JPS6018903Y2 - Core for hose manufacturing - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a core for manufacturing hoses.

Conventionally, plastic cores made of crosslinked polyethylene, polypropylene, nylon, polyester, etc. have been used.

In the production of hoses using plastic cores, for example, unvulcanized rubber or plastics are extruded onto the core,
Next, the unvulcanized rubber and plastic layers on the core are heated and vulcanized, then cooled, and finally the plastic core is pulled out.

However, conventionally used plastic cores have various drawbacks and are not necessarily satisfactory.

For example, nylon cores and polyester cores have extremely high water absorption rates, so their outer diameters increase due to water absorption, or when heated to high temperatures during vulcanization, they release absorbed moisture, resulting in vulcanized rubber, plastic layers ( This causes problems such as making the inner diameter of the hose body non-uniform and forming voids within the layer.

Therefore, it is necessary to heat and dry it before use.

Furthermore, since these cores are hydrolyzed by water and their surfaces gradually become rough, their lifespan after repeated use is extremely short.

On the other hand, crosslinked polyethylene cores and polypropylene cores have poor high-temperature dimensional stability and therefore often deform when heated to vulcanization temperatures.

In view of the above, the present invention proposes a novel hose manufacturing core that does not have the drawbacks seen in conventional plastic cores, that is, a core made of poly-4-methylpentene-1 and consisting of an elongated body with a desired cross-sectional shape. It is something.

As poly-4-methylpentene-1, 4-methylpentene-1 homopolymers and copolymers are used.

Examples of such polymers include ASTM D 1238
-70 (260℃? 5kg) It is a crystalline polymer with a melt index of 1 to 10, especially 5 to 80, and a stereoregularity with a density of 0.82 to 0.8 at 23℃. .

Poly-4-methylpentene-1 is produced by polymerizing 4-methylpentene-1 alone or together with copolymerization components described below using a Ziegler type catalyst.

Copolymerization components include ethylene, propylene, butene,
Pentene, hexene, octene, 3-methyl-butene-
1,3-methyl-pentene-1,4,4'-dimethyl-
Straight chain or branched aliphatic hydrocarbon vinyl compounds such as pentene-1,3-methyl-hexene-1, styrene, orthodivinylbenzene, metadivinylbenzene, paradivinylbenzene, metadivinyltoluene, varadivinyltoluene, α-methyl Examples include aromatic hydrocarbon vinyl compounds such as styrene.

One type of copolymerization component may be used, or two or more types may be used.

The poly-4-methylpentene-1 used in the present invention preferably contains at least 6% of 4-methylpentene-1.

Also preferred is one containing 0.1 to 20% by weight of an aromatic hydrocarbon vinyl compound component.

Apart from the above-mentioned poly-4-methylpentene-1 and its copolymer, a compatible polymer or liquid may be added as a plasticizer in order to give them further flexibility.

The amount added is preferably 3% by volume or less, since the high-temperature shape retention of poly-4-methylpentene-1 must be maintained.

Particularly preferred plasticizers have a molecular weight of 300 to 5°000.
-Olefin oligomers and polybutenes.

Furthermore, it is also possible to add a small amount of oxidation stabilizer or the like in order to extend the service life of the core.

The attached drawing is a partial perspective view of an embodiment of the present invention, in which 1 is the main body of a core for manufacturing a hose made of the above-mentioned poly-4-methylpentene-1 and has a circular cross section; It is a reinforcing body made of a twisted wire or a single wire made of metal such as iron, steel, aluminum, copper, etc.

The cross-sectional shape of the core may be circular, elliptical, or any other shape depending on the cross-sectional shape of the hose desired to be manufactured.

This embodiment is produced - for example, by extrusion coating poly-4-methylpentene-1 onto the reinforcing body 2.

After the vulcanization process, the core is pulled out, but the longer the hose manufactured, the greater the force required to pull it out, even if a lubricant or release agent is applied to the core surface. Since there is a possibility that the core may be cut, it is preferable in the present invention that the reinforcing body 2 is built in.

In particular, incorporating twisted wires is preferable because it hardly changes the flexibility of the core.

However, such a reinforcing member is not necessary when the core is not under tension, such as when applying water pressure to one end of the hose and extruding and separating the core by the water pressure, without drawing it out.

The table below shows nylon and typical poly-4-methylpentene.
Compare the physical properties with 1.

A: Poly-4-methylpentene, manufactured by Mitsui Petrochemicals.
1 (Product name TPX MX-004) B: Poly-4-methylpentene, manufactured by Mitsui Petrochemical Co., Ltd.
l (Product name: TRXMx-〇〇1) C: 6 parts by weight of α-olefin oligomer (Lipo Roof 70 manufactured by Lion Oil and Fat) was added to 0 parts by weight of the above.

D: Nylon 6, manufactured by Toshisha Co., Ltd. CM 1021 From the above table, poly-4-methylpentene-1 has a high melting point equal to or higher than that of nylon, so it can withstand vulcanization at the same high temperatures as conventional ones, and is resistant to heat deterioration. It is clear that it has excellent properties and has a long service life.

Furthermore, the water absorption rate is 0.01% compared to 1.9% for nylon.
It has the great advantage of being small and can therefore be used undried.

A, B or C of poly-4-methylpentene-l shown above was placed on seven twisted soft iron wires with an outer diameter of 0.5 m.
each with an outer diameter of 10.
Using the core of each example of Ormn, a natural rubber composition containing 3 parts by weight of sulfur was extruded onto the core to a thickness of 10 mm, a canvas tape was wound thereon, and then heated at 180°C with steam.
, 2 to vulcanize the rubber layer.

After cooling, the core was pulled out to produce each vacuum vulcanized rubber hose.

Each of the above cores used in this production had been left in the air for about a week before use, and was used as is without drying.
No raw skin voids or abnormalities in the inner diameter were observed in each of the obtained rubber hoses.

Moreover, the tensile strength and elongation of poly-4-methylpentene-1 of each core after one use were not different from the initial values.

[Brief explanation of the drawing]

The accompanying drawing is a perspective view of an embodiment of the present invention, in which 1 is the main body of the core for manufacturing a hose, and 2 is a reinforcing body.

Claims (1)

[Claims for Utility Model Registration] 1. A core for manufacturing a hose, characterized in that it is a long body made of poly-4-methylpentene-1 and having a desired cross-sectional shape. 2. The core for manufacturing a hose according to claim 1, wherein the poly-4-methylpentene-1 is a homopolymer of 4-methylpentene-1. 3. The core for manufacturing a hose according to claim 1, wherein the poly-4-methylpentene-1 is a copolymer of 4-methylpentene-■ and other copolymer components. 4. The core for manufacturing a hose according to claim 3, wherein the poly-4-methylpentene-1 is a copolymer containing at least 6% by weight of 4-methylpentene-1. 5. The core for manufacturing a hose according to any one of claims 1 to 4, wherein the poly-4-methylpentene-1 contains a plasticizer in an amount of 3% by weight or less. 6. The core for manufacturing a hose according to any one of claims 1 to 5, wherein the poly-4-methylpentene-1 has a built-in reinforcing body.