JPH08323884A - Pipe fitting made of fiber-reinforced resin - Google Patents

Abstract

PURPOSE: To provide a pipe fitting made of fiber-reinforced resin, which is provided with a water stopping layer on the inner surface thereof and capable of developing effectively excellent intrinsic resistance to internal pressure of the fiber reinforced resin, in the pipe fitting made of fiber-reinforced resin. CONSTITUTION: A pipe fitting is provided with a water stopping layer 2 at least on the internal surface of the socket thereof and the thick part thereof is formed of fiber reinforced resin while the thick part is formed of a fiber reinforced resin inner layer 3 of hoop winding enough to till the recessed parts 21a, 23a of the water stopping layer and the fiber reinforced resin outer layer 4 of helical winding on the inner layer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced resin pipe joint used for connecting internal pressure pipes.

[0002]

2. Description of the Related Art A pipe joint made of fiber reinforced resin has been attracting attention in order to increase the internal pressure resistance of the pipe joint. As such a fiber-reinforced resin pipe joint, one formed by the filament winding method is preferable in terms of production efficiency. When a fiber-reinforced resin pipe is used as an internal pressure pipe, microcracks (strictly speaking, the strength load of the fiber of the fiber-reinforced resin against the load is different for each fiber, and therefore the local interface between the fiber and the resin matrix Even if peeling or fiber breakage occurs, not material destruction), to prevent weeping (perspiration through microcracks), a water-stop layer such as vinyl chloride is used on the inner surface. It is rational to apply an injection-molded product of resin and to form a thick portion on the outer periphery by the filament winding method.

[0003]

However, in the fiber-reinforced resin pipe joint formed by the filament winding method, the water blocking layer is formed, and the fiber-reinforced resin thick portion is formed thereon by the filament winding method. However, according to the examination results of the present inventors, it is difficult to guarantee satisfactory internal pressure resistance.

That is, in the pipe joint, a groove, for example, a packing mounting groove exists on the inner surface of the receiving port, and a recess exists on the outer surface of the water blocking layer in correspondence with the groove, and the recess is formed by the filament winding method. Even if the fiber-reinforced resin thick portion of the water blocking layer is formed by hoop winding so as to be filled with the fiber-reinforced resin layer according to, the pressure resistance cannot be sufficiently exhibited.
If helical winding is applied instead of winding, it is difficult to completely fill the recesses of the water blocking layer with the fiber-reinforced resin, and it is disadvantageous to provide the water blocking layer.

An object of the present invention is to provide a fiber-reinforced resin pipe joint having a water-stop layer on the inner surface thereof and capable of effectively exhibiting the original excellent internal pressure resistance of the fiber-reinforced resin. It is to provide a pipe joint.

[0006]

A fiber-reinforced resin pipe joint according to the present invention is a pipe joint in which a water blocking layer is provided at least on an inner surface of a receiving port, and a thick portion is formed of fiber-reinforced resin. The thick wall portion is formed by a hoop-wound fiber-reinforced resin inner layer that only fills the recess of the water blocking layer, and a helically wound fiber-reinforced resin outer layer on the inner layer. The water blocking layer can be formed of a resin molded body or a fiber reinforced resin layer having a lower elastic modulus than the fiber reinforced resin inner layer.

The structure of the present invention will be described below with reference to the drawings. FIG. 1 shows a one-sided taper pipe joint as an example of the fiber-reinforced resin pipe joint according to the present invention. In FIG. 1, reference numeral 12 is a one-sided taper barrel portion, and 11 and 13 are receiving portions at both ends of the barrel portion. A packing mounting groove, a retaining ring mounting groove, and a pipe stopper tape are provided on the inner surface of each receiving portion. It has a surface.

Reference numeral 2 is a water stop layer on the inner surface of the pipe joint, and even if microcracks occur in the thick portion of the pipe joint, the microcracks do not propagate to the water stop layer and watertightness is guaranteed. , The occurrence of weeping is prevented. This water stop layer can be provided on the entire inner surface of the pipe joint, but it is provided only on the inner surface of the receiving port where microcracks are likely to occur (microcracks are likely to occur because of the corners where stress concentration occurs). Good.

No. 3 has a fiber winding angle on the water blocking layer of 90 ° ±
It is a fiber-reinforced resin inner layer of 5 ° (hoop winding) and is recessed portions 21a and 23a of the water blocking layers 21 and 23 of the receiving portions 11 and 13, respectively.
(Existing in correspondence with the packing mounting groove, etc., for example,
For joints with a diameter of φ50, a depth of about 7 mm. Caliber φ
In the case of 200 joints, the minimum thickness is sufficient to fill the depth of about 20 mm), and this inner layer is not substantially present on the flat surface between the recesses. However, since the fibers are continuous, as a result of the fibers passing over the flat surface on the continuous hoop winding, a slight hoop winding layer is unavoidably formed on the flat surface, Its thickness is no more than about 10 μm (thus, the thickness of the inner layer is 10 μm or less).
μm and over the maximum thickness of 20 mm above). Also, the fiber-reinforced resin inner layer formed by hoop winding of the body portion 12 between the both end receiving portions 11 and 13 is the minimum formed when the filament winding of one receiving opening is transferred to the filament winding of the other receiving opening. Is the thickness of.

Reference numeral 4 is an outer layer of fiber reinforced resin having a fiber winding angle of 20 ° to 70 ° (helical winding) on the inner layer 3 of fiber reinforced resin, and the thickness thereof is usually 0.5 mm at the minimum portion.
The maximum part is about 15 mm. The water stop layer, even if micro cracks occur in the thick portion of the pipe joint,
As long as the watertightness is ensured without the propagation of microcracks to the water stop layer, a resin molded product can be used, for example. Further, even with a fiber-reinforced resin, a fiber-reinforced resin layer having a lower elastic modulus than that of the fiber-reinforced resin inner layer and capable of elastically absorbing the stress which is a source of microcracks can be used.

In FIG. 1, resin moldings are used for the water blocking layers 21 and 23 on the inner surfaces of the receiving portions 11 and 13, and a fiber reinforced resin having a low elastic rate is used for the water blocking layer 22 inside the body 12. are doing. Resin moldings include vinyl chloride resin, polyethylene, polycarbonate, ABS resin, polypropylene,
Thermoplastic resins such as acrylic resins, polyester resins, epoxy resins, phenolic resins and other thermosetting resins, as well as fillers such as calcium carbonate and aluminum hydroxide, short fibers (glass fibers, carbon fibers, etc.). ) Added injection molded products, vacuum molded products, pipe shaped products,
In the case of blow molded products and thermosetting resins, resin injection molded products can be used, and when high dimensional accuracy is required, injection molded products, vacuum molded products and pipe shaped products can be used. preferable.

The low elastic modulus fiber reinforced resin includes chopped strand mat, surface mat, non-woven fabric, stretchable fiber material (knitted, elongation rate 5 to 100%, elongation recovery rate 60% or more. It is preferable to use a non-woven fabric or a stretchable fibrous material because the non-woven fabric or the stretchable fibrous material fits well to unevenness, and a tape-shaped one is preferable. It is convenient because a water stop layer can be formed by winding.

As the material of the reinforcing fibers of the fiber-reinforced resin of the inner layer and the outer layer and the fiber-reinforced resin of low elastic modulus, glass fiber,
Examples include inorganic fibers such as carbon fibers, aramid fibers, and organic fibers such as polyethylene terephthalate fibers. Examples of the resin include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin, and phenol resin. In addition to these thermosetting resins, photocurable resins can be used.

The volume content of fibers of the fiber-reinforced resin in the inner and outer layers is usually 55 to 67%. Needless to say, the fiber-reinforced resin pipe joint according to the present invention is not limited to the above-mentioned straight pipe joint, but it is a bend pipe joint or a T-shaped pipe joint (chees pipe) as shown in FIG. And flanged teeth).

In FIG. 2, 2 is a water stop layer provided on the entire inner surface of the joint, 3 is a hoop-wound fiber reinforced resin inner layer having a thickness sufficient to fill the recesses of the water stop layers 21 and 23 on the inner surface of the receiving port, Reference numeral 4 denotes a helically wound fiber-reinforced resin outer layer on the inner layer 3. T
In a shaped pipe joint, when a water blocking layer is provided on a surface other than the inner surface of the receiving port, the water blocking layers 21 and 23 on the inner surface of the receiving port are formed of a resin molded body, or the above-described stretchable fiber material or nonwoven fabric is used as a reinforcing fiber. The other part 22 is wrapped with a chopped strand mat, and the remaining space (the above unwoundable part) is covered with a resin impregnated roving cloth. It is possible to form a water blocking layer in another portion.

FIG. 3 shows an outline of a usual filament winding apparatus used in the production of the fiber reinforced resin pipe joint according to the present invention. The roving is drawn out from the bobbin 51, and the roving is impregnated with a resin tank 52. At, the curable resin is impregnated, and this curable resin impregnated roving is wound and laminated on the rotating mandrel 50 via the feed eye 53. The mandrel 50 has high rigidity and is lightweight, for example, metal products such as steel, stainless steel, aluminum and duralumin, rubber materials such as urethane, blow molded products such as polypropylene and polyethylene, polyamide,
A machined product such as high-density polyethylene can be used.

In the feed eye 53, in addition to the forward and reverse running in the X-axis direction parallel to the rotation axis of the mandrel 50, the X-axis can be used in order to cope with the complicated movement of the mandrel during the manufacture of the T-shaped pipe joint. Forward / reverse traveling in the Y-axis direction, forward / reverse traveling in the Z-axis direction, forward / reverse rotation in a plane perpendicular to the Z-axis (U
Motion) and forward / reverse rotation (W motion) in a plane perpendicular to the Y axis are possible. An AC servomotor is usually used to control the traveling and rotation of these. As a control method, a feedback method using a proximity switch or the like, or a teach-in playback method in which a computer controls a moving coordinate in advance according to a program are used. It is sufficient if the control accuracy is within 1 mm.

FIGS. 4 (a) to 4 (c) show a process of manufacturing the one-sided taper pipe joint shown in FIG. 1 according to the present invention. In FIG. 4A, 50 is a mandrel, 21 and 23 are resin moldings for the water blocking layer in the receiving port, and 54 is a pin ring. In order to manufacture the above-mentioned one-sided taper pipe joint, as shown in FIG.
23 is attached and the pin ring 54 is further attached. Furthermore,
A waterproof layer 2 of a low elastic modulus fiber reinforced resin is formed on the outer surface of the central body of the mandrel 50 by a resin-impregnated chopped strand mat, surface mat, non-woven fabric, elastic fiber material, or the like.
Mold 2.

Next, as shown in FIG. 4B, the feeding eye 53 is reciprocally moved in the X-axis direction, and the lobing is hooked on the pin ring 54 at the time of folding back, so that the resin-impregnated roving is floated. Winding, resin molding 21,2
The fiber-reinforced resin inner layer 3 having a depth enough to fill the concave portion 3 is formed. In this case, the running of the feeding eye is controlled on the flat surface between the concave portions of the resin molded body, and the roving is not wound, and the winding angle of the hoop winding is set to about 90 ° ± 5 °. .

Next, as shown in FIG. 4C, the feed eye is reciprocally moved in the X-axis direction, and is rolled back at the time of folding.
The resin impregnated roving is helically wound by hooking the bing on the pin ring 54 to form the fiber-reinforced resin outer layer 4 having a predetermined thickness. In this case, the winding angle is ± 5
It is preferable that the angle is 0 ° to ± 65 ° (this winding angle is also preferable in the case of a bend joint. On the other hand, in the case of a T-shaped pipe joint, at this winding angle, the extension of the central vertical pipe portion is taken over the winding wire. Since it is not possible, it is appropriate to make a two-layer winding of ± 20 ° to ± 35 ° and ± 60 ° to ± 75 °.).

After molding the thick portion of the pipe joint in this way, the uncured semi-finished product is carried into a heating furnace together with the mandrel, the resin is cured, and the mandrel is demolded from this cured product, Trimming is performed, and the production of the single-sided taper pipe joint shown in FIG. 1 is completed. In the above, in the fiber winding, several rovings (about 10) are aligned and wound, and the tension is 0.5 to 2.5 in order to guarantee the mechanical strength by using the fiber reinforced resin body as the voidless.
It is suitable to set it to 1 kg / piece.

The fiber volume content of the fiber reinforced resin (inner layer and outer layer) is preferably 55% to 67% from the viewpoint that voids are small and stable quality (predetermined tensile strength and bending strength) is obtained. . As described above, in the invention of claim 1, the fiber winding angle in the fiber-reinforced resin inner layer is 90.
The thickness is 0.5 mm to 15 mm at ± 5 °, the fiber winding angle in the fiber reinforced resin outer layer is 20 ° to 70 °, the thickness is 0.01 mm to 20 mm, and the fiber volume content in the entire fiber reinforced resin inner layer and outer layer is 55% to 67% is particularly preferable for achieving the object of the present invention.

[0023]

Since the inner layer of the fiber-reinforced resin in the form of a hoop is provided on the water blocking layer, the recess of the water blocking layer portion on the inner surface of the receiving port is completely filled with the fiber reinforced resin so that the inner surface of the pipe joint is covered with the water blocking layer. Can be closely attached. Furthermore, the thickness of the fiber-reinforced resin inner layer is set to the minimum thickness for filling the recess of the pipe joint, and the thick part of the pipe joint is formed of the fiber-reinforced resin of helical winding as thick as possible.
As is clear from the results of the internal pressure resistance test of Examples and Comparative Examples described below, the internal pressure resistance can be effectively exhibited.

[0024]

【Example】

[Example 1] The product has a nominal diameter of 150-75 and a taper angle of 1
3 is a one-sided taper pipe joint shown in FIG. 1 at 3 °. For the resin, an unsaturated polyester resin liquid consisting of 100 parts by weight of an ortho unsaturated polyester (containing about 40% styrene and 6% cobalt naphthenate) and 0.7 parts by weight of methyl ethyl ketone peroxide (curing agent) was used as a fiber. Is glass fiber
Bings (counting 4500 g / km) were prepared by aligning 10 pieces each.

A vinyl chloride resin molded body was attached to both ends of the mandrel, and a resin-impregnated glass expansion tape (stretching rate 36%, stretching recovery rate 87%, width 100 m) was mounted on the central body of the mandrel.
m, basis weight 31 g / m) to form a waterproof layer by winding two layers, and resin-impregnated roving is loop-wound with a thickness sufficient to fill the recesses of the vinyl chloride resin molded body, and further resin-impregnated lobe The bing is helically wound at a winding angle of about 60 ° so that the thickness is 3 mm on the side of the bore 150 (the fiber volume ratio of this helical winding layer is 62%), and then the resin is cured at 70 ° C. for 1 hour to remove the mold. did.

[Example 2] As the mandrel, a mandrel having concave and convex surfaces for molding the inner surface of the mouth is used, and the glass expansion tape (stretching rate) used in the first embodiment is formed in the inner surface molding portion of the mouth. 36%, extension recovery rate 87%, width 100 mm, basis weight 31 g / m) to form a water blocking layer only in the receiving port, and under other conditions (resin impregnated roving hoop winding, resin impregnated lobe). Bing helical winding, curing conditions, etc.) were the same as in Example 1.

[Comparative Examples 1 and 2] In order to make the outer diameter of the thick portion of the pipe joint the same as that of the above-mentioned embodiment, the thick portion (portion other than the water blocking layer) of the thick portion is made of resin impregnated roving flap. -The same as Example 1 and Example 2 except that it was formed only by wrapping.
For each of the above-mentioned example product and comparative example product, a hard vinyl chloride pipe was connected to both ends of the pipe joint so as to withstand a thrust load (cross-sectional area in the pipe x internal pressure) based on the internal pressure, and an internal pressure resistance test was conducted. , 60 kg / cm for the example product
There was no abnormality even in ² , whereas the comparative example product was 25 kg
The pipe joint was damaged by an internal pressure as low as / cm ² .

Further, 20 kg / cm ² pressure-internal pressure 0 is 1
When a hydraulic fatigue test using a cycle was performed, 100,000 cycles passed without any abnormality in the example product, but 5000 cycles or less in the comparative example product. [Example 3] The product is a bend pipe joint having a nominal diameter of 150 and a bend angle of 45 °.

The same resin and roving as in Example 1 were used. Mounting of vinyl chloride resin moldings on both ends of the bending mandrel and resin-impregnated glass expansion tape at the center of the mandrel (expansion rate 36%, extension recovery rate 87%, width 100 mm, basis weight 31 g / similar to Example 1). m) to form a water blocking layer by two-layer winding, and resin-impregnated roving is hooped with a thickness sufficient to fill the concave portion of the vinyl chloride resin molded product, and also hooped to the center of the mandrel. Is applied with a thin uniform thickness (2 mm), and the resin-impregnated roving is helically wound at a winding angle of about 60 ° so that the minimum thickness is 3 mm (water stop layer at the center of the mandrel, hoop winding). And the volume ratio of the helically wound fiber was 60%), and then the resin was cured at 70 ° C. for 1 hour and demolded.

[Embodiment 4] The product is a bend pipe joint having the same nominal diameter 150 as in Embodiment 3 and a bend angle of 45 °. As the bending mandrel, one having concave and convex surfaces for forming the inner surface of the mouth is used at both ends, and a glass expansion tape (expansion rate 36%, extension recovery rate 87%, width 100 m is used for the inner side molding part of the mouth.
m, basis weight 31 g / m) to form a water blocking layer only within the receiving port, and other conditions (resin-impregnated roving hoop winding, resin-impregnated roving helical winding, curing conditions, etc.)
Was the same as in Example 3.

[Comparative Examples 3 and 4] In order to make the outer diameter of the thick portion of the pipe joint the same as that of the third and fourth embodiments, the thick portion (portion other than the water blocking layer) was impregnated with resin. Same as Examples 3 and 4 except that molding was performed only by hoop winding of a bing. When the internal pressure resistance test was conducted on each of the above-mentioned Example products 3 and 4 and Comparative example products 3 and 4, there was no abnormality at 60 kg / cm ^{2 in the} Example products 3 and 4, whereas the comparative product No. 3 was 15 kg / cm ² , and Comparative Example 4 was 12 kg / cm ² , and the pipe joint was damaged by a low internal pressure.

Further, when a hydraulic fatigue test was carried out, 100,000 cycles were passed without any abnormality in Examples 3 and 4, but about 80,000 cycles in Comparative Examples 3 and 4. [Example 5] The product is a cheese pipe joint having a nominal diameter of 150 x 75.

The same resins and rovings as in Example 1 were used. Watertightness is achieved by mounting vinyl chloride resin moldings on each of the three ends of the T-shaped mandrel, winding a resin-impregnated chopped strand mat around the center of the mandrel crossing, and pasting a resin-impregnated roving cloth around the unwoundable portion. The layer is molded and left to stand for 20 minutes to semi-cure the water blocking layer, and then the resin-impregnated roving is wound in a hoop with a thickness sufficient to fill the concave portion of the vinyl chloride resin molded body, and a surface having no unevenness. The resin impregnated roving to a thickness of 5 m
Helical winding with a wrap angle of about 60 ° so that the fiber volume ratio of this helical wound fiber reinforced resin is 62
%), And then the resin was cured at 80 ° C. for 2 hours and demolded.

The setting of the tube axis of the T-shaped mandrel during winding was done manually. [Sixth Embodiment] The product is the same pipe joint as in the fifth embodiment. In contrast to Example 5, instead of mounting the vinyl chloride resin molded body on each of the three ends of the T-shaped mandrel, a resin-impregnated glass expansion tape (extension rate 36%, extension recovery rate 87%, width 100).
mm, basis weight 31 g / m)
Same as Example 5.

[Comparative Examples 5 and 6] In order to make the outer diameter of the thick portion of the pipe joint the same as that of the above-mentioned Examples 5 and 6, the thick portion (portion other than the water blocking layer) was impregnated with resin. Same as Examples 5 and 6 except that only the hoop winding of the bing was used. When an internal pressure resistance test was conducted on each of the above-mentioned example products 5 and 6 and comparative example products 5 and 6, there was no abnormality at 60 kg / cm ^{2 in the} example products 5 and 6, whereas in the comparative example product No. 5 was 12 kg / cm ² , and Comparative Example 6 was 10 kg / cm ² , and the pipe joint was damaged by a low internal pressure.

[0036]

The fiber-reinforced resin pipe joint according to the present invention has a water stop layer for preventing weeping,
The fiber-reinforced resin thick portion is constructed so as to exert its original excellent internal pressure resistance against the water stop layer, and excellent anti-weeping and internal pressure resistance can be guaranteed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a fiber-reinforced resin pipe joint according to the present invention.

FIG. 2 is a sectional view showing another example of the fiber-reinforced resin pipe joint according to the present invention.

FIG. 3 is an explanatory view showing a filament winding apparatus used for manufacturing a fiber-reinforced resin pipe joint according to the present invention.

FIG. 4 is an explanatory view showing a manufacturing process of the fiber-reinforced resin pipe joint according to the present invention, in which (a) of FIG. 4 is immediately after the formation of the water blocking layer and (b) of FIG. Immediately after molding the inner layer,
FIG. 4C shows each of the fiber-reinforced resin inner layers immediately after being molded.

[Explanation of symbols]

 2 Water-stop layer 21a Water-stop layer recess 23a Water-stop layer recess 3 Fiber-reinforced resin inner layer 4 Fiber-reinforced resin outer layer

Claims (1)

[Claims] 1. A pipe joint in which a water blocking layer is provided at least on an inner surface of a receiving port, and a thick portion is formed of a fiber reinforced resin, and a hoop winding is sufficient to fill a recess of the water blocking layer. A fiber-reinforced resin pipe joint characterized in that the thick portion is formed by a fiber-reinforced resin inner layer and a helically wound fiber-reinforced resin outer layer on the inner layer.