JPH0645750B2 - 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 technology]

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. For the purpose of reducing noise, it is used as a molding material for automobile parts, particularly engine peripheral parts such as cylinder head covers and gear cases.

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, the nylon resin materials conventionally used for the above-mentioned automobile parts have insufficient vibration damping performance of the molded parts, or even if they have vibration damping performance, 80 ° C to 12 ° C.
There was a technical problem to be solved because the vibration damping performance in a high practical temperature range of about 0 ° 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, and by blending a specific polyamide resin in a specific ratio,
It has been found that a polyamide resin composition having properties that meet various requirements can be obtained.

[Disclosure of Invention]

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

The present invention provides a novel resin composition suitable for such purpose, namely (a) nylon 6 resin 5 to 90% by weight (b) aromatic diamine type nylon resin 5 to 90% by weight and (c) nylon 66 resin 5 to 90%. The present invention provides a polyamide resin composition characterized by containing wt% as an essential component.

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 aromatic diamine-based nylon resin (b) 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.

The resin composition of the present invention, by a conventional method, mixed pellets of each component, powder and the like at a predetermined ratio with a tumbler type blender, a Henschel mixer, a ribbon mixer and the like,
It can be obtained by melt mixing using an ordinary kneader such as a single-screw extruder, a twin-screw extruder, a kneader, or a Banbury mixer. When using an extruder, the above,
One or two of the components (a), (b) and (c) may be supplied in the form of pellets or powder or in a molten state during the mixing. 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.

In addition to damping performance, high rigidity and heat resistance are required for engine peripheral parts such as cylinder head covers and gear covers, so glass fibers, mica, wollastonite, talc, carbon fiber, etc. should be used as materials. It is preferable to reinforce with a filler.

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

[Sample preparation, measurement method]

In each of the examples and the comparative examples, the ingredients shown in the table were mixed for 5 minutes with a tumbler type blender, and the resulting mixture was mixed with L / L.
D = 27, melted and kneaded into pellets with a 30 mm counter-rotating twin-screw extruder. After drying the pellet at 100 ° C. for 5 hours, a test piece was formed by melt pressing and used as a sample. Before the measurement, it was annealed in vacuum at 100 ° C. for 8 hours.

・ 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.

-Tensile strength, tensile elongation at break Sample shape: JIS No. 3 dumbbell thickness 0.5 mm Measurement conditions: Crosshead speed 50 mm / min, 23 ± 3 ° C atmosphere, marked line spacing 20 mm The results obtained 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.

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

Claims (1)

[Claims] 1. A composition comprising (a) nylon 6 resin 5 to 90% by weight (b) aromatic diamine type nylon resin 5 to 90% by weight and (c) nylon 66 resin 5 to 90% by weight as essential components. A characteristic polyamide resin composition.