Talcum powder, resin property improving agent, and resin composition

Abstract

The talc powder has a B / A value of 0.10 or less when A (m2 / g) is the BET specific surface area and B (mass%) is the weight loss rate as determined by thermogravimetric differential thermal analysis at 200-700 DEG C.

Description

Technical Field

[0001] The present disclosure relates to talc powder, a resin property improver, and a resin composition. Background Art

[0002] When producing a resin molded body, various filler materials are incorporated into a resin raw material for the purpose of improving properties such as mechanical strength. As such a filler material, for example, general talc. Talc is the softest among rock-forming minerals, has cleavage and is easily exfoliated, has a slippery feel, and is also chemically stable, and thus is widely used by being mixed with various raw materials.

[0003] Talc is applied to a wide range of fields such as plastics (resins), paper making, cosmetics, pharmaceuticals, fertilizers, coatings, and ceramics due to its excellent versatility. For example, resin compositions containing talc are widely used in various fields such as automotive parts, home appliance parts, or office equipment parts.

[0004] On the other hand, with the advancement of technologies in various fields, there is an increasing tendency to achieve a high level of property at the stage of material design. For general talc, various improvements have also been made in order to bring out its originally effective properties.

[0005] For example, Patent Document 1 proposes a talc which is a granular talc obtained by degassing powder talc having an average primary particle size of 0.1 to 10 μm without directly compressing it and then compressing it, and has a bulk density of 0.6 to 0.94 g / cm 3 , and a breakage rate of 70 to 100% by weight.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-104794 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] However, in Patent Document 1, although the dispersibility was studied in the case of adding it to a thermoplastic resin and melt-mixing, the study on whether the resin properties (for example, properties such as flexural modulus of elasticity) can be improved was not conducted. That is, it cannot be said that a high level of property is achieved at the stage of material design.

[0011] In view of the above, an object of the present invention is to provide a talc powder which can improve the resin properties when a resin composition is prepared by adding the talc powder as compared with the case of adding an existing talc powder.

[0012] Technical Means for Solving the Technical Problem

[0013] In order to solve the above problems, intensive studies have been carried out. As a result, the present inventors have found that the following present invention can solve the technical problems. That is, the present invention is as described below.

[0014] [1] A talc powder, when the BET specific surface area is A (m 2 / g) and the weight reduction rate obtained by thermogravimetric differential thermal analysis at 200 to 700 °C is B (mass %), B / A is 0.10 or less.

[0015] [2] The talc powder according to [1], wherein the BET specific surface area is 3 to 20 m 2 / g.

[0016] [3] The talc powder according to [1] or [2], having a bulk density of 0.05 to 0.35 g / cm 3 .

[0017] [4] The talc powder according to any one of [1] to [3], having a median particle size (D50) of 1 to 10 μm.

[0018] [5] A resin property improver comprising the talc powder according to any one of [1] to [4].

[0019] [6] A resin composition comprising the talc powder according to any one of [1] to [4] and a resin.

[0020] [7] A resin composition comprising the resin property improver according to [5] and a resin.

[0021] Advantages of the Invention

[0022] According to the present invention, a talc powder can be provided which, when added to a resin composition, can improve the resin properties as compared with the case of adding an existing talc powder. Detailed Description of the Invention

[0023] [Talc Powder]

[0024] In the talc powder of an embodiment (this embodiment) of the present invention, when the BET specific surface area is A (m 2 / g) and the weight reduction rate obtained by thermogravimetric differential thermal analysis at 200 to 700 °C is B (mass %), B / A is 0.10 or less.

[0025] The above B / A being 0.10 or less indicates that the amount of moisture present on the existing talc powder is very low. That is, it can be inferred that the surface of the talc powder becomes a state with improved hydrophobicity, thereby improving the affinity with the resin and improving the properties of the resin (especially the elastic modulus).

[0026] B / A is preferably from 0.02 to 0.09, more preferably from 0.025 to 0.085.

[0027] In addition, the weight reduction rate B obtained based on thermogravimetry differential thermal analysis can be determined and obtained, for example, by the following method using a known device.

[0028] Put 7 mg of talc powder sample into a differential thermal balance (for example, manufactured by Rigaku Corporation, device name: ThermoPlus2) and raise the temperature (room temperature to 950 °C). At this time, obtain the weight reduction rate (mass %) from 200 °C to 700 °C. The heating rate is set to 10 °C / min. The measurement atmosphere is preferably a nitrogen atmosphere.

[0029] From the viewpoint of the manifestation of the effect caused by hydrophobicity, the weight reduction rate B (mass %) is preferably 1.2 mass % or less, more preferably 1 mass % or less, and further preferably 0.7 mass % or less. The lower limit is not particularly limited and is actually about 0.05 mass %.

[0030] In order to make B / A in this embodiment 0.10 or less, for example, it is preferable to pulverize the raw talc under conditions of higher temperature and higher shear force than the pulverization conditions of a normal jet mill. Specifically, it is preferable to use a pulverization method such as the steam jet mill described later, which can instantaneously impart high shear force at a high temperature using superheated steam (saturated steam and steam obtained by further heating saturated steam) as the fluid energy, and adjust the temperature, pressure, etc. to produce.

[0031] In this embodiment, the tapped density of the talc powder is preferably 0.05 to 0.35 g / cm 3 、more preferably 0.10 to 0.30 g / cm 3 、even more preferably 0.13 to 0.28 g / cm 3 。By being 0.05 to 0.35 g / cm 3 , it is easy to obtain a higher elastic modulus when mixed with the resin.

[0032] The above-mentioned tapped density indicates that the talc powder in this embodiment is in a state of very large volume. Generally, considering the operability such as transportation, the particle size and aspect ratio of the talc powder are designed optimally on the premise of increasing the tapped density. In contrast, in this embodiment, the present invention is achieved with the concept of not being restricted by common technical knowledge by focusing on the "state of low tapped density (= state of very large volume)" that is easily excluded from common technical research.

[0033] Here, the bulk density can be obtained from the tapped bulk density measured using a powder property evaluation device (PowderTester PT-X manufactured by Hosokawa Micron Corporation). The measurement conditions are as follows: The sample is supplied to a sieve with a mesh size of 710 μm, and the sample is added in such a way that the powder surface position of the lid covering the cup for bulk density measurement becomes constant by vibration with an amplitude of 1.5 mm, and 180 taps are performed. 3 The bulk density measurement cup is covered with a lid, and the powder surface position becomes constant by vibration with an amplitude of 1.5 mm, and 180 taps are performed.

[0034] In addition, from the viewpoint of obtaining a high elastic modulus when mixed with a resin, the median particle size (volume basis, D50) of the talc powder of the present embodiment is preferably 1 to 10 μm, more preferably 1.5 to 9.5 μm, and still more preferably 1.7 to 8.5 μm. In addition, D50 is preferably 2.3 to 8 μm, more preferably 2.3 to 7 μm.

[0035] Here, the median particle size can be obtained by measuring the particle size distribution using a laser diffraction particle size distribution measuring device (SALD-200V ER manufactured by Shimadzu Corporation) and using the median particle size (D50: the particle size at a cumulative volume of 50% from the small particle size side) on a volume basis.

[0036] The specific surface area (BET specific surface area) of the talc powder of the present embodiment is preferably 3 to 20 m 2 / g, preferably 3 to 18 m 2 / g, more preferably 6.0 to 16.0 m 2 / g, still more preferably 6.5 to 15.0 m 2 / g, even more preferably 6.5 to 14.0 m 2 / g.

[0037] When the specific surface area is 3 to 20 m 2 / g, a high elastic modulus can be obtained when mixed with a resin.

[0038] Here, the specific surface area can be measured and obtained by using a specific surface area and pore size distribution measuring device (BELSORP MINIII manufactured by Micro track·bell Corporation). As for sample preparation, it is preferably dried using a vacuum dryer at 100 °C for 90 minutes.

[0039] In the talc powder of the present embodiment, natural talc (non-synthetic talc) is preferred compared to synthetic talc. Synthetic talc is talc produced by chemical synthesis, for example, obtained by hydrothermal synthesis in which raw materials containing magnesium and silicon are heated under pressure at a high temperature. On the other hand, natural talc is a naturally occurring mineral. Natural talc sometimes contains calcium carbonate, dolomite, etc. as trace components. Such trace components function to improve impact resistance when added to a resin. Therefore, as the talc powder of the present embodiment, natural talc powder is preferred.

[0040] [Manufacturing Method of Talc Powder]

[0041] The manufacturing method of the talc powder of the present embodiment includes a pulverizing step of pulverizing raw talc with a steam jet mill.

[0042] As described above, in the pulverization treatment using a steam jet mill, since superheated steam is used as the fluid energy for pulverization, a high shear force can be instantaneously imparted. Therefore, compared to a jet mill under general conditions using compressed air as the fluid energy, a large shear force acts instantaneously on the raw talc powder, so that the surface moisture is efficiently removed, and good hydrophobicity is exhibited. Therefore, it can be considered that when mixed with a resin to form a resin composition, it is easy to exhibit the effect of improving the properties originally possessed by the talc powder at a high level.

[0043] In the pulverization treatment using a steam jet mill, for example, it is preferable to set the temperature of the superheated steam pulverized by the steam jet mill (the temperature before entering the pulverization zone) to 300 to 500 °C, and it is preferable to set the pressure of the superheated steam (pulverization pressure) to 3.5 to 15.0 MPa in terms of gauge pressure.

[0044] By appropriately adjusting within the above ranges, it is possible to set the above-mentioned B / A, bulk density, specific surface area, average particle diameter (D50), etc. to a desired range.

[0045] In addition, superheated steam can be generated at a desired temperature using a commercially available boiler and superheater (steam superheater), etc.

[0046] In addition, the median particle diameter D0 of the raw talc is preferably 11 to 20 μm, and the bulk density is preferably 0.5 to 2 g / cm 3 . By being within these ranges, good pulverization efficiency can be obtained, and it is easy to obtain the talc powder of the present embodiment.

[0047] The talc powder (pulverized talc powder) obtained as described above can be applied to various uses according to need after classification treatment, etc.

[0048] [Resin Property Improver]

[0049] The resin property improver of this embodiment includes the talc powder of this embodiment. By mixing this resin property improver with a resin (for example, a thermoplastic resin described later), the resin properties (especially the elastic modulus) can be improved. That is, it is suitable as a resin property improver for addition to a resin (including a resin composition).

[0050] From the viewpoint of fully exerting its effects, the content of the talc powder of this embodiment in the resin property improver is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 100%.

[0051] In the resin property improver, for example, a surface treatment agent such as a silane coupling agent or an acid-modified polymer (for example, maleic acid-modified PP, etc.) may also be contained.

[0052] [Resin Composition]

[0053] The resin composition of this embodiment includes the above-mentioned talc powder of this embodiment (or the above-mentioned resin property improver of this embodiment) and a resin.

[0054] Examples of the resin include: thermoplastic resins (including thermoplastic elastomers for convenience), thermosetting resins, rubbers, and cellulose-based resins.

[0055] Examples of the above-mentioned thermoplastic resins include: polypropylene, polyethylene, 4-methylpentene-1 resin, polybutene-1 resin, ethylene-propylene random copolymer, ethylene-propylene block copolymer, propylene-1-butene copolymer, propylene-ethylene-butene-1 copolymer, propylene-4-methylpentene copolymer, ethylene-butene-1 copolymer, ethylene-hexene copolymer, ethylene-heptene copolymer, ethylene-octene copolymer, ethylene-4-methylpentene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylate copolymer and other olefin resins; styrene homopolymer, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin) and other styrene resins; polyvinyl chloride, polyvinylidene chloride; polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene resin, polyvinylidene fluoride and other fluororesins; polyvinyl alcohol; polyamide resins such as nylon 6, nylon 6,6, nylon 6,10, nylon 11, nylon 12, nylon 6,12, polyhexamethylene diamine terephthalamide, polyhexamethylene diamine isophthalamide, polyamide containing xylylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate; acrylic resins such as polymethyl acrylate, polymethyl methacrylate; polyoxymethylene homopolymer, polyoxymethylene copolymer and other polyoxymethylene resins; polycarbonate; polyacetal; polyphenylene ether; polyethersulfone; polyetherketone; liquid polyester, etc.

[0056] Examples of the above-mentioned thermoplastic elastomers include polyolefin thermoplastic elastomers, polystyrene thermoplastic elastomers, polyester thermoplastic elastomers, polyamide thermoplastic elastomers, low-crystallinity 1,2-polybutadiene thermoplastic elastomers, fluorine thermoplastic elastomers, chlorinated polymer thermoplastic elastomers, ion-crosslinked thermoplastic elastomers, etc.

[0057] Examples of the above-mentioned thermosetting resins include phenolic resins, urea resins, melamine resins, alkyd resins, thermosetting acrylic resins, unsaturated polyester resins, diallyl phthalate resins, epoxy resins, thermosetting silicone resins, thermosetting polyimides, thermosetting resins derived from cyclopentadiene, thermosetting resins derived from aromatic nitriles; furan resins, ketone resins, xylene resins, thermosetting resins containing condensed polycyclic aromatics, etc.

[0058] Examples of the above-mentioned rubbers include: natural rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, isoprene rubber, isobutene-isoprene rubber, butyl rubber, ethylene-propylene rubber, acrylonitrile-butadiene rubber, nitrile rubber, silicone rubber, fluororubber, acrylic rubber, epichlorohydrin rubber, etc.

[0059] Examples of the above cellulose-based resins include: cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, ethyl cellulose, nitrocellulose, etc.

[0060] In one embodiment of the present invention, the content of talc powder is preferably 0.5 to 60 parts by mass, more preferably 1 to 35 parts by mass, based on 100 parts by mass of the resin in the resin composition.

[0061] The resin composition of one embodiment of the present invention may, if necessary, contain one or more of an antioxidant, a heat stabilizer, a weather resistance improver, a release agent, a lubricant, a pigment, a dye, a plasticizer, an antistatic agent, a flame retardant, etc. Further, if necessary, it may also contain a filler other than the talc powder of one embodiment of the present invention. Examples of such a filler include: calcium carbonate, clay, synthetic silica, titanium oxide, carbon black, barium sulfate, mica, glass fiber, whisker, carbon fiber, magnesium carbonate, kaolin, graphite, molybdenum disulfide, zinc oxide, etc.

[0062] Furthermore, depending on the use, a solvent or a dispersion medium may also be contained to form a liquid resin composition.

[0063] The compounding and kneading of talc powder into the resin can be carried out by a known method. For example, the compounding and kneading into polypropylene can be carried out using a commonly used single-screw kneading extruder or a twin-screw kneading extruder, etc.

[0064] In addition, the resin composition of the present embodiment can be used for various applications such as automotive interior and exterior parts, home appliance parts, and office equipment parts.

[0065] Examples

[0066] Next, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[0067] [Talc powder]

[0068] The raw talc with a median particle size (D50) of 12.7 μm and a bulk density of 0.72 g / cm 3 (the talc produced in Pakistan was roughly pulverized with a roll mill to obtain the above D50) was pulverized into each median particle size shown in Table 1 using a steam jet mill (hereinafter, sometimes referred to as "s-JET") and a jet mill, respectively.

[0069] (1) Pulverization conditions using a steam jet mill

[0070] · The device used was a steam / jet mill s-JET150 manufactured by Netzsch Trockenmahltechnik.

[0071] · The temperature of superheated steam (temperature before entering the pulverization zone): 360 °C

[0072] · Crushing pressure (gauge pressure): 3.8 MPa

[0073] In addition, the particle size adjustment is performed by adjusting the rotation speed of the classifier attached to the steam jet mill.

[0074] (2) Crushing conditions using the jet mill

[0075] · The device uses a counter jet mill AFG710 / 4 manufactured by Hosokawa Micron Corporation. The particle size adjustment is performed by adjusting the rotation speed of the classifier attached to the jet mill.

[0076] In addition, in the case of D50 = 2.2 μm (Comparative Example 1), classification is performed after crushing for adjustment.

[0077] In s-JET, large-volume crushed talc powder is obtained. On the other hand, in the jet mill, when observed at the same D50 as s-JET, small-volume crushed talc powder is obtained. It is considered that this is because, in the case of a jet mill under normal conditions, the residence time of crushing is long, so not only the shearing force but also the isotropic force acts on the talc, and thus further crushing is performed not only limited to surface peeling.

[0078] (Resin composition)

[0079] The evaluation of the resin composition prepared using the talc powder prepared as described above was carried out as follows.

[0080] Evaluation: Flexural modulus of elasticity

[0081] The flexural modulus of elasticity was measured in accordance with JIS K7171. The results are shown in Table 2.

[0082] Injection molding of the resin composition was carried out using a mold for injection molding (JIS K7171 type B1), and the flexural modulus of elasticity (temperature: 23 °C, bending speed: 2 mm / min) of the molded product thus obtained (10 mm (width) × 4 mm (thickness) × 80 mm (length)) was evaluated in accordance with JIS K7171 using AutoGragh AG-Xplus Co., Ltd.

[0083] [Table 1]

[0084]

[0085] According to Table 1, compared with Comparative Examples 1 to 3, Examples 1 to 3 with B / A of 0.10 or less can improve the resin properties. That is, it is suitable as a resin property improver for addition to resins or resin compositions.

Claims

1. A talc powder, Set the BET specific surface area to A (m 2 / g), and the B / A when the weight reduction rate obtained by thermogravimetric differential thermal analysis at 200 to 700 °C is B (mass%) is 0.10 or less.

2. The talc powder according to claim 1, The BET specific surface area is 3 to 20 m 2 / g.

3. The talc powder according to claim 1, The bulk density is 0.05 to 0.35 g / cm 3 .

4. The talc powder according to claim 1, having a median particle size D50 of 1 to 10 μm.

5. A resin property improver, which comprises the talc powder according to any one of claims 1 to 4.

6. A resin composition, which comprises the talc powder according to any one of claims 1 to 4 and a resin.

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