Ultra-long pot life solvent-free epoxy coating composition, coating, preparation method and application thereof

Abstract

The present invention discloses an ultra-long applicable period solvent-free epoxy coating composition, coating, preparation method and application thereof. The epoxy coating composition comprises a first component and a second component, wherein the first component comprises an epoxy resin, a pigment, a filler, an additive, a liquid petroleum resin and a difunctional glycidyl ether, and the second component comprises a GEI modified resin and a polyamide resin; the GEI modified resin is prepared by an addition reaction of 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether. The epoxy coating composition provided by the present invention has an ultra-long applicable period that is significantly better than that of commercially available products under an air temperature of 30°C, and is suitable for use in confined spaces such as the inner wall of a pipeline, the inner wall of a ship's oil tank, and other steel structure surfaces for corrosion and rust prevention. In addition, the product can make the construction site schedule more flexible, reduce the risks of paint agglutination and damage to spray equipment caused by the paint being left for too long, and the coating has excellent chemical resistance and salt spray resistance.

Description

Technical Field

[0001] The present invention relates to a coating material, in particular to an ultra-long-service-life solvent-free epoxy coating composition, a coating material, a preparation method and an application thereof, and belongs to the technical field of heavy-duty anti-corrosion coatings. Background Art

[0002] In enclosed or semi-enclosed spaces such as ship cabins and pipelines, due to poor air circulation, solvent-free epoxy coatings are often used to protect steel substrates. This ensures that the coating material can quickly crosslink to form a film, without the impact of solvent volatilization on coating performance. However, during use, solvent-free epoxy coatings react rapidly because there is no solvent barrier between the epoxy groups and the active hydrogen groups, resulting in close contact. This leads to a pot life of less than 1.5 hours, especially in the high temperatures of summer. At temperatures approaching 40°C, the paint can easily overheat, boil, and rapidly solidify within an hour, posing a significant challenge to construction site scheduling and also posing risks such as damage to spray equipment and burns to construction workers. To increase the pot life of solvent-free epoxy coatings, some coating manufacturers have attempted to address the problem by reducing crosslink density and adding high-boiling-point solvents. However, these methods can reduce the chemical resistance and corrosion resistance of the coating material. For these reasons, the industry urgently needs to develop a solvent-free epoxy coating with a longer application period and better overall performance to adapt to various complex construction environments and provide better anti-corrosion protection for the surfaces of steel structures such as ship cabins and pipelines. Summary of the Invention

[0003] The main purpose of the present invention is to provide a solvent-free epoxy coating composition with an ultra-long pot life, a coating and a preparation method thereof, so as to overcome the deficiencies in the prior art.

[0004] Another object of the present invention is to provide applications of the ultra-long-period solvent-free epoxy coating composition and coating.

[0005] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0006] An embodiment of the present invention provides an ultra-long pot life solvent-free epoxy coating composition, comprising: a first component and a second component, wherein the first component comprises an epoxy resin, a pigment, a filler, an additive, a liquid petroleum resin, and a difunctional glycidyl ether, and the second component comprises a GEI modified resin and a polyamide resin;

[0007] The GEI modified resin is prepared by an addition reaction between 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether.

[0008] In some embodiments, the first component includes the following components calculated in parts by weight: 40-50 parts of epoxy resin, 35-45 parts of pigments and fillers, 1-2 parts of additives, 3-7 parts of liquid petroleum resin, and 8-12 parts of difunctional glycidyl ether.

[0009] In some embodiments, the second component includes the following components calculated in parts by weight: 65-75 parts of GEI modified resin and 25-35 parts of polyamide resin.

[0010] The present invention also provides a method for preparing the aforementioned ultra-long pot life solvent-free epoxy coating composition, which comprises:

[0011] 2-phenylimidazoline is subjected to an addition reaction with glycerol tri(1,2-epoxy)propyl ether to prepare a GEI modified resin;

[0012] Evenly mixing epoxy resin, pigments and fillers, additives, liquid petroleum resin and difunctional glycidyl ether to obtain a first component;

[0013] uniformly mixing the GEI modified resin and the polyamide resin to obtain a second component;

[0014] The first component and the second component are mixed evenly to prepare the ultra-long pot life solvent-free epoxy coating composition.

[0015] In some embodiments, the preparation method comprises: adding glycerol tri(1,2-epoxy)propyl ether to 2-phenylimidazoline in batches under stirring until the equivalent ratio of 2-phenylimidazoline to glycerol tri(1,2-epoxy)propyl ether is 3.2-3.3:1, then heating to 55-65°C for addition reaction for 2-2.5 hours to obtain the GEI modified resin.

[0016] The embodiment of the present invention further provides an ultra-long pot life solvent-free epoxy coating, which is formed from the aforementioned ultra-long pot life solvent-free epoxy coating composition.

[0017] The embodiments of the present invention also provide the use of the aforementioned ultra-long pot life solvent-free epoxy coating composition or ultra-long pot life solvent-free epoxy coating in the field of steel substrate surface protection.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The ultra-long pot life solvent-free epoxy coating composition provided by the present invention, due to its use of specific raw material components, exhibits a significantly longer pot life than commercially available products at 30°C, and exhibits excellent coating performance. It is suitable for corrosion and rust prevention on confined spaces, such as the inner walls of pipelines and ship oil tanks, and other steel structures. Furthermore, this product's extended pot life allows for more flexible construction site scheduling, reducing the risks of paint agglomeration and damage to spray equipment caused by prolonged paint storage. The coating also exhibits excellent chemical and salt spray resistance, and the material is easy to prepare, making it suitable for large-scale production and application. DETAILED DESCRIPTION

[0020] In light of the aforementioned problems in the prior art, the inventors of the present invention, after extensive and in-depth research, have developed a novel solvent-free epoxy coating composition and coating material with an ultra-long pot life, significantly exceeding commercially available products and exhibiting superior film properties. The inventive concept of this invention is that the 2-phenylimidazoline structure is stable in the absence of water, but hydrolyzes upon contact with water, generating an amide group that then reacts with epoxy. Leveraging this principle, imidazoline can be formulated as a latent epoxy curing agent, thereby extending the pot life of solvent-free epoxy coatings.

[0021] Based on this, 2-phenylimidazoline can be reacted with trifunctional glycidyl ether to eliminate active hydrogen and transform it into a structure containing three imidazoline groups. The resultant can then be physically mixed with a common polyamide resin as a curing agent. In the curing agent, the active hydrogen content can be designed to be lower than the calculated value, that is, the active hydrogen content is very low. This effectively reduces the probability of collision between epoxy groups and active hydrogen in the packaging barrel before the paint is applied, thereby extending the pot life. After the paint is applied to the surface of the substrate, the paint film will come into contact with water vapor in the air, and the imidazoline will hydrolyze (the alkalinity of the amine will promote hydrolysis) to form an amide group, thereby replenishing the active hydrogen and allowing the epoxy group to react quickly to form a film.

[0022] The technical solution, its implementation process and principles are further explained below.

[0023] As one aspect of the technical solution of the present invention, an ultra-long application period solvent-free epoxy coating composition is provided, comprising: a first component and a second component, wherein the first component comprises epoxy resin, pigments, fillers, additives, liquid petroleum resin and difunctional glycidyl ether, and the second component comprises GEI modified resin and polyamide resin.

[0024] In some embodiments, the GEI modified resin is prepared by an addition reaction of 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether at an equivalent ratio of 3.2 to 3.3:1.

[0025] In some preferred embodiments, the 2-phenylimidazoline used in the preparation of the GEI modified resin has a weight average molecular weight of 140-150 and an active hydrogen equivalent of 140-150.

[0026] In some preferred embodiments, the weight average molecular weight of glycerol tri(1,2-epoxy)propyl ether used in the preparation of the GEI modified resin is 255-265, and the epoxy equivalent is 80-90.

[0027] In some more preferred embodiments, the GEI-modified resin is prepared by an addition reaction of 2-phenylimidazoline having a weight average molecular weight of 140-150 and an active hydrogen equivalent of 140-150 with glycerol tri(1,2-epoxy)propyl ether having a weight average molecular weight of 255-265 and an epoxy equivalent of 80-90 at an equivalent ratio of 3.2-3.3:1.

[0028] Furthermore, the GEI modified resin has a weight average molecular weight of 690-710 and an active hydrogen equivalent of 240-260.

[0029] In some embodiments, the first component includes the following components calculated in parts by weight: 40-50 parts of epoxy resin, 35-45 parts of pigments and fillers, 1-2 parts of additives, 3-7 parts of liquid petroleum resin, and 8-12 parts of difunctional glycidyl ether.

[0030] In some embodiments, the second component includes the following components calculated in parts by weight: 65-75 parts of GEI modified resin and 25-35 parts of polyamide resin.

[0031] In some more preferred embodiments, in the second component, the mass ratio of the GEI modified resin to the polyamide resin is 3:1.2-1.5.

[0032] In some embodiments, the mass ratio of the first component to the second component is 2.4-3.0:1.

[0033] In some embodiments, the epoxy resin includes bisphenol A epoxy resin with an epoxy equivalent weight of 180-190.

[0034] Furthermore, the pigments and fillers may include any one or more combinations of titanium dioxide, precipitated barium sulfate, talc, and silica powder, but are not limited thereto.

[0035] Furthermore, the auxiliary agent may include any one or more combinations of dispersants, defoamers, leveling agents, and rheological additives, but is not limited thereto.

[0036] In some embodiments, the liquid petroleum resin has a viscosity of 700 to 1300 cps and contains 5N9 carbon atoms in the molecule.

[0037] In some embodiments, the weight average molecular weight of the difunctional glycidyl ether is 225-235, and the molecule contains two epoxy groups.

[0038] Furthermore, the active hydrogen equivalent of the polyamide resin is 90-110.

[0039] As another aspect of the technical solution of the present invention, a method for preparing a solvent-free epoxy coating composition with an ultra-long pot life is provided, comprising:

[0040] 2-phenylimidazoline is subjected to an addition reaction with glycerol tri(1,2-epoxy)propyl ether to prepare a GEI modified resin;

[0041] Evenly mixing epoxy resin, pigments and fillers, additives, liquid petroleum resin and difunctional glycidyl ether to obtain a first component;

[0042] uniformly mixing the GEI modified resin and the polyamide resin to obtain a second component;

[0043] The first component and the second component are mixed evenly to prepare the ultra-long pot life solvent-free epoxy coating composition.

[0044] In some specific embodiments, the preparation process of the GEI-modified resin includes: adding glycerol tri(1,2-epoxy)propyl ether to 2-phenylimidazoline in batches under stirring conditions until the equivalent ratio of 2-phenylimidazoline to glycerol tri(1,2-epoxy)propyl ether is 3.2-3.3:1 (i.e., a mass ratio of 5.4-5.6:1) and 2-phenylimidazoline is in excess, then heating to 55-65° C. for addition reaction for 2-2.5 hours, and the product is glycerol ether-triphenylimidazoline, referred to as GEI-modified resin.

[0045] The present invention uses 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether containing three epoxy groups to undergo an addition reaction, eliminating the active hydrogen of the 2-phenylimidazoline. The resulting GEI-modified resin structure contains three imidazoline groups. Imidazolinone is stable in the absence of water. Furthermore, the imidazoline in the GEI-modified resin structure contains only tertiary amines. While this promotes the ring opening of the epoxy groups, the lack of active hydrogen results in a very slow reaction rate for epoxy ring-opening polymerization. Therefore, after mixing the GEI-modified resin with the epoxy resin, it can maintain a stable state for a long time in a hydrophobic environment without reacting.

[0046] When the coating composition is applied to a substrate, it comes into contact with air, and the polyamide resin migrates to the coating surface. While reacting with the epoxy groups, its hydrophilic nature makes the coating more susceptible to moisture in the air, promoting the ring-opening of the imidazoline group to form an amidoamine, which then reacts with the epoxy groups to crosslink. During this process, the tertiary amine in the GEI structure also promotes the ring-opening reaction of the epoxy group, improving the drying properties of the coating film.

[0047] Since the GEI modified resin structure contains three imidazoline groups, the structure after hydrolysis has three amino groups. After cross-linking with the bifunctional bisphenol A epoxy resin, it can form a three-dimensional network coating structure, thereby improving the paint film strength, hydrophobicity and coating resistance.

[0048] Furthermore, the GEI-modified resin acts as a latent curing agent, not reacting directly with the first component, thus ensuring an exceptionally long pot life. Furthermore, when the GEI-modified resin is mixed with the first component and applied to a substrate, its increased surface area allows it to react with moisture in the air to form a polyamide, which then reacts with the epoxy resin in the first component, forming a cross-linked film.

[0049] In some preferred embodiments, the 2-phenylimidazoline used in the preparation of the GEI modified resin has a weight average molecular weight of 140-150 and an active hydrogen equivalent of 140-150.

[0050] In some preferred embodiments, the weight average molecular weight of glycerol tri(1,2-epoxy)propyl ether used in the preparation of the GEI modified resin is 255-265, and the epoxy equivalent is 80-90.

[0051] In one embodiment, the preparation method further comprises: uniformly mixing the first component and the second component in a mass ratio of 2.4 to 3.0:1.

[0052] Among them, as one of more specific embodiments, the preparation method of the ultra-long pot life solvent-free epoxy coating composition may include the following steps:

[0053] 2-phenylimidazoline was added to a reaction kettle, and glycerol tri(1,2-epoxy)propyl ether was added in batches under low-speed stirring until the equivalent ratio of 2-phenylimidazoline to glycerol tri(1,2-epoxy)propyl ether was 3.2-3.3:1. The temperature was then raised to 55-65° C., and the addition reaction was carried out under stirring for 2-2.5 hours. The mixture was cooled to room temperature to obtain a GEI modified resin.

[0054] The GEI modified resin and the polyamide resin are uniformly mixed to obtain a second component;

[0055] The epoxy resin, pigments and fillers, additives, liquid petroleum resin and difunctional glycidyl ether are mixed uniformly to obtain a first component.

[0056] The first component and the second component are uniformly mixed in a mass ratio of 2.4 to 3.0:1 to obtain the ultra-long pot life solvent-free epoxy coating material.

[0057] For example, 2-phenylimidazoline can be added to a reactor, and the stirrer is turned on and stirred at a speed of 300 to 500 r / min. Then, under stirring conditions, glycerol tri(1,2-epoxy)propyl ether is slowly added to 2-phenylimidazoline according to an equivalent ratio of 2-phenylimidazoline to glycerol tri(1,2-epoxy)propyl ether of 3.2 to 3.3:1. The mixture is stirred continuously and the temperature is controlled at 55 to 65° C. for 2 to 2.5 hours. After cooling to room temperature, the GEI modified resin is obtained.

[0058] In one embodiment, the preparation method specifically comprises: uniformly mixing the GEI modified resin and the polyamide resin under low-speed stirring conditions of 300 to 500 r / min to obtain the second component.

[0059] In one embodiment, the preparation method specifically includes: mixing the epoxy resin with the pigment, filler, additive, difunctional glycidyl ether and liquid petroleum resin in sequence, and then dispersing it at a speed of 2000-3000 r / min for 25-30 minutes, and then adjusting the viscosity of the obtained mixture to 120-130 KU with another portion of difunctional glycidyl ether to obtain the first component.

[0060] Another aspect of the embodiments of the present invention further provides an ultra-long pot life solvent-free epoxy coating, which is formed from the aforementioned ultra-long pot life solvent-free epoxy coating composition.

[0061] Furthermore, the thickness of the ultra-long pot life solvent-free epoxy coating is 300 to 320 μm.

[0062] Another aspect of the embodiments of the present invention further provides the application of the aforementioned ultra-long-term solvent-free epoxy coating composition or ultra-long-term solvent-free epoxy coating in the field of steel substrate surface protection in closed environments such as ship cabins or pipeline inner walls.

[0063] Furthermore, the application includes: applying the aforementioned ultra-long pot life solvent-free epoxy coating composition to the surface of a steel substrate to form a protective coating.

[0064] For example, one embodiment of the present invention provides an application method of an ultra-long pot life solvent-free epoxy coating composition, which comprises: forming the ultra-long pot life solvent-free epoxy coating composition, which has an ultra-long pot life of not less than 6 hours at 30°C, and can effectively reduce the risks of paint agglomeration and damage to spraying equipment caused by the paint being placed for too long.

[0065] In summary, the GEI-modified resin provided by the present invention can act as a latent curing agent for epoxy groups within epoxy resins. Therefore, when designing solvent-free epoxy coatings, the active hydrogen content in the mixed system can be reduced by combining polyamide resin with the GEI-modified resin, thereby effectively reducing the probability of collision between epoxy groups and active hydrogen, extending the pot life, and ensuring rapid crosslinking after coating, without affecting the ultimate performance of the coating.

[0066] For example, after the first and second components of the coating composition are fully mixed, the coating temperature can be maintained at no more than 50°C after 6 hours at 30°C, and the coating exhibits fluidity. After the coating film is fully cured, it undergoes immersion in a 10% sulfuric acid solution for 30 days without blistering, peeling, or rusting. The film also withstands neutral salt spray for 3,000 hours without blistering, peeling, or rusting, and exhibits adhesion after salt spray of no less than 8MPa. This product has an exceptionally long pot life, allowing for more flexible construction site scheduling and reducing the risks of paint agglomeration and damage to spray equipment caused by prolonged paint storage. Furthermore, the coating exhibits excellent chemical and salt spray resistance, and the material is easy to prepare, making it suitable for large-scale production and application.

[0067] The technical solutions of the present invention are further illustrated below with reference to several examples, but the invention is not limited to the scope of the examples. The reagents and raw materials used in the following examples are all commercially available. Test methods where specific conditions are not specified are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers. In addition, in the following examples, low-speed stirring refers to a rotational speed of 500 r / min or less, 500-2000 r / min refers to medium-speed stirring, and high-speed stirring refers to a rotational speed of 2000 r / min or more. High-speed dispersion refers to a rotational speed of 2000-3000 r / min.

[0068] Example 1

[0069] A method for preparing a coating composition for forming a solvent-free epoxy coating material with an ultra-long pot life comprises the following steps:

[0070] (1) Add 5400 g of 2-phenylimidazoline to the reactor, start the stirrer and stir at a speed of 300 r / min, then slowly add 1000 g of glycerol tri(1,2-epoxy)propyl ether to the 2-phenylimidazoline under stirring conditions, continue stirring and control the temperature at 65°C for 2 h, and cool to room temperature to obtain GEI modified resin.

[0071] (2) Add 3000 g of GEI modified resin and 1200 g of polyamide resin into a reaction kettle, stir and disperse at medium speed for 10 minutes to obtain the second component.

[0072] (3) 4300 g of epoxy resin was mixed with 2500 g of titanium dioxide, 1500 g of precipitated barium sulfate, 100 g of dispersant, 100 g of rheological additive, 850 g of difunctional glycidyl ether and 500 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. Then, the viscosity of the mixture was adjusted to about 120 KU with 150 g of difunctional glycidyl ether to obtain the first component.

[0073] (4) The first component and the second component are uniformly mixed in a mass ratio of about 2.4:1 to obtain a coating composition for forming a solvent-free epoxy coating material with an ultra-long application period.

[0074] Example 2

[0075] A method for preparing a coating composition for forming a solvent-free epoxy coating material with an ultra-long pot life comprises the following steps:

[0076] (1) Add 5600 g of 2-phenylimidazoline to the reactor, start the stirrer and stir at a speed of 500 r / min, then slowly add 1000 g of glycerol tri(1,2-epoxy)propyl ether to the 2-phenylimidazoline under stirring conditions, continue stirring and control the temperature at 55°C for 2.5 h, and cool to room temperature to obtain GEI modified resin.

[0077] (2) Add 3000 g of GEI modified resin and 1500 g of polyamide resin into a reactor, stir and disperse at medium speed for 10 minutes to obtain the second component.

[0078] (3) 4300 g of epoxy resin was mixed with 2500 g of titanium dioxide, 1500 g of precipitated barium sulfate, 100 g of dispersant, 100 g of rheological additive, 850 g of difunctional glycidyl ether and 500 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. Then, the viscosity of the mixture was adjusted to about 120 KU with 150 g of difunctional glycidyl ether to obtain the first component.

[0079] (4) The first component and the second component are uniformly mixed in a mass ratio of about 3:1 to obtain a coating composition for forming a solvent-free epoxy coating material with an ultra-long application period.

[0080] Example 3

[0081] A method for preparing a coating composition for forming a solvent-free epoxy coating material with an ultra-long pot life comprises the following steps:

[0082] (1) Add 5500 g of 2-phenylimidazoline to the reactor, start the stirrer and stir at a speed of 300 r / min, then slowly add 1000 g of glycerol tri(1,2-epoxy)propyl ether to the 2-phenylimidazoline under stirring conditions, continue stirring and control the temperature at 60°C for 2 h, and cool to room temperature to obtain GEI modified resin.

[0083] (2) Add 3000 g of GEI modified resin and 1350 g of polyamide resin into a reactor, stir and disperse at medium speed for 10 minutes to obtain the second component.

[0084] (3) 4800 g of epoxy resin was mixed with 2100 g of titanium dioxide, 1400 g of precipitated barium sulfate, 100 g of dispersant, 100 g of rheological additive, 850 g of difunctional glycidyl ether and 500 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. The viscosity of the mixture was then adjusted to about 120 KU with 150 g of difunctional glycidyl ether to obtain the first component.

[0085] (4) The first component and the second component are uniformly mixed in a mass ratio of about 2.7:1 to obtain a coating composition for forming a solvent-free epoxy coating material with an ultra-long application period.

[0086] Example 4

[0087] A method for preparing a coating composition for forming a solvent-free epoxy coating material with an ultra-long pot life comprises the following steps:

[0088] (1) Add 5400 g of 2-phenylimidazoline to the reactor, start the stirrer and stir at a speed of 400 r / min, then slowly add 1000 g of glycerol tri(1,2-epoxy)propyl ether to the 2-phenylimidazoline under stirring conditions, continue stirring and control the temperature at 65°C for 2 h, and cool to room temperature to obtain GEI modified resin.

[0089] (2) Add 3000 g of GEI modified resin and 1200 g of polyamide resin into a reaction kettle, stir and disperse at medium speed for 10 minutes to obtain the second component.

[0090] (3) 4300 g of epoxy resin was mixed with 2200 g of titanium dioxide, 300 g of precipitated barium sulfate, 800 g of talc, 700 g of silica powder, 100 g of dispersant, 100 g of rheological additive, 850 g of difunctional glycidyl ether and 500 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. Thereafter, the viscosity of the mixture was adjusted to about 120 KU with 150 g of difunctional glycidyl ether to obtain the first component.

[0091] (4) The first component and the second component are uniformly mixed in a mass ratio of about 2.4:1 to obtain a coating composition for forming a solvent-free epoxy coating material with an ultra-long application period.

[0092] Example 5

[0093] Compared with Example 1, this embodiment differs in that:

[0094] (3) 4000 g of epoxy resin was mixed with 2500 g of titanium dioxide, 2000 g of precipitated barium sulfate, 100 g of rheological additive, 100 g of defoamer, 650 g of difunctional glycidyl ether and 300 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. The viscosity of the mixture was then adjusted to about 120 KU with 350 g of difunctional glycidyl ether to obtain the first component.

[0095] Example 6

[0096] Compared with Example 1, this embodiment differs in that:

[0097] (3) 5000 g of epoxy resin was mixed with 1500 g of titanium dioxide, 1500 g of precipitated barium sulfate, 200 g of talc, 200 g of silica powder, 100 g of rheological additive, 650 g of difunctional glycidyl ether and 700 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. The viscosity of the mixture was then adjusted to about 120 KU with 150 g of difunctional glycidyl ether to obtain the first component.

[0098] Example 7

[0099] Compared with Example 1, this embodiment differs in that:

[0100] (3) 4000 g of epoxy resin was mixed with 2500 g of titanium dioxide, 1500 g of precipitated barium sulfate, 200 g of talc, 300 g of silica powder, 100 g of rheological additive, 850 g of difunctional glycidyl ether and 300 g of liquid petroleum resin in sequence, and dispersed at high speed for about 30 min. The viscosity of the mixture was then adjusted to about 120 KU with 250 g of difunctional glycidyl ether to obtain the first component.

[0101] Comparative Example 1

[0102] The preparation method of a coating composition provided in this comparative example is basically the same as that of Example 1, except that the GEI modified resin in Example 1 is replaced by unmodified 2-phenylimidazoline.

[0103] Comparative Example 2

[0104] The preparation method of a coating composition provided in this comparative example is basically the same as that of Example 1, except that the reaction equivalent ratio of 2-phenylimidazoline to glycidyl ether in Example 1 is changed to 2:1.

[0105] Comparative Example 3

[0106] The preparation method of a coating composition provided in this comparative example is basically the same as that of Example 1, except that the weight ratio of the GEI modified resin to the polyamide resin in Example 1 is changed to 4:1.

[0107] Comparative Example 4

[0108] The preparation method of a coating composition provided in this comparative example is basically the same as that of Example 1, with the only difference being that the mass ratio of the first component to the second component in Example 1 is changed to 4:1.

[0109] Comparative Example 5

[0110] The preparation method for the coating composition provided in this comparative example is essentially the same as that in Example 1, except that the GEI-modified resin in the second component of Example 1 is replaced with a polyamide resin. This shortens the pot life to less than 40 minutes, with the paint rapidly heating to boiling within 40-45 minutes.

[0111] Comparative Example 6

[0112] The preparation method for a coating composition provided in this comparative example is essentially the same as that of Example 1, except that the addition of 2-phenylimidazoline to the GEI-modified resin, the second component, in Example 1, is omitted. Without the addition of imidazoline, glycerol tri(1,2-epoxy)propyl ether would further consume some of the polyamide in the second component, resulting in insufficient active hydrogen content. Consequently, when the first and second components are mixed, they cannot dry to form a film.

[0113] The first component and the second component of the coating compositions of Examples 1-7 and Comparative Examples 1-6 and a commercially available conventional solvent-free epoxy coating were uniformly mixed, the pot life was tested, and then the coatings were applied to sandblasted steel plates to form coatings of equal thickness. The properties of these coatings were tested, and the corresponding test results are shown in Table 1. The test results in Table 1 are the average values ​​of the test results of multiple batches of products.

[0114] Table 1 Performance test results of coating compositions of Examples 1-7 and Comparative Examples 1-6 and commercially available conventional solvent-free epoxy coatings after forming coatings

[0115]

[0116] As shown in Table 1, the coating compositions of Examples 1-7 can be used to form solvent-free epoxy coating materials with an extremely long pot life. After thorough mixing of the first and second components of the coating, the coating temperature can be maintained at or below 50°C at 30°C for 6 hours, and the coating exhibits fluidity. After complete curing, the coating film exhibits no blistering, peeling, or rusting after immersion in a 10% sulfuric acid solution for 30 days. The film also exhibits no blistering, peeling, or rusting after 3000 hours of neutral salt spray resistance, and exhibits an adhesion of no less than 8 MPa after salt spray. This product's extremely long pot life allows for more flexible construction site scheduling and reduces the risks of paint agglomeration and damage to spray equipment caused by prolonged paint storage. Furthermore, the coating film exhibits excellent chemical and salt spray resistance, with overall performance far exceeding that of conventional commercially available solvent-free epoxy coatings.

[0117] In addition, the inventors of this case also conducted experiments with other raw materials and conditions listed in this specification, referring to the aforementioned embodiments, and obtained similar results.

[0118] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A solvent-free epoxy coating composition with an ultra-long pot life, characterized in that: include: A first component and a second component, wherein the first component comprises the following components calculated in parts by weight: 40-50 parts of epoxy resin, 35-45 parts of pigments and fillers, 1-2 parts of additives, 3-7 parts of liquid petroleum resin, and 8-12 parts of difunctional glycidyl ether; and the second component comprises the following components calculated in parts by weight: 65-75 parts of GEI modified resin and 25-35 parts of polyamide resin; the mass ratio of the first component to the second component is 2.4-3.0:1; The GEI modified resin is prepared by an addition reaction between 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether.

2. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The GEI modified resin is prepared by an addition reaction of 2-phenylimidazoline and glycerol tri(1,2-epoxy)propyl ether at an equivalent ratio of 3.2-3.3:

1.

3. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The weight average molecular weight of the 2-phenylimidazoline is 140-150, and the active hydrogen equivalent is 140-150.

4. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The weight average molecular weight of the glycerol tri(1,2-epoxy)propyl ether is 255-265, and the epoxy equivalent is 80-90.

5. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The GEI modified resin has a weight average molecular weight of 690-710 and an active hydrogen equivalent of 240-260.

6. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The epoxy resin includes bisphenol A epoxy resin with an epoxy equivalent of 180-190.

7. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The pigments and fillers include any one or more combinations of titanium dioxide, precipitated barium sulfate, talc and silica powder.

8. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The auxiliary agent includes any one or more combinations of dispersants, defoamers, leveling agents and rheological additives.

9. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The viscosity of the liquid petroleum resin is 700-1300 cps, and the molecules contain 5-9 carbon atoms.

10. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The weight average molecular weight of the difunctional glycidyl ether is 225-235, and the molecule contains two epoxy groups.

11. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: The active hydrogen equivalent of the polyamide resin is 90-110.

12. The ultra-long pot life solvent-free epoxy coating composition according to claim 1, characterized in that: In the second component, the mass ratio of GEI modified resin to polyamide resin is 3:1.2-1.

5.

13. The method for preparing the ultra-long pot life solvent-free epoxy coating composition according to any one of claims 1 to 12, characterized in that: include: 2-phenylimidazoline is subjected to an addition reaction with glycerol tri(1,2-epoxy)propyl ether to prepare a GEI modified resin; Evenly mixing epoxy resin, pigments and fillers, additives, liquid petroleum resin and difunctional glycidyl ether to obtain a first component; uniformly mixing the GEI modified resin and the polyamide resin to obtain a second component; The first component and the second component are mixed evenly to prepare the ultra-long pot life solvent-free epoxy coating composition.

14. The preparation method according to claim 13, characterized in that include: Under stirring conditions, glycerol tri(1,2-epoxy)propyl ether was added batchwise to 2-phenylimidazoline until the equivalent ratio of 2-phenylimidazoline to glycerol tri(1,2-epoxy)propyl ether was 3.2-3.3:1, and then the temperature was raised to 55-65° C. for addition reaction for 2-2.5 hours to obtain the GEI modified resin.

15. The preparation method according to claim 13, characterized in that include: The first component and the second component are uniformly mixed in a mass ratio of 2.4 to 3.0:1 to prepare the ultra-long pot life solvent-free epoxy coating composition.

16. A solvent-free epoxy coating with an ultra-long pot life, characterized in that: The ultra-long pot life solvent-free epoxy coating is formed from the ultra-long pot life solvent-free epoxy coating composition according to any one of claims 1 to 12.

17. The ultra-long pot life solvent-free epoxy coating according to claim 16, characterized in that: The thickness of the ultra-long pot life solvent-free epoxy coating is 300-320 μm.

18. Use of the ultra-long pot life solvent-free epoxy coating composition according to any one of claims 1 to 12 or the ultra-long pot life solvent-free epoxy coating according to claim 16 in the field of surface protection of steel substrates.

19. The use according to claim 18, characterized in that include: The ultra-long pot life solvent-free epoxy coating composition according to any one of claims 1 to 12 is applied to the surface of a steel substrate to form a protective coating.

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