JPH0760852A - Pipe joint made of fiber-reinforced resin and its manufacture - Google Patents

Abstract

PURPOSE:To provide a pipe joint made of FRP, capable of ensuring excellent resistance to weeping and the dimentional accuracy or smoothness of an inner face and provide the manufacture of the same at a low cost. CONSTITUTION:In a pipe joint made of fiber-reinforced resin, a short pipe-like resin- molded product 10 is fixed to an inner face of at lease one receiving port from the inlet of the receiving port through the rear side thereof, and the material of a fiber- reinforced resin portion 21 facing the outer face at the end on the rear side of the molded product 10 is made of a material which hardly causes sags and runs of resin in an uncured state rather than that of other fiber-reinforced resin portions 22. At least one end of a rotary core 35 is overlaid with a short pipe-like resin-molded product member 1, and a fiber face material 210 impregnated with a curable resin having high viscosity is wound around a boundary portion between the outer face at the end on the rear side of the molded product member and the outer face of the core. Then, a curable resin-impregnated continuous fiber material 220 is wound around and laiminated on the short pipe-like resin-molded product and the core and, furthermore, the resin impregnated in the face material and the resin impregnated in the continuous fiber material are cured by heating and, thereafter, the cured pipe joint is released from a mold.

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 joining a high internal pressure pipe such as a water pipe and a method for producing the pipe joint.

[0002]

2. Description of the Related Art In a fiber reinforced resin pipe joint (hereinafter, fiber reinforced resin is referred to as FRP), in addition to the corrosion resistance and light weight of the synthetic resin pipe joint, excellent internal pressure (tensile) strength and impact It has strength and the like.

In this FRP pipe joint, a continuous pipe impregnated with a resin is wound around and laminated on a mandrel, and after the resin is cured, the mandrel is released from the mold, that is, a filament winding method (hereinafter referred to as FW). In the FRP pipe joint molded by
It can effectively bear the stress and has a high internal pressure strength.

However, the FW method FRP pipe joint is
When used under high pressure, especially under pulsating load conditions, for example, when used as a pipe joint for a water pipe, a phenomenon that internal water leaks in a sweating manner, that is, a weeping phenomenon is likely to occur.

In order to prevent such a weeping phenomenon, a synthetic resin molding formed by blow molding of polyvinyl chloride or the like is fixed to the entire inner peripheral surface of the FRP pipe joint,
It is known to use this synthetic resin molded body as a weeping prevention layer (JP-A-60-229742).

[0006]

In the pipe joint, for pipes having the same diameter, there are many types of pipes having different shapes such as a straight pipe joint (socket), a bend pipe joint, a T-shaped pipe joint, and a cross-shaped pipe joint. Things are needed.

Therefore, in the above-mentioned conventional example, it is necessary to mold many kinds of molded products made of resin according to the kind of the pipe joint, many kinds of blow molding dies are required, and the manufacturing cost is high. It is costly and management of blow molded products is difficult.

By the way, an ordinary FRP pipe joint
Observing the ping phenomenon, the location of the weeping
There are many parts where the pipe insertion port is inserted, that is, the reception port, especially the taper step surface at the back of the reception port, the rubber ring mounting groove for water stop, the retaining ring mounting groove position, etc. At the central portion of the inner surface of the pipe joint where there is no contact therewith, weeping is hardly observed.

This is because local stress due to contact with the tip of the pipe insertion port, stress concentration at uneven portions such as grooves under the action of high internal pressure,
Or, due to local stress due to the contact of the retaining ring, etc., initial microcracks occur at those locations,
It can be inferred that these microcracks propagate in a chain so as to connect the interface between the resin and the fiber.
Even if the weeping prevention layer is provided on the entire inner surface of the pipe joint, the weeping prevention layer portion at the center of the inner surface of the pipe joint, which does not come into contact with the insertion opening, can contribute almost to the prevention of weeping. Absent.

In the above-mentioned conventional example, a weeping-preventing synthetic resin molded body by blow molding is used as a mandrel of the FW, and the demolding work from the mandrel in the usual FW method is omitted, and the molding time is reduced. Although we are trying to shorten the cost, it is necessary to manage the blow molding cost of various types of weeping prevention synthetic resin moldings (particularly the die cost) and the management of many types of weeping prevention synthetic resin moldings. Considering the cost required, it is difficult to deny the cost increase.

An object of the present invention is to reduce the cost of various types of joints having the same diameter, that is, straight pipe joints, bend pipe joints, T-shaped pipe joints, cross-shaped pipe joints, etc., and to obtain excellent weeping resistance. Another object of the present invention is to provide a pipe joint made of FRP and a method for producing the same, which guarantees inner surface dimensional accuracy and inner surface smoothness.

[0012]

A fiber-reinforced resin pipe joint according to the present invention is a pipe joint made of a fiber-reinforced resin, in which at least one socket inner surface has a short tubular resin molded body extending from the socket inlet to the inner side. It is characterized in that the material of the fiber reinforced resin portion that is fixed and faces the outer surface of the back end of the molded body is less likely to cause resin dripping in an uncured state than other fiber reinforced resin portions. It is a composition.

In the method for manufacturing a fiber-reinforced resin pipe joint according to the present invention, at least one end of the rotary core mold is covered with a short tubular resin molded body member, and the outer surface of the inner end of the molded body member and the outer surface of the core mold are separated from each other. The boundary portion is wound with a fiber surface material impregnated with a high-viscosity curable resin, and then the curable resin-impregnated continuous fiber material is wound and laminated on the short tubular resin molded body and the core die, and further heated by the above. The constitution is characterized in that the impregnating resin for the face material and the impregnating resin for the continuous fiber material are cured, and then the cured body is demolded.

The structure of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a short tubular resin molded member 1 used in the present invention, which has a shape corresponding to the inner surface shape of a pipe joint receiving port, and in the illustrated example, a straight portion forming the inner surface of the tip of the receiving port. Groove 1 for housing 11 and rubber ring
2, a groove portion 13 for accommodating the retaining ring, a sleeve portion 14 for receiving the distal end portion of the tube insertion opening, and a trimmed portion 15.

FIG. 2 shows an example of the FRP pipe joint according to the present invention, in which the short tubular resin molded body 10 is fixed to the inner surface of the receiving port,
The fiber-reinforced resin portion 21 facing the outer surface of the inner end of the short tubular resin molded body 10 is made of a material that does not easily sag when the fiber-impregnated resin is uncured, and is usually formed by manual winding. ing. The other fiber reinforced resin portion 22 is formed by winding and laminating a resin-impregnated continuous fiber material by the FW method. On the other hand, the fiber-reinforced resin portion 21 that faces the outer surface of the distal end portion of the short tubular resin molded body 10 can be formed by using a fiber surface material as the reinforcing fiber, as described later. Of course, other curable resin-impregnated fibrous materials that hardly cause resin dripping when uncured can be used.

FIG. 3 schematically shows a general FW apparatus used in the method for manufacturing a pipe joint of the present invention, in which the continuous fiber material drawn out from the bobbins 31 ,. Further, it is converged into a band shape by the feed eye 34 and then wound around the core die 35. During this time, the feed eye 34 is rotated at a speed corresponding to the winding pattern of the resin-impregnated continuous fiber material. Direction (X-axis direction), the Y-axis direction with respect to the X-axis direction, and the Z-axis direction, the core die 35 is rotated.

To manufacture the FRP pipe joint shown in FIG. 2 by the manufacturing method of the present invention, first, in FIG.
Short tubular resin molded member 1 is attached to both ends of 5 through spacers 4 as shown in FIG. 4 (a), and then resin dripping is caused as shown in FIG. 4 (b). A fibrous surface material 210 impregnated with a hard highly viscous curable resin is wound around the boundary portion between the outer surface of the inner end of the short tubular resin molded member 1 and the surface of the core die 1.

After that, the continuous fiber material drawn out from the bobbin 31 in FIG. 3 is passed through the resin impregnation tank 32 in a dipped state, and further passed through the feed eye 34 to converge into a band shape, which corresponds to the winding pattern. The core die 35 is rotated at a constant speed and the feed eye 34 is moved in the axial direction (X-axis direction) of the core die and in the Y direction.
The resin-impregnated continuous fiber material 220 from the feed eye 34 is made to reciprocate in the axial direction, and as shown in FIG. In a plurality of layers, each layer is wound at a predetermined winding angle.

When the resin-impregnated continuous fiber material is wound and laminated in a predetermined amount in this manner, the wound laminated body is carried into the heating furnace together with the core die, and the fiber face material is impregnated with the resin and the continuous fiber material is impregnated with the resin. Is cured, and the cured product is demolded from the core mold while the short tubular resin molded member is integrally fixed, and both ends are trimmed,
This completes the manufacture of the FRP pipe joint shown in FIG.

In the above, it is unavoidable that a slight gap (usually, a gap of about 1 mm) is formed between the inner end of the short tubular resin molded member and the core die. Therefore, since the fiber reinforced resin portion (21 in FIG. 2) facing this gap is formed by winding a fiber face material impregnated with a highly viscous curable resin that hardly causes resin dripping when uncured, Before the resin curing step, it is possible to prevent the uncured resin from dripping and flowing into the short tubular resin molded body member 1 through the above-mentioned gap, and therefore, it is possible to prevent the resin from sticking to the inner surface of the short tubular resin molded body of the FRP pipe joint. it can. Further, a fiber reinforced resin portion other than the fiber reinforced resin portion facing the inner end of the short tubular resin molded member 1 (22 in FIG. 2).
On the other hand, a resin having a low viscosity when uncured can be used as the impregnating resin, and the FW method can ensure good impregnating workability of the resin and ensure good workability.

The impregnating curable resin of the fiber reinforced resin portion 21 facing the inner end of the short tubular resin molded member is an epoxy resin, an unsaturated polyester resin, a vinyl ester resin,
A phenolic resin or the like, which has excellent adhesiveness to a short tubular resin molded body, and is usually 1000 cp to 3000 c at 25 ° C.
Those within the range of p are used. Kashidashi, 1000
Below cp, it is difficult to prevent the above resin dripping flow.
If it is 000 cp or more, it becomes difficult to impregnate the fiber surface material with the resin. In order to set the resin viscosity at 25 ° C. to a high value within such a range, use a thermosetting resin that falls within the range where the resin itself has a viscosity at 25 ° C. Add a thickener to the resin Alternatively, a method of blending a resin with a filler can be used.

In this case, the thickener used in the method (1) has a property of chemically binding to the thermosetting resin to form a linear or partial cross-linking and increasing the viscosity by increasing the molecular weight. , For example, toluylene diisocyanate
, Metal alkoxides such as aluminum isopropoxide and titanium tetrabutoxide, divalent metal oxides such as magnesium oxide and calcium oxide and beryllium oxide, and divalent metal hydroxides such as calcium hydroxide. And amines such as hexamethylenediamine.

As the filler used in the method (1), calcium carbonate, magnesium carbonate, barium sulfate, talc, mica, alumina, glass powder, aerosil (microfiber), aluminum hydroxide, magnesium hydroxide, cold water stone. , Silica sand, resin crushed pieces, gel coat chips and the like, and the addition amount, particle size and the like are determined in consideration of the set viscosity, economy, workability, product strength and the like.

As the fiber face material of the fiber reinforced resin portion 21 facing the inner end of the short tubular resin molded body member, any suitable resin can be used as long as it has resin retention property. Polyester fiber, polyamide fiber , Organic fibers such as aramid fibers,
Woven fabrics using inorganic fibers such as glass fibers and carbon fibers (for example, roving cloth, glass fit tape, etc.), non-woven fabrics (for example, matted with needle punch or stitch bond, with an appropriate binder It is preferable to use a bundle of fibers).

As the impregnating and hardening resin for the fiber reinforced resin portion 22 other than the fiber reinforced resin portion 21 facing the inner end of the short tubular resin molded member, epoxy resin, unsaturated polyester resin, vinyl ester resin, pheno resin is used. A resin having a low viscosity suitable for the FW method and having excellent adhesiveness to the short tubular resin molded body is used. It is preferable to use the same kind of resin as the resin of the fiber-reinforced resin portion 21 facing the inner end of the short tubular resin molded member described above. As the continuous fiber material of the fiber reinforced resin portion 22 other than the fiber reinforced resin portion 21 facing the far side end of the short tubular resin molded member, inorganic fiber such as glass fiber or carbon fiber, or aramid fiber, polyester fiber or polyamide fiber is used. And the like, and the content ratio of the continuous fiber material in the fiber reinforced resin portion is set by the allowable internal water pressure, the allowable external pressure, and the wall pressure of the pipe joint.

The short tubular resin molded member used in the present invention is required to have a dense resin structure, and its molding is carried out by a vacuum molding method (using a plastic plate original fabric in a vacuum molding die). Then, perform vacuum suction molding under heating to cut the end surface of the molded product), blow molding method (expand the ballison from the extruder to mold with a blow molding die, and cut the end surface of the molded product) or Although an injection molding method or the like can be used, it is preferable to use an injection molding method or a vacuum molding method having excellent inner diameter dimensional accuracy in order to ensure dimensional accuracy when inserting the tube insertion port into the tube receiving port. In particular, the short tubular resin molded body member illustrated in FIG. 1 has an undercut, so it is necessary to use a split mold. In order to form a short tubular resin molded body member having this undercut by, for example, a vacuum forming method, a metal mold 5 having a split structure as shown in FIG. This mold is brought into contact with the plate, and the softened plastic plate 51 is suctioned and adhered to the surface of the mold 5 by vacuuming the inside mold passage, as shown in FIG. In addition, the central piece of the split mold 511 is removed, then the opposing pieces 512 and 512 are removed, and finally the opposing pieces 513 and 513 are removed, and both ends of the molded body are removed as shown in FIG. As shown in (c), it is cut, and the molding of the short tubular resin molded member 1 is completed.

As the resin of the short tubular resin molded member 1, any resin can be used as long as it can be molded into the shape of the inner surface of the pipe fitting receptacle, and specifically, epoxy resin, unsaturated polyester, vinyl ester resin, Thermosetting resin such as phenol resin, polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polystyrene, polycarbonate
And thermoplastic resins such as polyamide, polyvinylidene fluoride, polyphenylene sulfide, polysulfone, and polyether ether ketone. If necessary, additives such as fillers, low-shrinking agents, heat stabilizers, plasticizers, lubricants, antioxidants, modifiers, short fibers, and pigments can be added to these resins. Further, in order to secure the adhesiveness with the fiber reinforced resin, it is preferable to apply an adhesive or a surface treatment agent to the outer surface of the short tubular resin molded member, and the adhesive or the surface treatment agent may be an unsaturated polyester. Examples thereof include epoxy-based, urethane-based, vinyl ester-based, and the like, and it is most preferable to use a solvent-volatile one-component urethane surface-treating agent from the viewpoint of adhesive strength, coating workability, and the like.

In the above example of the FRP pipe joint,
Although only the fiber reinforced resin portion facing the outer surface of the inner end of the short tubular resin molded body 1 is formed of the fiber face material impregnated with the high-viscosity curable resin, as shown in FIG. It is also possible to form the portion 211 over the entire exposed inner surface portion with a fiber surface material impregnated with a high-viscosity curable resin. In this portion 211, since the mold has a flat outer surface and the orientation state of the fibers of the continuous fiber reinforced resin portion 22 is particularly good, the reinforcing effect of the fibers of the continuous fiber reinforced resin portion 22 formed by the FW method is exerted. In the face material fiber reinforced resin portion 211, the fiber content can be made extremely effective, so that the fiber content should be low, and the resin content should be high to make it a layer that is soft and easy to stretch, and has improved crack resistance against water pressure pulsation. Is preferred. (The resin content is in the range of 30 to 95% by volume. Below 30% by volume, there is no effect,
If the content is 95% by volume or more, resin dripping occurs during lamination).

[0029]

Function: A curable resin-impregnated fiber material that hardly causes resin dripping is wound around a boundary portion between the short tubular resin molded body 1 and the core die 35, and then a fiber reinforced resin layer is formed on the whole by the FW method. Therefore, it is possible to prevent the resin from dripping into the short tubular resin molded body.

Further, the tip of the pipe insertion portion from the inlet to the inner end of the receiving port is brought into contact, the rubber ring for preventing water and the retaining ring are brought into contact with the inner surface of the receiving port, and the groove uneven surface is distorted by internal pressure. On the other hand, in the short tubular resin molded body 10, the generation of initial microcracks is suppressed, and the generation of weeping is well prevented.

Further, as shown in (a) to (d) of FIG. 7, under the same diameter, a straight pipe joint, a bend pipe joint,
The short tubular resin molded body 10 can be commonly used for many types of pipe joints such as T-type pipe joints and cross-type pipe joints.

[0032]

EXAMPLE According to the present invention, it is possible to obtain an FRP pipe joint having excellent inner surface dimensional accuracy, inner peripheral smoothness and weeping resistance, which is compared with the following example and comparative example. You can also check by.

Example 1 The construction and dimensions of the FRP pipe joint in this example is a straight pipe joint for a water pipe having a diameter of 150 mm.
As shown in FIG. 2, only the fiber reinforced resin portion 21 facing the outer surface of the distal end of the short tubular resin molded body 10 is formed by manual winding with a high viscosity resin-impregnated fiber face material, and the other fiber reinforced resin portions 22 are low viscosity resin. The impregnated continuous fiber material is formed by the FW method.

As the short tubular resin molded product, a product in which a vinyl chloride resin sheet having a thickness of 3 mm was molded by the illustrated vacuum molding and the outer peripheral surface was coated with a urethane surface treating agent was used. For continuous fiber material, glass fiber roving (count 22
(30 g / km) 10 bundles are used and the impregnating resin is unsaturated polyester resin (ortho type) 100
Parts by weight and curing agent (methyl ethyl ketone peroxide)
0.8 parts by weight and curing accelerator (6% cobalt naphthenate)
A formulation consisting of 0.3 parts by weight was used.

A glass phyto-tape (width 100 mm) having a basis weight of 31 g / m ² was used as the fiber surface material, and the unsaturated polyester resin (ortho type) 1 was used as the high-viscosity impregnated resin.
00 parts by weight, a curing agent (methyl ethyl ketone peroxide) 0.8 parts by weight, a curing accelerator (6% cobalt naphthenate) 0.3 parts by weight, and a filler (calcium carbonate having an average particle size of 8 μm) 100 parts by weight. A formulation having a viscosity of approximately 1843 cp at 25 ° C. was used.

The high-viscosity resin-impregnated fiber face material is wound manually
The impregnated continuous fiber material is used for running the feed eye by the FW method.
While controlling not only the core type axial direction but also the Y direction in FIG.
90 ⁰And ± 60⁰It was wound at an angle of.

Curing was performed at 50 ° C. for 2 hours. Example 2 In contrast to Example 1, a polyester nonwoven fabric (width 100 mm) having a basis weight of 200 g / m ² was used as the fiber surface material, and the high-viscosity impregnated resin was an unsaturated polyester resin (ortho type).
100 parts by weight, curing agent (methyl ethyl ketone peroxide) 0.8 parts by weight, curing accelerator (6% cobalt naphthenate) 0.3 parts by weight, and thickener (magnesium oxide) 10
A viscosity of about 2230c at 25 ° C consisting of 0 parts by weight.
Same as Example 1 but using p formulation.

Example 3 The procedure of Example 1 was repeated except that the high-viscosity resin-impregnated fiber face material was wound over the entire area 211 between the outer surfaces of the distal end portions of both short tubular resin moldings as shown in FIG. Same as Example 1.

Comparative Example The same as Example, except that the winding of the high-viscosity resin-impregnated fiber face material was omitted and the resin-impregnated continuous fiber material was wound over this omitted portion.

Regarding the above-mentioned example product and comparative example product,
When the presence or absence of resin adhesion on the inner surface of the short tubular resin molded body was investigated, the resin was adhered in the comparative example product, but the resin adhesion was not observed in the example product, and the inner diameter dimensional accuracy was measured. However, in the example product, the accuracy of the inner diameter dimension itself of the short tubular resin molded body was as high as ± 0.1 mm, but in the comparative example product, the resin adhered to the inner surface of the short tubular resin molded body. The accuracy was as low as ± 1.5 mm.

Further, a hydrostatic pressure test was carried out on the above-mentioned example product and comparative example product in a state where pipes were inserted and connected to both receptacles. As a result, the comparative example product had a pipe joint and a pipe at a water pressure of 30 kgf / cm ^2. Although water leakage occurred from the gap, in the Example product, no water leakage was observed from such a portion, and in Examples 1 and ² , the short tubular resin molded body and the fiber-reinforced resin at a water pressure of 65 kgf / cm ² were observed. Water leakage occurred between the layers and, and in Example 3, the fiber-reinforced resin was broken.

[0042]

The present invention has the constitution as described above,
Considering that the occurrence of weeping in conventional fiber-reinforced resin pipe joints frequently occurs at the receiving part, a short tubular resin molded body that is a weeping prevention member is fixed only to the inner surface of the receiving port. As long as the bore diameters are the same, a common weeping prevention member can be used between different types of pipe joints such as a straight pipe joint, a bend pipe joint, a T-type pipe joint, and a cross type pipe joint. The number of molding dies can be reduced, and the management of the weeping prevention member becomes easy. In addition, a curable resin-impregnated fiber material that hardly causes resin dripping is wound around the boundary between the short tubular resin molded body and the core die, and then a fiber reinforced resin layer is formed by the FW method. It is possible to prevent the resin from dripping into the molded body, and to improve the inner surface dimensional accuracy of the short tubular resin molded body.
Inner peripheral smoothness can be guaranteed, and most of the fiber-reinforced resin can be formed by the FW method while maintaining good impregnation workability.

Therefore, according to the present invention, an FRP pipe joint having excellent weeping resistance, inner surface dimensional accuracy, and inner peripheral smoothness can be manufactured with good workability and at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a short tubular resin molded member used in the present invention.

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

FIG. 3 is an explanatory view showing a filament winding device used in the method for producing a fiber-reinforced resin pipe joint of the present invention.

FIG. 4 is an explanatory diagram showing a work procedure of an embodiment of a method for manufacturing a fiber-reinforced resin pipe joint according to the present invention.

FIG. 5 is an explanatory view showing a vacuum forming method of a short tubular resin molded member used in the present invention.

FIG. 6 is a sectional view showing another embodiment of the fiber-reinforced resin pipe joint according to the present invention.

FIG. 7 is a cross-sectional view of different types of fiber-reinforced resin pipe joints manufactured by the method for manufacturing a fiber-reinforced resin pipe joint according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Short tubular resin molded member 10 Short tubular resin molded body 21 Fiber reinforced resin portion facing the outer surface of the inner end of the short tubular resin molded body 22 Other fiber reinforced resin portion 210 Curable high viscosity resin impregnated fiber surface material 220 Cured Resin impregnated continuous fiber material 32 resin impregnation tank 34 feed eye 35 core type

Claims (2)

[Claims] 1. In a pipe joint made of fiber reinforced resin, a short tubular resin molded body is fixed to at least one inner surface of the receiving port from the receiving port inlet to the inner side, and the fiber reinforced facing the outer surface of the rear end of the molded body. A fiber-reinforced resin pipe joint, characterized in that the material of the resin portion is less likely to cause resin dripping in the uncured state than other fiber-reinforced resin portions. 2. A fiber in which at least one end of a rotary core mold is covered with a short tubular resin molded member, and a boundary portion between the outer surface of the inner end of the molded member and the outer surface of the core mold is impregnated with a high-viscosity curable resin. The face material is wound, then the curable resin-impregnated continuous fiber material is wound and laminated on the short tubular resin molded body and the core die, and further, the face resin impregnated resin and the continuous fiber material impregnated resin are heated. A method for producing a fiber-reinforced resin pipe joint, which comprises curing and then removing the cured body from the mold.