JP7199812B2 - Cellulose fiber dispersant, resin composition, method for producing resin composition, and molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cellulose fiber dispersant, a resin composition, a method for producing a resin composition, and a molded article.

Cellulose fibers are light weight, have a high modulus of elasticity, and have high strength, so they are attracting attention as reinforcing materials for resins. However, since it has many hydroxyl groups in its molecular chain, it is highly hydrophilic, and when heated, the water between the fibers evaporates and self-aggregates easily. Therefore, it is difficult to disperse them uniformly in the resin. In particular, cellulose nanofibers that have been defibrated to the nano level tend to aggregate during drying, and aggregates tend to remain in the composite material when combined with a resin.

Various attempts have been made to solve the above problems.
Patent Document 1 discloses a thermoplastic resin composition containing a thermoplastic resin, vegetable fibers, a rosin-based resin and a vegetable oil.
Patent Document 2 discloses a natural fiber composite composition composed mainly of natural fibers, a thermoplastic polymer and a dispersing resin.
Patent Document 3 discloses a cellulose fiber/resin composite composition obtained by a specific manufacturing method.
In addition, cellulose nanofibers have little affinity with nonpolar resins such as polypropylene, and there are almost no examples of uniformly dispersing cellulose nanofibers in polypropylene without chemical modification.

Japanese Patent Application Laid-Open No. 2002-294080 JP 2012-111855 A JP 2015-183153 A

Since conventional resin compositions have insufficient fiber dispersibility, there have been problems such as fiber aggregation and effects (improved mechanical properties, etc.) due to the addition of fibers being not sufficiently exhibited. Further, in some cases, a fiber dispersing step or the like is further provided in order to improve the dispersibility, but this is not economical.
An object of the present invention is to provide a cellulose fiber dispersant capable of sufficiently dispersing cellulose fibers in a resin, and a resin composition capable of producing a molded article having high mechanical properties.

As a result of intensive studies by the present inventors, it was found that the use of a rosin compound having specific physical properties enables the cellulose fibers to be sufficiently dispersed in the resin, and that the resin composition using the rosin compound has excellent mechanical properties. The present invention was completed by discovering that the body can be obtained.
According to the present invention, the following resin composition and the like are provided.
1. A cellulose fiber dispersant containing an acid-modified rosin having an acid-modified rate of 0.08 to 4.0% by mass.
2. 2. The cellulose fiber dispersant according to 1, wherein the acid-modified rosin is an α,β-unsaturated dicarboxylic acid-modified rosin.
3. A first resin composition containing the following components (A) and (B) in the following proportions.
(A) 0.1 to 99.9% by mass of the cellulose fiber dispersant according to 1 or 2
(B) Cellulose fiber 0.1 to 99.9% by mass
4. 3. The resin composition according to 3, wherein the cellulose fibers of component (B) have an average fiber diameter of 3 nm to 50 μm.
5. 5. The resin composition according to 3 or 4, wherein the component (B) is a plant-derived cellulose fiber.
6. A second resin composition containing the following components (A) to (C) in the following proportions.
(A) 0.01 to 89.0% by mass of cellulose fiber dispersant according to 1 or 2
(B) Cellulose fiber 0.05 to 80.0% by mass
(C) thermoplastic resin 10.0 to 99.9% by mass
7. 7. The resin composition according to 6, wherein the cellulose fibers of component (B) have an average fiber diameter of 3 nm to 50 μm.
8. 8. The resin composition according to 6 or 7, wherein the component (B) is a plant-derived cellulose fiber.
9. 9. The resin composition according to any one of 6 to 8, wherein the component (C) is a polyolefin resin.
10. 9. The resin composition according to any one of 6 to 9, wherein the component (C) is polypropylene.
11. 11. The resin composition according to any one of 6 to 10, wherein the component (C) has a melt flow rate of 0.1 to 200 g/10 minutes at 230° C. and a load of 2.16 kg.
12. The content of component (A) is 0.01 to 50.0% by mass, the content of component (B) is 0.05 to 50.0% by mass, and the content of component (C) is The resin composition according to any one of 6 to 11, wherein is 20.0 to 99.9% by mass.
13. a step of kneading cellulose fibers containing water and a cellulose fiber dispersant containing an acid-modified rosin having an acid-modified rate of 0.08 to 4.0% by mass;
A method for producing a resin composition, comprising the step of melt-kneading the mixture obtained in the above step and a thermoplastic resin.
14. A molded article produced using the resin composition according to any one of 6 to 12.

ADVANTAGE OF THE INVENTION According to this invention, the cellulose fiber dispersing agent which can fully disperse|distribute a cellulose fiber in resin, and the resin composition which can manufacture a molded object with high mechanical property can be provided.

Embodiments of the present invention will be described below. In this specification, "x to y" represents a numerical range of "x or more and y or less".

[Cellulose fiber dispersant]
A cellulose fiber dispersant according to one aspect of the present invention contains an acid-modified rosin having an acid-modified rate of 0.08 to 4.0% by mass.
Cellulose fiber dispersants have a high affinity with cellulose fibers, thermoplastic resins and water. That is, it has a function as a hydrophobizing agent capable of hydrophobizing cellulose fibers, and can uniformly disperse the cellulose fibers in the resin composition. In addition, aggregation of cellulose fibers can be suppressed. As will be described later, the use of a resin composition containing the cellulose fiber dispersant provides a molded article having high mechanical properties.

Acid-modified rosin is a compound obtained by modifying rosin with an acid such as α,β-unsaturated carboxylic acid. Acid-modified rosin can be obtained, for example, by a Diels-Alder reaction between rosin and α,β-unsaturated carboxylic acid.

Rosin is obtained as a solid hydrocarbon or the like secreted from trees such as conifers (for example, pine), and is a substance containing a resin acid having a reactive double bond. A resin acid is a compound having a tree-derived carboxyl group, and specific examples of the resin acid having a reactive double bond include abietic acid, parastric acid, neoabietic acid, and levopimaric acid.
When rosin is reacted with an α,β-unsaturated carboxylic acid, the reactive double bond in the resin acid of the rosin and the α,β-unsaturated carboxylic acid undergo a Diels-Alder reaction to form an acid modified product. can get.

The rosin may be unmodified rosin (unmodified rosin) that has not been subjected to modification treatment such as disproportionation treatment, hydrogenation (hydrogenation) treatment, petroleum resin modification treatment, polymerization treatment, or the like. It may be a modified rosin that has been subjected to one or more of them.
Examples of non-denatured rosins include tall oil rosin, gum rosin, wood rosin and the like, preferably gum rosin.
One type of rosin may be used alone, or two or more types may be used in combination.

Examples of α,β-unsaturated carboxylic acids include α,β-unsaturated monocarboxylic acids and α,β-unsaturated dicarboxylic acids. α,β-unsaturated monocarboxylic acids include acrylic acid and methacrylic acid, and α,β-unsaturated dicarboxylic acids include fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid and anhydride. and citraconic acid. From the viewpoint of addition reaction with rosin, α,β-unsaturated dicarboxylic acids are preferred, and fumaric acid, maleic acid and maleic anhydride are more preferred.
The α,β-unsaturated carboxylic acids may be used singly or in combination of two or more.

The mixing ratio of rosin and α,β-unsaturated carboxylic acid is, for example, 1 mol or less of α,β-unsaturated carboxylic acid per 1 mol of rosin.
The reaction temperature of rosin and α,β-unsaturated carboxylic acid is, for example, 150 to 300° C., and the reaction time is, for example, 1 to 24 hours. In this reaction, if necessary, a known catalyst can be blended in an appropriate proportion.
An acid-modified rosin having a predetermined acid modification rate can be obtained by appropriately adjusting the mixing ratio, reaction temperature, and reaction time described above.

Examples of the acid-modified rosin include α,β-unsaturated dicarboxylic acid-modified rosin modified with α,β-unsaturated dicarboxylic acid, preferably fumaric acid-modified rosin modified with fumaric acid ( fumarated rosin), maleic acid-modified rosin modified with maleic acid or maleic anhydride (maleated rosin), more preferably maleic acid-modified rosin.
Acid-modified rosin may be used alone or in combination of two or more.

The acid modification rate of the acid-modified rosin is 0.08% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, still more preferably 2.0% by mass or more, and particularly preferably 2.0% by mass or more. .5% by mass or more.
The acid modification rate of the acid-modified rosin is 4.0% by mass or less, preferably 3.7% by mass or less, more preferably 3.4% by mass or less, even more preferably 3.2% by mass or less, and particularly preferably 3.0% by mass or less. .1% by mass or less.

The acid modification rate is the mass ratio of the acid used for modification to the starting rosin (modified rosin or unmodified rosin), and is calculated by (mass of acid/mass of starting rosin)×100.

The acid modification rate of acid-modified rosin is measured as follows.
A small amount of acid-modified rosin and one drop of tetramethylammonium hydroxide are placed in a pyrolysis furnace, thermally decomposed, transferred to a connected gas chromatography, and gas chromatography analysis is performed under the following conditions. From the decomposition peak, the acid-denaturation rate is calculated from the area ratio of the rosin portion and the acid-denatured portion.
・Model used: Gas chromatography “Agilent 7890A” (manufactured by Agilent Technologies)
・ Pyrolysis furnace: “PY3030S” (manufactured by Frontier Lab Co., Ltd.)
・ Gas chromatography (GC) operating conditions Column: UA-5 (30 m / 0.25 μm)
Temperature: 150-250°C (held for 20 minutes), 4°C/min Inlet/FID: 250°C
Split ratio: 60/1
Helium flow rate: 1 ml/min Pyrolysis furnace operating conditions Pyrolysis furnace temperature: 500°C
Interface temperature: 320°C

As the acid-modified rosin, an acid-modified rosin ester obtained by esterifying an acid-modified rosin may be used. An acid-modified rosin ester is preferable in terms of heat resistance because it has an improved softening point. The acid-modified rosin ester can be obtained by esterifying an acid-modified rosin and a polyhydric alcohol by a known esterification method.

Polyhydric alcohols include dihydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylene glycol, tetramethylene glycol, 1,3-butanediol and 1,6-hexanediol; trihydric alcohols such as methylolethane and triethylolethane; tetrahydric alcohols such as pentaerythritol and diglycerin; hexahydric alcohols such as dipentaerythritol; triethanolamine, tripropanolamine, triisopropanolamine, N-isobutyldiethanolamine, N - aminoalcohols such as normal-butyldiethanolamine; The blending amount of the polyhydric alcohol is not particularly limited, and may be set as appropriate.

As the acid-modified rosin ester, an ester obtained without using an epoxy compound is preferred.

The acid-modified rosin may be liquid or solid, but is preferably solid at 25°C. If it is solid, the resin composition can be prepared simply and inexpensively in a small number of steps, which is economical.

The cellulose fiber dispersant according to one aspect of the present invention may contain other additives (eg, phenolic antioxidants, phosphorus antioxidants, sulfur-based lightening agents, etc.).
For example, 70% by mass or more, 80% by mass or more, 90% by mass or more, 98% by mass or more, 99% by mass or more, or 99.9% by mass or more of the cellulose fiber dispersant is the above acid-modified rosin. good too. The cellulose fiber dispersant may consist essentially of the acid-modified rosin described above. In this case, it may contain unavoidable impurities. The cellulose fiber dispersant may consist only of the above acid-modified rosin.

[First resin composition]
A resin composition (first resin composition) according to one aspect of the present invention contains the following components (A) and (B) in the following proportions.
(A) cellulose fiber dispersant 0.1 to 99.9% by mass
(B) Cellulose fiber 0.1 to 99.9% by mass

The first resin composition is a resin composition obtained by previously mixing the cellulose fiber dispersant and the cellulose fibers before kneading with the thermoplastic resin. As will be described later, by kneading these components once and then kneading them with the thermoplastic resin, the cellulose fibers can be more uniformly dispersed in the thermoplastic resin.

The cellulose fiber dispersant of component (A) is as described above.
The cellulose fiber of component (B) is not particularly limited, and various known ones can be used. Specifically, plant-derived cellulose fibers separated from plants such as plant-derived pulp, wood, bamboo, hemp, cotton, coconut, rice straw, and seaweed; cellulose fibers produced by marine animals such as sea squirts; produced by acetic acid bacteria cellulose fibers obtained from waste paper and the like; and chemically synthesized cellulose fibers such as cellulose acetate, cellulose nitrate, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and rayon.
Among these, plant-derived cellulose fibers are preferable, and cellulose fibers obtained from plant-derived pulp (plant pulp-derived cellulose fibers) are more preferable from the viewpoint of raw material productivity, mechanical strength of fibers, and impurities.

As plant-derived pulp, general-purpose pulp such as kraft pulp, sulfite pulp, thermomechanical pulp, and mechanical pulp can be used. Broad-leaved trees, coniferous trees, bamboo and the like can be used as the raw material. In particular, it is preferable to use pulp having an α-cellulose content of 60 to 99% by mass. If the purity has an α-cellulose content of 60% by mass or more, the fiber diameter and fiber length can be easily adjusted, and entanglement between fibers can be suppressed. The effect of suppressing coloring is better than in the case. In addition, if the α-cellulose content is 99% by mass or less, the fibers can be easily defibrated to the nano level.
The α-cellulose content of pulp is measured according to JIS P 8101 (1976).

The method for producing cellulose fibers is not particularly limited, and known methods can be used. For example, an underwater counter-impingement method in which particles are dispersed in water and are subjected to counter-collision under high pressure, a grinder method in which particles are ground between rotating grindstones, a homogenizer, a high-pressure collision-type pulverizer, a ball mill, a roll mill, a cutter mill, an ultrasonic disperser, or the like is used. A method using mechanical processing such as a miniaturization method can be mentioned. Moreover, it may be manufactured by defibrating by chemical treatment such as enzyme treatment or acid treatment.
A cellulose fiber may be used individually by 1 type, and may use 2 or more types together.

The average fiber diameter of the cellulose fibers is preferably 3 nm or more, more preferably 5 nm or more, still more preferably 10 nm or more, particularly preferably 20 nm or more, preferably 50 μm or less, more preferably 45 μm or less, further preferably 40 μm or less, Especially preferably, it is 35 μm or less.
An average fiber diameter of 3 nm to 50 μm is preferable from the viewpoint of the mechanical properties of the resin composition and the surface appearance of the molded article.
The average fiber diameter is 1 mm. 100 fibers with a fiber diameter of 1 nm to 100 μm in a ^square area are randomly selected by visual inspection using a photograph taken with an electron microscope ("Tecnai Osiris" manufactured by FEI), and the 100 Calculated by calculating the simple average (arithmetic average) of the fiber diameters of the individual. As for the fiber diameter, the length of the fiber is used.

The average degree of polymerization of the cellulose fiber is preferably 200 or more, more preferably 300 or more, still more preferably 500 or more, preferably 10,000 or less, more preferably 5,000 or less, and still more preferably 3,000 or less. be.
An average degree of polymerization of 200 to 10,000 is preferable from the viewpoint of mechanical properties and workability of the resin composition. When using cellulose fibers with a degree of polymerization of more than 10,000, the viscosity of the resin composition may increase and workability may deteriorate.
The average degree of polymerization is measured by the copper ethylenediamine method (the cellulose fiber should be delignified and have a purity of 80% or higher).

The content of component (A) in the first resin composition is 0.1% by mass or more, preferably 5.0% by mass or more, more preferably 10.0% by mass or more, and still more preferably 15.0% by mass. It is at least 20.0% by mass, particularly preferably at least 20.0% by mass.
The content of component (A) in the first resin composition is 99.9% by mass or less, preferably 95.0% by mass or less, more preferably 90.0% by mass or less, and still more preferably 85.0% by mass. % by mass or less, particularly preferably 80.0 mass % or less.

The content of component (B) in the first resin composition is 0.1% by mass or more, preferably 5.0% by mass or more, more preferably 10.0% by mass or more, and still more preferably 15.0% by mass. It is at least 20.0% by mass, particularly preferably at least 20.0% by mass.
The content of component (B) in the first resin composition is 99.9% by mass or less, preferably 95.0% by mass or less, more preferably 90.0% by mass or less, and still more preferably 85.0% by mass. % by mass or less, particularly preferably 80.0 mass % or less.

The first resin composition can be produced by mixing the above components (A) and (B). There are no particular restrictions on the mixing method.

When the components (A) and (B) are mixed, it is preferable that the cellulose fibers of the component (B) are moistened (or dispersed in water). In this way, by substituting the component (A) for the water content between the cellulose fibers, aggregation of the cellulose fibers during drying can be suppressed. Moisture is typically expelled as steam or waste water during mixing.

The above water content is, for example, 10.0% by mass or more, preferably 20.0% by mass or more, more preferably 30.0% by mass or more, based on the total of cellulose fibers and water. It is preferably 50.0% by mass or more, and particularly preferably 60.0% by mass or more. If the water content is 10.0% by mass or more, the hydrogen bonds between the cellulose fibers are moderately relaxed, so that the cellulose fibers can be easily dispersed.

In addition, the water content is, for example, 99.0% by mass or less, preferably 95.0% by mass or less, and more preferably 90.0% by mass or less, relative to the total of cellulose fibers and water. , more preferably 85.0% by mass or less, and particularly preferably 80.0% by mass or less. If the water content is 99.0% by mass or less, it is possible to suppress the outflow, denaturation, and deterioration of the component (A) together with the water. Moreover, deterioration of equipment can be suppressed. Furthermore, the productivity is excellent because the solid content in the mixed system is appropriate.

The first resin composition may contain other additives (for example, phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based lightening agents, etc.).

For example, 70% by mass or more, 80% by mass or more, 90% by mass or more, 98% by mass or more, 99% by mass or more, or 99.9% by mass or more of the first resin composition is the component (A) and ( It may be the B) component, or the (A) component, the (B) component and the above additives.
The first resin composition may consist essentially of components (A) and (B), or components (A), (B) and the above additives. In this case, it may contain unavoidable impurities.
The first resin composition may consist of only components (A) and (B), or only components (A), (B) and the above additives.

[Second resin composition]
A resin composition (second resin composition) according to one aspect of the present invention contains the following components (A) to (C) in the following proportions.
(A) cellulose fiber dispersant 0.01 to 89.0% by mass
(B) Cellulose fiber 0.05 to 80.0% by mass
(C) thermoplastic resin 10.0 to 99.9% by mass

As described above, the cellulose fiber dispersant according to one aspect of the present invention can be used to uniformly disperse the cellulose fibers in the resin composition. Thereby, the molded article obtained from the second resin composition containing the above components has excellent mechanical properties (tensile yield strength, tensile modulus and elongation at break). Furthermore, by combining the component (A) and the component (B) having polar groups, it is possible to improve the adhesiveness and paintability of the surface of the molded product, as well as the adhesiveness and affinity with polar materials. It becomes possible. In addition, since the second resin composition has high kneadability, it can be easily prepared. target. Furthermore, since the components (A) and (B) can be prepared from naturally derived materials, they have a low environmental impact and are highly recyclable. In addition, by using the component (A), discoloration of the cellulose fibers can be suppressed, and environmental properties such as heat aging resistance and weather resistance can be improved.

The thermoplastic resin of component (C) is not particularly limited, but examples include polyolefin resins such as polypropylene, ethylene-propylene copolymer, high density polyethylene, low density polyethylene, linear low density polyethylene; Polyamide resins such as polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, polyamide 12, polyamide 11, aromatic polyamide; polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polybutylene succinate, polybutylene succinate adipate , polybutylene adipate terephthalate, polyethylene terephthalate succinate, poly(3-hydroxyalkanoic acid), poly(3-hydroxybutyric acid), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), polyglycolic acid, etc. styrene resins such as polystyrene, acrylonitrile-styrene resin and ABS resin; polycarbonate; polyacrylate; polymethyl methacrylate; polyacetal;

Among the above, polyolefin resins are preferred, and polypropylene and polyethylene are more preferred.
Polypropylene and polyethylene are not particularly limited, but from the viewpoint of obtaining a resin composition that is lightweight and excellent in moldability, the melt flow rate at 230 ° C. and a load of 2.16 kg is 0.1 to 200 g / 10 minutes. preferable. Furthermore, from the viewpoint of obtaining a molded article having excellent rigidity and impact resistance, it is more preferable that the melt flow rate at 230° C. and a load of 2.16 kg is 0.1 to 30 g/10 minutes.
Melt flow rate is measured by a method conforming to ASTM Standard D-1238.

The content of component (A) in the second resin composition is 0.01% by mass or more, preferably 0.02% by mass or more, for example, 0.1% by mass or more, or 0.5% by mass. Above, it is good also as 1.0 mass % or more, or 3.0 mass % or more.
The content of component (A) in the second resin composition is 89.0% by mass or less, preferably 70.0% by mass or less, more preferably 60.0% by mass or less, and still more preferably 50.0% by mass. % by mass or less, particularly preferably 40.0% by mass or less.

The content of component (B) in the second resin composition is 0.05% by mass or more, preferably 0.08% by mass or more, for example, 0.1% by mass or more, or 0.5% by mass. Above, it is good also as 1.0 mass % or more, or 3.0 mass % or more.
The content of component (B) in the second resin composition is 80.0% by mass or less, preferably 70.0% by mass or less, more preferably 60.0% by mass or less, and still more preferably 50.0% by mass. % by mass or less, particularly preferably 40.0% by mass or less.

The content of component (C) in the second resin composition is 10.0% by mass or more, preferably 15.0% by mass or more, more preferably 20.0% by mass or more, and still more preferably 25.0% by mass. It is at least 30.0% by mass, particularly preferably at least 30.0% by mass.
The content of component (C) in the second resin composition is 99.9% by mass or less, preferably 99.89% by mass or less, for example, 98.0% by mass or less, 95.0% by mass. Below, it is good also as 93.0 mass % or less, or 92.0 mass % or less.

The second resin composition can be blended with arbitrary additives according to various purposes (for example, improvement of workability, functionality and/or mechanical properties).
Additives include UV absorbers, antioxidants, light stabilizers, lubricants, crystal nucleating agents, softeners, antistatic agents, metal deactivators, antibacterial agents, foaming agents, modified resins, pigments, dyes, and reinforcing agents. , release agents, plasticizers, fluidity improvers and the like.
In addition, a flame retardant and a flame retardant auxiliary can be blended in order to assist flame retardancy. The flame retardant is not particularly limited, and may be phosphorus flame retardants, silicone flame retardants, halogen compounds, organic alkali metal salts, organic alkaline earth metal salts, nitrogen compounds, metal hydroxides, borate compounds, silicon compounds, Known materials such as metal oxides and expanded graphite can be used depending on the purpose. The flame retardant aid is not particularly limited, and antimony compounds such as antimony trioxide, zinc borate, metal oxides, melamine, pentaerythritol and the like can be used. Among these, antimony compounds are preferred.
The above additives may be used singly or in combination of two or more.

Any filler can be added to the second resin composition.
The filler is not particularly limited, and various known fillers can be used. Specifically, talc, calcium carbonate, silica, clay, potassium titanate, mica, glass fiber, glass balloon, wollastonite. , metal fiber, alumina, precipitated barium sulfate, calcium oxide, titanium oxide, zeolite, carbon fiber, carbon black, graphite, basic magnesium sulfate, and the like.
One of the above fillers may be used alone, or two or more thereof may be used in combination.

The second resin composition preferably contains 0.01% by mass or more of component (A), 0.05% by mass or more of component (B), and 20.0% by mass or more of component (C) (more preferably 30.0% by mass or more), preferably the component (A) is 50.0% by mass or less (more preferably 40.0% by mass or less), and the component (B) is 50.0% by mass or less (more preferably 40.0% by mass or less) and component (C) is 99.9% by mass or less.
When the content of each component is within the above range, the cellulose fibers are more uniformly dispersed in the resin composition, so that a molded article having excellent mechanical properties can be obtained.

For example, 70% by mass or more, 80% by mass or more, 90% by mass or more, 98% by mass or more, 99% by mass or more, or 99.9% by mass or more of the second resin composition is (A) component ~ ( It may be component C, or components (A) to (C) and the above additives and/or fillers.
The second resin composition may consist essentially of components (A) to (C), or components (A) to (C) and the above additives and/or fillers. In this case, it may contain unavoidable impurities.
The second resin composition may consist of only components (A) to (C), or may consist of only components (A) to (C) and the above additives and/or fillers.

[Method for producing the second resin composition]
The second resin composition can be produced by melt-kneading the above components, preferably, the step of kneading the water-containing component (B) and the component (A), and It is manufactured by a manufacturing method including a step of melt-kneading the mixture and component (C).

First, the water-containing component (B) and the component (A) are kneaded at 50° C. to 230° C. to replace the moisture between the cellulose fibers with the component (A). Aggregation of cellulose fibers during drying can be suppressed. The proportions of component (B) and water are as described above.

Next, the resin composition is obtained by melt-kneading the mixture obtained above and the component (C). By kneading the components (B) and (A) and then kneading the components (C), the cellulose fibers can be more uniformly dispersed in the thermoplastic resin.

Various processing machines can be used for melt-kneading. As a processing machine, a continuous extruder such as a twin-screw extruder and a 1.5-screw extruder; a batch kneader such as a kneader and a Banbury mixer; rolls, etc. can be used, preferably a continuous extruder.

[Molded body]
Since the second resin composition has excellent processability, a molded article (resin molded article) can be obtained by known methods such as extrusion molding, blow molding, injection molding, vacuum molding, and calender molding.

The field of application of the resulting molded product is not particularly limited, and examples include automobile parts such as bumpers, cowl tops, weather strips and other exterior parts, instrument panels, meter clusters, door trims, luggage boards, HVAC units and other interior parts. , engine parts such as air cleaner elements, etc., and home appliance parts such as freezer refrigerators, rice cookers, microwave ovens, washing machines, personal computers, air conditioners, outdoor units for air conditioners, hot water washing toilet seats, TV receivers, etc. Cases, various parts, etc. are listed, and in addition, OA equipment parts such as various parts such as housings and bearings for multifunction printers, speaker housings, speaker frames, acoustic parts such as diaphragms, and electrical equipment parts such as clamp covers. , building members such as bathroom counters and kitchen panels, and medical materials utilizing biocompatibility.

Reference example 1
[Production of cellulose fiber dispersant]
99 g of disproportionated rosin (“G-100F” manufactured by Harima Kasei Co., Ltd.) and 1 g of Chinese gum rosin are heated and dissolved at 200° C. under a nitrogen stream (5 ml/min), and 0.1 g of maleic anhydride is added and stirred. , it was confirmed that the Diels-Alder addition reaction was completed and the anhydride ring was opened by the disappearance of turbidity of the solution. After that, 10 g of glycerin was added, and the liquid temperature was raised to 270° C. over 8 to 10 hours. Thereafter, an esterification reaction was carried out at 270° C. for 16 to 20 hours to obtain maleic acid-modified disproportionated rosin glycerin ester A1 (cellulose fiber dispersant, acid modification rate 0.1% by mass).

Example 2
[Production of cellulose fiber dispersant]
100 g of Chinese gum rosin was dissolved by heating at 200°C under a nitrogen stream (5 ml/min), 2.8 g of fumaric acid was added, and the solution was stirred. to obtain fumaric acid-modified rosin A2 (cellulose fiber dispersant, acid modification rate: 2.8% by mass).

Reference example 2
[Production of cellulose fiber dispersant]
500 g of Chinese gum rosin was placed in a 1 L four-necked flask, 380 g of mineral spirit was added, and the mixture was heated and dissolved under a nitrogen stream (5 ml/min). When the mixture was completely melted and became stirrable, it was cooled to 130° C., 5 g of zinc chloride catalyst was added, and the mixture was reacted at the same temperature for 4 hours. After neutralization and washing with 0.5% sodium bicarbonate water three times or more, a crude polymerized rosin was obtained. The resulting crude polymerized rosin was distilled to remove decomposed products and contained solvent to obtain a polymerized rosin. Next, 100 g of polymerized rosin was heated and dissolved at 200° C. under a nitrogen stream (5 ml/min), 3.0 g of maleic anhydride was added and stirred, and the Diels-Alder addition reaction was completed when the turbidity of the solution disappeared. It was confirmed that the anhydride ring was opened. 10 g of pentaerythritol was added, and the liquid temperature was raised to 270° C. over 8 to 10 hours. Thereafter, an esterification reaction was carried out at 270° C. for 16 to 20 hours to obtain maleic acid-modified polymerized rosin pentaerythritol ester A3 (cellulose fiber dispersant, acid modification rate: 3.0 mass %).

Comparative example 1
[Production of rosin compound]
500 g of Chinese gum rosin was placed in a 1 L four-necked flask, 380 g of mineral spirit was added, and the mixture was heated and dissolved under a nitrogen stream (5 ml/min). When the mixture was completely melted and became stirrable, it was cooled to 130° C., 5 g of zinc chloride catalyst was added, and the mixture was reacted at the same temperature for 4 hours. After neutralization and washing with 0.5% sodium bicarbonate water three times or more, a crude polymerized rosin was obtained. The resulting crude polymerized rosin was distilled to remove decomposed products and contained solvent to obtain a polymerized rosin. Next, 100 g of polymerized rosin was heated and dissolved at 200° C. under a nitrogen stream (5 ml/min), 10 g of pentaerythritol was added, and the liquid temperature was raised to 270° C. over 8 to 10 hours. An esterification reaction was carried out at 270° C. for 16 to 20 hours to obtain polymerized rosin pentaerythritol ester A′1 (acid modification rate: 0 mass %).

Comparative example 2
[Production of rosin compound]
100 g of Chinese gum rosin was heated and dissolved at 200° C. under a nitrogen stream (5 ml/min), 5.8 g of maleic anhydride was added and stirred, and the Diels-Alder addition reaction was completed when the solution became clear of water. It was confirmed that the ring was opened. Thereafter, petroleum resin (“Quinton 1345” manufactured by Nippon Zeon Co., Ltd.) was charged, and the liquid temperature was raised to 270° C. over 8 to 10 hours. A polymerization reaction was carried out at 270° C. for 16 to 20 hours to obtain a petroleum resin-modified maleic acid-modified rosin A′2 (acid modification rate: 5.8 mass %).

Comparative example 3
[Production of rosin compound]
100 g of Chinese gum rosin was dissolved by heating at 200°C under a nitrogen stream (5 ml/min), 4.3 g of fumaric acid was added, and the solution was stirred. bottom. 15 g of glycerin was added, and the liquid temperature was raised to 270° C. over 8 hours. An esterification reaction was carried out at 270° C. for 15 to 20 hours to obtain a fumaric acid-modified rosin glycerin ester A′3 (acid modification rate: 4.3 mass %).

Examples 5-9 , Comparative Examples 4-8 , Experimental Example 1 and Reference Examples 3-4
[Production of resin composition and molding]
Among the components shown in Table 1, the component (A) or (A') and the component (B) (containing water, the water content is 78% by mass with respect to the total of the component (B) and water. ) were blended at the ratio shown in Table 1 and kneaded at 120 to 180° C. to obtain a resin composition (first resin composition). The water contained in the component (B) was discharged out of the system during kneading. Then, it was blended with the component (C) to prepare a resin composition (second resin composition). The numerical values in "resin composition" in Table 1 indicate the blending ratio (% by mass) of each component in the second resin composition. Further, 0.2 parts by mass of Irganox 1010 (manufactured by BASF) and 0.2 parts by mass of ADEKA STAB 2112 (manufactured by ADEKA Co., Ltd.) were blended as antioxidants with respect to 100 parts by mass of the obtained resin composition. .
The obtained resin composition was supplied to an extruder (“PCM-30” manufactured by Ikegai Co., Ltd.), melt-kneaded at 180 to 240° C., and pelletized. After drying the obtained pellets at 80 ° C., molding at 190 to 240 ° C. with an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd. "NEX110III-18E"), test pieces (molding, dimensions are ASTM for each evaluation described later. conforming to the standard) was obtained.

The components used are shown below.
((A) component: cellulose fiber dispersant)
They are A1 to A3 obtained in Examples 1 to 3.
· A1: maleic acid-modified disproportionated rosin glycerin ester (acid modification rate 0.1% by mass)
・A2: Fumaric acid-modified rosin (acid modification rate: 2.8% by mass)
・ A3: Maleic acid-modified polymerized rosin pentaerythritol ester (acid modification rate 3.0% by mass)
All of A1 to A3 are solid at 25°C.

((A') component: rosin compound)
These are A'1 to A'3 obtained in Comparative Examples 1 to 3.
· A'1: polymerized rosin pentaerythritol ester (acid modification rate 0% by mass)
・ A'2: Petroleum resin-modified maleic acid-modified rosin (acid modification rate 5.8% by mass)
・ A'3: Fumaric acid-modified rosin glycerin ester (acid modification rate 4.3% by mass)
All of A'1 to A'3 are solid at 25°C.

((B) component: cellulose fiber)
・B1: Cellulose fiber derived from vegetable pulp, average fiber diameter: 30 nm, average degree of polymerization: 600, α-cellulose content of vegetable pulp: 85% by mass
・B2: Cellulose fiber derived from vegetable pulp, average fiber diameter: 30 μm, average degree of polymerization: 2000, α-cellulose content of vegetable pulp: 85% by mass

((C) component: thermoplastic resin)
· C1: homopolypropylene, MFR: 0.5 g/10 minutes MFR is a value measured in accordance with ASTM D-1238 (2013) under conditions of 230°C and 2.16 kg/10 minutes.

[Evaluation of compact]
The following evaluations were carried out on the obtained compacts. Table 1 shows the results.
(1) Density Measured by a method conforming to ASTM D792 (2013) (unit: g/cm ³ ).
(2) Tensile yield strength Measured according to ASTM D638 (1986) (unit: MPa).
(3) Tensile modulus Measured according to ASTM D638 (1986) (unit: MPa).
(4) Elongation at break (between chucks)
Measured according to ASTM D638 (1986) (unit: %).
(5) Dispersed state (dispersibility)
The dispersion state of the material in the specimen was evaluated. Specifically, the test piece is immersed in liquid nitrogen for 1 minute and frozen, then bent and broken, and the cross section is observed at 2000 times using a scanning electron microscope (SEM). It was evaluated as "○", and when aggregates were observed, it was evaluated as "X". Comparative Examples 8 and 9, which did not contain cellulose, were given "-" because the dispersion state was not evaluated.

From Table 1, it can be seen that the resin composition according to one aspect of the present invention has high dispersibility of cellulose fibers, and the obtained molded article has excellent mechanical properties in a well-balanced manner.

Claims (12)

A dispersant for cellulose fibers used for dispersing cellulose fibers in a resin composition containing a polyolefin resin,
A dispersant for cellulose fibers, comprising a fumaric acid-modified rosin having an acid modification rate of 0.08 to 4.0% by mass. A first resin composition containing the following components (A) and (B) in the following proportions based on the total amount of the following components (A) and (B) .
(A) 0.1 to 99.9% by mass of the dispersant for cellulose fibers according to claim 1
(B) 0.1 to 99.9% by mass of cellulose fibers having a moisture content of 50% by mass or more and 99.0% by mass or less with respect to the total of cellulose fibers and moisture 3. The resin composition according to claim 2 , wherein the cellulose fibers of component (B) have an average fiber diameter of 3 nm to 50 μm. 4. The resin composition according to claim 2 , wherein the component (B) is a plant-derived cellulose fiber. A second resin composition containing the following components (A) to (C) in the following proportions based on the total amount of the following components (A) to (C) .
(A) 0.01 to 89.0% by mass of the dispersant for cellulose fibers according to claim 1
(B) Cellulose fiber 0.05 to 80.0% by mass
(C) Polyolefin resin 10.0 to 99.9% by mass 6. The resin composition according to claim 5 , wherein the average fiber diameter of the cellulose fibers of component (B) is 3 nm to 50 μm. 7. The resin composition according to claim 5 , wherein the component (B) is a plant-derived cellulose fiber. The resin composition according to any one of claims 5 to 7 , wherein the component (C) is polypropylene. The resin composition according to any one of claims 5 to 8 , wherein the component (C) has a melt flow rate of 0.1 to 200 g/10 minutes at 230°C and a load of 2.16 kg. Based on the total amount of the components (A) to (C), the content of the component (A) is 0.01 to 50.0% by mass, and the content of the component (B) is 0.05 to 50.0% by mass. 10. The resin composition according to any one of claims 5 to 9 , wherein the content of component (C) is 50.0% by mass and the content of component (C) is 20.0 to 99.9% by mass. a step of kneading cellulose fibers containing water and the dispersant for cellulose fibers according to claim 1 ;
A method for producing a resin composition, comprising the step of melt-kneading the mixture obtained in the above step and a thermoplastic resin. A molded article produced using the resin composition according to any one of claims 5 to 11 .