JPH05302027A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having high hardness and high damping properties (i.e. high loss factor) by mixing a specified thermoplastic urethane elastomer with a specified thermoplastic fluoroelastomer in a specified mixing ratio. CONSTITUTION:The title composition is prepared by mixing a thermoplastic urethane elastomer of a hardness of 90 A or above with a thermoplastic fluoroelastomer of a peak temperature of loss factor of 10 deg.C or above desirably in a mixing ratio of 5-230 to 100 by pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition used for shock absorption of computer hard disks, magneto-optical disk heads and the like.

[0002]

2. Description of the Related Art Conventionally, when a hard disk drive of a computer is operated, as shown in FIG.
A magnetic disk 1 is installed, and this magnetic disk 1
The information incorporated therein is read by the magnetic head 2. When reading information, the magnetic head 2 is used.
Moves in the direction of arrow R. In this movement, in order to position the magnetic head 2 and prevent the magnetic head 2 from running away, crash stops 3a and 3b are provided at two locations on both sides of the head rotation center portion 3. The crash stops 3a and 3b are required to have a high hardness in order to reduce the amount of strain at the time of positioning, and also to have a high damping property (high loss coefficient) to buffer the shock when preventing runaway. To be done. As described above, the crashstops 3a and 3b are generally required to have high hardness and high damping properties, which are contrary to each other.

[0003]

[Problems to be Solved by the Invention] At the present time,
The crash stops 3a and 3b have a high hardness and a high loss factor thermoplastic urethane elastomer (hardness 90A).
Above) is used. However, the thermoplastic urethane elastomer is insufficient in its damping property,
Materials with higher damping are desired.

The present invention has been made in view of such circumstances, and an object thereof is to provide a thermoplastic elastomer composition having a high hardness and a high damping property (high loss coefficient).

[0005]

In order to achieve the above object, the thermoplastic elastomer composition of the present invention is configured to contain the following components (A) and (B). (A) A thermoplastic urethane elastomer having a hardness of 90 A or more. (B) A thermoplastic fluorine-based elastomer having a loss coefficient peak temperature of 10 ° C. or higher.

[0006]

That is, the present inventors have conducted extensive research to obtain a material having a high hardness and a high loss coefficient.
As a result, when a thermoplastic urethane elastomer having a high hardness and a thermoplastic fluorine-based elastomer having a loss coefficient peak temperature of 10 ° C. or higher are used and the above two are mixed, they have the characteristics of both, have a high hardness and are attenuated. The inventors have found that an elastomer composition material having excellent properties can be obtained and reached the present invention.

The hardness is a value measured according to JIS K6301.

Next, the present invention will be described in detail.

The thermoplastic elastomer composition of the present invention comprises a specific thermoplastic urethane elastomer (component A).
And a specific thermoplastic fluoroelastomer (component B).

As the specific thermoplastic urethane elastomer (component A), one having a hardness of 90 A or more is used. Specifically, Elastollan 1154D, 1164D, 1 which is a polyether elastomer
174A (manufactured by Takeda Birdishe Urethane Co., Ltd.) and the like. This has a peak value of the loss coefficient (tan δ) of about 0.2.

As the above-mentioned specific thermoplastic fluoroelastomer (component B), one having a peak temperature of loss coefficient of 10 ° C. or higher is used. Specifically, a thermoplastic fluoroelastomer composed of an ethylene-tetrafluoroethylene copolymer and a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer (Dayer Thermoplastic T-550, manufactured by Daikin Industries, Ltd.) , A thermoplastic fluorine-based elastomer (Dayer Thermoplastic T-630, manufactured by Daikin Industries, Ltd.) composed of polyvinylidene fluoride and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer.
These have a hardness of 60 to 70 A and a loss factor (ta
The peak value of nδ) is 1.1 to 1.6.

The above-mentioned specific thermoplastic urethane elastomer (component A) and the specific thermoplastic fluoroelastomer (B
The blending ratio of the component) is 5 to 230 parts by weight of the thermoplastic fluoroelastomer (component B) with respect to 100 parts by weight of the thermoplastic urethane elastomer (component A) (hereinafter abbreviated as "part").
It is preferable to set the mixing ratio in parts. That is, when the amount of the thermoplastic fluoroelastomer is less than 5 parts, the hardness is satisfied but the damping property (loss coefficient) is insufficient.
This is because it is difficult to obtain a material having a high hardness and a high damping property such that when the content exceeds 0 part, the damping property is satisfied but the hardness becomes low.

The thermoplastic elastomer composition of the present invention may contain other additives, pigments, etc., if necessary, in addition to the components A and B.

The thermoplastic elastomer composition of the present invention is manufactured, for example, as follows. That is, it can be obtained by blending the above-mentioned components A and B with other additives, if necessary, and melt-mixing.

The thermoplastic elastomer composition thus obtained has a hardness of 90 A or more and a loss factor (tan).
The peak value of δ) is set to 0.21 or more, and the room temperature loss coefficient (tan δ) is set to 0.18 or more.

[0016]

As described above, the thermoplastic elastomer composition of the present invention has the peak temperature of the loss coefficient of 1 with the thermoplastic urethane elastomer (component A) having a hardness of 90A or more.
It contains a thermoplastic fluorine-based elastomer (component B) at 0 ° C or higher. Therefore, it is possible to improve the damping property (high loss coefficient) while having the high hardness of the conventionally used thermoplastic urethane elastomer.
Therefore, the thermoplastic elastomer composition of the present invention is most suitable as a positioning and shock absorbing material for hard disks of computers, heads of magneto-optical disks and the like.

Next, examples will be described together with comparative examples.

[0018]

Examples 1-5, Comparative Examples 1-5 Tables 1 and 2 below
A thermoplastic elastomer composition was produced by mixing and mixing the components shown in 1) in the proportions shown in the same table.

[0019]

[Table 1]

[0020]

[Table 2]

The hardness (JIS A) and loss coefficient (tan) of the thermoplastic elastomer composition thus obtained
δ) (peak value, peak temperature) was measured and shown in Tables 3 and 4 below. The hardness is JIS K 6
According to the method of No. 301, the hardness was measured using a constant load type hardness tester. Further, the loss coefficient was measured using a spectrometer (measurement frequency 100 Hz) manufactured by Yokohama System Co.

[0022]

[Table 3]

[0023]

[Table 4]

From the results of Tables 3 and 4 above, the products of Examples have high hardness and a loss factor (tan) at room temperature.
δ) is high. The peak temperature is 10 ° C. or higher and the peak value is 0.2 or higher. From this, it is understood that the example products have high hardness and excellent damping properties.

As the thermoplastic urethane elastomer, 1164D (manufactured by Takeda Birdishe Urethane Co.) is used.
Daier Thermoplastic T-550 (manufactured by Daikin Industries, Ltd.) is used as the thermoplastic fluoroelastomer,
A thermoplastic elastomer composition was obtained by changing the compounding ratio of both. Its hardness (JIS A) and loss factor (tan δ)
The relationship is shown in FIG. Further, as the thermoplastic urethane elastomer, 1164D is used as described above, and as the thermoplastic fluorine-based elastomer, Daier Thermoplastic is used.
T-630 (manufactured by Daikin Industries, Ltd.) was used. Then, in the same manner as above, the mixing ratio of the two is changed to obtain the hardness (JIS
The relationship between A) and the loss coefficient (tan δ) is shown in FIG. From the hardness-loss coefficient relationship curves in FIGS. 1 and 2 above, the blending ratios in which the loss coefficient is 0.2 or more and the hardness exceeds 90 A, the thermoplastic urethane elastomer (1164D) is used in both FIGS. 1 and 2. / Thermoplastic fluoroelastomer (Dyer Thermoplastic) = 70 / 30-30
It can be seen that it is within the range of / 70. 1 and 2, the curve X is the hardness curve and the curve Y is the attenuation curve.

[Brief description of drawings]

FIG. 1 Thermoplastic urethane elastomer (1164D)
It is a curve figure which shows the relationship of hardness-loss coefficient in the change of the compounding ratio of and a thermoplastic fluoroelastomer (Dayer Thermoplastic T-550).

FIG. 2 Thermoplastic urethane elastomer (1164D)
It is a curve figure which shows the relationship of hardness-loss coefficient in the change of the compounding ratio of and a thermoplastic fluoroelastomer (Dayer Thermoplastic T-630).

FIG. 3 is an explanatory diagram showing a configuration of a hard disk drive.

Claims (2)

[Claims] 1. A thermoplastic elastomer composition comprising the following components (A) and (B). (A) A thermoplastic urethane elastomer having a hardness of 90 A or more. (B) A thermoplastic fluorine-based elastomer having a loss coefficient peak temperature of 10 ° C. or higher. 2. A thermoplastic elastomer in which the blending amount of the thermoplastic fluoroelastomer as the component (B) is set to 5 to 230 parts by weight with respect to 100 parts by weight of the thermoplastic urethane elastomer as the component (A). Composition.