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PRIMING COMPOSITION FOR CREATING A LIGHT ELECTRICALLY CONDUCTIVE PRIMING COATING

20230332000 · 2023-10-19

    Inventors

    Cpc classification

    International classification

    Abstract

    The invention relates to electrically conductive coatings, in particular to electrically conductive priming coatings of parts before they undergo electrostatic painting, as well as to priming compositions for creating such coatings (priming coatings). The present invention proposes a priming composition for creating a light, electrically conductive priming coating on a part prior to electrostatic painting, said priming composition comprising single-wall and/or double-wall carbon nanotubes at a concentration of greater than 0.005 wt. % and less than 0.1 wt. %, and having a degree of grinding of the priming composition of not more than 20 microns. The technical result of applying such a priming composition is a light, electrically conductive priming coating with a specific surface resistance of less than 10.sup.9 Ω/sq and a light reflection coefficient (LRV) of at least 60%. The present invention also proposes a method for preparing a priming composition and a light, electrically conducting priming coating.

    Claims

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    19. A priming formulation for enabling a light-colored conductive priming coating, the formulation comprising: single-walled and/or double-walled carbon nanotubes in a concentration of more than 0.005 wt. % and less than 0.1 wt. %; and 5 to 40 wt. % of one or several white pigments selected from a group consisting of magnesium oxide, zinc oxide, titanium dioxide, calcium carbonate, and barium sulphite, wherein a degree of grinding of the priming formulation is not more than 20 μm.

    20. The priming formulation of claim 19, wherein the priming formulation further comprises 0.1 to 2 wt. % of one or several dispersants selected from an alkyl ammonium salt of a high molecular weight copolymer and/or a linear polymer with polar groups, and/or a block copolymer with polar groups.

    21. The priming formulation of claim 19, wherein volume resistivity of the priming formulation is less than 10.sup.8 Ohm.Math.cm.

    22. The priming formulation of claim 19, wherein the priming formulation is a pseudoplastic non-Newtonian fluid with a flow behavior index in an Ostwald-de Waele power-law relationship of less than 0.7.

    23. The priming formulation of claim 19, wherein the priming formulation further comprises 0.1 to 5 wt. % of one or several rheology modifiers selected from a group consisting of bentonite, layered silicate, and modified layered silicate.

    24. A method for producing a priming formulation to produce a light-colored conductive priming coating of a part before electrostatic painting comprising: (A) introducing a concentrate of single-walled and/or double-walled carbon nanotubes, into a mixture comprising at least a solvent, wherein the concentrate is dispersive system comprising at least 1 wt. % of single-walled and/or double-walled carbon nanotubes obtained by mechanical processing of a mixture of carbon nanotubes and a dispersion medium to a grinding degree of not more than 50 μm, and (B) mixing the mixture from step (A) to form a homogeneous suspension with a grinding degree of not more than 20 μm.

    25. The method of claim 24, wherein the mixing at step (B) is performed using an overhead stirrer with a disk impeller, or using a rotor-stator type mixer.

    26. The method of claim 24, wherein the mixing at step (B) is performed a bead mill with a bead diameter of more than 0.4 mm and less than 1.8 mm and the bead volume to suspension volume ratio of more than 0.5 and less than 2 at the input energy of more than 10 W.Math.h/kg.

    27. The method of claim 24, wherein all other components of the priming formulation were introduced into the solvent and mixed before step (A), and steps (A) and (B) complete production of the priming formulation.

    28. The method of claim 26, wherein dispersants and a film-forming agent are introduced into the solvent before step (A), and at step (A), the concentrate of single-walled and/or double-walled carbon nanotubes and a white pigment are introduced into the mixture containing the solvent, dispersants, and a film-forming agent, and dispersion of the white pigment is performed at step (B), which completes the production of the priming formulation.

    29. A light-colored conductive priming coating produced by applying the priming formulation of claim 19 on a surface and then drying the priming formulation.

    30. The coating of claim 29, wherein drying of the coating is performed until a residual solvent concentration is not more than 20 wt. %.

    31. The coating of claim 29, wherein the coating is applied to polymer material with a surface resistance of more than 10.sup.10 Ohm/square or to a composite material with the surface resistance of more than 10.sup.10 Ohm/square.

    32. The coating of claim 31, wherein the polymer material is polypropylene, polyamide, polycarbonate, a copolymer of acrylonitrile, butadiene and styrene, or a mixture thereof.

    33. The coating of claim 31, wherein the composite material is talc-filled polypropylene, glass-filled polyamide, carbon-filled polyamide, or polyester sheet press-material.

    Description

    BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

    [0036] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

    [0037] In the drawings:

    [0038] FIG. 1 shows transmission electron micrograph of single-walled carbon nanotubes used in Examples 1-3.

    [0039] FIG. 2 show dynamic viscosity η, mPa.Math.s, of the priming formulations of Examples 1-9 versus the rotation speed of viscosity meter spindle ω, in rpm.

    [0040] FIG. 3 shows surface resistivity of the priming coating, Rs, Ohm/□, and light reflectance value, LRV, %, of the priming coating versus the concentration of single-walled and/or double-walled carbon nanotubes in the priming formulation. Numbers next to the points indicate Example numbers.

    [0041] FIG. 4 shows transmission electron micrograph of single-walled and double-walled carbon nanotubes used in Example 6.

    DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

    [0042] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

    [0043] For convenience, the information is also provided in the table below.

    TABLE-US-00001 TABLE 1 Substrate features Priming coating features Rs, LRV, Thickness, Rs, LRV, Substrate Ohm/□ % μm Ohm/□ % Polypropylene More than 72 16 6.3 .Math. 10.sup.4 72 10.sup.12 ABS More than 80 16 5.0 .Math. 10.sup.4 72 copolymer 10.sup.12 Polycarbonate More than 80 16 6.3 .Math. 10.sup.4 72 10.sup.12 Polyamide More than 80 15 5.0 .Math. 10.sup.4 72 10.sup.12 Talc-filled More than 85 17 6.3 .Math. 10.sup.4 73 polypropylene 10.sup.12 Glass-filled More than 83 16 6.3 .Math. 10.sup.4 72 polyamide 10.sup.12 Carbon-filled More than 26 15 6.3 .Math. 10.sup.4 63 polyamide 10.sup.12

    EXAMPLES

    Example 1

    [0044] The priming formulation was produced with commercially available carbon nanotube concentrate TUBALL™ MATRIX 302 comprising 10 wt. % of TUBALL™ single-walled carbon nanotubes (SWCNT) and 90 wt. % of a mixture of propane-1,2-diol with sodium 2,2′-[(1,1′-biphenyl)-4,4′-diyldi-2,1-ethylenediyl]bis-(benzene sulphonate) and produced by mechanically processing a mixture of carbon nanotubes and dispersion medium to the grinding degree of the mixture 40 μm. A transmission electron micrograph of single-walled carbon nanotubes in the used concentrate is shown in FIG. 1. In a metal 1.5 liter container, 100.0 g of titanium dioxide DuPont R706 and 9.9 g of carbon nanotube concentrate TUBALL™ MATRIX 302 were simultaneously introduced into a pre-mixed mixture comprising 546.1 g of commercially available aqueous emulsion of acryl resin Lacryl 8810 with non-volatiles content 44 wt. %, 327.0 g of distilled water, 14.0 g of an acrylic polymer-based dispersing agent Kusumoto Disparlon AQ D-400, 2 g of a vegetable oil-based deaerating agent WS 360, and 1.0 g of a rheology modifier based on modified layered silicates Laponite-RD. The obtained mixture was mixed using a rotor-stator type mixer IKA T50 digital ULTRA-TURRAX at rotation speed 10000 rpm for 40 minutes until a homogeneous suspension was formed. The SWCNT content in the produced priming formulation was 0.099 wt. %. The volume resistivity of the priming formulation was 3.5.Math.10.sup.3 Ohm.Math.cm, the degree of grinding of the priming formulation was 19 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.43.

    [0045] The obtained priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 24 hours. The post-drying thickness of the priming coating was 17 μm. The surface resistivity of the priming coating was 7.2.Math.10.sup.4 Ohm/□. The measured light reflectance value (LRV) of the priming coating was 60%. The data on light reflectance values and surface resistivities of the coatings obtained in this Example and in the Examples 2-9 below are shown in FIG. 3.

    Example 2

    [0046] The priming formulation was prepared using commercially available carbon nanotube concentrate TUBALL™ MATRIX 302, as in Example 1. In a metal 1.5 liter container, 124.0 g of barium sulphate “Barit”, 124.0 g of calcium carbonate “Microcaltsit KM-2”, 248.0 g of titanium dioxide DuPont R706, and 8.5 g of carbon nanotube concentrate TUBALL™ MATRIX 302 were simultaneously introduced into a mixture comprising 389.7 g of commercially available aqueous emulsion of acryl resin Lacryl 8810 with non-volatiles content 44 wt. %, 96.7 g of distilled water, 24.2 g of an acrylic polymer-based dispersing agent Kusumoto Disparlon AQ D-400, and 3 g of a vegetable oil-based deaerating agent WS 360. The mixture was mixed using a bead mill Dispermat CN 20 with a mill chamber TML1 with the diameter of the outer impeller 40 mm and internal disk 60 mm, with the diameter of zirconium beads being in the range of 1.2 mm to 1.7 mm, with zirconium oxide beads to mixture volume ratio in the mill chamber 8:13. Mixing was performed at impeller rotation speed 10.7 m/sec (3,400 rpm) for 30 minutes until a homogeneous suspension was formed; the total input energy was 46.8 W.Math.h/kg. After that, 60.0 g of the obtained mixture was mixed with a mixture comprising 31.8 g of commercially available aqueous emulsion with non-volatiles content 44 wt. % Lacryl 8810, 7.8 g of distilled water, 0.014 g of a vegetable oil-based deaerating agent WS 360, and 0.01 g of a rheology modifier based on modified layered silicates Laponite-RD. Mixing was performed using an overhead stirrer for 15 minutes, the rotation speed was 1.9 m/sec (1,500 rpm, impeller diameter 20 mm). The SWCNT content in the produced priming formulation was 0.05 wt. %.

    [0047] The volume resistivity of the priming formulation was 3.4.Math.10.sup.3 Ohm-cm, the degree of grinding of the priming formulation was 17.5 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.32. The prepared priming formulation was applied on polymer substrates made of polypropylene, ABS copolymer, polycarbonate, polyamide, talc-filled polypropylene, glass-filled polyamide, carbon-filled polyamide using a spray gun and dried at a room temperature for 24 hours. The post-drying thicknesses of priming coatings, their surface resistivities and light reflectance values (LRV), as well as surface resistivities and light reflectance values for the substrates before applying the priming coating are provided in Table 1.

    Example 3

    [0048] The priming formulation was prepared using commercially available carbon nanotube concentrate TUBALL™ MATRIX 302, as provided in Example 1. In a metal 1.5 liter container, 124.0 g of barium sulphate “Barit”, 124.0 g of calcium carbonate “Microcaltsit KM-2”, 248.0 g of titanium dioxide DuPont R706, and 17.0 g of carbon nanotube concentrate TUBALL™ MATRIX 302 were simultaneously introduced into a pre-mixed mixture comprising 389.7 g of commercially available aqueous emulsion of acryl resin Lacryl 8810 with non-volatiles content 44 wt. %, 96.7 g of distilled water, 24.2 g of an acrylic polymer-based dispersing agent Kusumoto Disparlon AQ D-400, and 3 g of a vegetable oil-based deaerating agent WS 360. The mixture was mixed using a rotor-stator type mixer IKA T50 digital ULTRA-TURRAX at rotation speed 10000 rpm for 40 minutes until a homogeneous suspension was obtained. After that, 60.0 g of the obtained mixture was mixed with a mixture comprising 31.8 g of commercially available aqueous emulsion with non-volatiles content 44 wt. % Lacryl 8810, 7.8 g of distilled water, 0.014 g of a vegetable oil-based deaerating agent WS 360, and 0.01 g of a rheology modifier based on modified layered silicates Laponite-RD. Mixing was performed using an overhead stirrer for 15 minutes, rotation speed was 3.4 m/sec (1,500 rpm, impeller diameter 40 mm) until a homogeneous suspension was formed.

    [0049] The produced priming formulation comprises 0.099 wt. % SWCNT. The volume resistivity of the priming formulation was 7.8.Math.10.sup.2 Ohm.Math.cm, the degree of grinding of the priming formulation was 19 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.41. The prepared priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 24 hours. The post-drying thickness of the priming coating was 17 μm. The surface resistivity of the priming coating was 1.3.Math.10.sup.4 Ohm/□. The measured light reflectance value (LRV) of the priming coating was 62%.

    Example 4

    [0050] The priming formulation was prepared using a carbon nanotube concentrate comprising 5 wt. % of single-walled carbon nanotubes and 95 wt. % of a mixture of triethylene glycol dimethacrylate and alkyl ammonium salt of high molecular weight copolymers and produced by mechanically processing a mixture of carbon nanotubes and dispersion medium to the grinding degree of the mixture 35 μm. In a metal 500 mliter container, 36.6 g of titanium dioxide DuPont R706 and 2.0 g of the carbon nanotube concentrate were simultaneously introduced into a pre-mixed mixture of 108.2 g of 20 wt. % solution in xylene of commercially available adhesion promoter Superchlon 822S, 1.0 g of a dispersant Disperbyk 118, 1.8 g of a rheology modifier based on modified silicates Claytone HY, 17.2 g of xylene, and 1.3 g of toluene. The mixture was mixed using a bead mill Dispermat CN 20 with an add-on module APS-500, a polyamide disk with the diameter 60 mm, with zirconium oxide beads to mixture volume ratio 1:1 for 30 minutes at rotation speed 8.5 m/sec (2,700 rpm) until a homogeneous suspension was formed. A mixture comprising 5.5 g of 20 wt. % solution in xylene of commercially available adhesion promoter Superchlon 822S, 7.2 g of toluene and 3.0 g of xylene was added to 84.2 g of the obtained mixture, and mixed using an overhead stirrer for 15 minutes at rotation speed 3.1 m/sec (1,500 rpm, impeller diameter 40 mm).

    [0051] The produced priming formulation comprises 0.099 wt. % SWCNT. The volume resistivity of the produced priming formulation was 6.0.Math.10.sup.4 Ohm.Math.cm, the degree of grinding of the priming formulation was 15 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.42. The obtained priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 20 minutes. The post-drying thickness of the priming coating was 12 μm. The surface resistivity of the priming coating was 7.9.Math.10.sup.5 Ohm/□. The measured value of light reflectance value (LRV) of the priming formulation was 74%.

    Example 5

    [0052] The priming formulation was prepared using a carbon nanotube concentrate comprising 2 wt. % of single-walled carbon nanotubes and 98 wt. % of a mixture of triethylene glycol dimethacrylate and alkyl ammonium salt of high molecular weight copolymers and produced by mechanically processing a mixture of carbon nanotubes and dispersion medium to the grinding degree of the mixture 20 μm. In a metal 1.5 liter container, 214.0 g of barium sulphate “Barit” and 2.5 g of the carbon nanotube concentrate were simultaneously introduced into a pre-mixed mixture of 172.0 g of commercially available acryl resin Degalan LP 64/12, 600.5 g of butyl acetate, 6.0 g of a dispersant Disperbyk 118, and 5.0 g of a rheology modifier based on modified silicates Claytone HY. The mixture was mixed using a bead mill Dispermat CN 20 with a mill chamber TML1 with the diameter of the outer impeller 20 mm and internal disk 60 mm, with the diameter of zirconium beads in the range of 0.8 mm to 1.0 mm, with the zirconium oxide beads to mixture volume ratio in the mill chamber 8:13. Mixing was performed at impeller rotation speed 10.7 m/sec (3,400 rpm) for 30 minutes until a homogeneous suspension was formed; the total input energy was 46.8 W.Math.h/kg.

    [0053] The produced priming formulation comprises 0.005 wt. % SWCNT. The volume resistivity of the priming formulation was 3.4.Math.10.sup.8 Ohm.Math.cm, the degree of grinding of the priming formulation was 12 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.35. The prepared priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 24 hours. The post-drying thickness of the priming coating was 12 μm. The surface resistivity of the priming coating was 9.8.Math.10.sup.8 Ohm/□. The measured light reflectance value (LRV) of the priming coating was 77%.

    Example 6

    [0054] The priming formulation was prepared using a carbon nanotube concentrate comprising 1 wt. % of single-walled and double-walled carbon nanotubes and 99 wt. % of a mixture of triethylene glycol dimethacrylate, a linear polymer with highly polar pigment-affine groups, and alkyl ammonium salt of high molecular weight copolymers and produced by mechanically processing a mixture of carbon nanotubes and dispersion medium to the grinding degree of the mixture 23 μm. A transmission electron micrograph of single-walled and double-walled carbon nanotubes in the used concentrate is shown in FIG. 4. In a metal 1.5 liter container, 50 g of the carbon nanotube concentrate were introduced into a pre-mixed mixture of 172.0 g of commercially available acryl resin Degalan LP 64/12, 553.0 g of butyl acetate, 6.0 g of a dispersant Disperbyk 118, and 5.0 g of a rheology modifier based on modified silicates Claytone HY.

    [0055] The obtained mixture was mixed using an overhead stirrer at rotation speed 6.3 m/sec (2000 rpm, impeller diameter 60 mm) until a homogeneous suspension was formed. After that, 214.0 g of titanium dioxide DuPont R706 were additionally introduced into the mixture and mixed using a bead mill Dispermat CN 20 with a mill chamber TML1 with the diameter of outer impeller 40 mm and internal disk 60 mm, with the diameter of zirconium beads in the range of 0.8 mm to 1.0 mm, with the zirconium oxide beads to mixture volume ratio in the mill chamber 8:13. Mixing was performed at impeller rotation speed 10.7 m/sec (3,400 rpm) for 30 minutes; the total input energy was 46.8 W.Math.h/kg.

    [0056] The produced priming formulation comprises 0.05 wt. % of single-walled and double-walled carbon nanotubes. The volume resistivity of the priming formulation was 5.6.Math.10.sup.4 Ohm.Math.cm, the degree of grinding of the priming formulation was 14 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.40. The prepared priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 24 hours. The post-drying thickness of the priming coating was 14 μm. The surface resistivity of the produced priming coating was 3.7.Math.10.sup.5 Ohm/∇. The measured light reflectance value (LRV) of the priming coating was 73%.

    Example 7

    [0057] The priming formulation was prepared using commercially available carbon nanotube concentrate TUBALL™ MATRIX 204 comprising 10 wt. % of single-walled carbon nanotubes and 90 wt. % of a mixture of triethylene glycol dimethacrylate and alkyl ammonium salt of high molecular weight copolymers and produced by mechanically processing a mixture of carbon nanotubes and dispersion medium to the grinding degree of the mixture 40 μm. In a glass 150 ml container, 0.5 g of carbon nanotube concentrate TUBALL™ MATRIX 204 was introduced into a pre-mixed priming mixture comprising 13 g of commercially available acrylic resin Dianal BR-116 (40 wt. % solution in toluene), 25.7 g of commercially available acrylic resin Superchlone 930S (solution 20 wt. % in xylene), 23.7 g of xylene, 11.9 g of butyl acetate, 24.0 g of titanium dioxide DuPont R706, 0.5 g of a rheology modifier based on modified silicates Claytone 40, and 0.6 g of a dispersant Disperbyk 118. The mixture was mixed using an overhead stirrer for 20 minutes until a homogeneous suspension was formed, rotation speed was 4.2 m/sec (2000 rpm, impeller diameter 40 mm). The produced priming formulation comprises 0.05 wt. % SWCNT. The volume resistivity of the produced priming formulation was 5.0.Math.10.sup.4 Ohm.Math.cm, the degree of grinding of the priming formulation was 15 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.31.

    [0058] The produced priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 10 minutes. The post-drying thickness of the priming coating was 17 μm. The surface resistivity of the produced priming coating was 6.3.Math.10.sup.5 Ohm/□. The measured light reflectance value (LRV) of the priming coating was 67%.

    Example 8

    [0059] The priming formulation was prepared using commercially available carbon nanotube concentrate TUBALL™ MATRIX 204, as provided in Example 7. In a metal 500 ml container, 48.0 g of titanium dioxide DuPont R706 and 1.0 g of commercially available carbon nanotube concentrate TUBALL™ MATRIX 204 were simultaneously introduced into a pre-mixed mixture of 26.0 g of commercially available acrylic resin Dianal BR-116 (40 wt. % solution in toluene), 51.4 g of commercially available acrylic resin Superchlone 930S (solution 20 wt. % in xylene), 47.2 g of xylene, 24.0 g of butyl acetate, 1.0 g of a rheology modifier based on modified silicates Claytone 40, and 1.2 g of a dispersant Disperbyk 118. The mixture was mixed using a bead mill Dispermat CN 20 with an add-on module APS-500, a polyamide disk with diameter 60 mm, with the zirconium oxide beads to mixture volume ratio 1:1 for 30 minutes at rotation speed 8.5 m/sec (2,700 rpm) until a homogeneous suspension was formed; the total input energy was 37.2 W.Math.h/kg. The produced priming formulation comprises 0.05 wt. % SWCNT. The volume resistivity of the priming formulation was 4.8.Math.10.sup.5 Ohm.Math.cm, the degree of grinding of the priming formulation was 14 μm. As follows from the dynamic viscosity of the priming formulation versus the rotation speed of the viscometer spindle shown in FIG. 2, the priming formulation meets the Ostwald-de Waele power-law relationship with a flow behavior index of 0.41.

    [0060] The obtained priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 30 minutes. The post-drying thickness of the priming coating was 14 μm. The surface resistivity of the priming coating was 2.5.Math.10.sup.5 Ohm/□. The measured light reflectance value (LRV) of the priming coating was 72%.

    Example 9. (Comparative)

    [0061] The priming formulation was prepared similarly to Example 4, although 20.0 g of carbon nanotube concentrate was introduced. The produced priming formulation comprises 0.5 wt. %. The volume resistivity of the produced priming formulation was 1.2.Math.10.sup.2 Ohm.Math.cm, and its degree of grinding was 26 μm. As can be seen from FIG. 2, the produced priming formulation has an extremely high viscosity, which limits possible methods of its application on a substrate. The priming formulation was applied on a polymer substrate made of polypropylene using a spray gun and dried at a room temperature for 24 hours. The post-drying thickness of the priming coating was 34 μm. The surface resistivity of the produced priming coating was 7.6.Math.10.sup.2 Ohm/□. The measured value of light reflectance value (LRV) was 54%. Thus, the produced priming formulation is not sufficiently light-colored.

    INDUSTRIAL APPLICABILITY

    [0062] The present invention can be used to produce conductive priming coatings with a light reflectance value at least 60% on the parts made of polymer or composite materials with the surface resistance more than 10.sup.10 Ohm/square before electrostatic painting, as well as in the production of priming formulations to produce such coatings.

    [0063] Having thus described a preferred embodiment, it should be apparent to those skilled in the art that certain advantages of the described method and apparatus have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention.