JPS61130359A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin comps. which has improved mechanical strength and impact strength and gives moldings having good surface appearance, by blending fibrous magnesium oxysulfate and calcium carbonate with a polypropylene resin. CONSTITUTION:42-92wt% polypropylene resin, 3-40wt% fibrous magnesium oxysulfate having an average fiber diameter of 0.1-2mu and an aspect ratio of 20-60 and 5-40wt% calcium carbonate are blended together. Polypropylene resins having a melt index of 2-30g/10min are preferred. Pref. calcium oxide is blended to give moldings having good surface appearance, even when the resin compsn. is molded at an elevated temp. calcium oxide is used in a quantity of 0.1-10pts.wt. based on that of the compsn.

Description

Detailed Description of the Invention [Industrial Application Field 1] This invention is reinforced with fibrous magnesium oxysulfate, which is a fibrous filler, and calcium carbonate, which is a non-fibrous filler. The present invention relates to a polypropylene resin composition that can be suitably used in the field.

[Prior art and its problems] Polyolefins reinforced with fillers are widely used as essential materials, mainly in the field of industrial materials, such as automobiles and light electrical appliances. In these fields, there is a demand for materials that have high rigidity and impact strength, have a beautiful surface appearance that does not deteriorate even when heated during molding, and are free from deformation such as warping.

However, in the past, various attempts have been made to improve polyolefin resins in order to meet the demands of the above-mentioned fields.
At present, there is still no material that satisfies all the properties required in the above field. For example, polyolefin resins reinforced with fibrous fillers, mainly glass fibers, show some significant improvements in strength and rigidity, but they also result in a decrease in impact strength, deterioration in the surface appearance of molded products, and sleigh,
It has the disadvantage of causing deformation, etc. Further, although polyolefin resins 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 was developed based on the above-mentioned 4.

That is, an object of the present invention is to provide a polypropylene resin composition that has improved mechanical strength and impact strength and has a beautiful surface appearance of molded products, and is suitable for use in the fields of automobiles, electricity, etc. .

In order to achieve the above object, the inventor conducted intensive research and found that a specific combination of fibrous magnesium oxysulfate having a specific average fiber diameter and aspect ratio and calcium carbonate having a specific average particle diameter was obtained. It has been discovered that when blended with polypropylene resin at a ratio of 1, it is possible to obtain a polypropylene resin composition that has high mechanical strength and impact strength, has a good surface appearance, is free from deformation, and can be molded into molded products with good dimensional stability. We have arrived at this invention.

[Means for solving the above problems] The outline of this invention for achieving the above object is as follows.

42 to 92% by weight of polypropylene resin, 3 to 40% by weight of fibrous magnesium oxide sulfate having an average edge diameter of 0.1 to 2μ and an aspect ratio of 20 to 60, and an average particle diameter of Q, 1 to 0.8% by weight of calcium carbonate, and 5 to 40% by weight of calcium carbonate.

The polypropylene resin used in this invention is not particularly limited as long as it is generally used as a molding material, etc. Therefore, it may be a propylene pomopolymer, a copolymer of propylene and an α-olefin, for example, a propylene-ethylene block copolymer, etc. Copolymer, propylene-ethylene random copolymer, etc. can be used. Among the various polypropylenes, crystalline polypropylene homopolymer,
A propylene-ethylene block copolymer and a propylene-ethylene random copolymer are preferred, and the polypropylene resin has a melt index (M
I) is preferably 2 to 30 g/10 minutes, and 3 to 30 g/10 minutes.
Particularly preferred is 20 g/10 minutes.

The a, II form magnesium oxysulfate in this invention has an average fiber diameter of 0.1 to 2, preferably 0.5 to 1, and an aspect ratio of 20 to 2.
60, preferably 30 to 5 degrees. It is. When the average fiber diameter is smaller than 0.1p,
The bulk specific gravity becomes too small, making it difficult to blend with other components, and even if it can be blended, the fibrous magnesium oxysulfate will have poor dispersion. Further, if the average fiber diameter exceeds 2 tiles and the aspect ratio exceeds 60, the surface appearance of a molded article formed using this polypropylene resin composition will be poor. When the average fiber diameter exceeds 2 tiles and the aspect ratio is less than 20, the improvement in rigidity of a molded article formed using this polypropylene resin composition is small.

The calcium carbonate in this invention has an average particle size of 0.
It is important that it is for 1 to 0.8 JL, preferably Q, 15 to 0°7. The average particle size of this calcium carbonate is 0. If it is less than 1, the dispersibility of calcium carbonate 9 will be poor. Moreover, when the average particle diameter exceeds 0.8 mm, 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.

One important point in this invention is that the polypropylene resin composition contains the polypropylene resin in an amount of 40 to 92% by weight, preferably 50 to 85% by weight, and the fibrous magnesium oxysulfate in an amount of 3 to 4 Oi%. , preferably 5 to 30% by weight, and the calcium carbonate is contained in an amount of 5 to 40% by weight, preferably 10 to 30% by weight.

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.

When the amount of calcium carbonate is less than 5% by weight,
Not only does the impact strength of the molded product of this polypropylene resin composition not improve, but it is also not effective in suppressing warping of the molded product, and if the amount of calcium carbonate exceeds 40% by weight, the impact strength of the molded product decreases. At the same time, the specific gravity of the polypropylene resin composition increases, which is disadvantageous in handling and molding.

The polypropylene resin composition of the present invention greatly improves mechanical properties such as impact strength, heat-resistant rigidity, etc. by blending the polypropylene resin, the fibrous magnesium oxysulfate, and the calcium carbonate in the specific blending ratio. The molded product has a beautiful surface appearance and is free from warping, deformation, etc. However, in order to maintain the good surface appearance of the molded product even when this polypropylene resin composition is molded at high temperatures, polypropylene It is preferable to blend calcium oxide or a calcium oxide-containing material into the resin composition.

The amount of the calcium oxide or calcium oxide-containing substance is usually 0.1 to 1 to 1,004 parts in total of the polypropylene resin composition, the fibrous magnesium oxysulfate, and the calcium JR acid. 1
1 part by weight, preferably 0.5 to 5 parts by weight. o, t-
When calcium oxide or a calcium oxide-containing substance is blended within the range of 0.00 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, and the appearance will be good. If the amount exceeds 10% by weight, no damage will occur.

The 1# impact strength of the polypropylene resin composition may decrease.

In addition, the calcium oxide or calcium oxide-containing material to be blended has an average particle size of 30 or less, especially 1 to
o, tp, the average particle diameter is preferably 30.
If it exceeds this amount, the surface appearance of the molded product of the polypropylene resin composition may deteriorate and the impact strength may decrease.

There is no particular restriction on the calcium oxide as long as it satisfies the above conditions, and the calcium oxide-containing material is one whose main component is calcium oxide.

An inorganic ceramic crystal composite obtained by reaction-sintering calcium oxide with an aluminum-magnesium-silica catalyst is preferable, and this inorganic ceramic crystal composite is available, for example, under the trade name "Aerox" (manufactured by Suzuhiro Chemical Co., Ltd.).

In this invention, in addition to the calcium oxide or the calcium oxide-containing substance, 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), and γ-glycidoxyprobyl. Trimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacrypyltrimethoxysilane, N-
Examples include β-(aminoethyl)-diamine, nopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyljethoxysilane.

Examples of the modified polyolefin include polyethylene, polypropylene, and ethylene-propylene copolymers modified with unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, chlorine, and vinylsilane. Examples of the unsaturated carboxylic acid used for the modification include acrylic acid, methacrylic acid, maleic acid, phyllic acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, and mesaconic acid.

Angelic acid, etc., and derivatives of the unsaturated carboxylic acid include acid anhydrides, esters, amides, imides,
There are metal salts, etc., such as macinic anhydride, itaconic anhydride, and citraconic anhydride.

Methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoethyl ester, acrylamide, maleic acid monoamide, maleimide, N-butylmaleimide, sodium acrylate,
Examples include 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-B-3),
Styrene-butadiene-styrene rubber (S-B-5)
, Styrene-isoprene-styrene rubber (S-I-5
), styrene-butadiene rubber (S-8)"f, olefin-based elastomers such as ethylene propylene rubber, ethylene propylene diene rubber, etc. are preferred, and styrene-butadiene rubber, ethylene propylene rubber, etc. are particularly preferred.

The blending amounts of the silane coupling agent and the modified polyolefin are as follows:
Normally, 0.1 to 5 parts by weight is sufficient for a total of 100 parts by weight of male magnesium oxysulfate and calcium carbonate, and if the amount is less than 0.1 part by weight, an improvement in mechanical strength can be seen. Furthermore, if the blending amount is more than 5 parts by weight, the same improvement in mechanical strength as described above will not be achieved, and there will be a disadvantage in terms of cost.

The blending amount of polyethylene and elastomer is a total of 100% of the polypropylene resin composition, the fibrous magnesium oxysulfate, and calcium carbonate.
Usually, the amount is 5 to 10 parts by weight based on part i. If the amount is less than 5 parts by weight, no improvement in impact strength may be observed, and if the amount is less than 5 parts by weight, If the amount is more than 1, the rigidity of the molded article made from this polypropylene resin composition, particularly at high temperatures, may be significantly lowered, and the surface hardness of the molded article may also be significantly lowered.

In addition to the above-mentioned components, the polypropylene resin composition of the present invention optionally contains an antioxidant and a flame retardant.

Ultraviolet absorber, antistatic agent (arsenal agent, lubricant, mold release agent 1) May contain additives such as colorants, the amount of these additives is as follows:
It goes without saying that this value is such that it does not impair the mechanical properties, surface appearance, etc. of a molded article made from this polypropylene resin composition.

The polypropylene resin composition of the present invention includes the polypropylene resin, the γi-woven fibrous magnesium oxysulfate, the calcium carbonate, optionally calcium oxide or a calcium oxide-containing material, the silane coupling agent, modified polyolefin, elastomer, and various It can be obtained by blending the additives in a predetermined proportion and kneading them sufficiently uniformly by a combination method of dry mixing and melt mixing, a multi-stage melt mixing method, a simple melt mixing method, etc. The kneading operation can be carried out using, for example, an open roll, a Pampari mixer, a V-type blender, an axle screw extruder, a two-wheel 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.

[Effect of the invention] A polypropylene resin composition according to the present invention.

The mechanical strength of the molded product, such as impact strength, rigidity, and heat resistance, can be significantly improved, the surface appearance can be improved, and warpage, deformation, etc. can be reduced. Furthermore, when calcium oxide or a calcium oxide-containing material is blended into this polypropylene resin composition, no silver streaks occur on the surface of the molded product even when molded at high temperatures, and a good surface appearance is maintained. be able to.

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 1] 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) Having an ethylene-propylene block co-7 polymer of the type and blending amount shown in Table 1, the f average fiber diameter and aspect ratio shown in the footnotes of Table 1, and After thoroughly mixing the fibrous filler having the composition shown in Table 1 and the non-woven filler having the average particle diameter shown in Table 1 and the amount shown in Table 1 in a V-type blender, - Pellets were obtained by melt mixing at 200° C. in a screw extruder.

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 Table 1.

(Izot impact strength) Measured in accordance with ASTM D256 (notched).

(Falling impact strength) Measured in accordance with JIS K7211. Strike radius 1
/4 inch, cone pedestal 50φ (flexural modulus) Measured in accordance with ASTM 0790.

(Surface appearance) 14 injection molded at a molding temperature of 200°C and a mold temperature of 50°C.
The surface roughness of the 0x140x3as flat plate was visually observed and evaluated.

(Example 7.8, Comparative Example 7) The pellets obtained in Example 2 and calcium oxide master pellets were blended in the amounts shown in Table 2, and the mixture was injected at various heating temperatures shown in Table 2. Create a test piece by molding,
The surface appearance was visually observed and evaluated.

The results are shown in Table 2.

In Table 1, especially from the results of Comparative Example 1 and Example 2, when the average particle diameter of the calcium carbonate to be blended is larger than 0.81L, the impact strength of the polypropylene resin composition decreases, and compared to Comparative Example 2. From the results of Example 2, when the average particle diameter of calcium carbonate is smaller than 0.1,
It is clear that the heat-resistant rigidity of the polypropylene resin composition is reduced. Furthermore, from the results of Comparative Example 3 and Example 5, the blending amount of fibrous magnesium oxysulfate was 3.
When the amount of calcium carbonate is less than 5% by weight, the heat resistance rigidity decreases, and from the results of Comparative Example 4 and Example 5.6, when the amount of calcium carbonate is less than 5% by weight, the impact strength of the polypropylene resin composition decreases. It is clear that this decreases. Also, from the results of Comparative Example 6, the average particle diameter of calcium carbonate was Q
, 3JJ, and the amount of the fibrous filler is 20% by weight, and even if the fibrous filler content t is 20% by weight, the average fiber diameter of the fibrous filler is outside the limited range of this invention. If so, the heat resistance rigidity and impact strength will decrease. Furthermore, comparative example 5
The results show that blending fillers other than calcium carbonate cannot improve impact strength. Comparing Examples 1 to 6 and Comparative Examples as a whole, the polypropylene resin composition of the present invention.

Heat resistant rigidity and! It can be seen that the impact strength is improved and the surface appearance of the molded product is always beautiful. In addition, although the value of impact strength is small in Example 4, when compared with Comparative Example 4, it can be seen that an improvement in impact strength of 1 degree has been achieved.

Further, from the results in Table 2, it can be seen that the blending of calcium oxide does not impair the appearance of the molded product even when molded at high temperature.

Claims (1)

[Claims] 42-92% by weight of polypropylene resin, 3-40% by weight of fibrous magnesium oxysulfate having an average fiber diameter of 0.1-2μ and an aspect ratio of 20-60, and an average particle diameter of 0.1-0. A polypropylene resin composition comprising 5 to 40% by weight of calcium carbonate having a particle diameter of .8μ.