JP2017122177A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which is comparatively inexpensive, does not cause a problem of thermal recycling, a problem of a solvent treatment and the like, and has a strong strength, and a method for producing the thermoplastic resin composition.SOLUTION: A thermoplastic resin composition contains a cellulose nanofiber having a standard deviation (σ) of an average fiber diameter of 20 nm or less and a compatibilizer, and has a peak value in pseudo particle size distribution curve of an aqueous dispersion of a cellulose nanofiber of 5-25 μm, a half value width of a peak of 15 μm or less, a bending strength according to JIS K7171:2008 of 1.10 times or more, and a retention of tensile elongation at break in tensile strength test according to JIS K7161:2014 of 70% or more, when compared to a blank product containing no cellulose nanofiber and compatibilizer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermoplastic resin composition.

  Conventionally, carbon fiber or glass fiber has been used as a reinforcing material for thermoplastic resin. However, carbon fibers are not suitable for thermal recycling because they are difficult to burn, and have a problem of high price. Glass fibers also have a disposal problem in thermal recycling. Furthermore, although carbon fiber and glass fiber are rigid, they are brittle materials with a small elongation until breakage, and when combined with a resin, the mechanical strength increases, but the ductility of the thermoplastic resin is lost. Have a side.

  Therefore, in recent years, research has been conducted on a technique for using plant fibers, which are relatively inexpensive and have no thermal recycling problem, as a reinforcing material for thermoplastic resins. Plant fiber is not used by being artificially synthesized into a fiber like carbon fiber or glass fiber, but is used by loosening the fine fiber structural unit of the plant structure, so it is inexpensive and reinforced The effect is also excellent. As for the problem of thermal recycling, carbon fiber and glass fiber remain as ash during incineration, causing problems such as blockage of furnace piping and landfill treatment by ash, while plant fiber remains almost as ash. Therefore, problems such as blockage of furnace piping and landfill treatment do not occur.

  At present, proposals have been made to use cellulose nanofibers obtained by refining plant fibers as a reinforcing material for thermoplastic resins. The thermoplastic resin composition using the cellulose nanofibers as a reinforcing material is said to be as light as 1/5 of steel and have the same strength.

  However, when cellulose nanofibers are used as a reinforcing material, the cellulose nanofibers are mixed with a thermoplastic resin as a dispersion. However, when the moisture of cellulose nanofibers mixed with the thermoplastic resin is removed, the cellulose nanofibers are mixed. The fibers aggregate irreversibly due to intermolecular hydrogen bonds derived from the hydroxyl groups of the polysaccharide. Therefore, even if cellulose nanofiber is used as a reinforcing material, the reinforcing effect of the thermoplastic resin is not sufficiently exhibited due to the poor dispersibility of the cellulose nanofiber in the thermoplastic resin. There is a problem that ductility is lowered.

  Thus, for example, Patent Documents 1 to 3 disclose techniques for surface modification of cellulose microfibrils. However, the surface modifier has a problem of being deactivated in water. In addition, since the reaction is very slow in water, it must be treated in an organic solvent, resulting in a solvent treatment problem. That is, when an organic solvent is used, it is necessary to take measures to prevent the organic solvent from being scattered in the atmosphere in each step, to newly install a solvent treatment facility, and to increase manufacturing costs.

  Patent Document 4 discloses a technique for drying and classifying cellulose fibers prior to kneading with a thermoplastic resin. However, since the cellulose fiber itself is hydrophilic, the bondability at the interface with the thermoplastic resin, which is hydrophobic, is poor, resulting in a problem in dispersibility, which can solve the problem of the reinforcing effect caused by this. Can not.

  Furthermore, patent document 5 is disclosing the technique which uses apparatuses, such as a homogenizer, a stone mill type friction machine, and a refiner, in refining | pulverizing a pulp fiber. However, it has been found that even by this method, the uniformity of the reinforcing effect, particularly the reinforcing effect of the thermoplastic resin, is insufficient.

  Patent Document 6 discloses a technique in which bamboo pulp is defibrated only with a high-pressure water stream and fine fibers obtained by this defibration are combined with a thermoplastic resin so that the content becomes 10% by mass. The thermoplastic resin composition by this technique has a flexural modulus 1.2 times that of the original thermoplastic resin, and has a reinforcing effect over the thermoplastic resin composition obtained by similarly treating LBKP instead of bamboo pulp. Is said to be high. However, this technology is a problem of collection efficiency due to the low bulk specific gravity of bamboo pulp, chipper cutter blade wear faster than hardwood and coniferous wood when processing into chips, and a large amount generated during cooking Since it is difficult to pulp with a continuous digester due to blockage of the piping with silica, it is considered by those skilled in the art to produce with a batch digester, and there is a problem that productivity is significantly reduced, and supply due to limited bamboo production areas is not possible. Has the problem of becoming stable.

  On the other hand, Non-Patent Document 1 discloses a correlation between mechanical strength and ductility (elongation) when an inorganic filler is kneaded with a thermoplastic resin. This document shows a tendency that the smaller the aspect ratio of the inorganic filler (the value obtained by dividing the filler length by the filler width) is, the lower the mechanical strength of the thermoplastic resin is, but the higher the ductility of the thermoplastic resin is. ing.

JP 2012-229350 A JP 2012-214563 A Japanese National Patent Publication No. 11-513425 JP 2010-089483 A JP 2009-029927 A JP 2013-245346 A

Polymer 46 (2005) 6325-6334

  The main problem to be solved by the present invention is to provide a thermoplastic resin composition that is relatively inexpensive, does not cause problems of thermal recycling or solvent treatment, has high strength, and maintains ductility. is there. More preferably, it is to provide a thermoplastic resin composition suitable for a technical field in which high mechanical strength is an essential physical property while maintaining ductility of automobile interior materials and toys.

The present invention for solving the above problems is as follows.
(Means of Claim 1)
Cellulose nanofibers having a standard deviation (σ) of average fiber diameter of 20 nm or less, and a compatibilizer,
The peak value in the pseudo particle size distribution curve of the aqueous dispersion of cellulose nanofiber is 5 to 25 μm, and the half value width of the peak value is 15 μm or less,
When compared with a blank product that does not contain the cellulose nanofiber and the compatibilizer, the bending strength in accordance with JIS K7171: 2008 is 1.10 times or more,
In the tensile strength test based on JIS K7161: 2014, the retention of tensile elongation at break is 70% or more.
The thermoplastic resin composition characterized by the above-mentioned.
Here, the retention ratio of the tensile elongation at break is a value calculated by (tensile elongation at break of thermoplastic resin composition containing cellulose nanofiber and compatibilizing agent / tensile elongation at break of blank) × 100 (%). It is.

(Means according to claim 2)
The cellulose nanofiber has an average fiber diameter of 4 to 500 nm.
The thermoplastic resin composition according to claim 1.

(Means according to claim 3)
The cellulose nanofiber has a crystallinity of 50 to 90%.
The thermoplastic resin composition according to claim 1 or 2.

(Means according to claim 4)
The cellulose nanofiber has a water retention of 500% or less.
The thermoplastic resin composition according to claim 1.

(Means according to claim 5)
The cellulose nanofiber has one peak value and 5 μm or more.
The thermoplastic resin composition according to claim 1.

(Means according to claim 6)
The cellulose nanofiber has a pulp viscosity of 1.5 cps or more,
The thermoplastic resin composition according to claim 1.

(Means according to claim 7)
The thermoplastic resin composition according to claim 1, wherein the compatibilizing agent is a modified product containing at least one selected from maleic anhydride, itotanic anhydride, citraconic anhydride, and anhydrous citric acid. .

(Reference properties)
When the plant fiber used as the raw material is pulp fiber, the resulting thermoplastic resin composition can be made inexpensive and the problem of thermal recycling can be avoided. Moreover, it is not necessary to use a surface modifier that chemically modifies hydroxyl groups such as cellulose in an organic solvent, and the problem of solvent treatment can be avoided.

  Cellulose nanofibers obtained from pulp fibers are fine and have a large specific surface area, have many hydroxyl groups on the surface, and are hydrophilic. Accordingly, the drainage and dewaterability are poor, the bondability with a thermoplastic resin that is inherently hydrophobic is poor, and the reinforcing effect, particularly the mechanical strength such as bending strength, tends to be inferior. However, when pulp fibers are refined to make cellulose nanofibers, if the refinement treatment is defibrated with a water stream, particularly a high-pressure water stream (preferably the pulp fibers are unwound to a predetermined width), the water retention of cellulose nanofibers The degree can be kept low, and the bondability with the thermoplastic resin can be improved.

  In addition, the present inventors, for hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), a method other than the process of defibrating with a water stream, specifically, a processing method of defibrating using a grinder The water retention of the fiber after this refinement treatment was examined. As a result, it was found that the water retention level significantly increased with the miniaturization treatment.

  However, the fiber (cellulose nanofiber) simply refined is entangled with each other during kneading with the thermoplastic resin, and there remains a problem that the reinforcing effect is not sufficiently exhibited. However, if the pulp fibers are beaten prior to the miniaturization treatment and are cut so that the average fiber lengths are uniform, particularly the predetermined fiber lengths, the fibers are less likely to aggregate.

  In addition, when water retention is low, drainage, dehydration, drying, dispersibility in a thermoplastic resin, etc. will improve. As a result, the strength of the thermoplastic resin composition is also improved. Further, when the dehydrating property is improved, for example, energy when kneading cellulose nanofibers and a thermoplastic resin to dehydrate can be reduced, which is advantageous in terms of manufacturing cost.

  However, if the above-mentioned refinement treatment is performed until the average fiber diameter is less than 4 nm, the production cost increases, and therefore, it is preferable to perform the refinement treatment in a range where the average fiber diameter is 4 nm or more. Further, when the refinement treatment is performed until the average fiber diameter becomes 500 nm or less, the dehydrating property is improved, and the mechanical strength such as the bending strength and tensile elastic modulus of the obtained thermoplastic resin composition is improved.

  The inventors of the present invention made cellulose nanofibers (average fiber diameter of 500 nm or less) obtained by refining hardwood bleached kraft pulp (LBKP) (average fiber diameter of 10 to 50 μm) and hardwood bleached kraft pulp (LBKP). A test of kneading was performed after drying by applying heat instead of the powder of thermoplastic resin (PP and MAPP) and the masterbatch method and solid phase shearing method described later. As a result, the bending strength and tensile strength of the obtained thermoplastic resin composition tended to be “hardwood bleached kraft pulp (LBKP)” <“cellulose nanofiber”.

  When the degree of crystallinity of the cellulose nanofiber is less than 50%, there is no problem in compatibility with the thermoplastic resin, but the strength of the fiber itself is lowered, so the strength of the thermoplastic resin composition tends to be inferior. On the other hand, when the crystallinity of the cellulose nanofiber exceeds 90%, the ratio of strong hydrogen bonds in the molecule increases and the fiber itself becomes stiff, but the compatibility with the thermoplastic resin decreases, and the thermoplastic resin composition The strength of the object tends to be inferior.

  That the peak value in the pseudo particle size distribution curve of cellulose nanofiber is one peak means that the uniformity of the fiber length and the fiber diameter is high, and drying and dispersion proceed uniformly. Moreover, when the uniformity of fiber diameter and fiber length is high, the reinforcing effect of the thermoplastic resin composition is strong, and the uniformity of the reinforcing effect is also improved.

  In order to make the peak value of the cellulose nanofibers less than 5 μm, it is necessary to carry out a fine treatment for a long time, which leads to an increase in production cost. On the other hand, if the peak value exceeds 25 μm, the refinement process is insufficient and the uniformity of the fiber diameter and fiber length tends to be inferior.

  When the enzyme treatment, acid treatment, or oxidation treatment is performed prior to or simultaneously with the beating treatment in the pretreatment, the water retention of the cellulose nanofibers can be lowered, the crystallinity can be increased, and the homogeneity can be increased. it can. In this regard, the lower the water retention of cellulose nanofibers, the better the dispersibility in thermoplastic resins, and the higher the homogeneity of cellulose nanofibers, the fewer defects that cause destruction of the thermoplastic resin composition. It is considered that a thermoplastic resin composition having a high strength capable of maintaining the ductility of the thermoplastic resin can be obtained.

  When a filler-like reinforcing material is blended with a thermoplastic resin, it is known that the greater the aspect ratio, the higher the mechanical strength reinforcing effect and the lower the ductility (elongation). However, when cellulose nanofibers obtained from pulp fibers are used as a reinforcing material, it is considered that defects that cause destruction of the thermoplastic resin composition are reduced by increasing the homogeneity of the fibers. It is possible to offset the reduction of the reinforcing effect.

  Specifically, the peak value in the pseudo particle size distribution curve of the aqueous dispersion of cellulose nanofiber is 5 to 25 μm, the half width of the peak is 15 μm or less, and the standard deviation value of the average fiber diameter of the cellulose nanofiber is 20 nm. When it is below, a thermoplastic resin composition having high mechanical strength and minimal reduction in ductility (elongation) even when the aspect ratio of the cellulose nanofiber is small can be obtained.

  In addition, the hemicellulose and cellulose amorphous regions of the pulp are decomposed by enzyme treatment, acid treatment, and oxidation treatment. As a result, energy of beating treatment and subsequent refinement treatment can be reduced, and fiber homogeneity and Dispersibility can be improved. Moreover, when the proportion of the cellulose crystal region, which is thought to be rigid and low in water retention, in the molecular chain is increased, the dispersibility improves and the aspect ratio decreases, but the ductility is maintained. A thermoplastic resin composition having high mechanical strength can be obtained.

  In addition, by performing alkali treatment, hemicellulose and cellulose hydroxyl groups of the pulp are partially dissociated, and the molecules are anionized to weaken intramolecular and intermolecular hydrogen bonds, facilitating the dispersion of cellulose nanofibers in the beating process. There is an effect to. As alkali, organic alkali such as sodium hydroxide, lithium hydroxide, potassium hydroxide, aqueous ammonia solution, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, etc. are used. However, it is preferable to use sodium hydroxide from the viewpoint of production cost.

  According to the present invention, a thermoplastic resin composition that is relatively inexpensive, does not cause problems of thermal recycling, solvent processing, and the like, has high strength, and maintains ductility.

It is a flowchart of the manufacturing process of a thermoplastic resin composition.

Next, modes for carrying out the invention will be described.
The thermoplastic resin composition of this embodiment contains a thermoplastic resin and cellulose nanofibers that are plant fibers, and further has a compatibilizing agent added thereto.

(Pulp fiber)
Cellulose nanofibers can be obtained by refining (defibrating) pulp fibers. As a fiber used as a raw material, one type or two or more types can be selected and used from plant-derived fibers, animal-derived fibers, microorganism-derived fibers, and the like. However, it is preferable to use at least pulp fibers which are plant fibers.

  The plant-derived fibers include 1 of wood pulp made from hardwood, conifer, etc., non-wood pulp made from straw, bagasse, etc., recovered paper, waste paper pulp made from waste paper, etc. (DIP) Species or two or more can be selected and used.

  As wood pulp, use one or more selected from chemical pulp such as hardwood kraft pulp (LKP), softwood kraft pulp (NKP), mechanical pulp (TMP), and waste paper pulp (DIP). Can do. These pulps are pulps used in papermaking applications, and existing facilities can be effectively utilized by using these pulps.

  The hardwood kraft pulp (LKP) may be hardwood bleached kraft pulp, hardwood unbleached kraft pulp, or hardwood semi-bleached kraft pulp. Similarly, softwood kraft pulp (NKP) may be softwood bleached kraft pulp, softwood unbleached kraft pulp, or softwood semi-bleached kraft pulp.

  Further, the waste paper pulp (DIP) may be magazine waste paper pulp (MDIP), newspaper waste paper pulp (NDIP), corrugated waste paper pulp (WP), or other waste paper pulp. Good.

  Furthermore, as the mechanical pulp, for example, stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), chemi-ground pulp (CGP), thermo grand pulp (TGP), ground pulp (GP) ), Thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP), bleached thermomechanical pulp (BTMP) and the like can be selected and used. .

(Pretreatment process)
The pulp fibers are preferably pretreated by physical or chemical techniques, preferably by physical and chemical techniques. By performing the pre-processing by a physical method or a chemical method prior to the miniaturization process, the number of the miniaturization processes can be greatly reduced, and the energy of the miniaturization process can be greatly reduced.

  As pre-processing by a physical method, beating processing is preferable. When the pulp fibers are beaten, the pulp fibers are cut out, and the problem that the fibers are entangled and aggregated during kneading with the thermoplastic resin is solved.

  This beating treatment is preferably performed until the freeness of the pulp fiber is 120 ml or less, more preferably 110 ml or less, and particularly preferably 100 ml or less.

  The beating process can be performed using, for example, a refiner or a beater.

  Pretreatment by chemical method includes hydrolysis of polysaccharide with acid (acid treatment), hydrolysis of polysaccharide with enzyme (enzyme treatment), swelling of polysaccharide with alkali (alkali treatment), oxidation of polysaccharide with oxidizing agent (oxidation treatment) ), Reduction of polysaccharides with a reducing agent (reduction treatment), and the like.

  However, the enzyme treatment is preferably performed, and in addition, it is more preferable to perform one or more treatments selected from acid treatment, alkali treatment, and oxidation treatment.

Here, the enzyme treatment will be described in detail.
The enzyme treatment is performed in order to make the cellulosic fiber finer. As the enzyme, it is preferable to use at least one of a cellulase enzyme and a hemicellulase enzyme, and it is more preferable to use both in combination.

  Cellulase-based enzymes are enzymes that cause degradation of cellulose in the presence of water.

  Cellulase-based enzymes include the genus Trichoderma, the genus Acremonium, the genus Aspergillus, the genus Phanerochaete, the trametes, Trametes, Genus, Humicola (filamentous fungus) genus, Bacillus (bacteria) genus, Suehirotake (basidiomycete) genus, Streptomyces (bacteria) genus, Pseudomonas (bacteria) genus, etc. Can be illustrated.

  These cellulase enzymes can be purchased as reagents or commercial products. For example, cellulosin T2 (manufactured by HIPI), Meiserose (manufactured by Meiji Seika), Novozyme 188 (manufactured by Novozyme), multifect CX10L (manufactured by Genencor), cellulase enzyme GC220 (manufactured by Genencor), etc. can do.

  Of these cellulase enzymes, filamentous fungal cellulase enzymes are preferred, and among filamentous fungal cellulase enzymes, cellulase enzymes produced by Trichoderma bacterium (Trichoderma reesei or Hyporea jerorina, a type of filamentous fungus) are preferred. These cellulase enzymes are abundant in variety and highly productive.

  Cellulase enzymes are classified into a carbohydrate hydrolase family (GH family) based on a higher-order structure of a catalytic domain having a hydrolysis reaction function. Cellulase enzymes are classified into endo-glucanase (EG) and cellobiohydrolase (CBH) according to cellulose degradation characteristics.

  EG is highly hydrolyzable to cellulose non-crystalline parts, soluble cellooligosaccharides, and cellulose derivatives such as carboxymethylcellulose, and these molecular chains are randomly cleaved from the inside to lower the degree of polymerization but have crystallinity. Low reactivity with cellulose microfibrils.

  On the other hand, CBH also decomposes the crystalline part of cellulose to give cellobiose. CBH is hydrolyzed from the end of the cellulose molecule and is also called an exo-type or processive enzyme. EG is also called a non-processive enzyme.

  In this embodiment, both EG and CBH can be used as the cellulase enzyme. Each may be used alone, or EG and CBH may be mixed and used. Moreover, you may mix and use a hemicellulase type enzyme. The crystallinity of the cellulose nanofiber can be adjusted by suitably combining EG and CBH.

  A hemicellulase-based enzyme is an enzyme that causes the decomposition of hemicellulose in the presence of water.

  Examples of hemicellulase enzymes include xylanase, which is an enzyme that degrades xylan, mannase, which is an enzyme that degrades mannan, and arabanase, which is an enzyme that degrades araban. In addition, pectinase, which is an enzyme that degrades pectin, can also be used as a hemicellulose enzyme. Microorganisms that produce hemicellulase enzymes often also produce cellulase enzymes.

  Hemicellulose is a polysaccharide excluding pectins between cellulose microfibrils in the plant cell wall. Hemicellulose is diverse and varies between wood types and cell wall layers. In the secondary wall of conifers, glucomannan is the main component, and in the secondary wall of hardwoods, 4-O-methylglucuronoxylan is the main component. Therefore, it is preferable to use mannase to obtain fine fibrous cellulose from softwood bleached kraft pulp (NBKP), and in the case of hardwood bleached kraft pulp (LBKP), it is preferable to use xylanase.

  The amount of enzyme added to the pulp is not particularly limited, and can be appropriately adjusted depending on the type of enzyme, the type of wood (coniferous or hardwood), the type of mechanical pulp, and the like. However, the enzyme is preferably added in an amount of 0.1% to 3% by weight, more preferably 0.3% to 2.5% by weight, more preferably 0.5% to It is particularly preferable to add 2% by weight. If the addition amount is less than 0.1% by mass, the effect of the enzyme may be reduced. On the other hand, if the addition amount exceeds 3% by mass, cellulose may be saccharified and the yield of fine fibers may be reduced, and even if added excessively, no improvement in the effect commensurate with the increase in addition amount is observed. .

  The pH of the pulp during the cellulase enzyme treatment is preferably a weakly acidic region (pH = 3.0 to 6.9) from the viewpoint of the reactivity of the enzyme reaction. On the other hand, the pH of the pulp during the hemicellulase-based enzyme treatment is preferably in a weakly alkaline region (pH = 7.1 to 10.0).

  The temperature during the enzyme treatment is not particularly limited, but the temperature during the treatment of the cellulase enzyme or hemicellulase enzyme is preferably 30 ° C to 70 ° C, and preferably 35 ° C to 65 ° C. More preferably, it is 40 to 60 degreeC. If the temperature during the enzyme treatment is equal to or higher than the lower limit, the enzyme activity is unlikely to decrease and the treatment time can be prevented from prolonging. Moreover, if it is below an upper limit, inactivation of an enzyme can be prevented.

  The enzyme treatment time can be adjusted by the kind of enzyme, temperature, pH and the like. The enzyme treatment time is preferably 0.5 to 24 hours. If the treatment time is less than 0.5 hours, the effect of the enzyme treatment may hardly be obtained. When it is 24 hours or less, shortening of the fiber length due to decomposition of the cellulose fiber by the enzyme can be suppressed, and the effect of improving the strength when blended in the resin can be sufficiently obtained.

  It is preferable to deactivate the enzyme after the enzyme treatment. If the enzyme is not deactivated, the enzymatic reaction proceeds and the saccharification of the fiber progresses, resulting in a decrease in yield and the fiber length becoming too short.

  Examples of the method for inactivating the enzyme include a method of adding an alkaline aqueous solution (preferably pH 10 or more, more preferably pH 11 or more) and a method of adding hot water at 80 to 100 ° C.

  In addition to the above, examples of the pretreatment include chemical treatment such as phosphate esterification treatment, acetylation treatment, and cyanoethylation treatment.

  The physical treatment and the chemical treatment can be performed simultaneously or separately.

(Miniaturization process)
The pulp fiber is subjected to a pretreatment such as a beating process and then a refinement (defibration) process. By this refinement treatment, the pulp fibers are microfibrillated to become cellulose nanofibers.

  The refinement process is performed by, for example, one or more of a high-pressure homogenizer, a homogenizer such as a high-pressure homogenizer, a stone mill type friction machine such as a grinder or an attritor, a refiner such as a conical refiner or a disc refiner, or various bacteria. It is conceivable to carry out by selecting and using these means.

  However, in this embodiment, it is carried out by using an apparatus / method for refining with a water stream, particularly a high-pressure water stream. According to this apparatus and method, the dimensional uniformity and dispersion uniformity of the cellulose nanofibers are very high, and the strength of the finally obtained thermoplastic resin, particularly the bending strength, is high.

  In this regard, for example, if a grinder that grinds between rotating grindstones is used, it is difficult to uniformly refine the fiber, and a fiber lump that cannot be partially separated remains, and the thermoplastic resin composition finally obtained There is a risk that the strength of the object becomes uneven. Therefore, in particular, in a molded product of a thermoplastic resin composition having a small thickness, there is a possibility that poor molding and insufficient strength may occur.

  In addition, as a grinder, for example, there is a mass collider of Masuko Sangyo Co., Ltd. Moreover, as an apparatus which refines | miniaturizes with a high-pressure water flow, there exists Starburst (registered trademark) of Sugino Machine Co., Ltd., Nanovaita \ Nanovater (registered trademark) of Yoshida Machine Industry Co., Ltd., etc., for example.

  The inventors of the present invention conducted a test of refining pulp fibers and observing each of the obtained fibers with a method of grinding between rotating grindstones and a method of refining with a high-pressure water stream. As a result, the fibers obtained by the method of refining with a high-pressure water stream had a uniform fiber width. Therefore, it was found that the reinforcement effect is more evenly exhibited by using the fiber obtained by the method of refining with a high-pressure water stream when the composite to the thermoplastic resin is assumed.

Here, the defibrating process using the high-pressure water flow will be described in detail.
For defibration by high-pressure water flow, the pulp dispersion is pressurized to 30 MPa or more, preferably 100 MPa or more, more preferably 150 MPa or more, particularly preferably 220 MPa or more with a pressure intensifier, and ejected from a nozzle having a pore diameter of 50 μm or more, It is preferable to perform the pressure reduction so that the pressure difference is, for example, 30 MPa or more, preferably 80 MPa or more, more preferably 90 MPa or more. The pulp raw material is defibrated by the cleavage phenomenon caused by this pressure difference. When the pressure under the high pressure condition is low or when the pressure difference from the high pressure to the decompression condition is small, the defibrating efficiency may be reduced, and a large number of repeated ejections may be required to obtain a desired fiber diameter.

  A high-pressure homogenizer is preferable as an apparatus for performing defibration with a high-pressure water stream. The high-pressure homogenizer is a homogenizer having the ability to discharge slurry at a pressure of, for example, 10 MPa or more, preferably 100 MPa or more. By treating the pulp fibers with a high-pressure homogenizer, collision between the pulp fibers, a pressure difference, microcavitation, and the like act, and defibration occurs effectively. Thereby, the processing frequency of a refinement | miniaturization process can be reduced (shortening) and the manufacturing efficiency of a cellulose nanofiber can be improved more.

  When the pulp fiber is sufficiently softened by passing through the pretreatment step, the pulp fiber is treated with a high-pressure homogenizer, and collisions between the pulp fibers act on the pulp fiber, thereby effectively releasing the fiber. Thereby, the processing frequency of a refinement | miniaturization process can be reduced more and the productivity of a cellulose nanofiber can be improved more.

  As a high-pressure homogenizer, it is preferable that the slurry collide oppositely on a straight line. Specifically, for example, in an opposed collision type high-pressure homogenizer (microfluidizer / MICROFLUIDIZER (registered trademark), wet jet mill) which is an example of this, two such that pressurized slurry collides oppositely at a junction. The upstream flow path is formed. The slurry collides at the junction, and the collided slurry flows out from the downstream channel. The downstream channel is provided perpendicular to the upstream channel, and the upstream channel and the downstream channel form a T-shaped channel. By using such an opposing collision type high-pressure homogenizer, energy given from the high-pressure homogenizer can be converted to collision energy to the maximum, and more efficient pulp fiber defibration occurs.

  The above-mentioned refinement treatment is, for example, the average fiber diameter, water retention, crystallinity, peak value of pseudo particle size distribution, tentacle test results, pulp viscosity, and the like of the obtained cellulose nanofibers are desired values or evaluations. It is preferable to do so.

  Cellulose nanofibers are fibers made of cellulose or cellulose derivatives. Ordinary cellulose nanofibers have strong hydration properties, and stably maintain a dispersed state (dispersion state) by hydrating in an aqueous medium. The single fiber constituting the cellulose nanofiber may be formed into a fibrous shape by collecting a plurality of filaments in an aqueous medium. The average fiber diameter (average diameter of single fibers) of normal cellulose nanofibers is 4 to 2,000 nm. The average fiber length is 1 to 5,000 μm.

(Average fiber diameter)
The average fiber diameter (average diameter of single fibers) of the cellulose nanofiber is preferably 4 to 500 nm, more preferably 6 to 450 nm, and particularly preferably 10 to 400 nm. When the average fiber diameter is 4 to 500 nm, the compatibility with the thermoplastic resin and the reinforcing effect of the thermoplastic resin composition are excellent.

  Specifically, when the average fiber diameter is less than 4 nm, excessive mechanical energy is applied to the pulp fiber, and the strength of the fiber itself decreases. As a result, there is a tendency that the reinforcing effect of the thermoplastic resin composition is inferior. In addition, the time for the miniaturization process becomes longer, leading to an increase in manufacturing cost. On the other hand, when the average fiber diameter exceeds 500 nm, the fineness is insufficient and the dispersibility of the fibers tends to be inferior. If the dispersibility of the fibers is insufficient, the reinforcing effect of the thermoplastic resin composition tends to be inferior.

  In this embodiment, a single fiber having a diameter of more than 500 μm may be contained, but the ratio of the single fiber having a diameter of more than 500 nm with respect to the total fibers is preferably 70% by mass or less, and 60% by mass or less. Is more preferable, and it is especially preferable that it is 50 mass% or less. If the ratio of the single fiber whose diameter exceeds 500 nm is 70% by mass or less, the reinforcing effect of the thermoplastic resin composition is excellent.

(Standard deviation of average fiber diameter (value))
The standard deviation (σ) of the average fiber diameter of the cellulose nanofibers is preferably 20 nm or less, more preferably 15 nm or less, and particularly preferably 10 nm or less.

The small standard deviation of the average fiber diameter indicates that the average fiber diameter of the cellulose nanofiber is more uniform. When the standard deviation of the average fiber diameter of the cellulose nanofibers is 20 nm or less, the fiber diameter of the cellulose nanofibers is uniform, so that the problem of aggregation during kneading with the thermoplastic resin is solved, and the mechanical strength is reduced. Demonstrates the effect of improving and maintaining ductility (elongation). Note that the standard deviation of the average fiber diameter can be arbitrarily adjusted by, for example, selection of pulp fibers, pretreatment, and refinement treatment.

(Average fiber length)
The average fiber length (length of single fiber) of the cellulose nanofiber is preferably 1 to 5,000 μm, more preferably 2 to 4,000 μm, and particularly preferably 3 to 3,000 μm. . When the average fiber length is 5,000 μm or less, the problem that the fibers are entangled and aggregated during kneading with the thermoplastic resin is solved. The average fiber length can be arbitrarily adjusted by, for example, selection of pulp fibers, pretreatment, and refinement treatment.

(aspect ratio)
In this embodiment, the aspect ratio is a value obtained by dividing the average fiber length by the average fiber width. The greater the aspect ratio, the greater the reinforcement effect because there are more places where the thermoplastic resin is caught. On the other hand, it is considered that the ductility of the thermoplastic resin is lowered by the amount of more caught. When an inorganic filler is kneaded with a thermoplastic resin, the tensile strength improves as the aspect ratio of the filler increases, but the tensile elongation at break decreases significantly (see Non-Patent Document 1).

  In order to improve the mechanical strength while maintaining the ductility of the resin to some extent, the aspect ratio is preferably 2 to 1,300,000, more preferably 4 to 700,000, and 7 to 300,000. 000 is particularly preferred.

(Water retention)
The water retention of the cellulose nanofiber is preferably 500% or less, more preferably 490% or less, and particularly preferably 480%. When the water retention exceeds 500%, the drainage, the drying property, and the compatibility with the thermoplastic resin tend to be inferior.

  Moreover, in order to make the reinforcing effect of the thermoplastic resin composition excellent, it is necessary to sufficiently dry the cellulose nanofibers and perform uniform dispersion in the thermoplastic resin. However, since cellulose nanofibers have high cohesiveness, they tend to aggregate during a drying process or a kneading process with a thermoplastic resin. Therefore, the water retention of the cellulose nanofiber is set to 500% or less, and the drainage, the drying property, and the compatibility with the thermoplastic resin are excellent, so that the drying treatment and the kneading treatment with the thermoplastic resin are performed. Aggregation can be suppressed and the reinforcing effect of the thermoplastic resin composition can be made sufficient. The water retention can be arbitrarily adjusted by, for example, selection of pulp fibers, pretreatment, and refinement treatment.

(Crystallinity)
The crystallinity of the cellulose nanofiber is preferably 50% or more, more preferably 55% or more, and particularly preferably 60% or more. If the degree of crystallinity is less than 50%, the compatibility with the thermoplastic resin is improved, but the strength of the fiber itself is lowered, so that the reinforcing effect of the thermoplastic resin composition tends to be inferior.

  On the other hand, the crystallinity of the cellulose nanofiber is preferably 90% or less, more preferably 88% or less, and particularly preferably 86% or less. If the degree of crystallinity exceeds 90%, the proportion of strong hydrogen bonds in the molecule increases and the fiber itself becomes stiff, but the compatibility with the thermoplastic resin is reduced and the reinforcing effect of the thermoplastic resin composition is poor. Tend. In addition, it tends to be difficult to chemically modify the cellulose nanofibers. Note that the crystallinity can be arbitrarily adjusted by, for example, selection of pulp fibers, pretreatment, and refinement.

(Peak value)
The peak value in the pseudo particle size distribution curve of the cellulose nanofiber is preferably one peak. In the case of one peak, the cellulose nanofiber has high fiber length and fiber diameter uniformity, and is excellent in drying properties. Moreover, when the fiber diameter and fiber length uniformity are high, the reinforcing effect of the thermoplastic resin composition is high, and the uniformity of the reinforcing effect is also excellent.

  The peak value of the nanofiber is preferably 5 μm or more, more preferably 7 μm or more, and particularly preferably 9 μm or more. In order to make the peak value less than 5 μm, it is necessary to carry out the micronization treatment of the cellulose nanofiber for a long time, which leads to an increase in production cost.

  On the other hand, the peak value of cellulose nanofibers is preferably 25 μm or less, more preferably 23 μm or less, and particularly preferably 21 μm or less. If the peak value exceeds 25 μm, miniaturization is insufficient and the fiber diameter and fiber length tend to be inferior.

(Half width)
The half-value width of the peak value in the pseudo particle size distribution curve of the aqueous dispersion of cellulose nanofibers is a value (μm) obtained by subtracting the particle size at a cumulative frequency of 25% from the particle size at a cumulative frequency of 75%. For example, if the number of pseudo particles mapped is 1,000, the particle size of the pseudo particle having the 250th size is subtracted from the particle size of the pseudo particle having the 750th size from the smaller one. The half-value width of the peak value here.

  When a fibrous sample is measured with a particle size distribution, the fibrous particle is regarded as a sphere and the particle size is calculated, so that the half-value width increases as the aspect ratio increases. It is considered that the half-value width of the particle size distribution is reduced by cutting the fibers by enzyme treatment or the like and aligning the fiber lengths.

  If the full width at half maximum is 15 μm or less, the cellulose nanofiber has a high uniformity in fiber length and fiber diameter, and has an aspect ratio that can obtain a reinforcing effect while retaining the ductility of the resin to some extent when blended with the resin. It is thought that it has been prepared.

(Pulp viscosity)
The pulp viscosity of the cellulose nanofiber is preferably 1.5 cps or more, more preferably 2.0 cps or more. When the pulp viscosity is less than 1.5 cps, the reinforcing effect of the thermoplastic resin composition tends to be inferior when the dispersion is kneaded with the thermoplastic resin due to the low degree of polymerization of the cellulose nanofibers. .

  Moreover, the pulp viscosity of the cellulose nanofiber is preferably 7.0 cps or less, and more preferably 6.5 cps or less. When the pulp viscosity exceeds 7.0 cps, the cellulose nanofiber dispersion cannot be sufficiently suppressed when the cellulose nanofiber dispersion is kneaded with the thermoplastic resin, and the reinforcing effect of the thermoplastic resin composition tends to be inferior. is there.

(Tentacle test)
The tentacle test is a test that is a factor in the progress of the micronization process. 1 mL of a cellulose nanofiber aqueous dispersion having a concentration of 2% by mass is placed on the index finger, the dispersion is sandwiched between the thumb and index finger, and the thumb is 20 times. Is a test for visually confirming whether or not the fibrous material remains between the thumb and forefinger.

  The micronization treatment is preferably performed so that no fibrous material remains in this tentacle test. If the fibrous material remains, the uniformity of the fiber diameter and fiber length of the cellulose nanofiber tends to be inferior.

  In addition, the inventors have conducted various tests and studies, and according to this tentacle test, it has been recognized that the progress of the miniaturization process can be quickly confirmed and the manufacturing efficiency can be improved. .

(Other fibers)
Cellulose nanofibers should contain one or more microfibrils called microfibril cellulose, microfibrillar microfibers, microfiber cellulose, microfibrillated cellulose, super microfibril cellulose, etc. In addition, these fine fibers may be included. Moreover, the fiber which refined | miniaturized these fine fibers further can also be included, and may be included.

  In addition to the above, kenaf, jute hemp, manila hemp, sisal hemp, husk, cocoon, cocoon, banana, pineapple, coconut, corn, sugar cane, bagasse, palm, papyrus, cocoon, esparto, sabaigrass, wheat, rice, bamboo, Fibers derived from plant materials obtained from various plant bodies such as various conifers (such as cedar and cypress), broad-leaved trees, and cotton can also be included.

(Dispersion)
Cellulose nanofibers obtained by micronization are dispersed in an aqueous medium to obtain a dispersion. The total amount of the aqueous medium is particularly preferably water, but an aqueous medium in which a part of the aqueous medium is another liquid having compatibility with water can also be preferably used. As other liquids, lower alcohols having 3 or less carbon atoms can be used.

(Solid content concentration)
The solid content concentration of the dispersion is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and particularly preferably 2.0% by mass or more. The solid content concentration of the dispersion is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

(B type viscosity)
When the concentration of the cellulose nanofiber is 1% by mass (w / w), the B-type viscosity of the dispersion is preferably 1,300 cps or less, more preferably 1,200 cps or less, and 1,100 cps. It is particularly preferred that When the B-type viscosity of the dispersion exceeds 1,300 cps, a large amount of energy is required to knead the cellulose nanofiber dispersion and the thermoplastic resin, that is, to disperse the cellulose nanofiber in the thermoplastic resin. This leads to an increase in manufacturing costs.

  On the other hand, the B-type viscosity of the dispersion is preferably 10 cps or more, more preferably 30 cps or more, and particularly preferably 50 cps or more. When the B-type viscosity of the dispersion is less than 10 cps, the reinforcing effect of the thermoplastic resin composition tends to be inferior when the dispersion is kneaded with the thermoplastic resin due to the low degree of polymerization of the cellulose nanofibers. It is in.

(Thermoplastic resin)
Examples of the thermoplastic resin include polyolefins such as polypropylene (PP) and polyethylene (PE), polyester resins such as aliphatic polyester resins and aromatic polyester resins, polyacrylic resins such as polystyrene, methacrylate, and acrylate, polyamide resins, One type or two or more types can be selected and used from polycarbonate resin, polyacetal resin and the like.

  However, it is preferable to use at least one of polyolefin and polyester resin. As the polyolefin, it is preferable to use polypropylene. Furthermore, examples of the polyester resin include aliphatic lactic acid resins such as polylactic acid and polycaprolactone. Examples of the aromatic polyester resin include polyethylene terephthalate and the like. It is preferable to use a polyester resin having the above (also simply referred to as “biodegradable resin”).

  As a biodegradable resin, it can select and use 1 type (s) or 2 or more types from hydroxycarboxylic acid type aliphatic polyester, caprolactone type aliphatic polyester, dibasic acid polyester etc., for example.

  Examples of the hydroxycarboxylic acid-based aliphatic polyester include homopolymers of hydroxycarboxylic acids such as lactic acid, malic acid, glucose acid, and 3-hydroxybutyric acid, and copolymers using at least one of these hydroxycarboxylic acids. One type or two or more types can be selected and used from polymers and the like. However, it is preferable to use polylactic acid, a copolymer of the above hydroxycarboxylic acid excluding lactic acid and lactic acid, polycaprolactone, a copolymer of at least one of the above hydroxycarboxylic acids and caprolactone, It is particularly preferred to use it.

  As this lactic acid, for example, L-lactic acid, D-lactic acid or the like can be used, and these lactic acids may be used alone or in combination of two or more.

  As the caprolactone-based aliphatic polyester, for example, one or two or more kinds of polycaprolactone homopolymers, copolymers of polycaprolactone and the like and the above-mentioned hydroxycarboxylic acid can be selected and used. .

  As the dibasic polyester, for example, one or two or more kinds selected from polybutylene succinate, polyethylene succinate, polybutylene adipate and the like can be used.

  A biodegradable resin may be used individually by 1 type, or may use 2 or more types together.

  The thermoplastic resin may contain an inorganic filler, preferably in a proportion that does not hinder thermal recycling. Examples of the inorganic filler include simple elements of metal elements in Group I to Group VIII of the periodic table such as Fe, Na, K, Cu, Mg, Ca, Zn, Ba, Al, Ti, and silicon elements. Examples thereof include oxides, hydroxides, carbon salts, sulfates, silicates, sulfites, and various clay minerals composed of these compounds.

  Specifically, for example, barium sulfate, calcium sulfate, magnesium sulfate, sodium sulfate, calcium sulfite, zinc oxide, silica, heavy calcium carbonate, light calcium carbonate, aluminum borate, alumina, iron oxide, calcium titanate, hydroxide Examples include aluminum, magnesium hydroxide, calcium hydroxide, sodium hydroxide, magnesium carbonate, calcium silicate, clay lastonite, glass beads, glass powder, silica sand, meteorite, quartz powder, diatomaceous earth, and white carbon. .

  A plurality of the above inorganic fillers may be contained. Moreover, it may be contained in waste paper pulp.

(Other raw materials)
In addition to the compatibilizer described later, the raw material of the thermoplastic resin composition includes, for example, one or more of antistatic agents, flame retardants, antibacterial agents, colorants, radical scavengers, foaming agents and the like. It can select and add in the range which does not inhibit the effect of this invention.

  These raw materials may be kneaded together at the time of kneading the dispersion of cellulose nanofibers and the thermoplastic resin, kneaded into both kneaded materials, or kneaded by other methods. However, in terms of production efficiency, it is preferable to knead together when the cellulose nanofiber dispersion and the thermoplastic resin are kneaded.

(Mixing ratio)
The blending ratio of the cellulose nanofiber and the thermoplastic resin is preferably 1 part by mass or more for the cellulose nanofiber and 99 parts by mass or less for the thermoplastic resin, 2 parts by mass or more for the cellulose nanofiber, and 98 parts by mass for the thermoplastic resin. More preferably, the amount of cellulose nanofibers is 3 parts by mass or more, and the thermoplastic resin is 97 parts by mass or less.

  The cellulose nanofiber is preferably 50 parts by mass or less, the thermoplastic resin is preferably 50 parts by mass or more, the cellulose nanofiber is 40 parts by mass or less, and the thermoplastic resin is more preferably 60 parts by mass or more. It is particularly preferable that the nanofiber is 30 parts by mass or less and the thermoplastic resin is 70 parts by mass or more. However, when the blending ratio of the cellulose nanofiber is 3 to 10 parts by mass, the strength of the thermoplastic resin composition, in particular, the bending strength and the tensile modulus can be remarkably improved.

  In addition, the content rate of the cellulose nanofiber and the thermoplastic resin contained in the finally obtained thermoplastic resin composition is usually the same as the above-described blending ratio of the cellulose nanofiber and the thermoplastic resin.

(Dehydration and drying process)
Cellulose nanofibers and thermoplastic resins are dehydrated and dried. However, it is preferable to perform a dehydration process and a drying process together. By processing both together, a large amount and efficient processing becomes possible. The dehydration process and the drying process can be performed in separate processes / apparatuses, but can also be performed in the same process / apparatus, and it is more efficient to perform the same process / apparatus.

  For dehydration / drying treatment, for example, one or more selected from freeze dryer, vacuum dryer, heat dryer, stationary dryer, spray dryer, kneader, twin screw kneader, etc. are used. can do.

  However, for the dehydration / drying treatment, it is preferable to use one or more selected from freeze dryer, heat dryer, kneader, and twin screw kneader. More preferably it is used. When a freeze dryer, a heat dryer, a kneader or a biaxial kneader is used, the cellulose nanofibers can be dried without agglomeration. In particular, when a cellulose nanofiber is dehydrated and dried while being heated and stirred together with a thermoplastic resin using a kneader or a biaxial kneader, a large amount and an efficient treatment can be performed.

  When using a freeze dryer, water or t-butanol can be used from the viewpoint of preventing aggregation of cellulose nanofibers. The use of water has the advantage that no solvent processing problems arise. In addition, when t-butanol is used, there are advantages that treatment in a short time is possible, energy efficiency is excellent, and aggregation of cellulose nanofibers can be more reliably prevented.

  Examples of the heat dryer include a Banbury mixer, a single screw or a multi-screw kneader having two or more screws, a kneader, a solid-phase shear extruder, a lab plast mill, a planetary stirrer, etc. It is preferable to use one or more selected from (heating stirrer).

  The dehydration / drying process is performed by melting a thermoplastic resin in the “masterbatch method” to be described later, and is performed without melting the thermoplastic resin in the “solid phase shearing method”. When kneading nanofibers simply, they may be melted or not melted.

  However, in the masterbatch method and the solid-phase shearing method, the cellulose nanofiber dispersion is dehydrated and dried together with the thermoplastic resin before the dehydration and drying treatment with a continuous filtration apparatus equipped with a centrifuge or filter cloth or the like. It is preferable to concentrate to a solid content concentration of%. By pre-concentrating, the time for drying or dehydration and drying can be shortened.

(Kneading process)
The cellulose nanofibers and thermoplastic resin that have undergone the dehydration and drying treatment are kneaded.

  For this kneading treatment, for example, one or more types selected from a single-screw or bi-axial or more multi-screw kneader, a mixing roll, a kneader, a roll mill, a Banbury mixer, a screw press, a disperser, etc. are used. can do.

  The temperature of the kneading treatment is not less than the glass transition point of the thermoplastic resin and not more than the melting point, and varies depending on the type of the thermoplastic resin, but is preferably 80 to 220 ° C, more preferably 90 to 210 ° C, A temperature of 100 to 200 ° C. is particularly preferable.

  The kneading time is preferably 1 to 180 minutes, more preferably 2 to 100 minutes, and particularly preferably 3 to 20 minutes.

(Compatibilizer)
It is preferable to add a compatibilizer to the kneaded cellulose nanofiber and the thermoplastic resin. When a compatibilizing agent is added, the compatibility between the cellulose nanofibers and the thermoplastic resin can be assisted, and the strength, particularly the bending strength, of the resulting thermoplastic resin composition can be improved.

  As the compatibilizing agent, it is preferable to use one having a structure in which the polymer main chain has an acid anhydride group in the side chain.

  As the acid anhydride, for example, one or more kinds can be selected and used from maleic anhydride, itaconic anhydride, citraconic anhydride, citric anhydride, etc., and maleic anhydride is used. Is preferred.

  The blending mass ratio of the thermoplastic resin, the compatibilizing agent and the cellulose nanofiber in the solid content is preferably 40 to 99: 0 to 10: 1 to 50 when no compatibilizing agent is added. Is preferably 40-98.9: 0.1-10: 1-50, more preferably 52-97.5: 0.5-8: 2-40, 65 It is especially preferable that it is -96: 1-5: 3-30.

(Master batch method)
Next, referring to FIG. 1, a method of producing a thermoplastic resin composition by using a thermoplastic resin and cellulose nanofibers as raw materials and adding a compatibilizing agent, the strength of the resulting thermoplastic resin composition. Will be described below (hereinafter also referred to as “master batch method”).

  In this master batch method, first, pulp fibers (P) are pretreated (10) such as beating treatment and enzyme treatment, and then refined (20) to obtain cellulose nanofibers. Mix with water (W) to make a dispersion (CNF).

  In addition, water (W) can be added in advance prior to the pretreatment (10) such as the beating treatment and the enzyme treatment.

  Next, the dispersion (CNF) and a thermoplastic resin, preferably a low melting point thermoplastic resin (Rx), are dehydrated and dried (30x), and subjected to a primary kneading process (40x). Then, a thermoplastic resin (Ry) and further a compatibilizer (Rz) are added to the primary kneaded product, and a secondary kneading process (50x) and a molding process (60) are performed to obtain a thermoplastic resin composition (S). .

  Here, regarding the kneading of the dispersion liquid (CNF) and the low-melting-point thermoplastic resin (Rx), first, the low-melting-point thermoplastic resin (Rx) is melted, and the dispersion liquid is dissolved in the molten low-melting-point thermoplastic resin (Rx). It is preferable to gradually add (CNF).

  The reason why the thermoplastic resin (Ry) is added (blended) to the primary kneaded material separately from the low melting point thermoplastic resin (Rx) is as follows. That is, the low melting point thermoplastic resin (Rx) plays a role as a substrate for dispersing the nanofibers. Moreover, the primary kneaded material in which the low-melting point thermoplastic resin (Rx) and the nanofiber are combined plays a role as a so-called master batch for the purpose of coloring or reinforcement. And the target thermoplastic resin composition can be obtained by knead | mixing this masterbatch and thermoplastic resin (Ry) so that it may become a desired compounding ratio.

  The blending ratio of the thermoplastic resin (Ry) is preferably 100 to 10,000 parts by mass, and 200 to 10,000 parts by mass with respect to 100 parts by mass of the low melting point thermoplastic resin (Rx) on a mass basis. Is more preferable, and 300 to 10,000 parts by mass is particularly preferable.

  The master batch method has one feature in that a thermoplastic resin such as a low-melting-point thermoplastic resin (Rx) is melted in the dehydration / drying process (30x) and the primary kneading process (40x).

  In the master batch method, the temperature of the dehydration / drying treatment (30x) is appropriately set according to the type of the thermoplastic resin. For example, when using a low melting point polypropylene (melting point 90 ° C.) which is a low melting point thermoplastic resin (Rx) as the thermoplastic resin, it is preferably 90 to 130 ° C., more preferably 90 to 120 ° C. 90 to 110 ° C. is particularly preferable.

  In addition, when using normal polypropylene (melting | fusing point 160 degreeC), it is preferable to set it as 160-220 degreeC, It is more preferable to set it as 160-210 degreeC, It is especially preferable to set it as 160-200 degreeC.

  The time for the dehydration / drying treatment (30x) is preferably 80 to 1200 minutes, more preferably 90 to 1100 minutes, and particularly preferably 100 to 1000 minutes.

  Furthermore, as a device for dehydration / drying treatment (30x), for example, a kneader, a single screw or a multi-screw kneader with two or more screws, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, a disperser, etc. 1 type or 2 types or more can be selected and used from the apparatus which can shorten drying time like a decompression type kneader.

  The temperature of the primary kneading treatment (40x) is also set as appropriate according to the type of thermoplastic resin. For example, when using a low melting point polypropylene (melting point 90 ° C.) which is a low melting point thermoplastic resin (Rx) as the thermoplastic resin, it is preferably 90 to 130 ° C., more preferably 90 to 120 ° C. 90 to 110 ° C. is particularly preferable.

  The time of the primary kneading treatment (40x) is preferably 1 to 100 minutes, more preferably 2 to 80 minutes, and particularly preferably 3 to 60 minutes.

  Examples of the primary kneading apparatus (40x) include, for example, a kneader, a single-screw or multi-screw kneader, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, a disperser, etc. 1 type or 2 types or more can be selected and used from the apparatus which can shorten drying time like a machine.

  The temperature of the secondary kneading treatment (50x) after adding the compatibilizing agent (Rz) is appropriately set according to the type of the thermoplastic resin (Ry) added after the primary kneading treatment (40x). For example, when using a thermoplastic resin that does not have a low melting point as the thermoplastic resin (Ry), such as polypropylene (melting point 160 ° C.), it is preferably 160 to 220 ° C., more preferably 160 to 210 ° C. Preferably, it is 160-200 degreeC.

  The time for the secondary kneading treatment (50x) is preferably 1 to 180 minutes, more preferably 2 to 80 minutes, and particularly preferably 3 to 20 minutes.

  Examples of the secondary kneading apparatus (50x) include, for example, a kneader, a single screw or a multi-screw kneader with two or more screws, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, a disperser, etc. 1 type or 2 types or more can be selected and used from the apparatus which can shorten drying time like a kneading machine.

  The temperature of the forming treatment (60) is preferably 160 to 220 ° C, more preferably 160 to 210 ° C, and particularly preferably 160 to 200 ° C.

  The time for the forming treatment (60) is preferably 1 to 200 minutes, more preferably 1 to 190 minutes, and particularly preferably 1 to 180 minutes.

  Examples of the molding processing apparatus include one or more of injection molding machines, blow molding machines, hollow molding machines, blow molding machines, compression molding machines, extrusion molding machines, vacuum molding machines, and pressure molding machines. Can be selected and used.

(Solid phase shearing method)
Next, with reference to FIG. 1, a method for significantly improving the strength of the obtained thermoplastic resin composition (also simply referred to as “solid-phase shearing method”), which is different from the above master batch method, will be described.

  In this solid-phase shearing method, first, pulp fibers (P) are pretreated (10), then refined (20) to obtain cellulose nanofibers, and these cellulose nanofibers are mixed with water (W). To make a dispersion (CNF). In addition, prior to the pretreatment (10), water (W) can be added in advance.

  Next, the dispersion (C) and the thermoplastic resin (Ry) are dehydrated and dried (30y), and subjected to solid phase shearing (40y). Then, a compatibilizing agent (Rz) is added to the solid phase sheared material, and kneading treatment (50y) and molding treatment (60) are performed to obtain the thermoplastic resin composition (S).

  This solid-phase shearing method has one feature in that the thermoplastic resin is not melted during the dehydration / drying treatment (30y). In this solid-phase shearing method, cellulose nanofibers are embedded and dispersed in the thermoplastic resin while moisture is evaporated in the process of dehydration / drying treatment (30y) and solid-phase shearing treatment (40y). The Thereby, cellulose nanofibers are interspersed in the thermoplastic resin (Ry), and the dry mixed powder of cellulose nanofiber and thermoplastic resin is also characterized.

  The temperature during the dehydration / drying treatment (30y) is appropriately set according to the type of the thermoplastic resin (Ry). For example, when polypropylene (melting point 160 ° C.) is used as the thermoplastic resin (Ry), it is preferably 50 to 160 ° C., more preferably 55 to 155 ° C., and 60 to 150 ° C. Particularly preferred.

  The duration of the dehydration / drying treatment (30y) is preferably 1 to 300 minutes, more preferably 2 to 270 minutes, and particularly preferably 3 to 240 minutes.

  Examples of the dehydration / drying treatment (30y) device include a simple stirring device, a kneader, a single screw or a multi-screw kneader with two or more screws, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, and a disperser. Etc. (including a device such as a vacuum kneader that can shorten the drying time) can be used by selecting one or more.

  The larger the area in which the cellulose nanofibers and the thermoplastic resin (Ry) are in contact with each other, the better the efficiency of the solid phase shearing treatment (40y). Therefore, the shape of the thermoplastic resin (Ry) has an average particle diameter of 1 to 1,000 μm. It is preferable to keep the powder form.

  The temperature of the solid phase shear treatment (40y) is also set as appropriate according to the type of the thermoplastic resin (Ry). For example, when polypropylene (melting point 160 ° C.) is used as the thermoplastic resin (Ry), it is preferably 50 to 160 ° C. as in the case of dehydration / drying treatment (30 y), and 55 to 155 ° C. Is more preferable, and 60 to 150 ° C. is particularly preferable.

  The time for the solid phase shear treatment (40y) is preferably 1 to 180 minutes, more preferably 2 to 170 minutes, and particularly preferably 3 to 160 minutes.

  Examples of the solid phase shearing (40y) apparatus include a kneader, a single-screw or multi-screw kneader, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, a disperser, etc. 1 type or 2 types or more can be selected and used from the apparatus which can shorten drying time like a kneading machine.

  The kneading treatment (50y) after adding the compatibilizing agent (Rz) is preferably 160 to 220 ° C. when polypropylene (melting point 160 ° C.) is used as the thermoplastic resin (Ry). More preferably, the temperature is set to 160 to 200 ° C.

  The time for the kneading treatment (50y) is preferably 1 to 180 minutes, more preferably 2 to 80 minutes, and particularly preferably 3 to 20 minutes.

  Examples of the kneading apparatus (50y) include, for example, a kneader, a uniaxial or biaxial or more multi-axial kneader, a mixing roll, a kneader, a roll mill, a Banbury mixer, a Henschel mixer, a screw press, a disperser, etc. 1 type or 2 types or more can be selected and used.

(Molding process)
The cellulose nanofiber and the thermoplastic resin (kneaded material) to which the compatibilizing agent is added are kneaded again if necessary and then formed into a desired shape. In addition, although the cellulose nanofiber is disperse | distributed to the kneaded material, it is excellent in moldability.

  The size, thickness, shape, and the like of the molding are not particularly limited, and can be, for example, a sheet shape, a pellet shape, a powder shape, a fiber shape, and the like.

  In the case of using polypropylene (melting point: 160 ° C.) as the thermoplastic resin (Ry), the temperature during the molding process (60) is preferably 160 to 220 ° C., more preferably 160 to 210 ° C. 160 to 200 ° C. is particularly preferable.

  The time for the forming treatment (60) is preferably 1 to 200 minutes, more preferably 1 to 190 minutes, and particularly preferably 1 to 180 minutes.

  As an apparatus for the molding process (60), for example, one of injection molding machine, blow molding machine, hollow molding machine, blow molding machine, compression molding machine, extrusion molding machine, vacuum molding machine, pressure molding machine, etc. Two or more types can be selected and used.

  The molding process can be performed by a known molding method, for example, mold molding, injection molding, extrusion molding, hollow molding, foam molding, or the like. Further, the kneaded product can be spun into a fiber and mixed with the above-described plant material or the like to form a mat or board. The fiber mixing can be performed by, for example, a method in which air fibers are simultaneously deposited.

  This molding process can be performed following the kneading process, or the kneaded product is once cooled and chipped using a crusher or the like, and then the chip is put into a molding machine such as an extrusion molding machine or an injection molding machine. It can also be done.

(Definition of terms, measurement methods, etc.)
The terms in the specification are as follows unless otherwise specified.

(Average fiber diameter)
100 ml of an aqueous dispersion of cellulose nanofibers having a solid content concentration of 0.01 to 0.1% by mass is filtered through a Teflon (registered trademark) membrane filter, and the solvent is substituted once with 100 ml of ethanol and three times with 20 ml of t-butanol. . Next, the sample is freeze-dried and coated with osmium. This sample is observed with an electron microscope SEM image at a magnification of 5000 times, 10000 times, or 30000 times depending on the width of the constituent fibers. Specifically, two diagonal lines are drawn on the observation image, and three straight lines passing through the intersections of the diagonal lines are arbitrarily drawn. Further, the total width of 100 fibers intersecting with the three straight lines is visually measured. And let the median diameter of a measured value be an average fiber diameter.

(Standard deviation of average fiber diameter)
This is a value obtained by measuring the width of 100 fibers by the above average fiber diameter calculation method and obtaining the standard deviation (σ) from the measured value of the 100 fiber widths.

(Average fiber length)
Similarly to the case of the average fiber diameter, the length of each fiber is visually measured. The median length of the measured value is the average fiber length.

(aspect ratio)
It is a value obtained by dividing the average fiber length by the average fiber width (diameter).

(Water retention)
JAPAN TAPPI No. Measured according to 26: 2000.

(Crystallinity)
It is a value measured by an X-ray diffraction method in accordance with “General Rules for X-ray Diffraction Analysis” of JIS-K0131 (1996).
In addition, a cellulose nanofiber has an amorphous part and a crystalline part, and a crystallinity degree means the ratio of the crystalline part in the whole cellulose nanofiber.

(Peak value)
Measured according to ISO-13320 (2009). More specifically, the volume-based particle size distribution in an aqueous dispersion of cellulose nanofibers is examined using a particle size distribution measuring device (laser diffraction / scattering particle size distribution measuring instrument manufactured by Seishin Corporation). And the median diameter of a cellulose nanofiber is measured from this distribution. This median diameter is the peak value.

(Half width)
It is a value (μm) obtained by subtracting the particle size at a cumulative frequency of 25% from the particle size at a cumulative frequency of 75% in the particle size distribution.

(Pulp viscosity)
Measured according to JIS-P8215 (1998). In addition, it means that the polymerization degree of a cellulose is so high that a pulp viscosity is high.

(B type viscosity)
An aqueous dispersion of cellulose nanofibers having a solid content concentration of 1% is measured in accordance with “Method for measuring viscosity of liquid” in JIS-Z8803 (2011). The B type viscosity is a resistance torque when the slurry is stirred, and the higher the viscosity, the more energy required for stirring.

(Freeness)
It is a value measured in accordance with JIS P8121-2: 2012.

Next, examples of the present invention will be shown to clarify the effects of the present invention.
Example 1
A hardwood bleached kraft pulp for papermaking (LBKP) with a moisture content of 70% or more loosened with a kneader or the like, a polysaccharide hydrolase (CX7L, Genencor Corp.) in an amount of 1% by weight with respect to dry pulp, and a pulp concentration of 10 Water in an amount of mass% was added and reacted at 50 ° C. for 5 hours. After the reaction, the enzyme was inactivated at 105 ° C. for 5 minutes, and the pulp was filtered and washed several times with water, and then water was added to obtain a 2 mass% aqueous dispersion. This aqueous dispersion was beaten using a Niagara beater until the freeness was 100 ml or less, and further refined using a jet mill (manufactured by Joko Corporation) (5 passes).

  As described above, a 2-3% by mass cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15% by mass cellulose nanofiber slurry (dispersion). This dispersion is a 500 ml beaker so that the polypropylene powder (Novatech PP injection molding grade MA3 manufactured by Nippon Polypro, particle size of about 500 μm) and the 7-15 mass% cellulose nanofiber slurry are 90: 5 in terms of dry mass ratio. The mixture was stirred for 2 hours using a propeller-type heat stirrer (70 ° C., 300 rpm) and dried until the water content became 5 to 10% (drying treatment).

  Further, using a kneader (Laboplast Mill, Toyo Seiki, 70 ° C., 60 rpm), solid-phase shear treatment was performed for 1 hour to obtain a dry mixed powder of cellulose nanofibers and polypropylene.

  This dry mixed powder was put into a 500 ml beaker and mixed so that the dry mixed powder and maleic acid-modified polypropylene powder (KAYABURI made by Kayaku Akzo, compatibilizer) became a dry mass ratio of 95: 5. The mixed powder thus obtained was kneaded using a biaxial kneader (45 rpm, 180 ° C.) to obtain polypropylene (thermoplastic composition) containing 5% by mass of cellulose nanofibers. This thermoplastic composition was made into a cylindrical pellet having a diameter of 2 mm and a length of 2 mm using a pelleter. This pellet was a 180 ° C. dumbbell-shaped test piece (grip distance 20 mm, width 3.9 mm, thickness 1.97 mm) and a rectangular parallelepiped test piece (length 59 mm, width 9.6 mm, thickness 3.8 mm). And injection molded.

(Comparative Example 1)
A 23% 2% aqueous dispersion of hardwood bleached kraft pulp for papermaking (LBKP) loosened with a kneader or the like was beaten using a Niagara beater until the freeness was 100 ml or less, and a jet mill (manufactured by Joko) Was refined (10 passes). Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15% by mass cellulose nanofiber slurry (dispersion). In the same manner as in Example 1, this dispersion was dried, solid-phase sheared, kneaded, and injection molded.

(Comparative Example 2)
A hardwood bleached kraft pulp for papermaking (LBKP) with a moisture content of 70% or more loosened with a kneader or the like, a polysaccharide hydrolase (CX7L, Genencor Corp.) in an amount of 1% by weight with respect to dry pulp, and a pulp concentration of 10 Water in an amount of mass% was added and reacted at 50 ° C. for 5 hours. After the reaction, the enzyme was inactivated at 105 ° C. for 5 minutes, and the pulp was filtered and washed several times with water, and then water was added to obtain a 2 mass% aqueous dispersion. This aqueous dispersion was beaten using a Niagara beater until the freeness was 100 ml or less, and further refined using a grinder (mass colloider from Masuko Sangyo Co., Ltd.). Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15 mass% cellulose nanofiber slurry (dispersion) having a particle size distribution volume average diameter of 20 μm or less. In the same manner as in Example 1, this dispersion was dried, solid-phase sheared, kneaded, and injection molded.

(Comparative Example 3)
A 2% by weight aqueous dispersion 23L of hardwood bleached kraft pulp for papermaking (LBKP) loosened with a kneader or the like was beaten using a Niagara beater until the freeness was 100 ml or less, and then a grinder (masco of Masuko Sangyo Co., Ltd.). (Leider). Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15 mass% cellulose nanofiber slurry (dispersion) having a particle size distribution volume average diameter of 20 μm or less. In the same manner as in Example 1, this dispersion was dried, solid-phase sheared, kneaded, and injection molded.

(Comparative Example 4)
A 2% by weight aqueous dispersion 23L of paper bleached machine pulp (BTMP) loosened with a kneader or the like was beaten using a Niagara beater until the freeness was 100 ml or less, and then a grinder (mass colloider from Masuko Sangyo Co., Ltd.). ) Was used for the refinement treatment. Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15 mass% cellulose nanofiber slurry (dispersion) having a particle size distribution volume average diameter of 20 μm or less. In the same manner as in Example 1, this dispersion was dried, solid-phase sheared, kneaded, and injection molded.

(Comparative Example 5)
A 23% 2% aqueous dispersion of hardwood bleached kraft pulp for papermaking (LBKP) loosened with a kneader or the like was beaten using a Niagara beater until the freeness was 100 ml or less, and a jet mill (manufactured by Joko) Was refined (10 passes). Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15% by mass cellulose nanofiber slurry (dispersion). Next, low-melting polypropylene (El Modu S901, manufactured by Idemitsu Kosan Co., Ltd., melting point: about 80 ° C.) was charged into a kneader (laboratory plast mill manufactured by Toyo Seiki) adjusted to 105 ° C. and melted. Subsequently, the 7-15 mass% cellulose nanofiber dispersion was gradually added so that the dry mass ratio of the low melting point polypropylene and the cellulose nanofiber was 50:50, thereby evaporating water. After the introduction of the dispersion liquid was completed, it was dried and dispersed at 80 rpm for 20 minutes to obtain a 50% cellulose nanofiber blended master batch. This master batch was cut into a 2 mm diameter and 2 mm long cylindrical shape using a pelleter to obtain pellets that could be easily put into a biaxial kneader. Next, polypropylene pellets (Novatech PP injection molding grade MA3 manufactured by Nippon Polypro Co., Ltd., melting point 158 ° C.), the master batch pellets, maleic acid-modified polypropylene pellets (Yumex 1010 manufactured by Sanyo Chemical Industries) as a compatibilizer. The mixture was introduced into a 500 ml beaker and mixed so that the dry mass ratio was 80: 20: 1. This pellet mixture was kneaded at 45 rpm with a biaxial kneader prepared at 180 ° C. to obtain 10% by mass of cellulose nanofiber-containing polypropylene. This polypropylene was cut into a cylindrical shape having a diameter of 2 mm and a length of 2 mm with a pelleter to obtain 10% by mass blended polypropylene pellets of cellulose nanofibers. This pellet was injection molded in the same manner as in Example 1.

(Comparative Example 6)
A 2% by weight aqueous dispersion 23L of hardwood bleached kraft pulp for papermaking (LBKP) loosened with a kneader or the like was beaten using a Niagara beater until the freeness was 100 ml or less, and then a grinder (masco of Masuko Sangyo Co., Ltd.). (Leider). Thereby, a 2-3 mass% cellulose nanofiber slurry (dispersion liquid) having a peak value in the pseudo particle size distribution curve of 5 to 25 μm and a water retention of 500% or less was obtained. Therefore, this dispersion was further treated with a centrifuge (9,000 rpm) for 10 minutes to obtain a 7-15 mass% cellulose nanofiber slurry (dispersion) having a particle size distribution volume average diameter of 20 μm or less. This dispersion was obtained in the same manner as in Comparative Example 5 to obtain polypropylene pellets containing 10% by mass of cellulose nanofibers. This pellet was injection molded in the same manner as in Example 1.

(Comparative Example 7)
First, a 7-15 mass% cellulose nanofiber slurry (dispersion) was obtained in the same manner as in Comparative Example 4. This dispersion was obtained in the same manner as in Comparative Example 5 to obtain polypropylene pellets containing 10% by mass of cellulose nanofibers. This pellet was injection molded in the same manner as in Example 1.

(Comparative Example 8)
Polypropylene pellets (Novatech PP injection molding grade MA3 manufactured by Nippon Polypro, melting point 158 ° C.) were injection molded in the same manner as described in Example 1.

(Comparative Example 9)
In a 500 ml beaker, polypropylene powder (Novatec PP injection molding grade MA3 made by Nippon Polypro, particle size of about 500 μm), maleic acid-modified polypropylene powder (Kayaburd made by Kayaku Akzo, compatibilizer) is 90: 5 in dry mass ratio. Charged and mixed. This mixed powder is kneaded using a twin-screw kneader (45 rpm, 180 ° C.), and then this polypropylene is cut into a 2 mm diameter, 2 mm long cylindrical shape with a pelleter to obtain a compatibilizer-blended polypropylene pellet. It was. This pellet was injection molded in the same manner as in Example 1.

(Evaluation method)
Table 1 shows the results of a bending test and a tensile test for each test piece. The evaluation method was as follows.

(Bending test: elastic modulus and strength)
The rectangular parallelepiped test piece was measured in accordance with JIS K7171: 2008 (Plastic-Determination of bending characteristics). In addition, it means that an elasticity modulus and intensity | strength are so strong that a numerical value is large (high).

(Tensile test: elastic modulus, strength, elongation)
The dumbbell-shaped test piece was measured according to JIS K7161: 2014 (plastic-tensile property test method). In addition, it means that an elasticity modulus, intensity | strength, and elongation are so strong (high) that a numerical value is large.

  As described above, the thermoplastic resin composition of the present invention has a stronger strength (enhancement effect) than conventional thermoplastic resins. Therefore, it can be used not only for applications in which a thermoplastic resin has been used conventionally, but also for applications that have conventionally been countered for use due to insufficient strength. Preferably, a material having high mechanical strength while maintaining ductility, such as an automobile interior material or a toy, is used as a thermoplastic resin having essential physical properties. This is because, when a material that breaks immediately upon receiving a force from the outside is used as the material, the sharp fracture surface may come into contact with the human body and cause injury.

Specifically, for example, interior materials, exterior materials, structural materials, etc. of transportation equipment such as automobiles, trains, ships, airplanes, etc.
Cases such as PCs, TVs, telephones, watches and other electrical appliances, structural materials, internal parts, etc.
Mobile communication devices such as mobile phones, housings, structural materials, internal parts, etc.
Portable music playback equipment, video playback equipment, printing equipment, copying equipment, sports equipment, office equipment, toys, sports equipment, etc., structural materials, internal parts, etc.
Interior materials such as buildings and furniture, exterior materials, structural materials, etc.
Office equipment such as stationery,
In addition, packaging bodies, containers such as trays, protective members, partition members, etc.
Can be used as
Among the above, examples of automobile applications include interior materials, instrument panels, exterior materials, and the like. Specifically, for example, door base material, package tray, pillar garnish, switch base, quarter panel, armrest core material, door trim, seat structure material, console box, dashboard, various instrument panels, deck trim, bumper, Examples include spoilers and cowlings.
Moreover, as a building and a furniture use, the cover material of various furniture, such as a door cover material, a door structure material, a desk, a chair, a shelf, and a bag, etc. can be illustrated.

  10 ... Pretreatment, 20 ... Finening (defibration) treatment, 30x, 30y ... Drying treatment, 40x ... (Primary) kneading treatment, 40y ... Solid phase shearing treatment, 50 ... Compatibilizer addition treatment, 60 ... (Secondary) ) Kneading treatment, 70 ... Molding treatment, C ... Dispersion, P ... Pulp fiber, Rx ... Low melting point polypropylene, Ry ... Polypropylene other than low melting point polypropylene, Rz ... Compatibilizer, W ... Water.

Claims (7)

Cellulose nanofibers having a standard deviation (σ) of average fiber diameter of 20 nm or less, and a compatibilizer,
The peak value in the pseudo particle size distribution curve of the aqueous dispersion of cellulose nanofiber is 5 to 25 μm, and the half width of the peak is 15 μm or less,
When compared with a blank product that does not contain the cellulose nanofiber and the compatibilizer, the bending strength in accordance with JIS K7171: 2008 is 1.10 times or more,
In the tensile strength test based on JIS K7161: 2014, the retention of tensile elongation at break is 70% or more.
The thermoplastic resin composition characterized by the above-mentioned.
Here, the retention ratio of the tensile elongation at break is a value calculated by (tensile elongation at break of thermoplastic resin composition containing cellulose nanofiber and compatibilizing agent / tensile elongation at break of blank) × 100 (%). It is. The cellulose nanofiber has an average fiber diameter of 4 to 500 nm.
The thermoplastic resin composition according to claim 1. The cellulose nanofiber has a crystallinity of 50 to 90%.
The thermoplastic resin composition according to claim 1 or 2. The cellulose nanofiber has a water retention of 500% or less.
The thermoplastic resin composition according to claim 1. The cellulose nanofiber has one peak value and 5 μm or more.
The thermoplastic resin composition according to claim 1. The cellulose nanofiber has a pulp viscosity of 1.5 cps or more,
The thermoplastic resin composition according to claim 1.   The thermoplastic resin composition according to claim 1, wherein the compatibilizing agent is a modified product containing at least one selected from maleic anhydride, itotanic anhydride, citraconic anhydride, and anhydrous citric acid. .

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