JP2020001239A - Sheathing material and manufacturing method thereof - Google Patents

Abstract

To provide a sheathing material having a good curling property capable of firmly covering an object with a high winding stress, and a manufacturing method thereof.SOLUTION: The manufacturing method of a sheathing material 20 having the good curling property comprises a first step (a) of manufacturing a laminated sheet 10 by providing a layer 12 made of a rubber composition on a resin film 11, a second step (b) of primarily vulcanizing the rubber composition after winding the laminated sheet 10 around a core rod 13, and a third step (c) of secondarily vulcanizing a primarily vulcanized rubber composition after removing the resin film 11 from the laminated sheet 10 wound around the core rod 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a covering material and a method for producing the same.

  As a method for preventing the target object from being deteriorated by air or water, for example, a connection portion such as an electric wire is wrapped with an electrically insulating tape, and the outer periphery thereof is covered with an insulating cover such as a rubber sheet. As the cover, a sheet having a curl is widely used in consideration of workability. As such a cover, for example, Patent Literature 1 discloses a crimpable rubber sheet for a cable joint cover made of ethylene propylene rubber. As a method for producing the cover, a primary vulcanized planar rubber sheet is used. Is wound around a core rod to form a habit. Further, Patent Literature 2 discloses an insulating cover in which a winding habit having a diameter smaller than the outer diameter of the bare wire is provided at both end edges of the sheet.

JP-A-63-66020 JP 2003-244829 A

However, if the winding stress is weak, a gap is formed between the electric wire and the cover, and there is a problem that deterioration due to wind and rain easily proceeds. Furthermore, a member for further tightening the cover to fill the gap between the electric wire and the cover and an operation for the member are required.
In the rubber sheet and the insulating cover described in Patent Literatures 1 and 2, the winding stress was not satisfactory in that the rubber sheet and the insulating cover had good adhesion to an object such as an electric wire and were firmly covered.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a covering material having strong winding stress and having a curl that can firmly cover an object, and a method for manufacturing the same.

The present inventors have conducted intensive studies and found that, by winding an unvulcanized silicone rubber composition around a core rod and performing vulcanization, the coating has a strong winding stress, and has a winding habit that can tightly cover electric wires and the like. It has been found that a material can be obtained, which has led to the present invention.
That is, the present invention
On the resin film, a first step of providing a layer made of a rubber composition to produce a laminated sheet,
After winding the laminated sheet around a core rod, a second step of primary vulcanization of the rubber composition,
After removing the resin film from the laminated sheet wound on the core rod, a third step of secondary vulcanization of the primary vulcanized rubber composition,
It is a manufacturing method of the covering material provided with.

  The rubber composition is preferably a silicone rubber composition.

  The resin film is preferably made of polyethylene terephthalate, polypropylene, polyethylene, polyamide, or polyamide imide.

  The thickness of the resin film is preferably 25 μm or more and 150 μm or less.

  The surface of the resin film on which the layer made of the rubber composition is provided may have an uneven structure, and the surface roughness Ra of the uneven structure is preferably 0.01 or more and 2.0 or less.

  In the third step, after unwinding the laminated sheet wound around the core rod and removing the core rod, the resin film and the layer made of the rubber composition may be peeled off.

The coating material of the present invention is a coating material having a curl made of a flexible material,
The winding stress is constant in the 80% region from the end of winding to the beginning of winding.

In the coating material of the present invention, in a tensile test described below, it is preferable that an increase in stress per 10 mm in a region of 80% from the end of winding to the beginning of winding is 0.04 N or less.
(Tensile test)
Coating material: width 50mm, thickness 1mm, roll length 150mm
The stress at the time of unwinding while pulling at a pulling speed of 500 mm / min in the vertical direction from the end of the outermost layer of the coating material is measured every 10 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the winding stress is strong and the coating material which has the curl which can coat | cover a target object firmly can be obtained.

FIG. 1 is a diagram showing a method for producing a coating material of the present invention. FIG. 2 is a schematic sectional view showing an example of the resin film in the present invention. FIG. 3 is a schematic sectional view showing an example of the laminated sheet in the present invention. FIG. 4 is a diagram showing a method for measuring the winding stress of the coating material of the present invention. FIG. 5 is a graph showing the winding stress of the example and the comparative example.

  Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are presented for the purpose of illustration, and the present invention is not limited to the embodiments described below.

[Production method of coating material]
As shown in FIG. 1A, the method of manufacturing the coating material 12 according to the present invention includes a first step of providing a layer 12 made of a rubber composition on a resin film 11 to produce a laminated sheet 10; As shown in FIG. 1 (b), after winding the laminated sheet 10 around the core rod 13, a second step of primary vulcanization of the rubber composition and the resin film 11 from the laminated sheet 10 wound around the core rod 13 are performed. After the removal, as shown in FIG. 1 (c), a third step of secondary vulcanizing the primary vulcanized rubber composition is provided. Through the first to third steps, a coating material 20 having a curl as shown in FIG. 1D is obtained.
Hereinafter, each manufacturing process will be described.

(First step)
In the first step, as shown in FIG. 1A, a layer 12 made of a rubber composition is provided on a resin film 11 to produce a laminated sheet 10. At this point, the rubber composition is in an unvulcanized state.
As a method for providing the layer 12 made of the rubber composition on the resin film 11, a method using a two-roll or calender roll forming machine is exemplified.

-Resin film-
As the resin film, polyethylene terephthalate, polypropylene, polyethylene, polyamide, polyamideimide, or the like is preferable. From the viewpoint of processability and heat resistance, polyethylene terephthalate is more preferred.

  The thickness of the resin film 11 is preferably 25 μm or more and 150 μm or less. When it is 25 μm or more, it has sufficient resistance to heat during vulcanization and has sufficient strength for winding around the core rod 13. When the thickness is 150 μm or less, the gap between the vulcanized rubber sheets can be reduced, so that the winding can be further strengthened and the outer diameter of the coating material can be reduced.

As shown in FIG. 2, the surface of the resin film 11 on which the layer 12 made of the rubber composition is provided may have an uneven structure 11a. In the case of having the uneven structure 11a, the uneven structure is formed on the layer 12 made of the rubber composition on the side of the resin film 11 which is in contact with the uneven structure 11a. Has a stopping function.
The surface roughness Ra of the uneven structure 11a is preferably 0.01 or more and 2.0 or less, and more preferably 0.3 or more and 0.8 or less. When it is 0.3 or more, it is possible to have a good anti-slip function, and when it is 1.0 or less, it is possible to more firmly coat the target with good adhesion.
The surface roughness Ra of the surface of the resin film 11 opposite to the surface on which the layer 12 made of the rubber composition is provided is preferably a mirror surface, and specifically, is preferably 0.03 or less. .

-Rubber composition-
As the rubber composition, a silicone rubber composition, a fluorine rubber composition, a urethane rubber composition, an ethylene / propylene rubber, or a chloroprene rubber composition is preferable. In particular, a silicone rubber composition is preferred from the viewpoints of heat resistance, weather resistance, and electrical insulation.

As the silicone rubber composition, a millable silicone rubber composition having a certain degree of viscosity is preferable.
The millable silicone rubber composition preferably contains the following components.
The millable silicone rubber composition may contain, for example, (A) an organopolysiloxane represented by the following average composition formula (1), and (B) a filler.
R ¹ _n SiO _{(4-n) / 2} (1)
In the formula (1), n represents a positive number from 1.95 to 2.05. R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 12 or less, more preferably 1 or more and 8 or less.

Examples of R ¹ include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and a dodecyl group, a cycloalkyl group such as a cyclohexyl group, a vinyl group, an allyl group, a butenyl group, and a hexenyl group. And aryl groups such as alkenyl group, phenyl group and tolyl group, and aralkyl groups such as β-phenylpropyl group. R ¹ may be a group in which part or all of the hydrogen atoms of these hydrocarbon groups are substituted with a substituent. The substituent may be, for example, a halogen atom, a cyano group, or the like. Examples of the hydrocarbon group having a substituent include a chloromethyl group, a trifluoropropyl group, and a cyanoethyl group.

  (A) The organopolysiloxane has a molecular chain terminal such as a trialkylsilyl group such as a trimethylsilyl group, a dialkylaralkylsilyl group such as a dimethylvinylsilyl group, a dialkylhydroxysilyl group such as a dimethylhydroxysilyl group, and a trivinylsilyl group. It is preferably blocked with a triaralkylsilyl group or the like.

(A) The organopolysiloxane preferably has two or more alkenyl groups in the molecule. (A) The organopolysiloxane preferably has 0.001 mol% to 5 mol% (more preferably 0.01 mol% to 0.5 mol%) of the alkenyl group in R ¹ . As the alkenyl group contained in the organopolysiloxane (A), a vinyl group is particularly preferred.

  (A) The organopolysiloxane is obtained by, for example, cohydrolytic condensation of one or more organohalosilanes, or ring-opening polymerization of a cyclic polysiloxane such as a trimer or tetramer of a siloxane. Can be obtained by: (A) The organopolysiloxane may be basically a linear diorganopolysiloxane, and may be partially branched. Further, the organopolysiloxane (A) may be a mixture of two or more kinds having different molecular structures.

  (A) The organopolysiloxane preferably has a kinematic viscosity at 25 ° C. of at least 100 cSt, more preferably at least 100,000 cSt and at most 100,000,000 cSt. Further, the polymerization degree of the organopolysiloxane (A) is, for example, preferably 100 cSt or more, and more preferably 3000 cSt or more and 10,000 cSt or less.

  Examples of the filler (B) include silica-based fillers. Examples of the silica-based filler include fumed silica and precipitated silica.

As the silica-based filler, a surface-treated silica-based filler surface-treated with a silane coupling agent represented by R ² Si (OR ³ ) ₃ can be suitably used. Here, R ² may be a group having a vinyl group or an amino group, for example, a glycidyl group, a vinyl group, an aminopropyl group, a methacryloxy group, an N-phenylaminopropyl group, a mercapto group, or the like. R ³ may be an alkyl group, for example, a methyl group, an ethyl group, or the like. As the silane coupling, for example, brand names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. can be easily obtained. The surface-treated silica-based filler can be obtained by treating the surface of the silica-based filler with a silane coupling agent according to a standard method. Commercially available products may be used as the surface-treated silica-based filler. M. A brand name “Zeothix 95” manufactured by HUBER Inc. is exemplified.

  The amount of the silica-based filler is preferably from 11 parts by mass to 39 parts by mass, and more preferably from 15 parts by mass to 35 parts by mass, per 100 parts by mass of the organopolysiloxane (A), from the viewpoint of improving the insulating properties. It is more preferred that: The average particle size of the silica-based filler is preferably 1 μm or more and 80 μm or less, more preferably 2 μm or more and 40 μm or less. The average particle diameter of the silica-based filler can be measured as a median diameter using a particle size distribution measuring device based on a laser light diffraction method.

  The millable silicone rubber composition may further contain additives in addition to (A) and (B). Examples of additives include auxiliaries (chain extenders, crosslinking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, Examples thereof include an emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, and a solvent.

  Specific examples of the additives include (A) silanol groups at both ends such as dimethylsiloxane oil, polyether-modified silicone oil, silanol, diphenylsilanediol and α, ω-dimethylsiloxanediol having a lower polymerization degree than organopolysiloxane. Dispersants such as low molecular siloxane and silane are exemplified. Further, specific examples of the additive include a heat resistance improver such as iron octylate, iron oxide, and cerium oxide. Further, as the additive, various carbon functional silanes, various olefin-based elastomers, and the like for improving adhesiveness, moldability, and the like may be used.

  The layer 12 made of the rubber composition on the laminated sheet 10 may have a laminated structure. For example, as shown in FIG. 3, a laminated sheet 30 in which a layer 31 made of a rubber composition and a layer 32 made of a foamed rubber composition having high heat insulation properties may be provided on the resin film 11. With such a laminated structure, the heat insulating property to the object can be improved.

(Second step)
The second step is a step of first vulcanizing the rubber composition after winding the laminated sheet 10 around the core rod 13 as shown in FIG. 1 (b).

-Core rod-
Examples of the material of the core rod 13 include iron, aluminum, stainless steel, and brass.
The cross-sectional shape of the core rod 13 is not particularly limited, and may be a circle, an ellipse, or a polygon. That is, by forming the same shape as the object to be coated, a coating material having higher adhesion can be obtained.
The primary vulcanization is not particularly limited, and is preferably performed at 130 ° C. or more and 250 ° C. or less for 20 minutes or more and 60 minutes or less.

(Third step)
In the third step, as shown in FIG. 1C, a step of removing the resin film 11 from the laminated sheet 10 wound around the core rod 13 and then secondary vulcanizing the primary vulcanized rubber composition. It is.
The secondary vulcanization is for removing impurities from the primary vulcanized rubber composition, and is preferably performed at a temperature of 180 ° C to 250 ° C for 30 minutes to 10 hours.

  The resin film 11 is preferably formed by unwinding the laminated sheet 10 wound around the core rod 13 from the core rod 13 and peeling and removing the resin film 11 and the layer 12 made of the rubber composition. Since the resin film 11 and the layer 12 made of the rubber composition are quasi-adhered after the secondary vulcanization, the layer 12 made of the rubber composition can be easily peeled off from the resin film 11.

[Coating material]
The coating material manufactured by the manufacturing method of the coating material of the present invention, a thin resin film, a laminated sheet provided with a layer made of a rubber composition, the primary vulcanization and secondary vulcanization after winding a core rod. Therefore, the winding stress is strong, and the object can be firmly coated with good adhesion.
The coating material manufactured by the manufacturing method of the coating material of the present invention has a high gripping force on the target object and can protect the target object from air and water satisfactorily, such as a metal joint or a wire joint. It is useful as a coating material for coating.

  Hereinafter, the present invention will be described in detail with reference to examples. It should be noted that the present invention is not limited to the embodiments described below.

[Example 1]
To 100 parts by mass of KE-9710-U (silicone rubber compound manufactured by Shin-Etsu Chemical Co., Ltd.), an appropriate amount of C-23N (vulcanizing agent manufactured by Shin-Etsu Chemical Co., Ltd.) is added, and after kneading with two rolls, calender roll Then, the silicone rubber composition having a thickness of 1.0 mm was subjected to a topping process on a polyethylene terephthalate resin film having a thickness of 100 μm, and cut into 50 mm × 150 mm.
Next, the cut product was wound around a SUS φ8 (mm) core rod having a length of 100 mm, and the end was fixed with a heat-resistant masking tape.
The wound product was subjected to primary vulcanization at 150 ° C. for 30 minutes in a gear oven, cooled to room temperature, and then unraveled from the core bar, and the polyethylene terephthalate resin film was removed to obtain a silicone rubber with a curl.
The obtained silicone rubber having a curl was further subjected to secondary vulcanization at 200 ° C. for 4 hours. The winding stress was measured by the following predetermined winding stress measurement method.

[Comparative Example 1]
Using the same raw materials as in Example 1, molding was performed in an extruder in a wound state, and primary vulcanization was performed in a HAV vulcanizing furnace at 300 ° C. under vulcanization conditions equivalent to 20 seconds. .
Next, it was cut to 50 mm, subjected to secondary vulcanization in the same manner as in Example 1, and the winding stress was measured.

[Winding stress measurement method]
FIG. 4 shows a method for measuring the winding stress.
As shown in FIG. 4A, first, a coating material (silicone rubber) 45 having a curl with a curl adjusted to a width of 50 mm, a thickness of 1 mm, and a roll length of 150 mm is prepared. A double-sided tape for silicone is attached to a portion 10 mm from the end of the outermost layer of the coating material 45 having a curl, and attached to a SUS metal plate (20 mm × 100 mm × 2 mm) 43. On the other hand, a SUS core rod (φ6 mm, length 100 mm) 44 is inserted into the center of the winding to produce a part for measurement. One end of the SUS core rod 44 is attached to the lower chuck 42 of the tensile tester 40, and the SUS metal plate 43 is attached to the upper chuck 41.
Next, as shown in FIG. 4B, the upper chuck 41 was vertically moved at a pulling speed of 500 mm / min while the lower chuck 42 was fixed. The stress was measured at this time, and the value was defined as the winding stress.

  Table 1 shows the measurement results of Example 1 and Table 2 shows the measurement results of Comparative Example 1. FIG. 5 shows a graph comparing the winding stress between Example 1 and Comparative Example 1.

As shown in FIG. 5, the winding stress constantly increases from the end of winding (upper chuck moving distance of 0 mm) to the beginning of winding (upper chuck moving distance of 100 mm). That is, it can be seen that there is a strong winding stress from the winding start to the winding end. In particular, at least in the region of 80% from the end of winding to the start of winding (moving distance of the upper chuck from 10 mm to 90 mm), the amount of change in stress every 10 mm is within plus 0.40, and uniform winding stress is obtained. You can see that it is wound with.
On the other hand, in Comparative Example 1 which was not manufactured by the manufacturing method of the present invention, there were a region where the winding stress increased and a region where the winding stress decreased from the end of winding to the start of winding. That is, it is understood that the winding stress is not wound with a constant force.
Furthermore, in the example, the winding stress at the start of winding (the upper chuck moving distance is 100 mm) is 3.44 N, which is much higher than the comparative example of 2.70 N.
From the above measurement results, it can be seen that the coating material having a curl produced by the production method of the present invention can firmly coat the target object, and thus has improved adhesion. In particular, by changing the shape of the core rod according to the external shape of the object, it has excellent adhesion to various objects.

DESCRIPTION OF SYMBOLS 10 Laminated sheet 11 Resin film 12 Layer composed of rubber composition 13 Core rod 15 End 20 Coating material 11a Concavo-convex structure 30 Laminated sheet 31 Layer composed of rubber composition 32 Layer composed of foamed rubber composition 40 Tensile tester 41 Upper chuck 42 Lower chuck 43 SUS metal plate 44 SUS core rod 45 Curling coating material

Claims (8)

On the resin film, a first step of providing a layer made of a rubber composition to produce a laminated sheet,
After winding the laminated sheet around a core rod, a second step of primary vulcanization of the rubber composition,
Removing the resin film from the laminated sheet wound around the core rod, and then secondary vulcanizing the primary vulcanized rubber composition.   The method for producing a coating material according to claim 1, wherein the rubber composition is a silicone rubber composition.   The method according to claim 1, wherein the resin film is made of polyethylene terephthalate, polypropylene, polyethylene, polyamide, or polyamideimide.   The method for producing a coating material according to claim 1, wherein a thickness of the resin film is 25 μm or more and 150 μm or less.   The resin film has an uneven structure on a surface on which a layer made of the rubber composition is provided, and a surface roughness Ra of the uneven structure is 0.01 to 2.0. The method for producing a coating material according to claim 1.   In the third step, after unwinding the laminated sheet wound around the core rod, removing the core rod, peeling off the resin film and the layer made of the rubber composition. A method for producing a coating material according to any one of the preceding claims. A coating material having a curl made of a flexible material,
A coating material having a constant winding stress in a region of 80% from the end of winding to the beginning of winding. The coating material according to claim 7, wherein in the tensile test described below, the amount of increase in stress per 10 mm in an area of 80% from the end of winding to the start of winding is 0.04 N or less.
(Tensile test)
Coating material: width 50mm, thickness 1mm, roll length 150mm
The stress at the time of unwinding while pulling at a pulling speed of 500 mm / min in the vertical direction from the end of the outermost layer of the coating material is measured every 10 mm.

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