Description:TECHNICAL FIELD
The present disclosure relates to a multilayer coating film. The coating film of present disclosure is used for manufacturing of Inlay which will be useful for producing Radio-Frequency Identification (RFID) and Information Technology Outsourcing (ITO) antenna. The coating film of present disclosure can be applied on various olefin films, which helps to improve anchorage with enamel coated Cu-wire to base films, which helps to produce stable antenna on base film material.

BACKGROUND
The use of Radio Frequency Identification (RFID) systems has considerably increased recently. RFID technologies are used, for example, in logistics and access control. The communication protocol and coupling are based on electromagnetic waves and fields. (C. Ramade et al., Int. J. Radio Frequency Identification Technology and Applications, Vol. 4, No. 1, 2012). Most of RFID applications are in the Low frequency (LF), High Frequency (HF) and Ultra High Frequency (UHF) ranges. The HF labels are widely used in RFID systems and they consist of four main components: a substrate that can be Polyethylene Terephthalate (PET), PVC or paper, a metallic coil as “antenna” made of copper, aluminium, a RFID chip to store data and an overlay PVC, epoxy, adhesive, depending on application requirements.

The substrate holds all other tag components together. The tag antenna is deposited or printed on the substrate, and the IC is then attached to this antenna. The substrate material must be able to withstand various environmental conditions through which the tag may pass during its lifecycle. Some of the materials used for the substrate are polymer, PVC, Polyethylenetherephtalate (PET), phenolics, polyesters, styrene, and even paper. The substrate material must provide dissipation of static build-up, a smooth printing surface for antenna layout, durability and stability under various operating conditions, and mechanical protection for the antenna, chip, and their interconnections. The RFID tags, based on polymer substrates, possess very enticing characteristics like high flexibility, crumpling and stretchability, ease of processability, corrosion and humidity resistance, and most importantly a low cost with easy fabrication. The substrates include but are not limited to polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE) and polydimethylsiloxane (PDMS).

9652/DELNP/2011 discloses a microporous materials comprising: (a) a polymeric matrix comprising a renewable polymer and optionally a polyolefin that is the same as or different from the renewable polymer, (b) finely divided, particulate filler distributed throughout the matrix, and (c) at least 35 percent by volume of a network of interconnecting pores communicating throughout the microporous material. Also provided are multilayer articles prepared from the above-described microporous materials.

JP2007511383A relates to thin flexible RFID tags in the molding process of handlers, transporters, carriers, trays and similar handling devices utilized in the semiconductor and sensitive electronic component processing industry. The RFID tags are bonded or encapsulated between two thermoplastic polymer film layers to from an RFID tag stack, the RFID tag laminate is then selectively placed along the molding surface within the mold cavity to align with the desired target surface of the moldable molten resin material. The molding process allows one surface of the two film layers to be bonded to the contact surface of the moldable material and the RFID tag laminate to be permanently and integrally bonded to the moldable material.

EP2709042B1 relates to a multilayer article comprising a first substrate having a first carrier layer and at least one further (second) substrate having a second carrier layer which on at least one side at least partially provided with a cold seal adhesive layer and just joined together by the contact of their respective cold seal adhesive layer are a method for producing such an article as well as the use of a printer having at least two bends and at least one cutting device for producing such objects.

The available films used as inlay for Radio-Frequency Identification (RFID), Near-field communication (NFC) antennas have single films which are porous in nature and have softening point at higher temperature, when enameled coated copper wire is embedded using an ultrasonic embedding machine, coated wire bonds mechanically and chemically to films and produces antenna on inlay which are useful in Producing tags for sensor application. However, available non coated base film does not give enough bonds to produce stable antennas. Current embedding application methods, employ a single layer pour films, but there is no specific functional coating available which can be applied on non-pours film which shows embedding performance. Thus, there exist need for a functional coating which will enhance or improve anchorage of olefin films to enamel coated copper wire so that it can produce a stable antenna for Near-field communication (NFC) and Radio-Frequency Identification (RFID) tag manufacturing.

OBJECTIVE
An objective of the present disclosure is to provide a novel functional coating on plastic film for manufacturing of Inlay or film useful for producing RFID, ITO antenna.

Further an objective of the present disclosure is to provide a functional coating that will enhance or improve anchorage of olefin films to enamel coated copper wire for producing a stable antenna for NFC and RFID tag manufacturing.

Yet another objective of the present disclosure is to provide a functional coating for producing NFC and RFID tag by screen printing method using conductive inks.

Yet another objective of the present disclosure is to provide a functional coating that can be applied on any olefin film of any thickness to produce a stable antenna.

Yet another objective of the present disclosure is to provide a functional coating which increase anchorage to base material at lower deposition by mechanically/ chemically interlocking with enamel coated Cu wire.

SUMMARY
An aspect of the present disclosure provides a multilayer coating film comprising a functional coating layer (1), a primer coat layer (2) and an opaque film (3), wherein the functional coating layer (1) comprises a wetting agent in the range of 0.05 – 0.2 wt%, a silica treated wax fine powder in the range of 10 – 15 wt%, a polymer dispersion in the range of 15 – 20 wt%, a polymer emulsion in the range of 20 – 30 wt%, an anti-blocking agent in the range of 0.5 – 1 wt%, and remaining water.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying drawings where:

Figure 1(a) illustrates a cross sectional view of multi-layer functional coating for construction of film/inlay material.

Figure 1(b) illustrates a cross sectional view of enamel coated copper wire on multilayer film/ inlay material.

Figure 1(c) illustrates a cross sectional view showing copper wire penetration to multi-layer film/ inlay to form bonding with the film.

DETAILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
The present disclosure relates to a multilayer coating film with a functional layer (1), a primer coat layer (2) and an opaque film (3). The functional coating layer (1) comprises a wetting agent in the range of 0.05 – 0.2 wt%, a silica treated wax fine powder in the range of 10 – 15 wt%, a polymer dispersion in the range of 15 – 20 wt%, a polymer emulsion in the range of 20 – 30 wt%, an anti-blocking agent in the range of 0.5 – 1 wt% and remaining water.
In an embodiment of the present disclosure, a multiplayer film is provided wherein the wetting agent is selected from the group consisting of an aqueous emulsion of a structured acrylate copolymer with pigment-affinic groups, acrylic wetting agent, and Polyether polyester base agent or a combination thereof.
In an embodiment of the present disclosure, a multiplayer coating film is provided wherein the silica treated wax fine powder is selected from the group consisting of Carnauba and paraffin wax with precipitated silica or micronized organic polymers having particle size below 0.5 microns.

Another embodiment of the present disclosure provides a multilayer coating film wherein that the polymer dispersion is an aliphatic urethane hybrid dispersion selected from aliphatic linkage dispersion which are derived from any one of polyol as having linkage polyether, polyester and polycarbonate.
In yet another embodiment of the present disclosure, a multiplayer coating film is provided wherein the polymer emulsion is selected from the group consisting of polyethylene wax dispersion and a dispersion consisting of non-cross linkable heat sealable acrylic polymers.
In further embodiment of the present disclosure, a multiplayer coating film is provided wherein the anti-blocking agent is selected from the group consisting of paraffin wax, carnauba wax, polyethylene wax and Fischer-Tropsch Waxes.
In yet another embodiment of the present disclosure, a multiplayer coating film is provided wherein the primer coat layer (2) comprises polyurethane resin dispersion having single material of aliphatic urethane hybrid dispersion and water as diluent.
An embodiment of the present disclosure provides a multilayer coating film wherein the opaque layer (3) comprises a polyethylene film having thickness in the range of 20 microns to 200 microns and a polypropylene film having thickness in the range of 20 microns to 100 microns.
Another embodiment of the present disclosure also provides a multilayer coating film wherein the functional coating layer (1), the primer coat layer (2) and the opaque layer (3) are present in a thickness ratio in the range of 1-4:0.04-0.6:10-60.
Yet another embodiment of the present disclosure provides a multilayer coating film wherein the functional coating layer (1) is present in a thickness in the range of 5 microns to 20 microns.
Yet another embodiment of the present disclosure provides a multilayer coating film wherein the primer coat layer (2) is present in a thickness in the range of 0.2 microns to 3 microns.
Further an embodiment of the present disclosure provides a multilayer coating film wherein the opaque layer (3) is present in a thickness in the range of 50 microns to 300 microns.
The water based multilayer coating film of the present disclosure is prepared by using PU (polyurethane) Dispersion, Waxes having inorganic treatment on surface and PE Waxes. Prepared water-based formulations are coated on corona treated film by using a lab coater (R.K Coater) at various deposition thickness. Coated films are dry in a hot air oven, placed for maturation period of one day for complete curing of coating.
The obtained multilayer film is shown in Figure1a. Figure 1a illustrates a cross sectional view of a multilayer layer functional coating of film/ inlay material including a functional coating (1) to help bonding of embedded copper wire, a primer coat layer (2) and a base multilayer flexible opaque film (3).
Figure 1b illustrates a cross sectional view of enamel coated copper wire of 0.1 to 1 micron being embedded on a multilayer functional coating. The copper wire (B) is coated with enamel (A).
Figure 1c illustrates a cross sectional view where a copper wire penetrates to multi-layer film/ inlay and forms bonding with the film useful for designing a stable antenna. The copper wire (B) with enamel coating (A) is embedded in the multilayer functional coating where area (C) represents penetration region of copper wire (B) and fusing of copper enamel (A) with coating layer (1) and /or primer layer (2)

The films of present disclosure can be applied on varies olefin films, which helps to improve anchorage with enamel coated Cu-wire to base films, which helps to produce stable antenna on base film material.

EXAMPLES
The following examples are given by way of illustration of the present disclosure and should not be construed to limit the scope of present disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the subject matter.

Materials used in the coating film of present disclosure are given below in Table 1:

Table 1:
Sr.No Material Category Examples with
trade name Range
(Overall)
1 Polyether polyester base water base wetting agent Wetting & dispersing agent Disperse BYK2010,BYK2060 0.05-0.2%
2 Spherical micronized functional blend of wax with homogeneously distributed silica on surface. Treated Wax Ceretan MXS 3815,Ceratan MX9820,Ceretan MXF10325 10-15%
3 Aliphatic urethane hybrid dispersion for filmic primer application. Resin/Binder Neorez R600, Neorez R4000 15-20%
5 Acrylic binder Resin/Binder Resin SJ32,Resin SJ38 15-20%
6 Low temperature Heat sealable modified Polyethylene wax dispersion Heat seal Resin/Binder Joncryl HSL 9012,Joncryl HSL 9055 20-30%
7 nanoscale wax emulsions, mostly carnauba
and paraffin-based. Which reduce COF and improve blocking without affecting seal performance. Antiblocking agent Lube ML 160,Allinova IES-CWF ,Byk Aquacer 531. 0.5-1%
8 polyfunctional aziridine liquid cross-linker Crosslinker Crosslinker CX-100, Stahl XR-2514 0.05-0.5 %
Example 1: Preparation of a multilayer coating film and testing of prepared coating
For preparing a multilayer coating film:
1. Known quantity of PU Dispersion resin is taken in a beaker, wetting and dispersing agent (Polyether polyester base water base wetting agent) is added and mixed in high-speed cowl dispersion under 300-400RPM.
2. After 10 min. of mixing, Aluminum silicate is added slowly and mixed at high speed 1000 to 1200RPM for 30 min.
3. After foam stabilizing, viscosity and solid of final coating is measured.
4. Above sample are coated on 300-micron olefin film with or Without primer interlayer using RK Coated by Myer bar system to achieve desire coat weight.
5. Coated film is dried at 70-90°C for 1 min in hot air circulated oven and tested further for Embedding application.
The above preparation of multilayer coating film is Experiment 1A. The same process has been followed for Expt 1 B, Expt 1C, Expt. 1D & Expt.1E mentioned below:
TABLE 2:
Expt 1A Expt 1B Expt 1C Expt 1D Expt 1E
PU Dispersion (Aliphatic urethane hybrid dispersion for filmic primer application) 86.78 92 86.95 85.68 92
Nano CaCo3 1.4
Wetting agent 0.19 0.1 0.19 0.19 0.1
Aluminum silicate 13 6.97 12.91 12.7
Organic matting agent 1.4 6.97
Primer coat wt. 0.3 0.3 0.3 0.3 0.3
Top coat wt. 0.3 0.3 0.3 0.3 0.3
Embedding OK Poor embedding Poor embedding Poor embedding Poor embedding
Embedding force 0.04N - - - -

Different set of testing conducted employing different attrition with respect to material selection, adjusting pigment binder ration, improving blocking resistance, increase intercoat adhesion are conducted.
Experiment with PU dispersion (Tg from 10 to -10° C) with inorganic pigment and some heat seal PE Dispersion resin:
Above Table 1 shows different sets of testing with different combinations, in Experiment 1A Coated film was tested on hot tack test for peel and embedding performance and different set of experiments are conducted by considering PU resin as constant factor and varying pigment binder ratio (Expt 1B), By using Nano CaCO3 and Organic PU matting agent (Expt 1C,1D &1E). The experiment shows that in Experiment 1A at initial levels embedding was found to be ok (Indicated by embedding possible and require force to detached wire from film) and the peel force in Experiment 1A was found to be lower by targeted value 0.2 to 0.25 N of benchmark product. The different set of experiment by considering PU resin as constant factor and varying pigment binder ratio (Expt 1B), by using Nano CaCO3 and Organic PU matting agent (Expt 1C,1D &1E) resulted in poor embedding with achieved peel performance and thus there is need to select different binder combination for good fusing with enamel coated wire.

Example 2: Experimentation with PU dispersion and Heat Seal Resin:
To improve peel performance of embedded copper wire with substrate, different sets of experiments are conducted along with polymeric resin which shows characteristic of softening or sealing behavior at particular temperature (In our case 100 to 130°C), PE modified water base resin having sealing property temperature around 100 to 130°C is selected. Since, heat seal resins are sensible to temperature they show blocking tendency on flexible films after aging. Further, experiments are done to avoid blocking by adding cross liker solution, Wax solution in final coating formulation.

Table 3 shows different sets of testing perform with different combination of resin to binders, heat seal resins to PU Dispersion. For Table 3 for experiments 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H same process is followed as per Experiment 1A with same coating application method.
TABLE 3:
RM 2A 2B 2C 2D 2E 2F 2G 2H
Water 23.12 16.95 14.92 24.49 18.56 28 18.5 18.56
IPA 2.56 1.88 1.65 2.72 2.06 2.0625 2.062 2.06
Aluminum silicate 9.5 6.96 6.13 10.06 6.87 6.875 6.87 6.8
Wetting Agent 0.019 0.13 0.12 0.2
PU Dispersion (Aliphatic urethane hybrid dispersion for filmic primer application) 7.1 6.65 37.28 44 44 44 44
Low temperature Heat sealable modified Polyethylene wax dispersion 57.07 66.54 76.36 23.72 27.5 20 27.5 27.5
Antiblocking agent (nanoscale wax emulsions, mostly carnauba
and paraffin-based) 0.5 1 1 1 0.5 0.5 0.5
Crosslinker (polyfunctional aziridine liquid cross-linker) 0.44 0.44 0.44 0.44
Wax 4 0.5
Coating Parameter
Solid in % 26.59 26.5 26.2 27 26.59 26.5 26.2 27
Coat Wt. (In GSM) 12-13 12-13 12-13 12-13 12-13 12-13 12-13 12-13
Viscosity (Sec) B4 Cup 16 -17 17-18 16-29 16-19 16-19 16-19 16-19 16-19
Embedding Test
Peel Force(N) 0.1 0.09 0.1 0.2 0.1 0.09 0.1 0.2
Embedding (Yes/No) Yes Yes Yes Yes Yes Yes Yes Yes
Blocking (Yes/No) Yes Yes Yes Yes Yes Yes Yes Edge Blocking

Example 3: Preparation of a multilayer coating film and testing of prepared coating
For preparing a multilayer coating film:
1. Water is added in a clean beaker, wetting and dispersing additives are added and mixed well for 300 RPM.
2. Known quantity of resin solution is added in beaker.
3. After complete mixing of resin mixture, treated wax (Spherical micronized functional blend of wax with homogeneously distributed silica on surface) powder is added slowly for Hrs. under 1000RPM and is completely dispersed by High-speed stirring for around 1-2 Hrs.
4. After complete mixing, wax solution is added at 300-500RPM.
5. After foam stabilizing, viscosity and solid of final coating is measured.
6. The obtained coating solution is coated on 300-micron olefin film with varying coating weight, with or without primer.
7. The coated film is dried in oven 1 min at 70-80°C oven temperature.
The above preparation of multilayer coating film is method of preparation Experiment 3D.
For experiment 3A,3B & 3C same process is followed as per Experiment 1A.
Experiment with blocking improvement study:
To improve blocking and also to increase consistent peel performance from embedded copper wire to film, testings are carried out with special inorganic treated wax and selected different heat seal resins with combination of hard PU Dispersion resin.
Table 4 shows different sets of testing perform with different combination of special inorganic treated wax and selected different heat seal resins with combination of hard PU resin.

TABLE 4
RM 3A 3B 3C 3D 3E 3F 3G
Water 20.14 28.7 28 39.61 43.88 42.82 38.84
AL Silicate 0 7.5 7.5
Wetting agent 0 0.15 0.15 0.09 0.1 0.1 0.08
treated wax (Spherical micronized functional blend of wax with homogeneously distributed silica on surface) 7.52 2.8 2.5 12.38 13.71 13.38 12.13
Aliphatic urethane hybrid dispersion 44.16 29.7 7.8 16.5 18.28 17.84 16.18
Low temperature Heat sealable modified Polyethylene wax dispersion 27.6 31.18 53.66 25.37 23
Acrylic binder 21.94 24.3
nanoscale wax emulsions, mostly carnauba and paraffin-based 0.5 0.5 0.5 0.45 0.5 0.49 0.4
Aliphatic urethane hybrid dispersion 9.03 9.29
Coating Parameters
Solid in % 28 27.5 26.5 28.7 28.5 26 26.5
Coat Wt (GSM)
Viscosity (B4 sec) 16-18 16-18 16-18 16-18 16-18 16-18 16-18
Test Performance
Peel Force(N) 0.22 0.09 0.02 0.13 0.19 0.2 0.17
Embedding Yes Yes Yes Yes Yes Yes
Blocking Yes Yes Yes No Blocking No
Blocking No Blocking No Blocking

Example 4: Testing
To achieve bonding of enamel coated wire, below two factors are considered:
1) Material should soften at higher temperature (100-130° C) and also should crystallize fast and harden rapidly at short duration of time.
2) Material should also have fusing or boding property.
The multilayer coating employing different attritions are being tested for peel force, embedding performance and blocking tendency. The following tests are conducted:
1) Copper wire embedding or bonding test:
Coated film is tested for embedding involving the following steps:
a) Film is cut by dimension of 25 mm x 200 mm strips,
b) The enamel coated copper wire is placed on a coated film on a hot tack tester to simulate embedding application.,
c) The Hot tack test instrument is set for upper jaw temperature (100°C to 130°C) and lower jaw temperature for ambient temperature (25°C to 35°C), pressure & temperature is set by considering machine application pressure of 2 bar and dwell time of 800 milliseconds and
d) After the embedding process, the sample is observed for embedding (i.e., copper wire is bonded with film or not), if the copper wire is bonded successfully the embedded wire sample is tested further to measure peel force, where the peel force is measured by universal tensile machine with load cell of 500N with speed of 100mm/min to measure maximum peel strength in N.

2) Curve surface Bonding test:
To test that the finished product is a flexible film to match performance of a curve surface, embedded film was applied on curve surface and monitored for 24Hrs, curve surface track wires are observed for lifting and deboning, a good bonding resulted in no lifting and deboning.
3) Blocking Test:
The film is coated with heat sensitive polymer resin for enhancing blocking characteristics of film. The blocking sample is tested under load for particular duration. For carrying out blocking test a press machine is used with load of 2Ton for 2Hrs duration at 400 °C temperature after which blocking between films is observed.
Listed below are the various film test parameters.
Test Unit Coated Film
Total Thickness Mic 320
Total GSM Gm/m2 302
Opacity % 93.3
Gloss @ 45 Degree 5-10
Density g/cc 0.94
Tensile strength@ MD Kgf/cm2 258
Tensile strength@ TD Kgf/cm2 182
Elongation @ MD % 567
Elongation @ TD % 8.7

ADVANTAGES:
The multilayer coating film of the present disclosure is used as inlay for Radio-Frequency Identification (RFID), Near-field communication (NFC) antennas. The films of present disclosure are also useful for screen printing RFID, NFC antenna manufacturing. The multilayer coating film coating increase anchorage to base material at lower deposition by mechanically /chemically interlocking with enamel coated Cu wire, provided coatings are useful for producing RFID, NFC Tag by using conductive ink (Screen /silk printing) and also enamel coated copper wire embedding (Ultrasonic Copper wire embedding machine).
INDUSTRIAL APPLICABILITY:
The multilayer coating film of the present disclosure are Special functional coated film is used in NFC and RFID Tag manufacturing by Ultrasonic copper wire embedding machine.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit ad scop of the subject matter should not be limited to the description of the preferred embodiment contained therein. Certain modifications and improvements will occur to the person skilled in the art upon a reading of foregoing description. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of following claims. , Claims:WE CLAIM:

1. A multilayer coating film comprising:
a functional coating layer (1);
a primer coat layer (2); and
an opaque film (3);
wherein the functional coating layer (1) comprises:
a wetting agent in the range of 0.05 – 0.2 wt%;
a silica treated wax fine powder in the range of 10 – 15 wt%;
a polymer dispersion in the range of 15 – 20 wt%;
a polymer emulsion in the range of 20 – 30 wt%;
an anti-blocking agent in the range of 0.5 – 1 wt%; and
remaining water.

2. The multilayer coating film as claimed in claim 1, wherein the wetting agent is selected from the group consisting of an aqueous emulsion of a structured acrylate copolymer with pigment-affinic groups, acrylic wetting agent, and Polyether polyester base agent or a combination thereof.

3. The multilayer coating film as claimed in claim 1, wherein the silica treated wax fine powder is selected from the group consisting of Carnauba and paraffin wax with precipitated silica or micronized organic polymers having particle size below 0.5 microns.

4. The multilayer coating film as claimed in claim 1, wherein the polymer dispersion is an aliphatic urethane hybrid dispersion selected from aliphatic linkage dispersion which are derived from any one of polyol as having linkage polyether, polyester and polycarbonate.

5. The multilayer coating film as claimed in claim 1, wherein the polymer emulsion is selected from the group consisting of polyethylene wax dispersion and a dispersion consisting of non-cross linkable heat sealable acrylic polymers.

6. The multilayer coating film as claimed in claim 1, wherein the anti-blocking agent is selected from the group consisting of paraffin wax, carnauba wax, polyethylene wax and Fischer-Tropsch Waxes.

7. The multilayer coating film as claimed in claim 1, wherein the primer coat layer (2) comprises polyurethane resin dispersion having single material of aliphatic urethane hybrid dispersion and water as diluent.

8. The multilayer coating film as claimed in claim 1, wherein the opaque layer (3) comprises: a polyethylene film having thickness in the range of 20 microns to 200 microns and a polypropylene film having thickness in the range of 20 microns to 100 microns.

9. The multilayer coating film as claimed in claim 1, wherein the functional coating layer (1), the primer coat layer (2) and the opaque layer (3) are present in a thickness ratio in the range of 1-4:0.04-0.6:10-60.

10. The multilayer coating film as claimed in claim 1, wherein the functional coating layer (1) is present in a thickness in the range of 5 microns to 20 microns.

11. The multilayer coating film as claimed in claim 1, wherein the primer coat layer (2) is present in a thickness in the range of 0.2 microns to 3 microns.

12. The multilayer coating film as claimed in claim 1, wherein the opaque layer (3) is present in a thickness in the range of 50 microns to 300 microns.