JP2020132701A - Particle, and resin composition - Google Patents

Abstract

To improve physical properties of a plastic molded article containing a biomass material.SOLUTION: There is provided a particle composed of a particle core part made of a thermoplastic resin and a coating layer containing cellulose powder covering at least part of the particle core part. The particle may contain a first skid and a second skid having a melting point higher than the first skid. There is provided a resin composition that contains the thermoplastic resin and the cellulose powder of which the content is 20 mass%-50 mass% relative to the mass of the resin composition and further contains the first skid and the second skid having a melting point higher than the first skid.SELECTED DRAWING: Figure 1

Description

The present invention relates to particles and a resin composition, and more particularly to particles having a cellulose powder-containing coating layer and a resin composition produced by using the particles.

Plastic molded products containing biomass materials are attracting attention. Since the plastic molded product contains a biomass material as a substitute for a petroleum-based material, it is possible to reduce CO ₂ emitted during combustion. Examples of biomass materials include waste-based biomass (food waste, livestock excrement, construction waste, waste paper, etc.), unused biomass (non-edible parts of agricultural products, forest residue, etc.), and resource grains. it can. Examples of more specific biomass materials include wood flour, rice straw, bamboo, and old rice.

Regarding plastic molded products containing a biomass material, for example, Patent Document 1 below states that 50 to 70% by weight of starch, 20 to 40% by weight of thermoplastic resin, and 0.1 to 10% by weight of melting point of 60 to 10% by weight. It contains a low melting point additive of 100 ° C. and a high melting point additive having a melting point of 1 to 15% by weight of 100 ° C. to 150 ° C., and has a granular core portion of a thermoplastic resin, and the surface of the core portion of the granular material. A starch / resin composite molding obtained by melt-extruding a resin using a starch / resin composite intermediate granule as a raw material, which comprises a coating layer of a powder or granular material containing at least a starch containing a low melting point additive, which is attached to at least by a high melting point additive. The processed material is disclosed.

JP-A-2018-104629

There is a need to improve the physical properties of plastic molded products containing biomass materials. For example, if physical properties such as rigidity, heat resistance, and dimensional stability can be improved, it is considered that the applications of plastic molded products containing biomass materials can be further expanded and further contribute to the environment. Therefore, an object of the present invention is to improve the physical properties of a plastic molded product containing a biomass material.

The present inventors have found that a resin composition having a high content ratio of a biomass material and excellent physical properties can be produced by particles having a specific constitution.

That is, the present invention provides particles composed of a particle core portion made of a thermoplastic resin and a cellulose powder-containing coating layer covering at least a part of the particle core portion.
According to one embodiment of the present invention, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is the number of all cellulose fibers constituting the cellulose powder. It can account for 65% to 100%.
Among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm can account for 0% to 30% of the total number of cellulose fibers constituting the cellulose powder.
The particles can be used to form a film or sheet.
According to another embodiment of the present invention, the cellulose powder may have a particle size of 90% or more in 100 mesh passes.
The particles can be used for injection molding.
The coating layer may include a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant.
The second lubricant may comprise at least one compound selected from the group consisting of fatty acid metal salts, hydrocarbons, higher alcohols, fatty amides, and fatty acid esters.
The first lubricant may contain a glycerin fatty acid ester.
The particles may have a substantially spherical morphology with a diameter of 3 mm to 10 mm.

Further, the present invention contains a thermoplastic resin and a cellulose powder, and the content ratio of the cellulose powder is 20% by mass to 50% by mass with respect to the mass of the resin composition.
Also provided is a resin composition further comprising a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant.
According to one embodiment of the present invention, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is the number of all cellulose fibers constituting the cellulose powder. It can account for 65% to 100%.
According to another embodiment of the present invention, the cellulose powder may have a particle size of 90% or more for a 100 mesh pass.

The particles of the present invention can be used to produce a resin composition having a high cellulose content. Further, the resin composition is excellent in physical properties such as rigidity, heat resistance, and dimensional stability.
Further, by adopting a specific cellulose powder as the cellulose powder contained in the coating layer of the particles, the physical properties can be further improved.
The effect of the present invention is not necessarily limited to the effects described here, and may be any of the effects described in the present specification.

It is a schematic diagram of an example of a particle according to the present invention. It is a figure which shows the evaluation result of the flexural modulus. It is a figure which shows the evaluation result of the deflection temperature under load. It is a figure which shows the evaluation result of dimensional stability.

Hereinafter, embodiments for carrying out the present invention will be described in detail. It should be noted that the embodiments described below show an example of typical embodiments of the present invention, and the present invention is not limited to these embodiments.

1. 1. particle

A schematic diagram of the particles of the present invention is shown in FIG. As shown in FIG. 1, the particle 1 of the present invention is composed of a particle core portion 2 made of a thermoplastic resin and a cellulose powder-containing coating layer 3 covering at least a part of the particle core portion. The particles of the present invention are suitable for producing a cellulose-containing resin composition, and particularly suitable for producing a resin composition having a high cellulose content ratio. Furthermore, by using the particles of the present invention, the dispersibility of the cellulose powder in the resin composition can be improved. The particle core portion and the coating layer will be described below.

1-1. Particle core

The particle core portion is formed of a thermoplastic resin. The thermoplastic resin may be, for example, a polyolefin-based resin, a polystyrene-based resin, a polyamide-based resin, or a polyester-based resin, and is preferably a polyolefin-based resin.

The polyolefin-based resin is a polymer obtained by polymerization using olefins (for example, α-olefins) as a main monomer. The polyolefin-based resin may be, for example, a polyethylene-based resin, a polypropylene-based resin, or a mixture thereof. The polyethylene-based resin is a resin containing polyethylene as a main component, and can contain, for example, polyethylene in a proportion of 90% by mass or more, preferably 95% by mass or more, preferably 98% by mass or more with respect to the mass of the resin. The polypropylene-based resin is a resin containing polypropylene as a main component, and for example, polypropylene can be contained in a proportion of 90% by mass or more, preferably 95% by mass or more, and more preferably 98% by mass or more with respect to the mass of the resin.
More specifically, polyethylene is low density polyethylene (LDPE: Low Density Polyethylene), high density polyethylene (HDPE: High Density Polyethylene), ultra low density polyethylene (VLDPE: Very Low Density Polyethylene), linear low density polyethylene (linear low density polyethylene). LLDPE: Linear Low Density Polyethylene), or ultra high molecular weight polyethylene (UHMW-PE), or a combination of two or more of these.
More specifically, polypropylene may be homopolymer polypropylene or random copolymer or block copolymer polypropylene (eg, ethylene-propylene copolymer).

The polyolefin-based resin may preferably be a biomass-derived polyolefin-based resin, and may be, for example, biomass polyethylene and / or biomass polypropylene. Biomass polyethylene can be, for example, LDPE, LLDPE, or HDPE. By adopting a biomass-derived polyolefin resin as the polyolefin resin, CO2 emissions can be reduced.

The polyolefin-based resin may be a polyolefin-based resin produced by using a metallocene catalyst. For example, the polyolefin-based resin may be, for example, metallocene-catalyzed polyethylene or polypropylene, or a combination thereof.

The polystyrene-based resin is a resin containing polystyrene as a main component, and may contain, for example, polystyrene in a proportion of 90% by mass or more, preferably 95% by mass or more, preferably 98% by mass or more with respect to the mass of the resin. Examples of polystyrene include general-purpose polystyrene (GPPS) and impact-resistant polystyrene (HIPS).

The polyamide-based resin is a resin containing polyamide as a main component, and may contain, for example, polyamide in an amount of 90% by mass or more, preferably 95% by mass or more, preferably 98% by mass or more with respect to the mass of the resin. The polyamide may be, for example, an aliphatic polyamide, and more specifically, a polyamide 6, polyamide 6/6, polyamide 6/10, polyamide 11, polyamide 12, or polyamide 6/12.

The polyester-based resin is a resin containing polyester as a main component, and may contain, for example, 90% by mass or more, preferably 95% by mass or more, preferably 98% by mass or more of polyester with respect to the mass of the resin. Examples of polyesters include polyethylene terephthalate (hereinafter also referred to as PET), polybutylene succinate (hereinafter also referred to as PBS), polybutylene succinate adipate (hereinafter also referred to as PBSA), polybutylene terephthalate (hereinafter also referred to as PBAT), and polyhydroxy. Alkanic acid (hereinafter also referred to as PHA), polylactic acid (hereinafter also referred to as PLA), polybutylene terephthalate (hereinafter also referred to as PBT), polyethylene naphthalate (hereinafter also referred to as PEN), polyallylate (hereinafter also referred to as PAR), polycarbonate (hereinafter also referred to as PAR). (Hereinafter also referred to as PC), and one or a combination of two or more of these can be used as polyester.

In the present invention, the thermoplastic resin preferably has a melting point higher than the melting point of the second lubricant described below. That is, the thermoplastic resin has a melting point higher than the melting point of either the first lubricant or the second lubricant. Thereby, when producing the particles of the present invention, the materials can be mixed at a temperature at which the first lubricant and the second lubricant melt but the thermoplastic resin does not melt, and the material can be more easily mixed in the particle core portion. A cellulose powder-containing coating layer can be formed around the coating layer. The thermoplastic resin may have a melting point of preferably 110 ° C. to 250 ° C., more preferably 115 ° C. to 230 ° C., and even more preferably 120 ° C. to 210 ° C.

The particle core portion may preferably have a substantially spherical shape, more preferably a substantially spherical shape having a diameter of 2 mm to 9 mm, more preferably a substantially spherical shape having a diameter of 2 mm to 7 mm, and particularly preferably a substantially spherical shape having a diameter of 3 mm to 5 mm. .. By adopting the particle core portion having such a shape, it becomes easier to coat the cellulose powder over the entire particle core portion.
The particles of the present invention preferably have a substantially spherical morphology, more preferably a substantially spherical morphology having a diameter of 3 mm to 10 mm, and even more preferably a substantially spherical morphology having a diameter of 4 mm to 7 mm.
By having the above dimensions, each component can be easily mixed in the production of the resin composition described below, and the resin composition can be produced more easily.

The particle core portion may occupy preferably 20% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, and even more preferably 30% by mass to 70% by mass of the mass of the particles of the present invention. That is, the content of the thermoplastic resin constituting the particle core portion is preferably 20% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, and further more than the mass of the particles of the present invention. It can be preferably 30% by mass to 70% by mass.

1-2. Cellulose powder-containing coating layer

The cellulose powder-containing coating layer covers at least a part of the particle core portion, preferably covers an area of 80% or more, more preferably 90% or more of the surface of the particle core portion, and particularly preferably. It covers the entire surface of the particle core portion.

The cellulose powder-containing coating layer preferably contains a lubricant. With the lubricant, the cellulose powder constituting the coating layer can be attached to the surface of the particle core portion. The lubricant can reduce the friction between the resin composition and the molding machine and / or the friction between the particles. The lubricant can improve the fluidity and / or releasability of the resin composition.

According to a preferred embodiment of the present invention, the cellulose powder-containing coating layer comprises a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant. By including these two types of lubricants having different melting points, the cellulose powder can be easily attached to the particle core portion. The first lubricant may have a melting point of, for example, 50 ° C to 100 ° C, preferably 55 ° C to 90 ° C, more preferably 60 ° C to 80 ° C. The second lubricant may have, for example, a melting point of 100 ° C. to 160 ° C., preferably 100 ° C. to 150 ° C., more preferably 100 ° C. to 140 ° C.

As the first lubricant, for example, an ester-based lubricant can be mentioned, and in particular, an ester-based lubricant having a melting point within the numerical range described above can be used. Examples of the ester-based lubricant include glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, special fatty acid ester, and higher alcohol fatty acid ester. The glycerin fatty acid ester includes monoglyceride, diglyceride, triglyceride, acetylated monoglyceride, organic acid monoglyceride, and medium chain fatty acid monoglyceride.
According to a preferred embodiment of the present invention, the first lubricant comprises an ester-based lubricant, more preferably a glycerin fatty acid ester, and even more preferably a glycerin monostearate. The first lubricant may be only an ester-based lubricant, more preferably only a glycerin fatty acid ester, or even more preferably only a glycerin monostearate.

The second lubricant may contain at least one compound selected from the group consisting of fatty acid metal salts, hydrocarbons, higher alcohols, fatty amides, and fatty acid esters. The second lubricant is at least one compound selected from the group consisting of fatty acid metal salts, hydrocarbons, higher alcohols, fatty amides, and fatty acid esters, in particular having a melting point within the numerical range described above. Can be.
Examples of the fatty acid metal salt include metal salts of saturated or unsaturated fatty acids having 10 to 30 carbon atoms, particularly 12 to 25 carbon atoms. More specifically, the second lubricant is selected from the group consisting of magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, and sodium benzoate. Can be at least one species.

According to a particularly preferred embodiment of the present invention, the first lubricant may be the glycerin fatty acid ester and the second lubricant may be the fatty acid metal salt. By using these compounds as the first and second lubricants, the melt viscosity in extrusion for producing the resin composition from the particles of the present invention can be made more appropriate.

The content of the first lubricant in the particles may be, for example, 0.5 parts by mass to 5 parts by mass, preferably 1 part by mass to 4 parts by mass with respect to 100 parts by mass of the cellulose powder.
The content of the second lubricant in the particles may be, for example, 3 parts by mass to 20 parts by mass, preferably 5 parts by mass to 15 parts by mass with respect to 100 parts by mass of the cellulose powder. In particular, the content of the fatty acid metal salt in the particles may be, for example, 3 parts by mass to 20 parts by mass, preferably 5 parts by mass to 15 parts by mass with respect to 100 parts by mass of the cellulose powder.
Keeping the amounts of the first and second lubricants within the above-mentioned numerical ranges contributes to making the melt viscosity of the resin composition produced from the particles of the present invention suitable for molding.
Further, the fact that the amounts of the first and second lubricants are within the numerical ranges described above is suitable for the production of the particles of the present invention, that is, cellulose is formed on the surface of the particle core portion made of the thermoplastic resin. It becomes easier to attach the powder, that is, the particles of the present invention can be produced more efficiently.

The particle size D50 (median diameter) of the cellulose powder contained in the cellulose powder-containing coating layer can be, for example, 15 μm to 150 μm, and particularly preferably 20 μm to 100 μm. The particle size D50 is determined by wet measurement using a laser diffraction type particle size distribution measuring device (SALD-3100, Shimadzu Corporation). Cellulose powder having a particle size within the above numerical range is suitable for forming the particles of the present invention. Further, the fact that the cellulose powder has a particle size within the above numerical range can contribute to the improvement of the dispersibility of the cellulose powder in the resin composition of the present invention.

According to one preferred embodiment of the present invention, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is the number of all cellulose fibers constituting the cellulose powder. It accounts for 65% to 100%, preferably 70% to 100%, more preferably 80% to 100%, and even more preferably 85% to 100%. The above ratios regarding the number of cellulose fibers are the ratio of the number of cellulose fibers having a particle size of 0 μm to 9.8 μm (hereinafter referred to as “first ratio”) and 0 μm to the total number of cellulose fibers of the cellulose powder. The ratio of the number of cellulose fibers having a particle size of 110.6 μm (hereinafter referred to as “second ratio”) is determined by wet measurement using the laser diffraction type particle size distribution measuring device, and the second ratio is determined. It is obtained by subtracting the first ratio from. The numerical range "0 μm to 9.8 μm" and "0 μm to 110.6 μm" are both numerical ranges input to the laser diffraction type particle size distribution measuring device in the wet measurement.
In this embodiment, particularly preferably, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder is the number of all cellulose fibers constituting the cellulose powder. It accounts for 0% to 30%, preferably 0% to 25%, more preferably 0% to 20%, and even more preferably 0% to 15%. The above ratios regarding the number of cellulose fibers are the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm (the above-mentioned “second ratio”) and 0 μm to the total number of cellulose fibers of the cellulose powder. The ratio of the number of cellulose fibers having a particle size of 998.4 μm (hereinafter referred to as “third ratio”) was determined by wet measurement using the laser diffraction type particle size distribution measuring device, and the third ratio was determined. It is obtained by subtracting the second ratio from. The numerical range "0 μm to 110.6 μm" and "0 μm to 998.4 μm" are both numerical ranges input to the laser diffraction type particle size distribution measuring device in the wet measurement.
Cellulose powder having the above particle size distribution can be produced, for example, by treating pulp with a chemical such as an acid. Examples of the cellulose powder having the above particle size distribution include KC Flock W400 (Nippon Paper Industries, Ltd.).
The particles of the present invention can be used to mold films or sheets. In particular, by using the cellulose powder having the particle size distribution in this embodiment, better moldability (particularly molding in vacuum forming) when a thin molded product such as a film and a sheet is produced using the particles of the present invention. Gender) is brought.
In particular, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 80% to 100% of the total number of cellulose fibers constituting the cellulose powder. Even more preferably, by occupying 85% to 100%, it is possible to prevent the occurrence of tears or holes in the molded product obtained by subjecting the resin composition produced by using the particles of the present invention to vacuum molding. In order to prevent tearing or the occurrence of holes in the molded product, it is particularly preferable that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder constitutes the cellulose powder. It accounts for 0% to 20%, and even more preferably 0% to 15% of the total number of cellulose fibers.
As described above, the particles according to this embodiment are suitable for producing a resin composition for molding a film or sheet, that is, can be used for producing a film or sheet. The particles according to this embodiment may be used for injection molding.

According to another preferred embodiment of the present invention, the cellulose powder may have a particle size of 90% or more for a 100 mesh pass. In this embodiment, more preferably, the cellulose powder has a particle size of 90% or more in 100 mesh paths, and the apparent specific gravity of the cellulose powder is 0.30 g / ml to 0.40 g / ml. It is possible.

The particle size is measured by a standard sieving method, and specifically, it is measured as follows. That is, 10 g of a sample is placed in a 100 mesh standard sieve, a saucer and a lid are set in the standard sieve, and the sample is shaken with a low-tap type shaker for 40 minutes. Then, the particle size is determined by the following formula from the sample mass (10 g) and the mass of the sieve residue.
Particle size (%) = [(Sample mass (g) -Sieve residue (g)) / Sample mass (g)] x 100

The apparent density is measured as follows. That is, 10 g of the sample is precisely weighed with a balance and placed in a 50 ml graduated cylinder. To prevent the sample from scattering, hit the bottom of the graduated cylinder against a table on which a rubber sheet is laid. The tapping operation is continued until the sample is no longer clogged. After the tapping operation, the surface of the sample is flattened and its scale (volume, ml) is read. Then, the apparent density is calculated by the following formula.
Apparent specific gravity (g / ml) = sample (10 g) / volume (ml)

Cellulose powder having the above particle size (or the above particle size and the above apparent specific gravity) can be produced, for example, by mechanically pulverizing pulp (for example, jet mill pulverization). Examples of the cellulose powder having the above particle size (or the above particle size and the above apparent density) include KC floc 100 GK.
The particles of the present invention can be used for injection molding. In particular, by using a cellulose powder having the above particle size (or the above particle size and the above apparent density), good moldability is brought about when the particles of the present invention are subjected to injection molding. Further, the cellulose powder contributes to the improvement of the strength and / or heat resistance of the resin composition produced by using the particles of the present invention.

The total mass of the cellulose powder and the thermoplastic resin constituting the particles of the present invention is, for example, 70% by mass to 98% by mass, preferably 80% by mass to 97% by mass, more preferably with respect to the mass of the particles. Can be 85% by weight to 95%. When the total mass is within the range, the amount of the resin in the resin composition produced from the particles can be increased, and the content of the cellulose powder can be increased.

The cellulose powder-containing resin layer may further contain other components. Examples of the other components include compatibilizers and colorants.

The compatibilizer can be used to more uniformly disperse cellulose in the resin composition produced from the particles. The compatibilizer may be selected according to the type of the thermoplastic resin. Examples of the compatibilizer include acid-modified polyolefin, acid-modified nylon, acid-modified polystyrene, acid-modified EVA, acid-modified ethylene copolymer polymer, acid-modified acrylate, acrylic acid-modified EVA, and modified ethylene acrylate.

When the thermoplastic resin is a polyolefin-based resin, the compatibilizer is preferably an acid-modified polyolefin, and in particular, an anhydrous carboxylic acid-modified polyolefin or an olefin-based comonomer.
The carboxylic acid anhydride constituting the carboxylic acid anhydride-modified polyolefin can be preferably maleic anhydride. The compatibilizer is, for example, a maleic anhydride grafted polyolefin resin, and more particularly selected from the group consisting of maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and maleic anhydride-modified ethylene-propylene copolymer. It may be one or a combination of two or more. A rubber component may be dispersed in the compatibilizer.
The compatibilizer may be contained in the particles in a content ratio of, for example, 0.1 parts by mass to 10 parts by mass, more preferably 0.5 parts by mass to 6 parts by mass, per 100 parts by mass of the particles.

The colorant can be used to color the resin composition produced from the particles. Examples of the colorant include titanium oxide, carbon black, dyes, and pigments.

Further, as the other components, for example, an antioxidant and an impact resistant agent may be used. As the antioxidant, for example, a phenolic antioxidant can be used. The impact-resistant agent may be, for example, a styrene-based thermoplastic elastomer, and more specifically, for example, a styrene-ethylene-butylene-styrene block copolymer (SEBS) or a styrene-ethylene-ethylene-propylene-styrene block copolymer. (SEEPS) and styrene-ethylene-propylene-styrene block copolymer (SEPS).

1-3. Method for producing particles of the present invention

The method for producing particles of the present invention may include the following steps:
(1) The cellulose powder, the first lubricant, the second lubricant, and the thermoplastic resin to be the particle core portion are placed at a temperature equal to or higher than the melting point of the second lubricant and lower than the temperature of the thermoplastic resin. A mixing step of mixing to obtain a mixture containing the first lubricant and the melted second lubricant, the cellulose powder, and the thermoplastic resin; and (2) the mixture obtained in the mixing step. A cooling step of cooling with stirring to a temperature equal to or higher than the melting point of the first lubricant and lower than the melting point of the second lubricant.
In the cooling step, the second lubricant is solidified to form a cellulose powder-containing coating layer containing the first lubricant, the second lubricant, and the cellulose powder on the surface of the particle core portion. The particles of the present invention are obtained.
Each process will be described in more detail below.

(1) Mixing process

In the mixing step, the cellulose powder, the first lubricant, the second lubricant, and the thermoplastic resin serving as the particle core portion are mixed. In the mixing step, the above 1-2. Other components described in (eg, compatibilizers, colorants, antioxidants, impact resistant agents, etc.) may also be mixed.

The mixing step may be performed, for example, by a stirring device known in the art in which the mixing temperature can be set to the above temperature. As described above, the mixing step is performed at a temperature equal to or higher than the melting point of the second lubricant and lower than the temperature of the thermoplastic resin. The mixing step can be carried out, for example, at 100 ° C. to 160 ° C., preferably 100 ° C. to 150 ° C., and more preferably 100 ° C. to 140 ° C.

In the mixing step, by mixing at the above temperature, the first lubricant and the second lubricant melt, but the thermoplastic resin does not melt. In the mixing step, a state in which the cellulose powder, the solid thermoplastic resin, and the melted first lubricant and the second lubricant are mixed is formed.

The cooling step is performed so that the mixture obtained in the mixing step does not preferably have a temperature lower than the melting point of the second lubricant (particularly while maintaining the temperature adopted in the mixing step). Can be supplied to the device.

(2) Cooling process

In the cooling step, the mixture obtained in the mixing step can be cooled to a temperature equal to or higher than the melting point of the first lubricant and lower than the melting point of the second lubricant while being stirred. By cooling with stirring, a more uniform cellulose powder-containing coating layer is formed around the particle core portion, and the particles of the present invention can be obtained.

The cooling step can be performed by a stirring device capable of cooling the mixture obtained in the mixing step to a temperature equal to or higher than the melting point of the first lubricant and lower than the melting point of the second lubricant.

The particles of the present invention obtained by the above production method are preferably maintained at a temperature equal to or higher than the melting point of the first lubricant and lower than the melting point of the second lubricant. This makes it possible to prevent the cellulose powder from peeling off from the particles.

1-4. Method of using particles of the present invention

The particles of the present invention can be used, for example, to produce a resin composition containing a cellulose powder and a thermoplastic resin. For example, by heating and kneading the particles of the present invention above the melting point of the thermoplastic resin constituting the particles, a resin composition in which the cellulose powder constituting the particles is dispersed in the thermoplastic resin can be obtained. can get. By producing the resin composition using the particles of the present invention, it is possible to produce a resin composition in which cellulose powder is well dispersed. The resin composition obtained by using the particles of the present invention may be a resin composition according to the present invention described in "2. Resin composition" below.

2. 2. Resin composition

The resin composition of the present invention contains a thermoplastic resin and a cellulose powder, and the content ratio of the cellulose powder is 20% by mass to 50% by mass with respect to the mass of the resin composition. Further, the resin composition of the present invention further comprises a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant.

2-1. Composition of resin composition

The thermoplastic resin and cellulose powder contained in the resin composition of the present invention are as described in "1-1. Particle core portion" and "1-2. Cellulose powder-containing coating layer" above, and the description thereof is the present. This also applies to the resin compositions of the invention.

The content ratio of the cellulose powder in the resin composition of the present invention is 20% by mass to 50% by mass, preferably 22% by mass to 48% by mass, and more preferably 25% by mass with respect to the mass of the resin composition. It can be ~ 45% by weight.

The total mass of the cellulose powder and the thermoplastic resin contained in the resin composition of the present invention is, for example, 70% by mass to 98% by mass, preferably 80% by mass to 97% by mass, based on the mass of the resin composition. %, More preferably 85% by mass to 95% by mass. When the total mass is within the range, the amount of the resin in the resin composition can be increased, and the content of the cellulose powder can be further increased.

The ratio of the mass of the cellulose powder contained in the resin composition of the present invention to the mass of the thermoplastic resin is preferably 1: 1 to 1: 4, more preferably 1: 1 to 1: 3, and even more preferably. Can be 1: 1 to 1: 2.5. A ratio within the range can improve the dispersibility of the cellulose powder in the resin composition.

The resin composition of the present invention includes a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant. The first lubricant and the second lubricant are as described in "1-2. Cellulose powder-containing coating layer", and the description also applies to the resin composition of the present invention. According to a particularly preferred embodiment of the present invention, the first lubricant may be the glycerin fatty acid ester and the second lubricant may be the fatty acid metal salt.

The content of the first lubricant in the resin composition of the present invention is, for example, 0.5 parts by mass to 5 parts by mass, preferably 1 part to 4 parts by mass with respect to 100 parts by mass of the cellulose powder. It is possible.
The content of the second lubricant in the resin composition of the present invention may be, for example, 3 parts by mass to 20 parts by mass, preferably 5 parts by mass to 15 parts by mass with respect to 100 parts by mass of the cellulose powder. ..
Keeping the amounts of the first and second lubricants within the numerical ranges described above contributes to making the melt viscosity of the resin composition of the present invention suitable for molding.

The particle size D50 (median diameter) of the cellulose powder contained in the resin composition of the present invention can be, for example, 15 μm to 150 μm, and particularly preferably 20 μm to 100 μm. The particle size D50 is determined by wet measurement using a laser diffraction type particle size distribution measuring device (SALD-3100, Shimadzu Corporation). Using a cellulose powder having a particle size within the above numerical range can contribute to improving the dispersibility of the cellulose powder in the resin composition of the present invention.

According to one preferred embodiment of the present invention, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is the number of all cellulose fibers constituting the cellulose powder. It accounts for 65% to 100%, preferably 70% to 100%, more preferably 80% to 100%, and even more preferably 85% to 100%. The method for calculating the ratio of the number of cellulose fibers is as described in "1-2. Cellulose powder-containing coating layer" above.
In this embodiment, particularly preferably, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder is the number of all cellulose fibers constituting the cellulose powder. It accounts for 0% to 30%, preferably 0% to 25%, more preferably 0% to 20%, and even more preferably 0% to 15%. The method for calculating the ratio of the number of cellulose fibers is also as described in "1-2. Cellulose powder-containing coating layer" above.
By containing the cellulose powder having such a particle size distribution, the resin composition of the present invention has better moldability (particularly moldability in vacuum forming) when producing thin molded products such as films and sheets. Is brought.
In particular, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 80% to 100% of the total number of cellulose fibers constituting the cellulose powder. Even more preferably, by occupying 85% to 100%, it is possible to prevent the occurrence of tears or holes in the molded product obtained by subjecting the resin composition of the present invention to vacuum molding. In order to prevent tearing or the occurrence of holes in the molded product, it is particularly preferable that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder constitutes the cellulose powder. It accounts for 0% to 20%, and even more preferably 0% to 15% of the total number of cellulose fibers.
As described above, the resin composition of the present invention according to this embodiment can be used for molding a film or sheet.

According to another preferred embodiment of the present invention, the cellulose powder may have a particle size of 90% or more for a 100 mesh pass. In this embodiment, more preferably, the cellulose powder has a particle size of 90% or more in 100 mesh paths, and the apparent specific gravity of the cellulose powder is 0.30 g / ml to 0.40 g / ml. It is possible. The particle size and apparent specific gravity are measured as described in "1-2. Cellulose powder-containing coating layer" above.
By using a cellulose powder having the above particle size (or the above particle size and the above apparent density), good moldability is obtained when the resin composition of the present invention is subjected to injection molding. Further, the cellulose powder contributes to the improvement of the strength and / or heat resistance of the resin composition of the present invention.

The resin composition of the present invention may further contain other components. Examples of the other components include compatibilizers and colorants. The compatibilizer and colorant are as described in "1-2. Cellulose powder-containing coating layer" above. Further, as the other components, for example, an antioxidant and an impact resistant agent may be used.

The resin composition of the present invention can be used for molding a film or sheet. That is, the present invention also provides the resin composition of the present invention in the form of a film or sheet. The thickness of the film can be, for example, 10 μm to 500 μm, particularly 10 μm to 300 μm, and more particularly 10 μm to 200 μm. The thickness of the sheet can be, for example, 0.2 mm to 2 mm, particularly 0.3 mm to 1.5 mm, more particularly 0.4 mm to 1 mm.

2-2. Physical properties of resin composition

The resin composition of the present invention has a dimensional change rate of preferably −0.5% to + 0.5% when placed in an environment of a temperature of 23 ° C. and a humidity of 50% for 28 days, more preferably. It can be −0.4% to + 0.4%, more preferably −0.2% to + 0.2%. The dimensional change rate is a dimensional change rate in the long side direction of a resin composition having dimensions of 32 cm on the long side × 14 cm on the short side × 0.4 mm in thickness. As described above, the resin composition of the present invention has a low dimensional change rate.

The resin composition of the present invention has a flexural modulus of preferably 1.8 GPa or more, more preferably 1.8 GPa to 3 GPa, and even more preferably 2 GPa to 2.8 GPa when measured according to JIS K 7171. Can be. The flexural modulus is measured for a resin composition having dimensions of 8 cm on the long side × 1 cm on the short side × 0.5 cm in thickness. The resin composition of the present invention has such a flexural modulus, that is, has excellent rigidity.

The resin composition of the present invention has a deflection temperature under load preferably 100 ° C. or higher, more preferably 100 ° C. to 150 ° C., and even more preferably 105 ° C. to 130 ° C. when measured according to JIS K 7191. It is possible. The deflection temperature under load is measured for a resin composition having dimensions of 8 cm on the long side × 1 cm on the short side × 0.5 cm in thickness. The load in the measurement is 0.45 MPa. The resin composition of the present invention has such a deflection temperature under load, that is, has excellent heat resistance.

2-3. Method for manufacturing resin composition

The method for producing a resin composition of the present invention includes a kneading step of heating and kneading the particles of the present invention above the melting point of the thermoplastic resin forming the particle core portion of the particles. The kneaded product obtained by the kneading step is the resin composition of the present invention. The manufacturing method may further include a molding step of molding the resin composition obtained in the kneading step. The molded resin composition is also included in the resin composition of the present invention. The kneading process and the molding process will be described below.

(1) Kneading process

The particles of the present invention used in the kneading step are as described in "1. Particles" above, and the description also applies to the production method of the present invention. In the kneading step, the thermoplastic resin contained in the particles of the present invention is melted, and the cellulose powder contained in the cellulose powder-containing coating layer of the particles of the present invention is dispersed in the melted thermoplastic resin. .. Further, in the kneading step, the first lubricant and the second lubricant that can be contained in the particles of the present invention can also be melted and mixed with the thermoplastic resin.

Preferably, the particles of the present invention obtained in the cooling step described in "1-3. Method for producing particles of the present invention" are equal to or higher than the melting point of the first lubricant and the melting point of the second lubricant. It can be supplied to an apparatus (such as an extruder described below) for performing the kneading step while being maintained at a lower temperature.

The kneading step can be performed at a temperature at which the thermoplastic resin contained in the particles of the present invention can be melted. The temperature may be appropriately selected by those skilled in the art depending on the melting point of the thermoplastic resin used. The kneading step is carried out at, for example, 100 ° C. to 250 ° C., preferably 110 ° C. to 250 ° C., more preferably 115 ° C. to 230 ° C., still more preferably 120 ° C. to 210 ° C., and particularly preferably 120 ° C. to 190 ° C. It can be done.

The kneading step may be performed by, for example, a twin-screw kneading extruder or a uniaxial kneading extruder. Equipment known in the art may be used as these extruders. Preferably, the kneading step comprises at least heating and kneading with a twin-screw kneading extruder. As the twin-screw kneading extruder, a twin-screw kneading extruder that rotates in the same direction may be used, or a twin-screw kneading extruder that rotates in a different direction may be used. By performing the kneading treatment with a twin-screw kneading extruder, a resin composition in which the cellulose powder is more uniformly dispersed can be obtained.

The kneaded product obtained in the kneading step may be directly subjected to the molding step without being pelletized. As a result, the pelletization step can be omitted.
The kneaded product obtained in the kneading step may be pelletized. The pelletized resin composition may be subjected to a molding step.

(2) Molding process

In the molding step, the resin composition produced in the kneading step is molded. The resin composition of the present invention is suitable for molding a molded product having a thickness of, for example, 20 μm to 5 mm, that is, it can be used for molding the molded product.

In the molding step, the resin composition of the present invention can be molded into, for example, a film or a sheet. The thickness of the film or sheet can be, for example, 0.01 mm to 5 mm. Inflation molding can be performed to produce the film. The inflation molding can be performed using, for example, a ring die. Further, in order to manufacture the sheet, molding using a T-die can be performed. In these moldings, for example, the kneaded product may be extruded directly from these dies without being pelletized, or the pelletized resin composition is melted and the melted resin composition is It may be extruded from these dies.

Alternatively, in the molding step, the resin composition of the present invention can be molded by injection molding or vacuum forming. For example, the resin composition of the present invention can be molded into the shape of a container. The injection molding or vacuum forming can be used to form the shape of the container. In the injection molding, the resin composition of the present invention can be injected into a mold for imparting a desired shape (for example, a container) to the resin composition in a molten state. The resin composition is cooled in the mold to obtain a resin composition (molded product) having a desired shape. In the vacuum forming, the sheet is softened by heating, and the softened sheet is brought into close contact with a mold by suction to be formed.

2-4. Specific Examples of Resin Compositions

The resin composition of the present invention may be thermoplastic. Since the resin composition of the present invention is thermoplastic, molded articles having various shapes can be produced. More detailed specific examples of the composition and use of the resin composition according to the present invention will be described below.

(1) Thermoplastic resin composition for sheet molding

According to one embodiment of the present invention, the thermoplastic resin composition may include cellulose powder and polypropylene.
The cellulose powder is, for example, 10 parts by mass to 60 parts by mass, preferably 15 parts by mass to 55 parts by mass, more preferably 20 parts by mass to 50 parts by mass, and even more preferably 1 part by mass, per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of 25 parts by mass to 45 parts by mass.
The polypropylene is, for example, 30 parts by mass to 80 parts by mass, preferably 35 parts by mass to 75 parts by mass, more preferably 40 parts by mass to 70 parts by mass, and even more preferably 45 parts by mass, per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of parts by mass to 65 parts by mass.

Among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 65% to 100%, preferably 70% of the total number of cellulose fibers constituting the cellulose powder. It accounts for% to 100%, more preferably 80% to 100%, and even more preferably 85% to 100%. Particularly preferably, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm is 0% to 30% of the total number of cellulose fibers constituting the cellulose powder. It occupies 0% to 25%, more preferably 0% to 20%, and even more preferably 0% to 15%.

The resin composition may further contain a glycerin fatty acid ester as the first lubricant and a fatty acid metal salt as the second lubricant.
The glycerin fatty acid ester can be, for example, glycerin monostearate. The glycerin fatty acid ester is, for example, 0.3 parts by mass to 3 parts by mass, preferably 0.4 parts by mass to 2 parts by mass, and more preferably 0.5 parts by mass to 1 part by mass per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of .5 parts by mass.
The fatty acid metal salt is, for example, 2 parts by mass to 6 parts by mass, preferably 2.5 parts by mass to 5.5 parts by mass, and more preferably 3 parts by mass to 5 parts by mass per 100 parts by mass of the thermoplastic resin composition. Can be contained in the resin composition in the content ratio of.
Examples of the fatty acid metal salt include metal salts of saturated or unsaturated fatty acids having 10 to 30 carbon atoms, particularly 12 to 25 carbon atoms. More specifically, the second lubricant is selected from the group consisting of magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, and sodium benzoate. Can be at least one species.

The resin composition may further contain an impact resistant agent. The impact resistant agent may include a styrene-based thermoplastic elastomer. The impact resistant agent is, for example, 0.3 parts by mass to 3 parts by mass, preferably 0.4 parts by mass to 2 parts by mass, and more preferably 0.5 parts by mass to 1 part per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of .5 parts by mass.

The resin composition may further contain other components such as compatibilizers, antioxidants, and colorants. The compatibilizer may preferably include a maleic anhydride grafted polyolefin resin. The compatibilizer is, for example, 0.1 part by mass to 3 parts by mass, preferably 0.2 parts by mass to 2 parts by mass, and more preferably 0.5 parts by mass to 1 part per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of .5 parts by mass.

Thermoplastic resin compositions according to this embodiment are suitable for molding sheets, for example 0.2 mm to 2 mm, particularly 0.3 mm to 1.5 mm, more particularly 0.3 mm to 1.4 mm, and further. More particularly, it is used for molding a sheet having a thickness of 0.4 mm to 1 mm.
Since the thermoplastic resin composition according to this embodiment has excellent dispersibility of the cellulose powder, tearing or perforation is unlikely to occur even if an extremely thin sheet such as 0.2 mm to 0.4 mm is molded.
In addition, a thermoplastic resin composition according to this embodiment can be used for vacuum forming. By the vacuum forming, a molded product (for example, a container) having a desired shape can be manufactured.

(2) Thermoplastic resin composition for injection molding

According to other embodiments of the present invention, the thermoplastic resin composition may include cellulose powder and polypropylene.
The cellulose powder is, for example, 10 parts by mass to 60 parts by mass, preferably 15 parts by mass to 55 parts by mass, more preferably 20 parts by mass to 50 parts by mass, and even more preferably 1 part by mass, per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of 25 parts by mass to 45 parts by mass.
The polypropylene is, for example, 30 parts by mass to 80 parts by mass, preferably 35 parts by mass to 75 parts by mass, more preferably 40 parts by mass to 70 parts by mass, and even more preferably 45 parts by mass, per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of parts by mass to 65 parts by mass.

The cellulose powder may have a particle size of 90% or more for a 100 mesh pass. More preferably, the cellulose powder may have a particle size of 90% or more for a 100 mesh pass, and the apparent specific gravity of the cellulose powder may be 0.30 g / ml to 0.40 g / ml.

The resin composition may further contain a glycerin fatty acid ester as the first lubricant and a fatty acid metal salt as the second lubricant.
The glycerin fatty acid ester can be, for example, glycerin monostearate. The glycerin fatty acid ester is, for example, 0.3 parts by mass to 3 parts by mass, preferably 0.4 parts by mass to 2 parts by mass, and more preferably 0.5 parts by mass to 1 part by mass per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of .5 parts by mass.
The fatty acid metal salt is, for example, 2 parts by mass to 6 parts by mass, preferably 2.5 parts by mass to 5.5 parts by mass, and more preferably 3 parts by mass to 5 parts by mass per 100 parts by mass of the thermoplastic resin composition. Can be contained in the resin composition in the content ratio of.
Examples of the fatty acid metal salt include metal salts of saturated or unsaturated fatty acids having 10 to 30 carbon atoms, particularly 12 to 25 carbon atoms. More specifically, the second lubricant is selected from the group consisting of magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, and sodium benzoate. Can be at least one species.

The resin composition may further contain other components such as compatibilizers, antioxidants, and colorants. The compatibilizer may preferably include a maleic anhydride grafted polyolefin resin. The compatibilizer is, for example, 0.5 parts by mass to 5 parts by mass, preferably 1 part by mass to 4 parts by mass, and more preferably 1.5 parts by mass to 3.5 parts by mass per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of parts by mass.

The resin composition according to this embodiment is suitable for injection molding and can be used, for example, to form a container by injection molding.

(3) Thermoplastic resin composition for film molding

According to other embodiments of the present invention, the thermoplastic resin composition may include cellulose powder and polyethylene.
The cellulose powder is, for example, 10 parts by mass to 60 parts by mass, preferably 15 parts by mass to 55 parts by mass, more preferably 20 parts by mass to 50 parts by mass, and even more preferably 1 part by mass, per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of 25 parts by mass to 45 parts by mass.
The polyethylene is, for example, 30 parts by mass to 80 parts by mass, preferably 35 parts by mass to 75 parts by mass, more preferably 40 parts by mass to 70 parts by mass, and even more preferably 45 parts per 100 parts by mass of the thermoplastic resin composition. It is contained in the resin composition in a content ratio of parts by mass to 65 parts by mass.

Among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 65% to 100%, preferably 70% of the total number of cellulose fibers constituting the cellulose powder. It accounts for% to 100%, more preferably 80% to 100%, and even more preferably 85% to 100%. Particularly preferably, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm is 0% to 30% of the total number of cellulose fibers constituting the cellulose powder. It occupies 0% to 25%, more preferably 0% to 20%, and even more preferably 0% to 15%.

The resin composition may further contain a glycerin fatty acid ester as the first lubricant and a fatty acid metal salt as the second lubricant.
The glycerin fatty acid ester can be, for example, glycerin monostearate. The glycerin fatty acid ester is, for example, 0.1 part by mass to 1 part by mass, preferably 0.2 part by mass to 0.9 part by mass, more preferably 0.3 part by mass, per 100 parts by mass of the thermoplastic resin composition. It can be contained in the resin composition in a content ratio of ~ 0.8 parts by mass.
The fatty acid metal salt is contained in the resin composition in a content ratio of, for example, 1 part by mass to 3 parts by mass, preferably 1.5 parts by mass to 2.5 parts by mass, per 100 parts by mass of the thermoplastic resin composition. It can be.
Examples of the fatty acid metal salt include metal salts of saturated or unsaturated fatty acids having 10 to 30 carbon atoms, particularly 12 to 25 carbon atoms. More specifically, the second lubricant is selected from the group consisting of magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, and sodium benzoate. Can be at least one species.

The resin composition may further contain other components such as compatibilizers, antioxidants, and colorants. The compatibilizer may preferably include a maleic anhydride grafted polyolefin resin. The compatibilizer is contained in an amount of, for example, 1 part by mass to 10 parts by mass, preferably 3 parts by mass to 7 parts by mass, and more preferably 4 parts by mass to 6 parts by mass per 100 parts by mass of the thermoplastic resin composition. , May be included in the resin composition.

The thermoplastic resin composition according to this embodiment is suitable for molding a film by inflation molding, for example, 10 μm to 500 μm, particularly 10 μm to 300 μm, more particularly 10 μm to 200 μm, and even more particularly 60 μm to 100 μm. It is used to mold thick films.
Since the thermoplastic resin composition according to this embodiment has excellent dispersibility of the cellulose powder, even if an extremely thin film such as 50 μm to 100 μm is formed, tearing or perforation is unlikely to occur.

Hereinafter, the present invention will be described in more detail based on Examples. The examples described below are representative examples of the present invention, and the scope of the present invention is not limited to these examples.

Test Example 1: Production of a resin composition containing cellulose powder and evaluation of a sheet molded from the resin composition

(Example 1-1)

(Manufacturing of particles)

As shown in Table 1 below, 30 parts by mass of cellulose powder (KC Flock W400, Nippon Paper Industries, Ltd.), 59 parts by mass of polypropylene (PP, FL6632G, Sumitomo Chemical Co., Ltd.), glycerin fatty acid ester (S-100, RIKEN Vitamin) Co., Ltd.) 1 part by mass of fatty acid metal salt, 1 part by mass of impact resistant agent, 1 part by mass of compatibilizer, 1 part by mass of antioxidant, and 3 parts by mass of white MB were prepared. Table 2 below shows the ratio of the number of cellulose fibers having a particle size of 0 μm to 9.8 μm, the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm, and the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm, and 9.8 μm to 110. The percentage of the number of cellulose fibers having a particle size of 6 μm is shown. In Table 3 below, the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm, the ratio of the number of cellulose fibers having a particle size of 0 μm to 998.4 μm, and 110 of each cellulose powder. The percentage of the number of cellulose fibers having a particle size of .6 μm to 998.4 μm is shown. Further, the melting point of the fatty acid metal salt is higher than the melting point of the glycerin fatty acid ester. The ratios shown in Tables 2 and 3 were measured by wet measurement using a laser diffraction type particle size distribution measuring device (SALD-3100, Shimadzu Corporation).
Using these materials, particles in which polypropylene was coated with cellulose powder (hereinafter referred to as "particles of Example 1-1") were produced. The method for producing the particles will be described below.

(1) Mixing step In a stirrer (high temperature stirrer, Kawata Co., Ltd.), 30 parts by mass of cellulose powder, 59 parts by mass of polypropylene particles, 1 part by mass of glycerin fatty acid ester (first lubricant), fatty acid metal salt (metal). 4 parts by mass of soap, second lubricant), 1 part by mass of impact resistant agent, 1 part by mass of compatibilizer, 1 part by mass of antioxidant, and 3 parts by mass of white MB were mixed. The rotation speed of the stirring device in the mixing was 45 Hz. Further, the temperature of the stirring device was raised to 120 ° C. while performing the mixing. 120 ° C. is higher than both the melting point of the glycerin fatty acid ester and the melting point of the fatty acid metal, and is lower than the melting point of the polypropylene. In the mixing, the glycerin fatty acid ester and the fatty acid metal were melted and these lubricants were spread throughout the cellulose powder and polypropylene particles.

(2) Cooling step The high-temperature mixture obtained in the mixing step is put into a coolable stirrer (cooling stirrer, Kawata Co., Ltd.), and 70 while stirring at a rotation speed of 25 Hz in the stirrer. Cooled to ° C. 70 ° C. is higher than the melting point of the glycerin fatty acid ester and lower than the melting point of the fatty acid metal. By the cooling with stirring, particles (particles of Example 1-1) in which the polypropylene particle core portion was coated with the cellulose powder-containing coating layer were obtained.
The particles were transferred into a stock tank and maintained at about 70 ° C.

(Manufacturing of resin composition)

While heating the particles of Example 1-1 maintained at about 70 ° C. in the stock tank to a temperature higher than the melting point of the thermoplastic resin (polypropylene) contained in the particles using a kneading extruder. The mixture was kneaded to obtain a resin composition (hereinafter, also referred to as “resin composition of Example 1-1”). The cylinder temperature in the kneading was 160 ° C to 200 ° C. The resin composition was extruded from a T-die provided in the kneading extruder and formed into a sheet. The obtained sheet-shaped resin composition was picked up by a pick-up roll. The sheet-shaped resin composition was cooled in the taking-up process. The thickness of the sheet-shaped resin composition after cooling (hereinafter, also referred to as “sheet of Example 1-1”) was 0.5 mm. The sheet of Example 1-1 was excellent in rigidity, heat resistance, and dimensional stability.

(Examples 1-2 to 1-6)

A sheet formed from the resin composition was produced by the same method as in Example 1-1 except that the cellulose powder shown in Table 2 below was used as the cellulose powder instead of KC flocs. The sheets of each embodiment are referred to as "sheets of Example 1-2" and "sheets of Example 1-3" in the same manner as the sheets of Example 1-1. All of the sheets of Examples 1-2 to 1-6 were excellent in rigidity, heat resistance, and dimensional stability.
Table 2 also shows the ratio of the number of cellulose fibers having a particle size of 0 μm to 9.8 μm, the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm, and 9.8 μm of each cellulose powder. The percentage of the number of cellulose fibers having a particle size of ~ 110.6 μm is shown. In Table 3 below, the ratio of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm, the ratio of the number of cellulose fibers having a particle size of 0 μm to 998.4 μm, and 110 of each cellulose powder. The ratio of the number of cellulose fibers having a particle size of 6.6 μm to 998.4 μm is shown.

Vacuum forming was performed using each of the sheets of Examples 1-1 to 1-6. The vacuum forming was performed as follows. That is, each sheet was heated and softened by heating for about 25 seconds in a vacuum forming apparatus (FVS-500P, Wakisaka Engineering Co., Ltd.) set at 450 ° C., and the softened sheet was formed by the apparatus. The mold used in the molding had a rectangular parallelepiped shape having dimensions of 9.7 cm in length, 9.7 cm in width, and 3.0 cm in height. In the molding, a container having a length of 9.7 cm, a width of 9.7 cm, and a depth of 3.0 cm was molded.

The formability of each sheet (whether it could be applied to vacuum forming) and the molded product formed from each sheet by vacuum forming were evaluated according to the following evaluation criteria.
<Moldability>
Possible: Applicable (molded product had a shape according to the mold)
Impossible: Not applicable (many holes, molded part did not have a shape that conforms to the mold)
<Evaluation of molded products>
A: A molded product having a smooth surface and no holes or tears B: A molded product having a slightly rough surface and slightly holes C: A rough surface It was a molded product with holes

The evaluation results are shown in Table 4 below.

As shown in Table 4, all of the sheets of Example 1-1, Example 1-2, Example 1-4, and Example 1-6 could be applied to vacuum forming, but Examples. Sheets 1-3 and 1-5 could not be applied to vacuum forming. From this result, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 65% to 100%, preferably 70% to 100% of the total number of cellulose fibers constituting the cellulose powder. It can be seen from this that the resin composition of the present invention is excellent in moldability for vacuum forming.
More particularly, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm is 0% to 30%, preferably 0% to 25% of the total number of cellulose fibers constituting the cellulose powder. It can be seen that a particularly excellent molded product can be obtained.

Further, among Examples 1-1 to 1-6, in Example 1-1, the evaluation result of the molded product was A, and a particularly excellent molded product could be molded. From this result, among the particles of the present invention, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm is 80% to 100%, more preferably 100% of the total number of cellulose fibers constituting the cellulose powder. It can be seen that a particularly excellent molded product can be obtained by using the cellulose powder which accounts for 85% to 100%.
More specifically, among the cellulose fibers constituting the cellulose powder, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm is 0% to 20% of the total number of cellulose fibers constituting the cellulose powder. It can be seen that a particularly excellent molded product can be obtained by using a cellulose powder that occupies 0% to 15% more preferably.

Test Example 2: Change in the ratio of thermoplastic resin and cellulose powder

(Example 2-1)

As shown in Table 5 below, a sheet formed from the resin composition by the same method as in Example 1-1 except that the amount of cellulose powder is 40 parts by mass and the amount of polypropylene is 49 parts by mass (hereinafter, , "Sheet of Example 2-1") was manufactured.

The sheet of Example 2-1 could also be applied to vacuum forming. Moreover, when the sheet of Example 2-1 was evaluated according to the evaluation criteria described in Test Example 1 above, it was evaluated as A.

From the viewpoint of ease of producing particles, Example 1-1 was superior to Example 2-1. It is considered that this is because the amount of lubricant (particularly the amount of the second lubricant) relative to the amount of cellulose powder in Example 1-1 was larger than that in Example 2-1. Therefore, the content of the second lubricant (particularly the fatty acid metal salt) in the particles of the present invention (or the resin composition of the present invention) is preferably more than 10 parts by mass with respect to 100 parts by mass of the cellulose powder. , More preferably 11 parts by mass or more.

Test Example 3: Production of resin composition and evaluation of sheet molded from the resin composition

(Example 3)

As shown in the column of Example 3 in Table 6 below, 30 parts by mass of cellulose powder (KC Flock 100 GK, Nippon Paper Industries, Ltd.), 62.5 parts by mass of polypropylene (Homopropylene, J108M, Prime Polymer Co., Ltd.), fatty acids 4 parts by mass of the metal salt and 2.5 parts by mass of the compatibilizer were prepared. These materials were mixed and pelletized using a twin-screw extruder. The kneading temperature was about 140 ° C. and the rotation speed was 12 rpm. From the obtained pellets, using an injection molding machine (injection molding machine, Sumitomo Heavy Industries, Ltd.), the shape of the test piece used in the following flexural modulus evaluation, deflection temperature under load evaluation, and dimensional stability evaluation Injection molded. The thickness of the test piece was 1.0 mm. In the injection molding, the temperature for melting the pellets was 170 ° C.

(Comparative Example 3)

Polypropylene (Homopropylene, J108M, Prime Polymer Co., Ltd.) was injection-molded into the shape of a test piece by injection molding in the same manner as in Example 3.

(Evaluation)

(1) Evaluation of flexural modulus The flexural modulus of the sheet of Example 3 and the sheet of Comparative Example 3 were measured. The measurement was performed according to JIS K 7171. The test piece used for the measurement had dimensions of 8 cm on the long side × 1 cm on the short side × 0.5 cm in thickness. The measurement results are shown in FIG. As shown in FIG. 2, the sheet of Example 3 had a higher flexural modulus than the sheet of Comparative Example 3. From this result, it can be seen that the rigidity of the sheet is improved by containing the cellulose powder.
Further, the polyolefin-based resin composition containing a biomass material tends to have lower rigidity (bending elastic modulus) than the polyolefin-based resin composition containing no biomass material. However, by adopting cellulose powder as the biomass material, It can be seen that the rigidity is improved.

(2) Evaluation of Deflection Temperature Under Load The deflection temperature under load on the sheet of Example 3 and the sheet of Comparative Example 3 was measured. The measurement was performed flatwise according to JIS K 7191 with a load of 0.45 MPa in weight. The test piece used for the measurement had dimensions of 8 cm on the long side × 1 cm on the short side × 0.5 cm in thickness. The measurement results are shown in FIG. As shown in FIG. 3, the sheet of Example 3 had a higher deflection temperature under load than the sheet of Comparative Example 3. From this result, it can be seen that the heat resistance of the sheet is improved by containing the cellulose powder.
Further, the polyolefin-based resin composition containing a biomass material tends to have lower heat resistance (deflection temperature under load) than the polyolefin-based resin composition not containing a biomass material, but cellulose powder should be adopted as the biomass material. It can be seen that the heat resistance is improved.

(3) Evaluation of dimensional stability The dimensional stability of the sheet of Example 3 was evaluated. The test piece used in the evaluation had dimensions of 32 cm on the long side × 14 cm on the short side × 0.4 mm in thickness. In this evaluation, the dimensions in the long side direction when the sheet of Example 3 was left under the conditions of a temperature of 23 degrees and a humidity of 50% for 30 days were measured, and the dimensional change rate was calculated from the measured dimensions. The dimensional change rate is the dimensional change rate (%) calculated by the following formula = [L _{1 −} L ₀ ] / L ₀ × 100.
Here, L ₁ is a dimension measured after leaving, and L ₀ is a dimension before starting leaving.
The measurement result of the dimensional change rate is shown in FIG. As shown in FIG. 4, the dimensional change rate of the sheet of Example 3 (legend “30%” in FIG. 4) was in the range of −0.2% to + 0.2% over the 30 days. .. From this result, it can be seen that the sheet of Example 3 is excellent in dimensional stability.
The content ratio of the cellulose powder in the sheet of Example 3 is 30% by mass, but even when this ratio is set to 40% by mass (the legend "40%" in FIG. 4), over the 30 days,- It was in the range of 0.2% to + 0.2%. From this result, it can be seen that the dimensional stability is excellent even when the content ratio of the cellulose powder is 40% by mass.
Further, the polyolefin-based resin composition containing the biomass material tends to be inferior in dimensional stability to the polyolefin-based resin composition not containing the biomass material, but it is more excellent by adopting the cellulose powder as the biomass material. It can be seen that the dimensional stability is improved.

Claims (13)

A particle composed of a particle core portion made of a thermoplastic resin and a cellulose powder-containing coating layer covering at least a part of the particle core portion. Claimed that the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm among the cellulose fibers constituting the cellulose powder accounts for 65% to 100% of the total number of cellulose fibers constituting the cellulose powder. Item 2. The particle according to Item 1. Claimed that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder accounts for 0% to 30% of the total number of cellulose fibers constituting the cellulose powder. Item 2. The particle according to Item 1 or 2. The particle according to any one of claims 1 to 3, which is used for molding a film or a sheet. The particle according to claim 1, wherein the cellulose powder has a particle size of 90% or more in 100 mesh paths. The particle according to any one of claims 1 to 5 used for injection molding. The particle according to any one of claims 1 to 6, wherein the coating layer contains a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant. The particle according to claim 7, wherein the second lubricant comprises at least one compound selected from the group consisting of fatty acid metal salts, hydrocarbons, higher alcohols, fatty amides, and fatty acid esters. The particles according to claim 7 or 8, wherein the first lubricant contains a glycerin fatty acid ester. The particle according to any one of claims 1 to 9, wherein the particle has a substantially spherical shape having a diameter of 3 mm to 10 mm. Contains thermoplastic resin and cellulose powder
The content ratio of the cellulose powder is 20% by mass to 50% by mass with respect to the mass of the resin composition.
Further comprising a first lubricant and a second lubricant having a melting point higher than the melting point of the first lubricant.
Resin composition. Claimed that the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm among the cellulose fibers constituting the cellulose powder accounts for 65% to 100% of the total number of cellulose fibers constituting the cellulose powder. Item 2. The resin composition according to Item 11. The resin composition according to claim 11, wherein the cellulose powder has a particle size of 90% or more in 100 mesh paths.