JPH03212432A - Non-halogen flame-retardant tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the constituent materials of tubes, particularly heat-shrinkable tubes, used for insulation coating of the end portions of electric wires (cables), protection of electronic components, etc. Regarding improvements.

In particular, the present invention uses an amorphous aromatic thermoplastic resin, especially an engineering plastic, which has excellent flame retardancy even without containing halogenated flame retardants, etc., as a constituent material of a tube, especially a heat-shrinkable tube. It's about things.

(Prior art) Heat-shrinkable tubes used for insulating the ends of electric wires (cables) or protecting electronic components have applications that require a high degree of flame retardancy, and are compliant with UL, C3A, and MI standards.
The flame retardancy test is specified by L.

Conventionally, in order to satisfy these flame retardant standards, a flame retardant containing halogen (chlorine, bromine, etc.) in the molecule has been added to Heas resin (for example, Japanese Patent Application Laid-Open No. 1-259050). (Japanese Patent Application Laid-open No. 1-256570, etc.).

In addition, tubes that shrink when heated are generally used that have a relatively high crystalline region in order to maintain the strain during expansion.

For this reason, most flame-retardant heat-shrinkable tubes are opaque.

(Question 8 to be solved by the invention) However, if a flame retardant containing halogen is added to the resin, hydrogen halide will be generated when this tube burns due to a fire, which will hinder evacuation and firefighting efforts. Something happened.

Furthermore, since many conventional heat-shrinkable tubes have an olefin resin base, it is necessary to add various anti-aging agents for long-term use at high temperatures.

Therefore, although it depends on the amount of crystalline phase, such olefin resins are generally not transparent because they have a crystalline phase, and they also have poor transparency because it is necessary to add various additives, and the inside of the tube may be damaged. This was inconvenient when it was necessary to check on the situation.

(Means for Solving the Problems) As a result of various studies to solve the above problems, the present inventors have decided to use a specific thermoplastic resin with excellent flame retardancy and heat resistance, especially engineering plastic resin, as the constituent material of the tube. The present inventors have discovered that by doing so, it is possible to create a transparent tube that has excellent flame retardancy and heat resistance even without additives such as flame retardants, and has arrived at the present invention.

That is, the present invention provides: A molecule having a limiting oxygen index of 30 or more, amorphous physical properties, a glass transition point (Tg) in the range of 120 to 220°C, and a continuous use temperature of 130°C or more. This is a non-halogen flame retardant tube that has an aromatic ring in its skeleton and uses a halogen-free thermoplastic resin as the tube material.

In particular, the non-halogen flame-retardant tube of the present invention is useful as a heat-shrinkable tube that causes thermal contraction in the radial direction of the tube by heating the tube material.

Further, it will be explained in detail.

The tube material used in the present invention must have (1) a critical oxygen index of 30 or more, preferably 30 to 55;

Therefore, this tube material depends on the tube wall thickness.
It is highly flame retardant in normal air.

The critical oxygen index refers to the minimum oxygen concentration at which the resin continues to burn, and refers to a value measured by the test method specified in ASTM D 2863-87.

■ In addition, since the tubing material of the present invention has a continuous use temperature of 130°C or higher, it is not necessary to add an anti-aging agent as is usually done when exposed to high temperatures for a long time. There is no.

The continuous use temperature here refers to the temperature at which the elongation of the resin decreases to 50% of the initial value when exposed to air at that temperature for 10,000 hours, and even if used continuously at this specific set temperature, discoloration will occur. Or, the strength etc. will not decrease.

■Furthermore, the tube material of the present invention has a relatively high glass transition temperature (Tg) of 120 to 220°C.
(a) A relatively high crystallization region required for heat-shrinkable tubes such as conventional olefin resins is no longer required, and the tube can be expanded around this Tg and then rapidly cooled. This has the advantage of providing heat-shrinkable tubing.

(0) In addition, unlike conventional heat-shrinkable tubes made of olefin resin, there is no need for the process of maintaining strain by expanding and cooling to utilize crystalline phase formation within the olefin resin after crosslinking with ionizing radiation. The invention utilizes the phenomenon that tube materials change significantly at temperatures near the glass transition point, and has the advantage that a heat-shrinkable tube can be obtained simply by heating.

■ As mentioned in ■ above, the tube material of the present invention is
It eliminates the need for a relatively high crystallization region like conventional olefin resins and allows an amorphous structure, making it possible to produce transparent heat-shrinkable tubes, which was impossible with conventional heat-shrinkable tubes. It has become possible.

(2) Since the tube material of the present invention has an aromatic ring in its molecular skeleton, it has better heat resistance than conventional olefin resin heat-shrinkable tubes.

(2) Since the tube material of the present invention has a non-halogen structure, there is no risk of generating toxic hydrogen halides even if it is burned in a fire or the like.

As described above, since the tube material of the present invention has the above-mentioned components 1 to 3, it has good transparency, flame retardancy, and heat resistance, and a heat-shrinkable tube can be obtained by a simple heating process. .

The tube material of the present invention has a limiting oxygen index of 30 or more, amorphous physical properties, and a glass transition point (Tg) of 120.
Any thermoplastic resin can be used as long as it has an aromatic ring in its molecular skeleton and does not contain halogen, has a continuous operating temperature of 130°C or higher, and is in the range of 220°C. Tsuku is preferably used.

Specific examples include polyarylate resin, aromatic polyetherimide resin, aromatic polyether sulfone,
Examples include aromatic polysulfone.

In addition to the above-mentioned specific resin, other heat-shrinkable tube materials, such as olefin resins, may be blended into the tube material of the present invention in a small amount within a range that does not impair the object of the present invention.

The tube material of the present invention is deformed in the radial direction at a temperature near the glass transition point (Tg) of the tube material, for example, expanded or stretched by applying internal pressure. If it is heated above the glass transition point after it is placed on an object, it will shrink to its original diameter, allowing the object to be covered to be densely covered.

In this case, crosslinking using ionizing radiation or chemical crosslinking may be performed in advance before heating and expanding.

Of course, various additives such as inorganic flame retardants, antioxidants, and pigments may be added to the tube material of the present invention to the extent that its transparency is not impaired.

(Function) (1) The tube material of the present invention has a limiting oxygen index of 30 or more, so it is extremely flame retardant in normal air.

■ The tube material of the present invention has a continuous use temperature of 130℃.
Because of the above, when exposure to high temperatures for a long time is expected, there is no need to add an anti-aging agent, which is usually done.

(2) The tube material of the present invention does not require any additives, so if the material itself has transparency, the tube can also maintain high transparency like the material itself.

(2) To impart heat shrinkability to the tube material of the present invention, it is sufficient to simply expand the obtained tube near the glass transition point of the tube material and rapidly cool it.

This operation fixes the strain caused by the expansion, and then when heated above the glass transition point, the tube can easily contract in the radial direction to alleviate the fixed strain.

In other words, after crosslinking with ionizing radiation, which was done with conventional heat-shrinkable tubes such as polyolefin resins, expansion and
In the present invention, we have developed a series of processes that utilize crystalline phase formation within polyolefin resins to maintain strain by cooling, but the present invention has developed a process in which the mobility of the polymer main chain changes significantly near the glass transition point. By using it, we are replacing it.

Thus, the tubing materials of the present invention do not require the relatively high crystallization areas of conventional heat shrink tubing.

The present invention will be specifically explained by the following examples, but these are not intended to limit the scope of the present invention.

(Example) As shown in Table 1, polyarylate resin, polyetherimide resin, polyethersulfone resin, and polysulfone resin, which have excellent flame retardancy and transparency, are used as tube materials and extruded into tubes. , perform expansion, contractility,
Flame retardancy etc. were evaluated. The resins used in the examples are as follows.

Polyarylate: U-100 manufactured by Unitika, Polyetherimide: ULTEM1000 manufactured by EPL, Polyethersulfone: VI CTRE manufactured by IC1
X-4100G.

Polysulfone: P-1700 manufactured by Amoco, Table 2 *6: Irganox 1010 manufactured by Chiha Geigy (effects of the invention) As explained above, the non-halogen flame-retardant tube using the specific flame-retardant engineering plastic material of the present invention Since it can be heat-shrinked while maintaining its transparency, and has flame retardancy and high heat resistance, it is particularly useful when used to protect electrical and electronic components exposed to high temperatures.

Claims (2)

[Claims] (1) Has a limiting oxygen index of 30 or more, has amorphous physical properties, has a glass transition point (Tg) in the range of 120 to 220°C, and has a continuous use temperature of 130°C or more. A non-halogen flame-retardant tube characterized by having an aromatic ring and using a halogen-free thermoplastic resin as the tube material. (2) The non-halogen flame-retardant tube according to claim (1), wherein the tube material undergoes thermal contraction in the tube radial direction when heated.