A dual-curing stamping primer and its preparation method and application

Abstract

The present invention discloses a dual-curing stamping primer, its preparation method and application, which relate to the technical field of coatings. A dual-curing stamping primer includes component A and component B; the component A includes the following preparation raw materials by weight: 3-12 parts of solvent-containing acrylate oligomer, 8-17 parts of polyurethane polycarbonate resin, 3-12 parts of polyurethane acrylate resin, 3-7 parts of bifunctional acrylate monomer, 8-22 parts of hydroxyl-containing UV polyurethane resin, 1-2 parts of photoinitiator, 0-0.5 part of leveling agent, 50-60 parts of diluent; the component B includes the following preparation raw materials by weight: 65-75 parts of aliphatic polyisocyanate, 25-35 parts of solvent. It can stably adhere to the surface of the epoxy glass fiber composite board, has strong adhesion, good covering property and boiling water resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a dual-curing stamping primer and its preparation method and application. Background Art

[0002] With the popularization of electronic products such as mobile phones and tablets, consumers have higher and higher requirements for the appearance and texture of the outer shells of electronic products. The stamping process is a common process in the processing of the outer shells of electronic products. Epoxy glass fiber composite board is a common processing raw material for the outer shells of electronic products, which combines the adhesiveness of epoxy resin and the reinforcement effect of glass fiber. Compared with plastic plates such as PC and PMMA, the epoxy glass fiber composite board has good basic corrosion resistance and high strength, and it is difficult for ordinary primers to form stable adhesion on its surface, and there are problems such as poor covering property, adhesion, and boiling water resistance.

[0003] Therefore, it is very important to provide a primer suitable for the stamping process of epoxy glass fiber composite board and having good covering property, adhesion, and boiling water resistance. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a dual-curing stamping primer with good covering property, adhesion, and boiling water resistance.

[0005] The present invention also provides a preparation method of the above dual-curing stamping primer.

[0006] The present invention also provides an application of the above dual-curing stamping primer.

[0007] A dual-curing stamping primer according to an embodiment of the first aspect of the present invention includes component A and component B;

[0008] Component A includes the following preparation raw materials by weight: 3-12 parts of solvent-containing acrylate oligomer, 8-17 parts of polyurethane polycarbonate resin, 3-12 parts of polyurethane acrylate resin, 3-7 parts of difunctional acrylate monomer, 8-22 parts of hydroxyl-containing UV polyurethane resin, 1-2 parts of photoinitiator, 0-0.5 part of leveling agent, 50-60 parts of diluent;

[0009] Component B includes the following preparation raw materials by weight: 65-75 parts of aliphatic polyisocyanate, 25-35 parts of solvent.

[0010] The dual-curing stamping primer according to the embodiment of the present invention is specially developed for epoxy glass fiber composite board and has at least the following beneficial effects:

[0011] The dual-curing stamping primer of the embodiment has strong adhesion, good covering property and boiling water resistance, and at the same time has good wettability, which can avoid appearance defects such as oil vortices caused by different surface dyne values of the substrate. It overcomes the characteristics of poor adhesion, unstable comprehensive performance, abnormal oil vortices in the spraying appearance, etc. when the UV primer is directly coated on the surface of the epoxy glass fiber composite board, and is applicable to the stamping process, has a good stamping effect, the stamping pattern texture is clear, is easy to stamp and demold during the stamping process; after stamping the inner pattern, other coatings are well adhered to the coating surface.

[0012] According to some embodiments of the present invention, the component A comprises the following preparation raw materials by weight: 5-10 parts of solvent-containing acrylate oligomer, 10-15 parts of polyurethane polycarbonate resin, 5-10 parts of polyurethane acrylate resin, 4-6 parts of bifunctional acrylate monomer, 10-20 parts of hydroxyl-containing UV polyurethane resin, 1.3-1.7 parts of photoinitiator, 0.1-0.3 part of leveling agent, 52-55 parts of diluent;

[0013] The component B comprises the following preparation raw materials by weight: 68-72 parts of aliphatic polyisocyanate, 28-32 parts of solvent.

[0014] According to some embodiments of the present invention, the mass ratio of the component A to the component B is 100: (3-8). For example: it can be 100: 3, 100: 3.5, 100: 4, 100: 4.5, 100: 5, 100: 5.5, 100: 6, 100: 6.5, 100: 7, 100: 7.5 or 100: 8.

[0015] According to some embodiments of the present invention, the solid content of the solvent-containing acrylate oligomer is 55%-65%. For example: it can be 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64% or 65%.

[0016] According to some embodiments of the present invention, the viscosity of the solvent-containing acrylate oligomer is 1500 mPa·s / 50°C - 3000 mPa·s / 50°C. For example, it can be 1500 mPa·s / 50°C, 1600 mPa·s / 50°C, 1700 mPa·s / 50°C, 1800 mPa·s / 50°C, 1900 mPa·s / 50°C, 2000 mPa·s / 50°C, 2100 mPa·s / 50°C, 2200 mPa·s / 50°C, 2300 mPa·s / 50°C, 2400 mPa·s / 50°C, 2500 mPa·s / 50°C, 2600 mPa·s / 50°C, 2700 mPa·s / 50°C, 2800 mPa·s / 50°C, 2900 mPa·s / 50°C or 3000 mPa·s / 50°C.

[0017] According to some embodiments of the present invention, the grades of the solvent-containing acrylate oligomer include at least one of Changxing 6071 and Changxing 6175-3.

[0018] According to some embodiments of the present invention, the solid content of the polyurethane polycarbonate resin is 95% - 100%. For example, it can be 95%, 96%, 97%, 98%, 99% or 100%.

[0019] According to some embodiments of the present invention, the viscosity of the polyurethane polycarbonate resin is 6000 mPa·s / 60°C - 25000 mPa·s / 60°C. For example, it can be 6000 mPa·s / 60°C, 8000 mPa·s / 60°C, 10000 mPa·s / 60°C, 12000 mPa·s / 60°C, 14000 mPa·s / 60°C, 16000 mPa·s / 60°C, 18000 mPa·s / 60°C, 20000 mPa·s / 60°C, 22000 mPa·s / 60°C, 24000 mPa·s / 60°C or 250000 mPa·s / 60°C.

[0020] According to some embodiments of the present invention, the functionality of the polyurethane polycarbonate resin is 2 - 3.

[0021] According to some embodiments of the present invention, the grades of the polyurethane polycarbonate resin include HP1218.

[0022] According to some embodiments of the present invention, the solid content of the polyurethane acrylate resin is 95% - 100%. For example, it can be 95%, 96%, 97%, 98%, 99% or 100%.

[0023] According to some embodiments of the present invention, the viscosity of the polyurethane acrylate resin is 4000 mPa·s / 60°C - 10000 mPa·s / 60°C. For example, it can be 4000 mPa·s / 60°C, 5000 mPa·s / 60°C, 6000 mPa·s / 60°C, 7000 mPa·s / 60°C, 8000 mPa·s / 60°C, 9000 mPa·s / 60°C or 10000 mPa·s / 60°C.

[0024] According to some embodiments of the present invention, the functionality of the polyurethane acrylate resin is 2 - 3.

[0025] According to some embodiments of the present invention, the grades of the polyurethane acrylate resin include at least one of CR90631 and CN965.

[0026] According to some embodiments of the present invention, the difunctional acrylate monomer includes at least one of tripropylene glycol diacrylate and dipropylene glycol triacrylate (TPGDA).

[0027] According to some embodiments of the present invention, the solid content of the hydroxyl - containing UV polyurethane resin is 75% - 100%. For example, it can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%.

[0028] According to some embodiments of the present invention, the viscosity of the hydroxyl - containing UV polyurethane resin is 1000 mPa·s / 25°C - 15000 mPa·s / 25°C. For example, it can be 1000 mPa·s / 25°C, 2000 mPa·s / 25°C, 3000 mPa·s / 25°C, 4000 mPa·s / 25°C, 5000 mPa·s / 25°C, 6000 mPa·s / 25°C, 7000 mPa·s / 25°C, 8000 mPa·s / 25°C, 9000 mPa·s / 25°C, 10000 mPa·s / 25°C, 11000 mPa·s / 25°C, 12000 mPa·s / 25°C, 13000 mPa·s / 25°C, 14000 mPa·s / 25°C or 15000 mPa·s / 25°C.

[0029] According to some embodiments of the present invention, the functionality of the hydroxyl - containing UV polyurethane resin is 2 - 4. For example, it can be 2, 3 or 4.

[0030] According to some embodiments of the present invention, the hydroxyl value of the hydroxyl-containing UV polyurethane resin is 10 mg KOH / g - 120 mg KOH / g. For example, it can be 10 mg KOH / g, 15 mg KOH / g, 20 mg KOH / g, 25 mg KOH / g, 30 mg KOH / g, 40 mg KOH / g, 45 mg KOH / g, 50 mg KOH / g, 55 mg KOH / g, 60 mg KOH / g, 65 mg KOH / g, 70 mg KOH / g, 75 mg KOH / g, 80 mg KOH / g, 85 mg KOH / g, 90 mg KOH / g, 95 mg KOH / g, 100 mg KOH / g, 105 mg KOH / g, 110 mg KOH / g, 115 mg KOH / g, 120 mg KOH / g.

[0031] According to some embodiments of the present invention, the grades of the hydroxyl-containing UV polyurethane resin include at least one of L-8464, B-6210, and B-6263.

[0032] According to some embodiments of the present invention, the photoinitiator includes at least one of photoinitiator 184, photoinitiator TPO, and photoinitiator 1173.

[0033] According to some embodiments of the present invention, the photoinitiator includes photoinitiator 184 and photoinitiator TPO. Photoinitiator 184 and photoinitiator TPO used in combination have a wide absorption range, with an effective absorption peak of 280 nm - 420 nm, high light initiation efficiency, fast curing speed, and can be cured and formed under the LED light source of the stamping equipment.

[0034] According to some embodiments of the present invention, the mass ratio of photoinitiator 184 to photoinitiator TPO is (5 - 8):1. For example, it can be 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, or 8:1.

[0035] According to some embodiments of the present invention, the grades of the leveling agent include at least one of BYK358N and BYK-354.

[0036] According to some embodiments of the present invention, the diluent includes at least one of methyl isobutyl ketone, isopropyl acetate, butyl acetate, and isobutyl isobutyrate.

[0037] According to some embodiments of the present invention, the diluent includes methyl isobutyl ketone, isopropyl acetate, butyl acetate, and isobutyl isobutyrate.

[0038] According to some embodiments of the present invention, the mass ratio of methyl isobutyl ketone, isopropyl acetate, butyl acetate, and isobutyl isobutyrate is (0.5 - 3):(0.5 - 3):(0.5 - 3):1.

[0039] According to some embodiments of the present invention, the mass ratio of methyl isobutyl ketone, isopropyl acetate, butyl acetate, and isobutyl isobutyrate is (1.5 - 2.2):(2.3 - 3):(1 - 1.5):1.

[0040] According to some embodiments of the present invention, the NCO content of the aliphatic polyisocyanate is 15% - 20%. For example, it can be 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5% or 20%.

[0041] According to some embodiments of the present invention, the aliphatic polyisocyanate is hexamethylene diisocyanate trimer. The grades of the aliphatic polyisocyanate include at least one of Covestro N75 and Covestro N3390.

[0042] According to some embodiments of the present invention, the solvent includes at least one of butyl acetate, methyl isobutyl ketone, and isopropyl acetate.

[0043] According to the preparation method of the dual-curing stamping primer described in the first aspect of the second aspect of the embodiments of the present invention, the method includes the following steps:

[0044] Mix the component A and the component B to obtain the dual-curing stamping primer.

[0045] The preparation method of the dual-curing stamping primer according to the embodiments of the present invention has at least the following beneficial effects:

[0046] This preparation method has simple steps and is easy to operate. It can be made without complex equipment and is suitable for large-scale industrial production.

[0047] According to some embodiments of the present invention, the preparation method of the component A includes the following steps:

[0048] Prepare a mixture of each preparation raw material and separate the liquid phase. The liquid phase is the component A.

[0049] According to some embodiments of the present invention, the preparation method of the component A includes the following steps:

[0050] A1) Prepare a mixed solution of the photoinitiator, leveling agent, and part of the diluent;

[0051] A2) Prepare a mixture of the solvent-containing acrylate oligomer, polyurethane polycarbonate resin, polyurethane acrylate resin, difunctional acrylate monomer, and hydroxyl group-containing UV polyurethane resin;

[0052] A3) Stir the mixture evenly with the mixed solution and the remaining diluent in sequence, and separate the liquid phase, which is the Component A.

[0053] According to some embodiments of the present invention, the stirring time for preparing the mixture in A2) is 20 - 30 minutes. For example, it can be 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or 30 minutes.

[0054] According to some embodiments of the present invention, the stirring speed for preparing the mixture in A2) is 800 - 1200 revolutions per minute. For example, it can be 800 revolutions per minute, 850 revolutions per minute, 900 revolutions per minute, 950 revolutions per minute, 1000 revolutions per minute, 1050 revolutions per minute, 1100 revolutions per minute, 1150 revolutions per minute, or 1200 revolutions per minute.

[0055] According to some embodiments of the present invention, the stirring time for stirring with the mixed solution in A3) is 20 - 30 minutes. For example, it can be 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or 30 minutes.

[0056] According to some embodiments of the present invention, the stirring speed for stirring with the mixed solution in A3) is 500 - 800 revolutions per minute. For example, it can be 500 revolutions per minute, 550 revolutions per minute, 600 revolutions per minute, 650 revolutions per minute, 700 revolutions per minute, 750 revolutions per minute, or 800 revolutions per minute.

[0057] According to some embodiments of the present invention, the stirring time for stirring with the remaining diluent in A3) is 10 - 20 minutes. For example, it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0058] According to some embodiments of the present invention, the stirring speed for stirring with the remaining diluent in A3) is 300 - 500 revolutions per minute. For example, it can be 300 revolutions per minute, 350 revolutions per minute, 400 revolutions per minute, 450 revolutions per minute, or 500 revolutions per minute.

[0059] According to some embodiments of the present invention, the preparation method of the Component B includes the following steps:

[0060] In an inert gas environment, a mixture of each preparation raw material is prepared, and the liquid phase is separated, and the liquid phase is the component B. The inert gas can prevent water vapor in the air from reacting with the aliphatic polyisocyanate and causing failure.

[0061] According to some embodiments of the present invention, in the preparation method of the component B, the stirring time for preparing the mixture is 10-20 minutes. For example: it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes.

[0062] According to some embodiments of the present invention, in the preparation method of the component B, the stirring speed for preparing the mixture is 300-800 revolutions per minute. For example: it can be 300 revolutions per minute, 350 revolutions per minute, 400 revolutions per minute, 450 revolutions per minute, 500 revolutions per minute, 550 revolutions per minute, 600 revolutions per minute, 650 revolutions per minute, 700 revolutions per minute, 750 revolutions per minute or 800 revolutions per minute.

[0063] Application of the dual-curing stamping primer as described in the first aspect embodiment of the third aspect embodiment of the present invention in the processing of epoxy glass fiber composite boards.

[0064] According to some embodiments of the present invention, the dual-curing stamping primer can be used for surface stamping of mobile phone battery covers, tablet computer battery covers, etc.

[0065] According to some embodiments of the present invention, the method of applying the dual-curing stamping primer includes the following steps:

[0066] Spray the dual-curing stamping primer onto the epoxy glass fiber composite board, perform stamping texture, and cure to form a primer layer.

[0067] According to some embodiments of the present invention, the film thickness of the sprayed dual-curing stamping primer is 20 μm to 30 μm.

[0068] According to some embodiments of the present invention, the processing conditions of the stamping texture include: infrared leveling temperature 55°C to 65°C, time 5 min to 8 min; UV curing energy is: 400 mJ / cm 2 ~600 mJ / cm 2 .

[0069] According to some embodiments of the present invention, the preparation method may further include: spraying color paint on the primer layer and curing to form a color paint layer; and / or, spraying topcoat and curing to form a topcoat layer.

[0070] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. Detailed implementation mode

[0071] The following will clearly and completely describe the concept and technical effects generated by the present invention in combination with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of protection of the present invention.

[0072] For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0073] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to an integer, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0074] "Part by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass part of component A is a parts and the mass part of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from mass fraction, the sum of the mass parts of all components is not limited to 100 parts.

[0075] The solvent-containing acrylate oligomer has good compatibility, good adhesion, fast drying speed, good surface drying effect, good finger-touch effect, clear embossing texture and excellent comprehensive performance.

[0076] The solvent-containing acrylate oligomer used in the embodiment is a product with the brand number 6071 produced by Changxing Chemical Industry Co., Ltd., with a solid content of 60% and a viscosity of 1700 - 2100 mPa·s / 50°C.

[0077] The chemical bonds in the molecular structure of the polyurethane polycarbonate resin are stable, and the reaction speed is fast, which can make the primer better adhere to the epoxy glass fiber composite board, effectively improving the photocuring speed, flexibility and heat and humidity resistance of the primer.

[0078] The polyurethane polycarbonate resin used in the examples is a product with the brand name HP1218 produced by Guangdong Haohui New Materials Co., Ltd., with a solid content of 100%, a viscosity of 8000 - 22000 mPa·s / 60°C, and a functionality of 2.

[0079] The polyurethane acrylate resin with good leveling and fullness, full solid content, and low viscosity has good fullness and excellent wettability, with a good leveling effect. Appropriate addition can increase the leveling and fullness of the paint film, and at the same time, it will not make the paint film too hard, resulting in problems such as difficult adhesion of the top coat to the primer.

[0080] The polyurethane acrylate resin used in the examples is a product with the brand name CR90631 produced by Guangdong Haohui New Materials Co., Ltd., with a solid content of 100%, a viscosity of 4800 - 9200 mPa·s / 60°C, and a functionality of 2.

[0081] The bifunctional acrylic monomer has a fast reaction rate, certain bite force, can promote the adhesion of the coating to the substrate, and has a low viscosity and fast flow rate, which can achieve a good leveling effect. If the functionality is too low, the reaction rate will be slower; if the functionality is too high, the reaction rate will be too fast, the hardness of the paint film surface will be too high, it will be difficult for the top coat of the primer to adhere, and it will also lead to problems such as poor adhesion to the substrate.

[0082] The bifunctional acrylic monomer used in the examples is tripropylene glycol diacrylate, and the product with the brand name EM223 produced by Changxing Chemical Industry Co., Ltd. is used.

[0083] The hydroxyl - containing UV polyurethane resin is a dual - curing UV resin that can meet both UV light curing and baking - type curing at the same time. Its molecular structure contains hydroxyl groups in the bonds, and when paired with an isocyanate curing agent, it has excellent comprehensive properties after curing.

[0084] The hydroxyl - containing UV polyurethane resin used in the examples is a product with the brand name L - 8464 produced by Guangdong Lancol New Materials Co., Ltd., with a solid content of 85%, a viscosity of 6000 - 11000 mPa·s / 25°C, a hydroxyl value of 70 mg KOH / g, and a functionality of 4.

[0085] The leveling agent used in the examples is a product with the brand name BYK358N produced by BYK Chemie GmbH.

[0086] The aliphatic polyisocyanate used in the examples is Covestro N75, and the NCO content is (16.5 ± 0.3)%.

[0087] Examples

[0088] This example provides 3 kinds of dual - curing stamping primers (Examples 1 - 3). By weight, the formula is shown in Table 1.

[0089] Table 1

[0090]

[0091] This example also provides a preparation method for the dual-curing stamping primer of Example 1, and the steps are as follows:

[0092] (1) Weigh half of the mass of the diluent, dissolve the photoinitiator and the leveling agent to obtain a mixed solution. Add the solvent-based acrylate oligomer, polyurethane polycarbonate resin, polyurethane acrylate resin, difunctional acrylate monomer, and hydroxyl-containing UV polyurethane resin to the reaction kettle in proportion, and disperse (the stirring time is 25 minutes, and the stirring speed is 1000 revolutions per minute); continue to add the mixed solution and disperse (the stirring time is 20 minutes, and the stirring speed is 800 revolutions per minute); add the remaining diluent to the reaction kettle and stir evenly (the stirring time is 10 minutes, and the stirring speed is 500 revolutions per minute), filter, and collect the liquid phase to obtain Component A. (2) Under a nitrogen atmosphere, mix the aliphatic polyisocyanate and butyl acetate, stir and disperse for 10 min (the stirring speed is 500 revolutions per minute), perform solid-liquid separation, and collect the liquid phase to obtain Component B. (3) Mix Component A and Component B in a mass ratio of 100:5 to obtain the dual-curing stamping primer.

[0093] The preparation methods for the dual-curing stamping primers of Examples 2 to 3 are the same as that of Example 1.

[0094] Comparative Example

[0095] This example provides 6 kinds of dual-curing stamping primers (Comparative Examples 1 to 6). By weight, the formula is shown in Table 2.

[0096] Table 2

[0097]

[0098] The preparation methods for the dual-curing stamping primers of Comparative Examples 1 to 6 are the same as that of Example 1.

[0099] Test Example

[0100] Apply the dual-curing stamping primers of Examples 1 to 3 and Comparative Examples 1 to 6 to the epoxy glass fiber composite board respectively, and evaluate the performance of the obtained stamping products. The specific coating process is as follows:

[0101] After wiping the surface stains and dust spots of the epoxy glass fiber composite board with alcohol, use a spraying device to coat the dual-curing stamping primers of Examples 1 to 3 and Comparative Examples 1 to 6 on the surface of the epoxy glass fiber composite board respectively (the sprayed film thickness is 25 μm), the infrared leveling temperature is 55°C, and the time is 5 min; the UV curing energy is: 500 mJ / cm 2, a dual-curing stamping primer coating is obtained. Then, it is paired with SF222 series color paints and SF132 series topcoats (Hunan Songjing New Materials Co., Ltd., refer to the corresponding instructions for usage), and a stamped product is obtained after curing.

[0102] (1) Compare the clarity of the stamped texture and the covering effect on the material grid print of each stamped product.

[0103] (2) Adhesion test: Use a sharp blade (blade angle is 20° - 30°, blade thickness is 0.43 ± 0.03 mm) to draw 1 mm × 1 mm small grids on the surface of the test sample according to the film thickness specification; Stick the NICHIBAN CT405AP-24 tape on the tested small grids, press the tape flat above the grid area with the back of the fingernail, and let it stand for (90 ± 30) s; Grab one end of the tape with your hand and quickly (0.5 s - 1 s) tear off the tape in the opposite direction at a 60° angle, and check the coating peeling condition. The evaluation criteria are as follows: 5B: No peeling within the grid; 4B: The coating peeling at the cutting intersection is < 5%; 3B: 5% < the coating peeling at the cutting intersection < 15%; 2B: 15% < the coating peeling at the cutting intersection < 35%; 1B: 35% < the coating peeling at the cutting intersection < 65%; 0B grade: The coating peeling at the cutting intersection > 65%.

[0104] (3) Conventional boiling water test: Wipe the surface of the test sample clean with a lint-free cloth; Add pure water to the water bath and heat it to and maintain it at 80°C ± 1°C; Immerse the test sample completely in the hot water, take it out after 40 minutes, and let it stand at room temperature for 10 minutes; Check whether there are abnormalities such as cracking, blistering, and paint film discoloration on the surface of the sample coating, and conduct an adhesion test on the surface (the method is the same as (2)).

[0105] (4) Severe boiling water test: Wipe the surface of the test sample clean with a lint-free cloth; Add pure water to the water bath and heat it to and maintain it at 99°C ± 1°C; Immerse the test sample completely in the hot water, take it out after 5 hours, and let it stand at room temperature for 10 minutes; Check whether there are abnormalities such as cracking, blistering, and paint film discoloration on the surface of the sample coating, and conduct an adhesion test on the surface (the method is the same as (2)).

[0106] The test results are shown in Table 3.

[0107] Table 3

[0108]

[0109] The adhesion, covering property after stamping, and boiling water resistance of the paint films formed by the dual-curing stamping primers in Examples 1 - 3 are good, and the comprehensive performance is excellent.

[0110] In Comparative Examples 1, 2, and 5, the addition amount of the hydroxyl group-containing UV polyurethane resin in the dual-curing stamping primer is small, and the water boiling resistance is significantly deteriorated. This may be because the reaction of an appropriate amount of the hydroxyl group-containing UV polyurethane resin with the aliphatic polyisocyanate can effectively improve the crosslinking density of the paint film, making the paint film have better heat and humidity resistance. Among them, the reason why the adhesion in the conventional water boiling test of Comparative Example 5 is better than that in the conventional test may be that the hydroxyl group-containing UV polyurethane resin is not added in the dual-curing stamping primer, its bite on the epoxy glass fiber composite board is not firm, and the resins contained are all low-functional group resins, with a slow reaction. Moreover, after the topcoat is sprayed, the curing shrinkage and pulling of the topcoat make the adhesion of the paint film worse. And "boiling in water at 80 °C for 40 min" is also a process of releasing stress for the paint film, resulting in better toughness and adhesion of the paint film.

[0111] In the dual-curing stamping primer of Comparative Example 3, the addition amount of the hydroxyl group-containing UV polyurethane resin is too much, resulting in insufficient fullness of the dual-curing stamping primer, poor leveling property, and poor covering property after stamping on the substrate.

[0112] The dual-curing stamping primer of Comparative Example 4 does not contain polyurethane polycarbonate resin, and the covering property after stamping and the adhesion after the conventional water boiling test are not good. This may be because the carbon chain structure in the molecular structure of the polyurethane polycarbonate resin is relatively stable and not easily decomposed, which can improve the heat resistance and water resistance of the paint film.

[0113] The dual-curing stamping primer of Comparative Example 6 does not contain bifunctional acrylic monomers, and the adhesion and water boiling resistance are not good. This may be because the bifunctional acrylic monomers have a small molecular weight and strong etching ability, and can effectively penetrate and etch the substrate, improving the adhesion of the paint film.

[0114] In summary, only using two of the hydroxyl group-containing UV polyurethane resin, polyurethane polycarbonate resin, and bifunctional acrylic monomers cannot solve the problems of poor adhesion of the primer on the surface of the epoxy glass fiber composite board and poor water boiling resistance of the formed paint film.

[0115] In the dual-curing stamping primer of the solution of the present invention, the hydroxyl groups in the hydroxyl-containing UV polyurethane resin can undergo a polymerization reaction with isocyanate bonds, enhancing the curing speed, strength and toughness of the paint film. They can also combine with the surface groups of the epoxy glass fiber composite board, further increasing the adhesion of the paint film. The polyurethane polycarbonate resin contains carbonate bonds, increasing the intermolecular interaction force, making the macromolecular bonds closer to each other, increasing the rigidity of the polymer, and improving the water-boiling resistance of the paint film. The bifunctional acrylic monomer improves the fluidity of the dual-curing stamping primer and its wetting and leveling effects on the substrate surface, has a micro-corrosion effect on the substrate surface, further increases the adhesion of the paint film, and forms free radicals and undergoes a polymerization reaction under the action of a photoinitiator. After the components undergo polymerization, a paint film is formed. Through the synergistic effect of the hydroxyl-containing UV polyurethane resin, the polyurethane polycarbonate resin, and the bifunctional acrylic monomer, the adhesion of the primer on the surface of the epoxy glass fiber composite board and the water-boiling resistance of the paint film are significantly improved.

[0116] The embodiments of the present invention have been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention.

Claims

1. A dual-curing stamping primer, characterized in that, It includes Component A and Component B; Component A includes the following preparation raw materials by weight: 3 - 12 parts of solvent-containing acrylate oligomer, 8 - 17 parts of polyurethane polycarbonate resin, 3 - 12 parts of polyurethane acrylate resin, 3 - 7 parts of difunctional acrylate monomer, 8 - 22 parts of hydroxyl-containing UV polyurethane resin, 1 - 2 parts of photoinitiator, 0 - 0.5 part of leveling agent, 50 - 60 parts of diluent; Component B includes the following preparation raw materials by weight: 65 - 75 parts of aliphatic polyisocyanate, 25 - 35 parts of solvent.

2. The dual-curing stamping primer according to claim 1, characterized in that, Component A includes the following preparation raw materials by weight: 5 - 10 parts of solvent-containing acrylate oligomer, 10 - 15 parts of polyurethane polycarbonate resin, 5 - 10 parts of polyurethane acrylate resin, 4 - 6 parts of difunctional acrylate monomer, 10 - 20 parts of hydroxyl-containing UV polyurethane resin, 1.3 - 1.7 parts of photoinitiator, 0.1 - 0.3 part of leveling agent, 52 - 55 parts of diluent; Component B includes the following preparation raw materials by weight: 68 - 72 parts of aliphatic polyisocyanate, 28 - 32 parts of solvent.

3. The dual-curing stamping primer according to claim 1, wherein The mass ratio of Component A to Component B is 100: 3 - 8.

4. The double-curing stamping primer according to claim 1, characterized in that The viscosity of the solvent-containing acrylate oligomer is 1500 mPa·s / 50℃ - 3000 mPa·s / 50℃; and / or, the solid content of the solvent-containing acrylate oligomer is 55% - 65%.

5. The double-curing stamping primer according to claim 1, wherein The functionality of the polyurethane polycarbonate resin is 2 - 3; and / or, the solid content of the polyurethane polycarbonate resin is 95% - 100%; and / or, the viscosity of the polyurethane polycarbonate resin is 6000 mPa·s / 60℃ - 25000 mPa·s / 60℃.

6. The double-curing stamping primer according to claim 1, characterized in that, The functionality of the polyurethane acrylate resin is 2 - 3; and / or, the solid content of the polyurethane acrylate resin is 95% - 100%; and / or, the viscosity of the polyurethane acrylate resin is 4000 mPa·s / 60℃ - 10000 mPa·s / 60℃.

7. The double-curing stamping primer according to claim 1, characterized in that, The difunctional acrylate monomer includes at least one of tripropylene glycol diacrylate and TPGDA; and / or, the photoinitiator includes at least one of photoinitiator 184, photoinitiator TPO, and photoinitiator 1173; and / or, the grade of the leveling agent includes at least one of BYK358N and BYK354; and / or, the diluent includes at least one of methyl isobutyl ketone, isopropyl acetate, butyl acetate, and isobutyl isobutyrate; and / or, the grade of the aliphatic polyisocyanate includes at least one of Covestro N75 and Covestro N3390; and / or, the solvent includes at least one of butyl acetate, methyl isobutyl ketone, and isopropyl acetate.

8. The double-curing stamping primer according to claim 1, characterized in that, The functionality of the hydroxyl group-containing UV polyurethane resin is 2-4; and / or, the hydroxyl value of the hydroxyl group-containing UV polyurethane resin is 10 mg KOH / g - 120 mg KOH / g; and / or, the solid content of the hydroxyl group-containing UV polyurethane resin is 75% - 100%; and / or, the viscosity of the hydroxyl group-containing UV polyurethane resin is 1000 mPa·s / 25°C - 15000 mPa·s / 25°C.

9. The preparation method of the dual-curing stamping primer according to any one of claims 1 to 8, characterized in that, Comprising the following steps: Mix the component A and the component B to obtain the dual-curing embossing primer.

10. Application of the dual-curing embossing primer according to any one of claims 1 to 8 in the processing of epoxy glass fiber composite boards.

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