KR19990033557A - Polyolefin composite resin composition for automobile interior - Google Patents

Abstract

The present invention is excellent in mechanical stiffness, impact resistance and heat resistance, and while maintaining all these properties, in particular, the fluidity is extremely improved, and the injection moldability is excellent, the shrinkage ratio after injection molding is small, and the coefficient of linear expansion and deflection by heat (힛쌕, The present invention relates to a polyolefin composite resin composition having a small heat sag) and excellent dimensional stability, and more specifically, 40 to 80 wt% of a crystalline ethylene-propylene copolymer having a content of about 0.5 to 35 wt% of ethylene-propylene rubber; 2 to 25 wt% of an ethylene-α-olefin copolymer rubber having an α-olefin content of 20 to 50 wt%; 15-45 weight% of inorganic reinforcing materials which are needle-like calcium-meth-silicate-based ulastonite; The present invention relates to a polyolefin-based composite resin composition for automobile interior materials containing an additive of 0.1 to 5% by weight, and a component for automobile interior materials manufactured using the same.

Description

Polyolefin composite resin composition for automobile interior

The present invention is excellent in mechanical stiffness, impact resistance and heat resistance, and while maintaining all these properties, in particular, the fluidity is extremely improved, and the injection moldability is excellent. The present invention relates to a polyolefin-based composite resin composition for automobile interior materials having low heat sag) and excellent dimensional stability.

Thermoplastic resins, in particular, polyethylene and polypropylene, which are polyolefin resins, have low specific gravity and low price compared to other resins. They are excellent in mechanical properties and processability, so they are widely used not only for processing general-purpose plastic products but also for automobile, electronics, and aerospace industries. It is a resin. However, polyolefin resins have limitations in physical properties that can be expressed by themselves, and thus are difficult to apply to fields requiring special functions. In order to overcome these drawbacks, polyolefin-based composite resins have been developed to blend different kinds of resins or add mineral filters to give new functions, and have been applied to various fields that were not applicable to conventional polyolefin resins alone. In particular, polyolefin resins are based on Japanese polypropylene, and ethylene-α-olefin copolymers or elastomers, which are impact reinforcing materials, or inorganic fillers are added as rigid reinforcing materials, thereby expressing the necessary physical properties. It is widely used as a component. In addition, a variety of methods for improving various physical and thermal properties by changing the types of polypropylene resins and various types of impact reinforcing materials and rigid reinforcing materials have been proposed, and have been put into practical use.

In general, a composite resin refers to a material that has a new function that cannot be realized by the polymer itself by melt kneading a filler or reinforcing material using a kneader or an extruder with a polymer as a base material. In this case, the types, properties, sizes, and contents of the resins, fillers, or reinforcements should be selected according to the application and characteristics of the application field.In particular, since the physical properties are greatly affected by the change in processing conditions, Proper selection of processing equipment and processing conditions is essential to maintain the properties and improve the properties of the fillers. In addition, additives such as heat stabilizers and weather stabilizers for preventing the phenomenon of deterioration of physical properties due to deformation and aging of the resin in high temperature and high pressure atmosphere in the extruder or for expressing specially required properties after molding are also complex. It is an important variable in determining the properties of the resin. In addition, there is an interface between components between raw materials of different properties such as a polymer base material, a filler, and an additive, and the properties of the composite resin depend on the size of the interface adhesive force at this interface. Attention should be paid to the processing conditions.

Resin mainly used in the manufacture of automobile interior parts and electronic components, the acrylonitrile-butadiene-styrene copolymer, the alloy of polycarbonate / acrylonitrile-butadiene-styrene copolymer, polycarbonate / polybutylene-tere Phthalate alloys, polyamides, polyurethanes, and the like. However, among these resins, polyamide is difficult to be replaced by polyolefin composite resin because of its large difference in mechanical and thermal properties compared to polyolefin composite resin. However, the remaining resins except polyamide can be replaced by polyolefin composite resins in terms of weight reduction, cost reduction, and recycling of automobiles.

In order for the polyolefin-based composite resin to replace the above-mentioned resins, it should be excellent in high rigidity, high impact resistance, high heat resistance, dimensional stability, and scratch resistance. In addition, since the thickness of parts tends to be thinner according to the light weight of automobiles and light weight of parts, moldability should be extremely excellent, and the molding time of parts should be short in terms of cost reduction and productivity improvement. In addition, the parts should be excellent in paintability and appearance after molding depending on the paint type or unpainted type. However, the polyolefin-based composite resin composition that satisfies the above requirements as yet has not been developed.

Among the development trends of polyolefin-based composite resin compositions used for molding large parts such as instrument panels for automobile parts, development of low shrinkage / low expansion coefficient materials is a big part. The most representative property of raw materials for automobile parts is the stiffness of raw materials, which is expressed by flexural modulus and surface hardness. It is also closely related to other physical properties such as tensile strength, elongation, impact strength, density, heat deformation temperature, and coefficient of linear expansion. have.

Instrument panels have a larger surface area than relatively thin thicknesses, which can cause the molded parts to bend or sag if the raw material is not sufficiently rigid. Recently, the thickness of molded products tends to become thinner in terms of weight reduction of vehicles and raw material reduction, and thus, development of raw materials with higher flexural modulus is required. In addition, due to the improvement of the flexural modulus, as well as the assembly properties with the vehicle body and the dimensional stability of the molded article itself, a raw material having a small coefficient of linear expansion or heat sag is required. Basically, plastics have a coefficient of linear expansion that is 4 to 8 times larger than that of steel, so that the molded product sags or distorts depending on the climate or temperature after assembly with the body. In an effort to reduce this, composite products containing polypropylene, the basic resin, and inorganic fillers selected appropriately for rubber have been developed. However, the addition of the inorganic filler can reduce the coefficient of linear expansion and improve the flexural modulus. However, the impact strength at low temperatures is lowered. Therefore, the content of the filler must be properly adjusted to achieve harmony between the physical properties. In addition, the development of products with low shrinkage is required to satisfy the requirements, such as the ease of design of the mold for molding the product, the stability of the coating and dimensional stability, and the need for less post deformation after molding.

Japanese Patent No. 59-47252 is a well-known patent concerning the manufacturing method of the polyolefin composite resin composition used for the shaping | molding of automobile parts, In this patent, the ethylene-propylene aerial whose melt index is 8-30 g / 10min. Ethylene-propylene copolymer rubber with coalescence and melt index of 0.1 to 7 g / 10 min, ethylene content of 10 to 25% by weight, granular inorganic filler with an average particle size of 2 μm or less, and fragment inorganic filler with an average particle size of 5 μm or less 3 to 20 The high impact composite resin was manufactured using the weight%, but there was a limit to the improvement of the injection molding, which is not suitable for the molding of large injection moldings. Related patents include Japanese Patent Nos. 5-179081 and 11-129052.

The main object of the present invention is to improve the injection molding properties while improving the problem of the resin composition prepared by the above patents to balance the basic properties such as impact resistance, rigidity and heat resistance to improve the thickness of the molded article By making it thinner, it is possible to reduce the weight of the vehicle, and the appearance of the molded product is excellent after injection molding.In particular, the molding shrinkage rate and linear expansion coefficient are lowered to improve the assemblability of the molded product with the vehicle body and the dimensional stability of the molded product itself. Minimized, and further to provide a method for producing a polyolefin-based resin composition that can maximize the ease of design of the mold for molding the product. In particular, as a result of the present invention, it is possible to replace the alloys of polycarbonate / polybutylene terephthalate alloy and polycarbonate / acrylonitrile-butadiene-styrene copolymer, which are widely used for molding automobile interior parts such as instrument panels. It is to provide a method for producing a composite resin composition that can be.

Therefore, the present invention is 40 to 80% by weight of the crystalline ethylene-propylene copolymer of about 0.5 to 35% by weight of ethylene-propropylene rubber; 5-25 wt% of an ethylene-α-olefin copolymer rubber having an α-olefin content of 20-50 wt%; 15-45 weight% of inorganic reinforcing materials which are needle-like calcium-meth-silicate-based ulastonite; The present invention relates to a polyolefin composite resin composition containing an additive of 0.1 to 5% by weight, and an automotive interior component manufactured using the same.

In particular, the crystalline ethylene-propylene copolymer has an ethylene-propylene rubber content of about 0.5 to 35% by weight, and a crystalline ethylene-propylene copolymer having a melt index of 5 to 6 g / 10 minutes (230 ° C., 2.16 kg) ( 1 to 50% by weight of ethylene, 50 to 99% by weight of propylene), and the ethylene-α-olefin copolymer rubber has an ethylene-propylene copolymer rubber or octene content of 20 to 50% by weight in a propylene content of 20 to 30% by weight. At least one selected from the ethylene-octene copolymer rubber, which has a melt index of 0.1 to 15 g / 10 minutes (230 ° C., 2.16 kg), wherein the inorganic reinforcing material, which is urastonite, has an aspect bar of urastonite of 10 ~ 19, the average diameter of the particles is characterized in that 3 ~ 25μm. In addition, a trace amount of processing lubricant; Phenolic primary antioxidants; Phosphorus or amine secondary antioxidants; Carbon black; Hals UV stabilizer; One or more selected from amino silane-based or amino titanium-based coupling agents can be added.

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

The present invention relates to (A) crystalline ethylene-propylene copolymer of crystalline ethylene-propylene having a content of ethylene-propylene rubber of about 0.5 to 35% by weight and a melt index of 5 to 60 g / 10 minutes (230 ° C., 2.16 kg). 40-80 wt% of a copolymer (1-50 wt% of ethylene, 50-99 wt% of propylene), (B) an ethylene-α-olefin copolymer having an α-olefin content of 20-50 wt% 5 to 25 wt% of an ethylene-α-olefin copolymer rubber having a melt index of 0.1 to 15 g / 10 min (230 ° C., 2.16 kg), particularly preferably 20 to 50 wt% of a propylene content, and a melt index 0.1-25 g / 10 min (230 ° C., 2.16 kg), 5-25 wt% ethylene-propylene copolymer rubber or 20-30 wt% octene content, and melt index of 0.1-15 g / 10 min (230 ° C., 2.16 kg) Ethylene-octene copolymer rubber containing at least one selected from 5 to 30% by weight, and (C) as an inorganic reinforcing material for rigid reinforcement, needle-like calcium-meth-silicate-based ulasto It was used as a byte, wherein using wollastonite has an aspect ratio of 10 to 19 was used, and 15 to 45% by weight, in that the average diameter of the particles 3 ~ 25μm. (D) As an additive, a coupling material was used to increase the adhesion strength between the inorganic reinforcing material and the crystalline ethylene-propylene copolymer, and the primary and secondary antioxidants and the above to prevent thermal decomposition of the resin during processing. A heat stabilizer was prescribed, and a UV stabilizer was prescribed to prevent degradation of the resin due to ultraviolet rays during weathering reinforcement and outdoor exposure. Carbon black and pigment were selectively formulated for color development and weather resistance.

Referring to the components used in the present invention in detail, the crystalline ethylene-propylene copolymer of component (A) is generally used under a combined catalyst with titanium trichloride and alkyl aluminum compounds called Ziegler-Natta type catalysts or titanium. It polymerizes with a compound, a magnesium compound, etc. The crystalline ethylene-propylene copolymer is used in an amount of about 1 to 50% by weight of ethylene and about 50 to 99% by weight of propylene, and about 40 to 80% by weight of about 0.5 to 35% by weight of ethylene-propylene rubber. It was. This polymer is a polypropylene with a melting point of 165 ° C, a polyethylene with a melting point of 120 ° C and a crystallinity of 20 to 30% as measured by a differential scanning calorimeter, a weight average molecular weight of 190,000 to 265,000, and a number average molecular weight. It is resin which is 37,000-50,000. Number average molecular weight and weight average molecular weight were measured using Gel Permeation Chromatography. The melt index is 5 to 60 g / 10 minutes (230 ° C., 2.16 kg). If the melt index is 5 g / 10 minutes or less, the moldability of the composite resin composition is inferior. If the melt index is 60 g / 10 minutes or more, the impact resistance of the composition is poor. do.

In particular, the component (A) comprises a resin in which a large amount of ethylene-propylene rubber is produced directly in the reactor by injecting an excessive amount of gaseous ethylene in the reactor in the production process of the ethylene-propylene copolymer. This resin is produced by producing a large amount of ethylene-propylene rubber directly in the reactor, and the propylene component is dispersed in the crystalline polypropylene matrix with a uniform particle size and is present in excess in the formed ethylene-propylene rubber. It has excellent compatibility with this matrix polypropylene, so it has excellent interfacial adhesion and eventually has improved impact strength.

Therefore, the use of this resin can significantly reduce the content of additionally added ethylene-α-olefin copolymer rubber for reinforcement of impact resistance, unlike in the case of a general composite resin composition, thereby producing a composite resin composition having excellent price competitiveness. It is possible to reduce the deviation between the lot of the product during production, it is possible to manufacture a product having uniform properties and performance.

Component (B) In the present invention, an ethylene-α-olefin copolymer was mainly used for impact reinforcement. As the α-olefin, 1-propylene, 1-butene, 1-hexene, 1-octene, etc. may be used, and may be selectively used depending on the use. In this case, the ethylene-α-olefin copolymer used is mainly polymerized using a Ziegly-Natta type catalyst, in particular, a vanadium-based or chromium-based catalyst. Ethylene-α-olefin copolymer containing 5 to 25% by weight of ethylene-α-olefin copolymer rubber having an α-olefin content of 20 to 50% by weight and a melt index of 0.1 to 15 g / 10 minutes (230 ° C., 2.16 kg). Used. As the ethylene-α-olefin copolymer rubber, ethylene-propylene copolymer and ethylene-octene copolymer rubber were mainly used. The ethylene-propylene copolymer rubber has a propylene content of 20 to 50% by weight and a melt index of 0.1 to 5 g / 10 minutes (230). 2.16 kg) was used. At this time, the ethylene-propylene copolymer high patterned viscosity was 19 ~ 85ML _{1 + 4} (100 ℃) and specific gravity of 0.86g / cm ³ copolymer rubber was used 5-25% by weight. Ethylene-octene copolymer rubber has a co-monomer octene content of 20-30 wt%, a melt index of 0.1-15 g / 10 min (230 ° C., 2.16 kg), and a pattern viscosity of 19-50 ml _{1+. 4} (121 DEG C) rubber was used at 5 to 20% by weight.

Component (C) In the present invention, as an inorganic reinforcing material for rigid reinforcement, needle-like calcium meta-silicate-based ulastonite was used, and the urastonite used herein had an aspect ratio of 10 to 19 and an average diameter of 3 particles. 15-45 weight% was used for -35 micrometers.

Component (D) In the present invention, additives are suitably formulated in order to improve physical properties of the resin composition and to improve heat resistance and weather resistance. As additives, primary or secondary antioxidants, UV stabilizers, processing lubricants and coupling materials are basically used to increase the adhesion sensitivity between inorganic reinforcing materials and crystalline ethylene-propylene copolymers. , An antistatic agent, a nucleating agent and the like were further added to prepare a resin composition.

In order to obtain the resin composition of the present invention, the raw materials are mixed using a Henschel Mixer, a Ribbon Blender, a V-Blender, or the like. Can be supplied directly to the processing machine, and the processing machine may be a single screw extruder, a twin screw extruder, or a twin screw extruder that can use a part of the extruder as a feed port in addition to a single feed port, depending on the characteristics of the raw material and the final composition. After melt mixing using a Kneader Mixer, a Benbury mixer, etc., pelletization was performed. Since the physical properties and performance of the resin composition may vary depending on the processing conditions and the type of processing equipment, in the present invention, the rotational speed of the screw and the extrusion are mainly used using a twin screw extruder that can use a part of the extruder as a supply port in addition to one supply port. The optimum processing conditions were selected by varying the amount and processing temperature, and the resin composition was prepared under these selected conditions.

The resin composition thus prepared was subjected to a constant moisture and volatile removal process to prepare injection or compressed specimens and to measure mechanical and thermal properties in accordance with the American Standard (ASTM). It was. The physical properties of the specimens were mainly by injection molding, and the injection specimens were used by the Korean Venus injection machine (model IDE90EN), and the cylinder temperature and the mold temperature were fixed at 200 ~ 230 ℃ and 50 ℃, respectively. The injection speed was used in the area where physical properties can be well expressed. The injection specimen for the measurement of physical properties was measured after leaving for 48 hours at 23 ℃, 50% RH (Relative Humidity, RH). Physical property measurement conditions are as follows.

(1) Melt index (Melt Index, MI): Measured by the method specified in ASTM D1238 (230 ° C, 2.16 kg), an automatic measuring device and a manual measuring device were used in parallel.

(2) Tensile strength and elongation: Measured by the method specified in ASTM D638 (Type I, cross-head speed = 50 mm / min).

(3) Flexural Strength and Flexural Modulus: Measured by the method specified in ASTM D790 (cross-head speed = 30 mm / min).

(4) Impact Strength: Measured at room temperature and low temperature (-30 ° C.) according to ASTM D256. The weight of the rotary weight is 5 pounds.

(5) Heat Deflection Temperature: Measured by the method specified in ASTM D648. The load is then 4.16 kg.

(6) Mold Shrinkage: It was measured by the method specified in ASTM D955.

(7) Coefficient of Linear Thermal Expansion (CLTE): The dimensional change was measured by varying the temperature in the range of -30 ~ 80 ℃ by the method specified in ASTM D696.

(8) Heat Sag: The strain value before and after holding the specimen of 110 (L) × 20 (W) × 3 (H) mm in parallel with the floor in the longitudinal direction and holding it in the oven at 120 ℃ for 1 hour. Measured.

The following table shows the raw material used in Examples and Comparative Examples.

(1) crystalline ethylene-propylene copolymer

(2) ethylene-α-olefin copolymer rubber

(3) inorganic reinforcing materials

(4) additive

Additives are commonly included in all composite resin compositions and include the following contents. In the present invention, the base content of each base additive was selected to add 2.0 wt% jointly to all the composite resin compositions.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, these examples do not limit the scope of the present invention.

EXAMPLES 1-6

To prepare a polyolefin composite resin in the composition shown in Table 1. The resin composition thus prepared was measured for the melt index, tensile strength, elongation, flexural modulus, impact strength, heat deformation temperature, coefficient of linear expansion, molding shrinkage and 힛쌕 by the method described above. Example Physical properties of the compositions are shown in Table 1.

[Comparative Examples 1-3]

To prepare a polyolefin composite resin in the composition shown in Table 1. In this case, the filler used was talc unlike the example. The resin composition thus prepared was measured for the melt index, tensile strength, elongation, flexural modulus, impact strength, heat deformation temperature, coefficient of linear expansion, molding shrinkage and 힛쌕 by the method described above. Physical properties of the Comparative Example compositions are shown in Table 1.

[Comparative Example 4]

The physical properties of the alloy resin (PC / ABS) of the polycarbonate / acrylonitrile-butadiene-styrene copolymer which are widely used in the molding of automotive interior parts for comparison with the performance of the composite resin produced by the present invention are also shown in Table 1. It was.

The effect of the present invention is to improve the problems of the modern resin composition to balance the basic properties such as impact resistance, stiffness and heat resistance while improving the injection moldability to make the thickness of the molded article to achieve a lighter weight of the vehicle, injection The appearance of the molded product is excellent after molding, and in particular, the molding shrinkage rate and linear expansion coefficient are lowered to improve the assemblability of the molded product with the car body and the dimensional stability of the molded product itself, and to minimize the post-forming and post-molding post deformation. It is to be able to provide a polyolefin-based resin composition that can maximize the design ease of. In addition, by using the resin composition of the present invention can replace the alloy of the polycarbonate / polybutylene terephthalate alloy and polycarbonate / acrylonitrile-butadiene-styrene copolymer that is widely used in the molding of automotive interior parts Will have.

Claims (6)

40 to 80 wt% of the crystalline ethylene-propylene copolymer having an ethylene-propylene rubber content of about 0.5 to 35 wt%; 5-25 wt% of an ethylene-α-olefin copolymer rubber having an α-olefin content of 20-50 wt%; 15-45 weight% of inorganic reinforcing materials which are needle-like calcium-meth-silicate-based ulastonite; Polyolefin-based composite resin composition for automotive interior containing an additive of 0.1 to 5% by weight. The crystalline ethylene-propylene copolymer according to claim 1, wherein the crystalline ethylene-propylene copolymer has a melt index of 5 to 60 g / 10 minutes (230 DEG C, 2.16 kg) (1 to 50% by weight of ethylene and 50 to propylene). Polyolefin-based composite resin composition for automobile interior materials characterized in that ~ 99% by weight). The method of claim 1, wherein the ethylene-α-olefin copolymer rubber is melted with at least one selected from ethylene-propylene copolymer rubber having a propylene content of 20 to 50% by weight or ethylene-octene copolymer rubber having an octene content of 20 to 30% by weight. Polyolefin-based composite resin composition for automobile interior, characterized in that the index is 0.1 ~ 15g / 10 minutes (230 ℃, 2.16kg). The polyolefin for automobile interior material according to claim 1, wherein the inorganic reinforcing material is acicular calcium-meth-silicate based ulastonite having an aspect ratio of ulastonite of 10 to 19 and an average diameter of particles of 3 to 25 µm. System composite resin composition. The method of claim 1, wherein the trace additive is a processing lubricant; Phenolic primary antioxidants; Phosphorus or amine secondary antioxidants; Carbon black; Hals UV stabilizer; A polyolefin-based composite resin composition for automobile interiors, characterized in that at least one member selected from amino silane-based and amino titanium-based coupling agents is added. Automobile interior parts manufactured using the polyolefin-based composite resin composition of claim 1.