阅读说明：本技术 一种无溶剂环氧富锌涂料 (Solvent-free epoxy zinc-rich coating ) 是由 刘瑞清 欧小琼 张博晓 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种无溶剂环氧富锌涂料,属于涂料领域。该无溶剂环氧富锌涂料选用改性的E51型环氧树脂作为组分,同时优选特定的水性胺固化剂,制得产品可实现极低的VOCs含量(小于30g/L),固含量≥97％,可在高湿(湿度大于85％)条件下实现较快的干燥,拓宽了水性涂料的使用范围；所述产品可根据不同的环境用水进行调节粘度,无需引入有机稀释剂,进一步降低VOCs的排放,且具备优异的防腐性能、附着力、耐水性和施工性,可广泛用于钢结构、桥梁、集装箱和石化等领域。本发明还公开了所述产品的制备方法,该方法操作步骤简单,可实现工业化大规模生产。(The invention discloses a solvent-free epoxy zinc-rich coating, and belongs to the field of coatings. The solvent-free epoxy zinc-rich paint adopts modified E51 epoxy resin as a component, and simultaneously selects a specific aqueous amine curing agent, so that the prepared product can realize extremely low VOCs content (less than 30g/L), has a solid content of more than or equal to 97 percent, can realize faster drying under the condition of high humidity (the humidity is more than 85 percent), and widens the application range of the aqueous paint; the product can adjust viscosity according to different environmental waters, need not to introduce organic diluent, further reduces VOCs's emission, and possesses excellent corrosion resisting property, adhesive force, water proofness and constructability, can extensively be used for fields such as steel construction, bridge, container and petrochemical industry. The invention also discloses a preparation method of the product, which has simple operation steps and can realize industrialized large-scale production.)

1. The solvent-free epoxy zinc-rich coating is characterized by comprising a component A and a component B, wherein the mass ratio of the component A to the component B is (5-15): 1;

the component A comprises the following components in parts by weight: 7-20 parts of modified epoxy resin, 0.2-1 part of molecular sieve, 0.1-1 part of defoaming agent, 0.2-2 parts of dispersing agent, 55-80 parts of zinc powder and 0.5-2.5 parts of anti-settling agent a;

the component B comprises the following components in parts by weight: 3-10 parts of water-based amine curing agent, 0.1-0.5 part of catalyst, 0.5-2.5 parts of flash rust inhibitor and 0.1-1 part of anti-settling agent b;

the modified epoxy resin is E51 type epoxy resin modified by an emulsifier.

2. The solventless epoxy zinc rich coating of claim 1 wherein the modified epoxy resin comprises the following components in parts by weight: 90 parts of E51 type epoxy resin, 2 parts of emulsifier a and 8 parts of emulsifier b; the emulsifier a comprises at least two of Tween 80, span-80, NP-10, NP-15, PEG-800 and PEG-1000; the emulsifier b is a reactive epoxy resin emulsifier.

3. The solventless epoxy zinc rich coating of claim 2 wherein the modified epoxy resin is prepared by a process comprising: placing the E51 epoxy resin in a nitrogen environment, heating while adding the emulsifier a and the emulsifier b until the mixture is uniform, and then dispersing at a high speed until the particle size is less than 5 mu m to obtain the modified epoxy resin; the heating temperature is 50-70 ℃; preferably, the stirring and high-speed dispersing speed is 1000-2000 r/min.

4. The solventless epoxy zinc rich coating of claim 1 comprising at least one of the following features (a) - (f):

(a) the molecular sieve comprises at least one of a 3A type molecular sieve and a 4A type molecular sieve;

(b) the defoaming agent comprises at least one of organic silicon, mineral oil and polymer defoaming agent;

(c) the dispersant is an anhydrous dispersant; the dispersant comprises an amphiphilic organic polymer dispersant; the solid content of the dispersant is more than or equal to 60 percent.

(d) The mesh number of the zinc powder is more than or equal to 800 meshes;

(e) the catalyst comprises a small molecule polyamine curing agent;

(f) the flash rust inhibitor is an organic flash rust inhibitor.

5. The solventless epoxy zinc rich coating of claim 1 wherein the aqueous amine curing agent comprises at least one of an epoxy amine adduct, a fatty amine cardanol modified amine, IPDA, a phenolic amine.

6. The solventless epoxy zinc rich coating of claim 1 wherein the anti-settling agent a is a hydrophobic anti-settling agent; preferably, the anti-settling agent a comprises at least one of bentonite, fumed silica, polyamide sodium and polyurea.

7. The solventless epoxy zinc rich coating of claim 1 wherein the anti-settling agent b comprises at least one of an organobentonite, a fumed silica, a sodium polyamide, a polyurea, an attapulgite.

8. The method for preparing the solvent-free epoxy zinc-rich paint according to any one of claims 1 to 7, comprising the following steps:

(1) adding an anti-settling agent a, a dispersing agent and a molecular sieve into the modified epoxy resin while stirring, and dispersing at a high speed to form slurry; the temperature of the slurry is maintained to be less than or equal to 40 ℃ in the stirring and high-speed dispersing process through condensation;

(2) adding zinc powder into the slurry obtained in the step (1), dispersing and refining the particles, then adding a defoaming agent, and uniformly dispersing for the second time to obtain a component A;

(3) uniformly mixing and stirring the water-based amine curing agent, the flash rust inhibitor, the catalyst and the anti-settling agent B to obtain the component B;

(4) and mixing and stirring the component A and the component B uniformly to obtain the solvent-free epoxy zinc-rich coating.

9. The method for preparing the solventless epoxy zinc-rich paint according to claim 7, comprising at least one of the following technical features (g) to (i):

(g) the stirring and high-speed dispersing speed of the step (1) is 2000-3000 r/min, and the time is 20-40 min;

(h) the dispersing speed in the step (2) is 1000-2000 r/min, and the time is 15-30 min; the rate of the secondary dispersion is 600-1000 r/min, and the time is 10-20 min;

(i) and (3) stirring at the speed of 1000-1500 r/min for 10-20 min.

10. The method for preparing the solventless epoxy zinc-rich paint according to claim 7, wherein the size of the slurry particles after the dispersion refinement in the step (2) is less than or equal to 60 μm.

Technical Field

The invention relates to the field of coatings, in particular to a solvent-free epoxy zinc-rich coating.

Background

The epoxy zinc-rich primer plays a very important role in the field of heavy corrosion prevention, but the traditional oily epoxy zinc-rich paint causes great harm to the environment due to high VOCs content, and belongs to dangerous chemicals. Compared with oily epoxy zinc-rich paint, the waterborne epoxy zinc-rich paint has the advantage of environmental protection, has almost the same performance as oily paint, and is one of the optimal choices for replacing oily epoxy zinc-rich paint.

However, compared with the common water-based paint, the water-based epoxy zinc-rich paint still has relatively high solvent content because the zinc powder-containing component cannot contain water and needs a certain amount of solvent to reduce the viscosity of the resin, and although the environment-friendly requirement can be met, the aim of reducing the content of VOCs (volatile organic compounds) to be less than 50g/L or even lower is difficult to achieve. Based on the technical problems, CN112500764A discloses a solvent-free epoxy zinc-rich anticorrosive paint and a preparation method thereof, which effectively solve the technical problem that the VOCs content of an oily or common water-based epoxy zinc-rich paint is higher than 50g/L, and simultaneously solve the defect that the viscosity of the solvent-free paint is difficult to construct, thereby realizing the technical effect of thin coating, but simultaneously, because the viscosity of the product is low, thick coating is difficult to realize, the advantage that the solvent-free paint can realize thick coating in the field of heavy corrosion prevention does not exist; in addition, the solvent-free epoxy zinc-rich coating has a limited construction range due to the limitation of viscosity, and cannot effectively meet the construction requirements of different temperatures and different humidities; moreover, in order to meet the construction requirements, if the construction viscosity is adjusted, the epoxy zinc-rich paint needs to be diluted by an organic solvent, which is equivalent to the additional introduction of VOC, and the advantage of low content of VOCs of the solvent-free epoxy zinc-rich paint is difficult to be really reflected.

Disclosure of Invention

Based on the defects of the prior art, the invention aims to provide a solvent-free epoxy zinc-rich coating which can realize extremely low content of VOCs (less than 30g/L) and dry quickly under high-humidity conditions; the paint has high wettability to a base material, has a self-emulsifying function, can be diluted and viscosity adjusted by water according to different construction environments and different requirements, has high construction feasibility, and does not need to add an organic diluent for adjusting viscosity like the traditional solvent-free paint.

In order to achieve the purpose, the invention adopts the technical scheme that:

a solvent-free epoxy zinc-rich coating comprises a component A and a component B, wherein the mass ratio of the component A to the component B is (5-15): 1;

the component A comprises the following components in parts by weight: 7-20 parts of modified epoxy resin, 0.2-1 part of molecular sieve, 0.1-1 part of defoaming agent, 0.2-2 parts of dispersing agent, 55-80 parts of zinc powder and 0.5-2.5 parts of anti-settling agent a;

the component B comprises the following components in parts by weight: 3-10 parts of water-based amine curing agent, 0.1-0.5 part of catalyst, 0.5-2.5 parts of flash rust inhibitor and 0.1-1 part of anti-settling agent b;

the modified epoxy resin is E51 type epoxy resin modified by an emulsifier.

The E51 epoxy resin has the advantages of strong adhesiveness, corrosion resistance, high strength and the like, and the prepared product has better wettability and dispersibility compared with the common epoxy resin after being modified by the emulsifier.

The solvent-free epoxy zinc-rich paint disclosed by the invention selects modified E51 type epoxy resin as a component, and simultaneously selects a specific aqueous amine curing agent preferentially, so that the prepared product can realize extremely low VOCs content (less than 30g/L), has a solid content of more than or equal to 97%, can realize faster drying under the condition of high humidity (the humidity is more than 85%), and widens the application range of the aqueous paint; the product can adjust viscosity according to different environmental waters, need not to introduce organic diluent, further reduces VOCs's emission, and possesses excellent corrosion resisting property, adhesive force, water proofness and constructability, can extensively be used for fields such as steel construction, bridge, container and petrochemical industry.

Preferably, the modified epoxy resin comprises the following components in parts by weight: 90 parts of E51 type epoxy resin, 2 parts of emulsifier a and 8 parts of emulsifier b; the emulsifier a comprises at least two of Tween 80, span-80, NP-10, NP-15, PEG-800 and PEG-1000; the emulsifier b is a reactive epoxy resin emulsifier.

Due to the addition of the emulsifier, the modified E51 epoxy resin has amphipathy, can well disperse and coat zinc powder, and has a self-emulsifying function, and the prepared solvent-free coating can be diluted by water according to actual needs, so that the workability of the coating is further improved, and the construction range is expanded.

More preferably, the viscosity of the emulsifier b at 50 ℃ is less than or equal to 3000cP, the pH value is greater than or equal to 5, the single amount of epoxy is 10000-50000, and the melting point is less than or equal to 50 ℃.

More preferably, the preparation method of the modified epoxy resin comprises the following steps: placing the E51 epoxy resin in a nitrogen environment, heating while adding the emulsifier a and the emulsifier b until the mixture is uniform, and then dispersing at a high speed until the particle size is less than 5 mu m to obtain the modified epoxy resin; the heating temperature is 50-70 ℃.

More preferably, the stirring and high-speed dispersing speed is 1000-2000 r/min.

Preferably, the molecular sieve comprises at least one of a type 3A molecular sieve, a type 4A molecular sieve.

Preferably, the defoamer comprises at least one of silicone, mineral oil, polymeric defoamer.

More preferably, the polymeric antifoaming agent is an organic polymeric antifoaming agent that is hydrophobic and has a foam breaking function.

Preferably, the dispersant is a water-free dispersant; more preferably, the dispersant comprises an amphiphilic organic polymeric dispersant.

More preferably, the solid content of the dispersant is 60% or more.

Preferably, the mesh number of the zinc powder is more than or equal to 800 meshes.

Preferably, the anti-settling agent a is a hydrophobic anti-settling agent; more preferably, the anti-settling agent a comprises at least one of bentonite, fumed silica, polyamide sodium and polyurea.

Preferably, the aqueous amine curing agent comprises at least one of epoxy amine adduct, fatty amine cardanol modified amine, IPDA and phenolic amine.

The type of the water-based amine curing agent can still be normally used after being diluted by water, and the water can be added for viscosity adjustment according to the actual construction condition after the water-based amine curing agent is used for preparing the coating.

The catalyst comprises a small molecule polyamine curing agent.

The catalyst can accelerate the reaction of the epoxy resin and the water-based amine curing agent, and the molding is faster.

Preferably, the anti-settling agent b comprises at least one of organic bentonite, fumed silica, polyamide sodium, polyurea and attapulgite.

Preferably, the flash rust inhibitor is an organic flash rust inhibitor.

The invention also aims to provide a preparation method of the solvent-free epoxy zinc-rich paint, which comprises the following steps:

(1) adding an anti-settling agent a, a dispersing agent and a molecular sieve into the modified epoxy resin while stirring, and dispersing at a high speed to form slurry; the temperature of the slurry is maintained to be less than or equal to 40 ℃ in the stirring and high-speed dispersing process through condensation;

(2) adding zinc powder into the slurry obtained in the step (1), dispersing and refining the particles, then adding a defoaming agent, and uniformly dispersing for the second time to obtain a component A;

(3) uniformly mixing and stirring the water-based amine curing agent, the flash rust inhibitor, the catalyst and the anti-settling agent B to obtain the component B;

(4) and mixing and stirring the component A and the component B uniformly to obtain the solvent-free epoxy zinc-rich coating.

The preparation method of the solvent-free epoxy zinc-rich coating has simple operation steps and can realize industrial large-scale production.

Preferably, the stirring and high-speed dispersing speed in the step (1) is 2000-3000 r/min, and the time is 20-40 min.

Preferably, the dispersing speed in the step (2) is 1000-2000 r/min, and the time is 15-30 min; the rate of the secondary dispersion is 600-1000 r/min, and the time is 10-20 min.

More preferably, the size of the slurry particles after dispersion refinement is less than or equal to 60 mu m.

Preferably, the stirring speed in the step (3) is 1000-1500 r/min, and the time is 10-20 min.

Under the speed and time of the dispersion and stirring, the particle size and the dispersion degree of each component in the matrix can be ensured, so that the texture of the final product is uniformly dispersed.

The solvent-free epoxy zinc-rich coating has the beneficial effects that the solvent-free epoxy zinc-rich coating adopts modified E51 epoxy resin as a component, and simultaneously selects a specific water-based amine curing agent, so that the prepared product can realize extremely low VOCs content (less than 30g/L), the solid content is more than or equal to 97 percent, the quick drying can be realized under the condition of high humidity (the humidity is more than 85 percent), and the application range of the water-based coating is widened; the product can adjust viscosity according to different environmental waters, need not to introduce organic diluent, further reduces VOCs's emission, and possesses excellent corrosion resisting property, adhesive force, water proofness and constructability, can extensively be used for fields such as steel construction, bridge, container and petrochemical industry. The invention also provides a preparation method of the product, which has simple operation steps and can realize industrialized large-scale production.

Detailed Description

In order to better illustrate the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to specific examples and comparative examples, which are intended to be understood in detail, but not intended to limit the invention. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention. The experimental reagents and instruments designed for the practice of the present invention and the comparative examples are common reagents and instruments unless otherwise specified.

The reagents used in the examples of the invention were as follows:

modified epoxy resin: comprises 90 parts of E51 type epoxy resin, 2 parts of emulsifier a and 8 parts of emulsifier b; the emulsifier a comprises 803 parts of span, NP-105 parts of and PEG-8002 parts of which are all common commercial products; the emulsifier b is a reactive epoxy resin emulsifier.

The viscosity of the emulsifier b at 50 ℃ is less than or equal to 3000cP, the pH value is greater than or equal to 5, the single amount of epoxy is 10000-50000, and the melting point is less than or equal to 50 ℃;

the preparation method of the modified epoxy resin comprises the following steps: placing the E51 epoxy resin in a reaction kettle in a nitrogen-gas-introduced environment, adding the emulsifier a and the emulsifier b while heating in an oil bath until the mixture is uniform, and then dispersing at a high speed until the particle size is less than 5 mu m to obtain the modified epoxy resin; the heating temperature is 60 ℃; the stirring and high-speed dispersion speed is 1500 r/min.

Molecular sieve: a type 4A molecular sieve;

defoaming agent: TEGO 901W, produced by winning chemical companies;

dispersing agent: 1728A, 60% of solid content, produced by Shanghai deep bamboo chemical company;

zinc powder: 1000 mesh zinc powder; a common commercial product;

anti-settling agent a: hydrophobic silica type 812, produced by pioneer chemical company;

aqueous amine curing agent: 838 type waterborne amine curing agent, available from Union Chemicals;

catalyst: 2950 catalyst, available from hensimei corporation;

flash rust inhibitor: rebao 90 flash rust inhibitors, manufactured by Rebao corporation, USA;

anti-settling agent b: SD-2 bentonite anti-settling agent; manufactured by Haimines corporation;

examples 1 to 5

In the embodiment of the solvent-free epoxy zinc-rich coating, the raw materials and the use weight ratio of the product are shown in the table 1;

the preparation method of the product comprises the following steps:

(1) placing the modified epoxy resin in a reaction kettle with a condensation cycle, adding the anti-settling agent a, the dispersing agent and the molecular sieve while stirring, and dispersing at a high speed to form slurry; the temperature of the slurry is maintained to be less than or equal to 40 ℃ in the stirring and high-speed dispersing process through condensation; the stirring and high-speed dispersion speed is 2500r/min, and the time is 30 min;

(2) adding zinc powder into the slurry obtained in the step (1), dispersing and refining the particles to be less than or equal to 60 mu m, and then adding a defoaming agent, and uniformly dispersing for the second time to obtain a component A; the speed of the dispersion is 1500r/min, and the time is 20 min; the rate of the secondary dispersion is 800r/min, and the time is 15 min;

(3) uniformly mixing and stirring the water-based amine curing agent, the flash rust inhibitor, the catalyst and the anti-settling agent B to obtain the component B; the stirring speed is 1200r/min, and the stirring time is 15 min;

(4) and mixing and stirring the component A and the component B uniformly to obtain the solvent-free epoxy zinc-rich coating.

Comparative example 1

The product of the comparative example is a solvent-free zinc-rich coating prepared according to the formula of example 3 in the publication of CN 112500764A; the solvent-free zinc-rich coating comprises a component A and a component B, wherein the ratio of the component A to the component B is 0.95:1, and the component A comprises 5.6 parts of epoxy resin, 1.6 parts of reactive diluent, 0.5 part of thixotropic agent, 0.7 part of plasticizer, 0.3 part of dispersant, 0.3 part of coupling agent, 89 parts of 325-mesh zinc powder and 2 parts of glass flakes; the component B comprises 2.5 parts of modified phenolic amine curing agent, 2.5 parts of polyamide curing agent and 0.3 part of curing accelerator; the selection of specific components is as described in the section of the specific embodiment of CN 112500764A.

Comparative example 2

The comparative example differs from example 1 only in that the modified epoxy resin was replaced with a pure E51 type epoxy resin.

Comparative example 3

This comparative example differs from example 1 only in that the aqueous amine curing agent was replaced with NX-2003D curing agent manufactured by Kadeli corporation.

TABLE 1

Effect example 1

In order to verify the performance of each product in the examples of the present application, the products obtained in examples 1 to 5 and comparative examples 1 to 3 were subjected to property characterization and performance characterization, and the results are shown in table 2.

The nonvolatile content of the product is tested according to a GB/T1725 test method;

the drying time of the product is tested according to a GB/T1728 test method;

the content of Volatile Organic Compounds (VOCs) of the product is tested according to a GB/T23986 test method;

the neutral salt spray resistance of the product is tested according to a GB/T1771 method;

the adhesive force performance of the product is tested according to the GB/T1720 method;

the water resistance of the product is tested according to the HG/T5176 method;

the workability of the product was tested according to HG/T3668.

TABLE 2

As can be seen from Table 2, the lowest VOCs content of the solvent-free epoxy zinc-rich paint prepared in the embodiment of the application can be 10g/L, and the volatilization amount is very small; the surface drying time and the solid drying time can be effectively shortened under different high-humidity conditions, and the product has excellent salt spray resistance and water resistance, strong adhesive force, excellent workability and wide application field.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.