CN113355762B

CN113355762B - High-strength acetate fiber and preparation method thereof

Info

Publication number: CN113355762B
Application number: CN202110583218.4A
Authority: CN
Inventors: 林资原
Original assignee: Shanghai Maoteng Knitting Co ltd
Current assignee: Shanghai Maoteng Knitting Co ltd
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2022-10-28
Anticipated expiration: 2041-05-27
Also published as: CN113355762A

Abstract

The invention discloses a preparation method of high-strength acetate fiber, which comprises the following steps: dissolving acetate fiber into an organic solvent to obtain an acetate solution; adding a modifier and polyethylene glycol into the acetic ester solution to obtain a wet spinning solution; and spinning the wet spinning solution through a spinneret plate to obtain the high-strength acetate fiber. The preparation method has simple process, low cost, easy operation and easy industrialization; the modified cellulose acetate fiber has high strength, good damage resistance, greatly improved wear resistance and thermal stability, and no toxicity, environmental protection and good application prospect because the natural component dopamine is used as an additive.

Description

High-strength acetate fiber and preparation method thereof

Technical Field

The invention relates to the field of chemistry, in particular to a high-strength acetate fiber and a preparation method thereof.

Background

Acetate is next to viscose in regenerated fibre. Cellulose was first prepared as early as 1864 by acetylation with acetic anhydride to give triacetylated fibers. In the beginning of the 20 th century, partial hydrolysis of triacetate was attempted and the cellulose acetate was successfully converted into diacetate Cellulose (CDA). In comparison, CDA is easily dissolved in common nontoxic solvents such as acetone and other organic solvents, and is convenient for further processing into acetate fiber filaments, thereby starting industrialization of acetate fibers. The acetate fiber has the advantages of real silk, and has the advantages of elegant luster, soft hand feeling, light weight and good elasticity. As a textile, acetate fibers also have the advantages of good moisture absorption, quick drying, good drapability, no pilling, small shrinkage, stable size and the like, and have attracted much attention due to the excellent properties of no staining of fabrics and easy washing, and since the last 80 s, american acetate fibers have gradually replaced viscose filaments. In addition, acetate fibers are also widely applied to the fields of cigarette filters, film bases, plastic products and the like.

As textile fibers, acetate fibers have the greatest defects of low fiber strength and poor durability. The dry strength of the common acetate fiber is only 1.1-1.2eN/dtex, the fiber strength is low, the difficulty of later fiber processing and spinning is increased, and the application and popularization are limited. In addition, the durability of acetate fibers is also poor. Research to improve acetate fiber strength and increase durability is therefore an important concern in the art.

To address these problems, eastman corporation introduced hollow acetate fibers 50 that had smooth hand and improved fiber strength to some extent. By adding functions such as antibacterial acetate fiber Microafe and blend fiber Celanna and blending polyester fiber and acetate fiber to prepare yarn, the durability of the fiber is improved and the fiber is easy to dye. The layered and functionalized acetate fibers play a very important role in promoting the application of the acetate fibers. Other modification treatments of the acetate fiber, such as forming micropores on the surface of the acetate fiber to obtain rich drapability; it can also be used to improve the hand feeling and dyeability of the fiber by alkali treatment, enzyme treatment and heat treatment. However, the current research progress is very limited to the problem of low strength of acetate fiber, and the modification is mainly carried out by fiber composite processing/spinning so far. If polyester and acetate fiber are compositely modified, elbea modified fiber of imperial corporation increases the strength of the fiber to a certain extent, and keeps the special quick-drying and light feeling of the acetate fiber, but the product is easy to peel and prickle due to the natural incompatibility of the acetate fiber and the polyester. The patent CN 102614785A improves the strength of the fiber to a certain extent by blending modified polyvinyl chloride/cellulose acetate, but the fiber is too strong in hydrophobicity and is easy to be polluted by organic matters such as grease and protein, and the product is not environment-friendly. The patent CN105002592A discloses an acetonitrile fiber and a preparation method thereof, the chemical stability and the thermal stability are greatly improved by the modification treatment of the blended cellulose acetate and acrylic fiber, but the yield is low and the strength is not obviously improved. Other modification methods such as patent CN105732824a using acetyl silk fibroin to blend modified cellulose acetate and US patent US2000/6143884/Acelon disclosing a manufacturing method for reducing viscosity of cellulose viscose by using a cosolvent method all belong to the technical field of cellulose acetate preparation, but are not environment-friendly or have high cost and can not be commercialized, and have certain limitations.

Disclosure of Invention

In view of the defects, the invention provides the high-strength acetate fiber and the preparation method thereof, and the preparation method has the advantages of simple process, low cost, easy operation and easy industrialization; the modified acetate fiber has high strength, better damage resistance and greatly improved wear resistance and thermal stability.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of high-strength acetate fibers comprises the following steps:

dissolving acetate fiber into an organic solvent to obtain an acetate solution;

adding a modifier and polyethylene glycol into the acetic ester solution to obtain a wet spinning solution;

and spinning the wet spinning solution through a spinneret plate to obtain the high-strength acetate fiber.

In accordance with one aspect of the present invention, the acetate fibers include one or more of monoacetate fibers, diacetate fibers and triacetate fibers.

In accordance with one aspect of the present invention, dissolving the acetate fibers in an organic solvent to obtain an acetate solution comprises: dissolving acetate fiber into an organic solvent, adding an organic weak base, and adjusting the pH of the solution to 8-12 to obtain an acetate solution.

In accordance with one aspect of the invention, the organic solvent comprises one of acetone, NMMO, DMAP.

According to one aspect of the invention, the weak organic base comprises triethylamine and ammonia.

According to one aspect of the present invention, the wet spinning solution obtained by adding a modifier and polyethylene glycol to the acetate solution comprises: stirring and heating the acetate solution, adding a modifier and polyethylene glycol in the process, continuously stirring until a drawing and hanging state occurs, and cooling to obtain a wet spinning solution.

According to one aspect of the invention, the modifier is one of poly-bis-schiff base, dopamine or a combination of two.

According to one aspect of the invention, the poly-bis-schiff base has a molecular formula of [ R1N = C = NR2] N, wherein R1 and R2 are one or a combination of any two or more of a saturated and unsaturated aliphatic chain, an aromatic ring and a heterocyclic ring.

According to one aspect of the invention, the poly bis-schiff base reaction temperature is 100 ℃ and the dopamine reaction temperature is 50 ℃.

In accordance with one aspect of the invention, the spinneret plate is one of 28 holes/0.040 mm and 28 holes/0.060 mm.

The invention has the beneficial effects that: the invention respectively blends and copolymerizes and modifies the acetate fibers by using dopamine and a high-reactivity crosslinking polymer [ R1N = C = NR2] N (polycarbodiimide or poly-bis-Schiff base). The acetate fiber is wrapped by strong dopamine adsorption, and is treated and modified on the surface of the acetate fiber, and the poly bis-Schiff base cross-linked polymer has high activity and is easy to generate nucleophilic addition of affinity functional groups such as carboxyl, amino, hydroxyl and water, and is widely applied to polylactic acid and polyurethane cross-linking tackifying reaction. In the patent, the purpose of modification is achieved by utilizing the fact that free hydroxyl groups exist in the molecular structure of the cellulose acetate fiber and the cellulose acetate fiber rapidly undergo a crosslinking reaction. Through the poly bis-Schiff base modified acetate fiber, the tensile strength and the durability (wear resistance) of the acetate fiber can be effectively improved, and the thermal stability of the acetate fiber is greatly improved. The modified acetate fiber can be dissolved into spinning solution by a conventional solvent method and then can be subjected to wet spinning. In the patent, the addition amounts of dopamine and poly-bis-Schiff base are small, and the production cost of acetate fibers is not increased basically. The dopamine can effectively coat the outer layer, and the poly-bis-Schiff base is subjected to cross-linking polymerization, so that the poly-bis-Schiff base not only is on the surface of the acetate fiber, but also changes the internal structure of the acetate fiber, and finally has great influence on the physical and mechanical properties of the fiber. The two-step modification method of the chemical acetate fiber and the physical acetate fiber can not reduce the solubility of the modified acetate fiber in a common solvent, thereby obtaining the acetate fiber with high strength performance without changing the wet spinning process. The high-strength acetate fiber with the dry strength of 1.8-2.9 eN/dtex and the fracture growth rate of 25-35 percent at 25 ℃ can be obtained, and the softening temperature of the acetate fiber is 200-230 ℃ which is approximately equivalent to that of PET polyester fiber.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

dissolving acetate fibers into an organic solvent, wherein the organic solvent comprises one of but not limited to acetone, NMMO and DMAP, the acetate fibers comprise one or more of but not limited to monoacetate fibers, diacetate fibers and triacetate fibers, and CDA (diacetate fibers) is preferred; adding organic weak base, wherein the organic weak base comprises triethylamine and ammonia water, and adjusting the pH value of the solution to 8-12 to obtain an acetate solution;

stirring and heating an acetate solution, adding a modifier and polyethylene glycol in the process, wherein the modifier is one or the combination of poly-bis-Schiff base and dopamine, the poly-bis-Schiff base is used for rapidly carrying out cross-linking reaction with free hydroxyl in a molecular structure of the acetate fiber to achieve the purpose of modification, and the dopamine has strong adsorbability, can strongly adsorb and wrap the acetate fiber and is used for carrying out surface treatment modification on the acetate fiber; continuously stirring until a pulling and hanging state appears, and cooling to obtain a wet spinning solution;

the wet spinning solution is spun by a spinneret to obtain the high-strength acetate fiber, wherein the spinneret is one of 28 holes/0.040 mm and 28 holes/0.060 mm, and parameters of the spinneret are determined according to the type of the modifier.

Example one

100g CDA was dissolved in 500mL acetone, and the mixture was stirred thoroughly under a sealed condition for 24 hours until the cellulose acetate was dissolved into a transparent liquid. Triethylamine was added and the pH of the solution was adjusted to 8. Under continuous stirring, the solution is heated to 100 ℃ by water bath and boiled, poly bis-Schiff base 0.2g [ phi ], [ PhCH2N = C = NCH2Ph ], [ n ], [ 2g ] polyethylene glycol is added, and the reflux reaction is continued until the state of drawing and hanging silk appears. The reaction is continued for 24 hours to obtain a crosslinking acetate fiber wet spinning solution, a spinneret plate with 28 holes/0.040 mm is used for spinning acetate fiber in wet spinning, high-strength acetate fiber with the dry strength of 2.2-2.6eN/dtex and the fracture growth rate of 25-27 percent (25 ℃) can be obtained, the softening temperature of the acetate fiber is 220-225 ℃, and the softening temperature of the acetate fiber is approximately equivalent to that of PET polyester fiber.

The dosage of the poly-bis-Schiff base is 0.1-1g, and 0.2g is a specific example; the amount of polyethylene glycol used is specifically exemplified by 1 to 9g and 2g.

The continuous stirring reaction time for adding the poly-bis-Schiff base is 8 to 24 hours

The molecular formula of the poly-bis-schiff base is [ R1N = C = NR2] N, wherein R1 and R2 are one or a combination of any two or more of saturated and unsaturated aliphatic chains, aromatic rings and heterocyclic rings, and preferably, R1 and R2 are phenyl and simple alkane substitutes thereof, as mentioned above as a specific example.

The crosslinking principle of the poly-bis-Schiff base and the cellulose acetate fiber is as follows:

the modified acetate fibers can be used in a variety of applications including, but not limited to, textile fibers, cigarette filters, and film products.

Example two

100g of monoacetate fiber is dissolved in 500mL of acetone solvent, and the solution is sealed and fully stirred for 24 hours until the acetate fiber is dissolved into transparent liquid. Ammonia was added to adjust the pH of the solution to 12. And heating the solution to 50 ℃ in a water bath under full stirring, adding 4g of dopamine and 2g of polyethylene glycol, and continuously stirring until a wire drawing and hanging state appears. Stirring was continued for 8 hours and then cooled to room temperature and a homogeneous brown viscous wet spinning solution was formed. The obtained polydopamine modified acetate fiber wet spinning solution is directly used for spinning, a spinneret plate with 28 holes/0.060 mm is used for spinning acetate fiber, high-strength acetate fiber with the dry strength of 1.8-2.0eN/dtex and the breaking growth rate of 30-35% (25 ℃) can be obtained, the softening temperature of the acetate fiber is 200-215 ℃, and the softening temperature of the acetate fiber is approximately equivalent to that of PET polyester fiber.

The dosage of polyethylene glycol is 1-9g and 2g as specific examples; the amount of dopamine used is specifically exemplified by 0.1 to 5g, and 4g.

The reaction time with continuous stirring with dopamine addition ranged from 8 to 24 hours.

The modified acetate fibers can be used in a variety of applications including, but not limited to, textile fibers, cigarette end filters, and film products.

EXAMPLE III

100g of triacetate fiber is dissolved in 500mL of acetone solvent, and the mixture is sealed and stirred sufficiently for 24 hours until the triacetate fiber is dissolved into a transparent liquid. Triethylamine was added and the pH of the solution was adjusted to 10. The solution is heated to 100 ℃ by water bath under full stirring, 0.2g of poly-bis-Schiff base [ PhCH2N ] = C = NCH2Ph ] ]n,2g of polyethylene glycol are added, and the reflux reaction is continued until the state of drawing and hanging filaments appears. After the continuous reaction is carried out for 24 hours, the temperature is reduced to 50 ℃,4g of dopamine is added, the continuous reaction is carried out for 24 hours, and then the blended and cross-linked modified acetate fiber wet spinning solution can be obtained, a 28-hole/0.040 mm spinneret plate is used for spinning the acetate fiber, so that the high-strength acetate fiber with the dry strength of 2.6-2.9eN/dtex and the fracture growth rate of 32-35% (25 ℃) can be obtained, the softening temperature of the acetate fiber is 225-230 ℃, and the softening temperature of the acetate fiber is approximately equivalent to that of PET polyester fiber.

The dosage of the poly-bis-Schiff base is 0.1-1g, and 0.2g is a specific example; the dosage of the polyethylene glycol is 1-9g, and the dosage of the polyethylene glycol is specifically exemplified; the amount of dopamine used is specifically exemplified by 0.1 to 5g, and 4g.

The reaction time of adding dopamine under continuous stirring is 8-24 hours, and the reaction time of adding poly-bis-schiff base under continuous stirring is 8-24 hours.

The poly-bis-schiff base has a molecular formula of [ R1N = C = NR2] N, wherein R1 and R2 are one or a combination of any two or more of a saturated and unsaturated aliphatic chain, an aromatic ring and a heterocyclic ring, preferably, R1 and R2 are phenyl and a simple alkane substituent thereof, and the above is a specific example.

Example four

20g CDA was dissolved in 200ml of MMO (N-methylmorpholine aqueous solution, methylmorpholine oxide) solvent, and the mixture was stirred thoroughly under a closed condition for 24 hours until the cellulose acetate was dissolved into a transparent liquid. Triethylamine was added and the pH of the solution was adjusted to 8.5. Heating the solution to 100 ℃ by a water bath under full stirring, adding 0.2g of bis-Schiff base PhCH2N = C = NCH2Ph and 2g of polyethylene glycol, and continuously carrying out reflux reaction until the filament drawing state appears. After the continuous reaction is carried out for 24 hours, the temperature is reduced to 50 ℃,4g of dopamine is added, the continuous reaction is carried out for 24 hours, and then the blending and crosslinking modified acetate fiber wet spinning solution can be obtained, a spinneret plate with 28 holes/0.060 mm is used for spinning the acetate fiber in the wet spinning process, so that the high-strength acetate fiber with the dry strength of 2.5-2.7eN/dtex and the fracture growth rate of 25-30 percent (25 ℃) can be obtained, the softening temperature of the acetate fiber is 215-220 ℃, and the softening temperature of the acetate fiber is approximately equivalent to that of PET polyester fiber.

The dosage of the bis-Schiff base is 0.1-1g, and 0.2g is a specific example; the dosage of the polyethylene glycol is 1-9g, and the dosage of the polyethylene glycol is specifically exemplified; the amount of dopamine used is specifically exemplified by 0.1 to 5g, and 4g.

The continuous stirring reaction time range of adding dopamine is 8-24 hours, and the continuous stirring reaction time range of adding poly-bis-Schiff base is 8-24 hours

The formula of the bis-schiff base is R1N = C = NR2, wherein R1 and R2 are one or a combination of any two or more of saturated and unsaturated aliphatic chains, aromatic rings and heterocyclic rings, preferably R1 and R2 are phenyl and simple alkane substitutes thereof, and the above is a specific example.

The crosslinking principle of the bis-Schiff base and the cellulose acetate is as follows:

EXAMPLE five

20g of CDA is dissolved in 200ml of DMAMAP (4-dimethylaminopyridine) solvent, and the mixture is fully stirred for 24 hours in a closed state until cellulose acetate is dissolved into transparent liquid. Ammonia was added to adjust the pH of the solution to 8.5. Heating the solution to 100 ℃ by water bath under full stirring, adding 0.2g of bis-Schiff base PhCH2N = C = NCH2Ph and 2g of polyethylene glycol, and continuously performing reflux reaction until a wire drawing and hanging state occurs. After the continuous reaction is carried out for 24 hours, the temperature is reduced to 50 ℃,4g of dopamine is added, the continuous reaction is carried out for 24 hours, and then the blending and crosslinking modified acetate fiber wet spinning solution can be obtained, a spinneret plate with 28 holes/0.060 mm is used for spinning the acetate fiber in the wet spinning process, so that the high-strength acetate fiber with the dry strength of 1.8-2.2eN/dtex and the fracture growth rate of 25-30 percent (25 ℃) can be obtained, the softening temperature of the acetate fiber is 215-220 ℃, and the softening temperature of the acetate fiber is approximately equivalent to that of PET polyester fiber.

In practical applications, the above examples illustrate the apparatus and general procedure used for fiber performance testing:

* Determination of the fiber properties: the GB/T14337-2008 standard is adopted, and an experimental YG001D type electronic single fiber strength tester produced by Wen Zhouji Gao Jia instrumentation company is used. About 500 fibers are randomly taken out from a laboratory, evenly laid on a wool board for later use, one fiber is randomly taken out by a pair of tweezers, one end of the fiber is fixed by a tension clamp and placed in a holder of an instrument to ensure that the fiber is axially extended, the pre-tension is 0.12cN/dtex when the fiber is used, the nominal gauge length is 10mm, and the experimental breaking value is read at the stretching speed of 10 mm/min. The samples were repeated 50 times and averaged.

* Measurement of fiber softening temperature: DSC3+ was produced by the company METTLER TOLEDO. The softening and crystallization temperatures were observed under a nitrogen atmosphere (50.0 mL/min), with a heat-up rate of 10.00K/min, with the sample heated from 30.0 to 300.0 degrees Celsius, and then returned from 300.0 to 30.0 degrees Celsius at 2.00K/min.

The invention has the beneficial effects that: the invention modifies the blending and copolymerization of acetate fibers by using dopamine and highly reactive cross-linked polymers [ R1N = C = NR2] N (polycarbodiimide or poly bis-Schiff base), respectively. The acetate fiber is wrapped by strong dopamine adsorption, and is treated and modified on the surface of the acetate fiber, and the poly bis-Schiff base cross-linked polymer has high activity and is easy to generate nucleophilic addition of affinity functional groups such as carboxyl, amino, hydroxyl and water, and is widely applied to polylactic acid and polyurethane cross-linking tackifying reaction. In the patent, the purpose of modification is achieved by utilizing the fact that free hydroxyl groups exist in the molecular structure of the cellulose acetate fiber and the cellulose acetate fiber rapidly undergo a crosslinking reaction. The cellulose acetate modified by the poly-bis-Schiff base has the advantages that the tensile strength and the durability (wear resistance) of the cellulose acetate are effectively improved, and the thermal stability of the cellulose acetate is greatly improved. The modified acetate fiber can be dissolved into spinning solution by a conventional solvent method and then can be subjected to wet spinning. In the patent, the addition amounts of dopamine and poly-bis-Schiff base are small, and the production cost of acetate fibers is not increased basically. The dopamine can effectively coat the outer layer, and the poly-bis-Schiff base is subjected to cross-linking polymerization, so that the poly-bis-Schiff base not only is on the surface of the acetate fiber, but also changes the internal structure of the acetate fiber, and finally has great influence on the physical and mechanical properties of the fiber. The two-step modification method of the chemical acetate fiber and the physical acetate fiber can not reduce the solubility of the modified acetate fiber in a common solvent, thereby obtaining the acetate fiber with high strength performance without changing the wet spinning process. The high-strength acetate fiber with the dry strength of 1.8-2.9 eN/dtex and the fracture growth rate of 25-35 percent at 25 ℃ can be obtained, and the softening temperature of the acetate fiber is 200-230 ℃ which is approximately equivalent to that of PET polyester fiber.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. The preparation method of the high-strength acetate fiber is characterized by comprising the following steps:

dissolving acetate fiber in an organic solvent to obtain an acetate solution;

adding a modifier and polyethylene glycol into an acetate solution to obtain a wet spinning solution, wherein the modifier is one or a combination of two of poly-bis-Schiff base and dopamine, the molecular formula of the poly-bis-Schiff base is [ R1N = C = NR2] N, and R1 and R2 are one or a combination of more than two of saturated and unsaturated aliphatic chains, aromatic rings and heterocyclic rings;

2. The method for preparing the high-strength acetate fiber according to claim 1, wherein the acetate fiber includes one or more of monoacetate fiber, diacetate fiber and triacetate fiber.

3. The method of claim 1, wherein the dissolving of the acetate fiber in an organic solvent to obtain an acetate solution comprises: dissolving acetate fiber in an organic solvent, adding an organic weak base, and adjusting the pH value of the solution to 8-12 to obtain an acetate solution.

4. The method of claim 3, wherein the organic solvent comprises one of acetone, NMMO, and DMAP.

5. The method for preparing high-strength acetate fibers according to claim 3, wherein the weak organic base comprises triethylamine and ammonia water.

6. The method for preparing the high-strength acetate fiber according to claim 1, wherein the step of adding the modifier and the polyethylene glycol to the acetate solution to obtain a wet spinning solution comprises: stirring and heating the acetate solution, adding a modifier and polyethylene glycol in the process, continuously stirring until a drawing and hanging state occurs, and cooling to obtain a wet spinning solution.

7. The method for preparing high-strength acetate fibers according to claim 1, wherein the reaction temperature of the poly-bis-schiff base is 100 ℃ and the reaction temperature of the dopamine is 50 ℃.

8. The method of claim 1, wherein the spinneret plate is one of 28 holes/0.040 mm and 28 holes/0.060 mm.