CN101089257B - Stabilizing agent for cellulose fibre prepared by solvent method - Google Patents

Abstract

A stabilizer for preparing cellulose fiber by a solvent method, the weight percentage of propyl benoate is 0.3-1%, the weight percentage of NMMO solvent propyl benoate is 99-99.7%, and the concentration of NMMO solvent is 40-50% . Using the propyl benicate solution prepared by the present invention as a stabilizer can solve the shortcomings of the stabilizer solution, such as easy crystallization at low temperature, during the production process of cellulose fiber slurry preparation, and is easy to control, simple and accurate.

Description

A kind of solvent method prepares stabilizer for cellulose fiber

technical field

The present invention relates to a kind of stabilizer that solvent method prepares cellulose fiber, more specifically, the present invention relates to a kind of propyl benoate (Propyl-3,4,5-trihydroxybenzoate for used in the production of cellulose fiber) synthesis) solution.

Background technique

Cellulose fiber is known as the green fiber of the 21st century. The main raw material pulp and solvent NMMO (N-methylmorpholine N oxide) are added to the equipment in a certain proportion, mixed and homogenized, dehydrated until dissolved and homogenized to become a spinning slurry, through spinning and a series of After processing, the finished fiber is obtained. However, when cellulose pulp is dissolved in NMMO solution at a certain temperature, the degree of polymerization of cellulose will decrease, especially in the presence of metal ions, which will cause cellulose macromolecular chains to break and cellulose to degrade. On the other hand, the thermal stability of NMMO is limited, and its thermal stability varies with the structure. When cellulose is mixed with a solvent and heated, the solvent NMMO will degrade and release amine compounds, such as N-methylmorpholine and morpholine , as the degradation proceeds, the solution viscosity decreases and the color becomes darker. In order to prevent oxidative degradation of cellulose and solvents during the dissolution process, an appropriate amount of stabilizer is usually added during the dissolution process. At present, the most widely used in the world is to use the antioxidant propyl bedecate as a stabilizer, so that the cellulose solution obtained after dissolution It has good stability and high viscosity and thermoplasticity.

Since propyl berionate is in the form of solid particles, the amount of addition is small, and it needs to be added synchronously with cellulose and solvent in proportion, which is quite difficult to control. Therefore, it is generally dissolved with a solvent, prepared into a propyl benoate solution, and then mixed with Cellulose and solvent are added to the dissolving system in a certain proportion. For example: the technology of East Thuringia Institute of Textile and Plastics (TITK) in Germany uses propyl benicate as a stabilizer. A solution is prepared by dissolving the propyl bedecate in a solvent with a concentration of more than 60% NMMO. However, the solution prepared in this way needs to be equipped with a hot water insulation system to accurately control the temperature of the solution, otherwise it will crystallize when the room temperature is lower than 19°C, which requires a high temperature control capability in technology, especially in winter. In the spring season, a matching thermal insulation system must be used to ensure the production needs, which increases the production cost.

In preparing the propyl benoate solution as a stabilizer, the lower the concentration of NMMO is used as a solvent to prepare the propyl benoate solution, the less likely it is to produce crystallization, but if the concentration of NMMO as a solvent is low, it will give cellulose The dissolving system brings in more water, which will increase the dissolving load of the subsequent section, thereby affecting the normal operation of the entire spinning process.

Contents of the invention

In order to solve the problems in the above-mentioned production, the object of this invention is to provide a kind of solvent method to prepare used in the cellulose fiber dissolving process, which is difficult to crystallize, easy to control, effective and economical stabilizer --- propyl benicate solution.

The propyl benicate solution used in the cellulose fiber dissolving process of the present invention is:

The weight percentage of propyl bembinoate is 0.3～1%

The weight percentage of NMMO solvent is 99～99.7%

The concentration of the above-mentioned NMMO solvent is 40-50%.

In the present invention, the weight percent content of propyl benicate in the solution is preferably 0.5-0.7%, and the preferred concentration of NMMO solvent is: 45-47%.

The preparation method of propyl benicate solution of the present invention is:

First prepare the NMMO solvent with a concentration of 40-50%, and then dissolve the propyl becinoate in the 40-50% NMMO solvent.

Adopt the propyl benicate solution prepared by the present invention as stabilizer, in the production of solvent method cellulose fiber, can effectively avoid this solution to produce crystallization at low temperature, especially in winter and spring season when air temperature is low, can not use Any insulation equipment used in the production of solvent-processed cellulose fibers. Simultaneously using the propyl betinate solution of the present invention as a stabilizing agent can also avoid the problem that more water will be brought into the cellulose dissolving system when the concentration of NMMO as a solvent is lower than 40%, and the system can be effectively controlled. stability.

The cellulose fiber spinning slurry produced by using the present invention as a stabilizer is tested by the inspection standard of TITK in Germany, and all indexes are in compliance with relevant international standards.

Using different concentrations of NMMO solutions as solvents, the crystallization temperature of the prepared propyl benoate solution can be seen in Table 1.

Table 1

As can be clearly seen from Table 1, when using NMMO with a concentration higher than 50% as a solvent to prepare propyl becinoate solution, its crystallization temperature is significantly higher than using NMMO with a concentration below 50% as a solvent, that is to say using this The inventive propyl benoate solution as a stabilizer can well solve the problem that the propyl benoate solution is prone to crystallization at low temperature, and will not bring more water into the system during production and application.

Detailed ways

The method for preparing propyl benicate solution of the present invention is followed by the following steps successively:

1) Dilute the commercially available NMMO solution with a concentration of about 50% to about 10% to 40% with deionized water, and then purify it with anion and yang resins to remove color and impurities;

2) Concentrating the purified solution under the conditions of 10-15kpa and 50-70°C to a concentration of 40-50%;

3) Take out the NMMO solution of this concentration, add the required amount of propyl bedecate, and stir it with a stirrer to mix it evenly.

The propyl berconate used in the examples is produced by MERCK; the water cellulose used is that the SAPPI company's pulp is dehydrated to 20-55% by soaking in water, and pulverized, or is dehydrated to 20% by activation with the SAPPI company's pulp. ~55%, obtained by crushing.

Example 1

In a tank with a low-speed stirrer, add 99.1% by weight of NMMO solvent with a concentration of 43%, then add 0.9% by weight of propyl becate, and stir with a stirrer to make it a uniform solution.

Add the solution prepared above, 200kg of water cellulose and 682kg of 88% NMMO solvent into the dissolving machine synchronously in proportion, and dissolve under the conditions of 1-10kpa and 75-115°C to obtain spinning slurry. The size test standard of the Institute of Textile and Plastics (TITK) was tested, and the results are shown in Table 1.

Example 2

In a tank with a low-speed stirrer, add 99.3% by weight of NMMO solvent with a concentration of 45%, then add 0.7% by weight of propyl bedecate, and stir with a stirrer to make it a uniform solution.

Add the solution prepared above, 200kg of water cellulose and 711kg of 84% NMMO solvent into the dissolving machine synchronously in proportion, and dissolve under the conditions of 1-10kpa and 75-115°C to obtain spinning slurry. The size test standard of the Institute of Textile and Plastics (TITK) was tested, and the results are shown in Table 1.

Example 3

In a tank with a low-speed stirrer, add 99.5% by weight of NMMO solvent with a concentration of 47%, then add 0.5% by weight of propyl bedecate, and stir with a stirrer to make it a uniform solution.

Add the solution prepared above, 200kg of water cellulose and 732kg of 81% NMMO solvent into the dissolving machine synchronously in proportion, and dissolve under the conditions of 1-10kpa and 75-115°C to obtain spinning slurry. The size test standard of the Institute of Textile and Plastics (TITK) was tested, and the results are shown in Table 1.

Example 4

Adding the concentration of 99.6% by weight in a tank with a low-speed stirrer is a 49% NMM0 solvent, and then adding 0.4% by weight of propyl bedecate, stirring with a stirrer to make it a uniform solution.

Add the solution prepared above, 200kg of water cellulose and 755kg of 78% NMMO solvent into the dissolving machine synchronously in proportion, and dissolve under the conditions of 1-10kpa and 75-115°C to obtain spinning slurry. The size test standard of the Institute of Textile and Plastics (TITK) was tested, and the results are shown in Table 2.

Table 2

The test data of each embodiment in Table 2 shows that the quality of the resulting slurry meets the current international cellulose fiber spinning process requirements, that is, the propyl benoate solution of the present invention has played the role of a stabilizer well.

Claims (2)

1. stabilizing agent for cellulose fibre prepared by solvent method is characterized in that:

The percentage by weight of bud propyl propionate is 0.3～1%

The percentage by weight of NMMO solvent is 99～99.7%

The concentration of above-mentioned NMMO solvent is 45～47%.

2. stabilizing agent for cellulose fibre prepared by solvent method according to claim 1, feature are that the weight percent content of described bud propyl propionate is: 0.5～0.7%.