An acrylate monomer and its application in photocurable functional coatings

Abstract

The present invention discloses an acrylate monomer and its application in a photocurable functional coating. The structure of the acrylate monomer is shown in formula (I): #imgabs0# The acrylate monomer provided by the present invention contains a thioether bond structure, an ethoxylated structure and an acrylate bond. The thioether bond structure can be well anchored to a metal interface, thereby giving the monomer good adhesion to the metal. The ethoxylated structure can promote the monomer to have better compatibility in the formulation system, promote the thioether bond to anchor to the metal surface, improve the adhesion of the functional monomer to the metal substrate, and provide a new material for the functional coating on the metal substrate.

Description

Technical Field

[0001] The invention belongs to the field of photocurable coatings, and in particular relates to an acrylate monomer and application thereof in photocurable functional coatings. Background Art

[0002] Metal is the most common inorganic material in the chemical industry. Oxygen in the air will undergo an oxidation-reduction reaction with the metal, causing the metal to oxidize and rust, which seriously affects the performance of the metal. Therefore, a protective coating needs to be applied on the metal surface.

[0003] Metal coating protective coatings are mainly divided into traditional solvent-based construction coatings and UV light-curing coatings. Among them, traditional solvent-based coatings are easier to meet various performance requirements such as adhesion on metal substrates, but the presence of solvents does not meet my country's requirements for environmental protection and zero VOCs emissions; although UV light-curing coatings are solvent-free, have high curing efficiency, are simple to operate and easy to construct, the existing UV light-curing coatings have weak adhesion to metal substrates, resulting in limited use of UV light-curing coatings on metal substrates. Summary of the invention

[0004] In view of the problem that the prior art UV light-curing coating has poor adhesion to metal substrates, the present invention provides an acrylate monomer. The provided acrylate monomer contains a thioether bond structure, an ethoxylated structure and an acrylate bond. The thioether bond structure can be well anchored to the metal interface, thereby giving the monomer good adhesion to the metal. The ethoxylated structure can promote the monomer to have better compatibility in the formulation system, promote the thioether bond to anchor to the metal surface, improve the adhesion of the functional monomer to the metal substrate, and provide a new material for the functional coating on the metal substrate.

[0005] The object of the present invention is to provide an acrylate monomer, the structure of which is shown in formula (I):

[0006]

[0007] Wherein, A is selected from an alkylene group, a heterocycloalkyl group or an aryl group having 2 to 4 carbon atoms, R is selected from H or CH3, and n is an integer of 1 to 4.

[0008] Preferably, the structure of the acrylic acid ester monomer is as shown in formula (I):

[0009]

[0010] Wherein, A is selected from phenyl, R is selected from H, and n is an integer of 1 to 4.

[0011] Preferably, the structure of the acrylic acid ester monomer is as shown in formula (I):

[0012]

[0013] Among them, A is selected from an alkylene group having 2 carbon atoms, R is selected from CH3, and n is 2.

[0014] Another object of the present invention is to provide a method for preparing the acrylic ester monomer, comprising the following steps:

[0015] S1. A hydroxy compound containing a thioether bond, ethylene oxide and a strong base catalyst are mixed and reacted to obtain a polyether hydroxy compound containing a thioether bond;

[0016] S2. The thioether-containing polyether hydroxy compound, acrylic monomer, strong acid catalyst, polymerization inhibitor and water-carrying agent are mixed and reacted to obtain an acrylic ester monomer;

[0017] The structure of the hydroxy compound containing a thioether bond is shown in formula (II):

[0018]

[0019] The structure of the polyether hydroxy compound containing a thioether bond is shown in formula (III):

[0020]

[0021] The structure of the acrylic compound is shown in formula (IV):

[0022]

[0023] Wherein, A is selected from an alkylene group, a heterocycloalkyl group or an aryl group having 2 to 4 carbon atoms, R is selected from H or CH3, and n is an integer of 1 to 4.

[0024] Preferably, the structure of the acrylic acid ester monomer is as shown in formula (I):

[0025]

[0026] Wherein, A is selected from phenyl, R is selected from H, and n is an integer of 1 to 4.

[0027] Preferably, the structure of the acrylic acid ester monomer is as shown in formula (I):

[0028]

[0029] Among them, A is selected from an alkylene group having 2 carbon atoms, R is selected from CH3, and n is 2.

[0030] Preferably, in S1, the molar ratio of the hydroxy compound containing a thioether bond to ethylene oxide is 1:1-4.

[0031] Preferably, in S1, the amount of the alkaline catalyst used is 1000 to 4000 ppm of the total reaction raw materials.

[0032] Preferably, in S1, the strong base catalyst includes one of potassium hydroxide, sodium hydroxide and potassium tert-butoxide.

[0033] Preferably, in S1, the reaction temperature is 80-120° C. and the reaction time is 2-4 hours.

[0034] Preferably, in S2, the molar ratio of the polyether hydroxy compound containing a thioether bond to the acrylic compound is 1:1 to 1.2.

[0035] Preferably, in S2, the amount of the strong acid catalyst used is 1 to 5 wt % of the total reaction raw materials.

[0036] Preferably, in S2, the amount of the water-carrying agent is 30-50 wt % of the total reaction raw materials.

[0037] Preferably, in S2, the amount of the polymerization inhibitor used is 1000 to 5000 ppm of the total reaction raw materials.

[0038] Preferably, in S2, the strong acid catalyst includes at least one of potassium bisulfate and sodium bisulfate.

[0039] Preferably, in S2, the inhibitor includes at least one of p-hydroxyanisole, BHT, copper salt, aluminum salt, and phenothiazine.

[0040] Preferably, in S2, the water-carrying agent includes at least one of cyclohexane and toluene.

[0041] Preferably, in S2, an antioxidant is also added during the reaction.

[0042] Preferably, in S2, the antioxidant comprises hypophosphorous acid.

[0043] Preferably, in S2, the amount of the antioxidant is 0.05-0.3 wt % of the total reaction raw materials.

[0044] Preferably, in S2, the reaction temperature is 80-110° C. and the reaction time is 8-16 hours.

[0045] Another object of the present invention is to provide a UV light-curing coating, which is prepared from the acrylic ester monomers.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The acrylic ester monomer provided by the present invention contains a thioether bond structure, an ethoxylated structure and an acrylate bond. The thioether bond structure can be well anchored to the metal interface, thereby giving the monomer good adhesion to the metal. The ethoxylated structure can promote the monomer to have better compatibility in the formulation system and promote the thioether bond to anchor to the metal surface, thereby improving the adhesion of the functional monomer to the metal substrate, and providing a new material for the functional coating on the metal substrate.

[0048] (2) The polyether structure in the acrylic ester monomer of the present invention has a strong dilution ability, which can assist the terminal methylthio group in the molecular structure of the acrylic ester monomer to diffuse to the metal surface and increase the adhesion rate in the UV formulation, thereby enhancing the adhesion of the UV coating to the metal. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0050] TPO: diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide;

[0051] B-165: modified epoxy acrylate, purchased from Guangdong Boxing New Materials Technology Co., Ltd.;

[0052] ACMO: acryloylmorpholine;

[0053] TPGDA: tripropylene glycol diacrylate;

[0054] Photoinitiator 1173: 2-hydroxy-2-methyl-1-phenyl-1-propanone;

[0055] IBOA: isobornyl acrylate;

[0056] Leveling agent: EFKA3777;

[0057] DMAA: dimethylallylamine;

[0058] M4: 4-methylthiobutyl acrylate;

[0059] The raw materials in the examples are all commercially available.

[0060] Example 1

[0061] This embodiment provides an acrylic acid ester monomer M1, and the specific process is as follows:

[0062] S1. Add 2-methylmercaptoethanol (8 mol) to a 2L addition reactor, add potassium hydroxide (0.43 g) with stirring, replace with nitrogen three times, raise the temperature to 100°C, dehydrate for 0.5 hours, adjust the temperature to 100°C, slowly introduce ethylene oxide (15.98 mol) for 3 hours, add and mature, wait until the pressure cannot be reduced, cool and degas the material to obtain crude ether; add phosphoric acid aqueous solution, adjust the pH of the system to about 5.5, add 1000 ppm of antioxidant 1010 (BASF), and then add 0.1 wt% of magnesium silicate adsorbent, dehydrate and filter to obtain refined compound A1;

[0063] S2. In a 500ml straight four-necked flask, add acrylic acid (1 mol), compound A1 (0.98 mol), p-hydroxyanisole (0.030 g), cupric chloride (0.08 g), hypophosphorous acid (0.20 g), sodium bisulfate (2.50 g), and cyclohexane (100 g), slowly heat to 90°C, reflux with water for 10 hours, use a water separator to collect esterification water, and when the esterification water is greater than or equal to the theoretical water yield, the esterification reaction is completed. Add hydroxyphosphine lime to remove the impurity acid in the reaction solution and filter; use hot water to wash to remove the cupric chloride in the reactant, wash with hot water twice, then use saturated brine to wash to remove the water in the product, add 500 ppm p-hydroxyanisole, and remove the solvent by rotary evaporation to obtain functional acrylate monomer M1;

[0064] The H NMR spectrum of M1 is as follows:

[0065] 1 H NMR (CDCl3, 400MHz): 6.30 (d, 1H), 6.08 (tert, 1H), 5.60 (d, 1H), 4.28 (t, 2H), 3.80 ~ 3.65 (t, 8H), 2.58 (t, 2H), 2.12 (s, 3H).

[0066]

[0067] Among them, n=2.

[0068] Example 2

[0069] This embodiment provides an acrylic acid ester monomer M2, and the specific process is as follows:

[0070] S1. Add p-methylthiophenol (4.56 mol) to a 2L addition reactor, stir and add potassium hydroxide (0.28 g), replace with nitrogen three times and then heat to 100°C, dehydrate for 0.5 hours, adjust the temperature to 100°C and slowly introduce ethylene oxide (11.98 mol) for 4 hours. After the addition is completed, ripen until the pressure cannot be reduced, cool and degas the material to obtain crude ether; add aqueous phosphoric acid solution to adjust the pH of the system to about 5.5, add 1000 ppm of antioxidant 1010 (BASF), and then add 0.1 wt% of magnesium silicate adsorbent, dehydrate and filter to obtain refined compound A2;

[0071] S2. In a 1000ml straight four-necked flask, add acrylic acid (1 mol), compound A2 (0.98 mol), p-hydroxyanisole (0.046 g), cupric chloride (0.12 g), hypophosphorous acid (0.25 g), sodium bisulfate (3.82 g), and cyclohexane (165 g), slowly heat to 90°C, reflux with water for 10 hours, use a water separator to collect esterification water, when the esterification water is greater than or equal to the theoretical water yield, the esterification reaction is completed, add hydroxyphosphine lime to remove the impurity acid in the reaction solution, and filter; use hot water washing to remove the cupric chloride in the reactant, wash with hot water twice, and then use saturated brine to wash to remove water in the product; add 500 ppm p-hydroxyanisole, remove the solvent by rotary evaporation, and obtain functional acrylate monomer M2;

[0072] The H NMR spectrum of M2 is as follows:

[0073] 1 H NMR(CDCl3,400MHz):7.50(d,2H),7.30(d,2H),6.35(d,1H),6.12(tert,1H ),5.63(d,1H),4.54(t,2H),4.38(t,2H),3.78~3.60(t,12H),2.60(s,3H).

[0074]

[0075] Among them, n=4.

[0076] Example 3

[0077] S1. Add 2-methylmercaptoethanol (8 mol) to a 2L addition reactor, add potassium hydroxide (0.43 g) with stirring, replace with nitrogen three times, raise the temperature to 100°C, dehydrate for 0.5 hours, adjust the temperature to 100°C, slowly introduce ethylene oxide (15.98 mol) for 3 hours, add and mature, wait until the pressure cannot be reduced, cool and degas the material to obtain crude ether; add phosphoric acid aqueous solution, adjust the pH of the system to about 5.5, add 1000 ppm of antioxidant 1010 (BASF), and then add 0.1 wt% of magnesium silicate adsorbent, dehydrate and filter to obtain refined compound A1;

[0078] S2. In a 500ml straight four-necked flask, methacrylic acid (1 mol), compound A1 (0.98 mol), p-hydroxyanisole (0.035 g), cupric chloride (0.08 g), hypophosphorous acid (0.20 g), sodium bisulfate (3.00 g), and cyclohexane (100 g) were added, and the temperature was slowly raised to 90°C, i.e., the water agent was refluxed for 10 hours, and the esterification water was collected by a water separator. When the esterification water was greater than or equal to the theoretical water yield, the esterification reaction was completed, and hydroxyphosphine lime was added to remove the impurity acid in the reaction solution, and the reaction solution was filtered; the cupric chloride in the reactant was removed by hot water washing, and the hot water was washed twice, and then the product was washed with saturated brine to remove the water; 500 ppm of p-hydroxyanisole was added, and the solvent was removed by rotary evaporation to obtain a functional acrylate monomer M3;

[0079] The H NMR spectrum of M3 is as follows:

[0080] 1 H NMR (CDCl3, 400MHz): 6.12 (d, 1H), 5.64 (d, 1H), 4.25 (t, 2H), 3.80 ~ 3.65 (t, 8H), 2.58 (t, 2H), 2.12 (s, 3H), 2.01 (s, 3H).

[0081]

[0082] Among them, n=2.

[0083] Preparation and performance testing of light-curing coatings:

[0084] Table 1. Composition of coatings.

[0085]

[0086]

[0087] Preparation and performance test of photocurable coating: 15g of the first monomer, 55g of B-165, 33.5g of photoinitiator 117, 0.5g of photoinitiator TPO, 0.3g of leveling agent EFKA3777 and 25g of TPGDA were mixed according to Table 1 to prepare coatings, and coatings of Examples 4 to 6 and Comparative Examples 1 to 4 were obtained respectively. The coatings were scraped on tinplate, cold-rolled steel sheet and galvanized sheet cleaned with alcohol, with a scraping thickness of 6 μm. After coating, the coating was cured by a 500mJ medium-pressure mercury lamp. After curing, the coating was tested by the hundred-grid test method according to the standard "GBT 9286-1998 Scratch Test of Paint and Varnish Film" to test the adhesion of the coating on different metal substrates. If the hundred grids do not fall off, the adhesion is OK, 100 / 100 (the numerator represents the number of grids remaining on the metal coating after tearing with tape / the denominator represents the number of hundred grids drawn on the coating).

[0088] Table 2. Test results of coating properties of Examples 4 to 6 and Comparative Examples 1 to 4.

[0089] coating Tinplate Cold rolled steel sheet Galvanized sheet Example 4 100 / 100 100 / 100 100 / 100 Example 5 100 / 100 100 / 100 100 / 100 Example 6 100 / 100 100 / 100 100 / 100 Comparative Example 1 98 / 100 50 / 100 56 / 100 Comparative Example 2 90 / 100 45 / 100 48 / 100 Comparative Example 3 89 / 100 50 / 100 56 / 100 Comparative Example 4 82 / 100 45 / 100 50 / 100

[0090] As can be seen from Table 2, the acrylate monomers M1-M3 prepared in Examples 1-3 of the present invention are used to prepare coatings, and have good adhesion on tinplate, cold-rolled steel sheets, and galvanized sheets. The conventional monomers DMAA, ACMO, IBOA, and M4 all have varying degrees of adhesion, that is, the thioether-modified polyether acrylate monomers have a good effect on improving the adhesion of the coating on the metal substrate.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, the technicians can still modify or replace the specific implementation mode of the present invention with equivalents, but these modifications or changes do not deviate from the scope of protection of the pending claims of the present application.

Claims

1. An acrylic acid ester monomer, characterized in that: The structure of the acrylic acid ester monomer is shown in formula (I): Formula (I) Among them, A is selected from an alkylene group having 2 carbon atoms, R is selected from CH3, and n is 2.

2. The method for preparing an acrylic acid ester monomer according to claim 1, characterized in that: The steps include: S1. A hydroxy compound containing a thioether bond, ethylene oxide and a strong base catalyst are mixed and reacted to obtain a polyether hydroxy compound containing a thioether bond; S2. The thioether-containing polyether hydroxy compound, acrylic monomer, strong acid catalyst, polymerization inhibitor and water-carrying agent are mixed and reacted to obtain an acrylic ester monomer; The structure of the hydroxy compound containing a thioether bond is shown in formula (II): Formula (II) The structure of the polyether hydroxy compound containing a thioether bond is shown in formula (III): Formula (III) The structure of the acrylic monomer is shown in formula (IV): Formula (IV).

3. The method for preparing an acrylic acid ester monomer according to claim 2, characterized in that: In S1, the molar ratio of the hydroxy compound containing a thioether bond to ethylene oxide is 1:1-4; And / or, the amount of the alkaline catalyst used is 1000-4000 ppm of the total reaction raw materials.

4. The method for preparing an acrylic acid ester monomer according to claim 2, characterized in that: In S1, the strong base catalyst includes one of potassium hydroxide, sodium hydroxide and potassium tert-butoxide.

5. The method for preparing an acrylic acid ester monomer according to claim 2, characterized in that: In S1, the reaction temperature is 80-120° C. and the reaction time is 2-4 hours.

6. The method for preparing an acrylic acid ester monomer according to claim 2, characterized in that: In S2, the molar ratio of the polyether hydroxy compound containing a thioether bond to the carboxylic acid compound is 1:1 to 1.2; And / or, the amount of the strong acid catalyst is 1-5wt% of the total reaction raw materials; And / or, the amount of the water-carrying agent is 30-50wt% of the total reaction raw materials; And / or, the dosage of the polymerization inhibitor is 1000-5000 ppm of the total reaction raw materials.

7. The method for preparing an acrylic acid ester monomer according to claim 2, characterized in that: In S2, the reaction temperature is 80-110° C. and the reaction time is 8-16 hours.

8. A UV light curing coating, characterized in that: The invention is prepared from the acrylic acid ester monomers as claimed in claim 1.

Images