Universal metal baking varnish

Abstract

The invention is suitable for the technical field of coatings, and particularly relates to a general metal baking varnish which comprises 30-40 parts of polyester resin, 20-30 parts of an epoxy resin solution, 25-35 parts of amino resin, 0.5-5 parts of phosphate, 3-20 parts of a solvent and 0.1-1 part of a flatting agent. According to the general metal stoving varnish provided by the invention, the epoxy resin is excessively used and becomes the second main body resin, so that the crosslinking degree and the adhesive force are improved, the chemical resistance of the epoxy resin is fully reflected in the technical scheme, and the metal stoving varnish prepared by the technical scheme is suitable for all metal products seen in the market; the melamine formaldehyde resin mixed and etherified by methanol and butanol is used, so that the toughness and tensile strength are improved, the crosslinking density is improved, a more compact crosslinking network is formed, and the adhesive force and other properties of the metal baking varnish to various metals are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a universal metal baking varnish. Background Art

[0002] Metal paint has a history of more than 60 years in my country. Most of the metal products we see in production and life are made of iron, aluminum, copper, carbon steel, nickel-plated plate, galvanized plate, stainless steel, aluminum alloy, zinc alloy, magnesium alloy and other materials. After these metal objects are manufactured, they need to be sprayed with a layer of metal paint on their surface to increase the durability, aesthetics, stone resistance, chemical resistance (salt spray resistance, acid and alkali resistance, engine oil resistance) and other properties of the objects. The conventional metal paint varieties currently available in China include alkyd / amino paint, acrylic / amino paint, polyester / amino paint, etc. However, these types of paints have the problem of lack of commonality in adhesion and narrow application range, and it is difficult to achieve good adhesion to all the above-mentioned types of metal products. For example: alkyd / amino paint has good adhesion only to iron products, and has poor adhesion to other metal products, so this type of paint is only suitable for iron products. Acrylic / amino paint and polyester / amino paint are suitable for iron products, aluminum products, stainless steel products, and carbon steel products, but not for copper products, zinc products, and alloy products. The adhesion to these products is very poor, and the paint film is easy to fall off. Adhesion is the most basic and most important performance of metal paint. In the case of unqualified adhesion, all other properties (such as hardness, toughness, impact resistance, wear resistance, oil resistance, acid and alkali resistance, salt spray resistance, etc.) are out of the question and cannot be tested. Therefore, the adhesion of metal paint is the soul of metal paint and the gold standard for whether metal paint is necessary. Once the adhesion is lost, the paint film falls off, causing the metal to be exposed, losing its decorative and protective functions, and the metal paint loses its meaning of existence.

[0003] The reason why the adhesion of the above-mentioned metal paints (alkyd / amino paint, acrylic / amino paint, polyester / amino paint, etc.) lacks versatility and has a narrow application range is that, firstly, the types of groups participating in the reaction of the main resin are not rich enough, mainly hydroxyl and carboxyl groups, resulting in poor adhesion to metals with low surface energy. Secondly, the etherifying agent of amino resin is generally butanol or methanol, and the synthesized amino resins are butyl etherified amino resin and methyl etherified amino resin. Both of these amino resins have their own advantages and disadvantages, and it is impossible to achieve balanced and comprehensive performance.

[0004] Since metal paint has not been able to overcome the problems of poor adhesion and narrow application range, metal product spraying companies have to purchase multiple metal paints at the same time to meet the requirements of different metal products. They even spend a lot of money to ask paint manufacturers to customize special paints for certain metal products, but even so, they have not been able to solve the problem of adhesion and universality of metal paints. Summary of the invention

[0005] The purpose of the present invention is to provide a universal metal paint, aiming to solve the problem that metal paint has not been able to break through the poor adhesion and versatility and narrow application range, resulting in metal product spraying companies having to purchase multiple metal paints at the same time when purchasing metal paints and facing the requirements of different metal products.

[0006] The present invention is achieved by providing a universal metal baking paint, which comprises 30-40 parts of polyester resin, 20-30 parts of epoxy resin solution, 25-35 parts of amino resin, 0.5-5 parts of phosphate ester, 3-20 parts of solvent and 0.1-1 part of leveling agent.

[0007] Preferably, the polyester resin is a thermosetting polyester resin.

[0008] Preferably, the epoxy resin solution is a solution obtained by dissolving a solid epoxy resin in a solvent, wherein the solid epoxy resin is a bisphenol A epoxy resin.

[0009] Preferably, the amino resin is a melamine formaldehyde resin, and the melamine formaldehyde resin is a melamine formaldehyde resin obtained by mixing butanol and methanol for etherification.

[0010] Preferably, the phosphate ester is a composite of polyester and phosphoric acid.

[0011] Preferably, the leveling agent is a silicon-containing leveling agent, and the silicon-containing leveling agent is a polyester-modified organic silicon leveling agent.

[0012] Preferably, the solvent is an alcohol solvent or an ester solvent.

[0013] Preferably, the epoxy resin content in the epoxy resin solution is 70%.

[0014] The universal metal baking varnish provided by the present invention uses an excess amount of epoxy resin, making it the second main resin, thereby improving the crosslinking degree and adhesion, allowing the chemical resistance of the epoxy resin to be fully reflected in the technical solution, so that the metal baking varnish prepared by the technical solution is suitable for all metal products seen on the market; melamine formaldehyde resin mixed with methanol and butanol is used to improve the toughness and tensile strength, increase the crosslinking density, form a denser crosslinking network, and improve the adhesion and other properties of the metal baking varnish to various metals. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] In one embodiment of the present invention, a universal metal baking paint is provided, which includes 30-40 parts of polyester resin, 20-30 parts of epoxy resin solution, 25-35 parts of amino resin, 0.5-5 parts of phosphate ester, 3-20 parts of solvent and 0.1-1 part of leveling agent.

[0017] In this embodiment, a general metal baking paint is prepared from the following components: polyester resin, epoxy resin solution, amino resin, phosphate ester, solvent and leveling agent; the polyester resin is a thermosetting polyester resin; the epoxy resin solution is a solution obtained by dissolving solid epoxy resin and solvent; the amino resin is melamine formaldehyde resin; the phosphate ester is a composite of polyester and phosphoric acid; the solvent is a solvent free of benzene or benzene derivatives; the leveling agent is a silicon-containing leveling agent; the thermosetting polyester resin has a solid content of 70%; the solid epoxy resin is a bisphenol A type epoxy resin; the melamine formaldehyde resin is a melamine formaldehyde resin mixed with butanol and methanol etherification; the acid value of the composite is greater than 30 mgKOH / g; the solvent is an alcohol solvent or an ester solvent; the silicon-containing leveling agent is a polyester-modified silicone leveling agent; the epoxy resin solution has an epoxy resin content of 70%; the melamine formaldehyde resin has a solid content of greater than 80%.

[0018] The mass percentages of the various components are as follows: polyester resin: 30-40 parts; epoxy resin solution: 20-30 parts; amino resin: 25-35 parts; phosphate ester: 0.5-5 parts; solvent: 3-20 parts; and leveling agent: 0.1-1 parts.

[0019] The optimized percentages are as follows: polyester resin: 33-36 parts; epoxy resin solution: 23-26 parts; amino resin: 28-31 parts; phosphate ester: 1-4 parts; solvent: 5-15 parts; leveling agent: 0.2-0.6 parts.

[0020] Each component must be weighed accurately and stirred in the stirring tank for at least 30 minutes at a minimum stirring speed of 400r / m.

[0021] Due to the excessive use of epoxy resin, the reactive groups include a large number of epoxy groups in addition to hydroxyl and carboxyl groups. At a certain temperature, the hydroxyl, carboxyl, epoxy groups and the imino and alkoxy groups of the amino resin simultaneously produce cross-linking reactions to form a dense and hard cross-linking network. Under the action of phosphate esters, a phosphating effect is further produced and an anchoring group is formed. The amino resin uses a melamine formaldehyde resin mixed with methanol and butanol etherification, which provides extremely high toughness and tensile strength.

[0022] Under the influence of the above factors, the metal paint obtained by the present invention has a wide range of universal adhesion, and has excellent adhesion to various metal products such as iron, aluminum, copper, carbon steel, nickel-plated plate, galvanized plate, stainless steel, aluminum alloy, zinc alloy, magnesium alloy, etc., and has good hardness and good toughness. It completely solves the problems of poor universal adhesion and narrow application range of conventional alkyd / amino paint, acrylic / amino paint, polyester / amino paint, etc.

[0023] The present invention has completely broken through the conventional main resin + cross-linking resin metal paint technology framework, forming a two-main resin + one cross-linking resin metal paint technology framework, namely, polyester / epoxy / amino framework.

[0024] This structure, in addition to achieving wide adhesion, also greatly improves the hardness, stone impact resistance, salt spray resistance, acid and alkali resistance, and gasoline resistance of the paint film, bringing the overall quality of metal paint to a higher level.

[0025] Embodiment 1,

[0026] Formula: polyester resin: 33 parts; epoxy resin solution: 23 parts; amino resin: 28 parts; phosphate ester: 3 parts; solvent: 12.7 parts; leveling agent: 0.3 parts.

[0027] Implementation method: weigh the above materials accurately and set aside. First, put the polyester resin into the stirring kettle, start the motor, adjust the speed to 600 rpm, and add the epoxy resin solution, amino resin, phosphate ester, solvent, and leveling agent in sequence. Continue stirring for 30 minutes. Let it stand and defoam for 30 minutes. Filter and package to obtain the universal metal baking paint described in this technical solution.

[0028] Embodiment 2:

[0029] Formula: polyester resin: 36 parts; epoxy resin solution: 26 parts; amino resin: 31 parts; phosphate ester: 1 part; solvent: 5.7 parts; leveling agent: 0.3 parts.

[0030] Implementation method: weigh the above materials accurately and set aside. First, put the polyester resin into the stirring kettle, start the motor, adjust the speed to 1000 rpm, and add the epoxy resin solution, amino resin, phosphate ester, solvent, and leveling agent in sequence. Continue stirring for 30 minutes. Let it stand and defoam for 30 minutes. Filter and package to obtain the universal metal baking paint described in this technical solution.

[0031] Embodiment 3,

[0032] Formula: polyester resin: 34.5 parts; epoxy resin solution: 24.5 parts; amino resin: 29.5 parts; phosphate ester: 2 parts; solvent: 9.2 parts; leveling agent: 0.3 parts.

[0033] Implementation method: weigh the above materials accurately and set aside. First, put the polyester resin into the stirring kettle, start the motor, adjust the speed to 800 rpm, and add the epoxy resin solution, amino resin, phosphate ester, solvent, and leveling agent in sequence. Continue stirring for 30 minutes. Let it stand and defoam for 30 minutes. Filter and package to obtain the universal metal baking paint described in this technical solution.

[0034] Embodiment 4:

[0035] Formula: polyester resin: 33 parts; epoxy resin solution: 26 parts; amino resin: 29.5 parts; phosphate ester: 2 parts; solvent: 9.2 parts; leveling agent: 0.3 parts.

[0036] Implementation method: weigh the above materials accurately and set aside. First, put the polyester resin into the stirring kettle, start the motor, adjust the speed to 800 rpm, and add the epoxy resin solution, amino resin, phosphate ester, solvent, and leveling agent in sequence. Continue stirring for 30 minutes. Let it stand and defoam for 30 minutes. Filter and package to obtain the universal metal baking paint described in this technical solution.

[0037] Embodiment 5,

[0038] Formula: polyester resin: 36 parts; epoxy resin solution: 23 parts; amino resin: 29.5 parts; phosphate ester: 2 parts; solvent: 9.2 parts; leveling agent: 0.3 parts.

[0039] Implementation method: weigh the above materials accurately and set aside. First, put the polyester resin into the stirring kettle, start the motor, adjust the speed to 800 rpm, and add the epoxy resin solution, amino resin, phosphate ester, solvent, and leveling agent in sequence. Continue stirring for 30 minutes. Let it stand and defoam for 30 minutes. Filter and package to obtain the universal metal baking paint described in this technical solution.

[0040] Performance evaluation:

[0041] The above embodiments were compared with commercially available alkyd / amino metal paint, acrylic / amino metal paint, and polyester / amino metal paint for performance evaluation.

[0042] The most basic and most important performance that needs to be compared and evaluated for metal paint is adhesion.

[0043] Other properties that need to be compared and evaluated for metal baking paint are: hardness, impact resistance, salt spray resistance, engine oil resistance, acid resistance and alkali resistance.

[0044] Preparation of samples required for comparative evaluation: The metal paint of each embodiment and the commercially available alkyd / amino metal paint, acrylic / amino metal paint, and polyester / amino metal paint are coated on standard metal samples of certain specifications using a wet film applicator, and after baking at a constant temperature of 150 degrees for 30 minutes, they are taken out, cooled for 2 hours, and tested. The materials of the standard metal samples are: tinplate, aluminum plate, copper plate, carbon steel plate, nickel-plated plate, galvanized plate, stainless steel plate, aluminum alloy plate, zinc alloy plate, magnesium alloy plate, etc.

[0045] The comparative evaluation of adhesion of various types of commercially available metal paints and the metal paints in the examples is shown in the following table:

[0046]

[0047] Note: A. The adhesion test method is the grid knife-adhesive tape method.

[0048] B. The evaluation standard for adhesion is GB / T9286-1998.

[0049] C, the adhesion is judged on a scale of 0-5: 0 is excellent; 1 is good; 2 is fair; 3 is poor; 4 is bad; 5 is the worst.

[0050] D. The "no adhesion" described in the table is a state where the coating film falls off in large areas.

[0051] The hardness comparison and evaluation of various types of commercially available metal paints and the metal paints in the examples are shown in the following table:

[0052]

[0053] Note: A. Hardness test method: 1 kg pencil pusher method.

[0054] B, the hardness is judged as follows: 6B-6H Chinese pencil standard.

[0055] C, the hardness rating is: 6B is the lowest and -6H is the highest.

[0056] D. The sample for hardness test is tinplate.

[0057] The impact resistance of various commercially available metal paints and the metal paints in the examples is compared and evaluated as shown in the following table:

[0058]

[0059] Note: A. The impact resistance test method is: GB / T1732-2020. (recoil method: paint film facing down).

[0060] B. The criteria for impact resistance test is that the paint film at the impacted part does not crack or fall off.

[0061] C, the evaluation level of impact resistance test is: 50CM is the highest.

[0062] D. The sample for impact resistance test is tinplate.

[0063] The salt spray resistance of various commercially available metal paints and the metal paints in the examples is compared and evaluated as shown in the following table:

[0064]

[0065] Note: A. The test method for salt spray resistance is: salt spray chamber test. The salt water is 5% sodium chloride solution.

[0066] B. The "salt spray resistance time" described in this table is the time required for the first bubble to appear on the paint film of the sample in a salt spray environment.

[0067] C. The evaluation method of salt spray resistance is: the shorter the salt spray resistance time, the worse the performance. The longer the salt spray resistance time, the better the performance.

[0068] D. The sample for salt spray resistance test is tinplate.

[0069] The comparison and evaluation of the oil resistance of various types of commercially available metal paints and the metal paints in the examples are shown in the following table:

[0070]

[0071] Note: A. The test method for engine oil resistance is: immerse the sample in engine oil.

[0072] B. The "engine oil resistance time" described in this table is the time required for the first bubble to appear on the paint film of the sample in the engine oil.

[0073] C. The evaluation method of engine oil resistance is: the shorter the engine oil resistance time, the worse the performance. The longer the engine oil resistance time, the better the performance.

[0074] D. The sample for the engine oil resistance test is tinplate.

[0075] The acid resistance of various commercially available metal paints and the metal paints in the examples is compared and evaluated as shown in the following table:

[0076]

[0077] Note: A. The test method for acid resistance is: immerse the sample in a 5% concentration sulfuric acid solution.

[0078] B. The "acid resistance time" described in this table is the time required for the first bubble to appear on the paint film of the sample in an acid solution.

[0079] C. The method for judging acid resistance is: the shorter the acid resistance time, the worse the performance. The longer the acid resistance time, the better the performance.

[0080] D. The sample for acid resistance test is tinplate.

[0081] The alkali resistance of various commercially available metal paints and the metal paints in the examples is compared and evaluated as shown in the following table:

[0082]

[0083] Note: A. The test method for alkali resistance is: immerse the sample in 10% sodium hydroxide solution.

[0084] B. The "alkali resistance time" described in this table is the time required for the first bubble to appear on the paint film of the sample in an alkaline solution.

[0085] C. The evaluation method of alkali resistance is: the shorter the alkali resistance time, the worse the performance. The longer the alkali resistance time, the better the performance.

[0086] D. The sample for alkali resistance test is tinplate.

[0087] The above comparative performance evaluation covers 3 physical properties and 4 chemical properties. Overall, adhesion, salt spray resistance, oil resistance, acid resistance, and alkali resistance have all undergone disruptive changes. Hardness and impact resistance have also been greatly improved. The most important contribution is that the products under this technical solution solve the problem of the lack of universality of adhesion of conventional commercially available metal paints to various metal products, which greatly expands the application scope of metal paints.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A universal metal baking varnish, characterized in that: The universal metal baking paint comprises 30-40 parts of polyester resin, 20-30 parts of epoxy resin solution, 25-35 parts of amino resin, 0.5-5 parts of phosphate ester, 3-20 parts of solvent and 0.1-1 part of leveling agent.

2. The universal metal baking varnish according to claim 1, characterized in that: The polyester resin is a thermosetting polyester resin.

3. The universal metal baking varnish according to claim 1, characterized in that: The epoxy resin solution is a solution obtained by dissolving a solid epoxy resin in a solvent, wherein the solid epoxy resin is a bisphenol A epoxy resin.

4. The universal metal baking varnish according to claim 1, characterized in that: The amino resin is a melamine formaldehyde resin, which is a melamine formaldehyde resin obtained by mixing butanol and methanol for etherification.

5. The universal metal baking varnish according to claim 1, characterized in that: Phosphate esters are synthetic compounds of polyester and phosphoric acid.

6. The universal metal baking varnish according to claim 1, characterized in that: The leveling agent is a silicon-containing leveling agent, and the silicon-containing leveling agent is a polyester-modified organic silicon leveling agent.

7. The universal metal baking varnish according to claim 1, characterized in that: The solvent is an alcohol solvent or an ester solvent.

8. The universal metal baking varnish according to claim 3, characterized in that: The epoxy resin content in the epoxy resin solution is 70%.

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