A melamine resin coating using UV / thermal curing to form an IPN structure and a preparation method and use method thereof

Abstract

The present invention discloses a melamine resin coating that uses UV / thermal curing to form an IPN structure, and a preparation method and a use method thereof. The coating is prepared by mixing 100 parts of a bifunctional melamine resin with 5 to 20 parts of a photoinitiator; rapid gelation under UV conditions for 30 to 300 seconds, combined with thermal aging at 100 to 120°C for 5 to 18 minutes, takes a total of about 20 minutes to form a melamine resin coating with an IPN structure. Among them, the bifunctional melamine resin is mainly prepared by amination reaction of 126 parts of melamine, 243 parts of formaldehyde solution, and 50 to 150 parts of hydroxypropyl acrylate. The melamine resin coating provided by the present invention has outstanding advantages such as impact strength ≥240mm, pencil hardness ≥5H, wear resistance ≤0.4mg / 100 revolutions, contact angle >110°, water resistance ≥30h, and adhesion ≥10.0MPa. It has the outstanding advantages of short curing time, high production efficiency, excellent performance, etc. It solves the difficulties of direct coating application of conventional melamine resin and can be used in technical fields such as coatings, paints and coatings.

Description

Technical Field

[0001] The present invention relates to the field of surface protection, coating and coating technology, and in particular to a melamine resin coating which forms an IPN structure by UV / thermal curing and a preparation method and a use method thereof, and specifically to a new melamine resin coating which can be directly used as a coating and has outstanding advantages such as fast curing speed, high production efficiency and excellent coating performance. Background Art

[0002] Melamine-formaldehyde resin (melamine resin) is a typical thermosetting amino resin with the characteristics of continuous-natural slow curing. In industrial applications, the curing process of melamine resin mostly adopts thermal curing or acid / thermal curing, which has the disadvantages of cumbersome and time-consuming curing process, easy brittle cracking of the film layer, and acid corrosion of the substrate. This is far from the technical requirements of actual application and is not practical.

[0003] Ultraviolet (UV) curing technology has the advantages of high efficiency, energy saving, environmental protection, economy, and wide adaptability, and has been widely used in the field of coating and coating material technology. For example, Shakiba Dadkhah et al. compounded acrylic polyaniline / graphene oxide and used UV curing to prepare a composite coating with excellent corrosion resistance; Liu et al. synthesized a new silicone acrylate prepolymer with a tertiary amine group and four double bonds at each end and an alkoxymethyl acrylate titanium monomer, and used UV curing to prepare a coating, which effectively solved the oxygen barrier problem; Li et al. used UV curing to prepare a flexible self-healing epoxy acrylic coating, which has excellent comprehensive performance, a water contact angle of up to 155°, a self-healing rate of up to 97%, and a significant increase in wear resistance by 40%.

[0004] The above studies mainly focus on acrylate systems and use UV curing technology to achieve efficient preparation of resin coatings. In contrast, there are no reports on the use of UV curing technology to achieve efficient curing of melamine resin coatings.

[0005] To this end, the present invention provides a melamine resin coating that uses UV / thermal curing to form an IPN structure, and a preparation method and a use method thereof, which not only achieves a substantial breakthrough in the efficient curing of the melamine resin coating and the coating performance, but also opens up a practical technical route for the application of melamine resin in the coating field. Summary of the invention

[0006] The present invention provides a melamine resin coating which adopts UV / heat curing to form an IPN structure, and a preparation method and a use method thereof. The main purpose is to solve the problems that the conventional melamine resin curing process is complicated and the acid / heat curing method is corrosive to the substrate, and to provide a melamine resin coating which has excellent comprehensive performance, has an IPN structure, is impact-resistant, is intrinsically hydrophobic, and can be cured by UV / heat method.

[0007] The present invention provides a melamine resin coating that uses UV / heat curing to form an IPN structure, and a preparation method and a use method thereof, which have achieved new breakthroughs in the molecular structure of the melamine resin, the coating curing method, the coating performance, and the like.

[0008] According to a first aspect of the present invention, a bifunctional melamine resin is provided. The bifunctional melamine resin has a molecular structure design and contains two active reaction groups (-CH2OH, -CH=CH2). The resin is obtained by an amination reaction of 126 parts of melamine, 243 parts of formaldehyde solution (37%), and 50 to 150 parts of hydroxypropyl acrylate.

[0009] In some optional implementations of some embodiments, the amount of hydroxypropyl acrylate is preferably 115 parts.

[0010] In some optional implementations of some embodiments, the specific steps of the amination reaction are: 126 parts of melamine and 243 parts of formaldehyde solution (37%) are placed in a three-necked flask, heated to 90°C, and when the water tolerance point appears, cooled to 60°C, 50 to 150 parts of hydroxypropyl acrylate are added, stirred evenly, and reacted for 1.5 hours to obtain a bifunctional melamine resin.

[0011] According to a second aspect of the present invention, a melamine resin coating with an IPN structure formed by UV / heat curing is provided. The melamine resin coating is made of 100 parts of a bifunctional melamine resin, 5 to 20 parts of a photoinitiator, and a mixture of

[0012] The mixture is mixed evenly to prepare a melamine resin coating.

[0013] In some optional implementations of some embodiments, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxycyclohexyl phenyl ketone (184), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (754), and 2-isopropylthioxanthone (ITX). Preferably, the photoinitiator is 1-hydroxycyclohexyl phenyl ketone (184), and the usage amount is preferably 12 parts.

[0014] According to a third aspect of the present invention, there is provided a method for preparing a melamine resin coating having an IPN structure formed by UV / thermal curing, comprising: placing a melamine and formaldehyde solution in a three-necked flask, heating the solution to 90°C, and cooling the solution to 60°C until a water tolerance point appears, adding hydroxypropyl acrylate, stirring the mixture evenly, and reacting the mixture for 1.5 hours to obtain a bifunctional melamine resin; and mixing the bifunctional melamine resin and a photoinitiator according to a ratio to obtain the melamine resin coating.

[0015] According to a fourth aspect of the present invention, there is provided a method for using a melamine resin coating having an IPN structure formed by UV / thermal curing, the method comprising: a UV gelation process and a thermal aging process, wherein the UV gelation process specifically comprises: subjecting the melamine resin coating to UV gelation treatment under UV radiation conditions for a treatment time of 30 to 300 seconds to obtain a melamine resin coating film; and the thermal aging process specifically comprises: subjecting the melamine resin coating film to thermal aging at 90 to 120° C. for 5 to 18 minutes to obtain a melamine resin coating.

[0016] In some optional implementations of some embodiments, the melamine resin coating has an IPN structure.

[0017] In some optional implementations of some embodiments, the melamine resin coating has the following performance indicators: impact resistance ≥240mm, pencil hardness ≥5H, abrasion resistance ≤0.4mg / 100 turns, contact angle >110°, water resistance ≥30h, and adhesion ≥10.0MPa.

[0018] Furthermore, a UV / heat curing method is adopted to quickly realize the gelation process of the coating film under UV conditions, and the melamine resin coating can be obtained by heat curing at 100-120°C for 5-18 minutes. The whole operation process is simple, efficient and easy to operate. From the perspective of curing method, it innovates the conventional melamine resin acid / heat curing method, which is cumbersome, has a long cycle and is corrosive to the substrate.

[0019] The advantages and beneficial effects of the present invention are:

[0020] (1) The bifunctional melamine resin provided by the present invention contains two active reactive groups, -CH2OH and -CH=CH2

[0021] The reactive groups constitute the structural basis for its coating to adopt UV / heat curing mode to achieve rapid curing.

[0022] (2) The bifunctional melamine resin provided by the present invention can be cured quickly and efficiently by UV / heat curing.

[0023] (3) The bifunctional melamine resin provided by the present invention solves the restrictive problems of conventional melamine resins such as the cumbersome acid / heat curing method, the long cycle, and the corrosiveness to the substrate.

[0024] (4) After the melamine resin coating of the present invention is processed, the coating has excellent performance, impact strength ≥240mm, pencil hardness ≥5H, abrasion resistance ≤0.4mg / 100 revolutions, contact angle >110°, water resistance ≥30h, and adhesion ≥10.0MPa. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through specific implementation methods. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0026] It should be noted that the raw materials used in the various embodiments of the melamine resin coating for forming an IPN structure by UV / thermal curing provided by the present invention can all be obtained through market channels.

[0027] Example 1

[0028] The invention provides a preparation method of a bifunctional melamine resin. The bifunctional melamine resin is composed of 126 parts of melamine, 243 parts of formaldehyde solution (37%) and 50-150 parts of hydroxypropyl acrylate by mass, and is obtained through an amination reaction. The specific amination reaction process is: 126 parts of melamine and 243 parts of formaldehyde solution (37%) are placed in a three-necked flask, heated to 90°C, and cooled to 60°C until a water tolerance point appears, and 115 parts of hydroxypropyl acrylate are added, stirred evenly, and reacted for 1.5 hours to obtain the bifunctional melamine resin.

[0029] Furthermore, Examples 2 to 6 adopt a preparation method similar to that of Example 1 and are configured according to the ratios shown in Table 1 below. The difference between Examples 2 to 6 and Example 1 is that the raw materials and the ratios of the bifunctional melamine resin are different.

[0030] Table 1 Material ratio of Examples 1 to 6 (unit of measurement: mass fraction)

[0031]

[0032] Example 7

[0033] The present invention provides a method for preparing a melamine resin coating with an IPN structure formed by UV / heat curing. The method comprises the following steps: selecting the bifunctional melamine resin in Example 1, uniformly mixing 100 parts of the bifunctional melamine resin and 5 to 20 parts of a photoinitiator by weight, rapidly achieving a gelation process of the coating film under UV conditions, and thermally curing the coating film at 100 to 120° C. for 5 to 18 minutes to obtain a melamine resin coating with an IPN structure. The melamine resin coating has the following main performance indicators: impact resistance ≥240 mm, pencil hardness ≥5 H, abrasion resistance ≤0.4 mg / 100 revolutions, contact angle >110°, water resistance ≥30 h, and adhesion ≥10.0 MPa.

[0034] Furthermore, Examples 8 to 11 adopt a preparation method and a use method similar to Example 7, and are configured according to the ratios shown in Table 2 below. The difference between Examples 8 to 11 and Example 7 is that the raw materials of the melamine resin coating and their ratios are different, and the reaction conditions are different.

[0035] Table 2 Material ratio and reaction conditions of Examples 7 to 11 (unit of measurement: mass fraction)

[0036]

[0037]

[0038] Furthermore, the same test method was used to perform performance tests on Examples 7 to 11, and the test results are shown in Table 3 below.

[0039] Table 3 Performance parameters of Examples 7 to 11

[0040]

[0041] As can be seen from Table 3, the melamine resin coating provided by the present invention, which adopts UV / thermal curing to form an IPN structure, has the following main performance indicators: impact resistance ≥240mm, pencil hardness ≥5H, abrasion resistance ≤0.4mg / 100 revolutions, contact angle >110°, water resistance ≥30h, and adhesion ≥10.0MPa.

[0042] Obviously, it should be understood by those skilled in the art that the above-mentioned various steps of the present invention can be performed in a manner different from the present invention, and the simulation method and experimental equipment include but are not limited to the above description. The above-mentioned various steps of the present invention can be performed in an order different from that here in some cases, and the steps shown or described above can be performed separately. Therefore, the present invention is not limited to any specific combination of hardware and software.

[0043] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A melamine resin coating using UV / thermal curing to form an IPN structure, characterized in that: The melamine resin coating is composed of the following raw materials in parts by weight: 100 parts of bifunctional melamine resin and 5-20 parts of photoinitiator; the bifunctional melamine resin is composed of the following raw materials in parts by weight: 126 parts of melamine, 243 parts of formaldehyde solution, and 50-150 parts of hydroxypropyl acrylate, the concentration of the formaldehyde solution is 37%, and the bifunctional melamine resin is synthesized through an amination reaction.

2. The melamine resin coating for forming an IPN structure by UV / heat curing according to claim 1, characterized in that: The amount of the hydroxypropyl acrylate is 115 parts.

3. The melamine resin coating for forming an IPN structure by UV / heat curing according to claim 1, characterized in that: The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and 2-isopropylthioxanthone.

4. The melamine resin coating for forming an IPN structure by UV / heat curing according to claim 3, characterized in that: The photoinitiator is 12 parts of 1-hydroxycyclohexyl phenyl ketone.

5. A method for preparing a melamine resin coating having an IPN structure by UV / thermal curing according to any one of claims 1 to 4, characterized in that: include: Place melamine and formaldehyde solution in a three-necked flask, heat to 90°C, wait until water tolerance point appears, cool to 60°C, add hydroxypropyl acrylate, stir evenly, react for 1.5 hours, and obtain bifunctional melamine resin; The bifunctional melamine resin and the photoinitiator are mixed according to a proportion to obtain the melamine resin coating.

6. A method for using a melamine resin coating with an IPN structure formed by UV / thermal curing according to any one of claims 1 to 4, characterized in that: include: UV gelation process and thermal aging process, wherein the UV gelation process specifically includes: performing UV gelation treatment on the melamine resin coating under UV radiation conditions for a treatment time of 30 to 300 seconds to obtain a melamine resin coating film; the thermal aging process specifically includes: placing the melamine resin coating film under 90 to 120° C. for thermal aging for 5 to 18 minutes to obtain a melamine resin coating.

7. The method for using the melamine resin coating having an IPN structure formed by UV / thermal curing according to claim 6, characterized in that: The melamine resin coating has an IPN structure.

8. The method for using the melamine resin coating having an IPN structure formed by UV / thermal curing according to claim 6, characterized in that: The melamine resin coating has the following performance indicators: impact resistance ≥240 mm, pencil hardness ≥5H, abrasion resistance ≤0.4 mg / 100 revolutions, contact angle >110°, water resistance ≥30 h, and adhesion ≥10.0 MPa.

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