Thermoplastic styrene copolymer resin composition with improved UV resistance

Abstract

Thermoplastic styrene copolymer resin composition comprising: (a1) at least one styrene-acrylonitrile copolymer component A1, (a2) at least one acrylonitrile styrene acrylate graft copolymer A2 as impact modifier, (a3) optionally at least one thermoplastic polymer A3 other than components A1 and A2, (b) at least one transition metal oxide pigment B, (cl) at least one hindered amine UV light stabilizer C1, (c2) optionally at least one UV absorber C2 different from Cl, (d) optionally further polymer additives D, other than components B, C1, C2, and E, and (e) optionally one metal scavenger component E, wherein at least 99.0 wt.-% of the transition metal oxide pigment B consist of transition metal atoms and oxygen atoms.

Claims

1. Thermoplastic styrene copolymer resin composition comprising: (a1) at least one styrene-acrylonitrile copolymer component A1, (a2) at least one acrylonitrile styrene acrylate graft copolymer A2 as impact modifier, (a3) optionally at least one thermoplastic polymer A3 other than components A1 and A2, (b) at least one transition metal oxide pigment B, (c1) at least one hindered amine UV light stabilizer C1, (c2) optionally at least one UV absorber C2 different from C1, (d) optionally further polymer additives D, other than components B, C1, C2, and E, and (e) optionally one metal scavenger component E, wherein at least 99.0 wt.-% of the transition metal oxide pigment B consist of transition metal atoms and oxygen atoms.

2. The thermoplastic styrene copolymer resin composition according to claim 1, comprising 70.0 to 99.4 wt.-%, based on the total weight of the composition, of components A1, A2, and optionally A3, and comprising 0.5 to 7.0 wt.-%, based on the total weight of the composition, of component B, and comprising 0.1 to 3.0 wt.-% based on the total weight of the composition, of components C1 and optionally C2.

3. The thermoplastic styrene copolymer resin composition according to claim 1, comprising (i) of from 87.5 to 99.3 wt.-%, based on the total weight of the composition, of A1, A2, and optionally A3, (ii) of from 0.4 to 7.0 wt.-%, based on the total weight of the composition, of component B, (iii) of from 0.1 to 1.5 wt.-%, based on the total weight of the composition, of at least one hindered amine UV light stabilizer C1 and optionally of from 0.1 to 1.5 wt.-% of at least one UV absorber C2 other than C1, (iv) of from 0.1 to 2.5 wt.-%, based on the total weight of the composition, of at least one further polymer additive D, and (v) of from 0.1 to 1.5 wt.-% based on the total composition of at least one metal scavenger component E.

4. The thermoplastic styrene copolymer resin composition according to claim 1, wherein the styrene-acrylonitrile copolymer component A1 has an acrylonitrile content of from 5 to 35 wt.-% based on the total weight of the styrene-acrylonitrile copolymer component A1.

5. The thermoplastic styrene copolymer resin composition according to claim 1, wherein the impact-modified graft rubber acrylonitrile styrene acrylate A2 comprises: a graft base of from 40 to 90 wt.-% based on the total weight of the impact-modified graft rubber acrylonitrile styrene acrylate A2 comprising: (i) from 70 to 99.9 wt.-% of n-butyl acrylate based on the total weight of the graft base, (ii) from 0 to about 30 wt.-% of styrene based on the total weight of the graft base, and (iii) from 0.1 to 5 wt.-% of a crosslinking agent based on the total weight of the graft base; and a graft of from 10 to 60 wt.-% comprising: (iv) from 65 to 95 wt.-% of styrene based on the total weight of the graft, and (v) from 5 to 35 wt.-% of acrylonitrile based on the total weight of the graft.

6. The thermoplastic styrene copolymer resin composition according to claim 1, which comprises from 1 to 70 wt.-% based on the total weight of components A1 and A2 of at least one thermoplastic polymer A3 selected from the group consisting of polycarbonate (PC), polyamide (PA), and mixtures thereof.

7. The thermoplastic styrene copolymer resin composition according to claim 1, wherein the transition metal oxide pigment component B is iron oxide.

8. The thermoplastic styrene copolymer resin composition according to claim 1, wherein component C1 is a hindered amine UV light stabilizer according to the following formula (Ia) and/or formula (Ib): ##STR00009## wherein R1 is H or methyl; each R2 is individually selected from the group consisting of hydrogen, methyl, and ethyl; R3 is selected from the group consisting of linear C.sub.1- to C.sub.18-esters which are connected to formula (Ia) via the oxygen atom of the ester function; and with R4 being selected from the group consisting of C.sub.1- to C.sub.10-alkylene.

9. The thermoplastic styrene copolymer resin composition according to claim 1, wherein at least one component E is present, which is a metal scavenger comprising at least one hydrazide group.

10. The thermoplastic styrene copolymer resin composition according to claim 1, wherein the composition comprises only one hindered amine UV light stabilizer C1 and no UV absorber C2.

11. The thermoplastic styrene copolymer resin composition according to claim 1, wherein the composition shows a color shift dE of equal to or lower than 3.0 upon UV irradiation according to ISO-4892-2 after 6000 hours.

12. A method for preparing the thermoplastic styrene copolymer resin composition according to claim 1, comprising the step of mixing components A1, A2, B, C1, and optionally C2, A3, D, and E at temperatures of from 100° C. to 300° C. and a pressure of from 1 to 50 bar, in any order, followed by a kneading or extrusion step.

13. The method for preparing the thermoplastic resin composition according to claim 12, wherein at least two of components A1, A2, B, C1, and optionally A3, C2, D, and E are premixed to form a masterbatch.

14. A molded article prepared from the thermoplastic styrene copolymer resin composition according to claim 1.

Description

FIGURES

(1) FIG. 1 shows a scanning electron microscope image of an iron oxide red pigment sample Colortherm® Red 110M.

(2) FIG. 2 discloses a scanning electron microscope image of an iron oxide red pigment sample Sicotrans® Red K 291.

(3) FIG. 3 shows an energy-dispersive X-ray spectroscopy spectrum of an iron oxide red pigment sample Sicotrans® Red K 291.

(4) FIG. 4 discloses an energy-dispersive X-ray spectroscopy spectrum of an iron oxide red pigment sample Colortherm® Red 110M.

EXAMPLES

(5) The following examples and claims further illustrate the invention.

(6) Raw Materials

(7) Luran® S 776 SE is a commercially available ASA copolymer from INEOS Styrolution.

(8) Palatinol® 10-P (phthalic acid ester of 010 alcohols) can be purchased from BASF SE.

(9) Colortherm® Red 110M is a micronized iron oxid red pigment, commercially available by Supplier Lanxess (Germany), produced according to Laux process.

(10) Sicotrans® Red K 291 is an iron oxide red pigment produced via precipitation process available by BASF SE, Germany.

(11) Tinuvin® P (2-(2H-benzotriazol-2-yl)-p-cresol, CAS-No. 2440-22-4) is a commercial UV-absorber that can be purchased from BASF SE.

(12) Tinuvin® 770 (Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, CAS-No. 52829-07-9) can be purchased from BASF SE.

(13) Irganox® MD 1024 (3-(3,5-ditert-butyl-4-hydroxyphenyl)-N′43-(3,5-ditert-butyl-4-hydroxy-phenyl)-propanoylFpropanehydrazide, CAS-No. 251-156-3) is a metal scavenger that can be purchased from BASF SE (Germany).

(14) Characterization of Iron Oxide Pigments

(15) Iron oxide pigment samples of Colortherm® Red 110M and Sicotrans® Red K 291 have been analyzed by energy-dispersive X-ray spectroscopy (EDX) and Wavelength-dispersive X-ray spectroscopy (WDX) using a Zeiss Ultraplus scanning electron microscope. Primary energy used 20 kV. Samples were pressed to pellets using a KBr press. Additionally particle sizes of the iron oxide pigments have been analyzed using a Zeiss Leo 1530.

(16) EDX analysis of Sicotrans® Red K 291 resulted in EDX spectra as disclosed exemplary in FIG. 3. The elements iron and oxygen were identified. The following atomic ratios of oxygen and iron were measured:

(17) TABLE-US-00001 Position c Oxygen (K-line) Iron (K-Line) Sicotrans Red K2915(1)_pt1 61.0 39.0 Sicotrans Red K2915(1)_pt2 60.9 39.1 Sicotrans Red K2915(1)_pt3 59.8 40.2 Sicotrans Red K2915(1)_pt4 59.2 40.8 Sicotrans Red K2915(2)_pt1 n.d. Sicotrans Red K2915(2)_pt2 59.4 40.6 Sicotrans Red K2915(2)_pt3 59.0 41.0 Sicotrans Red K2915(2)_pt4 58.8 41.2 Average 59.7 40.3

(18) No other elements could be identified in the Sicotrans® Red K 291 samples using WDX measurements. Particle sizes of Sicotrans® Red K 291 were measured (FIG. 2) resulting in an average particle size of 48 nm+1-8 nm based on the evaluation of 17 particles. EDX analysis of Colortherm® Red 110M resulted in EDX spectra as disclosed exemplary in FIG. 4. The elements iron, silica and oxygen were identified. The following atomic ratios of oxygen, silica, and iron were measured:

(19) TABLE-US-00002 Oxygen Silica Iron Position (K-Line) (K-Line) (K-Line) Colotherm Red 110M(1)_pt1 61 1.4 37.6 Colotherm Red 110M(1)_pt2 61 1.5 37.5 Colotherm Red 110M(1)_pt3 59.1 1.5 39.4 Colotherm Red 110M(1)_pt4 56.9 1.3 41.8 Colotherm Red 110M(1)_pt5 55.9 1.5 42.6 Colotherm Red 110M(2)_pt1 60.2 1.3 38.5 Colotherm Red 110M(2)_pt2 55.7 2.7 41.6 Colotherm Red 110M(2)_pt3 55.7 3.1 41.2 Colotherm Red 110M(2)_pt4 62.8 1.4 35.8 Colotherm Red 110M(2)_pt5 58.6 1.4 40 Colotherm Red 110M 2(1)_pt1 60.3 1.4 38.3 Colotherm Red 110M 2(1)_pt2 59.1 1.7 39.2 Colotherm Red 110M 2(1)_pt3 61.2 5.3 33.5

(20) No other elements could be identified in the Colortherm® Red 110M samples using WDX measurements. Particle sizes of Colortherm® Red 110M were measured (FIG. 1) resulting in an average particle size of 82 nm+1-7 nm based on the evaluation of 23 particles.

(21) Sample Preparation

(22) For compounding a Coperion ZSK 25 extruder was used and for injection molding an Arburg machine. All test specimens have the following dimensions: 75×50 mm.

(23) Testing

(24) Artificial weathering according to ISO 4892-2A(1) was conducted under the following conditions:

(25) TABLE-US-00003 Irradiance wavelength nm 300 to 400 340 Light strength W/m.sup.2 60 ± 2  0.51 ± 0.02 Black board temperature ° C. 65 ± 3  Relative humidity % 50 ± 10 Cycle time for Duration for min  18 water spray water spray Duration for not min 102 water spray Xenon filter Inner — Boro. S. (S-type) combination Outer — Boro. S. (S-type)

(26) For artificial weathering according to ISO 4892-3 a Q-UVse tester equipped with UVA-340 lamps was used. Each cycle consists of 8 h irradiation (0.76 W/m.sup.2, 60° C. black panel temperature) and 4 h condensation (no irradiation, 50° C. black panel temperature).

(27) For color measurements a commercial testing device Datacolor 110 was used.

(28) Example 1 comprising Sicotrans® Red K 2915 shows significantly higher UV resistance compared to comparative example 1 comprising natural Colortherm® Red 110M. Samples have been tested according to two different artificial weathering methods: ISO 4892-2 and ISO 4892-3. Total color shift has been measured every 1000 h.

(29) TABLE-US-00004 Comparative Example 1 Example 1 Component A (thermoplastic 95.69 95.69 resin) Luran ® S 776SE Component D (additive) 1.44 1.44 Palatinol ® 10-P Component B (Pigment) 1.91 Sicotrans ® Red K 2915 Component B (Pigment) 1.91 Colortherm Red 110M Component C1 (HALS) 0.48 0.48 Tinuvin ® 770 Component C2 (UV absorber) 0.48 0.48 Tinuvin ® P dE after 4000 h (ISO 4892-2) 0.43 3.12 dE after 5000 h (ISO 4892-2) 0.66 — dE after 6000 h (ISO 4892-2) 1.73 3.04 dE after 5000 h (ISO 4892-3) 1.1 3.4 dE after 6000 h (ISO 4892-3) 0.8 4.3