JP-7857344-B2 - Tear-off tube made of fluororesin

Inventors

• 菊池 真士
• 宇田 公晴
• 尾関 三樹

Assignees

• グンゼ株式会社

Dates

Publication Date

20260512

Application Date

20240612

Priority Date

20150911

Claims (8)

1. A fluororesin tube having tearability in the longitudinal direction, It is made of a single type of thermoplastic fluororesin, which is different from polytetrafluoroethylene. The thermoplastic fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer (FEP), a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), a tetrafluoroethylene-ethylene copolymer (ETFE), or an ethylene-chlorotrifluoroethylene copolymer (ECTFE). A transparent fluoropolymer tube with weld lines running lengthwise.
2. A fluororesin tube according to claim 1, having heat-shrinkability.
3. A fluororesin tube according to claim 1 or 2, wherein the thermal shrinkage rate of the inner diameter when heated in a gas phase at 200°C for 5 minutes is 20% or more.
4. The fluororesin tube according to any one of claims 1 to 3, wherein the thermoplastic fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer.
5. The fluororesin tube according to any one of claims 1 to 3, wherein the thermoplastic fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
6. A fluororesin tube according to any one of claims 1 to 5, wherein the inner diameter can be expanded by applying pressure from the inside while heated.
7. A method for manufacturing a fluororesin tube that has tear properties, It includes a process for melt-extrude molding a single type of thermoplastic fluororesin, which is different from polytetrafluoroethylene. A method for manufacturing a transparent fluororesin tube according to any one of claims 1 to 6, wherein during the melt extrusion molding, the flow path of the molten thermoplastic fluororesin is temporarily branched to form a weld line in the longitudinal direction of the fluororesin tube.
8. The method for manufacturing a fluororesin tube according to claim 7, further comprising the step of expanding the inner diameter by applying pressure from the inside while the fluororesin tube on which the weld line is formed is heated.

Description

This invention relates to a fluororesin tube that is tear-resistant and useful as a temporary covering tube for products, and to a method for manufacturing the same. Conventionally, temporary covering tubes have been widely used for various products such as electric wires, lead wires, catheters, and guide wires. These tubes are temporarily covering the products and are removed after achieving their intended purpose. Such temporary covering tubes are generally made of synthetic resin, synthetic rubber, or similar materials. While synthetic resins and rubbers offer excellent protective properties for products, they require significant tearing force to remove. This makes them difficult to tear by hand, resulting in lengthy removal processes and the risk of damaging the product due to excessive force applied during tearing. Furthermore, methods involving damaging the tube with a cutter before tearing were employed, but these tools sometimes damaged the product inside the covering tube. As a technology to solve such problems, for example, Patent Document 1 discloses a temporary covering tube that has a uniform thickness and a lateral tensile strength of 80% or less of the longitudinal tensile strength by using a special silicone rubber. However, Patent Document 1 states that although the lateral tensile strength becomes 80% or less of the longitudinal tensile strength by using a special silicone rubber, the reason for this is unknown, and therefore the technology in Patent Document 1 is only applicable when a special silicone rubber is used. On the other hand, temporary covering tubes made of fluororesin are known to have excellent heat resistance, chemical resistance, water and oil repellency, and high mechanical strength. As a technique to improve the tear resistance of fluororesin tubes, for example, Patent Document 2 discloses a method of forming a tube by melt-extruding multiple different types of thermoplastic fluororesins. Furthermore, for example, Patent Document 3 discloses a method using a low molecular weight fluororesin relative to polytetrafluoroethylene. Japanese Patent Application Publication No. 5-208448Japanese Patent Publication No. 2008-20037Japanese Utility Model Publication No. 6-74148 This is a schematic cross-sectional view of the fluororesin tube of the present invention in the inner and outer diameter directions.This is a schematic cross-sectional view of a mold used in the melt extrusion molding method for manufacturing a fluororesin tube of the present invention (a cross-section perpendicular to the melt extrusion direction, showing the portion where the legs are located).This is an image of the inner surface of the fluororesin tube obtained in Example 1, observed with a laser microscope.This is an image of the inner surface of the fluororesin tube obtained in Example 2, observed with a laser microscope.This is an image of the inner surface of the fluororesin tube obtained in Comparative Example 1-1, observed with a laser microscope.This is an image of the inner surface of the fluororesin tube obtained in Comparative Example 2-1, observed with a laser microscope.This is a photograph of the fluororesin tube (before expansion) obtained in Example 1, with a white nylon wire inserted inside.This is a photograph of the fluororesin tube (before expansion) obtained in Example 2, with a white nylon wire inserted inside.This is a photograph of a fluororesin tube (before expansion) obtained in Comparative Example 1-1 with a white nylon wire inserted inside.This is a photograph of a fluororesin tube (before expansion) obtained in Comparative Example 2-1, with a white nylon wire inserted inside. The fluororesin tube of the present invention is characterized by having a smooth inner surface, tearability in the longitudinal direction, and being formed from a single type of thermoplastic fluororesin different from polytetrafluoroethylene. The fluororesin tube of the present invention will be described in detail below. The fluororesin tube of the present invention is formed from a single type of thermoplastic fluororesin different from polytetrafluoroethylene. The thermoplastic fluororesin is not particularly limited as long as it is different from polytetrafluoroethylene, but it is preferably a thermoplastic resin that can be molded into a tube shape by melt extrusion molding at a temperature of approximately 260 to 450°C, preferably 280 to 420°C. Specific examples of thermoplastic fluororesins include, preferably, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene copolymer (ECTFE). Among these, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) are particularly preferred from the viewpoint of providing excellent tear resistance and inner su