JPS5995130A - Manufacture of hollow diaphragm - Google Patents

Abstract

PURPOSE:To manufacture a seamless, homogenized, hollow diaphragm with excellent strength by a method wherein a core constituting hollow inside is made of a specific material. CONSTITUTION:The material comprising a core 14 made of paraffin with melting point of 68-72 deg.C is formed into one body with a supporter 10. When non hardened solution of room temperature hardening type urethane elastomer is injected from an injecting port 28 of a formed and assembled body, the non hardened solution is polymerized to be hardened in a cavity 22 producing elastic urethane elastomer corresponding to the shape of the cavity. The core 14 may keep its shape while the urethane elastomer is formed into one body with the supporter 19 since the temperature rise due to polymerizing reaction is restricted below the melting point of the paraffin comprising the core 14. Then a hollow diaphragm 32 is manufactured by means of heating a formed body released from the core 14 to melt and discharge the paraffin as well as sticking the supporter 10 to a hollow inside 30 forming them into one body.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a hollow diaphragm.

A hollow diaphragm made of a flexible bag-like body is generally made of rubber or other elastomer material, and the conventional manufacturing method is to glue or weld the peripheral edges of plates of rubber etc. to each other to create a bag-like shape. Alternatively, in the case of a complex shape, mold each half of the diaphragm with a recessed part in the center by injection molding, etc., then place the molded bodies facing each other and glue or weld the periphery in the same manner as described above. was.

However, diaphragms manufactured by these methods have seams, and the tensile strength of such seams is about 80% or less compared to that of a uniform material, which tends to cause two strength deficiencies: b0, i.e. In conventional conventional molding methods, it is impossible to remove the core constituting the hollow interior after molding, so the only manufacturing method that can be used is to combine two sheets as described above.

In consideration of the above-mentioned facts, the present invention aims to provide a hollow diaphragm that is seamless, has uniform parts, and has excellent strength.

In the method for manufacturing a hollow diaphragm according to the present invention.

The material that makes up the core that makes up the hollow interior has a melting point of 4.
It is composed of a hydrophobic substance with a temperature of 0 to 150°C, and the uncured liquid of the low-temperature curing urethane elastomer is cured in a mold at room temperature using a casting material. At the same time, it is heated above the melting point of the substance to melt it.

A hollow diaphragm is obtained by discharging the fluid from inside the molded body in a fluid state.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an assembly of a core and its support member according to this embodiment.

In the figure, a pair of nozzles 12.1 are mounted on the support plate 10.
2 are integrally protruded by welding or the like, and a core 14 is integrally attached to the lower surface of the support plate 10, and the hollow interior of each nozzle 12 is also filled.

The melting point of the material constituting this core 14 is 68°C.
The core 14 and the support plate 10 are made of paraffin at a temperature of 72 DEG C. and are integrally molded in advance using paraffin casting or the like, and then integrated into the above-mentioned assembly.

Next, FIG. 2 shows a state in which the above assembly is loaded into an injection mold.

The injection mold 16 is made up of an upper mold 18 and a lower mold 20, and has a cavity 22 on its noming surface that has the same outer shape as the diaphragm.

The upper mold 18 has nozzle insertion holes 24, 24 that penetrate inside and outside the cavity 22 and support the nozzle 12.12.
After forming the injection mold 16 and the resin discharge port 26, the assembly is set so that the core 14 is located in the center of the cavity 22, and the upper and lower molds 18 are connected to each other using connecting bolts (not shown). , 20 are clamped to prepare for molding.

In this state, if an uncured liquid of the room temperature curing type urethane elastomer is poured into the cavity 22 through the injection port 28 and filled into the cavity 22, the uncured liquid is poured into the cavity 22.
The material is polymerized and hardened by the hardening reaction within the molded body 2, and an elastomer molded body corresponding to the shape of the cavity is finally formed.

This uncured liquid is obtained by mixing a curing agent containing 3,3'-dichloro-4,4-diaminodiphenylmethane in an appropriate ratio with a main ingredient containing diisocyanate, and immediately pouring this mixed liquid into the above-mentioned cavity within the pot life. Immediately after mixing, this mixed solution starts a polymerization reaction, gradually increases its viscosity, and eventually gels and loses fluidity to produce a highly elastic urethane elastomer. Moreover, since this polymerization reaction is an exothermic reaction, when casting is performed at room temperature, the temperature rises to 40 to 60°C. Although this temperature increase varies depending on the size of the diaphragm, heat dissipation from the injection mold 16, etc., this temperature increase further accelerates the polymerization reaction and accelerates curing.

Therefore, such a temperature increase is kept below the melting point of the paraffin constituting the core 14.

The core 14 maintains its shape, so that this urethane elastomer molding is integrated with the support plate 10° nozzle 12 and the core 14 described above.

Next, after sufficiently curing the molded body, upper and lower molds 18,
20 and demold the molded body.

Thereafter, when the molded body is heated to a temperature above the melting point of paraffin (approximately 80°C) with the nozzle 12 facing downward, the paraffin melts and flows down from the nozzle 12, resulting in the formation as shown in FIG. .

A urethane elastomer molded body, that is, a diaphragm 32, in which the support plate 10 is integrally attached to the hollow interior 30 and the hollow interior is communicated through the nozzle 12, can be obtained.

In the above embodiments, paraffin having a melting point of 68 to 72 DEG C. was used as the core material.

A material that does not melt due to the reaction heat of the uncured resin liquid, but melts at a temperature lower than the heat resistance temperature of the resulting elastomer molded body, that is,! ! Any material may be used as long as it has an lt point of 40 to 150°C, preferably 50 to 90°C, and does not contain water, which is a reaction inhibiting factor.1 For example, paving tar, synthetic wax, etc. It can be used.

Furthermore, according to the above embodiment, diisocyanate and 3.3'-dichloroO-4.
4-'; A combination of aminodiphenylmethane was used,
Any other combination may be used as long as it generates little heat during reaction, is fast curing, and provides a high strength elastomer. For example, product name
・The two-component heated urethane elastomer uncured liquid called Iprene Q (manufactured by Mitsui Nissho Urethane Co., Ltd.) is a mixed liquid that hardens in a few minutes at room temperature (5 to 60°C) and then hardens at high temperature. Forms a high-strength elastic film comparable to that of

Furthermore, in the above embodiment, the elastomer molded body was heated after demolding to elute the inside, but the molded body was heated in the mold before demolding to also cure the molded body.
Of course, the core may be demolded after elution.

According to one aspect of the present invention, as described in the embodiments above.

Seamless hollow diaphragms can be easily obtained,
In addition, the obtained molded product has various advantages such as the strong tensile strength of the urethane elastomer itself, as well as being homogeneous and having no decrease in strength due to seams.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the core of this embodiment, and FIG. 2 is a sectional view of the injection mold and the core loaded therein. FIG. 3 is a completed sectional view of the hollow diaphragm. 10... Support plate (supporting member) 12... Nozzle (discharge hole) 14... Core 16... Injection mold 22... Cavity (inside the mold) 28... Resin injection port 30... Hollow inside 32...
・Hollow diaphragm.

Claims (1)

[Claims] (1) Inside the mold with an injection port, the melting point is 40 to 150.
A step of loading a core made of a hydrophobic substance at ℃ and a support member integrated with the core and provided with a discharge hole. Next, the uncured liquid of the low temperature curing urethane elastomer is poured into the mold through the injection port and cured at a temperature below the melting point of the core. Before or after demolding the molded body by curing the elastomer, the core is heated to a temperature higher than the melting point of the core to melt the core inside the molded body. A step of discharging the constituent components of the core from the discharge hole. A method for manufacturing a hollow diaphragm consisting of.