阅读说明：本技术 一种莱赛尔竹纤维生产制造方法 (Method for producing Lyocell bamboo fiber ) 是由 王培荣 于 2021-06-17 设计创作，主要内容包括：一种莱赛尔竹纤维生产制造方法,属于莱赛尔纤维的生产技术领域。含有粉碎(粗粉碎、细粉碎)步骤、加NMMO混合制成浆粥步骤、溶解制成胶液步骤、卸料泵输送纺丝机步骤、水洗、切断、上油及烘干步骤；竹纤维制成的产品可在土壤中自然降解,分解后对环境无任何污染,是一种天然的、绿色的、环保型的纺织原料。同时竹纤维具有良好的透气性、瞬间吸水性、较强的耐磨性和良好的染色性等特性,具有天然抗菌、抑菌、除螨、防臭和抗紫外线功能,开发一种用竹材为原料的莱赛尔纤维制造方法,可以开拓莱赛尔纤维的原料范围,填补行业空白,具有重大意义。(The invention discloses a production and manufacturing method of Lyocell bamboo fibers, and belongs to the technical field of production of Lyocell fibers. The production and manufacturing method comprises the following steps: crushing (coarse crushing and fine crushing), adding NMMO (N-methylmorpholine-N-oxide) and mixing to prepare slurry, dissolving to prepare a glue solution, conveying to a spinning machine by a discharge pump, washing with water, cutting off, oiling and drying. A product prepared from the bamboo fibers can be naturally degraded in soil, and has no pollution to the environment after being decomposed, and is a natural, green and environment-friendly textile raw material. Meanwhile, the bamboo fibers have the characteristics of good air permeability, instant water absorption, relatively strong wear resistance, good dyeing property and the like, and have natural antibacterial, bacteriostatic, mite-removing, deodorant and anti-ultraviolet functions; the invention develops a manufacturing method of the Lyocell fibers by taking bamboo as a raw material, which can expand the raw material range of the Lyocell fibers, fills the industrial blank, and has great significance.)

1. A method for producing Lyocell bamboo fiber, Lyocell bamboo fiber is specification 1.33dtex 38mm, moisture regain 3.78%, dry breaking strength 4.05cN/dtex, wet breaking strength 3.41cN/dtex, 5% wet modulus 1.01cN/dtex, dry breaking elongation 11.5%, dry strength variation coefficient 7.9%, fineness deviation rate-3.0%, length deviation rate-2.0%, overlength rate 1.0%, double length fiber 12mg/100g, coarse doubling 29mg/100g, whiteness 72.1%, oil content 0.32%;

the method is characterized by comprising the following steps:

crushing (coarse crushing and fine crushing), adding NMMO (N-methyl-amino-methyl-N-methyl-ethyl-methyl-ethyl;

step 1, crushing:

after the bamboo pulp meeting the quality requirement is crushed twice, the bulk density of the bamboo pulp cellulose material is more than 80 g/L;

step 2, adding NMMO to mix and prepare slurry porridge: the pulverized powdery bamboo pulp and NMMO (methyl morpholine oxide) solvent are completely mixed in a pre-mixer and then enter a porridge tank to prepare uniform porridge;

propyl gallate is added into the NMMO solvent preparation, and the adding proportion is 1.5 per mill;

step 3, dissolving the pulp and porridge to prepare glue solution:

conveying the porridge in the porridge tank to a film evaporator by a single screw pump, wherein the temperature is 75-110 ℃, the vacuum degree is less than or equal to-97.5 kPa, and dissolving the porridge to prepare a glue solution; wherein: the frequency of the screw pump is 7.8Hz, and the retention time of the slurry congee in the film evaporator is about 15 min;

step 4, spinning:

the slurry congee is dehydrated at high temperature in a film evaporator, and is fully dissolved with NMMO to form a glue solution, and then the glue solution is conveyed to a spinning machine through a discharge pump (gear pump); a metering pump is arranged before entering the spinning machine; the requirement on temperature stability is very high in the conveying process, and constant temperature control is required; quantitatively feeding the glue solution to a spinning assembly through a metering pump, extruding the glue solution from a spinneret orifice, and then feeding the glue solution into a coagulating bath through a section of air gap; the air gap medium is air, and in the process, the glue solution trickle is drawn into a coagulating bath and forms a strand silk after passing through the coagulating bath;

step 5, washing, cutting, oiling and drying post-treatment:

the spinning post-treatment mainly comprises the steps of drawing, washing, cutting, refining and drying by a winding machine; the silk thread which is still in the partial swelling state after the spinning stretching is continuously stretched by multi-section water washing, then is cut off by a cutting machine, and is endowed with the smoothness, cohesion and antistatic property of the fiber by oiling; and (3) drying the curled wet fibers in a dryer after steam heat treatment to obtain the finished product of the lyocell bamboo fibers.

2. The method for producing lyocell bamboo fibers according to claim 1, wherein the mixing in step 2 is carried out at a N/C ratio of 7.0, a NMMO concentration of about 76%, a temperature of 80 ℃ in a porridge tank, and a stirring in the tank; propyl gallate is added into the NMMO solvent preparation according to the proportion of 1.5 per mill.

3. The method for producing lyocell bamboo fibers according to claim 1, wherein the parameters of the thin film evaporator of step 3 are:

frequency: 20 Hz;

current: 50A;

vacuum degree: less than or equal to 97.5 kPa;

temperature of the feeding section: 80 ℃;

the upper section temperature: 75 ℃;

middle section temperature: 74 ℃;

the temperature of the lower section: 87 ℃;

cone bottom temperature: 95 ℃;

outlet glue solution temperature: 104 ℃.

4. The method for producing lyocell bamboo fiber according to claim 1, wherein in the step 4 process, the main parameters are as follows:

discharge pump outlet pressure: 0.5 MPa;

frequency of the discharge pump: 20 Hz;

frequency of the metering pump: 30 Hz;

pressure of glue solution at an inlet of a metering pump: 3.3 MPa;

pressure of glue solution at an inlet of a metering pump: 2.5 MPa;

temperature of glue solution at outlet of metering pump: 104 ℃;

temperature of the coagulation bath: 18 ℃;

air gap air temperature: 10 ℃;

cooling wind speed: 5.0 m/s;

cooling air outlet humidity: 40 percent;

coagulation bath NMMO concentration: less than or equal to 30 percent;

spinning plate specification: 74400*0.095.

Technical Field

The invention relates to a method for producing lyocell bamboo fibers, belonging to the technical field of lyocell fiber production.

Background

Cellulose is a main component of plant cell walls, can be derived from trees, cotton, hemp and other plants, and is widely distributed, inexhaustible and inexhaustible in nature. Generally, most organic substances containing hydroxyl groups are readily soluble in water, such as alcohol, glucose, and the like, but cellulose is insoluble in water and most organic solvents. The molecular weight of cellulose is generally large, and is hundreds of low, and is tens of thousands of high, and intramolecular and intermolecular hydrogen bonds are easily formed, and the acting force covers the affinity action of a part of hydroxyl groups to water, so that the cellulose is insoluble in water or common organic solvents.

As petroleum resources are gradually reduced and influenced by factors such as the consciousness of advocating nature, health and environmental protection, people gradually turn to regenerated cellulose fibers. Lyocell fiber (Lyocell) is commonly called as "velveteen", is made from natural plant fiber as a raw material, is known in the middle of the 90 s of the 20 th century, and is known as the most valuable product in artificial fiber history in the last half century. The Lyocell fiber has various excellent performances of natural fiber and synthetic fiber, Lyocell is green fiber, raw materials of Lyocell are inexhaustible cellulose in nature, a production process has no chemical reaction, a used solvent is nontoxic, the recovery rate of the solvent can reach more than 99%, and the production process is green and environment-friendly, so the Lyocell fiber is called as '21 st century green fiber'.

The lyocell fiber production technology is a relatively mature solvent method regenerated cellulose fiber industrialized production technology at present, and domestic and foreign enterprises, colleges and scientific research institutions have more relevant researches, but relatively few lyocell fiber complete production technologies can be really mastered, and as a foreign enterprise which monopolizes the lyocell fiber production technology for a long time, the lyocell fiber production technology mastered a series of most advanced lyocell fiber relevant technologies such as lyocell fiber production equipment and production technology, breaks through the blockade of the production technology and equipment by the foreign enterprise, develops a mature and reliable lyocell fiber production technology and equipment, and can powerfully promote the development of the field of new fiber materials.

At present, the raw material for manufacturing the lyocell fiber is generally a wood raw material at home and abroad, and the lyocell fiber manufacturing method using bamboo as the raw material is developed, so that the raw material range of the lyocell fiber can be expanded, the blank of the industry is filled, and the method has great significance.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for producing and manufacturing lyocell bamboo fibers, develops a mature and reliable process for producing the lyocell bamboo fibers, reduces the production cost and the investment cost, widens the raw materials of the lyocell fibers, and further powerfully promotes the development of the field of new fiber materials in China.

A method for producing Lyocell bamboo fiber, Lyocell bamboo fiber is specification 1.33dtex 38mm, moisture regain 3.78%, dry breaking strength 4.05cN/dtex, wet breaking strength 3.41cN/dtex, 5% wet modulus 1.01cN/dtex, dry breaking elongation 11.5%, dry strength variation coefficient 7.9%, fineness deviation rate-3.0%, length deviation rate-2.0%, overlength rate 1.0%, double length fiber 12mg/100g, coarse doubling 29mg/100g, whiteness 72.1%, oil content 0.32%;

the method is characterized by comprising the following steps:

the method comprises the steps of crushing (coarse crushing and fine crushing), adding NMMO (N-methyl-ethyl-methyl-ethyl-methyl-ethyl.

Step 1, crushing:

after the bamboo pulp meeting the quality requirement is crushed twice, the bulk density of the bamboo pulp cellulose material is more than 80 g/L.

Step 2, adding NMMO to mix and prepare slurry porridge: the pulverized powdery bamboo pulp and NMMO (methyl morpholine oxide) solvent are completely mixed in a pre-mixer and then enter a porridge tank to prepare uniform porridge;

propyl gallate is added into the NMMO solvent preparation according to the proportion of 1.5 per mill.

Step 3, dissolving the pulp and porridge to prepare glue solution:

conveying the porridge in the porridge tank to a film evaporator by a single screw pump, wherein the temperature is 75-110 ℃, the vacuum degree is less than or equal to-97.5 kPa, and dissolving the porridge to prepare a glue solution; wherein: the frequency of the screw pump is 7.8Hz, and the retention time of the slurry in the film evaporator is about 15 min.

Step 4, spinning:

the slurry congee is dehydrated at high temperature in a film evaporator, and is fully dissolved with NMMO to form a glue solution, and then the glue solution is conveyed to a spinning machine through a discharge pump (gear pump); a metering pump is arranged before entering the spinning machine; the requirement on temperature stability is very high in the conveying process, and constant temperature control is required; quantitatively feeding the glue solution to a spinning assembly through a metering pump, extruding the glue solution from a spinneret orifice, and then feeding the glue solution into a coagulating bath through a section of air gap; the air gap medium is air, and in the process, the glue solution trickle is drawn into the coagulating bath and forms a strand after passing through the coagulating bath.

Step 5, washing, cutting, oiling and drying post-treatment:

the spinning post-treatment mainly comprises the steps of drawing, washing, cutting, refining and drying by a winding machine; the silk thread which is still in the partial swelling state after the spinning stretching is continuously stretched by multi-section water washing, then is cut off by a cutting machine, and is endowed with the smoothness, cohesion and antistatic property of the fiber by oiling; and (3) drying the curled wet fibers in a dryer after steam heat treatment to obtain the finished product of the lyocell bamboo fibers.

In the step 2, the N/C ratio is 7.0 when mixing, the concentration of NMMO is about 76%, the temperature is 80 ℃, the temperature in the porridge tank is kept at 80 ℃, and the stirring in the tank is kept; propyl gallate is added into the NMMO solvent preparation according to the proportion of 1.5 per mill.

The parameters of the thin film evaporator in the step 3 are as follows:

frequency: 20 Hz;

current: 50A;

vacuum degree: less than or equal to 97.5 kPa;

temperature of the feeding section: 80 ℃;

the upper section temperature: 75 ℃;

middle section temperature: 74 ℃;

the temperature of the lower section: 87 ℃;

cone bottom temperature: 95 ℃;

outlet glue solution temperature: 104 ℃.

In the process of step 4, the main parameters are as follows:

discharge pump outlet pressure: 0.5 MPa;

frequency of the discharge pump: 20 Hz;

frequency of the metering pump: 30 Hz;

pressure of glue solution at an inlet of a metering pump: 3.3 MPa;

pressure of glue solution at an inlet of a metering pump: 2.5 MPa;

temperature of glue solution at outlet of metering pump: 104 ℃;

temperature of the coagulation bath: 18 ℃;

air gap air temperature: 10 ℃;

cooling wind speed: 5.0 m/s;

cooling air outlet humidity: 40 percent;

coagulation bath NMMO concentration: less than or equal to 30 percent;

spinning plate specification: 74400*0.095.

The invention has the following beneficial effects:

at present, the raw materials for manufacturing the lyocell fibers at home and abroad are generally wood raw materials, most of the raw materials mainly comprise broad leaf pulp, and a small part of the raw materials comprise needle leaf pulp, so that bamboo resources in China are rich, the wide and the utilizable resources are high, the growth period of the bamboo is short, the bamboo can be grown into wood in 2-3 years, the bamboo can be planted for a long time, the bamboo can grow and update quickly, the resources such as cotton and wood can be replaced, and the bamboo can be used sustainably. The product made of the bamboo fiber can be naturally degraded in soil, has no pollution to the environment after being decomposed, and is a natural, green and environment-friendly textile raw material. Meanwhile, the bamboo fiber has the characteristics of good air permeability, instant water absorption, strong wear resistance, good dyeing property and the like, has the functions of natural antibiosis, bacteriostasis, mite removal, deodorization and ultraviolet resistance, develops a method for manufacturing the lyocell fiber by using bamboo as a raw material, can develop the raw material range of the lyocell fiber, fills the blank of the industry, and has great significance.

Detailed Description

It will be apparent that those skilled in the art can make many modifications and variations based on the spirit of the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element, component or section is referred to as being "connected" to another element, component or section, it can be directly connected to the other element or section or intervening elements or sections may also be present. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art.

The following examples are further illustrative in order to facilitate the understanding of the embodiments, and the present invention is not limited to the examples.

Example 1: a method for producing Lyocell bamboo fiber comprises the steps of using Sichuan bamboo pulp as a raw material, wherein the quantity of the Sichuan bamboo pulp is 40kg (absolute dryness), absolute dryness is a pure dry material without water, the absolute dryness is relative to air drying, the normal air drying material has about 10% of water, and the water is removed by 40kg of Sichuan bamboo pulp through calculation.

The quality indexes are as follows: DP512, alpha cellulose 94.8%, ash 0.18%, resin 0.14%, whiteness 85%, small dust 33mm²Per kg, 4.5% pentosan, 20mg/kg iron, 2mg/kg copper, 400mg/kg calcium, 60mg/kg magnesium.

Fiber is a substance distributed throughout the natural world, in plant fiber, cellulose is a substance that determines the properties of fiber, cellulose is a carbohydrate and also contains a plurality of sugar units, and its chemical formula is (C6H10O5) N, where N is the number of repeating sugar units or the Degree of Polymerization (DP), the number of N values varies depending on the various sources of cellulose and the processing conditions to which it is subjected, the properties of cellulose are related to the DP of the cellulose component, in general, long-chain cellulose is called alpha cellulose (methylcellulose), and a large number of short-chain polysaccharides are collectively called hemicellulose.

1. Type A cellulose:

alpha cellulose is called as 'alpha cellulose' for short, it is the main body of pulp, the pulp is treated with 17.5% NaOH solution at 20 deg.C for 15 minutes, the insoluble part is called as alpha cellulose, the polymerization degree is above 200, the 'alpha cellulose' is also called as alpha cellulose.

2. DP (degree of polymerization): the degree of polymerization refers to the number of "basic units" constituting a cellulose macromolecular chain, and generally refers to the average degree of polymerization in production, expressed as DP, which reflects the length of the cellulose molecular chain.

3. Ash content:

the ash content is residue of pulp burned in 750 deg.c muffle furnace, and is mainly silicon dioxide, calcium, magnesium, iron and other metal ions, and the pulp has over high ash content and iron content, so that the filtering performance of the glue solution is deteriorated seriously and the side effect is increased by times.

4. Dust degree:

the dust is any impurity which is embedded in the pulp and is obviously different from the color of the pulp and can be observed by reflected light or transmitted light, the dust degree refers to the number of spots containing non-fiber impurities on each square meter of the pulp, the pulp has high dust degree, and the glue solution is difficult to filter, wherein:

small dust: the area is more than or equal to 0.05mm²，≤3.0mm²The dust of (2);

large dust: dust with the area of more than or equal to 3.0mm 2.

5. Whiteness:

the index refers to the total reflection capacity of the pulp to seven monochromatic lights in the visible spectrum, and is internationally the ratio of the reflectivity measured by blue single light with the wavelength of 457nm to the reflectivity measured on the surface of pure magnesium oxide under the same condition, expressed in percent, wherein the higher the numerical value, the whiter the pulp is visually, the higher the whiteness of the pulp is, and the whiter the prepared fiber is.

The method comprises the following steps of crushing, adding NMMO (N-methyl-MO) into the mixture to prepare slurry, dissolving the slurry into glue, spinning, washing, cutting, oiling, drying and other post-treatment steps.

Wherein:

(1) a crushing step: manually tearing the sheet bamboo pulp into large sheets, and then crushing twice by a coarse crusher and a fine crusher, wherein the bulk density of the bamboo pulp cellulose material is more than 80 g/L.

(2) Adding NMMO and mixing to prepare slurry porridge: 368kg of NMMO solvent with the concentration of 76% (namely the N/C ratio is 7.0) is prepared, the N/C ratio is the ratio of NMMO to cellulose, propyl gallate is added in the preparation, and the adding proportion is 1.5 per mill. Heating to 80 deg.C, mixing the bamboo pulp powder and NMMO solvent in a pre-mixer, and making into uniform porridge in a porridge tank, wherein the temperature in the porridge tank is 80 deg.C, and stirring. The temperature of the solvent and the temperature in the tank are raised by 1# electric heating oil. 1# electric heating oil set temperature: at 83 deg.c.

(3) And the step of dissolving the paste into glue solution:

conveying the porridge in the porridge tank to a film evaporator by a single screw pump, and dissolving the porridge to obtain a glue solution at a temperature of 75-110 ℃ and a vacuum degree of less than or equal to-97.5 kPa. Wherein: the frequency of the screw pump is 7.8Hz, and the retention time of the slurry in the film evaporator is about 15 min.

The parameters of the thin film evaporator were:

frequency: 20 Hz;

current: 50A;

vacuum degree: less than or equal to 97.5 kPa;

temperature of the feeding section: 80 ℃;

the upper section temperature: 75 ℃;

middle section temperature: 74 ℃;

the temperature of the lower section: 87 ℃;

cone bottom temperature: 95 ℃;

outlet glue solution temperature: 104 ℃.

The temperature in the thin film evaporator is raised by using No. 2 and No. 4 electric heating oil, and the bottom is raised by using No. 3 electric heating oil.

Respective set temperatures of 2# and 4# electric heating oils: 105 ℃.

3# electric heating oil set temperature: and (2) at 108 ℃.

(4) And a spinning step:

the slurry is dehydrated at high temperature in a film evaporator, is fully dissolved with NMMO to form a glue solution, and then enters a spinning machine after being discharged and conveyed by a discharging pump (gear pump) and metered by a metering pump. And (4) extruding the mixture from a spinneret orifice, entering a coagulating bath through an air gap, and forming filament after the coagulation bath. In the process, the main parameters are as follows:

spinning speed: 25 m/min;

discharge pump outlet pressure: 0.5 MPa;

frequency of the discharge pump: 20 Hz;

frequency of the metering pump: 30 Hz;

pressure of glue solution at an inlet of a metering pump: 3.3 MPa;

pressure of glue solution at an inlet of a metering pump: 2.5 MPa;

temperature of glue solution at outlet of metering pump: 104 ℃;

temperature of the coagulation bath: 18 ℃;

air gap air temperature: 10 ℃;

cooling wind speed: 5.0 m/s;

cooling air outlet humidity: 40 percent;

coagulation bath NMMO concentration: less than or equal to 30 percent;

spinning plate specification: 74400 × 0.095;

the glue solution conveying pipeline is heated and insulated by 3# electric heating oil.

Setting the temperature of a water chiller: 15 ℃ is prepared.

(5) And the post-treatment steps of water washing, cutting, oiling, drying and the like are as follows:

and stretching by a winding machine, washing by a washing machine, cutting by a cutting machine, oiling by a refining machine, and drying by steam of a drying machine after spinning to obtain the lyocell bamboo fiber.

The indexes of the finished product of the lyocell bamboo fiber are as follows: specification 1.33dtex 38mm, moisture regain 5.4%, dry breaking strength 3.98cN/dtex, wet breaking strength 3.39cN/dtex, 5% wet modulus 1.01cN/dtex, dry breaking elongation 11.2%, dry strength variation coefficient 7.6%, fineness deviation rate-2.3%, length deviation rate-2.1%, super length rate 1.0%, double length fiber 10mg/100g, coarse drawn yarn 30.5mg/100g, whiteness 70.6%, oil content 0.34%.

Example 2: a method for producing Lyocell bamboo fiber comprises the following steps of taking Sichuan bamboo pulp as raw materials, wherein the quantity of the Sichuan bamboo pulp is 40kg (absolute dry), and the quality indexes are as follows: DP532, alpha cellulose 94.5%, ash 0.17%, resin 0.15%, whiteness 83%, dust 30mm²Per kg, 4.3% pentosan, 19mg/kg iron, 2mg/kg copper, 380mg/kg calcium, 55mg/kg magnesium; the absolute drying is pure dry materials without water, compared with air drying, the absolute drying is about 10% of moisture in the normally air-dried materials, and the moisture is removed by calculation.

A process for preparing the lyocell bamboo fibres includes such steps as pulverizing, mixing with NMMO to obtain gruel, dissolving the gruel to obtain colloidal liquid, spinning, water washing, cutting, applying oil, and baking. Wherein:

(1) a crushing step: manually tearing the sheet bamboo pulp into large sheets, and then crushing twice by a coarse crusher and a fine crusher, wherein the bulk density of the bamboo pulp cellulose material is more than 80 g/L.

(2) Adding NMMO and mixing to prepare slurry porridge: 368kg of NMMO solvent with the concentration of 76% (namely the N/C ratio is 7.0) is prepared, and propyl gallate is added in the preparation, wherein the adding proportion is 1.5 per mill. Heating to 80 deg.C, mixing the bamboo pulp powder and NMMO solvent in a pre-mixer, and making into uniform porridge in a porridge tank, wherein the temperature in the porridge tank is 80 deg.C, and stirring. The temperature of the solvent and the temperature in the tank are raised by 1# electric heating oil. 1# electric heating oil set temperature: at 83 deg.c.

(3) And the step of dissolving the paste into glue solution:

conveying the porridge in the porridge tank to a film evaporator by a single screw pump, and dissolving the porridge to obtain a glue solution at a temperature of 75-110 ℃ and a vacuum degree of less than or equal to-97.5 kPa. Wherein: the frequency of the screw pump is 7.8Hz, and the retention time of the slurry congee in the film evaporator is about 15 min;

the parameters of the thin film evaporator were:

frequency: 20 Hz;

current: 50A;

vacuum degree: less than or equal to 97.5 kPa;

temperature of the feeding section: 80 ℃;

the upper section temperature: 75 ℃;

middle section temperature: 74 ℃;

the temperature of the lower section: 87 ℃;

cone bottom temperature: 95 ℃;

outlet glue solution temperature: 104 ℃.

The temperature in the thin film evaporator is raised by using No. 2 and No. 4 electric heating oil, and the bottom is raised by using No. 3 electric heating oil.

Respective set temperatures of 2# and 4# electric heating oils: 105 ℃.

3# electric heating oil set temperature: and (2) at 108 ℃.

The meanings of the No. 1 electric heating oil, the No. 2 electric heating oil, the No. 3 electric heating oil and the No. 4 electric heating oil are as follows:

conventionally, the heating source for fiber production is low pressure steam. In this embodiment, because the glue solution needs to be evaporated and transported under the requirement of a certain temperature, no steam source is used for heating, 4 sets of electric heating devices are set up in an electric heating mode, and 1# electric heating oil, 2# electric heating oil, 3# electric heating oil and 4# electric heating oil are used respectively.

(4) And a spinning step:

the slurry is dehydrated at high temperature in a film evaporator, is fully dissolved with NMMO to form a glue solution, and then enters a spinning machine after being discharged and conveyed by a discharging pump (gear pump) and metered by a metering pump. And (4) extruding the mixture from a spinneret orifice, entering a coagulating bath through an air gap, and forming filament after the coagulation bath. In the process, the main parameters are as follows:

spinning speed: 25 m/min;

discharge pump outlet pressure: 0.5 MPa;

frequency of the discharge pump: 20 Hz;

frequency of the metering pump: 30 Hz;

pressure of glue solution at an inlet of a metering pump: 3.3 MPa;

pressure of glue solution at an inlet of a metering pump: 2.5 MPa;

temperature of glue solution at outlet of metering pump: 104 ℃;

temperature of the coagulation bath: 18 ℃;

air gap air temperature: 10 ℃;

cooling wind speed: 5.0 m/s;

cooling air outlet humidity: 40 percent;

coagulation bath NMMO concentration: less than or equal to 30 percent;

spinning plate specification: 74400 × 0.095;

the glue solution conveying pipeline is heated and insulated by 3# electric heating oil.

Setting the temperature of a water chiller: 15 ℃ is prepared.

(5) And the post-treatment steps of water washing, cutting, oiling, drying and the like are as follows:

and stretching by a winding machine, washing by a washing machine, cutting by a cutting machine, oiling by a refining machine, and drying by steam of a drying machine after spinning to obtain the lyocell bamboo fiber.

The indexes of the finished product of the lyocell bamboo fiber are as follows: specification 1.33dtex 38mm, moisture regain 3.78%, dry break strength 4.05cN/dtex, wet break strength 3.41cN/dtex, 5% wet modulus 1.01cN/dtex, dry break elongation 11.5%, dry strength variation coefficient 7.9%, fineness deviation rate-3.0%, length deviation rate-2.0%, super length rate 1.0%, double length fiber 12mg/100g, coarse drawn yarn 29mg/100g, whiteness 72.1%, oil content 0.32%.

Example 3: a method for producing Lyocell bamboo fiber comprises the following steps of taking Sichuan bamboo pulp as raw material, wherein the quantity of the Sichuan bamboo pulp is 40kg (absolute dry), and the quality indexes are as follows: DP565, alpha-cellulose 94.3%, ash 0.16%, resin 0.16%, whiteness 81%, small dust 32mm²Per kg, 4.1% pentosan, 18mg/kg iron, 2mg/kg copper, 280mg/kg calcium, 51mg/kg magnesium; the absolute drying is pure dry materials without water, compared with air drying, the absolute drying is about 10% of moisture in the normally air-dried materials, and the moisture is removed by calculation.

A process for preparing the lyocell bamboo fibres includes such steps as pulverizing, mixing with NMMO to obtain gruel, dissolving the gruel to obtain colloidal liquid, spinning, water washing, cutting, applying oil, and baking. Wherein:

(1) a crushing step: manually tearing the sheet bamboo pulp into large sheets, and then crushing twice by a coarse crusher and a fine crusher, wherein the bulk density of the bamboo pulp cellulose material is more than 80 g/L.

(2) Adding NMMO and mixing to prepare slurry porridge: 368kg of NMMO solvent with the concentration of 76% (namely the N/C ratio is 7.0) is prepared, and propyl gallate is added in the preparation, wherein the adding proportion is 1.5 per mill. Heating to 80 deg.C, mixing the bamboo pulp powder and NMMO solvent in a pre-mixer, and making into uniform porridge in a porridge tank, wherein the temperature in the porridge tank is 80 deg.C, and stirring. The temperature of the solvent and the temperature in the tank are raised by 1# electric heating oil. 1# electric heating oil set temperature: at 83 deg.c.

(3) And the step of dissolving the paste into glue solution:

conveying the porridge in the porridge tank to a film evaporator by a single screw pump, and dissolving the porridge to obtain a glue solution at a temperature of 75-110 ℃ and a vacuum degree of less than or equal to-97.5 kPa. Wherein: the frequency of the screw pump is 7.8Hz, and the retention time of the slurry in the film evaporator is about 15 min.

The parameters of the thin film evaporator were:

frequency: 20 Hz;

current: 50A;

vacuum degree: less than or equal to 97.5 kPa;

temperature of the feeding section: 80 ℃;

the upper section temperature: 75 ℃;

middle section temperature: 74 ℃;

the temperature of the lower section: 87 ℃;

cone bottom temperature: 95 ℃;

outlet glue solution temperature: 104 ℃;

the temperature in the thin film evaporator is raised by using No. 2 and No. 4 electric heating oil, and the bottom is raised by using No. 3 electric heating oil.

Respective set temperatures of 2# and 4# electric heating oils: 105 ℃.

3# electric heating oil set temperature: and (2) at 108 ℃.

The meanings of the No. 1 electric heating oil, the No. 2 electric heating oil, the No. 3 electric heating oil and the No. 4 electric heating oil are as follows:

conventionally, the heating source for fiber production is low pressure steam. In this embodiment, because the glue solution needs to be evaporated and transported under the requirement of a certain temperature, no steam source is used for heating, 4 sets of electric heating devices are set up in an electric heating mode, and 1# electric heating oil, 2# electric heating oil, 3# electric heating oil and 4# electric heating oil are used respectively.

(4) And a spinning step:

the slurry is dehydrated at high temperature in a film evaporator, is fully dissolved with NMMO to form a glue solution, and then enters a spinning machine after being discharged and conveyed by a discharging pump (gear pump) and metered by a metering pump. And (4) extruding the mixture from a spinneret orifice, entering a coagulating bath through an air gap, and forming filament after the coagulation bath. In the process, the main parameters are as follows:

spinning speed: 25 m/min;

discharge pump outlet pressure: 0.5 MPa;

frequency of the discharge pump: 20 Hz;

frequency of the metering pump: 30 Hz;

pressure of glue solution at an inlet of a metering pump: 3.3 MPa;

pressure of glue solution at an inlet of a metering pump: 2.5 MPa;

temperature of glue solution at outlet of metering pump: 104 ℃;

temperature of the coagulation bath: 18 ℃;

air gap air temperature: 10 ℃;

cooling wind speed: 5.0 m/s;

cooling air outlet humidity: 40 percent;

coagulation bath NMMO concentration: less than or equal to 30 percent;

spinning plate specification: 74400 × 0.095;

the glue solution conveying pipeline is heated and insulated by 3# electric heating oil.

Setting the temperature of a water chiller: 15 ℃ is prepared.

(5) And the post-treatment steps of water washing, cutting, oiling, drying and the like are as follows:

and stretching by a winding machine, washing by a washing machine, cutting by a cutting machine, oiling by a refining machine, and drying by steam of a drying machine after spinning to obtain the lyocell bamboo fiber.

The indexes of the finished product of the lyocell bamboo fiber are as follows: specification 1.33dtex 38mm, moisture regain 4.28%, dry breaking strength 3.35cN/dtex, wet breaking strength 2.91cN/dtex, 5% wet modulus 0.95cN/dtex, dry breaking elongation 10.1%, dry strength variation coefficient 8.2%, fineness deviation rate-2.6%, length deviation rate-2.1%, super length rate 1.9%, double length fiber 19mg/100g, coarse drawn yarn 32mg/100g, whiteness 72.6%, oil content 0.38%.

As described above, although the embodiments of the present invention have been described in detail, it will be apparent to those skilled in the art that many modifications are possible without substantially departing from the spirit and scope of the present invention. Therefore, such modifications are also all included in the scope of protection of the present invention.