JPH0224655B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention mainly relates to fiber-reinforced thermosetting resin-reinforced vinyl chloride resin pipes (hereinafter referred to as
(abbreviated as FRP reinforced PVC pipe). [Conventional technology] Conventionally, to take advantage of the excellent corrosion resistance of vinyl chloride resin pipes (hereinafter abbreviated as PVC pipes), the outer periphery of PVC pipes was directly coated with fiber-reinforced thermosetting resin to improve mechanical strength and heat resistance. Although pipes reinforced with layers (hereinafter referred to as FRP layers) are manufactured, PVC
The adhesive strength between the pipe and the FRP layer was very weak, and the mechanical strength did not satisfy the theoretical strength calculated from the strength of the PVC pipe and the FRP layer, so it could not be used under high temperature and high pressure. Also, PVC
Some pipes are manufactured with an FRP layer attached to the outer circumference of the pipe using an unsaturated polyester resin adhesive or epoxy resin adhesive that has improved adhesion to PVC pipes, but it is not possible to use FRP for these pipes. Due to the low tensile elongation of the adhesive, the mechanical strength, particularly the water pressure strength, did not satisfy the theoretical strength as described above, and it could not be said to be sufficient as a high temperature and high pressure piping material. The applicant previously filed a patent application for a "reinforced thermoplastic resin laminate" containing FRP-reinforced PVC pipes that solved these problems. This application has already been disclosed in Japanese Unexamined Patent Publication No. 59-29156, and as shown in this publication, the FRP-reinforced PVC pipe obtained based on the invention is made of PVC.
It is characterized by a rubber elastic layer containing a thickness retaining material that has adhesive properties between the pipe and the FRP layer, and has superior mechanical strength, especially water pressure strength and heat resistance, compared to the conventional products. It was something I had. [Problems to be solved by the invention] The above-mentioned FRP-reinforced PVC pipe obtained by the applicant's earlier application has excellent corrosion resistance and mechanical strength, especially high water pressure resistance, and is also heat resistant at around 85°C. It had the following characteristics. However, in recent years, as production efficiency has improved, the temperature of various chemical solutions has tended to rise significantly, creating a strong demand for the development of FRP-reinforced PVC pipes with higher heat resistance. In order to meet this demand, the present inventors first
As a result of repeated research on the corrosion resistance of PVC resin at high temperatures, it was found that PVC resin itself has sufficient corrosion resistance at high temperatures of around 95°C, although its mechanical strength decreases. Furthermore, the present inventors developed an FRP that can be used at high temperatures of around 95℃.
As a result of intensive study on adhesives for reinforced PVC pipes,
An adhesive layer with a specific range of tensile elongation and high adhesive strength at high temperatures is provided between the PVC pipe and the FRP layer, and the adhesive is two types of unsaturated polyester resins with different tensile elongations and an isocyanate compound. The present inventors have discovered that it is sufficient to use a material containing as a main component, and have accomplished the present invention. In other words, the object of the present invention is to produce FRP-reinforced PVC that maintains excellent corrosion resistance and mechanical strength, especially water pressure strength, and has a long-term heat resistance temperature of around 95°C.
It is to provide a tube. [Means for Solving the Problems] The measures taken to solve the problems of the prior art are that in an FRP-reinforced PVC pipe in which a PVC pipe is reinforced with an FRP layer, a The tensile elongation rate is 25 to 45% at 23℃, and
An adhesive layer having a tensile shear adhesive strength of 20 kgf/cm ² or more at 95°C between the PVC pipe and the FRP layer is provided, and the adhesive is made of unsaturated polyester having a tensile elongation rate of 50 to 80% at 23°C. The main components are a resin, an unsaturated polyester resin having a tensile elongation of 1 to 6%, and an isocyanate compound. The present invention will be explained in detail below. In the present invention, the FRP reinforced PVC pipe includes a bent pipe,
Also includes joints such as bend cheeses and sockets, and flanges. Examples of the vinyl chloride resin constituting the PVC pipe in the present invention include chlorine resins such as polyvinyl chloride resin and chlorinated polyvinyl chloride resin, and stabilizers, plasticizers, base materials, etc. are added to the resin. Blended resin compositions are also preferably used. Thermosetting resins constituting the FRP layer used in the present invention include unsaturated polyester resins, phenolic resins, epoxy resins, urea resins,
Examples of the reinforcing fibers include melamine resin, diallyl phthalate resin, alkyd resin, silicone resin, and polyimide resin. Examples of reinforcing fibers include organic fibers such as glass fiber, carbon fiber, and aramid fiber. The FRP layer is formed by a hand lay-up method, a spray-up method, a filament winding method, etc. using these thermosetting resins and various reinforcing fibers. In the present invention, the adhesive forming the adhesive layer provided between the PVC pipe and the FRP layer must have a tensile elongation rate of 25 to 45% at 23°C. If the tensile elongation rate is less than 25%
The water pressure strength of the FRP-reinforced PVC pipe did not satisfy the theoretical strength calculated from the strength of the PVC pipe and FRP layer.
The effect of reinforcing the FRP layer is not visible. This phenomenon is particularly noticeable in the case of piping having a complicated shape. In addition, if the tensile elongation rate is greater than 45%, the heat resistance of the adhesive will decrease, and the FRP layer will peel more easily than the PVC pipe at high temperatures around 95°C.
FRP reinforcement with strong bonding of PVC pipe and FRP layer
PVC pipe is not available. In addition, as an adhesive, the temperature is 23℃.
The reason for mixing an unsaturated polyester resin with a tensile elongation rate of 1 to 6%, an unsaturated polyester resin with a tensile elongation rate of 50 to 80%, and an isocyanate compound is that A mixture of a saturated polyester resin and an isocyanate compound has a low tensile elongation rate, and although heat resistance can be obtained, mechanical strength, especially hydrostatic strength, does not reach the theoretical strength, but an unsaturated polyester resin has a tensile elongation rate of 50 to 80%. By mixing the adhesive, the tensile elongation rate of the adhesive can be adjusted to 25 to 45%, which increases the desired mechanical strength, especially water pressure resistance, and
This is because an FRP-reinforced PVC pipe having heat resistance can also be obtained. Tensile elongation rate is determined by completely curing only the adhesive or the unsaturated polyester resin that makes up the adhesive using a curing agent, etc., and producing a tensile test piece with the shape and dimensions shown in Figures 1 and 2. 10 at 23℃
This is the elongation rate at break when a tensile test is performed at a speed of mm/min. In addition, FIG. 1 shows a plan view of the tensile test piece, and FIG. 2 shows a side view seen from the direction of the arrow shown in FIG. 1. Moreover, the adhesive
It is necessary to have a tensile shear adhesive strength of 20Kgf/cm2 ^or more at 95℃.If the strength is less than 20Kgf/ ^cm2 , the FRP layer will be stronger than the PVC pipe when used for a long period at high temperatures around 95℃. This is because it becomes easier to peel off. The adhesive has 1 hydroxyl group of unsaturated polyester resin.
It is preferable to blend the isocyanate compound so that the number of isocyanate groups is 0.5 to 30, more preferably 0.75 to 10. The isocyanate of the compound per one hydroxyl group of the resin
For less than 0.5 pieces and more than 30 pieces, FRP reinforcement with PVC pipe and FRP layer firmly bonded
PVC pipe is not available. The unsaturated polyester resin used in the present invention includes polyhydric alcohol and unsaturated polybasic acid,
Any ester compound with a saturated polybasic acid or a saturated polybasic acid may be used, and it is dissolved in a monomer that can be copolymerized with an unsaturated bond such as styrene. Furthermore, a polymerization inhibitor and other additives may be added. The isocyanate compound used in the present invention is a compound having an isocyanate group in its molecule, and needs to be a compound having two or more isocyanate groups in one molecule. The compounds include hexamethylene diisocyanate trimer, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, reaction product of 3 mol of hexamethylene diisocyanate and 1 mol of trimethylolpropane, triphenylmethane-4,4',4''-triisocyanate, Examples include tris-(p-isocyanate phenyl) thiophosphate, which can be used alone or as a mixture of two or more, and if necessary, diluted with a solvent such as ethyl acetate or methylene chloride can also be preferably used. Incidentally, in order to speed up the curing speed and sufficiently proceed with curing, it is necessary to add a peroxide such as methyl ethyl ketone peroxide or benzoyl peroxide as a curing agent to the adhesive.Also, a curing accelerator Metal soaps such as cobalt naphthenate and manganese naphthenate may also be blended as a binder.Also, the order of mixing each adhesive compound is not particularly limited, but It is preferable to add a curing agent after mixing two types of unsaturated polyester resins with different elongation rates and an isocyanate compound.The adhesive used in the present invention may be applied to the PVC pipe as it is, but it can be applied to the PVC pipe by penetrating it into the thickness maintaining material. It is preferable to apply it together with a retaining material.As the thickness retaining material, for example, glass, carbon, polyacrylonitrile, acetalized polyvinyl alcohol (vinylon), fibers such as polyamide and polyester, woven fabrics such as linen, cotton, silk and cellulose, or , nonwoven fabric, or porous materials such as Japanese paper.The method for manufacturing the FRP-reinforced PVC pipe in the present invention is not particularly limited, but for example, it can be manufactured by the following method.Pre-extrusion After the outer circumference of the PVC pipe obtained by molding etc. is sandblasted, an adhesive mainly composed of two types of unsaturated polyester resins with different tensile elongation rates and an isocyanate compound is applied, gelled, and then glass fiber An FRP-reinforced PVC pipe can be obtained by laminating the pipes while impregnating them with an unsaturated polyester resin and curing them at room temperature or under heating. The invention is not limited to these Examples in any way. In the Examples below, the tensile shear adhesive strength, hydrostatic fracture strength, etc. were measured by the following test methods. (1) Tensile shear adhesive strength obtained A test piece with the shape and dimensions shown in Figures 3 to 5 was prepared from the FRP-reinforced PVC pipe, and
23℃ and 95℃ by method according to JIS-K6850
Measured at °C. In addition, FIG. 3 shows a horizontal side view of the test piece, FIG. 4 shows a vertical side view, and FIG. 5 shows a plan view.
3 indicates the adhesive layer and 3 indicates the PVC layer. (2) Tensile shear adhesive strength after long-term high temperature treatment After treating the obtained FRP-reinforced PVC pipe at 100℃ x 1000 hours or 120℃ x 1000 hours,
Processed into test pieces with the shape and dimensions shown in Figures 3 to 5, and by a method according to JIS-K6850.
Measured at 23°C. (3) Hydraulic pressure rupture strength A jig as shown in Figure 6 was attached to the obtained FRP-reinforced PVC pipe, the inside of the pipe was filled with water at 20°C, and water pressure was applied at a rate of 10 kgf/cm ² per minute. Raise,
The water pressure at the time the pipe broke was measured. In Figure 6, 1 is the FRP layer, 2 is the adhesive layer, 4 is the PVC pipe, 5 is the PVC flange, and 6
indicates putty, 7 indicates steel flange, and 8 indicates water pressure. Example 1 After the outer periphery of a PVC pipe with a nominal diameter of 75 mm, wall thickness of 6.0 mm, and length of 2 m was sandblasted, an adhesive having the composition shown below was applied to the outer periphery of the PVC pipe and gelled at room temperature. , glass chopped strand mat 2 whose outside was further impregnated with unsaturated polyester resin (Yupica 4521PT, manufactured by Nippon Upica Co., Ltd.)
An FRP layer (thickness: 2.7 mm) consisting of one layer of glass roving cloth and one layer of glass yarn cloth was laminated. This was left at 50°C for 48 hours to completely cure the adhesive and the unsaturated polyester resin,
The desired FRP reinforced PVC pipe was obtained. obtained
Table 1 shows the results of measuring the tensile shear adhesive strength, the tensile shear adhesive strength after long-term high temperature treatment, and the hydraulic fracture strength of the FRP-reinforced PVC pipe. ●Unsaturated polyester resin A containing styrene monomer [Yupica 8671, tensile elongation rate: 62%, manufactured by Nippon Upica Co., Ltd.] 50 parts ●Unsaturated polyester resin B containing styrene monomer [Yupica 4521PT, tensile elongation rate: 2.6% , manufactured by Nippon U-Pica Co., Ltd.] 30 parts ● Isocyanate compound [trimer of hexamethylene diisocyanate, Coronate EH, manufactured by Nippon Polyurethane Industries Co., Ltd.] 20 parts ● Methyl ethyl ketone peroxide 55% dimethylene phthalate solution [Kayametsuku A, Chemical Manufactured by Yaku Nouri Co., Ltd.] (hereinafter abbreviated as MEKPO) 1.5 parts Cobalt naphthenate 6% solution (hereinafter abbreviated as Na-Co) 0.5 parts From Table 1, the tensile elongation rate of the adhesive is 32%. Therefore, the hydraulic rupture strength maintains the theoretical strength (170 Kgf/cm ² ) both at the initial value and after treatment at 95° C. for 1000 hours, and the heat resistance of the adhesive strength is also good. Examples 2 and 3 FRP-reinforced PVC pipes were obtained in the same manner as in Example 1, except that the adhesive shown in Table 1 was used instead of the adhesive used in Example 1. Example 4 The same method as Example 1 was used except that a polyester nonwoven fabric was used as a thickness retaining material for the adhesive layer.
FRP reinforced PVC pipe was obtained. Table 1 shows the measurement results of each strength of the FRP-reinforced PVC pipes obtained in Examples 2 to 4. From Table 1, similar to Example 1, the heat resistance of hydraulic fracture strength and adhesive strength is good. Comparative Examples 1 to 5 FRP-reinforced PVC pipes were obtained in the same manner as in Example 1, except that the adhesive shown in Table 1 was used instead of the adhesive used in Example 1. However, in Comparative Example 5, a polyester nonwoven fabric was used as a thickness retaining material for the adhesive layer. Obtained FRP reinforcement
Table 1 shows the results of each strength of the PVC pipe. From Table 1, the results obtained in Comparative Example 1 and Comparative Example 2
Since the tensile elongation rate of each adhesive used in FRP reinforced PVC pipes is less than 25%, the heat resistance of adhesive strength is good, but the initial value of water pressure resistance does not satisfy the theoretical strength. After treatment at 95°C for 1000 hours, the decrease was even greater. In addition, the FRP-reinforced PVC pipe obtained in Comparative Example 3 was
The tensile elongation rate of the adhesive used is greater than 45% and the adhesive has low heat resistance, so the initial value of the hydraulic fracture strength satisfies the theoretical strength, but at 95℃
After 1000 hours of treatment, the PVC pipe and FRP layer peeled off. Furthermore, the FRP-reinforced PVC pipe obtained in Comparative Example 4 had low adhesive strength between the PVC pipe and the FRP layer because the adhesive used did not contain an isocyanate compound, and was treated at 95°C for 1000 hours. This caused the PVC pipe and FRP layer to separate. The FRP-reinforced PVC pipe obtained in Comparative Example 5 has been used at 85℃ for a long time without any problems, but the hydraulic fracture strength does not exceed the theoretical value even after treatment at 95℃ for 1000 hours. The tensile shear adhesive strength at 23°C and 95°C was also as high as that of Examples 1 to 4.
Although it has the same strength as 100℃ and 120℃
The adhesive strength decreased significantly after each treatment at ℃ for 1000 hours.

【table】

【table】

[Table] Example 5 A chemical resistance test piece with the shape and dimensions shown in Figure 7 was prepared using the same adhesive as in Example 1, and the shape and dimensions shown in Figure 8 were prepared by adding saturated chlorine water at 20°C. immersed in a test container and sealed. In addition, FIG. 7 shows a cross-sectional view of the test piece, in which reference numeral 1 indicates the FRP layer, 2 indicates the adhesive layer, 9 indicates the PVC plate, and 11 indicates the PVC welded part.
Moreover, FIG. 8 shows a cross-sectional view of the test container, and the reference numeral 1
2 is SUS lid, 13 is PVDF lid, 14 is PVDF
15 is a container made of SUS, 16 is a covered packing made of
PVDF container 17 indicates saturated chlorine water. Place the test container in a constant temperature bath at 95℃ and leave it for a specified number of days.
Take out the test piece, cut it from the center, and attach it to a PVC plate.
While observing the adhesion state with the FRP layer,
The discolored portion of the liquid contact area was measured as the erosion thickness using a microscope. No deterioration of PVC was observed except for discolored areas. The saturated chlorine water was replaced once every two days. The test results obtained are shown in Table 2. Moreover, the relationship between the erosion thickness and the number of days of immersion is shown in FIG.

〔Effect of the invention〕

According to the present invention obtained in Examples 1 to 4 described above
When compared with the FRP-reinforced PVC pipe according to the applicant's earlier invention obtained in Comparative Example 5, there is no significant difference in tensile shear adhesive strength at 23°C and 95°C, but on the other hand, at 100°C and 120℃ respectively
The strength after treatment for 1000 hours is very good, especially at 120°C. Furthermore, it is generally known that PVC tends to undergo thermal decomposition at high temperatures of 100°C or higher, making it difficult to use it for long periods at temperatures above this temperature. From the above, it is determined that the long-term heat-resistant temperature of the FRP-reinforced PVC pipe of the present invention is around 95°C, which is higher than the long-term heat-resistant temperature of 85°C according to the applicant's prior invention.
It can be seen that the temperature is about 10℃ higher than that of ℃. In addition, the PVC pipe used in the present invention
Since the adhesive with the FRP layer has a high tensile elongation rate,
The resulting FRP-reinforced PVC pipe has an excellent hydraulic rupture strength equivalent to that of the FRP-reinforced PVC pipe according to the applicant's earlier invention. Furthermore, the FRP reinforced PVC pipe obtained in the present invention is
It also has excellent corrosion resistance at high temperatures around 95℃.
For example, as shown in Example 5, for saturated chlorine water, the erosion thickness after 10 years of use at 95°C is 0.8 from the semi-logarithm graph of erosion thickness and immersion days in Figure 9.
It is expected to be around mm, indicating that it can be used for a sufficiently long period of time. As explained above, according to the present invention, it is possible to obtain an FRP-reinforced PVC pipe that has excellent corrosion resistance, high mechanical strength, particularly high hydraulic fracture strength, and excellent long-term heat resistance. Since the FRP-reinforced PVC pipe obtained by the present invention has the above-mentioned effects, it can also be used for transportation piping for corrosive fluids such as chlorine water, hydrochloric acid, nitric acid, and sulfuric acid, which have a high temperature of around 95°C. It became.

[Brief explanation of drawings]

Figure 1 is a plan view of a test piece for determining the tensile elongation rate of the adhesive layer, Figure 2 is a side view as seen from the arrow direction in Figure 1, Figures 3, 4 and 5 are PVC
This figure shows the structure of a test piece for determining the tensile shear adhesive strength between a pipe and an FRP layer. Figure 3 is a lateral side view of the test piece, Figure 4 is a longitudinal side view, and Figure 5 is a plan view. Figure 6 is a longitudinal cross-sectional view of the device for determining the hydraulic fracture strength of FRP-reinforced PVC pipes;
The figure is a cross-sectional view of a chemical resistance test piece, Figure 8 is a cross-sectional view of a chemical resistance test piece and a chemical resistance test container containing saturated chlorine water, and Figure 9 is a cross-sectional view of a chemical resistance test piece and a chemical resistance test container containing saturated chlorine water. It is a figure showing the relationship between thickness and immersion days. 1...FRP layer, 2...adhesive layer, 3...PVC
Layer, 4...PVC pipe, 5...PVC flange, 6...
...Putty, 7...Steel flange, 8...Water pressure, 9...
...PVC board, 10...PVC pipe, 11...PVC
Welded part, 12... SUS lid, 13... PVDF lid, 14... PVDF coated packing, 15... SUS
Container made of 16...PVDF container, 17...Saturated chlorine water.

Claims (1)

[Scope of Claims] 1. In a fiber-reinforced thermosetting resin-reinforced vinyl chloride resin pipe in which a vinyl chloride resin pipe is reinforced with a fiber-reinforced thermosetting resin layer, the vinyl chloride resin pipe and the fiber-reinforced thermosetting resin layer The tensile elongation rate is 23 between
Provide an adhesive layer having a tensile shear adhesive strength of 25 to 45% at 95°C and a tensile shear adhesive strength between the vinyl chloride resin pipe and the fiber-reinforced thermosetting resin layer of 20 Kgf/cm ² or more at 95°C, and the adhesive but 50-80% at 23℃
A fiber-reinforced thermosetting resin-reinforced vinyl chloride resin pipe characterized in that the main components are an unsaturated polyester resin having a tensile elongation of 1 to 6%, and an isocyanate compound. . 2 Hydroxyl group of unsaturated polyester resin as adhesive 1
The fiber-reinforced thermosetting resin-reinforced vinyl chloride resin pipe according to claim 1, characterized in that the isocyanate group of the isocyanate compound is blended at a ratio of 0.5 to 30 to . 3. The fiber-reinforced thermosetting resin-reinforced vinyl chloride resin pipe according to claim 1 or 2, wherein the adhesive layer contains a thickness maintaining material.