KR101330893B1 - Polypropylene resin composition - Google Patents

Abstract

The present invention relates to a polypropylene resin composition, the polypropylene resin composition of the present invention comprises a propylene resin comprising 65 to 95% by weight of the crystalline propylene polymer and 5 to 35% by weight of the α-olefin copolymer; And 0.01 to 2.0% by weight of the organic peroxide relative to the propylene resin. Polypropylene resin composition according to the present invention is improved impact resistance, rigidity and whitening resistance can be effectively applied to home appliances and automotive interior and exterior parts.

Description

Polypropylene resin composition {POLYPROPYLENE RESIN COMPOSITION}

The present invention relates to a polypropylene resin composition, and more particularly to a polypropylene resin composition excellent in impact resistance, rigidity and whitening resistance.

Generally, polypropylene resin compositions are widely used as materials for injection molded products because of their light weight and excellent mechanical properties for cost. In recent years, the use of polypropylene products has been expanded from simple exterior finishes or packaging materials to various fields requiring durability according to the user's usage environment. In particular, as products using polypropylene have become larger, products have become thinner for weight reduction. However, due to such thinning, there is a problem that it is easily broken by an external impact, and in order to improve it, a polypropylene product having a higher level of impact resistance with higher rigidity is required. However, in developing a material using polypropylene, impact resistance and rigidity tend to be inversely proportional, and also, there is a problem in that the whitening property is lowered by bending in terms of molecular structure. Therefore, there is a demand for the development of a material having excellent impact strength, rigidity, and whitening resistance, which can simultaneously satisfy the safety and aesthetic effects required when used as a material for automobile interior and exterior finishing materials or packaging materials.

For example, there is a method of adding an impact modifier to a polypropylene homopolymer to improve impact resistance. Introducing such an impact modifier has a sharp decrease in rigidity as the content of the modifier is increased, and in particular, the manufacturing cost increases due to the expensive rubber-elastic material. In addition, as a method for improving the whitening phenomenon, a method of adding styrene-ethylene butylene-styrene (SEBS) rubber to a polypropylene homopolymer has been proposed. However, the price of the SEBS is expensive, the amount of addition of the SEBS has a disadvantage in that the rigidity is lowered and the heat resistance is lowered.

The present invention is to solve the above problems of the prior art, an object of the present invention to provide a polypropylene resin composition excellent in impact resistance, rigidity and whitening resistance.

Aspects of the present invention for achieving the above object,

Propylene-based resins comprising 65 to 95% by weight of crystalline propylene polymer and 5 to 35% by weight of α-olefin copolymer; And

It is related with the polypropylene resin composition containing 0.01-2.0 weight% of organic peroxide with respect to the said propylene resin.

The crystalline propylene polymer may have a melt index of 0.1 to 500 g / 10 min (ASTM D1238).

The α-olefin copolymer may be a copolymer of an α-olefin monomer having 2 to 20 carbon atoms. In addition, the α-olefin copolymer may be a propylene-α-olefin copolymer or an ethylene-α-olefin copolymer. In addition, the α-olefin copolymer may have a density of 0.90 to 0.93 g / cm ³ .

The organic peroxide is diethyl peroxy dicarbonate, dipropyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, dibutyl peroxy dicarbonate, ethylhexyl peroxy dicarbonate, dioctyl peroxy dicarbonate, di (4-t-butylcyclohexyl ) May be one or more selected from the group consisting of peroxydicarbonate, dimyrisil peroxydicarbonate, and dicetyl peroxydicarbonate.

The polypropylene resin composition of the present invention not only has excellent impact strength and rigidity but also excellent whitening resistance. In addition, the polypropylene resin composition of the present invention is excellent in impact strength and whitening resistance can be effectively applied to home appliances, automotive interior and exterior parts and thin film molded products that require the safety and aesthetic effect of the material at the same time.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily practice.

The polypropylene resin composition of this invention contains a propylene resin.

The propylene resin is a base resin of the resin composition, and includes a crystalline propylene polymer and an α-olefin copolymer. The propylene-based resin can improve the rigidity and impact strength of the resin composition, and improve the injection moldability.

The propylene resin may be a mixed phase resin of the crystalline propylene polymer and an α-olefin copolymer or a resin prepared by kneading and melt processing them. The propylene-based resin may be prepared according to a conventional method for producing a resin, and is not particularly limited in the present invention.

The crystalline propylene polymer may be included in 65 to 95% by weight relative to the propylene resin. When included in less than 65% by weight, not only the rigidity but also heat resistance and surface hardness may significantly decrease or whitening may occur, and when included in excess of 95% by weight, the impact characteristics of the resin composition may be lowered.

The crystalline propylene polymer may have a melt index of 0.1 to 500 g / 10 min at 230 ° C. and 2.16 kg load under conditions according to ASTM D1238, preferably 1 to 100 g / 10 min, most Preferably 3 to 50 g / 10 min. When the melt index is less than 0.1 g / 10min, the porosity of injection molding is lowered, and when the melt index is more than 500 g / 10min, the impact strength of the resin composition may be significantly lowered.

The crystalline propylene polymer may be a homopolymer or binary copolymer comprising a propylene monomer, but preferably may be a propylene homopolymer.

The α-olefin copolymer may be included in an amount of 5 to 35 wt% based on the propylene resin. When included in less than 5% by weight may reduce the impact strength, when included in excess of 35% by weight may be reduced in rigidity and whitening may occur.

The α-olefin copolymer may have a density measured at room temperature (25 ° C.) of 0.90 to 0.93 g / cm ³ , and if the density is less than 0.90 g / cm ³ , the α-olefin copolymer may have a high resistance due to a difference in shrinkage rate with the crystalline propylene polymer. The whitening characteristics may be lowered, and when it exceeds 0.93 g / cm ³ , the impact strength characteristics of the composition may not be improved.

The α-olefin copolymer may include at least one of copolymers composed of C ₂ to C ₂₀ α-olefin monomers. For example, the α-olefin monomer may be ethylene, 1-butene, 1-pentene, 1-hexene, methyl-1-butene, methyl-1-pentene, 1-octene, 1-decene and the like. More specifically, the α-olefin copolymer may be an ethylene-α-olefin copolymer (except 2 carbon atoms) or a propylene-α-olefin copolymer (except 3 carbon atoms), preferably ethylene-butene, ethylene-hexene , Ethylene-octene, propylene-ethylene, propylene-butene, propylene-octene copolymers and the like, but is not limited thereto.

In addition, the content of the α-olefin monomer in the ethylene-α-olefin copolymer or propylene-α-olefin copolymer may be 1 to 30% by weight. If the content of the α-olefin monomer is less than 1% by weight, there is a problem that the impact strength is lowered, and if the content of more than 30% by weight, the problem of increasing whitening may occur.

The α-olefin-based copolymer is not limited in the form of the copolymer, it may be a random copolymer, alternating copolymer or block copolymer.

The polypropylene resin composition of the present invention contains an organic peroxide.

The organic peroxide may improve impact strength while maintaining the flexural modulus by reforming the propylene-based resin.

The organic peroxide may be included in an amount of 0.01 to 2.0 wt% with respect to the propylene-based resin, preferably, 0.05 to 0.5 wt%. If the content is less than 0.01% by weight, the impact properties may be improved. If the content is more than 2.0% by weight, the gel content increases, resulting in deterioration in appearance, and the improvement of the properties on impact strength. May not appear.

The organic peroxide is diethyl peroxy dicarbonate, dipropyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, dibutyl peroxy dicarbonate, ethylhexyl peroxy dicarbonate, dioctyl peroxy dicarbonate, di (4-t-butylcyclohexyl ) May be one or more selected from the group consisting of peroxydicarbonate, dimyrisil peroxydicarbonate and dicetyl peroxydicarbonate, preferably di (4-t-butylcyclohexyl) peroxydicarbonate and / or disetyl perox It may be a dicarbonate.

The polypropylene resin composition according to the present invention may further include additives known in the art within the scope of not impairing the object of the present invention. Specifically, for example, antioxidants, nucleating agents, heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents, flame retardants, pigments, dyes and the like can be used. The component can be appropriately adjusted by those skilled in the art without departing from the object of the present invention.

The resin composition according to the present invention can be prepared by a conventionally known method, by adding each component and other additives in necessary amounts, and kneading using a training machine such as a ribbon mixer, a dumbler mixer, and a single screw or twin screw extruder. Method may be used, but is not particularly limited in the present invention.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples. The following examples are only illustrative of the present invention and do not limit the scope of protection of the present invention.

< Example  1 to 4 and Comparative Example  1 to 5>

Polypropylene Resin Composition Preparation

According to the composition ratio shown in Table 1 below, the propylene propylene homopolymer and the α-olefin copolymer were kneaded in a Henschel mixer at 100 rpm for 10 minutes to prepare a propylene resin. An organic peroxide was added to the propylene resin, and 0.05 wt% of tetrax [methylene (3,5-ditetrabutyl-4-hydroxy) hydrocinnameth] methane, an antioxidant, to the whole resin composition, tris (2, 0.05 wt% of 4-di-tetrabutyl-phenyl) phosphite and 0.05 wt% of calcium stearate were kneaded at 100 rpm in a Henschel mixer for 10 minutes in addition to the propylene-based resin, followed by a temperature gradient from 160 DEG C to 220 DEG C with a twin screw extruder. And extruded, and then cooled and solidified to obtain a pellet-like resin composition.

Configuration
(weight%)
Example Comparative Example One 2 3 4 One 2 3 4 5 A PP-1 85 85 85 85 96 60 PP-2 80 80 80 B EP-1 15 EP-2 15 EP-3 15 20 15 20 4 40 20 C Organic peroxide 0.3 0.3 0.3 0.5 - 0.005 0.5 0.5 2.5

The components used in Examples 1-4 and Comparative Examples 1-5 of Table 1 are as follows.

 (A) Crystalline Propylene Homopolymer

PP-1 (crystalline propylene homopolymer 1): homopolypropylene (HJ500) with a melt index of 12 g / 10 min

PP-2 (crystalline propylene homopolymer 2): homopolypropylene with a melt index of 40 g / 10 min (HI831P)

(B) α-olefin copolymer

EP-1 (ethylene-butene copolymer): 1-butene content 7 wt%, melt index 4.3 g / 10min, density 0.92 g / cm ³ (4141C)

EP-2 (ethylene-hexene copolymer): Using metallocene catalyst, 1-hexene content is 7% by weight, melt index is 2.1 g / 10min, density is 0.92 g / cm ³ (7020F)

EP-3 (ethylene-octene copolymer): 6.5-% by weight of 1-octene, 2.0 g / 10min of melt index, 0.92 g / cm ³ (2045, Exxon)

(C) Organic peroxide

Di (4-t-butylcyclohexyl) peroxydicarbonate (P-100) with a purity of 97%

* Density measured at 25 ° C and melt index as ASTM D1238 *

< Experimental Example > Specimen Preparation and Property Evaluation

Each resin composition prepared in Examples and Comparative Examples was made of an ASTM Family 4 specimen and 2T sheet using an injection machine. The injection machine used was Samsung Kleukner FM110TON, and the injection conditions were 30 ℃, 190 ℃, 210 ℃, 210 ℃ and 210 ℃ (temperature of nozzle) and fixed at 60 ℃ (mould temperature). , Injection pressure was carried out in the range of 50 ~ 120 bar. The injected specimen was left at room temperature (23 ° C.) for 72 hours and then melt index, Izod impact strength, flexural modulus, and whitening resistance were measured as follows. The results are shown in Table 2 and Table 3.

Property evaluation method

(1) Melt Flow Index Measurement: ASTM D1238, 230 ℃, 2.16kg

(2) Flexural modulus: ASTM D790

(3) Izod impact strength: ASTM D256

(4) whitening resistance and sheet appearance:

After producing a 100mm × 100mm × 2mm sheet using an injection molding machine, after 72 hours, 1 kg of weight (25 mm diameter) was dropped from a height of 50 cm, and the diameter of the whitening area at the dropping point was measured. It was. Appearance evaluated the appearance defects, such as the gel of a sheet-like injected, or yellowing.

Configuration Example
One Example 2 Example 3 Example 4 Melt Index
(g / 10 min) 10.5 9.4 9.4 36 Flexural modulus
(kgf / cm ² ) 15500 15600 15900 15100 23 ℃ Izod Shock
Strength (kgf.cm/cm) 5.7 6.2 6.3 6.9 -20 ℃ Izod Impact Strength (kgf.cm/cm) 2.2 2.5 2.3 2.5 Whitening resistance (mm) 1.5 1.7 1.6 2.2 Sheet exterior Good Good Good Good

Configuration Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Melt Index
(g / 10 min) 9.6 37 11.5 7.1 33 Flexural modulus
(kgf / cm ² ) 15700 14900 16700 12200 14600 23 ℃ Izod impact strength
(kgf.cm/cm) 4.4 4 2.5 7.6 6.0 -20 ℃ Izod impact strength
(kgf.cm/cm) 2 1.9 1.8 3.2 2.0 Whitening resistance (mm) 1.8 2.1 One 12.2 2.5 Sheet exterior Good Good Good Good Bad

As shown in Table 2 and Table 3, it can be seen that Examples 1, 2 and 3 containing 0.3% by weight of organic peroxide, respectively, compared to Comparative Example 1 containing no organic peroxide, the impact strength was greatly improved. At the same time, it can be seen that the flexural modulus representing the rigidity of the resin is equivalent or slightly higher.

On the other hand, Comparative Example 2 containing 0.005% by weight of organic peroxide is significantly lower than the impact strength compared to Example 4 containing 0.5% by weight, Comparative Example 5 does not appear to improve the physical properties compared to Example 4, appearance defect characteristics This was observed. Therefore, it can be seen that the impact strength can be improved when the polypropylene resin composition according to the present invention contains 0.01% by weight or more of organic peroxide, and when it contains more than 2.0%, it is understood that appearance defects are observed. Can be.

In addition, with reference to the content of the α-olefin copolymer, Comparative Example 3 and Comparative Example 4, when the content of the α-olefin copolymer is less than 5% by weight, the impact strength is very low, α-olefin-based air When the coal content is 35% by weight or more, it can be confirmed that a problem occurs in stiffness and whitening.

As mentioned above, it can be seen that the polypropylene resin composition of the present invention has improved physical properties such as impact strength and whitening resistance. Therefore, the polypropylene resin composition of the present invention can provide a vehicle finishing material and packaging material that can satisfy safety and aesthetic effects at the same time.

Claims (6)

Propylene-based resins comprising 80-95% by weight of crystalline propylene polymer and 5-20% by weight of α-olefin copolymer; And
It comprises 0.01 to 2.0% by weight of organic peroxide relative to the propylene resin,
The organic peroxide is diethyl peroxy dicarbonate, dipropyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, dibutyl peroxy dicarbonate, ethylhexyl peroxy dicarbonate, dioctyl peroxy dicarbonate, di (4-t-butylcyclohexyl A polypropylene resin composition, characterized in that at least one member selected from the group consisting of peroxydicarbonate, dimyrisil peroxydicarbonate, and dicetyl peroxydicarbonate.
The method of claim 1,
The crystalline propylene polymer is a polypropylene resin composition, characterized in that the melt index is 0.1 ~ 500 g / 10min (ASTM D1238).
The method of claim 1,
The α-olefin copolymer is a polypropylene resin composition, characterized in that it comprises one or more of the copolymers of α-olefin monomers having 2 to 20 carbon atoms.
The method of claim 1,
The α-olefin copolymer is a propylene-α-olefin copolymer or ethylene-α-olefin copolymer, characterized in that the polypropylene resin composition.
The method of claim 1,
The α-olefin copolymer has a density of 0.90 to 0.93 g / cm ³ (25 ℃), polypropylene resin composition.
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