GB2402390A - Fire retardant composition - Google Patents

Abstract

A method of preparing a fire-retardant petroleum composition comprising: ```adding a petroleum polymer having a hydroxyl group to water, to form a solution. Ammonium hydroxide is then added to the said solution, subsequently followed by at least one diammonium salt or a polyphosphate having a diammonium group. A diammonium group is bound to the petroleum polymer which is then cross-linked to form a fire-retardant petroleum composition. The polymer may be polystyrene, polythene, polypropylene, acrylic polymer, or a polyurethane. The product and method of applying the product to a substrate are claimed.

Description

CElLULOSE-BASh ME Rl3TA=ANI CtOMPOSIlION BAC:ELGROUND OF THE INVENTION

This Patent Cooperation. Treaty (1?CI) apphean claims beneli:t of U S. s Serial No. 09/702,777, filed in e United States oúAmarica on November 1, 2000, the entirety of which is incorporated by reference harem.

BACKGROUND OF INVENTION

The present invention is directed to a cellulose-based fire retardant composition and to methods of maying and using such fire retardant compositions.

Cellulose and cellulosic products are considered i Blamable because Weir are readily ignited Ad are rapidly consumed after ignition When cellulose is heated to Me decomposition temperature, it yields volatile, fly le gases, as well as liquid and tarry products that may No volatize and ignite, leaving a char consisting mainly of carbon. The 9W Oberon of = "spottable for the afterglow.

:3y definition, a flame-resistant material does not support combustion and does not glow after removal of an ignition source. A Me retardautis coating or 2c integrated chemical that canes another maters to become flange resistant. To be truly efEecdve, a fire retardant should be a non-tonc polymer that is water- soluble prior to cog and insoluble aflcer I. The retardant should be non corrosive and should not emit toxic *lmes when Erring. ..

TO idea of impart flame resistance to cellulose is well krro the 0. J3L Lewis Id S. Sell, Ecology and Rest Methods of Blame Proofing of CellU106=, ame-Retdt Poller Steno, 19-lS6 (1975), Me eschew of which is incorporated by reference harem. :For practical reasons, it is pQfEa=G e; at: e ec' see ce À se that any 0e-retant effect be durable u:cder all conditions encountered by cellulosic Lateral. For example, textiles must withstand not only water, but also repeated launderings and dry clearings.

Since the question of permanence of any fire-retardant treatment is port. There are Free classes of flame-resistant compositions: (l) on- ;! durable flame retardants that are easily removed by water, or perspwabon; (A se-dura:ble treatments that reset leaching, but lose Weir effectiveness after a limited number of lauds; and (3) durable flame- retardant finishes that lo withstand leaching, laundering and dry clemg In the past, interest has been focused upon water-soluble c;EemeaLs as non-durable flame-retardg agents. lIoweYer, such agents In only unpart temporary protection, the effiec.t of Me treatment destroyed not only by is laderg, but also by raw and perspiration Periodic reprocessing libus necessary to maintain Ilame-retardeny. Because organic materials are commonly considered flammable, mostly rgPc salts and acids Ease been suggested as flame retardants. Very few moc compounds, Bush as arnmomum salts of phosphonc acid, are able to suppress bow flame propagation Ad afterglow. Ammonia phosphate Ad moinm phosphate are the most widely used non-durnble bane retardants. These salts decompose into Remora and phosphoric acid on heating.

(:ellulosic materials treated with water-soluble rgc salts must be dried carefully, since fast drying might cause crystallization of Me chemicals on the surface.

CJellulosic materials may also be treated with semi-durab1e Anne retard tint are rewired to withstand not only leaching In water, but also Invited number of Laundenngs. The most obvious means of obtaining semi- durable flame resista:cce is Ace application o-inluble slits. However, water cee' I;; jeecic insoluble orgar salts generally do not easily decompose on heating. Thus, the Ilame-retarding effectiveness of semi- durable compositions are limited to olle salts of nmphoic cations or Fiord, for enple, the phosphates or Notates Of I, zing, and alpine. Easily-reducible metal oxides are also capable of catalytically altering the course of the thermal decomposition of cellulose end combine water- nsolubilitywit ma-retarding properties. Such compounds are, for example, stypic, ferric, Ethic, chromic, zinC, cerium, bmuth, tungsten, arsenic, arid silicon oxide.

0 Phosphoric acid Ed the mmonimn salts of phosphoric and are very elective it bribing t;be combustion of cellulose. Because 1 he protection afforded by like deposition of' acid is temporary, attempts have been made to bud these compounds directly to Gel ose to obtain a durable fire retardant. The heat curing of cellulose Dim an acidic subetPnra the presence of bulTerg is agent and a swelling medimn is a suitable condition for cellulose esteridcatio The heat treatment of c.ellulose with phosphoric acid in the presence of certain nitrogen compounds Ufi leans to the formation of cellulose phone Blah fl-resistaDt properties. :En practice, the cellulose is impregnated with Me aqueous solution of the acid and Ohs nitrogenous compound. After drying, t he zo cellulose is cured at an elevated temperature.

Various other Dame or fire retardant compositions are disclosed below.

All of the patents are incorporated by reference herein Is U.S Patent No. 2,784,159 discloses flame retardant compositions containing a mixture of (1) a water-soluble salt of an oxygen-cont g acid of pentavalent phosphorous, (2) a water-soluble polyallerle polyamide; (3) a water-solle nitrogen compound,- Ed (4) a softening and wetting agent.

U.. Patent No. 3,436,250 discloser a Mod why Bee ma son resistance of fabrics are retained without yeliowg or lowering tiLe scrcgth of - a' ill '.. ;:; jher se.: À A: the fabrics by treating fabrics containing cellulose or protein fibers with an aqueous solution of a composition consisting of condensed phosphoric add and a tertiary dime or quate aim compound s U.S. Patent No 4,971,728 discloses aqueous concentrate ablated to be diluted with water and used in fire control The accent cont=;=n at least about 24% by weight of certain ure retarr3nts, parclly r phosphate; dinnrnoninm Sulfate; a blend of diammonillm phosphate and.

diammonilm sulfate; a blend of monommonium phosphate and rmoninm to phosphate hat a nitrogen to phosphorous ratio of at least bout 1.25, and a blend of monomnonum phosphate, ammoninm sulfate and mnoni phosphate having a nitrogen to phosphorus ratio of at least about 1.25.

U.S. Patent No. 5,151,127 disposes fire retardation and wood preservaiin is Impositions having inorganic salts encapsulated by a water-based acrylic resin solution The salts are carried by water into like wood or cellulose product to be treated After the water evaporates, the inorganic salts are retained ire the treated wood arid not leaded from or washed out of the wood product.

U.S. Patent No. 5,g48,148 discloses a process and product for increg Me Name resistance and thermal insulation properties of Chemically treated substances. A number of embodiments of úLme resistant composidom are disclosed, but all embodiments include a mixture contg water, morgc acids, demons salts, sodium COW Id pophoMte.

IJ.. Patent No. 6,042,639 discloser:1e-retarding and smake-;nlibiting aqueous compositions ad a method for one-step impregnation of aqueous bsorbable and normally inflmTnable materials, such as wood paper, and textiles. lithe composition comprises ammonium phosphates, phoE;phonc acid, a0 water-soluble metal salts with ability to form water-iolubl salts welsh phosphate ions andlor RmmoniT:m phosphate ions.

ceses aide;; if In dd;hon, efforts have been made to encapsulate cellulose molecules.

However, there has not been any success fire retarding a cellulose molecule.

Thus, there CQIlti=UCS to be a need for a cenulase-based fire retardant Tut s insoluble in water, has art acceptable shelf-life, is r:on-toxic and is environmentally safe.

SU3\IMARY OF INVE NOON lo According to We present invention, a cellulose molecule is treated to give the molecule fire retarr1nnt properties. We treated cellulose has stable sheli life (i.e., hate deterioration of flame resistant properties), is essenl;iy ncn-toxic when charred, and has sucien:t adhesiveness and malleili1. The cellulose based fire retardant compostion.can be wed wood and paper products, furniture, building materials, water-based pamtS, fertilizers, particle board, insulation, plywood, cement, sheet rock, carpets, linen, Og7 We e.

The fire-resistant cellulose molecule is thermally stable Red has been shown not to ignite to about 3500 F.

DETAILS) DESCRIPTION OF:CNNTION

A cellulose-based fire retardant composition according to present iverl:ion contains cellulose and can be made with or without water.

z According to a first embodiment of We present Vendor, saturated solution containing a water-solle cellulose vg hydroxyl moiety is prepped by mining cellulose powder and water. To embodiments about 4.8 gram of cellulose powder is added to about 300 ml of water. Ibe water may be pre- heated or may be heated while adding the cellulose powder, for example, to 60-70DC. Although heating not;Decessazy, * sias creesg the schibil;ty of the r=I1uIose powder the water.

l l r : ,l.e ll ce e:. À:e.d Me cellulose may be hydroxy ethyl cellulose, hydrology propyl cellulose, hydroxy isopropyl cellulose, andlor combinations hereof addition, cellulose having hydroxy butyl groups, hydroxy pencil groups andJor longer carbonyl groups may have significant f Be retardant properties and are considered as likely chemical structures to be used the present invention.

L}quid mmú8 (MIOH) it; added to the solution and like solution is Wed. After rnimng, solid dimmoninm phosphate (l.e.,fNH)aO; is added to lo the solution Irt other embodiments, the diamnonimn phosphate can be pre- mired in an aqueous solution prior to adding to the cellulose solution. The liquid Mormons can be ir, various concentrations, but In proportion to t;be concentration of the cellulose material. Age, the solution may be heated dig the addition. for example, to about 90 C for about 10-16 minutes A lbick, s viscous cellulose-based fire retardant mmposition is formed.

In other embodiments of like present invention, polyphosphates (for example, gurudine or mclame phosphates) or other &mmonin salts such as diRrnmonium sulfate, Ammonia chromate, or diammo:inm borate can tee used as an alternative, or addition, to dimnonimn phosphate.

It is believed that the reaction medhmRm is as follows. The a m moninm hydroxide bonda to the cellulose molecule. The dimmoni phosphate replaces the Prnrnonihydroxide groups on the cellulose molecule; binds to the cellulose 2s molecule, arid crosslinks with the cellulose molecule or a Etcher cellulose molecule thereby forrrnng a thick, viscous cellulose-based Bra retarrnt composition It is believed Tut the ammonium hyoxde acts as a catalyst for biding the diPmonir phosphate ndyberecgclei Gil its tIlIlIt IetItl The reaction may be shown schematically as follow, wherein C is a cellulose polymer of varying molecular chain lengths and R is a molecular radical having a hydroxy group (e.g. ethyl, propyl, butyl): 1. C-R-OH (cellulose with hydroxyl group) 2. C-R.O-N H3 (addition of ammonium hydroxide) 3. C - R- O -N H2-PO4-N H2- 0 - R - C + N H3 (addition of diammonium phosphate; replacement ofthe NH3 group with ammonia being released as vapour, and crosslinking).

The fire-retardant cellulose polymer, in its solid form, has a varying solubility in water that is related to its molecular length and the degree of cross linking. The cellulose based fire retardant composition may be insoluble in wata. The degree of cross linking and average molecular chain length may be varied by the temperature used in the reaction process.

In an embodiment according to the presort invention, the temperature ofthe cellulosic solution is increased to about 100 C so that the solution begins to boil. As the temperature of the solution is increased, the chain length shortens.

In another embodiment ofthe present invention, which does not require wata, a water-soluble cellulose having a hydroxyl moiety is added to liquid aqueous ammonia (A H40H) solution at approximately room temperature. As mentioned above, heating can be used to speed the solubility ofthe cellulose but is not required. The resulting solution is stirred, resulting in a solution that is more viscous that the solution obtained according to the first embodiment ofthe present invention. Diammonium phosphate is then added to the viscous solution.

The viscous solution may be used as a coating. Because the fire-retardant solution has adhesive properties, it may be applied to a substrate including, but e. c: a. : A: :e se ees ses: not limited to, glass, metal, wood, paper, clod, and the like. the coated substrate then dried, resulting in a fire-retardant Colitic.

other embodiments, the viscous fire-retardant liquid may be directly s added to systems such as wood, thread, carpet, mortar, and late'; Flumes without discoloring any of the systems to which it is added The systems are proce=,sed to obtain fire-retardant products,. When the fireretardant product subjected to an ion source, like cellulose chard but does DDt combust. The crossl;nked ammonia groups do not appear to silow oxygen to iamb the cellulose lo molecule. In addition, vapor is also generated when the cellulose product is contacted with incaution source. It is postulated that the cross-ling between the diammoDimn phosphate and cellulose traps water wit the cellulose polymer.

ts The present invention can also be used to fire retaped peoleTrn molecules in a similar manner. Petroleum polymers having a hydro2ry1 group and in an aqueous 601ution, such as polystyrene, polyethylene, propylene, acrylic polymers, polyuzeliharles, and the tilde may be treated withliqwd germanium and iammonium phosphate, polyphosphates, or diammomum salts, as described above.

EXAMPLES:

lixamo1e 1 z5 About 19.2 grams of hydroxy eliLyi cellulose powder novas added to about 1,900 ml water, resulting in olulion Cot,nin'; about 10% hydrous ethyl cellulose The solution was then heated to about 60-7OC. Approtely 390 ml of Eqmd PTnmonia was minced into the solution Approximately 32 gzaq of solid diem monitor phosphate was then added to the so1uo. The temperature of the solution is increased to appronrnately 90=C for about 10-15 mintite::, resultillg a thin, viscous liquid.

À ce e se e e e e e e e e e e see e e Eple 2 About 4.8 of hydroxy ethyl cellulose powder IS addod to about go m7 Of liquid ammonia at approve ately room temperature. The result solution was stirred for about 30-45 minutes. Eight grams of dimoni1, - phosphate was then added and stirred into t he soluhan Until a clear solution was obeyed lc solution was avowed to cronslink for about 94 hours, resulting in a Mae viscous solution than that obtained according to Ample 1.

lo Example 3

About 4.8 g of bydroy ethyl cellulose powder was added to about 8Q ml of liquid ammonia at approximately room temperature. Tne solution was then heated to about 60-70 C and was stirred for about 30-45 minutes. Eight grams of diammoninm phosphate was then added and s1imd into the solution und1 a iS clear solution was obteL The temperature of the solution was increased to about 60-70CC and then to apprately 90 C for about 10-15 minutes. Ibe solution croselinked, resulting in Er viscous solution trample 4 zo Tissue paper was dipped the solution obtained according to Example 1 and mowed to dry ambient air, in a microwave, or by using a hair dryer.

The treated tissue paper was then contacted Prim a flee Tom a match, a butane lighter, or a propane torch. The tissue paper charred, but did not Is combust.

Temple 5 Cardboard was coated with a solution obtained according to Example 1 and allowed to dry ambient air, a owave, or by using a he her. g

À oe À He C À C C À À c À À À À À À À À À À À The treated cardboard was then contacted him a dame from a match, a butane lighter, or a propane torch. The cardboard Marred, but did not co;cabust.

Example 6

s A lien sheet was dipped e solution obiq;ned according to Example 1 and allowed to dry in a clolibes dryer.

He dried treated sheet was liben contacted with a fume from a match, a butane lighter, or a propane torch. The sheet Bred, but did not combust.

The foregoing disclosure has been set forth merely to illustrate the invezltion and is not mte.nded to be limiting Singe morlifirations of We disclosed embodiments innnrporatg the split and substance of t;ke invention may occur to persons skilled the art, the mention should be construed to include is ereryg vilihin the scope of the appended claims and equivalents Hereof. c

Claims (14)

ee c À À À À À CLAMS

1. A method of preparing a fire-retardant petroleum composition, comprising: adding a petroleum polymer haying ahydroxyl group to water, thereby forming a solution, adding ammonium hydroxide to the solution, subsequently adding at least one 1iammonium salt or a polyphosphate having a diammonium group to the solution and binding a diammonium group to the petroleum polymer, and crosslinking the petroleum polymer, thereby forming a fire-retardant petroleum composition.

2. A method of preparing a fire-retardant petroleum composition, according to Claim 1, wherein the at least one diammonium salt comprises diammonium phosphate.

3. A method according to Claim 1, wherein said petroleum polymer is selected from the group consisting of polystyrene, polyethylene, polypropylene, acrylic polymers, pourethanes, and combinations thereof

4. A method according to Claim 1, further comprising heating the water prior to adding the petroleum polymer.

5. A method according to Claim 1, furler comprising heating the solution after at least one of adding the petroleum polymer, adding the ammonium hydroxide, adding the at least one diammonium salt, or Wang the polyphosphate.

6. A method according to Claim 1, wherein the at least one diammonium salt is selected from the group consisting of diammonium phosphate, diammonium sulfate, c. . . c c 8 À e I e À À 8 e 8. ..e e À e see e À À À Àe À À À e diammonium chromate, diammoni am borate, amd combinations thereof

7. A method according to Claim 1, wherein the polyphosphate comprises gnidine phosphate or melamine phosphate.

8. A method of preparing a fire-retardant petroleum composition, comprising: adding a petroleum polymer having a hydroxyl group to liquid ammonia to form a solution, subsequently adding diamonium phosphate to the solution and binding diammoninm phosphate groups to the petroleum polymer; and crosslinking Me petroleum polymer, thereby forming a fre- retardant petroleum composition.

9. A method of preparing a fre-retart petroleum composition according to Claim 1, comprising: adding one or more petroleum polymers having a hydroxy group to water, thereby forming a solution, catalytically binding the diammonium group to the one or more petroleum polymers in solution; and crosslinking the one or more petroleum polymers, thereby forming a fre-retardant petroleum composition.

10. A fre-retardant petroleum composition prepared by a method of any one of Claims 1-9.

11. A petroleum-based fire retardant comprising one or more petroleum molecules having an oxygen atom from a hydroxyl group, wherein said one or more petroleum molecules are crosslinked by a diammonium moiety.

À 1 À À e À À À À À À À À À À À À À À

12. A peoleum-based fire retardant according to Claim 11, wherein the diammonillm moiety is diammonium phosphate.

13. A method for providing fire retardant properties to a product, comprising: coating a product with a fire-retardant petroleum composition according to Claim 10, and drying the coated product, thereby forming a fire-retardant coating.

14. A method for providing fire retardant properties to a product, comprising: adding a fire-retardant petroleum composition according to Claim 10 to a slurry or suspension; and evaporating a portion of water from said slurry or suspension, thereby forming a fire-retardant product.