Chemically modified seacell fibres, wound dressing made therefrom and preparation method thereof

Abstract

A chemically modified cellulose/alginate co-spun (seacell) fiber, a wound dressing made therefrom and a preparation method thereof. The seacell fiber is subject to a chemical modification through which a hydrophilic carboxymethyl group is introduced into the cellulose structure making the chemically modified seacell fiber more absorbent. The modified cellulose has a degree of substitution of 0.05-0.5; the seacell fiber has a linear density of 0.5-5 dtex and a fiber length of 5-180 mm. The seacell fiber has hygroscopic and gel-forming properties, while retaining its active ingredient of algae particles.

Claims

1. The A chemically modified cellulose/alginate co-spun fiber, wherein a cellulose structure of the chemically modified cellulose/alginate co-spun fiber comprises hydrophilic groups; a degree of substitution of the cellulose structure is 0.05-0.5; a linear density of the chemically modified cellulose/alginate co-spun fiber is 0.5-5 dtex; a length of the chemically modified cellulose/alginate co-spun fiber is 5-180 mm; alginate particles are embedded in the cellulose structure; and the alginate particles disperse in the cellulose structure evenly.

2. The chemically modified cellulose/alginate co-spun fiber according to claim 1, wherein a size of the alginate particles is 1-100 m.

3. The chemically modified cellulose/alginate co-spun fiber according to claim 1, wherein the alginate particles come from red algae or brown algae.

4. The chemically modified cellulose/alginate co-spun fiber according to claim 1, wherein the chemically modified cellulose/alginate co-spun fiber is carboxymethyl cellulose or carboxyethyl cellulose.

5. The chemically modified cellulose/alginate co-spun fiber according to claim 1, wherein the chemically modified cellulose/alginate co-spun fiber turns to gel when contacting an aqueous solution, facilitating release of an active ingredient in the alginate particles.

6. The chemically modified cellulose/alginate co-spun fiber according to claim 5, wherein the active ingredient released from the alginate particles is alginate acid, amino acid, mineral, fat and vitamin.

7. A wound dressing comprising the chemically modified cellulose/alginate co-spun fiber of claim 1.

8. The wound dressing according to claim 7, wherein an absorbency of the wound dressing to a solution A is equal to or greater than 12 g/100 cm.sup.2 and the solution A comprises 8.298 g sodium chloride and 0.368 g anhydrous calcium chloride per liter of pure water.

9. The wound dressing according to claim 7, wherein a wet strength of the wound dressing is equal to or greater than 0.3 N/cm.

10. The wound dressing according to claim 7, wherein the wound dressing comprises an antibacterial agent including silver salt or nano silver or polyhexamethylene guanidine (PHMB).

11. The wound dressing according to claim 7, wherein the wound dressing is manufactured through a weaving process, a knitting process or a non-woven process.

12. A method of manufacturing the chemically modified cellulose/alginate co-spun fiber of claim 1, the method comprises: 1) immersing a cellulose/alginate co-spun fiber into a sodium hydroxide solution with a concentration of 10%-50% by weight at room temperature; a weight ratio between the cellulose/alginate co-spun fiber and the sodium hydroxide solution is 1:7 to 1:10; 2) subjecting the cellulose/alginate co-spun fiber from step 1) to a solution of sodium chloroacetate, sodium hydroxide, water and ethanol, and a concentration of the sodium chloroacetate in the solution is between 18-50% by weight; 3) washing the treated fiber in an acidic solution, and then washing the treated fiber in an ethanol solution containing 0.1-5% Tween 20 by weight; wherein the acidic solution contains 0.5-5% acetic acid, 20-60% water and 35-79.5% ethanol by weight; a weight ratio between the acid solution and the treated fiber is 5:1 to 50:1; and 4) drying the washed fiber at 30-80 C. for 10-60 minutes.

13. The method according to claim 12, wherein the step 2) involves: 21) preheating the solution to 30-50 C. before subjecting the cellulose/alginate co-spun fiber to the heated solution; 22) continuing to heat the solution to the temperature of 40-65 C.; and 23) maintaining the temperature at 45-60 C. until the fiber turns into a gel.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Example 1

(1) (1) 200 g of cellulose/alginate co-spun fibres (purchased from Smartfibres) is placed into 1000 ml 18% by weight of sodium hydroxide for 60 minutes;

(2) (2) The above fibres are taken out of the solution and squeezed, and then immersed into the reacting solution which has been preheated to 41 C. The fibres are kept in the solution for 60 minutes at 50-55 C. The said reacting solution consists of 1000 g sodium chloroacetate, 830 g 30% sodium hydroxide solution, 2000 g ethanol and 2000 g deionized water;

(3) (3) Take the fibres out of the reaction solution, and then place it into the acid solution for washing for 30 minutes. The fibres are washed twice in the solution until its pH value become neutral or a slightly acidic. The said acid solution consists of 500 ml ethanol, 300 ml pure water and 200 ml acid acetic;

(4) (4) Take the fibres out of the washing solution, squeeze and then place it into the washing solution containing the 1000 ml ethanol and 2% by weight of Tween 20;

(5) (5) Place the fibres in the oven and dry out the fibres.

(6) The degree of substitution of the above chemically modified cellulose/alginate co-spun fibres is 0.29.

(7) The linear density of the above cellulose/alginate co-spun fibres is 3 dtex, and the staple length is 50 mm. The above chemically modified cellulose/alginate co-spun fibres are converted into nonwoven pads by a carding and needle punching process. After slitting, cutting, packaging and sterilization, the dressing's absorbency and wet strength is measured as 19 g/100 cm.sup.2 and 0.35 N/cm respectively.

Example 2

(8) (1) At room temperature, 100 g cellulose/alginate co-spun fibres (purchased from Smartfibres) are placed into 600 ml 25% by weight sodium hydroxide solution for 50 minutes;

(9) (2) The above fibers are taken out from the solution and squeezed to remove excessive solution. The fibres are then immersed into the reacting solution which has been preheated to 38 C. The fibres are kept in the solution for 60 minutes at 50-60 C. The said reacting solution consists of 1000 g sodium chloroacetate, 1630 g 30% sodium hydroxide solution, 2500 g ethanol and 1450 g deionized water;

(10) (3) The fibres are taken out of reaction solution, and then placed them into the acid solution for washing for 30 minutes. Repeat the washing twice in this solution until its pH value become neutral or a slightly acidic. The said acid solution consists of 500 ml ethanol, 300 ml pure water and 200 ml acid acetic;

(11) (4) Take the fibres out of the washing solution, squeeze and then place it into the washing solution containing the 600 ml ethanol and 1.5% by weight of Tween 20;

(12) (5) Place the fibres in the oven and dry out the fibres.

(13) The degree of substitution of the above chemically modified cellulose/alginate co-spun fibres is 0.28.

(14) The linear density of the above cellulose/alginate co-spun fibres is 4 dtex, and the staple length is 60 mm. The above chemically modified cellulose/alginate co-spun fibres are converted into nonwoven pads by a carding and needle punching process. After slitting, cutting, packaging and sterilization, the dressing's absorbency and wet strength are measured as 19.5 g/100 cm.sup.2 and 0.40 N/cm respectively.

Example 3

(15) (1) At room temperature, 100 g cellulose/alginate co-spun fibres (purchased from Smartfibres) are placed into 600 ml 25% by weight sodium hydroxide solution for 60 minutes;

(16) (2) The above fibers are taken out from the solution and squeezed to remove excessive solution. The fibres are then immersed into the reacting solution which has been preheated to 43 C. The fibres are kept in the solution for 46 minutes at 50-55 C. The said reacting solution consists of 1000 g sodium chloroacetate, 2500 g 30% sodium hydroxide solution, 2500 g ethanol and 1750 g deionized water;

(17) (3) The fibres are taken out of reaction solution, and then placed them into the acid solution for washing for 60 minutes. Repeat the washing twice in this solution until its pH value become neutral or a slightly acidic. The said acid solution consists of 500 ml ethanol, 300 ml pure water and 200 ml acid acetic;

(18) (4) Take the fibres out of the washing solution, squeeze and then place it into the washing solution containing the 600 ml ethanol and 1.5% by weight of Tween 20;

(19) (5) Place the fibres in the oven and dry out the fibres.

(20) The degree of substitution of the above chemically modified cellulose/alginate co-spun fibres is 0.30.

(21) The linear density of the above cellulose/alginate co-spun fibres is 5 dtex, and the staple length is 50 mm. The above chemically modified cellulose/alginate co-spun fibres are converted into nonwoven pads by a carding and needle punching process. After slitting, cutting, packaging and sterilization, the dressing's absorbency and wet strength are measured as 21 g/100 cm.sup.2 and 0.35 N/cm respectively.

Example 4

(22) The chemically modified cellulose/alginate co-spun staple fibres from example 1 and carboxymethyl cellulose manufactured by Foshan United Medical Technologies Ltd are blended together, then processed by opening, carding, cross-lapping, double needling, and then by slitting, cutting, packaging and sterilization. The dressing's absorbency was measure at 19 g/100 cm.sup.2, and the wet strength at 0.38 N/cm.

Example 5

(23) The chemically modified cellulose/alginate co-spun staple fibres from example 1 and chitosan fibres purchased from Jifa New Material Ltd are blended together, then processed by opening, carding, cross-lapping, double needling, and then slitting, cutting, packaging and sterilization. The absorbency of the dressing is 15 g/100 cm.sup.2, and the wet strength is 0.50 N/cm.

Example 6

(24) The chemically modified cellulose/alginate co-spun staple fibres from example 2 and High M alginate fibres manufactured by Foshan United Medical Technologies Ltd are blended evenly then processed by opening, carding, cross-lapping, double needling, and then by slitting, cutting, packaging and sterilization. The absorbency of the dressing is 14 g/100 cm.sup.2, and the wet strength is 1.30 N/cm.

Example 7

(25) The chemically modified cellulose/alginate co-spun staple fibres from example 2 and M/G type alginate fibres manufactured by Foshan United Medical Technologies are blended evenly for the nonwoven process of opening, carding, lapping, double needling, and then by slitting, cutting, packaging and sterilization. The absorbency is 16 g/100 cm.sup.2, and the wet strength is 1.60 N/cm.

Example 8

(26) The chemically modified cellulose/alginate co-spun staple fibres from example 1, carboxymethyl cellulose manufactured by Foshan United Medical Technologies and chitosan fibres purchased from Jifa New Material Ltd are blended together, followed by opening, carding, cross-lapping, double needling, and then slitting, cutting, packaging and sterilization. The absorbency of the dressing is measured at 21 g/100 cm.sup.2, and the wet strength is 0.85 N/cm.

Example 9

(27) Manufacture Silver Chemically Modified Cellulose/alginate Co-spun Staple Fibres:

(28) (1) Prepare 30 g cellulose/alginate co-spun staple fibres using the process conditions in example 2;

(29) (2) Prepare 300 ml silver nitrate water/ethanol solution containing 5% ethanol and 1 g silver nitrate. Ensure that the silver nitrate is completely dissolved into solution;

(30) (3) Pre-heat the silver solution to 40 C., and then immerse the chemically modified cellulose/alginate co-spun staple fibres into the solution for 5 minutes;

(31) (4) Introduce sodium chloride into the silver solution at the molar ratio to silver nitrate of 1:1, converting the silver nitrate into silver chloride;

(32) (5) The silver chemically modified cellulose/alginate co-spun staple fibres are dried and then packed.

(33) The silver content of the said silver fibres is 1.2%.

Example 10

(34) Manufacture Silver Chemically Modified Cellulose/alginate Co-spun Staple Fibres:

(35) (1) Prepare 30 g cellulose/alginate co-spun staple fibres using the process conditions in example 2;

(36) (2) Prepare 300 ml silver nitrate water/ethanol solution containing 5% ethanol and 1 g silver nitrate. Ensure that the silver nitrate is completely dissolved into solution;

(37) (3) Pre-heat the silver solution to 40 C., and then immerse the chemically modified cellulose/alginate co-spun staple fibres into the solution for 5 minutes;

(38) (4) Introduce Sodium hypochlorite into the silver solution at the molar ratio to silver nitrate of 1:1, converting the silver nitrate into silver hypochlorite;

(39) (5) The silver chemically modified cellulose/alginate co-spun staple fibres are dried and then packed.

(40) The silver content of the said silver fibres is 1.0%.

Example 11

(41) The silver chemically modified cellulose/alginate co-spun staple fibres from example 10, were blended evenly with the M/G alginate fibres manufactured by Foshan United Medical Technologies Ltd, then processed by opening, carding, cross-lapping, double needling, and then by slitting, cutting, packaging and sterilization. The absorbency of this dressing is 14 g/100 cm.sup.2, and wet strength is 1.45 N/cm.

Example 12

(42) The silver chemically modified cellulose/alginate co-spun staple fibres from example 10, was blended evenly with acylated chitosan fibres purchased from Jifa New Material Ltd, then processed by opening, carding, cross-lapping, double needling, and then by slitting, cutting, packaging and sterilization. The absorbency of this dressing is 17 g/100 cm.sup.2, and wet strength is 1.0 N/cm.