JPH0622913B2 - FRP reinforced vinyl chloride resin pipe joint and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is mainly reinforced with FRP (fiber reinforced thermosetting resin) used for transportation pipes of chemicals showing high temperature acid or alkali, hot spring water, etc. The present invention relates to a vinyl chloride resin pipe joint and a method for manufacturing the pipe joint.

[Conventional technology]

Conventionally, FRP reinforced vinyl chloride resin pipe fittings (hereinafter abbreviated as FRP reinforced PVC pipe fittings) used for transportation piping of the above-mentioned chemicals having high temperature corrosiveness and high temperature hot spring water are well known. There is. A hand lay-up method (hand-roll forming method) is usually adopted as a method for manufacturing the pipe joint, but the hand-lay-up method is a manual work, so that the efficiency is poor.
In addition, it requires skill and productivity is very poor. Moreover, there are problems that it is difficult to obtain a homogeneous molded product and the appearance is poor.

As a method for solving these problems, recently, a resin injection method (hereinafter abbreviated as RI method) has been in the limelight. -14920 publication. The molding method disclosed in the publication is
After inserting the glass fiber wound prototype into a vinyl chloride resin flanged socket into the cavity of the mold divided into upper and lower molds, inject thermosetting resin from the gate part The thermosetting resin is pressed into the gap between the mold and the original shape, and the thermosetting resin is impregnated into the original glass fiber.
It cures.

[Problems to be Solved by the Invention]

However, the FR by the RI method represented by the above method
In forming a P-reinforced PVC pipe joint, the following problems are likely to occur.

1) It is difficult to uniformly wind a reinforcing fiber such as glass fiber around a vinyl chloride resin pipe fitting (hereinafter abbreviated as PVC fitting). In particular, it is difficult to maintain the fiber layer to have a uniform thickness in a portion such as a rib where a complicated shape is added, a curved portion, or a corner portion.

2) Similarly, even when setting the original shape of the pipe joint on which the reinforcing fibers are wound in the resin mold, it is difficult to set the original shape so that the resin mold spaces are uniform due to the deformation of the reinforcing fibers. is there.

3) Because of the reasons 1) and 2) above, the reinforcing fibers are not evenly wound, so that the thermosetting resin to be molded is not evenly inserted. In particular, in the high density portion of the reinforcing fiber, the penetration of the thermosetting resin is poor, and there is also a portion where the thermosetting resin is not filled.

4) Since the thermosetting resin to be molded has a relatively low viscosity, the enclosed air cannot be pushed out of the mold, and voids are likely to occur.

5) In addition to the reason of 3) above, for example, the glass fiber portion where the thermosetting resin has not penetrated looks white and mottled,
Further, the reason of the above 4) is also taken into consideration, and it is difficult to obtain a good appearance.

The present invention has been made in view of the problems of the prior art as described above, and an object thereof is an FRP reinforced PVC having a good appearance in which reinforcing fibers and a thermosetting resin are uniformly dispersed and sufficiently filled and reinforced. A pipe joint and a method for manufacturing the pipe joint.

[Means for Solving the Problems]

As a result of various studies to solve the above-mentioned 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 reinforcing layer. As a result, the inventors have found that the above objects can be achieved, and completed the present invention.

That is, the present invention relates to a PVC resin pipe joint reinforced with an FRP layer, wherein the FRP layer is formed by using BMC or SMC, and a FRP reinforced PVC resin pipe joint is preformed. In the method for producing a FRP reinforced PVC resin joint, the PVC resin pipe joint is reinforced and integrated with an FRP layer using BMC or SMC.

The present invention will be described in detail below.

The material of the PVC pipe joint used in the present invention is a commonly used hard vinyl chloride resin, chlorinated vinyl chloride resin, ethylene-vinyl chloride copolymer resin, vinyl acetate-vinyl chloride copolymer resin, or the like. It can be mentioned as a suitable one. Further, as the type of the pipe joint, a flange, a socket, a cheese, an elbow, a bend, a cap and the like can be cited as a preferable example.

BMC is also called a premix, and is a molding material that is kneaded into a putty by adding a filler and the like as necessary in addition to the resin and the reinforcing fiber and kneading. On the other hand, SMC refers to a molding material obtained by gelling a reinforcing fiber mat after impregnating it with a resin. All of them are molding materials having a characteristic that the resin is not used in a liquid state as it is, although a proper amount is inserted into the mold and the mold is heated and pressed, so that there is not much restriction on the structure of the mold.

Suitable reinforcing fibers used for BMC or SMC forming the FRP reinforcing layer are generally used glass fibers, polyvinyl alcohol fibers, aromatic polyamide fibers, carbon fibers and the like. Further, the shape thereof is preferably chopped strands cut into 3 to 25 mm.

Examples of the thermosetting resin used for BMC or SMC include unsaturated polyester resin, vinyl ester resin, epoxy resin, and phenol resin. Among them, unsaturated polyester resin is preferable in various aspects. . The unsaturated polyester resin may be any liquid resin in which an ester compound of a polyhydric alcohol, an unsaturated polybasic acid and a saturated polybasic acid is dissolved in a monomer such as styrene capable of copolymerizing with an unsaturated bond. But it's okay.

Further, BMC or SMC is configured by adding a curing agent, a thickener, a filler, a colorant and the like, if necessary, in addition to the above-mentioned reinforcing fiber and thermosetting resin.

BMC or SMC can be obtained by blending the above-mentioned respective raw materials, and a suitable example of blending the composition is as follows.

Unsaturated polyester resin 100 parts by weight Glass fiber (chopped 15 to 120 parts by weight strand 6 mm) Filler (heavy calcium carbonate) 0 to 150 parts by weight Release agent (zinc stearate) 0 to 2 parts by weight Thickener (MgO ) 0.5 to 5 parts by weight Curing agent 1 to 4 parts by weight Coloring agent 0 to 10 parts by weight Curing accelerator 0 to 1 parts by weight As a manufacturing method of BMC or SMC, a generally adopted method can be preferably applied. For example, as a method for producing BMC, a mixture of a thermosetting resin, a release agent, a coloring agent, a curing agent, and the like, and a filler are kneaded with a kneader, and then a thickener is mixed. Disperse the reinforcing fibers evenly.
The mixture is taken out of the kneader, shaped into a predetermined size, and aged to obtain BMC. In addition, as a method for producing SMC, a compound in which a thickener is mixed with a mixture in which a thermosetting resin, a filler, a release agent, a colorant, and a curing agent are uniformly kneaded and dispersed is applied onto a polyethylene film, A predetermined reinforcing fiber is pressure-impregnated and impregnated into a sheet, which is then rolled and aged at room temperature or under heating to obtain SMC.

Next, the BMC or SMC used when integrally molding the PVC pipe joint with the BMC or SMC by heating and pressing will be described. In this case, the mold temperature must be set to a temperature at which the PVC pipe joint does not deform, that is, 120 ° C or less. Therefore, BMC or SMC having a curing temperature of 40 to 120 ° C., more preferably 60 to 100 ° C., is preferably used. The curing temperature is 100 × 100 using the BMC or SMC in the mold at that temperature.
The molding temperature required to obtain a × 10 mm plate-shaped molded product is 5 to 10 minutes. For example, B with a curing temperature of 80 ℃
MC or SMC means BMC or SMC in which the molding time required to obtain the above molded product in a mold at 80 ° C is 5 to 10 minutes.
That is. At curing temperatures below 40 ° C, the BMC or S
It becomes difficult to store MC for a long period of time, while if it exceeds 120 ° C, the molding time becomes long and the productivity decreases.

For the above reasons, it is necessary that the curing agent used for BMC or SMC in this case is one that reacts at a lower temperature than the curing agent generally used. For example, BMC using unsaturated polyester resin with a curing temperature of 70 ° C.
As the curing agent, a peroxide having a 10-hour half-life temperature of about 40 to 50 ° C. is preferably used.

In addition, during the production of BMC or SMC in this case, the temperature of the raw material mixture needs to be maintained at a low temperature at which the mixture does not harden, and the aging of the raw material mixture also needs to be performed at a low temperature. For example, as a method for producing BMC using an unsaturated polyester resin having a curing temperature of 80 ° C., 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 by mixing the reinforcing fiber and this premix with a Henschel mixer to obtain a mixture, sealing the mixture and aging at 20 ° C. for 1 day is adopted.

Next, a method for manufacturing the FRP reinforced PVC pipe joint will be described. The FRP reinforced PVC pipe joint of the present invention is a PVC pipe joint formed in advance by using BMC or SMC.
It is obtained by reinforcing and integrating with the RP layer. The method of integrating the two is not limited, but a preformed PVC pipe joint is fixed as an insert in a mold, and an integrated molding method in which BMC or SMC is inserted and heated and pressed, and a preformed A preferable method is a method of adhesively joining the formed PVC pipe joint and the preformed FRP reinforcing layer with an adhesive.

First, the constant molding method will be described. A PVC pipe joint previously molded with an injection molding machine or the like is fixed to a mold heated to 40 to 120 ° C, more preferably 60 to 120 ° C, and BM is fixed.
C or SMC (curing temperature 40 to 120 ° C.) is inserted into a mold in a specified amount and then integrally molded under pressure. Mold temperature is 120 ℃
If it exceeds, the PVC pipe joint will be deformed such as blister,
On the other hand, if it is less than 40, the molding time is long and the productivity is low, which is not preferable.

Next, a method of adhesive bonding will be described. BMC or SMC is preheated and pressure-molded with a mold, and FRP
A molded product having the shape of the reinforcing layer or a molded product obtained by dividing the shape of the FRP reinforcing layer into several pieces is obtained. The molded product is bonded and integrated with the reinforcing surface of the PVC pipe joint using an adhesive. The BMC or SMC used in this method has the above-mentioned curing temperature of 40 to 120 ° C.
It is not limited to these, and generally commercially available products which are molded at 120 ° C. or higher can be preferably used.

In the case of integral molding, an adhesive having rubber elasticity after curing is applied to the joint surface of the PVC pipe joint with the FRP reinforcing layer, and an adhesive layer having rubber elasticity is formed between the FRP reinforcing layer and the integrated structure. More preferably, it is molded. Further, it is more preferable that the adhesive used in the method of adhesive bonding also has rubber elasticity after curing. The adhesive layer made of the adhesive firmly joins the PVC pipe joint and the FRP reinforcement layer, and when the internal water pressure is applied to the FRP reinforcement PVC pipe joint, the PVC pipe with cracks generated in the FRP reinforcement layer. It acts to prevent propagation to the joint. Therefore, FRP
The water pressure resistance strength of the reinforced PVC pipe joint is further improved as compared with that without the adhesive. The adhesive is not particularly limited, but a rubber-based adhesive such as a nitrile rubber adhesive or a butyl rubber adhesive, a polyester-based adhesive, a urethane-based adhesive, or the like is preferable.

〔Example〕

Hereinafter, the present invention will be described in more detail based on the preferred examples, but the present invention is not limited to the examples.
Needless to say.

(Manufacture of BMC) 100 parts by weight of unsaturated polyester resin (Polymer 6709, manufactured by Takeda Chemical Industries, Ltd.) 20 parts by weight of calcium carbonate 80 parts by weight of glass chopped strands (13 mm) 5 parts by weight of zinc stearate 2 parts by weight of magnesium oxide Cured Agent (Perkadox 16, 1.5 parts by weight manufactured by Kayaku Nouri Co., Ltd.) First, all raw materials except the above glass chopped strands are blended and mixed with stirring to prepare a preliminary mixture. Next, the glass chopped strands are charged into a cooled Henschel mixer, and the preliminary mixture is further charged and stirred and mixed for about 1 minute. Then, the resulting mixture is taken out of the mixer and sealed at 20 ° C. for about 1 day to be aged for BMC.
Got The curing temperature of the obtained BMC was 70 ° C.

[Embodiment 1] An explanation will be given based on FIG. 1 to FIG.

A flanged socket made of hard vinyl chloride resin with a nominal diameter of 100A (hereinafter abbreviated as PVC flange) 2 is fixed to the lower mold 3 using the middle mold 1. Next, the outer mold 4 heated to 70-80 ℃
Was fixed to the lower mold 3, and immediately the BMC6 obtained above was 600
It is put into the outer mold inner space 5 (Fig. 1). Next, 70-80
The upper die 7 heated to ℃ is fitted into the outer die 4 (second
Figure), hot press heated to 70-80 ℃, molding pressure 50k
Pressurized integral molding was performed under the conditions of gf / cm ² and pressurizing time of 15 minutes (Fig. 3) to obtain an FRP-reinforced RVC flange (Fig. 4).
Figure).

[Example 2] An FRP-reinforced RVC flange was obtained in the same manner as in Example 1 except that a PVC flange having a urethane-based adhesive having rubber elasticity after curing applied to the FRP-reinforced surface was used instead of the PVC flange. It was

[Example 3] SMC (MC214, manufactured by Showa Polymer Co., Ltd.) was inserted into a mold for FRP reinforcing layer molding at 600 g, and then at 150 ° C, molding pressure 100 kgf / cm.
^2. Molded under conditions of pressurizing time 10 minutes, F for PVC flange
An RP reinforcing layer was obtained. Next, a urethane type adhesive having rubber elasticity after curing is applied to the reinforcing surface of the RVC flange, and this and the FRP reinforcing layer are joined and integrated to form an FRP reinforcing P
A VC flange was obtained.

Comparative Example 1 As a thermosetting resin, an unsaturated polyester resin (Yupica
4521, manufactured by Nippon Yupica Co., Ltd.), glass chopped strand mat and glass roving cloth were used as reinforcing fibers, and were laminated on a 100 A PVC flange by a hand layup method to obtain an FRP reinforced PVC flange.

[Comparative Example 2] A glass chopped strand mat is cut into a predetermined shape, a PVC flange of 100 A is covered with the mat, and the mat is covered with a glass table to obtain a prototype.

After inserting the prototype into a resin injection mold,
An unsaturated polyester resin containing a curing agent (Yupica 4540, manufactured by Nippon Yupica Co., Ltd.) was injected from a resin injection port and cured to obtain an FRP reinforced PVC flange.

The thicknesses of the FRP reinforcing layers in the above-mentioned examples and comparative examples were set to be the same.

The FRP-reinforced PVC flanges obtained in Examples and Comparative Examples were compared for workability, appearance, glass fiber distribution, and water pressure resistance. The results are shown in Table 1.

The distribution of the glass fibers was determined by cutting out arbitrary portions of the FRP reinforcing layer, measuring the glass content rate according to JIS K7052, and determining the variation. Further, as shown in FIG. 5, the water pressure resistance strength is such that the FRP reinforced PVC flange 11 is sandwiched between the metal flanges 9 and 10 with the bolts 13 (only one is shown), and the water pressure at 20 ° C. is 10 kgf / min. The water pressure at the time of increasing and breaking at a rate of cm ² was measured by a pressure gauge.

[Effects of the Invention] As described above, the FRP-reinforced PVC pipe joint according to the present invention has very good dimensional accuracy and appearance as compared with the conventional hand lay-up method (stacking method).
Workability and productivity are also improved. Also,
Compared with the conventional RI method, it becomes possible to uniformly fill the ends of the pipe joint having a complicated shape uniformly, and voids are eliminated, and stable physical properties and appearance can be obtained. . Therefore, the FRP-reinforced PVC pipe joint obtained according to the present invention has excellent corrosion resistance because the inner surface is made of PVC, and the reinforcing layer of the flange is FR.
Since it is made of P, it is excellent in heat resistance and strength, and can be used for a long time in transportation pipes for the above-mentioned chemicals having high-temperature corrosiveness, high-temperature hot spring water, and the like.

[Brief description of drawings]

1 to 3 are longitudinal cross-sectional views of a main part of each state showing the FRP-reinforced PVC flange molding method according to Example 1, and FIG. 4 is a partial cutout of the FRP-reinforced PVC flange obtained by the method of Example 1. FIG. 5 is a perspective view showing a method of measuring the water pressure resistance strength of a FRP reinforced PVC flange. 1 ... Medium type, 2 ... PVC flange, 3 ... Lower type, 4 ... Outer type, 5 ... Space, 6 ... BMC, 7 ... Upper type, 8 ... BMC reinforcing layer, 9 ... Metal Flange, 10 …… Metal flange, 11 …… FRP reinforced PVC flange, 12 …… Water inlet, 13 …… Bolt, 14 …… Rubber packing, 15 …… O-ring.

Claims (7)

[Claims] 1. A vinyl chloride resin pipe joint reinforced with a fiber-reinforced thermosetting resin (FRP) layer, wherein the FRP layer is formed by using a bulk molding compound (BMC) or a sheet molding compound (SMC). FRP reinforced vinyl chloride resin pipe fittings characterized by being made. 2. The pipe joint according to claim 1, wherein an adhesive layer having rubber elasticity after curing is provided between the FRP reinforcing layer and the vinyl chloride resin pipe joint. 3. A preformed vinyl chloride resin pipe joint is reinforced and integrated with a fiber reinforced thermosetting resin (FRP) layer using a bulk molding compound (BMC) or a sheet molding compound (SMC). A method for manufacturing an FRP-reinforced vinyl chloride resin joint, comprising: 4. The method according to claim 3, wherein a preformed vinyl chloride resin pipe fitting is fixed as an insert in a mold, and BMC or SMC is further inserted, and then pressure-integrated molding is performed at 40 to 120 ° C. Method. 5. The method according to claim 3, wherein an adhesive having rubber elasticity after curing is applied to the joint surface of the preformed vinyl chloride resin pipe joint with the FRP layer. 6. The method according to claim 3, wherein the preformed vinyl chloride resin pipe joint and the preformed FRP reinforcing layer are joined with an adhesive. 7. The method according to claim 6, wherein the adhesive has rubber elasticity after curing.