CN102993938B - Sag prevention polyurethane white finish paint and main paint thereof - Google Patents

Abstract

An anti-sagging polyurethane white finish paint, the main paint of the polyurethane white finish paint, according to the following weight ratio, the components include: short oil alkyd resin 35~50%; 60% mass concentration titanium dioxide slurry 40~50% 55; talc powder 5~8; polyether modified silicone oil leveling agent 0.1~0.5; fumed silica 0.5~5; solvent 1~2. The polyurethane white finish paint provided by the invention has suitable surface tension after the components are combined, and is not easy to sag and bottom out, and even the paint film can change from uneven to flat surface under the action of surface tension.

Description

Anti-sagging polyurethane white finish paint and its main paint

technical field

The invention relates to a polyurethane paint, in particular to a white polyurethane paint without sag phenomenon and its main paint components.

Background technique

Polyurethane paint film is tough, full of luster, strong adhesion, water-resistant, wear-resistant, and corrosion-resistant. It is widely used in high-grade wood furniture coatings, metal surface coatings, electronic coatings, special coatings and other fields.

In the domestic furniture paint market, PU paint still occupies the most important position, among which white series products have the highest share, and among them, two-component polyurethane paint is the most widely used. Two-component polyurethane paint is generally composed of hydroxyl-containing resin (main paint) and isocyanate prepolymer (curing agent). During the construction process, the main paint and isocyanate prepolymer are cross-linked to obtain a polyurethane film. Due to the long reaction process, the paint film dries slowly, so it is easy to have traces of paint liquid flowing down, that is, the phenomenon of sag, especially on vertical surfaces and corners. Therefore, furniture factories often use it during construction operations. The corners will be exposed due to grinding and penetration, and the bottom of the topcoat will be exposed after the construction of the convex paint due to low tension, and the façade spraying will sag, especially in winter when the temperature is low, and the surface drying of the product is more obvious when spraying , greatly reducing work efficiency and product quality. .

Therefore, in order to prevent sagging, it is usually necessary to add a thixotropic agent to the polyurethane paint. The first thixotropic agent is a mineral filler, such as calcium carbonate, bentonite, colloidal silica, etc. The second thixotropic agent is Organic compounds such as hydrogenated castor oil, aliphatic amide waxes, polytetrafluoroethylene, etc. These thixotropic agents must be added in large amounts during use to increase the sag resistance. Therefore, the apparent viscosity of polyurethane increases during the application process, which is not conducive to the coating film. Moreover, the storage of polyurethane paint containing these thixotropic agents is usually Poor stability; the third type of thixotropic agent is amine compound, such as polyoxyalkylene polyamine, aliphatic naphthenic diamine, etc., but polyisocyanate and amine are mixed to produce thixotropy. It takes a few seconds or even a few minutes, requiring high work Not practical for efficient high pressure application.

Visible, still need a kind of polyurethane paint that can reduce or eliminate sagging phenomenon as far as possible.

Contents of the invention

Aiming at the disadvantages of sag and exposed bottom when the polyurethane topcoat is sprayed on corners, convex substrates and facades, the invention provides an anti-sag polyurethane white topcoat and its main paint components.

The first object of the present invention is to provide a kind of anti-sag polyurethane white finish main paint.

The main paint of the anti-sag polyurethane white finish paint, according to the following weight ratio, the components include:

Short oil alkyd resin 35~50, such as 40, 50;

60% mass concentration titanium dioxide slurry 40~55, such as 45, 48, 52;

Talc powder 5~8, such as 6, 7;

Polyether modified silicone oil leveling agent 0.1~0.5, such as 0.2, 0.3, 0.4;

Fumed silica 0.5~5;

Solvent 1~2.

In a preferred embodiment of the anti-sagging polyurethane white finish paint main paint of the present invention, according to the following weight ratio, the components include:

Short Oil Alkyd 40;

60% mass concentration titanium dioxide slurry 48;

Talc powder 6;

Polyether modified silicone oil leveling agent 0.3;

Fumed silica 0.5~5;

Solvent 1~2.

Among them, the particle size of the talc powder is preferably 2500 mesh to 4500 mesh, more preferably 2800 to 3500 mesh, and most preferably 3000 mesh.

Wherein, the polyether-modified silicone oil is obtained by graft copolymerization of polyether and dialkylsiloxane.

The polyether is selected from any one or any combination of polyethylene oxide or polyethylene glycol, ethylene oxide/propylene oxide copolymer, and polypropylene oxide.

In the dialkylsiloxane, the alkyl group is any one or any combination of C1-C3 alkyls.

The molecular weight of the polyether is preferably 400-6000, preferably 2000-4000.

Wherein, in the polyether-modified silicone oil, the number of dialkylsiloxane linkages is preferably 50-100.

Wherein, the short oil alkyd resin is preferably selected from soybean oil alkyd resin and linseed oil alkyd resin, more preferably soybean oil alkyd resin.

Wherein, the solvent may be any available solvent, preferably toluene, xylene, ethyl acetate, butyl acetate.

In the above-mentioned polyurethane white finish main paint of the present invention, can also comprise auxiliary agent, according to following weight ratio, described anti-sag polyurethane white finish main paint component comprises:

Short oil alkyd resin 35~50, such as 40, 50;

60% mass concentration titanium dioxide slurry 40~55, such as 45, 48, 52;

Talc powder 5~8, such as 6, 7;

Polyether modified silicone oil leveling agent 0.1~0.5, such as 0.2, 0.3, 0.4;

Fumed silica 0.5~5;

Solvent 1~2;

Auxiliary 0.3~1.

Wherein, the auxiliary agents are plasticizers, antioxidants, light stabilizers, defoamers and the like.

The second object of the present invention is to provide a kind of anti-sagging polyurethane white finish paint, described polyurethane white finish paint is two-component polyurethane paint, comprises above-mentioned any kind of main paint, also comprises curing agent, and described curing agent is a One isocyanate prepolymer, or a mixture of multiple isocyanate prepolymers.

In the present invention, isocyanate prepolymer refers to the addition product of isocyanate and polyol (such as dihydric alcohol, trihydric alcohol, tetrahydric alcohol), but it can also be isocyanate multimer (such as dimer, trimer body).

The isocyanate prepolymer can be an aromatic isocyanate prepolymer, an aliphatic isocyanate prepolymer or an alicyclic isocyanate prepolymer, and can be a diisocyanate prepolymer or a polyisocyanate prepolymer, most preferably a diisocyanate prepolymer Polymer, such as the isocyanate prepolymer is selected from toluene diisocyanate prepolymer, diphenylmethane diisocyanate prepolymer, 1,6-hexamethylene diisocyanate prepolymer.

The anti-sagging polyurethane white finish paint provided by the invention has a solid content of 75 wt%, which is obviously higher than that of ordinary PU paints, and reduces pollution caused by solvent volatilization.

The polyurethane white finish paint provided by the present invention has suitable surface tension after the components are combined, and is not easy to sag and bottom out, and even the paint film can change from uneven to flat surface under the action of surface tension.

Detailed ways

The invention provides an anti-sag polyurethane white finish paint, the main paint of the anti-sag polyurethane white finish paint, according to the following weight ratio, the components include:

Short oil alkyd resin 35~50;

60% mass concentration titanium dioxide slurry 40~55;

Talc powder 5~8;

Polyether modified silicone oil leveling agent 0.1~0.5;

Fumed silica 0.5~5;

Solvent 1~2.

The main component of talc powder is talc hydrous magnesium silicate, the molecular formula is Mg ₃ (Si ₄ O ₁₀ )(OH) ₂ . Talc belongs to the monoclinic crystal system, and the crystals are pseudo-hexagonal or rhombohedral flakes, usually in dense massive, leaf-like, radial, and fibrous aggregates, colorless, transparent or white. Talc has excellent physical and chemical properties such as lubricity, fire resistance, acid resistance, insulation, high melting point, chemical inactivity, good hiding power, softness, good gloss, and strong adsorption. It has a slightly larger oil absorption in the product, The present invention uses it as a thixotropic agent, and finds that talcum powder plays a key role in product thixotropy.

The polyether modified silicone oil leveling agent has lower surface tension than the system, and has limited compatibility with the system. It is added in the polyurethane white finish paint of the present invention as a leveling agent, and it is found that the polyether modified silicone oil flows The leveling agent will spontaneously migrate to the surface of the paint film and form a monomolecular film with a fixed and uniform surface tension on the surface. This monomolecular film ensures that the surface tension of the paint film will not change with the change of the paint film (such as curing, Solvent volatilization, etc.), so as to ensure that the paint film can change from uneven to flat surface under the action of surface tension.

The anti-sagging polyurethane white finish paint of the present invention will be described in detail below through specific examples.

Example 1

In the present embodiment, the component of the main paint of anti-sagging polyurethane white finish paint comprises:

Short oil alkyd resin 40kg;

60% mass concentration titanium dioxide slurry 48kg;

Talc powder 6kg;

Polyether modified silicone oil leveling agent 0.3kg;

Fumed silica 0.5kg;

Xylene 1kg;

Defoamer 1kg.

The fineness of talcum powder is 3000 mesh.

Example 2

In the present embodiment, the component of the main paint of anti-sagging polyurethane white finish paint comprises:

Short oil alkyd resin 40kg;

60% mass concentration titanium dioxide slurry 48kg;

Talc powder 6kg;

Polyether modified silicone oil leveling agent 0.3kg;

Fumed silica 2 kg;

Ethyl acetate 2kg;

Antioxidant 0.5kg.

The fineness of talcum powder is 3000 mesh.

Example 3

In the present embodiment, the component of the main paint of anti-sagging polyurethane white finish paint comprises:

Short oil alkyd resin 40kg;

60% mass concentration titanium dioxide slurry 48kg;

Talc powder 6kg;

Polyether modified silicone oil leveling agent 0.3kg;

Fumed silica 5 kg;

Toluene 1.5kg;

Defoamer 0.3kg;

Antioxidant 0.2kg.

The fineness of talcum powder is 3000 mesh.

Example 4

In the present embodiment, the component of the main paint of anti-sagging polyurethane white finish paint comprises:

Short oil alkyd resin 35kg;

60% mass concentration titanium dioxide slurry 42kg;

Talc powder 8kg;

Polyether modified silicone oil leveling agent 0.1kg;

Fumed silica 1 kg;

Butyl acetate 2kg.

The fineness of talcum powder is 3000 mesh.

Example 5

In the present embodiment, the component of the main paint of anti-sagging polyurethane white finish paint comprises:

Short oil alkyd resin 45kg;

60% mass concentration titanium dioxide slurry 55kg;

Talc powder 7kg;

Polyether modified silicone oil leveling agent 0.4kg;

Fumed silica 3 kg;

Ethyl acetate 1.3kg.

The fineness of talcum powder is 3000 mesh.

Comparative example 1

The main paint components of polyurethane white topcoat include:

Short oil alkyd resin 45kg;

60% mass concentration titanium dioxide slurry 55kg;

Colloidal silica 7kg;

Polyacrylate leveling agent 0.4kg;

Fumed silica 3 kg;

Ethyl acetate 1.3kg.

Comparative example 2

The main paint components of polyurethane white topcoat include:

Short oil alkyd resin 45kg;

60% mass concentration titanium dioxide slurry 55kg;

Colloidal silica 20kg;

Polyacrylate leveling agent 0.4kg;

Fumed silica 3 kg;

Ethyl acetate 1.3kg.

The fineness of talcum powder is 3000 mesh. The main paints prepared in the above examples and comparative examples were mixed with isocyanate prepolymers respectively, and coated on a vertical plane. After drying, the flatness and sagging of the paint films were compared.

In the comparative example, when the amount of thixotropic colloidal silica is larger, the sagging phenomenon is reduced, but the coating time is obviously prolonged.

Compared with the comparative example, when the main paint provided in the above-mentioned examples of the present invention is mixed with the isocyanate prepolymer, the sag phenomenon basically disappears, and the coating time is shorter due to the small amount of thixotropic agent added.

In the above-mentioned embodiments of the present invention, the solid content of the anti-sagging polyurethane white top paint can reach about 75wt%, which is significantly higher than that of ordinary PU paints, and the pollution caused by solvent volatilization is reduced.

The specific embodiments of the present invention have been described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, equivalent changes and modifications made without departing from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims (4)

1. a kind of anti-sag polyurethane white topcoat, it is made up of main paint and curing agent, it is characterized in that, described main paint is according to following weight ratio, and component is respectively: Wherein, the short oil alkyd resin is soybean oil alkyd resin; the particle size of the talc powder is 2500 mesh to 4500 mesh; The auxiliary agent is selected from any one or any mixture of plasticizers, antioxidants, light stabilizers and defoamers; The curing agent is an isocyanate prepolymer, or a mixture of multiple isocyanate prepolymers; the isocyanate prepolymer is a diisocyanate prepolymer. 2. anti-sagging polyurethane white finish paint according to claim 1, is characterized in that, described polyether modified silicone oil is obtained by polyether and dialkyl siloxane graft copolymerization; Described polyether is selected from Polyethylene oxide, polypropylene oxide; in the dialkylsiloxane, the alkyl group is any one or any combination of C1-C3 alkyls. 3. anti-sagging polyurethane white finish paint according to claim 1, is characterized in that, described main paint is according to following weight ratio, and component is respectively: 4. anti-sag polyurethane white finish paint according to claim 1, is characterized in that, described isocyanate prepolymer is selected from toluene diisocyanate prepolymer, diphenylmethane diisocyanate prepolymer, 1,6-hexane Diisocyanate prepolymers.