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CN-121975421-A - Paint for wood corrosion prevention and preparation method thereof

CN121975421ACN 121975421 ACN121975421 ACN 121975421ACN-121975421-A

Abstract

The invention relates to a paint for wood corrosion prevention and a preparation method thereof, belonging to the technical field of paint. The invention discloses a modified aqueous polyurethane which is synthesized autonomously as a film forming substance, the synthetic route is that an intermediate is prepared by hydrosilylation of hydrogen-terminated silicone oil and N-ethyl methyl acrylamide, then the intermediate is subjected to continuous substitution and quaternization reaction with 3-bromopropanol and methyl iodide to prepare a modifier with a dihydric alcohol structure, finally the modifier is copolymerized with dihydric alcohol, isocyanate and the like, and the modified aqueous polyurethane emulsion is neutralized and emulsified, the emulsion is matched with a functional auxiliary agent to prepare the paint for wood corrosion prevention, and hydrophobic organosilicon and antibacterial quaternary ammonium salt are cooperatively introduced into a polyurethane skeleton through chemical bonds.

Inventors

  • LI CHEN
  • ZHOU XIN
  • ZHU LIN

Assignees

  • 扬州工业职业技术学院

Dates

Publication Date
20260505
Application Date
20260323

Claims (9)

  1. 1. The wood preservative paint is characterized by comprising, by weight, 100 parts of modified aqueous polyurethane emulsion, 0.2-0.3 part of defoamer, 0.14-0.18 part of flatting agent and 0.55-0.7 part of thickener; Wherein, the modified aqueous polyurethane emulsion is prepared by the following method: a1, premixing hydrogen-terminated silicone oil, N-ethyl methacrylamide and anhydrous toluene, introducing nitrogen for protection, preheating to 50 ℃, slowly adding Karstedt catalyst for mixing, heating to 75-90 ℃ for continuous reaction for 4.5-5.5 hours, and obtaining an intermediate; A2, premixing an intermediate, triethylamine and anhydrous dioxane under the protection of dry nitrogen, heating to 65-75 ℃, slowly adding 3-bromopropanol, stirring for reaction for 4-5h, filtering, cooling to 40 ℃, adding methyl iodide and tetrabutylammonium bromide, and carrying out reflux reaction for 12-16h to obtain a modifier; And step A3, dissolving the modifier and ethyl acetate, mixing with polyethylene glycol, adding isophorone diisocyanate and dibutyltin dilaurate under the protection of dry nitrogen, uniformly mixing, heating to 80-90 ℃ for reaction for 2-2.5h, cooling to 50 ℃, adding dimethylolpropionic acid for chain extension reaction for 3.2-3.8h, neutralizing with triethylamine after the reaction is finished, and adding deionized water for emulsification to obtain the modified waterborne polyurethane emulsion.
  2. 2. The paint for wood preservation according to claim 1, wherein the hydrogen-terminated silicone oil has a silicon-hydrogen content, an amount ratio of N-ethylmethacrylamide to anhydrous toluene of 0.1mol:0.12-0.17mol:80-130mL, and a platinum content of the system after Karstedt catalyst addition of 20-30ppm.
  3. 3. A wood preservative paint according to claim 2, characterized in that the viscosity of the hydrogen terminated silicone oil is 20-50mm 2 /s.
  4. 4. A wood preservative paint according to claim 3, characterized in that the ratio of the intermediate, 3-bromopropanol, methyl iodide and anhydrous dioxane is 50g:0.08-0.11mol:0.15-0.2mol:260-330mL, the amount of triethylamine is 2.5-3.2wt% of the reaction system, and the amount of tetrabutylammonium bromide is 0.12-0.18wt% of the reaction system.
  5. 5. The wood preservative paint as claimed in claim 4, wherein the molar ratio of total isocyanate groups to hydroxyl groups of isophorone diisocyanate, polyethylene glycol and modifier is 1.25-1.5:1, the modifier is used in an amount of 25-37wt% of polyethylene glycol, and the dibutyltin dilaurate is 0.03-0.04wt% of the total amount of the three.
  6. 6. A wood preservative paint according to claim 5, wherein the polyethylene glycol has an average molecular weight of 400-600.
  7. 7. A wood preservative paint according to claim 6, characterized in that the modified aqueous polyurethane emulsion has a solids content of 30-35% by weight.
  8. 8. The method for preparing the wood preservative paint according to any one of claims 1 to 7, which is characterized in that a defoaming agent, a leveling agent and a modified aqueous polyurethane emulsion are mixed, a thickening agent is added to adjust the viscosity after the pre-defoaming treatment, and final defoaming is performed again to obtain the wood preservative paint.
  9. 9. The method for producing a paint for preservation of wood according to claim 8, wherein the viscosity of the paint for preservation of wood is-4 cups for 25-30s at room temperature.

Description

Paint for wood corrosion prevention and preparation method thereof Technical Field The invention belongs to the technical field of coatings, and particularly relates to a paint for wood corrosion prevention and a preparation method thereof. Background Wood is favored in the fields of furniture, interior decoration, artwork and the like by its natural texture, warm touch and excellent environmental protection characteristics. With the improvement of life quality and health and environmental protection requirements of people, the development trend of high-quality wood products is increasingly remarkable. However, wood, as a porous biomass material, is extremely susceptible to moisture attack, microbial (bacterial, mold) attachment and biodegradation, resulting in decay, deformation, color loss, and serious aesthetic impact and life-time. Therefore, effective surface coating and corrosion protection treatment of wood is important. Traditional wood anti-corrosion paint mainly comprises oil paint, nitrolacquer, water paint and other types. Although the paint film of the oil paint is plump and high in hardness, the oil paint contains a large amount of Volatile Organic Compounds (VOC) which are harmful to the environment and human health, the nitrolacquer is quick to dry but poor in environmental protection and weather resistance, the water paint takes water as a dispersion medium, the VOC content is extremely low, the development trend of green environmental protection is met, and the oil paint becomes the current main flow of research and application. Among them, the aqueous polyurethane (WPU) paint is widely regarded as an ideal film forming material for high-performance aqueous wood paint because of its excellent flexibility, abrasion resistance, high gloss and good chemical resistance of paint film. However, when the conventional aqueous polyurethane is applied to the environment with high humidity and easiness in breeding microorganisms, the conventional aqueous polyurethane still has obvious defects that 1) the water resistance is relatively insufficient, hydrophilic groups in a molecular chain of the aqueous polyurethane provide emulsion stability, and simultaneously, a solidified paint film is easy to swell when contacting moisture for a long time, so that the protective performance is reduced, and 2) the active corrosion resistance is lacking, namely the polyurethane does not have an antibacterial function and cannot inhibit the colonization and growth of mold and bacteria on the surface of the paint film, and microbial metabolites can erode the paint film and destroy wood to cause biological corrosion. In order to remedy the defects, the prior art mainly adopts two schemes, namely, firstly, an antibacterial agent is physically added, although the method can endow a paint film with certain antibacterial property, the method has serious defects that a) the surface quality is degraded, small molecular antibacterial agent is easy to migrate to the surface from the inside of the paint film and separate out, so that a 'frosting' phenomenon is caused, the transparency and the luster of the paint film are affected, b) the durability is poor, the antibacterial agent can be rapidly consumed along with migration and use, the antibacterial efficacy is rapidly attenuated, and c) the safety and stability risks are that part of the antibacterial agent has environmental toxicity and possibly interacts with other components in the paint, so that the emulsion storage stability and the paint film performance are affected. And secondly, introducing organic silicon for modification. Polysiloxane chain segments are introduced into a polyurethane main chain through copolymerization or blending, and excellent hydrophobicity, flexibility and thermal stability of organosilicon are utilized to improve the water resistance, heat resistance and hand feeling of a paint film. However, this technology is challenged under aqueous systems by a) emulsion instability, poor compatibility of the strongly hydrophobic organosilicon segments with the hydrophilic polyurethane segments, extremely easy phase separation during emulsification and storage, resulting in emulsion breaking, delamination or coarsening of the particles, b) negative effects on the paint film properties, i.e. excessive organosilicon can significantly reduce the surface energy and cohesion of the paint film, resulting in reduced paint film adhesion, hardness loss and poor recoatability (poor interlayer adhesion). The mechanism is that the organosilicon chain segment can spontaneously migrate and concentrate to a paint film-air interface in the film forming process, a layer of soft shell with low surface energy is formed on the surface, and the intermolecular acting force between the paint film and the substrate and between the paint film layers is weakened although hydrophobicity is brought. In summary, developing an environment-friendly wood anti-corrosion paint which not