CN118909209A - Preparation method of organosilicon modified hydroxy acrylic ester and prepared dispersoid - Google Patents

Abstract

The invention provides an organosilicon modified hydroxy acrylic ester dispersoid and a preparation method thereof, comprising the following steps: introducing acrylic ester double bond modification into the polyether modified organosilicon monomer (1) to prepare an organosilicon intermediate a; introducing acrylic ester double bond modification into the organosilicon monomer (2) to prepare an organosilicon intermediate b; taking an organosilicon intermediate a, (methyl) acrylic ester containing hydroxyl and polyethylene glycol (methyl) acrylic monomer as raw materials to obtain a monomer mixture; preparing organosilicon modified hydroxy acrylic resin by taking an organosilicon intermediate b and a small amount of solvent as a base material under the action of a thermal initiator; and adding water into the obtained organosilicon modified hydroxy acrylic resin at a certain temperature for dispersion, and filtering to obtain the organosilicon modified hydroxy acrylic ester dispersoid. The invention solves the contradiction between high contact angle/high stain resistance of organosilicon modified hydroxy acrylic ester dispersion and high permeability of paint film, and has obvious optimization and improvement on contact angle, stain resistance, permeability and other properties.

Description

A method for preparing silicone-modified hydroxy acrylate and the prepared dispersion

Technical Field

The invention relates to the technical field of industrial water-based coatings, in particular to a method for preparing a resin dispersion, and in particular to a method for preparing a silicone-modified hydroxy acrylate dispersion.

Background Art

Nowadays, the surfaces of many objects need to be protected, decorated or given some special functions by coatings. Most existing coatings are solvent-based coatings, and the solvents will evaporate into the atmosphere to pollute the environment and harm human health. In addition, organic solvents themselves will bring potential safety hazards. Therefore, water-based coatings are the development trend of international coatings.

Among water-based coatings, two-component water-based polyurethane (PU) coatings have been widely studied and applied in the industry due to their excellent coating film properties. Two-component water-based polyurethane coatings are made of water-based polymer polyols and water-based polyisocyanate curing agents. The two raw materials are packaged separately and mixed in proportion when used to obtain two-component water-based polyurethane coatings.

Regarding waterborne polymer polyols, one of the above raw materials, waterborne polyacrylate polyols are currently an important choice of waterborne polymer polyols in two-component waterborne polyurethane coatings because of their low price, excellent color retention, gloss retention, weather resistance, and easy adjustment of molecular weight, glass transition temperature and hydroxyl content. Dispersion-type polyacrylate polyols (also known as "hydroxy polyacrylate dispersions", referred to as "hydroxypropylene dispersions") are an important category because of their high hydroxyl content. The paint film obtained by mixing with waterborne polyisocyanate curing agents has high transparency and good leveling properties, and has excellent water resistance and chemical resistance (but its curing speed is not as fast as that of emulsion-type polyacrylate polyols).

In order to improve the performance of hydroxy acrylic dispersions, the industry will modify hydroxy polyacrylate dispersions. The modification methods include polyester modification, silicone modification, epoxy modification and alkyd modification. When silicone modification is used, the Si-O bond energy in the silicone monomer or resin is high, the bond angle is large, the Si-O-Si main chain is soft, the siloxane molecule has a helical structure, the methyl group is arranged outward and rotates around the Si-O chain, the molecular volume is large, and the cohesive energy density is low. Because silicone monomers containing double bonds (vinyl groups) are cheap and have a wide range of applications, they are one of the most commonly used modified silicones.

Silicone polymers all have a commonality, namely, low surface energy, high water contact angle and stain resistance. Therefore, silicone-modified hydroxy acrylate dispersions have excellent wear resistance, weather resistance and chemical resistance. They can be used in water-based coatings and inks to improve the anti-pollution and durability of the coatings. They can also be used in building sealing materials, adhesives and coating materials to improve the weather resistance, adhesion and anti-aging properties of the products. The industry is very concerned about the research and development of silicone-modified hydroxy acrylate dispersions, for example:

CN 114316173 B discloses an organosilicon-modified hydroxy polyacrylate dispersion and its preparation method and application. The dispersion prepared by the dispersion has high solid content, low small molecule alcohol content, strong storage stability, and especially excellent high temperature storage performance; the paint film prepared by the dispersion has fast drying speed and high hardness.

CN 116554751A discloses a method for preparing a water-based organosilicon acrylate dispersion and a stain-resistant coating. During the film-forming process of a self-made high-content organosilicon-modified acrylate resin, low-surface-energy organosilicon spontaneously accumulates on the surface, which enables the coating to have excellent stain-resistant properties.

CN 109762095 A discloses an organosilicon-modified hydroxy acrylate emulsion and a preparation method thereof, which solves the problems of complicated existing process and large emulsion particle size, and prepares an organosilicon-modified acrylic emulsion with high hydroxyl value and high solid content.

Although the industry has developed silicone-modified hydroxy acrylate dispersions, the structure of silicone-modified hydroxy acrylate dispersions contains both silicone molecular segments and highly polar resin segments. The solubility parameters of the two are quite different, which easily leads to compatibility problems, and phase separation will cause obvious problems with the permeability of the paint film. In addition, the current synthetic water-based acrylic dispersions are mainly achieved by neutralizing the carboxyl group (acrylic acid) to form salts to achieve the hydrophilicity of the molecular chain to obtain the dispersion. The polarity difference between the resin molecular chain and the silicone segment after salt formation will further increase, and the phase separation will be more serious. There are obvious problems with the permeability of the paint film. Therefore, the current silicone-modified acrylic resin dispersions can generally only be used for matte coatings.

In this regard, CN 103059313 B discloses a method for preparing an organosilicon-modified acrylic resin, using an organosilicon monomer containing a small vinyl molecule and an acrylate to copolymerize to prepare an oily organosilicon-modified acrylic resin, and preparing a high-gloss decorative paint film from the resin. However, the organosilicon-modified acrylic resin synthesized by this technology is introduced by using a vinyl siloxane to introduce an organosilicon component. Although this component has a significant improvement on the resin in terms of gloss and weather resistance, it does not have the characteristics of stain resistance/high water contact angle, and the resin is an oily resin, which does not meet the current environmental protection requirements for water-based coatings.

Therefore, how to make the silicone-modified hydroxy acrylate dispersion have high contact angle/high stain resistance, high paint film permeability (compatibility), weather resistance, water resistance and other properties at the same time, so as to broaden the application of the silicone-modified hydroxy acrylate dispersion and increase the application value of the product, is the goal of the present invention to improve and optimize the silicone-modified hydroxy acrylic dispersion.

Summary of the invention

The present invention aims to overcome the problems of compatibility, phase separation and paint film permeability of the prior art silicone-modified hydroxy acrylate dispersion, and provides a method for preparing the silicone-modified hydroxy acrylate dispersion. The silicone-modified hydroxy acrylate dispersion prepared according to the method of the present invention has good compatibility (with a curing agent or other structural resins), good paint film permeability, and high contact angle/fouling resistance.

According to one aspect of the present invention, there is provided a method for preparing a silicone-modified hydroxy polyacrylate dispersion, comprising the following steps:

Step S1, preparing organosilicon intermediate a and organosilicon intermediate b

The polyether-modified silicone monomer (1) is modified by introducing an acrylate double bond to prepare an silicone intermediate a; the silicone monomer (2) is modified by introducing an acrylate double bond to prepare an silicone intermediate b;

Step S2, preparing silicone-modified hydroxy acrylate resin

A monomer mixture is obtained by using an organosilicon intermediate a, a (meth)acrylate monomer, a hydroxyl-containing (meth)acrylate monomer, and a polyethylene glycol (meth)acrylate monomer as raw materials, and an organosilicon intermediate b and a small amount of solvent are used as base materials to prepare an organosilicon-modified hydroxy acrylate resin under the action of a thermal initiator;

Step S3, preparing a silicone-modified hydroxy acrylate dispersion

At a certain temperature, water is added to the organosilicon-modified hydroxy acrylic resin prepared in step S2 for dispersion, and then filtered to obtain the organosilicon-modified hydroxy acrylic ester dispersion.

Preferably, in step S1, the polyether-modified silicone monomer (1) and silicone monomer (2) involved are silicone monomers containing two hydroxyl groups and no epoxy group.

Preferably, in step S1, the introduction of acrylate double bonds into the organosilicon monomer structure is achieved by esterification reaction of acrylic acid monomer with the terminal hydroxyl groups of polyether-modified organosilicon monomer (1) and organosilicon monomer (2), respectively.

Preferably, in step S2, the solvent in the base material is propylene glycol butyl ether.

Preferably, in step S3, when adding water for dispersion, the temperature of the synthetic resin needs to be lowered to 60-100°C; the water is added in three parts.

Preferably, in parts by weight, the raw materials in the monomer mixture include: 1 to 10 parts of silicone intermediate a, 25 to 40 parts of (meth)acrylate monomers, 25 to 35 parts of hydroxyl-containing (meth)acrylate monomers, 10 to 30 parts of polyethylene glycol (meth)acrylate monomers and 1 to 3 parts of initiator; the base material includes 1 to 5 parts of silicone intermediate b and 5 to 10 parts of solvent.

Preferably, in step S1, the polyether-modified silicone monomer (1) is at least one of Shin-Etsu X-22-4952, Shin-Etsu X-22-4272, Shin-Etsu KF-6123 or Silok 8530H.

Preferably, in step S1, the organosilicon monomer (2) is at least one of Shin-Etsu KF-6000, Shin-Etsu KF-6001, Shin-Etsu KF-6002, Shin-Etsu KF-60004, Silok 8550, Silok 8807, Silok 8812, Silok 8814, Silok 8815, Silok 8865H, Silok 8866F1 or Silok 8832F2.

Preferably, in step S1, the acrylic acid monomer is acrylic acid and/or methacrylic acid.

Preferably, in step S1, the molar ratio of the acrylic acid monomer to the polyether-modified silicone monomer (1) for the esterification reaction is 1:0.5 to 1:2; more preferably, the molar ratio is 1:0.75 to 1:1.5.

Preferably, in step S1, the molar ratio of the acrylic acid monomer to the organosilicon monomer (2) for the esterification reaction is 1:0.5 to 1:2; more preferably, the molar ratio is 1:1 to 1:1.5.

Preferably, in step S2, the (meth)acrylate monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, butyl methacrylate, butyl acrylate, tert-butyl methacrylate, isobornyl methacrylate, isobornyl acrylate or cyclohexyl methacrylate.

Preferably, in step S2, the hydroxyl-containing (meth)acrylate monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate or hydroxypropyl methacrylate.

Preferably, in step S2, the polyethylene glycol (meth)acrylate monomer is selected from at least one of polyethylene glycol 400 (meth)acrylate, polyethylene glycol 600 (meth)acrylate, polyethylene glycol 800 (meth)acrylate, polyethylene glycol 1000 (meth)acrylate, polyethylene glycol 1500 (meth)acrylate, polyethylene glycol 2000 (meth)acrylate or polyethylene glycol 3000 (meth)acrylate.

Preferably, in step S2, the thermal initiator is di-tert-amyl hydroperoxide and/or di-tert-butyl hydroperoxide.

Preferably, in step S2, the reaction temperature of the polymerization reaction is 140°C.

Preferably, in step S3, the temperature of the synthetic resin when adding water is 60-100°C; more preferably, the temperature is 80-90°C.

Preferably, in step S3, the step of adding water is divided into three steps, all of which are adding water while dispersing. More preferably, in the first step, 20% to 25% of the total water is added at one time, and the mixture is stirred and dispersed for 1 hour after the addition is completed; in the second step, 30% to 35% of the total water is added at one time, and the mixture is stirred and dispersed for 0.5 hour after the addition is completed; in the third step, 40% to 50% of the total water is added at one time, and the mixture is stirred and dispersed for 1.5 hours after the addition is completed.

Preferably, the water is deionized water.

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

1. Select appropriate silicone monomers and polyether-modified silicone monomers, combine them, and introduce them into the acrylic resin structure at the same time: the introduction of silicone monomers (low solubility parameters, giving acrylic resins high water contact angles/high stain resistance) into the acrylic resin molecular structure (high solubility parameters) will lead to obvious phase separation, while the introduction of polyether-modified silicone monomers (similar and compatible with silicone monomers, and with solubility parameters closer to the acrylic resin structure, playing a bridging role) can significantly improve this phase separation;

2. The organosilicon-modified hydroxy acrylic acid dispersion synthesized according to the method of the present invention is a non-ionic hydrophilic structure. Compared with the carboxyl neutralized salt hydrophilic structure in the prior art, the solubility parameter of the non-ionic structure of the present invention is significantly lower and closer to the solubility parameter of the organosilicon structure, which further reduces phase separation and improves intermolecular compatibility.

Through the combination of the above two mechanisms 1 and 2, the prepared hydroxy acrylic dispersion was optimized, and finally the contradiction between the high contact angle/high stain resistance of the silicone-modified hydroxy acrylic dispersion and the high permeability of the paint film was solved, thereby achieving significant optimization and improvement in contact angle, stain resistance, permeability, etc.

DETAILED DESCRIPTION

In order to make those skilled in the art more clearly understand the technical solution of the present invention, the following embodiments are listed for illustration, but the present invention is not limited to these specific implementations.

The composition ratios of Examples 1-5 and Comparative Examples 1-3 are listed in Table 1 (parts by weight).

Table 1. Composition ratio of Examples 1-5 and Comparative Examples 1-3

[Preparation method]

[Example 1]

The preparation process of the organosilicon-modified hydroxy acrylate dispersion according to Example 1 of the present invention is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

Shin-Etsu X-22-4952 was subjected to an esterification reaction with acrylic acid (AA) to prepare an organosilicon intermediate a, and the molar ratio of the two was 1:0.75.

Silok 8814 and acrylic acid (AA) were subjected to esterification reaction to prepare organosilicon intermediate b, and the molar ratio of the two materials was 1:1.25.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 2.5 parts of silicone intermediate a, 10 parts of methyl methacrylate, 22.5 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-amyl hydroperoxide were mixed uniformly to obtain a monomer/initiator mixture; 5 parts of silicone intermediate b and 10 parts of solvent were used as base materials and reacted at 140° C. to prepare a silicone-modified hydroxy acrylate resin.

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the silicone-modified hydroxy polyacrylate dispersion. The particle size of the dispersion was 185 nm, the pH was 7.2, the hydroxyl content was 3.9%, and the solid content was 44%.

[Example 2]

The preparation process of the organosilicon-modified hydroxy acrylate dispersion according to Example 2 of the present invention is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

The preparation method is consistent with that of the organosilicon intermediate a and the organosilicon intermediate b in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 5 parts of silicone intermediate a, 10 parts of methyl methacrylate, 20 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-amyl hydroperoxide are mixed uniformly to obtain a monomer/initiator mixture; 5 parts of silicone intermediate b and 10 parts of solvent are used as base materials, and the reaction is carried out at 140° C. to prepare a silicone-modified hydroxy acrylate resin.

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the silicone-modified hydroxy polyacrylate dispersion. The particle size of the dispersion was 140 nm, the pH was 7.35, the hydroxyl content was 3.9%, and the solid content was 43%.

[Example 3]

The preparation process of the organosilicon-modified hydroxy acrylate dispersion according to Example 3 of the present invention is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

The preparation process of the organosilicon intermediate a and the organosilicon intermediate b is the same as that in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 7.5 parts of silicone intermediate a, 10 parts of methyl methacrylate, 17.5 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-amyl hydroperoxide were mixed uniformly to obtain a monomer/initiator mixture; 5 parts of silicone intermediate b and 10 parts of solvent were used as base materials, and the reaction was carried out at 140° C. to prepare a silicone-modified hydroxy acrylate resin;

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the organic silicon modified hydroxy polyacrylate dispersion. The dispersion had a particle size of 125 nm, a pH of 7.65, a hydroxyl content of 3.9%, and a solid content of 42%.

[Example 4]

The preparation process of the organosilicon-modified hydroxy acrylate dispersion according to Example 4 of the present invention is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

The preparation process of the organosilicon intermediate a and the organosilicon intermediate b is the same as that in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 5 parts of organosilicon intermediate a, 10 parts of methyl methacrylate, 22.5 parts of butyl methacrylate, 30 parts of hydroxypropyl acrylate, 10 parts of isobornyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-butyl hydroperoxide were mixed uniformly to obtain a monomer/initiator mixture; 2.5 parts of organosilicon intermediate b and 10 parts of solvent were used as base materials, and the reaction was carried out at 140° C. to prepare an organosilicon-modified hydroxy acrylate resin;

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the organic silicon modified hydroxy polyacrylate dispersion. The dispersion had a particle size of 110 nm, a pH of 7.78, a hydroxyl content of 3.9%, and a solid content of 41%.

[Example 5]

The preparation process of the organosilicon-modified hydroxy acrylate dispersion according to Example 5 of the present invention is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

The preparation process of the organosilicon intermediate a and the organosilicon intermediate b is the same as that in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 5 parts of organosilicon intermediate a, 10 parts of methyl methacrylate, 17.5 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-butyl hydroperoxide were mixed uniformly to obtain a monomer/initiator mixture; 7.5 parts of organosilicon intermediate b and 10 parts of solvent were used as base materials, and the reaction was carried out at 140° C. to prepare an organosilicon-modified hydroxy acrylate resin;

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the organic silicon modified hydroxy polyacrylate dispersion. The dispersion had a particle size of 168 nm, a pH of 7.28, a hydroxyl content of 3.9%, and a solid content of 43%.

[Comparative Example 1]

A silicone-modified hydroxy acrylate dispersion, the preparation components of which do not include silicone monomer a for comparison, is prepared as follows.

Step S1: Preparation of organosilicon intermediate b

The preparation process is the same as that of the organosilicon intermediate b in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 10 parts of methyl methacrylate, 25 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-butyl hydroperoxide are mixed uniformly to obtain a monomer/initiator mixture; 5 parts of silicone intermediate b and 10 parts of solvent are used as base materials, and the reaction is carried out at 140° C. to prepare a silicone-modified hydroxy acrylate resin.

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for another 1.5 hours after the addition.

The material was filtered out, and the filtrate was the organic silicon-modified hydroxy polyacrylate dispersion of Comparative Example 1. The dispersion had a particle size of 210 nm, a pH of 7.2, a hydroxyl content of 3.9%, and a solid content of 44%.

[Comparative Example 2]

A silicone-modified hydroxy acrylate dispersion, the preparation ingredients of which do not include silicone monomer b, is used as a comparison, and the preparation process thereof is as follows.

Step S1: Preparation of organosilicon intermediate a

The preparation process is the same as that of the organosilicon intermediate a in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 5 parts of silicone intermediate a, 10 parts of methyl methacrylate, 25 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, 20 parts of polyethylene glycol 1000 methacrylate, and 1.5 parts of di-tert-butyl hydroperoxide are mixed uniformly to obtain a monomer/initiator mixture; 10 parts of solvent are used as a base material, and the reaction is carried out at 140° C. to prepare a silicone-modified hydroxy acrylate resin.

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 was lowered to 80°C, and water was added while dispersing. In the first step, 30.56 parts of water were added at one time, and stirred and dispersed for 1 hour after the addition; in the second step, 42.78 parts of water were added at one time, and stirred and dispersed for 0.5 hours after the addition; in the third step, 48.89 parts of water were added at one time, and stirred and dispersed for 1.5 hours after the addition.

The material was filtered out, and the filtrate was the organic silicon modified hydroxy polyacrylate dispersion of Comparative Example 2. The dispersion had a particle size of 105 nm, a pH of 7.2, a hydroxyl content of 3.9%, and a solid content of 40%.

[Comparative Example 3]

A silicone-modified hydroxy acrylate dispersion replaces the nonionic hydrophilic structure with a carboxyl salt-forming hydrophilic structure. For comparison, the preparation process is as follows.

Step S1: Preparation of organosilicon intermediate a and organosilicon intermediate b

The preparation process of the organosilicon intermediate a and the organosilicon intermediate b is the same as that in Example 1.

Step S2: Preparation of silicone-modified hydroxy acrylate resin

According to weight parts, 5 parts of silicone intermediate a, 4 parts of acrylic acid, 16 parts of methyl methacrylate, 30 parts of butyl methacrylate, 10 parts of isobornyl acrylate, 30 parts of hydroxypropyl acrylate, and 1.5 parts of di-tert-butyl hydroperoxide are mixed uniformly to obtain a monomer/initiator mixture; 5 parts of silicone intermediate b and 10 parts of solvent are used as base materials, and reacted at 140° C. to prepare a silicone-modified hydroxy acrylate resin.

Step S3: Preparation of silicone-modified hydroxy polyacrylate dispersion

The temperature of the organosilicon-modified hydroxy acrylic resin synthesized in step S2 is lowered to 80°C, and the neutralizer DMEA is added to neutralize it according to 80% neutralization amount. Then add water while dispersing. In the first step, 30.56 parts of water are added at one time, and stirred and dispersed for 1 hour after adding; in the second step, 42.78 parts of water are added at one time, and stirred and dispersed for 0.5 hours after adding; in the third step, 48.89 parts of water are added at one time, and stirred and dispersed for 1.5 hours after adding.

The material was filtered out, and the filtrate was the organic silicon modified hydroxy polyacrylate dispersion of Comparative Example 3. The dispersion had a particle size of 85 nm, a pH of 7.95, a hydroxyl content of 3.9%, and a solid content of 40%.

[Performance test]

The silicone-modified hydroxy acrylate dispersion is compounded with a curing agent (such as Bayer's XP2655, according to OH:NCO=1:1.4), and mixed in a conventional manner, such as mixing in a high-speed disperser, to obtain a water-based two-component PU coating. Then, the resulting mixture coating is applied to a substrate according to a conventional method. In the present invention, the mixture coating is applied by spraying during testing.

The present invention has no particular limitation on the material of the substrate, and the substrate may be, for example, plastic, wood, film, etc. The embodiment of the present invention uses a PC substrate when performing performance testing.

After the coating is cured, a water-based coating is formed, and the water contact angle, stain resistance (whether an oil-based marker leaves marks when wiped), weather resistance and coating permeability of the coating are tested.

[Test method]

Transparency: The transparency of the coating is determined by testing the haze value of the coating according to the standard GB/T 2410-2008. The larger the haze value (percentage), the worse the transparency.

Weather resistance: During the test, the coated substrate is placed under a xenon lamp for artificial aging for 1500 hours, and its color difference value △E is measured according to GB/T 1865-79 standard. The larger the △E value, the more obvious the yellowing and the worse the weather resistance.

Water contact angle: Test the contact angle between the coating and water in accordance with the national standard GB/T 30693-2014.

Stain resistance: Draw a horizontal line on the coating with an oil-based marker, wipe it with a dry cloth, and observe whether it will leave a mark. The evaluation is divided into 1 to 5 levels, with 1 indicating the lightest mark, which means the best stain resistance, and 5 indicating the heaviest mark and the worst stain resistance.

Table 2, test performance results of the coatings obtained from Examples 1-5 of the present invention and Comparative Examples 1-3

From the performance test results in Table 2, it can be seen that compared with Comparative Examples 1 and 3, the haze of the paint film prepared by the silicone-modified hydroxy acrylate dispersion of Examples 1-5 of the present invention is significantly reduced, that is, after adding silicone monomer a, the change in the haze, i.e., permeability of the paint film, shows a significant improvement. Silicone monomer b significantly improves the stain resistance/water contact angle of the paint film, and when the amount of silicone monomer a in the ratio is greater than the amount of silicone monomer b (Examples 3-4), the permeability of the paint film will be better.

In comparative example 1, no organosilicon monomer a is added to the dispersion structure, and the hydrophilic component of the dispersion in comparative example 3 is in the form of carboxyl salts. The test results show that the haze of the paint films prepared in these two comparative examples is significantly larger than that of Examples 1-5. This result illustrates the effectiveness of the present invention, that is, after adding organosilicon monomer a, the haze of the paint film, i.e., the change in permeability, shows a significant improvement; the non-ionic hydrophilic structure has a relatively lower polarity, has better compatibility with the organosilicon part, and improves the haze.

In Examples 1 to 3 and Comparative Example 1, the amount of organosilicon intermediate b is the same, there is no organosilicon intermediate a in Comparative Example 1, and the amount of organosilicon intermediate a in the structures of Examples 1 to 3 is increased successively. The haze of the resin shows a significant downward trend, that is, the permeability of the paint film is improved, indicating that the organosilicon intermediate a has a very significant improvement on the haze; and with the increase in the total amount of organosilicon (polyether modified + non-polyether modified), the contact angle, stain resistance and weather resistance of the resin all show an improving trend.

In Examples 2, 4, 5 and Comparative Example 2, the amount of organosilicon intermediate a is fixed, there is no organosilicon intermediate b in Comparative Example 2, and the amount of organosilicon intermediate a in the structures of Examples 2, 4, and 5 is different. From Table 2, as the amount of organosilicon monomer b in the resin structure increases, the haze of the resin shows a significant upward trend, indicating that the organosilicon intermediate b causes the resin haze value to increase significantly; but as the total amount of organosilicon (polyether modified + non-polyether modified) increases, the water contact angle, stain resistance and weather resistance show an improving trend.

Compared with Comparative Example 3, the non-ionic hydrophilic structure of Example 2 has a lower haze value, that is, better permeability, than the ionic structure resin of Comparative Example 3, which indicates that the non-ionic hydrophilic structure has a relatively lower polarity and better compatibility with the silicone part; at the same time, the ionic hydrophilic structure of Comparative Example 3 needs to be neutralized with amine, and is also inferior to the non-ionic hydrophilic structure of the present invention in terms of weather resistance.

Summary: Silicone intermediate a (polyether modified) has a very obvious improvement on the resin haze value (permeability); silicone intermediate b has a relatively more obvious improvement on the stain resistance/water contact angle, but at the expense of the permeability of the paint film; the non-ionic hydrophilic structure is significantly better than the ionic hydrophilic structure in improving the permeability and weather resistance of the resin paint film.

The present invention skillfully combines the characteristics of polyether-modified silicone and non-polyether-modified silicone, and adopts a non-ionic hydrophilic structure. The synthesized silicone-modified hydroxypropylene dispersion achieves a better balance in terms of paint film permeability, water contact angle, stain resistance, weather resistance, etc.

Although this specification describes specific embodiments of the present invention, the present invention is not limited to the specific embodiments disclosed, and it is obvious to those skilled in the art that various changes may be made to the present invention without departing from the scope of the present invention as defined by the claims.

Claims (12)

1. A method for preparing an organosilicon modified hydroxyacrylate dispersion, comprising the steps of:

step S1, preparation of an organosilicon intermediate a and an organosilicon intermediate b: introducing acrylic ester double bond modification into the polyether modified organosilicon monomer (1) to prepare an organosilicon intermediate a; introducing acrylic ester double bond modification into the organosilicon monomer (2) to prepare an organosilicon intermediate b;

step S2, preparing the organosilicon modified hydroxy acrylic resin: taking the organosilicon intermediate a, (methyl) acrylic ester monomer, hydroxyl-containing (methyl) acrylic ester monomer and polyethylene glycol (methyl) acrylic ester monomer as raw materials to obtain a monomer mixture, and taking the organosilicon intermediate b and a solvent as a base material to react under the action of a thermal initiator to obtain organosilicon modified hydroxyl acrylic resin;

step S3, preparing an organosilicon modified hydroxy acrylic ester dispersoid: and (2) adding water into the organosilicon modified hydroxy acrylic resin prepared in the step (S2) at a certain temperature for dispersion, and filtering to obtain the organosilicon modified hydroxy acrylic ester dispersion.

2. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein in said step S1, said polyether-modified silicone monomer (1) and said silicone monomer (2) are 2-hydroxyl-group-containing, epoxy-free silicone monomers.

3. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein in said step S1, the introduction of an acrylate double bond modification in said polyether-modified silicone monomer (1) is effected by an esterification reaction of an acrylic monomer with said polyether-modified silicone monomer (1); and introducing an acrylic ester double bond into the organic silicon monomer (2) for modification through esterification reaction between the acrylic acid monomer and the organic silicon monomer (2).

4. The method for producing a silicone modified hydroxyacrylate dispersion according to claim 1, wherein in said step S2, said solvent in said primer is propylene glycol butyl ether.

5. The method for preparing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein, in the step S3, the temperature of the silicone-modified hydroxyacrylate resin is lowered to 60-100 ℃ upon dispersion by adding water; and, the moisture is added in three portions.

6. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 1 wherein,

The monomer mixture comprises the following raw materials in parts by weight:

1 to 10 parts of the organosilicon intermediate a,

25 To 40 parts of the (meth) acrylate monomer,

25 To 35 parts of the hydroxyl group-containing (meth) acrylate monomer,

10 To 30 parts of the polyethylene glycol (meth) acrylate monomer, and

1-3 Parts of the thermal initiator; and

The base material comprises the following components in parts by weight:

1 to 5 parts of said silicone intermediate b, and

5-10 Parts of the solvent.

7. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein in said step S1, said polyether-modified silicone monomer (1) is selected from at least one of X-22-4952, X-22-4272, KF-6123 or Silok 8530H.

8. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein in said step S1, said silicone monomer (2) is selected from at least one of KF-6000, KF-6001, KF-6002, KF-60004, silok 8550, silok 8807, silok 8812, silok 8814, silok 8815, silok 8865H, silok 8866F1 or Silok 8832F 2.

9. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 3, wherein the molar ratio of the acrylic acid monomer to the polyether-modified silicone monomer (1) for the esterification reaction is 1:0.5 to 1:2.

10. The method for producing a silicone-modified hydroxyacrylate dispersion according to claim 3, wherein the molar ratio of the acrylic acid monomer to the silicone monomer (2) for the esterification reaction is 1:0.5 to 1:2.

11. The method for preparing a silicone-modified hydroxyacrylate dispersion according to claim 1, wherein in step S2, said polyethylene glycol (meth) acrylate monomer is selected from at least one of polyethylene glycol 400 (meth) acrylate, polyethylene glycol 600 (meth) acrylate, polyethylene glycol 800 (meth) acrylate, polyethylene glycol 1000 (meth) acrylate, polyethylene glycol 1500 (meth) acrylate, polyethylene glycol 2000 (meth) acrylate or polyethylene glycol 3000 (meth) acrylate.

12. A silicone modified hydroxy acrylate dispersion having a pH of 6.5 to 8.0, a particle size of 80nm to 250nm, a solids content of 38% to 45% and a hydroxy content of 3.8% to 4.5% produced by the process according to claims 1 to 11.