Polyurethane foam

Abstract

A foam forming composition for preparing a soft polyurethane foam, the foam forming composition comprising: a polyol component comprising one or more polyether polyols having a hydroxyl number of from 25 mg KOH / g to 100 mg KOH / g, as determined according to ASTM D4274, and having two to eight 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, the additive component being 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, the isocyanate component comprising one or more aromatic isocyanates. The composition excludes melamine and a halogen-containing flame retardant.

Description

[0001] Embodiments are directed to foam-forming compositions and flexible polyurethane foams made from such foam-forming compositions. Background Art

[0002] Polyurethane foams such as flexible polyurethane foams can be used for comfort applications such as mattresses, cushions, padding, fillings, or decorative furniture (e.g., to provide support and load-bearing). Such polyurethane foams typically include flame retardant additives. However, users of flexible polyurethane foams, such as consumers and manufacturers of bedding and furniture, increasingly require that such foams do not contain specific flame retardant (FR) additives, especially melamine and halogen-based compounds (such as fluorinated flame retardants, chlorinated flame retardants, and brominated flame retardants, including those known in the art). More and more regulations have phased out the use of melamine and halogen-containing flame retardant additives.

[0003] Although such flame retardant additives have been widely used in flexible polyurethane foams because they help enable the foam to 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 specified maximum weight loss test while exhibiting desirable foam mechanical and physical properties (such as high resilience and low compression set at 90%). Alternative flame retardant additives have been proposed, for example, publication number US2008 / 0157037 discloses a halogen-free polyurethane foam as part of a dryer seal assembly, which includes an intumescent flame retardant additive comprising ammonium polyphosphate (35 wt.% to 45 wt.%), melamine (35 wt.% to 45 wt.%) and pentaerythritol (15 wt.% to 25 wt.%). However, in the search for alternative compositions that are both halogen-free and melamine-free while still exhibiting good physical and mechanical properties, such compositions still require melamine. Summary of the invention

[0004] The embodiment can be realized by providing a foam-forming composition for preparing a flexible polyurethane foam, the foam-forming composition comprising: a polyol component including one or more polyether polyols having a hydroxyl value of 25 mg KOH / g to 100 mg KOH / g as determined according to ASTM D4274 and having two to eight hydroxyl groups per molecule; an additive component including ammonium polyphosphate and alkaline earth metal carbonate in a weight ratio of 1.3:1 to 6.5:1, the additive component being 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 including one or more aromatic isocyanates. The composition excludes (e.g., does not include, avoids using, etc.) melamine and halogen-containing flame retardants. DETAILED DESCRIPTION

[0005] According to an embodiment, the flexible polyurethane foam can exhibit improved performance in terms of fire resistance without the use of melamine and / or halogen-containing flame retardant (FR) additives (e.g., fluorine-, chlorine-, and bromine-based flame retardants). For example, the use of trichloropropyl phosphate TCPP is avoided. It has been found that the additive component in the foam-forming composition provides a flexible polyurethane foam with improved flame retardant effect, the additive component including ammonium polyphosphate (APP) and alkaline earth metal carbonate (MC) (e.g., essentially consisting of) in a ratio of 1.3:1 to 6.5:1 (e.g., 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.). Such additive components can exclude (e.g., do not contain) 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 to 50 parts (e.g., 8 to 40 parts) based on 100 parts (total weight) of the polyol component, e.g., including all polyols in the foam-forming composition and excluding any of the isocyanate component, the additive component, water, the catalyst, and the 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 also include water (e.g., as a chemical foaming agent), and can optionally include one or more other physical or chemical foaming agents. The foam-forming composition can also include one or more catalysts, such as amine and / or tin catalysts (e.g., tertiary amine catalysts). In addition, the foam-forming composition can include a surfactant, such as a silicone surfactant. In addition, the foam-forming composition can include one or more cell openers to help prepare light and soft open-cell foams, and / or one or more chain extenders and / or one or more cross-linking agents.

[0007] The polyurethane foam according to the embodiment can pass BS 5852 Crib 5 flammability test and / or can pass UNI 9175 flammability test, reaching 1M class rating. Further, including polyisocyanate polyaddition (PIPA) polyol in the foam-forming composition can further improve fire resistance. In addition, the foam-forming composition can have a wide range of uses, and can achieve improved fire resistance in a flexible polyurethane foam with an elasticity of 25% to 85% as determined according to ASTM-D3574-16 (2016). As used herein, the term "ASTM" refers to a publication of ASTM International, Conshohocken, Pa. As used herein, "UNI" refers to a publication of the Italian Organization for Standardization (Milan IT).

[0008] Flexible polyurethane foam includes foams of both conventional flexible foam and high elasticity foam. As used herein, the term "conventional flexible" polyurethane foam can refer to such foams, which can include or come from (a) a polyether polyol with a secondary hydroxyl group or mainly with a secondary hydroxyl group, such as being present in a polyol derived from propylene oxide (PO), and can include one or more isocyanates in an isocyanate component. As used herein, the term "high elasticity" (HR) flexible polyurethane foam can refer to such foams, which can include or come from a polyether polyol with a primary hydroxyl group (such as an ethylene oxide (EO) group), and can include one or more prepolymers made of methylene di(phenyl isocyanate) or MDI in (f) a polyisocyanate component. The wide formulation flexibility of foams and foam-forming compositions further allows the inclusion of additional polyols, such as polyester polyols and / or PIPA polyols.

[0009] The polyurethane foam can have a hardness less than or equal to 100 kg / m as determined according to ISO 845. 3 (For example, 10kg / m 3 Up to 90kg / m 3 , 20kg / m 3 Up to 70kg / m 3 , 25kg / m 3 Up to 60kg / m 3The flexible polyurethane foam can have an elasticity of 25% to 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 can exhibit one or more, or all, of the following: (i) a conformity 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, an extinguishing test time rating of less than 600 seconds, such as 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 Filling 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 Standards (BSI), London, UK, 2006).

[0010] For high resilience foam, the flexible polyurethane foam can have an elasticity of 25% to 85% or, for example, 55% or more as determined according to ASTM-D3574-16 (2016). Unless otherwise specified, the conditions of temperature and pressure are ambient temperature (21° C. to 24° C.), 50% relative humidity and standard pressure (1 atm).

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

[0012] The polyether polyol can comprise the reaction product or adduct of at least one initiator having two to eight 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 can be selected from: (i) a mixed feed polyether polyol having an ethylene oxide (EO) content of 0.3 wt.% to 40 wt.% 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 wt.% based on the total weight of all EO and PO in the polyether polyol; (iii) a propylene oxide (PO) polyether polyol capped with 10 wt.% to 25 wt.% 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, each polyurethane particle comprising at least two urethane bonds.

[0013] As used herein, the term "hydroxyl number" in units of mg KOH / g analyte refers to the amount of KOH required to neutralize acetic acid absorbed when one gram of analyte material is acetylated, as determined according to ASTM D4274. The term "average hydroxyl number" refers to the weight average of the hydroxyl numbers of a mixture of hydroxyl functional compounds. For example, a 50 / 50 mole % mixture of a PIPA polyol having a hydroxyl number of 80 and an all-propylene oxide (PO) polyether polyol (ii) having a hydroxyl number of 60 would have an average hydroxyl functionality of 0.5 (80) + 0.5 (60) or (40 + 30) or 70. As used herein, the term "hydroxyl equivalent weight" or "equivalent weight" or "EW" of a given polyether polyol or polyol refers to the calculated value as determined by the following formula: EW = 56,100 / hydroxyl number of a given polyol.

[0014] As used herein, the term "hydroxyl functionality" and other similar terms refer to the number of hydroxyl groups in the ideal formula of a given diol or polyol, without taking into account impurities or variability in the formula. The actual hydroxyl functionality of a given polyol may be lower than the nominal hydroxyl functionality for various reasons known in the art.

[0015] As used herein, the term "molecular weight" or "MW" of a given polyether polyol or polyol refers to the calculated value as determined by the following formula: MW = (56,100 / hydroxyl number) x nominal hydroxyl functionality of the polyol.

[0016] As used herein, unless otherwise indicated, the term "isocyanate index" or simply "index" refers to the ratio of the number of equivalents of isocyanate functional groups to the number of equivalents of active hydrogens (e.g., hydroxyl groups) in a given polyurethane-forming reaction mixture, multiplied by 100 and expressed numerically. For example, in a reaction mixture where the number of equivalents of isocyanate equals the number of equivalents of active hydrogens, the isocyanate index is 100. As used herein, the term "isocyanate-reactive group" refers to an active hydrogen, such as the hydrogen in a hydroxyl group.

[0017] As used herein, the term "isocyanate" refers to an isocyanate group-containing substance having one or more isocyanate functional groups, for example, an isocyanate-terminated prepolymer, a polyisocyanate, or a biuret, allophanate, isocyanurate, carbodiimide, dimer, trimer, oligomer or polymer prepared by reacting an isocyanate with one or more other compounds.

[0018] As used herein, the phrase "particle size" or "particle size diameter (PSD)" refers to the particle size diameter of a given material as determined by laser light scattering and is reported as the volume % of particles in a dispersion having the specified maximum particle diameter. As used herein, the phrase "wt %" means percent by weight.

[0019] 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, the isocyanate-reactive component comprising: (a) a polyol component comprising one or more polyols such as polyethers and / or PIPA polyols; and (b) an additive component comprising a combination of ammonium polyphosphate (APP) and alkaline earth metal carbonate (MC) (the weight ratio of APP:MC is 1.3:1 to 6.5:1); (c) potential 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 are free of melamine and halogen-containing flame retardants. The alkaline earth metal carbonate (MC) can include at least one selected from the group consisting of calcium carbonate, magnesium carbonate and barium carbonate.

[0020] The foam-forming composition can have a wide formulation window and includes compositions that form low-density, high-resilience polyurethane foams, blocky polyurethane foams with conventional elasticity, characterized by improved flame retardant properties. Flexible polyurethane foams can have improved flame retardant properties. The nature of the foam-forming composition can determine the formation of low or high-resilience foams. For example, high-resilience foams can be obtained from foam-forming compositions with more or only primary hydroxyl groups, such as ethylene oxide (EO) groups in condensed form, and / or in compositions with, for example, methyl di(phenyl isocyanate) (MDI) in condensed form. At the same time, conventional elastic foams can contain all secondary hydroxyl groups in condensed form, such as propylene oxide (PO) groups, or, for example, PO / EO mixed feed polyether polyols.

[0021] The polyol component includes one or more polyether polyols, one or more of which have a hydroxyl value of 25 mg KOH / g to 100 mg KOH / g (e.g., 28 mg KOH / g to 80 mg KOH / g) as determined according to ASTM D4274 and have two to eight hydroxyls per molecule (e.g., two to six). The one or more polyether polyols can have a weight average molecular weight of 1100 g / mol to 18000 g / mol (e.g., 2400 to 15000, 3000 to 10000, etc.). The polyether polyol composition can have an equivalent / hydroxyl of greater than 550 (e.g., at least 700, at least 1000, at least 1200, or at least 1500, and can be at most 2250, at most 2000, or at most 1800, etc.).

[0022] Such polyether polyols can be formed by an initiator having at least two hydroxyl groups. The nominal hydroxyl functionality or number of hydroxyl groups of each polyether polyol is equal to the number of hydroxyl groups in the initiator. Suitable initiators can have two to eight hydroxyl groups (e.g., 2 to 6 hydroxyl groups). Suitable polyether polyols that can be used as (a) one or more polyether polyols for preparing flexible polyurethane foams can be formed by co-initiated diol and triol initiators. Initiators can include, for example, glycerol, erythritol, pentaerythritol, diglycerol, sorbitol, sucrose, sugar alcohols, and other polyols. Examples of diol initiators include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, diethylene glycol, thiodiethanol, N-methyldiethanolamine, and dipropylene glycol. Examples of triol initiators can include glycerol, trimethylolpropane, and triethanolamine. Difunctional polyether polyols can be formed by only diol initiators; and if triol initiators are used, trifunctional polyether polyols can be obtained.

[0023] The polyol component can include at least one polyether polyol having a hydroxyl value of 30 mg KOH / g to 40 mg KOH / g.

[0024] The (a) polyether polyol in the polyol component of the foam-forming composition can be selected from any of the following:

[0025] (i) a mixed feed polyether polyol having 1 wt.% to 40 wt.% (e.g., 5 wt.% to 30 wt.%, 5 wt.% to 60 wt.%, 5 wt.% to 70 wt.%, 5 wt.% to 80 wt.%, 5 wt.% to 100 wt.%, 5 wt.% to 200 wt.%, 5 wt.% to 300 wt.%, 5 wt.% to 400 wt.%, 5 wt.% to 300 wt.%, 5 wt.% to 5 ...

[0026] 10wt.% to 30wt.%) of EO content and 60wt.% to 99wt.% (e.g.,

[0027] 70wt.% to 95wt.%, 70wt.% to 90wt.%) of PO content;

[0028] (ii) Polyether polyols, based on polyether polyols (propylene oxide (PO) polyether polyols (ii))

[0029] The total weight of all EO and PO in the polyether polyol is 100 wt.% PO content;

[0030] (iii) PO polyether polyol capped with 10 wt.% to 30 wt.% EO based on the total weight of all EO and PO in the polyether polyol (ethylene oxide (EO) capped propylene oxide (PO) polyether polyol (iii));

[0031] (iv) a PIPA polyol dispersion of polyurethane and / or polyurethane-urea particles in a polyol carrier (a polyisocyanate polyaddition (PIPA) polyol). For example, the PIPA polyol can be a dispersion of polyurethane and / or polyurethane-urea particles in a carrier polyol, wherein the carrier polyol has an average molecular weight of 200 g / mol to 12000 g / mol (e.g., 400 g / mol to 6000 g / mol) and an average of at least two hydroxyl groups per molecule.

[0032] The polyol component can include a mixture of two or more polyols, such as 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-terminated PO polyether polyol (iii); or a mixture of a PO polyether polyol (ii) and an EO-terminated PO polyether polyol (iii). Optionally, a PIPA polyol. For example, (a) one or more polyether polyols include a mixture of (v) (iv) PIPA polyols in condensed form with any one or more of polyether polyols (i), (ii) or (iii), and the mixture includes 10 wt.% to 99 wt.% (e.g., 20 wt.% or more) of (iv) PIPA polyol in condensed form. The polyol component can include a mixture of a PIPA polyol or a (iv) PIPA polyol and a polyether polyol, wherein the mixture has an average hydroxyl value of 25 to 100 (e.g., 28 to 75) as determined according to ASTM D4274.

[0033] The (a)(iv) (PIPA) polyol for use in the foam forming composition can comprise a dispersion of polyurethane particles dispersed in a polyether polyol carrier. Suitable PIPA polyols can be prepared via known polymerization of an excess of (d1) polyether polyol with (d2) a compatible seed polyol and (D3) a co-reactant polyol in the presence of (d4) one or more polyisocyanates (such as a diisocyanate), such as disclosed in US 2014 / 0051778 A1 to Cookson et al. The PIPA polyol dispersion can be prepared by forming a reaction mixture under shear and reacting it to advance the PIPA polyol until the exotherm of a uniform dispersion ceases. Thus, the (a)(v) PIPA polyol can be the product of a reaction mixture of an excess of (d1) a polyether polyol carrier (such as one or more propoxylated or oxyethylene terminated polyether polyols having a molecular weight MW of 200 g / mol to 6000 g / mol and an average hydroxyl functionality of di- or tri-) with (d2) a compatible seed polyol and (d3) one or more co-reactant polyols (such as triethanolamine (TEOA) or diethanolamine (DEOA)) in the presence of (d4) one or more polyisocyanates (e.g., aromatic polyisocyanates).

[0034] For polyether polyols suitable as (d1), the carrier in (a)(iv) PIPA polyol can be any known polyether polyol known in the art having two to eight hydroxyl groups and a MW of up to 6000 g / mol. Including, 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 polyol having an average of 2 to 8 hydroxyl groups. Examples of suitable (d1) polyether polyols can include, for example, oxyethylene terminated polyols, can include glycerol initiated oxyethylene terminated poly(propylene oxide) copolymer triols, the copolymer triols having 10 wt.% to 19 wt.% oxyethylene in the alkylene oxide feed and having a hydroxyl value of 45 mg KOH / g to 80 mg KOH / g.

[0035] A suitable amount of total (d1) polyether polyols in the PIPA polyol can be in the range of 60 wt.% to 99 wt.% (e.g., 75 wt.% to 88.5 wt.%) based on the total weight of reactants used to prepare the PIPA polyol (dispersion), wherein all total wt.% add up to 100%. Most of the polyether polyols in the PIPA polyol can serve as the carrier phase in the dispersion.

[0036] Suitable (d2) compatible seed polyols for use in preparing (a)(iv) PIPA polyols can be PIPA seeds formed by reacting at least one (d4) aromatic isocyanate in the presence of an excess of a polyol (such as a polyether polyol) in a polyol mixture comprising: (i) any of a propylene oxide polyol, or an ethylene oxide terminated propylene oxide polyol, or an alkylene oxide triol initiated polyol containing from 1 wt.% to 30 wt.% of ethylene oxide; and (ii) one or more co-reactant polyols having nitrogen or phosphorus atoms and a molecular weight (MW) of up to 400 (e.g., up to 300), wherein the polyol mixture comprises at least 70 wt.% of (i) the propylene oxide polyol, the ethoxylated or ethylene oxide terminated propylene oxide polyol, or the alkylene oxide triol initiated polyol. In order to provide seeds that can be used to prepare high elastic foam, the polyol mixture can include polyols having at least 45wt.% (e.g., at least 75wt.%, at least 80wt.%, etc.) of hydroxyl groups as primary hydroxyl groups in the polyol mixture. In order to provide seeds that can be used to prepare conventional elastic foam, the polyol mixture can include polyols having at least 70wt.% (e.g., at least 85wt.%) of hydroxyl groups as secondary hydroxyl groups in the polyol mixture. The isocyanate index can be kept below 100 to keep the coreactant that forms PIPA present in the seed polyol. At least one polyisocyanate in the reaction for forming the (d2) seed polyol can be used to provide a composition having an isocyanate index of 50 to less than 100.

[0037] A suitable amount of (d2) one or more compatible seeds can be in the range of less than 5 wt.% (e.g., 2 wt.% to 4 wt.%) based on the total weight of the reactants used to prepare the PIPA polyol, wherein all total wt.% of all reactants used to prepare the PIPA polyol add up to 100%.

[0038] For PIPA polyols, (d3) one or more co-reactant polyols can be diols or triols or oligoether diols having a molecular weight of 400 or less, such as triethanolamine (TEOA) or diethanolamine (DEOA). Suitable co-reactant polyols (d3) can include diols, such as diols having a molecular weight of 62 to 400. Examples include alkane polyols, such as diols, such as ethylene glycol, propylene glycol, hexamethylene glycol, low molecular weight alcohols containing ether groups, such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol or butanediol; high functionality alcohols, such as polyglycerol; and alkanolamines, such as monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, 2-(2-aminoethoxyethanol), diisopropanolamine, TEOA, DEOA, and mixtures thereof.

[0039] A suitable amount of (d3) one or more co-reactant polyols can be in the range of 0.2 wt.% to 6 wt.% (e.g., 0.5 wt.% to 5 wt.%) based on the total weight of reactants used to prepare the (a)(iv) PIPA polyol, wherein all total wt.% used to prepare the PIPA polyol add up to 100%.

[0040] For the foam-forming composition, the (a)(iv) PIPA polyol can have a solid particle content of 1 wt.% to 40 wt.%, or 11.5 wt.% to 25 wt.%, or 5 wt.% to 15 wt.%, based on the total weight of the PIPA polyol. The particles can be uniformly distributed in the polyol carrier as a dispersion, and can have a particle size diameter (PSD) as determined by laser light scattering: 90% by weight of the particles in the dispersion have a maximum PSD of 0.1 μm to 10.0 μm (e.g., 0.2 μm to 5.0 μm, 0.2 μm to 2.5 μm).

[0041] The polyol carrier in each PIPA polyol can depend on the foam application in which the polyol carrier is used.The lower molecular weight polyols (ii) can be used as carriers in PIPA polyols suitable for making conventional foams and viscoelastic foams.

[0042] The polyol component of the foam-forming composition can further comprise an additional polyol, such as, for slabstock foam, a glycerol initiated ethylene oxide and propylene oxide mixed feed polyol having a MW of 5000, an EO content of 74 wt.%, and an OHn of 33. If used, a suitable amount of (g) one or more cell openers can range from 0.05 wt.% to 1 wt.% (e.g., 0.1 wt.% to 0.6 wt.%) based on the total weight of the polyol component, wherein all total wt.% add up to 100.

[0043] The polyol component of the foam-forming composition can additionally include (h) one or more diol extenders. The diol extender can include any diol, for example, ethylene glycol or butanediol. Such (h) diol extenders can be included in the foam-forming composition as reactants that reduce the viscosity of the polyol component and also ultimately increase the molecular weight of the polyurethane reaction product made from the diol extender. If used, a suitable amount of (h) one or more diol extenders can be in the range of 1 wt.% to 8 wt.% (e.g., 1.5 wt.% to 6 wt.%) based on the gross weight of the polyol component, wherein all total wt.% add up to 100%.

[0044] The polyol component of the foam-forming composition can further comprise (j) one or more polyester polyols, which may be desirable to improve the mechanical properties of the flexible polyurethane foam made therefrom or its compatibility with further materials or substrates.

[0045] The polyol component of the foam-forming composition can additionally include (1) one or more crosslinking agents. The crosslinking agent can include any triol or other low MW molecule having a hydroxyl functionality greater than 3, such as glycerol, or a glycerol derivative obtained by alkoxylating glycerol with PO to a hydroxyl value of about 620. Such (1) crosslinking agents can be included in the foam-forming composition as reactants that reduce the viscosity of the polyol component and also ultimately increase the molecular weight of the polyurethane reaction product made from the crosslinking agent. If used, a suitable amount of (1) one or more crosslinking agents can be in the range of 1 wt.% to 8 wt.% (e.g., 1.5 wt.% to 6 wt.%) based on the total weight of the polyol component, wherein all total wt.% add up to 100%.

[0046] Isocyanate component The foam-forming composition comprises one or more isocyanates, such as aromatic isocyanates. Suitable isocyanates used in the foam-forming composition may be those known in the art, such as being able to comprise aromatic polyisocyanates, prepolymers, or mixtures of two or more of these. Examples of available isocyanates include methylene diphenyl-based isocyanates (such as MDI and isocyanate-terminated prepolymers made using MDI) and toluene-based isocyanates (such as TDI and isocyanate-terminated prepolymers made using TDI).

[0047] In the foam-forming composition and the method for preparing the same, the suitable amount of the isocyanate component can be within the range of the amount required to provide the foam-forming composition with an isocyanate index of 50 to 150 (e.g., 55 to 125, etc.). The foam-forming composition provides a flexible polyurethane foam that exhibits at least one or both of the following: (i) a conformity assessment rating in the overall flame Crib 5 British Standard BS 5852:2006 (Crib 5) test; or (ii) a Class 1 IM rating according to the UNI 9175 flammability test. (b) The additive combination does not contain a halogen-containing flame retardant and does not contain melamine. Further, the polyol component of the foam-forming composition can include (c) water or at least one blowing agent, or both. Water and blowing agents are typically combined with the polyol component and separated from the polyisocyanate component. Exemplary blowing agents include chemical blowing agents (such as water and formic acid) and 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 wt. % to 7.0 wt. % (eg, 2.5 wt. % to 5.0 wt. %) based on the total weight of the polyol component.

[0048] In order to better drive the formation of flexible polyurethane foam or polyurethane formation, or both, the isocyanate reactive component of the foam-forming composition can additionally include: (e) one or more catalysts, such as 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, for example, a zinc salt or a zinc fatty acid catalyst, a tin salt or a bismuth salt and / or a tertiary amine (such as, for example, triethylenediamine or bis-dimethylaminoethyl ether). Based on the total weight of the isocyanate reactive component, the suitable total amount of (e) one or more catalysts can be in the range of 0.01 wt.% to 5 wt.% (e.g., 0.5 wt.% to 1.0 wt.%, 0.01 wt.% to 0.2 wt.%, etc.).

[0049] The isocyanate-reactive component can include other additives known in the art, such as at least one foam stabilizer, such as a silicone surfactant, which helps stabilize the bubbles formed during the foaming process, for example; a filler, such as talc; a pigment; a colorant; a reinforcing agent, such as fibers or microfibers; a biocide; a preservative; an antioxidant; and / or an autocatalytic polyol.

[0050] The method for preparing a flexible polyurethane foam with improved flame retardant properties can include any method for forming foam using a foam-forming composition. The method can include, for example, forming an isocyanate-reactive component comprising an additive combination of one or more polyether polyols or mixtures thereof and ammonium polyphosphate flame retardant and calcium carbonate; and mixing the polyol component with the isocyanate component. The mixing can also include mixing the isocyanate-reactive component with the isocyanate component to form a reactive mixture. The reaction mixture can then be poured into a mold (such as an open mold or a closed mold). Molding using closed molding or molding under pressure promotes the formation of more resilient foams, and / or can be free-rising. Alternative methods can include the reaction of various components (such as isocyanates, polyols, catalysts, and additives), which are processed according to a continuous block foam production method and are typically used in the production of conventional flexible foams.

[0051] Flexible polyurethane foams can be used in bedding and furniture, or fillings, such as pillows, mattresses, and cushions for chairs and sofas, and layers therein, such as mattress topper in Euro-style mattresses.

[0052] Examples :

[0053] The following examples illustrate exemplary embodiments. Unless otherwise stated, all temperatures are ambient temperatures (21° C.-24° C.), all pressures are 1 atmosphere, and relative humidity (RH) is 35%. Although the numerical ranges and parameters setting forth the broad scope of the invention are approximate, the numerical values ​​set forth in the specific examples are reported as accurately as possible. Any numerical value inherently contains certain determined errors that are necessarily caused by standard variations present in its respective test measurements.

[0054] Materials used in the Examples and not otherwise defined below are set forth in Table 1 below. Abbreviations used in the Examples include: APP: ammonium polyphosphate; CC: calcium carbonate; CLD: compression load deflection; DEOA: diethanolamine; EO: ethylene oxide; FR: flame retardant additive; HR: high elasticity; OHn: hydroxyl number; PIPA: polyisocyanate polyaddition; PO: propylene oxide; SO: stannous octoate.

[0055] Table 1: Materials

[0056]

[0057]

[0058] In Table 1 above, isocyanate 1 is a prepolymer formed by the reaction of an isocyanate component with a polyol component. The isocyanate component is added to a reactor, and the reaction temperature is brought to about 70°C under stirring under a nitrogen atmosphere. The polyol components (polyol G and polyol H) are premixed and then gradually added to the reactor at a sufficiently low rate to allow removal of the exothermic heat generated by the reaction of the isocyanate groups with the hydroxyl groups. After the addition of the polyol components is completed, the prepolymer is digested by stirring it at about 70°C while monitoring the NCO content according to the method shown in ASTM D5155. When the NCO content reaches a target NCO value of 30wt.% based on the total amount of the prepolymer, the prepolymer formation is considered complete.

[0059] Conventional elastic open box foam forming: To form the foams shown in Tables 5 and 6 below, free-rise foams were formed in a simplified manner to simulate a block-like flexible foam production process by hand mixing and pouring in an open cardboard box for laboratory use. All stages of the foaming process were carried out in a fume hood or under a fume hood. All chemicals used in the formulation were balanced at room temperature before use. Foams were prepared using an open top 27-liter cardboard box (30×30×30 cm). When forming the polyol component, the polyol was accurately weighed into a 2.2-liter plastic bucket, and a surfactant and water were added to the polyol. Any solid material was then slowly added to the polyol while being manually mixed to avoid agglomeration. When more than one solid additive was present, the solid additives were mixed together before being introduced into the polyol component. The amine catalyst was then introduced into the polyol component. If used, the gelling catalyst stannous octoate (SO) was weighed into a moistened and tared syringe and placed on the side. The required amount of polyisocyanate was weighed into a separate plastic container, which was rinsed with isocyanate before taring and weighed after dispensing the polyisocyanate into the open box to compensate for any polyisocyanate remaining in the container after dispensing.

[0060] When hand mixing to form the polyol component and subsequently to form the two-component composition, the mixer speed was set to 2000 rpm; and the following mixing procedure was used:

[0061] (i) Start the stopwatch and rise analysis (foam height measurement) software;

[0062] (ii) at 5 seconds, begin mixing the polyol component with water and surfactant, and add solid additives, and then add the amine catalyst;

[0063] (iv) at 30 seconds, adding a gelling catalyst (SO) to the polyol component;

[0064] (v) at 40 seconds, the isocyanate was added (this was considered to be t0 or the time when the reaction started);

[0065] as well as

[0066] (vi) At 50 seconds, stop the mixer and pour the mixture into a box.

[0067] Record the complete rise and blow-off times. After 5 minutes, when the foam is fully formed, transfer the foam to an oven set at 140°C to further cure it for 5 minutes. Remove the foam from the box and place it overnight in a fume hood at ambient temperature to complete the reaction. The resulting foam is crushed with a mechanical roll crusher to open the internal pores. The physical properties of all conventional elastic foam materials are tested, as shown in Table 2 below.

[0068] Highly resilient molded foam formation The foams shown in Table 3, Table 4A and Table 4B below were prepared using a Cannon A 40 high pressure molding machine (Cannon USA, Cranberry Township, PA) equipped with an FPL mixing head with a 14 mm piston diameter and preset to specified settings. The mold was heated by water recirculation and treated with an anhydrous release agent. The two-component foam forming mixture was poured into the mold, which was then closed while the mixture reacted inside the mold. The resulting foam was then demolded after the time period specified below. After demolding, the foam was broken with a mechanical roller to open the internal pores. The molding machine and method were set to:

[0069]

[0070]

[0071] Test Method : In the following examples, the following test methods were used. The standard deviations of all data were within acceptable limits.

[0072] UNI 9175–1 Category IM : Small flame test.

[0073] BS5852 Ignition Source 5 (Crib5) : In the Crib 5 test, white fabric is applied for covering. Unless otherwise specified, each result is the average of two tests. If self-extinguishing occurs within 10 minutes and the foam weight loss remains <60g during the test, the result is generally "pass". If the Crib 5 test results in > If the weight loss is less than 60 g or it fails the self-extinguishing test, the overall result is reported as "FAIL".

[0074] Table 2: Foam test methods and standards

[0075]

[0076] In the foams shown in Table 3, Table 4A, Table 4B, Table 5 and Table 6 below, all materials except the isocyanate comprise part of the polyol component.

[0077] Table 3: High Resilience Molded Foam with Class 1 IM Flammability Test Results

[0078]

[0079]

[0080] *- indicates comparative example; 1: not applicable; 2. pbw = parts by weight.

[0081] In Table 3, all foams were made in molds having dimensions of 45 cm x 45 cm x 7.5 cm (15.1 liters) and 45 cm x 30 cm x 7.5 cm (10.1 liters) to prepare the foam specimens specified in each listed test. As shown in Table 3 above, in the high resilience (HR) foams of Comparative Examples 1 and 2 (CE-1 and CE-2) containing either APP or CC, both foams failed the Class 1 IM test. The CE-3 foam containing a 1:1 (w / w) additive combination of APP and CC (solids) at 10 wt.% of the solids in the isocyanate-reactive component (so that the combination of polyol, water, APP, CC and other additives, excluding only the isocyanate component) also failed the Class 1 IM flammability test. Meanwhile, the foam of Inventive Example 1 containing a 4:1 (w / w) additive combination blend of APP and CC (solids) at 10 wt.% of the solids in the isocyanate-reactive component passed the Class 1 IM flammability test.

[0082]

[0083]

[0084] The foams described in Tables 4A and 4B were made in molds having dimensions 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 contained melamine at a solid content of 21 wt.% in the isocyanate reactive component. CE-1A represents a comparative standard for combustion performance. The foam of Inventive Example 1A having an APP / CC weight ratio of 4 at a solid content of 21 wt.% in the isocyanate reactive component passed the Crib 5 test. Meanwhile, the foams of Comparative Examples CE-2A and CE-3A (loading APP or CC, respectively, at a solid content of 21 wt.% in the isocyanate reactive component) failed the Crib 5 test. Further, the foams of Inventive Examples 2A and 3A having additive combinations of solid contents of 25 wt.% and 28 wt.%, respectively, in the isocyanate reactive component passed the Crib 5 test. Higher loadings of the same inventive additive combination further improved fire resistance when the foam weight loss changed from 29.7 wt.% for Inventive Example 1A to 20 wt.% for Inventive Example 2A. Still further, the foams of Inventive Examples 4A and 5A, which had an APP / CC weight ratio of 4 at 21 wt.% solids in the isocyanate reactive component and also contained PIPA polyol, passed the Crib 5 test. In addition, the foam of Inventive Example 3A had improved compression set, demonstrating that high performance foam materials can have higher loadings of additive components.

[0085] The foams prepared in Table 5 below were allowed to free rise in an open top 30 cm x 30 cm box. As shown in Table 5 below, the foam of Comparative Example CE-1B includes an open box foam loaded with melamine representative of the prior art. The foams of Comparative Examples CE-2B and CE-3B, which include foams loaded with CC or APP, each failed the Class 1 IM flammability test.

[0086] Compared to Comparative Examples CE-2B and CE-3B, the foams of Inventive Examples 1B, 2B, 3B, and 4B, which have the same total additive package content (19 wt.% solids in the isocyanate reactive component) as the foam of Comparative Example CE-1B, all passed the UNI 9175 test using the Class 1 IM rating at APP / CC weight ratios of 1.5 to 1.86 to 2.57 to 4. Meanwhile, 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 using the Class 1 IM rating. In addition, the foams of Inventive Examples 1B, 2B, 3B, and 4B show increased compression set at 90% when they contain relatively more APP.

[0087] Table 5: Open box foam with normal elasticity and test results 2

[0088]

[0089] *- indicates comparative example; 1. not applicable; 2. formulation amount is expressed per 100 parts by weight of polyol component.

[0090] Table 6. Open box foams with conventional elasticity and test results 4

[0091]

[0092]

[0093] *- indicates comparative example; 1. 2 tests and 1 pass; 2. Results of failed tests; 3. From PIPA polyol (Polyol E); 4. Formula amounts are expressed per 100 parts by weight of the polyol component.

[0094] The foams in Table 6 above were allowed to rise freely in an open top 30 cm x 30 cm box. All of the inventive examples 1C, 2C, 3C, 4C, 5C and 6C in Table 6 passed the UNI 9175 flammability test using a Class 1 IM rating. All foams contained a weight ratio of APP:CC of 4. In inventive example 1C, the foam contained polyol A (100 wt.% propylene oxide units based on total alkylene oxides). In addition to polyol A, the foams in inventive examples 2C, 3C, 4C and 5C also contained an increased amount of PIPA polyol (polyol E), demonstrating that PIPA polyols (such as an amount of 30 wt.% or more of all polyols, or more preferably an amount of 40 wt.% of all polyols) enable the foam to pass a more stringent flammability test, such as the Crib 5 test / BS 5852 ignition source 5. Further, the present examples 1C, 2C, 3C, 4C and 5C show that the flame retardant flexible polyurethane foam according to the exemplary embodiment can include block foam and other flexible foams having an elasticity of 30% to 55% as determined according to ASTM-D3574-16 (2016). Therefore, the scope of the embodiment is not limited to high elastic foam.

[0095] Referring to Table 7 below, the examples describe foams with different carbonate essences. Inventive Examples 1D, 2D, and 3D describe foam formulations having calcium carbonate (CC), magnesium carbonate (MgC), or barium carbonate (BaC), respectively, as the alkaline earth carbonate source. These foams passed the Crib 5 test. However, Comparative Examples CE-1D and CE-2D describe foams having zinc carbonate (ZnC) or sodium carbonate (NaC), and these foams did not pass the Crib 5 test.

[0096] Table 7. Typical foam formulations for blocks .

[0097]

[0098]

[0099] *From Polyol E

[0100] **Melamine, mixture of APP + carbonate (CC, MgC, BaC, ZnC or NaC)

[0101] Referring to Table 7, alkaline earth metal carbonates (particularly magnesium carbonate, calcium carbonate, and barium carbonate) can achieve similar performance in combination with APP compared to other carbonates.

Claims

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

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

3. The composition of any one of claims 1 to 2, wherein the weight ratio is from 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 of any one of claims 1 to 4, wherein one of the one or more polyether polyols has a hydroxyl value of 30 to 40 mg KOH / g.

6. The composition of any one of claims 1 to 5, wherein the polyol component further comprises a PIPA polyol.

7. The composition of any one of claims 1 to 6, wherein the composition further comprises water, one or more catalysts and one or more surfactants.

8. The composition of any one of claims 1 to 7, wherein the foam-forming composition has an isocyanate index of 50 to 150.

9. The composition according to any one of claims 1 to 8, wherein the flexible polyurethane foam has a hardness as determined according to ISO 845 of less than 100 kg / m 3 density.

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

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