JPH03393A - Heat-resisting frp pipe - Google Patents

Abstract

PURPOSE:To improve high temperature strength by reacting a starting material consisting of a mixture of a condensation polycyclic aromatic compound and a monocyclic aromatic compound with a cross-linking agent consisting of hydroxymethyl by the use of an organic sulfonic acid compound as a catalyst. CONSTITUTION:As the starting material of resin, a mixture of a condensation polycyclic aromatic resin and a monocyclic aromatic compound is used. The condensation polycyclic aromatic compounds include naphthalene and various benzopyrene. The monocyclic aromatic compounds include phenol and alkyl phenols. A cross-linking agent is an aromatic compound having two hydroxymethyl group or halomethyl groups such as benzene and xylene. Such starting material is reacted with the cross-linking agent in the presence of an acid catalyst, and as the acid catalyst, organic aromatic sulfonic acids and hydroxymethyl group are used. The used amount of the acid catalyst is preferably about 1-20wt.%, and the mixing ratio of the cross-linking agent to the cross-linked agent (starting material + acid catalyst) is preferably about 0.7-6 by molar ratio.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to FRP pipes (fiber-reinforced plastic pipes) with excellent heat resistance. Regarding 11F RP pipe.

(Conventional technology) FRP pipes are lightweight, have high strength, and have excellent corrosion resistance, and are used for everything from general piping for hot springs, chemical plants, electric power, and steel manufacturing facilities, to line pipes for transporting crude oil and natural gas, and for crude oil drilling. It is widely applied to high-pressure piping such as oil country tubular goods.

Conventionally, thermosetting resins such as unsaturated polyester resins and epoxy resins have been used as matrix resins for FRP pipes.

Although FRP pipes made using these resins have the advantage of being lightweight and having excellent corrosion resistance, they have the disadvantage that they do not have sufficient heat resistance and can only be used at relatively low temperatures below 100°C. . For example, the heat distortion temperature is 130°C or less for unsaturated polyester resins and 150°C or less for epoxy resins.If the temperature exceeds 100°C, the strength decreases significantly, so it is not suitable for application in high temperature ranges exceeding 100°C. (For example, see page 18 of ``rFRP Design Handbook.'')

Resins with excellent heat resistance include polyetheretherketone (PEEK) and polyethersulfone (PEs), but these are expensive and are thermoplastic resins, so the filament winding method has the best strength properties. and similar laws are not applicable. It is also known that polyimide, which is a thermosetting resin with the highest heat resistance, is used as a matrix resin.
This resin has the drawbacks of being extremely expensive and having poor moldability.

(Problems to be Solved by the Invention) In view of the above-mentioned actual situation of FRP pipes, the present invention provides an FRP pipe that uses a relatively inexpensive thermosetting resin as a matrix resin and has excellent heat resistance, that is, high-temperature strength. be.

(Means for Solving the Problems) The present inventors have developed a recently developed condensed polycyclic aromatic resin (Condensed PNA resin) named C0PNA resin.
a1y-Nuclear Aro@atic Re5i
n+ See JP-A-62-521 and JP-A-62-522, a crosslinking agent consisting of a condensed polycyclic aromatic compound such as naphthalene and an aromatic compound having at least two hydroxymethyl or halomethyl groups is combined with an acid catalyst. We focused on the fact that resins obtained by reacting in the presence of phenols (resins obtained by reacting in the presence of phenols) and resins modified with monocyclic aromatic compounds such as phenol are thermosetting resins that are relatively inexpensive and have excellent heat resistance. F
An attempt was made to use it as a matrix resin for RP pipes. However, although it is possible to obtain FRP pipes with excellent heat resistance by simply applying conventional resins of this type, there are problems such as inability to form due to fogging of the mold and inability to extract due to corrosion of the mandrel surface. It has been found.

Further research revealed that this problem was caused by the acid used as a catalyst oozing out to the surface due to condensation water generated during curing, reacting with the metal in the mold, and producing metal salts. We discovered that the above problem could be avoided by using an acid catalyst that is reactive with the raw material components to immobilize the acid on the resin skeleton during production, or by using a water-insoluble acid catalyst, and completed the present invention. did.

Here, the gist of the present invention is to provide a raw material consisting of a fused polycyclic aromatic compound or a mixture of a fused polycyclic aromatic compound and a monocyclic aromatic compound, and an aromatic material having at least two hydroxymethyl groups or halomethyl groups. A crosslinking agent consisting of a group compound is reacted with an organic sulfonic acid compound having reactivity with at least one of the raw material or the crosslinking agent, or a water-insoluble organic sulfonic acid compound or a sulfonic acid group-containing polymer as a catalyst. This is a heat-resistant FRP pipe characterized in that the thermosetting condensed polycyclic aromatic resin obtained by the above method is used as a matrix resin.

The present invention will be explained in detail below.

First, the condensed polycyclic aromatic resin used as the matrix resin in the FRP pipe of the present invention and its production will be explained.

The raw material for this resin is a condensed polycyclic aromatic compound or a mixture thereof with a seven-herb aromatic compound.

Examples of fused polycyclic aromatic compounds include fused polycyclic hydrocarbons such as naphthalene, acenaphthene, phenanthrene, anthracene, pyrene, chrysene, naphthacene, fluoranthene, perylene, bicene and their alkyl derivatives, various benzopyrenes, and various benzoperylenes; Examples include hydroxy-substituted derivatives such as naphthol, and mixtures of two or more of these can also be used. Examples of monocyclic aromatic compounds that can be used as raw materials include phenols such as phenol, alkylphenol, and resorcinol, and monocyclic aromatic compounds such as diphenyl, diphenyl ether, and alkylbenzene. can do.

Aromatic compounds having a polynuclear structure in which two or more aromatic compounds as described above are connected by a methylene group, a phenylene group, a xylylene group, etc. can also be used as the raw material. Further, coal-based or petroleum-based heavy oils and pitches containing the above-mentioned aromatic compounds as main components can also be used as raw materials.

A preferred raw material is one containing naphthalene as the fused polycyclic aromatic compound. A particularly preferred raw material is naphthalene alone or a mixture thereof with phenol.

When a monocyclic aromatic compound such as phenol is used as a raw material, hexamine (hexamethylenetetramine) or other suitable curing agent such as phenolic resin, fatty acid, or epoxy resin may be added during curing. .

The crosslinking agent used in the production of the resin used in the present invention is an aromatic compound having at least two hydroxymethyl or halomethyl groups; examples of such compounds include benzene, xylene, naphthalene, anthracene,
Poly(
hydroxymethyl) or poly(halomethyl)ifa
Examples include derivatives. Particularly preferred crosslinking agents are dihydroxymethylbenzene (xylene glycol), dihydroxymethylxylene, trihydroxymethylbenzene,
Dihydroxymethylnaphthalene and the like.

The above raw material and crosslinking agent are reacted in the presence of an acid catalyst, but in the production of the resin used in the present invention, an acid catalyst that is reactive with at least one of the raw material or the crosslinking agent or a water-insoluble acid is used. Use a catalyst.

Examples of reactive acid catalysts include organic aromatic sulfonic acids that easily react with the hydroxymethyl group or halomethyl group of the crosslinking agent, or organic aromatic acids that have a hydroxymethyl group, halomethyl group, or formyl group that reacts with the raw material aromatic compound. Mention may be made of the group sulfonic acids.

Acid catalysts that easily react with the hydroxymethyl group or halomethyl group of the crosslinking agent include organic sulfonic acids having a condensed polycyclic aromatic nucleus (such as a naphthalene nucleus) or a phenol nucleus, or carboxyl groups, amino groups, epoxy groups, and unsaturated Examples include organic aromatic sulfonic acids having hydrocarbon groups and the like.

Among these, particularly preferred are fused polycyclic aromatic sulfonic acids and phenolsulfonic acids, specifically naphthalenesulfonic acids, alkylnaphthalenesulfonic acids, acenaphthenesulfonic acids, anthracenesulfonic acids, phenolsulfonic acids, and naphtholsulfonic acids. Acids etc.

On the other hand, examples of organic sulfonic acids having a hydroxymethyl group, halomethyl group, or formyl group that react with raw material aromatic compounds include hydroxymethylbenzenesulfonic acid, hydroxymethylnaphthalenesulfonic acid, dihydroxymethylnaphthalenesulfonic acid, chloromethylbenzenesulfonic acid, Examples include chloromethylnaphthalenesulfonic acid, formylbenzenesulfonic acid, formylnaphthalenesulfonic acid, and the like.

Examples of water-insoluble acid catalysts include polystyrene sulfonic acid resin obtained by sulfonating a styrene polymer cross-linked with divinylbenzene, phenol sulfonic acid, naphthalene sulfonic acid, etc., with aldehyde or at least two hydroxymethyl groups or halomethyl groups. A phenol sulfonic acid resin condensed with a crosslinking agent consisting of an aromatic compound,
Alternatively, sulfonated products of condensed polycyclic polynuclear aromatic resins can be mentioned. The sulfonated product of the condensed polycyclic polynuclear aromatic resin can be easily obtained by sulfonating the condensed polycyclic polynuclear aromatic resin with concentrated sulfuric acid, and then removing the water-soluble acid by washing with water or the like.

Furthermore, water-insoluble organic sulfonic acid compounds having a hydrophobic group such as dinonylnaphthalenesulfonic acid and didodecylbenzenesulfonic acid can also be used.

The amount of acid catalyst used varies depending on the reactivity of the raw material, reaction temperature, etc., but - for boat fishing, it is required to be 0.2% by weight or more based on the mixture of raw material and crosslinking agent, preferably 1 to 20% by weight.
Weight%. If the amount of acid catalyst used is less than 0.2% by weight, the condensation reaction will not proceed sufficiently and the resulting resin will not exhibit sufficient thermosetting properties.

Further, if the amount is 20% by weight or more, the reaction rate becomes too high and reaction control becomes difficult, and the resin produced becomes non-uniform, which is not preferable.

The blending ratio of the crosslinking agent and the raw material to be crosslinked (raw material + acid catalyst) is
A molar ratio of 0.7 to 6 is preferable; if it is 0.7 or less, the resin produced will not exhibit thermosetting properties, and if it is 6 or more, the crosslinking agent will be excessive, and the reaction will tend to be suppressed, A more preferred range is a molar ratio of 1 to 3, which results in a somewhat heterogeneous product.

When the raw material, crosslinking agent, and acid catalyst are mixed in a predetermined ratio and subjected to an addition condensation reaction, if the acid catalyst is a reactive sulfonic acid, the catalyst reacts with the raw material or the crosslinking agent during the reaction. , is immobilized in the skeleton of the produced fat-attached intermediate condensate, and even if the catalyst used is water-soluble, it becomes substantially insoluble in water. Further, even when a water-insoluble catalyst is used, the acid catalyst contained in the resin product does not dissolve in water, so problems such as fogging and corrosion of the molding die can be avoided.

In contrast, in the production of conventional C0PNA resin, common organic sulfonic acids such as methanesulfonic acid and p-toluenesulfonic acid are used as acid catalysts, but these are not water-insoluble and are Since it has no reactivity with the crosslinking agent, the acid catalyst contained in the matrix resin is eluted into the condensation water, causing the above-mentioned problem.

The reaction temperature is about 50-200°C, preferably 80-180°C.
The reaction pressure at 0 °C is usually normal pressure or slightly elevated pressure, but in order to remove condensed water produced as a result of the reaction from the reaction system and increase reaction efficiency, the reaction may be carried out under reduced pressure. can.

Although it is easy to carry out the reaction in a molten state, it can also be carried out using a suitable solvent or dispersion medium. Also,
When the reaction is carried out using a solvent or the like, even if unreacted water-soluble free acid remains, it is advantageous because it can be removed during solvent separation. Even in the case of melt polymerization, water-soluble free acids can be removed with a suitable solvent.

As the reaction progresses, the viscosity of the reactant increases and a thermosetting resin (B-stage resin) is obtained, but if this is further heated to advance the reaction, an insoluble and infusible cured product is produced. do. Therefore, in order to use it as a matrix resin for manufacturing FRP pipes, the temperature is lowered at the B stage to stop the reaction. The resin at this stage still has heat meltability and solvent solubility, and has a pour point of 150°C.
The following uncured intermediate wire hardware. The resin in this state is 1
By heating to 00 to 350°C, it easily becomes a thermoset.

The reinforcing fibers used in the FRP pipe of the present invention are generally glass fibers, but carbon fibers, aramid fibers, and any other inorganic or organic fibers that can be used in the production of FRP can also be used. Only one type of fiber may be used, or two or more types of fiber may be used in combination. The type and shape of the reinforcing fibers may be appropriately selected depending on the use and molding method of the FRP pipe.

The FRP pipe can be formed by various conventionally known methods.

When manufacturing FRP pipes used for high-pressure piping such as oil country tubular goods, it is preferable to use the filament winding method (FW method), which is highly effective in reinforcing fibers.The FW method uses resin-impregnated continuous fibers (roving ) is formed by wrapping it around a mandrel mold while applying tension. Usually, after wrapping, the resin is cured and the mandrel is pulled out to form a pipe.

The aromatic resin intermediate tank hardware used in the present invention is thermosetting, and can be easily thermoset by heating to 100 to 350°C. In addition, in the FW method, resin viscosity is important for smooth impregnation and scraping, but the intermediate tank hardware is heated to 40 to 100°C, and then γ-
By adding 30 to 70% by weight of a suitable solvent such as butyrolactone, nitrobenzene, dioxane, etc., the viscosity can be adjusted to a value suitable for impregnation. Therefore, the aromatic resin used in the present invention can be used as a matrix resin in molding by the FW method without any problem.

The FRP pipe of the present invention can also be formed by a tape winding method (also referred to as sheet wrapping or tape wrapping method) in which a prepreg sheet whose rovings are impregnated with resin in advance is wound around a mandrel. The subsequent processing is performed in the same way as the FW method.
An FRP tube exhibiting even higher strength can be obtained. There are two methods for producing prepreg sheets: a solvent method in which the matrix resin is dissolved in an organic solvent, the reinforcing fibers are impregnated, the solvent is removed by heating, and the prepreg is obtained; Although there is a solvent-free method in which the FRP pipe is impregnated with water, either method can be adopted in forming the FRP pipe of the present invention.

A bag molding (autoclave molding) method in which sheet-like or mat-like prepreg is placed in a mold and molded under heat and pressure can also be adopted in the production of thick-walled vibrators.

For piping that does not require much strength, the FRP pipe of the present invention can be made by kneading short fibers such as chilibut strands with the intermediate ring metal material of the aromatic resin, and then using a conventional molding method such as extrusion or injection. It can also be molded.

In this case, the short fiber length is in the range of 0.01 to 50 m5,
The appropriate amount is in the range of 5 to 50%. Furthermore, customary additives such as fillers may be added; examples of suitable fillers are silica powder, mold release agents, silane coupling agents, etc. In addition, when a monocyclic compound such as phenol is used in combination with a condensed polycyclic aromatic compound as a raw material, an appropriate curing agent such as hexamethylenetetramine or polyepoxide may be added to accelerate curing. Good too.

The short fibers, resin, and optional additives can be kneaded in a dry state in a solid state, but it is preferable to knead the resin in a molten state using a roll mixer or the like, during or immediately after molding. Heat to an appropriate temperature to harden. This curing can be performed by heating the extrusion die in extrusion or by heating the molding vibrator immediately after extrusion, or by heating within the mold in the case of injection.

It is preferable that the FRP pipe obtained by the various methods described above is finally post-cured by heating it to a temperature of 170 to 230 ° C. for 8 to 12 hours.
This heat treatment further promotes crosslinking and significantly improves the heat resistance and mechanical properties of the FRP pipe.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Naphthalene (NAP) 10 as a fused polycyclic aromatic compound
0 parts by weight, paraxylene glycol (PX
G) 173 parts by weight CPXG/NAP-1-Ratio 1.
6) A mixture consisting of 8.3 parts by weight of β-naphthalene sulfonic acid, which is reactive with the hydroxymethyl group of the crosslinking agent as an acid catalyst, is heated to 110°C for 8 hours to cause an addition condensation reaction, and B A resin in a stage state was obtained.

This resin has a brown transparent appearance and a softening point of 60°C1.
The number average molecular weight was 920.

Chopped strands of glass fiber with a length of 2H are kneaded and blended into this resin in an amount of 20% by weight based on the weight of the resin,
It was extruded into a vibrator with an inner diameter of 100 m and a width of 4 m. The cylinder temperature of the extruder used was 100''C, and the screw speed was 30 rpm.

The molded FRP tube was heated in an oven to thermoset the matrix resin to obtain an FRP tube.

Test pieces were taken from the obtained FRP pipes and tensile tests were conducted at various temperatures to measure the tensile strength. The test results are shown in Figure 1. As can be seen from Figure 1, the second FRP tube had excellent heat resistance and maintained high strength even at high temperatures exceeding 200°C.

1. An FRP pipe was manufactured in the same manner as in Example 1, except that chopped carbon fiber strands (21 m in length) were used in place of the glass fibers used in Example 1.

The results of the tensile test of the obtained FRP tube are shown in FIG. 1. The overall tensile strength was higher than that of Example 1 due to the use of carbon fiber, which has a higher strength than glass fiber. The tendency of the strength to decrease with increasing temperature was similar to that of the FRP tube of Example 1, indicating excellent heat resistance.

Comparison ■ Commercially available polypropylene resin (softening point: 150°C) was kneaded with 20% by weight of the same chopped strands of glass fiber used in Example 1, and the same extrusion process as used in Example 1 was carried out. It was extruded using a machine at a cylinder temperature of 230° C. to form an FRP pipe of a similar shape.

The tensile strength of the obtained FRP pipe was measured in the same manner as in Example 1, and the results are also shown in FIG. As can be seen from Figure 1, the strength decreases significantly as the temperature rises, especially at 100
The strength decreases significantly at temperatures above °C, and the heat resistance is low.

■ Methylnaphthalene (MNA) is the main condensed polycyclic aromatic compound.
P) 100 parts by weight, 140 parts by weight of baraxylene glyco-/l as a crosslinking agent (PXG/MN/l P-[-
/l, ratio 1.3), a mixture consisting of 8.3 parts by weight of β-naphthalenesulfonic acid as an acid catalyst was heated to 110 °C for 5
By heating for a period of time, an addition condensation reaction was carried out to obtain a resin in a B-stage state. This resin had a brown transparent appearance, a softening point of 40° C., and a number average molecular weight of 500.

Add dioxane to this resin as a solvent at a rate of 50ff per resin.
The mixture added in an amount of i% is heated to 80°C, and the resulting resin liquid is sequentially impregnated with glass rovings made of continuous filaments. The method of 0 winding around the mandrel mold is 55° helical winding and 5° in-brane winding.
The inbrain-wound roving layer was made to account for 30% by weight of the total glass roving. After wrapping is completed, 1
The resin was thermally cured by heating at 00°C for 2 hours, followed by post-curing by heating at 180°C for 8 hours. after that,
The mandrel mold was demolded to obtain an FRP pipe with an outer diameter of 86 mm.

When the glass fiber volume content of this FRP pipe was measured, it was approximately 50%.

Test pieces were taken from this FRP pipe, and the heat resistance was evaluated by measuring the tensile strength at various temperatures.

The results are shown in Figure 2. By post-curing the resin and reinforcing it with continuous fibers, the decrease in tensile strength due to temperature rise was much smaller than in Example 1, and the heat resistance was improved. It can be seen that there has been further improvement.

This product uses bisphenol A type epoxy resin (molecular weight 380) as a matrix resin and aromatic amine curing agent in a weight ratio of 10.
Using a mixture of 0/23 and impregnating it with glass roving made of continuous fibers in the same manner as in Example 3, the method for 0 winding was the same as in Example 3. After 0 winding, the resin was cured by heating at 160''C for 8 hours, and then the mandrel mold was removed to obtain an FRP tube with an outer diameter of 89 mm.

The results of the tensile strength of this FRP pipe are also shown in FIG.

As can be seen from Figure 2, the tensile strength at room temperature was in Example 3.
However, the tensile strength decreases significantly at high temperatures, with the tensile strength decreasing to about half of the normal temperature strength at 150°C and about 1/10 of the normal temperature strength at 200°C.
Poor heat resistance.

A sheet of continuous length glass fibers arranged parallel to each other in one direction was impregnated with the resin used in Example 3 using a solvent method (adding 50% by weight of dioxane), and the solvent was removed by heating. The glass fiber volume content is approximately 55% and the thickness is approximately 0.
．． 3. A prepreg of tna was prepared.

Next, this prepreg was preheated to 60°C and placed in a mandrel mold with an outer diameter of 76 mm, so that the fiber direction was ±551 helical layer and ±5' inplane layer with respect to the axial direction of the mandrel. Wrapped using a roller. A heat-shrinkable tape was wrapped around this, and the resin was cured by heating at about 180° C. for 8 hours, and then the mandrel mold was pulled out to obtain an FRP pipe with an outer diameter of 88 cm.

As can be seen from Figure 0, which also shows the test results of the tensile strength of the obtained FRP pipe in Figure 2, the FRP pipe manufactured by the tape winding method of this example is different from the FRP pipe manufactured by the FW method of Example 3. It exhibits higher strength than pipe, and its high temperature strength is also excellent.

(Effects of the Invention) As explained above, the FRP pipe of the present invention has high high-temperature strength and exhibits excellent heat resistance that can be used sufficiently up to temperatures of about 200 to 250°C. Matrix resin is a thermosetting resin that is cheaper than polyimide resin, which has traditionally been used as a heat-resistant resin, and has excellent moldability, so it can be easily applied to various molding methods including the FW method. can. Therefore, since the FRP pipe of the present invention is easy to manufacture, has excellent heat resistance and mechanical properties, and is relatively inexpensive, it is believed that it will greatly contribute to the expansion of the use of FRP pipes.

[Brief explanation of drawings]

FIGS. 1 and 2 are graphs showing the high temperature tensile strength of FRP pipes obtained in Examples and Comparative Examples.

Claims (1)

[Claims] (1) a raw material consisting of a fused polycyclic aromatic compound or a mixture of a fused polycyclic aromatic compound and a monocyclic aromatic compound;
A crosslinking agent consisting of an aromatic compound having at least two hydroxymethyl groups or halomethyl groups is combined with an organic sulfonic acid compound having reactivity with at least one of the raw materials or the crosslinking agent, or a water-insoluble organic sulfonic acid compound or A heat-resistant FRP pipe characterized in that a matrix resin is a crosslinked condensed polycyclic aromatic resin obtained by reacting a sulfonic acid group-containing polymer as a catalyst.