Flame-Retardant Polyester Molding Compositions

Abstract

The present invention relates to a thermoplastic molding composition comprising a thermoplastic polyester, a metal salt of formula (I), a halogen-containing flame retardant, and an anti-dripping agent; a method of producing fibers, foils and moldings comprising the use of the thermoplastic molding composition; and a fiber, foil or molding obtained from the thermoplastic molding composition.

##STR00001##

Claims

1. A thermoplastic molding composition comprising A) from 10 to 98% by weight of a thermoplastic polyester B) from 0.5 to 20% by weight of a metal salt of the following formula (I): ##STR00016## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.5 and R.sup.6 are each independently hydrogen or C.sub.1-C.sub.4 alkyl; x is 1, 2, 3 or 4; Met is a metal respectively metalloid of the 1.sup.st, 2.sup.nd, 13.sup.th, 14.sup.th or 15.sup.th group of the periodic table of elements (IUPAC), a transition metal of the 3.sup.rd to 12.sup.th group of the periodic table of elements (IUPAC), a lanthanoid metal or an oxy derivative of one of the metals, metalloids or transition metals mentioned; C) from 1.5 to 30% by weight of a flame retardant combination made of C.sub.1) a halogen-containing flame retardant and C.sub.2) an antidripping agent D) from 0 to 50% by weight of other additives, where the total of the percentages by weight of components A) to D) is 100%.

2. The thermoplastic molding composition according to claim 1, wherein the thermoplastic molding composition is free of diantimony trioxide (Sb.sub.2O.sub.3).

3. The thermoplastic molding composition according to claim 1, wherein Met in the metal salt B) is a metal respectively metalloid of the 13.sup.th, 14.sup.th or 15.sup.th group of the periodic table of elements (IUPAC), a transition metal of the 3.sup.rd to 12.sup.th group of the periodic table of elements (IUPAC), a lanthanoid metal or an oxy derivative of one of the metals, metalloids, or transition metals mentioned.

4. The thermoplastic molding composition according to claim 1, wherein Met is selected from the group consisting of Al, Ge, Sn, Bi, Ti, V, Cr, Mn, Fe, La, Ce, OTi, OV, OCr, OSn and OBi.

5. The thermoplastic molding composition according to claim 1, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are hydrogen.

6. The thermoplastic molding composition according to claim 1, wherein the thermoplastic polyester A) is a semi-crystalline or amorphous polyester, based on dicarboxylic acids and diols, having a viscosity number of 50 to 180 mL/g, determined in a 0.5% by weight solution in phenol/o-dichlorobenzene (1:1) at 25° C. according to DIN 53728/ISO 307.

7. The thermoplastic molding composition according to claim 6, wherein the dicarboxylic acids are aliphatic or aromatic dicarboxylic acids having 4 to 18 carbon atoms.

8. The thermoplastic molding composition according to claim 6, wherein the diols are selected from the group consisting of cycloaliphatic diols having 6 to 20 carbon atoms and aliphatic diols having 2 to 20 carbon atoms and-poly(alkylene oxide) glycols containing a total of 3 to 12 carbon atoms including up to 3 or 4 oxygen atoms with the remaining atoms being hydrocarbon atoms.

9. The thermoplastic molding composition according to claim 1, wherein component C) comprises from 95 to 99.95% by weight of C.sub.1) and from 0.05 to 5% by weight of C.sub.2).

10. The thermoplastic molding composition according to claim 1, wherein the antidripping agent C.sub.2) is a compound selected from the group consisting of fluorine-containing polymers, siloxane based antidripping agents, and mixtures thereof.

11. The thermoplastic molding composition according to claim 10, wherein the fluorine-containing polymers are selected from the group consisting of poly(tetrafluoroethylene), tetrafluoroethylene/hexafluoropropylene copolymers, tetrafluoroethylene/ethylene copolymers, poly(vinylidene fluoride), poly(chlorotrifluoroethylene), and mixtures thereof and the siloxane based antidripping agent comprises polydimethylsiloxane.

12. The thermoplastic molding composition according to claim 1, wherein component C.sub.1) is a bromine or chlorine containing flame retardant.

13. The thermoplastic molding composition according to claim 12, wherein the bromine containing flame retardant is selected from the group consisting of brominated diphenyl ether, brominated trimethylphenylindane, tetrabromobisphenol A, hexabromocyclododecan, and brominated oligocarbonates of tetrabromobisphenol A having the following formula, wherein n is more than 2: ##STR00017## polypentabrombenzylacrylate of the following formula, wherein n is more than 4: ##STR00018## oligomeric reaction products of tetrabromobisphenol A with epoxides of the following formula, wherein n is more than 3: ##STR00019## brominated oligostyrenes having a mean degree of polymerization (number average) between 3 and 90, as measured by vapor pressure osmometry in toluene, brominated polystyrenes; and mixtures of the brominated oligomeric styrenes and brominated polystyrenes, in any mixing ratio.

14. A method of producing fibers, foils, and moldings comprising molding a thermoplastic molding composition according to claim 1.

15. A fiber, foil, or molding obtained from a thermoplastic molding composition according to claim 1.

16. The method according to claim 12 wherein the chlorine containing flame retardant is declorane plus of the following formula: ##STR00020##

17. The thermoplastic molding composition of claim 6 wherein the dicarboxylic acids are selected from the group consisting of phthalic acid, terephthalic acid, dimethyl terephthalic acid, isophthalic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4′-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid and sebacic acid and mixtures thereof.

18. The thermoplastic molding composition of claim 6 wherein the diols are selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexane dimethanol, propane-1,3-diol, propane-1,2-diol, butane-1,2-diol, butane-1,4-diol, pentane-1,5-diol, hexane1,6-diol, 3-methylpentane-2,4-diol, 2-methylpentane-1,4-diol, 2,2,4-trimethylpentane-1,3-diol, hexane-1,3-diol, hexane-1,4-diol, 2,2-bis(4-hydroxycyclohexyl)propane and 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane isosorbitol, poly(oxyethylene)diol, poly(oxypropylene)diol, or poly(oxytetramethylene)diol, and mixtures thereof.

19. The fiber, foil, or molding of claim 15 wherein the molding is an injection molded electronic component.

Description

EXAMPLES

Production of the Molding Compositions/Test Specimen

[0104] The molding compositions were manufactured by melt compounding. For this, the individual components were mixed in a twin-screw extruder ZSK 26 (Berstorft) with a turnover rate of 20 kg/h and about 250 to 270° C. with a flat temperature profile, extruded in the form of strands, cooled until pelletizable and pelletized.

[0105] The test specimens for the tests mentioned in the following table were injection-molded at a melt temperature of about 250 to 290° C. and a mold temperature of about 80° C. in an Arburg 420C injection molding machine.

[0106] The flame retardancy of the molding material was determined by method UL94-V (Underwriters Laboratories Inc. Standard of Safety, “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, pages 14 to 18, Northbrook 1998).

[0107] The glow-wire resistance was determined by determining the Glow-Wire Flammability Index (GWFI) according to IEC 60695-2-12.

[0108] GWFI was determined by conducting the glow-wire test on three test specimens (for example on test plates having a geometry 60×60×1.0 mm or a round disc). By aids of a glowing wire at temperatures between 550 and 960° C., the highest temperature was determined, at which the material in three subsequent tests did not ignite during the contact time of the glowing wire. The test specimen was pressed for 30 seconds with a power of 1 Newton against a heated glowing wire. The penetration of the glowing wire was limited to 7 mm. The test is passed when the test specimen afterglows for less than 30 seconds after removal of the glowing wire and when a tissue paper lying under the test specimen is not ignited.

[0109] The glow-wire resistance was further determined by measuring the Glow-Wire Ignition Temperature (GWIT) according to DIN EN 60695-2-13. In the GWIT test, the maximum temperature was determined, at which in three subsequent tests also during the contact time of the glowing wire, no ignition occurred. The GWIT test was conducted at three test specimens (for example plates having a geometry 60×60×1.5 mm) by aid of a glowing wire at temperatures between 550 and 960° C. The GWIT specified was 25K above the maximum temperature determined. As criterion of the ignition, a flame with a burning time >5 seconds is applied.

[0110] The resistance to exposure of voltage (Comparative Tracking Index=CTI value) was determined according to the determination of the resistance to exposure of voltage according to IEC 60112.

[0111] In the examples, the following components have been used:

Component A:

[0112] Ultradur® B4520 of BASF SE (PBT having a viscosity number according to DIN 53728 of 130 cm.sup.3/g).

Component B1:

[0113] An aluminum salt of the (commercially available) DOPO acid (10-hydroxy-9,10-dihydro-9-oxa-10-phosphophenantrenoxide=DOPDX) was prepared by following instructions: In a glass bulb 355.2 g (8.610 mol) of NaOH were dissolved in 1 l deionized water in portion under stirring. This solution was thereby cooled. In the meantime, in a 20 l beaker 2000 g (8.610 mol) DOPDX were suspended in 10 l deionized water. The NaOH solution prepared was then added to the DOPDX suspension in portion during 60 min under stirring, and rinsed with deionized water. Thereby, a brown-black solution was formed which is stirred until the complete solids were dissolved. Subsequently, 693.4 g (2.870 mol) aluminum chloride hexahydrate were dispersed in 2.5 l deionized water in portion, and subsequently added to the reaction mixture in portion during 60 min, whereby the end product precipitated as a solid. The reaction mixture was stirred for 2 h at room temperature, and after 24 h, the solid is filtered and suspended in 12 l of deionized water under vigorous stirring. The solids were subsequently filtered and again rinsed with deionized water and dried in vacuum at 130° C.

Component B2:

[0114] An iron(III) salt of the (commercially available) DOPO acid (10-hydroxy-9,10-dihydro-9-oxa-10-phosphophenantrenoxide=DOPDX) was prepared by following instructions:

[0115] On the previous day, 177.6 g (4.31 mol) of NaOH in 0.5 l deionized water were solved in portion under stirring. This solution was thereby cooled. The reaction vessel is stored closed until use. In a 20 l beaker 1000 g (4.31 mol) DOPDX were suspended in 5 l deionized water. The NaOH solution prepared was added to the DOPDX suspension in portion during 60 min under stirring and rinsed with deionized water. Thereby, a brown-black solution was formed which was stirred until the complete solids were dissolved. In the meantime, 386.39 g (1.43 mol) iron chloride hexahydrate were dispersed in 1 l deionized water in portion, and subsequently added to the reaction mixture in portion during 60 min, and rinsed with deionized water. A solid precipitated immediately. The reaction mixture was stirred for 2 h at room temperature, and stands overnight, for sedimentation of the solids. The solids were filtered and vigorously stirred in 6 l of deionized water for 1 h. The solids were filtered and rinsed with deionized water. Subsequently, the solids were dried in vacuum first at 80° C. and later at 130° C. in vacuum.

Component C1/a:

[0116] Brominated flame retardant based on tetrabromobisphenol A (BC-52™ of Lanxess).

Component C2:

[0117] Commercially available PTFE powder is used (3M-Dyneon GmbH).

Component C3:

[0118] Commercially available calcium hypophosphite is used (Phoslite IP-C® of Italmatch Chemicals S.P.A.).

Component D:

[0119] A short glass fiber PPG 3786 (PPG Industries, Inc.) having a diameter of 10 μm is used.

TABLE-US-00001 TABLE 1 V1 E1 (comparative (inventive Component/test method example) example) A 39.75 39.75 B1 10 B2 C1/a 20 20 C1/b C1/c C2 0.25 0.25 C3 10 D 30 30 Tensile modulus of elasticity [MPa] 12330 11370 (ISO 527) Tensile stress [MPa] (ISO 527) 128 104 Elongation at break [%] (ISO 527) 1.7 1.4 HDT (heat deflection temperature) A 192 191 [° C.] MVR (Melt Volume-flow Rate) 6 10 275° C./5 kg (ISO1133) UL94-V test (0.8 mm) V-2 V-0 UL94-V test (0.4 mm) V-2 V-0 GWFI 960° C./0.75 mm fulfilled fulfilled GWIT max/0.75 mm [° C.] 850 850 GWFI 960° C./1.5 mm fulfilled fulfilled GWIT max/1.5 mm [° C.] 850 900 CTI [V] 175 175

[0120] It is clear from the data shown in Table 1 that the inventive composition shows superior values concerning the fire behavior according to UL94-V (V-0 classification) compared with the prior art (comparative example V1 in the self-extinguishing properties (no flaming droplets).