Dopo derivatives as flame retardant

Abstract

The invention relates to a compound having the following chemical formula (I) and to a flame retardant comprising the compound according to the invention. The present invention further relates to a polyester resin formulation comprising at least one unsaturated crosslinkable polyester resin and at least one flame retardant according to the invention. The present invention further relates to the use of the compound according to the invention as a flame retardant in an unsaturated crosslinkable polyester resin. Finally, the present invention relates to a method for producing the compound according to the invention in which a compound of the formula (III) described herein is reacted with a compound of the formula (IV) described herein in the presence of a catalyst.

Description

[0001] DOPO derivatives as flame retardants

[0002] AREA OF INVENTION

[0003] The present invention relates to novel derivatives of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), processes for their production and their use in flame retardants for polyester resins.

[0004] BACKGROUND OF THE INVENTION

[0005] Due to their flammability, thermoplastic and thermosetting polymers, such as polyesters, polyamides, epoxy resins, and polyurethanes, require the use of flame retardants in many applications. Halogenated compounds, particularly aromatic polybrominated compounds, are typically used as flame-retardant additives in polymers. However, halogenated flame retardants raise environmental concerns. Furthermore, in the event of a fire, halogenated flame retardants form hydrogen halides, which are corrosive and harmful to health.

[0006] Therefore, in the past, halogen-free flame retardants such as aluminum trihydrate, magnesium hydroxide, ammonium polyphosphate, encapsulated red phosphorus, and melamine polyphosphate (containing both phosphorus and nitrogen) have been increasingly used. However, a disadvantage of these halogen-free additive flame retardants is that they are high-melting solids that cannot be sufficiently dissolved or mixed into the curable resins. Furthermore, these substances often have to be used in combination with expandable graphite as synergists.

[0007] Another possibility is the use of 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) as a flame retardant. However, the use of DOPO in unsaturated polyester resins leads to a deterioration of the materials' mechanical properties. This is because DOPO can act as a radical scavenger, thus preventing the desired degree of crosslinking of the unsaturated polyester resins from being achieved.

[0008] It is therefore desirable to develop new flame retardants that do not negatively affect the mechanical properties of polyester resins and are also easier to manufacture. SUMMARY OF THE INVENTION

[0009] According to a first aspect, the present invention relates to a compound with the following chemical formula (I), in the

[0010] R 1 and R 2each are the same or different and each is independently Ci- to C12-alkyl, Ci- to C12-alkenyl, C3- to Cs-cycloalkyl, Cs- to C14-aryl, C7- to C30-alkylaryl groups; wherein one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group,

[0011] R 3 , R 4 , R 5 , R 6 and R 7 are the same or different and each is independently of the other H or Ci to C12 alkyl groups; wherein one or more C atoms may be substituted by an O or N atom and / or one or more H atoms by an OH-

[0012] The group can be substituted; n and m are each independent integers from 0 to 4; and R 8 a C2 to C14 alkenyl group with a terminal double bond.

[0013] According to a second aspect, the present invention relates to a flame retardant comprising the compound according to the first aspect of the invention.

[0014] According to a third aspect, the present invention relates to a polyester resin formulation comprising at least one unsaturated crosslinkable polyester resin and at least one flame retardant according to the second aspect of the invention.

[0015] According to a fourth aspect, the present invention relates to the use of the compounds according to the first aspect of the invention as flame retardants in an unsaturated crosslinkable polyester resin, wherein the resulting polyester resin formulation has the properties as defined in connection with the third aspect.

[0016] Finally, the present invention relates to a method for producing a compound according to the first aspect of the invention, wherein a compound of formula (III) is combined with a compound of formula (IV) is implemented in the presence of a catalyst.

[0017] If a feature of the invention can be present in one or more different embodiments, then the variants described in detail below refer to all (different) embodiments, even if the plural is not explicitly used.

[0018] Preferred embodiments are also disclosed in the dependent claims.

[0019] DETAILED DESCRIPTION OF THE INVENTION

[0020] The inventors have discovered in the course of their research that a group of compounds having the following structure with formula (I) can be used as liquid, reactive flame retardants for polyester resins, the compounds reacting with the chemical "backbone" of the polyester resin without altering or deteriorating the mechanical properties of the polyester resin:

[0021] in the

[0022] R 1 and R 2 each are the same or different and each is independently Ci- to C12-alkyl, Ci- to C12-alkenyl, C3- to Cs-cycloalkyl, Cs- to C14-aryl, C7- to C30-alkylaryl groups; wherein one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group,

[0023] R 3 , R 4 , R 5 , R 6 and R 7are the same or different and are each independently H or Ci to C12 alkyl groups; where one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group; n and m are each independently integers from 0 to 4; and R 8 a C2 to C14 alkenyl group with a terminal double bond.

[0024] Furthermore, the viscosity of polyester resin formulations can be significantly reduced by adding the compounds according to the invention. This reduction in viscosity is normally achieved by adding organic solvents such as styrene. By using the compound according to the invention, the styrene content in polyester resins can be reduced, which offers environmental advantages.

[0025] Furthermore, the liquid state of the flame retardant is advantageous compared to conventional flame retardants such as APP and ATH, which are used as solids. When using solids, high filler contents (up to 60%) are necessary to meet many flame retardancy requirements. At the same time, the solid content also increases the weight of the matrix material, which is disadvantageous for many lightweight applications (composites). As is known to those skilled in the art, the compound described above with formula (I) can also exist in the following tautomeric form:

[0026] This tautomeric form is included in the present application and all other compounds described below with chemical formulas (1a) and (II) can also exist in this tautomeric form.

[0027] It should also be noted that the compounds according to the invention may contain small amounts of impurities from the reaction used to prepare the compound. These impurities may include components such as catalysts, solvents, other reaction products, unreacted DOPO, and other reactants, etc.

[0028] In the compounds with formula (I) R 1 and R 2 Each group can be the same or different. They are each independently Ci- to C12-alkyl, Ci- to C12-alkenyl, C3- to Cs-cycloalkyl, Cs- to C14-aryl, C7- to Cso-alkylaryl groups. One or more carbon atoms can be substituted by an oxygen or nitrogen atom and / or one or more hydrogen atoms can be substituted by an OH group. In a preferred embodiment, R 1 and R 2Each independently of one another are Ci- to Cs-alkyl, preferably Ci- to C3-alkyl. n and m are each independently independent integers from 0 to 4 in the compound with formula (I). In a preferred embodiment, n and m are each independently 0 or 1, preferably both 0.

[0029] R 3 , R 4 , R 5 , R 6 and R 7 are identical or different and each independently of one another H or Ci to C12 alkyl groups; wherein one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group. In one embodiment, R 3 , R 4 , R 5 , R 6 and R 7 the same or different and each independently of each other H, or a linear Ci to CB alkyl group. In a preferred embodiment, R 3 , R 4 , R 5 , R 6 and R7 same or different and each independently selected from H, methyl, ethyl or propyl, wherein preferably at least R 3 , R 5 , and R 7 H is / are. In a particularly preferred embodiment, R are 3 , R 4 , R 5 , R 6 and R 7 each H.

[0030] R 8 is a C2 to C14 alkenyl group with a terminal double bond. In a preferred embodiment, R 8 a linear C2- to C14-alkenyl group with a terminal double bond. In a particularly preferred embodiment, R 8 a linear C2 to Cs alkenyl group with a terminal double bond, preferably a linear C2 to C5 alkenyl group with a terminal double bond.

[0031] In a preferred embodiment, R 1 and R 2 each independently of each other Ci- to CB-alkyl, R 3 , R4 , R 5 , R 6 and R 7 are each independently selected from H, or a linear Ci to CB alkyl group, R 8 is a linear C2 to Cs alkenyl group and n and m are each independently 0 or 1 .

[0032] In a preferred embodiment, R 1 and R 2 each independently of each other Ci- to Cs-alkyl, R 3 , R 4 , R 5 , R 6 and R 7 are each independently selected from H, methyl, ethyl or propyl, R 8 is a linear C2 to Cs alkenyl group and n and m are each independently 0 or 1 .

[0033] In a preferred embodiment, the compound of the present invention has the following chemical formula (1a):

[0034] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 4 , R 5 , R 6 and R 7 Each is independently selected from H, or a linear Ci to Ce alkyl group, and R 8 a linear C2 to Cs-alkenyl group with a terminal double bond.

[0035] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 4 , R 5 , R 6 and R 7 Each is independently selected from H, methyl, ethyl or propyl, and R 8 a linear C2 to Cs-alkenyl group with a terminal double bond.

[0036] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 5 , and R 7 H are and R4 and R 6 Each is independently selected from H, methyl, ethyl or propyl, and R 8 a linear C2 to Cs-alkenyl group with a terminal double bond.

[0037] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 4 , R 5 , R 6 and R 7 H and R are each H and R 8 a linear C2 to Cs-alkenyl group with a terminal double bond.

[0038] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 5 , and R 7 H are and R 4 and R 6 Each is independently selected from H, methyl, ethyl or propyl, and R 8 a linear C2 to C5 alkenyl group with a terminal double bond.

[0039] In a preferred embodiment, the compound of the present invention has the chemical formula (1a), wherein R 3 , R 4 , R 5 , R 6 and R 7 H and R each 8 a linear C2 to C5 alkenyl group with a terminal double bond.

[0040] In a preferred embodiment, the compound of the present invention has the following chemical formula (II): In a preferred embodiment, the compound of the present invention has a viscosity, measured at 25°C, between 5 and 200 Pa·s, such as 10 to 150 Pa·s, 15 to 120 Pa·s, and in particular 20 to 110 Pa·s, measured using a rotational viscometer with a plate-cone attachment (standard method: Physica MCR 302e, plate / cone system 25 mm / 1°, shear rate: 1 s'). 1 , gap distance: 0.058 mm, measuring temp. :25°C, measuring time: 2 min).

[0041] The present invention also relates to a method for producing the inventive procedure.

[0042] Connection Here, a compound of formula (III) is combined with a compound of formula (IV) is implemented in the presence of a catalyst.

[0043] An optional solvent can also be used in the process. Examples of such solvents include heptane, hexane, methylcyclohexane, toluene, xylene, ethylbenzene, or mixtures thereof.

[0044] Basic nucleophiles such as triethylamine (TEA), 4-dimethylaminophenol (4-DMAP), diazabicycloundecene (DBU), or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) can be used as catalysts. In a preferred embodiment, triethylamine (TEA) is used as the catalyst.

[0045] The process can be carried out at temperatures from 80 °C to 200 °C, preferably 130 °C to 180 °C, and particularly 140 °C to 170 °C. Any excess starting material can be removed by distillation. Flame retardant

[0046] The compounds described above can be used in particular in a flame retardant.

[0047] In one embodiment, the flame retardant consists of the compound according to the invention with formula (I), (1a) or (II). In another embodiment, the flame retardant contains the compound according to the invention with formula (I), (1a) or (II) and at least one further additive.

[0048] Preferred additives that may be included in the flame retardant are, for example, heat stabilizers, light stabilizers, ultraviolet light absorbers, antioxidants, antistatic agents, preservatives, adhesion promoters, fillers, pigments, dyes, lubricants, mold release agents, blowing agents, fungicides, plasticizers, processing aids, acid scavengers, dyes, pigments, nucleating agents, wetting agents, dispersants, synergists, mineral fillers, reinforcing agents such as glass fibers, glass flakes, carbon fibers or metal fibers; whiskers such as potassium titanate, aluminum borate or calcium silicate; inorganic fillers and other flame-retardant additives, smoke suppressants and mixtures thereof.

[0049] In a further embodiment, the flame retardant contains, in addition to the compound according to the invention with formula (I), (1a) or (II), at least one additional compound with flame-retardant properties and optionally further additives.

[0050] Additional compounds with flame-retardant properties that can be used together with the compound according to the invention in the flame retardant include, among others, nitrogen-containing synergists such as ammonium polyphosphate (APP), zinc hydroxystannate (ZHS), melamine, melamine phosphate, melamine cyanurate, melamine pyrophosphate, melamine polyphosphate, phosphate and cyanurate derivatives of guanidine and piperazine, phosphazene compounds, polyphophazenes, antimony oxide, silicon dioxide, talc, hydrotalcite, borate salts, hydrated aluminum oxide such as aluminum trihydrate (ATH), boehmite, bismuth oxide, molybdenum oxide, and mixtures of these compounds with zinc, aluminum, and / or magnesium oxide or salts. The flame retardant can also contain several of the aforementioned additional compounds with flame-retardant properties.

[0051] In a preferred embodiment, the flame retardant comprises 5 to 70 wt.% of the compound according to the invention having formula (I), (1a) or (II) and 30 to 95 wt.% of additional compound(s) with flame-retardant properties, based on the total weight of the flame retardant.

[0052] In a preferred embodiment, the flame retardant comprises 20 to 50 wt.% of the compound according to the invention having formula (I), (1a) or (II) and 50 to 80 wt.% of additional compound(s) with flame-retardant properties, based on the total weight of the flame retardant.

[0053] In a preferred embodiment, the flame retardant comprises the compound of formula (I), (1a) or (II) and at least one additional compound with flame-retardant properties selected from the group consisting of aluminium trihydrate (ATH), zinc hydroxystannate (ZHS), ammonium polyphosphate (APP) and / or mixtures thereof, in particular aluminium trihydrate.

[0054] In a preferred embodiment, the flame retardant consists of the compound according to the invention having formula (I), (1a) or (II) and an additional compound with flame-retardant properties and optionally further additives, wherein the additional compound with flame-retardant properties is selected from the group consisting of aluminium trihydrate (ATH), zinc hydroxystannate (ZHS) and ammonium polyphosphate (APP).

[0055] Polyester resin formulation

[0056] According to a third aspect, the present invention relates to a polyester resin formulation comprising at least one unsaturated crosslinkable polyester resin and at least one flame retardant according to the second aspect of the invention.

[0057] The polyester resin formulation of the present invention can have a total phosphorus content of 0.5 to 8 wt.%, preferably 1 to 6 wt.%, and in particular 2 to 4 wt.%. If the compound according to the invention is present in the polyester resin formulation together with an additional compound having flame-retardant properties, the polyester resin formulation can also have a total phosphorus content of 0.5 to 5 wt.%, preferably 0.8 to 4 wt.%, and in particular 1 to 3 wt.%.

[0058] The flame retardant incorporated into the polyester resin formulation of the present invention has an unsaturated carbon-carbon double bond. This double bond can be crosslinked with the unsaturated groups in the polyester resin formulation, resulting in a three-dimensional network with the flame retardant firmly anchored in the resin matrix. This ensures that the incorporated flame retardant can no longer migrate out of the material and thus its effectiveness is not lost. Furthermore, this allows for a synergistic effect between the compound with formula (I), (1a), or (II) and an additional compound with flame-retardant properties.

[0059] In a preferred embodiment, the polyester resin formulation, after curing into a cured polyester, meets criterion V-2 of the Underwriter's Laboratories Standard UL 94 V test, in particular criterion V-1 such as V-0.

[0060] In a preferred embodiment, at least one unsaturated crosslinkable polyester resin is a polycondensation product of an unsaturated dicarboxylic acid and / or its anhydride and a dihydric or polyhydric alcohol.

[0061] Preferred dicarboxylic acids are itaconic acid, maleic acid, fumaric acid, succinic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, and tetrahydrophthalic acid. Preferred unsaturated dicarboxylic anhydrides are itaconic anhydride and maleic anhydride.

[0062] Preferred dihydric alcohols are 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, ethylene glycol, neopentyl glycol, diethylene glycol, and tris-2-hydroxyethyl isocyanurate. Propylene glycol and ethylene glycol are particularly preferred.

[0063] The unsaturated crosslinkable polyester resin used can be present in a solution in reactive diluents, such as styrene.

[0064] In a preferred embodiment, the polyester resin formulation comprises 1 to 90 wt.% unsaturated crosslinkable polyester resin, preferably 10 to 80 wt.%, in particular 15 to 75 wt.%, based on the total weight of the polyester resin formulation.

[0065] The amount of compound of formula (I), (1a), or (II) added to the polyester resin formulation can be varied over a wide range. In a preferred embodiment, the compound is present in the polyester resin formulation at a concentration of 1 to 60 wt.%, preferably 10 to 50 wt.%, and particularly 15 to 45 wt.%, based on the total weight of the polyester resin formulation. Alternatively, the amount of compound of formula (I), (1a), or (II) in the polyester resin formulation is selected such that the composition contains 0.5 to 8 wt.%, preferably 1 to 6 wt.%, and particularly 2 to 4 wt.% phosphorus, based on the total weight of the polyester resin formulation.

[0066] When the compound according to the invention is present in the polyester resin formulation together with an additional compound having flame-retardant properties, the amount of the compound of formula (I), (1a), or (II) in the polyester resin formulation can be selected such that the polyester resin formulation has a total phosphorus content of 0.5 to 5 wt.%, preferably 0.8 to 4 wt.%, and particularly 1 to 3 wt.%. It has been found that sufficient flame protection can be provided even with the aforementioned low phosphorus contents.

[0067] In one embodiment, the flame retardant consists of the compound according to the invention and is present in a concentration of 1 to 60 wt.%, preferably 10 to 50 wt.%, in particular 15 to 45 wt.%, such as 20 to 45 wt.% in the polyester resin formulation, based on the total weight of the polyester resin formulation.

[0068] In a further preferred embodiment, the polyester resin formulation comprises 10 to 40 wt.% of the compound according to the invention with formula (I), (1a) or (II) and 15 to 70 wt.% additional compound(s) with flame-retardant properties, based on the total weight of the polyester resin formulation.

[0069] In a further preferred embodiment, the polyester resin formulation comprises 10 to 30 wt.% of the compound(s) according to the invention with formula (I), (1a) or (II) and 15 to 40 wt.% additional compound with flame-retardant properties, based on the total weight of the polyester resin formulation.

[0070] The formulation may further contain a curing agent. The curing agent may preferably be present in a concentration of 0.5 to 5 wt%, preferably 1 to 4 wt%, such as 1.5 to 2.5 wt% in the polyester resin formulation, based on the total weight of the polyester resin formulation. Suitable curing agents include, in particular, organic peroxides, c-c-labile initiators, and photoinitiators. A suitable curing agent is tert-butyl peroxybenzoate, which is commercially available, among other things, under the trade name Trigonox C.

[0071] In a preferred embodiment, the polyester resin formulation further comprises reactive diluents in a concentration of 1 to 60 wt.%, such as 10 to 40 wt.%, 1 to 30 wt.%, 1 to 28 wt.%, or 10 to 28 wt.%, based on the total weight of the polyester resin formulation. In a preferred embodiment, the reactive diluent is styrene or a (meth)acrylate such as hydroxyethyl methacrylate. Other possible reactive diluents are methyl styrene, vinyltoluene, hexanediol acrylate, triallyl cyanurate, diallyl phthalate, and polyhydric acrylic acid esters and / or mixtures thereof.

[0072] The unsaturated crosslinkable polyester resin used may already contain reactive diluents. In this case, the total concentration of reactive diluents in the polyester resin formulation is preferably 1 to 60 wt.%, 10 to 40 wt.%, 1 to 30 wt.%, 1 to 28 wt.%, or 10 to 28 wt.%, respectively, based on the total weight of the polyester resin formulation.

[0073] The polyester resin formulation according to the invention can be supplemented (in addition to any reactive diluent present in the polyester resin) with a quantity of 0.1 to 30 wt. %, such as 0.1 to 20 wt. %, in each case based on the total weight of the polyester resin formulation.

[0074] In a preferred embodiment, the polyester resin formulation comprises, based on the total weight of the polyester resin formulation:

[0075] 1 to 90 wt% unsaturated crosslinkable polyester resin,

[0076] 1 to 60 wt.% compound with formula (I), (1a) or (II),

[0077] 0.5 to 5 wt% hardening agent, and

[0078] 1 to 60 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0079] In a preferred embodiment, the polyester resin formulation comprises, based on the total weight of the polyester resin formulation:

[0080] 10 to 80 wt% unsaturated crosslinkable polyester resin,

[0081] 10 to 50 wt.% compound with formula (I), (1a) or (II),

[0082] 1 to 4% by weight hardening agent, and

[0083] 10 to 40 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0084] In a preferred embodiment, the polyester resin formulation comprises, based on the total weight of the polyester resin formulation:

[0085] 25 to 75 wt.% unsaturated crosslinkable polyester resin, 15 to 40 wt.% compound of formula (I), (1a) or (II),

[0086] 1 to 3% by weight hardening agent, and

[0087] 15 to 35 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0088] In a preferred embodiment, the polyester resin formulation consists of, based on the total weight of the polyester resin formulation:

[0089] 25 to 75 wt.% unsaturated crosslinkable polyester resin,

[0090] 15 to 40 wt.% compound with formula (I), (1a) or (II),

[0091] 1 to 3% by weight hardening agent, and

[0092] 15 to 35 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0093] In a preferred embodiment, the polyester resin formulation comprises, based on the total weight of the polyester resin formulation:

[0094] 10 to 80 wt% unsaturated crosslinkable polyester resin,

[0095] 5 to 40 wt.% compound with formula (I), (1a) or (II),

[0096] 15 to 70 wt% additional compound(s) with flame-retardant properties, preferably selected from the group consisting of aluminium trihydrate (ATH), zinc hydroxystannate (ZHS), ammonium polyphosphate (APP) and / or mixtures thereof

[0097] 1 to 4% by weight hardening agent, and

[0098] 10 to 40 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0099] In a preferred embodiment, the polyester resin formulation comprises, based on the total weight of the polyester resin formulation:

[0100] 25 to 75 wt.% unsaturated crosslinkable polyester resin,

[0101] 10 to 30 wt.% compound with formula (I), (1a) or (II),

[0102] 20 to 60 wt% additional compound(s) with flame-retardant properties, preferably selected from the group consisting of aluminum trihydrate (ATH), zinc hydroxystannate (ZHS), ammonium polyphosphate (APP) and / or mixtures thereof

[0103] 1 to 3% by weight hardening agent, and

[0104] 15 to 35 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0105] In a preferred embodiment, the polyester resin formulation consists of, based on the total weight of the polyester resin formulation:

[0106] 25 to 75 wt.% unsaturated crosslinkable polyester resin, 10 to 30 wt.% compound of formula (I), (1a) or (II),

[0107] 20 to 60 wt.% additional compound(s) with flame-retardant properties, preferably selected from the group consisting of aluminum trihydrate (ATH), zinc hydroxystannate (ZHS), ammonium polyphosphate (APP) and / or mixtures thereof, 1 to 3 wt.% hardening agent, and

[0108] 15 to 35 wt% reactive diluent, wherein the reactive diluent is preferably styrene.

[0109] The polyester resin formulation according to the invention can further contain the additives described above. In a preferred embodiment, the polyester resin formulation contains glass fibers or synthetic fibers such as aramid fibers or carbon fibers to reinforce the cured polyester resin composition. Furthermore, the polyester composition according to the invention can optionally be modified with plasticizers, fillers, or pigments.

[0110] In a preferred embodiment, the polyester resin formulation has a dynamic viscosity at 25°C of 10 to 8000 mPa, preferably 100 to 5000, measured using a plate-cone rotational viscometer (standard method: Physica MCR 302e, plate / cone system 25mm / 1°, shear rate: 1s'). 1 , gap distance: 0.058 mm, measuring temp. :25°C, measuring time: 2 min).

[0111] The polyester resin formulation according to the invention can be used in particular for the production of flame-resistant, cured polyesters. These polyesters then have a phosphorus component firmly bonded to the resin matrix.

[0112] The invention also relates to the use of the compounds according to the invention as flame retardants in an unsaturated crosslinkable polyester resin, wherein the resulting polyester resin formulation has the properties defined above. Preferably, the polyester resin formulation meets criterion V-2 of the Underwriters Laboratories Standard UL 94 V test, in particular criterion V-1 as well as V-0. Examples

[0113] Example 1) Production of DOPO-AGE

[0114] 34.4 to 51.3 wt% allyl glycidyl ether (AGE) and 0.2 to 0.5 wt% of a catalyst such as triethylamine (TEA) are added, the catalyst optionally at a later stage. The mixture is heated to 140 °C under controlled conditions. At a temperature of 100 °C, the first portion of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) is added, ensuring the temperature does not fall below 90 °C. The reaction temperature is then maintained between 140 and 170 °C. After the DOPO has almost completely reacted, further portions are added, ensuring the temperature does not exceed 170 °C. This step is repeated until a total of 48.4 to 65.3 wt% DOPO has been added and completely reacted. The mixture is then cooled to below 100 °C and any excess AGE is removed by distillation.

[0115] The dynamic viscosity of the compound produced was 51 Pas, measured at 25 °C on an MCR 302e rheometer.

[0116] Example 2) Production of the test specimens:

[0117] The compound obtained in Example 1 according to the invention (hereinafter referred to as DOPO-AGE) is briefly melted at 80 to 100 °C and homogenized and degassed together with styrene, unsaturated crosslinkable polyester resin (UP resin, Palapreg 17-02 from Aliancy), and optionally ATH (Martinal OL-104 LEO from Akrochem) (1 min, 1300 rpm, 1 kPa). A Thinky planetary vacuum mixer is used for this purpose. The hardener (Trigonox C from Nouryon) is then added, and the mixture is homogenized and degassed again (2 min, 1300 rpm, 1 kPa). The resin mixture is poured into a mold and cured in a drying oven using a temperature program. The oven is heated from room temperature to 120 °C at a rate of 1.67 K / min and held at 120 °C for 45 min. The temperature is then increased to 150 °C at a rate of 1 K / min and held at this temperature for 2 hours. The material is then cooled to room temperature, and the test specimens are milled from the plate in rod form according to UL94.

[0118] The composition of the different manufactured polyester resin formulations / test specimens is listed in Table 2. The specified phosphorus content of the formulations was calculated.

[0119] Example 3) Measurement of flame-retardant properties:

[0120] The test specimens produced in Example 2 were tested according to the Underwriters Laboratories standard UL 94 V (Vertical Burning Test). In this test, the vertically clamped specimens are flamed at their lower end for 10 seconds. After the flame extinguishes, the process is repeated for another 10 seconds. This is performed on five specimens. The burning and glowing times are recorded, and the total duration is calculated. It is also noted whether any droplets fall from the specimen and ignite the cotton underneath. UL 94 V ratings range from V-2 to the highest rating, V-0. For a V-0 or V-1 rating, the cotton must not be ignited by glowing or burning droplets. V-2 allows the cotton to ignite.

[0121] The test criteria are clearly listed in Table 1 below. Table 2

[0122] The unsaturated polyester resin (UP resin) used is Palapreg P17-02 with a theoretical styrene content of 35%. The amount of UP resin listed in the table therefore also contains styrene. Styrene was also added to some of the formulations. Thus, the total styrene content of the formulation is the sum of the amount contained in the UP resin and the additional amount of UP resin added. Trigonox C was used as the hardener.

[0123]

[0124] The example data in Table 2 show that when using the compound according to the invention (DOPO-AGE) without an additional compound with flame-retardant properties (synergists), even low phosphorus contents are sufficient to achieve UL94 V-0 (entry 3). The data show that the amount of flame retardant required to achieve V-0 in an identical resin matrix is ​​also strongly dependent on the amount of styrene added, and therefore on the entire UP resin formulation (entries 4 & 5). It can therefore be assumed that the use of lower amounts of DOPO-AGE in other systems also leads to a V-0 classification. When using ATH as the sole flame retardant, amounts of 40 to 50 wt% in the example formulation are necessary to achieve V-0 (entries 6 & 7). This has a significant impact on the mechanical properties (su) of the test specimens.Furthermore, the addition of these high amounts of ATH significantly increases the weight of the test specimens. By adding DOPO-AGE, the proportion of ATH required to achieve V-0 can be considerably reduced (entries 9 & 10).

[0125] Example 4) Measurement of mechanical and rheological properties:

[0126] The test specimens produced in Example 2 are further tested for their mechanical properties. The measurement results of the mechanical characteristics are shown in Table 3.

[0127] The flexural modulus and flexural strength of the polyester resin test specimens were determined using a 3-point bending test according to ISO 178.

[0128] The dynamic viscosity at 25°C was determined using a plate-cone rotational viscometer (rheometer MCR 302e) using the standard method: Physica MCR 302e, (plate / cone system 25mm / 1°, shear rate: 1s') 1, gap spacing: 0.058 mm, measuring temperature: 25°C, measuring time: 2 min) determined.

[0129] Test specimens measuring 55 x 10 mm were milled from the manufactured plates, and the Tg was determined by DMA measurement on an EPLEXOR 500 N (GABO) by evaluation according to tan θ. (Parameters: 50–200 °C, heating rate 3 K / min, f = 1 Hz, dynamic strain = 0.5%) Table 3

[0130] The compounds according to the invention can be used as liquid, reactive flame retardants for polyester resins, wherein the compounds react with the chemical “backbone” of the polyester resin without altering or deteriorating the mechanical properties of the polyester resin:

[0131] The mechanical properties of the cross-linked polyester resin, particularly the flexural modulus, are strongly influenced by the addition of the flame retardant ATH. Using 50 wt% ATH, which corresponds to the amount required to achieve V-0, the modulus almost doubles (entries 1 & 7), and the elongation at break decreases slightly. With the addition of DOPO-AGE, the modulus remains virtually unaffected (entries 1-5), while the elongation at break increases slightly with increasing DOPO-AGE content (entries 2-5). The mixed viscosity decreases with increasing DOPO-AGE content (entries 2-4), while it increases with increasing ATH content (entries 6 & 7). This means that the styrene content can be significantly reduced when using DOPO-AGE compared to ATH, which offers environmental advantages.

[0132] The data from Table 3 show that by using DOPO-AGE with ATH in different ratios depending on the application and requirements of the final product or processing, different properties of the UP resin can be adjusted and V-0 can be achieved in different combinations.

Claims

Claims 1. Compound with the following chemical formula (I), in the R 1 and R 2 each are the same or different and each is independently Ci- to C12-alkyl, Ci- to C12-alkenyl, C3- to Cs-cycloalkyl, Cs- to C14-aryl, C7- to C30-alkylaryl groups; wherein one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group, R 3 , R 4 , R 5 , R 6 and R 7 are the same or different and are each independently H or Ci to C12 alkyl groups; where one or more C atoms may be substituted by an O or N atom and / or one or more H atoms may be substituted by an OH group; n and m are each independently integers from 0 to 4; and R 8a C2 to C14 alkenyl group with a terminal double bond.

2. Compound according to claim 1, characterized in that n and m are each independently 0 or 1, preferably both 0.

3. Compound according to one of claims 1 to 2, characterized in that R 3 , R 4 , R 5 , R 6 and R 7 each is independently selected from H, methyl, ethyl or propyl, wherein preferably at least R 3 , R 5 , and R 7 H are.

4. Compound according to one of claims 1 to 3, characterized in that R 3 , R 4 , R 5 , R 6 and R 7 Each is H.

5. Compound according to one of claims 1 to 4, characterized in that R 8 a linear C2- to Cs-alkenyl group, preferably a linear C2- to Cs-alkenyl group.

6. Compound according to any one of claims 1 to 5 with the following chemical formula (II):

7. Flame retardant comprising the compound according to any one of claims 1 to 6.

8. Flame retardant according to claim 7, characterized in that it further comprises at least one additional compound with flame-retardant properties and / or further additives, wherein the at least one additional compound with flame-retardant properties is preferably selected from the group consisting of aluminium trihydrate, zinc hydroxystannate, ammonium polyphosphate and / or mixtures thereof.

9. Polyester resin formulation comprising at least one unsaturated crosslinkable polyester resin and at least one flame retardant according to claims 7 or 8.

10. Polyester resin formulation according to claim 9, characterized in that the at least one unsaturated polyester resin is a polycondensation product of an unsaturated dicarboxylic acid and / or its anhydride and a dihydric or polyhydric alcohol, wherein the dicarboxylic acid is preferably selected from the group consisting of itaconic acid, maleic acid, fumaric acid, succinic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid and tetrahydrophthalic acid and / or the alcohol is selected from the group consisting of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, ethylene glycol, neopentyl glycol, diethylene glycol and tris-2-hydroxyethyl isocyanurate.

11. Polyester resin formulation according to one of claims 9 or 10, characterized in that the compound as defined in claims 1 to 6 is present in the formulation in a concentration of 1 to 60 wt.%, preferably 10 to 50 wt.%, in particular 15 to 45 wt.%, based on the total weight of the polyester resin formulation.

12. Polyester resin formulation according to one of claims 9 to 11, characterized in that the formulation further comprises a curing agent and / or a reactive diluent, wherein the curing agent is preferably present in a concentration of 1 to 5 wt% in the polyester resin formulation and / or the reactive diluent is present in a concentration of 1 to 60 wt%, preferably 10 to 40 wt%, in each case based on the total weight of the polyester resin formulation and wherein the reactive diluent is preferably styrene or an acrylate such as hydroxyethyl methacrylate.

13. Polyester resin formulation according to one of claims 9 to 12, characterized in that it has a total phosphorus content of 0.5 to 8 wt.%, preferably 1 to 6 wt.%, based on the total weight of the polyester resin formulation.

14. Use of the compounds according to any one of claims 1 to 6 as a flame retardant in an unsaturated crosslinkable polyester resin, wherein the resulting polyester resin formulation has the properties as defined in any one of claims 9 to 13, wherein preferably the polyester resin formulation meets criterion V-2 of the Underwriter's Laboratories Standard UL 94 V test, in particular criterion V-1 such as V-0. Method for producing a compound according to any one of claims 1 to 6, wherein a compound of formula (III) is combined with a compound of formula (IV) is implemented in the presence of a catalyst.

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