Multifunctional acrylate and use thereof

Abstract

The application belongs to the field of materials, and particularly relates to a multifunctional acrylate and application thereof. The multifunctional acrylate is prepared by the following method: ring-opening reaction of polyol acrylate and maleic anhydride at 100-110 DEG C. The application realizes grafting of the acrylate resin and the UV component by preparing the multifunctional acrylate, the acrylate resin can provide adhesion to the metal plating layer, and the UV component provides the feasibility of UV curing crosslinking. Meanwhile, the different active double bonds provide a multiple crosslinking technical scheme for crosslinking, and greatly improve the adhesion.

Description

Technical Field

[0001] This invention belongs to the field of materials, and particularly relates to a multifunctional acrylate and its applications. Background Technology

[0002] PVD technology has wide applications in the 3C industry. Currently, PVD coatings serve to add color and protect the coating. Solvent-based PVD coatings consist of UV resin, monomers, colorants, additives, and solvents, with solvents accounting for approximately 70-80%. This large amount of solvent leads to serious VOC problems. With increasing environmental awareness, it is necessary to replace the existing solvent-based systems in PVD with water-based systems.

[0003] Currently, traditional PVD intermediate coatings use UV curing, which poses a challenge to color addition, as it is impossible to achieve the required depth of color. This is because depth of color requires very high energy to reach the bottom of the coating film, but high energy also brings about interlayer adhesion problems between the topcoat and the intermediate coating, thus affecting the performance of the system.

[0004] Existing technology CN 104003875 A discloses a hexafunctional aliphatic epoxy acrylate, its preparation method, and its application. First, a trifunctional acrylate intermediate (I) containing one carboxyl group is prepared by reacting succinic anhydride with pentaerythritol triacrylate in the presence of a catalyst and a polymerization inhibitor. Then, the hexafunctional aliphatic epoxy acrylate is prepared by reacting intermediate (I) with neopentyl glycol diglycidyl ether in the presence of a catalyst and a polymerization inhibitor. The prepared hexafunctional UV-curable aliphatic epoxy acrylate, after curing, exhibits excellent properties such as high hardness, wear resistance, scratch resistance, heat resistance, and weather resistance, and can be used as a raw material for UV coatings, inks, and adhesives. However, the phthalic anhydride, succinic anhydride, methylhexahydrophthalic anhydride and hexahydrophthalic anhydride used do not have double bonds, and cannot provide double bonds with different activities, thus failing to provide good interlayer adhesion; although tetrahydrophthalic anhydride has a double bond, the activity of this double bond is extremely low and the steric hindrance is large, so it basically does not participate in cross-linking, and similarly cannot provide good interlayer adhesion. Summary of the Invention

[0005] This invention provides a multifunctional acrylate that utilizes the difference in double bond activity to provide different curing speeds, thereby providing excellent interlayer adhesion.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A multifunctional acrylate is prepared by the following method: a ring-opening reaction of a polyol acrylate with maleic anhydride at 100-110°C.

[0008] In one preferred embodiment, the polyol acrylate is pentaerythritol triacrylate.

[0009] In one preferred embodiment, a catalyst is added to the ring-opening reaction, wherein the catalyst is triphenylphosphine, benzyltriethylammonium bromide, triethylamine or tetrabutylammonium bromide; triphenylphosphine is preferred from the perspective of reaction rate and yellowing.

[0010] A ring-opening reaction is performed between pentaerythritol triacrylate and maleic anhydride under the catalysis of triphenylphosphine at 100-110℃ to generate a polyfunctional acrylate with carboxyl groups and double bonds. The double bonds in this compound have two parts: the double bonds on the pentaerythritol triacrylate are highly reactive and can be rapidly cured under UV light, thus providing high performance for the intermediate coat. The double bonds introduced on the maleic anhydride are relatively less reactive; during the curing of the intermediate coat, these double bonds on the surface are difficult to cure due to oxygen inhibition. After the topcoat is applied, the uncured double bonds on the intermediate coat surface cross-link with the double bonds in the topcoat, resulting in better interlayer adhesion between the intermediate coat and the topcoat.

[0011] The synthetic route for the multifunctional acrylate is as follows:

[0012]

[0013] This invention also claims protection for a UV resin whose raw materials include 90-150 parts of a high-TG monomer with double bonds and 450-750 parts of a polyfunctional acrylate.

[0014] In one preferred embodiment, the UV resin comprises 90-150 parts of a high-TG monomer with double bonds, 335-410 parts of acrylate, 4-6 parts of phosphate ester, 450-750 parts of multifunctional acrylate, and 5-10 parts of catalyst.

[0015] In one preferred embodiment, the UV resin comprises 90-150 parts of high-TG monomer with double bonds, 120-140 parts of methyl methacrylate, 35-45 parts of methoxy polyethylene glycol methacrylate, 90-110 parts of glycidyl methacrylate, 90-110 parts of hydroxypropyl acrylate, 4-6 parts of 2-hydroxyethyl methacrylate phosphate, 450-750 parts of polyfunctional acrylate, and 5-10 parts of triphenylphosphine.

[0016] In the resin, if the amount of high-TG monomers with double bonds is less than 90 parts, poor adhesion will occur, while too much will cause yellowing and failure to pass the test. If the amount of methoxy polyethylene glycol methacrylate added is too low, it will not provide sufficient water-based properties; if too much, it will lead to poor water resistance. If the amount of GMA added is too low, sufficient UV components cannot be grafted on; if too much, it will affect water resistance. If the amount of HPA added is too low, the thermosetting crosslinking density will be insufficient; if too much, hydroxyl residue will affect water resistance. If the amount of 2-hydroxyethyl methacrylate phosphate added is too low, it will affect adhesion; if too much, it will become too hydrophilic, affecting water resistance. The amount of each component added is strictly controlled according to the resin structure design; too much or too little will have adverse effects on the structure and properties of the resin.

[0017] This invention employs a free radical polymerization approach, using methoxy polyethylene glycol methacrylate as a nonionic hydrophilic monomer. High-TG monomers with double bonds provide adhesion to metals, while HPA and GMA act as crosslinking monomers. Crosslinking with the curing agent in the coating improves the water resistance and chemical resistance of the paint film. The intermediate reacts with the epoxy groups on GMA to graft UV components onto the resin molecular chain.

[0018] In one preferred embodiment, the TG value of the high-TG monomer with double bonds is 70-110°C.

[0019] In one preferred embodiment, the high-TG monomer with double bonds is one or more of styrene, isobornyl acrylate, and isobornyl methacrylate. Styrene is preferred from the perspective of adhesion and cost.

[0020] In one preferred embodiment, the methoxy polyethylene glycol methacrylate is EM3105.

[0021] The structural formula of the EM3105 is as follows:

[0022] In one preferred embodiment, the 2-hydroxyethyl methacrylate phosphate is PM1510.

[0023] The structural formula of PM1510 is:

[0024] The preparation method of the UV resin includes the following steps:

[0025] S1. Styrene, MMA, EM3105, GMA, HPA, PM151 and initiator are mixed in parts by weight to obtain mixed monomers;

[0026] S2. Slowly add the mixed monomers at 75-85℃, and keep warm for 2-3 hours after the addition is complete; then add the initiator and continue to keep warm for 3-5 hours.

[0027] S3. After the heat preservation is completed, add polyfunctional acrylate and triphenylphosphine, and heat to 100-110℃ and keep warm for 4-5 hours to react until the ester content is <2.

[0028] The synthesis route of the UV resin is as follows:

[0029]

[0030] The present invention also claims a UV resin dispersion obtained by dispersing UV resin in deionized water and removing the solvent.

[0031] The present invention also claims protection for a UV-curable PVD intermediate paint, comprising: 80-120 parts of UV resin dispersion, 10-20 parts of curing agent, 2-3 parts of initiator, 2-5 parts of additives, 3-5 parts of solvent and 20-40 parts of water.

[0032] In one preferred embodiment, the curing agent is an aliphatic polyisocyanate, preferably HDI.

[0033] In one preferred embodiment, the initiator is azobisisobutyronitrile.

[0034] In one preferred embodiment, the additive is a wetting agent, filler, or pigment.

[0035] In one preferred embodiment, the solvent is ethylene glycol butyl ether.

[0036] The present invention will be further explained below:

[0037] This invention achieves the grafting of acrylic resin and UV components by preparing a multifunctional acrylate. The acrylic resin provides adhesion to metal coatings, while the UV component offers the feasibility of UV curing crosslinking. Simultaneously, the different reactivity of the double bonds provides a multi-stage crosslinking technique, significantly improving adhesion. Furthermore, by grafting phosphate esters onto the acrylic resin, this invention further enhances the resin's adhesion and water resistance; and by grafting suitable hydrophilic components onto the resin backbone, the resin becomes water-based, reducing the VOC content of the coating system.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) In this invention, a multifunctional acrylate was synthesized. The difference in double bond activity in the multifunctional acrylate was utilized. The high-functionality double bonds provided a faster curing speed and better coating properties. The double bonds introduced by maleic anhydride had relatively low activity. In particular, the double bonds on the surface of the intermediate paint were difficult to crosslink due to oxygen inhibition. After the topcoat was sprayed, the double bonds in this part would crosslink with the double bonds in the topcoat, thereby providing excellent interlayer adhesion and ensuring that the coating could pass all the tests.

[0040] (2) The double bond density of the resin can be effectively adjusted by adjusting the amount of polyfunctional acrylate added, so as to obtain paint films with different crosslinking densities and meet different requirements for water resistance.

[0041] (3) Phosphate esters are used in the formulation of medium paint. In this invention, the adhesion promoter PM1510 is introduced into the molecular backbone by grafting, which effectively improves the water resistance. Detailed Implementation

[0042] Example 1

[0043] (1) Add 1 mol of pentaerythritol triacrylate and 1 mol of maleic anhydride to a three-necked flask equipped with a mechanical stirrer and a thermometer, slowly heat to 80°C, keep warm until the material is completely dissolved, then add 4.3 g of triphenylphosphine, slowly heat to 105°C, and continue the reaction until the ester content is <66 to obtain intermediate 1.

[0044] Example 2

[0045] (1) Add 1 mol of HPA and 1 mol of maleic anhydride to a three-necked flask equipped with a mechanical stirrer and a thermometer, slowly heat to 80°C, keep warm until the material is completely dissolved, then add 3.5 g of triphenylphosphine, slowly heat to 105°C, and continue the reaction until the ester content is <244 to obtain intermediate 2.

[0046] Example 3

[0047] (1) Add 1 mol pentaerythritol triacrylate and 1 mol butyric anhydride to a three-necked flask equipped with a mechanical stirrer and a thermometer, slowly heat to 80°C, keep warm until the material is completely dissolved, then add 4.3 g of triphenylphosphine, slowly heat to 105°C, and continue the reaction until the ester content is <66 to obtain intermediate 3.

[0048] Example 4

[0049] (1) Add 1 mol of dipentaerythritol pentaacrylate and 1 mol of maleic anhydride to a three-necked flask equipped with a mechanical stirrer and a thermometer, slowly heat to 80°C, keep warm until the material is completely dissolved, then add 4.3 g of triphenylphosphine, slowly heat to 105°C, and continue the reaction until the ester content is <40 to obtain intermediate 4.

[0050] Example 5

[0051] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat to 80°C;

[0052] (2) Add 120g styrene, 140g MMA, 30g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0053] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0054] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0055] (5) After the heat preservation is completed, add 600 g of intermediate (intermediate 1-4) and 3 g of triphenylphosphine and slowly heat to 105℃ and keep warm for 4 h to react until the ester content is <3;

[0056] (6) After the heat preservation is completed, 1100 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion 1-4 with a solid content of 50%.

[0057] Comparative Example 1

[0058] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0059] (2) Add 120g styrene, 130g MMA, 40g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0060] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0061] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0062] (5) After the heat preservation is completed, add 600g of intermediate 2, 3g of triphenylphosphine and 1100g of deionized water and disperse evenly. Extract the solvent to obtain a milky white dispersion 5 with a solid content of 50%.

[0063] Comparative Example 2

[0064] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0065] (2) Add 120g styrene, 140g MMA, 30g EM3105, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0066] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0067] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0068] (5) After the heat preservation is completed, add 600g of intermediate 2 and 3g of triphenylphosphine and slowly heat to 105℃ and keep warm for 4h to react until the ester content is <3;

[0069] (6) After the heat preservation is completed, 1100 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion with a solid content of 50%.

[0070] The above dispersion was used to prepare PVD intermediate paint. The formulation, application process, and performance tests are shown in Table 1.

[0071] Table 1. Formulation, Construction Techniques, and Performance Tests

[0072]

[0073]

[0074] Dispersion 1 passed all tests; Dispersion 2 failed due to its low crosslinking density, which made it difficult to resist water erosion, resulting in failures in water resistance, vibration abrasion resistance, and chemical resistance; Dispersion 3 failed all tests mainly because it only had double bonds grafted onto PETA, and the activity of these double bonds was indistinguishable, leading to poor interlayer adhesion between the intermediate and topcoats, manifested as topcoat peeling during high temperature and humidity and boiling water tests, which in turn affected chemical resistance and vibration abrasion resistance; Dispersion 4 had excessively high hardness due to the grafted dipentaerythritol pentaacrylate in intermediate 4, resulting in poor adhesion to the coating; Dispersion 5 failed because intermediate 2 did not graft onto the main chain of acrylic resin, resulting in uneven distribution of the UV resin phase and acrylic resin phase after the intermediate paint cured, leading to microphase separation, which manifested as a hazy appearance of the paint film. Due to microphase separation, the water resistance of the acrylic resin phase region in the intermediate paint film is extremely poor. This is reflected in the test results, which show that it failed the high temperature and high humidity test and the boiling water test, as well as the chemical resistance and vibration and abrasion resistance tests. In dispersion 6, the resin did not graft PM1510, resulting in poor adhesion between the resin and the coating. In formulation 7, the initial adhesion of the coating is OK because PM1510 is not grafted onto the molecular backbone. However, in the water resistance test, the small molecule PM1510 did not crosslink with the resin, resulting in poor water resistance and chemical resistance.

[0075] Comparative Example 3

[0076] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0077] (2) Add 120g styrene, 140g MMA, 30g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0078] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0079] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0080] (5) After the heat preservation is completed, add 300g of intermediate 1 and 3g of triphenylphosphine and slowly heat to 105℃ and keep warm for 4h to react until the ester content is <3;

[0081] (6) After the heat preservation is completed, 800 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion with a solid content of 50% 7.

[0082] Comparative Example 4

[0083] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0084] (2) Add 120g styrene, 140g MMA, 30g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0085] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0086] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0087] (5) After the heat preservation is completed, add 450g of intermediate 1 and 3g of triphenylphosphine and slowly heat to 105℃ and keep warm for 4h to react until the ester < 3;

[0088] (6) After the heat preservation is completed, 950 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion with a solid content of 50% 8.

[0089] Comparative Example 5

[0090] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0091] (2) Add 120g styrene, 140g MMA, 30g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0092] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0093] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0094] (5) After the heat preservation is completed, add 750 g of intermediate 1 and 3 g of triphenylphosphine and slowly heat to 105°C and keep warm for 4 h to react until the ester content is <3.

[0095] (6) After the heat preservation is completed, 1250 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion 9 with a solid content of 50%.

[0096] Comparative Example 6

[0097] (1) Add 480 g of butyl ester to a three-necked flask equipped with a mechanical stirrer and a thermometer, and slowly heat it to 80°C;

[0098] (2) Add 120g styrene, 140g MMA, 30g EM3105, 5g PM1510, 100g GMA, 100g HPA and 5g AIBN to the dropping container and disperse evenly until AIBN is completely dissolved.

[0099] (3) After the material in the three-necked flask is heated to 80°C, the monomer is added dropwise over 4 hours, and then kept warm for 3 hours after the addition is complete.

[0100] (4) After the heat preservation is completed, add 0.2 g of AIBN and 20 g of butyl ester for 10 min, and then keep warm for 4 h after the addition is completed;

[0101] (5) After the heat preservation is completed, add 900g of intermediate 1 and 3g of triphenylphosphine and slowly heat to 105℃ and keep warm for 4h to react until the ester content is <3;

[0102] (6) After the heat preservation is completed, 1400 grams of water is added for dispersion, and the solvent is extracted to obtain a micro-permeable dispersion 10 with a solid content of 50%.

[0103] The above dispersion was used to prepare PVD medium paint. The formulation, application process, and performance tests are shown in Table 2.

[0104] Table 2. Formulation, Construction Techniques, and Performance Tests

[0105]

[0106] The low content of intermediate 1 in dispersion 7 resulted in an excessively low crosslinking density, causing it to fail the tests for water resistance, chemical resistance, and vibration and abrasion resistance. Similarly, the excessively high content of intermediate 1 in dispersion 10 resulted in an excessively high crosslinking density, leading to poor adhesion to the coating and causing it to fail all tests. Therefore, the amount of intermediate 1 added should be 450-750 parts.

[0107] All references, patents, and patent applications cited in the foregoing are incorporated herein by reference in their entirety. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail. The foregoing description, provided to enable those skilled in the art to practice this disclosure protected by the claims, shall not be construed as a limitation on the scope of this disclosure, which is defined by the claims and all their equivalents.

Claims

1. A UV resin, characterized in that, The raw materials include 90-150 parts of a high-TG monomer with double bonds and 450-750 parts of a polyfunctional acrylate. The polyfunctional acrylate is prepared by the following method: a ring-opening reaction between a polyol acrylate and maleic anhydride at 100-110°C. The polyol acrylate is pentaerythritol triacrylate. The high-TG monomer with double bonds is one or more of styrene, isobornyl acrylate, and isobornyl methacrylate.

2. The UV resin according to claim 1, characterized in that, A catalyst is added to the ring-opening reaction, wherein the catalyst is triphenylphosphine, benzyltriethylammonium bromide, triethylamine or tetrabutylammonium bromide.

3. The UV resin according to claim 1, characterized in that, The UV resin comprises 90-150 parts of high TG monomer with double bonds, 335-410 parts of acrylate, 4-6 parts of phosphate ester, 450-750 parts of multifunctional acrylate, and 5-10 parts of catalyst.

4. The UV resin according to claim 1, characterized in that, The high-TG monomer with double bonds has a TG value of 70-110℃.

5. The UV resin according to claim 1, characterized in that, Its raw materials include 90-150 parts of high-TG monomers with double bonds, 120-140 parts of methyl methacrylate, 35-45 parts of methoxy polyethylene glycol methacrylate, 90-110 parts of glycidyl methacrylate, 90-110 parts of hydroxypropyl acrylate, 4-6 parts of 2-hydroxyethyl methacrylate phosphate, 450-750 parts of polyfunctional acrylates, and 5-10 parts of triphenylphosphine.

6. The method for preparing the UV resin according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Styrene, MMA, EM3105, GMA, HPA, PM151 and initiator are mixed in parts by weight to obtain mixed monomers; S2. Slowly add the mixed monomers at 75-85℃, and keep warm for 2-3 hours after the addition is complete; then add the initiator and continue to keep warm for 3-5 hours. S3. After the heat preservation is completed, add polyfunctional acrylate and triphenylphosphine, and heat to 100-110℃ and keep warm for 4-5 hours to react until the ester content is <2.

7. A UV resin dispersion, characterized in that, The UV resin dispersion is obtained by dispersing the UV resin as described in any one of claims 1-5 in deionized water and removing the solvent.

8. A UV-curable PVD intermediate paint, characterized in that, include: 80-120 parts of the UV resin dispersion as described in claim 7, 10-20 parts of curing agent, 2-3 parts of initiator, 2-5 parts of additives, 3-5 parts of solvent and 20-40 parts of water.

9. The UV-cured PVD intermediate paint according to claim 8, characterized in that, The curing agent is an aliphatic polyisocyanate; the initiator is azobisisobutyronitrile; and the solvent is ethylene glycol butyl ether.

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