JP2010285506A - Resin powder for powder slush molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin powder for powder slush molding which can provide a powder slush molded product compatible in suppression of color unevenness and heat resistance with good balance, and to provide the powder slush molded product using the resin powder. <P>SOLUTION: This resin powder for powder slush molding is produced by drying a resin powder using dehumidified air having a moisture content of ≤0.010 kg/kg. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin powder used for powder slush molding. Furthermore, the present invention relates to a powder slush molded body using the resin powder.

  An example of a method for molding a skin material constituting an interior material or the like is a powder slush molding method which is a molding method using a powder resin. In this method, i) a soft tactile product can be obtained, ii) leather texture and stitches can be provided on the product, iii) a high-quality skin material with a high degree of design freedom and high designability can be formed. , Etc., and is widely used for the skin molding of automobile interior parts such as instrument panels, console boxes and door rims.

  Conventionally, vinyl chloride (PVC) has been used as the powder slush molding resin powder. However, since PVC contains halogen, there is a problem that the load on the environment is large. Therefore, in recent years, resin powders mainly composed of thermoplastic polyurethane elastomers (TPU) have been used as materials not containing halogen. However, the use of TPU is limited when weather resistance and flexibility are required.

  A resin powder made of an acrylic thermoplastic elastomer has been proposed as a material for overcoming the above problems. Molded products obtained from this resin contain almost no halogen and are excellent in flexibility, mechanical properties, heat resistance, low temperature properties, strain recovery properties, and resistance to drugs that can be contacted, which are properties required for skin materials. ing.

  The powder slush molding method is a method in which resin powder is poured into a heated mold, melt-molded, and then cooled and solidified into a desired shape. Unlike other molding methods such as injection molding, this method does not apply shaping pressure at the time of molding, so the resin powder has a powder flowability for quickly filling a mold having a complicated shape, Good heat-meltability is required for forming into a desired shape under no pressure. Furthermore, if the resins block during storage, the molded body will be uneven and the appearance will be impaired, so blocking resistance is also required.

  In addition, the powder slush molding method is characterized by using a high-temperature mold heated as described above and molding in a short time (several tens of seconds). It creates voids in the body, causing pinholes and uneven color on the surface. Although the volatile content in the resin is reduced by a drying step or the like, the drying at a high temperature may cause mutual adhesion due to an increase in the resin temperature, and there is a concern that the blocking property and the fluidity may be lowered. In addition, due to the influence of seasonal fluctuations (especially in summer), moisture is absorbed when the product is cooled, and the volatile matter is increased from the end of drying.

  The increase in volatile content in the resin is mostly due to moisture absorption from the outside air, and as a result, the end user may use a storage place with air conditioning or take measures to prevent moisture absorption with instrument air. Many. Moreover, a method for suppressing moisture absorption during molding by adding a device to the molding apparatus is also known (Patent Document 1).

  However, these measures are intended to suppress moisture absorption (maintenance of the current situation) and not to reduce the initial volatile content. If these measures are taken to reduce the volatile content, restrictions such as the air conditioning method, the humidity of the instrumentation air, the air volume, etc. will occur, and the burden on the end user will be considerable.

  For this reason, there has been a demand for a method for stably obtaining a molded body without imposing a burden on the end user and without being affected by seasonal fluctuations.

JP 2005-345048 A

  The objective of this invention is providing the resin powder which can obtain the powder slush molding which balances uneven color suppression and heat resistance in good balance.

  As a result of intensive studies, the present inventors have solved the above problems.

  That is, the present invention relates to a resin powder for powder slush molding, which is dried with dehumidified air having a moisture content of 0.010 kg / kg or less.

  As a preferred embodiment, the present invention relates to a resin powder characterized in that weight loss by a heat-drying moisture meter (set temperature 120 ° C.) is 0.40% or less.

  In a preferred embodiment, the resin powder includes at least one resin selected from the group consisting of urethane resins, ester resins, epoxy resins, vinyl chloride resins, and acrylic resins. It relates to resin powder.

  As a preferred embodiment, the present invention relates to a resin powder characterized in that the resin powder contains an acrylic block copolymer (A).

  As a preferred embodiment, the resin powder includes an acrylic block copolymer (A), an acrylic polymer (B), and a plasticizer (C). However, the acrylic block copolymer (A) is composed of a methacrylic polymer block (a) mainly composed of a methacrylic polymer and an acrylic polymer block (b) mainly composed of an acrylic polymer. An acrylic block copolymer having an acid anhydride group and / or a carboxyl group in at least one of the methacrylic polymer block (a) and the acrylic polymer block (b). The acrylic polymer (B) is an acrylic polymer having at least 1.1 epoxy groups in one molecule, and the plasticizer (C) is a trimellitic acid ester compound and / or pyromellitic acid. It is a plasticizer made of an ester compound.

  As a preferred embodiment, the present invention relates to a resin powder characterized in that the resin powder is coated with a polymer latex. However, the polymer latex is obtained by an emulsion polymerization method using a thioglycolic acid compound as a chain transfer agent, a persulfuric acid compound as a polymerization initiator, and an anionic surfactant as an emulsifier, and forms a latex. Is a polymer latex having a glass transition temperature of 75 ° C. or higher and a weight average molecular weight of 40,000 to 100,000.

  A preferred embodiment relates to a resin powder characterized in that an acid anhydride group and / or a carboxyl group are present in the main chain of the acrylic polymer block (b).

  As a preferred embodiment, the acrylic block copolymer (A) comprises 10 to 60% by weight of a methacrylic polymer block (a) containing a methacrylic monomer as a main component, and an acrylic monomer. The present invention relates to a resin powder comprising 90 to 40% by weight of an acrylic polymer block (b) as a main component.

  As a preferred embodiment, the acrylic polymer block (b) is at least one selected from the group consisting of -n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate. The present invention relates to a resin powder comprising 50 to 100% by weight of a monomer and 50 to 0% by weight of a vinyl monomer copolymerizable therewith.

  As a preferred embodiment, the methacrylic polymer block (a) relates to a resin powder characterized by having a glass transition temperature of 25 to 130 ° C.

  A preferred embodiment relates to a resin powder characterized in that the acrylic block copolymer (A) has a number average molecular weight measured by gel permeation chromatography of 30,000 to 200,000.

  As a preferred embodiment, the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography of the acrylic block copolymer (A) is 1.8 or less. It is related with the resin powder characterized by being.

  A preferred embodiment relates to a resin powder characterized in that the acrylic polymer (B) has a weight average molecular weight of 30,000 or less.

  As a preferred embodiment, the present invention relates to a resin powder characterized in that the acrylic block copolymer (A) comprises a block copolymer produced by an atom transfer radical polymerization method.

  As a preferred embodiment, the present invention relates to a resin powder characterized in that the plasticizer (C) is 0.1 to 30 parts by weight with respect to 100 parts by weight of the acrylic block copolymer (A).

  The present invention also relates to a powder slush molded body using the above-described resin powder.

  The present invention also relates to an automobile interior skin characterized by using the above-described resin powder.

  The resin powder of the present invention can provide a molded product that balances color unevenness suppression and heat resistance in a well-balanced manner by powder slush molding. The molded body according to the present invention can be suitably used, for example, for an automobile interior skin having excellent appearance.

  Hereinafter, the present invention will be described in more detail.

  The present invention is a resin powder used for powder slush molding, which is dried with dehumidified air having a water content of 0.010 kg / kg or less.

<Dehumidification method>
The dehumidified air used for drying the resin powder needs to be dehumidified to 0.010 kg / kg or less, preferably 0.008 kg / kg or less, more preferably 0.006 kg / kg or less. It is. The unit (kg / kg) here means the weight (Kg) of water contained in 1 kg of dry air.

  The time required for dehumidification is approximately 2 hours, but it varies depending on the moisture content and flow rate of the dehumidification air used, the amount of resin powder to be dehumidified, and the like, and it is desirable to adjust as necessary. In particular, if the flow rate is adjusted too much, there is a concern that the air will blow out and the dehumidification efficiency will drop, or that the resin will be entrained and discharged out of the system, if it is too small, it will be dehumidified locally and become non-uniform Problems arise. The specific flow rate needs to be adjusted according to the conditions (such as the shape and capacity of the container, the particle diameter and amount of the resin powder) in which dehumidified air is used.

  The temperature at which the dehumidified air is used is preferably near room temperature. When dehumidified air is created using a compressor or the like, the atmosphere is heated by the compression, although it varies depending on the atmospheric temperature and weather. For this reason, the dehumidified air is usually used after cooling to about 10 to 30 ° C.

  The resin powder of the present invention preferably has a weight loss of 0.40% or less by a heat drying moisture meter (set temperature: 120 ° C.). Further, if it exceeds 0.40%, color unevenness occurs, which is not preferable. The heat-drying moisture meter here can be heated in a short time (several minutes) by using a halogen lamp as a heater, and can be reproduced with high accuracy by using a mass sensor used in an analytical balance. It is a device that can perform good measurements. Generally, it is used for the measurement of moisture content and solid content of resin and the like, for example, a heat drying moisture meter (MS-70 type) manufactured by A & D Corporation.

<Resin>
There is no restriction | limiting in particular as resin powder used for powder slush molding, According to the required characteristic, it can select. Among these, the resin powder preferably contains at least one resin selected from the group consisting of urethane resins, ester resins, epoxy resins, vinyl chloride resins, and acrylic resins. Acrylic resins are preferred because they are excellent in flexibility, mechanical properties, heat resistance, low temperature properties, strain recovery properties, resistance to contactable drugs, etc. It is preferable to contain a polymer (A).

  Furthermore, the resin powder of the present invention preferably contains an acrylic block copolymer (A), an acrylic polymer (B), and a plasticizer (C).

  Furthermore, the resin powder of the present invention is preferably coated with a polymer latex.

<Acrylic block copolymer (A)>
The structure of the block copolymer (A) may be linear, branched (star), or a mixture thereof, and the required block copolymer (A). The linear block copolymer is preferable from the viewpoints of cost and ease of polymerization.

The arrangement of the linear block copolymer is not particularly limited. However, from the viewpoint of the physical properties or physical properties of the composition, a methacrylic polymer block (A) constituting the acrylic block copolymer (A) ( a) (hereinafter referred to as polymer block (a) or block (a)) and acrylic polymer block (b) (hereinafter referred to as polymer block (b) or block (b)) have the general formula: (Ab) _n , general formula: a- (ba) _n , general formula: (b-a) _n -b (n is an integer of 1 to 3) It is preferably at least one block copolymer selected. Among these, from the viewpoint of easy handling at the time of processing and physical properties in the case of a composition, an ab type diblock copolymer, an abb type triblock copolymer, or These mixtures are preferred.

  The number average molecular weight of the block copolymer (A) measured by gel permeation chromatography is not particularly limited, but is preferably 30,000 to 500,000, more preferably 30,000 to 200,000. If the number average molecular weight is small, the viscosity is low, and if the number average molecular weight is large, the viscosity tends to be high. Therefore, the viscosity is appropriately set according to the required processing characteristics.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography of the block copolymer is not particularly limited, but is preferably 1.8 or less, more preferably 1 .5 or less. When Mw / Mn exceeds 1.8, the homogeneity of the block copolymer tends to decrease.

  The composition ratio of the methacrylic polymer block (a) and the acrylic polymer block (b) of the block copolymer (A) is 5 to 90% by weight of the methacrylic polymer block (a), and the acrylic weight The combined block (b) is desirably 95 to 10% by weight. When the proportion of the methacrylic polymer block (a) is less than 5% by weight, the shape tends to be difficult to be maintained at the time of molding, and when the proportion of the acrylic polymer block (b) is less than 10% by weight, an elastomer is obtained. There is a tendency that the elasticity and the meltability at the time of molding are lowered. From the viewpoint of maintaining the shape during molding and elasticity as an elastomer, the composition ratio is 10 to 60% by weight of the methacrylic polymer block (a) and 90 to 40% by weight of the acrylic polymer block (b). The methacrylic polymer block (a) is preferably 15 to 50% by weight, and the acrylic polymer block (b) is more preferably 85 to 50% by weight.

  The hardness of the elastomer composition tends to be low when the proportion of the methacrylic polymer block (a) is small and high when the proportion of the methacrylic polymer block (a) is large. For this reason, the proportion of the methacrylic polymer block (a) may be appropriately set according to the required hardness. Further, the viscosity tends to be low when the proportion of the methacrylic polymer block (a) is small and high when the proportion of the methacrylic polymer block (a) is large. For this reason, the proportion of the methacrylic polymer block (a) may be appropriately set according to required processing characteristics.

The relationship between the glass transition temperatures of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the acrylic block copolymer (A) is the glass transition of the methacrylic polymer block (a). Assuming that the temperature is Tg _a and the glass transition temperature of the acrylic polymer block (b) is Tg _b , the relationship of the following formula is preferably satisfied in terms of mechanical strength, rubber elasticity, and the like.
Tg _a > Tg _b

The glass transition temperature (Tg) of the polymer (methacrylic polymer block (a) and acrylic polymer block (b)) is set according to the following Fox formula: This can be done by setting the ratio.
_{1 / Tg = (W 1 /} Tg 1) + (W 2 / Tg 2) + ... + (W m / Tg m)
W ₁ + W ₂ + ... + W _m = 1
(Wherein Tg represents the glass transition temperature of the polymer portion, and Tg ₁ , Tg ₂ ,..., Tg _m represent the glass transition temperatures of the respective polymerization monomers. Also, W ₁ , W ₂ ,. _m represents the weight ratio of each polymerization monomer.)

  As the glass transition temperature of each polymerization monomer in the Fox formula, for example, a value described in Polymer Handbook Third Edition (Wiley-Interscience 1989) may be used.

  The glass transition temperature can be measured by DSC (differential scanning calorimetry) or tan δ peak of dynamic viscoelasticity, but the methacrylic polymer block (a) and the acrylic polymer block (b). If the polarity is too close or the number of block monomer chains is too small, the measured values may deviate from the calculation formula based on the Fox equation.

<Methacrylic polymer block (a)>
The methacrylic polymer block (a) is a block obtained by polymerizing a monomer having a methacrylic acid ester as a main component. From the viewpoint of processability, the methacrylic acid ester is 50 to 100% by weight and It is preferable that it consists of 0-50 weight% of vinyl-type monomers copolymerizable with.

  Examples of the methacrylic acid ester constituting the methacrylic polymer block (a) include, for example, methyl methacrylate, ethyl methacrylate, methacrylate-n-propyl, isopropyl methacrylate, and methacrylate-n-. Butyl, isobutyl methacrylate, methacrylate-n-pentyl, methacrylate-n-hexyl, cyclohexyl methacrylate, methacrylate-n-heptyl, methacrylate-n-octyl, methacrylate-2- Ethylhexyl, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, phenyl methacrylate, toluyl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methacrylate 3-methoxybutyl 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, stearyl methacrylate, glycidyl methacrylate, 2-aminoethyl methacrylate, γ- (methacryloyloxypropyl) trimethoxysilane, γ- (Methacryloyloxypropyl) dimethoxymethylsilane, ethylene oxide adduct of methacrylic acid, trifluoromethylmethyl methacrylate, methacrylic acid-2-trifluoromethylethyl, methacrylic acid-2-perfluoroethylethyl, methacrylic Acid-2-perfluoroethyl-2-perfluorobutylethyl, methacrylic acid-2-perfluoroethyl, perfluoromethyl methacrylate, diperfluoromethylmethyl methacrylate, -2-acrylic methacrylate Oromechiru 2-perfluoroethyl methyl, methacrylic acid-2-perfluorohexylethyl, methacrylic acid-2-perfluorodecyl ethyl, and the like methacrylic acid-2-perfluoroalkyl-hexadecyl ethyl.

  These can be used alone or in combination of two or more. Among these, methyl methacrylate is preferable in terms of processability, cost, and availability. Further, the glass transition point can be increased by copolymerizing isobornyl methacrylate and cyclohexyl methacrylate. Furthermore, methacrylic acid-t-butyl is preferable as a precursor for introducing an acid anhydride to improve heat resistance.

  Examples of vinyl monomers copolymerizable with the methacrylic acid ester constituting the methacrylic polymer block (a) include acrylic acid esters, aromatic alkenyl compounds, conjugated diene compounds, and halogen-containing unsaturated compounds. And silicon-containing unsaturated compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, maleimide compounds, and the like.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, acrylic acid-n-propyl, isopropyl acrylate, acrylic acid-n-butyl, acrylic acid isobutyl, acrylic acid-t-butyl, and acrylic acid-n-. Pentyl, acrylate-n-hexyl, cyclohexyl acrylate, acrylate-n-heptyl, acrylate-n-octyl, acrylate-2-ethylhexyl, nonyl acrylate, decyl acrylate, dodecyl acrylate, phenyl acrylate, Toluyl acrylate, benzyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, stearyl acrylate, acrylic acid Guri Ziryl, 2-aminoethyl acrylate, ethylene oxide adduct of acrylic acid, trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, 2-perfluoroethyl ethyl acrylate, 2-acrylic acid-2- Perfluoroethyl-2-perfluorobutylethyl, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl acrylate, acrylic Examples include acid-2-perfluorohexylethyl, 2-perfluorodecylethyl acrylate, and 2-perfluorohexadecylethyl acrylate.

  Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Examples of the conjugated diene compound include butadiene and isoprene. Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride. Examples of the silicon-containing unsaturated compound include vinyltrimethoxysilane and vinyltriethoxysilane. Examples of the unsaturated dicarboxylic acid compound include maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid, fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid, and the like. Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like. Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

  These can be used alone or in combination of two or more. These vinyl monomers are appropriately selected from the viewpoints of adjusting the glass transition temperature required for the methacrylic polymer block (a) and compatibility with the acrylic polymer block (b). .

  The methacrylic polymer block (a) is preferably designed to have a glass transition temperature of 25 to 130 ° C, and preferably 40 to 130 ° C, from the viewpoint of thermal deformation of the elastomer composition. More preferably, it is more preferably 50 to 130 ° C. When the glass transition temperature of (a) is lower than the temperature of the environment in which the elastomer composition is used, thermal deformation may easily occur due to a decrease in cohesive force.

  From the viewpoints described above, the methacrylic polymer block (a) is mainly composed of methyl methacrylate and for the purpose of controlling the glass transition point, ethyl acrylate, acrylic acid-n-butyl, acrylic acid. A block obtained by polymerizing at least one monomer selected from the group consisting of 2-methoxyethyl and 2-ethylhexyl acrylate is preferable.

<Acrylic polymer block (b)>
The acrylic polymer block (b) is a block formed by polymerizing a monomer having an acrylic ester as a main component. From the viewpoint of rubber elasticity and the like, the acrylic ester is 50 to 100% by weight and copolymerized therewith. It is preferably composed of 0 to 50% by weight of a possible vinyl monomer.

  Examples of the acrylic acid ester constituting the acrylic polymer block (b) include the same monomers as the acrylic acid ester exemplified as the monomer constituting the methacrylic polymer block (b). it can.

  These may be used alone or in combination of two or more. Among these, acrylic acid-n-butyl is preferable from the viewpoint of rubber elasticity, low temperature characteristics and cost balance. Furthermore, when low temperature characteristics, mechanical characteristics, and compression set are required, 2-ethylhexyl acrylate may be copolymerized. If oil resistance and mechanical properties are required, ethyl acrylate is preferred. Further, when it is necessary to impart low temperature characteristics and oil resistance and to improve the surface tackiness of the resin, 2-methoxyethyl acrylate is preferable. When a balance between oil resistance and low-temperature characteristics is required, a combination of ethyl acrylate, acrylic acid-n-butyl and acrylic acid-2-methoxyethyl is preferred. Furthermore, when introducing an acid anhydride group in order to improve heat resistance, the precursor is preferably tert-butyl acrylate.

  Examples of vinyl monomers copolymerizable with the acrylic ester constituting the acrylic polymer block (b) include methacrylic ester, aromatic alkenyl compound, vinyl cyanide compound, conjugated diene compound, halogen, and the like. Examples thereof include an unsaturated compound containing silicon, an unsaturated compound containing silicon, an unsaturated dicarboxylic acid compound, a vinyl ester compound, and a maleimide compound.

  Methacrylic acid ester, aromatic alkenyl compound, vinyl cyanide compound, conjugated diene compound, halogen-containing unsaturated compound, silicon-containing unsaturated compound, unsaturated dicarboxylic acid compound, vinyl ester compound, maleimide compound The monomer similar to what was illustrated as a monomer which comprises a system polymer block (a) can be mention | raise | lifted.

  These can be used alone or in combination of two or more. These vinyl monomers are appropriately selected in consideration of the balance of the glass transition temperature and oil resistance required for the acrylic polymer block (b), compatibility with the methacrylic polymer block (a), and the like. Choose the preferred one.

  The acrylic polymer block (b) preferably has a glass transition temperature of 25 ° C. or lower, more preferably 0 ° C. or lower, and further preferably −20 ° C., from the viewpoint of rubber elasticity of the elastomer composition. It is as follows. If the glass transition temperature of the acrylic polymer block (b) is lower than the temperature of the environment in which the elastomer composition is used, rubber elasticity is easily developed.

  From the viewpoints described above, the acrylic polymer block (b) is at least one selected from the group consisting of -n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate. In addition, a block obtained by polymerizing 50 to 100% by weight of different acrylates copolymerizable with these and 50 to 0% by weight of vinyl monomers copolymerizable with these is preferable.

  From the viewpoint of rubber elasticity of the elastomer composition, the glass transition temperature of the acrylic polymer block (b) is preferably 25 ° C. or less, more preferably 0 ° C. or less, and further preferably −20 ° C. or less. When the glass transition temperature of the acrylic polymer block (b) is higher than the temperature of the environment in which the elastomer composition is used, flexibility and rubber elasticity are hardly exhibited.

  From the viewpoints described above, the acrylic polymer block (b) comprises an acid anhydride group, a carboxyl group or an acid anhydride group, a monomer having a carboxyl group precursor, and acrylic acid-n-butyl, acrylic acid. A block obtained by polymerizing a monomer having at least one selected from the group consisting of ethyl and 2-methoxyethyl acrylate as a main component is preferable.

The Tg _b of the acrylic polymer block (b) can be set by setting the weight ratio of the monomers in each polymer portion according to the Fox formula.

<Acid anhydride group and carboxyl group>
The acid anhydride group and carboxyl group are methacrylic polymer block (a) and / or acrylic group for imparting chemical resistance and rubber elasticity to the obtained molded product and maintaining mechanical properties at high temperature. One or more per block copolymer molecule is preferably introduced into the polymer block (b). An acid anhydride group and a carboxyl group are the reactivity of an acrylic block copolymer (A) and an acrylic polymer (B), a methacrylic polymer block (a), and an acrylic polymer block (b). Either an acid anhydride group or a carboxyl group may be introduced depending on the cohesive strength and glass transition temperature of the acrylic block copolymer, the required physical properties of the acrylic block copolymer (A), ease of introduction, etc. It is good or may be introduced together.

  In the present invention, the acid anhydride group and the carboxyl group may act as a reaction point with the acrylic polymer (B), and as a reaction point or a crosslinking point for the block copolymer to have a high molecular weight or to be crosslinked. It is preferable to act. The acid anhydride group and the carboxyl group are introduced into the block copolymer in a form in which the acid anhydride group and the carboxyl group are protected with an appropriate protecting group, or in the form of a precursor of the acid anhydride group and the carboxyl group. Later, it can be introduced by generating an acid anhydride group and a carboxyl group by a known chemical reaction.

  The content of the acid anhydride group and the carboxyl group is the cohesive force of the acid anhydride group and the carboxyl group, the reactivity, the structure and composition of the acrylic block copolymer (A), and the acrylic block copolymer (A). The number of blocks constituting the glass transition temperature varies depending on the necessity, and the number needs to be appropriately set as necessary. Preferably, the average number per block copolymer is 1.0 or more, more preferably 2.0 or more. This is because when the number is less than 1.0, there is a tendency that the high molecular weight due to the bimolecular reaction of the block copolymer and the heat resistance improvement due to crosslinking tend to be insufficient.

Note that when improved cohesive force and glass transition temperature Tg _b of the acrylic polymer block (b) by introducing an acid anhydride group or a carboxyl group, there is a tendency that flexibility, rubber elasticity, low temperature characteristics deteriorate. For this reason, when an acid anhydride group and / or a carboxyl group are introduced into the acrylic polymer block (b), the acrylic block copolymer (A) is introduced in a range that does not deteriorate the flexibility, rubber elasticity, and low temperature characteristics. It is preferable to do. Specifically, it is preferably introduced such that the glass transition temperature Tg _b of the acrylic polymer block (b) after introduction of the acid anhydride group or carboxyl group is 25 ° C. or less, more preferably 0 ° C. or less, More preferably, the temperature is set to −20 ° C. or lower.

  Below, an acid anhydride group and a carboxyl group are demonstrated.

<Acid anhydride group>
When the composition contains a compound having active protons, the acid anhydride groups in the methacrylic polymer block (a) and the acrylic polymer block (b) are heated at a predetermined temperature described below. By this, it reacts easily with the reactive functional group (D) in the compound (B). The introduction position of the acid anhydride group is not particularly limited, and the acid anhydride group is introduced into the main chain in the methacrylic polymer block (a) and the acrylic polymer block (b). It may be introduced to the side chain. The acid anhydride group is an anhydride of a carboxyl group, and is introduced into the main chain for ease of introduction into the methacrylic polymer block (a) and the acrylic polymer block (b). Is specifically represented by the general formula (1). General formula (1):

(Wherein R ¹ is hydrogen or a methyl group, two R ^{1 s} may be the same or different from each other, n is an integer of 0 to 3, and m is an integer of 0 or 1) Is done.

  N in General formula (1) is an integer of 0-3, Preferably it is 0 or 1, More preferably, it is 1. When n is 4 or more, polymerization tends to be complicated, and cyclization of the acid anhydride group tends to be difficult.

  As a method for introducing the acid anhydride group, it is preferable that the acid anhydride group is introduced into the acrylic block copolymer in the form of a precursor of the acid anhydride group and then cyclized. In particular, the general formula (2):

(Wherein R ² represents hydrogen or a methyl group; R ³ represents hydrogen, a methyl group or a phenyl group; at least two of the three R ³ are selected from a methyl group and / or a phenyl group; R ³ may be the same or different from each other. It is preferable to melt-knead an acrylic block copolymer having at least one unit represented by

  The introduction of the unit represented by the general formula (2) into the acrylic polymer block (b) is obtained by copolymerizing an acrylate or methacrylic acid ester monomer derived from the general formula (2). Can be done. Examples of the monomer include t-butyl (meth) acrylate, isopropyl (meth) acrylate, α, α-dimethylbenzyl (meth) acrylate, α-methylbenzyl (meth) acrylate, It is not limited to these. Among these, (meth) acrylic acid-t-butyl is preferable from the standpoints of availability, ease of polymerization, and ease of acid anhydride group formation. In the present application, (meth) acrylic acid means acrylic acid or methacrylic acid.

  The formation of the acid anhydride group is preferably performed by heating the acrylic block copolymer having a precursor of the acid anhydride group at a high temperature, and more preferably by heating at 180 to 300 ° C. . When the temperature is lower than 180 ° C., the acid anhydride group is likely to be insufficiently generated. When the temperature is higher than 300 ° C., the acrylic block copolymer itself having a precursor of the acid anhydride group may be decomposed.

<Carboxyl group>
The carboxyl group in the acrylic block copolymer (A) easily reacts with the reactive functional group (D) in the compound (B). The introduction position of the carboxyl group is not particularly limited, and the carboxyl group may be introduced into the main chain in the methacrylic polymer block (a) and the acrylic polymer block (b). Although it may be introduced into the side chain, it is preferably introduced into the main chain from the viewpoint of ease of introduction.

  When the monomer having a carboxyl group does not poison the catalyst under the polymerization conditions, the introduction of the carboxyl group is preferably carried out by introducing it directly by polymerization. When the catalyst is deactivated during the polymerization, it is preferably carried out by a method of introducing a carboxyl group by functional group conversion.

  As a method for introducing a carboxyl group by functional group conversion, the carboxyl group is introduced into an acrylic block copolymer in the form of protecting the carboxyl group with an appropriate protecting group or in the form of a functional group that is a precursor of the carboxyl group. A method of generating a functional group by a predetermined chemical reaction known later is mentioned.

  As a synthesis method of the acrylic block copolymer (A) having a carboxyl group, for example, a functional group that becomes a precursor of a carboxyl group, such as t-butyl (meth) acrylate, trimethylsilyl (meth) acrylate, and the like. A method of synthesizing an acrylic block copolymer containing a monomer having a carboxyl group and generating a carboxyl group by a known chemical reaction such as hydrolysis or acid decomposition (Japanese Patent Laid-Open Nos. 10-298248 and 2001-234146) ) And general formula (2):

(Wherein R ² represents hydrogen or a methyl group; R ³ represents hydrogen, a methyl group or a phenyl group; at least two of the three R ³ are selected from a methyl group and / or a phenyl group; R ³ may be the same or different from each other.) There is a method of introducing an acrylic block copolymer having at least one unit represented by melt kneading.

  Moreover, a carboxyl group can also be introduce | transduced by hydrolyzing the said acid anhydride group.

<Method for producing acrylic block copolymer (A)>
A method for producing the acrylic block copolymer (A) is not particularly limited, but a controlled polymerization method using an initiator is preferably used. Examples of the controlled polymerization method include a living anion polymerization method, a radical polymerization method using a chain transfer agent, and a recently developed living radical polymerization method. Especially, it is preferable to manufacture by the living radical polymerization method from the point of control of the molecular weight and structure of an acryl-type block copolymer.

  The living radical polymerization method is a radical polymerization method in which the activity at the polymerization terminal is maintained without being lost. In the narrow sense, living polymerization refers to polymerization in which the terminal always has activity, but generally includes pseudo-living polymerization in which the terminal is inactivated and the terminal is in equilibrium. . The definition here is also the latter.

  As the living radical polymerization method, a method using a chain transfer agent such as polysulfide, cobalt porphyrin complex (J. Am. Chem. Soc., 1994, 116, 7943). ) And nitroxide compounds (Macromolecules, 1994, 27, 7228), atom transfer radicals using organic halides as initiators and transition metal complexes as catalysts Examples thereof include a polymerization method (Atom Transfer Radical Polymerization: ATRP). In the present invention, there is no particular limitation as to which of these methods is used, but from the viewpoint of ease of control, etc., a method using the atom transfer radical polymerization method described in International Publication No. 2004/13192 pamphlet or the like Is preferred.

<Acrylic polymer (B)>
The acrylic polymer (B) of the present invention needs to have 1.1 or more reactive functional groups (D) in one molecule. The acrylic polymer (B) improves molding fluidity as a plasticizer during molding of the composition, and at the same time, reacts with an acid anhydride group or carboxyl group in the acrylic block copolymer (A) during molding. It reacts with the group (D) and plays a role of increasing the molecular weight or crosslinking of the acrylic block copolymer (A). In addition, the number of reactive functional groups (D) here represents the average number of reactive functional groups (D) present in one molecule of the acrylic polymer (B).

  The number of reactive functional groups (D) in the acrylic polymer (B) needs to be 1.1 or more, preferably 1.5 or more, and more preferably 2.0 or more. The number is the reactivity of the reactive functional group (D), the site and mode of the reactive functional group (D), the acid anhydride group and / or the carboxyl group in the acrylic block copolymer (A). Vary depending on the number, location, and mode of the contained. When the content of the reactive functional group (D) is less than 1.1, the effect of the block copolymer as a high molecular weight reaction agent or a crosslinking agent is reduced, and the heat resistance of the acrylic block copolymer (A) is reduced. The effect of improving the property may be insufficient.

  The acrylic polymer (B) is obtained by polymerizing one or more acrylic monomers, or one or two or more acrylic monomers and a monomer other than the acrylic monomer. It is preferable that it is obtained by polymerizing.

  Examples of the acrylic monomer include acrylic acid esters and methacrylic acid esters described in the section of the methacrylic polymer block (a). Among these, it is preferable from the point of availability to use either acrylic acid-n-butyl, ethyl acrylate and -2-methoxyethyl acrylate, or a combination of two or more thereof.

  The monomer other than the acrylic monomer is not particularly limited as long as it is a monomer copolymerizable with the acrylic monomer, and for example, vinyl acetate, styrene and the like can be used.

  In addition, it is preferable that the ratio of the monomer component which has an acryloyl group with respect to all the monomer components which comprise an acryl-type polymer (B) is 70 weight% or more. When the proportion is less than 70% by weight, the weather resistance is lowered and the compatibility with the acrylic block copolymer (A) tends to be lowered. Moreover, discoloration tends to occur in the molded product.

  The molecular weight of the acrylic polymer (B) is not particularly limited, but is preferably a low molecular weight having a weight average molecular weight of 30,000 or less, more preferably 500 to 30,000, and more preferably 500 to 10,000. Those are particularly preferred. When the weight average molecular weight is less than 500, the molded product tends to be sticky. On the other hand, when the weight average molecular weight exceeds 30,000, plasticization of the molded product tends to be insufficient.

  The viscosity of the acrylic polymer (B) is preferably 35,000 mPa · s or less when measured with a cone-plate type rotational viscometer (E-type viscometer) at 25 ° C., and 10,000 mPa · s. More preferably, it is 5,000 mPa · s or less. When the viscosity is higher than 35,000 mPa · s, the plasticizing effect of the composition tends to decrease. Although there is no particular lower limit of the preferred viscosity, the normal viscosity of the acrylic polymer is 10 mPa · s or more.

  The glass transition temperature Tg of the acrylic polymer (B) is preferably 100 ° C. or less, more preferably 25 ° C. or less, and more preferably 0 ° C. or less when measured by differential scanning calorimetry (DSC). More preferably, it is particularly preferably -30 ° C or lower. When glass transition temperature Tg exceeds 100 degreeC, there exists a tendency for the effect which improves a moldability as a plasticizer to become inadequate, and it exists in the tendency for the softness | flexibility of the molded object obtained to fall.

  The acrylic polymer (B) can be obtained by polymerizing by a conventionally known method. The polymerization method may be appropriately selected as necessary. For example, suspension polymerization method, emulsion polymerization method, bulk polymerization method, living anion polymerization method, polymerization using chain transfer agent, and control polymerization method such as living radical polymerization method, etc. However, it is preferable to use a controlled polymerization method in which a polymer having good weather resistance and heat resistance and having a relatively low molecular weight and a small molecular weight distribution is obtained, and it is costly to use the high-temperature continuous polymerization method described below. It is more preferable in terms of surface.

  The acrylic polymer (B) is preferably obtained by a polymerization reaction at a temperature of 180 to 350 ° C. At this polymerization temperature, an acrylic polymer having a relatively low molecular weight can be obtained without using a polymerization initiator or a chain transfer agent. For this reason, the acrylic polymer is an excellent plasticizer and has good weather resistance. Specifically, the high-temperature continuous polymerization method described in JP-T-57-502171, JP-A-59-6207, JP-A-60-215007 and WO 01/083619, An example is a method in which a mixture of the above monomers is continuously supplied into a reactor set at a predetermined temperature and pressure at a constant supply rate, and an amount of the reaction liquid corresponding to the supply amount is withdrawn.

<Reactive functional group (D)>
Examples of the reactive functional group (D) include an epoxy group, a hydroxyl group, and an amino group, and it is desirable to use at least one functional group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and an amino group. Among these functional groups, from the reactivity with the acid anhydride group and carboxyl group contained in the acrylic block copolymer (A) and the ease of introduction of the functional group into the acrylic polymer (B), An epoxy group is more preferable.

  Introduction of the reactive functional group (D) into the acrylic polymer (B) is, for example, a vinyl monomer having a reactive functional group (D) copolymerizable with the monomer constituting the acrylic polymer. It can be carried out by copolymerizing the body.

  Specific examples of the acrylic polymer (B) having a reactive functional group (D) include ARUFON (registered trademark) XG4000, ARUFON UG4000, ARUFON XG4010, ARUFON UG4010, ARUFON UG4012, ARUFON XD945 of Toagosei Co., Ltd. ARUFON XD950, ARUFON UG4030, ARUFON UG4070, etc. can be used preferably. These are acrylic polymers such as all acrylic and acrylate / styrene, and are polymers containing 1.1 or more epoxy groups in one molecule.

<Resin powder>
The resin powder of the present invention comprises an acrylic block copolymer (A) having an acid anhydride group and / or a carboxyl group, and an acrylic polymer (B) having an average of 1.1 or more epoxy groups per molecule. An acrylic polymer powder made of

  The proportion of the blend amount of the acrylic block copolymer (A) and the acrylic polymer (B) contained in the acrylic polymer powder is not particularly limited, but the blend amount of the acrylic polymer (B) is: 0.1-100 weight part is preferable with respect to 100 weight part of acrylic block copolymers (A), and 1-50 weight part is more preferable. When the blending amount of the acrylic polymer (B) is less than 0.1 parts by weight, the crosslinking reaction with the acrylic block copolymer (A) does not proceed sufficiently, and the heat resistance of the molded product becomes insufficient. If the amount is more than 100 parts by weight, the crosslinking reaction may proceed excessively, and the elongation and flexibility of the molded product may be impaired.

  The acrylic polymer powder has a low melt viscosity during molding and excellent moldability (thermal meltability). On the other hand, an acrylic acid group and a carboxyl group in the block copolymer (A) during heating and acrylic It is preferable that the reactive functional group (D) in the polymer (B) reacts to increase the molecular weight or crosslink the acrylic block copolymer (A). In terms of improving heat resistance, crosslinking is more preferable.

  The acrylic polymer powder preferably further contains a plasticizer (C). Although there is no restriction | limiting in particular as a plasticizer (C), It is preferable that it is a plasticizer which consists of a trimellitic acid ester type compound and / or a pyromellitic acid ester type compound. The addition amount of the plasticizer is not particularly limited, but is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the acrylic block copolymer (A).

  In order to accelerate the reaction during molding, a catalyst may be added to the acrylic polymer powder as necessary. For example, curing agents commonly used for epoxy resins such as acid anhydrides such as acid dianhydrides, amines, and imidazoles, and metal compounds such as zinc tert-butylbenzoate, zinc laurate, and zinc oxide Can be used. Among these, an inorganic zinc compound which is a metal compound is preferable.

  In addition, the acrylic polymer powder according to the present invention may contain a filler, a lubricant, a stabilizer, a flexibility imparting agent, a flame retardant, a pigment, an antistatic agent, an antibacterial antifungal agent, etc. You may mix | blend.

<Method for producing acrylic polymer powder>
The method for producing the acrylic polymer powder used in the present invention is not particularly limited. For example, a block or pellet-shaped acrylic polymer powder composition is pulverized by a freeze pulverization method or a room temperature pulverization method. There is a method for obtaining an acrylic polymer powder.

  Moreover, when obtaining acrylic polymer powder, it is not always necessary to go through a pulverization step. For example, when an acrylic polymer powder composition is obtained with a continuous extruder, an acrylic polymer composition that can be used for powder slush molding can be directly obtained as a micropellet by attaching a special die. it can. In addition, after dissolving the acrylic polymer (B) in an acrylic block copolymer solution in which the acrylic block copolymer (A) is made into beads slurry by a suspension method and melted in an organic solvent, water and Mix and stir to form droplets of acrylic block copolymer solution of a predetermined size, and heat as it is to evaporate the organic solvent to obtain a powder with an appropriate particle size distribution . At this time, the acrylic block copolymer solution is preliminarily added with the above-mentioned crosslinking promoting additive, catalyst, filler, lubricant, stabilizer, plasticizer, flexibility imparting agent, flame retardant, pigment, antistatic agent, antibacterial agent. An anti-fungal agent, etc. may be dissolved and dispersed. Moreover, in order to stably obtain droplets of a predetermined size, polyvinyl alcohol, polyvinyl alcohol / polyvinyl acetate copolymer, methyl cellulose or the like may be added as an emulsifier.

  The powder obtained as a result is preferably fractionated only with a particle size of 100 to 500 μm using a sieve or the like, and most preferably with a particle size of 150 to 300 μm. Powder containing particles having a particle size smaller than 100 μm is a cause of promoting aggregation of powders, and the handling property is lowered and the powder fluidity is deteriorated. For this reason, when used for powder slush molding, the powder does not sufficiently reach the end of the mold, and the design of the molded article is impaired. In addition, when a powder containing particles having a particle size larger than 500 μm is used for powder slush molding, the powder having a large particle size is not sufficiently melted, so that the design of the molded product is impaired.

<Polymer latex>
The resin powder of the present invention is preferably coated with a polymer latex. The polymer latex is preferably an acrylic polymer latex obtained by emulsion polymerization. As the acrylic polymer latex, those having a resin composition similar to that of the acrylic polymer powder are preferable because they are excellent in quality as particles. For example, an acrylic ester and a methacrylic ester are homopolymerized or a mixture of a plurality of types is used. Examples thereof include latex obtained by polymerization. For example, as a monomer to be used, alkyl acrylates having an alkyl group having 10 or less carbon atoms such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. Alkyl methacrylates having an alkyl group with 10 or less carbon atoms; allyl methacrylate, diallyl phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, glycidyl methacrylate, etc. In terms of availability and cost, acrylic acid esters and Butyl acrylate Te, methyl methacrylate is preferably a methacrylic acid ester. In 100 parts by weight of the polymer constituting the acrylic polymer latex, 85 to 99 parts by weight of methyl methacrylate, 1 to 15 parts by weight of butyl acrylate are preferable, 91 to 95 parts by weight of methyl methacrylate, and 5 parts of butyl acrylate. More preferred is ˜9 parts by weight.

  The molecular weight of the polymer constituting the acrylic polymer latex needs to be set in the range of 40,000 to 100,000 in terms of weight average molecular weight. When the molecular weight is less than 40,000, there is a problem in that the amount of the chain transfer agent having a strong malodor used for adjusting the molecular weight is increased and the odor of the molded article is increased. When the molecular weight is more than 100,000, there is a problem that the meltability is deteriorated when powder slush molding is performed at a low temperature, and the mechanical properties are deteriorated. In the present invention, the glass transition temperature of the polymer constituting the acrylic polymer latex needs to be 75 ° C. or higher. When the glass transition temperature is lower than 75 ° C., there is a problem that powder storage stability (blocking property) in an environment of 50 ° C. is deteriorated and latex is aggregated when the temperature is increased by heat treatment during granulation. Furthermore, it is necessary to set the particle diameter of the latex in emulsion polymerization to 500 to 800 mm. When the particle diameter of the latex is smaller than 500 mm, it is necessary to increase the amount of the emulsifier necessary for adjusting the particle diameter, thereby causing the problem of destabilizing the latex. When the particle diameter is larger than 800 mm, the number of latex particles is decreased, the coverage of the acrylic polymer powder is decreased, and the powder storage stability (blocking property) is deteriorated. Furthermore, when the coverage ratio is increased, that is, when the number of added latex parts is increased in order to improve the blocking property, there is a problem that the meltability of powder slush molding at low temperatures and the scratch property of the molded article are deteriorated.

  A general method for producing the above acrylic polymer latex is described in detail, for example, in JP-A-8-134316 and JP-A-8-217817.

  In order to obtain the weight average molecular weight by the emulsion polymerization method, a chain transfer agent is preferably used as a polymerization regulator. As the chain transfer agent species, those conventionally used for emulsion polymerization can be used, for example, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, 2-mercapto. Sulfur-containing chain transfer agents such as ethanol; halogen-containing chain transfer agents such as trichlorobromomethane, carbon tetrachloride and bromoform; nitrogen-containing chain transfer agents such as N, N-dimethylformamide and pivalonitrile; Other examples include terbinolene, mill cell, limonene, α-pinene, β-pinene and the like. Of these, β-mercaptopropionic acid-based chain transfer agents and thioglycolic acid-based chain transfer agents are preferable in terms of odor and chain transfer effect, and thioglycolic acid-based compounds such as 2-ethylhexyl thioglycolate are available. Further preferred from the point.

  A preferable amount of the chain transfer agent used in the emulsion polymerization is preferably 1 part by weight or less with respect to 100 parts by weight of the total monomers from the viewpoint of odor. Examples of the polymerization initiator used for emulsion polymerization include redox compounds and persulfate compounds, but persulfate compounds that do not use a reducing agent are preferable from the viewpoint of odor, and potassium persulfate is more preferable from the viewpoint of availability. .

  The preferred amount of potassium persulfate used in the emulsion polymerization is preferably 0.1 to 1 part by weight with respect to 100 parts by weight of all monomers from the viewpoint of latex stability during polymerization.

  The emulsifier that can be used in the emulsion polymerization is not particularly limited and includes an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric emulsifier. Among these, storage stability, polymerization stability, An anionic emulsifier is preferred from the viewpoint of coagulation stability. Moreover, an emulsifier may be used independently or can also be used in combination of multiple types.

  Examples of the anionic emulsifier include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate esters such as sodium lauryl sulfate; Polyoxyethylene alkyl ether sulfate salts such as sodium ethylene lauryl ether sulfate; for example, polyoxyethylene alkyl aryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate; sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, poly Illustrate alkyl sulfosuccinic acid ester salts such as sodium oxyethylene lauryl sulfosuccinate, alkane sulfonates and their derivatives Bets can be, these emulsifiers can be used singly or in combination of well or two or more be used. Of these, alkane sulfonates excellent in heat resistance are preferable, and sodium alkane sulfonate is more preferable from the viewpoint of availability.

  The amount of the preferred emulsifier used in the emulsion polymerization is preferably 0.3 to 1.5 parts by weight with respect to 100 parts by weight of all monomers from the viewpoint of latex particle diameter, latex stability during and after polymerization. .

  The polymerization temperature during emulsion polymerization is not particularly limited, but is preferably 50 to 90 ° C. from the viewpoint of polymerization productivity and latex stability during polymerization.

  The acrylic polymer latex is preferably obtained by an emulsion polymerization method using a thioglycolic acid compound as a chain transfer agent, a persulfuric acid compound as a polymerization initiator, and an anionic surfactant as an emulsifier.

<Spherical inorganic particles>
The acrylic polymer powder is preferably formed by adhering spherical inorganic particles. By adhering the spherical inorganic particles, the powder fluidity and blocking resistance can be improved without reducing the heat melting property.

  Here, the term “spherical” refers to particles having a circularity of 0.7 or more. Here, the circularity refers to a value obtained by calculating a ratio of each of a plurality of particles (the projected area of particles / the area of a circle having the maximum particle length as a diameter) and arithmetically averaging them. For this reason, when the particle is a true sphere, the value of the circularity generally converges to 1, and the value tends to decrease as the particle deviates from the true sphere. The circularity is an average of about 10 measurement particles. If the circularity is less than 0.7, sufficient powder flowability and blocking resistance improving effects tend not to be obtained. The circularity of the spherical inorganic particles of the present invention is preferably 0.8 or more, and more preferably 0.9 or more.

  The amount of the spherical inorganic particles is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, and 0.1 to 1 part by weight with respect to 100 parts by weight of the acrylic polymer powder. It is more preferable that it is 0.1-0.5 weight part. When the amount is less than 0.01 part by weight, the effect of improving the powder fluidity and blocking resistance may be insufficient, and when the amount is more than 5 parts by weight, the heat melting property may be insufficient.

  The average particle diameter of the spherical inorganic particles is not particularly limited, but is preferably in the range of 0.01 μm to 50 μm, more preferably in the range of 0.1 μm to 30 μm, and 0.1 μm to 10 μm. More preferably, it is 1 μm to 10 μm. If it is smaller than 0.01 μm, the effect of improving the blocking resistance tends to be insufficient, and if it is larger than 50 μm, the scratch resistance of the molded product tends to deteriorate. The average particle diameter of the spherical inorganic particles is usually a value measured by a laser method.

  The spherical inorganic particles are not particularly limited as long as they are inorganic compounds. For example, carbon allotropes such as carbon black, metal oxides such as silica, alumina, cerium oxide, titanium oxide, and calcium carbonate, metals such as silicon nitride and aluminum nitride Examples thereof include materials generally used for inorganic fillers such as nitride, talc and kaolin. Among these, silica and alumina are preferable from the viewpoint of cost and availability.

  The spherical inorganic particles are not particularly limited as long as the appearance is spherical, and may be homogeneous inside, porous, or hollow. Among these, silica gel having a porous interior is preferable from the viewpoint of cost and availability.

  The pore volume of the spherical inorganic particles is not particularly limited, but is preferably 1.00 ml / g or more, more preferably 1.30 ml / g or more, and 1.45 ml / g or more. More preferably, it is particularly preferably 1.50 ml / g or more. If it is less than 1.00 ml / g, the amount of addition necessary for obtaining sufficient blocking resistance increases, and the scratch resistance may decrease.

  The pore volume is calculated from the following formula based on the amount of water that is charged into a jar with a predetermined amount of spherical inorganic particles and water is added to the jar and the spherical inorganic particles become a gel and does not fall even if the bottle is inverted. Ask for.

Pore volume (ml / g) = amount of water added (ml) / spherical inorganic particles (g)
Specific product names of the spherical inorganic particles include Cyrossphere C-1504 (manufactured by Fuji Silysia Chemical Co., Ltd.), Cyrossphere C-1510 (manufactured by Fuji Silysia Chemical Co., Ltd.), and the like. However, it is not limited to these.

<Pigment>
It is preferable that a powder pigment adheres to the acrylic polymer powder. The light resistance can be improved by attaching a powder pigment.

  It does not specifically limit as a powder pigment, A well-known organic pigment and / or an inorganic pigment can be used. Examples of organic pigments include insoluble azo pigments, copper phthalocyanine pigments, quinacudrine pigments, and inorganic pigments include chromates, ferrocyan compounds, metal oxides (titanium oxide, zinc oxide, etc.), metal salts ( Sulfate, silicate, carbonate, phosphate, etc.), metal powder, carbon black and the like.

  The amount of powder pigment added to the acrylic polymer powder is usually 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer powder.

<Blend method>
The method of blending the spherical inorganic particles and the powder pigment into the acrylic polymer powder is not particularly limited, but a tumbler mixer is preferable.

  The temperature of the powder molding powder during mixing with the mixer is set to 60 ° C. or lower. When the temperature is higher than 60 ° C., the spherical inorganic particles of the anti-blocking agent are easily embedded in the acrylic polymer powder, and the acrylic polymer powder adheres in a stationary state during blending or storage. This will cause a blocking problem.

<Use and usage of molded body>
The molded body obtained by powder slush molding of the resin powder of the present invention can be suitably used as, for example, a skin material, a tactile material, and an appearance material. In addition, an abrasion resistant material, an oil resistant material, It can be used as a material having a purpose such as a vibration damping material or an adhesive material. As a shape, it can be used as a sheet, flat plate, film, small molded product, large molded product or other arbitrary shape, as a part such as panels, handles, grips, switches, etc. be able to. Although it does not restrict | limit especially as a use, The object for motor vehicles, household electrical appliances, or office electrical appliances are illustrated. For example, automotive skin materials, automotive tactile materials, automotive exterior materials, automotive panels, automotive handles, automotive grips, automotive switches, and household or office electrical panels Examples thereof include switches for household or office electrical appliances. Among these, it is suitably used for an automobile interior skin.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.

  In the examples, BA, MMA, TBA, and EA represent acrylate-n-butyl, methyl methacrylate, tert-butyl acrylate, and ethyl acrylate, respectively.

<Molecular weight measurement method>
The molecular weight shown in this example was measured by the GPC analyzer shown below, and the molecular weight in terms of polystyrene was determined using chloroform as the mobile phase. A Waters GPC system was used as the system, and Shodex K-804 (polystyrene gel) manufactured by Showa Denko KK was used as the column.

<Method for measuring conversion rate of polymerization reaction>
The conversion rate of the polymerization reaction shown in this example was measured using the following analyzer and conditions.
Equipment used: Gas chromatography GC-14B manufactured by Shimadzu Corporation
Sample preparation: The sample was diluted about 3 times with ethyl acetate, and butyl acetate was used as an internal standard.

<Formability test>
Powder slush molding:
The obtained powder was subjected to a molding melt test evaluation under the following conditions.
Equipment used: Metal plate with skin wrinkles (plate thickness 4.5mm, wrinkle depth 80%)
Heating conditions: 240 ° C
Heating time: The mold and powder are brought into contact at the first inversion, the mold is inverted after 6 seconds to separate the unmelted powder, the mold is removed after 1 minute, and the cooling start time is within 1 minute (water in the aquarium Cooling by touching)
Meltability evaluation index: The thickness of the molded product is uniform: ○, thickness unevenness in part: Δ, thickness unevenness in the whole, or pinholes: x

<Heat resistance test>
By molding, a sheet having an embossed surface with an initial glossiness of 1.0 to 2.0 under the following measurement conditions was produced. A 5 cm × 5 cm sample was cut out from the obtained sheet and left in an oven at 130 ° C. for 24 hours. The change in glossiness of the embossed surface was measured and evaluated according to the following criteria.
Equipment used: Gloss meter (Nippon Denshoku Industries Co., Ltd., VG-2000)
Incident angle: 60 °
Gloss change before and after test is less than +1;
Gloss change before and after test is +1 or more;

<Color unevenness evaluation>
A sheet was produced by molding. A sample of 5 cm × 5 cm was cut out from the obtained sheet, the color tone of the molded body was measured, and evaluated according to the following criteria.
Equipment used: Gloss meter (Nippon Denshoku Industries Co., Ltd. SE-2000)
Measurement mode: ΔE * is less than 0.5 for reflection mode specimens;
ΔE * is 0.5 or more for the standard; ×

<Measurement of volatile content>
Volatiles were carried out using the following measuring instrument.
A & D Co., Ltd. Heating and drying moisture meter MS-70 type heating temperature setting: 120 ° C., response speed: 0.005% / min, minimum display: 0.001%

(Production Example 1)
Synthesis of Acrylic Block Copolymer The following operation was performed to obtain an acrylic block copolymer. After replacing the inside of the pressure-resistant reactor with nitrogen, 0.89 parts by weight of copper bromide, 100 parts by weight of acrylate-n-butyl and 4.46 parts by weight of acrylate-t-butyl were charged, and stirring was started. Thereafter, a solution prepared by dissolving 1.24 parts by weight of diethyl 2,5-dibromoadipate in 9.18 parts by weight of acetonitrile (nitrogen bubbling) was charged as an initiator, and the temperature of the solution was increased to 75 ° C. Stir for minutes. When the solution temperature reached 75 ° C., 0.11 part by weight of pentamethyldiethylenetriamine was added as a ligand to initiate polymerization of the acrylic polymer block.

  The conversion rate of acrylic acid-n-butyl and acrylic acid-t-butyl was determined by gas chromatography analysis of the sampling solution at regular intervals from the initiation of polymerization. During polymerization, the polymerization rate was controlled by adding pentamethyldiethylenetriamine as needed. Pentamethyldiethylenetriamine was added twice in total (0.21 parts by weight in total) during the acrylic polymer block polymerization.

  When the conversion rate of acrylate-n-butyl was 99.0% and the conversion rate of tert-butyl acrylate was 99.1%, methyl methacrylate was 63.76 parts by weight, ethyl acrylate was 10.38% Part, 0.61 part by weight of copper chloride, 0.11 part by weight of pentamethyldiethylenetriamine and 137.41 parts by weight of toluene (nitrogen bubbled) were added to initiate polymerization of the methacrylic polymer block.

  Sampling was performed when methyl methacrylate and ethyl acrylate were added, and conversion rates of methyl methacrylate and ethyl acrylate were determined based on this sampling. After adding methyl methacrylate and ethyl acrylate, the internal temperature was set to 85 ° C. During polymerization, the polymerization rate was controlled by adding pentamethyldiethylenetriamine as needed. Pentamethyldiethylenetriamine was added a total of 6 times (0.64 parts by weight in total) during methacrylic polymer block polymerization. When the conversion rate of methyl methacrylate was 95.0%, 212.77 parts by weight of toluene was added, and the reactor was cooled to complete the reaction. When the GPC analysis of the obtained acrylic block copolymer was conducted, the number average molecular weight Mn was 72,100, and the molecular weight distribution Mw / Mn was 1.48.

  Toluene was added to the reaction solution containing the acrylic block copolymer to make the polymer concentration 25% by weight. 0.41 part by weight of p-toluenesulfonic acid was added to 100 parts by weight of this solution, and the inside of the reactor was purged with nitrogen, followed by stirring at 30 ° C. for 3 hours.

  The reaction solution was sampled to confirm that the solution was colorless and transparent, and 0.50 part by weight of Radiolite # 3000 manufactured by Showa Chemical Industry was added as a filter aid. Thereafter, the reactor was pressurized to 0.1 to 0.4 MPaG with nitrogen, and the solid content was separated using a pressure filter equipped with a polyester felt as a filter medium.

  After adding 0.15 parts by weight of Irganox 1010 as an antioxidant to 100 parts by weight of the block copolymer-containing solution after filtration, the inside of the reactor was purged with nitrogen and kept at 150 ° C. for 4 hours in a pressure-resistant reactor. Stir. After adding 1.75 parts by weight of Kyward 500SH as a solid base to the reaction solution cooled to 30 ° C., the inside of the reactor was purged with nitrogen and stirred for 2 hours. The reaction solution was sampled to confirm that the solution was neutral, and the reaction was completed. Thereafter, the reactor is pressurized to 0.1 to 0.4 MPaG with nitrogen, the solid content is separated using the pressure filter shown above equipped with polyester felt as a filter medium, and an acrylic block copolymer is contained. A polymer solution was obtained.

  The polymer solution was vacuum-dried at 80 ° C. to obtain an acrylic block copolymer. In addition, it was 101 degreeC when the glass transition temperature of the methacrylic polymer block (a) of the polymer 1 obtained by this manufacture example 1 was calculated according to the said Fox formula.

(Production Example 2)
Synthesis of Polymer Latex 200 parts of water, 0.16 part of sodium alkanesulfonate, and 0.25 part of potassium persulfate were charged into a reactor equipped with a stirring base, and the temperature was raised to 70 ° C. after purging with nitrogen. A mixed solution of 95 parts of methyl methacrylate, 5 parts of butyl acrylate and 0.65 part of 2-ethylhexyl thioglycolate was added over 6 hours, and 0.1893 parts of sodium alkanesulfonate was added 2 hours after the start of the addition. 0.2007 parts were added after hours. After completion of addition, 0.05 part of potassium persulfate was added and polymerization was carried out for 1 hour. Latex was obtained.

(Production Example 3)
Production of acrylic block copolymer composition powder: 200 parts by weight of pure water and 0.7 parts by weight of polyvinyl alcohol (trade name KH-17, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (3% aqueous solution) 23.3 parts by weight), 400 parts by weight of the polymer solution obtained in Production Example 1 (solid content concentration 25% by weight), ARUFON (registered trademark) UG4010 (Toagosei Co., Ltd.) which is an acrylic polymer having an epoxy group 10 parts by weight of RS800K which is a polyether ester plasticizer (manufactured by ADEKA), and extremely hardened oil of beef tallow which is an ester lubricant (melting point 60 ° C .: manufactured by Nippon Oil & Fats Co., Ltd.) 0.1 parts by weight, 0.3 parts by weight of a black powder pigment mainly composed of carbon black, and 0.3 parts by weight of zinc p-t-butylbenzoate (manufactured by Sakai Chemical Industry Co., Ltd.) were added. Stirring was performed using a two-stage four-paddle paddle as a stirring blade, and steam was introduced from the bottom of the stirring tank. Solvent gas and vapor were condensed with a condenser connected to the upper part of the stirring tank, and the solvent and water were sequentially recovered outside the system. The steam flow rate was adjusted while paying attention to foaming, the steam was stopped 5 minutes after reaching 100 ° C., and cooling was performed using a jacket of a stirring tank to obtain a slurry containing polymer particles, water and a dispersant. The obtained polymer particles were sieved with a standard sieve, the weights of the fractions belonging to the respective particle size ranges were individually weighed, and the average value based on the weight was obtained. The average particle diameter of the obtained polymer particles was 200 μm.

  The slurry containing the polymer particles thus obtained, water and a dispersing agent is allowed to stand for 1 hour, and after removing the supernatant corresponding to 72% of the slurry weight, water is added until the slurry concentration reaches 20% by weight. Was added to a reactor equipped with a stirrer and heated to 60 ° C. The polymer latex produced by the emulsion polymerization method of Production Example 2 was added in an amount of 3.7 parts by weight based on the solid content, and then 5.6 parts by weight of the 15% sodium sulfate solution solid content basis was continuously added over 5 minutes. . Five minutes after the end of the addition, the dispersion was heated to 85 ° C., held at 85 ° C. for 5 minutes, and then cooled to obtain a polymer slurry in which the latex adhered to the surface of the polymer particles. This slurry was dehydrated with a batch centrifugal filter and dried with a batch fluid dryer at a resin temperature of 50 ° C. until the water content reached 0.4%. The obtained powder was passed through a sieve having an opening of 500 μm, and then fine powder of less than 99 μm was removed with a filter having an opening of 99 μm to obtain an acrylic polymer powder having a bulk specific gravity of 0.6 g / cm 3. .

(Production Example 4)
After a slurry was obtained in the same manner as in Production Example 3, the slurry was dehydrated with a continuous centrifugal dehydrator, and dried with a batch fluid dryer until the water content was 0.4% or less under a resin temperature of 60 ° C. The obtained powder was passed through a sieve having an opening of 500 μm to obtain an acrylic polymer powder having a bulk specific gravity of 0.6 g / cm 3.

Example 1
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black as a powder pigment and a pigment dispersant) with respect to 100 parts by weight of 3 kg of the acrylic polymer powder obtained in Production Example 3. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 1 minute, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 parts by weight of Fuji Silysia Chemical Co., Ltd.) was blended for 2 minutes. The powder obtained here is dried again for 2 hours using dehumidified air (0.008 kg / kg), subjected to lab type powder slush molding, evaluation of color unevenness, evaluation of moldability, and using the molded body, A heat resistance test was conducted. It was a result of achieving both heat resistance and color unevenness suppression. Resin volatiles were 0.36%. The results are shown in Table 1.

(Example 2)
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black as a powder pigment and a pigment dispersant) with respect to 100 parts by weight of the 150 kg acrylic polymer powder obtained in Production Example 3. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 2 minutes, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 part by weight of Fuji Silysia Chemical Ltd.) was blended for 3 minutes. The powder obtained here is dried again for 2 hours using dehumidified air (0.008 kg / kg), full powder slush molding is performed, color unevenness evaluation, moldability evaluation, and heat resistance using the molded product. A sex test was performed. It was a result of achieving both heat resistance and color unevenness suppression. Resin volatiles were 0.32%. The results are shown in Table 1.

(Example 3)
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black as a powder pigment and a pigment dispersant) with respect to 100 parts by weight of 3 kg of the acrylic polymer powder obtained in Production Example 4. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 1 minute, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 parts by weight of Fuji Silysia Chemical Co., Ltd.) was blended for 2 minutes. The powder obtained here is dried again for 2 hours using dehumidified air (0.006 kg / kg), subjected to lab type powder slush molding, evaluation of color unevenness, evaluation of moldability, and using the molded body, A heat resistance test was conducted. It was a result of achieving both heat resistance and color unevenness suppression. Resin volatiles were 0.28%. The results are shown in Table 1.

(Comparative Example 1)
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black as a powder pigment and a pigment dispersant) with respect to 100 parts by weight of 3 kg of the acrylic polymer powder obtained in Production Example 3. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 1 minute, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 parts by weight of Fuji Silysia Chemical Co., Ltd.) was blended for 2 minutes. Without dehumidifying the powder obtained here, lab-type powder slush molding was performed as it was, and color unevenness evaluation, moldability evaluation, and the molded body were used to conduct a heat resistance test. The molded product was uneven in color. Resin volatiles were 0.52%. The results are shown in Table 1.

(Comparative Example 2)
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black which is a powder pigment and a pigment dispersant) with respect to 100 parts by weight of 150 kg of the acrylic polymer powder obtained in Production Example 3. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 2 minutes, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 part by weight of Fuji Silysia Chemical Ltd.) was blended for 3 minutes. Without dehumidifying the powder obtained here, full-type powder slush molding was performed as it was, and color unevenness evaluation, moldability evaluation, and the molded body were used to conduct a heat resistance test. The molded product was uneven in color. Resin volatiles were 0.46%. The results are shown in Table 1.

(Comparative Example 3)
A black pigment composition (PV-817 manufactured by Sumika Color Co., Ltd .; carbon black as a powder pigment and a pigment dispersant) with respect to 100 parts by weight of 3 kg of the acrylic polymer powder obtained in Production Example 4. 0.5 parts by weight of calcium carbonate mixed at a ratio of 40/60) is blended for 1 minute, and then added, spherical silica having an average particle diameter of 4.5 μm by laser method, Cyrossphere C-1504 ( 0.5 parts by weight of Fuji Silysia Chemical Co., Ltd.) was blended for 2 minutes. Without dehumidifying the powder obtained here, lab-type powder slush molding was performed as it was, and color unevenness evaluation, moldability evaluation, and the molded body were used to conduct a heat resistance test. The molded product was uneven in color. Resin volatiles were 0.42%. The results are shown in Table 1.

(Comparative Example 4)
The same operation as in Example 3 was performed except that the dehumidified air (0.014 Kg / Kg) was changed. The results are shown in Table 1. The molded product was uneven in color. Resin volatiles were 0.52%. The results are shown in Table 1.

  From Table 1, it can be seen that in Examples 1 to 3, color unevenness is suppressed, whereas in Comparative Examples 1 to 4, color unevenness occurs.

  From the above, it was shown that a molded article excellent in both color unevenness suppression and heat resistance can be obtained by the resin powder of the present invention.

Claims (17)

A resin powder for powder slush molding, which is dried with dehumidified air having a water content of 0.010 kg / kg or less. The resin powder according to claim 1, wherein weight loss by a heat-drying moisture meter (set temperature: 120 ° C) is 0.40% or less. The resin powder includes at least one resin selected from the group consisting of a urethane resin, an ester resin, an epoxy resin, a vinyl chloride resin, and an acrylic resin. The resin powder described. The resin powder according to any one of claims 1 to 3, wherein the resin powder contains an acrylic block copolymer (A). The resin powder according to claim 4, wherein the resin powder contains an acrylic block copolymer (A), an acrylic polymer (B), and a plasticizer (C).
However, the acrylic block copolymer (A) is composed of a methacrylic polymer block (a) mainly composed of a methacrylic polymer and an acrylic polymer block (b) mainly composed of an acrylic polymer. An acrylic block copolymer having an acid anhydride group and / or a carboxyl group in at least one of the methacrylic polymer block (a) and the acrylic polymer block (b). The acrylic polymer (B) is an acrylic polymer having at least 1.1 epoxy groups in one molecule, and the plasticizer (C) is a trimellitic acid ester compound and / or pyromellitic acid. It is a plasticizer made of an ester compound. The resin powder according to claim 1, wherein the resin powder is coated with a polymer latex;
However, the polymer latex is obtained by an emulsion polymerization method using a thioglycolic acid compound as a chain transfer agent, a persulfuric acid compound as a polymerization initiator, and an anionic surfactant as an emulsifier, and forms a latex. Is a polymer latex having a glass transition temperature of 75 ° C. or higher and a weight average molecular weight of 40,000 to 100,000. The resin powder according to claim 5 or 6, wherein an acid anhydride group and / or a carboxyl group are present in the main chain of the acrylic polymer block (b). Acrylic block copolymer (A) is 10-60 wt% of methacrylic polymer block (a) whose main component is a methacrylic monomer, and an acrylic system whose main component is an acrylic monomer. The resin powder according to any one of claims 5 to 7, comprising 90 to 40% by weight of the polymer block (b). The acrylic polymer block (b) is at least one monomer selected from the group consisting of acrylic acid-n-butyl, ethyl acrylate, acrylic acid-2-methoxyethyl and acrylic acid-2-ethylhexyl The resin powder according to any one of claims 5 to 8, comprising 100% by weight and 50 to 0% by weight of a vinyl monomer copolymerizable therewith. The resin powder according to any one of claims 5 to 9, wherein the methacrylic polymer block (a) has a glass transition temperature of 25 to 130 ° C. The resin powder according to any one of claims 5 to 10, wherein the number average molecular weight of the acrylic block copolymer (A) measured by gel permeation chromatography is 30,000 to 200,000. . The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography of the acrylic block copolymer (A) is 1.8 or less. The resin powder according to claim 5. The resin powder according to any one of claims 5 to 12, wherein the acrylic polymer (B) has a weight average molecular weight of 30,000 or less. The resin powder according to any one of claims 5 to 13, wherein the acrylic block copolymer (A) comprises a block copolymer produced by an atom transfer radical polymerization method. The resin according to any one of claims 5 to 14, wherein the plasticizer (C) is 0.1 to 30 parts by weight with respect to 100 parts by weight of the acrylic block copolymer (A). powder. A powder slush molding using the resin powder according to any one of claims 1 to 15. An automotive interior skin comprising the resin powder according to any one of claims 1 to 15.