US2178625A - Fireproofing treatment and composition - Google Patents

Description

Patented Nov. 7, 1939 PATENT OFFICE FEEPROOFING TREATMENT AND COMPOSITION Edwin C. Clayton and Lawrence L. Hefiner, Baltimore, Md., assignors to Wm. E. Hooper & Sons Company, Baltimore, Md., a corporation of Maryland No Drawing. Application January i, 1938, [Serial No. 183,829

9 l ills,

The invention is in the nature oi an improvement in the fireproofing treatment described in our copending applications #165,168, September 22, 1937, and #556,657 filed August 17, 1935.

It relates to an initial, or primary, treatment to precede the application of the fire, water'and mildew proofing composition therein described, and to a multiple treatment consisting of one or more applications of a primary solution of water 10 soluble fire retarding agent, said solution possessing the property of penetration to a high degree, and one or more later applications of one of the compositions of said applications. The primary 1 solution may be applied by brushing, by impregnation under pressure, or by impregnation by rst subjecting the material to be treated to a vacuum andthen applying the solution by dipping or brushing, etc.

The invention furthermore particularly relates to a liquid dispersion deposited in the pores, or interstices of an absorbent material to be fireprooied, of one or more fire retarding agents which are soluble and deposited by evaporation of the solvent or to the deposit in the same location of insoluble derivatives of said agents deposited by the use of a second solution, as hereinafter described, the said deposit in each instance being effective mainly in combination with, and when covered by a main coat of a fireproof-Lug composition of the nature disclosed in said applications. This coating may effect partial impregnation with this material due to penetration. In this way a greatly improved result in the fireproofing of wood, particularly porous inflammable Wood, as wooden shingles, is attained, and the treatment of heavy grades of textiles, as the very heavy grades of cotton duck, is facilitated and rendered much more effective, and is further accomplished at less expense than by the single so process of said application. The unexpected ex= tent of the improvement accomplished has been demonstrated by actual tests. These tests were performed by burning shingles by means of a blow torch. They show the remarkable advance in efficiency gained by the improved treatment. For example, a raw cedar shingle subjected to the flame of a blow torch at eleven inches from the torch to the surface of the shingle, burns freely after twenty seconds exposure. A shingle paintfiil ed with ordinary commercial outside paint bursts into flame after six seconds of similar exposure; both shingles being completely consumed.

A shingle coated and impregnated to the degree of the ordinary absorption incident to brushing the fireproofing composition of the later application, subjected to the same test, emits a dance in ninety seconds, but the flame dies out in twenty-nine seconds after removal of the torch, there being no subsequent spread of combustion. With the torch advanced so that it is about one 5 inch from the shingle, the shingle burns in about eighty seconds, being charred in 15 seconds.

A shingle impregnated by absorption resulting from brushing with the primary solution of the invention, to be further described, and, subsequently treated with a main coat consisting of two brushings of the fireprooiing composition identified above, and slightly impregnated thereby, due to penetration by the composition, when subjected to the action of the torch flame, as in the first two tests above described, i. e., at eleven inches, after two minutes, is discolored, with no flame; in three minutes there is a slight flame, which goes out immediately. When the torch is moved up to within one inch from the shingle for go one-half minute, only the portion in direct contact with the flame, is charred, but is self-extinguished in thirty-one seconds after removal of the torch, the shingle not being destroyed or perforated. When the torch is held in the same position, about one inch from the shingle, for a further exposure of a half minute, the shingle is not destroyed or perforated, but is charred through its entire thickness. Further application of the flame perforates but does not kindle. A shingle treated with two brushings of the primary solution and one brush coat of the fireproofing composition shows signs of burning in forty-five seconds, with the torch at one inch, and is extinguished in twenty-five seconds after removal of the torch. Further exposure of the shingle for thirty seconds in the same way gives signs of burning, the flame being self-extinguished in twenty seconds after the removal of the torch, but in neither instance can the shingle be ignited so that combustion will continue after removal of the torch. By extended application at close range, it can be charred, and even perforated, but it does not support combustion, and does not flame when the torch is removed.

The primary solution, or priming solution, is a water solution of one or more water soluble fireretarding agents. It is essential that it have a high degree of penetration, preferably containing a wetting agent for this purpose. An example of a satisfactory priming solution is a water solution, containing 7% borax and 3% boric acid, and a wetting agent-various wetting agents being obtainable commercially. A sulphated ester of lauryl alcohol is a satisfactory wetting agent.

The wetting agent may be 1 or 2% by weight or volume of the solution, or more, if desired. Instead of the mixture of borax and boric acid above described, the various soluble borates may be substituted. Examples of these are: ammoni um borate, potassium borate. Theoretically, in addition to other equivalents available for this purpose, there are certain rare borates not commercially available which would otherwise be satisfactoryfor this purpose as: borates of ru: bidium, caesium and lithium. The water soluble borates, phosphates, silicates, tungstates, and various ammonium salts, also soluble halides, such as those of ammonium and sodium, are also satisfactory for this purpose.

There are also metallic salts satisfactory for this purpose, which are water insoluble, but are soluble in organic solvents. Examples of these salts are: anhydrous antimony chloride. Some of the solvents which may be used for this purpose are: carbon tetra-chloride, ethyl acetate, and other similar solvents.

The following are examples of solutions containing these salts which are satisfactory as primary solutions in the practice of the invention. These examples are numbered to distinguish them and not to indicate the order of pref erence:

1. A solution in water containing of 1% sulphated lauryl alcohol, 20% ammonium phosphate (NH4)2HPO4.

2. Substitute for ammonium phosphate, 20% sodium tungstate NazW4 21120.

3. Substitute for the ammonium phosphate, 20% sodium silicate NazSia.

4. Substitute 20% of ammonium bromide (NH4Br).

5. Substitute instead of the ammonium bromide 20% sodium fluoride NaF.

An example of a solution of a water insoluble salt which may be used for this purpose is anhydrous antimony chloride SbCls. 30% was dissolved in carbon tetra chloride.

It is also found that casein, or other nitrogen containing organic compounds may be employed in this way; the following being examples of such solution:

1. 10% borax, 5% casein, the balance water.

2. Approximately 5% sodium phosphate (Na:

P04) approx. 5% casein, approx. 5% sodium silicate (NazSiOa); approx. of 1% of gardinol, and approx. 84% water.

3. Approximately 7% sodium phosphate, approx. 5% ammonium chloride, approx. 5% ammonium sulphate, and approximately /2% Eardinol and 80% water.

4. Approximately borax, approx. 5% sodium fluoride, and approximately 84% water.

5. Approximately 8% ammonium bromide, approx. 2% ammonium carbonate, approx.'8% sodigum borate (NazBiOii approx. 3% boric acid (H3803) approximately 2% casein; sulphated lauryl alcohol approximately /2%, and approximately 76% water.

In the preferred practice of the invention, the material to be treated being impregnated with the primary solution, either by natural penetration, or absorption, or by pressure, or by first treating the material under vacuum, and then applying the solution to it, either by dipping, brushing or spraying, when the cloth, or wood to be treated is thus impregnated, the fire retarding agents are deposited by the gradual evaporation of the solvent, which is ordinarily water, but may be, under some circumstances, a volatile organic solvent forming a dispersion from a water or other solution of the tire retarding material, or in the interstices of the fabric or other product treated. The deposit may, if desired, also be accomplished by the application of a second water solution containing chemicals adapted to precipitate the fire retarding agents held in the primary solution already described, particularly the water solutions. Such precipitates are in the form of fire retarding agents, having fire retarding properties, and if thus precipitated, would be insoluble in water.

An example of this action is an initial treatment with a water solution of borax, or the equivalent, the borax, or any desired proportion of it, being rendered insoluble and thus precipitated by a subsequent treatment with a water solution of barium chloride, BaClz, or the equivalent. The borax solution may be in any desired proportion or concentrated up to the point of saturation, depending upon the desired quantity of the deposit which is, in turn, dependent upon the use to which the product is to be put. The heavier solutions will give the fire retarding effeet. The barium chloride used should to best advantage be the chemical equivalent of the borax first introduced. In this way, by the insolubilization any chance that the deposit may be removed 4 by wetting is eliminated.

The fireproofing compositions of the above cited applications with the volatile solvent therein, suitably proportioned to adapt the composition for brushing, as disclosed in application #165,168, are good examples of fireproofing compositions adapted for use in the main treatment of wood and/or fabrics, which have been treated, as described; with a priming solution. The fireproofing composition may be applied by brushing, dipping or spraying.

A composition which has been found satisfactory for this purpose contains approximately A, or 25% of approximately 60% chlorinated paraffin oil, or similary chlorinated parailin, or rubber. In any of the formulas to be given, two or more chlorinated materials may be used in the same composition. For example: 7% chlorinated rubber may be used with 18% chlorinated paraflin, or paraflin oil, the proportions being approximate, and other chlorinated materials being usable in place of chlorinated parafiin, or 10% of chlorinated rubber and or more percent of one or more of the other chlorinated materials will be satisfactory. The highest obtainable chlorination of these materials is desirable.

Another ingredient is a plasticizer tri-cresyl phosphate, of which, for example, 5% is satisfactory. This may be considerably increased, 10% or even 15% being usable. A metal borate, of which zinc borate is the most satisfactory, is also included, approximately 15% of this ingredient being employed, and the composition should also contain a pigment and filler, which, as used in the composition, comprises approximately A volatile solvent for the chlorinated material and plasticizer is necessary. This, introduced in suflicient proportions to .give the desired consistency, being regarded as satisfactory, and carbon tetra-chloride having been most generally used. The highest degree of chlorination obtainable, as to the various chlorinated materials, is satisfactory, 60% chlorination being generally regarded as suiiicient. As solvents ester solvents, such as ethyl acetate, chlorinated hydrocarbon solvent, or coal tar solvent, may be used.

The proportions of the formula are subject to main composition, or coating, may consist of a highly chlorinated material, thinned by means of a volatile solvent, or a mixture of these materials, as above suggested, used without the inert materials. fusible or otherwise, but this is mainly in circumstances where tackiness is unobjectionable, and the product is not exposed to the light or weather and less complete protection is desired.

When the painting composition is used, as a main coating, in combination with the impregnation with a liquid dispersion of fire retarding agent deposited in the material protected, by absorption of the solution containing this agent and later evaporation of the liquid, the main coating may be used in the form described or in any variation thereof, included within the above cited applications and under these circumstances the composition may be varied by the elimination of the borate, the chlorinated organic material being dissolved in a volatile solvent by which it is thinned to the desired consistency for coating, spraying or dipping. This coating composition normally includes a pigment, or filler, not essentially fusible, whereby the chlorinated material is protected from dechlorination. The plasticizer is desirable, if not essential, in effecting the adhesion of the composition and the ability to apply it, and in preserving the pliability of the material treated in case it is a fabric. Evaporation of the liquid in the priming solution may take place at any time, but trapping of the water in the material is not desirable.

Another satisfactory composition contains al proximately 27% of 60% or more highly chlorinated paraffin, or the equivalent, 8 or 10% tricresyl phosphate, or equivalent plasticizer, 45 to 50% volatile solvent, which may be carbon tetrachloride, coal tar naphtha, or any of the known volatile solvents of the chlorinated materials and the plasticizers, 4 to 6% of zinc borate, for which equivalents may be substituted, and approximately 15% of pigment and filler.

The materials composing the composition, or painting composition, may be combined in any suitable order, the borate, pigment and filler being preferably pre-ground, or mixed, by passing through or grinding in a paint mill, the solvent as well as the other materials being preferably introduced before passing through the mill, though it is not necessary to introduce all solvent before grinding.

The chlorinated material in any of the compositions named is combined in a satisfactory manner with the water, or the liquid dispersion of fire retarding ingredients contained in the pores or interstices of the materials treated, by first applying the primary solution by brushing, dipping or spraying, and then coating with the main coating, or treatment composition-4t being understood that the formula of the main coating composition may be varied from the proportions given in one formula to the proportions given in the other, and, to a reasonable extent, above and below these proportions.

The main treatment composition, or coating, which normally has a considerable degree of penetration, so that there is more or less impregnation due to this action, is subject to considerable variation in the proportions and selection of the ingredients. It being understood that sufilcient solvent is used to give the desired consistency, the solids are combined in proportions which may be stated as follows: Highly chlorinated organic material 20 to 60%; borate, or other similarly fusible material, 4 to Pigment and filler, 12

to 45%; Dlasticizer, 12 to 25%. This composition both coats and impregnates, mingling with the water dispersion or solution of fire retarding materials resulting from the primary treatment.

The new multiple process, including priming by means of a. water or other liquid dispersion of a fire retarding chemical in the pores or interstices of the wood or fabric, together with a coating with or without partial impregnation with the highly chlorinated main coating, or treatment, gives an improved result in the way of fireproofing of wood, heavy duck, and the like, far in advance of any previously suggested. The materials thus treated can be destroyed by intense great, but will not support combustion at any We have thus described a fireproofing treatment embodying our invention, the description being specific and in detail in order that the invention, and the means of applying and using the same, may be fully understood; however, the specific terms herein are used descriptively rather than in a limiting sense.

What we claim and desire to secure by Letters Patent is:

l. The method of treating fibrous cellulosic materials, as wood, cotton fabrics and the like, which consists in applying a primary treatment of a water solution of a water soluble fire retarding agent, and a wetting agent, which is absorbed by the material, the evaporation of the water forming a deposit of the fire retarding agent in the pores of the treated material, and, subsequently, coating the material by dispersion from a volatile solvent of a substantially 60% chlorinated organic substance, and a fire resisting water insoluble inert mineral solid in a finely divided form, including a low temperature fusible salt suspended in the chlorinated substance.

2. The method of treating fibrous cellulose materials to give them fire resisting properties, and also water and mildew resisting properties which comprises impregnating them with a liquid solution containing fire retarding agents, drying the material, and thereby depositing these agents within the pores of the material, and thereafter coating the material with a dispersion from a volatile solvent of the highly chlorinated organic material containing in suspension therein a finely divided solid of fire resisting quality, which protects the chlorinated material from dechlorination.

3. The method of treating fibrous cellulosic materials to give them fire, water and mildew resisting properties which comprises impregnating the material with a liquid solution containing fire retarding agents and drying the material thereby depositing the fire retarding agents within the pores of the material, and thereafter sealing the fire retarding agents within the material by coating the material being treated with a substantially 40% to chlorinated organic substance dissolved in a highly volatile solvent, said chlorinated substance containing in suspension a finely divided solid borate, which is substantially insoluble in water and which fuses and forms a fire retarding coating at the combustion temperatures of the cellulosic material being treated and a finely divided solid pigment of an opaque nature and a plasticizer; the chlorinated substance being selected from the group represented by chlorinated rubber, chlorinated paraffin oil, chlorinated vinyl resin, chlorinated tung oil, chlorinated soya, bean oil, chlorinated fish oil. said chlorinated substance being decomposed at the combustion temperatures of the cellulosic materials being treated giving 01! chlorine containing gases, said chlorinated material being solid or semi-solid at normal room temperatures and the volatile solvent being quickly evaporated at such temperatures.

4. The fire, water and mildew resisting fibrous cellulosic materials having substantially the properties of the product resulting from treatment by the process of claim 3.

5. The method of treating fibrous cellulosic materials to give them fire, water and mildew resisting properties which comprises impregnating them with a solution containing fire retarding agents and drying the materials thereby depositing these agents within the pores of the material and thereafter sealing the fire retarding agents within the pores of the material and imparting further fire, water and mildew resisting properties to said materials by coating said material with a substantially 40% to 60% chlorinated paraffln mixed with a similarly chlorinated rubber dissolved in a highly volatile solvent of said chlorinated materials the chlorinated materials containing mixed therein in finely divided form, a water insoluble borate which fuses at the combustion temperatures of the treated material, providing a coating which resists the creeping of fire, the chlorinated materials at similar temperatures giving ofi chlorine which prevents flaming, the chlorinated materials also containing mixed therein in finely divided solid form a water insoluble opaque pigment.

6. The fire, water and mildew resisting fibrous cellulosic materials having substantially the properties of the product resulting from the treatment by the process of claim 5.

7. The method of treating fibrous cellulosic materials to give them fire, water and mildew resisting properties which comprises impregnating the fibrous cellulosic materials with a liquid solution containing fire retarding agents, drying the materials being treated and thereby depositing the fire retarding agents within the pores of the treated material and thereafter coating and thereby sealing the said materials being treated with a composition containing approximately of substantially 40% to 60% chlorinated organic material consisting of chlorinated rutber and chlorinated parafiin, and a small percentage of plasticizer, the chlorinated material and plasticizer being dissolved in a highly volatile solvent of said materials and containing mixed therein in finely divided form about 15% of zinc borate and 25% of a water insoluble opaque pigment and a filler, the remainder being a solvent of the chlorinated materials which evaporates immediately at normal room temperatures.

8. The fire, water and mildew resisting fibrous cellulosic material, having substantially the properties of the product resulting from treatment by the process of claim 7.

9. The fire, water and mildew resisting fibrous cellulosic material, having substantially the properties of the product resulting from treatment by the process of claim 2.

EDWIN C. CLAYTON. LAWRENCE L. HEFFNER.