POLYCARBONATE-ASA BLENDS WITH ANTISTATIC PROPERTIES USING SULFONATED ALKANES

Abstract

The present invention relates to thermoplastic molding compositions comprising at least one aromatic polycarbonate (component A), at least one styrene graft polymer (component B), at least one thermoplastic styrene copolymer (component C), at least one sulfonated alkane, having from 6 to 40 carbon atoms, as antistatic agent (component D) and also where appropriate one or more of the optional components E and/or F.

Claims

1-14. (canceled)

15. A thermoplastic molding composition comprising the following components: a) 1 to 97.5% by weight, based on the thermoplastic molding composition, of at least one aromatic polycarbonate A; b) 1 to 97.5% by weight, based on the thermoplastic molding composition, of one or more graft polymer B made from: b1) 40 to 80% by weight, based on the graft polymer B, of an graft base made from an elastomeric polymer B1 based on alkyl acrylates having from 1 to 8 carbon atoms in the alkyl radical, and having a glass transition temperature below 0 C.; b2) 20 to 60% by weight, based on the graft polymer B, of a graft B2 made from b21) 60 to 95% by weight, based on the graft B2, of styrene or of substituted styrenes B21 of the formula I: ##STR00007## wherein: R is C.sub.1-C.sub.8-alkyl or hydrogen; R.sup.1 is C.sub.1-C.sub.8-alkyl or hydrogen, with the provision that not both of R and R.sup.1 are hydrogen; and n is 1, 2, or 3; or a mixture of these compounds; and b22) 5 to 40% by weight, based on the graft B2, of at least one unsaturated nitrile B22; c) 1 to 97.5% by weight, based on the thermoplastic molding composition, of at least one thermoplastic copolymer C made from: c1) 60 to 85% by weight, based on the thermoplastic copolymer C, of styrene or of substituted styrenes C1 of the formula I, or a mixture of these compounds; and c2) 15 to 40% by weight, based on the thermoplastic copolymer C, of at least one unsaturated nitrile C2; d) 0.5 to 10% by weight, based on the thermoplastic molding composition, of at least one antistatic agent D selected from sulfonated alkanes, wherein the at least one antistatic agent D is selected from secondary alkane sulfonates, having from 6 to 40 carbon atoms; e) 0 to 50% by weight, based on the thermoplastic molding composition, of at least one filler E; and f) 0 to 40% by weight, based on the thermoplastic molding composition, of at least one further additive F.

16. The thermoplastic molding composition according to claim 15, wherein the at least one aromatic polycarbonate A is based on biphenols of the formula II: ##STR00008## where X is a single bond, C.sub.1-C.sub.3-alkylene, C.sub.2-C.sub.3-alkylidene, C.sub.3-C.sub.6-cycloalkylidene, or else S or SO.sub.2.

17. The thermoplastic molding composition according to claim 15, wherein the graft bases B1 of the graft polymer B is composed of: b11) 70 to 99.9% by weight, based on the graft base B1, of at least one alkyl acrylate B11 having from 1 to 8 carbon atoms in the alkyl radical; b12) 0 to 29.5% by weight, based on the graft base B1, of another copolymerizable monoethylenically unsaturated monomer B12; and b13) 0.1 to 5% by weight, based on the graft base B1, of a copolymerizable, polyfunctional, crosslinking monomer B13; wherein the entirety of B11, B12, and B13 gives 100% by weight.

18. The thermoplastic molding composition according to claim 15, wherein the copolymer C is composed of 70 to 83% by weight, based on the copolymer C, of styrene and from 17 to 30% by weight, based on the copolymer C, of acrylonitrile.

19. The thermoplastic molding composition according to claim 15, wherein the thermoplastic molding composition comprises from 2 to 5% by weight of at least one antistatic agent D wherein the at least one antistatic agent D is selected from sulfonated alkanes according to the following formula IV: ##STR00009## wherein x and y are, independently from each other, a number from 1 to 38, with the provision that x+y is a number from 5 to 39; and M is selected from hydrogen, alkali metal salt, or earth alkali metal salt.

20. The thermoplastic molding composition according to claim 15, wherein the composition comprises from 1 to 50% by weight, based on the thermoplastic molding composition, of at least one filler E selected from particulate mineral fillers E1 and fibrous fillers E2.

21. A process for producing a thermoplastic molding composition according to claim 15, wherein the components A to D and, optionally, components E and F are mutually mixed with one another in any desired order at temperatures of 100 to 300 C.

22. A molding, fiber, or film made from a thermoplastic molding composition according to claim 15.

23. The molding, fiber, or film according to claim 22, wherein the the molding, fiber, or film is an automotive component or part of electronic equipment.

24. The molding, fiber, or film according to claim 22, wherein the the molding, fiber, or film is a motor vehicle interior.

25. A process for imparting antistatic properties into a thermoplastic molding composition by incorporating a secondary alkane sulfonate having from 6 to 40 carbon atoms as antistatic agent D in the thermoplastic molding composition, wherein the thermoplastic molding composition comprises: a) 1 to 97.5% by weight, based on the thermoplastic molding composition, of at least one aromatic polycarbonate A; b) 1 to 97.5% by weight, based on the thermoplastic molding composition, of one or more graft polymer B made from: b1) 40 to 80% by weight, based on the graft polymer B, of an graft base made from an elastomeric polymer B1 based on alkyl acrylates having from 1 to 8 carbon atoms in the alkyl radical, on ethylene-propylene, on dienes, or on siloxanes, and having a glass transition temperature below 0 C.; b2) 20 to 60% by weight, based on the graft polymer B, of a graft B2 made from: b21) 60 to 95% by weight, based on the graft B2, of styrene or of substituted styrenes B21 of the formula I: ##STR00010## wherein: R is C.sub.1-C.sub.8-alkyl or hydrogen; R.sup.1 is C.sub.1-C.sub.8-alkyl or hydrogen, with the provision that not both of R and R.sup.1 are hydrogen; and n is 1, 2 or 3; or a mixture of these compounds; and b22) 5 to 40% by weight, based on the graft B2, of at least one unsaturated nitrile B22; and c) 1 to 97.5% by weight, based on the thermoplastic molding composition, of at least one thermoplastic copolymer C made from: c1) 60 to 85% by weight, based on the thermoplastic copolymer C, of styrene or of substituted styrenes C1 of the formula I, or a mixture of these compounds; and c2) 15 to 40% by weight, based on the thermoplastic copolymer C, of at least one unsaturated nitrile C2.

Description

[0193] FIG. 1 shows the charge decay curves of PC/ASA samples (Luran SC KR2863C) with different antistatic agents according to the examples C1 to C4 and V1. The decay curves show the field strength E given in kV/m (kilo volt per meter) (on y axis) in dependency of the time t in s (seconds) (on x axis). The examples C1 to C4 comprise different antistatic agent CESA-stat (Clariant). The example V1 comprises the antisatic agent Armostat 3002 (AKZO) which is a sodium sec. alkanesulfonate.

[0194] The following examples and claims illustrate the invention.

EXAMPLES

[0195] A Preparation of the Molding Compositions

[0196] The following components were used: [0197] Luran SC KR2863C in VW Perl Grey KU Y20Styrolution color GR37039 which is a blend of polycarbonate and ASA characterized by a melt volume-flow rate of 16-18 cm.sup.3/10 min (measured at 260 C./5 kg according to ISO1133). The blend is composed of 70% by weight of polycarbonate; 10.5% by weight of Luran VLL1970; 9% by weight of Luran S VL8; 8% by weight of Luran S VL18. Luran VLL1970, Luran S VL8, and Luran S VL18 are ASA copolymers available from Ineos Styrolution (Frankfurt). Thus, the ASA/PC blend Luran SC KR2863C refers to the components A, B, and C. [0198] 0.5% by weight Loxiol G70S (commercial demolding agent) and [0199] 2% by weight pigments and stabilizers.

[0200] The following antistatic agents (referring to component D) were used [0201] D1: Antistatic agent CESA-stat OCA 0025589, OCA 0025693 and OCA 0025694 (from Clariant, Germany), which are permanent antistatic agent master batches containing a polyether-polyamide block copolymer, product form: master batch granules [0202] D2: Irgastat P22 (BASF SE, Germany), which is a permanent antistatic agent based on a polyether-polyamide block copolymer, product form: granules [0203] D3: Armostat 3002 (AKZO) (sodium sec. alkanesulfonate, CAS No 68608-15-1), product form: flakes, Armostat 3002 is dried before use

[0204] The PC/ASA blend and the antistatic component D were mixed in a twin-screw extruder at from 250 to 280 C., extruded, cooled and pelletized. The dried pellets were processes at 260 C. to give testing samples and automobile plaques of DIN A5 format. The compositions are summarized in the following table 1:

TABLE-US-00001 TABLE 1 Molding compositions - Part I (all values given in % by weight) C1 C2 C3 C4 V1 Luran SC 97.5 87.5 92.5 90.5 93.5 KR2863C Loxiol 0.5 0.5 0.5 0.5 0.5 pigments and 2 2 2 2 2 stabilizers D1 10 5 7 (OCA (OCA (OCA 0025589) 0025693) 0025694) D3 4

[0205] Further the following compositions A to H were prepared as described above. The pigments were a mixture comprising chrome titan yellow, iron oxide red, phthalo green, carbon black and titanium dioxide.

[0206] Tinuvin 329 (BASF SE) is a UV-light stabilizer comprising the chemical compound 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol.

TABLE-US-00002 TABLE 2 Molding compositions - Part II (all values given in % by weight) A B C D E F G H Polycarbonat 61.7 61.1 60.5 59.8 63.9 63.1 61.9 58.6 Luran 11.6 11.5 11.4 11.3 11.9 11.8 11.6 11.0 VLL1970 Luran 7.1 7.0 7.0 6.9 7.3 7.2 7.1 6.7 S VL8 Luran 7.9 7.8 7.7 7.7 8.1 8.0 7.9 7.4 S VL18 Tinuvin 329 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Fatty acid 0.4 0.4 0.4 0.4 0.5 0.5 0.4 0.4 ester Pigments 5.7 5.6 5.5 5.4 5.8 5.8 5.7 5.4 D1 5.0 6.0 7.0 8.0 D2 5.0 10.0 D3 2.0 3.1 Sum 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

[0207] B Methods of Measurement

[0208] a. The flowabilitiy of the compositions was determined as melt volume flow rate (MVR) according to DIN 53 735 or ISO1133 at 260 C. with 5 kg load.

[0209] Further, the melt volume flow rate (MVR) for the compositions A to F was determined at different temperatures in the range of 220 to 300 C. The results are summarized in the following table 3.

TABLE-US-00003 TABLE 3 Influence of temperature on MVR - all values given in cm.sup.3/10 min A B C D E F MVR 220 C., 5 kg 3.14 3.15 3.45 3.42 2.99 3.66 MVR 230 C., 5 kg 6.16 6.18 6.52 6.75 5.69 6.44 MVR 240 C., 5 kg 10.66 10.99 11.78 12.09 11.40 9.66 MVR 250 C., 5 kg 15.70 16.60 18.40 18.10 17.70 19.50 MVR 260 C., 5 kg 29.40 29.79 34.33 31.32 29.94 29.97 MVR 270 C., 5 kg 44.98 48.18 52.90 53.56 42.00 52.05 MVR 280 C., 5 kg 75.12 82.04 89.41 89.75 89.70 66.59 MVR 300 C., 5 kg 163.50

[0210] b. The Vicat B heat distortion temperature was determined from the Vicat softening point determined on standard small specimens according to DIN 53 460, using a force of 49.05 N and a temperature rise at 50 K per hour.

[0211] c. Modulus of elasticity was determined according to ISO 527 on tensile specimens by tensile testing at 23 C. Tensile stress at yield was determined to ISO 527 at 23 C.

[0212] d. Notched impact strength a.sub.k was tested according to ISO 179 1 eA at 23 C., on ISO specimens.

[0213] e. The weathering resistance of test specimens were determined according to PV1303 (5 cycles). For that purpose test specimens (60602 mm, produced to ISO 294 in a family mold at a melt temperature of 260 C. and a mold temperature of 60 C.) were subjected to weatherization by xenon-arc test to PV1303 5 cycles. Following the 350 h weatherization the surface gloss of all samples was measured to German standard specification DIN 67530 at a 60 viewing angle. The surface was evaluated in terms of the gray scale (5: no change, 1: massive change) to ISO 105-A02 (1993). Further, the color data Yellow index, and the CIELAB values DE*, DL*, Da* and Db*, also referred to as DE, DL, Da and Db, were measured.

[0214] The results before and after weathering are summarized in Table 4.

TABLE-US-00004 TABLE 4 Weathering resistance of molding compositions- Part I Time Yellow- Gray Comp. [h] index Gloss DE DL Da Db scale C1 0 6.6 88.9 0.0 0.0 0.0 0.0 350 11.5 84.9 2.3 0.1 0.4 2.2 4.0 C2 0 6.7 99.7 0.0 0.0 0.0 0.0 350 10.1 93.0 1.6 0.3 0.3 1.6 4.0 C3 0 6.8 97.3 0.0 0.0 0.0 0.0 350 14.5 95.1 3.6 0.5 0.6 3.5 3 to 4 C4 0 6.7 90.2 0.0 0.0 0.0 0.0 350 21.9 78.9 5.9 1.2 0.7 6.8 2 V1 0 6.1 82 0 0 0 0 350 20.5 61.4 6.62 1.15 0.78 6.47 2

[0215] f. The antistatic properties were determined by the determination of the charge decay. For this samples of 80 mm by 2 mm are conditioned for 24 h at 23 C. and 50% moisture. Then the samples are loaded with 20 to 70 kv for 15 seconds (s) and the charge decay is measured. The charge decay was classified as follows:

TABLE-US-00005 Charge decay Time t() Resistivity [Ohm] Very fast <100 sec <10.sup.11 Medium 100-200 sec 10.sup.11-10.sup.16 Poor >7.5 min >10.sup.16

[0216] The charge decay curves of Examples C1 to C4 and V1 are shown in FIG. 1. The results are given in the following table 5.

TABLE-US-00006 TABLE 5 Antistatic properties of molding compositions- Part I C1 C2 C3 C4 V1 Charge No Fast de- No Very fast Very fast decay decay cay, 0 V decay decay decay after 180 O V after O V after sec 50 sec 50 sec

[0217] The permanent antistatic agents from Clariant (CESA-stat) need to be added in an amount of more than 7% by weight (C2 and C4) in order to obtain a sufficient antistatic effect. Otherwise, a sufficient antistatic effect can be obtained using 4% by weight or less Armostat antistatic agent.

[0218] The antistatic properties of compositions A to H are summarized in table 6.

TABLE-US-00007 TABLE 6 Antistatic properties of molding compositions- Part II A B C D E F Electrostatic cross 91 64 55 55 43 46 charge, [kV/m] Half life [s] 105 23 29 20 10 11 Remaining charge 56 22 20 19 13 14 after 60 s, [kV/m] Remaining charge 11 3 3 3 1 2 after 600 s, [kV/m] Remaining charge 0 0 0 0 0 0 after 3600 s, [kV/m] Decay [%] 100 100 100 100 100 100

[0219] The molding compositions E and F according to the invention show a faster charge decay, in particular in the first 60 seconds, in comparison to the moldings with the permanent antistatic agent CESA-stat. The lower level of antistatic agent (2-3% by weight) in E and F also leads to higher Vicat temperature (see Table 8).

[0220] The PC/ASA compositions E and F and V1 exhibit a sufficient and improved antistatic affect. Also the antistatic finishing using CESA-stat is more expensive than the antistatic finishing with Armostat. For example an dosage of 5% by weight CESA-stat (see comparative example C3) cannot lead to an sufficient antistatic modification. The permanent antistatic agents require an higher level of about 7% by weight or more (see comparative example C2 and C4) to produce an sufficient antistatic effect, wherein this antistatic modification is much more expensive.

[0221] g. The heat aging was determined at 90 C. for 1000 hours using 3 automobile plate the surface appearance was determined by loss of gloss. Heat aging was conducted at 90 C. for 1,000 h and at 500 C. fpr 1,000 h. Gloss and color of the samples before and after aging was measured. The heat aging data did not show any change of gloss and color before and after aging.

[0222] h. The emission was determined according to internal method via determination of the total volatile organic compounds (TVOC) given in ppm.

[0223] C Further Test Results

[0224] The properties of the moldings were determined as described above using suitable test specimens produced from the compositions C1 to C4 and V1 and A to H. The following results were obtained.

TABLE-US-00008 TABLE 7 Properties of molding compositions- Part I C1 C2 C3 C4 V1 MVR 16 29 26 24 30 [cm.sup.3/10 min] Tensile Modulus 2420 2183 2437 2248 2266 [MPa] Strength at yield 58 53 58 56 56 [MPa] Elongation at break 70 116 19 129 19 [%] Notched impact strength 74 59 48 96 72 [kJ/m2] Vicat softening point [ C.] 129 120 128 122 124 TVOC [ppm] 17 23 14 33 27

TABLE-US-00009 TABLE 8 Properties of molding compositions- Part II A B C D E F G H MVR, 260/5 27.5 29.2 30.8 32.9 27.3 33.5 31.0 39.1 [cm.sup.3/10 min] Tensile Modulus 2424 2405 2397 2361 2448 2431 2493 2338 [MPa] Strength at yield 57.2 56.8 56.7 56.0 58.9 57.5 59.3 56.6 [MPa] Notched impact 64.1 65.2 70.6 63.0 65.0 60.5 41.8 23.4 strength [kJ/m2] Vicat softening 124.9 125.4 121 121.5 125.6 125.6 123.0 120.5 point [ C.]

[0225] Generally, the mechanical data show good results and the mechanical properties are not adversely affected by addition of the dry alkylsulfonate antistatic agent. Also, thermal stability properties of the antistatic compositions of the invention, e.g. shown by Vicat point, were not significantly affected versus reference C1.

[0226] The tested polymer blend compositions are process stable up to 270 C., preferably up to 300 C. and do not exhibit increase emissions (TVOC).