JPS61157561A - Mica composition - Google Patents

Abstract

PURPOSE:To provide a granular or pellet mica composition containing powdery mica and a specific amount of an organic binder as essential components, having specific bulk density and particle diameter, and excellent handleability and performance, and suitable as a reinforcing filler for resins. CONSTITUTION:The objective composition having a bulk density of >=0.6g/cc and particle diameter of 0.3-10mm can be produced by using (A) powdery mica (e.g. having a weight-average flake diameter of 10-300mum and weight- average aspect ratio of >=10) and (B) 0.5-10wt% organic binder (e.g. epoxy compound) based on the whole composition, as essential components.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to the field of composite materials, in particular to a granular or belent material containing mica as a main component, which is suitable for use as a filler for reinforcing resins, and has good handling and performance. composition.

[Conventional technology]

Mica powder has already been widely used as a filler for resins due to its excellent mechanical properties, electrical properties, heat resistance, and other features.

[Problems to be solved by the present invention]

However, mica powder has a lower bulk specific gravity than general-purpose resin fillers such as talc, calcium carbonate, barium sulfate, and wollastonite, so there are problems with scattering during handling and associated environmental pollution, and problems with extruder processing. When kneading with resin using the same method, the problem of segregation of resin pellets/mica powder in the extruder hopper has been pointed out.

Mica can be made into mica powder with a high bulk specific gravity by selecting the grinding method, but when such mica powder is kneaded with resin, it has a poor effect on improving the mechanical properties of the resin, and it is difficult to use for resin. It cannot be said that it is suitable as a filler.

In addition, mica powder, like general-purpose fillers such as talc, calcium carbonate, barium sulfate, and wollastonite, has the problem of accelerating resin deterioration when filled into resin, especially when heated. It had Although it is possible to improve the deterioration of resin in the presence of mica to a level where there is no practical problem by using a stabilizer for the resin, it is necessary to use a large amount of stabilizer, which reduces the cost. Increase and stabilizer bleed were pointed out as problems.

The present invention was carried out with the aim of improving the handling properties of mica powder as a filler for reinforcing resins while retaining their original characteristics, and at the same time reducing the deterioration effect on resins.

[Means for solving problems]

The inventors of the present invention have conducted intensive studies on the development of mica that is easy to handle and has little deterioration effect on resin. The present inventors have discovered that a mica composition having a specific specific gravity and a specific shape obtained by treating the above problems can simultaneously improve the above-mentioned problems, and have completed the present invention.

That is, the present invention uses mica powder, preferably mica powder having a weight average flake diameter of 10 to 300 μm and a weight average aspect ratio of 10 or more, and 0.5% by weight or more and 10% by weight or less of the total composition weight. The organic binder is an essential component, the bulk specific gravity is 0.6 f/cc or more, and the particle size is 0.6 f/cc or more.
It is a granular or pelleted mica composition of 3 to 10 wn.

Note that the physical property values described above are values determined by the measurement method defined below.

(a) Weight average flake diameter of mica powder (1) Mica powder was passed through standard sieves with various openings for wet classification, the results were plotted on a Rosin-Ramm1ar plot diagram, and the mica powder used for measurement was The opening lso of the sieve through which 50% by weight of the powder passes is determined, and the value is calculated from this value using equation (1).

1 = f'bo (1) (b) Using the weight average aspect ratio (α) of mica powder, the weight average flake thickness d, and the weight average flake diameter l obtained from equation (1), (2 ) is the value obtained from the formula.

α= l/d (2) Φ Note that the weight average flake thickness d in equation (2) is determined by the water surface single particle removal method [C, E Capes and R, CCol
eman 11th, Eng, Chem, Fou
ndam, 12.124, (1973)], using the occupied area S of the flakes on the water surface, (
3) Calculated using the formula.

d=1:il (3) Here, W is the weight of mica used for measurement, S is the area occupied by the mica single particle film on the water surface, ρ is the specific gravity of mica, (1
-ε) is the occupancy rate when mica is in a close-packed state on the water surface, and the value of ρ is 2.86 f/CC.
As the value of (1-ε), 0.9 is used in the calculation.

(e) Bulk specific gravity of mica powder According to JIS K5101, mica powder falling from a funnel is received in a receiver with a diameter of 50 mm and a capacity of 100 cc using a powder tester PT-D made by Micron ■, and its weight is calculated. This is the calculated value.

(d) The bulk specific gravity of the mica composition is a value calculated based on the volume and weight of a pellet or granular mica composition placed in a measuring cylinder with a volume of 100 cc.

The mica used in the present invention can be widely selected from muscovite, phlogovite, biotite, synthetic 70a70 govite, etc., and is not particularly limited, but considering the performance and cost as a filler for resin, muscovite, (
White mica) and phlogovite (gold mica) are most preferably used.

It is particularly preferable that the mica powder used in the present invention has values in specific ranges in weight average flake diameter, weight average aspect ratio, and bulk specific gravity. That is, the weight average aspect ratio of the mica powder used in the present invention is preferably 10 or more, more preferably 20.
It is particularly desirable that it is above. 7 types of mica used
Granulation or pelletization (hereinafter simply referred to as granulation) is easier when the aspect ratio is lower, but when the aspect ratio is 1
Granular or pelleted mica compositions (hereinafter sometimes simply referred to as granulated compositions) obtained using mica powder of 0 or more have a particularly effective effect of improving the mechanical properties of the resin when filled into a resin. get well.

The weight average flake diameter of mica used in the present invention is preferably 10 to 300 μm, preferably 10 to 300 μm.
~20011WLs More preferably 30~100μ7
It has been found that the effect of improving mechanical properties is particularly good when the temperature is 71%. Furthermore, a granulated composition using mica powder with a flake diameter of 10 μm or more has particularly good dispersion when the composition is kneaded with a resin, but on the other hand, the flake diameter becomes large, especially 300 μm or more. mica powder requires an extremely large amount of binder when granulated.

The bulk specific gravity of the mica powder when producing the composition of the present invention is preferably 0.4 f/cc or less, preferably 0.15 to 0.35 f/cc, and more preferably 0.15 f/cc.
~0.30 The obtained composition tends to have insufficient effect on improving the mechanical properties of the resin. There is no particular limit on the lower limit of the bulk specific gravity, but if the bulk specific gravity is 0 using a general crushing method.
．． It is extremely difficult to produce mica powder below 15 f/cc.

In the composition of the present invention, a silane coupling agent,
There are no restrictions on the use of mica powder treated with a surface treatment agent such as a titanate coupling agent.

The organic binder component 9 used in the present invention needs to have fluidity at the temperature at which the granulation operation is performed, preferably at room temperature, and the viscosity at that time is desirably 1 poise or less. In other words, a resin that is liquid at room temperature can be used as it is as a binder component in the present invention, but a resin that is solid can be used after being heated to an appropriate temperature, or as a solution using an appropriate solvent. or as an emulsion. Further, for the binder to be used as a solution or emulsion, it is necessary that the binder has substantial fluidity at the temperature at which the granulated product and resin are kneaded with the solvent or medium removed.

The type of organic binder is not particularly limited as long as it satisfies the above requirements, but generally includes epoxy resin, urethane resin, polyvinyl acetate, ethylene-vinyl acetate copolymer,
Thermoplastic polyester, polystyrene, and modified products or blends containing these as main components. Among these, epoxy resin is extremely effective in preventing thermal deterioration of the resin when the resin is filled with a granulated composition. It is a particularly desirable binder component because it contributes to

The content of the binder component in the granulated composition is 0.
The content is preferably 5 to 10% by weight, preferably 0.5 to 5% by weight, and more preferably 0.5 to 3% by weight. Although it is desirable for the binder component to be large in terms of ease of granulation operation and compressive strength of the granulated composition, the mechanical properties of the resin blended with the granulated composition From this point of view, the upper limit of the content of the binder component in the granulated composition is 10% by weight or less, since it decreases as the binder component increases.
In order to obtain a granulated composition with such a small amount of binder, preferably 5% by weight or less, more preferably 3% by weight or less, mica powder having a specific shape as described above is used. This is necessary.

On the other hand, the lower content of the binder component is determined as the lowest content at which the mica powder can be substantially granulated and the granulated composition maintains an appropriate compressive strength. When using an epoxy resin as a binder component and considering heat deterioration resistance, it is preferably used in an amount of 0.5% by weight or more, particularly 1% by weight or more.

There are no particular restrictions on the method for producing the granulated composition of the present invention, but a general method is to thoroughly mix the mica powder and the binder component in a temperature range where the binder component has fluidity, and then mix the mica powder and the binder component under appropriate pressure. It is produced by agglomerating mica powder in a process such as the so-called transfer flow method, extrusion granulation method, compression granulation method, fluidized bed granulation method, mixed type granulation method, etc. Of these granulation methods, the internal extrusion granulation method or the compression granulation method is a particularly preferred process in that a granulated X-formed composition with a high bulk specific gravity can be easily obtained by adding a small amount of binder component.

The bulk specific gravity of the granulated composition in the present invention is 0.6 f/c
c or more is required. Bulk specific gravity is 0.6 f
/cc or less granulated composition can reduce scattering during handling, but resin pellets /cc or less in the extruder hopper can be reduced.
The problem of mica segregation cannot be resolved.

The size of the granulated composition in the present invention is 0.3 to 10W
+, preferably 0.5 to 5 m. Particle size is 0.3m
For granulated compositions of less than m, scattering during handling becomes a problem.
On the other hand, a granulated composition having a particle size of 10 square meters or more cannot be used because it causes problems in handling when kneading with a resin.

The granulated composition of the present invention contains mica powder and a binder as essential components, but other fillers such as talc, calcium carbonate, and wolast may be added within a range that does not impair the performance of mica. Night, barium sulfate, clay, silica, etc. may be used in combination, and deterioration inhibitors, stabilizers, lubricants, antistatic agents, flame retardants, foaming agents, crosslinking agents, pigments, etc. may also be added. be.

The granulated composition of the present invention is used by being filled into thermoplastic resins and thermosetting resins due to its excellent handling properties and the property that it does not have an adverse effect on thermal deterioration of the resin. There are no particular restrictions on the method of filling the resin with the granulated composition, and methods using a single-screw or twin-screw extruder, kneader, calender roll, etc. can provide good handling of the granulated composition. , easily filled. In particular, conventionally, when mica powder and resin are mixed using an extruder, there is segregation of mica powder/resin pellets in the hopper, fluctuations in the mica content of the manufacturing compound based on this, and a decrease in mica powder. There have been problems such as poor feeding from the hopper to the extruder due to the bulk specific gravity, but all of these problems can be solved by using the granulated composition of the present invention.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but these Examples are not intended to limit the present invention in any way. In addition, the flake diameter and aspect ratio in the examples relate to the weight average.

Examples 1 to 9 Gold mica-A (flake diameter 40μ, aspect ratio 30
, bulk specific gravity 0.25 f/cc), gold mica-B (
Flake diameter 280μ, aspect ratio 701, bulk specific gravity 0.
351/cc), gold mica-c (flake diameter 15μ
, aspect ratio 20. Bulk specific gravity 0.21 f/cc)
and epoxy resin emulsion (solid content zowt
The experiment was conducted using a bisphenol A type epoxy resin with an epoxy equivalent of 1901 and a viscosity of 120 poise. Epoxy resin emulsions were added to gold mica-A, B, and C so that the blending ratio of epoxy resin solids to mica was as shown in Table 1, and the mixture was thoroughly mixed using a double-arm kneader. The mixture was passed through a roll extrusion granulator (
The mixture was extruded and cut through a dis-die under pressure by a roll to form a cylinder with a diameter of about 3mm and a length of about 56mm, and then]ooo
The pelletized mica composition was mixed by drying at c for 3 hours. In both cases, granulation properties were good. All of the pelletized mica compositions obtained had a bulk specific gravity of 0.6 f/cc or more, and no dust was observed during handling.

The pelleted mica, polypropylene (melt index: 5 f/10 min), and r-aminopropyltriethoxysilane were mixed in such a way that the mica weight fraction in the mixture was 40% by weight, and the r-aminopropyltriethoxysilane was 40% by weight of the mica weight. The mixture was mixed to 0.5% by weight, and the mixture was fed to a single screw extruder (40 φ, L/D = 28) at a cylinder temperature of 230°C and a screw rotation speed of 4 ORP.
Mica-filled polypropylene was obtained by kneading under the conditions of M. The mica pellets were well incorporated into the extruder hopper, and no segregation was observed. Pelleted mica/
When kneading 20 kg of polypropylene, the mica content in the resulting pellets varied within a range of 40 ± 1% by weight, which was extremely stable, and the discharge rate was approximately 11 kg/b.
It was as high as r. The obtained mica/polypropylene pellets were press-molded at 230° C. to form a sheet with a thickness of 0.2 mm, and visual judgment showed that the dispersion of mica into polypropylene was good in all cases.

The mica-filled polypropylene was supplied to a screw in-line type injection molding machine with a capacity of 4 mm, and injection molding was performed at 230°C to obtain a dumbbell-shaped test piece specified in JIS D-638. The tensile strength of the test piece was good as shown in Table 1. In addition, when the test piece was thermally degraded in an open gear kept at 140°C and the time required for the tensile strength to decrease to 50% was measured, the results are shown in Table 1. All compositions showed good values. Ta.

Comparative Example 1 Using gold mica-A without granulation treatment, Example 1
It was kneaded with polypropylene in the same manner and under the same conditions as in cases 9 to 9. When mixing gold mica and polypropylene pellets, significant scattering of mica was observed.

In addition, significant segregation of the mixture in the extruder hopper was observed, and in the mica/polypropylene kneading process in 2019, the mica content in the resulting pellets varied by 39 parts.
%, extremely significant fluctuations were observed. Discharge amount is also 8.5
kq/hr, which was an extremely low value compared to Examples 1 to 9. The tensile strength of the test pieces obtained by injection molding the pellets was almost the same as in Examples 1 to 9, but the thermal deterioration resistance was extremely poor. Details of the results are shown in Table 1.

Comparative Example 2 The epoxy resin emulsion used in Examples 1 to 9 was heated to evaporate water to obtain an epoxy resin.

Using the epoxy resin, a mixture of polypropylene (57 parts)/gold mica A (40 parts)/epoxy resin (3 parts)/r-aminopropyltriethoxysilane (0.2 parts) was obtained. The mixture was kneaded using an extruder in the same manner and under the same conditions as in Examples 1 to 9, but the behavior at that time was the same as in Comparative Example 1. Problems such as segregation of mica, fluctuation of mica content in pellets, and insufficient discharge amount were observed. As shown in Table 1, the performance of the test piece injection-molded from the kneaded product was almost satisfactory in tensile strength, but poor in heat deterioration resistance.

Comparative example 3.4 Gold mica-D (flake diameter 440 μm, aspect ratio 7
The experiment was conducted using the same epoxy resin emulsion as in Examples 1 to 9 with a bulk specific gravity o of 35 f/cc). Even if the gold mica D/epoxy resin emulsion mixture contains 10% by weight of the epoxy resin component, Examples 1 to 9
Granulation was impossible with the granulator used in (Comparative Example 3). Granulation became possible by setting the epoxy resin component to 15% by weight, but the tensile strength of the composition consisting of the granules and polypropylene was extremely low as shown in Table 1.

Examples 10 and 11 Gold mica E (flake diameter 5μ, aspect ratio 20, bulk specific gravity o, 20 f/cc) or gold mica-F (flake diameter 20μ, aspect ratio 7, bulk specific gravity 0.2817/cc)
cc) and the same epoxy resin emulsion as in Examples 1 to 9, the same experiments as in Examples 1 to 9 were conducted. Granulation properties were good in all cases. A kneaded product consisting of the granulated pellets and polypropylene was produced using the same extrusion method and under the same conditions as in Examples 1 to 9, but the composition of Example 10 was prepared by adding mica to poly-10-pyrene. The dispersion was somewhat poor and, reflecting this, the tensile strength of the test piece obtained by injection molding the composition was also somewhat low.

Example Composition 1 had no problem with dispersion of mica into polypropylene, but its tensile strength was somewhat unsatisfactory.

Comparative Example 5 Using gold mica-C, the blending ratio of the epoxy resin component was 0.3
Exactly the same experiment as in Examples 1 to 9 was conducted except for the weight %, but no granules were obtained.

Example 12 The same experiment as in Examples 1 to 9 was conducted except that gold mica-C was used and the blending ratio of the epoxy resin component was 1% by weight. Although some difficulty was observed in granulation, granulation was possible, and a pellet-like composition with a rather low bulk specific gravity (0.65 f/cc) was obtained. The performance of the pelletized composition was evaluated by kneading it into polypropylene, and as shown in Table 1, the handleability and physical properties were good.

Comparative Example 6 The same experiment as in Examples 1 to 9 was conducted except that gold mica B was used and the blending ratio of the epoxy resin component was 1% by weight. Although granulation was possible, the granules had poor compaction, contained powdered mica, and had a low bulk specific gravity (
0.52 f/cc). The pelletized composition was kneaded with polypropylene using the same equipment and conditions as in Examples 1 to 9, but segregation was observed in the extruder hopper and the mica content in the resulting pellets varied greatly ( 39±5%).

The discharge amount was also low at 9.5 kq/br.

Examples 13 to 15 Examples 1 to 15 were carried out using gold mica-A and ethylene-vinyl acetate copolymer emulsion (Example 3), polyvinyl acetate emulsion (Example 14), and SBR emulsion (Example 15). Exactly the same experiment as in case 9 was conducted. All emulsions were used after adjusting the solid content concentration to 20 weight.

In all cases, the granulation properties were good, and the granules were also easy to handle. The performance of the polypropylene blended with the granules is as shown in Table 1.
Although inferior to compositions No. 9 to 9, the performance was quite satisfactory.

Examples 16-18 White mica-A (flake diameter 40μ, aspect ratio 35,
Experiments were conducted using the epoxy resin emulsion used in Examples 1 to 9.

In Example I6, the same roll type extrusion granulator (pellet mill) as in Examples 1 to 9 was used, but 5j! In Example 17, a high-speed rotation type mixing type granulator (Bingranulator) was used, and in Example 18, a ram-type extrusion granulator was used for granulation.

In Example 18, a pellet-like composition having the same shape as in Examples 1 to 9 was obtained, but in Example 17, a granular composition with an average particle size of 1.6 W+ was obtained. The handleability and performance of these compositions were both good, as shown in Table 1.

〔Effect of the invention〕

According to the present invention, a pellet-like or granular mica composition is provided, which retains the original characteristics of mica powder as a resin-reinforcing filler and has significantly improved handling properties. The mica composition has the advantage that when blended with a resin, the deterioration effect on the resin is reduced compared to conventional mica powder.

Claims (1)

[Claims] 1) mica powder and 0.5% by weight or more of the total composition weight;
Bulk specific gravity of 0.6 g/cc or more and particle size of 0.3 to 10 mm, containing 0% by weight or less of an organic binder as an essential component
A granular or pelleted mica composition. 2) The mica composition according to claim 1, which uses mica powder having a weight average flake diameter of 10 to 300 μm and a weight average aspect ratio of 10 or more. 3) The mica composition according to claim 1 or 2, which uses an epoxy compound as the organic binder component.