JPS6144099B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a molding polypropylene resin composition in which antistatic properties are improved by blending an antistatic agent into inorganic filler-reinforced polypropylene. Inorganic filler-reinforced polypropylene is widely used in the automotive parts and home appliance fields due to its excellent rigidity, heat resistance, and dimensional stability, but because it is electrostatically charged, it easily attracts dust in the air and gets dirty, so improvements are desperately needed. It had been. As a method for improving the antistatic properties of polypropylene, it has been known to incorporate an antistatic agent into the polypropylene. However, when this method is applied to inorganic filler-reinforced polypropylene, the antistatic agent is adsorbed by the inorganic filler, so the expected antistatic effect is not achieved, and the antistatic effect is not practical for inorganic filler-reinforced polypropylene. At present, there is no way to impart preventive properties. The present inventors investigated a method of imparting antistatic properties to inorganic filler-reinforced polypropylene, and found that inorganic filler-reinforced polypropylene, which is a well-kneaded mixture of polypropylene and an inorganic filler, was prepared by adding polypropylene and a specific antistatic property to the inorganic filler-reinforced polypropylene. When molded using a resin composition obtained by kneading 5 to 50 parts of resin (so-called masterbatch) in granular or powder form, it has an excellent antistatic effect. They discovered this and completed the present invention. The polypropylene resin composition A blended with an inorganic filler used in the present invention is a propylene homopolymer, a copolymer of propylene and an α-olefin such as ethylene or butylene of 20 wt% or less, or a low-density polyethylene, a high-density Talc, calcium carbonate, barium sulfate, etc. are added to polyethylene, ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, etc. alone or in combination of 30% or more by weight.
Aluminum hydroxide, gypsum, dawsonite, simgon, radiolite, celite, novasite,
Asbestos, alumina, attapulgite, kaolin clay, volcanic ash, silica, wollastonite, diatomaceous earth, magnesium oxide, magnesium carbonate, feldspar powder, vermiculite, biotite, chromite, black slag, slag, obsidian, magnesium silicate It is a polypropylene compounded with an inorganic filler, which contains 5 to 50% by weight of the following alone or in combination of two or more. Further, an antioxidant, an ultraviolet inhibitor, a lubricant, a pigment, an antistatic agent, etc. can be added to the inorganic filler-containing polypropylene as necessary. As for the combination,
It is necessary to knead the inorganic filler and polypropylene. One of the antistatic agents used in the present invention has the general formula (However, R ¹ is an aliphatic hydrocarbon residue having 8 to 18 carbon atoms, and m and n are integers of 1 to 5 and may be the same or different.) ethyl)
It is an amine. Examples include N,N-bis(2-hydroxyethyl)stearylamine and N,N-bis(2-hydroxyethyl)octylamine. The second antistatic agent used in the present invention has the general formula (However, R ² is a saturated or unsaturated aliphatic hydrocarbon residue having 12 to 18 carbon atoms, and X is a hydrogen atom or

It is a group represented by the formula: R ³ is a saturated or unsaturated aliphatic hydrocarbon residue having 12 to 18 carbon atoms. ) is a fatty acid glyceride represented by For example, stearic acid monoglyceride, linoleic acid monoglyceride, behenic acid monoglyceride,
Examples include fatty acid glycerides such as ricinolenic acid monoglyceride, stearic acid diglyceride, linoleic acid diglyceride, behenic acid diglyceride, and ricinolenic acid diglyceride. In the present invention, it is necessary to use the above-mentioned first and second antistatic agents together. Resin composition B containing an antistatic agent used in the present invention refers to a propylene homopolymer, a copolymer of propylene and 20% by weight or less of α-olefin such as ethylene or butylene, or a copolymer of these with polyethylene or ethylene-propylene. 100 parts by weight of a polymer, ethylene-propylene-diene terpolymer, etc., alone or in a mixture of up to 30% by weight of two or more, and one or two of the above N,N-bis(polyoxyethyl)amines. more than that
This is a resin composition (antistatic agent masterbatch) comprising 0.5 to 5 parts by weight and 1 to 10 parts by weight of one or more of the above fatty acid glycerides. Particularly preferably, 2 to 8 parts by weight of stearic acid monoglyceride, oleic acid monoglyceride, behenic acid monoglyceride, or a mixture thereof and 1 part by weight of N,N-bis(2-hydroxyethyl)stearylamine are added to 100 parts by weight of polypropylene.
It is a resin composition consisting of ~3 parts by weight. The polypropylene used for this masterbatch is not only the same as that used for the inorganic filler-containing polypropylene, but also different types can be used. Further, antioxidants, ultraviolet inhibitors, lubricants, pigments, etc. can be added to this resin composition as necessary. The antistatic resin composition of the present invention is prepared by uniformly mixing the powder or granules of the inorganic filler-containing polypropylene resin composition A and the powder or granules of the antistatic agent masterbatch B using a commonly used blender. can be obtained. In this case, it is essential that both of them are mixed together in the form of powder or granules, and if they are kneaded to form a composition, the object of the present invention cannot be achieved. The mixing ratio of the inorganic filler-containing polypropylene A and the antistatic agent masterbatch B is preferably 5 to 30 parts by weight of the masterbatch per 100 parts by weight of the inorganic filler-containing polypropylene. If the amount is less than 5 parts by weight, the antistatic effect will not be sufficient. If the amount exceeds 30 parts by weight, physical properties such as rigidity and heat resistance will deteriorate. It is not clear why antistatic properties appear when antistatic agents are masterbatched, but surfactants are generally used in antistatic agents, which have the property of being easily adsorbed by inorganic fillers. Therefore, it is estimated as follows. That is, when an antistatic agent is simply kneaded into polypropylene together with a filler, the resin undergoes thermal history twice: during kneading and during molding. In this process, most of the antistatic agent is adsorbed by the inorganic filler, and only a small amount of the antistatic agent emerges on the surface of the molded product, so that no antistatic effect is exhibited. The surface of a molded product obtained by molding the resin composition of the present invention has significantly reduced chargeability compared to conventional products. Hereinafter, the present invention will be specifically explained with reference to Examples. Example 1 80 parts by weight of an ethylene-propylene block copolymer having an MI of 8 and containing 10 wt% ethylene, 10 parts by weight of talc, 10 parts by weight of barium sulfate, 0.1 part by weight of BHT as an antioxidant, 0.1 part by weight of calcium stearate, Add 0.05 parts by weight of n-octadecyl-3 (4'-hydroxy-3'-5'-di-tertiarybutylphenol) propionate, mix for 5 to 10 minutes with a Henschel mixer, and mix at 200°C.
Extrusion pellets of inorganic filler-containing polypropylene resin composition A were prepared using a vented screw extruder. For antistatic masterbatch B, 100 parts by weight of the above ethylene-propylene block copolymer was added to

[Formula] 4 Weight part

[Formula] 2 parts by weight, 0.1 parts by weight of 2,6-di-t-butyl-p-cresol as an antioxidant, 0.1 parts by weight of calcium stearate, n-octadecyl-3-(4'hydroxy-3'-
Add 0.05 part by weight of 5'-ditase butylphenol) propionate, mix for 5 to 10 minutes using a Henschel mixer, and use a vented screw extruder at a temperature of 200°C to produce extruded pellets (masterbatch). did. 10 parts by weight of an antistatic agent masterbatch was thoroughly mixed with 90 parts by weight of the inorganic filler-containing polypropylene obtained above in a blender to obtain a resin composition of the present invention. Resin temperature 230℃, injection pressure 1000
An injection molding sheet with a thickness of 2 mm was produced by injection molding under conditions of Kg/cm ² and a total cycle of 30 seconds. Since the chargeability of the sheet varies greatly for a while after molding, the surface resistivity and honest meter half-life of the injected sheet were measured on the third day after molding, and an ash adhesion test was also conducted. The results are shown in Table-1.

[Table] Comparative Example 1 The same polypropylene used in Example 1 was filled with 9wt% talc and 9wt% barium sulfate, mixed with the same antistatic agent and antioxidant as used in Example 1, and mixed with a Henschel mixer. Mix for 5-10 minutes and bring to temperature
Pellets of inorganic filler-reinforced polypropylene were made using a vented screw extruder at 200°C. This product was formed into an in-die extension sheet under the same conditions as in Example 1, and on the third day, surface resistivity, honest meter half-life, and ash adhesion tests were conducted. The results are shown in Table-2.

[Table] Example 2 Inorganic filled polypropylene A prepared in the same manner as in Example 1 and antistatic agent masterbatch B were mixed in a blender at a polymerization ratio of 8:2.
A resin composition of the present invention was obtained. The results of surface resistivity, honest meter half-life, and ash adhesion test on the 3rd day after molding of an in-die extension sheet produced using this material in the same manner as in Example 1 are shown below.
Shown in 3.

【table】

Claims (1)

[Claims] 1. 100 parts by weight of polypropylene and 5 to 5 parts by weight of inorganic filler
100 parts by weight of polypropylene and general formula (However, R ¹ is an aliphatic hydrocarbon residue having 8 to 18 carbon atoms, and m and n are integers of 1 to 5 and may be the same or different from each other.) Antistatic agent 0.5 to 5 weight by weight part and general formula (However, R ² is a saturated or unsaturated aliphatic hydrocarbon residue having 12 to 18 carbon atoms, X is a hydrogen atom or a group represented by the formula, and R ³ is a saturated or unsaturated aliphatic hydrocarbon residue having 12 to 18 carbon atoms. or an unsaturated aliphatic hydrocarbon residue.) Mix 5 to 50 parts by weight of resin composition B in the form of granules or powder, which is obtained by kneading 1 to 10 parts by weight of an antistatic agent represented by Antistatic resin composition.