JPH10100160A - Mandrel for producing hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mandrel for producing a hose, pref., a rubber hose, especially, excellent in the releasability from the rubber hose immediately after vulcanization, avoided from the shift and peeling of a coating layer caused by the shearing stress generated when the mandrel is pulled out of the rubber hose immediately after vulcanization, capable of withstanding long-term use and having high rigidity under high temp. SOLUTION: In a mandrel for producing a hose wherein a rod-shaped core material composed of a resin with an m.p. of 180 deg.C or higher and thermal deforming temp. (a value measured under load of 4.6 kg/cm<2> according to ASTM D-648) of 150 deg.C or higher is coated with a resin layer with a thickness of 1mm or more composed of 4-methyl-1-penten polymer, a means preventing the shift peeling of the core material and the coating layer caused by shearing stress inevitably acting on the mandrel at a time of use is provided between the surface of the core material of the mandrel and the coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mandrel useful for manufacturing hoses, particularly for manufacturing rubber hoses.
More specifically, it is excellent in use durability and 4-methyl-
The present invention relates to a mandrel for manufacturing hoses, which retains excellent heat resistance and releasability, which are the characteristics of 1-pentene polymers, and has improved drawbacks such as low rigidity at high temperatures.

[0002]

2. Description of the Prior Art Mandrel materials used in the manufacture of hoses, especially rubber hoses, generally include 4-methyl-1.
-Penten polymers, nylon, EPDM and the like are used. Since 4-methyl-1-pentene polymer has the lowest surface tension next to fluororesin, a mandrel made of 4-methyl-1-pentene polymer is easy to separate from a rubber hose after vulcanizing the rubber hose. have. However, this polymer has a high melting point, but does not always have high rigidity at high temperatures. Therefore, when tension is applied during vulcanization of a rubber hose, there is a drawback that inconveniences such as expansion and deformation of the mandrel are often caused. On the other hand, a nylon mandrel has high rigidity even at high temperatures, and has little deformation due to tension or the like at the time of vulcanization of a rubber hose, but has a disadvantage that it is difficult to remove from a hose because of its high surface tension. Further, in order to improve the disadvantages of the above-mentioned two mandrels and to provide both releasability and high rigidity at high temperatures, nylon having excellent rigidity at high temperatures is used as a core material and the surface thereof is 4-methyl-1-. Attempts were made to coat with a pentene polymer, but the 4-methyl-1-pentene polymer did not have sufficient adhesive strength with the core nylon due to its high mold release properties.
For example, in the process of manufacturing a rubber hose using a mandrel, after vulcanizing rubber, when pulling out the mandrel from the rubber hose immediately after the vulcanization, the shear force inevitably generated toward the center of the mandrel is generated. Due to the displacement stress generated between the core material and the coating layer, peeling of the coating layer occurs,
A practical mandrel that can withstand repeated use cannot be obtained.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rubber hose, particularly a rubber hose, which has excellent releasability from a rubber hose immediately after vulcanization, and is produced when a mandrel is pulled out from a rubber hose immediately after vulcanization. It is an object of the present invention to provide a mandrel for manufacturing a hose that avoids displacement and peeling of a coating layer due to displacement stress, withstands long-term use, and has high rigidity at high temperatures.

[0004]

According to the present invention, a melting point of 1 is provided.
A rod-shaped core made of a resin having a heat deformation temperature of 80 ° C or more and a heat deformation temperature (measured under a load of 4.6 kg / cm ² in accordance with ASTM D-648) of 150 ° C or more, made of a 4-methyl-1-pentene polymer. In a mandrel for manufacturing a hose in which a resin layer is coated with a thickness of 1 mm or more, a core material caused by shear stress inevitably acting on the mandrel at the time of use between a mandrel core surface and a coating layer. There is provided a mandrel for manufacturing a hose excellent in use durability, which is provided with a means for preventing separation from the coating layer.

According to the present invention, as one mode of the mandrel for manufacturing a hose of the present invention, a means for preventing the core material and the coating layer from being separated from each other is provided by means of unevenness or a step formed on the surface of the rod-shaped core material. And the depth of the irregularities or steps is 50
A mandrel for manufacturing a hose is provided, which has a diameter of 0 μm or more and has an average frequency of 1 or more per 10 cm in the core material length direction.

Further, as another aspect of the mandrel for manufacturing a hose according to the present invention, the slip-off preventing means is provided with a core-forming resin and a coating layer provided between the surface of the rod-shaped core material and the coating layer. A mandrel for manufacturing a hose, which is an adhesive material having an affinity for both resins.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the 4-methyl-1-pentene polymer used for coating the surface of the core material may be a homopolymer of 4-methyl-1-pentene or 4-methyl-1-pentene. -1-pentene and other α-olefins,
For example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene,
And copolymers with α-olefins having 2 to 20 carbon atoms such as eicosene. Preferred copolymerization components are 1-decene, 1-dodecene, 1-tetradecene,
-Hexadecene, 1-octadecene, 1-eicosene. Of course, two or more of these α-olefins may be used.

When the above-mentioned copolymer is used as the 4-methyl-1-pentene polymer, the content of the copolymer component is 0.1.
It is preferable from 1 to less than 20% by weight from the viewpoint of heat resistance.

The melt flow rate (MFR) of such a 4-methyl-1-pentene polymer is determined according to ASTM D.
The value measured under the conditions of a load of 5.0 kg and a temperature of 260 ° C. according to -1238 is preferably in the range of 0.1 to 200 g / 10 min, and more preferably in the range of 1.0 to 150 g / 10 min. Particularly preferred.

[0010] The resin for coating the core material comprising the 4-methyl-1-pentene polymer of the present invention includes a softener, a weather resistance stabilizer,
Various additives, such as heat stabilizers, slip agents, nucleating agents, pigments, and dyes, which are usually used in addition to polyolefins, may be added as long as the object of the present invention is not impaired.

The resin forming the core material of the mandrel of the present invention has a melting point of 180 ° C. or more, preferably 200 ° C. or more, and a load of 4.6 kg / c according to ASTM D-648.
A high melting point and heat deformable resin having a heat deformation temperature of 150 ° C. or more measured in m ² is used. More specifically, as such a resin, for example, nylon-6 or nylon having the above melting point and heat deformation temperature is used. 6, 6, Nylon-6, 12, Nylon-4, 6, etc., aliphatic polyamides, poly (hexamethylene terephthalamide), poly (hexamethylene terephthalamide / isophthalamide), poly (paraphenylene terephthalamide), etc. Polyamide resin such as aromatic polyamide, polyethylene terephthalate, polybutylene terephthalate, or isophthalic acid, 1,
Examples include polyester resins such as polymers co-condensed with 4-cyclohexanedimethanol and the like, polyphenylene oxide resins and the like, and fiber reinforced products of these resins.

A resin having a melting point and a heat distortion temperature lower than the above-mentioned melting point and heat deformation temperature specified in the present invention is difficult to be melt-coated as a preferable coating method when coating the resin for coating of the present invention. Coating by other methods, such as solution method,
Even when a mandrel is manufactured, it is not preferable because it undergoes large thermal deformation, and further softens or melts in an extreme case when used at a high temperature such as a rubber vulcanizing step.

In the present invention, the means for preventing displacement provided between the rod-shaped core material and the coating resin layer include, for example, (i) providing irregularities or steps on the surface of the core material. (Ii) An adhesive material having an affinity for both the core material forming resin and the coating layer forming resin is bonded as an intermediate layer. And the like.

As the means (i), specifically, the high melting point and heat-resistant deformable resin of the present invention is formed into a rod shape, and the surface thereof has a depth of 500 μm or more with respect to the center axis direction of the rod shape. An average of at least one asperity or step per 10 cm in the length direction, preferably at least five, particularly preferably one or more.
Means in which zero or more pieces are used as a core material can be given. It is preferable that there be at least one unevenness or step per 10 cm, that is, at least one at every 10 cm, particularly from the viewpoint of preventing peeling of the coating layer and durability of the mandrel. By providing such irregularities or steps on the surface of the core material, the coating strength of the resin layer made of the 4-methyl-1-pentene polymer that covers the core material is further improved, and the deformation stress during use of the mandrel is increased. Even if it receives, there is no problem such as delamination. In addition,
The height difference between the irregularities and the steps can be measured, for example, using a surface roughness meter. Further, the number of irregularities or steps can be counted by visual observation, tactile sensation, electron microscope, or the like.

The unevenness or the step is preferably such that the depth, that is, the height difference between the highest and lowest parts is 500 μm or more, and if the height difference is 500 μm or less, the coating layer is peeled off when the displacement stress is large. Then, in an extreme case, the coating layer may come off from the core material. The same inconvenience occurs when the number of irregularities or steps is smaller than the above-mentioned specification.

The method of providing irregularities or steps on the rod-shaped body as the core material is not necessarily limited to this. For example, the resin is coated on the surface by using a die having a normal extrusion cross section. After extruding as a smooth round bar, a method of shaving the surface to provide a step, a method of sandblasting to roughen the surface, a method of causing melt fracture at the time of extrusion to roughen the surface, and the like can be exemplified.

In the present invention, the above-mentioned core material is
-A resin comprising a methyl-1-pentene polymer is coated. As a method of coating the resin, a melt coating method in which the resin is melted and the molten resin is extrusion-coated on a core material using an extruder or the like,
Alternatively, various methods such as a solution coating method in which a resin solution is prepared and the core material is doped into the resin solution, or the resin solution is coated on the core material by coating or the like can be used. Is preferred.

The thickness of the resin coating layer needs to be 1 mm or more, and is preferably in the range of 2 mm to 10 mm. When the thickness of the coating layer is less than 1 mm, the coating layer is liable to peel off, and in a long-term use, the resin layer is partially worn out and damaged. Furthermore, the excellent releasability, which is a characteristic of the 4-methyl-1-pentene polymer, cannot be sufficiently exhibited. Regarding the relationship between the outer diameter of the mandrel and the thickness of the coating layer, the ratio of coating layer thickness / outer diameter is 0.02 to 0.5, preferably 0.05 to 0.4, more preferably 0.10 to 0.30 is desirable from the viewpoint of the balance between heat resistance and peeling properties.

As the adhesive material used in the means (ii), various adhesives having adhesive properties to both the core resin and the coating resin can be used without particular limitation. It is preferable to use the trade name “Admer” manufactured by Petrochemical Industry Co., Ltd. In the present invention, the means (i) is particularly preferable as the means for preventing displacement, because the molding is easy and the coating layer is less likely to peel off when the mandrel is pulled out. The mandrel of the present invention
Although it is also used for producing resin hoses, it can be suitably used particularly as a mandrel for producing rubber hoses such as water hoses, steam hoses and air hoses.

Hereinafter, the present invention will be described more specifically with reference to examples.

EXAMPLES The mandrels shown in the following examples were manufactured under the following conditions. The methods for measuring the physical properties and performance measured in the examples were as follows.

(1) Manufacture of the core material The core material was formed into a rod using a die having a circular extruded cross section with a 45 mm extruder (set temperature: 280 ° C.), and grooves were formed on the surface of the rod. Was. (2) Preparation of Mandrel A 4-methyl-1-pentene polymer was placed on the above-mentioned core material.
It was extruded and coated with a 5 mm extruder (set temperature: 280 ° C.).

(3) Evaluation of Physical Properties A creep test of the mandrel was performed under the conditions of a high-temperature creep load of 20 kg / cm ² and 140 ° C., and the time until breaking was measured. Mandrel removal pressure After covering 10 m of the mandrel with rubber and vulcanizing, water pressure was applied to one end of the mandrel, and the pressure at which the mandrel was released was measured.

(Example 1) Nylon 6, A1080BR
L (manufactured by Unitika Ltd., HDT (heat distortion temperature): 174
℃, MFR (melt flow rate): 15) 45 mm
Extruder (set temperature: 280 ° C) with a cross section of 7m in diameter
extruded through a circular die having a diameter of 7 mm to form a rod having a diameter of 7 mm.
20 and 10 grooves of 1.0 mm width were formed at equal intervals per 10 cm of the rod-shaped body. Next, 4-methyl-1-
A pentene polymer MX004 (manufactured by Mitsui Petrochemical Industries, Ltd., MFR: 23) was extrusion-coated with a 45 mm extruder (set temperature: 280 ° C.) to produce a mandrel having an outer diameter of 9 mm. The high-temperature creep and mandrel release pressure of this mandrel were measured. Table 1 shows the results.

Example 2 Polyethylene terephthalate
G, J140 (manufactured by Mitsui Petrochemical Industries, Ltd., HDT: 1)
55 ° C., intrinsic viscosity: 1.0) was extruded with a 45 mm extruder (setting temperature: 280 ° C.) through a circular die having a cross section of 7 mm in diameter to form a rod having a diameter of 7 mm. Heat at 4 ° C. for 4 hours to crystallize.
The surface of this rod was shaved to a depth of 500 μm and a width of 1.0
20 mm grooves were formed at equal intervals per 10 cm of the rod. Next, a 4-methyl-1-pentene polymer MX004 (manufactured by Mitsui Petrochemical Industries, Ltd., MF
R: 23) with a 45 mm extruder (set temperature: 280 ° C.)
To form a mandrel having an outer diameter of 9 mm. The high-temperature creep and mandrel release pressure of this mandrel were measured. Table 1 shows the results.

(Comparative Example 1) 4-Methyl-1-pentene polymer MX004 (manufactured by Mitsui Petrochemical Industries, Ltd., HD
T: 80 ° C., MFR: 23) was extruded with a 45 mm extruder (setting temperature: 280 ° C.) through a circular die having a diameter of 9 mm to form a mandrel having a diameter of 9 mm.
The high-temperature creep and mandrel release pressure of this mandrel were measured. Table 1 shows the results.

(Comparative Example 2) Nylon 6, A1080BR
L (manufactured by Unitika Ltd., MFR: 15) was extruded with a 45 mm extruder (set temperature: 280 ° C.) through a circular die having a cross section of 7 mm in diameter, to prepare a rod having a diameter of 7 mm. Next, a 4-methyl-1-pentene polymer MX004 (manufactured by Mitsui Petrochemical Industries, Ltd., MF
R: 23) with a 45 mm extruder (set temperature: 280 ° C.)
To form a mandrel having an outer diameter of 9 mm. The high-temperature creep and mandrel release pressure of this mandrel were measured. Table 1 shows the results.

(Comparative Example 3) Nylon 6, A1080BR
L (manufactured by Unitika Ltd., MFR: 15) was extruded with a 45 mm extruder (set temperature: 280 ° C.) to have a cross section of 9 mm in diameter
To make a 9 mm diameter mandrel. The high-temperature creep and mandrel release pressure of this mandrel were measured. Table 1 shows the results.

[0028]

[Table 1]

[0029]

The hose mandrel of the present invention has good releasability from hoses, particularly rubber hoses, and excellent rigidity at high temperatures, and is useful for vulcanizing rubber hoses. In particular, when a rubber hose including a mandrel is subjected to tension in the vulcanization step, the mandrel is hardly deformed, such as being elongated by the tension, and is excellent in use durability.

Claims (5)

[Claims] 1. A material having a melting point of 180 ° C. or higher and a heat distortion temperature (AST)
(Measured under a load of 4.6 kg / cm ² according to MD-648) Resin layer made of 4-methyl-1-pentene polymer on a rod-shaped core made of resin at 150 ° C. or more with thickness of 1 mm or more In the mandrel for manufacturing a hose coated with the above, between the surface of the mandrel core and the layer between the mandrel and the coating layer, the slip between the core material and the coating layer caused by the shear stress inevitably acting on the mandrel during use is prevented. A mandrel for manufacturing a hose excellent in use durability, characterized in that the mandrel is provided with a means for performing. 2. The method according to claim 1, wherein the means for preventing the displacement and peeling are irregularities or steps formed on the surface of the rod-shaped core material, and the depth of the irregularities or steps is 500 μm or more, and the frequency of formation is about 10 cm in the core material length direction. The mandrel for producing a hose according to claim 1, wherein the number is one or more on average. 3. The method according to claim 1, wherein the slip-off prevention means is an adhesive material having an affinity for both a core material forming resin and a coating layer resin provided between the surface of the rod-shaped core material and the coating layer.
The described mandrel for hose manufacture. 4. The resin layer comprising the 4-methyl-1-pentene polymer has 4-methyl-1-pentene units as 8 units.
The mandrel according to any one of claims 1 to 3, which is a resin layer comprising a random copolymer of 4-methyl-1-pentene containing 0% by weight or more and an α-olefin having 2 to 20 carbon atoms. 5. The resin layer comprising the 4-methyl-1-pentene polymer is made of 4-methyl-1-pentene and 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. The mandrel according to claim 4, which is a resin layer comprising a random copolymer with at least one selected α-olefin.