JPH01178542A - Plastic sheet filled with mica powder and its production - Google Patents

Abstract

PURPOSE:To obtain inexpensively the title plastic sheet by a one-stage sheeting process, by melt-kneading a specified composition comprising polypropylene, polyethylene and a mica powder, extruding the melt into a sheet and cooling it. CONSTITUTION:Polypropylene (A) comprising at least 20wt.% granular polypropylene is mixed with 3-25wt.% polyethylene (B) and 10-60wt.% mica powder (C) of a weight-average flake diameter of 15-500mum and a bulk density >=0.15, provided that they are selected so that the melt flow rate of the granular polypropylene and/or the polyethylene as measured under conditions of a load of 2,160g and 230 deg.C is larger than that of the polypropylene as measured under the same conditions. A plastic sheet filled with the mica powder is obtained by melt-kneading and extruding the obtained composition into a sheet and cooling the obtained sheet.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a mica powder-filled plastic sheet that is inexpensive, has little compositional unevenness, and has high rigidity, and is produced using a commonly used extruder. Regarding. Utilizing its excellent rigidity, the uninvented sheet is widely used in fields such as civil engineering and construction materials, electrical equipment, automobile parts, and miscellaneous goods.

[Conventional technology]

The superior performance of plastic sheet materials containing mica powder is demonstrated by, for example, A, D, 0sborn.
eand F, W, Maine, SP I 29
th, Ann, Tech, Conf,, 24-
E (1974), JP-A-54-162743, JP-A-5
No. 7-154994. However, it is manufactured using a process commonly used in the past, which involves melting and kneading mica powder and plastic to form pellets, feeding the pellets again into an extruder, extruding them into a 7-sheet shape, and cooling the sheets. The problem with mica powder-filled plastic sheets is that they are expensive to manufacture. Furthermore, the plastic sheet filled with mica powder produced by this process has a problem in that the flake-shaped mica powder is destroyed by the two-step melt mixing process in the extruder, resulting in a decrease in the mechanical properties of the resulting sheet. 0 In order to solve these problems, it is conceivable to use a process in which mica powder and plastic pellets are supplied to an extruder, extruded into a sheet while being melted and kneaded by the extruder, and the sheet is cooled. However, mica-filled plastic sheets produced using this process have large variations in the mixing ratio of mica powder in the length and width directions of the sheet, and the dispersibility of mica powder into plastic is poor, making it difficult to put into practical use. There wasn't.

[Problems to be solved by the present invention]

The purpose of the present invention is to produce an inexpensive mica powder-filled plastic sheet without sacrificing the excellent properties of the mica powder-filled plastic sheet.More specifically, mica powder and plastic pellets are fed into an extruder. In the process of extruding into a sheet while melt-kneading with an extruder (hereinafter referred to as the one-stage sheeting process), problems such as variations in the mixing ratio of mica powder within the sheet and poor dispersion of mica powder are solved. [Means for Solving the Problems] The present inventors have conducted various studies to solve the above problems, and as a result, the present inventors have developed mica powder and polypropylene pellets (hereinafter referred to as PP). pellets) and polyethylene pellets (hereinafter referred to as P
It was discovered that by using a composition consisting of E pellets (abbreviated as E-pellets) and further adding granular polypropylene, a sheet with excellent performance can be obtained at low cost in a one-stage sheet forming process, and in order to complete the present invention. It's arrived.

The present invention has as essential components polypropylene, polyethylene, and mica powder, of which 20% by weight or more is granular polypropylene, and the blending ratio of the polyethylene is 3% by weight or more and 25% by weight or less, and granular polypropylene and/or Polyethylene melt 70-rate is 230℃
, when measured under the load condition of 2161, is higher than the melt flow rate of polypropylene measured under the same conditions, and further, the mica powder has a weight average flake diameter of 15 μm or more and 500 μm or less, and a bulk specific gravity of 0.15 or more. The blending rate is 1
A plastic sheet made of a compound with a content of 0% by weight or more and 60% by weight or less, and a method for producing a plastic sheet by a so-called one-stage sheeting process, in which the compound is extruded into a sheet shape while melt-kneading and cooled. It is.

The polypropylene used in the present invention is not particularly limited, but has a melt flow rate of 0.2r/lomi.
For extrusion, blow molding, etc. of n to 5r/10ml are preferably used, and modified, modified, and blended products of these may be used depending on the purpose.

In addition, the polypropylene component used in the present invention has a particle size of 100 to 1200 μm and a temperature of 230°C.
It is necessary that 20% by weight or more of granular polypropylene whose melt flow rate measured under a load of 2161 is higher than that of polypropylene measured under the same conditions is required. Here, granular means average particle size of 100 to 12001J.
Refers to particles having a weight of 98 or more and a bulk specific gravity of 0.5 or more. If the melt flow rate of the granular polypropylene decreases, the dispersibility and surface condition of mica in the sheet formed by melt-kneading in an extruder will be poor, and the compositional unevenness of mica will become large. Desirably, the range is from 30 to 90% by weight. In the present invention, polypropylene and polyethylene are essential components as resin components, and the polyethylene used in the present invention has a melt flow rate of 70-rate measured under the conditions of a temperature of 230°C and a load of 2161. rate or higher, and the amount blended in the resin component must be 3% by weight or more and 25% by weight or less. Melt Flow Ray of Polystyrene)
If the melt flow rate is lower than the melt flow rate of Kaho IJ 7'lopyrene, the dispersibility and surface condition of mica in the sheet formed by melt-kneading in an extruder will be poor, and clouds will not be sufficient, making it impossible to achieve the purpose of the present invention. do not have. Desirably, the range is from 5 to 20 degrees.

The mica powder used in the present invention can be appropriately selected from phlogopite (a govite), muscovite (muscovite), synthetic mica, etc., but these have a weight average flake diameter of 15 μm or more and 500 μm or less. Become. - If the weight average flake diameter is 500 μm or more, the flakes do not stick well to the extrusion chamber, and the production rate decreases due to variations in the amount of mica blended or due to thicker mica, making it difficult to form into a sheet. Preferably, mica powder has a bulk specific gravity of 0.2 or more. These mica powders contain 10
Weight - Over 60 weight! The low-strength effect is not sufficient, and 60% by weight≠=≠# is difficult to melt and knead in an extruder, making it impossible to form it into a sheet. Preferably 15
The range of 0% by weight to 50% by weight is preferred.

Antioxidants, coupling agents, mold release agents,
Adding coloring agents, flame retardants, etc. can only be done laterally.

The plastic sheet used in the present invention has a thickness of 0.5~
It refers to a sheet-like product in the range of 5III, and the equipment for producing the sheet includes a general-purpose single-screw extruder, twin-screw extruder, etc. for melt mixing, and a full-flight screw, a screw for mixing. Examples include dalmage screw and double flight screw. In addition, methods for feeding materials to the extruder include coil feeders, twin-screw feeders,
The following methods are unsuccessful: a quantitative feeding method in which each or the entire composition is mixed in a tumbler or the like using an electromagnetic feeder, a natural feed method in which the entire amount of the composition is mixed in a tumbler, and the mixture is fed into an extruder hopper. Forming into a sheet is carried out using a general-purpose T-die, sheet take-off machine, and the like.

However, the present invention is not limited to the above-mentioned apparatus, and can melt and cross-wire a plastic sheet with a thickness of 0.1 to 5 cm mixed with mica powder in a single melting process! ! 8! Any device that can be used is fine.

The present invention will be explained below with reference to examples, but the present invention is not limited to these examples.

Phlogopite (trade name Sugilite Mica) 15mid%, 0,
8 t/l 0m1n melt 7ci-L/-) was converted into sulfolipropylene pellets (hereinafter abbreviated as Pk') 6
7-layer ff1%, 1.5P/10m1n 71k
) 7 C1-ray) Granular polypyrene (hereinafter abbreviated as granular PP) with 15% and 1.5% in Tif7
3% by weight of high-density polyethylene pellets (hereinafter abbreviated as PE) with a melt 70-rate of f/l 0ml1n
were each fed in a fixed amount using a feeder, melted and kneaded using a 65 dia. A sheet was formed. As a result of measuring the following four items on the obtained sheet, the surface condition, dispersibility of mica, variation in mica mixing ratio, and specific elastic modulus were all good, and the results are summarized in Table 1.

Surface condition: Surface roughness observed with the naked eye.

Dispersibility of mica, small pieces were cut from 10 locations each in the extrusion direction and the direction of ejection, and were made into a thin plate with a thickness of approximately 0.2 cm using a flat plate hot press, and the dispersibility of mica was determined with the naked eye.

Variation in mica mixing ratio: Cut out small pieces from 20 locations each in the extrusion direction and width direction, measure the entire mica mixing ratio using the scorching heat loss method, and measure the variation from the average value.

Specific modulus: A S T M D from the extrusion direction of the sheet
The bending elastic modulus is measured in accordance with 790, and the specific elastic modulus is calculated by dividing by the specific gravity of the sheet.

Example 2 Phlogopite having the same particle size and bulk specific gravity as Example 1 was
The same equipment was used in the same manner as in Example 1, except that 40% by weight of PP having the same melt a-rate as in Example 1, 25% by weight of granular PP, and 5% by weight of PE were used. A sheet with a thickness of 2 squares was formed using the following method. The obtained sheet was subjected to the same performance evaluation as in Example 1, and as a result, the surface condition, mica dispersibility, mica mixing ratio variation, and specific elastic modulus were all good, and the results are summarized in Table 1.

Example 3 Phlogopite having the same particle size and bulk specific gravity as Example 1 was
0 weight t%, 45 weight t* of granulated PP having the same melt flow rate as Example 1, and 5 weight fj 1% of PE were used in the same manner as in Example 1, using the same equipment, to a thickness of 2. A sheet was formed. The obtained sheet was evaluated for performance in the same manner as in Example 1, and the results showed that the surface condition, mica dispersibility,
Both the mica mixing ratio variation 2 and the specific elastic modulus were good, and the results are summarized in Table 1.

Example 4 1 PK having the same melt flow rate as Example 2
A sheet having a thickness of 2101 mm was molded using the same composition, method, and same apparatus as in Example 2, except that 5% by weight and 30% by weight of PP were used. As a result of performing the same performance evaluation as in Example 1 on the obtained sheet, the surface condition, mica dispersibility -
Both the variation in the mica mixing ratio and the specific elastic modulus were good, and the results are summarized in Table 1.

Example 5 The same composition and method as in Example 2 were used, except that muscovite (K, manufactured by Kuraray, trade name, Clarite Mica) having an average particle size of 18 μm and a bulk specific gravity of 0.20 was used. A sheet with a thickness of 2 wm was molded using the apparatus.

As a result of performing the same performance evaluation as in Example 1 on the obtained sheet, it was found that the surface condition, mica dispersibility, mica mixing ratio variation, and specific elastic modulus were all good, and the results are summarized in Table 1. .

Example 6 Example 2 except that phlogopite (trade name Sugilite Mica) having an average particle size of 280 μm and a bulk specific gravity of 0.35 was used.
A sheet having the same composition, the same method, and the same apparatus was used to form a sheet with a thickness of 2 times. The obtained sheet was subjected to performance evaluation in the same manner as in Example 1. As a result, the surface condition, mica dispersibility, mica mixing ratio variation, and specific elastic modulus were all good, and the results are summarized in Table 1. , Comparative Example 1 Phlogopite having the same particle size and bulk specific gravity as in Example 1 was
Except for using 77% by weight of PP having the same melt flow rate as in Example 1, a sheet having the same composition as in Example 1, the same method, and the same apparatus was used to form a sheet with a thickness of 2 mm. When the obtained sheet was subjected to performance evaluation similar to that in Example 1, the dispersibility of mica, the surface condition, and the variation in the mixing ratio of mica were good, but the specific elastic modulus was low. The results are shown in Table 1.

Comparative Example 2 Phlogopite having the same particle size and bulk specific gravity as Example 3 was
An attempt was made to form a sheet using the same equipment as in Example 3, using the same composition and the same method as in Example 3, except that 25% by weight of granulated PP having the same melt flow rate as Example 3 was used, but the kneading failed. It was difficult to make it into a sheet. The results are shown in Table 1.

Comparative Example 3 PP having the same melt flow rate as Example 2 was
5% by weight, same composition as Example 2 except that PE is not blended,
A 2 m thick sheet was formed in the same manner and using the same equipment. The performance evaluation of the obtained sheet was performed in the same manner as in Example 1, and the specific elastic modulus was the same as in Example 2, which was rare; The variation was about twice as bad as in Example 2. The results are shown in Table 1.

Comparative Example 4 PP having the same melt flow rate as Example 2 was
A sheet having a thickness of 2fi was molded using the same composition, the same method, and the same equipment as in Example 2, except that 0% by weight and 25% by weight of PE were used. When the obtained sheet was subjected to the same performance evaluation as in Example 1, the surface condition and the variation in mica mixing ratio were good, but the dispersibility of mica was poor and the specific elastic modulus was low. The results are shown in Table 1.

Comparative Example 5 Melt flow rate 0.6 f/10m1n (7)
A sheet having a thickness of 2 m11 was molded using the same composition, method, and same equipment as in Example 2, except that 5 weights of PE were used more. When the obtained sheet was evaluated for performance in the same manner as in Example 1, the specific elastic modulus was good, but the dispersibility of mica was poor, the surface condition was poor, and the variation in mica mixing ratio was poor. The results are shown in Table 1.

Comparative Example 6 A sheet with a thickness of 2 days was molded using the same composition, method, and same apparatus as in Example 2, except that 25 weight more of the granules pp having a melt flow rate of Q and 6P of 710 min were used. When the obtained sheet was evaluated in the same manner as in Example 1, the specific elastic modulus was good, but the dispersibility of mica was poor, the surface condition was poor, and the variation in mica mixing ratio was poor. The results are shown in Table IK.

Comparative Example 7 PP having the same melt flow rate as Example 2 was
A sheet having a thickness of 2 mm was molded using the same composition, the same method, and the same apparatus as in Example 2, except that the 5 weight - 1 granule PP was not used. When the obtained sheet was evaluated in the same manner as in Example 1, the specific elastic modulus was good, but since granular PP was not used, the variation in the mixing ratio of mica was very poor, and the dispersibility of mica and surface condition were poor. was also inferior. The results are shown in Table 1.

Comparative Example 8 A sheet with a thickness of 2 m was molded using the same composition, the same method, and the same equipment as in Example 5, except that muscovite (prototype) having an average particle size of 10 μm and a bulk specific gravity of 0.20 was used. . The obtained sheet was evaluated in the same manner as in Example 1, and although the surface condition and the variation in mica mixing ratio were good, the average particle size of mica was small, so the dispersibility of mica was poor, and the dispersibility of mica was poor compared to The elastic modulus was poor. The results are shown in Table 1.

Comparative Example 9 A second-thick sheet was produced using the same composition, method, and same equipment as in Example 6, except that phlogopite (trade name Sugilite Mica) having an average particle size of 650 μm and a bulk specific gravity of 035 was used. Molded. When the obtained sheet was evaluated in the same manner as in Example 1, it was found that mica dispersibility, mica mixing ratio variation, and specific elastic modulus were good, but the surface condition was very poor due to the large average particle size of mica. It was bad. Table 1 shows the results.
Shown below.

Comparative Example 10 The same composition as in Example 2 was fed quantitatively using a feeder, and 659 was equipped with a full-flight screw.
The mixture was melt-kneaded using a φ extruder to produce pellets containing 30% by weight of mica. After tamping the resulting pellets, a full-flight screw was installed.
Re-melted and mixed in a 5mφ extruded rock, T-
It was extruded into a sheet using a die to form a sheet with a thickness of 2fi. When the obtained sheet was evaluated in the same manner as in Example 1, it was found that the mica dispersibility, surface condition, and mica mixing ratio variation were good, but the specific elastic modulus was inferior compared to the example. At the same time, the melting and crossing is performed twice, which is disadvantageous in terms of cost.

The results are shown in Table 1.

[Effects of the Invention] According to the present invention, it is possible to provide a mica powder-filled plastic sheet that is cheaper than using a one-stage sheeting process without impairing the excellent properties of the mica powder-filled composition.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Scope of Claims] 1. The essential components are polypropylene, polyethylene, and mica powder, of which 20% by weight or more is granular polypropylene, and the blending ratio of the polyethylene is 3% by weight or more25
% by weight or less, and the melt flow rate of granular polypropylene and/or polyethylene is 230°C, 21
When measured under a load of 60 g, the melt flow rate is higher than that of polypropylene measured under the same conditions, and the mica powder has a weight average flake diameter of 15 μm or more.
A plastic sheet made of a compound having a bulk specific gravity of 0.00 μm or less, a bulk specific gravity of 0.15 or more, and a blending ratio of 10% by weight or more and 60% by weight or less. 2. A method for producing a plastic sheet, which comprises extruding the compound according to claim 1 into a sheet while melt-kneading and cooling the mixture.