CN113293474A

CN113293474A - Composite spinning process of plant yarn

Info

Publication number: CN113293474A
Application number: CN202110695543.XA
Authority: CN
Inventors: 金国周; 孙国军; 何林伟; 任勇梁; 江建峰; 杨杰; 应平; 郑国全
Original assignee: Shaoxing Guozhou Textile New Materials Co ltd
Current assignee: Shaoxing Guozhou Textile New Materials Co ltd
Priority date: 2020-09-29
Filing date: 2021-06-23
Publication date: 2021-08-24
Anticipated expiration: 2041-06-23
Also published as: CN113293474B; CN113249841B; CN113249842B; CN113638101B; CN113638101A; CN113249841A; CN113215702A; CN113293473B; CN113249842A; CN113293473A; CN113215702B

Abstract

The application provides a composite spinning process of plant yarns, and belongs to the technical field of products which are mainly characterized by adopting special yarn raw materials. The plant fiber is used as a raw material, the plant fiber is divided into two parts, a first loose fiber and a second loose fiber which have different color fastness and vividness are respectively dyed by adopting reactive dye and sulfur dye, and the first loose fiber and the second loose fiber are blended in proportion to form the plant yarn. Be applied to yarn processing with this application, have and wash old effect, and can realize washing more bright-colored special effect and present more, have advantages such as can not pollute workshop environment and equipment.

Description

Composite spinning process of plant yarn

Technical Field

The application relates to a composite spinning process of plant yarns, belonging to the technical field of products which are mainly characterized by adopting special yarn raw materials.

Background

The raw material composition of the plant yarn can adopt cotton, hemp or cotton/hemp, and multiple dyeing methods are superimposed to realize specialization and diversification of later-stage application in ways of over dyeing and the like, so that the reflection of different application requirements such as pseudo-classic effects is met. However, this method usually has the defects of serious fading, poor color fastness, too much washing water and the like.

Taking the denim which is applied more generally as an example, the denim is high in durability and universality, and in the processing and development process of the denim fabric, the denim is generally divided into two stages:

in the first period: the cloth product with jean washing effect is made by using sulfur dye to dye warp yarn through a sizing and dyeing combined machine, then weaving into fabric, and finally through washing, stone grinding and other modes.

And a second stage: the method comprises the steps of dyeing yarns by using a sulfur dye through a ball warp beam dyeing machine to prepare a fabric or a product, and finally preparing the product with the jean washing effect through methods such as water washing, stone grinding and the like.

However, the above methods have limitations on dyeing raw materials, and the products are single; the use of dyes such as indigo can be seriously retained in the surrounding environment in the dyeing and weaving process, and when the denim is dyed in the workshop, other fabrics can be dyed only if a great amount of cleaning work cannot be carried out or needs to be carried out; based on the requirement of the market for product diversity, in order to obtain clothes in a nostalgic or retro style, the dyed jean fabric dye is mostly fixed on the surface of the fiber, so that the exterior of the fiber is colored, the inner side of the fiber is always a white core, the color fastness is low/poor, natural fading forms an old-making effect in the washing process, and although the old-making effect is also achieved, the process and the old-making degree are not controllable.

Disclosure of Invention

In view of this, the application provides a composite spinning process for plant yarns, which not only introduces various yarns to realize composite blending, but also meets the requirements of old-fashioned fabrics and color fastness.

Specifically, the method is realized through the following scheme:

a composite spinning process for plant yarn uses plant fiber as raw material, the plant fiber is divided into two parts, the first and second loose fibers with different color fastness and brilliance are respectively formed by reactive dye dyeing and sulfur dye dyeing, and the first loose fiber and the second loose fiber are blended in proportion to form the plant yarn.

The plant yarn takes plant fiber as a raw material, two yarn components with different color fastness and vividness, namely a loose fiber I and a loose fiber II, are respectively formed by adopting different dyeing modes, and the loose fiber I is formed by dyeing the plant yarn by using reactive dye, so that the plant yarn has high color fastness and does not fade; the second loose fiber is a yarn raw material formed by dyeing plant yarns with sulfur dyes, the color fastness is poorer than that of the first loose fiber, and the first loose fiber and the second loose fiber are blended according to a set proportion to form a brand new mixed color plant yarn.

In the plant yarn, the sulfur dye and the reactive dye are respectively infected into the fiber, so that the result of dyeing inside and outside is presented, the dye is also widened from a single vat dye to the reactive dye, and the color fastness is improved; the color of part of the dyed part of the sulfur dye is darker, other dyeings are easy to suppress, and the dyed part of the sulfur dye has no vividness, so that the effect of washing old and vintage can be reflected, the plant fiber dyed by the active dye has good color fastness and high vividness (such as denim blue), the color fastness and the vividness are matched, the contrast is obvious, the integral color fastness of the plant yarn can be compensated, after the plant fiber is washed by water, the sulfur part fades along with the washing, the color and the vividness of the active dye are not suppressed, the active dyeing effect is highlighted, most of the finally left active dye is the active dye, when the two parts of the yarn are black, the yarn is black, the white washing effect is achieved at the moment, and when the two parts of the yarn have colors except black, the more washing and more vividness effects are achieved. The washing degree is different, and the washing effect is different, and is considerable relatively based on the colour fastness, through the control of washing degree, realizes the controllability of washing effect.

Further, as preferable:

the plant fiber is any one or the mixture of cotton fiber and hemp fiber. The plant fiber can be selected from pure fiber, namely the raw materials of the loose fiber I and the loose fiber II are both cotton fiber or fibrilia; mixed fibers can also be adopted, and the mixed fibers can adopt two forms in the composition: (1) one of the raw materials of the loose fiber I and the loose fiber II is cotton fiber, and the other one is fibrilia; (2) the plant fiber is a mixture of cotton fiber and fibrilia, and is divided into two parts which are respectively dyed by different dyes, so that a loose fiber I and a loose fiber II are formed. The preferred scheme of using cotton fiber and hemp fiber as plant fiber can give full play to the advantages of good skin-friendly property, good quality and easy availability, has good dyeing performance on different dyes, and can meet the dyeing requirements of different dyeing modes.

The mass ratio of the loose fiber I to the loose fiber II is 30-65: 70-35. The proportion of the first loose fiber and the second loose fiber not only meets the physical properties of strong stretching and the like, but also meets the requirements on appearance and color fastness. Although the process can be obtained through a large number of experiments, the workload is obviously very large by considering the influence of other factors, and in the selection of the mixture ratio, firstly, the influence of different mixture ratios on the effect of washing old and washing more bright is considered, and the requirement on the dyeing effect mainly comes from two aspects of the matching of different dyeing methods and the matching of the dyeing method and the plant fiber, and is embodied as the proportion problem of the dyeing part of the sulfur dye and the dyeing part of the reactive dye, and on the basis of the above, the effect on the physical performance is further considered, so that the proportion of the loose fiber I (the plant fiber dyed by the reactive dye) and the loose fiber II (the plant fiber dyed by the sulfur dye) is confirmed to be controlled to be 30-70:70:30, the effect is better, and the plant fiber can be formed by mixed fibers (namely one or more than one plant fibers), further perfection tests are carried out, and the effect is best when the mass ratio of the loose fiber I to the loose fiber II is 30-65: 70-35.

In the dyeing process, the core control parameters are dye concentration, dye liquor pH, treatment temperature and time length, and the applicant controls the dyeing parameters on the basis of the selected raw material plant fiber so as to meet the requirements on dyeing effect and mechanical performance. Thus, the core parameters for dyeing with reactive dyes and sulphur dyes are controlled as follows:

the dyeing process of the reactive dye comprises the following steps: 5-15 percent of reactive dye (owf) is used, the pH value of the dye liquor is 9-13, and the treatment is carried out for 50-80min at the temperature of 30-80 ℃. More preferably, the amount of the reactive dye is 6-8% (owf), the pH of the dye liquor is 11-12, and the treatment is carried out for 55-60min at 50-60 ℃.

The dyeing process of the sulfur dye comprises the following steps: the concentration of the sulfur dye is 10-30% (owf), the pH value of the dye liquor is 10-13, and the dyeing treatment is carried out for 50-80min at the temperature of 90-120 ℃. More preferably:

the dyeing process of the sulfur dye comprises the following steps: the concentration of the sulfur dye is 16-20% (owf), the pH value of the dye liquor is 11-12.5, and the dyeing treatment is carried out for 55-65min at the temperature of 95-105 ℃.

The sulfur dye is any one of sulfur dark blue 3R, sulfur Baolan CV, sulfur red brown B3R, sulfur ash, sulfur yellow brown 5G, sulfur red LGF, sulfur dark green 511, sulfur bright green 7713, sulfur dark brown GD, sulfur grass green 715, sulfur black BR, sulfur blue BRN, sulfur red sauce 3B or sulfur red GGF.

The dyeing of the sulfur dye and the reactive dye are matched, the color of the sulfur dye is relatively thick and dark, the color of the reactive dye is relatively obvious, the yarn obtained by adopting the composite spinning process is made into the denim fabric, the fiber of the sulfur dye is washed white in subsequent washing, and the fiber of the reactive dye cannot fade due to excellent washing fastness, so that the denim fabric can be processed into the effect that part of the fiber is washed white and the brightness is highlighted, namely the effect that the fiber is washed white and is bright. Especially for vulcanized black BR forming black jeans, the dyeing by the process is mainly reflected by a white washing effect, and the black degree of the vulcanized black is incomparable with other dyes.

In the above scheme, the following method can be adopted for further improvement: the composite fiber is characterized by also comprising a third loose fiber, wherein the third loose fiber is a natural plant fiber or is formed by dyeing the plant fiber with reactive dye or sulfur dye, and the mass ratio of the first loose fiber, the second loose fiber and the third loose fiber is 30-50:25-40: 10-30. More preferably, the mass ratio of the loose fiber I, the loose fiber II and the loose fiber III is 45:30: 25. The dry friction coefficient of the second loose fiber or the third loose fiber formed by dyeing with the sulfur dye is higher, partial fading can occur in the water washing treatment, but the fading is limited in the whitening process, and the pollution-free processing process can be realized, so the yarn forming effect is better.

The processing process of the application is divided into two parts: firstly, dyeing loose fibers: the plant fiber is matched with different dyeing methods to form two (or three) yarn forming raw materials with high color fastness and poor color fastness, and a foundation is provided for different fibers to show different effects in the subsequent washing and whitening processes; secondly, yarn forming: the yarn forming raw materials are in different proportions, and part of yarns of the color-spun jean yarn have an old washing effect, and have high color fastness, so that the integral color fastness is improved; the color that dyes dyeing such as vulcanization formed is dark partially, does not have the vividness, and the color fastness that dyeing such as reactive dye formed is good, the vividness is high, and both cooperate, and the contrast is obvious, and parts such as vulcanization fade along with the washing, and the most that finally leave are dyes such as reactive, make the surface fabric be and wash more vividly the effect more, different mill white degree, washing degree, different yarn ratios can form different surface fabric effects.

After the plant fiber is dyed by the reactive dye, the formed loose fiber has high color fastness and is not easy to fade in subsequent washing and whitening.

The vegetable fiber is dyed by the sulfur dye, so that the formed loose fiber has high dry friction coefficient, partial fading can occur in the water washing treatment, but the fading is limited in the whitening process, and a pollution-free processing process can be realized, so that the spinning effect is good.

In order to increase the product type and reduce the production cost, the plant yarn can also comprise a third loose fiber, the third loose fiber also takes plant fiber as raw material, the plant fiber can be used as natural color fiber without dyeing step to directly form yarn with the first loose fiber and the second loose fiber; or the plant fiber is dyed by sulfur dye or reactive dye, so that the color fastness of the first loose fiber, the second loose fiber and the third loose fiber is different, and the first loose fiber, the second loose fiber and the third loose fiber form plant yarns with various color fastness.

The conventional colored spun yarn processing process generally adopts a mode of multi-dye mixed dyeing, namely, after indigo or sulfur dyeing is carried out on yarns, reactive dye is used for over dyeing, and then spinning is carried out, the effect of the mode before water washing is better, but with the increase of the water washing times, the more the indigo or sulfur dyeing color is washed, the lighter the indigo or sulfur dyeing color is, and the whole colored spun yarn is in an old grey state; in the scheme, the plant fiber is divided into two parts (when the plant fiber with the natural color exists, the plant fiber is divided into three parts, and the third part is not subjected to a dyeing process), one part of the plant fiber is dyed by the reactive/sulfur dye, the other part of the plant fiber is dyed by the sulfur/reactive dye, two (or three) formed raw materials form yarn, the formed finished product plant yarn part has an old washing effect, the color fastness of the part is high, and the integral color fastness is improved; the color that the sulphur dyestuff dyeing formed is dark, does not have the vividness, and the colour fastness that the reactive dye dyeing formed is good, the vividness is high, and both cooperate, and the contrast is obvious, and the part of vulcanizing fades along with the washing, and the active dye that finally leaves is mostly, and the surface fabric is and washes more bright-colored effect more.

Drawings

FIG. 1 is a comparison graph of the effect of the black denim fabric woven by the yarn of the present application before and after washing;

FIG. 2 is a comparison graph of the effect of the denim blue fabric woven by the yarn of the present application before and after washing;

FIG. 3 is an appearance view of a fabric woven with the yarns of the present application.

Detailed Description

The flow of this example is summarized as follows:

the plant fiber is used as a raw material and is divided into two parts:

dyeing a part of plant fibers by using reactive dye to form a loose fiber I;

dyeing a part of plant fibers by using a sulfur dye to form a loose fiber II;

and blending the loose fiber I and the loose fiber II to form the yarn of the denim color.

Wherein, the parameters influencing the effect of the plant yarn are divided into the following parts:

(1) raw materials. (2) Proportioning.

(3) Influence of dyeing process conditions: the plant fiber can be dyed by sulfur dye and also can be dyed by reactive dye, so the dyeing process has the following important points: firstly, different influences of a dyeing process on fibrilia and cotton fiber are caused; ② the influence of different dyeing processes on the finished yarn. Here, the raw materials are combined for comprehensive evaluation.

(4) Selection of yarn forming mode: ring spinning, rotor spinning, air jet spinning and vortex compact spinning.

The following combination cases were analyzed for specific parameters.

Example 1: effect of different fibers on plant yarn Performance

The plant fiber mainly adopts hemp fiber (in the application, the plant yarn is mainly used for spinning, therefore, the hemp fiber mainly adopts ramie, hemp, flax, apocynum venetum and the like) and cotton fiber, therefore, the plant yarn has three forms:

firstly, the loose fiber I and the loose fiber II adopt the fibrilia simultaneously to form pure fibrilia series,

secondly, the first loose fiber and the second loose fiber adopt cotton fiber at the same time to form a pure cotton series,

thirdly, the loose fiber I and the loose fiber II adopt fibrilia and cotton fiber to form a cotton-flax series.

Combining different dyeing methods, plant yarns of several compositions as shown in table 1 were formed.

TABLE 1 construction of plant yarn

The table 1 provides the dyed plant yarns of the pure cotton series, the pure linen series and the cotton linen series respectively, and the fabric formed by the pure cotton series has the advantages of good moisture absorption and heat resistance, wearing comfort and the like; the pure hemp series has the characteristics of good hygroscopicity, quick moisture permeability, allergy resistance, static resistance, light weight and the like; the cotton-flax series has soft texture, warmness in winter and coolness in summer and excellent permeability, can effectively adsorb sweat and slight sweat on human skin, really achieves the effects of ventilation and sweat absorption, endows the yarn with soft color due to the individual difference of cotton and flax in active dyeing and vulcanization dyeing, and particularly has better use effect due to the matching of cotton and flax.

Example 2: effect of different ratios on plant yarn Performance

In this embodiment, the plant yarn is divided into two forms:

(1) the loose fibers I and the loose fibers II; (2) the first loose fiber, the second loose fiber and the third loose fiber.

In the following, the influence of the compounding ratio was compared and analyzed, as represented by numbers 1, 2 and 11 in table 1.

1. The process flow comprises the following steps: the method is characterized in that cotton fiber is used as a raw material and divided into two parts, one part of the cotton fiber is dyed by reactive dye to form a loose fiber I, the other part of the cotton fiber is dyed by sulfur dye to form a loose fiber II, and the loose fiber I and the loose fiber II are spun by ring spinning to obtain the plant yarn.

2. Description of the parameters

(1) 1, loose fiber I: activity black W-N8% (o.w.f), pH11.5, 60 ℃, 60 min.

(2) And (2) loose fibers: black sulphide BR 18% (o.w.f), pH 12.5, 100 ℃ for 60 min.

(3) The ring spinning process conditions are as follows: the low-speed vortex spinning is adopted, the speed is controlled at 350m/min, the feeding ratio is 0.97, so that cohesive force is reduced, the glittering effect is increased, and the drafting in the rear zone is properly reduced, so that accidental drafting is controlled.

(4) The proportion of the first loose fibers to the second loose fibers is as follows: experiments were conducted in which plant yarns were constructed in two colors (two dyeing modes, i.e., active dyeing and vulcanization dyeing, and not limited to two colors for dyeing) using the respective ratios of the first loose fibers to the second loose fibers (mass ratios of the first loose fibers to the second loose fibers) as represented by 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, and 90: 10.

The experimental structure shows that: the characteristics based on different components are more obvious, such as higher color fastness and bright color of fibers dyed by the reactive dye, the fabric is suitable for being made into bright yarn and finished cloth, and the effects of fading, old color making, white grinding (which is the requirement of denim yarn on color) and the like are not ideal enough; the color of the sulfur dye is dark, and the color is not bright; the control of the ratio must therefore be very critical to ensure compatibility in appearance and compatibility in physical properties. When the mass ratio of the first loose fiber to the second loose fiber is 30-65:70-35, the first loose fiber and the second loose fiber have good matching effect, the color fastness of cloth woven by the plant yarn is more than 4 grade, the surface can realize the effects of pocking, washing and the like, in addition, in the using washing process, when parts such as vulcanization and the like are faded along with the washing, most of the finally remained dyes such as activity and the like are obvious in contrast, so that the fabric has the effect of being more bright-colored when being washed, and the defect of dark color is overcome while the effect of the vulcanized parts is exerted.

Further, experiments were also conducted on the three-color composition of the pure cotton series, and three-color (including active dyeing, vulcanization dyeing and natural color, but not limited to three colors) was performed using the ratios (mass ratios) of the first loose fiber, the second loose fiber and the third loose fiber as representatives of 10:80:10, 20:70:10, 25:65:10, 30:60:10, 30:50:20, 20:60:20, 25:55:20, 25:50:25, 30:45:25, 35:40:25, 40:35:25, 45:30:25, 45:25:30, 50:20:30 and 60:10:30, respectively. A trend similar to dichroism appears: the effect is better when the mass ratio of the loose fiber I, the loose fiber II and the loose fiber III is 30-50:25-40: 10-30.

Indigo dyeing can only dye the surface layer, and the inner core is still white; the method can realize the dye-through effect, and both inside and outside are provided with the dye.

Example 3: effect of different dyeing processes on the Linear behavior of plant yarns

Taking the scheme with the number 1 in table 1 as an example,

the loose fibers are formed by dyeing cotton fibers with reactive dyes, the loose fibers are formed by dyeing the cotton fibers with sulfur dyes, the two loose fibers are blended into yarns to form the denim colored yarns, the yarns are spun by ring spinning, and then the denim fabric is woven by a warp knitting mode.

The dyeing process of the reactive dye comprises the following steps: 5-15% (such as 5%, 6%, 8%, 10%, 11.5%, 12%, 13%, 14%, 15%) of reactive dye, 9-13 (such as 9, 10, 11, 11.5, 12) of dye solution, 50-80% (such as 30 ℃, 40 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 80 ℃) of treatment for 50-80min (such as 50min, 55min, 60min, 65min, 70min, 80min), 6-8% (owf) of reactive dye, 11-12% of dye solution, and 55-60 ℃ of treatment for 55-60min, wherein the reactive dye dyeing process is not only suitable for the cotton fibers, but also suitable for the hemp fibers.

The dyeing process of the sulfur dye comprises the following steps: the sulfur dye concentration is 10-30% (such as 10%, 12%, 15%, 18%, 20%, 22%, 25%, 30%), the dye solution pH is 10-13 (such as 10, 11, 11.5, 12, 12.5, 13), the dyeing treatment is 50-80min (such as 50min, 55min, 60min, 65min, 70min, 80min) at 90-120 ℃ (such as 85 ℃, 90 ℃, 95 ℃, 100 ℃, 102 ℃, 105 ℃, 110 ℃, 120 ℃), the sulfur dye dosage is 16-20% (owf), the dye solution pH is 11-12.5, and the dyeing treatment is 55-65min at 95-105 ℃, the sulfur dyeing process is not only suitable for the cotton fiber, but also suitable for the hemp fiber.

Wherein the sulfur dye can be selected from any one of commercially available deep blue sulfide 3R, Baolan sulfide CV, red brown sulfide B3R, sulfur ash, yellow brown sulfide 5G, red LGF sulfide, dark green sulfide 511, bright green sulfide 7713, dark brown sulfide GD, grass green sulfide 715, black BR sulfide, blue BRN sulfide, red sauce sulfide 3B or red GGF sulfide.

The dyed yarns were subjected to a color fastness test using a black dye as an example, and the results are shown in table 2.

TABLE 2 color fastness of vegetable yarns under different dyeing processes

The color fastness of the formed cloth is more than 4 grade, the fibers dyed by different dyes are different in dyeing rate of cotton and hemp, the surfaces of the final plant yarns (such as the plant yarns corresponding to the serial numbers 1, 2 and 3 in the table 2) obtained by the method can have pockmarks, after the fibers are woven, the characteristics can be extended to the fabric shown in the figure 3 (the pockmarks are also present at different color depth positions of the fabric), the effects of vintage, washing old and the like are embodied, in the washing process, parts such as vulcanization and the like are washed away with water, most of the finally left dyes such as active dyes are faded, the contrast is obvious, and the fabric has the effect of being more bright-colored when being washed.

The above trends have the same or less different trends for the other protocols in table 1.

Compared with the conventional over-dyeing (cotton fiber and cotton-flax fiber) mode, the scheme avoids the use of a large amount of sulfur dyes which are easy to discolor, not only solves the biggest problem of waste water in the printing and dyeing field, but also realizes the special effect that the final black jeans are washed white and worn as shown in figure 1, and the colorful fabrics are more bright as shown in figure 2 while keeping the special effect of the sulfur dyes in the fields of jeans and the like through the matching of the plant fibers and different dyeing methods and the matching property of the fibers after different dyeing.

The plant yarn formed by the scheme is used for colored jeans (such as jean blue), the yarn can be endowed with a dark effect in a vulcanization dyeing mode, the color is dense, the color of other dyes can be easily suppressed, the plant fiber is dyed brightly by vat dye, the vulcanized dye is not suppressed with bright color difference such as active dye after washing, the active dyeing effect is highlighted, and the yarn and the fabric woven by the yarn can be endowed with a bright color effect; on black jeans, the whitening effect is shown.

Claims

1. A composite spinning process of plant yarn is characterized in that: the plant fiber is used as a raw material, the plant fiber is divided into two parts, a first loose fiber and a second loose fiber which are different in color fastness and brightness are respectively dyed by adopting reactive dyes and sulfur dyes, the first loose fiber and the second loose fiber are blended in proportion to form plant yarns, the plant yarns are divided into black yarns and color yarns according to different color compositions, the color yarns have a more bright effect when being washed, and the black yarns have a white washing effect.

2. The composite spinning process of plant yarn as claimed in claim 1, wherein: the plant fiber is any one or the mixture of cotton fiber and hemp fiber.

3. The composite spinning process of plant yarn as claimed in claim 1, wherein: the mass ratio of the loose fiber I to the loose fiber II is 30-65: 70-35.

4. The composite spinning process of plant yarn as claimed in claim 1, wherein the reactive dye dyeing process is as follows: 5-15% of reactive dye, 9-13 of dye liquor pH, and 50-80min of treatment at 30-80 ℃.

5. The composite spinning process of plant yarn as claimed in claim 4, wherein: the active dye is used in 6-8 wt%, the dye solution has pH value of 11-12, and the dye solution is treated at 50-60 deg.c for 55-60 min.

6. The composite spinning process of plant yarn as claimed in claim 1, wherein the sulfur dye dyeing process: the usage amount of the sulfur dye is 10-30%, the pH value of the dye solution is 10-13, and the dyeing treatment is carried out for 50-80min at the temperature of 90-120 ℃.

7. The composite spinning process of plant yarn as claimed in claim 6, wherein the sulfur dye dyeing process: the usage amount of the sulfur dye is 16-20%, the pH value of the dye solution is 11-12.5, and the dyeing treatment is carried out for 55-65min at the temperature of 95-105 ℃.

8. The composite spinning process of plant yarn as claimed in claim 6, wherein the sulfur dye is any one of deep blue sulfide 3R, Baolan sulfide CV, red brown sulfide B3R, sulfur ash, yellow brown sulfide 5G, red LGF, dark green sulfide 511, bright green sulfide 7713, dark brown sulfide GD, grass green sulfide 715, black BR sulfide, blue BRN, red sauce sulfide 3B or red GGF.

9. A composite spinning process of plant yarn according to any one of claims 1 to 8, characterized in that: the composite fiber is characterized by also comprising a third loose fiber, wherein the third loose fiber is a natural plant fiber or is formed by dyeing the plant fiber with reactive dye or sulfur dye, and the mass ratio of the first loose fiber, the second loose fiber and the third loose fiber is 30-50:25-40: 10-30.

10. The composite spinning process of plant yarn as claimed in claim 9, wherein: the mass ratio of the loose fiber I, the loose fiber II and the loose fiber III is 45:30: 25.