Decorative coatings for plastic substrates

Abstract

The present invention relates to decorative coatings for plastic substrates, the decorative coatings ideally being stable and durable coatings that are spectrally tunable to permit the selection of a variety of appearances, and ideally providing a decorative metal finish. More particularly the present invention provides for a plastic substrate having a decorative coating including a spectrally controlling system and a stress controlling system. The spectrally controlling system includes alternating absorbing layers and transparent layers, and the stress controlling system controls the overall residual stress of the decorative coating to within a desired range. Further provided are methods for applying to a plastic substrate a decorative coating having a spectrally controlling system and a stress controlling system.

Claims

1. A plastic substrate coated with a decorative coating, the decorative coating including a spectrally controlling system and a stress controlling system, the spectrally controlling system being multiple layers and optionally including a protective layer, and the stress controlling system being at least a single layer between the spectrally controlling system and the substrate, wherein the multiple layers of the spectrally controlling system are absorbing layers alternating with transparent layers, the optical thickness of the spectrally controlling system being selected such that the decorative coating achieves a desired optical effect, and wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is compressive when measured in the absence of the optional protective layer, wherein the material for the stress controlling system is selected from the group of materials comprising SiO.sub.x, SiO.sub.xN.sub.y, CrN.sub.x, NbO.sub.x, TaO.sub.x, ZrO.sub.x, where x and y are both between 0.1 and 2.0; and wherein a hardcoating is included between the decorative coating and the substrate.

2. A coated plastic substrate according to claim 1, wherein the absorbing layer is a layer comprising a material, or a blend of materials, having a measured optical extinction coefficient greater than 1 in the spectral range of 400 to 1000 nm.

3. A coated plastic substrate according to claim 2, wherein the absorbing layer material is a metal, a metalloid, a metal alloy or a mixture thereof that has a refractive index such that the sum of the refractive index and the extinction coefficient is greater than 2 and the extinction coefficient itself is greater than 1.

4. A coated plastic substrate according to claim 3, wherein the metal, metalloid or metal alloy for the absorbing layers are selected from the group including: chromium, aluminium, titanium, nickel, molybdenum, zirconium, tungsten, silicon, niobium, tantalum, vanadium, cobalt, manganese, silver, zinc, indium, germanium, tin and mixtures thereof; and an oxide, nitride, boride, fluoride or carbide thereof, and mixtures thereof.

5. A coated plastic substrate according to claim 1, wherein the transparent layer is a layer comprising a material, or a blend of materials, having a measured optical extinction coefficient of less than 1 in the spectral range of 400 to 1000 nm.

6. A coated plastic substrate according to claim 5, wherein the transparent layer material is a metal, a metalloid, a metal alloy or a mixture thereof that has a refractive index such that the sum of the refractive index and the extinction coefficient is less than 3 and the extinction coefficient itself is less than 1.

7. A coated plastic substrate according to claim 6, wherein the metal, metalloid or metal alloy for the transparent layers are selected from the group of metals, metalloids and metal alloys including: boron, silicon, germanium, antimony, tellurium, polonium, niobium, zirconium, magnesium, tin, tantalum, aluminium, chromium, titanium and mixtures thereof; and an oxide, nitride, boride, fluoride or carbide thereof; and mixtures thereof.

8. A coated plastic substrate according to claim 7, wherein the spectrally controlling system is an interference system made up of alternating layers of materials of different refractive indices.

9. A coated plastic substrate according to claim 1, wherein the spectrally controlling system includes a protective layer that is an outermost layer of the spectrally controlling system.

10. A coated plastic substrate according to claim 9, wherein the protective layer is a plasma polymerised hexamethyldisiloxane (HMDSO), a fluoro polymer based coating deposited via evaporation or liquid transfer techniques, or a liquid hard-coating.

11. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is less than 6 MPa when measured in the absence of the optional protective layer.

12. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is less than 63 MPa when measured in the absence of the optional protective layer.

13. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is less than 76 MPa when measured in the absence of the optional protective layer.

14. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is less than 112 MPa when measured in the absence of the optional protective layer.

15. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is greater than 360 MPa when measured in the absence of the optional protective layer.

16. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is greater than 300 MPa when measured in the absence of the optional protective layer.

17. A coated plastic substrate according to claim 1, wherein at least one layer of the stress controlling system has a compressive stress of an amount such that the overall residual stress of the decorative coating is greater than 250 MPa when measured in the absence of the optional protective layer.

18. A coated plastic substrate according to claim 1, wherein the stress controlling system is a single layer of a material which, when deposited, produces a high level of compressive stress.

19. A coated plastic substrate according to claim 1, wherein the stress controlling system is a multilayer system including a compressive or slightly tensile layer deposited on the substrate and a highly compressive layer deposited thereon which, when deposited, produces a high level of compressive stress.

20. A method for applying a decorative coating to a plastic substrate, the decorative coating providing the coated substrate with a desired optical effect, the decorative coating including a spectrally controlling system and a stress controlling system, the spectrally controlling system being multiple layers and optionally including a protective layer, and the stress controlling system being at least a single layer, wherein the multiple layers of the spectrally controlling system are absorbing layers alternating with transparent layers, the method including: determining the desired optical effect; determining a suitable spectrally controlling system that will provide the desired optical effect, with reference to a required optical thickness for the spectrally controlling system; determining a suitable stress controlling system that has a compressive stress of an amount such that the overall residual stress of the decorative coating is compressive when measured in the absence of the optional protective layer; coating the suitable stress controlling system upon the plastic substrate; coating the suitable spectrally controlling system upon the stress controlling system; and thereby forming a coated plastic substrate with the desired colour; wherein the material for the stress controlling system is selected from the group of materials comprising SiO.sub.x, SiO.sub.xN.sub.y, CrN.sub.x, NbO.sub.x, TaO.sub.x, ZrO.sub.x, where x and y are both between 0.1 and 2.0; and wherein a hardcoating is included between the decorative coating and the substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic representation of a coated plastic substrate in accordance with a first preferred embodiment of the present invention, showing the decorative coating in terms of its spectrally controlling system and its stress controlling system; and

(2) FIGS. 2 and 3 are schematic representations of a coated plastic substrate in accordance with a second preferred embodiment of the present invention, representative of the products of Examples 2 and 3 below (showing the hidden 'til lit functionality of the present invention).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) Before providing a more detailed description of various preferred embodiments of the present invention, with reference to various examples, it will be useful to provide some explanation of the role and measurement of stress in multiple layer coatings of the type of the present invention.

(4) In terms of being able to control internal stress parameters, ideally the stress of the entire decorative coating will be controlled, in both magnitude and mode. In this respect, and throughout this specification, the term differential stress is to be taken as meaning the difference in stress between the stress controlling system and the spectrally controlling system, which is representative of the interfacial strain experienced at the interface between them. The term overall residual stress is to be taken as meaning the combined stress of the stress controlling system and the spectrally controlling system, which might thus be regarded as the resultant or absolute stress, as measured in the absence of the optional protective layer.

(5) Many coating layers are tensile at room temperature, which, when applied to plastic substrates, craze when exposed to elevated temperatures such as 85 C. (an auto industry standard). It appears that this is due to the difference in coefficient of thermal expansion (CTE) between such layers (typically being in the range of 710.sup.6 mm/mm/ C. to 2010.sup.6 mm/mm/ C.) and plastic substrates (typically being in the range of 4010.sup.6 mm/mm/ C. to 7010.sup.6 mm/mm/ C.), where the plastic substrate expands significantly more than the layer when heated. By applying a compressive layer with stress of a greater magnitude, a reduction in tensile stress is achieved and this has been found to prevent crazing occurring during exposure to the abovementioned temperatures and thermal shocks.

(6) When coating a plastic substrate with the decorative coating of the present invention, the overall residual stress of the decorative coating (that is the combined stress of the stress controlling system and the spectrally controlling system) is preferably controlled such that it falls within the desired stress window. However, to assist with this control, it is helpful for the stress ranges of the individual layers to be known, so that when they are combined into a decorative coating they result in the desired overall residual stress.

(7) In relation to the distinction between measured stress values and calculated stress values, it will be appreciated that both differential stress and residual stress can be calculated for any given coating system. In this respect, reference is made to the applicant's co-pending International patent publication WO2011/075796 A1, the full content of which is herein incorporated by this reference, for a full description of suitable methods for determining values for differential stress and residual stress and for calculating stress.

EXAMPLES

Example 1Desired Optical EffectPiano Black Spectrally Reflected Appearance with High % T

(8) An injection moulded polycarbonate substrate is first cleaned through a commercial ultrasonic cleaning system with detergent. A final rinse in distilled water is required in a clean (dust free) environment. The substrate is then dip coated in a Momentive PHC-587B at a withdrawal rate of 10 mm/s. A flash-off time of 10 minutes allows solvents to slowly evaporate and the part to be largely tack free. The substrate is then moved to a curing oven for 45 minutes at 130 C. Subsequent coatings are performed within a 48 hour period so as to avoid aging/contamination of the hardcoating.

(9) The substrate is loaded into a batch type vacuum sputter coater, (PylonMET VXL) which consists of a single coating chamber in which the samples are placed, evacuated and coated. Within this chamber the samples were evacuated to a pressure below 810-5 mbar. There was a target to substrate distance of 110 mm and the following were the deposition conditions:

Plasma Pre-Treatment Step

(10) TABLE-US-00001 40 kHz Dual electrode Antenna Power 3 kW Total Gas flow Argon 800 sccm Oxygen 100 sccm RPM 6 Number of rounds 12 Base Pressure (mbar) 8e5 Run Pressure (mbar) 1e2

Stress Controlling System

(11) TABLE-US-00002 Layer 1 Dual rotatable Silicon Target Power 35 kW @ 27 kHz 99.90% Total Gas flow Argon 160 sccm Oxygen 302 sccm RPM 8.4 Number of rounds 36 Base Pressure (mbar) 2e5 Run Pressure (mbar) 2e3 Thickness (nm) 250

Spectrally Controlling System

(12) TABLE-US-00003 Layer 1 Layer 2 Layer 3 Layer 4 Dual rotatable Power 21 kW Power Silicon Target 21 kW 99.90% Chrome Power Power Zirconium Target 9.5 kW 9.5 kW 98.5%/1.5% Total Gas flow Argon Argon 96 sccm Argon Argon 240 sccm Oxygen 202 sccm 240 sccm 96 sccm Oxygen 202 sccm RPM 24 24 24 24 Number of rounds 10 70 5 35 Base Pressure 2e5 2e5 2e5 2e5 (mbar) Run Pressure 2e3 2e3 2e3 2e3 (mbar) Thickness (nm) 9.7 87 6.7 40

Protective Layer

(13) TABLE-US-00004 Layer 1 40 kHz Dual electrode 5 kW Antenna Total Gas flow HMDSO 210 sccm RPM 20 Number of rounds 8 Base Pressure (mbar) 2e5 Run Pressure (mbar) 4e2 Thickness (nm) 8

(14) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 1, 2 and 3 below.

(15) TABLE-US-00005 TABLE 1 Measured stress of the layers Layer Stress Stress controlling system 260 MPa Total residual stress 176 MPa

(16) TABLE-US-00006 TABLE 2 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 12 Scratch resistance (Steel ball test) Rating 2 @ 2N Pass Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass Accelerated UV weathering 2500 kJ/m.sup.2 Pass (SAE J1960)

(17) TABLE-US-00007 TABLE 3 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 4.3% Photopic transmission Y = 13.9% (tinted PMMA 15.03) Reflected colour target on L* = 24.6 transparent substrate - CIE a* = 6 L*a*b* scale measured with b* = 8.6 illuminant A/2 Transmitted colour target on L* = 44 (tinted PMMA 46) transparent substrate - CIE a* = 5.7 (tinted PMMA 4.6) L*a*b* scale measured with b* = 2.6 (tinted PMMA 1.3) illuminant A/2

Example 2Desired Optical EffectBright Chrome with High % T

(18) A process generally as described in Example 1 is employed, with the following alterations.

Spectrally Controlling System

(19) TABLE-US-00008 Layer 1 Layer 2 Material CrZr SiO2 Thickness (nm) 25 15

(20) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 4, 5 and 6 below.

(21) TABLE-US-00009 TABLE 4 Measured stress of the layers Layer Stress Stress controlling system 260 MPa Total residual stress 160 MPa

(22) TABLE-US-00010 TABLE 5 Durability Performance Test Duration Result Abrasion resistance 300 cycles Abrasion (Bayer) ratio = 15 Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass Accelerated UV 2500 kJ/m.sup.2 Pass weathering (SAE J1960)

(23) TABLE-US-00011 TABLE 6 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 55.3% Photopic transmission Y = 7.2% Reflected colour target on transparent L* = 79.2 substrate - CIE L*a*b* scale measured with a* = 0.8 illuminant A/2 b* = 0.72 Transmitted colour target on transparent L* = 32.3 substrate - CIE L*a*b* scale measured with a* = 2.6 illuminant A/2 b* = 3.9

Example 3Desired Optical EffectOpaque Gun Metal (for Illuminated Patterns)

(24) A process generally as described in Example 1 is employed, with the following alterations. However, it should also be noted that the sample is vented between application of the stress controlling system and the spectrally controlling system for metal ablation/removal to enable the illuminated pattern (also referred to as hidden 'til lit) functionality. A schematic representation of a coated substrate in accordance with this embodiment is illustrated in FIG. 2.

Stress Controlling System

(25) TABLE-US-00012 Layer 1 Layer 2 Layer 3 Dual rotatable Power 35 Power 31 Silicon Target kW @ kW @ 99.90% 27 kHz 27 kHz Chrome Zirconium Power 60 Target 98.5%/1.5% kW Total Gas flow Argon 160 Argon 150 Argon 96 sccm sccm sccm Oxygen 302 Nitrogen 90 Oxygen 202 sccm sccm sccm RPM 8.4 24 24 Number of rounds 36 34 3 Base Pressure 2e5 2e5 2e5 (mbar) Run Pressure 2e3 2e3 2e3 (mbar) Thickness (nm) 250 115 15

Spectrally Controlling System

(26) TABLE-US-00013 Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Material SiO2 CrZr SiO2 CrZr SiO2 Thickness (nm) 55 11 69 16.5 17

(27) The measured residual stress of layers was determined and the actual optical measurements obtained. The results are set out in Tables 7 and 8.

(28) TABLE-US-00014 TABLE 7 Measured stress of the layers Layer Stress Stress controlling system 141 MPa Total residual stress 125 MPa

(29) TABLE-US-00015 TABLE 8 Optical Measurement Data - Desired Optical Effect Photopic reflection Y = 35.4% Photopic transmission Y = 0% (10.9% hidden portion) Reflected colour target on L* = 66 transparent substrate - CIE a* = 0.8 L*a*b* scale measured with b* = 1.6 illuminant A/2 Transmitted colour target on L* = 0 (39 hidden portion) transparent substrate - CIE a* = 0 (4.3 hidden portion) L*a*b* scale measured with b* = 0 (1.3 hidden portion) illuminant A/2

Example 4Desired Optical EffectGun Metal (High % T)

(30) A process generally as described in Example 1 is employed, with the following alterations. This product has a similar appearance from the front as in Example 3, however light can be more readily transmitted through it to achieve an added desired optical effect, which might be to cover a display screen or hidden lighting.

Spectrally Controlling System

(31) TABLE-US-00016 Layer 1 Layer 2 Layer 3 Layer 4 Material CrZr SiO2 CrZr SiO2 Thickness (nm) 5 101 9 17

(32) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 9, 10 and 11.

(33) TABLE-US-00017 TABLE 9 Measured stress of the layers Layer Stress Stress controlling system 260 MPa Total residual stress 171 MPa

(34) TABLE-US-00018 TABLE 10 Durability Performance Test Duration Result Abrasion resistance 300 cycles Abrasion (Bayer) ratio = 12 Scratch resistance Rating 2 @ 2N Fail (Steel ball test) Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass Accelerated UV 2500 kJ/m.sup.2 Pass weathering (SAE J1960)

(35) TABLE-US-00019 TABLE 11 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 22.4% Photopic transmission Y = 11% Reflected colour target on transparent L* = 54.4 substrate - CIE L*a*b* scale measured a* = 0.7 with illuminant A/2 b* = 2.5 Transmitted colour target on transparent L* = 40 substrate - CIE L*a*b* scale measured a* = 4.3 with illuminant A/2 b* = 1.3

Example 5Desired Optical EffectBrushed Stainless Steel Effect

(36) This example provides a patterned substrate, together with a hardcoat as a protective layer, with the hardcoat including a matt additive. In this respect, a patterned injection mould tool is used to injection mould a patterned polycarbonate substrate.

(37) The substrate is spray coated in a Momentive PHC-587B with Exxene S-44HRD additive at a 9% wt/vol concentration, which was further diluted by IPA at 30% vol. The thickness was between 0.5 and 4 m as measured in the valleys and peaks respectively of the matt hardcoat by profilometry.

Stress Controlling System

(38) TABLE-US-00020 Layer 1 Dual rotatable Silicon Target Power 35 kW @ 99.90% 27 kHz Total Gas flow Argon 160 sccm Oxygen 302 sccm RPM 8.4 Number of rounds 14 Base Pressure (mbar) 2e5 Run Pressure (mbar) 2e3

Spectrally Controlling System

(39) TABLE-US-00021 Layer 1 Layer 2 Material CrZrN SiO2 Thickness (nm) 30 35

Protective Layer

(40) TABLE-US-00022 Layer 1 Material Hardcoat - Momentive PHC 587B Deposition method Dip Coated and cured at 130 C. Thickness (m) 8

(41) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 12, 13 and 14.

(42) TABLE-US-00023 TABLE 12 Measured stress of the layers Layer Stress Stress controlling system 180 MPa Total residual stress 112 MPa

(43) TABLE-US-00024 TABLE 13 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 9 Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass Accelerated UV weathering 2500 kJ/m.sup.2 Pass (SAE J1960)

(44) TABLE-US-00025 TABLE 14 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = %38.9 Photopic transmission Y = %7.2 (0 actual stainless steel) Reflected colour target on transparent L* = 69 substrate - CIE L*a*b* scale measured a* = 0.9 with illuminant A/2 b* = 4.1 Transmitted colour target on transparent L* = 32 (0 actual stainless steel) substrate - CIE L*a*b* scale measured a* = 1.5 (0 actual stainless steel) with illuminant A/2 b* = 3.2 (0 actual stainless steel)

Example 6Desired Optical EffectSatin Chrome Effect

(45) A process generally as described in Example 1 is employed, with the following alterations. Additionally, a matt additive is included in a hardcoat as a protective layer to achieve a desired diffuse reflection.

Stress Controlling System

(46) TABLE-US-00026 Layer 1 Dual rotatable Silicon Target Power 35 kW @ 27 kHz 99.90% Total Gas flow Argon 160 sccm Oxygen 302 sccm RPM 8.4 Number of rounds 60 Base Pressure (mbar) 2e5 Run Pressure (mbar) 2e3 Thickness (nm) 250

Spectrally Controlling System

(47) TABLE-US-00027 Layer 1 Layer 2 Material CrZr SiO2 Thickness (nm) 25 15

Protective Layer

(48) TABLE-US-00028 Layer 1 Material Momentive PHC-587B + Tospearl (XX) at a 6% wt/vol Deposition Spray Coated and cured at 130 C. Method Thickness (m) 1 to 6

(49) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 15, 16 and 17.

(50) TABLE-US-00029 TABLE 15 Measured stress of the layers Layer Stress Stress controlling system 200 MPa Total residual stress 160 MPa

(51) TABLE-US-00030 TABLE 16 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 9 Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass

(52) TABLE-US-00031 TABLE 17 Optical Measurement Data (Desired Optical Effect) Photopic Total reflection Y = 43.7% Photopic Specular reflection Y = 15.6% Photopic Diffuse reflection Y = 28.1% Photopic transmission Y = 7.2% (0% electroplated satin chrome) Reflected colour target on transparent L* = 72 substrate - CIE L*a*b* scale measured a* = 1.5 with illuminant A/2 b* = 0.7 Transmitted colour target on transparent L* = 32.3 (0 electroplated substrate - CIE L*a*b* scale measured satin chrome) with illuminant A/2 a* = 2.6 (0 electroplated satin chrome) b* = 3.9 (0 electroplated satin chrome)

Example 7Desired Optical EffectBright Chrome with Correct % T (Non-Conducting for IR and rf Transparency)

(53) A process generally as described in Example 1 is employed, with the following alterations. In particular, the samples were loaded into a custom built coating chamber, which consisted of three sputter targets where two of the targets were arranged to achieve co-sputtering.

Stress Controlling System

(54) TABLE-US-00032 Layer 1 Silicon Target Power 1 kW 99.95% Total Gas flow Argon 26 sccm Oxygen 12 sccm RPM 150 Base Pressure 2e5 (mbar) Run Pressure 2e3 (mbar) Thickness (nm) 44

Spectrally Controlling System

(55) TABLE-US-00033 Layer 1 Layer 2 Layer 3 Layer 4 Material Si/Al alloy SiO2 Si/Al Alloy SiO2 Silicon Target Power 1 kW Power 1 kW Power 1 kW Power 1 kW 99.95% Aluminium Power 80 W Power 80 W Target 99.95% Gas flow Argon 26 sccm Argon 26 sccm Argon 26 sccm Argon 26 sccm Oxygen 12 sccm Oxygen 12 sccm Thickness (nm) 21 15 2 m 10

Protective Layer

(56) TABLE-US-00034 Layer 1 Material HMDSO 150 sccm Thickness (nm) 8

(57) The measured residual stress of layers was determined and the actual optical measurements obtained. The results are set out in Tables 18 and 19.

(58) TABLE-US-00035 TABLE 18 Measured stress of the layers Layer Stress Measured Residual Stress 359 MPa

(59) TABLE-US-00036 TABLE 19 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 50.7% Photopic transmission Y = 25.8% Reflected colour target on transparent substrate - L* = 76.4 CIE L*a*b* scale measured with illuminant a* = 1.9 A/2 b* = 1.2 Transmitted colour target on transparent L* = 57.9 substrate - CIE L*a*b* scale measured with a* = 8.0 illuminant A/2 b* = 16.5

Example 8Desired Optical EffectPiano Black with High % T on a Tinted Substrate

(60) A process generally as described in Example 1 is employed, with the following alterations. In particular, a tinted polycarbonate is achieved by mixing clear Lexan LS2 with a prescribed amount of black Lexan 141 to achieve 49% optical transmission prior to injection moulding of the substrate.

Spectrally Controlling System

(61) TABLE-US-00037 Layer 1 Layer 2 Layer 3 Layer 4 Material CrZr SiO2 CrZr SiO2 Thickness 9.7 87 6.7 40 (nm)

Protective Layer

(62) TABLE-US-00038 Layer 1 Material HMDSO 210 sccm Thickness (nm) 8

(63) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 20, 21 and 22.

(64) TABLE-US-00039 TABLE 20 Measured stress of the layers Layer Stress Stress controlling layer 260 MPa Total residual stress 176 MPa

(65) TABLE-US-00040 TABLE 21 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 12 Scratch resistance (Steel ball test) Rating 2 @ 2N Pass Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass Accelerated UV weathering 2500 kJ/m.sup.2 Pass (SAE J1960)

(66) TABLE-US-00041 TABLE 22 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 4.3% Photopic transmission Y = 5.8% Reflected colour target on transparent L* = 24.6 substrate - CIE L*a*b* scale measured with a* = 6 illuminant A/2 b* = 8.6 Transmitted colour target on transparent L* = 29.6 substrate - CIE L*a*b* scale measured with a* = 4.3 illuminant A/2 b* = 4.3

Example 9Desired Optical EffectBlue Chrome

(67) A process generally as described in Example 1 is employed, with the following alterations.

Stress Controlling System

(68) TABLE-US-00042 Layer 1 Dual rotatable Silicon Target Power 21 kW @ 27 kHz 99.90% Total Gas flow Argon 160 sccm Oxygen 302 sccm RPM 24 Number of rounds 21 Base Pressure (mbar) 2e5 Run Pressure (mbar) 2e3 Thickness (nm) 29

Spectrally Controlling System

(69) TABLE-US-00043 Layer 1 Layer 2 Layer 3 Layer 4 Material CrZr SiO2 CrZr SiO2 Thickness (nm) 25 93 12 114

(70) The measured residual stress of layers was determined, the durability performance was tested, and the actual optical measurements obtained. The results are set out in Tables 23, 24 and 25.

(71) TABLE-US-00044 TABLE 23 Measured stress of the layers Layer Stress Stress controlling layer 20 MPa Total residual stress 41 MPa

(72) TABLE-US-00045 TABLE 24 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 16 Scratch resistance (Steel ball Rating 2 @ 2 N Pass test) Salt spray 288 hrs Fail Thermal Shock 200 cycles Pass Dry heat Test 115 C. Fail

(73) TABLE-US-00046 TABLE 25 Optical Measurement Data (Desired Optical Effect) Photopic reflection Y = 49.5% Photopic transmission Y = 0.1% Reflected colour target on transparent L* = 76 substrate - CIE L*a*b* scale measured with a* = 9.2 illuminant A/2 b* = 11.6 Transmitted colour target on transparent L* = 1.0 substrate - CIE L*a*b* scale measured with a* = 0.5 illuminant A/2 b* = 0.7

Example 10Bright Chrome (Substrate with Complex GeometryPlanetary Pylon)

(74) This technique is used to improve the consistency and reproducibility of coatings on substrates with complex geometry. Typically, a substrate will be classified as having a complex geometry if it contains multiple surfaces to be coated and wherein the face of at least two of the surfaces are inflected at angle of greater than 45 degrees relative to each other. For example, the faces of at least two surfaces to be coated may be inflected at an angle of at least 45 degreed past a straight angle to form a face-to-face reflex angle equal to or greater than 225 degrees. Alternatively, the faces of at least two surfaces to be coated may be inflected at least 45 degrees toward each other to form an obtuse or acute face-to-face angle of 135 degrees or less.

(75) The process of coating a substrate with a complex geometry is similar to that described in example 1, with the following alterations.

(76) To get a more uniform deposition onto substrate having a complex geometry, the substrate is loaded into a batch type vacuum sputter coater. The substrate is then rotated about 2 axes in the sputter coater during deposition of the coating. The two axis are parallel with primary axis is at the centre of the chamber and the secondary axis is located between the primary axis and the circumference of the coating drum, generally closer to the circumference than the central axis. The substrate is mounted such that it rotates on the secondary axis and simultaneously the secondary axis rotates around the primary axis. In this manner the rotation of the substrate is much like the rotation of a planet around the sun, hence this technique is also called planetary motion.

(77) By positioning portions of the substrate at differing angles relative to the target throughout the rotation of the substrate, this co-rotation ensures the substrate having a complex geometry does not self-shadow.

(78) The deposition parameters are set out below:

Stress Controlling System

(79) TABLE-US-00047 Stress Controlling Layer 1 Dual rotatable Silicon Target Power 33 kW @ 27 kHz 99.90% Total Gas flow Argon 180 sccm Oxygen 336 sccm RPM 9 Number of rounds 72 Base Pressure (mbar) 5e5 Run Pressure (mbar) 2e3 Thickness (nm) 250

Spectrally Controlling System

(80) TABLE-US-00048 Spectrally Controlling Spectrally Controlling System System Layer 1 Layer 2 Material CrZr SiO2 Chrome Zirconium Power 55 kW Target 98.5%/1.5% Silicon Target 99.9% Power 21 kW Total Gas flow Argon 160 to 145 sccm Argon 96 sccm (45 sec ramp) Oxygen 202 sccm Nitrogen 90 to 20 sccm (45 sec ramp) RPM 10.8 10.5 Number of rounds 6 4 Base Pressure (mbar) 5e5 5e5 Run Pressure (mbar) 2e3 2e3 Thickness (nm) 28 15

Protective Layer

(81) TABLE-US-00049 Protective Layer 1 Material HMDSO 210 sccm RPM 20 Number of rounds 4 Thickness (nm) 8

(82) The measured residual stress of layers was determined and the durability performance was tested. The results are set out in Tables 26, 27 and 28, respectively.

(83) TABLE-US-00050 TABLE 26 Measured stress of the layers Layer Stress Stress controlling layer 144 MPa Total residual stress 76 MPa

(84) TABLE-US-00051 TABLE 27 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 13 Scratch resistance (Steel ball test) Rating 2 @ 2N Pass Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass

(85) TABLE-US-00052 TABLE 28 Optical Measurement Data Photopic reflection Y = 50.9% Photopic transmission Y = 8.8% Reflected colour target on transparent L* = 76.6 substrate - CIE L*a*b* scale measured with a* = 0.5 illuminant A/2 b* = 0.6 Transmitted colour target on transparent L* = 35.6 substrate - CIE L*a*b* scale measured with a* = 2.1 illuminant A/2 b* = 2.5

Example 11Bright Chrome (Zero Optical Transmissionfor Illuminated Patterns)

(86) This technique is used to provide a coating which has zero optical transmission through the coating. Portions of the coating can then be ablated through the full depth of the coating, via techniques such as laser etching, thereby forming patterns which can be illuminated by rear lighting. The zero photopic transmission of the coating prevents light bleed-through of the rear illumination source. A schematic representation of a coated substrate in accordance with this embodiment is illustrated in FIG. 3.

(87) One particular form which this embodiment of the invention may take is the form of a decorative badge for an automobile. Such an embodiment comprises a plastic substrate formed in the desired shape of the badge with a zero optical transmission decorative coating in accordance with the present invention. Portions of the decorative coating are then laser etched or removed to introduce lettering and graphics into the coating which can be emphasized by underlying coloured material. Furthermore, individual highlights can be introduced into the coating in the form of portions of the coating that are completely removed from the substrate via laser ablation, or other acceptable means, to permit controlled light transmission through the coating. The badge can then be backlit to emphasize the highlights and to create a desired visual appeal.

(88) Similar laser etching has been attempted on electroplated plastic substrates. Problematically, the power of the laser needed to remove the relatively thick electroplated layers of copper, nickel and chrome burn and damage the plastic substrate. Advantageously, the coating system of the present invention enables such a decorative article.

(89) A process as described in Example 11 is employed. With the following alterations.

Stress Controlling System

(90) TABLE-US-00053 Stress Controlling Layer 1 Dual rotatable Silicon Power 30 kW @ 27 kHz Target 99.90% Total Gas flow Argon 160 sccm Oxygen 261 sccm RPM 8.4 Number of rounds 65 Base Pressure (mbar) 3e5 Run Pressure (mbar) 2e3 Thickness (nm) 320

Spectrally Controlling System

(91) TABLE-US-00054 Spectrally Spectrally Controlling Controlling System System Layer 1 Layer 2 Material CrZr SiO.sub.2 Chrome Zirconium Target Power 60 kW 98.5%/1.5% Silicon Target 99.90% Power 21 kW Total Gas flow Argon 132 to 240 sccm Argon 96 sccm (75 sec ramp) Oxygen 202 sccm Nitrogen 108 to 0 sccm (75 sec ramp) RPM 6 24 Number of rounds 9 8 Base Pressure (mbar) 3e5 3e5 Run Pressure (mbar) 2e3 2e3 Thickness (nm) 117 25

Protective Layer

(92) TABLE-US-00055 Protective Layer 1 Material HMDSO 210 sccm RPM 20 Number of rounds 8 Thickness (nm) 8 nm

(93) The measured residual stress of layers was determined and the durability performance was tested. The results are set out in Tables 29, 30, and 31, respectively.

(94) TABLE-US-00056 TABLE 29 Measured stress of the layers Layer Stress Stress controlling layer 143 MPa Total residual stress 63.9 MPa

(95) TABLE-US-00057 TABLE 30 Durability Performance Test Duration Result Abrasion resistance (Bayer) 300 cycles Abrasion ratio = 15 Scratch resistance Rating 2 @ 2 N Pass (Steel ball test) Salt spray 288 hrs Pass Thermal Shock 200 cycles Pass Dry heat Test 115 C. Pass

(96) TABLE-US-00058 TABLE 31 Optical Measurement Data Photopic reflection Y = 57.38% Photopic transmission Y = 0.0% Reflected colour target on transparent L* = 80.39 substrate - CIE L*a*b* scale measured a* = 0.56 with illuminant A/2 b* = 0.33

Example 12Bright Chrome (Zero Optical TransmissionLow Residual StressCompressive)

(97) A process as described in example 11 is employed. With the following alterations:

Stress Controlling System

(98) TABLE-US-00059 Stress Controlling Layer 1 Dual rotatable Power 30 kW @ 27 kHz Silicon Target 99.90% Total Gas flow Argon 160 sccm Oxygen 261 sccm RPM 8.4 Number of rounds 25 Base Pressure 3e5 (mbar) Run Pressure 2e3 (mbar) Thickness 130 nm

(99) The measured residual stress of layers was determined and the durability performance was tested. The results are set out in Tables 32, 33, and 34, respectively.

(100) TABLE-US-00060 TABLE 32 Measured stress of the layers Layer Stress Stress controlling layer 108 MPa Total residual stress 6 MPa

(101) TABLE-US-00061 TABLE 33 Durability Performance Test Duration Result Dry heat Test 115 C. Pass

(102) TABLE-US-00062 TABLE 34 Optical Measurement Data Photopic reflection Y = 58.79% Photopic transmission Y = 0.0% Reflected colour target on transparent L* = 81.18 substrate - CIE L*a*b* scale measured with a* = 0.87 illuminant A/2 b* = 0.7

Example 13Bright Chrome (Zero Optical TransmissionLow Residual StressTensile)

(103) A process as described in example 11 is employed. With the following alterations:

Stress Controlling System

(104) TABLE-US-00063 Stress Controlling Layer 1 Dual rotatable Silicon Target Power 30 kW @ 27 kHz 99.90% Total Gas flow Argon 160 sccm Oxygen 261 sccm RPM 8.4 Number of rounds 3 Base Pressure (mbar) 3e5 Run Pressure (mbar) 2e3 Thickness 30 nm

(105) The measured residual stress of layers was determined and the durability performance was tested. The results are set out in Tables 35, 36, and 37, respectively.

(106) TABLE-US-00064 TABLE 35 Measured stress of the layers Layer Stress Stress controlling layer 38 MPa Total residual stress 5 MPa

(107) TABLE-US-00065 TABLE 36 Durability Performance Test Duration Result Dry heat Test 115 C. Fail (crazed)

(108) TABLE-US-00066 TABLE 37 Optical Measurement Data Photopic reflection Y = 57.33% Photopic transmission Y = 0.0% Reflected colour target on transparent L* = 80.37 substrate - CIE L*a*b* scale measured with a* = 0.50 illuminant A/2 b* = 0.27

Example 14Measure of Durability Under High Temperature Conditions

(109) For acceptability, decorative coatings need to have sufficient durability under conditions of operation and in many instances must meet regulated or industry/manufacturer guidelines. For automotive purposes a coating needs to show no crazing at temperatures of up to 115 C.

(110) In order to assess the durability of decorative coatings for automotive purposes a series of samples, having coatings with the same optical properties, were created with varying residual stress profiles. The samples were subjected to variable dry temperatures for a period of one hour to uncover any stress-related issues.

(111) The results of the testing are given below in Table 38. As can be seen samples having a decorative coating wherein the overall residual stress of the decorative coating was compressive demonstrated no crazing at temperatures up to 115 C., while samples with decorative coatings wherein the overall residual stress was tensile demonstrated crazing while hot at temperatures as low as 110 C.

(112) TABLE-US-00067 Film Film stress thickness Dry Heat Test (MPa) (nm) 100 C. 110 C. 115 C. 120 C. 125 C. 67 400 ok ok ok ok crazed 41 350 ok ok ok ok crazed 6 280 ok ok ok crazed crazed 5 175 ok crazed when crazed crazed crazed hot 16 210 ok crazed when crazed crazed crazed hot

(113) A person skilled in the art will understand that there may be variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all steps, features, compositions and compounds referred to, or indicated in this specification, individually or collectively, and any and all combinations of any two or more of the steps or features.

(114) The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.