WO2024164050A1

WO2024164050A1 - Fire retardant composites

Info

Publication number: WO2024164050A1
Application number: PCT/AU2024/050081
Authority: WO
Inventors: Lei LEI; Hengqi CHEN; Hongyang Li
Original assignee: Flame Security International Pty Ltd
Priority date: 2023-02-09
Filing date: 2024-02-08
Publication date: 2024-08-15

Abstract

Fire retardant particulate compositions comprising polystyrene, copolymers of styrene with unsaturated carboxylic acid and/or unsaturated carboxylic ester, and fire retardant additives are provided, as are foam composites produced from the particulate compositions. The foam composites find use as cladding materials in building and construction and in packaging applications.

Description

Fire Retardant Composites

Field of the disclosure

[0001] The present disclosure relates to fire retardant particulate compositions comprising polystyrene, copolymers of styrene with unsaturated carboxylic acid and/or unsaturated carboxylic ester, and fire retardant additives, and to fire retardant foam composites produced from the fire retardant particulate compositions. The fire retardant foam composites find particular, although not exclusive, use as cladding materials in building and construction.

Background of the disclosure

[0002] Several recent high profile fires around the world have highlighted the use of combustible cladding as a building material.

[0003] Expanded or expandable polystyrene (EPS) is a highly porous (>98 vol.%) foam-like insulating material which outperforms other polymeric and traditional insulation materials due to its lightweight, low-cost, and superior acoustic and thermal insulation properties.

[0004] EPS products have been extensively used in insulation packaging, transportation, and particularly building construction which is the largest EPS end-user application.

[0005] However, many existing EPS products are extremely flammable due to their petrochemical-derived organic skeleton and high air-contact interface area. A small amount of heat or spark may cause EPS combustion, leading to rapid fire spread and structural collapse. Worldwide regulations mandate that fire-retardant must be incorporated into building insulating materials, such as EPS.

[0006] Currently, only two commercialized fire-retardant EPS technologies/products have been developed based on the industry standard EPS manufacturing processes. In one method fire retardant components are incorporated during EPS bead synthesis.

Adding a small amount (0.5-1 wt%) of active halogen-containing fire retardant additives (e.g., hexabromocyclododecane, HBCD) during the production of polystyrene beads enables the obtained EPS product to pass the fire retardant German standard B2 of DIN 4102. However, the European Union has banned halogenated fire retardant chemicals due to them releasing toxic thermal degradation products during combustion.

[0007] Another method is based on surface fire retardant coating of EPS beads. Coating flammable EPS beads with fire retardant resins or adhesives may impart fire resistance while having a minor effect on EPS products’ mechanical, acoustic, and thermal insulation properties. However, using hazardous phenolic or amine-based resins as the fire retardant adhesive may cause the release of toxic formaldehyde during fire retardant treatment and application. Furthermore, this method requires expensive equipment upgrades and maintenance due to the harsh fire retardant treatment and hazardous operating conditions.

[0008] In view of the foregoing there remains a need for alternative fire retardant EPS materials.

[0009] Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and/or combined with other pieces of prior art by a skilled person in the art.

Summary of the disclosure

[0010] In one aspect the present disclosure provides a fire retardant particulate composition comprising coated expandable polystyrene beads, wherein the coating comprises one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomers, and one or more fire retardant additives.

[0011] In embodiments, the unsaturated carboxylic acid comprises one or both of methacrylic acid and acrylic acid.

[0012] In embodiments, the unsaturated carboxylic ester comprises one or both of methacrylic ester and acrylic ester.

[0013] In embodiments, the unsaturated carboxylic ester comprises one or more of alkyl methacrylate and alkyl acrylate, wherein the alkyl group comprises a Ci to C10 linear or branched alkyl. [0014] In embodiments, the unsaturated carboxylic ester comprises one or more of methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and iso-octyl acrylate.

[0015] In embodiments, the copolymer further comprises units derived from one or more diketo acrylamide monomers, such as diacetone acrylamide (DAAM).

[0016] In embodiments, the copolymer may be crosslinked.

[0017] In embodiments, the copolymer is crosslinked via pendant ketone carbonyl moieties.

[0018] Various crosslinking agents known in the art may be utilised, such as, for example, adipic dihydrazide, to form a ketimine crosslinking moiety.

[0019] In embodiments, the copolymer comprises ketimine crosslinking moieties.

[0020] In embodiments, units derived from styrene in the copolymer are from about 60 wt.% to about 95 wt.%, based on the total weight of the copolymer.

[0021] In embodiments, the copolymer has a T_g from about 10°C to about 40°C, or from about 15°C to about 35°C, or from about 20°C to about 35°C.

[0022] In embodiments, the copolymer has a minimum film formation temperature of at least 20°C.

[0023] In embodiments, a 50 wt.% dispersion of the copolymer in water has a dynamic viscosity from about 1000 to about 3000 mPa.s measured at 25°C.

[0024] In embodiments, the expandable polystyrene beads are partially expanded.

[0025] In embodiments, the expandable polystyrene beads have a density from about 10 kg/m³ to about 30 kg/m³.

[0026] In embodiments, the one or more fire retardant additives comprise one or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0027] In embodiments, the polyphosphate comprises one or more of melamine polyphosphate and ammonium polyphosphate. [0028] In embodiments, the inorganic filler comprises one or more of layered aluminosilicate, aluminium trihydrate, magnesium hydroxide, zinc borate, boric acid, limestone, calcium carbonate, sodium bicarbonate, sodium carbonate, alumina, silica, fly ash, iron oxide, and fibre glass.

[0029] In embodiments, the thermally expandable material comprises one or more of expandable graphite and expandable vermiculite.

[0030] In embodiments, the polyhydroxy compound is an organic polyhydroxy compound.

[0031] In embodiments, the polyhydroxy compound comprises one or more of lignin, alkaline lignin, starch, glucose, pentaerythritol, sorbitol, dextrin, tannic acid, and di pentaerythritol.

[0032] In embodiments, the fire retardant particulate composition comprises:

(a) from about 10 wt.% to about 50 wt.% expandable polystyrene beads;

(b) from about 10 wt.% to about 30 wt.% of one or more copolymers; and

(c) from about 30 wt.% to about 70 wt.% of one more fire retardant additives; based on the total weight of the fire retardant particulate composition.

[0033] In embodiments, the copolymer comprises:

(a) from about 60 wt.% to about 95 wt.% of units derived from styrene;

(b) from about 1 wt.% to about 10 wt.% of units derived from unsaturated carboxylic acid; and/or

(c) from about 5 wt.% to about 30 wt.% of units derived from unsaturated carboxylic ester.

[0034] In embodiments, the copolymer further comprises from about 1 to about 5 wt.% of units derived from diketo acrylamide, such as diacetone acrylamide. [0035] In embodiments, the fire retardant particulate composition comprises two or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0036] In embodiments, the fire retardant particulate composition comprises three or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0037] In embodiments, the fire retardant particulate composition comprises each of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0038] In embodiments, the fire retardant particulate composition comprises one or both of ammonium polyphosphate and melamine polyphosphate, one or both of layered aluminosilicate and aluminium trihydrate, one or more of lignin, corn starch, potato starch, tannic acid and pentaerythritol, and expandable graphite.

[0039] In embodiments, the lignin may be an alkaline lignin.

[0040] In embodiments, a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expandable polystyrene in the fire retardant particulate composition is from 1:1 to 5:1.

[0041] In another aspect the present disclosure provides a method of producing the fire retardant particulate composition according to any one of the herein disclosed embodiments comprising the step of combining an aqueous dispersion of copolymer with one or more fire retardant additives and combining the resultant dispersion with expandable polystyrene beads.

[0042] In embodiments, the dispersion is combined with the polystyrene beads in a rotating mixer or fluidised bed.

[0043] The expandable polystyrene beads may be coated using a variety of methods such as fluidized bed coating, electrostatic coating, or spray coating. The coating method may depend on the desired coating thickness and the type of coating material.

[0044] In embodiments, the aqueous dispersion of copolymer and one or more fire retardant additives comprises from about 10 wt.% to about 50 wt.% water. [0045] In embodiments, the aqueous dispersion of copolymer and one or more fire retardant additives comprises one or more rheological additives and/or dispersants, such as xanthan gum.

[0046] In embodiments, up to about 1 wt.% of one or more rheological additives and/or dispersants may be present in the aqueous dispersion of copolymer and one or more fire retardant additives, based on the total weight of copolymer, one or more fire retardant additives, and water.

[0047] In another aspect, the present disclosure provides an aqueous dispersion of one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomers, and one or more fire retardant additives.

[0048] The aqueous dispersion may further comprise one or more rheological additives and/or dispersants, such as xanthan gum.

[0049] In another aspect the present disclosure provides a fire retardant foam composite comprising coated expanded polystyrene beads, wherein the coating comprises one or more monomers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomers, and one or more fire retardant additives.

[0050] The composition of the fire retardant foam composite may be according to any one of the herein disclosed embodiments in reference to the particulate fire retardant composition.

[0051] In embodiments, the density of the fire retardant foam composite is greater than 20 kg/m³.

[0052] In embodiments, the limiting oxygen index of the fire retardant foam composite is greater than 20%, as determined according to ASTM D2863-97.

[0053] In embodiments, the peak heat release rate of the fire retardant foam composite is less than 200 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354. [0054] In another aspect the present disclosure provides a method of producing the fire retardant foam composite according to any one of the herein disclosed embodiments comprising the step of molding the fire retardant particulate composition according to any one of the herein disclosed embodiments in the presence of steam.

[0055] In another aspect the present disclosure provides a composite block, panel or sheet comprising the fire retardant foam composite according to any one of the herein disclosed embodiments.

[0056] In another aspect the present disclosure provides use of the composite block, panel or sheet in building or construction.

[0057] In another aspect the present disclosure provides a surface coated fire retardant foam composite comprising the fire retardant foam composite according to any one of the herein disclosed embodiments coated on one or more surfaces with a fire retardant surface coating.

[0058] In embodiments, the fire retardant surface coating comprises one or more polymeric binders and one or more fire retardant additives.

[0059] The one or more polymeric binders comprise one or more of:

• copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomer, including crosslinked copolymers thereof;

• copolymers of ethylene and vinyl esters;

• acrylic modified polydialkylsiloxanes, such as polydimethylsiloxanes.

[0060] The one or more fire retardant additives comprise one or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0061] Preferably, the one or more fire retardant additives comprise one or more of polyphosphate, thermally expandable materials, and polyhydroxy compounds.

[0062] In embodiments, the thickness of the fire retardant surface coating is from about 0.1 mm to about 2 mm, preferably from about 0.1 mm to about 1 mm. [0063] The fire retardant surface coating may be applied as an aqueous dispersion to the fire retardant foam composite by brushing or spraying.

[0064] In embodiments, the aqueous dispersion of the fire retardant surface coating comprises from about 10 wt.% to about 50 wt.% water.

[0065] In embodiments, the aqueous dispersion of fire retardant surface coating comprises one or more rheological additives, dispersants, and defoaming agents. Examples of rheological additives, dispersants, and defoaming agents include salts of polyacrylic acid

[0066] In embodiments, up to about 1 wt.% of one or more rheological additives, dispersants, and defoaming agents may be present in the aqueous dispersion of fire retardant surface coating, based on the total weight of fire retardant surface coating components and water.

[0067] In another aspect the present disclosure provides an aqueous dispersion of the fire retardant surface coating according to any one of the herein disclosed embodiments.

[0068] In embodiments, the aqueous dispersion may comprise one or more rheological additives, dispersants, and defoaming agents.

[0069] In another aspect the present disclosure provides a fire retardant surface coating comprising one or more polymeric binders and one or more fire retardant additives.

[0070] Advantages of the present compositions, composites, or surface coated composites include one or more of the following:

• high limiting oxygen index;

• low toxic gas production on combustion;

• low mass loss rate on combustion;

• straightforward to manufacture; non-hazardous materials which are VOC free and non-corrosive; and • excellent foam composite structural integrity.

[0071] Any embodiment herein shall be taken to apply mutatis mutandis to any other embodiment unless specifically stated otherwise.

[0072] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purpose of exemplification only. Functionally-equivalent products, compositions and processes are clearly within the scope of the disclosure, as described herein.

[0073] Further aspects of the present disclosure and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.

Brief description of the drawings

[0074] Figure 1 contains photographs of foam composites after being subjected to a torch flame test.

Detailed description of the embodiments

[0075] It will be understood that the disclosure described and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the disclosure.

Definitions

[0076] For purposes of interpreting this specification, terms used in the singular will also include the plural and vice versa.

[0077] As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps.

[0078] "About" as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20% or ±10%, in some instances ±5%, in some instances ±1%, and in some instances ±0.1% from the specified value, as such variations are appropriate to perform the disclosed methods.

[0079] Ranges: throughout this disclosure, various aspects of the disclosure can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range.

[0080] The present disclosure relates to fire retardant particulate compositions comprising coated expandable polystyrene beads, wherein the coating comprises one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomer, and one or more fire retardant additives.

[0081] The disclosure also relates to fire retardant foam composites derived from the particulate compositions.

[0082] A feature of the presently disclosed fire retardant particulate compositions and fire retardant foam composites is the use of a copolymer based coating which is compatible with the polystyrene beads. The copolymer serves as an adhesive to bind the fire retardant additives to the polystyrene.

Fire retardant particulate compositions

[0083] The fire retardant particulate compositions comprise coated expandable polystyrene beads, wherein the coating comprises one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomer, and one or more fire retardant additives. Expandable polystyrene beads

[0084] The expandable polystyrene beads suitable for preparing the fire retardant particulate compositions are those typically used for the manufacture of expanded polystyrene foams.

[0085] In embodiments, the expandable polystyrene beads are partially expanded.

[0086] In embodiments, the expandable polystyrene beads have a density from about 10 kg/m³ to about 30 kg/m³. Higher or lower density expandable polystyrene beads may also be utilsed.

[0087] In embodiments, the amount of expandable polystyrene beads in the fire retardant particulate composition is from about 10 wt.% to about 50 wt.%, based on the total weight of the fire retardant particulate composition, or from about 15 wt.% to about 50 wt.%, or from about 20 wt.% to about 50 wt.%, or from about 25 wt.% to about 50 wt.%, or from about 15 wt.% to about 45 wt.%, or from about 15 wt.% to about 40 wt.%, or from about 20 wt.% to about 45 wt.%, or from about 25 wt.% to about 40 wt.%, or from about 25 wt.% to about 45 wt.%.

[0088] In embodiments, the amount of expandable polystyrene beads in the fire retardant particulate composition is about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 20 wt.%, or about 31 wt.%, or about 32 wt.%, or about 33 wt.%, or about 34 wt.%, or about 35 wt.%, or about 36 wt.%, or about 37 wt.%, or about 38 wt.%, or about 39 wt.%, or about 40 wt.%, or about 41 wt.%, or about 42 wt.%, or about 43 wt.%, or about 44 wt.%, or about 45 wt.%, or about 46 wt.%, or about 47 wt.%, or about 48 wt.%, or about 49 wt.%, or about 50 wt.%, based on the total weight of the fire retardant particulate composition.

Copolymer

[0089] The copolymer of the present disclosure are copolymers of styrene with unsaturated carboxylic acid and/or unsaturated carboxylic ester. [0090] The copolymer may serve as a binder for the one or more fire retardant additives and, due to the styrene content, may additionally provide adhesion and compatibility with the expandable polystyrene beads. The copolymers, being water based, may be free of volatile organic components and are typically pH neutral or close to pH neutral. The non-corrosive nature of the copolymers is advantageous in terms of equipment maintenance.

[0091] A wide range of copolymers of styrene with unsaturated carboxylic acid and/or unsaturated carboxylic ester may be utilised as binders for the presently disclosed fire retardant particulate compositions and subsequently derived fire retardant foam composites.

[0092] In embodiments, the copolymers comprise styrene, unsaturated carboxylic acid and unsaturated carboxylic esters.

[0093] In embodiments, the copolymers comprise styrene and unsaturated carboxylic acid.

[0094] In embodiments, the copolymers comprise styrene, a single unsaturated carboxylic acid and one or more unsaturated carboxylic esters.

[0095] In embodiments, the unsaturated carboxylic acid comprises one or both of methacrylic acid and acrylic acid.

[0096] In embodiments, the copolymers comprise styrene and unsaturated carboxylic ester.

[0097] In embodiments, the unsaturated carboxylic ester comprises one or both of methacrylic ester and acrylic ester.

[0098] In embodiments, the unsaturated carboxylic ester comprises one or more of alkyl methacrylate and alkyl acrylate, wherein the alkyl group comprises a Ci to C10 linear or branched alkyl.

[0099] In embodiments, the unsaturated carboxylic ester comprises one or more of methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-butyl acrylate, ethylhexyl acrylate, and iso-octyl acrylate. [0100] In embodiments, the copolymer further comprises units derived from one or more diketo acrylamide monomers, such as diacetone acrylamide (DAAM).

[0101] In embodiments, the copolymer may be crosslinked.

[0102] In embodiments, the copolymer is crosslinked via pendant ketone carbonyl moieties.

[0103] Various crosslinkers known in the art may be utilised, such as, for example, adipic dihydrazide, to form a ketimine crosslinking moiety.

[0104] In embodiments, the copolymer has a T_g from about 10°C to about 40°C, or from about 15°C to about 35°C, or from about 20°C to about 35°C.

[0105] In embodiments, the copolymer has a minimum film formation temperature of at least 20°C.

[0106] In embodiments, units derived from styrene in the copolymer are from about 60 wt.% to about 95 wt.%, based on the total weight of the copolymer.

[0107] In embodiments, units derived from unsaturated carboxylic acid are from about 1 wt.% to about 10 wt.%, based on the total weight of the copolymer.

[0108] In embodiments, units derived from unsaturated carboxylic ester are from about 5 wt.% to about 30 wt.%, based on the total weight of the copolymer.

[0109] In embodiments, the copolymer further comprises from about 1 to about 5 wt.% of units derived from diketo acrylamide, such as diacetone acrylamide.

[0110] In embodiments, a 50 wt.% dispersion of the copolymer in water has a dynamic viscosity from about 1000 to about 3000 mPa.s measured at 25°C.

[0111] In embodiments, the amount of copolymer in the fire retardant particulate composition is from about 10 wt.% to about 30 wt.%, based on the total weight of the fire retardant particulate composition, or from about 11 wt.% to about 30 wt.%, from about 12 wt.% to about 30 wt.%, from about 13 wt.% to about 30 wt.%, from about 14 wt.% to about 30 wt.%, from about 15 wt.% to about 30 wt.%, from about 10 wt.% to about 29 wt.%, from about 10 wt.% to about 28 wt.%, from about 10 wt.% to about 27 wt.%, from about 10 wt.% to about 26 wt.%, from about 10 wt.% to about 25 wt.%, from about 10 wt.% to about 24 wt.%, from about 10 wt.% to about 23 wt.%, from about 10 wt.% to about 22 wt.%, from about 10 wt.% to about 21 wt.%, from about 10 wt.% to about 20 wt.%, or from about 15 wt.% to about 25 wt.%.

[0112] In embodiments, the amount of copolymer in the fire retardant particulate composition is about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, based on the total weight of the fire retardant particulate composition.

Preparation of copolymer

[0113] Copolymers suitable for use in preparing the presently disclosed fire retardant particulate compositions may be synthesised using well know surfactant free emulsion polymerization techniques.

[0114] A preferred copolymer is one comprising diketo acrylamide monomer units that are crosslinkable via keto-hydrazide crosslinking.

[0115] In embodiments, the mechanism of crosslinking relies on a self-crosslinking reaction involving, for example, diacetone acrylamide (DAAM) and adipic acid dihydrazide (ADH).

[0116] The self-crosslinking process of DAAM and ADH is enabled by incorporating DAAM monomer into the copolymer. The concentration of DAAM may be approximately 1-5 wt.% of the overall monomer mixture.

[0117] In embodiments, DAAM monomers may uniformly integrated with the acrylic, styrene, and other comonomers during the synthesis of the copolymer. This integration results in the creation of well-dispersed latex particles comprising pendant ketone crosslinking sites. Subsequently, ADH may be dissolved within the water-based latex dispersion. This enables the emulsion copolymer to become cross-linkable via the pendant ketone carbonyl moiety. [0118] Typically, the emulsion is neutralized with ammonia, and adipic acid dihydrazide (ADH) is then added to the emulsion as an aqueous solution. The ratio of DAAM to ADH is typically 2.1 to 1.0.

[0119] The water containing acrylic-styrene emulsion based on DAAM/ADH in the aqueous phase are initially non-reactive, however on removing water and evaporation of ammonia, coalescence of the film occurs, and the pH decreases, becoming acidic. As the pH decreases, the crosslinking reaction rate begins to increase with the formation of a ketimine moiety between the DAAM and the ADH.

[0120] In embodiments, the DAAM/ADH crosslinking occurs post-coalescence, allowing good molecular inter-diffusion between emulsion particles as the film dries, which enhances film properties.

Fire retardant additives

[0121] In embodiments, the one or more fire retardant additives comprise one or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

Polyphosphates

[0122] In embodiments, the polyphosphate comprises one or more of melamine polyphosphate and ammonium polyphosphate.

[0123] In embodiments, the ammonium polyphosphate is ammonium polyphosphate (Type II).

[0124] In embodiments, the one or more ammonium polyphosphates may have a solubility in water of less than 1 wt.% at 20°C, or less than 0.5 wt.% at 20°C.

[0125] In embodiments, the one or more ammonium polyphosphates comprise a particulate polyphosphate having an average particle size (D50) of 5 to 50 micron, preferably 10 to 30 micron. The average particle size may be determined by, for example, laser diffraction.

[0126] The amount of polyphosphate fire retardant in the fire retardant particulate composition is from about 5 wt.% to about 30 wt.%, or from about 5 wt.% to about 25 wt.%, from about 5 wt.% to about 20 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 25 wt.%, from about 10 wt.% to about 20 wt.%, based on the total weight of the fire retardant particulate composition.

[0127] In embodiments, the amount of polyphosphate fire retardant in the fire retardant particulate composition is about 5 wt.%, or about 6 wt.%, or about 7 wt.%, or about 8 wt.%, or about 9 wt.%, or about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, based on the total weight of the fire retardant particulate composition.

Inorganic fillers

[0128] In embodiments, non-limiting examples of inorganic fillers comprises one or more inorganic fillers such as one or more of layered aluminosilicate, aluminium trihydrate, magnesium hydroxide, zinc borate, boric acid, limestone, calcium carbonate, sodium bicarbonate, sodium carbonate, alumina, silica, fly ash, iron oxide, and fibre glass.

[0129] In some embodiments, a preferred inorganic filler is layered aluminosilicate.

[0130] In embodiments, the amount of inorganic filler in the presently disclosed fire retardant particulate composition is from about 2 wt.% to about 30 wt.%, from about 3 wt.% to about 30 wt.%, from about 4 wt.% to about 30 wt.%, from about 5 wt.% to about 30 wt.%, from about 2 wt.% to about 25 wt.%, from about 2 wt.% to about 20 wt.%, from about 2 wt.% to about 15 wt.%, from about 3 wt.% to about 15 wt.%, from about 4 wt.% to about 15 wt.%, based on the total weight of the fire retardant particulate composition.

[0131] In embodiments, the amount of inorganic filler in the presently disclosed fire retardant particulate composition is about 2 wt.%, or about 3 wt.%, or about 4 wt.%, or about 5 wt.%, or about 6 wt.%, or about 7 wt.%, or about 8 wt.%, or about 9 wt.%, or about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, based on the total weight of the fire retardant particulate composition.

Thermally expandable material

[0132] In embodiments, the thermally expandable material comprises one or more of expandable graphite and expandable vermiculite.

[0133] Expandable graphites are graphites in which the interstitial layers contain foreign groups (for example sulphuric acid) which lead to thermal expansion. They include nitrosated, oxidised and halogenated graphites. The expandable graphite expands when in a temperature range of from 80°C to 250°C or more, expanding the composition so that it forms an insulating char layer on the substrate.

[0134] In embodiments, the amount of thermally expandable material in the presently disclosed fire retardant particulate composition is from about 5 wt.% to about 25 wt.%, or from about 5 wt.% to about 20 wt.%, or from about 10 wt.% to about 20 wt.%, based on the total weight of the fire retardant particulate composition.

In embodiments, the amount of thermally expandable material in the presently disclosed fire retardant particulate composition is about 5 wt.%, or about 6 wt.%, or about 7 wt.%, or about 8 wt.%, or about 9 wt.%, or about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, based on the total weight of the fire retardant particulate composition.

Polyhydroxy compound

[0135] In embodiments, the polyhydroxy compound is an organic polyhydroxy compound.

[0136] In embodiments, the polyhydroxy compound comprises one or more of lignin, starch, glucose, pentaerythritol, sorbitol, dextrin, tannic acid, and dipentaerythritol. Other polyhydroxy compounds are contemplated.

[0137] In embodiments, the polyhydroxy compound comprises one or more of lignin, corn starch and potato starch. [0138] In embodiments, the amount of polyhydroxy compound in the presently disclosed fire retardant particulate composition is from about 2 wt.% to about 20 wt.%, or from about 3 wt.% to about 20 wt.%, or from about 4 wt.% to about 20 wt.%, or from about 5 wt.% to about 20 wt.%, or from about 2 wt.% to about 15 wt.%, or from about 3 wt.% to about 15 wt.%, or from about 4 wt.% to about 15 wt.%, or from about 5 wt.% to about 15 wt.%, based on the total weight of the fire retardant particulate composition.

[0139] In embodiments, the amount of polyhydroxy compound in the presently disclosed fire retardant particulate composition is about 2 wt.%, or about 3 wt.%, or about 4 wt.%, or about 5 wt.%, or about 6 wt.%, or about 7 wt.%, or about 8 wt.%, or about 9 wt.%, or about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, based on the total weight of the fire retardant particulate composition.

[0140] In some preferred embodiments, the fire retardant particulate composition comprises two or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0141] In some preferred embodiments, the fire retardant particulate composition comprises three or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0142] In some particularly preferred embodiments, the fire retardant particulate composition comprises each of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0143] In some particularly preferred embodiments, the fire retardant particulate composition comprises one or both of ammonium polyphosphate and melamine polyphosphate, one or both of layered aluminosilicate and aluminium trihydrate, one or both of lignin, pentaerythritol, corn starch and potato starch, and expandable graphite.

[0144] In embodiments, the fire retardant particulate composition comprises:

(a) from about 10 wt.% to about 50 wt.% expandable polystyrene beads;

(b) from about 10 wt.% to about 30 wt.% of one or more copolymers; and (c) from about 30 wt.% to about 70 wt.% of one more fire retardant additives; based on the total weight of the fire retardant particulate composition.

[0145] In embodiments, the fire retardant particulate composition comprises:

(a) from about 25 wt.% to about 45 wt.% of expandable polystyrene beads;

(b) from about 15 wt.% to about 25 wt.% of one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomers;

(c) from about 10 wt.% to about 20 wt.% of one or both of ammonium polyphosphate and melamine polyphosphate;

(d) from about 10 wt.% to about 20 wt.% of expandable graphite;

(e) from about 2 wt.% to about 15 wt.% of layered aluminosilicate; and

(f) from about 2 wt.% to about 15 wt.% of polyhydroxy compounds; based on the total weight of the fire retardant particulate composition.

[0146] In any one of the herein disclosed embodiments, a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expandable polystyrene is from 1 :1 to 5: 1 , or from 1 : 1 to 4: 1 , or from 1 : 1 to 3: 1 , or from 1.5:1 to 5: 1 , or from 1.5: 1 to 4: 1 , or from 1.5:1 to 3: 1.

[0147] In any one of the herein disclosed embodiments, a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expandable polystyrene is 1 :1, or 1.5:1 , or 2:1, or 2.5:1 , or 3:1, or 3.5:1 , or 4:1.

[0148] In any one of the herein disclosed embodiments, the lignin may be an alkaline lignin.

[0149] In any one of the herein disclosed embodiments, the layered aluminosilicate may be kaolin. Preparation of fire retardant particulate compositions

[0150] The fire retardant particulate compositions of the present disclosure may be prepared by combining an aqueous dispersion of copolymer with one or more fire retardant additives and combining the resultant dispersion with expandable polystyrene beads.

[0151] In embodiments, the dispersion is combined with the polystyrene beads in a rotating mixer or fluidised bed. Other methods may be utilised.

[0152] In embodiments, the aqueous dispersion of copolymer and one or more fire retardant additives comprises from about 10 wt.% to about 50 wt.% water.

[0153] In embodiments, the aqueous dispersion of copolymer and one or more fire retardant additives comprises one or more rheological additives and/or dispersants, such as xanthan gum.

[0154] In embodiments, up to about 1 wt.%, or up to about 0.5 wt.%, or up to about 0.1 wt.%, of one or more rheological additives and/or dispersants may be present in the aqueous dispersion of copolymer and one or more fire retardant additives, based on the total weight of copolymer, one or more fire retardant additives, and water.

[0155] The one or more rheological additives and/or dispersants may inhibit water separation in the aqueous dispersion and/or sediment formation and extend useful shelve life.

Preparation of fire retardant foam composites

[0156] The fire retardant composites of the present disclosure may be prepared from the presently disclosed fire retardant particulate compositions using existing equipment for producing expanded polystyrene foam. For example the foam composites may be produced in a steam block molder.

Fire retardant foam composites

[0157] In embodiments, the density of the fire retardant foam composite is greater than 20 kg/m³, or greater than 25 kg/m³, or greater than 30 kg/m³, or greater than 35 kg/m³, or greater than 40 kg/m³, or greater than 45 kg/m³, or greater than 50 kg/m³, or greater than 55 kg/m³. [0158] In embodiments, the density of the fire retardant foam composite is from about 20 kg/m³ to about 80 kg/m³, or from about 25 kg/m³ to about 80 kg/m³ or from about 30 kg/m³ to about 80 kg/m³ or from about 35 kg/m³ to about 80 kg/m³ or from about 40 kg/m³ to about 80 kg/m³ or from about 45 kg/m³ to about 80 kg/m³or from about 50 kg/m³ to about 80 kg/m³, or from about 55 kg/m³ to about 80 kg/m³.

[0159] Generally the compositions of the fire retardant foam composites are similar to that of the fire retardant particulate compositions from which they are derived.

[0160] In embodiments, the fire retardant foam composite comprises:

(a) from about 10 wt.% to about 50 wt.% expanded polystyrene beads;

(b) from about 10 wt.% to about 30 wt.% of one or more copolymers; and

(c) from about 30 wt.% to about 70 wt.% of one more fire retardant additives; based on the total weight of the fire retardant foam composite.

[0161] In embodiments, the fire retardant foam composite comprises:

(a) from about 25 wt.% to about 45 wt.% of expanded polystyrene beads;

(d) from about 10 wt.% to about 20 wt.% of expandable graphite;

(e) from about 2 wt.% to about 15 wt.% of layered aluminosilicate; and

(f) from about 2 wt.% to about 15 wt.% of polyhydroxy compounds; based on the total weight of the fire retardant foam composite. Fire retardant behaviour of the fire retardant foam composites

[0162] The presently disclosed fire retardant foam composites demonstrate desirable fire retardant properties.

[0163] In embodiments, the limiting oxygen index, determined according to ASTM D2863-97, is greater than 20%, or greater than 21%, or greater than 22%, or greater than 23%, or greater than 24%, or greater than 25%, or greater than 26%, or greater than 27%, or greater than 28%, or greater than 29%, or greater than 30%.

[0164] In some preferred embodiments, the limiting oxygen index, determined according to ASTM D2863-97, is greater than 27%

[0165] In embodiments, the peak heat release rate of the foam composite is less than 200 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354.

[0166] In embodiments, the peak heat release rate of the foam composite is less than 190 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354, or less than 180 kW/m², or less than 170 kW/m².

Use of fire retardant foam composites

[0167] The fire retardant foam composites of the present disclosure may find a wide range of application and use.

[0168] For example, the fire retardant foam composites may be used in construction and building, such as in claddings for commercial or residential buildings. They may also find use in packaging applications.

Coated fire retardant foam composites

[0169] The present disclosure also provides a surface coated fire retardant foam composite comprising the fire retardant foam composite according to any one of the herein disclosed embodiments coated on one or more surfaces with a fire retardant coating.

[0170] In embodiments, the fire retardant surface coating comprises one or more polymeric binders and one or more fire retardant additives. [0171] The one or more polymeric binders may comprise one or more of:

• copolymers of ethylene and vinyl esters;

• acrylic modified polydialkylsiloxanes, such as polydimethylsiloxane.

[0172] The one or more fire retardant additives may comprise one or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

[0173] Preferably, the one or more fire retardant additives may comprise one or more of polyphosphate, thermally expandable materials, and polyhydroxy compounds.

[0174] In embodiments, the thickness of the fire retardant surface coating is from about 0.1 mm to about 2 mm, preferably from about 0.1 mm to about 1 mm.

[0175] The fire retardant surface coating may be applied as an aqueous dispersion to a surface of the fire retardant foam composite by brushing or spraying.

[0176] In embodiments, the aqueous dispersion of the fire retardant surface coating comprises from about 10 wt.% to about 50 wt.% water.

[0177] In embodiments, the aqueous dispersion of fire retardant surface coating comprises one or more rheological additives, dispersants, and defoaming agents.

[0178] In embodiments, up to about 1 wt.%, or up to about 0.5 wt.%, or up to about 0.1 wt.% of one or more rheological additives, dispersants, and defoaming agents may be present in the aqueous dispersion of fire retardant surface coating, based on the total weight of fire retardant surface coating components and water.

[0179] The one or more rheological additives, dispersants, and defoaming agents may inhibit water separation in the aqueous dispersion and/or sediment formation and extend useful shelve life.

[0180] In embodiments, the fire retardant surface coating comprises: (a) from about 10 wt.% to about 40 wt.% of one or more polymeric binders;

(b) from about 10 wt.% to about 40 wt.% of one or both of ammonium polyphosphate and melamine polyphosphate;

(c) from about 15 wt.% to about 50 wt.% of thermally expandable materials; and

(d) from about 5 wt.% to about 30 wt.% of one or more polyhydroxy compounds; based on the total weight of the fire retardant surface coating.

[0181] In embodiments, the fire retardant surface coating comprises:

(a) from about 15 wt.% to about 35 wt.% of one or more polymeric binders;

(b) from about 15 wt.% to about 35 wt.% of one or both of ammonium polyphosphate and melamine polyphosphate;

(c) from about 20 wt.% to about 45 wt.% of thermally expandable materials; and

(d) from about 10 wt.% to about 30 wt.% of one or more polyhydroxy compounds; based on the total weight of the fire retardant surface coating.

[0182] In embodiments, the fire retardant surface coating optionally comprises from about 2 wt.% to about 15 wt.% of one or more inorganic fillers, based on the total weight of the fire retardant surface coating.

[0183] In embodiments, the amount of copolymer in the fire retardant surface coating is from about 10 wt.% to about 40 wt.%, based on the total weight of the fire retardant surface coating, or from about 11 wt.% to about 40 wt.%, from about 12 wt.% to about 40 wt.%, from about 13 wt.% to about 40 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 39 wt.%, from about 15 wt.% to about 38 wt.%, from about 15 wt.% to about 37 wt.%, from about 15 wt.% to about 38 wt.%, from about 15 wt.% to about 36 wt.%, from about 15 wt.% to about 35 wt.%, from about 15 wt.% to about 34 wt.%, from about 15 wt.% to about 33 wt.%, from about 15 wt.% to about 32 wt.%, from about 15 wt.% to about 31 wt.%, from about 15 wt.% to about 30 wt.%, or from about 15 wt.% to about 25 wt.%. [0184] In embodiments, the amount of copolymer in the fire retardant surface coating is about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, or about 31 wt.%, or about 32 wt.%, or about 33 wt.%, or about 34 wt.%, or about 35 wt.%, based on the total weight of the fire retardant surface coating.

[0185] In embodiments, the ammonium polyphosphate is ammonium polyphosphate (Type II).

[0186] In embodiments, the one or more ammonium polyphosphates may have a solubility in water of less than 1 wt.% at 20°C, or less than 0.5 wt.% at 20°C.

[0187] In embodiments, the one or more ammonium polyphosphates comprise a particulate polyphosphate having an average particle size (D50) of 5 to 50 micron, preferably 10 to 30 micron. The average particle size may be determined by, for example, laser diffraction.

[0188] The amount of polyphosphate fire retardant in the fire retardant surface coating is from about 10 wt.% to about 40 wt.%, or from about 10 wt.% to about 35 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 25 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 35 wt.%, based on the total weight of the fire retardant surface coating.

[0189] In embodiments, the amount of polyphosphate fire retardant in the fire retardant surface coating is about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, or about 31 wt.%, or about 32 wt.%, or about 33 wt.%, or about 34 wt.%, or about 35 wt.%, based on the total weight of the fire retardant surface coating.

[0190] In embodiments, the thermally expandable material comprises one or more of expandable graphite and expandable vermiculite. [0191] In embodiments, the amount of thermally expandable material in the fire retardant surface coating is from about 15 wt.% to about 45 wt.%, or from about 15 wt.% to about 40 wt.%, or from about 20 wt.% to about 40 wt.%, based on the total weight of the fire retardant surface coating.

[0192] In embodiments, the amount of thermally expandable material in the fire retardant surface coating is about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, or about 31 wt.%, or about 32 wt.%, or about 33 wt.%, or about 34 wt.%, or about 35 wt.%, or about 36 wt.%, or about 37 wt.%, or about 38 wt.%, or about 39 wt.%, or about 40 wt.%, or about 41 wt.%, or about 42 wt.%, or about 43 wt.%, or about 44 wt.%, or about 45 wt.%, based on the total weight of the fire retardant surface coating.

[0193] In embodiments, the polyhydroxy compound comprises one or more of lignin, starch, glucose, pentaerythritol, sorbitol, dextrin, tannic acid, and dipentaerythritol.

[0194] In embodiments, the polyhydroxy compound comprises lignin.

[0195] In embodiments, the amount of polyhydroxy compound in the fire retardant surface coating is from about 5 wt.% to about 30 wt.%, or from about 10 wt.% to about 30 wt.%, or from about 5 wt.% to about 25 wt.%, or from about 10 wt.% to about 25 wt.%, based on the total weight of the fire retardant surface coating.

[0196] In embodiments, the amount of polyhydroxy compound in the fire retardant surface coating is about 5 wt.%, or about 6 wt.%, or about 7 wt.%, or about 8 wt.%, or about 9 wt.%, or about 10 wt.%, or about 11 wt.%, or about 12 wt.%, or about 13 wt.%, or about 14 wt.%, or about 15 wt.%, or about 16 wt.%, or about 17 wt.%, or about 18 wt.%, or about 19 wt.%, or about 20 wt.%, or about 21 wt.%, or about 22 wt.%, or about 23 wt.%, or about 24 wt.%, or about 25 wt.%, or about 26 wt.%, or about 27 wt.%, or about 28 wt.%, or about 29 wt.%, or about 30 wt.%, based on the total weight of the fire retardant surface coating.

[0197] In embodiments, a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expanded polystyrene in the fire retardant composite, not including the surface coating components, is from 1:1 to 5:1, or from 1 :1 to 4:1 , or from 1:1 to 3:1 , or from 1.5:1 to 5:1, or from 1.5:1 to 4:1 , or from 1.5:1 to 3:1, or from 1 :1 to 3: 1. Preferably less than 3: 1.

[0198] In embodiments, a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expanded polystyrene in the fire retardant composite, not including the surface coating components, is 1 :1 , or 1.5:1, or 2:1 , or 2.5:1 , or 3:1 , or 3.5:1, or 4:1.

[0199] A particular feature of the presently disclosed surface coated fire retardant foam composites is that they enable a reduction in the fire retardant additive content of the foam composites, thus reducing cost, but, surprisingly, demonstrate significantly enhanced fire protection, relative to a non-coated fire retardant composite.

[0200] The present disclosure also provides a fire retardant surface coating comprising one or more polymeric binders and one or more fire retardant additives.

[0201] The composition of the fire retardant surface coating is as per disclosed for the surface coating in the surface coated fire retardant foam composite.

Fire retardant behaviour of the surface coated fire retardant foam composites

[0202] The presently disclosed surface coated fire retardant foam composites demonstrate desirable fire retardant properties.

[0203] In embodiments, the limiting oxygen index, determined according to ASTM D2863-97, is greater than 20%, or greater than 21%, or greater than 22%, or greater than 23%, or greater than 24%, or greater than 25%, or greater than 26%, or greater than 27%, or greater than 28%, or greater than 29%, or greater than 30%.

[0204] In some preferred embodiments, the limiting oxygen index, determined according to ASTM D2863-97, is greater than 27%

[0205] In embodiments, the peak heat release rate of the surface coated fire retardant foam composite is less than 200 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354.

[0206] In embodiments, the peak heat release rate of the surface coated fire retardant foam composite is less than 190 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354, or less than 180 kW/m², or less than 170 kW/m².

Use of surface coated fire retardant foam composites

[0207] The surface coated fire retardant foam composites of the present disclosure may find a wide range of application and use.

[0208] For example, the surface coated fire retardant foam composites may be used in construction and building, such as in claddings for commercial or residential buildings. They may also find use in packaging applications.

Examples

Materials

[0209] Expandable polystyrene beads used in the preparation of the fire retardant particulate compositions had a density typically from about 10 kg/m³ to about 30 kg/m³.

[0210] Five different copolymers were examined as polymeric binders for the fire retardant particulate compositions and fire retardant composites.

[0211] XA, a crosslinkable copolymer of acrylate, styrene and DAAM, available as a 50% by weight dispersion in water from Shandong Xinlongyu New Material Technology Vo. Ltd; 3998, a styrene acrylic ester copolymer available as a 50% by weight dispersion in water from Guangdong Haisun New Material Technology Co. Ltd; Hydro Pliolite 211, a styrene acrylic copolymer available as a 50% by weight dispersion in water from Synthomer; HMP-3202, an organic silicon modified styrene acrylic emulsion available as a 50% by weight dispersion in water from Guangdong Haisun New Material Technology Co. Ltd; HMP-S801 silicon acrylic copolymer available as a 40-42% by weight dispersion in water from Guangdong Haisun New Material Technology Co. Ltd.

[0212] Melamine polyphosphate was obtained from Yantai FR Flame Retardant Science & Technology, China.

[0213] Alkaline lignin and kaolin were obtained from Qingdao Principle Chemical New Material Co., Ltd. Example 1 : Evaluation of different copolymer binders

[0214] A slurry was prepared by combining an aqueous dispersion of different copolymers and the fire retardant (FR) additives melamine polyphosphate, kaolin, alkaline lignin, and expandable graphite. Further water was optionally added to adjust the viscosity of the slurry. The slurry was then combined with EPS beads, mixed to coat the beads with the slurry, and then dried to provide particulate fire retardant compositions.

[0215] The effect of different copolymers on the preparation of the compositions and performance of the subsequently formed foam composites (e.g. mechanical strength, water resistance) were evaluated and classified as Average, Good, Very good, Excellent, and Outstanding. Table 1 collects details of the various copolymers and performance evaluation of several prepared formulations.

[0216] The results indicated that the speed of drying of the particulate compositions was influenced by the nature of the binder. Furthermore, if, after drying, there was aggregation of the beads, then these required separation before the subsequent molding operation. While all of the utilised copolymers gave useful performance in terms of degree of aggregation and drying speed, it may be advantageous to utilise a copolymer that minimises aggregation. In this regard the XA copolymer performed best.

[0217] The particulate compositions were molded into foam composites by exposing to steam in a plastic container. Subsequently, the moulding integrity, mechanical strength and water resistance of the resulting foams were assessed (Table 1). It was found that the silicon modified copolymers performed less well in terms of these parameters, however performance with these copolymers was acceptable. Across all parameters evaluated, the crosslinked XA copolymer showed excellent to outstanding performance.

Example 2: Fire performance of foam composites

[0218] A number of foam composites were prepared from particulate compositions comprising EPS beads, XA copolymer (except F151 which was prepared with 3998 copolymer) and various different fire retardant additives and molded as in Example 1. Table 2 collects details of the formulations. BFR/EP refers to the weight ratio of copolymer binder plus fire retardant additives to EPS, and FR/Binder refers to the weight ratio of fire retardant additives to copolymer binder.

[0219] APP refers to ammonium polyphosphate, MPP refers to melamine polyphosphate, ATH refers to aluminium trihydrate, PER refers to pentaerythritol, and EG refers to expandable graphite. Table 3 summarises characterising and performance parameters for the composites and Figure 1 contains photographs of each of the composites after torch burning tests. The test was performed by exposing foam composite to a flame until it ignited and then withdrawing the flame and observing the behaviour.

[0220] The specific density was calculated as the ratio of the density of the fire retardant composite/untreated-EPS.

[0221] The self-extinguishing descriptor refers to whether the sample is automatically extinguished after the torch flame is withdrawn.

[0222] The melting/dripping descriptor refers to the observation of shrinkage of the composite and the formation of molten drops during combustion.

[0223] The charring descriptor refers to the protective carbonization structure formed on the sample surface during combustion.

[0224] Fire penetration refers to the depth of sample carbonization due to flame or high temperature during combustion. The deeper the carbonization layer, the poorer the ablation resistance of the surface sample.

[0225] Formulations prepared with MPP, kaolin, or lignin as the sole fire retardant additive continued to burn after removal of the torch flame and did not self-extinguish. [0226] The formulation (F160) with EG as the sole fire retardant additive generated a large amount of expanded carbonization products during combustion. However, these carbonization products were very loose and scattered with the impact of the flame, which would result in poor insulation and flame protection.

[0227] Formulations F145, F151 , F161, F162, and F163 all gave good results and indicated F145 and F161 to give the best overall performance.

Example 3: Preparation of composites in steam block molder

[0228] Three particulate compositions having the formulations outlined in Table 4 were molded in an industrial steam-chestblock molder to produce foam composites. F151 and F153 were prepared with the 3998 copolymer and F145 with the XA copolymer.

[0229] The densities of the three foam composites were measured and compared to those of a foam prepared from untreated EPS and a phenolic-EPS foam. The phenolic- EPS foam had a phenolic/EPS ratio of about 1/2. Table 5 collects the results.

[0230] The limiting oxygen index (LOI) for the three foam composites the untreated EPS and the phenolic-EPS were determined at room temperature to investigate their fire safety performance. The LOI of samples (150 mm * 10 mm * 10 mm) were determined using an HC-2C oxygen index meter according to ASTM D2863-97. Table 5 collects the results.

[0231] The foam composites of the present disclosure all had higher densities than the untreated EPS foam and the phenolic-EPS foam.

[0232] The higher the LOI value, the less likely the material is to burn in real world applications, i.e., the better the fire resistance performance.

[0233] The untreated EPS foam showed high flammability with a very low LOI value of 17%. It experienced serious shrinkage and melt-dripping issues during combustion.

[0234] The phenolic-EPS foam had an increased LOI value relative to untreated EPS of 27%.

[0235] All three formulations according to the present disclosure performed well with LOI’s values ranging 32 to 34%. It is highlighted that all three formulations were markedly superior to phenolic-EPS.

Example 4: Cone-calorimeter tests

[0236] Cone calorimetry (CO) is one of the most widely used techniques to evaluate the flammability of polymeric materials. The combustion environment in the cone calorimetry test mimics actual fire conditions, thus results from cone calorimetry can assist in evaluating the real fire performance of materials. Herein, cone calorimetry was used to evaluate the flame retardance of the foam samples according to ASTM E1354/ISO 5660-1 standards with specimen dimensions of 100 mm * 100 mm x 30 mm. [0237] The detailed cone calorimetric parameters of the different samples at an incident heat flux of 50 kW/m² are collected in Table 6, including the peak of heat release rate (pHRR), time to peak heat release rate (tp), fire growth rate (FIGRA), total heat release (THR), maximum heat release rate (mHRR), the average mass loss rate (mMLR), and the maximum average of heat release emission (MAHRE) measured during the burning time of the sample.

[0238] The results indicated the following:

Peak of heat release rate (pHRR)

[0239] The untreated EPS foam melted continuously during the test process and the melting droplets accumulated more as the combustion progressed. The untreated sample reached a peak heat release rate (pHRR) value of 740 kW/m².

[0240] The phenolic-EPS sample peaked at a pHRR value of 193 kW/m², while the pHRR value of the three foams according to the present disclosure ranged from 140 kW/m² to 163 kW/m². It was noted that the foams according to the present disclosure did not melt.

Fire Growth Rate (FIGRA)

[0241] The fire growth rate (FIGRA) was calculated using pHRR/tp to assess the fire hazards of the foams. Low FIGRA values indicate delayed time to flashover, which can increase time for evacuation and the arrival of fire responders.

[0242] The FIGRA value of untreated EPS was 16.4 kW/m²s. [0243] The phenolic-EPS FIGRA was 19.3 kW/m²s. This may be explained as phenolic-EPS contains fire-retardant ingredients and reaches its relatively low pHRR of 193 kW/m² very quickly (10 s) during combustion, whereas the untreated EPS melted and accumulated during combustion, and took 45 s to reach its pHRR of 740 kW/m².

[0244] The three foams according to present disclosure had FIGRA values ranging from 9.3 kW/m²s to 16.3 kW/m²s. This indicated that these foams possessed improved resistance to burning and flash over.

Average heat release rate (mHRR)

[0245] The introduction of fire-retardant additives dramatically decreased the average heat release rate (mHRR) from 315.2 kW/m² for untreated-EPS, to 65.0 kW/m² for phenolic-EPS, and to 65.4 kW/m², 60.2 kW/m² and 58.8 kW/m² for formulations F145, F151 and F153 respectively.

Carbon Monoxide (CO) Release

[0246] The overall CO yield of the foams according to the present disclosure (<0.1451 kg/kg) were lower than that of phenolic-EPS (0.1902 kg/kg). The release of toxic gases such as CO in a fire can seriously reduce the chances of survival.

Thermogravimetric analysis

[0247] The various foams were subjected to thermogravimetric analysis and the residual weights of each foam are presented in Table 7.

[0248] The untreated EPS had almost completely disintegrated, while the foams according to the present disclosure had about one third of their mass remaining. This was almost twice that of the phenolic EPS foam. The average mass loss rate from the cone tests also reflected low mass loss rate.

[0249] All foams according to the present disclosure performed well and decreased the mass loss rate relative to untreated EPS and phenolic-EPS. The results indicated that the copolymer/fire retardant additives of the presently disclosed composites advantageously restrained the combustion of the foam composites.

Example 5: Polyhydroxy compounds

[0250] Alternative polyhydroxy compounds to lignin were examined based on Formula 145 (F145) of Example 2. Lignin was replaced with starch (potato or corn) or tannic acid. The coating and drying process, mechanical strength, and fire retardant performance of the composite foams are collected in Table 8.

[0251] All of the polyhydroxy compounds performed well and in particular both potato starch and corn starch afforded composite foams which quickly self-extinguished and produced a dense char. Example 6: Surface coated composites

[0252] As a further fire protection measure the presently disclosed fire retardant composites were treated on one or more surfaces with a fire retardant surface coating. The fire retardant surface coating comprised polymeric binders (XA: styrene acrylic copolymer or AcPDMS: acrylic modified polydimethylsiloxane) and various fire retardant (FR) additives. Table 9 summarises the surface coating formulations evaluated. The composition of the surface coatings are based on wt.% of each component after drying of the coating.

[0253] Samples SC1 , 2, and 3 prepared using XA polymeric binder exhibited impressive fire retardant performance. However the coatings tended to develop cracks when subjected to rapid drying methods. Removing the clay reduced the paint cracking without obviously affecting the fire retardant and char performance.

[0254] The AcPDMS displayed good painting characteristics with no cracks and heightened water resistance capabilities. For example the SC5 coating had a smooth texture and was devoid of cracks. Notably, during a torch-burning test, this coating exhibited a substantial and densely packed char formation.

[0255] It was also found that the APP in SC5 could be substituted by MPP to afford similar results. Furthermore, the lignin in SC5 was replaced by corn or potato starch to afford similar results. Example 7: Polymer binder variation in surface coating

[0256] Various polymeric binders were evaluated in the surface coating formulation comprising fire retardant additives ammonium polyphosphate, lignin and expandable graphite. The following polymeric binders were tested.

[0257] XG9018 (crosslinked styrene acrylic copolymer)

[0258] EVA (Vinnapas® EZ3112 ethylene vinyl ester copolymer

[0259] AcPDMS (acrylic modified polydimethylsiloxane)

[0260] Table 10 summarises the results.

[0261] The results indicated that a variety of polymeric binders were useful in formulating the surface coating.

Example 8: Flame retardant performance of surface coatings

[0262] An uncoated fire retardant foam composite according to the present disclosure of thickness 50 mm and having a BFR/EPS ratio of about 4.5 was subjected to a flame test.

[0263] A propylene gas flame was supplied by a Bluejet Maxgas fuel cell (400 gram) equipped with a Blue jet JET408 cyclone flame torch, (Cigweld, Australia). The gas was ignited, turned to maximum gas flow and the flame allowed to stabilise for 5 seconds. The torch head was positioned 5 cm from the surface of the foam composite. Flame pass-through time was recorded as the time from the flame hit the surface of the composite to the time smoke was detected from the back of the composite. The flame pass-through time for the uncoated fire retardant foam composite according to the present disclosure was less than 3 minutes.

[0264] Fire retardant foam composites according to the present disclosure of thickness 50 mm, having a BFR/EPS ratio of about 2 and 3 were coated on a surface with a fire retardant coating having a dry composition of about 20 wt.% polymeric binder, 32 wt.% expandable graphite, 20 wt.% lignin, and about 27 wt.% ammonium polyphosphate. The surface coated foam composites were subjected to a flame test by directing a flame onto the coated surface. The flame pass through times were 4.5 minutes and 6 minutes respectively.

[0265] The results indicated that the amount of fire retardant additives in the foam composite material could be substantially reduced (representing significant cost reduction) and when the foam composite was surface coated with only a 0.3 mm thick fire retardant coating the fire retardant performance of the surface coated foam composite was significantly enhanced and outperformed the uncoated foam composite having higher amounts of flame retardant additives.

Example 9: Summary of various flame pass-through time tests

[0266] Expanded polystyrene, a fire retardant foam composite according to the present disclosure having a BFR/EPS ratio of 3/1, and a surface coated fire retardant foam composite, all of 50 mm thickness, were subjected to an open flame and the flame pass-through times are shown in Table 11.

[0267] It can be seen that the fire retardant foam composite according to the present disclosure had a significantly longer (36 sec) flame pass-through time compared to the EPS (<2 sec). When coated with flame retardant coatings SCO or SC5 (see Table 9; coating thickness 0.3 mm) the flame pass-through times were markedly increased, particularly for the coated foam composite according to the present disclosure where the flame pass-through time increased by more than an order of magnitude (from 36 sec. to between 390 sec. and 480 sec. The results highlight the remarkable effect of combining the foam composite of the present disclosure with the surface coating of the present disclosure in extending flame protection time.

Claims

1. A fire retardant particulate composition comprising coated expandable polystyrene beads, wherein the coating comprises one or more copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomers, and one or more fire retardant additives.

2. The fire retardant particulate composition according to claim 1 , wherein the unsaturated carboxylic acid comprises one or both of methacrylic acid and acrylic acid.

3. The fire retardant particulate composition according to claim 1 or claim 2, wherein the unsaturated carboxylic ester comprises one or both of methacrylic ester and acrylic ester.

4. The fire retardant particulate composition according to any one of claims 1 to

3, wherein the unsaturated carboxylic ester comprises one or more of alkyl methacrylate and alkyl acrylate, wherein the alkyl group comprises a Ci to C10 linear or branched alkyl.

5. The fire retardant particulate composition according to any one of claims 1 to

4, wherein the unsaturated carboxylic ester comprises one or more of methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n- butyl acrylate. 2-ethylhexyl acrylate, and iso-octyl acrylate.

6. The fire retardant particulate composition according to any one of claims 1 to

5, wherein the copolymer is crosslinked.

7. The fire retardant particulate composition according to any one of claims 1 to

6, further comprising units derived from one or more diketo acrylamide monomers, such as diacetone acrylamide (DAAM).

8. The fire retardant particulate composition according to claim 7, wherein the copolymer is crosslinked via pendant ketone carbonyl moieties.

9. The fire retardant particulate composition according to claim 7 or claim 8, wherein the copolymer comprises ketimine crosslinking moieties.

10. The fire retardant particulate composition according to any one of claims 1 to

9, wherein the copolymer has a Tg from about 10°C to about 40°C, or from about 15°C to about 35°C, or from about 20°C to about 35°C.

11. The fire retardant particulate composition according to any one of claims 1 to

10, wherein the copolymer has a minimum film formation temperature of at least 20°C.

12. The fire retardant particulate composition according to any one of claims 1 to

11 , wherein units derived from styrene in the copolymer are from about 60 wt.% to about 95 wt.%, based on the total weight of the copolymer.

13. The fire retardant particulate composition according to any one of claims 1 to

12, wherein a 50 wt.% dispersion of the copolymer in water has a dynamic viscosity from about 1000 to about 3000 mPa.s measured at 25°C.

14. The fire retardant particulate composition according to any one of claims 1 to

13, wherein the expandable polystyrene beads are partially expanded.

15. The fire retardant particulate composition according to any one of claims 1 to

14, wherein the expandable polystyrene beads have a density from about 10 kg/m³ to about 30 kg/m³.

16. The fire retardant particulate composition according to any one of claims 1 to

15, wherein the one or more fire retardant additives comprise one or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

17. The fire retardant particulate composition according to claim 16, wherein the polyphosphate comprises one or more of melamine polyphosphate and ammonium polyphosphate.

18. The fire retardant particulate composition according to claim 16 or claim 17, wherein the inorganic filler comprises one or more of layered aluminosilicate, aluminium trihydrate, magnesium hydroxide, zinc borate, boric acid, limestone, calcium carbonate, sodium bicarbonate, sodium carbonate, alumina, silica, fly ash, iron oxide, and fibre glass.

19. The fire retardant particulate composition according to any one of claims 16 to

18, wherein the thermally expandable material comprises one or more of expandable graphite and expandable vermiculite.

20. The fire retardant particulate composition according to any one of claims 16 to

19, wherein the polyhydroxy compound comprises one or more of lignin, alkaline lignin, starch (such as corn starch or potato starch), glucose, pentaerythritol, sorbitol, dextrin, tannic acid, and di pentaerythritol.

21. The fire retardant particulate composition according to any one of claims 1 to

20, wherein the composition comprises:

(a) from about 10 wt.% to about 50 wt.% expanded polystyrene beads;

(b) from about 10 wt.% to about 30 wt.% of one or more copolymers; and

22. The fire retardant particulate composition according to any one of claims 1 to

21 , wherein the copolymer comprises:

(a) from about 60 wt.% to about 95 wt.% of units derived from styrene;

23. The fire retardant particulate composition according to claim 21 or claim 22, wherein the copolymer further comprises from about 1 to about 5 wt.% of units derived from diketo acrylamide, such as diacetone acrylamide.

24. The fire retardant particulate composition according to any one of claims 16 to 23, wherein the composition comprises two or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

25. The fire retardant particulate composition according to any one of claims 16 to

24, wherein the composition comprises three or more of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

26. The fire retardant particulate composition according to any one of claims 16 to

25, wherein the composition comprises each of polyphosphate, inorganic fillers, thermally expandable materials, and polyhydroxy compounds.

27. The fire retardant particulate composition according to any one of claims 16 to

26, wherein the composition comprises one or both of ammonium polyphosphate and melamine polyphosphate, one or both of layered aluminosilicate and aluminium trihydrate, one or both of lignin, corn starch, potato starch, tannic acid and pentaerythritol, and expandable graphite.

28. The fire retardant particulate composition according to any one of claims 1 to

27, wherein a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expandable polystyrene in the fire retardant particulate composition is from 1:1 to 5:1.

29. A method of producing the fire retardant particulate composition according to any one of claims 1 to 28 comprising the steps of combining an aqueous dispersion of copolymer with one or more fire retardant additives, and combining the resulting dispersion with expandable polystyrene beads.

30. The method according to claim 29, wherein the resulting dispersion is combined with the polystyrene beads in a rotating mixer or fluidised bed.

31. The method according to claim 29 or 30, wherein the aqueous dispersion of copolymer and one or more fire retardant additives comprises from about 10 wt.% to about 50 wt.% water.

32. The method according to any one of claims 29 to 31 , wherein the aqueous dispersion of copolymer and one or more fire retardant additives further comprises one or more rheological additives, dispersants, and defoamers, such as xanthan gum.

33. A fire retardant foam composite formed from the fire retardant particulate composition according to any one of claims 1 to 28.

34. The fire retardant foam composite according to claim 33, wherein the density of the foam composite is greater than 20 kg/m³, or greater than 25 kg/m³, or greater than 30 kg/m³, or greater than 35 kg/m³, or greater than 40 kg/m³, or greater than 45 kg/m³, or greater than 50 kg/m³, or greater than 55 kg/m³.

35. A surface coated fire retardant foam composite comprising the fire retardant foam composite according to claim 33 or claim 34, coated on one or more surfaces with a fire retardant surface coating, said fire retardant surface coating comprising one or more polymeric binders and one or more fire retardant additives.

36. The surface coated fire retardant foam composite according to claim 35, wherein the one or more polymeric binders in the fire retardant surface coating comprises one or more of copolymers derived from styrene monomer and one or more unsaturated carboxylic acid and/or unsaturated carboxylic ester monomer, including crosslinked copolymers thereof; copolymers of ethylene and vinyl esters; and acrylic modified polydialkylsiloxanes, such as polydimethylsiloxanes.

37. The surface coated fire retardant foam composite according to claim 35 or claim 36, wherein the one or more fire retardant additives in the fire retardant surface coating comprise one or more of polyphosphate, thermally expandable materials, and polyhydroxy compounds.

38. The surface coated fire retardant foam composite according to claim 37, wherein the fire retardant surface coating further comprises one or more inorganic fillers.

39. The surface coated fire retardant foam composite according to any one of claims 35 to 38, wherein the fire retardant surface coating comprises:

(a) from about 10 wt.% to about 40 wt.% of one or more polymeric binders;

(b) from about 5 wt.% to about 30 wt.% of one or both of ammonium polyphosphate and melamine polyphosphate;

(c) from about 15 wt.% to about 50 wt.% of thermally expandable materials; and

(d) from about 5 wt.% to about 30 wt.% of one or more polyhydroxy compounds. based on the total weight of the fire retardant surface coating.

40. The surface coated fire retardant foam composite according to claim 39, wherein the fire retardant surface coating comprises:

(a) from about 15 wt.% to about 35 wt.% of one or more polymeric binders;

(c) from about 20 wt.% to about 45 wt.% of thermally expandable materials; and

41. The surface coated fire retardant foam composite according to claim 39 or claim 40, wherein the fire retardant surface coating further comprises from about 2 wt.% to about 15 wt.% of one or more inorganic fillers.

42. The surface coated fire retardant foam composite according to any one of claims 35 to 41 , wherein a ratio of the sum of the weights of copolymer and one or more fire retardant additives to a weight of expanded polystyrene in the fire retardant foam composite, not including the fire retardant surface coating components, is from 1 : 1 to 5: 1 , or from 1 : 1 to 4: 1 , or from 1:1 to 3: 1 , or from 1.5:1 to 5: 1 , or from 1.5:1 to 4: 1 , or from 1.5:1 to 3: 1 , preferably less than 3:1, or from 1:1 to 3: 1.

43. The surface coated fire retardant foam composite according to any one of claims 35 to 42, wherein the thickness of the fire retardant surface coating is from about 0.1 mm to about 2 mm, preferably from about 0.1 mm to about 1 mm.

44. A fire retardant surface coating according to any one of claims 35 to 43.

45. The fire retardant foam composite according to claim 33 or claim 34, or the surface coated fire retardant foam composite according to any one of claims 35 to 43, wherein the limiting oxygen index of the fire retardant foam composite or surface coated fire retardant foam composite is greater than 20%, as determined according to ASTM D2863-97.

46. The fire retardant foam composite according to claim 33 or claim 34, or the surface coated fire retardant foam composite according to any one of claims 35 to 43, wherein the peak heat release rate is less than 200 kW/m² at an incident heat flux of 50 kW/m², as determined according to ASTM E1354.

47. A method of producing the fire retardant foam composite according to claim 33 or claim 34, comprising the step of molding the fire retardant particulate composition according to any one of claims 1 to 28 in the presence of steam.

48. A method of producing the surface coated fire retardant foam composite according to any one of claims 35 to 43, comprising the step of coating a surface of the fire retardant foam composite of claim 33 or claim 34 with a fire retardant surface coating.

49. A method according to claim 48, wherein the fire retardant surface coating is applied as an aqueous dispersion to a surface of the fire retardant foam composite by brushing or spraying.

50. A method according to claim 49, wherein the aqueous dispersion of the fire retardant surface coating comprises from about 10 wt.% to about 50 wt.% water.

51. A method according to claim 49 or claim 50, wherein the aqueous dispersion of fire retardant surface coating comprises one or more rheological additives, dispersants, and defoaming agents.

52. A composite block, panel or sheet comprising the fire retardant foam composite according to any one of claims 33, 34, 45, or 46 or the surface coated fire retardant foam composite according to any one of claims 35 to 43, 45, or 46.

53. Use of the composite block, panel or sheet according to claim 52 in building or construction.