CN113980297A

CN113980297A - Method for preparing nitrocotton absorption plasticizer

Info

Publication number: CN113980297A
Application number: CN202111374927.8A
Authority: CN
Inventors: 袁满; 张仁旭; 马君; 邱清海; 王源; 阳洪
Original assignee: North Chemical Industry Co ltd
Current assignee: North Chemical Industry Co ltd
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2022-01-28

Abstract

The invention relates to a method for preparing a nitrocotton absorption plasticizer, which can effectively improve the uniformity of the plasticizer content distribution in a nitrocotton product, and comprises the following steps: a. dehydrating the boiled and washed nitrocotton for later use; b. preparing absorption water according to the required amount of 5-10% of the nitrocotton pulp; c. preparing a plasticizer; d. feeding the prepared nitrocotton, water and the plasticizer into a size mixing tank with stirring at the same time, wherein the stirring speed is 200-300r/min, the water and the plasticizer are firstly pumped into a mixer to be uniformly dispersed and then enter the size mixing tank, and the feeding time of the nitrocotton, the water and the plasticizer is the same; e. discharging the slurry mixing tank to an absorption tank with stirring while feeding, and continuously stirring for 25-45min to complete absorption after the absorption tank finishes feeding, wherein the stirring speed is 70-150 r/min; f. and e, dehydrating the slurry absorbed in the step e by a centrifugal machine until the water content is less than or equal to 35 percent to obtain the nitrocotton capable of uniformly absorbing the plasticizer. The method is particularly suitable for the preparation process of the nitrocotton absorption plasticizer.

Description

Method for preparing nitrocotton absorption plasticizer

Technical Field

The invention relates to the field of cellulose processing methods, in particular to a method for preparing a nitrocotton absorption plasticizer.

Background

The dry nitrocotton has the burning explosion characteristic, and industrial nitrocotton used for civil commercial circulation according to united nations and national regulations should be subjected to desensitization treatment and meet the corresponding standard regulations. The desensitized nitrocotton which usually keeps the plasticizer content of 18 percent or more is mainly processed by absorption, plasticization, molding, drying and the like, and the mixed absorption effect of the nitrocotton directly influences the subsequent process and the quality of the final product. The existing nitrocotton absorption process mainly mixes and absorbs nitrocotton and a plasticizer in a kneading machine, and the dispersion effect of the plasticizer is poor regardless of spraying or spraying feeding, the distribution uniformity of the plasticizer absorbed by the nitrocotton is poor all the time, the plasticizer is much remained on equipment, the content of the plasticizer in a product is not uniform, or the plasticizer exceeds the upper limit of an index or is lower than the lower limit of the index, the product quality is influenced, and potential safety hazards exist.

The Chinese patent publication No. CN109438146A discloses a process for producing nitrocellulose for indoor fireworks by a slurry method, which has the technical content that the nitrocellulose is plasticized and granulated, the fiber structure is eliminated, the shape is reshaped, and the obtained hardened granular material is different from the technical purpose of the invention that the plasticizer is uniformly distributed on the surface of the nitrocellulose and in the fiber cavity channel of the nitrocellulose.

Disclosure of Invention

The invention aims to provide a method for preparing nitrocotton absorption plasticizer, which can effectively improve the uniformity of the plasticizer content distribution in nitrocotton products.

The technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the nitrocotton absorption plasticizer comprises the following steps: a. preparation of nitrocotton: dehydrating the boiled and washed nitrocotton for later use, wherein the water content of the nitrocotton is 25-35%; b. preparation of water: preparing absorption water according to the required amount of 5-10% of the nitrocotton pulp; c. preparation of plasticizer: preparing a plasticizer according to the content of the plasticizer in the absolutely dry nitrocotton as a reference; d. size mixing: feeding the prepared nitrocotton, water and the plasticizer into a size mixing tank with stirring at the same time, wherein the stirring speed is 200-300r/min, the water and the plasticizer are firstly pumped into a mixer to be uniformly dispersed and then enter the size mixing tank, and the feeding time of the nitrocotton, the water and the plasticizer is the same; e. absorption: discharging the slurry mixing tank to an absorption tank with stirring while feeding, and continuously stirring for 25-45min to complete absorption after the absorption tank finishes feeding, wherein the stirring speed is 70-150 r/min; f. and (3) dehydrating: and e, dehydrating the slurry absorbed in the step e by a centrifugal machine until the water content is less than or equal to 35 percent to obtain the nitrocotton capable of uniformly absorbing the plasticizer.

Furthermore, in the step b, the addition amount of the plasticizer is determined according to the proportion that the plasticizer content in the absolutely dry nitrocotton is 19 percent.

Further, in step c, the plasticizer is DBP, ATBC or ESO.

Further, the mixer in step d is a jet mixer.

Further, the feeding time of the nitrocotton, water and the plasticizer in the step d is within a range of 15 min.

Further, the water removed in step f is temporarily stored in a tank for the next absorption.

The invention has the beneficial effects that: the invention sprays, mixes and emulsifies the plasticizer in water, and solves the problems of no dispersion and uneven dispersion of the plasticizer feeding control. Secondly, nitrocotton, plasticizer, water are simultaneously fed and contacted, the same feeding time is controlled, the size mixing tank with the transition function simultaneously feeds and discharges materials, and the materials are timely discharged to the absorption tank, so that the problem that the plasticizer is not uniformly absorbed due to the fact that the contact time is different is avoided. In addition, the nitrocotton absorbs the plasticizer in water, and the nitrocotton and the water can be continuously and fully dispersed by stirring, so that the mixing and the absorption are more thorough, and the plasticizer residue is basically avoided. Finally, the water for absorption can be recycled, and no waste water is generated. The method is particularly suitable for the preparation process of the nitrocotton absorption plasticizer.

Drawings

Fig. 1 is a schematic view of the equipment used in the present invention.

Labeled as: the device comprises a water inlet 1, a mixer 2, a plasticizer inlet 3, a nitrocotton inlet 4, a size mixing tank 5, an absorption tank 6, a centrifuge 7, a nitrocotton outlet 8 containing a plasticizer and a water recovery port 9.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The preparation method of the nitrocotton absorption plasticizer shown in figure 1 comprises the following steps: a. preparation of nitrocotton: dehydrating the boiled and washed nitrocotton for later use, wherein the water content of the nitrocotton is 25-35%; b. preparation of water: preparing absorption water according to the required amount of 5-10% of the nitrocotton pulp; c. preparation of plasticizer: preparing a plasticizer according to the content of the plasticizer in the absolutely dry nitrocotton as a reference; d. size mixing: feeding the prepared nitrocotton, water and the plasticizer into a size mixing tank 5 with stirring at the same time, wherein the stirring speed is 200-300r/min, the water and the plasticizer are firstly pumped to a mixer 2 for uniform dispersion and then enter the size mixing tank 5, and the feeding time of the nitrocotton, the water and the plasticizer is the same; e. absorption: discharging the slurry mixing tank 5 to an absorption tank 6 with stirring while feeding, and continuously stirring for 25-45min to finish absorption after the absorption tank 6 finishes feeding, wherein the stirring speed is 70-150 r/min; f. and (3) dehydrating: and e, dehydrating the slurry absorbed in the step e by a centrifugal machine 7 until the water content is less than or equal to 35 percent to obtain the nitrocotton capable of uniformly absorbing the plasticizer.

The invention aims at the characteristic of high requirement on the distribution uniformity of the plasticizer of a desensitization nitrocotton product, adopts wet absorption, takes water as a dispersion medium, and the plasticizer is sprayed, mixed and emulsified to obtain a uniform mixed solution of water and the plasticizer, and then the mixed solution is simultaneously fed and mixed with a certain amount of water-containing nitrocotton, and the plasticizer in the mixed solution is fully absorbed by the nitrocotton through continuous stirring, so that the plasticizers such as ATBC, ESO, DBP and the like are uniformly adsorbed on the surface of the mixed solution, and the original form of the nitrocotton is still maintained after the nitrocotton absorbs the plasticizer. And after the nitrocotton is absorbed, performing solid-liquid separation on the slurry, and recycling liquid-phase water in the slurry for cyclic utilization. Specifically, the method can fully disperse the plasticizer in water, and is favorable for uniform absorption of nitrocotton. Secondly, nitrocotton, plasticizer and water level are prepared and then fed for the same time, and a size mixing tank with a smaller volume is adopted for transition, so that the nitrocotton fed firstly is prevented from excessively absorbing the plasticizer. Meanwhile, the mixing tank stirs and spreads the nitrocotton in time, so that the mixing and absorption are more uniform. In addition, the water used as the dispersion medium can be directly recycled, no waste water is generated, and the cost is saved. Generally, it is preferred that the water removed in step f is temporarily stored in a tank for the next absorption.

In general, it is preferable that the amount of the plasticizer is determined at a ratio of 19% of the plasticizer content in the absolutely dry nitrocellulose in step b, so that the optimal amount of the plasticizer added is controlled. Preferably, in the step c, the plasticizer is DBP, ATBC or ESO, DBP (dibutyl phthalate), ATBC (acetyl tri-n-butyl citrate) and ESO (epoxidized soybean oil) are uniformly adsorbed on the surface of the nitrocotton, and the nitrocotton still keeps the original shape after absorbing the plasticizer.

In order to obtain a better jet mixing effect, it is preferred that the mixer 2 in step d is a jet mixer. In order to realize the simultaneous feeding of the nitrocotton, the plasticizer and the water for the same time after the levels are prepared and optimize the production efficiency, the feeding time of the nitrocotton, the water and the plasticizer in the step d is preferably within 15 min.

Examples

Example 1

400kg of H1/2 nitrocotton with 25% of water, 7600kg of water (the concentration of nitrocotton pulp is 5%), and 70.37kg of DBP plasticizer (calculated according to the absolute dry nitrocotton content of 19%) are prepared. Simultaneously feeding nitrocotton, water and DBP plasticizer into a size mixing tank with stirring, controlling the feeding time of each to be 15min, and controlling the stirring speed of the size mixing tank to be 300 r/min. Meanwhile, the slurry mixing tank feeds and discharges to an absorption tank with stirring, the stirring speed is 150r/min, the absorption tank feeds the slurry completely, and the slurry is continuously stirred for 25min to complete absorption. And (3) dehydrating the slurry after absorption, wherein the moisture content of the material is 28%, obtaining nitrocotton capable of uniformly absorbing the plasticizer, and performing subsequent processing treatment to obtain 5 samples, wherein the plasticizer content of the samples is within 18-20% of the quality index, and the average plasticizer content of the product is 18.99%, and the samples are uniformly distributed.

Example 2

400kg of H1/4 nitrocotton with 28% of water, 6266kg of water (the concentration of nitrocotton pulp is 6%), and 67.56kg of ESO plasticizer (calculated according to the absolute dry nitrocotton content is 19%) are prepared. Simultaneously feeding the nitrocotton, the water and the ESO plasticizer into a size mixing tank with stirring, wherein the feeding time of each is controlled to be 10min, and the stirring speed of the size mixing tank is 250 r/min. Meanwhile, the slurry mixing tank feeds and discharges to an absorption tank with stirring, the stirring speed is 110r/min, the absorption tank feeds the slurry completely, and the slurry is continuously stirred for 45min to complete absorption. And (3) dehydrating the slurry after absorption, wherein the water content of the material is 30 percent, obtaining nitrocotton which uniformly absorbs the plasticizer, and taking 5 samples to ensure that the plasticizer content is within 18-20 percent of the quality index and the average plasticizer content in the product is 18.98 percent and the distribution is very uniform through subsequent processing treatment.

Example 3

400kg of 35% water-containing L1/8 nitrocotton, 3600kg of water (the concentration of nitrocotton pulp is 10%), and 60.98kg of ATBC plasticizer (calculated according to 19% of absolutely dry nitrocotton) are prepared. Simultaneously feeding nitrocotton, water and an ATBC plasticizer into a size mixing tank with stirring, wherein the feeding time of each is controlled to be 8min, and the stirring speed of the size mixing tank is 200 r/min. Meanwhile, the slurry mixing tank feeds and discharges to an absorption tank with stirring, the stirring speed is 70r/min, the absorption tank feeds the slurry completely, and the slurry is continuously stirred for 35min to complete absorption. And (3) dehydrating the slurry after absorption, wherein the water content of the material is 31 percent, obtaining nitrocotton capable of uniformly absorbing the plasticizer, and taking 5 samples to ensure that the plasticizer content is within 18-20 percent of the quality index and the average plasticizer content in the product is 18.99 percent, wherein the samples are uniformly distributed.

The embodiment can obtain that the invention can effectively improve the uniformity of the plasticizer content distribution in the nitrocotton product, has very obvious technical advantages and has very wide market popularization prospect.

Claims

1. The preparation method of the nitrocotton absorption plasticizer is characterized by comprising the following steps:

a. preparation of nitrocotton: dehydrating the boiled and washed nitrocotton for later use, wherein the water content of the nitrocotton is 25-35%;

b. preparation of water: preparing absorption water according to the required amount of 5-10% of the nitrocotton pulp;

c. preparation of plasticizer: preparing a plasticizer according to the content of the plasticizer in the absolutely dry nitrocotton as a reference;

d. size mixing: feeding the prepared nitrocotton, water and the plasticizer into a size mixing tank (5) with stirring at the same time, wherein the stirring speed is 200-;

e. absorption: discharging the slurry mixing tank (5) to an absorption tank (6) with stirring while feeding, and after the absorption tank (6) finishes feeding, continuously stirring for 25-45min to finish absorption, wherein the stirring speed is 70-150 r/min;

f. and (3) dehydrating: and (e) dehydrating the slurry absorbed in the step (e) by a centrifugal machine (7) until the water content is less than or equal to 35 percent, thereby obtaining the nitrocotton capable of uniformly absorbing the plasticizer.

2. The method for preparing nitrocotton absorption plasticizer according to claim 1, characterized in that: in the step b, the addition amount of the plasticizer is determined according to the proportion that the plasticizer content in the absolutely dry nitrocotton is 19 percent.

3. The method for preparing nitrocotton absorption plasticizer according to claim 1 or 2, characterized in that: in step c, the plasticizer is DBP, ATBC or ESO.

4. The method for preparing nitrocotton absorption plasticizer according to claim 1 or 2, characterized in that: the mixer (2) in the step d is a jet mixer.

5. The method for preparing nitrocotton absorption plasticizer according to claim 1 or 2, characterized in that: the feeding time of the nitrocotton, the water and the plasticizer in the step d is within 15 min.

6. The method for preparing nitrocotton absorption plasticizer according to claim 1 or 2, characterized in that: and f, temporarily storing the water removed in the step f by using a groove for the next absorption.