阅读说明：本技术 一种可用于医用粘合剂及敷料的液体天然橡胶及其制备方法与应用 (Liquid natural rubber for medical adhesive and dressing and preparation method and application thereof ) 是由 敖宁建 雷琪琪 李洲 李日旺 张文柠 于 2019-09-12 设计创作，主要内容包括：本发明属于生物材料与医疗器械技术领域,公开了一种可用于医用粘合剂及敷料的液体天然橡胶及其制备方法与应用。其制备方法具体为：(1)将粘土分散水溶液和天然橡胶新鲜胶乳混合均匀后得到粘土/天然胶乳混合液,然后加入冰醋酸,搅拌均匀后得到凝块；(2)将所得凝块压片后进行干燥得到薄片,将所得薄片薄通成薄胶片,将胶片进行微波辐照后再进行塑炼；(3)将所得塑炼后的胶片在苯/甲苯/丙酮混合溶液中溶解后,除去粘土和溶剂后得到呈现粘稠液体状态的液体天然橡胶。本发明制备过程简单,没有化学品残留,使用的溶剂可以完全回收,得到的液体天然橡胶纯度高,生物相容性好,可以用于医学粘合剂及医用敷料等医疗器械领域。(The invention belongs to the technical field of biological materials and medical instruments, and discloses liquid natural rubber for medical adhesives and dressings, and a preparation method and application thereof. The preparation method specifically comprises the following steps: (1) uniformly mixing the clay dispersed aqueous solution and the natural rubber fresh latex to obtain a clay/natural latex mixed solution, then adding glacial acetic acid, and uniformly stirring to obtain a coagulum; (2) tabletting the obtained coagulum, drying to obtain a thin slice, thinly passing the thin slice into a thin film, and plasticating the thin film after microwave irradiation; (3) dissolving the plasticated rubber sheet in a benzene/toluene/acetone mixed solution, and removing clay and solvent to obtain the liquid natural rubber in a viscous liquid state. The preparation method has the advantages of simple preparation process, no chemical residue, complete recovery of the used solvent, high purity of the obtained liquid natural rubber and good biocompatibility, and can be used in the field of medical instruments such as medical adhesives and medical dressings.)

1. A preparation method of liquid natural rubber for medical adhesives and dressings is characterized by comprising the following steps:

(1) uniformly mixing the clay dispersed aqueous solution and the natural rubber fresh latex to obtain a clay/natural latex mixed solution, then adding glacial acetic acid, and uniformly stirring to obtain a coagulum;

(2) tabletting the coagulum obtained in the step (1), drying to obtain a sheet, thinly passing the sheet into a film, and plasticating the film after microwave irradiation;

(3) dissolving the plasticated rubber sheet obtained in the step (2) in a benzene/toluene/acetone mixed solution, removing clay to obtain a liquid rubber solution, and then removing the solvent to obtain the liquid natural rubber.

2. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

the mass fraction of the clay dispersed aqueous solution in the step (1) is 10-30%; the mass fraction of the fresh natural rubber latex is 15-30%;

the mass ratio of the clay dispersed aqueous solution in the step (1) to the fresh natural rubber latex is 26-35: 18-22.

3. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

the volume ratio of the clay/natural latex mixed solution in the step (1) to the glacial acetic acid is 95-99: 1-5.

4. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

the microwave irradiation power in the step (2) is 850-1500W, and the irradiation time is 15-20 min; the plastication time is 10-15 min.

5. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

and (3) drying at the temperature of 60-80 ℃, wherein the water content of the slices is 5-15 wt%.

6. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

benzene in the benzene/toluene/acetone mixed solution in the step (3): toluene: the volume ratio of acetone is 30-40: 35-45: 1 to 15;

the mass ratio of the film in the step (3) to the benzene/toluene/acetone mixed solution is 1: 18-25.

7. The method for preparing liquid natural rubber for medical adhesives and dressings according to claim 1, characterized in that:

the thickness of the slice in the step (2) is 1-1.5 cm;

and (3) the thickness of the film in the step (2) is 0.2-1.0 cm.

8. A liquid natural rubber prepared by the method of any one of claims 1 to 7 and used for medical adhesives and dressings.

9. The liquid natural rubber for medical adhesives and dressings according to claim 8, characterized in that the molecular weight of the liquid natural rubber is 18kDa to 22 kDa.

10. Use of the liquid natural rubber according to claim 8 or 9 for medical adhesives and dressings in medical adhesives and dressings.

Technical Field

The invention belongs to the technical field of biological materials and medical instruments, and particularly relates to liquid natural rubber for medical adhesives and dressings, and a preparation method and application thereof.

Background

The liquid rubber is a high molecular material which has relative molecular mass far less than that of solid rubber, is viscous fluid liquid at room temperature and can freely flow, and a three-dimensional cross-linked reticular structure can be formed through proper chemical reaction, so that the rubber material with physical and mechanical properties similar to those of common vulcanized rubber is obtained. The liquid rubber has different types according to different classification methods, and is divided into diene liquid rubber according to the types of main chains; an olefin liquid rubber; polyurethane-based liquid rubbers; liquid silicone rubber; six kinds of liquid polysulfide rubber and liquid fluorine rubber.

Chinese patent publication CN 1062746 a discloses a method for preparing an adhesive from liquid natural rubber: 100 parts of natural rubber and 3 parts of radical acceptor are simultaneously put into a rubber mixing mill for kneading at the temperature of 130-180 ℃, in the kneading process of the radical formed by the radical acceptor and the natural rubber, under the action of thermal oxidation and machinery, broken rubber molecules are combined with the radical, so that the molecular weight of the natural rubber is controlled within the range of 2000-10000, the product has good fluidity at room temperature, and some polar groups are generated, thereby increasing the binding force of the adhesive and the cloth.

Chinese patent publication CN 101942042 a discloses a method for preparing liquid natural rubber: adding 1 part of free radical initiator and 15-30 parts of carbonyl compound into the purified latex under the water bath condition of 50-80 ℃, and reacting for 20-26 h to prepare liquid natural rubber with different relative molecular weights, wherein the product is viscous yellow liquid with fluidity. The adopted free radical initiator is potassium persulfate, and the carbonyl compound is propionaldehyde.

Chinese patent publication CN 101921348A discloses a method for preparing epoxidized liquid natural rubber: adding strong oxidant periodic acid into the epoxidized natural rubber at the temperature of 30 ℃, and preparing the epoxidized liquid natural rubber by chemical degradation. The product is a viscous bright yellow liquid with fluidity.

In addition, from the research paper of Qin et al, "comparison of the oxidative degradation preparation process of liquid natural rubber", the changes of the molecular structure and molecular weight of liquid natural rubber under the action of several oxidants (Elastomers, 2012, 22 (3): 32-36) are compared

In his research paper, "influencing factors of liquid natural rubber prepared by chemical degradation method" ("synthetic rubber industry", 2009, 32(5): 370-373), Liao Shuangquan et al investigated the influence of total solid mass fraction of latex, reaction temperature, stabilizer peregal-O, etc. by using natural rubber concentrated latex as raw material and phenylhydrazine as catalyst under the condition of thermoxidation to prepare liquid natural rubber by chemical degradation method.

Suzhou shizhong fai et al (Special rubber products, 2000, 21(5):10-14) use a high temperature shearing and peptizer method to prepare liquid natural rubber from natural rubber through a two-roll mill, comprising the following steps: adding a peptizer A on a rubber mixing mill, thinly passing through the rubber mixing mill for six times, then moving the rubber mixing mill to a 160 ℃ high-temperature double-roller rubber mixing mill, plastifying for 30 minutes, shoveling the rubber mixing mill for later use, and dissolving the rubber mixing mill with a solvent to obtain the liquid natural rubber.

The research paper of Lv Fei Jie et al, "research on the structure of liquid natural rubber" ("the Proc. of tropical crops", 1990, 11 (2): 17-25) introduced the preparation of liquid rubber by research on French rubber: diluting the concentrated latex, adding peregal-O stabilizer, adding three times diluted reactant phenylhydrazine for several times, fully stirring, introducing air, and reacting for 24 hours at 70 ℃ to obtain a product with a molecular weight meeting the requirement; then coagulating with 5% acetic acid, soaking the coagulum in water for 24 hr, cleaning, and extracting with acetone to obtain liquid natural rubber.

From the prior liquid natural rubber preparation technology, the preparation methods all have fatal defects: (1) firstly, the adopted main degradation agents have high toxicity or high toxicity (such as phenylhydrazine, nitrobenzene, propionaldehyde, pyridine and the like); (2) high temperature and even high pressure are required to complete the degradation; (3) the obtained product contains the residual of the initiators, the degrading agents and other toxicants which cannot be removed; (4) the prepared liquid natural rubber has quite complex structure, generates active end groups of acid group and ketone group, has poor performance, and is not beneficial to subsequent application; (5) the preparation process is complex, the reaction time is long, the operation is not easy, the degradation rate of the natural rubber cannot be well controlled, the preparation process is not environment-friendly, and the like, and the preparation method is not suitable for industrial production. Therefore, the prior method greatly restricts the application of the liquid natural rubber in industry.

Disclosure of Invention

In order to overcome the disadvantages and shortcomings of the prior art, the invention provides a method for preparing liquid natural rubber which can be used for medical adhesives and dressings.

The invention also aims to provide the liquid natural rubber of the medical adhesive and dressing prepared by the method.

The invention also aims to provide application of the liquid natural rubber of the medical adhesive and the medical dressing in the field of medical devices such as medical adhesives, medical dressings and the like.

The purpose of the invention is realized by the following scheme:

a preparation method of liquid natural rubber for medical adhesives and dressings comprises the following steps:

(1) uniformly mixing the clay dispersed aqueous solution and the natural rubber fresh latex to obtain a clay/natural latex mixed solution, then adding glacial acetic acid, and uniformly stirring to obtain a coagulum;

(2) tabletting the coagulum obtained in the step (1), drying to obtain a sheet, thinly passing the sheet into a film, and plasticating the film after microwave irradiation;

(3) dissolving the plasticated rubber sheet obtained in the step (2) in a benzene/toluene/acetone mixed solution, removing clay to obtain a liquid rubber solution, and then removing the solvent to obtain the liquid natural rubber.

The mass fraction of the clay dispersed aqueous solution in the step (1) is 10-30%, and the mass fraction is preferably 13-15%; the mass fraction of the natural rubber fresh latex is 15-30%, and preferably 28-30%.

The mass ratio of the clay dispersed aqueous solution to the fresh natural rubber latex in the step (1) is 26-35: 18-22;

the volume ratio of the clay/natural latex mixed solution in the step (1) to the glacial acetic acid is 95-99: 1-5;

the thickness of the slice in the step (2) is 1-1.5 cm;

the drying temperature in the step (2) is 60-80 ℃, and the water content of the slices is 5-15 wt%, preferably 8-12 wt%.

The thickness of the film in the step (2) is 0.2-1.0 cm; preferably 0.4-0.6 cm.

The microwave irradiation power in the step (2) is 850-1500W, and the irradiation time is 15-20 min; the plastication time is 10-15 min.

Benzene in the benzene/toluene/acetone mixed solution in the step (3): toluene: the volume ratio of acetone is 30-40: 35-45: 1-15, preferably 40:45: 5.

The mass ratio of the film in the step (3) to the benzene/toluene/acetone mixed solution is 1: 18-25, preferably 1: 20.

The liquid natural rubber of the medical adhesive and dressing prepared by the method. The liquid natural rubber exhibits a light red viscous liquid state and has a molecular weight of 18kDa to 22 kDa.

The liquid natural rubber of the medical adhesive and the dressing is applied to the field of medical instruments such as medical adhesives and medical dressings.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention directly utilizes the fresh latex, omits the procedure of dry rubber mixing, greatly reduces the energy consumption, and has the advancement and superiority of the prior art;

(2) the invention uses microwave irradiation technology, the clay/natural rubber composite material is put into a microwave oven for treatment, and the irradiation effect of microwaves from inside to outside is utilized to enable the valence-variable metal components such as iron, manganese, copper and the like in the clay to fully play a role and generate catalytic cracking reaction on the hydrocarbon molecular chain of rubber;

(3) the preparation process of the invention does not use toxic chemicals and chemical residues, and finally used solvents can be recovered and eliminated in percentage, so that the obtained liquid natural rubber has high purity and good biocompatibility and can be used in the field of medical instruments such as medical adhesives, medical dressings and the like.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.