JPH0770823A - Fiber having damping and elastic performances and its production - Google Patents

Abstract

PURPOSE:To provide a damping fiber capable of being applied to leg materials, joint materials, sealing materials, flooring materials, etc., in vibration- accompanied machines, devices, automatic members, houses, factories, etc., to reduce adverse effects and unpleasant touches caused by the vibrations. CONSTITUTION:Polynorbornene as a matrix, and additives selected in response to the purpose are sufficiently melted and kneaded, subsequently formed into a fibrous shape with an extruder, and furthermore thermally treated for suitably crosslinking the formed product to provide the damping and shrinkable fiber raw material improved in the strength. The fiber raw materials are formed into a knitted web. The fiber raw material may be mixed with fine fibers, power, etc., to provide the damping fiber improved in processability and in mechanical physical properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a joint material, a washer, a bolt seal, or a fiber material for shock absorption and vibration absorption in electric equipment, automobile parts, houses, factories, etc., where vibration damping is considered necessary. It can be applied and is used as a material to further reduce the effect of vibration and impact sources.

[0002]

[Prior art]

The damping material absorbs vibrations as heat due to internal friction, and its damping capacity is usually represented by a loss coefficient. The larger the value, the better the damping performance. In addition, the loss coefficient often varies greatly depending on temperature and frequency.

Urethane fibers have been put on the market as a typical fiber material having large elasticity, but they have no vibration damping property. Most of the conventional vibration damping materials are sheet-shaped by roll processing or press-molded by a predesigned mold, and the application range is limited because of a fixed shape. There is no fibrous material that has sufficient vibration damping performance and is highly stretchable, and knitted fabrics using these fibers are notable.

[0005]

SUMMARY OF THE INVENTION The present invention uses polynorbornene as a base material, and has a large loss that cannot be achieved by conventional vibration damping materials (isobutylene isoprene rubber: IIR, natural rubber: NR, urethane type, etc.). A fiber material that has the object of increasing the mechanical strength such as tensile strength by melt-extruding a fiber material that retains the coefficient and is highly stretchable and causes appropriate cross-linking by heat treatment of post-processing. The purpose is to provide.

[0006]

The glass transition point of polynorbornene exists near 34 ° C. Since the peak of the loss coefficient depends on the glass transition temperature, the peak of the loss coefficient of the present resin is almost in the operating temperature range, which indicates that the loss coefficient is large at room temperature (vibration damping performance is large). Since this resin has a huge molecular weight of 3,000,000 or more, it has extremely poor fluidity and is difficult to extrude into a fibrous state by itself. The peak temperature is shown in Fig. As shown in 1, the amount of the compounding agent, particularly the amount of process oil, greatly varies.

By adding the present resin and an oil having a high viscosity such as an aromatic oil as an expander oil, a large loss coefficient is exhibited and the fluidity that can be extruded from the nozzle is obtained, so that the fibrous material can be processed at a low pressure.

A vulcanizing agent has been added to the compounding system in advance, but if crosslinking occurs during extrusion, a good fibrous state will not be obtained, and stretching heat treatment for post-processing will be difficult. It is necessary to process at a low temperature (the added vulcanizing agent does not generate radicals) so that the above does not occur.

The extruded unvulcanized fiber has a large vibration damping property, so that it can be applied as it is depending on the application, but it is heat treated to increase its strength (tension for stretching may be applied). And a suitable degree of cross-linking is performed in this process to obtain a fiber material having improved mechanical strength.

Regarding mechanical strength such as vibration damping performance, expansion and contraction performance, breaking strength, etc., particularly when any one of the performances is to be the main purpose, it is possible to control by selecting the compounding agent.

[0011]

The fiber material of the present invention has a loss temperature peak temperature of 5 ° C to 30 ° C by changing the amount of oil added.
It can be controlled to the front and back, and has a large peak loss coefficient and exhibits damping properties. By adding fine fibers, whiskers, and powdered filler in the compounding system, it is possible to improve the tackiness of the aromatic oil, improve processability, and increase strength.

The fibers, whiskers, and fillers are blended with oil, so that even up to about 30 parts can be easily uniformly dispersed by a twin-screw extruder, roll-kneading device, etc. Is. The kneaded product is molded into a sheet and introduced into an extruder by a sheet feeder,
It can be extruded at a low temperature of around 100 ° C.

The heat treatment is carried out in an atmosphere having a temperature several degrees higher than the radical generation temperature of the vulcanizing agent (air heating, heating steam, oil bath, etc.).
And increase the mechanical properties by crosslinking with an appropriate amount of vulcanizing agent and treatment time. In this process, by applying tension to the fibers to orient the resin molecules in the fiber direction, the strength is further improved. In the heat treatment step, if the material is over-crosslinked, mechanical properties such as elastic modulus and tensile strength increase, but the vibration damping performance extremely decreases. Therefore, it is necessary to determine the treatment conditions depending on the application.

[0014]

EXAMPLES The present invention will be described in more detail by way of examples.
Moreover, the present invention is not limited to these examples. For example, dry-mixing the raw materials shown in Table 1 in the weight ratio,
Melt and knead with a kneader or roll at 100 to 110 ° C. In this case, since a large amount of the extender oil is blended, the extender oil can be dispersed in the base material without surface treatment of fine fibers or powder samples. At this stage, selection of a vulcanizing agent that does not cause crosslinking, kneading temperature, and kneading time must be taken into consideration. That is, it is necessary to use a vulcanizing agent that is stable in the kneading process and becomes active in the heat treatment process. After the additive was uniformly dispersed, it was rolled into a sheet, cut into strips, and extruded from a nozzle at a temperature of around 100 ° C. by an extruder equipped with a sheet feeder to be fibrous. It can also be applied to profile extrusion with various nozzle shapes from capillaries.

[0015]

Table 1 is a table of examples of raw material formulations.

This resin system is required to have a large L / D of a nozzle (capillary) having a large swelling due to a ballast effect at the time of extrusion and not to have a large screw rotation speed (to relax in the capillary). The extruded resin can be expected to have a little molecular orientation by stretching during winding, and it is considered that the strength is increased. It is possible to accelerate simultaneous crosslinking (dynamic crosslinking), but there is a problem in reproducibility, and since it is difficult to form a fiber having stable performance, it is desirable to take a separate step for winding in an uncrosslinked state and heat treatment for crosslinking.

The heat treatment is carried out in air or in an oil bath atmosphere at a temperature 5 to 10 ° C. higher than the radical generation temperature of the vulcanizing agent to cause molecular crosslinking to form a stable structure. It is also possible to accelerate the cross-linking in a stretched state by applying tension. In this case, the mechanical strength such as tensile strength is further increased due to the orientation of the amorphous molecules, but the vibration damping performance is deteriorated. Therefore, it is desirable to take measures from the product design considering the application.

By changing the heat treatment temperature and time, the degree of cross-linking (cross-linking density) varied greatly. As shown in 2, the breaking strength is greatly affected. The strength tends to be higher when the treatment temperature is higher and the treatment is performed for a longer period of time.
At 20 ° C., the strength decreased when the heat treatment time was 20 minutes. Since the present resin is slightly lacking in heat resistance, it may be deteriorated by heat. Therefore, for crosslinking by heat treatment, an additive capable of vulcanizing at a relatively low temperature is desirable.

[0019]

[Table 2] A table of heat treatment conditions (temperature, time) and breaking strength (air atmosphere).

The loss coefficient shows the effect of heat treatment temperature on damping performance. As shown in 2, from 130 ℃ to 150
The peak of the loss coefficient becomes smaller as the temperature rises to ℃, and shifts to the higher temperature side. The damping performance shows a tendency to decrease a little with the promotion of crosslinking.

Since the breaking strength and the vibration damping performance tend to conflict with each other with respect to the degree of crosslinking, it is desirable to determine the heat treatment conditions in consideration of the application.

In the compounding system of the present resin, a large amount of extending oil is added, and therefore the tackiness is large and there is a problem in processing. It can be dealt with by adding about 5 to 10 parts of a powder system (zinc oxide or calcium carbonate). In the case of zinc oxide, it also has an action of promoting vulcanization in the organic vulcanizing agent. With such a blending amount, the vibration damping performance is hardly affected.

Potassium titanate whiskers, diameter 1-2 μ
When extruded using fine fibers having a length of m and a length of 15 to 20 μm, the fibers are oriented in the fiber direction of the fiber material (diameter 100 to 1000 μm), and an increase in strength in this direction can be expected. A relatively thick glass fiber or carbon fiber greatly reduces vibration damping performance, but can be expected to have improved elastic modulus and tensile strength.

The knitted fabric in which the damping fiber is knitted as a weft yarn enables a fabric having excellent vibration damping and vibration absorbing properties due to the elasticity due to the knitted fabric structure and the vibration absorbing property of the fiber.

[0025]

INDUSTRIAL APPLICABILITY The present invention provides a polynorbornene-aromatic oil addition system in which the additives and the amount to be added are determined according to the purpose and kneading, extruding, and heat-treating to obtain a fiber material having a large vibration damping property and elasticity. Yes, this is a knitted fabric that is made into a fabric using this. With these, it can be used as a vibration-damping material for preventing vibrations of mechanical devices and flooring of apartments.

[Brief description of drawings]

FIG. 1 is a graph showing the temperature dispersion of a loss coefficient depending on the amount of oil added.

FIG. 2 is a graph showing the effect of heat treatment conditions on the loss coefficient.

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Claims (3)

[Claims] 1. Polynorbornene, an aromatic oil, carbon black, a vulcanizing agent, a vulcanization accelerator, an antioxidant and, if necessary, potassium titanate whiskers, glass fibers, carbon fibers, flaky metallic zinc powder, An unvulcanized material obtained by melt-extruding fibrous titanium oxide. 2. A fibrous material obtained by cross-linking an unvulcanized material extruded into a fibrous shape with an oil bath or air heating to maintain vibration damping performance and improve strength. 3. A knitted fabric mainly made for absorbing impact and vibration using these fiber materials.