KR20010054822A - Polypropylene resin composition having thermal resistance, high rigidity and low warpage properties - Google Patents

Abstract

PURPOSE: Provided is a small warping polypropylene resin composition excellent in a heat-resistance and a strength, which contains a polypropylene resin and an organosilane compound and can be used as a part of fans. CONSTITUTION: The polypropylene resin composition comprises 100pts.wt. of a polypropylene resin composition comprising 20-69wt% of polypropylene, 1.0-30wt% of a modified polypropylene which is modified by an unsaturated carboxylate or derivatives thereof, 30-50wt% of glass fiber and mica as an inorganic filler and 0.01-2.0pts.wt. of the organosilane compound. The polypropylene is crystalline isotactic propylene-only polymer and has a melt index of 5-70g/10min(230deg.C).

Description

Low warpage polypropylene resin composition excellent in heat resistance and rigidity {POLYPROPYLENE RESIN COMPOSITION HAVING THERMAL RESISTANCE, HIGH RIGIDITY AND LOW WARPAGE PROPERTIES}

The present invention relates to a polypropylene resin composition having excellent rigidity and heat resistance compared to conventional polypropylene resins, and having significantly improved low warpage. More specifically, the present invention relates to a polypropylene resin, an organosilane compound, an acid-modified polypropylene polymer, and an inorganic filler. The present invention relates to a polypropylene resin composition having excellent heat resistance and rigidity, including glass fiber.

Polypropylene resin has excellent mechanical properties, chemical resistance, and moldability, and has a wide range of industrial applications such as automotive interior parts and home appliance parts. However, polypropylene exhibits non-polarity in the chemical structure of the molecule, which is inferior in secondary workability, especially in solid state, paintability and adhesion to other materials, and poor dimensional stability due to the crystalline structure. It is somewhat inferior to other resins, such as polystyrene and styrene acrylonitrile copolymers, which are competitively applied as product materials. Accordingly, a method of developing a material in which an inorganic filler or a resin is blended with a polypropylene resin for automobiles and electric and electronic parts has been proposed.

In this regard, Japanese Patent Publications No. 64-87645 and Japanese Patent Publication Nos. 1- 174550 are disclosed in blending polystyrene with a styrene butadiene block copolymer, a compatibilizer, to improve mechanical strength, heat resistance and paintability. Although, the improvement of mechanical properties is very low and it is not suitable for application as a general purpose material using a relatively expensive compatibilizer.

In Japanese Patent Application Laid-Open No. 3-126740, a resin composition in which a nylon resin having excellent heat resistance to polypropylene resin and a glass fiber having a large effect of improving strength and heat resistance among inorganic fillers is blended with acid-modified polypropylene. The composition has a merit that can be used even at 150 to 170 ° C by using a nylon resin having a lower viscosity than polypropylene, so that the matrix of the prepared resin composition becomes a nylon resin. However, it has excellent rigidity, paintability, chemical resistance and heat resistance, but has a limitation as a general-purpose material because expensive nylon resin is used.

On the other hand, in order to improve rigidity, heat resistance and other mechanical properties, polypropylene resins are used as inorganic fillers, needle-like fillers such as glass fibers, carbon fibers and whiskers, plate-like fillers such as meteorites and talc, spherical types such as calcium carbonate and alumina, etc. Filler is used. In particular, polypropylene resin filled with glass fibers is mainly used for products requiring high rigidity and high heat resistance.

Due to the high aspect ratio fibrous structure, glass fiber has an excellent effect of improving mechanical properties compared to other spherical or plate-shaped inorganic fillers.

In general, the rigidity and heat resistance of the glass fiber in polypropylene resin are improved, but the rigidity and heat resistance of the glass fiber increase, but the shrinkage difference between the flow direction and the flow direction after molding the product increases, causing warpage of the final molded product. And there is a limit to the application to the rotor parts (fans) that require high dimensional stability and has the disadvantage of poor appearance. The larger the product, the greater the warpage (deformation).

There is a plate-shaped mica as a filler to minimize the occurrence of the above-described warpage, to achieve a relatively good rigidity and good appearance. Mica is relatively inexpensive and has various colors of materials (gray, white, yellow, dark brown), and is highly applicable to various electric and automotive materials without coloring, while needle type fillers in tensile strength, flexural strength, Izod impact strength, and heat resistance It is inferior and has a low bulk density of the filler, which makes it difficult to feed raw materials in the kneader when producing a composition having a high filler content (eg, 40% or more), thereby degrading workability and productivity.

An object of the present invention is a polypropylene resin composition filled with glass fiber and mica which is excellent in heat resistance and rigidity, and at the same time has a low warpage (strain), which can be applied to automobile parts or electric and electronic parts in order to solve the above problems. To provide.

The polypropylene resin composition of the present invention comprises 20 to 69% by weight of polypropylene, 1.0 to 30% by weight of modified polypropylene modified by unsaturated carboxylic acid or derivatives thereof, and 30 to 50% by weight of glass fiber and mica as an inorganic filler. 0.01 to 2.0 parts by weight of an organosilane compound, based on 100 parts by weight of a polypropylene resin composition (hereinafter, referred to as a base resin composition).

In the polypropylene resin composition of the present invention, the polypropylene is preferably an isotactic polypropylene polymer having a melt index (MI) of 5 to 70 g / 10 min (ASTM D1238, 230 ° C) and having crystallinity. If the melt index is less than 5g / 10min, the moldability of the parts is not good, the productivity is lowered, while if the melt index exceeds 70g / 10min, the impact strength is sharply lowered.

In the polypropylene resin composition of the present invention, the modified polypropylene is obtained by modifying polypropylene with an unsaturated carboxylic acid or a derivative thereof. Examples of polypropylene are polypropylene homopolymers, ethylene / propylene copolymers, propylene / α-olefin nonconjugated diene compound copolymers such as EPDM. Examples of the α-olefins include ethylene, butene-1, heptene-1, hexene-1, and 4-methylpentene, and these may be used alone or in combination of two or more thereof. Unsaturated carboxylic acids for modifying the polypropylene include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, ditraconic acid, sorbic acid, phosphoric acid, and the like. Anhydrides, esters, amides, imides, metal salts and the like, examples of which are maleic anhydride, itaconic anhydride, ditraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoether / ester, acrylic Amide, maleic acid monoamide, N-butyl maleimide, sodium acrylate, sodium methacrylate, and the like, and these may be used alone or in combination of two or more thereof.

The method of modifying the polyolefin is a method of kneading the polypropylene by dissolving the polypropylene in a suitable organic solvent and adding an unsaturated carboxylic acid or a derivative thereof and a radical generator, or performing graft copolymerization for each of the above components using an extruder. The method can be used.

In the polypropylene resin composition of the present invention, the amount of the modified polypropylene is preferably 0.1 to 10% by weight of an unsaturated carboxylic acid or a derivative thereof that is a modifier. If it is less than 0.1% by weight, it is difficult to express the effect as a compatibilizer, and when it is mixed in a large amount of more than 10% by weight, a large amount of unreacted denaturant remains in polypropylene, and melt-kneading mica or glass fibers in a batch to produce a polypropylene resin composition. When the unreacted denaturant is sublimed and stays in the air, an irritating odor is generated to deteriorate the working environment. In addition, there is a problem that the obtained polypropylene resin composition is colored yellowish-brown and lowers the merchandise value.

The content of the modified polypropylene is preferably 1.0 to 30% by weight based on the total weight of the base resin composition. If the content of the modified polypropylene is less than 1.0% by weight, the interfacial adhesion between the filler and the polypropylene resin cannot be sufficiently maintained, and there is no contributing to the improvement of the physical properties. It doesn't work.

In the polypropylene resin composition of the present invention, as the inorganic filler, glass fiber and mica are used, and in the case of glass fiber, an average particle diameter of 5-15 μm, preferably 9-13 μm, and a length of 1-16 mm Can be used. When the average particle diameter of the glass fiber is less than 5 μm, it is broken during mixing and the rigidity is weak. When the average particle diameter of the glass fiber is more than 15 μm, the mechanical strength cannot be obtained, the deformation of the molded article is deteriorated, and the appearance is deteriorated. In the present invention, the length of the glass fiber is not limited to a specific length can be used commercially available, it is preferable in terms of kneading workability when using a chopped strand (length of about 1 ~ 8 mm).

In the polypropylene resin composition of the present invention, mica is an aluminosilicate containing alkali metals such as potassium, magnesium, aluminum, and iron, and is generally used as a filler, reinforcing material, and the like of a resin. Mica may include white mica (muscobite), gold mica (flogoite), biotite (biotite), sodium carbonate mica, silk mica, iron mica, vanazin mica, and the like. All kinds of commercially available mica can be used, with a material having an average particle diameter of 10 to 500 µm, particularly 50 to 250 µm. If the average particle diameter of mica is less than 10㎛, heat resistance and rigidity cannot be obtained, and if it exceeds 500㎛, mica particles are observed with the naked eye, and thus appearance is poor.

The content of the inorganic filler is preferably 30 to 50% by weight, which is an appropriate amount for use, based on the total weight of the base resin composition by adding glass fiber and mica, and less than 30% by weight is insufficient to achieve the desired effect, and exceeds 50% by weight. It is disadvantageous in terms of dispersibility and appearance with the lower surface resin. In addition, the content of glass fiber in the total inorganic filler is preferably not more than 45% by weight. If the content of glass fiber is more than 45% by weight, the appearance of the molded article is deteriorated and workability is exerted during the manufacture of extrusion kneading of copper material. Falls out.

Preferably, the mixing weight ratio of glass fiber and mica is preferably glass fiber: mica = 1: 0.5 to 8, and when the ratio of mica is less than 0.5, there is no warpage preventing effect of the copper resin composition, In this case, the glass fiber content is relatively low, and the high rigidity desired to be obtained is not expressed.

In the polypropylene resin composition of the present invention, the organosilane compound is not particularly limited. Examples include gamma-aminopropyltriethoxysilane, alpha-glycidoxyoxytrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, beta-methacryloxypropyltrimethoxysilane , Alpha-aminopropyltriethoxysilane, N-beta- (aminoethyl) -alpha-aminopropyltrimethoxysilane, N-beta- (aminoethyl) -alpha-aminopropylmethyldiethoxysilane and the like can be used. . In particular, an aminosilane compound containing one or two amino groups is preferable in the present invention.

The organosilane compound is blended in an amount of 0.01 to 2.0 parts by weight, which is an appropriate amount in use, for the effect of improving physical properties with respect to 100 parts by weight of the base resin composition, and particularly preferably a blending ratio of 0.05 to 1.0 parts by weight.

In the polypropylene resin composition of the present invention, ordinary additives such as reinforcing materials, fillers, heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, flame retardants, pigments, dyes, etc. do not deviate from the characteristics of the present invention. And specific examples thereof include talc, carbon fiber, calcium carbonate, clay, silica, alumina, carbon black, magnesium hydroxide, zeolite, barium sulfate and the like.

In the method for producing the resin composition of the present invention, kneading using a single screw or twin screw extruder is preferable, and it is possible to mix at a polypropylene melting point or higher using processing conditions for producing a polypropylene resin composition which is commonly known. However, it is essential that the glass fibers and mica are simultaneously or separately introduced during the extruder to sufficiently maintain the shape of the filler.

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

Table 1 shows the contents of the components of Examples 1 to 3 and the physical properties of the prepared resin compositions according to the examples.

Description of each component used in Examples 1-3 and Tables 1-4 of Table 1 is as follows.

1) Polypropylene: Polypropylene homopolymer with a melt index (MI) of 10 g / 10 min (230 ° C.)

2) Inorganic fillers:

Glass fibers: Aminosilane surface-treated fibers with an average particle diameter of 11 μm and a length of 3 mm

-Mica: Brown tank light mica with an average particle diameter of 250 μm (no surface treatment, mica (1)), brown tank light mica with an average particle diameter of 60 μm (no surface treatment, mica (2))

3) Modified polypropylene: A polypropylene homopolymer having a melt index of 110 g / 10 minutes, containing 0.2% by weight or more of reacted maleic anhydride based on the weight of polypropylene.

4) Organosilane Compound: An aminosilane compound containing one or two amino groups

In the ingredients and blending ratios of Table 1, polypropylene, modified polypropylene, organosilane compounds and additives were dry blended with a Henschel mixer in a JSW TEX44 Alpha (ALPHA) twin-screw kneading extruder, and all were added to the main hopper at once. Glass fiber is fed by weight feeder in the extruder and melt kneaded to produce the same resin composition, and then injected into Samsung Klockner FCM-110 (110 tons of clamping force) to produce specimens specified by ASTM standards. Izod impact strength, tensile strength, elongation, flexural modulus, shrinkage and dimensional stability were measured.

Test conditions for each test property are as follows.

1) Heat Deflection Temperature

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

2) Izod impact strength

The V notched specimens were measured at room temperature based on D256.

3) Tensile strength and elongation

It was measured at room temperature based on D638.

4) Flexural modulus

It measured at room temperature based on D790.

5) Shrinkage rate (degree of deflection / deformation)

Sheets having a thickness of 2 mm and widths of 100 mm each were injection molded, and the dimensions of the flow direction and the perpendicular direction were measured after the lapse of time at room temperature and humidity of 50%.

Table 1

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Polypropylene 660 660 560 700 600 600 650 Fiberglass 100 100 200 - - - 300 Mica (1) 200 200 200 300 400 - - Mica (2) - - - - - 400 - Modified polypropylene 40 40 40 - - - 50 Organosilane Compound (1) 0.3 0.15 0.3 - - - - Organosilane Compound (2) 0.1 0.05 0.1 - - - - Organosilane Compound (3) - 0.1 - 0.3 0.3 0.3 - Measurement result Heat deflection temperature (℃) 160 162 162 145 146 147 161 Tensile strength (kgf / ㎠) 570 570 730 358 367 366 780 % Elongation <10 <10 <10 <10 <10 <10 <10 Flexural modulus (kgf / ㎠) 60,000 61,000 79,000 56,000 64,000 62,000 58,000 Impact Strength (kgf, cm / cm) 4.7 4.7 5.8 4.1 3.3 3.2 8.1 Shrinkage (MD / TD), 1 / 000mm 4.0 / 6.0 4.0 / 6.0 3.0 / 5.0 8.0 / 9.0 7.0 / 8.0 7.0 / 8.0 2.0 / 7.0 Dimensional stability (low warpage) O O O ◎ ◎ ◎ ×

(week)

Organosilane Compound (1): Alpha-Aminopropyltrimethoxysilane

Organosilane Compound (2): Beta-methacryloxypropyltrimethoxysilane

Organosilane Compound (3): Gamma-Aminopropyltriethoxysilane

(◎: State with no warpage, O: State with little warpage, X: State with large warpage due to large difference in shrinkage in the horizontal and vertical directions)

As can be seen from Table 1, Examples 1 to 3 according to the present invention had a higher heat deflection temperature, a higher tensile strength, flexural strength and impact strength, and a smaller shrinkage rate than Comparative Examples 1 to 3, respectively. In addition, the dimensional stability was very good. Comparative Example 4 was inferior in dimensional stability to the Example.

As can be seen from the above, the polypropylene resin composition prepared according to the present invention not only has excellent mechanical properties such as rigidity and heat resistance, but also has low warpage and deformation, which causes warpage of the final molded product, and requires high dimensional stability. Suitable for use on rotor parts (fans).

Claims (8)

20 to 69% by weight of polypropylene, 1.0 to 30% by weight of modified polypropylene modified by unsaturated carboxylic acid or derivatives thereof, and 100 parts by weight of polypropylene resin composition consisting of 30 to 50% by weight of glass fiber and mica as inorganic filler A polypropylene resin composition comprising 0.01 to 2.0 parts by weight of an organosilane compound. The polypropylene resin composition according to claim 1, wherein the polypropylene is an isotactic propylene homopolymer having a melt index of 5 to 70 g / 10 minutes (230 ° C.). The polypropylene of claim 1, wherein the modified polypropylene is a polypropylene homopolymer, an ethylene / propylene copolymer, or a propylene / α-olefin nonconjugated diene compound copolymer modified with an unsaturated carboxylic acid or a derivative thereof. Propylene Resin Composition. The unsaturated carboxylic acid according to claim 3, wherein the unsaturated carboxylic acid is maleic anhydride, itaconic anhydride, ditraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoester, acrylamide, maleic acid monoamide, N-butyl A polypropylene resin composition characterized by being at least two selected from the group consisting of maleimide, sodium acrylate and sodium methacrylate. The polypropylene resin composition according to claim 3, wherein the amount of unsaturated carboxylic acid or derivative thereof added to the modified polypropylene is 0.1 to 10% by weight relative to the polypropylene. The polypropylene resin composition according to claim 1, wherein the organosilane compound is an aminosilane compound containing one or two amino groups. The polypropylene resin composition according to claim 1, wherein the mixing ratio of glass fiber and mica in the inorganic filler is glass fiber: mica = 1: 0.5 to 8. The polypropylene resin composition according to claim 1, wherein the glass fiber of the inorganic filler has an average particle diameter of 5 to 15 mu m, a length of 1 to 16 mm, and a mica having an average particle diameter of 10 to 500 mu m.