Rigid polyurethane foam comprising a reactive flame retardant

Abstract

The invention provides a flame-retarded rigid polyurethane foam comprising polyol and isocyanate foam-forming components, and as a flame retardant, the reaction product of a dialkyl phosphorus-containing compound (i.e., a reactive monohydroxy-functional dialkyl phosphinate ester) which functions as a highly effective reactive flame retardant in the rigid polyurethane foam.

Description

[0001] This application is a divisional application of Chinese invention application (Invention title: Rigid polyurethane foam containing reactive flame retardant, application date: July 23, 2018; application number: 201880049383.8).

[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, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This disclosure provides the use of reactive dialkyl phosphorus compounds (i.e., hydroxyl-functionalized dialkylphosphine esters) that act as highly effective reactive flame retardants in rigid polyurethane foams (foams) when reacted with polyols and isocyanates. The invention further provides flame-retardant rigid polyurethane foams that react the said hydroxyl-functionalized dialkylphosphine esters and incorporate them into the polymer matrix of the rigid polyurethane foam. The terms "fire retardant" and "flame retardant" are used interchangeably herein. Background Technology

[0005] Brominated or phosphorus-based flame retardants are known to be highly effective and, in many cases, the only option for reducing the fire risk of synthetic materials such as rigid polyurethane foam. However, public and governmental oversight of chemicals (and particularly flame retardants) has been increasing over the years. The goal is towards more sustainable, reactive, polymeric, and / or halogen-free new products. Oversight would be significantly reduced if flame retardants reacted into the polymer matrix and could not leach out.

[0006] Therefore, there is a demand for reactive phosphorus-containing refractories for rigid polyurethanes with the following characteristics: high phosphorus content, clear (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 a rigid polyurethane foam comprising a reactive dialkylphosphine-containing monohydroxyl-functionalized flame retardant, said flame retardant possessing highly satisfactory flame retardant properties and good compatibility with the polyol component of the rigid polyurethane foam forming system. It should be understood that, as used herein, the term "rigid polyurethane foam forming system" includes polyols, isocyanates, and monohydroxyl-functionalized dialkylphosphine ester compounds as described herein. The monohydroxyl-functionalized dialkylphosphine ester compounds are sufficiently reactive through their monohydroxyl functional groups and are easier to formulate than di- or tri-hydroxyl-functionalized dialkylphosphine ester compounds. It has been unexpectedly found that the reactive monohydroxyl-functionalized dialkylphosphine ester compounds described herein, despite their lower hydroxyl functional group content, can react and be incorporated into the polymer structure of the rigid polyurethane foam, for example, by reacting with the isocyanate component of the rigid polyurethane foam forming system, without compromising the properties of the rigid polyurethane foam. This means that the flame retardant of the present invention is integrated into a rigid foam matrix, making it unlikely to be released into the environment and unlikely to penetrate through living tissue cell membranes, thus posing no health hazard. The present invention further provides the above-described rigid polyurethane foam forming system, which includes, but is not limited to, the reactive dialkyl phosphorus-containing monohydroxy functional compounds described herein.

[0008] As used herein, the term "polyurethane" is understood to include both polyurethane and polyisocyanurate materials. Those skilled in the art can distinguish between polyurethane and polyisocyanurate materials, and such distinction will not be discussed herein.

[0009] As used herein, the term "foam" refers to rigid, semi-rigid, and single-component (OCF) polyurethane and polyisocyanurate foams. Rigid polyurethane foams described herein (or claimed herein) that comprise, are substantially composed of, or are composed of monohydroxy-functional dialkylphosphinate compounds of the reacted general formula (IA) and / or (IB) are understood herein to contain the foregoing formula as a reactive material, i.e., the foregoing formula reacts into the structure of the rigid polyurethane material, in which case the foregoing formula may not or will not be present in the same structural formula as described herein, but will be present in the rigid polyurethane material as a reaction product of diols and / or polyols, isocyanates, and the structural formula described herein, wherein the general formula (IB) represents the group of phosphorodiols and / or polyols that are partially phosphorylated (phosphorylated) to contain at least one phosphorus-containing polyol group.

[0010] It will be understood that, as used herein, the term “rigid” includes rigid foams, semi-rigid foams, and one-component foams in the form of polyurethane and polyisocyanurate formulations.

[0011] It will be understood that the term "polyol" as used herein may also be defined as diols and / or polyols.

[0012] As used herein, the term "one-component foam" (OCF) is understood to refer to in-situ polyurethane foam (DIN 18159) that is moisture-curing and contained in a pressurized container, preferably a disposable pressurized container (aerosol can), and may include polyols, isocyanates, and flame retardants or blends thereof as described herein. Polyurethane OCFs can be used in the construction industry for sealing, insulation, and assembly purposes, such as in applications involving sealing joints, roof surfaces, windows, and doors, but are not limited thereto.

[0013] In one embodiment, the OCF may be prepared from an isocyanate prepolymer, which is in turn prepared by reacting a polyol with an organic diisocyanate and / or a polyisocyanate in the presence of a foam stabilizer and a catalyst, and optionally a plasticizer, a flame retardant as described herein, and other additives. The OCF reaction takes place in a pressurized vessel in the presence of liquefied gas. After the prepolymer is formed, the foam can be discharged in a metered amount through a valve. The foam has a creamy consistency and solidifies under the influence of ambient moisture, for example, from the air, in which process it undergoes a volume increase (one-component foam). An activator may also be added from a separate pressurized vessel just before the foam is applied. The activator provides faster non-stick curing of the foam (two-component foam). The activator may be a short-chain diol, such as ethylene glycol, propylene glycol, butane-1,4-diol, or glycerol.

[0014] The flame retardant blends of the present invention provide a flame-retardant effective amount of a monohydroxy-functional dialkylphosphinate compound of general formula (IA) and (IB), and a reaction product of a polyol-containing diol and / or polyol of general formula (IB) comprising at least one phosphorus-containing group, wherein formula (IA) is:

[0015] (IA)

[0016] in:

[0017] R 1 and R 2 Selected from linear or branched alkyl groups containing 1 to 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,

[0018] X is or ,and

[0019] When X is When Z is –(Y–O) n – where Y is a linear or branched alkylene group containing 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms, more preferably ethylene, propylene, or isopropylene, and n represents an integer from 1 to 20, preferably 1 to 5, and even more preferably 1 to 2.

[0020] k can be 0 or 1;

[0021] R 3 Selected from hydrogen, linear or branched alkylene groups with monohydroxyl-terminated ends comprising 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms; and,

[0022] The premise is that when k is zero, R 3 R is a linear or branched alkylene group capped with a single hydroxyl group, and when k is 1, R 3 For hydrogen, and

[0023] When X is At that time, R 4 and R 5 Each is independently selected from H, linear or branched alkyl groups comprising 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms, and most preferably any one of methyl, ethyl, or propyl; linear or branched alkenyl groups comprising 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms; halogen-substituted alkyl groups comprising 1 to 8 carbon atoms; alkoxy groups comprising 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms; aryl groups comprising 6 to 12 carbon atoms, preferably 6 to 8 carbon atoms; and alkylaryl groups comprising 7 to 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:

[0024] (IB)

[0025] in:

[0026] R 1 and R 2 Independently selected from linear or branched alkyl groups containing 1 to 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,

[0027] n 1 n is an integer equal to or greater than 1 and n 2 For one, preferably n 1 From about 1 to about 5, and

[0028] Z 2 For compounds derived from diols or polyols with a oxidation state of n 1 +n 2 Part of it and has the following general formula:

[0029]

[0030] Where R is selected from:

[0031] or

[0032]

[0033] and each of them R 6 Independently, it is H or an alkyl group with 1 to 4 carbon atoms, x is 0 or ≥1, preferably 1 to 4, more preferably x=1, y is 2 or 3; z is an integer from 2 to 5; and m ≥ 1, preferably m=1.

[0034] This article also provides methods for preparing these compounds.

[0035] The 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:

[0036] (II)

[0037] Where R 1 and R 2 As defined.

[0038] Compounds of formula (IA) can also be prepared by reacting a dialkylphosphine halide of formula (III) with an aliphatic diol, wherein formula (III) is:

[0039] (III)

[0040] and R 1 and R 2 As defined, and A is chlorine or bromine.

[0041] The phosphorus-containing diols and / or polyols of the present invention, such as those of formula IB, can be prepared by reacting the dialkylphosphine halide of formula (III) with aliphatic diols and / or polyols.

[0042] The reactive monohydroxy functional dialkylphosphinate of the present invention has a high phosphorus content, good hydrolytic and thermal stability, exhibits good compatibility with diol and / or polyol components in rigid polyurethane foam forming systems, and can be used as a highly efficient reactive flame retardant in rigid polyurethane foam.

[0043] The present invention further provides a flame-retardant rigid polyurethane comprising reactive residues following the reaction of the phosphorus-containing monohydroxy functionalized compound in a rigid polyurethane foam forming system to form a rigid polyurethane foam. The phosphorus-containing monohydroxy functionalized compound described herein may be used alone or in premixes with each other and / or with other flame retardants (including halogenated and phosphorus-containing flame retardants) in the rigid polyurethane foam forming system.

[0044] All the above and other features and advantages of the present invention will be better understood by the following illustrative and non-limiting detailed description of its preferred embodiments.

[0045] Detailed description of preferred embodiments

[0046] In one embodiment, the monohydroxy-functional dialkylphosphinate of formula (IA) may be more specifically those of formula (IA-1) or (IA-2), wherein formula (IA-1) is:

[0047] (IA-1)

[0048] Where R 1 and R 2 Z, k and R 3 As defined above; and,

[0049] Equation (IA-2) is:

[0050] (IA-2)

[0051] and R 1 R 2 R 4 and R 5 As defined above.

[0052] 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

[0053]

[0054] Formula (IV)

[0055] in:

[0056] R 4 and R 5 As defined above.

[0057] In another embodiment of this document, 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):

[0058] (V)

[0059] Among them, Z and R 3 The subscript k is defined as above.

[0060] The phosphorus-containing diols and / or polyols of the present invention, such as those of formula (IB), are prepared by reacting a dialkylphosphine halide of formula (III) with an aliphatic diol or polyol.

[0061] The dialkylphosphonic acid (II) and dialkylphosphonic halogen (III) used as initial materials in the method of this invention are mostly 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 entire contents of which are incorporated herein by reference.

[0062] The specific oxacyclopropane compound used in the method for preparing the compounds of formula (IA) or more particularly (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.

[0063] The specific aliphatic diol used in the method for preparing compounds of formula (IA) or more particularly (IA-1) or (IA-2) of the present invention is 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 with a molecular weight of up to 700.

[0064] The aliphatic diols and / or polyols used in the method 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 to 6 (preferably 2, 3 and 4) and a molecular weight preferably from about 100 to about 700. Specific aliphatic diols and / or polyols can be selected from non-polymeric polyols such as trimethylolpropane, trimethylolethane, or glycerol.

[0065] 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) with suitable reactants (e.g., alcohols, amines, and acids) containing one or more active hydrogen atoms; more particularly, the reactants may be selected from diols, triols, phenolic 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) (e.g., adipic acid, phthalic acid, etc.) with diols or triols. The aliphatic diols and / or polyols used in the methods for preparing the phosphorus-containing monools, diols, or polyols of the present invention are selected from polymeric diols and / or polyols such as polyether polyols, polyester polyols, and mixtures thereof.

[0066] In a preferred embodiment of the invention, the reaction of dialkylphosphonic acid (II) with an oxacyclopropane compound takes place in an excess of oxacyclopropane medium in the presence or absence of an organic solvent such as tetrahydrofuran, 1,4-di(II) ... This is carried out in the case of alkyl or toluene.

[0067] The amount of oxopropane compound used in the reaction with monohydroxydialkylphosphonic acid (II) is 5-300% molar excess relative to monohydroxydialkylphosphonic acid, and preferably 50-100% molar excess. Using oxopropane compound in greater than 100% molar excess relative to monohydroxydialkylphosphonic acid is not advisable due to the need to recover large amounts of oxopropane.

[0068] Depending on the dialkylphosphonic acid and oxacyclopropane involved in the reaction, the monohydroxy functional dialkylphosphonates of formula (IA) or more particularly (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.

[0069] For the preparation of a target monohydroxy functional dialkylphosphonate (IA) or more particularly (IA-1) or (IA-2) with the highest possible phosphorus content, it is preferred to react the monohydroxy-dialkylphosphonic acid (II) with ethylene oxide and propylene oxide.

[0070] Therefore, compounds of formula (IA) or more particularly (IA-1) or (IA-2) with particularly valuable properties are those in which R 1 and R 2 Those that are each ethyl.

[0071] The reaction was carried out at 40°C. o C to 120 o Between C, and preferably at 70 o C to 90 o The process is carried out at temperatures between 40°C. Below 40°C... o At temperatures above C, the reaction becomes unacceptably slow. On the other hand, applications above 120°C... o Temperatures of C are not recommended because undesirable decomposition products can form at such temperatures.

[0072] In a preferred embodiment, the reaction of dialkylphosphinohydride (III) with aliphatic diol is carried out in a medium with excess diol.

[0073] The amount of diol compound used in the reaction with dialkylphosphinic halides (III) is typically 2 to 10 moles per mole of dialkylphosphinic halide, and preferably 4 to 8 moles in molar excess. A relatively large excess of the diol is required to minimize the formation of undesirable glycols and hydroxyl-free bis(dialkylphosphinic esters) of the diol. Using a molar excess of more than 10 moles per mole of dialkylphosphinic halide is not advisable due to the need to recover large amounts of diol.

[0074] Depending on the dialkylphosphinic halogen and diol involved in the reaction, the monohydroxy functional dialkylphosphinic esters of formula (IA) or more particularly (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.

[0075] For the preparation of a target monohydroxy functional dialkylphosphonate (IA) or more particularly (IA-1) or (IA-2) with the highest possible phosphorus content, it is preferred to react the dialkylphosphonic halide (III) with the highest phosphorus content with ethylene glycol.

[0076] Therefore, the compound of formula (IA-1) with particularly valuable properties is R. 1 and R2 Each is an ethyl group, k is 1, n is 1, Y is –CH2CH2–, and R 3 Compounds containing hydrogen.

[0077] 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... o Temperatures of C result in low yields. On the other hand, applying temperatures above 120°C is not recommended, as undesirable decomposition products can form at such temperatures. Additionally, catalysts such as MgCl2 or ZnCl2 can be used to accelerate the reaction.

[0078] In a preferred embodiment, the reaction of dialkylphosphinohydride (III) with an 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, mesitylene, and especially toluene and xylene. The effective amount of base used in the method is in the range of 1-1.2 mol per mol of dialkylphosphinohydride (III), and preferably 1-1.05 mol per mol of dialkylphosphinohydride (III).

[0079] Sodium or potassium hydroxide may be used in solid form. Water produced by the reaction between the diol and the base should be removed from the reaction mixture as much as possible before the addition of the dialkylphosphinohydride (III).

[0080] 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):

[0081] (III-A)

[0082] in:

[0083] Where R 1 and R 2 As defined, and where the wavy line represents the bond between the oxygen atom and the diol or polyol.

[0084] The phosphorus-containing diols and / or polyols of the present invention may further include two or more phosphorus-containing groups of formula (III-A), wherein these phosphorus-containing groups may be the same or different.

[0085] 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 that of the dialkylphosphinohydride (III). The base may also be used in excess relative to the dialkylphosphinohydride. The reaction is typically carried out in an inert organic solvent medium. Suitable solvents for phosphorylation are, but not limited to, halogenated hydrocarbons such as dichloromethane, chloroform, or 1,2-dichloroethane. Other suitable solvents are ethers such as diethylphosphinohydride. Alkanes or tetrahydrofurans. Other suitable solvents are hydrocarbons such as hexane or toluene.

[0086] 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, mesitylene, and particularly toluene and xylene.

[0087] The effective amount of the base used in the method is in the range of 1-1.2 mol, and preferably 1-1.05 mol, per mol of dialkylphosphinohydride(III). Sodium hydroxide or potassium hydroxide may be used in solid form. Water produced by the reaction between the diol and / or polyol and the base should be removed from the reaction mixture as much as possible before the addition of the dialkylphosphinohydride(III).

[0088] The amounts of dialkylphosphine halide (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 less-than-stoichiometric amount of dialkylphosphine halide (III) to the diol and / or polyol based on its functionality. In this manner, only a portion of the OH groups in the diol and / or polyol reacts with the dialkylphosphine halide.

[0089] The phosphorus-containing diols and / or polyols of the present invention (also referred to 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 involved in 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.

[0090] The phosphorylation reaction of diols and / or polyols at 0 o C to 100 o Between C, and preferably in 10 o C to 90 o Perform at temperatures between 0°C. Apply below 0°C. oTemperatures of C result in low reaction rates. On the other hand, applying temperatures above 100... o Temperatures of C are not recommended because undesirable decomposition products can form at such temperatures.

[0091] The monohydroxy-functional dialkylphosphonates of the present invention can be used as reactive flame retardants. In one non-limiting embodiment, combining a phosphite (phosphorus ester) compound with the monohydroxy-functional dialkylphosphonate compound of the present invention can be useful. Some non-limiting examples of phosphites are triethyl phosphate, tripropyl phosphate, triisopropyl phosphate, tributyl phosphate, tri-tert-butyl phosphate, tri(2-ethylhexyl) phosphate, trioctyl phosphate, dimethyl methylphosphonate, dimethyl propylphosphonate, diethyl ethylphosphonate, diethyl hydroxymethylphosphonate, diethyl N,N-bis(2-hydroxyethyl)aminomethylphosphonate, tri(chloropropyl) phosphate, tri(dichloropropyl) phosphate, aryl / alkyl phosphate, triaryl phosphate, bisphosphate, oligophosphate, and combinations thereof.

[0092] For rigid polyurethane foams, it is preferred to use the hydroxyl-functional dialkylphosphinate of the present invention, optionally in conjunction with a brominated product containing hydroxyl groups, while for polyisocyanurate foams, it is preferred not to use halogenated flame retardants.

[0093] Flame retardants or flame retardant blends as described herein may be used as is or as mixtures with halogenated or non-halogenated products. More preferably, compositions are made of hydroxyl-functional dialkylphosphinates or blends thereof with phosphate esters combined with reactive brominated products containing hydroxyl groups. For rigid polyurethane (PU) foams, mixtures with brominated products are preferred, while for polyisocyanurate (PIR) foams, pure products are preferred.

[0094] Preferred brominated flame retardants for use in combination with hydroxyl-functional dialkylphosphinates according to the present invention comprise one or more tribromophenol-terminated compounds represented by formula (VI).

[0095]

[0096] Formula (VI)

[0097] in:

[0098] n is an integer ranging from 0 to 5, and more preferably from 0 to 4.

[0099] Such compounds can also be successfully dissolved in hydroxyl-functionalized dialkylphosphonates (the liquid composition provided by this invention) without altering the stability of the composition, allowing the resulting composition to remain in solution form over a long storage period at ambient temperature. Commercially available tribromophenol-terminated compounds of formula (VI) are manufactured by Dead Sea Bromine Group under the trade name F-3014.

[0100] The weight concentration of the hydroxyl-functionalized dialkylphosphonate relative to the total weight of the composition is preferably between 10-60%, and more preferably between 20-40%.

[0101] It has also been discovered that tribromoneopentyl alcohol, a flame retardant represented by the structure of formula (VII), which is solid at room temperature, can also be successfully dissolved in hydroxyl-functionalized dialkylphosphinates (the liquid composition provided by this invention) without altering the stability of the composition, thereby allowing the resulting composition to remain in solution form over a long storage period at ambient temperature.

[0102] (Formula VII). Preferably, the weight concentration of tribromoneopentol is in the range of 10-60%, and more preferably in the range of 20-40%, relative to the total weight of the composition. Tribromoneopentol is available from Dead Sea Bromine Group under the trade name FR-513.

[0103] The compositions of the present invention are particularly useful as flame retardants for polyurethane and polyisocyanurate foams. As explained above, the liquid compositions provided by the present invention are solutions comprising hydroxyl-functionalized dialkylphosphinates of formula (IA, or more particularly (IA-1) or (IA-2)) or (IB) in combination with a compound of formula (VI) or otherwise with tribromoneopentol (VII), and preferably both of formula (VI) and (VII) as solutes of hydroxyl-functionalized dialkylphosphinates of formula (IA, or more particularly (IA-1) or (IA-2)) or (IB), and thus can be directly added to liquid mixtures of reactants used to prepare polyurethane and polyisocyanurate foams, thereby greatly simplifying the blending operation of the mixture and readily obtaining a uniform distribution of the reactants in the mixture.

[0104] In another embodiment of this document, the brominated flame retardant is selected from brominated bisphenol A compounds, brominated bisphenol S compounds, brominated bisphenol F compounds, brominated bisphenol A carbonate oligomers, brominated bisphenol A epoxy resins, end-capped brominated bisphenol A epoxy resins, aliphatic brominated alcohols and diols, dibromonepentyl glycol, brominated phthalates and tetrabromophthalate diols, brominated phosphates, brominated phenols, brominated phthalic acid, and combinations thereof.

[0105] The amount of brominated flame retardant used according to the present invention varies depending on the relationship between the desired degree of flame retardancy and physical properties in the polyurethane foam. However, the brominated flame retardant is typically used in amounts of 1 to 50 parts by weight per 100 parts by weight of polyurethane foam. At amounts less than 1 part by weight, the desired flame retardancy cannot be imparted. At amounts exceeding 50 parts by weight, sufficient flame retardancy is provided but the physical properties of the resulting foam or molded product may be compromised. Therefore, amounts outside the aforementioned range are not preferred. From the viewpoint of maintaining a good balance between flame retardancy and physical properties, the amount practically falls within the range of 3 to 30 parts. Depending on the end-use application, two or more brominated flame retardants may be used in combination.

[0106] Therefore, the flame retardant composition of the present invention can be used as a pre-concentrated concentrate which (by continuous, discontinuous or spray method) can be added to a standard formulation suitable for obtaining rigid polyurethane foam or polyisocyanurate foam.

[0107] In another aspect, the present invention provides compositions of hydroxyl-functional dialkylphosphonates (IA) or more particularly (IA-1) or (IA-2) or IB with halogenated or non-halogenated products (or both).

[0108] In the flame retardant compositions of the present invention, the weight ratio between the compound of general formula IA (IA-1) or (IA-2) and other products is between 1:9 and 9:1, and more preferably between 30-70%. Brominated flame retardants such as tribromopentinol (FR-513) and tribromophenol-terminated compounds represented by formula (VI) may be included in the compositions of the present invention, such that the weight concentrations of the hydroxyl-functional dialkylphosphinate of the present invention, tribromopentinol (VII), and the tribromophenol-terminated compound represented by formula (VI) in the flame retardant compositions of the present invention are in the ranges of 10-50 wt%, 10-50 wt%, and 10-50 wt%, respectively.

[0109] In one embodiment, a flame retardant blend of a monohydroxy-functional dialkylphosphinate of formula (IA), (IA-1), (IA-2), or (IB) with a phosphate compound as described herein is provided, such that the hydroxy-functional dialkylphosphinate and the phosphate component (if present) are blended with a reactive brominated product containing a hydroxyl group (e.g., the non-limiting examples described above).

[0110] The monohydroxy-functional dialkylphosphinate compounds of this invention are highly effective reactive flame retardants when introduced into rigid polyurethane foams, either alone or in combination with phosphate ester compounds. It should be noted that the flame retardant blends of this invention can be used within a wide range of isocyanate indices (abbreviated herein as MDI or TDI). This index refers to the percentage of the stoichiometric amount of isocyanate actually used in the formulation relative to the theoretically required isocyanate.

[0111] The rigid polyurethane foam described herein contains a typical effective amount of flame retardant (i.e., a monohydroxy-functional dialkyl phosphonate). Typically, the phosphonate is applied in an amount providing a total phosphorus concentration in the polymer (i.e., the rigid polyurethane foam) ranging from 0.3 to 15 wt% based on the total weight of the polymer. Preferably, the total phosphorus concentration in the polymer is in the range of 1 to 10 wt%, and more preferably in the range of 1.5 to 5 wt%, based on the total weight of the rigid polyurethane polymer. Most preferably, the amount of phosphonate used in this invention is sufficient to meet the current requirements of the DIN 4102 B2 test and / or LOI flammability test methods.

[0112] Besides rigid foams, another type of foam is available, which is generally classified as semi-rigid, but is included in the general definition of rigid foams herein. These rigid and semi-rigid foams, used as shock-absorbing materials in automotive passenger compartments and elsewhere, are typically produced by reacting a mixture of polyisocyanate with a foam polyol and a crosslinking agent such as trimethylolpropane.

[0113] Although the manufacture of all polyurethane foams (rigid or semi-rigid) involves the same basic chemical reaction between isocyanate and hydroxyl groups, the problems presented to manufacturers differ depending on the type of foam. This difference often relates to the balance that must always be achieved between gas generation and polymer gelation. Many of these problems can be at least partially resolved by appropriately selecting auxiliaries such as blowing agents, catalysts, surfactants, and foam stabilizers.

[0114] The rigid polyurethane foam used herein is made from highly branched, low-equivalent-weight polyether / polyester polyols with a functionality up to 8. A higher concentration of aromatic polyisocyanates is required in rigid polyurethane foams compared to flexible foams. The rigid polyurethane foam obtainable by the method of this invention preferably has a concentration of 10-50 kg / m³. 3 More preferably 20-40 kg / m 3 Core density.

[0115] The rigid foams used in this article are made from both polyether and polyester polyols. For rigid polyurethane foam (PUR), polyols with very high functionality (>3) are used, while for polyisocyanurate (PIR) foam, polyols with lower functionality (<3) are used to compensate for higher brittleness. The polyols used in this article have a molecular weight of 400-800. Rigid polyurethane foams used in this article are characterized by a core foam density of 2.0 psi or less, a closed-cell content in the range of 95-99%, and a density of 6.0-8.0 ft at 10°C. 2 The initial heat resistance of h.°F / Btu.in is mainly used in insulating applications.

[0116] Rigid foams have been used in the automotive, thermal insulation, and many other industries for various purposes. For example, they are used for structural reinforcement, corrosion protection, and damping (attenuation) of sound and vibration. These foams are typically formed by applying a reactive foaming formulation to a part (component) and allowing the formulation to foam in situ. The part is usually already assembled into the vehicle when the foam is applied. This means that the foaming formulation must be easy to mix and dispense, must cure rapidly before flowing away from the part, and preferably must be induced to cure at a moderate temperature. To minimize worker chemical exposure, the formulation is preferably low in volatile organic compounds, particularly volatile isocyanates and amines. The components are preferably stable for long-term storage at room temperature.

[0117] The term semi-rigid, as used in the context of foams, is the standard term in this field. Typically, such foams are formulated with a very low density, while the rigid closed-cell material can withstand loads but is prone to breakage when subjected to impact forces.

[0118] The method for manufacturing rigid polyurethane foam of the present invention may include combining one or more (measurable and pumpable into a conventional mixing vessel) of the diol and / or polyol components and / or the isocyanate components or catalyst and flame retardant materials of formula (IA), (IA-1), (IA-2) and (IB), and then the resulting mixture may be readily moved to a polymerization site for use in molds, sheet operations, etc.

[0119] The reactive flame retardant may also be premixed with a glycol and / or polyol reactant before being combined with the isocyanate reactant. Mixing the reactive flame retardant material and isocyanate, and then combining such a mixture with a glycol and / or polyol reactant, is also within the scope of this invention. However, if the isocyanate and the aforementioned flame retardant material are mixed and allowed to stand at room temperature for a substantial period, a reaction may occur. In one embodiment, the term "reaction product," as used in the claims and this specification, may include reacting the contents of a rigid polyurethane foam forming system in any of the aforementioned methods, and may further include reacting the reactive flame retardant via a prepolymer technique, for example, reacting an excess of isocyanate with a polyol to form an isocyanate-terminated prepolymer, and then further reacting the prepolymer with the reactive flame retardant described herein and optionally a non-reactive flame retardant.

[0120] 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.

[0121] The diols and / or polyols used in the manufacture of the rigid polyurethane foams described herein may include any organic polyols (including diols, polyols), and polyethers, polyesters, polyesteramides, and mannich-based polyols having hydrogen atoms that can react with isocyanates may be used. Typically, these materials have a molecular weight ranging from about 400 to about 800 and have 2 to about 10 or more hydroxyl groups per molecule and a hydroxyl content ranging from about 7.0 to about 15% by weight. They typically have a hydroxyl value of about 350 to as high as 600 or even 700.

[0122] In polyol reactants, the acid value should be less than 10, and generally as close to 0 as possible. The material is simply referred to as a "polyol" reactant. Available diols and / or polyols containing active hydrogen include a large family of addition compounds that are produced by the addition (addition) of ethylene oxide, propylene oxide, 1,2- and 2,3-epoxybutane, or other epoxides to active hydrogen compounds such as diols, glycols, and polyols (examples include ethylene glycol, propylene glycol, glycerol, methyl glucoside, sucrose, sorbitol, hexanetriol, 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 may be added to the indicated base diol, polyol, or amine molecule.

[0123] For example, diols and / or polyols used in the manufacture of rigid foams can also be represented by glycerol, to which sufficient propylene oxide is added to obtain a final hydroxyl content of approximately 8.0%. Such a material would have a molecular weight of approximately 450.

[0124] The technique of controlling flexibility by selecting diol and / or polyol molecules and the amount of subsequently added epoxide alkane is well known in the art.

[0125] In addition to glycols, which can act as base polyol molecules to add alkyl epoxides and thus generate "polyol" molecules for reaction with isocyanates, initial molecules containing primary and / or secondary amine groups with hydrogen atoms capable of reacting with alkyl epoxides may also be used. Again, the amount of alkyl epoxide added depends on the intended use of the final polyurethane product.

[0126] Representative amines that can act as molecules containing active hydrogen to react with epoxides are those having 1 to 6 or more amino nitrogen atoms, examples of which are ethylamine, ethylenediamine (ethylenediamine), diethylenetriamine, triethylenetetramine, tetrapropylenepentamine and other linear saturated aliphatic alkyleneamines. An important requirement is that the epoxide can be added to at least two, and preferably more, i.e., 3 to 8 or 10 active hydrogen sites.

[0127] It is also known that the active hydrogen compounds used in the preparation of polyurethane systems are molecules with hydroxyl groups prepared by esterification-type reactions of polyfunctional acids or anhydrides and polyfunctional alcohols. 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 glycols and / or polyols are ethylene glycol, propylene glycol, butanediol, diethylene glycol, and dipropylene glycol, as well as polyethylene glycol, polypropylene glycol, and glycerol, trimethylolpropane, hexanetriol, pentaerythritol, sorbitol, etc. Where applicable, the above-mentioned acids may be used in the form of anhydrides as needed.

[0128] In the manufacture of polyester polyols, any of various polyfunctional acids or anhydrides or mixtures thereof are reacted with any of diols, glycols, or polyols or mixtures thereof using an excess of hydroxyl groups in stoichiometric amounts, such that the final polyol product comprises primarily hydroxyl terminal groups (terminal groups). The degree of hydroxyl functionality and percentage of hydroxyl groups can be readily altered using one or more techniques known to those skilled in the art to provide a desired polyol.

[0129] In the field and technology of manufacturing rigid polyurethane, a technique known as prepolymer technology is also known. This technique involves carrying out a reaction as part of the manufacturing of rigid polyurethane to produce a prepolymer with increased molecular weight, depending on the stoichiometry used in its production, resulting in either hydroxyl or isocyanate groups as end groups. The final rigid polyurethane product is then prepared using this prepolymer by reacting it with an isocyanate or a polyol, depending on whether the end groups of the prepolymer are hydroxyl or isocyanate groups as described above.

[0130] Broadly speaking, the polyurethanes described herein can be manufactured using any of the following: polyesters having free reactive hydrogen and, in particular, hydroxyl groups, isocyanate-modified polyester prepolymers, polyesteramides, isocyanate-modified polyesteramides, alkylene glycols, isocyanate-modified alkylene glycols, polyoxyalkylene glycols, isocyanate-modified polyoxyalkylene glycols, etc.

[0131] Examples of usable isocyanates include those having two or more isocyanate groups that have been used to date in the manufacture of rigid polyurethane foams. Examples of such isocyanate compounds include aromatic isocyanates, aliphatic isocyanates, and alicyclic isocyanates, and mixtures of two or more such isocyanates, as well as modified isocyanates obtained by modifying such isocyanates. Specific examples of such isocyanates are toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate (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 active hydrogen compounds can also be used.

[0132] In one embodiment, the isocyanate index of the rigid polyurethane foam may range from about 400 to about 150, more preferably from about 375 to about 175, and most preferably from about 350 to about 200.

[0133] As the blowing agent in the rigid 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.

[0134] In this invention, a crosslinking agent is also used, if necessary.

[0135] As a crosslinking agent, compounds having at least two functional groups possessing active hydrogen, such as hydroxyl, primary amino, or secondary amino groups, are preferred. However, in cases where a polyol compound is used as a crosslinking agent, the following is taken into consideration: 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 (polyol (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(methylmercapto)-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.

[0136] When the above-mentioned crosslinking agents are used, even in cases where a large amount of foaming agent is used to manufacture rigid foams with low density, the foaming stability will be good, and it will be possible to manufacture such rigid foams. In particular, when high molecular weight glycols and / or polyols are used, it is possible to manufacture low-density rigid foams that have historically been considered difficult to foam. Furthermore, when crosslinking agents are used, durability is improved compared to when they are not used. In the case of using high molecular weight glycols and / or polyols in this invention, foaming stability can be easily improved, especially when using compounds with relatively high molecular weights, such as at least 4000.

[0137] 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 foamed polyurethane, these and other blowing agents may be used alone or in combination of two or more in a manner known in the art.

[0138] There are no particular restrictions on the amount of foaming agent used, but it is generally in the range of 0.1 to 30 parts by weight per 100 parts by weight of the diol and / or polyol components of the foam-forming composition. Preferably, the amount of foaming agent is such that it provides a foam density of 0.8-2.5 lbs / ft, and preferably 0.9-2.0 lbs / ft.

[0139] The polyurethane foam forming compositions described herein may preferably comprise any and a combination of catalysts known or used to date 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 suitable are metal compounds such as hydrogen tin alkyl carboxylate, 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 ® .

[0140] Many other types of catalysts can be used instead of those listed above, as needed. 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.

[0141] The NCO index used in the manufacture of semi-rigid foams according to the invention is 126-180, and preferably 130-175. The NCO index used in the manufacture of rigid foams according to the invention is 181-350, and preferably 200-300. It is generally understood that the NCO index of polyurethane foam is about 80-130, while the NCO index of isourea ester foam is about 200-350.

[0142] The density of semi-rigid foam can be 8 to 180, preferably 8-80, and most preferably 8-48 kg / m³. 3 Within the range.

[0143] The density of rigid foam can be 8 to 180, preferably 8-80, and most preferably 8-48 kg / m³. 3 Within the range.

[0144] 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-polyoxyalkylene block copolymers). Organic surfactants comprising polyoxyethylene-polyoxybutylene 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 that may be used herein are polyethylene glycol ethers of long-chain alcohols, long-chain allyl sulfates, alkyl sulfonates, tertiary amines or alkanolamine salts of alkyl aryl sulfonic acids, and combinations thereof. Such surfactants are used in amounts sufficient to stabilize the foaming reaction against collapse and the formation of large, uneven cells. Typically, a total surfactant amount of about 0.2 to about 3 wt% of the formulation as a whole is sufficient for this purpose. However, including certain surfactants, such as DABCO DC-5598, available from Air Products and Chemicals, Inc., in higher amounts may be desirable in some embodiments. Therefore, in the formulations of the present invention, surfactants may be included in any amount ranging from 0-6 wt.% based on the diol and / or polyol components.

[0145] Finally, the polyurethane foam forming formulations described herein may include other additives such as fillers and pigments. These, in non-limiting embodiments, 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 manufacturing rigid polyurethane foams using the formulations of the present invention require no further guidance, although such rigid polyurethane foams still fall within the scope of the appended claims but exhibit or benefit from desired properties and / or processing modifications.

[0146] Rigid foams have long been used in the automotive and other industries for various purposes. For example, they are used for structural reinforcement, corrosion protection, and sound and vibration damping. These foams are typically formed by applying a reactive foaming formulation to a part and allowing the formulation to foam in situ. The part is usually already assembled into the vehicle when the foam is applied. This means that the foaming formulation must be easy to mix and dispense, must cure rapidly before flowing away from the part, and preferably initiate curing at a moderate temperature. To minimize worker chemical exposure, the formulation is preferably low in volatile organic compounds, particularly volatile isocyanates and amines. The components are preferably long-term storage stable at room temperature.

[0147] The term semi-rigid, when applied to foams, is the standard term used in this field. Typically, such foams have a glass transition temperature (Tg) between that of rigid and flexible foams.

[0148] The rigid polyurethane foam described herein can be used in the construction and molding of various products such as automotive insulators, panel insulators for wall and roof panel construction, and in-situ cast and spray foamed insulators for wall and roof panels.

[0149] Rigid and semi-rigid polyurethane foams have numerous applications, such as wood-like materials and structural materials. Additionally, rigid polyurethane foams can be used in applications such as: insulators, construction, and packaging; microporous polyurethane foams, such as in footwear and padding; and viscoelastic ("memory") polyurethane foam chemicals, in air filters and as decorative finishes for speakers; foam boards manufactured on laminators with suitable finishes or vapor barriers (moisture barriers); tank and pipe insulators applied via sheeting, molding, and spraying techniques; insulators for refrigeration units, freezers, and water heaters; and for use in flotation and packaging. These insulators may also include window and door insulators.

[0150] The insulator can be used with any structural component, such as a roof or wall. A roof structure is also provided, which includes joists supporting the structural surface layer (main structural slab) and insulator panels (such as those described above located on the structural surface layer), wherein a cover plate is optionally placed thereon, and then a waterproof layer such as roll roofing or asphalt is applied thereon, and then a conventional roof covering such as shingles, tiles, etc. is applied thereon.

[0151] Wall structures are also provided, comprising a frame connected to structural support members (e.g., wood, steel, or concrete beams, single or multiple rigid foam insulation boards (e.g., polyisocyanurate foam boards)), the structural support members being fixed to the exterior of the frame to form a continuous exterior wall, wherein such connection and fixing are achieved by fasteners such as nails, screws, rivets, etc., and wherein there are gaps formed between the structural support members, and the insulation bodies are located within such gaps, and optionally wall panels are fastened to the interior of the frame to form an interior surface.

[0152] The following examples illustrate specific implementations of the preparation of certain compounds of the present invention and the effectiveness of these compounds as reactive flame retardants in rigid polyurethane foams. Example

[0153] Preparation Example 1

[0154]

[0155] Diethylphosphonic acid (779 g, 6.38 mol) was added to a 2-liter jacketed Hastelloy reactor equipped with a mechanical stirrer, oil heater, and positive displacement laboratory pump, and the reactor was 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 the pump over two hours while the temperature was maintained below 65°C. Subsequently, the internal temperature of the reactor was raised to 90°C and maintained at that temperature for three hours. Excess propylene oxide was evaporated, and the residue was evaporated using a scraped-film evaporator at 125°C. o Distillation was carried out under vacuum (300-500 mTorr) at a jacket temperature. The target fraction was collected as a clear, colorless liquid. The yield was 90% relative to the initial diethylphosphonic acid. The product was a mixture of two isomers of the hydroxyl-functionalized ester of diethylphosphonic acid. 31 P NMR (acetic acid-d4, ppm): 66.8 – 67.7; and has an acidity of 0.4 mg KOH / g and a phosphorus content of 15.9%.

[0156] Preparation Example 2

[0157]

[0158] Diethylphosphonic acid (469 g, 3.84 mol) was added to a 1-liter flask equipped with a heating mantle, mechanical stirrer, reflux condenser, suction tube, J-Chem controller and thermocouple, and alkaline gas scrubber. The flask was heated to 80°C, and ethylene oxide from a pressurized gas cylinder was added to the reactor via the suction tube over a period of 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. Nitrogen was further passed through the suction tube to remove excess ethylene oxide. Intermittent distillation of the residue was performed at 150°C and 200 mTorr to produce a clear liquid (400 g). The product was a 2-hydroxyethyl ester of diethylphosphonic acid. 31 P NMR (CDCl3, ppm): 79; and has an acidity of 0.4 mg KOH / g.

[0159] The application of the novel compounds of this invention is demonstrated by their use as flame retardants in standard formulations of rigid polyisocyanurate foam (Application Example 1) and rigid polyurethane foam (Application Example 2). The following components are used in the preparation of the polyurethane foam:

[0160]

[0161] Application Example 1

[0162] The method for preparing rigid polyisocyanurate foam (PIR, NCO index 250) using the new FR product is as follows:

[0163] Foam samples were prepared as follows: Pre-weighed polyol, water, catalyst, stabilizer, and the new FR product from Preparation Example 1 were mixed in a beaker until a homogeneous solution was formed. Pentane was then added to the solution and mixed further. This process was repeated until the desired blowing agent weight was achieved. Immediately after the addition and introduction of MDI, the mixture was stirred at 2500 rpm for 6 seconds and poured into an 8x8x5” (20x20x20 cm) box, allowing it to rise fully. The box was then placed in a fume hood for 24 hours to cure at room temperature. The sample was then removed from the box, cut to the desired size, and tested against DIN 4201 B2 and the limiting oxygen index (LOI).

[0164] Table 1 summarizes the components, parameters, and test results used in foam preparation.

[0165] Table 1. Polyisocyanurate Formulation System

[0166]

[0167] Application Example 2

[0168] The method for preparing rigid polyurethane foam using the new FR product is as follows:

[0169] Pre-weighed polyol, water, catalyst, stabilizer, and flame retardant were placed in a 1000 ml disposable polyethylene (PE) cup and mixed until a homogeneous solution was formed. HFC245fa was then added to the solution and mixed further. This process was repeated until the desired blowing agent weight was achieved. Immediately after adding MDI, the mixture was stirred at 2500 rpm for 3 seconds, and the cup containing all components was then placed on a horizontal platform inside a fume hood, allowing it to rise fully. After 24 hours, the sample was removed from the cup, cut to the desired size, and tested according to DIN 4201 B2 and LOI.

[0170] Table 2 summarizes the components and parameters used in the preparation of rigid polyurethane foam, as well as the test results:

[0171] Table 2. Rigid polyurethane formulation systems

[0172]

[0173] 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 its elements can be substituted with equivalents without departing from the scope of the invention. Furthermore, many changes can be made without departing from its essential scope to make particular scenarios or materials suitable for the teachings of the invention. Therefore, it is intended that the invention not be limited to the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but rather that the invention cover all embodiments falling within the scope of the appended claims.

Claims

1. A flame-retardant rigid polyurethane or polyisocyanurate foam comprising the reaction product of a polyol, an isocyanate, and a flame-retardant effective amount of a monohydroxy functional dialkylphosphinate compound 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, methyl, ethyl, or propyl; and The compound of formula (IA-2) has a phosphorus content of 8-18% by weight.

2. The flame-retardant rigid polyurethane or polyisocyanurate foam as claimed in claim 1, wherein in the compound of formula (IA-2), R 1 and R 2 Each is an ethyl group; and R 4 and R 5 Each is independently selected from H and methyl.

3. The flame-retardant rigid polyurethane or polyisocyanurate foam as described in claim 2, wherein the compound of formula (IA-2) is selected from: , and its mixture.

4. The flame-retardant rigid polyurethane or polyisocyanurate foam as described in claim 3, wherein the compound of formula (IA-2) is a mixture of the following: and .

5. The flame-retardant rigid polyurethane or polyisocyanurate foam according to any one of claims 1 to 4, wherein the reaction product is a reaction product of the following substances: polyol, isocyanate, monohydroxy functional dialkylphosphinate compound of formula (IA-2), and halogenated flame retardants selected from tribromopentyl alcohol (FR-513), tribromophenol-terminated brominated epoxy (F-3014), and combinations thereof, and / or additional phospholipid flame retardants.

6. The flame-retardant rigid polyurethane or polyisocyanurate foam of claim 5, wherein the halogenated flame retardant and / or additional phospholipid flame retardant is tribromopentyl alcohol (FR-513) and tribromophenol-terminated brominated epoxy (F-3014).

7. An article comprising a flame-retardant rigid polyurethane or polyisocyanurate foam as described in any one of claims 1 to 6.

8. A pressurized one-component foam container comprising a polyol, an isocyanate, and a monohydroxy-functional dialkylphosphinate compound of formula (IA-2) as defined in any one of claims 1 to 4.

9. A flame retardant composition comprising: i. Monohydroxy functional dialkylphosphinate 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, methyl, ethyl, or propyl; and The compound of formula (IA-2) has a phosphorus content of 8-18% by weight. ii. Tribromophenol-terminated brominated epoxy compounds (F-3014); and iii. Tribromopentyl alcohol (FR-513).

10. The flame retardant composition of claim 9, wherein in the compound of formula (IA-2), R 1 and R 2 Each is an ethyl group; and R 4 and R 5 Each is independently selected from H and methyl.

11. The flame retardant composition of claim 10, wherein the compound of formula (IA-2) is selected from: , and its mixture.

12. The flame retardant composition of claim 11, wherein the compound of formula (IA-2) is a mixture of the following: and .

13. The flame retardant composition according to any one of claims 9 to 12, wherein the compound of formula (IA-2) has a weight concentration of 10-60% relative to the total weight of the composition, and more preferably 20-40%.

14. The flame retardant composition of claim 13, wherein the compound of formula (IA-2) has a weight concentration of 40% relative to the total weight of the composition.

15. The flame retardant composition according to any one of claims 9 to 14 is used as a flame retardant for polyurethane or polyisocyanurate foam.

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