Preparation method of modified polyester acrylate resin with good leveling property

Abstract

The invention discloses a preparation method of modified polyester acrylate resin with excellent leveling property, which comprises the following steps: firstly, reacting organic dihydric alcohol, trihydric alcohol and tetrahydric alcohol with organic anhydride or organic monobasic acid and binary acid in different proportions to obtain a hydroxyl-terminated intermediate A; carrying out esterification reaction on the intermediate A and an acrylic monomer, removing the solvent to obtain a semi-finished product B, and reducing the acid value of the semi-finished product B by using an organic compound containing an epoxy group to obtain a finished product C; a coating film of the modified polyester acrylate resin provided by the invention has good dryness, good flexibility and excellent leveling property, and a coating layer of the modified polyester acrylate resin has no shrinkage cavity phenomenon of common polyester acrylate resin.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable resins, and in particular to a method for preparing a modified polyester acrylate resin having good leveling properties. Background Art

[0002] UV curing technology was first researched and commercialized by a US 3D company. It is the most mature technology with the widest application field.

[0003] Photocuring refers to the curing process of monomers and oligomers under light induction, which is generally used in the film-forming process. Its technical principle is to make liquid photocurable resins and other photosensitive materials undergo high-speed polymerization through irradiation with ultraviolet light or visible light of a certain wavelength, thereby curing them into a solid state. The photocuring reaction is essentially a polymerization and cross-linking reaction initiated by light.

[0004] Polyester acrylate is the most commonly used resin in the field of photocuring applications and is widely used. It is mainly prepared by reacting dibasic acid (anhydride) with small molecule polyol in a certain ratio to obtain polyester, which is then esterified with acrylic acid with double bonds under catalyst conditions to obtain polyester acrylate resin. Polyester acrylate is widely used in wood products, printing, ink, electronics and other fields due to its unique properties.

[0005] At present, with the advancement of science and technology and the improvement of environmental awareness, photocuring technology is developing in a more efficient, environmentally friendly and diversified direction. Most polyester acrylate resins on the market now have a wide range of applications and good cost performance. However, there are still relatively few more detailed application directions and more targeted performance development. The present invention provides a method for preparing a modified polyester acrylate resin with good leveling properties, which can make the coating film have good leveling, no orange grain phenomenon, and no shrinkage cavity phenomenon. Summary of the invention

[0006] The main purpose of the present invention is to improve the performance of some polyester acrylates and to provide a method for preparing a modified polyester acrylate resin with good leveling properties.

[0007] The technical solution of the present invention is achieved in this way:

[0008] A method for preparing a modified polyester acrylate resin with good leveling properties comprises the following steps:

[0009] (1) Synthesis of hydroxyl-terminated intermediate A: polyester polyol A

[0010] Mix diol, triol, tetraol and organic anhydride in proportion, then add catalyst, antioxidant and solvent, and perform reflux reaction until the acid value drops below 11 mgKOH / g to obtain terminal hydroxyl intermediate A;

[0011] (2) Semi-finished product B: Synthesis of polyester acrylate B

[0012] On the basis of intermediate A, a certain proportion of monoacid, triol, tetraol and acrylic acid monomer are added, and a catalyst, polymerization inhibitor, antioxidant and solvent are added at the same time, and reflux reaction is carried out under air; until the acid value drops below 20 mgKOH / g, the reaction is terminated, vacuum is drawn and the solvent is removed to obtain polyester acrylate resin B;

[0013] (3) Finished product C: Synthesis of modified polyester acrylate C

[0014] On the basis of polyester acrylate resin B, a certain proportion of catalyst and epoxy group-containing compound are added, and the mixture is kept warm at a suitable temperature until the acid value drops below 10 mgKOH / g to obtain a modified polyester acrylate resin.

[0015] As a preferred embodiment, the method for preparing the modified polyester acrylate photocurable resin described above comprises the following steps:

[0016] (1) Synthesis of hydroxyl-terminated intermediate A: polyester polyol A

[0017] Adding diol, triol, tetraol and organic anhydride together in mass proportion, adding 1-1.5% catalyst, 0.2-0.3% antioxidant and 15-20% solvent based on the total mass of the materials, heating and refluxing water until the acid value is ≤11 mgKOH / g, to obtain polyester polyol A;

[0018] (2) Semi-finished product B: Synthesis of polyester acrylate B

[0019] On the basis of polyester polyol A, monoacid, triol or tetraol and acrylic acid monomer are added according to the mass ratio, and at the same time, 1-1.2% of the total mass of the catalyst, 0.1-0.7% of the polymerization inhibitor, 0.2-0.3% of the antioxidant and 25-33% of the solvent are added, and the mixture is heated under reflux reaction in the presence of air until the acid value is ≤20mgKOH / g; the reaction is terminated and the solvent is removed by vacuum to obtain polyester acrylate B;

[0020] (3) Finished product C: Synthesis of modified polyester acrylate C

[0021] On the basis of polyester acrylate resin B, 0.25-0.3% of the total mass of the material is added with a catalyst and a certain mass ratio of a compound containing epoxy group, and the mixture is kept warm at a suitable temperature until the acid value is ≤10 mgKOH / g to obtain a finished modified polyester acrylate resin.

[0022] As a preferred embodiment, in the preparation method described above, the diol in step (1) is at least one of propylene glycol, diethylene glycol, 1,6-hexanediol and decanediol; in steps (1) and (2), the triol is trimethylolpropane; the tetraol is pentaerythritol; the monoacid in step (2) is lauric acid (dodecanoic acid), and the acrylic acid monomer is acrylic acid; the organic acid anhydride in step (1) is at least one of phthalic anhydride, maleic anhydride and succinic anhydride.

[0023] As a preferred embodiment, in the preparation method described above, the catalyst in step (1) and step (2) is at least one of methanesulfonic acid and p-toluenesulfonic acid, the antioxidant is hypophosphorous acid, and the solvent is at least one of cyclohexane, toluene and xylene.

[0024] As a further improvement of the present invention, in the above-mentioned preparation method, the inhibitor in step (2) is at least one of hydroquinone, p-hydroxyanisole and 2,6-di-tert-butylmethylphenol.

[0025] In the preparation method described above, the organic compound containing an epoxy group in step (3) is at least one of various epoxy resins, epoxy diluents and epichlorohydrin, and the catalyst is at least one of triethylamine, triphenylphosphine, benzyltriethylammonium chloride and benzyltriethylammonium bromide.

[0026] As a further improvement of the present invention, the mass ratio of the diol, triol, tetraol and organic anhydride in step (1) is (52%-63%): (0-16%): (0-16.5%): (22%-33.5%).

[0027] As a further improvement of the present invention, the mass ratio of the polyester polyol, monoacid, triol, tetraol and acrylic acid monomer in step (2) is (33.5%-38.5%): (11%-12.5%): (0-15%): (0-15%): (36%-40%).

[0028] As a further improvement of the present invention, the mass ratio of the polyester acrylate and the compound containing epoxy group in step (3) is (95%-98%): (2%-5%).

[0029] As a further improvement of the present invention, the heating reflux temperature in step (1) is 100-125° C. and the time is 10-13 hours.

[0030] As a further improvement of the present invention, the outlet water temperature of the air reflux in step (2) is 100-130° C. and the time is 8-9 hours.

[0031] As a further improvement of the present invention, the suitable temperature in step (3) is 105-110° C. and the insulation time is 1.5-2 hours.

[0032] Beneficial effects: The present invention discloses a method for preparing a modified polyester acrylate resin with good leveling properties. Compared with general polyester acrylates, the resin has better practicality during use, can make the coating film flatter faster, has no shrinkage cavities, has a high product yield, has better flexibility and adhesion, and has a wider range of applications. DETAILED DESCRIPTION

[0033] The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the specific material ratios, process conditions and results described in the implementation cases are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims. All technologies implemented based on the above content of the present invention belong to the scope of the present invention.

[0034] Example 1

[0035] A method for preparing a modified polyester acrylate with good leveling properties comprises the following steps:

[0036] In the first step, 261.6g of diethylene glycol, 108g of maleic anhydride, 77.2g of pentaerythritol, 7g of p-toluenesulfonic acid, 1.4g of hypophosphorous acid and 90g of toluene are added to a four-necked flask. After stirring evenly, the temperature is raised to 103°C with an electric heating jacket. During the reflux period, the temperature in the flask begins to rise slowly, and the final temperature is between 118-125°C. The reflux is maintained for 10-13 hours, and the acid ester is measured in the sample control ≤11mgKOH / g. The polyester polyol is obtained and cooled to room temperature for the second step.

[0037] In the second step, 164.8g of pentaerythritol, 31.8g of 1,6-hexanediol, 530g of acrylic acid, 14g of p-toluenesulfonic acid, 3.4g of hypophosphorous acid, 1.5g of hydroquinone and 500g of toluene are added to the above four-necked flask, and air is continuously introduced after stirring evenly. The temperature is slowly raised with an electric heating jacket to about 104°C and reflux begins. The reflux state is maintained for 8-9 hours, during which the temperature is slowly raised to 125-130°C. The acid value is controlled to be ≤20mgKOH / g during sampling. After the acid value is qualified, the solvent is removed. Polyester acrylate is obtained.

[0038] In the third step, 34.4g of epoxy diluent SM-622 (produced by Jiangsu Sanmu Chemical Co., Ltd.) and 3.5g of benzyltriethylammonium chloride were added to the above four-necked flask. The temperature was maintained at 105-110°C in the state of ventilation for 1.5-2 hours. The acid value of the sample was ≤10mgKOH / g, and a modified polyester acrylate with good leveling property was obtained.

[0039] Example 2

[0040] A method for preparing a modified polyester acrylate with good leveling properties comprises the following steps:

[0041] In the first step, 292g of diethylene glycol, 184g of phthalic anhydride, 80g of pentaerythritol, 8g of methanesulfonic acid, 1.6g of hypophosphorous acid and 100g of toluene are placed in a four-necked flask. After stirring evenly, the temperature is raised to 103°C with an electric heating jacket. During the reflux period, the temperature in the flask begins to rise slowly, and the final temperature is between 118-125°C. Keep reflux for 10-13 hours, and take samples to control the acid ester ≤11mgKOH / g. The polyester polyol is obtained and cooled to room temperature for the second step.

[0042] In the second step, 208g of pentaerythritol, 168g of lauric acid, 547g of acrylic acid, 16g of methylsulfonic acid, 3.8g of hypophosphorous acid, 1.7g of hydroquinone and 547g of toluene are added to the four-necked flask, and air is continuously introduced after stirring evenly. The temperature is slowly raised with an electric heating jacket to about 104°C and reflux begins. The reflux state is maintained for 8-9 hours, during which the temperature is slowly raised to 125-130°C. The acid value is controlled to be ≤20mgKOH / g during sampling. After the acid value is qualified, the solvent is removed. Polyester acrylate is obtained.

[0043] In the third step, 54g of epoxy resin SM828 (produced by Jiangsu Sanmu Chemical Co., Ltd.) and 4g of triphenylphosphine are put into a flask. The temperature is maintained at 105-110°C in a state of ventilation for 1.5-2 hours. The acid value of the sample is ≤10mgKOH / g, and a modified polyester acrylate with good leveling property is obtained.

[0044] Comparative Example 1

[0045] Compared with Example 1 and Example 2, the difference is that no long-chain alcohol or long-chain acid is added in the second step.

[0046] The details are as follows:

[0047] In the first step, 262g of diethylene glycol, 163g of maleic anhydride, 77g of pentaerythritol, 7g of p-toluenesulfonic acid, 1.4g of hypophosphorous acid and 90g of toluene are placed in a four-necked flask. After stirring evenly, the temperature is raised to 103°C with an electric heating jacket. During the reflux period, the temperature in the flask begins to rise slowly, and the final temperature is between 118-125°C. Keep reflux for 10-13 hours, and take samples to control the acid ester ≤11mgKOH / g. The polyester polyol is obtained and cooled to room temperature for the second step.

[0048] In the second step, 185g of pentaerythritol, 530g of acrylic acid, 14g of p-toluenesulfonic acid, 3.4g of hypophosphorous acid, 1.5g of hydroquinone and 500g of toluene are continuously added to the above four-necked flask, and air is continuously introduced after stirring evenly. The temperature is slowly raised with an electric heating jacket to about 104°C and reflux begins. The reflux state is maintained for 8-9 hours, during which the temperature is slowly raised to 125-130°C. The acid value is controlled to be ≤20mgKOH / g during sampling. After the acid value is qualified, the solvent is removed. Polyester acrylate is obtained.

[0049] Step 3: Add 54g of epoxy resin SM827 (Jiangsu Sanmu) and 4g of benzyltriethylammonium chloride into a flask. Maintain the temperature at 105-110°C in a state of ventilation for 1.5-2 hours. The acid value of the sample is ≤10mgKOH / g, and a modified polyester acrylate resin is obtained.

[0050] Test Example 1

[0051] The leveling effects of the modified polyester acrylate resins prepared in Examples 1 and 2 of the present invention and Comparative Example 1 were compared. The resins were evenly brushed on tinplate (50 mm*120 mm) to compare the time it took for the brush marks to disappear. The results were shown in Table 1 below, referring to the coating leveling determination method of GBT 1750-1979.

[0052] Table 1

[0053] Coating thickness 200 microns Time for brush marks to disappear (minutes) Example 1 3.5-4 minutes Example 2 3-3.5 minutes Comparative Example 1 6-10 minutes

[0054] It can be seen from Table 1 above that the modified polyester acrylate resin prepared in Examples 1-2 of the present invention has excellent leveling properties.

[0055] Test Example 2

[0056] The basic properties of the modified polyester acrylate resins prepared in Examples 1-2 of the present invention and Comparative Example 1 were compared. The coatings were directly cured on a UV curing machine at a speed of 1KW and 4 seconds / time. The flexibility test was based on GB / T1731-1993, and the adhesion test was based on GB / T9286-1998. The results are shown in Table 2 below.

[0057] Table 2 Results comparison

[0058]

[0059] The flexibility and adhesion test experiments in Table 2 above show that the modified polyester acrylate resin prepared in the present invention has excellent flexibility and adhesion.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified polyester acrylate resin with good leveling properties, characterized in that: It includes the following steps: (1) Synthesis of hydroxyl-terminated intermediate A: polyester polyol A Mix diol, triol, tetraol and organic anhydride in proportion, then add catalyst, antioxidant and solvent, and perform reflux reaction until the acid value drops below 11 mgKOH / g to obtain terminal hydroxyl intermediate A; (2) Semi-finished product B: Synthesis of polyester acrylate B On the basis of intermediate A, a certain proportion of monoacid, triol, tetraol and acrylic acid monomer are added, and a catalyst, polymerization inhibitor, antioxidant and solvent are added at the same time, and reflux reaction is carried out under air; until the acid value drops below 20 mgKOH / g, the reaction is terminated, vacuum is drawn and the solvent is removed to obtain polyester acrylate resin B; (3) Finished product C: Synthesis of modified polyester acrylate C On the basis of polyester acrylate resin B, a certain proportion of catalyst and epoxy group-containing compound are added, and the mixture is kept warm at a suitable temperature until the acid value drops below 10 mgKOH / g to obtain a modified polyester acrylate resin.

2. The method for preparing a modified polyester acrylate photocurable resin according to claim 1, characterized in that: It includes the following steps: (1) Synthesis of hydroxyl-terminated intermediate A: polyester polyol A Adding diol, triol, tetraol and organic anhydride together in mass proportion, adding 1-1.5% catalyst, 0.2-0.3% antioxidant and 15-20% solvent based on the total mass of the materials, heating and refluxing water until the acid value is ≤11 mgKOH / g, to obtain polyester polyol A; (2) Semi-finished product B: Synthesis of polyester acrylate B On the basis of polyester polyol A, monoacid, triol or tetraol and acrylic acid monomer are added according to the mass ratio, and at the same time, 1-1.2% of the total mass of the catalyst, 0.1-0.7% of the polymerization inhibitor, 0.2-0.3% of the antioxidant and 25-33% of the solvent are added, and the mixture is heated under reflux reaction in the presence of air until the acid value is ≤20mgKOH / g; the reaction is terminated and the solvent is removed by vacuum to obtain polyester acrylate B; (3) Finished product C: Synthesis of modified polyester acrylate C On the basis of polyester acrylate resin B, 0.25-0.3% of the total mass of the material is added with a catalyst and a certain mass ratio of a compound containing epoxy group, and the mixture is kept warm at a suitable temperature until the acid value is ≤10 mgKOH / g to obtain a finished modified polyester acrylate resin.

3. The preparation method according to claim 1 or 2, characterized in that: The diol in step (1) is at least one of propylene glycol, diethylene glycol, 1,6-hexanediol and decanediol; in step (1) and step (2), the triol is trimethylolpropane; the tetraol is pentaerythritol; the monoacid in step (2) is lauric acid, and the acrylic acid monomer is acrylic acid; the organic anhydride in step (1) is at least one of phthalic anhydride, maleic anhydride and succinic anhydride.

4. The preparation method according to claim 1 or 2, characterized in that: In step (1) and step (2), the catalyst is at least one of methanesulfonic acid and p-toluenesulfonic acid; the antioxidant is hypophosphorous acid; and the solvent is at least one of cyclohexane, toluene and xylene.

5. The preparation method according to claim 1 or 2, characterized in that: In step (2), the inhibitor is at least one of hydroquinone, p-hydroxyanisole and 2,6-di-tert-butylmethylphenol.

6. The preparation method according to claim 1 or 2, characterized in that: In step (3), the organic compound containing epoxy group is at least one of various epoxy resins, epoxy diluents and epichlorohydrin; and the catalyst is at least one of triethylamine, triphenylphosphine, benzyltriethylammonium chloride and benzyltriethylammonium bromide.

7. The preparation method according to claim 1 or 2, characterized in that: In step (1), the mass ratio of the diol, triol, tetraol and organic anhydride is (52%-63%): (0-16%): (0-16.5%): (22%-33.5%).

8. The preparation method according to claim 1 or 2, characterized in that: In step (2), the mass ratio of the polyester polyol A, monoacid, triol, tetraol and acrylic acid monomer is (33.5%-38.5%): (11%-12.5%): (0-15%): (0-15%): (36%-40%).

9. The preparation method according to claim 1 or 2, characterized in that: In step (3), the mass ratio of the polyester acrylate resin B to the compound containing epoxy group is (95%-98%): (2%-5%).

10. The preparation method according to claim 1 or 2, characterized in that: In step (1), the heating reflux temperature is 100-125° C. and the time is 7-8 hours; In step (2), the temperature of the water outlet of the air reflux is 100-130° C. and the time is 8-9 hours; In step (3), the suitable temperature is 105-110° C. and the insulation time is 1.5-2 hours.

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