JP3118024B2 - Manufacturing method of insulating tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an insulating tube comprising a braided sleeve and silicone rubber, which is used for, for example, insulating protection of a lead wire of a motor.

[0002]

2. Description of the Related Art Conventionally, as an insulating protective tube, one obtained by applying an alkyd varnish to a braided sleeve of an organic fiber such as polyester four times has been used. As a method for producing these, the viscosity at 25 ° C. is 0.1 Pa ·
By dipping the braided sleeve four times in a solution of alkyd resin diluted to about s, and drying each time. This will be described in more detail with reference to the drawings. FIG. 3 is a schematic view showing an example of an apparatus for performing a conventional manufacturing method. Using the apparatus shown in FIG. 3, the braided sleeve 31 supplied at a linear velocity of 45 m / h was adjusted to have a viscosity at 25 ° C. of 0.1
Immersed in an alkyd resin solution 32 adjusted to Pa · S,
Thereafter, drying and curing are performed in a drying furnace 33 for 10 minutes. As shown in FIG. 3, this is continuously performed four times to produce an insulating tube.

[0003] Recently, a silicone varnish coated on a braided sleeve made of an organic fiber is also used. This production method also has a viscosity at 25 ° C. of 0.1 P
By dipping the braided sleeve into silicone varnish diluted to about a · s four times and drying each time. Incidentally, even in the case of the silicone varnish, the linear speed and the drying and curing time of the braided sleeve are the same as those of the alkyd varnish.

[0004]

However, although the insulating tube formed by applying the alkyd varnish has the advantage of being inexpensive, it does not have a stable withstand voltage characteristic and has flexibility at a low temperature of about 0 ° C. There is a drawback that handling is difficult because it is extremely poor. An insulating tube formed by applying a silicone varnish is excellent in withstand voltage characteristics and flexibility at low temperatures, but has a disadvantage that it is expensive.

In view of the above problems, the present inventors have conducted various studies on a manufacturing method capable of providing an insulated tube having excellent withstand voltage characteristics and excellent flexibility even at low temperatures without losing flexibility. Reached.

[0006]

The method for manufacturing an insulating tube according to the present invention comprises the following steps: (1) A method for manufacturing an insulating tube comprising a braided sleeve made of fiber and silicone rubber, wherein the braided sleeve is Viscosity at 25 ° C of 5 Pa · s or more and 100 Pa · s between the die having the liquid passing means and the sleeve introduction nozzle
Less than silicone rubber is contacted and shaped at the top opening of the die. (2) In the method of manufacturing an insulating tube according to (1),
Immediately before contacting a silicone rubber having a viscosity of 5 Pa · s or more and less than 100 Pa · s at 25 ° C., a primer containing at least titanate diluted with a solvent that easily evaporates is applied to the braided sleeve and dried. The above is characterized.

Here, as the braided sleeve formed of fiber, terephthalate polyester having good heat resistance,
Fibers such as wholly aromatic polyesters, aliphatic polyamides, and aromatic polyamides are braided by a known method to form a sleeve.

[0008] A primer is needed to adhere the braided sleeve formed of fibers to the silicone rubber. In the present invention, those containing titanate as at least one component are used. Those containing no titanate are not preferred because of poor adhesion and long drying time. Such primers are commercially available from various companies and may be used. When used, it is diluted to about 3 to 40% with a solvent that evaporates easily. As the solvent that evaporates easily, hydrocarbons and aliphatic esters having a boiling point of 110 ° C. or less are preferably used.

[0009] Silicone rubber has a viscosity of 5 at 25 ° C.
It is necessary to be Pa · s or more and less than 100 Pa · s. When the viscosity is lower than 5 Pa · s, it is not preferable because a single application does not provide a sufficient thickness, and when the viscosity exceeds 100 Pa · s, the braided sleeve is disadvantageously deformed. As is known, the viscosity is adjusted by adjusting the molecular weight of the base polysiloxane and the amount of the filler. As the curing agent, a platinum vulcanization system which is less likely to cause foaming or the like is preferably employed.

Next, the production method of the present invention will be described in more detail. FIG. 1 is an example of a manufacturing apparatus for performing the manufacturing method of the present invention. The braided sleeve has a linear speed of 150 to
It is pulled out through, for example, a tensioner or the like so as not to apply an excessive tension at 300 m / h, and first, a primer is applied. As a method of applying the primer, a method such as dipping a braided sleeve into a solution or spraying a solution onto the braided sleeve is used, but dip is preferred. Subsequently, the dilution solvent of the primer is dried in a drying furnace. The condition of the drying furnace depends on the dilution solvent,
Do not exceed 200 ° C.

[0011] After the primer is applied and dried, the braided sleeve is guided to a silicone rubber coating mechanism immediately to avoid dirt and deterioration and to simplify the process, and is coated with silicone rubber. FIG. 2 shows an example of the silicone rubber application mechanism. When the mechanism shown in FIG. 2 is used, the silicone rubber is kept at a certain level in the silicone rubber tank, and has penetrated to the inside of the die by means of liquid passing through the die. The braided sleeve and the silicone rubber that have passed through the nozzle come into contact inside the die, and the outer diameter is controlled by the opening at the top of the die. Other mechanisms may be used as long as the mechanism can apply the silicone rubber and control the outer diameter by applying no pressure or applying slight pressure even if it is applied.

[0012] The braided sleeve coated with silicone rubber is then led to a curing furnace and cured by heating at a temperature not exceeding 250 ° C to form an insulating tube by one application.
It is wound by a winding roll.

[0013]

According to the present invention, a braided sleeve made of fiber has a viscosity of 5 Pa · s or more and 100 Pa · s at 25 ° C.
By applying silicone rubber of less than s and shaping with a die and a nozzle, an insulating tube having excellent withstand voltage characteristics and excellent flexibility without losing flexibility even at low temperatures can be manufactured with high productivity. In addition, immediately before contacting a silicone rubber having a viscosity of 5 Pa · s or more and less than 100 Pa · s at 25 ° C., by applying and drying a primer containing at least titanate diluted to a solvent that easily evaporates to the braided sleeve, as one component. Thus, the braided sleeve and the silicone rubber can be firmly bonded.

[0014]

The present invention will be described in more detail with reference to the following examples. In this example, polyethylene terephthalate fiber was selected as the fiber, and a braided sleeve having an inner diameter of 9 mm was used. As the primer, a mixture of X primer and Y primer (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd.) containing at least titanate as a component is selected, and further diluted with heptane to obtain a solid content of about 10%.
And Examples of the silicone rubber include methylvinylsiloxane, a filler, and hydrogensiloxane.
Liquid A having a viscosity of 50 Pa · s at 5 ° C. and a liquid B having a viscosity of 50 Pa · s at 25 ° C. and a liquid A having a viscosity of 45 Pa · s at 45 ° C., a methylvinylsiloxane, a filler, and a platinum-based catalyst were mixed well. Used within hours.

In this embodiment, the apparatus shown in FIG. 1 is used. Adjust the tensioner 2 and set the line tension to 100.
The braided sleeve 1 was fed from the feeder stand 3 at a linear velocity of 240 m / h so as to obtain a gram. The primer was applied by dipping in the above-mentioned diluent for 2 seconds in the primer coating tank 4, the primer drying furnace 5 was set at 130 ° C., and the drying time was 10 seconds. Silicone rubber coating mechanism
6 was used as shown in FIG. The silicone rubber 7 was supplied from the supply device 8 into the silicone rubber tank 11, and the liquid level was kept constant by a level sensor and a liquid pump. The diameter of the nozzle 9 is selected to be substantially equal to the outer diameter of the braided sleeve 1, the die 10 is selected to have an opening 1 mm larger than the outer diameter of the braided sleeve 1, and the thickness of the silicone rubber is about 0.5 mm. It was made to become. The heat curing of the silicone rubber was performed by heating at a lower temperature of 200 ° C. and an upper temperature of 230 ° C. of the curing furnace 12 for 1 minute. The insulating tube 21 obtained in this way is
Rolled up.

Here, in order to examine the characteristics of the insulating tube manufactured as described above, a breakdown voltage, an inner diameter, a pinhole resistance test (based on the Electrical Appliance and Material Control Law), a low-temperature winding test (a self-diameter at 0 ° C.) The breakdown voltage after winding)
Equation 5 was used. The productivity was evaluated by examining the heat curing time of the silicone rubber and the number of steps (or the number of varnish applications) until the braided sleeve was manufactured into an insulating tube. The results are shown in Table 1 as Example 1.

[0017]

[Table 1]

Further, in Example 2, a primer using vinyltriethoxysilane, which is commonly used, was used as a primer. In Example 3, primer coating drying and silicone rubber coating were performed in separate steps, and two days were applied between the two steps. Those left to stand and handled with bare hands were evaluated in the same manner as described above, and the results are shown in Table 1. As Comparative Example 1, the viscosity of the silicone rubber at 25 ° C. was 4 Pa · s.
As Comparative Example 2, 25% of silicone rubber was used.
Those whose viscosity at 150 ° C. was increased to 150 Pa · s were evaluated in the same manner as described above, and the results are also shown in Table 1. Examples 2 and 3
In Comparative Examples 1 and 2, the conditions were the same as in Example 1 except for the conditions shown here. In addition, as a reference example, an insulating tube using an alkyd varnish (commercial product: manufactured by using a braided sleeve equivalent to that of the example and dipping and drying the varnish four times) was evaluated in the same manner as described above, and the results were evaluated. Also shown in Table 1. A method for manufacturing the insulating tube described in this reference example will be described in detail with reference to FIG. FIG. 3 is a schematic view showing an example of an apparatus for implementing a conventional (reference example) manufacturing method. Using the apparatus shown in FIG. 3, the same braided sleeve 31 as that used in Example 1 was supplied at a linear velocity of 45 m / h and the viscosity at 25 ° C. was adjusted to 0.1 Pa · S. And then dried and hardened in a drying furnace 33 for 10 minutes. This was repeated four times as shown in FIG. 3 to produce an insulating tube.

According to the present embodiment, the insulating tube manufactured by applying a silicone rubber having a viscosity of 50 Pa · s at 25 ° C. to a braided sleeve formed of polyethylene terephthalate fiber and shaping the same with a die and a nozzle is used. It can be seen that the insulating tube has excellent voltage characteristics and the like and does not lose excellent flexibility even at a low temperature. Further, it can be seen that the insulating tube of this example can be manufactured with high productivity. Further, immediately before contacting the silicone rubber, a primer containing at least titanate diluted with a solvent that easily evaporates to the braided sleeve is applied and dried, whereby the braided sleeve and the silicone rubber are firmly adhered to each other. You can see that.

[0020]

According to the present invention, excellent in withstand voltage characteristics and the like,
Flexible, easy-to-handle insulation tubes at low temperatures
Since the process can be performed in a short time in one process from the braided sleeve, it can be manufactured at the same price as a conventional alkyd varnish-coated insulating tube. For this reason, it is extremely useful in industry, for example, it can contribute to the improvement of the quality of electric products and the improvement of productivity.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus for performing a manufacturing method of the present invention.

FIG. 2 is a detailed view showing an example of a silicone rubber application mechanism in FIG.

FIG. 3 is a schematic view showing an example of an apparatus for performing a conventional (reference example) manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Braided sleeve 2 Tensioner 3 Feeder 4 Primer coating tank 5 Primer drying furnace 6 Silicone rubber coating mechanism 7 Silicone rubber 8 Feeder 9 Nozzle 10 Dies 11 Silicone rubber tank 12 Curing furnace 13 Winding roll 21 Insulating tube 31 Braided sleeve 32 Alkyd resin solution 33 Drying oven

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 70/06 B05D 1/18

Claims (2)

(57) [Claims] 1. A method of manufacturing an insulating tube comprising a braided sleeve formed of fiber and silicone rubber, wherein a viscosity of 5 Pa · s at 25 ° C. between a die having a liquid passing means and a sleeve introduction nozzle is passed through the braided sleeve. s more than 100
A method for producing an insulating tube, characterized in that a silicone rubber having a pressure of less than Pa · s is brought into contact with a silicone rubber and shaped at an upper opening of the die. 2. The method for producing an insulating tube according to claim 1, wherein the viscosity at 25 ° C. is 5 Pa · s or more and 100 P or more.
A method for producing an insulating tube, characterized in that a primer containing at least titanate diluted with a solvent that easily evaporates is applied to a braided sleeve and dried immediately before contacting a silicone rubber having a value less than a · s.