JP2593902B2 - Plastic sheet filled with mica powder and method for producing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an inexpensive, low-moisture composition and high-rigidity mica powder-filled plastic sheet manufactured using a commonly used extruder. . The sheet of the present invention is widely used in the fields of civil engineering and construction materials, electric equipment, automobile parts, miscellaneous goods and the like by utilizing its excellent rigidity and the like.

[Conventional technology]

The excellent performance of plastic sheet materials containing mica powder is demonstrated, for example, by ADOsborne and FWMa.
ine, SPI 29th. Ann. Tech. Conf., 24-E (1974) and
54-162743 and JP-A-57-154994. However, it is manufactured by a process generally used conventionally, i.e., a process in which mica powder and plastic are melt-kneaded and once pelletized, the pellet is again supplied to an extruder, extruded into a sheet shape, and the sheet is cooled. The plastic sheet filled with mica powder has a problem in that its production cost is high. Further, the plastic sheet filled with mica powder produced by the process has a problem that the mica powder in the form of flakes is broken by a melt-kneading step in an extruder twice, and the mechanical properties of the obtained sheet are deteriorated. .

In order to solve these problems, it is conceivable to use a process in which the mica powder and the plastic pellet are supplied to an extruder, extruded into a sheet while being melt-kneaded by the extruder, and the sheet is cooled. However, the mica-filled plastic sheet produced by using this process has a large variation in the mixing ratio of the mica powder in the length and width directions of the sheet, and the dispersibility of the mica powder in the plastic is poor.
It was unbearable for practical use.

[Problems to be solved by the present invention]

An object of the present invention is to produce an inexpensive mica powder-filled plastic sheet without impairing the excellent properties of the mica powder-filled plastic sheet. More specifically, in a process in which mica powder and plastic pellets are supplied to an extruder and extruded into a sheet while being melt-kneaded by the extruder (hereinafter referred to as a one-stage sheet forming process), the mixing ratio of mica powder in a sheet is determined. SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems such as the dispersion of mica powder and poor dispersion of mica powder.

[Means for solving the problem]

The present inventors have conducted various studies in order to solve the above problems, and as a result, by using a composition comprising mica powder, granular polypropylene or a mixed polypropylene thereof and a polypropylene pellet, and polyethylene pellet, It was found that inexpensive sheets with excellent performance can be obtained by the single-stage sheeting process,
The present invention has been completed.

The present invention comprises granular polypropylene, polyethylene and mica powder as essential components, the blending ratio of the granular polypropylene is 20% by weight or more and 87% by weight or less, and the blending rate of polyethylene is 3% by weight or more and 20% by weight or less. Yes, and
The mica powder has a weight average flake diameter of 15 μm or more and 500 μm or less, a bulk specific gravity of 0.15 or more, and a compounding ratio of 10% to 60% by weight.
A plastic sheet comprising the following compound (hereinafter abbreviated as compound A), and having a melt flow rate of 0.2
55 g / 10 min of granular polypropylene and pelletized polypropylene, wherein at least 20% by weight of the components are granular polypropylene, polypropylene, polyethylene and mica powder as essential components.
% By weight to 87% by weight, the mixing ratio of polyethylene is 3% by weight to 20% by weight, and the melt flow rate of granular polypropylene and polyethylene is 230% by weight.
° C, when measured under the condition of a load of 2160 g, the melt flow rate of the pelletized polypropylene measured under the same conditions is greater than or equal to, and further, the mica powder has a weight average flake diameter
15 μm or more and 500 μm or less, bulk specific gravity of 0.15 or more, compounding ratio is 1
0% by weight or more and 60% by weight or less (hereinafter referred to as B
This is a method for producing a plastic sheet by a so-called one-stage sheet forming process, in which the compound A or B is extruded into a sheet while being melt-kneaded and then cooled.

The pelletized or granular polypropylene used in the present invention has a melt flow rate of 0.2 g / 10 min to 5 g / 10 min measured under the conditions of 230 ° C. and a load of 2160 g. Blends can be used for any purpose. It is necessary that the polypropylene component used in the present invention contains at least 20% by weight of granular polypropylene. Here, the term “granular” means particles having an average particle size of 100 to 1200 μm in a content of 98% by weight or more and a bulk specific gravity of 0.5 or more. When granular polypropylene is used in combination with pellet polypropylene as the polypropylene component, the temperature of 230
It is necessary that the melt flow rate measured under the conditions of 2 ° C. and a load of 2160 g is equal to or higher than the melt flow rate of the pellet-like polypropylene measured under the same conditions. If the melt flow rate of the granular polypropylene is less than the melt flow rate of the pellet polypropylene or the blending amount of the granular polypropylene is less than 20% by weight, the mica is melt-kneaded in an extruder and the The dispersibility and surface condition are poor, and the composition unevenness of mica increases. Desirably, the range is 30 to 90% by weight. In the present invention, polypropylene and polyethylene are essential components as resin components, and when a pellet-like polypropylene is used as a part of the polypropylene, the polyethylene used in the present invention is a melt flow measured at a temperature of 230 ° C. and a load of 2160 g. It is necessary that the rate be equal to or higher than the melt flow rate of the pellet-like polypropylene measured under the same conditions. It is necessary that the blending amount of polyethylene is 3% by weight or more and 20% by weight or less. If the melt flow rate of the polyethylene is lower than the melt flow rate of the pellet-like polypropylene, it is melt-kneaded by an extruder, the dispersibility and surface state of the mica in the formed sheet are poor, and the composition unevenness of the mica increases. If the amount of polyethylene is less than 3% by weight, the dispersibility of the mica in the formed sheet is poor, and the composition unevenness of the mica increases. If it exceeds 20% by weight, the rigidity of the formed sheet is not sufficient, and the object of the present invention cannot be achieved. Desirably, the range is 5 to 20% by weight.

The mica powder used in the present invention can be appropriately selected from phlogopite (phlogopite), muscovite (muscovite), synthetic mica, etc., and these have a weight average flake diameter of 15 μm or more and 500 μm or less and a bulk specific gravity of 0.15. It is necessary to be above. If the weight average flake diameter is less than 15 μm, the rigidity of the formed sheet is not sufficient, and the dispersibility of mica deteriorates. On the other hand, if the weight average flake diameter exceeds 500 μm, the surface of the obtained sheet will be roughened, leading to difficulty in production. Further, in the case of mica having a bulk specific gravity of less than 0.15, biting into the extruder is poor, and not only the amount of the mica compounded fluctuates greatly, but also it is difficult to form a sheet by reducing the production amount.
Desirably, mica powder having a bulk specific gravity of 0.2 or more is desirable. These mica powders need to be blended in an amount of 10% by weight or more and 60% by weight or less in all the components. If the mica powder is less than 10% by weight, the effect of improving the rigidity of the obtained sheet is not sufficient, and if it exceeds 60% by weight, melt kneading with an extruder is difficult, and the sheet cannot be formed. Desirably 15% to 50% by weight
Is preferable.

The plastic sheet obtained in the present invention comprises, as essential components, polypropylene, polyethylene and mica powder in which at least 20% by weight of the above-mentioned granular polypropylene or the component is a granular polypropylene, and at least 20% by weight of the granular polypropylene or the component is a granular polypropylene. Polypropylene is 20% to 87% by weight, and polyethylene is 3% to 20% by weight.
Or less, and a compounding ratio of mica powder of 10% by weight or more and 60% by weight or less, but an antioxidant, a coupling agent, a release agent, a colorant, Addition of a flame retardant or the like can be no problem.

The plastic sheet used in the present invention is 0.1 to 5 mm thick
The sheet-like material in the range of, the apparatus for producing the sheet is a melt-kneading general-purpose single-screw extruder, a twin-screw extruder and the like, as a kneading screw full-flight screw, dalmage screw, Double flight screw and the like. Also, as a method of supplying the material to the extruder, a coil feeder, a twin-screw feeder, an electromagnetic feeder, etc., respectively, or a quantitative supply method in which the composition is mixed in a tumbler or the like in a fixed amount, a composition is mixed in a tumbler in a total amount. There is a natural feed type feeding into an extruder hopper. General-purpose T-
This is performed using a die and a sheet take-off machine.

However, the invention is not limited to said device,
Any device can be used as long as it can produce a plastic sheet having a thickness of 0.1 to 5 mm containing mica powder by one melt-kneading process.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

Example 1 15% by weight of phlogopite (trade name Szolite Mica) having an average particle size of 35 μm, a bulk specific gravity of 0.23, and a polypropylene pellet having a melt flow rate of 0.8 g / 10 min (hereinafter, referred to as “polysilica”)
15) Granular polypropylene (hereinafter abbreviated as PP) having a melt flow rate of 67% by weight and 1.5 g / 10 min
3% by weight of high-density polyethylene pellets (hereinafter abbreviated as PE) having a melt flow rate of 1.5 g / 10min and 1.5% by weight
Is supplied in a fixed amount using a feeder, melt-kneaded using a 65 mmφ extruder incorporating a full flight screw, extruded into a sheet shape using a T-die having a width of 1150 mm, and then cooled to obtain a sheet having a thickness of 2 mm. Was molded. The obtained sheet was measured for the following four items. As a result, the surface state, the dispersibility of the mica, the variation of the mica mixing ratio and the specific elastic modulus were all good, and the results are shown in Table 1.

Surface condition: Surface roughness observed with the naked eye.

Dispersibility of mica: A small piece was cut out from each of 10 places in the extrusion direction and the width direction and made into a thin plate having a thickness of about 0.2 mm using a flat plate heat press machine.

Variation in mica mixing ratio: Cut out small pieces from each of 20 places in the extrusion direction and width direction, measure the mixing ratio of mica by the burning loss method, and measure the variation from the average value.

Specific modulus: The flexural modulus is measured from the sheet extrusion direction in accordance with ASTM D790, and divided by the sheet specific gravity to calculate the specific modulus.

Example 2 Phlogopite having the same particle size and bulk specific gravity as in Example 1 was prepared.
30% by weight, 40% by weight of PP having the same melt flow rate as in Example 1, 25% by weight of granular PP, and 5% by weight of PE. 2m
m sheets were formed. The obtained sheet was subjected to the same performance evaluation as in Example 1. As a result, the surface state, the dispersibility of the mica, the variation in the mica mixing ratio, and the 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 prepared.
Example 1 except that 50% by weight, 45% by weight of granules PP having the same melt flow rate as in Example 1 and 5% by weight of PE were used.
A sheet having a thickness of 2 mm was formed by the same method and using the same apparatus. The obtained sheet was subjected to the same performance evaluation as in Example 1. As a result, the surface state, the dispersibility of the mica, the variation in the mica mixing ratio, and the specific elastic modulus were all good, and the results are summarized in Table 1.

Example 4 A PE having the same melt flow rate as
% By weight, except that 30% by weight of PP is used.
A sheet having a thickness of 2 mm was formed by the same method using the same apparatus. The obtained sheet was evaluated for performance in the same manner as in Example 1. As a result, the surface state, the dispersibility of mica, the variation in the mixing ratio of mica, and the specific elastic modulus were all good, and the results are summarized in Table 1.

Example 5 Muscovite having an average particle size of 18 μm and a bulk specific gravity of 0.20 (K.
A sheet having a thickness of 2 mm was formed using the same apparatus and the same composition as in Example 2 except that K. Kuraray (trade name, Clarite Mica) was used. The obtained sheet was evaluated for performance in the same manner as in Example 1. As a result, the surface state, the dispersibility of mica, the variation in the mixing ratio of mica, and the specific elastic modulus were all good, and the results are summarized in Table 1.

Example 6 Except for using phlogopite (trade name: Szolite Mica) having an average particle size of 280 μm and a bulk specific gravity of 0.35, a sheet having a thickness of 2 mm was formed using the same apparatus and the same method as in Example 2 using the same apparatus. Molded. As a result of performing the same performance evaluation as in Example 1 on the obtained sheet, the surface state, the dispersibility of mica,
Both the variation of the mica mixing ratio and the specific elastic modulus were good, and the results are summarized in Table 1.

Comparative Example 1 The same composition as in Example 1 except that 5% by weight of phlogopite having the same particle size and bulk specific gravity as in Example 1 and 77% by weight of PP having the same melt flow rate as in Example 1 were used. A sheet having a thickness of 2 mm was formed by the same method using the same apparatus. When the performance evaluation of the obtained sheet was performed in the same manner as in Example 1, the dispersion of the mica, the surface state and the variation in the mixing ratio of the mica were good, but the specific elastic modulus was low. Table 1 shows the results.

Comparative Example 2 Phlogopite having the same particle size and bulk specific gravity as in Example 3 was prepared.
70% by weight, the same composition as in Example 3 except that 25% by weight of granules PP having the same melt flow rate as in Example 3,
An attempt was made to form a sheet by the same method using the same apparatus, but kneading was difficult and the sheet could not be formed. Table 1 shows the results.

Comparative Example 3 PP having the same melt flow rate as
A sheet having a thickness of 2 mm was formed using the same apparatus and the same method as in Example 2 except that the weight% and PE were not used. When the performance evaluation of the obtained sheet was performed in the same manner as in Example 1, the specific elastic modulus was equivalent to that of Example 2.
Since PE was not added, the surface condition and the dispersibility of mica were poor, and the variation in the mica mixing ratio was as bad as about twice that of Example 2. Table 1 shows the results.

Comparative Example 4 PP having the same melt flow rate as in Example 2 was added to 20
% By weight, the same composition as in Example 2 except that 25% by weight of PE was used.
A sheet having a thickness of 2 mm was formed by the same method using the same apparatus. When the performance evaluation of the obtained sheet was performed in the same manner as in Example 1, the dispersion of the surface state and the mica mixing ratio was good, but the dispersibility of the mica was poor, and the specific elastic modulus was low. Table 1 shows the results.

Comparative Example 5 A sheet having a thickness of 2 mm was formed using the same apparatus and the same method as in Example 2, except that 5 wt% of PE having a melt flow rate of 0.6 g / 10 min was used. When the performance evaluation of the obtained sheet was performed in the same manner as in Example 1, the specific elastic modulus was good, but the dispersibility of mica was poor, and the surface state was poor.
The variation of the mica mixing ratio was bad. Table 1 shows the results.

Comparative Example 6 A sheet having a thickness of 2 mm was formed using the same apparatus and the same method as in Example 2 except that 25% by weight of granules PP having a melt flow rate of 0.5 g / 10 min was used. When the same evaluation as that of Example 1 was performed on the obtained sheet, the specific elastic modulus was good, but the dispersibility of mica was poor, and the surface state was poor.
The variation of the mica mixing ratio was bad. Table 1 shows the results.

Comparative Example 7 PP having the same melt flow rate as in Example 2 was 65
A sheet having a thickness of 2 mm was formed using the same apparatus and the same method as in Example 2 except that the weight% and the granular PP were not used. When the obtained sheet was evaluated in the same manner as in Example 1, the specific elastic modulus was good, but the mixing ratio of mica was very poor because granules PP were not used, and the dispersibility and surface state of mica Was also inferior. Table 1 shows the results.

Comparative Example 8 A sheet having a thickness of 2 mm was formed using the same composition and the same method as in Example 5 except that a muscovite (prototype) having an average particle diameter of 10 μm and a bulk specific gravity of 0.20 was used. When the obtained sheet was evaluated in the same manner as in Example 1, the dispersion of the surface state and the mixing ratio of mica was good, but the dispersibility of the mica was poor due to the small average particle size of the mica, and the specific elastic modulus was low. Was inferior. Table 1 shows the results.

Comparative Example 9 A sheet having a thickness of 2 mm was prepared using the same apparatus and the same method as in Example 6, except that phlogopite (trade name: Szolite Mica) having an average particle diameter of 650 μm and a bulk specific gravity of 0.35 was used. Molded. The same evaluation as in Example 1 was performed on the obtained sheet. As a result, the dispersibility of mica, the variation of the mixing ratio of mica, and the specific elastic modulus were good, but the surface state was very large because the average particle size of mica was large. Evil. Table 1 shows the results.

Comparative Example 10 The same composition as in Example 2 was quantitatively supplied using a feeder, and a full-flight screw-incorporated 65 mm
A pellet containing 30% by weight of mica was produced by melt-kneading using a φ extruder. After thoroughly tumbling the obtained pellet, 65 mm incorporating a full flight screw
The mixture was remelted and kneaded with a φ extruder, extruded into a sheet shape using a T-die having a width of 1150 mm, and a sheet having a thickness of 2 mm was formed. When the same evaluation as that of Example 1 was performed on the obtained sheet, the dispersion of the mica, the surface state, and the variation in the mixing ratio of the mica were good, but the specific elastic modulus was inferior to that of the example, and Melting and kneading are performed twice, which is disadvantageous in cost. Table 1 shows the results.

[Effect of the Invention] According to the present invention, an inexpensive mica powder-filled plastic sheet can be provided by using a one-stage sheeting process without impairing the excellent properties of the mica powder-filled composition.

Claims (4)

(57) [Claims] An essential component is a granular polypropylene, polyethylene and mica powder, wherein the compounding ratio of the granular polypropylene is 20% by weight or more and 87% by weight or less, and the compounding ratio of polyethylene is 3% by weight or more and 20% by weight or less. And, furthermore,
The mica powder has a weight average flake diameter of 15 μm or more and 500 μm or less, a bulk specific gravity of 0.15 or more, and a compounding ratio of 10% to 60% by weight.
A plastic sheet comprising the following composition. 2. A polypropylene comprising a polypropylene having a melt flow rate of 0.2 to 5 g / 10 min and a pellet polypropylene, wherein at least 20% by weight of the component is a granular polypropylene, polyethylene and mica powder. 20% to 87% by weight of polyethylene and 3% by weight or more of polyethylene
20 wt% or less, and the melt flow rate of granular polypropylene and polyethylene is 230 ° C, when measured under the condition of a load of 2160 g, is equal to or higher than the melt flow rate of pelletized polypropylene measured under the same conditions, , Mica powder is weight average flake diameter 15μm or more and 500μm
Hereinafter, a plastic sheet comprising a compound having a bulk specific gravity of 0.15 or more and a compounding ratio of 10% by weight or more and 60% by weight or less. 3. Granular polypropylene, polyethylene and mica powder are essential components, and the blending ratio of the granular polypropylene is 20% to 87% by weight, and the blending ratio of polyethylene is 3% to 20% by weight. And, furthermore,
The mica powder has a weight average flake diameter of 15 μm or more and 500 μm or less, a bulk specific gravity of 0.15 or more, and a compounding ratio of 10% to 60% by weight.
A method for producing a plastic sheet, comprising extruding the following compound into a sheet while melting and kneading the mixture, followed by cooling. 4. Polypropylene, polyethylene and mica powder having a melt flow rate of 0.2 to 5 g / 10 min, comprising granular polypropylene and pelletized polypropylene, wherein at least 20% by weight of the component is granular polypropylene. 20% to 87% by weight of polyethylene and 3% by weight or more of polyethylene
20 wt% or less, and the melt flow rate of granular polypropylene and polyethylene is 230 ° C, when measured under the condition of a load of 2160 g, is equal to or higher than the melt flow rate of pelletized polypropylene measured under the same conditions, , Mica powder is weight average flake diameter 15μm or more and 500μm
A method for producing a plastic sheet, comprising extruding a compound having a bulk specific gravity of 0.15 or more and a compounding ratio of 10% by weight or more and 60% by weight or less into a sheet while melting and kneading the mixture, followed by cooling.