Method for Producing a Flame-Resistant Textile Article

Abstract

Method for making a cellulose-comprising, flame-resistant, textile article comprising multiple flame-retardant treatments. The method comprises: a. providing at least part of the textile article with a non-cellulose-reactive, phosphorous-containing, flame-retardant compound, and b. providing at least part of the textile article with a cellulose-reactive, phosphorous-containing, flame-retardant compound. The method is suitable for producing flame-resistant, textile articles such as flame-resistant garments. Said garments can be used to protect individuals from flames and/or heat.

Claims

1. A method for making a textile article flame-resistant, wherein the textile article comprises cellulose-containing fibres, the method comprising: a. providing at least part of the textile article with a non-cellulose-reactive, phosphorous-containing, flame-retardant compound, and b. providing at least part of the textile article with a cellulose-reactive, phosphorous-containing, flame-retardant compound, wherein the parts treated according to treatments a. and b. coincide at least partially.

2. The method of claim 1, wherein treatments a. and b. are provided on cellulose comprising fibres before they are combined to form the textile article.

3. The method of claim 1 wherein treatment a. is provided prior to treatment b.

4. The method of claim 1 wherein treatment a. comprises providing a regenerated cellulosic spun fibre with a non-cellulose-reactive, phosphorous-containing, flame-retardant particulate by adding said particulates during production of the fibre prior to spinning.

5. The method of claim 4 wherein treatment a. is performed prior to treatment b.

6. The method of claim 1, wherein treatment a. comprises the formation of a cross-linked network of a non-cellulose-reactive, phosphorous-containing compound around and/or throughout the molecular structure of the fibre.

7. The method of claim 6, wherein treatments a. and b. are performed on the textile article.

8. (canceled)

9. (canceled)

10. The method of claim 1, wherein the cellulose-reactive, phosphorous-containing, flame-retardant compound provided in treatment b. comprises N-methylol phosphonate, more preferably N-methylol dimethyl phosphonopropionamide.

11. The method of claim 1, wherein the cellulose-reactive, phosphorous-containing, flame-retardant compound is applied from a solution comprising less than 300 g/L of the compound, more preferably less than 100 g/L and even more preferably less than 50 g/L.

12. A method for making a flame-resistant, cellulose-containing fabric, the method comprising: a. providing cellulose-containing fibres provided with a non-cellulose-reactive, phosphorous-containing, flame-retardant compound; weaving the cellulose-containing fibres to produce a woven flame-retardant fabric; and b. treating the fabric with a cellulose-reactive, phosphorous-containing, flame-retardant compound.

13. The method of claim 12, wherein the fibres provided in a. comprise regenerated cellulose and the non-cellulose-reactive, phosphorous-containing, flame-retardant compound consists of particulates which are distributed throughout the fibres.

14.-15. (canceled)

16. Flame-resistant textile article obtainable by the method of claim 1.

17.-25. (canceled)

26. Garment comprising the flame-resistant textile article according to claim 16.

27. Use of a non-cellulose-reactive, phosphorous-containing, flame-retardant compound and a cellulose-reactive, phosphorous-containing, flame-retardant compound in the method of claim 1.

28. (canceled)

29. A flame-resistant textile article comprising phosphorous, the phosphorous being present both as chemically-bound phosphorous and as non-chemically-bound phosphorous.

30. The flame-resistant textile article according to claim 29 wherein 70-90 wt % of the phosphorous is present as non-chemically-bound phosphorous and 30-10 wt % of the phosphorous is present as chemically-bound phosphorous.

31. (canceled)

32. The flame-resistant textile article according to claim 29 wherein the textile-article is a fabric or a garment.

33. Flame-resistant fabric obtainable by the method of claim 12.

34. Garment comprising the flame resistant fabric according to claim 33.

35. Use of a non-cellulose-reactive, phosphorous-containing, flame-retardant compound and a cellulose-reactive, phosphorous-containing, flame-retardant compound in the method of claim 12.

Description

EXAMPLES

Example 1

[0051] A flame-resistant fabric was woven from a fibre blend comprising 64% Lenzing FRwhich is a Rayon fibre that has been made flame retardant by a non-cellulose-reactive treatment -, 24% aramid, 10% polyamide, 2% antistatic fibre to a twill construction at approximately 180 g/m.sup.2. The same type of yarns was used in both directions (warp and weft). Subsequently the fabric was printed with a 100% coverage standard camouflage pattern composed of 7 colours. After the fabric was printed, a cellulose-reactive, phosphorous-containing, flame-retardant compound was applied to the fabric. This compound was applied by impregnating the fabric with an aqueous solution comprising Pyrovatex CP LF, Knittex MLF NEW, Phosphoric acid 85% and Invadin PBN according to the concentrations as indicated in the top half of Table 1. After the flame-retardant treatment liquid had sufficiently penetrated the fabric, the fabric was squeezed at a predetermined squeezing rate, pre-dried, and heat-treated by curing on a tenter frame for 1 minute at 170 C. to help bind the phosphorus compound to cellulose molecules. Subsequently it was neutralized by soaking it in a 12 g/L sodium hydroxide solution at 60 C. for 2 minutes and thoroughly rinsed using hot water. Thereafter, the samples received a standard fluorocarbon finish according to the bottom half of Table 1. This finish improves the water and oil repellent properties of the fabrics. The process of applying the finish consisted of soaking the samples in an aqueous solution comprising the ingredients according to Table 1 and rapid curing of the treated samples on a tenter frame for 1 minute at 170 C.

[0052] The resulting fabric was tested and the results of said tests are presented in Table 2. All washes referred to in Table 2 are performed using ISO 6330 using detergent 6 from Annex N and tumble drying. If not specifically indicated, the fabric was not washed.

TABLE-US-00001 TABLE 1 Flame-retardant treatment. Comparative example 1 Recipe 1 Recipe 2 Recipe 3 Process step 1: Cellulose-reactive flame-retardant treatment Pyrovatex 300 100 50 CP LF, g/L Knittex MLF 50 20 10 NEW, mL/L Phosphoric 20 20 20 acid 85%, g/L Invadin 5 5 5 PBN, ml/L Process step 2: Fluorocarbon finish Invadin PBN, 20 20 20 20 ml/L Nuva 2110 130 130 130 130 liq, g/L Perapret 10 10 10 10 Additive PEP, g/L Acetic acid 0.5 0.5 0.5 0.5 80%, g/L

[0053] Comparative example 1 was produced by the same procedure as the other samples except that no cellulose-reactive flame-retardant treatments was applied.

TABLE-US-00002 TABLE 2 Flame protection and physical properties. Comparative Rec- Rec- Rec- Test method example 1 ipe 1 ipe 2 ipe 3 After-flame ISO 15025 B, 3 0 0 0 0 0 0 0 time warp 4 seconds weft, sec flame exposure After-flame ISO 15025 B, 2 0 0 0 0 0 0 0 time warp 4 seconds weft, sec flame exposure (washed 5) Phosphorous 1.8 2.9 2.3 2.1 content (wt %) Phosphorous 1.8 2.7 2.3 2.1 content (wt %) (washed 5) Tensile ISO 13934-1 780 725 792 851 strength (warp), N Elongation at 18 20 20 19 break (warp), % Tensile strength ISO 13934-1 768 730 787 788 (warp), N (washed 5) Elongation at 17 18 17 17 break (warp), % (washed 5)

[0054] The flame-retardant treatment resulted in a considerable improvement in flame-resistant properties, particularly in after-flame time and phosphorous content. Both improvements were retained after 5 washings. Surprisingly the tensile strength and elongation at break were not compromised by the treatment but even marginally increased. Also after 5 washings the tensile strength and elongation at break were not compromised. The tensile strength even maintained its increment after 5 washings.

Example 2

[0055] The experiment of Example 1 was repeated on a fabric woven to a plain ripstop construction at approximately 210 g/m.sup.2. The yarns used to produce the fabric and the treatment received by the samples are identical to Example 1. Said fabric was tested for relevant properties. Results of these tests are presented in Table 3. All washes referred to in Table 3 are performed using ISO 6330 using detergent 6 from Annex N and tumble drying. If not specifically indicated, the fabric was not washed.

TABLE-US-00003 TABLE 3 Flame protection and physical properties. Comparative Rec- Rec- Rec- Test method example 2 ipe 1 ipe 2 ipe 3 After-flame ISO 15025 B, 3/0 0/0 0/0 0/0 time warp 4 seconds weft, sec flame exposure After-flame ISO 15025 B, 9/2 0/0 0/0 0/0 time warp 4 seconds weft, sec flame exposure (washed 5) Phosphorous 1.8 2.9 2.3 2.1 content (wt %) Phosphorous 1.8 2.4 2.2 2.0 content (wt %) (washed 5) LOI ISO 4598-2 27 28 Tensile ISO 13934-1 981 1017 1022 1045 strength (warp), N Elongation at 14 14 14 14 break, % Tensile ISO 13934-1 950 937 937 893 strength (warp), N (washed 5) Elongation at 15 15 14 14 break, % (washed 5)

[0056] Again, also for the heavier ripstop fabric, considerable improvements in flame-resistant properties were noted, particularly in after-flame time, phosphorous content and LOI. This improvement was retained even after 5 washings. Surprisingly the tensile strength and elongation at break were not compromised directly after the flame-retardant treatment as well as after 5 washed. The tensile strength even marginally increased.

Example 3

[0057] Flame-resistant fabric was woven to a twill construction at approximately 180 g/m.sup.2. The same type of yarns were used in both directions (warp and weft), for which the fibre blend comprised 64% Lenzing FR which is a Rayon fibre that has been made frame retardant by a non-cellulose-reactive treatment, 24% aramid, 10% polyamide, 2% antistatic fibre. The fabric was printed with a 100% coverage standard camouflage pattern composed of 7 colours. After the fabric was printed a cellulose-reactive, phosphorous-containing, flame-retardant compound was applied to the fabric according to the conditions given in Table 4: (1) in combination with a standard finish with the fluorocarbon (in one step) or (2) before a standard finish with the fluorocarbon had been carried out.

TABLE-US-00004 TABLE 4 Application of a flame-retardant treatment in combination with a fluorocarbon finish (recipe 1) or as a separate process step (recipe 2). Comparative example 3 Recipe 1 Recipe 2 Process step 1: Cellulose-reactive flame-retardant treatment Aflammit 50 50 KWB, g/L Knittex MLF 10 10 NEW, mL/L Phosphoric 20 20 acid 85%, g/L Invadin PBN, 20 20 ml/L Nuva 2110 130 liq, g/L Perapret 10 Additive PEP g/L Process step 2: Fluorocarbon finish Invadin PBN, 20 20 ml/L Nuva 2110 130 130 liq, g/L Perapret 10 10 Additive PEP, g/L Acetic acid 0.5 0.5 80%, g/L

[0058] Aflammit KWB was used as the cellulose-reactive, phosphorous-containing, flame-retardant compound. The fabric was impregnated with an aqueous solution comprising Aflammit KWB, Knittex MLF NEW, Phosphoric acid 85% and Invadin PBN in the concentrations as indicated in Table 4. After the flame-retardant treatment liquid had sufficiently penetrated the fabric, the fabric was squeezed at a predetermined squeezing rate, pre-dried, and heat-treated to bind the phosphorus compound to cellulose molecules.

[0059] Phosphoric acid was used as the catalysts that promotes esterification reaction of hydroxyl groups of cellulosic fibres. Knittex MLF NEW was used as cross-linking agent and to increase crease resistance of the fabric. Invadine PBN manufactured by Huntsman was used as penetrant in order to increase the ability of the phosphorous compound to penetrate the fabric.

[0060] Process step 1 (related to a flame-retardant treatment with or without fluorocarbon finish) consisted of the following steps: [0061] impregnation according to the steps of Table 4, [0062] curing on a tenter frame 1 minute at 170 C., [0063] neutralisation: 12 g/L sodium hydroxide at 60 C., minimum 2 minutes, [0064] rinsing in hot water, [0065] drying.

[0066] Process step 2 consisted of (related to a fluorocarbon finish alone) [0067] impregnation according to the steps of Table 4 [0068] rapid curing on a tenter frame 1 minute at 170 C.

[0069] As can be seen in Table 4, comparative example 3 was produced by the same procedure as the other samples except that no flame-retardant treatments and related process steps were used for this fabric.

[0070] Results of these tests are presented in Table 5. All washes referred to in Table 5 are performed using ISO 6330 using detergent 6 from Annex N and tumble drying. If not specifically indicated, the fabric was not washed.

TABLE-US-00005 TABLE 5 Flame protection and physical properties. Comparative Rec- Rec- Test method example 3 ipe 1 ipe 2 After-flame ISO 15025 B, 3 6 1 0 1 0 time warp 4 seconds weft, sec flame exposure After-flame ISO 15025 B, 2 3 1 1 1 1 time warp 4 seconds weft, sec flame exposure (washed 5) Water ISO 4920 5 5 5 repellence Water ISO 4920 4.5 4.5 4.5 repellence (washed 5) Oil repellence AATCC 118-1978 7 6 6 Oil repellence, AATCC 118-1978 6.5 5.5 6 (washed 5) Tear strength ISO 13937-2 49 46 49 42 45 44 warp weft, N Tear strength ISO 13937-2 38 35 42 38 38 40 warp weft, N, (washed 5)

[0071] As can be seen in Table 5, considerable improvement in flame-resistant properties particularly in after-flame time was noted when the flame-retardant treatment was combined with a fluorocarbon finish in one step or when these were carried out as separate steps. This improvement was retained even after 5 washings. The water and oil repellence along with physical properties were maintained at the same level for both initial and washed fabrics for both routes. The flame-retardant treatment hardly affected the tear strength. Surprisingly the decrease in tear strength due to washing was less for fabrics that did receive a flame-retardant treatment than that of fabrics that only received a fluorocarbon finish.

Example 4

[0072] Flame-resistant fabric was woven to a twill construction at approximately 180 g/m.sup.2. The same type of yarns were used in both directions (warp and weft), for which the fibre blend comprised 64% Lenzing FR which is a Rayon fibre that has been made frame retardant by a non-cellulose-reactive treatment, 24% aramid, 10% polyamide, 2% antistatic fibre and was for use in garments offering protection to brief exposure to substantial thermal fluxes. The fabric was printed with a 100% coverage standard camouflage pattern composed of 7 colours. After the fabric was printed a cellulose-reactive phosphorous-containing, flame-retardant compound was applied to the fabric according to the conditions given in Table 6. Also a standard finish with a fluorocarbon was carried out according to the conditions in Table 6.

TABLE-US-00006 TABLE 6 Application of a flame-retardant treatment. Comparative example 4 Recipe 1 Recipe 2 Process step: Cellulose-reactive flame-retardant treatment Aflammit 50 100 KWB, g/L Knittex MLF 10 20 NEW, mL/L Phosphoric 20 20 acid 85%, g/L Invadin PBN, 5 5 ml/L Process step: Fluorocarbon finish Invadin PBN, 20 20 20 ml/L Nuva 2110 130 130 130 liq, g/L Perapret 10 10 10 Additive PEP, g/L Acetic acid 0.5 0.5 0.5 80%, g/L

[0073] The process steps related to the flame-retardant treatment were as following: [0074] Impregnation (Table 6) [0075] Curing on a tenter frame 1 minute at 170 C. [0076] Neutralisation: 12 g/L sodium hydroxide at 60 C., minimum 2 minutes [0077] Rinsing in hot water [0078] Drying

[0079] Process step related to a fluorocarbon finish consisted of [0080] impregnation according to the steps of Table 6 [0081] rapid curing on a tenter frame 1 minute at 170 C.

[0082] The comparative example 4 was produced by the same procedure as the other samples except that no flame-retardant treatments and related process steps were used for this fabric.

[0083] The fabrics were subjected to storage and washing before being tested for after-flame properties. The washing conditions were according to ISO 6330 using detergent 6 from Annex N, a 40 C. program and tumble drying. Results of these tests are showed in Table 7.

TABLE-US-00007 TABLE 7 Flame protection after applying flame-retardant treatment as given in Table 6. Comparative Test method example 4 Recipe 1 Recipe 2 After-flame ISO 15025 A, time warp 3 seconds weft, sec flame exposure Not stored; 5 0 0 0 0 0 unwashed After 6 months 2 0 storage; unwashed Not stored; 0 7 2 0 0 0 washed 5 After 6 months 0 0 storage; washed 5 After 6 months 1 1 0 0 storage; washed 25 After 6 months 0 0 0 1 storage; washed 50 After-flame ISO 15025 B, time warp 3 seconds weft, sec flame exposure Not stored; 6 7 0 1 0 0 unwashed After 6 months 0 0 storage; unwashed Not stored; 5 4 0 1 3 0 washed 5 After 6 months 4 3 storage; washed 5 After 6 months 3 5 0 1 storage; washed 25 After 6 months 6 6 3 2 storage; washed 50 After-flame ISO 15025 A, time warp 4 seconds weft, sec flame exposure Not stored; 2 3 0 0 0 0 unwashed After 6 months 1 0 storage; unwashed After 12 months 2 0 storage, unwashed Not stored; 5 4 0 0 0 1 washed 5 After 6 months 0 0 storage; washed 5 After 12 months 0 0 storage; washed 5 After 6 months 4 1 0 1 storage; washed 25 After 6 months 1 1 1 0 storage; washed 50 After-flame ISO 15025 B, time warp 4 seconds weft, sec flame exposure Not stored; 3 2 0 0 0 0 unwashed After 6 months 0 0 storage; unwashed After 12 months 0 0 storage; unwashed Not stored; 4 3 0 0 0 0 washed 5 After 6 months 0 0 storage; washed 5 After 12 months 0 0 storage; washed 5 After 6 months 3 6 0 0 storage; washed 25 After 6 months 7 6 1 1 storage: washed 50

TABLE-US-00008 TABLE 8 LOI and Phosphorous/Nitrogen content after applying flame-retardant treatment as given in Table 6. Comparative example 4 Recipe 1 Recipe 2 LOI ISO 4598-2 Not stored; 26 27 unwashed Phosphorous content (wt %) P/N Not stored; P 1.7 P 1.9 P 2.2 unwashed After 6 months P 2.2/N 4.3 storage; unwashed After 12 months P 2.0/N 4.0 storage; unwashed After 6 months P 2.2/N 4.3 storage; washed 1 Not stored; P 1.9 P 1.9 P 2.2 washed 5 After 6 months P 2.1/N 4.3 storage; washed 5 After 6 months P 2.1/N 4.3 storage; washed 25 After 6 months P 2.1/N 4.3 storage; washed 50

TABLE-US-00009 TABLE 9 Physical properties after applying flame- retardant treatment as given in Table 6. Compar- ative Rec- Rec- Test method example ipe 1 ipe 2 Weight, g/m.sup.2 ISO 3801:1977 180 178 183 Water ISO 4920 5 5 5 repellency after washing 5 4.5 4.5 4.5 ISO 6330 6N, tumble dried Oil repellency AATCC 6.5 6.5 6.5 118-1978 after washing 5 7.5 7.5 7.5 ISO 6330 6N, tumble dried Abrasion ISO 12947 Part 2, 75,000 75,000 75,000 resistance, two threads rubs broken @ 12 kPa Air permeability, ISO 9237 434 434 457 L/m.sup.2/s Tensile ISO 13934-1 890 680 840 680 860 670 strength, N Elongation 9 16 9 16 9 16 at break, % Tear ISO 13937-2 45 43 46 42 47 44 strength, N

[0084] As can be seen from Tables 7-9, considerable improvement in flame-resistant properties, particularly in after-flame time, phosphorous content and LOI were noted. This improvement was retained even after 5 washings. Furthermore the improvement was retained after 6 or 12 months storage even after washing the stored product. The physical properties are maintained at the same level for both initial and washed fabrics, while the fabric weight and air permeability remained unaffected, does maintaining excellent comfort properties.

Example 5

[0085] Flame-resistant fabric was woven to a plain ripstop construction at approximately 190 g/m.sup.2. The same type of yarns were used in both directions (warp and weft), for which the fibre blend comprised 64% Lenzing FR which is a Rayon fibre that has been made frame retardant by a non-cellulose-reactive treatment, 24% aramid, 10% polyamide, 2% antistatic fibre and was for use in garments offering protection to brief exposure to substantial thermal fluxes. The fabric was printed with a 100% coverage standard camouflage pattern composed of 7 colours. After the fabric was printed a cellulose-reactive phosphorous-containing, flame-retardant compound was applied to the fabric according to the conditions given in Table 6 of Example 4. Further process steps are also as in Example 4. Thereafter, a standard finish with a fluorocarbon was carried out as in Example 4. The resulting fabric was tested and the results of said tests are presented in Tables 10-13. The washing conditions referred to in any of these tables were according to ISO 6330 using detergent 6 from Annex N, a 40 C. program and tumble drying

[0086] The comparative example 5 was produced by the same procedure as the other samples except that no flame-retardant treatments and related process steps were used for this fabric.

TABLE-US-00010 TABLE 10 Flame protection after applying flame-retardant treatment as given in Table 6. Compar- ative Rec- Rec- Test method example 5 ipe 1 ipe 2 After-flame ISO 15025 A, time warp 3 seconds weft, sec flame exposure Not stored; 5 0 0 0 0 0 unwashed Not stored; 0 7 2 0 0 0 washed 5 After 6 months 1 1 1 1 storage; washed 25 After 6 months 0 0 1 0 storage; washed 50 After-flame ISO 15025 B, time warp 3 seconds weft, sec flame exposure Not stored; 6 7 0 1 0 0 unwashed After 6 months 0 0 storage; unwashed Not stored; 5 4 0 1 3 0 washed 5 After 6 months 4 3 storage; Washed 5 After 6 months 3 5 0 1 storage; Washed 25 After 6 months 6 6 3 2 storage; Washed 50 After-flame ISO 15025 A, time warp 4 seconds weft, sec flame exposure Not stored; 2 3 0 0 0 0 unwashed After 6 months 1 0 storage; unwashed After 12 months 0 0 storage; unwashed Not stored; 5 4 0 0 0 1 washed 5 After 6 months 0 0 storage; washed 5 After 12 months 0 0 storage; washed 5 After 6 months 4 1 0 1 storage; washed 25 After 6 months 1 1 1 0 storage; washed 50 After-flame ISO 15025 B, time warp 4 seconds weft, sec flame exposure Not stored; 3 2 0 0 0 0 unwashed After 6 months 0 0 storage; unwashed After 12 months 0 0 storage; unwashed Not stored; 4 3 0 0 0 0 washed 5 After 6 months 0 0 storage; washed 5 After 12 months 0 0 storage; washed 5 After 6 months 3 6 0 0 storage; washed 25 After 6 months 7 6 1 1 storage; washed 50

TABLE-US-00011 TABLE 11 LOI and phosphorous/nitrogen content after applying flame-retardant treatment as given in Table 6. Compar- ative Rec- Rec- Test method example 5 ipe 1 ipe 2 LOI ISO 4598-2 Not stored, 27 28 unwashed Phosphorous content P/N (%) Not stored; P 1.7 P 1.9 P 2.1 unwashed After 12 months P 2.0/N 4.5 storage; unwashed Not stored; P 1.7 P 1.9 P 2.1 washed 5 Not stored; P 1.7/N 3.8 P 2.1/N 4.0 washed 25 Not stored; P 1.7/N 3.7 P 2.1/N 4.0 washed 50

TABLE-US-00012 TABLE 12 Physical properties after applying flame-retardant treatment as given in Table 6. Compar- ative Rec- Rec- Test method example 5 ipe 1 ipe 2 Weight, g/m.sup.2 ISO 3801:1977 191 191 193 Dimensional stability ISO 5077 2.5 1.5 2.0 2.0 2.0 2 after washing 5 ISO 6330 6N, tumble dried), % Water Repellency ISO 4920 5 5 5 after washing 5 ISO 4.5 4.0 4.5 6330 6N, tumble dried Oil repellency AATCC 118-1978 5.5 6.5 6.5 after washing 5 ISO 6 6.5 7.5 6330 6N, tumble dried Abrasion resistance, ISO 12947 Part 2, 75,000 75,000 83,333 rubs two threads broken @ 12 kPa Airpermeability, L/m.sup.2/s ISO 9237 381 364 373 Tensile strength, N ISO 13934-1 1400 1100 1400 1100 1400 1100 Elongation at break, % 14 16 15 16 14 16 Tear strength, N ISO 13937-2 92 85 84 84 85 81

[0087] As can be seen from Tables 10-12 considerable improvement in flame-resistant properties, particularly in after-flame time, phosphorous content, and LOI were noted. This improvement was retained even after 5 washings. Furthermore the improvement was retained after 6 or 12 months storage even after washing the stored product. The physical properties are maintained at the same level for both initial and washed fabrics, while the fabric weight and air permeability remained unaffected, thus maintaining excellent comfort properties.

[0088] Thus, the invention has been described by reference to certain examples discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art. In particular, the fibre blends and weights may be varied according to the intended use. Many modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention