JP2011005783A - Method for producing thermoplastic resin composition and method for producing molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a thermoplastic resin composition which obtains good flowability and is excellent in mechanical characteristics in spite of a large content of a vegetable material and a method for producing a molding using the composition.SOLUTION: The method for producing the composition containing 50-95 mass% of the vegetable material includes a process in which with the use of a first mixing melting apparatus having a mixing tool in which a plurality of mixing blades are erected/installed in the circumferential direction of a rotary shaft, while a thermoplastic resin (A1) not acid-modified is melted, the vegetable material, the resin (A1), and an organic peroxide are mixed to obtain a first composition, and a process in which by using a second mixing melting apparatus having the same mixing tool, while a thermoplastic resin (A2) not acid-modified and an acid-modified thermoplastic resin (B) are melted together, the first composition, the resin (A2), and the resin (B) are mixed to obtain a second composition. Moreover, the molding is obtained by injection-molding the thermoplastic resin composition obtained by the method for producing the thermoplastic resin composition.

Description

  The present invention relates to a method for producing a thermoplastic resin composition and a method for producing a molded body. More specifically, the present invention relates to a method for producing a thermoplastic resin composition 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 quickly and have a large amount of carbon dioxide absorption are attracting attention from the viewpoint of reducing carbon dioxide emissions and fixing carbon dioxide, 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 obtained composite material. This is because it is difficult to impart sufficient fluidity equivalent to that of conventional resins to the composite material.
Regarding this problem, the following Patent Documents 1 to 3 disclose techniques for improving fluidity using an organic peroxide when mixing a plant material and a resin.

Japanese Patent Laid-Open No. 55-133101 JP-A 61-155436 JP 2007-169612 A

  Patent Document 1 and Patent Document 2 include a resin composition containing a propylene resin, a modified propylene resin such as an unsaturated carboxylic acid modification, a plant material such as wood flour or vegetable fiber, and an organic peroxide. Is disclosed. In these resin compositions, the mechanical properties and the fluidity are made to be compatible by using a modified propylene resin and an organic peroxide in combination. However, in any of the above-mentioned documents, the method for producing these resin compositions does not consider the mixing of the components contained in the resin composition, and the modified propylene resin and the organic peroxide are simultaneously used. Only a production method of mixing is shown. Patent Document 3 discloses a resin composition containing a propylene-based resin, a modified propylene-based resin, and a wood-based material, and mentions the combined use of an organic peroxide. However, in the method for producing the resin composition, no consideration is given to mixing of the components.

  The present invention has been made in view of the above, and has excellent fluidity capable of performing injection molding while containing a large amount of plant material as 50 to 95% by mass, and has excellent mechanical properties. It aims at providing the manufacturing method of a plastic resin composition, and the manufacturing method of a molded object using the same.

That is, the present invention is as follows.
(1) A method for producing a thermoplastic resin composition comprising a plant material and a thermoplastic resin, wherein the plant material is 50 to 95% by mass when the total of these is 100% by mass,
Using a first mixing and melting apparatus including a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotation shaft, a thermoplastic resin (A1) that is not acid-modified by shearing force generated by the rotation of the mixing blades A first mixing step of mixing the vegetable material, the non-acid-modified thermoplastic resin (A1), and the organic peroxide to obtain a first composition,
Using a second mixing and melting apparatus provided with a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotating shaft, a thermoplastic resin (A2) that is not acid-modified by the shearing force generated by the rotation of the mixing blades ) And the acid-modified thermoplastic resin (B) are melted together, and the first composition is mixed with the acid-free thermoplastic resin (A2) and the acid-modified thermoplastic resin (B). And a second mixing step for obtaining a second composition, and a method for producing a thermoplastic resin composition.
(2) In the first mixing step, when the total of the plant material and the non-acid-modified thermoplastic resin (A1) is 100 parts by mass, the organic peroxide is 0.01 to 0. The manufacturing method of the thermoplastic resin composition as described in said (1) which is 0.5 mass part.
(3) The total of the non-acid-modified thermoplastic resin (A1) used in the first mixing step and the non-acid-modified thermoplastic resin (A2) used in the second mixing step is 100 mass. % Of the thermoplastic resin composition (A1) used in the first mixing step is 20 to 50% by mass of the thermoplastic resin composition according to (1) or (2). Production method.
(4) In the first mixing step, when the total of the plant material and the non-acid-modified thermoplastic resin (A1) is 100% by mass, the plant material is 70 to 98% by mass. The manufacturing method of the thermoplastic resin composition in any one of said (1) thru | or (3).
(5) The non-acid-modified thermoplastic resin (A1) used in the first mixing step, the non-acid-modified thermoplastic resin (A2) used in the second mixing step, and the acid-modified thermoplastic. When the total of the resin (B) is 100% by mass, the acid-modified thermoplastic resin (B) is 1 to 30% by mass in any one of (1) to (4) The manufacturing method of the thermoplastic resin composition of description.
(6) The said vegetable material is a manufacturing method of the thermoplastic resin composition in any one of said (1) thru | or (5) which is kenaf.
(7) The heat according to any one of (1) to (6), further including a pelletizing step in which the crushed material obtained by crushing the second composition is pressed and pelletized without heating. A method for producing a plastic resin composition.
(8) A molded article is obtained by injection molding a thermoplastic resin composition obtained by the method for producing a thermoplastic resin composition according to any one of (1) to (7). Manufacturing method of a molded object.

According to the method for producing a thermoplastic resin composition of the present invention, excellent fluidity capable of performing injection molding is obtained while containing a large amount of plant material at 50 to 95% by mass and also excellent in mechanical properties. A thermoplastic resin composition can be obtained. That is, only a part of the thermoplastic resin that is not acid-modified among the thermoplastic resins to be used is mixed with the plant material and the organic peroxide in advance, and then the other components are added and mixed to thereby modify the acid. The resulting thermoplastic resin composition has both excellent fluidity and mechanical properties while suppressing the decrease in the molecular weight of the unmodified thermoplastic resin and without inhibiting the additive effect of the acid-modified thermoplastic resin. Is done.
When the total amount of the plant material and the non-acid-modified thermoplastic resin (A1) in the first mixing step is 100 parts by mass, the organic peroxide is 0.01 to 0.5 parts by mass. Can achieve both excellent fluidity and excellent mechanical properties.
When the total of the non-acid-modified thermoplastic resin (A1) used in the first mixing step and the non-acid-modified thermoplastic resin (A2) used in the second mixing step is 100% by mass, When the plastic resin (A1) is 20 to 50% by mass, it is possible to achieve both excellent fluidity and excellent mechanical properties.
When the total of the plant material and the non-acid-modified thermoplastic resin (A1) in the first mixing step is 100% by mass, the plant material is 70 to 98% by mass. In addition, it is possible to achieve both excellent fluidity and excellent mechanical properties.
The non-acid-modified thermoplastic resin (A1) used in the first mixing step, and the non-acid-modified thermoplastic resin (A2) and the acid-modified thermoplastic resin (B) used in the second mixing step. When the total is 100% by mass, particularly excellent mechanical properties can be obtained when the acid-modified thermoplastic resin (B) is 1 to 30% by mass.
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.
Furthermore, in the case of providing a pelletizing step in which a crushed product obtained by crushing the second composition is pressed and pelletized without heating, thermal deterioration is suppressed by reducing the thermal history, and excellent fluidity and A thermoplastic resin composition having both excellent mechanical properties can be obtained in the form of pellets while maintaining the properties.
According to the method for producing a molded article of the present invention, a molded article having excellent injection moldability and excellent mechanical properties can be obtained while containing a large amount of plant material at 50 to 95% by mass.

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. It is a typical perspective view which shows an example of the principal part of a roller disc die type molding machine. It is a top view which shows the shape of the metal mold | die used for the measurement of bar flow length, and a cavity.

Hereinafter, the present invention will be described in detail.
[1] Method for Producing Thermoplastic Resin Composition The method for producing a thermoplastic resin composition of the present invention comprises a plant material and a thermoplastic resin. It is a manufacturing method of the thermoplastic resin composition whose material is 50-95 mass%, Comprising: The following 1st mixing process and the following 2nd mixing process are provided, It is characterized by the above-mentioned.

(1) 1st mixing process The said 1st mixing process is rotation of a mixing blade using the 1st mixing and melting apparatus provided with the mixing tool by which the several mixing blade was installed in the circumferential direction of the rotating shaft. The first composition is prepared by mixing the plant material, the non-acid-modified thermoplastic resin (A1), and the organic peroxide while melting the non-acid-modified thermoplastic resin (A1) by the shearing force of the first composition. It is the process of obtaining.

The “plant material” is a plant-derived material. 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.

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, heba, cubane kenaf, western hemp, taikenaf, mesta, bimli, ambari, and bombay are known as common names.
The jute in the present invention is a fiber obtained from jute hemp. This jute hemp includes hemp and linden plants including jute (Corchus capsularis L.), and leopard (Tunaso), Shimatsunaso and Morohaya.

The shape of the plant material {plant material before mixing} is not particularly limited, and may be fibrous or non-fibrous. A fibrous plant material (hereinafter, also simply referred to as “vegetable fiber”) is a fiber taken out from a plant body, and has a maximum length (fiber length) L and a minimum length (fiber diameter) perpendicular to L. ) The ratio L / t of t is 5.0 or more. As the vegetable fiber, kenaf fiber is particularly preferable. On the other hand, non-fibrous plant materials (hereinafter also simply referred to as “non-fibrous plant materials”) include powders (including granules and spheres), chips (including plates and flakes). And forms such as indefinite shapes (including crushed materials). This non-fibrous plant material has an average value of L / t of less than 5.0. This non-fibrous plant material is preferably kenaf core powder.
The maximum length L is a value measured by stretching one plant material straight without stretching, as in the direct method in JIS L1015. On the other hand, the minimum length t is a value obtained by measuring the minimum length orthogonal to the L of the plant material.

  Only one of the plant fiber and the non-fibrous plant material may be used or used in combination, but among these, plant fiber is preferable. By using vegetable fiber, more excellent fluidity and mechanical properties can be obtained. The average value of L / t (average value measured by randomly extracting 200 plant materials) of the plant material used in the present invention is preferably 5.0 or more, and preferably from 5.0 to 20,000 is more preferable.

Moreover, when using vegetable fiber, the average fiber length, average fiber diameter, etc. are not specifically limited, However, The average fiber length is preferably 0.5 to 100 mm, more preferably 0.7 to 30 mm, and particularly preferably 1 to 10 mm. preferable. On the other hand, the average fiber diameter is preferably 0.01 to 1 mm, more preferably 0.01 to 0.15 mm, and particularly preferably 0.01 to 0.1 mm.
In the thermoplastic resin composition 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 contained in the thermoplastic resin composition.

  The “acid-modified thermoplastic resin (A1)” (hereinafter also simply referred to as “resin A1”) is a thermoplastic resin used in the first mixing step, and is a resin that is not acid-modified. The resin A1 is not particularly limited and various resins can be used. For example, polyolefin, polyester, polystyrene, acrylic resin (resin using methacrylate and / or acrylate), polyamide, polycarbonate, polyacetal, and ABS resin etc. are mentioned. Among these, polyolefins include isotactic propylene homopolymer (hereinafter referred to as “PP homopolymer”), ethylene-propylene block copolymer resin (hereinafter referred to as “EP block copolymer resin”), polyethylene, and the like. Can be mentioned. Examples of the polyester include aliphatic polyesters such as polylactic acid, polycaprolactone, and polybutylene succinate, and aromatic polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate. Among these, polyolefin is preferable. Resin A1 may use only 1 type in the above, and may use 2 or more types together.

  The “organic peroxide” is an organic compound having —O—O— bond in the molecule. By blending this organic peroxide only in the first mixing step and not coexisting with the acid-modified thermoplastic resin, only a part of the non-acid-modified thermoplastic resin is used in the first mixing step. The flow rate and mechanical properties of the thermoplastic resin composition obtained are excellent in suppressing the molecular weight reduction of the non-acid-modified thermoplastic resin and without inhibiting the effect of addition of the acid-modified thermoplastic resin. Can be achieved.

  These organic peroxides include dialkyl peroxide organic peroxides, peroxyketal organic peroxides, alkyl perester organic peroxides, ketone peroxide organic peroxides, diacyl peroxide organic peroxides. Examples thereof include oxides, hydroperoxide-based organic peroxides, and peroxycarbonate-based organic peroxides. These may use only 1 type and may use 2 or more types together. Of these, dialkyl peroxide organic peroxides are preferred.

  The dialkyl peroxide organic peroxide is an organic peroxide having a structure in which two hydrogen atoms of hydrogen peroxide are substituted with an alkyl group or an aralkyl group. Examples of the dialkyl peroxide organic peroxide include bis [(t-butylperoxy) isopropyl] benzene, di-t-butyl peroxide, t-butyl-α-cumyl peroxide, di-α-cumyl peroxide, Examples include 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) -3-hexyne and the like. These may use only 1 type and may use 2 or more types together. Of these, bis [(t-butylperoxy) isopropyl] benzene is preferred.

  In the first mixing step, the acid-modified thermoplastic resin (B) is not used. Similarly, no organic peroxide is used in the second mixing step. This is because, when an acid-modified thermoplastic resin (B) and an organic peroxide are mixed, the acid-modified thermoplastic resin (B) is decomposed by the organic peroxide, and the thermoplastic resin by the resin (B). This is because it is difficult to sufficiently obtain the additive effect of improving the mechanical properties by improving the bondability between the potato and the plant material.

Although the compounding quantity of the component used in a 1st mixing process, ie, vegetable material, resin (A1), and an organic peroxide is not specifically limited, The sum total of vegetable material and resin (A1) was 100 mass%. In this case, the plant material is preferably 70 to 98% by mass. In this range, the first mixing and melting apparatus is used, and by using an organic peroxide, a large amount of plant material is taken into a small amount of the resin (A1), and sufficient fluidity is ensured and mixed. it can. This amount is more preferably 70 to 90% by mass, and particularly preferably 75 to 85% by mass.
Moreover, although a part of plant material can also be mix | blended in the 2nd mixing process mentioned later, it is preferable to mix | blend the whole quantity in a 1st mixing process.

  Furthermore, when the sum total of plant material and resin (A1) in a 1st mixing process is 100 mass parts, it is preferable that the said organic peroxide shall be 0.01-0.5 mass part. Within this range, it is possible to obtain a thermoplastic resin composition in which better fluidity and better mechanical properties are compatible. This is considered to be due to the fact that the decomposition of the plant material is appropriately advanced by the appropriate blending of the organic peroxide. This amount is more preferably 0.03 to 0.4 parts by mass, and particularly preferably 0.05 to 0.3 parts by mass.

  Moreover, it is preferable that resin A1 is 20-50 mass% when the sum total of resin A1 used at a 1st mixing process and resin A2 used at the 2nd mixing process mentioned later is 100 mass%. In this range, a thermoplastic resin composition having more excellent fluidity and mechanical properties can be obtained. The resin A1 is more preferably 25 to 50% by mass, still more preferably 30 to 50% by mass, and particularly preferably 30 to 45% by mass.

The “first composition” is a composition obtained by the first mixing step, and includes a plant material, a resin (A1), and a decomposition product of an organic peroxide. Although the bar flow length of this 1st composition is not specifically limited, It is preferable that it is 50-180 mm. By setting the fluidity of the first composition to the bar flow length in the above range, the fluidity and mechanical properties of the resulting thermoplastic resin composition can be more suitably achieved. The bar flow length is more preferably 60 to 180 mm, and still more preferably 70 to 180 mm.
The bar flow length is determined by connecting a bar flow mold (a mold having an angular spiral cavity with an inlet diameter of 10 mm, a width of 20 mm and a thickness of 2 mm) to an injection molding machine, a cylinder temperature of 190 ° C., and a mold temperature of 40 Of a molded body obtained by injection molding under the conditions of ℃, injection pressure 150 MPa, injection speed 80 mm / second, and weighing value 60 (retracting the screw 60 mm to secure a storage area for 60 mm of the injection object in the cylinder) Length.
The first mixing and melting apparatus will be described later together with the second mixing and melting apparatus.

(2) Second Mixing Step The “second mixing step” is the rotation of the mixing blade using a second mixing and melting apparatus provided with a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotation shaft. The first composition and the non-acid-modified thermoplastic resin (A2) and the acid-modified thermoplastic resin (A2) and the acid-modified thermoplastic resin (B) are melted together by the shearing force of This is a step of mixing the acid-modified thermoplastic resin (B) to obtain a second composition.

The “acid-modified thermoplastic resin (A2)” (hereinafter also simply referred to as “resin A2”) is a thermoplastic resin used in the second mixing step, and is a resin that is not acid-modified. As this resin A2, the same thermoplastic resin as the resin A1 used in the first mixing step can be used, and among them, polyolefin is preferable. Further, the molecular weight of the resin A2 is not particularly limited, but a preferable weight average molecular weight in the resin A1 can be applied as it is.
The resin A1 and the resin A2 may be different types of resins, but are preferably the same resin. That is, both the resin A1 and the resin A2 are preferably polyolefin.

  The “acid-modified thermoplastic resin (B)” (hereinafter also simply referred to as “resin B”) is a thermoplastic resin into which an acid group has been introduced. Although the kind of this acid group is not specifically limited, Usually, they are a carboxylic anhydride residue (-CO-O-OC-) and / or a carboxylic acid residue (-COOH). The acid group may be introduced by any compound, but as the compound for introducing an acid group, acid anhydrides such as maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, and adipic anhydride, and Examples thereof include carboxylic acids such as maleic acid, itaconic acid, fumaric acid, acrylic acid, and methacrylic acid. These may be used alone or in combination of two or more. Of these compounds, acid anhydrides are preferred, maleic anhydride and itaconic anhydride are more preferred, and maleic anhydride is particularly preferred.

Furthermore, the kind of the thermoplastic resin (hereinafter referred to as “skeleton resin”) serving as a skeleton constituting the resin B is not particularly limited, and various thermoplastic resins can be used. Examples of the skeleton resin include various resins exemplified as the resin A1 and the resin A2, and among them, polyolefin is preferable.
The skeleton resin of the resin B, the resin A1 and the resin A2 may be the same type of resin or different resins, but are preferably the same type, and more preferably are all polyolefins. Polyolefin is easy to handle and has excellent flexibility and formability. As this polyolefin, PP homopolymer, EP block copolymer resin, polyethylene and the like are preferable (skeleton resin in the resin B). Further, it is more preferable that the skeleton resin of the resin B, the resin A1 and the resin A2 are both PP homopolymer and / or EP block copolymer resin, and further, the resin B is modified with maleic anhydride. The PP homopolymer and / or the EP block copolymer resin, and the resin A1 and the resin A2 are particularly preferably a PP homopolymer and / or an EP block copolymer resin.

  Specific examples of this resin B include a product name “Modic” (particularly “Modic-AP P908”, etc.) manufactured by Mitsubishi Chemical Corporation, a product name “Yumex” (particularly “YUMEX” manufactured by Sanyo Chemical Industries, Ltd.). 1001 "and" Yumex 1010 "are preferred), Mitsui Chemicals, Inc., trade name" Admer "(especially" Admer QE800 "is preferred), and Toyo Kasei Kogyo Co., Ltd., trade name" Toyotac ". (In particular, “Toyotack H-1100P-P” and the like are preferable.).

  The amount of the acid group introduced into the resin B is not particularly limited, but when the acid value is used as an index, the acid value may be 5 or more (usually 80 or less), and the acid value is preferably 15 or more. That is, it is preferable that the resin B has a relatively high acid value. With such a resin B, the mechanical properties of the thermoplastic resin composition can be sufficiently improved while suppressing the content of the resin B. The acid value is preferably 15 to 70, more preferably 20 to 60, and even more preferably 23 to 30. This acid value can be measured according to JIS K0070.

  Further, the molecular weight of the resin B is not particularly limited, but the weight average molecular weight is preferably 10,000 to 200,000, particularly preferably 10,000 to 100,000. That is, a resin having a relatively small molecular weight is preferable. By using such a resin B, the mechanical properties of the thermoplastic resin composition can be sufficiently improved while suppressing the amount of the resin B used. The lower limit value of the weight average molecular weight is particularly preferably 15000, particularly 25000, and more preferably 35000, and the upper limit value of the weight average molecular weight is particularly preferably 200000, particularly 150,000, more preferably 100,000. The weight average molecular weight of the resin B is more preferably 35,000 to 60,000. The weight average molecular weight is measured by GPC method (standard polystyrene conversion).

  Further, the melt viscosity of the resin B is not particularly limited, but is preferably 4000 to 30000 mPa · s at 160 ° C. By using such resin B, the mechanical properties of the thermoplastic resin composition can be sufficiently improved while suppressing the content of resin B. The melt viscosity is preferably 4000 to 25000 mPa · s, more preferably 5000 to 20000 mPa · s, and even more preferably 10,000 to 20000 mPa · s. The melt viscosity is measured at 160 ° C. with a B-type viscometer (using No. 4 rotor based on JIS K7117).

  The ratio of the resin B used in the second mixing step is not particularly limited, but when the total of the resin A1, the resin A2, and the resin B is 100% by mass, the amount that the resin B becomes 0.5 to 30% by mass. Is preferably blended. In this range, the mechanical properties of the thermoplastic resin composition can be further improved while suppressing the blending amount of the resin B. 0.5-20 mass% of this resin B is more preferable, 1-10 mass% is still more preferable, and 1-5 mass% is especially preferable.

  The “second composition” is a composition obtained by the second mixing step, and is a thermoplastic resin composition according to the present method. Although this 2nd composition can be used as a thermoplastic resin composition as it is, other processes, such as pelletizing, can be imposed so that it may mention later. These steps will be described later.

(3) Mixing and melting apparatus The "first mixing and melting apparatus" and the "second mixing and melting apparatus" are simply referred to as "mixing and melting apparatus" when the first mixing and melting apparatus and the second mixing and melting apparatus are collectively referred to. ), A device provided with a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotating shaft. While the thermoplastic resin is melted by the shearing force generated by the rotation of the mixing blade of the mixing and melting apparatus, the thermoplastic resin and other components are mixed and mixed (in the first mixing step, in the first composition, in the second mixing step). Is an apparatus capable of obtaining a thermoplastic resin composition). The first mixing and melting apparatus and the second mixing and melting apparatus may be the same or different.
This mixing and melting apparatus usually includes a mixing chamber for performing the above-described mixing. The mixing tool has at least a mixing blade disposed in the mixing chamber. As such a mixing and melting apparatus, the following mixing and melting apparatus is particularly preferable.

  This mixing and melting apparatus (hereinafter, FIG. 1 (FIG. 1 is cited from the pamphlet of International Publication No. 04/076044 obtained from the Patent Electronic Library of the JPO) and FIG. 2 (FIG. 2 is from the Patent Electronic Library of the JPO. As for the acquired International Publication No. 04/076044, FIG. 2), the mixing and melting apparatus 1 described in the International Publication No. 04/076044 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. That is, the mixing and melting apparatus 1 is an apparatus including a mixing tool in which a plurality of mixing blades 10 a to 10 f are erected in the circumferential direction of the rotating shaft 5.

  In the mixing and melting apparatus 1, the mixed material (material to be mixed) is put into the mixing and melting apparatus 1 (material supply chamber 13), and the mixing blades 10 a to 10 f of the mixing and melting device 1 are rotated, so that the mixing blade The generated shear force, the thermoplastic resin and other components are struck and pushed so as to press against the inner wall of the mixing chamber 3, and the thermoplastic resin is softened in a short time by the energy (heat amount) that the materials collide, Furthermore, it is melted, mixed with other components, and further kneaded. And the excellent fluidity | liquidity which can be injection-molded is expressed in the thermoplastic resin composition (2nd composition) obtained after a 2nd mixing process.

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.
The mixing chamber 3 is more preferably provided with a mixing chamber cooling means that can circulate a cooling medium through the walls constituting the mixing chamber 3. With this configuration, an excessive temperature rise in the mixing chamber 3 can be suppressed, and decomposition and thermal deterioration of components such as a thermoplastic resin can be suppressed (and further prevented).

  Moreover, the mixing conditions in each process of the said 1st mixing process and the said 2nd mixing process are not specifically limited. In each mixing step, the load generated on the rotary shaft 5 gradually increases when mixing is started, and then the load gradually decreases through the maximum value of the load. In this method, it is preferable to adjust the mixing state by changing the length of the mixing time that continues after the maximum value of the load.

The mixing time that continues after the maximum load value (torque peak) has passed is preferably 5 seconds or more (usually 125 seconds or less) in the first mixing step, more preferably 10 to 120 seconds. It is more preferable to set it as 15 to 60 seconds, and it is especially preferable to set it as 20 to 40 seconds.
This mixing time is particularly suitable when the diameter of the mixing blade is 20-30 cm. Furthermore, the rotational speed of the rotating shaft 5 (especially the rotational speed until the maximum value of the load is reached) is preferably 1400 to 2200 rpm, more preferably 1500 to 2000 rpm, and particularly preferably 1600 to 1900 rpm. In the first mixing step, when the rotational speed of the rotating shaft until reaching the maximum value of the load is R1, and the rotational speed R2 of the rotating shaft after reaching the maximum value of the load, R2 is relative to R1. The R2 / R1 is more preferably 0.5 to 0.9, and still more preferably 0.6 to 0.8. That is, it is particularly preferable that the mixing is continuously performed by reducing the rotational speed of the rotating shaft after reaching the maximum load value.

  On the other hand, the mixing time continued after passing the maximum value of the load is preferably 20 seconds or less (usually 1 second or more) in the second mixing step, more preferably 1 to 15 seconds, 10 seconds is particularly preferable. This mixing time is particularly suitable when the diameter of the mixing blade is 20-30 cm. Furthermore, the rotational speed of the rotating shaft (especially the rotational speed until reaching the maximum load value) is preferably 1400 to 2200 rpm, more preferably 1500 to 2000 rpm, and particularly preferably 1600 to 1900 rpm. In the second mixing step, R2 is equal to R1 when the rotational speed of the rotary shaft until reaching the maximum value of the load is R1, and the rotational speed R2 of the rotary shaft after reaching the maximum value of the load. R2 / R1 is more preferably 0.8 to 1.2, and still more preferably 0.9 to 1.1.

In addition, the measurement of the said load can be performed by providing the load measurement means which measures the load which arises in a rotating shaft. This load measuring means can be attached to the mixing and melting apparatus itself so that the load generated on the rotating shaft can be directly measured. Furthermore, even if the load on the rotary shaft is indirectly measured by attaching load measuring means to a drive source (motor or the like) usually provided for driving the rotary shaft and measuring the load on the drive source. Good.
Specifically, as illustrated in FIG. 1, a drive source (motor or the like) 8 for rotating the rotating shaft 5 is attached, and the drive source 8 is in rotation communication via the pulley 6 and the V belt 7. It is preferable that The drive source 8 is preferably provided with load measuring means 21. Furthermore, the load measuring means 21 is preferably electrically connected to the drive source 8 and capable of measuring a load (torque) acting on the main shaft of the drive source 8.

(4) Pelletizing step In the method for producing a thermoplastic resin composition of the present invention, in addition to the first mixing step and the second mixing step, a crushed product obtained by crushing the second composition is further heated. There can be provided a pelletizing step in which the mixture is pressed and pelletized. By including this pelletizing step, the thermoplastic resin composition (second composition) can be shaped into a pellet shape, and can be made into a form more suitable for injection molding.

The method for crushing the second composition 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 second composition by moisture absorption and water absorption.
The crusher 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 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.

The size of the crushed material is not particularly limited as long as it can be used for each of the pelletizing steps described later, but the maximum side length is preferably 25 mm or less (usually 1 mm or more), more preferably 1 to 20 mm. -15 mm is more preferable, and 2-7 mm is particularly preferable. If it is this range, it is excellent in the pellet productivity in the subsequent pelletization process, and also in the obtained molded body, the reinforcing effect by the plant material can be obtained particularly well.
In addition, when it grind | pulverizes until it becomes a powder form with a grinder instead of a crusher, it will become difficult to fully extract the reinforcement effect by containing a plant material. For this reason, it is preferable to crush to the appropriate size.
Furthermore, in crushing, it is preferable to suppress an increase in temperature due to crushing, and it is particularly preferable that the temperature of the crushed material during crushing is 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.

Furthermore, it is preferable to pelletize the crushed material obtained by pressing it without heating. Compared to the case where the crushed material is melted and pelletized using a general method such as a twin-screw extruder, the mechanical properties of the molded product obtained can be reduced because the thermal history of the crushed material can be reduced. Can be maintained higher.
Any device and means may be used as a method of pressing and hardening without heating, but various compression molding methods are particularly preferred. Examples of the compression molding method include a roller molding method and an extruder molding method.

The roller type molding method uses a roller type molding machine equipped with a die and a roller that rotates in contact with the die, presses the object to be compressed into the die with the roller, and then extrudes the die to form a pellet. It is. 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, in which a material to be compressed is pressed into a die by rotation of a screw auger and then extruded from the die to form pellets.
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 using a roller disk die molding machine (pelletizing apparatus) having the following specific roller disk die molding section 50 (see FIG. 3). The roller disk die type molding unit 50 includes a disk die 51 having a plurality of through holes 511, a press roller 52 that rolls on the disk die 51 and pushes a material to be compressed into the through holes 511, A main rotating shaft 53 for driving the press roller 52, and the disk die 51 has a main rotating shaft insertion hole 512 that is penetrated in the same direction as the through hole 511. The press roller fixing shaft 54 is inserted through the main rotation shaft 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. As the main rotating shaft 53 rotates, the surface of the disk die 51 rolls.
In addition to the above configuration, the roller disk die-type molding unit 50 preferably further includes irregularities 521 on the surface of the press roller 52. 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 above roller disk die type molding machine, for example, in FIG. 3, the surface unevenness 521 provided in the press roller 52 catches the object to be compressed introduced from above the main rotating shaft 53 and pushes it into the through hole 511, and the disk die Extruded from the back side of 51. The extruded string-like second composition is cut into an appropriate length by the cutting blade 55, pelletized, dropped downward, and recovered as a pellet-shaped thermoplastic resin composition.
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.

  In addition, in the manufacturing method of this invention, other components can be mix | blended besides a vegetable material and a thermoplastic resin. 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 resin composition obtained by the above method. That is, the manufacturing method of this molded object is equipped with the shaping | molding process of injection-molding a thermoplastic resin composition and obtaining a molded object.
The injection molding machine in the injection molding of this production method, the mold attached thereto, various molding conditions and the apparatus to be used are not particularly limited, and the target molded body and properties, the type of thermoplastic resin used It is preferable to make it appropriate according to the above.

  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 of 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 resin composition [1] Example 1
(1) 1st mixing process Average fiber length 2mm as a plant material (Based on JISL1015, the single fiber is taken out one by one at random by a direct method, and fiber length is measured on a measuring scale, and a total of 200 480 g of kenaf fiber (average value measured for the book), 120 g of PP (ethylene / propylene copolymer, manufactured by Nippon Polypro Co., Ltd., product name “Novatech NBC03HR”) as resin A1, and organic peroxide (Kayaku Akzo Corporation) Product name “Parkadox 14/40”) 0.6 g, and a material supply chamber of the first mixing and melting apparatus 1 (M & F Technology Co., Ltd., equipment shown in WO2004-076044) (reference numeral in FIG. 1) 13), mixed and kneaded in a mixing chamber (capacity 5L, symbol 3 in FIG. 1).
At the time of mixing, the rotational speed of the rotating shaft is set to 1750 rpm, mixing is performed for 50 to 60 seconds until the load applied to the rotating shaft reaches the maximum value, and the rotational speed of the rotating shaft is set to 1200 rpm when the load reaches the maximum value. The mixture was further mixed for 30 seconds to form a first composition (after reaching the maximum load value, mixing was performed for 30 seconds and the first composition was discharged from the mixing and melting apparatus).

(2) Second mixing step 450 g of the first composition, 135 g of PP (ethylene / propylene copolymer, manufactured by Nippon Polypropylene Co., Ltd., product name “Novatech NBC03HR”) as the resin A2, and acid-modified PP (Mitsubishi) as the resin B Chemical Co., Ltd., product name “Modic P908”) 15 g, and the material of the second mixing and melting apparatus 1 (M & F Technology Co., Ltd., the apparatus shown in WO 2004-076044, the same as the first mixing and melting apparatus) The mixture was introduced into the supply chamber (reference numeral 13 in FIG. 1), mixed and kneaded in the mixing chamber (capacity 5L, reference numeral 3 in FIG. 1).
During mixing, the rotational speed of the rotating shaft is set to 1750 rpm, mixing is performed for 50 to 60 seconds until the load on the rotating shaft reaches the maximum value, and mixing is performed at the same rotational speed after reaching the maximum value of the load. The second composition was formed continuously for 4 seconds (after reaching the maximum load value, mixing was continued for 4 seconds and the second composition was discharged from the mixing and melting apparatus).

(3) Pelletizing step The second composition obtained up to (2) is passed through a 5.0 mm mesh (5.0 mm mesh) using a crusher (manufactured by Horai Co., Ltd., model “Z10-250”). Size) was obtained. Next, the crushed material is formed into a roller disk die type molding machine {manufactured by Kikukawa Iron Works Co., Ltd., type “KP280”, through-hole diameter (reference numeral 511 in FIG. 3) 4.2 mm} provided with a roller disk die type molding unit 50. A feeder frequency of 20 Hz was added to form a cylindrical pellet having a diameter of about 4 mm and a length of about 5 mm. Thereafter, the obtained pellets were dried in an oven at 100 ° C. for 24 hours to obtain each thermoplastic resin composition of Example 1.

[2] Comparative Example 1
(1) 1st mixing process Except not using an organic peroxide, it carried out similarly to the 1st mixing process in the said [1] Example 1, and obtained the 1st mixture.
(2) Second mixing step [2] A second mixture was obtained in the same manner as the second mixing step in Example 1, except that the first composition obtained in (1) was used. .
(3) Pelletizing step Each thermoplastic resin of Comparative Example 1 is the same as the pelletizing step in [1] Example 1 except that the second composition obtained in [2] (2) is used. A composition was obtained.

[3] Comparative example 2
(1) Mixing step Although each component was used so that it might become the same as the said Example 1, the operation which mixed all the components was performed at once. That is, 360 g of kenaf fiber, 225 g of PP (ethylene-propylene copolymer, manufactured by Nippon Polypro Co., Ltd., product name “Novatech NBC03HR”), and organic peroxide (manufactured by Kayaku Akzo Co., Ltd., product name “Perkadox 14/40”) ] 0.45 g and acid-modified PP (Mitsubishi Chemical Co., Ltd., product name “Modic P908”) 15 g of mixing and melting apparatus 1 (M & F Technology Co., Ltd., equipment shown in WO 2004-076044) The material was supplied into the material supply chamber (reference numeral 13 in FIG. 1), mixed and kneaded in the mixing chamber (capacity 5L, reference numeral 3 in FIG. 1).
During mixing, the rotational speed of the rotating shaft is set to 1750 rpm, mixing is performed for 60 seconds until the load on the rotating shaft reaches a maximum value, and the rotational speed of the rotating shaft is set to 1200 rpm when the maximum load value is reached. The mixture was further mixed for 30 seconds to form a composition (after reaching the maximum load value, mixing was performed for 30 seconds and the composition was discharged from the mixing and melting apparatus).
(2) Pelletizing step The thermoplastic resin composition of Comparative Example 2 was used in the same manner as the pelletizing step in [1] Example 1 except that the composition obtained in [3] (1) was used. Obtained.

<2> Manufacture of molded body Each thermoplastic resin composition of Example 1 and Comparative Examples 1 and 2 obtained in <1> above is used as an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., model “SE100DU”). Each was charged and injection molded under conditions of a cylinder temperature of 190 ° C. and a mold temperature of 40 ° C. to obtain a rectangular plate-shaped test piece having a thickness of 4 mm, a width of 10 mm, and a length of 110 mm.

<3> Evaluation of characteristics The bending strength and the bending elastic modulus were measured based on JIS 7171 using the test piece obtained in the above <2>. In this test, each test piece was supported at two fulcrums (curvature radius 5 mm) with a fulcrum distance (L) of 64 mm, and at a speed of 2 mm / min from an action point (curvature radius 5 mm) arranged at the center between the fulcrums. A load was applied. The results are shown in Table 1.
Further, a bar flow mold (a mold 61 having a square spiral cavity 612 having an inlet 611 diameter of 10 mm and a width of 20 mm and a thickness of 2 mm shown in FIG. 4) is connected to the injection molding machine. Injection under conditions of cylinder temperature 190 ° C, mold temperature 40 ° C, injection pressure 150MPa, injection speed 80mm / sec, weighing value 60 (retract the screw 60mm, and secure a storage area for 60mm in the cylinder) The length of the molded body obtained by molding was measured as the bar flow length. The results are also shown in Table 1.

<4> Effects of Example From the results of Comparative Example 1, when two-stage mixing was performed without using an organic peroxide, a molded body having a bending strength of 72.4 PMa and a bending elastic modulus of 5095 MPa was obtained. Although obtained, it can be seen that the bar flow length is as short as 180 mm. On the other hand, from the results of Comparative Example 2, when all components were mixed together using an organic peroxide, the bar flow length was as long as 210 mm, that is, the fluidity was about 17% better than Comparative Example 1. It turns out that a thermoplastic resin composition is obtained. However, the molded body obtained using the thermoplastic resin composition of Comparative Example 2 has a bending strength of 54.4 PMa and a bending elastic modulus of 4957 MPa, which is approximately the same as that of Comparative Example 1. It can be seen that it has decreased by 25%.

In contrast, in Example 1, the organic peroxide is used in the first mixing step, and the resin B (acid-modified thermoplastic resin) is used in the second mixing step. It can be seen that both of the flow lengths are excellent. That is, the bending strength is about 35% higher than that of Comparative Example 2, which is slightly superior to Comparative Example 1, and the bar flow length is the same as that of Comparative Example 2. It can be seen that fluidity superior to about 1 by about 17% can be obtained.
In addition, in this invention, it can restrict to what is shown to said specific Example, It can be set as the Example variously changed within the range of this invention according to the objective and the use.

  The method for producing a thermoplastic resin composition and the method for producing a molded product of the present invention are widely used in the fields related to automobiles and fields related to 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.

  DESCRIPTION OF SYMBOLS 1; Mixing and melting apparatus, 3; Mixing chamber, 5; Rotating shaft, 10 and 10a-10f; Mixing blade, 12; Spiral blade, 6; Pulley, 7; V belt, 8; Material supply chamber, 21; Load measuring means, 50; Roller disk die type forming part (pelletizing part), 51; Disk die, 511; Through hole, 512; Main rotation shaft insertion hole, 52; Press roller, 521; Part, 53; main rotating shaft, 54; press roller fixing shaft, 55; cutting blade, 61; mold, 611; inlet, 612;

Claims (8)

A method for producing a thermoplastic resin composition comprising a plant material and a thermoplastic resin, wherein the plant material is 50 to 95% by mass when the total of these is 100% by mass,
Using a first mixing and melting apparatus including a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotation shaft, a thermoplastic resin (A1) that is not acid-modified by shearing force generated by the rotation of the mixing blades A first mixing step of mixing the vegetable material, the non-acid-modified thermoplastic resin (A1), and the organic peroxide to obtain a first composition,
Using a second mixing and melting apparatus provided with a mixing tool in which a plurality of mixing blades are erected in the circumferential direction of the rotating shaft, a thermoplastic resin (A2) that is not acid-modified by the shearing force generated by the rotation of the mixing blades ) And the acid-modified thermoplastic resin (B) are melted together, and the first composition is mixed with the acid-free thermoplastic resin (A2) and the acid-modified thermoplastic resin (B). And a second mixing step for obtaining a second composition, and a method for producing a thermoplastic resin composition.   In the first mixing step, when the total of the plant material and the non-acid-modified thermoplastic resin (A1) is 100 parts by mass, the organic peroxide is 0.01 to 0.5 mass. The method for producing a thermoplastic resin composition according to claim 1, which is a part.   The total of the non-acid-modified thermoplastic resin (A1) used in the first mixing step and the non-acid-modified thermoplastic resin (A2) used in the second mixing step was 100% by mass. 3. The method for producing a thermoplastic resin composition according to claim 1, wherein the non-acid-modified thermoplastic resin (A1) used in the first mixing step is 20 to 50% by mass.   The plant material is 70 to 98% by mass when the total of the plant material and the non-acid-modified thermoplastic resin (A1) in the first mixing step is 100% by mass. The manufacturing method of the thermoplastic resin composition in any one of 1-3.   The non-acid-modified thermoplastic resin (A1) used in the first mixing step, the non-acid-modified thermoplastic resin (A2) used in the second mixing step, and the acid-modified thermoplastic resin (B The thermoplastic resin composition according to any one of claims 1 to 4, wherein the acid-modified thermoplastic resin (B) is 1 to 30% by mass when the total is 100% by mass. Manufacturing method.   The method for producing a thermoplastic resin composition according to any one of claims 1 to 5, wherein the plant material is kenaf.   Furthermore, manufacture of the thermoplastic resin composition in any one of the Claims 1 thru | or 6 provided with the pelletization process of compacting and pelletizing the crushed material formed by crushing said 2nd composition, without heating. Method.   A method for producing a molded product, comprising: molding a thermoplastic resin composition obtained by the method for producing a thermoplastic resin composition according to any one of claims 1 to 7 to obtain a molded product.

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