examples 1 to 9 obtained in [1] above was put into an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., type “SE100DU”), A rectangular plate-shaped test piece having a thickness of 4 mm, a width of 10 mm, and a length of 80 mm was obtained by injection molding under conditions of a cylinder temperature of 190 ° C. and a mold temperature of 40 ° C. In addition, 100 test pieces were prepared for each of the thermoplastic composition pellets of each experimental example.

[3] Evaluation of characteristics After the test piece molded in the above [2] was released from the mold, the presence or absence of a thin wall formed in each test piece was visually observed. The lacking part is a part of the molded part that is missing (because the amount of pellets weighed and put into the cylinder of the injection molding machine is small and the amount of the thermoplastic composition is less than the cavity volume of the mold) It is thought to occur). Then, the number of blanks found in each of 100 test pieces was set to 100 minutes, and the blanking rate (%) was also shown in Table 1.

  Further, a bar flow die (having a square spiral cavity having a width of 20 mm and a thickness of 2 mm) was connected to the injection molding machine, a cylinder temperature of 190 ° C., a mold temperature of 40 ° C., an injection pressure of 150 MPa, and an injection speed of 80 mm / second. , Measure the length (flow length) of the molded product obtained by injection molding under the condition of a measurement value 60 (with the screw retracted 60 mm to ensure a molten resin storage area of 60 mm in the cylinder). These are also shown in Table 1 (described in the bar flow column).

  The bending elastic modulus and the amount of deflection were measured using the test pieces of Experimental Examples 1 to 9 obtained in [2] above. Of these, the flexural modulus was supported at two fulcrums (curvature radius 5 mm) with a distance between fulcrums (L) of 64 mm, while the test piece was supported at the center between the fulcrums (curvature radius 5 mm) at a speed of 2 mm. Measurement was performed by applying a load at / min (based on JIS K7171). Moreover, the stroke amount of the said action point when each test piece fractured | ruptured in the said bending test was measured as deflection amount. The results are also shown in Table 1 above.

[4] Effects of Examples From the results of Table 1, it can be seen that the lack of meat ratio can be reliably reduced by adding oil. That is, in Experimental Example 1 in which no oil was added, the missing rate was 15%, whereas in Experimental Example 2 in which 1 part by mass of oil was added, the missing rate was lower than in Experimental Example 1. The reduction was 46%, and the thickness loss rate was reduced to 8%. Furthermore, in Experimental Examples 3 to 6 to which 3 to 15 parts by mass of oil was added, the thinning rate was 0% in all cases, and excellent shapeability in which no thinning was observed in all the test pieces was obtained. . Further, in Experimental Example 7 in which 20 parts by mass of oil was added, although injection molding could be performed without any problem, bleed out of the oil was recognized from the test piece.

  On the other hand, it can be seen that by adding the oil, as shown in each experimental example, the amount of bending is increased, the flexural modulus is appropriately reduced, and the impact resistance is improved. That is, it can be seen that a molded body excellent in practicality can be obtained in which cracking without accumulating excessive stress is achieved. In particular, the effect of increasing the amount of deflection is significant when kenaf fibers are used as the plant material, and the amount of deflection in Experimental Example 8 to which no oil is added is 3.0 mm, whereas it is only 3 masses. The amount of deflection in Experimental Example 9 to which part of the oil was added was 6.2 mm, which was 2.1 times that of Experimental Example 8.

  The method for producing a thermoplastic composition pellet and the method for producing a molded product of the present invention are widely used in the fields related to automobiles and construction. Particularly suitable for interior materials, exterior materials and structural materials for automobiles, railway vehicles, ships and airplanes, etc. Especially as automotive products, suitable for automotive interior materials, automotive instrument panels, automotive exterior materials, etc. It is. Specifically, door base material, package tray, pillar garnish, switch base, quarter panel, armrest core material, automotive door trim, seat structure material, seat backboard, ceiling material, console box, automotive dashboard, various types Instrument panel, deck trim, bumper, spoiler and cowling. Furthermore, it is also suitable for interior materials, exterior materials and structural materials such as buildings and furniture. Specifically, door cover materials, door structure materials, cover materials for various furniture (desks, chairs, shelves, bags, etc.), structural materials, and the like can be given. In addition, it is also suitable as a package, a container (such as a tray), a protective member, and a partition member.

It is explanatory drawing which shows typically each process from the manufacturing method of this thermoplastic composition pellet to the manufacturing method of this molded object. It is a typical perspective view which shows an example of the principal part of a roller disc die type molding machine. It is typical sectional drawing which shows an example of a mixing-melting apparatus. It is a typical side view which shows an example of the mixing blade | wing arrange | positioned by the mixing-melting apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Mixing and melting apparatus, 3; Mixing chamber, 5; Rotating shaft, 10 and 10a-10f; Mixing blade, 12; Spiral blade, 13; Material supply chamber,
300; crusher, 301; crushing mixture,
400; Oil content adding device 401; Storage means 402; Spray means 403; Oil content;
500; roller disk die type molding machine (pelletizing device), 50; roller disk die type molding part (pelletizing part), 51; disk die, 511; through hole, 512; main rotary shaft insertion hole, 52; press roller 521; concavo-convex portion, 53; main rotating shaft, 54; press roller fixing shaft, 55; cutting blade, 56; thermoplastic composition pellet,
600; injection molding machine, 61; mold.

Claims (7)

Production of a thermoplastic composition pellet containing a plant material and a thermoplastic resin, wherein the plant material and the thermoplastic resin are 100% by mass, and the plant material is contained in an amount of 50 to 95% by mass. A method,
A mixing step of mixing with the plant material while melting the thermoplastic resin using a mixing and melting apparatus;
A crushing step of crushing the mixture obtained in the mixing step to obtain a crushing mixture;
A pelletizing step of pressing and solidifying the crushed mixture to obtain pellets,
Further, at least one of an oil addition step for adding oil to the plant material before the mixing step, and an oil addition step for adding oil to the crushed mixture before the crushed mixture becomes the pellets. With an oil addition process,
In the oil component addition step, when the total of the plant material and the thermoplastic resin is 100 parts by mass, the thermoplastic component is added so that the total amount of oil is 1 to 17 parts by mass. Pellet manufacturing method.   The method for producing a thermoplastic composition pellet according to claim 1, wherein the oil is a paraffinic oil.   The pelletizing step uses a roller-type molding machine including a die and a roller that is rotated in contact with the die, presses the crushed mixture into the die by the roller, and then extrudes the pellet from the die. The method for producing a thermoplastic composition pellet according to claim 1 or 2, wherein the thermoplastic composition pellet is a step of forming a thermoplastic resin. The mixing and melting apparatus includes a mixing chamber for performing the mixing and a mixing blade disposed in the mixing chamber,
The thermoplastic composition pellet according to any one of claims 1 to 3, wherein in the mixing step, the thermoplastic resin melted by rotation of the mixing blade in the mixing chamber and the plant material are mixed. Manufacturing method.   The method for producing a thermoplastic composition pellet according to any one of claims 1 to 4, wherein the plant material is kenaf.   The method for producing a thermoplastic composition pellet according to any one of claims 1 to 5, wherein the thermoplastic resin is polypropylene and / or an ethylene / propylene copolymer.   A method for producing a molded body, comprising: molding a thermoplastic composition pellet obtained by the method for producing a thermoplastic composition pellet according to any one of claims 1 to 6 to obtain a molded body.

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