JP2019043978A - Method of producing cellulose-filled resin composition - Google Patents

Abstract

To provide a method of producing a cellulose-filled resin composition capable of forming a molding excellent in slidability.SOLUTION: A method of producing a resin composition comprising thermoplastic resin and cellulose comprises, in the stated order, a first step of preparing a mixture that comprises a dispersion medium containing water as a main constituent and also comprises cellulose dispersed in the dispersion medium, a second step of heating and agitating the mixture and removing the dispersion medium to obtain a cellulose aggregate, and a third step of kneading thermoplastic resin with the cellulose aggregate obtained in the second step. The content of the dispersion medium in the cellulose aggregate obtained in the second step is 0.1 to 10 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a cellulose-filled resin composition.

  In recent years, the noise transmitted to the driver's seat from the engine or road surface of the car is greatly reduced by the adoption of the hybrid engine and the sound absorption performance of the materials around the engine room and tires mainly for luxury cars, and the quietness of the driver's cab It is rising. For this reason, a situation has arisen in which the frictional noise generated from "scrubbing" between parts used indoors, which is caused by the vibration of a car or a shock during driving, which has not been noticed until now, becomes unpleasant.

  In order to suppress the generation of the noise due to the friction, generally, for example, a technique such as adding a low molecular weight compound having slidability and intentionally bleeding out to improve the slidability has been performed. However, there has been a problem that the sliding property is lowered with time.

  It is known that the effect of improving the slidability can be obtained by blending a filler-like substance with a resin, and for example, in Patent Document 1, blending a predetermined amount of inorganic filler in a polylactic acid-based resin and a polyolefin-based resin There is a description of a technique for providing a resin molded body having a reduced coefficient of dynamic friction.

  As described above, the inorganic filler can provide a sliding property improving effect that is unlikely to change with time, but tends to be avoided because it raises the specific gravity of the molded body and goes against weight reduction.

  In recent years, cellulose has come to be used as a new reinforcing material for resins.

Cellulose has a high elastic modulus comparable to that of aramid fibers but has a low true density of 1.56 g / cm ³ and is a common reinforcing material, glass (density 2.4 to 2.6 g / cm ³ ) and talc. It is an overwhelmingly lighter material compared to (density 2.7 g / cm ³ ), and is drawing attention as a reinforcing material for resins in place of glass fibers and the like.

  Therefore, as a technique for dispersing cellulose in a thermoplastic resin up to now, for example, Patent Document 2 applies a lipophilic treatment to powdered cellulose to obtain a mixture uniformly dispersed in a plasticizer, and then melt-kneading it with polyolefin Technology is described. Patent Document 3 describes a technique of mixing a resin, a vegetable fiber swollen in a special liquid, and an organic liquid. Furthermore, in Patent Document 4, water is separated from a mixed dispersion obtained by mixing a cellulose dispersion in advance with a resin powder of a specific particle diameter, and after obtaining a cellulose / resin mixture, a technique of melt-kneading the mixture Is described.

Japanese Patent Application Publication No. 2007-106841 JP, 2016-104874, A International Publication No. 2013/133093 JP, 2008-297364, A

  As in the prior art, in order to impart slidability by the filler, the filler has a moderate average particle size which is neither too fine nor too large, and further has a relatively uniform particle size distribution It is said that it is necessary.

  Generally, in order to blend cellulose into resin, it is necessary to dry and pulverize cellulose in advance, but in the process of separating from water, cellulose becomes a strong aggregate from a finely dispersed state, and it is difficult to redisperse. In the resin composition, the particles after drying are present in a maintained form.

  It is said that it is difficult to control the cellulose in the resin composition to a uniform dispersion diameter, since this cohesive force is expressed by hydrogen bonding by hydroxyl groups of cellulose and is very strong.

  For example, there is a technology in which a TEMPO oxidation catalyst etc. is used to refine to the basic fibril level of cellulose, and then it is blended with a resin, but the cellulose becomes too fine and the contribution to the slidability improvement is small There is a problem of becoming Furthermore, there is also a technology for applying fine shear etc. to cellulose at the time of kneading with a resin by using equipment capable of giving relatively strong shear such as a twin-screw extruder, but in this technology, uniform dispersion state Is difficult to obtain, and it has not come to provide sufficient slidability.

That is, there is currently no technology for improving the slidability of molded articles by controlling the particle size of cellulose inside the molded articles.
An object of the present invention is to solve the above-mentioned problems and to provide a method for producing a resin composition having sufficient slidability which can withstand practical use.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors surprisingly prepared a mixture in which cellulose is dispersed in a water-based dispersion medium, and heat it while heating it. In the step of stirring and removing the dispersion medium to obtain a cellulose aggregate, the amount of dispersion medium contained in the cellulose aggregate is controlled within the range of 0.1 to 10% by mass, whereby the subsequent cellulose aggregate and heat are obtained. In the step of kneading with the plastic resin, a cellulose-filled composition having an appropriate particle size and a highly uniform particle size distribution is obtained, and further, a molded article with significantly reduced rubbing noise at the time of friction is obtained. The inventors have found that the problem of notation can be solved, and have made the present invention.

That is, the present invention includes the following aspects.
[1] A method for producing a resin composition comprising a thermoplastic resin and cellulose,
A first step of preparing a mixture containing a dispersion medium containing water as a main component and cellulose dispersed in the dispersion medium,
A second step of stirring the mixture while heating and removing the dispersion medium to obtain a cellulose aggregate; and a third step of kneading the cellulose aggregate obtained in the second step and the thermoplastic resin,
In this order,
The manufacturing method of the resin composition whose ratio of the dispersion medium contained in the cellulose aggregate obtained at 2nd process is 0.1-10 mass%.
[2] The method for producing a resin composition according to the above aspect 1, wherein the cellulose is cellulose fiber, cellulose whisker or a mixture thereof.
[3] The method for producing a resin composition according to the above aspect 1 or 2, wherein the average particle size of the cellulose aggregate is 0.1 to 100 μm.
[4] The method for producing a resin composition according to any one of the above Embodiments 1 to 3, wherein the proportion of cellulose contained in the mixture obtained in the first step is 1 to 30% by mass.
[5] The resin composition according to any one of the above aspects 1 to 4, wherein the second step is carried out by any one selected from a single-screw extruder, a twin-screw extruder, a kneader, a planetary mixer, and a Lycai machine. Method of manufacturing objects.
[6] The method for producing a resin composition according to any one of the above Embodiments 1 to 5, wherein at least a part of the third step is carried out under reduced pressure below atmospheric pressure.
[7] The production of the resin composition according to any one of the above aspects 1 to 6, wherein the volume ratio of the cellulose aggregate having a diameter of 1 μm or more is 0.1 to 50% by volume with respect to 100% by volume of the resin composition. Method.

  The present invention can provide a method capable of producing a thermoplastic resin composition capable of providing a resin molded body in which the generation of noise caused by "scrubbing" is suppressed.

  The present invention will be specifically described below with reference to exemplary embodiments of the present invention, but the present invention is not limited to these embodiments.

  The method for producing a resin composition of the present invention is a method for producing a resin composition containing a thermoplastic resin and cellulose. The present manufacturing method includes a first step, a second step and a third step. The following will be described in order.

«First step»
In the present production method, a first step of preparing a mixture in which cellulose is dispersed in a dispersion medium containing water as a main component is required. Although any cellulose may be used here, it is desirable to use fine cellulose in order to disperse it in a resin composition with an appropriate particle diameter. More specifically, cellulose is more preferably cellulose fiber, cellulose whisker or a mixture thereof.

  In the present disclosure, “length” (L) and “diameter” (D) of cellulose correspond to, for example, the major axis and the minor axis in the case of cellulose whiskers, and the fiber length and the fiber diameter in the case of cellulose fibers. As the cellulose whisker and the cellulose fiber, those in which the diameter of the cellulose alone is nanometer size (that is, less than 1 μm) are more preferable from the viewpoint of effectively forming a cellulose aggregate in the second step. Each of the cellulose whiskers and cellulose fibers which can be suitably used in the present invention has a diameter of 500 nm or less. The upper limit of the preferred cellulose diameter is 450 nm, more preferably 400 nm, still more preferably 350 nm, and most preferably 300 nm.

  In a particularly preferred embodiment, the diameter of the cellulose whisker is preferably 20 nm or more, more preferably 30 nm or more, preferably 500 nm or less, more preferably 450 nm or less, still more preferably 400 nm or less, still more preferably 350 nm or less. Most preferably, it is 300 nm or less.

  In a particularly preferred embodiment, the diameter of the cellulose fiber is preferably 1 nm or more, more preferably 5 nm or more, still more preferably 10 nm or more, particularly preferably 15 nm or more, and most preferably 20 nm or more. And preferably 450 nm or less, more preferably 400 nm or less, still more preferably 350 nm or less, still more preferably 300 nm or less, and most preferably 250 nm or less.

  In order to effectively improve the slidability of the molded article made of the resin composition, it is desirable to set the diameter of the cellulose within the above range.

  Cellulose whiskers in the present invention refer to crystalline cellulose remaining after dissolving amorphous portions of cellulose in an acid such as hydrochloric acid or sulfuric acid after cutting pulp and the like as raw materials.

  In addition, cellulose fibers were treated with hot water at 100 ° C. or higher to hydrolyze hemicellulose parts and make them brittle, and then fibrillated by a pulverizing method such as a high-pressure homogenizer, microfluidizer, ball mill or disc mill. Cellulose and cellulose fiber which is fibrillated not by strong mechanical fibrillation such as pulverization but by TEMPO oxidation method or conversion modification of cellulose fiber hydroxyl group in an organic solvent is included.

  The preferred length / diameter ratio (L / D ratio) of the cellulose whiskers is less than 30. The L / D upper limit of the cellulose whisker is preferably 25, more preferably 20, more preferably 15, still more preferably 10, and most preferably 5. Although the lower limit is not particularly limited, it may be more than 1. In order to impart appropriate fluidity to the resin composition, it is desirable that the L / D ratio of the cellulose whiskers be within the above-mentioned range.

  The L / D lower limit of the cellulose fiber is preferably 30, more preferably 50, more preferably 80, still more preferably 100, particularly preferably 120, and most preferably 150. . The upper limit is not particularly limited, but is preferably 1000 or less from the viewpoint of not excessively increasing the melt viscosity of the resin composition.

  In the present disclosure, the length, diameter, and L / D ratio of each of the cellulose whisker and the cellulose fiber are each an aqueous dispersion of the cellulose whisker and the cellulose fiber as a high shear homogenizer (for example, a product manufactured by Nippon Seiki Co., Ltd.) Using the name "Excel Auto Homogenizer ED-7" and processing conditions: Dilute the aqueous dispersion dispersed at a rotational speed of 15,000 rpm x 5 minutes with pure water to 0.1 to 0.5 mass%, Mica It is cast on top and air-dried to obtain a measurement sample, which is determined by measurement with a high resolution scanning microscope (SEM) or an atomic force microscope (AFM). Specifically, the length (L) and diameter (D) of the 100 randomly selected celluloses, and the ratio (D) in the observation field of view adjusted to have at least 100 celluloses, and the magnification (mm) Confirmation is possible by calculating L / D. The cellulose length and diameter of the present disclosure are a number average value of a total of 100 celluloses. For each of the cellulose whisker and the cellulose fiber, the number average value of the length (L), the number average value of the diameter (D), and the number average value of the ratio (L / D) are calculated And the length, diameter, and L / D ratio of each of the cellulose fibers. Further, in the present disclosure, the cellulose whisker and the cellulose fiber can be distinguished from each other by classifying the one having a ratio (L / D) of less than 30 as the cellulose whisker and the one having 30 or more as the cellulose fiber.

  Alternatively, the length, diameter, and L / D ratio of each of the cellulose whiskers and the cellulose fibers in the composition can be confirmed by measuring the composition which is a solid as a measurement sample by the above-described measurement method. .

  Alternatively, the length, diameter, and L / D ratio of each of the cellulose whisker and the cellulose fiber in the composition are such that the resin component in the composition is dissolved in an organic or inorganic solvent capable of dissolving the resin component of the composition; After separating the cellulose and thoroughly washing with the above solvent, an aqueous dispersion in which the solvent is replaced with pure water is prepared, and diluted with pure water so that the cellulose concentration is 0.1 to 0.5 mass%, It can be confirmed by measuring one cast on mica and air-dried as a measurement sample by the above-mentioned measurement method. At this time, the measurement of the cellulose to be measured is a total of 200 or more of 100 or more cellulose fibers having L / D randomly selected of 30 or more and 100 or more of cellulose whiskers having L / D less than 30.

  Cellulose whiskers preferably usable in the present invention are cellulose whiskers having a crystallinity of 55% or more. When the degree of crystallinity is in this range, the mechanical properties (strength and dimensional stability) of the cellulose whisker itself are enhanced, and thus when dispersed in a resin, the strength and dimensional stability of the resin composition tend to be high.

  The crystallinity of the cellulose whisker is preferably 60% or more, more preferably 65%, still more preferably 70%, and most preferably 80%. The higher the degree of crystallinity of the cellulose whisker tends to be, the upper limit is not particularly limited, but 99% is the preferred upper limit from the viewpoint of production.

  Moreover, the cellulose fiber whose crystallinity degree is 55% or more can use the cellulose fiber suitably. When the degree of crystallinity is in this range, the mechanical properties (strength and dimensional stability) of the cellulose fiber itself are enhanced, and therefore, when dispersed in a resin, the strength and dimensional stability of the resin composition tend to be high. The lower limit of the degree of crystallinity is more preferably 60%, still more preferably 70%, and most preferably 80%. The upper limit of the crystallinity of the cellulose fiber is also not particularly limited, and is preferably higher, but the upper limit is preferably 99% from the viewpoint of production.

  The crystallinity of cellulose whiskers and cellulose fibers depends on the degree of removal of the noncrystalline portion during the production of these celluloses, but under production conditions where the degree of removal of the noncrystalline portion is high, removal of impurities such as lignin The degree also increases. If the residual amount of impurities such as lignin is large, color change may occur due to heat at the time of processing of the resin composition, and from the viewpoint of suppressing the color change of the resin composition at the time of extrusion processing and molding processing, cellulose whiskers and It is desirable that the crystallinity of the cellulose fiber be in the above-mentioned range.

The degree of crystallinity as referred to herein is Segal from the diffraction pattern (2θ / deg .: 10 to 30) when the sample is measured by wide-angle X-ray diffraction when the cellulose is type I cellulose (derived from natural cellulose). By the law, it is obtained by the following equation.
Crystallinity (%) = ([diffraction intensity attributable to (200) plane at 2θ / deg. = 22.5] − [diffraction intensity attributable to amorphous at 2θ / deg. = 18] / [2θ / Deg. Diffraction intensity attributable to (200) plane of 22.5] × 100
When the cellulose is type II crystal (derived from regenerated cellulose), the degree of crystallinity is 2θ = 12.6 ° attributed to the (110) plane peak of type II crystal in wide-angle X-ray diffraction. From the absolute peak intensity h0 and the peak intensity h1 from the baseline at this interplanar spacing, it is obtained by the following equation.
Crystallinity (%) = h1 / h0 × 100

  As crystal forms of cellulose, type I, type II, type III, type IV and the like are known, and type I and type II celluloses are widely used, while type III and type IV celluloses are laboratory scale Although it is obtained, it is not used widely on the industrial scale. As the cellulose used in the present invention, a resin composite is relatively high in structural mobility, has a lower linear expansion coefficient by dispersing the cellulose in a resin, and is more excellent in strength and elongation at the time of tensile deformation and bending. It is preferable that the cellulose contains cellulose I-type crystals or cellulose II-type crystals, and more preferably cellulose containing cellulose I-type crystals and having a crystallinity of 55% or more.

  The degree of polymerization of the cellulose whisker is preferably 100 or more, more preferably 120 or more, more preferably 130 or more, more preferably 140 or more, more preferably 150 or more, preferably 300 or less, more preferably It is 280 or less, more preferably 270 or less, more preferably 260 or less, more preferably 250 or less. The degree of polymerization of the cellulose fiber is preferably 400 or more, more preferably 420 or more, more preferably 430 or more, more preferably 440 or more, more preferably 450 or more, preferably 2500 or less, more preferably 2300 Or less, more preferably 2200 or less, more preferably 2100 or less, more preferably 2000 or less. It is preferable that the degree of polymerization of cellulose whiskers and cellulose fibers is not too high from the viewpoint of processability in extrusion molding and mechanical properties of molded articles, and it is desirable that the degree of polymerization is not too low from the viewpoint of mechanical properties.

  The degree of polymerization of cellulose whiskers and cellulose fibers is the average degree of polymerization measured according to the reduction specific viscosity method by the copper ethylenediamine solution described in the confirmation test (3) of “15th Amendment Japanese Pharmacopoeia Explanation Book (issued by Yodogawa Shoten)” Means

  A hydrolysis process etc. are mentioned as a method of controlling the polymerization degree (namely, average polymerization degree) of a cellulose. By the hydrolysis treatment, depolymerization of the amorphous cellulose inside the cellulose fiber proceeds, and the average degree of polymerization decreases. At the same time, by the hydrolysis treatment, in addition to the above-mentioned amorphous cellulose, impurities such as hemicellulose and lignin are also removed, so that the inside of the fiber becomes porous. As a result, in the step of applying mechanical shear such as the extrusion step described later, the cellulose component is easily subjected to mechanical processing, and the cellulose component is easily refined.

  Although the method of hydrolysis is not particularly limited, acid hydrolysis, alkali hydrolysis, hydrothermal decomposition, steam explosion, microwave decomposition and the like can be mentioned. These methods may be used alone or in combination of two or more. In the method of acid hydrolysis, for example, α-cellulose obtained as pulp from fibrous plants is used as a cellulose raw material and dispersed in an aqueous medium, and an appropriate amount of protonic acid, carboxylic acid, Lewis acid, heteropoly acid etc. In addition, the average degree of polymerization can be easily controlled by heating while stirring. The reaction conditions such as temperature, pressure and time in this case vary depending on the cellulose species, cellulose concentration, acid species and acid concentration, but are appropriately adjusted so as to achieve the target average polymerization degree. For example, the conditions of processing a cellulose for 10 minutes or more under 100 degreeC or more and under pressure using mineral acid solution of 2 mass% or less are mentioned. Under this condition, the catalyst component such as acid penetrates to the inside of the cellulose fiber to accelerate the hydrolysis, the amount of the catalyst component used decreases, and the subsequent purification becomes easy. In addition to the water, a small amount of an organic solvent may be contained in the dispersion of the cellulose raw material at the time of hydrolysis, as long as the effects of the present invention are not impaired.

  From the viewpoint of the ease of formation of the cellulose aggregate in the second step, it is desirable to set the degree of polymerization of the cellulose whisker and the cellulose fiber within the above range. By using cellulose having a degree of polymerization suitable for each, it is considered that it becomes easy to form an aggregate having an appropriate particle size distribution.

  The dispersion medium used in the first step is a dispersion medium containing water as a main component. Here, having water as the main component means that the proportion of water in the dispersion medium is 50% by mass or more. As the dispersion medium other than water, for example, an organic solvent compatible with water, an organic solvent incompatible with water, a surfactant and the like can be exemplified.

  Organic solvents compatible with water include not only organic solvents miscible with water in any composition range, but also organic solvents miscible in a specific composition range. Specific examples thereof include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, ethylene glycol, tetrahydrofuran, acetone, methyl ethyl ketone, acetonitrile, dimethylformamide, triethylamine, pyridine, dimethylsulfoxide, acetic acid and the like. It is not limited.

  Further, an organic solvent incompatible with water refers to an organic solvent which is hardly soluble in water with a solubility of 1% by mass or less. Specific examples thereof include, but are not limited to, ethyl acetate, dichloromethane, chloroform, carbon tetrachloride, toluene, xylene, cyclohexane, pentane, heptane and the like.

  Furthermore, as the surfactant, any of anionic surfactants, nonionic surfactants, amphoteric surfactants and cationic surfactants can be used, but the affinity with cellulose is also possible. From the point of point of view, anionic surfactants and nonionic surfactants are preferable, and nonionic surfactants are more preferable.

  Examples of the anionic surfactant include fatty acid sodium (fatty acid type (anion)), fatty acid sodium, fatty acid potassium, alpha sulfo fatty acid ester sodium and the like, and linear alkyl benzene type and the like, linear sodium alkyl benzene sulfonate etc. Examples of the alcohol type (anion) include sodium alkyl sulfate, sodium alkyl ether sulfate and the like, an alpha olefin type such as sodium alpha olefin sulfonate, and a normal paraffin type such as sodium alkyl sulfonate, etc. It is also possible to use species or a mixture of two or more species.

  Examples of nonionic surfactants include fatty acid type (nonionic), glycolipids such as sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide, etc. Examples of the ion) include polyoxyethylene alkyl ether and the like, and examples of the alkyl phenol include polyoxyethylene alkyl phenyl ether and the like. It is also possible to use one or two or more of them in combination.

  Examples of the amphoteric surfactant include an alkylamino fatty acid sodium etc. as an amino acid system, an alkyl betaine etc. as a betaine system, an alkylamine oxide etc. as an amine oxide system, one or two of them are listed. It is also possible to mix and use species or more.

  As a cationic surfactant, as a quaternary ammonium salt, alkyltrimethyl ammonium salt, dialkyl dimethyl ammonium salt and the like can be mentioned, and it is possible to use one or two or more of them in combination. .

  The surfactant may be a derivative of a fat. As fats and oils, esters of fatty acids and glycerin are mentioned, and those in the form of triglyceride (tri-O-acylglycerin) are usually mentioned. Oils that are oxidized with fatty oil and classified as dry oil, semi-dry oil, non-dry oil in order of easy setting can be used for various applications such as food and industrial use, for example, the following: It can be used 1 type or in combination of 2 or more types.

  As fats and oils, for example, terpin oil, tall oil, rosin, white oil, corn oil, soybean oil, sesame oil, rapeseed oil (canola oil), rice bran oil, soy sauce, soy sauce, soy flour, safflower oil (safflower oil) Palm oil (palm kernel oil), cottonseed oil, sunflower oil, sesame oil (soybean oil), linseed oil, olive oil, peanut oil, almond oil, avocado oil, hazelnut oil, walnut oil, grape seed oil, mustard oil, Lettuce oil, fish oil, soy sauce, soy sauce, liver oil, cocoa butter, peanut butter, palm oil, lard (pork fat), het (cow butter), chicken oil, tallow oil, sheep fat, horse fat, schumart, milk fat (butter, Gee), hardened oil (margarine, shortening etc.), castor oil (vegetable oil) etc.

  In a particularly preferred embodiment, the surfactant is one or more selected from the group consisting of rosin derivatives, alkylphenyl derivatives, bisphenol A derivatives, beta-naphthyl derivatives, styrenated phenyl derivatives, and hydrogenated castor oil derivatives.

  A mixture containing a water-based dispersion medium and cellulose dispersed in the dispersion medium can be obtained by various methods. As a specific example, the raw material pulp and the like is treated with hot water at 100 ° C. or higher to hydrolyze and weaken the hemicellulose portion, and then the pulverization method such as high-pressure homogenizer, microfluidizer, ball mill or disc mill Method of disentanglement, Pulp as raw material is cut, and after dissolving non-crystalline part of cellulose in acid such as hydrochloric acid and sulfuric acid, neutralization method, raw material pulp etc is crushed, hot water of 100 ° C or more etc. The pulp obtained by dewatering and dewatering is stirred with a stirrer, defibrillated and modified with a bead mill or the like in an atmosphere of an organic solvent, and the like, followed by water substitution of the solvent, and the like.

  In addition, the mixture prepared as described above is dried under shear conditions, and obtained as powdered cellulose, and then blended so as to obtain a desired cellulose concentration, and then mixed with a dispersion medium, a high pressure homogenizer, a microfluidizer, a ball mill, It is also possible to suitably use a method in which shear is applied and redispersed under device conditions such as a disk mill which gives shear.

  The preferable cellulose ratio of the mixture obtained in the first step is 1 to 30% by mass based on 100% by mass of the mixture. The more preferable amount depends on the type of cellulose used and the ratio thereof.

  Specifically, when the cellulose type is cellulose fiber alone, the lower limit amount is more preferably 1.5% by mass, still more preferably 2.0% by mass, and still more preferably 2.5% by mass. Most preferably 3.0% by weight. Also, considering the addition efficiency, the higher the cellulose ratio, the better, but from the viewpoint of handleability, the upper limit amount is more preferably 25% by mass, still more preferably 23% by mass, still more preferably 20% by mass. %, Most preferably 18% by weight.

  When the cellulose type is cellulose whisker alone, the lower limit amount is more preferably 4% by mass, still more preferably 6% by mass, still more preferably 8% by mass, and most preferably 10% by mass . The upper limit value is more preferably 29% by mass, still more preferably 28% by mass, still more preferably 27% by mass, and most preferably 25% by mass.

  In the case where the cellulose species is a mixture of cellulose fiber and cellulose whisker, the preferred quantitative ratio is between the above. Specifically, the lower limit amount is more preferably 1.5% by mass, still more preferably 2.0% by mass, still more preferably 2.5% by mass, and most preferably 3.0% %, And the upper limit amount is more preferably 29% by mass, still more preferably 28% by mass, even more preferably 27% by mass, and most preferably 25% by mass.

  By setting the amount to the above lower limit or more, it becomes easy to obtain a resin composition containing high concentration of cellulose, and by setting the amount to the upper limit or less, it is easy to express the advantage that the transfer of the mixture by the pump becomes easy. .

«Second process»
In the present production method, a second step, which is performed following the first step, is necessary while stirring the mixture prepared in the first step while heating to remove the dispersion medium to obtain a cellulose aggregate. .

  This step is a step extremely important for the development of the slidability of the composition obtained by the production method of the present invention. In particular, in this step, the mixture prepared in the first step is stirred while being heated, and the amount of the dispersion medium contained in the obtained cellulose aggregate is 100% by mass of the cellulose aggregate, 0.1 It is necessary to control in the range of -10 mass%.

  The lower limit of the amount of the dispersion medium is preferably 0.5% by mass, more preferably 0.8% by mass, still more preferably 1% by mass, and most preferably 1.5% by mass. The upper limit of the amount of the dispersion medium is preferably 8% by mass, more preferably 6% by mass, still more preferably 5% by mass, particularly preferably 4% by mass, and most preferably 3% by mass.

  By controlling the amount of the dispersion medium within the above-mentioned range, it is possible to reduce the frictional noise when the molded product obtained from the production method of the present invention is rubbed.

  Although the cause of occurrence of the frictional noise reduction effect is not clear, the cellulose aggregate in a state in which a suitable dispersion medium is contained is stronger between the celluloses than the cellulose aggregate having a smaller content of the dispersion medium. Aggregation can be easily suppressed, and the formation of huge cellulose particles can be suppressed, so that the particle diameter can be easily made uniform, and when it is melted with a molten resin as compared to a cellulose aggregate in which a larger amount of dispersion medium remains. The heat removal due to the evaporation latent heat is suppressed, and the kneading time with the molten resin becomes long, so it is considered that it is because it becomes easy to control the average particle diameter.

  The amount of dispersion medium contained in the cellulose aggregate in the second step of the present invention can be determined by the vaporization method. Specifically, confirmation can be made by measuring the amount of dispersion medium generated from the cellulose aggregate heated to 100 ° C. or higher. More specifically, the amount of the dispersion medium can be determined from the weight change before and after drying when the cellulose aggregate is dried by a dryer heated to 100 ° C. or higher. In order to maintain accuracy more, it is desirable to calculate from the weight change before and after drying when dried for 5 hours or more under reduced pressure with a vacuum dryer set at 100 ° C. or higher. The upper limit temperature at this time is preferably 150.degree.

  The processing machine used in the second step in the present invention can be used without any problem as long as it can stir while heating, but examples include extruders such as single- or twin-screw, kneaders, Examples include planetary mixers, and rye-chairs.

  Among these, in particular, a twin-screw extruder, a planetary mixer, and a lycai machine can be preferably used, and a planetary mixer and a lycai machine can be particularly preferably used.

  Although it is important to heat in the second step in the present invention, the specific heating temperature is preferably 30 ° C. or more and less than 150 ° C., which varies depending on the degree of pressure reduction. The lower limit temperature is preferably 30 ° C, more preferably 40 ° C, and most preferably 50 ° C. The upper limit temperature is more preferably 130 ° C., still more preferably 120 ° C., particularly preferably 110 ° C., and most preferably 100 ° C. By setting it as the above-mentioned temperature range, it becomes easy to control the amount of dispersion media in a cellulose aggregate in a desired range.

  In addition, it is also useful as a process to make a reduced pressure environment at the time of heating. By using a reduced pressure environment, it is possible to obtain an advantage that heating at a lower temperature is possible and the process window becomes larger.

  In the second step of the present invention, it is also necessary to stir. The stirring conditions can affect the average particle size and the particle size uniformity of the cellulose aggregate as well as the temperature conditions. The specific amount of agitation depends on the type of processing machine, but is preferably in the range of 10 to 1000 rpm. The lower limit rotational speed is more preferably 20 rpm, still more preferably 30 rpm, and most preferably 40 rpm. The upper limit rotational speed is more preferably 800 rpm, still more preferably 600 rpm, particularly preferably 500 rpm, and most preferably 400 pm. In order to control the average particle size and the particle size uniformity of the cellulose aggregate and to obtain a molded article having high slidability, it is desirable to be in the above-mentioned range.

  In the present invention, the average particle diameter of the cellulose aggregate obtained in the second step is desirably 0.1 to 100 μm. It is desirable to control to the above-mentioned average particle diameter by heating and stirring a mixture containing cellulose and a dispersion medium in the second step. By setting it in the above-mentioned range, it becomes possible to suppress the generation of the sound due to the rubbing of the molded body. The lower limit of the average particle size is more preferably 0.2 μm, still more preferably 0.5 μm, still more preferably 0.8 μm, and most preferably 1 μm. The upper limit of the average particle size is more preferably 80 μm, still more preferably 70 μm, still more preferably 60 μm, and most preferably 50 μm.

  Here, the average particle size of the cellulose aggregate is obtained by dispersing the cellulose aggregate obtained in the second step with a laser diffraction particle size distribution measuring apparatus (for example, SALD-2300: manufactured by Shimadzu Corporation etc.) It is the value measured using water as a medium. Specifically, the central value of the number average particle size distribution is represented.

«Third step»
In the present invention, following the second step, it is necessary to provide a third step of kneading the cellulose aggregate obtained in the second step and the thermoplastic resin. In a preferred embodiment, at least part of the third step is carried out at a reduced pressure below atmospheric pressure.

(Thermoplastic resin)
The thermoplastic resin used in the present invention may be a crystalline resin having a melting point in the range of 100 ° C. to 350 ° C., or an amorphous resin having a glass transition temperature in the range of 100 to 250 ° C. .

  The melting point of the crystalline resin as referred to herein means a peak top temperature of an endothermic peak which appears when the temperature is raised at a temperature rising rate of 23 ° C. to 10 ° C./min using a differential scanning calorimeter (DSC). When two or more endothermic peaks appear, it refers to the peak top temperature of the endothermic peak on the highest temperature side. The enthalpy of the endothermic peak at this time is preferably 10 J / g or more, and more preferably 20 J / g or more. Further, in the measurement, it is desirable to use a sample cooled to 23 ° C. at a temperature drop rate of 10 ° C./min after melting the resin by once heating the sample to a temperature condition of melting point + 20 ° C. or higher.

  The glass transition temperature of the non-crystalline resin as referred to herein is measured at an applied frequency of 10 Hz while raising the temperature at a temperature rising rate of 23 ° C. to 2 ° C./min using a dynamic viscoelasticity measuring apparatus. The temperature at the peak top of the peak where the storage elastic modulus is greatly reduced and the loss elastic modulus is maximized. When two or more peaks of loss modulus appear, the peak top temperature of the peak on the highest temperature side is indicated. The measurement frequency at this time is preferably at least once every 20 seconds in order to improve the measurement accuracy. The method of preparing the measurement sample is not particularly limited, but from the viewpoint of eliminating the influence of molding strain, it is desirable to use the cut-out piece of the heat press-formed product, and the size (width and thickness) of the cut-out piece is as small as possible The smaller one is desirable from the viewpoint of heat conduction.

  Specific examples of thermoplastic resins that can be suitably used in the present invention include polyolefin resins, polyamide resins, polyester resins, polyacetal resins, polyphenylene ether resins, polyphenylene sulfide resins, and mixtures of two or more of these. However, the present invention is not limited thereto.

  Among these, polyolefin resins, polyamide resins, polyester resins, polyacetal resins and the like are more preferable resins from the viewpoint of handling property and cost, and polyamide resins are particularly preferable.

  The polyolefin resin preferable as a thermoplastic resin is a polymer obtained by polymerizing olefins (for example, α-olefins) and alkenes as monomer units. Specific examples of polyolefin resins include ethylene (co) polymers exemplified by low density polyethylene (for example, linear low density polyethylene), high density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene -Polypropylene-based copolymer, polypropylene-based copolymer exemplified by ethylene-propylene-diene copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer The copolymer etc. of alpha-olefins, such as ethylene represented by coalescence etc., are mentioned.

  Polypropylene is mentioned as the most preferable polyolefin resin here. In particular, polypropylene having a melt mass flow rate (MFR) measured at 230 ° C. and a load of 21.2 N in accordance with ISO 1133 is preferably 3 g / 10 minutes to 30 g / 10 minutes. The lower limit value of MFR is more preferably 5 g / 10 min, still more preferably 6 g / 10 min, and most preferably 8 g / 10 min. The upper limit is more preferably 25 g / 10 minutes, still more preferably 20 g / 10 minutes, and most preferably 18 g / 10 minutes. MFR preferably does not exceed the above upper limit value from the viewpoint of improving the toughness of the composition, and desirably does not exceed the above lower limit value from the viewpoint of the flowability of the composition.

  Moreover, in order to raise affinity with a cellulose, acid-modified polyolefin resin can also be used conveniently. The acid in this case can be appropriately selected from maleic acid, fumaric acid, succinic acid, phthalic acid and their anhydrides, and polycarboxylic acids such as citric acid. Among these, maleic acid or an anhydride thereof is preferable because of high easiness of modification rate. The modification method is not particularly limited, but a general method is to melt and knead by heating above the melting point in the presence / absence of a peroxide. As the acid-modified polyolefin resin, all the above-mentioned polyolefin resins can be used, but among them, polypropylene can be suitably used. The acid-modified polypropylene may be used alone, but in order to adjust the rate of modification as a composition, it is more preferable to use it in combination with non-modified polypropylene. The ratio of acid-modified polypropylene to all polypropylenes in this case is 0.5% by mass to 50% by mass. A more preferable lower limit is 1% by mass, more preferably 2% by mass, still more preferably 3% by mass, particularly preferably 4% by mass, and most preferably 5% by mass. The upper limit is more preferably 45% by mass, still more preferably 40% by mass, still more preferably 35% by mass, particularly preferably 30% by mass, and most preferably 20% by mass. In order to maintain the interfacial strength with cellulose, the lower limit or more is preferable, and in order to maintain the ductility as the resin, the upper limit or less is preferable.

  The preferred melt mass flow rate (MFR) of acid-modified polypropylene as measured at 230 ° C. and 21.2 N load according to ISO 1133 is 50 g / 10 min or more in order to enhance the affinity to the cellulose interface Is preferred. A more preferred lower limit is 100 g / 10 min, even more preferably 150 g / 10 min, most preferably 200 g / 10 min. The upper limit is not particularly limited, but a preferable upper limit is 500 g / 10 minutes in order to maintain mechanical strength. By making MFR into this range, the advantage that acid-modified polypropylene is easily present at the cellulose-resin interface can be enjoyed.

  As an example of a polyamide resin preferable as a thermoplastic resin, polyamide 6, polyamide 11, polyamide 12 obtained by polycondensation reaction of lactams, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 1,7-heptanediamine, 2-methyl-1-6-hexanediamine, 1,8-octanediamine, 2-methyl-1,7-heptanediamine, 1,9-nonanediamine, 2-methyl-1,8- Octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, diamines such as m-xylylenediamine, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid Octanedioic acid, nonanedioic acid, decanedioic acid, benzene-1,2-dicarboxylic acid, benzene-1,3-di Polyamide 6,6, polyamide 6,10 obtained as a copolymer with dicarboxylic acids such as carboxylic acid, benzene-1,4 dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, etc. , Polyamide 6,12, polyamide 6,12, polyamide 6, T, polyamide 6, I, polyamide 9, T, polyamide 10, T, polyamide 2M5, T, polyamide MXD, 6, polyamide 6, C, polyamide 2M5, C And copolymers obtained by copolymerizing these, for example, copolymers of polyamide 6, T / 6, I and the like.

  Among these polyamide resins, aliphatic polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 6,6, polyamide 6,10, polyamide 6,11, polyamide 6,12, polyamide 6, C, polyamide 2 M5, C Are more preferred, and polyamide 6 and polyamide 6,6 are particularly preferred.

  As polyester resins preferable as the thermoplastic resin in the present invention, polyethylene terephthalate (hereinafter sometimes referred to simply as PET), polybutylene succinate (polyester resin consisting of aliphatic polyvalent carboxylic acid and aliphatic polyol (described below) (Also referred to as unit PBS), polybutylene succinate adipate (hereinafter sometimes simply referred to as PBSA), polybutylene adipate terephthalate (hereinafter sometimes simply referred to as PBAT), polyhydroxyalkanoate (3- Polyester resin consisting of hydroxyalkanoic acid (hereinafter sometimes simply referred to as PHA), polylactic acid (hereinafter sometimes referred to simply as PLA), polybutylene terephthalate (hereinafter sometimes referred to simply as PBT), polyethylene naphtha Les At least one selected from the group consisting of P (hereinafter sometimes referred to simply as PEN), polyarylate (hereinafter sometimes referred to simply as PAR), polycarbonate (hereinafter sometimes referred to simply as PC), etc. It can be used.

  Among these, more preferable polyester resins include PET, PBS, PBSA, PBT, and PEN, and more preferably PBS, PBSA, and PBT.

  The polyacetal resin preferable as a thermoplastic resin in the present invention is generally a homopolyacetal using formaldehyde as a raw material, and a copolyacetal containing trioxane as a main monomer and 1,3-dioxolane as a comonomer component, both of which are used Although possible, copolyacetal can be preferably used from the viewpoint of heat stability at the time of processing. In particular, the amount of the comonomer component (eg, 1,3-dioxolane) is more preferably in the range of 0.01 to 4 mol%. The preferable lower limit of the amount of the comonomer component is 0.05 mol%, more preferably 0.1 mol%, still more preferably 0.2 mol%. The upper limit is preferably 3.5 mol%, more preferably 3.0 mol%, still more preferably 2.5 mol%, and most preferably 2.3 mol%.

  From the viewpoint of thermal stability during extrusion processing and molding processing, the lower limit is preferably in the above range, and from the viewpoint of mechanical strength, the upper limit is preferably in the above range.

As for the thermoplastic resin used in the present invention, it is desirable that the ratio of the thermoplastic resin in pellet form (pellet ratio) is more than 50 mass% in 100 mass% of the thermoplastic resin. The lower limit of the pellet ratio is more preferably 70% by mass, still more preferably 80% by mass, particularly preferably 90% by mass, most preferably 100% by mass (that is, substantially all in pellet form) . In order to break up and disperse the cellulose aggregate by friction with the cellulose aggregate in the extruder, it is desirable to increase the pellet ratio within the above-mentioned range.
Examples of processing equipment that can be preferably used in the third step of the present invention include an extruder, a kneader and the like, among which an extruder is preferable, and a twin-screw extruder is particularly preferable in controlling the dispersibility of cellulose.

  Further, as the extruder, one having L / D obtained by dividing the cylinder length (L) by the screw diameter (D) is preferably 40 or more. Particularly preferably, it is 50 or more. Moreover, as for screw rotation speed at the time of kneading | mixing, the range of 100-800 rpm is desirable. More preferably, it is in the range of 150 to 600 rpm. These vary with the design of the screw.

  The resin composition obtained by the process of the present invention preferably contains a cellulose aggregate in an appropriate amount in the resin composition. This appropriate content is effective in suppressing the generation of sound when the molded article is rubbed. The amount of cellulose aggregates present in 100% by volume of the resin composition is preferably 0.1 to 50% by volume. The lower limit amount is more preferably 0.5% by volume, still more preferably 0.8% by volume, still more preferably 1% by volume, and most preferably 1.2% by volume. The upper limit amount is more preferably 15% by volume, still more preferably 10% by volume, still more preferably 5% by volume, still more preferably 4% by volume, particularly preferably 3.5% by volume, most preferably 3 It is volume%.

  The amount of the cellulose aggregate in the resin composition in the present invention is, for example, optionally cutting out a part of the molded product made of the resin composition, and using a high resolution 3DX line microscope (nano3DX: manufactured by Rigaku Corporation etc.) It is possible to confirm by calculating CT measurement and performing binarization of the obtained data, then dividing the volume detected as an object in the composition by the total volume and calculating it as foreign matter volume% is there. At this time, the size of the aggregate to be detected is, for example, 1 μm or more.

  Further, in the present invention, in addition to the above-described components, additional components may be added as needed, as long as the effects of the present invention are not impaired. The addition amount of these additional components is desirably in a range not exceeding 15 parts by mass when the total amount of the resin composition is 100 parts by mass.

  Examples of additional components include additional thermoplastic resins, inorganic fillers (talc, kaolin, zonotrite, wollastonite, potassium titanate, glass fibers, etc.), known to increase the affinity of the inorganic filler with the resin. Silane coupling agents, flame retardants (halogenated resins, silicone flame retardants, magnesium hydroxide, aluminum hydroxide, organic phosphoric acid ester compounds, ammonium polyphosphate, red phosphorus, etc.) Plasticizers (oil, low molecular weight polyolefin, polyethylene glycol, fatty acid esters etc.), flame retardant aids such as antimony trioxide, colorants such as carbon black for coloring, antistatic agents, various peroxides, antioxidants, UV absorbers, light stabilizers and the like can be mentioned.

  The production method of the present invention makes it possible to highly disperse cellulose in a thermoplastic resin, thereby improving the extensional viscosity of the obtained resin composition, and can be used for materials which are stretched in the molten state, etc. . Specifically, it can be suitably used for various large-sized parts applications molded by large-sized sheet molding, blow molding, vacuum molding, inflation molding and the like. Of course, even in the case of ordinary injection molded products, stable physical properties can be obtained due to the high dispersibility of cellulose, and therefore automotive exterior materials requiring reliability, structural members such as chassis, driving members such as interior members, gears, etc. It can be suitably used.

  The present invention will be further described based on examples, but the present invention is not limited to these examples.

[Raw materials and evaluation method]
Below, the used raw material and evaluation method are demonstrated.

«Thermoplastic resin»
Polyamide Polyamide 6 (hereinafter simply referred to as PA)
"UBE nylon 1013B" available from Ube Industries, Ltd.

«Evaluation method»
Degree of polymerization of cellulose
It measured by the reduction specific viscosity method by the copper ethylenediamine solution prescribed | regulated to the crystalline cellulose confirmation test (3) of "the 14th revision Japanese Pharmacopoeia" (Ashikawa Shoten publication).

<Crystal form of cellulose component, degree of crystallinity>
The diffraction image was measured (normal temperature) by a powder method using an X-ray diffractometer (multipurpose X-ray diffractometer manufactured by Rigaku Corporation), and the degree of crystallinity was calculated by the Segal method. In addition, the crystal form was also measured from the obtained X-ray diffraction image.

<Cellulose L / D>
A cellulose is made into a pure water suspension at a concentration of 1% by mass, and it is treated with a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7, treatment conditions: rotation speed 15,000 rpm x 5 minutes) The dispersed aqueous dispersion was diluted with pure water to 0.1 to 0.5% by mass, cast on mica, and air-dried particle images were observed with an atomic force microscope (AFM). The major axis (L) and minor axis (D) of the particle image were measured, and the ratio (L / D) was further determined from these values, and calculated as an average value of 100 to 150 particles.

<Average diameter of cellulose>
A solid content of 40% by mass of cellulose is kneaded for 30 minutes at room temperature and normal pressure at 126 rpm in a planetary mixer (trade name “5DM-03-R”, manufactured by Shinagawa Kogyo Co., Ltd., trade name) did. Next, a pure water suspension was prepared at a concentration of 0.5% by mass of solid content, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name “Excel Auto Homogenizer ED-7”, processing conditions: rotation speed 15,000 rpm × Dispersed by centrifugation for 5 minutes, and centrifuged (manufactured by Kubota Shoji Co., Ltd., trade name “type 6800 centrifuge”, rotor type RA-400, treatment conditions: supernatant for 10 minutes at a centrifugal force of 39,200 m ² / s The supernatant was further centrifuged at 116000 m ² / s for 45 minutes. A volume obtained by a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., trade name “LA-910”, ultrasonication for 1 minute, refractive index 1.20) using the supernatant after centrifugation The integrated 50% particle diameter (volume average particle diameter) in the frequency particle size distribution was measured, and this value was defined as the average diameter.

<Dispersion medium content in cellulose aggregate>
The cellulose aggregate was dried for 5 hours with a vacuum dryer set at 120 ° C., and the dispersion medium content was calculated from the weight change before and after the drying.

<Particle diameter of cellulose aggregate>
The cellulose aggregate obtained in the second step is diluted in water so that the cellulose concentration is 0.5% by mass or less, and a laser diffraction particle size distribution measuring apparatus (SALD-2300: manufactured by Shimadzu Corporation) is used. It measured by refractive index 1.20.

<Cellulose aggregate content rate in resin composition (as a molding)>
After injection molding of the resin composition pellet into the shape of a multipurpose test piece of ISO, the central portion of the molded piece is subjected to an X-ray tube voltage of 40 kV using a high resolution 3DX line microscope (nano3DX: manufactured by Rigaku Corporation) CT measurement was performed for a current of 30 mA and 600 cubic μm at the center of the formed piece. The number of projections was 1000 and the exposure time was 24 seconds per sheet. The obtained data was binarized by the Otsu method, and the volume detected as an object in the composition was divided by the total volume to calculate the cellulose aggregate content in the molded product. In this case, if 10% by volume of cellulose is mixed and half of the cellulose is present as an aggregate of 1 μm or more in the composition, 5% by volume is the cellulose aggregate content.

<Ball-on-disk friction coefficient>
Using the grip portion of a molded piece injection-molded in the shape of a multipurpose test piece of ISO as a disk portion, the ball-on-disk friction coefficient sliding property to SUS was evaluated. Specifically, using a ball-on-disk type reciprocating friction and abrasion tester (AFT-15MS, manufactured by Toyo Seimitsu Co., Ltd.), under an environment of 23 ° C. and 50% humidity, a load of 9.8 N, linear velocity The sliding test was carried out 5000 times of reciprocation at a distance of 30 mm / sec and a reciprocation distance of 20 mm. At this time, the initial dynamic friction coefficient from the 10th sliding to the 100th sliding and the dynamic friction coefficient from the 4500th sliding to the 5000th sliding were determined. As a ball material, a SUS ball having a diameter of 5 mm was used.

<Rubbing noise of moldings>
The following evaluation criteria evaluated the generation | occurrence | production condition of the scaber noise which arises at the time of a ball on disc friction test.
++: The rubbing noise hardly occurs until the last (5000 slidings). +: The initial (less than about 100 slidings) the rubbing sounds but does not come back.
-: There is always a rattling noise, and wear can be seen.
−−: Always make a rattling noise, severe wear, and a large amount of wear powder

«Composition of extruder»
The cylinder 1 of a twin-screw extruder (STEER OMEGA 30H, L / D = 60) with 13 cylinder blocks is water-cooled, cylinder 2 is set at 80 ° C, cylinder 3 at 150 ° C, cylinder 4 to die at 250 ° C did.

  As screw configuration, it is assumed that cylinders 1 to 3 are conveyance zones constituted only by conveyance screws, and two clockwise kneading disks (feed type kneading disks from the upstream side of cylinder 4 are simply referred to as RKD hereinafter). There are 2) neutral kneading discs (non-conveying type kneading discs: hereinafter sometimes referred to simply as NKD) arranged in order. The cylinder 5 was a transfer zone, one RKD and two subsequent NKDs were disposed in the cylinder 6, the cylinders 7 and 8 were transfer zones, and two NKD were disposed in the cylinder 9. The following cylinder 10 was the transport zone, with two NKDs on cylinder 11 followed by one counterclockwise screw, and cylinders 12 and 13 as transport zones. In addition, the vent port was installed in the cylinder 12 upper part of the cylinder 12 so that decompression suction was possible, and vacuum suction was implemented.

Example 1
<< Step 1 >> Preparation of Cellulose Fiber-Containing Mixture After cutting the linter pulp, it is heated in hot water of 120 ° C. or more for 3 hours using an autoclave to squeeze the purified pulp from which the hemicellulose part has been removed, into pure water After being highly shortened and fibrillated by beating so as to have a solid content of 1.5% by weight, disaggregate it with a high-pressure homogenizer (operating pressure: treated 10 times at 85 MPa) at the same concentration Thus, disintegrated cellulose was obtained. Here, in the beating process, a disc refiner is used, and after processing for 4 hours with a beating blade having a high cutting function (hereinafter referred to as a cutting blade), using a beating blade having a high disintegration function (hereinafter referred to as a disintegration blade) The beating was carried out for another 1.5 hours to obtain a cellulose fiber. The properties of the obtained cellulose fiber were evaluated by the method described above. The results are shown below.
L / D = 300
Average fiber diameter = 90 nm
Crystallinity = 80%
Degree of polymerization = 600
The obtained cellulose fiber dispersion was subjected to centrifugal filtration to obtain a mixture having a solid content (cellulose) ratio of 5% by weight.

<< Step 2 >> A step of stirring while heating the cellulose-containing mixture to remove the dispersion medium to obtain a cellulose aggregate The cellulose-containing mixture of step 1 is a closed planetary mixer (manufactured by Kodaira Seisakusho, trade name “ACM- Stirring process is performed at 25 rpm and atmospheric pressure for 80 minutes at 70 rpm in a hook type), and then the 60 ° C. water bath is set under reduced pressure conditions of −0.1 MPa, and decompressed for 5 hours at 307 rpm. Drying treatment was performed to obtain a cellulose aggregate. The water content of the cellulose aggregate at this time and the particle diameter of the cellulose aggregate were measured according to the above-mentioned method.

<< Step 3 >> Step of Kneading Cellulose Aggregate and Thermoplastic Resin PA and Cellulose Aggregate were mixed in proportions as shown in Table 1, melt-kneaded, extruded in strands, water-cooled and cut, and obtained as pellets .

Example 2
The same procedure as in Example 1 was carried out except that step 1 was changed as follows.
<< Step 1 >> Preparation of Cellulose Whisker-Containing Mixture A commercially available DP pulp (average degree of polymerization: 1600) was cut and hydrolyzed in a 10% aqueous hydrochloric acid solution at 105 ° C. for 30 minutes. The obtained acid insoluble residue was filtered, washed and pH-adjusted to prepare a cellulose whisker-containing mixture having a solid concentration of 14% by weight and a pH of 6.5. The properties of the obtained cellulose whiskers were evaluated by the method described above. The results are shown below.
L / D = 1.6
Average diameter = 200 nm
Crystallinity = 78%
Degree of polymerization = 200

[Example 3]
The same procedure as in Example 1 was carried out except that step 1 was changed as follows.
<< Step 1 >> Preparation of Cellulose-Containing Mixture The cellulose fiber-containing mixture obtained in Step 1 of Example 1 and the cellulose whisker-containing mixture obtained in Step 1 of Example 2 are the cellulose fibers and cellulose whiskers in the mixture. A cellulose-containing mixture containing cellulose fibers and cellulose whiskers was prepared by mixing with a stirrer such that the ratio of

Example 4
The same procedure as in Example 1 was carried out except that step 1 was changed as follows.
<< Step 1 >> Preparation of Cellulose Whisker Surfactant-Containing Mixture With respect to 100 parts by mass of the cellulose whisker in the cellulose whisker-containing mixture obtained in Step 1 of Example 2, a polyoxy acid as a surfactant other than water is used. Twenty-five parts by mass of ethylene-cured castor oil ether (Brownone RCW-20 manufactured by Aoki Yushi Kogyo Co., Ltd.) was added and stirred to prepare a cellulose whisker surfactant-containing mixture. The properties of the cellulose whiskers are the same as in Example 2.

[Example 5]
Among the conditions in the step 2, the same procedure as in Example 3 was carried out except that the drying time of the reduced-pressure drying was 3 hours.

[Example 6]
Among the conditions in the step 2, the process was carried out in the same manner as in Example 3 except that the temperature condition of the reduced-pressure drying process was 75 ° C.

[Example 7]
Among the conditions in Step 2, the same procedure as in Example 3 was carried out except that the number of revolutions of the planetary mixer in the reduced-pressure drying was 170 rpm.

[Example 8]
Among the conditions in Step 2, the same procedure as in Example 3 was carried out except that the number of revolutions of the planetary mixer in the reduced-pressure drying was 70 rpm.

Comparative Example 1
Among the conditions in the step 2, the same procedure as in Example 3 was carried out except that the time of reduced pressure drying was changed to 1 hour.

Comparative Example 2
Among the conditions in Step 2, the same procedure as in Example 3 was performed except that the temperature condition of the reduced-pressure drying treatment was 95 ° C.

Comparative Example 3
The cellulose aggregate obtained in Step 2 was carried out in the same manner as Example 3 except that the cellulose aggregate was stored for 96 hours under an environment of 23 ° C. and humidity 70% RH.

  In the second step, various conditions of stirring and drying are selected, and the dispersion medium content of the cellulose aggregate is optimized, thereby forming a cellulose aggregate having an optimum diameter in the molded product. It can be seen that indicates excellent sliding characteristics. On the other hand, in the comparative example in which the stirring and drying conditions are not suitable and the dispersion medium content does not reach an appropriate value, as a result, the dispersed particle diameter of cellulose and the aggregate content become unsuitable. The result is that the slidability is greatly reduced.

  The resin composition obtained by the production method of the present invention can be suitably applied to molded articles of various applications such as automobile parts, electric / electronic parts, office equipment housings, precision parts and the like.

Example 1 (Reference Example)
<< Step 1 >> Preparation of Cellulose Fiber-Containing Mixture After cutting the linter pulp, it is heated in hot water of 120 ° C. or more for 3 hours using an autoclave to squeeze the purified pulp from which the hemicellulose part has been removed, into pure water After being highly shortened and fibrillated by beating so as to have a solid content of 1.5% by weight, disaggregate it with a high-pressure homogenizer (operating pressure: treated 10 times at 85 MPa) at the same concentration Thus, disintegrated cellulose was obtained. Here, in the beating process, a disc refiner is used, and after processing for 4 hours with a beating blade having a high cutting function (hereinafter referred to as a cutting blade), using a beating blade having a high disintegration function (hereinafter referred to as a disintegration blade) The beating was carried out for another 1.5 hours to obtain a cellulose fiber. The properties of the obtained cellulose fiber were evaluated by the method described above. The results are shown below.
L / D = 300
Average fiber diameter = 90 nm
Crystallinity = 80%
Degree of polymerization = 600
The obtained cellulose fiber dispersion was subjected to centrifugal filtration to obtain a mixture having a solid content (cellulose) ratio of 5% by weight.

Example 2 (Reference Example)
The same procedure as in Example 1 was carried out except that step 1 was changed as follows.
<< Step 1 >> Preparation of Cellulose Whisker-Containing Mixture A commercially available DP pulp (average degree of polymerization: 1600) was cut and hydrolyzed in a 10% aqueous hydrochloric acid solution at 105 ° C. for 30 minutes. The obtained acid insoluble residue was filtered, washed and pH-adjusted to prepare a cellulose whisker-containing mixture having a solid concentration of 14% by weight and a pH of 6.5. The properties of the obtained cellulose whiskers were evaluated by the method described above. The results are shown below.
L / D = 1.6
Average diameter = 200 nm
Crystallinity = 78%
Degree of polymerization = 200

Example 4 (Reference Example)
The same procedure as in Example 1 was carried out except that step 1 was changed as follows.
<< Step 1 >> Preparation of Cellulose Whisker Surfactant-Containing Mixture With respect to 100 parts by mass of the cellulose whisker in the cellulose whisker-containing mixture obtained in Step 1 of Example 2, a polyoxy acid as a surfactant other than water is used. Twenty-five parts by mass of ethylene-cured castor oil ether (Brownone RCW-20 manufactured by Aoki Yushi Kogyo Co., Ltd.) was added and stirred to prepare a cellulose whisker surfactant-containing mixture. The properties of the cellulose whiskers are the same as in Example 2.

Claims (7)

A method of producing a resin composition comprising a thermoplastic resin and cellulose,
A first step of preparing a mixture containing a dispersion medium containing water as a main component and cellulose dispersed in the dispersion medium,
A second step of stirring the mixture while heating and removing the dispersion medium to obtain a cellulose aggregate; and a third step of kneading the cellulose aggregate obtained in the second step and the thermoplastic resin,
In this order,
The manufacturing method of the resin composition whose ratio of the dispersion medium contained in the cellulose aggregate obtained at 2nd process is 0.1-10 mass%.   The manufacturing method of the resin composition of Claim 1 whose cellulose is a cellulose fiber, a cellulose whisker, or these mixtures.   The manufacturing method of the resin composition of Claim 1 or 2 whose average particle diameter of a cellulose aggregate is 0.1-100 micrometers.   The manufacturing method of the resin composition as described in any one of Claims 1-3 whose ratio of the cellulose contained in the mixture obtained at a 1st process is 1-30 mass%.   The resin composition according to any one of claims 1 to 4, wherein the second step is carried out by any one selected from a single-screw extruder, a twin-screw extruder, a kneader, a planetary mixer, and a lycaing machine. Manufacturing method.   The method for producing a resin composition according to any one of claims 1 to 5, wherein at least a part of the third step is carried out under reduced pressure less than atmospheric pressure.   The manufacturing method of the resin composition as described in any one of Claims 1-6 whose volume ratio of a cellulose aggregate with a diameter of 1 micrometer or more is 0.1-50 volume% with respect to 100 volume% of resin compositions. .