Phosphonate flame retardant and manufacturing method thereof

Abstract

A phosphinic acid ester or a composition of phosphinic acid esters obtainable by or by reacting at least a phosphinic acid of formula (I) with ethylene oxide of formula (II): wherein R1 and R2 are the same or different and independently represent H or a hydrocarbyl group, except R1 and R2 are not each H at the same time, and the hydrocarbyl group is selected from C1-C10 alkyl groups, and wherein R3 is an alkylene group optionally selected from O, O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', O ', O', n and S are substituted by heteroatoms. The phosphinic acid esters or phosphinic acid ester compositions thus obtained can be used as reactive or additive flame retardants to make flame retardant polymers or flame retardant polymer compositions. # imgabs0 #

Description

[0001] The present invention relates to a specific type of phosphinates, which can be obtained by or by reacting at least a phosphinic acid of formula (I) with an ethylene oxide of formula (II), as defined herein below. The present invention also relates to a process for the manufacture of a phosphinate, which comprises reacting at least a phosphinic acid of formula (I) with an ethylene oxide of formula (II), as defined herein below. In addition, the present invention relates to the use of the phosphinates thus prepared as flame retardants for polymers and polymer foams, a process for the preparation of flame-retardant polymers using the phosphinates as starting materials, and a flame-retardant polymer composition comprising a polymer and a phosphinate according to the invention as such.

[0002] It is known that flame retardancy of polymers and polymer foams can be obtained by adding various substances. Most of these flame retardant substances are halogenated, particularly brominated organic compounds. Another commonly used halogenated flame retardant is TCPP (tris(1-chloro-2-propyl)phosphate), which is often incorporated into polyurethane foams in consumer products and household insulation materials and electronic devices. However, despite providing effective flame retardancy, TCPP is not chemically bound to the polymer foam and can escape into the environment over time, resulting in negative toxicological and ecotoxicological effects. In addition, leaching of TCPP flame retardant causes the overall flame retardant effectiveness to decrease over time. Therefore, efforts are ongoing to find alternative non-halogenated and preferably chemically reactive flame retardants for polymers and polymer foams.

[0003] One type of such non-halogenated flame retardants for polymer or foam applications is phosphorus-based and includes several reactive options. Depending on their phosphorus oxidation state, these phosphorus-based flame retardants can be phosphates, phosphonates or phosphinates, each containing a phosphorus-oxygen-carbon bond, i.e., an ester linkage.

[0004] US 4 458 035 describes oligomeric phosphate flame retardants for polyurethane foams, and the phosphate ester has the following formula (1), wherein

[0005] n is 0 to 10,

[0006] R is C1-C 10 (Halo)alkyl and

[0007] R1 and R2 are hydrogen atoms or C1-C 10 (Halo)alkyl.

[0008]

[0009] EP 0 658 580 describes different types of reactive phosphate flame retardants for polyurethanes, and the reactive flame retardants have the following formula (2):

[0010]

[0011] in

[0012] q represents the average chain length from 0.5 to 10,

[0013] R1 represents a specific hydroxyl group of formula (2-a)

[0014] Where R7 is H,

[0015] R2 is a group of formula (2-b)

[0016]

[0017] R3 is a group of formula (2-a)

[0018] wherein R7 is C1-C6, R4 is R1 or R3; R5, R6 and R7 are H atoms or alkyl groups having 1 to 6 carbon atoms,

[0019] m is 0 to 4, and

[0020] n is 1 to 4.

[0021] US 7288577 describes a blend of two different phosphate flame retardants for polyurethanes, consisting essentially of:

[0022] (a) 50% by weight of the blend of butylated triphenyl phosphate, and

[0023] (b) 50 wt% of the blend of poly(ethylethyleneoxy)phosphate.

[0024] WO 2014 206487 A1 describes aromatic phosphonate flame retardant compounds for cured epoxy resin compositions, and such resin compositions can be used as adhesives, for electronic circuit component manufacturing, or for structural member manufacturing for the transportation and construction industries. According to WO 2014 206487 A1, the phosphonate flame retardant compound can be a phosphonate having a hydroxyalkyl group.

[0025] Although the previous patent disclosures have mentioned some highly effective and commonly used reactive phosphorus-based flame retardants, their inherent phosphorus-oxygen-carbon bonds (i.e., ester linkages) may tend to hydrolyze under humid conditions, which in turn leads to negative effects on the polymerization process or final polymer properties. In particular, it is known that during the foaming process, the acid formed by hydrolysis may deactivate the polymerization catalyst and further break the covalent bonds in the polymer foam product, thereby destroying the intended 3-D foam network.

[0026] In addition, in order to meet the industrial requirements for polymer manufacturing processes, reactive flame retardants need to be compatible with the monomer reactants (one or more) and, as a preferred feature, can be stably stored with at least one monomer reactant during storage or transportation. Such compatibility requirements eliminate the feasibility of many reactive phosphorus flame retardants for polymers that are otherwise very effective in flame retardancy.

[0027] Another important parameter to consider for flame retardants in polymer applications is their emission properties. For example, one major application of flame retardant flexible polyurethane foams is seat inserts or headliners in the automotive industry, which require very low amounts of semi-volatile condensable emissions (FOG) and minimized volatile organic components (VOC) in the user environment.

[0028] It is therefore an object of the present invention to provide halogen-free reactive flame retardants which exhibit hydrolytic stability under humid conditions and can be used to prepare effective flame retardant polymers or flame retardant polymer compositions having low FOG / VOC emissions and without reactant compatibility problems.

[0029] Another object of the present invention is to provide flame retardant polymers or polymer compositions which combine excellent flame retardancy, very low FOG / VOC emissions and hydrolytic stability at elevated temperatures.

[0030] These objects are achieved by phosphinates which are obtainable by or by reacting at least a phosphinic acid of the formula (I) with an ethylene oxide of the formula (II):

[0031]

[0032] in

[0033] R1 and R2 are the same or different and independently represent H or a hydrocarbon group, except that R1 and R2 cannot both be H at the same time, and the hydrocarbon group is selected from C1-C 10 alkyl, and wherein

[0034] R3 is an alkylene group, which is optionally substituted by a heteroatom selected from O, N and S,

[0035] The phosphinate has the general structure of formula (III-A), (III-B), (IV-A), (IV-B), (VA), (VB), (VI-A), (VI-B), (VI-C), or (VI-D):

[0036]

[0037]

[0038] Unless otherwise indicated, the term "hydrocarbyl" as used herein indicates an aliphatic, aromatic or alicyclic group, which may be saturated or unsaturated, straight chain or branched, and optionally substituted with heteroatoms (eg, O, N, S).

[0039] In particular, "hydrocarbon group" includes: substituted or unsubstituted C1-C 18 Alkyl groups, substituted or unsubstituted C2-C 18 Alkenyl groups, substituted or unsubstituted C2-C 18 Alkynyl group, substituted or unsubstituted C1-C 18 Alkoxy groups, substituted or unsubstituted C2-C 18 Alkenyloxy groups, substituted or unsubstituted C2-C 18 Alkynyloxy groups, substituted or unsubstituted C6-C 18 Aryl groups, substituted or unsubstituted C7-C 18 Arylalkyl groups, substituted or unsubstituted C3-C 18 Heteroaryl groups, substituted or unsubstituted C3-C 18 Heteroarylalkyl groups, substituted or unsubstituted C3-C 18 Cycloalkyl group, and substituted or unsubstituted C3-C 18 Preferably, the hydrocarbon group in the present invention can be selected from C1-C 10 Alkyl and C6-C8 aryl groups.

[0040] Preferably, R1 and R2 are independently selected from H and C1-C6 alkyl groups. In a preferred embodiment, R1 and R2 are each independently selected from C1-C3 alkyl, and most preferably, both are ethyl. In another preferred embodiment, one of R1 and R2 is H and the other is selected from C1-C3 alkyl (e.g. ethyl).

[0041] Unless otherwise indicated, the term "alkylene" refers to the divalent analog of a linear or branched alkyl group, which may be optionally substituted with heteroatoms (eg, O, N, S).

[0042] Preferably, R3 is selected from C1-C3 alkylene, i.e., methylene (-CH2-), ethylene (-CH2CH2-) or propylene butylene (-CH2CH2CH2-) groups. More preferably, R3 is methylene (-CH2-).

[0043] In a preferred embodiment, the phosphinates according to the invention are characterized by a phosphorus content of greater than 12% by weight, based on the total weight of the phosphinate.

[0044] In a preferred embodiment, the phosphinates according to the invention are characterized by a phosphorus content of 12.5 to 20% by weight, based on the total weight of the phosphinate.

[0045] Since the phosphorus structure in phosphorus-containing flame retardants is considered to be the main contributing factor to flame retardancy, the high phosphorus content of the phosphinates of the present invention is advantageous in the intended flame retardant applications. Therefore, the phosphorus content (% w / w) of the phosphinate flame retardant has a significant positive correlation with its flame retardant effectiveness.

[0046] In one embodiment of the present invention, the phosphinates according to the invention are characterized by an OH number of from 10 to 850 mg KOH / g, preferably from 100 to 800 mg KOH / g and more preferably from 200 to 750 mg KOH / g.

[0047] The phosphinates according to the invention can be used as flame retardants and can function as reactive flame retardants for polymers and polymer foams, ie react with monomers in the polymerization or foaming process.

[0048] Alternatively, the phosphinates according to the invention can also function as additive flame retardants which are mixed with the polymer materials used.

[0049] In one embodiment of the present invention, the phosphinate of the present invention has the general structure of formula (III-A'), (III-B'), (IV-A'), (IV-B'), (V-A'), (V-B'), (VI-A'), (VI-B'), (VI-C'), or (VI-D'):

[0050]

[0051] In one embodiment of the present invention, the phosphinates of the present invention have the general structure of formula (III-A') or (III-B').

[0052] The regio- and stereo-selectivity of the desired epoxide ring-opening reaction between the oxirane compound of formula (II) and at least one phosphinic acid compound represented by formula (I) can be directed by changes in the steric hindrance and electronic environment around the oxirane ring, often resulting in the formation of a mixture of phosphinic esters as the resulting reaction products.

[0053] Therefore, the present invention also relates to a composition of phosphinates obtainable by or by reacting at least a phosphinic acid of formula (I) as described above with ethylene oxide of formula (II), said composition comprising at least one phosphinate having the general structure of formula (III-A), (III-B), (IV-A), (IV-B), (VA), (VB), (VI-A), (VI-B), (VI-C), or (VI-D).

[0054] In one embodiment of the present invention, the composition of phosphinates comprises at least one phosphinate having the general structure of formula (III-A'), (III-B'), (IV-A'), (IV-B'), (V-A'), (V-B'), (VI-A'), (VI-B'), (VI-C'), or (VI-D').

[0055] The compositions of phosphinates according to the invention can also be used as a whole as reactive or additive flame retardants and, in particular, can function as reactive flame retardants for polymers and polymer foams by providing individual phosphinates that can react with monomers in the polymerization or foaming process.

[0056] As mentioned above, the reaction of at least the phosphinic acid of formula (I) with the ethylene oxide of formula (II) for preparing the phosphinic ester or the composition of phosphinic ester according to the invention can be carried out in the presence of a catalyst. Preferred types of said catalyst for preparing the phosphinic ester according to the invention are Salts such as ethyltriphenylphosphine iodide

[0057] The reaction of at least the phosphinic acid of formula (I) with the ethylene oxide of formula (II) for preparing the phosphinic ester or phosphinic ester combination according to the invention as mentioned above can be carried out at a temperature of 0° C. up to the boiling point of the reaction mixture, preferably 20° C. to 120° C., particularly preferably room temperature to 120° C.

[0058] According to the invention, the molar ratio of the phosphinic acid of formula (I) to the ethylene oxide of formula (II) in the reaction to obtain the phosphinic ester or the phosphinic ester combination is preferably 2:1 to 1:2, more preferably 1:1.05 to 1:1.8.

[0059] It may be advantageous to use an excess of ethylene oxide of the formula (II) relative to the phosphinic acid of the formula (I) in the reaction in order to produce the phosphinic esters of the invention having reduced acidity.

[0060] The invention also provides flame-retardant polymers obtainable by reacting monomers with at least one phosphinate or a combination of phosphinates according to the invention under polymerization conditions.

[0061] The flame retardant polymer may be a hard plastic selected from the group consisting of polyurethane, epoxy resin, phenolic resin, melamine formaldehyde resin, urea formaldehyde resin and unsaturated polyester.

[0062] Preferably, the flame-retardant polymer is a flame-retardant polyurethane (PUR) which is obtained by reacting a polyol, an isocyanate and at least one phosphinate or a combination of phosphinates according to the invention, optionally in the presence of a polymerization catalyst.

[0063] Suitable polymerization catalysts for producing flame-retardant polyurethanes can be selected from aliphatic tertiary amines (e.g. triethylamine, tetramethylbutanediamine), alicyclic tertiary amines (e.g. 1,4-diaza(2,2,2)bicyclooctane), aliphatic amino ethers (e.g. dimethylaminoethyl ether and N,N,N-trimethyl-N-hydroxyethyl-bisaminoethyl ether), alicyclic amino ethers (e.g. N-ethylmorpholine), aliphatic amidines, alicyclic amidines, urea, urea derivatives (e.g. aminoalkyl ureas, see e.g. EP-A 0 176 013, in particular (3-dimethylaminopropylamine) urea), and tin catalysts (e.g. dibutyltin oxide, dibutyltin dilaurate, tin octoate).

[0064] Advantageously, the phosphinate or phosphinate composition of the present invention is highly compatible with the polyols used to produce flame retardant polyurethanes. Obviously, the phosphinate or phosphinate composition of the present invention can be dissolved in the polyol to form a homogeneous solution, which can be stably stored for up to several months in idle or storage. Using the homogeneous solution as the starting material for polymerization is also beneficial to provide a final PUR product with uniformly distributed flame retardancy.

[0065] For the purposes of the present invention, the term "polyol" refers to compounds having at least two hydrogen atoms capable of reacting with isocyanates. These are compounds having amino groups, thio groups or carboxyl groups, and preferably compounds having hydroxyl groups, in particular 2 to 8 hydroxyl groups.

[0066] Polyols suitable for the purposes of the present invention include those having a molecular weight of 400 to 10 000, in particular those having a molecular weight of 1000 to 6000, preferably 2000 to 6000, and are generally dihydroxy to octahydroxy, preferably dihydroxy to hexahydroxy polyethers or polyesters, or polycarbonates or polyesteramides, as are known per se for the production of homogeneous or foamed polyurethanes and as described, for example, in DE-A 28 32 253.

[0067] Preferred polyester polyols are obtained by polycondensation of polyols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, trimethylolpropane, glycerol, pentaerythritol, diglycerol, glucose and / or sorbitol with dibasic acids such as oxalic acid, malonic acid, succinic acid, tartaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid and / or terephthalic acid. These polyester polyols can be used alone or in combination.

[0068] A further preferred group of polyester polyols for the production of thermosetting flame-retardant polyurethanes are those having two, three or four hydroxyl groups, including ethylene glycol, propylene glycol, trimethylolpropane and pentaerythritol.

[0069] Preferred polyether polyols include, but are not limited to, triols such as glycerol, trimethylolethane (i.e., 1,1,1-tri(hydroxymethyl)ethane), and trimethylolpropane (i.e., 1,1,1-tri(hydroxymethyl)propane); tetraols such as pentaerythritol; pentaols such as glucose; hexaols such as dipentaerythritol and sorbitol; or alkoxylated derivatives of all of the above polyols, such as, preferably, ethoxylated and propoxylated derivatives thereof.

[0070] A particularly preferred polyether polyol is polyoxypropylene triol.

[0071] Other polyols suitable for the purposes of the present invention include those with a low molecular weight of 30 to 400, which are preferably compounds having hydroxyl groups and / or amino groups and acting as chain extenders or crosslinkers. These compounds generally have 2 to 8, preferably 2 to 4 hydrogen atoms capable of reacting with isocyanates.

[0072] Isocyanates suitable for producing the flame-retardant polyurethanes of the present invention can be selected, for example, from aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic polyisocyanates (see, for example, W. Siefken, Justus Liebigs Annalen der Chemie, 562, pp. 75-136), for example, of the formula Q(NCO) r Those of the invention, wherein r is 2 to 4, preferably 2 to 3, and Q is an aliphatic hydrocarbon group having 2 to 18 carbon atoms, preferably 6 to 10 carbon atoms, an alicyclic hydrocarbon group having 4 to 15 carbon atoms, preferably 5 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, preferably 6 to 13 carbon atoms, or an araliphatic hydrocarbon group having 8 to 15 carbon atoms, preferably 8 to 13 carbon atoms.

[0073] Suitable polyisocyanates for the purposes of the present invention are aromatic, alicyclic and / or aliphatic polyisocyanates having at least two isocyanate groups and mixtures thereof. Preference is given to aromatic polyisocyanates such as toluene diisocyanate, methylene diphenyl diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, tris(4-isocyanatophenyl)methane and polymethylene-polyphenylene diisocyanate; alicyclic polyisocyanates such as methylene diphenyl diisocyanate, tolyl diisocyanate; aliphatic polyisocyanates and hexamethylene diisocyanate, isophorone diisocyanate, dimer diisocyanate, 1,1-methylenebis(4-isocyanatocyclohexane-4,4'-diisocyanatodicyclohexylmethane isomer mixture, 1,4-cyclohexyl diisocyanate, and lysine diisocyanate and mixtures thereof.

[0074] Polyisocyanates readily available in the industry, such as 2,4- and 2,6-toluene diisocyanate, are generally particularly preferred.

[0075] For the purposes of the present invention, flame-retardant polyurethanes can be linear PURs, produced, for example, from diols and diisocyanates, or crosslinked PURs, produced, for example, by converting triisocyanate-diisocyanate mixtures using triol-diol mixtures. The properties of flame-retardant polyurethanes can vary within wide ranges. Depending on the degree of crosslinking and / or the isocyanates or OH components used, thermosets, thermoplastics or elastomers are obtained.

[0076] The flame-retardant polyurethanes according to the invention can be used as flexible or rigid foams or alternatively as molding compounds for molding, as casting resins (isocyanate resins), as (textile) elastic fibers, polyurethane coatings and as polyurethane adhesives.

[0077] The present invention also provides a flame retardant polyurethane foam, which is foamed by reacting the polyol, isocyanate and phosphinate or phosphinate composition as described above under stirring, optionally in the presence of a blowing agent, a blowing catalyst, a foam stabilizer and / or other additives.

[0078] For the purposes of the present invention, the term "blowing agent" refers to a substance that can provide gas and produce a foam with a microcellular structure in a polyol-isocyanate reaction. Any conventional blowing agent used to produce polyurethane foam is suitable for use herein, including physical blowing agents and chemical blowing agents. Examples of physical blowing agents include butane and carbon dioxide that expand under reduced pressure, as well as short-chain (C5-C6) aliphatic molecules such as pentane or cyclopentane and various hydrofluoroolefins such as 1,3,3,3-tetrafluoropropylene, which are low-boiling liquids. Examples of chemical blowing agents include water and carboxylic acids, which release gas when reacting with isocyanates. A particularly preferred blowing agent is water.

[0079] For the purpose of the present invention, suitable blowing catalysts for producing the flame retardant polyurethane foam of the present invention are preferably selected from amine catalysts (eg, tertiary amines) and organometallic compounds (eg, tin octoate, tin acetate, dibutyltin diacetate, etc.).

[0080] For the purpose of the present invention, the foam stabilizer suitable for producing flame retardant polyurethane foam can be any conventional stabilizer used for controlling and stabilizing polyurethane foam. As a preferred example, the stabilizer can be selected from silicone surfactants.

[0081] For the production of the flame retardant polyurethane foam according to the present invention, other additives may be added to the reactant mixture, including fillers, pigments, light stabilizers, and processing aids.

[0082] The present invention further relates to the use of the flame retardant polyurethane or flame retardant polyurethane foam mentioned above for making door linings, roof linings, seat covers, high resilience foam seats, high resilience foam cushions, rigid foam insulation panels, microcellular foam seals and pads, durable elastic wheels and tires, automotive suspension bushings, electronic potting compounds, high performance adhesives, surface coatings and sealants, synthetic fibers, carpet backings, hard plastic parts and hoses.

[0083] The invention also relates to the use of flame retardant polyurethane or flame retardant polyurethane foam for the manufacture of electrical switch parts, parts in automobile construction, electrical engineering or electronic devices, printed circuit boards, prepreg materials, encapsulation materials for electronic components, in ship and rotor construction, in outdoor GFRP applications, household and sanitary applications and engineering materials.

[0084] Additionally, the phosphinate esters of the invention obtainable by or by reacting at least one phosphinic acid of formula (I) with ethylene oxide of formula (II) can be used as additive flame retardants as such with polymers. The present invention therefore also provides flame-retardant polymer compositions comprising at least one phosphinate of the invention and a polymer.

[0085] The polymer in the above mentioned flame retardant polymer composition may be a thermoplastic polymer, wherein the thermoplastic polymer is preferably selected from the group consisting of polyamide, polycarbonate, polyester, polyvinyl ester, polyvinyl alcohol, polyolefin, styrenic polymer, polyurethane and polyurea.

[0086] Alternatively, the polymer in the flame retardant polymer composition mentioned above can be a hard plastic polymer, wherein the hard plastic polymer is preferably selected from polyurethane, epoxy resin, phenolic resin, melamine formaldehyde resin, urea formaldehyde resin and unsaturated polyester. A preferred example of the hard plastic polymer is polyurethane foam.

[0087] The flame retardant polymer composition may also contain optional additives. Typical amounts of the optional additives are from 0 to 60 wt%, preferably from 1 to 50 wt% and more preferably from 5 to 30 wt%, referred to the total amount of the flame retardant polymer composition.

[0088] Examples of such optional additives include antioxidants, blowing agents, additional flame retardants, light stabilizers, heat stabilizers, impact modifiers, processing aids, slip agents, processing aids, nucleating and clarifying agents, antistatic agents, lubricants such as calcium stearate and zinc stearate, viscosity and impact modifiers, compatibilizers and dispersants, dyes or pigments, anti-drip agents, additives for laser marking, hydrolysis stabilizers, chain extenders, softeners, plasticizers, fillers and reinforcing agents.

[0089] A preferred optional additive for the flame retardant polymer composition is a filler. The filler may be selected from: metal hydroxides and metal oxides, such as magnesium hydroxide, aluminum hydroxide, silicates, preferably layered silicates, such as bentonite, kaolin, muscovite, pyrophyllite, marcasite and talc or other minerals, such as wollastonite, silicon dioxide such as quartz, mica, feldspar and titanium dioxide, alkaline earth metal silicates and alkali metal silicates, carbonates, preferably calcium carbonate and talc, clay, mica, silicon dioxide, calcium sulfate, barium sulfate, pyrite, glass beads, glass particles, wood flour, cellulose powder, carbon black, graphite and chalk.

[0090] Another preferred optional additive for the flame retardant polymer composition is a reinforcing agent, such as reinforcing fibers. These reinforcing fibers are preferably selected from glass fibers, carbon fibers, aramid fibers, potassium titanate whiskers, preferably glass fibers. The mechanical stability of the flame retardant polymer composition can be improved by reinforcing fibers, in particular by glass fibers.

[0091] The phosphinate flame retardant of the present invention and at least one optional additive mentioned above can be incorporated into the polymer component of the flame retardant polymer composition by premixing all components as powders and / or pellets in a mixer and then homogenizing them in a polymer melt in a compounding device (e.g., a twin-screw extruder). The melt is usually drawn out as strands, cooled and granulated. The phosphinate flame retardant of the present invention and at least one optional additive can also be introduced directly into the compounding device separately via a metering system. The phosphinate flame retardant of the present invention and at least one optional additive mentioned above can also be mixed into finished polymer pellets or powders and the mixture can be directly processed to form parts, for example, on an injection molding machine.

[0092] The flame retardant polymer compositions according to the invention are suitable for producing mouldings, such as films, sheets, threads and fibres, for example by injection moulding, extrusion, blow moulding or compression moulding. Example

[0093] Hereinafter, the present invention is described specifically and in more detail with reference to Examples, however the Examples are not intended to limit the present invention.

[0094] method

[0095] High performance liquid chromatography coupled to mass spectrometry (HPLC-MS) was used to determine the molecular composition of the synthesized products in the synthetic examples.

[0096] via 1 H- and 31 P-NMR was used to confirm the structural determination of the regioisomers. The method for separating the individual phosphinate compounds in the product was preparative column chromatography.

[0097] raw material

[0098] Diethylphosphinic acid (DEPS) CAS: 813-76-3 Mw = 122.1 g / mol

[0099] Ethylphosphinic acid (EPOS) CAS: 4363-06-8 Mw = 94.1 g / mol

[0100] (±)-Glycidol, 96 wt% CAS: 556-52-5 Mw = 74.1 g / mol

[0101] Synthesis Example

[0102] General synthetic procedure: {phosphinic acid + glycidol}

[0103] 100 g of phosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The phosphinic acid was heated to [90-150] ° C while stirring and [60-1000] g of glycidol was added via the dropping funnel over a period of eight hours. The mixture was then stirred at [100-180] ° C for another [1-10] h. Although the following Synthesis Examples 1-3 use DEPS and EPOS as the only two phosphonic acids to react with glycidol, the applicant has pointed out that other phosphonic acids and other oxiranes are also suitable for this procedure under similar reaction conditions.

[0104] The main products of Synthesis Examples 1 & 2 and their structures:

[0105] (1) DEPS-glycidol I: isomeric mixture, as indicated below:

[0106]

[0107] (2) DEPS-glycidol II: isomeric mixture, the major isomers are indicated below:

[0108]

[0109] (3) DEPS-glycidol III: isomeric mixture, the major isomers are indicated below:

[0110]

[0111] (4) DEPS-glycidol IV: isomeric mixture, the major isomers are indicated below:

[0112]

[0113] The main products of Synthesis Example 3 and their structures:

[0114] (1) EPOS-glycidol I: isomeric mixture, as indicated below:

[0115]

[0116] (2) EPOS-glycidol II: isomeric mixture, the major isomers are indicated below:

[0117]

[0118] (3) EPOS-glycidol III: isomeric mixture, the major isomers are indicated below:

[0119]

[0120] (4) EPOS-glycidol IV: isomeric mixture, the major isomers are indicated below:

[0121]

[0122]

[0123] Synthesis Example 1: FR1 {DEPS-glycidol}

[0124] 122.1 g of diethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The diethylphosphinic acid was heated to 120° C. while stirring and 115.7 g of glycidol was added via the dropping funnel over a period of eight hours. The mixture was then stirred at 150° C. for another six hours. The light brown viscous product was analyzed by HPLC-MS, which showed the following product composition of our FR1:

[0125] DEPS-Glycidol I: 28%

[0126] DEPS-Glycidyl II: 18%

[0127] DEPS-Glycidyl III: 36%

[0128] DEPS-Glycidyl IV: 16%

[0129] Diglycerin: 2%

[0130] The product had an acid number of <1 mg KOH / g, an OH number of 614 mg KOH / g, a phosphorus content of 13.3% by weight.

[0131] Product 31 P-NMR (DMSO-d6) analysis showed multiple signals in the range of 62.4-61.4 ppm >98 mol%.

[0132] Synthesis Example 2: {DEPS-glycidol}

[0133] 122.1 g of diethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The diethylphosphinic acid was heated to 65° C. while stirring and 123.5 g of glycidol was added via the dropping funnel over a three-hour period. The mixture was then stirred at 120° C. for another 20 hours. The light brown viscous product was analyzed analytically by HPLC-MS, which showed the following product composition:

[0134] DEPS-Glycidol I: 15%

[0135] DEPS-Glycidyl II: 34%

[0136] DEPS-Glycidyl III: 25%

[0137] DEPS-Glycidyl IV: 22%

[0138] Diglycerin: 4%

[0139] The product had an acid number of 2.4 mg KOH / g, an OH number of 631 mg KOH / g, and a phosphorus content of 12.9% by weight.

[0140] Product 31 P-NMR (DMSO-d6) analysis showed multiple signals in the range of 62.4-61.4 ppm >98 mol%.

[0141] Synthesis Example 3: FR2{EPOS-glycidol}

[0142] 119.6 g of ethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. Ethylphosphinic acid was heated to 100 ° C while stirring and 161 g of glycidol was added via a dropping funnel over a period of 2 hours. The mixture was then stirred at 150 ° C for another 8 hours. The colorless liquid transparent product was analyzed analytically by HPLC-MS, which showed the following product composition:

[0143] EPOS-Glycidol I: 16%

[0144] EPOS-Glycidyl II: 30%

[0145] EPOS-Glycidyl III: 28%

[0146] EPOS-Glycidyl IV: 23%

[0147] Diglycerin: 3%

[0148] The EPOS-glycidol product of this Synthesis Example was found to have similar regioisomerization as the DEPS-glycidol products of Synthesis Examples 1 and 2. The product had an acid number of <1 mg KOH / g and an OH number of 700 mg KOH / g, and a phosphorus content of 14.1 wt%.

[0149] Product 31 P-NMR (DMSO-d6) analysis showed multiple signals in the range of 46.0-42.0 ppm >95 mol%.

[0150] Application Examples

[0151] 1. Components used:

[0152] Flame retardant:

[0153] FR-1: Product of Synthesis Example 1

[0154] FR-2: Product of Synthesis Example 3

[0155] Ref-1: From ICL Industrial Products PCF, TCPP (Tris(1-chloro-2-propyl)phosphate), halogenated phosphate

[0156] Ref-2: From Clariant International Ltd OP 550, a non-halogenated, polymeric phosphorus polyol specially designed for flexible polyurethane foams, is a phosphoric acid ester with hydroxyalkyl groups.

[0157] Ref-3: From Clariant International Ltd. OP 560, a non-halogenated, polymeric phosphorus polyol specially designed for flexible polyurethane foams, is a phosphoric acid ester with hydroxyalkyl groups.

[0158] Polyols:

[0159] Polyether polyol (P1): from Covestro AG 1104 or 1108, a medium molecular weight polyoxypropylene triol having an OH number of 56 mg KOH / g

[0160] Polyester polyol (P2): from Covestro AG 60WB01, partially branched polyester polyol based on adipic acid, diethylene glycol and trimethylolpropane, OH number 60 mg KOH / g

[0161] Polymerization catalyst:

[0162] Cat 1: From Evonik Industries EF, stannous catalyst

[0163] Cat 2: From Evonik Industries 29. Stannous octoate catalyst Cat 3: from Momentive Performance Materials Inc. A1, amine catalyst based on bis(2-dimethylaminoethyl) ether

[0164] Cat 4: From Evonik Industries 33. Amine catalyst based on triethylenediamine

[0165] Cat 5: From Huntsman ZF-10, an amine catalyst based on N,N,N′-trimethyl-N′-hydroxyethyl bisaminoethyl ether

[0166] Cat 6: From Evonik Industries E10, amine catalyst based on 1,4-dimethylpiperazine

[0167] Cat 7: from Momentive Performance Materials Inc. A30, amine catalyst based on bis(2-dimethylaminoethyl) ether

[0168] Foam stabilizer:

[0169] S1: From Evonik Industries B 8232, Silicone surfactant

[0170] S2: From Evonik Industries B 8244, Silicone surfactant

[0171] S3: From Evonik Industries B8235, Silicone surfactant

[0172] TDI (Tolyl diisocyanate):

[0173] T80: From Covestro AG T80, 2,4- and 2,6-toluene diisocyanate, 80 / 20 isomer mixture

[0174] T65: from Covestro AG T65, 2,4- and 2,6-toluene diisocyanate, 65 / 35 isomer mixture

[0175] 2. Hydrolysis stability test

[0176] The hydrolytic stability of different flame retardants is determined by measuring the acid value of the blend made of polyol, flame retardant and water during storage at elevated temperatures over time. For this purpose, 90g polyol, 9g flame retardant (10 wt %) and 4.5g water (5 wt %) were homogenized by stirring at 1500rpm for 2 minutes. The acid value was then determined using a 3:1 (v / v) isopropanol / water mixture as a solvent and a 0.1N NaOH (aq.) solution as a titrant. The samples were then stored at 40°C and the acid value was determined after 11, 17 and 28 days. The samples were homogenized by stirring at 1500rpm for 2 minutes and then analyzed. The acid value evolution of the polyol-water blend without the addition of flame retardant was also determined after 11 and 28 days, as shown in the table below.

[0177] Table 1: Hydrolysis stability test: Evolution of the acid value of a mixture of polyols with 10% (m / m) flame retardant and 5% (m / m) water during storage at 40°C

[0178]

[0179]

[0180] Regardless of the polyol type, the inventive example FR-1 does not lead to a significant increase in the acid value of their polyol blends during and after storage for the entire 28 days at 40°C, compared to the reference without flame retardant. This indicates a high hydrolytic stability of FR-1 during storage in the polyol blends, i.e. zero to negligible hydrolysis of FR-1. In contrast, for both polyol types, the acid value of the polyol blends containing the phosphate ester Ref-2 or the phosphate ester Ref-3 increases significantly after only 11 days under the same storage conditions, which can only be explained by the hydrolysis of Ref-2 or Ref-3, respectively.

[0181] 3. Soft polyurethane (PUR) foam formulation and performance testing

[0182] Stannous catalyst, polyol, flame retardant, water, foam stabilizer and amine catalyst are weighed in this order into a dry beaker and premixed for 60 seconds at 500rpm (for polyether polyol formulations) or 1000rpm (for polyester polyol formulations). After adding TDI, the mixture is stirred at 2500rpm for 7 seconds. The resulting material is quickly poured into a paper-lined box-shaped mold (25*26*26cm). The rise time and other observations are recorded during the foaming process. In each comparative (C1-C7) or inventive (I1-I3) embodiment, the foam is cured at room temperature for about 16 hours, then cut and collected for further evaluation.

[0183] The polymerization catalyst, foam stabilizer and TDI were selected for each foam example based on empirical guidance for optimum foamability in each case, details of which are listed in Table 2 below.

[0184]

[0185] Each PUR foam example was then evaluated for flame retardancy and emissions performance, as explained below.

[0186] Evaluation of flame retardancy

[0187] By testing in a horizontal burn test as described in Federal Motor Vehicle Safety Standard 302 (FMVSS 302) with a 30 kg / m 3 The efficiency of the flame retardant is evaluated by the burning behavior of flexible polyurethane foam samples containing the flame retardant at a target density of 1.50 g / cm2. According to the standard, if the flame does not move beyond the 38 mm mark on the specimen but extinguishes within this distance, the sample is given the highest grade (SE, "self-extinguishing"). Lower grades include SE / NBR (self-extinguishing / non-burning grade), SE / B (self-extinguishing / burning grade) and B (burning grade). Five sample specimens are cut from each foam and submitted to the test. The lowest-rated specimen determines the overall grade of the foam.

[0188] Evaluation of emission performance

[0189] Low emissions from materials are particularly important in automotive interior applications. They can be divided into two types: semi-volatile condensable emissions (FOG) and volatile organic compounds (VOC). The emissions of the name FOG are derived from the fogging effect they can have on cold surfaces such as car windshields. They can be quantified according to DIN 75201B: the sample is heated to 100 ° C for 16h in a special device, while the semi-volatile components of the emissions are condensed on the cooled surface and quantified gravimetrically. VOC emissions can be quantified by thermal desorption analysis according to automotive standard VDA 278. The sample in the thermal desorption tube is heated to 90 ° C for 30min, and the condensate is collected in a cold trap, which is then confirmed and quantified via GC / MS according to external standards such as toluene. The emission performance of the new flame retardant described herein is evaluated by measuring both FOG and VOC emissions according to these procedures.

[0190] The flame retardancy and emissions performance of the foam examples tested are compared below and are listed separately according to the type of polyol in the foam.

[0191]

[0192] As shown in the performance data listed in Table 3, Comparative Example C1 (polyether polyurethane foam without flame retardant additive) does not meet the required flame retardancy standards. Comparative Example C2 with 12 php of halogenated reference flame retardant TCPP (Ref-1) provides a polyether polyurethane foam that meets the required flame retardancy standards but exhibits very poor emission properties as reflected in the relevant fogging and VDA 278 parameters. In order to reduce the undesirable emissions of the PUR foam samples incorporating TCPP, Comparative Example C3 reduces the TCPP content to 8 php but fails to achieve the required flame retardancy rating.

[0193] Comparative Example C4 is a non-halogenated reference flame retardant with a reactivity of 4php The polyether polyurethane foam of OP 550 (Ref-2), which meets the required flame retardancy standards, provides lower semi-volatile condensable emissions (ie fogging) compared to C2, but the VOC (ie VDA 278) is still higher than desired.

[0194] Inventive Example I1, a polyether polyurethane foam having a 4php reactive non-halogenated inventive flame retardant (FR-1), not only meets the required flame retardancy standards, but also has minimal emission characteristics in both semi-volatile condensable emissions and VOC measurements.

[0195] Inventive Example 12, a polyether polyurethane foam having a 4php reactive non-halogenated inventive flame retardant (FR-2), is equally excellent as 11 in flame retardancy rating and emission properties.

[0196] Table 4: Performance data of flexible polyurethane polyester (P2) foam formulations

[0197]

[0198]

[0199] As shown in the performance data listed in Table 3, Comparative Example C5 (polyurethane polyester foam) without a flame retardant did not meet the required flame retardancy standards.

[0200] Comparative Example C6 with 8php halogenated reference flame retardant TCPP (Ref-1) provides a polyurethane polyester foam that meets the required flame retardancy standards but exhibits very poor emission properties as reflected in the relevant fogging data and in particular the VDA 278 measurements.

[0201] Advantageously, Example 13 of the present invention, a polyurethane polyester foam having a 6.5 php reactive non-halogenated flame retardant of the present invention (FR-1), not only meets the required flame retardancy standards, but also achieves minimums in both semi-volatile condensable emissions and VOC measurements.

[0202] Based on these experimental data, the technical advantages of the phosphinate flame retardant of the present invention are not limited to hydrolytic stability and compatibility with polyol systems for polymer processing, but also extend to providing flame retardant PUR foams with excellent flame retardancy and minimal emissions during use. It is further pointed out that the flame retardants FR-1 and FR-2 of the present invention show excellent compatibility with each polyol tested, and remain in a liquid state for more than 28 days when stored.

Claims

1. Phosphinic esters obtainable by or by reacting at least a phosphinic acid of the formula (I) with ethylene oxide of the formula (II): in R1 and R2 are the same or different and independently represent H or a hydrocarbon group, except that R1 and R2 cannot both be H at the same time, and the hydrocarbon group is selected from C1-C 10 alkyl, and wherein R3 is an alkylene group, which is optionally substituted by a heteroatom selected from O, N and S, The phosphinate has the general structure of formula (III-A), (III-B), (IV-A), (IV-B), (VA), (VB), (VI-A), (VI-B), (VI-C), or (VI-D):

2. The phosphinate according to claim 1, wherein R1 and R2 are selected from C1-C6 alkyl groups.

3. The phosphinate according to claim 1, wherein one of R1 and R2 is H and the other is selected from C1-C3 alkyl.

4. The phosphinate according to any one of claims 1 to 3, wherein R3 is selected from C1-C3 alkylene.

5. The phosphinate according to any one of claims 1 to 3, wherein R3 is CH2.

6. The phosphinate according to claim 1, wherein the phosphorus content is greater than 12% by weight, based on the total weight of the phosphinate.

7. The phosphinate according to claim 1, wherein the phosphinate has a general structure of formula (III-A') or (III-B'):

8. Use of the phosphinate according to any one of claims 1 to 7 as a flame retardant.

9. A composition of phosphinic esters obtainable by or by reacting at least a phosphinic acid of the formula (I) with an ethylene oxide of the formula (II): in R1 and R2 are the same or different and independently represent H or a hydrocarbon group, except that R1 and R2 cannot both be H at the same time, and the hydrocarbon group is selected from C1-C 10 alkyl, and wherein R3 is an alkylene group, which is optionally substituted by a heteroatom selected from O, N and S, The composition comprises at least one phosphinate having the general structure of Formula (III-A), (III-B), (IV-A), (IV-B), (VA), (VB), (VI-A), (VI-B), (VI-C), or (VI-D):

10. Use of the composition according to claim 9 as a flame retardant.

11. Flame-retardant polymer obtainable by reacting monomers with at least one phosphinate according to any one of claims 1 to 7 or a composition according to claim 9.

12. Flame-retardant polyurethane obtainable by reacting a polyol, an isocyanate and at least one phosphinate according to any one of claims 1 to 7 or a composition according to claim 9.

13. A flame retardant polyurethane foam obtained by reacting a polyol, an isocyanate and a phosphinate according to any one of claims 1 to 7 or a composition according to claim 9, optionally in the presence of a blowing agent, a blowing catalyst, a foam stabilizer and / or other additives.

14. Flame retardant polymer composition comprising at least one phosphinate according to any one of claims 1 to 7 or a composition according to claim 9, and a polymer, wherein the polymer is a thermoplastic polymer or a duroplast polymer and is preferably a polyurethane foam.

15. A process for preparing a phosphinate or a composition of phosphinates, comprising reacting at least a phosphinic acid of formula (I) with an ethylene oxide of formula (II): in R1 and R2 are the same or different and independently represent H or a hydrocarbon group, except that R1 and R2 cannot both be H at the same time, and the hydrocarbon group is selected from C1-C 10 alkyl, and wherein R3 is an alkylene group which is optionally substituted by a heteroatom selected from O, N and S.

16. The method according to claim 15, wherein the molar ratio of the phosphinic acid of formula (I) to the ethylene oxide of formula (II) in the reaction is 2:1 to 1:2, preferably 1:1.05 to 1:1.8.

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