MXPA99011627A

MXPA99011627A - Pipe with preform of fiber devanated with filamento and method to produce the mi

Info

Publication number: MXPA99011627A
Application number: MXPA/A/1999/011627A
Authority: MX
Inventors: Adam Sprague Paul; Clyde Kerecman Norman; Ringo Hoover William
Original assignee: Ao Smith Corporation
Priority date: 1998-12-11
Filing date: 1999-12-13
Publication date: 2000-11-01

Abstract

A tube having a fiber preform wound with filament and a tube production method is provided, first, the method involves the creation of a rigid preform by coating a fiberglass yarn with an epoxy or a resin polyester, filament winding, fiberglass yarn to form a structure has a side wall that defines openings through which it is able to penetrate a second resin, and cure the epoxy or polyester resin; a second resin, such as dicyclopentadiene, is cast centrifugally or molded by reaction injection around the preform, so that the second resin covers the preform, finally, the second resin is cured to form a tube; the manufacture of a reinforced tube of large diameter capable of withstanding high pressure

Description

PIPE WITH PREFORMA OF FIBER DEVANATED WITH FILAMENTO AND METHOD TO PRODUCE THE SAME FIELD OF THE INVENTION The invention relates to a reinforced tube, and particularly, to a tube reinforced with glass fiber.

BACKGROUND OF THE INVENTION It is a conventional way to reinforce a tube with fiberglass or other reinforcement material in order to strengthen the resulting tube. The stronger tubes can be used in a variety of applications in which the tubes can be subjected to high pressures. The strength of the tube can be increased by the addition of more reinforcing material to the tube, however, the additional reinforcing material typically increases the manufacturing cost of the tube and can result in undesirably thick tubular walls. A cost effective method of manufacturing a high-pressure reinforced tube with minimal use of reinforcement material would be beneficial.

BRIEF DESCRIPTION OF THE INVENTION Efforts to obtain a high-pressure reinforced tube have resulted in the use of glass cloth as reinforcement of the tube. However, glass cloth is more expensive than glass yarns and curls and knots in cloth filaments are less desirable than pre-stressed yarns. In addition, in a centrifugally cast large diameter tube, the fabric tends to collapse under its own weight while it is in the casting mold. It has been found that the strength obtained with the fabric reinforcements can be achieved with a more efficient use of the reinforcement, that is, the present invention provides a balance between the limiting quantities of the reinforcement material to reduce costs and volume, and provide enough reinforcement material to obtain the desired strength. As a result, the present invention can be used to economically manufacture the high pressure pipe useful, for example, in the petroleum industry. A further advantage of the present invention is the protection of the polymerization reaction of a higher resin from being poisoned by varnish in the fiber reinforcements. The invention provides a method of manufacturing a tube or a tube attachment. The method comprises the filament winding of a reinforcement coated with a first resin; hardening the first resin to form a preform; applying a second resin to the preform; and hardening the second resin to form the tube or tube fixation. The preferred reinforcement is glass fiber, and the second resin preferably is cast centrifugally around the preform, so that the second resin covers the preform. A more specific method according to the invention includes the steps of: (a) coating a fiberglass yarn with a first resin comprising an epoxy or a polyester; (b) filament winding the fiberglass yarn to form a structure having a side wall defining openings through which a second resin is capable of penetrating; (c) curing the first resin to form a rigid preform; (d) centrifugally casting the second resin around the preform so that the second resin covers the preform, the second resin includes a dicyclopentadiene; and (e) curing the second resin. The invention also provides an improved method of manufacturing a centrifugally cast tube. The improvement includes centrifugally casting a top resin around a preform made of a fiberglass reinforcement wound with filament that is coated with a first cured resin.

The invention also provides a tube that includes a rigid preform of a reinforcing material coated with a first resin; and a second resin that covers the preform. Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a tube section prepared according to the method of the invention. Figure 2 is a partial view of a preform made in accordance with the method of the invention and using a winding angle of about forty-five degrees (45 °) as measured from the axis of rotation of the mandrel. Figure 3 is a partial view similar to Figure 2, except that the preform is manufactured using a reeling angle greater than forty-five degrees (45 °) as measured from the axis of rotation of the mandrel. Before the embodiments of the invention are explained in detail, it should be understood that the invention is not limited in its application to the details of the composition or concentration of components, or to the steps or actions described in the following description or illustrated in drawings. The invention can have other modalities and can be practiced or carried out in various ways. Likewise, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be viewed as limiting.

DETAILED DESCRIPTION OF THE INVENTION The tubes manufactured according to the invention contain a preform made of a reinforcing material coated with a first resin. Figure 1 illustrates a section of the tube 10 having a preform 14 that is visible through, of a second cured resin. As shown in Fig. 2, the preform 14 can be prepared by a filament which wraps a reinforcement 18 at a desired unwinding angle in a mandrel 22 to form a structure around the mandrel. The mandrel 22 is preferably cylindrical. The filament winding is a conventional technique in which the fiber is coated in a resin bath and pulled by the force of a rotating mandrel that shapes the part. More specifically, as shown in FIG. 2, a layer of fiber threads 18 coated with resin is wound on the mandrel 22 in a shape that creates a pattern of openings or slits 26 where the fiber strands 18 do not cover the mandrel. 22. Because the preform 14 is wound with filament, which pretenses and aligns the fibers 18 in the desired direction, the amount of reinforcement required to obtain the same strength is minimized. A layer of bridging can provide adequate strength, however, if insufficient reinforcement is used or if the pattern of winding is very open, then the preform 14 can hinder the removal of the mandrel 22 without bending. A wrapping layer causes the reinforcement to be wound from one end of the mandrel to the other, leaving space between the wraps, then the reinforcement is wound from the far end of the mandrel back to the starting end, resulting in a cross pattern as shown in the figures. As the successive layers of the fiber strands are wound on the mandrel, the placement of the successive layers directly on top of the preceding layer extends the openings 26 or is emptied in a radial direction relative to the axis of rotation of the mandrel 16. to create a cylindrical screen or filter having openings that extend radially. Alternatively, the successive layers can be removed from the previous layer. After finishing the reeling process, the structure is removed from the mandrel. The result is a preform reinforced with fiberglass that is rigid enough to maintain its shape after removing the mandrel. The preform has several openings extending between the inner and outer surfaces of the preform through which a second resin is able to penetrate. Figures 2 and 3 illustrate the effect of a change in the angle of reeling in the size and shape of the slits 26 in the preform 14 wound with filament. The unwinding angle must be selected to equal the mechanical load. For example, for a longitudinal load, a smaller angle is generally better. As is known in the art, standard equations can be used to determine the unwinding angles. According to one of said equations, the circumferential tension is twice the longitudinal tension. In theory, the angle of unwinding can vary between a degree (1 o), as measured from the axis 30 of the mandrel 22, and eighty-nine degrees (89 °). However, in practice, the angle of winding preferably is between about forty degrees (40 °) and sixty degrees (60 °). About fifty-four degrees (54 ° +/- 5 °) are preferred. Figure 2 shows a preform 14 with a reeling angle of approximately forty-five degrees from the axis 30 and the resulting cross-sectional shape of the recesses 26 is almost a square. In Figure 3, the unwinding angle is greater than forty-five degrees and, as a result, the preform 14 shown in Figure 3 has diamond-shaped openings 26 having smaller axes 34 that are generally parallel to the mandrel axis 30. The openings are achieved through the use of an open knit winding. The fibers must be close enough so that the preform is rigid enough to be removed from the mandrel without bending and so that the end tube does not explode between the holes when under pressure. However, the fibers should not be placed so close that the preform is not porous to the top resin. The upper resin or the second upper resin must be able to penetrate the slits in the preform. Preferably, the slits or openings 26 of the preform 14 have a diameter greater than about 0.16 centimeters measured along the major axis, preferably, the openings are less than about 0.95 centimeters in diameter. With respect to the reinforcement material, the reinforcement includes filaments or fibers in the form of a strand, such as yarn or tow, which are sufficiently flexible to be wound with filament around the mandrel having a desired diameter. Any small fiber can be used, preferably in multifilament packages. Suitable reinforcing materials include various forms of glass (e.g., glass-e, glass-s, glass-a, or glass-c), silica, aromatic polyamide fiber, graphite / carbon fiber, nylon, etc. Fiberglass reinforcements are preferred, especially glass fiber yarns. Typically, when fiber yarns are wound with filament, the yarns are left individually or in a plurality of individual yarns to keep the yarns parallel to each other and uniformly tensioned (at about 0.453 kg of tension per yarn). Because the yarns are pretensioned, they do not bend or undulate before the filament winding as a garment fiber would. With respect to the resin used to wind the preform with filament, the resin can be any thermosetting or thermoplastic resin which is capable of being wound with filament and which is compatible with the upper resin. "Compatible" means that the resin does not contaminate the upper resin by preventing it from healing; Preferably, the resin used for filament winding adheres to the top resin. Representative thermosetting resins include vinyl ester, polyester, epoxy, furans, phenolic materials, dicyclopentadiene (DCPD), and mixtures thereof. Epoxy material, polyester or vinyl ester are most preferred; Polyester is the most preferred. Suitable thermoplastic materials may include butadienestyrene of acrylonitrile (ABS), acrylate, acrylic, polycarbonate (PC), polyester, polyethylene, fluoroplast, polyimide, nylon, polyphenylene oxide, polypropylene (PP), polystyrene (PS), polysulfone, polyvinyl (PVC), polyphenylene sulfide (PPS), polyetherimide (PEI), polyether ether ketone (PEEK), or mixtures thereof. Polypropylene, nylon, or polyethylene are the preferred thermoplastics. The thermoplastic can be in powder form and be heated to fuse to the filament prior to the reeling. Preferably, the first resin completely copper to the surface outside of the reinforcement in order to protect any polymerization reaction of a second resin from being poisoned by the varnish or other reinforcing additives. The first resin also holds the preform together. The resin content in the preform can be up to about 32% of the total resin weight and reinforcement. Any combination of the thermoplastic or thermosetting resin can be used as the first resin and as the second resin. The second resin is preferably of a composition different from that of the first resin. If two thermoplastic resins are used, then the upper resin preferably has a flow greater than the first resin used in the filament winding, so that the upper resin can flow through the openings in the preform. Preferably, the filament winding of the first resin is a thermosetting resin; more preferably an epoxy or a polyester. The top resin or the second resin that is applied to the preform must be able to flow in a mold, filling the voids in the mold and in the preform and penetrating and greatly covering the preform in this way. Suitable resins include heat-settable resins and thermoplastic resins. Representative thermosetting resins include vinyl ester, polyester, epoxy, furans, phenolics, urethanes, and norman-type monomers such as dicyclopentadiene (DCPD) or norbornene; the DCPD is preferred. Representative thermoplastic resins include acrylonitrile butadienestyrene (ABS), acrylate, acrylic, polycarbonate (PC), polyester, polyethylene, fluoroplast, polyimide, nylon, polyphenylene oxide, polypropylene (PP), polystyrene (PS9, polysulfone, polyvinyl chloride ( PVC), polyphenylene sulfide (PS9, polyetherimide (PEI), and polyether ether ketone (PEEK) .Mixes of said resins may also be suitable.Preferably, the second resin is a heat-settable resin, more preferably, a monomer of type norbornene, such as DCPD The polymerization catalyst can be any catalyst compatible with the top resin, so that it does not poison any desirable polymerization reaction.The suitable polymerization catalysts are known in the art.A complex ruthenium carbene catalyst is prefers within the DCPD systems because it is not poisoned by air and does not require an atmosphere of nitroge Such catalysts are described, for example, in U.S. Patent No. 5,312,940 to Grubbs, which is hereby incorporated by reference in its entirety. DCPD TELENE® resins, produced by B.F. Goodrich Company, they are also suitable. The top resin can be applied to the preform by a variety of methods. Representative methods include casting by centrifugation, casting, reaction injection molding (RIM), resin transfer molding (RTM), injection molding, etc. Each of said methods is well known in the art. RIM and casting by centrifugation are preferred. Generally, in the liquid RIM »the starting materials are mixed and injected into the mold cavity where they are cured to form a part. Casting by centrifugation is the most preferred method and casting by centrifugation of the plastic tube is described, for example, in U.S. Patent No. 3,266,370 to Woodson, which is fully incorporated herein by reference. The upper resin or the second resin is then hardened to form a tube or tube attachment. The first and second resins can be cured by cure or by cooling. Heat-settable resins are typically heat cured, and the thermoplastic resins can be cured by cooling below the melting point of the resin. Optionally, the glass cloth or other reinforcement material may be wrapped around the preform before the application or cure of the top resin. In this way, the preform acts as a mandrel in situ to support the glass cloth. Although the method of the present invention is suitable for lower diameter tubes, the method allows the manufacture of tubes of even longer diameter, for example, in the order of about 60.96 cm or 91.44 cm or longer. A rigid preform is preferred for the production of reinforced tubes having a diameter greater than about 30.48 cm or 35.56 cm.

EXAMPLE 1 The commercially available fiberglass yarn having a varnish compatible with the polyester was dipped in a bath of polyester resin and wound with filament from a mandrel with a diameter of about 5,588 cm. The winding was carried out at an angle of approximately 53.7 degrees relative to the axis of the mandrel, and an open spacing of about 0.3175 cm was left between the yarns. A single layer of fiberglass reinforcement was wound. The polyester is cured at a temperature of about 24 ° Celsius to form a rigid preform. The preform was removed from the mandrel and inserted into a diameter of 6,096 cm diameter casting tube mold by centrifugation. The liquid dicyclopentadiene resin was injected into the rotating mold, thereby covering the preform and forming a corrosion-resistant liner of pure resin in the tube. An infrared heat lamp was cured at around 38-49 ° C. The cured tube was removed from the mold and the ends trimmed. The resulting tube was tested by pressurizing with water by ASTM D1599 test procedure. A bursting pressure of 105.45 kg per square centimeter (kg / cm2) at 107 ° C was achieved.

EXAMPLE 2 A tube was prepared and tested as described in Example 1, except that the preform contained two layers of glass fiber instead of one. The two layers separated from each other by approximately 0.127 cm. The resulting tube did not fail even at pressures and temperatures of 126.54 kg / cm2 at 107 ° C, and 182.78 kg / cm2 at 24 ° C.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A method of manufacturing a tube or tube attachment, the method comprising: (a) filament winding a reinforcement coated with a first resin; (b) hardening the first resin to form a preform; (c) application of a second resin to the preform; and (d) hardening the second resin to form the tube or fix the tube.

2. The method according to claim 1, further characterized in that the coating is spun.

3. The method according to claim 1, further characterized in that the coating is spun from glass fiber.

4. The method according to claim 1, further characterized in that the first resin comprises a thermosetting resin or a thermoplastic resin.

5. The method according to claim 4, further characterized in that the first resin comprises an epoxy material, a polyester or vinyl ester.

6. The method according to claim 1, further characterized in that the first resin completely covers the outer surface of the reinforcement.

7. - The method according to claim 1, further characterized in that the preform defines slits through which the second resin can penetrate.

8. The method according to claim 1, further characterized in that the second resin comprises a thermosetting resin or a thermoplastic resin.

9. The method according to claim 1, further characterized in that the second resin comprises a thermosetting resin selected from the group consisting of vinyl ester, polyester, epoxy, furans, phenolics, urethanes, and monomers of the norbornene type.

10. The method according to claim 9, further characterized in that the second resin comprises dicyclopentadiene. 1.

The method according to claim 1, further characterized in that the second resin covers the preform.

12. The method according to claim 1, further characterized in that the second resin is applied to the preform by casting by centrifugation, casting, reaction injection molding, resin transfer molding, or injection molding of structural reaction.

13. The method according to claim 1, further characterized in that the second resin is applied by casting by centrifugation.

14. - The method according to claim 1, further characterized in that the second resin is applied by a different method to the filament winding.

15. The method according to claim 1, further characterized in that the second resin has a composition different from that of the first resin.

16. The method according to claim 1, further characterized in that the first resin and the second resin are hardened by curing or cooling.

17. The method according to claim 1, further characterized in that the tube has a diameter greater than about 30.48 cm.

18. The method according to claim 1, further characterized in that the preform defines slits through which the second resin can penetrate.

19. The method according to claim 18, further characterized in that the slits are at least about 0.423 cm in diameter.

20. The method according to claim 18, further characterized in that the slits are at least about 0.9525 cm in diameter.

21. A method of manufacturing a tube, the method comprising: (a) winding with filament a fiberglass reinforcement coated with a first resin; (b) curing the first resin to form a rigid preform; (c) centrifugally casting a second resin around the preform, so that the second resin covers the preform; and (d) curing the second resin to form the tube.

22. The method of manufacturing a tube, the method comprising: (a) coating a fiberglass yarn with a first resin comprising an epoxy or a polyester; (b) filament winding a fiberglass yarn to form a structure having a side wall, the side wall defining openings through which a second resin is capable of penetrating; (c) curing the first resin to form a rigid preform; (d) centrifugally casting the second resin around the preform, so that the second resin covers the preform, the second resin includes a dicyclopentadiene; and (e), cure the second resin.

23. An improved method of manufacturing a centrifugally cast tube, characterized in that the improvement comprises centrifugally casting an upper resin around a preform including the filament winding of the glass fiber reinforcement coated with a cured primary resin.

24. A tube comprising: a rigid preform of a reinforcing material coated with a first resin; and a second resin that covers the preform.