CN113637231B

CN113637231B - Modified calcium carbonate slurry and preparation method thereof, water-based single-component coating for SMC (sheet molding compound) substrate and preparation method and application thereof

Info

Publication number: CN113637231B
Application number: CN202110959150.5A
Authority: CN
Inventors: 余先明
Original assignee: Yastraneng New Material Chongqing Co ltd; ASIA PAINT (SHANGHAI) CO LTD
Current assignee: Yastraneng New Material Chongqing Co ltd; ASIA PAINT (SHANGHAI) CO LTD
Priority date: 2021-08-20
Filing date: 2021-08-20
Publication date: 2023-04-28
Anticipated expiration: 2041-08-20
Also published as: CN113637231A

Abstract

The invention provides modified calcium carbonate slurry and a preparation method thereof, and an aqueous single-component coating for an SMC (sheet molding compound) substrate and a preparation method and application thereof, and relates to the technical field of aqueous coatings, wherein the modified calcium carbonate slurry comprises the following components: 45% -65% of light calcium carbonate, 3% -5% of bentonite and 30% -50% of water, and the water-based single-component paint for the SMC base material comprises the following raw materials: 2-5% of modified calcium carbonate slurry, 45-60% of acrylic acid epoxy hybrid emulsion, 3-10% of polycarbodiimide, 20-40% of pigment and filler and 5-15% of water. The coating provided by the invention is prepared by reacting polycarbodiimide with acrylic epoxy hybrid emulsion, so that the mechanical strength of aqueous resin is improved, and the modified calcium carbonate slurry which is cooperatively dispersed in an aqueous system is further improved in adhesive force with SMC (sheet molding compound) base material, water resistance and chemical resistance, and meanwhile, the coating is quick in drying, easy to construct and wide in application prospect.

Description

Modified calcium carbonate slurry and preparation method thereof, water-based single-component coating for SMC (sheet molding compound) substrate and preparation method and application thereof

Technical Field

The invention relates to the technical field of water-based paint, in particular to modified calcium carbonate slurry, a preparation method thereof, a water-based single-component paint for an SMC (sheet molding compound) substrate, a preparation method and application thereof.

Background

SMC is a composite material, belongs to a kind of glass fiber reinforced plastic, and is mainly made of GF (special yarn), MD (filler) and various auxiliary agents. SMC has the advantages of excellent electrical performance, corrosion resistance, light weight and the like, and the mechanical performance of the SMC is comparable to that of partial metal materials, so that the SMC is widely applied to the industries of electricity, electronics, vehicles, construction, chemical industry, aviation and the like.

However, since a large amount of glass beads are added in the SMC, polishing is not required on a production line, so that the surface of the SMC is smooth, a release agent exists, and how to improve the adhesive force of the paint on the surface of the SMC becomes a pain point of the coating industry.

The traditional SMC is coated by adopting oily double-component polyurethane paint, but with the stricter environmental protection requirements in recent years, the on-line detection of VOC emission is carried out, and the research and development of the water-based paint for the SMC becomes a problem to be solved in the coating field.

Disclosure of Invention

The invention aims to provide modified calcium carbonate slurry for improving the adhesive force of an aqueous coating for SMC, so as to solve the technical problem that the existing coating for SMC is an oily double-component polyurethane coating and cannot meet the environmental protection requirement.

The modified calcium carbonate slurry provided by the invention comprises the following components in percentage by mass: 45% -60% of light calcium carbonate, 3% -5% of bentonite and 30% -50% of water.

Further, the modified calcium carbonate slurry comprises the following components in parts by mass: 50% -60% of light calcium carbonate, 3% -5% of bentonite, 30% -40% of water and 3% -5% of dispersing agent;

the dispersing agent comprises at least one of sodium polyacrylate, sodium orthosilicate, sodium pyrophosphate, sodium hexametaphosphate, sodium polyaluminate, sodium tetraborate, sodium triphosphate or sodium citrate.

Further, the particle sizes of the light calcium carbonate and the bentonite are 1000-2000 meshes;

preferably, the particle size of the light calcium carbonate and the bentonite is 1000-1500 meshes.

The second object of the present invention is to provide a method for preparing the modified calcium carbonate slurry, comprising the steps of: and uniformly mixing the light calcium carbonate, bentonite, water and optional dispersing agent to obtain the modified calcium carbonate slurry.

The invention further aims to provide an aqueous single-component coating for an SMC substrate, which comprises the following raw materials in parts by mass: the invention provides 2% -5% of modified calcium carbonate slurry, 45% -60% of acrylic acid epoxy hybrid emulsion, 3% -10% of polycarbodiimide, 20% -40% of pigment and filler and 5% -15% of water.

Further, the aqueous single-component coating for the SMC substrate comprises the following raw materials in parts by mass: 2-5% of modified calcium carbonate slurry, 50-60% of acrylic acid epoxy hybrid emulsion, 3-7% of polycarbodiimide, 20-40% of pigment and filler, 0.1-7% of auxiliary agent and 5-15% of water.

Further, the pigment and filler comprises at least one of titanium dioxide, barium sulfate or color paste;

preferably, the particle size of the barium sulfate is 1000-1500 meshes;

preferably, the color paste is carbon black color paste.

Further, the auxiliary agent comprises at least one of an antifoaming agent, a thickener, a dispersant, a cosolvent, a wetting agent or a leveling agent.

The fourth object of the present invention is to provide a method for producing the aqueous one-component coating material for SMC base material, comprising the steps of: uniformly mixing the modified nano light calcium carbonate slurry, the acrylic acid epoxy hybrid emulsion, the polycarbodiimide, the pigment filler, the water and the optional auxiliary agent to obtain the water-based single-component coating for the SMC substrate.

The fifth object of the present invention is to provide the use of the aqueous one-component coating for SMC substrates as described above in the automotive, architectural, chemical or aviation fields.

In the modified calcium carbonate slurry provided by the invention, bentonite is dispersed in water to form a clamping structure after swelling, light calcium carbonate particles are adsorbed and anchored, so that stable slurry is formed, the slurry is easy to uniformly disperse in a water-based paint system, and the adhesive force between the water-based paint and an SMC (sheet molding compound) substrate and the gap filling performance of the substrate are enhanced by utilizing the functional groups and the clamping structure of the bentonite, and meanwhile, the mechanical performance, heat resistance, temperature resistance, moisture resistance and surfactant resistance of the water-based paint can be improved.

The aqueous single-component coating for the SMC substrate provided by the invention has the advantages that the mechanical strength of aqueous resin is improved through the reaction of polycarbodiimide and the acrylic epoxy hybrid emulsion, and the adhesive force, the water resistance and the chemical resistance of the modified calcium carbonate slurry which is cooperatively dispersed in an aqueous system are further improved, meanwhile, the drying is fast, the construction is easy, and the application prospect is wide.

Detailed Description

The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

According to one aspect of the invention, the invention provides a modified calcium carbonate slurry, which comprises the following components in percentage by mass: 45% -60% of light calcium carbonate, 3% -5% of bentonite and 30% -50% of water.

In the invention, bentonite is a layered silicate clay mineral which takes montmorillonite as a main component, and the montmorillonite is a small amount of alkali and alkaline earth metal containing aluminosilicate mineral, and the structure of the bentonite is a 2:1 crystal structure formed by two silicon oxygen tetrahedrons which are sandwiched by one layer of aluminum oxygen octahedron.

The precipitated volume of light calcium carbonate (2.4-2.8 mL/g) is greater than the precipitated volume of heavy calcium carbonate (1.1-1.9 mL/g), and is therefore referred to as light calcium carbonate. The relative density of the light calcium carbonate is 2.7-2.9, and the sedimentation volume is more than 2.5 mL/g.

Typically, but not by way of limitation, in the modified calcium carbonate slurry provided by the present invention, the mass fraction of light calcium carbonate is, for example, 45%, 48%, 50%, 52%, 55%, 58% or 60%, the mass fraction of bentonite is, for example, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8% or 5%, and the mass fraction of water is, for example, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48% or 50%.

In a preferred scheme of the invention, in the modified calcium carbonate slurry, the weight fraction of the light calcium carbonate is 50% -60%, the weight fraction of the bentonite is 3% -5%, and the weight fraction of the water is 30% -40%, and when the modified calcium carbonate slurry further contains the dispersing agent with the weight fraction of 3% -5%, the light calcium carbonate particles are more favorably and uniformly anchored in a clamping house structure formed by the bentonite, so that the performance of the formed modified calcium carbonate slurry is more stable and uniform.

Typically, but not by way of limitation, the dispersing agent is selected from one or more of sodium polyacrylate, sodium orthosilicate, sodium pyrophosphate, sodium hexametaphosphate, sodium polyaluminate, sodium tetraborate, sodium triphosphate, or sodium citrate.

Preferably, the particle size of the bentonite is 1000-2000 meshes so as to be favorable for uniform dispersion of the bentonite in water and form a plurality of uniformly dispersed clamping structures after water absorption and swelling, and particularly, when the particle size of the bentonite is 1000-1500 meshes, the bentonite is more favorable for dispersion in water to form the clamping structures.

Typically, but not by way of limitation, the bentonite has a particle size of 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 or 2000 mesh.

Preferably, the particle size of the light calcium carbonate is 1000-2000 meshes, so that the light calcium carbonate particles are uniformly dispersed, adsorbed and anchored in a clamping house structure formed after the bentonite swells in water, the stability of slurry is enhanced, and particularly when the particle size of the light calcium carbonate is 1000-1500 meshes, the light calcium carbonate particles are more uniformly dispersed, adsorbed and anchored in the clamping house structure formed after the bentonite swells in water.

Typically, but not by way of limitation, the particle size of the light calcium carbonate is, for example, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 or 2000 mesh.

Preferably, the water is deionized water to avoid impurities in the water affecting the stability and uniformity of slurry dispersion.

According to a second aspect of the present invention, there is provided a process for the preparation of the above-described modified calcium carbonate slurry, according to the following steps: and uniformly mixing the light calcium carbonate, bentonite, water and optional dispersing agent to obtain the modified calcium carbonate slurry.

In a preferred embodiment of the invention, the modified calcium carbonate slurry is prepared by the steps of:

the deionized water, the dispersing agent and 1250-mesh light calcium carbonate are dispersed at a high speed for 30min to ensure that the fineness is 30 microns, then bentonite with the particle size of 1000-1500 meshes is added, the bentonite is dispersed at a high speed to fully swell to form a clamping structure, the dispersed light calcium carbonate particles are adsorbed and anchored, and the mixture is stood for 10min to form uniform and stable slurry.

According to a third aspect of the invention, the invention provides an aqueous one-component coating for SMC (sheet molding compound) substrates, which comprises the following raw materials in percentage by mass: the modified calcium carbonate slurry provided by the first aspect of the invention is 2% -5%, the acrylic acid epoxy hybrid emulsion is 45% -60%, the polycarbodiimide is 3% -10%, the pigment filler is 20% -40% and the water is 5% -15%.

In the present invention, the acrylic epoxy hybrid emulsion has a mass fraction of 50% -55%, a pH of 8.5-9.5, and a minimum film forming temperature of 15+ -2deg.C, which is commercially available, including but not limited to Dow.

The polycarbodiimide is used for reacting with carboxyl in the acrylic epoxy hybrid emulsion to improve the paint film strength of the paint.

The addition of pigment and filler is advantageous on the one hand for reducing the cost of the coating and on the other hand for improving the colour and luster as well as the mechanical properties of the coating.

In the aqueous single-component coating for the SMC substrate, the mass fraction of the modified calcium carbonate slurry is 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5% or 5%; the mass fraction of the acrylic epoxy hybrid emulsion is 45%, 48%, 50%, 52%, 55%, 58% or 60%, and the mass fraction of the polycarbodiimide is 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 8.5%, 9%, 9.5% or 10%; the mass fraction of the pigment and filler is, for example, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38% or 40%; the mass fraction of water is, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%.

In addition, the water-based single-component coating for the SMC substrate has excellent antirust performance, the construction time can reach more than 5 hours, and the water-based single-component coating is environment-friendly and is a nontoxic pollution-free environment-friendly water-based product.

In a preferred embodiment of the invention, the pigment and filler comprises one or more of titanium dioxide, barium sulfate or color paste.

Titanium dioxide is a dye and pigment, and has the characteristics of good weather resistance, water resistance and difficult yellowing.

Barium sulfate is white amorphous powder, has stable property and is insoluble in water, acid, alkali or organic solvent.

Preferably, the barium sulfate is ultrafine barium sulfate with a particle size of 1000-1500 mesh to facilitate uniform dispersion in the coating.

Preferably, the color paste is carbon black color paste, so that the prepared water-based single-component coating for the SMC substrate is used as a primer.

In a preferred scheme of the invention, the water-based single-component paint for the SMC substrate contains titanium dioxide, barium sulfate and carbon black color paste, wherein the mass fraction of the titanium dioxide is 15-22%, the mass fraction of the barium sulfate is 8-15%, and the mass fraction of the carbon black color paste is 0.7-1%, so that the prepared SMC substrate has excellent adhesive property and mechanical property and is lower in cost.

Typically, without limitation, the mass fraction of titanium dioxide in the aqueous one-component fat coating for SMC substrates is, for example, 15%, 16%, 17%, 18%, 19%, 20%, 21% or 22%; the mass fraction of the barium sulfate is 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%; the mass fraction of the carbon black color paste is 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%.

In a preferred embodiment of the invention, an adjuvant is also included in the aqueous one-component coating for SMC substrates to further improve the overall properties of the aqueous one-component coating for SMC substrates.

Preferably, the aqueous single-component coating for the SMC substrate comprises the following raw materials in mass percent: when 2% -5% of modified calcium carbonate slurry, 50% -60% of acrylic acid epoxy hybrid emulsion, 3% -7% of polycarbodiimide, 20% -40% of pigment and filler, 0.1% -7% of auxiliary agent and 5% -15% of water, the prepared water-based single-component coating for the SMC substrate has stronger adhesive force on the surface of the SMC substrate and better water resistance and chemical resistance.

Preferably, the auxiliary agent comprises one or more of an antifoaming agent, a thickener, a dispersant, a cosolvent, a wetting agent or a leveling agent.

Preferably, the defoamer is a hydrophobically modified silicone-based defoamer, such as BYK-024.

Preferably, the dispersant is an anionic dispersant, such as BYK-154/181.

Preferably, the thickener is a polyurethane thickener, commercially available.

Preferably, the cosolvent is DPNB (dipropylene glycol butyl ether).

Preferably, the wetting agent is an anionic dispersant, such as BYK-346.

Preferably, the leveling agent is TEGO 450.

In a preferred embodiment of the invention, the aqueous one-component coating for SMC substrates comprises the following auxiliaries in mass fraction: 0.1 to 0.3 percent of defoaming agent, 0.3 to 0.6 percent of dispersing agent, 2 to 5 percent of cosolvent, 0.1 to 0.5 percent of wetting agent and 0.2 to 1 percent of thickening agent.

Typically, but not by way of limitation, in aqueous one-component coatings for SMC substrates, the defoamer is, for example, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%; the mass fraction of the dispersant is, for example, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55% or 0.6%; the mass fraction of the cosolvent is, for example, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%; the mass fraction of the wetting agent is, for example, 0.1%, 0.2%, 0.3%, 0.4% or 0.5%; the mass fraction of the thickener is, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%.

According to a fourth aspect of the present invention, the present invention provides a method for preparing the aqueous one-component coating for SMC substrates, which comprises the following steps: and uniformly mixing the modified calcium carbonate slurry, the acrylic acid epoxy hybrid emulsion, the polycarbodiimide, the pigment filler, water and optional auxiliary agents to obtain the water-based single-component coating for the SMC substrate.

The preparation method of the water-based paint for the SMC substrate provided by the invention has the advantages of simple process, easiness in operation, safety, environmental friendliness and easiness in large-scale production.

According to a fifth aspect of the present invention there is provided the use of an aqueous one-component coating for SMC substrates as described above in the automotive, architectural, chemical or aeronautical field.

The technical solutions provided by the present invention will be further described below in connection with examples and comparative examples for the convenience of understanding of those skilled in the art.

The manufacturers and models of the raw materials used in examples and comparative examples are shown in Table 1 below, and raw materials not specified in the tables are commercially available.

TABLE 1

Raw material name	Manufacturer model
		Defoaming agent	BYK-024
Dispersing agent	BYK-154/181
		Light calcium carbonate	1250 mesh
Bentonite clay	1500 mesh
		Titanium white powder	Rutile type
Barium sulfate	1250 mesh
		Acrylic epoxy hybrid emulsion	AEH-20 of Dow
Cosolvent	DPNB
		Wetting agent	BYK-346
Leveling agent	TEGO 450
		Carbon black color paste	SG2270
Thickening agent	Polyurethane

Example 1

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 3 parts of modified calcium carbonate slurry, 52 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 10 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersant, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener.

The modified calcium carbonate slurry is prepared according to the following steps: the deionized water, sodium hexametaphosphate and 1250-mesh light calcium carbonate are dispersed at a high speed for 30 minutes until the fineness is 30 microns, bentonite is added, the bentonite is dispersed at a high speed, the bentonite is fully swelled to form a clamping structure, dispersed light calcium carbonate particles are adsorbed to form an anchor, and the anchor is placed for 10 minutes, so that uniform and stable modified calcium carbonate slurry is formed, wherein the deionized water is 35 parts by mass, the 1250-mesh light calcium carbonate is 55 parts by mass, the bentonite is 5 parts by mass, and the sodium hexametaphosphate is 5 parts by mass.

Example 2

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 3.5 parts of modified calcium carbonate slurry, 52 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 9.5 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersant, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of flatting agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Example 3

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 4 parts of modified calcium carbonate slurry, 52 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 9 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersing agent, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Example 4

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 5 parts of modified calcium carbonate slurry, 50 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 17 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 9 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersing agent, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Example 5

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 2 parts of modified calcium carbonate slurry, 60 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 10 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 9 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersing agent, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Example 6

The embodiment provides an aqueous single-component coating for an SMC (sheet molding compound) substrate, which comprises the following raw materials in parts by weight: 5 parts of modified calcium carbonate slurry, 45 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 12 parts of 1250-mesh barium sulfate, 13 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersant, 2 parts of cosolvent barium, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Example 7

The present embodiment provides an aqueous single-component coating for SMC substrate, which is different from embodiment 1 in that the mass ratio of the raw materials of the modified calcium carbonate slurry is different from embodiment 1, in this embodiment, the raw materials of the modified calcium carbonate slurry are 30 parts by mass of deionized water, 60 parts by mass of 1250-mesh light calcium carbonate, 5 parts by mass of bentonite, 5 parts by mass of sodium hexametaphosphate, and the preparation method of the modified calcium carbonate slurry is the same as embodiment 1, and is not described herein.

Example 8

The present embodiment provides an aqueous single-component coating for SMC substrate, which is different from embodiment 1 in that the mass ratio of the raw materials for preparing the modified calcium carbonate slurry is different from embodiment 1, in this embodiment, the raw materials for preparing the modified calcium carbonate slurry are 40 parts by mass of deionized water, 50 parts by mass of 1250-mesh light calcium carbonate, 5 parts by mass of bentonite, and 5 parts by mass of sodium hexametaphosphate, and the preparation method of the modified calcium carbonate slurry is the same as embodiment 1, and is not described herein.

Example 9

The present embodiment provides an aqueous single-component coating for SMC substrate, which is different from embodiment 1 in that the mass ratio of the raw materials for preparing the modified calcium carbonate slurry is different from embodiment 1, in this embodiment, the raw materials for preparing the modified calcium carbonate slurry are 38 parts by mass of deionized water, 55 parts by mass of 1250-mesh light calcium carbonate, 4 parts by mass of bentonite, 3 parts by mass of sodium hexametaphosphate, and the preparation method of the modified calcium carbonate slurry is the same as embodiment 1, and is not described herein.

The aqueous one-component coating for SMC substrates provided in examples 1-9 above was prepared as follows: and uniformly mixing the modified calcium carbonate slurry, the acrylic acid epoxy hybrid emulsion, the polycarbodiimide, the titanium pigment, the barium sulfate, the defoamer, the dispersing agent, the cosolvent, the wetting agent, the flatting agent, the thickener, the carbon black color paste and water to obtain the water-based single-component coating for the SMC substrate.

Comparative example 1

The comparative example provides a water-based paint which comprises the following raw materials in parts by mass: 52 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 13 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersant, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of flatting agent, 0.8 part of carbon black color paste and 1 part of thickener.

Comparative example 2

The comparative example provides a water-based paint which comprises the following raw materials in parts by mass: 1 part of modified calcium carbonate slurry, 52 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 12 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersing agent, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Comparative example 3

The comparative example provides a water-based paint which comprises the following raw materials in parts by mass: 10 parts of modified calcium carbonate slurry, 40 parts of acrylic acid epoxy hybrid emulsion, 4 parts of polycarbodiimide, 16 parts of titanium dioxide, 10 parts of 1250-mesh barium sulfate, 10 parts of deionized water, 0.1 part of defoamer, 0.5 part of dispersing agent, 2 parts of cosolvent, 0.3 part of wetting agent, 0.2 part of leveling agent, 0.8 part of carbon black color paste and 1 part of thickener, wherein the modified calcium carbonate slurry and the modified calcium carbonate slurry adopted in the embodiment 1 are in the same batch.

Comparative example 4

This comparative example provides an aqueous coating material which differs from example 1 in that a modified calcium carbonate slurry is used which is different in composition and which is made from the following raw materials in parts by mass: 60 parts of light calcium carbonate, 1 part of bentonite, 5 parts of sodium hexametaphosphate and 34 parts of water, and the preparation method of the modified calcium carbonate slurry is the same as that of example 1, and is not repeated here.

Comparative example 5

This comparative example provides an aqueous coating material which differs from example 1 in that a modified calcium carbonate slurry is used which is different in composition and which is made from the following raw materials in parts by mass: 50 parts of light calcium carbonate, 10 parts of bentonite, 5 parts of sodium hexametaphosphate and 35 parts of water, and the preparation method of the modified calcium carbonate slurry is the same as that of example 1, and is not repeated here.

The preparation method of the water-based paint provided in comparative examples 1 to 5 is carried out according to the following steps:

uniformly mixing the acrylic acid epoxy hybrid emulsion, polycarbodiimide, titanium dioxide, barium sulfate, a defoaming agent, a dispersing agent, a cosolvent, a wetting agent, a leveling agent, a thickening agent, carbon black color paste, water and optional modified calcium carbonate slurry to obtain the water-based monocomponent coating for the SMC substrate.

Test example 1

The state of the aqueous paints provided in examples 1 to 9 and comparative examples 1 to 5 in the container, paint film color and appearance, hardness, adhesion, heat resistance, temperature resistance, moisture resistance and surfactant resistance were measured, and the technical indexes of the respective test items and the test results according to the following table 2 are shown in tables 3 and 4.

TABLE 2

TABLE 3 Table 3

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TABLE 4 Table 4

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. The modified calcium carbonate slurry is characterized by comprising the following components in percentage by mass: 50% -60% of light calcium carbonate, 3% -5% of bentonite, 30% -40% of water and 3% -5% of dispersing agent;

the dispersing agent comprises at least one of sodium polyacrylate, sodium orthosilicate, sodium pyrophosphate, sodium hexametaphosphate, sodium polyaluminate, sodium tetraborate, sodium triphosphate or sodium citrate;

the particle sizes of the light calcium carbonate and the bentonite are 1000-1500 meshes.

2. The method for preparing a modified calcium carbonate slurry according to claim 1, wherein the method comprises the steps of: and uniformly mixing the light calcium carbonate, bentonite, water and optional dispersing agent to obtain the modified calcium carbonate slurry.

3. The water-based single-component coating for the SMC substrate is characterized by comprising the following raw materials in parts by mass: 2-5% of the modified calcium carbonate slurry of claim 1, 45-60% of the acrylic epoxy hybrid emulsion, 3-10% of the polycarbodiimide, 20-40% of the pigment and filler and 5-15% of the water.

4. An aqueous one-component coating for SMC substrates according to claim 3, characterized in that it comprises the following raw materials, in mass: 2-5% of the modified calcium carbonate slurry of claim 1, 50-60% of acrylic epoxy hybrid emulsion, 3-7% of polycarbodiimide, 20-40% of pigment and filler, 0.1-7% of auxiliary agent and 5-15% of water.

5. An aqueous one-component coating for SMC substrates according to claim 3, characterized in that said pigment filler comprises at least one of titanium white, barium sulphate or colour paste;

the particle size of the barium sulfate is 1000-1500 meshes;

the color paste is carbon black color paste.

6. The aqueous one-component coating for SMC substrates according to claim 4, characterized in that said auxiliary agent comprises at least one of defoamers, thickeners, dispersants, co-solvents, wetting agents or leveling agents.

7. A process for the preparation of an aqueous one-component coating for SMC substrates according to any of the claims 3-6, characterized by the following steps: and uniformly mixing the modified calcium carbonate slurry, the acrylic acid epoxy hybrid emulsion, the polycarbodiimide, the pigment filler, water and optional auxiliary agents to obtain the water-based single-component coating for the SMC substrate.

8. Use of an aqueous one-component coating for SMC substrates according to any of the claims 3 to 6 in the automotive, architectural, chemical or aeronautical field.