CN109868026B - Organic silicon modified acrylate resin, preparation method thereof and hydrophobic weather-resistant slow-release modified acrylic resin coating - Google Patents

Abstract

The invention discloses an organic silicon modified acrylate resin, a preparation method thereof and a hydrophobic weather-resistant slow-release modified acrylate resin coating. Hydrolyzing and condensing organic siloxane to obtain organic silane oligomer, prepolymerizing the organic silane oligomer with partial acrylic resin polymerized monomers, and polymerizing the organic silane oligomer with the rest acrylic resin polymerized monomers to obtain organic silicon modified acrylic resin; the organic silicon modified acrylate resin, the isocyanate curing agent, the filler, the solvent, the auxiliary agent and the like are compounded, so that the integrated protective material with good hydrophobicity, high temperature resistance, weather resistance and corrosion resistance can be obtained.

Description

A kind of organosilicon modified acrylate resin and preparation method thereof and hydrophobic weather resistance slow release Modified acrylic resin coating

technical field

The invention relates to an organosilicon-modified acrylate resin and a preparation method thereof, and also relates to a hydrophobic weather-resistant slow-release coating using an organosilicon-modified acrylic resin as a matrix resin, belonging to the field of coatings.

Background technique

As a commonly used important chemical product, coatings are widely used in construction, aviation, ships, automobiles, and almost all walks of life, and play functional roles such as appearance decoration, weather resistance and corrosion resistance. With the development of engineering technology, special working environments are becoming more and more common, and coatings used in harsh environments have become an important research content. As the basic part of organic coatings, the research and development of resins that can be used as protective materials with high temperature resistance, multi-purpose and excellent performance has become the focus of research in recent years.

Acrylic resin has the advantages of light color, high transparency, good corrosion resistance, small absorption in the infrared region, many monomers, and low price, but its lack of high and low temperature resistance, water resistance and air permeability limit further applications. The silicone resin has the characteristics of both inorganic and organic compounds, and is a kind of polymer material with dual properties. Silicone monomers and their polymers have high Si-O bond energy and easy bond rotation, endow them with lower surface tension and glass transition temperature, and have excellent water resistance, temperature resistance, weather resistance and other excellent properties, but Due to its low polarity, it has poor adhesion on general substrates and is relatively expensive. Using silicone to modify polyacrylic resin is expected to obtain a composite material with both advantages, improve the performance of the material, and expand the scope of use. At present, the research on silicone modified acrylic resin is generally divided into mechanical blending and chemical modification. The mechanical blending method is simple to operate, but the organic silicon is quite different from acrylate in structure and polarity, which is manifested in the large difference in surface free energy and poor compatibility. After blending, the silicone is easy to migrate to the surface. The silicone-modified acrylate polymer is prone to phase separation, and it is difficult to obtain a stable and uniform silicone-acrylic resin. Chemical modification is to form a chemical bond to combine these two polymers with different polarities through a chemical reaction, and introduce the silicone molecular chain into the acrylate molecule. The chemical modification method mainly introduces polysilane into acrylate by grafting, which can inhibit the migration of organosilicon molecules to the surface to a certain extent, thereby improving the compatibility between the two. It is quite different from acrylate in polarity and has poor compatibility, and there is still a phase separation phenomenon. In addition, the hydrophobicity, high temperature resistance, weather resistance, etc. of the existing organosilane-modified acrylates are improved, but the anticorrosion performance is poor.

SUMMARY OF THE INVENTION

Aiming at the technical problems existing in the silicone-modified acrylate polymers in the prior art, the first object of the present invention is to provide a functional monomer that simultaneously contains unsaturated double bonds and hydrolyzable condensed groups to The method for obtaining the organosilicon modified acrylic resin with stable and uniform structure, good compatibility between organosilane and polyacrylate, and difficult phase separation by copolymerizing organosilane oligomer and acrylic monomer is simple in operation and low in cost. Conducive to industrial production.

The second object of the present invention is to provide an organosilicon-modified acrylic resin with good compatibility between organosilane and polyacrylate and not easy to phase-separate. The resin has good hydrophobicity, high temperature resistance, weather resistance and Anti-corrosion properties, suitable for hydrophobic, weather-resistant and slow-release integrated protective materials.

The third object of the present invention is to provide a hydrophobic and weather-resistant slow-release integrated protective coating with good coating hydrophobicity, high temperature resistance, weather resistance and corrosion resistance.

In order to achieve the above technical purpose, the present invention provides a method for preparing an organosilicon modified acrylate resin. The method comprises the steps of hydrolyzing and condensing an organosiloxane to obtain an organosilane oligomer, first mixing the organosilane oligomer with part of acrylic acid The resin polymerizable monomer is prepolymerized, and then polymerized with the remaining part of the acrylic resin polymerized monomer to obtain the silicone modified acrylic resin; the acrylic resin polymerized monomer includes soft monomer, hard monomer and functional monomer; the hard monomer The monomer includes at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, styrene, acrylonitrile, and acrylic acid; the soft monomer includes ethyl acrylate At least one of ester, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate, n-octyl methacrylate; the functional monomer includes 2-hydroxyethyl acrylate , at least one of 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate.

The key to the technical solution of the present invention lies in the use of special functional monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. Participate in the copolymerization of organosilane oligomers and acrylate monomers. These functional monomers not only contain double bond functional groups but also hydroxy ester groups, which can be hydrolyzed and condensed with organosilanes, and can be free-radically polymerized with acrylate monomers, which are dispersed in the polyacrylic resin through random copolymerization, It can also be condensed and cross-linked with organosilane oligomers, so as to have a good coupling effect, thereby improving the compatibility of organosilicon and polyacrylate, and obtaining stable organosilicon modified acrylic resin.

In a preferred solution, the organosiloxane includes at least one of monomethyltriethoxysilane, dimethyldiethoxysilane, vinyltriethoxysilane, and phenyltriethoxysiloxane .

In a preferred solution, the organosiloxane is uniformly mixed according to the R/Si value of 1.2 to 1.4 and the Ph/R value of 0.2 to 0.6, then the acidic solution is added dropwise, and the reaction is carried out at a temperature of 70 to 80 ° C for 3 to 6 hours to obtain the organic siloxane. Silane oligomers. Wherein, R is the number of alkyl groups directly connected to the silicon atom, and Ph is the number of phenyl groups directly connected to the silicon atom. The R/Si value can estimate the curing speed, linear structure and flexibility of the resin, and the Ph/Si value imparts different characteristics to the silicone resin. In the present invention, the R/Si value is preferably 1.2-1.4, and the Ph/R value is 0.2-0.6, so as to obtain a silicone resin with excellent performance.

In a preferred solution, the mass ratio of the organosilane oligomer to the soft monomer, the hard monomer and the functional monomer is 15-30:20-50:40-70:5-25. The silicone-modified acrylic resin with the best comprehensive properties can be obtained within the preferred ratio range.

In a preferred solution, the organosilane oligomer and 30-50% mass of acrylic resin polymerized monomers are polymerized at 75-85 °C for 1-2 hours, and then the remaining part of the acrylic resin polymerized monomers are polymerized within 1.5-2 hours. The organic silicon modified acrylic resin is obtained by uniformly adding dropwise to the reaction system and maintaining the reaction temperature for 0.5 to 1.5 hours. In the polymerization process, a conventional initiator is used, and the addition of the initiator is mixed with the acrylic resin polymerization monomer.

The present invention also provides an organosilicon modified acrylate resin obtained by the above preparation method.

The present invention also provides a hydrophobic weather-resistant slow-release modified acrylic resin coating, which comprises the above-mentioned organosilicon modified acrylic resin, an isocyanate curing agent, a filler, a solvent and an auxiliary agent.

In a preferred solution, the filler is silane-modified nanoparticles; the silane-modified nanoparticles include at least one of silane-modified nano-silica, silane-modified nano-titania, and silane-modified nano-zinc oxide. The present invention adopts silane-modified nano-particles as fillers, and by silane-modifying the surface of common nano-particles, the two-phase interface effect can be effectively reduced, agglomeration can be reduced, and the stability of inorganic nanoparticles in organic resins can be improved. The preparation method of the silane-modified nanoparticles of the present invention: disperse the inorganic nanoparticles into a mixed solution of ethanol, water and glacial acetic acid with a pH of 4-5, and stir and react at a temperature of 70-90° C. for 8-16 hours to obtain silane Modified nanoparticles. The particle size of nanoparticles is generally 10 to 100 nm.

A preferred solution is a hydrophobic weather-resistant and slow-release modified acrylic resin coating, comprising the following components in parts by mass: 75-100 parts of silicone modified acrylate resin; 10-20 parts of isocyanate curing agent; 1-10 parts of filler; 30-50 parts of solvent; 2-8 parts of auxiliary agent.

In a preferred solution, the isocyanate curing agent is selected from at least one of Desmodo N75, Desmodo N3390 and BASF HI100ap.

In a preferred solution, the solvent is selected from at least one of butyl acetate, ethyl acetate, toluene, xylene, and propylene glycol methyl ether acetate.

In a preferred solution, the auxiliary agent can be selected from at least one of BYK series leveling agents, defoaming agents, wetting agents and dispersing agents. Additives are commonly used in the field of coatings, such as those that play the roles of leveling, defoaming, pigment wetting, and viscosity adjustment.

A preparation method of a hydrophobic weather-resistant slow-release modified acrylic resin coating of the present invention comprises the following steps:

1) hydrolyzing and condensing the organosiloxane to obtain an organosilane oligomer;

2) prepolymerizing part of acrylic resin polymer monomers and organosilane oligomers, and then polymerizing with remaining part of acrylic resin polymer monomers to obtain organosilicon modified acrylic resin;

3) adding silane coupling agent KH-570 dropwise to the nanoparticle dispersion to react to obtain silane-modified nanoparticles;

4) uniformly mixing the polysilane-modified acrylic resin and the silane-modified nanoparticles to obtain the organosilicon-modified acrylate resin and the nanoparticle composite;

5) Mix the organosilicon-modified acrylate resin and the nanoparticle composite with the isocyanate curing agent, solvent and auxiliary, and then obtain.

Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

The technical scheme of the present invention utilizes a functional monomer containing both a double bond functional group and a hydroxyl ester group in the preparation process of the organosilicon modified acrylate resin. Radical polymerization, which is dispersed in polyacrylic resin through random copolymerization, and can be condensed and cross-linked with organosilane oligomers to obtain stable silicone-modified acrylic resin and improve the compatibility of silicone and polyacrylate .

The organosilicon-modified polyacrylic resin obtained by the technical solution of the present invention has excellent hydrophobicity and heat resistance, as well as lower surface energy, better antifouling property and adhesion to metal.

The coating formulation obtained by the organosilicon-modified acrylate resin and organosilicon-modified nano-particles, conventional curing agents, auxiliary agents, etc., has excellent hydrophobicity, heat resistance, anti-corrosion performance and mechanical properties at the same time.

Description of drawings

Fig. 1 is the infrared spectrogram of acrylic resin and organosilicon modified acrylic resin;

Fig. 2 is the thermogravimetric diagram of acrylic resin and silicone modified acrylic resin;

Fig. 3 is the contact angle diagram of acrylic resin and organosilicon modified acrylic resin;

Figure 4 is the chemical impedance spectrum of the coating after soaking for 600h and 1800h.

Detailed ways

The following examples are intended to further illustrate the content of the present invention, rather than limit the protection scope of the claims of the present invention.

Example 1

① Preparation of silicone oligomers

The monomer 19.20g phenyltriethoxysilane, 11.84g dimethyldiethoxysilane, 7.62g vinyltriethoxysilane mixed solution was added to the reactor, stirred and heated to 80°C, slowly dripping Add 9.36g of distilled water and 0.09g of hydrochloric acid mixed solution as the hydrolysis raw material and catalyst. After the dropwise addition, the constant temperature reaction was performed for 5h, and then the vacuum distillation was started, and the pressure was controlled at 0.06MPa, and the small molecules and water produced during the reaction were evaporated. After cooling to room temperature, the pH was adjusted to neutrality with ammonia water to obtain an organosilicon oligomer.

② Preparation of silicone modified acrylic resin

6.25 g of the silicone prepolymer was poured into a three-necked flask, and 20 g of a solvent (ethyl acetate:butyl acetate=1:1) was added. After stirring and heating to 70°C, acrylic acid mixed monomers (8.2g methyl methacrylate, 5.3g butyl acrylate, 0.3g acrylic acid, 7.3g styrene, 4.5g methacrylate-β-hydroxyethyl ester) were added dropwise and initiator 0.25g azobisisobutyronitrile (the initiator has been dissolved in the mixed monomer), and the dropwise addition is completed in about 90min. After the temperature was raised to 80 °C, the reaction was performed at a constant temperature for 1 h, and the material was discharged.

③ Preparation of organically modified nano _- SiO

Disperse 5g of nano-SiO ₂ (20nm) in 300g of solvent (ethanol: water = 3:1), add it to the reactor, disperse it evenly at high speed, and slowly add 0.5g of γ-methacryloyloxypropyltrimethoxysilane dropwise, The reaction was refluxed in a water bath at 70° C. for 8 hours, and after cooling to room temperature, the product was centrifuged and washed with ethanol to obtain organically modified nano-SiO ₂ .

④Paint

Add 80 parts of organosilicon modified acrylic resin and 4 parts of organically modified nano-SiO ₂ to the disperser for dispersion, and add 30 parts of mixed solvent (butyl acetate: toluene: propylene glycol methyl ether acetate = 3:3:2) as Thinner, after dispersing evenly, add 16 parts of N75 curing agent (hexamethylene diisocyanate), and a total of 3 parts of BYK series wetting agent, leveling agent and defoamer, and then evenly coat it on tinplate and keep it constant temperature cured.

Example 2

① Preparation of silicone oligomers

The monomer 38.4g phenyltriethoxysilane, 23.68g dimethyldiethoxysilane, and 15.20g vinyltriethoxysilane mixed solution were added to the reactor, stirred and heated to 80°C, slowly dripping Add 26.2g of distilled water and 0.17g of hydrochloric acid mixed solution as the hydrolysis raw material and catalyst, after the dropwise addition, and then constant temperature reaction for 6h, start vacuum distillation, the pressure is controlled at 0.06MPa, and the small molecules and water produced in the reaction process are evaporated. After cooling to room temperature, the pH was adjusted to neutrality with ammonia water to obtain an organosilicon oligomer.

② Preparation of silicone modified acrylic resin

6 g of the silicone resin prepolymer was poured into a three-necked flask, and 20 g of a solvent (ethyl acetate:butyl acetate=1:1) was added. After stirring and heating to 70°C, acrylic acid mixed monomers (7.4g methyl methacrylate, 8.4g butyl acrylate, 0.5g acrylic acid, 6.6g styrene, 4.8g methacrylate-β-hydroxyethyl ester) were added dropwise and the initiator azobisisobutyronitrile (the initiator has been dissolved in the mixed monomer), and the dropwise addition is completed in about 90 minutes. After the temperature was raised to 80 °C, the reaction was performed at a constant temperature for 1 h, and the material was discharged.

③ Preparation of organically modified nano- _TiO2

Disperse 5g of nano-TiO ₂ (25nm) in 300g of solvent (ethanol: water = 3:1), add it to the reactor, disperse it evenly at high speed, and slowly add 0.5g of γ-methacryloyloxypropyltrimethoxysilane dropwise, The reaction was refluxed in a water bath at 70° C. for 8 hours, and after cooling to room temperature, the product was centrifuged and washed with ethanol to obtain organically modified nano-TiO ₂ .

④Paint

Add 80 parts of organosilicon modified acrylic resin and 5 parts of organically modified nano-TiO ₂ into the dispersing machine to disperse, and add 35 parts of mixed solvent (butyl acetate: toluene: propylene glycol methyl ether acetate = 3:3:2) as Diluent, after dispersing evenly, add 18 parts of N75 curing agent (hexamethylene diisocyanate), and a total of 4 parts of BYK series wetting agent, leveling agent and defoaming agent, then evenly coat the tinplate and keep the temperature constant. cured.

Example 3

Organosilicon-modified acrylic resin and nano-modified SiO ₂ were prepared as steps ① and ② in Example 1.

Add 80 parts of resin and 5 parts of organically modified mixed nanoparticles into a disperser for dispersion, and add 35 parts of mixed solvent (butyl acetate:toluene:propylene glycol methyl ether acetate=5:3:2) as a diluent, to be dispersed After uniformity, add 16 parts of N75 curing agent (hexamethylene diisocyanate), and a total of 4 parts of BYK series wetting agent, leveling agent and defoaming agent, then evenly coat the tinplate and conduct constant temperature curing.

Table 1 Performance test results of the samples obtained in Examples 1 to 3

It can be seen from Figure 1 that the silicone has been successfully grafted to the acrylic resin. As can be seen from Figure 2, the initial decomposition temperature and the maximum decomposition rate of the silicone-modified acrylic resin are both increased, and the thermal weight loss of the silicone-modified acrylic resin is 5% and the maximum weight loss rate temperature is 320 ° C and 428 ° C, respectively. , compared with the pure acrylic resin at 302 °C and 405 °C, which are increased by 18 °C and 23 °C, respectively, indicating that the heat resistance of acrylic resin can be improved after silicone modification. As shown in FIG. 3 , the contact angle of the silicone-modified acrylic resin is significantly higher than that of the unmodified acrylic resin, which is 67.5°, and is 87.5°. After being modified by organosilicon nanoparticles and prepared as a coating, the hydrophobicity and corrosion resistance are both improved. After a series of coatings are prepared as in Example 3, the contact angle is increased to different degrees compared with 87.5° without the addition, and the maximum contact angle reaches 108.4°. The contact angle results show that the addition of silicone nanoparticles can further improve the hydrophobicity of the coating. The corrosion resistance of the coating was measured by electrochemical test. As shown in Figure 4, it can be seen that after immersion for 1800h, the coating impedance of the coating was above 109Ωcm2, maintaining good protective performance.

Claims (8)

1. a preparation method of organosilicon modified acrylate resin, it is characterized in that: organosiloxane is hydrolyzed and condensed to obtain organosilane oligomer, and the acrylic resin polymerized monomer of organosilane oligomer and 30～50% quality After the polymer is polymerized at 75 to 85 °C for 1 to 2 hours, the remaining part of the acrylic resin polymerized monomer is uniformly added dropwise to the reaction system within 1.5 to 2 hours, and the reaction is kept for 0.5 to 1.5 hours to obtain silicone modification. Acrylic; The acrylic resin polymerized monomers include soft monomers, hard monomers and functional monomers; The hard monomer includes at least one of methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, styrene, acrylonitrile, and acrylic acid; The soft monomer includes at least one of ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate, and n-octyl methacrylate; The functional monomer includes at least one of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; The mass ratio of organosilane oligomer to soft monomer, hard monomer and functional monomer is 15-30:20-50:40-70:5-25. 2. The preparation method of an organosilicon modified acrylate resin according to claim 1, wherein the organosiloxane comprises monomethyltriethoxysilane, dimethyldiethoxysilane , at least one of vinyl triethoxy silane and phenyl triethoxy siloxane. 3. the preparation method of a kind of organosilicon modified acrylate resin according to claim 1 and 2, it is characterized in that: organosiloxane according to R/Si value is 1.2～1.4, Ph/R value is 0.2～ 0.6 After mixing evenly, add the acidic solution dropwise, and react at 70-80° C. for 3-6 hours to obtain organosilane oligomers. 4. An organosilicon-modified acrylate resin, characterized in that: obtained by the preparation method according to any one of claims 1 to 3. 5. A hydrophobic weather-resistant slow-release modified acrylic resin coating, characterized in that it comprises the organosilicon modified acrylic resin of claim 4, an isocyanate curing agent, a filler, a solvent and an auxiliary. 6 . The hydrophobic and weather-resistant slow-release modified acrylic resin coating according to claim 5 , wherein the filler is silane-modified nanoparticles; and the silane-modified nanoparticles comprise silane-modified nano-silica. 7 . , at least one of silane-modified nano-titanium dioxide and silane-modified nano-zinc oxide. 7. a kind of hydrophobic weather-resistant slow-release modified acrylic resin coating according to claim 5 or 6, is characterized in that: comprise following mass parts component: 75-100 parts of silicone modified acrylate resin; 10-20 parts of isocyanate curing agent; 1 to 10 parts of filler; 30 to 50 parts of solvent; Auxiliary 2 to 8 copies. 8. a kind of hydrophobic weather-resistant slow-release modified acrylic resin coating according to claim 7, is characterized in that: isocyanate curing agent is selected from at least one in Desmodo N75, Desmodo N3390, BASF HI100ap; The solvent is selected from at least one of butyl acetate, ethyl acetate, toluene, xylene, and propylene glycol methyl ether acetate; The auxiliary agent can be selected from at least one of BYK series leveling agent, defoaming agent, wetting agent and dispersing agent.

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