GB1575649A - Flameproof and fireproof products - Google Patents

Description

(54) FLAMEPROOF AND FIREPROOF PRODUCTS (71) We, ARCO POLYMERS INC., a Corporation organised under the laws of the State of Pennsylvania, United States of America of 1500, Market Street, Philadelphia, Pennsylvania 19101, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- A wide variety of materials used heretofore as materials of construction are fire-unstable i.e. they burn or melt or otherwise heat-degrade to the point of evolving inflammable volatile gases or losing their dimensional stability when in contact with flame or heat.Such fire-unstable materials of construction, whether in the form of discrete regular or irregular particles or in the form of sheets or boards or laminates, such as polymeric materials, expanded polystyrene beadboard, polyurethane foam, cork, wood particle board and glass fiber batting, have therefore had to be protected against fire by means of thermal barriers.

Expanded polystyrene beadboard is a material of construction which has proven to be particularly difficult to protect against fire due to its low glass transition or softening point temperature, e.g., about 100"C for polystyrene having a molecular weight equal to or greater than about 50,000. The previous attempts to improve the performance of expanded polystyrene beadboard under fire using either self-extinguishing or flame retardant additives have been inadequate. The socalled chemical flame retardants using halogens, peroxides, phosphorous and/or metallic oxides, such as antimony trioxide and molybdenum trioxide, did nothing to reduce the thermoplasicity of the polystyrene upon exposure to flame and very little to raise the flame resistance.Similarly, the precoating of the polystyrene beads prior to moulding with thermoplastic resins or thermosetting foamed resins have been unsuccessful in effectively reducing the inflammability of the polystyrene products. The most that can be said of the prior art additives is that they can be self-extinguishing agents, namely, that when the flame is taken away from the exposed polystyrene the flame extinguishes. Because of this, the present fire regulations in the U.S.A. impose the use over the polystyrene insulation product of a + inch thick portland cement plaster or gypsum board which increases the safety factor in the event of fire by retarding the smoke evolution and reducing flame propagation.

In accordance with the present invention, a flameproof and fireproof product comprises an article coated with a coating material which starts to intumesce at a temperature of from 75 to 1 500C on exposure to a flame or heat, to form a thermal insulating foam barrier on the article, and the foam barrier is such that it becomes a porous uninflammable char or residue on continued exposure to the flame or heat.

The invention is of value in the protection of fire-unstable materials and particularly of polymeric materials, polystyrene beads and foam, and also polyurethane foam, cork, wood particles, glass fibres and similar materials of construction. Other fire-unstable materials which can be protected include natural or foamed thermoplastic materials or synthetic thermoplastic materials, such as polyethylene, polyvinyl chloride and copolymers of styrene and ethylene. The fire unstable material can be in the form of discrete particles of regular, irregular or fibrous shape or in the form of sheets or boards or laminates. The invention may also be applied to those materials considered fire-stable, e.g., steel, aluminium, and other metals and alloys.

The coating material, prior to hardening, can be applied to the fire-unstable material as a coating or matrix for particulate material or as a coating and matrix for sheet or particle board material or as a coating, matrix and laminating adhesive layer in the formation of laminates from two or more identical or dissimilar sheets or boards.

The hardened coating material is capable of starting intumescing (after softening and flowing) at a temperature of 75 to 1500C which is appreciably below the incipient temperature of intumescence of the heretofore known fire-retardant intumescent coatings and is at or below about the maximum of the temperature range at which many fire-unstable materials degrade to the point of evolving flammable gases or losing its dimensional stability. Upon application of flame or heat, the coating material copiously intumesces to form a thermal insulating foam barrier which preferably has a low foam density of from 0.2 to 2 pounds per cubic foot and a generally closed, finely divided cell structure upon the fire-unstable material. Upon continued exposure to heat or flame for an appreciable time, the thermal insulating foam barrier will become a porous char or residue.The porous char or residue is uninflammable, has adequate insulation strength and flame resistance to prevent flaming and the usual heat-degradation of the fire-unstable material so that the fire-unstable material does not heat-degrade for a prolonged period of time to the point of evolving inflammable volatile gases or losing its dimensional stability. The low temperature intumescence and thermal barrier insulating characteristics of the coating material, 'therefore, protect the coated fireunstable material, including even polystyrene foam.

In contrast to prior definitions of "intumescent" in which the foaming and charring of the intumescent material were considered simultaneous, the term "intumescent" in the present invention means the formation of a protective insulating foam. The foam appears as a stable heat-resistant, coherent entity which is uninflammable and has strength enough to be significantly resistant to further heat or flame. It is sometimes yellow or orange in colour and does not char and turn black except on continued or sustained exposure to high heat or flame.

The start of intumescence of the coating material can be measured by a Thermomechanical Analyzer which permits visual and temperature readings for the dimensional and viscoelastic changes in a solid-state sample heated in a standard furnace. Temperature programming of the instrument is provided. In tests on various coating materials embodying the present invention at a programmed temperature increase of 10 C degrees per minute, intumescent started as low as 750C and as high as 1500C, although softening and slight flow of the coating was noticed at temperatures in the approximate range of 1000C-1200C ald when considerably below the temperature at which intumescence started.Most of the samples tested started intumescing in the range of 1000C-1200C and when intumescence did not start until about 1400C-1500C, the amount of intumescence was reduced. Commercially available fire-retardant intumescent coatings, on the other hand, showed a start of intumescence at higher temperatures of 1600C to 260"C when tested in the same manner.

The coating material is present on the fire-unstable material in a weight ratio which is preferably of from 0.04:1 to 4:1, more preferably of from 0.4:1 to 2:1 and most preferably of about 1:1. As a general rule, the higher the-weight ratio of the coating material to the fire-unstable material, the greater the flame-proofing and fireproofing. Cost factors may impose a limitation on this weight ratio.

The hardened coating material preferably comprises the resinous reaction product of (a) a liquid resin former with (b) a liquid hardener. The liquid resin former is preferably reacted with the liquid hardener in a weight ratio which is usually of from 1:10 to 10:1 more preferably of from 1:2 to 6: 1, and most preferably of about 1:1. The hardening reaction takes place at ambient temperature (or above to decrease reaction time) when the coating material is self-hardening and is effected at slightly elevated temperature when the coating material is heathardenable.

Desirable liquid resin formers are disclosed in U.S. Patent Specifications Nos.

3,551,365; 3,808,159 and 3,824,200 and comprise the liquid polymeric product of a heated blend of (a,) from 25 /n to 800/n by weight, and preferably from 370/ to 78 /n by weight, of a reducing sugar, (a2) from 50/ to 62 /n by weight, and preferably from 15% to 45 /n by weight, of 85 /n strength phosphoric acid (H3PO4) (a3) from 2% to 20% by weight, and preferably from 4% to 15% by weight, of at least one fluidifier and (a4) from 0% to 15 /n by weight, and preferably from 1% to 4% by weight, of a polyhydric phenol having at least two hydroxy groups in a meta position relative to one another. Representative examples of suitable reducing sugars include monosaccharides and disaccharides, such as dextrose and commercial glucose produced by hydrolysis of carbohydrates, fructose, galactose, mannose, lactose, and their blends with higher saccharides such as are found in corn syrup, starch and flour, with dextrose being preferred. Cane sugar or sucrose, however, cannot be used because it is a non-reducing sugar. The phosphoric acid is generally of 85% strength, although lower strength phosphoric acid can be used, provided compensation is made by a reduction of the free water present in the reaction mixture when water serves as a fluidifier of the reaction mixture.Suitable fluidifiers include water and/or dihydric or polyhydric C18 aliphatic alcohols, such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol and glycerol.

The preferred fluidifier is water, because the presence of the dihydric or polyhydric aliphatic alcohols may tend to produce an inflammable atmosphere and increase surface flash upon subjecting the hardened coating material to flame. Useful polyhydric phenols having at least two hydroxy groups in a meta position relative to one another, which polyhydric phenols improve the hardness of the hardened coating material and its stability to moisture, include resorcinol, pyrogallol and phloroglucinol. The liquid resin former is preferably a reducing sugar copolymer or terpolymer containing chemically bound repeating acidic phosphate groups or units therein and repeating phenolic groups or units, when the phenolic reactant is used in its preparation. Small amounts of urea, as discussed hereinafter, can also be incorporated into the liquid resin former.

The liquid resin former may be prepared by dissolving or dispersing the reducing sugar in the fluidifier, which generally is water. When the solution or dispersion is obtained, the polyhydric phenol, when used, is then added with stirring and this is followed by the addition of part or all of the phosphoric acid. The system is brought to the boil (or below the boil when heating under elevated pressure) and maintained at about 115"C to 1300C for a period of 5 to 20 minutes or longer after which it is cooled to ambient temperature with the further addition of any balance of phosphoric acid. This system can be maintained at a higher temperature as the initial water content is reduced.

Representative examples of formulations used for preparing the liquid resin former (RF) are given in the following Table I: TABLE I Liquid Resin Former (RF) Percent by Weight ( /O) Formulation No. (RF-) 1 2 3 4 5 6 7 8 9 10- 11 12 Components: Phosphoric acid (85%) 43 41 36 31 31 29 24 20 38.5 41 33 37.5 Water - 3 5 6 4 6 - 2.9 3 5 2.5 Diethylene glycol 3 Polyhydric phenol, e.g., resorcinol 6 - - 6 4 - Reducing sugar, e.g., dextrose or commer cial glucose 54 56 - 57 65 65 76 80 52.6 - 44 38 Starch - - - - - - - - - 56 - Flour - - 59 - - - - - - - - Urea - - - - - - - - 6 - 14 16 Oxalic acid - - - - - - - - - - - 2 Diammonium phosphate - - - - - - - - - - - 3 Monoethanolamine - - - - - - - - - - - 1 Any suitable hardener can be used in conjunction with the liquid resin former to prepare the reaction product therebetween so long as the hardener is capable of gradually hardening the liquid resin former at ambient temperature or at slightly elevated temperatures and is liquid and further provided that the reaction product therebetween is characterized by low temperature intumescence, at from 75 to 1500C, to form a voluminous thermal insulating low density foam barrier.The preferred hardener contains formaldehyde and particularly urea-formaldehyde compounds having a mole ratio of formaldehyde to urea of from 1:1 to 2:1. The hardener may be in the form of a mixture of materials which mixture may form polymers or blends of polymers. Typical examples of formaldehyde hardeners include formaldehyde and furfuryl alcohol; formaldehyde and urea; formaldehyde, urea and furfuryl alcohol; formaldehyde, urea and glucose; and formaldehyde, urea, furfuryl alcohol and glucose. In the above formaldehyde hardeners containing furfuryl alcohol and urea, the mole ratio of urea to furfuryl alcohol should be above 1:1 and up to 9:1, while in those hardeners containing glucose the mole ratio of urea to glucose should be from 6:1 to 2:1.In preparing such formaldehyde hardeners, there can be present caustic soda (sodium hydroxide), capric acid and fluidifiers, such as cyclohexanol, diethylene glycol, glycerol and hexylene glycol. The formaldehyde used preferably is in the form of paraformaldehyde.

By way of example, the hardeners can be prepared according to one procedure by charging the reactor with the caustic soda (when used), water, alcoholic fluidifiers (when used), furfuryl alcohol (when used) and the paraformaldehyde; heating to 1150C--1200C for 1030 minutes or until clear; cooling to 850C-900C (where necessary); adding the glucose (when used); heating to 1150C--1200C for 5-25 minutes or until clear; cooling to 800C-850C (where necessary); adding the urea (when used); heating to 1 100C-1200C for 2-25 minutes or until clear; adding the capric acid (when used); heat to 1150C--1200C for about 10 minutes; cooling and discharging the reactor. Alternatively, the hardeners may be prepared by charging the reactor with the water and glucose; adding the urea (when used) to the aqueous solution of glucose; heating to 1 150C-- 1200C for about 15 minutes or until clear; cooling to 700C (where necessary); adding the caustic soda and fluidifiers, furfuryl alcohol (when used) and the paraformaldehyde; heating to 1100C--1200C for 20 to 30 minutes or until clear; adding the capric acid (when used); heating to 1150C--1200C for about 10 minutes; cooling and discharging the reactor.

Representative examples of formulations used for preparing the liquid formaldehyde hardener (H) are set forth in Table II below.

TABLE II Formaldehyde Hardener (H) Percent by Weight (%) Formulation No. (H-) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Components: Paraformaldehyde 16 24.0 27.0 21.9 24.4 25.4 26.2 25.8 25.8 35.3 30.7 40.1 25.4 23.8 24.4 26.9 Furfuryl alcohol 84 57.0 49.0 24.2 12.7 9.8 5.4 - - 22.4 6.0 - - - 5.1 Urea - 15.9 20.0 22.7 27.8 29.2 30.4 30.6 30.6 38.2 39.6 46.6 29.5 27.6 28.3 29.8 Glucose - - - 27.3 29.0 29.4 30.4 30.6 30.6 - 19.7 - 29.5 40.7 35.1 35.7 Cyclohexanol - - - - - - - 2.3 - - - - - - - Glycerol - - - - - - - - 2.3 - - - - - - Diethylene glycol - - - - - - - 3.1 - - - - - - - Hexylene glycol - - - - - - - - 3.1 - - - - - - Sodium hydroxide - 1.4 1.2 1.2 2.5 2.6 3.6 3.6 3.6 2.9 2.3 3.4 3.5 3.3 3.4 3.8 (3% soln.) Water - 1.0 2.1 2.7 3.6 3.6 4.0 4.0 1.0 1.5 9.6 12.1 4.6 3.7 3.8 Capric acid - 0.7 0.7 - - - - - - 0.2 0.2 0.3 - - - - The flameproof and fireproof characteristics of the product of the invention can be further improved by the preferred embodiment thereof wherein the coating material further contains a small amount of from 0.02 part to 0.3 parts by weight per 1 part by weight of the liquid resin former of an expanding or blowing agent, such as urea, ammonium phosphate, ammonium sulfate, monoethanolamine, diethylamine, morpholine, dicyandiamide or oxalic acid or mixtures thereof. These additives are generally heat-degradable and gas-liberating at a temperature of from 80"C to 1200C when in the presence of the coating material to liberate a gas, such as ammonia, carbon dioxide or water vapour. Dicyandiamide is not a preferred expanding agent because it is more expensive than urea.

The coating material can also contain compatible additives, when desired, such as fillers, e.g., diatomaceous earth; vermiculite; inorganic or organic fine particles and microspheres which may be heat-expandable; colorants; water repellants; and powdered metal or metallic oxides (e.g., MgO, Awl203).

For conditions where water resistance is desired or required, the ingredients of the coating material or the additive may be selected for this purpose, and still provide the desired flameproofing or fireproofing characteristics with the accompanying increased intumescence. For example, it has been found that resorcinol in the coating material adds to the water-insoluble properties of the coating material. Also, lower phosphoric acid content is beneficial to waterinsolubility, but sufficient phosphoric acid must be present in an amount to produce the desired coating material.

The coating material is usually prepared by blending together the liquid resin former with the liquid hardener at ambient temperature or at a slightly elevated temperature, e.g., 380C, if necessary to lower the viscosity of the blend and thereby facilitate blending. The optional and preferred expanding agent and/or additives can be dissolved in the liquid resin former or added before, during or after the liquid resin former has been blended together with the liquid hardener therefor.

The coating material may be applied to the fire unstable material by any suitable coating method, such as, spray coating, dip or immersion coating or roll coating, at room temperature or higher.

If the fire unstable material is in the form of a sheet or stratum, it may be coated on one or both sides, and if desired, may be provided with a facing material, which preferably is also a flameproof material. A fireproof structural element in the form of a panel may also be produced by laminating a plurality of layers or strata of fire-unstable material with some or all strata having a film of the fireproof intumescent coating material. Many of the coating materials embodying the present invention have adhesive properties which securely adhere together the layers into a laminated structure. When adhesives are used in addition to the coating material, they are preferably at least fire-retarding so that they do not detract from the flameproof and fireproof properties of the laminated panel.If desired, the layers or strata may be laminated in the presence of heat which may also serve to cure the coating material.

In the case of particles of fire-unstable material, such as thermoplastic particles, polystyrene beads, expandable polystyrene beads, or partially expanded expandable polystyrene beads, the particles may be mixed with the coating material and formed into a sheet or panel, desirably in a suitable mould. The mould may then be heated to cure the coating material and, in the case of expandable polystyrene, the heat may also fuse or agglomerate the polystyrene particles into a solid mass.

Suitable heat methods are convection or radiation using various sources of heat. Electronic heating is a desirable method. RF moulding is a known form of heat used in the moulding of polystyrene foam panels and may employ di-electric or radio frequency currents at low or high frequencies. Heat from a microwave oven is also an available method for producing useful sheets or panels containing both the fire-unstable material and fireproof coating material. In the case of expandable or partially expandable polystyrene particles which have been mixed with a flameproof coating material, the combination may be moulded into a panel in a suitable mould by steam or hot air. The heat will cause the polystyrene particles to fuse together, and may, in addition, cause a chemical reaction in the coating material, such as, curing thereof.

As used in the present invention, RF heating is advantageous because the coating materials embodying the present invention have a high power loss factor and may be rapidly cured, together with provision of the adhesive action between the fireproof coating material and the fire-unstable material. When the coating material is mixed with expandable or partially expanded polystyrene particles and heated in a panel mould, the RF heat cures the coating material, adheres it to the polystyrene particles and, in addition, causes fusing or agglomeration of the polystyrene particles into a structural board or panel having good strength and insulating properties, together with the desired fireproof and flameproof properties. If required or desired, the coating material may be slightly varied to achieve the desired response to the electronic current involved.

The flameproof and fireproof products of the invention prepared in accordance with the above procedures will be further illustrated by the following representative Examples. In all the examples of this invention, intumescence began at from 75 to 1500C.

Example 1 In a modified Bureau of Mines Burn Through Test on Dylite M-57A expanded polystyrene, a 12"x12"xl" composite moulded sample [See Footnote (a) in Table IV hereinafter] was supported, on a tripod; the sample was 2" over the tip of a Fisher Burner. The flame of the Fisher Burner was adjusted to 4 1/2" height with a 1 1/2" inner cone. A Kem-Wipe was placed on the top of the sample which was then placed over the flame. Burn through time was indicated by ignition of the Kem Wipe. A five minute (300 seconds) maximum exposure time was adopted.

The data generated from this test are presented in Table III below.

TABLE III Modified Bureau of Mines Burn Through Test Resin Weight Weight Ratio of Time to Former Hardener Ratio Coating MateriaV Burn Through Run No. (RF) (H) of RF/H Dylite (Sec.) Comment Control Nil Nil Nil Nil 5 M-57A; 1.0 pcf Density 1 RF-3 H-4 1/2 2/1 190 2 RF-2 H-6 1/2 2/1 300 No burn through 3 RF-2 H-6 1/1 2/1 300 No burn through 4 RF-2 H-6 1/1 1/1 65 - 5 RF-2 H-6 1/2 2/1 300 Faced with Aluminium Foil-no burn through 6 RF-2 H-6 1/2 2/1 300 Dylite was regular grade-no burn through 7 RF-2 H-15 1/1 2/1 300 No burn through 8 RF-2 H-9 1/2 1/1 60 - All of the above tests were with moulded composites.In additional tests, specially prepared two-ply laminates, one inch thick, (made from polystyrene prepuff moulded and fused and then coated so that the coating material serves as a binder between the two plies and as an outer surface coating) also performed well, with no burn through in 300 seconds in the test.

From the data set forth in Table III above, it will be noted that the composite moulded sample of polystyrene beads without any hardened coating material thereon (Control Run) had a low Burn Through Time of only 5 seconds as contrasted with Runs Nos. 1--8 of the invention wherein the composite moulded sample of polystyrene beads containing a variety of hardened coating material thereon had appreciably higher Burn Through Times ranging from 65 seconds to 300 seconds. Since 300 seconds was the maximum exposure time of the tests, there was no burn through at all for Runs 2, 3 and 5-7 during the given exposure time.

Example 2 In this example, the standard Coast Guard Inflammability Test was run on Dylite M-57A and F-64A expanded polystyrene (EPS) in the form of composite moulded samples [See Footnote (a) in Table IV below] with the test results being set forth in Table IV.

TABLE IV Coast Guard Inflammability Test Run No. 1 2 3 4 5 6 7 Coating Material: Resin Former RF-2 RF-2 RF-2 RF-2 RF-2 RF-2 RF-2 Hardener H-9 H-6 H-6 H-6 H-6 H-6 H-6 Monoethanolamine;% 2 2 2 2 2 2 2 Weight Ratio: Resin Former/Hardener 1/2 1/1 1/2 1/2 1/2 1/2 1/2 Dylite EPS; Type M-57A M-57A M-57A M-57A M-57A M-57A F-64A Weight Ratio: Coating Material/ Dylite (a) 1/1 2/1 2/1 1/1 2/1 2/1 2/1 Other - - - Faced with Faced with 2-3 Mil EPS Heat-Sealable Foam Sheet Aluminium Foil Avg. Density; pcf 1.84 2.90 3.08 2.05 3.26 3.60 2.97 Avg. Deviation, # pcf 0.02 0.06 0.07 0.10 0.04 0.06 0.10 Coast Guard Inflammability (b) Avg. Ignition Time (sec.) 143 128 600 600 600 600 243 Avg. Ignition Temp.

( C) 456 469 - - - - 455 Samples Ignited/5 Samples Tested 4 2 0 0 0 0 3 Temperature C at Test End for Samples that did Not Ignite: 510 514 440 426 460 460 470 Footnotes: (a) Moulded part preparation; the resin former and hardener are mixed well together; the resulting coating material is added to Dylite prepuff under agitation by electric mixer; composite is charged to mould; dry heat moulding program is 3-5 minutes at 104 C-121 C; cool is 5 minutes.

(b) Maximum test time=10 min. (600 seconds) In a Control Run on 1.0 pcf Dylite beadboard without any coating material on the expanded polystyrene beads, the beadboard ignited at a low ignition temperature of about 402"C; whereas in Runs 1--7 (5 samples per run) of the invention, most of the expanded polystyrene bead-boards did not ignite at all (26 out of 35 total samples) even though the temperature at the end of the 600 seconds test time ranged from 426"C to 5140C. Moreover the 9 other samples in Runs 1--7 which did ignite had an average ignition temperature appreciably higher than the 402"C ignition temperature for the control sample, namely 455"C to 4690 C.

Example 3 In this example, composite moulded expanded polystyrene beadboard was tested in the standard UL Tunnel Test with the results being set forth in Table V below. The expanded polystyrene was Dylite M-57A having a nominal 1.0 pcf density. The resin former (RF) and hardener (H) were blended together to form the coating material (except in Control Run 7) which was then added to the prepuff blended in Hobard Mixer and moulded in wood molds to form 4" thick panels.

Each of the coating materials below further contained 2% monoethanolamine and 35 /a methanol. In Run 6 the beadboard had an aluminium foil skin.

TABLE V UL Tunnel Test Run No. 1 2 3 4 5 6 7 (Control) Resin Former RF-2 RF-2 RF-2 RF-2 RF-3 RF-2 None Hardener H-6 H-6 H-6 H-9 H-4 H-6 None Weight Ratio: RF/H 1/1 1/2 1/2 1/2 1/1 1/1 - Weight Ratio: Coating MateriaV Dylite 2/1 2/1 1/1 2/1 2/1 2/1 Finished Panels; Density; pcf 3.56 3.43 2.26 3.34 3.54 3.72 1.00 UL Tunnel Test: Flame Spread 43.6 30.8 92.5 53.6 77.5 43.6 15 Fuel Contributed 12.5 0 31.0 5.6 0 9.0 33.6 Smoke Developed 165 210 725 362 669 323 845-1150 From the data in the above Table V for Runs Nos. 1--6 of the invention versus Control Run 7, it is apparent that the products of the invention have a low fuel contribution and low smoke development.It is important to note that during the test, with the exception of the control sample, the material remained in place on the ceiling of the tunnel with no evidence of dripping and subsequent ignition of melted polymer on the floor of the tunnel as usually experienced with the control sample. Further, over 50 of each sample survived or endured the test, whereas, in the case of the control sample,90% to 100% of the sample was consumed. This is more remarkable when it is realized that the standard test procedure provides for a 10 minute test in Table V.

Example 4 In this example, the above Modified Bureau of Mines Burn Through Test and the above Coast Guard Inflammability Test were run or; laminates prepared from 1/2" thick polyurethane foam, both with (Run 1) and without (Run 2) a Kraft paper interlayer, using a coating material prepared from a resin former (RF-2) and a hardener (H-15) in a 1:1 weight ratio applied at 50 grams per square ft. loading and compared with a Control Run without the coating material. The test results are given in Table VI below.

TABLE VI Run No. Control 1 2 Modified Bureau of Mines Burn Through Test; Time to Burn Through (sec.) 10 300 300 Comment - No burn No burn through through Coast Guard Inflammability Test: Avg. Ignition Time (sec.) 47 292 372 Avg. Ignition Temp. (OC) 418 491 450 Samples Ignited/S Samples Tested 5 2 2 Temperature "C at Test End for Samples that did Not ignite - 478 460 From the data set forth in Table VI above, it will be noted that the polyurethane foam without any hardened coating material thereon (Control Run) has a low burn through time in the Modified Bureau of Mines Burn through Test of only 10 seconds as contrasted with Runs I and 2 of the invention wherein the polyurethane foam having a hardened coating material thereon had no burn through at the end of the 300 second maximum exposure time. In the Coast Guard Inflammability Test, all five samples in the Control Run on polyurethane foam without a hardened coating material thereon ignited at a low ignition temperature of 418"C at the end of only 47 seconds.In contrast therewith, in Runs land 2 of the invention wherein the polyurethane foam was coated with the coating material, 6 out of the 10 total samples did not ignite at all even though the temperature at the end of the 600 seconds test time ranged from 4600C to 4780C. Moreover, the 4 other samples in Runs I and 2 which did ignite had an average ignition temperature appreciably higher than the 418 C ignition temperature for the control sample, namely 450"C to 4910C.

Example 5 Samples of common plywood were coated with one of three different commercially available intumescent paints or with a typical coating material of the invention and exposed to a Fisher Burner flame for 1 minute. The results of the open flame tests are set forth in Table VII below.

TABLE VII Coating Open Flame Testing Concentration Char Intumescence Wood Type (gms./ft2) Formed Occur Depth Ignited FiretectWT-102 25 Yes Yes < 1/16" Yes Firetect PC-210 16 No No - Yes Ball Chem. G-3232 16 Yes Yes 1/4" No Coating Material (Wt. Ratio of RF-2/H-6=l/l) 30 Yes Yes 1 1/2" No The marked superiority of the coating materials of the invention over the commercially available intumescent paints is quite apparent from the comparative data given in the above Table VII.

Example 6 In another experiment, an extruded polyethylene foam sheet having a lattice geometry was coated with coating material embodying the present invention and air dried. Upon exposure to flame the coating intumesced, closing the lattice openings, and averted polymer degradation and subsequent ignition. Upon removal of the intumescent char, the polyethylene was found to be substantially intact.

The following presents comparative data on the moisture resistance of composite mouldings and laminates of the invention.

Coating materials formed of RF-2 and H-6 at a weight ratio of 1:2 were prepared with the addition of 10% methanol and 2% monoethanolamine. These were mixed with expandable polystyrene particles in weight ratios of coating material to beads of 3:1, 2:1, and 1:1, and were moulded into cylinders approximately 4 inches in diameter and 10 inches long. The mouldings were exposed to an RF high frequency current for a period of 10 seconds producing mouldings with excellent fusion and completely dry. One sample was exposed to microwave heat.

The samples were placed in an enclosure having relative humidity in excess of 80%. All of the samples were exposed to this high humidity for a period of 1,000 hours. Upon examination during and after this exposure, there was no evidence of any disassociation of the samples, or that the humidity had any adverse effect on them except for a slight surface tackiness.

Control samples, after being heated in a circulating air oven, survived the exposure to the high humidity for a period of 24 hours, but had disassociated or crumbled at the end of 96 hours.

Samples of two-ply laminates of one inch bead board were laminated together with a ply of kraft paper therebetween, with a coating material on either side of the kraft paper.

The coating material employed was formed of RF-2 and H-15 in a weight ratio of 1:2 with the addition of 0.5 /" of monoethanolamine.

One set of samples was cured at room temperature for one week and upon exposure to the high humidity enclosure they showed signs of partial delamination after 72 hours and after 144 hours were completely delaminated.

Some of the samples were cured in a hot air circulating oven for 8 hours at 1500C and were then air cured for one week. After 72 hours exposure to the high humidity test they showed partial delamination.

Additional samples were cured in a microwave oven at a 10 second exposure, and after 144 hours in the relatively high humidity showed no signs of delamination.

Similar laminates using a coating material formed of RF-2 and H-6, some with the addition of 0.5% monoethanolamine and 10% methanol and some with 2% monoethanolamine and 10% methanol, were allowed to stand at ambient temperature. Upon exposure to the high humidity they were completely delaminated at the end of 48 hours.

WHAT WE CLAIM IS: 1. A flameproof and fireproof product comprising an article coated with a coating material which is capable of starting intumescing, on exposure to a flame or heat at a temperature of from 75 to 1500C., to form a thermal insulating foam barrier on the article, and the foam barrier is such that it becomes a porous uninflammable char or residue on continued exposure to the flame or heat.

2. A product according to Claim 1 in which the weight ratio of the coating material to the article is from 0.04:1 to 4:1.

3. A product according to Claim 2 in which the weight ratio of the coating material to the article is from 0.4:1 to 2:1.

4. A product according to Claim 3 in which the weight ratio of the coating material to the article is about 1:1.

5. A product according to any preceding claim in which the coating material is a polymeric composition.

6. A product according to any preceding claim in which the coating material is a resinous reaction product of phosphoric acid and a reducing sugar together with a hardener.

7. A product according to any of Claims 1 to 5 in which the coating material comprises the resinous reaction product of a liquid resin former with a liquid hardener composition.

8. A product according to Claim 7 in which the weight ratio of the liquid resin former to the liquid hardener is from 1:10 to 10:1.

9. A product according to Claim 8 in which the weight ratio of the liquid resin former to the liquid hardener is from 1:2 to 6:1.

10. A product according to Claim 9 in which the weight ratio of the liquid resin former to the liquid hardener is about 1:1.

11. A product according to any of Claims 7 to 10 in which the liquid resin former comprises the liquid polymeric product of a heated blend of (i) from 25 to 80 /,, by weight of a reducing sugar; (ii) from 4 to 53% by weight of H3PO4 acid; (iii) from 2 to 20% by weight of at least one fluidifier selected from water and dihydric and polyhydric lower aliphatic alcohols; and (iv) from 0 to 15% by weight of a polyhydric phenol selected from resorcinol, pyrogallol and phloroglucinol.

12. A product according to any of Claims 6 to 11 in which the coating material additionally comprises an expanding agent.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (32)

**WARNING** start of CLMS field may overlap end of DESC **. approximately 4 inches in diameter and 10 inches long. The mouldings were exposed to an RF high frequency current for a period of 10 seconds producing mouldings with excellent fusion and completely dry. One sample was exposed to microwave heat. The samples were placed in an enclosure having relative humidity in excess of 80%. All of the samples were exposed to this high humidity for a period of 1,000 hours. Upon examination during and after this exposure, there was no evidence of any disassociation of the samples, or that the humidity had any adverse effect on them except for a slight surface tackiness. Control samples, after being heated in a circulating air oven, survived the exposure to the high humidity for a period of 24 hours, but had disassociated or crumbled at the end of 96 hours. Samples of two-ply laminates of one inch bead board were laminated together with a ply of kraft paper therebetween, with a coating material on either side of the kraft paper. The coating material employed was formed of RF-2 and H-15 in a weight ratio of 1:2 with the addition of 0.5 /" of monoethanolamine. One set of samples was cured at room temperature for one week and upon exposure to the high humidity enclosure they showed signs of partial delamination after 72 hours and after 144 hours were completely delaminated. Some of the samples were cured in a hot air circulating oven for 8 hours at 1500C and were then air cured for one week. After 72 hours exposure to the high humidity test they showed partial delamination. Additional samples were cured in a microwave oven at a 10 second exposure, and after 144 hours in the relatively high humidity showed no signs of delamination. Similar laminates using a coating material formed of RF-2 and H-6, some with the addition of 0.5% monoethanolamine and 10% methanol and some with 2% monoethanolamine and 10% methanol, were allowed to stand at ambient temperature. Upon exposure to the high humidity they were completely delaminated at the end of 48 hours. WHAT WE CLAIM IS:

1. A flameproof and fireproof product comprising an article coated with a coating material which is capable of starting intumescing, on exposure to a flame or heat at a temperature of from 75 to 1500C., to form a thermal insulating foam barrier on the article, and the foam barrier is such that it becomes a porous uninflammable char or residue on continued exposure to the flame or heat.

2. A product according to Claim 1 in which the weight ratio of the coating material to the article is from 0.04:1 to 4:1.

3. A product according to Claim 2 in which the weight ratio of the coating material to the article is from 0.4:1 to 2:1.

4. A product according to Claim 3 in which the weight ratio of the coating material to the article is about 1:1.

5. A product according to any preceding claim in which the coating material is a polymeric composition.

6. A product according to any preceding claim in which the coating material is a resinous reaction product of phosphoric acid and a reducing sugar together with a hardener.

7. A product according to any of Claims 1 to 5 in which the coating material comprises the resinous reaction product of a liquid resin former with a liquid hardener composition.

8. A product according to Claim 7 in which the weight ratio of the liquid resin former to the liquid hardener is from 1:10 to 10:1.

9. A product according to Claim 8 in which the weight ratio of the liquid resin former to the liquid hardener is from 1:2 to 6:1.

10. A product according to Claim 9 in which the weight ratio of the liquid resin former to the liquid hardener is about 1:1.

11. A product according to any of Claims 7 to 10 in which the liquid resin former comprises the liquid polymeric product of a heated blend of (i) from 25 to 80 /,, by weight of a reducing sugar; (ii) from 4 to 53% by weight of H3PO4 acid; (iii) from 2 to 20% by weight of at least one fluidifier selected from water and dihydric and polyhydric lower aliphatic alcohols; and (iv) from 0 to 15% by weight of a polyhydric phenol selected from resorcinol, pyrogallol and phloroglucinol.

12. A product according to any of Claims 6 to 11 in which the coating material additionally comprises an expanding agent.

13. A product according to Claims 7 to 11 in which the coating material

additionally comprises from 0.02 to 0.3 parts by weight, per part by weight of the liquid resin former, of an expanding agent which is heat-degradable and gasliberating at a temperature of from 80 to 1200C when in the presence of the coating material.

14. A product according to Claim 12 or Claim 13 in which the expanding agent is selected from urea, ammonium phosphate, ammonium sulphate, monoethanolamine, diethylamine, morpholine, dicyandiamide and oxalic acid.

15. A product according to any of Claims 6 to 14 in which the hardener is a liquid composition comprising formaldehyde.

16. A product according to Claim 15 in which the liquid hardener composition additionally comprises urea.

17. A product according to Claim 16 in which the mole ratio of formaldehyde to urea is from 1:1 to 2:1.

18. A product according to any of Claims 15 to 17 in which the liquid hardener composition additionally comprises furfuryl alcohol.

19. A product according to Claim 16 or Claim 17 in which the liquid hardener composition additionally comprises glucose and the mole ratio of urea to glucose is from 6:1 to 2:1.

20. A product according to any of Claims 16, 17 and 19 in which the liquid hardener composition additionally comprises furfuryl alcohol and the mole ratio of urea to furfuryl alcohol is from 1:1 to 9:1.

21. A product according to any preceding claim in which the foam barrier has a foam density of from 0.2 to 2 pounds per cubic foot.

22. A product according to any preceding claim in which the material of the article is fire-unstable.

23. A product according to Claim 22 in which the fire-unstable material is polystyrene.

24. A product according to Claim 23 in which the polystyrene is expanded polystyrene.

25. A product according to Claim 22 in which the fire-unstable material is polyurethane foam.

26. A product according to Claim 22 in which the fire-unstable material is polyethylene foam.

27. A product according to Claim 22 in which the fire-unstable material comprises wood particles.

28. A product according to Claim 22 in which the fire-unstable material comprises glass fibres.

29. A product according to Claim 22 in which the fire-unstable material is cork.

30. A product according to any preceding claim in which the article is in sheet form.

31. A product according to any of Claims 1 to 29 in which the article is in laminate form.

32. A product according to Claim 1 substantially as described in any of the Examples.