CN102585273B - Preparation method of high-expansion liquid absorption sponge - Google Patents

Abstract

The invention discloses a preparation method of a high-expansion liquid-absorbing sponge, which belongs to the field of preparation of biomedical materials. In the present invention, the final product is obtained by mixing two polyvinyl formal reaction liquids with different reaction degrees, continuing to react, and going through the steps of pouring, solidification, demoulding, cleaning and the like. The present invention utilizes polyvinyl formal with high pre-reaction depth as the pore core to prepare the sponge material. The material has the characteristics of regular pore structure, no foreign matter residue, soft texture, and immediately expands when it meets water. It is suitable for blood-absorbing surgery in the medical field. , Liquid absorption and other purposes.

Description

A kind of preparation method of high-expansion liquid-absorbing sponge

technical field

The invention belongs to the field of biomedical materials, and relates to a preparation method of a high-expansion liquid-absorbing sponge.

Background technique

Traditional medical cotton gauze is often used in surgical operations. Because of its limited liquid absorption and slow liquid absorption speed, especially the risk of chipping, it is limited in clinical application. As an upgraded substitute for traditional medical cotton yarn, high-expansion medical sponges have been widely used in western developed countries. The typical product comes from American merocel company. Its material is polyvinyl alcohol (PVA) sponge, which has good biocompatibility. It has many advantages such as fast liquid absorption speed and large liquid absorption volume, stable structure without chipping, soft material, comfortable touch, etc. It can be used for postoperative sinus packing, blood absorption and drainage in ophthalmic surgery, neurosurgery and negative pressure drainage trauma treatment, etc.

The most classic PVA sponge production technology is the starch pore-forming method. The method is to add starch to the reaction solution of polyvinyl alcohol solution, formaldehyde and inorganic acid. The starch expands and disintegrates during the cross-linking and curing process of polyvinyl formal. Pores are formed in the positions occupied by it, and the spongy body is obtained after washing away disintegration and other substances. Usually, the starch residue is difficult to wash thoroughly, and the sponge body is easy to mold in wet conditions. The requirements for medical sponges are very strict, so generally this method cannot be used for production.

Introducing gas for foaming is another method for preparing PVA sponges. As patent CN94102999.9 discloses a polyvinyl alcohol foaming material for medical hygiene and its preparation method, sodium bicarbonate is used as foaming agent, but it does not The properties and structural parameters of the obtained materials are provided. Using the foaming principle of surfactants to prepare PVA sponge is another way of gas foaming method. It relies on mechanical stirring to blow air into it to form a certain degree of stable foam under the action of surfactants. Patent CN101613512A discloses a liquid-absorbing foam material and its preparation method. The surfactants used are polyoxyethylene behenitol monolaurate and sodium lauryl sulfate. For foaming in the aqueous reaction solution, attention should be paid to the stability of the foam. At this time, it is very difficult to control the uniformity of the cells, and its implementation has certain limitations.

Contents of the invention

The purpose of the present invention is to aim at providing a kind of novel clean production method that does not need starch porogen, does not foam through gas or surfactant and prepares PVA high-expansion liquid-absorbent sponge. It is characterized in that the mixed reaction solution of polyvinyl alcohol aqueous solution, formaldehyde and inorganic acid with different degrees of acetalization is mixed in a certain proportion and then reacted continuously; the pore size and softness of the material can be adjusted by changing the relative addition amount of the two materials sex. After the sponge prepared by this method is dried and compressed to about 20% of its volume, it can expand and soften within 1 second when it meets physiological saline at 25°C.

Different from previous methods for preparing PVA sponges or porous materials, the present invention utilizes its own materials to form pores in the reaction process. In essence, polyvinyl formal with a higher pre-reaction depth is used as a pore-forming agent for PVA sponges. In the subsequent reaction process of mixing the two liquids, due to the difference in the degree of reaction, the polyvinyl formal with a higher pre-reaction depth is preferentially phase-separated and precipitated from the aqueous solution, which acts as a pore-forming core in the entire material. effect.

The preparation method of the present invention is characterized by comprising the following steps.

(1) Completely dissolve PVA-1799 in water at a temperature above 80°C, then add hydrochloric acid and formaldehyde at a temperature of 40-70°C, and react for 20-60 minutes to obtain material liquid A. The weight percentage of each raw material is: 4-12% of PVA-1799, 2-10% of hydrochloric acid, 2-12% of formaldehyde, and the balance is water.

(2) Completely dissolve polyvinyl alcohol resin in water at a temperature above 80°C, then add hydrochloric acid and formaldehyde at a temperature of 40-70°C, and react for 0-20 minutes to obtain material liquid B. The weight percentage of each raw material: PVA-1799 is 4-12%, hydrochloric acid is 2-10%, formaldehyde is 2-12%, and the balance is water.

(3) Mix material liquid A and material liquid B at a weight ratio of 1:5-100, keep the temperature at 40-70°C, and continue stirring for 5-60 minutes.

(4) Pour the material liquid after the reaction in step (3) into a mold, and place it in an oven at 50-70° C. for 10-24 hours. After demoulding and cleaning, a clean sponge body is obtained.

The sponge prepared by the invention has a pore diameter of 0.1-2.0mm, soft texture, and can expand and soften within 1 second when it meets physiological saline solution at 25°C after being dried and compressed to about 20% of its original thickness.

The present invention has the following characteristics.

1. The reaction feed liquid of the present invention is a homogeneous substance with good fluidity and easy pouring, and the obtained PVA sponge product has a uniform pore structure and soft texture. In the preparation process of the gas foaming method, attention should be paid to the stability of the foam, and the cells are uniform Sexual control is also very difficult.

2. Different from the traditional pore-forming process of adding starch, the present invention uses polyvinyl formal, which has been pre-reacted to a certain depth, as the pore-forming agent of the PVA sponge. There is no foreign matter, and the cleaning is simple, which solves the problem that the starch in the previous method is difficult to completely The problem of cleaning from sponges, the resulting sponge products are suitable as medical materials.

The preparation method adopted in the present invention is simple and easy, and the obtained PVA sponge has the characteristics of swelling immediately when it encounters water, soft texture, large liquid absorption capacity, no foreign matter remaining, and no dandruff, etc., and is suitable for surgical blood and liquid absorption in the medical field. .

Detailed ways

The invention will be further illustrated by the following examples.

Example 1.

Add 5g of PVA-1799 and 50g of water into a three-necked flask with stirring, and heat to 85°C until completely dissolved. Then lower the temperature to 60°C, add 15 g of 18% (mass percentage, the same below) hydrochloric acid and 5 g of 37% (mass percentage, the same below) formaldehyde aqueous solution under stirring, and react at 60°C for 50 minutes.

Add 50g of PVA-1799 and 500g of water into another three-neck flask, heat to dissolve until clear, then lower the temperature to 60°C, add 150g of 18% hydrochloric acid and 50g of 37% formaldehyde solution under stirring. Stirring was continued for 2 minutes at 60°C.

The above two liquids were mixed together, and the reaction was continued at 60° C. for 10 minutes.

Pour the reacted material liquid into the mold, place it in an oven at 65°C and keep it warm for 12 hours, then remove the mold and wash it to obtain a clean sponge body, which is frozen below 0°C and cut into samples of specific shapes. It is 8cm long, 2cm wide, and 1.5cm thick.

After the sample was dried, the morphology was observed with an optical microscope, and the results showed that the pore size was between 0.1 and 0.5 mm, and the pore distribution was regular.

The determination of the liquid absorption is carried out by weighing method, and the liquid absorption object is water at 25°C. The liquid absorption volume is calculated according to the following formula:

In the formula, Q is the liquid absorption ratio, m ₁ is the weight of the sponge sample (g) before liquid absorption, and m ₂ is the weight (g) of the sponge sample after liquid absorption.

After measurement, the liquid absorption is 15 times of the sponge body's own weight.

The method of measuring the expansion speed: compress the sample to a thickness of 3mm, insert it into the physiological saline solution at 25°C, keep it for a period of time, then take it out for observation. The results show that the sponge sample can rapidly expand and soften within 1 second, and return to its original wet state.

Example 2.

Add 5g of PVA-1799 and 50g of water into a three-necked flask with stirring, and heat to 85°C until completely dissolved. Then lower the temperature to 60°C, add 15 g of 18% hydrochloric acid and 4.5 g of 37% formaldehyde solution under stirring, and react at 60°C for 50 minutes.

Add 50g of PVA-1799 and 500g of water into another three-neck flask, heat to dissolve until clear, then lower the temperature to 60°C, add 150g of 18% hydrochloric acid and 45g of 37% formaldehyde solution under stirring. Stirring was continued for 10 minutes at 60°C.

The above two liquids were mixed together, and the reaction was continued at 60° C. for 20 minutes.

Pour the reacted material liquid into the mold, place it in an oven at 65°C and keep it warm for 12 hours, then remove the mold and wash it to obtain a clean sponge body, which is frozen below 0°C and cut into samples of specific shapes. It is 8cm long, 2cm wide, and 1.5cm thick.

After the sample was dried, the morphology was observed with an optical microscope, and the results showed that the pore size was between 0.2 and 1.0 mm, and the pore distribution was regular.

It has been measured that its liquid absorption capacity is 15 times the weight of the sponge body itself. After the sponge is compressed to a thickness of 3 mm, it can rapidly expand and soften within 1 second when it meets physiological saline at 25 ° C, and return to its original wet state.

Example 3.

Add 5g of PVA-1799 and 60g of water into a three-necked flask with stirring, and heat to 85°C until completely dissolved. Then lower the temperature to 50°C, add 16 g of 18% hydrochloric acid and 5 g of 37% formaldehyde solution under stirring, and react at 50°C for 50 minutes.

Add 100g of PVA-1799 and 1200g of water into another three-neck flask, heat to dissolve until clear, then lower the temperature to 50°C, add 320g of 18% hydrochloric acid and 100g of 37% formaldehyde solution under stirring. Stirring was continued for 10 minutes at 50°C.

The above two materials were mixed together, and the reaction was continued at 50° C. for 20 minutes.

Pour the reacted material liquid into the mold, put it in an oven and keep it warm at 65°C for 11 hours, then demould and wash to obtain a clean sponge body, which is frozen below 0°C and cut into samples of specific shapes. It is 8cm long, 2cm wide, and 1.5cm thick.

After the sample was dried, the morphology was observed with an optical microscope, and the results showed that the pore size was between 0.5 and 2.0 mm, and the pore distribution was regular.

It has been measured that its liquid absorption capacity is 16 times the weight of the sponge body itself. After the sponge is compressed to a thickness of 3 mm, it can expand and soften rapidly within 1 second when it encounters physiological saline at 25 ° C, and return to its original wet state.

Example 4.

Add 5g of PVA-1799 and 70g of water into a three-necked flask with stirring, and heat to 85°C until completely dissolved. Then lower the temperature to 60°C, add 20 g of 18% hydrochloric acid and 6 g of 37% formaldehyde solution under stirring, and react at 60°C for 45 minutes.

Add 200g of PVA-1799 and 2800g of water into another three-necked flask, heat to dissolve until clear, then lower the temperature to 60°C, add 800g of 18% hydrochloric acid and 240g of 37% formaldehyde solution under stirring. Stirring was continued for 6 minutes at 60°C.

The above two liquids were mixed together, and the reaction was continued at 60° C. for 6 minutes.

Pour the reacted material liquid into the mold, place it in an oven at 60°C and keep it warm for 17 hours, then remove the mold and wash it to obtain a clean sponge body, which is frozen below 0°C and cut into samples of specific shapes. It is 8cm long, 2cm wide, and 1.5cm thick.

After the sample was dried, the morphology was observed with an optical microscope, and the results showed that the pore size was between 0.2 and 1.0 mm, and the pore distribution was regular.

It has been measured that its liquid absorption capacity is 19 times the weight of the sponge body itself. After the sponge is compressed to a thickness of 3 mm, it can rapidly expand and soften within 1 second when it encounters physiological saline at 25 ° C, and return to its original wet state.

Claims (1)

1. a preparation method for high expansion liquid absorption sponge, is characterized in that comprising the following steps:

(1) at more than 80 ℃ temperature, PVA-1799 is dissolved in to water completely, then at 40～70 ℃ of temperature, adds hydrochloric acid and formaldehyde, react 20～60 minutes, obtain feed liquid A;

The weight percentage of each raw material is: PVA-1799 is 4 ~ 12%, hydrochloric acid 2 ~ 10%, and formaldehyde 2 ~ 12%, surplus is water;

(2) at more than 80 ℃ temperature, PVA-1799 is dissolved in to water completely, then at 40～70 ℃ of temperature, adds hydrochloric acid and formaldehyde, react 0～20 minute, obtain feed liquid B;

The weight percentage of each raw material: PVA-1799 is 4 ~ 12%, hydrochloric acid 2 ~ 10%, and formaldehyde 2 ~ 12%, surplus is water;

(3) feed liquid A and feed liquid B mix by weight the ratio of 1:10～100, maintain the temperature at 40～70 ℃, continue to stir 5～60 minutes;

(4) the reacted feed liquid of step (3) is poured in mould, be placed in baking oven and be incubated 10～24 hours at 50～70 ℃; Through the demoulding, clean, obtain clean cavernous body.