GB2046761A - Fire Retardant Compositions Containing Phosphorylated Poly-2- oxazolines - Google Patents

Abstract

A fire-retardant composition comprises a phosphorylated poly-2- oxazoline having a weight average molecular weight of at least 1000, the poly-2-oxazoline being at least 40 percent phosphorylated, and one or more inorganic salt fire-retardants. The composition is particularly useful for treating cellulosic substrates, and the rate and extent of penetration of the composition into the cellulosic substrate can be increased by using an anionic or nonionic organic phosphate ester surfactant together with a solution of the composition.

Description

SPECIFICATION Compositions Comprising Phosphate Salts of Poly-2-oxazoline and Fire Retardant and Treatment of Cel lulosic Substrates Therewith This invention relates to fire retardant compositions that are especially useful for treating various cellulosic substrates. In one aspect, the invention relates to novel compositions comprising various fireretardant formulations and poly-2-oxazolines while in another aspect, the invention relates to these same compositions containing certain surface-active agents for increasing the rate and extent of penetration of the composition into the wood and wood products.

Certain inorganic salts, e.g. phosphates, borates, sulfonates, etc., are well known fire-retardants for cellulosic substrates. However, these salts have high moisture regain properties at relative humidities in excess of 50 percent which causes the salts to migrate to the surface of a treated substrate. This migration not only depletes the salt content of the substrate, rendering it less fireretardant, but can also severely disfigure the surface.

For certain salts, this migration can be inhibited by combining the salt with a polyalkylenepolyamine. For example, Strother, U.S. Patent 3,565,679, teaches imparting fire retardancy to cellulosic substrates by treating same with a leach-resistant complex of a polyalkylenepolyamine and a condensation product of phosphorus pentoxide and ammonia. Brown and Potter, U.S. Patent 4,038,451, teach similarly except their leach-resistant composition comprises a polyalkylenepolyamine and a mixture of mono- and diammonium phosphates. Although both of these teachings disclose the use of various polyalkylenepolyamines in combination with an inorganic salt, neither discloses the phosphate salt of such a material and the superior results that accompany its use.

Further, most fire-retardant compositions must be applied to wood by a pressure treatment to achieve sufficient modification of the wood to reduce the flame-spread rating, one measure of fireretardancy. However, inorganic, fire-retardant phosphate salts, such as mono- and diammonium phosphate, polyphosphate, etc., make high solid solutions that can be applied by surface penetrating techniques, such as spray or roller coating, that results in an effective flame-spread control but upon exposure to various humidity conditions, these salts migrate to the surface. This migration not only depletes the salt content of the substrate, rendering it less fire-retardant, but can also severely disfigure the surface.Compositions containing these fire-retardant phosphate salts in combination with a partially hydrolyzed poly-2-oxazoline demonstrate substantially inhibited migratory properties but do not penetrate wood with sufficient speed and in sufficient quantity to permit their use on a production line operation employing surface penetrating techniques.

While surfactants are considered useful in surface applications generally, certain articles, such as "Treatment of Wood with Aqueous Solutions: Effect of Wetting Agents", Indus. En gin. Chem., 32, 809 (1940) by the Forest Products Laboratory at Madison, Wisconsin, Forest Service U.S. Dept. of Agriculture, have been published which teach that surfactants do not increase the rate or extent of penetration of water or solutions into the surface pores of wood. Most anionic types are generally not compatible with concentrated fire-retardant salt solutions and eventually precipitate. Many nonionic surfactants are compatible with concentrated fire-retardant salt solutions but demonstrate no effect on the rate and extent of penetration of the salt into the wood.

The present invention provides a composition comprising a phosphorylated poly-2-oxazoline having a weight average molecular weight of at least 1 000, the poly-2-oxazoline being at least 40 percent phosphorylated, and one or more inorganic salt fire-retardants.

The present invention also provides a process for treating a cellulosic substrate by simultaneously applying thereto a fire-retardant amount of a solution of the composition of the present invention and an anionic or nonionic organic phosphate ester surfactant, the surfactant being employed in an amount sufficient to increase the rate and extent of penetration of the composition into the cellulosic substrate.

The composition (as a solution) and the surfactant can be applied separately or can be applied by means of a solution comprising the composition and the surfactant.

This process method permits the application of these fire-retardant compositions to wood by production line operations employing surface penetrating techniques without sacrificing effective flame-spread control.

Virtually any inorganic phosphate salt that will impart fire retardancy to wood can be used in the practice of this invention. "Fire-retardant", "fire retardancy", and the like here mean a condition in which the tendency of wood or a wood product to normally be combusted and support or propagate flames under various conditions of temperature, oxygen availability, and the like, is retarded, deiayed, or diminished and may be attended by a tendency to extinguish or terminate combustion under certain conditions, such as charring. Mono-ammonium phosphate, diammonium phosphate, poly-phosphate and various mixtures of these materials, such as 40/60, a 40:60 mixture of mono- and diammonium phosphate, are most familiar and thus preferred.The polyphosphates include liquid fertilizer which is generally a mixture of about 60 weight percent polyphosphate with the remaining 40 weight percent consisting of mono- and diammonium phosphate.

Poly-2-oxazolines, also known as N-acylated, linear polyalkyleneimines, are used in the practice of this invention. Poly-2-oxazolines are known compounds consisting of n randomly-joined units (1,11) and are readily prepared by the ring-opening polymerization of 2-oxazolines (III), following by either full or partial hydrolysis.

The substituents and subscripts are hereinafter defined. The ring-opening polymerization of 2oxazoline monomers is generally conducted in the presence of a cationic polymerization catalyst at a reaction temperature of about 00C-2000C. Typical catalysts include strong mineral acids, organic sulfonic acids and their esters, acidic salts such as ammonium sulfate, Lewis acids such as aluminum trichloride, stannous tetrachloride, boron trifluoride and organic diazoniumfluoroborates, dialkyl sulfates and other like catalysts. This ring-opening polymerization is further descirbed by Tomalia et al., J. Polymer Science, 4, 2253 (1966), Bassiri et al., Polymer Letters, 5, 871(1967); Seeliger, German Patent 1,206,585; Jones and Roth, U.S. Patent 3,640,909;and Lit yet al., U.S. Patent 3,483,141.

The pre-hydrolyzed polymers thereby obtained are linear, N-acylated polyethylen- or polypropylen-imines having a molecular structure consisting essentially of repeating units (I). These polymers are easily converted (deacylated) to the phosphate salt by acid hydrolysis with phosphoric acid. The partially deacylated poly-2-oxazolines, i.e., the phosphate salts of poly-2-oxazolines, have a molecular structure consisting essentially of the randomly-joined units (I) and (II), illustratively depicted as:

wherein: n is the total number of units or degree of polymerization; h is the number of acylated units; and n-h is the number of phosphorylated (deacylated) units.

The term "phosphorylated" describes the product of a linear, n-acylated polyethylenimine or polypropylenimine hydrolyzed with phosphoric acid such that the hydrolyzed polymer contains at least one phosphate group ("H3PO4).

The phosphate salts of the poly-2-oxazolines here used include both the fully and partially phosphorylated polymers. Partially phosphorylated poly-2-oxazolines have at least one phosphorylated secondary amine group (V)

per polymer chain as in (IV) where n-h is at least 1. Preferably, the poly-2-oxazolines here used are at least about 40 percent phosphorylated (n-h is at least about 40 percent of n). Although fully phosphorylated poly-2-oxazolines (n-h is or is about 100 percent of n) can be used, preferably the poly-2-oxazolines are phosphorylated to a maximum of about 90 percent (n-h is about 90 percent of n) and more preferably phosphorylated to a maximum of about 70 percent (n-h is about 70 percent of n).

As regards the heretofore undefined substituents and subscripts in the above formulae, R is typically hydrogen or C1-C3 alkyl; R' is typically hydrogen, phenyl or alkyl having up to about 1 8 carbon atoms or an inertly-substituted derivative thereof; and x is 1 or 2. As used herein, "2-oxazoline" includes both 2-oxazoline monomers, i.e., x is 1, and 2-oxazine monomers, i.e., x is 2, and "poly-2oxazoline" includes both poly-2-oxazoline polymers and poly-2-oxazine polymers. By such terms as "inertly-substituted" is meant that the substituents neither preclude the polymerization of the 2oxazoline monomers nor preclude the hygroscopicity characteristics of the phosphate salts of the poly2-oxazolines. Illustrative inert substituents include halogen, alkenyl hydrocarbons, alkoxy, ester, etc.

Exemplary R substituents include hydrogen, methyl, ethyl and propyl and exemplary R' substituents include hydrogen, methyl, ethyl, propyl, pentyl, cyclohexyl, dodecyl, octadecyl, and the various halogenated, ethylenically unsaturated, etc., derivatives of each such as poly(2-trichloromethyl-2oxazoline), poly(2-isopropenyl-2-oxazoline), etc. The partially hydrolyzed phosphate salts of poly(2methyl-2-oxazoline), poly(2-ethyl-2-oxazoline),.and poly(2-H-2-oxazolines) are preferred.

Phosphate salts of poly-2-oxazolines having a weight average molecular weight of at least about 1000, as determined by the intrinsic viscosity-universal calibration curve, are used in the practice of this invention. Typically these compounds have a weight average molecular weight of at least about 10,000 and preferably of at least about 250,000. Practical considerations, such as preparation, mechanical application, and the like are the only limitations upon these compounds' average maximum molecular weight although in deference to convenience a maximum of about 1,000,000 is preferred. A maximum of about 500,000 is most preferred.

Any fire-retardant formulation that will impart fire retardance to a cellulosic substrate and is compatible with the phosphate salts of poly-2-oxazoline can be used in the practice of this invention.

These formulations are well-known in the art and generally comprise mixtures of inorganic salts (although the formulation can consist of a single salt). For example, suitable formulations include: monoammonium phosphate, diammonium phosphate, ammonium sulfate, boric acid, zinc chloride, sodium dichromate, potassium tetraborate, etc. and various mixtures of these salts, such as those described in the American Wood-Preservefs Association Standard P 10-68. Formulations comprising mixtures of mono- and diammonium phosphate are particularly preferred with mixtures containing 20 to about 80 weight percent monoammonium phosphate especially preferred. Most preferably, the fireretardant formulation comprises about 35 to about 45 weight percent monoammonium phosphate with the remainder diammonium phosphate.

The respective concentrations of the phosphate salt of the poly-2-oxazoline and the fire retardant formulation in the composition of this invention can vary widely; the exact amounts of each depending upon the substrate and the degree of both fire retardancy and hygroscopicity suppression desired. A phosphate salt of a poly-2-oxazoline concentration of at least about 2 weight percent and preferably of about 5 weight percent, is generally satisfactory. A maximum poly-2-oxazoline as the phosphate salt concentration of about 50 weight percent and preferably of about 1 5 weight percent, is used for economic reasons.Of course, the remaining weight percents consist of the fire-retardant formulation, -i.e., a minimum of about 50 weight percent and preferably of about 85 weight percent, and a maximum of about 98 weight percent and preferably of about 95 weight percent, respectively.

The composition of this invention, whether the surfactant is present or not, is applied to a cellulosic substrate in any conventional manner, e.g., spraying, painting, dipping, roll coating, reverse roll coating, pressure or vacuum treating, precipitation on fiber slurries, impregnating, etc. Typically, the composition is dissolved in an aqueous medium which is then applied to the wood or other cellulosic substrate. Sufficient composition is generally dissolved to form an aqueous solution having a concentration of at least about 5 weight percent and preferably of about 10 weight percent, solids basis. A maximum aqueous concentration of about 50 weight percent and preferably of about 20 weight percent, is used because of economics and the composition's solubility.The aqueous medium can be water per se or can be an aqueous solution or dispersion comprising other materials, such as pigments and sealers. The dissolved aqueous composition is generally applied to the substrate in an amount sufficient to either thoroughly wet the surface of the substrate or thoroughly impregnate the substrate, depending upon the method of application and the degree of protection desired. As regards surface application, on a solids base, the substrate is usually contacted with at least about 0.005 pound (0.91 g) and preferably about 0.01 pound (4.54 g) of composition per square foot (0.093 m2) of substrate surface.Practical considerations, such as economy, etc., are the only limitations on the maximum amount of composition that is contacted with the substrate, although convenience prefers about 0.05 pound (22.7 g) and most preferably about 0.03 pound (13.6 g) of composition per square foot (0.093 m2) of substrate surface.

As regards impregnation, again on a solids basis, the substrates are usually impregnated with the composition to at least about 5 weight percent and preferably to about 10 weight percent of its (substrates) untreated weight. Similar to the surface application, practical considerations are the only limitations upon the maximum amount of composition that can be impregnated into the substrate, although convenience prefers impregnating with the composition to a maximum of about 70 weight percent and most preferably to a maximum of 50 weight percent of the substrates untreated weight.

After application, the treated substance is normally dried at elevated temperatures to remove the solvent (water).

Although the composition is typically dissolved in an aqueous medium prior to its application to wood or other ceilulosic substrate, the composition can be dissolved in a suitable organic medium if desired. Suitable organic mediums solubilize both the poly-2-oxazoline and the fire-retardant formulation and can also include other materials, such as sealers and pigments. Chlorinated solvents are typical organic mediums in the absence of a surfactant and include methylene chloride, chloroform, perchloroethylene, etc. If a surfactant is used, polar soivents such as alcohols and esters are employed.

Solution and application concentrations comparable to the aqueous medium concentrations are used.

"Cellulosic substrates" include wood, wood cdmposites, wood-derived products and combinations thereof. Any cellulosic substrate capable of receiving an application of an aqueous composition comprising a phosphate salt of a poly-2-oxazoline and a fire-retardant formulation can be used in the practice of this invention. Typical examples include: wood, such as pine, cedar, oak, etc.; wood composites, such as particle- and fiberboard and plywood, etc.; wood-derived products, such as veneer and paper, etc.; and combinations thereof, such as paper-coated hard board and particle board and veneer-surfaced particle board.

Any anionic or nonionic organic phosphate ester which is compatible with a fire-retardant composition (inorganic phosphate salt plus phosphorylated poly-2-oxazoline binder) and increases the rate and extent of penetration of the composition into wood can be used in this invention.

Representative non-ionic organic phosphate ester surfactants are those of the formula

where: R" is a hydrophobic radical, typically a C4-C10 aliphatic or alicyclic hydrocarbon; and R"' is a hydrophilic radical, typically a polyalkylene glycol or glycol ether.

Both R" and R"' can be linear or branched. One compound (VI where R" is octyl and both R"' are polyethylene glycols) is an illustrative nonionic organic phosphate ester surfactant. Representative anionic organic phosphate ester surfactants are those of the formula M5R"5(PO10)2 (VII) where.

M is a neutralizing cation, such as an ion of an alkali metal, and R" is as previously defined. The compounds where M is a sodium cation and R" is 2-ethylhexyl or capryl are illustrative anionic organic phosphate ester surfactants. These surfactants can be used either alone or in combination with one another. The anionic surfactants are preferred to the nonionic.

Sufficient surfactant is here used to increase the rate and extent of penetration of the composition into the wood. A surfactant concentration (based upon the weight of the composition) of at least about 0.01 weight percent, and preferably of about 0.05 weight percent, is generally satisfactory. A maximum surfactant concentration of about 1 weight percent, and preferably of about 0.3 weight percent is used for economic considerations.

The composition and surfactant are admixed with one another either prior to or simultaneously with the application of the composition to the wood. Preferably, the composition and surfactant are admixed prior to the application of the composition to the wood and the admixture can be in any conventional manner, such as stirring or shaking. The composition and surfactant are preferably blended such that the surfactant is relatively uniformly dispersed throughout the composition. If the composition and surfactant are simultaneously applied to the wood, their application is such that the surfactant and composition are relatively uniformly mixed prior to their contact with the wood surface.

This latter admixture is most easily accompiished through spraying where the composition and surfactant are discharged from separate nozzles as mists and the individual mists comingle prior to contacting the wood surface.

The following examples illustrate the invention. Unless otherwise noted, all parts and percentages are by weight.

Examples 1-6 and Comparisons A : Hygroscopicity Oven-dried Ponderosa pine wafers were vacuum-pressure treated in aqueous solutions of various polyalkylenepolyamines (PAPA) and a fire-retardant formulation. The treating procedure comprised a vacuum for 30 minutes followed by exposure to the treating solution at atmospheric pressure and ambient temperature. The wafers were then recovered, air-dried for a minimum of two days, and then oven-dried for 18 hours at 105"C.

The aqueous treating solutions were prepared by dissolving appropriate amounts of a PAPA and a fire-retardant formulation in deionized water (450 grams) to obtain both the desired PAPA formulation ratio and solids by weight formulation. A 40 percent monobasic ammonium phosphate/60 percent dibasic ammonium phosphate fire-retardant formulation was the formulation here used, and is referred to hereinafter as 40/60. The PAPAs used were a 50 percent phosphorylated poly-(2-ethyl-2-oxazoline) (PS-PEO) having a weight average molecular weight of about 1 50,000, poly-2-H-2-oxazoline (PHO) having a weight average molecular weight of about 2000, and PEI 600, a polyethylenimine having a number average molecular weight of about 40,000 to about 60,000.

Percent solids retention was determined by subtracting the wafer's oven-dried weight before treatment from the wafer's oven-dried weight after treatment, dividing the difference thus obtained by the wafer's oven-dried weight before treatment and multiplying the resulting quotient by 100.

Moisture regain was determined by placing the oven-dried, treated wafer in a constant humidity chamber for a determined period of time, subtracting the wafer's pre-humidity chamber weight from the wafer's post-humidity chamber weight, dividing the obtained difference by the wafer's prehumidity chamber weight and multiplying by 100. Moisture regain measurements were made at 66, 75 and 90 percent relative humidities with wafers treated with each of the various aqueous treating solutions. Wafers prepared under Examples 1-6 and Comparisons A-G had a residence time of 50 days in their respective humidity chambers. Wafers prepared under Comparisons H-J had a residence time of 35 days in their respective humidity chambers.

Retention and moisture regain results are reported in Table I.

Table I Hygroscopicity Aqueous Treating Solution Moisture Regain {%J PAPA 40/60 Solids Retention % Relative Humidity Ex. PAPA (parts) (parts) (O/o) {%J 66 75 90 1 PS-PEO 6 94 10 8.7 11.7 13.5 18.3 2 PS-PEO 6 94 20 44.5 8.4 9.7 13.7 3 PS-PEO 6 94 30 70.3 7.3 8.8 12.3 4 PS-PEO 12 88 10 19.5 10.8 12.3 16.9 5 PS-PEO 12 88 20 42.8 8.9 10.6 14.5 6 PS-PEO 12 88 30 63.9 8.2 9.7 13.9 Com.

A PHO 12 88 10 18.2 11.0 13.4 18.9 B PHO 12 88 20 44.8 9.2 11.1 16.0 C PHO 12 88 30 70.8 7.6 9.6 15.8 D PEI 600 6 94 5 7.6 11.2 13.3 18.8 E PEI 600 6 94 10 15.4 11.4 12.5 17.6 F PEI 600 6 94 20 32.6 9.6 11.7 15.6 G PEI 600 6 94 30 52.5 8.3 10.2 14.6 H PEI 600 12 88 10 18.0 10.4 12.4 18.0 PEI 600 12 88 20 42.0 9.5 11.5 17.0 J PEI 600 12 88 30 70.1 8.7 10.6 17.0 Examples 7-12 and Comparisons K-M: Two-foot (0.61 m) Tunnel Test The vacuum-pressure treating procedure of Examples 1-6 was repeated (except exposure to the treating solution was at 200 psi (14.1 kg/cm2) for 30 minutes) to prepare various plywood samples for a determination of a "Flame Spread Rating". The determinations were made by following the procedures described by H. L.Vandersall, "Use of a Small Flame Tunnel in the Laboratory Evaluation of Flame Spread Rating", Special Report No. 6090 (May 5, 1964). The samples were weighed before and after each test burn to determine their weight loss. Both 50 percent (50-PS-PEO) and 85 percent (85 PS-PEO) phosphorylated poly(2-ethyl-2-oxazoline) (325,000 weight average molecular weight) were evaluated. Flame spread rating and weight loss are reported in Table II.

The data of Table II demonstrate the superior flame retardancy of wood samples treated with a phosphorylated poly(2-ethyl-2-oxazoline) 40/60 solution to those treated with a branched polyethylenimine. Indeed, the flame spread ratings for Examples 9-12 were either superior or comparable to the flame spread rating for Comparison J even though Comparison J was treated with an aqueous solution having 50 percent more solids than those of Examples 9-12.

Table II - Two-Foot (0.61 m) Tunnel Test Aqueous Treating Solution Flame PAPA 40/60 Solids Spread Wt. Loss Ex. PAPA (parts) (parts) {%) Rating (%) 7 50-PS-PEO 6 94 20 18.0 3.5 8 50-PS-PEO 6 94 20 18.0 3.5 9 50-PS-PEO 12 88 20 18.0 4.2 10 50-PS-PEO 12 88 20 21.2 4.3 11 85-PS-PEO 6 94 20 24.3 4.6 12 85-PS-PEO 6 94 20 18.0 3.7 Com.

K PE1600 12 88 10 44.0 - L PEI 600 12 88 20 30.0 - M PE1600 12 88 30 23.0 - Examples 13-16 and Controls N-Q: Two-foot (0.61 m) Tunnel Test The solutions used consisted of 94 parts of a fire-retardant salt, 6 parts of a polymeric binder and 233.3 parts of water.

Three-ply marine grade, Douglas fir, quarter-inch (0.64 cm) plywood was used. The wood was not dried before application of a solution.

Thirty-gram quantities of a solution were poured upon the surface of the wood and then spread evenly with a brush or roller. After 30 seconds for the example runs and 90-120 seconds for the control runs, any excess solution was wiped from the surface. The flame-spread rating of each treated wood sample was then made by following the procedures described by H. L. Vandersall, "Use of a Small Flame Tunnel in the Laboratory Evaluation of Flame Spread Rating", Special Report No. 6090 (May 5, 1964) available from Monsanto Co.

The flame-spread and flame-spread rating of each treated wood sample is reported in Table III.

The data of Table III demonstrates that not only does this invention produce modified wood with comparable flame-spread ratings to the modified wood of the prior art, but also produces the modified wood in about 25 percent of the time required to produce the modified wood of the prior art. Moreover, generally the modified wood produced by this invention has a superior flame-spread rating (a lower value) than the modified wood of the prior art.

Table ill - Two-foot (0.61 m) Tunnel Test) % Solids % Surfactant Flame Ex. 8 of . solids Flame- Spread Con. Solution1 Solution Surfactant2 Basis) Spread3 Rating3 N PSPEO,/ 20 - - 9.67 71.86 40/60 0 PSPEO > / 20 - - 10.33 76.75 L.F.

P PSPEO,"' 20 A 3.3 10 74.25 40/60 O PSPEO,,/ 20 A 3.3 10.5 78 L.F.

13 PSPEO,," 20 B 1.6 9.33 69.3 L.F.

14 PSPEOJ 20 B 1.6 10.88 80.45 40/60 15 PSPEO,/ 20 C 1.6 10.16 75.2 L.F.

16 PSPEOi 20 B 1.6 9.99 75.2 40/60 1. Solution Legend: PSPEOx=Polymer binder of a 50% hydrolyzed phosphate salt of poly-2-ethyl-oxazoline having a weight average molecular weight of about 125,000.

40/60=A 40% monobasic ammonium phosphate/60% dibasic ammonium phosphate inorganic fire-retardant formulation.

L.F.=Liquid Fertilizer consisting of 60% ammonium polyphosphate and 40% monodibasic ammonium phosphate.

2. Surfactant Legend: A=A compounded alkyl aryl sodium sulfonate B and C=Anionic surfactants of the formula Na5R5(P3010)2, where R is 2-ethylhexyl and capryl, respectively.

3. Average of two runs.

Claims (23)

Claims

1. A composition comprising a phosphorylated poly-2-oxazoline having a weight average molecular weight of at least 1 000, the poly-2-oxazoline being at least 40 percent phosphorylated, and one or more inorganic salt fire-retardants.

2. A composition as claimed in claim 1 wherein the weight average molecular weight of the phosphorylated poly-2-oxazoline is at least 250,000.

3. A composition as claimed in claim 1 or claim 2, wherein the weight average molecular weight of the phosphorylated poly-2-oxazoline is not more than 1,000,000.

4. A composition as claimed in any one of the preceding claims, comprising at least 2 weight percent of the phosphorylated poly-2-oxazoline.

5. A composition as claimed in any one of the preceding claims, comprising not more than 50 weight percent of the phosphorylated poly-2-oxazoline.

6. A composition as claimed in any one of the preceding claims, comprising at least 50 weight percent of the fire retardant(s).

7. A composition as claimed in any one of the preceding claims, comprising from 5 to 20 weight percent of the phosphorylated poly-2-oxazoline and from 80 to 95 weight percent of the fireretardant(s).

8. A composition as claimed in any one of the preceding claims, wherein the phosphorylated poly-2-oxazoline is from 40 to 90 percent phosphorylated.

9. A composition as claimed in any one of the preceding claims, wherein the phosphorylated poly-2-oxazoline is from 40 to 70 percent phosphorylated.

10. A composition as claimed in any one of the preceding claims, wherein the poly-2-oxazoline is poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline) or a poly(2-H-2-oxazoline).

11. A composition substantially as hereinbefore described in any one of the Examples.

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

13. An aqueous solution of a composition as claimed in any one of claims 1 to 11 having a solids concentration of at least 5 weight percent.

14. An aqueous solution as claimed in claim 13 having a solids concentration of from 10 to 20 weight percent.

1 5. A solution as claimed in any one of claims 12 to 14 which comprises an anionic or nonionic organic phosphate ester surfactant compatible therewith.

1 6. A solution as claimed in claim 1 5, wherein the phosphate ester surfactant is of the formula

or M5R115(P3010)2 (ill) where: R" is a hydrophobic radical R"' is a hydrophilic radical and M is a neutralizing cation.

1 7. A solution as claimed in claim 16, wherein R" is a C4-C10 aliphatic or alicyclic hydrocarbon radical, R"' is a polyalkylene glycol or glycol ether radical, and M is a sodium cation.

1 8. A process for treating a cellulosic substrate, which process comprises simultaneously applying thereto a fire-retardant amount of a solution as claimed in any one of claims 12 to 14 and an anionic or nonionic organic phosphate ester surfactant, the surfactant being employed in an amount sufficient to increase the rate and extent of penetration of the composition into the cellulosic substrate.

1 9. A process as claimed in claim 18, wherein a solution as claimed in any one of claims 1 5 to 1 7 is used to simultaneously apply the solution and the surfactant to the substrate.

20. A process as claimed in claim 18, wherein the solution and surfactant are separately applied to the substrate.

21. A process as claimed in any one of claims 18 to 20, wherein the surfactant is used in an amount of from 0.01 to 1 weight percent based on the weight of the composition.

22. A cellulosic substrate which has been treated by a process as claimed in any one of claims 1 8 to 21.

23. Particle board, fiberboard, plywood, veneer, paper or a combination thereof which has been treated by a process as claimed in any one of claims 18 to 21.