CN110373758B

CN110373758B - Flax spun yarn spinning process based on short flax raw material

Info

Publication number: CN110373758B
Application number: CN201910681538.6A
Authority: CN
Inventors: 陈韶娟; 邢晓露; 付冉冉
Original assignee: Qingdao University
Current assignee: Qingdao University
Priority date: 2019-07-26
Filing date: 2019-07-26
Publication date: 2021-06-25
Anticipated expiration: 2039-07-26
Also published as: CN110373758A

Abstract

The invention discloses a flax spun yarn spinning process based on a short flax raw material, which takes long flax as a raw material and comprises the following steps: (1) preparing strips; (2) drawing; (3) roving; (4) pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 0.5-7, the temperature of the water bath is set to be 20-100 ℃, and the time of the water bath treatment is 15-45 minutes; (5) spinning; (6) and final bleaching: the spun yarn bobbin is sleeved on a creel and is put into a boiling and bleaching pot, and the steps are carried out in the following sequence: the yarn quality is good, the end breakage rate is greatly reduced, and the obtained flax spun yarn fiber has gaps, so that the hand feeling is softer. The invention divides the difficult problems in the traditional boiling and bleaching and spinning process into rough yarn pre-bleaching and spun yarn final bleaching, and divides the difficult problem that the boiling and bleaching degree of the traditional rough yarn is difficult to control into two steps, thereby realizing the controllability of the process and ensuring the higher yarn quality of the flax spun yarn.

Description

Flax spun yarn spinning process based on short flax raw material

Technical Field

The invention relates to the field of flax spinning, in particular to a flax spun yarn spinning process based on a short flax raw material.

Background

Flax is used as an ecological textile raw material and is widely applied to producing high-grade fabrics. The textile containing the flax fiber not only has good air permeability, hygroscopicity and moisture desorption, but also has natural functions of antibiosis and health care, ultraviolet radiation resistance, noise reduction and wave absorption and the like, so that the textile is popular with people.

The flax finished yarn is divided into two types of long ramie spinning and short ramie spinning. At present, the domestic conventional flax short-staple spinning process mainly comprises the following steps: short hemp raw material → combing → strip making → drawing → roving → scouring and bleaching → spun yarn → drying → spooling → packaging.

CN 101054746B discloses a spinning process of flax short-ramie high count yarn, which comprises the following steps: the method comprises the steps of machine short hemp raw material → humidification and curing → large cutting → circular comb → extension → drawing → roving → scouring and bleaching → spun yarn → drying → spooling → packaging.

CN 101892535A discloses a method for spinning medium and high count pure flax yarn by using flax secondary coarse staple as main raw material, and the medium and high count pure flax yarn is spun by processes of flax mixing and humidifying, combined carding, secondary pre-needling, three times of combing, four times of back needling, roving, boiling and bleaching, spinning, drying, spooling and the like.

CN 108796627A discloses a ramie boiling degumming process, which comprises dividing raw ramie into a strand by a beam splitter through mechanical opening treatment, then leaving the ramie through hackling treatment, humidifying the ramie through adding water or a surfactant, then removing static electricity, combing the humidified ramie, carding on a carding machine, carding the carded ramie, carrying out needle-carding treatment on the straightened limit, making two fibers into fiber strips, combing the two fibers into the fiber strips, making the four fibers into the fiber strips, making the limit strips into yarns, boiling and degumming the made yarns, and then carrying out boiling degumming treatment, cleaning agent washing, hot water washing, softening treatment, drying, health preserving treatment and spooling treatment and packaging treatment on the yarns.

The above patent shows the basic process of producing flax spun yarn by using flax short-fiber raw material, but has some problems, and the boiling and bleaching steps in the flax process are basically the route of 'roving-boiling and bleaching-spun yarn' such as 'bleaching before spinning'. That is, the conventional flax spinning process is to spin rough yarn, the rough yarn is boiled and bleached, and then spun yarn, and the boiling and bleaching process is performed on the flax rough yarn. However, the boiling and bleaching step is the key to the quality of the finished spun yarn, because after the flax raw material is spun into the roving, if the boiling and bleaching is too light in the boiling and bleaching process, the impurities are not completely removed, the nep amount is large, and the flax fibers are hidden in the roving, and if the boiling and bleaching degree is heavy, and the pectin amount of the flax fibers is seriously removed, the strength of the roving is directly affected, and the strength of the final spun yarn is reduced. And because the thickness of the fiber of the roving is not uniform, the roving becomes more non-uniform after boiling and bleaching, the strength of the boiled and bleached roving is greatly reduced, the strength is not uniform, the thick knot is thicker and thinner, and hydrogen bonds are formed between the fibers, so that the fibers are not easy to slide when spinning the spun yarn. This causes problems that the spun yarn is likely to be drawn insufficiently to form slub, or the tension is too large to cause breakage. Therefore, the spun yarn spun from the "problem" roving finally causes an irreversible unevenness in the spun yarn, and frequently breaks when the spun yarn is spun, which directly affects the hand feeling and strength of the final hemp fabric.

Moreover, when the roving is boiled and bleached, the problem of unsmooth circulation exists in the cauldron, and water circulation can cause impact to the roving under certain conditions, and insoluble substances such as part of washed fibers and impurities can cause interference in water, and these insoluble substances can not follow the water flow when the roving is boiled and bleached, can continue to adhere to the surface of roving. When spun yarns are spun by the impurities, the impurities form rough mud, so that the spun yarns are muddy and can be wound on the spun yarns to influence yarn evenness. In addition, the presence of the hemp-mud affects the dyeing, and the color of the place with the hemp-mud is darker than that of the place without the hemp-mud. The reason is that these hemp muds have a porosity greater than that of the fibers and tend to adsorb dyes. The traditional roving scouring and bleaching process usually needs 4-6 hours of treatment time, needs a large amount of water for acid washing and neutralization, and has the disadvantages of long process duration, large medicament and water consumption, high cost and limited production efficiency. The above problems become an urgent problem to be solved by those skilled in the art of flax spinning.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to solve the technical problem of providing the flax spun yarn spinning process based on the short flax raw material, which has the advantages of good yarn quality, effective improvement of the strength and the uniformity of the spun yarn, effective reduction of the yarn breakage rate, softer and looser yarn and great saving of the boiling and bleaching cost.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a flax spun yarn spinning process based on a short flax raw material takes long flax as a raw material and comprises the following steps:

(1) and (3) strip making: the short ramie produced by the hackling machine and/or the first coarse short fiber and the second coarse short fiber after impurity removal treatment are carded into ramie stripes by the hackling machine after pretreatment;

(2) drawing: carrying out needle combing on the obtained ramie stripes by a 3-4-channel short ramie drawing frame to further straighten, parallel and uniformly mix the fibrilia, and preparing into fiber stripes with certain fineness;

(3) roving: drafting and twisting the obtained fiber strips with certain fineness by a roving machine to prepare roving, and winding the roving to form package roving;

(4) pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 0.5-7, the temperature of the water bath is set to be 20-100 ℃, and the time of the water bath treatment is 15-45 minutes;

(5) spinning: drafting, twisting and winding the pre-bleached package roving by a spinning machine to finally form spun yarn cop;

(6) and final bleaching: the spun yarn bobbin is sleeved on a creel and is put into a boiling and bleaching pot, and the steps are carried out in the following sequence:

a. acid washing, namely adding water into a boiling and bleaching pot, primarily heating, injecting oxalic acid and sulfuric acid which are uniformly stirred and have mass concentrations of 2.32g/L and 4.35g/L respectively into the boiling and bleaching pot after heating for 5 minutes, heating to 40 ℃, preserving heat for 20 minutes, and discharging liquid;

b. neutralizing, namely uniformly stirring soda ash with the mass concentration of 5.80g/L, injecting into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 10 minutes, and discharging liquid;

c. primarily bleaching, preparing primary bleaching liquid, injecting water into a container, heating to 30-35 ℃, respectively adding pectinase with the mass concentration of 2.90g/L and a penetrant, stirring uniformly to form primary bleaching liquid, then injecting the primary bleaching liquid into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 40 minutes, and discharging liquid;

d. re-bleaching, namely preparing a re-bleaching solution, injecting water into a container, heating to 30-35 ℃, respectively adding soda ash with the mass concentration of 3-5 g/L, sodium hydroxide with the mass concentration of 2-4 g/L, a refining agent with the mass concentration of 3-5 g/L and hydrogen peroxide with the mass concentration of 11-12 g/L, stirring uniformly to form a re-bleaching solution, then injecting the re-bleaching solution into a boiling and bleaching pot, heating to 95 ℃, preserving heat for 40 minutes, and discharging liquid;

e. and (4) washing, namely washing the re-bleached flax spun yarn.

According to the flax spun yarn spinning process based on the short flax raw material, the penetrant with the mass concentration of 2g/L is added in the acid washing process in the step (6), and the penetrant is sodium secondary alkyl sulfonate.

In the flax spun yarn spinning process based on the short flax raw material, the penetrant is sodium secondary alkyl sulfonate.

In the step (6), the linen spun yarn after re-bleaching is subjected to secondary re-bleaching, secondary re-bleaching liquid is prepared, water is injected into a container, the temperature is raised to 30-35 ℃, soda with the mass concentration of 2.90g/L and hydrogen peroxide with the mass concentration of 8.70g/L are respectively added, the mixture is stirred and uniformly mixed to form secondary re-bleaching liquid, then the secondary re-bleaching liquid is injected into a boiling and bleaching pot, the temperature is raised to 90 ℃, and after the temperature is kept for 40 minutes, liquid is discharged.

In the step (6) and the step (e), during washing, water is injected into the boiling and bleaching pot, sodium sulfite with the mass concentration of 1.50g/L is added, the temperature is raised to 80 ℃ and kept for 10 minutes, then the boiling and bleaching pot is naturally cooled to the room temperature, acetic acid with the mass concentration of 0.72g/L is added, the temperature is raised to 60 ℃ and kept for 10 minutes, then the boiling and bleaching pot is naturally cooled to the room temperature, finally the yarn lubricant with the mass concentration of 5g/L is added, the temperature is raised to 40 ℃ and kept for 20 minutes.

According to the spun flax yarn spinning process based on the short flax raw material, the pectin removal amount of the spun flax yarn is 80-90% of the pectin content of the original flax fiber.

In the spinning process of the spun flax yarn based on the short flax raw material, the water bath solution for treating the spun flax yarn in the water bath in the step (4) is water or an aqueous solution containing an acid medicament.

In the flax spun yarn spinning process based on the short flax raw material, the aqueous solution containing the acidic medicament is a sulfuric acid aqueous solution or an acetic acid aqueous solution.

According to the flax spun yarn spinning process based on the short flax raw materials, the refining agent is a compound of a negative non-ionic surfactant, and the yarn lubricant is an alkyl quaternary ammonium salt compound.

The flax spun yarn spinning process based on the short flax raw material further comprises the step (7), the flax yarn after the final bleaching treatment is subjected to dehydration and drying treatment, the drying temperature is 90-100 ℃, and the moisture regain of the dried flax yarn is 4-7%.

The flax spun yarn spinning process based on the short flax raw material has the advantages that: the invention adopts the new concept of 'spinning before bleaching', namely the process of boiling and bleaching spun yarn, and breaks through the method of boiling and bleaching the roving by the traditional fibrilia 'spinning after bleaching'. The method has the advantages that the rough yarn is prebleached, pectin can be softened and swelled after the rough yarn is soaked in water, cohesive force between short ramie in the rough yarn is increased, the method is more favorable for a drafting process during spinning of the spun yarn, and strength and uniformity of the spun yarn can be improved. And finally bleaching the spun yarn, wherein the spun yarn is twisted to form a yarn, the roving is not boiled and bleached, and pectin is not damaged, so that the spun yarn is ensured to have certain strength after being spun into the spun yarn, and the fiber length of a bundle in the roving is not damaged, so that the spun yarn is ensured to be more uniform and ensured to have high strength after being finally bleached, the yarn forming quality is high, the end breakage rate is greatly reduced, and the obtained flax spun yarn is more fluffy among fibers, has gaps, and is softer in hand feeling. The invention divides the difficult problems in the traditional boiling and bleaching and spinning process into rough yarn pre-bleaching and spun yarn final bleaching, and divides the difficult problem that the boiling and bleaching degree of the traditional rough yarn is difficult to control into two steps, thereby realizing the controllability of the process and ensuring the higher yarn quality of the flax spun yarn.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is an electron microscope photograph of the spun yarn without scouring and bleaching;

FIG. 3 is an electron microscope photograph of the appearance of flax spun yarn obtained by the traditional "float-first and spin-last" process;

FIG. 4 is a cross-sectional electron micrograph of a flax spun yarn obtained by a traditional "float-first-spin" process;

FIG. 5 is an electron microscope photograph of the flax spun yarn of the present invention;

fig. 6 is an electron micrograph of a cross section of the flax spun yarn of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples;

example 1:

as shown in fig. 1, a flax spun yarn spinning process based on a short flax raw material comprises the following steps:

(4) pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 0.5, the temperature of the water bath is set to be 20 ℃, and the time of the water bath treatment is 45 minutes; the water bath solution for treating the flax roving in the water bath is an aqueous solution containing an acid medicament. The aqueous solution containing the acidic agent is an aqueous solution of sulfuric acid. The method has the advantages that the rough yarn is pre-soaked in an acid environment, pectin on the surface of the fiber can be rapidly expanded and softened, and the cohesive force among fibers forming the flax rough yarn is enhanced, so that the strength of the flax rough yarn can be improved, the end breakage rate of the spun yarn can be reduced during spinning of the spun yarn, and the strength of the spun yarn is improved. And because pectin expands and softens, the pectin can be dissolved more easily when the spun yarn is boiled and bleached, and the boiling and bleaching efficiency is improved.

(5) Spinning: spinning: drafting, twisting and winding the pre-bleached package roving by a spinning machine to finally form spun yarn cop; in the step, the yarn forming comprises the working procedures of stretching, drawing, roving, spinning and the like. The method comprises the steps of processing a blended and fixed-weight long fiber hemp leaf into a hemp belt with a certain length through needle combing and mixing of two spreading machines, preparing continuous hemp strips through needle combing and drafting of a strip making machine, then combining 8-10 hemp strips, further straightening fibers, uniformly mixing the fibers through the needle combing effect of 3-4 strip making machines, preparing the hemp strips with a certain fineness, then spinning the hemp strips into rough yarns through 1-2 roving frames, and spinning the rough yarns into spun yarns through spinning machines.

(6) And final bleaching: sleeving the spun yarn bobbin on a creel, filling the spun yarn bobbin into a boiling and bleaching pot, and performing the steps in the following sequence:

a. acid washing, namely adding water into a boiling and bleaching pot, primarily heating, injecting oxalic acid and sulfuric acid which are uniformly stirred and have mass concentrations of 2.32g/L and 4.35g/L respectively into the boiling and bleaching pot after heating for 5 minutes, heating to 40 ℃, preserving heat for 20 minutes, and discharging liquid; in the embodiment, 2g/L of penetrant is added into the boiling and bleaching pot, and the penetrant is sodium secondary alkyl sulfonate.

c. primarily bleaching, preparing primary bleaching liquid, injecting water into a container, heating to 35 ℃, respectively adding pectinase with the mass concentration of 2.90g/L and a penetrant, stirring uniformly to form primary bleaching liquid, then injecting the primary bleaching liquid into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 40 minutes, and discharging liquid; the penetrant is secondary alkyl sodium sulfonate.

d. Re-bleaching, namely preparing re-bleaching liquid, injecting water into a container, heating to 30 ℃, respectively adding soda ash with the mass concentration of 5g/L, sodium hydroxide with the mass concentration of 4g/L, a refining agent with the mass concentration of 5g/L and hydrogen peroxide with the mass concentration of 12g/L, stirring uniformly to form re-bleaching liquid, then injecting the re-bleaching liquid into a boiling and bleaching pot, heating to 95 ℃, preserving heat for 40 minutes, and discharging liquid; the refining agent is a compound of anionic and nonionic surfactants.

In order to ensure that the cross section of the spun yarn has more voids and better fiber integrity, most of the non-cellulosic material between the fibers is removed, so that voids are generated between the fibers and the yarn is softer. In the step (6) of this embodiment, the linen spun yarn after being rebleached is rebleached for the second time, a secondary rebaching liquid is prepared, a container is additionally provided with water, the temperature is raised to 30 ℃, soda ash with the mass concentration of 2.90g/L and hydrogen peroxide with the mass concentration of 8.70g/L are respectively added, the mixture is stirred and evenly mixed to form the secondary rebaching liquid, then the secondary rebaching liquid is injected into a scouring and bleaching pot, the temperature is raised to 90 ℃, and after the temperature is kept for 40 minutes, the liquid is discharged. The secondary rebachining step is arranged to control the pectin removal amount among the flax spun yarn fibers, and because the pectin removal amount of the primary rebachining step is not easy to control, the traditional degumming is divided into two steps, the primary rebachining is equivalent to rough processing, the secondary rebachining can detect the pectin removal amount of the flax spun yarns according to the primary rebachining, then the secondary rebachining is performed according to the required pectin retention requirements and indexes such as yarn strength, and the like, the pectin removal amount can be controlled more easily and accurately in the step, compared with the traditional pectin removal amount which cannot be controlled accurately, the step has the effect of improving the yarn quality of the finished yarns, and in the embodiment, the pectin removal amount is 80% of the pectin content of the original flax fibers.

e. And (4) washing, namely washing the re-bleached flax spun yarn. When washing, injecting water into a boiling and bleaching pot, adding sodium sulfite with the mass concentration of 1.50g/L, heating to 80 ℃, keeping for 10 minutes, then naturally cooling to room temperature, adding acetic acid with the mass concentration of 0.72g/L, heating to 60 ℃, keeping for 10 minutes, then naturally cooling to room temperature, finally adding yarn lubricant with the mass concentration of 5g/L, heating to 40 ℃, and keeping for 20 minutes. The selected yarn lubricant is alkyl quaternary ammonium salt compound.

In order to ensure that the flax after wet spinning reaches the national specified moisture regain of less than 12 percent, the flax is convenient to transport, sell and use in the next procedure and store in a human warehouse. The method carries out dehydration and drying treatment on the washed flax spun yarn, wherein the drying temperature is 90 ℃, and the moisture regain of the dried flax spun yarn is 7%. Of course, drying with steam, which is currently common, is also possible.

Example 2:

the same parts of this embodiment as those of embodiment 1 are not described again, but the differences are as follows: step (4), pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 3.5, the temperature of the water bath is set to be 60 ℃, and the time of the water bath treatment is 30 minutes; the water bath solution for treating the flax roving in the water bath is water or an aqueous solution containing an acid medicament. The aqueous solution containing the acidic medicament is an acetic acid aqueous solution.

c. Primarily bleaching, preparing primary bleaching liquid, injecting water into a container, heating to 33 ℃, respectively adding pectinase with the mass concentration of 2.90g/L and a penetrant, stirring uniformly to form primary bleaching liquid, then injecting the primary bleaching liquid into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 40 minutes, and discharging liquid; the penetrant is secondary alkyl sodium sulfonate.

d. Re-bleaching, namely preparing re-bleaching liquid, injecting water into a container, heating to 33 ℃, respectively adding soda ash with the mass concentration of 4g/L, 2.90g/L sodium hydroxide, 4g/L refining agent and 11.60g/L hydrogen peroxide, stirring uniformly to form re-bleaching liquid, then injecting the re-bleaching liquid into a boiling and bleaching pot, heating to 95 ℃, preserving heat for 40 minutes, and discharging liquid;

in the step (6), carrying out secondary rebachining on the re-bleached flax spun yarn, blending a secondary rebachining solution, injecting water into a container, heating to 32 ℃, respectively adding soda ash with the mass concentration of 2.90g/L and hydrogen peroxide with the mass concentration of 8.70g/L, stirring uniformly to form a secondary rebachining solution, then injecting the secondary rebachining solution into a boiling and bleaching pot, heating to 90 ℃, preserving heat for 40 minutes, and discharging liquid. The pectin removal amount is 83% of the pectin content of the original flax fiber.

e. And (4) washing, namely washing the re-bleached flax spun yarn.

In order to ensure that the flax after wet spinning reaches the national specified moisture regain of less than 12 percent, the flax is convenient to transport, sell and use in the next procedure and store in a human warehouse. The invention carries out dehydration and drying treatment on the washed flax spun yarn, the drying temperature is 94 ℃, and the moisture regain of the dried flax yarn is 6.5%. Of course, drying with steam, which is currently common, is also possible.

Example 3:

the same parts of this embodiment as those of embodiments 1 and 2 are not described again, but the differences are as follows: step (4), pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 7, the temperature of the water bath is set to be 100 ℃, and the time of the water bath treatment is 15 minutes; the water bath solution for treating the flax roving is water. In this embodiment, the roving is pre-soaked in a neutral environment, and compared with an acidic environment, pectin on the surface of the fiber can be rapidly expanded and softened, and the cohesive force between fibers constituting the linen roving is enhanced, so that the strength of the linen roving can be improved, the end breakage rate of the spun yarn can be reduced when the spun yarn is spun, and the strength of the spun yarn can be improved. And because pectin expands and softens, the pectin can be dissolved more easily when the spun yarn is boiled and bleached, and the boiling and bleaching efficiency is improved.

(7) And final bleaching: sleeving the spun yarn bobbin on a creel, filling the spun yarn bobbin into a boiling and bleaching pot, and performing the steps in the following sequence:

c. primarily bleaching, preparing primary bleaching liquid, injecting water into a container, heating to 32 ℃, respectively adding pectinase with the mass concentration of 2.90g/L and a penetrant, stirring uniformly to form primary bleaching liquid, then injecting the primary bleaching liquid into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 40 minutes, and discharging liquid; the penetrant is secondary alkyl sodium sulfonate.

d. Re-bleaching, preparing a re-bleaching solution, injecting water into a container, heating to 32 ℃, respectively adding sodium carbonate with the mass concentration of 4.5g/L, sodium hydroxide with the mass concentration of 3.5g/L, a refining agent with the mass concentration of 3.5g/L and hydrogen peroxide with the mass concentration of 11.80g/L, stirring uniformly to form the re-bleaching solution, then injecting the re-bleaching solution into a boiling and bleaching pot, heating to 95 ℃, preserving heat for 40 minutes, and discharging liquid;

in the step (6), carrying out secondary rebachining on the re-bleached flax spun yarn, blending a secondary rebachining solution, injecting water into a container, heating to 34 ℃, respectively adding soda ash with the mass concentration of 2.90g/L and hydrogen peroxide with the mass concentration of 8.70g/L, stirring uniformly to form a secondary rebachining solution, then injecting the secondary rebachining solution into a boiling and bleaching pot, heating to 90 ℃, preserving heat for 40 minutes, and discharging liquid. The pectin removal amount is 86% of pectin content of the original flax fiber.

e. And (4) washing, namely washing the re-bleached flax spun yarn.

In order to ensure that the flax after wet spinning reaches the national specified moisture regain of less than 12 percent, the flax is convenient to transport, sell and use in the next procedure and store in a human warehouse. The invention carries out dehydration and drying treatment on the washed flax spun yarn, the drying temperature is 97 ℃, and the moisture regain of the dried flax spun yarn is 5%. Of course, drying with steam, which is currently common, is also possible.

Example 4:

the same parts of this embodiment as those of embodiments 1, 2 and 3 are not described again, but the differences are as follows: step (4), pre-bleaching: performing water bath treatment on the wound roving, wherein the pH range of the water bath is 5, the temperature of the water bath is set to be 75 ℃, and the time of the water bath treatment is 25 minutes; the water bath solution for treating the flax roving in the water bath contains an aqueous solution of an acid medicament. The aqueous solution containing the acidic agent is an aqueous solution of sulfuric acid.

c. primarily bleaching, preparing primary bleaching liquid, injecting water into a container, heating to 30 ℃, respectively adding pectinase with the mass concentration of 2.90g/L and a penetrant, stirring uniformly to form primary bleaching liquid, then injecting the primary bleaching liquid into a boiling and bleaching pot, heating to 60 ℃, preserving heat for 40 minutes, and discharging liquid; the penetrant is secondary alkyl sodium sulfonate.

d. Re-bleaching, namely preparing re-bleaching liquid, injecting water into a container, heating to 35 ℃, respectively adding 3/L of soda ash, 2g/L of sodium hydroxide, 3g/L of refining agent and 11g/L of hydrogen peroxide, stirring uniformly to form re-bleaching liquid, then injecting the re-bleaching liquid into a boiling and bleaching pot, heating to 95 ℃, preserving heat for 40 minutes, and discharging liquid;

in the step (6), carrying out secondary rebachining on the re-bleached flax spun yarn, blending a secondary rebachining solution, injecting water into a container, heating to 35 ℃, respectively adding 2.90g/L of soda ash and 8.70g/L of hydrogen peroxide, stirring uniformly to form a secondary rebachining solution, then injecting the secondary rebachining solution into a boiling and bleaching pot, heating to 90 ℃, preserving heat for 40 minutes, and discharging liquid. The pectin removal amount is 90% of the pectin content of the original flax fiber.

e. And (4) washing, namely washing the re-bleached flax spun yarn.

In order to ensure that the flax after wet spinning reaches the national specified moisture regain of less than 12 percent, the flax is convenient to transport, sell and use in the next procedure and store in a human warehouse. The invention carries out dehydration and drying treatment on the washed flax spun yarn, the drying temperature is 100 ℃, and the moisture regain of the dried flax spun yarn is 4%. Of course, drying with steam, which is currently common, is also possible.

The boiling and bleaching process of the invention is as follows:

in the traditional process, when the roving is used for spinning the spun yarn, the roving is soaked in boiled water for 1 minute, then the spun yarn is normally spun on a spinning frame, and the yarn breakage rate is observed in the process. In the spinning process of spinning before bleaching, the number of spun yarns is 32, and the number of spun yarns reaches 36 after boiling bleaching.

The traditional flax spinning process comprises the following steps: flax roving, boiling and bleaching, spinning (36 yarns), drying and spooling.

The flax spinning process of spinning first and then bleaching comprises the following steps: the method comprises the steps of roving flax, spinning (32), loose winding, boiling and bleaching (36), drying and winding.

Test process flow

Spinning process parameters

Yarn count	Draft multiple	Spindle speed (r/min)	Twist (/10cm)	Nylon hook (mg)
					36 pieces of	14.4	5600	572	130
32 pieces of	12.8	5600	530	130

Roving process parameters

Yarn count	Number of roving	Draft multiple	Twist (/10cm)	Ingot speed r/min	Thickness mm of each layer of yarn
						36 pieces of	2.5	10.7	36	550	550
32 pieces of	2.5	10.7	36	550	550

Drawing process technological parameters

Yarn count	0 and	00 and	1 and	2 and	3 and	powder and
							draft multiple	7.45-7.75	8.257	9.638	9.941	9.941	9.41-9.75
Number of combined root	6 and 1	6 and 1	8 and 1	8 and 1	8 and 1	4 and 1
							Fixed length (m)	1000	1000	1150	1400	1350	2000
Linear velocity (m/min)	18.3-19.7	18.4-19.8	20.8-22.1	21.6-22.1	21.6-22.5	22-23.2
							Weight (g/m)	22.07±0.3	16.36±0.3	13.86±0.3	11.38±0.2	9.34±0.2	4.0±1.5％

The results and analysis of the boiling and bleaching process of spinning before bleaching are as follows:

(1) aspect of fiber morphology

As can be seen from FIG. 2, the spun yarn fiber which is not boiled and bleached has better integrity, more impurities and more obvious bonding phenomenon among the fibers. As can be seen from FIGS. 3 and 4, the cheese fiber boiled and bleached by the enzyme oxygen bleaching process has more and more obvious cracks, the integrity of the fiber is damaged, the separation degree between the fibers is larger, and the caking property is lower. The fiber surface of the cheese spun by adopting the traditional spinning process (i.e. boiling before spinning) has more impurities and is not smooth; and the surface of the cheese fiber spun by the process of spinning first and bleaching second has less impurities and is smooth. As can be seen from fig. 5 and 6, the cross section of the yarn spun by the spinning-before-bleaching spinning process has more gaps, and the integrity of the fiber is better. And the yarn spun by the traditional spinning process has no gaps among fibers and has poor fiber integrity. The reason is that the spinning and bleaching process is to spin spun yarn first and then boil and bleach the loose bobbin, and the spun yarn is boiled and bleached to remove non-cellulose substances among fibers, so that gaps are generated among the fibers, and the yarn is softer. In the traditional spinning process, rough yarn is boiled and bleached, and spun yarn is spun, so that non-cellulose substances between fibers are removed in the rough yarn boiling and bleaching stage, the fibers are tightly adjacent to the fibers in the process of spinning the spun yarn, no gap exists, and the spun yarn is hard.

(2) Aspect of broken end rate and spinnability of spun yarn

In the traditional spinning process, the rough yarn is spun into spun yarn after being boiled and bleached, the boiled and bleached rough yarn can remove dust, impurities, pigments and lignin in the flax rough yarn, and the removal of the substances is beneficial to the subsequent spinning and dyeing and finishing. Scouring and bleaching the roving can also remove pectin in the roving, but the pectin is a binder for ensuring that single fibers of the flax can form cellulose fibers, and provides guarantee for the strength of the flax roving. After the rough yarn after scouring and bleaching loses most of pectin and lignin, the bonding force between fibers is reduced, so that the strength is reduced; and the chemical agents such as acid, alkali, oxygen, enzyme and the like adopted by the boiling and bleaching rough yarn and the higher boiling and bleaching temperature can damage the structure of the flax single fiber, so that the strength of the flax single fiber is reduced. Due to the factors, the splitting degree of the boiled and bleached flax roving is improved, the fiber length of the bundle is shortened, the strength is reduced, and the spinning of the flax roving and spun yarn is not facilitated. When spinning the spun yarn, the spinning machine runs at a high speed, the tension of a drafting area and an air ring is large, the strength of the boiled and bleached rough yarn is reduced, the requirement of spinning the spun yarn cannot be met, the broken ends are more during spinning the spun yarn, workers can not respond that the broken ends are not connected, and the production efficiency is low. However, the fiber bundle and the single fiber structure of the thick yarn without boiling and bleaching are not damaged by chemical treatment, so that the strength of the flax thick yarn is well ensured, the strength requirement in spinning the spun yarn can be met, the end breakage rate of the spun yarn is reduced by 86.7%, the spinnability is greatly improved, and the one-time doffing time is shortened by 9%. The non-cellulosic material on the non-chemically treated roving is not chemically altered nor thrown out by high speed centrifugal force, which reduces the amount of fluff near the spun yarn and at the separator plate when spinning the spun yarn. The spinning frame is convenient for the worker to clean the spinning frame, and water is saved.

Broken end rate and spinnability of spun yarn

Serial number	Percentage of broken ends (/ h)	Spinnability	Sesame mud (/ h)	Time to fall sand (h)
					1	15	Difference (D)	Multiple purpose	8.5
2	11	Difference (D)	Much more	8.5
					3	2	Superior food	Chinese character shao (a Chinese character of 'shao')	8
4	2	Superior food	Chinese character shao (a Chinese character of 'shao')	8

(3) Strength aspect of cone yarn

The breaking strength, breaking strength and minimum strength of the cone yarn spun by the traditional spinning process (No. 1 and No. 2) are all smaller than those of the cone yarn spun by the first spinning and then bleaching process (No. 3) by adopting enzyme oxygen bleaching; the strong CV value is that the cone yarn spun by the traditional spinning process is larger than the cone yarn spun by the prior spinning and bleaching process. The cone yarn spun by the spinning-first and then bleaching spinning process can reach the standard of the first-class product. The structure of the roving bundle fiber and the single fiber after boiling and bleaching is damaged, so that the spinning end breakage rate is increased, the slippage between the fiber and the fiber is easy due to the reduction of pectin, the number of the fiber in the unit section of the yarn is reduced through the drafting of a spinning machine, and the strength is reduced. The thick yarn which is not boiled and bleached keeps the original strength when spinning the spun yarn and becomes wet after being soaked by boiled water and warm water in water , and the wet strength of the flax is greater than the dry strength, thereby providing guarantee for overcoming the tension when spinning the spun yarn. The non-cellulose substances in the flax can be removed by boiling and bleaching after loose spooling, the fibers are not damaged by physical force, the non-cellulose substances which are not removed can be remained on the yarns after drying, the adhesive force is provided for the fibers in the yarns, and the strength of the yarns is further improved.

(4) Yarn evenness of cheese

No matter the yarn boiling process adopts enzyme oxygen bleaching or double oxygen bleaching, the yarn levelness CV value, the detail of-50%, the knot plus 200% and the knot plus 400% of the cheese spun by the traditional spinning process (No. 1 and No. 2) are all larger than those spun by the prior spinning and then bleaching process (No. 3). This is because the roving is boiled and bleached to remove a part of the material, so that the roving becomes uneven in thickness; and the spun yarn is spun with too much hemp mud, and the hemp mud mixed with short fibers is easily wound into the spun yarn to form slubby. The thick yarn which is not boiled and bleached has uniform thickness when spinning the spun yarn, and the spun yarn has good slivers due to less hemp mud; the loose bobbin is boiled and bleached to remove the non-cellulose components on the yarn, and the yarn has twist, so that the non-cellulose components can be uniformly removed, and the yarn has better evenness.

Strength of cone yarn

High class standard	≥667	≤19	≥24			≥380
							First class standard	≥612	≤20	≥22			≥350
Qualification standard	≥556	≤22	≥20			≥320
							Serial number	Breaking strength (cN)	Strong CV (%)	Breaking Strength (cN/tex)	Elongation (%)	Maximum strength (cN)	Minimum strength (cN)
1	578.8	24.26	20.8	1.6	721.8	365.2
							2	607	17.96	21.9	1.7	778	430
3	618.9	19.03	22.3	1.8	860.8	390
							4	654.2	18.53	23.5	2.1	813.2	479.2

Cheese yarn strip

Therefore, the test data show that the spinning and bleaching process has low end breakage rate, less hemp mud, good spinnability and short one-drop time when spinning spun yarns; the spun cheese has high strength, good evenness, smooth surface and good quality. The obtained spinning-before-bleaching process is obviously superior to the traditional spinning process. The yarn spun by the traditional spinning process has a compact structure and is thick and hard. Gaps exist among fibers of the yarn with the new structure spun by the process of spinning and bleaching, and the yarn is softer.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art should understand that they can make various changes, modifications, additions and substitutions within the spirit and scope of the present invention.

Claims

1. A flax spun yarn spinning process based on a short flax raw material takes long flax as a raw material, and is characterized by comprising the following steps:

e. and (4) washing, namely washing the re-bleached flax spun yarn.

2. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: and (3) adding a penetrant with the mass concentration of 2g/L in the acid washing process of the step (6), wherein the penetrant is secondary alkyl sodium sulfonate.

3. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: and c, in the initial bleaching step, the penetrant is secondary alkyl sodium sulfonate.

4. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: in the step (6), carrying out secondary rebachining on the rebleached flax spun yarn, blending a secondary rebachining solution, injecting water into a container, heating to 30-35 ℃, respectively adding soda ash with the mass concentration of 2.90g/L and hydrogen peroxide with the mass concentration of 8.70g/L, stirring and uniformly mixing to form a secondary rebachining solution, then injecting the secondary rebachining solution into a scouring and bleaching pot, heating to 90 ℃, preserving heat for 40 minutes, and discharging liquid.

5. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: in the step (6) and the step (e), during washing, water is injected into the boiling and bleaching pot, sodium sulfite with the mass concentration of 1.50g/L is added, the temperature is increased to 80 ℃ and kept for 10 minutes, then the boiling and bleaching pot is naturally cooled to the room temperature, acetic acid with the mass concentration of 0.72g/L is added, the temperature is increased to 60 ℃ and kept for 10 minutes, then the boiling and bleaching pot is naturally cooled to the room temperature, finally yarn lubricant with the mass concentration of 5g/L is added, the temperature is increased to 40 ℃ and kept for 20 minutes.

6. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: the pectin removal amount of the flax spun yarn is 80-90% of the pectin content of the original flax fiber.

7. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 1, wherein the spun flax yarn spinning process comprises the following steps: and (4) the water bath solution for treating the flax roving in the water bath in the step (4) is water or an aqueous solution containing an acid medicament.

8. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 7, wherein the spun flax yarn spinning process comprises the following steps: the aqueous solution containing the acidic medicament is a sulfuric acid aqueous solution or an acetic acid aqueous solution.

9. The spun flax yarn spinning process based on a ramie raw material as claimed in claim 5, wherein the spun flax yarn spinning process comprises the following steps: the refining agent is a complex of a negative nonionic surfactant, and the yarn lubricant is an alkyl quaternary ammonium salt complex.

10. The spun flax yarn spinning process based on a ramie raw material according to claim 9, further comprising a step (7) of dehydrating and drying the linen yarn after the final bleaching process, wherein the drying temperature is 90-100 ℃, and the moisture regain of the linen yarn after drying is 4% -7%.