A fully solid zero-dispersion UV roller coating clear topcoat

Abstract

The present invention relates to the technical field of chemical UV coatings, and discloses a fully solid zero-gloss UV roller coating clear topcoat. In this invention, the bifunctional polyurethane acrylate resin plays a film-forming role, reducing the gloss of the traditional process paint film by 30%. The hexafunctional polyurethane acrylate resin assists in improving the crosslinking density of the paint. A special reactive monomer with amphiphilic and polymerizable characteristics, in combination with the characteristic of poor compatibility of the uncured paint liquid raw materials, forms a microscopically uneven paint film with convex and concave surfaces on the surface of the coating film, ensuring that the gloss after film curing reaches zero gloss. The addition of DPHA monomer, HDDA monomer, and TPGDA monomer speeds up the crosslinking reaction. In combination with a photoinitiator, it optimizes and balances the surface drying and internal drying of the paint, controls the HLB value and particle diameter of the wetting and dispersing agent, cooperates with an antifoaming agent to defoam, a leveling agent to level, and matte powder to achieve extinction and stabilize the paint viscosity, realizing a stable and consistent zero-gloss effect of the paint film without adding equipment and processes, and using a conventional roller coater for production, which simplifies production, saves energy, and has low costs.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical UV coatings, and particularly to a fully solid-content zero-spectroscopic UV roller coating clear topcoat. Background Art

[0002] UV coatings are favored by more and more users due to reasons such as environmental protection, high efficiency, and economy, and their application fields are also becoming more and more extensive. UV coatings are used in floors, furniture, electronics, hardware, building materials, and even new energy batteries. With the continuous expansion of the UV coating market, people's performance requirements and construction requirements for UV coatings are getting higher and higher. They require both good workability and good physical and chemical properties of UV coatings, and at the same time, they require UV coatings to have good decorative and protective effects. Currently, matte effect coatings are very popular in the market, and coatings with an extremely matte film effect, that is, zero-spectroscopic effect coatings, are even more sought after by consumers.

[0003] The decrease in the gloss of the paint film surface is caused by the formation of minute unevenness on the surface of the dried paint film, which results in diffuse reflection of the incident light. To achieve strong diffuse reflection in the paint film, three conditions need to be met simultaneously. First, the wet paint film contains a sufficient amount of matting agents with appropriate particle sizes. Second, volume shrinkage occurs during the drying or curing process of the paint film. Third, the matting agents can migrate appropriately to the surface of the paint film. Since UV coatings have a high solid content, high crosslinking density, and fast curing speed, the matting powder does not have enough time to float to the surface of the paint film during construction and curing, making it difficult to achieve matting; especially for fully solid UV coatings, during the process of the paint liquid becoming a paint film during construction and curing, since there is no dissolution and volatilization, the volume hardly shrinks or shrinks very little, and it is difficult to form an uneven paint film microscopically, increasing the difficulty of matting for UV coatings. Matting UV coatings have always been the focus and difficulty for engineers to develop. No matter how the construction process is adjusted for the commonly used solvent-based spray UV paints, vacuum spray UV paints, curtain coating UV paints, and roller coating UV paints (single roller, positive and reverse roller, and laser roller) in the market, the gloss cannot be reduced below 8 degrees. Because adding an excessive amount of matting powder will not only affect the leveling property of the paint film, resulting in defects such as orange peel in the paint film, but also affect the stability of the paint construction cycle. To achieve a zero-gloss effect, currently, UV coating engineers have developed two special process paints. One is the roller coating and film pressing UV coating process. The other is the UV paint excimer process. The UV coatings of the above two processes have certain limitations. For the film pressing UV coating, in addition to the normal roller coating construction, it also requires an additional process of film pressing - UV curing - film peeling. The key is that an additional UV film press is needed to implement the film pressing process. At the same time, this process will increase the production consumption of PE matting film and also increase the energy consumption during the semi-curing of the film press by UV. It will increase the unit product cost and the equipment investment cost. For the UV excimer process, an additional excimer curing machine is required. The current market price of the excimer curing machine is around 1 million yuan, which requires a large amount of capital investment. Even most of them use the nitrogen protection excimer curing process, which also consumes nitrogen and requires the manufacturer to have the operation qualification for high-pressure equipment.

[0004] Currently, due to inappropriate selection of wetting and dispersing agents, inappropriate dosage of matting powder, and inappropriate use of main resins and reactive monomers in the traditional method for producing matting paint films, it is very difficult to form a standard with a gloss of 4 degrees or less (a gloss of less than 5 degrees is zero gloss). And during the production process, an increase in viscosity and thixotropy during the roller coating cycle of the paint will lead to defective problems such as rough board surfaces. The UV film pressing construction continuously consumes PE matting film and uses electrical energy for semi-curing of UV, resulting in high production costs. The parts of the excimer curing equipment, such as the low-pressure mercury lamp tubes, have a high failure rate, the construction stability is poor, and nitrogen protection curing is required, with high production qualification requirements. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a fully solid zero-spectroscopic UV roller-coated clear topcoat, which has the advantages of stable and consistent zero-spectroscopic effect of the paint film, simplified production, energy saving and low cost, and solves the problems that it is difficult to form zero-spectroscopy in the traditional production process, high production cost and poor quality stability.

[0006] To achieve the purpose of stable and consistent zero-spectroscopic effect of the paint film and simplified production, energy saving and low cost, the present invention provides the following technical solutions: a fully solid zero-spectroscopic UV roller-coated clear topcoat, and the mass percentage of the formula of the fully solid zero-spectroscopic UV roller-coated clear topcoat is as follows:

[0007]

[0008]

[0009] Preferably, the production of the fully solid zero-spectroscopic UV roller-coated clear topcoat requires adjusting the viscosity and thickness of the paint liquid raw materials through a roller coater, and the coating amount of the roller coater is maintained at 20-25 g / m 2 .

[0010] Through the above technical solutions, by adjusting the viscosity and thickness of the paint liquid raw materials through a roller coater, it is ensured that the surface of the coating is uniform and free of bubbles, and the raw material loss is small.

[0011] Preferably, the bifunctional polyurethane acrylate resin is in a transparent and viscous form, and the storage temperature of the bifunctional polyurethane acrylate resin and the hexafunctional polyurethane acrylate resin needs to be maintained between 15-25 °C.

[0012] Through the above technical solutions, the bifunctional polyurethane acrylate resin plays a film-forming role, which has good yellowing resistance and curing speed, and has easy matting property. Under the same dosage of matting powder, the film gloss of the paint film added with the bifunctional polyurethane acrylate resin is 30% lower than that of the paint film made of other resins, effectively improving the matting property of the matting powder. The hexafunctional polyurethane acrylate resin can increase the crosslinking density of the paint, improve the hardness of the paint, improve the scratch resistance of the paint, and at the same time is beneficial to the paint film to overcome oxygen inhibition polymerization and improve the surface dryness of the paint film. The cured adhesive has high wear resistance, adhesion, flexibility, high peel strength and excellent low temperature resistance.

[0013] Preferably, the molecular structure of the special reactive monomer has a hydrophilic group and a hydrophobic group. When the paint liquid raw material is in a microgel and has not been completely cured into a film, the special reactive monomer forms an uneven paint film on the surface of the coating film.

[0014] Through the above technical solution, by using a special reactive monomer with amphiphilic and polymerizable properties, and by taking advantage of the poor compatibility of the paint liquid raw materials in the microgel state before they are completely cured into a film, when the paint liquid raw materials form microgels, a slightly convex and uneven paint film is formed on the surface of the coating film, generating a matting function similar to matting powder. The hydrophilic and hydrophobic groups in the molecular structure of the special reactive monomer ensure that the gloss of the cured paint film reaches zero gloss.

[0015] Preferably, the DPHA monomer is a hexa-functional monomer, and both the HDDA monomer and the TPGDA monomer are bi-functional monomers.

[0016] Through the above technical solution, by using the DPHA monomer with the property of a hexa-functional monomer, which contains six double bonds that can participate in the polymerization reaction in its molecule, it has a high curing speed and hardness, balances the paint viscosity, improves the paint hardness and scratch resistance. For the HDDA monomer and the TPGDA monomer with the property of bi-functional monomers, each molecule contains two active groups that can participate in the photocuring reaction, crosslinking reactions occur faster, and they have extremely strong diluting ability. At the same time, they have a very high molar double bond content, which can not only adjust the paint viscosity but also improve the scratch resistance of the paint film.

[0017] Preferably, the 184 photoinitiator is a white crystalline powder, and the light transmittance of the 184 photoinitiator at the light wavelengths of 425 nm and 500 nm should be greater than 98%.

[0018] Through the above technical solution, the 184 photoinitiator plays an initiating role, has good yellowing resistance, and can better balance the surface drying and inner drying of the paint, without having a negative impact on the low gloss of the paint film.

[0019] Preferably, the MBF photoinitiator is a colorless liquid, and the MBF photoinitiator should be added when the temperature of the paint liquid raw materials is maintained above 17°C.

[0020] Through the above technical solution, by controlling the temperature of the paint liquid raw materials above 17°C and adding the MBF photoinitiator, it is ensured that the MBF photoinitiator is completely melted and evenly dispersed in the paint, thereby optimizing the polymerization reaction. And compared with other cleavage-type photoinitiators, the MBF photoinitiator has better surface drying property.

[0021] Preferably, the HLB value of the wetting and dispersing agent is maintained between 15 and 18, and the particle diameter of the wetting and dispersing agent should be less than 0.5 mm.

[0022] Through the above technical solution, by controlling the HLB value of the wetting and dispersing agent, the wetting and dispersing effects of the paint liquid raw materials are directly affected. Using the wetting and dispersing agent in the UV topcoat with a high content of matte powder can significantly reduce the thixotropy of the paint, stabilize the paint viscosity, and properly match the dosage to ensure the hydrophilic-lipophilic balance value of the paint liquid. During the roller coating cycle construction process, the paint liquid viscosity does not increase and the thixotropy phenomenon does not occur. At the same time, controlling the diameter range of the solid particles in the wetting and dispersing agent ensures the uniform distribution of particles, paint spots, and line pockmarks on the film surface, improving the flatness and aesthetics of the coating surface, as well as the quality and performance of the paint film.

[0023] Preferably, under the condition that the operator wears protective equipment, the defoamer, leveling agent, and matte powder are added to the paint liquid raw materials.

[0024] Through the above technical solution, the defoamer plays a defoaming role, the leveling agent plays a leveling role, improving the smoothness and anti-cratering property of the paint film, and the matte powder plays a matting role. The property of low oil absorption is not likely to affect the paint viscosity. Wearing protective equipment protects the safety and hygiene of the operator, such as gloves, masks, goggles, etc. Because these additives such as defoamers, leveling agents, and matte powders are all chemical substances, direct contact with the skin or inhalation into the body may cause harm to human health. At the same time, it is also necessary to avoid the paint liquid raw materials splashing into the eyes or mouth during the production process to avoid allergic reactions, skin ulcers and other adverse reactions.

[0025] Preferably, the overall viscosity standard of the paint liquid raw materials is maintained at 800±100 mPa·s / 25°C, and the curing energy requirement during construction is greater than 600 millijoules per square centimeter.

[0026] Through the above technical solution, the zero-gloss full-matte effect can be achieved by conventional production equipment, which can save equipment investment, simplify the production process, save production site, reduce energy consumption, improve production efficiency, and reduce unit production cost for paint manufacturers. Setting the curing energy controls the curing speed and final performance of the coating, and can improve product quality and ensure the stable and consistent zero-gloss effect of the paint film.

[0027] Compared with the prior art, the present invention provides a fully solid-content zero-gloss UV roller coating clear topcoat, which has the following beneficial effects:

[0028] 1. The invention uses bifunctional polyurethane acrylate resin to form a film, reducing the gloss of the traditional process paint film by 30%. The hexa-functional polyurethane acrylate resin helps to improve the crosslinking density of the paint, enhance the hardness of the paint, and improve the scratch resistance of the paint. A special reactive monomer with amphiphilic and polymerizable properties is used. Taking advantage of the poor compatibility of the paint liquid raw materials in the same system when they are in the microgel state and have not been completely cured into a film, when the paint liquid raw materials form microgels, a slightly convex and concave paint film is formed on the surface of the coating film, generating a matting function similar to matting powder. The hydrophilic and hydrophobic groups in the molecular structure of the special reactive monomer ensure that the gloss of the paint film reaches zero gloss after curing. Adding DPHA monomer with hexa-functional groups, HDDA monomer and TPGDA monomer with bifunctional groups accelerates the crosslinking reaction. In combination with 184 photoinitiator and MBF photoinitiator, the surface dryness and inner dryness of the paint are optimized and balanced. By controlling the HLB value and particle diameter of the wetting and dispersing agent, the viscosity of the paint liquid raw materials does not increase during the roller coating cycle construction process, and no thixotropy phenomenon occurs. With the cooperation of defoaming agent for defoaming and leveling agent for leveling, the smoothness and anti-cratering properties of the paint film are improved. The matting powder stabilizes the paint viscosity, achieving the beneficial effect of stable and consistent zero gloss effect of the paint film.

[0029] 2. The invention uses bifunctional polyurethane acrylate resin, special reactive monomer and wetting and dispersing agent to assist the matting powder to improve the matting property, making the gloss of the paint film lower than 4 degrees, breaking through the technical barrier that the traditional UV paint ordinary construction and curing process cannot achieve a full-matt effect (zero gloss). Without adding equipment and processes, a full-solid content zero-gloss UV roller coating clear topcoat is produced through a conventional roller coating machine equipment, meeting the market's required full-matt effect, saving equipment investment, simplifying the production process, saving production site, reducing energy consumption, improving production efficiency, and reducing unit production cost, achieving the beneficial effect of simplified production, energy saving and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a comparison table of the advantages of the present invention and special process UV paint. DETAILED DESCRIPTION OF THE INVENTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figure 1 , a full-solid content zero-gloss UV roller coating clear topcoat, and the mass percentage of the formula of the full-solid content zero-gloss UV roller coating clear topcoat is as follows:

[0033] Bifunctional polyurethane acrylate resin: 10 - 50%

[0034] Hexafunctional polyurethane acrylate resin: 5 - 20%

[0035] The bifunctional polyurethane acrylate resin is in emulsion form, specifically a bifunctional polyurethane acrylate resin with the brand LT6121F produced by Changsha Guangxin New Materials Technology Co., Ltd. The storage temperature of the bifunctional polyurethane acrylate resin and the hexafunctional polyurethane acrylate resin needs to be maintained between 15 - 25°C. The bifunctional polyurethane acrylate resin plays a film-forming role, has good yellowing resistance and curing speed, and has easy matting property. Under the same dosage of matting powder, the film gloss of the paint film added with the bifunctional polyurethane acrylate resin is 30% lower than that of the paint film made of other resins, effectively improving the matting property of the matting powder. The hexafunctional polyurethane acrylate resin can increase the crosslinking density of the paint, improve the hardness of the paint, and improve the scratch resistance of the paint. At the same time, it is beneficial for the paint film to overcome oxygen inhibition polymerization and improve the surface dryness of the paint film. The cured adhesive has high wear resistance, adhesion, flexibility, high peel strength, and excellent low-temperature performance.

[0036] Special reactive monomer: 5 - 10%

[0037] The molecular structure of the special reactive monomer has hydrophilic and hydrophobic groups, specifically octadecyl to docosyl acrylate (BEA) with the brand EM258A produced by Changxing Chemical Industry (China) Co., Ltd. When the paint liquid raw material is in a microgel state and has not been completely cured into a film, the special reactive monomer forms an uneven paint film on the surface of the coating film. The special reactive monomer with amphiphilic and polymerizable characteristics, combined with the poor compatibility of the same system when the paint liquid raw material is in a microgel state and has not been completely cured into a film, forms a small convex and concave uneven paint film on the surface of the coating film while the paint liquid raw material forms a microgel, generating a matting function similar to that of matting powder. The hydrophilic and hydrophobic groups in the molecular structure of the special reactive monomer ensure that the gloss of the paint film reaches zero gloss after curing.

[0038] DPHA monomer: 3 - 10%

[0039] HDDA monomer: 20 - 50%

[0040] The DPHA monomer is a hexafunctional monomer, containing six double bonds that can participate in polymerization reactions in the molecule, having a relatively high curing speed and hardness, balancing the paint viscosity, improving the hardness and scratch resistance of the paint. Both the HDDA monomer and the TPGDA monomer are bifunctional monomers, each containing two active groups that can participate in photocuring reactions in the molecule, crosslinking faster, having extremely strong diluting ability, and at the same time having a high molar double bond content, which can not only adjust the paint viscosity but also improve the scratch resistance of the paint film.

[0041] 184 photoinitiator 3 - 7%

[0042] The 184 photoinitiator is a white crystalline powder. The light transmittance of the 184 photoinitiator at the light wavelengths of 425nm and 500nm should be greater than 98%. It plays an initiating role through the 184 photoinitiator, has good yellowing resistance, and can better balance the surface drying and inner drying of the paint, and will not have a negative impact on the low gloss of the paint film.

[0043] MBF photoinitiator 0.5 - 2%

[0044] The MBF photoinitiator is a colorless liquid. When the temperature of the paint liquid raw material is maintained above 17°C, the MBF photoinitiator is added to ensure that the MBF photoinitiator is completely melted and evenly dispersed in the paint material, thereby optimizing the polymerization reaction. And compared with other cleavage-type initiators, the MBF photoinitiator has better surface drying property.

[0045] Wetting and dispersing agent 0.5 - 4%

[0046] The HLB value of the wetting and dispersing agent is maintained between 15 - 18. Specifically, it is a kind of alkaline pigmentophilic group polymer compound with the brand number Y3600 produced by Kaiping Zicai Chemical Co., Ltd., and the amine value is 12. The particle diameter of the wetting and dispersing agent should be less than 0.5mm. Controlling the HLB value of the wetting and dispersing agent directly affects the wetting and dispersing effects of the paint liquid raw material. Using the wetting and dispersing agent in the UV topcoat with a high content of matte powder can significantly reduce the thixotropy of the paint, stabilize the paint viscosity, and properly match the dosage to ensure the hydrophilic-lipophilic balance value of the paint liquid. During the roller coating cycle construction process, the paint liquid viscosity does not increase and no thixotropy phenomenon occurs. At the same time, controlling the range of the solid particle diameter in the wetting and dispersing agent ensures the uniform distribution of the particles, paint spots, and line pockmarks on the paint film surface, improving the flatness and aesthetics of the coating surface, as well as the quality and performance of the paint film.

[0047] Defoaming agent 0.1 - 0.3%

[0048] Leveling agent 20 - 30%

[0049] Matte powder 10 - 20%

[0050] When the operator is in a state of wearing protective equipment, defoamer, leveling agent and matte powder are added into the paint liquid raw material. The defoamer plays a defoaming role, the leveling agent plays a leveling role, improving the smoothness and anti-cratering property of the paint film, and the matte powder plays a matting role. The property of low oil absorption is not easy to affect the paint viscosity. Wearing protective equipment protects the safety and hygiene of the operator, such as gloves, masks, goggles, etc. Because these additives such as defoamer, leveling agent and matte powder are all chemical substances, if directly contacting the skin or inhaled into the body, they may cause harm to human health. At the same time, it is also necessary to avoid the paint liquid raw material splashing into the eyes or mouth during the production process to avoid adverse reactions such as allergies and skin ulcers.

[0051] 5 - 10% of TPGDA monomer

[0052] For the production of zero-gloss UV roller coating clear topcoat, the viscosity and thickness of the paint liquid raw material need to be adjusted by a roller coater. The coating amount of the roller coater is maintained at 20 - 25 g / m 2 , ensuring that the surface of the coating is uniform without bubbles and the raw material loss is small.

[0053] The overall viscosity standard of the paint liquid raw material is maintained at 800 ± 100 mPa.s / 25℃, and the curing energy requirement during construction is greater than 600 millijoules per square centimeter. The zero-gloss full-matte effect can be achieved through conventional production equipment, which can save equipment investment, simplify the production process, save production site, reduce energy consumption, improve production efficiency, and reduce unit production cost for paint using manufacturers. Setting the curing energy controls the curing speed and final performance of the coating, which can improve product quality and ensure the stable and consistent zero-gloss effect of the paint film.

[0054] Example 1

[0055] Prepare zero-gloss UV roller coating clear topcoat according to the formula raw materials of the present invention, and the experimental data are as follows:

[0056]

[0057]

[0058] Among them, the proportion of the leveling agent is 0.2 kg, which is less, so the production time of the roller coater equipment needs to be appropriately extended.

[0059] Example 2

[0060] Prepare zero-gloss UV roller coating clear topcoat according to the formula raw materials of the present invention, and the experimental data are as follows:

[0061] Bifunctional polyurethane acrylate resin 26 kg Hexafunctional polyurethane acrylate resin 5 kg Special reactive monomer 5 kg DPHA monomer 7 kg HDDA monomer 30 kg 184 photoinitiator 3.5 kg MBF photoinitiator 1 kg Wetting and dispersing agent 3 kg Defoamer 0.1 kg Leveling agent 0.2 kg Matting powder 14 kg TPGDA monomer 5.2 kg

[0062] Among them, the proportion of the HDDA monomer is 30 kg, which is more, suitable for the preparation process of dark color UV roller coating clear topcoat, and the matte effect is more beautiful.

[0063] Example 3

[0064] Prepare a fully solid content zero - splitting UV roller - coating clear topcoat according to the formula raw materials of the present invention. The experimental data are as follows:

[0065] Bifunctional polyurethane acrylate resin 21 kg Hexafunctional polyurethane acrylate resin 6 kg Special reactive monomer 6 kg DPHA monomer 9 kg HDDA monomer 22 kg 184 photoinitiator 3.7 kg MBF photoinitiator 1 kg Wetting and dispersing agent 1 kg Defoamer 0.3 kg Leveling agent 10 kg Matting powder 15 kg TPGDA monomer 5 kg

[0066] Among them, when the leveling agent ratio is configured with 10 kg in a relatively large amount, the production time of the roller - coating machine equipment needs to be appropriately shortened, and the production efficiency is higher, which is suitable for the production of high - transparency zero - splitting UV roller - coating clear topcoats.

[0067] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fully solid zero-dispersion UV roller-coated clear topcoat, characterized in that: The mass percentages of the formulation of the all-solid zero-spectroscopic UV roller-coated clear topcoat are as follows: Bifunctional polyurethane acrylate resin: 10 - 50% Hexafunctional polyurethane acrylate resin: 5 - 20% Special reactive monomer: 5 - 10% DPHA monomer: 3 - 10% HDDA monomer: 20 - 50% 184 photoinitiator: 3 - 7% MBF photoinitiator: 0.5 - 2% Wetting and dispersing agent: 0.5 - 4% Defoaming agent: 0.1 - 0.3% Leveling agent: 20 - 30% Matting powder: 10 - 20% TPGDA monomer: 5 - 10%, The special reactive monomer is octadecyl to docosyl acrylate with the trade name EM258A produced by Changxing Chemical Industry (China) Co., Ltd.

2. The all-solid zero-dispersion UV roller coating clear topcoat according to claim 1, wherein: The production of the all-solid zero-spectroscopic UV roller-coated clear topcoat requires adjusting the viscosity and thickness of the paint liquid raw materials through a roller coater, and the coating amount of the roller coater is maintained at 20 - 25 g / m².

3. A fully solid zero-dispersion UV roller coating clear topcoat according to claim 1, characterized in that: The bifunctional polyurethane acrylate resin is in the form of an emulsion, and the storage temperature of the bifunctional polyurethane acrylate resin and the hexafunctional polyurethane acrylate resin needs to be maintained between 15 - 25°C.

4. A fully solid zero-dispersion UV roller coating clear topcoat according to claim 2, characterized in that: The defoaming agent, leveling agent, and matting powder should be added to the paint liquid raw materials when the operator is wearing protective equipment.

5. A fully solid zero-dispersion UV roller coating clear topcoat according to claim 2, characterized in that: The overall viscosity standard of the paint liquid raw materials is maintained at 800 ± 100·mPa.s / 25°C, and the curing energy requirement during construction is greater than 600 millijoules per square centimeter.

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