Mixtures Of Diphosphinic Acids And Dialkylphosphinic Acids, A Process For The Preparation Thereof And The Use Thereof

Abstract

The invention relates to mixtures of at least one diphosphinic acid of the formula (I)

##STR00001## in which R.sup.1, R.sup.2 are the same or different and are each independently H, C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene, C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II)

##STR00002## in which R.sup.3, R.sup.4 are the same or different and are each independently C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl and/or C.sub.7-C.sub.18-alkylaryl.

The invention also relates to a process for preparing these mixtures and to the use thereof.

Claims

1.-20. (canceled)

21. A flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber comprising 0.5 to 50% by weight of a mixture of at least one diphosphinic acid of the formula (I) ##STR00005## wherein R.sup.1, R.sup.2 are the same or different and are H, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl or C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene or C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II) ##STR00006## wherein R.sup.3, R.sup.4 are the same or different and are C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl or mixtures thereof, 50 to 99.5% by weight of thermoplastic or thermoset polymer or mixtures thereof, 0 to 55% by weight of additives and 0 to 55% by weight of filler or a reinforcing material, where the sum of the components is 100% by weight.

22. A flame-retardant thermoplastic or thermoset polymer molding composition or polymer molding, film, filament or fiber comprising 2 to 30% by weight of a mixture of at least one diphosphinic acid of the formula (I) ##STR00007## wherein R.sup.1, R.sup.2 are the same or different and are H, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl or C.sub.7-C.sub.18-alkylaryl, R.sup.5 is C.sub.1-C.sub.18-alkylene, C.sub.2-C.sub.18-alkenylene, C.sub.6-C.sub.18-arylene or C.sub.7-C.sub.18-alkylarylene with at least one dialkylphosphinic acid of the formula (II) ##STR00008## wherein R.sup.3, R.sup.4 are the same or different and are C.sub.1-C.sub.18-alkyl, C.sub.2-C.sub.18-alkenyl, C.sub.6-C.sub.18-aryl, C.sub.7-C.sub.18-alkylaryl or mixtures thereof, 60 to 94% by weight of thermoplastic or thermoset polymer or mixtures thereof, 2 to 30% by weight of additives and 2 to 30% by weight of filler or a reinforcing material, where the sum of the components is 100% by weight.

Description

EXAMPLE 1 PREPARATION OF ETHYLPHOSPHINIC ACID

[0109] At room temperature, a three-neck flask with stirrer and jacketed coil condenser is initially charged with 5852 g of tetrahydrofuran and “degassed” while stirring and passing nitrogen through, and all further reactions are executed under nitrogen. Then 70 mg of tris(dibenzylideneacetone)dipalladium and 95 mg of 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene are added and the mixture is stirred for a further 15 minutes, then 198 g of phosphinic acid in 198 g of water are added. The reaction solution is transferred into a 2 l Büchi reactor. While stirring the reaction mixture, the reactor is charged with ethylene to 2.5 bar and the reaction mixture is heated to 80° C. After 56 g of ethylene have been absorbed, the mixture is cooled to room temperature and free ethylene is burnt off.

[0110] The reaction mixture is freed from the solvent on a rotary evaporator at a maximum of 60° C. and 350-10 mbar, 300 g of demineralized water are added to the residue, and the mixture is stirred under nitrogen atmosphere at room temperature for 1 hour. The resulting residue is filtered and the filtrate is extracted with 200 ml of toluene. The aqueous phase is freed from the solvent on a rotary evaporator at a maximum of 60° C. and 250-10 mbar.

[0111] 31P NMR (D.sub.2O, coupled): doublet of multiplet, 36.7 ppm; ethylphosphinic acid.

EXAMPLE 2

[0112] 0.5 mol of ethylphosphinic acid (prepared according to example 1) is initially charged in n-butanol as a solvent and inertized with a nitrogen gas stream while stirring for 30 minutes and heated to 80° C. Acetylene is passed through the reaction solution at 18 l/h and 0.2 mol % of initiator is metered in over 3 hours, and the mixture is left to react a little longer. Thereafter, the acetylene is driven out of the apparatus with nitrogen. After the reaction mixture has been cooled, the solid formed is filtered off with suction and redispersed with acetone, washed and dried in a vacuum drying cabinet at 100° C. for 4 hours.

[0113] In a yield of 65%, 34.8 g of a mixture of ethylene-1,2-bis(ethylphosphinic acid) (99.9% by weight) and diethylphosphinic acid (0.1% by weight) are obtained.

EXAMPLE 3

[0114] 0.5 mol of ethylphosphinic acid (prepared according to example 1) is initially charged in n-butanol and inertized with a nitrogen gas stream while stirring for 30 minutes and heated to 85° C. Acetylene is passed through the reaction solution at 20 l/h, and 0.2 mol % of initiator is metered in over 2.5 hours. After a continued reaction period of 30 minutes, the acetylene feed is stopped and acetylene is driven out of the apparatus with nitrogen. After the reaction mixture has been cooled, the solid formed is filtered off with suction and redispersed with 75 g of acetone, washed and dried in a vacuum drying cabinet at 100° C. for 4 hours. In a yield of 65%, 34.9 g of a mixture of ethylene-1,2-bis(ethylphosphinic acid) (98% by weight) and diethylphosphinic acid (2% by weight) are obtained.

EXAMPLE 4

[0115] 0.5 mol of ethylphosphinic acid (prepared according to example 1) is initially charged in n-butanol as a solvent and inertized with a nitrogen gas stream while stirring for 30 minutes and heated to 90° C. Acetylene is passed through the reaction solution at 30 l/h, and 0.2 mol % of initiator is metered in over 2 hours. After a continued reaction period of 30 minutes, the acetylene feed is stopped and acetylene is driven out of the apparatus with nitrogen. After the reaction mixture has been cooled, the solid formed is filtered off with suction and redispersed with 75 g of acetone, washed and dried in a vacuum drying cabinet at 100° C. for 4 hours.

[0116] In a yield of 63%, 34.2 g of a mixture of ethylene-1,2-bis(ethylphosphinic acid) (90% by weight) and diethylphosphinic acid (10% by weight) are obtained.

EXAMPLE 5

[0117] 21.5 g of pure diethylphosphinic acid are added to the mixture of ethylene-1,2-bis(ethylphosphinic acid) (99.9% by weight) and diethylphosphinic acid (0.1% by weight) synthesized according to example 2, so as to obtain a mixture of 60% by weight of ethylene-1,2-bis(ethylphosphinic acid) and 40% by weight of diethylphosphinic acid. The aforementioned diethylphosphinic acid is prepared according to example 8 of EP-B-1544205, in which distillation is effected according to the “Addition of sulfuric acid” step therein, in order to obtain the pure diethylphosphinic acid, and there is thus no conversion to a salt of diethylphosphinic acid.

EXAMPLE 6

[0118] 34.8 g of pure diethylphosphinic acid are added to the mixture of ethylene-1,2-bis(ethylphosphinic acid) (99.9% by weight) and diethylphosphinic acid (0.1% by weight) synthesized according to example 2, so as to obtain a mixture of 50% by weight of ethylene-1,2-bis(ethylphosphinic acid) and 50% by weight of diethylphosphinic acid. The aforementioned diethylphosphinic acid is prepared according to example 8 of EP-B-1544205, in which distillation follows the “Addition of sulfuric acid” step therein, in order to obtain the pure diethylphosphinic acid, and there is thus no conversion to a salt of diethylphosphinic acid.

[0119] Method for Producing Polymer Moldings:

[0120] Production of Epoxy Resin Specimens

[0121] 100 parts of the phosphorus-modified epoxy resin are mixed with a corresponding OH equivalent of phenol resin and heated to 150° C. This liquefies the components. The mixture is stirred gradually until a homogeneous mixture has formed and is allowed to cool to 130° C. Then 0.03 part 2-phenylimidazole is added and the mixture is stirred once again for 5-10 min. Thereafter, the mixture is poured warm into a dish and cured at 140° C. for 2 h and at 200° C. for 2 h.

[0122] Production of Epoxy Resin Laminate

[0123] 100 parts phosphorus-modified epoxy resin are added to 63 parts acetone and 27 parts Dowanol PM, and the appropriate amount of phenol resin is added. The mixture is left to stir for 30 min and then 2-phenylimidazole is added. The amount of phenylimidazole should be chosen such that the gel time is 240 sec. Thereafter, the target viscosity (flow cup) should be established by further addition of solvent. Thereafter, the mixture is filtered through a 400 μm sieve in order to remove excess resin particles. Then the woven glass fabric (7628 type, 203 g/m.sup.2) is immersed into the solution until complete wetting of the fabric has taken place. The sample is cautiously pulled out of the mixture and excess resin is removed. Thereafter, the sample is cured stepwise in a drying cabinet at temperatures up to 165° C. for a short period, such that the solvent has been removed and the prepreg has been precrosslinked. The gel time of these prepregs should be checked. Eight prepregs are laminated and cured in a heated press. The resin content of the cured laminates is 30-50%.

[0124] The thermal expansion of the molding produced, a laminate, is determined to ASTM E831-06.

EXAMPLE 7 (COMPARATIVE)

[0125] According to the general method for producing a polymer molding, 100% of a bisphenol A resin is used to produce a laminate.

EXAMPLE 8

[0126] Pure ethylene-1,2-bis(ethylphosphinic acid) is obtained according to example 2 with subsequent washing of the product with organic solvents.

[0127] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of ethylene-1,2-bis(ethylphosphinic acid) is used to produce a molding.

EXAMPLE 9

[0128] First of all, diethylphosphinic acid is prepared according to example 8 of EP-B-1544205, in which the addition of the sulfuric acid is followed by distillation in order to obtain a pure diethylphosphinic acid.

[0129] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of diethylphosphinic acid is used to produce a molding.

EXAMPLE 10

[0130] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid according to example 2 is used to produce a molding.

EXAMPLE 11

[0131] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid according to example 3 is used to produce a molding.

EXAMPLE 12

[0132] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid according to example 4 is used to produce a molding.

EXAMPLE 13

[0133] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid according to example 5 is used to produce a molding.

EXAMPLE 14

[0134] According to the general method for producing a polymer molding, a composition composed of 90% by weight of bisphenol A resin with hardener and catalyst and 10% by weight of the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid according to example 6 is used to produce a molding.

TABLE-US-00002 TABLE Compositions of the polymer mixture and of the mixtures used, and test results Composition Mixture of of ethylene-1,2-bis- polymer (ethylphosphinic acid)/ Coefficient of system/ diethylphosphinic thermal expansion mixture acid 0°-100° [ppm/° C.] Example [% by weight] [% by weight] Z X Y 7 100:0  69 20 7 8 90:10 100:0  68 20 7 9 90:10  0:100 70 22 7 10 90:10 99.9:0.1  65 18 5 11 90:10 98:2  62 16 5 12 90:10 90:10 60 16 5 13 90:10 60:40 57 13 4 14 90:10 50:50 56 13 4

[0135] Compared to the pure laminate (example 7), there is a decrease in the values for the laminate comprising the inventive mixture of ethylene-1,2-bis(ethylphosphinic acid) and diethylphosphinic acid; thermal expansion is thus very low. An increase in the diethylphosphinic acid content brings about a further improvement.

[0136] Compared to the prior art (example 7), the inventive mixtures exhibit lower values for the coefficient of thermal expansion, meaning that the inventive products lead to lower expansion of the moldings produced and hence meet the demands on dimensional stability.

EXAMPLE 15

[0137] Production of Polyester-Based Polymer Moldings:

[0138] a) Preparation of Phosphorus-Modified Polyethylene Terephthalate

[0139] 1000 g of dimethyl terephthalate are transesterified with 720 ml of ethylene glycol and 230 mg of Mn(OCOCH.sub.3).sub.4*4H.sub.2O at temperatures of 170-220° C. under a nitrogen atmosphere. After the methanol has been separated out, 17.2 g of the inventive mixture from example 4 are added at 220° C. and, after addition of 350 mg of Sb.sub.2O.sub.3, the reaction vessel is heated further to 250° C. and a vacuum is applied simultaneously. The polymerization is effected at 0.2 mm Hg and 287° C. within 2 hours. The resulting product has a melting point of 240-244° C. and a phosphorus content of 0.5%, and is in the form of pellets.

[0140] b) Production of Polymer Moldings

[0141] The polymer pellets thus produced are mixed with any additives and they are incorporated in a twin-screw extruder (model: Leistritz LSM 30/34) at temperatures of 250 to 290° C. (PET-GR). The homogenized polymer strand was drawn off, cooled in a water bath and then pelletized.

[0142] After sufficient drying, the molding compositions were processed on an injection molding machine (model: Aarburg Allrounder) at melt temperatures of 250 to 300° C. (PET-GR) to give test specimens.

[0143] The UL 94 fire class and the LOI were determined on test specimens of thickness 1.6 mm. Moldings of thickness 1.6 mm result in V-0 and an LOI of 28%.