阅读说明：本技术 一种阻燃型微胶囊及其制备方法和应用 (Flame-retardant microcapsule and preparation method and application thereof ) 是由 张林雅 于 2019-11-29 设计创作，主要内容包括：本发明公开了阻燃型微胶囊及其制备方法和应用。所述阻燃型微胶囊,包括芯材和壁材,所述壁材包括明胶和半纤维素,所述芯材包括阻燃剂。本发明采用复凝聚法以上述壁材和芯材为原料制备得到的阻燃型微胶囊,其包埋率可达87.6％,粒径最大为0.94m,应用于阻燃粘胶纤维制备中,水洗后阻燃剂留存率可达98.3％,极限氧指数可达34.1％,垂直燃烧达到了V-0级,有效解决了目前阻燃剂与粘胶纤维相容性差以及植物资源循环再利用问题,且制备方法操作简便易行,成本低廉,绿色环保,同时该微胶囊壁材具有可降解性,具备良好的经济效益和发展前景。(The invention discloses a flame-retardant microcapsule, a preparation method and application thereof. The flame-retardant microcapsule comprises a core material and a wall material, wherein the wall material comprises gelatin and hemicellulose, and the core material comprises a flame retardant. The flame-retardant microcapsule prepared by adopting the wall material and the core material as raw materials by adopting a complex coacervation method has an embedding rate of 87.6 percent and a maximum particle size of 0.94m, is applied to the preparation of flame-retardant viscose fibers, has a flame retardant retention rate of 98.3 percent after washing and a limited oxygen index of 34.1 percent, achieves the V-0 level of vertical combustion, effectively solves the problems of poor compatibility of the conventional flame retardant and the viscose fibers and the recycling of plant resources, has simple and easy operation, low cost and environmental protection, and has good economic benefit and development prospect.)

1. The flame-retardant microcapsule comprises a core material and a wall material, and is characterized in that the wall material comprises gelatin and hemicellulose, and the core material comprises a flame retardant.

2. The flame-retardant microcapsule according to claim 1, wherein the mass ratio of the core material to the wall material is 1:1.2 to 1.6.

3. The flame-retardant microcapsule according to claim 1, wherein the mass ratio of hemicellulose to gelatin is 1.2-1.4: 1.

4. The flame-retardant microcapsule according to claim 1, wherein the hemicellulose comprises the following sugar units in percentage by mass: 75-83% of xylose, 10-12% of mannose, 6-11% of glucose, 0.9-1.4% of galactose and less than 0.8% of glucuronic acid.

5. The flame-retardant microcapsule according to claim 1, wherein said flame retardant is a dithiophosphate flame retardant.

6. The process for preparing a flame-retardant microcapsule according to any one of claims 1 to 5, comprising the steps of:

step one, weighing each component according to a design ratio, and dissolving the weighed gelatin and hemicellulose in water to obtain a wall material solution;

dissolving the weighed flame retardant in water, adding a dispersing agent and an emulsifying agent, and uniformly mixing to obtain a core material emulsion;

and step three, uniformly mixing the wall material solution and the core material emulsion, adjusting the pH value to 3.4-4.8, adding a curing agent, and curing at 45-65 ℃ for 3-6h to obtain the flame-retardant microcapsule.

7. The preparation method of the flame-retardant microcapsule according to claim 6, wherein in the first step, the mass concentration of gelatin in the wall material solution is 5.1-5.6 wt%; and/or

In the second step, the mass ratio of the flame retardant to the water is 1: 9-12.

8. The method for preparing the flame-retardant microcapsule according to claim 6, wherein in the second step, the dispersant is sorbitan fatty acid ester; and/or

The emulsifier is OP-10; and/or

The curing agent is formaldehyde solution with the mass concentration of 35-40 wt%.

9. The process for preparing a flame-retardant microcapsule according to claim 6 or 8, wherein the dispersant is added in an amount of 4.5 to 5.5 wt% based on the mass of the flame retardant; and/or

The addition amount of the emulsifier is 2.8-3.2 wt% of the mass of the flame retardant;

the addition amount of the curing agent is 1-1.2 times of the mass of the wall material.

10. Use of the flame retardant microcapsule according to any one of claims 1 to 5 for the preparation of flame retardant viscose fibres.

Technical Field

The invention relates to the technical field of flame-retardant materials, in particular to a flame-retardant microcapsule and a preparation method and application thereof.

Background

Viscose is an important regenerated cellulose fiber, and has excellent wearability such as wearing comfort and natural degradation. With the continuous improvement of living standard and industrial application requirement of people, the functionality and environmental protection of people are generally concerned by consumers, and the improvement of product performance becomes the key of the development of high-quality functional viscose fiber technology. The flame-retardant viscose fiber is an important variety in modified viscose fiber, not only retains the good clothes performance and dyeing performance of the viscose fiber, but also has better flame-retardant performance, improves the safety of viscose fiber textiles, and has wide market prospect. The existing industrialized flame-retardant viscose fiber product is mainly produced by adopting a blending flame-retardant modification technology, the method is to directly add a flame retardant into a viscose production stock solution, the flame retardant is mostly phosphorus, the method has the advantages of simplicity and easy control, but the flame retardant is easy to fall off through a subsequent washing process due to the poor compatibility of the existing flame retardant and cellulose, so that the performance of the flame-retardant viscose fiber is poor.

Therefore, a new flame retardant is needed to solve the problem of poor compatibility between the flame retardant and cellulose. Improving the flame retardance and the washability of the viscose fiber is a key problem to be solved urgently in the research field of the flame-retardant viscose fiber at present.

Disclosure of Invention

Aiming at the problem that the flame-retardant viscose fiber in the prior art has poor compatibility between a flame retardant and the viscose fiber, so that the flame-retardant effect and the washing resistance are poor, the invention provides the flame-retardant microcapsule and the preparation method and the application thereof.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the flame-retardant microcapsule comprises a core material and a wall material, wherein the wall material comprises gelatin and hemicellulose, and the core material comprises a flame retardant.

Aiming at the problems of poor flame retardant performance, non-lasting flame retardant effect and poor washability caused by poor compatibility of a flame retardant and viscose fibers in the modification of the existing blended flame retardant viscose fibers, the invention selects hemicellulose and gelatin as wall materials, the hemicellulose contains a large amount of xylose, besides hydroxyl carried by a main chain, a branched chain also has acetyl and glucose aldehyde groups, the steric effect caused by overlong main chain can be eliminated, a space cross-linked network structure is easily formed with gelatin macromolecules, the strength and toughness of the wall materials are enhanced, the embedding rate and the flame retardant stability of microcapsules are greatly improved, and meanwhile, the preparation of the flame retardant microcapsules with the particle size of less than 1 mu m is facilitated. The flame-retardant microcapsule prepared by the invention is added into cellulose stock solution of viscose, a large amount of free hydroxyl in the cellulose stock solution is easy to form strong binding force with wall materials consisting of hemicellulose, the compatibility of a flame retardant and the viscose is obviously enhanced, and the flame retardant property and the washing resistance of the viscose are greatly improved.

The embedding rate of the flame-retardant microcapsule prepared by the invention can reach 87.6%, the limiting oxygen index can reach more than 34.1%, the vertical combustion can reach V-0 level, the flame retardant retention rate is high when the microcapsule is applied to viscose fibers, the retention rate of the flame retardant after washing is more than 96%, the falling of the flame retardant in the washing process is effectively avoided, and meanwhile, the flame-retardant microcapsule prepared by the invention has small particle size, meets the requirement of small aperture of viscose fiber production equipment, and has good economic benefit and development prospect.

Preferably, the mass ratio of the core material to the wall material is 1: 1.2-1.6.

The preferable mass ratio of the core material to the wall material is favorable for better coating the core material, improves the embedding rate of the microcapsule and prevents the core material from leaking.

Preferably, the mass ratio of the hemicellulose to the gelatin is 1.2-1.4: 1.

The preferable mass ratio of the gelatin to the hemicellulose is favorable for forming a wall material with high polymerization degree and good stability, so that the capsule wall has better compactness and integrity, and the core material can be better protected.

Optionally, the hemicellulose is extracted from waste viscose fiber production liquid.

Preferably, the hemicellulose comprises the following components in percentage by mass: 75-83% of xylose, 10-12% of mannose, 6-11% of glucose, 0.9-1.4% of galactose and less than 0.8% of glucuronic acid.

The preferable hemicellulose has higher xylose content, and besides the hydroxyl group of the main chain, the branched chain also has acetyl and glucose aldehyde group, so that the steric effect caused by overlong main chain can be eliminated, the hemicellulose and gelatin can be more favorably adsorbed and condensed, the shell layer of the microcapsule is more compact, and the microcapsule with the grain diameter of less than 1 mu m can be prepared.

Alternatively, the flame retardant in the present invention may be a flame retardant conventional in the art, such as phosphorus-based flame retardants including alkyl and aryl phosphates, polyphosphates, and the like; nitrogen and phosphorus flame retardants including phosphorus cyanide, phosphorus oxychloride, thiophosphoryl phosphoramide, and the like; and silicon-based flame retardants including silicates, polysilicates, and the like.

Preferably, the flame retardant is a dithiophosphate flame retardant.

The preferred flame retardant can impart higher flame retardant performance to the viscose.

The invention also provides a preparation method of the flame-retardant microcapsule, which at least comprises the following steps:

step one, weighing each component according to a design ratio, and dissolving the weighed gelatin and hemicellulose in water to obtain a wall material solution;

dissolving the weighed flame retardant in water, adding a dispersing agent and an emulsifying agent, and uniformly mixing to obtain a core material emulsion;

and step three, uniformly mixing the wall material solution and the core material emulsion, adjusting the pH value to 3.4-4.8, adding a curing agent, and curing at 45-65 ℃ for 3-6h to obtain the flame-retardant microcapsule.

Preferably, in the first step, the gelatin mass concentration of the wall material solution is 5.1-5.6 wt%.

Preferably, in the second step, the mass ratio of the flame retardant to the water is 1: 9-12.

Preferably, in the second step, the dispersant is sorbitan fatty acid ester.

Preferably, the dispersant is span 80.

The preferable dispersing agent can improve the dispersibility of the flame retardant in the wall material solution, so that the wall material is favorable for coating the core material, and the micro-degradable capsule with uniform particle size distribution is further favorable for obtaining.

Preferably, the emulsifier is OP-10.

The preferred emulsifiers facilitate the formation of submicron droplets of the flame retardant, resulting in an emulsion with uniform droplet size.

Preferably, the curing agent is formaldehyde solution with mass concentration of 35-40 wt%.

Preferably, the addition amount of the dispersant is 4.5 to 5.5 wt% of the mass of the flame retardant.

Preferably, the addition amount of the emulsifier is 2.8-3.2 wt% of the mass of the flame retardant.

Preferably, the addition amount of the curing agent is 1-1.2 times of the mass of the wall material.

The flame-retardant microcapsule is prepared by coating the flame retardant with the wall material of renewable hemicellulose, the preparation method is simple, the prepared microcapsule is degradable, green and pollution-free, the flame-retardant effect is good, the compatibility of the microcapsule and the viscose fiber is good, the problem that the flame retardant in the flame-retardant viscose fiber is easy to fall off is effectively solved, meanwhile, the problem of recycling of renewable resources is reasonably solved, and the application prospect is wide.

The invention also provides application of any one of the flame-retardant microcapsules in preparation of flame-retardant viscose fibers.

The flame-retardant microcapsule prepared by the invention has small particle size (less than 1 mu m), can meet the requirement of small aperture of actual production equipment of viscose fibers, and has enhanced compatibility and adhesion with the viscose fibers, thereby improving the flame-retardant effect and flame-retardant durability of the flame-retardant viscose fibers.

The addition amount of the flame-retardant microcapsule provided by the invention in the viscose fiber production stock solution is 10-20 wt%.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.