JPH03185038A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide the subject composition having high elastic modulus and inner loss and useful for producing lightweight molded products by incorporating in a specific ratio inorganic fillers including mica having a specific weight- average flake diameter and a specified weight-average aspect ratio into the composition. CONSTITUTION:The objective composition comprises a polypropylene resin and <=20wt.% of inorganic fillers including 3-15wt.% of mica (white mica) having a weight-average flake diameter of 10-700mum and a weight-average aspect ratio of >=10. The polypropylenic resin is e.g. a modified resin prepared by activating polypropylene resin and subsequently addition-reacting maleic acid, etc., to the activated polypropylene resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a polypropylene resin composition that is particularly suitable as a substitute for wood, pulp paper, etc. in applications where they are used to take advantage of their functional characteristics. relating to things.

[Conventional technology]

In applications where wood, pulp paper, etc. have traditionally been used, wood, pulp paper, etc. have problems such as low degree of freedom in design, long time required for molding and assembly, and large changes in physical properties in wet and dry conditions. In order to improve this problem, synthetic wood and synthetic paper have recently been developed.
A crystalline polyolefin resin composition has been reported as a material that has the functional properties of wood, pulp paper, etc., such as high elastic modulus and high internal loss (Japanese Patent Application Laid-Open No. 1639-1639).
(See Publication No. 45).

[Problem to be solved by the invention]

However, since the resin of the crystalline polyolefin resin combination acid is crystalline, the volumetric shrinkage rate before and after molding is large, and the molded product has whiskers. In order to improve this sink mark, it is necessary to use a large amount of inorganic filler, which poses a problem of increasing the density of the molded product.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition that has a high modulus of elasticity and a high internal loss, and is capable of producing lightweight molded products.

[Means to solve the problem]

According to the present invention, the above object is to use a polypropylene resin and a weight average flake diameter of 10 to 700μ, and t
Mica 3 to 15 with an average aspect ratio of 10 or more
Heavy! This is achieved by providing a polypropylene-based resin composition, which is a resin composition containing % as an essential component, and is characterized in that the content of photonic materials including mica is 20% by mass or less. .

There are no particular restrictions on the polypropylene resin used in the present invention, but it is preferably chemically modified to have an affinity for mica. Chemically modified polypropylene is a resin obtained by reacting polypropylene with an unsaturated compound, and such a resin is, for example, a peroxide.

Polypropylene resin activated by radial radiation etc.
It is produced by addition or graft polymerization of compounds such as maleic a, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, glycidyl methacrylate, glycidyl acrylate, and a silane coupling agent.

There are no particular restrictions on the mixing ratio of these compounds, but it is usually 0.03% by weight of the polypropylene resin.
~3 weight fly. Further, the polypropylene resin of the present invention may contain an aliphatic polyolefin copolymerized with an alkyl acrylate or an alkyl methacrylate, a copolymer component such as ethylene, and the like. Furthermore, the polypropylene resin of the present invention may be a mixture of chemically modified polypropylene and unmodified polypropylene.

The mica used in the present invention is white mica.

You can choose from a wide range of gold mica, synthetic mica, etc., and the weight average flake diameter is in the range of 10 to 700μ.
The average aspect ratio is 10 or more.

The elastic modulus of molded products with weight average flake diameters of less than 10μ and 700μ is extremely low. It is preferable to use mica having a weight average flake diameter of 15 to 500 μm and a weight average aspect ratio of 20 or more, especially 35 or more.

The weight-average aspect ratio of mica is a value determined using equation (1) from the weight-average flake diameter and weight-average flake thickness d measured by the following method.

Weight average aspect ratio = Amml
ar 5 of the mica powder plotted in Figure 4 and subjected to measurement
The opening L6G of the sieve through which 0 weight it% passes is determined, and the value is calculated from the obtained value using equation (2).

1' = l”inso (
2) What is the 1M average flake thickness d of the cased mica powder?

Water surface single particle removal method reported by C, E, Capes et al.
,E.

Capes and R.C., Coleman, In.
d, Eng, Chem, Fundam,, 12°12
4 (1973)) occupied by the flake at the water surface! This is a value calculated from equation (8), excluding R8.

Here, W is the weight of the flakes subjected to measurement, S is the area occupied by the flakes on the water surface, ρ is the specific gravity of the flakes, (1-ε
) is the occupancy rate when the flakes are in a close-packed state on the water surface, and when the flakes are mica, the value of ρ is 2.86f/-, and the value of (1-ε) is 2.86f/-. 0.9 is used in the calculation.

The blending ratio of mica is in the range of 3 to 15% by weight of the total composition, preferably in the range of 5 to 10% by weight.

If the blending ratio is less than 3% by weight, the elastic modulus and internal loss of the resulting molded product will decrease. Furthermore, if the blending ratio exceeds 15% by weight, the effect of reducing the weight of the molded product cannot be achieved.

The mica used in the present invention is preferably surface-treated with a silane coupling agent or the like so that it has good affinity for the matrix resin.

Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and the like. There are no particular restrictions on the blending ratio of these silane coupling cutters, but
Generally, it is 0.05 to 3 more by weight than the weight of mica. In addition, the surface alcohol treatment agent for silane coupling agent is:
Although mica may be used by surface-treating it in advance, it is also effective to directly add i- when melting and kneading the resin and mica.

In the present invention, glass fiber m is used in addition to mica.

Inorganic fillers such as wollastonite, talc, glass flakes, carbon fibers, graphite, calcium carbonate, barium sulfate, etc. can be added.

In particular, when the blending ratio of mica is less than 5%, the weight of the molded product can be reduced, but the elastic modulus and internal loss of the molded product are slightly inferior, so the modulus of elasticity and internal loss of the molded product must be lowered by 1e. Uedewolastonite, talc.

It is preferable to use graphite etc. together with mica. In that case, it is preferable that the blending ratio of the inorganic filler containing mica is less than 20% by weight of the total composition, and preferably less than 15% by weight. If the blending ratio exceeds 20 weight, the density of the resulting molded product becomes high, the weight reduction of the molded product is impaired, and the specific elastic modulus (elastic modulus/density) of the molded product decreases.

A blowing agent may be added to the composition of the present invention, and there are no particular restrictions on the type of blowing agent, such as azodicarbonamide, dinitrosopentamethylenetetramine,
Examples include chemical blowing agents such as nitrogen compounds such as p,p'-oxybis(benzenesulfonyl hydrazide) and carbonate compounds such as sodium bicarbonate, and physical blowing agents such as nitrogen and air.

These foaming agents may be used in combination with foaming aids such as calcium stearate and zinc diurate.

The expansion ratio is preferably in the range of 1.1 to 1.5 times. Rich,
Known additives such as colorants, plasticizers, lubricants, antioxidants, and copper damage inhibitors can also be added within a range that does not impair the performance of the resulting molded product.

The composition of the present invention is generally prepared by kneading each component in a single screw extruder, twin screw extruder, roll kneader, etc., and then using an injection molding machine, extrusion molding machine, compression molding machine, or calendar molding machine. etc., and molded into molded products of various shapes.

The molded product thus obtained has a density of 1. Oy/c
Small, less than rA, and elastic modulus of 2.0X10”dyn
The specific elastic modulus is high due to its large size of /7″ or more.

Since it has a high internal loss, it is useful for audio equipment such as speaker boxes and acoustic diaphragms.

[Effect]

According to the present invention, by adding a small amount of mica of a specific shape to polypropylene-based crushing, it is possible to obtain a molded product that not only has a modulus of elasticity of 1 and an internal loss but also has a 4i'Jt.

〔Example〕

EXAMPLES The present invention will be described below with reference to Examples, but these Examples do not limit the present invention in any way. In addition, the elastic modulus in Examples was evaluated by dynamic elastic modulus, and each physical property of the residue was measured by the following method.

Density: Measured 1-7 according to JIS K 7112A method and C method.

Expansion ratio: The value obtained by dividing the density of the foamed molded product by the density of the non-foamed molded product, as shown in Table 1. Ta.

Dynamic elastic modulus and internal loss: Toyo Baldwin Bipron L) L) [Using lEA, frequency 110 Hz
The dynamic elastic modulus (theft and internal loss (tan δ)) were measured and determined at 230°C.

Example 1 and Example 2 Melt flow rate (230°C, 21609) 159/
10 minutes of homopolypropylene with a weight average flake diameter of 2
Gold mica (Sujirite Mica 150-8% manufactured by Kurire Co., Ltd.) having a diameter of 30μ and an average b, xi aspect ratio of 65 was mixed in the proportions shown in Table 1, and melted and kneaded in an extruder to form pellets. I got it. A test piece was prepared from this pellet by an injection molding method, and the density, elastic modulus, and internal loss were measured using the test piece. The results are shown in Table 1.

Example 3 In Example 1, Uora stonite (Kemoritsu 1-
8-3, manufactured by Maruwa Biochemical (■)) in the proportions shown in Table 1, test pieces were prepared in the same manner as above, and the density, elastic modulus, and internal loss were measured. The results are shown in Table 1.

Example 4 In Example 1, a test piece was prepared in the same manner as in Example 1, except that white mica (-Kuraray #2) having a weight average flake diameter of 20 μ and an average aspect ratio of 40 was used instead of gold mica. , density, elastic modulus, and internal loss were measured.The results are shown in Table 1.

Example 5 In Example 1, low temperature impact resistant polypropylene (J-8
1sHK, manufactured by Ube Industries), average flake diameter is 20
A test piece was prepared in the same manner except that white mica and wollastonite, which have an average particle diameter of 40 μ and an average aspect ratio of 40, were mixed in the proportions shown in Table 1, and the density, elastic modulus, and internal loss were measured. Ta.

The results are shown in Table 1.

Example 6 In Example 1, homopolypropylene with a melt flow rate of 301/10 minutes, ethylene-ethyl acrylate copolymer (MB87n, manufactured by Nippon Unicar ■, copolymerization rate 4)
Test specimens were prepared in the same manner except that gold mica with an average aspect ratio of 90 was used, and the density, elastic modulus,
Internal loss was measured. The results are shown in Table 1.

Comparative Examples 1 to 5 Test pieces were prepared in the same manner as in Example 1, except that homopolypropylene with a melt flow rate of 152/10, white mica, and wollastonite were blended in the proportions shown in Table 1. The rate and internal loss were measured. Show the box.

Compared with the molded products made of the resin compositions obtained in Examples 1 to 6, the elastic modulus and specific elastic modulus were inferior.

Example 7 In Example 1, acrylic acid-modified polypropylene (Tonen Polypropylene C-SOOX) was substituted for homopolypropylene b.
A test piece was prepared in the same manner except that a sample (manufactured by Tonen Petrochemical Co., Ltd.) was used, and the density, elastic modulus, and internal loss were measured. The results are shown in Table 1.

Examples 8 and 9 In Example 7, blowing agent (GuiGlo P E 111
20, manufactured by Dainippon Seika ■) to 100 parts by weight of the resin composition, 91.1 times (Example 8)
), a test piece was prepared in the same manner except that it was foamed 1.4 times (Example 9), and the density 1 elastic modulus and internal loss were measured. The results are shown in Table 1.

Example 10 A test piece was prepared in the same manner as in Example 8 except that wollastonite was added as an inorganic filler, and the density 1 elastic modulus and internal loss were measured. The results are shown in Table 1.

Example 11 A test piece was prepared in the same manner as in Example 1O except that the expansion ratio was changed, and the density 1 elastic modulus and internal loss were measured. The results are shown in Table 1.

[Effects of the Invention] According to the present invention, a polypropylene resin composition for obtaining a molded article having a high elastic modulus and a high internal loss and having a light abrasion is provided.

Claims (1)

[Claims] Polypropylene resin and weight average flake diameter of 1
A resin composition containing 3 to 15% by weight of mica having a weight average aspect ratio of 0 to 700μ and a weight average aspect ratio of 10 or more, the content of inorganic fillers including mica being 20% by weight.
% by weight or less.