CN102294851A - Hydrophobic scratch-resistant coating on organic polymer surface and preparation method thereof - Google Patents

Abstract

The invention relates to a hydrophobic scratch-resistant coating on the surface of an organic polymer and a preparation method thereof. The coating is a double-layer coating, and the first layer (bottom layer) is composed of 30-70% organic-inorganic hybrid resin, 20- The organic-inorganic hybrid coating composed of 50% oligomer, 5-25% reactive diluent, 1-2% photoinitiator and 0.2-3% additive is formed by UV curing; the second layer (top layer ) includes particles hydrophobically modified with an unsaturated double bond-containing organosilicon monomer, which particles are immobilized by a UV-curable resin. The coating has the characteristics of strong adhesion, high hardness, and good hydrophobicity, and can be used for coating protection of organic polymer surfaces.

Description

Hydrophobic scratch-resistant coating on organic polymer surface and preparation method thereof

technical field

The invention relates to an ultraviolet light-curable coating material, in particular to a hydrophobic scratch-resistant organic-inorganic hybrid ultraviolet light-curable coating and a coating preparation method, which are specifically used for plastic surfaces.

Background technique

Organic polymer materials have many excellent properties, such as processing performance, weather resistance, good electrical insulation, excellent optical properties, and are light and tough. They have been widely used in agriculture, aviation, construction, transportation, optical instruments and other fields. With the development of science and technology, this material has been applied in new high-end products, such as new organic displays, optical lenses and devices, high-grade decorative materials, sound barriers, aviation windows, high-speed rail train windows, organic biological containers, advanced packaging materials etc. However, compared with glass, there are still some disadvantages, such as poor scratch resistance, easy to combine with oil and difficult to clean. In order to give full play to the advantages of organic polymer materials, overcome the disadvantages of easily scratched and difficult to clean materials, and expand the service life and application range of materials, people have conducted extensive research on this.

In order to improve the scratch resistance of the surface of organic polymers, researchers mostly use nanotechnology and have achieved good results. CN1772820A reported that adding 0.1~8.0% wear-resistant-hardness additives in traditional UV-curable coatings can improve the wear resistance of coatings to a certain extent, but there is a problem of incompatibility between inorganic fillers and resins, which even leads to Macroscopic phase separation, the improvement of wear resistance is not obvious, and the transmittance decreases. CN101045833A has reported a kind of preparation method of in-situ modification UV-curable coating, and this method selects one or several kinds of acrylic ester reactive diluents with lower viscosity as the matrix of in-situ reaction, adopts orthosilicate as precursor Using silane coupling agent with amino groups as catalyst and surface treatment agent, the preparation and surface treatment of nanomaterials can be completed in one step, and then UV-curable coatings can be prepared. Capacitance and easy agglomeration of nanoparticles. However, none of the above studies considered the ease of cleaning of the coating film.

In terms of improving the cleanability of organic polymer surfaces, researchers have invented many methods to prepare superhydrophobic coatings, mainly including template method, particle filling method, etching method, nanoarray method, vapor deposition method, phase separation method, sol -Gel method, photochemical method, etc. The main preparation idea is to construct a micro-nano rough structure on the surface to make the surface super-hydrophobic. With the deepening of superhydrophobic research recently, the disadvantages and fatal shortcomings of obtaining surface microstructure through various methods have become more and more prominent. Although a thin film or surface with a micro-nano composite structure has a contact angle greater than 150° and a low hysteresis effect, such a thin film or surface has poor mechanical strength and is easy to fall off.

Contents of the invention

In order to solve the above shortcomings, the present invention provides a method for preparing a hydrophobic scratch-resistant coating on the surface of an organic polymer. This method has the advantages of low cost and simple process. The coating has strong adhesion, high hardness and good hydrophobicity. And other characteristics, can be used for coating protection of organic polymer surface.

The hydrophobic scratch-resistant coating on the surface of an organic polymer proposed by the present invention comprises an organic-inorganic hybrid paint cured by UV-cured scratch-resistant bottom layer and a hydrophobic top layer, the bottom layer adheres to the surface of the organic polymer, and the hydrophobic top layer Comprising particles hydrophobically modified with silicone monomers containing unsaturated double bonds, the particles are immobilized by UV-curable resins.

The organic polymer proposed in the present invention is one of polymethyl methacrylate (PMMA), polycarbonate (PC) and polyethylene terephthalate (PET).

The organic-inorganic hybrid coating used in the scratch-resistant bottom layer proposed by the present invention, the components of the coating and their weight percentages are as follows:

                             

Organic-inorganic hybrid resin 30-70

Oligomers 20-50

Active diluent 5-25

Photoinitiator 1-2

Auxiliary 0.2-3

The oligomer proposed in the present invention can be selected from one or more of polyurethane acrylate, bisphenol A epoxy acrylate and polyester acrylate.

The active diluent proposed by the present invention is 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trihydroxy One or more of methyl propane triacrylate.

The organic-inorganic hybrid resin proposed by the present invention is made from the following components:

Components Weight Percentage wt%

Alkoxysilane 10-20

Silicone monomer containing unsaturated double bond 20-50

Silica sol 2-20

Solvent 10-20

Water 5-20

Acid catalyst 0.01-1

The specific preparation method is: first add alkoxysilane, organosilicon monomer and solvent containing unsaturated double bonds to the reactor, drop the mixture of water, silica sol and acidic catalyst within 0.5-1 hour, stir and react 6-8 Hours later, it was aged for 24 hours to obtain an organic-inorganic hybrid resin.

The coating used for the hydrophobic top layer proposed by the present invention is made from the following components:

Components Weight Percentage wt%

Hydrophobically modified particle suspension 45-70

UV curable resin 0.2-10

Solvent 30-50

Photoinitiator 1-2

Auxiliary 0.2-3

The specific preparation process is as follows: uniformly mixing and stirring the hydrophobic modified particle suspension, the ultraviolet curable resin, the solvent, the photoinitiator and the auxiliary agent to prepare the ultraviolet curable coating for the top layer coating.

The hydrophobically modified particle suspension proposed by the present invention is prepared from the following components:

Components Weight Percentage wt%

Alkoxysilane 10-17

Fluorosiloxane 1-3

Silicone monomer containing unsaturated double bond 0.2-5

Solvent 75-85

Basic catalyst 2.5-2.7

The specific preparation process is as follows: firstly add tetraethyl orthosilicate, organosilicon monomer containing unsaturated double bonds, fluorine-containing siloxane and ethanol in the reactor, and drop the mixture of water and basic catalyst within 0.5-1 hour, After stirring and reacting for 20 hours, a suspension of hydrophobically modified particles was obtained.

The fluorine-containing siloxane proposed in the present invention is tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane and heptadecafluorodecyltriethoxysilane One of the silanes.

The UV-curable resin proposed by the present invention is a mixture of oligomer and reactive diluent in the primer.

The coating preparation technology that the present invention proposes, comprises the steps:

(1) First weigh the organic-inorganic hybrid resin, oligomer, reactive diluent, photoinitiator, and additives; then stir and mix the weighed components together to obtain the paint for the bottom coating, and use a brush to It is directly coated on the surface of the substrate by means of coating, spraying or shower coating. After leveling, it is cured by direct ultraviolet radiation with a high-pressure mercury lamp to form a semi-cured bottom layer.

(2) Weigh the resin, hydrophobic modified particle suspension, photoinitiator, and solvent first; then stir and mix the weighed components together, and spray them directly on the semi-cured bottom layer.

(3) After the surface is heated to 70-100°C to volatilize the solvent, the bottom layer and the top layer are cured by direct ultraviolet radiation using a high-pressure mercury lamp to obtain a scratch-resistant hydrophobic coating.

In the coating preparation process proposed by the present invention, since the surface of the hydrophobically modified particles in the top layer contains UV-curable unsaturated double bonds, during the crosslinking and curing process of the resin, the hydrophobically modified particles in the top layer are firmly fixed on its surface. Dispersed in the resin matrix and then covalently bonded to the underlying resin, the coating can be viewed as a single continuous resin layer with hydrophobically modified particles embedded in its surface.

The hydrophobic scratch-resistant coating prepared by the present invention has the following advantages: organic-inorganic is hybridized in the range of nanometer size, the prepared coating has strong adhesion, high hardness, good hydrophobicity and other properties, and the coating is in contact with water The angle is more than 130°.

The hydrophobic scratch-resistant coating provided by the invention can be used for finishing and protecting the surface of organic polymers.

Description of drawings

Figure 1 is a state diagram of the water contact angle of the coating surface obtained in Example 10.

Detailed ways

The present invention is further described in detail below in conjunction with examples, but is not limited thereto.

1. Preparation of organic-inorganic hybrid resin

Example 1:

In a reactor equipped with a stirrer and a dropping funnel, add 46.8g of ethyl orthosilicate, 168g of γ-methacryloxytrimethoxysilane, and 53.7g of ethanol, stir at room temperature for 10 minutes, mix 9g of silica sol, 0.4 1 g of nitric acid and 58.5 g of water were evenly mixed and placed in a dropping funnel, added dropwise in 0.5-1 hour, stirred for 6-8 hours, and aged for 24 hours to obtain an organic-inorganic hybrid resin.

Example 2:

In a reactor equipped with a stirrer and a dropping funnel, add 46.8g of tetraethyl orthosilicate, 168g of γ-methacryloxytrimethoxysilane, and 53.7g of ethanol, stir at room temperature for 10 minutes, mix 18g of silica sol, 0.41 1 g of nitric acid and 52.2 g of water were evenly mixed, placed in a dropping funnel, added dropwise in 0.5-1 hour, stirred and aged for 6-8 hours, and aged for 24 hours to obtain an organic-inorganic hybrid resin.

2. Preparation of organic-inorganic hybrid UV-curable coatings for bottom coating

Example 3:

Resin 97.5g, polyurethane acrylate 11.2g, epoxy acrylate 8.4g, trimethylolpropane triacrylate 8.4g, photoinitiator Darocur 1173 1.12g, leveling agent 0.38g that embodiment 1 makes, mix Stir evenly to prepare an organic-inorganic hybrid paint.

Example 4:

The resin 17.9g that embodiment 1 makes, polyurethane acrylate 11.2g, epoxy acrylate 8.4g, trimethylolpropane triacrylate 8.4g, photoinitiator Darocur 1173 1.12g, leveling agent 0.14g, mix Stir evenly to prepare an organic-inorganic hybrid paint.

Example 5:

93g of resin, 11.2g of polyurethane acrylate, 8.4g of epoxy acrylate, 8.4g of trimethylolpropane triacrylate, 1.12g of photoinitiator Darocur 1173, and 0.39g of leveling agent obtained in Example 2 were mixed and stirred Uniform, organic-inorganic hybrid coatings are prepared.

Embodiment 6:

The resin 69.2g that embodiment 2 makes, polyurethane acrylate 19.1g, epoxy acrylate 14.3g, trimethylol propane triacrylate 14.3g, photoinitiator Darocur 1173 1.20g, leveling agent 0.35g, mix Stir evenly to prepare an organic-inorganic hybrid paint.

3. Preparation of hydrophobically modified particles

Embodiment 7:

In a reactor equipped with a stirrer and a dropping funnel, add 4.7 g of tetraethyl orthosilicate, 1.37 g of ammonia water, and 39.5 g of ethanol, stir at room temperature for 10 minutes, and add 1.15 g of tridecafluorooctyltriethoxysilane, 2.8 g of γ-methacryloyloxytrimethoxysilane, mixed evenly, placed in a dropping funnel, added dropwise in 0.5-1 hour, stirred for 20-24 hours, ultrasonicated for 15 minutes, to obtain hydrophobically modified nanoparticles.

4. Preparation of UV-curable coating for top coat

Embodiment 8:

60g of hydrophobically modified particles, 0.08g of polyurethane acrylate, 0.06g of epoxy acrylate, 0.06g of trimethylolpropane triacrylate, 39.8g of ethanol, 0.008g of photoinitiator Darocur 1173, and fluid 0.3 g of the leveling agent was mixed and stirred evenly to obtain a UV-curable coating for the top coat.

Embodiment 9:

60g of hydrophobically modified particles, 0.24g of polyurethane acrylate, 0.18g of epoxy acrylate, 0.18g of trimethylolpropane triacrylate, 39.4g of ethanol, 0.024g of photoinitiator Darocur 1173, and fluid 0.3 g of the leveling agent was mixed and stirred evenly to obtain a UV-curable coating for the top coat.

5. Preparation of hydrophobic scratch-resistant coating

Example 10:

Use the organic-inorganic hybrid UV-curable coating for the bottom coating prepared in Example 6 respectively, and apply it to the PMMA substrate by spraying. A semi-cured bottom layer is formed. Then the top coating prepared by Example 8 is sprayed onto the semi-cured bottom layer with UV-curable paint, baked at 70-100° C. for 5-10min, after volatilizing the solvent, adopt high-pressure mercury lamp direct ultraviolet radiation to cure the bottom layer and The top layer, gets a scratch-resistant hydrophobic coating.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (11)

1. Hydrophobic scratch-resistant coating on the surface of an organic polymer, characterized in that the coating comprises an organic-inorganic hybrid coating through a UV-cured scratch-resistant bottom layer and a hydrophobic top layer, and the scratch-resistant bottom layer adheres to the organic A polymer surface, the hydrophobic top layer comprising particles hydrophobically modified with an unsaturated double bond-containing silicone monomer, the particles being fixed by a UV-curable resin. 2. The organic polymer according to claim 1 is polymethyl methacrylate, polycarbonate, the one in polyethylene terephthalate. 3. The hydrophobic scratch-resistant coating on the surface of an organic polymer according to claim 1, characterized in that the organic-inorganic hybrid coating used in the scratch-resistant bottom layer, each component of the coating and its weight percentage as follows:                               Organic-inorganic hybrid resin 30-70 Oligomers 20-50 Active diluent 5-25 Photoinitiator 1-2 Auxiliary 0.2-3. 4. The hydrophobic scratch-resistant coating on organic polymer surfaces according to claim 3, wherein said oligomer is selected from one of polyurethane acrylate, bisphenol A epoxy acrylate, and polyester acrylate. species or several. 5. The hydrophobic scratch-resistant coating on organic polymer surface according to claim 3, characterized in that the reactive diluent is 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, trihydroxy One or more of methylpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate. 6. The hydrophobic scratch-resistant coating on the surface of an organic polymer according to claim 3, wherein the organic-inorganic hybrid resin is made from the following components: Components Weight Percentage wt% Alkoxysilane 10-20 Silicone monomer containing unsaturated double bond 20-50 Silica sol 2-20 Solvent 10-20 Water 5-20 Acid catalyst 0.01-1 The preparation method is as follows: firstly add alkoxysilane, organosilicon monomer containing unsaturated double bond and solvent into the reactor, add dropwise the mixture of water, silica sol and acidic catalyst within 0.5-1 hour, stir and react for 6-8 Hours later, it was aged for 24 hours to obtain an organic-inorganic hybrid resin. 7. The hydrophobic scratch-resistant coating on organic polymer surface according to claim 1, characterized in that the used coating for the hydrophobic top layer is made from the following components: Components Weight Percentage wt% Hydrophobically modified particle suspension 45-70 UV curable resin 0.2-10 Solvent 30-50 Photoinitiator 1-2 Auxiliary 0.2-3 The specific preparation process is as follows: uniformly mixing and stirring the hydrophobic modified particle suspension, the ultraviolet curable resin, the solvent, the photoinitiator and the auxiliary agent to prepare the ultraviolet curable coating for the top layer coating. 8. The hydrophobic scratch-resistant coating on the surface of an organic polymer according to claim 1, characterized in that the suspension of the hydrophobically modified particles is made from the following components: Components Weight Percentage wt% Alkoxysilane 10-17 Fluorosiloxane 1-3 Silicone monomer containing unsaturated double bond 0.2-5 Solvent 75-85 Basic catalyst 2.5-2.7 The specific preparation process is as follows: firstly add tetraethyl orthosilicate, organosilicon monomer containing unsaturated double bonds, fluorine-containing siloxane and ethanol in the reactor, and drop the mixture of water and basic catalyst within 0.5-1 hour, After stirring and reacting for 20 hours, a suspension of hydrophobically modified particles was obtained. 9. The hydrophobic scratch-resistant coating on the surface of an organic polymer according to claim 7, characterized in that the fluorine-containing siloxane is tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxy One of base silane, heptadecafluorodecyltrimethoxysilane and heptadecafluorodecyltriethoxysilane. 10. The hydrophobic scratch-resistant coating on organic polymer surfaces according to claim 7, characterized in that the UV-curable resin in the top layer is a mixture of oligomers and reactive diluents in the primer. 11. A method for preparing a hydrophobic scratch-resistant coating on an organic polymer surface, characterized in that the method comprises the steps of: a) First weigh the organic-inorganic hybrid resin, oligomer, reactive diluent, photoinitiator, auxiliary agent according to the formula described in claim 3; then stir and mix the weighed components evenly, and apply by brush , Spray or flow coating directly on the surface of the substrate, after leveling, use a high-pressure mercury lamp to directly cure with ultraviolet radiation to form a semi-cured bottom layer; b) First weigh the resin, hydrophobically modified particles, photoinitiator, and solvent according to the formula described in claim 7; then stir and mix the weighed components evenly, and apply spraying directly on the semi-cured bottom layer ; c) After the surface is heated to 70-100°C to volatilize the solvent, the bottom layer and the top layer are cured by direct ultraviolet radiation using a high-pressure mercury lamp to obtain a scratch-resistant hydrophobic coating.