Filler and resin composition

Abstract

Provided is a filler which contains a polar plate-shaped powder having an aspect ratio (median diameter / average thickness) of 8 or more and a non-polar plate-shaped powder having an aspect ratio of 18 or more, and in which the content of the non-polar plate-shaped powder relative to the total of the polar plate-shaped powder and the non-polar plate-shaped powder is 10-90 mass%.

Description

Filler and resin composition

[0001] This invention relates to fillers and resin compositions.

[0002] Because resins have low strength and high thermal expansion, there are limitations to their use as a substitute for metals. Therefore, development is underway to create composite materials that combine resins with reinforcing materials possessing superior properties such as lightness, high strength, high rigidity, and low thermal expansion.

[0003] For example, glass fibers are widely used as reinforcing agents for resins such as polyolefins and polyamides. For instance, Patent Document 1 describes a polyamide resin composition that has improved tensile strength, flexural modulus, and low warpage, as well as improved weld properties and enhanced burr suppression during molding.

[0004] Japanese Patent Publication No. 2012-214560

[0005] However, during the mixing process, the fiber length of the glass fibers is significantly shortened, which can reduce the resin reinforcing properties during recycling, or the glass fibers can damage the furnace material during thermal recycling.

[0006] Therefore, there is a need for a resin composition that can replace glass fibers and exhibit similar properties. Against this backdrop, various fillers to be added to resins have been investigated, but a filler that exhibits high modulus of elasticity and high strength comparable to glass fiber-filled resin compositions, and furthermore, can also exhibit impact strength, has yet to be developed.

[0007] Based on the above, the present invention aims to provide a filler that can achieve good strength, elastic modulus, and impact strength when used in a resin molded article.

[0008] As a result of diligent research to solve the above problems, the inventors focused on the polarity and shape of the filler added to the resin and found that the above problems could be solved by controlling them to a specific state. In other words, the present invention is as follows.

[0009] [1] A filler comprising polar plate-shaped powder having an aspect ratio (median diameter / average thickness), which is the ratio of the median diameter to the average thickness, of 8 or more, and non-polar plate-shaped powder having an aspect ratio of 18 or more, wherein the content of the non-polar plate-shaped powder relative to the total of the polar plate-shaped powder and the non-polar plate-shaped powder is 10 to 90% by mass. [2] The filler according to [1], wherein the ratio of the median diameter of the polar plate-shaped powder to the median diameter of the non-polar plate-shaped powder (median diameter of polar plate-shaped powder / median diameter of non-polar plate-shaped powder) is 0.09 to 4.5. [3] The filler according to [1] or [2], wherein the ratio of the average thickness of the polar plate-shaped powder to the average thickness of the non-polar plate-shaped powder (average thickness of polar plate-shaped powder / average thickness of non-polar plate-shaped powder) is 0.25 to 7.0. [4] The filler according to any one of [1] to [3], wherein the total content of the polar plate-shaped powder and the non-polar plate-shaped powder in the filler is 90% by mass or more. [5] The filler according to any one of [1] to [4], wherein the polar plate-shaped powder is kaolin powder. [6] The filler according to any one of [1] to [5], wherein the non-polar plate-shaped powder is talc powder. [7] A resin composition comprising the filler according to any one of [1] to [6] and a resin, wherein the filler is present in an amount of 10% by mass or more. [8] The resin composition according to [7], wherein the resin is polyamide.

[0010] According to the present invention, a filler can be provided that exhibits good strength, elastic modulus, and impact strength (impact resistance) when formed into a resin molded article. In particular, resin compositions containing mineral powders such as talc powder and kaolin powder as fillers, as predetermined non-polar plate-shaped powders and polar plate-shaped powders, can become composite materials that are suitable for both material recycling and thermal recycling, unlike resin compositions using glass fibers and the like.

[0011] [Filler] The filler according to one embodiment of the present invention is a filler comprising polar plate-shaped powder having an aspect ratio (median diameter / average thickness), which is the ratio of the median diameter to the average thickness, of 8 or more, and non-polar plate-shaped powder having an aspect ratio of 18 or more.

[0012] Polar plate-like powders can bond more strongly to polar resins, such as polyamides, than to hydrogen bonds, thus improving the strength of the molded resin article. On the other hand, non-polar plate-like powders easily form crazing at the interface with polar resins. Therefore, when an impact is applied to a molded resin article, delamination (interfacial delamination) occurs near the interface, absorbing and mitigating the impact energy, resulting in good impact strength. Furthermore, non-polar plate-like powders can improve the elastic modulus. It is believed that by setting the content of non-polar plate-like powders to 10 to 90% by mass relative to the total of polar and non-polar plate-like powders, the above effects can be effectively exhibited, resulting in good strength, elastic modulus, and impact strength of the molded resin article.

[0013] Here, the average thickness of the polar plate-like powder and the non-polar plate-like powder (hereinafter sometimes collectively referred to as "plate-like powder") is preferably determined by cross-sectional observation of a cross section perpendicular to the length direction of the resin molded body, in a state where the plate-like particles are oriented and dispersed in the length direction of the molded body. Furthermore, polar plate-like powder is a plate-like powder that is polar because it has more hydrophilic groups than hydrophobic groups, and non-polar plate-like powder is a plate-like powder that is non-polar because it has more hydrophobic groups than hydrophilic groups. Examples of each are described later.

[0014] (Non-polar plate-shaped powder) As described above, the non-polar plate-shaped powder according to this embodiment has an aspect ratio (median diameter / average thickness), which is the ratio of the median diameter to the average thickness, of 18 or more. If the aspect ratio is less than 18, the strength and / or modulus of elasticity will decrease when it is used to form a resin molded article. The aspect ratio is preferably 19 to 35, and more preferably 20 to 30. In this specification, the aspect ratio of the plate-shaped powder can be measured by the method described in the examples below.

[0015] The median diameter of the non-polar plate-shaped powder is preferably 2 μm or more, more preferably 3 to 9 μm, even more preferably 3 to 8 μm, and most preferably 3 to 7 μm. A median diameter of 2 μm or more ensures sufficient surface area of ​​the non-polar plate-shaped powder, resulting in a good elastic modulus when molded into a resin article. As a result, strength (e.g., tensile strength) is also improved.

[0016] The average thickness of the non-polar plate-like powder is preferably 0.40 μm or less, and more preferably 0.30 μm or less, from the viewpoint of obtaining good strength and / or elastic modulus when formed into a resin molded article. The lower limit of the average thickness of the non-polar plate-like powder is not particularly limited, but in practice it is preferably 0.04 μm or more, more preferably 0.08 μm or more, and even more preferably 0.10 μm or more.

[0017] Examples of non-polar plate-shaped powders include talc powder, boron nitride powder, graphite powder, and graphene powder, with talc powder being preferred from the viewpoint of price, color, and insulating properties. Furthermore, this non-polar plate-shaped powder can be produced by various known methods, such as grinding with a jet mill or water jet, or by grinding with a roller mill followed by classification with an air classifier, but high-aspect-value talc powder obtained by steam jet is more preferred.

[0018] High-aspect-ratio talc powder is preferably produced through a grinding process in which raw talc is ground using a steam jet mill. Since the grinding process using a steam jet mill utilizes superheated steam as the fluid energy for grinding, a high shear force can be instantaneously applied. Therefore, compared to a conventional jet mill using compressed air as the fluid energy, a larger instantaneous shear force acts on the raw talc powder, thereby increasing the aspect ratio.

[0019] In the steam jet milling process, for example, it is preferable to set the temperature of the superheated steam used for steam jet milling (temperature before entering the grinding area) to 300 to 500°C, and the pressure of the superheated steam (grinding pressure) to 3.5 to 15.0 MPa in gauge pressure. By adjusting within the above range as appropriate, the aspect ratio average particle size (D50) and other parameters described above can be set to the desired range. Superheated steam can be generated at the desired temperature using commercially available boilers and superheaters (steam superheaters).

[0020] Furthermore, in the above case, the median diameter of the raw material talc is preferably 11 to 20 μm, and the bulk density is preferably 0.5 to 2 g / cm³. ３ It is preferable that the values ​​are within these ranges. Being within these ranges makes it easier to obtain good grinding efficiency.

[0021] The specific surface area (BET specific surface area) of the non-polar plate-shaped powder in this embodiment is 3 to 20 m². ２ It is preferably 6.0 to 16.0 m / g. ２ It is more preferable that the specific surface area is 3 to 20 m². ２ Being at / g allows for a higher modulus of elasticity when mixed with resin.

[0022] Here, the specific surface area can be determined by measuring it using a specific surface area and pore distribution analyzer (BELSORP MINIII, manufactured by Microtrac-BEL, Inc.). For sample preparation, it is preferable to use a sample that has been dried using a vacuum dryer.

[0023] (Polar plate-shaped powder) As described above, the polar plate-shaped powder according to this embodiment has an aspect ratio (median diameter / average thickness), which is the ratio of the median diameter to the average thickness, of 8 or more. If the aspect ratio is less than 8, the impact resistance will decrease. The aspect ratio is preferably 9 to 60, more preferably 11 to 50, and even more preferably 12 to 20.

[0024] The median diameter of the polar plate-like powder is preferably 1.0 μm or larger, more preferably 2 to 15 μm, even more preferably 2.5 to 11 μm, and most preferably 3 to 9 μm. A median diameter of 1.0 μm or larger allows the polar plate-like powder to exhibit its effects effectively.

[0025] The average thickness of the polar plate-like powder is preferably 0.7 μm or less, and more preferably 0.65 μm or less, from the viewpoint of obtaining good impact resistance when formed into a resin molded article. The lower limit of the average thickness of the polar plate-like particles is not particularly limited, but in practice it is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.6 μm or more.

[0026] Examples of polar plate-shaped powders include kaolin powder, mica powder, plate-shaped alumina powder, smectite powder, and sericite powder. From the viewpoint of price and dispersibility in resin, kaolin powder is preferred. Polar plate-shaped powders can be manufactured by various known methods, such as grinding by water jet, or by grinding with a roller mill, bead mill, or pulperizer followed by classification using an air classifier or the like.

[0027] The specific surface area (BET specific surface area) of polar plate-like powders is 5 to 30 m². ２ It is preferable that the value be / g, and 6 to 28m ２ It is more preferable that the amount be / g, and 10 to 20 m ２ It is even more preferable that the specific surface area is 5 to 30 m². ２ Being at a concentration of / g allows for better elastic modulus, strength (e.g., tensile strength), etc., when mixed with resin.

[0028] The plate-like powder described above may be surface-treated by known methods depending on its application. Examples of surface treatment agents include silane coupling agents, titanate coupling agents, fatty acids, fatty acid metal salts, and fatty acid esters. For example, plate-like particles surface-treated with a silane coupling agent or a titanate coupling agent have improved affinity with the resin they are compounded with. As a result, molded articles of the resin composition exhibit not only excellent tensile strength and tensile elongation at break, but also excellent impact strength and surface hardness.

[0029] The filler according to this embodiment can be prepared by mixing the polar plate-shaped powder and the non-polar plate-shaped powder described above, such that the content of the non-polar plate-shaped powder is 10 to 90% by mass in the total.

[0030] If the non-polar plate-like powder content is less than 10% by mass, the impact strength will decrease when the material is molded into a resin article. Conversely, if it exceeds 90% by mass, the strength (e.g., tensile strength) will decrease when the material is molded into a resin article. The content of non-polar plate-like powder relative to the total of polar plate-like powder and non-polar plate-like powder is preferably 25 to 70% by mass, and more preferably 33 to 65% by mass.

[0031] The ratio of the median diameter of the polar plate-shaped powder to the median diameter of the non-polar plate-shaped powder (median diameter of polar plate-shaped powder / median diameter of non-polar plate-shaped powder) is preferably 0.09 to 4.5, more preferably 0.15 to 4, even more preferably 0.20 to 3, and even more preferably 0.5 to 2, from the viewpoint of effectively exhibiting the effects of each powder.

[0032] The ratio of the average thickness of polar plate-shaped powder to the average thickness of non-polar plate-shaped powder (average thickness of polar plate-shaped powder / average thickness of non-polar plate-shaped powder) is preferably 0.25 to 7.0, more preferably 0.3 to 6, even more preferably 0.35 to 5, and even more preferably 1.5 to 4.5, from the viewpoint of effectively exhibiting the effects of each powder.

[0033] Furthermore, in this embodiment, the total content of polar plate-shaped powder and non-polar plate-shaped powder in the filler is preferably 90% by mass or more, and more preferably 95% by mass or more, from the viewpoint of exhibiting its effects more effectively. If the above total is not 100% by mass, it may contain polar plate-shaped powder and non-polar plate-shaped powder, spherical fillers, and other powders (for example, mineral fillers, organic fillers, metal fillers, etc.) that do not satisfy the aspect ratio of this embodiment.

[0034] As described above, the filler according to this embodiment can be suitably used in resins or resin compositions for producing resin molded articles that are excellent in at least one of strength, elastic modulus, and impact strength.

[0035] [Resin Composition] The resin composition according to this embodiment comprises the filler and resin according to this embodiment, and contains 10% by mass or more of the filler. By containing 10% by mass or more of the filler, the strength, elastic modulus, and impact strength of the resin molded article can all be improved. The content of the filler in the resin composition is preferably 20 to 60% by mass, and more preferably 25 to 50% by mass.

[0036] (Resin) As the resin according to this embodiment, a thermoplastic resin (for convenience, including a thermoplastic elastomer) is preferred. Suitable thermoplastic resins include olefin resins such as 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-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid ester copolymer; styrene-based resins such as styrene homopolymer, acrylonitrile-styrene copolymer (AS resin), and acrylonitrile-butadiene-styrene copolymer (ABS resin); polyvinyl chloride, polyvinylidene chloride; polytetrafluoroethylene, tetrafluoroethylene Examples include fluororesins such as perfluoroethylene / perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene / hexafluoropropylene copolymers, ethylene / tetrafluoroethylene copolymers, polychlorotrifluoroethylene resins, and polyvinylidene fluoride; polyvinyl alcohol; polyamide resins such as nylon 6, nylon 6,6, nylon 6,10, nylon 11, nylon 12, nylon 6,12, polyhexamethylenediamine terephthalamide, polyhexamethylenediamine isophthalamide, and xylene group-containing polyamides; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; acrylic resins such as polymethyl acrylate and polymethyl methacrylate; polyoxymethylene resins such as polyoxymethylene homopolymer and polyoxymethylene copolymer; polycarbonate; polyacetal; polyphenylene ether; polyethersulfone; polyetherketone; and liquid polyester.

[0037] Examples of the thermoplastic elastomer include polyolefin - based thermoplastic elastomers, polystyrene - based thermoplastic elastomers, polyester - based thermoplastic elastomers, polyamide - based thermoplastic elastomers, low - crystallinity 1,2 - polybutadiene - based thermoplastic elastomers, fluorine - based thermoplastic elastomers, chlorinated polymer - based thermoplastic elastomers, ion - crosslinked thermoplastic elastomers, and the like.

[0038] Among the above - mentioned resins, from the viewpoint of more clearly demonstrating the effect of the filler according to the present invention, at least one of polyamide, polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polypropylene, and acrylonitrile - butadiene - styrene copolymer resins is preferable.

[0039] The resin composition according to the present embodiment can contain, if necessary, one or more of an antioxidant, a heat stabilizer, a weather resistance improver, a mold release agent, a lubricant, a pigment, a dye, a plasticizer, an antistatic agent, a flame retardant, etc. Further, if necessary, a filler other than the plate - like powder according to one aspect of the present invention may be contained. Examples of such fillers include calcium carbonate, synthetic silica, titanium oxide, carbon black, barium sulfate, glass fiber, whisker, carbon fiber, magnesium carbonate, graphite, molybdenum disulfide, zinc oxide, etc. Depending on the application, a solvent or a dispersion medium may be contained to form a liquid resin composition.

[0040] The resin composition according to the present embodiment can be produced by blending the filler according to the present embodiment and a resin (for example, a thermoplastic resin) and kneading them by a known method.

[0041] Next, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[0042] [Production of non - polar plate - like powder] The median diameter (D50) is 12.7 μm and the bulk density is 0.72 g / cm ３The raw material talc (talc produced in Pakistan, coarsely pulverized by a roller mill and having the above D50) was pulverized by a steam jet mill (hereinafter sometimes referred to as "s-JET") or a jet mill to produce non-polar plate-like powders A to E having the average thickness, median diameter, specific surface area, and aspect ratio shown in Table 1 below. Note that non-polar plate-like powders A and B were pulverized by a jet mill, and non-polar plate-like powders C to E were pulverized by a steam jet mill.

[0043] (1) The pulverization conditions and apparatus using a steam jet mill were as follows: The steam jet mill s-JET150 manufactured by Netzsch Trockenmahltechnik was used. - Temperature of superheated steam (temperature before entering the pulverization area): 360°C - Pulverization pressure (gauge pressure): 3.8 MPa Note that the particle size adjustment was performed by adjusting the rotation speed of the classifier attached to the steam jet mill.

[0044] (2) The pulverization conditions and apparatus using a jet mill were as follows: The counter jet mill AFG710 / 4 manufactured by Hosokawa Micron Corporation was used. The particle size adjustment was performed by adjusting the rotation speed of the classifier attached to the jet mill.

[0045] [Preparation of polar plate-like powder] Polar plate-like powders a to d having the average thickness, median diameter, specific surface area, and aspect ratio shown in Table 1 were prepared. Note that polar plate-like powder a is kaolin powder manufactured by Imerys, polar plate-like powder b is kaolin powder manufactured by Kamin, polar plate-like powder c is kaolin powder manufactured by Kamin, and polar plate-like powder d is kaolin powder manufactured by Imerys.

[0046] The physical properties of the plate-like powder were determined as follows: (1) Average thickness of the plate-like powder First, a resin composition was prepared by mixing the plate-like powder with polypropylene resin (Sun Allomer PX600N manufactured by Sun Allomer Co., Ltd.) at a concentration of 20% by mass. The prepared resin composition was injection molded to produce a test specimen with a diameter of 13 mm and a length of 123 mm. This test specimen was placed in liquid nitrogen for 1 hour, and fractured near the center of the specimen perpendicular to the longitudinal direction in the liquid nitrogen. It was confirmed that the fracture surface was almost perpendicular to the longitudinal direction and was a smooth surface. The fractured specimens were removed from liquid nitrogen, and their fracture surfaces (cross-sections) were observed using a SEM (Hitachi High-Technologies Corporation, model name SU8220, with optimal magnification selected according to particle size at 3000x or higher). The maximum thickness of the plate-like powder present in the cross-section was measured for 400 samples using measurement software (MACVIEW, Mountec Co., Ltd.) attached to the SEM used, and the average thickness was determined from the volume-based particle size distribution. In addition, the aspect ratio (median diameter / average thickness), etc., was determined from the average thickness and the median diameter described below.

[0047] (2) The median diameter of plate-shaped powder was determined by measuring the particle size distribution of the plate-shaped powder using a laser diffraction / scattering particle size distribution analyzer (SALD-200VER, manufactured by Shimadzu Corporation), thereby determining the volume-based median diameter (D50: particle size at 50% of the cumulative volume from the small particle size side).

[0048]

[0049] [Examples 1-7 and Comparative Examples 1-6] Talc powder and kaolin powder were mixed in the proportions (mass%) shown in the table below to form a filler. This filler was then mixed with nylon 6 (Amiran CM1017, manufactured by Toray Industries, Inc.) and stirred and mixed using a blender at 150 rpm for 10 minutes. After that, a resin composition was prepared by melt kneading using a twin-screw kneader (Laboplastmill 4C150, manufactured by Toyo Seiki Seisakusho Co., Ltd.). Injection molding was performed under kneading conditions of 230°C, 25 rpm, and a kneading time of 10 minutes to obtain the specified dumbbell pieces (JIS K7113). The obtained dumbbell pieces were conditioned for about one day, and the tensile modulus, tensile strength, and impact strength were evaluated. The results are shown in the table below. The injection molding die used in the injection molding process conformed to ASTM D638 Type I.

[0050] (1) Tensile modulus The tensile modulus of the dumbbell pieces was evaluated using an Autograph AG-5000E from Shimadzu Corporation in accordance with ISO 527-1,2. In the table, 0° is the modulus of elasticity of the dumbbell piece cut in the glass short fiber molding flow direction, 45° is the modulus of elasticity of the dumbbell piece cut at an angle of 45° to the said flow direction, and 90° is the modulus of elasticity of the dumbbell piece cut at an angle of 90° to the said flow direction. For the evaluation, glass fibers (product name: ECS03T-249, manufactured by Nippon Electric Glass Co., Ltd., fiber diameter: 12 μm, fiber length: 3 mm) were mixed with nylon 6 (product name: Amiran CM1017, manufactured by Toray Industries, Inc.), and the result of 0° of a reference resin composition (glass fibers in Table 2) containing 30% by mass of glass fibers prepared in the same manner as in Example 1 was used as the baseline (100%), and the percentage increase or decrease from the baseline was determined. (2) Tensile strength The tensile strength of the dumbbell pieces was evaluated using an Autograph AG-5000E from Shimadzu Corporation in accordance with ISO 527-1,2. In the table, 0° is the tensile strength of the dumbbell piece cut in the glass short fiber molding flow direction, 45° is the tensile strength of the dumbbell piece cut at an angle of 45° to the said flow direction, and 90° is the tensile strength of the dumbbell piece cut at an angle of 90° to the said flow direction. For the evaluation, the result of 0° of the reference resin composition (glass fiber in Table 2) described above was used as the baseline (100%), and the percentage increase or decrease from the baseline was calculated. (3) DuPont drop impact test (impact test) The dumbbell pieces were evaluated using a DuPont impact tester from Toyo Seiki Mfg. Ltd. in accordance with JIS K 5600-5-3. The evaluation was based on the results of the reference resin composition described above (glass fiber in Table 2), with the result set as the baseline (100%), and the percentage increase or decrease from that baseline was calculated.

[0051]

[0052]

[0053] From the results above, in all examples, the impact resistance was better than that of glass fibers. Furthermore, the tensile modulus and tensile strength were slightly lower than those of glass fibers at 0°, but better at 45° and 90°. In other words, compared to the case where glass fibers were randomly oriented, the tensile modulus and tensile strength were superior in both the examples. On the other hand, the comparative examples tended to have lower impact resistance or lower tensile modulus and tensile strength compared to those of glass fibers.

Claims

1. A filler comprising polar plate-shaped powder having an aspect ratio (median diameter / average thickness), which is the ratio of the median diameter to the average thickness, of 8 or more, and non-polar plate-shaped powder having an aspect ratio of 18 or more, wherein the content of the non-polar plate-shaped powder relative to the total of the polar plate-shaped powder and the non-polar plate-shaped powder is 10 to 90% by mass.

2. The filler according to claim 1, wherein the ratio of the median diameter of the polar plate-shaped powder to the median diameter of the non-polar plate-shaped powder (median diameter of polar plate-shaped powder / median diameter of non-polar plate-shaped powder) is 0.09 to 4.

5.

3. The filler according to claim 1, wherein the ratio of the average thickness of the polar plate-shaped powder to the average thickness of the non-polar plate-shaped powder (average thickness of polar plate-shaped powder / average thickness of non-polar plate-shaped powder) is 0.25 to 7.

0.

4. The filler according to claim 1, wherein the total content of the polar plate-shaped powder and the non-polar plate-shaped powder in the filler is 90% by mass or more.

5. The filler according to claim 1, wherein the polar plate-shaped powder is kaolin powder.

6. The filler according to claim 1, wherein the non-polar plate-shaped powder is talc powder.

7. A resin composition comprising a filler and a resin according to any one of claims 1 to 6, wherein the filler is present in an amount of 10% by mass or more.

8. The resin composition according to claim 7, wherein the resin is a polyamide.

Images