Epoxy resin modified waterborne acrylic resin dispersion and preparation method thereof

Abstract

The present invention belongs to the field of polymer material synthesis, and relates to an epoxy resin modified water-based acrylic resin dispersion and a preparation method. The epoxy resin modified water-based acrylic resin dispersion comprises the following raw materials: epoxy resin, diol, hydrophilic monomer, methacrylate glycidyl ether, tertiary amine catalyst, vinyl soft monomer, vinyl hard monomer, functional monomer, vinyl organosiloxane, solvent, initiator, neutralizer, chain transfer agent and deionized water. The water-based acrylic resin dispersion and its downstream product water-based acrylic industrial coating prepared by using the above monomers as raw materials and semi-continuous seed free radical polymerization process have the characteristics of good optical properties, fast drying speed, excellent water resistance and salt spray resistance, high hardness, etc. The product is green and environmentally friendly, with moderate cost, in line with the development trend of the industry, and has broad application prospects in the fields of electronic devices, optoelectronic materials, nano-composite materials, etc.

Description

Technical Field

[0001] The invention belongs to the field of polymer material synthesis and relates to an epoxy resin modified waterborne acrylic resin dispersion and a preparation method thereof. Background Art

[0002] As environmental problems become increasingly severe, people have higher and higher requirements for the environmental friendliness of materials, especially in the field of coatings. A number of policies have been introduced to restrict the production and use of oil-based coatings and promote the development of water-based coatings, powder coatings, and high-solid content coatings. Compared with traditional oil-based coatings, the dispersion medium of water-based epoxy-modified acrylic resin coatings is water, which can effectively reduce the emission of VOCs during the production and use of coatings, thereby achieving the purpose of protecting the environment. At the same time, the use of water-based coatings also improves the construction environment of workers and improves the transportation and storage safety of coatings.

[0003] Waterborne acrylic paint refers to a type of environmentally friendly paint that uses acrylic resin or modified acrylic resin as a film-forming material. It has the advantages of good weather resistance, fast drying speed, light color, and good gloss retention. It is widely used in transportation, construction and home decoration, agricultural machinery, mining equipment and other fields. However, the water-borne acrylic resin and its downstream acrylic paint products on the market currently need to be further improved in terms of water resistance and storage stability during the application process, and most water-borne acrylic paint products require the addition of emulsifiers, which seriously affects their adhesion, gloss and salt spray resistance. Therefore, it is urgent to develop water-borne acrylic resins and their preparation processes with good comprehensive performance, moderate cost, and easy industrial production to meet the application of water-borne acrylic paints in electronic devices, optoelectronic materials, nanocomposites, industrial corrosion protection and other fields. Summary of the invention

[0004] The present invention proposes an epoxy resin modified water-based acrylic resin dispersion and a preparation method thereof. By grafting epoxy structural units on the acrylic resin molecular chain, the adhesion and salt spray resistance of the acrylic resin are improved, thereby solving the problem that the traditional acrylic coating has poor adhesion and insufficient salt spray resistance on metal substrates. When preparing the epoxy resin prepolymer, dimethylol propionic acid or dimethylol butyric acid with strong hydrophilicity is introduced through polycondensation to achieve the water dispersibility of the resin, thereby solving the problem that the traditional water-based acrylic coating needs to add an emulsifier to achieve the effect of stable dispersion, thereby improving the storage stability of the resin dispersion and downstream coating products. The introduction of an organic siloxane system solves the problem that the traditional acrylic coating has poor wettability with inorganic pigments and fillers, while also improving the water resistance and mechanical properties of the coating. The introduction of a bisphenol fluorene structure improves the hardness and optical properties of the coating. Finally, the comprehensive properties of the coating, such as mechanical properties, water resistance, solvent resistance, and weather resistance, are simultaneously improved.

[0005] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight: 92-127 parts of epoxy resin, 56-122 parts of diol, 39-77 parts of hydrophilic monomer, 18.5-31.3 parts of glycidyl methacrylate, 0.8-2.2 parts of tertiary amine catalyst, 100-327 parts of vinyl soft monomer, 86-375 parts of vinyl hard monomer, 30-75 parts of functional monomer, 20-45 parts of vinyl organosiloxane, 80-396 parts of solvent, 4-21 parts of initiator, 11-47 parts of neutralizer, 0.5-6 parts of chain transfer agent and deionized water.

[0007] The epoxy value of the epoxy resin used to prepare the epoxy resin modified waterborne acrylic resin dispersion is 0.35-0.55 mol / 100g, preferably BE-188EL or Sanmu brand E-51 epoxy resin.

[0008] The diol used to prepare the epoxy resin modified waterborne acrylic resin dispersion is bisphenol fluorene.

[0009] The hydrophilic monomer for preparing the epoxy resin modified waterborne acrylic resin dispersion is one or a combination of 2,2-dihydroxymethylpropionic acid and 2,2-dihydroxymethylbutyric acid; and the tertiary amine catalyst is selected from tetrabutylammonium bromide.

[0010] The vinyl soft monomer used to prepare the epoxy resin modified water-based acrylic resin dispersion is selected from one or any combination of butyl methacrylate, butyl acrylate, n-octyl acrylate, lauryl acrylate, isooctyl acrylate, vinyl acetate, isooctyl methacrylate, and n-octyl methacrylate; the vinyl hard monomer is selected from one or any combination of methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, benzyl acrylate, phenyl acrylate, styrene, divinylbenzene, and acrylonitrile.

[0011] The functional monomer for preparing the epoxy resin modified waterborne acrylic resin dispersion is selected from at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; the vinyl organosiloxane is one or a combination of two of vinyl triisopropoxy silane, vinyl tri(β-methoxyethoxy) silane or γ-methacryloxypropyl trimethoxy silane.

[0012] The initiator for preparing the epoxy resin modified waterborne acrylic resin dispersion is at least one of tert-butyl perbenzoate, di-tert-butyl peroxide or di-tert-amyl peroxide; and the chain transfer agent is n-dodecyl mercaptan.

[0013] The solvent for preparing the epoxy resin modified waterborne acrylic resin dispersion is a combination of propylene glycol methyl ether and n-butanol, propylene glycol monobutyl ether, and dimethyl succinate.

[0014] The neutralizing agent for preparing the epoxy resin modified waterborne acrylic resin dispersion is at least one of triethylamine, N,N-dimethylethanolamine or 2-amino-2-methyl-1-propanol.

[0015] The preparation method of the epoxy resin modified waterborne acrylic resin dispersion comprises the following steps:

[0016] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. When the temperature is stable, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 120-160°C and react for 2-4 hours.

[0017] (2) slowly adding glycidyl methacrylate, controlling the addition time to 20-30 min, and then continuing the reaction for 2-3 h to obtain an epoxy resin prepolymer;

[0018] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0019] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 85-95°C, adding a co-solvent and stirring at a constant temperature for 20-30 minutes until the mixture is uniformly mixed; then heating to 130-150°C, dripping the monomer mixture in step (3), controlling the total dripping time to be 3.5-5.5 hours, and keeping the temperature for 3-5 hours after the dripping is completed, to obtain an epoxy resin-modified waterborne acrylic resin;

[0020] (5) Cooling the epoxy resin modified waterborne acrylic resin obtained in step (4) to 60-70° C., adding a neutralizing agent, adjusting the pH of the system to between 7.5 and 8.5, rapidly stirring for 20-35 min, then slowly adding deionized water for high-speed dispersion for 1-1.5 h, filtering, and obtaining an epoxy resin modified waterborne acrylic resin dispersion with a solid content of 35-45%.

[0021] The beneficial effects of the present invention are as follows: the present invention utilizes the characteristics of methacrylate glycidyl ether having an active double bond at one end and a highly active epoxy ring at the other end, and the epoxy ring of methacrylate glycidyl ether undergoes a ring-opening esterification reaction with the hydroxyl or carboxyl group on the epoxy resin, so that the active double bond on methacrylate glycidyl ether can be introduced into the molecular structure of the epoxy resin, thereby improving the copolymerization ability with the acrylic monomer and solving the problem of low grafting rate of epoxy resin on the acrylic resin molecular chain; by introducing dimethylol propionic acid or dimethylol butyric acid to modify the epoxy resin, a hydrophilic structural unit is introduced into the epoxy resin molecular chain, so that the finally prepared epoxy resin modified acrylic resin has a certain hydrophilicity, and can achieve self-emulsification without the need for an external emulsifier, thereby solving the problems of poor water resistance, salt spray resistance and adhesion of traditional water-based acrylic resins caused by emulsification. In the resin preparation process, by introducing organic siloxane modification, the wetting and dispersibility of the resin and the pigment filler are improved, and the storage stability of the final coating product is improved. This modification method is not only energy-saving and environmentally friendly, but also has moderate cost. The equipment for producing the resin is relatively simple, convenient for industrial production, and has a good application market. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is the infrared curve of the dispersion coating prepared in Example 1 of the present invention.

[0024] Figure 2 This is a thermal gravimetric test curve of the dispersion coating film prepared in Example 1 of the present invention.

[0025] Figure 3 This is the DSC test chart of the dispersion coating film prepared in Example 1 of the present invention.

[0026] Figure 4 This is the gel permeation chromatography curve of the dispersion coating prepared in Example 1 of the present invention.

[0027] Figure 5 The particle size test results of the dispersion prepared in Example 1 of the present invention are shown.

[0028] Figure 6 This is a graph showing the particle size test results of the dispersion prepared in Example 2 of the present invention.

[0029] Figure 7 This is a graph showing the particle size test results of the dispersion prepared in Example 3 of the present invention.

[0030] Figure 8 This is a graph showing the particle size test results of the dispersion prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction 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 are within the scope of protection of the present invention.

[0032] Example 1

[0033] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight:

[0034] Epoxy resin: Sanmu 128 epoxy resin, 103 parts;

[0035] Diol: bisphenol fluorene, 91 parts;

[0036] Hydrophilic monomers: 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid account for 17 and 40 parts respectively;

[0037] Glycidyl methacrylate: 25 parts;

[0038] Tertiary amine catalyst: tetrabutylammonium bromide, 1.8 parts;

[0039] Vinyl soft monomer: butyl acrylate and n-octyl acrylate, accounting for 147 and 150 parts respectively;

[0040] Vinyl hard monomers: methyl methacrylate and styrene, accounting for 125 and 160 parts respectively;

[0041] Functional monomer: hydroxypropyl acrylate, 52 parts;

[0042] Vinyl organosiloxane: vinyl triisopropoxysilane, 23 parts;

[0043] Initiator: di-tert-butyl peroxide, 14 parts;

[0044] Solvent: propylene glycol methyl ether, n-butanol, accounting for 134 and 80 parts respectively;

[0045] Chain transfer agent: n-dodecyl mercaptan, 4.6 parts;

[0046] Dispersant: deionized water, 671 parts;

[0047] Neutralizer: N,N-dimethylethanolamine, 39.6 parts.

[0048] The preparation process of the epoxy resin modified waterborne acrylic resin dispersion is as follows:

[0049] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. After the temperature stabilizes, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 130°C and react for 3.5 hours.

[0050] (2) slowly adding glycidyl methacrylate, controlling the addition time to 30 min, and then continuing the reaction for 3 h to obtain an epoxy resin prepolymer;

[0051] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0052] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 90°C, adding a co-solvent and stirring at a constant temperature for 30 minutes until the mixture is uniformly mixed; then raising the temperature to 145°C, dripping the monomer mixture obtained in step (3), controlling the total dripping time to be 5 hours, and keeping the temperature for 4 hours after the dripping is completed, to obtain an epoxy resin modified waterborne acrylic resin;

[0053] (5) The epoxy resin modified waterborne acrylic resin obtained in step (4) was cooled to 70° C., a neutralizing agent was added, the pH of the system was adjusted to between 8.5, and the mixture was rapidly stirred for 35 min. Then, deionized water was slowly added and dispersed at high speed for 1 h. The mixture was filtered to obtain an epoxy resin modified waterborne acrylic resin dispersion having a solid content of 42%.

[0054] The epoxy resin modified waterborne acrylic resin dispersion prepared in Example 1 was dehydrated and dried, and infrared spectroscopy (FT-IR) was performed. The results are shown in Figure 1 , 2927 cm in the infrared spectrum -1 and 2855cm -1 The CH stretching vibration absorption peak is 1727cm -1 is the C=O stretching vibration absorption peak, 1605 cm -1 and 1509cm -1 The peak at is the characteristic absorption peak of the stretching vibration of the carbon skeleton of the benzene ring, indicating that the epoxy resin used in the present invention contains bisphenol A epoxy resin. Figure 2 This is a thermogravimetric test curve of the dispersion coating prepared in this example after drying. It can be seen from the figure that the resin has good thermal stability below 355°C. Figure 3 From the DSC curve of the dispersion resin coating after drying, it can be seen that the glass transition temperature of the resin is around -13°C, it has good flexibility, and effectively improves the phenomenon of the coating becoming brittle when cooled. Figure 4From the GPC curve of the prepared dispersion, it can be seen that the Mn of the prepared resin is 5633 and the Mw is 41887. It is a broad distribution resin. Such a molecular weight design is not only beneficial to the construction and leveling of downstream products, but also can ensure the mechanical properties of the coating. Figure 5 The particle size distribution of the dispersion prepared for this example shows that the particle size distribution of the prepared dispersion is uniform, with 90% of the particle sizes being below 183 nm, which is beneficial to the stable storage of the dispersion and subsequent coating.

[0055] Example 2

[0056] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight:

[0057] Epoxy resin: BE188EL epoxy resin, 92 parts;

[0058] Diol: bisphenol fluorene, 58 parts;

[0059] Hydrophilic monomer: 2,2-dimethylolpropionic acid, 40 parts;

[0060] Glycidyl methacrylate: 18.5 parts;

[0061] Tertiary amine catalyst: tetrabutylammonium bromide, 1 part;

[0062] Vinyl soft monomer: butyl acrylate and lauryl acrylate, accounting for 65 parts and 58 parts respectively;

[0063] Vinyl hard monomer: methyl methacrylate and styrene, accounting for 70 parts and 16 parts respectively;

[0064] Functional monomer: hydroxyethyl acrylate, 30 parts;

[0065] Vinyl organosiloxane: γ-methacryloxypropyltrimethoxysilane, 20 parts;

[0066] Initiator: tert-butyl perbenzoate, di-tert-butyl peroxide, 4, 2 parts;

[0067] Solvent: propylene glycol methyl ether, propylene glycol monobutyl ether, accounting for 100 parts and 58 parts respectively;

[0068] Chain transfer agent: n-dodecyl mercaptan, 1.5 parts;

[0069] Dispersant: deionized water, 422 parts;

[0070] Neutralizing agent: triethylamine, 28 parts.

[0071] The preparation process of the epoxy resin modified waterborne acrylic resin dispersion is as follows:

[0072] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. When the temperature is stable, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 160°C and react for 2 hours.

[0073] (2) slowly adding glycidyl methacrylate, controlling the addition time to 20 min, and then continuing the reaction for 2.5 h to obtain an epoxy resin prepolymer;

[0074] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0075] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 95°C, adding a co-solvent and stirring at a constant temperature for 20 minutes until the mixture is uniformly mixed; then heating to 135°C, dripping the monomer mixture in step (3), controlling the total dripping time to be 3.5 hours, and keeping the temperature for 5 hours after the dripping is completed, to obtain an epoxy resin-modified waterborne acrylic resin;

[0076] (5) The epoxy resin modified waterborne acrylic resin obtained in step (4) was cooled to 60° C., a neutralizing agent was added, the pH of the system was adjusted to between 7.5, and the mixture was rapidly stirred for 30 min. Then, deionized water was slowly added and dispersed at high speed for 1.5 h. The mixture was filtered to obtain an epoxy resin modified waterborne acrylic resin dispersion having a solid content of 45%.

[0077] The particle size distribution of the dispersion prepared in this example is as follows Figure 6 , it can be seen that the particle size distribution of the dispersion is relatively uniform, and 90% of the particle size is below 186nm.

[0078] Example 3

[0079] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight:

[0080] Epoxy resin: BE188EL epoxy resin, 127 parts;

[0081] Diol: bisphenol fluorene, 110 parts;

[0082] Hydrophilic monomer: 2,2-dimethylolbutyric acid, 75 parts;

[0083] Glycidyl methacrylate: 31.3 parts;

[0084] Tertiary amine catalyst: tetrabutylammonium bromide, 2.2 parts;

[0085] Vinyl soft monomer: isooctyl methacrylate and lauryl acrylate, accounting for 173 parts and 130 parts respectively;

[0086] Vinyl hard monomer: methyl methacrylate, phenyl acrylate, accounting for 200 parts and 175 parts respectively;

[0087] Functional monomers: hydroxyethyl acrylate, hydroxypropyl acrylate, 35 parts and 40 parts respectively;

[0088] Vinyl organosiloxane: γ-methacryloxypropyltrimethoxysilane, 43 parts;

[0089] Initiator: tert-butyl perbenzoate, 21 parts;

[0090] Solvent: propylene glycol methyl ether, propylene glycol monobutyl ether, accounting for 220 parts and 168 parts respectively;

[0091] Chain transfer agent: n-dodecyl mercaptan, 6 parts;

[0092] Dispersant: deionized water, 1773 parts;

[0093] Neutralizing agent: N,N-dimethylethanolamine, 53 parts.

[0094] The preparation process of the epoxy resin modified waterborne acrylic resin dispersion is as follows:

[0095] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. When the temperature is stable, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 120°C and react for 4 hours.

[0096] (2) slowly adding glycidyl methacrylate, controlling the dropping time to 30 min, and then continuing the reaction for 2 h to obtain an epoxy resin prepolymer;

[0097] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0098] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 85°C, adding a co-solvent and stirring at a constant temperature for 30 minutes until the mixture is uniformly mixed; then heating to 130°C, dripping the monomer mixture in step (3), controlling the total dripping time to be 5.5 hours, and keeping the temperature for 3 hours after the dripping is completed to obtain an epoxy resin-modified waterborne acrylic resin;

[0099] (5) The epoxy resin modified waterborne acrylic resin obtained in step (4) was cooled to 65° C., a neutralizing agent was added, the pH of the system was adjusted to between 8.0, and the mixture was rapidly stirred for 35 min. Then, deionized water was slowly added and dispersed at high speed for 1.5 h. The mixture was filtered to obtain an epoxy resin modified waterborne acrylic resin dispersion having a solid content of 35%.

[0100] The particle size distribution of the dispersion prepared in this example is as follows Figure 7 , it can be seen that the particle size distribution of the dispersion is relatively uniform, with 90% of the particle size distribution below 179nm.

[0101] Example 4

[0102] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight:

[0103] Epoxy resin: Sanmu brand 128 epoxy resin, 110 parts;

[0104] Diol: bisphenol fluorene, 94 parts;

[0105] Hydrophilic monomer: 25 parts of 2,2-dimethylolpropionic acid and 31 parts of 2,2-dimethylolbutanoic acid, respectively;

[0106] Glycidyl methacrylate: 27 parts;

[0107] Tertiary amine catalyst: tetrabutylammonium bromide, 1.5 parts;

[0108] Vinyl soft monomer: isooctyl methacrylate and butyl acrylate, accounting for 93 parts and 59 parts respectively;

[0109] Vinyl hard monomer: methyl methacrylate, methyl acrylate, acrylonitrile, accounting for 57 parts, 75 parts, and 63 parts respectively;

[0110] Functional monomer: hydroxypropyl acrylate, 52 parts;

[0111] Vinyl organosiloxane: vinyl tris(β-methoxyethoxy)silane, 35 parts;

[0112] Initiator: tert-butyl perbenzoate, 13.8 parts;

[0113] Solvent: propylene glycol monobutyl ether, 245 parts;

[0114] Chain transfer agent: n-dodecyl mercaptan, 6 parts;

[0115] Dispersant: deionized water, 953 parts;

[0116] Neutralizing agent: N,N-dimethylethanolamine and triethylamine, accounting for 18 and 21 parts respectively.

[0117] The preparation process of the epoxy resin modified waterborne acrylic resin dispersion is as follows:

[0118] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. After the temperature stabilizes, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 140°C and react for 3 hours.

[0119] (2) slowly adding glycidyl methacrylate, controlling the addition time to 25 min, and then continuing the reaction for 2.5 h to obtain an epoxy resin prepolymer;

[0120] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0121] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 95°C, adding a co-solvent and stirring at a constant temperature for 25 minutes until the mixture is uniformly mixed; then heating to 140°C, dripping the monomer mixture obtained in step (3), controlling the total dripping time to be 4.8 hours, and keeping the temperature for 3.7 hours to obtain an epoxy resin-modified waterborne acrylic resin;

[0122] (5) The epoxy resin modified waterborne acrylic resin obtained in step (4) was cooled to 70° C., a neutralizing agent was added, the pH of the system was adjusted to between 8.4, and the mixture was rapidly stirred for 20 min. Then, deionized water was slowly added and dispersed at high speed for 1 h. The mixture was filtered to obtain an epoxy resin modified waterborne acrylic resin dispersion having a solid content of 38%.

[0123] The particle size distribution of the dispersion prepared in this example is as follows Figure 8 , it can be seen that the particle size distribution of the dispersion is relatively uniform, with 90% of the particle size distribution below 178nm.

[0124] Example 5

[0125] An epoxy resin modified waterborne acrylic resin dispersion comprises the following raw materials in parts by weight:

[0126] Epoxy resin: BE188EL epoxy resin, 98 parts;

[0127] Diol: bisphenol fluorene, 92 parts;

[0128] Hydrophilic monomer: 2,2-dimethylolpropionic acid, 64 parts;

[0129] Glycidyl methacrylate: 30 parts;

[0130] Tertiary amine catalyst: tetrabutylammonium bromide, 1.7 parts;

[0131] Vinyl soft monomer: butyl methacrylate and butyl acrylate, accounting for 93 parts and 79 parts respectively;

[0132] Vinyl hard monomers: methyl methacrylate and acrylonitrile, accounting for 140 parts and 63 parts respectively;

[0133] Functional monomer: hydroxypropyl methacrylate, 55 parts;

[0134] Vinyl organosiloxane: vinyl tris(β-methoxyethoxy)silane, 42 parts;

[0135] Initiator: tert-butyl perbenzoate, 19 parts;

[0136] Solvent: propylene glycol methyl ether, 261 parts;

[0137] Chain transfer agent: n-dodecyl mercaptan, 4 parts;

[0138] Dispersant: deionized water, 857 parts;

[0139] Neutralizer: N,N-dimethylethanolamine, 45 parts.

[0140] The preparation process of the epoxy resin modified waterborne acrylic resin dispersion is as follows:

[0141] (1) Weigh the epoxy resin according to the formula and place it in a reactor at 100°C. Replace the air in the reactor with N2. When the temperature is stable, add diol, hydrophilic monomer and tertiary amine catalyst. Heat the reactor to 120°C and react for 4 hours.

[0142] (2) slowly adding glycidyl methacrylate, controlling the dropping time to 30 min, and then continuing the reaction for 2 h to obtain an epoxy resin prepolymer;

[0143] (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture;

[0144] (4) Cooling the epoxy resin prepolymer obtained in step (2) to 85°C, adding a co-solvent and stirring at a constant temperature for 30 minutes until the mixture is uniformly mixed; then heating to 130°C, dripping the monomer mixture in step (3), controlling the total dripping time to be 5.5 hours, and keeping the temperature for 3 hours after the dripping is completed to obtain an epoxy resin-modified waterborne acrylic resin;

[0145] (5) The epoxy resin modified waterborne acrylic resin obtained in step (4) was cooled to 70° C., a neutralizing agent was added, the pH of the system was adjusted to between 8.4, and the mixture was rapidly stirred for 20 min. Then, deionized water was slowly added and dispersed at high speed for 1 h. The mixture was filtered to obtain an epoxy resin modified waterborne acrylic resin dispersion having a solid content of 41%.

[0146] To further illustrate the epoxy resin modified waterborne acrylic resin dispersion disclosed in the present invention, the present invention also conducted corresponding tests on the epoxy resin modified waterborne acrylic resin dispersion and coating film prepared in Examples 1 to 5, and the test method is as follows:

[0147] Dispersion particle size test: The epoxy resin-modified waterborne acrylic resin dispersion was diluted into deionized water, and the dispersion particle size and its distribution were tested using a laser particle size analyzer.

[0148] Resin storage and transportation stability test: Place the epoxy resin modified water-based acrylic resin dispersion sample in a 50°C oven and keep it at a constant temperature for 1 month. Take it out and place it at room temperature for observation. If no gel or separation occurs, it passes the test.

[0149] Determination of adhesion of resin coating film: The adhesion of the dispersion coating film prepared in the example was measured according to the method of GB / T9286-1998.

[0150] Determination of surface drying time and actual drying time of coating film: The epoxy resin-modified water-based acrylic resin dispersion prepared in the example was evenly applied on a polytetrafluoroethylene plate, dried at a constant temperature of 25°C, and the surface drying time and actual drying time of the coating film were determined according to the method of GB1728-79.

[0151] Resin coating film hardness test: According to GB / T6739-2006 standard, the pencil method is used to measure the hardness of the coating film.

[0152] Resin coating salt spray resistance test: GB / T1771-2007 standard is used to test the neutral salt spray resistance of the resin coating. The paint film is considered to have passed the test if there is no bubbling or peeling for 240 hours and slight discoloration is allowed.

[0153] Resin coating water resistance test: The water resistance of resin coating is tested using the method of GB / T1733-1993. If the paint film does not bubble or fall off for 240 hours and slight discoloration is allowed, it is considered to have passed the test.

[0154]

[0155] 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. An epoxy resin modified waterborne acrylic resin dispersion, characterized in that: The invention comprises the following raw materials in parts by weight: 92-127 parts of epoxy resin, 56-122 parts of diol, 39-77 parts of hydrophilic monomer, 18.5-31.3 parts of glycidyl methacrylate, 0.8-2.2 parts of tertiary amine catalyst, 100-327 parts of vinyl soft monomer, 86-375 parts of vinyl hard monomer, 30-75 parts of functional monomer, 20-45 parts of vinyl organosiloxane, 80-396 parts of solvent, 4-21 parts of initiator, 11-47 parts of neutralizer, 0.5-6 parts of chain transfer agent and deionized water; The vinyl soft monomer is selected from one or any combination of butyl methacrylate, butyl acrylate, n-octyl acrylate, lauryl acrylate, isooctyl acrylate, vinyl acetate, isooctyl methacrylate, n-octyl methacrylate; the vinyl hard monomer is selected from one or any combination of methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, benzyl acrylate, phenyl acrylate, styrene, divinyl benzene, acrylonitrile; The functional monomer is selected from at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; the vinyl organosiloxane is one or a combination of two of vinyl triisopropoxy silane, vinyl tri(β-methoxyethoxy) silane or γ-methacryloxypropyl trimethoxy silane; The preparation method of the epoxy resin modified waterborne acrylic resin dispersion comprises the following steps: (1) Weighing epoxy resin according to the formula, placing it in a reactor at 100° C., replacing the air in the reactor with N2, and adding diol, hydrophilic monomer and tetrabutylammonium bromide after the temperature stabilizes, and reacting in the reactor; the hydrophilic monomer is one or a combination of 2,2-dihydroxymethylpropionic acid and 2,2-dihydroxymethylbutyric acid; (2) slowly adding glycidyl methacrylate, controlling the adding time, and then continuing the reaction to obtain an epoxy resin prepolymer; (3) Weighing a vinyl soft monomer, a vinyl hard monomer, a functional monomer, a vinyl organosiloxane, an initiator and a chain transfer agent according to the formula, and mixing them uniformly by ultrasonication to obtain a monomer mixture; (4) cooling the epoxy resin prepolymer obtained in step (2), adding a solvent and stirring at a constant temperature until the mixture is uniformly mixed; then raising the temperature, dripping the monomer mixture obtained in step (3), controlling the total dripping time, and maintaining the temperature until the dripping is complete, thereby obtaining an epoxy resin modified waterborne acrylic resin; (5) Cooling the epoxy resin modified waterborne acrylic resin obtained in step (4), adding a neutralizing agent, adjusting the pH of the system, rapidly stirring, then slowly adding deionized water for high-speed dispersion, and filtering to obtain an epoxy resin modified waterborne acrylic resin dispersion with a solid content of 35-45%.

2. The epoxy resin modified waterborne acrylic resin dispersion according to claim 1, characterized in that: In the step (1), the epoxy value of the epoxy resin is 0.35-0.55 mol / 100 g; and the diol is bisphenol fluorene.

3. The epoxy resin modified waterborne acrylic resin dispersion according to claim 1, characterized in that: In step (1), the reaction temperature in the reactor is 120-160° C., and the reaction time is 2-4 hours. In step (2), the dropwise addition time is 20-30 minutes, and the continued reaction time is 2-3 hours.

4. The epoxy resin modified waterborne acrylic resin dispersion according to claim 1, characterized in that: In the step (3), the initiator is at least one of tert-butyl perbenzoate, di-tert-butyl peroxide or di-tert-amyl peroxide; and the chain transfer agent is n-dodecyl mercaptan.

5. The epoxy resin modified waterborne acrylic resin dispersion according to claim 1, characterized in that: In the step (4), the solvent is a combination of propylene glycol methyl ether and one or more of n-butanol, propylene glycol monobutyl ether, and dimethyl succinate; the epoxy resin prepolymer is cooled to 85-95°C, the constant temperature stirring time is 20-30 minutes, the heating temperature is 130-150°C, the dropwise addition time is 3.5-5.5 hours, and the heat preservation time is 3-5 hours.

6. The epoxy resin modified waterborne acrylic resin dispersion according to claim 1, characterized in that: In the step (5), the neutralizing agent is at least one of triethylamine, N,N-dimethylethanolamine or 2-amino-2-methyl-1-propanol; the cooling temperature is 60-70° C., the pH of the system is adjusted to 7.5-8.5, the rapid stirring time is 20-35 minutes, and the high-speed dispersion time is 1-1.5 hours.

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