A method for preparing recycled cotton viscose fiber

Abstract

The application discloses a preparation method of recycled cotton viscose fiber and belongs to the technical field of waste recycling. The preparation method comprises the following processes: obtaining spinning viscose by mixing pulp, impregnating, squeezing, aging, yellowing, dissolving, ripening and defoaming of recycled cotton pulp; and obtaining recycled cotton viscose fiber by spinning, refining and drying of the spinning viscose. The application aims to realize the recycling of recycled cotton pulp formed by discarded cotton clothes or floor cotton of textile mills, to prepare spinning viscose and then prepare cotton viscose fiber, and to obtain pure cotton products with excellent quality, which can be used in the textile industry, so as to realize environmental protection, regeneration and recycling in the textile industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste recycling, and particularly relates to a preparation method of recycled cotton viscose fiber. BACKGROUND

[0002] At present, most of the waste cotton materials can only be treated by landfill, incineration for power generation, or even simple incineration. The disadvantage of the landfill method is that it occupies a large area and is easy to cause secondary pollution. The incineration method not only has high investment cost and low resource utilization rate, but also causes serious air pollution. Therefore, how to realize the recycling of waste cotton materials is a technical problem that needs to be solved at the present stage.

[0003] The patent with the publication number CN102660791 discloses a method for recycling old clothes. Old cotton clothes are used as raw materials to produce cotton pulp, which is treated with caustic soda and carbon disulfide to obtain orange-yellow cellulose sodium xanthate. The cellulose sodium xanthate is then dissolved in a dilute sodium hydroxide solution to become viscose. The viscose is filtered, aged, and placed at 38 degrees for 20 hours. After defoaming, wet spinning is performed. The coagulation liquid is composed of sulfuric acid, sodium sulfate, and zinc sulfate. The cellulose sodium xanthate in the viscose reacts with sulfuric acid in the coagulation liquid to decompose, and the regenerated cellulose is precipitated. The obtained cellulose fiber is washed with water, desulfurized, bleached, and dried to become viscose fiber. However, the recycling method used in this patent has technical problems such as rough production process, poor product performance, and inability to be practically applied. SUMMARY

[0004] The present application aims to provide a preparation method of recycled cotton viscose fiber with an environmentally friendly process and high product quality.

[0005] The technical scheme of the present application is as follows: the preparation method of recycled cotton viscose fiber comprises the following processes: recycling cotton pulp is mixed, impregnated, pressed, aged, yellowed, dissolved, matured, and defoamed to obtain spinning viscose. The spinning viscose is then spun, refined, and dried to obtain recycled cotton viscose fiber.

[0006] Further, the raw material of the recycled cotton pulp is discarded cotton clothing or floor cotton from textile mills.

[0007] Further, the composition of the recycled cotton pulp is as follows: methyl cellulose 94±1%, moisture 9.0±1%, ash content 0.08±0.002%, viscosity 9.0±1mpa.s, whiteness 93±1%, iron <10ppm, polyglucose <3.8%, resin <0.2%, and CS2(10ml) reaction performance <11.5S.

[0008] Further, the degree of polymerization of the recycled cotton pulp is 450-500mpa.s.

[0009] Further, the parameters of the impregnation process are: the concentration of the impregnation lye is 228±2g / L, the temperature of the impregnation lye is 55±0.5℃; the impregnation lye is prepared by using concentrated lye and desalted water, and the press lye is not used.

[0010] Further, the composition of the alkali cellulose after the pressing process is: the methyl cellulose content is 34±0.5%, and the alkali content is 15.0±1%.

[0011] Further, the addition amount of the yellowing CS2 in the yellowing process is: 1025 / 10000KG / P; and the concentration of the yellowing dissolving lye is 18-20g / I.

[0012] Further, the parameters of the spinning viscose are: the viscosity is 28-33S, the methyl cellulose is 9.0-9.2%, the alkali content is 4.75-4.85%, and the ripening degree is 11-14ml calculated by 10% ammonium chloride.

[0013] Further, the parameters of the refining process are: the concentration of sulfuric acid is 110-112g / L, the concentration of zinc sulfate is 9.5-10.5g / L, the specific gravity is 1.310-1.330, the acid temperature is 48.5-49.5℃, the spinning two-bath temperature is 82±2℃, the sulfuric acid content is 30-40g / L, the drawing rate is 95±10%, the refining desulfurization temperature is 80±2℃, the concentration of sodium hydroxide is 1.0-1.4g / L, the concentration of bleaching agent sodium hypochlorite is 0.1-0.3g / L, the oil bath temperature is 65±5℃, and the concentration of oil agent is 9±1g / L.

[0014] Further, the product index data of the recycled cotton viscose fiber are: the dry breaking strength is ≥2.30CN / dtex, the wet breaking strength is ≥1.10CN / dtex, the oil content is 0.30±0.05%, the residual sulfur content is ≤8.0mg / 100g, the whiteness is 83.0±1.5%, and the defect is ≤4.0mg / 100g.

[0015] Inventive principle: In the existing viscose fiber production, whether in theory or in production practice, the pulp polymerization degree used for viscose manufacturing is above 500mpa.s, and the pulp with a polymerization degree below 500mpa.s is difficult to produce, and the finished product quality is difficult to meet the requirements of textile use. However, in the present application, the recycled cotton pulp made from pure cotton waste has a lower polymerization degree of 450-500mpa.s, which is difficult to produce. Therefore, in order to facilitate production and manufacturing, the present application adopts one-time impregnation and pressing, and designs a suitable spinning viscose control process and refining process to ensure that the product performance of the recycled cotton viscose fiber meets the use requirements.

[0016] Beneficial effects: Compared with the prior art, the present application has the following remarkable advantages:

[0017] (1) The application prepares the recycled cotton pulp formed by the waste and old discarded human cotton clothes or the cotton dropped by the textile mill into the spinning viscose and then the cotton viscose fiber, the obtained pure cotton product has excellent quality and can be used in the textile industry to achieve the environmental protection, regeneration and recycling of the textile industry;

[0018] (2) According to the low polymerization characteristics of the recycled cotton pulp, the design of the processes such as impregnation, pressing, yellowing and refining is combined to improve the product performance of the recycled cotton fiber, and the environmental protection of the process is ensured. DETAILED DESCRIPTION

[0019] Next, the application will be further described in combination with specific embodiments.

[0020] Embodiment 1: The preparation method of the recycled cotton viscose fiber provided by the application comprises the following processes:

[0021] The recycled cotton pulp is obtained through mixing, impregnation, pressing, aging, yellowing, dissolution, ripening and defoaming; the spinning viscose is obtained through spinning, refining and drying.

[0022] The quality composition of the recycled cotton pulp is: methyl cellulose 93.2%, moisture 9.89%, ash content 0.082%, viscosity 9.15 mpa.s, whiteness 93.5%, iron 9.88 ppm, polyvalent sugar 3.80%, resin 0.17%, and CS2 (10 ml) reaction performance <10.8 S;

[0023] The parameters of the impregnation process are as follows: the impregnation alkali solution is prepared by using concentrated alkali and desalted water, and the liquid alkali is not used; the impregnation alkali concentration is 226 g / L, and the impregnation alkali temperature is 56℃.

[0024] The composition of the alkali cellulose after pressing is: methyl cellulose content is 34.5%, and alkali content is 15.3%.

[0025] The CS2 addition amount in the yellowing process is 1025 L / 10000 KG / P; the yellowing dissolution alkali concentration is 19.5 g / I.

[0026] The process parameters of the spinning viscose are: viscosity 32 S, methyl cellulose 9.15%, alkali content 4.79%, and ripening degree 11.5 ml calculated by 10% ammonium chloride.

[0027] The parameters of the refining process are: the spinning acid bath composition includes sulfuric acid 112 g / L and zinc sulfate 9.8 g / L, the specific gravity is 1.318, the acid temperature is 48.7℃, the spinning two bath temperature is 83.5℃, the sulfuric acid content is 35.8 g / L, the draft rate is 98.5%, the refining desulfurization temperature is 83℃, the sodium hydroxide concentration is 1.2 g / L, the bleaching agent sodium hypochlorite concentration is 0.25 g / L, the oil bath temperature is 64.8℃, and the oil agent concentration is 9.5 g / L.

[0028] The drying process is three-stage drying process: the temperature of the front zone is 138℃, the temperature of the middle zone is 138℃, and the temperature of the rear zone is 79℃.

[0029] The product index data of the prepared cotton viscose fiber are: dry breaking strength 2.32 CN / dtex, wet breaking strength 1.13 CN / dtex, oil content 0.32%, residual sulfur content 6.8 mg / 100 g, whiteness 83.5%, and defect 2.5 mg / 100 g;

[0030] The whole production process is smooth, and the product quality completely meets the standards.

[0031] The preparation method of the recycled cotton viscose fiber provided by the application comprises the following processes:

[0032] The recycled cotton pulp is mixed, immersed, pressed, aged, yellowed, dissolved, matured, and defoamed to obtain spinning viscose; and the spinning viscose is spun, refined, and dried to obtain the recycled cotton viscose fiber.

[0033] The mass composition of the recycled cotton pulp is: methyl cellulose 94.1%, moisture 9.65%, ash content 0.083%, viscosity 9.32 mpa.s, whiteness 93.5%, iron 9.88 ppm, polyvalent sugar 3.75%, resin 0.19%, and CS2 (10 ml) reaction performance 10.9 S;

[0034] The parameters of the immersion process are: the immersion alkali solution is prepared by using concentrated alkali and desalted water, and the pressurized alkali is not used; the immersion alkali concentration is 226 g / L, and the immersion alkali temperature is 53℃.

[0035] The composition of the alkali cellulose after pressing is: methyl cellulose content 34.1%, and alkali content 15.3%.

[0036] The yellowing CS2 addition amount in the yellowing process is 1025 L / 10000 KG / P; and the yellowing and dissolving alkali concentration is 20 g / L.

[0037] The process parameters of the spinning viscose are: viscosity 30 s, methyl cellulose content 9.12%, alkali content 44.85%, and maturity degree 13 ml calculated by 10% ammonium chloride.

[0038] The parameters of the refining process are: the spinning acid bath includes sulfuric acid 112 g / L and zinc sulfate 10.1 g / L, the specific gravity is 1.335, and the acid temperature is 49.5℃; the temperature of the spinning two-bath is 83℃, the sulfuric acid content is 45 g / L, and the drawing rate is 98%; the post-processing desulfurization temperature is 81℃, the sodium hydroxide concentration is 1.5 g / L, the bleaching agent sodium hypochlorite concentration is 0.3 g / L; the oil bath temperature is 63℃, and the oil agent concentration is 9 g / L.

[0039] The drying process is three-stage drying process: the temperature of the front zone is 136℃, the temperature of the middle zone is 137℃, and the temperature of the rear zone is 58℃.

[0040] The dry breaking strength of the cotton viscose fiber prepared is 2.31 CN / dtex, the wet breaking strength is 1.15 CN / dtex, the oil content is 0.30%, the residual sulfur content is 6.8 mg / 100 g, the whiteness is 83.5%, and the defect is 3.2 mg / 100 g;

[0041] The whole production process is smooth, and the product quality completely meets the standards.

[0042] Comparative Example 1: Different from Example 1 is that the concentration of the dipping alkali is 222-224 g / L.

[0043] It is found during the experiment that the viscose manufacturing quality deviation is difficult to filter.

[0044] Comparative Example 2: Different from Example 1 is that the dipping alkali temperature is 51-53℃.

[0045] It is found during the experiment that the dipping effect is poor, and the production is difficult.

[0046] Comparative Example 3: Different from Example 1 is that the amount of yellowing CS2 added is 980-1000 L / 8000 KG / P.

[0047] It is found during the experiment that the viscose manufacturing quality deviation is difficult to filter, and the production is difficult.

[0048] Comparative Example 4: Different from Example 1 is that the process parameters of the spinning viscose are: viscosity 35-40 S, methyl 8.8-9.0%, alkali content 4.75-4.85% outside the range, and aging degree 11-14 ml outside the range calculated by 10% ammonium chloride.

[0049] It is found during the experiment that the spinning forming production is difficult.

[0050] Comparative Example 5: Different from Example 1 is that the parameters of the refining process are not within the scope of the application.

[0051] It is found during the experiment that the finished product quality does not meet the standards.

Claims

1. A method for preparing recycled cotton viscose fiber, characterized in that, The process includes the following steps: recycled cotton pulp is mixed, impregnated, pressed, aged, xanthated, dissolved, matured, and defoamed to obtain spun viscose; the spun viscose is then spun, refined, and dried to obtain recycled cotton viscose fiber; the degree of polymerization of the recycled cotton pulp is 450-500 mPa·s; the parameters of the impregnation process are: the concentration of the impregnation alkali solution is 228±2 g / L, and the temperature of the impregnation alkali solution is 55±0.5℃; the amount of xanthating CS2 added in the xanthation process is 1025 L / 10000 KG / P, and the concentration of xanthating dissolving alkali is 18-20 g / L; the parameters of the spun viscose are: viscosity 28-33 S, methyl cellulose 9.0-9.2%. The alkali content is 4.75-4.85%, and the maturity is 11-14 ml based on 10% ammonium chloride. The parameters of the refining process are as follows: the spinning acid bath includes sulfuric acid concentration of 110-112 g / L and zinc sulfate concentration of 9.5-10.5 g / L, specific gravity of 1.310-1.330, acid temperature of 48.5-49.5℃, spinning second bath temperature of 82±2℃, sulfuric acid content of 30-40 g / L, draw ratio of 95±10%, refining desulfurization temperature of 80±2℃, sodium hydroxide concentration of 1.0-1.4 g / L, bleaching agent sodium hypochlorite concentration of 0.1-0.3 g / L, oil bath temperature of 65±5℃, and oil concentration of 9±1 g / L.

2. The method for preparing recycled cotton viscose fiber according to claim 1, characterized in that, The raw material for the recycled cotton pulp is discarded rayon clothing or cotton scraps left over from textile factories.

3. The method for preparing recycled cotton viscose fiber according to claim 1, characterized in that, The composition of the recycled cotton pulp is as follows: cellulose 94±1%, moisture 9.0±1%, ash 0.08±0.002%, viscosity 9.0±1 mpa.s, whiteness 93±1%, iron <10 ppm, pentosans <3.8%, resin <0.2%, and reaction performance of <11.5 s per 10 ml CS2.

4. The method for preparing recycled cotton viscose fiber according to claim 1, characterized in that, The composition of alkali cellulose after the pressing process is: methyl cellulose content of 34±0.5% and alkali content of 15.0±1%.

5. The method for preparing recycled cotton viscose fiber according to claim 1, characterized in that, The product specifications of the recycled cotton viscose fiber are as follows: dry breaking strength ≥ 2.30 CN / dtex, wet breaking strength ≥ 1.10 CN / dtex, oil content 0.30±0.05%, residual sulfur content ≤ 8.0 mg / 100g, whiteness 83.0±1.5%, and defects ≤ 4.0 mg / 100g.