A preparation method of photosensitive hexafunctional polyester acrylate

Abstract

The present invention discloses a method for preparing a photosensitive hexafunctional polyester acrylate. The method first reacts acryloyl chloride, oxalyl chloride, and tartaric acid to obtain an intermediate I having four terminal carboxyl groups and two active terminal double bonds. The intermediate I is then reacted with hydroxyethyl acrylate and butanediol diglycidyl ether under certain reaction conditions to obtain a final product. Through extensive experimental screening, the method optimizes the raw material composition, ratio, and process synthesis steps. The resulting hexafunctional polyester acrylate offers high cost-effectiveness, good stability, and excellent overall properties such as hardness, flexibility, and gloss.

Description

Technical Field

[0001] The present invention relates to an oligomer for photosensitive coatings, in particular to a preparation method of a novel photosensitive hexafunctional polyester acrylate, belonging to the technical field of polymer materials. Background Art

[0002] UV curing is a material surface treatment technology that emerged in the 1960s. It involves adding a photoinitiator (or photosensitizer) to a specially formulated system (commonly referred to as a photocuring system). The initiator absorbs the high-intensity UV light generated by the UV curing equipment, generating reactive free radicals or cations. This in turn triggers polymerization, cross-linking, and grafting reactions, transforming the material from a liquid into a solid over a period of time. Existing UV curing systems are primarily categorized as free radical and cationic. The former primarily involves the photoinitiator being excited by UV light to generate reactive free radicals, which then initiate polymerization and cross-linking reactions on active double bonds within the system. The latter, on the other hand, involves a cationic photoinitiator absorbing UV light to generate a strong proton acid, which catalyzes addition polymerization reactions on oxygen heterocycles. Currently, free radical UV curing systems have a much wider application range than cationic systems due to their economical applicability. Consequently, free radical UV curing prepolymers, as the most amenable to molecular structure design, have attracted considerable attention.

[0003] The present invention synthesizes a polyester acrylate containing six effective ends through a creative design scheme, thereby obtaining a novel hexafunctional photosensitive prepolymer with excellent comprehensive performance. Summary of the Invention

[0004] Purpose of the Invention: This invention provides a novel method for synthesizing polyester acrylates. Through extensive experimental screening, the present invention selects acryloyl chloride, oxalyl chloride, and tartaric acid, and, under specific reaction conditions, produces an intermediate I with four terminal carboxyl groups and two reactive terminal double bonds. This intermediate I is then reacted with hydroxyethyl acrylate and butanediol diglycidyl ether to produce a novel photosensitive hexafunctional polyester acrylate. The photosensitive hexafunctional polyester acrylate provided by this invention can be widely used in various photocurable coating systems requiring high reactivity and low viscosity.

[0005] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a novel photosensitive hexafunctional polyester acrylate comprises the following steps:

[0007] (1) First, acryloyl chloride, tartaric acid, and oxalyl chloride are selected and reacted under certain conditions to prepare an intermediate I having four terminal carboxyl groups and two active terminal double bonds;

[0008] (2) The intermediate I is then reacted with hydroxyethyl acrylate and butanediol diglycidyl ether under certain conditions to prepare a photosensitive hexafunctional polyester acrylate.

[0009] The method for preparing a novel photosensitive hexafunctional polyester acrylate as a preferred embodiment comprises the following steps:

[0010] (1) First, 5-20 parts by mass of acryloyl chloride, 15-30 parts by mass of tartaric acid, and 5-20 parts by mass of oxalyl chloride are selected and reacted under certain conditions to prepare an intermediate I having four terminal carboxyl groups and two active terminal double bonds;

[0011] (2) The intermediate I is then reacted with 20-45 parts by mass of hydroxyethyl acrylate and 0-3 parts by mass of butanediol diglycidyl ether under certain conditions to prepare a photosensitive hexafunctional polyester acrylate.

[0012] As a preferred embodiment, the preparation method of the novel photosensitive hexafunctional polyester acrylate, the specific steps of step (1) are: dissolving acryloyl chloride and oxalyl chloride in 7 parts by mass of toluene, slowly adding dropwise to 14 parts by mass of toluene miscible with tartaric acid, while using a micro-vacuum of -0.001 to -0.01 MPa to remove the acid mist generated by the reaction, the dropping time is 1 to 8 hours, and after the dropwise addition is completed, the reaction is continued under vacuum, the reaction temperature is controlled between -10°C and 40°C, the reaction time is 5 to 12 hours, and after the reaction is completed, the temperature is lowered to obtain an intermediate I with four terminal carboxyl groups and two active terminal double bonds;

[0013] As a preferred embodiment, the preparation method of the novel photosensitive hexafunctional polyester acrylate, the specific steps of step (2) are: adding hydroxyethyl acrylate to intermediate I, then adding 0-0.5 parts by mass of hypophosphorous acid as an antioxidant, 0-0.5 parts by mass of hydroquinone as an inhibitor and 0-1 parts by mass of p-toluenesulfonic acid as a catalyst, controlling the reaction time to 5 to 10 hours and the reaction temperature to 90°C to 150°C; when the acid value is lower than 10 mgKOH / g, cooling to below 80°C, adding butanediol diglycidyl ether and 0-0.5 parts by mass of triphenylphosphine as a catalyst, controlling the reaction time to 1-3 hours and the reaction temperature to 90-120°C; after the reaction is completed, opening a vacuum of -0.1 MPa and desolventizing for 1.5 to 4 hours to obtain the finished photosensitive hexafunctional polyester acrylate.

[0014] The key point of the present invention is that the synthesis of intermediate I requires strict control of the vacuum environment, material ratio, dropwise addition time, reaction temperature and reaction time. Since tartaric acid and oxalyl chloride are both bifunctional raw materials, if the appropriate reaction conditions are not strictly controlled, an unpredictable chain multifunctional structure will appear. At this time, the viscosity of the resin will increase sharply, and a final product with relatively excellent comprehensive performance cannot be obtained. However, the butanediol diglycidyl ether used therein can effectively reduce the acid value of the final product, thereby ensuring good storage and use stability of the target product.

[0015] The key point of the present invention is that the vacuum environment needs to be strictly controlled during the synthesis of intermediate I. Since the reaction has a certain reversible tendency, when a certain vacuum environment is controlled, the solvent in the system can be prevented from being removed while the hydrochloric acid mist generated by the forward reaction can be removed in time, thereby synthesizing an intermediate I with four terminal carboxyl groups and two active terminal double bonds.

[0016] Beneficial Effects: Through extensive experimental screening, the present invention selects acryloyl chloride, oxalyl chloride, and tartaric acid under certain reaction conditions to obtain an intermediate I with four terminal carboxyl groups and two active terminal double bonds. This intermediate I reacts with hydroxyethyl acrylate and butanediol diglycidyl ether to ultimately produce a novel photosensitive hexafunctional polyester acrylate. The photosensitive hexafunctional polyester acrylate provided by the present invention can be widely used in various photocurable coating systems requiring high reactivity and low viscosity. Experimental results also show that the hexafunctional polyester acrylate provided by the present invention has comprehensive properties such as good stability, low viscosity, fast curing speed, high hardness, and good flexibility, which can address the shortcomings of the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a reaction flow chart of the present invention. DETAILED DESCRIPTION

[0018] Example 1

[0019] A method for preparing a novel photosensitive hexafunctional polyester acrylate comprises the following steps:

[0020] (1) 13 parts by mass of acryloyl chloride and 9.1 parts by mass of oxalyl chloride were dissolved in 7 parts by mass of toluene and slowly added dropwise to 14 parts by mass of toluene in which 21.6 parts by mass of tartaric acid was dissolved. A slight vacuum of -0.008 MPa was used to remove the acid mist generated by the reaction. The addition time was 4 hours. After the addition was completed, the reaction was continued under vacuum. The reaction temperature was controlled at -5°C and the reaction time was 10 hours. After the reaction was completed, intermediate I was obtained. The reaction yield was about 94%, and intermediate I 1H-NMR test showed that the chemical shift around 2.0, which represents the displacement of the hydrogen atom on the hydroxyl group of tartaric acid, disappeared. At the same time, the peak area ratio of the chemical shift around 11.0, which represents the hydrogen atom of the carboxylic acid on intermediate I, and the chemical shift around 6.05, which represents the hydrogen atom on the tertiary carbon in the C=C double bond, was approximately 2:1. This result indicated that intermediate I had been successfully synthesized.

[0021]

[0022] (2) The intermediate I product of step (1) was mixed evenly with 33.5 parts by mass of hydroxyethyl acrylate, and then 0.1 parts by mass of hypophosphorous acid as an antioxidant, 0.1 parts by mass of hydroquinone as an inhibitor, and 0.5 parts by mass of p-toluenesulfonic acid as a catalyst were added. The reaction time was controlled to 9 hours, and the reaction temperature was 118°C. When the acid value was lower than 10 mgKOH / g, the temperature was lowered to below 80°C. 1 part by mass of butanediol diglycidyl ether and 0.1 parts by mass of triphenylphosphine as a catalyst were added. The reaction time was controlled to 2.5 hours, and the reaction temperature was 115°C. After the reaction was completed, a vacuum of -0.1 MPa was opened, and the solvent was removed for 2 hours to obtain a finished product of a novel photosensitive hexafunctional polyester acrylate. The reaction yield was about 92%, and the final product was 1 H-NMR test showed that the peak area ratio of the chemical shift of the hydrogen atom on the tertiary carbon in the C=C double bond of the final product at about 6.05 and the chemical shift of the hydrogen atom on the tertiary carbon atom at the original tartaric acid position at about 6.02 was about 3:2. This result indicated that the final product had been successfully synthesized.

[0023]

[0024] Example 2

[0025] A method for preparing a novel photosensitive hexafunctional polyester acrylate comprises the following steps:

[0026] (1) 13 parts by mass of acryloyl chloride and 7 parts by mass of oxalyl chloride were dissolved in 7 parts by mass of toluene and slowly added dropwise to 14 parts by mass of toluene in which 21.6 parts by mass of tartaric acid was dissolved. A slight vacuum of -0.008 MPa was used to remove the acid mist generated by the reaction. The addition time was 4 hours. After the addition was completed, the reaction was continued under vacuum. The reaction temperature was controlled at 0°C and the reaction time was 10 hours. After the reaction was completed, intermediate I was obtained. The reaction yield was about 49%. Intermediate I 1 H-NMR testing showed that the peak area ratio of the chemical shift of approximately 11.0 for the hydrogen atom of the carboxylic acid on intermediate I and the chemical shift of approximately 6.05 for the hydrogen atom on the tertiary carbon in the C=C double bond was much greater than 2:1, indicating that a relatively obvious chain structure had been formed. This suggests that the experimental conditions of reactant dosage and reaction temperature for synthesizing intermediate I in this step were unreasonable, which had a significant impact on the reaction.

[0027] (2) The intermediate I reaction product of step (1) was mixed evenly with 35.3 parts by mass of hydroxyethyl acrylate, and then 0.1 parts by mass of hypophosphorous acid as an antioxidant, 0.1 parts by mass of hydroquinone as a polymerization inhibitor, and 0.8 parts by mass of p-toluenesulfonic acid as a catalyst were added. The reaction time was controlled to 9 hours, and the reaction temperature was 125°C. When the acid value was lower than 10 mgKOH / g, the temperature was lowered to below 80°C. 1 part by mass of butanediol diglycidyl ether and 0.1 parts by mass of triphenylphosphine as a catalyst were added. The reaction time was controlled to 2.5 hours, and the reaction temperature was 120°C. After the reaction was completed, a vacuum of -0.1 MPa was opened and the solvent was removed for 2 hours to obtain a finished product of a novel photosensitive hexafunctional polyester acrylate. The reaction yield was approximately 48%.

[0028] Example 3

[0029] A method for preparing a novel photosensitive hexafunctional polyester acrylate comprises the following steps:

[0030] (1) 13 parts by mass of acryloyl chloride and 9.1 parts by mass of oxalyl chloride were dissolved in 7 parts by mass of toluene and slowly added dropwise to 14 parts by mass of toluene in which 21.6 parts by mass of tartaric acid was dissolved. A slight vacuum of -0.004 MPa was used to remove the acid mist generated by the reaction. The addition time was 4 hours. After the addition was completed, the reaction was continued under vacuum. The reaction temperature was controlled at -5°C and the reaction time was 10 hours. After the reaction was completed, intermediate I was obtained. The reaction yield was about 67%, and intermediate I 1 H-NMR test, the chemical shift near 2.0 that represents hydrogen atom displacement on hydroxyl group on tartaric acid does not disappear completely, illustrates that the vacuum degree of this step is very large on reaction impact.The intermediate I synthesized under this vacuum degree condition does not reach design standard completely.When the emphasis of this step is synthetic intermediate I, need to strictly control vacuum environment, because this reaction has certain reversible tendency, when controlling the certain best vacuum environment, can avoid solvent in system from being taken off while the hydrochloric acid mist produced by positive reaction is promptly deviated from, improve synthesis efficiency.

[0031] (2) The intermediate I reaction product of step (1) was uniformly mixed with 33.5 parts by mass of hydroxyethyl acrylate, and then 0.1 parts by mass of hypophosphorous acid as an antioxidant, 0.1 parts by mass of hydroquinone as a polymerization inhibitor, and 0.5 parts by mass of p-toluenesulfonic acid as a catalyst were added. The reaction time was controlled to 7 hours, and the reaction temperature was 125°C. When the acid value was lower than 10 mgKOH / g, the temperature was lowered to below 80°C, and 1 part by mass of butanediol diglycidyl ether and 0.1 parts by mass of triphenylphosphine as a catalyst were added. The reaction time was controlled to 2 hours, and the reaction temperature was 120°C. After the reaction was completed, a vacuum of -0.1 MPa was opened and the solvent was removed for 2 hours to obtain a finished product of a novel photosensitive hexafunctional polyester acrylate. The reaction yield was about 66%.

[0032] Example 4 Performance Test

[0033] The performance of the photosensitive hexafunctional photocurable resin obtained in Example 1 was measured, and the specific experimental results are shown in Table 1 below.

[0034] Table 1 Performance test results

[0035]

[0036] Note: The curing speed in the table is directly on a UV curing machine at 80mW / cm 2 The hardness and gloss tests refer to GB / T13448-2006 standard, and the flexibility test refers to GB / T1731 standard.

[0037] The above experimental results show that the novel photosensitive hexafunctional polyester acrylate prepared in Example 1 of the present invention has the characteristics of good stability and excellent comprehensive performance.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a photosensitive hexafunctional polyester acrylate, characterized in that: The following steps are involved: Step (1): dissolve acryloyl chloride and oxalyl chloride in 7 parts by mass of toluene, and slowly add dropwise to 14 parts by mass of toluene miscible with tartaric acid, while using a micro-vacuum of -0.001 to -0.01 MPa to remove the acid mist generated by the reaction, the dropping time is 1 to 8 hours, and after the dropwise addition is completed, the reaction is continued under vacuum, the reaction temperature is controlled between -10°C and 40°C, and the reaction time is 5 to 12 hours. After the reaction is completed, the temperature is lowered to obtain an intermediate I with four terminal carboxyl groups and two active terminal double bonds, the reaction formula of which is as follows: ； Step (2): Add hydroxyethyl acrylate to the intermediate I, and then add 0-0.5 parts by mass of hypophosphorous acid as an antioxidant, 0-0.5 parts by mass of hydroquinone as an inhibitor and 0-1 parts by mass of p-toluenesulfonic acid as a catalyst, control the reaction time to 5 to 10 hours, and the reaction temperature to 90°C to 150°C. When the acid value is lower than 10 mgKOH / g, cool it to below 80°C, add butanediol diglycidyl ether and 0-0.5 parts by mass of triphenylphosphine as a catalyst, control the reaction time to 1-3 hours, and the reaction temperature to 90-120°C. After the reaction is completed, open the vacuum to -0.1MPa and desolventize for 1.5 to 4 hours to obtain the finished product photosensitive hexafunctional polyester acrylate, the reaction formula of which is as follows: 。 2. The method for preparing the photosensitive hexafunctional polyester acrylate according to claim 1, wherein: The following steps are included Step (1): 13 parts by mass of acryloyl chloride and 9.1 parts by mass of oxalyl chloride are dissolved in 7 parts by mass of toluene, and the mixture is slowly added dropwise to 14 parts by mass of toluene in which 21.6 parts by mass of tartaric acid is dissolved. While adding the mixture dropwise, a slight vacuum of -0.01 MPa is used to remove the acid mist generated by the reaction. The addition time is 4 hours. After the addition is completed, the reaction is continued under vacuum, the reaction temperature is controlled at -5°C, and the reaction time is 10 hours. After the reaction is completed, intermediate I is obtained. Step (2): The intermediate I is mixed evenly with 33.5 parts by mass of hydroxyethyl acrylate, and then 0.1 parts by mass of hypophosphorous acid as an antioxidant, 0.1 parts by mass of hydroquinone as an inhibitor and 0.5 parts by mass of p-toluenesulfonic acid as a catalyst are added. The reaction time is controlled to be 9 hours and the reaction temperature is 118°C. When the acid value is lower than 10 mgKOH / g, the temperature is lowered to below 80°C. 1 part by mass of butanediol diglycidyl ether and 0.1 parts by mass of triphenylphosphine as a catalyst are added. The reaction time is controlled to be 2.5 hours and the reaction temperature is 115°C. After the reaction is completed, a vacuum of -0.1 MPa is opened and desolventizing is carried out for 2 hours to obtain a finished product of photosensitive hexafunctional polyester acrylate.

3. Use of the photosensitive hexafunctional polyester acrylate prepared by the preparation method according to claim 1 or 2 in the preparation of oligomers for photosensitive coatings.

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