An ultrahigh-temperature-resistant low-yellowing uv polyester acrylate and a preparation method thereof

Abstract

The application discloses a kind of superhigh temperature resistant low yellowing UV polyester acrylate and preparation method thereof, belong to the field of photocuring oligomer.A kind of superhigh temperature resistant low yellowing UV polyester acrylate preparation method includes: step 1: yellowing resistant aromatic dibasic acid, alicyclic dibasic alcohol, solvent, catalyst and antioxidant are mixed, and the acid value is ≤50mgKOH / g in 160-180 ℃ reflux reaction;Step 2: temperature is increased to 200-230 ℃ negative pressure reaction until the acid value is ≤1mgKOH / g, hydroxyl value is 30-80mgKOH / g;Step 3: (methyl) acrylic acid is added, and the product is obtained after being reacted at 85-95 ℃ reflux and water separation, and then being heated to 118 ℃ until the acid value is <12mgKOH / g, and dilute monomer is added after desolventizing.The product obtained by the application can withstand 250 ℃ / 45min, has superlow yellowing, high Tg and excellent adhesion, solves the technical problem that existing products cannot be resistant to high temperature and low yellowing, and is suitable for UV curing coating in high temperature environment.

Description

Technical Field

[0001] This invention relates to the field of photocurable oligomer technology, and in particular to a UV-resistant, high-temperature-resistant, low-yellowing UV-curable polyester acrylate and its preparation method. Background Technology

[0002] UV polyester acrylate, as the core matrix material of the photocurable resin system, has been widely used in many fields such as electronic component packaging, automotive parts coating, optical material protection, and high-end equipment surface protection due to its outstanding advantages such as rapid curing under UV irradiation, solvent-free emission, strong adhesion of cured coating, and excellent mechanical properties. It has become one of the resin types with the largest usage and widest application in the photocurable coating industry.

[0003] As industrial manufacturing develops towards high-end and refined products, the requirements for the application environment of UV-cured coatings in the aforementioned application fields are constantly increasing. In particular, in scenarios such as the periphery of automotive engines, high-temperature electronic equipment, LED packaging, and high-temperature areas of photovoltaic modules, the coatings need to not only have the efficient construction characteristics of rapid UV curing, but also be able to withstand short-term high temperatures above 200°C, while maintaining excellent low yellowing properties to avoid yellowing or discoloration of the coating due to high temperatures or long-term use, which would affect the appearance and performance of the product.

[0004] However, existing UV polyester acrylate products on the market generally suffer from a core industry pain point—the inability to simultaneously achieve high-temperature resistance and low yellowing performance, making it difficult to meet the stringent requirements of high-temperature environments. Specifically, in current technologies, to improve the high-temperature resistance of UV polyester acrylates, methods such as introducing aromatic structures and increasing resin crosslinking density are commonly used. While these methods can improve the resin's short-term high-temperature resistance to around 200°C, aromatic structures are highly susceptible to degradation and discoloration under high temperatures or photo-oxidation, leading to rapid yellowing of the coating and severely affecting the product's appearance and weather resistance. Conversely, to achieve low yellowing, existing technologies often employ a fully aliphatic structure design. Although this effectively suppresses yellowing, the poor thermal stability of aliphatic structures significantly reduces the resin's short-term high-temperature resistance, typically only able to withstand temperatures below 150°C. Above this temperature, problems such as coating softening, embrittlement, and performance degradation occur, making it unsuitable for high-temperature applications.

[0005] Therefore, the industry urgently needs a UV polyester acrylate that can simultaneously achieve short-term high-temperature resistance at 250℃, low yellowing, and rapid UV curing performance. This would break through the technical bottleneck of existing products where "high temperature resistance and low yellowing cannot be achieved simultaneously," fill the market gap for high-performance resins for UV-cured coatings under high-temperature environments, and meet the practical application needs of high-end fields such as electronics, automobiles, and optics. Summary of the Invention

[0006] This invention aims to solve the technical problem that existing UV-resistant polyester acrylates cannot simultaneously achieve high temperature resistance and low yellowing performance, and provides an ultra-high temperature resistant, low yellowing UV-resistant polyester acrylate and its preparation method.

[0007] The technical solution of the present invention is as follows: A UV-resistant polyester acrylate with ultra-high temperature resistance and low yellowing, the structural formula of which is shown below: Wherein, R1 is an aromatic alkyl group and R2 is an alicyclic alkyl group.

[0008] The present invention also provides a method for preparing the above-mentioned ultra-high temperature resistant, low yellowing UV-resistant polyester acrylate, comprising the following steps: Step 1: Add the yellowing-resistant aromatic dicarboxylic acid and alicyclic diol to the reaction vessel, then add the solvent, catalyst and antioxidant, slowly start stirring, heat to 160-180℃, reflux at normal pressure for 4-6 hours, and remove water at the same time until the acid value is ≤50mgKOH / g.

[0009] Step 2: Heat to 200-230℃ and react for 4-6 hours under a negative pressure of -0.08 to -0.095MPa until the final acid value is ≤1mgKOH / g and the hydroxyl value ranges from 30-80mgKOH / g. Then cool down to 110℃, mix with the solvent used in Step 3, and then cool down to 90℃.

[0010] Step 3: After adding the solvent described in Step 2, add the catalyst, antioxidant, mixed polymerization inhibitor and (meth)acrylic acid. Introduce air into the bottom of the reactor, keep the temperature at 85-95℃, and reflux for 2-3 hours. Separate the water generated in the reaction through a water separator, then raise the temperature to 118℃ and react for 3-5 hours until the acid value is less than 12mgKOH / g. Cool down to 90℃ and remove the solvent under a negative pressure of -0.09MPa or higher. After solvent removal, the acid value is <10mgKOH / g. Add the diluent monomer and mix evenly. Cool down to 70℃ and discharge to obtain ultra-high temperature resistant, low yellowing UV-resistant polyester acrylate.

[0011] In the above preparation method, the mass ratio of each raw material is as follows: yellowing resistant aromatic dicarboxylic acid: alicyclic diol: step 1 solvent: step 1 catalyst: step 1 antioxidant: step 3 solvent: step 3 catalyst: step 3 antioxidant: step 3 mixed polymerization inhibitor: (meth)acrylic acid: diluent monomer = (300-400): (350-600): (90-150): (0.3-2.0): (0.6-3.0): (150-300): (3-12): (2-6): (0.8-4.0): (35-90): (200-400).

[0012] Preferably, the yellowing-resistant aromatic dicarboxylic acid in step 1 is one or any combination of 2,3,5,6-tetramethylterephthalic acid and terephthalic acid.

[0013] Preferably, the alicyclic diol in step 1 is one or any combination of hydrogenated bisphenol A diol (HBPA) and 1,4-cyclohexanediethanol (CHDM).

[0014] Preferably, the solvent in step 1 is xylene.

[0015] Preferably, the catalyst in step 1 is tetrabutyl titanate.

[0016] Preferably, the antioxidant in step 1 is one or more of antioxidant 1010 and antioxidant 168, or any combination thereof.

[0017] Preferably, the solvent in step 3 is toluene.

[0018] Preferably, the catalyst in step 3 is p-toluenesulfonic acid.

[0019] Preferably, the antioxidant in step 3 is one or more of hypophosphite and antioxidant 1010, or any combination thereof.

[0020] Preferably, the mixed polymerization inhibitor in step 3 is one or more of p-hydroxyanisole (MEHQ) and piperidinol oxide (H-TEMPO) in any combination.

[0021] Preferably, the (meth)acrylic acid in step 3 is one or more of acrylic acid and methacrylic acid, or any combination thereof.

[0022] Preferably, the diluent monomer in step 3 is one or more of the following: tri(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), tricyclodecanediethanol diacrylate (DCPDA), 1,4-cyclohexanediethanol diacrylate (CHDMDA), and isobornyl acrylate (IBOA).

[0023] The beneficial effects of this invention are: 1. This invention addresses the industry challenge of simultaneously achieving high-temperature resistance and low yellowing: It utilizes a polycondensation process between a yellowing-resistant aromatic diacid (such as 2,3,5,6-tetramethylterephthalic acid) and an alicyclic diol (such as HBPA or CHDM). The yellowing-resistant aromatic diacid provides an excellent high-temperature resistant framework, while the introduction of the alicyclic diol effectively breaks the continuous conjugated structure of the aromatic ring, significantly reducing the possibility of chromogenic groups forming at high temperatures, thus achieving ultra-low yellowing. Furthermore, due to the low shrinkage characteristics of the alicyclic raw materials, the resulting product exhibits excellent adhesion.

[0024] 2. Superior overall performance: The UV polyester acrylate prepared by this invention can withstand short-term ultra-high temperature of 250℃ / 45min, has an ultra-low yellowing value (ΔE value is significantly lower than that of commercially available products), a high glass transition temperature (Tg) and excellent adhesion, which can meet the stringent requirements of high-end application fields.

[0025] 3. Controllable preparation process, suitable for industrial production: This invention uses acid value titration and Fourier transform infrared spectroscopy to determine the reaction endpoint, resulting in a clear process route and well-defined parameters, making it easy to implement in industrial production. Furthermore, the addition of high-temperature resistant monomers for thinning effectively reduces the application viscosity, making the product easy to apply and possessing good processing applicability.

[0026] 4. Filling a market gap: This invention breaks through the technical bottleneck of existing products that cannot simultaneously achieve high temperature resistance and low yellowing, and fills the market gap for high-performance resins for UV-cured coatings under high temperature environments. It has broad application prospects and strong market competitiveness in high-end fields such as electronics, automobiles, and optics. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the ultra-high temperature resistant, low yellowing UV-resistant polyester acrylate of the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0030] In the following embodiments, all raw materials used are commercially available industrial products.

[0031] Example 1; Step 1: Add 88.90g of 2,3,5,6-tetramethylterephthalic acid, 265.81g of terephthalic acid, 360.57g of hydrogenated bisphenol A glycol (HBPA), and 144.21g of 1,4-cyclohexanediethanol (CHDM) to a reaction vessel, then add 129g of xylene, 1.0g of tetrabutyl titanate, and 1.25g of antioxidant 1010. Slowly start stirring, raise the temperature to 160-180℃, and reflux under normal pressure for 4-6 hours, while separating water, until the acid value is ≤50mgKOH / g.

[0032] Step 2: Heat to 200-230℃ and react for 4-6 hours under a negative pressure of -0.08 to -0.095MPa. The final acid value is ≤1mgKOH / g and the hydroxyl value ranges from 72 to 78mgKOH / g. Cool down to 110℃, mix with 233g of toluene, and then cool down to 90℃.

[0033] Step 3: After adding toluene, add 4g p-toluenesulfonic acid, 3.5g hypophosphorous acid, 0.78g MEHQ, 1.2g H-TEMPO, and 86.09g methacrylic acid. Introduce air into the bottom of the reactor and maintain the temperature at 85-95℃. Reflux for 2-3 hours. Separate the water generated by the reaction using a water separator. Then raise the temperature to 118℃ and react for 3-5 hours until the acid value is less than 12mgKOH / g. Cool down to 90℃ and remove the solvent under a negative pressure of -0.09MPa or higher. After solvent removal, the acid value is <10mgKOH / g. Add 250g tricyclodecanediethanol diacrylate (DCPDA), mix thoroughly, and then cool down to 70℃ to discharge the product.

[0034] Example 2; Step 1: Same as in Example 1.

[0035] Step 2: Same as in Example 1.

[0036] Step 3: After adding toluene, add 4g p-toluenesulfonic acid, 3.5g hypophosphite, 0.78g MEHQ, 1.2g H-TEMPO, and 72.02g acrylic acid. The remaining operations are the same as in Example 1, and the final product is obtained.

[0037] Example 3; Step 1: Same as in Example 1.

[0038] Step 2: Same as in Example 1.

[0039] Step 3: After adding toluene, add 4g p-toluenesulfonic acid, 3.5g hypophosphite, 0.78g MEHQ, 1.2g H-TEMPO, and 86.09g methacrylic acid. The remaining operations are the same as in Example 1, except that after solvent removal, add 250g tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA) and mix well to obtain the product.

[0040] Example 4; Step 1: Same as in Example 1.

[0041] Step 2: Same as in Example 1.

[0042] Step 3: After adding toluene, add 4g p-toluenesulfonic acid, 3.5g hypophosphite, 0.78g MEHQ, 1.2g H-TEMPO, and 72.02g acrylic acid. The remaining operations are the same as in Example 3. After solvent removal, add 250g tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA) and mix well to obtain the product.

[0043] Example 5; Step 1: Same as in Example 1.

[0044] Step 2: Same as in Example 1.

[0045] Step 3: After adding toluene, add 4g of p-toluenesulfonic acid, 3.5g of hypophosphoric acid, 0.78g of MEHQ, 1.2g of H-TEMPO, and 86.09g of methacrylic acid. The remaining operations are the same as in Example 1, except that after solvent removal, add 250g of 1,4-cyclohexanediethanol diacrylate (CHDMDA) and mix well to obtain the product.

[0046] Example 6; Step 1: Same as in Example 1.

[0047] Step 2: Same as in Example 1.

[0048] Step 3: After adding toluene, add 4g p-toluenesulfonic acid, 3.5g hypophosphite, 0.78g MEHQ, 1.2g H-TEMPO, and 72.02g acrylic acid. The remaining operations are the same as in Example 5. After solvent removal, add 250g 1,4-cyclohexanediethanol diacrylate (CHDMDA) and mix well to obtain the product.

[0049] Comparative Example 1; A commercially available product, Jiangmen Hengzhiguang 73608C, was selected as a comparative example. This product is a resin with good performance in terms of high temperature resistance and yellowing resistance on the market.

[0050] Performance testing: The resins obtained in Examples 1-6 and Comparative Example 1 were mixed evenly at a ratio of 20g resin to 1g photoinitiator MBF, and after being fully dissolved, defoaming treatment was performed. The mixture was then applied to the same white ceramic tile using a 25μm coater and UV cured at a curing energy of 1000mj / cm². The cured coating was then baked in an oven at 250°C for 45 minutes.

[0051] The test results are as follows: 1. Yellowing value (△E): Measured directly using a spectrophotometer.

[0052] 2. Leveling properties: Visual inspection.

[0053] 3. Surface dryness: finger touch test.

[0054] The test results are listed in Table 1: Table 1 As shown in Table 1 and the above description, under similar leveling and surface drying properties, the UV-resistant polyester acrylates prepared in Examples 1-6 of this invention exhibit significantly better yellowing resistance than commercially available products (Comparative Example 1), with Example 3 showing the best yellowing resistance. This indicates that this invention successfully achieves a balance between ultra-high temperature resistance and low yellowing performance, demonstrating significant industrial application value.

[0055] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A UV-resistant polyester acrylate with ultra-high temperature resistance and low yellowing, characterized in that, It has the following structural formula: In the structural formula, R1 is an aromatic alkyl group and R2 is an alicyclic alkyl group.

2. A method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate, characterized in that, Includes the following steps: Step 1: Add the yellowing-resistant aromatic dicarboxylic acid and alicyclic diol to the reaction vessel, then add the solvent, catalyst and antioxidant, slowly start stirring, heat to 160-180℃, reflux at normal pressure for 4-6 hours, and remove water at the same time until the acid value is ≤50mgKOH / g. Step 2: Heat to 200-230℃ and react under a negative pressure of -0.08 to -0.095MPa for 4-6 hours until the final acid value is ≤1mgKOH / g and the hydroxyl value ranges from 30-80mgKOH / g. Then cool down to 110℃, mix with the solvent used in Step 3, and then cool down to 90℃. Step 3: After adding the solvent described in Step 2, add the catalyst, antioxidant, mixed polymerization inhibitor and (meth)acrylic acid. Introduce air into the bottom of the reactor, keep the temperature at 85-95℃, and reflux for 2-3 hours. Separate the water generated in the reaction through a water separator, then raise the temperature to 118℃ and react for 3-5 hours until the acid value is less than 12mgKOH / g. Cool down to 90℃ and remove the solvent under a negative pressure of -0.09MPa or higher. After solvent removal, the acid value is <10mgKOH / g. Add the diluent monomer and mix evenly. Cool down to 70℃ and discharge to obtain ultra-high temperature resistant, low yellowing UV-resistant polyester acrylate. The mass ratio of the yellowing-resistant aromatic dicarboxylic acid, alicyclic diol, solvent of step 1, catalyst of step 1, antioxidant of step 1, solvent of step 3, catalyst of step 3, antioxidant of step 3, mixed polymerization inhibitor of step 3, (meth)acrylic acid, and diluent monomer is: (300-400): (350-600): (90-150): (0.3-2.0): (0.6-3.0): (150-300): (3-12): (2-6): (0.8-4.0): (35-90): (200-400).

3. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The yellowing-resistant aromatic dicarboxylic acid in step 1 is one or any combination of 2,3,5,6-tetramethylterephthalic acid and terephthalic acid.

4. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The alicyclic diol in step 1 is one or any combination of hydrogenated bisphenol A diol and 1,4-cyclohexanediethanol.

5. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The catalyst in step 1 is tetrabutyl titanate.

6. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The antioxidant in step 1 is one or more of antioxidant 1010 and antioxidant 168, or any combination thereof.

7. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The catalyst in step 3 is p-toluenesulfonic acid.

8. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The antioxidant in step 3 is one or more of hypophosphite and antioxidant 1010, or any combination thereof.

9. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The mixed polymerization inhibitor in step 3 is one or more of p-hydroxyanisole and piperidinol oxide, or any combination thereof.

10. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The (meth)acrylic acid in step 3 is one or more of acrylic acid and methacrylic acid, or any combination thereof.

11. The method for preparing a UV-resistant, ultra-high temperature resistant, low-yellowing polyester acrylate according to claim 2, characterized in that, The diluent monomer in step 3 is one or more of the following: tri(2-hydroxyethyl) isocyanurate triacrylate, tricyclodecanediethanol diacrylate (DCPDA), 1,4-cyclohexanediethanol diacrylate (CHDMDA), and isobornyl acrylate (IBOA).

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