GLASS FIBER FILLED FLAME RETARDANT PROPYLENE COMPOSITION

Abstract

The invention relates to a glass fiber filled flame retardant polypropylene composition comprising (A) a polypropylene-based polymer, (B) a first flame retardant in an amount of 15 to 40 wt % of the total composition, wherein the first flame retardant is in the form of particles comprising ammonium polyphosphate and at least one phosphate selected from the group consisting of melamine phosphate, melamine polyphosphate, melamine pyrophosphate, piperazine phosphate, piperazine polyphosphate, piperazine pyrophosphate, 2-methylpiperazine monophosphate, tricresyl phosphate, alkyl phosphates, haloalkyl phosphates, tetraphenyl pyrophosphate, poly(2-hydroxy propylene spirocyclic pentaerythritol bisphosphate) and poly(2,2-dimethylpropylene spirocyclic pentaerythritol bishosphonate), (C) a second flame retardant in an amount of 0.1 to 15 wt % of the total composition, wherein the second flame retardant comprises an aromatic phosphate ester and (D) glass fibers in an amount of 5 to 40 wt % of the total composition.

Claims

1. A glass fiber filled flame retardant polypropylene composition comprising (A) a propylene-based polymer, (B) a first flame retardant in an amount of 15 to 40 wt % of the total composition, wherein the first flame retardant is in the form of particles comprising ammonium polyphosphate and at least one phosphate selected from the group consisting of melamine phosphate, melamine polyphosphate, melamine pyrophosphate, piperazine phosphate, piperazine polyphosphate, piperazine pyrophosphate, 2-methylpiperazine monophosphate, tricresyl phosphate, alkyl phosphates, haloalkyl phosphates, tetraphenyl pyrophosphate, poly(2-hydroxy propylene spirocyclic pentaerythritol bisphosphate) and poly(2,2-dimethylpropylene spirocyclic pentaerythritol bisphosphonate) and (C) a second flame retardant in an amount of 0.1 to 15 wt % of the total composition, wherein the second flame retardant comprises an aromatic phosphate ester and (D) glass fibers in an amount of 5 to 40 wt % of the total composition.

2. The composition according to claim 1, wherein the polypropylene-based polymer comprises a propylene homopolymer or a propylene-α-olefin copolymer consisting of at least 70 wt % of propylene and up to 30 wt % of α-olefin based on the total weight of the copolymer, wherein the α-olefin is selected from the group of α-olefins having 2 or 4-10 carbon atoms.

3. The composition according to claim 1, wherein the polypropylene-based polymer comprises a heterophasic propylene copolymer consisting of (a) a propylene-based matrix, wherein the propylene-based matrix consists of a propylene homopolymer and/or a propylene copolymer consisting of at least 70 wt % of propylene monomer units and at most 30 wt % of ethylene and/or α-olefin monomer units, based on the total weight of the propylene-based matrix and wherein the propylene-based matrix is present in an amount of 60 to 95 wt % based on the total heterophasic propylene copolymer and (b) a dispersed ethylene-α-olefin copolymer, wherein the dispersed ethylene-α-olefin copolymer is present in an amount of 40 to 5 wt % based on the total heterophasic propylene copolymer and wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene-α-olefin copolymer in the heterophasic propylene copolymer is 100 wt %.

4. The composition of claim 1, wherein the first flame retardant has a normal particle size distribution (D50) of at least 8 microns as determined by Mastersizer 2000 available from Malvern.

5. The composition of claim 1, wherein the amount of phosphate in the first flame retardant is 40-75 wt % as measured after treating with nitric acid using ICP-OES spectrometer (iCAP 6300 Duo available from Thermo Fisher).

6. The composition of claim 1, wherein the first flame retardant comprises melamine phosphate.

7. The composition of claim 1, the first flame retardant further comprises zinc oxide.

8. The composition of claim 1, wherein the amount of the ammonium polyphosphate in the first flame retardant is 5-15 wt %.

9. The composition of claim 1, wherein the amount of the ammonium polyphosphate in the first flame retardant is 5-15 wt %, the amount of melamine phosphate in the first flame retardant is 50-80 wt %, the amount of piperazine phosphate in the first flame retardant is 10-25 wt % and the amount of zinc oxide in the first flame retardant is 1-10 wt %.

10. The composition of claim 1, wherein the aromatic phosphate ester is selected from the group consisting of resorcinol bis(diphenyl phosphate); tetraphenyl resorcinol bis(diphenylphosphate); bisphenol A bis(diphenyl phosphate); bisphenol A diphosphate; resorcinol bis(di-2,6-xylyl phosphate), phosphoric acid, mixed esters with [1,1′-biphenyl]-4-4′-diol and phenol; phosphorictrichloride, polymer with 1,3-benzenediol, phenylester; 1,3-phenylene-tetrakis(2,6-dimethylphenyl)diphosphate; isopropenylphenyl diphenyl phosphate; 4-phenylphenolformaldehyde phenylphosphonate; tris(2,6-xylyl) phosphate; Resorcinol bis(di-2,6-xylyl phosphate); bisphenol S bis(diphenyl phosphate); and resorcinol-bisphenol A phenyl phosphates.

11. The composition of claim 1, wherein the amount of (A) is 50 to 90 wt %, with respect to the total composition.

12. The composition of claim 1, wherein the total amount of (A), (B), (C) and (D) is at least 90 wt % of the total composition.

13. The composition of claim 1, wherein the composition has a notched Charpy impact strength according to ISO 179-1:2010 at 23° C. (test geometry: 80*10*4 mm) of at least 4.0 kJ/m.sup.2.

14. A process for the preparation of the composition according to claim 1, comprising melt mixing (A), (B), (C) and (D) and optional components.

15. An article comprising the composition of claim 1.

16. The article of claim 15, wherein the article is selected from the group consisting of enclosures of (miniature) circuit breakers, battery carriers and covers in electric cars, caps and closures, batteries, pails, containers, external and internal parts in appliances, like printed circuit board holder, circuit breaker cover, drain pan in refrigerator, deflection coil of TV, stadium seats, automotive exterior parts like bumpers, automotive interior parts like instrument panels, and automotive parts under the bonnet.

Description

EXAMPLES

[0186] Materials as shown in Table 1 were used in the experiments.

TABLE-US-00001 TABLE 1 Description Polypropylene 1 PP Homopolymer, MFI 47 g/10 min Polypropylene 2 heterophasic propylene copolymer comprising a matrix phase of a propylene homopolymer and a dispersed phase of propylene-ethylene copolymer having MFI of 30 g/10 min, Dispersed phase (RC): 19.1 wt %, Ethylene in dispersed phase (RCC2): 47.2 wt %, Ethylene in heterophasic propylene copolymer (T2): 9 wt % Polypropylene 3 heterophasic propylene copolymer comprising a matrix phase of a propylene homopolymer and a dispersed phase of propylene-ethylene copolymer having MFI of 22 g/10 min, Dispersed phase (RC): 21.1 wt %, Ethylene in dispersed phase (RCC2): 52.1 wt %, Ethylene in heterophasic propylene copolymer (T2): 17.5 wt % Glass fiber 1 Glass fibers with average diameter of 13 μm and average length of 4.5 mm Glass fiber 2 Glass fibers with average diameter 13 μm and average length of 3 mm Adhesion promoter polypropylene grafted with maleic anhydride (Exxelor ® PO1020) Flame retardant 1 10-15% Ammonium polyphosphate, 60-70% Melamine phosphate, 15-20% phosphoric acid compound (not melamine phosphate), and 3-8% zinc oxide.) Flame retardant 2 Bisphenol A bis(diphenyl phosphate) Flame retardant 3 ADK STAB FP2200 Antioxidant 1 AO1010 Antioxidant 2 AO168 Antistatic agent Glyceryl Monostearate Nucleating agent Sodium benzoate Light stabilizer UV-770 Anti-drip agent Teflon (PTFE) encapsulated by Styrene-Ancrylonitrile copolymer

[0187] Polypropylene was pre-mixed with additives and the mixture was extruded using a twin-screw extruder to obtain pellets. The pellets were dried at 100° C. for 3 h and injection molded using FANUC injection molding machine (S-2000i) to prepare test specimens.

[0188] The MFI of the composition was measured according to ISO1133-1:2011 (2.16 kg/230° C.).

[0189] The flame retardancy was measured according to the UL94 test standard at a sample thickness of 3 mm, 1.5 mm and 0.8 mm. The samples were conditioned at 23° C. and 50% relative humidity for 48 hours prior to testing or at 70° C. and 50% relative humidity for 168 hours. The sample bars were burnt at the gated end for Vx evaluation.

[0190] Charpy impact strength was measured according to ISO 179-1:2010 at 23° C. by Toyoseiki Digital Impact DG-UB equipped with a pendulum of 2 J (test geometry: 80*10*4 mm).

[0191] Flexural modulus was measured according to ISO 178:2010 (parallel; test geometry: 80*10*4 mm).

[0192] Tensile tests were carried out at room temperature according to ISO 527-1:2012.

[0193] Results are summarized in Tables 2 and 3. In Table 2, the propylene-based polymer is a propylene homopolymer and the glass fiber is a long glass fiber. In Table 3, the propylene-based polymer is a mixture of a propylene homopolymer and a heterophasic propylene copolymer and the glass fiber is a short glass fiber.

TABLE-US-00002 TABLE 2 Unit CE1 Ex2 CE3 CE4 Ex5 Ex6 Ex7 CE5 Polypropylene 1 wt % 60.77 60.77 79.27 78.6 68.77 58.77 48.77 47.6 Glass fiber 1 wt % 20 20 10 20 30 30 Adhesion wt % 1.5 1.5 1.5 1.5 1.5 2.0 promoter Flame wt % 17 15 20 17 17 17 17 retardant 1 Flame wt % 2 2 2 2 2 retardant 2 Flame 20 retardant 3 Antioxidant 1 wt % 0.06 0.06 0.06 0.05 0.06 0.06 0.06 0.2 Antioxidant 2 wt % 0.06 0.06 0.06 0.05 0.06 0.06 0.06 0.2 Antistatic wt % 0.25 0.25 0.25 0.25 0.25 0.25 aqent Nucleating wt % 0.06 0.06 0.06 0.06 0.06 0.06 agent Light wt % 0.3 0.3 0.3 0.3 0.3 0.3 stabilizer Anti-drip wt % 0.3 agent MFR g/10 min 15.47 17.19 30.63 27.02 21.647 16.509 11.507 7.92 FR (3 mm) V0 V0 V0 V0 V0 V0 V0 23° C., 48 h FR (3 mm) V0 V0 V0 V0 V0 V0 V0 70° C., 168 h FR (1.5 mm) V2 V1 V2 V1 V0 V0 V0 V0 23° C., 48 h FR (1.5 mm) V2 V1 V2 V1 V0 V0 V0 V0 70° C., 168 h FR (0.8 mm) Fail 23° C., 48 h FR (0.8 mm) Fail 70° C., 168 h Charpy KJ/m2 7.3 7.6 1.5 1.31 4.7 7.2 8.9 9.0 Impact @ 23 C (notched) Flexural Mpa 5192.6 4777.56 2121.2 2005 3275.44 5042.46 7417 7431 modulus

[0194] From the comparison of CE1 versus Ex2 using the same amounts of flame retardant, it can be understood that the use of the combination of FR1 and FR2 (Ex2) results in a better flame retardancy than the use of only FR1 (CE1) in glass fiber filled composition.

[0195] From the comparison of CE3 and CE4, it can be understood that the use of the combination of FR1 and FR2 (CE4) results in a better flame retardancy than the use of only FR1 (CE3) also in non-glass fiber filled composition. However, from the comparison of CE4 versus Ex5, Ex6 and Ex7 wherein the amount of glass fibers is changed, it can be understood that the presence of the glass fibers results in a better flame retardancy. Thus, the use of the combination of FR1 and FR2 in a glass fiber filled composition achieves a very good flame retardancy.

[0196] From the comparison of CE5 with Ex. 7, it can be seen that Ex. 7 balances a higher melt flow (as compared to CE5) with a good impact, flexural modulus and flame retardancy.

TABLE-US-00003 TABLE 3 Unit Ex8 Ex9 Ex10 Ex11 Ex12 Polypropylene 1 wt % 48.57 47.82 47.07 35.2 35.2 Polypropylene 2 wt % 5.5 4.75 4 Polypropylene 3 wt % 31.87 26.87 Glass fiber 2 wt % 20 20 20 10 15 Adhesion promoter wt % 1.5 1.5 1.5 Flame retardant 1 wt % 21 22.5 24 19 19 Flame retardant 2 wt % 3 3 3 3.5 3.5 Antioxidant 1 wt % 0.06 0.06 0.06 0.06 0.06 Antioxidant 2 wt % 0.06 0.06 0.06 0.06 0.06 Antistatic agent wt % 0.25 0.25 0.25 0.25 0.25 Nucleating agent wt % 0.06 0.06 0.06 0.06 0.06 MFR g/10 min 17.39 16.33 15.66 19.55 16.02 FR (3 mm) V0 V0 23° C., 48 h FR (3 mm) V0 V0 70° C., 168 h FR(1.5 mm) V0 V0 V0 V1 V0 23° C., 48 h FR(1.5 mm) V0 V0 V0 V1 V0 70° C., 168 h FR (0.8 mm) V2 V0 V0 23° C., 48 h FR (0.8 mm) V2 V0 V0 70° C., 168 h Charpy KJ/m2 7.7 7.6 7.7 4.39 4.37 Impact @ 23 C (notched) Charpy KJ/m2 41.8 40.3 35.2 15.28 12.68 Impact @ 23 C (unnotched) Tensile Mpa 5725.2 5851 5909.7 2738.84 3533.3 modulus Tensile Mpa 71.4 70.7 70.2 29.97 33.608 strength @ break Tensile % 2.58 2.52 2.57 1.86 1.599 elongation

[0197] From the comparison of Ex8-10, it can be understood that the higher amount of FR1 in combination with FR 1B results in a better flame retardancy.

[0198] From the comparison of Ex 11 and Ex12, it can be understood that the higher amount of glass fiber results in a better flame retardancy.