阅读说明：本技术 共聚制备脲类化合物改性蜜胺纤维的方法 (Method for preparing urea compound modified melamine fiber by copolymerization ) 是由 焦明立 李洁 杨凯 贾万顺 张啸梅 刘�英 于 2019-11-27 设计创作，主要内容包括：本发明公开了一种共聚制备脲类化合物改性蜜胺纤维的方法,在两份高分子水溶液中分别加入三聚氰胺和醛类,脲类化合物和醛类,再分别加入碱性催化剂反应不同时间；混合后加入碱性催化剂继续反应,湿法纺丝、加热固化得到改性蜜胺纤维。本发明通过湿法纺丝制备了改性蜜胺纤维,该纤维作为三维交联型纤维,具有阻燃、隔热、无融滴,燃烧低烟无毒、成本低、合成简单等优点。(The invention discloses a method for preparing urea compound modified melamine fiber by copolymerization, which comprises the steps of respectively adding melamine and aldehyde into two parts of high polymer aqueous solution, and respectively adding an alkaline catalyst for reaction for different times; and adding an alkaline catalyst after mixing to continue reacting, and carrying out wet spinning and heating curing to obtain the modified melamine fiber. The modified melamine fiber is prepared by wet spinning, and has the advantages of flame retardance, heat insulation, no melt drop, low smoke and no toxicity in combustion, low cost, simple synthesis and the like as the three-dimensional crosslinking fiber.)

1. A method for preparing urea compound modified melamine fiber by copolymerization is characterized by comprising the following steps:

(1) dissolving water-soluble polymer in water, dividing the water-soluble polymer into two parts, namely solution A and solution B, adding melamine, aldehyde compounds and an alkaline catalyst into the solution A, and reacting for a period of time at 50-95 ℃ to obtain solution A;

(2) adding urea compounds, aldehyde compounds and alkaline catalysts into the solution B, and reacting for a period of time at 45-95 ℃ to obtain a solution B;

(3) after the solution A and the solution B are mixed, an alkaline catalyst is used for adjusting the pH value to alkaline conditions, and the solution A and the solution B continue to react for a period of time at the temperature of 40-95 ℃ to obtain modified melamine resin spinning solution;

(4) and carrying out wet spinning, drying and winding on the modified melamine resin spinning solution to obtain nascent fiber, and then heating and curing in an oven at a certain heating rate to obtain the modified melamine fiber.

2. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: the water-soluble polymer in the step (1) is one of PVA, PEG, polyvinyl formal, PVP, water-soluble modified starch or water-soluble modified cellulose.

3. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: the aldehyde compound is one of formaldehyde, glutaraldehyde, acetaldehyde and paraformaldehyde; the alkaline catalyst is one of sodium hydroxide, potassium hydroxide, triethanolamine, sodium bicarbonate, magnesium hydroxide or calcium hydroxide.

4. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: in the step (1), the mass content of the polymer in the water-soluble polymer solution is 3-19%, and the molar ratio of melamine to aldehyde (based on the mass of the aldehyde-containing substance) is 1: 0.7-5, wherein the mass ratio of the water-soluble polymer to the melamine is 1: 0.1 to 10, the pH value range of the solution A is 7.4 to 11, and the reaction time is 0.4 to 10 hours.

5. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: in the step (2), the urea compound is one of urea, biuret and phenylurea.

6. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: in the step (2), the molar ratio of the urea compound to the aldehyde (based on the amount of the aldehyde group-containing substance) is 1: 0.7-4, wherein the mass ratio of the water-soluble polymer to the urea compound is 1: 0.1 to 9, the pH value range of the solution B is 7.5 to 10.5, and the reaction time is 0.5 to 8 hours.

7. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: the pH value range of the solution in the step (3) under the alkaline condition is 7.4-10.5, and the reaction time is 0.4-8 h.

8. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: and (3) adding 0.01-0.9 wt% of boric acid into the coagulation bath of the wet spinning in the step (4), wherein the temperature of the coagulation bath is 30-60 ℃, the drying temperature is 60-130 ℃, and the winding speed is 10-500 m/min.

9. The method for preparing the urea compound-modified melamine fiber by copolymerization according to claim 1, wherein: and (4) heating and curing at the heating rate of 1-20 ℃/min to 150-200 ℃, keeping the temperature for 0.1-2h, and naturally cooling and taking out to obtain the modified melamine fiber.

Technical Field

The invention belongs to the field of preparation of special fibers, and particularly relates to a method for preparing urea compound modified melamine fibers by copolymerization and a preparation method for obtaining the modified melamine fibers by wet spinning and thermosetting.

Background

The melamine resin fiber is a novel high-temperature resistant flame-retardant fiber, which is not melted, does not drip, basically does not shrink or shrinks very little when meeting fire, has a limit oxygen index higher than 30, and has a thermal decomposition temperature of about 400 ℃ (Hepeng, Qilu. Melamine is inexpensive and has been widely used in some high temperature applications. However, melamine has disadvantages of high functionality and high crosslinking degree, and is not easy to synthesize or the resin has a short shelf life after synthesis, which hinders the preparation of melamine fiber, and how to further improve the performance of melamine fiber becomes a research focus.

Urea, which is one of urea compounds, can react with formaldehyde under the action of an alkaline catalyst to be condensed into urea-formaldehyde resin and has flame retardance. The cured urea-formaldehyde resin has light glue line color, no pollution to the adhered material, good processing property, lower cost than other synthetic resin adhesives, excellent adhesion property, better water resistance and other advantages [ mu Ying, development of low-temperature cured low-toxicity urea-formaldehyde resin adhesive [ D ]. Fujian agriculture and forestry university, 2008 ]. The patent provides a method for preparing urea compound modified melamine fiber by combining the advantages of urea-formaldehyde resin and melamine resin.

Disclosure of Invention

The invention aims to provide a method for preparing urea compound modified melamine fiber by copolymerization, which comprises the steps of respectively adding melamine, urea compound and aldehyde compound into a high molecular aqueous solution, reacting, blending, adjusting to alkaline condition, reacting to obtain spinning solution, and preparing three-dimensional crosslinked modified melamine fiber by wet spinning and thermosetting. The method provides a method for preparing the urea compound modified melamine fiber by copolymerization.

The technical scheme of the invention is as follows: a method for preparing urea compound modified melamine fiber by copolymerization comprises the following steps:

(1) dissolving water-soluble polymer in water, dividing into two parts, one part is solution A and the other part is solution B, adding melamine, aldehyde compound and alkaline catalyst into solution A, and reacting at 50-95 deg.C for a period of time to obtain solution A (melamine solution with small molecular weight);

(2) adding urea compounds, aldehyde compounds and alkaline catalysts into the solution B, and reacting for a period of time at 45-95 ℃ to obtain a solution B;

(3) after the solution A and the solution B are mixed, an alkaline catalyst is used for adjusting the pH value to alkaline conditions, and the solution A and the solution B continue to react for a period of time at the temperature of 40-95 ℃ to obtain modified melamine resin spinning solution;

(4) and carrying out wet spinning, drying and winding on the modified melamine resin spinning solution to obtain nascent fiber, and then heating and curing in an oven at a certain heating rate to obtain the modified melamine fiber.

Further, the water-soluble polymer in the step (1) is one of PVA, PEG, polyvinyl formal, PVP, water-soluble modified starch or water-soluble modified cellulose.

Further, the aldehyde compound is one of formaldehyde, glutaraldehyde, acetaldehyde and paraformaldehyde; the alkaline catalyst is one of sodium hydroxide, potassium hydroxide, triethanolamine, sodium bicarbonate, magnesium hydroxide or calcium hydroxide.

Further, in the step (1), the mass content of the polymer in the water-soluble polymer solution is 3-19%, and the molar ratio of melamine to aldehyde (based on the mass of the aldehyde-containing substance) is 1: 0.7-5, wherein the mass ratio of the water-soluble polymer to the melamine is 1: 0.1 to 10, the pH value range of the solution A is 7.4 to 11, and the reaction time is 0.4 to 10 hours.

Further, in the step (2), the urea compound is one of urea, biuret and phenylurea.

Further, in the step (2), the molar ratio of the urea compound to the aldehyde (based on the amount of the aldehyde group-containing substance) is 1: 0.7-4, wherein the mass ratio of the water-soluble polymer to the urea compound is 1: 0.1 to 9, the pH value range of the solution B is 7.5 to 10.5, and the reaction time is 0.5 to 8 hours.

Further, the pH value range of the solution in the step (3) under the alkaline condition is 7.4-10.5, and the reaction time is 0.4-8 h.

Further, the coagulation bath for wet spinning in the step (4) is a saturated sodium sulfate aqueous solution, 0.01-0.9 wt% of boric acid is added, the temperature of the coagulation bath is 30-60 ℃, the drying temperature is 60-130 ℃, and the winding speed is 10-500 m/min.

Further, in the step (4), the heating curing rate is 1-20 ℃/min, the temperature is raised to 150-.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the spinning solution is prepared from the water-soluble polymer, the melamine, the aldehyde compound and the urea compound under the alkaline condition, so that the experimental steps are simplified, and the thermal property and the mechanical property are improved; the mixing of the solution A and the solution B is beneficial to the control of hydroxymethylation reaction and the structural design of the molecules of the obtained modified melamine resin, so that the modified melamine resin with a definite structure can be obtained, the control of the viscosity of the spinning solution is beneficial, good spinnability is obtained, and the flame retardance and the mechanical property can be optimized by controlling the proportion and the reaction time of the two solutions. The obtained modified melamine fiber is a three-dimensional cross-linked fiber, has no flame retardant additive, good flame retardant property, no toxicity due to slight smoke when the modified melamine fiber is extinguished after leaving flame and burned, and the mechanical property of the fiber is improved.

Detailed Description