Preparation method of a matte resin

Abstract

The present invention provides a method for preparing a matte resin. The preparation method includes a first stage and a second stage. The first stage includes preparing a chlorinated polypropylene-modified thermoplastic acrylic resin by using chlorinated polypropylene, a first comonomer raw material and a first initiator, and the weight-average molecular weight of the chlorinated polypropylene-modified thermoplastic acrylic resin is 30,000 to 50,000. The second stage includes adding a second comonomer raw material and a second initiator to the product obtained in the first stage to prepare a hydroxy acrylic resin. The second comonomer raw material, based on 100 parts by total weight thereof, includes 28 to 34 parts of methyl methacrylate, 13 to 16 parts of butyl acrylate, 26 to 32 parts of tert-butyl acrylate, and 25 to 30 parts of 2-hydroxyethyl methacrylate. The acrylic resin prepared by the method of the present invention successfully achieves a matte effect and broadens the application scope of acrylic resins.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a method for preparing a matte resin. Background Art

[0002] The glossiness of a resin is an important performance index of a coating. Especially for applications that require a matte effect, such as automotive interior coatings, wood coatings, etc., the matte effect can provide a more beautiful and comfortable visual experience. However, due to its high glossiness, traditional acrylic resins are difficult to achieve a matte effect, which limits their application in specific fields. Therefore, developing a new type of matte resin is of great significance for meeting market demands. Summary of the Invention

[0003] To solve the above technical problems, on the one hand, the present invention provides a method for preparing a matte resin, wherein the preparation method includes a first stage and a second stage;

[0004] The first stage includes preparing a chlorinated polypropylene-modified thermoplastic acrylic resin using chlorinated polypropylene, a first comonomer raw material, and a first initiator, and the weight-average molecular weight of the chlorinated polypropylene-modified thermoplastic acrylic resin is 30,000 to 50,000;

[0005] The second stage includes adding a second comonomer raw material and a second initiator to the product obtained in the first stage to prepare a hydroxy acrylic resin;

[0006] The second comonomer raw material, based on 100 parts by total weight, includes 28 to 34 parts of methyl methacrylate, 13 to 16 parts of butyl acrylate, 26 to 32 parts of tert-butyl acrylate, and 25 to 30 parts of 2-hydroxyethyl methacrylate;

[0007] The ratio of the total weight of the chlorinated polypropylene and the first comonomer raw material to the total weight of the second comonomer raw material is 1:3 to 1:2;

[0008] The reaction temperature in the second stage is controlled at 123 to 127 °C.

[0009] In a preferred technical solution of the present application, the reaction in the second stage includes: heating a reaction kettle loaded with the product of the first stage and an organic solvent to 123 to 127 °C, and adding the mixture in a second dropping kettle to the reaction kettle over 2 to 4 hours and maintaining the temperature for at least 0.5 hour; the mixture in the second dropping kettle is a mixture of the second comonomer raw material and the second initiator; the second initiator is tert-butyl peroxy-3,5,5-trimethylhexanoate;

[0010] Preferably, after the heat preservation is completed, an organic solvent and the second initiator are additionally added, and heat preservation is continued for at least 0.5 hour;

[0011] Preferably, the reaction temperature in the second stage is 125 °C.

[0012] In a preferred technical solution of the present application, the first comonomer raw material includes methyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl methacrylate, and methacrylic acid;

[0013] The reaction temperature in the first stage is controlled at 88-92 °C; preferably, the reaction temperature in the first stage is 90 °C.

[0014] In a preferred technical solution of the present application, in the first stage, an organic solvent and chlorinated polypropylene are first added to the reaction kettle and heated to 88-92 °C, and then the mixture in the first dropping kettle is added dropwise to the reaction kettle over 2-4 hours and heat preservation is carried out for at least 1 hour; the mixture in the first dropping kettle is a mixture of the first comonomer raw material and the first initiator.

[0015] In a preferred technical solution of the present application, in the first stage, 10 parts by weight of the organic solvent xylene and 0.5 part by weight of chlorinated polypropylene are first added to the reaction kettle, heated and stirred. After the chlorinated polypropylene is completely dissolved, the mixture in the first dropping kettle is added dropwise to the reaction kettle over 3 hours and heat preservation is carried out for 2 hours; the mixture in the first dropping kettle includes 14.5 parts by weight of the first comonomer raw material and 0.05 part by weight of the first initiator tert-butyl peroxy-2-ethylhexanoate;

[0016] Preferably, the first comonomer raw material includes 6.5 parts by weight of methyl methacrylate, 0.9 part by weight of butyl acrylate, 4 parts by weight of butyl methacrylate, 3 parts by weight of cyclohexyl methacrylate, and 0.1 part by weight of methacrylic acid.

[0017] In a preferred technical solution of the present application, in the second stage, after the heat preservation in the first stage is completed, 15 parts by weight of the organic solvent xylene are continuously added to the reaction kettle, and the temperature is raised to 123-127 °C. The mixture in the second dropping kettle is added dropwise to the reaction kettle over 3 hours and heat preservation is carried out for 1 hour; the mixture in the second dropping kettle includes 35 parts by weight of the second comonomer raw material and 1 part by weight of the second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate;

[0018] Preferably, the second comonomer raw material includes 10.7 parts by weight of methyl methacrylate, 5 parts of butyl acrylate, 10 parts of tert-butyl acrylate, and 9.3 parts of 2-hydroxyethyl methacrylate;

[0019] Preferably, after the second-stage heat preservation for 1 hour, 2 parts by weight of the organic solvent xylene and 0.2 parts by weight of the second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate are additionally added, and the heat preservation is continued for 1 hour.

[0020] On the other hand, the present application provides a matte resin, which is prepared by the above preparation method.

[0021] Preferably, the weight-average molecular weight of the matte resin is 18,000 to 25,000; more preferably, the weight-average molecular weight of the matte resin is 19,000 to 21,000.

[0022] Preferably, the solid content of the matte resin at 100 °C is 48 to 52%, and the viscosity is 5000 - 10000 mPa·s.

[0023] On yet another aspect, the present application provides a coating composition, wherein the coating composition comprises the above-mentioned matte resin.

[0024] On still another aspect, the present application provides the use of the above-mentioned matte resin or the above-mentioned coating composition in the preparation of 3C products.

[0025] The matte resin obtained by the preparation method of the present invention successfully realizes the matte effect of the acrylic resin and broadens its application scope; the matte resin prepared by the method of the present invention has stable product performance and excellent matte effect, and can meet the requirements of specific application fields, such as automotive interiors, wood coatings, etc. The matte effect can provide a more beautiful and comfortable visual experience, enhance the appearance attractiveness of the product, and in application scenarios where light reflection needs to be reduced, the low gloss characteristic of the matte resin helps to reduce visual fatigue and improve the use comfort; the preparation method of the present invention is simple, easy to operate, and easy to realize industrial production, which is beneficial to reducing production costs and improving production efficiency. Detailed Embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0027] The following details each aspect of the present invention. Without specific description, various raw materials of the present invention can be obtained commercially; or prepared according to conventional methods in the art. Unless otherwise defined or described, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0028] In the following examples, the experimental methods without specific conditions are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all parts are by weight and all percentages are by weight percentage.

[0029] The present invention will be further described below through examples, but the present invention is not limited to these specific embodiments.

[0030] Preparation of the matte resin of Example 1

[0031] First stage:

[0032] 1) Charge 10 parts by weight of the organic solvent xylene and 0.5 part by weight of chlorinated polypropylene into the reaction kettle, and heat to 90 °C, heat and stir until the chlorinated polypropylene is completely dissolved; meanwhile, charge 14.5 parts of the first comonomer raw material and 0.05 part by weight of the first initiator tert-butyl peroxy-2-ethylhexanoate into the first dropping kettle; 14.5 parts of the first comonomer raw material includes 6.5 parts by weight of methyl methacrylate, 0.9 part by weight of butyl acrylate, 4 parts by weight of butyl methacrylate, 3 parts by weight of cyclohexyl methacrylate and 0.1 part by weight of methacrylic acid;

[0033] 2) Keep the temperature of the reaction kettle at 90 °C, and drop the mixture in the first dropping kettle into the reaction kettle over 3 hours, while keeping the temperature at 88 - 92 °C.

[0034] 3) After the dropping is completed, keep the temperature at 90 °C for 2 hours;

[0035] After the first stage is completed, take a sample to measure the weight-average molecular weight; the weight-average molecular weight in the range of 30,000 - 50,000 is acceptable.

[0036] Specifically in this example, the weight-average molecular weight of the product in the first stage is about 42,000.

[0037] Second stage:

[0038] a) After the heat preservation in the above first stage is completed, continue to charge 15 parts by weight of the organic solvent xylene into the above reaction kettle, and raise the temperature to 123 - 127 °C; meanwhile, charge 35 parts by weight of the second comonomer raw material and 1 part by weight of the second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate into the second dropping kettle; 35 parts by weight of the second comonomer raw material includes 10.7 parts by weight of methyl methacrylate, 5 parts by weight of butyl acrylate, 10 parts by weight of tert-butyl acrylate, 9.3 parts by weight of 2-hydroxyethyl methacrylate;

[0039] b) Keep the temperature of the reaction kettle at 125 °C, and drop the mixture in the second dropping kettle into the reaction kettle over 3 hours, while keeping the temperature at 123 - 127 °C;

[0040] c) After the dropping is completed, keep it at 125 °C for 1 hour;

[0041] d) Add another 2 parts by weight of the organic solvent xylene and 0.2 parts by weight of the second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate, and continue to keep it warm for 1 hour.

[0042] After the second stage is completed, take a sample to measure the weight-average molecular weight; the weight-average molecular weight in the range of 18,000 - 25,000 is acceptable.

[0043] Specifically in this example, the weight-average molecular weight of the product in the second stage is about 20,000.

[0044] The product of the second stage can be cooled to 100 °C, and the organic solvent xylene is added to adjust the solid content to 48 - 52% wt and the viscosity to 90 - 150 mPa·s. It can be further cooled to 80 °C for testing and packaging.

[0045] Specifically in this example, 22.75 parts by weight of xylene is added to adjust the solid content at 100 °C to about 50% wt, and the viscosity is 5000 - 10000 mPa·s.

[0046] The performance indicators of the matte resin product obtained through Example 1 are as shown in Table 1 below:

[0047] Table 1

[0048]

[0049] Comparative Example 1:

[0050] Only prepare the chlorinated polypropylene-modified thermoplastic acrylic resin according to the first stage of Example 1.

[0051] Put 10 parts by weight of the organic solvent xylene and 0.5 parts by weight of chlorinated polypropylene into the reaction kettle and heat to 90 °C; at the same time, put 14.5 parts of the first comonomer raw material and 0.05 parts by weight of the first initiator tert-butyl peroxy-2-ethylhexanoate into the first dropping kettle; 14.5 parts of the first comonomer raw material includes 6.5 parts by weight of methyl methacrylate, 0.9 parts by weight of butyl acrylate, 4 parts by weight of butyl methacrylate, 3 parts by weight of cyclohexyl methacrylate, and 0.1 parts by weight of methacrylic acid;

[0052] Keep the temperature of the reaction kettle at 90 °C, and drop the mixture in the first dropping kettle into the reaction kettle in 3 hours, while keeping the temperature at 88 - 92 °C during the dropping;

[0053] After the dropping is completed, keep it at 90 °C for 2 hours.

[0054] Comparative Example 2

[0055] The hydroxyl acrylic resin was only prepared according to the second stage of Example 1, and the steps are as follows:

[0056] 40 parts by weight of xylene was put into the reaction kettle, and 35 parts by weight of the second comonomer raw material and 1 part by weight of the second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate were put into the dropping kettle; the 35 parts by weight of the second comonomer raw material included 10.7 parts by weight of methyl methacrylate, 5 parts of butyl acrylate, 10 parts of tert-butyl acrylate, and 9.3 parts of 2-hydroxyethyl methacrylate.

[0057] Comparative Example 3

[0058] In the first reaction kettle, the chlorinated polypropylene-modified thermoplastic acrylic resin was only prepared according to the first stage of Example 1.

[0059] In the second reaction kettle, the hydroxyl acrylic resin was only prepared according to the second stage of Example 1.

[0060] Finally, the products in the first reaction kettle and the second reaction kettle were mixed.

[0061] The performance data of the products prepared by Example 1 and Comparative Examples 1-3 are compared in Table 2 below:

[0062] Table 2

[0063]

[0064] It can be seen from the results in Table 2 above that the gloss of the chlorinated polypropylene-modified thermoplastic acrylic resin prepared only according to the first stage of Example 1 and the hydroxyl acrylic resin prepared only according to the second stage of Example 1 are both relatively high.

[0065] If the chlorinated polypropylene-modified thermoplastic acrylic resin prepared in the first stage and the hydroxyl acrylic resin prepared in the second stage are directly mixed in the same mass ratio as in Example 1, the appearance of the obtained mixed resin is a turbid liquid, and the gloss is significantly reduced (gloss at a 60° angle).

[0066] However, the gloss of the resin product prepared in Example 1 is still significantly lower than that of Comparative Example 3.

[0067] Specifically, according to the preparation method of Example 1, based on the thermoplastic acrylic resin modified with chlorinated polypropylene within a specific molecular weight range obtained in the first stage, in the same reaction kettle, the second stage of preparation is continued (feeding the reactants and initiator for preparing hydroxy acrylic resin, as well as the corresponding preparation operation methods); theoretically speaking, during the second stage of the process, only the preparation reaction of hydroxy acrylic resin occurs in the reaction kettle, but the inventors of this application unexpectedly found that the product of the first stage already present in the reaction kettle (thermoplastic acrylic resin modified with chlorinated polypropylene, with a weight average molecular weight of 30000 - 50000) may also participate or partially participate in the reaction of the second stage. Finally, compared with the product directly mixed with Comparative Example 3, the glossiness of the resin product of Example 1 is further significantly reduced.

[0068] According to some embodiments of the present invention, the application of preparing a coating composition from the matte resin prepared by the preparation method of the matte resin described in Example 1 includes the following steps:

[0069] Mix the matte resin with a solvent and stir evenly;

[0070] Add pigments and disperse them using a high-speed disperser until the pigments are evenly dispersed;

[0071] Add additives to adjust the rheological properties and application properties of the coating;

[0072] Add crosslinking agents and other auxiliaries to improve the hardness, abrasion resistance and chemical resistance of the coating;

[0073] Cure for a certain period of time under appropriate conditions to ensure the stability of the coating.

[0074] The formulation of the coating composition is as shown in Table 3 below:

[0075] Table 3

[0076]

[0077] The present invention also provides the application of the coating composition containing the matte resin in 3C products.

[0078] According to some embodiments of the present invention, the 3C products of the present invention refer to computers, communication and consumer electronic products.

[0079] The application of the coating composition containing the matte resin of the present invention in 3C products mainly includes:

[0080] Laptop and tablet computer casings: The matte effect can provide a more high-end appearance and feel, while reducing the visibility of fingerprints and stains.

[0081] Mobile phones and smartphone casings: Matte coatings can enhance the aesthetics of the product, provide a better grip, and reduce the risk of slipping.

[0082] TV and monitor bezels: Matte coatings can reduce light reflection and improve the viewing experience.

[0083] Audio devices and household appliances: Matte coatings can provide a durable and easy-to-clean surface while having an aesthetic appearance.

[0084] Internal components of electronic products: Matte coatings can be used on circuit boards or other internal components to provide protection and insulation properties.

[0085] Decoration and personalization: Matte coatings can be used for personalized customization services to provide consumers with unique product appearances.

[0086] In summary, the present invention provides a method for preparing a matte resin. This method synthesizes by controlling the compatibility of thermoplastic acrylic resin and hydroxyl acrylic resin and adopting a segmented dropping method, and successfully prepares a hydroxyl acrylic resin with excellent matte effect. The method of the present invention is simple, easy to operate, the product performance is stable, and it has a wide range of application prospects.

[0087] It should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0088] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a matte resin, characterized in that: The preparation method comprises a first stage and a second stage; The first stage includes preparing a chlorinated polypropylene modified thermoplastic acrylic resin using chlorinated polypropylene, a first comonomer raw material and a first initiator, wherein the weight average molecular weight of the chlorinated polypropylene modified thermoplastic acrylic resin is 30,000 to 50,000; The first comonomer raw material includes methyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl methacrylate and methacrylic acid; The second stage comprises adding a second comonomer raw material and a second initiator into the product obtained in the first stage to prepare a hydroxy acrylic resin; The second comonomer raw material, based on 100 parts by total weight, includes 28 to 34 parts of methyl methacrylate, 13 to 16 parts of butyl acrylate, 26 to 32 parts of tert-butyl acrylate, and 25 to 30 parts of hydroxyethyl methacrylate; The ratio of the total weight of the chlorinated polypropylene and the first comonomer raw material to the total weight of the second comonomer raw material is 1:3 to 1:2; The reaction temperature of the second stage is controlled at 123~127°C.

2. The preparation method according to claim 1, characterized in that: The reaction of the second stage includes: heating the reactor loaded with the product of the first stage and the organic solvent to 123-127° C., adding the mixture in the second dropping kettle to the reactor over 2-4 hours, and keeping warm for at least 0.5 hours; the mixture in the second dropping kettle is a mixture of the second comonomer raw material and the second initiator; the second initiator is tert-butyl peroxy-3,5,5-trimethylhexanoate.

3. The preparation method according to claim 2, characterized in that: After the heat preservation is completed, the organic solvent and the second initiator are added and the heat preservation is continued for at least 0.5 hours.

4. The preparation method according to claim 2, characterized in that: The reaction temperature of the second stage is 125°C.

5. The preparation method according to claim 1 or 2, characterized in that: The reaction temperature of the first stage is controlled at 88-92°C.

6. The preparation method according to claim 5, characterized in that: The reaction temperature of the first stage is 90°C.

7. The preparation method according to claim 5, characterized in that: The first stage includes first adding an organic solvent and chlorinated polypropylene into a reaction kettle and heating it to 88-92° C., then dripping the mixture in the first dropping kettle into the reaction kettle over 2-4 hours and keeping the mixture warm for at least 1 hour; the mixture in the first dropping kettle is a mixture of the first comonomer raw material and the first initiator.

8. The preparation method according to claim 7, characterized in that: In the first stage, 10 parts by weight of an organic solvent xylene and 0.5 parts by weight of chlorinated polypropylene are first added into a reactor, heated and stirred, and the chlorinated polypropylene is completely dissolved. The mixture in the first dropping kettle is then added dropwise to the reactor over 3 hours and kept warm for 2 hours. The mixture in the first dropping kettle includes 14.5 parts by weight of a first comonomer raw material and 0.05 parts by weight of a first initiator tert-butyl peroxy-2-ethylhexanoate.

9. The preparation method according to claim 8, characterized in that: The first comonomer feed includes 6.5 parts by weight of methyl methacrylate, 0.9 parts by weight of butyl acrylate, 4 parts by weight of butyl methacrylate, 3 parts by weight of cyclohexyl methacrylate, and 0.1 parts by weight of methacrylic acid.

10. The preparation method according to claim 8, characterized in that: In the second stage, after the insulation of the first stage is completed, 15 parts by weight of the organic solvent xylene is continued to be added to the reactor, and the temperature is raised to 123-127°C, and the mixture in the second dropping kettle is added dropwise to the reactor over 3 hours, and the mixture is kept warm for 1 hour; the mixture in the second dropping kettle includes 35 parts by weight of the second comonomer raw material and 1 part by weight of the second initiator peroxy-3,5,5-trimethylhexanoic acid tert-butyl ester.

11. The preparation method according to claim 10, characterized in that: The second comonomer raw material includes 10.7 parts by weight of methyl methacrylate, 5 parts by weight of butyl acrylate, 10 parts by weight of tert-butyl acrylate, and 9.3 parts by weight of hydroxyethyl methacrylate.

12. The preparation method according to claim 10, characterized in that: After the second stage is kept warm for 1 hour, 2 parts by weight of an organic solvent xylene and 0.2 parts by weight of a second initiator tert-butyl peroxy-3,5,5-trimethylhexanoate are added, and the heat is kept warm for another 1 hour.

13. A matte resin, characterized in that: The matte resin is prepared by the preparation method according to any one of claims 1 to 12.

14. The matte resin according to claim 13, characterized in that: The weight average molecular weight of the matte resin is 18000-25000.

15. The matte resin according to claim 14, characterized in that: The weight average molecular weight of the matte resin is 19000-21000.

16. The matte resin according to claim 13, characterized in that: The matte resin has a solid content of 48-52% at 100° C. and a viscosity of 5000-10000 mpa.s.

17. A coating composition, characterized in that: The coating composition comprises the matte resin according to any one of claims 13 to 16.

18. Use of the matte resin according to any one of claims 13 to 16 or the coating composition according to claim 17 in the preparation of 3C products.

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