Thermosetting acrylic resin, preparation method thereof and gloss oil

Abstract

The invention provides thermosetting acrylic resin and a preparation method and gloss oil thereof, and the thermosetting acrylic resin is prepared from the following raw materials in parts by weight: 30-60 parts of styrene, 4-10 parts of an acrylate monomer, 10-20 parts of a hydroxyl-containing acrylic monomer, 2-5 parts of an acrylic monomer, 1-5 parts of a monofunctional acrylic phosphate monomer, 1.2-5.5 parts of an initiator and 20-90 parts of an organic solvent. The monofunctional acrylic phosphate monomer is introduced into an acrylic resin raw material, so that the acrylic phosphate monomer plays a role in catalyzing the reaction of hydroxyl of the acrylic resin and amino resin when the obtained acrylic resin and amino resin are mixed and reacted, namely, the acrylic phosphate monomer has a self-catalysis effect, and the reaction temperature between the hydroxyl and the amino resin can be reduced; performance reduction caused by addition of an acid catalyst during gloss oil preparation is avoided; by designing the formula of the acrylic resin, the curing temperature can be reduced to 90-120 DEG C.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a thermosetting acrylic resin and a preparation method thereof and varnish. Background Art

[0002] Acrylic amino varnish is widely used in automotive OEM paint, industrial paint and other industries because of its good hardness, gloss, fullness, gloss and color retention. However, most acrylic amino varnishes have a curing temperature of 140-150℃, and have the disadvantages of high baking temperature, high energy consumption, poor water resistance, and unsuitability for plastic electroplated parts and other substrates that are not resistant to high temperatures, which seriously limits its application scope.

[0003] In order to reduce the baking temperature and speed up the curing speed, an acid catalyst is often added to the raw materials of acrylic amino varnish. For example, the Chinese invention patent with the publication number CN111363432B provides a low-temperature curing yellowing-resistant energy-saving varnish, wherein the raw materials for preparing the varnish include, by weight, 60 to 70 parts of main resin, 2 to 5 parts of wax powder, 5 to 15 parts of amino resin, 12 to 18 parts of solvent and 0.1 to 0.5 parts of closed acid catalyst; the main resin is selected from one or more of acrylic resin, alkyd resin and polyester resin. The varnish of the above-mentioned prior art can reduce the curing temperature of the varnish applied to the metal packaging can by controlling the raw materials for preparing the varnish, and can be cured at 120 to 130°C. However, the addition of an acid catalyst will affect the cross-linking curing rate of the acrylic resin and the amino group, and will also have an important impact on the hardness, water resistance and salt spray resistance of the paint film.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The object of the present invention is to provide a thermosetting acrylic resin and a preparation method thereof and a varnish in view of the defects and shortcomings of the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The invention provides a thermosetting acrylic resin. The raw materials for preparing the thermosetting acrylic resin include, by weight, 30-60 parts of styrene, 4-10 parts of acrylate monomers, 10-20 parts of hydroxyl-containing acrylic monomers, 2-5 parts of acrylic acid monomers, 1-5 parts of monofunctional acrylic phosphate monomers, 1.2-5.5 parts of initiators, and 20-90 parts of organic solvents.

[0008] By introducing a monofunctional acrylic phosphate monomer into the acrylic resin raw material, the acrylic phosphate monomer plays a role in catalyzing the reaction between the hydroxyl group of the acrylic resin and the amino resin when the obtained acrylic resin is mixed with the amino resin, that is, it has a self-catalytic effect, which can reduce the reaction temperature between the hydroxyl group and the amino resin, and avoid the performance degradation caused by the addition of an acid catalyst when preparing varnish; by designing the formula of the acrylic resin, the curing temperature can be reduced to 90-120°C.

[0009] According to the above scheme, the acrylic acid ester monomer is one or both of butyl acrylate and ethyl acrylate.

[0010] According to the above scheme, the hydroxyl-containing acrylic monomer is one or both of hydroxyethyl acrylate and hydroxyethyl methacrylate.

[0011] According to the above scheme, the acrylic monomer is one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate.

[0012] According to the above scheme, the monofunctional acrylic phosphate monomer is one or both of methacryloyloxyethyl phosphate and ethylene glycol methacrylate phosphate.

[0013] According to the above scheme, the initiator is one or more of benzoyl peroxide, diisopropylbenzene peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, azobisisobutyronitrile, tert-butyl peroxide-2-ethylhexanoate, and di-tert-amyl peroxide.

[0014] According to the above scheme, the organic solvent includes 10-30 parts of alcohol solvent, 5-30 parts of ester solvent and 5-30 parts of benzene solvent.

[0015] According to the above scheme, the alcohol solvent is one or more of isobutanol, n-butanol, ethanol, and methanol; the ester solvent is one or more of butyl acetate, ethyl acetate, propyl acetate, and sec-butyl acetate; the benzene solvent is one or more of toluene, xylene, trimethylbenzene, and tetramethylbenzene.

[0016] The present invention also provides a method for preparing a thermosetting acrylic resin, comprising the following steps:

[0017] (1) adding an organic solvent into a reactor and heating the reactor to reflux;

[0018] (2) adding styrene, acrylate monomer, hydroxyl-containing acrylic monomer, acrylic acid monomer, monofunctional acrylic phosphate monomer, initiator, and organic solvent into a dropping tank and mixing to obtain a mixed solution; after reflux begins, adding the mixed solution dropwise into the reactor and controlling the addition to be completed within 4 hours;

[0019] (3) Using an organic solvent to rinse the remaining mixed solution in the dropping tank, add it into the reactor and keep it warm for 2 hours;

[0020] (4) Add initiator and organic solvent and continue to keep warm until the reaction is complete.

[0021] According to the above scheme, the step (4) is added twice, each time the mixed solution of the initiator and the organic solution is added dropwise into the reactor, the addition is completed within 30 minutes, and the reaction is kept warm for 2 hours.

[0022] The residual reaction monomers can be eliminated by adding initiators and organic solvents, which is beneficial to improving the conversion rate.

[0023] The present invention also provides a varnish, wherein the raw materials for preparing the varnish include, by weight, 40-70 parts of the above-mentioned thermosetting acrylic resin, 10-30 parts of amino resin, and 10-50 parts of organic solvent.

[0024] According to the above scheme, the raw materials for preparing the varnish also include 0.1-0.5 parts of a wetting and dispersing agent and 0.01-0.5 parts of a defoaming agent.

[0025] The thermosetting acrylic resin is added to the varnish, and the acrylic resin has a self-catalytic effect, which can reduce the curing problem of the thermosetting acrylic resin and the amino resin, and avoid the negative impact of the addition of the acid catalyst on the hardness, water resistance and salt spray resistance of the paint film when preparing the varnish.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention introduces a monofunctional acrylic phosphate monomer into the acrylic resin raw material, so that when the obtained acrylic resin is mixed with the amino resin for reaction, the acrylic phosphate monomer plays a role in catalyzing the reaction between the hydroxyl group of the acrylic resin and the amino resin, that is, it has a self-catalytic effect, which can reduce the reaction temperature between the hydroxyl group and the amino resin, and avoids the addition of an acid catalyst when preparing varnish, resulting in a decrease in performance.

[0028] 2. The present invention designs the formula of acrylic resin so that the curing temperature can be reduced to 90-120°C. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Example 1

[0031] The invention provides a thermosetting acrylic resin. The raw materials for preparing the thermosetting acrylic resin include, by weight, 30 parts of styrene, 4 parts of acrylate monomers, 10 parts of hydroxyl-containing acrylic monomers, 2 parts of acrylic acid monomers, 1 part of monofunctional acrylic phosphate monomers, 1.2 parts of initiators, and 20 parts of organic solvents.

[0032] Among them, the acrylate monomer is butyl acrylate, the hydroxyl-containing acrylic monomer is hydroxyethyl acrylate, the acrylic acid monomer is acrylic acid, the monofunctional acrylic phosphate monomer is methacryloyloxyethyl phosphate, the initiator is benzoyl peroxide, and the organic solvent includes 10 parts of n-butanol, 5 parts of butyl acetate, and 5 parts of toluene.

[0033] The preparation method of the thermosetting acrylic resin comprises the following steps:

[0034] (1) Add 8 parts of n-butanol, 3 parts of butyl acetate, and 2.5 parts of toluene into a reactor and heat to reflux;

[0035] (2) adding 30 parts of styrene, 4 parts of butyl acrylate, 10 parts of hydroxyethyl acrylate, 2 parts of acrylic acid, 1 part of methacryloyloxyethyl phosphate, 1 part of benzoyl peroxide, 2 parts of n-butanol, and 1 part of toluene into a dropping tank and mixing to obtain a mixed solution; after reflux begins, dripping the mixed solution into the reactor and controlling the dripping to be completed within 4 hours;

[0036] (3) Use 0.5 parts of toluene to rinse the remaining mixed solution in the dropping tank and add it into the reactor, and keep it warm for 2 hours;

[0037] (4) adding initiator and organic solvent, and continuing to keep warm until the reaction is completed; wherein, the step (4) is added in two steps: a. dripping a mixture of 0.1 part benzoyl peroxide and 1 part toluene into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours; b. dripping a mixture of 0.1 part benzoyl peroxide and 2 parts butyl acetate into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours.

[0038] The present invention also provides a varnish, wherein the raw materials for preparing the varnish include, by weight, 40 parts of the above-mentioned thermosetting acrylic resin, 10 parts of amino resin, 10 parts of toluene, 0.1 parts of a wetting and dispersing agent, and 0.01 parts of a defoaming agent. The varnish is obtained by mixing the raw materials for preparing the varnish.

[0039] Example 2

[0040] The invention provides a thermosetting acrylic resin. The raw materials for preparing the thermosetting acrylic resin include, by weight, 50 parts of styrene, 7 parts of acrylate monomers, 15 parts of hydroxyl-containing acrylic monomers, 4 parts of acrylic acid monomers, 3 parts of monofunctional acrylic phosphate monomers, 3.5 parts of initiators, and 50 parts of organic solvents.

[0041] Among them, the acrylate monomer is ethyl acrylate, the hydroxyl-containing acrylic monomer is hydroxyethyl methacrylate, the acrylic monomer includes 2 parts of methacrylic acid and 2 parts of methyl acrylate, the monofunctional acrylic phosphate monomer is ethylene glycol methacrylate phosphate, the initiator includes 2 parts of diisopropyl peroxide and 1.5 parts of tert-butyl perbenzoate, and the organic solvent includes 10 parts of n-butanol, 10 parts of ethanol, 10 parts of ethyl acetate, 5 parts of propyl acetate, 5 parts of xylene, and 10 parts of trimethylolbenzene.

[0042] The preparation method of the thermosetting acrylic resin comprises the following steps:

[0043] (1) Add 10 parts of n-butanol, 10 parts of ethyl acetate and 5 parts of xylene into a reactor and heat to reflux;

[0044] (2) adding 50 parts of styrene, 7 parts of ethyl acrylate, 15 parts of hydroxyethyl methacrylate, 2 parts of methacrylic acid, 2 parts of methyl acrylate, 3 parts of ethylene glycol methacrylate phosphate, 1.5 parts of tert-butyl perbenzoate, 10 parts of ethanol, and 2 parts of trimethylbenzene into a dropping tank and mixing to obtain a mixed solution; after reflux begins, dripping the mixed solution into the reactor and controlling the dripping to be completed within 4 hours;

[0045] (3) Use 5 parts of trimethylbenzene to rinse the remaining mixed solution in the dropping tank and add it into the reactor, and keep it warm for 2 hours;

[0046] (4) adding initiator and organic solvent, and continuing to keep warm until the reaction is completed; wherein, the step (4) is added in two steps: a. dripping a mixture of 1 part of diisopropylbenzene peroxide and 5 parts of trimethylbenzene into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for reaction for 2 hours; b. dripping a mixture of 1 part of diisopropylbenzene peroxide and 5 parts of propyl acetate into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for reaction for 2 hours.

[0047] The present invention also provides a varnish, wherein the raw materials for preparing the varnish include, by weight, 50 parts of the above-mentioned thermosetting acrylic resin, 20 parts of amino resin, 30 parts of toluene, 0.3 parts of a wetting and dispersing agent, and 0.2 parts of a defoaming agent. The varnish is obtained by mixing the raw materials for preparing the varnish.

[0048] Example 3

[0049] The invention provides a thermosetting acrylic resin. The raw materials for preparing the thermosetting acrylic resin include, by weight, 60 parts of styrene, 10 parts of acrylate monomers, 20 parts of hydroxyl-containing acrylic monomers, 5 parts of acrylic acid monomers, 5 parts of monofunctional acrylic phosphate monomers, 5.5 parts of initiators, and 90 parts of organic solvents.

[0050] Among them, the acrylate monomer includes 5 parts of butyl acrylate and 5 parts of ethyl acrylate; the hydroxyl-containing acrylic monomer includes 10 parts of hydroxyethyl acrylate and 10 parts of hydroxyethyl methacrylate; the acrylic monomer includes 3 parts of acrylic acid, 2 parts of ethyl methacrylate and 5 parts of ethyl acrylate; the monofunctional acrylic phosphate monomer includes 2 parts of methacryloyloxyethyl phosphate and 3 parts of ethylene glycol methacrylate phosphate; the initiator includes 2.5 parts of di-tert-butyl peroxide and 3 parts of azobisisobutyronitrile; the organic solvent includes 10 parts of isobutyl alcohol, 10 parts of n-butanol, 10 parts of ethanol, 10 parts of butyl acetate, 10 parts of ethyl acetate, 10 parts of propyl acetate, 10 parts of toluene, 10 parts of xylene, and 10 parts of tetramethylbenzene.

[0051] The preparation method of the thermosetting acrylic resin comprises the following steps:

[0052] (1) Add 10 parts of isobutanol, 10 parts of ethanol, 10 parts of butyl acetate, 10 parts of ethyl acetate, and 10 parts of toluene into a reactor and heat to reflux;

[0053] (2) adding 60 parts of styrene, 5 parts of butyl acrylate, 5 parts of ethyl acrylate, 10 parts of hydroxyethyl acrylate, 10 parts of hydroxyethyl methacrylate, 3 parts of acrylic acid, 2 parts of ethyl methacrylate, 5 parts of ethyl acrylate, 2 parts of methacryloyloxyethyl phosphate, 3 parts of ethylene glycol methacrylate phosphate, 2.5 parts of di-tert-butyl peroxide, 10 parts of n-butanol, and 5 parts of xylene into a dropping tank and mixing to obtain a mixed solution; after reflux begins, dropping the mixed solution into the reactor and controlling the dropping to be completed within 4 hours;

[0054] (3) Use 5 parts of xylene to rinse the remaining mixed solution in the dropping tank and add it into the reactor, and keep it warm for 2 hours;

[0055] (4) adding initiator and organic solvent, and continuing to keep warm until the reaction is completed; wherein, the step (4) is added in two steps: a. dripping a mixture of 1 part of azobisisobutyronitrile and 10 parts of tetramethylbenzene into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours; b. dripping a mixture of 2 parts of azobisisobutyronitrile and 10 parts of propyl acetate into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours.

[0056] The present invention also provides a varnish, wherein the raw materials for preparing the varnish include, by weight, 70 parts of the above-mentioned thermosetting acrylic resin, 30 parts of amino resin, 50 parts of toluene, 0.5 parts of wetting and dispersing agent, and 0.5 parts of defoaming agent. The varnish is obtained by mixing the raw materials for preparing the varnish.

[0057] Comparative Example 1

[0058] A thermosetting acrylic resin. The raw materials for preparing the thermosetting acrylic resin include, by weight, 30 parts of styrene, 4 parts of acrylate monomers, 10 parts of hydroxyl-containing acrylic monomers, 2 parts of acrylic acid monomers, 1.2 parts of initiators, and 20 parts of organic solvents.

[0059] Wherein, the acrylate monomer is butyl acrylate, the hydroxyl-containing acrylic monomer is hydroxyethyl acrylate, the acrylic acid monomer is acrylic acid, the initiator is benzoyl peroxide, and the organic solvent includes 10 parts of n-butanol, 5 parts of butyl acetate, and 5 parts of toluene.

[0060] The preparation method of the thermosetting acrylic resin comprises the following steps:

[0061] (1) Add 8 parts of n-butanol, 3 parts of butyl acetate, and 2.5 parts of toluene into a reactor and heat to reflux;

[0062] (2) adding 30 parts of styrene, 4 parts of butyl acrylate, 10 parts of hydroxyethyl acrylate, 2 parts of acrylic acid, 1 part of benzoyl peroxide, 2 parts of n-butanol, and 1 part of toluene into a dropping tank and mixing to obtain a mixed solution; after reflux begins, dripping the mixed solution into the reactor and controlling the dripping to be completed within 4 hours;

[0063] (3) Use 0.5 parts of toluene to rinse the remaining mixed solution in the dropping tank and add it into the reactor, and keep it warm for 2 hours;

[0064] (4) adding initiator and organic solvent, and continuing to keep warm until the reaction is completed; wherein, the step (4) is added in two steps: a. dripping a mixture of 0.1 part benzoyl peroxide and 1 part toluene into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours; b. dripping a mixture of 0.1 part benzoyl peroxide and 2 parts butyl acetate into the reactor, the dripping is completed within 30 minutes, and the temperature is kept warm for 2 hours.

[0065] A varnish, wherein the raw materials for preparing the varnish include, by weight, 40 parts of the above-mentioned thermosetting acrylic resin, 10 parts of amino resin, 1 part of p-toluenesulfonic acid, 10 parts of toluene, 0.1 parts of a wetting and dispersing agent, and 0.01 parts of a defoaming agent. The varnish is obtained by mixing the raw materials for preparing the varnish.

[0066] The varnish obtained in Examples 1-3 and Comparative Example 1 was applied to a steel plate respectively, baked at 100°C for 30 minutes, and then subjected to performance tests. Among them, according to GB / T 9286-88 standard, the cross-hatch method was used to test the adhesion of the steel plate; the hardness test was conducted by referring to the standard test method for pencil hardness of coatings in ASTMD3363-00, using a Mitsubishi pencil test with a load of 750g; the water resistance test was conducted by soaking the sample in water at 40°C for 1 day and observing the appearance of the sample; the salt resistance test was conducted by soaking the sample in salt water for 48 hours according to GB / T1771-2007 standard and observing the appearance of the eyelid. The performance test results are shown in Table 1 below.

[0067] Table 1

[0068]

[0069] As can be seen from Table 1, the water resistance and salt spray resistance of the varnish in Comparative Example 1 decreased due to the addition of the strong acid catalyst p-toluenesulfonic acid. However, the thermosetting acrylic resin added to the varnish of the present invention has catalytic properties, which reduces the curing temperature of the varnish, and effectively improves the water resistance and salt spray resistance of the obtained varnish, thereby avoiding the performance degradation caused by the addition of the acid catalyst during the preparation of the varnish.

[0070] The above description is only a preferred embodiment of the present invention, so all equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A thermosetting acrylic resin, wherein the raw materials for preparing the thermosetting acrylic resin are calculated by weight, characterized in that: The invention comprises 30-60 parts of styrene, 4-10 parts of acrylate monomer, 10-20 parts of hydroxyl-containing acrylic monomer, 2-5 parts of acrylic acid monomer, 1-5 parts of monofunctional acrylic phosphate monomer, 1.2-5.5 parts of initiator and 20-90 parts of organic solvent.

2. The thermosetting acrylic resin according to claim 1, characterized in that The acrylic acid ester monomer is one or both of butyl acrylate and ethyl acrylate.

3. The thermosetting acrylic resin according to claim 1, characterized in that: The hydroxyl-containing acrylic monomer is one or both of hydroxyethyl acrylate and hydroxyethyl methacrylate.

4. The thermosetting acrylic resin according to claim 1, characterized in that: The acrylic monomer is one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate.

5. The thermosetting acrylic resin according to claim 1, characterized in that: The monofunctional acrylic phosphate monomer is one or both of methacryloyloxyethyl phosphate and ethylene glycol methacrylate phosphate.

6. The thermosetting acrylic resin according to claim 1, characterized in that: The initiator is one or more of benzoyl peroxide, diisopropylbenzene peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, azobisisobutyronitrile, tert-butyl peroxide-2-ethylhexanoate, and di-tert-amyl peroxide.

7. The thermosetting acrylic resin according to claim 1, characterized in that: The organic solvent includes 10-30 parts of alcohol solvent, 5-30 parts of ester solvent and 5-30 parts of benzene solvent.

8. The thermosetting acrylic resin according to claim 7, characterized in that: The alcohol solvent is one or more of isobutanol, n-butanol, ethanol, and methanol; the ester solvent is one or more of butyl acetate, ethyl acetate, propyl acetate, and sec-butyl acetate; the benzene solvent is one or more of toluene, xylene, trimethylbenzene, and tetramethylbenzene.

9. A method for preparing the thermosetting acrylic resin according to any one of claims 1 to 8, comprising the following steps: (1) adding an organic solvent into a reactor and heating the reactor to reflux; (2) adding styrene, acrylate monomer, hydroxyl-containing acrylic monomer, acrylic acid monomer, monofunctional acrylic phosphate monomer, initiator, and organic solvent into a dropping tank and mixing to obtain a mixed solution; after reflux begins, adding the mixed solution dropwise into the reactor and controlling the addition to be completed within 4 hours; (3) Using an organic solvent to rinse the remaining mixed solution in the dropping tank, add it into the reactor and keep it warm for 2 hours; (4) Add initiator and organic solvent and continue to keep warm until the reaction is complete.

10. A varnish, wherein the raw materials for preparing the varnish include, by weight, 40-70 parts of the thermosetting acrylic resin according to any one of claims 1 to 8, 10-30 parts of an amino resin, and 10-50 parts of an organic solvent.

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