Processing method of high-strength long-acting antibacterial full-starch medical dressing

Abstract

The invention relates to a high-strength long-acting antibacterial all-starch medical dressing processing method, which comprises: S1, mixing starch, glycerin, a monomer, an initiator and a polyguanidine antibacterial agent according to a certain ratio, and drying; s2, melting, extruding and granulating the material obtained in the step S1 by using a twin-screw extruder to obtain thermoplastic antibacterial starch particles; and S3, carrying out film blowing on the product obtained in the step S2 by using a film blowing machine to obtain the long-acting antibacterial all-starch medical dressing. According to the processing method, the starch is taken as a main body, the antibacterial component, the plasticizer, the monomer and the initiator are firstly subjected to melt blending processing to prepare thermoplastic antibacterial starch particles, and then the thermoplastic antibacterial starch particles are subjected to blow molding or tape casting to prepare the high-strength long-acting antibacterial all-starch medical dressing which has the advantages of long-acting bacteriostasis, degradability, excellent mechanical property, capability of industrial production and the like.

Description

Technical Field

[0001] The invention relates to the field of medical dressings, and in particular to a processing method of a high-strength, long-acting antibacterial full-starch medical dressing. Background Art

[0002] Traditional medical dressings mainly play a simple covering and protection role. With the improvement of medical level and the increase in people's demand for health care, modern medical dressings pay more attention to functionality, such as antibacterial, hemostasis, and promotion of wound healing. Effective medical dressings should be non-antigenic and biocompatible, absorb wound fluid and exudate, prevent wound drying and maceration, and protect wounds from infection by inhibiting bacterial growth. Microorganisms such as bacteria are one of the culprits of wound infection. Staphylococcus aureus is a Gram-positive bacterium often found on the skin that can cause a series of skin infections, including folliculitis, furunculosis, and abscesses. In some cases, Staphylococcus aureus can penetrate the skin barrier and cause serious diseases such as pneumonia, meningitis, endocarditis, and sepsis. On the other hand, Escherichia coli is a Gram-negative bacterium that enters the human gastrointestinal tract and causes adverse conditions such as diarrhea. Infection in newborns can cause high fevers and severe cases can lead to coma.

[0003] Starch has the advantages of low cost, wide sources, and good biodegradability. It belongs to a new generation of porous materials and has particular application prospects in wound dressings. Using natural renewable starch as the matrix, when the film material is discarded in the natural environment, it will quickly decompose and convert into harmless substances, and will not pollute the environment. This is in sharp contrast to traditional medical plastic waste and is in line with people's pursuit of sustainable green development. However, the existing starch film materials have poor mechanical properties and are easy to break. They will be contaminated by bacteria and other microorganisms during use. These shortcomings greatly limit the application of starch film materials in the field of medical dressings. In addition, most of the existing all-starch film materials are prepared by the solution film-forming method. This is because starch has poor toughness and is difficult to be directly processed into film materials through industrial molding methods, resulting in the inability to be mass-produced through industrial equipment.

[0004] It can be seen that providing a long-lasting antibacterial full-starch film material that is biodegradable, has good mechanical properties, and can be industrially produced is of great significance in the field of environmental protection and medical dressings. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, the present invention provides a processing method for a high-strength and long-acting antibacterial full-starch medical dressing. The full-starch medical dressing prepared by the invention has the advantages of long-acting antibacterial, biodegradability, excellent mechanical properties and industrial production.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A method for processing a high-strength, long-acting antibacterial full-starch medical dressing comprises the following steps:

[0008] S1: starch, glycerol, monomer, initiator and polyguanidine antibacterial agent are mixed in a certain proportion and dried at 80°C; wherein the weight proportions of the raw materials are 50-70 parts, 30-50 parts, 0-5 parts, 0-1 parts and 0-5 parts respectively;

[0009] S2 uses a twin-screw extruder to melt, extrude and granulate the material obtained in step S1 to obtain thermoplastic antibacterial starch particles; wherein the parameters used for the twin-screw extruder are: the temperature control in the electric heating zone of the barrel is: the temperature of the twin-screw extruder is divided into 10 sections, which are set to 80-90°C, 90-100°C, 110-120°C, 120-130°C, 125-130°C, 125-130°C, 130-135°C, 130-135°C, 135-130°C, 130-125°C; the head temperature is 125-130°C; the screw aspect ratio is 1:40; the screw speed is 150rpm-200rpm;

[0010] S3 uses a film blowing machine to blow film the product obtained in step S2 to obtain a long-acting antibacterial full-starch medical dressing with a thickness of 0.15-0.25 mm; wherein the film blowing process parameters of the film blowing machine are as follows: the temperature of the film blowing machine from the feeder to the mold is divided into 6 sections, which are set to 100℃-110℃, 125℃-135℃, 135℃-140℃, 135℃-140℃, 140℃-135℃, and 135℃-130℃ respectively; the screw speed is 80rpm-100rpm; the screw diameter is 20mm; the screw aspect ratio is 1:28; the film blowing mold diameter is 30mm; the traction speed is 2.5r / min-3.0r / min; and the cooling blast flow rate is 30L / min.

[0011] Preferably, in step S1, the starch used is one of natural corn starch, natural cassava starch, hydroxypropyl starch and hydroxypropyl distarch phosphate.

[0012] Preferably, the antibacterial agent is polyhexamethyleneguanidine hydrochloride or polyhexamethylene biguanide hydrochloride.

[0013] Preferably, the monomer is glycidyl acrylate or glycidyl methacrylate.

[0014] Preferably, the initiator is one of dibenzoyl oxide, potassium persulfate, ammonium persulfate, and azobisisobutyronitrile.

[0015] The present invention adopts the above structure, and has the advantages of:

[0016] 1. The processing method of the present invention uses starch as the main body, and antibacterial components, plasticizers, monomers, and initiators are first melt-blended to prepare thermoplastic antibacterial starch particles, and then blow-molded or cast to obtain high-strength and long-acting antibacterial full-starch medical dressings, which have the advantages of long-acting antibacterial, degradability, excellent mechanical properties, and industrial production.

[0017] 2. The present invention increases the melt strength by grafting the monomer glycidyl methacrylate (GMA), improves the blow molding processing performance of starch, and makes it more suitable for industrial mass production. The hydrophobic multifunctional monomer GMA is polymerized to increase the molecular weight of starch. The monomer undergoes a ring-opening reaction with the hydrophilic hydroxyl group in the starch, and the degree of starch cross-linking is adjusted to obtain materials with different mechanical properties. The increase in polymer molecular weight simultaneously improves the water resistance of the film material. At the same time, the antibacterial agent polyhexamethylene guanidine hydrochloride (PHMG) is chemically immobilized on the starch matrix by a ring-opening reaction with the monomer, and the phenomenon of antibacterial agent migration and leaching to reduce the effective ingredients will not occur, giving the material a long-term antibacterial effect (after immersion in water for 7 days, the antibacterial rate still reaches more than 95%), which is beneficial to food preservation and broadens the application field of starch materials. The film material is degraded in soil for 7 days, and the degradation rate is as high as 90%.

[0018] 3. Through the processing method of the present invention, the output of high-strength and long-acting antibacterial full-starch medical dressing can be as high as 50kg / hour. Not only is the processing technology simple and easy to operate; the present invention is blow-molded from commercially available starch after cross-linking and plasticization, and can be easily decomposed into carbon dioxide and water by microorganisms after being discarded, without polluting the environment; more importantly, starch is a renewable resource that is inexhaustible and meets the requirements of sustainable green development. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the blow molding process using a film blowing machine in the present invention;

[0020] Figure 2 The mechanical properties test results of the full starch medical dressings corresponding to Examples 1-4 of the present invention;

[0021] Figure 3 These are the antibacterial test results of the full-starch medical dressings corresponding to Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0022] In order to clearly illustrate the technical features of the present solution, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0023] 1. Equipment and raw materials

[0024] (1) Equipment: twin-screw extruder, film blowing machine.

[0025] (2) Raw materials: Hydroxypropyl distarch phosphate is a commercially available product (hydroxypropyl substitution degree is 3.1%, amylose content is 23wt%, and amylopectin content is 77%); polyhexamethyleneguanidine hydrochloride is a commercially available product (molecular weight is 1000 g / mol, purity is 99%); glycidyl methacrylate, glycerol and benzoyl peroxide are all of reagent grade.

[0026] 2. Preparation of high-strength and long-lasting antibacterial full-starch medical dressing

[0027] (1) The preparation method is as follows:

[0028] S1: starch, glycerol, monomer, initiator and polyguanidine antibacterial agent are mixed in a certain proportion and dried at 80°C for 24 hours; wherein the weight proportions of the raw materials are 50-70 parts, 30-50 parts, 0-5 parts, 0-1 parts and 0-5 parts respectively;

[0029] S2 uses a twin-screw extruder to melt, extrude and granulate the material obtained in step S1 to obtain thermoplastic antibacterial starch particles; wherein the parameters used for the twin-screw extruder are: the temperature control in the electric heating zone of the barrel is: the temperature of the twin-screw extruder is divided into 10 sections, which are set to 80-90°C, 90-100°C, 110-120°C, 120-130°C, 125-130°C, 125-130°C, 130-135°C, 130-135°C, 135-130°C, 130-125°C; the head temperature is 125-130°C; the screw aspect ratio is 1:40; the screw speed is 150rpm-200rpm;

[0030] S3 uses a film blowing machine to blow a film of the product obtained in step S2 to obtain a long-lasting antibacterial full-starch medical dressing with a thickness of 0.15-0.25 mm; wherein the film blowing process parameters of the film blowing machine are as follows: the temperature of the film blowing machine from the feeder to the mold is divided into 6 sections, which are set in sequence as follows:

[0031] S3 uses a film blowing machine to blow film the product obtained in step S2 to obtain a long-acting antibacterial full-starch medical dressing; wherein the film blowing process parameters of the film blowing machine are as follows: the temperature of the film blowing machine from the feeder to the mold is divided into 6 sections, which are set to 100℃-110℃, 125℃-135℃, 135℃-140℃, 135℃-140℃, 140℃-135℃, 135℃-130℃ in sequence; the screw speed is 80rpm-100rpm; the screw diameter is 20mm; the screw aspect ratio is 1:28; the film blowing mold diameter is 30mm; the traction speed is 2.5r / min-3.0r / min; the cooling blast flow rate is 30L / min. The extrusion-blowing process of the obtained film material sample remains continuous and stable.

[0032] According to the above method, the full starch medical dressings with the raw material composition of Examples 1-4 in Table 1 were prepared respectively, and the obtained film materials were as follows: Figure 1 As shown, the average thickness is 0.20 mm.

[0033] Table 1 Raw material composition of Examples 1-4

[0034]

[0035] 3. Result test

[0036] The hydrophilicity, breaking strength, breaking elongation, antibacterial rate and degradation rate of the all-starch medical dressings prepared in Examples 1-4 were tested, and the test data are shown in Table 2. The stress test of the all-starch medical dressings prepared in Examples 1-4 was performed, and the test results are shown in Table 2. Figure 2 The full starch medical dressings prepared in Examples 1-4 were subjected to antibacterial tests against Escherichia coli and Staphylococcus aureus. The experimental results are shown in Figure 3 .

[0037] Among them, the hydrophilicity test refers to the standard GB / T 30693-2014 to determine the water contact angle; the breaking strength and breaking elongation are determined according to the standard GB / T 1040.3-2006; the antibacterial rate is determined according to the standard GB / T21866-2008 after immersion in water for 7 days; the degradation rate is determined according to the standard GB / T 41010-2021 after burial in soil for 7 days.

[0038] Table 2 Performance data results of all-starch medical dressings

[0039]

[0040]

[0041] From the comparison data in Table 2, it can be seen that with the increase of the content of glycidyl methacrylate monomer, the water contact angle gradually increases. This is because the hydrophilicity of starch is much greater than that of the monomer. With the increase of the degree of polymerization, the increase of the molecular weight of the polymer weakens the hydrophilicity of the material. Figure 2 It can be seen that the mechanical properties have also been significantly improved, the degree of crosslinking is increased, the breaking strength is increased, and the corresponding elongation at break is reduced. The breaking strength of Example 3 and Example 4 are both >13.0MPa, and the elongation at break is >433%, which has reached the requirements of polyester biodegradable plastic blow molding film for mechanical properties (GBT 29646-2013, breaking strength ≥13.0MPa, elongation at break ≥200%). The melt strength is increased by GMA grafting, and the blow molding processing performance of starch is improved.

[0042] In the present invention, the polyhexamethyleneguanidine hydrochloride is successfully fixed on the substrate by chemical bonding by means of a ring-opening reaction, which can achieve a long-term antibacterial effect while maintaining its good stability without causing the effective ingredients to be leached and reduced. Figure 3 It can be seen that the antibacterial rate of the material against Staphylococcus aureus and Escherichia coli is over 95%. At the same time, after being buried in the soil for seven days, the degradation rate of the material is over 90%, indicating that the material will not pollute the environment and is in line with people's pursuit of sustainable green development.

[0043] The above specific implementations cannot be used as limitations on the scope of protection of the present invention. For those skilled in the art, any replacement, improvement or change made to the implementations of the present invention falls within the scope of protection of the present invention. The parts not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A method for processing a high-strength, long-acting antibacterial full-starch medical dressing, characterized in that: The steps include: S1: starch, glycerol, monomer, initiator and polyguanidine antibacterial agent are mixed in a certain proportion and dried; wherein the weight proportions of the raw materials are 50-70 parts, 30-50 parts, 0-5 parts, 0-1 parts and 0-5 parts respectively; S2 uses a twin-screw extruder to melt, extrude and granulate the material obtained in step S1 to obtain thermoplastic antibacterial starch particles; wherein the parameters used for the twin-screw extruder are: the temperature control in the electric heating zone of the barrel is: the temperature of the twin-screw extruder is divided into 10 sections, which are set to 80-90°C, 90-100°C, 110-120°C, 120-130°C, 125-130°C, 125-130°C, 130-135°C, 130-135°C, 135-130°C, 130-125°C; the head temperature is 125-130°C; the screw aspect ratio is 1:40; the screw speed is 150rpm-200rpm; S3 uses a film blowing machine to blow film the product obtained in step S2 to obtain a long-acting antibacterial full-starch medical dressing with a thickness of 0.15-0.25 mm; wherein the film blowing process parameters of the film blowing machine are as follows: the temperature of the film blowing machine from the feeder to the mold is divided into 6 sections, which are set to 100℃-110℃, 125℃-135℃, 135℃-140℃, 135℃-140℃, 140℃-135℃, and 135℃-130℃ respectively; the screw speed is 80rpm-100rpm; the screw diameter is 20mm; the screw aspect ratio is 1:28; the film blowing mold diameter is 30mm; the traction speed is 2.5r / min-3.0r / min; and the cooling blast flow rate is 30L / min.

2. The method for processing the high-strength, long-acting antibacterial full-starch medical dressing according to claim 1, characterized in that: In step S1, the starch used is one of natural corn starch, natural cassava starch, hydroxypropyl starch and hydroxypropyl distarch phosphate.

3. The processing method of the high-strength long-acting antibacterial full-starch medical dressing according to claim 1 is characterized in that: The antibacterial agent is polyhexamethyleneguanidine hydrochloride or polyhexamethylene biguanidine hydrochloride.

4. The processing method of the high-strength, long-acting antibacterial full-starch medical dressing according to claim 1 is characterized in that: The monomer is glycidyl acrylate or glycidyl methacrylate.

5. The processing method of the high-strength long-acting antibacterial full-starch medical dressing according to claim 1 is characterized in that: The initiator is one of dibenzoyl oxide, potassium persulfate, ammonium persulfate and azobisisobutyronitrile.

6. The method for processing the high-strength, long-acting antibacterial full-starch medical dressing according to claim 1, characterized in that: In step S3, before the film blowing process, the product obtained in step S2 is dried at 80°C for 12 hours.

7. The method for processing the high-strength, long-acting antibacterial full-starch medical dressing according to claim 1, characterized in that: In step S1, starch, glycerol, monomer, initiator and polyguanidine antibacterial agent are mixed in a certain proportion and dried at 80° C. for 24 hours.

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