KR100578167B1 - A composition of polyolefin-based complex resin - Google Patents

Abstract

The present invention relates to a polyolefin composite resin composition, and more particularly, it is composed of a crystalline ethylene-propylene copolymer, an ethylene-α-olefin copolymer, and an inorganic reinforcing material having different ethylene content and melt index, respectively. Excellent impact resistance and heat resistance to maintain these characteristics, in particular to improve the fluidity extremely excellent injection moldability, low shrinkage after injection molding, low thermal expansion coefficient and heat sag (heat sag) due to low dimensional stability polyolefin It relates to a system composite resin composition.

Ethylene-propylene copolymer, ethylene-α-olefin copolymer

Description

Polyolefin-based composite resins {A composition of polyolefin-based complex resin}             

The present invention relates to a polyolefin composite resin composition, and more particularly, it is composed of a crystalline ethylene-propylene copolymer, an ethylene-α-olefin copolymer, and an inorganic reinforcing material having different ethylene content and melt index, respectively. Excellent impact resistance and heat resistance, while maintaining all these characteristics, especially the fluidity is extremely improved, excellent injection moldability, small shrinkage rate after injection molding, small coefficient of linear expansion and heat sag (heat sag) due to heat dimensional stability polyolefin It relates to a system composite resin composition.

Thermoplastic resins, in particular, polyethylene and polypropylene, which are polyolefin resins, have a low specific gravity, lower price than other resins, and have excellent 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, these polyolefin resins are difficult to apply in fields requiring special functions because of their limitation in physical properties. In order to overcome these disadvantages, by blending the two resins or adding mineral fillers, polyolefin-based composite resins with new functions that have not been provided before can be manufactured and applied to various fields that were not applicable to existing polyolefin-based resins. have. Particularly, the polyolefin resin composition which expresses the required physical properties by using polypropylene, which is a kind of polyolefin resin as a base material, and adding an ethylene-α-olefin copolymer or elastomer as an impact reinforcing material or an inorganic filler as a rigid reinforcing material is used for automobiles. It can be widely used for parts and parts. As such, many methods for improving various physical and thermal properties by changing the types of polypropylene resins, various types of impact reinforcing materials, and rigid reinforcing materials have been proposed, and many parts 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 using a polymer as a base material. At this time, it is important to select the type, property, size and content of the resin, filler or reinforcing material 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, the resin itself Processability, reproducibility, etc. can be maintained as is, and it is necessary to appropriately select the processing equipment and processing conditions so as to improve the property properties by the filler. In addition, additives such as heat stabilizers and weathering stabilizers are used to prevent the resin from deforming and aging due to the deformation and aging of the resin in high temperature and high pressure atmosphere in the extruder, or to express properties that are particularly needed after molding. Doing so is also an important variable in determining the properties of a composite resin. In addition, there is an interface between components between raw materials of different properties such as polymer base materials, fillers, and additives, and the properties of composite resins depend on the size of the interface adhesive at this interface. Attention should be paid to setting processing conditions.

Resin mainly used in the manufacture of interior and exterior parts and electronic components of the automobile, acrylonitrile-butadiene-styrene copolymer, blend of polycarbonate / acrylonitrile-butadiene-styrene copolymer, polycarbonate / polybutylene Terephthalate blends, polyamides, polyurethanes and the like. However, in the case of polyamide among these resins, it is difficult to be replaced by polyolefin composite resin due to the large difference in mechanical and thermal properties compared to polyolefin composite resin. However, the remaining resins except polyamide can be replaced with polyolefin composite resins in terms of weight reduction, cost reduction and recycling of automobiles, and are being replaced in many parts.

In order for the polyolefin-based composite resin to replace the resins, physical properties such as high rigidity, high impact resistance, high heat resistance, dimensional stability, and scratch resistance should be excellent.

In addition, since the thickness of parts and the like tend to be thinner according to the light weight of the automobile and the light weight of the parts, the moldability should be extremely excellent, and the molding time of the 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, a polyolefin composite resin composition which satisfies the above-described physical properties as a whole has not been developed yet.

Polyolefin-based composite resin compositions for automobile parts, in particular for molding large parts such as bumper fascia and instrument panel, have been developed in many ways, among which low shrinkage / low expansion coefficient The foot of the material is a big part. As the raw material for automobile parts, the most representative property is the rigidity of the raw material, which is expressed by flexural modulus and surface hardness, and is closely related to other physical properties such as tensile strength, elongation, impact strength, density, heat deformation temperature, and coefficient of linear expansion. have. Bumper fascia and instrument panels have a large surface area compared to relatively thin thicknesses and the molded article may bend or sag if there is not enough raw material.

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, the assembly of 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 due to heat 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 be intended to reduce the coefficient of linear expansion and to improve the flexural modulus. However, since the impact strength at low temperatures is lowered, the content of the filler must be appropriately 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 dimensional stability at the time of coating, and the need for less post deformation after molding.

As a method for producing a polyolefin composite resin composition used for molding automotive parts, an ethylene-propylene copolymer having a melt resin of 8 to 30 g / 10 min, a melt index of 0.1 to 7 g / 10 min and an ethylene content of 10 to 25 weight Process for producing high impact composite resin using% ethylene-propylene copolymer rubber, granular inorganic filler having an average particle size of 2 µm or less and 3 to 20 wt% of fragmentary inorganic filler having an average particle size of 5 µm or less [Japan Patent application Nos. 59-047252, Hei 5-179081, Hei 1-129052] have been disclosed, but there is a problem in the molding of large injection moldings because there is a limit to the improvement of injection molding.

In the present invention, in order to improve the above problems, the balance of impact resistance, stiffness and heat resistance, such as impact resistance, stiffness and heat resistance by balancing the ethylene ethylene propylene copolymer, the ethylene-α-olefin copolymer and inorganic reinforcing materials, each having a different content of ethylene It is possible to achieve a high price competitiveness by significantly reducing the content of expensive ethylene-α-olefin copolymer rubber, and excellent appearance of the molded product after injection molding, and in particular, the molding shrinkage and the coefficient of linear expansion are lowered to assemble the molded product with the vehicle body. Polycarbonate / acrylonitrile-butadiene, which is widely used in the molding of automotive interior parts by improving the stability of the molding and molding itself, minimizing post-deformation after painting and molding, and maximizing the ease of designing molds for molding products. -Polyolefin resin that can replace styrene copolymer alloy The purpose is to provide a composition.

The present invention contains 40 to 50% by weight of ethylene and 50 to 60% by weight of propylene, and 50 to 80 crystalline ethylene-propylene copolymer having a melt index of 10 to 30 g / 10 min (230 ° C., 2.16 kg). Weight percent; 20 to 50% by weight of propylene, 20 to 30% by weight of ethylene-propylene copolymer rubber or octene having a melt index of 0.1 to 5 g / 10 min (230 ° C., 2.16 kg) and 0.1 to 5 g 5-15 wt% of an ethylene-α-olefin copolymer selected from ethylene ° C. octene copolymer rubbers having a melt index of 10 min (230 ° C., 2.16 kg); And it is characterized by the polyolefin composite resin composition containing 15-30 weight% of calcium meta-silicates.

The present invention will be described in more detail as follows.

The polyolefin-based composite resin composition of the present invention is composed of crystalline ethylene-propylene copolymer, ethylene-α-olefin copolymer rubber, calcium-meta-silicate and additives, but the crystalline ethylene-propylene copolymer has an ethylene content of 40 Ethylene-α-olepene copolymer rubber is made of propylene or octene as α-olefin, and calcium-meta- as inorganic reinforcing material, and melt index is 10 to 30 g / 10min (230 ° C, 2.16 kg). As it is composed of silicate-based urastonite, there is a difference as compared with the conventional polyolefin-based composite resin to minimize the deterioration of the tearing property of the material such as impact resistance by the addition of inorganic reinforcing material, and thus the basic characteristics such as impact resistance, rigidity and heat resistance It is possible to balance the physical properties, significantly reduce the content of expensive ethylene-α-olefin copolymer rubber, excellent price competitiveness, injection properties The appearance of molded products 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 body and the dimensional stability of the molded product itself, and to minimize post deformation after coating and molding, and furthermore, to mold the product. By maximizing the design ease of use, the polycarbonate / acrylonitrile-butadiene-styrene copolymer alloy, which is widely used for molding automotive interior parts, can be replaced.

When described in more detail according to the component containing the polyolefin-based composite resin composition of the present invention as follows.

The crystalline ethylene-propylene copolymer is polymerized under a combined catalyst of titanium trichloride and alkyl aluminum compounds, generally called a Ziegler-Natta type catalyst, or by a titanium compound, a magnesium compound, or the like. Such crystalline ethylene-propylene copolymer is preferably 40 to 50% by weight of ethylene and 50 to 60% by weight of propylene, and preferably has a melt index of 10 to 30 g / 10 min (230 ° C., 2.16 kg). The crystalline ethylene-propylene copolymer is a resin in which a large amount of ethylene-propylene rubber is directly produced in the reactor by injecting an excessive amount of gaseous ethylene into the reactor in the production process of the ethylene-propylene copolymer. This resin is produced by directly producing a large amount of ethylene-propylene rubber in the reactor, and the ethylene-propylene rubber is dispersed in the crystalline polypropylene matrix with a uniform particle size, and the propylene component present in excess in the formed ethylene-propylene rubber is Excellent compatibility with polypropylene as a matrix, it is possible to improve the interfacial adhesion, impact strength and the like.

Therefore, the use of crystalline ethylene-propylene copolymer can significantly reduce the amount of additionally attached ethylene-α-olefin copolymer rubber for impact resistance, unlike in the case of general composite resin compositions. It is possible to manufacture, and to reduce the deviation between the lot of the product during production, it is possible to manufacture a product having uniform properties and performance.

This copolymer 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, and gel permeation chromatography. ) And the weight average molecular weight is 170,000 to 245,000, the number average molecular weight is 37,000 to 48,000.

Such crystalline ethylene-propylene copolymer uses 50 to 80% by weight based on the total resin composition. If the content is less than 50% by weight, the melt index of the resin composition is drastically lowered, so that the molding processability is lowered. If the content exceeds 80% by weight, the physical properties of the impact strength are lowered. At this time, the ethylene-propylene copolymer is an important melt index, if the melt index is less than 10g / 10min (230 ℃, 2.16 kg) molding processability is lowered, if it exceeds 30g / 10min (230 ℃, 2.16 kg) molding Processability is increased but physical properties are lowered. In addition, when the content of the ethylene-propylene rubber contained in the ethylene-propylene copolymer is out of the above range, there is a problem in that moldability is lowered and physical properties are weakened.

In the present invention, the ethylene-α-olefin copolymer rubber mainly contained for impact reinforcement is polymerized using a Ziegler-Natta type catalyst, in particular, a vanadium-based or chromium-based catalyst. In the ethylene-α-olefin copolymer rubber, α-olefin may be selected from 1-propylene, 1-butene, 1-hexene, and 1-octene, and preferably 1-propylene or 1-octene is used. . In the present invention, the ethylene-α-olefin copolymer rubber has a propylene content of 20 to 50% by weight and an ethylene-propylene copolymer rubber or octene having a melt index of 0.1 to 5 g / 10 min (230 ° C., 2.16 kg). It is 30 weight% and the thing chosen from the ethylene-octene copolymer rubber whose melt index is 0.1-15 g / 10min (230 degreeC, 2.16 kg) is used. Among the ethylene-α-olefin copolymer rubbers, ethylene-propylene copolymer rubbers are those having a propylene content of 20 to 50 wt% and a melt index of 0.1 to 5 g / 10 min (230 ° C., 2.16 kg). At this time, the pattern viscosity of ethylene-propylene copolymer rubber is 19-85ML _{1 + 4} (100 degreeC), and specific gravity is 0.86 g / cm <3>. In addition, in the present invention, ethylene-octene copolymer rubber may be used as another type of ethylene-α-olefin copolymer rubber for impact reinforcement. The content of octene, which is a co-monomer, is 20 to 30% by weight and a melt index. Is 0.1-15 g / 10min (230 degreeC, 2.16 kg), and the ethylene-octene copolymer rubber whose pattern viscosity is 19-50ML _{1 + 4} (121 degreeC) can be used. The ethylene-α-olefin copolymer rubber is contained in 5 to 15% by weight. If the content is less than 5% by weight, the impact strength of the resin composition decreases, and when the content exceeds 15% by weight, the impact resistance increases but the rigidity decreases. And moldability is reduced.

In the present invention, as the inorganic reinforcing material added for stiffening reinforcement, acicular calcium-meth-silicate-based ulastonite is used. It is preferable to use the ulastonite having an aspect ratio of 10 to 19 and an average diameter of the particles of 5 to 25 µm. It is preferable to contain 15 to 30% by weight of such urastonite. If the content is less than 15% by weight, the rigidity reinforcing effect does not appear much higher than that of conventional talc, and when it exceeds 30% by weight, the rigidity reinforcement effect is remarkably. However, the impact strength decreases and the moldability decreases.

In the present invention, additives commonly added in addition to the components described above may be used. Such additives may be added with an appropriate amount of coupling agents, antioxidants, long-term heat stabilizers, ultraviolet stabilizers, processing lubricants, carbon black, and the like. . If necessary, an antistatic agent, a nucleating agent, or the like can also be used. Coupling materials use 0.01 to 3% by weight of amino silane-based or amino titanium-based coupling materials to increase the adhesion strength between inorganic reinforcing materials and crystalline ethylene-propylene copolymers, and antioxidants and long-term heat stabilizers are resins that may occur during processing. In order to prevent the thermal decomposition of the primary and secondary is added, the primary antioxidant is added 0.05 ~ 0.52% by weight of phenolic antioxidant, the secondary antioxidant is 0.05 ~ 0.5% by weight of phosphorus or amine antioxidant Add. The UV stabilizer is added in the range of 0.05 to 0.5% by weight of a halogen-based UV stabilizer in order to reinforce the weather resistance and to prevent the decomposition of the resin due to the ultraviolet rays during outdoor exposure. In addition, carbon black is used in an amount of 0.5 to 2.0% by weight, and a processing lubricant is added in an amount of 0.05 to 0.5% by weight in order to enhance color development and weather resistance.

The resin composition of the present invention as described above is added to a Henschel mixer, a ribbon blender, a V-blender, etc. to mix the raw materials or to each raw material at a ratio determined by different raw material feeders. Is mixed directly into the processing machine. Processing machines include single screw extruders, twin screw extruders, or twin screw extruders, kneader mixers, Benbury mixers, in which parts of the extruder can be used as feed ports in addition to a single feed port, depending on the nature of the raw material and the final composition. such as a banbery mixer. The resin composition is introduced into a processing apparatus to melt and then pelletized.

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. Bumper fascia and instrument panel are manufactured by changing the amount, processing temperature, etc. and performing it under the optimum processing conditions.

Automotive parts such as bumper fascia or instrument panel manufactured using the polyolefin-based composite resin composition of the present invention as described above is excellent in mechanical rigidity, impact resistance and heat resistance, and maintains all these characteristics, especially fluidity It has the effect of excellent injection moldability, small shrinkage ratio after injection molding, small coefficient of linear expansion and heat sag due to heat, and excellent dimensional stability.

Although this invention is demonstrated in detail based on an Example, this invention is not limited to an Example.

Examples 1-7

Following the composition and content shown in Table 1a, the ethylene-propylene copolymer, the ethylene-α-olefin copolymer rubber, and the additives were mixed in advance using a timber mixer, which was twin screw extruder (Leistrz, Germany) The feed was fed to the first feeder, and the filler was melt blended to the second feeder.

At this time, the temperature of the extruder was set to 200 ℃ and the extrusion amount was set to the production amount of 100 kg per hour.

Comparative Examples 1 to 4

In the same manner as in Example 1, but a composite resin was prepared in the composition and content shown in Table 1b.

Experimental Example

Constant for the blend resin (PC / ABS) of the polycarbonate / acrylonitrile-butadiene-styrene copolymer widely used for molding the composite resins prepared in Examples 1 to 7 and Comparative Examples 1 to 4 and automobile interior parts. After the process of removing water and volatiles, injection or compressed specimens were manufactured to measure mechanical and thermal properties in accordance with the American Standard (ASTM) .If necessary, self-standards were established to measure the physical properties of the composition and the results are shown in Table 1a. And Table 1b.

The physical properties of the specimens were mainly by injection molding, and the injection specimens were used by Korea Venus Injection Machine (Model IDE90EN), and the cylinder temperature and mold temperature were fixed at 220 ℃ and 60 ℃, respectively. Was fixed and used in the region where physical properties can be expressed well. Injection specimens for measuring the physical properties were measured after leaving for 48 hours at 23 ℃, 50% relative humidity (RH) after injection.

Physical property measurement conditions are as follows.

(1) 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 were measured by the method specified in ASTM D638 (typel, cross-head speed = 50 mm / min).

(3) Flexural strength and flexural modulus were measured by the method specified in ASTM D790 (cross-head speed = 30 mm / min).

(4) Impact strength (impact strength) was measured at room temperature and low temperature (-30 ℃) according to ASTM D256. At this time, the weight of the rotary weight is 5 pounds.

(5) Heat deflection temperature: measured by the method specified in ASTM D648. At this time, the load is 4.16 kg.

(6) Mold shrinkage: 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 to 80 ° C by the method specified in ASTM D696.

(8) Heat sag: Before and after holding a specimen of 110 (L) × 20 (W) × 3 (H) mm in parallel with the floor in the longitudinal direction, and holding it in an oven at 120 ° C for 1 hour. The strain value was measured.

In Table 1a and Table 1b,

A1 is a crystalline ethylene-propylene copolymer having a melt index of 15.6 g / 10 min, containing 49.3 wt% of ethylene and a weight average molecular weight of 200,000.

A2 is a crystalline ethylene-propylene copolymer having a melt index of 20 g / 10min, 48.8% by weight of ethylene, and a weight average molecular weight of 180,000.

A3 is a crystalline ethylene-propylene copolymer having a melt index of 22 g / 10min, 47% by weight of ethylene, and a weight average molecular weight of 175,000.

B1 is an ethylene-α-olefin copolymer rubber having a melt index of 3.2 g / 10min and 27% by weight of propylene.

B2 is an ethylene-α-olefin copolymer rubber containing a melt index of 0.6 g / 10min and 43% by weight of propylene.

C1 is an ethylene-α-olephine copolymer rubber containing a melt index of 0.7 g / 10 min and 28 wt% octene.

C2 is an ethylene-α-olefin copolymer rubber having a melt index of 13 g / 10min and 28% by weight of octene.

Talc has a flat surface with an average diameter of 3 μm and an aspect ratio of 10.

Woollastonite is needle-shaped, has an average diameter of 8 µm and an aspect ratio of 17.

As described above, the polyolefin-based composite resin of the present invention can balance the basic physical properties such as impact resistance, stiffness and heat resistance, significantly reducing the content of expensive ethylene-α-olefin copolymer rubber, and having excellent price competitiveness, and 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 post deformation after coating and molding, and furthermore, to mold the product. By maximizing the design ease of use, it is possible to replace the polycarbonate / acrylonitrile-butadiene-styrene copolymer blend which is widely used in the molding of automotive interior parts.

Claims (4)

40 to 50% by weight of ethylene and 50 to 60% by weight of propylene, and 50 to 80% by weight of crystalline ethylene-propylene copolymer having a melt index of 10 to 30 g / 10 min (230 ° C., 2.16 kg); ; 20 to 50% by weight of propylene, 20 to 30% by weight of ethylene-propylene copolymer rubber or octene having a melt index of 0.1 to 5 g / 10 min (230 ° C., 2.16 kg) and 0.1 to 5 g 5-15 wt% of an ethylene-α-olefin copolymer selected from ethylene ° C. octene copolymer rubbers having a melt index of 10 min (230 ° C., 2.16 kg); And, A polyolefin-based composite resin composition, characterized in that it comprises 15 to 30% by weight of calcium-meth-silicate. The polyolefin-based composite resin composition according to claim 1, wherein the calcium-meta-silicate is needle-shaped ulastonite having an aspect ratio of 10 to 19 and an average diameter of particles of 5 to 25 µm. According to claim 1, wherein the composite resin composition is 0.05 to 0.5% by weight processing lubricant, 0.05 to 0.52% by weight phenol-based primary antioxidant, 0.05 to 0.5% by weight phosphorus or amine secondary antioxidant, 0.5 to 2.0 carbon black A polyolefin-based composite resin composition, characterized in that a weight%, 0.05 to 0.5% by weight of a halogen UV stabilizer, 0.05 to 3% by weight of an amino silane-based or amino titanium-based coupling material. Automotive instrument panel and interior plastic parts, characterized in that molded in the composition of claim 1.