JPH0441706B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder head cover for an automobile made of resin that has characteristics such as heat resistance, rigidity, toughness, and road antifreeze resistance.

Recently, there has been a noticeable trend in the automobile industry to replace conventional metal parts with resin for purposes such as weight reduction, rust prevention, and sound insulation to improve fuel efficiency. Among them, polyamide resin has excellent heat resistance, oil resistance, moldability, rigidity, and toughness, so it is used in automobile underhood parts such as cooling fans, radiator tank tops and bases, cylinder head covers, etc. Applications to various functional parts such as oil pans, gears, valves, brake piping, fuel piping tubes, and exhaust gas system parts are attracting attention.

Among polyamide resins, nylon 11 and nylon 12
High-grade polyamides, such as these, have good toughness, dimensional stability, and chemical resistance, and are also excellent in resistance to road antifreeze agents such as calcium chloride and magnesium chloride, so they are used as materials for the underhood parts of automobiles mentioned above. Although it has attracted great interest as a material and is already being used in some special functional parts, the reality is that the expansion of its use is limited due to its lack of rigidity as a metal substitute material. On the other hand, polyamides with a relatively high concentration of amide groups such as nylon 6 and nylon 66 are heat resistant,
Due to its high rigidity and low cost, it has a considerable track record of use as a material for automotive underhood parts.
It is not necessarily a satisfactory material because it has disadvantages such as high moisture absorption, poor dimensional stability, and cracks caused by attack by road antifreeze agents such as calcium chloride, magnesium chloride, and zinc chloride. .

Therefore, as the demand for automotive underhood resin parts increases, the emergence of underhood parts made of polyamide materials that have heat resistance, rigidity, toughness, dimensional stability, road antifreeze resistance, etc. is eagerly awaited. The current situation is that

Therefore, the present inventors investigated polyamide-based underhood parts for automobiles that almost simultaneously satisfy the above-mentioned required properties, and found that a mixture of polyamide nylon 66 and high-grade polyamides such as nylon 11 and nylon 12 was further developed. The inventors have discovered that underhood parts for automobiles made of a mixture containing an inorganic reinforcing material are extremely excellent, and have thus arrived at the present invention.

That is, the polyamide of the present invention (A) having hexamethylene adipamide units as the main structural unit: 5 to 95
Weight% and (B) Equimolar salts of aliphatic amino acids having 11 or 12 carbon atoms, lactams, and aliphatic diamines having 6 to 12 carbon atoms and aliphatic dicarboxylic acids having 6 to 12 carbon atoms (with the exception of hexamethylene diammonium adipate) A mixture of 5 to 95% by weight of polyamide obtained by melt polymerizing at least one selected from
An object of the present invention is to provide an automobile cylinder head cover formed by molding a compound containing 30 to 100 parts by weight of (C) inorganic reinforcing material per 100 parts by weight.

The polyamide used as component (A) in the present invention is polyhexamethylene adipamide (nylon
66) and copolyamides and mixed polyamides containing this as the main component. Representative examples of the polyamide as component (B) used in the present invention include 11-aminoundecanoic acid, 12-aminododecanoic acid, ω-laurolactam, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-/2,4,4-trimethylhexamethylene diamine and adipic acid,
A polyamide obtained by melt polymerizing at least one selected from equimolar salts of azelaic acid, sebacic acid, and dodecanedioic acid (excluding equimolar salts of hexamethylene diamine and adipic acid), such as nylon 11. , Nylon 12, Nylon 6/9, Nylon 6/10, Nylon 6/12, Nylon 11/
6, Nylon 11/12, Nylon 12/6, Nylon
12/10, nylon 12/12, or copolymers containing these as main components. In particular, in the present invention, nylon 6.9, nylon 6.10, and nylon 6.12 are preferably used. The degree of polymerization of the polyamide used here is not particularly limited, and polyamides having a relative viscosity generally within the range of 2.0 to 6.0 can be arbitrarily selected.

Examples of the inorganic reinforcing material used in the present invention include glass fiber, asbestos fiber, carbon fiber, wollastenite, talc, calcium carbonate, magnesium oxide, alumina, mica, spherical glass, and potassium titanate whiskers.

The resin cylinder head cover for automobiles of the present invention contains component (A) 5 to 95% by weight of polyamide, preferably
30 to 90% by weight and (B) component polyamide 5 to 95% by weight,
Preferably, the material is formed by adding 30 to 100 parts by weight of the inorganic reinforcing material (C) to 100 parts by weight of a 1 to 70% by weight mixture. The mixing amount of (A) component polyamide, that is, nylon 66 in all polyamides is 5
If it is less than % by weight, it is not possible to obtain a cylinder head cover with high rigidity, so it is not preferable.
If the amount of component (A) polyamide used exceeds 95% by weight, the resulting cylinder head cover's road antifreeze properties will be noticeably deteriorated, making it impractical. On the other hand, the amount of inorganic reinforcement used is all polyamide 100
If it exceeds 100 parts by weight, it is not preferable because the toughness decreases and the product becomes brittle, impairing its function as an automobile cylinder head cover.

The method of mixing the polyamide and the inorganic reinforcing material is not particularly limited, and a commonly known method can be employed. In other words, at least two types of polyamide pellets, powders, strips, etc. and inorganic reinforcing material are uniformly mixed using a high-speed stirrer, and then melt-kneaded using an extruder with sufficient kneading capacity, or dry blend injection or extrusion molding. Either method can be adopted. Of course, it includes inorganic reinforcement (A)
A method such as mixing the component polyamide and the component (B) polyamide and various modifications of this method can also be employed.

The resin automobile cylinder head cover of the present invention is generally molded by known molding methods for thermoplastic resins such as injection molding, extrusion molding, blow molding, and vacuum molding, but injection molding is particularly preferred. The molded parts thus obtained can also be subjected to secondary processing such as painting, vapor deposition, and adhesion.

In addition, other components such as pigments, dyes, heat resistant agents, antioxidants, weathering agents, lubricants, crystal nucleating agents, etc. may be added to the automobile cylinder head cover of the present invention as long as they do not impair its moldability and physical properties. can do.

The present invention will be explained in more detail with reference to Examples below.

The physical properties of the cylinder head covers and corresponding test pieces described in the Examples and Comparative Examples were measured by the methods described below.

(1) Relative viscosity: JIS K6810 (2) Water absorption: ASTM D570 (3) Tensile properties: ASTM D638 (4) Bending properties: ASTM D790 (5) Izot impact strength: ASTM D256 (6) Heat distortion temperature: ASTM D648 (7) Road antifreeze resistance: Injected molded products at 80℃
After treating with hot water for 24 hours, leave it at 100℃ or rotate it with the gear open, and heat the
% calcium chloride aqueous solution in the form of water droplets was treated as one cycle, and the number of cycles until cracks appeared in the molded product was measured.

Example 1 Nylon 6.10:40% by weight having a relative viscosity of 2.7 was added to nylon 66:60% by weight having a relative viscosity of 2.8, and to this 100 parts by weight, further 15 parts by weight of chopped strand glass fiber and wollastenite were added. Add 25 parts by weight of
The mixture was melted and kneaded using a large-diameter extruder, and then pelletized.

After vacuum drying the pellets obtained here,
An automobile cylinder head cover and a JIS No. 1 dumbbell piece were molded using an injection molding machine at a cylinder temperature of 280°C and a mold temperature of 80°C. The results of measuring the physical properties of the obtained test piece when completely dry are as follows.
The molded product was found to be well-balanced in terms of rigidity, toughness, and heat resistance.

Tensile strength 1200Kg/cm ² Bending strength 1900Kg/cm ² Flexural modulus 62000Kg/cm ² Izot impact strength 7Kg・cm/cm Notch heat distortion temperature 210℃ Water absorption 0.9% Also, the molded cylinder head cover is made of the above-mentioned calcium chloride resistant material. When a cycle test was carried out, no cracks appeared at all up to 10 cycles, confirming that the product had excellent road antifreeze properties.

Comparative Example 1 When the calcium chloride resistance of a cylinder head cover obtained by molding the mixture of nylon 66 and glass fiber/wollastenite used in Example 1 under the same conditions as in Example 1 was evaluated, it was found that only one cycle was required. Cracks appeared on the entire surface of the molded product.

Comparative Example 2 The physical properties of a test piece obtained by molding the mixture of nylon 6/10 and glass fiber/wollastenite used in Example 1 under the same conditions as in Example 1 are as follows. As a metal substitute material for head covers, it has not been found to have practical value in terms of rigidity.

Tensile strength 1000Kg/ ^cm2 Bending strength 1500Kg/ ^cm2 Bending modulus 55000Kg/ ^cm2

Claims (1)

[Claims] 1 (A) Polyamide whose main constituent unit is hexamethylene adipamide unit: 5 to 95% by weight and (B)
Aliphatic amino acids with 11 or 12 carbon atoms, lactams, aliphatic diamines with 6 to 12 carbon atoms, and aliphatic diamines with 6 to 12 carbon atoms
Equimolar salts of 12 aliphatic dicarboxylic acids (excluding hexamethylene diammonium adipate)
An automobile obtained by molding a compound containing 30 to 100 parts by weight of an inorganic reinforcement (C) to 100 parts by weight of a mixture of 5 to 95% by weight of polyamide obtained by melt polymerizing at least one selected from the following. cylinder head cover.