WO2017020513A1

WO2017020513A1 - Hydroxyl polyacrylate emulsion and preparation method and application thereof

Info

Publication number: WO2017020513A1
Application number: PCT/CN2015/099289
Authority: WO
Inventors: 瞿金清; 段晓俊; 朱延安
Original assignee: 华南理工大学; 嘉宝莉化工集团股份有限公司
Priority date: 2015-07-31
Filing date: 2015-12-28
Publication date: 2017-02-09
Also published as: CN105061665B; CN105061665A

Abstract

The present invention discloses a hydroxyl polyacrylate emulsion and preparation method and application thereof. The preparation method comprises: weighing an acrylate monomer and/or methacrylate monomer, a hydroxyl acrylate monomer, an acrylic acid monomer, an acrylate functional monomer and a hydroxyl oligomer, mixing uniformly to prepare a monomer mixture, and taking 10-15% of the monomer mixture to emulsify with an emulsifier, so as to prepare a seed pre-emulsion; adding the emulsifier, sodium bicarbonate and deionized water into a reactor, stirring, increasing the temperature of the reaction system, adding an initiator, stabilizing, adding all of the seed pre-emulsion drop-wise, stabilizing, adding the remaining monomer mixture and initiator drop-wise, increasing the temperature, ageing, lowering the temperature, neutralizing, remaining the temperature, and then cooling to obtain the hydroxyl polyacrylate emulsion. A coating film of an aqueous dual component polyurethane coating prepared from the hydroxyl polyacrylate emulsion and an aqueous polyisocyanate curing agent has superior hardness, luster and durability to chemicals.

Description

Hydroxy polyacrylate emulsion and preparation method and application thereof

Technical field

The invention relates to an aqueous two-component polyurethane coating, in particular to a hydroxy polyacrylate emulsion and a preparation method and application thereof.

Background technique

Most of the existing wood coatings are solvent-based coatings, containing more than 50% of organic solvents. These solvents will volatilize into the atmosphere during the construction process, and also damage human health, and the organic solvents themselves will cause such as burning, explosion, etc. Security risks. Therefore, the water-based coating of wood coatings is a trend in the development of international coatings. Waterborne wood coatings include one-component and two-component waterborne wood coatings. Among them, the paint properties of single-component waterborne wood coatings include poor water resistance, chemical resistance and hardness, and the gap with oily coatings is large, which severely limits the promotion and application of waterborne wood coatings. The mechanical properties, water resistance and chemical resistance of the two-component waterborne wood coating are comparable to those of the solvent-based wood coating, which can overcome the shortcomings of the one-component waterborne wood coating. In January 2015, China has issued a decree on the consumption tax on solvent-based coatings, making two-component waterborne wood coatings the first choice for high-grade waterborne wood coatings.

Two-component waterborne polyurethane coatings have been widely studied and applied for their excellent film properties. They are composed of an aqueous polymer polyol and an aqueous polyisocyanate curing agent, which are packaged separately and mixed in proportion when used. Among them, the aqueous polymer polyol includes an aqueous polyacrylate polyol, an aqueous polyurethane polyol, an aqueous polyester polyol and a polyether polyol, and a mixed polyol. Among them, water-based polyacrylate polyol has excellent color retention, gloss retention and weather resistance, low cost, and easy to adjust molecular weight, glass transition temperature (Tg) and hydroxyl content, and is currently water-based in two-component waterborne polyurethane coatings. The first choice for polymer polyols. Two types of polyacrylate polyols, emulsion type and dispersion type, can be obtained by different polymerization processes. The aqueous polyacrylate dispersion has a high hydroxyl content, and the formulated coating film has excellent water resistance and chemical resistance. A large amount of organic solvent is used in the production process, and the solid content of the product is low, generally 30% to 40%. And the paint film has a slow dry speed and high cost. In contrast, emulsion polyacrylate polyols (also known as hydroxy polyacrylate emulsions) have a simple production process with a solid content of up to 50%, low cost, and fast dry speed. Therefore, the two-component polyurethane coating formulated with the hydroxy polyacrylate emulsion occupies a large market space for the aqueous two-component coating.

The paint film prepared by the existing hydroxy polyacrylate emulsion and the aqueous polyisocyanate curing agent still has problems of poor appearance, poor chemical resistance, and low hardness. The main performance of the paint film is poor in transparency and low gloss of the paint film. The main reason is that the hydroxypolyacrylate emulsion has poor emulsifying and dispersing ability to the curing agent and poor compatibility with the curing agent. To ensure paint When the Tg of the polyacrylate designed to have high hardness is high, the compatibility with the curing agent is poor, resulting in poor appearance of the paint film. The higher the crosslink density of the paint film, the better the chemical resistance, and the high hydroxyl content polyacrylate can obtain a high crosslink density paint film. However, the conventional high hydroxyl content polyacrylate emulsion has poor polymerization stability and is unstable in industrial production. In addition, excessive use of an emulsifier or an emulsifier in an emulsion polymerization may reduce the gloss and chemical resistance of the paint film. At present, improving the hardness and chemical resistance of aqueous two-component polyurethane paint film by increasing the glass transition temperature and hydroxyl content of the hydroxy polyacrylate emulsion, and also requiring more organic small molecule film formation in the paint process. Agents and curing agents (the curing agent often contains a certain amount of co-solvent), increasing the volatile organic compound (VOC) content in the coating will also lead to an increase in coating costs. Therefore, the conventional method is difficult to improve the poor appearance of the hydroxy polyacrylate emulsion type two-component paint film, poor chemical resistance, and low hardness.

Chinese invention patent application CN103059210 modified hydroxy polyacrylate emulsion by adding 2%-5% fluorine-containing acrylic acid monomer, which slightly improved the water resistance and chemical resistance of the two-component paint film due to fluorine-containing acrylic acid The hydrophobic oleophobic property of the ester monomer makes the conversion rate of the polymerization reaction not high, and it is easy to cause a large amount of residual fluorine-containing monomer, and also causes problems such as poor interlayer adhesion of the paint film, and the fluorine-containing acrylate monomer. The high price causes the polymer emulsion cost to rise sharply.

Summary of the invention

The object of the present invention is to overcome the problems existing in the prior art and to provide an easy adjustment of the hydroxyl content of the hydroxy polyacrylate emulsion, so that a plurality of hydroxy resins of different structures, different molecular weights and different glass transition temperatures form a multiple crossover with the curing agent. Linked hydroxy polyacrylate emulsion and preparation method thereof.

Another object of the present invention is to provide the use of the hydroxy polyacrylate emulsion in an aqueous two-component polyurethane coating, so that the coating hardness of the two-component polyurethane coating reaches H, and the gloss (60 ⁰ ) reaches 83%, which is excellent. Water/ethanol resistance and good dry heat resistance.

The invention aims at the deficiencies of the prior art, and adopts a process of adding a high hydroxyl content oligomer in the process of hydroxypolyacrylate emulsion polymerization to prepare a hydroxy polyacrylate emulsion having a suitable hydroxyl content, which not only realizes a hydroxy polyacrylate emulsion. The hydroxyl group content is easily adjusted, and a plurality of hydroxy resins having different structures, different molecular weights and different Tg and the curing agent form a multiple crosslinked structure. Compared with the conventional emulsion having the same hydroxyl content without adding a hydroxyl oligomer, the appearance of the paint film is greatly improved, the hardness of the paint film is improved, and the problem of poor chemical resistance is solved. At the same time, under the premise of ensuring emulsion polymerization stability and high monomer conversion rate, the hydroxyl group content of the hydroxy polyacrylate emulsion of the invention can be adjusted wider, and the high hydroxyl content hydroxy polyacrylate emulsion is easy to realize large-scale industrialization. produce. In addition, the present invention employs a special acrylic monomer such as isobornyl (meth)acrylate to improve the compatibility of the hydroxypolyacrylate emulsion with the curing agent, thereby improving the appearance of the paint film.

The technical solution adopted to achieve the object of the present invention:

The preparation method of the hydroxy polyacrylate emulsion comprises the following steps:

Weigh 30 to 45 parts of acrylate monomer and/or methacrylate monomer, 5 to 15 parts of hydroxy acrylate monomer, 1.0 to 3.0 parts of acrylate monomer, and acrylate functional monomer 0.5 in parts by mass. ～3.0 parts, 0.5 to 3 parts of hydroxy oligomer, uniformly mixed to prepare a monomer mixture, and 10-15% of the monomer mixture is emulsified with 1-2 parts of emulsifier to prepare a seed pre-emulsion;

Add 1 to 2 parts of emulsifier, 0.05-0.2 parts of sodium bicarbonate and 20 to 30 parts of deionized water to the reaction kettle, stir and raise the temperature of the reaction system. When the temperature reaches 78-83 ° C, add 10-15. % initiator, after 5-15 minutes of stabilization, add the seed pre-emulsion in 15-30 minutes, stabilize for 15-30 minutes, dissolve the remaining monomer mixture and dissolve the remaining initiator with 10-20 parts of water. After 3-4 hours, the temperature is increased to 80-85 ° C for 1-2 hours, cooled to 40-60 ° C, diluted with 3 to 10 parts of water 0.3-0.6 parts neutralizer, and kept for 15-30 minutes. Cooling out of the hydroxy polyacrylate emulsion;

The hydroxy acrylate monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate;

The hydroxy acrylate monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, methacrylic acid hydroxyethyl ester and hydroxypropyl methacrylate.

The acrylic monomer is one or more of acrylic acid and methacrylic acid.

The acrylate functional monomer is one or more of acrylamide, isobornyl methacrylate, glycidyl methacrylate, and acetoacetoxyethyl methacrylate.

The hydroxy oligomer is BASF's aldehyde resin A81, Changsha Zhengtai Industrial Co., Ltd. aldehyde ketone resin KR-80F, KR-120, KR120B, KR-120W, Wenkel's aldehyde-ketone resin UK-100, One or more of YHKR-1210 and YHKR-1218 of UK-300, UK-500, Baling Petrochemical aldehyde and ketone resin.

The emulsifier is an isomeric alcohol polyoxyethylene ether (EH-9), Adeco's ADEKA REASOAP series of nonionic (ER-30) and anionic (SR-10) emulsifiers, 2-acrylamido-2 - one or more of sodium methylpropane sulfonate (COPS-2), fatty alcohol polyoxyethylene ether ammonium sulfate (KL-525), sodium dodecyl sulfate (SDS).

The initiator is one or more of potassium persulfate and ammonium persulfate.

A hydroxy polyacrylate emulsion prepared by the above preparation method. The obtained hydroxy polyacrylate emulsion had a particle size of <300 nm, a solid content of 45-52%, a hydroxyl value of 40-150 mgKOH/g, and a Tg of 10-80 °C.

The hydroxy polyacrylate emulsion of the invention is mainly used for preparing an aqueous two-component polyurethane coating.

Adding the hydroxy polyacrylate emulsion to the stirred tank, adding 1-10 parts of film-forming auxiliary, 0.05-1.5 parts of antifoaming agent, 0.05-0.2 part thickener, 0.05-0.3 part by weight, in parts by mass And 0.05-0.1 parts neutralizer, dispersed for 10-30 minutes, filtered Discharge, a coating prepared from a hydroxy polyacrylate emulsion;

The film forming aid is one or more of propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, and dipropylene glycol butyl ether.

The antifoaming agent is TEGO's polyether siloxane copolymer defoamer TEGO-800, TEGO-805, TEGO-815, TEGO-825 and BYK modified polysiloxane copolymer solution BYK-019 One or more of BYK-020.

The thickener is DOW's nonionic polyurethane associative thickener RM-8W, hydrophobically modified alkali swellable associative thickener TT-935, alkali swollen non-associative thickener ASE-60 and One or more of TEGO's nonionic associative thickeners TEGO ViscoPlus 3000, TEGO Visco Plus 3030, TEGO Visco Plus 3060.

The wetting agent is one or more of TEGO's polyether siloxane copolymer TEGO-245, nonionic organic surfactant TEGO-500 and BYK's polyether modified polysiloxane solution BYK-346. Kind.

The neutralizing agent is one or more of triethylamine and dimethylethanolamine.

The polyisocyanate curing agent includes one or more of a sulfonate, a carboxylate, and an alkoxy hydrophilically modified hexamethylene diisocyanate (HDI).

The obtained aqueous two-component polyurethane coating film has the advantages of high gloss, high transparency, excellent water and chemical resistance, high crosslink density, high hardness, scratch resistance and abrasion resistance. Can be applied to high-grade wood coatings, automotive coatings, metal anti-corrosion coatings and other industrial protective coatings.

Compared with the prior art, the present invention has the following advantages:

The chemical resistance of the aqueous two-component polyurethane coating film is determined by the cross-linking density of the coating film, which is controlled by the OH group content of the hydroxy polyacrylate emulsion and the molar ratio of NCO to OH; the appearance and decorative properties of the coating film are determined by the inter-component phase. The compatibility determines that the compatibility is related to the structure, particle structure and morphology of the aqueous hydroxy resin, the emulsifying ability of the curing agent, and the emulsifier content. The hydroxy polyacrylate emulsion of the present invention has a polyacrylate polyol as a main hydroxyl component and a hydroxy oligomer as an auxiliary hydroxyl component. First, a proper amount of hydroxy oligomer is dissolved by a monomer mixture, pre-emulsified with an appropriate amount of an emulsifier, and some or all of the pre-emulsion is used to prepare seeds, and a hydroxy polyacrylate can be obtained by a pre-emulsified seed emulsion polymerization process. Emulsion. The invention avoids the problem that the polymerization stability caused by the excessive addition of the hydroxy acrylate monomer is drastically reduced. Therefore, by adjusting the kind and the amount of the hydroxy oligomer, the hydroxyl value of the emulsion can be greatly increased and the hydroxyl structure can be adjusted, thereby improving the double The mechanical and chemical properties of the component coating. At the same time, the introduced hydroxy oligomer itself has the characteristics of high gloss and high transparency, and can further improve the appearance and decorative properties of the coating film. The coating film of the aqueous two-component polyurethane coating prepared by the hydroxy polyacrylate emulsion of the invention and the aqueous polyisocyanate curing agent has high hardness, high gloss and excellent chemical resistance, and solves the problem of the traditional hydroxy polyacrylate emulsion due to the hydroxyl value. Overcoming the problem of poor mechanical and chemical properties of the paint film, overcoming the problem The paint film prepared with the aqueous polyisocyanate curing agent has low gloss and poor transparency.

Specific embodiment

The present invention will be further described below in conjunction with the specific embodiments, but the embodiments of the present invention are not limited thereto, and the process parameters not specifically noted may be referred to conventional techniques.

The detection methods of the following embodiments are as follows:

The basic performance test includes: the hydroxy polyacrylate emulsion is tested according to GB/T11175-2002 "Test Method for Synthetic Resin Emulsion" to test the appearance, pH, solid content and viscosity of the emulsion. The performance of the paint film is tested according to GB/T23999-2009 "Water-based wood coating for interior decoration and decoration", and the gloss, hardness, water resistance, dry heat resistance and alcohol resistance are tested. The average particle size of the emulsion was measured using a nanoparticle size analyzer (ZS Nano S).

Example 1

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 65 mg KOH / g) is as shown in Table 1a:

Table 1a

Preparation process: Mixing 1-9 to prepare a monomer mixture, pre-emulsification of 10% monomer mixture with 0.05 parts of emulsifier (0.025 parts of KL-525 and 0.025 parts of COPS-2) and 2.75 parts of water as seed pre-emulsified liquid. Add the remaining emulsifier, sodium bicarbonate, 0.1 part initiator (potassium persulfate), 25 parts deionized water to the reaction kettle, raise the temperature to 78 ° C, stir for 15 minutes, and spray the seed pre-emulsion at a constant rate within 20 minutes. After the emulsion was stabilized for half an hour, a seed emulsion was obtained. Guarantee The temperature of the reaction system was 80 °C. The remaining mixed monomer was mixed with the remaining monomers, and then added dropwise to the seed emulsion while dropwise adding an aqueous solution of 0.15 parts of an initiator (potassium persulfate) with 15 parts of water, and dropping was carried out at about 3.5 hours. After the addition was completed, the temperature was raised to 85 ° C and kept for 1.5 h. The temperature was lowered to 55 ° C, 5.5 parts of water and the neutralizing agent triethylamine were mixed, neutralized, and incubated for 0.25 h, and the temperature was discharged to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion had an average particle diameter of 128 nm, viscosity: 535 cps, pH = 7.0, and solid content: 48.3%.

(3) Preparation of high performance waterborne two-component polyurethane coating: The formulation is shown in Table 1b:

Table 1b

Wherein the molar ratio of the NCO group in the curing agent to the OH group in the hydroxy polyacrylate emulsion is 1.8:1.

The preparation method is as follows: the emulsion is added to the stirred tank at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 20 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxypolyacrylate emulsion, and stirred for 6 minutes to obtain an aqueous two-component polyurethane coating.

(4) Coating performance: The paint film obtained by the aqueous two-component polyurethane coating was cured and dried at room temperature for 7 days, and its properties are as follows:

Table 1c Comprehensive performance of high performance waterborne two-component polyurethane coatings

In this embodiment, a hydroxy oligomer A81 is added to a hydroxy polyacrylate emulsion having a lower hydroxyl content, and the emulsified seed emulsion is prepared by dissolving the monomer and pre-emulsification, and preparing a hydroxy polyacrylate emulsion on the basis of the seed emulsion. The method ensures that the hydroxy oligomer is stably dispersed in the hydroxy polyacrylate emulsion, mainly in the latex particles, and the acrylate monomer is polymerized in the hydroxy oligomer to form an interpenetrating polymer of the polyacrylate and the hydroxy oligomer. The network, on the one hand, ensures thorough mixing between the hydroxy oligomer and the acrylic polymer. On the other hand, a small amount of acrylic polymer may be grafted onto the hydroxy oligomer, and the graft polymer provides a polymer-compatible bridge. The addition of the hydroxy oligomer increases the hydroxyl content of the hydroxy polyacrylate emulsion, ensures the polymerization stability of the hydroxy polyacrylate emulsion, and makes the two-component coating film hardness H, gloss (60 ⁰ ) 83%, excellent The water/ethanol resistance and the good dry heat resistance, the hydroxy polyacrylate emulsion prepared by the method overcomes the shortcomings of the conventional hydroxy polyacrylate emulsion to prepare the two-component polyurethane coating.

Example 2

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 65 mg KOH / g) is shown in Table 2a:

Table 2a

Preparation method: mixing 1-8 to prepare a monomer mixture, taking 15% monomer mixture dissolved in 0.1 part emulsifier (0.05 parts of SR-10 and ER-30 each) and 3 parts of water to pre-emulsifie it as seed pre-emulsified liquid. Add the remaining emulsifier, sodium bicarbonate, 0.1 part initiator (ammonium persulfate), 30 parts deionized water to the reaction kettle, raise the temperature to 80 ° C, stir for 30 minutes, The seed pre-emulsion was continuously sprayed in 30 minutes, and the emulsion was stabilized for half an hour to obtain a seed emulsion. The temperature of the reaction system was maintained at 80 °C. The remaining monomer mixture was added dropwise to the seed emulsion while an aqueous solution of 0.2 part of an initiator (ammonium persulfate) dissolved in 20 parts of water was added dropwise, and the mixture was dropped over 4 hours. After the addition was completed, the temperature was raised to 82 ° C and kept for 2 h. The temperature was lowered to 45 ° C, 10 parts of water and N,N-dimethylethanolamine were mixed, neutralized, and incubated for 0.25 h, and the temperature was lowered to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion had an average particle diameter of 135 nm, viscosity: 573 cps, pH = 7.0, and solid content: 48.5%.

(3) Preparation of high performance waterborne two-component polyurethane coating: The formulation is shown in Table 2b:

Table 2b

Wherein the molar ratio of the NCO group in the curing agent to the OH group in the hydroxy polyacrylate emulsion is 1.5:1.

The preparation method is as follows: the emulsion is added to the stirred tank at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 10 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxy polyacrylate emulsion, and stirred for 5 minutes to obtain an aqueous two-component polyurethane coating.

(4) Two-component coating performance: The paint film obtained by the aqueous two-component polyurethane coating was cured and dried at room temperature for 7 days, and its properties are as follows:

Table 2c Comprehensive performance of high performance waterborne two-component polyurethane coatings

Example 3

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 70 mg KOH / g) is shown in Table 3a:

Table 3a

Preparation Process: A monomer mixture was prepared by mixing 1-8, and 12% of the monomer mixture was pre-emulsified as a seed pre-emulsion with 0.1 part of an emulsifier (0.05 parts each of two emulsifiers) and 3 parts of water. The remaining emulsifier, sodium hydrogencarbonate, 0.1 part initiator (KPS), 20 parts of deionized water were added to the reaction kettle, the temperature was raised to 82 ° C, stirred for 15 minutes, and the seed pre-emulsion was continuously sprayed in 15 minutes. The emulsion was stabilized for half an hour to give a seed emulsion. The temperature of the reaction system was maintained at 82 °C. The remaining monomer mixture was mixed with the remaining monomers, and then added dropwise to the seed emulsion, while an aqueous solution of 0.2 part of initiator (KPS) dissolved in 10 parts of water was added dropwise, and the mixture was dropped over 3 hours. After the addition was completed, the temperature was raised to 85 ° C and kept for 1 h. The temperature was lowered to 60 ° C, 5.9 parts of water and triethylamine were mixed, neutralized, and kept for 30 minutes, and the temperature was discharged to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion had an average particle diameter of 123 nm, viscosity: 617 cps, pH = 7.0, and solid content: 48.0%.

(3) Preparation of high performance waterborne two-component polyurethane coating: The formulation is shown in Table 3b:

Table 3b

Wherein the molar ratio of the NCO group in the curing agent to the OH group in the hydroxy polyacrylate emulsion is 1.2:1.

The preparation method is as follows: the emulsion is added to the stirred tank at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 10 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxy polyacrylate emulsion, and stirred for 8 minutes to obtain an aqueous two-component polyurethane coating.

(4) Paint film performance of water-based two-component polyurethane paint: The paint film was cured and dried at room temperature for 7 days, and its properties are as follows:

Table 3c Comprehensive performance of high performance waterborne two-component polyurethane coatings

Example 4

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 79 mg KOH / g) is shown in Table 4a:

Table 4a

Preparation Process: A monomer mixture was prepared by uniformly mixing 1-8, and 14 parts of the monomer mixture was pre-emulsified as a seed pre-emulsion with 0.1 part of an emulsifier (0.05 parts each of two emulsifiers) and 3.35 parts of water. The remaining emulsifier, sodium bicarbonate, 0.1 part initiator, 25 parts deionized water was added to the reaction kettle, the temperature was raised to 75 ° C, and stirred for 15 minutes. The seed pre-emulsion was continuously dropped in 20 minutes, and the emulsion was stabilized for half. In hours, a seed emulsion is obtained. The temperature of the reaction system was maintained at 80 °C. The remaining monomer mixture was added dropwise to the seed emulsion while dropwise adding an aqueous solution of 0.2 part of the initiator with 15 parts of water, and dropping was carried out at about 3.5 hours. After the addition was completed, the temperature was raised to 85 ° C and kept for 1.5 h. The temperature was lowered to 55 ° C, 6 parts of water and N,N-dimethylethanolamine were mixed, neutralized, and incubated for 0.25 h, and the mixture was cooled to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion had an average particle diameter of 119 nm, viscosity: 820 cps, pH = 7.0, and solid content: 47.7%.

(3) Preparation of high performance waterborne two-component polyurethane coating: Formulation is shown in Table 4b:

Table 4b

The preparation method is as follows: the emulsion is added to the stirred tank at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 25 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxypolyacrylate emulsion, and stirred for 7 minutes to obtain an aqueous two-component polyurethane coating.

(4) Coating performance of water-based two-component polyurethane coating: The paint film obtained by the aqueous two-component polyurethane coating is cured and dried at room temperature for 7 days, and its properties are as follows:

Table 4c Comprehensive performance of high performance waterborne two-component polyurethane coatings

Example 5

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 95 mg KOH / g) is shown in Table 5a:

Table 5a

Preparation Process: A monomer mixture was prepared by uniformly mixing 1-7, and 13 parts of the monomer mixture was pre-emulsified as a seed pre-emulsion with 0.1 part of an emulsifier (0.05 parts each of two emulsifiers) and 4 parts of water. The remaining emulsifier, sodium bicarbonate, 0.1 part initiator, 25 parts deionized water was added to the reaction kettle, the temperature was raised to 75 ° C, and stirred for 15 minutes. The seed pre-emulsion was continuously dropped in 20 minutes, and the emulsion was stabilized for half. In hours, a seed emulsion is obtained. The temperature of the reaction system was maintained at 80 °C. The remaining monomer mixture was added dropwise to the seed emulsion while dropwise adding an aqueous solution of 0.2 part of the initiator with 15 parts of water, and dropping was carried out at about 3.5 hours. After the addition was completed, the temperature was raised to 85 ° C and kept for 1.5 h. The temperature was lowered to 55 ° C, 5.9 parts of water and triethylamine were mixed, neutralized, and incubated for 0.25 h, and the temperature was discharged to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion had an average particle diameter of 132 nm, viscosity: 673 cps, pH = 7.0, and solid content: 48.2%.

(3) Preparation of high performance waterborne two-component polyurethane coating: The formulation is shown in Table 5b:

Table 5b

The preparation method is as follows: the emulsion is added to the stirring kettle at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 30 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxypolyacrylate emulsion, and stirred for 6 minutes to obtain an aqueous two-component polyurethane coating.

Table 5c Comprehensive performance of high performance waterborne two-component polyurethane coatings

Example 6

(1) Preparation of hydroxy polyacrylate emulsion: The formulation of hydroxy polyacrylate emulsion (hydroxyl value = 110 mg KOH / g) is shown in Table 6a:

Table 6a

Preparation Process: A monomer mixture was prepared by uniformly mixing 1-7, and a 10% monomer mixture was pre-emulsified as a seed pre-emulsion with 0.1 part of an emulsifier (0.05 parts each of two emulsifiers) and 4.5 parts of water. The remaining emulsifier, sodium bicarbonate, 0.1 part initiator, 25 parts deionized water was added to the reaction kettle, the temperature was raised to 75 ° C, and stirred for 15 minutes. The seed pre-emulsion was continuously dropped in 20 minutes, and the emulsion was stabilized for half. In hours, a seed emulsion is obtained. The temperature of the reaction system was maintained at 80 °C. The remaining monomer mixture mixture was added dropwise to the seed emulsion while dropwise adding an aqueous solution of 0.2 part of the initiator with 15 parts of water, and dropping was carried out for about 3.5 hours. After the addition was completed, the temperature was raised to 85 ° C and kept for 1.5 h. The temperature was lowered to 55 ° C, and 5.55 parts of water and N,N-dimethylethanolamine were mixed, neutralized, and incubated for 0.25 h, and the mixture was cooled to obtain a milky white semipermeable hydroxy polyacrylate emulsion.

(2) Properties of hydroxy polyacrylate emulsion: The prepared emulsion has an average particle diameter of 125 nm, viscosity: 725 cps, pH = 7.0, solid content: 47.6%.

(3) Preparation of high performance waterborne two-component polyurethane coating: The formulation is shown in Table 6b:

Table 6b

Wherein the molar ratio of the NCO group in the curing agent to the OH group in the hydroxy polyacrylate emulsion is 1.0:1.

The preparation method is as follows: the emulsion is added to the stirred tank at a rotation speed of 700 rpm, 10 parts of water is premixed with the film forming aid, and then added to the emulsion, and the raw materials of No. 5-9 are sequentially added, dispersed for 20 minutes, and the material is filtered. . During the construction, an aqueous polyisocyanate curing agent was added to the coating prepared by the above hydroxy polyacrylate emulsion, and stirred for 5 minutes to obtain an aqueous two-component polyurethane coating.

Table 6c Comprehensive performance of high performance waterborne two-component polyurethane coatings

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and combinations thereof may be made without departing from the spirit and scope of the invention. Simplifications should all be equivalent replacements and are included in the scope of the present invention.

Claims

A method for preparing a hydroxy polyacrylate, which comprises the following steps,

1) Weigh 30 to 45 parts of acrylate monomer and/or methacrylate monomer, 5 to 15 parts of hydroxy acrylate monomer, and 1.0 to 3.0 parts of acrylic monomer in parts by mass, acrylate function sheet 0.5 to 3.0 parts of the body, 0.5 to 3 parts of the hydroxy oligomer, uniformly mixed to prepare a monomer mixture, and 10-15% of the monomer mixture is emulsified with 1-2 parts of an emulsifier to prepare a seed pre-emulsion;

2) In parts by mass, add 1 to 2 parts of emulsifier, 0.05-0.2 parts of sodium hydrogencarbonate and 20 to 30 parts of deionized water to the reaction kettle, stir and raise the temperature of the reaction system, when the temperature reaches 78 After adding -10-15% initiator at -83 °C, after 5-15 minutes of stabilization, add the seed pre-emulsion after 15-30 minutes, stabilize for 15-30 minutes, and mix the remaining monomer mixture with 10-20 The remaining initiator of the water is dissolved in 3-4 hours, heated to 80-85 ° C for 1-2 hours, cooled to 40-60 ° C, diluted with 0.3 to 0.6 parts of neutralizer with 3 to 10 parts of water And, after 15-30 minutes of heat preservation, the hydroxy polyacrylate emulsion is discharged by cooling;

The acrylate monomer and/or methacrylate monomer is one or more of methyl methacrylate, methyl acrylate, ethyl acrylate, butyl methacrylate, butyl acrylate and styrene;

The hydroxy acrylate monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate;

The acrylic monomer is acrylic acid and/or methacrylic acid;

The acrylate functional monomer is one or more of acrylamide, isobornyl methacrylate, glycidyl methacrylate, acetoacetoxyethyl methacrylate;

The hydroxy oligomer is aldehyde resin A81, aldehyde ketone resin KR-80F, KR-120, KR120B, KR-120W, aldehyde ketone resin UK-100, UK-300, UK-500, aldehyde and ketone resin YHKR-1210 And one or more of YHKR-1218;

The emulsifier is an isomeric alcohol polyoxyethylene ether, a polymerizable emulsifier ADEKA REASOAP series nonionic ER-30 and an anionic SR-10 emulsifier, 2-acrylamido-2-methylpropane sulfonate, a fatty alcohol One or more of polyoxyethylene ether ammonium sulfate and sodium lauryl sulfate;

The initiator is one or more of potassium persulfate and ammonium persulfate.
The method for producing a hydroxy polyacrylate emulsion according to claim 1, wherein the neutralizing agent is one or more selected from the group consisting of triethylamine, aqueous ammonia, and dimethylethanolamine.
The method for preparing a hydroxy polyacrylate emulsion according to claim 1, wherein the hydroxyl group is polymerized The acrylate emulsion has a hydroxyl value of 40 to 150 mgKOH/g (based on solid resin).
The method for producing a hydroxy polyacrylate emulsion according to claim 1, wherein the hydroxy polyacrylate emulsion has a glass transition temperature of from 10 to 80 °C.
A hydroxy polyacrylate emulsion characterized in that it is produced by the production method according to any one of claims 1 to 4.
Use of the hydroxy polyacrylate emulsion of claim 5 in an aqueous two-component polyurethane coating.
The use of a hydroxy polyacrylate emulsion according to 6 in an aqueous two-component polyurethane coating is characterized by comprising the steps of:

1) Adding a hydroxy polyacrylate emulsion to a stirred tank, adding 1-10 parts of a film forming aid, 0.05-1.5 parts of an antifoaming agent, 0.05-0.2 parts of a thickening agent, 0.05-0.3 parts by mass a wetting agent and 0.05-0.1 parts of a neutralizing agent, dispersed for 10-30 minutes, filtered and discharged, a coating prepared by a hydroxy polyacrylate emulsion;

2) During the application, the aqueous polyisocyanate curing agent is added to the coating prepared by the hydroxy polyacrylate emulsion according to a NCO/OH molar ratio of 1.0-1.8, and stirred for 5-8 minutes to obtain an aqueous two-component polyurethane coating.
The use of the hydroxy polyacrylate emulsion according to 7 in an aqueous two-component polyurethane coating, characterized in that the film-forming auxiliary agent is one of propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether and dipropylene glycol butyl ether. Species or more;

The antifoaming agent is a polyether siloxane copolymer defoamer TEGO-800, TEGO-805, TEGO-815, TEGO-825, modified polysiloxane copolymer solution BYK-019 and BYK-020 Species or more;

The thickener is a nonionic polyurethane associative thickener RM-8W, a hydrophobically modified alkali swellable associative thickener TT-935, an alkali swollen non-associative thickener ASE-60, a nonionic association One or more of the combined thickeners TEGO ViscoPlus 3000, TEGO ViscoPlus 3030 and TEGO ViscoPlus 3060;

The wetting agent is one or more of polyether siloxane copolymer TEGO-245, nonionic organic surfactant TEGO-500 and polyether modified polysiloxane solution BYK-346;

The neutralizing agent is one or more of triethylamine, ammonia water and dimethylethanolamine;

The polyisocyanate curing agent includes one or more of a sulfonate, a carboxylate, and an alkoxy hydrophilically modified hexamethylene diisocyanate.