Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/18—Fireproof paints including high temperature resistant paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/18—Fireproof paints including high temperature resistant paints
  • C09D5/185—Intumescent paints

Definitions

• This invention relates to coating compositions which impart fire-resistance to surfaces and in particular to water-based, non-halogen-containing intumescent, fire protection coating compositions.
• Fire resistance performance of coating compositions has generally been achieved or enhanced by the incorporation of halogenated materials.
• halogenated materials These types of materials have considerable drawbacks in terms of smoke production and toxicity concerns, relating both to combustion products and also to disposal of the compounds themselves. There is a desire towards the replacement of these flame retardants by zero halogen alternatives.
• halogenated flame retardant coatings A further limitation of the use of halogenated flame retardant coatings is that during combustion they emit large amounts of corrosive smoke. Combustion products of halogen containing materials, in particular HC1 and HBr, contribute significantly to these effects. The corrosivity of smoke is of particular importance in electrical/electronic applications, since a small fire involving halogenated insulation materials may generate sufficient corrosive combustion products to cause widespread damage to other equipment not directly involved in the fire.
• intumescent coatings A limitation of intumescent coatings is that the expanded char produced during fire exposure is of limited strength and durability. Eventually, the char is converted to ash and falls away. This factor limits the degree of protection that may be provided to a substrate. It has now been found that non-halogen intumescent coatings having good char strength and burn through resistance may be obtained by employing the combination of zinc oxide and a particular binder.
• a non-halogen-containing, water-based, intumescent fire protection composition comprising an aqueous ethylene vinyl acetate binary copolymer latex and zinc oxide.
• Coatings derived from the compositions of the invention when dried or "cured", may be used as a surface covering for penetration seals to improve thermal insulation of mineral wool based systems, and as a cable coating to provide a barrier against flame spread.
• the compositions may be applied in a similar manner to paint, e.g., by brushing or spraying.
• the compositions of the invention preferably dry to a white flexible film coating. When heated in a fire, the coating expands by up to twenty times in volume to form a thick insulating layer of fire resistant char. More viscous compositions in accordance with the invention may be extruded through a nozzle and used as intumescent fire barrier caulks, sealants and mastics.
• composition means a sprayable or brushable material.
• Coatings derived from compositions of the invention display excellent fire resistance properties and exhibit low smoke and toxic gas production upon combustion. In particular, a surprisingly high char strength and high burn through resistance is exhibited which is attributable to the presence of the combination of the thylene vinyl acetate binary copolymer (EVA) binder and zinc oxide.
• EVA thylene vinyl acetate binary copolymer
• ethylene vinyl acetate copoly ers as water-based latex binders is known, although grades additionally incorporating vinyl chloride monomer are normally preferred as the halogen content confers additional fire resistance.
• the present invention employs as a binder binary copolymers of ethylene and vinyl acetate, i.e., copolymers that do not contain significant numbers of repeat units that are derived from monomers other than ethylene and vinyl acetate.
• copolymers seldom exist as well-defined "pure" compounds, but rather as statistical mixtures of chains of different lengths in which the monomer repeat units may be distributed in a random or non-random fashion. Impurities in the starting monomers and side reactions during (or after) polymerization can introduce minor amounts of additional functionalities on the chains.
• the EVA latex binder is generally present in an amount such that the EVA provides at least 7.5%, usually from 7.5 to 35%, preferably about 16.5% of the total weight of solids of the composition.
• % weight of solids means the % weight of material in the inventive composition which remains on a substrate as a coating.
• a suitable binder is commercially available under the trade name "Vinnapas" EZ-36 from Wacker. Terpolymers comprising vinyl acetate, ethylene and a further monomer e.g., vinyl chloride, acrylate etc. are not suitable for use in the invention.
• the use of zinc oxide as a filler in polymeric formulations is known; for example, Handbook of Fillers for Plastics, eds .
• Zinc oxide may be used to improve resistance to weathering, and promote hardness, heat stability, and electrical conductivity of polymers.
• Zinc oxide has also been used as a synergist with halogen containing flame retardant materials, e.g., as disclosed by Cullis and Hirschler in pp291 to 293 of The Combustion of Organic Polymers, Oxford University Press (1981) .
• halogen containing flame retardant materials e.g., as disclosed by Cullis and Hirschler in pp291 to 293 of The Combustion of Organic Polymers, Oxford University Press (1981) .
• There as been no disclosure of the use of zinc oxide in a non-halogen EVA latex based intumescent compositions There as been no disclosure of the use of zinc oxide in a non-halogen EVA latex based intumescent compositions .
• the zinc oxide is generally present in an amount of at least 0.15%, usually in the range 0.75 to 7.5% by weight based on the total weight of solids in the composition.
• the preferred range is 1.0 to 3.0%. Higher concentrations may give reduced levels of intumescence. If the zinc oxide is absent or replaced by another material, such as titanium oxide, the char strength and burn through resistance of the coatings derived from the compositions are deleteriously affected.
• compositions additionally comprise an intumescent system, e.g., a spumific, such as melamine, in combination with an acid forming catalyst, such as ammonium polyphosphate, and a carbonific material, such as pentaerythritol .
• an intumescent system e.g., a spumific, such as melamine
• an acid forming catalyst such as ammonium polyphosphate
• a carbonific material such as pentaerythritol
• compositions may further comprise one or more of the following optional additives: pigments, e.g.
• titanium dioxide iron oxides coalescing agents, e.g., white spirit, 2,2,4- trimethyl-1,3-pentanediol
• thickeners e.g., cellulose ether, fumed silica, aqueous acrylic dispersions, reinforcing agents, e.g., talc, a mixture of mica, quartz and chlorite, fungicides, e.g., 2-n-octyl-4-isothiazolin-3-one, polyacrylate, sodium polyphosphate, and pH adjusters, e.g., sodium hydroxide.
• Other materials which are used as additives in water- based paints may also be employed.
• compositions within the invention would be as follows :
• EVA latex 10 to 40 (of aqueous dispersion e.g. , 55% solids)
• Titanium dioxide up to 10
• Zinc oxide 0.5 to 5
• compositions may be mixed in equipment commonly used for the preparation of water- based paints, including planetary mixers and high dispersion mixers.
• compositions of the invention may be applied in the same way as a water-based emulsion paint, e.g., by brushing, roller coating, dipping and spraying to a variety of surfaces, or extruded through the nozzle of a caulk gun.
• the normal applied thickness is in the range of 0.2 to 5 millimeters.
• the fire protection effectiveness of the coating increases with film thickness.
• the compositions may be used to provide a fire resistant seal to mineral wool based electrical and mechanical through penetrations, e.g., cables, cable trays, steel pipes, when used as a coating on the mineral wool board and penetrating items.
• the inventive compositions may also be applied to cables to provide coatings which suppress flame spread.
• the coating will thereby reduce the generation of toxic and corrosive HC1 gas from polyvinylchloride insulated cables.
• the intumescent coating expands many times in a fire to produce a high volume of protecting char and therefore only a thin coating layer needs to be applied to the cables which does not significantly affect the radiation of heat from cables during normal current carrying operation.
• Neatrosol 250GR Hydroxyethylcellulose commercially available from Aqualon UK Ltd, Warrington
• Calgon P/T a sodium polyphosphate glass commercially available from Calgon and formulated as a 10% by weight solution in water
• Pigment Distributor A an ammonium salt of polyacrylate commercially available from BASF AG, Ludwigshafen;
• Vinnapas" EZ-36 an aqueous dispersion of copolymer of vinyl acetate and ethylene commercially available from Wacker-Chemie GmbH, Munchen;
• Vinnapas CEZ-16, an aqueous dispersion of terpolymer of vinyl acetate and ethylene and vinyl chloride commercially available from Wacker-Chemie GmbH, Munchen;
• Vinnapas EAF-60, an aqueous dispersion of terpolymer of vinyl acetate and ethylene and acrylate commercially available from Wacker-Chemie GmbH, Munchen; Pentaerythritol “D/S”, fine ground pentaerythritol commercially available from Degussa AG, Hanau;
• Titanium dioxide "Bayertitan” R-KB-4 commercially available from Bayer AG, Leverkusen,-
• Rohagit SD15 an aqueous dispersion of . acrylic resin based on acrylester and methacrylic acid commercially available from Rohm GmbH, Darmstadt;
• FiberDam 150 a caulk commercially available from Minnesota Mining and Manufacturing Company, Saint Paul, Minnesota.
• Examples 1 to 5 disclose the preparation of intumescent compositions of this invention.
• Examples A to H are comparative examples.
• the fire test performance of the formulations are shown in Examples 14 and 15, and the smoke and toxic gas emission is demonstrated in Example 16.
• compositions of Examples 1 to 5 are detailed in Tables 1 and 2.
• compositions of Examples 1 to 4 were mixed in a planetary mixer with two litre capacity with batch sizes of 1 to 2 kg.
• a planetary mixer known under the trade designation "Kenwood Chef", with a “K” blade mixing head was used. Mixing speeds were varied throughout the blending process to achieve optimum dispersion.
• the ingredients were added to the mixing bowl in the order given in Tables 1 and 2 with continuous mixing. Each material was mixed until thoroughly dispersed before adding the next ingredient . When completely blended, the mixtures were stored in an airtight non-metallic container.
• Example 5 The composition of Example 5 was mixed in a pilot scale 30 kg batch using a mixing vessel with a high speed dispersion blade and a slow orbital scraper blade.
• Examples 1 to 5 of this invention all contained both an EVA latex binder ("Vinnapas" EZ-36) and zinc oxide, and were non-halogen formulations. They contained varying amounts of thickening agents . Example 1 also contained a defoamer. These variations in thickener and defoamer content gave rise to slightly different viscosities and coating characteristics of the compositions produced.
• compositions A-D additionally contained the ingredients of TABLE 4.
• Comparative Example A an EVA binder was used, but zinc oxide was replaced by additional titanium dioxide.
• Comparative Examples B to D contained zinc oxide, but with the EVA binder replaced by a terpolymer latex, which was a polymer of ethylene, vinyl acetate and a third monomer.
• the third monomer was either vinyl chloride ("Vinnapas" CEZ-16, Comparative Example B) or an acrylate ("Vinnapas" EAF-60, Comparative Examples C and D) .
• Example 1 In order to demonstrate the effectiveness of the intumescent coating in a mineral wool board based concrete wall penetration seal, a sample of the Composition of Example 1 was used to coat a penetration seal for large scale fire testing in the wall of a 1 m 3 furnace, following in general the ISO 834 standard. Furnace pressure was set to 13 ⁇ 2 pascal. Penetrating items (all 1 m length) were:
• the dried thickness of coating used for this test was approximately 1 mm on the faces and cut edges of mineral wool, 0.4 mm on cables, and 0.2 mm on cable tray.
• a bead of caulk known under the trade designation "FireDam” 150 from 3M, Saint Paul, Minnesota was applied to work as a cold smoke seal.
• Coating on mineral wool board was also extended 50 mm onto concrete to form a cold smoke seal .
• Thermocouples were located on the mineral wool boards and on the penetrating items at 25 mm from wall surface and 25 mm beyond end of coating.
• Example 14 the levels of emission of smoke and carbon monoxide (CO) produced during combustion of a composition of this invention (non-halogen formulation) were compared with a commercially available intumescent coating which contained chlorine.
• Samples of coatings on aluminum foil were prepared as described in Example 14, using Compositions X of Example 5 and Comparative Example G (Pyrosafe
• Flammoplast KS-1 comparative
• Both materials were examined by energy dispersive X-ray elemental analysis (EDAX) .
• EDAX energy dispersive X-ray elemental analysis
• the coating from Example 12 was found to contain chlorine. No chlorine was seen in the coating from Example 5.
• Example 17 All formations disclosed in previous examples were designed for use as intumescent coatings. In the two formulations shown below, an increased level of Rohagit SD15 thickener was employed to give a higher viscosity material, for a different application. These two formulations have been shown to be suitable for use as a water-based intumescent fire barrier caulk, sealant or mastic.
• the distance that the material flowed down the vertical surface of the block was recorded after five minutes . Smaller measured distances correspond to lower degrees of sag, and a value of 10 mm or less indicates that the material has satisfactory performance as a "non sag" caulk.
• the sample of zinc borate used for these Examples was "Firebrake” ZB fine, United States Borax and Chemical Corporation, Los Angeles.
• formulation 103 containing 2 parts zinc borate produced slightly improved burn through resistance over the other comparative examples studied, the performance was inferior to that obtainable with formulations containing 2 parts zinc oxide.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Paints Or Removers (AREA)
• Fireproofing Substances (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

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• 1993
  • 1993-01-22 GB GB9301271A patent/GB2274459B/en not_active Expired - Fee Related
• 1994
  • 1994-01-18 WO PCT/US1994/000643 patent/WO1994017142A1/en not_active Application Discontinuation
  • 1994-01-18 EP EP94906677A patent/EP0680500A1/de not_active Withdrawn
  • 1994-01-18 KR KR1019950703000A patent/KR960700315A/ko not_active IP Right Cessation

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