JPH0753861A - Resin composition for automobile cooling system parts - Google Patents

Abstract

PURPOSE:To provide the composition comprising a polyamide having a specific relative viscosity, a specified modified polypropylene, and glass fibers, having both high mechanical strength and flowability, excellent in calcium chloride resistance and antifreezine solution resistance, and optimal for a melted core- molding method. CONSTITUTION:The composition comprises (A) 50-90wt.% of a polyamide resin having a relative viscosity of 2.2-3.0 in 97%, sulfuric acid, (B) 10-40wt.% of a modified polypropylene modified with a carboxylic acid or its derivative in a modification amount of 0.05-5wt.% and having a melt-flow rate of 20-60g/10min at 190 deg.C, the sum of the components A and B being 100 pts.wt., and (C) 10-100 pts.wt. of glass fibers. (D) A polyhydric alcohol such as HO-(C2H4 O-)nH or HO-(CH2)n-OH (n is 1-6) is preferably simultaneously used in an amount of 0.1-2.5 pts.wt. per 100 pts.wt. of the resin component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for automobile cooling system parts which has excellent resistance to calcium chloride, antifreeze and long-life coolant and has high fluidity.

[0002]

2. Description of the Related Art Generally, polyamide resin has excellent properties such as mechanical strength and heat resistance.
Further, by reinforcing it with glass fiber, it becomes a material having higher strength and higher heat resistance. Therefore, glass fiber reinforced polyamide is used in a wide range of industrial applications, and especially for automobile applications, its applications are expanding by replacing metal parts for the purpose of improving performance such as weight reduction, cost reduction, sound insulation and heat insulation. There is. However, it is known that the polyamide resin is deteriorated by antifreeze, long-life coolant and calcium chloride used as an antifreezing agent, and its mechanical properties are deteriorated.

Further, automobile parts, especially parts for cooling systems, have complicated shapes, and in order to obtain molded articles having such complicated shapes, resin molding materials having high fluidity are required.
On the other hand, because of the high strength required for the product, if it is reinforced with glass fiber or the like as described above, there is a problem that the fluidity generally decreases. When the fluidity is low, the glass floats on the surface, the surface smoothness and appearance are deteriorated, and molding may be impossible due to insufficient fluidity of the resin depending on the shape. Therefore, if you try to cope with molding conditions such as increasing the injection rate of the injection molding machine or increasing the injection pressure, the mold life will be shortened, and problems such as ejection pin and core damage will often occur. There is a limit to what can be dealt with.

Further, as a method for molding a component having a complicated shape, a melted core molding method may be used. In this case, however, if the resin has low fluidity, the core will be deformed and the desired shape cannot be obtained. The problem occurs. Therefore, there is a demand for a high-strength resin molding material having excellent fluidity and excellent resistance to calcium chloride, antifreeze and long-life coolant.

As a method for increasing the resistance of polyamide resin to calcium chloride, antifreeze and long life coolant, a method of adding polypropylene resin having excellent resistance to calcium chloride, antifreeze and long life coolant is known.
It has been proposed to use compositions consisting of glass fibers in automotive parts. However, polyamide, polypropylene and glass fiber compositions having both high mechanical strength and high fluidity are not known.

For example, Japanese Patent Publication No. 61-26939 discloses a radiator tank made of a composition containing a polyamide resin, an acid-modified polypropylene and a fibrous reinforcing agent. However, when the polyamide resin and the acid-modified polypropylene are mixed, the polyamide and the modified polypropylene react with each other to form a high-molecular weight graft copolymer, which increases the melt viscosity. In particular, since the modified polypropylene has a high molecular weight as the modified polypropylene, it has a particularly high melt viscosity, and it is difficult to obtain a molded product having a complicated shape. There are drawbacks such as not being obtained. In addition, Japanese Patent Publication 1-198
Japanese Patent Publication No. 133 discloses an automobile molded article composed of polyamide, modified polyolefin, polyolefin and glass fiber. In this case, since an unmodified polyolefin is used in combination, the viscosity increase due to the reaction between the polyamide and the modified polyolefin can be suppressed, but the compatibility between the polyamide and the polyolefin is poor, the mechanical strength is low, and the variation is large. There is.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of such a background, the present inventors have blended a polyamide having a specific relative viscosity with a modified polypropylene having a specific modification amount and MFR and a glass fiber. It has excellent mechanical strength, heat resistance, calcium chloride resistance, antifreeze resistance, long life coolant resistance, high fluidity, and can be used for injection molded parts with complicated shapes. The optimum molding material for automobile cooling system parts using the molten core molding method, which is one of the molding methods for products with a shape,
I found what I could get.

That is, the present invention relates to [A] polyamide resins 60 to 90 having a relative viscosity of 2.2 to 3.0 in 98% sulfuric acid.
100% by weight of a resin component consisting of 10% by weight and [B] a modified polypropylene modified with a carboxylic acid or a carboxylic acid derivative, and 40% by weight, and [C] a glass fiber 10-1.
The modified polypropylene as the component [B] has a modification amount of 0.05 to 5% by weight and a melt flow rate at 190 ° C. of 20 to 60 g / 10 minutes. Resin component 1 comprising a resin composition for cooling system parts and a polyhydric alcohol represented by the general formula (I) or (II) consisting of a polyamide resin and modified polypropylene
The present invention relates to a resin composition for automobile cooling system parts, which is used in an amount of 0.1 to 2.5 parts by weight relative to 00 parts by weight. _{HO- (C 2 H 4 O-)} n H (I) HO- (CH 2) n -OH (II) ( wherein _n represents 1 to 6)

In the present invention, the vehicle cooling system parts are parts of an engine cooling system, various pipes of a water circulation system, pump parts and the like, and specifically, water inlet pipes, water outlet pipes, water pump housings, radiator tanks. And a heater core around the heat exchanger for heating.

Polyamides used in the present invention include polyamides obtained from lactams such as ε-caprolactam, ε-laurolactam and 2-pyrrolidone, 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid. Polyamide obtained from aminocarboxylic acid,
Polyamides obtained by polycondensation of diamines such as tetramethylenediamine, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, metaxylylenediamine, and dicarboxylic acids such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, and These copolymers, a mixture, etc. are mentioned. Specifically, nylon 4, nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 612, nylon 6 /
66, nylon 6/610, nylon 6/12, nylon 66 / 6T, nylon 6T / 6I (T is a terephthalic acid component, I is an isophthalic acid component) and the like.
Of these, nylon 6, nylon 66, and nylon 66 / 6T, which have excellent rigidity and heat resistance, are preferable. The relative viscosity of the polyamide used in 98% sulfuric acid is 2.2.
3.0 is preferable, and 2.3 to 2.8 is particularly preferable. When the relative viscosity is less than 2.2, the mechanical strength is poor and 3.0
If it exceeds, the fluidity decreases.

As the modified polypropylene used in the present invention, polypropylene obtained by grafting an unsaturated carboxylic acid derivative on polypropylene is preferably used. As the raw material polypropylene, a propylene homopolymer, a random or block copolymer with ethylene, a mixture thereof or the like can be used. Examples of unsaturated carboxylic acid derivatives for grafting include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid and metal salts thereof such as sodium salts, calcium salts, magnesium salts and zinc salts, maleic anhydride, itaconic anhydride and the like. Examples of the acid anhydride include maleic anhydride and itaconic anhydride. The grafting method is not particularly limited, and a known method can be used. For example, polypropylene and unsaturated carboxylic acid derivatives, t-butylperoxybenzoate, cyclohexanone peroxide, 2,5-dimethyl-2,5-
Di (benzoylperoxy) hexane, t-butylperoxyacetate, methyl ethyl ketone peroxide,
A method in which a reaction initiator such as dicumyl peroxide or 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is melt-mixed may be used.

The modified amount of the modified polypropylene is preferably 0.05 to 5 wt% with respect to the polypropylene, and is 0.1.
~ 3.0 wt% is particularly preferred. If the amount of modification is less than 0.05%, the effect of modification is small and the compatibility of polyamide and polypropylene is poor, resulting in a decrease in mechanical strength. Sex deteriorates. The MFR of modified polypropylene at 190 ° C is 20-
60 g / 10 min is preferable, and 25-45 g / 10 min is particularly preferable. If the MFR is less than 20 g / 10 minutes, the fluidity is poor, and if it exceeds 60 g / 10 minutes, the mechanical strength, particularly the rigidity is poor.

As the glass fibers used in the present invention, those used for ordinary resin reinforcement can be used. Examples thereof include glass roving, glass chop strands, glass milled fiber, glass powder and the like. Further, it is preferable that the surface of these glass fibers is treated with a silane compound such as aminosilane and then treated with a sizing agent such as an acrylic, urethane or epoxy type.

The resin composition for automobile cooling system parts of the present invention is obtained by melt-kneading the above-mentioned polyamide, modified polypropylene and glass fiber. The ratio of polyamide to modified polypropylene is 60-90 polyamide.
%, Modified polypropylene amount 10 to 40% by weight is preferable. When the polyamide ratio is less than 60% by weight, mechanical strength and heat resistance are poor, and when it exceeds 90% by weight, resistance to calcium chloride, antifreeze and long life coolant is improved. Less effective. The amount of glass fiber used is 10 to 1 with respect to 100 parts by weight of the total of polyamide and modified polypropylene.
00 parts by weight is preferable, when the glass fiber is less than 10 parts by weight, the rigidity is low, and when it exceeds 100 parts by weight, the fluidity is poor.
The order of kneading is to knead polyamide, modified polypropylene and glass fiber at the same time, mix polyamide and modified polypropylene and then knead glass fiber, knead glass fiber and polyamide or modified polypropylene and then add another resin component. Any of the kneading methods may be used. A method in which an extruder having a feed port in the nozzle part in addition to the normal feed port, polyamide, modified polypropylene is fed from the normal feed port and glass fiber is fed from the feed port of the nozzle part is particularly preferably used. .

Polyhydric alcohols may be used in the present invention to further improve the fluidity. The polyhydric alcohol used in the present invention is a polyhydric alcohol represented by the general formula (I) or (II), and specifically, polyethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol and mixtures thereof are mentioned. Of these, 1,5-pentanediol is particularly preferable. _{HO- (C 2 H 4 O-)} n H (I) HO- (CH 2) n -OH (II) ( wherein _n represents 1 to 6)

The polyhydric alcohol used in the present invention is preferably used in an amount of 0.1 to 2.5 parts by weight, and preferably 0.1 to 2.5 parts by weight, based on 100 parts by weight of the total amount of polyamide and modified polypropylene.
Particularly preferred is 5 to 1.2 parts by weight. If the amount of polyhydric alcohol used is less than 0.1 parts by weight, the effect of improving fluidity is small, and if it exceeds 2.5 parts by weight, bleeding occurs on the surface of the molded product.
The surface property deteriorates. As the method of adding the polyhydric alcohol, a method of simultaneously kneading polyamide, modified polypropylene, and glass fiber when melt-kneading, or a method of mixing polyamide, modified polypropylene, and glass fiber into a melt-pelletized mixture is used.

In the resin composition for exterior parts of the present invention, conventionally known additives such as antioxidants, ultraviolet absorbers, lubricants, pigments, antistatic agents, flame retardants, plasticizers, nucleating agents, dyes, etc. , A modifier can be added.

[0018]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0019]

[Example 1] 70% by weight of nylon 66 (UBE nylon 2015B manufactured by Ube Industries, Ltd.) having a relative viscosity of 2.5 and maleic anhydride modified polypropylene (modified amount 0.4%, MF
R30 g / min) 30% by weight was mixed in a pellet state using a blender. 2 with a feed port on the cylinder
Using a shaft extruder, a resin pellet mixture was fed from a normal feed port, and glass fibers (using an acrylic sizing agent) were fed from a feed port of a cylinder part. The ratio of the resin component to the glass fiber was 55 parts by weight of glass fiber with respect to 100 parts by weight of the resin component. Table 1 shows the physical properties and fluidity of the obtained composition.

[0020]

Examples 2 to 4 In Example 2, 1,5-pentanediol as a polyhydric alcohol was blended with the composition pellet of Example 1 and the physical properties and fluidity were evaluated in the same manner as in Example 1. In Example 3, the modified polypropylene was modified with itaconic anhydride (modification amount 0.6 wt%, MFR 45 g / 10 min).
Instead, the ratio of polyamide / modified polypropylene / glass fiber was changed, and in Example 4, nylon 66 / 6T copolymer (66 / 6T = 50/50 weight ratio) was used as the polyamide component, and the polyhydric alcohol was 1. Example 2 was repeated except that 6-hexanediol was used.

[0021]

Comparative Examples 1 to 3 In Comparative Example 1, only modified polyamide and glass fiber were kneaded without adding modified polypropylene. In Comparative Example 2, a modified polypropylene having a high viscosity (modification amount 0.2%, MFR 15 g / 10 min) was used, and Comparative Example 3
Then, the same procedure as in Example 1 was carried out except that an unmodified one (MFR 20 g / 10 min) was used.

[0022]

[Table 1]

[0023]

EFFECTS OF THE INVENTION According to the present invention, it has both mechanical strength and fluidity, which have been difficult to achieve with a composition of polyamide, modified polypropylene and glass fiber, and has calcium chloride resistance,
It is possible to easily obtain a resin composition for automobile cooling system parts, which is excellent in antifreeze resistance and long-life coolant resistance and which is most suitable for the production of parts having a complicated shape, particularly the melt core molding method.

Claims (2)

[Claims] 1. [A] Relative viscosity in 98% sulfuric acid 2.2.
Resin component 100 comprising 60 to 90% by weight of 3.0 polyamide resin and 10 to 40% by weight of [B] carboxylic acid or carboxylic acid derivative-modified polypropylene
The modified polypropylene as the component [B] is composed of 10 parts by weight and 10 to 100 parts by weight of glass fiber [C].
A resin composition for automobile cooling system parts, which has a melt flow rate at 190 ° C of 20 to 60 g / 10 minutes. 2. A polyhydric alcohol represented by the general formula (I) or (II) is used in an amount of 0.1 to 2.5 parts by weight per 100 parts by weight of a resin component consisting of a polyamide resin and modified polypropylene. 1. The resin composition for automobile cooling system parts according to 1. _{HO- (C 2 H 4 O-)} n H (I) HO- (CH 2) n -OH (II) ( wherein _n represents 1 to 6)