JP2011073902A - Talc powder and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a talc powder suitably used in a resin composition that is excellent in balance between physical properties and specific gravity and can be used for various applications such as interior and exterior articles for automobiles, components of household electric appliances and components of business machines. <P>SOLUTION: The talc powder is obtained through wet grinding and/or classification of talc ore, provided that the talc ore has a half value width of the 12th-order diffraction peak of 1-30 degrees as measured in an orientation analysis by a wide-angle X-ray diffraction method. The talc powder has a median diameter D50 (L) of 2.0-9.4 μm as measured by a laser diffraction method according to JIS R1629. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a talc powder having a specific form and a method for producing the same. More specifically, the present invention relates to a talc powder suitably used for a resin composition suitably used for automobile parts, home appliance parts, office equipment parts, and the like, and a method for producing the same.

  Conventionally, a resin composition in which talc is blended with propylene / ethylene copolymer resin, etc. exhibits excellent mechanical properties, thermal properties, recyclability, etc. Widely used in parts field. On the other hand, as the development in these fields spreads, the above resin composition is required to have a higher level of physical properties. In order to meet these demands, for example, various attempts have been made to improve rigidity and impact resistance by adding various talc, ethylene / α-olefin copolymer rubber and the like to propylene / ethylene copolymer resin ( (See Patent Documents 1 and 2).

However, since the specific gravity of such a talc-containing resin composition increases as the amount of talc increases, further improvement is desired. For example, for automobile applications, weight reduction is required from the viewpoint of global warming prevention, CO ₂ emission regulations, etc., and it is necessary to reduce the specific gravity of components mounted on vehicles. Therefore, a resin composition used for the above parts is required to have a low specific gravity and high rigidity while having a flexural modulus similar to that of the prior art.

  Moreover, since the molded object using these resin compositions has a large linear expansion coefficient, a dimension may change by the change of external temperature. The linear expansion coefficient can be improved by blending fillers, but further improvement is desired in order to replace conventional metal parts with resin composition parts. Patent Document 3 proposes to use talc having a specific shape in order to solve these problems, but this method requires a drying step and the like because talc is produced by a wet method. There was a problem that it was difficult to scale up and the manufacturing cost was high.

Japanese Unexamined Patent Publication No. 57-73033 Japanese Laid-Open Patent Publication No. 57-8235 International Publication No. 98/45374

  In view of such a current situation, the present invention provides a talc powder that is excellent in a physical property-specific gravity balance and that is suitably used for a resin composition that can be used in various applications such as automobile interior and exterior products, home appliance parts, and office equipment parts. The purpose is to provide.

  As a result of intensive research to solve the above-mentioned problems, the present inventors have bent a resin composition containing a talc powder having a specific shape obtained by wet-grinding and / or classifying a raw talc having a specific crystal structure. The present inventors have found that the mechanical properties such as the elastic modulus are excellent and the physical property-specific gravity balance can be improved, and the present invention has been achieved.

  That is, the first gist of the present invention is a talc powder obtained by wet-grinding and / or classification of talc raw stone, and a half of the twelfth diffraction peak in the orientation evaluation by wide-angle X-ray diffraction method of the talc raw stone. A talc powder having a value range of 1 to 30 degrees and a median diameter D50 (L) measured by a laser diffraction method in accordance with JIS R1629 of the talc powder is 2.0 to 9.4 μm Exist.

The second gist of the present invention is the talc powder described in the first gist, wherein the median diameter D50 (S) measured by the centrifugal sedimentation method of the talc powder measured according to JIS R1619 is 1.0 μm or more and 6.0 μm or less. The aspect ratio constant determined by the following formula of the talc powder is 1.0 or more and 15.0 or less.
Aspect ratio constant = {D50 (L) −D50 (S)} / D50 (S)

  The third gist of the present invention is a median diameter obtained by measuring a rough talc stone having a half-value width of a 12th-order diffraction peak of 1 degree or more and 30 degrees or less in orientation evaluation by a wide-angle X-ray diffraction method according to JIS R1629 by a laser diffraction method. Dry pulverization until D50 (L) is 10 μm or more and 100 mm or less, then wet pulverization, and classify talc powder having a median diameter D50 (L) of 2.0 μm or more and 9.4 μm or less measured by laser diffraction method according to JIS R1629 The talc powder is produced by the following method.

  The fourth gist of the present invention resides in a talc powder obtained by the method for producing talc powder described in the third gist.

  A fifth aspect of the present invention is characterized in that the talc powder described in any one of the first, second, and fourth aspects is deaerated and compressed to a bulk density of 0.3 to 1.0. Lies in compression talc.

  Since the talc powder of the present invention is in a specific form, it is possible to make the molded article of the resin composition containing the talc powder of the present invention lightweight and excellent in mechanical properties such as flexural modulus. is there.

  Hereinafter, the present invention will be described in detail with reference to embodiments, examples, etc., but the present invention is not limited to the following embodiments, examples, etc., and can be arbitrarily set within the scope of the present invention. Can be changed and implemented.

1. Rough talc powder The talc powder of the present invention is obtained by dry pulverization and / or classification of talc rough having a specific crystal structure. Specifically, the talc powder of the present invention is obtained by dry-grinding and / or classifying raw talc having a half-value width of the 12th-order diffraction peak in the orientation evaluation by the wide-angle X-ray diffraction method of 1 degree to 30 degrees. . Further, the half width is preferably 25 degrees or less, and more preferably 20 degrees or less. Further, the degree of orientation of the talc rough calculated from the half width is preferably 0.7 or more, more preferably 0.8 or more, particularly preferably 0.9 or more, The upper limit is preferably 1.0. Here, the half width of the twelfth diffraction peak and the degree of crystal orientation of the talc raw stone can be measured as follows.

(Crystal structure)
The half width of the twelfth diffraction peak is CuKα rays monochromatized with a Ni filter using a tabletop rotary anti-cathode X-ray generator “ultrax18” manufactured by Rigaku Corporation, using a scintillation counter and a wave height analyzer. Thus, it can be obtained by measuring the X-ray diffraction intensity. Here, the optical system is a reflection method, and the divergence slit is ½ °, the light receiving slit is 0.15 mm, and the scattering slit is ½ °. Specifically, the diffraction intensity in the range of 2θ = 5 to 80 ° (2θ is a Bragg angle) is recorded by the symmetric reflection method while irradiating the cleaved surface of talc with the X-rays emitted from the X-ray source. For the measurement of the degree of orientation, a 12th-order diffraction peak observed near 2θ = 59.3 ° is used. The scintillation counter is set at a position of 2θ = 59.3 °, and θ = 0 to 60 ° (θ is a Bragg angle and 1/2 of 2θ) to record the diffraction intensity. At this time, the scan speed is 5 ° / min and the sampling is 0.02 °. [0012] The intensity distribution (I (θ)) of the diffraction peak is curve-fitted with a Gaussian function expressed by the following equation, and the calculated value is defined as the half width. A smaller half-value width means that the diffraction peak is sharper and highly oriented.

I (θ) = a + bexp [− {(θ−c) / d} ² ]
a, b, c: Variables optimized by curve fitting Half width = 2d (ln2) ^1/2

Further, the degree of orientation of the talc powder given by the following formula from the half width is preferably 0.7 or more, more preferably 0.8 or more, particularly preferably 0.9 or more, The upper limit is preferably 1.0. The degree of completeness of orientation is lower as the degree of orientation is closer to 0 and higher as it is closer to 1.
Degree of orientation = (180−half width) / 180

  Talc rough with such a crystal structure is produced in various regions such as pink talc rough from Haicheng District, Liaoning Province, China, talc rough from Guangxi Autonomous Region, Uttar Pradesh, India, and Rajasthan, India. Of these talc ores, those having the above-mentioned preferred crystal structure may be used.

  The reason why talc powder having a specific shape obtained by wet-grinding and / or classifying raw talc having the above-mentioned specific crystal structure can impart excellent mechanical properties such as flexural modulus to the resin is unknown. However, it is estimated as follows. That is, the fact that the “half-value width of the 12th-order diffraction peak” in the orientation evaluation by the wide-angle X-ray diffraction method is small indicates that the orientation degree of the crystals of the 12 layers is uniform. Therefore, if the crystal plane of the talc rough according to the present invention is highly oriented, the talc filler is easily refined while being peeled during the talc grinding process, so that it becomes a powder with a high aspect ratio. It is considered that the flexural modulus of the molded body is improved.

  The shape of the rough talc is not particularly limited as long as the excellent effect of the present invention is exhibited. In the method for producing talc powder of the present invention, the state before dry pulverization is used as talc raw stone.

2. Method for producing talc powder The method for producing talc powder of the present invention may be any method as long as the method is a wet production method capable of obtaining the talc powder of the present invention. Specific examples of the method for producing talc powder include a method in which talc raw stones are mechanically pulverized until the desired particle size is reached, and a method in which talc raw stones are mechanically pulverized and then classified. Here, pulverization and / or classification may be performed only once, or may be performed twice or more using the same or different apparatuses. Among these methods, the method of classifying after pulverization is particularly preferable because the aspect ratio constant of the obtained talc powder can be easily obtained. Hereinafter, although this especially preferable method is explained in full detail, the manufacturing method of the talc powder of this invention is not limited to this.

(Pulverization)
For pulverizing the raw talc, a pulverizer generally used for talc production or the like can be used as a pulverizer. Even if the pulverization is performed only once with one pulverizer, the talc rough is coarsely pulverized (primary pulverization) to increase the pulverization efficiency, and then further pulverized (secondary pulverization) with the same or different pulverizer. May be. The coarse pulverization and fine pulverization may be performed only once, or may be performed twice or more using the same or different apparatus. However, in terms of production cost, the coarse pulverization and fine pulverization are performed once each. Is preferred.

  When pulverization is performed in two steps, talc is usually crushed to a size that can be charged into a fine pulverizer by coarse pulverization, and then further pulverized by fine pulverization. The diameter of the talc after coarse pulverization is preferably smaller in view of easy pulverization with a fine pulverizer and a small load on the fine pulverizer. Specifically, the diameter of the talc after coarse pulverization is usually usually 10 cm or less, preferably 8 cm or less, more preferably 5 cm or less. Suitable crushers for coarse crushing include crusher-type dry crushers such as hammer crushers, jaw crushers, and roll crushers because they are suitable for crushing large stones.

  The fine pulverization performed after the coarse pulverization may be performed by a dry method or a wet method. However, it is preferable to carry out at least once by a wet method from the viewpoint of easily obtaining a preferred form of talc powder. Hereinafter, each of a case where pulverization is performed by a dry method and a case where pulverization is performed by a wet method will be described. In the present invention, the pulverization by the dry method means the case where any pulverization is performed by the dry method, and the pulverization by the wet method is pulverized once or a plurality of times. The case where the wet process is performed at least once is said.

  When pulverizing by a dry method, the particle size of talc after pulverization is less likely to reduce the flatness of talc particles due to excessive pulverization, and the flexural modulus of the resin composition containing the talc powder of the present invention tends to be high. On the other hand, the larger one is preferable, but on the other hand, the content effect of talc powder in the resin composition containing the talc powder of the present invention, particularly the point that the flexural modulus tends to be high and the yield when classification is easy to be large. Then, the smaller one is preferable. Specifically, the diameter of the talc after pulverization is preferably 10 μm or more, more preferably 11 μm or more, particularly preferably 12 μm or more, and on the other hand, preferably 25 μm or less. More preferably, it is 19 μm or less. Here, the particle diameter is a median diameter D50 (L) measured by a laser diffraction method described later.

  Examples of the dry pulverization method suitable for fine pulverization include a grinding pulverization method, an impact pulverization method, and a collision pulverization method. The grinding type pulverization method is a method of pulverizing talc so as to be crushed. Specific examples of such machines include VX roller mills, 5R type Raymond mills, 4R type Raymond mills, vertical mills, and stone mill type pulverizers such as mass colloiders. The impact pulverization method is a method of pulverizing powder by applying an impact with a pulverizer. Specific examples of the machine include an atomizer, a pulverizer, a hammer mill, a micron mill, a bevel impactor, a pin mill, a super micron mill, and a pin mill. The collision type pulverization method is a method of pulverizing powder by collision. Specific examples of the machine include a jet type pulverizer such as a dry fluidized bed jet mill; and a pulverizer such as a ball mill such as a near mill, a planetary ball mill, and a continuous tube mill. In addition, when using the grinder with which the classifier is incorporated in the fine grinder, you may classify, grind | pulverizing.

  When fine pulverization is performed by a wet method, the coarsely pulverized talc powder may be wet pulverized as it is, or the coarsely pulverized talc powder may be further pulverized by a dry method and then wet pulverized. In terms of ease, it is preferable that the coarsely pulverized talc powder is further dry pulverized and then wet pulverized, and it is particularly preferable that this further dry pulverization is performed by the above-described dry pulverization method suitable for fine pulverization and then wet pulverized. In the wet pulverization, coarsely pulverized talc powder is brought into contact with water and pulverized in the form of a slurry having a flowable viscosity. When contacting with water, a dispersant may be appropriately used. Examples of apparatuses suitable for wet grinding include a ball mill, a bead mill, a wet jet mill, a discoplex, and the like. Among these, a ball mill is preferable because it does not cause a decrease in flatness due to overgrinding and is easily pulverized.

(Dry)
The talc powder crushed by the wet method is usually used after being dried. Drying may be performed before or after classification, which will be described later.

(Classification)
The particle size of the pulverized talc is adjusted by classification. As for classification, either dry classification after dry pulverization, dry classification after wet pulverization, dry classification by contacting with water after dry pulverization, wet classification after wet pulverization, etc. The method may be used. In the classification, talc fine powder having a target particle size can be taken out by adjusting the conditions of the classifier. The classifier may be incorporated in the pulverizer or may be an apparatus different from the pulverizer, but it is preferable that the classifier is separate from the pulverizer because over-pulverization hardly occurs. Moreover, when the talc before classification is large, classification may be repeated a plurality of times.

  Examples of the dry classifier include a cyclone, a cyclone air separator, a micro separator, a cyclone air separator, a sharp cut separator, a wind separator ("YACA-132" manufactured by Yaskawa Seisakusho), and turbo classifier (Nisshin Engineering Co., Ltd.) Manufactured by Nippon Pneumatic Co., Ltd. “DSF”, “DXF”, “UFC”), slurry screener, and the like. Further, the wet classification can be performed using, for example, a discoplex, a water tank classification method, or the like.

3. Talc powder The talc powder of the present invention usually has the following specific form.

(Median diameter D50 (L) measured by laser diffraction method)
The median diameter D50 (L) of the n6 talc powder of the present invention measured by a laser diffraction method in accordance with JIS R1629 is 2.0 μm or more and 9.4 μm or less. The smaller median diameter is preferable in terms of surface impact resistance of the molded resin composition containing talc powder. On the other hand, the larger median diameter is a resin composition containing talc powder because the talc powder has a flat structure. This is preferable in terms of the flexural modulus of the molded body. Therefore, the median diameter is preferably 3.0 μm or more, more preferably 4.0 μm or more, and preferably 9.0 μm or less.

  The median diameter D50 is obtained from a particle size value of 50% by weight accumulated from a particle size cumulative distribution curve measured in accordance with JIS R1629 using a laser method particle size distribution measuring machine. As a laser method particle size distribution measuring instrument, for example, it can be measured by “LA920” manufactured by Horiba, Ltd., “SALD-2000J” manufactured by Shimadzu Corporation.

(Median diameter D50 (S) by centrifugal sedimentation)
About the talc powder of this invention, it is preferable that the median diameter D50 (S) by the centrifugal sedimentation method measured according to JISR1619 is 1.0 micrometer or more and 6.0 micrometers or less. The smaller the median diameter, the easier the surface impact resistance of the resin composition molded body containing talc powder becomes, and the talc powder has a flat structure, and the flexural elasticity of the resin composition molded body containing talc powder. It is preferable in that the rate tends to be excellent. Specifically, the median diameter is preferably 1.5 μm or more, more preferably 1.7 μm or more, and on the other hand, 5.0 μm or less is preferable, and 4.0 μm or less. More preferably.

  The median diameter can be measured by, for example, “CP” manufactured by Shimadzu Corporation, using a centrifugal sedimentation particle size distribution analyzer. The measurement is obtained from the particle size value of 50% by weight cumulative amount read from the measured particle size cumulative distribution curve according to JIS R1619.

(Aspect ratio constant)
About the talc powder of this invention, it is preferable that the aspect-ratio constant calculated | required by the following formula from the value of said two types of median diameters is 1.0-15.0.
Aspect ratio constant = {D50 (L) −D50 (S)} / D50 (S)

  A larger aspect ratio constant is preferable in terms of the flexural modulus of the resin composition molded article according to the present invention, while a smaller aspect ratio is preferred in terms of surface impact resistance of the resin composition molded article according to the present invention. Is preferable. Therefore, specifically, the aspect ratio constant is more preferably 1.3 or more, particularly preferably 2.0 or more, and more preferably 7.0 or less. It is particularly preferred that the ratio is.

(surface treatment)
The talc powder of the present invention may be subjected to a surface treatment for the purpose of improving the adhesiveness and dispersibility to a resin or the like. Examples of the surface treatment include treatment with an organic titanate coupling agent, an organic silane coupling agent, a modified polyolefin grafted with an unsaturated carboxylic acid or its anhydride, a fatty acid, a fatty acid metal salt, a fatty acid ester, and the like. Of these, fatty acid metal salts are preferred.

  Specific examples of the surface treatment agent include saturated and / or unsaturated fatty acids such as lauric acid, stearic acid, behenic acid, montanic acid and erucic acid; and metal salts such as magnesium, calcium, lithium, zinc and sodium. These ester compounds; maleic acid modified products such as maleated polypropylene, maleated polyethylene, maleated SEBS; silane-based coupling agents; titanate-based coupling agents or zircoaluminate-based coupling agents. Of these, metal salts of saturated fatty acids are preferred, and magnesium or calcium salts of stearic acid are particularly preferred.

  In particular, for the purpose of improving adhesiveness, a silane coupling agent is preferable, and specifically, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyl. Trimethoxysilane, vinyltriethoxysilane, vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -Γ-aminopropyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like. Of these, aminosilane coupling agents such as γ-aminopropyltrimethoxysilane and N-β- (aminoethyl) -γ-aminopropyldimethoxysilane are particularly preferable.

  As a surface treatment method, for example, a talc powder is immersed in a 0.01 to 1.00% by weight aqueous solution or a water dispersion of the above surface treatment agent, and then heat treatment is performed at 140 to 160 ° C. for 1 to 2 hours. And the like.

(Compression processing)
The talc powder of the present invention may be compressed. Compressed talc compressed from talc powder can be stored compactly, and the bulk density increases, so the amount of air brought into the kneader when melt kneading with the resin is reduced, making it difficult for feed necks to occur. There is an advantage that the amount of compound production per unit time is increased by increasing the bite to the machine. When the talc powder is compressed talc, it is preferable to deaerate before compression because the compression efficiency is easily improved. Hereinafter, a method of compressing talc powder after deaeration to form compressed talc will be described, but the method for producing compressed talc of the present invention is not limited to this.

  Degassing of talc can be performed by a conventionally known apparatus and method. Examples of the degassing volume reduction machine include “Kuripack” manufactured by Kurimoto Seiko Co., Ltd., “Denspack” manufactured by Hosokawa Micron Corporation, and the like.

  The compression can be performed by a conventionally known apparatus and method. At the time of compression, it is preferable to adjust the pressure or the like so as not to form a mass that is difficult to break. Examples of the apparatus used for the compression include a roller compactor manufactured by Kurimoto Seiko Co., Ltd.

  The bulk density of the compressed talc is preferable because the smaller one is less likely to cause white spots on the molded product based on the generation of lumps due to uneven compression. On the other hand, the larger one can be stored more compactly and when melt-kneaded with resin. Since the amount of air brought into the kneading machine is small, feed necks and the like are hardly generated, and the bite property to the melt kneading extruder is increased, the production amount of the compound per unit time is preferably increased. Specifically, the bulk density of talc after compression, measured based on JIS K-6720, is usually 0.30 or more, preferably 0.40 or more, and more preferably 0.45 or more. The bulk density of talc before compression is usually 1.00 or less, preferably 0.90 or less, more preferably 0.60 or less. In addition, the same bulk density of the talc powder before compression is usually 0.10 or more, preferably 0.11 or more, more preferably 0.12 or more, and usually 0.50 or less, preferably 0.00. 35 or less, more preferably 0.25 or less.

  As for the compression rate of talc by compression, the lower one is preferable in that white spots of molded products are less likely to occur due to the generation of lumps due to uneven compression. On the other hand, the higher one can be stored compactly and when melt-kneaded with resin Since the amount of air brought into the kneading machine is small, feed necks and the like are hardly generated, and the bite property to the melt kneading extruder is increased, the production amount of the compound per unit time is increased, which is preferable. The compression rate of talc by compression is usually 3.1 or more, preferably 3.2 or more, as a value obtained by dividing the bulk density before air compression by the bulk density after degassing, and usually 7.0. Hereinafter, it is preferably 6.5 or less, and more preferably 5.5 or less.

4). Resin Composition A molded product obtained by molding a resin composition containing the talc powder of the present invention can be excellent in mechanical properties such as flexural modulus while being lightweight. The resin composition containing the talc powder of the present invention is usually prepared by melt-kneading the talc powder of the present invention and a resin.

5). Applications The resin composition containing the talc powder of the present invention is excellent in the balance between physical properties and specific gravity, and thus is suitably used for automobile parts, home appliance parts, office equipment parts and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples without departing from the gist thereof. The evaluation methods of materials and molded products used in Examples and Comparative Examples are as follows.

[I] Measurement Method (1) Half-width of 12th-order diffraction peak in wide-angle X-ray diffraction method The half-width of the 12th-order diffraction peak in wide-angle X-ray diffraction method is a tabletop rotary anti-cathode X-ray manufactured by Rigaku Corporation. Using a generator “ultrax18”, the X-ray diffraction intensity was measured with a CuKα ray monochromated with a Ni filter using a scintillation counter and a wave height analyzer. Here, the optical system is a reflection method, and the divergence slit is ½ °, the light receiving slit is 0.15 mm, and the scattering slit is ½ °. Specifically, the diffraction intensity in the range of 2θ = 5 to 80 ° (2θ is a Bragg angle) was recorded by a symmetric reflection method while irradiating the cleaved surface of talc with X-rays emitted from an X-ray source. For the measurement of the degree of orientation, a 12th-order diffraction peak observed near 2θ = 59.3 ° was used. The scintillation counter was set at a position of 2θ = 59.3 °, and θ = 0 to 60 ° (θ is a Bragg angle and 1/2 of 2θ) was scanned to record the diffraction intensity. At this time, the scan speed was 5 ° / min, and sampling was 0.02 °. [0012] The intensity distribution (I (θ)) of the diffraction peak was curve-fitted with a Gaussian function expressed by the following equation, and the calculated value was defined as the half width.

I (θ) = a + bexp [− {(θ−c) / d} ² ]
a, b, c: Variables optimized by curve fitting Half width = 2d (ln2) ^1/2

(2) Degree of orientation The degree of orientation was calculated from the above half width according to the following formula.
Degree of orientation = (180−half width) / 180

(3) Median diameter D50 (L) by laser diffraction method
The median diameter D50 (L) by the laser diffraction method was read from the particle size cumulative distribution curve obtained by measuring in accordance with JIS R1629 using a laser diffraction particle size distribution analyzer ("LA920" manufactured by Horiba, Ltd.). It was determined from the particle size value of a cumulative amount of 50% by weight.

(4) Median diameter D50 (S) by centrifugal sedimentation
The median diameter D50 (S) by the centrifugal sedimentation method was measured using a centrifugal sedimentation particle size distribution analyzer (“SA-CP2-20” manufactured by Shimadzu Corporation) according to JIS R1619, with a centrifugal rotation speed of 600 rpm and a cell surface level. It was determined from the particle size value of 50% by weight accumulated read from the particle size cumulative distribution curve measured under the condition of 3 cm height.

(5) Aspect ratio constant The aspect ratio constant was calculated | required by the following formula from the value of said two types of median diameters.
Aspect ratio constant = {D50 (L) −D50 (S)} / D50 (S)

(6) Flexural modulus The flexural modulus was measured in accordance with JIS-K7171 for a test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm at 23 ° C., a distance between fulcrums of 64.0 mm, and a test speed of 2.0 mm / min. did.

(7) Melt flow rate (MFR)
The melt flow rate was measured at a temperature of 230 ° C. with a 2.16 kg load according to ASTM-D1238.

(8) Viscosity [η] copolymer of ethylene / propylene-random copolymer part eluted at 100 ° C. or lower
The intrinsic viscosity [η] copolymer of the ethylene / propylene-random copolymer portion in the propylene / ethylene block copolymer was determined as follows. First, after the polymerization of the crystalline propylene homopolymer portion was completed, a portion was sampled from the polymerization tank, and the intrinsic viscosity [η] homo of the portion was measured. Next, after polymerizing the crystalline propylene homopolymer part, the intrinsic viscosity [η] F of the final polymer (F) obtained by polymerizing the ethylene / propylene-random copolymer part was measured, and the following It was obtained from the relational expression. This measurement was performed at a temperature of 135 ° C. using decalin as a solvent using an Ubbelohde viscometer.
[Η] F = (100−Wc) / 100 × [η] homo + Wc / 100 × [η] copoly

(9) Surface impact characteristics The surface impact characteristics of the molded body were injection molded under the conditions of a cylinder temperature of 220 ° C. and a mold temperature of 40 ° C. using an injection molding machine with a clamping pressure of 7 tons (“IS170FII” manufactured by Toshiba Corporation). 120 mm x 120 mm x 3 mm test piece was stored in a constant temperature room at 23 ° C for 5 days, and then measured according to ASTM-D790 using a punch diameter of 1.2 inches and a falling surface measured at a fall speed of 5 m / sec. Measurement was performed by impact, and 5 samples were measured, and when 4 or more of the 5 samples were brittlely broken, the case of 3 or less was evaluated as ◯.

[Example 1]
Talc rough from Rajasthan, India (Golcha Associated Soapstone Dist. Co. Pvt. Ltd., full width half maximum of the 12th diffraction peak in wide angle X-ray diffraction method 13.9, degree of orientation 0.92) (Rough 1) Was roughly pulverized to a particle size of 10 mm or less using a jaw crusher, and then finely pulverized and classified by a VX mill with a built-in classifier impact pulverizer. Place 1.0 kg of the talc powder, 6 kg of alumina balls with a long diameter of 20 mm, and 2.0 kg of water into a 7 liter ball mill, grind them at 45 rpm for 24 hours, remove the alumina balls, and transfer to a 3 liter container. After that, the mixture was stirred with a propeller type stirrer to disperse the talc powder in water. After standing for 15 hours, 1 liter of the supernatant was taken, and after classifying it with waterpox, it was filtered, washed with water, dried, and crushed with a cutter mill. The median diameter D50 (L) measured by the laser diffraction method of the obtained talc powder was 8.5 μm, the median diameter D50 (S) by the centrifugal sedimentation method was 2.4 μm, and the aspect ratio constant was 2.54. It was.

[Example 2]
Talc rough from Rajasthan, India (Golcha Associated Soapstone Dist. Co. Pvt. Ltd., full width half maximum of the 12th diffraction peak in wide angle X-ray diffraction method 13.9, degree of orientation 0.92) (Rough 1) Was roughly pulverized to a particle size of 10 mm or less using a jaw crusher, and then finely pulverized and classified by a VX mill with a built-in classifier impact pulverizer. Place 1.0 kg of the talc powder, 6 kg of alumina balls with a long diameter of 20 mm, and 2.0 kg of water into a 7 liter ball mill, grind them at 45 rpm for 24 hours, remove the alumina balls, and transfer to a 3 liter container. After that, the mixture was stirred with a propeller type stirrer to disperse the talc powder in water. After standing for 15 hours, 1 liter of the supernatant was taken, and after classifying it with waterpox, it was filtered, washed with water, dried, and crushed with a cutter mill. The median diameter D50 (L) measured by the laser diffraction method of the obtained talc powder was 6.7 μm, the median diameter D50 (S) by the centrifugal sedimentation method was 1.9 μm, and the aspect ratio constant was 2.53. It was.

[Example 3]
Rough talc from Uttar Pradesh, India (manufactured by Golcha Associated Soapstone Dist. Co. Pvt. Ltd., FWHM of twelfth-order diffraction peak in wide-angle X-ray diffraction method 8.3, degree of orientation 0.95) ( The rough 2) was coarsely pulverized to a particle size of 10 mm or less using a jaw crusher, and then finely pulverized and classified by a VX mill with a built-in classifier impact pulverizer. Place 1.0 kg of the talc powder, 6 kg of alumina balls with a long diameter of 20 mm, and 2.0 kg of water into a 7 liter ball mill, grind them at 45 rpm for 24 hours, remove the alumina balls, and transfer to a 3 liter container. After that, the mixture was stirred with a propeller type stirrer to disperse the talc powder in water. After standing for 15 hours, 1 liter of the supernatant was taken, and after classifying it with waterpox, it was filtered, washed with water, dried, and crushed with a cutter mill. The obtained talc powder had a median diameter D50 (L) measured by laser diffraction of 6.6 μm, a median diameter D50 (S) by centrifugal sedimentation of 2.0 μm, and an aspect ratio constant of 2.30. It was.

[Example 4]
Talc rough from Rajasthan, India (Golcha Associated Soapstone Dist. Co. Pvt. Ltd., full width half maximum of the 12th diffraction peak in wide angle X-ray diffraction method 13.9, degree of orientation 0.92) (Rough 1) Was roughly pulverized to a particle size of 10 mm or less using a hammer mill. Place 1.0 kg of the talc powder, 6 kg of alumina balls with a long diameter of 20 mm, and 2.0 kg of water into a 7 liter ball mill, grind them at 45 rpm for 24 hours, remove the alumina balls, and transfer to a 3 liter container. After that, the mixture was stirred with a propeller type stirrer to disperse the talc powder in water. After standing for 15 hours, 1 liter of the supernatant was taken, and after classifying it with waterpox, it was filtered, washed with water, dried, and crushed with a cutter mill. The median diameter D50 (L) measured by the laser diffraction method of the obtained talc powder was 6.7 μm, the median diameter D50 (S) by the centrifugal sedimentation method was 1.9 μm, and the aspect ratio constant was 2.53. It was.

[Comparative Example 1]
Coarse crushed white lump talc from Liaoning Province, China (32 half-width of the 12th-order diffraction peak in wide-angle X-ray diffraction method. Orientation 0.82) (Rough 4) using jaw crusher After that, fine pulverization and classification were performed by a classifier built-in type impact pulverizer VX mill. Place 1.0 kg of the talc powder, 6 kg of alumina balls with a long diameter of 20 mm, and 2.0 kg of water into a 7 liter ball mill, grind them at 45 rpm for 24 hours, remove the alumina balls, and transfer to a 3 liter container. After that, the mixture was stirred with a propeller type stirrer to disperse the talc powder in water. After standing for 15 hours, 1 liter of the supernatant was taken, and after classifying it with waterpox, it was filtered, washed with water, dried, and crushed with a cutter mill. The median diameter D50 (L) measured by the laser diffraction method of the obtained talc powder was 8.3 μm, the median diameter D50 (S) by the centrifugal sedimentation method was 3.0 μm, and the aspect ratio constant was 1.77. It was.

[Polypropylene resin compositions containing talc powder of Examples 1 to 4 and Comparative Example 1]
After blending 20 parts by weight of talc powders of Examples 1 to 4 and Comparative Example 1 and 80 parts by weight of propylene / ethylene block copolymer C, tetrakis [methylene-3- (3'5'-di-t-butyl- 4′-hydroxyphenyl) propionate] 0.1 part by weight of methane (“Irganox 1010” manufactured by Ciba Japan Co., Ltd.) and 0.4 part by weight of magnesium stearate were blended and mixed for 5 minutes using a super floater. Then, the thermoplastic resin composition was obtained by kneading and granulating at 210 degreeC with a biaxial kneading machine ("KCM50" made by Kobe Steel Co., Ltd.). A test piece was produced at an molding temperature of 220 ° C. using an injection molding machine having a clamping pressure of 100 tons, and various physical properties were measured. The evaluation results are shown in Table 1.

(Propylene / ethylene block copolymer)
Propylene / ethylene block copolymer C (PP-C. Melt flow rate of crystalline propylene homopolymer part is 30 g / 10 min. Content of ethylene / propylene-random copolymer part is 14% by weight. The ethylene content in the propylene-random copolymer portion was 61% by weight, and the viscosity [η] c of the ethylene / propylene-random copolymer portion was
oply is 3.3).

  The talc powder of the present invention can make a molded article of a resin composition containing the talc powder excellent in mechanical properties such as bending elastic modulus while being lightweight, and is used for automobile parts, home appliance parts, office work. It is suitably used for equipment parts.

Claims (5)

  A talc powder obtained by wet pulverization and / or classification of talc rough, wherein the half width of the 12th diffraction peak in the orientation evaluation by wide-angle X-ray diffraction method of the talc rough is 1 degree or more and 30 degrees or less, The talc powder has a median diameter D50 (L) measured by a laser diffraction method in accordance with JIS R1629 of the talc powder of 2.0 μm or more and 9.4 μm or less. The talc powder according to claim 1, wherein the talc powder has a median diameter D50 (S) measured by a centrifugal sedimentation method in accordance with JIS R1619 of 1.0 µm or more and 6.0 µm or less, and Talc powder characterized by having an aspect ratio constant of 1.0 or more and 15.0 or less determined by the formula.
Aspect ratio constant = {D50 (L) −D50 (S)} / D50 (S)   The median diameter D50 (L) measured by laser diffraction method according to JIS R1629 for a talc rough whose FWHM of the 12th order diffraction peak is 1 degree or more and 30 degrees or less in orientation evaluation by wide angle X-ray diffraction method is 10 μm or more and 100 mm or less. Talc powder characterized by obtaining a talc powder having a median diameter D50 (L) of 2.0 μm or more and 9.4 μm or less measured by laser diffractometry according to JIS R1629 Manufacturing method.   A talc powder obtained by the method for producing talc powder according to claim 3.   A compressed talc, wherein the talc powder according to any one of claims 1, 2, and 4 is deaerated and compressed to a bulk density of 0.3 to 1.0.