KR20050123256A - A polypropylene resin composition for automobile interior materials - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition for automotive interior skin materials. More specifically, process oil and polypropylene wax may be added to a polypropylene copolymer, ethylene-octene rubber and ethylene-α-olefin copolymer rubber. In spite of the high content of rubber by master batch, it has excellent injection moldability without crosslinking of rubber components as well as excellent low temperature impact resistance, heat resistance, and no smell.Instrument Panel (Instrument Panel) The present invention relates to a polypropylene resin composition which can be used as a skin material, a door trim skin material or a pillar skin material.

Description

A polypropylene resin composition for automobile interior materials

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition for automotive interior skin materials. More specifically, process oil and polypropylene wax may be added to a polypropylene copolymer, ethylene-octene rubber and ethylene-α-olefin copolymer rubber. In spite of the high content of rubber by master batch, it has excellent injection moldability without crosslinking of rubber components as well as excellent low temperature impact resistance, heat resistance, and no smell.Instrument Panel (Instrument Panel) The present invention relates to a polypropylene resin composition which can be used as a skin material, a door trim skin material or a pillar skin material.

Currently, interior panels and door trims are used as single layer or three-layer structure (skin material / foaming material / core material). In the case of single layer structure, poor surface scratchability and low-grade appearance should be improved. In the case of the structure, the weakness of the single-layer structure can be compensated for, but the number of processes according to the three-layer structure is four times higher than that of the single-layer structure.

In the case of three-layer inpanel products, the skin is manufactured by vacuum forming, powder slush molding, and calendering molding, and in the case of core material, polycarbonate / acrylonitrile-butadiene / styrene terpolymer (PC / ABS) is injection molded. It is manufactured through the foam and the core material in the foaming mold and then polyurethane foaming. While reducing the number of these processes, it is urgent to develop a technology that can compensate for the weakness of the single-layer structure and give a feeling like a three-layer structure. As an alternative to the shortening of the process, an insert molding covering the skin material on the core material (Insert injection) can be considered. The emergence of the molding and the like molding method is an injection moldability problem of the soft resin for the skin material. In the case of this molding method, the skin layer is very thin (1-2 mm) in terms of the construction of the product, which is an important measure of how excellent the injection moldability of the material. Thermoplastic Vulcanizate, Styrene-Ethylene-Butadiene-Styrene, Polyurethane-based Elastomer, etc. may be used for the injection molding of the skin material. First, in the case of thermoplastic vulcanizates, a large amount of olefinic rubber is used for soft properties, so that the weakness of injection moldability is domaind through crosslinking of rubber components, so that a small amount of polypropylene becomes a fluidized bed to induce injection. Because of the crosslinking agent, the odor problem is severe, and the remaining amount of crosslinking agent causes discoloration during long-term heat test, making it difficult to cope with the policy of extending the warranty period of recent automobile companies. This is so expensive that it also has limitations of commercialization.

Therefore, in developing the skin material to be applied to the insert molding or similar injection technology without soft feeling and smell, the fluidity of the rubbers used for the soft feeling of the material is sufficiently secured to facilitate the injection moldability. Finding material composition and manufacturing methods is a challenge.

Accordingly, the present inventors use a polypropylene copolymer, ethylene-octene rubber and ethylene-α-olefin copolymer rubber master batch in a certain amount to solve the conventional problems, the automotive interior material is very excellent injection properties and soft feeling is maintained The present invention has been completed by developing a polypropylene resin composition for the skin material.

Accordingly, an object of the present invention is to provide a resin composition for automotive interior materials, panel trim, and peeling skin material having no odor and excellent hardness, flexibility, heat resistance, low temperature impact resistance, and injection molding.

In addition, the present invention has another object to provide a vehicle interior inpanel, door trim, peeling skin material and a manufacturing method using the resin composition.

The present invention

Per 100 parts by weight of the total resin composition,

(A) 1 to 20 parts by weight of a polypropylene copolymer;

(B) 40 to 70 parts by weight of the ethylene-α-olefin copolymer rubber master batch;

  100 parts by weight of the entire rubber masterbatch

 1) 30 to 60 parts by weight of ethylene-α-olefin copolymer rubber

 2) 5 to 20 parts by weight of polypropylene wax

 3) 20 to 40 parts by weight of paraffin-based processing oil

 4) 5 to 15 parts by weight of inorganic filler

(C) The polypropylene-based resin composition for automotive interior inpanel, door trim, and pillar skin material containing 10 to 20 parts by weight of ethylene-octene rubber.

In addition, the present invention is a method for manufacturing a car interior material inpanel, door trim, peeler skin material, the car interior material inpanel, door trim, peeler skin for manufacturing the resin composition on the core material by insert molding or similar injection molding Another method is the method of making ash.

In addition, the present invention includes an automobile interior material panel, a door trim, a peeling skin material manufactured by the above method.

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

The present invention provides a master component of a process oil and a polypropylene wax in a polypropylene copolymer, an ethylene-octene rubber and an ethylene-α-olefin copolymer rubber in an appropriate amount so that the rubber component is high despite the high rubber content. Not only has excellent injection moldability without crosslinking, but also has excellent low temperature impact resistance, heat resistance, and no smell. Polypropylene that can be used as an instrument panel, door trim, or pillar skin It relates to a system resin composition.

Hereinafter, each component of the resin composition in the present invention will be described in more detail.

The polypropylene copolymer (A) of the present invention is a homopolymer of propylene or a binary copolymer of propylene and an α-olefin having 2 to 10 carbon atoms of 2 to 10 carbon atoms, having a melt index of 10 to 100 g / 10 minutes (230 ° C). Phosphorus crystalline polypropylene is preferably used having a melt index of 30 g / 10 min (230 ° C., 2.16 Kgf).

The content of the polypropylene copolymer as the component (A) is used in an amount of 1 to 20 parts by weight, based on 100 parts by weight of the total resin composition, and if the content is less than 1 part by weight, there is a problem in moldability and heat resistance, and 20 parts by weight. If exceeded, there is a problem of rapid increase in hardness and low temperature impact.

Moreover, the resin composition of this invention can adjust hardness and fluidity using an ethylene-alpha-olefin copolymer rubber masterbatch.

In the ethylene-α-olefin copolymer rubber master batch of (B), in order to give a soft feeling, it is generally preferable to use rubber having a high molecular weight, but in the case of such high molecular weight rubber, injection moldability tends to decrease rapidly. In this case, the processing oil is generally used to increase the fluidity and control the hardness, and the amount is generally 1: 1 with rubber. However, increasing the amount of processed oil has a fatal weakness, which is relatively surface transition of the moving oil and the soaking becomes higher. In order to compensate for this weakness and increase the fluidity, the present invention used a polypropylene wax having excellent compatibility with the ethylene-α-olefin copolymer rubber to increase the fluidity. In addition, when using general rubbers and processed oils, a kneader or a Banbury mixer is used. In this study, first, an ethylene-α-olefin copolymer rubber having sufficient fluidity in a kneader or a Banbury mixer is used. After the master batch was prepared, the second extrusion was performed through the (A) and (C) components and the twin screw extruder to maximize the kneading property of the ethylene-α-olefin copolymer rubber, the process oil, and the polypropylene wax. The ethylene-α-olefin copolymer rubber of the present invention is used to reinforce impact resistance and lower hardness. The ethylene-α-olefin copolymer rubber is a copolymer of ethylene and an α-olefin having 2 to 10 carbon atoms, and α-olefins include propylene, butene, pentene, hexene, propene, octene and the like. As such ethylene-α-olefin copolymer rubber, ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), ethylene-octene rubber (EOR) and the like can be used. Among these, in the case of ethylene-octene rubber, the length of the side chain of octene which is a comonomer is long, and since it is excellent in impact resistance at low temperature, it can use especially preferably. As the ethylene-octene rubber, an octene content of 10 to 40% by weight, a Mooney viscosity of 20 to 50 (ML1 + 4, 121 ° C) may be used, more preferably an octene content of 20 to 35% by weight, It is good to use a thing with a Mooney viscosity of 25-50. That is, the ethylene-α-olefin copolymer rubber may be ethylene-propylene, ethylene-butene, ethylene-octene, etc., but in view of the low temperature impact portion of the present invention, ethylene-octene rubber (US Dupont-Dow Elastomers) Is preferably used.

The content of the ethylene-α-olefin copolymer rubber is preferably used in an amount of 30 to 60 parts by weight based on 100 parts by weight of the total composition of the master batch, and if the content is less than 30 parts by weight, the soft feeling and low temperature impact are lowered. If the amount is exceeded, the toughness and rigidity of the material is severely lowered.

Therefore, the present invention uses processed oil for flexibility (low hardness) and formability reinforcement. The processing oil penetrates the molecular chain of the rubber to straighten the chain, so that the processability is very good and the hardness is excellent. Such processed oil is a kind of softener. Softener is a generic term for rubber compounding oil which aims to increase the flexibility and processability of rubber and increase the volume, and is divided into process oil and extender oil. The branches are called process oils.

Processed oil is used to increase the workability, processability, and flexibility of rubber, and paraffinic, naphthenic, and aromatic oils are preferred, and paraffinic is preferable in terms of odor. Therefore, the use of the processing oil not only increases the processability of the impact resistant rubber having a high molecular weight, but is also advantageous in making a low hardness product of a desired level even with a low rubber content. That is, when the processing oil is introduced into the powder slush molding, it is expected to improve the melt rate relatively while maintaining impact resistance and low hardness.

The paraffinic oils include normal paraffine and iso-paraffins, and have little discoloration contamination and excellent odor in terms of rubber, while low in strength and excellent in compressibility, low temperature, and stain resistance. Is low. Naphthenic is intermediate between paraffin and aromatic and has good fouling resistance, low temperature property, processability, aging resistance, and cold resistance, but its tensile strength and elasticity are poor. In the case of the aromatic system, various physical properties are good, like naphthenic, but have a weak point in smell. Therefore, in terms of odor, which is one of the objects of the present invention, it is preferable to use paraffin system. Paraffin-based oils are of various types of 10 to 800 cSt (40 ° C.) depending on kinematic viscosity. Preferably, high molecular weight products of 400 to 600 cSt are used to prevent surface migration.

If the content of the processing oil is used in 20 to 40 parts by weight based on 100 parts by weight of the total composition of the rubber master batch, if the content is less than 20 parts by weight there is a problem that does not impart proper moldability to the rubbers, Process oil can transfer to the surface and cause serious contamination of the vehicle front glass.

In addition, an important component used to increase the fluidity of the (B) component ethylene-α-olefin copolymer rubber master batch is polypropylene wax, which is a phthalate-based compound used to increase the melting rate in polyvinyl chloride. Olefin waxes are generally used as processing aids because of their very low viscosity. Such polyolefin wax may be polyethylene or polypropylene wax, but since the resin composition of the present invention is polypropylene, it may be advantageous in terms of compatibility using polypropylene wax. Polypropylene waxes also differ in their properties as the base polypropylene is a single, binary, terpolymer. Currently, conventional polypropylene waxes are mainly produced by decomposing single or binary copolymers.

These polypropylene waxes are generally commercially available in the range of 50 to 1,000 cps (170 ℃, Brookfield), and products using between 50 and 800 cps (170 ℃, Brookfield) are considered when considering the effects on melt rate and physical properties. It is preferable.

The polypropylene wax is used in an amount of 5 to 20 parts by weight based on 100 parts by weight of the ethylene-α-olefin copolymer rubber master batch composition, and when the content is less than 5 parts by weight, the effect of increasing the melt index is less than 20 parts by weight. The hardness of the resin composition becomes high, making it difficult to maintain a soft feeling.

In addition, as an inorganic filler added to enhance the dimensional stability and heat resistance of the ethylene-α-olefin copolymer rubber master batch, and to improve productivity, talc, calcium carbonate, calcium sulfate, magnesium oxide, calcium starrate, mica, silica, calcium silicate, Types of clay, carbo black, and the like may be used, and preferably, talc or calcium carbonate may be used to improve productivity, and properties of the inorganic filler may be used to supplement properties. For example, the average particle diameter of talc is 2-20 mm, Preferably it is 3-7 mm. The content of the inorganic filler is 5 to 15 parts by weight, if the content is less than 5 parts by weight, there is a problem that the dimensional stability is not able to take action, and if it exceeds 15 parts by weight, there is a problem that the softness of the entire product falls.

Finally, (C), which is an important component in the present invention, is an ethylene-octene rubber having a high melt melt index and a low Mooney viscosity, and this component is an important component for improving injection moldability while maintaining low hardness, and preferably octene. A content of 10 to 30% by weight and a Mooney viscosity of 2 to 10 (ML1 + 4, 121 ° C) may be used, more preferably an octene content of 20 to 30% by weight and a Mooney viscosity of 2 to 5 It is good to use that. The preferred content of the ethylene-octene rubber is 10 to 20 parts by weight. In this case, when the content of ethylene-octene rubber is less than 10 parts by weight, the effect of increasing the fluidity is not very good, and when it exceeds 20 parts by weight, it has a weakness in that releasability is poor during injection molding due to low molecular weight.

As described above, the resin composition according to the present invention primarily reforms high molecular weight ethylene-α-olefin copolymer rubber through processing oil and polypropylene wax to improve injection moldability, and improves ethylene-octene rubber of high melt melt index. By use, the hardness of Shore 50 ~ 80 A, odorless, excellent flexibility, heat resistance, low temperature impact and injection moldability, and most components are olefin-based, there is no problem of containing odor and heavy metals.

Therefore, the resin composition of the present invention can manufacture the inpanel, door trim, and peeling skin material by insert injection molding or similar injection molding on the core material, so that the cost reduction through shortening the process can contribute to the olefin series. Due to the material composition of the odor, heavy metal content problems can be improved.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Examples 1-3

The polypropylene resin composition was prepared in the following compositions and contents. At this time, the conditions of each (A), (B), and (C) component are as follows.

(A): polypropylene terpolymer having a melt index of at least 35 g / 10 minutes,

(B): 25 parts by weight of octene, 50 parts by weight of an ethylene-octene copolymer having a Mooney viscosity of 35 and 30 parts by weight of a paraffinic processing oil having a kinematic viscosity of 500 cst (40 ° C) and a viscosity of 200 cps (170 ° C, Brookfield viscometer Ethylene-α-olefin copolymer rubber master batch prepared using kneader containing 10 parts by weight of polypropylene wax) and 10 parts by weight of talc having an average particle diameter of 5 μm.

(C): a resin composition obtained by mixing an ethylene-octene rubber having a Mooney viscosity of (ML1 + 4, 121 ° C) 5 and an octene content of 25% by weight in the following Table 1 in a tumbler mixer for 5 minutes Thereafter, extrusion and cooling and solidification were carried out using a twin-screw extruder at 190 to 220 ° C to obtain a pellet-like composition. Each composition obtained was measured for the flowability and the above evaluation items in the Spiral Flow mold to evaluate the moldability and the results are shown in Table 1 below.

Comparative Example 1

The components (A), (B) and (C) were prepared at the same time in the kneader without master batching of the component (B). .

Comparative Example 2

Of the components were prepared by excluding the component having a Mooney viscosity of 5 to maximize the fluidity and evaluated after molding in the same manner as in Example shown in Table 1 below.

Comparative Example 3

In the manufacturing process of the olefin rubber master batch (B), the content of polypropylene wax and ethylene-α-olefin copolymer rubber was lowered by 10 parts by weight, and instead, the content of the processing oil was increased, and then manufactured through a twin screw extruder. The results of evaluation after molding are shown in Table 1 below.

Comparative Example 4

Commonly used polypropylene resin was used.

Test Example

The physical property evaluation methods of the various compositions adopted in Examples 1 to 3 and Comparative Examples 1 to 4 were carried out by the following test method.

(1) Shore A hardness:

The test was conducted according to JIS K 6301 and measured on a 15 cm × 15 cm × 0.6 cm size specimen using a Shore hardness tester of Zwick, Switzerland. Retention time was 10 seconds.

(2) heat aging resistance:

Sheets formed by powder slush molding in a hot air circulation oven at 120 ° C. were evaluated for surface crack state and change rate of tensile strength after standing for 500 hours. The results are shown in Table 1 below.

(3) low temperature impact:

The sheet prepared by the powder slush molding method was fixed to a cup-type mold, and left standing for 4 hours in a chamber at -40 ° C. Then, a 50 mm diameter sphere and a mass of 5 kg were freely dropped at a height of 1 m. . It was evaluated that the low-temperature impact property was low when debris was formed during brittle behavior during fracture.

(4) smell:

The smell is cut into 10 cm × 10 cm × 1.5 cm sheets made of powder slush molding, put into a 4 liter sealed container, heated to 602 ℃ for 1 hour 20 minutes, cooled for 20 minutes, and then smelled. Measured. Odor evaluation was performed by five people, and the total number of people who evaluated odor was evaluated by subtracting from five. Normally, automobile companies wanted a level of 4 or better.

(5) Fogging Value:

The soaking odor was cut into a sheet made of powder slush molding into a 70 mm diameter circle, placed in a beaker, covered with a clean glass plate, and heated at 100 ° C. for 4 hours in a bath filled with silicone oil. After heating, the glass plate was measured with a hazemeter.

(6) Spiral Flow

Spiral Flow, a flow measurement method used in the present patent, is a mold manufactured in the form of FIG. 1 in a molding force 140TON injection machine, injection temperature 230 ℃, injection speed 15 mm / sec, injection pressure: 110/90 psi, injection time 15 sec . Metering: 50 mm, cooling water: The length which injected and flowed in 50 degreeC conditions was measured.

As shown in Table 1, Example 1 and Comparative Example 1 show a significant difference in fluidity depending on the presence or absence of pre-master batching, and as shown in Comparative Examples 2 and 3, depending on the presence of low ethylene viscosity and ethylene-octene rubber and polypropylene wax. It can be seen that there are many differences in the degree of fluidity. In addition, the increase in processed oil increased the litter, exceeding the automaker's requirements of 3.

As described above, the polypropylene resin composition for automobile interior skin materials of the present invention primarily mixes polypropylene wax, processing oil, and inorganic filler in ethylene-α-olefin copolymer rubber to maximize the fluidity and softness of the rubber. In addition to this, high flow and low viscosity viscosity ethylene-octene rubber and high flow polypropylene copolymer are mixed with a twin screw extruder to improve injection moldability, impact resistance and heat resistance, and have excellent soft feeling, no odor, and no heavy metals. Therefore, in the future, the application of polyvinyl chloride as an olefin-based material not only improves the environmental aspects, but the existing inpanel and door trim processes are more than three processes, whereas the present invention material enables the injection of the skin material to the core material. By use in insertable moldings and similar injection moldings It can contribute to cost reduction and productivity improvement by shortening the process.

Figure 1 shows the form of the mold for measuring the flowability.

Claims (9)

Per 100 parts by weight of the total resin composition, (A) 1 to 20 parts by weight of a polypropylene copolymer; (B) 40 to 70 parts by weight of the ethylene-α-olefin copolymer rubber master batch;  100 parts by weight of the total rubber masterbatch composition  1) 30 to 60 parts by weight of ethylene-α-olefin copolymer rubber  2) 5 to 20 parts by weight of polypropylene wax  3) 20 to 40 parts by weight of paraffin-based processing oil  4) 5 to 15 parts by weight of inorganic filler (C) Polypropylene-based resin composition for injection molding of automotive interior panels, door trims and fillers containing 10 to 20 parts by weight of ethylene-octene rubber. The resin composition according to claim 1, wherein the polypropylene copolymer is a homopolymer of propylene or a binary copolymer of propylene and 11 to 25 mol% of an α-olefin having 2 to 10 carbon atoms. The resin composition according to claim 1, wherein in the ethylene-α-olefin copolymer rubber master batch of (B), the ethylene-α-olefin copolymer rubber is a copolymer of ethylene and α-olefin having 2 to 10 carbon atoms. . The ethylene-α-olefin copolymer rubber is an ethylene-octene rubber, having an octene content of 10 to 40% by weight and a Mooney viscosity of 20 to 50 (ML1 + 4, 121 ° C). Resin composition. The resin composition according to claim 1, wherein the polypropylene wax of (B) has a viscosity of 50 to 800 cps (170 ° C). 2. The resin composition according to claim 1, wherein the processing oil of (B) is paraffin, aromatic or naphthenic processing oil having a kinematic viscosity of 10 to 800 cSt (40 占 폚). The resin composition according to claim 1, wherein the ethylene-octene rubber of (C) has an octene content of 10 to 30% by weight and a Mooney viscosity of 2 to 10 (ML1 + 4, 121 ° C). Polyethylene wax, process oil, and inorganic filler are primarily mixed with the ethylene-α-olefin copolymer rubber to form a rubber master batch (B), and the ethylene-octene rubber (C) and the polypropylene copolymer (A) are added thereto. A method for manufacturing an automotive interior skin material comprising mixing by a twin screw extruder and manufacturing by insert injection molding or similar injection molding. Automotive interior skin material prepared by the method of claim 8.