Anti-ultraviolet anti-aging modified acrylic coating resin and preparation method thereof

Abstract

The invention discloses anti-ultraviolet and anti-aging modified acrylic coating resin, which is prepared from the following ingredients in parts by weight: 40 to 70 parts of acrylic resin synthetic monomers, 1 to 8 parts of acrylic modified polyisocyanate monomers, 1 to 8 parts of ultraviolet light absorbers with hydroxyl structures, 0.01 to 0.1 part of catalysts, 0.01 to 0.5 part of radical initiators and 30 to 60 parts of organic solvents. The preparation method comprises the following steps: preparing a functional monomer containing a double-bond structure and an ultraviolet absorption functional group; and uniformly mixing the functional monomer prepared in the previous step with an acrylic resin synthetic monomer and a free radical initiator, slowly dripping into a reaction kettle containing an organic solvent at a constant speed for reaction, cooling and discharging to obtain the coating resin, and testing the performance of the coating resin. The weather-resistant coating has excellent weather resistance, and the film-forming resin prepared by adopting a polymerization method greatly improves the compatibility of anti-ultraviolet micromolecular organic matters and coating resin, and solves the problems of blooming, mildew spots and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to an anti-ultraviolet and anti-aging modified acrylic coating resin and a preparation method thereof. Background Art

[0002] Coatings are applied on the surface of objects to be protected or decorated and can form a continuous film firmly attached to the coated object. They are usually mainly composed of resins, with or without the addition of pigments, fillers, additives, etc., and are prepared as mixtures with organic solvents or water. Coatings generally consist of four basic components: film-forming substances (resins, etc.), pigments, solvents, and additives (auxiliaries). Currently, the resins used for film formation mainly include acrylic resins, polyurethane resins, alkyd resins, epoxy resins, fluorocarbon resins, etc. Since the film-forming resins are mainly high-molecular materials, there are often aging and degradation phenomena. Especially when applied outdoors, the service life of the coating resin is limited. For example, acrylic resins, alkyd resins, and epoxy resins will have aging cracks, and polyurethane resins will show yellowing phenomena. Although fluorocarbon resins have good weather resistance themselves, when inorganic pigments are not added, the protection of the material under the coating is insufficient.

[0003] In previous invention patents, mainly in the form of additives, anti-aging auxiliaries were dispersed in the coating resin by physical blending methods to play a certain anti-aging role. For example, patent CN 108231246 A uses ultraviolet absorbers added to acrylic coatings to improve the anti-aging performance of products. Although this method can improve the weather resistance of products to a certain extent, since most current anti-aging auxiliaries are low-molecular organic compounds, they will become ineffective due to precipitation after a certain time in the coating. In addition, most powder anti-aging auxiliaries have good compatibility with the coating resin due to the action of the solvent when the solvent has not volatilized and the film has not been cured in the coating. However, after production and coating, due to the volatilization of the solvent, the compatibility between the powder anti-aging auxiliary and the coating resin becomes poor, and precipitation defects such as blooming and mildew spots will occur, thereby affecting the use of the product. Summary of the Invention

[0004] The purpose of the present invention is to provide an anti-ultraviolet and anti-aging modified acrylic coating resin and a preparation method thereof to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An anti-ultraviolet and anti-aging modified acrylic coating resin mainly includes acrylic resin synthesis monomers, acrylic modified polyisocyanate monomers, hydroxyl group-containing ultraviolet absorbers, catalysts, free radical initiators, and organic solvents.

[0006] Calculated by weight parts, wherein the acrylic resin synthesis monomer is 40 to 70 parts, the acrylic acid-modified polyisocyanate monomer is 1 to 8 parts, the ultraviolet absorber containing a hydroxyl structure is 1 to 8 parts, the catalyst is 0.01 to 0.1 part, the free radical initiator is 0.01 to 0.5 part, and the organic solvent is 30 to 60 parts.

[0007] The acrylic resin synthesis monomer is one or a combination of several of: methyl methacrylate, ethyl methacrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate, n-octyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, acrylic acid, styrene, vinyl acetate.

[0008] The acrylic acid-modified polyisocyanate monomer is one or a combination of several of: isocyanatoethyl methacrylate, isocyanatoethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2-isocyanato-2-methylpropane-1,3-diyl diacrylate, 2-[O-(1'-methylpropylideneamino)oxycarbonylamino]ethyl methacrylate, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, MOI-DEM, AOI-BM, AOI-BP.

[0009] The ultraviolet absorber containing a hydroxyl structure is one or a combination of several of: 2,4-dihydroxybenzophenone, 2,2,4,4-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone.

[0010] The catalyst is one or a combination of several of: tertiary amine catalyst, organotin catalyst, potassium carboxylate catalyst, zinc carboxylate catalyst, bismuth carboxylate catalyst, titanate catalyst.

[0011] The free radical initiator is one or a combination of several of: azobisisobutyronitrile AIBN, azobisisoheptonitrile ADVN, azobisisovaleronitrile AMBN, 1,1'-azo-cyanocyclohexane ACHN, benzoyl peroxide BPO, tert-amyl peroxy-2-ethylhexanoate TAPO, tert-butyl peroxy-2-ethylhexanoate TBPO, tert-amyl peroxyacetate TAPA, tert-amyl peroxybenzoate TAPB, tert-butyl peroxybenzoate TBPB, dicumyl peroxide DCP, di-tert-amyl peroxide DTAP, di-tert-butyl peroxide DTBP, tert-amyl hydroperoxide TAHP, tert-butyl hydroperoxide TBHP.

[0012] The organic solvent is one or a combination of several of: methyl isopentanone, butyl acetate, ethyl acetate, propylene glycol monomethyl ether acetate, N,N-dimethylformamide, xylene.

[0013] The present invention chemically modifies an ultraviolet absorber containing a hydroxyl structure, enabling it to have the ability to undergo free radical polymerization without destroying the ultraviolet absorption functional structure, and then uses the modified ultraviolet absorber in the monomer synthesis of coating resins, so that the ultraviolet absorption functional groups can be evenly distributed on the main chain of the macromolecule in the form of chemical bonds.

[0014] The preparation method of its ultraviolet-resistant and anti-aging modified acrylic coating resin includes:

[0015] Step 1: Ultraviolet absorber modification: Mix the acrylic-modified polyisocyanate monomer and the ultraviolet absorber according to a molar ratio of NCO to reactive OH of 1:1. In an organic solvent system, add a catalyst, and react for 1 to 3 hours at 50 - 80 °C and a stirring speed of 300 - 700 r / min in a nitrogen atmosphere. After cooling, a functional monomer containing a double bond structure and ultraviolet absorption functional groups can be prepared.

[0016] Step 2: Uniformly mix the functional monomer prepared in Step 1 with acrylic resin synthesis monomers and a free radical initiator, and slowly and uniformly drip them into a reaction kettle containing an organic solvent. The reaction kettle is under a nitrogen atmosphere, the temperature is controlled at 90 - 150 °C, and the stirring speed is controlled at 600 - 1000 r / min. React for 4 - 8 hours, and after cooling, discharge the product into a storage barrel.

[0017] Step 3: Conduct the following three performance tests on the coating resin prepared in Step 2: (1) Ultraviolet barrier test of the synthesized resin; (2) Compound the coating resin with Bayer curing agent Desmodur N 3900, and conduct a solvent extraction resistance experiment on the cured coating; (3) Coat the compounded coating on a polyurethane film and conduct ultraviolet barrier test, solvent extraction resistance experiment, and aging resistance test.

[0018] The technical effects and advantages of the present invention:

[0019] 1. The coating resin of the present invention itself has excellent weather resistance.

[0020] 2. Using the coating resin prepared by the present invention as the film-forming substance of the coating, it also has the function of blocking ultraviolet rays, and can well protect the plates and films below the coating.

[0021] 3. By using the polymerization method to prepare the intrinsically weather-resistant and ultraviolet-resistant coating film-forming resin, the compatibility between the ultraviolet-resistant small molecule organic matter and the coating resin caused by solvent volatilization can be greatly improved, and problems such as blooming and mildew spots can be solved.

[0022] 4. Since the anti-ultraviolet small molecule organic matter is connected to the main chain of the coating resin by a polymerization method, the coating product maintains a high visible light transmittance, low haze, long-lasting weather resistance, and resistance to organic solvent extraction. Detailed implementation mode

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Embodiment:

[0025] An anti-ultraviolet and anti-aging modified acrylic coating resin, by weight, includes 20 parts of methyl methacrylate, 5 parts of ethyl methacrylate, 5 parts of n-butyl acrylate, 2 parts of lauryl acrylate, 5 parts of 2-hydroxyethyl acrylate, 10 parts of styrene, 6 parts of a reactive functional monomer, 47 parts of an organic solvent, and 0.01 part of benzoyl peroxide.

[0026] Its preparation method is as follows: React 2-(2-isocyanatoethoxy)ethyl methacrylate and 2,2,4,4-tetrahydroxybenzophenone in a molar ratio of 1:1 under the catalysis of organotin in an organic solvent. The total mass ratio of 2-(2-isocyanatoethoxy)ethyl methacrylate and 2,2,4,4-tetrahydroxybenzophenone to the organic solvent and the organotin catalyst is 1:1:0.01 to prepare a reactive functional monomer; by weight, 20 parts of methyl methacrylate, 5 parts of ethyl methacrylate, 5 parts of n-butyl acrylate, 2 parts of lauryl acrylate, 5 parts of 2-hydroxyethyl acrylate, 10 parts of styrene, 6 parts of the reactive functional monomer, 47 parts of the organic solvent, and 0.01 part of benzoyl peroxide. Carry out a free radical polymerization reaction to prepare an anti-ultraviolet and anti-aging modified acrylic coating resin, and then compound the resin with Bayer curing agent Desmodur N 3900 to prepare a coating and carry out coating and curing.

[0027] Comparative example 1:

[0028] By weight, 20 parts of methyl methacrylate, 5 parts of ethyl methacrylate, 5 parts of n-butyl acrylate, 2 parts of lauryl acrylate, 5 parts of 2-hydroxyethyl acrylate, 10 parts of styrene, 53 parts of an organic solvent, and 0.01 part of benzoyl peroxide. Carry out a free radical polymerization reaction to prepare a conventional acrylic coating resin, and then compound the resin with Bayer curing agent Desmodur N3900 to prepare a coating and carry out coating and curing.

[0029] Comparative example 2:

[0030] According to parts by mass, 20 parts of methyl methacrylate, 5 parts of ethyl methacrylate, 5 parts of n-butyl acrylate, 2 parts of lauryl acrylate, 5 parts of 2-hydroxyethyl acrylate, 10 parts of styrene, 53 parts of organic solvent, and 0.01 part of benzoyl peroxide are used. Free radical polymerization reaction is carried out to prepare a conventional acrylic coating resin, and then the resin is compounded with Bayer curing agent Desmodur N3900 and 2,2,4,4-tetrahydroxybenzophenone to prepare a coating and carry out coating and curing.

[0031] Performance tests are carried out:

[0032] Performance 1: Testing the ultraviolet barrier performance of the synthesized resin.

[0033] Sample Ultraviolet blocking rate Synthetic resin in the example 99％ Synthetic resin in Comparative Example 1 46％ Synthetic resin in Comparative Example 2 46％

[0034] Performance 2: Testing the ultraviolet barrier performance of the synthesized resin compounded with a curing agent and the synthesized resin compounded with a curing agent and an ultraviolet absorber after forming a coating.

[0035]

[0036] Performance 3: Testing the weather resistance of the synthesized resin compounded with a curing agent and the synthesized resin compounded with a curing agent and an ultraviolet absorber after forming a coating.

[0037]

[0038] Through the above performance tests, the synthesized resin after modification itself has the performance of blocking ultraviolet rays. At the same time, compared with the coatings prepared by the blending method, it has stronger solvent extraction resistance and better outdoor weather resistance, and can well protect the bottom polymer materials.

[0039] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-ultraviolet and anti-aging modified acrylic coating resin, characterized in that: It includes, by weight parts, 40 - 70 parts of acrylic resin synthesis monomers, 1 - 8 parts of acrylic acid modified polyisocyanate monomers, 1 - 8 parts of ultraviolet absorber containing a hydroxyl structure, 0.01 - 0.1 part of catalyst, 0.01 - 0.5 part of free radical initiator, and 30 - 60 parts of organic solvent.

2. The anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, wherein: The acrylic resin synthesis monomers include one or a combination of several of methyl methacrylate, ethyl methacrylate, ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate, n-octyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, acrylic acid, styrene, vinyl acetate.

3. An anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, characterized in that: The acrylic acid modified polyisocyanate monomers include one or a combination of several of isocyanatoethyl methacrylate, isocyanatoethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2-isocyanato-2-methylpropane-1,3-diyl diacrylate, 2-[O-(1'-methylpropylideneamino)oxycarbonylamino]ethyl methacrylate, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, MOI-DEM, AOI-BM, AOI-BP.

4. The anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, wherein: The ultraviolet absorber containing a hydroxyl structure includes one or a combination of several of 2,4-dihydroxybenzophenone, 2,2,4,4-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone.

5. An anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, characterized in that: The catalyst includes one or a combination of several of tertiary amine catalysts, organotin catalysts, potassium carboxylate catalysts, zinc carboxylate catalysts, bismuth carboxylate catalysts, titanate catalysts.

6. The anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, wherein: The free radical initiator includes one or a combination of several of azobisisobutyronitrile AIBN, azobisisoheptonitrile ADVN, azobisisovaleronitrile AMBN, 1,1’-azo-cyanocyclohexane ACHN, benzoyl peroxide BPO, tert-amyl peroxy-2-ethylhexanoate TAPO, tert-butyl peroxy-2-ethylhexanoate TBPO, tert-amyl peroxyacetate TAPA, tert-amyl peroxybenzoate TAPB, tert-butyl peroxybenzoate TBPB, dicumyl peroxide DCP, di-tert-amyl peroxide DTAP, di-tert-butyl peroxide DTBP, tert-amyl hydroperoxide TAHP, tert-butyl hydroperoxide TBHP.

7. An anti-ultraviolet and anti-aging modified acrylic coating resin according to claim 1, characterized in that: The organic solvent includes one or a combination of several of methyl isopentyl ketone, butyl acetate, ethyl acetate, propylene glycol monomethyl ether acetate, N,N-dimethylformamide, xylene.

8. A method for preparing the ultraviolet-resistant and anti-aging modified acrylic coating resin according to any one of claims 1-7, characterized in that: It includes the following steps: S1: Modification of ultraviolet absorber: Mix the acrylic acid modified polyisocyanate monomer and the ultraviolet absorber according to the molar ratio of NCO to reactive OH of 1:

1. In an organic solvent system, add the catalyst and react. After cooling, a functional monomer containing a double bond structure and a UV absorption functional group can be prepared. S2: uniformly mixing the functional monomer prepared in the above step with the acrylic resin synthesis monomer and the free radical initiator, and slowly dripping the mixture into a reaction kettle containing an organic solvent for reaction, and discharging the mixture after cooling to obtain a coating resin; S3: Performing performance tests on the coating resin prepared in the above steps.

9. The preparation method of the ultraviolet-resistant and anti-aging modified acrylic coating resin according to claim 8, wherein: In step S1, after the catalyst is added, the reaction is carried out in a nitrogen atmosphere at 50 to 80°C and a stirring speed of 300 to 700 r / min for 1 to 3 hours.

10. The preparation method of the ultraviolet-resistant and anti-aging modified acrylic coating resin according to claim 8, characterized in that: In step S2, the reaction conditions of the reactor are: under nitrogen atmosphere, temperature of 90-150° C., stirring speed of 600-1000 r / min, and reaction time of 4-8 hours.

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