KR20110076341A

KR20110076341A - A polyolefin resin composition

Info

Publication number: KR20110076341A
Application number: KR1020090133025A
Authority: KR
Inventors: 김정신; 양현성; 이창헌
Original assignee: 현대이피 주식회사
Priority date: 2009-12-29
Filing date: 2009-12-29
Publication date: 2011-07-06

Abstract

PURPOSE: A polyolefin resin composition is provided to ensure excellent impact resistance and ductility according to temperature change and to enable use as automobile interiors of automobile air bag chute. CONSTITUTION: A polyolefin-based composite resin composition comprises 30~70 weight% of polypropylene resins, 20~60 weight% of ethylene-α-olefin copolymers, 1~20 weight% of polyethylene resins, and 1~20 weight% of inorganic filler. The polypropylene resin is at least one kind selected from a propylene homopolymer, propylene ethylene copolymer and highly crystalline polypropylene. The melt index is 0.5~100 g/10 minute. The inorganic filler is talc in which an average particle size is 0.5~10 micron.

Description

Polyolefin Composite Resin Composition {A Polyolefin Resin Composition}

The present invention relates to a polyolefin-based composite resin composition, the polyolefin-based composite resin composition of the present invention is excellent in impact strength, tensile strength and ductility at low and high temperatures can be usefully applied to automobile air bag chute (chute).

Recently, the automotive industry is striving to improve automobile fuel economy in line with the global trend of reducing carbon dioxide emissions. As a result, the lightweight design of automobiles is suggested as one way, and many automobile parts are used as plastic parts instead of steel. Especially, polypropylene, which is characterized by low specific gravity, excellent moldability, heat resistance, and chemical resistance, has already been used as a bumper, It is widely used as a material for instrument panels.

Air bag chute requires the impact resistance against high pressure when deploying the air bag, and the ductility property for the smooth deployment of the chute door, especially in high temperature (80 ~ 90 ℃) and low temperature (-20 ~ -40 ℃) It is a reality that it is not easy to implement the above characteristics as a polypropylene-based composite material. In the existing domestic airbag market, the chute door was used exclusively for steel insert products, and recently, covers and panels have been spreading.

In recent years, various research and development achievements have introduced polypropylene-based composite materials having excellent stiffness and low temperature impact strength. For example, the total amount of homopolypropylene component and copolymer component is 100%, and the content of homopolypropylene component is 40. Resin for airbag cover integrated inpanel having 50% to 10% talc content (Japanese Patent Laid-Open No. 2006257259), glass transition temperature of less than -45 ° C, Shore A hardness of 80 to 20 and Mooney viscosity ( Mooney Viscosity, ML1 + 4, 100 ℃) A thermoplastic resin having a content of 30 to 120 of 5 to 30%, a content ratio of propylene and ethylene resin of 0.5 to 3.0, and a bending elastic modulus of 300 MPa or more. Patent No. 2006257330) and the like are known.

However, in the above-described composition, in the case of the resin disclosed in Japanese Patent Laid-Open No. 2006257259, a stiffness change occurs in the long-term heat test, there is a problem that the impact resistance is lowered. In addition, the resin disclosed in Japanese Patent Application Laid-Open No. 2006257330 has a favorable effect on the smooth chute deployment at low temperatures, but at a high temperature there are disadvantageous problems such as tearing of the door and swelling of the chute and airbag coupling portion. .

As a result, it is especially applicable to air bag chute, which has excellent impact strength, ductility, and hinge characteristics at high and low temperatures, and has a high demand for materials for automobile interior materials having excellent dimensional stability due to low molding shrinkage rate and low linear expansion coefficient after injection. It is becoming.

Accordingly, the present inventors have attempted to solve the above problems, in the case of polyolefin composite resin composition comprising a polypropylene resin, ethylene-α-olefin copolymer, polyethylene resin and inorganic filler, chute departure and crack at high and low temperatures The present invention has been accomplished by knowing that it can exhibit its properties without.

Accordingly, an object of the present invention is to provide a resin composition useful as an automotive interior material such as a car airbag chute by improving the impact resistance and ductility characteristics according to temperature change as a polyolefin composite resin composition including a polyethylene resin.

The present invention is characterized by a polyolefin composite resin composition comprising a polypropylene resin, an ethylene-α-olefin copolymer, a polyethylene resin, and an inorganic filler.

Since the polyolefin composite resin composition of the present invention has excellent impact resistance and ductility characteristics according to temperature change, it can be applied to an integrated airbag chute to replace a chute used by inserting steel and fabric into a conventional chute door. This can significantly reduce the manufacturing process and contribute to cost reduction.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a polyolefin composite resin composition comprising a polypropylene resin, an ethylene-α-olefin copolymer, a polyethylene resin and an inorganic filler.

The polypropylene resin is used as a matrix of the composition, at least one selected from a propylene homopolymer, a propylene ethylene copolymer, and a highly crystalline polypropylene, and preferably, three kinds are mixed to meet the required performance. . The amount of polypropylene resin is preferably 30 to 70% by weight, but if the amount is too small, there may be a problem that the chute tears at high temperatures, on the contrary, too much may be broken at low temperatures.

Propylene homopolymers have an isotactic index of 94 to 97% by C13-NMR measurement and a melt flow index of 0.5 to 100 g / 10 min at a temperature of 2.16 kg and 230 ° C. .

The propylene ethylene copolymer is preferably a rubber content of ethylene-propylene of 0.5 to 30% by weight and a melt flow index of 0.5 to 100 g / 10 minutes, ethylene 1 to 50% by weight, propylene 50 to 99% by weight It is good to have the features.

Highly crystalline polypropylene has an isotactic index of more than 98.5% by C13-NMR measurement and a melt flow index of 0.5 to 100 g / 10 minutes, and is preferably a propylene homopolymer or propylene and C2 to Preference is given to using copolymers with C10 monomers. At this time, the C2 ~ C10 monomer content of less than 10 mol% should be used to maintain the impact resistance and rigidity balance of the highly crystalline polypropylene.

The ethylene-α-olefin copolymer is a rubber component copolymerized under a metallocene catalyst and is used as an impact modifier, and an ethylene-propylene copolymer rubber (EPR), an ethylene-butene copolymer rubber (EBR) and an ethylene-octene copolymer One or more selected from rubber (EOR) can be used. The amount of the ethylene-α-olefin copolymer used in the composition of the present invention is preferably 20 to 60% by weight, but if the amount is less than 20% by weight, there may be a problem that the impact strength is lowered. There may be a problem of this deterioration.

When butene or octene is selected as the α-olefin, the content of butene or octene is preferably 20 to 50% by weight in the ethylene-α-olefin copolymer, and more preferably 30 to 45% by weight. The Mooney viscosity of the ethylene-butene copolymer rubber or the ethylene-octene copolymer rubber is preferably 5 to 60 ML 1 + 4 at 121 ° C, and more preferably 20 to 40 ML 1 + 4. Too low may cause deterioration of physical properties, and too high may result in poor workability. In addition, the glass transition temperature of the ethylene-butene copolymer rubber or ethylene-octene copolymer rubber is used in the 50 ~ -65 ℃, if the glass transition temperature is higher than -50 ℃ low temperature impact resistance, -65 ℃ If lower, there may be a problem that the rigidity and heat resistance is lowered.

In the case where propylene is selected as the α-olefin, it is preferable that the propylene content is 20 to 50% by weight in the ethylene-propylene copolymer rubber. The ethylene-propylene copolymer rubber has a melt index of 0.5 to 6.0 g / 10 min (230 ° C., 2.16 kg), and has a Mooney viscosity of 5 to 70 ML 1 + 4, preferably 15 to 50 ML 1 + 4. Good to do. If the Mooney viscosity is less than 5, there may be a problem in impact resistance, and if it exceeds 70, moldability may be lowered.

The polyethylene resin is used to improve the impact strength and hinge properties, high density polyethylene (HDPE, density 0.941 g / cc or more), low density polyethylene (LDPE, density 0.910 ~ 0.925 g / cc) and linear low density polyethylene (LLDPE, density 0.910) ~ 0.925 g / cc) is used one or more selected, the amount is preferably 1 to 20% by weight. If the amount is too small, there may be a problem that the hinge portion is easily torn when the door is deployed, and if too large, the compatibility is poor, which may cause gas defects and cracks in the appearance of the product during injection molding. Polyethylene has low compatibility with polypropylene, but when rubber components such as ethylene-propylene copolymer are added, ethylene-propylene copolymer acts as a dispersant on the surface of polyethylene particles, acting as a compatibilizer, so that impact strength and The hinge characteristic can be increased.

The inorganic filler is added to the stiffness reinforcement, preferably talc is used, and optionally, with talc, silica, olastonite, mica, calcium carbonate, barium sulfate, calcium carbonate, magnesium oxide, At least one selected from calcium silicate, magnesium whiskers, glass fibers, and glass bubbles may be used. The average particle size of talc is preferably in the form of a plate shape of 0.5 to 10 ㎛, if the average particle size is less than 0.5 ㎛ there may be a problem that productivity is reduced, if the particle size exceeds 10 ㎛ and overall mechanical properties and Mold shrinkage may be a problem. The content of the inorganic filler is preferably 1 to 20% by weight, and if the content is too small, there may be a problem that the chute is torn at high temperatures, on the contrary, if too much, the rigidity is increased to be broken at low temperatures.

In addition to the four essential components, the resin composition of the present invention may further include additives such as antioxidants, heat stabilizers, and dispersants in order to improve performance and processing characteristics of the molded article.

The present invention is a polyolefin composite resin composition comprising a polyethylene resin, by newly configuring a series of compositions, such as using a specific ratio of polyethylene resin, the impact resistance and ductility characteristics in the high temperature and low temperature environment, which was a problem of the conventional polyolefin composite resin Therefore, it can be usefully applied to automobile interior materials such as airbag chute.

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.

Examples 1 to 3

After mixing the raw materials using a super mixer with the component contents shown in Table 1 below, the ratio of 40 mm in diameter and the length and diameter (L / D) is 52 to 200 to 400 ° C. using a twin screw extruder. After preparing the compound on the pellet (pellet) at the rotational speed of rpm, using the injection molding machine (model: LGE110, LS Cable) injection molding the resin composition at a cylinder temperature of 220 ℃ and a mold temperature of 50 ℃ to prepare a test piece It was.

Comparative Example 1

A composition was prepared in the same manner as in Example 1, but containing no polyethylene resin.

Comparative Example 2

A composition was prepared in the same manner as in Example 1, but containing no inorganic filler.

division Example (% by weight) Comparative example (% by weight) One 2 3 One 2 A PP-1 40 - - - - PP-2 - - - 55 10 PP-3 - 40 40 - 33 B EOR 40 40 - - 50 EBR 10 10 - 40 - EPR - - 50 - - C PE-1 5 - - - - PE-2 - - - - 7 PE-3 - 7 7 - - D Inorganic filler 5 3 3 5 - PP-1: Highly crystalline polypropylene (Isotactic Index 98.5 or more, melt flow index 10 g / 10 min (230 ° C, 2,16 kg), average molecular weight 221000, ethylene 8% by weight)
PP-2: Propylene-ethylene copolymer (melt flow index 10 g / 10 minutes (230 ° C, 2,16 kg), average molecular weight 2100000, ethylene 8% by weight)
PP-3: propylene homopolymer (melt flow index 7 g / 10 min (230 ° C., 2,16 kg), average molecular weight 195000)
EOR: ethylene-octene copolymer rubber (Money viscosity 26 ML1 + 4, 121 ° C, octene 45 wt%)
EBR: ethylene-butene copolymer rubber (Mooney viscosity 7 ML1 + 4, 121 ° C., butene 42 wt%)
EPR: Ethylene-propylene copolymer rubber (Mooney viscosity 65 ML1 + 4, 100 ° C., propylene 50 wt%)
PE-1: linear low density polyethylene (melt flow index 4 g / 10 min (190 ° C, 2,16 kg), average molecular weight 195000)
PE-2: low density polyethylene (melt flow index 10 g / 10 min (190 ° C, 2,16 kg), average molecular weight 220000)
PE-3: high density polyethylene (melt flow index 25g / 10min (190 ℃, 2,16kg), average molecular weight 235000)
Inorganic filler: KOCH TALC (particle size 0.5 ~ 2 ㎛)

Physical property test

The test pieces prepared in Examples and Comparative Examples were tested by the following test methods, and the results are shown in Table 2 below.

1) Melt Flow Index Test

It measured at 230 degreeC and 2.16 kgf according to ASTM D-1238 method.

2) Tensile strength measurement test

According to ASTM D-638 method, the speed was measured at high and low temperatures in consideration of the amount of impact received during air bag deployment.

Specimen size: 13 X 3 mm

Room temperature (23 ℃) test condition: 50 mm / min, gauge length: 50 mm

High temperature (85 ° C) and low temperature (-30 ° C) test conditions: 500 mm / min, gauge length: 50 mm

3) Flexural modulus measurement test

In accordance with the ASTM D-790 method, it was measured by increasing the speed at high and low temperatures in consideration of the amount of impact received during air bag deployment.

Specimen size: 12.7 x 127 x 6.4 mm,

Room temperature (23 ℃) test conditions (crosshead speed): 28 mm / min,

High temperature (85 ° C) and low temperature (-30 ° C) test conditions (crosshead speed): 200 mm / min

4) Heat deflection temperature measurement test

It measured by ASTM D-648 method.

Specimen size: 12.7 x 127 x 6.4 mm, load value used in test conditions: 4.6 kgf

5) Izod impact strength test

It measured by ASTM D-256 method.

Specimen size: 63.7 X 12.7 X 3 mm

division Example Comparative example One 2 3 One 2 Melt flow index
(g / 10 min) 4.6 4.8 4.2 9.5 4.8 85 ℃ The tensile strength
(kgf / cm ² ) 178 196 192 150 188 Flexural modulus
(kgf / cm ² ) 824 908 884 1006 1014 23 ℃ The tensile strength
(kgf / cm ² ) 96 107 89 118 139 Flexural modulus
(kgf / cm ² ) 3142 3691 3452 4474 5568 -30 ℃ The tensile strength
(kgf / cm ² ) 206 219 206 252 276 Flexural modulus
(kgf / cm ² ) 12905 13216 13162 14005 15261 Heat deflection temperature (℃) 52 52 50 52 55 Impact strength
(kg cm / cm) 23 ℃ 72 74 78 63 74 -30 ℃ 50 48 52 36 48

From the results of Table 2, the resin compositions of Examples 1 to 3, although the tensile strength at room temperature is slightly lower than Comparative Examples 1 to 2, it can be seen that the impact strength is excellent, and in particular, the flexural modulus is excellent despite the temperature change. On the other hand, when only ethylene-octene rubber is added to the propylene ethylene copolymer without adding polyethylene as in Comparative Example 1, it can be seen that the impact strength is decreased at low temperatures and the tensile strength is decreased at high temperatures. In the case of excellent tensile strength, but it can be seen that there is a problem that the flexural modulus becomes too high at low temperature. Therefore, the composite resin composition according to the present invention was excellent in tensile strength at high temperature to prevent the chute from tearing and excellent impact strength and flexural modulus at low temperature was found to have an excellent effect of preventing the chute from breaking.

Airbag Deployment Experiment

355 g of the product was prepared by injection molding the composition of Example 1 and Comparative Example 1 under the general conditions of molding temperature of 190 to 230 ° C, maximum injection pressure of 85 Mpa, and cycle time of 80 seconds to evaluate the airbag development test according to temperature. Afterwards, the result of the development experiment was left for 3 hours at low temperature (-20 to -40 ° C.) and high temperature (80 to 90 ° C.) after vibration welding with an instrument panel, and the results are shown in Table 3 below.

Temperature Shell fish occurrence
(Max.8mm) Suit door
Departure Instrument
panel
Crack presence Vibration Fusion Part
Departure Example 1 High temperature (85 ℃) clear clear clear clear Room temperature (23 ℃) clear clear clear clear Low temperature (-30 ℃) clear clear clear clear Comparative Example 1 High temperature (85 ℃) clear Chute exit clear clear Room temperature (23 ℃) clear clear clear clear Low temperature (-30 ℃) clear Chute exit clear clear

As shown in Table 3 above, it can be seen that Example 1 in which polyethylene is added is superior to Comparative Example 1 in which polyethylene is not added.

As a result, the polyolefin-based composite resin composition containing polyethylene showed excellent properties in impact resistance and hinge effect despite temperature change, and thus it was confirmed that the polyolefin-based composite resin composition had excellent effects in airbag deployment.

Claims

30 to 70 wt% polypropylene resin;

20 to 60% by weight of ethylene-α-olefin copolymer;

Polyethylene resin 1-20% by weight; And

Inorganic filler 1 to 20% by weight;

Polyolefin-based composite resin composition comprising a.

The polyolefin composite resin composition of claim 1, wherein the polypropylene resin is at least one selected from a propylene homopolymer, a propylene ethylene copolymer, and a highly crystalline polypropylene, and has a melt index of 0.5 to 100 g / 10 minutes. .

The method of claim 1, wherein the ethylene-α-olefin copolymer is at least one selected from ethylene-propylene copolymer rubber, ethylene-butene copolymer rubber and ethylene-octene copolymer rubber, and the content of propylene, butene or octene is Polyolefin composite resin composition, characterized in that 20 to 50% by weight.

The polyolefin-based composite resin composition of claim 1, wherein the polyethylene resin is at least one selected from high density polyethylene, low density polyethylene, and linear low density polyethylene.

The polyolefin-based composite resin composition according to claim 1, wherein the inorganic filler is talc having an average particle size of 0.5 to 10 µm.

The method of claim 1, wherein the inorganic filler is a talc and at least one selected from silica, olastonite, mica, calcium carbonate, barium sulfate, calcium carbonate, magnesium oxide, calcium silicate, magnesium whisker, glass fiber and glass bubble Polyolefin-based composite resin composition comprising a.