JPH0689249B2 - 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 blended with a polyamide resin has also been proposed in order to improve the vibration damping performance under high temperature use conditions (see Japanese Patent Application Laid-Open No. 61-36357). 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).
10 ° to 30 ° C from the glass transition temperature (Tg) observed in C)
Exists in a high area. For example, nylon 6, nylon 66,
Linear aliphatic nylon such as Nylon 12, Nylon 11 and Nylon 610 has Tg of around 40 ° to 60 ° C and vibration damping performance of 60 ° to
It reaches a maximum around 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 et
Aromatic nylon such as amorphous nylon that is a copolymer with one or more of c) 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) 5 to 90% by weight of aliphatic nylon resin (b) 5 to 90% by weight of xylylenediamine type nylon resin.
And (c) a nylon resin composition containing 5 to 90% by weight of an aromatic non-crystalline nylon as an essential component.

The present invention will be described in detail below.

Examples of the above-mentioned (a) aliphatic nylon resin include nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 69, and the like, and further nylon 6 / nylon 66. It is also possible to use a mixture or copolymer of two or more aliphatic nylon resins such as nylon 6, nylon 6 / nylon 11 and nylon 66 / nylon 610. The molecular weight and viscosity of these nylon resins 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 linear dibasic acid include adipic acid, sebacic acid, suberic acid,
Examples thereof include azelaic acid and dodecanedioic acid.

The aromatic amorphous nylon (c) is a dicarboxylic acid containing a diamine selected from an alicyclic diamine or a mixture of an alicyclic diamine and a linear aliphatic diamine, and terephthalic acid and / or isophthalic acid as main components. With acid,
A nylon resin obtained by a polycondensation reaction of the diamine and the dicarboxylic acid in a substantially equimolar ratio,
It satisfies the following conditions (1) to (4). Its composition and manufacturing method are known in the art (see, for example, JP-A-58-17155 and JP-A-63-57668).

(1) It has an amide group (-NHCO) in the molecular chain.

(2) Glass transition temperature (Tg) is 100 ℃ or higher (3) Crystal fusion heat measured by differential scanning calorimeter (DSC) is less than 1 cal / polymer (4) Temperature range where complex elastic modulus is 10 N / mm ₂ or less Is Tg + 5
Within 0 ° C, the resin composition of the present invention is prepared by mixing pellets of each component, powder, etc. at a predetermined ratio with a tumbler type blender, a Hensiel mixer, a ribbon mixer, etc.,
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 an extruder is used, one or two of the components (a), (b) and (c) described above are fed in the form of pellets or powder or in a molten state during mixing. You may. 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, electric / mechanical parts, and particularly to automobile engines because the molded product has high vibration damping performance and excellent mechanical properties. Products in which noise is generated in a room due to vibration, such as a cylinder head cover, a gear cover, an oil pan, and the like, can be mentioned as preferred examples of use.

Cylinder head covers, gear covers, and other parts around the engine are required to have high rigidity and heat resistance in addition to damping performance, so glass fiber, mica, wollastonite, talc, carbon fiber, and other fillers should be used as materials. It is preferable to reinforce and use.

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 compounding ingredients shown in the table were mixed with a tumbler type blender for 5 minutes, and the resulting mixture was 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 is clear from the above description, the polyamide resin composition according to the present invention has a vibration-damping performance of the molded product, particularly 10
Excellent vibration damping performance under high temperature conditions of 0-120 ℃,
In addition, it is remarkably excellent in mechanical strength.

Claims (1)

[Claims] 1. (a) 5-90 wt% aliphatic nylon resin (b) 5-90 wt% xylylenediamine nylon resin
And (c) a polyamide resin composition containing 5 to 90% by weight of an aromatic non-crystalline nylon as an essential component.