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CN-118580739-B - PGL-based bio-based flame retardant coating and preparation method and application thereof

CN118580739BCN 118580739 BCN118580739 BCN 118580739BCN-118580739-B

Abstract

The invention discloses a bio-based flame retardant coating based on PGL, which takes urea and formaldehyde as main raw materials, takes a silane coupling agent KH550 as an auxiliary agent, takes phytic acid-guanazole-lignin composite polymer PGL as a bio-based flame retardant, takes ammonium chloride as a curing agent, has the decomposition temperature of 231.9+/-5 ℃ when the decomposition mass is 5%, has the temperature of 284.5+/-5 ℃ when the maximum decomposition rate is reached, and has the carbon residue amount of 35.3+/-2 wt.% when the decomposition mass is 800 ℃. The preparation method comprises the following steps of 1, preparing phytic acid-guanazole-lignin composite polymer PGL, 2, preparing modified urea resin emulsion MUF, and 3, preparing the bio-based flame retardant coating PGL/MUF based on the PGL. When the flame retardant coating is used as a flame retardant coating for wood, the flame retardant coating has flame retardant property, passes the UL-94V-0 grade test in the UL-94 grade test, is continuous and compact in carbon residue carbon layer after combustion, has a limiting oxygen index of 36.5+/-1%, has a maximum heat release rate of 19.19 +/-1.29 kW/m 2 , has a total heat release amount of 1.20+/-0.05 MJ/m 2 , and has a fire disaster growth index of 0.27+/-0.05 kW/m 2 /s.

Inventors

  • ZOU YONGJIN
  • WEI AN
  • XIANG CUILI
  • Lu Xulan
  • WANG SHUNXIANG
  • XU FEN
  • SUN LIXIAN

Assignees

  • 桂林电子科技大学

Dates

Publication Date
20260505
Application Date
20240613

Claims (8)

  1. 1. The preparation method of the bio-based flame retardant coating based on PGL is characterized by comprising the following steps: step 1, preparing phytic acid-guanazole-lignin composite polymer PGL, and stirring formaldehyde solution, guanazole GZ, lignin LIG and phytic acid PA solution for reaction to prepare phytic acid-guanazole-lignin composite polymer PGL; The stirring reaction in the step 1 is divided into two steps, Firstly, adding a first-stage formaldehyde solution into deionized water to obtain a solution A, then adding GZ into the solution A to obtain a solution B, and stirring for reaction after the addition is finished to obtain a solution C; Firstly, adding LIG into a solution C obtained in the step 1.1 to obtain a solution D, then adding a formaldehyde solution in a second stage into the solution D to obtain a solution E, then adding a PA solution with the mass fraction of 70 wt% into the solution E to obtain a solution F, stirring the solution F for reaction, filtering the obtained product after the stirring reaction is finished, repeatedly washing with deionized water, and then drying and grinding filter residues to obtain the phytic acid-guanazole-lignin composite polymer PGL; step 2, preparing modified urea-formaldehyde resin emulsion MUF, namely firstly adding sodium hydroxide solution into formaldehyde solution to adjust the pH value of the solution to obtain solution G, then heating the solution G, and finally adding urea, silane coupling agent KH550, PGL obtained in the step 1, acetic acid solution and sodium hydroxide solution into the solution G to perform stirring reaction to prepare modified urea-formaldehyde resin emulsion MUF; the stirring reaction in the step 2 is divided into three steps, Step 2.1, under a certain temperature condition, firstly, adding urea in a first stage into a solution G to obtain a solution H, then adding a silane coupling agent KH550 into the solution H, and continuously stirring to obtain a solution I; Step 2.2, under a certain temperature condition, firstly adding an acetic acid solution into the solution I to adjust the pH value of the solution to obtain a solution J, then adding urea in a second stage into the solution J to obtain a solution K, and finally adding PGL obtained in the step 1 into the solution K, and continuing stirring until reaching a reaction end point to obtain a solution L; Step 2.3, under a certain temperature condition, firstly adding sodium hydroxide solution into the solution L to adjust the pH value of the solution to obtain solution M, then adding urea in a third stage into the solution M, adjusting the temperature, and stirring the solution M to obtain MUF; Step 3, preparing the bio-based flame retardant coating based on PGL, namely adding ammonium chloride into the MUF obtained in the step 2 to obtain a solution N according to a certain mass ratio of MUF to ammonium chloride, and stirring to uniformly mix the components to obtain the bio-based flame retardant coating based on PGL; In the step 1 and the step 2, the mass fraction of the formaldehyde solution is 37 wt percent; in the step 2, the mass fractions of the sodium hydroxide solution are 20 wt%; In the step 2.2, the mass fraction of the acetic acid solution is 20 wt%.
  2. 2. The method according to claim 1, wherein in the step 1, the mass ratio of the total mass of the formaldehyde solution, GZ, deionized water, LIG and PA is 17.6:13.2:300:8.7:21; in the step1, the addition amount of the formaldehyde solution in the two stages satisfies the mass ratio of 6.6:11; In the step 2, the mass ratio of the formaldehyde solution to the urea to KH550 to PGL is 100:57:5.7:2.85; in the step 2, the urea addition amount in the three stages satisfies the mass ratio of 37:12.4:7.6; in the step 3, the mass ratio of MUF to ammonium chloride is 100:1.
  3. 3. The method according to claim 1, wherein the stirring reaction condition in the step1 is that the stirring temperature is 80 ℃ and the stirring rotation speed is 400 rpm; in the step 1.1, stirring and reacting for 1 h hours; In the stirring reaction of the step 1.1, the solution B is changed from clear to turbid, and then the step 1.1 is completed after the solution B is changed from turbid to clear; In the step 1.2, the stirring reaction time is 5h; In the step 1.2, the washing condition is that the pH value of the washing liquid is between 4.0 and 5.0, the drying temperature is between 60 and 80 ℃ and the drying time is between 24 and 48 h.
  4. 4. The preparation method according to claim 1, wherein in the step 2, a sodium hydroxide solution is added to adjust the pH of the formaldehyde solution to 8.0-8.5, In the step 2, the temperature of the solution G is raised to 90 ℃ under the condition that the stirring rotation speed is 400 rpm; the temperature condition in the step 2.1 is 90 ℃, and after the addition of the silane coupling agent KH550 is finished, the stirring is continued with the stirring time of 30 min; the temperature condition in the step 2.2 is 90 ℃, the pH value of the solution is adjusted to be 4.5-5.0 by adding acetic acid solution, and the stirring time is 10-15 min after the addition of PGL is finished, so that the reaction is ensured to reach the end point; In the step 2.2, the judgment sign of the reaction end point is that after the solution L is dripped into water under the condition that the water temperature is 30 ℃, the solution L is in a colloid shape which is insoluble in water as a whole; the temperature condition in the step 2.3 is 90 ℃, the pH value of the solution is adjusted to 7.5-8.0 by adding sodium hydroxide solution, and the stirring condition is that the stirring temperature is 70 ℃ and the stirring time is 30min after the urea is added.
  5. 5. The method of claim 1, wherein in step 3, the stirring condition after the addition of ammonium chloride is performed is a stirring speed of 500-600 rpm and a stirring time of 1-1.5-h.
  6. 6. The method of claim 2, wherein the PGL-based bio-based flame retardant coating has flame retardant properties when applied as a flame retardant coating for wood, and the flame retardant coated wood passes the UL-94 grade test V-0, and the expanded carbon residue layer formed on the burned surface of the flame retardant coated wood exhibits continuous and dense properties.
  7. 7. The method of claim 2, wherein the final oxygen index of the PGL-based bio-based flame retardant coating is 36.5.+ -. 1% in the final oxygen index test of the wood coated with the flame retardant coating.
  8. 8. The method of claim 2, wherein the obtained PGL-based bio-based flame retardant coating is applied as a flame retardant coating for wood, and the wood coated with the flame retardant coating has a maximum heat release rate of 19.19.+ -. 1.29 kW/m 2 , a total heat release of 1.20.+ -. 0.05 MJ/m 2 , and a fire growth index of 0.27.+ -. 0.05 kW/m 2 /s in a cone calorimetric test.

Description

PGL-based bio-based flame retardant coating and preparation method and application thereof Technical Field The invention relates to the field of flame-retardant materials, in particular to a bio-based flame-retardant coating based on PGL, and a preparation method and application thereof. Background As a material with rich resources, green and renewable performance and high processability, the wood is widely applied to the fields of buildings, furniture and the like and is closely related to the life of people. However, wood itself has flammable properties, and fires due to combustion of wood often occur. Therefore, the wood must be flame-retardant modified to improve its flame-retardant properties and reduce its fire hazard. For example, in the prior art document 1 (Innovative Polyelectrolyte Treatment to Flame-Retard Wood [ J ]. Polymers (Basel) 2021 13 (17)), the flame retardant property of Wood is greatly improved by depositing polyethyleneimine and sodium phytate polyelectrolyte on the surface of Wood. However, the technical scheme has the problem that the flame retardant can fall off in the long-term use process due to insufficient adhesion of the flame retardant on the surface, so that the flame retardant performance of the wood is reduced. In order to solve the technical problems, the flame retardant can be selectively permeated into the wood coating to prepare the wood flame retardant coating. The wood coating has good adhesion to the surface of the wood, and the flame retardant is coated on the wood after penetrating into the wood coating, so that the adhesion problem can be improved, and the effect of improving the flame retardant property of the wood can be achieved. For example, prior document 2("Epoxy-modified silicone resin based N/P/Si synergistic flame-retardant coating for wood surface"[J].Progress in Organic Coatings 170(2022)106953) forms an epoxy-modified Silicon (SiR) coating by condensing dimethyldiethoxysiloxane with 3-glycidoxypropyl trimethoxysilane (KH-560), and cures the resin with a nitrogen-phosphorus containing flame retardant (PTDP), the cured coating greatly improving the flame retardant properties of wood. However, the problem with this solution is that the non-bio-based flame retardant such as PTDP may not degrade in the environment due to poor biocompatibility during long-term use, resulting in accumulation in the environment and thus causing a certain damage to the environment. In order to solve the technical problems, a degradable and environment-friendly bio-based material is generally selected for preparing the flame retardant. For example, prior document 3("Synthesis of bio-based flame-retardant epoxy co-curing agent and application in wood surface coating"[J].Progress in Organic Coatings 167(2022)106848) synthesizes a novel bio-based flame retardant co-curing agent (PDD) by reacting Protocatechualdehyde (PH), 4 '-diaminodiphenyl ether (DDE) and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and obtains a flame retardant epoxy coating for wood after impregnating PDD and 4,4' -diaminodiphenyl methane (DDM) as co-curing agents into commercial epoxy resin, wherein the limiting oxygen index of the coated wood reaches 32.6%. The technical proposal has the problems that the PDD content of the bio-based flame retardant in the flame retardant coating exceeds 20wt.%, and the use cost of the flame retardant is greatly improved. In order to achieve the same flame retardant effect and reduce the addition amount of the flame retardant, in the earlier stage of the present inventors, the prior document 4 (a flame retardant coating based on a PA-MEL flame retardant curing agent, a preparation method and an application thereof, CN 117887324 a) can achieve the flame retardant and curing effects of the flame retardant coating at the same time by using phytic acid-melamine polyelectrolyte PM as a bio-based flame retardant curing agent of sodium lignin sulfonate modified urea resin, and when the addition amount of PM is only 2wt.%, the wood after the flame retardant coating is coated can achieve UL-94V-0 grade, and the limiting oxygen index reaches 32.1%. Subsequent studies have found that the carbon content of the flame retardant curing agent of this technical scheme is not sufficiently rich, resulting in a lower limiting oxygen index value, that is, there is room for further improvement in limiting oxygen index. Disclosure of Invention The invention aims to provide a bio-based flame retardant coating based on PGL, and a preparation method and application thereof. Aiming at the problems existing in the prior art, firstly, a biological-based flame retardant phytic acid-guanazole-lignin composite polymer PGL with high carbon-containing lignin groups is prepared by utilizing a Mannich reaction and a supermolecule self-assembly technology, is taken as a biological-based flame retardant component, is infiltrated into urea-formaldehyde resin modified by a silane coupling agent KH5