KR100634223B1 - High rigidity resin composition having good flowability and impact strength - Google Patents

Abstract

The present invention relates to a highly rigid polypropylene resin composition having excellent flowability and impact resistance, and more particularly, fluidity characterized in that an inorganic nucleating agent is added in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of a high stereoregular polypropylene resin. And it relates to a high rigid polypropylene resin composition excellent in impact resistance.

Description

High rigidity polypropylene resin composition excellent in fluidity and impact resistance {HIGH RIGIDITY RESIN COMPOSITION HAVING GOOD FLOWABILITY AND IMPACT STRENGTH}

The present invention relates to a highly rigid polypropylene resin composition having excellent flowability and impact resistance, and more particularly, by adding an inorganic nucleating agent to a high-stereoregular polypropylene resin, and more particularly in terms of fluidity and impact resistance compared to existing polypropylene resin compositions. The present invention relates to a resin composition having improved rigidity.

Polypropylene resin is excellent in rigidity, chemical resistance, and moldability compared to other polyolefin-based materials, and thus has a wide industrial application range for automobile interior parts and home appliance parts. The reason why polypropylene resin is widely used as a polyolefin resin for injection molding is that polypropylene resin has superior rigidity, hardness, tensile strength, and heat resistance compared to polyethylene resin. There are many techniques for increasing the rigidity and heat resistance of polypropylene resins for use in high temperature environments. In particular, in automobiles and electrical and electronic parts applications requiring high heat resistance, a method of reinforcing rigidity and heat resistance by mixing an inorganic filler with polypropylene resin has been proposed. In this regard, Japanese Patent Nos. 53-64256 and 53-64257 Nos. 57-55952 and the like have been disclosed to improve the mechanical properties by blending polypropylene with inorganic fillers and rubber, but problems such as poor appearance due to inorganic fillers, cost incurred due to the increase in specific gravity of the material have.

In addition, when the inorganic filler is generally added, the fluidity of the resin may be deteriorated during molding, thereby increasing the possibility of problems such as poor dispersion of pigments and unmolding of complex products.

In order to solve this drawback, European Patent No. 562119 and Japanese Patent No. 522078 have developed a resin composition which improves rigidity and heat resistance by adding a phosphorus-based nucleating agent to a polypropylene resin without filling an inorganic material. Genie has a disadvantage in that heat resistance is inferior to inorganic filled polypropylene due to its low heat resistance.

There are several methods to improve the impact properties of polypropylene, one of which is widely used by melt-mixing rubber-based materials such as ethylene propylene copolymer (EPM) or ethylene propylene diene copolymer (EPDM) to polypropylene. It has been. However, in this case, the uniform distribution of EPM or EPDM can be a problem, and the price rises.

Another method is to copolymerize α-olefins, such as ethylene, during propylene polymerization. In this case, the impact properties increase as the ethylene content increases, but the rigidity and heat resistance decrease. Not suitable for receiving

The object of the present invention is to improve the above problems, good flowability during molding, excellent impact resistance, high fluidity and impact resistance that can be applied to heat-resistant electrical and electronic parts and home appliances applications can be used at high temperatures It is to provide a rigid high-stereoregular polypropylene resin composition.

The highly rigid polypropylene resin composition of the present invention is characterized in that the inorganic nucleating agent is added in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the high-stereoregular polypropylene resin.

In the highly rigid polypropylene resin composition of the present invention, the polypropylene resin is a high-stereoregular polypropylene having a wide molecular weight distribution, and the molecular weight distribution is 7-12 by gel permeation chromatography (GPC) method, and the three-dimensional structure of the nuclear magnetic resonance method. The regularity index is preferably 96% or more based on the pentad method, and the melt index (MI) is 3 to 30 g / 10 minutes (ASTM, 230 ° C). If the molecular weight distribution of the polypropylene is less than 7, the flowability is deteriorated, which may cause unmolding and poor surface appearance during injection molding of a product having a complicated shape such as a grill. In addition, if the flowability worsens, a large amount of pressure is left on the product when it is injected, and a lot of residual stress is left. When the product is used at a high temperature, warpage and distortion occur in the product. In addition, when the molecular weight distribution of polypropylene exceeds 12, the time for injection molding is too long to reduce the overall production speed, and the product contains a large amount of low molecular weight polypropylene resin. This will greatly harm the appearance.

If the stereoregularity index of the polypropylene is less than 96%, there is a disadvantage in that the heat resistance of the polypropylene resin is lowered. The higher the stereoregularity index is, the higher the heat resistance is and the mechanical strength is increased. Three-dimensional rules also have no special disadvantages due to the increased index.

In addition, when the melt index of polypropylene is less than 3g / 10min, productivity decreases due to poor moldability during injection molding.However, when the melt index exceeds 30g / 10min, the impact strength is sharply lowered, thus the value as a product. Is lowered.

In the highly rigid polypropylene resin composition of the present invention, the inorganic nucleating agent is not particularly limited to organometallic nucleating agent, talc nucleating agent and the like. The organometallic nucleating agent may be aluminum parabutyl benzoic acid, sodium benzoic acid, calcium benzoic acid, or the like as a nucleating agent including components such as Al, Mg, Ti, Zn, Ca, P, and Si in the structure. The organometallic nucleating agent is added in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the polypropylene polymer of the entire resin composition. When the content of the nucleating agent is 0.05 parts by weight or less, it is difficult to obtain sufficient heat resistance. Do not. Talc nucleating agent may be preferably used talc having an average particle diameter of 2.0μ and a maximum particle size of 6μ or less, and when 6μ or more, the nucleating agent efficiency is lowered. The amount of talc nucleating agent added is preferably 0.05 to 0.5 parts by weight based on 100 parts by weight of the polypropylene polymer of the entire resin composition, and it is difficult to obtain sufficient rigidity and heat resistance when the content is 0.05 parts by weight or less, and the effect improvement is no longer at 0.5 parts by weight or more. It is not expressed.

To the polypropylene resin composition of the present invention, various conventional additives such as antioxidants, heat stabilizers, weather stabilizers, antistatic agents, lubricants, pigments, dyes, and the like may be added within a range not departing from the characteristics of the present invention.

There is no restriction | limiting in particular in the method of manufacturing the polypropylene resin composition of this invention, The method of manufacturing the polypropylene resin composition generally known can be used. Each of the above components can be freely selected and mixed according to the desired order. Usually, by adding necessary amounts of each of the above components and other additives, a kneader such as a kneader, a roll, a short-barrier mixer, and a single or twin screw extruder are used. By kneading can be used.

The present invention can be understood in more detail by the following examples, the following examples are only examples for illustrating the present invention and are not intended to limit the protection scope of the present invention.

Examples and Comparative Examples

Put all the ingredients in Table 1 in the following PCM30 twin-screw kneading extruder and kneaded to prepare a polypropylene resin composition, and then injected into Samsung Kleukner FCM-110 (clamping force = 110 tons) specimens determined by ASTM standards Was prepared and its physical properties were measured. The results are shown in Table 1.

Test conditions for each test property are as follows.

1) Melt Index

Based on D1238, it measured by 2.16Kg load at 230 degreeC.

2) spiral flow

It was measured by the test method of Samsung General Chemicals itself, and the measurement conditions are as follows.

Injection molding machine → 110 tons (9.2oz)

Shape of injection channel → semicircle (cross section)

Feeding part temperature → 215 ℃

Cylinder and nozzle temperature → 235 ℃

Mold temperature → 50 ℃

Cooling time → 10 seconds

Injection speed → 15 mm / s

Injection pressure → 1000 kg / ㎠

Measurement item → Measurement of the flow length of the spiral specimen injected under the above conditions

3) Flexural modulus

It measured based on D790.

4) Izod impact strength

It measured at 23 degreeC based on D256.

5) Heat Deflection Temperature

It was measured under low load (4.6Kg) based on D648.

Table 1

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3  Configuration Polypropylene 1 100 100 100 - - Polypropylene 2 - - - 100 - Polypropylene 3 - - - - 100 Inorganic nucleating agent 0.3 0.5 - 0.5 -  Properties Melt Index (g / 10min) 5.0 5.0 5.0 5.0 5.0 Spiral Flow (cm) 100 100 100 75 75 Flexural modulus (kgf / ㎠) 22,000 23,000 19,000 18,500 13,000 Izod impact strength (kg, cm / cm) 5.0 5.0 4.5 3.5 7.0 Heat Deflection Temperature (℃) 140 140 120 125 105

(week)

1) Polypropylene 1: Highly crystalline polypropylene homopolymer having a melt index (MI) of 5 g / 10 min (230 ° C.), nuclear magnetic resonance pentad method stereoregularity index of 97% and molecular weight distribution of 8.0

2) Polypropylene 2: Polypropylene homopolymer with a melt index of 5g / 10 min (230 ° C), nuclear magnetic resonance pentad method stereoregularity index of 91% and molecular weight distribution of 5.5

3) Polypropylene 3: propylene ethylene block copolymer having a melt index of 5 g / 10 min (230 ° C.), nuclear magnetic resonance pentad method stereoregularity index of 91%, molecular weight distribution of 5.5, and ethylene content of 5 parts by weight

4) Inorganic nucleating agent: Talc nucleating agent with an average particle diameter of 2.0μ and a maximum particle diameter of 6μ or less

As can be seen from the results in Table 1, Example 1 has a higher flexural modulus and heat deflection temperature than Comparative Example 1 without using an inorganic nucleating agent.

And Example 2 is excellent in flowability compared to Comparative Example 2, the stiffness, impact strength, heat deformation temperature is high. In Comparative Example 2, since the flowability is poor, injection workability is inferior, and a large amount of pressure is applied when molding.

In the case of Example 1 and Comparative Example 3, Comparative Example 3 is excellent in impact strength but poor in flowability, flexural modulus and heat resistance, and is not suitable for use in a product used at high temperature.

As can be seen from the above, the polypropylene resin composition prepared according to the present invention has excellent flowability, good heat resistance, good rigidity, and excellent impact strength compared to the conventional homopolypropylene resin, and thus these performances are complex. It is suitable for the application of microwaves, coffee makers, irons, etc. that require high heat.

Claims (4)

High-stereoregular polypropylene resins having a melt index of 3 to 5 g / 10 min, molecular weight distribution measured by gel permeation chromatography, and a solid regularity index of 96% or more based on the pentad method based on the nuclear magnetic resonance method. A polypropylene resin composition comprising 0.05 to 0.5 parts by weight of an inorganic nucleating agent added to 100 parts by weight. The polypropylene resin composition according to claim 1, wherein the inorganic nucleating agent is an organometallic nucleating agent or talc nucleating agent such as aluminum parabutyl benzoic acid, sodium benzoic acid or calcium benzoic acid. The polypropylene resin composition according to claim 2, wherein the talc nucleating agent is talc having an average particle diameter of 2.0 mu and a maximum particle diameter of 6 mu or less. The polypropylene resin composition according to claim 1, further comprising conventional additives such as antioxidants, heat stabilizers, weather stabilizers, antistatic agents, lubricants, pigments, and dyes.