JP4428600B2 - Manufacturing method of molded hose - Google Patents

Description

得られた結果を下記の表１に併記する。
【００３９】
【表１】

【００４０】
前記表１から、第１加硫の加硫温度は１２０℃程度が適しており、第２加硫の加硫の条件に近づくにつれ、内面樹脂層のしわが入りやすくなり、形状の安定性も劣ってくることが分かる。一方、第１加硫を行わないと（比較例１）、ゴムが完全に未加硫のため型付けのときに傷が入りやすく、外面層に凹凸や剥がれ等が生じて商品価値のないものとなってしまった。
【００４１】
【発明の効果】
以上説明してきたように本発明によれば、最内面の樹脂層にしわや亀裂等の発生を防ぐことができ、しかも形状の安定した成型ホースが得られる。従って、自動車用エアコンディショニングシステムの冷媒輸送用成型ホースとして有用である。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る成型ホースの一部切欠きの正面図である。
【図２】本発明の他の一実施の形態に係る成型ホースの一部切欠きの正面図である。
【符号の説明】
１ 内面ゴム層
２ 外面ゴム層
３ 繊維補強層
４ 樹脂層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a hose (hereinafter simply referred to as “molded hose”) molded in a shape to be piped in advance, and a molded hose manufactured by this method. More specifically, the present invention relates to a method for manufacturing a molded hose having a stable shape without wrinkles or cracks in the resin layer disposed on the innermost surface in order to improve airtightness, and a molded hose manufactured by this method. Such a molded hose is useful as a molded hose for transporting a refrigerant in an automotive air conditioning system or the like.
[0002]
[Prior art]
As countermeasures against today's environmental problems such as the destruction of the global ozone layer, it is required to minimize the leakage of refrigerant from the air conditioning system, and the refrigerant transport hose used also has a resin layer on the innermost surface. Therefore, it is becoming possible to reduce the permeation amount of the refrigerant in use as much as possible.
[0003]
On the other hand, miniaturization and weight reduction of automobiles are required, improving fuel efficiency and saving resources. Therefore, the refrigerant transport hose used in the vehicle air conditioning system hits piping in a narrow engine room, and it is possible to arrange more compact parts by selecting a hose that has been pre-shaped into a shape to be piped. As a result, there is an increasing demand for molded hoses with a wide variety of shapes today.
[0004]
The conventional method of making such a molded hose has been generally performed as follows. First, the inner rubber layer is formed as a hollow tube, a reinforcing layer is knitted on the outer peripheral surface, and the outer rubber layer is extruded and coated on the outer peripheral surface. Thereafter, the unvulcanized hose is cut, a metal mandrel molded in advance into a predetermined shape is inserted, placed in a steam can, vulcanized by heating under pressure, and integrated. In this manufacturing method, a metal mandrel molded in a predetermined bent shape is inserted into a cut unvulcanized hose in advance, or is pulled out after vulcanization. It was necessary to use soap.
[0005]
[Problems to be Solved by the Invention]
Due to such a manufacturing method, it has been difficult to provide a thin resin layer for improving airtightness on the innermost surface in the conventional molded hose. When the resin layer is provided, a resin tube is first formed as the resin layer, and then the inner rubber layer is extruded and molded on the outer peripheral surface of the resin tube. Therefore, it is difficult to reduce the thickness of the resin layer. Met.
[0006]
In addition, when the molded mandrel is pushed into the unvulcanized hose during the manufacturing process, the reinforcing layer is easily deformed, and therefore it is difficult to apply to a hose that requires pressure resistance. Furthermore, the hose having the resin layer on the innermost surface has a problem that the resin layer is likely to be wrinkled and cracked when the mandrel is pushed in and pulled out after vulcanization.
[0007]
In addition, since it is necessary to use a large amount of a release agent on the inner surface of the hose, it has been difficult to use as a hose for an air conditioning system that requires cleanliness of the inner surface.
[0008]
Furthermore, when vulcanizing in a steam can as in the prior art, polyethylene terephthalate (PET) fibers and vinylon fibers are hydrolyzed when steam comes into contact with the reinforcing fibers, so that the hose ends are protected, or A measure such as providing an extra scale so that the hydrolyzed portion can be cut off at the time of finishing is necessary, which is disadvantageous in cost. Although this problem can be solved with an aramid fiber, there is a new problem that the fiber itself becomes very expensive.
[0009]
Accordingly, an object of the present invention is to provide a method for producing a molded hose having a stable shape without wrinkles or cracks in the resin layer on the innermost surface, in particular, a molded hose for transporting refrigerant, and a molded hose produced by this method. It is to provide.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventor has found that the object can be achieved by devising the vulcanization conditions in the production process of the molded hose, and has completed the present invention. That is, the present invention is as follows.
[0011]
<1> A hose having an inner rubber layer, one or more reinforcing layers wound around an outer periphery of the inner rubber layer, and an outer rubber layer disposed on the outer periphery of the reinforcing layer, In the manufacturing method of the molded hose in which the resin layer is disposed on the inner peripheral surface of the rubber layer,
(I) a step of extrusion coating the resin layer on the outer peripheral surface of a vulcanized rubber mandrel containing a steel cord;
(II) a step of overlaying and extruding the inner rubber layer on the outer peripheral surface of the obtained resin layer;
(III) a step of winding one or more reinforcing layers on the outer peripheral surface of the obtained inner rubber layer;
(IV) a step of extruding and coating an outer rubber layer on the outer peripheral surface of the wound reinforcing layer;
(V) applying a first vulcanization to the unvulcanized hose provided with the outer rubber layer and semi-vulcanizing;
(VI) cutting the semi-cured hose into a predetermined length together with the vulcanized rubber mandrel containing the steel cord;
(VII) After the cut semi-vulcanized hose is molded into a predetermined shape, the second vulcanization is performed and the final vulcanization is performed;
(VIII) a step of pulling the mandrel from the final vulcanized hose;
And a vulcanization temperature of the first vulcanization is lower than a vulcanization temperature of the second vulcanization.
[0012]
<2> In the production method of <1>, after the heat-resistant resin layer is extruded and coated on the outer peripheral surface of the unvulcanized hose in which the outer rubber layer is disposed in the step (IV), the step (V) 1 is a production method in which vulcanization is performed, and then the heat-resistant resin layer is peeled off and cut in the step (VI).
[0013]
<3> In the production method of <1>, after wrapping with a sheet on the outer peripheral surface of the unvulcanized hose in which the outer rubber layer is disposed in the step (IV), the first vulcanization is performed in the step (V). This is a manufacturing method in which the wrapped sheet is peeled off and then cut in the step (VI).
[0014]
<4> In the manufacturing method according to any one of <1> to <3>, the one or more reinforcing layers wound on the outer peripheral surface of the inner rubber layer in the step (III) are organic fibers or metal fibers or It is a manufacturing method which consists of a braided structure which consists of these combinations.
[0015]
<5> In the production method of <4>, the one or more reinforcing layers wound on the outer peripheral surface of the inner rubber layer in the step (III) are left and right 1 made of organic fiber, metal fiber, or a combination thereof. It is a manufacturing method which consists of a spiral structure which makes a pair.
[0016]
<6> A molded hose produced by the production method according to any one of <1> to <5>.
[0017]
According to the invention <1>, a molded hose having a stable shape free from wrinkles or cracks in the innermost resin layer can be obtained. That is, by applying the first vulcanization, the adhesive force between the innermost resin layer and the inner rubber layer is increased, and the mutual movement at the time of subsequent deformation can be suppressed to a small value, such as wrinkles of the innermost resin layer. Generation can be suppressed.
[0018]
According to the invention <2> or <3>, the rubber material is pressurized and heated by the thermal expansion of the mandrel and the molding effect by the heat-resistant resin layer or the sheet on the outer peripheral surface in the first vulcanization in the step (V), Good integration in a semi-vulcanized state. As a result, the effect of the invention <1> can be obtained more favorably.
[0019]
According to the invention <4>, particularly the invention <5>, the above-described effects can be obtained, and a molded hose excellent in pressure-proof reinforcement effect can be obtained.
[0020]
According to the invention <6>, since the resin layer on the innermost surface is free from wrinkles and cracks, the permeation amount of the refrigerant can be minimized.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
In the production method of the present invention, the elastic mandrel used in the step (I) is, for example, a steel cord placed in a core, and a vulcanized rubber, preferably ethylene propylene diene terpolymer rubber (EPDM), on the outer periphery thereof. It can be a mandrel having a vulcanized rubber made of it. The mandrel may be a thermoplastic resin such as polypropylene or polyamide. What is necessary is just to select the outer diameter of this mandrel suitably according to the internal diameter of the hose to manufacture. In the step (I), a resin layer is extruded and coated on the outer peripheral surface of the elastic mandrel. The resin layer can be a resin layer made of polyamide, polyester, polyether, polycarbonate, polyacrylate, polypropylene, polyethylene, or the like, and conventionally known ones can be appropriately selected. In the production method of the present invention, a molded hose having a stable shape without wrinkles or cracks in the resin layer on the inner surface is obtained even when the thickness of the resin layer is 700 μm or less, further 500 μm or less, more particularly 300 μm or less. be able to.
[0022]
In the step (II), an inner rubber layer is overlaid on the outer peripheral surface of the resin layer and covered by extrusion. The inner rubber layer includes butyl rubber (IIR), acrylonitrile butadiene rubber (NBR), natural rubber (NR), styrene butadiene rubber (SBR), ethylene propylene diene terpolymer rubber (EPDM), acrylic rubber (ACM). Further, rubbers such as butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), and silicone rubber can be used, but butyl rubber (IIR) is preferable in terms of airtightness. The rubber composition for hoses is appropriately blended with vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, plasticizers, softeners, fillers, etc. that are commonly used in the rubber industry. can do.
In order to improve the adhesion between the resin layer and the inner rubber layer, an adhesive is preferably applied between the two.
[0023]
In the step (III), one or more reinforcing layers are wound on the outer peripheral surface of the inner rubber layer. The reinforcing layer is preferably a braided structure made of organic fiber, metal fiber, or a combination thereof. For example, polyethylene terephthalate fiber (PET fiber) is preferably spiral (see FIG. 1) or blade ( It is knitted as shown in FIG. 2 and is disposed on the outer peripheral surface of the inner rubber layer 1. The fiber and knitting method used for the fiber reinforcing layer 3 shown in the figure are not limited and can be appropriately selected according to the intended use. Further, an adhesive rubber sheet (not shown) may be inserted between the layers wound alternately. 1 and 2, the resin layer 4 is disposed on the inner surface of the inner rubber layer.
[0024]
In the step (IV), an outer rubber layer is extruded and coated on the outer peripheral surface of the reinforcing layer. As shown in the drawing, the outer rubber layer 2 disposed on the outer peripheral surface of the fiber reinforcing layer 3 can use the same rubber material as the inner rubber layer 1, but in consideration of weather resistance, EPT, SBR / NBR A blend system or a system containing a large amount of an anti-aging agent can be used.
[0025]
In step (V), the unvulcanized hose provided with the outer rubber layer is subjected to the first vulcanization and semi-vulcanized. At this time, it is preferable to extrude and coat a heat resistant resin layer on the outer peripheral surface of the unvulcanized hose provided with the outer rubber layer in the step (IV) or to wrap a sheet. By doing in this way, a mold effect is obtained, the rubber material is heated with good pressure, and can be integrated well in a semi-vulcanized state. In addition, as a heat resistant resin layer, polymethylpentene resin is preferable and resin, such as a polypropylene and polyethylene, can also be used depending on a use. The sheet is not particularly limited as long as it has heat resistance, but a polyamide-based fiber can be suitably used. Further, pliing (drilling for escaping gas permeated through the outer rubber) can be performed on the semi-vulcanized hose by a known method.
[0026]
Here, the semi-vulcanization is obtained by setting the vulcanization temperature of the first vulcanization in the step (V) to be lower than the vulcanization temperature of the second vulcanization in the step (VII).
[0027]
In the step (VI), the semi-cured hose is cut into a predetermined length together with the elastic mandrel. When the outer peripheral surface of the outer rubber layer is covered with a heat-resistant resin layer or when the sheet is wrapped, it is cut after peeling off.
[0028]
In the step (VII), the cut semi-vulcanized hose is molded into a predetermined shape by incorporating it into a jig or a mold. At this time, since the outer heat-resistant resin coating layer or the sheet is peeled off first, it can be easily incorporated into a necessary shape. Furthermore, if preheating is performed at 130 ° C. for about 10 minutes at this time, the flexibility of the hose and mandrel is increased, and the assembly can be performed more easily, which is effective for molding into a complicated shape. Thereafter, the second vulcanization is performed and the final vulcanization is performed. The jig or die incorporating the semi-vulcanized hose can be vulcanized by placing it in a hot air vulcanizing tank as the second vulcanization. By this second vulcanization, the inner rubber layer and the outer rubber layer are completely vulcanized and the required physical properties of the rubber are obtained. Furthermore, the hose is molded into a predetermined shape by the second vulcanization.
[0029]
In the step (VIII), the mandrel is pulled out from the finally vulcanized hose. The vulcanized hose is removed from the jig or mold and the inner mandrel can be pulled out of the hose in a known manner. It is preferable to keep the drawn hose until it is completely cooled by being incorporated in a cooling mold prepared to maintain a predetermined shape. Thereby, the hose of a predetermined shape can be obtained.
[0030]
In the present invention, it goes without saying that the steps (I) to (V) may be carried out continuously, or each step may be carried out appropriately as needed. It goes without saying that the sulfur hose may be wound around a drum or the like, or steam vulcanization may be performed.
[0031]
【Example】
Hereinafter, the present invention will be described based on examples.
Example 1
In this example, a vulcanized rubber mandrel made of EPDM in which a steel cord was put in the core was used as the elastic mandrel. The outer diameter of this mandrel was 14.6 mm.
[0032]
On this mandrel, an innermost resin layer mainly composed of polyamide resin was extrusion coated with a thickness of 0.10 mm. Next, a chlorinated rubber adhesive is applied onto the polyamide resin, and an IIR rubber is extruded with a thickness of 1.2 mm as an inner rubber layer on the outer periphery. Further, 22 PET fibers 444.4 tex are provided on the outer periphery. It was wound around the spiral to make a pair alternately. IIR type 0.3 mm rubber sheets were inserted between the alternately wound layers for adhesion.
[0033]
Next, EPDM rubber was extruded and coated to a thickness of 1.2 mm on the outside of the reinforcing layer fiber layer as an outer rubber layer. These unvulcanized hoses were continuously molded, and the heat-resistant resin layer was further continuously extruded and coated on the outer periphery of the unvulcanized hoses. Polymethylpentene resin was used as the heat resistant resin layer.
[0034]
The unvulcanized hose coated with the heat-resistant resin layer was subjected to the first vulcanization by shrink-hardening the heat-resistant resin layer on the outer surface in the cooling water tank and continuously guiding it to the hot air vulcanization tank. The first vulcanization condition was 120 ° C. for 30 minutes.
[0035]
The heat-resistant resin layer was peeled off from the semi-vulcanized hose continuously covered with the heat-resistant resin layer and wound up. The hose integrated in the semi-vulcanized state was cut into a predetermined length for each mandrel and incorporated into a mold prepared so as to be a U-shape (curvature radius 60 mm).
[0036]
The mold incorporating the semi-vulcanized hose was placed in a hot-air vulcanization tank as the second vulcanization and subjected to final vulcanization. This condition was set at 150 ° C. for 60 minutes. The final vulcanized hose was taken out of the mold, the inner mandrel was pulled out from the hose by a known method, and the hose was incorporated into a cooling mold prepared so as to maintain a predetermined shape and held until it was completely cooled.
[0037]
Examples 2-6, Comparative Examples 1-4
The first vulcanization condition and the second vulcanization condition were varied as shown in Table 1 below, and various hoses were prototyped in the same manner as in Example 1 above. In Example 3, the first vulcanization condition (120 ° C. × 60 minutes) is the normal vulcanization condition (150 ° C. × 60 minutes) of the inner rubber layer and the outer rubber layer used in this hose. Thus, in the first vulcanization, the degree of vulcanization of the hose was approximately 15%.
[0038]
About the obtained hose, the following reference | standard evaluated about the shape, external appearance, and the presence or absence of the wrinkle of internal resin.

The obtained results are also shown in Table 1 below.
[0039]
[Table 1]

[0040]
From Table 1 above, the vulcanization temperature of the first vulcanization is suitably about 120 ° C. As the vulcanization conditions of the second vulcanization are approached, the inner surface resin layer is likely to wrinkle and the shape stability is also improved. You can see that it is inferior. On the other hand, if the first vulcanization is not performed (Comparative Example 1), since the rubber is completely unvulcanized, it is easy to be scratched during molding, and the outer surface layer is uneven and peeled, resulting in no commercial value. It is had.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the occurrence of wrinkles and cracks in the innermost resin layer and to obtain a molded hose having a stable shape. Therefore, it is useful as a molded hose for refrigerant transportation in an automotive air conditioning system.
[Brief description of the drawings]
FIG. 1 is a front view of a partly cutout of a molded hose according to an embodiment of the present invention.
FIG. 2 is a partially cutaway front view of a molded hose according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner rubber layer 2 Outer rubber layer 3 Fiber reinforcement layer 4 Resin layer

Claims (5)

A hose having an inner rubber layer, one or more reinforcing layers wound around the outer periphery of the inner rubber layer, and an outer rubber layer disposed on the outer periphery of the reinforcing layer, In the manufacturing method of the molded hose in which the resin layer is disposed on the inner peripheral surface,
(I) a step of extrusion coating the resin layer on the outer peripheral surface of a vulcanized rubber mandrel containing a steel cord ;
(II) a step of overlaying and extruding the inner rubber layer on the outer peripheral surface of the obtained resin layer;
(III) a step of winding one or more reinforcing layers on the outer peripheral surface of the obtained inner rubber layer;
(IV) a step of extruding and coating an outer rubber layer on the outer peripheral surface of the wound reinforcing layer;
(V) applying a first vulcanization to the unvulcanized hose provided with the outer rubber layer and semi-vulcanizing;
(VI) cutting the semi-vulcanized hose into a predetermined length together with the vulcanized rubber mandrel containing the steel cord ;
(VII) After the cut semi-vulcanized hose is molded into a predetermined shape, a second vulcanization is performed and final vulcanization is performed;
(VIII) a step of pulling the mandrel from the final vulcanized hose;
And a vulcanization temperature of the first vulcanization is lower than a vulcanization temperature of the second vulcanization.   After extruding and coating a heat resistant resin layer on the outer peripheral surface of the unvulcanized hose provided with the outer rubber layer in the step (IV), the first vulcanization is performed in the step (V), and then the heat resistance The manufacturing method according to claim 1, wherein the resin layer is peeled off and cut in the step (VI).   In the step (IV), the outer surface of the unvulcanized hose provided with the outer rubber layer is wrapped with a sheet, and then the first vulcanization is performed in the step (V), and then the wrapped sheet is peeled off to (VI) The manufacturing method of Claim 1 cut | judged in a process.   The one or more reinforcing layers wound on the outer peripheral surface of the inner rubber layer in the step (III) are made of a braided structure made of organic fibers, metal fibers, or a combination thereof. The manufacturing method according to one item.   The one or more reinforcing layers wound on the outer peripheral surface of the inner rubber layer in the step (III) are formed of a spiral structure having a pair of left and right layers made of organic fibers, metal fibers, or a combination thereof. Manufacturing method.

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