JPH0613189B2 - Thermosetting resin protection tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermosetting resin protective tube.

Currently, metal pipes and thermoplastic resin pipes are used as electric wiring for houses, buildings, factories, etc., electrical wiring for computers, equipment related to office automation, and protective tubes for fluid transfer piping in chemical factories, etc. .

These protective tubes are effective for gathering wires and pipes and at the same time preventing physical forces such as external tension and impact, and chemical erosion of corrosive atmosphere, water, chemicals, etc. The problem of flame resistance remains.

Although the metal tube itself has excellent heat resistance and flame resistance,
It has poor heat insulation and easily transfers high heat in case of fire, which may cause damage to internal wiring and piping or cause fire to spread to the surrounding area. Further, it is well known that the thermoplastic resin tube is inferior in heat resistance and flame resistance.

Therefore, it is conceivable to use a thermosetting resin tube that is rich in heat resistance, flame resistance, corrosion resistance, heat insulation, etc. for this purpose, but the conventional molding method becomes expensive and there is a problem in physical properties. Therefore, it has not been put to practical use for this purpose.

That is, a long tube of a thermosetting resin is generally formed by a plunger extrusion molding method, but in this molding method, since the extrusion pressure in the mold part is high and the extrusion is intermittent, It is difficult to obtain a uniform molded product and the productivity is low.

For this reason, a molding method using a die and a screw-type extruder has been developed. However, in this method, the resin is likely to stay, the curing reaction proceeds locally, and a slight pressure or temperature is applied. Change causes a problem such as a rapid curing reaction, which makes it difficult to continuously perform stable molding.

In addition, in both the plunger extrusion method and the extrusion method using a die and a screw extruder, the conventional molding method can obtain only low strength in the circumferential direction of the pipe, and as a result, it is weak against internal and external pressures. However, for example, a slight impact is likely to cause a crack in the axial direction of the pipe, which is a practical problem. It is considered that this is because in the conventional extrusion method, the resin itself and the fibrous filler are oriented in the extrusion direction, that is, the axial direction of the tube.

That is, in the conventional extrusion molding method, shaping and hardening are performed while the molten resin moves along the flow path in the mold, but the moving direction of the resin during that time is the extrusion direction, that is, the direction of the pipe. It is considered that the resin or the fibrous filler is oriented in that direction because it is only in the axial direction.

The present inventors have solved these drawbacks, have various heat resistance, flame resistance, corrosion resistance, as a result of various studies to provide a lightweight and inexpensive protective tube, as a result, a cylinder having a constant inner diameter Using an extruder in which a screw whose tip is a smooth part with no flight is arranged, a thermosetting resin is extruded between the smooth part of the screw and the inner wall of the cylinder to form a self-shape. The thermosetting resin tube obtained by continuously extruding from the cylinder tip after curing and shaping to the extent that it can be retained has the resin and / or fibrous filler oriented in an irregular direction, and The inventors have found that the productivity is good and arrived at the present invention.

That is, the present invention supplies a thermosetting resin to an extruder equipped with a cylinder having a constant inner diameter, and a screw having a smooth portion at the tip portion arranged in the cylinder,
A thermosetting resin protection that is continuously extruded from the tip of the cylinder after the thermosetting resin has undergone a curing reaction in the gap between the smooth part of the screw and the cylinder at that site to shape it to the extent that it can maintain its own shape. A thermosetting resin protective tube, characterized in that the resin and / or the fibrous filler are oriented in irregular directions. Since these thermosetting resin pipes usually have a ratio of the compressive strength in the direction perpendicular to the pipe axis to the compressive strength in the pipe axis direction of 0.4 to 1.5, they are excellent as thermosetting resin protective pipes. Have.

The thermosetting resin-made protective tube of the present invention described above has a uniform structure as described in, for example, the specification and drawings (Japanese Patent Application Laid-Open No. 59-178235) of the patent application relating to Japanese Patent Application No. 58-51526. Using an extruder equipped with a cylinder having an inner diameter of, and a screw having a smooth portion at the tip portion disposed in the cylinder, thermosetting resin is used in the gap between the smooth portion of the screw and the cylinder at that portion. A thermosetting resin tube, which has been difficult to extrude in the past, can be produced by a curing reaction after shaping it to the extent that it can maintain its own shape, and then continuously extruding it from the tip of the cylinder. It can be manufactured well and cheaply.

That is, in a more preferred embodiment, the thermosetting resin material charged into the extruder is heated and melted while passing through the screw supply section and the compression section, and passes through the measuring section and is spiral and smooth from the flight tip of the measuring section. Then, the frictional resistance with the inner wall of the cylinder narrows the gap portion generated by the screw flight, and finally the pressure welding is performed. Next, the resin is cured and shaped while moving through the smooth portion and extruded from the tip of the cylinder into a continuous tube.
During this time, the resin moves while receiving shearing in a direction generally along the screw groove from the supply section to the metering section, so the resin itself and the fibrous filler move in a direction that is particularly fixed with respect to the extrusion direction of the pipe. Is oriented in an irregular direction without being oriented and moves to a smooth part, and then curing proceeds, so that the resin itself and the fibrous filler are oriented in a well-balanced manner in the axial direction and the circumferential direction of the pipe. It is considered that the compression strength balance is improved in the axial direction and in the direction perpendicular to the tube axis.

The orientation of the resin or fibrous filler of the tube of the present invention can be observed by, for example, an electron microscope.

FIG. 1 is an electron micrograph showing the shape of fibers in a cross section in the extrusion direction of a phenol resin tube extruded by a conventional extrusion molding method (plunger type), and FIG. 2 is a cross section in the direction perpendicular to the extrusion direction. 3 and 4 are electron micrographs showing the shape of the fiber in each cross section of the phenol resin, which is one of the thermosetting resin protective tubes of the present invention. .

In FIGS. 1 and 2, it is clear that the glass fibers are oriented in the tube axis direction, while in FIGS. 3 and 4 the fibers are oriented in a particular direction. It is clear that they are oriented according to the husband's rule.

Table 1 below shows the compressive strength (A) in the direction perpendicular to the tube axis.
And the compressive strength (B) in the axial direction of the pipe and the ratio of A / B and the result of the water pressure test are shown. As can be seen from this table, the pipe by the conventional method has a small A / B ratio of 0.37 and has vertical cracks. In contrast to the tendency to occur, the tube of the present invention has an A / B ratio of 0.4 to 1.
It can be seen that it is strong against internal pressure without causing a large vertical crack.

In the present invention, the compressive strength in the tube axis direction is JIS-K.
A test (compressive strength test) according to paragraphs 5, 19 and 5 of -6911 was conducted to show the strength when the pipe broke (including cracks). The compressive strength in the direction perpendicular to the pipe axis is JIS. It shows the strength when a pipe is broken by conducting a test (flattening test) according to paragraphs 5 and 6 of K-6741.

In the thermosetting resin protective tube of the present invention, the ratio of the compressive strength in the direction perpendicular to the tube axis and the compressive strength in the tube axis direction according to the above method is generally 0.4 to 1.5, preferably 0.5
Is in the range of to 1.5. When this ratio is 0.4 or less, it is apt to cause an impact or longitudinal crack when it is contacted with a high internal / external pressure, and the crack extends over a long distance in the axial direction of the pipe. If this ratio is 1.5 or more, the strength becomes weak in the direction perpendicular to the tube axis and the tube is easily broken.

Examples of the thermosetting resin used in the present invention include a phenol resin, a melamine resin, a xylene resin, a urea resin, an unsaturated polyester resin, an epoxy resin, a silicone resin, an allyl resin, and an aniline resin. Particularly, a phenol resin, Melamine resin, xylene resin and the like are preferable.

The thermosetting resin used in the present invention includes a filler, a release agent, a thickener, a colorant, a dispersant, a flame retardant, and a foaming agent, which are generally used in the molding of the thermosetting resin, if necessary. Alternatively, a polymerization initiator, a curing accelerator, a polymerization inhibitor, etc. can be added. Further, other kinds of polymers or organic or inorganic fibrous substances such as glass fibers may be added.

The protective tube of the present invention made of these thermosetting resins has excellent heat resistance and is suitable for use in oils such as heavy oil, gasoline, kerosene, alcohols, ketones, esters, organic solvents such as aromatic hydrocarbons, acids, alkalis, etc. Not only is it resistant, but by using a phenol resin, melamine resin, xylene resin, etc. as a molding material, it does not spread fire even if exposed to fire, does not cause dropping, and maintains its original shape. It has flame resistance characteristics such as no generation of toxic gas.

The thermosetting resin protective tube of the present invention not only has heat resistance, flame resistance, corrosion resistance, and chemical resistance, but the resin or fibrous filler is well balanced in the tube extruding direction and the circumferential direction. Since it is oriented, it has a good balance of strength in the extrusion direction of the tube and in the direction perpendicular thereto, and is suitable as a protective tube for wiring, piping and the like.

The use of the thermosetting resin protective tube of the present invention will be specifically described. Protective tubes for indoor and outdoor general electrical wiring such as houses and buildings, factories, electrical wiring for computers and office automation related equipment, optical It can be used as a protective tube for fiber.

By using the protective tube of the present invention for these applications, not only protect electric wires and optical fibers from high temperature, water, moisture, shock, etc., but also in the event of a fire, due to its flame resistance, Prevents damage from fire and has a very low thermal conductivity compared to metal pipes, so it takes a considerable amount of time to burn out electric wires etc. inside the pipe, so appropriate measures can be taken during that time. .

Further, since the protective pipe of the present invention has excellent corrosion resistance and chemical resistance, it can be used as a protective pipe for a pipe for transferring a gas or liquid substance in a chemical plant or a general factory. Further, it can be used as a protection pipe for a penetrating portion of a pipe penetrating a wall of a building such as a house or a building. That is, in the event of a fire, if the metal pipe penetrates the wall, the metal has a good heat transfer, and the metal pipe becomes extremely hot, and the heat is transferred to the opposite side of the wall exposed to the fire, which acts as a heat source. If the thermoplastic resin pipe penetrates the wall, the pipe itself may burn, which may cause the fire to spread. When used in the penetration part, even if a fire is encountered, the pipe itself does not spread, and since it is difficult to transfer heat, the spread of fire can be prevented.

The present invention will be further described below with reference to production examples.

Production Example 1 Using an extruder having a caliber of 30 mm and L / D = 22, a compression ratio having a smooth portion having a diameter of 25 mm and a length of 120 mm (4D) at a tip portion following a measuring portion having a diameter of 25 mm at the bottom of the screw was obtained. Using the No. 3 screen, a phenol resin as a molding material (manufactured by Nippon Oil Seal Co., Ltd., trade name Rogers RX-668)
4) was used to extrude the pipe.

The temperature of each part of the cylinder is set to C ₁ (0 to 2D) = water cooling C ₂ (3D to 10D) = 80 ° C C ₃ (11D to 18D) = 100 ° C C ₄ (19D to 22D) = 120 ° C, and a screw rotation Extrusion molding was carried out under the condition of several 35 rpm to obtain a pipe having an outer diameter of 30 mm and a wall thickness of 2.5 mm.

Production Example 2 Using the same extruder as in Production Example 1, a phenol resin as a molding material (Matsushita Electric Works, Ltd., trade name CN-4610)
Was used to extrude the pipe. The temperature of each part of the cylinder is set to C ₁ = water cooling, C ₂ = 80 ° C., C ₃ = 100 ° C., C ₄ = 120 ° C., extrusion molding is performed under the condition of screw rotation speed of 35 rpm, and an outer diameter of 30 mm, A pipe having a wall thickness of 2.5 mm was obtained.

Production Example 3 Using the same extruder as in Production Example 1, a phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name PM-) was used as a molding material.
795J) was used to extrude the pipe. The temperature of each part of the cylinder is C ₁ = water cooling, C ₂ = 80 ° C, C ₃ = 100 ° C, C ₄ = 120 ° C.
And extrusion molding was carried out under the conditions of a screw rotation speed of 35 rpm to obtain a pipe having an outer diameter of 30 mm and a wall thickness of 2.5 mm.

Production Example 4 Using the same extruder as in Production Example 1, a melamine-phenol resin (manufactured by Matsushita Electric Works, Ltd., trade name M) was used as a molding material.
The pipe was extruded using EA). The temperature of each part of the cylinder is C ₁ = water cooling, C ₂ = 85 ° C, C ₃ = 120 ° C, C ₄ = 130
The temperature was set to ℃ and extrusion molding was carried out under the condition of screw rotation speed of 35 rpm to obtain a pipe having an outer diameter of 30 mm and a wall thickness of 2.5 mm.

The performance of the pipes obtained in each production example is shown in Tables 1 and 2.
It was as shown in the table. From these results, the thermosetting resin pipe of the present invention has a good balance of strength in the direction of the pipe axis and in the direction perpendicular to the pipe axis, is not only strong against internal pressure, but also has heat resistance, flame resistance, and chemical resistance. Also proves to be excellent.

[Brief description of drawings]

FIG. 1 and FIG. 2 are electron micrographs showing the shapes of the fibers in the extrusion direction of the phenol resin tube extruded by the conventional extrusion molding method (plunger method) and each cross section in the direction perpendicular to the extrusion direction, FIGS. 3 and 4 are electron micrographs showing the shape of the fibers in the cross section of the phenol resin tube which is one of the thermosetting resin protective tubes of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page Judgment panel Judge General Yasuo Hori Judge Yumiko Niki Judge Akihiro Wataya (56) References Japanese Patent Publication Sho 53-15106 (JP, B2)

Claims (2)

[Claims] 1. A thermosetting resin is supplied to an extruder equipped with a cylinder having a constant inner diameter and a screw having a smooth portion at the tip end thereof, and the thermosetting resin is supplied to the extruder. A thermosetting resin protective tube continuously extruded from the tip of the cylinder after being shaped to such an extent that it can undergo a curing reaction in the gap between the smooth portion and the cylinder at that portion to maintain the self-shape, and the resin and or A thermosetting resin protective tube in which the fibrous filler is oriented in irregular directions. 2. The thermosetting resin protective tube according to claim 1, wherein the ratio of the compressive strength in the direction perpendicular to the tube axis and the compressive strength in the tube axis direction is 0.4 to 1.5. .