Method of shaping a cured thermosetting resin

Abstract

The present invention relates to a method of shaping a cured thermosetting resin substrate, and more particularly to a method of shaping a cured thermosetting resin using electromagnetic radiation, said method comprises providing a cured thermosetting resin substrate; providing a confined temperature controlling environment; placing the cured thermosetting resin substrate in the confined temperature controlling environment; providing a source of electromagnetic radiation; irradiating the cured thermosetting resin substrate in the confined temperature controlling environment; and shaping the irradiated thermosetting resin substrate.

Claims

1. A method of shaping a cured thermosetting resin substrate, the method comprising the steps of: i. providing a cured thermosetting resin substrate; ii. providing a confined temperature controlling environment; iii. placing the cured thermosetting resin substrate in the confined temperature controlling environment; iv. providing a source of electromagnetic radiation; v. irradiating the cured thermosetting resin substrate in the confined temperature controlling environment; and vi. shaping the irradiated thermosetting resin substrate.

2. The method according to claim 1, wherein the confined temperature controlling environment is in the form of a gas, vapor, liquid, gel, or any combination thereof.

3. The method according to claim 2, wherein the confined temperature controlling environment is a liquid, and the liquid has a boiling point of 100 C. or greater.

4. The method according to claim 2, wherein the confined temperature controlling environment is a liquid, and is selected from the group consisting of ethylene glycol, butanol, toluene, decane, water, and any combinations thereof.

5. The method according to claim 2, wherein the confined temperature controlling environment is a liquid, and the liquid is heated to a temperature of 20 to 95 C. during irradiating.

6. The method according to claim 1, wherein at least 50% of the cured thermosetting resin substrate is immersed in the confined temperature controlling environment.

7. The method according to claim 1, wherein the cured thermosetting resin substrate is selected from the group consisting of a phenolic resin, polyester, acrylic resin, vinyl ester, polyurethane, an epoxy resin and a sheet-form molding material.

8. The method according to claim 7, wherein the cured thermosetting resin substrate is selected from the group consisting of phenolic resin, polyester and polyurethane.

9. The method according to claim 1, wherein the cured thermosetting resin substrate further comprises one or more fillers, wherein the one or more fillers are selected from the group consisting of clays, clay minerals, talc, graphite, calcium carbonate, gypsum, alumina, silicates, vermiculite, refractories, solid or hollow glass microspheres, fly ash, coal dust, wood flour, grain flour, nut shell flour, silica, finely chopped glass fibers, finely divided asbestos, chopped mineral fibers, finely chopped natural or synthetic fibers, ground plastics and resins in the form of powder or fibers, reclaimed waste plastics, reclaimed waste resins, pigments, powdered paint, carbon black, starches, and any combination thereof.

10. The method according to claim 1, wherein the cured thermosetting resin substrate comprises an open-cell structure.

11. The method according to claim 10, wherein at least 50% of available pore volume of the cured thermosetting resin substrate is filled with the confined temperature controlling environment.

12. The method according to claim 1, wherein the electromagnetic radiation is selected from the group consisting of microwave, radiofrequency, ultra-sound and infrared.

13. The method according to claim 12, wherein the electromagnetic radiation is microwave radiation, and the microwave radiation has a wavelength of 10 to 50 cm.

14. The method according to claim 12, wherein the electromagnetic radiation is microwave radiation, and the microwave radiation has a frequency of 25 GHz to 450 MHz.

15. The method according to claim 12, wherein the electromagnetic radiation is microwave radiation, and the microwave radiation transmits a power of 750 W to 100 kW.

16. The method according to claim 1, wherein the cured thermosetting resin is irradiated for less than 10 minutes.

17. The method according to claim 1, further comprising pre-treating the cured thermosetting resin substrate, wherein the pre-treating comprises cooling the cured thermosetting resin substrate.

18. The method according to claim 1, wherein the cured thermosetting resin substrate is subjected to a shaping pre-treatment, the shaping pre-treatment comprising changing a pre-shaped shape of the cured thermosetting resin substrate.

Description

EXAMPLES

Example 1

(1) Example 1 illustrates the effect of microwave radiation alone on a thermosetting resin substrate where no temperature controlling environment is present.

(2) In this example, a cured open-celled phenolic resin foam, produced in accordance with the disclosure above and available from Acell Holdings Limited, of dimensions 25 cm25 cm2 cm was placed in a domestic microwave providing a power of 800 W. The cured open-celled phenolic resin foam was irradiated for ten minutes. The surface temperature of the substrate was 90 C. as measured using a thermocouple, and the temperature of the water about 85 C. (for reference, similar temperatures were seen in all of the Examples).

(3) The resulting cured phenolic foam had darkened in colour. In addition, the foam block had further hardened, and therefore was more brittle. Accordingly, the irradiated phenolic foam could not be re-shaped.

Example 2

(4) Example 2 illustrates a method of the present invention.

(5) In this example, an identical sample of the cured open-celled phenolic resin as used in Example 1 was provided having the same dimensions. The cured open-celled phenolic foam was immersed in water, which acted as the temperature controlling environment. The cured open-celled phenolic foam was immersed and saturated in the water such that 80% of the available pore volume was filled with water.

(6) The saturated cured open-celled phenolic foam was then placed in a domestic microwave providing a power of 800 W and was irradiated for ten minutes.

(7) The resulting irradiated cured open-celled phenolic foam was removed from the microwave, the water allowed to drain, and was placed on a pipe for shapingall within about 30 seconds. The irradiated cured open-celled phenolic foam was shaped to the diameter of the pipe by hand. Upon cooling, and after 2 minutes, the new shape of the cured open-celled phenolic foam was fixed.

(8) This example clearly demonstrates that the presence of a temperature controlling environment is essential to the process, and that the shaping of a cured thermoset resin can be achieved by the method of the present invention.

Example 3

(9) Example 3 also illustrates a method of the present invention.

(10) In this example, an identical sample of the cured open-celled phenolic resin as used in Example 1 was provided having the same dimensions. The cured open-celled phenolic foam was immersed in water, which acted as temperature controlling environment. The cured open-celled phenolic foam was immersed in the water and saturated such that 80% of the available pore volume of the cured open-celled phenolic foam was filled with water.

(11) The saturated cured open-celled phenolic foam was then placed in a domestic microwave providing a power of 800 W and was irradiated for ten minutes.

(12) The resulting irradiated cured open-celled phenolic foam was removed from the microwave, the water allowed to drain, and was shapedall within about 30 seconds. For this example, the substrate was shaped by twisting the corners of the substrate by hand in opposite directions. The phenolic foam retained the new shape upon cooling.

(13) This example also illustrates that the method of the present invention enables the shaping of cured thermosetting resin substrates.

Example 4

(14) Example 4 illustrates the effect of heating a cured thermosetting resin in the presence of a temperature controlling environment but without the use of electromagnetic radiation.

(15) In this example, an identical sample of the cured open-celled phenolic resin as used in Example 1 was provided having the same dimensions The cured open-celled phenolic resin was placed in boiling water and maintained in this state for 10 minutes.

(16) The resulting cured open-celled phenolic foam was removed from the boiling water, the water allowed to drain, and shaping was attemptedall within about 30 seconds. However, the cured open-celled phenolic foam could not be shaped.

(17) This demonstrates that the effect of shaping a cured thermosetting resin cannot be attributed to the application of heat alone, nor to the presence of the temperature controlling environment alone, but that the present invention requires the use of electromagnetic radiation.

Example 5

(18) This example further illustrates the method of the present invention, even where a thermosetting resin substrate has already been previously shaped.

(19) In this example, the shaped product from Example 2 was used.

(20) The shaped product from Example 2 was immersed in water, which acted as the temperature controlling environment. The shaped product was immersed and saturated in the water such that 80% of the available pore volume was filled with water.

(21) The saturated shaped product was then placed in a domestic microwave providing a power of 800 W and was irradiated for ten minutes.

(22) The resulting irradiated shaped product was removed from the microwave, the water allowed to drain, and was placed on a pipe for re-shaping in the opposite directionall within about 30 seconds. The shaped product was re-shaped by hand to the diameter of the pipe. Upon cooling, and after 2 minutes, the new re-shape of the product from Example 2 was fixed.

(23) This example clearly demonstrates that re-shaping of cured thermosetting resin substrates is possible, even where the substrate has already been shaped using a method in accordance with the present invention.

Example 6

(24) Example 6 demonstrates the traditional effect of microwave radiation on a cured SMC resin substrate.

(25) In this example, the process of Example 1 was filed except a cured sample of sheet moulding compound (SMC) known as Menzolit SMC 0650 (polyester) was used. The dimensions of the cured sample were approximately 25 cm25 cm2 mm. The cured sample was placed in a domestic microwave providing a power of 800 W. The cured sample was irradiated for ten minutes.

(26) After irradiating, the sample was placed on a pipe for shaping but could not be shaped.

Example 7

(27) Example 7 illustrates the method of the present invention as applied to cured SMC resins.

(28) The cured SMC sample was immersed in water, which acted as the temperature controlling environment. The immersed cured SMC resin sample was then placed in a domestic microwave providing a power of 800 W and was irradiated for ten minutes.

(29) The resulting irradiated cured SMC resin sample was removed from the microwave and shaped on a pipe within 30 seconds of completion of irradiation. The cured SMC resin sample was shaped to the diameter of the pipe by hand. The cured SMC sample retained the new shape upon cooling.

(30) This example demonstrates that the process of the present invention can be applied generally to cured thermosetting resin substrates.

Example 8

(31) Example 8 repeated the process of Example 3, except using a cured SMC (polyester) resin.

(32) In this example, an identical sample of the cured SMC resin used in Example 6 was provided having the same dimensions, and was processed in accordance with the method of Example 3.

(33) The resulting cured irradiated SMC resin sample was removed from the microwave and was shaped within 30 seconds of completion of the irradiation by twisting the corners of the irradiated cured SMC resin by hand in opposite directions. The SMC retained the new shape upon cooling.

Example 9

(34) Example 9 repeated the process of Example 4, except using a cured SMC (polyester) resin.

(35) In this example, an identical sample of the cured SMC resin used in Example 6 was provided having the same dimensions, and was processed in accordance with the method of Example 4.

(36) The resulting cured SMC resin was removed from the boiling water and shaping was attemptedall within about 30 seconds. However, the cured SMC resin could not be shaped.

(37) This demonstrates that the effect of shaping a cured thermosetting resin cannot be attributed to the application of heat alone, nor to the presence of the temperature controlling environment alone, but that the present invention requires the use of electromagnetic radiation, even where different thermosetting resins are used.

Example 10

(38) Example 10 repeated the process of Example 5, except using a cured SMC (polyester) resin.

(39) In this example, the shaped product of Example 7 was used, and was processed in accordance with the method of Example 5.

(40) The resulting shaped cured SMC resin sample was removed from the microwave and was placed on a pipe for re-shaping in the opposite directionall within about 30 seconds. The shaped product was re-shaped by hand to the diameter of the pipe. Upon cooling, and after 2 minutes, the new re-shape of the product from Example 7 was fixed.

(41) This example clearly demonstrates that re-shaping of cured polyester thermosetting resin substrates is possible, even where the cured polyester material has already been shaped using a method in accordance with the present invention.

Example 11

(42) Example 11 illustrates the method of the present invention as applied to cured polyurethane resins.

(43) A cured polyurethane sheet containing a glass fibre mat was prepared using Axson PX 223/HT. The ratio of resin to fibre was 75:25.

(44) A cured 25 cm25 cm4 mm sample was prepared and was immersed in water, which acted as the temperature controlling environment. The immersed cured polyurethane resin sample was then placed in a domestic microwave providing a power of 800 W and was irradiated for ten minutes.

(45) The resulting irradiated cured polyurethane resin sample was removed from the microwave and shaped on a pipe within 30 seconds of completion of irradiation. The cured polyurethane resin sample was shaped to the diameter of the pipe by hand. The cured polyurethane sample retained the new shape upon cooling.

(46) This example demonstrates again demonstrates that the process of the present invention is generally applicable to cured thermosetting resin substrates.