JP7757839B2 - Flowability improver for resin composition, molded article and polyolefin resin - Google Patents

Description

The present invention relates to a resin composition, a molded article, and a flowability improver for polyolefin resins.

Polyolefin resins have excellent mechanical properties and are used in a variety of applications, including injection-molded products, blow-molded products, films, sheets, and fibers.

These polyolefin resins have excellent impact strength, but have poor fluidity when melted, causing problems such as melt fracture when molded at high speeds. For this reason, additives such as lubricants are typically added to the polyolefin resin to reduce the apparent flow viscosity when melted, improving moldability and increasing the extrusion rate, thereby improving productivity (Patent Document 1).

However, when conventional lubricants are used, while increasing the amount of lubricant improves melt fluidity, there is a problem in that the mechanical strength of the polyolefin resin decreases.

JP 2012-009754 A

The present invention was made in consideration of the above circumstances, and aims to provide a polyolefin resin composition that has excellent moldability while maintaining the mechanical strength of polyolefin resins.

Another objective of the present invention is to provide a novel flow improver that can improve the molding processability of polyolefin resins while maintaining the mechanical strength of the polyolefin resins.

After extensive research, the present inventors have discovered that the above-mentioned problems can be solved by a composition in which a specific rosin acid is used in a specified amount in a polyolefin resin. The present inventors have also discovered that the above-mentioned problems can be solved by a flow improver containing a specific rosin acid. Specifically, the present invention relates to the following resin composition, molded article, and flow improver.

1. A composition comprising a polyolefin resin (A) and a rosin acid (B),
the rosin acid (B) has a weight average molecular weight of 280 to 340;
The resin composition has a content of the rosin acid (B) of 0.1 to 5 parts by mass per 100 parts by mass of the polyolefin resin (A).

2. The resin composition described in item 1 above, wherein component (A) is at least one selected from the group consisting of polyethylene and polypropylene.

3. The resin composition according to item 1 or 2, wherein the acid value of component (B) is 130 to 200 mgKOH/g.

4. The resin composition according to any one of items 1 to 3, wherein component (B) is at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin.

5. A molded article obtained from the resin composition described in any one of items 1 to 4 above.

6. A flowability improver for polyolefin resins, comprising a rosin acid (B) having a weight-average molecular weight of 280 to 340.

7. The flowability improver for polyolefin resins according to item 6 above, wherein the polyolefin resin is at least one selected from the group consisting of polyethylene and polypropylene.

8. The flowability improver for polyolefin resins according to item 6 or 7, wherein the acid value of component (B) is 130 to 200 mgKOH/g.

9. The flowability improver for polyolefin resins according to any one of items 6 to 9, wherein component (B) is at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin.

The resin composition of the present invention has excellent fluidity when melted while maintaining the mechanical strength of polyolefin resins, resulting in excellent moldability. Furthermore, when used in polyolefin resins, the flowability improver of the present invention improves the fluidity of polyolefin resins when melted while maintaining their mechanical strength, thereby improving their moldability.

[Resin composition]
The resin composition of the present invention contains a polyolefin resin (A) (hereinafter also referred to as component (A)) and a rosin acid (B) (hereinafter also referred to as component (B)).

<Polyolefin resin (A)>
The component (A) is not particularly limited, and various known components can be used. The component (A) may be used alone or in combination of two or more.

Component (A) can be, for example, a homopolymer of an α-olefin having approximately 2 to 8 carbon atoms, such as ethylene, propylene, or 1-butene; or a binary or ternary (co)polymer of such an α-olefin with another α-olefin having approximately 2 to 18 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, or 1-octadecene, or vinyl acetate.

Examples of component (A) include ethylene-based resins such as polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, and ethylene-1-octene copolymer; propylene-based resins such as polypropylene, propylene-ethylene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-4-methyl-1-pentene copolymer, and propylene-ethylene-1-hexene copolymer; 1-butene-based resins such as 1-butene homopolymer, 1-butene-ethylene copolymer, and 1-butene-propylene copolymer; and 4-methyl-1-pentene-based resins such as 4-methyl-1-pentene homopolymer and 4-methyl-1-pentene-ethylene copolymer.

In terms of excellent moldability, component (A) is preferably a homopolymer of an α-olefin having approximately 2 to 8 carbon atoms, such as ethylene, propylene, or 1-butene; or a binary or ternary (co)polymer of the above α-olefin with another α-olefin having approximately 2 to 18 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, or 1-octadecene. For the same reasons, at least one selected from the group consisting of polyethylene and polypropylene is more preferred.

Note that component (A) is not preferred if it is a copolymer of the above-mentioned α-olefin and unsaturated carboxylic acid, or a salt of such a copolymer, as this reduces moldability. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride.

<Rosin acid (B)>
The component (B) is not particularly limited, and various known rosin acids can be used as long as they are rosin acids having a weight average molecular weight (Mw) of 280 to 340. The component (B) may be used alone or in combination of two or more.

By using component (B), the resin composition of the present invention has improved fluidity when melted, resulting in excellent moldability, while maintaining the mechanical strength of component (A). When using a rosin-based resin other than component (B), such as rosin esters, which are reaction products of rosin acid and alcohol, or various metal salts of rosin acid, the resin composition does not have improved or reduced fluidity when melted, resulting in poor moldability.

Examples of component (B) include natural rosins (gum rosin, tall oil rosin, wood rosin) derived from Pinus massoniana, Slash pine (Pinus elliottii), Merkusii, Caribbean pine (Pinus caribaea), Pinus kesiya, Loblolly pine (Pinus taeda), and Great King pine (Pinus palustris), purified rosin (hereinafter, natural rosin and purified rosin are collectively referred to as unmodified rosin), hydrogenated rosin, and disproportionated rosin .

The purified rosin can be obtained using various known methods. Specifically, it can be obtained using various known purification methods, such as distillation, extraction, recrystallization, and adsorption. Examples of distillation methods include distilling the natural rosin at a temperature of approximately 200-300°C under a reduced pressure of approximately 0.01-3 kPa. Examples of extraction methods include dissolving the natural rosin in an alkaline aqueous solution, extracting the insoluble unsaponifiable matter with various organic solvents, and then neutralizing the aqueous layer. Examples of recrystallization methods include dissolving the natural rosin in an organic solvent as a good solvent, distilling off the solvent to obtain a concentrated solution, and then adding an organic solvent as a poor solvent. Examples of good solvents include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, chlorinated hydrocarbon solvents such as chloroform, lower alcohols, ketones such as acetone, and acetate esters such as ethyl acetate. Examples of poor solvents include n-hexane, n-heptane, cyclohexane, and isooctane. Examples of adsorption methods include contacting the natural rosin in a molten state or in solution in an organic solvent with a porous adsorbent. Examples of porous adsorbents include activated carbon, metal oxides such as alumina, zirconia, silica, molecular sieves, zeolites, and microporous clay.

Furthermore, the purified rosin obtained may be subjected to the disproportionation and hydrogenation procedures described below, either alone or in combination of two or more thereof.

The disproportionated rosin can be obtained using various known methods. Specifically, for example, it can be obtained by heating the unmodified rosin in the presence of a disproportionation catalyst (disproportionation). Examples of known disproportionation catalysts that can be used include supported catalysts such as palladium-carbon, rhodium-carbon, and platinum-carbon; metal powders such as nickel and platinum; and iodides such as iodine and iron iodide. The amount of catalyst used is typically about 0.01 to 5 parts by mass, and preferably about 0.01 to 1 part by mass, per 100 parts by mass of unmodified rosin. The reaction temperature is about 100 to 300°C, and preferably about 150 to 290°C.

Furthermore, the disproportionated rosin obtained may be further subjected to the above-mentioned purification, disproportionation, and hydrogenation procedures described below, either alone or in combination of two or more thereof.

The hydrogenated rosin can be obtained using various known methods. Specifically, for example, it can be obtained by hydrogenating the unmodified rosin using known hydrogenation conditions. Examples of hydrogenation conditions include heating the unmodified rosin to approximately 100 to 300°C at a hydrogen pressure of approximately 2 to 20 MPa in the presence of a hydrogenation catalyst. Preferably, the hydrogen pressure is approximately 5 to 20 MPa and the reaction temperature is approximately 150 to 300°C. Various known hydrogenation catalysts can be used, including supported catalysts and metal powders. Supported catalysts include palladium-carbon, rhodium-carbon, ruthenium-carbon, and platinum-carbon. Metal powders include nickel and platinum. Among these, palladium, rhodium, ruthenium, and platinum-based catalysts are preferred because they increase the hydrogenation rate of the unmodified rosin and shorten the hydrogenation time. The amount of hydrogenation catalyst used is typically about 0.01 to 5 parts by mass, and preferably about 0.01 to 2 parts by mass, per 100 parts by mass of the unmodified rosin.

If necessary, the hydrogenation may be carried out with the unmodified rosin dissolved in a solvent. There are no particular restrictions on the solvent used, as long as it is inert to the reaction and easily dissolves the raw materials and products. Specifically, for example, cyclohexane, n-hexane, n-heptane, decalin, tetrahydrofuran, dioxane, etc. can be used alone or in combination with two or more. There are no particular restrictions on the amount of solvent used, but it is usually sufficient to use it so that the solids content is 10% by mass or more, preferably in the range of approximately 10 to 70% by mass, relative to the unmodified rosin.

Furthermore, the hydrogenated rosin obtained may be further subjected to the above-mentioned purification, hydrogenation, and disproportionation procedures, either alone or in combination of two or more thereof.

Furthermore, to improve the color tone of component (B), purified rosin, hydrogenated rosin, and disproportionated rosin may be further subjected to a dehydrogenation treatment. The dehydrogenation treatment is not particularly limited, and conventional conditions can be used. For example, component (B) is dehydrogenated in a sealed container in the presence of a dehydrogenation catalyst at an initial hydrogen pressure of less than 10 kg/cm2, preferably less than 5 kg/cm2, and at a reaction temperature of approximately 100 to 300°C, with a lower limit of 200°C and an upper limit of 280°C. There are no particular restrictions on the dehydrogenation catalyst, and various known catalysts can be used. Preferred examples include palladium-, rhodium-, and platinum-based catalysts, which are typically supported on a carrier such as silica or carbon. The amount of catalyst used is typically approximately 0.01 to 5% by weight of component (B), with a lower limit of 0.05% by weight and an upper limit of 3% by weight.

Component (B) is preferably at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin, as this will result in excellent mechanical strength and moldability of the resin composition.

(Physical Properties of Rosin Acid (B))
The weight average molecular weight (Mw) of component (B) is 280 to 340. In this specification, the weight average molecular weight (Mw) is a polystyrene-equivalent value determined by gel permeation chromatography (GPC).

When the weight-average molecular weight of component (B) is 280 or more, the resin composition has excellent mechanical strength. When the weight-average molecular weight of component (B) is 340 or less, the resin composition has excellent mechanical strength and moldability. The weight-average molecular weight of component (B) is preferably approximately 300 to 320, as this will result in excellent mechanical strength and moldability of the resin composition.

If the weight-average molecular weight of component (B) exceeds 340, the moldability and mechanical strength of the resin composition will decrease. Examples of such rosin acids include rosins modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride (unsaturated carboxylic acid-modified rosins), polymerized rosins, etc.

Component (B) is not particularly limited in terms of its physical properties other than its weight-average molecular weight. The acid value of component (B) is preferably approximately 130 to 200 mgKOH/g in order to provide excellent mechanical strength and moldability to the resin composition, and more preferably approximately 150 to 195 mgKOH/g in terms of the same. In the present invention, the acid value is a value measured in accordance with JIS K0070 or a value measured by the method described in the Examples below.

The color tone of component (B) is preferably 8 Gardner or less, more preferably 10 to 400 Hazen, and particularly preferably 10 to 200 Hazen, in order to suppress discoloration in the resin composition. In this specification, color tone is measured in accordance with JIS K 0071-1 for Hazen units and JIS K 0071-2 for Gardner units.

Component (B) may contain various known additives as needed, as long as the effects of the present invention are not impaired. Examples of additives include dehydrating agents, weathering agents, antioxidants, UV absorbers, heat stabilizers, and light stabilizers. The above additives can be used alone or in combination of two or more.

(Additives)
The resin composition may contain additives as needed, as long as they do not impair the effects of the present invention. Examples of additives include flame retardants (e.g., phosphorus-containing epoxy resins, red phosphorus, phosphazene compounds, phosphates, phosphate esters, etc.), silicone oil, wetting and dispersing agents, antifoaming agents, defoamers, natural waxes, synthetic waxes, metal salts of straight-chain fatty acids, fatty acid amides, esters, paraffins, and other mold release agents, crystalline silica, fused silica, calcium silicate, alumina, calcium carbonate, talc, inorganic pigments, organic pigments, dehydrating agents, crystal nucleating agents, plasticizers, flow improvers other than component (B), weathering agents, antioxidants, ultraviolet absorbers, heat stabilizers, and light stabilizers.

Examples of the inorganic pigments include cadmium red, cadmium lemon yellow, cadmium yellow orange, titanium dioxide, carbon black, black iron oxide, and black complex inorganic pigments.

Examples of the organic pigments include aniline black, perylene black, anthraquinone black, benzidine-based yellow pigments, phthalocyanine blue, and phthalocyanine green.

(Content of each ingredient)
The content of the component (B) in the resin composition is 0.1 to 5 parts by mass per 100 parts by mass of the component (A).

When the content of component (B) is 0.1 parts by mass or more per 100 parts by mass of component (A), the resin composition has excellent moldability. When the content of component (B) is 5 parts by mass or less per 100 parts by mass of component (A), the resin composition has excellent moldability and maintains its mechanical strength.

The content of component (B) in the above resin composition is preferably 0.3 to 2 parts by mass per 100 parts by mass of component (A), as this provides excellent mechanical strength and moldability of the resin composition.

The content of the additives in the resin composition is not particularly limited, but is typically 0.001 parts by mass or more, preferably 0.005 parts by mass or more, and more preferably 0.01 parts by mass or more, per 100 parts by mass of the resin composition, and is typically 100 parts by mass or less, and preferably 50 parts by mass or less.

(Method for producing resin composition)
The method for producing the resin composition is not particularly limited, and various known methods can be used. Examples of methods for producing the resin composition include premixing component (A), component (B), and, if necessary, the additives using a mixer such as a tumbler mixer or a Henschel mixer, followed by melt-kneading using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, or a kneader. The temperature for the melt-kneading is not particularly limited, but is typically in the range of 170 to 300°C, preferably 180 to 250°C.

[Molded body]
The molded article of the present invention can be obtained by molding the resin composition by any of various known molding methods. The shape of the molded article is not particularly limited and can be appropriately selected depending on the use and purpose of the molded article, and examples thereof include plate-like, plate-like, rod-like, sheet-like, film-like, cylindrical, ring-like, circular, elliptical, polygonal, irregular-shaped, hollow, frame-like, box-like, and panel-like shapes.

The method for molding the molded article is not particularly limited, and any conventionally known molding method can be used. Specific examples include injection molding, injection compression molding, extrusion molding, stretch film molding, inflation molding, profile extrusion, transfer molding, blow molding, gas-assisted blow molding, blow molding, extrusion blow molding, in-mold coating (IMC) molding, press molding, rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, and pressure molding. Among these, injection molding is preferred. Examples of injection molding machines include well-known injection molding machines such as ultra-high-speed injection molding machines and injection compression molding machines.

The above-mentioned molded articles are suitable for a wide range of applications, from household goods to industrial products, such as automotive interior materials, automotive materials such as exterior panels and bumpers, electrical and electronic equipment, home appliance parts, office automation equipment, information terminal equipment, machine parts, packaging materials, construction materials, civil engineering materials, fishery materials, various containers, lighting equipment, films, sheets, fibers, and other industrial materials.

Examples of the above-mentioned electrical and electronic devices include display devices such as car navigation systems, personal computers, game consoles, televisions, and electronic paper, as well as display devices such as printers, copiers, fax machines, electronic organizers and PDAs, electronic desk calculators, electronic dictionaries, cameras, video cameras, and DVD players, as well as mobile phones, tablet-type mobile devices, and touch-screen mobile devices.

[Flow improver]
The flowability improver of the present invention contains the above-mentioned component (B). When used in a polyolefin resin, the flowability improver of the present invention improves the flowability of the polyolefin resin when melted while maintaining the mechanical strength of the polyolefin resin, thereby improving its molding processability. If the flowability improver contains a rosin-based resin other than component (B), such as a rosin ester, which is a reaction product of rosin acid and alcohol, or various metal salts of rosin acid, the flowability of the polyolefin resin when melted cannot be improved or is reduced, making it impossible to improve its molding processability. Note that the flowability improver of the present invention is different from the above-mentioned resin composition.

The above-mentioned flow improver can be used with various known polyolefin resins. Examples of such polyolefin resins include the above-mentioned component (A). The polyolefin resins may be used alone or in combination of two or more.

The polyolefin resins for which the flow improver is used are preferably homopolymers of α-olefins having approximately 2 to 8 carbon atoms, such as ethylene, propylene, and 1-butene, due to their excellent moldability; or binary or ternary (co)polymers of the above α-olefins with other α-olefins having approximately 2 to 18 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, and 1-octadecene. For the same reasons, at least one selected from the group consisting of polyethylene and polypropylene is more preferred.

The (B) component in the above-mentioned flow improver is preferably at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin, as this will provide excellent mechanical strength and molding processability to the polyolefin resin.

The weight-average molecular weight (Mw) of component (B) in the above-mentioned flow improver is 280 to 340. Note that in this specification, the weight-average molecular weight (Mw) is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

When the weight-average molecular weight of component (B) is 280 or more, the mechanical strength of the polyolefin resin is maintained. When the weight-average molecular weight of component (B) is 340 or less, the mechanical strength of the polyolefin resin is maintained while its molding processability is improved. The weight-average molecular weight of component (B) is preferably approximately 300 to 320, as this will result in excellent mechanical strength and molding processability of the polyolefin resin.

If the weight-average molecular weight of component (B) exceeds 340, the molding processability and mechanical strength of the polyolefin resin will decrease. Examples of such rosin acids include rosins modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride (unsaturated carboxylic acid-modified rosins), polymerized rosins, etc.

The physical properties of component (B) in the above-mentioned flow improver are not particularly limited except for the weight-average molecular weight. The acid value of component (B) is preferably approximately 130 to 200 mgKOH/g in order to provide excellent mechanical strength and moldability to the polyolefin resin, and more preferably approximately 150 to 195 mgKOH/g in order to provide excellent mechanical strength and moldability to the polyolefin resin. In the present invention, the acid value is a value measured in accordance with JIS K0070 or a value measured by the method described in the Examples below.

The color tone of component (B) in the flowability improver is preferably 8 Gardner or less, more preferably 10 to 400 Hazen, and particularly preferably 10 to 200 Hazen, in order to suppress discoloration of the polyolefin resin. In this specification, color tone is measured in accordance with JIS K 0071-1 for Hazen units and JIS K 0071-2 for Gardner units.

The amount of the flow improver used is not particularly limited, but it is preferably 0.1 to 5 parts by mass per 100 parts by mass of polyolefin resin.

When the amount of the flow improver used is 0.1 parts by mass or more per 100 parts by mass of polyolefin resin, the molding processability of the polyolefin resin is superior. When the amount of the flow improver used is 5 parts by mass or less per 100 parts by mass of polyolefin resin, the molding processability of the polyolefin resin is superior and its mechanical strength is maintained.

The amount of the flow improver used is preferably 0.3 to 2 parts by mass per 100 parts by mass of polyolefin resin, as this provides excellent mechanical strength and moldability of the polyolefin resin.

The flow improver of the present invention may contain various known additives as needed, as long as the effects of the present invention are not impaired. Examples of additives include dehydrating agents, weathering agents, antioxidants, UV absorbers, heat stabilizers, and light stabilizers. The above additives can be used alone or in combination of two or more. The content of the above additives is not particularly limited, but is preferably 0.5 to 10 parts by mass per 100 parts by mass of the flow improver.

The method of using the flowability improver of the present invention is not particularly limited. For example, the flowability improver may be added to a mixer together with a polyolefin resin, and the mixture is melt-kneaded using the mixer. Examples of the mixer include a Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, and kneader.

The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples. In the examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively.

(Production of Rosin Acid (B))
Production Example 1
A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 1,000 parts of gum rosin (acid value 172 mg KOH/g, softening point 75°C) and 0.3 parts of 5% palladium carbon (water content 50%) as a disproportionation catalyst, and the mixture was stirred at 280°C for 4 hours under a nitrogen blanket to carry out a disproportionation reaction, thereby obtaining a disproportionated rosin (hereinafter referred to as component (B1)) having an acid value of 160 mg KOH/g, a weight-average molecular weight of 320, and a color tone of 6 (Gardner).

Production Example 2
A 3-liter autoclave was charged with 1,000 parts of gum rosin (acid value 171 mg KOH/g, softening point 76°C, color Gardner 6) and 2 parts of 5% palladium carbon (water content 50%) as a hydrogenation catalyst. After removing oxygen from the system, the system was pressurized to 100 kg/ ^cm2 with hydrogen and then heated to 260°C with stirring. Hydrogenation reaction was carried out at the same temperature for 3 hours to obtain hydrogenated rosin. Next, the hydrogenated rosin was distilled under a nitrogen blanket at a reduced pressure of 3 mmHg to obtain purified hydrogenated rosin. Then, 200 parts of the purified hydrogenated rosin and 0.1 part of 5% palladium carbon (water content: 50%) were charged into a 1-liter shaking autoclave, and the system was purged with nitrogen to remove oxygen. The system was then heated to 250°C and a dehydrogenation reaction was carried out at that temperature for 3 hours, yielding a hydrogenated rosin (hereinafter referred to as component (B2)) having an acid value of 172.6 mgKOH/g, a weight-average molecular weight of 300, and a color tone of 80 Hazen.

(Acid value)
The acid values of components (B1) to (B2) and components (b1) to (b3) were measured in accordance with JIS K 0070. The results are shown in Tables 1 and 2.

The acid value of component (b4) was measured using the following method. The results are shown in Tables 1 and 2.

A solution was prepared by dissolving 0.3 g of component (b4) in 50 ml of acetone and adding 25 ml of 0.1 mol/L aqueous potassium hydroxide solution to the solution. The solution was then left to stand for 10 minutes, and after adding a few drops of phenolphthalein as an indicator, titration was carried out with 0.1 mol/L hydrochloric acid. The acid value of component (b4) was calculated from the titrated amount of hydrochloric acid and the weight of component (b4) using the following formula:

Acid value (mg KOH/g) = {25 - titration amount of hydrochloric acid (ml)} × 5.611 / (b4) Weight (g) of component

(color tone)
The color tones of components (B1) and (B2) were measured in Hazen units according to JIS K 0071-1 and in Gardner units according to JIS K 0071-2.

(Measurement of weight average molecular weight (Mw))
The weight average molecular weights (Mw) of components (B1) to (B2) and components (b1) to (b4) were calculated as polystyrene equivalent values using gel permeation chromatography (GPC) based on a calibration curve of standard polystyrene. The GPC measurements were performed under the following conditions. The results are shown in Tables 1 and 2.
Analytical device: HLC-8320 (manufactured by Tosoh Corporation)
Column: Three types of columns connected: TSK guard column HXL-L, TSK-GEL G2000HXL, and TSK-GEL G1000HXL. Eluent: tetrahydrofuran. Injected sample concentration: 3 mg/mL.
Sample flow rate: 1.0 mL/min
Reference flow rate: 0.5 mL/min
Injection volume: 40μL
Column temperature: 40°C
Detector: RI, UV (254 nm)

[Preparation of Resin Composition]
Example 1
100 parts of polypropylene (manufactured by Japan Polypropylene Corporation, product name "Novatec PP MA3") (hereinafter referred to as PP) and 1 part of component (B1) were placed into a roller mixer-type kneading device (manufactured by Toyo Seiki Seisakusho, product name "Labo Plastomill Model 10C100") and kneaded for 5 minutes at a roller rotation speed of 40 rpm and a temperature of 190° C. The resulting kneaded product was then removed from the kneading device, hot-pressed at 200° C. to form a 1.0 mm thick sheet, and cut into 5 mm x 5 mm pieces using a cutter to obtain pellets (resin composition).

Example 2
A resin composition was obtained in the same manner as in Example 1, except that 1 part of the component (B2) was used instead of the component (B1).

Example 3
A resin composition was obtained in the same manner as in Example 1, except that 0.3 parts of the component (B1) was used.

Comparative Example 1
100 parts of PP were placed in a roller mixer-type kneading device (manufactured by Toyo Seiki Seisakusho, Ltd., product name "Labo Plastomill Model 10C100") and kneaded for 5 minutes at a roller rotation speed of 40 rpm and a temperature of 190° C. Thereafter, the resulting kneaded product was removed from the kneading device, hot-pressed at 200° C., and molded into a sheet with a thickness of 1.0 mm, which was then cut into 5 mm x 5 mm pieces using a cutter to obtain pellets (resin composition).

Comparative Example 2
Pellets (resin composition) were obtained in the same manner as in Example 1, except that in Example 1, component (B1) was replaced with one part of hydrogenated rosin ester (manufactured by Arakawa Chemical Industries, Ltd., product name "KE-311", weight average molecular weight 780, acid value 6 mgKOH/g) (hereinafter referred to as component (b1)).

Comparative Example 3
Pellets (resin composition) were obtained in the same manner as in Example 1, except that in Example 1, component (B1) was replaced with one part of a hydrogenated acrylic acid-modified rosin (manufactured by Arakawa Chemical Industries, Ltd., product name "KE-604", weight average molecular weight 380, acid value 240 mgKOH/g) (hereinafter referred to as component (b2)).

Comparative Example 4
Preparation was carried out in the same manner as in Example 1, except that in Example 1, part of polymerized rosin (manufactured by Arakawa Chemical Industries, Ltd., product name "R-140", weight average molecular weight 520, acid value 145 mgKOH/g) (hereinafter referred to as component (b3)) was used instead of component (B1), to obtain pellets (resin composition).

Comparative Example 5
Pellets (resin composition) were obtained in the same manner as in Example 1, except that 0.3 parts of maleic acid-modified rosin ester (manufactured by Arakawa Chemical Industries, Ltd., trade name "Marquid No. 32", weight average molecular weight 1,740, acid value 180 mgKOH/g) (hereinafter referred to as "component (b4)") was used instead of component (B1).

Example 4
100 parts of polyethylene (manufactured by Rhombic Corporation, product name "LLDPE RLL1BF") (hereinafter referred to as PE) and 1 part of component (B1) were placed into a roller mixer-type kneading device (manufactured by Toyo Seiki Seisaku-sho, product name "Labo Plastomill Model 10C100") and kneaded for 5 minutes at a roller rotation speed of 40 rpm and a temperature of 210° C. The resulting resin (composition) was then removed from the kneading device, hot-pressed at 180° C. to form a 1.0 mm thick sheet, and cut into 5 mm x 5 mm pieces using a cutter to obtain pellets.

Example 5
A resin composition was obtained in the same manner as in Example 4, except that 1 part of the component (B2) was used instead of the component (B1).

Example 6
A resin composition was obtained in the same manner as in Example 4, except that 0.3 parts of the component (B1) was used.

Comparative Example 6
100 parts of PE were placed in a roller mixer-type kneading device (manufactured by Toyo Seiki Seisakusho, Ltd., product name "Labo Plastomill Model 10C100") and kneaded for 5 minutes at a roller rotation speed of 40 rpm and a temperature of 210° C. Thereafter, the resulting kneaded product was removed from the kneading device, hot-pressed at 180° C., and molded into a sheet with a thickness of 1.0 mm, which was then cut into 5 mm × 5 mm pieces using a cutter to obtain pellets (resin composition).

Comparative Example 7
Pellets (resin composition) were obtained in the same manner as in Example 4, except that 1 part of component (b1) was used instead of component (B1).

Comparative Example 8
Pellets (resin composition) were obtained in the same manner as in Example 4, except that 1 part of component (b2) was used instead of component (B1).

Comparative Example 9
Pellets (resin composition) were obtained in the same manner as in Example 4, except that 0.3 parts of component (b4) was used instead of component (B1).

(Evaluation of molding processability)
In accordance with JIS K 7210, the MFR of each pellet was measured under conditions of a temperature of 230°C and a load of 21.2 N (2.16 kg) for the pellets of Examples 1 to 3 and Comparative Examples 1 to 5, and a temperature of 190°C and a load of 21.2 N (2.16 kg) for the pellets of Examples 4 to 6 and Comparative Examples 6 to 9. The results are shown in Tables 1 and 2.

(Evaluation of mechanical strength)
The pellets (resin compositions) obtained above were placed in a 100 mm x 100 mm x 1.0 mm mold and press-molded at 200°C for the pellets of Examples 1 to 3 and Comparative Examples 1 to 5, and at 180°C for the pellets of Examples 4 to 6 and Comparative Examples 6 to 9, to obtain 1.0 mm thick resin sheets (molded articles). The resulting resin sheets were punched using a punching blade conforming to JIS K7139-A23 to obtain dumbbell test pieces for measuring mechanical strength. These test pieces were subjected to a tensile test using a Shimadzu Corporation "Universal Testing Machine AGX-V" to measure the nominal strain at break (%). The results are shown in Tables 1 and 2.

The blending amounts in Tables 1 and 2 are values in parts by mass. The abbreviations in Tables 1 and 2 are as follows.
(Compound abbreviations and details)
PP: Polypropylene, product name "Novatec PP MA3", manufactured by Japan Polypropylene Corporation PE: Polyethylene, product name "LLDPE RLL1BF", manufactured by Rhombic Co., Ltd.

Claims (7)

A composition comprising a polyolefin resin (A) and a rosin acid (B),
the rosin acid (B) has a weight average molecular weight of 280 to 340;
the content of the rosin acid (B) is 1 to 5 parts by mass relative to 100 parts by mass of the polyolefin resin (A) ,
The polyolefin resin (A) is at least one selected from the group consisting of polyethylene and polypropylene.
Resin composition. The resin composition according to claim 1 , wherein the acid value of component (B) is 130 to 200 mg KOH/g. 3. The resin composition according to claim 1, wherein the component (B) is at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin. A molded article obtained from the resin composition according to any one of claims 1 to 3 . A flowability improver for polyolefin resins, comprising a rosin acid (B) having a weight-average molecular weight of 280 to 340,
The polyolefin resin is at least one selected from the group consisting of polyethylene and polypropylene.
Flow improver. 6. The flowability improver for polyolefin resins according to claim 5 , wherein the acid value of component (B) is 130 to 200 mg KOH/g. 7. The flowability improver for polyolefin resins according to claim 5 , wherein component (B) is at least one selected from the group consisting of natural rosin, purified rosin, hydrogenated rosin, and disproportionated rosin.