Foam formulations

Abstract

Embodiments of the present disclosure are directed towards foam formulations and methods for making and using the foam formulations.

Description

FOAM FORMULATIONS Field of Disclosure

[0001] This disclosure relates to foam formulations and methods for making and using the foam formulations. Background

[0002] Flexible polyurethane foam is used for a number of applications, including furniture molding applications, among others. Foam of this type is made by reacting a foam formulation that includes one or more isocyanates and one or more polyols. Summary

[0003] The present disclosure provides foam formulations including a formulated polyol composition comprising: a non-amine containing polyether polyol, wherein the non-amine containing polyether polyol is from 70 to 90 parts by weight, per 100 parts by weight of the formulated polyol composition, an alkali metal carboxylate, wherein the alkali metal carboxylate is from 0.01 to 0.1 parts by weight, per 100 parts by weight of the formulated polyol composition, and an amine containing alcohol, wherein the amine containing alcohol is from 10 to 30 parts by weight, per 100 parts by weight of the formulated polyol composition; and an isocyanate composition comprising diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, or a combination thereof, wherein the isocyanate composition includes from 19 to 25 parts of biuret oligomers based upon 100 parts of the isocyanate composition. Detailed Description

[0004] The foam formulations disclosed herein include an alkali metal carboxylate, an amine containing alcohol, and biuret oligomers. The foam formulations disclosed herein can advantageously be utilized to make a foam having desirable fire test properties, e.g., the foams pass fire test UNI 9175 C.S.E. RF4 and provide a Class 1 IM rating. In some locales, e.g., Italy, polyurethane foams must pass fire test UNI 9175 C.S.E. RF4 for utilization for public furniture, such as cinema, busses, and public offices, among others. Further, foams made from the foam formulations disclosed herein can advantageously have a compression set at 50% no greater than 14%, which is desirable for a number of applications. The foam formulations disclosed herein can be utilized to make a flexible polyurethane foam.

[0005] A number of previous polyurethane foams have passed fire test UNI 9175 C.S.E. RF4. However, these previous foams incorporate solid and / or liquid flame retardants such as melamine, expandable graphite, halogenated flameretardants, and / or phosphorous containing flame retardants. Utilizing solid and / or liquid flame retardants is undesirable for a number of applications.

[0006] The foam formulations disclosed herein include a formulated polyol composition and an isocyanate composition. The formulated polyol compositions include the alkali metal carboxylate, an amine containing alcohol. The isocyanate composition includes the biuret oligomers.

[0007] The alkali metal of the alkali metal carboxylate may include lithium, sodium, or potassium. The carboxylate may include 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. One or more embodiments provide that the carboxylate is a two-carbon carboxylate. One or more embodiments provide that the carboxylate is a monocarboxylate. One or more embodiments provide that the alkali metal carboxylate is potassium acetate. The alkali metal carboxylate may be prepared by a known process. The alkali metal carboxylate may be obtained commercially, e.g., as part of commercial composition. One example of a commercial alkali metal carboxylate is DABCO K2097, available from Evonik and containing 30% potassium acetate in diethylene glycol. The alkali metal carboxylate may provide various attributes, such as trimerization catalyzation, for instance, which is generally not utilized for flex foam applications.

[0008] The alkali metal carboxylate may be from 0.01 to 0.1 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 0.01 to 0.1 parts are included; for example, the alkali metal carboxylate may be from a lower limit of 0.01, 0.02, or 0.03, parts to an upper limit of 0.1, 0.09, 0.08, or 0.07 parts per 100 parts by weight of the formulated polyol composition.

[0009] As used herein, “amine containing alcohol” refers to an alcohol containing at least one tertiary amine group. The amine containing alcohol may also be referred to as an “autocatalytic alcohol”. For instance, the amine containing alcohol may have from 1 to 8 tertiary amine groups. All individual values and subranges from 1 to 8 are included; for example, the amine containing alcohol have from a lower limit of 1, 2, or 3 tertiary amine groups to an upper limit of 8, 7, or 6 tertiary amine groups.

[0010] The amine containing alcohol may have a hydroxyl number from 15 to 200 mg KOH / g. Hydroxyl number may be determined according to ASTM D4274.

[0011] The amine containing alcohol may have a hydroxyl functionality of from 1 to 8. All individual values and subranges from 1 to 8 are included; for example, the amine containing alcohol have a hydroxyl functionality from a lower limit of 1, 2, or 3 to an upper limit of 8, 7, or 6. One or more embodiments provide that theamine containing alcohol has a hydroxyl functionality of 4. As used herein, “functionality” refers to an average functionality, unless stated otherwise.

[0012] The amine containing alcohol may be made by a known process. The amine containing alcohol may be obtained commercially. The amine containing alcohol may be an aliphatic polyether polyol. The amine containing alcohol, e.g., amine containing aliphatic polyether polyols, may be made as described in U.S. patent publication 2011 / 0319572. The amine containing alcohol may be made by alkoxylation of at least one tertiary amine containing initiator molecule.

[0013] The amine containing alcohol may be made with an oligomer of ethylene oxide (EO), an oligomer of propylene oxide (PO) or an ethylene oxide endcapped polyether polyol, such as a polyoxyethylene-capped polyoxypropylene polyol, or an EO endcapped PO, for instance. The polyether polyol may be made from 100% PO, or a mixture of EO and PO containing from 10 to 20 wt.% of EO, based on a total weight of alkylene oxides used to form the polyether polyol.

[0014] Examples of tertiary amine initiators include, but are not limited to, bis- 3-aminopropyl methyl amine, a dimer thereof, or a trimer thereof; propoxylated bis-3- amino-propyl methyl amine, a dimer thereof, or a trimer thereof; 3,3'-diamino-N- methyldipropylamine, 2,2'-diamino N-methyldiethylamine, 2,3-diamino-N-methyl- ethyl-propylamine, an aminopropyl-terminated 2-propenenitrile-methanamine polymer having 8 or fewer amine groups, or a mixture thereof. Examples of suitable tertiary amines may have one of the following formulae:.

[0015] In the case of the later tertiary amine of formula shown above, the amine containing polyol may comprise an adduct, such as an alkylene oxide adduct formed with the amine hydrogens of the tertiary amine.

[0016] Other examples of suitable tertiary amine initiators for making the amine containing polyols include, for example, any of triethanoldiamines, triethylene tetramines, or N,N-dimethyl-tris (hydroxymethyl)aminomethane. Other examples of suitable tertiary amine initiators may be found, for example, in US patent application publication nos. US2004 / 0242832 A1 or US2008 / 0096993 A1.

[0017] One example of an amine containing alcohol is a bis-3-aminopropyl methyl amine-initiated propoxylated / ethoxylated polyol, such as one made of a polyether diol of EO and PO containing, in condensed form, an EO amount of 17.5 wt%, based on the total weight of alkylene oxides used to form the amine containing polyol, having an hydroxyl equivalent weight (HEW) of 1700, and a hydroxyl functionality of 4 (CAS no.346426-38-83). Another example of an amine containing alcohol is an ethoxylated, propoxylated and hydrogenated, aminopropyl-terminated 2-propenenitrile-methanamine polymer (of formula IV, above) having an hydroxyl equivalent weight (HEW) of 1547, a hydroxyl functionality of 4 and an EO content of 16.6 wt.%, based on the total weight of alkylene oxides used to form the amine containing l aliphatic polyether polyol (Cas no.2055838-16-7). Examples of suitable amine containing polyols commercially available are a number of VORANOL Polyols available from The Dow Chemical Company.

[0018] The amine containing alcohol may be from 10 to 30 parts by weight, per 100 parts by weight of the formulated polyol composition.

[0019] The formulated polyol composition can include a non-amine containing polyether polyol, e.g., a polyol that does not include a tertiary amine group. The non-amine containing polyether polyol can be from 70 to 90 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 70 to 90 parts are included; for example, the non-amine containing polyether polyol may be from a lower limit of 70, 75, or 80 parts to an upper limit of 90, 87, or 85 parts per 100 parts by weight of the formulated polyol composition. The non-amine containing polyether polyol can be a glycerine initiated ethylene oxide endcapped polyether polyol, a sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol, a high ethylene oxide polyether polyol, or a combination thereof, among other non-amine containing polyether polyols. Glycerine initiated ethylene oxide endcapped polyether polyols, sorbitol and glycerine initiated ethylene oxide endcapped polyether polyols, and high ethylene oxide polyether polyols are discussed further herein.

[0020] The formulated polyol composition can include a non-amine containing polyether polyol that is a glycerine initiated ethylene oxide endcapped polyether polyol. The glycerine initiated ethylene oxide endcapped polyether polyol can be from 15 to 85 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 15 to 85 parts are included; for example, the glycerine initiated ethylene oxide endcapped polyether polyol may be from a lower limit of 5, 8, or 10 parts to an upper limit of 85, 80, or 75 parts per 100 parts by weight of the formulated polyol composition.

[0021] The glycerine initiated ethylene oxide endcapped polyether polyol may have a HEW from 250 to 4000. All individual values and subranges from 250 to 4000 are included; for example, the glycerine initiated ethylene oxide endcapped polyether polyol can have a HEW from a lower limit of 250, 5001000, or 1500 to an upper limit of 3500, 3000, 2500, or 2250.

[0022] The glycerine initiated ethylene oxide endcapped polyether polyol may have a hydroxyl functionality of from 2 to 8. All individual values and subranges from 2 to 8 are included; for example, the glycerine initiated ethylene oxide endcapped polyether polyol have a hydroxyl functionality from a lower limit of 2 or 3 to an upper limit of 8, 7, or 6. One or more embodiments provide that the glycerine initiated ethylene oxide endcapped polyether polyol has a hydroxyl functionality of 3.

[0023] The glycerine initiated ethylene oxide endcapped polyether polyol may have an ethylene oxide (EO) content from 10 to 35 wt%, based on a total weight of alkylene oxides used to make the glycerine initiated ethylene oxide endcapped polyether polyol. All individual values and subranges from 10 to 35 wt% are included; for example, the glycerine initiated ethylene oxide endcapped polyether polyol can have an EO content from a lower limit of 10, 12, or 15 wt% to an upper limit of 35, 30, or 25 wt% based on the total weight of alkylene oxides used to make the glycerine initiated ethylene oxide endcapped polyether.

[0024] The glycerine initiated ethylene oxide endcapped polyether polyol may be made by a known process. The glycerine initiated ethylene oxide endcapped polyether polyol may obtained commercially. A commercial example of the glycerine initiated ethylene oxide endcapped polyether polyol is available from The Dow Chemical Company, for instance.

[0025] The formulated polyol composition can include a non-amine containing polyether polyol that is a sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol. The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol can be from 15 to 85 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 15 to 85 parts are included; for example, the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may be from a lower limit of 5, 8, 10, or 20 parts to an upper limit of 85, 80, 75, or 50 parts per 100 parts by weight of the formulated polyol composition.

[0026] The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may have a HEW from 250 to 4000. All individual values and subranges from 250 to 4000 are included; for example, the sorbitol and glycerineinitiated ethylene oxide endcapped polyether polyol can have a HEW from a lower limit of 250, 5001000, or 1500 to an upper limit of 3500, 3000, 2500, or 2250.

[0027] The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may have a hydroxyl functionality of from 2 to 9. All individual values and subranges from 2 to 9 are included; for example, the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol can have a hydroxyl functionality from a lower limit of 2 or 3 to an upper limit of 9, 8, 7, or 6.

[0028] The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may have an ethylene oxide (EO) content from 5 to 35 wt%, based on a total weight of alkylene oxides used to make the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol. All individual values and subranges from 5 to 35 wt% are included; for example, the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol can have an EO content from a lower limit of 5, 10, or 15 wt% to an upper limit of 35, 30, or 25 wt% based on the total weight of alkylene oxides used to make the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol.

[0029] The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may be made by a known process. The sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol may obtained commercially. A commercial example of the sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol is available from The Dow Chemical Company, for instance.

[0030] The formulated polyol composition can include a non-amine containing polyether polyol that is a high ethylene oxide (EO) polyol. As used herein, “high ethylene oxide” polyol refers to a polyol that has an ethylene oxide content of at least 55 wt%. The high EO polyol can be utilized as a cell opener. The high EO polyol can be a polyether polyol. The high EO polyol can be glycerine initiated. The high EO polyol can be a glycerine initiated ethylene oxide / propylene oxide (EO / PO) polyether polyol. The high EO polyol can be from 0.2 to 10 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 0.2 to 10 parts are included; for example, the high EO polyol l may be from a lower limit of 0.2, 0.5, 0.8, or 1 parts to an upper limit of 10, 8, 5, or 3 parts per 100 parts by weight of the formulated polyol composition.

[0031] The high EO polyol may have a HEW from 250 to 4000. All individual values and subranges from 250 to 4000 are included; for example, the high EO polyol can have a HEW from a lower limit of 250, 5001000, or 1500 to an upper limit of 3500, 3000, 2500, or 2000.

[0032] The high EO polyol may have a hydroxyl functionality of from 2 to 8. All individual values and subranges from 2 to 8 are included; for example, the high EO polyol can have a hydroxyl functionality from a lower limit of 2 or 3 to an upper limit of 8, 7, 6, or 5.

[0033] The high EO polyol may have an ethylene oxide (EO) content from 55 to 95 wt%, based on a total weight of alkylene oxides used to make the high EO polyol. All individual values and subranges from 55 to 95 wt% are included; for example, the high EO polyol can have an EO content from a lower limit of 55, 65, or 70 wt% to an upper limit of 95, 85, or 80 wt% based on the total weight of alkylene oxides used to make the high EO polyol.

[0034] The high EO polyol may be made by a known process. The high EO polyol may obtained commercially. A commercial example of the high EO polyol is available from The Dow Chemical Company, for instance.

[0035] The formulated polyol composition can include a surfactant. Surfactants for use in the preparation of polyurethane foams are well-known to those skilled in the art, and many are commercially available. The surfactant may be a silicone surfactant, a non-silicone surfactant, or a combination thereof. Examples of suitable silicone surfactants include, but are not limited to, TEGOSTAB B-8427, B-8454, B- 8404, B-8407, B-8409, B-8715, and B-8462 from Evonik; NIAX L-2171, L-5130, L- 5180, L-5340, L-5440, L-6100, L-6900, L-6980, and L-6988 from MOMENTIVE, and VORASURF DC 5164, from The Dow Chemical Company. Examples of non-silicone surfactants include, but are not limited to, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, turkey red oil, groundnut oil, paraffins, silicone surfactants, and fatty alcohols.

[0036] The surfactant can be from 0.05 to 5 parts by weight, per 100 parts by weight of the formulated polyol composition. All individual values and subranges from 0.05 to 5 parts are included; for example, the surfactant may be from a lower limit of 0.05, 0.08, 0.1, or 0.2 parts to an upper limit of 5, 4, 3, or 2 parts per 100 parts by weight of the formulated polyol composition.

[0037] The formulated polyol composition can include a catalyst. Different catalysts may be utilized for various applications. The catalyst may be a blowing catalyst, a gelling catalyst, a balanced catalyst, or a combination thereof. As used herein, blowing catalysts and gelling catalysts may be differentiated by a tendency to favor either the urea (blow) reaction, in the case of the blowing catalyst, or the urethane (gel) reaction, in the case of the gelling catalyst; a balanced catalyst.

[0038] Examples of blowing catalysts, include, but are not limited to, short chain tertiary amines or tertiary amines containing an oxygen. The amine basedcatalyst may not be sterically hindered. For instance, blowing catalysts include bis- (2-dimethylaminoethyl)ether; pentamethyldiethylene-triamine, triethylamine, tributyl amine, N,N-GLPHWK\ODPLQRSURS\ODPLQH^^GLPHWK\OHWKDQRODPLQH^^1^1^1ƍ^1ƍ-tetra- methylethylenediamine, and combinations thereof, among others. An example of a commercial blowing catalyst is POLYCAT 5, from Evonik, among other commercially available blowing catalysts.

[0039] Examples of gelling catalysts include, but are not limited to, organometallic compounds, cyclic tertiary amines and / or long chain amines, e.g., that contain several nitrogen atoms, and combinations thereof. Organometallic compounds include organotin compounds, such as tin(II) salts of organic carboxylic acids, e.g., tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate, and dialkyltin(IV) salts of organic carboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate. Bismuth salts of organic carboxylic acids may also be utilized as the gelling catalyst, such as, for example, bismuth octanoate. Cyclic tertiary amines and / or long chain amines include dimethylbenzylamine, triethylenediamine, and combinations thereof., and combinations thereof. Examples of a commercially available gelling catalysts are POLYCAT 8, DABCO EG, and DABCO T-12 from Evonik, among other commercially available gelling catalysts.

[0040] Examples of balanced catalysts, include, but are not limited to, POLYCAT 15, POLYCAT 58, DABCO T, DABCO NE 1065 from Evonik, among other commercially available balanced catalysts.

[0041] The catalyst may be from 0.05 to 10.0 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition. All individual values and subranges from 0.05 to 10.0 parts are included; for example, the catalyst may be from a lower limit of 0.05, 0.07, 0.1, 0.2, or 0.3 parts to an upper limit of 10.0, 9.0, 8.0, 7.0, 6.0, 5.0, 4.5, 4.0, 3.5, 3.4, or 3.3 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

[0042] Embodiments of the present disclosure provide that the formulated polyol composition may include a blowing agent. The blowing agent may be a physical blowing agent, a chemical blowing agent, or combinations thereof.

[0043] Examples of physical blowing agents include liquid carbon dioxide; ketones, such as acetone; esters; aldehydes; alkanes; cycloalkanes, such as, cyclopentane, cyclohexane, cyclobutane and mixtures thereof; other cycloalkanes having up to 7 carbon atoms; ethers, such as dialkyl ethers, cycloalkylene ethers, fluoroalkanes, hydrofluoroolefins, hydrochlorofluoroolefins, and mixtures thereof. Examples of alkanes include, but are not limited to, propane, butane, n-butane,isobutane, n-pentane, isopentane and combinations thereof. Examples of dialkyl ethers include dimethyl ether, methyl ethyl ether, methyl butyl ether, diethyl ether, and combinations thereof. An example of a cycloalkylene ether is furan. Examples of fluoroalkanes include, but are not limited to, pentafluoropropane, trifluoromethane, difluoromethane, difluoroethane, tetrafluoroethane, hepta-fluoropropane, pentafluorobutane, heptafluorobutane, and combinations thereof, among others. Examples of hydrofluoroolefins and / or hydrochlorofluoroolefins include, but are not limited to 1,1,1,4,4,5,5,5-octafluoro-2-pentene (HFC-1438mzz), Z-1,1,1,4,4,4- hexafluoro-2-butene (HFC-1336mzz, Z-isomer), trans-1,3,3,3-tetrafluoropropene, 1- chloro-3,3,3-trifluoropropene (HFO-1233zd). An example of a commercially available physical blowing agents is Solstice 1233zd Liquid Blowing Agent from Honeywell, among other commercially available physical blowing agents.

[0044] Examples of chemical blowing agents include, but are not limited to, water, formic acid, CO2 generating materials, and combinations thereof.

[0045] The blowing agent may be from 1 to 15 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition. All individual values and subranges from 1 to 15 parts are included; for example, the blowing agent may be from a lower limit of 1.0, 1.5, or 2.0 parts to an upper limit of 15, 10, or 8 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

[0046] The formulated polyol composition can include a crosslinker. As used herein, the term "crosslinker" includes both compounds generally known as crosslinkers and compounds generally known as chain extenders or more simply extenders. Crosslinkers are compounds that contain two or more isocyanate- reactive groups, such as hydroxyl groups, primary amines, or secondary amines. Examples of crosslinkers include, but are not limited to, amines, including polyamines; polyhydric alcohols; polyoxyalkylene polyols; polyhydric aromatic compounds, and combinations thereof. Examples of amines include, but are not limited to, diethanolamine, triethanolamine, triisopropanolamine, diisopropanolamine, t-butyltolylenediamine, triaminonane, diethyltolylenediamine, chlorodiaminobenzene, 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline), and combinations thereof. Examples of polyhydric alcohols include, but are not limited to, 1,3 butanediol; 1,4 butanedio; mono-, di-, and tri-ethylene glycols; 1,2,4-butanetriol; dipropylene glycol; glycerin; trimethylolpropane; pentaerythritol, 2,5-dimethyl-1,2,6-hexanetriol; glycerol; and combinations thereof.

[0047] The crosslinker may be from 0.01 to 3 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition. Allindividual values and subranges from 0.01 to 3 parts are included; for example, the crosslinker may be from a lower limit of 0.01, 0.05, 0.1, or 0.2 parts to an upper limit of 3, 2, or 1 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

[0048] The crosslinker may have an equivalent weight from 30 to 400. All individual values and subranges from 30 to 400 are included; for example, the crosslinker may have an equivalent weight from a lower limit of 30, 40, 50, 60, 75, 90, or 100 to an upper limit of 400, 350, or 300.

[0049] As mentioned, the foam formulations disclosed herein include a formulated polyol composition and an isocyanate composition. The isocyanate composition can include the biuret oligomers. One or more embodiments provide that the isocyanate composition comprises diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, or a combination thereof, wherein the isocyanate composition includes from 19 to 25 parts of biuret oligomers based upon 100 parts of the isocyanate composition.

[0050] Biuret oligomers can be formed with a starting material, e.g., diphenylmethane diisocyanate (MDI) and / or polymethylene polyphenylisocyanate (PMDI). The starting material is reacted with reactant, such as; water, certain amine FRPSRXQGV^^PRQRVXEVWLWXWHG^XUHDV^VXFK^DV^ȃ^ȃ^-dialkyl urea compounds, formic acid, and / or tertiary alcohol compounds. For instance, water can react with two polyisocyanate groups to produce a urea structure; further reaction of this urea structure with a third polyisocyanate molecule produces a biuret group. The biuret group corresponds to structure (I)

[0051] in which each of the nitrogen atoms is bonded to the residue (after removal of an isocyanate group) of a molecule of the starting polyisocyanate. The biuret oligomer contains at least one biuret group as shown in structure (I), and contains at least three isocyanate groups. Thus, for example, a biuret oligomer molecules formed from three molecules of 4,4'-MDI and one molecule of water has the structure (II).

[0052] Analogous structures form when biuret oligomer molecules are formed using 2,4'- MDI, a mixture of 2,4'- and 4,4'-MDI, or a PMDI product as the starting material. One or more of the remaining isocyanate groups on a biuret oligomer molecules such as that shown in structure II can react with additional water and more of the isocyanate-containing molecules to produce higher molecular weight oligomers containing multiple biuret linkages. This reaction is believed to proceed step-wise, with an intermediate urea group being formed first, which is then converted to an additional biuret linkage. Thus, for example, the structure II material can react with a molecule of water and an additional molecule of 4,4'-MDI to form a biuret urea having the structure III

[0053] which then reacts with another isocyanate molecule to produce a bis- biuret oligomer molecule such as that having the structure IV:

[0054] Structures analogous to those shown in structures (III) and (IV) are produced when the isocyanate is 2,4'-MDI, a mixture of 2,4'-MDI and 4,4'-MDI, or a PMDI product. Either of the urea nitrogens shown in structure III can react with an isocyanate group to form the second biuret linkage.

[0055] A bis-biuret oligomer molecule such as that exemplified by structure (IV) can of course undergo further reactions with water and additional isocyanate compounds to form even higher molecular weight molecules that have three or more biuret groups. As before, these reactions each proceed through a urea group- containing intermediate, analogous to that exemplified in structure (III). The number of isocyanate groups contained by the biuret oligomer molecule will increase with the number of biuret linkages. The number of isocyanate groups on a biuret oligomer molecule is generally equal to two plus the number of biuret linkages.

[0056] An isocyanate component containing biuret oligomers can be produced by reacting 2,4'-MDI, 4,4'-MDI, a mixture of 2,4'- and 4,4'-MDI, or a polymethylene polyphenylisocyanate, with water. From about 0.5 to about 3 parts by weight water per 100 parts by weight of the starting polyisocyanate(s) can be utilized. The isocyanate can be heated to about 80 to 120 °C before mixing it with the water. The water can be added gradually to the isocyanate to help control the reaction. Urea groups tend to form rapidly, but the reaction of the urea groups with additional isocyanate groups to form the biuret linkages tends to proceed more slowly. Thereaction mixture may be ‘cooked down’ after the water has been added, at a temperature of from 110 to 150 °C, to convert the urea groups to biuret linkages. The reaction can be continued until the content of urea-containing molecules in the reaction mixture is reduced to no greater than 5% by weight, or for some applications to no greater than 2% by weight.

[0057] The reaction product can be diluted with more MDI or PMDI to produce the final product. Thus, for example, water and polyisocyanate can be reacted to form an intermediate which contains from 50 to 80% by weight of biuret oligomers. The intermediate can be diluted with additional MDI or PMDI to reduce the biuret oligomer concentration and / or the viscosity to desirable levels. It may be desirable to perform the water / isocyanate reaction on 2,4'-MDI, 4,4'-MDI or a mixture thereof, and to perform the dilution step with a PMDI. However, it is possible to use the same polyisocyanate in both steps, or to perform the biuret-forming reaction on a PMDI and dilute the intermediate with 2,4'- and / or 4,4'-MDI.

[0058] The isocyanate composition includes the isocyanate component including biuret oligomers, e.g., the reaction product of 2,4'-MDI, 4,4'-MDI, a mixture of 2,4'- and 4,4'-MDI, and / or a polymethylene polyphenylisocyanate with water. The isocyanate component including biuret oligomers may be from 45 to 70 parts of the isocyanate composition based upon 100 parts of the isocyanate composition. All individual values and subranges from 45 to 70 parts are included; for example, the isocyanate component including biuret oligomers may be from a lower limit of 45, 50, or 55 parts to an upper limit of 70, 65, or 62 parts of the isocyanate composition based upon 100 parts of the isocyanate composition.

[0059] The isocyanate component including biuret moligomers can include various amounts of biuret oligomers. The isocyanate component including biuret oligomers can include from 35 wt% to 45 w% biuret oligomers based upon 100 wt% of the isocyanate component including biuret oligomers. All individual values and subranges from 35 wt% to 45 w% are included; for example, the biuret oligomers may be from a lower limit of 35, or 36 wt% to an upper limit of 45, 44, or 43 wt% of the isocyanate component including biuret oligomers based upon 100 wt% of the isocyanate component including biuret oligomers.

[0060] The isocyanate composition, e.g., via the isocyanate component including biuret oligomers, can include the biuret oligomers. The biuret oligomers may be from 19 to 25 parts of the isocyanate composition based upon 100 parts of the isocyanate composition. All individual values and subranges from 19 to 25parts are included; for example, the biuret oligomers may be from a lower limit of 19, 19.5,or 19.8 parts to an upper limit of 25, 23, or 22 parts of the isocyanate composition based upon 100 parts of the isocyanate composition.

[0061] One or more embodiments provide that the product isocyanate component including oligomers, e.g., the reaction mixture, can have, in addition to a biuret oligomer content as described before, (1 ) no more than 5% by weight and preferably no more than 2% by weight of urea-group containing oligomers (including biuret-urea oligomers) and (2) an isocyanate content of from 20 to 30% (isocyanate equivalent weight of from 140 to 210), preferably from 23 to 28% (isocyanate equivalent weight of from 150 to 185). A biuret-modified polyisocyanate can be prepared from a mixture of 2,4'- and 4,4'-MDI and / or a PMDI product which contains both 2,4'- and 4,4'-MDI in addition to polymethylene polyphenylisocyanate compounds.

[0062] It is also possible to introduce urethane groups into the isocyanate component including biuret oligomers through reaction with one or more polyol compounds. This can be done (1 ) on the biuret-modified polyisocyanate, (2) on any of the starting polyisocyanate compounds before they are reacted to introduce biuret groups or (3) on a polyisocyanate compound that is used to dilute a biuret-modified polyisocyanate. The polyol used to introduce urethane groups can have a hydroxyl equivalent weight of about 30 to 2000. The isocyanate content of the resulting material can be from 20 to 30%, or from 23 to 28%.

[0063] The isocyanate composition can include an isocyanate, e.g., in addition to the isocyanate component including biuret oligomers. The isocyanate can be 2,4'- MDI, 4,4'-MDI, PMDI, or combinations thereof. The isocyanate can be made by a known process. The isocyanate can be obtained commercially. Examples of commercial 2,4'- MDI and 4,4'-MDI compositions include ISONATE OP 50 and ISONATE OP 30, from The Dow Chemical Company. An example of a commercial PMDI composition is VORANATE M-220, from The Dow Chemical Company.

[0064] The isocyanate may be from 30 to 55 parts of the isocyanate composition based upon 100 parts of the isocyanate composition. All individual values and subranges from 30 to 55 parts are included; for example, the isocyante may be from a lower limit of 30, 35, or 38 parts to an upper limit of 55, 50, or45 parts of the isocyanate composition based upon 100 parts of the isocyanate composition.

[0065] One or more embodiments provide that the isocyanate composition includes from 20 to 45 parts of 2,4'- MDI, 4,4'-MDI, or combinations thereof based upon 100 parts of the isocyanate composition. All individual values and subranges from 20 to 45 parts are included; for example, the 2,4'- MDI, 4,4'-MDI, or combinations thereof may be from a lower limit of 20, 22, or 25 parts to an upper limitof 45, 43, or 40 parts of the isocyanate composition based upon 100 parts of the isocyanate composition.

[0066] One or more embodiments provide that the isocyanate composition includes from 5 to 15 parts of PMDI based upon 100 parts of the isocyanate composition. All individual values and subranges from 5 to 15 parts are included; for example, the PMDI may be from a lower limit of 5, 7, or 8 parts to an upper limit of 15, 12, or 10 parts of the isocyanate composition based upon 100 parts of the isocyanate composition.

[0067] The foam formulations disclosed herein may have an isocyanate index from 60 to 110. All individual values and subranges from 60 to 110 are included; for example, the foam formulations may have an isocyanate index from a lower limit of 60, 65, 70, 75, or 70 to an upper limit of 110, 105, or 100. Isocyanate index may be determined as [isocyanate groups / active hydrogen groups × 100].

[0068] The foam formulations disclosed herein may include one or more additional known components, such as diluents, rheological modifiers, or pigments, among others. Various amounts of the one or more additional known components may be utilized for various applications.

[0069] The foam formulations disclosed herein may be cured, e.g., the formulated polyol composition and the isocyanate composition may be combined, to form a cured product. The cured product may be a foam. The formulated polyol composition and the isocyanate composition may be combined using known methods, equipment, and conditions, which may vary for different applications.

[0070] Advantageously, foams made with the foam formulations disclosed herein have a compression set at 50% not greater than 14%. For example, the foam may have a compression set at 50% from 3% to 14%. All individual values and subranges from 3% to 14% are included; for example, the foam may have a compression set at 50% from a lower limit of 3%, 4%, or 5% to an upper limit of 14% 12%, or 10%. Compression set at 50% can be determined according to ASTM D3574.

[0071] Foams made with the foam formulations disclosed herein may have a density from 35 to 65 kg / m3. All individual values and subranges from 35 to 65 kg / m3are included; for example, the foam may have a density from a lower limit of 35, 40, or 45 kg / m3to an upper limit of 65 ,60, or 55 kg / m3. Density can be determined according to ASTM D1622.

[0072] Foams can be prepared by combining components discussed herein to form a foam-forming reaction mixture. One or more embodiments provide that surfactant(s), catalyst(s), blowing agent(s) and various polyols all can be mixedtogether before they are combined with the isocyanate, e.g., the non-biuret modified isocyanate, and / or the biuret modified isocyanate composition. Alternatively, they can be combined with the isocyanate individually, e.g., as separate streams, or can be formed into any sub-mixtures that are then combined with the isocyanate. The components can be mixed at a temperature from 5 to 80 °C, for example. The components may be mixed together using equipment such as a spray apparatus, a low pressure impingent mixer, a high pressure impingent mixer, a static mixer, a liquid dispensing gun or a mixing head, or a stirred vessel, for instance.

[0073] The reaction mixture reacts to form a foam. The process of this disclosure requires no special processing conditions; therefore, general processing conditions and equipment described in the art for foams are suitable. In general, the components of the reaction mixture are combined and the mixed foam-forming reactive composition is subjected to conditions sufficient to allow the foaming reaction to occur.

[0074] Foams of the present disclosure are useful in various applications, such as cushions, seating, pads, coverings and panels, such as for automotive or mass transit uses, among other applications.

[0075] The following examples are provided for illustration but are not intended to limit the scope. All parts and percentages are by weight unless otherwise indicated. EXAMPLES

[0076] In the Examples, various terms and designations for materials are used including, for instance, the following.

[0077] Alkali metal carboxylate (DABCO K2097; solution of potassium acetate (30%) in diethylene glycol; obtained from Evonik).

[0078] Polyol 1 (non-amine polyol, glycerine initiated ethylene oxide endcapped polyether polyol; functionality 3; HEW 2000; approximately 20 wt% EO); Polyol 2 (non-amine polyol, sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol;functionality 4.7; HEW 1726; approximately 20 wt% EO); Polyol 3 (non-amine polyol, high EO polyol, EO / PO mixed feed glycerine initiated polyether polyol; functionality 3; HEW 1675; approximately 75 wt% EO;).

[0079] Amine containing alcohol (amine-initiated [bis (3- aminopropyl)methylamine-initiated] autocatalytic polyoxyethylene-capped polyoxypropylene polyol; HEW 1700; functionality of 4, a polyoxyethylene capped percentage approximately 17.5%; hydroxyl number of approximately 3).

[0080] Isocyanate 1 (ISONATE OP 50, MDI, 50% 4-4'-diphenylmethane diisocyanate and 50% 2,4'-diphenylmethane diisocyanate, from The Dow ChemicalCompany); Isocyanate 2 (ISONATE OP 30, MDI, 30% 4-4'-diphenylmethane diisocyanate and 70% 2,4'-diphenylmethane diisocyanate, from The Dow Chemical Company); Isocyanate 3 (VORANATE M-220, polymeric MDI, from The Dow Chemical Company).

[0081] An isocyanate component including biuret oligomers was made as follows. Isocyanate 1 (98.9 parts by weight) was charged to a stainless steel container equipped with a recycle line including an in-line static mixer, an internal heater, and a variable speed stirrer. The contents of the container were heated to 105 °C with stirring and recycling through the recycle line. Under nitrogen, water (1.1 parts by weight) was added to the contents of the container over approximately 1.5 hours by injection into the recycle line while stirring and maintaining the contents of the container at 105 °C. CO2 was generated as a reaction between water and isocyanate proceeded; when the water addition was completed, the contents of the container were heated to 120 °C and maintained with continued stirring, for another two hours to provide the biuret modified isocyanate composition that included the biuret oligomers. The product had an NCO content = 26% by weight and contained 36% by weight of biuret oligomers.

[0082] POLYCAT 15 (catalyst; bis(N,N-dimethyl-3-amino-propyl)amine; obtained from obtained from Evonik); DABCO NE 1070 (catalyst; 3- (dimethylamino)propyl urea; obtained from obtained from Evonik).

[0083] Diethanolamine (crosslinker; obtained from The Dow Chemical Company).

[0084] TEGOSTAB B 8715 (surfactant; obtained from Evonik).

[0085] Example 1, a foam formulation, was made by combining the formulated polyol composition and the isocyanate composition, as shown in Table 1, utilizing a Cannon A40 machine (Cannon USA) equipped with a FPL mixing head (injection pressures were 160 bar, injection temperatures were 25 °C, and output was 25 g / s); foam was formed from Example 1 utilizing an aluminum mold that was treated with a release agent and heated to 50 °C by recirculating water. A demolding time of 5 minutes was utilized, after which a mechanical roll crusher was utilized to open internal cells. The foam was fire tested according to the UNI 9175 C.S.E. RF4 test. Compression set at 50% was determined according to ASTM D3574. Foam density was determined according to ASTM D1622.

[0086] Examples 2-8 and Comparative Examples A-D were made as Example 1, with changes shown in Tables 1-3. Table 1Table 2Table 3

[0087] The data of Tables 1 and 2 illustrate that each foam respectively made from Examples 1-8 passed fire test UNI 9175 C.S.E. RF4 and provide a Class 1 IM rating. Further, each foam respectively made from Examples 1-8 also had a compression set at 50% no greater than 14%.

[0088] The data of Table 3 illustrate that, in contrast to each foam respectively made from Examples 1-8, each foam made from Comparative Examples A-D fails to pass fire test UNI 9175 C.S.E. RF4 and provide a Class 1 IM rating, while simultaneously providing a compression set at 50% no greater than 14%.

Claims

What is claimed is:

1. A foam formulation comprising: a formulated polyol polyether composition comprising: a non-amine containing polyol, wherein the non-amine containing polyether polyol is from 70 to 90 parts by weight, per 100 parts by weight of the formulated polyol composition; an alkali metal carboxylate, wherein the alkali metal carboxylate is from 0.01 to 0.1 parts by weight, per 100 parts by weight of the formulated polyol composition; and an amine containing alcohol, wherein the amine containing alcohol is from 10 to 30 parts by weight, per 100 parts by weight of the formulated polyol composition; and an isocyanate composition comprising diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, or a combination thereof, wherein the isocyanate composition includes from 19 to 25 parts of biuret oligomers based upon 100 parts of the isocyanate composition.

2. The foam formulation of claim 1, wherein the alkali metal carboxylate includes from 2 to 12 carbon atoms and lithium, sodium, or potassium.

3. The foam formulation of claim 1 or 2, wherein the amine containing alcohol has a hydroxyl functionality of from 1 to 8 and a hydrogen equivalent weight (HEW) from 250 to 3500.

4. The foam formulation of any one of the preceding claims, wherein the formulated polyol composition has an isocyanate index from 60 to 110.

5. The foam formulation of any one of the preceding claims, wherein the non- amine containing polyether polyol comprises a glycerine initiated ethylene oxide endcapped polyether polyol, a sorbitol and glycerine initiated ethylene oxide endcapped polyether polyol, a high ethylene oxide polyol, or a combination thereof.

6. The foam formulation of any one of the preceding claims, wherein the formulated polyol composition includes a blowing agent that is 1 to 15 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

7. The foam formulation of claim 6, wherein the blowing agent is water.

8. The foam formulation of any one of the preceding claims, wherein the formulated polyol composition includes a surfactant that is from 0.05 to 5 parts by weight, per 100 parts by weight of the formulated polyol composition.

9. The foam formulation of any one of the preceding claims, wherein the formulated polyol composition includes a catalyst that is from 0.05 to 10.0 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

10. The foam formulation of any one of the preceding claims, wherein the formulated polyol composition includes a crosslinker that is from 0.01 to 3 parts of the formulated polyol composition based upon 100 parts of the formulated polyol composition.

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