KR20150129533A - Polypropylene composition with excellent impact resistance and scratch resistance - Google Patents

Abstract

The present invention provides a polypropylene resin composition which comprises: (A) 10 to 70 wt% of a crystalline ethylene-propylene copolymer; (B) 5 to 30 wt% of an ethylene-α-olefin copolymer; (C) 5 to 30 wt% of polypropylene elastomer; (D) 5 to 40 wt% of an inorganic filler including talc and precipitated calcium carbonate, and selectively including heavy calcium carbonate; and (E) 1 to 10 wt% of modified polypropylene. According to the present invention, the composition can widely apply price competitiveness of an original price to a car built-in component, a household electrical appliance, etc. as having an excellent property such as high strength, impact resistance, scratch resistance, etc., being rarely transformed, and being capable of replacing an expensive whisker.

Description

TECHNICAL FIELD [0001] The present invention relates to a polypropylene resin composition having excellent impact resistance and scratch resistance,

The present invention relates to a polypropylene resin composition having excellent impact resistance and scratch resistance, and more particularly, to a polypropylene resin composition having excellent impact resistance and scratch resistance, and more particularly, And can be widely applied to automobile interior parts and home appliances having cost competitiveness because it can replace whiskers which are excellent in physical properties such as high rigidity, impact resistance and scratch resistance and are less expensive, To a polypropylene resin composition.

Particularly, filler and door trim are compounded with polypropylene including rubber-like ethylene-propylene rubber, ethylene-butene rubber, ethylene-octene rubber, to be.

Particularly, the material used for the filler or the door trim is required to have excellent scratch resistance, excellent impact strength at room temperature and low temperature, high heat resistance, high rigidity, and no post-distortion. Therefore, in order to satisfy the room temperature and low temperature impact strength, a rubber phase having a high content has to be added, and a filler having a certain amount or more has been used in order to secure high rigidity.

However, such use is not in line with the development direction of automobile materials which is progressing to be thinner and lightweight with the aim of environment friendliness, and the addition of a large amount of rubber and inorganic filler to polypropylene causes degradation of rigidity, increase of specific gravity, It is difficult to apply it to an automobile interior part because it has problems of reduction and moldability.

On the other hand, precipitated calcium carbonate has a high aspect ratio unlike the plate-like talc used as a conventional inorganic filler, and has excellent mechanical strength and scratch resistance. However, it is vulnerable to lack of impact strength and post- It is not easy to apply to automotive interior materials. Accordingly, techniques for blending polypropylene with whisker or nano-clay, which are bases of magnesium hydroxide, have been continuously developed.

However, whiskers and nanoclays have excellent physical properties such as high rigidity and low specific gravity

In spite of meeting the environment-friendly tendency to reduce carbon emissions through thinning and light weighting, it is possible that the polypropylene compounding may cause physical property deviation and post-deformation problems due to lack of dispersion power, and due to cost burden, It is difficult to expand the scope of application.

Korean Patent Laid-Open No. 1998-0087442 discloses a resin composition comprising a polypropylene and a hydrogenated block copolymer and an inorganic filler. The filler is a natural silicate, synthetic silicate, carbonate, hydroxide, It has been proposed to add two or more kinds of fillers in the form of a flake, a fibrous filler or a balloon filler to obtain a molded article excellent in heat resistance, rigidity and impact resistance and having an excellent appearance, but such a resin composition is excellent in scratch resistance It was not satisfactory for application to automobile interior parts.

Korean Patent Laid-Open Publication No. 2013-0070428 proposes that a resin composition composed of a filler such as polypropylene, a rubber component, a master batch-formed nano clay, and whisker can obtain a molded article excellent in low specific gravity, scratch resistance and appearance characteristics , There are limitations such as a decrease in impact strength due to the residue of peroxide used in the process of manufacturing a masterbatched nano-clay, and a rise in cost due to the use of whiskers after the deformation due to a decrease in the dispersing power of the nano-clay itself.

Therefore, there is a need for a polypropylene resin composition excellent in physical properties such as high rigidity, impact resistance and scratch resistance, and less deformed, while using an inorganic filler capable of replacing whisker which is an expensive inorganic filler.

1: Korea Patent Publication No. 1998-0087442, December 5, 1998 1: Korea Patent Publication No. 2013-0070428, June 27, 2013

Therefore, the present inventors have found that, instead of using an expensive filler, it is possible to reduce the production cost and the cost of replacing imported materials by localization of materials, When an inorganic filler, optionally containing heavy calcium carbonate, is added to the talc and precipitated calcium carbonate in a predetermined amount of the polypropylene resin composition while devising the material to be represented, the material is suitable for use as an automobile interior part, It was found that the resin composition according to the present invention was completed.

Accordingly, an object of the present invention is to provide a polypropylene resin composition for automobile interior parts, which is excellent in physical properties such as high rigidity, high impact resistance and scratch resistance, has less post distortion, and does not use expensive whiskers, .

In order to solve the above problems, the present invention provides a thermoplastic resin composition comprising (A) 10 to 70% by weight of a crystalline ethylene-propylene copolymer; (B) 5 to 30% by weight of an ethylene -? - olefin copolymer; (C) 5 to 30% by weight of a polypropylene elastomer; (D) 5 to 40% by weight of an inorganic filler comprising talc and precipitated calcium carbonate, optionally containing heavy calcium carbonate; And (E) 1 to 10% by weight of a modified polypropylene.

The polypropylene composite resin composition according to the present invention has excellent properties such as high rigidity, high impact resistance, scratch resistance, and low post-warping characteristics. In addition, because it can replace expensive whiskers, it can replace high-priced engineering plastics based on cost competitiveness, so it can be used for exterior parts and home appliances as well as interior parts for automobiles.

Hereinafter, the present invention will be described in detail.

(A) 10 to 70% by weight of a crystalline ethylene-propylene copolymer; (B) 5 to 30% by weight of an ethylene -? - olefin copolymer; (C) 5 to 30% by weight of a polypropylene elastomer; (D) 5 to 40% by weight of an inorganic filler comprising talc and precipitated calcium carbonate, optionally containing heavy calcium carbonate; And (E) 1 to 10% by weight of a modified polypropylene.

The crystalline ethylene-propylene copolymer (A) is an ethylene monomer content of 1 to 10% by weight, preferably 3 to 8 wt%, and the air isotactic index (isotactic index of the polypropylene of the copolymer, ¹³ C-NMR measurements Preferably 96 to 99%, and a weight average molecular weight of 100,000 to 400,000 g / mol, a melt flow index of 0.5 to 100 g / _{10 min} at a temperature of 2.16 kg and 230 DEG C _, Use 5 ~ 40 g / _{10 min} .

If the isotactic index (measured by ¹³ C-NMR) of the propylene is less than 96%, the stiffness and surface hardness of the molded article are unsatisfactory. If the propylene content exceeds 99%, the impact strength may be deteriorated. If the flow index is less than 0.5 g / _{10 min,} flowability and moldability are deteriorated. If the flow index is more than 100 g / _{10 min} , flash generation increases during injection molding.

The crystalline ethylene-propylene copolymer (A) is used in an amount of 10 to 70% by weight, preferably 45 to 65% by weight based on the total weight of the resin composition. If the amount of the crystalline ethylene-propylene copolymer is less than 10% by weight, moldability and shrinkage increase may occur. If the crystalline ethylene-propylene copolymer content exceeds 70% by weight, impact strength may be lowered. good.

Wherein the ethylene /? - olefin copolymer (B) has a melt index of 0.5 to 6.0 g / 10 min (230 占 폚, 2.16 kg) as a rubber component copolymerized under a metallocene catalyst, Ethylene-α-olefin copolymer (B-2) having an ethylene-propylene copolymer rubber (B-1) having a Mooney viscosity of 5 to 60 ML1 + 4 (121 ° C.) it is preferable to use an? -olefin copolymer.

Specifically, the ethylene-propylene copolymer rubber (B-1) has a propylene content of 20 to 50 wt% and a melt index of 0.5 to 6.0 g / _{10 min} (230 DEG C, 2.16 kg) ML1 + 4 (121 占 폚), and more preferably 15 to 50 ML1 + 4 (121 占 폚). If the ethylene-propylene copolymer rubber has a pattern viscosity of less than 5 ML1 + 4 (121 DEG C), the mechanical strength and dimensional stability decrease. When the ethylene-propylene copolymer rubber has a flow viscosity of more than 70 ML1 + 4 (121 DEG C) It is preferable to use the one within the above range because a sexual problem may occur.

Next, it is preferable that the ethylene /? - olefin copolymer (B-2) to be blended has a Mooney viscosity of 5 to 60 ML1 + 4 (121 占 폚) , The impact resistance is decreased. If it exceeds 60 ML1 + 4 (121 DEG C), the appearance of defective appearance and moldability may occur due to the deterioration of the fluidity.

When the glass transition temperature is higher than -50 ° C., the low-temperature impact resistance is lowered. When the glass transition temperature is lower than -65 ° C., the rigidity and the heat resistance are lowered. Therefore, It is recommended to use the product within the range.

When the above two types of rubbers (ethylene-propylene rubber and ethylene-? -Olefin copolymer) are used alone, there arises a problem of rigidity or impact resistance. Therefore, considering the balance of rigidity, impact resistance and molding shrinkage ratio, .

Therefore, the ethylene /? - olefin copolymer (B) in the present invention has a melt flow rate within the range of 40 to 70% by weight of the ethylene-propylene rubber (B-1) and 30 to 60% by weight of the ethylene /? - olefin copolymer More preferably 50 to 65% by weight of the ethylene-propylene rubber (B-1) and 35 to 50% by weight of the ethylene-? -Olefin copolymer (B-2) .

The ethylene /? - olefin copolymer (B) is used in an amount of 5 to 30% by weight, more preferably 10 to 20% by weight based on the total weight of the resin composition. If it is less than 5% by weight, %, The strength and heat resistance deteriorate. Therefore, it is preferable to use it within the above range.

Next, the polypropylene elastomer (C) is prepared by directly reacting ethylene-propylene rubber and ethylene-butylene rubber with homopolypropylene up to 20 to 85% by weight in three gas phase reactors to produce a rubber component in a polypropylene matrix In order to exhibit low shrinkage and low linear expansion characteristics, a polypropylene elastomer (55% to 75% by weight) of C2C4 bipolymer copolymer rubber component And a polypropylene elastomer (C-2) containing 50 to 70% by weight of a C2C3 bipolymer copolymer rubber component are preferably used in combination.

If the content of the C2C4 copolymer rubber component of the polypropylene elastomer (C-1) is less than 55% by weight, the impact resistance and the shrinkage rate are lowered. If the content is more than 75% by weight, When the content of the C2C3 copolymer rubber component of the polypropylene elastomer (C-2) is less than 50% by weight, the impact resistance and the linear expansion coefficient are decreased. When the content is more than 70% by weight, stiffness and flow marks are generated. .

Therefore, it is more preferable that 50 to 90% by weight of the polypropylene elastomer (C-1) and 10 to 50% by weight of the polypropylene elastomer (C-2) are used in order to maintain a low linear expansion coefficient and balance of physical properties good.

The polypropylene elastomer (C) is used in an amount of 5 to 30% by weight, more preferably 10 to 20% by weight based on the total weight of the resin composition. When the content of the polypropylene elastomer (C) is less than 5% by weight, there is a problem that the dimensional stability is decreased. When the content is more than 30% by weight, mechanical properties are deteriorated.

The inorganic filler (D) is preferably 5 to 40% by weight of an inorganic filler comprising talc and precipitated calcium carbonate, optionally containing heavy calcium carbonate.

In general, it is added to reinforce rigidity. As a base of the present invention, based on precipitated calcium carbonate and talc, kaolinite, calcined cray, olastonite, heavy calcium carbonate, magnesium carbonate, mica, basic magnesium sulfate whisker, Calcium phosphate whiskers, calcium whiskers, aluminum borate whiskers, glass fibers, and glass bubbles. More preferably, heavy calcium carbonate is used. This is because the high aspect ratio spherical heavy calcium carbonate characteristic can solve the problem of being susceptible to the deformation of the high aspect ratio precipitated calcium carbonate.

The amount of calcium carbonate (D-1): talc (D-2): heavy calcium carbonate (D-3) = 1: 2 was used for simultaneous use of precipitated calcium carbonate, talc and heavy calcium carbonate. : 0.5 to 1: 5: 1 by weight. More preferably 1: 2: 0.5 to 1: 3.5: 1. When the heavy calcium carbonate is used in a weight ratio of 1: 2: 0.5, the effect of improving the impact strength is insignificant. When the heavy calcium carbonate is used in a ratio of 1: 2: 0.5, There is a problem that the mechanical strength is decreased when it is used in excess, so it is preferable to use it within the above range.

In addition, the precipitated calcium carbonate preferably has an average particle size of 4 to 6 μm and an average aspect ratio of 5 to 20. When the average particle size is less than 4 탆, there is a problem that dispersion is not easy. When the average particle size is more than 6 탆, the impact strength is decreased. When the aspect ratio is less than 5, It is preferable to use precipitated calcium carbonate within the above range because the probability of occurrence of post-warpage increases and the probability of occurrence of physical property decrease due to fracture during extrusion and injection may increase.

The heavy calcium carbonate is preferably one having an average particle size of 0.5 to 10 탆. When the particle size is less than 0.5 탆, dispersion is not easy. When the particle size is more than 10 탆, mechanical properties are decreased It is better to use one within the above range.

The inorganic filler (D) is preferably used in an amount of 5 to 40% by weight based on the total weight of the resin composition. If the inorganic filler (D) is less than 5% by weight, the rigidity and heat resistance are lowered. It is preferable to use it within the above range.

The modified polypropylene (E) used in the present invention can be obtained by copolymerizing a polypropylene homopolymer or a polypropylene copolymer with a monomer selected from the group consisting of maleic anhydride, maleic acid, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, cinnamic acid and citraconic acid Selected unsaturated carboxylic acid or acid anhydride is grafted together with the wax.

When the graft ratio is less than 0.5 weight%, the compatibility between the resins is deteriorated. When the graft ratio is more than 10 weight%, the physical properties are lowered. In the above-mentioned range. The modified polypropylene has a weight average molecular weight of 100 to 5,000 g / mol, preferably a weight average molecular weight of 300 to 3,000 g / mol. If the modified polypropylene has a weight average molecular weight of less than 100 or more than 5,000, do.

The modified polypropylene (E) is used in an amount of 1 to 10% by weight, more preferably 2 to 5% by weight based on the total weight of the resin composition. If the modified polypropylene is less than 1% by weight, the compatibilizer If the content is more than 10% by weight, there are disadvantages in terms of lowering of physical properties and economical efficiency.

These modified polypropylenes improve the compatibility of polypropylene with rubber and talc to prevent degradation of mechanical properties as compared with the case of using inorganic filler such as precipitated calcium carbonate which is hydrophobic, Which helps to further improve the scratch performance, which is distributed and advantageous in the use of precipitated calcium carbonate.

The polypropylene resin composition of the present invention may further contain additives such as primary and secondary antioxidants, ultraviolet absorbers, light stabilizers, pigments, dispersants, nucleating agents, processing lubricants and couplings At least one additive selected from the group consisting of

In order to prepare the resin composition, the components may be homogeneously mixed in a super mixer and then manufactured in a melt kneader such as a uniaxial and twin screw extruder, a Banbury mixer, or a kneader. In the present invention, a twin-screw extruder may be used, and the mixture is preferably stirred at a temperature of 180 to 220 ° C under a rotation speed of 100 to 300 RPM.

The resin composition of the present invention thus produced has excellent physical properties such as high rigidity, high impact resistance and scratch resistance, is less deformed, can replace costly whiskers, and has cost competitiveness at a cost.

Therefore, the present invention can be widely used for automobile interior parts such as pillars, door trim, etc., and can be widely used for home appliances such as vacuum cleaners.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example  1 to 6

Using the raw materials shown in Tables 1 to 5 below, a polypropylene composite resin composition was prepared according to the composition ratios shown in Table 6 below, and the resin composition was injection-molded at an injection temperature of 220 DEG C and a mold temperature of 50 DEG C Molded to prepare test pieces of Examples 1 to 6.

Component (A): Crystalline ethylene-propylene copolymer division A-1 A-2 The melt flow index (g / 10 min) 10 30 Weight average molecular weight (g / mol) 330,000 150,000 Ethylene content (% by weight) 4.8 4.7

Component (B): Ethylene -? - olefin copolymer division B-1 B-2 Pattern viscosity (ML1 + 4 at 121 ° C) 70 25 Comonomer content (% by weight) 31 (propylene) 44 (octene)

Component (C): Polypropylene elastomer division C-1 C-2 The melt flow index (g / 10 min) 8 4 Comonomer content (% by weight) 70 55 Comonomer type C2C4 rubber C2C3 rubber

(Polypropylene elastomer: Catalloy Process product from Basell)

Component (D): Inorganic filler division D-1 D-2 D-3 Average diameter (占 퐉) 5.1 5.5 6.0 Aspect Ratio 12 4 One

(D-1: precipitated calcium carbonate, D-2: talc, D-3: heavy calcium carbonate)

Component (E): Modified polypropylene division E Graft rate (% by weight) 7 Weight average molecular weight (g / mol) 1,000

Comparative Example  1 to 8

Using the raw materials shown in Tables 1 to 5 above, test pieces of Comparative Examples 1 to 8 were prepared in the same manner as in Examples 1 to 6, according to the composition ratios shown in Table 6 below.

The properties of the test pieces prepared according to Examples 1 to 6 and Comparative Examples 1 to 8 were measured in the following manner, and the composition and physical properties of the polypropylene resin composition are shown in Table 6 below.

Composition and physical property value of polypropylene resin composition Furtherance
(weight%) Example Comparative example One 2 3 4 5 6 One 2 3 4 5 6 7 8 phrase
castle
castle
minute A-1
A-2 30
14 47
- 35
10 17
29 20
25 -
45 26
14 26
- 21
19 30
12 25
32.5 17
34 22
21 10
34 B-1
B-2 7
4 4
7 5
7 8
3 6
6 7
5 -
14 5
5 25
- 6
7 -
12 6
11 6
6 5
10 C-1
C-2 10
2 7
6 10
3 3
10 5
8 7
7 11
16 6
6 6
5 7
5 8
5 14
- 7
6 6
5 D-1
D-2
D-3 5
25
- 7
19
- 5
21.5
- 6
19
- 5
16
4 7
17
3 7
8
- 5
44
- 6
13
- 6
16
- 14
-
- 6
12
- 2
16
12 11
16
One E 3 3 3.5 5 5 2 4 3 5 11 3.5 - 2 2 Total quantity 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Experiment Item goal Actual measurement Flexural modulus
(kgf / cm2) 21000
More than 22300 23300 21600 23600 22400 22600 17100 27600 20200 19700 18100 16200 16800 21600 Phase IZOD shock
(kgf · cm / cm) 12.0 or higher 12.3 14.1 12.2 15.6 17.1 17.2 18.3 3.2 9.4 8.1 11.7 8.8 18.5 9.9 Heat deformation temperature (캜) 125 or more 131 129 130 132 127 129 107 141 124 124 104 118 108 117 Scratch resistance (grade) 3.5 or higher 3.5 4.5 4 4 3.5 4.5 3 2 4 3 4.5 3.5 3 4

Experimental Example : Measurement of Physical Properties of Specimen

The properties of the test pieces prepared according to Examples 1 to 6 and Comparative Examples 1 to 8 were measured in the following manner, and the results are shown in Table 6 above.

The physical properties shown in Table 6 are the average values except for the upper limit value and the lower limit value of seven specimens measured, and the test method thereof is as follows.

(1) Flexural modulus: Measured according to ASTM D 790. The specimen thickness was 6.2 mm, the measurement speed was 10 mm / min, and the unit of measurement was kgf / cm ² .

(2) Izod Impact Strength: Measured according to ASTM D256. The specimen thickness was 6.3 mm, and the notch was measured using a notch. The measurement unit was kgf · cm / cm.

(3) Heat distortion temperature: Measured according to ASTM D648. The specimen thickness was 6.2 mm, measured under a stress of 4.6 kgf, and the unit of measurement was ℃.

(4) Scratch resistance: Measured according to JIS K3718. The surface of the test piece manufactured using the scratch measuring machine was scratched under the conditions shown in Table 7, and the surface state was evaluated according to the following Table 8.

Scratch resistance measurement conditions Item Condition Load (N {kgf}) 4.9 {0.5} STROKE (mm) 100 ± 5 Friction speed (mm / sec) 100 Scratcher

Number of scratches 1 time

Scratch resistance criteria Rating Criteria Scratch width (탆) Exterior 5 <20 Almost no surface damage 4 100 to 200 No obvious surface damage is recognized 3 200-300 Fine surface damage is recognized 2 300 to 400 Whitening due to obvious surface damage One > 400 Very severe surface damage

As shown in Table 6 above, the polypropylene resin compositions of Examples 1 to 6 according to the present invention were found to be suitable for use between the components, especially inorganic fillers with precipitated calcium carbonate: talc: heavy calcium carbonate = 1: 2: 0.5 To 1: 5: 1 weight ratio, it was confirmed that the physical properties such as rigidity, impact resistance and scratch resistance were superior to those of Comparative Examples 1 to 8, which were outside the scope of the present invention.

The present invention has excellent physical properties such as high rigidity, high impact resistance and scratch resistance, less deformation, and does not use expensive whiskers, so that it can be cost competitive with cost, and can be used for automobile interior parts such as pillars and door trim Can be widely used, and can be widely used in home appliances such as vacuum cleaners.

Claims (9)

(A) 10 to 70% by weight of a crystalline ethylene-propylene copolymer;
(B) 5 to 30% by weight of an ethylene -? - olefin copolymer;
(C) 5 to 30% by weight of a polypropylene elastomer;
(D) 5 to 40% by weight of an inorganic filler comprising talc and precipitated calcium carbonate, optionally containing heavy calcium carbonate; And
(E) 1 to 10% by weight of a modified polypropylene;
And a polypropylene resin composition.
The method of claim 1, wherein the crystalline ethylene-propylene copolymer (A) is 1-10% by weight of ethylene monomer content, a weight average molecular weight of 100,000 ~ 400,000 g / mol, an isotactic index (isotactic index, ¹³ of propylene C-NMR) of 96% or more and a melt flow index of 0.5 to 100 g / _{10 min} (230 占 폚, 2.16 kg).
The ethylene /? - olefin copolymer (B) according to claim 1, wherein the ethylene /? - olefin copolymer (B) has a melt index of 0.5 to 6.0 g / 10 min (230 占 폚, 2.16 kg) Olefin copolymer (B-1) having an ethylene-propylene copolymer rubber (B-1) and an ethylene-? -Olefin copolymer (B-2) having a pattern viscosity of 5 to 60 ML1 + 4 &Lt; / RTI &gt;
The polypropylene elastomer (C) according to claim 1, wherein the polypropylene elastomer (C) comprises a polypropylene elastomer (C-1) and a C2C3 bipolymer copolymer rubber component (50) containing 55 to 75% by weight of a C2C4 bipolymer copolymer rubber component And at least one polypropylene elastomer selected from the group consisting of polypropylene elastomer (C-1) and polypropylene elastomer (C-2) containing at least 70% by weight of a polypropylene elastomer.
The polypropylene resin composition according to claim 1, wherein the precipitated calcium carbonate has an average particle size of 4 to 6 탆 and an aspect ratio of 5 to 20.
The polypropylene resin composition according to claim 1, wherein the heavy calcium carbonate has an average particle size of 0.5 to 10 mu m.
The polypropylene resin composition according to claim 1, wherein the inorganic filler (D) has a mixing ratio of talc: precipitated calcium carbonate: heavy calcium carbonate of 1: 2: 0.5 to 1: 5: 1.
The polypropylene resin composition according to claim 1, wherein the modified polypropylene (E) is obtained by grafting 0.5 to 10% by weight of an unsaturated carboxylic acid or an acid anhydride together with the wax to a polypropylene monolith or a polypropylene copolymer Composition.
The polypropylene resin composition according to any one of claims 1 to 8, wherein the polypropylene resin composition comprises at least one additive selected from the group consisting of an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a dispersant, a nucleating agent, Further comprising a polypropylene resin composition.