FLAME RETARDED POLYESTER BLEND

Abstract

Thermoplastic molding compositions comprising a thermoplastic polyester, a poly(ε-caprolactone), a biodegradable polyester differing from the poly(ε-caprolactone), a phosphinic salt and a polar modified polyolefin wax prepared by means of metallocene catalysts, the use of the thermoplastic molding compositions for the production of flame-retardant moldings of any type, to the resultant moldings, and to the use of the polar modified polyolefin wax prepared by means of metallocene catalysts for an improvement of the flame retardancy of thermoplastic molding compositions comprising a thermoplastic polyester.

Claims

1. A thermoplastic molding composition comprising A) from 10 to 99.6% by weight of a thermoplastic polyester differing from C); B) from 0.1 to 30% by weight of a poly(ε-caprolactone); C) from 0.1 to 30% by weight of a biodegradable polyester differing from B); D) from 0.1 to 30% by weight of a phosphinic salt; E) from 0 to 20% by weight of a nitrogen-containing flame retardant; F) from 0 to 15% by weight of an aromatic phosphate ester having at least one alkyl-substituted phenyl ring; G) from 0.05 to 1% by weight of a polyolefin wax prepared from a metallocene catalyst, where the polyolefin wax is a homopolymer of ethylene, a copolymer of ethylene with one or more 1-olefins which may be linear or branched, substituted or unsubstituted and having 3-18 carbon atoms or a homopolymer of propylene, which is polar modified by reacting the polyolefin wax with an α,β-unsaturated carboxylic acid or a derivative thereof; H) from 0 to 50% by weight of further additional substances, where the sum of the percentages by weight of components A) to H) is 100%.

2. The thermoplastic molding composition according to claim 1, wherein component G) is a homopolymer of ethylene or a copolymer of ethylene with one or more 1-olefins which may be linear or branched, substituted or unsubstituted and having 3 to 18 carbon atoms, which is polar modified by reacting the polyolefin wax with maleic anhydride.

3. The thermoplastic molding composition according to claim 1, wherein the thermoplastic polyester A) is based on an aromatic dicarboxylic acid and on an aliphatic and/or aromatic dihydroxy compound.

4. The thermoplastic molding composition according to claim 1, wherein component C) comprises C1) from 30 to 70 mol %, based on C1) and C2), of an aliphatic dicarboxylic acid or mixture thereof, C2) from 30 to 70 mol %, based on C1) and C2), of an aromatic dicarboxylic acid or mixture thereof, C3) from 98.5 to 100 mol %, based on C1) and C2), of 1,4-butanediol or 1,3-propanediol or a mixture of these, C4) from 0.05 to 1.5% by weight, based on C1) to C3), of a chain extender.

5. The thermoplastic molding composition according to claim 1, wherein component D) is a phosphinic salt of the formula (I) or/and a diphosphinic salt of the formula (II) or of polymers of these ##STR00021## wherein R.sup.1 and R.sup.2, being identical or different, are hydrogen or, in linear or branched form, C.sub.1-C.sub.6-alkyl, and/or aryl, or ##STR00022## wherein R′ is hydrogen, phenyl or tolyl; R.sup.3 is, in linear or branched form, C.sub.1-C.sub.10-alkylene or C.sub.6-C.sub.10-arylene, C.sub.1-C.sub.10-alkyl-C.sub.6-C.sub.10arylene or C.sub.6-C.sub.10-aryl C.sub.1-C.sub.10alkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and/or a protonated nitrogen base; m is from 1 to 4; n is from 1 to 4; x is from 1 to 4.

6. The thermoplastic molding composition according to claim 5, wherein R.sup.1 and R.sup.2 of component D) are mutually independently hydrogen, methyl or ethyl.

7. The thermoplastic molding composition according to claim 1, wherein component E) is a reaction product of melamine (formula I) and cyanuric acid or isocyanuric acid (formulae Ia and Ib) ##STR00023##

8. The thermoplastic molding composition according to claim 1, wherein the melting point of component F), measured by means of DSC in accordance with ISO 11357, 1st heating curve at 20 K/minute, is from 50 to 150° C.

9. The thermoplastic molding composition according to claim 1, wherein component F) is ##STR00024## or a mixture of these, where, mutually independently, R.sup.1 is H, methyl or isopropyl n is from 0 to 7 R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each independently represents H, methyl, ethyl or isopropyl m is from 1 to 5 R″ is H, methyl, ethyl or cyclopropyl, with the proviso that at least one moiety R.sup.2, R.sup.3, R.sup.4, R.sup.5 or R.sup.6 is an alkyl moiety.

10. The thermoplastic molding composition according to claim 9, wherein the substituents of the general formula III, IV and V are: R.sup.1 hydrogen and/or R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 methyl and/or m is 1 or 2.

11. The thermoplastic molding composition according to claim 10, in which component F) is ##STR00025##

12. A method for the production of fibers, films and moldings comprising forming a polyester molding composition according to claim 1.

13. A fiber, film, or molding obtained from the polyester molding composition according to claim 1.

14. A method for improving the flame retardancy of a thermoplastic molding composition comprising a thermoplastic polyester by adding a polyolefin wax prepared by means of metallocene catalysts, where the polyolefin wax is a homopolymer of ethylene, a copolymer of ethylene with one or more 1-olefins which may be linear or branched, substituted or unsubstituted and having 3 to 18 carbon atoms or a homopolymer of propylene, which is polar modified by reacting the polyolefin wax with an α,β-unsaturated carboxylic acid or a derivative thereof to the thermoplastic polyester.

15. The method according to claim 14, wherein the thermoplastic molding composition is thin-walled parts with a wall thickness of at most 0.4 mm.

16. The thermoplastic molding composition according to claim 3 wherein the thermoplastic polyester A) is selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate or mixtures of these, wherein polyethylene terephthalate and/or polybutylene terephthalate may comprise up to 1% by weight of 1,6-hexanediol and/or 2-methyl-1,5-pentanediol as further monomer units.

17. The thermoplastic molding composition according to claim 4 wherein component c) is polybutylene adipate terephthalate (PBAT) or polybutylene sebacate terephthalate (PBSeT)

Description

EXAMPLES

[0280] Components of the molding compositions/production of the molding compositions/test specimen

[0281] Component A:

[0282] Polybutylene terephthalate with intrinsic viscosity IV 130 ml/g and carboxy end group content 34 meq/kg (Ultradur® B 4520 from BASF SE) (IV measured in 0.5% by weight solution of phenol/o-dichlorobenzene, 1:1 mixture, at 25° C. in accordance with DIN 53728 and ISO 1628).

[0283] Component B:

[0284] Poly-(ε)-caprolactone (Capa® 6500 from Ingevity Corp.): M.sub.w (GPC, hexafluoroisopropanol/0.05% of potassium trifluoroacetate, PMMA standard): 99 300 g/mol with intrinsic viscosity IV 226 ml/g (IV measured in 0.5% by weight solution of phenol/o-dichlorobenzene, 1:1 mixture, at 25° C. in accordance with DIN 53728 and ISO 1628). Melting range (DSC, 20 K/min in accordance with DIN 11357): from 58 to 60° C.

[0285] Component C:

[0286] Copolyester: polybutylene adipate-co-terephthalate, melting point (DSC, 20 K/min in accordance with DIN 11357): from 100 to 120° C. Ecoflex® F. blend C1200 from BASF SE.

[0287] Component D/1:

[0288] Al diethylphosphinate (Exolit® OP 1230 from Clariant GmbH).

[0289] Component F/1:

[0290] Aromatic phosphate ester. Melting range (DSC, 20 K/min in accordance with DIN 11357): from 92 to 100° C. PX-200 from Daihachi Chemical Industry Co.

##STR00019##

[0291] Component F/2:

[0292] Aromatic phosphate ester. Melting range (DSC, 20 K/min in accordance with DIN 11357): from 102 to 110° C. Fyrolflex® SOL-DP from ICL-IP Europe.

##STR00020##

[0293] Component H/1:

[0294] PTFE powder. Dyneon TF2071 PPFE from 3M from Dyneon GmbH. The TDS particle size is 500 μm (ISO 12086) and density is 2.16 g/cm.sup.3 (ISO 12086).

[0295] Component G:

[0296] Maleic anhydride grafted metallocene polyethylene wax. Licocene® PE MA 4221 fine grain from Clariant GmbH.

[0297] Component H/2:

[0298] Stabilizer. Irgafos® 168 from BASF SE.

[0299] Production of the Molding Compositions

[0300] The molding compositions for the inventive and comparative examples in Table 1 were produced by means of a ZE25 twin-screw extruder. The temperature profile was kept constant, increasing from 240° C. in zone 1 to 260° C. (zones 2 to 9). Rotation rate was set at 130 rpm, resulting in throughput of about 7.5 to 9.6 kg/h, depending on formulation. The extrudate was drawn through a water bath and pelletized. The pellets were then processed by injection molding.

[0301] Testing of Properties

[0302] The test specimens for the tests listed in table 1 were injection-molded in an Arburg 420C injection molding machine at a melt temperature of about 270° C. and at a mold temperature of about 80° C. The test specimens for the stress tests were produced in accordance with ISO 527-2:/1993, and the test specimens for the impact resistance tests were produced in accordance with ISO 179-2/1 eA.

[0303] The MVR tests were carried out in accordance with ISO1133.

[0304] The flame retardancy of the molding compositions was determined firstly by the UL 94 V method (Underwriters Laboratories Inc. Standard of Safety, “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, p. 14 to p. 18, Northbrook 1998).

[0305] Glow—wire resistance GWFI (glow—wire flammability index) was tested in accordance with DIN EN 60695-2-12 on plaques. The GWFI test is a general suitability test for plastics in contact with parts that carry an electrical potential. The temperature determined is the highest at which one of the following conditions is met in three successive tests: (a) no ignition of the specimen or (b) afterflame time or afterglow time 30 s after end of exposure to the glow wire, and no ignition of the underlay.

[0306] The sum of the contents of components A) to H) in Table 1 (comparative examples=V1 to V4, inventive example=E1) add to 100% by weight. The compositions of the moldings and the results of the measurements are summarized in Table 1:

TABLE-US-00003 TABLE 1 Components (wt %)/ Testing method V1 V2 V3 V4 E1 A 69.3 68.3 67.3 66.3 69.3 B 4 4 4 4 4 C 4 4 4 4 4 D/1 20 21 22 23 20 F/1 1 1 1 1 1 F/2 1 1 1 1 1 H/1 0.4 0.4 0.4 0.4 0.4 G — — — — 0.1 H/2 0.3 0.3 0.3 0.3 0.3 VZ.sup.1)/[mL/g] 125 126 125 125 126 MVR.sup.2) 275/2.16/ 31.9 30.9 28.8 28.9 33.0 [ccm/10 min] Tensile modulus of 2069 2079 2094 2100 2082 elasticity/[MPa] Tensile strength at 27.9 27.3 26.8 26.0 28.0 break/[MPa] Tensile strain at break/[%] 22.5 20.1 19.5 18.1 21.2 Charpy unnotched/KJ/m.sup.2 38 34 35 32 34 Charpy unnotched at 32 33 31 28 32 −30° C./KJ/m.sup.2 Charpy notched/KJ/m.sup.2 3.2 2.9 3.0 2.7 3.2 UL94 (0.4 mm) V-2 V-2 V-2 V-2 V-0 UL94 (0.8 mm) V-0 V-0 V-0 V-0 V-0 GWFI 960° C./0.75 mm passed passed passed passed passed GWIT 775° C./0.75 mm passed passed passed passed passed GWFI 960° C./1.5 mm passed passed passed passed passed Deposits at nozzle during heavy heavy heavy heavy none pipe extrusion .sup.1)Viscosity number in accordance with ISO307 .sup.2)Melt viscosity rate in accordance with ISO1133

[0307] It is clear from the data in Table 1 that the inventive polyester molding composition El shows an improved fire behavior especially at thin-walled parts (UL94-test at 0.4 mm). The amount of component G used has a higher impact on the UL94 fire behavior than the increase of the flame retardant D/1 (V2 to V4). Further, the inventive molding composition shows a significantly improved processing behavior in extrusion applications (no deposits at the nozzle).