STABILIZER COMPOSITION FOR SILYL-MODIFIED POLYMER SEALANTS

Abstract

The present invention is directed to stabilizer compositions comprising at least one oxalanilide UV absorber, at least one hindered amine light stabilizer (HALS), at least one phenolic antioxidant and optionally further components. Said stabilizer compositions are preferably used in sealants or adhesives based on silyl-modified polymers (SMP). The invention is also directed to a polymer composition based on silyl-modified polymers (SMP) comprising the inventive stabilizer combination of oxalanilide UV absorber, hindered amine light stabilizer (HAL S) and phenolic antioxidant.

Claims

1. Stabilizer composition comprising: (A) an UV absorber as component A, wherein the UV absorber A is composed of one or more oxalanilide compounds according to formula (I) ##STR00018## wherein R.sub.a and R.sub.b are independently of one another selected from hydrogen, alkyl groups having from 1 to 20 carbon atoms, alkoxy groups having from 1 to 20 carbon atoms and 1 to 4 oxygen atoms; (B) a hindered amine light stabilizer as component B, (C) an antioxidant as component C, wherein the antioxidant C is composed of one or more phenolic compounds according to the formulas (III)a and/or (III)b: ##STR00019## wherein R.sub.x and R.sub.y are independently of one another selected from hydrogen, halogen or an alkyl group having from 1 to 10 carbon atoms; R.sub.z is selected from hydrogen or an alkyl group having from 1 to 10 carbon atoms; R.sub.w is selected from a hydroxy group, an alkoxy group having from 1 to 18 carbon atoms, a phenyl alkoxy group having from 1 to 4 alkyl carbon atoms, a cycloalkoxy group having from 5 to 8 carbon atoms, or a group of formula (III)c ##STR00020## in which Z.sub.1 and Z.sub.2 are independently of one another selected from hydrogen, an alkyl group having from 1 to 18 carbon atoms, a phenyl group and a cycloalkyl group having from 5 to 8 carbon atoms; X is selected from —O—(CH.sub.2).sub.q—O—; —(OCH.sub.2—CH.sub.2).sub.q—O—; —O—(CH.sub.2).sub.q—S—(CH.sub.2).sub.q—O; —NH—(CH.sub.2).sub.q—NH—; —NH—NH—, with q is an integer from 1 to 12, or a group ##STR00021## and p is zero or an integer from 1 to 6; (D) optionally at least one diluent as component D, and (E) optionally at least one further additive as component E.

2. Stabilizer composition according to claim 1, wherein the stabilizer composition comprises: (A) 10 to 89% by weight, based on the total stabilizer composition, of the UV absorber A; (B) 10 to 89% by weight, based on the total stabilizer composition, of the hindered amine light stabilizer B; (C) 1 to 80% by weight, based on the total stabilizer composition, of the antioxidant C; (D) optionally 0 to 50% by weight, based on the total stabilizer composition, of at least one diluent D; (E) optionally 0 to 10% by weight, based on the total stabilizer composition, of at least one further additive E.

3. Stabilizer composition according to claim 1, wherein the stabilizer composition comprises: (A) 20 to 79% by weight, based on the total stabilizer composition, of the UV absorber A; (B) 20 to 79% by weight, based on the total stabilizer composition, of the hindered amine light stabilizer B; (C) 1 to 60% by weight, based on the total stabilizer composition, of the antioxidant C.

4. Stabilizer composition according to claim 1, wherein the stabilizer composition comprises: (A) 20 to 69% by weight, based on the total stabilizer composition, of the UV absorber A; (B) 20 to 69% by weight, based on the total stabilizer composition, of the hindered amine light stabilizer B; (C) 10 to 59% by weight, based on the total stabilizer composition, of the antioxidant C; (D) 1 to 30% by weight, based on the total stabilizer composition, of the at least one diluent D.

5. Stabilizer composition according to claim 1, wherein the UV absorber A is composed of one or more oxalanilide compounds selected from compounds of the following formulas (I)-1 to (I)-7: ##STR00022##

6. Stabilizer composition according to claim 1, wherein the hindered amine light stabilizer B is composed of 65 to 95% by weight, based on component B, of at least one compound of formula (II)a, 5 to 35% by weight, based on component B, of at least one compound of formula (II)b, and 0 to 10% by weight, based on component B, of at least one compound of formula (II)c: ##STR00023## ##STR00024## wherein n and m are independently of one another a number from 0 to 100, with the proviso that n and m are not both 0; R.sub.1 is hydrogen, a cycloalkyl group having from 5 to 7 carbon atoms, or an alkyl group having from 1 to 12 carbon atoms; R.sub.2 and R.sub.3 are independently of one another selected from hydrogen, an alkyl group having from 1 to 18 carbon atoms, or are, together with the carbon atom connecting them, a 5- to 13-membered ring or are, together with the carbon atom connecting them, a group of formula (II)d ##STR00025## in which is R.sub.1 as defined above, and R.sub.4 and R.sub.5 are independently of one another selected from hydrogen, an alkyl group having from 1 to 22 carbon atoms, an oxygen radical O*, —OH, —NO, —CH.sub.2CN, benzyl, allyl, an alkyloxy group having from 1 to 30 carbon atoms, a cycloalkyloxy group having from 5 to 12 carbon atoms, a aryloxy group having from 6 to 10 carbon atoms in which additionally the aryl radical may be substituted, an arylalkyloxy group having from 7 to 20 carbon atoms in which additionally the aryl radical may be substituted, an alkenyl group having from 3 to 10 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, an acyl group having from 1 to 10 carbon atoms, halogen, unsubstituted phenyl or C.sub.1-C.sub.4-alkyl substituted phenyl;

7. Stabilizer composition according to claim 6, wherein the hindered amine light stabilizer B is composed of compounds according to formulas (II)a and (II)b and optionally (II)c, wherein n and m are independently of one another a number from 0 to 5, with the proviso that n and m are not both 0; R.sub.1 is an alkyl group having from 1 to 4 carbon atoms; R.sub.2 and R.sub.3 are, together with the carbon atom connecting them, a 6- to 12-membered cycloalkyl ring, or are, together with the carbon atom connecting them, a group of formula (II)d; R.sub.4 and R.sub.5 are independently of one another selected from hydrogen, an alkyl group having from 1 to 4 carbon atoms, an alkyloxy group having from 1 to 6 carbon atoms, a cycloalkyloxy group having from 5 to 6 carbon atoms, and an acyl group having from 1 to 4 carbon atoms.

8. Stabilizer composition according to claim 1, wherein the antioxidant C comprises a phenolic compound according to formula (III)b, wherein R.sub.x and R.sub.y are independently of one another selected from a branched alkyl group having from 1 to 6 carbon atoms; R.sub.z is selected from hydrogen or an alkyl group having from 1 to 4 carbon atoms; X is —O—(CH.sub.2).sub.q—O— with q is an integer from 2 to 4; and p is an integer from 1 to 4.

9. Stabilizer composition according to claim 1, wherein the UV absorber A comprises the oxalanilide compound according to formula (I)-1 ##STR00026## and the antioxidant C comprises the phenolic compound bis-(3,3-bis-(4′-hydroxy-3′-tert-butyl-phenyl)butanoic acid)-glycolester.

10. Process for preparing a stabilizer composition according to claim 1, wherein the components A, B, C and optionally D and/or E are mixed.

11. Use of a stabilizer composition according to claim 1 as stabilizer in sealants or adhesives based on silyl-modified polymers.

12. Polymer composition, comprising: (P) at least one polymer P selected from silyl-modified polymers; (S) a stabilizer combination S composed of an UV absorber A; a hindered amine light stabilizer B; and an antioxidant C; wherein the components A, B and C are as defined in claim 1; (F) optionally at least one filler F; (G) optionally at least one further additive G.

13. Polymer composition according to claim 12, wherein the polymer composition comprises: (P) 5 to 99% by weight, based on the total polymer composition, of the at least one polymer P selected from silyl-modified polymers; (S) a stabilizer combination S composed of 0.001 to 3% by weight, based on the total polymer composition, of the UV absorber A; 0.001 to 3% by weight, based on the total polymer composition, of the hindered amine light stabilizer B; and 0.001 to 3% by weight, based on the total polymer composition, of the antioxidant C; (F) optionally 0 to 85% by weight, based on the total polymer composition, of at least one filler F; (G) optionally 0 to 35% by weight, based on the total polymer composition, of at least one further additive G.

14. Polymer composition according to claim 12, wherein the polymer composition comprises: (P) 7.5 to 95% by weight, based on the total polymer composition, of the at least one polymer P selected from silyl-modified polymers; (S) a stabilizer combination S composed of 0.001 to 3% by weight, based on the total polymer composition, of the UV absorber A; 0.001 to 3% by weight, based on the total polymer composition, of the hindered amine light stabilizer B; and 0.001 to 3% by weight, based on the total polymer composition, of the antioxidant C; (F) 1 to 80% by weight, based on the total polymer composition, of at least one filler F; (G1) 1 to 25% by weight, based on the total polymer composition, of at least one plasticizer as further additive G1; (G2) 1 to 10% by weight, based on the total polymer composition, of at least one adhesion promoter as further additive G2; (G3) 0.01 to 3% by weight, based on the total polymer composition, of at least one catalyst as further additive G3; (G) and optionally 0 to 10% by weight, based on the total polymer composition, of at least one further additive G different from G1 to G3.

15. Polymer composition according to claim 12, wherein the silyl-modified polymer P is selected from silyl-modified polyethers according to the following formula (P-II): ##STR00027## wherein Q.sub.1, Q.sub.2 and Q.sub.3 are independently from each other selected from an alkyl group having 1 to 40 carbon atoms, and an alkyoxy group having from 1 to 10 carbon atoms, with the proviso that at least one of Q.sub.1, Q.sub.2 and Q.sub.3 is a cross-linkable hydrolysable silyl group, and n.sub.1 and n.sub.2 are independently from each other a integer from 0 to 1000, with the proviso that n.sub.1+n.sub.2 is at least 50.

16. Polymer composition according to claim 12, wherein the UV absorber A comprises the oxalanilide compound according to formula (I)-1 ##STR00028## and the antioxidant C comprises the phenolic compound bis-(3,3-bis-(4′-hydroxy-3′-tert-butyl-phenyl)butanoic acid)-glycolester.

Description

DESCRIPTION OF FIGURES

[0222] The FIGS. 1 to 4 shows the results of the statistical models (ANOVA) in view of surface cracking resistance and heat stability.

[0223] FIG. 1 shows the variation of the heat stability as a function of the concentration of the phenolic antioxidant C1.

[0224] FIG. 2 shows the variation of heat stability as a function of the concentration of HALS component B1 and UV absorber A1, at a constant C1 content of 0.1%.

[0225] FIG. 3 shows the correlation between surface cracking and heat stability, wherein the C1 loading is 0% (□ square); 0.1% (⋄ lozenge) and 0.2% (Δ triangle)

[0226] FIG. 4 shows the variation of surface cracking as a function of the concentration of A1 and C1

[0227] The present invention is further illustrated by the following examples and claims.

EXAMPLES

1. Preparation of the Stabilizer Compositions SC

[0228] The following stabilizer compositions were prepared by mixing the components in dry solid powder form. The stabilizers components A1, B1 and C1 are as defined below. The filler component D1 is a stearic acid surface treated calcium carbonate with a weight median diameter d.sub.50 of 1.7 μm, a top cut d.sub.90 of 8 μm and BET surface area of 4.5 m.sup.2/g.

TABLE-US-00001 TABLE 1 Stabilizer compositions (all amounts given in % by weight) SC1 5C2 5C3 A1 36.36 45.45 33.33 B1 27.27 45.45 33.33 C1 18.18  9.09 33.33 D1 18.18 — —

[0229] The following SMP compositions were prepared using SMP1 (Kaneka S303H, silyl-terminated polyether) and one of the stabilizer compositions SC1, SC2 or SC3, wherein the components SMP1, F1, G1, G2, G3 and G4 were as described above:

TABLE-US-00002 Component Amount [g] SMP1 29.2 SC1/SC2/SC3 0.8 F1 52.0 G1 14.6 G2 0.9 G3 0.5 G4 2.0

[0230] Corresponding SMP compositions were prepared using the reference stabilizer R1 or R2 as described below. The preparation of the SMP samples and testing of heat stability and surface cracking resistance were carried out as described below. The results are summarized in the following table 2.

TABLE-US-00003 TABLE 2 Results of surface cracking resistance for SMP samples Heat stability 110° C. Surface cracking No. Stabilizers [hours] [hours] Ex. 1/1 SC1 1800 >2000 Ex. 1/2 SC2 2000 >2000 Ex. 1/3 R1 1600 1500 Ex. 1/4 R2 1600 1500

2. Preparation and Testing of the SMP Test Samples (Statistical Modelling)

[0231] The following components were used:

Component P:

[0232] SMP1: Kaneka S303H, silyl-terminated polyether

Stabilizers S:

[0233] A1: UV absorber, 2-Ethyl-2′-ethoxy-oxalanilide (CAS-No. 23949-66-8); [0234] B1: HALS, reaction product of 2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro-20-(2,3-epoxi-propyl)dispiro-(5.1.11.2)-heneicosane-21-one and epichlorohydrin, (Hostavin® N30 from Clariant); [0235] C1: Phenolic antioxidant, bis-(3,3-bis-(4′-hydroxy-3′-tert. butylphenyl)butanic acid)-glycolester (CAS-No. 32509-66-3); [0236] R1: Reference 1 is a combination of [0237] A2 UV absorber, 2-(2′-Hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzortriazole (CAS-No. 3896-11-5), and [0238] B2 HALS, bis(2,2,6,6-tetramethyl-4-piperidinyl)decandioat (CAS-No. 52829-07-9) [0239] R2: Reference 2 is Tinuvin® 5866 (from BASF), which is a blend of an UV absorber and a basic HALS, wherein the HALS component bis(1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate is included.

Filler Component F:

[0240] F1: Hakuenka® CCR-S10, precipitated calcium carbonate coated with fatty acids

Further Components G:

[0241] G1: Plasticizer, Mesamoll®, C.sub.10-C.sub.21 alkane sulfonic acid phenylester, [0242] G2: Adhesion promoter, 3-aminopropyltrimethoxysilan (Dynasylan® AMMO, Degussa Evonik); [0243] G3: Catalyst TIB KAT 223, Dioctyltindiketanoat, [0244] G4: Moisture scavenger, vinyltrimethoxysilan (Dynasylan® VTMO, Degussa Evonik);

[0245] In a 150 ml speed mixer cup (PP 250 ml), 52.0 g of filler F1 were added to 29.2 g of polymer SMP1 and 14.6 g of plasticizer G1. The mixture was stirred in a SpeedMixer DAC 600.1 FVZ at 2300 rpm for 30 seconds at ambient temperature. Components A1, B1 and C1, in amounts according to tables 3, 4 and 5 below, were added to the resulting mixture and stirred for further 60 seconds at 2300 rpm. Finally, 0.9 g of adhesion promoter G2, 2.0 g of moisture scavenger G4 and 0.5 g of catalyst G3 were added to the resulting mixture and stirred for additional 30 seconds at 2300 rpm. The reference samples Ref.1 to Ref.6 were prepared accordingly using the reference stabilizers R1 and R2.

[0246] Heat stability, surface cracking resistance and color were determined for each sample using the testing methods as described in example 5 below.

[0247] The following basic formulations as described in table 3 were used:

TABLE-US-00004 TABLE 3 Overview of formulations, all amounts given in g Inventive Comparative Comparative examples examples examples Ex1-Ex15 Ref1-Ref4 Ref5-Ref6 SMP1 29.2 29.2 29.2 F1 52.0 52.0 52.0 G1 14.6 14.6 14.6 G2 0.9 0.9 0.9 G4 2.0 2.0 2.0 G3 0.5 0.5 0.5 S A1 0.3-0.5 B1 0.3-0.5 C1 0.0-0.2 A2 0.4 B2 0.4 R2 0.8-1.2

[0248] The test results are summarized in the following tables 4 and 5.

[0249] It is demonstrated that heat stability and surface cracking resistance of reference materials (Ref1 to Ref 6) is met or improved using the inventive combination of UV absorber A1, HALS B1 and phenolic antioxidant C1. Ordinary, the inventive stabilizer combination shows 44% greater heat stability and 67% greater surface cracking resistance compared to the reference examples.

[0250] Further, the experimental data shows (for example as shown in FIG. 4) that the addition of the phenolic antioxidant C1 results in a significant synergistically improvement of heat stability and surface cracking resistance.

[0251] The initial Yellowness Index (YI at 0 hours) has no significant variation among the samples. Average YI of 6.29 is in line with the results of Ref1-Ref4 and lower than results of Ref5 to Ref6.

TABLE-US-00005 TABLE 4 Experimental plan and results (inventive examples) Heat Stabilizer Stability UV A1 B1 C1 110° C. Stability YI dE dL* da* db* No. [%] [%] [%] [hours] [hours] 0 h after 1000 h Ex1 0.4 0.5 0 1776 1000 6.61 1.21 −0.16 0.52 −1.08 Ex2 0.5 0.4 0 1608 1000 6.19 1.18 −0.44 0.50 −0.97 Ex3 0.5 0.5 0.1 2976 2500 6.14 0.59 −0.45 0.26 0.26 Ex4 0.3 0.5 0.1 2184 1500 5.86 0.32 −0.10 0.26 −0.14 Ex5 0.3 0.3 0.1 1776 1500 5.96 0.47 −0.40 0.21 −0.11 Ex6 0.4 0.5 0.2 2880 2500 6.76 0.38 −0.25 0.28 −0.05 Ex7 0.5 0.4 0.2 2784 2000 6.44 0.97 −0.66 0.23 −0.68 Ex8 0.5 0.3 0.1 2352 2000 6.58 0.84 −0.82 0.12 −0.16 Ex9 0.4 0.4 0.1 2616 2000 6.11 0.21 −0.10 0.16 −0.13 Ex10 0.4 0.4 0.1 2616 2000 6.33 0.64 −0.60 0.17 −0.11 Ex 11 0.3 0.4 0.2 2880 2000 6.24 0.78 −0.53 0.26 0.51 Ex12 0.4 0.4 0.1 2616 2000 6.30 0.77 −0.70 0.29 −0.99 Ex13 0.3 0.4 0 1512 500 6.56 1.17 −0.60 0.38 −0.93 Ex14 0.4 0.3 0 1440 500 5.76 1.19 −0.94 0.47 −0.56 Ex15 0.4 0.3 0.2 2808 2500 6.57 0.83 −0.27 0.20 0.75 (% is % by weight)

TABLE-US-00006 TABLE 5 Experimental plan and results (comparative examples) Heat Stabilizer Stability UV A2 B2 R2 110° C. Stability YI dE dL* da* db* No. [%] [%] [%] [hours] [hours] 0 h after 1000 h Ref1 0 0 0.8 1776 1000 6.37 1.24 −0.73 0.48 −0.89 Ref2 0 0 1.0 1944 1500 6.29 1.29 −0.16 0.56 −1.16 Ref3 0 0 1.0 1944 1500 6.52 1.30 −0.39 0.50 −1.14 Ref4 0 0 1.2 1944 1500 5.99 1.05 −0.27 0.42 −0.92 Ref5 0.4 0.4 0 1776 1500 8.42 1.02 −0.01 0.37 −0.95 Ref6 0.4 0.4 0 1800 1500 8.71 1.09 −0.09 0.36 −1.03 (% is % by weight)

[0252] The test plan and the analysis of the test results were carried out using statistical models using analysis of variance (ANOVA):

[0253] FIG. 1 shows the variation of the heat stability as a function of the concentration of the phenolic antioxidant C1, wherein the lines are model predictions.

[0254] FIG. 2 shows the variation of heat stability as a function of the concentration of HALS component B1 and UV absorber A1, at a constant C1 content of 0.1%.

[0255] FIG. 3 shows the correlation between surface cracking resistance and heat stability. Points are given for different concentration of phenolic antioxidant C1, i.e. 0% square (□); 0.1% lozenge (⋄) and 0.2% triangle (Δ).

[0256] FIG. 4 shows the variation of surface cracking as a function of the concentration of UV absorber A1 and phenolic antioxidant C1.

[0257] The statistical significance of the content of the stabilizer components A1, B1 and C1 was analyzed via ANOVA. The results were as summarized in the following: [0258] The concentration of stabilizer component C1 has a strong effect on heat resistance (p<0.0001), wherein this tends to level out above concentrations of C1 above 0.2% by weight, preferably 0.1% by weight. The stabilizer component A1 (p=0.0501) and stabilizer component B1 (p=0.0410) show a comparable statistically relevant effect on heat resistance. [0259] The stabilizer component C1 has a strong (quadratic) effect on surface cracking resistance (UV stability), wherein this is levelling out at higher concentrations. The stabilizer component A1 has statistically relevant effect (p=0.0018) on surface cracking resistance (UV stability), the stabilizer component B1 does not have a statistically relevant effect (p=0.1759). [0260] dE has a significant model which depend mainly on C1 (RSquared 0.672). [0261] There is a strong correlation (0.95) between surface cracking and heat stability. [0262] The concentration of the phenolic antioxidant C1 is one important factor in the stabilization of the systems, in particular for the improvement of the surface cracking resistance.

[0263] Further, it was surprisingly found that the chemical nature of the phenolic antioxidant is important and that an advantageous synergistic combination is achieved using the phenolic antioxidant C1 in combination with the inventive stabilizer components A and B, in particular A1 and B1.

3. Preparation and Testing of SMP Test Samples (Impact of Antioxidant C)

[0264] SMP test samples were prepared based on the components and methods used in example 2. Heat stability, surface cracking resistance and color were determined for each sample using the testing methods as described in example 5. The formulations were based on example Ex4 in table 4 above and are given as follows (all amounts in g):

TABLE-US-00007 Examples Ex4′-Ex4e [g] SMP1 29.2 F1 52.0 G1 14.6 G2 0.9 G4 2.0 G3 0.5 A 0.3 B 0.5 C 0.1

[0265] The components SMP1, F1, G1, G2, G4, and G3 are as described above. The following stabilizers A, B, and C are used: [0266] A1: UV absorber, 2-Ethyl-2′-ethoxy-oxalanilide (CAS-No. 23949-66-8); [0267] B1: HALS, reaction product of 2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro-20-(2,3-epoxi-propyl)dispiro-(5.1.11.2)-heneicosane-21-one and epichlorohydrin, (Hostavin® N30 from Clariant); [0268] B3: Tinuvin®622 (BASF SE), Poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol-alt-1,4-butanedioic acid) (CAS-No. 65447-77-0); [0269] B4: Tinuvin® 44 (BASF SE), Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate (CAS-No. 63843-89-0); [0270] C1: Phenolic antioxidant, bis-(3,3-bis-(4′-hydroxy-3′-tert. butylphenyl)butanic acid)-glycolester (CAS-No. 32509-66-3); [0271] C2: Hostanox® P-EPQ from Clariant, multicomponent system with tetrakis(2,4-di-tert-butylphenyl)-1,1-biphenyl-4,4′-diylbisphosphonite (CAS 38613-77-3) as main component; [0272] C3: Irganox®1010, Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), CAS-No. 6683-19-8; [0273] C4: Tinuvin®144 (BASF SE), Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate (CAS-No. 63843-89-0).

[0274] The comparative stabilizer Tinuvin®144 (BASF SE) includes phenolic groups as well as hindered amine groups and was used as comparative phenolic antioxidant C4 and as HALS component B4. The SMP formulations and test results are summarized in the following tables 6 and 7.

TABLE-US-00008 TABLE 6 SMP Formulations Ex4′-Ex4e Amount stabilizer Stabilizer wt.-% No. A B C A B C Ex4′ A1 B1 C1 0.3 0.5 0.1 Ex4a* A1 B1 C2 0.3 0.5 0.1 Ex4b* A1 B1 C3 0.3 0.5 0.1 Ex4c* A1 B1 C4 0.3 0.5 0.1 Ex4d A1 B4 C1 0.3 0.5 0.1 Ex4e A1 B3 C1 0.3 0.5 0.1 (*comparative examples)

TABLE-US-00009 TABLE 7 Results Ex4′-Ex4e Heat Stability UV Stabilizer 110° C. Stability YI dE dL* da* db* No. A B C [hours] [hours] 0 h after 1000 h Ex4′ A1 B1 C1 >1950 >1600 6.86 2.00 −1.96 0.34 −0.26 Ex4a* A1 B1 C2 1608 1000 7.16 3.10 2.85 0.47 −1.12 Ex4b* A1 B1 C3 1680 1000 7.09 3.07 −2.86 0.39 −1.02 Ex4c* A1 B1 C4 >1950 1500 7.37 1.63 −1.03 0.50 −1.15 Ex4d A1 B4 C1 >1950 >1600 6.66 1.09 −0.77 0.66 −0.40 Ex4e A1 B3 C1 1940 1000 6.78 2.89 −2.86 0.32 −0.23

[0275] The important impact of the chemical nature of the phenolic antioxidant is substantiated by the examples shown above. It was found that an advantageous synergistic combination is achieved using the phenolic antioxidant C1 in combination with the inventive stabilizer components A and B, in particular A1 and B1. The advantageous effect, regarding improved heat stability and improved surface cracking resistance (UV stability) is not achieved using another antioxidant, e.g. comparative stabilizers C2, C3 or C4.

4. Comparative Data

[0276] The following polymer compositions were prepared as described in example 2. The basic formulation is described in table 8:

TABLE-US-00010 TABLE 8 Basic formulation of Ex16-Ex28 (amounts given in % by weight) Compound Commercial name Amount P SMP2 Silyl-modified Geniosil STP-E35, 25.0 polymer (Wacker) F1 Precipitated Hakuenka ® CCR- 21.4 Filler calcium S10 (Shiraishi- carbonate Omya) F2 Grounded Omyabond 520-OM 21.4 Filler calcium (Omya) carbonate G5 Plasticizer PPG 2000 (VWR) 25.0 G2 Adhesion Dynasylan ® AMMO, 1.0 promoter (Degussa Evonik) G4 Moisture Dynasylan ® VTMO 2.0 scavenger (Degussa Evonik) G5 Catalyst TIB KAT 216 0.2 G6 Fumed silica HDK H18 (Wacker) 2.0 S A UV absorber 0.5 B HALS 0.5 C Antioxidant 1.0 Total 100

[0277] The following stabilizer components A, B and C were used:

Stabilizers S:

[0278] A1: UV absorber, 2-Ethyl-2′-ethoxy-oxalanilide (CAS-No. 23949-66-8); [0279] A2: UV absorber, 2-(2′-Hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzortriazole (CAS-No. 3896-11-5); [0280] B1: HALS, reaction product of 2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro-20-(2,3-epoxi-propyl)dispiro-(5.1.11.2)-heneicosane-21-one and epichlorohydrin, (Hostavin® N30 from Clariant); [0281] B5: HALS, mixture of -Beta-alanine, N-(2,2,6,6-tetramethyl-4-piperidinyl)-, dodecyl & tetradecyl; [0282] B6: HALS, propanedioic acid, [(4-methoxyphenyl)-methylene]-, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)ester, CAS-No 147783-69-5; [0283] B7: HALS, N-Acetyl-3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione; [0284] B8: HALS, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione; [0285] C1: Phenolic antioxidant, bis-(3,3-bis-(4′-hydroxy-3′-tert. butylphenyl)butanic acid)-glycolester (CAS-No. 32509-66-3); [0286] C2: Hostanox® P-EPQ from Clariant, multicomponent system with tetrakis(2,4-di-tert-butylphenyl)-1,1-biphenyl-4,4′-diylbisphosphonite (CAS 38613-77-3) as main component.

[0287] Reference 2 (Ref. 2) (Tinuvin® 5866) was used as comparative material for component A, B and C as well.

[0288] The additives, as mentioned above, are used in the concentrations (% by weight) as given in tables 9 and 11. Heat stability (at 110° C. or at 180° C.) and surface cracking resistance were determined for each sample using the testing methods as described below in example 5. The test results are summarized in the following tables 10 and 12.

TABLE-US-00011 TABLE 9 Experiments Ex16-Ex26-Variation in stabilizers A and B (amounts given in % by weight) Stabilizer Amount No. A B C A B C Ex16 A1 B2 C2 1 0.6 0.4 Ex17 A1 B2 C2 1 0.6 0.4 Ex18 A1 B3 C2 1 0.6 0.4 Ex19 A1 B4 C2 1 0.6 0.4 Ex20 A1 B5 C2 1 0.6 0.4 Ex21 A2 B1 C2 1.2 0.4 0.4 Ex22 A1 B1 C2 1.2 0.4 0.4 Ex23 A1 B1 C2 1 0.6 0.4 Ex24 A1 B1 none 1.2 0.8 0 Ex25 Ref.2 2 Ex26 none none none 0 0 0

TABLE-US-00012 TABLE 10 Results Ex16-Ex25-Variation in stabilizers A and B Heat stability at Heat stability at 110° C. 180° C. UV stability No. [hours] [hours] [hours] Ex16 480 2.5 800 Ex17 480 3.0 900 Ex18 168 2.0 1000 Ex19 24 2.0 1000 Ex20 960 2.5 1100 Ex21 672 2.5 1000 Ex22 960 2.0 1100 Ex23 1200 2.0 1100 Ex24 1200 2.0 1500 Ex25 960 6.7 1300 Ex26 24 1.0 50

TABLE-US-00013 TABLE 11 Experiments Ex26-Ex28-Variation in stabilizer C (amounts given in % by weight) No. Stabilizer Amount Ex26 none none none 0 0 0 Ex27 none none C2 0 0 0.5 Ex28 none none C1 0 0 0.5 Ex25 Ref.2 2

TABLE-US-00014 TABLE 12 Results Ex26-Ex28-Variation in stabilizer C Heat stability at 180° C. No. hours Ex26 1.0 Ex27 2.0 Ex28 10.0 Ex25 6.7

[0289] The sum of all stabilizers A+B+C is 2% by weight in each of the experiments Ex16 to Ex25. It is demonstrated that the heat stability at 110° C. of materials based on UV absorber A1 in combination with HALS B1 is higher than other combination of UV stabilizer and HALS. For example, the heat stability at 110° C. of Ex23 (based on UV absorber A1 in combination with HALS B1) is higher when compared to the material of Ex16-20 (based on combinations with different HALS, i.e. B5, B6, B7, B8). For example, the heat stability at 110° C. of Ex22 (based on UV absorber A1 in combination with HALS B1) is higher when compared to the material of Ex21 (based on different UV absorber A2). Further the heat stability at 110° C. and the UV stability of Ex24 (using UV absorber A1 in combination with HALS B1) is better when compared to the reference material Ex25 (using reference 2, Tinuvin® 5866).

[0290] It is further demonstrated that the phosphonite antioxidant C2 in combination of A1 and B1 does not result in improved heat stability at 110° C. or improved UV stability (comparing examples Ex24 and Ex22).

[0291] The heat stability at 180° C. of SMP-materials based on antioxidant C1 (Ex28) is significantly higher than of materials based on antioxidant C2 (Ex27) and reference material Ex25 (using reference 2, Tinuvin® 5866).

5. Testing Methods

Heat Stability

[0292] The heat stability of the SMP samples, prepared as described above, was tested by the following procedure. 25×25×2 mm specimens were cut from the cured film and placed on a cardboard panel, to ensure a homogenous temperature. The panel was placed in the central section of an oven, preheated at a set temperature of either 110° C. (Memmert UF30 ventilated oven) or at 180° C. (non-ventilated oven). The oven was operated in laboratory environment at controlled temperature of 23±1° C. and controlled humidity of 50±5%. The samples were checked periodically. At 110° C. the maximum interval between observations was 100 hours. At 180° C. the maximum interval between observations was 1 hours. A sample was classified as “failed” at the first signs of cracking and removed from the oven. The heat stability is given in hours until failure, as reported in the tables above.

Surface Cracking Resistance

[0293] The UV stability (surface cracking resistance) of the SMP samples prepared as described above was determined using weather-o-meter (WoM) according to ISO 4892-2 E2013 wet/dry. The cured samples were exposed to UV radiations with cycles of 102 minutes dry period followed by 18 minutes of water spray with fresh demineralized water. The radiation intensity was 60 W/m.sup.2 (300-400 nm). The tests were carried out in accordance with ISO 4892-2 E2013 at 50% relative humidity, and a temperature of 65° C.+/−3° C. (black standard).

[0294] The samples were checked every 500 hours, till 2000 hours including visual check of surface cracks and color measurement. A sample was recorded as “failed” when surface crack was visible. The surface cracking resistance is given in hours until failure. Samples with only small cracks at 2000 hours were assigned a “failure” of 2500 hours.

Yellowing

[0295] The Yellowness Index (YI) of the test samples were measured without thermal treatment according to ASTM E313. Furthermore, color measurement based on CIE color system was done before and after 1000 h of thermal exposure at 110° C. in a ventilated oven. CIE LAB values L*, a* and b* as well as dE, were determined using a Spectrophotometer Minolta CM-3600d, calibration with Zero box and white reference plate, wherein L*defines lightness, a* denotes the red/green value and b* the yellow/blue value. The differences of CIE LAB values before and after thermal treatment are given in the tables above.

Weight Median Particle Diameter d.SUB.50 .Value

[0296] Throughout the present invention, d.sub.50 is the weight median particle diameter by weight, for all particulate materials other than surface-reacted calcium carbonate i.e. representing the particle size so that 50 wt.-% of the particles are coarser or finer.

[0297] The weight median particle diameter was measured according to the sedimentation method. The sedimentation method is an analysis of sedimentation behaviour in a gravimetric field. The measurement is made with a Sedigraph™ 5100 of Micromeritics Instrument Corporation. The method and the instrument are known to the skilled person and are commonly used to determine grain size of fillers and pigments. The measurement is carried out in an aqueous solution of 0.1 wt.-% Na.sub.4P.sub.2O.sub.7. The samples were dispersed using a high speed stirrer and supersonic.

Specific Surface Area (BET)

[0298] The specific surface area was measured using nitrogen and the BET method according to ISO 9277:2010.