JPH0144251B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] This invention is reinforced with fibrous magnesium oxysulfate, which is a fibrous filler, and calcium carbonate, which is a non-fibrous filler, and is suitable for use in technical fields such as automobiles and light electrical appliances. The present invention relates to a polypropylene resin composition that can be used as a polypropylene resin composition. [Prior Art and its Problems] Polypropylene resin compositions reinforced with inorganic fillers are widely used as important materials mainly in the fields of industrial materials such as automobiles and light electrical appliances. This is because when an inorganic filler is blended into a polypropylene resin, the mechanical properties and the like of the polypropylene resin composition can be improved. Naturally, the mechanical property values of a polypropylene resin composition generally required in the technical field related to automobiles and the mechanical property values of the polypropylene resin composition required in the technical field related to light electricity are different. In any field, for example, in order to improve rigidity, increasing the amount of inorganic filler blended into polypropylene resin can improve rigidity, but there is a tendency that impact strength decreases. In addition, in both the automotive and light electrical fields, it maintains the required rigidity and impact strength, maintains a beautiful surface appearance even when heated during molding, and prevents deformation such as warping. Materials that do not exist are required. However, conventionally, for example, polypropylene resin compositions reinforced with fibrous fillers, mainly glass fibers, have significantly improved rigidity, but have also resulted in a decrease in impact strength and a deterioration in the surface appearance of molded products. , warpage, deformation, etc.
Furthermore, although polypropylene resin compositions reinforced with non-fibrous fillers such as talc do not have the above-mentioned drawbacks, they have problems such as little improvement in strength, heat-resistant rigidity, etc. This invention has been made based on the above circumstances. That is, the object of the present invention is to (1) provide superior rigidity and/or impact strength compared to conventional polypropylene resin compositions containing inorganic fillers for the same amount of inorganic fillers; (2) Compared to conventional polypropylene resin compositions containing inorganic fillers, if the impact strength is the same, the rigidity is greater; (3) Compared to conventional polypropylene resin compositions containing inorganic fillers, Compared to polypropylene resin compositions, if the rigidity is the same, the impact strength is greater. (4) While achieving the above (1) to (3), the molded product has a beautiful surface appearance, and is suitable for use in automobiles, for example. It is an object of the present invention to provide a polypropylene resin composition as a material suitable for fields such as electricity. In order to achieve the above object, the inventor conducted intensive research and found that fibrous magnesium oxysulfate having a specific average fiber diameter and aspect ratio and calcium carbonate having a specific average particle diameter were mixed in specific proportions. The present inventors have discovered that the objects of the present invention, which are the contents of (1) to (4) above, can be achieved by blending them into a polypropylene resin. [Means for solving the above problems] The outline of this invention for achieving the above objects is as follows:
42-92% by weight of polypropylene resin and 3-3% fibrous magnesium oxysulfate having an average fiber diameter of 0.1-2μ and an aspect ratio of 20-60.
40% by weight of calcium carbonate and 5 to 40% by weight of calcium carbonate having an average particle diameter of 0.1 to 0.8μ. The polypropylene resin in this invention is not particularly limited as long as it is generally used as a molding material. Therefore, propylene homopolymers, copolymers of propylene and α-olefin, such as so-called propylene-ethylene block copolymers, propylene-ethylene random copolymers, etc. can be used. Among the various polypropylenes mentioned above, crystalline polypropylene homopolymers, propylene-ethylene block copolymers and propylene-ethylene random copolymers are preferred. Further, the polypropylene resin preferably has a melt index (MI) of 2 to 30 g/10 minutes, particularly preferably 3 to 20 g/10 minutes. The fibrous magnesium oxysulfate in this invention has an average fiber diameter of 0.1 to 2μ,
Preferably the aspect ratio is 0.5 to 1μ.
It is important that it is between 20 and 60, preferably between 30 and 50. When the average fiber diameter is smaller than 0.1μ, the bulk specific gravity becomes too small, making it difficult to blend with other components, and even if blending is possible, the fibrous magnesium oxysulfate will not be easily dispersed. Further, if the average fiber diameter exceeds 2 μ and the aspect ratio exceeds 60, the surface appearance of a molded article formed using this polypropylene resin composition will be poor. The average fiber diameter is 2μ
If the aspect ratio exceeds 20 and the aspect ratio is less than 20, the improvement in rigidity of a molded article formed using this polypropylene resin composition will be small. It is important that the calcium carbonate in this invention has an average particle diameter of 0.1 to 0.8μ, preferably 0.15 to 0.7μ. If the average particle diameter of this calcium carbonate is less than 0.1μ, the dispersibility of calcium carbonate will be poor. Furthermore, if the average particle diameter exceeds 0.8 μ, the impact strength of molded articles molded using this polypropylene resin composition decreases. The calcium carbonate used in this invention is not particularly limited as long as it satisfies the above conditions. What is important in this invention is that the polypropylene resin composition contains 40 to 92% by weight, preferably 50 to 85% by weight of the polypropylene resin, and 3 to 40% by weight, preferably 5 to 30% by weight of the fibrous magnesium oxysulfate. %, and 5 to 40% by weight, preferably 10 to 30% by weight of the calcium carbonate. If the blending amount of the fibrous magnesium oxysulfate is less than 3% by weight, the rigidity of the molded product of this polypropylene resin composition will not improve, and if it exceeds 40% by weight, the strength of the polypropylene resin composition itself will not improve. This makes manufacturing difficult, and even if it can be manufactured, the impact strength of molded articles made from this polypropylene resin composition will be reduced. If the amount of calcium carbonate is less than 5% by weight, not only will the impact strength of the molded product of this polypropylene resin composition not improve, but the molded product will not be effective in suppressing warpage. If the amount of calcium carbonate exceeds 40% by weight, the impact strength of the molded article will decrease and the specific gravity of the polypropylene resin composition will increase, making handling and molding disadvantageous. In order to maintain a good surface appearance of the molded product when molding the polypropylene resin composition of the present invention at high temperatures, it is preferable to further blend calcium oxide or a calcium oxide-containing substance into the polypropylene resin composition. . The amount of the calcium oxide or the calcium oxide-containing material is based on a total of 100 parts by weight of the polypropylene resin composition, the fibrous magnesium oxysulfate, and the calcium carbonate.
It is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. When calcium oxide or a calcium oxide-containing substance is blended within the range of 0.1 to 10 parts by weight, even if the polypropylene resin composition is molded at high temperatures, no silver streaks will occur on the surface of the resulting molded product, resulting in a good appearance. There is no loss of sexuality.
If the blending amount exceeds 10% by weight, the impact strength of the polypropylene resin composition may decrease. Further, the average particle size of the calcium oxide or calcium oxide-containing material to be blended is preferably 30μ or less, particularly preferably 1 to 0.1μ. If the average particle size exceeds 30 μm, the surface appearance of the molded product of the polypropylene resin composition may deteriorate and the impact strength may decrease. There are no particular restrictions on calcium oxide as long as it satisfies the above conditions, and calcium oxide-containing materials include those whose main component is calcium oxide,
Calcium oxide to aluminum-magnesium
An inorganic ceramic crystal composite obtained by reaction firing with a silica-based catalyst is preferred. This inorganic ceramic crystal composite is available, for example, under the trade name "AEROTSUKU" (manufactured by Suzuhiro Chemical Co., Ltd.). In this invention, in addition to the calcium oxide or the calcium oxide-containing material, one or more of a silane coupling agent and a modified polyolefin are added to the mixture of the polypropylene resin, the fibrous magnesium oxysulfate, and the calcium carbonate. When a seed is blended, the mechanical strength is improved, and when one or both of polyethylene and elastomer are blended, the impact strength of a molded article of a polypropylene resin composition can be improved. Examples of the silane coupling agent include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltrichlorosilane, vinyldichloroethylsilane, vinylchlorodiethylsilane,
Vinyltris (β-methoxyethoxysilane),
γ-glycidoxypropyltrimethoxysilane,
γ-aminopropyltriethoxysilane, γ-methacroxypropyltrimethoxysilane, N-β
-(aminoethyl)-γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-
Examples include aminopropylmethyldiethoxysilane. Examples of the modified polyolefin include:
unsaturated carboxylic acids, derivatives of unsaturated carboxylic acids,
Examples include polyethylene, polypropylene, and ethylene-propylene copolymers modified with chlorine and vinylsilane. Examples of the unsaturated carboxylic acid used for the modification include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid,
Angelic acid, etc., and derivatives of the unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, metal salts, etc., such as maleic anhydride, itaconic anhydride, citraconic anhydride,
Examples include methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, monoethyl maleate, acrylamide, maleic acid monoamide, maleimide, N-butylmaleimide, sodium acrylate, and sodium methacrylate. Among the various modified polyolefins, polypropylene modified with maleic anhydride is particularly preferred. Examples of the elastomer include styrene-ethylene-butadiene-styrene rubber (S-E
Styrenic elastomers such as -B-S), styrene-butadiene-styrene rubber (S-B-S), styrene-isoprene-styrene rubber (S-I-S), and styrene-butadiene rubber (S-B), ethylene Olefin elastomers such as propylene rubber and ethylene propylene diene rubber are preferred, and styrene-butadiene rubber, ethylene propylene rubber and the like are particularly preferred. The amount of the silane coupling agent and modified polyolefin to be blended is usually 0.1 to 5 parts by weight based on a total of 100 parts by weight of the polypropylene resin composition, the fibrous magnesium oxysulfate, and calcium carbonate. The blending amount is 0.1
If the amount is less than 5 parts by weight, no improvement in mechanical strength may be observed, and if the amount is more than 5 parts by weight, improvement in mechanical strength will not be achieved as described above, and the cost will increase. There will be a disadvantage in terms of The amount of polyethylene and elastomer to be blended is usually 5 to 5 parts per 100 parts by weight of the polypropylene resin composition, the fibrous magnesium oxysulfate, and calcium carbonate.
10 parts by weight is sufficient. If the amount is less than 5 parts by weight, no improvement in impact strength may be observed, and if the amount is more than 10 parts by weight, the rigidity of the molded product made from this polypropylene resin composition may deteriorate, especially at high temperatures. There may be a significant decrease in the rigidity of the molded product, and there may be a significant decrease in the hardness of the surface of the molded product. In addition to the above-mentioned components, the polypropylene resin composition of the present invention may optionally contain antioxidants, flame retardants,
It may contain additives such as ultraviolet absorbers, antistatic agents, lubricants, mold release agents, and colorants. It goes without saying that the amount of this additive to be blended is a value that does not impair the mechanical properties, surface appearance, etc. of the molded article made of this polypropylene resin composition. The polypropylene resin composition of the present invention includes the polypropylene resin, the fibrous magnesium oxysulfate, the calcium carbonate, optionally calcium oxide or a calcium oxide-containing material,
The above-mentioned silane coupling agent, modified polyolefin, elastomer, and various additives are blended in a predetermined ratio, and sufficiently uniformly kneaded by a combination of dry mixing and melt mixing, a multistage melt mixing method, a simple melt mixing method, etc. This can be obtained by The kneading operation can be carried out using, for example, an open roll, a Banbury mixer, a V-type blender, a single-screw extruder, a twin-screw extruder, a co-kneader extruder, a multi-screw extruder, or the like. The polypropylene resin composition thus obtained can be molded into various molded products by various processing methods such as injection molding, extrusion molding, blow molding, compression molding, vacuum molding, pressure molding, lamination molding, roll processing, and stretching processing. Ru. The resulting molded product has good mechanical properties such as impact strength and rigidity, and has a very good surface condition, with very little warpage or deformation, so this polypropylene resin composition is used as an industrial material for automobiles, electrical fields, etc. It is extremely useful as a material in this field. [Effects of the Invention] According to the present invention, (1) Compared to conventional polypropylene resin compositions containing inorganic fillers, if the amount of inorganic fillers blended is the same, the rigidity and/or impact strength is improved. (2) Compared to conventional polypropylene resin compositions containing inorganic fillers, if the impact strength is the same, it has greater rigidity; (3) Compared to conventional polypropylene resin compositions containing inorganic fillers, Compared to conventional polypropylene resin compositions, polypropylene has higher impact strength if the rigidity is the same, and (4) polypropylene that achieves the above (1) to (3) and also provides a beautiful surface appearance of molded products. A resin composition can be provided. This polypropylene resin composition is based on the above (1) to (4).
Due to its properties, it can be processed into molded products that have greater rigidity and/or impact strength than conventional products, and have a beautiful appearance, depending on the characteristics required in the automobile-related technical field or light electrical technology-related technical field. Furthermore, when calcium oxide or a calcium oxide-containing material is blended into this polypropylene resin composition, silver streaks do not occur on the surface of the molded product even when molded at high temperatures, and a good surface appearance can be maintained. Such characteristics of this polypropylene resin composition are first achieved by blending a polypropylene resin, a specific fibrous magnesium oxysulfate, and a specific calcium carbonate in a limited blending ratio. [Example] Next, the present invention will be described in more detail by showing Examples and Comparative Examples. (Examples 1 to 6 Comparative Examples 1 to 6) Ethylene-propylene block copolymers of types and amounts shown in Tables 1 to 7 and
A fibrous filler of the type and amount shown in Table 7 and an inorganic filler having an average particle diameter shown in Tables 1 to 7 and an amount shown in Table 1 to Table 7 are combined into V After thorough mixing using a mold blender, the mixture was melt-mixed using a twin-screw kneading extruder at 200°C to obtain pellets. This pellet was injection molded at 200°C to prepare a test piece. The following physical properties were measured using the test piece. The results are shown in Tables 1 to 7. {Izot impact strength} Measured in accordance with ASTM D256 (notched). {Falling impact strength} Measured in accordance with JIS K7211. Strike radius 1/4
Inch, conical pedestal 50φ {Bending modulus of elasticity} Measured in accordance with ASTM D790. {Surface appearance} Injection molded at a molding temperature of 200℃ and a mold temperature of 50℃.
The surface roughness of a flat plate measuring 140 x 140 x 3 mm was visually observed and evaluated. (Examples 7 and 8 Comparative Example 7) The pellets obtained in Example 2 and calcium oxide master pellets were blended in the amounts shown in Table 9, and the pellets were injected at various heating temperatures shown in Table 9. A test piece was prepared by molding, and its surface appearance was visually observed and evaluated. The results are shown in Table 9.

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[Table] {Consideration} In Table 1, Comparative Examples 1 and 2, Example 2,
Compare 5 and 6. Fillers were added as shown in Comparative Example 1 and Comparative Example 2.
If 30% by weight is added, the impact strength will be significantly lowered, but in Example 1, although the filler was added in the same amount as in Comparative Examples 1 and 2, the rigidity (bending strength) The impact strength was significantly increased while the elastic modulus (evaluated by elastic modulus) remained almost the same as that of the comparative example. In Example 6, the rigidity was significantly increased while maintaining almost the same impact strength as in the comparative example. In Example 5, both rigidity and impact strength are greater than those in Comparative Examples 1 and 2. In Table 2, Example 1 and Comparative Example 3 are compared. In either case, the amount of filler added is
It is 20% by weight. In Example 1, compared to Comparative Example 3, a polypropylene resin composition with greater rigidity and impact strength was obtained. In any of Tables 3 to 5, the polypropylene resin composition of the present invention having the same stiffness as the comparative example has a higher impact strength than the comparative example. As shown in Table 6, although the composition is the same, the polypropylene resin composition in which the particle size of calcium carbonate is within the range of the present invention has a stiffness comparable to that of the comparative example. , impact strength has been significantly improved. As shown in Table 7, even if the particle size of the inorganic filler is within the range of the present invention, when the combined fibrous filler is within the range of the present invention, the rigidity and impact strength are significantly improved. .

Claims (1)

[Claims] 1 Polypropylene resin 42-92% by weight, average fiber diameter 0.1-2μ, and aspect ratio 20-20
60% by weight of fibrous magnesium oxysulfate and 5% to 40% by weight of calcium carbonate having an average particle diameter of 0.1 to 0.8μ.