PHENOLIC MOULDING MATERIAL

Abstract

The present invention is concerned with moulding materials for use in the formation of composites and is particularly concerned with phenolic composites. More specifically, the present invention is concerned with phenolic resin materials which can be used without the need to add catalyst materials, and which therefore do not suffer as readily as known compositions from discolouration.

Claims

1. An uncured material for forming a phenolic resin sheet comprising: uncured phenolic resin; filler; a catalyst in an amount of less than 2 wt. % relative to the content of phenolic resin; and wherein the filler is present in a ratio of filler to uncured phenolic resin in an amount of 2.5:1 and greater, and further wherein the filler comprises a transition metal hydroxide and/or aluminium hydroxide in a ratio of metal hydroxide to uncured phenolic resin in an amount of 1:1.5 to 3:1.

2. An uncured material according to claim 1, wherein the catalyst is present in an amount of less than 1 wt. % relative to the content of the uncured phenolic resin.

3. An uncured material according to claim 2, wherein the catalyst is present in an amount of less than 0.5 wt. % relative to the content of the uncured phenolic resin.

4. An uncured material according to claim 3, wherein the catalyst is present in an amount of less than 0.2 wt. %

5. An uncured material according to claim 4, wherein the uncured material is substantially free of catalyst.

6. An uncured material according to claim 5, wherein the uncured material is free of catalyst.

7. An uncured material according to any preceding claim, wherein the filler is present in an amount of 3:1 and greater.

8. An uncured material according to claim 7, wherein the filler is present in an amount of 3.5:1 and greater.

9. An uncured material according to claim 8, wherein the filler is present in an amount of 5:1 and greater.

10. An uncured material according to any preceding claim, wherein the filler is present in an amount of 20:1 and less.

11. An uncured material according to any preceding claim, wherein the phenolic resin is a phenol-formaldehyde resin.

12. An uncured material according to any preceding claim, wherein the filler is a particulate solid which insoluble in the uncured material.

13. An uncured material according to any preceding claim, wherein the filler is inert to the rest of the uncured material.

14. An uncured material according to any preceding claim, wherein the filler is an inorganic material.

15. An uncured material according to any one of claims 1 to 14, wherein the filler is selected from one or more of clays, clay minerals, talc, vermiculite, metal oxides, refractories, solid or hollow glass microspheres, fly ash, coal dust, wood flour, grain flour, nut shell flour, silica, ground plastics and resins in the form of powder, powdered reclaimed waste plastics, powdered resins, pigments, and starches.

16. An uncured material according to any one of the preceding claims, wherein the transition metal or aluminium hydroxides are of formula M(OH).sub.3, wherein M is a metal.

17. An uncured material according to claim 16, wherein the metal M may be selected from one or more of scandium, vanadium, chromium, manganese, iron, cobalt and aluminium.

18. An uncured material according to any one of the preceding claims, wherein the metal hydroxide is aluminium hydroxide.

19. An uncured material according to any one of the preceding claims, wherein the ratio of metal hydroxide to uncured phenolic resin in an amount of 1:1.6 to 2.5:1.

20. An uncured material according to claim 19, wherein the in a ratio of metal hydroxide to uncured phenolic resin in an amount of 1:2 to 2:1.

21. An uncured material according to any one of claims 15 to 20, wherein the fillers do not substantially comprise silicates and/or carbonates of alkali metals.

22. An uncured material according to any one of claims 15 to 21, wherein the pigment is selected from one or more of metal oxides, powdered paint, rock powders and sand.

23. An uncured material according to any one of the preceding claims, wherein the material further comprises a viscosity controlling agent.

24. An uncured material according to claim 23, wherein the viscosity controlling agent is selected from butanol, chloroform, ethanol, water, acetonitrile, hexane, and isopropyl alcohol.

25. An uncured material according to any preceding claim, wherein the uncured material further comprises fibres.

26. An uncured material according to claim 25, wherein the fibres are woven or unwoven.

27. An uncured material according to any one of claims 25 to 26, wherein the fibres are in the form of a layer.

28. An uncured material according to claim 27, wherein the fibres are in the form of a mat or fabric.

29. An uncured material according to any one of claims 25 to 28, wherein the fibres are selected from one or more of mineral fibres (such as finely chopped glass fibre and finely divided asbestos), chopped fibres, finely chopped natural or synthetic fibres, and ground plastics and resins in the form of fibres.

30. An uncured material according to claim 29, wherein the fibres are selected from one or more of carbon fibres, glass fibres and aramid fibres.

31. An uncured material according to any one of claims 25 to 30, wherein the fibres are added to the uncured material in a ratio of resin to fibre of 6:1 to 1:3.

32. An uncured material according to claim 31, wherein the ratio is from 4:1 to 1:1.

33. A method of forming an uncured phenolic resin sheet comprising: i. providing an uncured material according to any one of claims 1 to 32; and ii. shaping the uncured material into a sheet.

34. A method according to claim 33, wherein the step of shaping involves the application of pressure.

35. A method of forming an uncured phenolic resin sheet comprising: i. providing an uncured material according to any one of claims 1 to 24; ii. providing fibres according to any one of claims 25 to 32 in the form of a layer; and iii. applying a layer of the uncured material to the fibres.

36. A method according to claim 35, wherein the step of applying the uncured material further comprises the application of pressure.

37. A uncured phenolic resin sheet produced by a method according to any one of claims 33 to 36.

38. A uncured phenoilic resin sheet produced from an uncured material according to any one of claims 1 to 32.

39. A method of forming a composite product comprising the steps of: i. providing an uncured phenolic resin material according to any one of claims 1 to 32, or an uncured phenolic resin sheet according to any one of claims 37 to 38; ii. providing a substrate; iii. applying a layer of the uncured phenolic resin material or uncured phenolic resin sheet onto a surface of the substrate; and iv. pressing the layer of the uncured phenolic resin material or uncured phenolic resin sheet to the substrate such that at least a portion of the of the uncured phenolic resin material or uncured phenolic resin sheet bonds to the substrate.

40. A method according to claim 39, further comprising the step of causing or allowing the uncured phenolic resin material or uncured phenolic resin sheet to at least partially set.

41. A method according to claim 40, wherein the step of causing or allowing the uncured phenolic resin material or uncured phenolic resin sheet to at least partially set comprises heating the uncured phenolic resin material or uncured phenolic resin sheet to a suitable temperature.

42. A method according to claim 41, wherein the uncured phenolic resin material or uncured phenolic resin sheet is heated to a temperature of at least 50° C.

43. A method according to claim 41 or 42, wherein the uncured phenolic resin material or uncured phenolic resin sheet is heated to a temperature between 100 and 200° C.

44. A method according any one of claims 39 to 43, wherein the uncured phenolic resin material or uncured phenolic resin sheet is heated for at least one minute.

45. A method according to any one of claims 39 to 44, wherein the substrate is an open-cell foam, and during the pressing step at least a portion of the uncured phenolic resin material or uncured phenolic resin sheet flows into the substrate.

46. A method according to claim 45, wherein the open-cell foam substrate is selected from a foamed phenolic resin or a foamed polyurethane resin.

47. A method according to claim 46, wherein the open-cell foam substrate is a foamed phenolic resin.

48. A method according to any one of claims 39 to 47, wherein the uncured phenolic resin material or uncured phenolic resin sheet is applied to substantially all of the open-cell foam substrate.

49. A method according to any one of claims 39 to 48, wherein the substrate is shaped before the step of pressing the layer of uncured phenolic resin material or uncured phenolic resin sheet to the substrate.

50. A method according to any one of claims 39 to 49, wherein a pressure of at least 400 Pa is applied during pressing.

51. A method according to claim 50, wherein a pressure of between 500 and 7,000 Pa is applied to the uncured phenolic resin material or uncured phenolic resin sheet.

52. A method according to any one of claims 39 to 51, wherein the open-cell foam substrate is a crushable material such that, during the application of pressure, the surface of the substrate is moulded.

53. A product formed by a method according to any one of claims 39 to 52.

54. A product comprising an open-cell foam substrate and a skin of phenolic resin bonded to a surface of the substrate, wherein the phenolic resin is as described in any one of claims 1 to 32.

55. Use of a phenolic resin paste for forming a coloured resin skin, wherein the phenolic resin is as described in any one of claims 1 to 32.

56. Use according to claim 55 wherein the resin skin is white, yellow, pink, red, orange, green, blue or purple.

Description

[0148] The present invention will now be described by way of the following examples, together with the accompany figures in which:

[0149] FIG. 1 is a general process for forming an uncured phenolic resin sheet in accordance with the present inventions.

EXAMPLES

[0150] The present examples illustrate the both the colour variation and strength of phenolic resins which can be produced in accordance with the present invention in comparison with SMC compounds of the prior art.

Example 1

[0151] A phenolic resin paste was formed according to the composition shown in Table 1 by use of a mechanical mixer until such time that the components appeared to be homogeneously combined.

TABLE-US-00001 TABLE 1 Weight (Kg) Wt. % Phenolic resin 1 28.29 Grey sand 1.6 45.26 Al(OH).sub.3 0.9 25.46 C.sub.36H.sub.70O.sub.4Zn 0.015 0.42 Black Iron oxide 0.02 0.57 Total 3.535 100

[0152] In addition, chops of glass fibers were added in a ratio of 2:1 resin to fibres, so as to mimic the amount of glass fibres in SMC.

[0153] Once formed the uncured resin material was rolled into a 3 mm thick sheet and allowed to rest overnight.

[0154] In order to produce a composite the uncured resin sheet was cut to produce a square 30 cm×30 cm, which was placed on an open-celled phenolic substrate (Acell foam sold by Acell Holdings Limited) of dimensions 30 cm×30 cm×3 cm.

[0155] The assembled materials were placed in a press and heated and pressed to cure the phenolic sheet.

[0156] The resulting composite panel was grey in colour.

Example 2

[0157] A phenolic resin paste was formed according to the composition shown in Table 2 by use of a mechanical mixer until such time that the components appeared to be homogeneously combined.

TABLE-US-00002 Weight (Kg) Wt % Phenolic resin 1 34.25 Marble powder 1.2 41.10 Al(OH).sub.3 0.6 20.55 C.sub.36H.sub.70O.sub.4Zn 0.01 0.34 TiO.sub.2 0.11 3.77 Total 2.92 100

[0158] In addition, chops of glass fibers were added in a ratio of 2:1 resin to fibres, so as to mimic the amount of glass fibres in SMC.

[0159] The process used to form the composite was identical to that used in Example 1.

[0160] The resulting composite panel was white in colour.

Example 3

[0161] A phenolic resin paste was formed according to the composition shown in Table 3 by use of a mechanical mixer until such time that the components appeared to be homogeneously combined.

TABLE-US-00003 TABLE 3 Weight (Kg) Wt % Phenolic resin 1 24.90 Grey sand 1.6 39.84 Al(OH).sub.3 1.2 29.88 C.sub.36H.sub.70O.sub.4Zn 0.022 0.55 Black Iron oxide 0.194 4.83 Total 3.535 100

[0162] In addition, chops of glass fibers were added in a ratio of 2:1 resin to fibres, so as to mimic the amount of glass fibres in SMC.

[0163] Further, 1 litre of water was added to the mixture during preparation as the viscosity of the mixture was higher than that in Examples 1 and 2. The water was added as a viscosity controlling agent.

[0164] The process used to form the composite was identical to that used in Example 1, with the exception was the water was allowed to evaporate from the sheet prior to processing so that its final viscosity (before processing) was similar to that of Examples 1 and 2.

[0165] The resulting composite panel was black in colour.

Comparative Example

[0166] For this example, instead of a phenolic material in accordance with the present invention, a commercial SMC was used. More specifically a 3 mm thick sheet of Menzolit® SMC 0650 was used.

[0167] The process used to form the composite was identical to that used in Example 1.

[0168] The resulting composite panel was then used in a test in comparison to those of Examples 1 to 3. More specifically, a brick was placed under the ends of each of the panels so that the panels were raised.

[0169] An 8 kg load was placed on each panel and left for a period of 10 minutes, after which time the amount of deflection in the panels was noted.

[0170] The results of the test were that the phenolic resin composites of the present invention showed less deflection than that produced using the SMC.