JPS6038434A - Fiber-reinforced high-impact polyamide resin wheel - Google Patents

Abstract

PURPOSE:The titled wheel particularly excellent in low-temperature impact resistance, etc., obtained by using a fiber-reinforced resin obtained by mixing a glass fiber having a specified mean diameter with a polyamide 6-based resin as a material for at least a rim part. CONSTITUTION:A fiber-reinforced resin is prepared by mixing 80-40pts.wt. (A) polyamide 6 or polyamide 6-based resin (e.g., a copolymer of polyamide 6 with polyamide 66) with (B) 20-60pts.wt. glass fiber having a mean diameter of 3- 8mu. The resulting fiber-reinforced resin is used as a material for at least a rim part to obtian the purpose fiber-reinforced high-impact polyamide resin wheel. This wheel can be suitably used for automobiles especially in a cold district. It is preferable that the glass fiber used is surface-treated beforehand with a silane coupling agent of good heat stability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide resin wheel reinforced with glass fibers and having excellent impact resistance, high rigidity and heat resistance, and particularly excellent drop ball impact strength at low temperatures.

Recently, there has been a growing demand for highly impact-resistant wheels for automobiles that can withstand large impact loads from the outside.Especially in the case of automobile wheels, as the automobile market expands, Naturally, low-temperature impact resistance in cold regions and winter impact resistance are now required.

Currently, resin materials are being researched and developed to replace metal materials as automobile wheel members, but they have not become widespread due to impact resistance and cost considerations. In addition, as a general-purpose automotive component, we have developed a high-strength, high-rigidity, and high-impact resin composition for structural materials among glass fiber-reinforced plastics made mainly of unsaturated polyester. A composition containing 5Q wt% or more of fiber (hereinafter referred to as H3MC) is well known. H3MC is widely used for automobile parts such as bumper beams due to its excellent impact resistance, etc. However, since these parts cannot be processed by injection molding, molded parts are mainly produced by press molding.

However, the press molding method has lower productivity and higher molding costs than the injection molding method, so it is difficult to use thermoplastic resin materials that can be injection molded and have physical properties comparable to H3MC molded products. Development is strongly requested.

Therefore, if we focus only on impact resistance, modification methods such as modifying with rubber or adding plasticizers to polyamide have been proposed as methods for making polyamide high impact. Although this method improves impact strength, it tends to cause a decrease in rigidity, and has the disadvantage that high-temperature rigidity or heat resistance is lower than that of H8MC, and the excellent properties of polyamide resin are impaired.

Moreover, in both methods, the low-temperature impact resistance rapidly decreases at temperatures below the glass transition point of the rubber or below the solidification point of the plasticizer, and for example, cracks or fractures easily occur due to the impact of a falling 500f steel ball. Although it has the following drawbacks and fully satisfies the practical performance of falling ball impact resistance at low temperatures, it has not been possible to obtain l.

Therefore, in view of the above-mentioned current situation, the present inventors have developed a polyamide resin that has high strength and high impact that can sufficiently resist H8MC, without sacrificing its excellent properties, strength and rigidity, and that is particularly effective against falling ball impact at low temperatures. As a result of intensive studies with the aim of further improving strength, we discovered that J
The inventors have discovered that the falling ball impact strength at low temperatures, as defined by S.S., is significantly improved, and can therefore be used satisfactorily for automobile wheels, leading to the development of the present invention.

That is, the present invention provides a wheel in which at least the rim portion is made of fiber-reinforced resin, in which polyamide 6 is added to the fiber-reinforced resin.
Or add 2 glass fibers with an average diameter of 3μ to 8μ to 80 to 40 parts by weight of polyamide resin containing this as the main component.
High rigidity and JI mixed at a ratio of 0 to 60 parts by weight
The main idea is a fiber-reinforced resin wheel using a resin composition that has significantly improved low-temperature falling ball impact strength of -30°C as specified in SK-7211.

Next, the composition used in the present invention will be specifically described in detail.

The hyliamide resin used in the present invention is polycaprolactam (polyamide 6) or a copolymer mainly composed of polycaprolactam (polyamide 6).
6. A polyamide 6/aliphatic polyamide copolymer having a copolymer composition in which an aliphatic polyamide such as polyamide 12, polyamide 610, polyamide 116, polyamide 11, or polyamide 12 does not exceed lQ wt% is preferred. . (〃/〃 means that it is a copolymer.) Zaraani polyamide 4M resin has a relative viscosity (relative viscosity measured by the method described below) in the range of 2.2 to 4.0. It is preferably 2.5 to 3.2, and if it is less than 22, the ball impact resistance will not improve, and if it exceeds 4.0, the moldability will deteriorate and it will be difficult to obtain a satisfactory molded product.

The glass fibers used in the present invention have an average diameter in the range of 3μ to 8μ, preferably 5 to 8μ, and range from long fiber types (glass rovings) to short fiber types (chopped strands and milled fibers). is used, preferably the latter type. The glass fibers used in the present invention are preferably surface-treated with a thermally stable silane coupling agent, particularly an aminosilane camping agent.

Even if the glass fiber diameter is reduced from the conventional glass fiber diameter of 13-14μ to 10μ, the falling ball impact strength improves slightly, but not significantly. Surprisingly, falling ball impact at low temperatures is significantly improved by mixing glass fibers with a fiber diameter of 8 microns or less into a specific polyamide resin to strengthen it.

Even if the glass fiber diameter is made even thinner than 3μ, the falling ball impact strength at low humidity is almost saturated; on the contrary, when mixed with polyamide resin, the glass fibers become smaller and more easily broken, and the fiber length becomes extremely short, resulting in a decrease in rigidity. This would deviate from the purpose of the present invention, which is to use a resin material with high strength and high rigidity equivalent to H8MC for the wheel.

The amount of glass fiber mixed in the polyamide resin is 20 to 60 parts by weight, based on 80 to 40 parts by weight of the polyamide resin.
Preferably, the amount is 70 to 55 parts by weight and 30 to 45 parts by weight. If it is less than 20 parts by weight, no improvement in ball impact resistance will be observed, and if it exceeds 60 parts by weight, moldability will be significantly reduced.

The method of mixing the polyamide resin and glass fiber is not particularly limited, and any commonly known method can be employed. For example, polyamide resin pellets, powder, strips, etc. and glass fibers are uniformly mixed in a known mixer, melt-kneaded in an extruder with sufficient kneading capacity, and then molded, or pre-extruded. Any method may be used, such as direct mixing in a molding machine without kneading into pellets using a machine or the like.

The resin composition used in the present invention may contain other ingredients, such as fillers, flame retardants, antistatic agents, stabilizers, pigments, mold release agents, nucleating agents, and plasticizers, as long as they do not impair falling ball impact strength and rigidity at low temperatures. Agents may also be added.

The composition used in the present invention thus obtained can be processed by injection molding,
It can be applied to known molding methods such as extrusion molding and blow molding. It is particularly preferably applied to injection molding applications.

The polyamide composition used in the present invention has high impact properties, especially its molded product has a falling ball impact strength of 40 to 9-c at -30°C.
m or more, which is superior to H8Mc. Also, the bending strength is 2,
It has a high strength of 000~/cr1 or more.

Below, the composition used in the present invention will be explained in further detail.

In addition, the measurement of the falling ball impact strength at low temperature for each composition example was based on the following JIS standard.

(1) Falling ball impact strength (JIS K7211-1976
) Flow rate 23°C ± 2°C and relative humidity 50 ± 5 before testing
% in 100. To prevent moisture absorption, a 91 mm x 3 mm thick disc molded product was sealed in a plastic bag and placed at -3
01: 3 hours in a low temperature chamber (manufactured by Tabai Seisakusho) with a constant Kv
Leave it alone. A 5362 steel ball with a diameter of 50 tah is dropped from various heights onto a cooled disc molded product held horizontally on a jig, and the fracture energy (50% fracture energy) when the steel ball breaks at 50% frequency is estimated. Ta. That is, the falling ball impact strength was calculated according to the following formula.

H: Complete failure height crn) h, Falling ball level spacing (crn) S Total number of two side deviations (ke) N: Number of samples at one level (ke) W: Steel ball weight (Kp) = 0.536 (K4) The relative viscosity referred to in the following Examples and Comparative Examples is a value measured at 25°C after dissolving Polymer 12 in 98% concentrated sulfuric acid 100-.

Composition Example 1 55 parts by weight of nylon 6 with a relative viscosity of 2.7 and 45 parts by weight of chopped strand short fiber glass fibers having a fiber diameter of 6.4μ and a fiber length of 3I+II++ treated with a silane compound were uniformly mixed using a mixer. A pellet for molding was obtained using a 65-diameter single-screw extruder at a cylinder temperature of 260°C.

Next, after vacuum drying this pellet, the cylinder temperature is 2.
60℃, injection pressure 00 Ky/l #l, mold temperature 90
Injection molding was carried out using an injection molding machine 5J-35B manufactured by Meiki Manufacturing Co., Ltd. at 100° C. to obtain a molded article for measuring mechanical strength and a molded article for measuring falling ball impact strength (100+++ mφ x 3 fermentation thickness).

The mechanical strength is shown in Table 1, and the measurement results of the falling ball impact strength at -30°C are shown in Table 2.

Composition Example 2 [A molded article for measurement was obtained in the same manner as in Example 1, except that chopped strand glass fibers with an I of 47.2μ and a fiber length of 3 were used.

The measurement results are shown in Tables 1 and 2.

Comparative Composition Example I H3MC Press Sea) (H3MC-H2O2) was obtained, and a test piece for measuring bending strength (12.5 mm width x 1
Disc molded products of 00 length x 3TMl thickness) and 100teφ x 3τ thickness were cut and subjected to physical property measurements. The measurement results are shown in Tables 1 and 2.

Comparative Composition Example 2 and Comparative Composition Example 3 Molded articles for measuring falling ball impact were prepared in the same manner as in Example 1, except that chopped strand glass fibers with a fiber diameter of 1.3μ and a fiber length of 10.5μ were used, 3I+0+1. I got it.

The measurement results are shown in Table 2.

From the above results, it can be seen that the combination of nylon 6 and reduced diameter glass fiber (8μ or less) has a remarkable improvement in falling ball impact strength at low temperatures, and even exceeds the strength of H8Mc.

Composition Example 3 Polyamide 6/Polyamide 66 (9) with a phase viscosity of 3.2
0/1.0%) copolymer; 30 parts by weight of silane-treated chopped strand short fiber glass fibers with a fiber diameter of 6.2 μ and a fiber length of 6 holes were added to 70 parts by weight using a mixer. The mixture was mixed uniformly using a 65 mm diameter single-screw extruder at a cylinder temperature of 280° C. to obtain pellets for molding.

Next, after vacuum drying this pellet, the foam-like injection molding machine 5
Using J-35B, injection molding was carried out at a cylinder temperature of 280°C, an injection pressure of 570 Kf/aA, and a mold temperature of 90°C.
×3 solution thickness) was obtained. The measurement results at ~30°C are shown in Table 3.

Composition Example 4 A molded article for measuring falling ball impact strength was obtained in the same manner as in Example 3 except that chopped strand short glass fibers having a taMu diameter of 5.2 μm and a fiber length of 6 fibers were used. The measurement results are shown in Table 3.

Comparative Composition Example 4 A molded article for measuring falling ball impact strength was obtained in the same manner as Composition Example 3 except that glass fibers with a fiber diameter of 13.5 μm and a fiber length of 3τ were used. The measurement results are shown in Table 3.

Table 1 Table 2 Table 3 Composition Example 5 Nylon 6/nylon 66 copolymer (9
015%) 55 parts by weight were treated with silane and the fiber diameter was 6.
45 parts by weight of chopped strand short glass fibers having a fiber length of 4 μm and a fiber length of 3 mm were uniformly mixed, and in the same manner as in Example 3, pellets for molding and molded products for strength measurement were obtained.

The falling ball impact strength at -30°C was 84 Ky-α.

The wheel of the present invention will be specifically explained in detail below.

FIG. 1 is a diagram illustrating a wheel 1 of the present invention cut radially from the center. The rim chamber disc portion 6 of the wheel 1 is integrally injection molded. Any of Composition Examples 1 to 4 can be applied to this wheel.

Composition Example 1 was applied to this wheel and tested in accordance with the aluminum wheel technical standards (commonly known as JAWL: technical standards for light alloy disc wheels for passenger cars established by the Ministry of Transport), and the current commercially available cast integral molding was tested. The results of comparison with aluminum wheels are shown in Table 4 as an index.

The contents of the strength test in Table 4 are as follows: - Impact strength refers to the fracture resistance when a specified load is naturally dropped from a specified height at a specified angle to a wheel with a tire attached.

・Rotating bending fatigue strength refers to the fatigue strength when the wheel is rotated and a lateral bending moment is applied to the disc.

・Radial load endurance strength is measured by rotating a wheel with a tire attached. It refers to the durable strength when a specified load is applied in the radial direction.

According to the results shown in ``2'', it can be seen that Example 1 has sufficient strength compared to aluminum wheels.

Roughly speaking, when this wheel was mounted on an actual vehicle and driven for 100,000 km, no abnormalities were observed, and the wheel was deemed to be sufficiently durable for practical use.

FIG. 2 is a view of the wheel 1 of the present invention cut radially from the center. The composition according to the present invention is used in the rim part 2 of this wheel 1, and the disc part B is made of a light alloy. However, it is natural to use the composition according to the present invention instead of using the light alloy for the disk portion 6. In FIG. 2, the rim portion 2 and the disk portion 6 are engaged with each other using bolts and nuts. Naturally, any of composition examples 1 to 4 of the present invention can be applied to the rim portion of this wheel.

Composition Example 1 was tested in accordance with the above-mentioned technical standards for aluminum wheels, and the results of comparison with a currently commercially available two-piece aluminum wheel are shown in Table 5 as an index.

(Leaving space below) Table 5 ☆ Regarding the weight, the above-mentioned monolithic aluminum wheel is 10
It was set to 0.

Furthermore, no abnormalities were observed when this wheel was mounted on an actual vehicle and the vehicle was driven for 100,000 miles.

As described above, according to the present invention, a resin wheel having practically sufficient strength can be obtained by injection molding at a low cost.

[Brief explanation of the drawing]

1 and 2 are half sectional views showing a wheel according to the invention, respectively. 1... Wheel, 2... Rim part, 6... Disc part. Agent: Patent Attorney Makoto Ogawa − Patent Attorney: Ken Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] In the wheel/L/ in which at least the rim portion is made of fiber-reinforced resin, glass fibers having an average diameter in the range of 3 μ to 8 μ are added to 80 to 40 parts by weight of polyamide 6 or a polyamide resin containing polyamide 6 as the main component. A wheel made of fiber-reinforced high-impact polyamide resin, characterized in that it uses a composition mixed in a proportion of 20 to 60 parts by weight.