JPS58108241A - Mica-containing propylene polymer composition - Google Patents

Abstract

PURPOSE:To prepare a composition having remarkably improved dimensional accuracy, sink mark and warpage, and having excellent and balanced rigidity, heat resistance, impact resistance, and moldability, by compounding a specific mica to a specific propylene polymer. CONSTITUTION:A composition having a mold shrinkage of <=0.8% is prepared by compounding (A) 25-90wt% resin comprising a propylene polymer resin or a composition obtained by adding a synthetic rubber thereto, and containing 10- 50% component extractable with xylnen at 23 deg.C wherein the propylene content in the extractable component is >=30%, with (B) 75-10% mica having an average particle diameter of <=200mu determined by the light transmission using the liquid-phase sedimentation method. The component (A) is preferably a crystalline propylene-ethylene block copolymer having an ethylene content of <=30% or a combination of the copolymer with an ethylene-propylene copolymer rubber, and the component (B) is preferably phlogopite.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a propylene polymer resin composition with extremely good dimensional accuracy achieved by blending specific components.

Polypropylene is used in large quantities as a general-purpose resin with excellent stiffness, heat resistance, electrical properties, chemical stability, and high moldability.

However, since polypropylene is a crystalline resin, the dimensional accuracy of injection molded products is poor, and it has major drawbacks such as sink marks and warpage. For this reason, polypropylene was rarely used in applications that required a high degree of dimensional accuracy, such as precision parts, office equipment, and home appliance parts.

It is known that blending inorganic fillers is an effective method for improving the dimensional accuracy of polypropylene. It is known that plate-like and fibrous fillers are especially effective. However, when fibrous fillers, such as glass fibers, are added, Anisotropy in the molding shrinkage rate occurs with respect to both the horizontal and horizontal directions.

Specifically, although the molding shrinkage rate in the vertical direction can be improved to a smaller level of 0.4 to 0.8%, compared to 1.6 to 2.0% for polyglopylene harp bodies, The contraction rate in the vertical direction is 0.5 or more than that in the vertical direction.

As a result, extremely large warpage occurs in the molded product, and the method cannot be applied to precision parts or products requiring a high quality appearance.

Among plate-shaped fillers, talc is known to be superior in terms of rigidity, impact resistance, etc. of the substitute compound mixed with polypropylene.

``Polypropylene compositions containing mica have an excellent balance of rigidity, impact resistance, heat resistance, moldability, etc., so this book can respond to the recent market demands for these balances. Conventional polypropylene compositions that simply contain mica do not have a sufficient effect of improving dimension precision and also cause sink marks, so they are limited as practical molding materials.

The inventors of the present invention have conducted extensive studies in light of these circumstances, and have developed a propylene polymer composition containing 10 to 75% by weight of mica and having a molding shrinkage rate of 0.8 or less. Therefore, dimensional accuracy is excellent, and sink marks and warpage are eliminated.
It is a propylene polymer material that has an excellent balance of rigidity, heat resistance, impact resistance, and moldability, and can be applied to a wide range of applications such as precision parts, office equipment, and various *W parts. The object of the present invention is to dramatically improve the strength and warpage of dimensional electroluminescence and molded products, and to achieve an excellent balance of rigidity, heat resistance, impact resistance, and moldability. An object of the present invention is to provide a propylene polymer composition having the following properties.

That is, the present invention is a propyne polymer composition having a molding shrinkage rate of 0.8 or less, which is characterized by consisting of F (a) and (b) Fjt.

(a) A propylene polymer resin, in which case a synthetic rubber is blended into a composition, (1) Extractable content of 23°C
(2) The content of propylene in the extracted soluble matter is 30 weight or more. ...
......25~90 weights @ My cuff 5 weights 10 weight g # The average particle diameter measured by the light transmission method using the liquid phase sedimentation method is 200p or less #Thus, the present invention group Fi! It is a suitable application material for products that require dimensional accuracy and a high degree of appearance.

Component (a) of the propylene composite composition used in the present invention is a crystalline homopolymer of propylene polymerized using a Ziegler or Natsuta type catalyst or a mixture of propylene and other α-olefins. Crystalline copolymer with *@
, or optionally a composition in which synthetic rubber is blended with these polymer resins, (1) the extractables in xylene at 23° C. is 10 to 50% by weight; The propylene content is 30% by weight or more.

By the way, a-olefins other than propylene have 2 carbon atoms.
~12 books, including ethylene.

The majority of the constituent units of the crystalline propylene-based polymer resin are M41
E-propylene, specifically, for example, crystalline propylene, ethylene block or random copolymer, crystalline propylene/butene block random copolymer, and crystalline propylene.

Hexene block or random copolymer, crystalline propylene/heptene block or random copolymer, crystalline propylene, cypress, butene copolymer, etc.
Among these, crystalline propylene and ethylene block copolymers with an ethylene content of less than 0 volts are preferred.

Like this, crystalline propylene polymer! #1 Use 41 drops of IVr, which is available on the market.

In addition, the synthetic rubber used in the present invention is el, for example, ethylene-propylene copolymer rubber (EPM, EPD).
MI, styrene-butadiene copolymer rubber (8BR, S
BS block copolymer) or its hydrogenated product, isoprene rubber, isoprene, isobutylene rubber, and the like.

Among them, ethylene-propylene copolymer rubber is preferred.

As a substitute for the combination, a composition consisting of crystalline propylene, an ethylene block copolymer and an ethylene, 7° propylene copolymer rubber is particularly preferable in terms of value and quality balance.1. stomach.

The xylene soluble content at 23°C is measured by placing 3 tons of the sample in 1000ml of boiling xylene, allowing it to cool to 23°C, heating it in a furnace, separating the soluble content, and measuring its weight. The propylene content in the extracted soluble matter is measured by separating the xylene in the extracted soluble matter and then detecting the precipitate with an infrared spectrophotometer.

Next, the mica that can be used in the present invention as component (b) has an average particle size of 200 μm or less.

Preferred mica has an average particle size of 100 μm or less and a specific surface area of 3.000 aI/f or more.

The particle size distribution of mica here is measured by a light transmission method using a liquid phase sedimentation method. As a measuring device, there is a CP type manufactured by Takafusa Seisakusho. The average particle size is the particle size at the 50% point on the particle size distribution integral white line. Further, the specific surface area is measured using a constant pressure ventilation type specific surface area measuring device based on the so-called air permeation method, which is a conventional method, such as the powder specific surface area measuring device 88-10 manufactured by Takafusa Seisakusho.
Measure with 0 etc.

Such mica includes white mica series mica, white mica, red mica, soda mica, silk mica,
Vanadine mica, illite, etc., and mica of the Aki mica series,
In other words, black mica, gold mica, Chinwald mica, etc. are all mentioned.

Among them, for example, structural formula KA12 (AISi30to
)((')()s White mica or, for example, KMgs
(AISi30to) (0'02 or &Mga, 5F
et, zA1o, nCAlz, 5Sis, 5Ozo) (
OR>4F'.

Gold mica represented by is preferred.

The mica used in the present invention may be used without surface treatment, but it may also be surface treated with various surface treatment agents. Surface treatment agents include waxes such as low molecular weight polyethylene and low molecular weight polypropylene, saturated higher fatty acids such as stearic acid and )2-lumitic acid, saturated higher fatty acid metal salts such as magnesium stearate, unsaturated higher fatty acids such as oleic acid, Incurable higher fatty acid metal salts such as magnesium oleate, gutanate coupling agents such as isopropyl triisosteric titanate, silane coupling agents such as r-aminopropyltriethoxysilane, and polyoxyethylene alkyl ethers are Various surfactants and the like can be used.

These (a) and (b) components are such that (a) component is 25
~90% weight loss and component (b) is used at a ratio of 75% to 10 weight loss. - Compositions outside these ranges will have a poor balance of physical properties and cannot be put to practical use. Additional ingredients can also be added outside the company. Additional components include antioxidants such as phenolic, sulfur, and phosphorus; derivatives of higher fatty acids such as metal salts, amides, and esters; organic or inorganic pigments; ultraviolet absorbers;
Antistatic agent: Copper damage inhibitor: Neutralizing agent; Anti-bubble agent; Flame retardant; Thermoplastic resins and fillers other than those used in the present invention may be used. In particular, combinations of conductive fillers such as carbon black, calcium carbonate, or maleic anhydride-grafted propylene polymers are useful as functional compositions. The composition of the present invention is produced using a conventional mixer such as a single-screw extruder, a twin-screw extruder, a combinatorial mixer, a roll, and a Prabender plastograph. Normally, it is kneaded using an extruder or the like to form pellet-like Con-ζ land, which is then subjected to processing, but in special cases, it can be processed.

It is also possible to directly feed the lopyrene polymer resin and mica to various molding towers and knead them in a molding machine to form a molded product.

The composition of the present invention has extremely excellent dimensional accuracy, and also has good heat resistance and rigidity. In particular, as the above component (a), (1)
2' 3℃ xylene extraction soluble content is 15-50 wtlp1%
and (2) 25 to 80 weight percent of propylene content in this extracted soluble matter is 35% by weight or more, and (b) mica with an average particle size of 200 tones or less as a component. It has revolutionary properties as a crystalline propylene polymer composition, with a molding shrinkage rate of 0.6% or less and almost no sink marks or warpage in molded products. We have achieved good dimensional accuracy with the same rigidity as non-grade resins such as acrylonitrile, butadiene, styrene resin, and polystyrene.

As a result, precision parts, office equipment, double electrical parts, such as watch parts, copying machine housings, sewing machine housings, etc., which conventional crystalline propylene polymer compositions have not been able to penetrate,
It is characterized by being extremely suitable for use in video tape cassettes, audio tape cassettes, television front panels, radio cassette housings, etc., and has extremely great practical value. I will explain in detail.

In the example, the molding shrinkage rate is as follows: A rod-shaped sheet of 127 (length) x 12.7 (width) x 2 (thickness) is injection molded, and this is
After conditioning at 3°C for 24 hours, the length and width of C were measured at 23°C, the ratio to the mold dimension was determined, and the average value was taken.

Further, the bending elastic modulus was measured according to JIS K-7203, the heat distortion temperature was measured according to JIS K-7207 (4,6 to /- load), and the DuPont impact strength was measured according to JIS K-6400.

Example 1 Copolymerization of propylene and ethyne using a Ziegler-Natsuta catalyst resulted in a melt flow rate of 21% by weight of xylene extractables at 23°C with an ethylene content of 15% by weight. Crystalline propylene that is Of / 10 minutes
An ethylene block copolymer (4) was obtained. The propylene content in the soluble matter extracted with xylene at 23° C. in (2) was 50%.

70 parts by weight of this powder, average particle size 2o, specific surface area 1
6,000 cd/f of Canadian gold mica, 3.0 parts by weight, and 0.0 parts of 2,6-di-t-butyl-4-methylphenol.
1 part by weight and tetrakis [methylene (3,5-sheet t
--1 thyl-4-hydroxyhydrocinnamate)] Memetsu 00. The parts by weight were uniformly mixed in a super mixer, then kneaded in a 30-diameter twin-screw extruder to form pellets, and the pellets were molded into test pieces at 240°C in a screw in-line injection molding machine. The test pieces were evaluated.

For comparison, the propylene-ethylene block copolymer (■), a crystalline propylene homopolymer (■) having a melt flow rate of 10 f/10 minutes, and 70 parts by weight of this (■) and 30 parts by weight of the same mica as above were prepared in the same manner. and 79 parts by weight of crystalline propylene alone IJ valley body and 21
parts by weight of ethylene-propylene copolymer rubber (EPO manufactured by Mitsubishi Yuka Co., Ltd.) are mixed and kneaded, and the melt flow rate is 1.
Xylene extraction at 0f/10 minutes at 23°C Soluble content (contains propylene! 28% by weight) 21 weight 07.0 parts by weight of horseradish and 30 parts by weight of the same mica as above were mixed in the same way. The specimens were injection molded and evaluated.

These results are shown in Table 1.Example 2: 100 parts by weight of a crystalline propylene-ethylene bicarbonate copolymer obtained by copolymerizing propylene and ethylene using a Ziegler-Natsume catalyst. - Propylene copolymer rubber (EPoyP) was mixed and kneaded to obtain a propylene/ethylene copolymer composition containing 18% by weight of ethylene and 30% by weight of xylene extractables at 23°C. The propylene content in the xylene-extractable component of this composition at 23° C. was 45% by weight.

A copolymer composition having an average particle size of lOμ and a specific surface area of 2
After mixing and kneading 5,000 aJ/f of white mica in various ratios, test pieces were injection molded in the same manner as in Example 1.
Physical properties were measured.◎ As can be seen from the results summarized in Table 2, the dimensional accuracy and appearance of the molded products in all Examples were extremely good, and the rigidity, heat resistance, and impact resistance were extremely excellent.

Example 3 70 parts by weight of the same crystalline propylene-ethylene block copolymer (b) powder as in Example 1 and 30 parts by weight of mica were added with a specific surface area of 1.000 w? Similarly, 10 parts by weight of Ketjen black (highly conductive carbon fiber) of /f was added to 10,000 weight of the total amount of powder and mica, and mixed and kneaded together with a small amount of antioxidant in the same manner as in Example 1. When the test piece was injection molded and evaluated, the molding shrinkage rate was 0.6% or less and the conductivity was extremely good.

Patent applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent Attorney Hidetoshi Furukawa Agent: Patent Attorney Masahisa Nagatani

Claims (1)

[Scope of Claims] A propylene polymer composition having a molding shrinkage rate of 0.8% or less, characterized by consisting of components (a) and (b) in F. (a) Propylene polymer resin, optionally A composition in which synthetic rubber is blended with this is:
(2) The content of propylene in the extracted soluble matter is 30 times higher than 30 times.・
...... 25-90% by weight (h) Mica with an average particle size of 2001 or less as measured by the light transmission method of liquid phase sedimentation method...75-10% by weight