JPH0753390B2 - Multi-layer pipe fitting - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multilayer pipe joint used for connecting a water supply pipe, a hot water supply pipe, and the like, and more specifically, a resin excellent in heat resistance, chemical resistance, and the like. Manufactured multilayer pipe joint.

(Prior Art) Pipe fittings for connecting the water supply pipe and the hot water supply pipe are made of metal, general-purpose resin such as vinyl chloride resin, or so-called engineering plastic such as polyetherimide or polyetheretherketone. Etc. have been proposed.

(Problems to be Solved by the Invention) The metal pipe joint has poor productivity and is disadvantageous in terms of cost. Moreover, since it has the problem of rust,
It has inferior hot water resistance, chemical resistance, and weather resistance, and is also heavy.

Pipe joints made of general-purpose resins have a relatively low softening point, and therefore have poor heat resistance and hot water resistance under stress.

Among the above engineering plastics, the pipe joint formed of polyetherimide is superior in heat resistance and mechanical properties to the pipe joint made of general-purpose resin. However, even this pipe joint has insufficient heat resistance and hot water resistance under stress.

Since the above-mentioned polyether ether ketone or polyether nitrile has a high melting point, the pipe joint formed of this resin is extremely excellent in heat resistance, hot water resistance, chemical resistance and the like. However, since polyetherketone is colored (gray green), there is a drawback that the pipe joint cannot be colored freely, and the cost is high.

The present invention was made by paying attention to such actual situation,
Light weight, excellent in productivity, strength, heat resistance, hot water resistance,
An object of the present invention is to provide a resin multi-layer pipe joint which is excellent in moldability and chemical resistance, can be colored arbitrarily, and can be provided at a relatively low cost.

(Means for Solving the Problem) The multilayer pipe joint of the present invention has a tubular inner layer in contact with fluid and a tubular outer layer provided outside the inner layer, and is made of a molding material. A pipe joint having a multilayer structure in the thickness direction, the inner layer being formed of a molding material containing polyether ether ketone or polyether nitrile as a main component, and the outer layer containing a resin other than polyether ether ketone or polyether nitrile as a main component. It is formed of a molding material of which the above-mentioned object is achieved.

The polyether ether ketone (hereinafter referred to as PEEK) used in the present invention is a special engineering plastic developed by ICI and has a melting point of 334 ° C. PEEK is lightweight and has excellent physical properties such as heat resistance, hot water resistance, and chemical resistance.

PEEK has a structure with the following repeating units.

Commercially available PEEK is VICTREX PEEK (trademark of ICI).

The polyether nitrile used in the present invention is a special engineering plastic developed by Idemitsu Kosan Co., Ltd., and its melting point is 340 ° C. Polyether nitrile is lightweight and has excellent physical properties such as heat resistance, hot water resistance, and chemical resistance. Polyether nitrile has a structure having the following repeating units.

A commercially available product of polyether nitrile is ID300 (trademark of Idemitsu Kosan Co., Ltd.).

The molding material forming the inner layer may contain PEEK or polyether nitrile as a main component and other additives. Since the outer layer is provided outside the inner layer, it is not particularly necessary to add a coloring agent. The thickness of the inner layer is preferably 1 mm or more, and particularly preferably 1.5 to 5 mm. If the thickness is less than 1 mm, blistering may occur and the heat resistance of the multilayer pipe joint may be poor. In addition, heat conduction may soften the outer layer. If the thickness is too thick, there is a cost disadvantage.

As the resin contained in the molding material forming the outer layer, for example, polyamide, polyethylene, polypropylene, polybutylene terephthalate, polyvinyl chloride, polyacetal, polycarbonate, polyether sulfone,
Polyphenylene oxide, polyphenylene sulfide,
Examples thereof include resins such as polysulfone and polyetherimide, with polyetherimide, polysulfone, polyethersulfone and polyphenylene sulfide being particularly preferable. These resins are excellent in heat-sealing property with PEEK and polyether nitrile, and also relatively excellent in heat resistance, weather resistance, pressure resistance and impact resistance, and can be colored.

In addition, each molding material includes a filler for reinforcement, a coloring agent,
Antiaging agents and the like are added as necessary.

Examples of the filler include glass fibers, carbon fibers, boron fibers, silicon carbide fibers, alumina fibers, amorphous fibers, inorganic fibers such as silicon / titanium / carbon fibers, and organic fibers such as aramid fibers. Is added within a range that does not impair

The fiber length and fiber diameter of the above-mentioned inorganic fibers and organic fibers are not particularly limited, but the fiber length is preferably 2 to 3 mm or less, and the fiber diameter is 5 to 25 μm.
A degree is preferable. The glass fiber used in the following examples has a fiber length of 0.5 mm and a fiber diameter of 13 μm.

Specifically, the adhesion between PEEK or polyether nitrile and the molding material in which the above resin is mixed with 30 to 40% by weight of glass fiber is as follows.

PEEK and polyetherimide molding material (glass fiber 30% by weight) ... 220 Kg / cm ² PEEK and polysulfone molding material (glass fiber 30% by weight)
… 350Kg / cm ² PEEK and polyether sulfone molding material (glass fiber 30
Weight%)… 150Kg / cm ² PEEK and polyphenylene sulfide molding material (glass fiber
40 wt%)… 165 Kg / cm ² Polyether nitrile and polyether imide molding material (glass fiber 30 wt%)… 200 Kg / cm ² Polyether nitrile and polysulfone molding material (glass fiber 30 wt%)… 340 Kg / cm ² poly Ether nitrile and polyether sulfone molding material (glass fiber 30% by weight): 200 Kg / cm ² Polyether nitrile and polyphenylene sulfide molding material (glass fiber 40% by weight): 150 Kg / cm ² Further adhesion between inner and outer layers To increase, for example,
The following method can be adopted.

A concavo-convex portion is provided at the contacting portion of both layers.

An intermediate layer containing the resin contained in both layers is provided at the interface of both layers.

An adhesive layer is provided at the interface between both layers.

In the above, PEEK or polyether nitrile contained in the molding material for the intermediate layer is preferably 10 to 90% by weight. If it is out of this range, the adhesiveness will decrease. The molding material for forming the intermediate layer can be obtained by a screw type kneader, a roll, a press or the like, but pellets of both resins may be dry blended and put into an injection molding machine.

In the above, epoxy type, cyanoacrylate type,
An adhesive such as a silicone adhesive can be used, and the adhesive can be applied by coating one of the inner layer and the outer layer and drying.

In this way, by improving the adhesiveness of both layers, it is possible to prevent both layers from peeling and cracking due to an external impact such as trampling, and it is possible to prevent the tube from being blocked.

In order to manufacture a multilayer pipe joint, it can be easily molded using, for example, a general multilayer injection molding machine. As the order of injecting the molding material, it is preferable to inject the molding material having the lower melting point first in order to improve the adhesion. That is, when a molding material having a high melting point is injected, the fusion property of both layers can be improved by slightly softening the surface of the solidified molded article made of the molding material having a low melting point that was previously injection molded. . Further, in the present invention, since the melting point of the resin used is high, the mold temperature is preferably 100 ° C to 180 ° C. By setting the mold temperature high in this way, the resin is slightly softened and the interfaces of both layers are easily fused. Mold temperature is 18
If the temperature exceeds 0 ° C, the molding material may soften and the shape of the molding material may not be retained.

As described above, in the present invention, by forming the inner layer in contact with the fluid with PEEK, heat resistance, hot water resistance and the like are increased, and by forming the outer layer not in contact with the fluid with the above resin, weather resistance, impact resistance, It is possible to supplement the points of economy and coloring. Particularly, by adding the pigment to the molding material of the outer layer without adding the pigment to the molding material of the inner layer, the multilayer pipe joint can be freely colored without deteriorating the physical properties of the inner layer.

Further, in the present invention, since the thermoplastic resin is used for the inner layer and the outer layer and the multilayer pipe joint is formed by injection molding,
Continuous production becomes possible and productivity is improved, and it is possible to prevent quality variations.

(Example) Hereinafter, the present invention will be specifically described based on Examples.

As shown in FIG. 1, the multilayer pipe joint includes a cylindrical inner layer 1 and
It has a cylindrical outer layer 2 bonded to the outside of the inner layer 1. A groove 4 is provided in the central portion of the outer peripheral surface of the inner layer 1 in the longitudinal direction, and the base of the outer layer 2 is fitted in the groove 4. Ring-shaped grooves 5 are formed at both ends in the longitudinal direction of the outer peripheral surface of the inner layer 1, and packings 6 are fitted in the ring grooves 5.

In order to connect a pair of pipes 7, 7 using such a multilayer pipe joint A, as shown in the figure, a slit ring 8 and a cap nut 9 are fitted to both ends of the multilayer pipe joint A, respectively. Between the outer surface of the end of the pipe joint A and the slit ring 8, the pipe 7
Insert the end of the and insert the cap nut 9 into the slit ring 8
The end portion of the pipe 7 can be clamped by the slit ring 8 so that the end portion of the pipe 7 can be sandwiched between the slit ring 8 and the outer surface of the multilayer pipe joint A.

Next, a specific numerical value will be described.

Experimental Example 1 PEEK was used to make pellets for the inner layer, and a molding material in which 30% glass fiber was mixed with polyetherimide was used to make pellets for the outer layer.

Using the above-mentioned pellets, a multilayer injection molding machine was used to mold the multilayer pipe joint shown in FIG. 1, and the resultant was annealed at 180 ° C. for 1 hour to crystallize PEEK to obtain a multilayer pipe joint. The thickness of the inner layer of the obtained multilayer pipe joint was 1 mm. The adhesion strength of both layers was measured and found to be 220 Kg / cm ² .

Next, using this multi-layered pipe joint, connect a pair of pipes as shown in Fig. 1, and pass hot water into this pipe (90 ° C x 10 kg / cm)
Also, when the outer surface was immersed in water at 35 ° C and a blister resistance test was performed, no decrease in adhesion was observed even after 5000 hours,
No clogging of the multi-layer pipe joint (blister) was observed.

Experimental Example 2 A multilayer pipe joint was obtained in the same manner as in Experimental Example 1, except that the polysulfone molding material (glass fiber 30% by weight) was used instead of the polyetherimide molding material (glass fiber 30% by weight). The annealing treatment was performed at 170 ° C. for 1 hour.

The obtained multilayer pipe joint was tested for physical properties in the same manner as in Experimental Example 1, and showed good adhesion, no breakage, and no blisters.

Experimental Example 3 Instead of the polyetherimide molding material (glass fiber 30% by weight), a polyether sulfone molding material (glass fiber)
A multilayer pipe joint was obtained in the same manner as in Experimental Example 1 except that 30% by weight) was used. The annealing treatment was performed at 170 ° C. for 1 hour.

The obtained multilayer pipe joint was tested for physical properties in the same manner as in Experimental Example 1, and showed good adhesion, no breakage, and no blisters.

Experimental Example 4 A multilayer pipe joint was obtained in the same manner as in Experimental Example 1 except that a polyphenylene sulfide molding material (glass fiber 30% by weight) was used in place of the polyetherimide molding material (glass fiber 30% by weight). The annealing treatment was performed at 170 ° C. for 1 hour.

The obtained multilayer pipe joint was tested for physical properties in the same manner as in Experimental Example 1, and showed good adhesion, no breakage, and no blisters.

Reference Example 1 A multilayer pipe joint was obtained in the same manner as in Experimental Example 1 except that a polyamide molding material (glass fiber 30% by weight) was used in place of the polyetherimide molding material (glass fiber 30% by weight).

When the physical properties of the obtained multilayer pipe joint were tested in the same manner as in Experimental Example 1, when the inner layer 1 had a thickness of less than 3 mm, the pipe was sometimes closed when a negative pressure was applied to the pipe.
Further, when the thickness of the inner layer 1 was less than 1 mm, blisters occurred in the hot water test for 3000 hours.

Reference Example 2 A multilayer pipe joint was obtained in the same manner as in Experimental Example 1 except that the polyacetal molding material (glass fiber 30% by weight) was used instead of the polyetherimide molding material (glass fiber 30% by weight).

When the physical properties of the obtained multilayer pipe joint were tested in the same manner as in Experimental Example 1, when the inner layer had a thickness of less than 3 mm, the pipe was sometimes blocked when a negative pressure was applied to the pipe.
Further, when the thickness of the inner layer was less than 1 mm, blisters occurred in the hot water test for 3000 hours.

Experimental Example 5 PEEK was used to make inner layer pellets, and polyetherimide was used to mix glass fibers in an amount of 30% to make outer layer pellets. PEEK was 50% by weight and polyetherimide was 50% by weight. Pellets for the intermediate layer were made with a molding material containing 10% by weight.

Injection molding was performed using each of the above pellets to form a pipe joint having a three-layer structure. The thickness of the intermediate layer 3 and the inner layer 1 was 1 mm. Next, after annealing at 180 ° C. for 1 hour to crystallize PEEK and leave it for 1 day, the adhesion portion of the outer layer 2 and the inner layer 1 of the multilayer pipe joint was cut off, and the adhesion strength of both layers was measured. The results are shown in Table 1.

Also, using the multilayer pipe joint obtained above, connect a pair of pipes as shown in FIG.
The adhesion strength between the outer layer 2 and the inner layer 1 was measured after 5000 hours. The results are shown in Table 1. At this time, the blockage state (blister) of the multilayer pipe joint was observed, but it was good.

Experimental Example 6 A multilayer pipe joint was prepared in the same manner as in Experimental Example 5, except that a molding material having 30% of glass fibers mixed with polysulfone phosphate was used instead of the molding material having 30% of glass fibers mixed with polyetherimide. Got

The physical properties of the obtained multilayer pipe joint were measured in the same manner as in Experimental Example 5. The results are shown in Table 1.

Incidentally, FIG. 2 shows another embodiment of the multilayer pipe joint, and in this embodiment, the concave groove 4 and the ring groove 5 formed around the inner layer 1 are formed substantially continuously. Also, the third
In the embodiment shown in the figure, a large number of convex portions 4a are formed on the bottom surface of the concave groove 4.

Further, as shown in FIG. 4, screw parts 10 may be provided at both ends of the outer periphery of the multilayer pipe joint so that the ends of the pipe 7 can be screwed into both ends of the multilayer pipe joint A.

As shown in FIG. 5, flanges are provided on both ends of the multi-layer pipe fitting A.
11 and the connecting part provided at the end of the pipe and the flange 11
Alternatively, bolts may be passed through the bolt holes provided with and nuts may be tightened.

(Effects of the Invention) The present invention comprises a polyether ether ketone or polyether nitrile as a main component whose inner layer that is in direct contact with a liquid is expensive but has extremely excellent heat resistance, hot water resistance, chemical resistance, abrasion resistance, corrosion resistance, etc. The outer layer is slightly inferior in heat resistance compared to polyetheretherketone and polyethernitrile, but is excellent in coloring, pressure resistance, weather resistance, impact resistance, etc. Since it is made of a material, it is possible to obtain a multilayer pipe joint satisfying each physical property while suppressing the cost as much as possible. Moreover, since each molding material can be molded by injection molding, it is possible to obtain a multilayer pipe joint with high productivity and stable quality.

INDUSTRIAL APPLICABILITY The multi-layer pipe joint of the present invention is extremely useful as a multi-layer pipe joint for piping in places where severe conditions such as high temperature water such as steam and chemicals are transported.

[Brief description of drawings]

1 is a sectional view of a multilayer pipe joint of the present invention, FIG. 2 is a sectional view of another embodiment of the multilayer pipe joint, FIG. 3 is a sectional view of yet another embodiment of the multilayer pipe joint, and FIG. And FIG. 5 is a cross-sectional view of a main part of still another embodiment of the multilayer pipe joint. 1 ... inner layer, 2 ... outer layer, 3 ... middle layer, A ... multilayer pipe joint.

Claims (1)

[Claims] 1. A pipe joint having a cylindrical inner layer in contact with a fluid and a cylindrical outer layer provided outside the inner layer, the pipe joint having a multilayer structure in the thickness direction formed of a molding material, A multi-layer pipe in which the inner layer is formed of a molding material containing polyether ether ketone or polyether nitrile as a main component, and the outer layer is formed of a molding material containing a resin other than polyether ether ketone or polyether nitrile as a main component. Fittings.