CN112921431A - Preparation method of microporous polyvinyl alcohol fibers - Google Patents
Preparation method of microporous polyvinyl alcohol fibers Download PDFInfo
- Publication number
- CN112921431A CN112921431A CN201911231764.0A CN201911231764A CN112921431A CN 112921431 A CN112921431 A CN 112921431A CN 201911231764 A CN201911231764 A CN 201911231764A CN 112921431 A CN112921431 A CN 112921431A
- Authority
- CN
- China
- Prior art keywords
- polyvinyl alcohol
- fiber
- solution
- microporous
- spinning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/14—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of unsaturated alcohols, e.g. polyvinyl alcohol, or of their acetals or ketals
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/06—Wet spinning methods
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/24—Formation of filaments, threads, or the like with a hollow structure; Spinnerette packs therefor
- D01D5/247—Discontinuous hollow structure or microporous structure
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/04—Chemical after-treatment of artificial filaments or the like during manufacture of synthetic polymers
- D01F11/06—Chemical after-treatment of artificial filaments or the like during manufacture of synthetic polymers of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Artificial Filaments (AREA)
Abstract
The invention discloses a preparation method of microporous polyvinyl alcohol fibers, which comprises the following steps of preparing a spinning solution, a sodium sulfate solution and a calcium hydroxide solution; step two, cooling the spinning solution to 40-60 ℃, and adding a foaming agent to obtain a polyvinyl alcohol spinning stock solution; spinning, namely feeding the spun fiber into a sodium sulfate solution, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain a polyvinyl alcohol nascent fiber; reacting with a calcium hydroxide solution to obtain secondary fibers; step five, heating the secondary fibers for foaming; and step six, stretching, cleaning and drying to obtain a finished product of the microporous polyvinyl alcohol fiber. The invention can increase the specific surface area of the microporous polyvinyl alcohol fiber; calcium sulfate or calcium carbonate formed by the reaction and hydroxyl on a polyvinyl alcohol molecular chain form strong interaction to limit the movement of the molecular chain, so that the microporous polyvinyl alcohol fiber has good dimensional stability; and the residue of sodium sulfate is effectively reduced, thereby being beneficial to the application of the sodium sulfate in medical aspect.
Description
Technical Field
The invention relates to the technical field of polyvinyl alcohol preparation, in particular to a preparation method of microporous polyvinyl alcohol fibers.
Background
The polyvinyl alcohol fiber has the characteristics of high strength, high modulus, wear resistance, acid and alkali resistance and good weather resistance, and is non-toxic, pollution-free, harmless to human skin and harmless to human body, so that the polyvinyl alcohol fiber is not only widely applied to building materials, but also widely applied to medical materials. However, polyvinyl alcohol fibers have the disadvantages of poor dimensional stability and significant shrinkage upon contact with water. At present, in order to improve the dimensional stability and water shrinkage of polyvinyl alcohol fibers, a filler is generally added in the process of dissolving or melting the polyvinyl alcohol resin.
However, direct filler addition suffers from different specific gravities, often resulting in precipitation phenomena; particularly, the additive is added into spinning solution, so that the phenomenon of hole blockage of a spinneret plate often occurs.
In the traditional production process of the polyvinyl alcohol fiber, the fiber formed after spinning is firstly dehydrated by adopting a sodium sulfate solution in a coagulating bath, then is cleaned and finally is dried. In the conventional wet spinning process of polyvinyl alcohol fiber, a sodium sulfate solution is usually used to rapidly dehydrate a polyvinyl alcohol stock solution, i.e. a coagulating bath treatment. Sodium sulfate remains on the surface and inside of the polyvinyl alcohol fibers treated with the coagulating bath of the sodium sulfate solution.
Because the sodium sulfate which is a strong electrolyte is used as a coagulating bath treatment substance of the fiber formed by spinning the polyvinyl alcohol spinning solution, the water absorption of the sodium sulfate can quickly remove the water on the surface of the polyvinyl alcohol fiber due to the water absorption of the polyvinyl alcohol fiber, the effect of removing the water in the polyvinyl alcohol fiber is relatively weak, so that the surface of the polyvinyl alcohol fiber is compact, the interior of the polyvinyl alcohol fiber is loose, an obvious skin-core structure is formed, the polyvinyl alcohol fiber with the skin-core structure has stronger mechanical property, but the intermolecular force of the skin layer with compact surface is stronger, so that-OH of the side chain of the polyvinyl alcohol fiber is greatly limited, and finally, the hydrophilic capability of the polyvinyl alcohol fiber is greatly reduced, the medical material needs better hydrophilicity, so the polyvinyl alcohol fiber prepared by the method is greatly limited in the medical field.
The surface and the interior of the polyvinyl alcohol fiber prepared by the process contain more sodium sulfate, and the sodium sulfate is strong electrolyte and is easy to damage human bodies after contacting with skin, so that the polyvinyl alcohol fiber cannot be applied to damaged skin or wounds, and the application of the polyvinyl alcohol fiber in the field of medical materials is limited.
In conclusion, the polyvinyl alcohol fiber prepared by the traditional process cannot be applied to the field of medical materials.
Disclosure of Invention
The invention aims to provide a preparation method of microporous polyvinyl alcohol fibers, which ensures that the prepared microporous polyvinyl alcohol fibers not only have good mechanical properties, but also have excellent hydrophilic properties, and also greatly reduces the content of sodium sulfate on the surfaces and in the microporous polyvinyl alcohol fibers, so that the microporous polyvinyl alcohol fibers have low irritation to skin or wounds, and are suitable for the field of medical materials.
In order to achieve the purpose, the invention provides the following technical scheme:
a preparation method of microporous polyvinyl alcohol fibers comprises the following steps:
step one, preparing a spinning solution: mixing raw material polyvinyl alcohol resin with water, and heating until the raw material polyvinyl alcohol resin is completely dissolved to form a spinning solution;
preparing a calcium hydroxide solution: mixing calcium hydroxide powder with water to form a calcium hydroxide solution;
preparing a sodium sulfate solution: sodium sulfate solution with concentration of 35% formed by mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 40-60 ℃, and adding a foaming agent to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: spinning the polyvinyl alcohol spinning stock solution obtained in the step two, allowing the spun fiber to enter a sodium sulfate solution for first coagulation bath treatment, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain a polyvinyl alcohol nascent fiber;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber obtained in the third step with a calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: heating the secondary raw fiber obtained in the fourth step for foaming, and stretching to form a primary finished product of the microporous polyvinyl alcohol fiber;
step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber;
the foaming agent is one of ammonium carbonate and ammonium bicarbonate.
Through the technical scheme: in the first step, the spinning solution, the calcium hydroxide solution and the sodium sulfate solution are respectively prepared completely for later use, on one hand, the subsequent operation is convenient and the whole operation is continuous, and on the other hand, the purity degree of the prepared solution is increased, and the influence on the preparation effect caused by the introduction of other impurities is reduced.
And in the second step, the spinning solution is cooled to 40-60 ℃ to be in a slight gel state, and at the moment, ammonium bicarbonate or ammonium carbonate serving as a foaming agent is added and mixed with the spinning solution in the slight gel state to form a polyvinyl alcohol spinning stock solution. The temperature at this time is not high enough to decompose the foaming agent and generate a large amount of gas, and therefore, the polyvinyl alcohol spinning dope can be maintained in a state of being kept.
In the third step, the polyvinyl alcohol spinning solution is first spun through a spinneret plate, and the spun fiber enters the sodium sulfate solution immediately. It should be noted that, since the whole preparation process is carried out continuously, the concentration of the sodium sulfate solution needs to be maintained at 35% in order to achieve a better dehydration effect in the first coagulation bath treatment in the third step.
When the foaming agent is ammonium bicarbonate, the sprayed fiber contains the ammonium bicarbonate inside and on the surface of the fiber, and the ammonium bicarbonate on the surface of the fiber reacts with sodium sulfate to form sodium bicarbonate and ammonium sulfate; when the foaming agent is ammonium carbonate, the interior and the surface of the sprayed fiber contain ammonium carbonate, and part of the foaming agent reacts with sodium sulfate to form sodium carbonate and ammonium sulfate, so that the content of the sodium sulfate is reduced, the adhesion of the sodium sulfate on the formed polyvinyl alcohol nascent fiber is favorably reduced, and the adverse effect on the subsequent operation is also reduced. Furthermore, the operation is also beneficial to reducing the pollution of sodium sulfate to the environment and reducing the difficulty of water treatment.
When the foaming agent is ammonium bicarbonate, the reaction formula is as follows:
2NH4HCO3+Na2SO4＝2NaHCO3+(NH4)2SO4；
when the foaming agent is ammonium carbonate, the reaction formula is as follows:
(NH4)2CO3+Na2SO4＝Na2CO3+(NH4)2SO4。
in the fourth step, the calcium hydroxide is used in excess, and when the calcium hydroxide solution is adopted to react with the ammonium sulfate generated in the third step, the pure and impurity-free calcium sulfate is generated. Therefore, whether the foaming agent is ammonium bicarbonate or ammonium carbonate, the following reaction formula can occur in the fourth step:
Ca(OH)2+(NH4)2SO4＝CaSO4+2NH3↑+2H2O。
meanwhile, when the foaming agent is ammonium carbonate, sodium carbonate generated by the reaction of the ammonium carbonate and sodium sulfate and calcium hydroxide form calcium carbonate.
The calcium sulfate or calcium carbonate can limit the movement of molecular chains by forming stronger interaction with hydroxyl on the molecular chains of the polyvinyl alcohol fibers, and simultaneously bind plasticizer molecules, so that the size shrinkage and expansion phenomena of the polyvinyl alcohol fibers are reduced, and the mechanical property and the size stability of the polyvinyl alcohol fibers are improved.
In contrast, if calcium sulfate is directly added to polyvinyl alcohol fibers, the calcium sulfate is precipitated due to the high specific gravity of the calcium sulfate, and the calcium sulfate added is not uniformly dispersed, so that the calcium sulfate cannot be uniformly combined with the nascent fibers. And if the calcium sulfate is directly added, the purity of the added calcium sulfate is influenced. The preparation method of sodium sulfate is various, but most of the preparation methods still have more by-products or impurities, so that the purity of calcium sulfate is influenced. In the application, substances added in all the steps are high in purity, and the treated polyvinyl alcohol resin does not produce other byproducts, so that calcium sulfate formed by final reaction has high purity and plays a key role in improving the mechanical property of the finally obtained microporous polyvinyl alcohol fiber.
In the reaction process of the present application, sodium bicarbonate and ammonium sulfate can be generated by the reaction of a foaming agent ammonium bicarbonate and sodium sulfate, or sodium carbonate and ammonium sulfate can be generated by the reaction of a foaming agent ammonium carbonate and sodium sulfate. The preparation method is carried out to the end of the fourth step, and the obtained secondary fiber contains ammonia gas, carbon dioxide gas, a foaming agent (ammonium bicarbonate or ammonium carbonate) and sodium bicarbonate or sodium carbonate formed by reaction. After the heating treatment in the step five, a foaming agent (ammonium bicarbonate or ammonium carbonate) and sodium bicarbonate or sodium carbonate formed by the reaction generate a large amount of bubbles, so that a large amount of micropores are formed in the formed primary microporous polyvinyl alcohol fiber finished product; meanwhile, along with a foaming agent (ammonium bicarbonate or ammonium carbonate), a large amount of bubbles generated by sodium bicarbonate or sodium carbonate formed by reaction, ammonia gas and carbon dioxide escape from the secondary fiber, a large amount of micropores can be formed on the surface of the primary microporous polyvinyl alcohol fiber product, and finally, a large amount of micropores can be formed in the interior and on the surface of the obtained primary microporous polyvinyl alcohol fiber product, so that the hydrophilicity of the primary microporous polyvinyl alcohol fiber product is effectively improved. Meanwhile, a large number of micropores are formed on the surface of the primary microporous polyvinyl alcohol fiber product, compared with the polyvinyl alcohol fiber prepared by the prior art, the mechanical property of the microporous polyvinyl alcohol fiber product is reduced, but the microporous polyvinyl alcohol fiber product is still better, and the requirement of medical materials on the mechanical strength of the polyvinyl alcohol fiber can be met. In addition, in the fifth step, although the sodium bicarbonate or sodium carbonate can be decomposed by heat to generate bubbles, the foaming effect is inferior to that of the ammonium bicarbonate, and due to the characteristics, the sodium bicarbonate or sodium carbonate is used as the foaming auxiliary agent of the ammonium bicarbonate foaming agent and the ammonium bicarbonate are cooperated to generate foaming effect in the foaming and pore-forming process in the fifth step, so that the foaming phenomenon is more continuous and more micropores are formed in the primary product of the microcellular polyvinyl alcohol fiber.
More preferably: the foaming agent in the second step is preferably ammonium bicarbonate.
Through the technical scheme: the ammonium bicarbonate is easier to be heated and decomposed, which is beneficial to generating bubbles and enables the formed primary product of the microporous polyvinyl alcohol fiber to have more micropores. And the ammonium bicarbonate, the sodium bicarbonate and the sodium carbonate are mutually matched, so that the effect of forming bubbles is continuously exerted.
More preferably: in the second step, the weight part ratio of the polyvinyl alcohol resin to the foaming agent is 1: (0.0003-0.001).
Through the technical scheme: and (3) limiting the weight part ratio range of the polyvinyl alcohol resin and the foaming agent, so that the primary finished product of the microporous polyvinyl alcohol fiber obtained after foaming and pore-forming in the step five has moderate number of micropores and large specific surface area of a micropore structure, and the breaking strength of the primary finished product of the microporous polyvinyl alcohol fiber is too low.
When the using amount of the foaming agent is too large, too much foaming amount is easily caused, the breaking strength of a primary finished product of the microporous polyvinyl alcohol fiber is reduced, and the spinning is difficult; when the amount of the blowing agent used is too small, the amount of the blowing agent tends to be small, and the specific surface area is restricted although the breaking strength of the fiber is increased, resulting in poor dimensional stability.
More preferably: in the second step, the weight part ratio of the polyvinyl alcohol resin to the foaming agent is preferably 1: (0.0006-0.0009).
Through the technical scheme: tests show that when the weight part ratio of the polyvinyl alcohol resin to the foaming agent is 1: (0.0006-0.0009), the finally obtained microporous polyvinyl alcohol fiber finished product has a microporous structure with excellent breaking strength and large specific surface area.
In the third step, the temperature of the first coagulating bath treatment is 35-55 ℃, and the treatment speed of the first coagulating bath treatment is 7-9 m/s.
Through the technical scheme: the prepared sodium sulfate solution is adopted in the first coagulating bath treatment, and the key component of the sodium sulfate solution is sodium sulfate, so that the dissolution of the sodium sulfate component in the sodium sulfate solution is facilitated and the concentration of the sodium sulfate solution is more uniform under the condition that the treatment temperature is 35-55 ℃. The polyvinyl alcohol nascent fiber obtained by the first coagulating bath treatment has a good dehydration effect and good dimensional stability.
In the third step, the temperature of the first coagulation bath treatment is preferably 40-50 ℃, and the treatment speed of the first coagulation bath treatment is preferably 7 m/s.
Through the technical scheme: the research shows that in the temperature range, the combination of the processing speed helps to ensure that the treated polyvinyl alcohol nascent fiber has better dehydration effect and dimensional stability.
More preferably: in the first step, the weight part ratio of water to calcium hydroxide is 1: (0.006-0.02).
Through the technical scheme: calcium hydroxide can have stronger penetrating power without heating, and the calcium hydroxide is added in the second coagulation bath treatment in the fourth step in the application and reacts with the ammonium sulfate reacted in the third step to generate calcium sulfate, ammonia and water. The generated calcium sulfate can directly act on the surface of the secondary fiber, so that the dimensional stability of the secondary fiber is improved.
More preferably: in the fourth step, the weight part ratio of water to calcium hydroxide is preferably 1: (0.011-0.014).
Through the technical scheme: researches show that the secondary fiber obtained by the treatment of the second coagulating bath has better mechanical property by adopting the weight part ratio range of the water and the calcium hydroxide.
More preferably: in the fifth step, the mixture is heated to 180-250 ℃ for foaming, and the conveying speed of the secondary fibers is 30-40 m/s.
Through the technical scheme: because the existing polyvinyl alcohol wet spinning production is in the secondary fiber subsequent process, the drying tunnel is heated and stretched, the temperature of the drying tunnel is between 180 ℃ and 250 ℃, namely in the step five, the temperature is utilized to decompose the ammonium bicarbonate and the sodium bicarbonate which are not completely reacted and remain in the secondary fiber into NH through heating3And CO2And then the polyvinyl alcohol fiber escapes from the secondary fiber, and micropores are left on the secondary fiber, so that a primary product of the microporous polyvinyl alcohol fiber is obtained. The method utilizes the original heating procedure of drying the secondary fibers in the drying tunnel, does not need to be additionally heated, not only saves energy consumption, but also can achieve the purpose of fully decomposing residual hydrogen carbonateThe primary finished product of the microporous polyvinyl alcohol fiber contains more micropores under the action of ammonium and sodium bicarbonate.
More preferably: in the fifth step, the temperature for foaming is preferably 220-230 ℃.
Through the technical scheme: the temperature range can lead the foaming agent to be subjected to full thermal decomposition, promote the foaming agent to generate bubbles, lead the obtained primary finished product of the microporous polyvinyl alcohol fiber not to have residual foaming agent, and be beneficial to removing the possible residual taste of the foaming agent; and the temperature of the drying tunnel in the traditional process is 220-.
In conclusion, the invention has the following beneficial effects:
firstly, the invention adopts a specific treatment method combining the first coagulation bath by adding a foaming agent-sodium sulfate into a spinning solution and the second coagulation bath by adding calcium hydroxide, cleaning and drying, so that the content of sodium sulfate in a system after reaction is greatly reduced, the residue of the sodium sulfate on the surface of the finally obtained microporous polyvinyl alcohol fiber is favorably reduced, and the limitation of the microporous polyvinyl alcohol fiber on the aspect of medical application is reduced.
The second and traditional process is as follows: foaming-dewatering by coagulating bath treatment with sodium sulfate-washing-drying, in the conventional process, washing the residual mirabilite on 1 ton of microporous polyvinyl alcohol fiber consumes about 10 tons of water; by adopting the preparation method, the added sodium sulfate is basically reacted, so that only 2.5 tons of microporous polyvinyl alcohol fibers are needed for cleaning 1 ton of microporous polyvinyl alcohol fibers, the water consumption is greatly saved, and only trace amount of sodium sulfate is contained in the cleaned water, so that the preparation method is favorable for environmental protection and sustainable development.
Thirdly, the foaming agent adopted in the invention is added under the condition of low temperature without decomposition, the foaming agent appears in the interior and on the surface of the polyvinyl alcohol primary fiber through the spinning action, the foaming agent on the surface can react with sodium sulfate to reduce the content of the sodium sulfate, and auxiliary components (sodium bicarbonate and sodium carbonate) which can be thermally decomposed to form gas are formed through the reaction, and the heating operation in the fifth step causes the foaming agent in the interior of the secondary fiber and the sodium bicarbonate and sodium carbonate on the surface of the secondary fiber to be thermally decomposed to form bubbles, so that the secondary fiber forms uniform micropores from inside to outside, and the finally obtained microporous polyvinyl alcohol fiber finished product has larger specific surface area. Meanwhile, after the preparation process of the foaming agent adopted in the application is finished, toxic and harmful substances are not easy to remain, and side reaction on the polyvinyl alcohol resin is avoided.
Fourthly, the invention adopts a processing method combining the first coagulation bath carried out by adding a foaming agent-sodium sulfate into a spinning solution and the second coagulation bath carried out by calcium hydroxide, cleaning and drying, wherein the foaming agent reacts with sodium sulfate to form a product, and then the product reacts with calcium hydroxide to form pure calcium sulfate which is attached to the surface of formed secondary fibers, and even if foaming is carried out in the later period, the product is not easy to separate from the fibers, and the finally obtained finished product of the microporous polyvinyl alcohol fibers has better dimensional stability and mechanical property.
Drawings
FIG. 1 is a flow chart of the manufacturing process of the present invention.
FIG. 2 is a Scanning Electron Micrograph (SEM) of a microvoided polyvinyl alcohol fiber structure.
The specific implementation mode is as follows:
the present invention will be described in further detail with reference to the following drawings and examples.
Example 1: a preparation method of microporous polyvinyl alcohol fibers comprises the following steps:
step one, preparing a spinning solution: adding 180kg of 2499-grade polyvinyl alcohol resin and 820kg of water into a dissolving kettle, slowly stirring at a stirring speed of 40rpm, and heating to 95 ℃ until the polyvinyl alcohol resin is completely dissolved to form a spinning solution; preparing a calcium hydroxide solution: calcium hydroxide powder and water are mixed according to the weight ratio of 0.0125: 1 to form a calcium hydroxide solution;
preparing a sodium sulfate solution: forming sodium sulfate solution with the concentration of 35% by using mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 60 ℃, adding 126g of ammonium bicarbonate as a foaming agent, keeping the stirring speed of 40rpm, pressurizing the kettle to 0.3MPa, and continuously stirring for 30min to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: conveying the polyvinyl alcohol spinning stock solution obtained in the step two to a spinneret plate through a pipeline, enabling the spun fibers to enter a sodium sulfate solution for first coagulation bath treatment, enabling the temperature of the first coagulation bath treatment to be 40 ℃, enabling the treatment speed of the first coagulation bath treatment to be 7m/s, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain polyvinyl alcohol nascent fibers;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber obtained in the third step with an excessive calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: introducing the secondary raw fiber obtained in the fourth step into a drying tunnel, keeping the temperature of the drying tunnel at 230 ℃, foaming, and simultaneously drawing the secondary raw fiber forwards at the speed of 35 m/min;
and step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber.
Example 2: a preparation method of microporous polyvinyl alcohol fibers comprises the following steps:
step one, preparing a spinning solution: adding 190kg of 1799-grade polyvinyl alcohol resin and 810kg of water into a dissolving kettle, slowly stirring at a stirring speed of 40rpm, and heating to 90 ℃ until the polyvinyl alcohol resin is completely dissolved to form a spinning solution; preparing a calcium hydroxide solution: calcium hydroxide powder and water are mixed according to the weight ratio of 0.0125: 1 to form a calcium hydroxide solution;
preparing a sodium sulfate solution: forming sodium sulfate solution with the concentration of 35% by using mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 41 ℃, adding 171g of ammonium bicarbonate as a foaming agent, keeping the stirring speed of 40rpm, pressurizing the kettle to 0.3MPa, and continuously stirring for 30min to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: conveying the polyvinyl alcohol spinning stock solution obtained in the step two to a spinneret plate through a pipeline, enabling the spun fibers to enter a sodium sulfate solution for first coagulation bath treatment, enabling the temperature of the first coagulation bath treatment to be 35 ℃, enabling the treatment speed of the first coagulation bath treatment to be 7m/s, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain polyvinyl alcohol nascent fibers;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber obtained in the third step with an excessive calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: introducing the secondary raw fiber obtained in the fourth step into a drying tunnel, keeping the temperature of the drying tunnel between 180 ℃, foaming, and simultaneously drawing the secondary raw fiber forwards at the speed of 35 m/min;
and step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber.
Example 3: a preparation method of microporous polyvinyl alcohol fibers comprises the following steps:
step one, preparing a spinning solution: adding 180kg of 2499-grade polyvinyl alcohol resin and 820kg of water into a dissolving kettle, slowly stirring at a stirring speed of 40rpm, and heating to 100 ℃ until the polyvinyl alcohol resin is completely dissolved to form a spinning solution;
preparing a calcium hydroxide solution: calcium hydroxide powder and water are mixed according to the weight ratio of 0.0065: 1 to form a calcium hydroxide solution;
preparing a sodium sulfate solution: forming sodium sulfate solution with the concentration of 35% by using mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 60 ℃, adding 126g of ammonium bicarbonate as a foaming agent, keeping the stirring speed of 40rpm, pressurizing the kettle to 0.3MPa, and continuously stirring for 30min to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: conveying the polyvinyl alcohol spinning stock solution obtained in the step two to a spinneret plate through a pipeline, enabling the spun fibers to enter a sodium sulfate solution for first coagulation bath treatment, enabling the temperature of the first coagulation bath treatment to be 55 ℃, enabling the treatment speed of the first coagulation bath treatment to be 8m/s, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain polyvinyl alcohol nascent fibers;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber obtained in the third step with an excessive calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: introducing the secondary raw fiber obtained in the fourth step into a drying tunnel, keeping the temperature of the drying tunnel between 250 ℃, foaming, and simultaneously drawing the secondary raw fiber forwards at a speed of 32 m/min; and step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber.
Example 4: a preparation method of microporous polyvinyl alcohol fibers comprises the following steps:
step one, preparing a spinning solution: adding 180kg of 2499-grade polyvinyl alcohol resin and 820kg of water into a dissolving kettle, slowly stirring at a stirring speed of 40rpm, and heating to 90 ℃ until the polyvinyl alcohol resin is completely dissolved to form a spinning solution; preparing a calcium hydroxide solution: calcium hydroxide powder and water are mixed according to the weight ratio of 0.019: 1 to form a calcium hydroxide solution;
preparing a sodium sulfate solution: forming sodium sulfate solution with the concentration of 35% by using mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 60 ℃, adding 126g of ammonium bicarbonate as a foaming agent, keeping the stirring speed of 40rpm, pressurizing the kettle to 0.3MPa, and continuously stirring for 30min to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: conveying the polyvinyl alcohol spinning stock solution obtained in the step two to a spinneret plate through a pipeline, enabling the spun fibers to enter a sodium sulfate solution for first coagulation bath treatment, enabling the temperature of the first coagulation bath treatment to be 50 ℃, enabling the treatment speed of the first coagulation bath treatment to be 9m/s, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain polyvinyl alcohol nascent fibers;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber obtained in the third step with an excessive calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: introducing the secondary raw fiber obtained in the fourth step into a drying tunnel, keeping the temperature of the drying tunnel between 220 ℃, foaming, and simultaneously drawing the secondary raw fiber forwards at a speed of 44 m/min;
and step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber.
Example 5: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 2 in that in the step one, 190kg of polyvinyl alcohol resin with the mark of 1799 and 810kg of water are added into a dissolving kettle when a spinning solution is prepared, and the mixture is slowly stirred at the stirring speed of 40rpm and heated to more than 90 ℃ until the polyvinyl alcohol resin is completely dissolved to form the spinning solution. And the amount of ammonium bicarbonate used in step two was 114 g.
Example 6: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, when a spinning solution is prepared, 180kg of 2499-grade polyvinyl alcohol resin and 820kg of water are added into a dissolving kettle, slowly stirred at a stirring speed of 40rpm and heated to above 90 ℃ until the polyvinyl alcohol resin is completely dissolved to form the spinning solution. And the amount of ammonium bicarbonate used in step two was 54 g.
Example 7: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, when a spinning solution is prepared, 180kg of 2499-grade polyvinyl alcohol resin and 820kg of water are added into a dissolving kettle, slowly stirred at a stirring speed of 40rpm and heated to above 90 ℃ until the polyvinyl alcohol resin is completely dissolved to form the spinning solution. And the amount of ammonium bicarbonate used in step two was 180 g.
Example 8: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, the weight part ratio of water to calcium hydroxide is 1: 0.006.
example 9: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, the weight part ratio of water to calcium hydroxide is 1: 0.02.
example 10: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, the weight part ratio of water to calcium hydroxide is 1: 0.011.
example 11: the preparation method of the microporous polyvinyl alcohol fiber is different from the embodiment 1 in that in the step one, the weight part ratio of water to calcium hydroxide is 1: 0.014.
example 12: a method for preparing microcellular polyvinyl alcohol fibers, which is different from example 1 in that ammonium carbonate is added as a foaming agent in the second step, and the amount of ammonium carbonate used is 144 g.
TABLE 1 parameters for examples 1-11
Comparative example 1: a method for preparing polyvinyl alcohol fibers, which is different from example 1 in that in the second step, 80g of ammonium bicarbonate is added.
Comparative example 2: a method for preparing polyvinyl alcohol fiber, which is different from that of example 1,
in the first step, when preparing the calcium hydroxide solution, mixing calcium hydroxide powder and water according to a weight ratio of 0.0031: 1, fully mixing;
in step two, the amount of ammonium bicarbonate added was 140 g.
Table 2 parameters of comparative example 1 and comparative example 2
Comparative example 3: a method of preparing polyvinyl alcohol fiber, which is different from example 1 in that ammonium bicarbonate is not added during the operation and 134g of sodium bicarbonate is used as a foaming agent.
Comparative example 4: a method for preparing polyvinyl alcohol fiber, which is different from the method of example 1 in that, in the operation process, calcium hydroxide solution is not used, and sodium hydroxide solution with equal concentration is used.
Comparative example 5: a method for preparing polyvinyl alcohol fiber, which is different from that of example 1,
no ammonium bicarbonate and calcium hydroxide solutions were added.
And (3) testing:
test reference standard: GB/T14335-2008, sodium sulfate residue is tested by a sintering weighing method.
The test instrument: muffle furnace, fiber length analyzer of chemical fiber fineness instrument, micronaire instrument, and YG008 type multifilament strengthener.
And (3) test results: the test results in the examples are shown in table 3; the test results in the comparative examples are shown in table 4.
Test results in the examples of Table 3
Table 4 test results in comparative examples
As is clear from tables 3 and 4, examples 1 to 11 had a foaming ratio of 19 to 21%, a shrinkage of 3%, a fiber breaking strength of 4.7 to 4.9cN/dtex, and a residual amount of sodium sulfate on the fiber of 0.0027 to 0.0029%.
Comparing comparative example 1 and examples 1 to 11, although the breaking strength was superior to that of examples 1 to 11, the foaming ratio in comparative example 1 was low and the residual amount of sodium sulfate on the fiber and the shrinkage rate were high, indicating that it was poor in hydrophilic property and not suitable for the field of medical materials. The main reasons for the above differences are: the comparative example 1 added an insufficient amount of ammonium bicarbonate, resulting in poor foaming effect, but since the same sodium sulfate solution as in examples 1 to 11 was used, and in the case of an insufficient amount of foaming agent, shrinkage thereof was more remarkable.
Comparing comparative example 2 and examples 1 to 11, the foaming ratio and the amount of sodium sulfate remaining on the fiber were similar to those of examples 1 to 11, but the shrinkage was too high and the breaking strength was too low, and although the polyvinyl alcohol fiber used as a medical material did not require too high breaking strength, it was difficult to satisfy the requirements in the field of medical materials with a breaking strength (1.2dtex) of only 2.1 cN/dtex. The main reasons for the above differences are: in comparative example 2, the amount of calcium hydroxide used was small, and the concentration of the formed calcium hydroxide solution was low, resulting in less calcium sulfate formed by the final reaction and less adhesion degree on the surface of the obtained polyvinyl alcohol fiber, and therefore, it was easier to make the polyvinyl alcohol fiber have poor dimensional stability, higher shrinkage rate, and lower breaking strength. Therefore, the concentration of the calcium hydroxide solution has a great influence on the mechanical properties and dimensional stability of the finally obtained polyvinyl alcohol fiber.
Compared with comparative example 3 and examples 1 to 11, the foaming ratio is low, the residual amount of sodium sulfate on the fiber is high, and the formed polyvinyl alcohol fiber has poor hydrophilicity and great damage to skin, so the polyvinyl alcohol fiber is not suitable for being applied to the field of medical materials. The main reasons for the above differences are: in comparative example 3, sodium bicarbonate was used as a foaming agent, and although the foaming effect was produced, the foaming effect was not as good as that of ammonium bicarbonate; and the polyvinyl alcohol fiber is difficult to react with sodium sulfate, and the sodium sulfate cannot be removed finally, so that more sodium sulfate still remains on the surface of the polyvinyl alcohol fiber. The ammonium bicarbonate or ammonium carbonate has better foaming effect and is beneficial to greatly reducing the content of residual sodium sulfate on the surface of the obtained polyvinyl alcohol fiber.
Comparing comparative example 4 with examples 1 to 11, the shrinkage was too high and the breaking strength was too low to satisfy the requirements in the field of medical materials. The main reasons for the above differences are: the sodium hydroxide solution used in comparative example 4 hardly forms a substance which adheres to the outer surface of the polyvinyl alcohol fiber and improves the mechanical properties thereof. The calcium sulfate and the calcium carbonate obtained by the reaction in the preparation process are beneficial to improving the breaking strength of the polyvinyl alcohol fiber.
Comparing comparative example 5 with examples 1 to 11, the polyvinyl alcohol obtained was poor in hydrophilicity and mechanical properties due to unfoamed, excessively high shrinkage, excessively low breaking strength, and residual amount of sodium sulfate on the fiber, and the skin was damaged when contacting the skin, which was difficult to satisfy the requirements in the field of medical materials. The main reasons for the above differences are: in comparative example 5, no ammonium bicarbonate and calcium hydroxide solutions were used. The mutual matching of ammonium bicarbonate and calcium hydroxide is shown to be beneficial to improving the foaming effect of the obtained polyvinyl alcohol fiber and increasing the hydrophilicity of the polyvinyl alcohol fiber, and is also beneficial to enabling the breaking strength to be moderate, so that the polyvinyl alcohol fiber is suitable for the field of medical materials.
The scanning electron microscope of the microporous polyvinyl alcohol fiber Structure (SEM) is shown in figure 2, and the figure shows that the foaming aperture is relatively consistent and the distribution is relatively uniform.
The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.
Claims (10)
1. A preparation method of microporous polyvinyl alcohol fibers is characterized by comprising the following steps:
step one, preparing a spinning solution: mixing raw material polyvinyl alcohol resin with water, and heating until the raw material polyvinyl alcohol resin is completely dissolved to form a spinning solution;
preparing a calcium hydroxide solution: mixing calcium hydroxide powder with water to form a calcium hydroxide solution;
preparing a sodium sulfate solution: sodium sulfate solution with concentration of 35% formed by mirabilite and water:
step two, preparing a polyvinyl alcohol spinning stock solution: cooling the spinning solution obtained in the step one to 40-60 ℃, and adding a foaming agent to obtain a polyvinyl alcohol spinning stock solution;
step three, spinning and first coagulating bath treatment: spinning the polyvinyl alcohol spinning stock solution obtained in the step two, allowing the spun fiber to enter a sodium sulfate solution for first coagulation bath treatment, and dehydrating a reaction product containing a foaming agent and mirabilite to obtain a polyvinyl alcohol nascent fiber;
step four, treating by a second coagulation bath: reacting the polyvinyl alcohol nascent fiber containing the reaction product of the foaming agent and the mirabilite with a calcium hydroxide solution to obtain a secondary fiber;
step five, foaming and pore forming: heating the secondary raw fiber obtained in the fourth step for foaming, and stretching to form a primary finished product of the microporous polyvinyl alcohol fiber;
step six, cleaning and drying the primary finished product of the microporous polyvinyl alcohol fiber obtained in the step five to obtain a finished product of the microporous polyvinyl alcohol fiber;
the foaming agent is one of ammonium carbonate and ammonium bicarbonate.
2. The method of claim 1, wherein the foaming agent in step two is preferably ammonium bicarbonate.
3. The method for preparing microcellular polyvinyl alcohol fibers according to claim 1, wherein in the second step, the weight part ratio of the polyvinyl alcohol resin to the foaming agent is 1: (0.0003-0.001).
4. The method for preparing microcellular polyvinyl alcohol fibers according to claim 3, wherein in the second step, the weight part ratio of the polyvinyl alcohol resin to the foaming agent is preferably 1: (0.0006-0.0009).
5. The method of claim 1, wherein the first coagulation bath treatment temperature is 35-55 ℃ and the first coagulation bath treatment speed is 7-9m/s in step three.
6. The method for preparing microporous polyvinyl alcohol fiber according to claim 5, wherein in the third step, the temperature of the first coagulation bath treatment is preferably 40-50 ℃, and the treatment speed of the first coagulation bath treatment is preferably 7 m/s.
7. The method for preparing microporous polyvinyl alcohol fiber according to claim 1, wherein in the first step, the weight ratio of water to calcium hydroxide is 1: (0.006-0.02).
8. The method for preparing microporous polyvinyl alcohol fiber according to claim 1, wherein in the fourth step, the weight ratio of water to calcium hydroxide is preferably 1: (0.011-0.014).
9. The method as claimed in claim 1, wherein in the step five, the heating is carried out to 180-250 ℃ for foaming, and the conveying speed of the secondary fiber is 30-40 m/s.
10. The method as claimed in claim 1, wherein in the step five, the temperature for foaming is preferably 220-230 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911231764.0A CN112921431A (en) | 2019-12-05 | 2019-12-05 | Preparation method of microporous polyvinyl alcohol fibers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911231764.0A CN112921431A (en) | 2019-12-05 | 2019-12-05 | Preparation method of microporous polyvinyl alcohol fibers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112921431A true CN112921431A (en) | 2021-06-08 |
Family
ID=76160807
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911231764.0A Withdrawn CN112921431A (en) | 2019-12-05 | 2019-12-05 | Preparation method of microporous polyvinyl alcohol fibers |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112921431A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111334884A (en) * | 2020-03-23 | 2020-06-26 | 浙江红雨医药用品有限公司 | Preparation method of microporous polyvinyl alcohol fibers |
| CN114672890A (en) * | 2022-04-15 | 2022-06-28 | 诸暨市天同化纤有限公司 | Preparation method of hollow microporous anti-fracture polyester POY (pre-oriented yarn) filament |
| CN115233328A (en) * | 2022-09-23 | 2022-10-25 | 中山大学 | Preparation method of superfine fluororubber fiber |
| US11624131B2 (en) | 2020-01-09 | 2023-04-11 | Zhejiang Hongyu Medical Commodity Co., Ltd. | Method for preparing microporous PVA fiber |
-
2019
- 2019-12-05 CN CN201911231764.0A patent/CN112921431A/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11624131B2 (en) | 2020-01-09 | 2023-04-11 | Zhejiang Hongyu Medical Commodity Co., Ltd. | Method for preparing microporous PVA fiber |
| CN111334884A (en) * | 2020-03-23 | 2020-06-26 | 浙江红雨医药用品有限公司 | Preparation method of microporous polyvinyl alcohol fibers |
| CN114672890A (en) * | 2022-04-15 | 2022-06-28 | 诸暨市天同化纤有限公司 | Preparation method of hollow microporous anti-fracture polyester POY (pre-oriented yarn) filament |
| CN114672890B (en) * | 2022-04-15 | 2023-02-07 | 诸暨市天同化纤有限公司 | Preparation method of hollow microporous anti-fracture polyester POY (pre-oriented yarn) filament |
| CN115233328A (en) * | 2022-09-23 | 2022-10-25 | 中山大学 | Preparation method of superfine fluororubber fiber |
| CN115233328B (en) * | 2022-09-23 | 2022-12-06 | 中山大学 | Preparation method of superfine fluororubber fiber |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111334884A (en) | Preparation method of microporous polyvinyl alcohol fibers | |
| CN112921431A (en) | Preparation method of microporous polyvinyl alcohol fibers | |
| JP7179099B2 (en) | Method for producing microporous polyvinyl alcohol fiber | |
| CN102527262B (en) | Method for preparing chemically perforated polyvinylidene fluoride hollow fiber ultrafiltration membrane | |
| EP0147634A2 (en) | Cellulose dope, process for preparation and method for application thereof | |
| CN106435830A (en) | High strength chitosan complex fiber and preparing method thereof | |
| CN104073907A (en) | Polyester fiber and preparation method thereof | |
| CN106591992B (en) | A kind of modified gelatin fiber | |
| CN111519280B (en) | Preparation method of chitosan fiber material | |
| CN111893580B (en) | Keratin spinning solution and prepared keratin regenerated fiber | |
| CN113355769B (en) | Hydroxylated alginic acid fiber and preparation method thereof | |
| CN107287697A (en) | A kind of preparation method of chitin fiber | |
| CN103556275A (en) | Far infrared bamboo charcoal viscose fiber and preparation method thereof | |
| CN114045575A (en) | Graphene sodium alginate composite hydrogel fiber and preparation method thereof | |
| CN107459637A (en) | Low molecule amount and the poly butylene succinate ionomer of high melt viscosity and its preparation and the microcellular foam material based on it and application | |
| CN108624972B (en) | Graphene/silicon compound, graphene/silicon compound/polyacrylonitrile composite fiber and preparation method thereof | |
| Zhang et al. | Preparation, characterization and properties of high-salt-tolerance sodium alginate/krill protein composite fibers | |
| CN108978336A (en) | A kind of paper grade (stock) softening agent and preparation method thereof | |
| WO1991009163A1 (en) | Modified viscose fibres and method for their manufacture | |
| JPH07189019A (en) | Production of regenerated cellulose formed product | |
| CN107935439A (en) | A kind of foaming agent combination and preparation method thereof | |
| CN113845672A (en) | Salix mongolica cellulose nanofiber, aerogel ball, preparation method and application | |
| CN107603281B (en) | Rapid preparation method of silane coupling agent modified white carbon black | |
| Yan et al. | Preparation of high-strength and high-toughness sodium alginate fibers based on the study of multi-ion diffusion kinetics in a low temperature dissolution system | |
| CN101649574B (en) | Method for recycling waste glassine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20210608 |
|
| WW01 | Invention patent application withdrawn after publication |