GB1602720A

GB1602720A - Fire retardant formulation

Info

Publication number: GB1602720A
Application number: GB3516477A
Authority: GB
Original assignee: Thacker D A
Current assignee: Thacker D A
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-11-18

Description

(54) FIRE RETARDANT FORMULATION (71) I, DEREK AUBREY THACKER, a British Subject, of Blue Seas, 47 Southdean Drive, Middleton, Bognor Regis, West Sussex, PO22 7TB, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to fire retardant formulations, and particularly those suitable for treating natural rather than synthetic products.

A large proportion of the structural components, furnishings and clothes that are in use now-a-days contain a high proportion of natural products which are readily susceptible to damage by fire. The response of such items to the application of heat is well known; flaming will usually occur at the site of the application of heat and even when the source of heat is removed flaming will often continue for some-time afterwards. Due to heat retention around the site of the flaming, charring will in general occur progressively away from this site accompanied by the evolution of smoke.

Many flame proofing and fire retardant formulations for treating such items have been tried in an attempt to reduce the items' susceptability to flaming, the flame spread and the char length. The choice of a suitable formulation has been made more difficult because of the common use of blends of natural and synthetic materials.

Thus whilst one particular formulation may be suitable for, e.g. a pure cotton dress, it might well be of little effect when the dress is made of a blend of, say, cotton and a polyester. Furthermore, a particular formulation may be good at preventing actual flaming, but may have little effect in reducing the char length.

Other considerations that must be borne in mind ure the formulations' own reaction to heat, i.e. whether any toxic fumes are involved, and the formulations' dermatitic reaction, i.e. it must not irritate the skin if it is to be used for treating clothes and soft furnishings. Also if the formulation is in the form of a solution or dispersion, it may be stable and not separate out.

Thus a need exists for a "balanced" flame proofing and fire retardant formulation, i.e. one which will have a beneficial effect on the fire characteristics of a broad range of materials, whilst at the same time fulfilling the above considerations.

In accordance with the present invention there is provided a flame-proofing and fire retardant composition comprising an aqueous solution of: (a) diammonium hydrogen phosphate (b) ammonium dihydrogen phosphate, and (c) ammonium sulphate.

The present invention also provides an anhydrous mixture which on dissolution in water yields a composition of the present invention.

Preferably the present composition also includes Chemflex 3, Natrio, sodium hypochlorite and sodium chloride.

Chemflex 3 is a trade name of a commercially-available product manufactured by Norkem Supplies of Kings Lynn, Norfolk, and Natrio is the trade name of a commercially-available product manufactured by Arnott Blenders, of Cheam, London.

Preferably, the ratio by weight of component (a) to component (c) is between 1:1.75 and 1:2.25, desirably about 1:2, whilst the ratio by weight of component (a) to component (b) is between 1:0.8 and 1:1.5, desirably about 1:1. When a hypochlorite salt is used, up to 0.02 ó is satisfactory with a weight ratio thereof to chloride salt, when present, of between 1:8 and 1:20.

Advantageously, a surface active agent, e.g. sodium lauryl sulphate, is present in an amount of up to 0.75% by weight, based on the weight of the composition. For natural material, it is preferred to include a binder, such as sodium carboxymethyl cellulose in an amount of up to 0.5% by weight. For synthetic material, an etching agent, e.g. sodium hydrogen sulphate is added in an amount of up to 2% by weight.

Desirably an additional ammonium salt, e.g. ammonium sulphamate or ammonium metaborate, is present in a total amount of up to 15% by weight.

It is preferred to manufacture the present composition as a concentrate ready for dilution by the user, and in this Case the following formulation has been found to possess a very good "balance" of properties: TABLE 1

wtPb wt Ó Substance grams/gallon Total solids total (a) diammonium hydrogen phosphate 508 1 21.71 (b) ammonium dihydrogen phosphate 636 > 2027 27.18 > 88.55 (c) ammonium sulphate 928 J 39.66 (d) Chemflex 3 200 200 8.55 8.55 (e) Natrio 36 36 1.53 1.53 (f) sodium hypochlorite & # 32 32 1.37 1.37 (g) sodium chloride Check Totals 2340 2340 100.00 100.00 An aqueous mixture of 1% by weight sodium hypochlorite and 16.5% by weight sodium chloride is commercially available, and this is the mixture referred to in Table 1 above.

For commercial reasons the present concentrate is prepared from industrial grade starting materials and due to impurities time must in general be allowed for the removal of scum and sediments. The following scheme has been used to produce the present concentrate in the form of a stable solution:: TABLE 2

Component Day added Action 1 (a) mix with preferably de-ionised water, raise to between 70 and 80"F, agitate 2 (b) mix, agitate, check for scum and/or sediment 3 (c) mix, agitate, leave to stand 4 - check for scum and/or sediment 5 (d) mix, agitate 6 (e) mix, agitate, check for scum and/or sediment 7 (f) & (g) mix, agitate, bring down to ambient temperature 7-11 - stand 12-13 - -- final scum and/or sediment check 14 - package for delivery To the completed concentrate, one or more additives can be added before final packaging and delivery depending on the particular field of application for the final formulation. Suitable additives which have been found to be compatible with the present composition are described in detail below.

A dilution of 1:3 v/v concentrate/water is generally satisfactory for most applications of the present formulation.

As mentioned previously, the formulation particularly described above has been found to have a very good "balance" of properties, and to be effective on items containing from 100% to about 20%, preferably 100% to 30% by weight of natural products, the remainder being synthetic products. If the amount of any one of the components is varied by more than 5%, it has been found that this "balance" is disturbed in some way so that the final formulation is of more limited usefulness.

A similar effect has been noted if the amount of more than one component is varied so that the total variation is greater than 5%.

The pH of the final solution also appears to be significant and whilst the abovedescribed formulation has a pH of 6.4, variations of pH outside a range of 6.0 to 6.8 appear to be undesirable, although between 5 and 8 can sometimes be acceptable.

If necessary the pH can be adjusted before packaging and delivery by using an appropriate acidic or alkaline solution.

The present formulation in its dilute form can be applied to the item to be protected by simple spray application, complete immersion, or vacuum impregnation of the finished product. Alternatively and preferably, the formulation can be added as a concentrate to one of the process streams of the manufacturing plant. Conventional free air drying or careful forced air drying can then be used to complete the treatment of the item.

A wide range of items can be treated with the present formulation, e.g. wallpaper, textiles, curtains, clothes, chair covers, upholstery, carpets, partitioning, ceiling and floor boards, wooden doors, wood panelling, wooden joists and beams, and in general any items containing at least about 20% by weight of natural products. Examples of such natural products are; wool, hair and all cellulose derivatives such as paper, cardboard, hardboard, chip-board, particle board, block board, insulation board, plaster board, veneers, timber, cotton, viscous rayon, jute, sisal, hessian, hemp, etc.

A further and interesting effect of the present formulation is in connection with urea-formaldehyde resins. It has been found that when, for example, a ureaformaldehyde coated chip-board has been treated with the formulation and is subjected to a source of heat e.g. a flame, intumescence occurs on the surface of the material which protects the surrounding and underlying material against charring and flame spread.

Foamed materials such as the polyurethane backing of carpets, also appears to be beneficially affected by the present formulation, possibly because of their moisture absorbing properties.

The "synthetic" products which do not appear to be significantly affected by the present formulation are those consisting of essentially non-absorbent polymeric fibres, such as polyamides e.g. nylon, polyacrylonitriles, polyesters, etc.

For specific applications the following additives may be used in the present formulation. Only small amounts need be employed, the actual amount depending, of course, on the particular material to be treated.

(i) ammonium uranium fluoride, UO2(NH4)2F5 where its use is allowed, this acts as a tracer so that the extent of treatment can be determined.

(ii) ammonium zirconyl carbonate, (NH4)3 ZrOH(COs)3 although toxic, this has good water proofing properties and so can be used externally e.g. on tents and outside woodwork.

(iii) ammoniacum (gum ammoniac) This is an emulsifying agent and prevents the leaching out of the other components. Particularly useful on heavy textiles.

(iv) sodium metasilicate, NaSiO2.

This, like (iii) is a fixative and can be used with moderately heavy textiles.

Due to its insolubility, however, isopropanol generally has to be added as an emulsifier.

(v) potassium monopersulphate.

This is a bactericide and fungicide which is advantageously used in the treatment of paper products e.g. wall-papers.

The following test results have been obtained using the present formulation: Tests Carried Out According to B.S. 476: Part 5: 1968, "The Ignitability Test for Materials 1. Introduction One specimen of untreated kitchen roll and three of treated kitchen roll have been subjected to the "Ignitability Test for Materials" detailed in B.S. 476: Part 5, 1968.

2. Material Sent for Test The material submitted was Specimen 1-Kitchen roll, untreated Specimen 2,3,4--Kitchen roll treated with the diluted solution at 1 ounce of solution, by spray, per sq. yd.

3. Observations & Results 3.1. Specimen I Ignites and flames. Had three specimens been tested, would have been designed "X", easily ignitable.

3.2. Specimens 2,3,4 No flaming occurred after the test flame was removed.

Designated "P"-not easily ignitable.

Surface Spread of Flame Test 1. Abstract A sample of wool carpet treated with the diluted solution has been tested and classified for surface spread of flame in accordance with B.S. 476: Part 7: 1971, Section 2. A Class 1 result was obtained.

2. Material Sent for Test This was a sample of Axminster woven wool carpet treated with the solution at 25/30 grm/sq. ft. loading applied by spray. The pile face of the carpet was exposed in all tests.

3. Test Procedure Six specimens were tested with the pile surface exposed to thermal radiation using the apparatus specified in the Standard.

4. Observations There was slight contribution to the pilot flame in most cases, with some flickering and flaming. Little flaming was observed after the pilot flame had been extinguished at 1 minute. Smoking was moderate.

The results for each specimen are given below.

5. Conclusion In accordance with the flame spread classification given in the Standard, the results show that the material had a Class 1 surface.

Results

Final Flame Spread Specimen Distance of Spread of No. Flame at 19 min., mm. distance, mm. Time min. sec.

1 60 80 10.00 2 65 65 1.00 3 75 150 1.00 4 60 60 1.00 5 70 70 1.35 6 75 75 1.00 Flame Spread Classification

Flame spread at 11 min. Final Flame Spread Tolerance for Tolerance for one specimen one specimen Classification Limit in sample. Limit in sample.

mm mm mm mm Class 1 165 25 165 25 Class 2 215 25 455 45 Class 3 265 25 710 75 Class 4 Exceeding Class 3 limits The flame spread on any specimen of the sample shall not exceed the limit assigned for the class with the proviso that for one specimen only in the sample the flame spread may exceed this -limit by the tolerance shown.

Ignitability Test for Materials 1. Introduction A sample of 2" thickness ceiling insulation board has been tested according to B.S.476: Part 5; 1968, the Ignitability Test for Materials. The material was designated "P" not easily ignitable.

2. Material Sent for Test This was a " thickness ceiling insulation board, treated with the diluted solution applied by spray.

Three specimens were tested, the decorative face being exposed.

3. Observations & Results There was no flaming with any specimen after removal of the test flame.

4. Conclusion: The material tested has been designed "P" i.e. not easily ignitable in the context of the Standard.

Test for Indication of Surface Spread of Flame 1. Introduction One specimen has been tested for indication of surface spread of flame according to B.S. 476: Part 7: 1971, Section 2.

2. Material Sent for Test The material sent for test was 1 piece of insulation board, 2 inch thickness, brush treated with the diluted solution.

Only one specimen was tested.

3. Observation & Results Slight contribution was observed with the pilot flame applied but there was only charring after 1 minute.

Surface spread of flame was recorded as 50 mm at 1 minute 30 seconds and 50 mm finally, indicating a Class 1 surface.

Determination of the Effects of a Small Source of Ignition on Textile Floor Coverings (Hot Metal Nut Method) 1. Introduction A sample of treated carpet has been tested according to the Method for determination of the effects of a small source of ignition on textile floor coverings (hot metal nut method), B.S. 4790: 1972 as amended by AMD 1847 of 31st October 1975.

2. Material Sent for Test The material submitted for test was a red Axminster carpet treated with the diluted solution with a retention rate equivalent to 14% by weight. Treatment was by spray.

3. Observations & Results The test results relate only to the behaviour of the test specimens after application of a small source of ignition; they shall not be used as a means of assessing how the product will contribute to an established fire.

The following results were obtained on three specimens tested.

Specimen 1-The specimen did not ignite.

The maximum radius of char on the pile face was 20 mm.

The maximum radius of char on the under surface was NIL mm.

Pungent smoke was evolved during the application of the nut.

Specimen 2-The specimen did not ignite.

The maximum radius of char on the pile face was 20 mm.

The maximum radius of char on the under surface was NIL mm.

Pungent smoke was evolved during the application of the nut.

Specimen 3-The specimen did not ignite.

The maximum radius of char on the pile face was 20 mm.

The maximum radius of char on the underside was NIL mm.

Pungent smoke was evolved during the application of the nut.

Material Test Report Untreated Chipboard 12 min. Flaming for 43 secs.

Blow lamp Char depth 4 mm. Flame to edge pattern 81 mm.

Chipboard coated with 12 min. Flame 7 sec. Char depth Ciba Geigy Urea 1.5 mm. Flame pattern Formaldehyde 'V' plus 73 mm.

the solution Expanded Polystyrene 10 sec. No flame. No damage.

tile coated Intumescent urea-formaldehyde and the solution Honeycomb Paper coated 5 sec. No damage. Intumescence urea-formaldehyde removable.

and the solution 10 sec. Very slight char 15 sec. Slight char. No surface break.

30 sec. 3 sec. flame. Self extinguishing.

Honeycombs Paper coated 10 sec. Veneer burnt but no and faced with untreated surface damage to paper veneer and no flaming after veneer burnt.

Honeycomb Paper coated with 12 min. No flame.

urea-formaldehyde and the Very slight damage to solution and faced with paper.

hessian treated with the solution Hessian treated with the 1+ min. Carbonisation to flame solution Horizontal pattern only. No flame.

Hessian treated with 10 sec. No flame, no spread.

the solution Vertical Hessian treated with the 1 min. No flame or spread.

solution Insulation board 1 min. No damage to board.

coated with urea- No flame.

formaldehyde and the solution Blockboard coated 30 sec. Maximum flame spread.

with urea-formaldehyde Burning.

only Blockboard coated with 30 sec. Intumescence. No damage ureaformaldehyde and to board.

the solution Honeycomb Paper coated (a) 5 sec. No damage to paper with urea-formaldehyde (b) 10 sec. No damage to paper and the solution (c) 15 sec. No damage to paper (d) 30 sec. Surface broken. No flame.

Concentrations used on all the above tests were approximately 1012 w/V.

In dermatitic test, the diluted solution achieved a primary irritation index of 0.38 and a classification of mild primary irritant in accordance with the FDA Handbook test for primary irritation skin test.

WHAT I CLAIM IS: 1. A flame-proofing and fire retardant composition comprising an aqueous solution of: (a) diammonium hydrogen phosphate, (b) ammonium dihydrogen phosphate, and (c) ammonium sulphate.

2. A composition as claimed in claim 1 wherein the ratio by weight of component (a) to component (c) is between 1:1.75 and 1:2.25.

3. A composition as claimed in claim 2 wherein the ratio by weight of component (a) to component (c) is about 1:2.

4. A composition as claimed in any one of claims 1 to 3 wherein the ratio by weight of component (a) to component (b) is between 1:0.8 and 1:1.5.

5. A composition as claimed in claim 4 wherein the ratio by weight of component (a) to component (b) is about 1:1.

6. A composition as claimed in any one of the preceding claims having a pH of between 5 and 8.

7. A composition as claimed in claim 6 wherein the pH is from 6.0 to 6.8.

8. A composition as claimed in claim 7 wherein the pH is 6.4.

9. A composition as claimed in any one of the preceding claims including a surface active agent.

10. A composition as claimed in claim 9 wherein the surface active agent is sodium lauryl sulphate.

11. A composition as claimed in claim 9 or claim 10 wherein the surface active agent is present in an amount of up to 0.75% by weight, based on the weight of the composition.

12. A composition as claimed in any one of the preceding claims including a binder.

13. A composition as claimed in claim 12 wherein the binder is sodium carboxymethyl cellulose.

14. A composition as claimed in claim 12 or claim 13 wherein the binder is present in an amount of up to 0.5% by weight, based on the weight of the composition.

15. A composition as claimed in any one of the preceding claims including at least one additional ammonium salt.

16. A composition as claimed in claim 15 wherein -the additional ammonium salt is ammonium sulphamate.

17. A composition as claimed in claim 15 wherein the additional ammonium salt is ammonium meta borate.

18. A composition as claimed in any one of claims 15 to 17 wherein the additional ammonium salt(s) is present in a total amount of up to 15% by weight, based on the weight of the composition.

19. A composition as claimed any one of the preceding claims including a synthetic-material etching agent.

20. A composition as claimed in claim 19 wherein the etching agent is sodium hydrogen sulphate.

21. A composition as claimed in claim 19 or claim 20 wherein the etching agent is present in an amount of up to 2% by weight, based on the weight of the composition.

22. A composition as claimed in any one of the preceding claims including a hypochlorite salt.

23. A composition as claimed in claim 22 wherein the hypochlorite salt is present in an amount of up to 0.02% by weight, based on the weight of the composition.

24. A composition as claimed in claim 22 or claim 23 wherein a chloride salt is additionally present.

25. A composition as claimed in claim 24 wherein the weight ratio of hypochlorite salt to chloride salt is between 1:8 and 1:20.

26. A composition as claimed in claim 1 substantially as hereinbefore described.

27. An anhydrous mixture which on dissolution in water yields a composition as claimed in any one of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 0.38 and a classification of mild primary irritant in accordance with the FDA Handbook test for primary irritation skin test. WHAT I CLAIM IS:

1. A flame-proofing and fire retardant composition comprising an aqueous solution of: (a) diammonium hydrogen phosphate, (b) ammonium dihydrogen phosphate, and (c) ammonium sulphate.

7. A composition as claimed in claim 6 wherein the pH is from 6.0 to 6.8.

8. A composition as claimed in claim 7 wherein the pH is 6.4.

28. A natural material (as hereinbefore described) when treated with a

composition as claimed in any one of claims 1 to 26, or a diluted solution thereof.

29. A formed material when treated with a composition as claimed in any one of claims 1 to 26, or a diluted solution thereof.