CN113150649A - Water-based anti-bleeding ultralow-VOC high-fullness white primer and preparation method thereof - Google Patents

Abstract

The invention discloses a water-based anti-bleeding ultra-low VOC high-fullness white primer and a preparation method thereof, wherein the primer comprises a main paint and a curing agent, and the main paint comprises the following components in percentage by mass: 30-45% of liquid epoxy resin, 0.4-0.8% of dispersing agent, 18-25% of titanium dioxide, 0.5-1% of anti-settling agent, 0.2-0.4% of defoaming agent, 0.2-0.4% of wetting and leveling agent, 20-35% of filler, 5-8% of active diluent and 2-5% of cosolvent; the mass ratio of the main paint to the curing agent is 1: 0.25. The white primer disclosed by the invention has very high crosslinking density, forms a compact and smooth protective coating on the surface of a base material, has obviously better coating hardness and fullness than those of conventional water-based white primers, has excellent sinking resistance, can effectively seal tannic acid or pigment in the base material, prevents the tannic acid or pigment from upwards permeating, can completely solve the problem of white coating discoloration without spraying the seal primer, improves the coating effect of white furniture, obviously reduces VOC (volatile organic compounds) emission in the coating process, and conforms to the policy guidelines of energy conservation and emission reduction.

Description

Water-based anti-bleeding ultralow-VOC high-fullness white primer and preparation method thereof

Technical Field

The invention relates to the technical field of paint, in particular to a water-based anti-bleeding ultra-low VOC high-fullness white primer and a preparation method thereof.

Background

The white coated furniture is pure and elegant, makes brief, vivid and vivid modern fashion and breath, improves the value feeling of the furniture, and is particularly popular in the market and loved by customers by adopting a green and environment-friendly water-based wood coating. However, in the white coating process of the water-based wood coating, the compactness of the coating is poor, the sealing effect is poor, hydrophilic colored substances or tannic acid contained in wood can be dissolved in water and then can slowly diffuse and seep to migrate to the surface of the coating along with the drying of the coating, so that the color change and the flowering of white finish are caused, the furniture coating effect is greatly influenced, furniture enterprises are forced to adopt a matched process of firstly preparing a sealing primer to prevent the white paint of the subsequent process from changing color, the coating times are increased, the construction is complicated, the coating cost is high, the tannic acid or the colored substances of a substrate with heavier color and luster can not be completely sealed, the requirements of users on high coating efficiency and high effect quality can not be met, the problem which always puzzles the coating industry is one, and the development of the water-based wood coating is also hindered to a great extent. In view of the above disadvantages, there is an urgent need to develop a white primer for waterborne woodware, which can prevent bleeding and has high coating efficiency without matching with a sealing primer, and can meet the requirement of customers on long-term effect of preventing bleeding of various substrates.

Disclosure of Invention

The invention aims to provide a water-based anti-bleeding ultra-low VOC high-fullness white primer and a preparation method thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

the water-based anti-bleeding ultra-low VOC high-fullness white primer comprises a main paint and a curing agent, wherein the main paint comprises the following components in percentage by mass: 30-45% of liquid epoxy resin, 0.4-0.8% of dispersing agent, 18-25% of titanium dioxide, 0.5-1% of anti-settling agent, 0.2-0.4% of defoaming agent, 0.2-0.4% of wetting and leveling agent, 20-35% of filler, 5-8% of active diluent and 2-5% of cosolvent; the mass ratio of the main paint to the curing agent is 1: 0.25.

Furthermore, the white primer takes water as a diluent, and the mass ratio of the main paint to the curing agent to the water is 1: 0.25: 0.5-1 after the water is added.

Furthermore, the liquid epoxy resin is DER331 of DOW company DE, the epoxy equivalent is 182-.

Furthermore, the dispersing agent is a high molecular weight block copolymer dispersing agent containing pigment affinity groups, so that the dispersing time of titanium dioxide and filler in an epoxy coating system can be obviously shortened, the titanium dioxide and the filler are ensured to be stable in the system for a long time, flocculation and sedimentation are prevented, the tinting strength and luster are increased, the viscosity of the system is reduced, and the leveling of a coating film after construction is promoted.

Furthermore, the titanium dioxide is rutile titanium dioxide, and provides good whiteness and covering power for a coating film. The anti-settling agent is fumed silica, a hydrogen bond network structure with thixotropy is formed in a system, an excellent anti-settling effect is obtained, the construction performance of the coating is improved, good leveling property and sagging resistance are provided, and thick coating film forming can be realized.

Furthermore, the reactive diluent is a hydrophilic reactive diluent C12-C14 alkyl glycidyl ether, so that the viscosity of the system is reduced, the emulsion liquid epoxy resin is assisted to enable the coating system to be more stable, the fluidity is improved, the wetting of the primer to the basal plane of the substrate and the permeation into the substrate are improved, the air in the substrate is quickly replaced, the foaming is avoided, the flexibility of the system can be greatly improved, the cracking of a thick coating film is prevented, meanwhile, an epoxy group is carried by the primer to participate in the crosslinking curing reaction, the fullness and compactness of the coating film are further improved, the permeation resistance is improved, and particularly, the VOC of the system can be reduced.

Furthermore, the defoaming agent is a polyether modified polysiloxane defoaming agent, is a special foam breaking polysiloxane liquid defoaming agent for an epoxy coating system, can quickly and effectively eliminate bubbles in a thick coating film, and ensures the compactness of the coating film. The flatting agent is fluorine modified polyacrylic acid flatting agent, effectively promotes the primer to wet the substrate fast, and the adsorbed gas molecule of discharge substrate can provide certain defoaming and defoaming ability, has fabulous anti-shrinkage cavity ability and leveling nature, and the defoaming agent that the cooperation was chooseed for use has both can the production of suppression bubble, can eliminate the bubble that has generated again, satisfies the not foamy requirement of thick coating completely, obtains level and smooth coating.

Furthermore, the fillers are precipitated barium sulfate, mica powder and zinc stearate, wherein the precipitated barium sulfate has small oil absorption, overcomes the pseudo-thickening tendency and viscosity increase problems of the traditional inorganic filler, improves the leveling property of the coating, ensures the flatness and fullness of the coating, improves the compactness and strength of the coating, prevents collapse, and improves the coating effect of the white finish paint in the next process. The zinc stearate effectively improves the sanding property of the coating.

Furthermore, the cosolvent is formed by mixing propylene glycol methyl ether and ethanol according to the mass ratio of 4:6, so that emulsification and film forming are facilitated, wherein the propylene glycol methyl ether has small pollution to the environment and high safety, the ethanol belongs to a reproducible nontoxic solvent, and a solvent system has low toxicity and cannot pollute the environment.

Furthermore, the curing agent is self-emulsified modified polyamide, the amine value is 180-220mgKOH/g, the solid content is 100%, the curing agent has the functions of emulsifying and curing epoxy resin, has good water dispersibility, has good emulsification effect on the epoxy resin to form a stable emulsion system, and has high crosslinking density of a cured coating, compact coating, excellent bleeding resistance and longer pot life, particularly, the curing agent contains longer flexible molecular chains, so that the coating has good flexibility and cracking resistance.

The invention provides another technical scheme: a preparation method of a water-based anti-bleeding ultra-low VOC high-fullness white primer comprises the following steps:

s1: preparation of the Main Lacquer

a. Weighing the following raw materials by mass percent, 30-45% of liquid epoxy resin, 0.4-0.8% of dispersing agent, 18-25% of titanium dioxide, 0.5-1% of anti-settling agent, 0.2-0.4% of defoaming agent, 0.2-0.4% of wetting and leveling agent, 20-35% of filler, 5-8% of active diluent and 2-5% of cosolvent;

b. adding liquid epoxy resin, active diluent and part of cosolvent into a container, and dispersing for 5 minutes at the speed of 600-800 rpm; then dispersing while adding a dispersing agent, an anti-settling agent, titanium dioxide and a filler at the speed of 600-800 r/min, and dispersing for 40 minutes at the speed of 1200-1500 r/min until the fineness is less than 50 um;

c. adding the rest cosolvent and the auxiliary agent, and dispersing for 10 minutes at the speed of 600 plus 800 rpm to obtain a main paint component;

s2: the paint comprises the following main paint in percentage by mass: curing agent 1: 0.25, uniformly mixing the main paint and the curing agent, adding water as a diluent, and mixing the main paint and the curing agent according to the mass ratio: curing agent: water 1: 0.25: uniformly mixing the components in a ratio of 0.5-1; spraying or brushing on the surface of the woodware, and naturally drying or baking and drying at low temperature.

Compared with the prior art, the invention has the beneficial effects that:

1. the modified polyamide curing agent selected by the water-based anti-bleeding ultra-low VOC high-fullness white primer prepared by the invention is not only a cross-linking agent but also an emulsifying agent, has good compatibility with liquid epoxy resin, can form a stable coating system with small latex particle size, narrow distribution range and good permeability, has excellent construction performance, latex particles can easily permeate into a fiber duct of wood to be cured into a macromolecular reticular structure, has very high cross-linking density, ensures that a coating film is compact and firm, has high hardness, good permeability resistance and sink resistance, particularly contains strong-polarity ether bonds and hydroxyl groups in the molecular structure of the epoxy resin, forms hydrogen bonds with the hydroxyl groups in wood fibers by the amino groups of the functional groups, has excellent adhesive force to wood, can completely seal tannic acid or pigment in the wood, and can react with the tannic acid in the wood to form stable chelate so that the coating layer is fixed on an interface, further achieves the aim of sealing the tannic acid, effectively prevents the tannic acid and the hydrophilic pigment in the wood from exuding, obviously improves the anti-bleeding performance of the coating, and effectively eliminates the color change phenomenon after the coating is dried. Particularly, the mica powder with a sheet structure is adopted, a parallel, overlapped and oriented arrangement structure is presented in the coating film, a sheet-shaped shielding layer is formed, micropores in the coating film are cut off, a labyrinth effect is formed, the migration path of water-soluble substances from a substrate to the surface of the coating film is prolonged, other fillers can fill gaps among the mica powder sheets, the compactness of the coating is enhanced, the anti-bleeding performance of the coating film is further enhanced, and long-acting protection on finish paint is finally realized through optimization of all components.

2. The white primer can be constructed on different substrates, can be directly constructed without coating a sealing primer, thoroughly solves the problem of color change of a white coating, obviously saves construction procedures and reduces the labor cost of coating.

3. The white primer has no by-product of gas in the curing reaction process, thereby thoroughly solving the problems of easy generation of dark bubbles and miliaria in the thick coating process of the double-component white primer, so that the coating can be applied thickly, the coating times are reduced, the coating efficiency is improved, and the VOC emission is obviously reduced.

4. The white primer system does not adopt an emulsifier, eliminates the influence of the emulsifier on a coating film, thoroughly solves the problem of water sensitivity of the conventional water-based paint, obviously improves the defoaming performance of the system, ensures the compactness of the coating film, has excellent water resistance and adhesive force, and further prevents the bleeding phenomenon caused by the permeation of water in the water-based paint for subsequent construction through the coating film.

5. The white primer exists in a solvent type coating state, has good preparation process operability, simple production method, no need of special equipment, no wastewater discharge in the production process, waste discharge treatment cost saving, suitability for large-scale production, no problems of poor freezing-thawing stability and storage stability of the conventional water-based coating, and excellent storage stability.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Preparing main paint; weighing 100kg of the following components in percentage by mass: 32kg of liquid epoxy resin, 0.8kg of dispersing agent, 20kg of titanium dioxide, 1kg of anti-settling agent, 0.2kg of defoaming agent, 0.2kg of wetting and leveling agent, 35kg of filler, 6kg of active diluent and 4.8kg of cosolvent; adding liquid epoxy resin, active diluent and part of cosolvent into a container, and dispersing for 5 minutes at the speed of 600-800 rpm; then dispersing while adding a dispersing agent, an anti-settling agent, titanium dioxide and a filler at the speed of 600-800 r/min, and dispersing for 40 minutes at the speed of 1200-1500 r/min until the fineness is less than 50 um; adding the rest cosolvent and the auxiliary agent, and dispersing for 10 minutes at the speed of 600-800 rpm to obtain the main paint component.

Coating; fully stirring and uniformly mixing the main paint and the curing agent, then adding water, and mixing according to the mass ratio of the main paint, the curing agent and the water of 1: 0.25: 0.5-1; after being mixed evenly, the mixture is sprayed or brushed on the surface of woodware, and the woodware is naturally dried or baked and dried at low temperature, and the construction effective period is 4 hours.

Example 2

Preparing main paint; weighing 100kg of the following components in percentage by mass: 38kg of liquid epoxy resin, 0.5kg of dispersing agent, 22kg of titanium dioxide, 0.8kg of anti-settling agent, 0.3kg of defoaming agent, 0.3kg of wetting and leveling agent, 28kg of filler, 6kg of active diluent and 4.1kg of cosolvent; adding liquid epoxy resin, active diluent and part of cosolvent into a container, and dispersing for 5 minutes at the speed of 600-800 rpm; then dispersing while adding a dispersing agent, an anti-settling agent, titanium dioxide and a filler at the speed of 600-800 r/min, and dispersing for 40 minutes at the speed of 1200-1500 r/min until the fineness is less than 50 um; adding the rest cosolvent and the auxiliary agent, and dispersing for 10 minutes at the speed of 600-800 rpm to obtain the main paint component.

Coating; fully stirring and uniformly mixing the main paint and the curing agent, and then adding water, wherein the main paint, the curing agent and the water are mixed according to the mass ratio of 1: 0.25: 0.5-1; after being mixed evenly, the mixture is sprayed or brushed on the surface of woodware, and the woodware is naturally dried or baked and dried at low temperature, and the construction effective period is 4 hours.

Example 3

Preparing main paint; weighing 100kg of the following components in percentage by mass: 45kg of liquid epoxy resin, 0.6kg of dispersing agent, 25kg of titanium dioxide, 0.5kg of anti-settling agent, 0.3kg of defoaming agent, 0.4kg of wetting and leveling agent, 20kg of filler, 6kg of active diluent and 2.2kg of cosolvent; adding liquid epoxy resin, active diluent and part of cosolvent into a container, and dispersing for 5 minutes at the speed of 600-800 rpm; then dispersing while adding a dispersing agent, an anti-settling agent, titanium dioxide and a filler at the speed of 600-800 r/min, and dispersing for 40 minutes at the speed of 1200-1500 r/min until the fineness is less than 50 um; adding the rest cosolvent and the auxiliary agent, and dispersing for 10 minutes at the speed of 600-800 rpm to obtain the main paint component.

Coating; fully stirring and uniformly mixing the main paint and the curing agent, and then adding water, wherein the main paint, the curing agent and the water are mixed according to the mass ratio of 1: 0.25: 0.5-1; after being mixed evenly, the mixture is sprayed or brushed on the surface of woodware, and the woodware is naturally dried or baked and dried at low temperature, and the construction effective period is 4 hours.

The water-based anti-bleeding ultra-low VOC high-fullness white primer disclosed by the invention, and a water-based two-component polyurethane white primer and a solvent type polyurethane white primer which are purchased from the market are directly coated on the red oak at the same time, and then the performances are compared, as shown in the following table:

as can be seen from the data in the table above: the performance of the water-based anti-bleeding ultralow-VOC high-fullness white primer prepared by the invention is obviously better than that of the water-based two-component polyurethane white primer and the solvent-based polyurethane white primer on the market, the primer can be thickly coated into a film, the sinking resistance is good, the problem of poor sealing performance of the water-based white primer is solved, tannic acid and pigment in a base material can be prevented from bleeding upwards, the long-acting anti-bleeding effect is achieved, meanwhile, the ultralow-VOC paint has ultralow VOC, the VOC emission in the coating process is obviously reduced, the paint belongs to a green environment-friendly paint, a very good environment-friendly solution is provided for furniture enterprises, the production requirements of the furniture enterprises on energy conservation, environmental protection and high efficiency are met, and the government environment-friendly policy is met.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.

Claims (9)

1. The water-based anti-bleeding ultra-low VOC high-fullness white primer comprises a main paint and a curing agent, and is characterized in that the main paint comprises the following components in percentage by mass: 30-45% of liquid epoxy resin, 0.4-0.8% of dispersing agent, 18-25% of titanium dioxide, 0.5-1% of anti-settling agent, 0.2-0.4% of defoaming agent, 0.2-0.4% of wetting and leveling agent, 20-35% of filler, 5-8% of active diluent and 2-5% of cosolvent; the mass ratio of the main paint to the curing agent is 1: 0.25.

2. The water-based anti-bleeding ultra-low VOC high-fullness white primer as claimed in claim 1, wherein the white primer uses water as a diluent, and the mass ratio of the components after the water is added is 1: 0.25: 0.5-1.

3. The waterborne bleed-resistant ultra-low VOC high fullness white primer of claim 1 wherein the liquid epoxy resin is DER331, epoxy equivalent 182-.

4. The aqueous bleeding-preventing ultra-low VOC high-fullness white primer as claimed in claim 1, wherein said dispersant is a high molecular weight block copolymer dispersant containing pigment affinity groups, said defoamer is a polyether modified polysiloxane defoamer, and said wetting leveling agent is a fluorine modified polyacrylic leveling agent.

5. The aqueous bleed-resistant ultra-low VOC high-fullness white primer of claim 1, wherein the titanium dioxide is rutile titanium dioxide, the anti-settling agent is fumed silica, and the filler is precipitated barium sulfate, mica powder and zinc stearate.

6. The waterborne bleed-resistant ultra-low VOC high-fullness white primer of claim 1, wherein the reactive diluent is a hydrophilic reactive diluent C12-C14 alkyl glycidyl ether.

7. The waterborne bleed-proof ultralow VOC high-fullness white primer of claim 1, wherein the cosolvent is propylene glycol methyl ether and ethanol mixed at a mass ratio of 4: 6.

8. The waterborne bleed-resistant ultra-low VOC high-fullness white primer of claim 1, wherein the curing agent is a self-emulsifying modified polyamide with an amine value of 180-220mgKOH/g and a solids content of 100%.

9. A method of preparing the waterborne bleed-resistant ultra-low VOC high-fullness white primer of claim 1, comprising the steps of:

s1: preparation of the Main Lacquer

a. Weighing the following raw materials by mass percent, 30-45% of liquid epoxy resin, 0.4-0.8% of dispersing agent, 18-25% of titanium dioxide, 0.5-1% of anti-settling agent, 0.2-0.4% of defoaming agent, 0.2-0.4% of wetting and leveling agent, 20-35% of filler, 5-8% of active diluent and 2-5% of cosolvent;

b. adding liquid epoxy resin, active diluent and part of cosolvent into a container, and dispersing for 5 minutes at the speed of 600-800 rpm; then dispersing while adding a dispersing agent, an anti-settling agent, titanium dioxide and a filler at the speed of 600-800 r/min, and dispersing for 40 minutes at the speed of 1200-1500 r/min until the fineness is less than 50 um;

c. adding the rest cosolvent and the auxiliary agent, and dispersing for 10 minutes at the speed of 600 plus 800 rpm to obtain a main paint component;

s2: the paint comprises the following main paint in percentage by mass: curing agent 1: 0.25, uniformly mixing the main paint and the curing agent, adding water as a diluent, and mixing the main paint and the curing agent according to the mass ratio: curing agent: water 1: 0.25: uniformly mixing the components in a ratio of 0.5-1; spraying or brushing on the surface of the woodware, and naturally drying or baking and drying at low temperature.