Polyurethane foam

Abstract

A foam-forming composition for producing a flexible polyurethane foam includes a polyol component comprising one or more polyether polyols having a hydroxyl value of 25 to 100 mg KOH / g, as determined according to ASTM D4274, and having 2 to 8 hydroxyl groups per molecule; an additive component comprising ammonium polyphosphate and an alkaline earth metal in a weight ratio of 1.3:1 to 6.5:1 and present in an amount of 6 to 50 parts by weight based on 100 parts by weight of the polyol component; and an isocyanate component comprising one or more aromatic isocyanates. This composition excludes melamine and halogen-containing flame retardants.

Description

Technical Field

[0001] Embodiments relate to foam-forming compositions and flexible polyurethane foams made from such foam-forming compositions.

[0002] Introduction Polyurethane foams, such as flexible polyurethane foams, are used in comfort applications such as mattresses, cushions, pads, stuffing, or upholstered furniture (e.g., to provide support and load-bearing). Such polyurethane foams typically contain flame retardant additives. However, users of flexible polyurethane foams, such as consumers and manufacturers of bedding and furniture, are increasingly demanding that such foams be free of certain flame retardant (FR) additives, particularly melamine and halogenated compounds (e.g., fluorinated flame retardants, chlorinated flame retardants, and brominated flame retardants - including those known in the art). Increasingly, regulations are phasing out the use of melamine and halogen-containing flame retardant additives.

[0003] Such flame retardant additives are widely used in flexible polyurethane foams because they help the foam meet common flammability standards, such as British Standard BS 5852:2006 (commonly referred to as Crib 5), which requires the foam to self-extinguish in a specific maximum weight loss test while exhibiting desirable mechanical and physical properties of the foam, such as high elasticity and low 90% compression set. Alternative flame retardant additives have been proposed. For example, U.S. Patent Application Publication No. 2008 / 0157037 discloses a halogen-free polyurethane foam containing an intumescent flame retardant additive comprising ammonium polyphosphate (35 - 45 wt%), melamine (35 - 45 wt%) and pentaerythritol (15 - 25 wt%) as part of a dryer seal assembly. However, such compositions still require melamine, and thus there is a need for alternative compositions that are free of both halogen and melamine while still exhibiting good physical and mechanical properties.

Summary of the Invention

[0004] An embodiment can be realized by providing a foam-forming composition for producing a flexible polyurethane foam, which comprises a polyol component containing one or more polyether polyols, having a hydroxyl value of 25 to 100 mg KOH / g as determined according to ASTM D4274 and having 2 to 8 hydroxyl groups per molecule, an additive component containing ammonium polyphosphate and alkaline earth metal carbonate in a weight ratio of 1.3:1 to 6.5:1 and present in an amount of 6 to 50 parts by weight based on 100 parts by weight of the polyol component, and an isocyanate component containing one or more aromatic isocyanates. The composition excludes (e.g., does not contain, avoids the use of, etc.) melamine and halogen-containing flame retardants.

Modes for Carrying Out the Invention

[0005] According to an embodiment, the flexible polyurethane foam can exhibit improved performance with respect to fire resistance without using melamine and / or halogen-containing flame retardant (FR) additives (for example, those not containing fluorine, chlorine, and bromine-based flame retardants). For example, it is required to avoid the use of tricloropropyl phosphate TCPP. An additive component in a foam-forming composition containing ammonium polyphosphate (APP) and alkaline earth metal carbonate (MC) in a ratio of 1.3:1 to 6.5:1 (for example, 1.4:1 to 6:1, and / or 1.5 to 4.5:1, and / or 3.5:1 to 4.5:1, and / or 3.8:1 to 4.2:1, etc.) (for example, consisting essentially of these) has been found to provide a flexible polyurethane foam having improved flame retardancy. Such an additive component can exclude (for example, can be free of) melamine flame retardants and / or halogen-containing flame retardants. The amount of the additive component in the foam-forming composition is based on the total weight of the polyol component in the foam-forming composition. For example, the additive component can be present in an amount of 6 parts to 50 parts (for example, 8 to 40 parts) based on 100 parts (total weight) of the polyol component, excluding the weight of any of the isocyanate component, additive component, water, catalyst, and surfactant. In an exemplary embodiment, the additive component consists essentially of ammonium polyphosphate and at least one selected from the group of calcium carbonate, magnesium carbonate, and barium carbonate.

[0006] The foam-forming composition can further contain water (for example, as a chemical blowing agent), and optionally can contain one or more other physical or chemical blowing agents. The foam-forming composition can further contain one or more catalysts such as amines and / or tin catalysts (for example, tertiary amine catalysts). Also, the foam-forming composition can contain a surfactant such as a silicone surfactant. In addition, the foam-forming composition can contain one or more cell openers, and / or one or more chain extenders, and / or one or more crosslinking agents to assist in the preparation of a lightweight and flexible open-cell foam.

[0007] The polyurethane foam according to the embodiment can pass the BS 5852 Crib 5 flammability test and / or the UNI 9175 flammability test, and achieve a Class 1M evaluation. Further, by including a polyisocyanate polyaddition (PIPA) polyol in the foam-forming composition, the fire resistance can be further improved. Further, the foam-forming composition can find a wide range of applications and enable improved fire resistance in flexible polyurethane foams having any elasticity from 25% to 85% as determined according to ASTM-D3574-16 (2016). As used herein, the term "ASTM" refers to publications of ASTM International, Conshohocken, Pa. As used herein, the term "UNI" refers to publications of the Italian Organization for Standardization, Milan IT.

[0008] Flexible polyurethane foams include both conventional flexible foams and high-resilience foams. As used herein, the term "conventional flexible" polyurethane foam may contain or be derived from a polyether polyol having a secondary hydroxyl group, or mainly secondary hydroxyl groups, such as found in polyols derived from propylene oxide (PO), and may refer to such foams that may contain one or more isocyanates in the isocyanate component. As used herein, the term "high-resilience" (HR) flexible polyurethane foam may contain or be derived from a polyether polyol having a primary hydroxyl group, such as an ethylene oxide (EO) group, and may refer to such foams that may contain one or more prepolymers made from methylene di(phenyl isocyanate) or MDI in the (f) polyisocyanate component. The wide formulation flexibility of the foam and the foam-forming composition further allows for the inclusion of additional polyols such as polyester polyols and / or PIPA polyols.

[0009] Polyurethane foams have a compressive strength of 100 kg / m, determined according to ISO 845 3 It may have a density of 10 kg / m 3 ~90kg / m 3 , 20kg / m 3 ~70kg / m 3 , 25kg / m 3 ~60kg / m 3 The flexible polyurethane foam may have a resilience of 25-85%, or at least 30%, or at least 40%, or at least 50%, as determined according to ASTM-D3574-16(2016). The flexible polyurethane foam may exhibit one or more, or all of the following: (i) a passing rating in the Crib 5 British Standard BS 5852:2006 (Crib 5) test, (ii) a Class 1 IM rating according to the UNI 9175 flammability test, (iii) a Crib 5 test, fire time test rating of less than 600 seconds, e.g., less than 450 seconds, or (iv) a Crib 5 weight loss test rating of less than 60g. As used herein, the term "Crib 5" refers to the Upholstery Fill Test, Ignition Source 5, British Standard BS 5852:2006, "Methods of test for assessment of the ignitability of upholstered seating by smouldering and flaming ignition sources", British Standard (BSI), London, UK, 2006.

[0010] Flexible polyurethane foams may have a resilience of 25-85%, or, for example, 55% or more for high resilience foams, as determined according to ASTM-D3574-16(2016).Unless otherwise indicated, temperature and pressure conditions are ambient (21-24°C), relative humidity 50%, and standard pressure (1 atm).

[0011] The polyol component of the foam-forming composition has a hydroxyl value of 25 to 100 mg KOH / g as determined according to ASTM D4274, has 2 to 8 hydroxyl groups per molecule (in other words, has 2 to 8 average hydroxyl functionality), and may include one or more polyether polyols.

[0012] The polyether polyol may contain a reaction product or adduct of at least one initiator having 2 to 8 hydroxyl functional groups, such as water, or propylene glycol, or ethylene glycol, or glycerol, or trimethylolpropane, or sorbitol, or sucrose, and one or more alkylene oxides, such as ethylene oxide, propylene oxide, or a combination thereof. The one or more polyether polyols may be (i) a mixed feed polyether polyol having an ethylene oxide (EO) content of 0.3 to 40% by weight based on the total weight of all EO and PO in the polyether polyol, (ii) a polyether polyol having a propylene oxide (PO) content of 100% by weight based on the total weight of all EO and PO in the polyether polyol, (iii) a propylene oxide (PO) polyether polyol end-capped with 10 to 25% by weight of ethylene oxide (EO) based on the total weight of all EO and PO in the polyether polyol, or (iv) a polyisocyanate polyaddition (PIPA) polyether polyol dispersion of polyurethane particles in a polyether polyol carrier, wherein each polyurethane particle contains at least two carbamate bonds, and may be selected from a polyisocyanate polyaddition (PIPA) polyether polyol dispersion.

[0013] As used herein, the term "hydroxyl value," expressed as mg KOH / g of analyte, refers to the amount of KOH required to neutralize acetic acid incorporated in the acetylation of 1 gram of the analyte material, as determined in accordance with ASTM D4274. The term "average hydroxyl value" refers to the weight average of the hydroxyl values of a mixture of hydroxyl-functional compounds. For example, a 50 / 50 mol% mixture of (i) a PIPA polyol having a hydroxyl value of 80 and (ii) a total propylene oxide (PO) polyether polyol having a hydroxyl value of 60 will have an average hydroxyl value of 0.5(80) + 0.5(60), or (40 + 30), or 70. As used herein, the term "hydroxyl equivalent," or "equivalent weight," or "EW" of a given polyether polyol, or polyol, refers to the calculated value determined by the following formula: EW = 56,100 / hydroxyl value of the given polyol. As used herein, the term "hydroxyl functionality" refers to the number of hydroxyl groups in the ideal formula of a given diol, or polyol, and not to each of the impurities, or variations, in the formula. The actual hydroxyl functionality of a given polyol can be lower than the nominal hydroxyl functionality for various reasons known in the art.

[0014] As used herein, the term "molecular weight," or "MW" of a given polyether polyol, or polyol, refers to the calculated value determined by the following formula: MW = (56,100 / hydroxyl value) X nominal hydroxyl functionality of the polyol.

[0015] Unless otherwise specified, as used herein, the term "isocyanate index", or simply "index", is expressed as the number obtained by multiplying by 100 the ratio of the number of equivalents of isocyanate functional groups to the number of equivalents of active hydrogen, such as hydroxyl groups, in a given polyurethane (foam)-forming reaction mixture. For example, in a reaction mixture where the number of equivalents of isocyanate is equal to the number of equivalents of active hydrogen, the isocyanate index is 100. As used herein, the term "isocyanate-reactive group" refers to active hydrogen, such as the hydrogen in a hydroxyl group.

[0016] As used herein, the term "isocyanate" refers to an isocyanate group containing a material having one or more isocyanate functional groups, such as an isocyanate-terminated prepolymer, polyisocyanate or biuret, allophanate, isocyanurate, carbodiimide, its dimer, trimer, or oligomer, etc., prepared by the reaction of an isocyanate with one or more other compounds.

[0017] As used herein, the term "particle size", or "particle size diameter (PSD)", means the particle size diameter of a given material determined by laser light scattering and is reported as the volume % of particles in a dispersion having a specific maximum particle size. As used herein, the phrase "weight %" represents weight percent.

[0018] The flexible polyurethane foam can be made from a foam-forming composition of a two-component reaction mixture of an isocyanate component and an isocyanate-reactive component, which includes (a) a polyol component containing one or more polyols such as polyethers and / or PIPA polyols, (b) an additive component containing a combination of ammonium polyphosphate (APP) and alkaline earth metal carbonate (MC) in a weight ratio of APP:MC of 1.3:1 to 6.5:1, and (c) potentially other components such as water, one or more catalysts, and one or more surfactants. The foam-forming composition and the flexible polyurethane foam made therefrom do not contain melamine and halogen-containing flame retardants. The alkaline earth metal carbonate (MC) may include at least one selected from the group consisting of calcium carbonate, magnesium carbonate, and barium carbonate.

[0019] The foam-forming composition can enjoy a wide formulation window and includes compositions that form low-density, high-elastic polyurethane foams and conventional elastic slabstock polyurethane foams, which are characterized by improved flame retardant performance. The flexible polyurethane foam can have improved flame retardant performance. The properties of the foam-forming composition can determine low- or high-elastic foam formation. For example, high-elastic foams can occur from a foam-forming composition having more or exclusively primary hydroxyl groups such as in the form of condensed ethylene oxide (EO) groups, and / or in a composition having, for example, methylene di(phenyl isocyanate) (MDI) in a condensed form. On the other hand, conventional elastic foams can contain all secondary hydroxyl groups such as in the form of condensed propylene oxide (PO) groups, or, for example, a PO / EO mixed feed polyether polyol.

[0020] The polyol component contains one or more polyether polyols having a hydroxyl value of 25 to 100 mg KOH / g (for example, 28 to 80 mg KOH / g) as determined according to ASTM D4274 and having 2 to 8 (for example, 2 to 6) hydroxyl groups per molecule. The one or more polyether polyols may have a weight average molecular weight of 1100 g / mol to 18000 g / mol (for example, 2400 to 15000, 3000 to 10000, etc.). The polyether polyol composition may have an equivalent per hydroxyl group of more than 550 (for example, at least 700, at least 1000, at least 1200, or at least 1500, and may be up to 2250, up to 2000, or up to 1800, etc.).

[0021] Such polyether polyols can be formed from initiators having at least two hydroxyl groups. The nominal hydroxyl functionality, or the number of hydroxyl groups, of each polyether polyol is equal to the number of hydroxyl groups in the initiator. Suitable initiators may have 2 to 8 hydroxyl groups (for example, 2 to 6 hydroxyl groups). Suitable polyether polyols useful as (a) one or more polyol components for making flexible polyurethane foams can be formed from co-starting diols and triol initiators. Examples of initiators include, for example, glycerol, erythritol, pentaerythritol, diglycerol, sorbitol, sucrose, sugar alcohols, and other polyhydric alcohols. Examples of diols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, thiodiethanol, N-methyldiethanolamine, and dipropylene glycol. Examples of triol initiators may include glycerol, trimethylolpropane, and triethanolamine. Bifunctional aliphatic polyether polyols can be formed from only diol initiators, and when triol initiators are used, trifunctional polyether polyols can result.

[0022] The polyol component may include at least one polyether polyol having a hydroxyl value of 30 to 40 mg KOH / g.

[0023] (a) The polyether polyol in the polyol component of the foam-forming composition may be selected from any of the following: (i) A mixed-feed polyether polyol (mixed-feed polyether polyol (i)) having an ethylene oxide (EO) content of 1 to 40% by weight (e.g., 5 to 30% by weight, 10 to 30% by weight) and a propylene oxide (PO) content of 60 to 99% by weight (e.g., 70 to 95% by weight, 70 to 90% by weight) based on the total weight of all EO and PO in the polyether polyol. (ii) A polyether polyol (PO polyether polyol (ii)) having a propylene oxide (PO) content of 100% by weight based on the total weight of all EO and PO in the polyether polyol. (iii) A propylene oxide (PO) polyether polyol end-capped with 10 to 30% by weight of ethylene oxide (EO) (EO end-capped PO polyether polyol (iii)) based on the total weight of all EO and PO in the polyether polyol. (iv) A polyisocyanate polyaddition (PIPA) polyol dispersion of polyurethane and / or polyurethane-urea particles in a polyol carrier (PIPA polyol). For example, the PIPA polyol may be a dispersion of polyurethane and / or polyurethane-urea particles in a carrier polyol, and the carrier polyol has an average molecular weight of 200 to 12000 g / mol (e.g., 400 to 6000 g / mol) and an average of at least two hydroxyl groups per molecule.

[0024] The polyol component may include a mixture of two or more polyols, such as, for example, a mixture of a mixed feed polyether polyol (i) and a (PO) polyether polyol (ii), a mixture of a mixed feed polyether polyol (i) and an EO end-capped PO polyether polyol (iii), or a mixture of a PO polyether polyol (ii) and an EO end-capped PO polyether polyol (iii). Optionally, a PIPA polyol. For example, (a) one or more polyether polyols in a condensed form include a mixture of a (v)(iv) PIPA polyol and any one or more of the polyether polyols (i), (ii), or (iii), and this mixture in a condensed form includes 10 to 99% by weight (for example, 20% by weight or more) of the (iv) PIPA polyol. The polyol component may include a PIPA polyol or a mixture of a (iv) PIPA polyol and a polyether polyol, and this mixture has an average hydroxyl value of 25 to 100 (for example, 28 to 75) determined in accordance with ASTM D4274.

[0025] A suitable (a)(iv) (PIPA) polyol for the foam-forming composition can include a dispersion of polycarbamate particles dispersed in a polyether polyol carrier. Suitable PIPA polyols can be made by known polymerization in the presence of one or more polyisocyanates such as (d4) diisocyanate, with an excess of (d1) polyether polyol, (d2) compatible seed polyol, and (D3) co-reactant polyol, as disclosed in Cookson et al.'s U.S. Patent Application Publication No. 2014 / 0051778A1. The PIPA polyol dispersion can be created by introducing the PIPA polyol under shear force to form a reaction mixture and reacting it until the exotherm of the homogeneous dispersion ceases. Thus, the (a)(v) PIPA polyol can be the product of a reaction mixture in the presence of an excess of (d1) polyether polyol carrier (e.g., one or more propoxylated or oxyethylene end-capped polyether polyols having a molecular weight MW of 200 to 6000 g / mol and an average hydroxyl functionality of 2 or 3), (d2) compatible seed polyol, and (d3) one or more co-reactant polyols (e.g., triethanolamine (TEOA) or diethanolamine (DEOA)), with (d4) one or more polyisocyanates (e.g., aromatic polyisocyanates).

[0026] (a)(iv) Suitable polyether polyols as carrier (d1) in PIPA polyol can be any known polyether polyol known in the art having 2 to 8 hydroxyl groups and an MW of up to 6000 g / mol. For example, polyether polyols obtained by addition polymerization of at least one oxyalkylene compound having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide, to a lower aliphatic polyhydric alcohol having an average of 2 to 8 hydroxyl groups can be mentioned. Examples of suitable (d1) polyether polyols can include, for example, oxyethylene end-capped polyols, such as glycerol-initiated ethylene oxide end-capped poly(propylene oxide) copolymer triols having 10 to 19 wt% ethylene oxide in the alkylene oxide feed and a hydroxyl value of 45 to 80 mg KOH / g.

[0027] A suitable amount of all (d1) polyether polyols in PIPA polyol can range from 60 to 99 wt% (e.g., 75 to 88.5 wt%) based on the total weight of the reactants used to make the PIPA polyol (dispersion), and the total wt% totals 100%. Most of the polyether polyol in PIPA polyol can act as a carrier phase in the dispersion.

[0028] (a)(iv) A suitable (d2) compatible seed polyol for use in the preparation of PIPA polyol is obtained by reacting at least one (d4) aromatic isocyanate with a polyol mixture in the presence of an excess of polyol, such as a polyether polyol, with (i) a propylene oxide polyol containing 1 to 30 wt% ethylene oxide based on the total weight of alkylene oxide, or an oxyethylene end-capped propylene oxide polyol, or a triol-initiated polyol of alkylene oxide, and (ii) nitrogen, or a phosphorus atom, and one or more co-reactant polyols having a molecular weight (MW) of up to 400 (e.g., up to 300). The polyol mixture may contain at least 70 wt% of (i) propylene oxide polyol, ethoxylated or oxyethylene end-capped propylene oxide polyol, or a triol-initiated polyol of alkylene oxide. To provide a seed useful for making a high resilience foam, the polyol mixture may contain a polyol having at least 45 wt% (e.g., at least 75 wt%, at least 80 wt%, etc.) of hydroxyl groups as primary hydroxyl groups in the polyol mixture. To provide a seed useful for making a conventional elastic foam, the polyol mixture may contain a polyol having at least 70 wt% (e.g., at least 85 wt%) of hydroxyl groups as secondary hydroxyl groups in the polyol mixture. The isocyanate index can be maintained below 100 to maintain the PIPA-forming co-reactants present in the seed polyol. At least one polyisocyanate used during the reaction to form the (d2) seed polyol can be used to provide a composition having an isocyanate index of 50 to less than 100.

[0029] (d2) A suitable amount of one or more compatible seeds can range from less than 5 wt% (e.g., 2 - 4 wt%) based on the total weight of the reactants used to prepare the PIPA polyol, and the total wt% of the reactants for preparing the PIPA polyol totals 100%.

[0030] In the case of PIPA polyol, one or more co-reactant polyols (d3) can be diols, triols, or oligoether diols having a formula weight of 400 or less, such as triethanolamine (TEOA) or diethanolamine (DEOA). Suitable co-reactive polyols (d3) can include diols such as dihydric alcohols having a molecular weight of 62 to 400. Examples include alkane polyols such as glycols, for example, ethylene glycol, propylene glycol, hexamethylene diol, low molecular weight alcohols containing ether groups, for example, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, or butylene glycol, highly functional alcohols such as polyglycerol, and alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, 2-(2-aminoethoxy)ethanol, diisopropanolamine, TEOA, DEOA, and mixtures thereof.

[0031] (d3) A suitable amount of one or more co-reactive polyols can be in the range of 0.2 to 6 wt% (e.g., 0.5 to 5 wt%) based on the total weight of the reactants used to make the (a)(iv) PIPA polyol, and the total weight % used to make the PIPA polyol totals 100%.

[0032] For the foam-forming composition, the (a)(iv) PIPA polyol can have a solid particle content of 1 to 40 wt%, or 11.5 to 25 wt%, or 5 to 15 wt% based on the total weight of the PIPA polyol. The particles can be uniformly distributed as a dispersion in the polyol carrier, and the particle size distribution (PSD) of 90 volume % of the particles in the dispersion, determined by laser light scattering, can have a maximum PSD of 0.1 to 10.0 μm (e.g., 0.2 to 5.0 μm, 0.2 to 2.5 μm).

[0033] The polyol carrier in each PIPA polyol can depend on the foam application for which it is used. The low molecular weight polyol (ii) can be found to be suitable as a carrier in PIPA polyols for use in making conventional foams and viscoelastic foams.

[0034] The polyol component of the foam-forming composition can further include additional polyols, for example, for slabstock foam, a glycerol-initiated ethylene oxide and propylene oxide mixed feed polyol having an MW of 5000, an EO content of 74 wt%, and an OHn of 33. When used, a suitable amount of (g) one or more cell openers can range from 0.05 to 1 wt% (e.g., 0.1 to 0.6 wt%) based on the total weight of the polyol component, and all total weight %s add up to 100.

[0035] The polyol component of the foam-forming composition can further include (h) one or more diol extenders. Examples of diol extenders can include any diol, such as ethylene glycol or butanediol. Such (h) diol extenders can be included in the foam-forming composition as reactants that lower the viscosity of the polyol component and ultimately increase the molecular weight of the polyurethane reaction product made from the diol extender. A suitable amount of (h) one or more diol extenders, when used, can range from 1 to 8 wt% (e.g., 1.5 to 6 wt%) based on the total weight of the polyol component, and all total weight %s add up to 100%.

[0036] The polyol component of the foam-forming composition may further include (j) one or more polyester polyols if it is desirable to improve the mechanical properties of the flexible polyurethane foam made therefrom or its compatibility with another material or substrate.

[0037] The polyol component of the foam-forming composition may further comprise (l) one or more crosslinking agents. The crosslinking agent may include any triol or other low MW molecule having a hydroxyl functionality higher than 3, such as glycerin, or a glycerin derivative obtained by alkoxylating glycerin with PO to a hydroxyl value of about 620. Such (l) crosslinking agents may be included in the foam-forming composition as reactants that reduce the viscosity of the polyol component and ultimately increase the molecular weight of the polyurethane reaction product made from the crosslinking agent. The preferred amount of (l) one or more crosslinking agents, when used, may range from 1 to 8 wt% (e.g., 1.5 to 6 wt%) based on the total weight of the polyol component, and all total weight percentages add up to 100%.

[0038] The isocyanate component of the foam-forming composition includes one or more isocyanates, such as aromatic isocyanates. Suitable isocyanates for use in the foam-forming composition may be those known in the art and may include, for example, aromatic polyisocyanates, prepolymers, or mixtures of two or more thereof. Examples of useful isocyanates include methylene diphenyl-based isocyanates (e.g., MDI and isocyanate-terminated prepolymers made using MDI), and toluene-based isocyanates (e.g., TDI and isocyanate-terminated prepolymers made using TDI).

[0039] In the foam-forming composition and its method of preparation, the preferred amount of the isocyanate component may be in the range of the amount necessary to provide a foam-forming composition having an isocyanate index of 50 to 150 (e.g., 55 to 125, etc.).

[0040] The foam-forming composition provides a flexible polyurethane foam that exhibits at least one, or both, of (i) a passing evaluation in the bulk frame Crib 5 British Standard BS 5852:2006 (Crib 5) test, or (ii) a Class 1 IM evaluation according to the UNI 9175 flammability test. (b) The combination of additives does not include halogen-containing flame retardants and does not include melamine.

[0041] Furthermore, the polyol component of the foam-forming composition may contain (c) water, or at least one blowing agent, or both. Water and the blowing agent are generally combined with the polyol component separately from the polyisocyanate component. Exemplary blowing agents include water and chemical blowing agents such as formic acid, as well as physical blowing agents such as methylene chloride, carbon dioxide, hydrocarbons, hydrofluorocarbons, methylal, and methyl formate. For example, water can be used in an amount of 1.0 to 7.0% by weight (e.g., 2.5 to 5.0% by weight) based on the total weight of the polyol component.

[0042] To better drive the formation of flexible polyurethane foam, polyurethane formation, or both, the isocyanate-reactive component of the foam-forming composition may further contain (e) one or more catalysts such as, for example, a blowing catalyst, a gelling catalyst such as a metal catalyst, and / or a reactive catalyst such as an amine catalyst or a tertiary amine. The catalyst can be a divalent metal salt catalyst such as a zinc salt or a zinc fatty acid catalyst, a tin salt or a bismuth salt, and / or a tertiary amine such as triethylenediamine or bis-dimethylaminoethyl ether. The preferred total amount of (e) one or more catalysts can range from 0.01% to 5% by weight (e.g., 0.5 to 1.0% by weight, 0.01 to 0.2% by weight, etc.) based on the total weight of the isocyanate-reactive component.

[0043] The isocyanate-reactive component may contain at least one foam stabilizer that helps to stabilize the bubbles formed during the foaming process, such as a silicone surfactant, fillers such as talc, pigments; colorants; reinforcing agents such as fibers or microfibers, biocides, preservatives, antioxidants, and / or other additives known in the art such as self-catalyzed polyols.

[0044] A method of making a flexible polyurethane foam having improved flame retardant properties may include any method of forming the foam using a foam-forming composition. The method may include, for example, forming an isocyanate-reactive component that includes one or more or a mixture of polyether polyols, an ammonium polyphosphate flame retardant, and a combination of additives of calcium carbonate, and combining the polyol component with an isocyanate component. Combining may further include combining the isocyanate-reactive component with the isocyanate component to form a reactive mixture. The reactive mixture may then be injected into a mold such as an open mold or a closed mold. Molding using closed molding or pressure molding facilitates the formation of a highly elastic foam and / or may be a free rise. Alternative methods may include the reaction of various components such as isocyanates, polyols, catalysts, and additives, which are processed according to a continuous slabstock foam manufacturing process typically used in the manufacture on a conventional flexible foam.

[0045] Flexible polyurethane foams may find use in bedding and furniture, or pads such as pillows, mattresses, and cushions for chairs and sofas, and in their layers such as mattress toppers in European style mattresses.

Examples

[0046] The following examples illustrate exemplary embodiments. Unless otherwise specified, all temperatures are ambient temperature (21 - 24 °C), all pressures are 1 atmosphere, and the relative humidity (RH) is 35%. The numerical ranges and parameters indicating the broad scope of the present invention are approximate values, but the numerical values shown in the specific examples are reported as accurately as possible. Any numerical values inherently include certain errors that necessarily result from the standard deviation found in each test measurement.

[0047] The materials used in the following examples and not otherwise defined are listed in Table 1 below. The abbreviations used in the examples include the following: APP: ammonium polyphosphate; CC: calcium carbonate; CLD: compressive load distortion; DEOA: diethanolamine; EO: ethylene oxide; FR: flame retardant additive; HR: high elasticity; OHn: hydroxyl value; PIPA: polyisocyanate polyaddition; PO: propylene oxide; SO: stannous octoate.

[0048]

Table 1

[0049] In Table 1 above, Isocyanate 1 is a prepolymer formed by the reaction of an isocyanate component and a polyol component. The isocyanate component was added to a reactor and brought to the reaction temperature (about 70 °C) while stirring under a nitrogen atmosphere. The polyol components (Polyol G and Polyol H) were premixed and then gradually added to the reactor at a rate low enough to allow removal of the heat generated by the reaction of the isocyanate groups and the hydroxyl groups. After the addition of the polyol components was complete, the prepolymer was consumed by maintaining it at about 70 °C while monitoring the NCO content according to the method described in ASTM D5155. The prepolymer formation was considered complete when the NCO content reached the target NCO value of 30 wt% based on the total amount of the prepolymer.

[0050] Conventional Elastic Open Box Foam Formation: To form the foams shown in Tables 5 and 6 below, free-rise foams were formed in a laboratory-scale open cardboard box by manually mixing and casting in a simplified method that mimics the slabstock flexible foam manufacturing process. All stages of the foam formation process were carried out in a draft chamber or under a hood. All chemicals used in the formulation were equilibrated at room temperature before use. A 27-liter cardboard box (30×30×30 cm) with an open top was used to make the foam. For the formation of the polyol component, the polyol was accurately weighed into a 2.2-liter plastic bucket, and the surfactant and water were added to the polyol. Then, while mixing by hand to prevent lumping, all solid materials were slowly added to the polyol. If there were two or more solid additives, these were mixed before introducing them into the polyol component. Then, the amine catalyst was introduced into the polyol component. When used, the gelling catalyst stannous octoate (SO) was moistened, weighed into a tared syringe, and placed horizontally. The required amount of polyisocyanate was weighed into a separate plastic container, rinsed with isocyanate, tared, and the plastic container was weighed after dispensing the polyisocyanate into the open box to compensate for the polyisocyanate remaining in the container after dispensing.

[0051] For the polyol component and then the manual mixing to form the two-component composition, the mixer speed was set to 2000 rpm and the following mixing procedure was used: (i) Start the stopwatch and the rise profiling (foam height measurement) software. (ii) At 5 seconds, start mixing the polyol component with water and surfactant, and add the solid additives and then the amine catalyst. (iv) At 30 seconds, add the gelling catalyst (SO) to the polyol component. (v) At 40 seconds, add the isocyanate (this is taken as t0, or the reaction start time), and (vi) At 50 seconds, stop the mixer and pour the mixture into the box.

[0052] Full rise and blow-off time were recorded. After 5 minutes, when the foam was fully formed, the foam was transferred to an oven set at 140 °C and further cured for 5 minutes. The foam was taken out of the box and left in the draft at ambient temperature overnight to complete the reaction. The resulting foam was crushed using a mechanical roller crusher to release internal bubbles. All physical properties of the conventional elastic foam were tested as shown in Table 2 below.

[0053] Formation of highly elastic molded foam: The foams shown in Tables 3, 4A, and 4B below were produced using a Cannon A 40 high-pressure molding machine (Cannon USA, Cranberry Township, PA) equipped with an FPL mixing head having a 14 mm piston diameter and pre-set to the indicated settings. The mold was heated by water recirculation and treated with a water-free mold release agent. The two-component foam-forming mixture was injected into the mold, and then the mold was closed while the mixture was reacted inside the mold. The resulting foam was then demolded after the time shown below. After demolding, the foam was crushed using a mechanical roller to release internal bubbles. The molding machine and process settings were as follows: Mold size type / size For a 15.1-liter mold, a cavity of 45 cm × 45 cm × 7.5 cm, and for a 10.1-liter mold, 45 cm × 30 cm × 7.5 cm. Polyol temperature 25 - 28 °C. Isocyanate temperature 25 - 28 °C. Foam-forming mixture output 300 g / s. Polyol pressure 157.9 atm (160 bar). Isocyanate pressure 157.9 atm (160 bar). Mold surface temperature 48 °C. Demolding time 5 minutes. Molded product crushing, yes. Mold release agent C 11 -C 12 Isoalkane, <2% aromatic (ACMOS 37 - 4463, or ACMOS 37 - 4477 agent, Acmos Chemie KG, Bremen, DE).

[0054] Test method: In the following examples, the following test methods were used. The standard deviation in all data was within acceptable limits.

[0055] UNI 9175 - Class 1 IM: Small flame test.

[0056] BS 5852 Source 5 (Crib 5): In the Crib 5 test, a white fabric was applied to the cover. Unless otherwise specified, each result is the average of two tests. If self - extinguishing occurs within 10 minutes and the foam weight loss remains < 60 g during the test, the result is "pass" overall. If the Crib 5 test > results in a weight loss of 60 g or fails the self - extinguishing test, the overall result is reported as a fail.

[0057]

Table 2

[0058] In all of the foams shown in the following Tables 3, 4A, 4B, 5, and 6, all materials except isocyanate(s) constituted part of the polyol component.

[0059]

Table 3

[0060] In Table 3, all forms were made within molds having sizes of 45 cm × 45 cm × 7.5 cm (15.1 liters) and 45 cm × 30 cm × 7.5 cm (10.1 liters) to produce form samples as specified in each of the listed tests. As shown in Table 3 above, in the high resilience (HR) forms of Comparative Examples 1 and 2 (CE-1 and CE-2) containing either APP or CC, both forms failed the Class 1 IM test. The CE-3 form, which contains a 1:1 (w / w) additive combination of APP and CC (solids) at 10% solids by weight in the isocyanate-reactive components (e.g., those containing a combination of polyol, water, APP, CC, and other additives excluding only the isocyanate component), also failed the Class 1 IM flammability test. On the other hand, the form of Example 1 of the present invention, which contains a 4:1 (w / w) additive combination blend of APP and CC (solids) at 10% solids by weight in the isocyanate-reactive components, passes the Class 1 IM flammability test.

[0061]

Table 4

[0062]

Table 5

[0063] The forms described in Tables 4A and 4B were made in a mold having sizes of 45 cm × 45 cm × 7.5 cm (15.1 liters) and 45 cm × 30 cm × 7.5 cm (10.1 liters). As shown in Tables 4A and 4B above, Comparative Example CE-1A contains melamine with a solids content of 21% by weight in the isocyanate-reactive component. CE-1A serves as a comparison standard for combustion performance. The form of Example 1A of the present invention, having a solids content of 21% by weight in the isocyanate-reactive component and an APP / CC weight ratio of 4, passed the Crib 5 test. On the other hand, both forms of Comparative Examples CE-2A and CE-3A, each filled with either APP or CC with a solids content of 21% by weight in the isocyanate-reactive component, failed the Crib 5 test. Furthermore, the forms of Examples 2A and 3A of the present invention, having additive combinations with solids content amounts of 25% and 28% by weight, respectively, in the isocyanate-reactive component, passed the Crib 5 test. As the foam weight loss decreased from 29.7% by weight for Example 1A of the present invention to 20% by weight for Example 2A of the present invention, a higher filling amount of the same additive combination of the present invention further improved the fire resistance. Still further, the forms of Examples 4A and 5A of the present invention, having a solids content of 21% by weight in the isocyanate-reactive component, an APP / CC weight ratio of 4, and further containing PIPA polyol, passed the Crib 5 test. In addition, the form of Example 3A of the present invention has improved compression set, demonstrating that a high-performance foam material can have a higher filling amount of additive components.

[0064] The forms created in Table 5 below were made in a free-rise open-top 30 cm × 30 cm box. As shown in Table 5 below, the form of Comparative Example CE-1B includes an open-box form filled with melamine, representing the state of the art. The forms of Comparative Examples CE-2B and CE-3B, each containing a form filled with either CC or APP, failed the Class 1 IM flammability test.

[0065] In contrast to Comparative Examples CE-2B and CE-3B, the foams of Examples 1B, 2B, 3B, and 4B of the present invention, which have the same total additive combination content (19% by weight of the solids of the isocyanate-reactive component) as the form of Comparative Example CE-1B, all passed the UNI 9175 test with a Class 1 IM evaluation at an APP / CC weight ratio in the range of 1.5:1.86 to 2.57:4. On the other hand, the foams of Comparative Examples CE-4B and CE-5B, which contain APP / CC weight ratios of 0.7 and 9, respectively, all failed the UNI 9175 test with a Class 1 IM evaluation. In addition, the foams of Examples 1B, 2B, 3B, and 4B of the present invention exhibit a 90% increased compression set when they contain a relatively larger amount of APP.

[0066]

Table 6

[0067]

Table 7

[0068] The form in Table 6 above was allowed to freely expand in an open-topped 30 cm x 30 cm box. All of Examples 1C, 2C, 3C, 4C, 5C, and 6C of the present invention passed the UNI 9175 flammability test with a Class 1 IM rating. All of the forms contained a certain weight ratio of APP:4 of CC. In Example 1C of the present invention, the form contained Polyol A (100% by weight propylene oxide units based on all alkylene oxides). The forms in Examples 2C, 3C, 4C, and 5C of the present invention, in addition to Polyol A, contained increasing amounts of PIPA polyol (Polyol E), such that an amount of PIPA polyol of 30% by weight or more of all polyols, or more preferably 40% by weight of all polyols, etc., enabled the form to pass more stringent flammability tests such as the Crib 5 test / BS 5852 Source 5. Further, Examples 1C, 2C, 3C, 4C, and 5C of the present invention demonstrate that a flame-retardant flexible polyurethane foam according to an exemplary embodiment can include slabstock foam and other flexible foams having an elasticity of 30 - 55% as determined according to ASTM-D3574-16 (2016). Thus, the scope of the embodiment is not limited to high-elasticity foams.

[0069] Referring to Table 7 below, the examples describe forms having different carbonate properties. Examples 1D, 2D, and 3D of the present invention describe foam formulations each having either calcium (CC), magnesium (MgC), or barium carbonate (BaC) as an alkaline earth metal carbonate source. These foams passed the Crib 5 test. However, Comparative Examples CE-1D, and CE-2D describe forms having either zinc carbonate (ZnC), or sodium carbonate (NaC), which did not pass the Crib 5 test.

[0070] [Table 8] * From Polyol E. ** A mixture of melamine, APP + carbonate (CC, MgC, BaC, ZnC, or NaC).

[0071] Referring to Table 7, alkaline earth metal carbonates, especially magnesium carbonate, calcium carbonate, and barium carbonate, enable similar performance with APP compared to other carbonates.

Claims

1. A foam-forming composition for producing a flexible polyurethane foam, wherein the composition comprises: A polyol component comprising one or more polyether polyols having a hydroxyl value of 25 to 100 mg KOH / g as determined according to ASTM D4274 and having 2 to 8 hydroxyl groups per molecule, The additive component comprises ammonium polyphosphate and alkaline earth metal carbonate in a weight ratio of 1.3:1 to 6.5:1, and is present in an amount of 6 to 50 parts by weight based on 100 parts by weight of the polyol component, A compound comprising an isocyanate component containing one or more aromatic isocyanates, A foam-forming composition that does not contain melamine and a halogen-containing flame retardant.

2. The composition according to claim 1, wherein the additive component essentially consists of ammonium polyphosphate and at least one selected from the group consisting of calcium carbonate, magnesium carbonate, and barium carbonate.

3. The composition according to claim 1, wherein the weight ratio is 1.5:1 to 4.5:

1.

4. The composition according to claim 1, wherein the amount of the additive component is 10 to 30 parts by weight based on 100 parts by weight of the polyol component.

5. The composition according to claim 1, wherein the hydroxyl value of one or more polyether polyols is 30 to 40 mg KOH / g.

6. The composition according to claim 1, wherein the polyol component further comprises PIPA polyol.

7. The composition according to claim 1, wherein the composition further comprises water, one or more catalysts, and one or more surfactants.

8. The composition according to claim 1, wherein the foam-forming composition has an isocyanate index of 50 to 150.

9. The aforementioned flexible polyurethane foam is determined in accordance with ISO 845, with a density of 100 kg / m³. ３ A composition according to any one of claims 1 to 8, having a density less than [amount missing].

10. The composition according to any one of claims 1 to 8, wherein the flexible polyurethane foam exhibits at least one of the following: (i) acceptance in the British Standard BS 5852:2006 (Crib 5) test, and (ii) a Class 1 IM rating according to the UNI 9175 flammability test.