Process for the preparation of EG-tio2, eg-tio2-nmmo dispersion, and fully-dull lyocell fibers

Abstract

The application discloses an EG-TiO2, an EG-TiO2-NMMO dispersion liquid and a preparation method of a full-dull lyocell fiber. The preparation method of the EG-TiO2 comprises the following steps: S11, adding tetrabutyl titanate into an ethylene glycol solution, stirring until the solution is colorless and transparent, and obtaining a solution 1; S12, adding ultrapure water into the solution 1 drop by drop, then heating the solution 1, and obtaining a solution 2; S13, adding ethanol and diethyl ether into the solution 2, obtaining a solution 3, centrifuging the solution 3, and filtering to obtain solid EG-TiO2. The application provides a preparation method of the EG-TiO2, the EG-TiO2-NMMO dispersion liquid and the full-dull lyocell fiber, which can avoid the blockage of the spinneret hole by titanium dioxide powder during spinning.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lyocell fiber preparation, in particular, to a preparation method of EG-TiO2, EG-TiO2-NMMO dispersion and full-dull lyocell fiber. BACKGROUND

[0002] Lyocell fiber is a cellulose fiber prepared by directly dissolving a glue solution with cellulose as raw material and NMMO as solvent, and then through dry spraying and wet spinning. Due to the relatively smooth surface of lyocell fiber, the intensity of reflected light is very high under strong light irradiation, which looks like an uncomfortable strong luster in naked eyes, and even can cause dizziness. In industry, the visual effect can be effectively improved by adding a substance with different refractive index to make the light be diffusely reflected in multiple directions during fiber production or post-treatment.

[0003] At present, there are two main ways for the dull treatment of lyocell fiber. The first way is to add a dulling agent during the preparation of the original glue solution, and the second way is to perform dull treatment in post-treatment after the glue solution is spun into a shape. The durability and dull effect of the second method are not good, and it is basically not used in actual production.

[0004] The first way is to directly add anatase titanium dioxide into N-methyl morpholine-N-oxide aqueous solution, and then add the slurry, and then prepare the glue solution under the conditions of stirring and vacuum, and then obtain the dull lyocell fiber after spinning and shaping. However, the dispersibility of anatase titanium dioxide in N-methyl morpholine-N-oxide aqueous solution (NMMO) is not good, and it is difficult to uniformly distribute in the solution, so the spinneret is easily blocked during the subsequent spinning. SUMMARY

[0005] The summary section of the present application is used to introduce the concepts in a brief form, which will be described in detail in the following detailed description section. The summary section of the present application is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0006] As a first aspect of the present application, in order to solve the problem that the water solubility of the metal oxide of titanium in NMMO is not good, which affects the large-scale preparation of lyocell fiber, some embodiments of the present application provide a preparation method of EG-TiO2, comprising the following steps:

[0007] S11: Tetra-n-butyl titanate is added into an ethylene glycol solution, and the solution is stirred until the solution is colorless and transparent, to obtain a solution 1.

[0008] S12: Ultra-pure water is added dropwise into the solution 1, and then the solution 1 is heated, and then a solution 2 is obtained.

[0009] S13: adding ethanol and ether into solution 2 to obtain solution 3, and centrifuging solution 3 to obtain solid EG-TiO2.

[0010] In this scheme, the prepared solid EG-TiO2 is obtained by inserting EG into the original titanium dioxide, so that the titanium dioxide has the original extinction ability and certain water solubility. Therefore, EG-TiO2 has good water solubility in aqueous solution, so that it can be mixed into NMMO solution to make it easier to disperse, thereby having good dispersibility in NMMO, and then applying it to the production of lyocell fibers, which can rely on its good dispersibility in NMMO solution to prevent the spinneret from being blocked during spinning.

[0011] Further, in S11, the volume ratio of tetrabutyl titanate to ethylene glycol is 1:50.

[0012] Further, in S12, the solution 1 is heated by reflux reaction.

[0013] In this scheme, the reflux reaction can avoid the loss of solvent in the solution and ensure that the temperature of the solution is within a controllable range.

[0014] As a second aspect of the present application, in order to solve the problem of poor dispersibility of titanium metal oxide in NMMO solution, in some embodiments of the present application, the following technical scheme is provided: a preparation method of EG-TiO2-NMMO dispersion liquid includes the following steps:

[0015] Step S21: adding solid EG-TiO2 powder into NMMO solution to obtain solution I.

[0016] Step S22: adjusting the pH value of solution I, and then stirring until the solution is uniformly distributed to obtain EG-TiO2-NMMO dispersion liquid. In this scheme, adjusting the pH value of solution I can adjust the distribution of EG-TiO2 in the solution, thereby maximizing the dispersion efficiency of EG-TiO2 in the EG-TiO2-NMMO dispersion liquid.

[0017] Further, in S21, the particle size of the EG-TiO2 powder is 50-300. When the particle size of the EG-TiO2 powder is in the range of 50-300, the scattering effect is best when the particle size is about half the wavelength of visible light.

[0018] Further, in S21, the particle size of the EG-TiO2 powder is 200-250. The human eye is most sensitive to visible light with a wavelength of 555 nm, and the extinction effect is best when the particle size of TiO2 is about 200-250 nm.

[0019] Further, in S22, the PH value of solution I is adjusted to 9-11. In an acidic environment, the water solubility of EG-TiO2-NMMO is better, and the dispersion effect is better.

[0020] Further, in S22, the PH value of solution I is adjusted to 11.

[0021] As a third aspect of the present application, in order to solve the problem that the metal oxide of titanium is difficult to disperse into the NMMO solution, and the spinneret hole is blocked in the subsequent production of lyocell fibers, some embodiments of the present application provide a preparation method of full-dull lyocell fibers, comprising the following steps: dissolving pulp into an EG-TiO2-NMMO dispersion solution to prepare full-dull lyocell fibers.

[0022] In the present scheme, the EG-TiO2-NMMO dispersion solution is prepared first, and then the pulp is put into the EG-TiO2-NMMO dispersion solution, so it is a solution and a solution mixture. During mixing, it can be mixed more uniformly. Compared with the existing scheme of adding titanium dioxide and pulp into the NMMO solution, the liquid and liquid mixing scheme, the mixing is more uniform, and the dispersion effect of EG-TiO2-NMMO in the pulp is better.

[0023] The present application has the following advantages:

[0024] 1. The present application improves the polarity of TiO2 after modification treatment, and the dispersion is good and not easy to agglomerate. The method is simple, easy to prepare, and low in cost.

[0025] 2. The present application prepares TiO2 glue solution first, and then mixes with the subsequent solution, which has high dispersion efficiency and good distribution effect, saving time and labor.

[0026] 3. The present application improves the preparation of full-dull lyocell fibers, which has simple process, short flow, wide application range, and the treated fiber has obvious improvement in gloss, and the effect is still maintained after multiple washing treatments.

[0027] 4. According to the characteristic test and selection of suitable spinning conditions, the prepared full-dull lyocell fiber has excellent mechanical properties, high spinnability, high yield, and good dull effect. DETAILED DESCRIPTION

[0028] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The schematic embodiment drawings of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application.

[0029] In addition, throughout the drawings, same or similar reference numerals can denote same or similar elements throughout the several views. It is to be understood that the drawings are schematic, and elements and features are not necessarily drawn to scale.

[0030] In the drawings:

[0031] Figure 1 Flow chart of the preparation method of full-dull lyocell fiber;

[0032] Figure 2 Photo of the distribution of titanium dioxide in NMMO solution under a scale of 500 nm. DETAILED DESCRIPTION

[0033] Embodiments of the present disclosure will be described in more detail with reference to the drawings. Although certain embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be interpreted as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly and completely understood. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0034] It should also be noted that, for ease of description, only parts related to the present application are shown in the drawings. The embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0035] The present disclosure will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0036] Embodiment 1: Preparation method of EG-TiO2, comprising the following steps:

[0037] S11: Tetra-n-butyl titanate is added to a glycol solution, and stirred until the solution is colorless and transparent to obtain solution 1.

[0038] S12: Ultra-pure water is added dropwise to solution 1, and then solution 1 is heated to obtain solution 2.

[0039] S13: Ethanol and diethyl ether are added to solution 2 to obtain solution 3, and solution 3 is centrifuged and filtered to obtain solid EG-TiO2.

[0040] The specific manner of steps S11-S12 is as follows:

[0041] 1 mL of tetra-n-butyl titanate is added dropwise to 50 mL of a glycol solution with a volume fraction of 50%, and stirred for 30 min to obtain a colorless and transparent solution 1. In this way, step S11 is completed.

[0042] Then, 30ml of ultrapure water is added dropwise to solution 1, and solution 1 is heated to 120°C in a water bath, and refluxed for 2h. After the reaction is completed, the temperature of the reaction solution is reduced to room temperature to obtain solution 2. Thus, step S12 is completed. In the reflux reaction, the solvent volatilized can be condensed through a condenser tube, so that the solvent volatilized from the reaction system returns to the system and reacts. During cooling, natural cooling or cold water can be used for heat exchange.

[0043] Then, 20ml of anhydrous ethanol and 20ml of anhydrous ether are added to solution 2 to obtain solution 3, which is stirred for 5-10min. After solution 3 is left to precipitate, it is centrifuged at 9000rpm for 20min, filtered to obtain a solid product, which is then repeatedly washed with a mixture of anhydrous ethanol and anhydrous ether in a ratio of 1:1, and dried at 60°C to obtain solid EG-TiO2.

[0044] Example 2: Preparation method of EG-TiO2-NMMO dispersion liquid

[0045] Step S21: Solid EG-TiO2 powder is added to NMMO solution to obtain solution I.

[0046] Step S22: The PH value of solution I is adjusted to 11, and then stirred until the solution is uniformly distributed.

[0047] Specifically, the following steps are included: solid EG-TiO2 is ground to a particle size of 100nm to obtain EG-TiO2 powder, which is added to a NMMO solution with a concentration of 20-30%, so that the mass fraction of EG-TiO2 in the solution is 0.5%. Then, NaOH solution is added dropwise to the solution to adjust the PH value of the solution to 11, and then stirred at an amplitude of 30-60% for 10-20min until the solution is uniformly distributed.

[0048] When solid EG-TiO2 is ground to 100nm: the concentration and temperature of the NMMO solution are changed to obtain the following data:

[0049] Table 1: Dispersion degree of EG-TiO2-NMMO dispersion liquid obtained at different PH values

[0050]

[0051]

[0052] Table 2: Dispersion degree of EG-TiO2-NMMO dispersion liquid obtained at different NMMO concentrations

[0053]

[0054] Table 3: dispersity of EG-TiO2-NMMO dispersion obtained at different reaction temperatures

[0055] Temperature Dispersion 0 50％ 10 59％ 20 79％ 30 88％ 40 89％ 50 75％ 60 72％

[0056] Therefore, in combination with the above single factor analysis, the best dispersion effect can be obtained when the temperature is 40 degrees Celsius, the NMMO concentration is 20-30%, and the pH is 11.

[0057] Example 3: A method for preparing fully-dull lyocell fibers, comprising the following steps: dissolving pulp into the EG-TiO2-NMMO dispersion; and subsequently performing dissolution, homogenization bubble removal, filtration, spinning, cutting, water washing, oiling, and packaging to obtain fully-dull lyocell fibers.

[0058] In the preparation of lyocell fibers, the pulp is dissolved in the NMMO solution, and then dissolution, homogenization bubble removal, filtration, spinning, cutting, water washing, and oiling are performed. In this scheme, the NMMO solution used in the preparation of traditional lyocell fibers is replaced by the EG-TiO2-NMMO dispersion, and therefore the specific dissolution, homogenization bubble removal, filtration, spinning, cutting, water washing, and oiling are not described in detail in this example.

[0059] Reference Figure 2 The reaction principle of the present application is as follows: TiO2 is surface-modified by using an in-situ surface modification method. The modified TiO2 has hydrophilicity, and an adsorbed thin layer is formed on the surface of the nanoparticles, which generates a certain steric hindrance between the nanoparticles, thereby reducing the surface tension of the nanoparticles and inhibiting the agglomeration of the nanoparticles, so that the nanoparticles are more easily dispersed in the NMMO solution. The addition of TiO2 in lyocell fibers makes the overall refractive index of the fibers uneven, causing the light to be diffusely reflected in multiple directions, rather than directly reflected, thereby effectively improving the visual effect.

[0060] The preparation principle of lyocell fibers is as follows: the structure of pulp itself has naturally imperfect voids, small molecules of NMMO and water can enter the voids inside the fibers, causing the cellulose to swell to a certain extent, and NMMO can form hydrogen bonds with the hydroxyl groups of cellulose, so that the cellulose can be completely dissolved in the solution to form a spinning solution. The spinning solution passes through the spinneret to form fibers, and the fibers are subsequently subjected to bidirectional diffusion in a low-concentration NMMO water bath, and the fibers are precipitated out. With multiple water washings, the content of NMMO in the fibers gradually decreases, and finally pure cellulose fibers are obtained.

[0061] Because the extinction ratio of EG-TiO2 with different particle sizes is not consistent for human eye, solid EG-TiO2 with different particle sizes is used to prepare EG-TiO2-NMMO dispersion, and then Lyocell fibers are prepared using the different EG-TiO2-NMMO dispersions to obtain the following data.

[0062] Table 4 Diffuse reflectance of EG-TiO2 with different particle sizes

[0063] Particle size Visible diffuse reflectance 50 nm 50％ 100 nm 56％ 150 nm 57％ 200 nm 59％ 250 nm 50％ 300 nm 47％

[0064] It can be seen that the extinction effect is the best when the particle size is 100-150 nm.

[0065] The above description is merely some preferred embodiments of the present disclosure and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features without departing from the above inventive concept. For example, the above features are replaced with each other to form technical solutions with similar functions disclosed in the embodiments of the present disclosure (but not limited to).

Claims

1. A process for the production of a fully-dull lyocell fiber, characterized in that, Dissolve the pulp into a dispersion liquid to prepare full-dull lyocell fiber, the dispersion liquid is prepared by the following method, including the following steps: S11: add tetrabutyl titanate into ethylene glycol solution, stir until the solution is colorless and transparent, to obtain solution 1; S12: add ultrapure water into solution 1 drop by drop, then heat solution 1, to obtain solution 2; S13: add ethanol and diethyl ether into solution 2, to obtain solution 3, centrifuge solution 3, filter to obtain solid EG-TiO2; S21: add solid EG-TiO2 powder into NMMO solution to obtain solution I; S22: adjust the PH value of solution I, then stir until the solution is uniformly distributed, to obtain EG-TiO2-NMMO dispersion liquid; The particle size of EG-TiO2 powder in S21 is 100-200 nm, the temperature is 40 degrees Celsius, the NMMO concentration is 20-30%, and the PH is 11.

2. The process for the production of a full-dull lyocell fiber according to claim 1, characterized in that: In S11, the volume ratio of tetrabutyl titanate and ethylene glycol is 1:

50.

3. The process for producing a full-dull lyocell fiber according to claim 1, characterized by: In S12, solution 1 is heated by reflux reaction.

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