阅读说明：本技术 通过共聚制备酚醛/蜜胺纤维的方法 (Method for producing phenolic/melamine fibres by copolymerization ) 是由 杨凯 焦明立 李洁 刁泉 张啸梅 曹健 于 2019-11-27 设计创作，主要内容包括：本发明公开了一种通过共聚制备酚醛/蜜胺纤维的方法,在两份相同的高分子水溶液中分别加入三聚氰胺和醛类(甲溶液),酚类和醛类(乙溶液),碱性条件反应；甲、乙溶液共混后继续反应至结束,进行纺丝、热固化,自然降温,得到酚醛/蜜胺纤维。本发明制备的酚醛/蜜胺纤维作为三维交联型纤维,兼具酚醛纤维、蜜胺纤维的阻燃、隔热、燃烧低烟少毒、成本低、力学性能好、耐高温等优点,具有广阔的应用前景。(The invention discloses a method for preparing phenolic aldehyde/melamine fiber by copolymerization, which comprises the steps of respectively adding melamine and aldehydes (methyl solution) and phenols and aldehydes (ethyl solution) into two parts of same high-molecular aqueous solution, and reacting under alkaline conditions; and blending the solution A and the solution B, continuing to react until the reaction is finished, spinning, thermocuring, and naturally cooling to obtain the phenolic/melamine fiber. The phenolic/melamine fiber prepared by the invention is used as a three-dimensional crosslinking fiber, has the advantages of flame retardance, heat insulation, low smoke and low toxicity in combustion, low cost, good mechanical property, high temperature resistance and the like of the phenolic fiber and the melamine fiber, and has wide application prospect.)

1. A process for the preparation of phenolic/melamine fibres by copolymerisation characterised in that it comprises the steps of:

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

(2) adding a phenolic compound, an aldehyde compound and an alkaline catalyst into the solution B, and reacting for a period of time at 45-96 ℃ to obtain a solution B;

(3) mixing the solution A and the solution B, adjusting the pH value to alkaline conditions by using an alkaline catalyst, and continuously reacting for a period of time at the temperature of 40-98 ℃ to obtain a phenolic aldehyde/melamine copolymer resin spinning solution;

(4) and (3) carrying out wet spinning on the obtained phenolic/melamine copolymer resin spinning solution to obtain nascent fiber, drying, winding, and finally heating and curing in an oven at a certain heating rate to obtain the phenolic/melamine fiber.

2. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the water-soluble polymer in the step (1) is one of PVP, water-soluble modified starch, PVA, PEG, polyvinyl formal or water-soluble modified cellulose.

3. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the alkaline catalyst is one of sodium hydroxide, potassium hydroxide, triethanolamine, sodium bicarbonate, magnesium hydroxide or calcium hydroxide; the aldehyde compound is one of formaldehyde, glutaraldehyde, acetaldehyde and paraformaldehyde; the phenolic compound is one of phenol, cardanol, chlorophenol, cresol and nitrophenol.

4. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the mass content of the high polymer in the water-soluble high polymer solution in the step (1) is 3-20%.

5. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the molar ratio of the melamine to the aldehyde compounds (based on the amount of aldehyde groups contained in the substances) in the solution A in the step (1) is 1 (0.7-5), the mass ratio of the water-soluble polymer to the melamine is 1:0.5-8, the pH value range of the solution A under the alkaline condition is 7.4-11, and the reaction time is 0.4-10 h.

6. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the molar ratio of the phenolic compound to the aldehyde compound (based on the amount of aldehyde group contained in the substance) in the solution B in the step (2) is 1 (0.7-2), the mass ratio of the water-soluble polymer to the phenolic compound is 1 (0.1-6), the pH value range of the solution B is 7.5-11.5, and the reaction time is 0.5-5 h.

7. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: the pH value range of the solution in the step (3) under the alkaline condition is 7.8-12, and the reaction time is 0.4-8 h.

8. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: and (4) adding 0.1-5 wt% of boric acid into the coagulation bath of the wet spinning at 10-60 ℃ in the step (4), wherein the drying temperature is 60-130 ℃ and the winding speed is 10-500 m/min.

9. Process for the preparation of phenolic/melamine fibres by copolymerization according to claim 1, characterised in that: in the step (4), the heating rate is 1-30 ℃/min, the temperature is raised to 150 ℃ and 230 ℃, the temperature is kept for 0.1-2h, and the phenolic aldehyde/melamine fiber is obtained after natural cooling and then taken out.

Technical Field

The invention belongs to the field of preparation of special fibers, and particularly relates to a preparation method of a phenolic/melamine fiber with excellent performance, which is obtained by copolymerization of a phenolic compound and melamine to prepare a spinning solution, wet spinning and thermosetting.

Background

With the increasing demand for fire safety, flame retardant textiles are experiencing a rapid increase in demand. The phenolic resin material has the advantages of heat resistance, difficult combustion, self-extinguishment, low smoke, flame penetration resistance, no dropping in fire and the like [ invarior, Yinghua, and Dairyujia ] development of novel toughened flame-retardant phenolic resin foam [ J ] application chemical industry, 2010(2): 247-.

Melamine fiber is a new type of flame retardant fiber and is prepared through condensation polymerization of melamine and formaldehyde. Melamine fiber has good flame retardancy, high limiting oxygen index, continuous high temperature resistance, no melt and drip in the combustion process, and no deterioration of fire resistance in the whole use process [ Berbener H, Liu Yongjian.Basofil: a novel melamine-based heat-resistant flame-retardant fiber [ J ]. foreign textile technology (chemical fiber, dyeing and finishing, environmental protection booklet), 1996(4):25-28 ], and has been widely applied to some high temperature resistant fields because of low melamine price. But the melamine has the disadvantages of high functionality, high crosslinking degree and the like, has poor toughness, is not easy to synthesize or has short resin storage time after synthesis; the centrifugal spinning is used for production, the production efficiency is low, and the fiber thickness is not uniform. Thus hindering the preparation of melamine fibers and increasing the high performance of melamine fibers has become a major issue.

The melamine fiber and the phenolic fiber belong to intrinsic flame retardant fiber but have different defects, and the patent combines the advantages of the melamine fiber and the phenolic fiber to prepare the phenolic/melamine fiber with more balanced performance.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for preparing phenolic aldehyde/melamine fiber by copolymerization, which comprises the steps of respectively adding melamine, phenolic compounds and aldehyde into a high-molecular aqueous solution, carrying out copolymerization reaction to obtain a spinning solution, and carrying out wet spinning and thermocuring to prepare the three-dimensional crosslinked flame-retardant fiber.

In order to solve the technical problems, the invention adopts the following technical scheme:

a process for the preparation of phenolic/melamine fibres by copolymerisation, which comprises the steps of:

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

(2) adding a phenolic compound, an aldehyde compound and an alkaline catalyst into the solution B, and reacting for a period of time at 45-96 ℃ to obtain a solution B;

(3) mixing the solution A and the solution B, adjusting the pH value to alkaline conditions by using an alkaline catalyst, and continuously reacting for a period of time at the temperature of 40-98 ℃ to obtain a phenolic aldehyde/melamine copolymer resin spinning solution;

(4) and (3) carrying out wet spinning on the obtained phenolic/melamine copolymer resin spinning solution to obtain nascent fiber, drying, winding, and finally heating and curing in an oven at a certain heating rate to obtain the phenolic/melamine fiber.

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

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

Further, the mass content of the high polymer in the water-soluble high polymer solution in the step (1) is 3-20%.

Further, the molar ratio of the melamine to the aldehyde compounds (based on the amount of aldehyde groups contained) in the solution obtained in the step (1) is 1: 0.7-5, wherein the mass ratio of the water-soluble polymer to the melamine is 1:0.5-8, the pH value range of the solution A under the alkaline condition is 7.4-11, and the reaction time is 0.4-10 h.

Further, in the step (2), the molar ratio of the phenolic compound to the aldehyde compound (based on the amount of aldehyde group contained in the material) in the ethanol solution is 1: 0.7-2, wherein the mass ratio of the water-soluble polymer to the phenolic compound is 1:0.1 to 6, the pH value range of the solution B is 7.5 to 11.5, and the reaction time is 0.5 to 5 hours.

Further, the pH value of the solution in the step (3) under the alkaline condition ranges from 7.8 to 12, and the reaction time is 0.4 to 8 hours.

Further, the coagulating bath for wet spinning in the step (4) is a saturated sodium sulfate aqueous solution, the temperature is 10-60 ℃, 0.1-5% by weight of boric acid is added, the drying temperature is 60-130 ℃, and the winding speed is 10-500 m/min.

Further, in the step (4), the heating rate is 1-30 ℃/min, the temperature is raised to 150-.

The invention has the following beneficial effects: the raw materials of the phenolic compound, the melamine and the aldehyde compound are cheap and easy to obtain, strong acid, strong alkali or strong corrosive conditions are not needed, the reaction is carried out at normal pressure, and the reaction temperature is low; the combination of the phenols and the melamine balances the functionality of the phenols and the melamine, realizes excellent spinnability of the solution and controllable proceeding of crosslinking reaction, and is beneficial to controlling the mechanical property of the fiber; the single alkali environment reaction process is beneficial to simplifying the reaction process, improving the production efficiency, reducing the equipment cost, directly spinning without further treatment, mild spinning conditions and high spinning speed, the obtained nascent fiber only needs to be thermally cured to obtain the phenolic/melamine fiber, and the thermal curing and crosslinking are simple and easy; the obtained phenolic aldehyde/melamine fiber has a three-dimensional cross-linked structure, does not need to be added with a flame retardant, and has excellent flame retardant performance, high limited oxygen index, less release of toxic and harmful gases during combustion, excellent heat resistance and better mechanical properties.

Detailed Description

The present invention will be further described with reference to the following examples, which are intended to be illustrative only and not to be limiting of the invention in any way, and any person skilled in the art can modify the present invention by applying the teachings disclosed above and applying them to equivalent embodiments with equivalent modifications. Any simple modification or equivalent changes made to the following embodiments according to the technical essence of the present invention, without departing from the technical spirit of the present invention, fall within the scope of the present invention.