US3877952A - Flame-proofing agents, especially for use with cellulosic materials - Google Patents

Abstract

Flame proofing agents, especially useful for cellulosic materials. The agents are of the formula

WHEREIN, R1 and R2, which may be the same or different, each represents an alkyl, alkoxyalkyl or haloalkyl radical, R3 represents a mono- or multi-halogenated alkyl radical, and R4 represents a mono- or multi-halogenated alkyl radical, which may be the same as or different from that represented by R3, or an alkyl or alkenyl group.

Description

United States Patent [191 Dahmen et a1.

[451 Apr. 15, 1975 FLAME-PROOFING AGENTS, ESPECIALLY FOR USE WITH CELLULOSIC MATERIALS [73] Assignee: Chemische Fabrik Stockhausen &

Cie, Bakerpfad, Germany 22 Filed: Mar. 14, 1973 21 App]. No.: 341,187

[30] Foreign Application Priority Data Mar. 18, 1972 Germany 2213274 [52] US. Cl 106/15 FP; 252/8.1; 260/950; 260/959 [51] Int. Cl C09d 5/18; C07f 9/02; C07f 9/24 [58] Field of Search 106/15 FP; 260/950, 959; 252/8.1

[56] References Cited UNITED STATES PATENTS 3,244,586 4/1966 Rigterink 260/959 3,387,980 6/1968 Trainer et al. 106/15 FP 3,584,085 6/1971 Hartmann 260/959 3,767,736 10/1973 Burke 252/8.l

Primary Examiner--Harry Wong, Jr. Attorney, Agent, or FirmBurgess, Dinklage & Sprung ABSTRACT Flame proofing agents, especially useful for cellulosic materials. The agents are of the formula wherein, R and R which may be the same or different, each represents an alkyl, alkoxyalkyl or haloalkyl radical,

R represents a monoor multi-halogenated alkyl radical, and R represents a monoor multi-halogenated alkyl radical, which may be the same as or different from that represented by R or an alkyl or alkenyl group.

43 Claims, No Drawings FLAME-PROOFING AGENTS. ESPECIALLY FOR USE WITH CELLULOSIC MATERIALS This invention relates to flame-proofing agents. especially for use with ecllulosic materials.

It has been the practice to flame-proof articles of cellulose. such as moulded structures. foils. filaments and fibres made from untreatedcellulose or more especially regenerated cellulose. by after-treatment consisting of impregnation and/or coating with various flameproofing agents. However. these methods do not always lead to good flame-proofing and often cause deterioration in the basic articles.

Some flame-retarding agents. e.g. l-aziridinyH- phosphinous oxide and tetrakis-(hydroymethyl)- phosphonium chloride. give reasonably permanent flame-proofing but are toxic and very difficult to handle. necessitating precautionary steps. In addition. the acid catalysts frequently used with these agents may damage the cellulose (see M.W. Ranney. Flame Retardant Textiles. 1970. Noyes Data Corporation, Park Ridge. New Jersey. U.S.A., page 133 onwards and 17] onwards).

Cellulose textile articles in sheet form have been treated by precipitating phosphoamidates from aqueous solutions onto the textile so that they bcome attached thereto (see US. Pat. No. 2.828.228). Various agents are used to bring the phosphoamidate into insoluble form. However. this method is not versatile and is inconvenient to carry out.

Recently. there have been proposed various flameproofing processes in which flame-proofing agents are added to the cellulose solution (e.g. cuprammonium hydrate solution or viscose) before regeneration and are thus incorporated in the regenerated cellulose article.

However. the flame-proofing agents proposed are either relatively inaccessible. such as alkoxy phospazcnes (German Offenlegungsschriften 1,906.38]. 1.904.427; French Pat. No. 2.()l2.440'. US. Pat. Nos. 3.455.713 and 3.532.526 and British Pat. No. l.l53.955 or else. if they are accessible. lead to discolouration of the regenerated articles. such as red phosphorus (German Offenlegungsschrift l.944.056) and haloalkyl phosphates. e.g. tris-(2.3-dibromopropyl)-phosphate (US Pat. No. 3.266.918 and Dutch Application 69.14207). The use of chelates has been proposed. e.g. polyacyloxalamidrazones (German 1.932.007), but the flame-proofing effect can only be realised by a further treatment with a metal salt solution to form a deeply coloured metal chelate. which is also inconvenient.

The present invention is based on our surprising discovery of a new class of compounds which can be incorporated into cellulose articles to give excellent flame-proofing whilst substantially avoiding the disadvantages of the hitherto proposed agents.

The present invention provides a compound of the formula R o l (I) P N or (II) R Offenlegungsschrift wherein. R and R which may be the same or different. each represents an alkyl. alkoxyalkyl or haloalkyl radical. preferably containing up to 6 carbon atoms. R represents a monoor multihalosubstituted alkyl radical. preferably CH CHBrCH Br, and R represents a monoor multi-halosubstituted alkyl radical (which may be the same as or different from that represented by R.-;) or an alkyl or alkenyl radical.

Suitable alkyl radicals may be straight-chained or branched. Radicals having from 2 to 6 carbon atoms are preferred and amongst suitable radicals there may be mentioned ethyl. n-propyl. n-butyl. n-pentyl and nhexyl (straight-chained) and isopropyl, isobutyl and isopentyl (branched).

Suitable alkoxyalkyl radicals are, for example. methoxy alkyl. ethoxyalkyl. propoxyalkyl and butoxyalkyl radicals.

The halogen atom in the haloalkyl radicals may be fluorine. chlorine. bromine or iodine.

The compounds of the present invention may be prepared by methods known per se. for example by (a) condensing dialkyl halogen phosphates or alkyl dihalogen phosphates with diallyl amine, alkyl-allyl amine or N monoallyl amine in the presence of acidbinding bases such as tertiary amines. sodium carbonate or sodium hydroxide or (b) condensing dialkyl phosphite with diallyl amine. alkylallyl amine or monoallyl amine according to the Todt reaction (J. Org. Chem. l p 637 1950; J. Chem. Soc. 1945 p 660; J. Chem. Soc. 1947 p 674) to form dialkyl phosphoric acid ester-N- diallylamide or dialkyl-phosphoric acid ester-N-alkyl- N-allylamide. or alkyl phosphoric acid ester-N.N'-

tetraallylamide or alkyl phosphoric ester-N.N-dialkyldiallylamide and reacting the intermediate in conventional manner in aninert solvent. e.g. CCl with bromine or chlorine.

Instead of alkyl halogen phosphates or dialkyl phosphites one can use the alkoxyalkyl or haloalkyl ana- 40 logues.

The present invention also provides a method of producing a flame-proofed article wherein at some stage before manufacture of the final article there is incorporated into the basic material at least one compound of the formula (I) and/or (ll).

The present invention further provides a flameproofed article madefrom a basic material in which there is incorporated at least one compound of the formula (I) and/or (ll).

The compounds of the formula (I) and (II) are effective flame-proofing agents which may advantageously be used in many types of basic material. e.g. polymers. but they are especially applicable to cellulosic materials and. in particular. regenerated cellulose which is used to form rayon. artificial wool fibres and films well other shaped articles.

The compound(s) of the formula (l) and/or (ll) are preferably incorporated in an amount of from I to 40 60 percent. especially from 10 to 30 percent. by weight of the cellulosic material. e.g. regenerated cellulose. In this way. we have found that excellent and permanent flame-retarding effects are achieved whilst the difficulties and disadvantages of the hitherto proposed compounds. e.g. inaccessibility. handling difficulties. undesired effects on application properties and processing. decolourisation and instability towards wet and dry cleaning processes. are substantially avoided.

The flame-proofing agents of the formula (I) or (II) can. if required. be brought into solution in a suitable solvent to produce a pumpable consistency and for this purpose surfactants or other dispersing agents may be used to assist introduction into the cellulose solution which can be effected by stirring it into the solution or by adding it into the solution just before it leaves the nozzle during regeneration. Other substances. such as modifiers and pigmenting agents. commonly used in cellulose fibre production can. if desired. be simultaneously incorporated.

The following Examples illustrate the invention.

A. EXAMPLES l to 19 Rayon knits were prepared as follows.

As usual for common man-made fibrous celluloses. viscoses of the composition 6.75 percent cellulose. 5.8 percent soda lye. 2.2 percent sulphur were produced. The ripeness for spinning of these viscoses corresponded to gamma values of 45. After the incorporation of the amounts. quoted in the separate Examples. ofa flame-proofing agent according to the invention. if necessary diluted with an inert solvent and a surfactant. the viscoses were spun from spinning nozzles (numbering 1000. each 60 pm in diameter) into spinning baths which contained 60 g sulphuric acid. 133 g sodium sulphate and 90 g zinc sulphate per litre. The spinning bath temperature was 42C and the immersion distance of the bundle of fibres in the spinning bath 80 cm. The bundle of fibres was stretched by 80 percent in a stretching bath at 98C containing g sulphuric acid per litre and then washed and further processed in the usual manner. After drying. the fibres were processed into a yarn. the twisting of which was limited to a protective spin of 100 turns per metre. The over-all titre of the yarn was 1650 den in the blank test and increased. depending on the type and quantity of the flame-proofing agents incorporated. up to 1850 den.

From the yarns. knits were produced on straight and circular knitters. which after air-conditioning (20C. 65 percent relative atmospheric moisture) were examined regarding their combustion behaviour. For these tests. the method according to DIN 53 906 using vertically suspended test specimens was employed. the duration of action of the standard igniting flame being 10 seconds. In considering the examination results, it should be remembered that the examination conditions of DIN 53 906 were determined for fabrics so that on the one hand their application to comparatively open knits compared with fabrics. and on the other hand the low degree of twist of the entangled yarns. each represents a further increase in severity of the examination condi tions according to DIN 53 906. It was found that in particular the combustion path or carbonisation zone in the case of fabrics amounted to less than a quarter of the value given in the case of knits.

The Examples were supplemented by a blank test and by parallel tests using tris-(2.3-dibromopropyl)- phosphate. a known commercial flame-proofing agent.

The test results are given in Table 1.

To estimate the resistance of the acquired flameproofing effect to processes of wet and dry-cleaning, knits of yarns produced according to Examples 5. 7. 8 and 18 were extracted in a Soxhlet apparatus. Perchloroethylene l carbontetrachloride (2) and water (3) were used as extraction agents. The extraction time for the l0X 20 cm. approximately 8 to 9g heavy knits was 10 cycles under the action of ml extraction agent per cycle. with a total use of ml of the extraction agent. The combustion behaviour of the extracted knits was tested in accordance with DIN 53 906. (These results are also given in Table 1).

In considering the test results it should be taken into account that in the combustion tests according to DIN 53 906 a combustion path or carbonisation stretch of 20 cm corresponds to a complete combustion of the specimen. wherein the accompanying combustion time value is naturally also taken into consideration. The slight improvement of the combustion behaviour of the specimens produced according to Examples 5 and 7 after the extraction with water illustrates that the knits become thicker by shrinking.

B. EXAMPLES 20 to 25 In each case, 2g of the viscoses produced as in (A) above were drawn between two glass plates and in baths. as in (A) above. the cellulose was regenerated in the form of films. The unstretched films were washed. dried and air conditioned. The examination of the combustion behaviour of the films was carried out in a simple manner by igniting them on one edge in the flame of a bunsen burner. After removal from the flame the films were observed to see whether they burned further or extinguished themselves.

The test results are given in Table 2.

EXAMPLE l Blank test:

The viscose contained. in relation to its cellulose content. 3.26 percent of an ethoxylated aliphatic amine (20 Ato-coconut oil amine) as surfactant. (At the same time the latter acts under the described spinning conditions as a strength-improving modifier).

EXAMPLE 2 Into the viscose were introduced. in relation to its' cellulose content, 3.26 percent of the ethoxylated coconut oil amine. 3.9 percent perchlorethylene as liquefacient. and 30 percent phosphoric acid dimethoxyethyl ester-N-bis-(2,3-dibromopropyl)-amide.

EXAMPLE 3 Similar to Example 2. but using 20 percent of the above-mentioned flame-proofing agent of the present invention in the presence of 3.26 percent ethoxylated coconut oil amine. and 2.6 percent perchlorethylene.

EXAMPLE 4 Similar to Example 2. but using 3.26 percent ethoxylated coconut oil amine. L95 percent perchlorethylene and 15 percent of the above-mentioned flame-proofing agent.

Table 1 Fire- DIN 53 906 DMI FS 01/1971 proofing agent E am l Type Quan- Colour C on- Con- Loss Comb- Comb- Glow Classification in of titv o1 densed densed in ustion ustion time accordance with Application used the strength expstrength time path in the DM] Standard 9? yam g/den ansion called in or sec. for testing 92 blank sec. carbtextiles for test onizafire resistance tion cm 1 Blanktest white 3.56 12.2 0 26 2o 319 amm 2 30 3.1 I 1 1.0 12.6 0 7.5 0 non-flammable 3 20 3.3 3 12.0 6.6 0 7.5 0 non-flammable 4 l5 3.43 12.0 4.0 31 2.0 O flammable 5 30 3.12 13.4 12.3 0 7 0 non-flammable 5 after extraction by*( 1 l 30 0 8 0 non-flammable 5 after extraction by (2) 30 0 8 0 non-flammable 5 after extraction by (3) 30 0 7 0 non-flammable 5a 30 3.0 12.0 15.5 0 7 0 non-flammable So after extraction by 1 30 0 9 0 non-flammable 5a after extraction by 2) 30 (l 7 0 non-flammable 5a after extraction by (3) 30 0 7 0 non-flammable 6 20 3.28 13.4 7.9 2.5 9 0 self-extinguishing 7 30 3.10 14.0 12.8 0 7 0 non-flammable 7 after extraction by l 30 0 9 0 non-flammable 7 after extraction by (2) 30 0 9 0 non-flammable 7 after extraction by (3) 30 0 6 0 non-flammable 8 30 3.1 1 13 12.6 0 7 0 non-flammable 8 after extraction by 1) 30 0 7 0 nonflammable 8 after extraction by (2) 30 0 7 0 non-flammable 8 after extraction by (3) 30 0 5 0 non-flammable 9 White 3.08 1 1.8 13.5 0.6 l 1.5 0 self-extinguishing 9 after extraction by 3) Age- 30 0.7 10.5 0 self-extinguishing nts l0 acc- 30 2.95 12.0 17.1 1.5 14.8 0 self-extinguishing 10 after extraction by (3) ord- 30 1.7 1 1 0 self-extinguishing m 1 1 m 30 3.05 I 1.8 14.3 5 17.5 0 self-extinguishing l I after extraction by (3) the 30 4.5 0 self-extinguishing my- 12 ent- 3 15 l 1.0 l 1.7 0.5 8 0 self-extinguishing 12 after extraction by (3) ion 30 11 13 0 self-extinguishing 12 after extraction by l 30 0.5 9 0 self-extinguishing 12 after extraction by (2) 30 0.5 8.5 0 self-extinguishing 13 30 3.0 l 1.0 15.6 0 8 0 non-flammable 14 30 3.10 l 1.5 12.8 2 7.5 0 self-extinguishing 14 after extraction by (3) 30 2.8 7 0 self-extinguishing 14 after extraction by l 30 8 12 0 self-extinguishing 15 30 yellow 3.06 1 1.9 14.0 17 17 0 self-extinguishing tinged white 16 white .93 12.0 17.6 1.1 6 0 self-extinguishing 16 after extraction by (3) 40 0.9 7 0 self-extinguishing 17 30 yellow 2.87 1 1. 19.3 7.5 7 0 self-extinguishing tinged white 17 after extraction by (3) 30 7 l0 0 self-extinguishing 17 after extraction by 1 30 21 15 0 self-extinguishing 18 Comparison test 30 yellow 2.20 10.8 2 2 4 l l 0 self-extinguishing 18 after extraction with l 30 4 12 0 self-extinguishing com- 18 after extraction with (2) mer- 30 4 l l 0 self-extinguishing 18 after extraction with (3) cial 30 3.5 10 0 self-extinguishing a e- 19 [1% 20 .84 1 .4 20.6 0 20 0 flammable I l l Perchloroethylcne 12) ("arbontetmchloride (3) Water non-flammable] The classification: self-extinguishin clear and transparent corresponding with the Standard DMI FS 01/1971 (See Bekleidungsmedizin, 5/1971 published by Deutschen Medizinischen Informationsdienst e.V) [German Medical Information Service, registered.

EXAMPLE 5 To the viscose were added. in relation to its cellulose content. 3.26 percent ethoxylated coconut oil amine and 30 percent phosphoric acid di-n-propylester-N- bis(2.3-dibromopropyl)-amide.

- EXAMPLE 5a Similar to Example 5. but using 30 percent phosphoric acid di-n-propylester-N-bis-( 2.3- dibromopropyl)-amide without simultaneous addition of other substances.

EXAMPLE 6 Similar to Example 5. but with the quantity of the flame-proofing agent reduced to percent.

EXAMPLE 7 Similar to Example 5. but using 3.26 percent of the ethoxylated aliphatic amine and percent of a mixed phosphoric acid ethyl ester-N.N diallylbis-(2.3-dibromopropyl)-amide.

EXAMPLE 8 Similar to Example 7. but using phosphoric acid ethylester-N.N '-allyl-tris-( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 9 Similar to Example 5, but using phosphoric acid-diisobutylester-N-bis-( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 10 Similar to Example 5. but using phosphoric acid-di-npentylestcr-N-bis-( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 1 1 Similar to Example 5. but using phosphoric acid-di-nhexyl-ester-N-bis-(2.3-dibromopropyl)-amide as flame-proofing agent.

EXAMPLE l2 Similar to Example 5, but using phosphoric aciddimethoxyethylester-N-bis-( 2.3-dibromopropyl amide as flame-proofing agent.

EXAMPLE 13 Similar to Example 5. but using phosphoric aciddichlorocthylester-N-bis-( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 14 Similar to Example 5. but using phosphoric acidethyl-isopropylester-N-bis( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 15 Similar to Example 5. but using phosphoric aciddiethylester( N-methyl-N-2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE l6 Similar to Example 5, but using phosphoric acid-di-npropylester-N-bis-( 2.3-dichloropropyl )-amidc as flame-proofing agent.

EXAMPLE 17 Similar to Example 5. but using phosphoric acid-diisopropylester-N-bis-( 2.3-dibromopropyl )-amide as flame-proofing agent.

EXAMPLE 18 (Comparison) The viscose was mixed with, in relation to its cellulose content, 3.26 percent of ethoxylated coconut oil amine and 30 percent of tris-(2.3-dibromopropyl)- phosphate, a known commercial agent.

EXAMPLE l9 Similar to Example 18. but using 20 percent of the flame-proofing agent.

EXAMLE 20 Blank test From the viscose of Example I, films were produced and tested as described under (B) above.

EXAMPLE 2] Similar to Example 20. but with viscose according to Example 2.

EXAMPLE 22 Similar to Example 20, but with viscose according to Example 5.

EXAMPLE 23 Similar to Example 20. but with viscose according to Example 6.

EXAMPLE 24 Similar to Example 20. but with viscose according to Example 18.

EXAMPLE 25 Similar to Example 20. but with viscose according to Example l8.

SUMMARY The above Examples show that by incorporating the easily accessible flame-proofing agents of the present invention it is possible to produce uncoloured. permanently non-flammable or self-extinguishing articles from regenerated cellulose. Compared to the blanktest. some properties (e.g. feel, dye affinity and inherent colour) remain unaltered whilst others (eg resistance properties. transparency. lustre) are only slightly altered and. in any case. altered much less than with the hitherto proposed agent which only produces selfextinguishing articles of undesired colour.

One of the main advantages of the flame-proofing agents of the present invention is that good flameretarding properties can be obtained with smaller amounts of agent than has hitherto been the case. This means that, for yarns. the reduction in strength in relation to titre caused by the 'present of the agent can be kept significantly lower.

Example Fire-proofing agent Appearance Combustion behaviour Type quantity used of the foil of the foil after /1 removing the igniting flame 23 colourless. almost non flammable clear. transparent 24 Commercial 30 yellow. dull. self-extinguishing Comparison agent translucent text Comparison 20 yellow. dull. flammable. (burns text translucent further. burns up completely) What is claimed is: H that represented by R;,, or an alkyl or alkenyl l. A compound of the formula group.

- R O 0 R R 0 0 R l n 3 g n 3 (I) P N or (II) P N\ wherein. R, and R which may be the same or differand wherein R and R the alkyl. alkyl residue of the em. each represents an alkyl. alkoxyalkyl or haloalkyl alkoxy group and the haloalkyl each contain up to radical. 6 carbon atoms. and for R and R the haloalkyl, R represents a monoor multi-halogenated alkyl alkyl and alkenyl each contain up to 6 carbon radical. and atoms. R, represents a monoor multi-halogcnated alkyl and forming the material having said compound inradical. which may be the same as or different from corporated therein into a shaped article.

6. A method as claimed in claim 5 wherein the basic that represented by R;;, or an alkyl or alkenyl group, and wherein for R, and R the alkyl. alkyl residue of the alkoxy group and the haloalkyl each contain up to 6 carbon atoms. and for R and R the haloalkyl. alkyl and alkenyl each contain up to 6 carbon atoms.

2. A compound as claimed in claim 1, wherein each of R R R and R contains up to 6 carbon atoms.

3. A compound as claimed in claim 1. wherein each of R R R and R contains from 2-6 carbon atoms.

4. A compound as claimed in claim 1 wherein R represents CH- ,CHBrCH- ,Br.

5. A method of improving the flame-resistance of a shaped article which comprises incorporating into the basic material of the article a compound of the ii R3 1 1) P n or (II) material of the article is a cellulosic material.

7. A method as claimed in claim 6 wherein the cellulosic material is regenerated cellulose.

8. A method as claimed in claim 5 wherein the compound of the formula (I) or (II) is incorporated in an amount'of from 1 to percent by weight of the basic material.

9. A method as claimed in claim 8 wherein the compound of the formula (I) or (H) is incorporated in an amount of from l0 to 30 percent by weight of the basic material.

10. A method as claimed in claim 5 wherein the compound of the formula (I) or (II) is added to the basic material of the article whilst said material is in liquid form prior to formation of the shaped article.

ll. A method as claimed in claim 10 wherein the compound of the formula (I) or (II) is liquefied by a solvent before being incorporated.

12. A method as claimed in claim 11 wherein the compound of the formula (I) or (H) is incorporated in liquid form. together with a surfactant.

13. A method as claimed in claim wherein the compound of the formula (I) or (II) is added to a solution of the basic material.

14. A method as claimed in claim 10 wherein the compound of the formula (I) or (ll) is incorporatedjust before the basic material is formed into the shaped article.

15. A method as claimed in claim 14 wherein the shaped article is formed by extrusion and a dose-of the compound of formula (I) or (ll) is added just before the extrusion nozzle.

16. A shaped article made by a method as claimed in claim 5.

17. A shaped article as claimed in claim 16 which is a fibre or a film.

18. A shaped article made from a basic material into which there has been incorporated to increase flame resistance a compound of the formula wherein. R and R which may be the same or different. each represents an alkyl. alkoxyalkyl or haloalkyl radical.

R represents a monoor multi-halogenated alkyl radical. and

R represents a monoor multi-halogenated alkyl radical, which may be the same as or different from that represented by R or an alkyl or alkenyl group.

and wherein for R, and R the alkyl, alkyl residue of the alkoxy group and the haloalkyl each contain up to 6 carbon atoms. and for R and R the haloalkyl. alkyl and alkenyl each contain up to 6 carbon atoms.

19. A shaped article as claimed in claim 18 wherein the basic material is a cellulosic material.

20. A shaped article as claimed in claim 12 wherein the cellulosic material is regenerated cellulose.

21. A shaped article as claimed in claim 18 which is in the form of a fibre or film.

22. A method as claimed in claim 5 wherein each of R R R and R contains up to 6 carbon atoms.

23. A shaped article as claimed in claim 18, wherein each of R R R and R contains up to 6 carbon atoms.

24. Compound according to claim 1. wherein said compound is phosphoric acid diethyl ester-N-bis-(2.3- dibromopropyU-amide.

25. Compound according to claim 1, wherein said compound is phosphoric acid di-n-propylester-N-bis- (2.3-dibromopropyl)-amide.

26. Compound according to claim 1, wherein said compound is mixed phosphoric acid ethyl ester-N,N- diallylbis-(2,3-dibromopropyl)-amide.

27. Compound according to claim 1, wherein said compound is phosphoric acid ethylester-N,N-allyl-tris- (2.3-dibromopropyl )-amide.

28. Compound according to claim 1, wherein said compound is phosphoric acid-di-isobutyl-ester-N-bis- (2.3-dibromopropyl )-amide.

29. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-pentyl-ester-N-bis- (2.3-dibromopropyl )-amide.

30. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-hexyl-ester-N-bis- (2.3-dibromopropyl )-amide.

31. Compound according to claim I, wherein said compound is phosphoric acid-dimethoxy-ethylester-N- bis( 2.3-dibromopropyl )-amide.

32. Compound according to claim 1, wherein said compound is phosphoric acid-dichloroethyl-ester-N- bis-( 2.3-dibromopropyl )-amide.

33. Compound according to claim 1, wherein said compound is phosphoric acid-ethyl-isopropyl-ester-N- bis-( 2,3-dibromopropyl )-amide.

34. Compound according to claim 1', wherein said compound is phosphoric acid-diethylester-(N-methyl- N-2.3-dibromopropyl)-amide.

35. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-propylester-N-bis- (2,3-dichloropropyl)-amide.

36. Compound according to claim 1, wherein said compound is phosphoric acid-diisopropylester-N-bis- (2.3-dibromopropyl)-amide.

37. A method as claimed in claim 5, wherein each of R,, R R and R. contains 2-6 carbon atoms.

38. A method as claimed in claim 5, wherein R is CH CHBr-CH Br.

39. A shaped article as claimed in claim 18, wherein each of R R R and R contains 2-6 carbon atoms.

40. A shaped article as claimed in claim 18, wherein R is CH.,CHBr-CH. ,Br.

41. A method as claimed in claim 22, wherein the basic material is a cellulosic material.

42. A shaped article as claimed in claim 23, wherein the basic material is a cellulosic material.

43. A method as claimed in claim 6., wherein the cellulose is regenerated cellulose produced from viscose.

and said compound is added to the viscose.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,877,952 DATED April 15, 1975 I Kurt Dahmen and A1013 Kiinschner It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown beiow:

Column 4, lines 54-55, change "dimethoxyethyl" to --diethyl--.

Column 6, line 47, change "18" to --9-- Column 11, line 43, change "12" to --19--,

Signed and Sealcdthis A nest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner oj'Parenrs and Trademarks UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENTNO. 3,877,952

DATED A ril 15, 1975 INVENTOMS) 1 Kurt Dahmen and Alois Kiinschner It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, lines 54-55, change "dimethoxyethyl" to -diethyl--.

Column 6, line 47, change "18" to --9--.,

Column 11, line 43, change "12" to --19--.

Signcd and Sealed this Twenty-second Day Of March 1977 [SEAL] Arrest:

RUTI'I C. MASON C. MARSHALL DANN .0 Commissioner of Parents and Trademarks

Claims (43)

1. A COMPOUND OF THE FORMULA

2. A compound as claimed in claim 1, wherein each of R1, R2, R3, and R4 contains up to 6 carbon atoms.

3. A compound as claimed in claim 1, wherein each of R1, R2, R3, and R4 contains from 2-6 carbon atoms.

4. A compound as claimed in claim 1 wherein R3 represents -CH2-CHBr-CH2Br.

5. A method of improving the flame-resistance of a shaped article which comprises incorporating into the basic material of the article a compound of the

6. A method as claimed in claim 5 wherein the basic material of the article is a cellulosic material.

7. A method as claimed in claim 6 wherein the cellulosic material is regenerated cellulose.

8. A method as claimed in claim 5 wherein the compound of the formula (I) or (II) is incorporated in an amount of from 1 to 40 percent by weight of the basic material.

9. A method as claimed in claim 8 wherein the compound of the formula (I) or (II) is incorporated in an amount of from 10 to 30 percent by weight of the basic material.

10. A method as claimed in claim 5 wherein the compound of the formula (I) or (II) is added to the basic material of the article whilst said material is in liquid form prior to formation of the shaped article.

11. A method as claimed in claim 10 wherein the compound of the formula (I) or (II) is liquefied by a solvent before being incorporated.

12. A method as claimed in claim 11 wherein the compound of the formula (I) or (II) is incorporated in liquid form, together with a surfactant.

13. A method as claimed in claim 10 wherein the compound of the formula (I) or (II) is added to a solution of the basic material.

14. A method as claimed in claim 10 wherein the compound of the formula (I) or (II) is incorporated just before the basic material is formed into the shaped article.

15. A method as claimed in claim 14 wherein the shaped article is formed by extrusion and a dose of the compound of formula (I) or (II) is added just before the extrusion nozzle.

16. A shaped article made by a method as claimed in claim 5.

17. A shaped article as claimed in claim 16 which is a fibre or a film.

18. A shaped article made from a basic material into which there has been incorporated to increase flame resistance a compound of the formula

19. A shaped article as claimed in claim 18 wherein the basic material is a cellulosic material.

20. A shaped article as claimed in claim 12 wherein the cellulosic material is regenerated cellulose.

21. A shaped article as claimed in claim 18 which is in the form of a fibre or film.

22. A method as claimed in claim 5 wherein each of R1, R2, R3, and R4 contains up to 6 carbon atoms.

23. A shaped article as claimed in claim 18, wherein each of R1, R2, R3, and R4 contains up to 6 carbon atoms.

24. Compound according to claim 1, wherein said compound is phosphoric acid diethyl ester-N-bis-(2,3-dibromopropyl)-amide.

25. Compound according to claim 1, wherein said compound is phosphoric acid di-n-propylester-N-bis-(2,3-dibromopropyl)-amide.

26. Compound according to claim 1, wherein said compound is mixed phosphoric acid ethyl ester-N,N''-diallylbis-(2,3-dibromopropyl)-amide.

27. Compound according to claim 1, wherein said compound is phosphoric acid ethylester-N,N''-allyl-tris-(2,3-dibromopropyl)-amide.

28. Compound according to claim 1, wherein said compound is phosphoric acid-di-isobutyl-ester-N-bis-(2,3-dibromopropyl)-amide.

29. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-pentyl-ester-N-bis-(2,3-dibromopropyl)-amide.

30. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-hexyl-ester-N-bis-(2,3-dibromopropyl)-amide.

31. Compound according to claim 1, wherein said compound is phosphoric acid-dimethoxy-ethylester-N-bis(2,3-dibromopropyl)-amide.

32. Compound according to claim 1, wherein said compound is phosphoric acid-dichloroethyl-ester-N-bis-(2,3-dibromopropyl)-amide.

33. Compound according to claim 1, wherein said compound is phosphoric acid-ethyl-isopropyl-ester-N-bis-(2,3-dibromopropyl)-amide.

34. Compound according to claim 1, wherein said compound is phosphoric acid-diethylester-(N-methyl-N-2,3-dibromopropyl)-amide.

35. Compound according to claim 1, wherein said compound is phosphoric acid-di-n-propylester-N-bis-(2,3-dichloropropyl)-amide.

36. Compound according to claim 1, wherein said compound is phosphoric acid-di-isopropylester-N-bis-(2,3-dibromopropyl)-amide.

37. A method as claimed in claim 5, wherein each of R1, R2, R3, and R4 contains 2-6 carbon atoms.

38. A method as claimed in claim 5, wherein R3 is -CH2-CHBr-CH2Br.

39. A shaped article as claimed in claim 18, wherein each of R1, R2, R3 and R4 contains 2-6 carbon atoms.

40. A shaped article as claimed in claim 18, wherein R3 is -CH2-CHBr-CH2Br.

41. A method as claimed in claim 22, wherein the basic material is a cellulosic material.

42. A shaped article as claimed in claim 23, wherein the basic material is a cellulosic material.

43. A method as claimed in claim 6, wherein the cellulose is regenerated cellulose produced from viscose, and said compound is added to the viscose.