Water-based wear-resistant high-brightness release agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of printing, in particular to the field of C09D175, and more particularly relates to a water-based wear-resistant high-brightness release agent as well as a preparation method and application thereof. The water-based wear-resistant high-brightness release agent is prepared from the following raw materials: water-based acrylic resin, water-based polyurethane, wax emulsion, deionized water, a cosolvent and the like. The water-based acrylic resin is mainly used and matched with the water-based polyurethane and the wax emulsion, the prepared release agent is coated on the PET base film to prepare the hot stamping film release layer, and the effects of good slitting property, good wear resistance and high brightness can be achieved during hot stamping or cold stamping; meanwhile, the product is a water-based system and does not contain non-environment-friendly organic solvents such as methylbenzene, so that the use and storage safety performance is effectively improved, and the emission of organic volatile substances is also reduced.

Description

Technical Field

[0001] The present invention relates to the field of printing technology, in particular to the field of C09D175, and more specifically to a water-based wear-resistant high-brightness release agent and a preparation method and application thereof. Background Art

[0002] Traditional hot stamping film release agents often have problems such as poor wear resistance and insufficient brightness, which affect or limit the appearance and service life of hot stamping products, and are not well used in some places with high requirements for brightness and wear resistance. With the continuous advancement of science and technology, people have higher and higher requirements for the comprehensive performance of hot stamping products, and at the same time, environmentally friendly waste-free coating processes have received more and more attention and development. Therefore, the development of an environmentally friendly release agent with both wear resistance and high brightness has become an urgent need in the industry.

[0003] Patent CN 111332057 A discloses a process for producing electrochemical aluminum. The raw materials for preparing the release layer involved in the process include: 2 parts of wax emulsion, 2 parts of modified oxidized polymer wax, 1 part of aqueous adhesion promoter, 20 parts of ethanol, 30 parts of deionized water, 0.5 parts of defoaming agent, 0.5 parts of dispersant, and 0.5 parts of leveling agent. Since the raw materials for preparing the release layer include wax emulsion and modified oxidized polymer wax, the transparency is relatively low. Patent CN 114031983 A discloses a silk-screen cold stamping film coating and its preparation process. The raw materials for preparing the silk-screen cold stamping film coating include a release layer. The raw materials for preparing the release layer include aqueous cellulose resin and aqueous acrylic resin. However, the wear resistance of the release layer is relatively low, and the product is not wear-resistant, which affects the application range of the product.

[0004] Therefore, there is an urgent need for a release agent that is wear-resistant, has good light transmittance and is removable to meet the usage requirements of different industrial scenarios. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a water-based wear-resistant high-brightness release agent, the preparation raw materials of which include: water-based acrylic resin, water-based polyurethane resin, wax emulsion, deionized water, co-solvent, pH value adjuster, etc.

[0006] Preferably, the water-based wear-resistant and high-brightness release agent comprises, by weight: 0.6-1 parts of water-based acrylic resin, 5.4-6.8 parts of water-based polyurethane, 1-1.5 parts of wax emulsion, 40-55 parts of deionized water, and 30-35 parts of co-solvent.

[0007] Preferably, the waterborne acrylic resin has a glass transition temperature (Tg) of 100-160° C., a weight average molecular weight of 6000-15000, and an acid value of 150-250 mg KOH / g.

[0008] The present invention selects a water-based acrylic resin with a glass transition temperature of 100-160°C, a weight average molecular weight of 6000-15000, and an acid value of 150-250 mg KOH / g. This solid water-based acrylic resin has good separation and transfer performance and high brightness; it can be effectively dissolved in water without a co-solvent in an alkaline solution. The resin itself is a high molecular weight hard resin, which can provide a coating with high gloss, high hardness and scratch resistance after coating. At the same time, this acrylic resin has good compatibility; on the other hand, the water-based acrylic resin is different from the traditional acrylic emulsion. Its solution is colorless and transparent, and the coating effect has a good glossiness, while the emulsion is white and opaque, and has a tendency to be foggy and matte after coating. However, the pH value of the system needs to be controlled within the weak alkaline range of 8-9. When the pH value is too low, the resin tends to precipitate and the system is unstable; when the pH value is too high, the coating may corrode the coating roller. The solid water-based acrylic resin in the present invention is preferably one or more of Hanwha water-based GA1700, water-based acrylic resin copolymer GA1900, NeoCryl B817 water-based acrylic copolymer, Hanwha water-based acrylic resin S70, S80, S90.

[0009] Preferably, the waterborne polyurethane is waterborne anionic polyurethane and / or waterborne cationic polyurethane.

[0010] More preferably, the waterborne polyurethane resin is waterborne anionic polyurethane.

[0011] More preferably, the elongation at break of the aqueous anionic polyurethane is 30-150%.

[0012] The present invention selects an aqueous anionic polyurethane with a breaking elongation of 30-150%, which has good detachability and is easy to peel off; at the same time, the use of such polyurethane can interact with the aqueous acrylic resin to improve the cohesive energy of the release agent, and react with the added crosslinking agent aziridine during coating to provide the release layer with good solvent resistance and scratch resistance. The aqueous polyurethane in the present invention is preferably selected from one or more of ADM-1319, ADM-2388, ADM-1252, ADM-2133, ADM-1728, and Green Protection Polyurethane PT-575G.

[0013] Preferably, the wax emulsion has a pH value of 7-9, a solid content of 20-45 wt%, and a softening point of 80-140° C. As an implementable case, the wax emulsion includes one or more of montan wax, palm wax, oxidized polyethylene wax, and polyethylene wax.

[0014] The present invention selects a wax emulsion with specific parameters, so that the release agent has better anti-adhesion, anti-scratch, anti-fouling and friction resistance properties, and also makes the coating of the release agent smoother and softer and improves the hydrophobicity and sealing properties.

[0015] Preferably, the solvent includes one of methanol, ethanol, ethylene glycol, dipropylene glycol propyl ether, dipropylene glycol dimethyl ether, isopropanol, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, butanone, and acetone.

[0016] The raw materials for preparing the release agent in the present invention also include a dispersant, a preservative and a pH regulator.

[0017] Preferably, the above-mentioned comprises AMP-95, AMP-90, triethylamine or ammonia water, wherein the mass concentration of ammonia water is 18-25%.

[0018] Preferably, the dispersant includes one of BYK-2150, BYK-935W, BYK-2190, BYK-9077, and BYK-9076.

[0019] The present invention does not further limit the preservative, and any auxiliary agent that can improve the antiseptic and antibacterial properties of the release agent may be used, including but not limited to Wink BIT-20 preservative.

[0020] The second aspect of the present invention provides a method for preparing a water-based wear-resistant high-brightness release agent, comprising the following steps:

[0021] S1. Adjust the system to be weakly alkaline with deionized water, add water-based acrylic resin to dissolve, and prepare a water-based acrylic resin solution;

[0022] S2, mixing the waterborne polyurethane resin and the wax emulsion, adding deionized water and a solvent, and then adjusting the system to be weakly alkaline to prepare a waterborne polyurethane solution;

[0023] S3. Evenly stir and mix the aqueous polyurethane solution, aqueous acrylic resin solution, dispersant and preservative, and then adjust the system to be weakly alkaline to obtain an aqueous wear-resistant and high-brightness release agent.

[0024] A third aspect of the present invention provides an application of a water-based wear-resistant and high-brightness release agent, which is applied in the field of hot stamping and cold stamping films.

[0025] Beneficial Effects

[0026] (i) The present invention mainly uses water-based acrylic resin, and is combined with water-based polyurethane and wax emulsion. The release agent prepared by this combination is coated on the PET base film to prepare a hot stamping film release layer, which can achieve good wear resistance and high brightness when hot stamping cloth or paper.

[0027] (ii) The release agent prepared by the present invention uses deionized water and ethanol as solvents to obtain a release agent of an aqueous solvent system, which does not include toxic volatile organic solvents such as toluene, and the product is greener, safer and more environmentally friendly.

[0028] (III) Compared with the common release agents on the market, the aqueous acrylic resin used in the present invention has an acid value of 180-250 mg KOH / g, which can give the release agent coating a higher brightness, and the weight average molecular weight of 6000-12000 also makes the release agent coating have a certain hardness.

[0029] (IV) At the same time, the present invention selects an aqueous anionic polyurethane with a breaking elongation of 30%-150%, which can improve the strippability of the release agent coating, and the aqueous anionic polyurethane and aqueous acrylic resin are compounded and cross-linked with each other to improve the scratch resistance of the coating.

[0030] (V) In the process of preparing the wear-resistant and high-brightness release agent, the pH value of each step system needs to be strictly controlled to be weakly alkaline, especially when the pH value is in the range of 8 to 9, so as to ensure that the water-based acrylic resin has better stability and is not easy to precipitate. When the pH value is too low, the resin tends to precipitate and the system is unstable; when the pH value is too high, the coating may corrode the coating roller.

[0031] (VI) The solid content of this product is 2.5-5.5wt%, and the pH value is 8-9; at the same time, compared with the traditional water-based release agent emulsion, it has better appearance transparency and a wider range of applications. DETAILED DESCRIPTION

[0032] Example 1

[0033] The first aspect of this example provides a water-based wear-resistant and high-brightness release agent, the raw materials for its preparation are calculated by weight as follows: 0.6 parts of water-based acrylic resin, 6.8 parts of water-based anionic polyurethane, 1.4 parts of wax emulsion, 2.7 parts of pH adjuster, 45.6 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0034] The waterborne acrylic resin has a Tg (glass transition temperature) of 120° C., a weight average molecular weight of 7000, an acid value of 218 mg KOH / g, a model of SR70, and is purchased from Hanwha.

[0035] The breaking elongation of the water-based anionic polyurethane is 30-150%, and the model is ADM-1319.

[0036] The wax emulsion is montan wax with a pH value of 7-8, a solid content of 20-22wt%, and a softening point of 80-110°C, and the model is EWAXM-920 produced by Guangzhou Mingshen New Materials.

[0037] The dispersant is BYK-935W from BYK Chemical.

[0038] The preservative is Wink BIT-20 preservative.

[0039] The pH value regulator is ammonia water with a mass concentration of 25%.

[0040] The second aspect of this example provides a method for preparing a water-based wear-resistant high-brightness release agent, which comprises the following steps:

[0041] S1, dissolving 0.6 parts of water-based acrylic resin in 1.2 parts of deionized water solvent, and then adding 0.2 parts of pH adjuster to adjust the system to pH = 8-9, to prepare a water-based acrylic resin solution;

[0042] S2, 6.8 parts of waterborne polyurethane resin and 1.4 parts of wax emulsion are mixed, and then 44.4 parts of deionized water and 52.2 parts of ethanol are added, and then 2.2 parts of pH regulator are added to adjust the system to pH = 8-9 to prepare a waterborne polyurethane solution;

[0043] S3. Stir and mix the aqueous polyurethane solution, aqueous acrylic resin solution, 0.1 part of dispersant and 0.1 part of preservative evenly, and then add the remaining amount of pH adjuster to adjust the system to pH=8-9, so as to obtain an aqueous wear-resistant and high-brightness release agent.

[0044] The third aspect of this example provides an application of a water-based wear-resistant and high-brightness release agent, which is applied in the field of hot stamping films.

[0045] Performance Evaluation

[0046] Test object: the release agent prepared in Example 1.

[0047] Before being put on the machine, aziridine crosslinking agent (CAS: 64265-57-2) is added to the release agent, and the crosslinking agent is 0.3% of the mass of the release agent, and then coated.

[0048] The release agent of the present invention is used in the same process as the traditional hot stamping film release agent. After being shaken evenly, it is directly coated on the surface of the non-corona PET base film, with a coating dry weight of 0.2-0.4g / m 2 , and then rolled up after hot air drying for 10-15 seconds, and the oven temperature is controlled at 150℃.

[0049] By using the release agent of the present invention, the coating film surface is uniform, transparent and dense, the hot stamping release property is excellent, the peeling force is 5-10gf / 25mm, the brightness is 85-88GU (60°, brightness meter), and the wear resistance is 90-95% (detected by a friction tester with a reflection densitometer); the requirements of wear resistance, high brightness and peelability of hot stamping cloth and paper can be met.

[0050] Example 2

[0051] The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparation are calculated by weight as follows: 0.6 parts of water-based acrylic resin, 6.8 parts of water-based anionic polyurethane, 1.4 parts of wax emulsion, 1.5 parts of pH adjuster, 46.8 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0052] The mixed liquid has poor transparency, a pH value of 7-8, and precipitates after being left for a period of time.

[0053] Example 3

[0054] The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparation are calculated by weight as follows: 0.6 parts of water-based acrylic resin, 6.8 parts of water-based anionic polyurethane, 1.4 parts of wax emulsion, 2.7 parts of pH adjuster, 45.6 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0055] The elongation at break of the waterborne polyurethane resin used is 250% (purchased from Germany Opeldi, model: U9800). The release test after coating shows a peeling force of 1-3g f / 25mm, which is relatively small and has poor slitting properties.

[0056] Example 4

[0057] The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparation are calculated by weight as follows: 1.8 parts of water-based acrylic resin, 4.8 parts of water-based anionic polyurethane, 1.4 parts of wax emulsion, 2.7 parts of pH adjuster, 45.6 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0058] The peeling force of the release test after coating is 10-15g f / 25mm, mainly because the acrylic acid value ratio is too high, the polyurethane resin ratio is too low, the peeling is tight, which affects the peeling speed;

[0059] Example 5

[0060] The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparation are calculated by weight as follows: 0.6 parts of water-based acrylic resin, 7 parts of water-based anionic polyurethane, 1 part of wax emulsion, 2.7 parts of pH adjuster, 45.6 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0061] The friction resistance of the release test after coating is 85%. Due to the low ratio of water-based acrylic resin and wax emulsion, the wear resistance is poor.

[0062] Example 6

[0063] The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparation are calculated by weight as follows: 1 part of aqueous acrylic resin, 5.5 parts of aqueous anionic polyurethane, 2 parts of wax emulsion, 2.7 parts of pH adjuster, 45.6 parts of deionized water, 52.2 parts of ethanol, 0.1 parts of dispersant, and 0.1 parts of preservative.

[0064] The release gloss after coating is 80GU, and the peeling force is 10-15gf / 25mm. This is mainly because the high proportion of wax emulsion affects the glossiness and causes the peeling force to be large.

Claims

1. A water-based wear-resistant high-brightness release agent, characterized in that: The invention comprises the following raw materials: water-based acrylic resin, water-based polyurethane, wax emulsion, deionized water, cosolvent, pH value adjuster, cross-linking agent and the like.

2. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The raw materials include, by weight: 0.6-1 parts of water-based acrylic resin, 5.4-6.8 parts of water-based polyurethane, 1-1.5 parts of wax emulsion, 40-55 parts of deionized water, and 30-35 parts of cosolvent.

3. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The water-based acrylic resin has a glass transition temperature of 100-160° C., a weight average molecular weight of 6000-15000, and an acid value of 150-250 mg KOH / g.

4. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The waterborne polyurethane is waterborne anionic polyurethane.

5. The water-based wear-resistant and high-brightness release agent according to claim 4, characterized in that: The breaking elongation of the aqueous anionic polyurethane is 30-150%.

6. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The wax emulsion has a pH value of 7-9, a solid content of 20-45 wt % and a softening point of 80-140° C.

7. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The co-solvent comprises one or more of methanol, ethanol, ethylene glycol, propylene glycol methyl ether, dipropylene glycol propyl ether, dipropylene glycol dimethyl ether, isopropanol, ethylene glycol monoethyl ether and acetone.

8. The water-based wear-resistant and high-brightness release agent according to claim 1, characterized in that: The pH regulator includes one or more of alkanolamine, dimethylamine and ammonia water.

9. A method for preparing the water-based wear-resistant and high-brightness release agent according to any one of claims 1 to 8, characterized in that: The steps include: S1, adding water-based acrylic resin into deionized water adjusted to weak alkalinity with a pH adjuster in advance to dissolve it, to prepare an acrylic resin aqueous solution; S2, mixing the waterborne polyurethane resin and the wax emulsion, adding deionized water and a cosolvent, and adding a pH regulator to adjust the system to be weakly alkaline to prepare a waterborne polyurethane wax emulsion mixed solution; S3, stirring and mixing the aqueous polyurethane wax emulsion solution and the aqueous acrylic resin solution to obtain an aqueous wear-resistant and high-brightness release agent.

10. An application of the water-based wear-resistant and high-brightness release agent according to any one of claims 1 to 8, characterized in that: Used in the production of hot stamping and cold stamping films.