Far infrared paint for floor and method for preparing the same

Abstract

The present application relates to the field of paint technology, in particular to a kind of far infrared paint for floor and preparation method thereof.The paint takes far infrared organic-inorganic hybrid tung oil resin and core-shell far infrared nanoceramic powder as main components, hybrid resin is grafted with tetraethoxysilane and titanium acid tetraisopropyl ester hydrolysis polycondensation after epoxidized tung oil silane, to form Si-O-Si and Si-O-Ti network;Core-shell far infrared nanoceramic powder is coated with polydopamine, branched polyethyleneimine and tannic acid layer.The preparation method includes epoxidation, grafting, polycondensation, core-shell modification and mixing dispersion.The paint has high far infrared emissivity, excellent wear resistance and water resistance, and is storage stable, while retaining natural oil permeability and wood texture.

Description

Technical Field

[0001] This invention relates to the field of paint technology, and in particular to a far-infrared paint for flooring and its preparation method. Background Technology

[0002] Natural oil-based floor coatings are favored in high-end home furnishings and environmentally friendly decoration sectors due to their excellent penetration into wood and preservation of natural textures. These coatings typically use drying oils such as tung oil and linseed oil as the main film-forming substances. The film is formed through oxidative cross-linking triggered by oxygen in the air, giving the floor a soft texture and repairability. However, these coatings reveal significant limitations with long-term use: their molecular chains are mainly composed of flexible fatty acid chains, resulting in limited cross-linking density and generally low hardness, making them susceptible to wear and tear from furniture movement and shoe soles; simultaneously, the polar residues and microporous structure in the oily film easily absorb moisture from the environment, causing swelling, whitening, and even peeling, especially in humid, clean, or high-humidity environments where durability significantly decreases.

[0003] To further improve wear and water resistance, some studies have attempted to introduce inorganic nanoparticles or highly cross-linked resins into oil-based systems for physical blending. For example, adding hard fillers such as silica and alumina, or compounding with polyurethane or acrylic resins, while improving surface hardness to some extent, often sacrifices the unique penetrating power and wood-like feel of natural oils. More importantly, simple physical mixing makes it difficult to achieve long-term stable dispersion of functional components in the oil phase. After storage and film formation, filler sedimentation and agglomeration easily occur, resulting in uneven coating microstructure, which in turn accelerates local wear or moisture intrusion. Furthermore, this type of modification does not solve the problem of functional uniformity and cannot meet the upgraded demands for health and comfort in modern living environments.

[0004] Far-infrared radiating materials, such as ceramic powder and silicon carbide, have been proven to raise the surface temperature of objects through radiation effects, and their application in building materials can improve indoor thermal comfort. However, introducing far-infrared functionality into floor coatings faces technical challenges: if a high proportion of far-infrared fillers is added externally, it significantly increases the system viscosity, hindering the penetration of oil-based components into the wood, while also exacerbating coating embrittlement and losing the flexibility and repairability of natural oil coatings; on the other hand, if surface coating or composite film processes are used, there are problems such as poor adhesion, complex processes, high costs, and easy wear and peeling of the functional layer. Current technologies have not yet been able to achieve an organic unity of wear resistance, water resistance, and far-infrared functionality while retaining the core advantages of natural oil coatings. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a far-infrared paint for flooring and its preparation method, so as to endow the flooring coating with a long-lasting and stable far-infrared radiation function while maintaining the permeability, wood texture and repairability of natural oil coatings, and simultaneously improve its wear resistance and water resistance.

[0006] To achieve the above objectives, the present invention provides a far-infrared paint for flooring, comprising, by weight, the following raw materials: 520 parts of the far-infrared organic-inorganic hybrid tung oil resin, 30-60 parts of the core-shell far-infrared nano-ceramic powder, 200 parts of butyl acetate, 80-120 parts of ethyl acetate, 40-60 parts of 2-propanol, 40-70 parts of isoparaffin solvent oil, 6-10 parts of wetting and dispersing agent, 8-15 parts of wear-resistant wax powder, 2-3 parts of cobalt(II) 2-ethylhexanoate mineral oil solution, 5-7 parts of zirconium(IV) 2-ethylhexanoate mineral oil solution, 2-3 parts of calcium 2-ethylhexanoate, and 3-4 parts of 2-butanone oxime.

[0007] Furthermore, the core-shell far-infrared nano-ceramic powder includes a far-infrared nano-ceramic powder core and a shell layer covering the surface of the far-infrared nano-ceramic powder core. The shell layer is composed of a polydopamine deposition layer formed by dopamine oxidation self-polymerization, a branched polyethyleneimine layer, and a tannic acid layer. The branched polyethyleneimine layer includes branched polyethyleneimine with a weight average molecular weight of 600-1000 and branched polyethyleneimine with a weight average molecular weight of 20000-30000.

[0008] Furthermore, the far-infrared organic-inorganic hybrid tung oil resin comprises tung oil organic segments and an organic-inorganic hybrid network containing Si-O-Si bonds and Si-O-Ti bonds. The far-infrared organic-inorganic hybrid tung oil resin is obtained by reacting epoxidized tung oil with 3-aminopropyltriethoxysilane to obtain silane-grafted epoxidized tung oil, which is then further hydrolyzed and condensed with tetraethoxysilane and tetraisopropyl titanate.

[0009] Furthermore, it also includes 4 parts rheology modifier, 3 parts leveling agent, and 3 parts defoamer.

[0010] Preferably, the rheology modifier is RHEOBYK-410, the leveling agent is BYK-333, and the defoamer is BYK-054.

[0011] Preferably, the wetting and dispersing agent is DISPERBYK-110; and the abrasion-resistant wax powder is CERAFLOUR1050.

[0012] Preferably, in the raw materials for preparing the core-shell far-infrared nano-ceramic powder, the mass ratio of far-infrared nano-ceramic powder core, dopamine, branched polyethyleneimine with a weight average molecular weight of 600-1000, branched polyethyleneimine with a weight average molecular weight of 20000-30000, and tannic acid is 30-60:3-6:1-3:2-5:3-6.

[0013] Preferably, in the raw materials for preparing the far-infrared organic-inorganic hybrid tung oil resin, the mass ratio of epoxidized tung oil, 3-aminopropyltriethoxysilane, tetraisopropyl titanate, and tetraethoxysilane is 520:60-110:20-45:25-70.

[0014] Preferably, epoxidized tung oil is obtained by in-situ generation of performic acid from formic acid and hydrogen peroxide, which epoxidizes the unsaturated double bonds of tung oil to introduce epoxidation reaction sites.

[0015] Furthermore, the present invention also provides a method for preparing far-infrared paint for flooring, comprising the following steps:

[0016] (1) Tung oil is epoxidized to obtain epoxidized tung oil;

[0017] (2) The epoxidized tung oil is grafted with 3-aminopropyltriethoxysilane to obtain silane-grafted epoxidized tung oil;

[0018] (3) The silane-grafted epoxidized tung oil is hydrolyzed and polycondensed with tetraethoxysilane and tetraisopropyl titanate to obtain far-infrared organic-inorganic hybrid tung oil resin.

[0019] (4) Using far-infrared nano-ceramic powder as the core, core-shell far-infrared nano-ceramic powder is obtained by dopamine oxidation self-polymerization deposition and combined with branched polyethyleneimine and tannic acid surface modification.

[0020] (5) The far-infrared organic-inorganic hybrid tung oil resin obtained in step (3) and the core-shell far-infrared nano-ceramic powder obtained in step (4) are mixed and dispersed in a solvent to obtain far-infrared paint for flooring.

[0021] Preferably, step (4) includes: adding deionized water and sodium bicarbonate to the reaction vessel and stirring to dissolve them; adding far-infrared nano-ceramic powder and dispersing it to form a slurry; adding dopamine hydrochloride and stirring in an open container for 2 hours to allow it to oxidize and self-polymerize and deposit on the surface of the far-infrared nano-ceramic powder; then adding branched polyethyleneimine with a weight-average molecular weight of 800 and stirring for another 4 hours; filtering, separating, washing and drying to constant weight; then adding deionized water and 2-propanol and dispersing for 10 minutes; adding 2-5 parts of branched polyethyleneimine with a weight-average molecular weight of 25,000 and stirring for 1 hour; dissolving tannic acid in deionized water and adding it to the mixture and stirring for another 1 hour; then filtering, separating, washing and drying to constant weight to obtain core-shell far-infrared nano-ceramic powder.

[0022] Preferably, step (5) includes: adding butyl acetate and wetting and dispersing agent to a dispersion tank, adding core-shell far-infrared nano-ceramic powder under stirring and dispersing at 2000 rpm for 30 min; adding far-infrared organic-inorganic hybrid tung oil resin and butyl acetate at 500 rpm and stirring for 20 min; then adding ethyl acetate, 2-propanol and isoparaffin solvent oil and stirring for 10 min; subsequently adding rheology modifier and wear-resistant wax powder and stirring for 20 min, adding leveling agent and defoamer and stirring for 10 min, adding cobalt(II) 2-ethylhexanoate mineral oil solution, zirconium(IV) 2-ethylhexanoate mineral oil solution, calcium 2-ethylhexanoate and 2-butanone oxime and stirring for 10 min, and filtering through 100 mesh to obtain far-infrared paint for flooring.

[0023] The beneficial effects of this invention are:

[0024] This invention employs a molecular-level epoxidation design on tung oil-based materials, preserving their oxidative curing properties while providing precise reaction sites for subsequent functionalization modifications. This strategy enables directional grafting of the organic phase under mild conditions, avoiding the decreased permeability and loss of flexibility caused by traditional high cross-linking or high filler introduction, thus laying a structural foundation for the in-situ anchoring of functional components.

[0025] By utilizing the ring-opening grafting reaction of silane compounds, covalently linked active end groups were constructed on the oil molecular chain, achieving a chemical bridge between the organic segments and the inorganic network. This structure allows the subsequently formed hybrid network to be uniformly distributed within the film-forming system, effectively suppressing macroscopic phase separation of the inorganic phase, significantly enhancing the adhesion of the coating to wood and its resistance to water bleaching, while also providing a stable carrier framework for the far-infrared radiation unit.

[0026] Through in-situ hydrolysis and condensation of siloxanes and titanates, nanoscale Si-O-Si and Si-O-Ti crosslinked networks were formed within the oil phase. These networks, chemically anchored to the organic framework, not only enhance the rigidity and density of the coating but also contribute highly efficient far-infrared radiation performance due to their unique lattice vibration characteristics. This achieves simultaneous enhancement of wear resistance, improved water resistance, and integrated thermal functionality with low inorganic content.

[0027] A core-shell construction strategy combining dopamine oxidative self-polymerization and gradient molecular modification was employed to form a dense coating layer with varying interfacial energy on the surface of far-infrared functional particles. The inner layer's strongly polar anchoring groups ensured a strong bond between the particles and the hybrid resin, while the outer layer's low surface energy structure significantly inhibited moisture adsorption and particle aggregation. This enabled the functional filler to maintain long-term dispersion stability in high-solids, oil-containing systems, resulting in a more uniform and lasting far-infrared effect.

[0028] The time-series controlled surface modification process optimizes the spatial distribution configuration of modifiers of different molecular weights on the particle surface. First, low molecular weight polymers are used to enhance the interfacial bonding density, then high molecular weight polymers are introduced to form a three-dimensional barrier, and finally, polyphenol crosslinking is used to strengthen the integrity of the coating layer. This sequence effectively avoids agglomeration instability and achieves a comprehensive effect of synergistic improvement in water resistance, abrasion resistance, far-infrared radiation, and workability. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0030] Raw material source and specifications:

[0031] Tung oil: Merck Sigma-Aldrich, product number 440337, natural oil raw material; Formic acid: Merck Sigma-Aldrich, product number F0507; Hydrogen peroxide solution: Merck Sigma-Aldrich, product number H1009, 30% by mass (including stabilizer); Cobalt(II) 2-ethylhexanoate mineral oil solution: Merck Sigma-Aldrich, product number 444545, content 65wt%; Zirconium(IV) 2-ethylhexanoate mineral oil solution: Merck Sigma-Aldrich, product number 768634, zirconium content approximately 6%; Calcium 2-ethylhexanoate: Merck Sigma-Aldrich, product number 362964, purity 98%; Tannic acid: Merck Sigma-Aldrich, product number 403040; Branched polyethyleneimine (weight average molecular weight approximately 800): Merck Sigma-Aldrich, product number 408719; branched polyethyleneimine (weight average molecular weight approximately 25,000): Merck Sigma-Aldrich, product number 408727; far-infrared nano-ceramic powder is titanium dioxide (trade name AEROXIDE titanium dioxide P25): Tokyo Chemical Industry Co., Ltd., product number T4118, specific surface area approximately 50 m². 2 / g, with an average particle size of approximately 21nm and a rutile / anatase ratio of approximately 20 / 80.

[0032] Example 1:

[0033] Step 1: Add 500g of tung oil and 50g of formic acid to a four-necked flask equipped with a mechanical stirrer, thermometer, and dropping funnel. Heat to 45℃ while stirring at 400rpm. Then, add 200g of hydrogen peroxide solution (30% by mass) dropwise over 60min using a dropping funnel, maintaining the system temperature at 50-55℃ during the addition. After the addition is complete, continue the reaction at 55℃ for 3h. After the reaction, cool to 30℃, add 200g of deionized water, allow to stand for phase separation, and discard the aqueous phase. Repeat the washing process once with another 200g of deionized water. Then, dissolve 30g of sodium bicarbonate in 200g of deionized water to prepare a sodium bicarbonate solution. Add this solution to the organic phase in batches and stir for 10min to neutralize residual acid. Allow to stand for phase separation and discard the aqueous phase. Dehydrate and volatilize the obtained organic phase under reduced pressure at 60℃ and 5kPa until the organic phase mass is 520g, yielding epoxidized tung oil.

[0034] Step 2: Add 520g of epoxidized tung oil, 100g of butyl acetate and 80g of 3-aminopropyltriethoxysilane to a dry four-necked flask. After purging with nitrogen for 10 minutes, heat to 70℃ under nitrogen protection and stir at 500rpm for 4 hours. After the reaction is complete, remove butyl acetate and a small amount of low-boiling substances generated by the reaction under reduced pressure at 70℃ and 5kPa. Control the removal until the mass of the system is 570g to obtain silane-grafted epoxidized tung oil.

[0035] Step 3: In a dry beaker, mix 3g of acetylacetone and 30g of tetraisopropyl titanate and stir at 25°C for 10 minutes to prepare a tetraisopropyl titanate complex solution; in a separate dry flask, add 120g of 2-propanol and 40g of tetraethoxysilane and stir for 10 minutes, then add the tetraisopropyl titanate complex solution and continue stirring for 10 minutes; then mix 20g of deionized water, 3g of glacial acetic acid, and 20g of 2-propanol to prepare a hydrolysis catalyst solution, and add it dropwise to the above mixture at 25°C over 30 minutes. After the addition is complete, continue stirring for 30 minutes to obtain a pre-hydrolyzed sol; then mix 570g of silane-grafted epoxidized tung oil and 50g of... 2-Propanol was added to a four-necked flask, and after purging with nitrogen for 10 min, the temperature was raised to 50 °C with stirring at 600 rpm. The pre-hydrolyzed sol was added within 30 min and the reaction was maintained at 50 °C for 1 h. Then the temperature was raised to 80 °C and the reaction was carried out for 2 h. After the reaction was completed, the alcohol and a small amount of water generated were removed under reduced pressure at 80 °C and 5 kPa. The removal was controlled to a system mass of 640 g to obtain far-infrared organic-inorganic hybrid tung oil resin.

[0036] Step 4: Add 1000g of deionized water and 8g of sodium bicarbonate to the reaction vessel and stir to dissolve. Add 40g of far-infrared nano-ceramic powder and disperse at 2000rpm for 20min to form a uniform slurry. Add 4g of dopamine hydrochloride at 25℃ and 400rpm and stir openly for 2h to allow it to undergo oxidative self-polymerization and deposition on the surface of the far-infrared nano-ceramic powder under weak alkalinity and dissolved oxygen. Then add 2g of branched polyethyleneimine (weight average molecular weight approximately 800) and continue stirring for 4h. After the reaction, separate the solid by filtration and wash twice with 500g of deionized water. Finally, vacuum dry at 60℃ to constant weight, and then add 300g of deionized water and 200g of... 2-Propanol was dispersed at 1500 rpm for 10 min, and 3 g of branched polyethyleneimine (weight average molecular weight of about 25000) was added at 25 °C and 300 rpm and stirred for 1 h. 4 g of tannic acid was dissolved in 100 g of deionized water and added to the mixture, and stirring was continued for 1 h. The solid was then filtered to separate it and washed once each with 300 g of deionized water and 200 g of 2-propanol. The solid was then vacuum dried at 60 °C to constant weight to obtain core-shell far-infrared nano-ceramic powder.

[0037] Step 5: Add 100g butyl acetate and 8g wetting and dispersing agent DISPERBYK-110 to the dispersion tank, add 40g core-shell far-infrared nano-ceramic powder while stirring, and disperse at 2000rpm for 30min; add 520g far-infrared organic-inorganic hybrid tung oil resin and 100g butyl acetate at 500rpm and stir for 20min; then add 100g ethyl acetate, 50g 2-propanol and 50g isoparaffin solvent oil IsoparL and stir for 10min; subsequently add 4g rheology modifier RHEOBYK-410 and 10g wear-resistant wax powder CERAFLOUR1050 and stir for 20min; add 3g leveling agent BYK-333 and 3g defoamer BYK-054 and stir for 10min; finally add 2g cobalt(II) 2-ethylhexanoate mineral oil solution, 5g zirconium(IV) 2-ethylhexanoate mineral oil solution, 2g calcium 2-ethylhexanoate and 3g... Stir 2-butanone oxime for 10 minutes, filter through 100 mesh to obtain far-infrared paint for flooring;

[0038] Step 6: Sand the wood flooring surface to be coated to P180 and remove dust, maintaining environmental conditions at 25℃ and 50% relative humidity; use a short-pile roller with a spray rate of 40g / m². 2 Apply the far-infrared paint for flooring evenly, let it stand and penetrate for 20 minutes, then wipe off the surface oil with a clean non-woven cloth and keep the coating thin. After an 8-hour interval, apply another coat using the same method. Avoid water contact and heavy pressure within 24 hours after application, and avoid dragging and abrasion within 72 hours. The coating will reach a stable curing state in 7 days, resulting in a floor coating that combines the texture of wood, wear resistance, water resistance, and far-infrared function.

[0039] Example 2:

[0040] Based on Example 1, in step 1, the amount of formic acid used was 40g, the amount of hydrogen peroxide solution used was 180g, the dropping time was 50min, and after the dropping was completed, the reaction was kept at 55℃ for 2.5h; in step 2, the amount of butyl acetate used was 120g, the amount of 3-aminopropyltriethoxysilane used was 60g, the reaction temperature was 65℃, and the reaction time was 3h; in step 3, the amount of acetylacetone used was 2g, the amount of tetraisopropyl titanate used was 20g, the amount of 2-propanol used was 140g, the amount of tetraethoxysilane used was 25g, and the amount of deionized water, glacial acetic acid, and 2-propanol in the hydrolysis catalyst solution was 12g, the amount of glacial acetic acid used was 2g, the dropping time of the hydrolysis catalyst solution was 50min, and the temperature was raised to The reaction time was 1.5 hours at 80°C. In step 4, the amounts of sodium bicarbonate were 6 g, far-infrared nano-ceramic powder 30 g, dopamine hydrochloride 3 g, branched polyethyleneimine (weight average molecular weight approximately 800) 1 g, branched polyethyleneimine (weight average molecular weight approximately 25,000) 2 g, and tannic acid 3 g. In step 5, the amounts of wetting and dispersing agent DISPERBYK-110 were 6 g, core-shell far-infrared nano-ceramic powder 30 g, ethyl acetate 80 g, 2-propanol 40 g, isoparaffin solvent oil IsoparL 40 g, and abrasion-resistant wax powder CERAFLOUR 1050 8 g. All other conditions were the same as in Example 1.

[0041] Example 3:

[0042] Based on Example 1, in step 1, the amount of formic acid used was 60g, the amount of hydrogen peroxide solution used was 220g, the dropping time was 70min, and after the dropping was completed, the reaction was kept at 55℃ for 3.5h; in step 2, the amount of butyl acetate used was 80g, the amount of 3-aminopropyltriethoxysilane used was 110g, the reaction temperature was 75℃, and the reaction time was 5h; in step 3, the amount of acetylacetone used was 5g, the amount of tetraisopropyl titanate used was 45g, the amount of 2-propanol used was 100g, the amount of tetraethoxysilane used was 70g, and the amount of deionized water, glacial acetic acid, and 25g of 2-propanol used in the hydrolysis catalyst was 35g, the amount of deionized water was 5g, the amount of glacial acetic acid used was 25g, the dropping time of the hydrolysis catalyst was 40min, and the reaction time was raised to 85℃ for 3h; in step 4, the amount of sodium bicarbonate used was 10g, and the amount of far-infrared nano-ceramic powder used was... The total amount of the following components was 60g: dopamine hydrochloride 6g, branched polyethyleneimine (weight average molecular weight approximately 800) 3g, branched polyethyleneimine (weight average molecular weight approximately 25000) 5g, and tannic acid 6g. In step 5, the wetting and dispersing agent DISPERBYK-110 was 10g, the core-shell far-infrared nano-ceramic powder was 60g, ethyl acetate was 120g, 2-propanol was 60g, isoparaffin solvent oil IsoparL was 70g, abrasion-resistant wax powder CERAFLOUR 1050 was 15g, cobalt(II) 2-ethylhexanoate mineral oil solution was 3g, zirconium(IV) 2-ethylhexanoate mineral oil solution was 6g, calcium 2-ethylhexanoate was 3g, and 2-butanone oxime was 4g. All other conditions were the same as in Example 1.

[0043] Example 4:

[0044] Based on Example 1, in step 1, the amount of formic acid used was 45g and the amount of hydrogen peroxide solution used was 190g; in step 2, the amount of 3-aminopropyltriethoxysilane used was 90g; in step 3, the amount of tetraethoxysilane used was 50g and the amount of deionized water in the hydrolysis catalyst was 25g; in step 4, the amount of far-infrared nano-ceramic powder used was 50g, the amount of dopamine hydrochloride used was 5g, the amount of branched polyethyleneimine (weight average molecular weight approximately 25,000) used was 4g, and the amount of tannic acid used was 5g; in step 5, the amount of core-shell far-infrared nano-ceramic powder used was 50g and the amount of wear-resistant wax powder CERAFLOUR1050 used was 12g. All other conditions were the same as in Example 1.

[0045] Example 5:

[0046] Based on Example 1, in step 1, the amount of formic acid was 55g and the amount of hydrogen peroxide solution was 210g; in step 2, the amount of butyl acetate was 110g and the amount of 3-aminopropyltriethoxysilane was 100g; in step 3, the amount of acetylacetone was 4g, the amount of tetraisopropyl titanate was 40g, the amount of tetraethoxysilane was 60g, and the amount of deionized water, glacial acetic acid, and 2-propanol in the hydrolysis catalyst solution was 30g, the amount of glacial acetic acid was 4g, and the amount of 2-propanol was 25g; the temperature was raised to 82℃ and the reaction time was 2.5h; in step 5, the amount of wetting and dispersing agent DISPERBYK-110 was 9g, the amount of zirconium(IV) 2-ethylhexanoate mineral oil solution was 7g, the amount of cobalt(II) 2-ethylhexanoate mineral oil solution was 2.5g, and the amount of calcium 2-ethylhexanoate was 2.5g. All other conditions were the same as in Example 1.

[0047] Comparative Example 1:

[0048] The difference from Example 1 is that step 1 is omitted, and the 520g of epoxidized tung oil added in step 2 is replaced with tung oil that has been dehydrated and volatilized under reduced pressure at 60℃ and 5kPa and whose mass is controlled to be 520g; the other conditions are the same as in Example 1.

[0049] Comparative Example 2:

[0050] The difference from Example 1 is that in step 2, after adding 3-aminopropyltriethoxysilane, the temperature was not raised to 70°C and stirred for 4 hours under nitrogen protection. Instead, the mixture was stirred at 25°C and 500 rpm for 10 minutes and then the butyl acetate was removed under reduced pressure and the removal was controlled to a system mass of 570 g. The other conditions were the same as in Example 1.

[0051] Comparative Example 3:

[0052] The difference from Example 1 is that the amount of tetraethoxysilane used in step 3 is 0g; the other conditions are the same as in Example 1.

[0053] Comparative Example 4:

[0054] The difference from Example 1 is that the amount of tetraisopropyl titanate used in step 3 is 0g; the other conditions are the same as in Example 1.

[0055] Comparative Example 5:

[0056] The difference from Example 1 is that step 4 is omitted, and the 40g of core-shell far-infrared nano-ceramic powder added in step 5 is replaced with 40g of far-infrared nano-ceramic powder; the other conditions are the same as in Example 1.

[0057] Comparative Example 6:

[0058] The difference from Example 1 is that in step 4, after the dopamine hydrochloride oxidative self-polymerization deposition is completed, 3g of branched polyethyleneimine (weight average molecular weight of about 25,000) is added and stirred for 1 hour, and then 2g of branched polyethyleneimine (weight average molecular weight of about 800) is added and stirred for 4 hours; the other conditions are the same as in Example 1.

[0059] Comparative Example 7:

[0060] The difference from Example 1 is that in step 4, branched polyethyleneimine (weight average molecular weight of about 800) is replaced with branched polyethyleneimine (weight average molecular weight of about 25,000); the other conditions are the same as in Example 1.

[0061] Performance testing:

[0062] Sample preparation: Far-infrared paint for flooring was prepared according to Examples 1-5 and Comparative Examples 1-7, and coating test boards were prepared on the same batch of wood flooring to be coated according to step 6 of each example. The test board size was 150mm×70mm×(original thickness of wood flooring), and 3 test boards were prepared for each sample. After coating, the boards were placed at (25±1)℃ and (50±5)% relative humidity for 7 days before testing. Except for the far-infrared temperature rise test, all other tests were completed at (23±2)℃ and (50±5)% relative humidity.

[0063] Far-infrared emissivity test: The far-infrared emissivity test was conducted in accordance with GB / T 30127-2013. This invention applies the method to the coating test plate, and performs the test according to its temperature control / wavelength conditions, as an evaluation method for far-infrared performance. The coating test plates of Examples 1-5 and Comparative Examples 1-7 were tested respectively. The test plate was cut into 50mm×50mm pieces and the surface was ensured to be flat and free of contamination. The sample and the standard blackbody plate were placed on a hot plate at the same time. The surface temperature of the hot plate was adjusted so that the temperature of both the sample and the standard blackbody plate reached (34±0.1)℃. The effective emissivity of the standard blackbody plate was not less than 0.96. The detection wavelength range of the far-infrared detection instrument was 5-14μm. After the temperature of the sample and the blackbody plate stabilized, the far-infrared radiation intensity I of the sample and the far-infrared radiation intensity I0 of the standard blackbody plate were measured respectively. The far-infrared emissivity η was calculated according to η=I / I0. The average value of each sample was taken after three consecutive tests and retained to 0.01.

[0064] Far-infrared irradiation temperature rise test: The far-infrared irradiation temperature rise test was conducted according to GB / T 30127-2013. This invention applies this method to the coating test panel, performing the test under its temperature / wavelength control conditions, as an evaluation method for far-infrared performance. The present invention applies this method to coating test plates, performing it according to their temperature control / wavelength conditions, as an evaluation method for far-infrared performance. Tests are conducted on coating test plates of Examples 1-5 and Comparative Examples 1-7 respectively. The test plates are cut to 50mm × 50mm, and a temperature sensor is fixed at the center of the back of the sample. The distance between the sample and the radiation source is adjusted so that the distance from the sample surface to the radiation source is 500mm. The initial surface temperature T0 of the sample is recorded. The far-infrared radiation source is turned on and irradiated for 30s. The surface temperature T of the sample after 30s of irradiation is recorded. The temperature rise ΔT is calculated according to ΔT = T - T0. The test is repeated 3 times, and the average value is retained to 0.1℃.

[0065] Film hardness: The pencil hardness of the coating was tested according to GB / T 6739-2022. The test plates were the coating test plates prepared in step 6 and cured for 7 days in Examples 1-5 and Comparative Examples 1-7. Before the test, the coating surface was cleaned with a soft cloth, the pencil was sharpened according to the standard method and the end face was smoothed on 400 grit sandpaper. The test load was 750g, the test angle was 45°, and the scratch length was 6mm. Each test plate was tested 5 times at different locations. The highest hardness level without visible scratches was recorded. The mode of the 3 test plates was taken as the result of the sample.

[0066] Abrasion resistance: The abrasion resistance of the coating was tested according to GB / T 1768-2006. The test plates were the coatings prepared in step 6 and cured for 7 days in Examples 1-5 and Comparative Examples 1-7. A Taber abrasion tester was used with a CS-10 grinding wheel, a load of 1000g / wheel, a rotation speed of 60rpm, and 1000 cycles. The mass of the test plate was weighed before and after the test with an accuracy of 0.1mg. The mass loss Δm (mg / 1000cycles) was calculated. Three test plates were tested for each sample, and the average value was taken and retained to 1mg.

[0067] Water resistance: The water resistance of the coating film was tested according to GB / T 1733-1993. The test panels were the coating test panels prepared in step 6 and cured for 7 days in Examples 1-5 and Comparative Examples 1-7. The test panels were placed horizontally with the coating side facing up and immersed in deionized water at (23±2)℃, with the water level 30 mm above the surface of the test panel, for 168 h. After being taken out, the surface moisture was gently wiped with filter paper and placed at (23±2)℃ for 2 h. Changes such as blistering, whitening, wrinkling, and peeling of the coating film were observed and the results were recorded.

[0068] Storage stability and viscosity change: Storage stability tests were conducted according to GB / T 6753.3-1986. The samples were paint samples obtained from Examples 1-5 and Comparative Examples 1-7, placed in sealed containers of the same specifications, and placed in a constant temperature chamber at (50±1)℃ for 7 days. After that, they were taken out and placed at (23±2)℃ for 24 hours. The viscosity (outflow time, s) before and after storage was measured using a Forte 4 viscometer according to GB / T 1723-1993. The viscosity change Δt (s) and sedimentation height h (mm) were recorded. The test results are shown in Table 1.

[0069] Table 1 Performance test results of the examples and comparative examples

[0070] Sample Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 η (5-14μm) 0.9 0.91 0.93 0.92 0.94 0.88 0.86 0.89 0.88 0.88 0.88 0.87 ΔT (°C) 2 2.2 2.5 2.3 2.6 1.7 1.5 1.9 1.8 1.8 1.8 1.6 Pencil hardness (H) 2H 2H 3H 3H 3H H H H H 2H 2H H Δm (mg / 1000 cycles) 34 28 20 22 24 48 55 41 43 46 40 50 Water resistance (168h) Slight whitening, recovered after 2 hours No abnormalities No abnormalities No abnormalities Slight whitening, recovered after 2 hours Slight whitening, recovered after 2 hours Bubbling, turning white Slightly white Slightly white Bubbling, slightly white Slight whitening, recovered after 2 hours Bubbling, turning white Δt(s) 2 3 3 4 6 6 10 6 5 9 8 12 h (mm) 1 1 2 2 3 4 6 4 4 7 6 8

[0071] Data Analysis:

[0072] As can be seen from the data in Table 1, the far-infrared paint for flooring prepared by this invention maintains a high level in far-infrared emission and irradiation heating, while also achieving high pencil hardness and low abrasion. It is resistant to blistering and peeling after water immersion and exhibits minimal viscosity change and sedimentation during storage. This may be because the reactive sites introduced by epoxidized tung oil facilitate the grafting and fixation of 3-aminopropyltriethoxysilane, which, under the subsequent hydrolytic condensation of tetraethoxysilane and tetraisopropyl titanate, constructs a dense organic-inorganic hybrid network. This network, on the one hand, improves the cohesive strength and abrasion resistance of the coating film, and on the other hand, provides interfacial anchoring for the uniform dispersion of modified far-infrared nano-ceramic powder, reducing micro-defects and water penetration channels caused by agglomeration. Furthermore, the surface layer composed of polydopamine, branched polyethyleneimine, and tannic acid enhances the interaction between the far-infrared nano-ceramic powder and the resin matrix, simultaneously improving far-infrared functionality and mechanical / water-resistant properties, demonstrating a synergistic effect.

[0073] As can be seen from the data in Table 1 for Example 1 and Comparative Example 1, Comparative Example 1 showed a decline in far-infrared emission and irradiation heating performance, with simultaneous deterioration in abrasion resistance and water resistance. Viscosity fluctuations and sedimentation were also more pronounced after storage. The main reason for this is likely that Comparative Example 1 did not undergo epoxidation treatment, resulting in insufficient reactive sites on the tung oil backbone. This made it more difficult to effectively graft and fix 3-aminopropyltriethoxysilane, hindering the subsequent condensation crosslinking with tetraethoxysilane and tetraisopropyl titanate. Insufficient interfacial bonding weakens the dispersion stability of the modified far-infrared nano-ceramic powder, leading to localized agglomeration and increased porosity. This weakens effective far-infrared radiation and provides channels for moisture penetration and abrasion damage.

[0074] As can be seen from the data in Table 1 for Example 1 and Comparative Example 2, Comparative Example 2 showed significant deterioration in far-infrared performance, water resistance, abrasion resistance, and storage stability. It was more prone to foaming and whitening after water immersion, and exhibited increased viscosity changes and sedimentation tendency. This may be because Comparative Example 2 did not undergo grafting and reaction under nitrogen protection; instead, 3-aminopropyltriethoxysilane, tetraisopropyl titanate, and tetraethoxysilane were introduced only through physical mixing. The silanes lacked a stable chemical bond with the resin. Unfixed small molecules easily migrated and induced micro-defects, while the far-infrared nano-ceramic powder particles were difficult to encapsulate by the hybrid network, leading to increased agglomeration and simultaneous damage to both far-infrared performance and durability protection.

[0075] As can be seen from the data in Table 1 for Example 1 and Comparative Examples 3 and 4, when tetraethoxysilane or tetraisopropyl titanate is missing, the far-infrared performance, hardness, and overall wear and water resistance of the coating film all decrease to varying degrees, and the storage stability also deteriorates. This may be because tetraethoxysilane mainly contributes to the silicon-oxygen crosslinking structure, while tetraisopropyl titanate mainly contributes to the titanium-oxygen crosslinking structure. Both contribute to improving network density and interfacial anchoring strength during hydrolysis and polycondensation. When one of them is missing, the density and continuity of the hybrid network crosslinking points decrease, resulting in insufficient interfacial fixation of the modified far-infrared nano-ceramic powder. This easily leads to local enrichment and micropores, thereby simultaneously weakening both effective far-infrared radiation and water / wear resistance, demonstrating that the synergistic polycondensation of the two precursors results in a 1+1 greater than 2 effect.

[0076] As can be seen from the data in Example 1 and Comparative Example 5 in Table 1, when the far-infrared nano-ceramic powder is used directly without surface construction with polydopamine, branched polyethyleneimine, and tannic acid, the sedimentation and viscosity fluctuations after storage increase, and the water resistance and wear resistance are more easily deteriorated, making it difficult to maintain stable far-infrared performance. This may be because the unmodified far-infrared nano-ceramic powder has a high surface energy, making it prone to agglomeration and sedimentation in the resin system, leading to particle-rich areas and interface defects within the coating film. These defects not only reduce the effective far-infrared radiation area but also evolve into water seepage channels and stress concentration points under immersion and abrasion, simultaneously impairing both mechanical properties and durability.

[0077] As can be seen from the data in Table 1 for Example 1 and Comparative Examples 6 and 7, changes in the order of addition and molecular weight of branched polyethyleneimine exacerbated the sedimentation and viscosity changes in the system, further affecting far-infrared performance and water and abrasion resistance. This may be because branched polyethyleneimine plays a decisive role in the density and interfacial interaction of the polydopamine deposition layer: improper addition order easily leads to discontinuous coating, while excessively large molecular weight easily causes bridging flocculation and increased viscosity. When particles shift from stable dispersion to flocculation and aggregation, the uniformity of the coating microstructure decreases, the far-infrared functional layer is difficult to spread continuously, and moisture is more likely to penetrate along interfacial defects.

[0078] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A far-infrared paint for flooring, characterized in that, The product comprises, by weight, the following raw materials: 520 parts of the far-infrared organic-inorganic hybrid tung oil resin, 30-60 parts of the core-shell far-infrared nano-ceramic powder, 200 parts of butyl acetate, 80-120 parts of ethyl acetate, 40-60 parts of 2-propanol, 40-70 parts of isoparaffin solvent oil, 6-10 parts of wetting and dispersing agent, 8-15 parts of wear-resistant wax powder, 2-3 parts of cobalt(II) 2-ethylhexanoate mineral oil solution, 5-7 parts of zirconium(IV) 2-ethylhexanoate mineral oil solution, 2-3 parts of calcium 2-ethylhexanoate, and 3-4 parts of 2-butanone oxime; The core-shell far-infrared nano-ceramic powder includes a far-infrared nano-ceramic powder core and a shell layer covering the surface of the far-infrared nano-ceramic powder core. The shell layer is composed of a polydopamine deposition layer formed by dopamine oxidation self-polymerization, a branched polyethyleneimine layer, and a tannic acid layer. The branched polyethyleneimine layer includes branched polyethyleneimine with a weight average molecular weight of 600-1000 and branched polyethyleneimine with a weight average molecular weight of 20000-30000. The far-infrared nano-ceramic powder is titanium dioxide with an average particle size of 15-25 nm. The far-infrared organic-inorganic hybrid tung oil resin comprises tung oil organic segments and an organic-inorganic hybrid network containing Si-O-Si bonds and Si-O-Ti bonds. The far-infrared organic-inorganic hybrid tung oil resin is obtained by reacting epoxidized tung oil with 3-aminopropyltriethoxysilane to obtain silane-grafted epoxidized tung oil, which is then further hydrolyzed and condensed with tetraethoxysilane and tetraisopropyl titanate.

2. The far-infrared paint for flooring according to claim 1, characterized in that, It also includes 4 parts rheology modifier, 3 parts leveling agent and 3 parts defoamer.

3. The far-infrared paint for flooring according to claim 2, characterized in that, The rheology modifier is RHEOBYK-410, the leveling agent is BYK-333, and the defoamer is BYK-054.

4. The far-infrared paint for flooring according to claim 1, characterized in that, The wetting and dispersing agent is DISPERBYK-110; the abrasion-resistant wax powder is CERAFLOUR1050.

5. The far-infrared paint for flooring according to claim 1, characterized in that, In the raw materials for preparing the core-shell far-infrared nano-ceramic powder, the mass ratio of far-infrared nano-ceramic powder core, dopamine, branched polyethyleneimine with a weight average molecular weight of 600-1000, branched polyethyleneimine with a weight average molecular weight of 20000-30000, and tannic acid is 30-60:3-6:1-3:2-5:3-6.

6. The far-infrared paint for flooring according to claim 1, characterized in that, In the raw materials for preparing the far-infrared organic-inorganic hybrid tung oil resin, the mass ratio of epoxidized tung oil, 3-aminopropyltriethoxysilane, tetraisopropyl titanate and tetraethoxysilane is 520:60-110:20-45:25-70.

7. The far-infrared paint for flooring according to claim 1, characterized in that, The epoxidized tung oil is obtained by epoxidizing the unsaturated double bonds of tung oil with performic acid generated in situ from formic acid and hydrogen peroxide, thereby introducing epoxidation reaction sites.

8. A method for preparing far-infrared paint for flooring according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Tung oil is epoxidized to obtain epoxidized tung oil; (2) The epoxidized tung oil is grafted with 3-aminopropyltriethoxysilane to obtain silane-grafted epoxidized tung oil; (3) The silane-grafted epoxidized tung oil is hydrolyzed and polycondensed with tetraethoxysilane and tetraisopropyl titanate to obtain far-infrared organic-inorganic hybrid tung oil resin. (4) Using far-infrared nano-ceramic powder as the core, core-shell far-infrared nano-ceramic powder is obtained by dopamine oxidation self-polymerization deposition and combined with branched polyethyleneimine and tannic acid surface modification. (5) The far-infrared organic-inorganic hybrid tung oil resin obtained in step (3) and the core-shell far-infrared nano-ceramic powder obtained in step (4) are mixed and dispersed in a solvent to obtain far-infrared paint for flooring.

9. The method for preparing far-infrared paint for flooring according to claim 8, characterized in that, Step (4) includes: adding deionized water and sodium bicarbonate to the reaction vessel and stirring to dissolve them; adding far-infrared nano-ceramic powder and dispersing it to form a slurry; adding dopamine hydrochloride and stirring in an open container for 2 hours to allow it to oxidize and self-polymerize and deposit on the surface of the far-infrared nano-ceramic powder; then adding branched polyethyleneimine with a weight average molecular weight of 800 and stirring for another 4 hours; filtering, separating, washing and drying to constant weight; then adding deionized water and 2-propanol and dispersing for 10 minutes; adding 2-5 parts of branched polyethyleneimine with a weight average molecular weight of 25000 and stirring for 1 hour; dissolving tannic acid in deionized water and adding it to the mixture and stirring for another 1 hour; then filtering, separating, washing and drying to constant weight to obtain core-shell far-infrared nano-ceramic powder.

10. The method for preparing far-infrared paint for flooring according to claim 8, characterized in that, Step (5) includes: adding butyl acetate and wetting and dispersing agent to a dispersion tank, adding core-shell far-infrared nano-ceramic powder under stirring and dispersing at 2000 rpm for 30 min; adding far-infrared organic-inorganic hybrid tung oil resin and butyl acetate at 500 rpm and stirring for 20 min; then adding ethyl acetate, 2-propanol and isoparaffin solvent oil and stirring for 10 min; subsequently adding rheology modifier and wear-resistant wax powder and stirring for 20 min, adding leveling agent and defoamer and stirring for 10 min, adding cobalt(II) 2-ethylhexanoate mineral oil solution, zirconium(IV) 2-ethylhexanoate mineral oil solution, calcium 2-ethylhexanoate and 2-butanone oxime and stirring for 10 min, and filtering through 100 mesh to obtain far-infrared paint for flooring.