Resin particles and their applications

Abstract

To provide resin particles which can impart slidability and are excellent in long-term lasting property of the slidability, and application of the same.MEANS FOR SOLVING THE PROBLEM: Resin particles contain a lubricant and a thermoplastic resin, in which an extraction rate by n-hexane is 0-30%. Preferably, the thermoplastic resin is a polymer of a polymerizable component including at least one monomer selected from a monomer (A) and a monomer (B), the monomer (A) is a monomer having one polymerizable carbon-carbon double bond, and the monomer (B) is a monomer having at least two polymerizable carbon-carbon double bonds.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to resin particles and their applications. [Background technology]

[0002] Rubber and resins are used in a wide variety of fields and applications as components in automobiles, building materials, home appliances, office automation equipment, and more. Depending on the component, low frictional resistance and excellent sliding properties are required. Methods for imparting sliding properties include directly applying a lubricant to the component, adhering a lubricating film to the component, and creating a component by molding a mixture of a substrate and a lubricant. For example, one method involves applying urethane-based paint or silicone-based paint to a substrate such as a thermoplastic resin to form a lubricating film. However, this method has drawbacks, such as the resulting lubricating film being harder than the substrate, restrictions on the use of organic solvents, and the labor-intensive nature of the process. Patent Document 1 exemplifies a resin composition for forming a lubricating film with excellent sliding durability, which contains microcapsules made of thermosetting resin encapsulating a liquid lubricant. However, the method described in Patent Document 1 does not solve the above problem, and furthermore, there is a problem that the sliding properties cannot be maintained for a long period of time. In addition, sliding members obtained by adding a lubricant such as silicone oil to a thermoplastic resin and molding it have been proposed, but the lubricant tends to bleed out onto the surface of the member, the appearance deteriorates over time, and repeated friction removes the lubricant, reducing the sliding properties.

[0003] Patent Document 2 provides an example of an abrasion-resistant thermoplastic resin composition characterized by the inclusion of silicone oil and / or silicone polymer and silicone powder in a thermoplastic resin. By including silicone powder, the silicone oil is absorbed by the silicone powder, suppressing bleed-out. Furthermore, Patent Document 3 provides an example of a sliding material in which PE particles are kneaded into the base materials PP and EPDM. The PE particles create an uneven surface on the sliding material, reducing the contact area, thereby decreasing the coefficient of friction and wear, and improving sliding performance. However, even in Patent Documents 2 and 3, sufficient sliding properties could not be obtained, or the sliding properties could not be maintained for a long period of time. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-73609 [Patent Document 2] Japanese Patent Publication No. 2000-109702 [Patent Document 3] International Publication No. 2016 / 052029 Brochure [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, the object of the present invention is to provide resin particles that can impart sliding properties and have excellent long-term durability of sliding properties, and applications thereof. [Means for solving the problem]

[0006] As a result of diligent research, the inventors of the present invention discovered that the above problems can be solved if the resin particles are made of a thermoplastic resin containing a lubricant and have specific physical properties, and thus arrived at the present invention.

[0007] In other words, the present invention is a resin particle comprising a lubricant and a thermoplastic resin, wherein the extraction rate with n-hexane is 0 to 30%.

[0008] The resin particles of the present invention are polymers of a polymerizable component containing at least one selected from monomer (A) and monomer (B), wherein monomer (A) is a monomer having one polymerizable carbon-carbon double bond, and it is preferable that monomer (B) is a monomer having at least two polymerizable carbon-carbon double bonds. It is preferable that the polymerizable component of the resin particles of the present invention includes monomer (A) and monomer (B). It is preferable that the weight ratio of monomer (A) in the polymerizable component is 50 to 99.999% by weight, and the weight ratio of monomer (B) in the polymerizable component is 0.001 to 50% by weight. It is preferable that the resin particles of the present invention include at least one monomer selected from (meth)acrylate esters, monomers having a carboxyl group, nitrile-based monomers, monomers having an amide group, vinylidene chloride, vinyl ester-based monomers, and styrene-based monomers. It is preferable that the weight ratio of the lubricant in the entire resin particles is 5 to 70% by weight. It is preferable that the kinematic viscosity of the lubricant at 25°C is 10 to 100000 mm 2 / s. It is preferable that the lubricant of the resin particles of the present invention includes at least one selected from silicone oils, fluorine-based oils, ester-based oils, and hydrocarbon-based oils.

[0009] The composition of the present invention includes the above resin particles and a base material component. The molded article of the present invention is obtained by molding the above composition.

Effects of the Invention

[0010] The resin particles of the present invention impart slidability and are excellent in the long-term persistence of slidability. Since the composition of the present invention contains the above resin particles, a molded article having slidability, in which the slidability persists for a long period of time and has an excellent appearance, can be obtained. Since the molded article of the present invention is obtained by molding the above composition, it has slidability, the slidability is maintained for a long period of time, and it has an excellent appearance.

Embodiments for Carrying out the Invention

[0011] [Resin Particles] The resin particles of the present invention contain a lubricant and a thermoplastic resin, and it is sufficient that the lubricant is supported on the thermoplastic resin, the lubricant may be retained in pores, or the lubricant may be encapsulated in independent pores. From the viewpoint of enhancing the effect of long-term persistence of slidability, it is preferably a structure having one or more independent pores inside the thermoplastic resin, and it is preferably resin particles containing a lubricant in the pores inside. In particular, resin particles having a core-shell structure composed of an inclusion containing a lubricant as a core and a shell of a thermoplastic resin are preferable because they have high long-term persistence of slidability.

[0012] The resin particles of the present invention have an extraction rate with n-hexane of 0 to 30%. Resin particles having an extraction rate with n-hexane of 0 to 30% impart slidability and are excellent in the long-term persistence of slidability. When the extraction rate exceeds 30%, the long-term persistence of slidability is poor. The upper limit of the extraction rate is preferably in the order of (1) 25%, (2) 20%, (3) 15%, (4) 10%, (5) 8%, (6) 6% (the larger the number in parentheses, the more preferable). The extraction rate with n-hexane of the present invention means the one measured by the method described in the examples.

[0013] The thermoplastic resin contained in the resin particles of the present invention is a polymer of a polymerizable component containing at least one selected from monomer (A) and monomer (B), and monomer (A) is a monomer having one polymerizable carbon-carbon double bond, and it is preferable that monomer (B) is a monomer having at least two polymerizable carbon-carbon double bonds.

[0014] Examples of monomers (A) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, propyl (meth)acrylate, n-octyl (meth)acrylate, dodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, 2-chloroethyl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, (Meth)acrylic acid ester monomers such as benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate; monomers having a carboxyl group such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and carboxyethyl (meth)acrylate; monomers having a glycidyl group such as glycidyl (meth)acrylate and allyl glycidyl ether; acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronite Nitrile monomers such as nitrile monomers; acrylamide monomers such as acrylamide, substituted acrylamide, methacrylamide, substituted methacrylamide, and other acrylamide monomers, as well as maleimide monomers such as N-phenylmaleimide, N-(2-chlorophenyl)maleimide, N-cyclohexylmaleimide, and N-laurylmaleimide, and other monomers having amide bonds; vinylidene chloride; vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl butyrate; styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, and chlorostyrene; vinyl chloride, vinyl bromide Halogenated vinyl monomers such as vinyl fluoride; unsaturated monoolefin monomers such as ethylene, propylene, butylene, and isobutylene; vinyl ether monomers such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl isopropyl ether, vinyl butyl ether, vinyl isobutyl ether, vinyl-2-ethylhexyl ether, vinyl cyclohexyl ether, and vinyl-4-hydroxybutyl ether; vinyl ketone monomers such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone;Examples include N-vinyl monomers such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone, as well as vinylnaphthalene salts. For monomers having carboxyl groups, some or all of the carboxyl groups may be neutralized during polymerization. In this invention, (meth)acrylic means acrylic or methacrylic, and (meth)acrylate means acrylate or methacrylate. The above monomer (A) may be one or more in combination. Among these, the inclusion of at least one monomer selected from (meth)acrylic acid esters, monomers having a carboxyl group, nitrile monomers, monomers having an amide group, vinylidene chloride, vinyl ester monomers, and styrene monomers is preferable because it improves the strength of the resin fine particles. Furthermore, the inclusion of (meth)acrylic acid esters is preferable because the resin fine particles exhibit excellent dispersibility in the substrate.

[0015] Examples of monomers (B) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, Examples include di(meth)acrylates such as trimethylolpropane di(meth)acrylate, PEG#200 di(meth)acrylate, PEG#400 di(meth)acrylate, PEG#600 di(meth)acrylate, and neopentyl glycol di(meth)acrylate; tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; and butadiene. The above monomer (B) may be one or more in combination. Furthermore, the series of compounds referred to as "PEG#○○○ di(meth)acrylate" above are polyethylene glycol di(meth)acrylates, and it means that the average molecular weight of the polyethylene glycol portion is ○○○.

[0016] The Tg (Glass Transition Temperatures) of thermoplastic resins is not particularly limited, but is preferably -50°C to 250°C. The Tg of thermoplastic resins is described in the POLYMER HANDBOOK, etc., and in the case of polymers composed of two or more monomer components, it can be calculated from the ratio of constituent components. The upper limit of the Tg of thermoplastic resins is preferably in the order of (1) 220°C, (2) 200°C, (3) 170°C, (4) 150°C, and (5) 130°C (the higher the number in parentheses, the more preferable it is). On the other hand, the lower limit of the Tg of thermoplastic resins is preferably in the order of (1) -30°C, (2) -10°C, (3) 0°C, (4) 30°C, (5) 50°C, and (6) 100°C (the higher the number in parentheses, the more preferable it is).

[0017] It is preferable that the thermoplastic resin is a polymer of polymerizable components containing monomer (A) and monomer (B), as this improves the strength and heat resistance of the resin particles. This improvement in strength and heat resistance is particularly preferable because it suppresses the leakage of lubricant due to crushing of resin particles during molding.

[0018] The weight percentage of monomer (A) in the polymerizable component is not particularly limited, but is preferably 50 to 100% by weight. If the weight percentage of monomer (A) is less than 50% by weight, it may become difficult for the lubricant to be released from the resin particles. The upper limit of the weight percentage of monomer (A) is preferably in the following order: (1) 99.999% by weight, (2) 99.99% by weight, (3) 99.9% by weight, (4) 99.7% by weight, (5) 99.5% by weight, and (6) 99% by weight (the higher the number in parentheses, the more preferable it is). The lower limit of the weight percentage of monomer (A) is preferably in the following order: (1) 60% by weight, (2) 70% by weight, (3) 80% by weight, (4) 85% by weight, (5) 90% by weight, and (6) 93% by weight (the higher the number in parentheses, the more preferable it is).

[0019] The weight percentage of monomer (B) in the polymerizable component is not particularly limited, but is preferably 0 to 50% by weight. If the weight percentage of monomer (B) exceeds 50% by weight, it may become difficult for the lubricant to be released from the resin particles. The upper limit of the weight percentage of monomer (B) is preferably (1) 40% by weight, (2) 30% by weight, (3) 20% by weight, (4) 15% by weight, (5) 10% by weight, and (6) 7% by weight (the larger the number in parentheses, the more preferable it is). The lower limit of the weight percentage of monomer (B) is preferably (1) 0.001% by weight, (2) 0.01% by weight, (3) 0.1% by weight, (4) 0.3% by weight, (5) 0.5% by weight, and (6) 1% by weight (the larger the number in parentheses, the more preferable it is).

[0020] The lubricant contained in the resin particles of the present invention is a component that can impart sliding properties when released from the resin particles. Examples of lubricants include silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and modified silicone oil; fluorine oils such as fluoroethylene, trifluoroethylene chloride, perfluoropolyether, and perfluoropolyalkyl ether; diester oils such as dibutyl sebacate, di(2-ethylhexyl) sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, diisotridecyl adipate, ditridecyl glutarate, and methylacetyl lysinolate; trioctyl trimellitate, tridecyl trimellitate, tetraoctyl pyromelitate, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, and oligoesters of mixed fatty acids of monobasic and dibasic acids and polyhydric alcohols. Examples include ester oils such as complex ester oils; hydrocarbon oils such as normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, co-oligomer of 1-decene and ethylene, monoalkylbenzene, dialkylbenzene, polyalkylbenzene, monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene; ether oils such as polyethylene glycol, polypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, monoalkyltriphenyl ether, alkyldiphenyl ether, dialkyldiphenyl ether, tetraphenyl ether, pentaphenyl ether, monoalkyltetraphenyl ether, and dialkyltetraphenyl ether; graphite; molybdenum disulfide (MoS2); tungsten disulfide (WS2); boron nitride (BN); and polytetrafluoroethylene. Alternatively, a grease containing the above-mentioned oil and a thickener may be used as a lubricant. Examples of thickeners include common ones such as soap, urea, sodium terephthalate, organic bentonite, and silica gel. One or more of the above lubricants may be used in combination.

[0021] The lubricant preferably contains at least one selected from silicone oils, fluorine-based oils, ester-based oils, hydrocarbon-based oils, and ether-based oils in that the sliding property can be maintained for a long period. When the lubricant contains at least one selected from silicone oils, fluorine-based oils, ester-based oils, hydrocarbon-based oils, and ether-based oils, the total of their weight ratios is not particularly limited with respect to the whole lubricant, but is preferably 10% by weight or more, more preferably 20% by weight or more, still more preferably 30% by weight or more, particularly preferably 40% by weight or more, and most preferably 50% by weight or more, and the upper limit is 100% by weight.

[0022] The kinematic viscosity of the lubricant at 25°C is not particularly limited, but is preferably 10 to 100,000 mm 2 / s. When the kinematic viscosity of the lubricant is less than 10 mm 2 / s, the lubricant is likely to leak and may be inferior in long-term sustainability. On the other hand, when the kinematic viscosity of the lubricant exceeds 100,000 mm 2 / s, a strong external force is required for the lubricant to be released from the resin particles, and sufficient sliding property may not be obtained. The upper limit of the kinematic viscosity of the lubricant is preferably (1) 50,000 mm 2 / s, (2) 25,000 mm 2 / s, (3) 10,000 mm 2 / s, (4) 5,000 mm 2 / s in this order (the larger the number in the parentheses, the more preferable). On the other hand, the lower limit of the kinematic viscosity of the lubricant is preferably (1) 50 mm 2 / s, (2) 100 mm 2 / s, (3) 200 mm 2 / s, (4) 500 mm 2 / s, (5) 700 mm 2 / s, (6) 1000 mm 2 / s in this order (the larger the number in the parentheses, the more preferable). Two or more types of lubricants having different kinematic viscosities may be used in combination, and it is preferable that the kinematic viscosity when used in combination is within the above range. The kinematic viscosity of the lubricant at 25°C can be measured using, for example, an Ubbelohde viscometer.

[0023] The weight percentage of lubricant in the total resin particles is not particularly limited, but is preferably 5 to 70% by weight. If the weight percentage of lubricant is less than 5% by weight, sufficient sliding properties may not be provided. On the other hand, if the weight percentage of lubricant exceeds 70% by weight, the long-term durability of the sliding properties may be poor. The upper limit of the weight percentage of lubricant is preferably (1) 60% by weight, (2) 55% by weight, (3) 50% by weight, (4) 45% by weight, and (5) 40% by weight (the larger the number in parentheses, the more preferable it is). On the other hand, the lower limit of the weight percentage of lubricant is preferably (1) 10% by weight, (2) 13% by weight, (3) 15% by weight, (4) 18% by weight, and (5) 20% by weight (the larger the number in parentheses, the more preferable it is).

[0024] The resin particles of the present invention may contain, in addition to a lubricant, a component that vaporizes at low temperatures (hereinafter sometimes referred to as a vaporizing component). Including a vaporizing component is preferable because it allows for more efficient release of the lubricant. Examples of vaporized components include hydrocarbons such as propane, (iso)butane, (iso)pentane, (iso)hexane, (iso)heptane, and (iso)octane; halides of hydrocarbons such as methyl chloride, methylene chloride, chloroform, and carbon tetrachloride; and compounds that generate gas through thermal decomposition upon heating, such as azodicarbonamide, N,N'-dinitrosopentamethylenetetramine, and 4,4'-oxybis(benzenesulfonyl hydrazide).

[0025] The boiling point of the vaporized component is not particularly limited, but is preferably -30 to 150°C. The upper limit of the boiling point of the vaporized component is more preferably 130°C, even more preferably 110°C, particularly preferably 100°C, and most preferably 80°C. On the other hand, the lower limit of the boiling point of the vaporized component is more preferably -15°C, even more preferably -5°C, particularly preferably 0°C, and most preferably 5°C. The weight ratio of the vaporized component is not particularly limited, but is preferably 0 to 400 parts by weight per 100 parts by weight of lubricant. The upper limit of the weight ratio is more preferably 300 parts by weight, even more preferably 200 parts by weight, and particularly preferably 100 parts by weight. The lower limit of the weight ratio is more preferably 1 part by weight, even more preferably 5 parts by weight, and particularly preferably 10 parts by weight.

[0026] The weight percentage of lubricant-containing inclusions in the total resin particles (hereinafter sometimes referred to as the inclusion rate) is not particularly limited, but is preferably 5 to 80% by weight. If the inclusion rate is less than 5% by weight, sufficient sliding properties may not be provided. On the other hand, if the inclusion rate exceeds 80% by weight, the long-term durability of the sliding properties may be poor. The upper limit of the inclusion rate is preferably in the following order: (1) 70% by weight, (2) 60% by weight, (3) 55% by weight, (4) 50% by weight, (5) 45% by weight, and (6) 40% by weight (the higher the number in parentheses, the more preferable it is). On the other hand, the lower limit of the inclusion rate is preferably in the following order: (1) 10% by weight, (2) 13% by weight, (3) 15% by weight, (4) 18% by weight, and (5) 20% by weight (the higher the number in parentheses, the more preferable it is).

[0027] The average particle diameter of the resin particles of the present invention is not particularly limited, but is preferably 0.1 to 200 μm. If the average particle diameter of the resin particles is less than 0.1 μm, sufficient sliding properties may not be provided. On the other hand, if the average particle diameter of the resin particles is greater than 200 μm, the long-term durability of the sliding properties may be poor. The upper limit of the average particle diameter of the resin particles is preferably (1) 150 μm, (2) 120 μm, (3) 100 μm, (4) 75 μm, (5) 60 μm, (6) 50 μm, and (7) 45 μm, in that order (the larger the number in parentheses, the more preferable). On the other hand, the lower limit of the average particle diameter of the resin particles is preferably (1) 0.5 μm, (2) 1 μm, (3) 3 μm, (4) 5 μm, and (5) 10 μm, in that order (the larger the number in parentheses, the more preferable). Note that the average particle diameter of the resin particles of the present invention refers to the particle diameter measured by the method described in the examples.

[0028] [Method for manufacturing resin particles] The resin particles of the present invention are not particularly limited in their manufacturing method and can be produced by, for example, emulsion polymerization, suspension polymerization, liquid drying, spray drying, etc. Among these methods, a method of obtaining resin particles by mixing a polymerizable monomer with a lubricant and performing suspension polymerization in an aqueous dispersion medium is particularly preferred.

[0029] The resin particles of the present invention are preferably manufactured using a method comprising a step (polymerization step) in which a polymerizable component containing at least one selected from monomer (A) having one (radical) polymerizable carbon-carbon double bond and monomer (B) having at least two (radical) polymerizable carbon-carbon double bonds, and an oily mixture containing a lubricant are dispersed in an aqueous dispersion medium, thereby polymerizing the polymerizable component. The oily mixture may contain polymers and vaporizable components in addition to the polymerizable component and lubricant.

[0030] In the polymerization process, it is preferable to polymerize the polymerizable components in the presence of a polymerization initiator. The polymerization initiator is preferably included in the oily mixture along with the polymerizable components and lubricant. Examples of polymerization initiators include peroxides such as peroxydicarbonate, peroxyester, and diacyl peroxide; azo compounds such as azonitrile, azoester, azoamide, azoalkyl, and polymer azo initiator; and redox initiators. These polymerization initiators may be used individually or in combination of two or more. Oil-soluble polymerization initiators that are soluble in polymerizable components are preferred as polymerization initiators. The amount of polymerization initiator used is not particularly limited, but is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, and even more preferably 0.2 to 5 parts by weight, per 100 parts by weight of polymerizable component.

[0031] Aqueous dispersion media are prepared, for example, by adding dispersion stabilizers, dispersion stabilization aids, polymerization aids, electrolytes, etc., to water (ion-exchanged water) as needed. Regarding the resin particles of the present invention, it is preferable to add a dispersion stabilizer to stabilize the droplets and control the particle size in the manufacturing method. The dispersion stabilizer is not particularly limited, but organic and inorganic dispersion stabilizers are preferred. Examples of organic dispersion stabilizers include fine particle stabilizers, water-soluble polymers, and nanocellulose. Examples of fine particle stabilizers include those used in Pickering emulsions. Examples of water-soluble polymers include polyvinyl alcohol, methylcellulose, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, and polyacrylic acid. Examples of inorganic dispersion stabilizers include clay minerals, tricalcium phosphate, magnesium pyrophosphate obtained by the double decomposition method, calcium pyrophosphate, colloidal silica, alumina sol, and magnesium hydroxide. These dispersion stabilizers may be used individually or in combination of two or more. The amount of dispersion stabilizer used is preferably 0.05 to 100 parts by weight, more preferably 0.2 to 70 parts by weight, per 100 parts by weight of the oil-soluble component.

[0032] Further dispersion stabilization aids may be used to control droplet stability and particle size. Examples of dispersion stabilization aids include polymer-type dispersion stabilization aids, cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants. These dispersion stabilization aids may be used individually or in combination of two or more types.

[0033] The aqueous dispersion medium may contain an electrolyte. Examples of electrolytes include sodium chloride, magnesium chloride, calcium chloride, sodium sulfate, magnesium sulfate, ammonium sulfate, and sodium carbonate. These electrolytes may be used individually or in combination of two or more. The electrolyte content is not particularly limited, but is preferably 0.1 to 50 parts by weight per 100 parts by weight of aqueous dispersion medium.

[0034] The aqueous dispersion medium may contain polymerization aids. Using polymerization aids can suppress the aggregation of resin particles and the formation of scale in the polymerization reactor. Examples of polymerization aids include nitrites, sodium sulfites, copper chloride, iron chloride, dichromate, stannic chloride, hydroquinone, ethylenediaminetetraacetate, water-soluble ascorbic acid, water-soluble polyphenols, and water-soluble vitamin B compounds. These polymerization aids may be used individually or in combination of two or more.

[0035] In the polymerization process, the oily mixture is dispersed in an aqueous dispersion medium so that spherical oil droplets of a predetermined particle size are prepared. Methods for dispersing the oily mixture include, for example, stirring with a homomixer (e.g., manufactured by Primix Corporation), using a static dispersion device such as a static mixer (e.g., manufactured by Noritake Engineering Co., Ltd.), membrane suspension, ultrasonic dispersion, and other common dispersion methods. Next, polymerization is initiated by heating the dispersion in which the oily mixture is dispersed as spherical oil droplets in an aqueous dispersion medium. During the polymerization reaction, it is preferable to stir the dispersion, and the stirring should be done gently, for example, to prevent the oily mixture and the polymerized resin particles from floating or settling.

[0036] The polymerization temperature can be freely set depending on the type of polymerization initiator, but it is preferably controlled within the range of 30 to 100°C, more preferably 40 to 90°C. The time for maintaining the reaction temperature is preferably about 1 to 20 hours. There are no particular limitations on the initial polymerization pressure, but it is preferably in the range of 0 to 5 MPa, more preferably 0.02 to 3 MPa in gauge pressure.

[0037] The resin particles of the present invention may be in the form of a slurry, a wet powder, or a dry powder. When the resin particles of the present invention are in the form of a wet powder, for example, they can be obtained by dewatering a slurry containing the resin particles obtained by the above manufacturing method using a centrifuge, a pressure press, a vacuum dewaterer, etc. The moisture content of such a wet powder is not particularly limited, but is usually 10 to 50% by weight, preferably 15 to 45% by weight, and more preferably 20 to 40% by weight. Furthermore, the wet powder obtained above can be dried using a shelf dryer, indirect heating dryer, fluidized bed dryer, vacuum dryer, vibrating dryer, airflow dryer, etc., to obtain a dry powder. Alternatively, the slurry may be dried using a spray dryer, fluidized bed dryer, etc., to obtain a dry powder.

[0038] [Composition] The composition of the present invention comprises the above-mentioned resin particles and base material components, and a molded article can be obtained that has sliding properties, maintains sliding properties for a long period of time, and has an excellent appearance. The base components include, for example, rubbers such as natural rubber, isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber, silicone rubber, acrylic rubber, urethane rubber, fluororubber, polyether rubber, ethylene-propylene rubber (EPM), and ethylene-propylene-diene rubber (EPDM); thermosetting resins such as epoxy resins, phenolic resins, unsaturated polyester resins, polyurethanes, polyimides, and polyamide-imides; waxes such as polyethylene wax and paraffin wax; ethylene-vinyl acetate copolymer (EVA), polyethylene (PE), modified polyethylene, polypropylene (PP), modified polypropylene, modified polyolefin, polyvinyl chloride (PVC), acrylic resin, thermoplastic polyurethane, acrylonitrile-styrene copolymer (AS resin), and acrylonitrile-butadiene rubber. Examples include thermoplastic resins such as ethylene-styrene copolymer (ABS resin), polystyrene (PS), (meth)acrylate-styrene copolymer, polyamide resin (nylon 6, nylon 66, etc.), modified polyamide, polycarbonate, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyacetal (POM), polyphenylene sulfide (PPS), polyphenylene ether (PPE), modified polyphenylene ether, and fluororesin; ionomer resins such as ethylene-based ionomer, urethane-based ionomer, styrene-based ionomer, and fluorine-based ionomer; thermoplastic elastomers such as olefin-based elastomer, styrene-based elastomer, urethane-based elastomer, polyester-based elastomer, polyamide-based elastomer, and fluorine-based elastomer; and bioplastics such as polylactic acid (PLA), cellulose acetate, PBS, PHA, and starch resin. One or more of these base components may be used in combination. In addition to resin particles and base components, the composition of the present invention may also contain additives such as flame retardants, antioxidants, ultraviolet absorbers, stabilizers, fillers, plasticizers, pigments, and antistatic agents, as well as solvents, lubricants, resin particles other than those of the present invention, organic powders, inorganic powders, etc., depending on the application.

[0039] The amount of resin particles contained in the composition of the present invention is not particularly limited, but is preferably 0.1 to 400 parts by weight per 100 parts by weight of the base component. The lower limit of the resin particle content is more preferably 0.3 parts by weight, even more preferably 0.5 parts by weight, and particularly preferably 1 part by weight. The upper limit of the resin particle content is more preferably 250 parts by weight, even more preferably 150 parts by weight, and particularly preferably 100 parts by weight. It is preferable that the resin particle content be within the above range, as this allows for the production of a molded article with sufficient sliding properties and excellent long-term durability of sliding properties.

[0040] The composition can be obtained, for example, by mixing resin particles, a base component, and various additives as needed. Alternatively, a composition (masterbatch) containing resin particles and a base component can be prepared, and then further mixed with the base component to form the final composition. Mixing methods include, for example, mixing and stirring machines, mixers, Henschel mixers, super mixers, ribbon mixers, ribbon blenders, kneaders, rolls, mixing rolls, single-screw kneaders, twin-screw kneaders, multi-screw kneaders, etc.

[0041] The molded article of the present invention is obtained by molding the above composition. Depending on whether the resin is thermoplastic or thermosetting, a wide range of commonly used molding methods can be employed, such as extrusion molding, injection molding, vacuum molding, blow molding, compression molding, transfer molding, RIM molding, and casting. The amount of resin particles contained in the molded article of the present invention is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 15 parts by weight, even more preferably 0.5 to 10 parts by weight, and most preferably 1 to 8 parts by weight, per 100 parts by weight of the base material component.

[0042] Because the molded articles of the present invention possess excellent sliding properties, they can be widely used industrially as components in various fields such as automobiles, building materials, office automation equipment, home appliances, and electronic devices. In particular, they can be suitably used as sealing materials for vehicles and buildings.

Example

[0043] Hereinafter, examples of the resin particles of the present invention will be specifically described. Note that the present invention is not limited to these examples. The measurement methods, evaluation items, and evaluation methods of physical properties in the examples and comparative examples are as shown below. Hereinafter, “%” and “parts” may respectively mean “% by weight” and “parts by weight”. Also, Example 6 、 8 and 9 is a reference example.

[0044] <Average particle diameter of resin particles> It was measured using a laser diffraction scattering particle size analyzer (Microtrac ASVR, manufactured by Nikkiso Co., Ltd.), and the volume-based cumulative 50% particle diameter (D50) was taken as the average particle diameter.

[0045] <Weight ratio of inclusions in the whole resin particles (inclusion rate)> 1.0 g of dried resin particles was placed in a stainless steel evaporation dish with a diameter of 80 mm and a depth of 15 mm, and its weight was measured (W1 (g)). 30 mL of acetonitrile was added and uniformly dispersed, and after leaving it to soak at room temperature for 24 hours, it was dried under reduced pressure at 130°C for 2 hours, and its weight was measured (W2 (g)). After the sample after drying under reduced pressure was washed 3 times with 30 mL of n-hexane, it was dried at 100°C for 10 minutes, and its weight was measured (W3 (g)). Also, the moisture content of the dried resin particles was measured using a Karl Fischer moisture meter (MKA-510N type, manufactured by Kyoto Electronic Industry Co., Ltd.), and C w (% by weight) was taken. From the above W1, W3, C w the weight ratio of inclusions in the whole resin particles (inclusion rate) (C (% by weight)) was calculated from the following formula (1). C = 100×[(W1 - W3) - C W / 100] / (1.0 - C W / 100) (1)

[0046] <Extraction rate by n-hexane> 1.0 g of dried resin particles were mixed with 30 mL of n-hexane and shaken at 25°C for 5 minutes to uniformly disperse. After immersion, the resin particles and n-hexane extract were separated by filtration. The same procedure was repeated twice for the filtered resin particles. The resulting resin particles were dried at 100°C for 10 minutes, and their weight was measured (W4(g)). C above W From W4, the weight loss rate (E (weight %)) due to immersion in n-hexane was calculated using the following formula (2). E = 100 × (1.0 - W4 - C) W / 100) / (1.0-C W (2) / 100) Extraction rate by n-hexane (C E The percentage (%) was calculated from the inclusion rate (C (weight %)) and the weight loss rate due to immersion in n-hexane (E (weight %)) using the following formula (3). C E = 100 × E / C (3)

[0047] <Evaluation of Sliding Properties> Three parts of the obtained resin particles were mixed with 97 parts of Milastomer 8032BS (manufactured by Mitsui Chemicals, Inc., a thermoplastic olefin-based elastomer) to obtain the composition. Next, using a laboplast mill (twin-screw extruder ME-25, manufactured by Toyo Seiki Kogyo Co., Ltd.) and a T-die (lip width 150 mm, thickness 0.7 mm), the setting temperature (molding temperature) of the extruder and T-die was set to 180°C, and the screw rotation speed was set to 50 rpm. The obtained composition was fed into the raw material hopper of a laboplast mill to create a molded sheet. The coefficient of dynamic friction of the prepared sheet was measured using a friction tester (FRICTION TESTER TR-2, manufactured by Toyo Seiki Kogyo Co., Ltd.) at a measurement speed of 100 mm / min, and the sliding properties imparted to the resin particles were evaluated according to the following criteria. The coefficient of dynamic friction for the sheet without resin particles was 0.92. ○○○: Has a dynamic friction coefficient of less than 0.5 and provides excellent sliding properties. ○○: The coefficient of dynamic friction is 0.5 or higher and less than 0.65, and it has a good sliding effect. ○: The coefficient of dynamic friction is 0.65 or higher and less than 0.8, indicating a moderately good sliding effect. ×: The coefficient of dynamic friction is 0.8 or higher, resulting in poor sliding effect.

[0048] <Sliding Resistance Evaluation 1> The surface of the sheet evaluated in the above sliding properties evaluation was wiped with a dry cloth using the friction measuring instrument used in the above sliding properties evaluation until the dynamic friction coefficient at a measurement speed of 100 mm / min was 0.85 to 0.95, and the sheet was stored at 40°C for one month. The dynamic friction coefficient of the sheet after storage was measured at a measurement speed of 100 mm / min using the friction measuring instrument used in the above sliding properties evaluation, and the sliding properties persistence evaluation of the resin particles (sliding properties persistence evaluation 1) was performed according to the following criteria. ○○: Has a kinetic friction coefficient of less than 0.4 and exhibits excellent sustained sliding properties. ○: The coefficient of dynamic friction is between 0.4 and 0.6, indicating slightly superior sliding performance. △: The coefficient of dynamic friction is between 0.6 and 0.8, resulting in slightly inferior sliding performance. ×: The coefficient of dynamic friction is 0.8 or higher, resulting in poor sustained sliding performance.

[0049] <Sliding Resistance Evaluation 2> The surface of the sheet evaluated in the above-mentioned sliding properties durability evaluation 1 was wiped with a dry cloth using the friction measuring instrument used in the above-mentioned sliding properties imparting evaluation until the dynamic friction coefficient at a measurement speed of 100 mm / min was 0.85 to 0.95, and the sheet was stored at 40°C for one month. The dynamic friction coefficient of the sheet after storage was measured at a measurement speed of 100 mm / min using the friction measuring instrument used in the above-mentioned sliding properties imparting evaluation, and the sliding properties durability evaluation of the resin particles (sliding properties durability evaluation 2) was performed according to the following criteria. ○○: Has a kinetic friction coefficient of less than 0.4 and exhibits excellent sustained sliding properties. ○: The coefficient of dynamic friction is between 0.4 and 0.6, indicating slightly superior sliding performance. △: The coefficient of dynamic friction is between 0.6 and 0.8, resulting in slightly inferior sliding performance. ×: The coefficient of dynamic friction is 0.8 or higher, resulting in poor sustained sliding performance.

[0050] <Evaluation of the dispersibility of resin particles> The created sheets were visually inspected, and the dispersibility of the resin particles was evaluated according to the following criteria: ○: No visible clumps of resin particles were observed. ×: Many visible clumps of resin particles are observed due to aggregation.

[0051] <Visual evaluation of molded products> After storing the prepared sheets at 40°C for two months, the sheet surface was visually inspected, and the appearance of the molded product was evaluated according to the following criteria. The blank sheet was a sheet molded using only Milastomer 8032BS without any additives. ○: Indistinguishable from the blank in appearance, and superior in appearance. △: Shine and wetness from liquids were observed, resulting in a slightly inferior appearance. ×: Discoloration such as whitening was observed, resulting in an inferior appearance.

[0052] (Example 1) 140 parts methyl methacrylate, 2 parts ethylene glycol dimethacrylate, 1.5 parts dilaurolyl peroxide, dimethylpolysiloxane (silicone KF-96-100cs, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C 100 mm) 2 63 parts of / s were mixed to prepare an oily mixture. Separately, 550 parts of deionized water, 110 parts of sodium chloride, 0.8 parts of polyvinylpyrrolidone, and 60 parts of colloidal silica containing 20% ​​by weight of the active ingredient were added, and the pH was adjusted to 2-4 to prepare an aqueous dispersion medium. An aqueous dispersion medium and an oily mixture were mixed, and the resulting mixture was stirred in a homomixer to prepare a suspension. This suspension was polymerized at 70°C for 6 hours in a polymerization vessel pressurized to 0.3 MPa with nitrogen gas. Resin particles were produced by filtering and drying the product obtained after polymerization. The physical properties of the produced resin particles were measured and the resin particles were evaluated using the method described above. The results are shown in Tables 1 and 3.

[0053] (Examples 2-13) Resin particles were obtained in the same manner as in Example 1, except that the oily mixture was changed to those shown in Tables 1 and 2. The physical properties of the obtained resin particles were measured and evaluated in the same manner as in Example 1. The results are shown in Tables 1 to 4. The kinematic viscosity of the lubricant used in Example 11 at 25°C was 400 mm². 2 It was / s.

[0054] [Table 1]

[0055] [Table 2]

[0056] The details of the abbreviations for the raw materials used, as listed in Tables 1 and 2, are shown below. EDMA: Ethylene glycol dimethacrylate TMP: Trimethylolpropane trimethacrylate 1,9ND-A:1,9-nonanediol diacrylate KF-96-100cs: Silicone KF-96-100cs, dimethylpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C is 100 mmHg. 2 / s KF-96-1000cs: Silicone KF-96-1000cs, dimethylpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C is 1000 mmHg. 2 / s KF-96H-10,000 cs: Silicone KF-96H-10,000 cs, dimethylpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C is 10,000 mmHg. 2 / s KF-96H-100,000 cs: Silicone KF-96H-100,000 cs, dimethylpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C is 100,000 mmHg. 2 / s Fluorine oil: 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, Ester oil: Diisotridecyl adipate, kinematic viscosity at 25°C is 250 mmHg. 2 / s The abbreviations listed above also indicate the respective raw materials in the following descriptions.

[0057] (Example 14) 85 parts of Milastomer 8032BS and 15 parts of the resin particles obtained in Example 1 were kneaded in a twin-screw kneader and cut into pellets to prepare a masterbatch. Next, 80 parts of Milastomer 8032BS and 20 parts of the prepared masterbatch were mixed to obtain a mixture. Using the obtained mixture, a sheet was prepared by molding in the same manner as described in the sliding properties evaluation above. The sliding properties of the prepared sheet, sliding properties duration evaluation 1, sliding properties duration evaluation 2, and appearance evaluation of the molded body, as well as the dispersibility evaluation of the resin particles, were performed in the same manner as in Example 1. The results are shown in Table 4.

[0058] (Comparative Examples 1 and 2) Resin particles were obtained in the same manner as in Example 1, except that the oily mixture was changed to those shown in Table 2. The physical properties of the obtained resin particles were measured and evaluated in the same manner as in Example 1. The results are shown in Table 4.

[0059] (Comparative Example 3) 3.5 g of polyethylene maleic anhydride was dissolved in 50 g of deionized water, and the pH was adjusted to approximately 4 to obtain an aqueous mixture. 35 g of dimethylpolysiloxane (KF-96-1000cs) was added to this aqueous mixture and stirred to prepare an emulsion. A mixed solution of 6 g of melamine adjusted to pH 12 and 11 g of 37% formaldehyde aqueous solution was added to this emulsion, and the pH was adjusted to approximately 4. Interfacial polymerization was carried out at 80°C for 3 hours, and the resin particles obtained after polymerization were filtered and dried. The average particle size of the obtained resin particles was 8 μm. Using the obtained resin particles, a sheet was prepared by molding in the same manner as described in the sliding properties evaluation above. The sliding properties of the prepared sheet, sliding properties duration evaluation 1, sliding properties duration evaluation 2, and appearance evaluation of the molded body, as well as the dispersibility evaluation of the resin particles, were performed in the same manner as in Example 1. The results are shown in Table 4.

[0060] (Comparative Example 4) A mixture was obtained by mixing 99 parts of Milastomer 8032BS with 1 part of KF-96-100cs. Using the obtained mixture, a sheet was prepared by molding in the same manner as described in the sliding properties evaluation above. The sliding properties evaluation of the prepared sheet, sliding properties duration evaluation 1, sliding properties duration evaluation 2, and appearance evaluation of the molded body were performed in the same manner as in Example 1. The results are shown in Table 4.

[0061] [Table 3]

[0062] [Table 4]

[0063] Tables 3-4 show that the resin particles in this invention impart sliding properties and exhibit excellent long-term durability of sliding properties. Furthermore, they also exhibit excellent dispersibility in molded articles. On the other hand, Comparative Example 1, which does not contain a lubricant, does not provide sufficient sliding properties. Furthermore, while Comparative Example 2, which consists of resin particles with an n-hexane extraction rate of more than 30%, and Comparative Example 3, which consists of lubricant-encapsulated particles made of thermosetting resin, exhibit excellent initial sliding properties, their long-term durability is insufficient.

[0064] According to the present invention, resin particles are provided that impart sliding properties, exhibit excellent long-term durability of sliding properties, and also have excellent dispersibility in molded articles. The molded article according to the present invention has sliding properties, maintains sliding properties for a long period of time, and has an excellent appearance.

Claims

1. Resin particles containing a lubricant and a thermoplastic resin, The resin particles have one or more independent pores inside the thermoplastic resin, and the pores contain the lubricant. The thermoplastic resin is a polymer of polymerizable components comprising monomer (A), which is a monomer having one polymerizable carbon-carbon double bond, and monomer (B), which is a monomer having at least two polymerizable carbon-carbon double bonds. The monomer (A) is at least one monomer selected from (meth)acrylic acid esters, monomers having a carboxyl group, and nitrile monomers. The weight percentage of monomer (A) in the polymerizable component is 93 to 99.7% by weight, and the weight percentage of monomer (B) in the polymerizable component is 0.3 to 7% by weight. The lubricant comprises at least one selected from silicone-based oils, fluorine-based oils, and ester-based oils. The silicone oil is at least one selected from dimethyl silicone oil and methylphenyl silicone oil. The ester oil is at least one selected from dibutyl sebacate, di(2-ethylhexyl) sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, diisotridecyl adipate, ditridecyl glutarate, methylacetyl lysinolate, trioctyl trimellitate, tridecyl trimellitate, tetraoctyl pyromelitate, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate. The kinematic viscosity of the lubricant at 25°C is 50 to 100,000 mm². ２ / s, The weight ratio of the lubricant to the total resin particles is 5 to 60% by weight. The average particle size of the aforementioned resin particles is 10 to 200 μm. Resin particles having an extraction rate of 1.0 to 30% with n-hexane.

2. The resin particles according to claim 1, wherein the weight ratio of monomer (A) to the polymerizable component is 93 to 98.592% by weight, and the weight ratio of monomer (B) to the polymerizable component is 1.408 to 7% by weight.

3. The resin particles according to claim 1 or 2, wherein the average particle diameter is 10 to 50 μm.

4. The kinematic viscosity of the lubricant at 25°C is 100 to 100,000 mm². ２ Resin particles according to any one of claims 1 to 3, wherein the particle size is / s.

5. The resin particles according to any one of claims 1 to 4, wherein the lubricant is at least one selected from the silicone-based oil, the fluorine-based oil, and the ester-based oil.

6. Resin particles according to any one of claims 1 to 5, which are for use as a sealing material for vehicles or for use as a sealing material for buildings.

7. A composition comprising resin particles according to any one of claims 1 to 6 and a base material component.

8. A molded article obtained by molding the composition described in claim 7.

Images