JPS61213136A - Continuous pultrusion method of frp pipe - Google Patents

Abstract

PURPOSE:To improve dimensional accuracy, by a method wherein an external shape of an FRP layer is fixed by passing through a shaping die fitted to an impregnation tank and a shaping ring device in front of a ultraviolet-curing furnace and curing of only a surface layer is performed in the inside of the ultraviolet-curing furnace. CONSTITUTION:A vinyl chloride pipe is extruded through an extruding machine 1, which is made to cure into a circular form by passing under water in the inside of a cooling tank 2 while sizing is being performed and pulled out through a pulling machine 3. Glass roving provided on rests 4, 4 is made to fit to the external circumference of a vinyl chloride pipe P1 in a manner of running along the pipe and made to impregnate in an impregnation tank 5. As the glass roving 37 is wound over the external circumference of a pipe P2 which have shifted to a winder 7 and pressed by rubber sheets 41, 41, also the glass roving 37 is impregnated with unsaturated polyester resin. An external shape is fixed by passing a reinforcement pipe P3 through a shaping ring device 49 and a surface layer is made to cure by passing the pipe P3 through ultraviolet curing furnaces 8a, 8b, 8c. The inside of the same is made to cure by a far infrared furnace 9, water-cooled in a cooling tank 11 after the inside of a mold 10 of the extruding machine has been coated with polyethylene, and made to cure by a curing furnace 15 after the same has been pulled out by a pulling machine 12.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is used in the field of manufacturing FRP pipes, and is used to manufacture various FRP pipes.
This article relates to a continuous pultrusion method for FRP pipes that efficiently produces pipes.

(Prior art) As a conventional continuous pultrusion method for FRP pipes,
As described in Publication No. 6-166030.

An uncured thermosetting resin is applied onto the core material, passed through an ultraviolet curing oven, shaped into the desired external shape, and cured to the extent that the surface layer does not deform. Technological means are disclosed for curing and producing thermoplastic tubes at approximately the same speed as conventional thermoplastic tubes.

(Problems to be Solved by the Invention) However, this conventional continuous pultrusion method for FRP pipes has the following problems.

A long transparent die (tube) is passed through the ultraviolet curing furnace,
The feature is that the outer shape of the FRP pipe is adjusted by passing it through this transparent die, and at the same time, the surface layer of the thermosetting resin layer is cured with ultraviolet rays, and this action is continuously performed to adjust the outer shape of the FRP pipe. 1. As a result of the inventors of the present application manufacturing such an ultraviolet curing furnace and actually attempting to continuously mold FRP pipes, uncured thermosetting resin adhered to the inside of the transparent die, and this hardened naturally. Even when attempting to pultrude the FRP pipe, a large resistance was encountered, and the frictional resistance increased to the point that the FRP pipe could not be pulled out within a short period of time, making it completely unsuitable for practical use.

In other words, it has been found that it is impossible to perform the two functions of shaping the outer shape and curing the surface layer of the thermosetting resin layer using a transparent die in an ultraviolet curing oven.

(Means for Solving the Problems) The present invention has been made to solve the problems of the prior art, and its purpose is to accurately and continuously mold the external dimensions of FRP pipes. The purpose of the present invention is to provide a continuous pultrusion method that allows continuous pultrusion, and as a technical means to achieve this purpose, the present invention includes an inner core layer forming process in which the core material is continuously formed by extrusion, and A glass roving impregnated with a thermosetting resin composition is surrounded along the axial direction around the outer periphery of the core material, and then glass fiber is wound obliquely on top of this and passed through an ultraviolet curing furnace and a far infrared curing furnace. A continuous FRP pipe consisting of a series of continuous processes including a coating layer forming process in which a thermoplastic resin is extruded and coated on the surface of the FRP layer and cooled and taken off. In the pultrusion molding method, the outer shape of the FRP layer is adjusted through a shaping die installed in the immersion tank and a shaping ring device installed in front of the ultraviolet curing furnace, and in the ultraviolet curing furnace. A configuration was adopted in which only the surface layer of the FRP layer was hardened.

(Function) Therefore, in the present invention, only the surface layer of the FRP layer is cured in an ultraviolet curing furnace, and the glass roving and thermosetting resin are uniformly applied to the outer periphery of the core material using a die attached to the impregnation tank. While adhering, the outer shape is adjusted, and then a shaping ring device made of an elastic material installed just before the ultraviolet curing oven applies squeezing force from the outside of the FRP layer to remove air from the FRP layer. , the outer shape is precisely arranged, so FR in the ultraviolet curing furnace
FRP with unprecedented dimensional accuracy without P clogging
Tubes can be produced continuously while increasing the linear speed.

(Example) Examples of the continuous pultrusion method of the present invention will be described below.

The inner core layer forming process is a process in which a thermoplastic resin tube is continuously produced by extrusion molding, then cooled by water cooling, and the inner tube is taken off at a constant speed.

Here, the thermoplastic resin pipe refers to an extruded pipe with high heat resistance such as an ABS resin pipe, an AS resin pipe, and a vinyl chloride resin pipe.

Next, in the FRP layer forming process, the thermosetting resin composition is supplied to the impregnation tank from the resin automatic supply device that automatically mixes and supplies the thermosetting resin with a catalyst and a curing agent. a glass roving impregnated with a thermosetting resin composition through the inner core layer, surrounding the outer periphery of the inner core layer along the axial direction;
The glass roving is passed through a shaping die into close contact with the inner core layer, and then the glass roving or glass yarn is wound diagonally on top of the glass roving, and then the outer shape is adjusted through an elastic shaping ring device. This is a process in which internal curing is performed using infrared rays.

Here, as the thermosetting resin, a liquid material of a polymer of an unsaturated polyester resin, an unsaturated monocarboxylic acid vinyl ester resin, an unsaturated epoxy resin, and styrene or the like is usually used.

The additives used in the present invention are benzoin-based, azo-based, and diphenyl sulfide-based photopolymerization initiators for surface curing with ultraviolet rays, and include styrene monomer 31ii%, toluene 14fi%, and phthalate dioctyl 29% by weight. %, a mixture of 26% by weight of monosubstituted benzene compounds having ether and carboxyl groups is preferably used.

Examples of polymerization accelerators and curing catalysts include tertiary amines and metal catalysts such as cobalt naphthenate.9 Examples of polymerization catalysts include t-butyl peracetate, t-butyl pervivalate, and t-butyl perisobutyl. ester, methyl ethyl peroxide, benzoyl peroxide, t-butyl perbenzoate and the like.

Further, in order to reduce shrinkage during curing, low-shrinkage agents include saturated polyester, polymethyl methacrylate and copolymers, polyvinyl methacrylate and copolymers, and the like.

Next, in the coating layer forming process, a thermoplastic resin with excellent weather resistance such as polyethylene resin, polyvinyl chloride resin, or AES resin is extruded and coated on the surface of the FRP layer, and then the cooled tube is cooled with water. This is a process in which the material is taken at a constant speed.

Next, in the cutting process, the above-mentioned continuously manufactured inner core layer, FR
This method automatically cuts a composite pipe consisting of a P layer and a coating layer to a certain length.

Next, the post-curing process is to harden the cut FRP pipe to near complete hardening and stabilize various physical properties.
It is a 15m tunnel-type post-curing furnace, and the temperature inside the furnace is 5.
Keep the temperature between 0 and 65℃ and place the FRP pipe to-1 in this furnace.
This is a process of leaving it in for about 4 hours.

The method for molding an FRP pipe according to the present invention has been described above.According to the present invention, the outer shape of the FRP pipe can be precisely adjusted using a shaping die and a shaping ring device, and moreover, continuous molding can be performed.

In addition, because it is completely cured, it can be used as a product immediately after production, and because it contains a low-shrinkage agent even when passed through high-temperature fluid, the shrinkage rate is one-tenth that of regular products, so it can be used in cold and heat applications. No peeling from the laminated surface due to repeated use, 130℃
It can be used as a transport pipe for nearby high-temperature areas.

Next, one example of a specific implementation of the method of the present invention will be explained based on the drawings. Wall thickness 1.5++
+m vinyl chloride pipe is extruded at a speed of 5 m/min, passed through water in a cooling tank z, hardened into a circular shape while sizing, and pulled out under tension 41!3.

Subsequently, 74 glass rovings installed on the glass roving mounts 4.4 are attached so as to surround the outer periphery of the PVC pipe P1 in the axial direction, and the impregnating device 5 is impregnated with the glass rovings.

Incidentally, an automatic supply device 6 for automatically measuring and mixing the unsaturated polyester resin, a curing accelerator, a catalyst, etc. is installed adjacent to the impregnation device 5.

A lattice-shaped pedestal 16 is erected at the forefront of the impregnation device 5,
Behind it, as shown in FIG. 3, there is a through hole 17 in the center through which the PVC pipe PL is passed, and a large number of small holes 19 that converge the glass rovings 18 at equal intervals around the outer periphery of the through hole 17. A perforated focusing plate 20 is set upright, and an impregnating tank 21 is installed behind this focusing plate 20.

As shown in FIG. 4, the impregnation tank 21 has a bottom formed into a substantially housing-like body, has an open top surface, and has tension plates 22 installed at two locations inside the housing to apply a tensile force to the glass roving 18. A shaping die 23 is attached to one side.

The shaping die 23 has a length of 55s+, as shown in FIG.
Using a die with an inner diameter of 42 mm and an aperture angle of 5 degrees, insert a glass roving impregnated with a thermosetting resin onto the outer periphery of the PVC pipe from the die center 23a, surrounding it, and insert the die inside 23b. While squeezing the resin layer to remove the air contained in the resin and squeezing out excess resin, the resin and glass roving are pressed onto the vinyl chloride pipe to form a nearly perfect circle.

Next, the automatic resin supply device ai6 is provided with an air cylinder 24 above as shown in FIG. Fix the hanging and mixer 2
A tube 28 for supplying thermosetting resin (unsaturated polyester resin) to 6, a photopolymerization initiator (benzoin ethyl ether 1% by weight), a polymerization accelerator (cobalt naphthenate 0.1% by weight), and a curing catalyst (methyl ethyl ketone) A pipe 29 for supplying peroxide (2.5% by weight) and the like and a pipe 30 for supplying a solvent are installed independently.

The automatic supply device 6 is configured to be interlocked with a level adjustment device a132 using a float 31 installed above the impregnation tank 21, and when the amount of the unsaturated polyester resin composition in the impregnation tank 21 decreases, the flow rate increases. 31 is lowered, the switch 33 is pressed to operate the air cylinder 24, the piston rod 25 is pushed out, and the nozzle 27 is moved into the impregnation tank 21. When the impregnating tank 21 is filled with polyester resin, the float 31 rises upwards and presses the switch 34 to retract the piston rod 25 of the air cylinder 24, supplying the solvent from the pipe 30 and supplying the mixer 26.
and cleaning the inside of the nozzle 27.

Therefore, the glass roving 18 is impregnated with an unsaturated polyester resin by the impregnating device 5, and after its outer shape is adjusted by the shaping die 23, it is transferred to the wine goo (winding machine) 7.

The wine goo (winding machine) 7 is the shaping die 2 of the impregnating device 5.
A bobbin 38.38, around which a glass roving 37 is wound, is attached to a support rod 36, which is configured to rotate around the reinforced vinyl chloride vibe P2 coming out of the PVC vibrator P2 from the base end, and protrudes laterally from the support plate 35 at the base end. 38 is attached so that it can rotate, and at the rear is a glass presser g that rotates around the same reinforced vinyl chloride pipe P! 139 is installed.

This glass holding device 39 has a holding plate 42.42 to which a rubber plate 41.41 is fixed, protruding inward from the base end 40, and this rubber plate 41.41 is attached to a reinforced vinyl chloride pipe P.
, and the glass roving 37 is rotated by being lightly pressed from above.

Therefore, a glass roving 37 is wound around the outer periphery of the reinforced vinyl chloride pipe P, which has been transferred to the wine goo (winding machine) 7, at an angle of about 60 degrees with respect to the pipe axis, and a rubber plate 41, 41 Since the glass roving 37 is also impregnated with the unsaturated polyester resin.

Then, this reinforcing pipe P is passed through a shaping ring device 149 to completely shape the outer shape of the first reinforcing pipe PJ.

As shown in FIG. 6, the shaping ring device 49 is
Support plates 51 and 51 are attached to the support plate 51 at intervals of about 100 mm, and a rubber plate 53 in which shaping holes 52 of 35 sue are bored is attached to the support plate 51. This shaping ring device 49
When the above-mentioned reinforced pipe is passed through, since the forming hole 52 of the rubber plate 53 is formed smaller than the outer diameter of the reinforced pipe P, the elastic force of the rubber plate 53 acts and the reinforced pipe P, Excess resin is removed, the unevenness of the wound glass roving 37 is smoothed, and the outer shape of the reinforced pipe PJ is adjusted to a circular shape.

Next, the reinforcing pipe adjusted into a circular shape by the shaping ring device 49 is passed through the ultraviolet curing furnaces 8a, 8b, and 8c.

At this time, in this example, the pipe is moved at a rate of 5 m/min, and the pipe is moved at a rate of 2 m/min.
The surface layer of the unsaturated polyester resin impregnated into the reinforcing pipe P is passed through an ultraviolet curing oven 8a at 90°C, then transferred to an ultraviolet curing oven 8b at 310°C, and then transferred to an ultraviolet curing oven 8c at 320°C, within a few seconds. harden with.

As shown in FIG. 7a, the ultraviolet curing furnace 8a has four
4 high-pressure mercury lamps 43a are placed diagonally across the reinforcing pipe Pj.
This is installed to cure the surface layer of the unsaturated polyester resin with ultraviolet rays, and the ultraviolet curing furnace 8b is the seventh one.
As shown in the figure, two high-pressure mercury lamps 43b are installed at two positions on the left and right, and the ultraviolet curing furnace 8C is equipped with two high-pressure mercury lamps 43c at two positions above and below, as shown in FIG. 7C.

Next, after curing one surface layer, the process moves to a far-infrared curing furnace 9, where, as shown in FIG. 8, a far-infrared heater 45.
45 are long in the axial direction of the reinforcing pipe P1 and are attached above and below the reinforcing pipe P, and the inside of the polyester resin layer is heated and hardened.

Next, after exiting the far-infrared curing furnace 9, this reinforcing pipe Pj is passed through the crosshead mold IO of an extruder for extruding polyethylene resin, and the outer periphery is coated with approximately 0.75 mm of polyethylene, and then the cooling tank 11 The coating layer was water-cooled by passing through the
After being pulled out at 1112, the marking device 13 prints the manufacturer's name, loft number, etc. on the surface of the pipe, and the cutting machine 14 cuts the pipe into required dimensions. After that, the unsaturated polyester resin was heated at 55°C for 10 hours to completely cure the unsaturated polyester resin.
Complete P.

As shown in Fig. 1θ, the FRP pipe P thus formed is attached to a glass roving 37 wound in the same direction as the glass roving 18 with the inner core layer 46 attached to vinyl chloride resin and the intermediate layer 47 attached in the axial direction. It is constructed as a composite tube with a three-layer structure including a reinforced plastic layer impregnated with a saturated polyester resin and hardened, and an outer layer 48 coated with a thermoplastic resin.

In the post-curing furnace 15, an air flow passage 55 is taken out from one end of the ceiling wall surface of a tunnel-shaped furnace body 54 that accommodates a large number of reinforced pipes P coated with polyethylene resin and having a length of approximately 10 m. blower 56, heat exchanger 5
7. A heating chamber 58 is provided therein, and a terminal end 55 of an air flow passage 55' from the heating chamber 58 is penetrated into the furnace from the ceiling wall at the other end of the furnace body 54, and a 7-door 59 is attached to and detached from the terminal end 55'. The trolley 6 can be mounted in the tip opening 60 of the hood 59.
Insert the pipe end of the reinforced pipe P loaded on the hood 5, tighten and seal the opening 60, and blow the 55°C warm air W into the hood 5.
9 into the conduit of each pipe P, and is formed so as to be efficiently cured while being heated.

The outer diameter of the FRP pipe P formed as explained above was all adjusted within 41.50 ± 0.3, and it was possible to manufacture it with almost the same outer diameter accuracy as that of a normal vinyl chloride pipe. . In addition, by using a post-curing furnace, products can be used immediately after production, the quality is stable, and productivity can be achieved at a linear speed comparable to that of ordinary PVC pipes. There is no clogging of pipe P4 in the ultraviolet curing furnace, and mass production is now possible.

[Brief explanation of the drawing]

Fig. 1 is a side view of an apparatus for forming FRP pipes by the method of the present invention, Fig. 2 is a perspective view of an automatic feeding device of the present invention, Fig. 3 is a front view of a bundle plate of the present invention, and Fig. 4 is an impregnation Enlarged cross-sectional view of the tank,
FIG. 5 is a partial cross-sectional side view of the shaping die of the present invention, FIG. 6 is a cross-sectional view of the shaping ring device, FIG. 7 is a cross-sectional view of an ultraviolet curing furnace, and FIG. 8 is a cross-sectional view of a far-infrared curing furnace. 9 is a partially cutaway side view of the post-hardening furnace of the present invention, and FIG. 10 is a perspective view of an FRP pipe formed by the method of the present invention. l: Extruder 2: Cooling tank 3: Tensile machine 4 Nigara throbbing frame 5: Impregnation device 6: Automatic feeding device 7: Wine goo 8a, 8b, 8c: Ultraviolet curing furnace 9: Far infrared curing furnace 10: Crosshead mold 15: Post-hardening furnace 23: Shaping die 49: Shaping ring device

Claims (1)

[Claims] 1) An inner core layer forming process in which the core material is continuously formed by extrusion molding, and a glass roving impregnated with a thermosetting resin composition is surrounded along the axial direction around the outer periphery of the core material in an impregnation tank. Then, the FRP layer forming process is performed by winding the glass fiber diagonally from above and hardening it from the surface and inside through an ultraviolet curing furnace and a far infrared curing furnace.
F consists of a continuous series of processes including a coating layer forming process in which the surface of the RP layer is extruded and coated with thermoplastic resin and then cooled and taken off.
In the continuous pultrusion method for RP pipes, the outer shape of the FRP layer is adjusted through a shaping die installed in the impregnation tank of the above FRP layer forming process and a shaping ring device installed in front of the ultraviolet curing furnace, and then A continuous pultrusion method for an FRP pipe, characterized in that only the surface layer of the FRP layer is hardened.