Fire-retardant water-based primer for wood flooring and method for preparing the same

Abstract

The application discloses a kind of fire-retardant water-based primer for wood floor and preparation method thereof, belong to water-based wood coating technical field, the fire-retardant water-based primer includes the following weight parts components: pure propylene emulsion 30.0-45.0 parts, water-based polyurethane emulsion 10.0-20.0 parts, titanium white 30.0-40.0 parts, film forming aid 3.0-8.0 parts, dispersing agent 1.5-3.0 parts, defoaming agent 0.2-0.4 parts, neutralizing agent 0.1-0.2 parts, water retaining agent 1.0-3.0 parts, thickening agent 0.3-1.0 parts, substrate wetting agent 0.1-0.5 parts, deionized water is made up to 100 parts;Its preparation method includes the steps of grinding slurry preparation, emulsion mixing, additive addition and filtration;The application is synergized by specific pure propylene emulsion and water-based polyurethane emulsion, so that primer dries rapidly, thick coating does not rise muscle with roll coating, and after being matched with UV fire-retardant topcoat, paint film is complete in fire resistance test without peeling, and has excellent anti-yellowing ability, suitable for high-grade fire-retardant coating of wood floor.

Description

Technical Field

[0001] This invention belongs to the field of water-based wood coatings technology, specifically relating to a flame-retardant water-based primer for wood flooring and its preparation method. Background Technology

[0002] Water-based wood coatings are increasingly widely used in the field of wood flooring coating due to their significant advantages such as environmental protection and low volatile organic compounds (VOCs). Among them, water-based white primer, as a key base layer of the coating system, undertakes the core functions of covering the original color of the substrate, filling the wood grain ducts, enhancing the adhesion of the topcoat, and improving the fullness of the coating.

[0003] With the increasing scarcity of global forest resources and the continuous reduction in the supply of high-quality large-diameter timber, the use of water-based white primers to make high-value use of low-grade timber has become an important trend in the industry. At the same time, based on the mandatory requirements of building fire protection codes for interior decoration materials, the development of water-based white primers that combine excellent construction performance and high-efficiency flame retardant function has become a technical problem that urgently needs to be solved in this field.

[0004] However, existing water-based white primers still face the following significant technical bottlenecks in practical applications:

[0005] 1. Conventional water-based primers are mostly based on pure acrylic or styrene-acrylic emulsions, which have a relatively slow drying speed. Especially in the case of thick coating by roller coating, the wood fibers on the surface are very likely to absorb water and swell, causing the "fiber swelling" phenomenon, which seriously damages the flatness of the board surface. If the amount of film-forming aids is excessively increased in order to pursue fast drying or a high glass transition temperature (Tg) emulsion is selected, it is easy to cause the paint film to become brittle, crack, and have reduced adhesion.

[0006] 2. Currently, most wood flooring uses a composite coating process of "water-based white base + UV flame-retardant topcoat". However, the interlayer adhesion between the existing water-based white base and UV flame-retardant coating is insufficient. Especially under the high temperature impact of fire resistance testing, the bottom white paint is very easy to delaminate from the wood substrate, which cannot meet the stringent requirements of B1 level and above flame retardant standards for coating integrity.

[0007] 3. Water-soluble substances such as tannins and pigments contained in wood are prone to migrate to the surface of the paint film under the action of moisture and heat, causing the white base to turn yellow and discolor. Existing technologies mostly rely on the physical hiding power of titanium dioxide for masking, but its blocking effect is still not ideal under extreme environments such as high temperature and high humidity, which seriously affects the overall appearance quality of the coating.

[0008] It is evident that existing water-based white primers have significant deficiencies in terms of drying resistance to bulging, compatibility with UV flame retardant systems, and long-term anti-yellowing capabilities, making it difficult to simultaneously meet the comprehensive requirements of high-grade flame retardant coatings.

[0009] Therefore, there is an urgent need to develop a water-based white primer that dries quickly, is not prone to bulging, has excellent high-temperature peel resistance when used with UV flame-retardant coatings, and has excellent anti-yellowing ability, in order to meet the industrial needs of high-grade flame-retardant coatings for wood flooring. Summary of the Invention

[0010] In view of the shortcomings of existing water-based white primers in terms of drying and anti-swelling properties, compatibility with UV flame retardant systems, and long-term anti-yellowing ability, this invention provides a flame-retardant water-based primer for wood flooring and its preparation method.

[0011] This primer, through the synergistic effect of a specific film-forming substance compound system and functional additives, achieves rapid drying and excellent workability while giving the coating film good adhesion to the UV flame-retardant topcoat. It also maintains excellent anti-yellowing ability in high temperature and high humidity environments, thus meeting the comprehensive requirements of high-grade flame-retardant coating for wood flooring.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A flame-retardant water-based primer comprises the following components in parts by weight: 30.0-45.0 parts of pure acrylic emulsion, 10.0-20.0 parts of water-based polyurethane emulsion, 30.0-40.0 parts of titanium dioxide, 3.0-8.0 parts of film-forming aid, 1.5-3.0 parts of dispersant, 0.2-0.4 parts of defoamer, 0.1-0.2 parts of neutralizer, 1.0-3.0 parts of water-retaining agent, 0.3-1.0 parts of thickener, 0.1-0.5 parts of substrate wetting agent, and the balance being deionized water to make up to 100 parts.

[0014] This formulation uses pure acrylic emulsion and waterborne polyurethane emulsion as composite film-forming substances. The pure acrylic emulsion imparts the coating film with rapid drying and high hardness, while the waterborne polyurethane emulsion provides good flexibility and adhesion. The two work synergistically within a specific ratio range, giving the coating film the dual advantages of rigid support and tough buffering, thereby effectively balancing the contradiction between drying speed and mechanical properties of the paint film.

[0015] In the above formulation, the preferred substrate wetting agent is a polyether-modified polysiloxane wetting agent, which can significantly reduce the dynamic surface tension of the paint, ensuring rapid spreading and sufficient wetting of the wood surface during roller coating, thereby effectively avoiding pinhole defects caused by poor wetting, and providing a good leveling foundation for thick coating.

[0016] The preferred film-forming aid is a mixture of dipropylene glycol methyl ether and dipropylene glycol butyl ether in a mass ratio of 3:2. This compound system can provide suitable agglomeration driving force for emulsion particles during the aqueous phase evaporation process, promote the full fusion and dense film formation of latex particles, and achieve rapid release while ensuring excellent film-forming effect, avoiding the negative impact of residue on the hardness of the paint film.

[0017] The thickener is preferably a nonionic polyurethane associative thickener, which constructs a three-dimensional network structure through the association of hydrophobic groups with the surfaces of emulsion particles and pigments and fillers, giving the system suitable rheological properties. During roller coating, it provides sufficient low shear viscosity, effectively controls the wet film thickness and prevents sagging in the thick coating state, while maintaining good fluidity at high shear rates to meet the construction requirements of roller coating transfer.

[0018] The water-retaining agent is a diol compound, which can slow down the evaporation rate of water in the system, providing a sufficient time window for the emulsion particles to fully integrate, and preventing problems such as excessively rapid surface drying, orange peel effect, or cracking of the paint film caused by excessively rapid evaporation of water.

[0019] For film-forming materials, pure acrylic emulsions with a glass transition temperature of not less than 40°C are preferred. This type of emulsion can achieve rapid surface drying and hard drying at room temperature, effectively shortening the coating cycle. Furthermore, its high cohesive energy provides the coating film with excellent anti-tack and surface hardness. For waterborne polyurethane emulsions, aliphatic polyurethane dispersions are preferred. The urethane bonds in its molecular structure endow the coating film with outstanding resistance to yellowing and low-temperature bending resistance. At the same time, it forms good compatibility with pure acrylic emulsions. The coating film formed by the combination of the two has both density and flexibility, and can effectively block the migration and penetration of water-soluble substances such as tannins and pigments inside the wood.

[0020] The preferred dispersant is a copolymer solution containing pigment affinity groups and / or a nonionic wetting and dispersing agent, which can effectively coat the surface of titanium dioxide particles, prevent pigment and filler agglomeration through steric hindrance and / or electrostatic repulsion, ensure stable dispersion and efficient deagglomeration of titanium dioxide in the system, and thus give full play to its covering efficiency.

[0021] The defoamer is preferably a polyether siloxane copolymer, which has both foam-suppressing and foam-breaking functions. During stirring, grinding, and application, it can quickly eliminate bubbles and inhibit the formation of new bubbles, thus preventing defects such as pinholes and blistering in the paint film. The neutralizing agent is preferably an organic amine and / or an inorganic base, used to adjust the pH value of the system to a suitable range, ensuring that all components coexist in an optimally dispersed and stable state.

[0022] The preferred titanium dioxide is rutile titanium dioxide, with a particle size D50 controlled below 0.3μm. This particle size range is an ideal scattering scale in the visible light wavelength range, which can provide the highest light scattering efficiency and ensure that the coating film has sufficient hiding power and whiteness even under low film thickness conditions. At the same time, the rutile lattice structure gives it excellent ultraviolet shielding ability, further suppressing photo-yellowing of the paint film.

[0023] This invention also provides a method for preparing a flame-retardant water-based primer, comprising the following steps:

[0024] After mixing deionized water and neutralizing agent evenly, add dispersant and continue stirring. Then add titanium dioxide, stir and grind until the fineness is no more than 15μm to obtain grinding slurry. Separately, disperse pure acrylic emulsion and substrate wetting agent evenly. Mix film-forming aid and defoamer and add to disperse until there are no pores. Then add grinding slurry and disperse evenly. Finally, add thickener and water-retaining agent and disperse evenly. Filter through a 200-mesh filter and adjust the viscosity to 50 seconds / cup No. 6 to obtain the finished product.

[0025] The above preparation method adopts a stepwise dispersion and stepwise mixing process. First, the titanium dioxide is dispersed to the target fineness by grinding to ensure the covering efficiency. Then, the emulsion and additives are gently mixed to avoid the damage of the latex particle structure by high shear. The finished product has excellent storage stability and construction adaptability.

[0026] Compared with the prior art, the flame-retardant water-based primer provided by the present invention has the following beneficial effects:

[0027] (1) By using pure acrylic emulsion with high glass transition temperature and aliphatic polyurethane dispersion as film-forming material, combined with a film-forming aid system of dipropylene glycol methyl ether and dipropylene glycol butyl ether in a mass ratio of 3:2 and a non-ionic polyurethane associative thickener, the resulting coating film dries rapidly under normal temperature conditions, which can effectively avoid the "swelling" phenomenon caused by the water absorption and swelling of wood fibers on the surface of the wood when roller coating thick coating, while ensuring that the paint film has good flexibility and adhesion, fundamentally solving the problem that drying speed and construction performance are difficult to balance in the existing technology.

[0028] (2) After the primer and UV flame retardant topcoat obtained by the present invention are combined and coated, the coating film and the wood substrate exhibit excellent heat-resistant peeling performance under the high temperature impact conditions of the fire resistance test. It can meet the stringent requirements of the B1 level and above flame retardant standards for coating integrity and effectively solve the problem of insufficient interlayer adhesion when existing water-based white primer and UV flame retardant system are matched.

[0029] (3) The present invention utilizes a dense composite resin film structure combined with the efficient light scattering and ultraviolet shielding capabilities of rutile titanium dioxide to effectively block the migration of water-soluble substances such as tannins and pigments inside wood under high temperature and high humidity conditions, significantly improving the long-term anti-yellowing level of the white base coat and ensuring the long-lasting stability of the overall coating appearance.

[0030] (4) The preparation process of this invention is simple, the raw materials are readily available, and the synergistic effect of each component is significant. It can achieve high-level flame retardant performance after being matched with flame retardant topcoat without the need for the addition of halogen or phosphorus flame retardants. It is suitable for large-scale promotion and application in the field of wood floor coating. Attached Figure Description

[0031] Figure 1 This is a process flow diagram of the preparation of a flame-retardant water-based primer for wood flooring according to the present invention. Detailed Implementation

[0032] To enhance understanding of the present invention, the invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only for explaining the invention and do not constitute a limitation on the scope of protection of the invention.

[0033] 1. Selection and source of raw materials

[0034] As a specific embodiment of the present invention, all components in the flame-retardant water-based primer can be made from commercially available industrial-grade raw materials.

[0035] Among them, the pure acrylic emulsion can be ALBERDINGK® AC2544, which has the characteristics of fast drying speed, high film hardness and excellent adhesion to wood substrate, and can provide the coating film with rapid initial strength; the waterborne polyurethane emulsion can be Wanhua 4210, which is an aliphatic polyurethane dispersion with good toughness, hardness and yellowing resistance, and can effectively make up for the lack of flexibility of pure acrylic emulsion.

[0036] For titanium dioxide, you can choose Longbai R996, which is a rutile titanium dioxide with the advantages of easy dispersion, high hiding power and pure whiteness.

[0037] The film-forming aids selected are DPM (dipropylene glycol methyl ether) and DPNB (dipropylene glycol butyl ether) from Dow Chemical, which are compounded at a mass ratio of 3:2.

[0038] TEGO 715W and / or TEGO 760W were selected as dispersants. The former is a copolymer solution containing pigment affinity groups, and the latter is a nonionic wetting and dispersing agent. The combination of the two can achieve the best dispersion and stability of pigments and fillers.

[0039] The defoamers selected are TEGO 810 and / or TEGO 904W, both of which are polyether siloxane copolymer defoamers that have both foam suppression and foam breaking functions.

[0040] Dimethylethanolamine and / or sodium hydroxide are selected as neutralizing agents to adjust the pH of the system to a weakly alkaline range of 8.0-9.0, ensuring the dispersion stability of each component.

[0041] Propylene glycol is selected as the water-retaining agent; Mingjia PU40W nonionic polyurethane associative thickener is selected as the thickener; WT100 polyether modified polysiloxane wetting agent can be selected as the substrate wetting agent.

[0042] 2. Scope of Formula Adjustment

[0043] In the specific implementation of this invention, the amount of each component can be adjusted within a certain range.

[0044] When faster drying speed and higher coating hardness are desired, the proportion of pure acrylic emulsion in the film-forming substance can be appropriately increased. The preferred range is 35.0-45.0 parts of pure acrylic emulsion and 10.0-15.0 parts of waterborne polyurethane emulsion.

[0045] When better flexibility, adhesion and low-temperature crack resistance are desired, the proportion of waterborne polyurethane emulsion can be appropriately increased, preferably in the range of 30.0-38.0 parts of pure acrylic emulsion and 15.0-20.0 parts of waterborne polyurethane emulsion.

[0046] The amount of titanium dioxide used can be adjusted according to the target hiding power. For dark wood substrates or wood with deep vascular bundles, the amount of titanium dioxide can be increased to 35.0-40.0 parts to enhance the hiding effect; for light wood substrates or wood with shallow vascular bundles, the amount can be reduced to 30.0-35.0 parts to reduce raw material costs.

[0047] The total amount of film-forming aids used is closely related to the ambient temperature and humidity. Under low temperature (<15℃) or high humidity (>80%RH) conditions, it is recommended to use the upper limit of 6.0-8.0 parts to ensure sufficient film formation. Under high temperature (>30℃) or low humidity (<40%RH) conditions, it is recommended to use the lower limit of 3.0-5.0 parts to avoid slow drying or residue.

[0048] The amount of thickener should be adjusted according to the target application viscosity. When applying by roller coating, adjusting the viscosity to 45-55 seconds using a No. 6 cup (25℃) will achieve the best coating and leveling effect.

[0049] The amount of substrate wetting agent can be adjusted within the range of 0.1-0.5 parts. For wood substrates with low surface tension or difficult to wet, the amount can be increased to 0.3-0.5 parts to ensure full spreading; for conventional substrates, 0.1-0.2 parts is sufficient.

[0050] 3. Control of process parameters in the preparation method

[0051] In the preparation method of the present invention, the process conditions of each step have a significant impact on the performance of the final product.

[0052] In step (1), the mixing time of deionized water and neutralizing agent is preferably 3-5 minutes, and the stirring speed is controlled at 300-500 rpm to ensure that the neutralizing agent is completely dissolved and dispersed in the system and achieves a uniform pH environment.

[0053] After adding the dispersant in step (2), continue stirring for 3-5 minutes to allow the dispersant to be fully adsorbed onto the surface of the subsequently added titanium dioxide particles.

[0054] In step (3), the grinding process can be carried out using a horizontal sand mill or a basket sand mill. The preferred grinding media is zirconia beads, with a filling rate controlled at 70%-80%. The grinding temperature is controlled below 50℃ to prevent damage to the titanium dioxide surface coating. The grinding is carried out to a fineness of no more than 15μm, preferably controlled at 10-12μm to obtain the best covering efficiency and storage stability.

[0055] In step (4), the pure acrylic emulsion and the substrate wetting agent are dispersed evenly under low shear conditions (200-300 rpm) to avoid high-speed shearing damaging the emulsion particle structure; the film-forming aid and defoamer need to be mixed evenly before being added, and after being added, they should be dispersed at 400-600 rpm until the system is free of shrinkage cavities, usually for 8-12 minutes; after adding the grinding slurry, continue to disperse for 15-20 minutes until the system has a uniform color.

[0056] After adding the thickener and water-retaining agent in step (5), disperse for 10-15 minutes at 300-500 rpm to allow the thickener to fully hydrate and swell and establish a stable rheological network structure; use a 200-mesh filter to remove any mechanical impurities or undispersed particles to ensure the product has a pure appearance; adjust the viscosity to 50 seconds for cup 6 (25℃). Under this viscosity condition, roller coating can achieve the best wet film coating amount and leveling effect.

[0057] 4. Construction and application of the product

[0058] When using flame-retardant water-based primers, it is preferable to apply them by roller coating after adding a water-based crosslinking agent.

[0059] The amount of water-based crosslinking agent added can be adjusted according to the required crosslinking density, preferably 3%-8% of the total mass of the primer.

[0060] Before construction, the wood flooring substrate should be routinely treated, including sanding and dust removal.

[0061] When using roller coating, it is recommended that the wet film coating amount for a single coat be 80-120 g / m², which can be adjusted appropriately according to the water absorption of the substrate and the depth of the conduit.

[0062] After roller coating, the surface drying time is about 15-30 minutes and the actual drying time is about 2-4 hours under normal temperature conditions. After the primer is completely dry, sanding is performed, and then the UV flame retardant topcoat is applied.

[0063] The primer and UV flame-retardant topcoat have good interlayer adhesion. After the UV flame-retardant topcoat is applied, the fire resistance rating can be tested according to relevant standards.

[0064] 5. Product storage and stability

[0065] The flame-retardant water-based primer obtained by this invention, when stored in a cool, dry environment at 5-35°C under sealed packaging conditions, has a shelf life of not less than 12 months.

[0066] The product should be stored away from freezing and exposure to high temperatures, and should be stirred well before use.

[0067] Implementation Example

[0068] 1. Formulation composition of Examples 1-3

[0069] According to the formulations shown in Table 1, flame-retardant water-based primers of Examples 1, 2 and 3 were prepared respectively. The amount of each component is in parts by weight, and deionized water was added to make up to 100 parts.

[0070] Table 1. Formulation composition of Examples 1-3

[0071] Deionized water 13.8 13.8 13.8 Dimethylethanolamine 0.2 0.2 0.2 715W 0.5 0.5 0.5 760W 1 1 1 WT100 0.2 0.2 0.2 R996 32 32 32 AC2544 45 0 15 4210 0 45 30 DPNB 2 2 2 DPM 3 3 3 Tego810 0.3 0.3 0.3 Propylene glycol 1.5 1.5 1.5 PU40W 0.5 0.5 0.5 total 100 100 100

[0072] In Example 1, pure acrylic emulsion AC2544 was used as the sole film-forming substance, without any aqueous polyurethane emulsion; in Example 2, aqueous polyurethane emulsion Wanhua 4210 was used as the sole film-forming substance, without any pure acrylic emulsion; in Example 3, pure acrylic emulsion AC2544 and aqueous polyurethane emulsion Wanhua 4210 were compounded at a mass ratio of 15:30 as the film-forming substance, with a total of 45 parts, consistent with the total amount of film-forming substances used in Examples 1 and 2.

[0073] 2. Preparation process of Examples 1-3

[0074] The preparation methods of Examples 1-3 are all carried out according to the following steps: First, deionized water and dimethylethanolamine are added to a dispersion vessel and stirred at 400 rpm for 3 minutes; then TEGO 715W and TEGO 760W dispersants are added in sequence and stirred for another 5 minutes; then R996 titanium dioxide is added and stirred and dispersed at 800 rpm for 15 minutes, and then transferred to a horizontal sand mill and ground with zirconia beads as the grinding medium until the fineness is no more than 15 μm to obtain a grinding slurry.

[0075] In a separate paint mixing tank, AC2544 and / or Wanhua 4210 emulsion and WT100 substrate wetting agent are stirred and dispersed evenly at 300 rpm. DPNB, DPM and TEGO 810 defoamer are pre-mixed and added to the paint mixing tank. The speed is increased to 500 rpm and dispersed until the system is free of pinholes. Then, the above grinding slurry is added and dispersion is continued for 15 minutes.

[0076] Finally, add PU40W thickener and propylene glycol water-retaining agent, stir and disperse at 400 rpm for 10 minutes until the system is uniform, filter the material through a 200-mesh filter, and adjust the viscosity to 50 seconds for cup 6 (25℃) to obtain the finished product.

[0077] 3. Performance tests of Examples 1-3

[0078] The white primers prepared in Examples 1-3 were added to an aqueous crosslinking agent and then applied to the surface of a wood flooring substrate that had been sanded and dust-removed by roller coating. The single wet film coating amount was 100 g / m². After drying at room temperature for 4 hours, the substrate was sanded and then coated with a UV flame-retardant topcoat according to conventional processes to complete the composite coating. The performance of the resulting coated samples was tested, and the results are shown in Table 2.

[0079] Table 2 Performance test results of Examples 1-3

[0080] Adhesion (100-grid test) Level 3 Level 1 Level 1 Water resistant at 70℃ for 4 hours Shedding No bubbling, no peeling No bubbling, no peeling Fire resistance rating Grade B1, paint film intact Grade B2, paint film peeling. Grade B1, paint film intact

[0081] As shown in Table 2, when pure acrylic emulsion was used as the only film-forming substance in Example 1, although the integrity of the paint film was good (B1 level) in the fire resistance test, the adhesion was poor (3 level), and the paint film peeled off after being soaked in hot water at 70°C for 4 hours. This indicates that when pure acrylic emulsion is used alone, the coating film is brittle and lacks flexibility, resulting in a decrease in interfacial bonding strength under high temperature and high humidity conditions.

[0082] In Example 2, when waterborne polyurethane emulsion was used as the only film-forming substance, the adhesion was excellent (Level 1) and the water resistance was good. However, the fire resistance rating was only B2 and the paint film peeled off during the test, indicating that the high-temperature stability of the coating film was insufficient when waterborne polyurethane was used alone, and it could not maintain the complete coating structure under the high-temperature impact of open flame burning.

[0083] In Example 3, when pure acrylic emulsion and waterborne polyurethane emulsion were combined as film-forming substances, excellent adhesion (Grade 1), outstanding water resistance (no bubbling, no peeling) and the highest fire resistance rating (Grade B1, intact film) were simultaneously obtained. This indicates that the two substances formed an ideal synergistic effect at a mass ratio of 15:30. The pure acrylic emulsion provided high-temperature structural stability and rigid support for the coating film, while the waterborne polyurethane emulsion provided interfacial adhesion and flexible buffering. The two substances complemented each other and together endowed the composite coating film with integrity and substrate adhesion stability under high-temperature impact.

[0084] 4. Analysis of Implementation Results

[0085] The above embodiments verify the technical effects of the flame-retardant water-based primer described in this invention:

[0086] In the compound system of pure acrylic emulsion and waterborne polyurethane emulsion, the pure acrylic emulsion, due to its high glass transition temperature (the Tg of AC2544 is about 40-45℃), endows the coating film with the characteristics of rapid drying, high hardness and structural stability at high temperature. The waterborne polyurethane emulsion, due to the flexibility of its molecular chain and the content of polar groups, provides excellent substrate wetting and adhesion ability as well as the buffering and absorption of thermal stress.

[0087] The synergistic effect of the two is not only reflected in the conventional adhesion and water resistance performance, but more importantly, under high temperature fire resistance test conditions, the composite coating can maintain the integrity of the coating structure without peeling during thermal shock, thus meeting the requirements of the B1 flame retardant standard for coating integrity.

[0088] In addition, the compound system, combined with the high hiding power and UV shielding ability of rutile titanium dioxide R996, and the precise control of the water evaporation rate by propylene glycol water-retaining agent, enables the coating film to effectively inhibit the migration and penetration of water-soluble substances such as tannins inside the wood under high temperature and high humidity conditions, thus achieving a long-lasting anti-yellowing effect.

[0089] In summary, the flame-retardant water-based primer and its preparation method provided by this invention have significant advantages such as fast drying, no bulging, excellent high-temperature peel resistance and high anti-yellowing level when used with UV flame-retardant topcoat. It is suitable for high-grade flame-retardant coating of wood flooring and has good prospects for industrial application.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flame-retardant water-based primer, characterized in that, It contains the following components in parts by weight: Pure acrylic emulsion, 30.0-45.0 parts; 10.0-20.0 parts of waterborne polyurethane emulsion; Titanium dioxide 30.0-40.0 parts; Film-forming aid 3.0-8.0 parts; Dispersant 1.5-3.0 parts; Defoamer 0.2-0.4 parts; Neutralizing agent 0.1-0.2 parts; Water-retaining agent: 1.0-3.0 parts; Thickener 0.3-1.0 parts; Substrate wetting agent 0.1-0.5 parts; Add deionized water to bring the total to 100 parts.

2. The flame-retardant water-based primer according to claim 1, characterized in that: The substrate wetting agent is a polyether-modified polysiloxane.

3. The flame-retardant water-based primer according to claim 1, characterized in that: The film-forming aid is a mixture of dipropylene glycol methyl ether and dipropylene glycol butyl ether, with a mass ratio of 3:

2.

4. The flame-retardant water-based primer according to claim 1, characterized in that: The thickener is a nonionic polyurethane associative thickener.

5. The flame-retardant water-based primer according to claim 1, characterized in that: The pure acrylic emulsion is a pure acrylic emulsion with a glass transition temperature ≥ 40℃; the aqueous polyurethane emulsion is an aliphatic polyurethane dispersion.

6. The flame-retardant water-based primer according to claim 1, characterized in that: The dispersant is a copolymer solution containing pigment affinity groups and / or a nonionic wetting and dispersing agent; the defoamer is a polyether siloxane copolymer; the neutralizing agent is an organic amine and / or an inorganic base; and the water-retaining agent is a diol.

7. The flame-retardant water-based primer according to claim 1, characterized in that: The titanium dioxide is rutile titanium dioxide with a particle size D50 ≤ 0.3 μm.

8. A method for preparing a flame-retardant water-based primer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Mix the deionized water and neutralizing agent thoroughly; (2) Add dispersant and continue stirring; (3) Add titanium dioxide, stir and grind until the fineness is ≤15μm to obtain grinding slurry; (4) Disperse the pure acrylic emulsion and the substrate wetting agent evenly, then mix the film-forming aid and the defoamer and add them, disperse until there are no shrinkage cavities, and then add the grinding slurry obtained in step (3) and disperse it evenly; (5) Finally, add thickener and water-retaining agent, disperse evenly and filter to obtain the final product.

9. The preparation method according to claim 8, characterized in that: The substrate wetting agent mentioned in step (4) is polyether-modified polysiloxane.

10. The preparation method according to claim 8, characterized in that: The filtration in step (5) uses a 200-mesh filter and the product viscosity is adjusted to 50 seconds / cup No. 6.

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