JPWO2009020054A1 - FRP reinforced vinyl chloride resin pipe joint and method for manufacturing the same - Google Patents

Abstract

An object of the present invention is to provide an FRP-reinforced PVC pipe joint in which reinforcing fibers and a thermosetting resin are uniformly dispersed, sufficiently filled and reinforced, have a good appearance and are not easily damaged, and a method for manufacturing the same. Bulk mold compound (BMC) or sheet molding compound (SMC) that forms an FRP layer is inserted into the lower mold using a mold consisting of an upper mold and a lower mold in which cavities are formed. After fixing the vinyl chloride resin pipe joint and inserting BMC or SMC into the upper part of the vinyl chloride resin pipe joint, the upper mold and the lower mold are closed and pressure integrated molding is performed.

Description

  The present invention mainly relates to FRP (fiber reinforced thermosetting resin) reinforced vinyl chloride resin pipe joints used for transport pipes for chemicals showing high temperature acids and alkalis, high temperature hot spring water, and the like, and a method for manufacturing the same. is there.

Conventionally, FRP reinforced vinyl chloride resin pipe joints (hereinafter referred to as FRP reinforced PVC pipe joints) used for transport pipes for the above chemicals having high temperature corrosivity and high temperature hot spring water, etc. (Hand pile molding method) is adopted, but the hand lay-up method is performed manually, so it is inefficient, requires skill, and has a lot of wasted materials that are discarded after production. It ’s bad. In addition, it is difficult to obtain a homogeneous molded product, and the appearance is poor and the outer diameter is not constant. As a method for solving these problems, there is a method of manufacturing a flanged pipe joint made of FRP reinforced thermoplastic resin (refer to JP-A-5-185536). When manufacturing a synthetic resin flanged pipe joint reinforced with an FRP layer made of fiber reinforced thermosetting resin, the structure has an inner surface shape corresponding to the outer surface shape of the flanged pipe joint material. A mold capable of ensuring a constant resin thickness between the outer surface of the joint material at the time of setting was prepared, and a fiber reinforced thermosetting resin was first laminated on the outer surface of the pipe joint material by a hand lay-up method. Next, the pipe joint material is set in a mold, and the fiber-reinforced thermosetting resin is cured while being uniformly pressurized as a whole. After the resin is completely cured, the mold is removed and finished. Since this method can evenly adhere a fiber reinforced thermosetting resin layer (hereinafter referred to as FRP layer) even to a portion of the pipe joint material where the resin is difficult to spread such as the flange outer surface and the flange base, It is possible to obtain a product having a good appearance in which the shape of each part of the flange is uniform and free of bubbles in the interface between the FRP and the flange or in the FRP.
As another method for manufacturing FRP-reinforced PVC pipe joints such as sockets and elbows, there is a method for manufacturing a reinforced resin pipe joint by a filament winding method (see Japanese Patent Application Laid-Open No. 4-45918). Its structure is that the inner layer of the central part having the branch deformation part of the pipe joint is molded in advance with a resin or reinforced resin to form a molded body, and after the core mold for molding the shape of the receiving portion is attached to the molded body, the core mold In addition, a reinforced resin molding material is supplied to the outer periphery of the molded body by the filament winding method to mold and cure the pipe joint, and then the core mold is removed, so that the joint can be homogenized and strong against internal pressure. The dimensional accuracy of the receiving part is also good.

However, the manufacturing method of the conventional FRP reinforced synthetic resin flanged pipe joint is a process in which a mold that is first set on a pipe joint material by a hand lay-up method is formed by laminating FRP (fiber reinforced thermosetting resin). Therefore, there is a problem that it takes time and labor to manufacture the pipe joint. Also, in pipe fittings other than flange-shaped ones, the effectiveness is low, and when this manufacturing method is used for sockets, especially cylindrical pipe fittings with bent flow paths such as elbows and cheeses There is a problem that a malfunction occurs. If this manufacturing method is used for an elbow-shaped pipe joint, a split mold set from both sides of the elbow, which is a pipe joint material, is created by laminating FRP, and two pipe joint materials are prepared. It is manufactured while pressing with the mold sandwiched. However, since two molds must be made by laminating FRP, the mold manufacturing process is doubled, and it takes time and labor to manufacture the pipe joint. In addition, since the strength of the weld line portion that becomes the mating surface of the two molds is inferior to that of the other portions, the weld line is formed at the bent portion of the joint where stress is likely to concentrate. There was a problem that it was easy. A conceivable method is to devise the shape of the mold so that a weld line cannot be formed at the bent portion of the joint. However, since the shape of the mold becomes complicated, molding becomes difficult.
In addition, the method of manufacturing the reinforced resin pipe joint can cope with shapes such as elbows and cheeses, but since the core material is manufactured by winding glass fiber impregnated with resin, a manufacturing facility for performing winding is newly provided. There is a problem that it is necessary to provide a large amount of manufacturing equipment and a large installation space for the manufacturing equipment. In addition, the number of winding processes increases and it takes time to manufacture one pipe joint (especially the winding process), and the dimensional accuracy of the receiving part is good, but the outer diameter is not constant, so pipe construction There is a problem that it becomes difficult to attach the support to the pipe joint part.
In view of the above problems, the present invention is mainly applied to a vinyl chloride resin pipe joint reinforced with an FRP layer, in which reinforcing fibers and thermosetting resin are uniformly dispersed and sufficiently filled and reinforced. An object is to provide an elbow or cheese-shaped FRP-reinforced PVC pipe joint and a method for producing the same.

As a result of various investigations to solve the above-described problems of the prior art, the present inventors use a bulk molding compound (hereinafter abbreviated as BMC) or a sheet molding compound (hereinafter abbreviated as SMC) for the FRP layer. Thus, the inventors have found that the above object can be achieved and achieved the present invention.
That is, the present invention relates to a method for manufacturing a FRP-reinforced vinyl chloride resin pipe joint reinforced with a fiber FRP layer using a mold composed of an upper mold and a lower mold in which a cavity is formed. The BMC or SMC forming the FRP layer is inserted, the vinyl chloride resin pipe joint molded in advance in the lower mold is fixed, and the BMC or SMC is placed on top of the vinyl chloride resin pipe joint. After the insertion, the first feature is that the upper mold is closed and integrally molded under pressure.
A second feature is that the mold is provided with a slide core driven by a hydraulic cylinder, and the slide core is inserted and fixed in each opening of the vinyl chloride resin pipe joint. To do.
The slide core is provided with a contact surface that contacts the end surface of the opening of the FRP-reinforced vinyl chloride pipe joint, and the contact surface is 0. 0 mm from the position of the end surface of the opening of the FRP-reinforced vinyl chloride pipe joint. The third feature is that it protrudes by 3 to 0.8 mm.
The upper mold and the lower mold are closed stepwise, and the upper mold and the lower mold are temporarily stopped in a state where the upper mold and the lower mold are closed from the opening degree of 100% to the opening degree of 15 to 25%. The fourth feature is that the valve is temporarily stopped in a state in which the opening degree is closed to 3 to 8%, and then is fully closed in an opening degree of 0%.
A fifth feature is that at least a part of the contact surface of the upper mold and / or the lower mold of the mold is formed at an acute angle with the peripheral edge of the cavity as a tip.
Furthermore, a sixth feature is that the FRP-reinforced vinyl chloride resin pipe joint manufactured by the method for manufacturing these FRP reinforced vinyl chloride resin pipe joints is used.

The present invention has the above-described configuration, and the following excellent effects can be obtained by using this.
(1) An FRP reinforced PVC pipe is formed by forming an FRP layer easily and without increasing the number of manufacturing steps for cylindrical vinyl chloride resin pipe joints (hereinafter referred to as PVC pipe joints) such as elbows and cheeses. A joint can be manufactured, and there is no waste of material, and it can be manufactured with little waste.
(2) FRP reinforced PVC pipe fittings that can provide uniform reinforcing fibers over the entire circumference even with a complicated pipe joint configuration, have stable physical properties and appearance, and have a constant outer diameter. Is obtained.
(3) Since the FRP layer having a uniform thickness can be formed and the weld line portion has strength, a joint that maintains high water pressure strength and is not easily damaged can be obtained.
(4) Even when the dimensions of the PVC pipe joint to be fixed are deviated, by inserting the heated slide core and integrally forming with pressure, it is possible to reduce the taper of the receiving port or the angle of the joint at the time of molding. The dimensions can be corrected, and an FRP-reinforced PVC pipe joint with good dimensional accuracy can be obtained.
(5) Even if burrs are generated, the burrs can be cut in the mold and the FRP-reinforced PVC pipe joint can be taken out.
(6) Since the upper mold and the lower mold are closed stepwise, reliable air bleeding can be performed, so that voids and molding unevenness can be prevented from remaining in the mold.

FIG. 1 is a longitudinal sectional view showing a mold when BMC is inserted into the lower mold.
FIG. 2 is a longitudinal sectional view showing a mold when the PVC pipe joint is installed from FIG. 1 and BMC is inserted into the upper part of the PVC pipe joint.
FIG. 3 is a longitudinal sectional view showing a mold when the upper mold is closed from FIG.
FIG. 4 is a longitudinal sectional view showing an FRP-reinforced PVC pipe joint.

Hereinafter, although an embodiment of the present invention is described with reference to drawings, it cannot be overemphasized that the present invention is not limited to this embodiment. FIG. 1 is a longitudinal sectional view showing a mold when BMC is inserted into the lower mold. FIG. 2 is a longitudinal sectional view showing a mold when the PVC pipe joint is installed from FIG. 1 and BMC is inserted into the upper part of the PVC pipe joint. FIG. 3 is a longitudinal sectional view showing a mold when the upper mold is closed from FIG. FIG. 4 is a longitudinal sectional view showing an FRP-reinforced PVC pipe joint.
In the figure, reference numeral 1 denotes a lower mold of a mold, in which a cavity 3 of an FRP-reinforced PVC elbow 2 is formed. On the two sides of the lower mold 1 (both opening sides of the PVC elbow 8), hydraulic cylinders 4 are respectively installed on substantially the same axis as the opening, and the cylinder 4 has an opening in the PVC elbow 8 to be described later. A slide core 5 to be inserted and fitted is provided. In addition, a protrusion pin (not shown) for taking out the FRP-reinforced PVC elbow 2 is provided at the lower part of the lower mold 1.
By inserting the slide core into each opening of the PVC elbow 8, the operation of fixing the PVC elbow 8 to the mold is simplified, and the PVC elbow 8 is fixed so that it does not move. Can be prevented from being deformed. Here, the outer peripheral dimension of the slide core 5 is formed by the inner peripheral dimension of the PVC elbow 8 and a clearance of 0.1 to 0.3 mm. Even if the PVC elbow 8 is softened and deformed at the time of pressure integral molding, The dimension set by the slide core 5 can be corrected. At this time, even if the PVC elbow 8 to be fixed is displaced due to internal stress at the time of injection molding, the heated slide core is inserted into the opening of the PVC elbow 8 and is integrally molded by pressure. It is possible to correct the dimensions such as the taper of the receiving port and the shift of the joint angle at the time of molding, and to obtain the FRP-reinforced PVC elbow 2 with good dimensional accuracy. Further, the slide core 5 is formed with a contact surface 12 with which the opening end surface of the FRP-reinforced PVC elbow 2 made of the PVC elbow 8 and the FRP layer 10 contacts, and when the slide core 5 is inserted into the PVC elbow 8, The contact surface 12 protrudes about 0.3 to 1.0 mm from the position of the end surface of the PVC elbow 8. Thereby, the contact surface 12 presses the opening end surface of the FRP-reinforced PVC elbow 2 composed of the PVC elbow 8 and the FRP layer 10 at the time of pressure integral molding, and the end surface is sealed, and the end surface of the PVC elbow 8 The BMC 9 is prevented from leaking into the inner periphery. Here, the protruding amount of the contact surface 12 needs to be 0.3 mm or more in order to press the end surface of the PVC elbow 8, and the force applied to the end surface of the PVC elbow 8 becomes large and a load is applied to the PVC elbow 8. It is necessary to be 1.0 mm or less so as not to be applied.
Further, the working pressure of the cylinder 4 is preferably equal to or higher than the internal pressure applied to the cavity 3 at the time of pressure integral molding. Furthermore, it is preferable to provide a stopper portion (not shown) that can be engaged with the slide core 5 or the cylinder 4 in the upper mold 6 and / or the lower mold 1 when the upper mold 6 and the lower mold 1 are closed. For example, the upper die 6 is provided with a convex stopper portion, the slide core 5 is provided with a concave fitting portion that can be fitted with the stopper portion, and the upper die 6 and the lower die 1 are closed when the upper die 6 and the lower die 1 are closed. By forming the joint portion so as to be fitted, it is possible to prevent the slide core 5 from moving due to the internal pressure applied to the cavity 3 during pressure integral molding, and to obtain the FRP-reinforced PVC elbow 2 with good dimensional accuracy. it can. In addition, it is preferable to provide a stopper portion because good molding can be performed even if the operating pressure of the cylinder is lower than the internal pressure in the cavity 3 at the time of pressure integral molding.
Reference numeral 6 denotes an upper mold of the mold, in which a cavity 3 of an FRP-reinforced PVC elbow 2 is formed. Of the contact surface of the upper mold 6 that contacts the lower mold 1, the peripheral edge 7 of the cavity 3 is formed to have an acute angle with the peripheral edge 7 of the cavity 3 as the tip. The angle θ of the peripheral edge 7 at this time is provided to be 45 ° with respect to the contact surface with the lower mold 1.
Reference numeral 8 denotes a PVC elbow which is a PVC pipe joint previously formed by injection molding and installed in a mold. In this embodiment, the PVC pipe joint is an elbow, but elbows, bends, cheeses, and sockets are particularly suitable, and flanges, caps, and the like may be used.
Reference numeral 9 denotes a BMC inserted into the lower mold 1 and the upper mold 6, and the FRP layer 10 is formed in the FRP-reinforced PVC elbow 2 when the PVC elbow 8 is FRP reinforced.
The material of the pre-formed PVC pipe joint used in the present invention is not particularly limited, but generally used rigid vinyl chloride resin, chlorinated vinyl chloride resin, ethylene-vinyl chloride copolymer resin, or vinyl acetate- A vinyl chloride copolymer resin and the like are preferable.
BMC is also called a premix, and is a molding material that is kneaded into a clay by adding a filler or the like as required in addition to resin and reinforcing fibers. On the other hand, SMC refers to a sheet-like molding material in which a reinforcing fiber mat is impregnated with a resin. All of them are molding materials having a characteristic that there is not much restriction on the structure of the mold because the resin is not used in a liquid state, although an appropriate amount is inserted into the mold and heated and pressurized. In particular, BMC is suitable because it is easy to distribute the material necessary for one molding, can be molded without waste of material and with little waste, and can be easily molded in a shape that matches the cavity during molding.
Examples of the thermosetting resin used in the BMC or SMC of the present invention include unsaturated polyester resins, vinyl ester resins, epoxy resins, and phenol resins. Among them, unsaturated polyester resins are preferred in various aspects. As mentioned. When the unsaturated polyester resin is a bisphenol-based unsaturated polyester resin, it takes a certain amount of time to cure when a FRP layer is formed on the PVC joint, so that the joint has a bent flow path such as an elbow. It is suitable because it can form a homogeneous FRP layer, and is a polyhydric alcohol component containing at least a part of a polyhydric alcohol component of an unsaturated polyester resin. A liquid resin obtained by dissolving an unsaturated polyester resin obtained by reacting in a styrene monomer and adding a polymerization inhibitor, a polymerization catalyst or the like is preferable. In addition, when the unsaturated polyester resin is a matrix liquid resin comprising a liquid resin containing a high molecular weight bisphenol unsaturated polyester resin and a liquid resin containing a low molecular weight bisphenol unsaturated polyester resin, the alkali resistance of the FRP-reinforced PVC pipe joint is improved. Therefore, it is preferable. Moreover, BMC or SMC is comprised by adding a hardening | curing agent, a thickener, a filler, a coloring agent, etc. as needed other than the above-mentioned reinforcing fiber and thermosetting resin.
Moreover, it is preferable that the thermosetting resin used for BMC or SMC mix | blends 50-150 weight part of reinforcement fibers with respect to 100 weight part of unsaturated polyester resin. This is required to be 50 parts by weight or more in order to obtain the strength of the reinforcing resin composition, and is within the range where kneading is easily performed at the time of producing the composition, and fibers appear on the surface after molding, resulting in poor appearance. It is necessary to be 150 parts by weight or less so as not to become. The reinforcing fiber used for the BMC or SMC forming the FRP layer is preferably a glass fiber, and a polyvinyl alcohol fiber, an aromatic polyamide fiber, a carbon fiber, or the like is preferable. Moreover, the shape is mentioned as a suitable thing for the chopped strand cut | disconnected by 3-25 mm.
Moreover, it is preferable that an inorganic filler mix | blends 0.2 weight part-10 weight part with respect to 100 weight part of unsaturated polyester resin. This needs to be 0.2 parts by weight or more in order to improve the thermal conductivity of the composition, and in order to improve the storage stability of the composition and not to reduce the impact resistance, it is 10 parts by weight or less. There must be. Examples of the inorganic filler in the present invention include calcium carbonate, mica, barium sulfate, calcium sulfate, clay, perlite, shirasu balloon, diatomaceous earth, calcined alumina, calcium silicate, talc, and the like. Of these, silica and calcium carbonate are particularly suitable.
Moreover, it is preferable to mix | blend 0.5-4 weight part with a hardening | curing agent with respect to 100 weight part of unsaturated polyester resin. In order to cure the resin composition under suitable molding conditions, it is necessary to be 0.5 parts by weight or more, and it is necessary to be 4 parts by weight or less so that the resin is hardened too quickly and molding becomes difficult. Further, a curing agent for low temperature is desirable, and bis (4-tertiarybutylcyclohexyl) peroxydicarbonate (Percadox 16), tertiary amyl peroxy 2-ethylhexanoate (trigonox), benzoyl peroxide (Cadox) etc. are mentioned as a suitable thing.
Moreover, you may comprise by adding a mold release agent, a thickener, a coloring agent, a hardening accelerator, etc. to 100 weight part of unsaturated polyester resins as needed. About each additive, what is necessary is just to mix | blend to such an extent that the hardening of an additive can be exhibited, 0-2 weight part of mold release agents, 0-5 weight part of thickeners, 0-15 weight part of coloring agents, hardening accelerator 0 It is preferable to blend ~ 1 part by weight.
In addition, when the production method of BMC is given, after kneading a mixture of a thermosetting resin, a release agent, a colorant, a curing agent and the like with a filler, and then mixing a thickener, Disperse the reinforcing fibers uniformly. The mixture is taken out from the kneader, formed into a predetermined size and shape, and aged to form BMC. In addition, SMC production methods include applying a compound in which a thickening agent is mixed with a mixture in which a thermosetting resin, a filler, a release agent, a colorant, a curing agent and the like are uniformly kneaded and dispersed on a polyethylene film. Then, a predetermined reinforcing fiber is pressure-impregnated and formed into a sheet, and then rolled, and aged at room temperature or under heating to obtain SMC.
Here, the temperature of the mold composed of the upper mold 6 and the lower mold 1 needs to be set to 40 to 120 ° C, more preferably 60 to 100 ° C. This is because the mold temperature is preferably 40 ° C. or higher in order to increase the molding efficiency without lengthening the time for the BMC 9 to cure, and the mold temperature is 120 ° C. or lower because the PVC elbow 8 is not deformed such as swelling. good. Thereby, it is suitable that the curing temperature of BMC9 is 40-120 degreeC, More preferably, it is 60-100 degreeC. In order to improve productivity without prolonging the molding time, the curing temperature is preferably 40 ° C. or higher, and the curing temperature is preferably 120 ° C. or lower in order to suppress deterioration of the material so that the BMC 9 can be used for a long period of time. Here, the curing temperature is the temperature at which the molding time required to obtain a plate-shaped molded product of 100 × 100 × 10 mm using BMC9 or SMC with a mold at that temperature is 5 to 20 minutes. It is. For example, BMC 9 having a curing temperature of 80 ° C. is BMC 9 having a molding time of 5 to 20 minutes required for obtaining a molded product with an 80 ° C. mold.
Accordingly, the curing agent used for BMC 9 needs to react at a lower temperature than the curing agent generally used. For example, as a curing agent for BMC 9 having a curing temperature of 70 ° C. using an unsaturated polyester resin, a peroxide having a 10-hour half-life temperature of about 40 to 50 ° C. is preferably used. Further, at the time of manufacturing the BMC 9 in this case, the temperature of the raw material mixture needs to be kept at a low temperature at which the mixture is not cured, and the aging needs to be performed at a low temperature as well. For example, as a method for producing BMC 9 having a curing temperature of 80 ° C. using an unsaturated polyester resin, an unsaturated polyester resin, a filler, a release agent, a thickener, a curing agent, etc. are premixed at 20 ° C., A method of obtaining BMC 9 by mixing the reinforcing fiber and this premix with a Hensell mixer to obtain a mixture, sealing the mixture and aging at 20 ° C. for 1 day is employed.
In the mold of the present invention, it is preferable that at least a part of the contact surface of the upper mold and / or the lower mold is formed at an acute angle with the peripheral edge 7 of the cavity as a tip. The angle θ of the peripheral edge portion 7 is desirably provided at 30 to 60 °, more preferably 30 to 45 °. 30 ° or more is good for obtaining the sharp edge strength of the peripheral edge portion 7, and 60 ° or less is good for cutting the BMC protruding from the cavity 3 with a mold.
Next, the manufacturing method of a FRP reinforced PVC pipe joint is demonstrated.
First, BMC 9 is inserted into the lower mold 1 heated to 80 ° C. (state shown in FIG. 1). Next, a PVC elbow 8 preliminarily coated with a primer is placed on the BMC 9 in which the lower mold 1 is inserted, and the slide core 5 is inserted into each opening of the PVC elbow 8 to insert the PVC elbow 8. To fix. Next, the BMC 9 is inserted into the upper portion of the PVC elbow 8 (state shown in FIG. 2). At this time, the insertion amount of the BMC 9 is 25 to 40% of the cavity volume in the lower mold 1 and 60 to 80% of the cavity volume is inserted in the upper part of the PVC elbow 8. Further, the BMC 9 to be inserted into the upper part of the PVC elbow 8 is inserted so that the bent part (the position of the cavity 3 corresponding to the bent part 11 in FIG. 4) becomes larger.
Next, the upper mold 6 and the lower mold 1 heated to 80 ° C. are closed stepwise. Assuming that the opening degree of the upper mold 6 and the lower mold 1 when the BMC 9 is inserted is 100%, the first stage is temporarily stopped in a state where the opening degree is closed to 15 to 25% and held for about 1 minute. At this time, the convex portion 13 of the upper mold 6 and the concave portion 14 of the lower mold 1 are fitted to about a half, and the BMC 9 is heated in the mold and the air is released from the mold. As a second step, the valve is temporarily stopped with the opening degree closed to 3 to 8% and held for about 1 minute. At this time, the upper mold 6 and the lower mold 1 are in a state where there is a slight gap, and the BMC 9 is pressed and deformed so as to reach the inside of the cavity 3 and the air is released. As a third stage, pressure integral molding is performed in a fully closed state with an opening degree of 0%. After the pressure integrated molding and holding for a certain period of time, the FRP layer 10 is provided on the PVC elbow 8 to form the FRP-reinforced PVC elbow 2 (the state shown in FIG. 3), the upper die 6 is opened, and the slide core 5 is removed. Thereafter, the FRP-reinforced PVC elbow 2 is pushed out with an ejector pin.
According to the above manufacturing method, the upper mold 6 and the lower mold 1 can be closed in stages, so that reliable air bleeding can be performed, and voids and molding unevenness are generated by the air remaining in the mold. The BMC 9 can be efficiently heated. In this embodiment, BMC 9 having 25 to 40% of the cavity volume and 60 to 80% of the cavity volume is inserted in the upper part of the PVC elbow 8 in the lower mold 1. The reason is that when the same amount of BMC 9 is inserted into the upper part of the lower mold 1 and the PVC elbow 8, the BMC 9 on the lower mold 1 side is pushed upward and filled into the cavity 3 at the time of pressure integral molding. Rather than letting the amount of BMC 9 inserted into the upper part of the PVC elbow 8 increase, the BMC 9 on the PVC elbow 8 side is pushed downward and filled into the cavity 3 at the time of pressure integral molding. This is preferable because it can be distributed more efficiently. If the pipe joint has a bent part of the flow path such as elbow, bend, cheese, etc., if the BMC 9 is inserted in the bent part of the cavity 3 so that there is a large amount, stress will occur if fluid pressure is applied when using the FRP-reinforced PVC elbow 2 This is preferable because strong strength is obtained at the bent portion 11 of the PVC elbow 8 where the concentration of the PVC elbow 8 is difficult to break.
Here, the total amount of insertion of BMC 9 is desirably in the range of 105 to 115% with respect to the cavity volume. The reason why it may exceed 100% is that the BMC 9 is more strongly pressed in the mold by inserting it slightly more than the cavity volume, and the dense FRP layer 10 is uniformly passed over the entire circumference of the joint. This is because it is formed without a shortage. Moreover, although excess BMC 9 may leak from the mold as burrs, the burrs that have leaked from the mold are due to the tip of the peripheral edge portion 7 of the cavity on the contact surface of the mold being provided at an acute angle. The burr can be cut at the tip of the sharp peripheral edge 7, and the FRP-reinforced PVC elbow 2 can be taken out while the generated burr is cut in the mold. Thereby, the effort which removes a burr | flash can be saved and it can shape | mold in a shorter time. In addition, the manufacturing method of the present invention can be performed using BMC, whereby the material necessary for one molding can be easily and accurately distributed among the methods for manufacturing the FRP-reinforced PVC elbow. For this reason, it is possible to form an FRP-reinforced PVC elbow having a stable outer diameter, and it is possible to perform molding with less waste because there is no waste of material during molding.
The FRP-reinforced PVC elbow 2 obtained by the above manufacturing method has an FRP layer with a uniform thickness, and the strength of the weld line portion is equal to that of the other portions, and stress concentration Since the easily bent portion 11 is not easily damaged, it has high water pressure strength. In addition, by inserting and inserting a heated slide core and press-molding integrally, it is possible to correct the dimensions such as the taper of the receiving port and the deviation of the angle of the pipe joint and obtain an FRP-reinforced PVC elbow with good dimensional accuracy it can. Furthermore, it has a good external appearance by pressure integral molding, and an accurate outer diameter dimension can be obtained. For this reason, it is preferable that the support is easily attached when the pipe is constructed.
In the production method of the present invention, a primer layer (not shown) may be formed between the PVC elbow 8 and the FRP layer 10, and a primer is applied to the outer periphery of the PVC elbow 8 in advance. 10 may be formed. By forming a primer layer (not shown), the PVC elbow 8 and the FRP layer 10 are firmly bonded, and a gap is not generated between the PVC elbow 8 and the FRP layer 10 to be surely reinforced. Can do. Further, when an internal water pressure is applied to the FRP reinforced PVC elbow 2, if a crack occurs in the FRP layer 10, the crack can be prevented from propagating to the PVC elbow 8. Strength can be improved.
Next, the FRP-reinforced PVC elbow of the present invention was molded and its performance was evaluated by the test method shown below.
(1) Water pressure strength test After filling both openings of the FRP-reinforced PVC elbow with water filled, the liquid temperature was raised and the internal liquid temperature was maintained at 90 ° C for 2 hours, and then gradually The water pressure was increased and the water pressure when the FRP-reinforced PVC elbow was damaged was measured.
The BMC used for the test was manufactured by the following method.
100 parts by weight of bisphenol unsaturated polyester resin, 95 parts by weight of glass chopped strands cut to 13 mm as reinforcing fibers, 1 part by weight of silica powder as inorganic filler, 2.5 parts by weight of curing agent, and 8 parts of colorant 1 part by weight, 2 parts by weight of zinc stearate, and 2 parts by weight of magnesium oxide. First, an unsaturated polyester resin, a colorant, and a curing agent are added, and the mixture is stirred and mixed for about 1 minute. Add ingredients and stir and mix for about 3 minutes. Next, glass chopped strands are added and mixed with stirring for about 10 minutes. And BMC was obtained by ageing | curing the obtained mixture.

表１より、作業性においては、実施例１は作業が簡単で特に困難な作業がなく手間が掛からずに作業性が良好であったのに対し、比較例１ではハンドレイアップでＰＶＣエルボ全体にＦＲＰ層を設けるので作業が困難で手間が掛かるので作業性は悪かった。また、比較例１では成形中に廃棄物が多く出るため材料の無駄が多かったのに対し、実施例１ではバリが少し出た以外は廃棄されるものは無く、廃棄物は少なくて済んだ。また、外観においては、実施例１はＦＲＰ層が均一な肉厚で形成されて外径寸法が安定しており、表面がなめらかで光沢があり外観が良好であるのに対し、比較例１ではＦＲＰ層の肉厚にばらつきがあり、外径寸法も安定しておらず、表面にざらつきがあり光沢がなく外観は悪かった。また、耐水圧強度においては、強度自体は共に継手として使用するのに必要な強度を有しており、あまり大きな差はないが、肉厚が均一でありＦＲＰ層の密度が高く形成された実施例１の方が比較例１より耐圧強度は若干高くなり、より高い水圧に対して使用が可能である。The FRP layer 10 was formed on the PVC elbow 8 having a nominal diameter of 100 mm by the procedure of this embodiment, and the FRP-reinforced PVC elbow 2 was obtained. The workability at the time of molding, the appearance of the FRP-reinforced PVC elbow after molding, and the water pressure resistance were evaluated. The test results are shown in Table 1.
<Comparative Example 1>
Using an unsaturated polyester resin as a thermosetting resin, a glass chopped strand mat and a glass roving cloth as a reinforcing fiber, and laminated on a PVC elbow having a nominal diameter of 100 mm by a hand lay-up method, an FRP-reinforced PVC elbow was obtained. . The thickness of the FRP layer was set to be the same as in Example 1. The workability at the time of molding, the appearance of the FRP-reinforced PVC elbow 2 after molding, and the water pressure resistance were evaluated. The test results are shown in Table 1.

As shown in Table 1, in terms of workability, Example 1 was simple, and there was no particularly difficult work, and the workability was good with no effort, whereas in Comparative Example 1, the entire PVC elbow was obtained by hand lay-up. Since the FRP layer is provided on the work, the work is difficult and time-consuming, so the workability is poor. Further, in Comparative Example 1, a large amount of waste was generated during molding, so that a lot of material was wasted. In Example 1, there was no waste except for a small amount of burrs, and there was little waste. . In addition, in Example 1, the FRP layer was formed with a uniform thickness and the outer diameter was stable, the surface was smooth and glossy, and the appearance was good. The thickness of the FRP layer varied, the outer diameter was not stable, the surface was rough, the surface was not glossy, and the appearance was poor. In addition, in terms of the water pressure resistance, both strengths have the strength necessary for use as a joint and there is not much difference, but the thickness is uniform and the density of the FRP layer is high. Example 1 has a slightly higher pressure resistance than Comparative Example 1, and can be used for higher water pressures.

Claims (6)

A method of manufacturing a FRP-reinforced vinyl chloride resin pipe joint reinforced with a fiber reinforced thermosetting resin (FRP) layer using a mold composed of an upper mold and a lower mold in which a cavity is formed,
Insert the bulk molding compound (BMC) or sheet molding compound (SMC) that forms the FRP layer into the lower mold,
Fix the pre-formed vinyl chloride resin pipe joint to the lower mold,
After inserting the BMC or the SMC on top of the vinyl chloride resin pipe joint,
The upper mold and the lower mold are closed and formed by pressure integral molding.
A method for producing an FRP-reinforced vinyl chloride resin pipe joint, characterized in that: 2. A slide core driven by a hydraulic cylinder is provided in the mold, and the slide core is inserted and fixed in each opening of the vinyl chloride resin pipe joint. The manufacturing method of the FRP reinforced vinyl chloride resin pipe joint as described. The slide core is provided with a contact surface that contacts the end surface of the opening of the FRP-reinforced vinyl chloride pipe joint, and the contact surface is 0. 0 mm from the position of the end surface of the opening of the FRP-reinforced vinyl chloride pipe joint. The method for producing an FRP-reinforced vinyl chloride resin pipe joint according to claim 2, wherein the pipe joint protrudes by 3 to 0.8 mm. The upper mold and the lower mold are closed in stages,
From the opening degree 100% when the upper mold and the lower mold are fully opened,
Stop once with the opening degree 15-25% closed,
After that, stop once with the opening degree 3-8% closed,
4. The method for manufacturing an FRP-reinforced vinyl chloride resin pipe joint according to claim 1, wherein the fully closed state with an opening degree of 0% is thereafter set. 5. The at least part of the contact surface of the upper mold and / or the lower mold of the mold is formed at an acute angle with the peripheral edge of the cavity as a tip. A method for producing the FRP-reinforced vinyl chloride resin pipe joint according to claim 1. An FRP-reinforced vinyl chloride resin pipe joint manufactured by the method for manufacturing an FRP-reinforced vinyl chloride resin pipe joint according to any one of claims 1 to 5.

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