KR100472556B1 - High Gloss Polypropylene Resin Composition - Google Patents

Abstract

In the present invention, precipitated barium sulfate having an isotactic pentad fraction of boiling heptane insoluble portion of not less than 0.96% and a high crystalline polypropylene homopolymer having a melt index of 5 to 40 g / 10 min, having an average particle size of 1.0 μm or less. It relates to a high gloss polypropylene resin composition having excellent surface hardness and heat resistance, characterized by containing 1 to 10% by weight of talc having a ˜35% by weight and an average particle size of 4 μm or less.

Description

High Gloss Polypropylene Resin Composition

The present invention relates to a high gloss polypropylene resin composition having excellent surface hardness and heat resistance, and more particularly, the present invention is a polypropylene resin composition containing a high crystalline polypropylene resin and an inorganic filler, and has excellent moldability during injection molding. The present invention relates to a resin composition having excellent surface hardness, heat resistance, and glossiness of a molded product.

In general, polypropylene, which is a polyolefin resin, is a kind of thermoplastic resin and is widely used because of its excellent processing characteristics such as easy handling and regeneration. In addition, polypropylene resin improves its function by using inorganic fillers as its usage increases, while developing materials with excellent physical, chemical, and mechanical properties by supplementing shrinkage and thermal properties, thereby increasing the amount in the fields of home appliances and automobiles. It is used. In addition, the composition in which various inorganic fillers are blended with the polypropylene resin has improved stiffness, dimensional stability, glossiness, and the like, and in particular, mechanical properties, surface glossiness, heat resistance, etc. in which barium sulfate and talc are blended are improved. . As such a high gloss polypropylene resin composition, a composition in which an inorganic compound (for example, talc, barium sulfate, calcium bicarbonate) is blended into a polypropylene resin is disclosed in Japanese Patent Application Laid-Open No. Hei 6-43557 and Japanese Laid-Open Patent Publication No. 60-212452. It is disclosed in the call. However, the composition developed in this way is relatively inferior in stiffness of the crystalline polypropylene used, and contains a large amount of inorganic fillers to impart heat resistance. Therefore, gloss, heat resistance, surface scratch resistance, etc. are inferior. There is a problem that is difficult to use for the exterior parts of the parts, in particular the pressure of the thermal insulation rice cooker.

In order to solve the above problems, the present inventors have studied a method of obtaining a composition having excellent surface hardness and excellent heat resistance and gloss, and a composition having excellent moldability that does not reduce molding shrinkage rate and impact strength during injection molding of the composition. A study was also obtained to obtain.

The present inventors use high crystalline polypropylene having an isotactic pentad fraction of the boiling heptane insoluble portion of at least 0.96%, preferably at least 0.965%, or use a high proportion of the high crystalline polypropylene having a different melt index therein, It has been found that the above-mentioned conventional problems are solved by a polypropylene resin composition containing an appropriate amount of barium sulfate and talc having a specific particle size distribution and average particle size.

Accordingly, it is an object of the present invention to provide a novel high gloss polypropylene resin composition which provides an injection molded product having excellent surface hardness, heat resistance, gloss, moldability and the like.

The polyolefin resin composition of the present invention has a sediment having 55 to 89% by weight of a high crystalline polypropylene homopolymer having an isotactic pentad fraction of boiling-heptane insoluble portion of 0.96% or more and a melt index of 5 to 40 g / 10 minutes and an average particle size of 1.0 µm or less. It is characterized by containing 10 to 35% by weight of barium sulfate and 1 to 10% by weight of talc having an average particle size of 4 µm or less.

The resin used in the resin composition of the present invention is a highly crystalline polypropylene having a melt index of 5 to 40 g / 10 min at 230 ° C., and two resins having different fluidity at 5 to 12 g / 10 min and 20 to 27 g / 10 min, respectively. Different types of highly crystalline polypropylenes can also be used in combination.

When using a polypropylene resin having a melt index of 5g / 10min or less in the present invention, the resulting composition is relatively excellent in impact strength but low flow characteristics, making it difficult to manufacture large injection molded articles and low surface gloss of the molded article. On the other hand, when the polypropylene resin having a melt index of 40g / 10 minutes or more is excellent in flow characteristics, it is easy to adhere to the surface of the mold, and the surface glossiness of the molded product is excellent, but the impact strength is weak. On the other hand, when the polypropylene resin having excellent flow characteristics and the polypropylene resin having relatively high impact properties are mixed at a specific ratio, the impact property is excellent and the flowability is good, so that the surface glossiness can be easily adhered to the mold surface during injection molding. It is possible to obtain a resin composition that is excellent in heat and excellent in heat resistance.

The high crystalline polypropylene used in the present invention is specifically a homopolymer of propylene having high crystallinity, and a block copolymer of propylene and other monomers occupied most of the homopolymer of propylene having high crystallinity is also suitable. . Such polypropylene is preferably at least 0.96%, preferably at least 0.965%, of an isotactic pentad fraction of the boiling heptane insoluble portion used for the index of crystallinity. Here, the isotactic pentad fraction of the boiling heptane insoluble portion is determined by the boiling heptane insoluble portion of polypropylene. The fraction of propylene monomer units at the center of the chain of five consecutive meso-bonded propylene monomer units in pentad alone in a polypropylene molecule, according to the method published by A. Zambelli et al. (Macro molecules 6 925 1973). Refers to the measured value. The boiling heptane insoluble portion of the polypropylene is, for example, after completely dissolving the polymer in boiling xylene, lowering the temperature to 20 ° C. and leaving it to stand, and then separating and filtering the insoluble portion, drying the insoluble portion, and boiling it in a soxhlet extraction tube. It is obtained by a method such as performing heptane extraction.

The highly crystalline polypropylene used in the present invention is suitable according to any method, and generally is a Ziegler-Natta type stereospecific catalyst, a magnesium chloride-supported titanium chloride catalyst or a titanium trichloride modified stereospecific catalyst and triethylaluminum or dimethyl. It is preferable to obtain the polymerization by adding a cocatalyst such as aluminum to propylene or a mixture of this and another α-olefin. The polymerization method may be one obtained by polymerizing either a gaseous phase or a liquid phase. Further, the catalyst may be polymerized in an inert liquid or an active solvent, or may be one prepared by adjusting molecular weight by introducing hydrogen during polymerization, and the polymer obtained by molecular weight regulators such as organic peroxides.

In addition, in this invention, the said high crystalline polypropylene can also be used in mixture with another resin in the range which does not lose the effect of this invention. As such other resins, homopolymers of α-olefins such as ethylene, 1-butene, 1-pentene, 1-methylpentene-1, or the like, or block copolymers or random copolymers of such α-olefins and propylene, in addition to ordinary polypropylene, It is suitable. In such a case, the above-mentioned other resin is suitably blended at 40 parts by weight or less, preferably 25 parts by weight or less with respect to the weight part of the highly crystalline polypropylene.

The barium sulfate used in the resin composition of the present invention is preferably a precipitated type having an average particle size of 1.0 μm or less, and using a non-settled type or barium sulfate having an average particle size of 1.0 μm or more is not preferable because the surface gloss of a molded article is inferior. .

In addition, the barium sulfate used in the present invention may be surface-treated, and at this time, silane-based organic compounds such as silicon oil, silane coupling agent, and alcohol silanes may be exemplified as surface treatment agents. The surface treatment method may be any known method, and examples thereof include a Henschel mixer method. The amount of the surface treating agent is preferably 5% by weight or less with respect to barium sulfate, and when 5% by weight or more, the rigidity of the composition group obtained is rather lowered, which is not preferable.

The talc used in the resin composition of the present invention preferably has an average particle size of 4 μm or less, and when the talc having an average particle size of 4 μm or more is used, the surface gloss of the molded article is deteriorated and the Izod impact property is weak, which is not preferable.

In the present invention, talc may also use a surface treated in the same manner as barium sulfate. The use of surface-treated barium sulfate and talc improves the heat resistance and mechanical properties of the composition.

When the content of the polypropylene resin in the resin composition of the present invention exceeds 89% by weight, the heat resistance of the composition is lowered and the molding shrinkage rate is increased.When the content of the polypropylene resin is less than 55%, the fluidity of the composition is deteriorated and the appearance of the product is deteriorated and the composition is weak. It is not desirable because

When the content of barium sulfate in the resin composition of the present invention is less than 10% by weight, the heat resistance of the composition is low, and when it exceeds 35% by weight, it is not preferable because the fluidity of the composition is lowered and the composition becomes weak.

When the content of talc in the resin composition of the present invention is less than 1% by weight, the heat resistance of the composition is low and when it exceeds 10% by weight, the surface glossiness of the molded product is not preferable.

In the present invention, various additives such as antioxidants, ultraviolet absorbers, ultraviolet stabilizers, crystallization nucleating agents, anti-metal softening agents, organic pigments, inorganic pigments, etc., which are usually added to the polypropylene resin composition, are used within the scope of not losing the effects of the present invention. Or you may add together.

The resin composition of the present invention is obtained by premixing each of the above components with a Henschel mixer in advance, followed by melt kneading with a single screw or twin screw extruder to fillet the pellets. The pellets are used for various moldings such as extrusion molding and injection molding. It can be molded by the method.

The present invention will be described in more detail with reference to the following examples and comparative examples.

The evaluation method used in the Example and the comparative example was based on the test method described below.

* MI is measured according to ASTM D-1238, Izod impact strength is ASTM D-256, gloss is ASTM D-523, surface hardness is ASTM D-785, and heat distortion temperature is ASTM D-648.

Examples 1-7

Polypropylene resin HI500 (melt index: 10g / 10min) (Samsung Chemical), polypropylene resin HI700 (melt index: 27g / 10min) (Samsung Chemical), polypropylene resin HJ500 (melt index) : 10g / 10min) (Samsung General Chemicals) and polypropylene resin HJ700 (melt index: 27g / 10min) (Samsung General Chemicals), barium sulfate (SOLVAY, HD80) with an average particle size of 1.0 µm or less as a filler and 100% by weight of a mixture of talc (HAYASIKASEL, 5000P) having an average particle size of 4 μm or less according to the composition shown in Table 1 below, and 0.1% by weight of calcium stearate as CL-CAPTURER were irganox 1010 and arganese as an anti-myxing agent. 0.1% by weight, 0.1% by weight of ganox (IRGANOX) 168, 0.3% by weight of distearylthiopropinate (DSTDP) and 0.4% by weight of an antistatic agent (S-107A) were added to a mixer and mixed for 5 minutes. Extruded from Twin Scooter Extruder in the range of 180 ~ 210 ℃ and 80 ℃ Hot Air Dryer. After drying for 2 hours, to the results of the measurement according to the test methods described above to prepare a sample in a screw type injection molding machine it is shown in Table 1 below.

Comparative Examples 1 and 2

Except for using the polypropylene homopolymer having a melt index of 10g / 10min, 27g / 10min as the base resin in the content shown in Table 1 below, and was carried out as in Example 1, the results are shown in Table 1 Indicated.

Examples 8-11

Except for using the content of polypropylene resin, barium sulfate and talc as shown in Table 2 was carried out as in Example 1, the results are shown in Table 2 below.

Comparative Examples 3 to 10

As a filler, a precipitated barium sulfate (Hanol material, HPB-N) having an average particle size of 1.5 µm or less, a non-precipitated barium sulfate (Hol-M material, HB-M) having a particle size of 1.5 µm or less, talc (Ilshin, NA400) having a thickness of 10 µm or less is used. Except that was carried out in the same manner as in Example 3, the results are shown in Table 2 and Table 3.

Comparative Examples 11-13

Except for using the kind of barium sulfate and talc as the product shown in Table 3 as a filler was carried out in the same manner as in Example 3, the results are shown in Table 3 below.

Table 1

TABLE 2

TABLE 3

¹⁾ Component HC-A: Highly crystalline polypropylene homopolymer (melt index: 10g / 10min)

²⁾ Component HC-B: Highly crystalline polypropylene homopolymer (melt index: 27g / 10min)

³⁾ Component PP-A: Polypropylene homopolymer (melt index: 10g / 10min)

⁴⁾ Component PP-B: Polypropylene homopolymer (melt index: 27g / 10min)

⁵⁾ Component (A): precipitated barium sulfate (average particle size 1.0㎛)

⁶⁾ Component (B): non-settled barium sulfate (average particle size 1.5㎛)

⁷⁾ Component (C): precipitated barium sulfate (average particle size 1.5㎛)

⁸⁾ Component (D): Talc (Average particle size 4㎛)

⁹⁾ Component (E): Talc (average particle size 10㎛)

¹⁰⁾ Additives: 0.1% by weight of potassium stearate, 0.1% by weight of Irganox 1010,

                Arganox 168 0.1% by weight, DSTDP 0.3% by weight,

                S-107A 0.4 wt%

As in Examples 1 to 11, a molded article obtained by blending barium sulfate and talc having a characteristic average particle size with a specific high crystalline polypropylene resin as an inorganic filler is excellent in glossiness and has no deterioration in fluidity. Since the appearance is good and also has a very high heat resistance, it can be seen that it can be effectively used, for example, for exterior parts of a pressure thermostat rice cooker.

On the other hand, as in Comparative Examples 1 to 13, when the content and type of barium sulfate or talc as an inorganic filler in the conventional polypropylene resin is outside the scope of the present invention, high heat resistance and glossiness suitable for use in exterior parts of pressure cooker It can be seen that a good balance of surface hardness cannot be obtained.

Claims (1)

55-89% by weight of highly crystalline polypropylene homopolymer having an isotactic pentad fraction of boiling-heptane insoluble portion of not less than 0.96% and a melt index of 5-40 g / 10 minutes, and a precipitated barium sulfate having an average particle size of 1.0 µm or less 10-35 weight A polypropylene resin composition comprising% and 1 to 10% by weight of talc having an average particle size of 4 µm or less.