JPH08157657A - Resin composition for automotive antifreezing liquid system part and its molded part - Google Patents

Abstract

PURPOSE: To obtain the subject composition comprising PP, a polyphenylene ether and an inorganic filler in a specific ratio, and exhibiting excellent mechanical strength, creep resistance, heat resistance, rigidity, dimensional stability and contact durability with an antifreezing liquid at high temperatures. CONSTITUTION: This composition comprises (A) 50-90 pts.wt. of PP preferably having a density of 0.9080-0.9340g/cm<3> (especially 0.9085-0.9150g/cm<3> ), a melt flow rate of 0.5-300g/10min (especially 5.0-100g/10min), and a functional group concentration of >=0.01wt.%, (B) 10-50 pts.wt. of a polyphenylene ether comprising a (co)polymer of the formula (Q<1> , Q<2> are a halogen, a primary or secondary alkyl, etc.; (m) is >=10), and (C) 15-200 pts.wt. of an inorganic filler preferably comprising glass fibers treated with a surface-treating agent such as a silane or titanate surface treating agent, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition suitable for automobile antifreeze system parts and molded parts thereof. These resin compositions and molded parts thereof have excellent mechanical strength, creep resistance, and excellent durability even in contact with an antifreeze solution at high temperatures.

[0002]

2. Description of the Related Art In the field of automobiles, resin parts are being used for metal parts because of their merits such as weight reduction, clothes characteristics, and productivity improvement. That is, not only the outer panels and exterior parts represented by bumpers, but also the metal parts in the engine room are being resinized. An automobile antifreeze system part can be mentioned as a typical part in the engine room. These parts are specifically radiator tanks,
Water pump housings, water valves, etc., which are usually parts that come into contact with antifreeze liquid for a long time at high temperature.

Conventionally, these have been mainly made of aluminum, but due to the above reasons, they have been made into resins, and at present, glass fiber reinforced polyamide is mainly used. This utilizes the excellent mechanical strength, heat resistance and oil resistance of glass fiber reinforced polyamide. However, polyamide has a drawback that its strength is lowered by being in contact with an antifreeze solution at high temperature for a long time, and is not necessarily optimum for a part requiring severe reliability. Also,
Polypropylene, which is widely used as an automobile part, has a great effect of reducing the weight and has no reduction in strength due to an antifreeze solution, but has a problem in practical use in terms of heat resistance and rigidity. Further, polypropylene is not sufficient in dimensional stability, warpage occurs in a molded product, and there is a problem in flatness of a joint surface.
As described above, no satisfactory material has been found as a material for the antifreeze liquid system parts mounted in the automobile engine room.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention have excellent mechanical strength, heat resistance rigidity and dimensional stability, and maintain high mechanical strength even when they are in contact with an antifreeze liquid for a long time at high temperature. It is an object of the present invention to provide a material having excellent creep resistance and suitable for an automobile antifreeze liquid system component, and an automobile antifreeze liquid system component obtained by molding the material.

[0005]

That is, according to the present invention, the following components (a), (b) and (c) are blended in the following amount with respect to 100 parts by weight in total of the components (a) and (b). A resin composition for automotive antifreeze system parts, characterized by containing in a ratio of (a) polypropylene 50 to 90 parts by weight (b) polyphenylene ether 10 to 50 parts by weight (c) inorganic filler 15 to 200 parts by weight.

Particularly, polypropylene has a density of 0.9080.
The resin composition for automobile antifreeze system parts is polypropylene having a weight ratio of 0.9340 g / cm ³ . Further, each is an automobile antifreeze system component formed by molding the above resin composition. Hereinafter, the present invention will be described in detail.

(1) Polypropylene (a) The polypropylene (a) used in the present invention is a polymer containing propylene as a main constituent monomer, specifically, a propylene homopolymer or propylene as a main component. And ethylene, butene-1, hexene-1,
It is a copolymer with an α-olefin such as heptene-1 or 4-methylpentene-1. These copolymers may be random copolymers or block copolymers, but block copolymers are more preferable. Among them, crystalline polypropylene is preferable, and propylene homopolymer and propylene-
Ethylene block copolymers are especially preferred, and propylene homopolymers are most preferred.

The melt flow rate of these polypropylenes (a) (hereinafter referred to as "MFR". JIS K721.
0; 230 ℃, 2.16kg load) 0.5-300g / 10
It is preferably minutes, more preferably 1.0 to 20
0 g / 10 minutes, particularly preferably 5.0-100 g / 10 minutes. If the MFR is less than 0.5 g / 10 minutes, the moldability is insufficient,
If it exceeds 300 g / 10 minutes, the mechanical strength is unsatisfactory.

The polypropylene (a) is used for the purpose of improving the affinity with the inorganic filler, such as carboxyl group, acid anhydride group, epoxy group, amino group, carboxylic acid ester group, amide group, sulfonic acid group and sulfone group. Acid ester group,
It is preferable to use polypropylene introduced with a functional group such as a hydroxyl group. The polypropylene into which these functional groups are introduced has a functional group concentration of 0.
It is preferably used in an amount of 01% by weight or more, and more preferably 0.03% by weight or more.

The polypropylene (a) used in the present invention has a density of 0.908 measured according to JIS K7112.
It is preferably 0 to 0.9340 g / cm ³ , more preferably 0.9082 to 0.9250 g / cm ³ , and particularly preferably 0.9085 to 0.9150 g / cm ³ .
If the density is less than 0.9080 g / cm ³ , the creep resistance is unsatisfactory, and if it exceeds 0.9340 g / cm ³ , the production is difficult.

The polypropylene having the above-mentioned density can be produced by a method other than the method of directly obtaining by polymerization, by increasing the density by adding a nucleating agent to the polypropylene having a density lower than the above, and adjusting the density within the above range.

Any nucleating agent may be used as long as it improves the crystallinity of polypropylene. Representative examples include metal salts of aromatic carboxylic acids, sorbitol derivatives, organic phosphates, organic nucleating agents such as aromatic amide compounds, and inorganic nucleating agents such as talc. It is not particularly limited to these.

(2) Polyphenylene ether (b) The polyphenylene ether (b) used in the present invention has the following general formula (I).

[0014]

Embedded image

(Wherein Q ¹ represents a halogen atom, a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a hydrocarbonoxy group or a halohydrocarbonoxy group, and Q ² represents a hydrogen atom. , A halogen atom, a primary or secondary alkyl group, an aryl group, a haloalkyl group, a hydrocarbon oxy group or a halohydrocarbon oxy group, and m represents an integer of 10 or more). It is a polymer or a copolymer.

Preferable examples of the primary alkyl group for Q ¹ and Q ² include methyl, ethyl, n-propyl, n-butyl and n.
-Amyl, isoamyl, 2-methylbutyl, n-hexyl, 2,3-dimethylbutyl, 2-, 3- or 4-
Methyl pentyl or heptyl. Suitable examples of secondary alkyl groups are isopropyl, sec-butyl or 1-ethylpropyl. In many cases, Q ¹ is an alkyl group or a phenyl group, especially an alkyl group having 1 to 4 carbon atoms,
Q ² is a hydrogen atom.

Suitable polyphenylene ether homopolymers are, for example, those composed of 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include the above units and 2,3,6-trimethyl-1,
It is a random copolymer composed of a combination with a 4-phenylene ether unit. Many suitable homopolymers or random copolymers are described in the patents and literature. For example,
Also suitable are polyphenylene ethers containing molecular moieties that improve properties such as molecular weight, melt viscosity and / or impact strength.

The polyphenylene ether (b) used here preferably has an intrinsic viscosity of 0.2 to 0.8 dl / g at 30 ° C. measured in chloroform. The intrinsic viscosity is more preferably 0.2 to 0.7 dl / g, and particularly preferably 0.25 to 0.6 dl / g.
If the intrinsic viscosity is less than 0.2 dl / g, the impact resistance of the composition will be insufficient, and if it exceeds 0.8 dl / g, the moldability will be unsatisfactory.

Further, the resin composition of the present invention may contain styrene resins such as polystyrene, rubber-reinforced polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer and the like. The blending amount of these is preferably 30% by weight or less when the total amount of polyphenylene ether and styrene resin is 100% by weight.

(3) Inorganic Filler (c) As the inorganic filler (c) used in the present invention, various known ones can be used. For example,
Glass fiber, carbon fiber, potassium titanate whiskers,
Fibrous fillers such as metal fibers and wollastonite; talc,
Plate-shaped fillers such as mica and glass flakes; spherical fillers such as glass beads and glass balloons. It is also possible to use two or more of these in combination. Among these, the fibrous filler is most preferable from the viewpoint of the reinforcing effect, and the glass fiber is most preferable from the viewpoint of cost. When a fibrous filler is used, it is also preferable to use a plate-like filler together in order to suppress warpage of the molded product due to anisotropy. It is more preferable that these inorganic fillers are treated with a silane-based or titanate-based surface treatment agent in order to improve the affinity with the resin component.

(4) Additional components Further, the resin composition of the present invention may contain additional components other than the above. For example, impact resistance improvers such as elastomers, antioxidants, weather resistance improvers, nucleating agents, flame retardants, flame retardant aids such as anti-drip agents, lubricants, additives such as release agents, plasticizers, Flowability improvers, various colorants and their dispersants can be used as additional components.

In order to improve the compatibility between the polyphenylene ether and polypropylene, it is preferable to add a compatibilizer component. The compatibilizer used in the present invention may be any one as long as it improves the compatibility between the polyphenylene ether and polypropylene. Specific examples thereof include polyphenylene ether graft polypropylene, styrene graft polypropylene, aromatic alkenyl compound-conjugated diene block copolymer partially hydrogenated product, and the like. As such a compatibilizer component, in the market,
The styrene-grafted polypropylene is a product name of “VMX” from Mitsubishi Chemical Co., Ltd., and the aromatic alkenyl compound-conjugated diene block copolymer partial hydrogenation product is a product of “Clayton G” from Shell Chemical Co. They are sold under the trade name “Septon” by Kuraray Co., Ltd. and under the trade name “Tuftec” by Asahi Kasei Kogyo Co., Ltd., and are easily available. The compounding amount of these compatibilizers is preferably 0.1 to 40 parts by weight, more preferably 0.5 to 35 parts by weight, based on 100 parts by weight of the total of polyphenylene ether and polypropylene.
It is particularly preferably 1 to 30 parts by weight.

In the present invention, low density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-propylene rubber, ethylene-butene rubber, ethylene and vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, anhydrous An ethylene resin such as a copolymer of maleic acid can also be used. The blending amount of these is preferably 30% by weight or less when the total amount of polypropylene and ethylene resin is 100 parts by weight.

(5) Composition Ratio of Constituents The composition ratio of the components (a) to (c) in the resin composition for antifreeze system parts of the present invention is 100 parts by weight of the total of the components (a) and (b). It is as follows.

Component (a): 50 to 90 parts by weight, preferably 50 to 85 parts by weight, more preferably 55 to 80 parts by weight. If the amount of component (a) is less than 50 parts by weight, moldability will be insufficient, and if it exceeds 90 parts by weight, heat resistance will be unsatisfactory. Component (b): 10 to 50 parts by weight, preferably 15 to 50
Parts by weight, more preferably 20 to 45 parts by weight. If the amount of the component (b) is less than 10 parts by weight, heat resistance is insufficient, and if it exceeds 50 parts by weight, moldability is unsatisfactory. Component (c): 15 to 200 parts by weight, preferably 25 to 1
50 parts by weight, more preferably 35 to 120 parts by weight. If component (c) is less than 15 parts by weight, mechanical strength and heat resistance are unsatisfactory, and if it exceeds 200 parts by weight, moldability is insufficient.

(6) Method for producing composition and molding method As the method for obtaining the resin composition of the present invention, various known methods can be used, but the melt kneading method is the most general method. As the melt-kneader, a kneader generally used for thermoplastic resins can be applied. For example, a single-screw or multi-screw kneading extruder can be applied, rolls,
It may be a Banbury mixer or the like. The kneading temperature is usually 180 to 350 ° C.

The kneading may be carried out by blending all the components and then simultaneously kneading them, kneading them by using a blend prepared by preliminarily kneading some of the components, or by mixing some of them in the middle of the extruder cylinder. It has a feed port,
Examples include a method of sequentially feeding each component.

The molded article of the present invention can be molded by various molding methods generally used for thermoplastic resins, that is, injection molding, hollow molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding and the like. It can be molded by the method.

The use of the molded article of the present invention is automobile antifreeze system parts. The automobile antifreeze system parts here are
It is a component that comes into contact with an antifreeze solution containing ethylene glycol as the main component. Specific examples include a radiator tank, a water pump housing, a water valve, a water impeller, a radiator pipe, and a heater tank.

[0030]

EXAMPLES The present invention will be described more specifically with reference to the following examples.

Example 1 As polypropylene (a), a propylene homopolymer (manufactured by Mitsubishi Chemical Co., trade name: Mitsubishi Polypro MA2A, MF)
R: 25 g / 10 min, density: 0.9070 g / cm ³ , hereinafter "M
A2A ") 75 parts by weight, maleic anhydride grafted polypropylene (maleic anhydride content 0.8% by weight) 5
Parts by weight, as the polyphenylene ether (b), poly (2,6-dimethyl-1,4-phenylene ether)
(Nippon Polyether Co., intrinsic viscosity in chloroform at 30 ° C .: 0.44 dl / g), styrene-isoprene-styrene block copolymer hydrogenated product (Kuraray Co., trade name: Septon 2104) 10 parts by weight Was thoroughly mixed and stirred with a super mixer. Then, using a twin-screw extruder (TEX44, manufactured by Japan Steel Works, Ltd.), this was set at 230
Glass fiber (made by Asahi Fiber Glass Co., Ltd., diameter 10 μm) as an inorganic filler (c) from the feed port provided in the middle of the extruder cylinder while melting and kneading at a screw rotation speed of 250 rpm. Was fed so that the ratio was 110: 55, melt-kneaded to obtain a composition, and then pelletized.

Injection molding was carried out from the pellets of the above resin composition using an in-line screw type injection molding machine (manufactured by Japan Steel Works, mold clamping force 100T) at a cylinder temperature of 260 ° C and a mold cooling temperature of 80 ° C. , A test piece was prepared.

In the injection molding, a vacuum dryer was used immediately before the injection molding for 48 hours under the condition of 0.1 mmHg and 80 ° C. The injection-molded test piece was placed in a desiccator immediately after molding, allowed to stand at 23 ° C. for 4 to 6 days, and then evaluated by the method described below. The results are shown in Table 1.

(I) Flexural Modulus ISO R178-1974 Procedure 12 (JIS
According to K7203), using an Instron tester 23
It was measured at ° C. (Ii) High temperature flexural modulus retention rate ISO R178-1974 Procedure 12 (JIS
According to K7203), using an Instron tester 80
The measurement was performed at 0 ° C., and the retention rate for the bending elastic modulus at 23 ° C. was obtained.

(Iii) Izod impact test Measured at 23 ° C. according to JIS K7110 notched Izod impact test method. (Iv) Heat distortion temperature Using an HDT tester (manufactured by Toyo Seiki Seisakusho), JI
It was evaluated according to SK7207 under a load of 18.6 kg.

(V) Antifreeze resistance A test piece (JIS K7113 tensile test piece No. 1 dumbbell) was immersed in a 50% aqueous solution of an antifreeze solution, heated to 120 ° C., and the tensile strength after 1,000 hours was measured. The retention rate with respect to the tensile strength of immersion was determined. (Vi) Dimensional stability 100 × 60 × 2 using a mold having a film gate
mm square plate is injection molded and the flow direction (MD) of this molded product
Also, the molding shrinkage in the vertical direction (TD) was measured, and the difference (TD-MD) was defined as the dimensional stability. (vii) Creep resistance JIS bending test piece (width 10 mm, thickness 4 mm, fulcrum spacing 64 m
Bending stress of 200 kg / cm ² was continuously applied to m) at 120 ° C., and the time until breakage was measured.

Examples 2 and 3 and Comparative Examples 1 to 4 Melt kneading, molding and evaluation were carried out in the same manner as in Example 1 except that the composition ratio of each component was changed to the ratio shown in Table 1, and the results were obtained. The results are shown in Table 1. Comparative Examples 2 and 3 could not be molded and could not be evaluated.

Example 4 The resin components were thoroughly mixed and stirred with a super mixer in the proportions shown in Table 1. Then, using a twin-screw extruder (manufactured by Japan Steel Works, TEX44), while melt-kneading the mixture at a set temperature of 230 ° C. and a screw rotation speed of 250 rpm, an inorganic material was fed from a feed port provided in the middle of the extruder cylinder. Glass fiber (made by Asahi Fiber Glass Co., Ltd., diameter: 10 μm) and mica (made by Kuraray Co., Ltd.) are fed as a filler (c) so that the ratio of the resin component, the glass fiber and the mica is 110: 35: 20, and melt-kneaded The resulting composition was pelletized, molded and evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 5 Polyamide 66 (manufactured by BASF, trade name: A3W) 10
0 parts by weight of twin-screw extruder (TEX44 manufactured by Japan Steel Works)
Set temperature 280 ℃, screw rotation speed 250
While melt-kneading at rpm, glass fiber (made by Asahi Fiber Glass Co., Ltd., diameter: 10 μm) was fed from a feed port provided in the middle of the extruder so that the ratio of the resin component and the glass fiber was 100: 50. After melt-kneading to obtain a composition, it was pelletized.

Injection molding was carried out from the pellets of the above resin composition using an in-line screw type injection molding machine (manufactured by Japan Steel Works, mold clamping force 100T) at a cylinder temperature of 290 ° C. and a mold cooling temperature of 80 ° C. Table 1 shows the results of the test pieces prepared and evaluated in the same manner as in Example 1.

[0041]

[Table 1]

Example 5 Propylene homopolymer as polypropylene (a) (manufactured by Mitsubishi Chemical Co., trade name: MA3U, MFR: 15 g / 10 minutes,
Density: 0.9085 g / cm ³ , written as “MA3U”)
75 parts by weight, maleic anhydride grafted polypropylene (maleic anhydride content 0.8% by weight) 5 parts by weight, poly (2,6-dimethyl-1,4-phenylene ether) as polyphenylene ether (b) (Nippon Polyether Co., Ltd.) Intrinsic viscosity measured in chloroform at 30 ° C .: 0.
44 dl / g) 20 parts by weight, styrene-grafted polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: VMX DN65X) 10
Part by weight was thoroughly mixed and stirred with a super mixer. Then, this is a twin-screw extruder (TEX44 manufactured by Japan Steel Works, Ltd.)
Using, set temperature 230 ℃, screw speed 250
While melt-kneading at rpm, glass fiber (made by Asahi Fiber Glass Co., Ltd., diameter: 10 μm) was used as an inorganic filler (c) through a feed port provided in the middle of the extruder cylinder so that the weight ratio of the resin component to the glass fiber was 110. : 55, melt-kneaded to form a composition, and then pelletized. Table 2 shows the results of molding and evaluation of the obtained pellets in the same manner as in Example 1.

Example 6 The composition ratio of each component was changed to the ratio shown in Table 2, except that MA2A was used as the polypropylene (a) and 0.1% by weight of NA11 manufactured by Adeka Argus was blended as the nucleating agent with respect to the polypropylene. Is melt-kneaded in the same manner as in Example 1,
Molding and evaluation were performed, and the results are shown in Table 2. The density of the polypropylene compounded with the nucleating agent is separately melt-kneaded at a cylinder temperature of 230 ° C. using a 30 mm single-screw extruder, and an injection molding machine having a mold clamping force of 100 T and a cylinder temperature of 220. Injection molding was performed at a temperature of 40 ° C. and a mold temperature of 40 ° C., and the obtained test piece was used.

Example 7 The results of molding and evaluation in the same manner as in Example 1 are shown in Table 2 except that the composition ratio of each component was changed to the ratio shown in Table 2.

Example 8 The resin components were thoroughly mixed and agitated with a super mixer in the proportions shown in Table 2. Then, using a twin-screw extruder (TEX44 manufactured by Nippon Steel Co., Ltd.), while melt-kneading at a set temperature of 230 ° C. and a screw rotation speed of 250 rpm, an inorganic filler is fed from a feed port provided in the middle of the extruder cylinder. As (c), glass fiber (made by Asahi Fiber Glass Co., Ltd., diameter: 10 μm) and mica (made by Kuraray Co., Ltd.) were fed so that the weight ratio of the resin component, glass fiber and mica was 110: 35: 20, and melt-kneaded. The resulting composition was pelletized, molded in the same manner as in Example 6, and evaluated. The results are shown in Table 2.

Comparative Example 6 The results of molding and evaluation in the same manner as in Example 1 are shown in Table 2 except that the composition ratio of each component was changed to the ratio shown in Table 2.

Example 9 The composition ratio of each component was changed to the ratio shown in Table 2, and a propylene homopolymer as polypropylene (a) (manufactured by Mitsubishi Chemical Corporation,
Product name: MH6, MFR: 1.2g / 10 minutes, density: 0.9
Molding and evaluation were carried out in the same manner as in Example 1 except that 055 g / cm ³ ) was used, and the results are shown in Table 2.

Example 10 Molding and evaluation were carried out in the same manner as in Example 1 except that the composition ratio of each component was changed to the ratio shown in Table 2, and the results are shown in Table 2.

Example 11 The composition ratio of each component was changed to the ratio shown in Table 2, and a propylene-ethylene block copolymer (trade name: BC8, MFR: 1.8 g / 10, manufactured by Mitsubishi Chemical Co., Ltd.) was used as polypropylene (a).
Min, density 0.9070 g / cm ³ , written as “BC8”)
Molding and evaluation were carried out in the same manner as in Example 1 except that was used, and the results are shown in Table 2.

[0050]

[Table 2]

[0051]

The resin composition for automobile antifreeze system parts of the present invention has excellent characteristics such as high mechanical strength, heat resistance rigidity and dimensional stability, and good antifreeze resistance and high temperature creep resistance. Further, the automobile antifreeze system parts obtained by molding the same sufficiently meet the recent demand for higher performance of resin parts for automobiles.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yukio Uchiyama 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. Yokkaichi Research Institute (72) Inventor Nobuyuki Hamano 3-chome 1-1 Hinodai, Hino-shi, Tokyo Hino Automobile Industry Co., Ltd. (72) Inventor Satoshi Kintsu 3-1-1 Hinodai, Hino City, Tokyo Hino Automobile Industry Co., Ltd.

Claims (3)

[Claims] 1. The following components (a), (b) and (c):
A resin composition for automobile antifreeze system parts, characterized by containing the following components in a mixing ratio of 100 parts by weight of the components (a) and (b) in total. (A) 50 to 90 parts by weight of polypropylene (b) 10 to 50 parts by weight of polyphenylene ether (c) 15 to 200 parts by weight of inorganic filler 2. The polypropylene has a density of 0.9080 to
The resin composition for automobile antifreeze system parts according to claim 1, which is 0.9340 g / cm ³ of polypropylene. 3. An automobile antifreeze system component formed by molding the resin composition according to claim 1 or 2.