Lyocell cross-linked fiber and production method thereof

Abstract

The invention discloses a lyocell cross-linked fiber and a production method thereof, and the production method comprises the following steps: dipping lyocell fiber in a treating fluid containing a treating agent active substance and an acid catalyst, and carrying out padding, drying and curing treatment to obtain the lyocell cross-linked fiber with high oxidation reduction resistance, the acidic catalyst is a Lewis acid substance; the treating agent active substance is a compound shown as a formula A and / or a compound shown as a formula B; wherein R is one or more of hydrogen, methoxyl and ethyoxyl; and n is 1, 2 or 3. The lyocell cross-linked fiber prepared by the method disclosed by the invention has good tolerance to application scenes such as oxidation and reduction, and can meet the requirements of process environments such as dyeing and finishing pretreatment, dyeing, stripping, post-washing and the like of natural cellulose blended fabrics. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of fiber materials, and in particular relates to a lyocell cross-linked fiber and a production method thereof. Background Art

[0002] As a regenerated cellulose fiber, lyocell fiber has high strength and good comfort for clothing, and it also has unique fibrillation characteristics. As people's requirements for fiber material performance continue to increase, improving the redox tolerance of lyocell cross-linked fibers has become a research focus.

[0003] The existing lyocell cross-linked fibers on the market have a certain ability to resist fibrillation. For example, the traditional cross-linking method for lyocell cross-linked fibers to resist fibrillation is as follows: US005779737A patent document discloses that 1,3,5-triacrylamide hexahydro-1,3,5 triazine is preferred as a cross-linking agent, and lyocell cross-linked fibers are obtained through a certain process of cross-linking; the related patent document with application number 98801507.2 prefers 2,4-dichloro-6-hydroxytriazine sodium salt as a cross-linking agent, and lyocell fibers are cross-linked through a certain process. Although these methods have given lyocell fibers some ability to resist fibrillation to a certain extent, in complex downstream application scenarios, especially under complex redox conditions such as pre-dyeing and finishing treatment, dyeing, stripping, and post-washing, the cross-linking effect will be quickly destroyed and the original ability to resist fibrillation will be lost. Summary of the invention

[0004] In view of this, the present invention provides a lyocell cross-linked fiber with high resistance to oxidation and reduction and a production method thereof. The lyocell cross-linked fiber prepared by the method of the present invention has good tolerance to application scenarios such as oxidation and reduction, and can meet the requirements of the process environment such as pre-dyeing and finishing treatment, dyeing, stripping, and post-washing of natural cellulose blended fabrics.

[0005] The present invention provides a method for producing lyocell cross-linked fibers, comprising the following steps:

[0006] The lyocell fiber is immersed in a treatment solution containing a treatment agent active substance and an acid catalyst, and subjected to padding, drying and preferably curing treatment in the range of 140-160° C. to obtain a lyocell cross-linked fiber with high oxidation-reduction resistance; the acid catalyst is a Lewis acid substance; and the concentration of the treatment agent active substance in the treatment solution is preferably 5-15wt%;

[0007] The active substance of the treatment agent is a compound having a structure of formula A and / or a compound having a structure of formula B; in formula A, R is one or more of hydrogen, methoxy and ethoxy; in formula B, n is 1, 2 or 3;

[0008]

[0009] In order to meet the needs of downstream different application scenarios for lyocell fiber processing, etc., the present invention provides a method for producing lyocell cross-linked fibers, which is a method for improving the redox tolerance of lyocell cross-linked fibers, including a formula of anti-fibrillation cross-linking liquid for lyocell fibers resistant to redox use environments and a method for anti-fibrillation treatment.

[0010] See also Figure 1 , Figure 1 A schematic diagram of the process flow of the production method provided in an embodiment of the present invention. The embodiment of the present invention first configures a treatment liquid, wherein the treatment liquid comprises a treatment agent active substance and an acidic catalyst. Wherein, the treatment agent active substance is a mixture of one or more compounds shown in formula A and formula B, wherein R in formula A is connected to carbon C, R = hydrogen (H), methoxy (-OCH3), ethoxy (-OCH2CH3), when R is H, the structure of the treatment agent active substance is as follows. In formula B, n = 1, 2, 3, preferably n is 1 or 2;

[0011]

[0012] In the embodiment of the present invention, the active substance of the treatment agent can cross-link with cellulose molecules under certain conditions, and is also called a cross-linking agent; commercially available substances can be used. In addition, the concentration of the active substance of the treatment agent in the treatment solution is 5-15wt%, preferably 8-12wt%; if the concentration is too low, it is difficult to achieve a good cross-linking effect.

[0013] The acidic catalyst described in the embodiment of the present invention is a Lewis acid substance (a substance having an empty orbital for accepting electron pairs), preferably one or more of aluminum chloride, ferric chloride, magnesium chloride and acetic acid, and further magnesium chloride and / or acetic acid; the concentration of the acidic catalyst in the treatment liquid is preferably 2-3wt%, and the balance of the treatment liquid is water.

[0014] In the embodiment of the present invention, the lyocell fiber is immersed in the above-mentioned treatment solution, and is padded 1-3 times at room temperature, or multiple padding treatments are also performed, and the padding rate each time is 120-150% by mass. The present invention has no special restrictions on the specifications of the lyocell fiber, and the lyocell fiber commonly used in the art can be used; the room temperature padding is a temperature range well known to those skilled in the art.

[0015] In the embodiment of the present invention, the lyocell fiber after padding is preferably dried at a temperature of preferably 100-130°C, more preferably 110-125°C, until the fiber dryness is greater than 95%. In the embodiment of the present invention, the lyocell fiber after drying is cured at a relatively high temperature, at a curing temperature of 140-160°C, preferably controlled within the range of 140-155°C, and the curing time can be 3-10 minutes, preferably 4-10 minutes.

[0016] In the embodiment of the present invention, the cured fiber can be subjected to conventional water washing, oiling and drying treatments in sequence to obtain a lyocell cross-linked fiber product, which has good anti-fibrillation ability and acid and alkali fastness. After curing, the treatment preferably specifically includes: washing the fiber at least 4 times, washing until the pH is neutral, oiling at 50-60°C, the oil content is controlled between 0.28% and 0.33%, and the drying temperature is controlled between 65-95°C until the moisture regain reaches 8-13%.

[0017] Accordingly, an embodiment of the present invention provides a highly oxidative-reduction resistant Lyocell cross-linked fiber obtained by the production method as described above.

[0018] The Lyocell cross-linked fiber described in some embodiments of the present invention still has a certain cross-linking effect after being acted on by an oxidant such as hydrogen peroxide at a pH value of 8-11, and can also withstand the application environment of reduction dyeing. In other specific embodiments, the Lyocell cross-linked fiber is also dyed with reactive dyes, and there is no special restriction on the dyes and dyeing process. Depending on the application scenario dyes and process conditions, the dyeing and testing of different manufacturers are slightly different.

[0019] The embodiment of the present invention mainly shows the anti-fibrillation performance of Lyocell cross-linked fiber through wet wear value. The test method of wet wear value (WAV) is: using Lenzing instruments VIBROSKOP 500 fineness meter and DELTA 100 wet wear meter, and simultaneously testing the nominal linear density D and wet wear circle number N of 20 tested fibers. The larger the wet wear value, the stronger the anti-fibrillation ability of the fiber. The WAV calculation formula is shown as follows:

[0020]

[0021] Compared with the prior art, one of the purposes of the present invention is to effectively improve the redox tolerance of the produced lyocell cross-linked fiber by adding specific active substances of the treatment agent and acid catalysts in the treatment liquid and combining with a specific treatment process, so as to meet the requirements of the process environment such as pre-dyeing and finishing treatment, dyeing, stripping, and post-washing of natural cellulose blended fabrics such as cotton and linen. In addition, the method is simple to operate, low in cost, and suitable for large-scale production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of a process flow of a production method provided by an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the dyeing process curve of Example 8 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Unless otherwise defined, all professional terms used hereinafter have the same meaning as those skilled in the art generally understand. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0026] The technical solutions in the implementation cases of this application will be described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of invention protection. In the following examples, all raw materials are commercially available.

[0027] Example 1

[0028] An embodiment of the present invention comprises the following steps:

[0029] Step 1: Prepare a treatment solution with a treatment agent active substance concentration of 9 wt%. Use crosslinking agent A (R = -OCH3, the specific structure is shown below),

[0030]

[0031] The solution was added into solvent water, and then the pH value of the solution was adjusted to 4.5 with acetic acid to obtain a treated solution.

[0032] Step 2: Padding. The lyocell fiber is immersed in the treatment solution and subjected to padding treatment, with the padding rate of each time being 120%; this step is repeated 3 times. The parameters of the uncrosslinked lyocell fiber are fineness 1.33 dtex, strength 4.2-4.6 cN / dtex, and wet abrasion value 85-110 turns.

[0033] Step 3: Drying: The impregnated lyocell fibers are dried at a temperature of 110° C. until the fiber dryness is greater than 95%.

[0034] Step 4: Curing: The dried lyocell fiber is cured, and the curing temperature is controlled at 140°C and the curing time is 6 minutes.

[0035] Step 5: washing, oiling, and drying. The cured fiber is subjected to multiple washing and drying treatments, specifically including: washing the fiber at least 4 times, washing until the pH is neutral, oiling at 50-60°C, the oil content is controlled between 0.28% and 0.33%, the drying temperature is controlled between 65-95°C, and the moisture regain reaches 8-13% (the same as in the following embodiments), to obtain the final lyocell cross-linked fiber product 1 (abbreviated as product 1), and its wet wear value is shown in the following table.

[0036] It can be seen from Table 1 that this method can achieve a cross-linking effect far superior to that of competing products on the market. In Table 1, competing product 1 is prepared according to the relevant invention patent US005779737A, and competing product 2 is prepared according to the relevant invention patent CN98801507.2, and the following examples are the same.

[0037] Table 1. Anti-fibrillation effect of Lyocell cross-linked fiber product 1

[0038] product Wet wear value, number of turns / dtex Product 1 920 Competitor 1 260 Competitor 2 410

[0039] Example 2

[0040] An embodiment of the present invention comprises the following steps:

[0041] Step 1: Prepare a treatment solution with a treatment agent active substance concentration of 11 wt%. Use crosslinking agent A (R = -OCH2CH3, the specific structure is shown below),

[0042]

[0043] This was added into water, and then 3 wt % of magnesium chloride was added into the solution to obtain a treated solution.

[0044] Step 2: Padding: The lyocell fiber is immersed in the treatment solution and subjected to padding treatment, with the padding rate each time being 140%; this step is repeated twice.

[0045] Step 3: Drying: The impregnated lyocell fibers are dried at a temperature of 120° C. until the fiber dryness is greater than 95%.

[0046] Step 4: Curing: The dried lyocell fiber is cured, and the curing temperature is controlled at 143°C and the curing time is 7 minutes.

[0047] Step 5: washing, oiling, and drying. The cured fiber is washed and dried multiple times to obtain the final lyocell cross-linked fiber product 2. The obtained fiber product is recorded as product 2, and its wet wear value is shown in the table below. It can be seen from Table 2 that compared with competing products, the method product provided by the present invention still has a cross-linking advantage over competing products.

[0048] Table 2. Anti-fibrosis effect of product 2

[0049] product Wet wear value, number of turns / dtex Product 1 920 Product 2 730 Competitor 1 260 Competitor 2 410

[0050] Example 3

[0051] An embodiment of the present invention comprises the following steps:

[0052] Step 1: Prepare a treatment solution with a treatment agent active substance concentration of 9.5 wt%. Use crosslinking agent A (the specific structure is shown below),

[0053]

[0054] This was added to water, and then 2.7 wt % of magnesium chloride was added to the solution to obtain a treated solution.

[0055] Step 2: Padding: The lyocell fiber is immersed in the treatment solution and subjected to padding treatment, with the padding rate each time being 125%; this step is repeated 3 times.

[0056] Step 3: Drying: The impregnated lyocell fibers are dried at a temperature of 120° C. until the fiber dryness is greater than 95%.

[0057] Step 4: Curing: The dried lyocell fiber is cured, and the curing temperature is controlled at 151°C and the curing time is 8 minutes.

[0058] Step 5: washing, oiling, and drying. The cured fiber is washed and dried multiple times to obtain the final lyocell cross-linked fiber product 3, which is denoted as product 3. The wet wear value thereof is shown in the table below. As can be seen from Table 3, compared with competing products, the method product provided by the present invention still has a cross-linking advantage over competing products.

[0059] Table 3. Anti-fibrosis effect of product 3

[0060] product Wet wear value, number of turns / dtex Product 1 920 Product 2 730 Product 3 691 Competitor 1 260 Competitor 2 410

[0061] Example 4

[0062] An embodiment of the present invention comprises the following steps:

[0063] Step 1: Prepare a treatment solution with a treatment agent active substance concentration of 8.5 wt%. Use cross-linking agent B (n=1), whose structure is as follows:

[0064]

[0065] This was added to water, and then 2.3 wt% magnesium chloride was added to the solution to obtain a treated solution.

[0066] Step 2: Padding: The lyocell fiber is immersed in the treatment solution and subjected to padding treatment, with the padding rate each time being 130%; this step is repeated twice.

[0067] Step 3: Drying: The impregnated lyocell fibers are dried at a temperature of 110° C. until the fiber dryness is greater than 95%.

[0068] Step 4: Curing: The dried lyocell fiber is cured, and the curing temperature is controlled at 153°C and the curing time is 9 minutes.

[0069] Step 5: washing, oiling, and drying. The cured fiber is washed and dried several times to obtain the final lyocell cross-linked fiber product 4, which is denoted as product 4. Its wet wear value is shown in the table below.

[0070] Table 4. Anti-fibrosis effects of different products

[0071] product Wet wear value, number of turns / dtex Product 4 739 Competitor 1 260 Competitor 2 410

[0072] It can be seen from Table 4 that compared with competing products, the method product provided by the present invention makes the number of wet abrasion value of Lyocell cross-linked fiber higher.

[0073] Example 5

[0074] An embodiment of the present invention comprises the following steps:

[0075] Step 1: Prepare a treatment solution with a treatment agent active substance concentration of 9.3 wt%. Use cross-linking agent B (n=2), whose structure is as follows:

[0076]

[0077] This was added to water, and then 2.2 wt% magnesium chloride was added to the solution to obtain a treated solution.

[0078] Step 2: Padding. The lyocell fiber is immersed in the treatment solution and subjected to padding treatment, with the padding rate each time being 125%; this step is repeated twice.

[0079] Step 3: Drying: The impregnated lyocell fibers are dried at a temperature of 115° C. until the fiber dryness is greater than 95%.

[0080] Step 4: Curing: The dried lyocell fiber is cured, and the curing temperature is controlled at 155°C and the curing time is 9.5 minutes.

[0081] Step 5: washing, oiling, and drying. The cured fiber is washed and dried multiple times to obtain the final lyocell cross-linked fiber product 5.

[0082] The obtained fiber product is recorded as product 5, and its wet abrasion value is shown in the following table. As can be seen from Table 5, compared with the competing products, the method product provided by the present invention makes the Lyocell cross-linked fiber have a higher wet abrasion value.

[0083] Table 5. Anti-fibrillation effect of product 5

[0084] product Wet wear value, number of turns / dtex Product 5 789 Competitor 1 260 Competitor 2 410

[0085] Example 6

[0086] Products 1, 2 and competitor products 1, 2 were treated in an oxidative environment to observe the decrease in wet wear values ​​of different cross-linked fibers in different oxidative environments.

[0087] Treatment method 1: The treatment solution contains 50g / L caustic soda, 20g / L hydrogen peroxide, and 15g / L oxygen bleaching stabilizer (specific model is Taiyang Textile Oxygen Bleaching Stabilizer TY-YR013); stacking at 40℃ for 24 hours - washing and drying;

[0088] Treatment method 2 is 75℃ hot boiling oxygen bleaching process: caustic soda 10g / L, hydrogen peroxide 10g / L, oxygen bleaching stabilizer TY-YR0135g / L, 75℃ treatment for 45 minutes, water washing and drying;

[0089] Treatment method 3 is 100℃ hot boiling oxygen bleaching process: caustic soda 10g / L, hydrogen peroxide 10g / L, oxygen bleaching stabilizer TY-YR0135g / L, 100℃ treatment for 45 minutes, water washing and drying;

[0090] Treatment method 4 is to test the stability of chlorine bleaching: (sodium hypochlorite) effective chlorine 5g / L, 3g / L, adjust pH to 10.5, pad at room temperature (19.8℃), wet stack for 45 minutes - wash and dry;

[0091] Table 6 shows the decline in fiber cross-linking effect in an oxidative environment. It can be seen that products 1 and 2 have good antioxidant capacity, while competing products almost lose their cross-linking effect in an oxidative environment.

[0092] Table 6. Oxidation resistance of different products

[0093] product Solution 1 Solution 2 Solution 3 Solution 4 Product 1 32.56％ 19.37％ 31.25％ 21.62％ Product 2 38.66％ 23.19％ 36.04％ 27.20％ Competitor 1 74.86％ 67.85％ 78.03％ 90.10％ Competitor 2 91.03％ 67.87％ 87.53％ 39.50％

[0094] Note: The decline in cross-linking effect is expressed by the cross-linking agent decline rate (wet wear value decline rate), cross-linking agent decline rate = (wet wear value before treatment - wet wear value after treatment - initial wet wear value (85 cycles)) / (wet wear value before treatment - initial wet wear value (85 cycles).

[0095] Example 7

[0096] Products 4, 5 and competitor products 1, 2 were treated in a reducing environment to observe the decrease in wet abrasion values ​​of different cross-linked fibers in the reducing environment.

[0097] Reduction dyeing environment: sodium hydroxide 40g / L, hydrosulfite 40g / L, 98℃ for one hour.

[0098] Table 7 shows the decline in fiber cross-linking effect in a reducing environment. It can be seen that the reduction resistance of products 3 and 4 is far superior to other products.

[0099] Table 7. Reduction resistance of different products

[0100] product Wet wear value reduction rate Product 4 32.70％ Product 5 40.21％ Competitor 1 98.32％ Competitor 2 99.45％

[0101] Example 8

[0102] Products 4, 5 and competitor products 1, 2 were dyed. The dyeing process was as follows to observe the dyeing performance of different cross-linked fibers. The dyeing process formula is as follows:

[0103] Sodium sulfate 50g / L;

[0104] Sodium carbonate 10g / L;

[0105] Sodium bicarbonate 5g / L;

[0106] Reactive Blue 1.6% owf (0.08% wt).

[0107] Dyeing process curve see Figure 2 The dye bath was heated from room temperature to 80°C and then immersed in the fiber. Sodium sulfate, sodium carbonate and sodium bicarbonate were added for active dyeing. The temperature was then lowered to 50°C for washing. The dyed fiber samples were subjected to conventional performance tests, and the results were as follows:

[0108] Table 8. Sample staining LAB values

[0109] Sample Type L* a* b* c h Product 4 65.94 -10.00 -29.48 31.13 71.26 Product 5 64.98 -10.06 -30.73 32.34 71.88 Ordinary silk 62.20 -8.24 -33.13 34.14 76.03 Competitor 1 73.25 -8.46 -24.56 25.98 70.99 Competitor 2 54.96 -6.19 -38.25 38.74 80.81

[0110] Table 9. Sample dye uptake

[0111] Sample Type Product 4 Product 5 Ordinary silk Competitor 1 Competitor 2 Dyeing rate 47.04％ 47.75％ 48.32％ 43.30％ 52.21％

[0112] It can be seen that compared with competitors 1 and 2, the dyeing rate and color development of products 4 and 5 are closer to those of ordinary lyocell fibers, and the fiber dyeing by this cross-linking treatment method meets the product dyeing requirements.

[0113] It can be seen from the above examples that the Lyocell cross-linked fiber product prepared by the method of the present invention has good tolerance to application scenarios such as oxidation and reduction, and can meet the requirements of the process environment such as pre-dyeing and finishing treatment, dyeing, stripping, and post-washing of natural cellulose blended fabrics. In addition, the method is simple to operate, low in cost, and suitable for large-scale production applications.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing lyocell cross-linked fibers, characterized in that: The following steps are involved: The lyocell fiber is immersed in a treatment solution containing a treatment agent active substance and an acid catalyst, and is subjected to padding, drying and curing treatment to obtain a lyocell cross-linked fiber with high oxidation-reduction resistance; The acidic catalyst is a Lewis acid substance; The active substance of the treatment agent is a compound having a structure of formula A and / or a compound having a structure of formula B; in formula A, R is one or more of hydrogen, methoxy and ethoxy; in formula B, n is 1, 2 or 3; 2. The production method according to claim 1, characterized in that The curing temperature is in the range of 140-160°C.

3. The production method according to claim 1, characterized in that The concentration of the active substance of the treatment agent in the treatment liquid is 5-15wt%.

4. The production method according to claim 1, characterized in that The acidic catalyst is one or more of aluminum chloride, ferric chloride, magnesium chloride and acetic acid.

5. The production method according to claim 4, characterized in that: The concentration of the acid catalyst in the treatment liquid is 2-3 wt %.

6. The production method according to any one of claims 1 to 5, characterized in that: The number of times of the dipping and rolling is 1-3 times, and the rolling rate of each time is 120-150%.

7. The production method according to any one of claims 1 to 5, characterized in that: The drying is carried out at 100-130° C. to dry the fiber to a degree of dryness greater than 95%.

8. The production method according to claim 7, characterized in that: The curing treatment lasts for 3-10 minutes; after that, washing, oiling and drying are performed to obtain a lyocell cross-linked fiber product.

9. Lyocell cross-linked fiber with high oxidation-reduction resistance obtained by the production method according to any one of claims 1 to 8.

10. The Lyocell cross-linked fiber according to claim 9, characterized in that: The lyocell cross-linked fibers are also dyed with reactive dyes.

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