CN1344821A - Fire-retardant fiber and its making process - Google Patents

Abstract

The invention relates to a flame-retardant fiber and a manufacturing method thereof. It is characterized in that the fiber formula is: the polymer and inorganic nanomaterials of the melamine-formaldehyde mixture account for 90-99% and 10-1% of the weight respectively; the molar ratio of the melamine-formaldehyde mixture is 1:1.2-1: 6. The formaldehyde and the added substance account for 85-30% and 15-70% of the mole of the formaldehyde mixture respectively; the added substance is at least one of ethylene glycol, ethylenediamine, glycine, etc. The manufacturing method is characterized in that the precondensed polymer is prepared according to the formula, and after being filtered, it is directly spun by centrifugal method; the obtained fiber is rapidly dried and shaped. Spinning process parameters are: pre-condensation polymer temperature: 35-100 ℃; pre-condensation polymer viscosity: 300-900 centipoise; pump feeding speed: 50-260 g/min; centrifugal disc line speed: 3000-7000 m/min ;Spinning temperature: 170-280°C. The invention can improve the mechanical performance of the flame-retardant fiber, thereby improving its wearing performance, and meanwhile has the characteristics of simple process, high efficiency and low cost.

Description

A kind of flame-retardant fiber and its manufacturing method

The invention relates to a chemical fiber material and a manufacturing method thereof, in particular to a flame-retardant fiber and a manufacturing method thereof. Its IPC main classification number is proposed to be Int.Cl ⁷ D06M 15/327.

At present, the flame retardant properties of most chemical fibers are generally obtained by adding flame retardants to the fiber solution by finishing, blending or copolymerization. This conventional manufacturing method has obvious disadvantages: one is that the addition of flame retardant will affect the spinning performance and mechanical properties of the fiber; the other is that the general flame retardant fiber will release a large amount of harmful gas when burning, Melt drops will affect the environment; the third is that the softening point of the chemical fiber is relatively low, so it is not resistant to high temperature. Therefore, people are constantly studying improvement methods. A more advanced improvement method is to use the condensation products of melamine and formaldehyde to prepare flame-retardant fibers. For example, the German patent DE2364091-B describes a method for preparing fibers from the condensation products of melamine and formaldehyde. The method is to spin the aqueous solution of the condensate into filaments at a certain temperature, while evaporating water and solidifying the pre-condensate. Since this method can form a cross-linked structure, it can better overcome the above-mentioned shortcomings. There are two kinds of spinning methods, "dry reaction spinning method" and "centrifugal spinning method", and the spinning speed is 10 to 500 m/min. However, the solidification process of the above method needs to last for a relatively long time, so a very long piping system is required after the spinneret. Furthermore, in order to be able to achieve high spinning speeds (up to 500 m/min), this method adds fiber-forming polymers (eg polyvinyl alcohol) to the MF condensate. However, the addition of such polymers affects the flame retardancy of the fibers and their textiles. In this regard, an improved method has been reported in the European patent EP93965-A: using N-alkyl substituted melamine etc. as polymerization monomers, adding 1--20% (weight) of alkali in the precondensate with formaldehyde A metal salt, preferably sodium bisulfite, is spun into filaments from this solution in a heated atmosphere. However, the added alkali metal salt is easy to decompose at high temperature, which is not conducive to the rapid formation of the fiber at high temperature during spinning, and also affects the mechanical properties of the fiber. In another European patent EP221330-A, another improvement method is described: melamine substituted with hydroxyalkyl group is used as a comonomer to modify its condensate with formaldehyde, which can also be spun into flame-retardant fiber. But in the European Patent EP221330-A, it is emphasized that the silk spun by centrifugal method needs to be heated in the hot air box for 90 minutes, and then continue to be kept for 30 to 60 minutes to improve the strength of the fiber, so that the spinning process or cycle is very long and the efficiency is not high. high. The spinning method adopted in the latter two patents (i.e. EP93965-A and patent EP221330-A) is the same as the spinning method provided by the aforementioned German patent (DE2364091-B), that is, the substitution reaction of melamine must be carried out earlier, This monomer is then reacted with formaldehyde. Although such an improved method can realize the spinning method provided by German patent (DE2364091-B) without adding polyvinyl alcohol, it all increases the production process, prolongs the production cycle, and improves the production cost.

The purpose of the present invention is to address the deficiencies of the prior art and provide a new flame-retardant fiber and its manufacturing method, which can improve the mechanical properties of the flame-retardant fiber, thereby improving the wearing performance of the flame-retardant fiber product, and at the same time has a production process It is simple, the production efficiency is improved, and the production cost is reduced.

The purpose of the present invention is achieved as follows: design a kind of flame-retardant fiber with melamine as main component, it is characterized in that this flame-retardant fiber formula is:

The polymer of melamine and formaldehyde mixture accounts for 90--99% of the weight of the flame-retardant fiber;

Inorganic nanomaterials account for 10--1% of the weight of flame-retardant fibers, of which,

The molar ratio of melamine to formaldehyde mixture is 1:1.2--1:6;

The formaldehyde mixture includes formaldehyde and additives, which respectively account for 85--30% and 15--70% of the mole of the formaldehyde mixture;

The added substance is at least one of the following substances: ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, ethylenediamine, p-phenylenediamine, triethanolamine, ethanolamine, Glycine, Glycolic Acid, Beta-Alanine, and Alpha-Alanine.

The present invention also designs a manufacturing method suitable for producing the above-mentioned flame-retardant fiber. It is characterized in that the precondensed polymer is made according to the formula, and after being filtered, it is directly spun by centrifugal spinning method; the obtained fiber is rapidly dried and formed. Described centrifugal spinning process parameter is:

Precondensation polymer temperature: 35--100°C;

Precondensed polymer viscosity: 300--900 centipoise;

Pump feeding speed: 50--260 g/min;

Centrifugal disk linear speed: 3000--7000 m/min;

Spinning temperature: 170--280°C.

The formulation and manufacturing method of the flame-retardant fiber of the present invention eliminates the need to carry out the substitution reaction process of melamine in the prior art, but adopts the direct reaction polymerization of melamine and formaldehyde and other mixtures, and adds a certain amount of melamine to the mixture. Inorganic nanomaterials are first made into pre-condensed polymers, which are then filtered and spun by a centrifugal method to make the flame-retardant fibers. The formula and production method of the flame-retardant fiber of the present invention can not only chemically modify the condensation polymer of melamine and formaldehyde, but also use inorganic nano-materials for physical mixing and modification, which is beneficial to improve the wearing performance and mechanical properties of the flame-retardant fiber. performance. The method of the present invention adopts the method of directly chemically modifying the pre-condensation polymer of melamine and formaldehyde, which greatly improves the spinnability of the pre-condensation polymer, and avoids the disadvantages of adding polyvinyl alcohol to spin and affecting the spinning speed. Reduced the production process of first modifying melamine, shortened the spinning process, and increased the spinning speed tenfold (from the existing spinning speed of 10--500 m/min to 3000-- 7000 m/min), increased production; and does not require a very long drying process, for example, in the EP221330-A patent, although centrifugal spinning is also used, in order to reach a certain strength, the spun silk needs to be heated by hot air The box is heated for 90 minutes, and then will continue to be kept for 30 to 60 minutes, that is, the spinning production time of the prior art should be more than 120 minutes, but the manufacturing method of the present invention does not need a very long drying process, and the spinning time only takes 30 minutes. Minutes, the spinning cycle is greatly shortened, which also means increased output. The production process is simplified, the energy consumption is reduced, the production cost is reduced, and the production efficiency is improved.

In order to improve the mechanical properties and temperature resistance of the flame-retardant fiber, the present invention also adds inorganic nanometer materials. The inorganic fillers used in the past generally have large particle sizes and poor bonding with the fiber matrix. When the fibers are subjected to external forces, they are prone to stress concentration, which leads to cracks and fiber breakage. The present invention uses inorganic nanoparticles as fillers, the significance of which is: on the one hand, since the diameter of the particles is greatly reduced, the surface area of the particles is also increased, so the contact area between the filler and the matrix is increased, and there are many active centers on the surface of the nanoparticles, and the surface area of the particles is also increased. It is conducive to the close combination of particles and fiber matrix, and has relatively good compatibility. It has dual functions of toughening and strengthening for flame-retardant fibers; on the other hand, because the diameter of nanoparticles is extremely small, it is easy to make the diameter of the spun flame-retardant The small size creates a necessary condition for increasing the fineness of the flame-retardant fiber. The average fineness or average diameter range of the flame-retardant fiber obtained by the method of the present invention can reach 2--8 μm, so the performance of the flame-retardant fiber can be improved.

The inorganic nanometer material used in the present invention is at least one of aluminum oxide, zinc oxide, calcium carbonate, titanium dioxide, silicon carbide, silicon nitride, magnesium oxide, and aluminum nitride. Inorganic nanomaterials account for 1--10% of the fiber weight. Water is used as a solvent in the reaction. When an aqueous formaldehyde solution is used, water may not be added. In the polycondensation reaction, the pH value of the system is generally controlled at 7-9.5, preferably 7.5-9. In the polycondensation liquid before spinning, a certain amount of curing agent should be added. Generally, the curing agent can be selected from sulfuric acid, formic acid, acetic acid, ammonium chloride, aniline sulfate, etc. The added amount is 0.05-2.5% of the weight of the precondensed polymer.

The manufacturing method of the flame-retardant fiber of the present invention is characterized in that the mixture of melamine and formaldehyde is directly reacted and polymerized according to the formula, and a certain amount of inorganic nanomaterials are added to the mixture. First make the pre-condensation polymer, after filtering, adopt the centrifugal method to directly spin to make the flame-retardant fiber; the process parameters of the centrifugal spinning are:

Precondensation polymer temperature: 35--100°C;

Precondensed polymer viscosity: 300--900 centipoise

Pump feeding speed: 40--260 g/min;

Centrifugal disk linear speed: 3000--7000 m/min;

Spinning temperature: 170--280°C.

The preferred parameters of the spinning process are:

Precondensation polymer temperature: 40--90°C;

Precondensed polymer viscosity: 400--800 centipoise

Pump feeding speed: 50--200 g/min;

Centrifugal disc linear speed: 4000--6000 m/min;

Spinning temperature: 190--270°C.

When the method of the present invention prepares the precondensed polymer, the formaldehyde solution and melamine can be mixed first, and then other formulation components can be added; however, all formulation components can also be added at the same time.

Specific examples of the present invention are given below.

Example 1:

Take 73 milliliters (1 mole of formaldehyde, 30 grams) of 37% formaldehyde solution, put 12.4 grams of ethanolamine (0.2 mole), 5 grams of nanometer aluminum oxide and 126 grams (1 mole) of melamine into the formaldehyde solution, stir After uniformity, adjust the pH value of the mixed solution to 7, and the reaction temperature is 35°C; when the viscosity reaches 300 centipoise, add 0.07 g of acetic acid, stop stirring, and immediately filter the mixed material; after filtering, enter the metering pump, Then enter the centrifugal spinning machine for spinning. The spinning process parameters are designed as follows: the pump supply rate is 100 g/min; the centrifugal disc line speed or spinning speed is 3000 m/min. Feed liquid can be spun into short fibers quickly. During the falling process, the wet short fiber fully meets the hot air in the spinning box with a temperature of 180°C, and quickly evaporates the moisture in the fiber. After the fiber falls into the receiver, it has been dried and formed, and then stayed for another 25 minutes. After further solid-state polycondensation, the finished flame-retardant fiber of the present invention is produced. It was determined that the average diameter of the obtained flame-retardant fiber was 8 μm.

Example 2:

Take 73 milliliters (1 mole of formaldehyde) of 37% formaldehyde solution, put 126 grams of melamine into it, stir evenly, then put 142.6 grams of ethylene glycol (2.3 moles) and 14 grams of nano-silicon carbide into the formaldehyde solution, pH The value is adjusted to 8, the reaction temperature is 60°C, when the viscosity reaches 800 centipoise, after adding 5.6 grams of formic acid, stop stirring, and immediately filter the mixed material; after filtering, enter the metering pump, and then enter the centrifugal spinning machine. The spinning process is the same as in Example 1, but the parameters are adjusted, and the pump supply is 90 g/min; the centrifugal disc line speed is 5000 m/min; the spinning temperature is 210°C, and the finished product of the present invention can be made Flame retardant fibers. It was determined that the average diameter of the obtained flame-retardant fiber was 3 μm.

Example 3:

Take 146 milliliters (2 moles of formaldehyde) of 37% formaldehyde solution, put 126 grams of melamine into it, stir well, then add 152 grams of propylene glycol (2 moles), 60 grams of ethylenediamine (1 mole), and 75 grams of glycine ( 1 mole) and 26 grams of nano-aluminum nitride and 20 grams of nano-silicon nitride are put into formaldehyde aqueous solution, the pH value is adjusted to 9, and the reaction temperature is gradually raised to 90 ° C. When the viscosity reaches 900 centipoise, add 7.8 grams of aniline sulfate After that, stop stirring, and immediately filter the mixed material; after filtering, enter the metering pump, and then enter the centrifugal spinning machine. The spinning process is the same as that of Example 1, and the parameters are adjusted as follows: the pump supply rate is 250 g/min; the centrifugal disk line speed is 7000 m/min; the spinning temperature is 270° C., and the finished flame-retardant fiber of the present invention can be produced. It was determined that the average diameter of the obtained flame-retardant fiber was 6 μm.

Example 4:

Get concentration and be 146 milliliters (2 moles of formaldehyde) of formaldehyde aqueous solution of 37%, put into 126 grams of melamine, after stirring evenly, add 90 grams of 1,4-butanediol (1 mole) and 108 grams of p-phenylenediamine (1 mol), 30 grams of nano-calcium carbonate, and 22 grams of nano-titanium dioxide are put into the aqueous formaldehyde solution, the pH value is adjusted to 8.5, and the reaction temperature is gradually raised to 70 ° C; when the viscosity reaches 700 centipoise, after adding 5 grams of sulfuric acid, stop stirring, And immediately filter the mixed material, after filtering, enter the metering pump, and then enter the centrifugal spinning machine. The spinning process is the same as in Example 1, but the parameters are adjusted, and the pump supply is 80 g/min; the centrifugal disc line speed is 6000 m/min; the spinning temperature is 240°C, and the finished product of the present invention can be made Flame retardant fibers. It was determined that the average diameter of the obtained flame-retardant fiber was 2 μm.

Claims (5)

1. one kind is the fire resistance fibre of main component with the melamine, it is characterized in that the prescription of this fire resistance fibre is:

The polymer of melamine and formaldehyde compound accounts for the 90-99% of fire resistance fibre weight;

Inorganic nano material accounts for fire resistance fibre weight 10-1%, wherein,

The mol ratio of melamine and formaldehyde compound is 1: 1.2-1: 6;

Described formaldehyde compound comprises formaldehyde and substance, and both account for the 85-30% and the 15-70% of formaldehyde compound mole respectively;

Described substance is at least a in the following material: ethylene glycol, propylene glycol, 1,4-butanediol, 1,3 butylene glycol, ethylenediamine, p-phenylenediamine (PPD), triethanolamine, monoethanolamine, glycine, glycollic acid, Beta-alanine and α alanine.

2. fire resistance fibre according to claim 1 is characterized in that described inorganic nano material is at least a in the following material: alundum (Al, zinc oxide, calcium carbonate, titanium dioxide, carborundum, silicon nitride, magnesia, aluminium nitride.

3. the manufacture method of fire resistance fibre according to claim 2 is characterized in that adopting the direct reactive polymerics of compound such as trimerization chloramines and formaldehyde by described prescription, also adds a certain amount of inorganic nano material in compound.Make prepolycondensate earlier, after filtering, adopt the centrifugal process spinning directly to make described fire resistance fibre; The technological parameter of described centrifugal process spinning is:

Prepolycondensate temperature: 35--100 ℃;

Prepolycondensate viscosity: 300--900 centipoise;

Pump feeding speed: 40--260 gram/minute;

The centrifugal pan linear velocity: 3000--7000 rice/minute;

Spinning temperature: 170--280 ℃.

4. the manufacture method of fire resistance fibre according to claim 3 is characterized in that the technological parameter of described centrifugal process spinning is:

Prepolycondensate temperature: 40-90 ℃;

Prepolycondensate viscosity: 400--800 centipoise

Pump feeding speed: 50--200 gram/minute;

The centrifugal pan linear velocity: 4000--6000 rice/minute;

Spinning temperature: 190--270 ℃.

5. according to the manufacture method of claim 3 or 4 described fire resistance fibres, it is characterized in that the average diameter scope according to the fire resistance fibre of this method manufacturing is 2--8 μ m.