JP2000289121A - Manufacture of bent hose with rubber-resin lamination layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent crease and swells due to a significant difference in the rigidity between a resin and an unvulcanized rubber from being generated by regularly vulcanizing a laminate of rubber and resin after previously vulcanizing and bending the laminate. SOLUTION: First a core is run and an inner layer rubber is extruded by a first extruder A to be laminated on the core N and an intermediate resin and an outer layer rubber are extruded by a second extruder B and a third extruder C respectively so that the intermediate resin and the outer layer rubber are sequentially laminated on the outer periphery of the core N. The laminated hose H is cut to the specified length and vulcanized by vulcanization with pressurized vapor, high frequency or the like. When the bent hose H is manufactured, the vulcanization process is suspended halfway through a vulcanization reaction as a preliminary vulcanizing step and the core N is drawn out of the hose H, which is, in turn, bent. That is, the half-vulcanized hose H is inserted into a vulcanizing guide M with a desired bend by the preliminary vulcanization process and the hose H is regularly vulcanized in such a state that the hose H is inserted into the guide M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rubber-resin laminated bent hose suitable for use as a fuel pipe hose of an automobile.

[0002]

2. Description of the Related Art In a hose, rubber and resin are laminated to take advantage of each. That is, the rubber is expected to have flexibility and elasticity, and the resin is expected to be air-impermeable. For example, in the case of a fuel hose for an automobile, there is a hose in which a resin is an intermediate layer and an inner layer and an outer layer are made of rubber. In this case, gasoline resistance and sealability are required for the inner rubber layer, gasoline permeability resistance is required for the intermediate resin layer, and elasticity, ozone resistance and flame resistance are required for the outer rubber layer. In addition, the fuel hose often has a complicated bend depending on the place of use in order to avoid interference with peripheral members.

[0003]

In order to manufacture a rubber-resin laminated hose, usually, a rubber or resin is laminated on a rubber or resin core at the same time or in a stepwise manner according to the structure of the hose. Structure. In this case, if the hose is a straight straight tube, vulcanization is performed as it is, and then the core is removed, whereby a vulcanized rubber-resin laminated hose is obtained. On the other hand, in the case of a bent tube in which the hose has a bent shape, vulcanization is performed by removing the core and inserting it into a vulcanized mandrel having a bent shape, or after removing the core or before removing the core. The bent hose is manufactured by either of the following methods: vulcanization by fitting to a bent outer frame.

[0004] When the former method is adopted, the core is very difficult to pull out because it is in close contact with rubber or resin.
When the core is removed, the surface of the innermost layer of rubber or resin may be damaged, and the rubber-resin lamination interface may be physically separated before vulcanization. It is difficult to obtain a normal product before vulcanization. Therefore, for example, even if it can be pulled out without causing scratches or peeling while struggling by applying a release agent to the core in advance, this time, when inserting it into the vulcanized mandrel, Peeling occurs at the rubber-resin interface, and wrinkles and lumps are easily generated due to the large difference in rigidity between the resin and unvulcanized rubber inside the curved surface (R) at the bend, and a normal finished product is obtained. It is hard to obtain.

On the other hand, when the latter method of fitting the core into the outer frame before removing the core is used, no problem occurs when the core is removed, but the same phenomenon as described above occurs inside the radius at the bend. However, in this method, since the vulcanization is carried out by contacting the outer frame, the outermost layer of rubber or resin is damaged during vulcanization, and it is difficult to obtain a normal product. The present invention has solved the above-mentioned problems by performing vulcanization stepwise.

[0006]

SUMMARY OF THE INVENTION Under the above-mentioned problems, the present invention relates to a method for producing a rubber-resin laminated bent hose in which rubber and resin are laminated. It is intended to provide a method for producing a rubber-resin laminated bent hose characterized by bending and then main vulcanization.

[0007] Here, the pre-vulcanization is a vulcanization reaction in which a rubber is cross-linked by applying heat to convert an unvulcanized rubber in the form of clay into an elastic vulcanized rubber. This is an operation to stop applying heat and stop the reaction before starting. In the following figure, the horizontal axis shows the heating time and the vertical axis shows the state of the heating reaction with the torque (elasticity of rubber) taken. If the heating is stopped in the area 3) during the time 2), the pre-vulcanization can be performed.

[0008]

[0009] Vulcanization method (heating method) in this case
Started the usual pressurized steam vulcanization,
Any method such as (high frequency) vulcanization, hot air vulcanization, salt bath vulcanization and the like may be used. Further, the specific time of the pre-vulcanization is determined in consideration of the product performance, process control, economy, and the like by the vulcanization speed by the rubber compounding, the vulcanization temperature, the thickness of the product rubber, and the like.

[0010] When the above pre-vulcanization is performed, an adhesive reaction occurs at the interface between the rubber and the resin due to a thermal reaction, so that an adhesive force capable of preventing peeling in the core removal or bending process before the main vulcanization can be secured. The problem of peeling can be solved. In particular, if the resin is T
In the case of fluorinated resin, which is a terpolymer of FE (tetrafluoroethylene), HFP (hexafluoropropylene), and VDF (vinylidene fluoride), only the thermal reaction of the vulcanization process is achieved by specially compounding rubber. In some cases, an adhesive may not be applied between the rubber and the resin, in which case the rubber and the resin before the vulcanization process have only physical adhesion, It is very easy to peel off because it has a good release property,
By performing the above-mentioned preliminary vulcanization that causes an adhesive reaction at the interface between the rubber and the resin, this problem of peeling can be solved.

[0011] In addition, by performing pre-vulcanization, the rubber becomes completely elastic from a completely clay-like one, so that when the core is removed, the rubber is inserted into the vulcanizing mandrel before the main vulcanization. Alternatively, it is possible to prevent not only scratches at the time of contact with the outer frame, but also wrinkles and bumps inside the radius at the bent portion.

In the present invention, the main vulcanization is carried out after the preliminary vulcanization. The main vulcanization is performed by removing the core and then inserting the core into a vulcanized mandrel having a bent shape. There is a method of fitting into an outer frame having a shape. In any case,
Main vulcanization (as with pre-vulcanization, any method is acceptable)
Since the pre-vulcanization does not completely end the vulcanization reaction, it means an operation to complete the vulcanization reaction and complete the vulcanization reaction to fix the bent shape.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described. For a fuel pipe hose, a three-layered structure in which a resin is sandwiched between intermediate layers and an inner layer and an outer layer are made of rubber is suitable. In this case, the intermediate layer is made of nylon, ethylene vinyl alcohol, polyketone and TFE, HF having excellent gasoline permeability resistance.
Fluororesins such as P and VDF terpolymers are suitable. The outer layer is preferably made of ECO (epichlorohydrin rubber) having excellent ozone resistance, or a blend of nitrile butadiene and polyvinyl chloride resin (NBR + PVC).
NBR + PVC, fluoro rubber and the like are suitable. Also, the lamination operation of the rubber and the resin is efficiently performed by extrusion molding instead of wrapping the tape-shaped resin on the rubber.

Next, a case in which the above-described three-layer bent hose is manufactured by extrusion molding will be described with reference to the drawings. FIG. 1 is an explanatory view of the extrusion molding, in which a core N is flowed, and an inner layer rubber is supplied to the first extruder A, an intermediate resin is supplied to the second extruder B, and an outer layer is supplied to the third extruder C. The rubber is extruded and laminated on the outer periphery of the core N in this order. FIG. 2 is a cross-sectional view of the laminated hose H thus laminated. It can be seen that an intermediate layer b of resin is sequentially laminated on the outer periphery of the inner layer a of rubber, and an outer layer c of rubber is further laminated on the outer periphery thereof. .

The laminated hose is cut to a predetermined length and vulcanized. In this case, the method of vulcanization includes pressurized steam vulcanization, UHF (high frequency) vulcanization, hot air vulcanization, salt bath vulcanization, and the like, and may be appropriately selected from these. In the case of a straight hose, the product is obtained by performing the process up to complete vulcanization, then removing the core N and cutting it to a required length.

On the other hand, in the case of a bent hose, preliminary vulcanization for stopping vulcanization during the vulcanization reaction is performed. The pre-vulcanization time may be determined in consideration of the product performance, process control, economy, etc., based on the vulcanization speed, vulcanization temperature, and the thickness of the product rubber by rubber compounding. The core N is removed from the hose H (previous vulcanization is completed) which is still straight and bent. FIG. 3 is an explanatory view showing the state of bending. The point is that a hose H semi-vulcanized by preliminary vulcanization is inserted into a vulcanized mandrel M having a desired bend, and the vulcanized mandrel M is attached thereto. The main vulcanization is performed as it is (the method and time may be appropriately selected as in the case of the pre-vulcanization).

Here, peeling of the rubber-resin interface, which tends to occur when the core is removed or inserted into a vulcanizing mandrel, has a problem because it has an adhesive force that can withstand the work by pre-vulcanization. Absent. Furthermore, since the rubber in the inner and outer layers is made to a certain degree of elasticity by pre-vulcanization, the rubber is not damaged when the core is pulled out, and there is no close contact with the core, so the work is efficient. And wrinkles and bumps on the inside of the bend are hardly generated. In addition, although the outer frame may be used for the bending, also in this case, it is hard to be damaged by the contact between the outer frame and the outer layer rubber for the above-mentioned reason.

However, since the rubber is bent from a state in which the rubber has become an elastic body to some extent by the pre-vulcanization, when the hose is taken out from the vulcanized mandrel or the outer frame after the main vulcanization, the vulcanized mandrel or the outer frame is bent. The phenomenon of springback, which is larger than the angle, tends to occur. For this reason, it is preferable that the bending angle of the vulcanizing mandrel and the outer frame for bending is tighter than the required hose shape by the amount corresponding to the springback.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of extrusion of a three-layer hose showing an embodiment of the present invention.

FIG. 2 is a sectional view of a three-layer hose showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a music composition state according to the embodiment of the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeto Oga 58 Kamitomii, Kurashiki-shi, Okayama Marugo Rubber Industries Co., Ltd. F-term (reference) DA11 EH112 EH23 EJ062 EJ282 EJ422 GB32 JB16B JK06 JK14 JL00 4F213 AA16 AA16E AA17 AA17E AA45 AG03 AG08 AH16 AH17 WA06 WA53 WA87 WA90 WB01

Claims (2)

[Claims] 1. A method for producing a rubber-resin laminated bent hose in which rubber and resin are laminated, characterized in that a laminated rubber and resin is pre-vulcanized and bent, followed by main vulcanization. Method of manufacturing rubber-resin laminated bent hose. 2. The method according to claim 1, wherein the resin comprises a thermoplastic fluororesin which is a terpolymer of TFE, HFP and VDF.