Production method of Lyocell fiber

Abstract

The invention belongs to the field of chemical fibers, and particularly relates to a Lyocell fiber production method which comprises the following steps: a) a Lyocell fiber spinning glue solution enters a spinning machine table after passing through a filter, and silk is discharged through a spinneret plate; b) enabling tows discharged from the spinneret plate to enter a spinning bath for curing and forming to obtain Lyocell fibers; a wind field is arranged between the spinneret plate and the spinning bath, and the wind direction of the wind field is parallel to the spinneret plate; the yarn outlet temperature of the spinneret plate and the temperature, humidity and wind speed of the wind field meet the following requirements: H = [(2T1-100) * T2 / 100] * [(T2-10) / 10 * (W / 100) + V / h], and H is more than or equal to 4.5 and less than or equal to 10. According to the production method provided by the invention, a plurality of process parameters in the production process of the Lyocell fibers are comprehensively adjusted, so that the product defects of the 0.9-1.1 dtex Lyocell fibers are obviously reduced.

Description

Technical Field

[0001] The invention belongs to the field of chemical fibers, and in particular relates to a production method of Lyocell fibers. Background Art

[0002] At present, the products of Lyocell fiber manufacturers are mainly 1.33dtex. The quality of Lyocell fibers of other specifications is unstable due to poor matching of production processes. Especially when the fiber fineness drops below 1.1dtex, there are common problems such as many broken ends and high product defects, which affect product quality and even prevent normal production. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a method for producing Lyocell fibers, which is suitable for the production of 0.9-1.1 dtex Lyocell fibers and has low product defects.

[0004] The present invention provides a method for producing Lyocell fiber, comprising the following steps:

[0005] a) Lyocell fiber spinning solution passes through the filter and enters the spinning machine, where it is filamented through the spinneret;

[0006] b) the filament bundles from the spinneret enter the spinning bath and are solidified and formed to obtain Lyocell fibers;

[0007] The Lyocell fiber spinning solution has a zero shear viscosity of ≥6000 Pa·s at 85° C. and a methyl cellulose content of ≤12wt%;

[0008] The distance between the spinneret and the spinning bath is 10 to 50 mm;

[0009] A wind field is arranged between the spinneret and the spinning bath, and the wind direction of the wind field is parallel to the spinneret;

[0010] The outlet temperature of the spinneret meets the following requirements with the temperature, humidity and wind speed of the wind field:

[0011] H=[(2T1-100)×T2 / 100]×[(T2-10) / 10×(W / 100)+V / h], 4.5≤H≤10;

[0012] Wherein, T1 is the outlet temperature of the spinneret, in °C; T2 is the temperature of the wind field, in °C; W is the humidity of the wind field, in %; V is the wind speed of the wind field, in m / s; h is the distance from the spinneret to the spinning bath, in mm;

[0013] The fineness of the Lyocell fiber is 0.9-1.1 dtex.

[0014] Preferably, the zero shear viscosity of the Lyocell fiber spinning dope at 85° C. is 6000 to 12000 Pa·s.

[0015] Preferably, the methylcellulose content of the Lyocell fiber spinning solution is 7 to 12 wt%.

[0016] Preferably, the Lyocell fiber spinning solution is prepared according to the following steps:

[0017] The pulp is mixed with a solvent to obtain pulp porridge; free water in the pulp porridge is then removed to obtain Lyocell fiber spinning dope.

[0018] Preferably, the pulp is kraft hardwood pulp or sulfite softwood pulp.

[0019] Preferably, the distance from the spinneret to the spinning bath is 10 to 30 mm.

[0020] Preferably, the wind speed of the wind field is 3-6 m / s.

[0021] Preferably, the spinning temperature of the spinneret is 95-105°C.

[0022] Preferably, the temperature of the wind field is 10-20°C.

[0023] Preferably, the humidity of the wind field is 75-85%.

[0024] Compared with the prior art, the present invention provides a method for producing Lyocell fiber, comprising the following steps: a) Lyocell fiber spinning glue passes through a filter and enters a spinning machine, and filaments are produced through a spinneret; b) the filament bundle produced by the spinneret enters a spinning bath for solidification and molding to obtain Lyocell fiber; the Lyocell fiber spinning glue has a zero shear viscosity of ≥6000Pa·s at 85°C, and a methyl cellulose content of ≤12wt%; the distance from the spinneret to the spinning bath is 10 to 50mm; a wind field is arranged between the spinneret and the spinning bath, and the wind direction of the wind field is Parallel to the spinneret; the outlet temperature of the spinneret and the temperature, humidity and wind speed of the wind field meet the following requirements: H = [(2T1-100) × T2 / 100] × [(T2-10) / 10 × (W / 100) + V / h], 4.5≤H≤10; wherein, T1 is the outlet temperature of the spinneret, unit ℃; T2 is the temperature of the wind field, unit ℃; W is the humidity of the wind field, unit %; V is the wind speed of the wind field, unit m / s; h is the distance from the spinneret to the spinning bath, unit mm; the fineness of the Lyocell fiber is 0.9 to 1.1 dtex. The production method provided by the present invention significantly reduces the product defects of 0.9 to 1.1 dtex Lyocell fibers by comprehensively adjusting multiple process parameters in the Lyocell fiber production process. Experimental results show that the defect content of 0.9 dtex Lyocell fibers produced by the method of the present invention is less than 5 mg / 100 g. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a method for producing Lyocell fiber, comprising the following steps:

[0027] a) Lyocell fiber spinning solution passes through the filter and enters the spinning machine, where it is filamented through the spinneret;

[0028] b) The filament bundles from the spinneret enter the spinning bath and are solidified and formed to obtain Lyocell fibers.

[0029] In the production method provided by the present invention, in step a), the zero shear viscosity of the Lyocell fiber spinning solution at 85°C is ≥6000Pa·s, preferably 6000-12000Pa·s, specifically 6000Pa·s, 6500Pa·s, 7000Pa·s, 7500Pa·s, 8000Pa·s, 8500Pa·s, 9000Pa·s, 9020Pa·s, 9500Pa·s, 10000Pa·s, 10500Pa·s, 11000Pa·s, 11500Pa·s or 12000Pa·s.

[0030] In the production method provided by the present invention, in step a), the methyl cellulose content of the Lyocell fiber spinning solution is ≤12wt%, preferably 7-12wt%, specifically 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt% or 12wt%.

[0031] In the production method provided by the present invention, in step a), the Lyocell fiber spinning dope is preferably prepared according to the following steps: mixing pulp with a solvent to obtain a pulp porridge; then removing free water from the pulp porridge to obtain a Lyocell fiber spinning dope. The pulp is preferably kraft hardwood pulp or sulfite softwood pulp; and the solvent is preferably an aqueous solution of N-methylmorpholine-N-oxide (NMMO).

[0032] In the production method provided by the present invention, in step b), the distance from the spinneret to the spinning bath is 10 to 50 mm, specifically 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm, most preferably 20 mm.

[0033] In the production method provided by the present invention, in step b), a wind field is arranged between the spinneret and the spinning bath to cool the filaments produced by the spinneret; the wind direction of the wind field is parallel to the spinneret.

[0034] In the production method provided by the present invention, in step b), the outlet temperature of the spinneret and the temperature, humidity and wind speed of the wind field meet the following requirements:

[0035] a=(2T1-100)×T2 / 100;

[0036] b=(T2-10) / 10×(W / 100)+V / h;

[0037] H = a × b;

[0038] 4.5≤H≤10;

[0039] Wherein, T1 is the outlet temperature of the spinneret (i.e., the temperature of the glue at the outlet hole of the spinneret), unit is °C; T2 is the temperature of the wind field, unit is °C; W is the humidity of the wind field, unit is %, V is the wind speed of the wind field, unit is m / s; h is the distance from the spinneret to the spinning bath, unit is mm.

[0040] In the production method provided by the present invention, in step b), the filament outlet temperature of the spinneret is preferably 95-105°C, specifically 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 102°C, 103°C, 104°C or 105°C.

[0041] In the production method provided by the present invention, in step b), the wind speed of the wind field is preferably 3-6 m / s, specifically 3 m / s, 3.5 m / s, 4 m / s, 4.5 m / s, 5 m / s, 5.5 m / s or 6 m / s.

[0042] In the production method provided by the present invention, in step b), the temperature of the wind field is preferably 10-20°C, specifically 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C or 20°C.

[0043] In the production method provided by the present invention, in step b), the humidity of the wind field is preferably 75-85%, specifically 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%.

[0044] In the production method provided by the present invention, in step b), H may specifically be 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10.

[0045] In the production method provided by the present invention, in step b), the fineness of the Lyocell fiber is 0.9-1.1 dtex, specifically 0.9 dtex, 0.95 dtex, 1 dtex, 1.05 dtex or 1.1 dtex.

[0046] In the production method provided by the present invention, in step b), the defect content of the Lyocell fiber is preferably <5 mg / 100 g.

[0047] The production method provided by the present invention significantly reduces the product defects of 0.9-1.1dtex Lyocell fibers by comprehensively adjusting multiple process parameters in the Lyocell fiber production process. Experimental results show that the defect content of 0.9dtex Lyocell fibers produced by the method of the present invention is less than 5mg / 100g.

[0048] For the purpose of greater clarity, the invention is described in detail through the following examples.

[0049] Example 1

[0050] (1) Preparation of spinning dope:

[0051] The pulp is kraft hardwood pulp with a polymerization degree of 440 mL g; the pulp is mixed with a solvent to obtain pulp porridge; free water in the pulp porridge is then removed to obtain Lyocell fiber spinning dope; the spinning dope has a methyl cellulose content of 11 wt % and a zero shear viscosity (85° C.) of 9020 Pa·s.

[0052] (2) Spinning:

[0053] The Lyocell fiber spinning dope passes through a filter and enters a spinning machine, where filaments are produced through a spinneret. The filaments then enter a spinning bath to be solidified and formed, thereby obtaining Lyocell fibers.

[0054] The distance between the spinneret and the spinning bath is set to 20 mm, and a wind field is set between the two, and the wind direction of the wind field is parallel to the spinneret;

[0055] The spinning quality under different conditions was investigated by adjusting the spinning temperature of the spinneret and the process parameters of the wind field; the test was conducted for 24 hours after each process adjustment, and the average value of the defect detection results of the day was taken as the evaluation result, which is as follows:

[0056]

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for producing Lyocell fiber, characterized in that: The following steps are involved: a) Lyocell fiber spinning solution passes through the filter and enters the spinning machine, where it is filamented through the spinneret; b) the filament bundles from the spinneret enter the spinning bath and are solidified and formed to obtain Lyocell fibers; The Lyocell fiber spinning solution has a zero shear viscosity of ≥6000 Pa·s at 85° C. and a methyl cellulose content of ≤12wt%; The distance between the spinneret and the spinning bath is 10 to 50 mm; A wind field is arranged between the spinneret and the spinning bath, and the wind direction of the wind field is parallel to the spinneret; The outlet temperature of the spinneret meets the following requirements with the temperature, humidity and wind speed of the wind field: H=[(2T1-100)×T2 / 100]×[(T2-10) / 10×(W / 100)+V / h], 4.5≤H≤10; Wherein, T1 is the outlet temperature of the spinneret, in °C; T2 is the temperature of the wind field, in °C; W is the humidity of the wind field, in %; V is the wind speed of the wind field, in m / s; h is the distance from the spinneret to the spinning bath, in mm; The fineness of the Lyocell fiber is 0.9-1.1 dtex.

2. The production method according to claim 1, characterized in that The zero shear viscosity of the Lyocell fiber spinning dope at 85° C. is 6000-12000 Pa·s.

3. The production method according to claim 1, characterized in that The methylcellulose content of the Lyocell fiber spinning solution is 7-12wt%.

4. The production method according to claim 1, characterized in that The Lyocell fiber spinning solution is prepared according to the following steps: The pulp is mixed with a solvent to obtain pulp porridge; free water in the pulp porridge is then removed to obtain Lyocell fiber spinning dope.

5. The production method according to claim 4, characterized in that: The pulp is kraft hardwood pulp or sulfite softwood pulp.

6. The production method according to claim 1, characterized in that: The distance between the spinneret and the spinning bath is 10 to 30 mm.

7. The production method according to claim 1, characterized in that: The wind speed of the wind field is 3-6 m / s.

8. The production method according to claim 1, characterized in that: The spinning temperature of the spinneret is 95-105°C.

9. The production method according to claim 1, characterized in that: The temperature of the wind field is 10-20°C.

10. The production method according to claim 1, characterized in that: The humidity of the wind field is 75-85%.

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