Powder coating composition with stable antistatic effect and cured coating thereof

Abstract

The invention discloses a powder coating composition with a stable antistatic effect and a cured coating thereof, the powder coating composition comprises a powder coating base powder composition and conductive mica powder, at least part of the conductive mica powder is attached to the powder coating base powder composition, and the powder coating base powder composition comprises thermosetting resin and a curing agent; wherein the conductive mica powder comprises mica powder serving as an inner core, and the surface of the mica powder is coated with a conductive substance; the cured coating provided by the invention has a stable and excellent antistatic effect, and is especially suitable for preparing a coating coating on the surface of a related metal workpiece (such as an electrical cabinet and an electronic device) containing an electronic component with relatively high requirements on an electrostatic environment; and the coating is especially suitable for preparing metal product surface coating layers, such as door handles, which are frequently contacted with the human body.

Description

Technical Field

[0001] The invention belongs to the field of powder coatings, and in particular relates to a powder coating composition with a stable antistatic effect and a cured coating thereof. Background Art

[0002] Thermosetting powder coatings are widely used to replace paints and water-based paints to achieve protective decoration of products in various fields because of their advantages of being green, low energy consumption, easy to apply, and no (or at least very little) VOC emissions. Specifically, when the application conditions are in an environment with high requirements for electrostatic environment, the coating of the relevant workpieces in the environment is required to have a stable and reliable antistatic function.

[0003] The existing methods for preparing antistatic coatings mainly include the following two approaches: 1. Use intrinsic conductive polymer conductive coatings: For example, the invention patent with authorization announcement number CN102492349B discloses a water-based epoxy antistatic coating containing nano-poly (methyl methacrylate-butyl acrylate-acrylic acid) / polyaniline core-shell structure composite particles, which increases the dispersibility, chemical compatibility and storage stability of polyaniline to a certain extent, and obtains a coating with significant antistatic performance; for example, the invention patent with authorization announcement number CN103642383B uses polytetrahydrofuran diol, polycarbonate diol, isophorone diisocyanate and the like as raw materials, and prepares a photocurable antistatic resin by UV-curing sulfonate-type polyurethane acrylate prepolymer, and the coating prepared by this has good antistatic properties; there is little research on the solid resins used in these powder coatings; in addition, the material or process costs involved in the preparation process of the above materials are relatively high, making it difficult to achieve industrial-scale production and application.

[0004] 2. Use metal or carbon conductive fillers: Commonly used metals include silver powder, copper powder, nickel powder, etc.; carbon often includes flake graphite, graphene, carbon nanotubes, etc. For example, the invention patent application with publication number CN 102690566A uses flake zinc powder and copper powder as conductive fillers to prepare water-based antistatic coatings with excellent conductivity; for example, the invention patent application with publication number CN113956772A prepares a coating by adding 0.5-3 parts of graphene, and the surface resistance reaches 108Ω; for example, the invention patent application with publication number CN 105385329A prepares a coating by pre-treating carbon nanotubes and then adding them to the polyurethane coating system, showing an outstanding antistatic effect; however, the preparation of antistatic coatings by adding metal powders has the following defects: On the one hand, it will inevitably affect the decorativeness of the paint film (metallic effect); on the other hand, during actual use, the metal material will undergo an oxidation reaction with the oxygen in the air to become oxides, resulting in a decrease in the antistatic effect; and the use of carbon-based antistatic coatings has stable antistatic properties, but the material is expensive, and its black color makes it difficult to prepare a light-colored or even white coating appearance.

[0005] Therefore, the applicant hopes to conduct research and development to solve the above technical problems. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a powder coating composition with a stable antistatic effect and a cured coating thereof, wherein the cured coating has a stable and excellent antistatic effect and is particularly suitable for preparing coatings on the surfaces of related metal workpieces (such as electrical cabinets, electronic devices, etc.) containing electronic components that have high requirements for electrostatic environments; it is also particularly suitable for preparing coatings on the surfaces of metal products that frequently come into contact with the human body, such as door handles, etc.

[0007] The technical solution adopted by the present invention is as follows: A powder coating composition with a stable antistatic effect comprises a powder coating base composition and conductive mica powder, at least part of the conductive mica powder is attached to the powder coating base composition, and the powder coating base composition comprises a thermosetting resin and a curing agent; wherein the conductive mica powder comprises mica powder as a core, and the surface of the mica powder is coated with a conductive substance.

[0008] Preferably, the resistivity of the conductive mica powder is >900 MΩ·cm, more preferably >1000 MΩ·cm; the test standard for the resistivity involved in the entire application is GB / T 39978-2021, and the resistivity of the conductive mica powder specifically refers to the volume resistivity of the conductive mica powder.

[0009] Preferably, the D50 particle size of the conductive mica powder is less than 60 microns, more preferably less than 50 microns, more preferably 20-50 microns.

[0010] Preferably, the oil absorption of the conductive mica powder is less than 80 ml / 100g, more preferably 15ml / 100g-50ml / 100g.

[0011] Preferably, the conductive mica powder is attached to the powder coating primer composition by a thermal bonding process.

[0012] Preferably, the weight ratio of the conductive mica powder to the powder coating composition with a stable antistatic effect is 1-15wt%, more preferably 2-12wt%, and even more preferably 4-8wt%.

[0013] Preferably, the sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight of the powder coating composition with a stable antistatic effect, and more preferably 45-75wt%; and / or the weight part ratio of the thermosetting resin to the powder coating composition with a stable antistatic effect is 35-75wt%, and more preferably 40-70wt%.

[0014] Preferably, the thermosetting resin includes an epoxy resin, and the curing agent includes dicyandiamide or modified dicyandiamide or an anhydride curing agent or a polyester resin; or the thermosetting resin includes a carboxyl polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) or hydroxyalkylamide (HAA) or polybenzoic acid glycidyl ester; or the thermosetting resin includes a hydroxy polyester resin, and the curing agent includes an isocyanate compound.

[0015] Preferably, a cured coating with a stable antistatic effect is obtained by spraying the cured coating with a stable antistatic effect on a substrate, and then heating and curing the cured coating, wherein the surface resistance of the cured coating measured according to IEC 61340-2-3:2016 is stable at 10 5 -10 9 Ω, more preferably 10 5 -10 7 Ω; The surface resistance referred to in the entire application is based on the test standard DIN IEC 61340-2-3: 2016.

[0016] Preferably, the cured coating is white, has an L value greater than 85, an a value less than 5, and a b value less than 2.

[0017] It should be noted that the L value, a value and b value involved in this application are the L value, a value and b value data of the cured coating film detected by a Datacolor colorimeter. The L value, a value and b value data are from the Lab color mode, which is an international standard for measuring color formulated according to the Commission International Eclairage (CIE); the D50 particle size data involved is obtained by particle size distribution test using laser diffraction (for example, using Malvern Particle Size Analyzer 2000), and the test standard is ISO 13320-2009; the test standard for the oil absorption data involved is GB / T 5211.15-2014.

[0018] The present application proposes to use conductive mica powder with a mica powder core and a conductive material coated on the surface, and to attach at least part of the conductive mica powder to a powder coating base powder composition. The powder coating composition thus obtained has a stable and excellent antistatic effect after being sprayed and cured, and is particularly suitable for preparing coatings on the surfaces of related metal workpieces (such as electrical cabinets, electronic devices, etc.) containing electronic components with high requirements for electrostatic environments; it is also particularly suitable for preparing coatings on the surfaces of metal products that frequently come into contact with the human body, such as door handles. DETAILED DESCRIPTION

[0019] The embodiment of the present application proposes a powder coating composition with a stable antistatic effect, including a powder coating base composition and conductive mica powder, at least part of the conductive mica powder is attached to the powder coating base composition, and the powder coating base composition includes a thermosetting resin and a curing agent; wherein the conductive mica powder includes mica powder as a core, and the surface of the mica powder is coated with a conductive substance.

[0020] Preferably, in this embodiment, the resistivity of the conductive mica powder is >900 MΩ·cm, more preferably >1000 MΩ·cm.

[0021] Preferably, in this embodiment, the D50 particle size of the conductive mica powder is less than 60 microns, more preferably less than 50 microns, and more preferably 20-50 microns.

[0022] Preferably, in this embodiment, the oil absorption of the conductive mica powder is less than 80 ml / 100g, more preferably 15ml / 100g-50ml / 100g.

[0023] Preferably, in this embodiment, the conductive mica powder is attached to the powder coating primer composition by a thermal bonding process.

[0024] Preferably, in this embodiment, the weight ratio of the conductive mica powder to the powder coating composition with a stable antistatic effect is 1-15 wt %, more preferably 2-12 wt %, and even more preferably 4-8 wt %.

[0025] Preferably, in this embodiment, the sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight part of the powder coating composition with a stable antistatic effect, and more preferably 45-75wt%; and / or the weight part ratio of the thermosetting resin to the powder coating composition with a stable antistatic effect is 35-75wt%, and more preferably 40-70wt%.

[0026] Those skilled in the art can select appropriate thermosetting resins and curing agents according to the basic performance requirements of the actual coating, and this application does not impose any sole limitation on them during implementation.

[0027] Preferably, in this embodiment, the thermosetting resin includes epoxy resin, and the curing agent includes dicyandiamide or modified dicyandiamide or anhydride curing agent or polyester resin; or the thermosetting resin includes carboxyl polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) or hydroxyalkylamide (HAA) or polybenzoic acid glycidyl ester; or the thermosetting resin includes hydroxy polyester resin, and the curing agent includes isocyanate compound; All kinds of raw materials involved in this application can be directly purchased on the market, and the sources of raw materials are easy to obtain.

[0028] In the specific implementation of the present application, it is also possible to add known leveling agents, degassing agents, antioxidants, dispersants, fillers, pigments, stabilizers, curing accelerators, functional additives and / or other additives to the powder coating base powder composition. These are conventional technical choices of those skilled in the art; specifically, fillers and / or pigments can be, for example, aluminum hydroxide, barium sulfate, TiO2, etc., and it is recommended not to choose gray or black fillers and / or pigments.

[0029] When preparing the powder coating base powder composition of the present application, any known preparation process can be used for preparation; preferably, in this embodiment, the powder coating base powder composition is obtained by mixing, melt extrusion, and crushing. Of course, other known preparation processes can also be used to obtain the powder coating base powder composition of this embodiment, and the present application has no particular limitation on its preparation process.

[0030] Preferably, in this embodiment, at least part of the conductive mica powder is attached to the powder coating primer composition by a thermal bonding process, wherein the thermal bonding process can adopt any known thermal bonding (bonding) process, which is not particularly limited in this embodiment; preferably, in the thermal bonding process, the thermal bonding temperature is recommended to be set at 55-65°C, more preferably 58-63°C, and the thermal bonding time is recommended to be selected at 2-5 minutes.

[0031] Preferably, this embodiment further proposes a cured coating with a stable antistatic effect, wherein the cured coating with a stable antistatic effect as described above is sprayed on a substrate, and the cured coating is obtained after heating and curing, wherein the surface resistance of the cured coating measured according to IEC 61340-2-3:2016 is stable at 10 5 -10 9 Ω, more preferably 10 5 -10 7 Ω.

[0032] Preferably, in this embodiment, the cured coating is white, has an L value greater than 85, an a value less than 5, and a b value less than 2.

[0033] In order to verify the technical effect of the present application, the present application specifically conducted the following multiple groups of examples as raw materials for powder coating composition formulations for specific test performance comparison: Example 1: A powder coating composition with a stable antistatic effect, comprising 98wt% of a powder coating primer composition and 2wt% of a conductive mica powder (the brand is BC-M01 provided by Shanghai Junjiang New Materials, with a resistivity of >1000MΩ·cm, a D50 particle size of less than 50 microns, and an oil absorption of <80 ml / 100g); the conductive mica powder is compounded with the powder coating primer composition by a thermal bonding process, wherein in the thermal bonding process, the thermal bonding temperature is 58°C and the thermal bonding time is 2.5 minutes; In this embodiment 1, the powder coating primer composition is prepared according to the formula raw materials shown in Table 1 below:

[0034] Example 2: The rest of the technical solutions of Example 2 are the same as those of Example 1, except that, in Example 2, 96 wt % of the powder coating base powder composition and 4 wt % of the conductive mica powder are included.

[0035] Example 3: The rest of the technical solutions of Example 3 are the same as those of Example 1, except that, in Example 3, 92 wt % of the powder coating base powder composition and 8 wt % of the conductive mica powder are included.

[0036] Example 4: The rest of the technical solutions of Example 4 are the same as those of Example 1, except that, in Example 4, 90 wt % of the powder coating base powder composition and 10 wt % of the conductive mica powder are included.

[0037] Example 5: The rest of the technical solutions of Example 5 are the same as those of Example 1, except that, in Example 5, 88 wt % of the powder coating base powder composition and 12 wt % of the conductive mica powder are included.

[0038] Example 6: The rest of the technical solutions of Example 6 are the same as those of Example 1, except that, in Example 6, 99 wt % of the powder coating base composition and 1 wt % of the conductive mica powder are included.

[0039] Example 7: The rest of the technical solutions of Example 7 are the same as those of Example 1, except that, in Example 7, 99.2 wt % of the powder coating base composition and 0.8 wt % of the conductive mica powder are included.

[0040] Example 8: The rest of the technical solutions of Example 8 are the same as those of Example 1, except that, in Example 8, in the thermal bonding process, the thermal bonding temperature is 62° C., and the thermal bonding time is 2 minutes.

[0041] Example 9: The rest of the technical solutions of Example 9 are the same as those of Example 1, except that, in Example 9, in the thermal bonding process, the thermal bonding temperature is 55° C., and the thermal bonding time is 4 minutes.

[0042] Example 10: The rest of the technical solutions of Example 10 are the same as those of Example 1, except that, in Example 10, in the thermal bonding process, the thermal bonding temperature is 52° C., and the thermal bonding time is 5 minutes.

[0043] Example 11: The rest of the technical solutions of Example 11 are the same as those of Example 1, except that, in Example 11, the polyester resin brand in Example 1 is replaced by SJ3B provided by Anhui Shenjian.

[0044] Embodiment 12: The remaining technical solutions of Embodiment 12 are the same as those of Embodiment 1, except that, in Embodiment 12, the powder coating primer composition is prepared according to the formula raw materials shown in Table 2 below:

[0045] Comparative Example 1: The rest of the technical solutions of this comparative example 1 are the same as those of Example 1, except that, in this comparative example 1, the conductive mica powder in Example 1 is replaced by a coated effect pigment (brand ZPBF-318S from Changsha Zuxing New Materials Co., Ltd.).

[0046] Comparative Example 2: The rest of the technical solutions of this comparative example 2 are the same as those of Example 1, except that, in this comparative example 2, the conductive mica powder in Example 2 is replaced by NB free-bonding pearlescent powder PMW04101NB produced by Shanghai Jincheng.

[0047] Comparative Example 3: The rest of the technical solutions of Comparative Example 3 are the same as those of Example 1, except that, in Comparative Example 3, 99.5 wt % of the powder coating base powder composition and 0.5 wt % of the conductive mica powder are included.

[0048] The present application obtains the corresponding powder coating compositions according to the implementation schemes proposed in the above Examples 1-12 and Comparative Examples 1-3.

[0049] The powder coating compositions prepared in Examples 1-12 and Comparative Examples 1-3 were respectively used, and the same aluminum plate was selected as the substrate. Each powder coating composition was cured by baking heating, wherein the heating temperature was 200°C and the heating time was 15 minutes, to obtain a cured coating, and then the surface resistance and Lab test of the cured coating were performed. The test results are shown in Table 3 below.

[0050] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A powder coating composition having a stable antistatic effect, characterized in that: It comprises a powder coating base powder composition and conductive mica powder, at least part of which is attached to the powder coating base powder composition, and the powder coating base powder composition comprises a thermosetting resin and a curing agent; wherein the conductive mica powder comprises mica powder as a core, and the surface of the mica powder is coated with a conductive substance.

2. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The resistivity of the conductive mica powder is >900MΩ·cm, more preferably >1000MΩ·cm; the test standard for the resistivity is GB / T39978-2021.

3. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The D50 particle size of the conductive mica powder is less than 60 microns, more preferably less than 50 microns, and more preferably 20-50 microns.

4. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The oil absorption of the conductive mica powder is < 80 ml / 100g, more preferably 15ml / 100g-50ml / 100g.

5. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The conductive mica powder is attached to the powder coating primer composition through a thermal bonding process.

6. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The weight ratio of the conductive mica powder to the powder coating composition with a stable antistatic effect is 1-15wt%, more preferably 2-12wt%, and even more preferably 4-8wt%.

7. The powder coating composition with stable antistatic effect according to claim 1, characterized in that: The sum of the weight parts of the thermosetting resin and the curing agent accounts for 40-80wt% of the weight part of the powder coating composition with a stable antistatic effect, and is more preferably 45-75wt%; and / or the weight part of the thermosetting resin accounts for 35-75wt% of the weight part of the powder coating composition with a stable antistatic effect, and is more preferably 40-70wt%.

8. The powder coating composition with stable antistatic effect according to claim 1 or 7, characterized in that: The thermosetting resin includes epoxy resin, and the curing agent includes dicyandiamide or modified dicyandiamide or anhydride curing agent or polyester resin; or the thermosetting resin includes carboxyl polyester resin, and the curing agent includes triglycidyl isocyanurate (TGIC) or hydroxyalkylamide (HAA) or polybenzoic acid glycidyl ester; or the thermosetting resin includes hydroxy polyester resin, and the curing agent includes isocyanate compound.

9. A cured coating having a stable antistatic effect, characterized in that: The cured coating having a stable antistatic effect according to any one of claims 1 to 8 is sprayed on a substrate, and the cured coating is obtained after heating and curing, wherein the surface resistance of the cured coating measured according to IEC 61340-2-3:2016 is stably 10 5 -10 9 Ω, more preferably 10 5 -10 7 Ω; The surface resistance is based on the test standard DIN IEC 61340-2-3: 2016.

10. The cured coating with stable antistatic effect according to claim 9, characterized in that: The cured coating is white, has an L value greater than 85, an a value less than 5, and a b value less than 2.

Images