Water-based hydroxy acrylic resin as well as preparation method and application thereof

Abstract

The invention discloses water-based hydroxy acrylic resin as well as a preparation method and application thereof, and relates to the technical field of macromolecules. The water-based hydroxy acrylic resin comprises the following reaction raw materials: an acrylate monomer; a hydroxyl acrylate monomer; adding vinyl trimethoxy silane; an initiator; polyether / polyester glycol; a dicyanic acid ester; a chain extender; a catalyst; a neutralizer; water; a cross-linking agent; a leveling agent; an auxiliary agent; the acrylate monomer comprises hydroxypropyl acrylate and methyl crotonate, and the mass ratio of the hydroxypropyl acrylate to the methyl crotonate is 1: (2-4). The water-based hydroxy acrylic resin product is stable in performance, has good weather resistance, water resistance, wear resistance and adhesive force, and can meet the high-performance requirements of automobile coatings. Meanwhile, a water-based system is adopted in the preparation method, VOC emission is reduced, and the environment-friendly requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of polymers, and in particular to a water-based hydroxy acrylic resin and a preparation method and application thereof. Background Art

[0002] With increasingly stringent environmental regulations and consumers' increasing environmental awareness, water-based coatings have attracted much attention due to their low volatile organic compound (VOC) emissions. Water-based hydroxylated acrylic resins and polyurethanes have broad application prospects in the field of automotive coatings due to their excellent weather resistance, water resistance, abrasion resistance and good adhesion. However, the existing water-based hydroxylated acrylic resins and polyurethanes have complex preparation processes, unstable product performance, and are difficult to meet the high performance requirements of automotive coatings. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a water-based hydroxy acrylic resin and a preparation method and application thereof. The water-based hydroxy acrylic resin product of the present invention has stable performance, good weather resistance, water resistance, wear resistance and adhesion, and can meet the high performance requirements of automotive coatings.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] In a first aspect, the present invention provides a water-based hydroxylated acrylic resin, comprising the following reaction raw materials in parts by weight:

[0006] Acrylate monomer 15-26 parts; hydroxy acrylate monomer 12-20 parts; vinyl trimethoxy silane 2-5 parts; initiator 1-3 parts; polyether / polyester diol 4-10 parts; dicyanate 18-25 parts; chain extender 0.5-1 parts; catalyst 0.06-0.1 parts; neutralizer 7-15 parts; water 8-16 parts; crosslinker 0.2-0.5 parts; leveling agent 1-3 parts; additive 3-6 parts;

[0007] The acrylate monomers include hydroxypropyl acrylate and methyl crotonate, and the mass ratio of the hydroxypropyl acrylate to methyl crotonate is 1:(2-4).

[0008] The present invention uses hydroxypropyl acrylate and methyl crotonate as acrylate monomers and compounds them with vinyl trimethoxysilane, which is beneficial to improving the weather resistance, water resistance and adhesion of the water-based hydroxy acrylic resin, so that the water-based hydroxy acrylic resin can be better attached to the substrate. At the same time, by controlling the mass ratio of hydroxypropyl acrylate, methyl crotonate and vinyl trimethoxysilane within the above range, it is beneficial to further improve the performance of the water-based hydroxy acrylic resin.

[0009] Preferably, the hydroxyacrylate monomer is at least one of hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl acrylate.

[0010] Preferably, the initiator includes at least one of tert-butyl peroxide, di-tert-amyl peroxide, benzoyl peroxide, and azobisisobutyronitrile.

[0011] Preferably, the polyether / polyester diol includes at least one of polytetramethylene glycol (PTMG), polyoxypropylene glycol (PPG), polyethylene adipate glycol (PEA), and polyethylene adipate glycol (PDA).

[0012] More preferably, the polyether / polyester diol comprises polytetrahydrofuran diol and polyethylene adipate diol, and the mass ratio of the polytetrahydrofuran diol to polyethylene adipate diol is 1:(2-5).

[0013] The invention is beneficial to further improve the wear resistance and weather resistance of the water-based hydroxy acrylic resin by compounding polytetramethylene glycol and polyethylene adipate glycol in a specific ratio, and is also beneficial to improve the adhesion of the water-based hydroxy acrylic resin.

[0014] Preferably, the dicyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate.

[0015] Preferably, the chain extender is 1,4-butanediol or 2,2-dimethylolpropionic acid.

[0016] Preferably, the catalyst is dibutyltin oxide or dibutyltin dilaurate.

[0017] Preferably, the neutralizing agent includes at least one of aqueous ammonia, N-methyldiethanolamine, N,N-dimethylethanolamine, 2-amino-2-methylpropanol, and N-ethylmorpholine.

[0018] Preferably, the cross-linking agent is hexamethoxymethylolmelamine or butylated melamine.

[0019] Preferably, the auxiliary agent includes at least one of a thickener, a dispersant, a defoaming agent, and a film-forming auxiliary agent.

[0020] In a second aspect, the present invention further provides a method for preparing a water-based hydroxylated acrylic resin, comprising the following steps:

[0021] (1) uniformly mixing an acrylate monomer, a hydroxy acrylate monomer, vinyl trimethoxy silane and an initiator to obtain a monomer mixture;

[0022] (2) mixing a polyether / polyester diol, a dicyanate and a chain extender, adding a catalyst to carry out a prepolymerization reaction, and obtaining a hydroxyl-terminated prepolymer after the reaction;

[0023] (3) adding the monomer mixture to the hydroxyl-terminated prepolymer and mixing them evenly, then adding a neutralizer and water, controlling the pH value to 8-9, and obtaining a water-based hydroxyl acrylic resin emulsion after reaction;

[0024] (4) Add a crosslinking agent, a leveling agent and an auxiliary agent to the water-based hydroxy acrylic resin emulsion, and mix them evenly to obtain a water-based hydroxy acrylic resin.

[0025] In a third aspect, the present invention also provides a use of a water-based hydroxy acrylic resin in an automobile.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The water-based hydroxy acrylic resin product of the present invention has stable performance, good weather resistance, water resistance, wear resistance and adhesion, and can meet the high performance requirements of automotive coatings. At the same time, the preparation method of the present invention adopts a water-based system, reduces VOC emissions, and meets environmental protection requirements. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the protection scope and implementation methods of the present invention are not limited thereto.

[0029] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0030] Polyurethane leveling rheological agent: BYK, BYK333;

[0031] Hydroxyethyl cellulose, model 250HBR, Mairui New Materials;

[0032] Dispersant SDJ8005, Guangdong Dingjia New Material Technology Co., Ltd.;

[0033] Polydimethylsiloxane, Foshan Guirunbao Biotechnology Co., Ltd.;

[0034] Texanol alcohol esters, Eastman.

[0035] The following examples and comparative examples all use the above-mentioned raw materials.

[0036] Example 1

[0037] This embodiment discloses a method for preparing a water-based hydroxylated acrylic resin, comprising the following steps:

[0038] (1) by weight, 15 parts of acrylate monomer, 12 parts of hydroxy acrylate monomer, 2 parts of vinyl trimethoxy silane and 1 part of initiator were mixed uniformly to obtain a monomer mixture;

[0039] The acrylate monomer includes hydroxypropyl acrylate and methyl crotonate, and the mass ratio of hydroxypropyl acrylate to methyl crotonate is 1:3, the hydroxy acrylate monomer is hydroxyethyl methacrylate, and the initiator is tert-butyl peroxide;

[0040] (2) 4 parts of polyether / polyester diol, 18 parts of dicyanate and 0.5 parts of chain extender are mixed, and 0.06 parts of catalyst are added to carry out prepolymerization reaction to obtain a hydroxyl-terminated prepolymer;

[0041] The polyether / polyester diol is polytetramethylene glycol, the dicyanate is toluene diisocyanate, the chain extender is 1,4-butanediol, and the catalyst is dibutyltin oxide;

[0042] (3) adding the monomer mixture to the hydroxyl-terminated prepolymer and mixing evenly, then adding 7 parts of a neutralizing agent and 8 parts of water, controlling the pH value to 8, and obtaining a water-based hydroxyl acrylic resin emulsion after reaction; the neutralizing agent is aqueous ammonia;

[0043] (4) adding 0.2 parts of a crosslinking agent, 1 part of a leveling agent, and 3 parts of an auxiliary agent to the water-based hydroxy acrylic resin emulsion, and mixing them evenly to obtain a water-based hydroxy acrylic resin;

[0044] The cross-linking agent is hexamethoxymethylol melamine, the leveling agent is a polyurethane leveling rheological agent, and the additives include a thickener, a dispersant, a defoaming agent, and a film-forming aid. The mass ratio of the thickener is hydroxyethyl cellulose; the dispersant is dispersant SDJ8005; the defoaming agent is polydimethylsiloxane; and the film-forming aid is Texanol alcohol ester.

[0045] Example 2

[0046] This embodiment discloses a method for preparing a water-based hydroxylated acrylic resin, comprising the following steps:

[0047] (1) By weight, 26 parts of acrylate monomer, 20 parts of hydroxy acrylate monomer, 5 parts of vinyl trimethoxy silane and 5 parts of initiator were mixed uniformly to obtain a monomer mixture;

[0048] The acrylate monomer includes hydroxypropyl acrylate and methyl crotonate, and the mass ratio of hydroxypropyl acrylate to methyl crotonate is 1:2, the hydroxy acrylate monomer is hydroxypropyl acrylate, and the initiator is azobisisobutyronitrile;

[0049] (2) mixing 10 parts of polyether / polyester diol, 25 parts of dicyanate and 1 part of chain extender, adding 0.1 parts of catalyst to carry out prepolymerization reaction, and obtaining a hydroxyl-terminated prepolymer after reaction;

[0050] The polyether / polyester diol is polyethylene adipate diol, the dicyanate is isophorone diisocyanate, the chain extender is 2,2-dimethylol propionic acid, and the catalyst is dibutyltin dilaurate;

[0051] (3) adding the monomer mixture to the hydroxyl-terminated prepolymer and mixing evenly, then adding 15 parts of a neutralizing agent and 16 parts of water, controlling the pH value to 9, and obtaining a water-based hydroxyl acrylic resin emulsion after reaction; the neutralizing agent is aqueous ammonia;

[0052] (4) adding 0.5 parts of a crosslinking agent, 3 parts of a leveling agent, and 6 parts of an auxiliary agent to the water-based hydroxy acrylic resin emulsion, and mixing them evenly to obtain a water-based hydroxy acrylic resin;

[0053] The cross-linking agent is butylated melamine, the leveling agent is a polyurethane leveling rheological agent, and the additives include a thickener, a dispersant, a defoaming agent, and a film-forming aid. The mass ratio of the thickener is hydroxyethyl cellulose; the dispersant is dispersant SDJ8005; the defoaming agent is polydimethylsiloxane; and the film-forming aid is Texanol alcohol ester.

[0054] Example 3

[0055] The difference from Example 1 is that in step (1), the acrylate monomer includes hydroxypropyl acrylate and methyl crotonate, and the mass ratio of hydroxypropyl acrylate to methyl crotonate is 1:4. The rest is the same as Example 1.

[0056] Example 4

[0057] The difference from Example 1 is that in step (2), the polyether / polyester diol includes polytetrahydrofuran diol and polyethylene adipate diol, and the mass ratio of the two is 1:2. The other conditions are the same as those in Example 1.

[0058] Example 5

[0059] The difference from Example 1 is that in step (2), the polyether / polyester diol includes polytetrahydrofuran diol and polyethylene adipate diol, and the mass ratio of the two is 1:3. The rest is the same as Example 1.

[0060] Example 6

[0061] The difference from Example 1 is that in step (2), the polyether / polyester diol includes polytetrahydrofuran diol and polyethylene adipate diol, and the mass ratio of the two is 1:4. The rest is the same as Example 1.

[0062] Example 7

[0063] The difference from Example 1 is that in step (2), the polyether / polyester diol includes polytetrahydrofuran diol and polyethylene adipate diol, and the mass ratio of the two is 1:5. The rest is the same as Example 1.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that in step (1), the acrylate monomer is hydroxypropyl acrylate, and the rest is the same as Example 1.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that in step (1), the acrylate monomer is methyl crotonate, and the rest is the same as Example 1.

[0068] Comparative Example 3

[0069] The difference from Example 1 is that in step (1), no vinyltrimethoxysilane is added, and the rest is the same as Example 1.

[0070] Comparative Example 4

[0071] The difference from Example 1 is that in step (1), the acrylate monomer includes hydroxypropyl acrylate and methyl crotonate, and the mass ratio of hydroxypropyl acrylate to methyl crotonate is 1:1. The rest is the same as Example 1.

[0072] Comparative Example 5

[0073] The difference from Example 1 is that in step (1), the acrylate monomer includes hydroxypropyl acrylate and methyl crotonate, and the mass ratio of hydroxypropyl acrylate to methyl crotonate is 1:5. The rest is the same as Example 1.

[0074] Comparative Example 6

[0075] The difference from Example 1 is that in step (1), ethyl acrylate of equal mass is used to replace hydroxypropyl acrylate, and the rest is the same as Example 1.

[0076] Comparative Example 7

[0077] The difference from Example 1 is that in step (1), methyl crotonate is replaced by ethyl acrylate of equal mass, and the rest is the same as Example 1.

[0078] In order to verify the performance of the water-based hydroxyl acrylic resin of the present invention, the water-based hydroxyl acrylic resin and the water-based isocyanate curing agent (Bayer 3100, Germany) were mixed in a mass ratio of 1:1.5 to prepare a water-based varnish, which was sprayed on tinplate with a coating thickness of 25±um and baked at 60°C for 30 minutes to obtain a pre-coated plate sample for performance evaluation test.

[0079] Performance testing method:

[0080] 1. Neutral salt spray resistance: Tested in accordance with GB / T 1771-2007 Determination of neutral salt spray resistance of paints and varnishes.

[0081] 2. Water resistance: According to GB / T 1733-1993 Determination of water resistance of paint film, the water resistance of the coating film is determined by the immersion test method.

[0082] 3. Abrasion resistance: The surface of the coating was polished with RCA paper tape, produced by Norman Tool Company.

[0083] 4. Adhesion: Tested according to GB / T9286-1998 standard. The lower the adhesion grade, the better the adhesion.

[0084] 5. VOC: Tested in accordance with GB / T23985-2009 standard.

[0085] The performance parameters obtained from the above tests are shown in Table 1-2.

[0086] Table 1

[0087]

[0088]

[0089] Table 2

[0090]

[0091] According to Table 1, the surface of the coating film is flat and smooth, and it is not corroded in the neutral salt spray resistance test, and there is no change in the water resistance test. The wear resistance can reach more than 1400 times, the adhesion level is 0, and the VOC is less than 200g / L, which shows that the water-based hydroxy acrylic resin of the present invention has excellent weather resistance, water resistance, wear resistance and adhesion, and the product performance is stable, which can meet the high performance requirements of automotive coatings. In addition, it meets the requirements of environmental protection.

[0092] According to Comparative Examples 1-3 and 6-7, it can be seen that in Comparative Example 1-2, the acrylic acid ester monomer is solely compounded with hydroxypropyl acrylate or methyl crotonate and vinyl trimethoxysilane, and the weather resistance, water resistance and wear resistance of the coating are not as good as those in Example 1; in Comparative Example 3, no vinyl trimethoxysilane is added, and obvious depressions appear on the surface of the coating, and the weather resistance and water resistance are not as good as those in Example 1; in Comparative Examples 6-7, ethyl acrylate is used to replace hydroxypropyl acrylate or methyl crotonate with an equal mass, and the wear resistance and adhesion of the coating are not as good as those in Example 1, indicating that only when hydroxypropyl acrylate and methyl crotonate are compounded with vinyl trimethoxysilane at the same time, can the water-based hydroxy acrylic resin have excellent weather resistance, water resistance and adhesion, and it is also beneficial to improve the wear resistance of the water-based hydroxy acrylic resin.

[0093] According to Comparative Examples 4-5, the mass ratio of hydroxypropyl acrylate and methyl crotonate in Comparative Examples 4-5 is not within the scope of the present invention, and the wear resistance and adhesion of the coating are not as good as those in Example 1, which shows that the present invention is beneficial to improving the wear resistance and adhesion of the water-based hydroxy acrylic resin by controlling the mass ratio of hydroxypropyl acrylate, methyl crotonate and vinyl trimethoxy silane within the range defined by the present invention.

[0094] According to Examples 4-7, the use of polytetrahydrofuran diol and polyethylene adipate diol in Example 4-7, and controlling the mass ratio of polytetrahydrofuran diol to polyethylene adipate diol to be 1: (2-5) is beneficial to further improve the wear resistance and weather resistance of the water-based hydroxylated acrylic resin.

[0095] 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 the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A water-based hydroxy acrylic resin, characterized in that The reaction materials include the following parts by weight: Acrylate monomer 15-26 parts; hydroxy acrylate monomer 12-20 parts; vinyl trimethoxy silane 2-5 parts; initiator 1-3 parts; polyether / polyester diol 4-10 parts; dicyanate 18-25 parts; chain extender 0.5-1 parts; catalyst 0.06-0.1 parts; neutralizer 7-15 parts; water 8-16 parts; crosslinker 0.2-0.5 parts; leveling agent 1-3 parts; additive 3-6 parts; The acrylate monomers include hydroxypropyl acrylate and methyl crotonate, and the mass ratio of the hydroxypropyl acrylate to methyl crotonate is 1:(2-4).

2. The water-based hydroxy acrylic resin according to claim 1, characterized in that The polyether / polyester diol includes at least one of polytetramethylene glycol, polyoxypropylene glycol, polyethylene adipate glycol, and polyethylene adipate glycol ether.

3. The water-based hydroxy acrylic resin according to claim 2, characterized in that The polyether / polyester diols include polytetramethylene glycol and polyethylene adipate glycol.

4. The water-based hydroxy acrylic resin according to claim 3, characterized in that The mass ratio of the polytetrahydrofuran diol to the polyethylene adipate diol is 1:(2-5).

5. The water-based hydroxy acrylic resin according to claim 1, characterized in that The initiator includes at least one of tert-butyl peroxide, di-tert-amyl peroxide, benzoyl peroxide, and azobisisobutyronitrile.

6. The water-based hydroxy acrylic resin according to claim 1, characterized in that At least one of (a) to (e): (a) the hydroxy acrylate monomer is at least one of hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl acrylate; (b) the chain extender is 1,4-butanediol or 2,2-dimethylolpropionic acid; (c) the catalyst is dibutyltin oxide or dibutyltin dilaurate; (d) the neutralizing agent comprises at least one of aqueous ammonia, N-methyldiethanolamine, N,N-dimethylethanolamine, 2-amino-2-methylpropanol, and N-ethylmorpholine; (e) The cross-linking agent is hexamethoxymethylolmelamine or butylated melamine.

7. The water-based hydroxy acrylic resin according to claim 1, characterized in that The dicyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate.

8. The water-based hydroxy acrylic resin according to claim 1, characterized in that The auxiliary agent includes at least one of a thickener, a dispersant, a defoaming agent, and a film-forming auxiliary agent.

9. The method for preparing the water-based hydroxy acrylic resin according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) uniformly mixing an acrylate monomer, a hydroxy acrylate monomer, vinyl trimethoxy silane and an initiator to obtain a monomer mixture; (2) mixing a polyether / polyester diol, a dicyanate and a chain extender, adding a catalyst to carry out a prepolymerization reaction, and obtaining a hydroxyl-terminated prepolymer after the reaction; (3) adding the monomer mixture to the hydroxyl-terminated prepolymer and mixing them evenly, then adding a neutralizer and water, controlling the pH value to 8-9, and obtaining a water-based hydroxyl acrylic resin emulsion after reaction; (4) Add a crosslinking agent, a leveling agent and an auxiliary agent to the water-based hydroxy acrylic resin emulsion, and mix them evenly to obtain a water-based hydroxy acrylic resin.

10. Use of the water-based hydroxy acrylic resin as claimed in claim 9 in automobiles.

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