FR2682385A1 - Nitrogen-containing organophosphorus compounds and application to the fireproofing of (making flame-retardant) cellulose fibres - Google Patents

Abstract

The invention relates to diphosphorylimides of formula HNP2O2(OR)x(NR1R2)y. These compounds are used to improve the behaviour towards fire of cellulose fibres. The invention also relates to a mixture of diphosphorylimides of formula HNP2O2(OCH3)x(NH2)y.

Description

ORGANOPHOSPHORUS NITROGEN COMPOUNDS AND THEIR APPLICATION
THE IGNIFUGATION OF CELLULOSIC FIBERS
The subject of the present invention is phosphorus-nitrogenous organic compounds that can be used for flame retarding cellulosic fibers.

 For many textile jobs, it is desirable to have cellulosic fibers with improved fire behavior.

For this it has been proposed the use of various organic and inorganic compounds such as phosphonium salts, zinc and ammonium double basic phosphate, phosphorylamides obtained by the action of phosphorus oxychloride on ammonia, compounds halogenated compounds such as cyclophosphazenes (NPA2) n in which n is 3 or 4 and
In particular, A represents a dibromopropyl residue.

 However, these compounds failed to achieve the expected results because they did not meet the increasingly stringent requirements of the textile users mentioned below.

 Thus, flame retardants should not alter the mechanical properties of fabrics or touch them.

 They must be sufficiently reactive to be fixed on the fiber and thus not be removed by washing.

 Their flame retardancy must be permanent and not be diminished by washes. The finishes must be able to be done on conventional installations.

 After treatment, the tissues must not have toxic properties, nor release corrosive or toxic gases during combustion, hence the need to avoid the presence of halogens.

 More recently, nitrogen-containing organophosphorus compounds have been widely used but have the disadvantage of partially meeting the aforementioned requirements.

Thus, it has been marketed a composition consisting of two moles of tetrakishydroxymethylphosphonium chloride +
P (CH 2 OH) 4 Cl and one mole of urea.

 This composition is deposited on the fabric by padding and then passes through an ammonia box ensuring an early crosslinking. The fabric then undergoes a second passage in an ammonia solution and is dried.

 This procedure has several disadvantages.

 The technology used for the implementation requires having a specific material that is expensive and prohibits any mixed treatment.

 In addition, a polymeric network is formed in the cellulosic structure which gives the fabric more stiffness.

Moreover, it is possible to have so-called polycondensation "stains", indelible which are therefore unacceptable for any use of the fabric thus treated.

 The present invention provides nitrogenous organophosphorus compounds which better meet the needs and requirements of the practice and which, in particular, are used according to the usual conditions of the textile industry.

The subject of the invention is more particularly nitrogen-containing organophosphorus compounds which are sufficiently reactive to bind to the cellulosic fiber and to resist washing, conferring on the fibers thus treated a permanently improved fire behavior, said compounds being characterized in that they are diphosphorylimids Formula
HNP 2 O 2 (OR), (NR 1 R 2) Y (I) in which R represents a linear or branched aliphatic hydrocarbon radical having up to 8 carbon atoms, R 1 and
R 2, identical or different, each represents a hydrogen atom, a linear or branched aliphatic hydrocarbon radical having up to 4 carbon atoms, x and y are integers ranging from O (inclusive) to 4 (inclusive) with x + y = 4.

Among the compounds of formula (I) according to the invention, those in which x = 4 and those in which y = 4 are preferred.

With regard to the compounds of formula (I) in which y = 4, those in which R 1 represents a hydrogen atom and
R2 represents a hydrogen atom or a methyl, ethyl or propyl radical.

By way of illustration of such compounds mention may be made of di (diaminomethylphosphoryl) imide and especially di (diaminophosphoryl) imide of formula HN [P (O) 2-
As regards the compounds of formula (I) according to the invention in which x = 4, those in which R represents a methyl, ethyl or propyl radical are preferred.

 Compounds of formula (I) wherein x is 4 (y = O) and R is methyl, ethyl, propyl, butyl, hexyl are known.

 Thus the compounds in which R is methyl have been obtained in particular by RIESEL L. et al. (Z. Anorg All Chem., 430, 227, 1977) by reaction of bis (dichlorophosphoryl) imide HN [P (O) C12] 2 with methanol.

Compounds of formula (I) are also known in the formula of which y = 4, R1 represents a hydrogen atom and
R2 represents a hydrogen atom or a methyl, ethyl or propyl radical. These compounds have been described by Riesel L.

et al. (Z. Anary, All Chem, 404, pp 219-224, 1974). These authors particularly describe the compound of formula
HN [P (O) (NH 2) 2] 2 which is obtained by reaction of HN (P (O) Cl 2) 2 with liquid ammonia.

 None of the cited references has described or suggested the use of these products as flame retardants of cellulosic materials.

 The subject of the present invention is also mixtures of diphosphorylimides of the formula: ## STR5 ## in which x and y are integers ranging from O (inclusive) to 4 (inclusive) with x + y = 4.

 Among the diphosphorylimides of formula (I-a) constituting the mixtures according to the present invention, those in which y is greater than or equal to x are preferred.

By way of illustration of such diphosphorylimides, mention may be made of compounds of formula
HNP2O2 (NH2) 4, HNP2O2 (OCH3) (NH2) 3 and HNP2O2 (OCH3) 2 (NH2) 2.

 The mixtures according to the invention contain the abovementioned compounds in variable proportions, but preferably so as to obtain mixtures having overall nitrogen contents of at least 10% and preferably of between 20% and 40%.

 In general, the compounds of formula (I) can be prepared according to methods known per se.

 For example, the technique described in the articles by Riesel L. et al. previously mentioned.

The mixtures of the compounds of formula (Ia) according to the invention were prepared from the same precursor on
P-trichloro N-dichlorophosphorylemonophosphazene Cl 3 P = N-
P (O) Cl2 (abbreviated hereinafter P2NOCl5)
Thus according to a first variant 1, it is made to react
P2NOCl5 with a solution of methanol saturated with ammonia in an amount that is at most equal to 1 liter of methanol-NH3 per mole of P2NOCl5. This reaction is carried out at a temperature at most equal to 400C and preferably between -100C and + 250C for a period that can reach 20 hours or more. It is advantageously carried out in a solvent medium. The solvent must neither be reactive with respect to P2NOCl5 nor have any influence on the products of the reaction. It is advantageously of high purity and previously dehydrated.

 By way of illustration of such solvents, mention may be made of aromatic solvents such as benzene, toluene and xylene. The amount of solvent can vary to a large extent but generally 2 liters of solvent are used per mole of P2NOCl5 used.

According to a second variant 2, the reaction of secondary butanol with P2NOCl5 is carried out in a first step according to the reaction scheme.

 Stoichiometric amounts of the reagents employed are preferably used, but it would not be outside the scope of the invention if an excess of secondary butanol of up to 200 t were used.

 This reaction is carried out in a solvent medium as defined above at a temperature close to ambient temperature (250 ° C.) and under a pressure of 105 Pa.

 As regards the solvent, an amount of not more than 5 liters per mole of P2NOCl5 and preferably of between 1 and 3 liters is used.

In a second step, a solution of methanol saturated with ammonia is introduced into the medium obtained under conditions equivalent to variant 1 with the exception that at least 2 liters of the saturated methanol solution are used.
NH3 per mole of P2NOCl5.

 It would not be departing from the scope of the invention if the bis (dichlorophosphoryl) imide was isolated before the second step.

In order to isolate the mixtures obtained according to one or the other variant, the known means are generally used.
filtration of the solutions to remove the precipitate formed consisting essentially of NH4Cl and then evaporation under reduced pressure of the solvent.

 The mixtures obtained according to either variant are at ambient temperature, generally in the form of an oil.

 According to a third variant 3, operation is carried out in part as variant 2 except that a quantity of methanol solution saturated with ammonia at most equal to 1 liter per mole of P2NOCl5 is used and bubbling is carried out. ammonia in the reaction medium simultaneously with the addition of the methanol solution saturated with ammonia.

 According to this variant, mixtures are obtained which are in the form of a white solid.

To isolate it we generally operate by known means
filtration of the solution and treatment of the solid obtained to eliminate formed NH 4 Cl,
either by repeated washing with liquid ammonia,
either by treatment with diethylamine and repeated washing with chloroform.

 The molar amounts of CH 3 OH and NH 3 can be used in a very large excess with respect to the bis (dichlorophosphoryl) imide HNP 2 O 2 Cl 4 used in variants 2 and 3.

 Thus, the molar ratio CH 3 OH / HNP 2 O 2 Cl 4 is close to 50 in variant 2 and around 25 in variant 3.

 Similarly, the molar ratio NH 3 / HNP 2 O 2 C 14 is around 15 in variant 2 and close to 7.5 in variant 3.

 The mixtures obtained according to any one of the variants according to the present invention are soluble in water.

 All or part of one or the other variant leading to the mixtures according to the invention may be produced under an inert gas atmosphere such as nitrogen and at a pressure equal to or greater than 105 Pa.

 The mixtures obtained according to the present invention were characterized by phosphorus 31 nuclear magnetic resonance (31 P NMR).

 The analysis of the spectra obtained shows signals in the domains: S = + 6 to + 9 ppm and s = + 12 to 18 ppm.

 In the first one assigns the phosphorus atoms bearing group CH3O- such as -P (O) (OCH3) 2.

In the second one is attributed the phosphorus atoms bearing groups CH3O- and NH2- or NH2- alone such as
-P (O) (OCH3) (NH2)
-P (O) (NH2) 2
From the examination of the spectra it can be concluded that the number of CH 3 O- groups is greater than the number of groups
NH 2 in the case of a diphosphorylimide mixture of formula (Ia) which is in the form of oil and lower in the case of a diphosphorylimide mixture (Ia) which happens to be in the form of a solid.

 The compounds of formula (I) and the diphosphorylimide HNP 2 O 2 (OCH 3) x (NH 2) y mixtures obtained according to any one of the three variants are suitable for improving the fire behavior of cellulosic fibers, especially cotton fabrics.

 They are applied to them in aqueous solution at a concentration of at least 15% by weight and preferably between 20% and 40%.

 These aqueous solutions may be supplemented with softening agents, antifungal water repellents, wrinkles.

 It is sometimes advantageous to add nitrogenous substances such as urea or thiourea.

 The impregnation of the cellulosic fibers is carried out in particular by padding.

 The fibers thus impregnated are dried and then undergo a heat treatment in order to fix the products on the fibers.

 To this end, drying and heat treatment can advantageously be carried out continuously on a train at a temperature that can vary between 1000C and 2300C for a duration that can range from a few seconds to one hour.

 After heat treatment, the fibers are then rinsed with water at a temperature in the region of 400 ° C. to remove unbound substances.

 The fibers thus treated are resistant to washing with water, with added detergent, as well as washes with solvents known as dry washes. This stability is manifested in particular by the maintenance during repeated washings of almost the entire amount of product initially deposited.

 Another advantage is that the fibers treated with the compounds (I) or the diphosphorylimide mixtures of formula (Ia) of the present invention are provided with a resistance to combustion which allows them to rank at the highest level of incombustibility according to the NF G07 184 test authoritative in the textile industry. They satisfy the criteria of class B of said test which immediately locate them after mineral fiber-based fabrics.

 Cotton fabrics thus treated have the advantage of maintaining their flexibility.

 The following examples illustrate the invention.

EXAMPLE 1
Preparation of a mixture of formula products
HNP202 (OCH3) x (NH2) y in oily form
To 27 g of P2NOCl5 (0.1 mole) dissolved in 500 ml of benzene kept under stirring and under a stream of dry nitrogen, 14.8 g of secondary butanol (0.2 mole) are gradually added at such a rate that medium temperature does not reach 200C (room temperature).

 After 2 hours, 200 ml of methanol saturated with ammonia are added while maintaining the stirred reaction medium and under a stream of nitrogen at a rate such that the temperature of the medium remains close to 200 ° C.

 The mixture is then kept stirring for 20 hours at room temperature, at which time a precipitate is formed.

 Filtered, the benzene is removed from the filtrate under reduced pressure.

17.2 g of a product are obtained in the form of an oil which is soluble in water and which has the following characteristics:
Nitrogen content: 14.5%
NMR spectrum of 31p (solvent: water)
s = +6 to 9 ppm 3 strong signals corresponding to the P atoms of -OCH3, one of which at 8.2 ppm attributable to the compound HNP202 (OCH3) 4
S = +12 to +18 ppm several signals highlighting the presence of phosphorus atoms bearing -OCH3 and / or -NH2 which confirms the presence of products of formula

 The latter having a displacement S = 14.9 ppm.

 The NMR spectrum of 31p also makes it possible to conclude that the compound HNP 2 O 2 (NH 2) 4 is absent from the mixture.

EXAMPLE 2
Preparation of a mixture of products of formula HNP 2 O 2 (OCH 3) x (NH 2) y in solid form
To 27 g of P2NOCl5 (0.1 mole) dissolved in 500 ml of benzene kept under stirring and under a stream of dry nitrogen, 14.8 g of secondary butanol (0.2 mole) are gradually added at such a rate that medium temperature does not reach 20 "C.

 After 2 hours, 100 ml of methanol saturated with ammonia are added progressively while maintaining the stirred reaction medium under a stream of nitrogen simultaneously with the introduction of ammonia gas into the reaction medium.

 The mixture is stirred for 10 hours.

 The reaction medium is then filtered.

 35.8 g of a solid cake containing NH 4 Cl are obtained which is removed by treating the cake with a chloroform solution containing 81.4 ml of diethylamine and 150 ml of chloroform at reflux for 8 hours.

After filtration and washing of the solid residue with chloroform, 16.6 g of a solid, white, water-soluble product which has the following characteristics are isolated:
> nitrogen content: 24.7%
> NMR 31P spectrum (solvent: water)
s = +6 to +9 ppm some low intensity signals
corresponding to the P atoms of -OCH3
-P (O) (OCH3) 2. Absence of the compound HNP202 (OCH3) 4 in
The mixture.

s = +14 to +18 ppm many strong signals
highlighting the presence of P atoms
carriers of -OCH3 and / or -NH2 which confirms the presence
of compounds of formula

EXAMPLE 3
Preparation of HN [P (O) (NH 2) 2] 2 by a method analogous to that described by Riesel L. et al., (Z. anorg all Chem.

404, pp 219-224, 1974).

 3,149.5 g of P2NOCl5 (11.69 moles) in 7 714 ml of benzene are dissolved under stirring and under a stream of nitrogen in a reactor equipped with agitation.

 1733.7 g of secondary butanol (23.43 mol) are gradually added with stirring to this solution at a rate such that the temperature is close to room temperature (20-25 ° C.).

 After 12 hours, most of the solvent is removed by evaporation under reduced pressure, and then the reaction medium is diluted with 4 l of chloroform.

The reaction medium thus obtained is introduced progressively with a flow rate of 1 liter / hour into a reactor for operating under pressure, equipped with stirring and a cooling system containing 19,338 g of liquid ammonia (1,137, 5 moles) and 9 liters of
CHCl3 maintained at -200C.

 The reaction medium is then stirred for 1 hour at a temperature between -9.10C and -160C under a pressure ranging from 6.105Pa to 9.105Pa.

 After displacing the remaining ammonia dissolved in the reaction medium by flushing with nitrogen, the reaction medium is filtered.

3,656 g of a white powder containing
NH 4 Cl.

 The latter is removed by treating the obtained powder with 5 898.4 g of diethylamine (80.8 mol) and 15 l of chloroform refluxed for 6 hours.

 The washings are then washed with chloroform (15 liters per wash).

 1,494 g of a white solid are collected with a yield of 75% relative to P2NOCl5.

Product Features
Elemental analysis
Calculated for HN (P (O) (N112)] 2: P% 35.8 N% 40.5
Found: P% 36.3 N% 38.2
NMR spectrum of 31p (solvent: water)
s = +17.4 ppm (singlet)
Treatment of cotton fabrics with aqueous solutions of the products of Examples 1, 2 and 3
Pretreatment of cotton fabrics
Before impregnation, the tissues are
- Desolated (by impregnation with a solution at 60 ° C containing enzimes, fermentation at room temperature and rinsing).

 - Unclogging (action of alkaline lye or boiling sodium carbonates).

 - Bleached (using oxidizing products such as sodium hyprochlorite, hydrogen peroxide or sodium chlorite).

 - Acidified (by passing through an acetic acid bath followed by padding and drying.

# TEST 1
Fixing products on a cotton fabric
Prearation of two baths
Two impregnation baths are produced from the products prepared according to Examples 1 and 3.

The compositions are reported in Table 1.

<Tb>

<SEP> BATH <SEP> A <SEP> BATH <SEP> B
<tb> Mix <SEP> of <SEP> Example <SEP> 1 <SEP> 32 <SEP> g <SEP> 30.4 <SEP> g
<tb> Compound <SEP> of <SEP> Example <SEP> 3 <SEP> 6.1 <SEP> g
<tb> Urea <SEP> 6.4 <SEP> g <SEP> 6.1 <SEP> g
<tb> Water <SEP> 107 <SEP> g <SEP> 101 <SEP> g
<tb> Concentration <SEP> in <SEP> Product <SEP> 22 <SEP> g <SEP> 22.1 <SEP> g
<tb> in <SEP> the <SEP> bath <SEP> (in <SEP> t) <SEP>
<Tb>
Table 1
- Imprinting and fixing products on a fabric
The impregnation is carried out with a scarf whose pressure is set at 15 kg / cm of scarf length.

The removal rate is given by the formula
mF - mo
TE = X 100 where mo is the mass of
mo
the untreated sample and mF the mass of the sample after padding.

The percentage of flame retardant compound deposited is given by the formula
mF - mo
Qd = X Concentration of the bath in compound
m flame retardant expressed in percent by weight.

Table 2 summarizes the results obtained with cotton fabrics treated with bath A and bath B.

<Tb>

Tissue <SEP> treated <SEP> mO <SEP> mF <SEP> TE <SEP> (in <SEP>%) <SEP> Qd <SEP> (in <SEP>%)
<tb> with <SEP> (in <SEP> g) <SEP> (in <SEP> g)
<tb><SEP> BATH <SEP> A <SEP> 7.43 <SEP> 17.91 <SEP> 141 <SEP> 31.0
<tb><SEP> BATH <SEP> B <SEP> 7.36 <SEP> 18.13 <SEP> 146 <SEP> 32.1
<Tb>
TABLE 2
The drying and heat treatment of the fabrics thus impregnated are at 1700C for 4 minutes.

Trial 2
Resistance to washing with water
The cotton fabrics impregnated and treated as described above were machine washed at 60 ° C with a liquid detergent containing: polycarboxylates, phosphonates (<5%), anionic and nonionic surfactants (5-10). %), oxygen bleaching agents (15 to 30%) and phosphates 310 ml of detergent per 60 liters of water are used.

 During these washes, tissue samples are taken at regular intervals on which the residual phosphorus level is determined by X-ray fluorescence analysis.

 The results reported in FIG. 1 are expressed in pulse number for 200 seconds (100 seconds of counting on each face).

VESSAI 3
Resistance to dry cleaning
A fabric impregnated with a solution of the compound prepared according to Example 3 and treated under the conditions described above is subjected to a series of dry cleanings carried out by pressing.

solvent: perchlorethylene
Cvcles: 20 to 25 minutes by washing
The variations in the phosphorus content as a function of the number of washes, measured according to the method described in test 2, are shown in FIG.

TEST 4
Fire behavior
The fabrics impregnated or treated according to test 1 were subjected to fire tests according to standard NF G07 184 (December 1985) entitled: "Fire behavior-classification method according to the burned surface".

 The method involves igniting a 15 x 30 cm2 fabric test tube held vertically by a specimen holder suspended in a test chamber.

 Inflammation is caused by the combustion of a polyester - cotton primer of standardized dimensions (2.5 x 8 cm2) stapled at the bottom and in the middle of the sample.

 After testing, the destroyed surface is measured. The classification is carried out according to this surface s.

Class B <40 cm2
Class C 40 <s <100 cm2
Class D 100 <s <200 cm2
Class E s> 200 cm2
The results obtained are reported in Table 3. We can notice the absence of flash point. In addition, the measured surfaces correspond to Class B cotton fabrics.

<Tb>

<SEP> Surface <SEP> burned * <SEP> Remarks
<tb><SEP> (in <SEP> cm2)
<tb> Sample <SEP> Treated <SEP> 25.8 <SEP> - <SEP> Smokes <SEP> black
<tb> with <SEP> bath <SEP> A <SEP> - <SEP> not <SEP> of <SEP> period
<tb><SEP> of ignition
<tb><SEP> - <SEP> not <SEP> of <SEP> merge
<tb> Sample <SEP> Treated <SEP> 18.7 <SEP> - <SEP> Smoke <SEP> black
<tb> with <SEP> bath <SEP> B <SEP> less <SEP> abundant
<tb><SEP> - <SEP> not <SEP> of <SEP> period
<tb><SEP> of ignition,
<tb><SEP> - <SEP> not <SEP> of <SEP> merge
<Tb>
TABLE 3
* average of 3 measurements
VESSAI 5
We impregnated and treated a series of 12 samples of cotton fabrics with an aqueous solution of the compound prepared according to Example 3.

 The concentration of the compound impregnation bath of Example 3 is 17.4% by weight.

 After heat treatment for 3 minutes at 1800C all samples (except No. 1) are rinsed for five minutes in water at 400C to remove the unreacted product, then dried on the train.

 In order to follow the evolution of the phosphorus content on the samples, depending on the number of washes, each tissue is analyzed by X-ray fluorescence.

 The results are shown in Figure 3.

 There is a decrease in the phosphorus content at the first wash and then this rate stabilizes and remains relatively stable regardless of the number of washes performed.

 In Table 4 are collected the fire tests carried out on samples 1 to 12.

It is found that all cotton fabrics are in class B.

<Tb>

<SEP> Samples <SEP> Surfaces <SEP> burned <SEP> Remarks
<tb><SEP> (in <SEP> cm2)
<tb> 1 <SEP> (no <SEP> rinsed) <SEP> 16.67
<tb> 2 <SEP> (simply <SEP> rinsed) <SEP> 20.08
<tb> 3 <SEP> (simply <SEP> rinsed) <SEP> 19,12
<tb> 4 <SEP> (simply <SEP> rinsed) <SEP> 16.05
<tb> 5 <SEP> (2 <SEP> cleanings <SEP> to <SEP> sec) <SEP> 17,33 <SEP> Smokes <SEP> black <SEP> few
<tb><SEP> abundant
<tb> 6 <SEP> (4 <SEP> cleanings <SEP> to <SEP> sec) <SEP> 20,32
<tb><SEP> No <SEP> of <SEP><SEP> point of ignition
<tb> 7 <SEP> (6 <SEP> cleanings <SEP> to <SEP> sec) <SEP> 18.61
<tb><SEP> No <SEP> of <SEP> merge
<tb> 8 <SEP> (1 <SEP> wash <SEP> in <SEP> machine) <SEP> 20.47
<tb> 9 <SEP> (2 <SEP> washes <SEP> in <SEP> machine) <SEP> 22.48
<tb> 10 <SEP> (3 <SEP> washes <SEP> in <SEP> machine) <SEP> 21.59
<tb> 11 <SEP> (5 <SEP> washes <SEP> in <SEP> machine) <SEP> 23.77
<tb> 12 <SEP> (7 <SEP> washes <SEP> in <SEP> machine) <SEP> 22.38
<Tb>
TABLE 4
TEST 6
We carried out the impregnation and the treatment of a series of samples with aqueous solutions of the compound of Example 3 with 8 concentrations equal to 14.85% and 11.9% by weight of said compound.

 The conditions of the heat treatment vary and are reported in Table 5.

 After heat treatment, all the samples are rinsed for 5 minutes in water at 400C and then dried on the train.

 Each sample thus treated systematically undergoes 5 machine washes at 60 ° C.

 We then performed the determination of the burst index. This is defined as the pressure exerted on the tissue divided by the mass of tissue expressed in grams.

 The burst index of an untreated fabric is 47.1.

The results are collated in Table 5.

<Tb>

<SEP> Concentrations <SEP> 14.85 <SEP>% <SEP> 11.9 <SEP><SEP>%<SEP>
<tb><SEP> Treatment <SEP> 3 <SEP> mn <SEP> 2 <SEP> mn <SEP> 2 <SEP> mn <SEP> 1 <SEP> mn <SEP> 3 <SEP> mn <SEP> 2 <SEP> mn <SEP> 2 <SEP> mn <SEP> 1 <SEP> mn
<tb><SEP> Thermal <SEP> 1600 (: 1700C <SEP> 1800C <SEP> 1800 <: 1600C <SEP> 1700C <SEP> 1800C <SEP> 1800
<tb> Index <SEP> Bursts- <SEP> 30 <SEP> 30 <SEP> 24.7 <SEP> 30.5 <SEP> 32.1 <SEP> 33.2 <SEP> 29.5 <SEP> 33.2
<tb> ment
<Tb>
TABLE 5

Claims (15)

 1. Organophosphorus nitrogen compounds flame retardant cellulosic fibers, characterized in that they are diphosphorylimides of formula  Wherein R represents a linear or branched aliphatic hydrocarbon radical having up to 6 carbon atoms, R 2, identical or different, each represents a hydrogen atom, a linear or branched aliphatic hydrocarbon radical having up to 4 carbon atoms, x- and y are integers ranging from 0 (inclusive) to 4 (inclusive) with x + y = 4.  2. Compounds according to claim 1, characterized in that in the compounds of formula (I) y = 4, R1 represents a hydrogen atom and R2 represents a hydrogen atom or a methyl, ethyl or propyl radical.  3. Compound according to claim 2, characterized in that it is di (diaminophosphoryl) imide of formula HN [P (O) (NH 2) 2] 2  4. Compound according to claim 1, characterized in that in the compounds of formula (I), x = 4 and R represents a methyl, ethyl or propyl radical.  5. Diphosphorylimide mixtures of formula  HN P2O2 (OCH3) x (NH2) y (I-a) wherein x and y are integers from 0 (inclusive) to 4 (inclusive) with x + y = 4.  6. Mixtures according to claim 5, characterized in that in the formula (I-a) y is greater than or equal to x.  7. Mixtures according to claim 5, characterized in that their overall nitrogen contents are at least equal to 10 t.  8. Mixtures according to claim 7, characterized in that their overall nitrogen contents are between 20% and 40%.  9. Process for the preparation of the mixtures according to claims 5 to 8, characterized in that it consists in treating the P-trichloro-N-dichlorophosphoryl monophosphazene in a solvent medium with a solution of methanol saturated with ammonia at a temperature at most equal to 400C. .  10. Process according to claim 9, characterized in that a solution of methanol saturated with ammonia is used in an amount at most equal to 1 liter per mole of P-trichloro N-dichlorophosphoryl monophosphazene.  11. A process for preparing the mixtures according to claims 5 to 8, characterized in that it consists in performing in a first step the reaction of secondary butanol on P-trichloro-N-dichlorophosphoryl monophosphazene in a solvent medium and then in a second step. introducing into the medium obtained a methanol solution saturated with ammonia at a temperature at most equal to 400C.  12. Process according to claim 11, characterized in that a solution of methanol saturated with ammonia is used in an amount of at least 2 liters per mole of trichloro-N-dichlorophosphoryl monophosphazene.  13. Process according to claim 11, characterized in that a solution of methanol saturated with ammonia is used in an amount at most equal to 1 liter per mole of P-trichloro N-dichlorophosphoryl monophosphazene and ammonia is bubbled into the reaction medium simultaneously with the addition of methanol solution saturated with ammonia.  14. Use of the compounds of formula (I) according to claim 1 or mixtures of diphosphorylimides of formula (I-a) according to claim 5 for the fireproofing of cellulosic fibers.  15. Cotton fabric fireproofed with a compound of formula (I) according to claim 1 or a mixture of diphosphorylimides of formula (I-a) according to claim 5.