KR20120084412A - Low gravity polypropylene composition having excellent rigidity - Google Patents

Abstract

PURPOSE: A low-gravity polypropylene composition is provided to obtain rigidity and shock resistance by adding polypropylene to small content of aramide fiber. CONSTITUTION: A low-gravity polypropylene composition comprises 40-99.8 weight% of highly crystalline polypropylene resin in which isotactic peptard fraction is 96% or greater, 0.1-30 weight% of The highly crystalline polypropylene resin has a melt index of 1-100 g/10min. The Polymer is one or more selected from propylene 4 methyl 1 pentene copolymer, polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, and polylene 1 hexene copolymer.

Description

Low gravity polypropylene composition having excellent rigidity

The present invention relates to a polypropylene resin composition capable of lightening parts by securing high rigidity with low specific gravity, and more specifically, by adding aramid fibers having excellent rigidity and heat resistance as a reinforcing material to realize high rigidity. It relates to a low specific gravity high stiffness polypropylene resin composition which ensures excellent rigidity while securing impact resistance with the addition of a small amount compared to the reinforcing material.

Recently, the regulation of fuel efficiency of automobiles is rapidly increasing with respect to environmental problems, and accordingly, the demand for weight reduction and high performance is increasing. Accordingly, there is an increasing demand for weight reduction of plastic materials widely used in automotive parts, and in particular, the demand for low specific weight for polypropylene, which is rapidly increasing in demand compared to other plastic materials, continues to be continued.

However, conventional polypropylene resins, which have been used in automobile materials, have been limited in weight reduction due to an increase in specific gravity due to the addition of a large amount of inorganic reinforcing materials. Accordingly, in the present study, as a result of examining a reinforcing material capable of realizing high rigidity with a small amount of addition, a low specific gravity high stiffness polypropylene resin composition was developed through the addition of aramid fibers having excellent physical properties and heat resistance to high stereoregular polypropylene. .

Until now, there was no polypropylene resin composition in which aramid fibers were added in Korea, and modification of polypropylene by adding polyamide (nylon) was examined in Korean Patent Publication No. 1998-0066165, and in 1999-0012192, a resin composition for electromagnetic wave shielding. As a base for adding conductive metal powder for shielding electromagnetic waves, aramid fiber sheet was used, but it was the first time that it was used as a functional reinforcing material for modifying the properties of polypropylene.

The present invention is to solve the problems of the prior art as described above, an object of the present invention by adding a small amount of aramid fibers to high crystalline polypropylene excellent in rigidity to ensure the rigidity required as a vehicle material low specific gravity Its purpose is to develop lightweight materials.

The present invention is to solve the above problems, 40 ~ 99.8% by weight of highly crystalline polypropylene resin (HIPP), 0.1-30% by weight of aramid fibers and commercialization of isotactic peptide content by C-NMR method more than 96% It provides a low specific gravity high rigid polypropylene resin composition comprising 0.1 to 30% by weight.

In one embodiment of the invention, the high crystalline polypropylene resin has a melt index of 1 ~ 100g / 10min, polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer and propylene 4 methyl It may be at least one polymer selected from the group consisting of 1 pentene copolymer.

In one embodiment of the present invention, the aramid fiber has a specific gravity of 1.43g / cm ³ , the length may be in the range of 1.0 ~ 3.0mm.

In one embodiment of the present invention, the compatibilizer may be a modified polypropylene or organosilane compound.

In one embodiment of the present invention, the modified polypropylene may be a modified propylene homopolymer, ethylene / propylene copolymer or propylene / alpha-olefin nonconjugated diene compound copolymer by unsaturated carboxylic acid or derivatives thereof.

In one embodiment of the present invention, the organosilane compound is gamma-aminopropyltriethoxysilane, alpha- glycidoxy propyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Beta-methacryloxypropyltrimethoxysilane, alpha-aminopropyltriethoxysilane, N-beta- (aminoethyl) -alpha-aminopropyltrimethoxysilane and N-beta- (aminoethyl) -alpha-amino It may be at least one selected from the group consisting of propylmethyldiethoxysilane.

According to the present invention, by providing a low specific gravity polypropylene resin composition with improved rigidity and impact resistance, it is suitable for use as a material for parts requiring weight reduction, such as automotive interior materials.

The present invention is 40 to 99.8% by weight of a high crystalline polypropylene resin (HIPP) having an isotactic peptide content by C-NMR method of 96% or more, 0.1 to 30% by weight of aramid fibers and 0.1 to 30% by weight of a compatibilizer It provides a low specific gravity high rigid polypropylene resin composition comprising.

If the isotactic peptide content of the highly crystalline polypropylene resin of the present invention is less than 96%, mechanical properties such as strength, impact resistance, heat resistance and rigidity of the polypropylene resin are deteriorated, which is not preferable.

The content of the high crystalline polypropylene resin (HIPP) of the present invention is preferably 40 to 99.8% by weight, but less than 40% by weight is not preferable because it is difficult to process, and if the content of the reinforcing material is 99.8% by weight or more, It is weak and the strength improvement effect is low, which is not preferable.

The The melt index of the highly crystalline polypropylene resin is 1-100 g / 10 min, and is selected from the group consisting of polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer and propylene 4 methyl 1 pentene copolymer. It may be one or more polymers selected.

If the melt index is less than 1g / 10min, the injection moldability is lowered, so productivity is lowered, and if it exceeds 100g / 10min, the mechanical properties such as impact strength are lowered, which is not preferable.

In the present invention, the specific gravity is 1.43 g / cm ³ , and the length of the aramid fibers in the range of 1.0 to 3.0 mm is added to ensure balance between rigidity and impact characteristics.

The content of the aramid fiber used in the present invention is preferably used in the range 0.1 to 30% by weight, less than 0.1% by weight is not preferable because the filling effect of the inorganic material is weak compared to the general PP, if the content exceeds 30% by weight This decreases and the cost rises sharply, which is undesirable.

The compatibilizer included in the composition of the present invention is used for improving the kneading property of polypropylene and aramid fibers, and specifically, a modified polypropylene or an organosilane compound is preferable.

The content of the compatibilizer is preferably 0.1 to 30.0% by weight.

Compatibilizer If the content is less than 0.1% by weight can not sufficiently maintain the interfacial adhesion between the aramid fibers and the polypropylene resin, there is no physical property improvement effect, when the content exceeds 30.0% by weight no further physical property improvement effect.

The modified polypropylene may be a modified propylene homopolymer, ethylene / propylene copolymer or propylene / alpha-olefin nonconjugated diene compound copolymer by unsaturated carboxylic acid or derivatives thereof.

In addition, the modification method is not particularly limited and may be modified using conventionally known methods. The unsaturated carboxylic acid used for the modification may be acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, ditraconic acid, sorbic acid, phosphoric acid, and the like, maleic anhydride, itaconic anhydride, ditraconic anhydride, and the like. Methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, monoether maleate / ester, acrylamide, monoamide maleic acid, N-butyl maleimide, sodium acrylate, sodium methacrylate, and derivatives thereof.

Specific examples of the organosilane compound include gamma-aminopropyltriethoxysilane, alpha-glycidoxyoxytrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, beta-meth Krilloxypropyltrimethoxysilane, alpha-aminopropyltriethoxysilane, N-beta- (aminoethyl) -alpha-aminopropyltrimethoxysilane or N-beta- (aminoethyl) -alpha-aminopropylmethyldie Oxysilanes.

Inorganic pigments and organic pigments that can be added for color, various additives that can be added as stabilizers, for example, long-term heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents (SLIP agents), nucleating agents It is possible to add etc. in the range which does not deviate from the objective of this invention.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example

Examples 1-2 and Comparative Examples 1-2

The polypropylene resin compositions of Examples 1-2 and Comparative Examples 1-2 were manufactured with the composition shown in Table 1 using the component described below.

1) Polypropylene: Highly crystalline homopolypropylene with an isotactic peptide content of 96% or more, Samsung Total, Melt Index (MI): 25g / 10min

2) Aramid fiber: Aramid fiber, specific gravity: 1.43g / cm ³ , length: 1.3 ~ 2.3mm

3) Inorganic filler: talc, KoCH, specific gravity 2.7, diameter 3 ~ 4 ㎛

4) Compatibilizer: CP4673, Samsung Total (maleic anhydride graft PP, MI = 100g / 10min)

Furtherance Comparative Example-1 Comparative Example-2 Example-1 Example-2 Polypropylene 100 90 92 86 Aramid fiber 8 8 Inorganic filler 10 Compatibilizer 6

After dry blending the above components with a Henschel mixer, all of them were added to the hopper of the JSW TEX44 Alpha (ALPHA) twin-screw kneading extruder at once and melt kneaded together to produce a copper resin composition, followed by Samsung Kleukner FCM-110 (clamping force = 110). Ton) was used to measure the flexural strength specified in ASTM D790 standard and Izod impact strength measured in ASTM D256 standard by injection molding method.

Next, as a result of measuring the mechanical properties of the specimens specified in the ASTM standard, it was confirmed that the mechanical properties, in particular stiffness and impact balance is very good. The measurement results are shown in Table 2 below.

[Property evaluation method]

1) Density

It was measured at room temperature (23 ℃) by the method of ASTM D1505.

2) tensile strength and elongation

It was measured at room temperature by the method of ASTM D638.

3) Flexural modulus

It was measured at room temperature by the method of ASTM D790.

4) Izod impact strength

It was measured at room temperature by the method of ASTM D256.

5) Heat Deflection Temperature (HDT)

It was measured at room temperature by the method of ASTM D648.

Recipe Table Comparative Example-1 Comparative Example-2 Example-1 Example-2 Density g / cm3 0.91 0.97 0.92 0.93 Tensile Strength (Yield) kg / cm2 380 340 430 470 Flexural modulus kg / cm2 17,500 22,000 20,930 22,500 Izod Shock (Notched, 23 ℃) kg cm / cm 2.5 3.5 4.5 5.0 HDT ℃ 115 125 133 137

From the results of evaluation of physical properties, as shown in Example-1, the resin composition to which the aramid fiber was basically added showed a significant improvement in stiffness, impact strength, heat resistance, etc., compared to the additive-free product of Comparative Example-1. In the case of Example 2, it can be seen that the improvement effect is much larger. In addition, it can be seen that the impact strength and the heat resistance are significantly improved while securing the flexural modulus of the equivalent level or more at a low specific gravity with the addition of a smaller amount than the talc of Comparative Example-2. Therefore, by utilizing the aramid fibers, it was possible to secure an optimal resin composition for interior materials by developing low specific gravity, high rigidity and high heat resistant materials.

Claims (6)

Low specific gravity, including 40-99.8 wt% of high crystalline polypropylene resin (HIPP) having an isotactic peptide content by C-NMR method of 96% or more, 0.1-30 wt% of aramid fibers and 0.1-30 wt% of a compatibilizer Rigid polypropylene resin composition. The method of claim 1, wherein the high crystalline polypropylene resin has a melt index of 1 ~ 100g / 10min, polypropylene homopolymer, propylene-ethylene copolymer, propylene 1 butene copolymer, propylene 1 hexene copolymer and propylene 4 methyl 1 pentene Low specific gravity high stiffness polypropylene resin composition, characterized in that at least one polymer selected from the group consisting of copolymers. The low specific gravity high stiffness polypropylene resin composition according to claim 1, wherein the aramid fiber has a specific gravity of 1.43 g / cm ³ and a length of 1.0 to 3.0 mm. The low specific gravity high rigid polypropylene resin composition according to claim 1, wherein the compatibilizer is a modified polypropylene or an organosilane compound. The method of claim 4, wherein the modified polypropylene is low specific gravity, characterized in that the modified propylene homopolymer, ethylene / propylene copolymer or propylene / alpha-olefin non-conjugated diene compound copolymer by unsaturated carboxylic acid or derivatives thereof. Rigid polypropylene resin composition. The compound according to claim 4, wherein the organosilane compound is gamma-aminopropyltriethoxysilane, alpha-glycidoxyoxytrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, beta- Methacryloxypropyltrimethoxysilane, alpha-aminopropyltriethoxysilane, N-beta- (aminoethyl) -alpha-aminopropyltrimethoxysilane and N-beta- (aminoethyl) -alpha-aminopropylmethyl Low specific gravity high stiffness polypropylene resin composition, characterized in that at least one member selected from the group consisting of diethoxysilane.