JPH0645751B2 - Polyamide resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to automobile parts, particularly a cylinder head cover,
The present invention relates to a polyamide resin composition suitable as a material for an engine peripheral component such as a gear case that requires damping performance.

[Background Art] Nylon resin materials are lighter in weight than metal materials, and have various excellent performances in terms of vibration damping, rigidity, heat resistance, oil resistance, etc. In recent years, it has been used as a molding material for automobile parts, particularly engine peripheral parts such as a cylinder head cover and a gear case, for the purpose of weight reduction and noise reduction.

Generally, resin materials are superior to metal materials in damping performance of their parts, but from the viewpoint of noise reduction effect, solid propagating sound, that is, sound due to vibration of the parts themselves is reduced, but its specific gravity is small. Based on
To increase. Therefore, in order to obtain an effective noise reduction effect due to material conversion, it is required to reduce solid-borne sound that exceeds the increase in air-transmitted sound. That is, in other words, extremely high vibration damping performance is required.

From this point of view, conventionally, the nylon resin material used for the above-mentioned automobile parts has insufficient vibration damping performance of the molded parts, or even if the vibration damping performance is 80 ° C.
There was a technical problem to be solved because the vibration damping performance in the high practical temperature range of about 120 ° C was not sufficient.

A resin composition in which a tackifier resin is mixed with a polyamide resin has been proposed in order to improve the vibration damping performance under high-temperature use conditions (see Japanese Patent Laid-Open No. 61-36357), but the strength and rigidity of molded parts can be improved. There are problems to be solved in terms of points.

Generally, plastic materials have strong viscoelastic properties,
The damping performance is highest around the maximum temperature of the loss tangent (tan δ) of the mechanical dispersion based on the glass transition of the polymer material, which is usually the differential scanning calorimetry (DS).
From the glass transition temperature (Tg) observed in C) 10 ° to 30
Exists in a region higher by ℃. For example, nylon 6 and nylon 6
Linear aliphatic nylons such as 6, nylon 12, nylon 11, nylon 610, etc., have maximum Tg at 40 ° to 60 ° C and vibration damping performance at around 60 ° to 80 ° C. As other nylon resins, crystalline metaxylylenediamine resin (MXD nylon) having an aromatic ring in the molecular chain, one or more diamines and dicarboxylic acid (terephthalic acid, isophthalic acid).
etc.) of aromatic nylon such as amorphous nylon which is a copolymer with one or more of etc.) has a Tg of 120 ° C or higher and its vibration damping performance is maximized in a high temperature region of 130 ° C or higher. .

The present inventors have conducted various studies for the purpose of improving the vibration damping property and mechanical properties of the polyamide resin material, as a result, a specific polyamide resin was blended at a specific ratio, and further, an inorganic filler was added thereto. It has been found that a polyamide resin composition having properties that meet various requirements can be obtained by blending in a specific ratio.

[Disclosure of Invention]

It is an object of the present invention to provide a new reinforced polyamide resin composition for obtaining a molded part having remarkably excellent mechanical strength as well as improved vibration damping performance.

The present invention provides, as a novel resin composition suitable for such purpose, (a) nylon 6 resin 5 to 90% by weight (b) xylylenediamine type nylon resin 5 to 90% by weight.
And (c) 100 parts by weight of a mixture composed of 5 to 90% by weight of nylon 66 resin, and (d) 10 to 150 parts by weight of an inorganic filler are blended to provide a polyamide resin composition. Is.

The present invention will be described in detail below.

The above-mentioned (a) nylon 6 resin used in the composition of the present invention is a polyamide having 90 mol% or more of caprolactam units, and may contain other comonomer components such as ω-laurolactam. Good. The molecular weight and viscosity are not particularly limited, and those having a molecular weight range that allows molding under normal molding conditions are preferable.

The (x) xylylenediamine-based nylon resin is a crystalline nylon resin composed of xylylenediamine and an aliphatic straight-chain dibasic acid. The xylylenediamine is metaxylylenediamine or paraxylylenediamine. Alternatively, it is a mixture of these. Examples of the above aliphatic straight chain dibasic acid include adipic acid, sebacic acid, suberic acid, azelaic acid, dodecanedioic acid and the like.

As this resin, nylon MXD6 containing metaxylylenediamine and adipate as main constituents is particularly preferable.

The nylon 66 resin of (c) above is a polyamide having 90 mol% or more of hexamethylene adipamide units, and may contain other comonomer components such as ω-laurolactam. The molecular weight and viscosity are not particularly limited, and those having a molecular weight range that allows molding under normal molding conditions are preferable.

Examples of the inorganic filler of (d), glass fiber, mica, talc, wollastonite, barium sulfate, clay, calcium carbonate, carbon fiber, silicon carbide fiber, potassium whisker titanate, calcium sulfate whiskers, etc. In particular, glass fiber or a combination of glass fiber and mica has an extremely large reinforcing effect and is most suitable for the resin composition of the present invention.

The glass fiber referred to here is one that is used for a normal glass fiber reinforced resin, and its shape is not particularly limited, long fibers such as glass roving, chopped strands, short fibers such as milled fiber, and the like, Any shape can be used. It is particularly preferable that the glass fiber is surface-treated with a silane coupling agent, a titanate coupling agent, or the like.

The resin composition of the present invention, by a conventional method, (a), (b),
(c) A mixture of pellets, powders, etc. of each resin component in a predetermined ratio with a tumbler blender, a Henschel mixer, a ribbon mixer, etc. together with the inorganic filler of (d), a single-screw extruder, a twin-screw extruder. It can be obtained by melt-kneading using an ordinary kneading machine such as a kneader, a kneader, or a Banbury mixer. When an extruder is used, one or two of the resin blending components (a), (b) and (c) above may be mixed in pellets or powder or in a molten state during mixing. May be supplied. Various other modified methods can be used.

The resin composition of the present invention includes an antioxidant, an ultraviolet absorber, a lubricant, an antistatic agent, a nucleating agent, a release agent, a plasticizer, a pigment, and a flame retardant as long as the moldability and physical properties of the product are not impaired. , Extenders, inorganic fillers, fibrous reinforcing agents, other resin materials and the like can be added.

INDUSTRIAL APPLICABILITY The resin composition according to the present invention is applicable to automobile parts and electric / mechanical parts because the molded product has high vibration damping performance and excellent mechanical properties, and in particular, it is an engine for automobiles. Products in which noise is generated in the room due to vibration, such as a cylinder head cover, a gear cover, and an oil pan, may be mentioned as suitable examples of use.

Below, the Example regarding the resin composition which concerns on this invention is given with a comparative example.

[Sample preparation, measurement method]

Among the compounding components shown in the table for both the examples and the comparative examples, the resin compounding components except the inorganic filler were mixed for 5 minutes with a tumbler type blender, and the resulting mixture was L / D = 27, 30 mm.
The most downstream part of the screw of the counter-rotating twin-screw extruder (end)
Then, the inorganic filler was supplied in the middle of the screen, melted and kneaded, and then pelletized. This pellet was dried with hot air at 100 ° C. for 8 hours, and then a test piece having a predetermined shape was prepared by injection molding, which was used as a sample. Before measurement of physical properties, the sample should be kept in vacuum at 100 ℃ for 8 hours.
Annealed for a time.

・ Loss coefficient (Note: This is a measure of vibration damping performance) Sample shape: 150 mm × 150 mm, thickness 3 mm Measurement method: Measure the transfer function by shaking the center of the sample with 0.1 G in a constant temperature bath. The loss coefficient η was calculated from the next resonance point by the half-width method.

・ Flexural modulus: Compliant with ASTM D790 ・ Izod impact strength (with notch): Compliant with ASTM D256 ・ Heat deformation temperature: Compliant with ASTM D648 However, 18.6 kg / cm ² load The obtained results are shown in the table.

As described above, as apparent from the above, the polyamide resin composition according to the present invention has a vibration-damping performance of the molded article, particularly 80
It has excellent vibration damping performance under high temperature conditions of ~ 100 ° C.
In addition, it is remarkably excellent in mechanical strength and heat resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area C08L 77:06) (C08L 77/06 77:02)

Claims (1)

[Claims] (A) Nylon 6 resin 5 to 90% by weight (b) Xylylenediamine type nylon resin 5 to 90% by weight
And (c) 100 parts by weight of a mixture consisting of 5 to 90% by weight of nylon 66 resin, and (d) 10 to 150 parts by weight of an inorganic filler, which is a polyamide resin composition.