Reactive flame retardants for flexible polyurethane foams

Abstract

The invention provides dialkyl phosphorus-containing compounds, namely reactive monohydroxy-functional dialkyl phosphinates, that act as very efficient reactive flame retardants in flexible polyurethane foams. The invention further provides fire-retardant polyurethane compositions comprising the reaction product of the monohydroxy-functional dialkyl phosphinates with polyols and isocyanate foam-forming components.

Description

[0001] This application is a divisional application of Chinese invention application (Invention title: Reactive flame retardant for flexible polyurethane foam, application date: July 23, 2018; application number: 201880049392.7).

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 536,260, filed July 24, 2017, which is incorporated herein by reference. Technical Field

[0004] This disclosure provides the use of reactive dialkyl phosphorus compounds, namely hydroxyl-functionalized dialkylphosphine esters, which, upon reaction with polyols and isocyanates, act as highly effective reactive flame retardants in flexible polyurethane foams (foams). The invention further provides fire-retardant flexible polyurethane foams in which the hydroxyl-functionalized dialkylphosphine esters are reacted and incorporated into the polymer matrix of the flexible polyurethane foam. The terms "fire retardant" and "flame retardant" are used interchangeably herein. Background Technology

[0005] It is known that brominated or phosphorus-based flame retardants are highly effective and, in many cases, the only option for reducing the ignition (fire) risk of synthetic materials such as flexible polyurethane foam. However, increased public and governmental oversight of chemicals (and particularly flame retardants) has been intensifying in recent years. The aim is to move towards more sustainable, reactive, polymeric, and / or halogen-free new products. Oversight would be significantly reduced if the flame retardant reacts into the polymer matrix and cannot leach out.

[0006] Therefore, there is a demand for reactive phosphorus-containing fire retardants for flexible polyurethanes that possess characteristics such as high phosphorus content, transparent light color, and good compatibility with polyether polyols and polyester polyols used in the polyurethane industry. Summary of the Invention

[0007] This invention provides reactive dialkyl phosphorus-containing monohydroxy functionalized compounds that possess highly satisfactory flame-retardant properties and good compatibility with the polyol components of flexible polyurethane foam forming systems. As used herein, "flexible polyurethane foam forming system" is understood to include polyols, isocyanates, and reactive dialkyl phosphorus-containing monohydroxy functionalized compounds as described herein. These monohydroxy functionalized dialkylphosphinate compounds are sufficiently reactive through their single hydroxyl functional group and are easier to formulate compared to di- or tri-hydroxy functionalized dialkylphosphinate compounds. Surprisingly, it has been found that, despite the lower content of hydroxyl functional groups in the reactive monohydroxy functionalized dialkylphosphinate compounds described herein, they can be reacted, for example, with the isocyanate components of the flexible polyurethane foam forming system and incorporated into the polymer structure of the flexible polyurethane foam without compromising its elastic properties. This means that the flame retardants of this invention become integrated into the flexible foam matrix, preventing their release into the environment and making them unlikely to penetrate the cell membranes of living tissues, thus posing no health hazard. The present invention further provides the above-mentioned flexible polyurethane foam forming system, including but not limited to the reactive dialkyl phosphorus-containing monohydroxy functional compounds described herein.

[0008] As used herein, the term "foam" refers to flexible polyurethane foam. Flexible polyurethane foam described herein or claimed herein to comprise, substantially comprise, or comprise of, a group of reacted monohydroxy functional dialkylphosphinate compounds of general formula (IA) and / or (IB) (general formula (IB) represents the group of products of a reaction of a polyol (polyol) with a phosphorylation of a partially phosphorylated (phosphorylated) phosphorylation group containing at least one phosphorus-containing diol and / or polyol), is understood herein to contain the foregoing formula as a reactive material, i.e., the foregoing formula reacts into the structure of the flexible polyurethane material, in which case the foregoing formula may not exist, or will not exist, in the same structural form as described herein, but will exist in the flexible polyurethane material as a reaction product of a diol and / or polyol, isocyanate, and the structural form described herein.

[0009] The term “polyol” as used in this article will be understood to also be defined as diols and / or polyols.

[0010] This invention provides a group of monohydroxy-functional dialkylphosphinate compounds of general formulas (IA) and (IB), and partially phosphorylated phosphorus-containing diols and / or polyols of general formula (IB) comprising at least one phosphorus-containing group, wherein formula (IA) is:

[0011] (IA)

[0012] in:

[0013] R 1 and R 2 Selected from straight-chain or branched alkyl groups containing 1-4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl, preferably methyl or ethyl, more preferably R. 1 and R 2 Both are ethyl; and

[0014] X is or ,

[0015] And when X is When Z is –(Y–O) n – where Y is a straight-chain or branched alkylene group containing 2-8 carbon atoms, preferably 2-4 carbon atoms, more preferably ethylene, propylene, or isopropylene, and n represents an integer from 1 to 20, preferably 1 to 5, and more preferably 1 to 2.

[0016] k can be 0 or 1;

[0017] R 3 Selected from hydrogen, and linear or branched alkylene compounds with monohydroxyl-terminated ends comprising 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms; and

[0018] The condition is that when k is 0, R 3 R is a monohydroxy-terminated straight-chain or branched alkylene group, and when k is 1. 3 It is hydrogen, and

[0019] When X is At that time, R 4 and R 5 Each is independently selected from H, a straight-chain or branched alkyl group comprising 1-8 carbon atoms, preferably 1 to 4 carbon atoms, and most preferably any one of methyl, ethyl, or propyl; a straight-chain or branched alkenyl group comprising 2-8 carbon atoms, preferably 2 to 4 carbon atoms; a halogen-substituted alkyl group comprising 1-8 carbon atoms; an alkoxy group comprising 1-8 carbon atoms, preferably 1 to 4 carbon atoms; an aryl group comprising 6-12 carbon atoms, preferably 6 to 8 carbon atoms; and an alkylaryl group comprising 7-16 carbon atoms, preferably 7 to 12 carbon atoms, or R. 4 and R 5 They bond to each other to form cycloalkyl groups comprising 4 to 8 carbon atoms, preferably 6 carbon atoms; and wherein the formula (IB) is:

[0020] (IB)

[0021] in:

[0022] R 1 and R 2 Independently selected from straight-chain or branched alkyl groups containing 1-4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl, preferably methyl or ethyl, more preferably R. 1 and R 2 Both are ethyl; and

[0023] n 1 n is an integer equal to or greater than 1, and n 2 If the value is 1, then n is preferred. 1 From 1 to approximately 5, and

[0024] Z 2 For compounds derived from diols or polyols with a oxidation state of n 1 +n 2 The part is defined by the following general formula:

[0025]

[0026] Where R is selected from:

[0027] or

[0028]

[0029] And each of the R's 6 Independently, it is an H or an alkyl group with 1-4 carbon atoms, x is 0 or ≥1, preferably 1-4, more preferably x=1, y is 2 or 3; z is an integer from 2 to 5; and m ≥ 1, preferably m=1.

[0030] This article also provides the process for preparing these compounds.

[0031] The new compound of formula (IA) can be prepared by reacting a monohydroxy functional dialkylphosphine acid of formula (II) with a compound having an oxacyclopropane group, wherein formula (II) is:

[0032] (II)

[0033] Where R 1 and R 2 As defined.

[0034] Compound (IA) can also be prepared by reacting a dialkylphosphine halide of formula (III) with an aliphatic diol, wherein formula (III) is:

[0035] (III)

[0036] And R among them 1 and R 2As defined, and A is chlorine or bromine.

[0037] The phosphorus-containing diols and / or polyols of the present invention, such as those of formula IB, can be prepared by reacting dialkylphosphino halides of formula (III) with aliphatic diols and / or polyols.

[0038] The reactive monohydroxy functional dialkylphosphonates of the present invention have high phosphorus content, good hydrolytic and thermal stability, good compatibility with diol and / or polyol components in flexible polyurethane foam forming systems, and can be used as highly efficient reactive flame retardants in flexible polyurethane foams.

[0039] The present invention further provides a fire-retardant flexible polyurethane comprising reactive residues (residues) after the phosphorus-containing monohydroxy functionalized compound has reacted in a flexible polyurethane foam forming system to form a flexible polyurethane foam. The phosphorus-containing monohydroxy functionalized compound herein may be used alone or in mixtures with each other and / or with other flame retardants (including halogenated and phosphorus-containing flame retardants) in a flexible polyurethane foam forming system.

[0040] All the above and other features and advantages of the present invention will be better understood from the following illustrative and non-limiting detailed description of its preferred embodiments. Detailed Implementation

[0041] In one embodiment, the monohydroxy-functional dialkylphosphinate of formula (IA) can be those of more specific formulas (IA-1) or (IA-2), wherein formula (IA-1) is:

[0042] (IA-1)

[0043] Where R 1 and R 2 Z, k and R 3 As defined above; and

[0044] Equation (IA-2) is:

[0045] (IA-2)

[0046] And R among them 1 R 2 R 4 and R 5 As defined above.

[0047] In one embodiment of this document, the monohydroxy-functional dialkylphosphinate of formula (IA) of the present invention is prepared by reacting a dialkylphosphine acid of formula (II) with a compound of formula (IV) having an oxacyclopropane group, wherein formula (IV) is:

[0048]

[0049] Formula (IV)

[0050] in:

[0051] R 4 and R 5 As defined above.

[0052] In another embodiment of this article, the monohydroxy-functional dialkylphosphinate of formula (IA) of the present invention is prepared by reacting a dialkylphosphinoyl halide of formula (III) with an aliphatic diol of formula (V):

[0053] (V)

[0054] Among them, Z and R 3 The subscript k is as specified above.

[0055] The phosphorus-containing diols and / or polyols of the present invention, such as those of formula IB, are prepared by reaction of a dialkylphosphinohydride of formula (III) with an aliphatic diol or polyol.

[0056] The dialkylphosphonic acid (II) and dialkylphosphonic halogen (III) used as starting materials in the process of this invention are mostly well known in the art. Compounds of formula (II) can be obtained, for example, by hydrolysis of the corresponding dialkylphosphonic halogen (III). The latter can be prepared, for example, by the method described in U.S. Patent No. 3,104,259 (the contents of which are incorporated herein by reference).

[0057] The specific oxacyclopropane compound used in the process for preparing the compounds of formula (IA) or more specifically (IA-1) or (IA-2) of the present invention is selected from, but not limited to, ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxy-5-hexene, 1,2-epoxy-2-methylpropane, 1,2-epoxyoctane, glycidyl methyl ether, glycidyl isopropyl ether, glycidyl isobutyl ether, glycidyl heptayl ether, glycidyl 2-ethylhexyl ether, glycidyl allyl ether, trimethylolpropane triglycidyl ether, styrene oxide, cyclohexene oxide, epichlorohydrin, and combinations thereof. More preferably, ethylene oxide, propylene oxide, and 1,2-epoxybutane are used as the oxacyclopropane compound.

[0058] The specific aliphatic diols used in the process for preparing compounds of formula (IA) or more specifically (IA-1) or (IA-2) of the present invention are selected from, but not limited to, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,4-butanediol, 2-buten-1,4-diol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and other diols having a molecular weight of up to 700.

[0059] The aliphatic diols and / or polyols used in the process for preparing the phosphorus-containing polyols of the present invention can generally be any suitable diols and / or polyols having at least two or at least three reactive hydrogen atoms, examples being those having a functionality of 2 or 3-6, preferably 2, 3 and 4, and preferably a molecular weight of about 100 to about 700. Specific aliphatic diols and / or polyols can be selected from non-polymeric polyols, such as trimethylolpropane, trimethylolethane, or glycerol.

[0060] Preferably, the diols and / or polyols used according to the present invention are polyether diols and / or polyols. These diols and / or polyols are obtained by ring-opening addition reactions of one or more epoxides (e.g., ethylene oxide and propylene oxide) and suitable reactants containing one or more active hydrogen atoms (e.g., alcohols, amines, and acids); more specifically, the reactants may be selected from diols, triols, phenolic varnish resins, pentaerythritol, sorbitol, sucrose, diethylenetriamine, etc. Polyester polyols may also be used according to the present invention; these polyols are obtained by condensation reactions of carboxylic acids, dicarboxylic acids (or polycarboxylic acids) such as adipic acid, phthalic acid, etc., and diols or triols. The aliphatic diols and / or polyols used in the processes for preparing the phosphorus-containing monohydric alcohols, diols, or polyols of the present invention are selected from polymeric diols and / or polyols, such as polyether polyols, polyester polyols, and mixtures thereof.

[0061] In a preferred embodiment of the invention, the reaction of dialkylphosphonic acid (II) and oxacyclopropane compounds takes place in an excess of oxacyclopropane medium in the presence or absence of organic solvents such as tetrahydrofuran, 1,4-dioxane, etc. This is carried out in the case of alkyl or toluene.

[0062] The amount of oxopropane compound used in the reaction with monohydroxydialkylphosphonic acid (II) is 5-300% molar excess relative to monohydroxydialkylphosphonic acid (II), and preferably 50-100% molar excess. Using oxopropane compound in greater than 100% molar excess relative to monohydroxydialkylphosphonic acid (II) is undesirable because it requires the recovery of large amounts of oxopropane.

[0063] Depending on the amount of dialkylphosphonic acid and oxacyclopropane consumed in the reaction, the monohydroxy functional dialkylphosphonates of formula (IA) or more specifically (IA-1) or (IA-2) of the present invention have a phosphorus content of about 8-18% by weight and a hydroxyl value of about 150-315 mg KOH / g.

[0064] For the preparation of a monohydroxy functional dialkylphosphonate (IA) or more specifically (IA-1) or (IA-2) with the highest possible phosphorus content, it is preferred to react the monohydroxy dialkylphosphonic acid (II) with the highest phosphorus content with ethylene oxide and propylene oxide.

[0065] Therefore, compounds of formula (IA) or more specifically (IA-1) or (IA-2) that possess particularly valuable properties are those in which R 1 and R 2 Each is an ethyl group.

[0066] The reaction is carried out at a temperature between 40°C and 120°C, and preferably between 70°C and 90°C. Below 40°C, the reaction becomes unacceptably slow. On the other hand, applying temperatures above 120°C is undesirable because undesirable decomposition products can form at such temperatures.

[0067] In a preferred embodiment, the reaction of dialkylphosphinohydride (III) and aliphatic diol is carried out in a medium with an excess of diol.

[0068] The amount of diol compound used in the reaction with dialkylphosphinohydride (III) is typically 2-10 moles per mole of dialkylphosphinohydride, and preferably 4-8 moles in molar excess. A relatively large excess of these diols is required to minimize the formation of undesirable non-hydroxyl glycols and bis(dialkylphosphinohydride) esters of the diol. Using a molar excess of more than 10 moles of diol compound per mole of dialkylphosphinohydride is undesirable due to the need to recover large amounts of diol.

[0069] Depending on the amount of dialkylphosphinic halogen and diol consumed for the reaction, the monohydroxy functional dialkylphosphinic esters of formula (IA) or more specifically (IA-1) or (IA-2) of the present invention have a phosphorus content of about 2-18% by weight and a hydroxyl value of about 150-450 mg KOH / g.

[0070] To prepare a monohydroxy functional dialkylphosphonate (IA) with the highest possible phosphorus content, or more specifically (IA-1) or (IA-2), it is preferred to react the dialkylphosphonic halide (III) with the highest phosphorus content with ethylene glycol.

[0071] Therefore, the compounds of formula (IA-1) with particularly valuable properties are as follows: where R 1 and R 2 Each is an ethyl group, k is 1, n is 1, Y is –CH2CH2–, and R 3 It is hydrogen.

[0072] The reaction is carried out at a temperature between 25°C and 120°C, and preferably between 50°C and 90°C. Applying temperatures below 25°C results in low yields. On the other hand, applying temperatures above 120°C is undesirable because undesirable decomposition products can form at such temperatures. Additionally, catalysts such as MgCl2 or ZnCl2 can be used to accelerate the reaction.

[0073] In a preferred embodiment, the reaction of the dialkylphosphinohydride (III) and the aliphatic diol is carried out in the presence of a strong base, such as sodium hydroxide or potassium hydroxide, in a medium containing both an organic solvent and an excess of the aliphatic alcohol. The organic solvent is selected from aromatic compounds. Particularly suitable aromatic solvents are chlorobenzene, o-dichlorobenzene, lye, and especially toluene and xylene. The effective amount of base used in the process is in the range of 1-1.2 mol, and preferably 1-1.05 mol, per mol of the dialkylphosphinohydride (III).

[0074] Sodium or potassium hydroxide can be used in solid form. As much water as possible generated from the reaction between the diol and the base should be removed from the reaction mixture before the addition of the dialkylphosphinohydride (III).

[0075] In a preferred embodiment, the reaction of the dialkylphosphinohalide (III) with the aliphatic diol and / or polyol is carried out by altering the degree of partial phosphorylation of the diol and / or polyol. The phosphorus-containing diol and / or polyol according to the invention comprises at least one phosphorus-containing group. This phosphorus-containing group is a group of formula (III-A).

[0076] (III-A)

[0077] in:

[0078] Where R 1 and R 2 As defined, and where the wavy line represents a bond through an oxygen atom to a diol or polyol.

[0079] The phosphorus-containing diols and / or polyols of the present invention may also contain two or more phosphorus-containing groups of formula (III-A), wherein these phosphorus-containing groups may be the same or different.

[0080] The reaction of dialkylphosphinohydride (III) with aliphatic diols and / or polyols can be carried out in the presence of an organic base selected from, but not limited to, tertiary amines such as triethylamine, pyridine, diisopropylethylamine, and 1-methylimidazole. The amount of base used is equimolar with the dialkylphosphinohydride (III). The base may also be used in excess relative to the dialkylphosphinohydride. The reaction is typically carried out in a medium of an inert organic solvent. Suitable solvents for the phosphorylation are, but not limited to, halogenated hydrocarbons such as dichloromethane, chloroform, or 1,2-dichloroethane. Other suitable solvents are ethers, such as diethyl ether... Alkanes or tetrahydrofurans. Other suitable solvents are hydrocarbons such as hexane or toluene.

[0081] In a preferred embodiment, the reaction of dialkylphosphinohalides (III) with aliphatic diols and / or polyols is carried out in the presence of a strong inorganic base, such as sodium hydroxide or potassium hydroxide, in an organic solvent, such as chlorobenzene, lye, and particularly toluene and xylene.

[0082] The effective amount of base used in the process is in the range of 1-1.2 mol, and preferably 1-1.05 mol, per mol of dialkylphosphinohydride (III). Sodium or potassium hydroxide can be used in solid form. As much water as possible generated from the reaction mixture between the diol and / or polyol and the base should be removed before the addition of the dialkylphosphinohydride (III).

[0083] The amounts of dialkylphosphinohydride (III) and diols and / or polyols can be adjusted to achieve the desired degree of functionalization. Partial phosphorylation of the diols and / or polyols can be achieved by using a dialkylphosphinohydride (III) in a less than stoichiometric amount based on their functionality. In this way, only a portion of the OH groups in the diols and / or polyols react with the dialkylphosphinohydride.

[0084] The phosphorus-containing diols and / or polyols of the present invention (also described herein as partially phosphorylated diols and / or polyols) have a residual average OH- functionality of 1 (after its phosphorylation) and a molecular weight of about 200 to about 1000. Depending on the dialkylphosphinohydride and diol and / or polyol consumed for the reaction and the molar ratio thereto, the phosphorus-containing diols and / or polyols of the present invention have a phosphorus content of about 4-20% by weight and a hydroxyl value of about 20-800 mg KOH / g.

[0085] The phosphorylation of diols and / or polyols is carried out at temperatures between 0°C and 100°C, and preferably between 10°C and 90°C. Applying temperatures below 0°C results in a low reaction rate. On the other hand, applying temperatures above 100°C is undesirable because undesirable decomposition products can form at such temperatures.

[0086] The following examples illustrate specific embodiments of the preparation of certain compounds of the present invention and their use as flame retardants in flexible polyurethane foams.

[0087] The compounds of the present invention can be used as reactive flame retardants. These flame retardants can be used as is (as prepared) or as a mixture with halogenated or non-halogenated products. For flexible polyurethane foams, it is preferred that the halogen-free hydroxyl-functionalized dialkylphosphinates of the present invention be used in pure form or in combination with other halogen-free products.

[0088] The compounds of this invention are highly effective reactive flame retardants when introduced into flexible polyurethane foams. It should be noted that the compounds of this invention can be used within a wide range of isocyanate indices (abbreviated herein as MDI or TDI). The index refers to the percentage ratio of the actual isocyanate used in the formulation to the theoretical stoichiometry of the required isocyanate.

[0089] The flexible polyurethane foam described herein comprises the composition of the invention in a typical effective amount of flame retardant. Typically, the composition of the invention is applied in an amount providing a total phosphorus concentration in the polymer, ranging from 0.3% to 15% by weight, based on the total weight of the polymer (i.e., the flexible polyurethane foam). Preferably, the total phosphorus concentration in the polymer is in the range of 1% to 10% by weight, and more preferably in the range of 1.5% to 5% by weight, based on the total weight of the flexible polyurethane polymer. Most preferably, the amount of the reactive flame retardant used in the invention is at least sufficient to meet the current requirements of the flammability testing method MVSS 302.

[0090] Flexible polyurethane foams, with varying properties regarding their degree of flexibility, can be manufactured by appropriately selecting components and conditions. Therefore, flexible foams typically use water as the primary foaming agent (blowing agent) and are made from polymeric diols or triols with hydroxyl values ​​of 20-80.

[0091] The flexible polyurethane foam of the present invention may contain appropriately selected additives, such as catalysts, surfactants, foam stabilizers, etc.

[0092] The flexible polyurethane foam used herein is made from diols and / or polyols (as described herein) having a molecular weight of 3,000 to about 6,000, such as polyether triols prepared by adding propylene oxide to glycerol. The flexible polyurethane foam used herein is characterized by having a core impact resilience of up to 30% and a glass transition point of -80°C to -60°C. Here, the flexible polyurethane foam preferably has a hard segment content of up to 40% by mass. Conventional flexible polyurethane foams have a bulk density (volume density) of 2.5 lb / cm³ or less and a volumetric density of 10-90 lb / 50 in. 2 The range of foam hardness or IFD (which is measured according to test method ASTM 3574-Test B1).

[0093] The method for preparing the flexible urethane foam of the present invention may include one or more combinations of diol and / or polyol components and / or isocyanate components or catalysts and flame retardant materials of formulas (IA), (IA-1), (IA-2) and (IB) described herein, which are metered and pumped into a common mixing container, and the resulting mixture is then readily movable to polymerization sites for use in molds, sheet operations, etc.

[0094] The reactive flame retardant of the present invention may also be premixed with a diol and / or polyol reactant prior to combination with the isocyanate reactant. Combining such a mixture with a diol and / or polyol reactant after mixing the reactive flame retardant material and the isocyanate is also within the scope of the invention. However, a reaction may occur if the isocyanate and the aforementioned flame retardant material are mixed and allowed to stand at room temperature for a substantial period. In one embodiment, the term "reaction product" as used in the claims and description herein may include reacting the contents of a flexible urethane foam forming system in any of the foregoing methods, and may further include reacting the reactive flame retardant via a prepolymerization technique, such as, for example, reacting excess isocyanate and polyol to form an isocyanate-terminated prepolymer and then further reacting the prepolymer with the reactive flame retardant described herein.

[0095] The flame retardant materials of formulas (IA), (IA-1), (IA-2) and (IB) described in this article can be referred to as isocyanate-reactive (NCO-reactive) materials, that is, they can react with isocyanates through hydroxyl groups.

[0096] The diols and / or polyols used in the manufacture of the flexible polyurethane foams described herein may include any organic polyols (including diols, polyols), and polyether, polyester, and polyesteramide polyols having hydrogen atoms that can react with isocyanates may be used. Typically, these materials have a molecular weight in the range of about 62 to about 5,000 and a hydroxyl content of 2 to about 10 or more hydroxyl groups per molecule and a weight percentage in the range of about 0.5 to about 25%. They typically have a hydroxyl value of about 50 to a maximum of 500 or even 700.

[0097] In polyester polyol-type reactants, the acid value should be less than 10, and generally as close to 0 as possible. These materials are simply referred to as "polyol" reactants. Available diols and / or polyols containing active hydrogen include a large family of adducts obtained when ethylene oxide, propylene oxide, 1,2- and 2,3-epoxybutane, or other epoxides are added to such active hydrogen compounds as diols, glycols, and polyols (represented by ethylene glycol, propylene glycol, glycerol, methyl glucoside, sucrose, sorbitol, glycerol, trimethylolpropane, pentaerythritol), as well as various alkylamines and alkylene diamines, and polyalkylene polyamines. Depending on the intended use of the polyurethane, varying amounts of these epoxides can be added to the aforementioned base diol, polyol, or amine molecules.

[0098] For example, the diols and / or polyols used in the manufacture of flexible foams can be represented precisely by glycerol with sufficient propylene oxide added to it to obtain a final hydroxyl content of about 1.7%. Such a material would have a molecular weight of about 3,000 and a glycerol-propylene oxide molar ratio of about 1 glycerol to 50 propylene oxide.

[0099] The technique of controlling flexibility by selecting the amount of diol and / or polyol molecules and subsequently added epoxides is well known to those skilled in the art.

[0100] Besides diols, which can serve as base polyol molecules for the addition of alkylene oxides and thus generate "polyol" molecules for reaction with isocyanates, starting molecules containing primary and / or secondary amine groups with hydrogen atoms reactive to alkylene oxides can also be used. Again, the amount of alkylene oxide added depends on the intended use of the final polyurethane product. In the flexible polyurethane products described herein, alkylene oxides will be used to produce polyols with a low hydroxyl content, for example, from about 0.1% to about 5% or 10%.

[0101] Representative amines that can act as molecules containing active hydrogen to react with epoxides are those having 1 to about 6 or more amino nitrogen atoms, examples of which are ethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetrapropylenepentamine and other linear saturated aliphatic alkyleneamines. An important requirement (prerequisite) is that at least two, and preferably more (e.g., 3-8 or 10) epoxides can be added to their active hydrogen sites.

[0102] It is also well known to use hydroxyl-containing molecules prepared by esterification-type reactions of polyfunctional acids or anhydrides and polyfunctional alcohols as active hydrogen compounds in the preparation of polyurethane systems. These compounds are commonly referred to as polyester polyols. Typical acids used in the manufacture of these polyester polyols are maleic acid, phthalic acid, succinic acid, fumaric acid, tetrahydrophthalic acid, chlorobenzene, and tetrachlorophthalic acid. Typical diols and / or polyols are ethylene glycol, propylene glycol, butanediol, diethylene glycol and dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerol, trimethylolpropane, hexanediol, pentaerythritol, sorbitol, etc. Where available, it is desirable to use the above acids in the form of anhydrides.

[0103] In the manufacture of polyester polyols, any one of a variety of multifunctional acids or anhydrides or mixtures thereof and any one of diols, glycols, or polyols or mixtures thereof are reacted with an excess of hydroxyl groups in a stoichiometric manner, such that the final polyol product comprises primarily hydroxyl-terminated groups. The degree and percentage of hydroxyl functional groups can be readily modified using techniques and skills known to those skilled in the art to provide a desired polyol.

[0104] In the field and technology of manufacturing flexible polyurethane, the use of so-called prepolymer technology is also known. This is a technique in which a portion of the reactions involved in the manufacture of flexible polyurethane is carried out to produce a prepolymer with increased molecular weight, and, depending on the stoichiometry used in the manufacture of the prepolymer, the resulting terminal groups are hydroxyl or isocyanate. The final flexible polyurethane product is then prepared by reacting the prepolymer with an isocyanate or a polyol (depending on whether the prepolymer's terminal groups are hydroxyl or isocyanate as mentioned above).

[0105] In summary, the polyurethanes described herein can be manufactured using any of the following: polyesters with free reactive hydrogen and particularly hydroxyl groups, isocyanate-modified polyester prepolymers, polyesteramides, isocyanate-modified polyesteramides, alkylene glycols, isocyanate-modified alkylene glycols, polyoxyalkylene glycols, isocyanate-modified polyoxyalkylene glycols, etc.

[0106] Examples of usable isocyanates include those having two or more isocyanate groups that have been used to date in the manufacture of flexible polyurethane foams. Examples of such isocyanate compounds include aromatic isocyanates, aliphatic isocyanates, and alicyclic isocyanates, as well as mixtures of two or more such isocyanates, and modified isocyanates obtained by modifying such isocyanates. Specific examples of such isocyanates are toluene diisocyanate, diphenylmethane diisocyanate, polymethylene poly(poly)isocyanate (crude MDI), xylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; and modified products of such isocyanates, such as carbodiimide-modified products, biuret-modified products, dimers, and trimers. Prepolymers with terminal isocyanate groups obtained from such isocyanates and compounds containing active hydrogen can also be used.

[0107] In one embodiment, the isocyanate index of the flexible polyurethane foam may range from about 130 to about 80, more preferably from about 120 to about 90, and most preferably from about 115 to about 95.

[0108] As the blowing agent in the flexible polyurethane foam forming composition of the present invention, a known blowing agent used to date in such a composition is appropriately selected according to the desired properties of the foamed product.

[0109] In this invention, a crosslinking agent may also be used if necessary.

[0110] As the crosslinking agent, compounds having at least two functional groups with active hydrogen (e.g., hydroxyl, primary amino, or secondary amino groups) are preferred. However, in cases where a polyol compound is used as the crosslinking agent, the following considerations are taken into account: that is, a polyol compound having a hydroxyl value of at least 50 mg KOH / g and more than four functional groups is considered as the crosslinking agent, and polyols that do not meet this requirement are considered as any one of the polyols in the above-mentioned polyol mixture (polyols (1), (2), or other polyols). Furthermore, two or more crosslinking agents may be used together. As specific examples, one may mention, for instance, polyols such as glucose, sorbitol, or sucrose; polyols having an epoxide added to the polyol; amine compounds such as monoethanolamine, diethanolamine, ethylenediamine, 3,5-diethyl-2,4 (or 2,6)-diaminotoluene (DETDA), 2-chloro-p-phenylenediamine (CPA), 3,5-bis(methylthio)-2,4 (or 2,6)-diaminotoluene, 1-trifluoromethyl-4-chloro-3,5-diaminobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis(3,5-dimethyl-4-aminophenyl)methane, 4,4'-diaminodiphenylmethane, m-xylylenediamine, 1,4-diaminohexane, 1,3-bis(aminomethyl)cyclohexane, or isophoronediamine; and compounds obtained by adding an epoxide to them.

[0111] When the above-mentioned crosslinking agents are used, even in cases where a large amount of foaming agent is used to manufacture flexible foams with low density, the foaming stability will be good, and it will be possible to manufacture such flexible foams. In particular, when high molecular weight diols and / or polyols are used, it is possible to manufacture low-density flexible foams that were previously considered difficult to foam. Furthermore, when the crosslinking agents are used, durability will be improved compared to cases where they are not used. In cases where high molecular weight diols and / or polyols are used, as in this invention, foaming stability can be easily improved, especially when using compounds with relatively high molecular weights, such as at least 4000.

[0112] Water is a typical example of such a blowing agent; other examples include dichloromethane, n-butane, isobutane, n-pentane, isopentane, dimethyl ether, acetone, carbon dioxide, etc. Depending on the desired density and other properties of the polyurethane foam, these and other blowing agents can be used alone or in combination of two or more in a manner known in the art.

[0113] There is no particular limitation on the amount of foaming agent used, but it is generally in the range of 0.1-20 parts by weight relative to 100 parts by weight of the diol and / or polyol component of the foam forming composition. Preferably, the amount of foaming agent will be such that it provides a foam density of 0.8-2.5 psi, and preferably 0.9-2.0 psi.

[0114] The polyurethane foam forming compositions described herein may preferably comprise any of, or combinations thereof, catalysts known to date or used in the manufacture of polyurethane foams. Examples of available catalysts include sodium hydroxide, sodium acetate, tertiary amines, or materials that produce tertiary amines such as trimethylamine, triethylenediamine, N-methylmorpholine, N,N-dimethylcyclohexylamine, and N,N-dimethylaminoethanol. Also applicable are metal compounds such as hydrogen tin alkylcarboxylate, dibutyltin diacetate, dibutyltin dioctanoate, dibutyltin dilaurate, and stannous octanoate; and other compounds intended to promote the trimerization of isocyanates, such as 2,4,6-tris(N,N-dimethylamino-methyl)phenol, 1,3,5-tris(N,N-dimethyl-3-aminopropyl)-S-hexahydrotriazine, potassium octanoate, potassium acetate, and catalysts such as DABCO TMR® and POLYCAT 43®.

[0115] If desired, many other types of catalysts can be used instead of those listed above. The amount of catalyst used can advantageously be in the range of 0.05-5% by weight or greater, based on the total weight of the diols and / or polyols in the foam-forming mixture.

[0116] The isocyanate (NCO) index used in the manufacture of the flexible foam according to the invention is 95-125, and preferably 100-120. It is generally understood that the NCO index of polyurethane foam is about 80-130.

[0117] The density of the flexible polyurethane foam described in this article can be 14-80, preferably 16-55, and most preferably 20-40 kg / m³. 3 Within the range.

[0118] Surfactants (including organic surfactants and silicone-based surfactants) can be added to act as cell stabilizers. Some representative materials are sold under the names SF-1109, L-520, L-521, and DC-193, which are typically polysiloxane-alkylene oxide block copolymers. Organic surfactants comprising ethylene oxide-butylene oxide block copolymers are also included. It is particularly desirable to use a small amount of surfactant to stabilize the foaming reaction mixture until it cures. Other surfactants available herein are polyethylene glycol ethers of long-chain alcohols, tertiary amines or alkanolamine salts of long-chain allyl sulfates, alkyl sulfonates, alkyl aryl sulfonic acids, and combinations thereof. Such surfactants are used in amounts sufficient to stabilize the foaming reaction and resist collapse and the formation of large, non-uniform cells. Typically, a total amount of about 0.2 to about 3% by weight of surfactant based on the overall formulation is sufficient for this purpose. However, including surfactants such as DABCO DC-5598 (available from Air Products and Chemicals, Inc.) in higher amounts may be desirable in some embodiments. Therefore, surfactants may be included in any amount ranging from 0-6% by weight of the diol and / or polyol components in the formulations of this invention.

[0119] Finally, other additives such as fillers and pigments may be included in the polyurethane foam forming formulations described herein. In non-limiting embodiments, these may include barium sulfate, calcium carbonate, graphite, carbon black, titanium dioxide, iron oxide, microspheres, alumina trihydrate, wollastonite, prepared glass fibers (dropped or continuous), polyester fibers, other polymer fibers, combinations thereof, etc. Those skilled in the art will recognize that typical and suitable means and methods for adapting the formulations of the present invention to the manufacture of flexible polyurethane foams, without further instruction, still fall within the scope of the appended claims, but present or benefit from desired properties and / or processing modifications.

[0120] The flexible polyurethane foams described in this article can be used to construct and form a variety of articles, such as furniture, bedding, and car seat cushions, and more specifically for furniture applications, automotive applications, marine applications, bus seat applications, train seat applications, RV seat applications, office furniture and seat applications, aviation applications, tractor applications, bicycle applications, engine rack applications, compressor applications, bedding applications, isolation applications, sporting goods applications, footwear applications, carpet padding applications, packaging applications, textile applications, cushioning and shock absorption applications, HVAC applications, tent applications, life raft applications, luggage applications, and handbag applications.

[0121] Flexible polyurethane foam sheets can be used in furniture such as upholstered furniture, such as padding, backrests and arms; in the automotive industry such as seats and backrests, as well as headrests and cushions for cars and trucks; in public transportation (such as buses and airplanes) seats and any of the seats for tractors, bicycles and motorcycles; as support rings for safety tires; and other automotive interior components; bedding such as mattresses; as sound insulation materials; automotive interior components such as armrests, steering wheels and gearshift levers; shoe soles; and sporting goods.

[0122] Example

[0123] Preparation Example 1

[0124]

[0125] Diethylphosphonic acid (779 g, 6.38 mol) was charged into a 2-liter jacketed Hastelloy reactor equipped with a mechanical stirrer, oil heater, and positive displacement experimental pump and sealed. The reactor was heated to an internal temperature of 45°C. Propylene oxide (743 g, 12.77 mol) was added to the reactor via pump over two hours while maintaining the temperature below 65°C. The internal temperature of the reactor was then raised to 90°C and maintained therefore for 3 hours. Excess propylene oxide was evaporated, and the residue was evaporated using a scraped film evaporator at 125°C. o Distilled under vacuum (300-500 mTorr) at jacket temperature. The target fraction was collected as a clear, colorless liquid. The yield was 90% relative to the starting diethylphosphonic acid. The product was a mixture of two isomers of hydroxyl-functionalized diethylphosphonic acid ester. 31 P NMR (acetic acid-d4, ppm): 66.8–67.7; with an acid value of 0.4 mg KOH / g and a phosphorus content of 15.9%.

[0126] Preparation Example 2

[0127]

[0128] Diethylphosphonic acid (469 g, 3.84 mol) was charged into a 1-liter flask equipped with a heating mantle, mechanical stirrer, reflux condenser, dip tube, J-Chem controller, thermocouple, and alkaline scrubber. The flask was heated to 80°C, and ethylene oxide from a pressurized tank was added to the reactor via the dip tube over five hours. The final molar ratio of ethylene oxide to diethylphosphonic acid was 1.33. The reaction mixture was maintained at 80°C for another three hours. Excess ethylene oxide was further removed by passing nitrogen through the dip tube. Batch distillation of the residue was completed at 150°C and 200 mTorr to obtain a clear liquid (400 g). The product was a 2-hydroxyethyl ester of diethylphosphonic acid. 31 P NMR (CDCl3, ppm): 79; and has an acid value of 0.4 mg KOH / g.

[0129] The application of the novel compounds of the present invention has been demonstrated by their use as flame retardants in standard formulations of flexible polyurethane foam (Application Example 3).

[0130] In addition to new flame retardant compounds, the following components are also used in the preparation of polyurethane foam:

[0131]

[0132] Application Example 3

[0133] Foam samples were prepared by mixing a polyol with a novel FR product from Preparation Example 1. The remaining components of the formulation, comprising water, an amine catalyst, a silicone surfactant, and a tin catalyst (except for the isocyanate), were added to the polyol / FR product mixture and stirred under the following conditions: 2000 rpm for 30 seconds for polyether foam and 1000 rpm for 60 seconds for polyester foam. The isocyanate was added and introduced into the reaction mixture under vigorous stirring, after which the entire reaction mixture was immediately poured into an 8x8x5” (20x20x20 cm) box and allowed to rise fully. For polyether foam, the box was then placed in a fume hood for 24 hours to cure at room temperature; for polyester foam, the box was first placed in an oven at 110 °C and cured for 10 minutes, followed by curing at room temperature for 24 hours. The top and bottom 0.5” of the foam sample, as well as the paper-backed sides of the foam, were removed. The samples were then cut and tested for flammability, including emissions testing according to Federal Motor Vehicle Safety Standard No. 302 (FMVSS 302) and VDA277.

[0134] Tables 1 and 2 present the composition, parameters, and test results of the foam formulation.

[0135] Table 1. Polyether flexible foam formulation system and test results

[0136]

[0137] SE = Self-extinguishing sample, which is ignited but self-extinguishes before entering the time zone.

[0138] Table 2. Polyester flexible foam formulation system and test results

[0139]

[0140] Although the invention has been described with reference to certain embodiments, those skilled in the art will understand that various changes can be made and equivalents can be substituted for elements therein without departing from the scope of the invention. Furthermore, many modifications can be made to make particular scenarios or materials suitable for the teachings of the invention without departing from its essential scope. Therefore, it is intended that the invention is not limited to the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but rather that the invention will cover all embodiments falling within the scope of the appended claims.

Claims

1. Compounds of formula (IA-2): (I-A-2) in: R 1 and R 2 Each is an ethyl group; and R 4 and R 5 Each is independently selected from H and methyl; and The compound is selected from: , and its mixtures.

2. The compound of claim 1, wherein the compound is a mixture thereof: and .

3. A method for preparing the compound of claim 1, wherein the compound is selected from: , and its mixtures; The method involves reacting a compound of formula (II) with a compound of formula (IV): (II) Where R 1 and R 2 Each is an ethyl group; (IV) Where R 4 and R 5 Each is independently selected from H and methyl; and The compound of formula (IV) is propylene oxide.

4. The method of claim 3, wherein the compound of claim 1 is a mixture of the following: and .

5. The compound of claim 1 or 2, which is used as a flame retardant.

6. A flame-retardant composition comprising a compound according to any one of claims 1 or 2.

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