Phosphoric acid ester compositions for flame-retardant soft PVC with high color stability.

Abstract

The invention relates to mixtures containing at least two substances of the general formula (I) (RO)m(PhO)3-mP=O (I), where m = 1, 2 or 3, in which R corresponds to the residue (formula II) and Ph corresponds to the phenyl group. The mixtures exhibit a unique combination of high colour stability, high flame retardance, and plasticising effect, as a result of which they are recommended for use as flame retardants in PVC compounds, as hydraulic fluids, as lubricant additives, or as additives for paints, adhesives, sealants, or coatings.

Description

1 / 16 Phosphoric acid ester compositions for flame-retardant soft PVC with high color stability.

[0001] Phosphoric acid esters can be used in various technical applications, for example, as lubricants (cf. US 10,414,964 B2), hydraulic fluids (cf. US 6,703,355 B2), plasticizers (cf. DE 1,768,076) or as flame retardants (cf. US 8,129,457 B2).

[0002] The flame retardant effect of phosphoric acid esters has already been demonstrated in several plastics, for example, in PVC (cf. GB 2 302 543 A), in polyolefins (cf. US 11,008,440 B2), in cellulose esters (US 9,000,148 B2), in polyurethanes (cf. US 8,129,457 B2) or in styrene polymers (cf. US 8,026,303 B2).

[0003] Various types of phosphoric acid esters and their use as flame retardants are described in the state of the art. For example, aryl phosphoric acid esters composed of phenol, cresol, tert-butylated phenol, isopropylated phenol, or mixtures thereof are used.

[0004] In addition to triaryl phosphoric acid esters, those skilled in the art are also familiar with mixed alkyl aryl phosphoric acid esters. They are applied, for example, as flame retardants when greater color or heat stability is required (cf. US 5,087,521). This is necessary, among other things, for external plastics, particularly for coatings, cables, tarpaulins, awnings or tents, so that the material does not yellow when exposed to heat. However, the increased color stability comes at the cost of a lesser flame retardant effect compared to triaryl phosphates. Therefore, in US 5,087,521, mixtures of diarylalkyl phosphates and triaryl phosphates are used. Even though this deficiency can be mitigated, according to US 5,087.521, by using mixtures of diarylalkyl phosphates and triaryl phosphates, the poor flame retardant effect of alkyl aryl esters of phosphoric acid remains a disadvantage. The use of two different flame retardant preparations, according to. Petition 870250083076, dated 09 / 15 / 2025, page 11 / 82 2 / 16 the US document 5,087,521, also represents a considerable additional synthetic effort.

[0005] US patent 20120004438 A1 discloses a process for the manufacture of mixed alkylated triaryl phosphates, in which the first step involves the reaction of an alkylated phenol (containing up to 25% dialkylated phenol) with POCl3, generating a product with more than 75% monoalkylphenyl dichlorophosphates. This product then reacts with other alkyl or aryl alcohols to form triesters (cf. claim 1). However, the triesters obtained do not exhibit improved color stabilization compared with prior art flame retardants (cf. Table 23), which further complicates the interpretation of the results, as it was not specifically stated which of the flame retardants according to the invention was used in examples TS-06-9D to TS-06-9F.

[0006] Similarly, mixtures of cyclic aryl phosphates with halogenated compounds are used for the production of PVC materials with color stability and flame retardancy in document EP 0401366 A4. However, the use of halogenated flame retardants is often problematic from a regulatory standpoint.

[0007] The triaryl phosphoric acid ester compositions described in the prior art generally exhibit high flame retardancy in PVC. However, soft PVC materials produced with them have low thermal stability. Another disadvantage of many prior art triaryl phosphoric acid ester compositions is their triphenyl phosphate content. Their hazardous substance properties have led to the requirement for increasingly lower levels of this substance in user-related applications.

[0008] Complex formulations containing a plasticizer, a flame retardant, a stabilizer, and possibly other additives are also known to those skilled in the art for the manufacture of soft PVC with greater thermal stability. For example, document WO 2022 121330 A1 describes the manufacture of flame-retardant soft PVC using a mixture Petition 870250083076, dated 09 / 15 / 2025, page 12 / 82 3 / 16 trioctyl trimellitate (plasticizer), antimony trioxide (flame retardant), a calcium-zinc stabilizer, and calcium carbonate (filler). However, the large number of additives required leads to considerable additional technical effort. Furthermore, antimony trioxide has a negative effect on the transparency of the PVC compound, which is undesirable for some demanding applications.

[0009] The objective of the present invention was therefore to provide a flame retardant preparation which, in addition to a sufficient flame retardant effect, had a plasticizing effect for plastics, in particular for PVC molding compounds, and also high color stability. Preferably, these flame retardants should be present in liquid form at room temperature, through a less complex process and with a low triphenyl phosphate content.

[0010] The said objective is solved by mixtures containing at least two substances of the general formula (I) (RO)m(PhO)3-mP=O (I) with m = 1, 2 or 3, where R corresponds to the residue and Ph corresponds to the phenyl radical.

[0011] In a preferred embodiment of the invention, the mixture according to the invention contains (RO)3P=O, (RO)2(PhO)P=O, (RO)(PhO)2P=O and (PhO)3P=O (triphenyl phosphate, TPP) and, optionally, by-products such as thymol, phenol, catalyst components or by-products, for example.

[0012] The mixtures according to the invention preferably contain 50% by weight or more, with particular preference, 70% by weight or more, with much Petition 870250083076, dated 09 / 15 / 2025, p. 13 / 82 4 / 16 particular preference, 80% by weight or more and, with maximum preference, 90% by weight or more of substances of the general formula (I) (RO)m(PhO)3-mP=O (I), where R, Ph have the meanings shown above.

[0013] In a preferred embodiment, the mixtures according to the invention contain (i) 5 to 90% by weight of (RO)2(PhO)P=O and (ii) 5 to 90% by weight of (RO)(PhO)2P=O, in each case based on the total amount of compounds of formula (I), where m = 0, 1, 2 or 3, where R and Ph have the meanings given above.

[0014] Another preferred embodiment is the mixtures containing: (RO)3P=O (RO)2(PhO)P=O (RO)(PhO)2P=O (PhO)3P=O (TPP) 0 to 30% by weight 5 to 90% by weight 5 to 90% by weight 0 to 30% by weight in each case, based on the total weight of the compounds of formula (I), where m = 0, 1, 2 or 3, preferably, in each case, based on the total weight of the mixture, where R and Ph have the meanings mentioned above.

[0015] Preferably, the mixtures according to the invention contain less than 1% by weight, particularly less than 0.5% by weight, more preferably less than 0.2% by weight, most particularly less than 0.5% by weight and, most preferably, no more than 0.1% by weight of triphenyl phosphate.

[0016] Preferably, the mixtures according to the invention are present as a liquid at 23 °C, since this state facilitates or only allows their use as a flame retardant or in lubricants or hydraulic fluids. Preferably, the mixtures according to the invention have a dynamic viscosity of 20 to 5,000 mPa^s, in particular of 50 to 2,000 mPa^s (in each case at 23 °C).

[0017] Preferably, the mixtures according to the invention have a value Petition 870250083076, dated 09 / 15 / 2025, p. 14 / 82 5 / 16 of acidity less than 5 mg KOH / g, preferably less than 1 mg KOH / g, with particular preference for less than 0.3 mg KOH / g, with even greater preference for less than 0.1 mg KOH / g.

[0018] In an innovative way, it was found that PVC molding compounds containing the mixture according to the invention exhibit high color stability and high flame retardancy. The mixtures according to the invention can be manufactured inventively easily in a new process. A preferred embodiment of the process allows manufacturing in a form where the mixture does not contain triphenyl phosphate or contains only a very small amount.

[0019] Another object of the invention is a process for manufacturing the mixtures according to the invention, comprising the steps of: a) preparing a mixture containing phosphorus oxychloride and thymol, b) reaction of at least part of the mixture of a) at temperatures between 80 °C and 300 °C, with separation of hydrogen chloride, c) addition of phenol to the mixture obtained in b) and further reaction between 100 °C and 300 °C with elimination of hydrogen chloride,

[0020] In an alternative embodiment, at least part of the phosphorus oxychloride is added only in step b). It is also possible that at least part of the thymol is added only in step b).

[0021] Optionally, a catalyst may be added to the mixture prepared in step a) or during step b). Suitable catalysts are NaCl, KCl, LiCl, MgCl2, MgO, CaCl2, AlCls, FeCl3, ZnCl2, TiCl4, SbCl4 and others. Optionally, one or more catalysts may also be added before or during step c).

[0022] The reaction according to step b) is generally carried out in the range of 80 °C to 300 °C, preferably in the range of 100 °C to 250 °C, with particular preference in the range of 100 °C to 200 °C.

[0023] Optionally, between step b) and step c), the reactants (that did not react) from step a) and / or the byproducts formed can be separated by Petition 870250083076, dated 09 / 15 / 2025, page 15 / 82 6 / 16 Distillation. Distillation can be carried out as a batch process or as a continuous process. The distillation temperature is preferably in the range of 80 °C to 250 °C. Particularly preferably, distillation is carried out at the reaction temperature of step b) or at a temperature between 80 °C and the reaction temperature of step b). Distillation takes place in a pressure range of 0.01 mbar to 1013 mbar, preferably in the range of 0.01 mbar to 100 mbar, and particularly preferably in the range of 0.01 mbar to 50 mbar.

[0024] The reaction according to step c) is generally carried out in the range of 100 °C to 300 °C, preferably in the range of 100 °C to 250 °C, with particular preference in the range of 120 °C to 250 °C.

[0025] In an alternative embodiment, at least part of the phenol is added only during the reaction in step c). It is also possible that at least part of the reaction mixture obtained in step b) (directly or after separation by distillation of the reactants from step a) and / or the byproducts formed in step b)) is added during the reaction in step c).

[0026] Optionally, after step c), a separation by distillation of the reactants (unreacted) and / or by-products formed in steps b) and / or c) may occur. Distillation may be carried out as a batch process or as a continuous process. The distillation temperature is preferably in the range of 80 °C to 250 °C. Distillation occurs in a pressure range of 0.01 mbar to 1013 mbar, preferably in the range of 0.01 mbar to 100 mbar, with particular preference in the range of 0.01 mbar to 50 mbar.

[0027] Depending on the application, the mixtures according to the invention may also contain other excipients. Examples of additives include plasticizers, plasticizing polymers, polymer modifiers, stabilizers (e.g., heat stabilizers, light stabilizers, antioxidants), co-stabilizers (e.g., acid scavengers, radical scavengers), internal and external lubricants, viscosity regulators, fillers, color pigments, dyes, flame retardants, flame retardant synergists, blowing agents, and other additives. Petition 870250083076, dated 09 / 15 / 2025, page 16 / 82 7 / 16 functional, such as antistatic agents, nucleating agents, UV protection agents or biocides (see, for example, RD Maier, M. Schiller, Handbuch Kunststoff-Additive, 4th edition, Munich, Carl Hanser publisher, 2016, p. 513 et seq.).

[0028] The mixtures according to the invention are suitable as flame retardants. Another objective of the present invention is, therefore, the use of the mixtures according to the invention as flame retardants.

[0029] The mixtures according to the invention can be used as flame retardants in all flame retardant applications known to those skilled in the art. Preferably, the mixtures according to the invention are used as flame retardants for - Synthetic polymers, such as polyolefins, polyvinyl chloride, polycarbonates, styrene-based (co)polymers, polyamides, polyesters, polyurethanes, elastomers such as NBR, CR, SBR or EPDM, and thermosets such as epoxy resins, unsaturated polyester resins and phenol-formaldehyde resins, - materials of plant origin, such as wood, wood-plastic composites, paper and cardboard, and - materials of animal origin, such as leather.

[0030] In a particularly preferred manner, the mixtures according to the invention are used as flame retardants for polyvinyl chloride (PVC), for example, in PVC molding compounds, i.e., in compositions containing PVC that are present in the form of granules, a powder, a paste or a plastisol.

[0031] Therefore, the invention also relates to compositions, preferably in the form of granules, a powder, a paste or a plastisol, containing a mixture according to the invention and polyvinyl chloride (PVC). Preferably, these PVC molding compounds according to the invention are made of soft PVC. The PVC molding compositions according to the invention can be produced by mixing and combining PVC with the mixtures according to the invention and, if necessary, other auxiliaries, by Petition 870250083076, dated 09 / 15 / 2025, page 17 / 82 8 / 16 For example, stabilizers, in a manner known to themselves (cf., for example, G. Becker, D. Braun, Kunststoff-Handbuch, Polyvinylchloride, Vol. 2 / 2, Munich, Vienna, Carl Hanser Publisher, 1986, p. 829 et seq.) or dispersion in a plastisol or organosol ready for processing.

[0032] The PVC molding composition according to the invention preferably contains 5 to 150 parts by weight, in particular 30 to 70 parts by weight of phosphoric acid esters of formula (I) based on 100 parts by weight of PVC. In a preferred embodiment, the PVC molding composition according to the invention contains 5 to 150 parts by weight, particularly preferably 30 to 70 parts by weight of phosphoric acid esters of formula (I) based on 100 parts by weight of PVC.

[0033] The PVC molding compound according to the invention is used in coatings, films, cables, pipes, hoses, seals, conveyor belts, roofing membranes, adhesive tape films, tarpaulins, awnings and tents.

[0034] Another objective of the invention is the use of the mixtures according to the invention in hydraulic fluids or for the manufacture of hydraulic fluids. The mixtures according to the invention are preferably used in flame-retardant hydraulic fluids.

[0035] Another objective of the invention is the use of the mixtures according to the invention as a lubricant additive. The mixtures according to the invention are preferably used in flame retardant lubricants.

[0036] Another objective of the invention is the use of the mixtures according to the invention as additives for paints, adhesives, sealants and coatings.

[0037] Another objective of the invention is the use of the mixtures according to the invention as heat carriers or in preparations that are used as heat carriers. The mixtures according to the invention are preferably used as heat carriers or in heat carrier preparations in the immersion cooling of electrical components. Petition 870250083076, dated 09 / 15 / 2025, page 18 / 82 9 / 16 In addition to the mixtures according to the invention, the heat carrier preparations contain, for example, other trialkyl phosphates, triaryl phosphates, mineral oils, polyalphaolefins, esters, antioxidants, metal deactivators, flow additives, corrosion inhibitors, foam inhibitors, demulsifiers and / or pour point depressants. Examples Examples of synthesis Example of synthesis 1

[0038] Phosphorus oxychloride (200 parts by weight), thymol (197 parts by weight), and magnesium chloride (0.1 parts by weight) were introduced into a reactor with a stirrer, internal thermometer, nitrogen injection, and reflux condenser. The reaction mixture was heated to 120 °C with stirring and maintained at this temperature until almost no gas formation could be observed. The pressure in the apparatus was gradually reduced from atmospheric pressure to 10 mbar and maintained for 1 h under the final conditions. After the addition of phenol (307 parts by weight), the temperature of the reaction mixture was gradually increased to a final temperature of 160 °C and maintained at this temperature until conversion was complete. Excess phenol was removed at a final temperature of 160 °C and a pressure of 10 mbar. The product mixture was isolated as a viscous liquid (110 mPas at 23 °C). The acidity value was <0.1 mg KOH / g.The product mixture contained 0.6% by weight of (thymylO)3P=O, 12.7% by weight of (thymylO)2(PhO)P=O, 86.3% by weight of (thymylO)-(PhO)2P=O and 0.4% by weight of (PhO)3P=O (“TPP”). Example of synthesis 2

[0039] Phosphorus oxychloride (200 parts by weight), thymol (295 parts by weight), and magnesium chloride (0.1 parts by weight) were introduced into a reactor with a stirrer, internal thermometer, nitrogen injection, and reflux condenser. The reaction mixture was gradually heated to 160 °C with stirring and maintained at that temperature until almost no gas formation could be observed. After the addition of phenol (307 parts by weight), the temperature of Petition 870250083076, dated 09 / 15 / 2025, page 19 / 82 The reaction mixture was gradually increased to a final temperature of 190 °C and maintained at that temperature until conversion was complete. Excess phenol was removed at a final temperature of 190 °C and a pressure of 10 mbar. The product mixture was isolated as a viscous liquid (210 mPas at 23 °C). The acidity value was <0.1 mg KOH / g. The product mixture contained 2.4% by weight of (thymylO)3P=O, 56.0% by weight of (thymylO)2(PhO)P=O, 41.4% by weight of (thymylO)(PhO)2P=O, and 0.2% by weight of (PhO)3P=O (“TPP”). Example of synthesis 3

[0040] Phosphorus oxychloride (200 parts by weight), thymol (394 parts by weight), and magnesium chloride (0.1 parts by weight) were introduced into a reactor with a stirrer, internal thermometer, nitrogen injection, and reflux condenser. The reaction mixture was gradually heated to 160 °C with stirring and maintained at this temperature until almost no gas formation could be observed. After the addition of phenol (186 parts by weight), the temperature of the reaction mixture was gradually increased to a final temperature of 190 °C and maintained at this temperature until conversion was complete. Excess phenol was removed at a final temperature of 190 °C and a pressure of 10 mbar. The product mixture was isolated as a viscous liquid (390 mPas at 23 °C). The acidity value was <0.1 mg KOH / g. The product mixture contained 8.6% by weight of (thymylO)3P=O, 81.1% by weight of (thymylO)2(PhO)P=O, 10.2% by weight of (thymylO)(PhO)2P=O and < 0.1% by weight of (PhO)3P=O (“TPP”).

[0041] The input quantities for synthesis examples S1 to S3 are summarized in Table 1. Table 1: Input quantities and analytical data for synthesis examples S1 to S3. Petition 870250083076, dated 09 / 15 / 2025, p. 20 / 82 11 / 16 Example S1 S2 S3 Weighing [Parts by weight] Phosphorus oxychloride 200 200 200 Thymol 197 295 394 Phenol 307 307 186 Composition [% by weight] (ThymylO)3PO 0.6 2.4 8.6 (ThymylO)2(PhO)PO 12.7 56.0 81.1 (ThymylO)(PhO)2PO 86.3 41.4 10.2 (PhO)3PO (TPP) 0.4 0.2 < 0.1 Determination of the composition of phosphoric acid esters

[0042] Quantitative GC-FID analysis was performed using an Agilent 7890A type GC instrument equipped with a CBSil 5 CB type quartz capillary column (length: 30 m, diameter: 0.32 mm, layer thickness: 3.00 µm). Hydrogen was used as the carrier gas. The sample (dissolved in acetone) was injected in split mode (86:1) at a temperature of 300 °C. The following temperature program was defined: initial temperature of 60 °C, heating rate of 10 °C / min to a temperature of 150 °C, then with a heating rate of 25 °C / min to 280 °C, holding time: 10 min, then at a heating rate of 25 °C / min to a final temperature of 320 °C / min, holding time: 10 min. The evaluation was performed by integrating the corresponding signal separated from the baseline and converting the peak areas into content after prior calibration. Determination of viscosity of phosphoric acid ester composition

[0043] The dynamic viscosity of phosphoric acid esters was measured using an Anton Paar MCR 102 type shear rheometer at the specified temperature, with a shear rate of 200 s-1, according to DIN 53018. Determination of the acidity value of the phosphoric acid ester composition. Petition 870250083076, dated 09 / 15 / 2025, p. 21 / 82 12 / 16

[0044] The acidity value of the samples was determined according to DIN EN ISO 2114 (process B, colorimetric titration with phenolphthalein). For this, the sample was weighed (10 g), dissolved in acetone (200 ml) and water (50 ml), and 2 to 3 drops of a phenolphthalein solution (0.1% by weight in ethanol / water (v / v = 4 / 1)) were added. The sodium hydroxide solution (0.1 mol / l) was titrated from a burette until the color change, from colorless to pink, persisted for at least 10 seconds with stirring. A blank value was measured in the same way, but without sample. Comparative samples of known compositions of phosphoric acid esters

[0045] Table 2 lists the known compositions of phosphoric acid ester that were used as comparative samples for the manufacture of soft PVC. All comparative samples are products of Lanxess Deutschland GmbH. Table 2: Comparison samples used. Comparison Sample Alcohol / Phenol Component Condition at 23 °C Disflamoll® DPK Cresol / Phenol Liquid Disflamoll® TKP Cresol Liquid Disflamoll® 51092 t-butylphenol / phenol Liquid Disflamoll® DPO Phenol / 2-ethylhexanol Liquid Reofos® 65 Isopropylphenol / phenol Liquid Reofos® 50 Isopropylphenol / phenol Liquid Production of soft PVC

[0046] The soft PVC molding compounds used for the test were manufactured in a laboratory laminator. After adding the mixture of all the ingredients of the recipe (see Table 3), it was left on the roller until a layer formed. From the moment the layer formed, Petition 870250083076, dated 09 / 15 / 2025, page 22 / 82 13 / 16 the compounds were put in the rolling mill for another 10 minutes and finally removed as a rolled layer. The rolling temperature was 165 °C.

[0047] Test specimens for LOI determination were produced from laminated strata using a press. The pressing temperature was 170 °C, the pressing duration was 4 minutes for preheating with low pressure (< 10 bar) and 2 minutes with high pressure (> 100 bar). Test specimens with dimensions of 90 x 13 x 4 mm were sawn from 4 mm thick press plates.

[0048] The test specimens for determining the hardness of the compounds (50 x 40 x 6 mm) are pressed for a longer time at the same temperature due to the large thickness of 6 mm. The pressing time was 7 minutes for preheating at low pressure and 3 minutes for pressing the mold at high pressure.

[0049] The test specimens for the color stability test were cut from a thin laminated layer (< 1 mm), which was removed from the laminator after 10 minutes of lamination. Table 3: Components of the recipe for manufacturing soft PVC. Component Function Description Quantity (parts by weight) A PVC Vinnol S4170 100 B Co-stabilizer Drapex 39 2.5 C PVC stabilizer Barostab UBZ 780 RF 2.5 D Flame retardant As shown in Table 4 55 PVC samples were produced in accordance with this standard. Determination of flame retardancy and plasticizing effect.

[0050] The Limiting Oxygen Index (LOI) was used to assess flame retardancy. The LOI is a measure of the fire behavior of plastics and other materials. The LOI is the minimum oxygen concentration in a nitrogen / oxygen mixture below which combustion will occur. Petition 870250083076, dated 09 / 15 / 2025, page 23 / 82 14 / 16 a test specimen can still occur under standardized conditions. The test was performed in accordance with ISO 4589-2. For practical applicability, a value of at least 30 in the test must be obtained.

[0051] The plasticizing effect of phosphoric acid esters was determined by measuring the Shore A hardness of soft PVC compounds containing phosphoric acid esters. The measurement principle is based on the penetration depth of a metal test pin into the material sample for 15 s with a force of 12.5 N. Shore A hardness was determined for test specimens with dimensions 50 x 40 x 6 mm. The Shore hardness measurement was performed according to DIN ISO 7619-1. A Shore A hardness below 95 is an indicator of a softening effect.

[0052] The measurement results are summarized in Table 4. Table 4: Determination of the flame retardancy of the PVC samples produced. Example Flame retardant (Component D) LOI > 30 Shore A hardness < 95 V1 Disflamoll DPK + + V2 Disflamoll TKP + + V3 Disflamoll 51092 + + V4 Disflamoll DPO - + V5 Reofos 65 + + V6 Reofos 50 + + E7 S1 + + E8 S2 + + E9 S3 + +

[0053] The results show that the phosphoric acid ester compositions in PVC according to the invention provide flame retardant properties as good as the comparative products Disflamoll DPK, Petition 870250083076, dated 09 / 15 / 2025, page 24 / 82 15 / 16 Disflamoll TKP, Disflamoll 51092, and Reofos 65. As expected, the LOI of the Disflamoll DPO phosphoric acid alkyl aryl ester PVC compound is significantly lower, which is associated with a smaller flame retardant effect. All flame retardants used achieved Shore A hardnesses below 95 in the test, meaning they had a softening effect. Determination of color stability

[0054] All plastics are subject to an undesirable aging process, which manifests itself in altered mechanical values ​​and a change in color, usually yellowing. The color stability of soft PVC compounds under thermal stress was tested using the Mathis oven (Mathis Thermotester LTE T). Material samples were stored at 180 °C in a convection oven for 30 minutes. Material samples were removed from the hot area of ​​the oven at intervals, so that material samples exposed to the temperature for different time intervals were obtained. Yellowing values ​​(Delta E values) were determined with a Minolta Chroma-Meter CR 400. The measurement was performed according to the DIN-EN-ISO 10545-16 standard. Table 5: Yellowing values ​​after storage in an oven at 180 °C Example Flame Retardant (Component D) Increase in yellowing value after specified time 5 min 10 min 15 min 20 min 25 min 30 min V1 Disflamoll DPK 1.20 8.35 40.68 71.38 63.91 65.21 V2 Disflamoll TKP 0.92 3.25 16.94 66.79 65.38 63.23 V3 Disflamoll 51092 1.00 5.57 18.46 63.49 71.09 63.28 V4 Disflamoll DPO 1.45 9.17 31.13 67.00 75.17 65.76 V5 Reofos 65 0.35 3.75 14.89 41.86 56.33 68.88 V6 Reofos 50 0.33 3.12 15.59 39.08 58.80 60.74 E7 S1 1.72 1.58 1.49 5.68 25.62 44.74 Petition 870250083076, dated 09 / 15 / 2025, page 25 / 82 16 / 16 Example Flame Retardant (Component D) Increase in yellowing value after specified time 5 min 10 min 15 min 20 min 25 min 30 min E8 S2 0.26 0.48 2.07 7.27 15.63 30.91 E9 S3 0.22 0.28 1.12 4.70 9.68 23.01

[0055] The results show that,

Claims

1 / 3 CLAIMS 1. Mixtures characterized by containing at least two substances of the general formula (I) (RO)m(PhO)3-mP=O (I) with m = 1, 2 or 3, where R corresponds to the residue and Ph corresponds to the phenyl radical.

2. Mixtures according to claim 1, characterized by containing (i) 5 to 90% by weight of (RO)2(PhO)P=O and (ii) 5 to 90% by weight of (RO)(PhO)2P=O, where R and Ph have the meanings above.

3. Mixtures according to any one or more of claims 1 or 2, characterized in that they contain less than 1% by weight, preferably less than 0.5% by weight, particularly less than 0.2% by weight and most preferably not more than 0.1% by weight of triphenyl phosphate.

4. Mixtures according to any one or more of claims 1 to 3, characterized in that they are present as a liquid at 23 °C and 1013 mbar, preferably as a liquid with a dynamic viscosity of 20 to 5000 mPa^s, with particular preference for 50 to 1000 mPa^s (in each case at 23 °C).

5. Process for manufacturing mixtures as defined in any one or more of claims 1 to 4 characterized by comprising the steps of: (a) providing a mixture containing at least: - phosphorus oxychloride Petition 870250083076, dated 09 / 15 / 2025, page 27 / 82 2 / 3 - thymol, (b) reacting at least part of the mixture in a) at temperatures between 80 °C and 300 °C, with separation of hydrogen chloride, (c) adding phenol to the mixture obtained in b) and further reacting between 100 °C and 300 °C with elimination of hydrogen chloride.

6. Process according to claim 5, characterized in that, between step b) and step c), a separation by distillation of the reactants of step a) and / or the by-products occurs.

7. Process according to claim 5 or 6, characterized in that, after step c), a separation by distillation of the reactants and / or by-products of steps b) and / or c) occurs.

8. Use of mixtures as defined in any one or more of claims 1 to 4 characterized by being flame retardants, preferably as flame retardants for synthetic polymers, materials of vegetable origin or materials of animal origin and, with particular preference, as flame retardants for polyvinyl chloride (PVC).

9. Molding composition characterized by comprising a mixture as defined in any one or more of claims 1 to 4 and polyvinyl chloride (PVC).

10. Molding composition according to claim 9, characterized in that it contains from 5 to 150 parts by weight, preferably from 30 to 70 parts by weight, of phosphoric acid ester of formula (I) based on 100 parts by weight of PVC.

11. Use of molding compounds as defined in claim 9 or 10, characterized by being intended for the manufacture of coatings, films, cables, pipes, hoses, seals, conveyor belts, roofing membranes, adhesive tape films, tarpaulins, awnings or tents.

12. Use of mixtures as defined in any one or more of claims 1 to 4 characterized by being as a hydraulic fluid.

13. Use of mixtures as defined in any one or more of claims 1 to 4, as defined in Petition 870250083076, dated 09 / 15 / 2025, page 28 / 82 3 / 3, characterized as being a lubricant additive.

14. Use of mixtures as defined in any one or more of claims 1 to 4, characterized in that they are used as an additive for paints, adhesives, sealants or coatings.

15. Use of a mixture as defined in any one or more of claims 1 to 4 characterized by being a heat carrier. Petition 870250083076, dated 09 / 15 / 2025, p. 29 / 82