Dyeing and dehairing one-bath finishing process for China-hemp cotton knitted fabric

Abstract

The invention discloses a dyeing and dehairing one-bath finishing process for China-hemp cotton knitted fabric. The dyeing and dehairing one-bath finishing process comprises the following steps: (1) preparing gray fabric; (2) greige cloth rinsing: cleaning impurities and stains on the surface of the greige cloth in advance, and promoting preliminary wetting and swelling among yarns and fibers at the same time; (3) pretreatment; neutral cellulase with the concentration of 0.25-0.5% (o.w.f) is added into the dye vat, the bath ratio is 1: 15, the treatment temperature is 55-58 DEG C, and the treatment time is 45-60 min; (5) dyeing; (6) washing; and (7) tentering and drying. The wool removing process and the dyeing and finishing process are organically combined, the problems of strength, creases, scratches, discoloration, manpower and the like existing in an existing knitted fabric wool removing process are solved, milder neutral cellulase is selected to replace acid cellulase, the influence on the strength of cellulose is smaller, the wool removing process and the dyeing and finishing process are organically combined, and the dyeing and finishing effects are better. And the dehairing process is completed during pretreatment, so that the subsequent dyeing is not influenced, and the influence of cellulase on the color is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of textile dyeing and finishing, and in particular relates to a one-bath finishing process for dyeing and depilating hemp-cotton knitted fabrics. Background Art

[0002] With the improvement of people's living standards and changes in consumption concepts, the cotton and linen textile industry has become an important fabric industry in the textile industry, supplying a large amount of raw materials to the global textile market. As consumers become increasingly picky and adopt high-standard lifestyles, the production technology of cotton and linen textiles is also constantly upgraded with quality requirements.

[0003] Among them, hemp cotton knitted fabrics are widely used in clothing, home decoration and other fields due to their softness, comfort, good elasticity, wear resistance, wrinkle resistance, breathability and strong moisture absorption. At present, the conventional dyeing and finishing process of cotton and linen knitted fabrics mainly includes the following steps: grey cloth preparation → singeing → pretreatment → desizing → scouring → dyeing → post-treatment. However, during the production process, floating hair and fiber impurities often remain on the surface of hemp cotton knitted fabrics, which not only affect the appearance of the product, but also may cause skin discomfort to consumers and reduce the wearing experience. Traditional depilation methods such as mechanical brushing and chemical depilation have problems such as damaging fabric fibers, affecting color fastness or environmental pollution. The existing dyeing, finishing and depilation technologies for cotton and linen fabrics are as follows:

[0004] CN116356575A discloses a cotton and linen textile fabric and a preparation process thereof; the preparation process comprises the following steps: S1: pretreatment; the cotton and linen fibers are placed in a hydrogen peroxide solution for low-temperature bleaching for 50-60 minutes, and the temperature is controlled at 80°C; S2: mercerizing; the cotton and linen fibers are then placed in a concentrated sodium hydroxide solution for mercerizing for 1 minute, and during the mercerizing process, the concentration of the sodium hydroxide solution is controlled at 150-170g / l and the temperature is 20-25°C.

[0005] CN107151928A discloses a preparation process of cotton and linen blended dyed fabric, which mainly includes the following steps: preparation of grey cloth, singeing, pretreatment, desizing, scouring and bleaching, dyeing and post-treatment; wherein the pretreatment operation is hydrothermal pressure treatment, with a bath ratio of 1:10-15, a temperature of 135-150°C, a pressure of 0.2-0.3MPa, and a treatment time of 20-30min; the desizing operation is to add cellulase, amylase, nonionic surfactant and cysteamine simultaneously in warm water at 55-60°C, and control the pH value to 5.5-6 and the bath ratio to 1:10-15; the scouring and bleaching operations are to scour in a high-temperature concentrated alkaline solution, to which caustic soda, hydrogen peroxide and anti-wrinkle agent are added; the dyeing operation is to first put the grey cloth into warm water with a bath ratio of 1:15-20, add a buffer and a carrier auxiliary agent, and then add a dye after 15min for high-temperature and high-pressure dyeing.

[0006] CN110565313A discloses a double-sided depilatory device for linen fabrics, comprising a collecting box, a wheel axle fixedly mounted between the front and back sides of the inner wall of the collecting box, a cleaning rod fixedly mounted on the wheel axle, a cleaning brush head fixedly mounted on one end of the cleaning rod, and a depilatory rod fixedly mounted on the wheel axle. Through the elastic material of the brush rod, the lower surface depilatory brush and the linen yarn moving towards each other, and the lower surface depilatory brush being easy to contact with the linen yarn in the vertical direction before rotating to the linen yarn, the hair balls on the brush rod can be cleaned from the hair balls on the lower surface of the linen yarn under a certain pressure on the linen yarn.

[0007] It can be seen from the above patent technology that the existing technology uses mechanical dehairing and singeing to remove the fluff and floating hair on the surface of the fabric. However, due to the special structure of hemp fiber, it has more hair than flax. Although the hair on the surface of the fabric can be removed, the hair inside the fabric cannot be removed, which is still easy to affect the dyeing effect of the fabric during dyeing. At the same time, the mechanical dehairing method is also easy to damage the fiber. The acidic environment in the desizing process is easy to cause significant damage to the strength of hemp, cotton and other fibers. The above defects lead to some defects in the current dyeing and finishing process of hemp cotton knitted fabrics.

[0008] At present, the process widely used in dyeing and finishing workshops is to remove the hair of the garment or fabric by cellulase after dyeing the knitted fabric, and adopt the washing tank process. The limitations of this process are:

[0009] 1. The equipment uses a water washing tank. It is difficult to control the amount of cloth put into each tank, and the capacity of the tank is limited. The washed fabrics are easily stretched and tangled in the tank, resulting in uneven hair removal and even creases, abrasions and deformation.

[0010] 2. This process mostly uses acidic cellulase, which has an impact on the strength of cellulose such as hemp cotton under acidic conditions. Combined with the strength-reducing effect of cellulase, this process has a great impact on the strength of the fabric.

[0011] 3. After dyeing, knitted fabrics are treated with acid cellulose, because the pH value is low, the color will change to a certain extent after treatment, especially for sensitive colors. This will affect the color control of bulk goods and increase the cost of color repair.

[0012] 4. This treatment process is relatively independent. After treatment, the fabric needs to be manually pulled out of the washing tank and manually smoothed, which is labor-intensive and inefficient.

[0013] In view of this, how to solve the problem of the existing acid cellulose enzyme dehairing technology causing a strong impact on linen and cotton knitted fabrics, avoid uneven dehairing of cotton and linen knitted fabrics and creases, abrasions and deformation, and at the same time, solve the problem of the impact of the acidic environment on the color and color of the finished garments, improve production efficiency and reduce production process costs. This has become a difficult problem that technicians in the field of dyeing and finishing of hemp and cotton knitted fabrics urgently need to solve. Summary of the invention

[0014] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a one-bath dyeing and depilation finishing process for hemp-cotton knitted fabrics which combines a depilation process with a dyeing and finishing process to achieve the purpose of simultaneous dyeing and depilation while minimizing fiber damage and improving production efficiency.

[0015] In order to solve the above technical problems, the technical solution adopted by the present invention is: a dyeing and depilatory one-bath finishing process for hemp-cotton knitted fabrics, comprising the following steps:

[0016] (1) Grey fabric preparation: Select knitted fabric blended with hemp fiber and cotton fiber as grey fabric and set aside;

[0017] (2) Grey cloth washing: pre-wash to remove impurities and stains on the surface of the grey cloth, and at the same time promote initial wetting and swelling between yarns and fibers;

[0018] (3) Pretreatment: After rinsing, the grey cloth is treated with a degreasing agent, a refining agent, caustic soda, and hydrogen peroxide to further remove the grey cloth slurry and stubborn oil stains, while further fully swelling the fibers;

[0019] (4) Hair removal: Add 0.25-0.5% (owf) neutral cellulase into the dye vat, bath ratio 1:15, treatment temperature 55-58°C, treatment time 45-60 min;

[0020] (5) Dyeing: According to the dyeing requirements, the grey cloth after hair removal is overflow dyed by using reactive dyeing process;

[0021] (6) Flushing: After the fabric is dyed and taken out of the vat, it is placed in a flushing tank. The hair attached to the fabric is removed by multiple high-pressure water guns inside the flushing tank.

[0022] (7) Tenter drying: Dry the linen-cotton knitted fabric fully to stabilize the width and weight.

[0023] In the above-mentioned one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric, in the step (4), the concentration of neutral cellulase is 0.4% (owf), the treatment temperature is 58° C., and the treatment time is 50 min.

[0024] In the above-mentioned one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric, in the step (4), the heating rate is 2-4°C / min.

[0025] In the above-mentioned one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric, in the step (4), the activity of the neutral cellulase is 11240.

[0026] In the above-mentioned one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric, in the step (4), the neutral cellulase is any one of the neutral deoxidizing polishing enzyme TF161LC, the cellulase Neupolish 8000L, and the neutral depilatory agent QTQ-102.

[0027] In the above-mentioned dyeing and depilatory one-bath finishing process for hemp-cotton knitted fabric, after the completion of step (7), the grey fabric is pre-shrunk. Under the action of steam in the pre-shrinking machine, the hemp-cotton knitted fabric runs without tension, so that the stress inside the fabric is fully released, thereby improving the shrinkage rate of the fabric.

[0028] The advantages of the dyeing and depilation one-bath finishing process of hemp-cotton knitted fabrics of the present invention are: it solves the problem of obvious strength reduction of hemp-cotton knitted fabrics in the existing acid cellulase depilation technology, and replaces the acid cellulase of the original process with neutral cellulase. In view of the unstable depilation effect of the original technology and the problems of creases and color change that are easy to occur during the depilation process, the original relatively independent depilation process is organically combined with the conventional dyeing process, and the depilation process is integrated with the dyeing and finishing process, so that the depilation process is carried out in the dyeing machine to replace the washing tank. Because the capacity of the dyeing machine is larger than that of the washing tank, the fabric and the cellulase are more fully in contact with each other in the dyeing machine and are not easy to be knotted, and the mutual friction with the equipment is small, thereby solving the problems of unstable depilation effect, uneven depilation creases, color change, strength and water and electricity energy saving in the existing enzyme depilation technology and the washing tank, and improving the overall quality of the knitted fabrics. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the dyeing and depilatory one-bath finishing process of the present invention;

[0030] Figure 2 It is a curve chart showing the effect of different treatment times on force value under the same enzyme concentration condition;

[0031] Figure 3 (a) and (b) are actual comparison pictures of the un-depilated hemp-cotton knitted fabric and the hemp-cotton knitted fabric prepared in Example 4 at different visual angles. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] In the present invention, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the attached drawings; while "inside" and "outside" refer to the outline of the device. In addition, in the description of this application, the term "including" means "including but not limited to". The terms first, second, third, etc. are used only as labels and do not impose numerical requirements or establish an order. The term "plurality" means "two or more".

[0034] like Figure 1 As shown, a one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric comprises the following steps:

[0035] (1) Grey fabric preparation: Select knitted fabric blended with hemp fiber and cotton fiber as the grey fabric and set aside;

[0036] (2) Grey cloth washing: pre-wash to remove impurities and stains on the surface of the grey cloth, and at the same time promote initial wetting and swelling between yarns and fibers;

[0037] (3) Pretreatment: After rinsing, the grey cloth is treated with a degreasing agent, a refining agent, caustic soda, and hydrogen peroxide to further remove the grey cloth slurry and stubborn oil stains, while further fully swelling the fibers;

[0038] (4) Hair removal: Add 0.25-0.5% (owf) neutral cellulase into the dye vat, bath ratio 1:15, treatment temperature 55-58°C, treatment time 45-60 min;

[0039] (5) Dyeing: According to the dyeing requirements, the grey cloth after hair removal is overflow dyed by using reactive dyeing process;

[0040] (6) Flushing: After the fabric is dyed and taken out of the vat, it is placed in a flushing tank. The hair attached to the fabric is removed by multiple high-pressure water guns inside the flushing tank.

[0041] (7) Tenter drying: Dry the linen-cotton knitted fabric fully to stabilize the width and weight.

[0042] Wherein, the grey cloth of the present invention is a hemp-cotton knitted cloth, which is composed of 55% hemp and 45% cotton, and the organization is a single-sided plain needle structure. The activity of neutral cellulase is 11240, and the neutral cellulase is any one of neutral cellulase EVCLEAN MS, neutral deoxidation polishing enzyme TF161LC, fiber softening enzyme Neupolish 8000L, and neutral etching agent QTQ-102. Due to the special structure of hemp fiber, it has more hairiness. In order to be able to remove the hairiness on the surface and inside of the fabric, in the dehairing process, the temperature is slowly heated and controlled, and the heating rate is controlled to 2-4°C / min, which can make the neutral cellulase have enough time to enter between the yarns and between the fibers after wetting and swelling, and effectively improve the dehairing effect. After the stenter drying is completed, the present invention performs pre-shrinking treatment on the grey cloth. Under the action of steam in the pre-shrinking machine, the hemp-cotton knitted fabric runs without tension, so that the stress in the fabric is fully released, and the shrinkage rate of the fabric is improved. At the same time, since a neutral environment is used for hair removal, the color can be fixed directly in the color fixing stage after dyeing is completed without acid-base neutralization, which reduces production costs, reduces processes, and improves production efficiency. Moreover, the hair removal process can be combined with a variety of dyeing processes and is not restricted by specific dyes and other auxiliaries in the dye solution. All fabrics that meet the dyeing requirements of neutral dye solutions can be used.

[0043] The present invention organically combines the dehairing process with the dyeing and finishing process, solves the problems of strength, creases, abrasions, color change and manpower in the existing knitted fabric dehairing process, and selects milder neutral cellulase to replace acid cellulase; because neutral cellulase is suitable for the process conditions of pH=6-7, it has less influence on the strength of cellulose, and organically combines the dehairing process with the dyeing and finishing process, completes the dehairing process during pretreatment, does not affect subsequent dyeing, and avoids the influence of cellulase on color. And there is no need to arrange manual labor to drag the treated fabric out of the tank, thereby reducing the labor intensity of workers.

[0044] The present application is described in detail below through specific embodiments. The following embodiments are only partial embodiments of the present application and are not limitations of the present application.

[0045] Example 1

[0046] A one-bath finishing process for dyeing and depilating hemp-cotton knitted fabrics, comprising the following steps:

[0047] (1) Grey fabric preparation: Select knitted fabric blended with hemp fiber and cotton fiber as the grey fabric and set aside;

[0048] (2) Grey cloth rinse: The preparation work before the grey cloth is smelted and bleached after entering the tank. Penetrants and detergents are added during rinse to remove impurities and stains on the surface of the grey cloth in advance, and to initially wet and swell the yarns and fibers, which is beneficial to pre-treatment processing;

[0049] (3) Pretreatment: After rinsing, the grey cloth is treated with a degreasing agent, a refining agent, caustic soda, and hydrogen peroxide to further remove the grey cloth sizing and stubborn oil stains, while allowing the fiber to fully swell, which is beneficial for dyeing and finishing. At the same time, under the action of hydrogen peroxide, the whiteness of the fabric is increased to meet the dyeing requirements. This step achieves the purpose of completing desizing, scouring, and bleaching in one bath;

[0050] (4) Hair removal: Add neutral cellulase EVCLEAN MS with an activity of 11240 and a concentration of 0.4% (owf) into the dye vat, with a bath ratio of 1:15, and a heating rate of 2°C / min to a temperature of 55°C for 60 min. This step removes the floating hair on the surface and inside of the linen and cotton knitted fabric before dyeing it through the combined action of the neutral cellulase and the relative movement between the water flow in the dye vat and the fabric;

[0051] (5) Dyeing: According to the dyeing requirements, the grey cloth after hair removal is overflow dyed by using reactive dyeing process;

[0052] (6) Flushing: After dyeing and dehairing, the hairs of the fabric fall off the fabric surface after the cellulase reaction and circulate with the dye solution in the vat. Some of the hairs will adhere to the fabric surface and need to be removed by mechanical action in the flushing step. In this process, after the fabric is dyed and opened, the fabric is placed in the flushing tank, and the hairs adhering to the fabric surface are removed by the high-pressure water gun inside the flushing tank;

[0053] (7) Tenter drying: fully dry the linen-cotton knitted fabric to stabilize the width and weight;

[0054] (8) Preshrinkage: Under the action of steam in the preshrinkage machine, the linen and cotton knitted fabric runs without tension, so that the stress inside the fabric is fully released, thus improving the shrinkage of the fabric.

[0055] Example 2

[0056] The similarities between this embodiment and embodiment 1 are not repeated here, and the differences are as follows: (4) Dehairing: Add 0.5% (owf) neutral cellulase EVCLEAN MS into the dye vat, with a bath ratio of 1:15, and a heating rate of 3°C / min to 56°C for 45 min.

[0057] Example 3

[0058] The similarities between this embodiment and embodiment 1 are not repeated here, and the differences are as follows: (4) Dehairing: Add 0.25% (owf) neutral cellulase EVCLEAN MS into the dye vat, with a bath ratio of 1:15, a heating rate of 3°C / min, and the temperature is raised to 58°C for 60 min.

[0059] Example 4

[0060] The similarities between this embodiment and embodiment 1 are not repeated here. The difference lies in that in step (4), the concentration of neutral cellulase EVCLEAN MS is 0.4% (owf), the bath ratio is 1:15, the heating rate is 4°C / min, the temperature is raised to 58°C, and the treatment time is 50min.

[0061] The performance test results of the linen-cotton knitted fabric obtained by the dyeing and depilation one-bath finishing process of the present invention are as follows:

[0062] like Figure 2 As shown in the figure, the effect of different treatment times on the force value under the same concentration of neutral cellulase EVCLEAN MS was tested, combined with Figure 2 It can be obtained that the reaction begins to be intense at the 45-60 minute stage, and this time period coincides with the dyeing time. In order to ensure that the dyeing can be carried out simultaneously with the dehairing treatment and the dehairing treatment process is gentle and efficient, and considering the overall performance of the knitted fabric, the dyeing one-bath treatment time of the present invention is set at 50 minutes, and the selection of other parameters is based on Example 4 as the best embodiment.

[0063]

[0064] From the data analysis in Table 1 above, it can be seen that the un-dehaired hemp-cotton knitted fabric has a high strength value, heavy hairiness on the fabric surface, and poor resistance to pilling. The hemp-cotton knitted fabric of Example 1 has a smooth surface, good dehairing effect, and meets the standard for anti-pilling, strength, and appropriate process conditions. The hemp-cotton knitted fabric of Example 2 has a smooth surface, good dehairing effect, and meets the standard for anti-pilling. The strength meets the standard but is at a lower level, and the process conditions are slightly heavy. The hemp-cotton knitted fabric of Example 3 has a relatively smooth surface with less hairiness, a decent dehairing effect, and meets the standard for anti-pilling, a high strength value, and slightly light process conditions. The hemp-cotton knitted fabric of Example 4 has a smooth surface, good dehairing effect, and meets the standard for anti-pilling, strength, and appropriate process conditions.

[0065] Compare the changes in fabric strength and pilling resistance obtained by different concentrations of cellulase (enzyme), treatment time and treatment temperature of the undepilated and Examples 1-4, and combine Figure 3 (a) Figure 3 (b) The obtained knitted fabric pictures at different visual angles show that when the cellulase (enzyme) concentration is 0.25-0.5% (owf), the treatment time is controlled at 45-60min, and the treatment temperature is 55-58°C, a relatively smooth fabric surface effect can be obtained, and the fabric strength is less affected. It can be seen that the process of the present invention has an obvious depilation effect on hemp cotton knitted fabrics, and can also ensure the strength of hemp cotton knitted fabrics. The removal of hairiness also significantly improves the anti-pilling performance of hemp cotton knitted fabrics.

[0066] The process of the present invention is to perform hair removal treatment on the hemp-cotton knitted fabric before dyeing, which does not affect the subsequent dyeing process, and the cellulase will not affect the fuel, so the color repetition rate is significantly improved compared with the hair removal process after dyeing. A milder neutral cellulase is used to replace the acid cellulase, and all hair removal processes are carried out under neutral conditions. Because the neutral enzyme is suitable for the process conditions of pH=6-7, it matches the process conditions of active dyeing. The dyeing stage is carried out synchronously with the hair removal process, and the dyeing alkali fixation stage is carried out synchronously with the inactivation process. The entire hair removal process can be carried out synchronously with the dyeing process. The damage to cellulose is greatly reduced. The dyeing and finishing process is organically combined with the hair removal process and carried out synchronously. Compared with the cellulase hair removal process after dyeing, the color of the fabric is easier to control and more stable. The dyeing and cellulase hair removal are combined and carried out synchronously. The equipment adopts a conventional airflow or overflow dyeing machine, and the space in the cylinder is large, and it is not easy to produce creases. Moreover, the process is not independent, but is carried out synchronously with the dyeing. Compared with the existing traditional process, the process flow is shortened, the production efficiency is improved, and the water and electricity energy consumption is effectively reduced.

[0067] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A one-bath finishing process for dyeing and depilating hemp-cotton knitted fabrics, characterized in that: The steps include: (1) Grey fabric preparation: Select knitted fabric blended with hemp fiber and cotton fiber as the grey fabric and set aside; (2) Grey cloth washing: pre-wash to remove impurities and stains on the surface of the grey cloth, and at the same time promote initial wetting and swelling between yarns and fibers; (3) Pretreatment: After rinsing, the grey cloth is treated with a degreasing agent, a refining agent, caustic soda, and hydrogen peroxide to further remove the grey cloth slurry and stubborn oil stains, while further fully swelling the fibers; (4) Dehairing: Add 0.25-0.5% (owf) neutral cellulase into the dye vat, bath ratio 1:15, treatment temperature 55-58°C, treatment time 45-60 min; (5) Dyeing: According to the dyeing requirements, the grey cloth after hair removal is overflow dyed by using reactive dyeing process; (6) Flushing: After the fabric is dyed and taken out of the vat, it is placed in a flushing tank. The hair attached to the fabric is removed by multiple high-pressure water guns inside the flushing tank. (7) Tenter drying: Dry the linen-cotton knitted fabric fully to stabilize the width and weight.

2. The one-bath dyeing and depilatory finishing process for hemp-cotton knitted fabric according to claim 1, characterized in that: In the step (4), the concentration of the neutral cellulase is 0.4% (owf), the treatment temperature is 58° C., and the treatment time is 50 min.

3. The one-bath finishing process for dyeing and depilating hemp-cotton knitted fabric according to claim 1, characterized in that: In the step (4), the heating rate is 2-4°C / min.

4. The one-bath dyeing and depilatory finishing process for hemp-cotton knitted fabric according to claim 1, characterized in that: In the step (4), the activity of the neutral cellulase is 11240.

5. The one-bath dyeing and depilatory finishing process for hemp-cotton knitted fabric according to claim 1, characterized in that: In the step (4), the neutral cellulase is any one of the neutral cellulase EVCLEAN MS, neutral deoxidizing polishing enzyme TF161LC, cellulase Neupolish 8000L, and neutral etching agent QTQ-102.

6. The one-bath dyeing and depilatory finishing process for hemp-cotton knitted fabric according to claim 1, characterized in that: After step (7) is completed, the grey cloth is pre-shrunk. Under the action of steam in the pre-shrunk machine, the linen-cotton knitted fabric runs without tension, so that the stress inside the fabric is fully released and the shrinkage rate of the fabric is improved.

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