Non-ignition anti-static water-based epoxy explosion-proof coating

Abstract

The invention discloses a non-ignition anti-static water-based epoxy explosion-proof coating. The flame-retardant coating comprises the following components in parts by mass: 10-20 parts of a water-borne epoxy resin emulsion, 20-50 parts of a silicate inorganic cementing material, 0.5-3 parts of a carbon nanotube conductive agent, 5-15 parts of surface modified metal micro powder, 10-25 parts of misfire aggregate, 8-18 parts of a grade-A flame-retardant complexing agent, 0.5-2 parts of a silane coupling agent, 2-6 parts of nano silicon dioxide and 0.3-1.2 parts of a water-borne wetting dispersant, the misfire aggregate comprises dolomite and calcium carbonate composite particles, and the particle size range is 0.1-3mm. The anti-static water-based epoxy explosion-proof coating well overcomes the defects of construction, use and maintenance of a traditional dry powder thin explosion-proof floor coating, and can be applied to wall surfaces of sites with explosion-proof requirements and protection of related equipment and facilities at the same time.

Description

Technical Field

[0001] The present invention belongs to the field of special functional coatings, and particularly relates to a non-sparking and anti-static waterborne epoxy explosion-proof coating. Background Art

[0002] At present, the coating products in the market are applied to the industrial explosion-proof floor industry, which is a cement dry mortar material that must be combined with concrete during casting. Its defects mainly include the following points: first, dust will appear after long-term heavy use; second, the color is relatively single and not bright; third, the later repair is relatively troublesome and time-consuming; fourth, the electrical conductivity becomes weak due to the nature of dry powder inorganic substances in the later stage; fifth, if the explosion-proof surface layer about 3 mm is damaged, the aggregates in the original concrete may generate sparks during strong collision or friction; sixth, the corrosion resistance is poor; seventh, the waterproof / anti-permeability performance is poor; eighth, the stain resistance is poor, etc. Due to the combination method, it cannot be applied to more basic surfaces. Summary of the Invention

[0003] The present invention aims at the above problems and proposes a non-sparking and anti-static waterborne epoxy explosion-proof coating to solve the above problems.

[0004] The specific technical solution of the present invention is as follows:

[0005] A non-sparking and anti-static waterborne epoxy explosion-proof coating, comprising the following components in parts by mass: 10-20 parts of waterborne epoxy resin emulsion, 20-50 parts of silicate inorganic binder, 0.5-3 parts of carbon nanotube conductive agent, 5-15 parts of surface-modified metal micropowder, 10-25 parts of non-sparking aggregate, 8-18 parts of A-level flame retardant composite agent, 0.5-2 parts of silane coupling agent, 2-6 parts of nano-silica, 0.3-1.2 parts of waterborne wetting and dispersing agent; the non-sparking aggregate comprises dolomite and calcium carbonate composite particles, and the particle size range is 0.1-3 mm.

[0006] As a preference of the present invention, the carbon nanotube conductive agent is carboxylated single-walled carbon nanotubes with a length of 5-15 μm and a diameter-to-length ratio > 1000:1, and is used in combination with metal micropowder in a mass ratio of 1:3-1:8. Among them, the metal micropowder is coated with a silane coupling agent, and the particle size distribution D50 is 2-8 μm.

[0007] As a further preference of the present invention, the A-level flame retardant composite agent is compounded by aluminum hydroxide, ammonium polyphosphate and silicone flame retardant in a ratio of 4:3:1. Among them, the aluminum hydroxide is nano-sized, and the specific surface area ≥ 30 m 2 / g, and the ammonium polyphosphate is coated with a zirconium phosphate layer.

[0008] As a further preference of the present invention, the mass ratio of the aqueous epoxy resin emulsion to the silicate inorganic cementitious material is 1:0.6 - 1:0.8, wherein the silicate is a composite system of modified lithium water glass and wollastonite, the modulus of the modified lithium water glass is 2.8 - 4.8, and the aspect ratio of the wollastonite powder is >10:1.

[0009] As a further preference of the present invention, after the coating is cured, a continuous and dense coating with a thickness of 0.5 - 3 mm is formed, the surface resistivity is stable at 1×10 6 -10 9 Ω, the triboelectrification voltage < 100 V, the combustion performance reaches the GB8624 A2 level standard, and the compressive strength ≥ 30 MPa.

[0010] As a further preference of the present invention, when applying the coating, a three-layer system of primer - intermediate coat - top coat is adopted, wherein the viscosity of the primer is 800 - 1200 mPa·s, the viscosity of the top coat is 3000 - 5000 mPa·s, and each coating layer is combined through the dual actions of chemical bonding and mechanical anchoring.

[0011] As a further preference of the present invention, the coating is applicable to substrates such as concrete, metal, wood, and ceramic tiles, the bonding strength with the substrate ≥ 3.5 MPa, and the water permeability < 0.1 mL / h·m 2 .

[0012] As a further preference of the present invention, the method for preparing the coating includes: first, ultrasonically dispersing carbon nanotubes and metal micro - powder in an ethanol / water mixed medium for 30 - 60 min, and then pre - reacting with the silicate material to form a conductive network; the flame - retardant component is subjected to ball - milling activation treatment, and is blended with the resin emulsion step by step while controlling the shear rate at 800 - 1500 rpm.

[0013] As a further preference of the present invention, the VOC content in the coating system < 50 g / L, the heavy metal content complies with the GB24408 - 2009 standard, and the free formaldehyde released during the curing process < 0.05 mg / m 3 .

[0014] As a further preference of the present invention, the coating contains 0.2 - 0.8 parts of organosilicon - modified zinc oxide as a wear - resistant enhancer, which is prepared by the sol - gel method, the specific surface area ≥ 50 m 2 / g, and forms a three - dimensional protection network in synergy with the silane coupling agent.

[0015] The antistatic water - borne epoxy explosion - proof coating of this product well solves the construction, use, and maintenance drawbacks of traditional dry - powder thin - type explosion - proof floor coatings, and can also be used for protecting the walls and related equipment and facilities in places with explosion - proof requirements.

[0016] The coating system of the present invention comprises core components such as waterborne epoxy resin emulsion, silicate inorganic cementitious material, carbon nanotube conductive agent, non-sparking aggregate, etc., and realizes the following characteristics through synergistic effects:

[0017] 1. The surface resistivity is stabilized at 10 6 -10 9 Ω, and the triboelectric voltage < 100V;

[0018] 2. The combustion performance reaches the GB8624 A2 level standard;

[0019] 3. The compressive strength ≥ 30MPa, and the water permeability < 0.1mL / h·m 2 ;

[0020] 4. The environmental protection indicators comply with the GB24408-2009 standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The following shows the preparation flow chart of the coating of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, the present invention will be further described through specific examples.

[0023] Example 1

[0024] A non-sparking antistatic waterborne epoxy explosion-proof coating comprises the following components in parts by mass: 15 parts of waterborne epoxy resin emulsion, 30 parts of silicate inorganic cementitious material, 2 parts of carbon nanotube conductive agent, 10 parts of surface-modified metal micro-powder, 12 parts of non-sparking aggregate, 12 parts of A-level flame retardant composite agent, 1.5 parts of silane coupling agent, 4 parts of nano-silica, and 1 part of waterborne wetting and dispersing agent; the non-sparking aggregate comprises dolomite and calcium carbonate composite particles, and the particle size range is 0.9mm.

[0025] In this example, the carbon nanotube conductive agent is carboxylated single-walled carbon nanotubes with a length of 10μm and an aspect ratio > 1000:1, and is used in combination with the metal micro-powder at a mass ratio of 1:4. Among them, the metal micro-powder is coated with a silane coupling agent, and the particle size distribution D50 is 6μm.

[0026] In this example, the A-level flame retardant composite agent is compounded by aluminum hydroxide, ammonium polyphosphate and organosilicon flame retardant in a ratio of 4:3:1. Among them, the aluminum hydroxide is nano-sized, and the specific surface area ≥ 30m 2 / g, and the ammonium polyphosphate is coated with a zirconium phosphate layer.

[0027] In this example, the mass ratio of the waterborne epoxy resin emulsion to the silicate inorganic cementitious material is 1:0.7. Among them, the silicate is a composite system of modified lithium water glass and wollastonite. The modified lithium water glass has a modulus of 4, and the aspect ratio of the wollastonite powder > 10:1.

[0028] In this embodiment, after the coating is cured, a continuous and dense coating with a thickness of 2 mm is formed, the surface resistivity is stable at 1×10 6 -10 9 Ω, the triboelectrification voltage < 100 V, the combustion performance reaches the GB8624 A2 level standard, and the compressive strength ≥ 30 MPa.

[0029] In this embodiment, a three-layer system of primer - intermediate coat - top coat is adopted during the coating construction. Among them, the viscosity of the primer is 1000 mPa·s, and the viscosity of the top coat is 4000 mPa·s. Each coating layer is combined through the dual effects of chemical bonding and mechanical anchoring.

[0030] In this embodiment, the coating is applicable to substrates such as concrete, metal, wood, and ceramic tiles. The bonding strength with the substrate ≥ 3.5 MPa, and the water permeability < 0.1 mL / h·m 2 .

[0031] The coating preparation method of this embodiment includes: first, ultrasonically disperse carbon nanotubes and metal micro - powder in an ethanol / water mixed medium for 30 - 60 min, and then pre - react with silicate materials to form a conductive network; the flame - retardant component is subjected to ball - milling activation treatment, and is blended with the resin emulsion step by step while controlling the shear rate at 1000 rpm.

[0032] In this embodiment, the VOC content in the coating system < 50 g / L, and the heavy metal content complies with

[0033] the GB24408 - 2009 standard, and the free formaldehyde released during the curing process < 0.05 mg / m 3 .

[0034] In this embodiment, the coating contains 0.4 parts of organosilicon - modified zinc oxide as a wear - resistant enhancer, which is prepared by the sol - gel method, and the specific surface area ≥ 50 m 2 / g, and forms a three - dimensional protection network in synergy with the silane coupling agent.

[0035] Example 2: High - conductivity explosion - proof coating (applicable to the floor of flammable and explosive workshops)

[0036] Formulation (parts by mass): aqueous epoxy resin emulsion: 18 parts, modified lithium water glass / wollastonite composite cementitious material: 45 parts (modulus 3.5, aspect ratio of wollastonite 12:1), carboxylated single - walled carbon nanotubes:

[0037] 2.5 parts (length 10 μm, compounded with silane - coated iron powder at a ratio of 1:5), dolomite / calcium carbonate non - sparking aggregate: 22 parts (particle size 0.5 - 2 mm), Class A flame - retardant: 15 parts (aluminum hydroxide: ammonium polyphosphate:

[0038] Silicone = 4:3:1), silane coupling agent: 1.5 parts, nano-silica: 5 parts.

[0039] Preparation method

[0040] 1. Ultrasonically disperse carbon nanotubes and iron powder in ethanol / water (1:3) for 40 min to form a conductive paste;

[0041] 2. After the flame retardant components are activated by ball milling, they are mixed step by step with the resin emulsion at 1200 rpm;

[0042] 3. Add non-sparking aggregate and silicate cementitious material, and control the viscosity to 1000 mPa·s for the primer and 4000 mPa·s for the topcoat;

[0043] 4. Coating on the concrete substrate to form a 2-mm coating, with a surface resistivity of 5×10 7 Ω and a compressive strength of 35 MPa after curing.

[0044] Example 3: High flame-retardant explosion-proof coating (for metal pipelines in chemical plants)

[0045] Formula (parts by mass): Waterborne epoxy resin emulsion: 15 parts, silicate cementitious material: 30 parts (modulus 4.0, wollastonite aspect ratio 15:1), carboxylated single-walled carbon nanotubes: 1.0 part (composite with copper powder at 1:8), non-sparking aggregate: 18 parts (particle size 1-3 mm), Class A flame retardant: 18 parts (nano-aluminum hydroxide specific surface area 35 m 2 / g, polyphosphate-coated zirconium phosphate layer), organosilicon-modified zinc oxide: 0.6 part (specific surface area 60 m 2 / g).

[0046] Performance data are as follows:

[0047] 1. Combustion test: The vertical combustion damage length < 50 mm, and the flue gas toxicity level is AQ2;

[0048] 2. Bonding strength: 4.2 MPa (Q235 steel plate substrate);

[0049] 3. VOC content: 38 g / L, free formaldehyde not detected.

[0050] Example 4: Environmentally friendly wear-resistant explosion-proof coating (for underground garage floors)

[0051] Formula (parts by mass): Waterborne epoxy resin emulsion: 12 parts, silicate cementitious material: 25 parts (modulus 2.8, wollastonite aspect ratio 8:1), carboxylated single-walled carbon nanotubes: 0.8 part (composite with aluminum powder at 1:3), non-sparking aggregate: 15 parts (particle size 0.1-1 mm), organosilicon-modified zinc oxide: 0.3 part, waterborne wetting and dispersing agent: 0.9 part.

[0052] The construction process is as follows:

[0053] 1. The primer (viscosity 800 mPa·s) penetrates the base material, and 50% aggregate is added to the intermediate coat to enhance the strength;

[0054] 2. The top coat (viscosity 5000 mPa·s) incorporates nano-silica to enhance wear resistance;

[0055] 3. The water permeability after curing is 0.05 mL / h·m 2 , and the surface resistivity fluctuation is <10% after 5000 friction cycles.

[0056] As can be seen from Figure 1 , the preparation methods of Examples 2, 3, and 4 are as follows:

[0057] I. Pretreatment of raw materials

[0058] 1. Preparation of the conductive network precursor

[0059] (1) Mix carboxylated single-walled carbon nanotubes (Claim 2) and surface-modified metal micropowders in a mass ratio of 1:3 - 1:8, and add an ethanol / water mixture (volume ratio 1:1 - 1:3);

[0060] (2) Ultrasonic dispersion: Ultrasonically treat for 30 - 60 minutes at 40 - 60 °C with a frequency of 40 kHz to form a uniformly dispersed conductive paste.

[0061] 2. Activation treatment of the flame retardant

[0062] (1) Mix the Class A flame retardant composite agent (Claim 3: aluminum hydroxide, ammonium polyphosphate, and silicone flame retardant in a ratio of 4:3:1) and nano-silica;

[0063] (2) Ball milling activation: Under the protection of inert gas, use a planetary ball mill (rotation speed 300 - 500 rpm) to ball mill for 2 - 4 hours to obtain an activated flame retardant powder with a specific surface area ≥ 50 m 2 / g.

[0064] 3. Modification of the silicate cementitious material

[0065] (1) Mix the modified lithium water glass (modulus 2.8 - 4.8) and wollastonite powder (aspect ratio > 10:1) according to the ratio of Claim 4;

[0066] (2) Add a silane coupling agent (Claim 1) and stir at 500 - 800 rpm for 15 minutes to form a pre-reacted cementitious system.

[0067] II. Main slurry mixing process

[0068] 1. Construction of the conductive network

[0069] (1) Mix the pretreated conductive paste (carbon nanotube - metal micropowder) with the silicate cementitious material;

[0070] (2) Pre - reaction: Stir at a low speed (200 - 400 rpm) for 30 minutes at 25 - 35 °C to form a three - dimensional interpenetrating network between the conductive agent and the silicate.

[0071] 2. Composite of resin - flame retardant system

[0072] (1) Mix the aqueous epoxy resin emulsion (Claim 1) and the activated flame - retardant powder step by step:

[0073] (2) First step: Pre - disperse 50% of the flame retardant and the resin emulsion at 800 - 1000 rpm for 10 minutes; (3) Second step: Add the remaining flame retardant and organosilicon - modified zinc oxide (Claim 10), increase the shear rate to 1200 - 1500 rpm, and continue for 15 minutes.

[0074] 3. Blending of aggregate and functional additives

[0075] (1) Add the non - sparking aggregate (dolomite / calcium carbonate composite particles, 0.1 - 3 mm), aqueous wetting and dispersing agent, and nano - silica in sequence;

[0076] (2) Gradient mixing: Mix at a low speed (400 rpm) for 5 minutes to avoid aggregate crushing; mix at a high speed (1000 rpm) for 10 minutes to ensure uniform dispersion.

[0077] III. Construction and curing control

[0078] 1. Layered construction of the coating (Claim 6)

[0079] (1) Primer coat: Adjust the viscosity to 800 - 1200 mPa·s, spray or roll - coat on the substrate surface, with a thickness of 0.1 - 0.3 mm;

[0080] (2) Intermediate coat: Add 50% non - sparking aggregate, with a viscosity of 1500 - 2000 mPa·s, scrape - coat to form a transition layer of 0.5 - 1 mm;

[0081] (3) Top coat: Adjust the viscosity to 3000 - 5000 mPa·s, incorporate nano - silica (Claim 1), and form a dense layer of 0.3 - 0.5 mm after spraying.

[0082] 2. Curing and cross - linking

[0083] (1) Cure for 24 - 48 hours in an environment with a temperature of 20 - 30 °C and a humidity ≤ 70%;

[0084] (2) Form a chemical bond with the substrate through a silane coupling agent (Claim 1), and at the same time, the aggregate particles produce a mechanical anchoring effect (Claim 6).

[0085] IV. Key process control points

[0086] 1. Conductive network stability: The mass ratio error of carbon nanotubes to metal micro-powders ≤ ±5%, and the resistivity of the slurry after ultrasonic dispersion < 100 Ω·cm;

[0087] 2. Environmental protection index control (Claim 9):

[0088] (1) The whole mixing stage is airtight, the temperature ≤ 40°C, reducing the VOC volatilization;

[0089] (2) The detected value of free formaldehyde after curing < 0.05 mg / m 3 (verified by gas chromatography);

[0090] 3. Flame retardant dispersion uniformity: The D90 particle size of the flame retardant powder after ball milling ≤ 5 μm, ensuring the formation of a continuous carbon layer during combustion.

[0091] V. Equipment and parameter examples

[0092]

[0093]

[0094] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A non-inflammable anti-static water-based epoxy explosion-proof coating, characterized in that: The invention comprises the following components in parts by weight: 10-20 parts of waterborne epoxy resin emulsion, 20-50 parts of silicate inorganic gelling material, 0.5-3 parts of carbon nanotube conductive agent, 5-15 parts of surface modified metal micropowder, 10-25 parts of non-pyrophoric aggregate, 8-18 parts of Class A flame retardant composite agent, 0.5-2 parts of silane coupling agent, 2-6 parts of nano silicon dioxide and 0.3-1.2 parts of waterborne wetting dispersant; the non-pyrophoric aggregate comprises composite particles of dolomite and calcium carbonate with a particle size range of 0.1-3 mm.

2. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The carbon nanotube conductive agent is a carboxylated single-walled carbon nanotube with a length of 5-15 μm and a diameter-to-length ratio of >1000:1, and is used in combination with metal micropowder at a mass ratio of 1:3-1:8, wherein the metal micropowder is coated with a silane coupling agent and has a particle size distribution D50 of 2-8 μm.

3. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The Class A flame retardant composite is prepared by mixing aluminum hydroxide, ammonium polyphosphate and organic silicon flame retardant in a ratio of 4:3:1, wherein the aluminum hydroxide is nano-processed and has a specific surface area of ​​≥30m 2 / g, the ammonium polyphosphate is coated with a zirconium phosphate layer.

4. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The mass ratio of the waterborne epoxy resin emulsion to the silicate inorganic gelling material is 1:0.6-1:0.8, wherein the silicate is a composite system of modified lithium water glass and wollastonite, the modulus of the modified lithium water glass is 2.8-4.8, and the diameter-length ratio of the wollastonite powder is greater than 10:

1.

5. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: After curing, the coating forms a continuous and dense coating of 0.5-3 mm, and the surface resistivity is stable at 1×10 6 -10 9 Ω, friction electrification voltage <100V, combustion performance reaches GB8624A2 standard, compressive strength ≥30MPa.

6. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The coating is constructed using a three-layer system of primer, mid-coat and topcoat, wherein the primer viscosity is 800-1200 mPa·s, the topcoat viscosity is 3000-5000 mPa·s, and the coatings are bonded together by chemical bonding and mechanical anchoring.

7. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The coating is suitable for concrete, metal, wood and tile substrates, with a bonding strength of ≥3.5MPa and a water permeability of <0.1mL / h·m 2 .

8. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The coating preparation method comprises: firstly ultrasonically dispersing carbon nanotubes and metal powder in an ethanol / water mixed medium for 30-60 minutes, and then pre-reacting with a silicate material to form a conductive network; the flame retardant component is activated by ball milling, and then mixed with the resin emulsion in steps and the shear rate is controlled at 800-1500rpm.

9. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The VOC content of the coating system is less than 50g / L, the heavy metal content meets the GB24408-2009 standard, and the free formaldehyde released during the curing process is less than 0.05mg / m 3 .

10. The non-inflammable anti-static water-based epoxy explosion-proof coating according to claim 1, characterized in that: The coating contains 0.2-0.8 parts of organosilicon-modified zinc oxide as a wear-resistant enhancer, which is prepared by a sol-gel method and has a specific surface area of ​​≥50m 2 / g, synergistically forming a three-dimensional protective network with silane coupling agent.

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