MULTILAYER COATING SYSTEMS OBTAINED FROM BLOCK COPOLYMER CONTAINING TOPCOAT COMPOSITIONS

Abstract

Disclosed herein is a multilayer coating system present on a substrate and including at least two coating layers L1 and L2 different from one another, namely a first coating layer L1 applied over at least a portion of the substrate, and a second topcoat layer L2 applied over the first coating layer L1, where the topcoat layer L2 is formed from a coating composition including at least one block copolymer containing a backbone and at least two blocks B1 and B2 and side chains S1 and S2 including different polymeric moieties M1 and M2. Also disclosed herein are a method of preparing said multilayer coating system, a coated substrate obtainable therefrom, and a method of using a coating composition including the block copolymer for improving, in particular for increasing, the chromaticity of the multilayer coating system.

Claims

1. A multilayer coating system present on an optionally pre-coated substrate and comprising at least two coating layers L1 and L2 different from one another, the multilayer coating system comprising: a first coating layer L1 applied over at least a portion of an optionally pre-coated substrate, and a topcoat layer as second coating layer L2 applied over the first coating layer L1, wherein the topcoat layer L2 is formed from a coating composition comprising at least one block copolymer containing a backbone and at least two blocks B1 and B2 different from one another, wherein block B1 comprises at least one kind of side chains S1 attached to the backbone and block B2 comprises at least one kind of side chains S2 attached to the backbone, which are different from side chains S1, wherein each of side chains S1 comprises at least one polymeric moiety M1 selected from the group consisting of polyester, polyether and poly(meth)acrylate moieties, and each of side chains S2 comprises at least one polymeric moiety M2 different from polymeric moiety M1 and selected from the group consisting of polyester, poly(meth)acrylate, polyether, polysiloxane and polystyrene moieties.

2. The multilayer coating system according to claim 1, wherein the first coating layer L1 is a pigmented coating layer.

3. The multilayer coating system according to claim 1, wherein the first coating layer L1 is capable of absorbing at least those wavelengths that are not reflected by the topcoat layer L2.

4. The multilayer coating system according to claim 1, wherein the topcoat layer L2 is a clearcoat layer formed from a coating composition, which is a clearcoat composition.

5. The multilayer coating system according to claim 1, wherein the first and the second coating layers L1 and L2 are positioned adjacently to each other.

6. The multilayer coating system according to claim 1, wherein the multilayer coating system has an C*average value of at least 40 the C*average value being the sum of C*-values (chroma values according to the L*C*h color model) measured at angles of 15?, 45? and 110?, divided by three.

7. The multilayer coating system according to claim 1, wherein it is obtainable by a method, according to which at least the applied coating composition comprising the at least one block copolymer, which is used for preparing the topcoat layer L2, is cured or dried to obtain the topcoat layer L2 of the multilayer coating system.

8. The multilayer coating system according to claim 1, wherein the backbone of the copolymer comprises ethylenically unsaturated carbon-carbon double bonds.

9. The multilayer coating system according to claim 1, wherein each of side chains Si of the first block B1 of the copolymer comprises at least one polymeric moiety M1.

10. The multilayer coating system according to claim 1, wherein the at least one copolymer has a number average molecular weight (Mn) in a range of from 450 to 3000 kDa.

11. The multilayer coating system according to claim 1, wherein the first block B1 of the copolymer comprises at least one structural unit SU1a and optionally at least one structural unit SU1b, wherein structural unit SU1a is represented by at least one of part structures PS1a-1 and PS1a-2, and wherein optionally present structural unit SU1b is represented by part structure PS1b. ##STR00004## wherein independently of one another parameter x is in a range of from 1 to 1000, parameter a is in a range of from 0 to 1000, the relative ratio of parameters x:a is in a range of from 2:0 to 1:3, Mx, J.sub.1 and G represent independently of one another CH.sub.2 or C?O, Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl residue, Rx represents side chain S1 comprising polymeric moiety M1and R.sub.1 represents a C.sub.1-C.sub.6-alkyl residue, and the second block B2 of the copolymer comprises at least one structural unit SU2a and optionally at least one structural unit SU2b, wherein structural unit SU2a is represented by at least one of part structures PS2a-1 and PS2a-2, and wherein optionally present structural unit SU2b is represented by part structure PS2b, ##STR00005## wherein independently of one another parameter y is in a range of from 1 to 1000, parameter b is in a range of from 0 to 1000, the relative ratio of parameters y:b is in a range of from 2:0 to 1:3, My, J.sub.2 and G represent independently of one another CH.sub.2 or C?O, Q represents a divalent alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl residue, Ry represents side chain S2 comprising polymeric moiety M2, and R.sub.2 represents a C.sub.1-C.sub.6-alkyl residue.

12. The multilayer coating system according to claim 1, wherein the at least one copolymer is present in the coating composition used for preparing the topcoat layer L2, in an amount in the range of from 10 to 100 wt.-%, based in each case on the total solid content of the coating composition.

13. The multilayer coating system according to claim 1, wherein the coating composition used for preparing the topcoat layer L2 further comprises at least one homopolymer.

14. The multilayer coating system according to claim 1, wherein the coating composition used for preparing the topcoat layer L2 comprises at least one further resin.

15. A method for preparing the multilayer coating system according to claim 1, comprising (1) applying a basecoat composition to at least a portion of an optionally pre-coated substrate and forming a first coating film on at least the portion of the optionally pre-coated substrate, (2) applying a topcoat composition comprising the at least one block copolymer and being different from the basecoat composition applied in step (1) to the first coating film present on the substrate obtained after step (1) and forming a second coating film and (3) curing or drying at least the second coating film applied in step (2) and optionally also the first coating film applied in step (1) in case said first coating film was not cured or dried prior to performing of step (2) to obtain the multilayer coating system comprising at least the first and the second coating layers L1 and L2.

16. A coated substrate obtained by the method according to claim 15.

17. A method of using a coating composition, comprising at least one block copolymer, the method comprising using the coating composition for improving, the chromaticity of the multilayer coating system according to claim 1.

18. The multilayer coating system according to claim 1, wherein the first coating layer L1 is formed from a pigmented coating composition.

19. The multilayer coating system according to claim 1, wherein the topcoat layer L2 is a clearcoat layer formed from a coating composition, which is a solventborne clearcoat composition.

20. The multilayer coating system according to claim 1, wherein the topcoat layer L2 is the outermost coating layer of the multilayer coating system.

Description

EXAMPLES

[0163] The following examples further illustrate the invention but are not to be construed as limiting its scope. Pbw means parts by weight. If not defined otherwise, parts means parts by weight.

[0164] 1. Preparation of an Inventively Used Copolymer

[0165] To a 2000 mL vessel under inert atmosphere, a norbornene functionalized polyactide macromonomer (PLA-MM) (29.14 mmol, having an M.sub.n of 3.26 kDa) and d,x-DME (dimethyl-5-norbornene-2,3-dicarboxylate with d=endo and x=exo) were added in equimolar amounts in dichloromethane. PLA-MM was prepared prior via a tin-catalyzed ring opening polymerization of lactide using a norbornene alcohol initiator yielding an OH-functional and norbornene functionalized polylactide macromonomer PLA-MM. PLA-MM was prepared in the general manner as described within the supporting information of B. R. Sveinbj?rnsson et al., PNAS 2012, 109 (36), p. 14332-14336. A bis-bipyridine ruthenium catalyst was then rapidly added to the mixture of PLA-MM and d,x-DME to initiate copolymerization, targeting PLA.sub.100-r-DME.sub.100. r means that the two monomeric units PLA and DME are arranged randomly. The mixture was stirred for 45 minutes at room temperature (first block mixture). In a separate vessel under inert atmosphere, a solution of a norbornene functionalized polystyrene macromonomer (PS-MM; having an M.sub.n of 3.83 kDa) and d,x-DIPE (diisopropyl-5-norbornene-2,3-dicarboxylate with d=endo and x=exo) was prepared in dichloromethane (second block mixture). PS-MM was prepared prior in two steps in the general manner as described within example 2 of WO 2020/180427 A1: an OH-functional polymerized precursor of PS-MM was prepared by polymerization of styrene in toluene and sec-butyl lithium as initiator. After chain termination by addition of propylene oxide, followed by methanol, quenching as performed. Then, the terminal OH-group of the formed precursor was transformed into an ester bond via a reaction with a norbornene carboxylic acid to yield PS-MM. The solution of PS-MM and d,-DIPE was added to the first block reaction mixture rapidly. The two monomeric units PS and DIPE are arranged randomly within the formed second block of the copolymer. The resulting mixture was allowed to stir at room temperature for an additional 4 h and then quenched by adding ethyl vinyl ether. Then, quenched catalyst was scavenged using functionalized silica gel absorbent and it was stirred for about 4 h. The mixture was filtered and the solution concentrated under reduced pressure. The solid copolymer was obtained after the solvent is removed. It was dried in a vacuum oven for 4 hours at 75 C. to remove residual solvent. The product obtained (BBCP1) was used in this form.

[0166] BBCP1 had a number average molecular weight (M e) of 788.3 kDa and a weight average molecular weight (M w) of 865.7 kDa. The polydispersity index (PDI) was 1.10 accordingly.

[0167] 2. Preparation of BBCP1 Containing Coating Compositions 2.1 Topcoat Compositions TC1 to TC5

[0168] TC1 was obtained by preparing a solution of 1.80 g BBCP1, 0.60 g of a polystyrene homopolymer (PS-HP), 0.60 g of a polylactide homopolymer (PLA-HP) and 7 g n-butyl acetate. The relative weight ratio of BBCP1 solids to combined solids of PS-HP and PLA-HP in TC1 was 60:40.

[0169] TC2 was obtained by preparing a solution of 1.65 g BBCP1, 0.68 g of a polystyrene homopolymer (PS-HP), 0.68 g of a polylactide homopolymer (PLA-HP) and 7 g n-butyl acetate. The relative weight ratio of BBCP1 solids to combined solids of PS-HP and PLA-HP in TC2 was 55:45.

[0170] TC3 was obtained by preparing a solution of 1.50 g BBCP1, 0.75 g of a polystyrene homopolymer (PS-HP), 0.75 g of a polylactide homopolymer (PLA-HP) and 7 g n-butyl acetate. The relative weight ratio of BBCP1 solids to combined solids of PS-HP and PLA-HP in TC3 was 50:50.

[0171] TC4 was obtained by preparing a solution of 1.38 g BBCP1, 0.81 g of a polystyrene homopolymer (PS-HP), 0.81 g of a polylactide homopolymer (PLA-HP) and 7 g n-butyl acetate. BC1 had a solids content of 30 wt.-%. The relative weight ratio of BBCP1 solids to combined solids of PS-HP and PLA-HP in TC4 was 46:54.

[0172] TC5 was obtained by preparing a solution of 1.20 g BBCP1, 0.90 g of a polystyrene homopolymer (PS-HP), 0.90 g of a polylactide homopolymer (PLA-HP) and 7 g n-butyl acetate. The relative weight ratio of BBCP1 solids to combined solids of PS-HP and PLA-HP in TC5 was 40:60.

[0173] The polystyrene homopolymer (PS-HP) used had a M.sub.n of 3.95 kDa. The polylactide homopolymer (PLA-HP) used had a M.sub.n of 4.26 kDa.

[0174] 2.2 Topcoat Compositions TC1a to TC5a as Well as TC4a2

[0175] Diluted compositions of each of TC1 to TC5 were prepared. TC1a was obtained by mixing 85 pbw (parts by weight) of TC1 with 15 pbw of n-butyl acetate. TC2a was obtained by mixing 85 pbw (parts by weight) of TC2 with 15 pbw of n-butyl acetate. TC3a was obtained by mixing 85 pbw (parts by weight) of TC3 with 15 pbw of n-butyl acetate. TC4a was obtained by mixing 85 pbw (parts by weight) of TC4 with 15 pbw of n-butyl acetate. TC5a was obtained by mixing 85 pbw (parts by weight) of TC5 with 15 pbw of n-butyl acetate.

[0176] A further diluted composition of TC4 was prepared. TC4a2 was obtained by mixing 90 pbw (parts by weight) of TC4 with 10 pbw of n-butyl acetate.

[0177] 2.3 Topcoat Compositions TC1b to TC5b

[0178] Topcoat composition TC1b was obtained by mixing 85 pbw (parts by weight) of TC1 with 15 pbw of R10CG392A. Topcoat composition TC2b was obtained by mixing 85 pbw (parts by weight) of TC2 with 15 pbw of R10CG392A. Topcoat composition TC3b was obtained by mixing 85 pbw (parts by weight) of TC3 with 15 pbw of R10CG392A. Topcoat composition TC4b was obtained by mixing 85 pbw (parts by weight) of TC4 with 15 pbw of R10CG392A. Topcoat composition TC5b was obtained by mixing 85 pbw (parts by weight) of TC5 with 15 pbw of R10CG392A.

[0179] R10CG392A is a commercially available 1K high solids clearcoat composition. R10CG392A was mixed to the respective topcoat in each case under agitation.

[0180] 2.4 Topcoat compositions TC4c95, TC4c90, TC4c85, TC4c80, TC4c75 and TC4c70 Topcoat composition TC4c95 was obtained by mixing 95 pbw (parts by weight) of TC4 with 5 pbw of R10CG392A. Topcoat composition TC4c90 was obtained by mixing 90 pbw (parts by weight) of TC4 with 10 pbw of R10CG392A. Topcoat composition TC4c85 was obtained by mixing 85 pbw (parts by weight) of TC4 with 15 pbw of R10CG392A. Topcoat composition TC4c80 was obtained by mixing 80 pbw (parts by weight) of TC4 with 20 pbw of R10CG392A. Topcoat composition TC4c75 was obtained by mixing 75 pbw (parts by weight) of TC4 with 25 pbw of R10CG392A. Topcoat composition TC4c70 was obtained by mixing 70 pbw (parts by weight) of TC4 with 30 pbw of R10CG392A. Each of the topcoat compositions was prepared by adding R10CG392A to TC4 under agitation.

[0181] 2.5 Topcoat Compositions TC4-CC1, TC4-CC2, TC4-CC3, TC4-CC4 and TC4-CC5

[0182] Topcoat composition TC4-CC1 was obtained by mixing 84.7 pbw (parts by weight) of TC4 with 15.3 pbw of R10CG392D. R10CG392D is a commercially available 1K clearcoat composition. Topcoat composition TC4-CC2 was obtained by mixing 84.4 pbw (parts by weight) of TC4 with 15.6 pbw of R10CG062T. R10CG062T is a commercially available Uregloss CW? 1K clearcoat composition. TC4-CC3 was obtained by mixing 83.9 pbw (parts by weight) of TC4 with 16.1 pbw of E126CG300. E126CG300 is a commercially available Stargloss? 1K clearcoat composition. TC4-CC4 was obtained by mixing 85.4 pbw (parts by weight) of TC4 with 14.6 pbw of a commercially available 2K Progloss? clearcoat composition. Said 2K clearcoat composition has been in turned prepared from mixing 1 pbw of its B-component (N52CG081) to 3.75 pbw of its A-component (E10CG081G). TC4-CC5 was obtained by mixing 84.8 pbw (parts by weight) of TC4 with 15.2 pbw of a commercially available 2K iGloss? clearcoat composition. Said 2K clearcoat composition has been in turned prepared from mixing 1 pbw of its B-component (N52CG500) to 1 pbw of its A-component (E10CG500B).

[0183] 3. Preparation of Multilayer Coating Systems

[0184] A steel panel bearing a cured primer coat was used as substrate. A commercially available back basecoat (E487KU414T Agate Black or E387KU343C Shadow Black) was spray-applied onto the primer coat as a basecoat and cured at about 129? C. (265? F.) for 25 minutes. The dry film layer thickness of the resulting black basecoat was in a range of from about 16.5 ?m to 19.0 ?m (0.65 to 0.75 mils). Then, one of topcoat compositions TC1 to TCS, TC1a to TC5a, TC4a2, TC1b to TC5b, TC4c95 to TC4c70 and TC4-CC1, TC4-CC2 and TC4-CC5 was applied as topcoat composition onto the cured basecoat film by a draw down bar using a 200 pm-gap on a standard draw down bar applicator available from the company Byk in an amount that results in a dry film layer thickness of 27 to 54 ?m later upon baking. After a flash-off at room temperature (23? C.) for up to 10 minutes after application of the topcoat composition it was either baked for 30 minutes at about 140? C. (285? F.) or at about 130? C. (265? F.) or dried at 24? C. (75? F.) for 24 hours.

[0185] 4. Properties of the Substrates Coated with the Multilayer Coating Systems

[0186] Each coated substrate obtained as outlined in item 3. was subjected to an investigation of its color values L* and C* as well as of its R.sub.f- and ?.sub.max-values. Measurement of these values was performed according to the methods disclosed in the Methods section. The measured values are indicated in Tables 1 to 8. C*.sub.average is the C*-value of the sum of the C*-values measured at 15?, 45? and 110?, divided by three.

TABLE-US-00001 TABLE 1 L* and C* as well as R.sub.f- and ?.sub.max- values of coated substrates, part I TC4 TC4 TC4a2 TC4a2 applied applied applied applied as topcoat as topcoat as topcoat as topcoat Baking no yes, at 130? C. no yes, at 130? C. L* (15?) 53.69 35.95 41.76 35.36 L* (45?) 35.39 38.36 29.94 36.8 L* (110?) 40.47 44.72 32.15 37.29 C* (15?) 52.85 60.14 68.23 68.08 C* (45?) 63.07 43.89 58.35 40.01 C* (110?) 51.49 38.49 43.83 33.42 C*.sub.average 55.80 47.51 56.80 47.17 ?.sub.max (15?) 426 456 437 458 ?.sub.max (45?) 461 480 469 485 ?.sub.max (110?) 483 499 485 502 R.sub.f (15?) 0.84 0.49 0.67 0.61 R.sub.f (45?) 0.52 0.36 0.41 0.35 R.sub.f (110?) 0.48 0.34 0.3 0.24

TABLE-US-00002 TABLE 2 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part II - in all cases no baking but only drying was performed TC1 TC2 TC3 TC4 TC5 applied applied applied applied applied as as as as as topcoat topcoat topcoat topcoat topcoat L* (15?) 62.76 63.85 63.38 53.69 46.92 L* (45?) 22.89 19.77 34.52 35.39 41.4 L* (110?) 20.69 16.47 38.9 40.47 42.53 C* (15?) 26.18 26.41 38.56 52.85 62.98 C* (45?) 110.95 94.99 100.05 63.07 49.81 C* (110?) 84.01 60.04 58.65 51.49 50.99 C*.sub.average 73.71 60.48 65.75 55.80 54.59 ?.sub.max (15?) <400 <400 410 426 446 ?.sub.max (45?) 419 427 446 461 486 ?.sub.max (110?) 439 448 468 483 500 R.sub.f (15?) 1.43 1.32 1.15 0.84 0.7 R.sub.f (45?) 0.78 0.51 0.84 0.52 0.45 R.sub.f (110?) 0.39 0.2 0.64 0.48 0.35

TABLE-US-00003 TABLE 3 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part III - in all cases no baking but only drying was performed TC1a TC2a TC3a TC4a TC5a applied as applied as applied as applied as applied as topcoat topcoat topcoat topcoat topcoat L* (15?) 62.04 52.52 55.88 51.13 50.7 L* (45?) 15.33 15.29 22.65 28.24 38.53 L* (110?) 17.36 17.36 23.06 29.38 39.42 C* (15?) 15.21 28.24 42.67 59.16 56.79 C* (45?) 109.61 95.96 85.9 61.05 47.78 C* (110?) 90.97 75.9 54.94 41.89 50.98 C*.sub.average 71.93 66.7 61.17 54.03 51.85 ?.sub.max (15?) <400 <400 409 434 456 ?.sub.max (45?) 418 428 451 468 486 ?.sub.max (110?) 434 442 462 482 507 R.sub.f (15?) 0.98 0.88 0.9 0.8 0.72 R.sub.f (45?) 0.62 0.43 0.44 0.39 0.37 R.sub.f (110?) 0.4 0.29 0.28 0.27 0.28

[0187] The data displayed in Tables 1 to 3 show that applying a BBCP1-containing topcoat onto a cured basecoat film leads to multilayer coating systems having in particular an improved chromaticity (increased chroma C* values). Table 1 shows that good chroma values can be obtained when baking at 130? C. is performed. Even better values are obtained when drying is used. The observation that very good chroma values are obtained when using drying is also evident from Tables 2 and 3. In particular from Table 3 it is evident that additionally a strong red shift to a green appearance is observed, which increases when going from TC1a to TC5a, which is often desirable.

TABLE-US-00004 TABLE 4 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part IV - in all cases baking at 130? C. was performed TC2b TC3b TC4b TC5b applied as applied as applied as applied as topcoat topcoat topcoat topcoat L* (15?) 15.71 19.36 22.23 31.46 L* (45?) 13.46 16.34 22.52 32.66 L* (110?) 19.56 23.16 29.65 39.31 C* (15?) 51.33 59.64 73.05 69.95 C* (45?) 74.94 81.96 72.51 51.46 C* (110?) 80.69 77.35 50.63 40.97 C*.sub.average 69.06 72.98 65.40 54.13 ?.sub.max (15?) <400 <400 420 440 ?.sub.max (45?) 416 424 441 465 ?.sub.max (110?) 438 447 466 489 R.sub.f (15?) 0.5 0.63 0.49 0.51 R.sub.f (45?) 0.37 0.4 0.35 0.36 R.sub.f (110?) 0.39 0.41 0.34 0.33

TABLE-US-00005 TABLE 5 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part V - in all cases baking at 130? C. was performed TC4c95 TC4c90 TC4c85 TC4c80 applied as applied as applied as applied as topcoat topcoat topcoat topcoat L* (15?) 28.06 22.35 22.23 19.83 L* (45?) 25.76 20.48 22.52 19.14 L* (110?) 32.81 26.81 29.65 25.18 C* (15?) 70.82 68.55 73.05 64.82 C* (45?) 72.67 69.38 72.51 75.53 C* (110?) 51.64 46.99 50.63 58.49 C*.sub.average 65.04 61.64 65.40 66.28 ?.sub.max (15?) 421 419 420 <400 ?.sub.max (45?) 448 447 441 430 ?.sub.max (110?) 470 468 466 454 R.sub.f (15?) 0.54 0.45 0.49 0.52 R.sub.f (45?) 0.4 0.31 0.35 0.35 R.sub.f (110?) 0.41 0.29 0.34 0.33

TABLE-US-00006 TABLE 6 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part VI - in all cases baking at 130? C. was performed TC4c75 TC4c70 applied as topcoat applied as topcoat L* (15?) 22.34 32.74 L* (45?) 20.8 19.45 L* (110?) 26.33 23.62 C* (15?) 62.21 38.01 C* (45?) 74.18 62.63 C* (110?) 58.36 55.58 C*.sub.average 64.92 52.07 ?.sub.max (15?) <400 <400 ?.sub.max (45?) 430 417 ?.sub.max (110?) 454 440 R.sub.f (15?) 0.56 0.47 R.sub.f (45?) 0.37 0.31 R.sub.f (110?) 0.33 0.27

[0188] The data displayed in Tables 4 to 6 show that applying a BBCP1-containing topcoat onto a cured basecoat film leads to multilayer coating systems having in particular an improved chromaticity (increased chroma C* values). In particular from Tables 5 and 6 it is evident that a strong blue shift towards UV is observed, which is often desirable.

TABLE-US-00007 TABLE 7 L* and C* as well as R.sub.f- and ?.sub.max-values of coated substrates, part VII - in all cases baking at 140? C. was performed TC4-CC1 TC4-CC2 TC4-CC5 applied as applied as applied as topcoat topcoat topcoat L* (15?) 23.54 23.83 24.98 L* (45?) 19.66 22.89 15.97 L* (110?) 26.29 29.52 22.99 C* (15?) 60.67 71.59 48.68 C* (45?) 79.76 70.5 76.66 C* (110?) 67.09 47.3 69.42 C*.sub.average 69.17 63.13 64.92 ?.sub.max (15?) <400 421 <400 ?.sub.max (45?) 430 447 425 ?.sub.max (110?) 452 468 447 R.sub.f (15?) 0.47 0.48 0.43 R.sub.f (45?) 0.41 0.35 0.35 R.sub.f (110?) 0.39 0.34 0.34

[0189] The data shown in Table 7 demonstrate that color and blue appearance are retained in all cases.