WO2021114459A1

WO2021114459A1 - Halogen-free flame-retardant and smoke-suppressant fiber, and preparation method therefor

Info

Publication number: WO2021114459A1
Application number: PCT/CN2020/072277
Authority: WO
Inventors: 张晟; 邢程远; 李帮经
Original assignee: 江苏集萃先进高分子材料研究所有限公司
Priority date: 2019-12-13
Filing date: 2020-01-15
Publication date: 2021-06-17
Also published as: CN110938892A; CN110938892B

Abstract

Disclosed are a halogen-free flame-retardant and smoke-suppressant fiber, and a preparation method therefor. The halogen-free flame-retardant and smoke-suppressant fiber comprises the following components in parts by weight: 40-70 parts of a hydroxyl-rich or amino-rich polymer, 30-60 parts of cyclodextrin, and 3-7 parts of isocyanate. The hydroxyl-rich or amino-rich polymer and the cyclodextrin are blended, and undergo crosslinking after-treatment by means of the isocyanate, so as to obtain a blended fiber. The halogen-free flame-retardant and smoke-suppressant fiber has low manufacturing costs, good compatibility, a long service life, and excellent flame-retardant and smoke-suppressant performance.

Description

Halogen-free flame-retardant super-smoke-suppressing fiber and preparation method thereof

Technical field

The invention belongs to the technical field of fire-fighting materials, and relates to fiber functional materials, in particular to a halogen-free flame-retardant super-smoke-suppressing fiber and a preparation method thereof.

Background technique

Fire has always been an important threat to the safety of people's lives and property. According to the Fire and Rescue Bureau of the Ministry of Emergency Management, a total of 237,000 fires were reported in 2018, 1407 people were killed and 798 were injured, and a direct property loss of 3.675 billion yuan has been calculated. A large number of fiber materials in daily life are flammable materials, which pose great fire safety hazards. Taking indoor fires as an example, more than 94% of house fire deaths are related to the burning of upholstery furniture (Advanced materials, 2011, 23, 3926.). It is particularly worth noting that most of the casualties caused by the fire are caused by suffocation or poisoning caused by burning smoke (Journal of Materials Chemistry A, 2015, 3, 17064). Therefore, the design and preparation of flame-retardant and smoke-suppressing fiber materials has always been the focus of material scientists.

At present, the flame retardant properties of fiber materials are mainly given by chemical and physical methods. The chemical method generally involves the introduction of flame-retardant segments into the classic polymer segments through molecular design to achieve the flame-retardant effect. However, this kind of method often requires a multi-step chemical synthesis process, the process is complicated, and the cost is high. After many polymers are modified, their preventability decreases, and the prepared fibers cannot meet commercial requirements (Angewandte Chemie International Edition, 2010, 49,9644;). The physical method is to prepare flame retardant materials by directly blending in the fiber or coating the fiber surface with a flame retardant (Composites Part A: Appliedscience and Manufacturing, 2012, 43, 415; ACS nano, 2018, 12, 3103.). This method has simple preparation process and low cost, and is suitable for flame retardant modification of most commercial fibers. Despite the disadvantages of easy precipitation and migration of flame retardants, short service life, etc., it is still the main method of preparing commercial flame retardant fibers.

The early flame retardants for fibers were mainly halogen flame retardants. Halogen flame retardants have high flame retardant efficiency and good compatibility with the material matrix. However, the suffocating smoke produced by the burning of halogen flame retardants and the environmental pollution caused by the waste treatment of halogen-containing flame retardant materials have attracted more and more attention. At present, both the European Union and the United States have banned halogen-based flame retardants in a number of products. The new generation of halogen-free flame retardants are phosphorus-nitrogen flame retardants. Satisfactory progress has been made in its research, but flame-retardant materials based on phosphorus still have the problem of burning a large amount of smoke. This solves the threat of fire to property to a certain extent, but people's life safety is still not effectively guaranteed. Although some studies have reported that inorganic particles such as zinc oxide can be added to general plastic products to inhibit smoke generation, but because inorganic particles do not have spinnability, it will seriously hinder the material's fiber formation, so it cannot be obtained by this method. Fiber material with reliable mechanical strength.

The ideal flame-retardant fiber should have the following characteristics: 1) It can be self-extinguished after being ignited; 2) Only a small amount of smoke is generated after burning, and the smoke composition is non-toxic; 3) The spinnability is good, and it has the same characteristics as ordinary commercial fibers. 4) The cost of raw materials is low, the process is simple, and it is easy to scale. At the same time, it also has good durability and long service life.

Summary of the invention

The purpose of the present invention is to provide a halogen-free flame-retardant super-smoke suppression fiber and a preparation method thereof. The halogen-free flame-retardant super-smoke suppression fiber has low manufacturing cost, excellent compatibility, long service life, and exhibits excellent flame retardancy and Smoke suppression effect.

In order to achieve the above technical effects, the present invention is specifically implemented through the following technical solutions:

A halogen-free flame-retardant super-smoke-suppressing fiber, which is a blended fiber obtained by blending a polymer rich in hydroxyl or amino groups with cyclodextrin, and cross-linked by isocyanate post-treatment. The halogen-free flame-retardant super-smoke-suppressing fiber comprises the following components in parts by weight: 40-70 parts of hydroxyl- or amino-rich polymer, 30-60 parts of cyclodextrin, and 3-7 parts of isocyanate. And the three components are cross-linked by covalent bonds to form a three-dimensional network structure.

Preferably, the halogen-free flame-retardant super-smoke suppression fiber comprises the following components in parts by weight: 40-60 parts of hydroxyl- or amino-rich polymer, 40-60 parts of cyclodextrin, and 5-7 parts of isocyanate.

The polymers rich in hydroxyl or amino groups are natural or synthetic polymer materials that are soluble in water, including but not limited to polyvinyl alcohol, cellulose, or chitosan.

The cyclodextrin is β-cyclodextrin or a derivative thereof, preferably β-cyclodextrin.

The isocyanate is an isocyanate molecule containing two or more -NCO groups, including but not limited to toluene diisocyanate, diphenylmethane diisocyanate or hexamethylene diisocyanate.

In another aspect of the present invention, a method for preparing the above-mentioned halogen-free flame-retardant super-smoke suppression fiber is provided, which includes the following steps:

1) Soak the polymer in water overnight, add cyclodextrin, stir to dissolve at 50-95°C, and leave to defoam to obtain a spinning solution;

2) Extruding the spinning solution into a coagulation bath through a spinning machine to coagulate the nascent fiber;

3) The nascent fiber is stretched and heat-set, immersed in an ethyl acetate solution of isocyanate, and reacted at 50～90℃ for 6～24h;

4) After alcohol washing, water washing and drying, a halogen-free flame-retardant super-smoke-suppressing fiber is obtained.

Further, the mass concentration of the polymer in the spinning solution prepared in step (1) is 13%-40%, and the mass concentration of the cyclodextrin is 10%-40%.

Further, the coagulation bath described in step (2) is a saturated ammonium sulfate solution, and the temperature is 30-60°C, preferably 50-60°C.

Further, in step (3), the stretching ratio is 1:1 to 1:5, and the stretching temperature is 60 to 90°C.

Further, in step (3), the heat setting time is 40-80 s, and the temperature is 180-220°C.

Further, the volume fraction of the isocyanate solution in step (3) is 5.0% to 10.0%.

The beneficial effects of the present invention are:

The flame-retardant and smoke-suppressing fiber of the present invention adopts cyclodextrin with excellent spinnability and natural non-toxic source as an organic green flame retardant for blending with common commercial polyhydroxy or amino polymers. And after forming the fiber, it forms a cross-linked structure with isocyanate through simple cross-linking and finishing. β-cyclodextrin is of natural origin (prepared by enzymatic hydrolysis of starch), low in price, and has excellent char-forming effect; and, unlike most other flame retardants, it has excellent spinnability and is different from other hydroxyl groups. Or when blended with amino fiber raw materials, it has excellent compatibility, does not cause phase separation, and greatly reduces mechanical properties. When the hydroxy or amino/cyclodextrin blended fiber is cross-linked with isocyanate, it not only gives the fiber good durability and long service life, but more importantly: the dense cross-linked structure, and the synergy of cyclodextrin and isocyanate Flame-retardant effect, so that the entire fiber material can form a ceramic-like dense carbon layer when burning, showing excellent flame-retardant and smoke suppression effects.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The invention provides a halogen-free flame-retardant super-smoke-suppressing fiber and a preparation method thereof, which specifically includes the following steps:

1) Preparation of spinning solution: take polymer materials with different mass fractions and soak them in water overnight to weaken the possible hydrogen bond interactions, add cyclodextrins with different mass fractions, and mechanically under heating conditions (50～95℃) Stir and dissolve, and let it stand for 10 minutes to defoam to obtain a spinning solution. In the spinning solution, the mass concentration of the polymer is 13%-40%, and the mass concentration of the cyclodextrin is 10%-40%.

The polymer is a natural or synthetic polymer material that is rich in hydroxyl or amino groups and can be dissolved in an aqueous solution, including but not limited to polyvinyl alcohol, cellulose, chitosan, and the like.

The cyclodextrin is β-cyclodextrin and its derivatives, preferably β-cyclodextrin.

By weight: 40 to 70 parts of polymer rich in hydroxyl or amino groups, 30 to 60 parts of cyclodextrin. Preferably, 40-60 parts of hydroxyl- or amino-rich polymer and 40-60 parts of cyclodextrin.

2) Preparation of nascent fiber: the prepared spinning solution is extruded through the spinneret of the wet spinning machine, coagulated in the coagulation bath (saturated ammonium sulfate solution) and the first 2 times stretching is finally collected by the winding device. The temperature of the coagulation bath is 30 to 60°C, preferably 50 to 60°C.

3) Thermal drawing: the obtained nascent fiber is gradually drawn through two stages, the total draw ratio of the two stages is 1:1 to 1:5, and the drawing temperature is 60 to 90°C.

4) Heat setting: The heat-stretched fiber is sent to the heat setting chamber, the heat setting time is 40-80s, and the heat setting temperature is 180-220°C.

5) Cross-linking: add 5.0% to 10.0% of isocyanate-based cross-linking agent (v/v) in ethyl acetate to dissolve into a solution, immerse the fiber in the stretched state, and react at 50 to 90°C for 6 to 24 hours .

Among them, the isocyanate crosslinking agent is an isocyanate molecule containing two or more -NCO groups, including but not limited to toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

Parts by weight: 3-7 parts of isocyanate crosslinking agent, preferably 5-7 parts.

6) Alcohol washing: industrial ethanol washing is used to remove unreacted isocyanate-based crosslinking agent and its by-products.

7) Washing with water: Washing with water to remove residual coagulation bath salts and other impurities.

8) Drying: Use a blast drying box to remove the solvent (the drying temperature range is 50-80°C) to obtain halogen-free flame-retardant super-smoke-suppressing fiber.

Example 1

1) Preparation of spinning solution: Add 15% of polyvinyl alcohol 1799 raw material to water, soak in water overnight to weaken the hydrogen bond interaction, and add 15% of β-cyclodextrin to water. Dissolve under mechanical stirring at 80°C, and leave to defoam for 10 minutes to prepare spinning solution;

2) Preparation of nascent fiber: the prepared spinning solution is extruded through the spinneret of the wet spinning machine, enters the coagulation bath of saturated ammonium sulfate solution for coagulation and the first two-fold stretching is finally collected by the winding device Nascent fiber

3) Thermal drawing: the obtained nascent fiber is stretched in two stages, and the total stretching ratio of the two stages is 1:5;

4) Heat setting: The fiber that has been heat drawn is sent to the heat setting room, the heat setting temperature is 220℃, and the heat setting time is 60s;

5) Cross-linking: add 7.5% hexamethylene diisocyanate (v/v) to ethyl acetate to dissolve it to make a solution, immerse the fiber in it in a stretched state, and react at 77°C for 12h;

6) Alcohol washing: industrial ethanol washing is used to remove unreacted isocyanate-based crosslinking agent and its by-products;

7) Washing with water: Washing with water to remove residual coagulation bath salts and other impurities;

8) Drying: Use a blast drying oven at 60°C to remove the solvent to obtain a halogen-free flame-retardant super-smoke-suppressing fiber.

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method described in this example has a linear density of 6.9dTex, a breaking strength of 2.1cN/dTex, a breaking elongation of 35.8%, and a limiting oxygen index of 39.5%, UL94 Reaching the V0 level, the smoke emission is reduced by 85.7%.

Example 2

1) Preparation of spinning solution: Add 13% of polyvinyl alcohol 1788 raw material to water, soak in water overnight to weaken the hydrogen bond interaction, and add 9.5% of the relative water mass fraction of β-hydroxypropyl ring Dextrin, mechanically stirred and dissolved at 90°C, and allowed to stand for 10 minutes to defoam to obtain a spinning solution;

3) Thermal drawing: the obtained nascent fiber is stretched in two stages, and the total stretching ratio of the two stages is 1:1;

4) Heat setting: the heat-stretched fiber is sent to the heat setting room, the heat setting temperature is 180℃, and the heat setting time is 60s;

5) Cross-linking: add 5.0% toluene diisocyanate (v/v) in ethyl acetate to dissolve to make a solution, immerse the fiber in the stretched state, and react at 70°C for 6 hours;

8) Drying: Use a blast drying oven at 50°C to remove the solvent to obtain halogen-free flame-retardant super-smoke-suppressing fiber.

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method of the present invention has a linear density of 7.1dTex, a breaking strength of 1.8cN/dTex, a breaking elongation of 58.8%, a limiting oxygen index of 32.2%, and UL94 reaching At V0 level, the smoke emission is reduced by 79.9%.

Example 3

1) Preparation of spinning solution: Add 19% of the polyvinyl alcohol 2099 raw material in water, soak in water overnight to weaken the hydrogen bond interaction, and add 15% of β-cyclodextrin relative to the mass of water. Dissolve under mechanical stirring at 90°C, and let it stand for 10 minutes to defoam to obtain spinning solution;

3Heat drawing: the obtained nascent fiber is stretched in two stages, and the total stretch ratio of the two stretches is 1:2;

4) Heat setting: the heat-stretched fiber is sent to the heat setting room, the heat setting temperature is 200℃, and the heat setting time is 60s;

5) Cross-linking: Add 7.5% phenylmethane diisocyanate (v/v) to ethyl acetate to dissolve it to make a solution, immerse the fiber in the stretched state, and react at 80°C for 12h;

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method of the present invention has a linear density of 7.5dTex, a breaking strength of 1.7cN/dTex, a breaking elongation of 54.8%, and a limiting oxygen index of 35.5%, UL～ 94 reaches the V0 level, and the smoke emission is reduced by 88.5%.

Example 4

1) Preparation of spinning solution: add 13% sodium cellulose sulfonate relative to its mass fraction in water, soak in 5% NaOH water overnight, add 14% relative water mass fraction of β-cyclodextrin, in Dissolve under mechanical stirring at 80°C, and leave to defoam for 10 minutes to prepare spinning solution;

3) Hot drawing: the obtained nascent fiber is stretched in two stages, and the total stretching ratio of the two stages is 1:2;

5) Cross-linking: add 10.0% toluene diisocyanate (v/v) in ethyl acetate to dissolve it to make a solution, immerse the fiber in it in a stretched state, and react at 67°C for 24h;

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method of the present invention has a linear density of 7.8dTex, a breaking strength of 1.27cN/dTex, a breaking elongation of 38.4%, a limiting oxygen index of 42.0%, and UL～ 94 reaches the V0 level, and the smoke emission is reduced by 91.6%.

Example 5

1) Preparation of spinning solution: add 15% sodium cellulose sulfonate raw material relative to its mass fraction in water, soak in 5% NaOH water overnight to weaken the hydrogen bond interaction, add 13% relative water mass fraction β ~Cyclodextrin, mechanically stirred and dissolved at 95°C, and allowed to stand for 10 minutes to defoam to obtain a spinning solution;

3) Thermal drawing: the nascent fiber obtained is drawn through two stages, the total drawing ratio is 1:3;

5) Cross-linking: add 5.0% hexamethylene diisocyanate (v/v) to ethyl acetate to dissolve it to make a solution, immerse the fiber in the stretched state, and react at 77°C for 24h;

8) Drying: Use a blast drying oven at 80°C to remove the solvent to obtain halogen-free flame-retardant super-smoke-suppressing fiber.

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method of the present invention has a linear density of 8.20 dTex, a breaking strength of 1.05 cN/dTex, a breaking elongation of 34.2%, and a limiting oxygen index of 40.8%, UL ~ 94 reaches the V0 level, and the smoke emission is reduced by 88.7%.

Example 6

1) Preparation of spinning solution: add 13% chitosan relative to its mass fraction in water, soak in 2% acetic acid water overnight to weaken the hydrogen bond interaction, add 15% relative water mass fraction β～ Cyclodextrin, mechanically stirred and dissolved at 95°C, and allowed to stand for 10 minutes to defoam to obtain a spinning solution;

3) Thermal drawing: the nascent fiber obtained is drawn through two stages, the total drawing ratio is 1:1;

5) Cross-linking: add 10.0% diphenylmethane diisocyanate (v/v) in ethyl acetate to dissolve it to make a solution, immerse the fiber in the stretched state, and react at 77°C for 24h;

The halogen-free flame-retardant super-smoke-suppressing fiber prepared by the method of the present invention has a linear density of 8.1 dTex, a breaking strength of 0.9 cN/dTex, a breaking elongation of 30.3%, and a limiting oxygen index of 46.2%, UL ~ 94 reaches the V0 level, and the smoke emission is reduced by 93.5%.

Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and substitutions can be made to these examples without departing from the principle and spirit of the present invention. Variations, the scope of the present invention is defined by the appended claims and their equivalents.

Claims

A halogen-free flame-retardant super-smoke-suppressing fiber, characterized in that, the halogen-free flame-retarding super-smoke-suppressing fiber comprises the following components in parts by weight: 40-70 parts of a polymer rich in hydroxyl or amino groups, cyclodextrin 30-60 parts, 3-7 parts isocyanate.
The halogen-free flame-retardant super-smoke-suppressing fiber according to claim 1, wherein the halogen-free flame-retarding super-smoke-suppressing fiber comprises the following components by weight: a polymer rich in hydroxyl or amino group 40 ~60 parts, 40~60 parts of cyclodextrin, 5~7 parts of isocyanate.
The halogen-free flame-retardant super-smoke-suppressing fiber according to claim 1 or 2, wherein the polymer rich in hydroxyl or amino groups is a natural or synthetic polymer that is soluble in water.
The halogen-free flame-retardant super-smoke-suppressing fiber according to claim 1 or 2, wherein the cyclodextrin is β-cyclodextrin or a derivative thereof.
The halogen-free flame-retardant super-smoke-suppressing fiber according to claim 1 or 2, wherein the isocyanate is an isocyanate molecule containing two or more -NCO groups.
The preparation method of halogen-free flame-retardant super-smoke-suppressing fiber according to claim 1, characterized in that it comprises the following steps:

1) Soak the polymer in water overnight, add cyclodextrin, stir to dissolve at 50-95°C, and leave to defoam to obtain a spinning solution;

2) Extruding the spinning solution into a coagulation bath through a spinning machine to coagulate the nascent fiber;

3) The nascent fiber is stretched and heat-set, immersed in an ethyl acetate solution of isocyanate, and reacted at 50～90℃ for 6～24h;

4) After alcohol washing, water washing and drying, a halogen-free flame-retardant super-smoke-suppressing fiber is obtained.
The preparation method according to claim 6, characterized in that the mass concentration of polymer in the spinning solution prepared in step (1) is 13%-40%, and the mass concentration of cyclodextrin is 10%-40% .
The preparation method according to claim 6, wherein the coagulation bath in step (2) is a saturated ammonium sulfate solution, and the temperature is 30-60°C.
The preparation method according to claim 6, wherein the stretching ratio in step (3) is 1:1 to 1:5, and the stretching temperature is 60 to 90°C.
The preparation method according to claim 6, wherein the volume fraction of the isocyanate solution in step (3) is 5.0% to 10.0%.