Water-based UV resin and elastic paint prepared from same

Abstract

The invention provides a water-based UV (ultraviolet) resin which comprises the following components in parts by weight: 5-20 parts of diisocyanate; 35 to 50 parts by weight of dihydric alcohol; 0.2-5 parts by weight of a chain extender; 1-20 parts by weight of an end-capping reagent; 30-50 parts by weight of a solvent; and 0.01 to 0.1 part by weight of a catalyst. The invention also provides a preparation method of the water-based UV resin and elastic paint prepared from the water-based UV resin. The elastic paint prepared from the water-based UV resin disclosed by the invention has a thick hand feeling and high tolerance.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically, to a waterborne UV resin and its preparation method. The invention also relates to dispersions and elastic paints prepared from the waterborne UV resin. Background Technology

[0002] In the 3C electronics and cosmetics industries, coatings are widely used to improve the appearance, durability, and scratch resistance of plastic products. With technological advancements, users have developed demands for a smooth, tactile feel. To meet these demands, the industry has developed elastic paints. Elastic paints, also known as tactile paints, are two-component PU coatings made primarily of flexible polyester, combined with aliphatic isocyanate curing agents. They are mainly used on ABS, PC, and other substrates, and are particularly suitable for coating products such as mobile phones, computers, mice, and microphones.

[0003] However, existing elastic paints have always had the problem of not being able to achieve both durability and a good feel; resins with a good feel have poor durability, while resins with exceptionally good durability have a poor feel.

[0004] Therefore, this is a pain point in the industry, and there is a desire for a flexible paint that has a thick feel and high durability. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides an aqueous UV resin, comprising, by weight parts:

[0006] 5-20 parts by weight of diisocyanate;

[0007] 35-50 parts by weight of diol;

[0008] Chain extender 0.2-5 parts by weight;

[0009] 1-20 parts by weight of capping agent;

[0010] Solvent 30-50 parts by weight;

[0011] Catalyst 0.01-0.1 parts by weight.

[0012] Preferably, the aqueous UV resin of the present invention comprises, by weight parts:

[0013] 5-10 parts by weight of diisocyanate;

[0014] 35-45 parts by weight of diol;

[0015] Chain extender 0.5-1.0 parts by weight;

[0016] 2-12 parts by weight of capping agent;

[0017] Solvent 35-45 parts by weight;

[0018] Catalyst 0.01-0.05 parts by weight.

[0019] Preferably, the aqueous UV resin according to the present invention is characterized in that the diisocyanate is at least one selected from hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0020] Preferably, the aqueous UV resin according to the present invention is characterized in that the diol is at least one of polyester diol and polycarbonate diol.

[0021] Preferably, the aqueous UV resin according to the present invention is characterized in that the diol comprises polycarbonate diol and polyether diol, which are used in combination.

[0022] Using polycarbonate diol as the main material gives the resin good hydrolysis resistance and wear resistance.

[0023] Using hydrophilic polyether (polyethylene glycol PPG) to prepare nonionic resin can increase the proportion of soft segments and enhance the feel of thicker material.

[0024] The innovative molecular structure, with double bonds distributed throughout the polymer chain rather than at both ends, imparts better elasticity to the paint film.

[0025] Preferably, the aqueous UV resin according to the present invention is characterized in that the chain extender is at least one selected from polyethylene glycol, polypropylene glycol, and 1,4-butanediol.

[0026] Preferably, the aqueous UV resin according to the present invention is characterized in that the capping agent is pentaerythritol triacrylate.

[0027] Preferably, the aqueous UV resin according to the present invention is characterized in that the solvent is at least one selected from butyl acetate, ethyl acetate, and butanone.

[0028] Preferably, in the aqueous UV resin according to the present invention, the catalyst is dibutyltin laurylate.

[0029] The present invention also provides a method for preparing the aqueous UV resin according to claim 1, comprising:

[0030] Diisocyanate, diol, chain extender, solvent and catalyst are mixed evenly and reacted at a certain temperature for a period of time to reach the predetermined NCO% value;

[0031] Add the end-capping agent, continue the reaction for a period of time, and after reaching the predetermined NCO% value, cool down and discharge the material.

[0032] This invention provides the following technical effects:

[0033] 1. The waterborne UV resin of the present invention uses polycarbonate diol as the main material, which gives the resin good hydrolysis resistance, wear resistance and other properties. Therefore, the elastic paint made from the resin of the present invention has wear resistance.

[0034] 2. The waterborne UV resin of this invention uses hydrophilic polyether (polyethylene glycol PPG) to prepare a nonionic resin, which can increase the proportion of soft segments, enhance the thick feel, and meet the requirements of elastic paint for feel.

[0035] 3. The molecular structure of the waterborne UV resin of this invention is innovatively designed, with double bonds distributed in the polymer chain rather than at both ends, which can give the prepared elastic film better elasticity. Detailed Implementation

[0036] The present invention will now be described through specific embodiments.

[0037] [Preparation of waterborne UV resin]

[0038] The aqueous UV resin of the example was prepared according to the composition ratios shown in Table 1, as follows:

[0039] Hexamethylene diisocyanate, diol (a mixture of polycarbonyl diol and polyether diol), 1,4-butanediol, butanone and dibutyltin laurylate are mixed evenly and reacted at a certain temperature for a period of time to reach the predetermined NCO% value.

[0040] Add pentaerythritol triacrylate, continue the reaction for a period of time, and after reaching the predetermined NCO% value, cool down and discharge the material.

[0041] Table 1. Composition (parts by weight) of the aqueous UV resins according to Examples 1-4 of the present invention

[0042] Example 1 Example 2 Example 3 Example 4 Hexamethylene diisocyanate 8.0 8.1 9.1 9.1 Polyether diol 8.0 16.1 18.1 18 Polycarbodiol 35.0 25.8 29.0 21.6 1,4-Butanediol 0.6 0.3 1.6 0.6 Pentaerythritol triacrylate 9.5 9.6 2.2 10.7 Butanone 40 40 40 40 Dibutyltin lauryl ester 0.02 0.02 0.02 0.02

[0043] The aqueous UV resins of Comparative Examples 1-3 were prepared in the same manner as those in the examples above, according to the composition ratios shown in Table 2.

[0044] Table 2. Composition (parts by weight) of waterborne UV resins according to Comparative Examples 1-3

[0045] Comparative Example 1 Comparative Example 2 Comparative Example 3 Hexamethylene diisocyanate 8.0 12 10.7 Polyether diol 8.0 43 -- Polycarbodiol -- -- 25.6 Polyester diol 35.0 -- -- 2,2-Dimethylolpropionic acid -- -- 4 1,4-Butanediol 0.6 2.1 1.9 Pentaerythritol triacrylate 10.1 2.8 17.8 Butanone 40 40 40 Dibutyltin lauryl ester 0.02 0.02 0.02

[0046] [Preparation of Elastic Paint]

[0047] The elastic paint prepared by the waterborne UV resin according to the present invention is prepared in the following manner:

[0048] Phase inversion method for preparing dispersion: The aqueous UV resin of the present invention in Examples 1-4 above is placed in an emulsification tank, stirring is started, and water is added in four batches of 30%, 30%, 20%, and 20%, with an interval of 20 minutes between each addition. Finally, stirring is continued for 30 minutes, and the solvent is removed under reduced pressure to obtain the aqueous UV resin dispersion according to Examples 1-4.

[0049] 84.5 parts by weight of the resin dispersions prepared in Examples 1-4 were added to a container, followed by 8.5 parts by weight of water, 0.2 parts by weight of dispersant, 0.1 parts by weight of leveling agent, and 1 part by weight of photoinitiator. The mixture was dispersed for 20 minutes, and then 5.7 parts by weight of matting powder were added while dispersing, and dispersion was continued for another 30 minutes. The mixture was allowed to stand for 30 minutes and then filtered through a filter cloth. The elastic paints of Examples 1-4 according to the present invention were obtained.

[0050] The elastic paints of Comparative Examples 1-3 were prepared using the resin dispersions of Comparative Examples 1-3 in the same manner as in the above embodiments.

[0051] [Performance Test of Elastic Paint Before Curing]

[0052] The prepared elastic paint was subjected to the following performance tests:

[0053] 1. Viscosity:

[0054] Measured according to GB / T 15357-2014, using a rotational viscometer at 25 degrees Celsius, the viscosity should be less than 1000 cP. The lower the viscosity, the better the coating's workability and the easier it is to spray.

[0055] 2. pH

[0056] According to GB / T 18012-2021, the pH value of elastic paint shall be measured, with a range of 4.0-7.0.

[0057] 3. Solid content

[0058] 150 degrees Celsius, measured for 1 hour, 20-50%.

[0059] Table 3. Pre-curing properties of the elastic paints according to Examples 1-4 of the present invention

[0060] Test Project Example 1 Example 2 Example 3 Example 4 Appearance Milky white blue light Blue light translucent Milky white with weak blue light Milky white blue light pH 5.4 6.2 5.6 5.5 Solid content / % 40 40 40 40 Viscosity / cP 320 280 260 300

[0061] Table 4. Pre-curing properties of the elastic paints from Comparative Examples 1-3

[0062] Test Project Comparative Example 1 Comparative Example 2 Comparative Example 3 Appearance Milky white blue light Blue light transparent Milky white blue light pH 5.2 5.5 8.6 Solid content / % 40 40 45 Viscosity / cP 250 360 74

[0063] [Performance Test of Elastic Paint After Curing]

[0064] The prepared elastic paint was sprayed onto an ABS+PC substrate, baked at 60 degrees Celsius for 15 minutes, and then radiation cured (500-1000 mJ / cm²). 2 (Energy curing). The following performance tests were performed on the cured paint film.

[0065] 1. Paint film feel

[0066] Touch the surface of the paint film directly with your hand and feel it.

[0067] 2. Boiling:

[0068] Boil in water at 60℃ for 1 hour, then observe whether the paint film bubbles or turns white.

[0069] 3. Resistant to high temperature and humidity

[0070] Place the paint film at 60℃ and 90% humidity for 72 hours, then touch the film with your hand to observe whether it becomes sticky again.

[0071] 4. Hardness

[0072] According to GB / T 6739-2022, the pencil hardness of the cured paint film should be tested, and the pencil should meet the requirements for high-grade graphite pencils in GB / T26704-2011.

[0073] Table 5. Test results of the elastic paint according to Examples 1-4

[0074] Test Project Example 1 Example 2 Example 3 Example 4 Paint film feel Thick and comfortable Thick and comfortable Thick and comfortable Thick and comfortable Resistant to boiling No abnormalities No abnormalities No abnormalities No abnormalities High temperature and humidity resistance No abnormalities No abnormalities No abnormalities No abnormalities Pencil hardness 4B 4B 3B 3B

[0075] Table 6. Test results of elastic paints based on Comparative Examples 1-3

[0076]

[0077] The pH of the elastic paints in Examples 1-4 of this invention is lower than 7 because the present invention prepares a nonionic resin.

[0078] The hardness of the elastic paint in Examples 1-4 of this invention is less than 2B, indicating that the surface of the paint film has soft properties after curing, which objectively characterizes the feel of the paint film.

[0079] The test results of resistance to damp heat show that the elastic paints of Examples 1-4 of the present invention have good resistance.

[0080] While embodiments of the invention have been described herein, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-based UV resin, comprising, by weight:

2. The waterborne UV resin according to claim 1, wherein, By weight, its composition includes:

3. The aqueous UV resin according to claim 1, characterized in that, The diisocyanate is at least one of hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

4. The waterborne UV resin according to claim 1, characterized in that, The diols include polycarbonate diols and polyether diols, which are used in combination.

5. The waterborne UV resin according to claim 1, characterized in that, The chain extender is at least one of polyethylene glycol, polypropylene glycol, and 1,4-butanediol.

6. The aqueous UV resin according to claim 1, characterized in that, The capping agent is pentaerythritol triacrylate.

7. The aqueous UV resin according to claim 1, characterized in that, The solvent is at least one of butyl acetate, ethyl acetate, and butanone.

8. The waterborne UV resin according to claim 1, characterized in that, The catalyst is dibutyltin lauryl laurate.

9. A method for preparing the aqueous UV resin according to claim 1, comprising: Diisocyanate, diol, chain extender, solvent and catalyst are mixed evenly and reacted at a certain temperature for a period of time to reach the predetermined NCO% value; Add the end-capping agent, continue the reaction for a period of time, and after reaching the predetermined NCO% value, cool down and discharge the material.

10. An aqueous resin dispersion, comprising: The aqueous UV resin according to claim 1; water.

11. An elastic paint, comprising: The waterborne UV resin according to claim 1; photoinitiator; leveling agent; dispersant; matting agent; water.

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