阅读说明：本技术 耐划伤性得到提高的聚丙烯树脂组合物及利用其制造的汽车成形部件 (Polypropylene resin composition having improved scratch resistance and automobile molded part produced from the same ) 是由 朴哲熙 姜秉旭 徐元建 于 2018-10-30 设计创作，主要内容包括：本发明提供通过包含聚丙烯树脂、热塑性弹性体、毛绒形态的无机填充物来赋予优秀的耐冲击性的同时通过低收缩及取向性控制来赋予尺寸稳定性耐划伤性得到提高的聚丙烯树脂组合物。(The invention provides a polypropylene resin composition which comprises a polypropylene resin, a thermoplastic elastomer and an inorganic filler in a plush shape, thereby providing excellent impact resistance and simultaneously providing dimensional stability and scratch resistance through low shrinkage and orientation control.)

1. A polypropylene resin composition having improved scratch resistance, characterized in that,

comprises a polypropylene resin, a thermoplastic elastomer, and an inorganic filler in the form of wool pile,

the inorganic filler in the pile form includes one selected from the group consisting of silica, alumina, calcium oxide, potassium oxide, magnesium oxide, sodium oxide, iron oxide, and a combination thereof.

2. The polypropylene resin composition with improved scratch resistance according to claim 1,

the above polypropylene resin contains 5 to 10 weight percent of ethylene,

the polypropylene resin has a molecular weight distribution index of 4 to 6, which is obtained by dividing the weight average molecular weight by the number average molecular weight.

3. The polypropylene resin composition with improved scratch resistance according to claim 1, wherein the thermoplastic elastomer is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the polypropylene resin.

4. The polypropylene resin composition having improved scratch resistance according to claim 1, wherein the thermoplastic elastomer comprises at least one selected from the group consisting of polyolefin-based rubbers and styrenic hydrogenated block copolymer rubbers.

5. The polypropylene resin composition with improved scratch resistance as claimed in claim 1, further comprising 0.1 to 3 parts by weight of a compatibilizer per 100 parts by weight of the polypropylene resin.

6. The polypropylene resin composition with improved scratch resistance according to claim 1, wherein the inorganic filler in a fluffy form is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the polypropylene resin.

7. The polypropylene resin composition with improved scratch resistance according to claim 1, wherein the inorganic fillers in the pile form have an average length of 200 nm or more and an average aspect ratio of 50 or more.

8. The polypropylene resin composition having improved scratch resistance according to claim 1, further comprising at least one selected from the group consisting of a plate-like inorganic filler and a needle-like inorganic filler.

9. An automobile molded part comprising the polypropylene resin composition having improved scratch resistance according to any one of claims 1 to 8.

Technical Field

The present invention relates to a polypropylene resin composition having improved scratch resistance and an automobile molded part produced from the same.

Background

The polypropylene composite resin has not only excellent moldability, impact resistance, chemical resistance and the like, but also the advantages of low specific gravity and low cost, and can be widely used for automobile parts requiring safety and functionality, for example, bumpers, instrument panels, door trims, interior trims and the like. In terms of physical properties, although conventional polypropylene resin compositions have excellent rigidity, scratch resistance, impact resistance and the like, it is difficult to apply them in an uncoated state to actual industrial fields in practice because appearance problems and scratch problems are generated on the surface of a molded product when the composition is not coated.

In order to reduce production costs, at present, automotive interior materials such as instrument panels, door trim panels, and interior materials are injection-molded and then produced into products by a spray-free process that does not require a coating process. Accordingly, the resin composition used for such automotive interior materials needs to satisfy both safety and sensory effects, and to adopt materials having improved impact strength, rigidity, scratch resistance, and antistatic properties.

Further, with the trend of weight reduction of vehicles, the thickness of parts is becoming thinner, and there is an urgent need to develop a polypropylene composite resin having dimensional stability while ensuring fluidity required for injection molding.

The automobile interior materials generally used are injection-molded by adding polyolefin rubbers and various inorganic fillers to polypropylene, but have hitherto been faced with the difficulty that the above-mentioned impact resistance and scratch resistance tend to be opposite, and when a material having excellent fluidity is used for easy injection molding, it is not advantageous to maintain excellent impact characteristics.

Therefore, as materials for automobile interiors, particularly as materials for instrument panels, there is a need to develop materials having appropriate impact resistance and excellent scratch resistance and moldability.

Disclosure of Invention

Problems to be solved by the invention

An embodiment of the present invention provides a polypropylene resin composition having improved scratch resistance.

Another embodiment of the present invention provides an automobile molded part comprising an injection-molded article of the polypropylene resin composition having improved scratch resistance.

Means for solving the problems

In one embodiment of the present invention, a polypropylene resin composition comprising a polypropylene resin, a thermoplastic elastomer, and an inorganic filler in a fluffy form and having improved scratch resistance is provided.

In another embodiment of the present invention, there is provided an automobile molded part comprising an injection-molded article of the polypropylene resin composition having improved scratch resistance.

Effects of the invention

The polypropylene resin composition having improved scratch resistance can have excellent scratch resistance, in addition to excellent impact resistance by including an inorganic filler in a plush form and dimensional stability by low shrinkage and orientation control.

Detailed Description

Hereinafter, examples of the present invention are described in detail. However, this is merely an example, and the present invention is not limited thereto, and the present invention should be defined in accordance with the scope of the claims to be described later.

The invention isIn an example, there is provided a polypropylene resin composition having improved scratch resistance, comprising a polypropylene resin, a thermoplastic elastomer, an inorganic filler in a fluffy form comprising one selected from the group consisting of silica, alumina, calcium oxide, potassium oxide, magnesium oxide, sodium oxide, iron oxide and combinations thereof, and further comprising a plate-shaped inorganic filler and/or a needle-shaped inorganic filler according to needAn inorganic filler.

The polypropylene resin composition having improved scratch resistance can have excellent scratch resistance, in addition to excellent impact resistance by including an inorganic filler in a plush form and dimensional stability by low shrinkage and orientation control.

Specifically, the inorganic filler in a pile form included in the polypropylene resin composition having improved scratch resistance may have excellent scratch resistance by including one selected from the group consisting of silica, alumina, calcium oxide, potassium oxide, magnesium oxide, sodium oxide, iron oxide, and a combination thereof, that is, a chemical combination thereof, to impart excellent impact resistance, and also impart dimensional stability by low shrinkage and orientation control.

In this case, the inorganic filler in a pile form may have excellent impact resistance by including the inorganic filler in a pile form having a length of about 200 nm or more and an average aspect ratio of about 50 or more, and may have excellent scratch resistance by providing dimensional stability by low shrinkage and orientation control. Specifically, when the length and aspect ratio of the inorganic filler in the pile form are less than the above ranges, mechanical physical properties such as impact resistance and rigidity cannot be imparted, and a low shrinkage and orientation control effect cannot be imparted, which may cause a problem in dimensional stability.

Specifically, the total content of the inorganic fillers in the pile form may be about 5 parts by weight to about 30 parts by weight with respect to 100 parts by weight of the polypropylene resin. The inorganic filler in the pile form is contained in an amount within the above range, so that excellent scratch resistance is imparted to the polypropylene resin, and impact resistance and dimensional stability can be imparted. More specifically, when the content is less than the above range, the shape of the molded article formed therefrom may be easily deformed during handling because of insufficient improvement in mechanical rigidity, and when the content is more than the above range, impact resistance may be lowered.

The inorganic filler in pile form may be in the form of a plate-like inorganic filler and/or a needle-like inorganic filler, as required.

The polypropylene resin composition having improved scratch resistance may include, as a base material, a polypropylene resin including a random copolymer (typically, an ethylene-propylene copolymer) obtained by polymerizing a comonomer (comonomer) selected from the group consisting of ethylene, butene, pentene, hexene, and octene in homo-polypropylene or propylene; a block copolymer obtained by copolymerizing a polyethylene-propylene rubber in polypropylene; branched polypropylene; and combinations thereof.

Specifically, the polypropylene resin may contain about 5 to about 10 weight percent of ethylene. The polypropylene resin composition having improved scratch resistance may be economically provided with excellent processability by reducing cost by including about 40 to about 90 weight percent of the polypropylene resin, and may be provided with excellent mechanical strength and excellent impact resistance by including the composition together with the inorganic filler in a plush form.

In this case, the polypropylene resin contains about 5 to about 10% by weight of ethylene, and as a specific example, it may be a highly crystalline ethylene-propylene copolymer resin having an Isotactic index (Isotactic index) of about 97 to about 99, which is related to the stereoregularity of the polymer, as measured by nuclear magnetic resonance carbon spectrum (13C NMR), and excellent rigidity and heat resistance may be imparted.

The polypropylene resin has the isotactic index and a melt index of about 5g/10min to about 50g/10min measured at 230 ℃ under a 2.16kg load, thereby having excellent mechanical rigidity and impact resistance and imparting excellent molding processability.

Also, the polypropylene resin has a molecular weight distribution Index (weight average molecular weight/number average molecular weight) of about 3 to about 7, specifically, about 4 to about 6, and has excellent mechanical physical properties and moldability, thereby imparting excellent processing effects. Therefore, the polypropylene resin composition containing the same and having improved scratch resistance is very useful for producing molded articles for automobile interior materials as injection molded articles thereof, particularly complex molded articles having a complex three-dimensional structure such as an area and a thickness, for example, a cushion pad.

The polypropylene resin composition having improved scratch resistance may include a thermoplastic elastomer, and the thermoplastic elastomer is not limited to those known in the art, and may be, for example, a polyolefin-based thermoplastic elastomer, a styrene-based hydrogenated block copolymer rubber, or the like. These may be used alone or in combination of two or more.

More specifically, the polyolefin-based thermoplastic elastomer may be an ethylene-propylene copolymer rubber, an ethylene-1-butene copolymer rubber, an ethylene- α -olefin copolymer rubber such as an ethylene-1-hexene copolymer rubber or an ethylene-1-octene copolymer rubber, or an ethylene- α -olefin nonconjugated diene copolymer rubber such as an ethylene-propylene-diene terpolymer rubber (EPDM).

The ethylene α -olefin copolymer rubber can be obtained by polymerizing a titanium compound such as a titanium halide with a Ziegler-type catalyst comprising an alkylaluminum-magnesium complex, an organoaluminum-magnesium complex such as an alkylalkoxyaluminum-magnesium complex, an alkylaluminum or an alkylaluminum chloride, etc. As a polymerization method, a gas phase flow method, a solution method, a slurry method, etc. can be used.

For example, the styrene-based hydrogenated block copolymer rubber may be a hydrogenated styrene-butadiene block copolymer (SEBS), a hydrogenated styrene isoprene copolymer (SEPS), or the like. These may be used alone or in combination of two or more.

The styrene hydrogenated block copolymer (SEBS, SEPS) can be prepared by common anion active polymerization method.

The hydrogenated styrene-butadiene block copolymer (SEBS) can be produced by a method of hydrogenating a triblock copolymer obtained by polymerizing styrene, butadiene and styrene in this order, or a method of hydrogenating a diblock copolymer of styrene-butadiene, which is then converted into a triblock copolymer by a compatibilizer. Also, in the above method, a hydrogenated styrene isoprene copolymer (SEPS) can be prepared using isoprene instead of butadiene.

As an example, the thermoplastic elastomer of the present invention has a melt index (melt flow rate, 230 ℃, 2.16kg load, ASTM D1238) of 0.5g/10 min to 150g/10 min, preferably 0.7g/10 min to 100g/10 min, and more preferably 0.7g/10 min to 80g/10 min. If the melt index is less than 0.5g/10 minutes, it may be difficult to ensure high fluidity. If the melt index is more than 150g/10 min, the molded article may have poor appearance.

The thermoplastic elastomer may be included in an amount of about 5 parts by weight to about 30 parts by weight, relative to 100 parts by weight of the polypropylene resin. The thermoplastic elastomer can enhance the impact strength, particularly, the surface impact strength by containing the above-mentioned range. Specifically, the impact strength may be reduced in the case of less than the above range, and the fluidity and compatibility may be restricted in the case of more than the above range.

The polypropylene resin composition having improved scratch resistance may further comprise one additive selected from the group consisting of a compatibilizer, a slip agent, an antioxidant, a neutralizer, a light stabilizer, and a combination thereof.

The compatibilizer is used to improve the compatibility between the inorganic fillers in pile form and the plate-shaped inorganic fillers, and between the needle-shaped inorganic fillers and the resin contained in the polypropylene resin composition having improved scratch resistance, and can optimize the dispersion degree by improving the compatibility, thereby imparting excellent mechanical rigidity and impact resistance and dimensional stability.

Specifically, the compatibilizer contains, as the modified polyolefin resin, a functional group that reacts with the inorganic filler in the main chain or the terminal of the polyolefin, and the functional group may be maleic acid, anhydrous maleic anhydride, carboxylic acid, hydroxyl, vinyl acetate, glycidyl methacrylate, vinyloxazoline, acrylic acid, or the like, for example.

Specifically, the modified polyolefin resin may include about 1 to about 3 weight percent of functional groups reactive with the inorganic filler in the side chain. More specifically, when the content of the functional group of the side chain is less than the above range, a phenomenon of lowering of physical properties due to lowering of compatibility may occur, and since the substitution amount of the functional group is small, the surface adhesion and dispersion efficiency with the inorganic filler contained in the polypropylene resin composition having the improved scratch resistance may be remarkably reduced. In contrast, when it is more than the above range, since the modified polypropylene contained in the resin composition of polypropylene is easily deteriorated in its own characteristics and the physical property-increasing effect is lowered, and the preparation cost is high as compared with the intended effect, the practicality is remarkably lowered.

The compatibilizer is included in an amount of about 0.1 to 3 parts by weight with respect to 100 parts by weight of the polypropylene resin, and can optimize dispersion by improving compatibility between the inorganic filler and the resin, thereby imparting excellent mechanical rigidity and impact resistance, and simultaneously imparting dimensional stability.

The slip agent is used for improving the lubricity of the polypropylene resin composition having improved scratch resistance at the time of molding, and may be one selected from the group consisting of a silicone-based slip agent, an amide-based slip agent, and a combination thereof.

The antioxidant may be one selected from the group consisting of phenolic antioxidants, phosphite antioxidants, thiopropionate (Thiodipropionate), and combinations thereof.

The polypropylene resin composition having improved scratch resistance may be used, for example, calcium stearate or zinc oxide as a neutralizer, or Hindered (Hindered) amines as a light stabilizer.

In another embodiment of the present invention, there is provided a molded article for an automobile interior material, which comprises an injection-molded article of the polypropylene resin composition having improved scratch resistance. Specifically, the polypropylene resin composition with improved scratch resistance comprises a polypropylene resin, a thermoplastic elastomer and an inorganic filler in a fluffy form, wherein the inorganic filler in the fluffy form comprises one selected from the group consisting of silica, alumina, calcium oxide, potassium oxide, magnesium oxide, sodium oxide, iron oxide and a combination thereof, namely a chemical combination thereof, and the molded article for an automobile interior material comprises an injection molded article of the polypropylene resin composition with improved scratch resistance. This provides excellent impact resistance, and also provides dimensional stability by low shrinkage and orientation control, thereby providing excellent scratch resistance.

In general, injection moldings of polypropylene resin compositions have a reduced impact resistance or rigidity as the scratch resistance is improved. On the contrary, the injection-molded article of the polypropylene resin composition having improved scratch resistance described above not only has excellent scratch resistance, but also satisfies high levels of impact resistance and rigidity.

Specifically, the polypropylene resin composition injection-molded product having improved scratch resistance may have excellent scratch resistance, and may have a scratch resistance having an △L value of 0.5 or less by the West scratch test method.

Further, the injection-molded article of the polypropylene resin composition having the improved scratch resistance can have excellent impact strength not only at normal temperature but also at low temperature. Specifically, it has an impact strength of about 45.0Kgfcm/cm at normal temperature, and an impact strength of about 5.0Kgfcm/cm or more at low temperature (about-10 ℃), thereby preventing the generation of cracks even in winter. The injection-molded article of the polypropylene resin composition having improved scratch resistance has excellent impact strength and about 12500kgf/cm²The above rigidity makes it possible to use the resin composition as a material for automobile parts.

And, due to the scratch resistanceThe injection molded article of the polypropylene resin composition having improved scratch may have about 210kgf/cm²The above tensile strength and the shrinkage rate of about 150% or more, and the heat distortion temperature of about 125 ℃ or more, and therefore, the composition is suitable for molded articles for automobile interior materials.

The polypropylene resin composition having improved scratch resistance has high fluidity and excellent mechanical rigidity, and can impart impact resistance and excellent dimensional stability, and a molded article for an automobile interior material comprising the injection-molded article has excellent moldability and excellent mechanical physical properties, and can ensure excellent scratch resistance. As a specific example, the automobile interior material may be an interior trim, an interior door trim, a storage box, an instrument panel, a cushion pad, or the like.

Specifically, the molded article for an automobile interior material is very suitable for automobile parts requiring high levels of rigidity, impact resistance, heat resistance, dimensional stability, and scratch resistance because of its complicated three-dimensional structure such as area, thickness, and the like, for example, a cushion pad.

In the following, although specific embodiments of the invention are disclosed. However, the following examples are merely illustrative or illustrative of the present invention and do not limit the present invention.