A method for preparing a slip-resistant coating with elastic self-repairing function by a combined curing method

Abstract

This invention relates to a method for preparing a slip-resistant coating with elastic self-healing function using a combined curing method. Specifically, the method of this invention uses a specific type of UV release resin in combination with a combined curing method to prepare a coating that combines excellent slip properties, wear resistance, and elastic self-healing function.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically to a method for preparing a slip-resistant coating with elastic self-healing function using a combined curing method. Background Technology

[0002] With the rise of mobile games in recent years, mobile phones are being used more and more frequently, resulting in shorter screen lifespans and increased susceptibility to scratches, blurring, and increased friction, significantly reducing the gaming experience. This places higher demands on the smoothness and durability of screen protectors. However, ordinary screen protectors on the market often offer a noticeably rough and unresponsive feel, failing to meet the demands of high-frequency scrolling during mobile gaming.

[0003] High-functionality UV-cured coatings can easily produce dense UV-cured coatings with good slip properties and abrasion resistance. These properties can be further improved by adding nanoparticle dispersions. However, dense UV-cured coatings are brittle and cannot be bent, making them unsuitable for protecting mobile phones with now-common flexible curved screens.

[0004] Currently, the main technical means used to improve the slip properties of thermosetting coatings are as follows:

[0005] 1) Adding inorganic nanoparticles, but requires grinding and dispersion to stabilize before a high-transparency coating can be obtained, which is costly;

[0006] 2) Adding fluorosilicone additives has poor effects when the amount added is low, and poor compatibility and easy precipitation when the amount added is high;

[0007] 3) Add hydroxyl-containing fluorosilicone modified resin. Fluorosilicone modified resin containing hydroxyl reactive groups has good compatibility with thermosetting resin and can participate in the curing reaction. However, its participation in the curing reaction causes the fluorosilicone resin to be distributed throughout the coating and cannot be concentrated on the coating surface. Therefore, it does not have a good effect on improving the smoothness of the coating.

[0008] Therefore, there is an urgent need in the field to develop a method for preparing coatings that combine excellent slip properties, wear resistance, and elastic self-healing function. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing a coating that has excellent slip properties, wear resistance, and elastic self-healing function.

[0010] In a first aspect, the present invention provides a coating comprising a thermosetting elastic layer located on a substrate and a UV release layer located on a surface layer;

[0011] The coating is prepared as follows:

[0012] 1) Raw materials shall be supplied in the following mass percentages: 10-30% elastic resin, 5-10% modified acrylic resin, 1-5% UV release resin, 10-20% curing agent, 40-60% organic solvent, 0.1-0.5% silicone hand feel agent, 0.1-0.5% leveling agent, 0.1-0.5% defoamer, 0.05-0.2% photoinitiator, and 0.05-0.5% catalyst. The total mass percentage of the above raw materials shall be 100%.

[0013] 2) Add organic solvent to a mixing tank, and while stirring, add elastic resin, modified acrylic resin, UV release resin, silicone hand feel agent, leveling agent, and defoamer in sequence, and disperse at high speed of 2000-3000 rpm for 1-2 hours; then continue to add curing agent, photoinitiator, and catalyst while stirring, and disperse at high speed of 2000-3000 rpm for 0.5-1 hour to obtain a smooth coating with elastic self-healing function;

[0014] 3) The slippery coating with elastic self-healing function is applied to a plastic film, and then subjected to heat curing treatment and UV curing treatment to obtain the coating on the plastic film.

[0015] In another preferred embodiment, the coating consists of a thermosetting elastic layer located on the base layer and a UV release layer located on the surface layer.

[0016] In another preferred embodiment, the thickness of the thermosetting elastic layer is 5-25 μm; and / or

[0017] The thickness of the UV release layer is 0.1-2.5 μm.

[0018] In another preferred embodiment, the thickness of the thermosetting elastic layer is 8-20 μm, more preferably 10-15 μm.

[0019] In another preferred embodiment, the thickness of the UV release layer is 0.3-2 μm, more preferably 0.6-1.5 μm.

[0020] In another preferred embodiment, the surface energy of the coating is 10-30 mN / m.

[0021] In another preferred embodiment, the surface energy of the coating is 15-25 mN / m, more preferably 18-20 mN / m.

[0022] In another preferred embodiment, the coefficient of friction of the coating is 0.05-0.30.

[0023] In another preferred embodiment, the coefficient of friction of the coating is 0.08-0.25, more preferably 0.10-0.20.

[0024] In another preferred embodiment, it has one or more features selected from the group consisting of:

[0025] 1) The elastic resin is a polyester polyol resin;

[0026] 2) The modified acrylic resin is a fluorinated modified acrylic resin;

[0027] 3) The surface tension of the UV release resin is 10-20 mN / m.

[0028] In another preferred embodiment, the molecular weight of the elastic resin is 1000-2000, more preferably 1000-1500.

[0029] In another preferred embodiment, the glass transition temperature of the elastic resin is < -50°C, more preferably -80 to -60°C.

[0030] In another preferred embodiment, the elastic resin is selected from the group consisting of P-2010, P-1010, or combinations thereof.

[0031] In another preferred embodiment, the modified acrylic resin is L-2800.

[0032] In another preferred embodiment, the surface tension of the UV release resin is 15-20 mN / m.

[0033] In another preferred embodiment, the UV release resin is a fluorocarbon modified resin.

[0034] In another preferred embodiment, the UV release resin is L-8769.

[0035] In another preferred embodiment, the curing agent is selected from the group consisting of Desmodur N3300, N3790, N3800, or combinations thereof.

[0036] In another preferred embodiment, the organic solvent is selected from the group consisting of ethyl acetate, butyl acetate, propylene glycol methyl ether, toluene, methyl isobutyl ketone, or combinations thereof.

[0037] In another preferred embodiment, the silicone feel agent is selected from the group consisting of Silok 3200, Silok 4148, Silok 8817, or combinations thereof.

[0038] In another preferred embodiment, the leveling agent is selected from the group consisting of: DOWSIL 205SL, DOWSIL 401SL, or a combination thereof.

[0039] In another preferred embodiment, the defoamer is selected from the group consisting of DOWSIL 100F, FLOWLEN AC-300HF, or combinations thereof.

[0040] In another preferred embodiment, the photoinitiator is IRGACURE 184.

[0041] In another preferred embodiment, the catalyst is DBTDL-T12.

[0042] In another preferred embodiment, the plastic film is selected from the group consisting of TPU and PVC.

[0043] In another preferred embodiment, the thickness of the plastic film is 100-250 μm, more preferably 130-180 μm.

[0044] In another preferred embodiment, the thermosetting temperature is 100-140°C; and / or

[0045] The thermosetting treatment time is 0.5-1.5 hours.

[0046] In another preferred embodiment, the thermosetting temperature is 110-130°C, preferably 120°C.

[0047] In another preferred embodiment, the thermosetting time is 0.8-1.2 hours, preferably 1 hour.

[0048] In another preferred embodiment, the energy density of the UV curing treatment is 500-1500 mJ / cm². 2 .

[0049] In another preferred embodiment, the energy density of the UV curing treatment is 700-1200 mJ / cm². 2 .

[0050] In another preferred embodiment, the coating thickness is 8-20 μm.

[0051] In another preferred embodiment, the coating thickness is 10-18 μm, more preferably 12-15 μm.

[0052] In a second aspect, the present invention provides an article of manufacture comprising the coating described in the first aspect of the present invention.

[0053] In another preferred embodiment, the article is selected from the group consisting of: mobile phones and tablet computers.

[0054] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0055] Through long-term and in-depth research, and by optimizing materials and preparation processes, the inventors have obtained a method for preparing coatings that possess excellent slip properties, wear resistance, and elastic self-healing functions. Specifically, for the raw materials, the inventors selected a specific fluorocarbon modified resin as the UV release resin. After applying the resulting coating, it is first thermo-cured and then UV-cured to obtain a coating with excellent comprehensive performance. Based on this, the inventors completed this invention.

[0056] This invention constructs a very thin UV release slip layer on the surface of a thermosetting elastic self-healing coating through a combined curing method, which greatly improves the slip performance while ensuring elastic self-healing.

[0057] Specifically, in this invention, after the coating is applied to plastic films such as TPU and PVC, a combined curing technology is used, namely, first thermal curing and then UV curing, to prepare a coating that has excellent smoothness, wear resistance and elastic self-healing function.

[0058] This invention first provides a slip-resistant coating with elastic self-healing function. After coating and film formation, a combined curing technology is used: first, thermal curing is performed to obtain an elastic self-healing base layer, providing excellent wear resistance and self-healing properties. Then, UV curing is performed to form a release thin layer on the coating surface, significantly improving slip resistance.

[0059] This invention preferably uses an elastic resin with a low glass transition temperature. The cured coating exhibits excellent resilience, good wear resistance, and strong self-healing ability. The preferred UV release resin is a fluorocarbon modified resin with low surface tension. During the first thermal curing step, it does not participate in the curing reaction but migrates to the coating surface. After UV curing, a very thin, slip-resistant release layer is formed on the coating surface. The thermally cured base elastic coating provides self-healing properties; the surface UV release layer provides slip resistance. When applied to flexible protective films for 3C electronic curved screens, its excellent flexibility facilitates adhesion to flexible curved screens, resulting in a complete fit around the curved edges. Scratches caused by sharp objects such as keys, plastic, and fingernails can be automatically repaired. Furthermore, the excellent slip resistance results in a low coefficient of friction, making screen operation smoother. The low surface energy of the release coating also provides good stain resistance and fingerprint resistance.

[0060] More specifically, the coating of the present invention is prepared as follows:

[0061] 1) Raw materials shall be supplied in the following mass percentages: 10-30% elastic resin, 5-10% modified acrylic resin, 1-5% UV release resin, 10-20% curing agent, 40-60% organic solvent, 0.1-0.5% silicone hand feel agent, 0.1-0.5% leveling agent, 0.1-0.5% defoamer, 0.05-0.2% photoinitiator, and 0.05-0.5% catalyst. The total mass percentage of the above raw materials shall be 100%.

[0062] 2) The above raw material mixture is dispersed at high speed to obtain a smooth coating with elastic self-healing function:

[0063] Add solvent to a mixing tank, and while stirring, add elastic resin, modified acrylic resin, UV release resin, silicone hand feel agent, leveling agent, and defoamer in sequence, dispersing at high speed of 2000-3000 rpm for 1-2 hours. Then, while continuing to stir, add curing agent, photoinitiator, and catalyst, dispersing at high speed of 2000-3000 rpm for 0.5-1 hour to obtain a smooth coating with elastic self-healing function.

[0064] The elastic resin is a polyester polyol resin with a molecular weight of 1000-2000 and a glass transition temperature of less than -50°C, specifically at least one of P-2010 and P-1010.

[0065] The modified acrylic resin is a fluorinated modified acrylic resin containing hydroxyl functional groups, specifically L-2800.

[0066] The UV release resin is a fluorocarbon modified resin containing double bond functional groups, specifically L-8769.

[0067] The curing agent is an HDI trimer, specifically at least one of Desmodur N3300, N3790, and N3800.

[0068] The organic solvent is at least one of ethyl acetate, butyl acetate, propylene glycol methyl ether, toluene, and methyl isobutyl ketone.

[0069] The aforementioned silicone feel agent is a crosslinkable silicone resin, specifically at least one of Silok 3200, Silok 4148, and Silok 8817.

[0070] The leveling agent is at least one of DOWSIL 205SL and DOWSIL 401SL.

[0071] The defoamer is at least one of DOWSIL 100F and FLOWLEN AC-300HF.

[0072] The photoinitiator is a free radical photoinitiator, specifically IRGACURE 184.

[0073] The catalyst is an organotin catalyst, specifically dibutyltin dilaurate DBTDL-T12.

[0074] More specifically, the coating of the present invention is prepared as follows:

[0075] The elastic, self-healing, and smooth coating is applied to TPU, PVC, or other plastic films, first cured in an oven at 100-120℃ for 0.5-1 hour, and then irradiated with 500-1500 mJ / cm² using a UV curing machine. 2 This process yields the smooth coating with elastic self-healing function.

[0076] Compared with the prior art, the present invention has the following main advantages:

[0077] (1) The coating obtained by the method of the present invention has excellent smoothness, wear resistance and elastic self-healing function;

[0078] (2) The method described in this invention is formed by combined curing technology, requiring only one coating application, thus saving energy and reducing emissions.

[0079] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are by weight.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0081] raw material

[0082]

[0083]

[0084] General testing methods

[0085] coefficient of friction

[0086] The coefficient of dynamic friction of the coated surface was tested using non-woven fabric as the friction pair, and the test standard was in accordance with GBT10006-2021.

[0087] Self-healing properties (or abrasion resistance)

[0088] At room temperature of 25℃, the coating was scraped 10 times with a copper brush under a load of 2kg. The time it took for the scratches to automatically heal to a scratch-free state was then observed.

[0089] Water contact angle

[0090] The water contact angle of the coating surface was tested using a water contact angle tester, and the test standard was in accordance with GB / T 30693-2014.

[0091] Surface energy

[0092] The surface energy of the coating is tested using a dyne pen and is divided into five levels: 18mN / m, 20mN / m, 28mN / m, 32mN / m, and 38mN / m.

[0093] Stain resistance

[0094] Use a Chenguang oil-based marker to draw on the coating surface. After 10 seconds, wipe the marks with alcohol and observe the film surface. No mark indicates excellent stain resistance, slight mark indicates good stain resistance, and obvious mark indicates poor stain resistance.

[0095] Example 1

[0096] A combined curing method is used to prepare a smooth coating 1 with elastic self-healing function. The coating 1 is composed of the following raw materials by mass percentage: 20% P-1010 elastic resin, 8% L-2800 modified acrylic resin, 2% L-8769 UV release resin, 13% N3790 curing agent, 56.4% organic solvent ethyl acetate, 0.2% Silok 3200 silicone hand feel agent, 0.1% DOWSIL401SL leveling agent, 0.1% DOWSIL 100F defoamer, 0.1% IRGACURE 184 photoinitiator, and 0.1% DBTDL-T12 catalyst.

[0097] The preparation steps for coating 1 are as follows:

[0098] Solvent was added to a mixing tank, and while stirring, elastic resin, modified acrylic resin, UV release resin, silicone hand feel agent, leveling agent, and defoamer were added sequentially, and dispersed at 2000 rpm for 1 hour. Then, while continuing to stir, curing agent, photoinitiator, and catalyst were added, and dispersed at 2000 rpm for 1 hour to obtain a smooth coating 1 with elastic self-healing function.

[0099] The preparation steps for coating 1 are as follows:

[0100] A smooth coating 1 with elastic self-healing function was applied to a TPU film (150 μm thick) and prepared by the following combined curing method: first, it was heat-cured in an oven at 120°C for 1 hour, and then irradiated with 700 mJ / cm² using a UV curing machine. 2 Thus, the slippery coating 1 with elastic self-healing function is obtained.

[0101] According to calculations, the thickness of the coating 1 is 12μm, the surface energy of the coating 1 is 20mN / m, the stain resistance of the coating 1 is excellent, and the wear resistance of the coating 1 is such that scratches can be automatically repaired in seconds.

[0102] Furthermore, based on the solid content ratio calculation, the coating 1 comprises a thermosetting elastic layer located on the base layer and a UV release layer located on the surface layer, with thicknesses of 11.4 μm and 0.6 μm, respectively.

[0103] Example 2

[0104] A combined curing method is used to prepare a smooth coating 2 with elastic self-healing function. The coating 2 is composed of the following raw materials in the following percentages by mass: P-2010 elastic resin 30%, L-2800 modified acrylic resin 5%, L-8769 UV release resin 5%, N-3800 curing agent 18%, organic solvent ethyl acetate 41%, Silok 3200 silicone hand feel agent 0.5%, DOWSIL401SL leveling agent 0.1%, DOWSIL 100F defoamer 0.1%, IRGACURE 184 photoinitiator 0.2%, and DBTDL-T12 catalyst 0.1%.

[0105] The preparation steps for coating 2 are as follows:

[0106] Solvent was added to a mixing tank, and while stirring, elastic resin, modified acrylic resin, UV release resin, silicone hand feel agent, leveling agent, and defoamer were added sequentially, and dispersed at 2000 rpm for 1 hour. Then, while continuing to stir, curing agent, photoinitiator, and catalyst were added, and dispersed at 2000 rpm for 1 hour to obtain a smooth coating 2 with elastic self-healing function.

[0107] The preparation steps for coating 2 are as follows:

[0108] A smooth coating 2 with elastic self-healing function was applied to a TPU film (150 μm thick) and prepared by the following combination of curing methods: first, heat curing in a 120°C oven for 1 hour, followed by UV curing at 1200 mJ / cm². 2 Thus, the slippery coating 2 with elastic self-healing function is obtained.

[0109] According to calculations, the thickness of the coating 2 is 15μm, the surface energy of the coating 2 is 18mN / m, the stain resistance of the coating 2 is excellent, and the wear resistance of the coating 2 is such that scratches can be automatically repaired in seconds.

[0110] Furthermore, based on the solid content ratio calculation, the coating 2 comprises a thermosetting elastic layer located on the base layer and a UV release layer located on the surface layer, with thicknesses of 13.5 μm and 1.5 μm, respectively.

[0111] Comparative Example 1 (UV-free release resin)

[0112] A smooth coating C1 with elastic self-healing function is composed of the following raw materials by mass percentage: 30% P-2010 elastic resin, 10% L-2800 modified acrylic resin, 18% N-3800 curing agent, 41.2% ethyl acetate organic solvent, 0.5% Silok 3200 silicone hand feel agent, 0.1% DOWSIL 401SL leveling agent, 0.1% DOWSIL 100F defoamer, and 0.1% DBTDL-T12 catalyst.

[0113] The preparation steps for coating C1 are as follows:

[0114] Solvent was added to a mixing tank, and while stirring, elastic resin, modified acrylic resin, silicone hand feel agent, leveling agent, and defoamer were added sequentially, and dispersed at 2000 rpm for 1 hour. Then, while continuing to stir, curing agent and catalyst were added, and dispersed at 2000 rpm for 1 hour to obtain a smooth coating C1 with elastic self-healing function.

[0115] The preparation steps for coating C1 are as follows:

[0116] The slip coating C1 with elastic self-healing function is coated on a TPU film (150μm thick) and then cured in an oven at 120℃ for 1 hour to obtain the slip coating C1 with elastic self-healing function.

[0117] According to calculations, the thickness of the coating C1 is 15μm, the surface energy of the coating C1 is 32mN / m, the stain resistance of the coating C1 is poor, and the wear resistance of the coating C1 is automatic scratch repair in seconds.

[0118] Furthermore, according to thickness gauge testing, the coating C1 consists only of a thermosetting elastic layer located in the base layer, with a thickness of 15 μm.

[0119] Comparative Example 2

[0120] Same as Example 1, except that: Fluorine-modified UV resins Fluere UV 370 (Shenzhen Zhongfu Technology Co., Ltd., surface tension 10-20mN / m), MILO AFS 701 (Shanghai Yadu Lubricating Materials Co., Ltd., surface tension 10-20mN / m), AGLEX-998 (Ao Ke New Materials Technology Co., Ltd., surface tension 10-20mN / m), KY-1203 (purchased from Shin-Etsu Chemical Industry Co., Ltd., surface tension 10-20mN / m), and DAC-HP (purchased from Daikin Fluorochemicals, surface tension 10-20mN / m) were used to replace 2% of L-8769UV release resin to obtain coatings C2-C6.

[0121] The C2-C6 coatings became cloudy and separated into different phases after standing for a short time, indicating that they were no longer usable.

[0122] The coating effects obtained in each embodiment and comparative example are shown in Table 1 below.

[0123] Table 1

[0124] coefficient of friction Self-healing performance Water contact angle Example 1 0.18 Scratches self-heal within 1 second 105° Example 2 0.13 Scratches self-heal within 1 second 107° Comparative Example 1 0.34 Scratches self-heal within 1 second 99°

[0125] As can be seen from the data in Table 1, the coatings prepared by the combined curing method of first thermal curing and then UV curing in Examples 1-2 of the present invention have a low coefficient of friction, good self-healing performance, and a large water contact angle, exhibiting both excellent elastic self-healing and slip properties. In contrast, the coating prepared by Comparative Example 1 using only thermal curing has good self-healing performance, but a high coefficient of friction, a small water contact angle, and only moderate slip properties.

[0126] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A coating, characterized in that, The coating comprises a thermosetting elastic layer located on the base layer and a UV release layer located on the surface layer; The coating is prepared as follows: 1) Raw materials shall be supplied in the following mass percentages: 10-30% elastic resin, 5-10% modified acrylic resin, 1-5% UV release resin, 10-20% curing agent, 40-60% organic solvent, 0.1-0.5% silicone hand feel agent, 0.1-0.5% leveling agent, 0.1-0.5% defoamer, 0.05-0.2% photoinitiator, and 0.05-0.5% catalyst. The total mass percentage of the above raw materials shall be 100%. 2) Add organic solvent to a mixing tank, and while stirring, add elastic resin, modified acrylic resin, UV release resin, silicone hand feel agent, leveling agent, and defoamer in sequence, and disperse at high speed of 2000-3000 rpm for 1-2 hours; then continue to add curing agent, photoinitiator, and catalyst while stirring, and disperse at high speed of 2000-3000 rpm for 0.5-1 hour to obtain a smooth coating with elastic self-healing function; 3) The slippery coating with elastic self-healing function is applied to a plastic film, and then subjected to heat curing treatment and UV curing treatment to obtain the coating on the plastic film.

2. The coating as described in claim 1, characterized in that, The coating consists of a thermosetting elastic layer on the base layer and a UV release layer on the surface layer.

3. The coating as described in claim 1, characterized in that, The thickness of the thermosetting elastic layer is 5-25 μm; and / or The thickness of the UV release layer is 0.1-2.5 μm.

4. The coating as described in claim 1, characterized in that, The surface energy of the coating is 10-30 mN / m.

5. The coating as described in claim 1, characterized in that, The coefficient of friction of the coating is 0.05-0.

30.

6. The coating as described in claim 1, characterized in that, It has one or more characteristics selected from the following group: 1) The elastic resin is a polyester polyol resin; 2) The modified acrylic resin is a fluorinated modified acrylic resin; 3) The surface tension of the UV release resin is 10-20 mN / m.

7. The coating as described in claim 1, characterized in that, The thermosetting temperature is 100-140℃; and / or The thermosetting treatment time is 0.5-1.5 hours.

8. The coating as described in claim 1, characterized in that, The energy density of the UV curing treatment is 500-1500 mJ / cm². 2 .

9. The coating as described in claim 1, characterized in that, The coating thickness is 8-20 μm.

10. An article characterized in that, The article comprises the coating of claim 1.

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