JPS621158B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a flexible composite hose in which an inner tube made of rubber and an outer tube made of thermoplastic resin are bonded via an adhesive, and more specifically, short fibers are interposed in addition to the adhesive. Accordingly, the present invention relates to a flexible composite hose in which the adhesion between the inner and outer tubes can be significantly improved by the anchoring effect of the short fibers, and a method for manufacturing the same. Conventionally, especially in flexible composite hoses that are constructed by covering an inner tube made of vulcanized rubber with an outer tube made of thermoplastic resin, adhesive bonding occurs between the vulcanized rubber layer and the thermoplastic resin layer. Various adhesives are used to impart force. However, it is not possible to obtain sufficient adhesive strength in either case, and therefore, when this type of flexible hose is bent, the rigidity or tensile elongation rate of the vulcanized rubber inner tube and thermoplastic resin outer tube, etc. Due to the difference in
As shown in b, there is delamination A at the bending part S.
or wrinkles B. At present, this phenomenon continues to grow as the folding process is repeated, causing problems such as breakage at the wrinkled area. The present invention was made in view of the above-mentioned current situation, and
It is an object of the present invention to provide a flexible composite hose that solves the above-mentioned problems all at once, and a method for manufacturing the same. The feature is that by joining the thermoplastic resin outer tube to the rubber inner tube through adhesive and short fibers, the adhesion of the inner and outer tubes is improved by the anchoring effect of the short fibers. This is a significant improvement. The present invention will be explained below by way of examples with reference to the drawings. First, to explain the flexible composite hose according to the present invention, as shown in FIGS. 2 to 4, an inner tube 1 made of rubber, particularly an inner tube 1 made of vulcanized rubber, and an outer tube 2 made of thermoplastic resin are attached. It is constructed by joining via an adhesive 3 and short fibers 4. Note that 5 in the figure is a surface treatment layer applied to the surface of the inner tube 1. This surface treatment layer 5 is a treatment for improving the adhesiveness of the surface of the inner tube 1, for example,
Surface treatments such as oxidative thermal decomposition and desulfurization of the rubber surface can be carried out using oxidizing agents, flame treatment, electrical discharge machining, etc., or surface treatment agents for vulcanized rubber that are simple and highly effective in imparting adhesive strength, such as Aftreat (Zeon Kosan) Co., Ltd.) or coated with it. The adhesive 3 applied to the surface of the inner tube 1 made of vulcanized rubber may be, for example, a solvent-based adhesive based on chloroprene-phenol resin, a solvent-based adhesive made of thermoplastic urethane, an isocyanate and amine, or a polyol. An equireactive urethane adhesive, an epoxy resin adhesive, or the like that has good adhesive strength not only for the rubber inner tube 1 but also for the short fibers 4 is used. The short fibers 4 include natural fibers, synthetic fibers,
Metal fibers, inorganic fibers, etc. cut into fiber lengths of 0.5 to 10 mm are preferable, and organic short fibers such as rayon, vinylon, polyamide, and polyester, carbon fibers, and short glass fibers are particularly preferable. When adhering the short fibers 4 to the adhesive 3 applied to the surface of the inner tube 1, as shown in FIG. Alternatively, by squeezing the randomly fluffed short fibers with a rotating rubber die, the short fibers 4 may be oriented in one direction as shown in FIG. In addition, when selecting the material of the short fibers 4, special attention must be paid to its melting temperature. That is, the melting temperature of the short fibers 4 needs to be sufficiently higher than the processing temperature at the time of coating the outer tube 2 made of thermoplastic resin. If the melting temperature of the short fibers 4 is lower than the processing temperature, the short fibers will melt when the outer tube 2 is melted and coated, and the short fibers 4 will become the fourth
This is because, as shown in the figure, it does not cut into the inner circumferential surface of the outer tube 2, making it impossible to obtain an anchoring effect. Next, a method of manufacturing the above-described flexible composite hose will be explained. A vulcanized rubber inner tube is used as the rubber inner tube 1, and in this embodiment, the vulcanized rubber inner tube is first subjected to surface treatment by the above-mentioned means to improve its adhesion. An adhesive 3 is applied to the surface of the surface treatment layer 5, short fibers 4 are sprinkled onto the adhesive 3 to make it adhere, and then a thermoplastic resin is melted using a plastic extruder (not shown). The present flexible composite hose can be obtained by covering the outer tube 2 with the outer tube 2. As mentioned above, some of the short fibers 4 sprinkled on the outer peripheral surface of the adhesive 3 and bonded in a fluffy state pierce the molten thermoplastic resin layer as shown in FIG. 4, and due to this anchoring effect, The inner tube 1 and the outer tube 2 are integrally joined together with the adhesive force of the adhesive 3. Therefore, in the flexible composite hose obtained by the above method, even if the inner tube 1 and the outer tube 2 have different rigidities and tensile elongation rates, when the hose is bent, the short fibers 4 have no anchoring effect. Therefore, the outer tube 2 can be restrained from sagging, and separation between the inner tube 1 and the outer tube 2 can be prevented. Note that the inner tube 1 is made of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber,
Materials such as nitrile rubber and ethylene propylene rubber that are flexible and can be easily tube-formed and vulcanized by conventional means are good, and tubes made of different materials can be vulcanized and joined together. A tube may be used, and an inner tube with a reinforcing cord layer provided therein may also be used. Next, the adhesion strength between the inner and outer tubes of the flexible composite hose according to the present invention and the conventional hose will be compared using specific examples as follows. Example 1 Styrene and butadiene rubber was extruded into a tube shape (inner diameter 9.5 x outer diameter 14.0), heated and vulcanized, and then
The outer surface is coated by dipping in Aftreat (manufactured by Zeon Kosan Co., Ltd.), and after drying, a chloroprene-phenol resin solvent-based adhesive such as Hamatite A-862 (manufactured by Yokohama Rubber Co., Ltd.) is applied. Sprinkle short fibers (3mm length) and adhere. The plastic extruder is equipped with a coating die to produce polyolefin elastomers such as the Sumitomo TPE1900.
An outer tube was formed by coating the outer surface of the inner tube with staple fibers (manufactured by Sumitomo Chemical Co., Ltd.) by 1.5 mm onto the outer surface of the inner tube. Comparative Example 1 Sumitomo TPE1900 was directly coated on the outer surface of the vulcanized rubber inner tube of Example 1 to compare the adhesive properties of the inner tube and outer tube. Comparative Example 2 To compare the adhesive properties of the inner and outer tubes, the vulcanized rubber of Example 1 was coated with adhesive A-862 after surface treatment, and the outer surface was coated with Sumitomo TPE1900. Example 2 The vulcanized rubber inner tube of Example 1 was treated with aftrete and Vylon 30P (manufactured by Toyobo Co., Ltd.) was used as an adhesive.
and Coronate L [manufactured by Nippon Polyurethane Co., Ltd.] 100
After dipping the solution into a solvent solution and applying it to the rubber inner tube, sprinkle it with tire cord scraps and apply heat bonding. Using a plastic extruder, the outer surface of the inner tube to which short fibers were adhered was coated with 1.5 mm of Pelprene P-70-B (Toyobo Co., Ltd.) as a thermoplastic elastomer to form an outer tube. Comparative Example 3 In order to compare the adhesive properties of the inner tube and outer tube, the outer surface of the vulcanized rubber inner tube of Example 1 was directly coated with Pelprene P-70-B. Comparative Example 4 To compare the adhesion of the inner and outer tubes, the vulcanized rubber inner tube of Example 1 was surface-treated and then coated with Vyron adhesive in the same manner as in Example 2, and the outer surface was coated with Pelprene P-70. did. Each of the above-mentioned examples and comparative examples is
The results of a peel test conducted using the peel test method according to 6301-7(4) are summarized in the table below.

【table】

[Table] As is clear from this table, each flexible composite hose of the present invention has significantly higher adhesion strength between the inner and outer tubes than the conventional hoses. As described above, since the outer tube made of thermoplastic resin is bonded to the inner tube made of rubber via adhesive and short fibers, the adhesion between the inner and outer tubes is controlled by the anchoring effect of the short fibers. can be significantly improved. Therefore, even if the product is repeatedly bent, no delamination or wrinkles will occur between the layers of the inner tube and the outer tube, and the life of the product can be significantly extended.

[Brief explanation of the drawing]

Figures 1a and 1b are explanatory diagrams showing how delamination and wrinkles occur at the bent portion when a conventional flexible composite hose is bent, and Figures 2 to 4 show examples of the present invention. FIGS. 2 and 3 are partially cutaway perspective views, respectively, and FIG. 4 is an explanatory diagram illustrating the anchoring effect of short fibers. 1... Inner tube, 2... Outer tube, 3... Adhesive, 4... Short fiber.

Claims (1)

[Claims] 1. An inner tube made of rubber and an outer tube made of thermoplastic resin,
A flexible composite hose characterized by being bonded via an adhesive and short fibers. 2 After applying adhesive to the surface of the rubber inner tube,
A method for producing a flexible composite hose, which comprises adhering short fibers to the adhesive and then covering them with a thermoplastic resin.