JPS63303279A - Fiber-reinforced plastic valve body for check valve - Google Patents

Abstract

PURPOSE:To increase the impact resistive fatigue strength and improve the operation efficiency and durability by constituting a valve body by dispersing whiskers into a matrix made of plastic. CONSTITUTION:A valve body made of the fiber-reinforced plastic which is formed by dispersing whiskers into the plastic which constitutes a matrix. As the reinforcing fiber, can be used all the reinforcing fiber such as glass fiber and carbon fiber. As the plastic which constitutes a matrix can be used all the well-known plastic including thermosetting resin and thermoplastic resin. As the whisker, can be used the needle-shaped crystal in single fiber form which consists of the carbides such as SiC, nitrides, oxides, and further the single crystal of carbon and metal and has a diameter of 0.1-severalmum.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fiber-reinforced plastic valve body for a check valve. This invention relates to a valve body with increased fatigue strength (hereinafter referred to as a valve body for a reversal valve unless otherwise specified).

[Prior art] As is well known, a check valve is a valve that has the function of allowing fluid to pass in one direction and blocking the flow in the opposite direction, and there are various types such as spring type, float type, diaphragm type, etc. They are manufactured by various mechanisms such as check valves, safety valves, etc.
It is widely put into practical use under the names such as pressure holding valves.

Among these check valves, there are intake/exhaust valves and pressure holding valves for compressors, pumps, internal combustion engines, etc. that utilize the elasticity of the material that makes up the valve body. Materials used include metal, rubber, plastic, and fiber-reinforced plastic.

However, the conventionally known materials for check valve discs are
There is a problem in the balance between elastic modulus and impact fatigue strength, and the following problems occur especially when the pressure difference between the fluid flowing on the inlet and outlet sides of the check valve is small and the check valve operates frequently. It's coming. In other words, when using a material with a high modulus of elasticity as the material for forming the valve body, in order to make the effective opening area sufficiently wide when the valve opens to allow the required flow rate to flow, it is necessary to apply it to locations where strong force is required to open the valve. Alternatively, it is necessary to select a thin material for the valve body, but in the former case, the valve body will collide with the valve seat with strong force during operation in the closing direction, and the repeated collisions will cause the valve body to become damaged. It will be damaged within a short period of time. On the other hand, if the latter thin-walled material is used, the valve body itself will be insufficient in strength, making it even more likely to be damaged by a collision during closing. In addition, when a thick valve body is used, its rigidity increases, which not only makes it insufficient to open and close the valve on the low fluid pressure side, but also reduces the effective opening area, reducing the operating efficiency of the check valve as a whole. At the same time, there is a lack of responsiveness.

On the other hand, if a material with a low elastic modulus is used as the material for the valve body, a large effective opening area can be secured even with a relatively small fluid pressure, and the restoring force is not so large, so it is possible to reduce the impact on the valve seat when operating in the closing direction. The impact force is small,
Impact damage to the valve body is unlikely to occur. However, the lack of elasticity immediately appears as a delay in response to pressure changes, resulting in a lack of quick response.

A valve body made of fiber-reinforced plastic has been developed and is attracting attention because it overcomes these drawbacks of conventional materials. That is, the constituent materials of this valve body include glass fiber, carbon fiber, and reinforcing fibers.
It uses fibers such as aramid fibers and metal fibers and composites them with plastics such as thermosetting resins and thermoplastic resins.The combination of the plastic and reinforcing fibers that make up the matrix, the orientation direction of the reinforcing fibers, etc. It is possible to adjust the physical properties in various ways by changing the material, and it also has excellent tensile strength and bending strength, so the range of applications seems to be rapidly expanding.

[Problems to be Solved by the Invention] By the way, valve bodies made of fiber-reinforced plastic are usually manufactured by laminating and integrating a plurality of resin-impregnated fiber cloths, and the fiber orientation and lamination effect produce excellent results. However, due to the laminated structure, the delamination strength is somewhat poor, and as a result, the impact caused by repeated opening and closing tends to cause delamination, which can lead to destruction of the valve body. However, it has been pointed out that it has insufficient impact fatigue strength.

The present invention was made in view of these circumstances, and its purpose is to maintain the characteristics of fiber-reinforced plastics, improve the lack of delamination properties, and improve impact fatigue strength. The object of the present invention is to provide a valve body for a check valve that has improved operating efficiency and durability.

[Means for Solving the Problems] The structure of the valve body of the present invention, which can achieve the above-mentioned objects, has its gist in that whiskers are dispersed in a matrix made of plastic.

The fiber-reinforced plastic constituting the valve body according to the present invention has the following functions:
Strengthen the matrix phase by dispersing whiskers in the plastic that makes up the matrix, and the interlayers due to the destruction of the matrix! It prevents lJ separation, and the combination of the reinforcing effect of reinforcing fibers and the matrix reinforcing effect of whiskers maintains a balance between elastic modulus and impact fatigue resistance, resulting in a valve body with excellent quick response and durability.

The reinforcing fibers used in the present invention include glass fibers; carbon fibers; organic fibers such as polyamide fibers; metal fibers such as steel fibers; ceramic fibers such as alumina fibers; or titanate fibers: inorganic fibers such as rock wool, etc. All conventionally known reinforced Km fibers can be used, and these can be used alone or, if necessary, in combination with 2 fffi.
The above can be used in combination. Among these reinforcing fibers, carbon fiber is most preferred in order to ensure high elasticity and impact fatigue resistance, which are important characteristics required for a valve body for a check valve.

In addition, all known plastics can be used as the plastic for the matrix, including thermosetting resins such as epoxy resins and unsaturated polyester resins, and thermoplastic resins such as polyamide, polyethylene, and polycarbonate. Those that have been praised as engineering plastics are useful, and should be selected appropriately depending on the environment in which they will be used, taking into account heat resistance and other factors.

Next, what are the whiskers used to strengthen the matrix?
It is a single fiber-like needle-like crystal with a diameter of 0.1 to several μm made of a single crystal of carbide, nitride, oxide, carbon, or metal such as SiC, and there are no restrictions on its type, but it can be used as a fiber material. They have common characteristics such as having extremely few dislocations, which are one of the structural defects, and having a strength close to the theoretical value, and are expected to be used as reinforcing materials for composite materials.

In the present invention, the characteristics of the whiskers are used to effectively act as a reinforcing material for the matrix from a microscopic point of view, thereby strengthening the matrix itself, and reinforcing fibers 1:ff which act as a reinforcing material from a macroscopic point of view.
In combination with the effects of , it is possible to obtain a valve body for a check valve that exhibits excellent elasticity and impact fatigue resistance as a whole. The means for combining whiskers is not particularly limited, but the most common method is as follows.

■A method in which whiskers are kneaded into the resin that makes up the matrix and then impregnated with reinforcing fibers.

■Spread whiskers evenly between the reinforcing fiber layers,
A method of impregnating this into the matrix constituent resin.

■When adopting the method of making a resin-impregnated reinforcing fiber sheet in an uncured or semi-cured state, laminating it and then heat-pressing it to make a valve body, make sure that whiskers are evenly distributed between the layers before lamination. A method of spraying, laminating, and then heating and pressing.

It should be noted that if method ① above is adopted, the whiskers can be uniformly distributed throughout the matrix, so it can be said to be the most preferable method from the viewpoint of matrix reinforcement effect. In this case, the content of whiskers in the matrix is preferably 0.2 to 5% by weight; if the amount of whiskers used is small, the reinforcing effect will not be sufficiently exhibited, while if it is too large, the fluidity of the resin will be poor. This makes it difficult to impregnate the reinforcing fibers, and there is a risk that resin wilt (unimpregnated voids remain) or voids may occur in the molded product, which may actually impair the strength properties.

In addition, when methods ① and ② above are adopted, a large amount of whiskers are present at the lamination boundary between fiber reinforced plastics, increasing peeling resistance, so even with a relatively small amount of whiskers, a high level of impact fatigue resistance is achieved. characteristics can be obtained.

However, the method of combining the whiskers, reinforcing fibers, and matrix-constituting resin is not limited to the above ■ to ■, and it is of course possible to adopt other combining methods, and if necessary, combining methods of 2 fff1 or more It can also be implemented in combination.

As described above, in the present invention, by dispersing and reinforcing extremely fine and strong whiskers in the matrix constituent material of fiber-reinforced plastic, the material has excellent not only mechanical strength but also elasticity and impact fatigue strength. A valve body for a check valve that exhibits high performance can be obtained.

Next, examples of the present invention will be shown.

[Example] Example 1 60 parts by weight of epoxy resin (trade name: Araldite 6071 manufactured by Ciba Geigy) and glycidylamine type epoxy resin (trade name: Araldite MY7 manufactured by Ciba Geigy)
20) 25 parts by weight, 10 parts by weight of curing agent (dicyandiamide) and curing accelerator (3-(p-chlorophenyl)-
2 parts by weight of 1,1-dimethylurea) are dissolved in 70 parts by weight of a mixed solvent of acetone:methyl ethyl ketone-1:1.

On the other hand, 2 parts by weight of SiC whiskers are dispersed in 30 parts by weight of ethanol, and this dispersion is gradually added to the epoxy resin solution while stirring, and the entire amount is mixed uniformly.

This mixed solution was mixed with carbon fiber IK tow having a fabric weight of 125.
g/m2 of plain weave fabric to produce a woven fabric prepreg. Three sheets of this woven fabric prepreg are laminated and heat-pressed,
A flat plate with a thickness of 0.5 mm was used. A valve body was prepared using this flat plate and subjected to repeated impact tests under the following conditions. No damage to the valve body was observed even during a durability test of 20 hours or more.

(Test conditions) Load mode: Bending impact force: 15Kg-f 7cm2 Repetition frequency: 8000 to 10000 times/min Comparative example 1 The same epoxy resin solution used in Example 1 was
Example 1 by itself without mixing with C whisker dispersion
The same carbon fiber woven prepreg was used.

Three sheets of this prepreg were laminated and heat-pressed, and a valve body for a check valve was produced using the resulting flat plate with a thickness of 5 mm. Next, a repeating town similar to Example 1! When a load test was carried out, this valve element suffered delamination within 5 hours, and cracks or chips appeared at the part where it collided with the valve seat.

[Effects of the Invention] The present invention is configured as described above, and by reinforcing the entire matrix layer by dispersing whiskers in the matrix constituent material of LA fiber-reinforced plastic, reinforcing fibers,
Due to the combined effect of the three types of plastic and rice car, it was possible to exhibit a high level of elasticity and impact fatigue resistance, and the performance and durability as a valve body for a check valve were significantly improved.

Claims (1)

[Claims] A fiber-reinforced plastic valve body for check valves that has whiskers dispersed in a plastic matrix.