阅读说明：本技术 一种基于水刺无纺材料的医用口罩材料及其制备方法 (Medical mask material based on spunlace nonwoven material and preparation method thereof ) 是由 施淑波 张芸 刘北壬 张克 于 2020-02-21 设计创作，主要内容包括：本发明公开了一种基于水刺无纺材料的医用口罩材料及其制备方法,包括依次贴合的外防护层、粘合剂层以及经过拒水、拒油、抗血液和抗酒精四抗整理的水刺无纺布层,所述外防护层为PTFE薄膜,所述水刺无纺布层由竹浆纤维和抗菌涤纶纤维制成。制备方法为：水刺无纺布层的制备：将竹浆纤维和涤纶纤维按比例混合后,经梳理、铺网、牵伸后进行高压水刺,然后经过四抗整理后高温烘干并杀菌、分切、收卷得到水刺无纺布层；外防护层覆合：将粘合剂涂覆在水刺无纺布层表面,再覆盖PTFE薄膜,经过加热辊加压复合后多级拉幅定型得最终材料。本发明中的医用口罩材料没有任何轧点,手感柔软且透气性好,佩戴舒适又同时具备良好的防护性。(The invention discloses a medical mask material based on a spunlace nonwoven material and a preparation method thereof. The preparation method comprises the following steps: preparing a spunlace non-woven fabric layer: mixing bamboo pulp fibers and polyester fibers in proportion, carding, lapping, drafting, performing high-pressure spunlace, performing four-resistance finishing, drying at high temperature, sterilizing, slitting and rolling to obtain a spunlace non-woven fabric layer; covering an outer protective layer: and coating the adhesive on the surface of the spunlace non-woven fabric layer, covering a PTFE film, and performing multi-stage tentering and shaping after heating roller pressurization compounding to obtain the final material. The medical mask material provided by the invention has no rolling point, is soft in hand feeling and good in air permeability, is comfortable to wear, and has good protection performance.)

1. The utility model provides a medical gauze mask material based on water thorn non-woven materials, characterized by, including outer inoxidizing coating, the adhesive layer that laminates in proper order and the water thorn non-woven fabrics layer of resisting water, oil repellency, anti blood and anti-alcohol four anti-arrangements, outer inoxidizing coating is the PTFE film, water thorn non-woven fabrics layer is 1 by the mass ratio: (1-2) bamboo pulp fiber and antibacterial polyester fiber, and the surface density is 150-250 g/m ²The thickness of the outer protective layer is 0.01-0.02 mm; the thickness of the adhesive layer is 0.01-0.03 mm; the thickness of the spunlace nonwoven fabric layer is 0.25-0.55 mm.

2. The medical mask material based on the spunlace nonwoven material as claimed in claim 1, wherein the preparation method of the antibacterial polyester fiber comprises the following steps: adding chitosan into 2-3% acetic acid solution, magnetically stirring for 20-30 h, adding silver nitrate, magnetically stirring for 30-40 min in a dark condition, irradiating the solution for 20-30 min by ultraviolet rays to obtain an antibacterial finishing solution, wherein the mass fraction of the chitosan in the antibacterial solution is 2-4%, and the mass fraction of the silver nitrate is 0.6-0.8%; and (3) carrying out antibacterial finishing on the polyester fiber by using an antibacterial finishing solution by adopting a two-dipping and two-rolling method to obtain the antibacterial polyester fiber.

3. The medical mask material based on spunlace nonwoven material as claimed in claim 1, wherein the raw materials of the adhesive layer comprise, in parts by weight: 50-80 parts of an adhesive base body, 20-60 parts of cellulose base water-absorbing and water-retaining agent, 10-20 parts of tackifying resin, 5-20 parts of mineral oil and 1-10 parts of foaming agent.

4. The medical mask material based on the spunlace nonwoven material as claimed in claim 3, wherein the cellulose-based water-absorbing and water-retaining agent is prepared by the following steps: dispersing bamboo pulp fibers in a mixed solution of 6-8 wt% of NaOH solution and 10-12 wt% of urea solution, freezing at the temperature of-20 to-10 ℃ for 1-3 h to obtain a cellulose solution, wherein the mass ratio of the bamboo pulp fibers to the mixed solution is 1: (30-35); adding a chitosan solution with the concentration of 2-4 wt% into the cellulose solution under stirring until the mass ratio of chitosan to bamboo pulp fiber is (1-2): 4; stirring uniformly, and then dropwise adding the mixture into a cellulose solution according to the mass ratio of 1: (30-50) reacting glutaraldehyde solution with the volume fraction of 2-3% for 1-2 h at 70-80 ℃, and washing and drying the product to obtain the water-absorbing and water-retaining agent.

5. The medical mask material based on the spunlace nonwoven material as claimed in claim 3 or 4, wherein the adhesive matrix is a modified polyurethane elastomer, and the preparation method comprises the following steps:

A) activating activated carbon at 90-110 ℃ for 4-5 h, and dispersing the activated carbon in toluene to obtain a dispersion liquid, wherein the ratio of the activated carbon to the toluene is 1g (50-100 m L);

B) dropwise adding 2, 4-toluene diisocyanate and 3-5 drops of dibutyltin dilaurate into the dispersion liquid according to the mass volume ratio of 50g to (1-2 m L) to the active carbon, stirring and reacting for 10-12 h at 80-90 ℃, filtering, washing and drying to obtain surface modified active carbon;

C) Mixing the components in a mass ratio of 1: (130-140): (4-5) mixing the surface modified activated carbon, the dehydrated tetrahydrofuran polyether and 4-4' diphenylmethane diisocyanate, and reacting at 75-85 ℃ for 1.5-2.5 h to obtain a prepolymer;

D) And (3) defoaming the prepolymer in vacuum, and adding the prepolymer in a mass ratio of (5-6): 100, 4-butanediol, stirring uniformly, defoaming in vacuum, pouring into a mold for curing, curing at 100-110 ℃ for 20-30 h, grinding and granulating to obtain the modified polyurethane elastomer.

6. The medical mask material based on the spunlace nonwoven material as claimed in claim 3 or 4, wherein the tackifying resin is one or more of petroleum resin, rosin glyceride, gum rosin and diterpene olefin polymer; the foaming agent is prepared from the following raw materials in a molar ratio of (1.5-2.5): 1 sodium bicarbonate and citric acid.

7. A method for preparing a medical mask material according to any one of claims 1 to 6, comprising the steps of:

(1) Preparing a spunlace non-woven fabric layer: mixing bamboo pulp fibers and antibacterial polyester fibers in proportion, carding, lapping, drafting, performing high-pressure spunlace, performing tetra-antibiotic finishing, drying at high temperature, sterilizing, slitting and rolling to obtain a spunlace non-woven fabric layer;

(2) Preparation of the adhesive: mixing raw materials of the adhesive in proportion, adding the mixture into an internal mixer, and mixing for 1-2 hours at 150-160 ℃ to obtain the adhesive;

(3) Covering an outer protective layer: and coating the prepared adhesive on the surface of the spunlace non-woven fabric layer to form an adhesive layer, covering a PTFE film on the adhesive layer, pressing and compounding by a heating roller, then performing multi-stage tentering and shaping, cooling and rolling to obtain the medical mask material.

8. The method for preparing a medical mask material according to claim 7, wherein the high-pressure spunlace process in the step (1) adopts a multi-stage spunlace process: the primary pressure is 50-150 bar, and the drafting is 90-200%; the secondary pressure is 90-130 bar, and the drafting is 100-150%; the three-stage pressure is 100-180 bar, and the drafting is 100-150%; the four-stage pressure is 100-200 bar, and the drafting is 100-120%; the five-stage pressure is 80-150 bar, and the drafting is 90-120%.

9. The method for preparing a medical mask material according to claim 7 or 8, wherein the finishing method of the tetra-resistant in the step (1) comprises the following steps: the method for finishing the tetra-antibody in the step (1) comprises the following steps: fully soaking the spunlace nonwoven fabric layer in a three-proofing finishing agent, and drying and shaping the spunlace nonwoven fabric layer through three drying ovens after rolling out excessive water, wherein the three drying temperatures are respectively as follows: the temperature of the first oven is 115-125 ℃, the temperature of the second oven is 145-155 ℃, and the temperature of the third oven is 175-185 ℃.

10. The method for preparing a medical mask material according to claim 7, wherein the temperature during the pressure compounding in the step (3) is 150 to 250 ℃, and the pressure is 0.5 to 8 kg; and (3) carrying out five-stage stretching during multi-stage tentering setting, wherein the stretching rate of each stage is 3-5%.

Technical Field

The invention relates to the technical field of medical materials, in particular to a medical mask material based on spunlace nonwoven materials and a preparation method thereof.

Background

The medical mask is a medical protective article and has the effects of resisting liquid, filtering particulate matters, bacteria and the like, and the safety of personnel is ensured. Most of the existing medical masks are made of SMS or SMMS spunbonded nonwoven and melt-blown nonwoven composite PE films or other external protective layers, or are made of PU films or TPU films or other external protective layers by direct spunbonded nonwoven composite. For example, a "dust-proof and antibacterial medical mask" disclosed in chinese patent document, which is under publication No. CN203152562U, has an outer layer of a spun-bonded nonwoven fabric layer, an anion nano nonwoven fabric layer or a silver ion fiber nonwoven fabric layer. The middle layer is a melt-blown non-woven fabric layer or an air purification filter membrane layer. The inner layer is a bamboo fiber non-woven fabric layer or a bamboo fiber textile fabric layer.

However, the traditional medical mask material is poor in wearing comfort, and firstly, the spun-bonded non-woven fabric is made close to the rolling point, so that the hand feeling is relatively hard, and the softness is poor; secondly, because the protection performance and the air permeability and moisture permeability are contradictory, when the film covering material is used for achieving a good protection effect, the situation that a wearer feels stuffy and sweaty cannot be avoided, moisture exhaled by the wearer cannot be effectively discharged, the material with good air permeability and moisture permeability cannot well block blood, alcohol and the like, and the protection effect is poor. Therefore, finding a proper material to enable the medical mask to achieve both protection and comfort is a problem to be solved urgently.

Disclosure of Invention

The invention aims to overcome the defects that the medical mask material in the prior art has hard handfeel and poor softness; the medical mask is made of spunlace non-woven fabrics which are finished by tetra-resistance (water repellency, oil repellency, blood resistance and alcohol resistance) and have antibacterial performance and materials compounded with PTFE films, the spunlace non-woven fabrics do not have any rolling points, are soft in hand feeling and good in air permeability, have good protection performance after the tetra-resistance finishing, and can be compounded with the PTFE films with good protection performance and air permeability to make the medical mask with protection performance and comfort.

In order to achieve the purpose, the invention adopts the following technical scheme:

The utility model provides a medical gauze mask material based on water thorn non-woven materials, includes outer inoxidizing coating, adhesive layer and the water thorn non-woven fabrics layer of refusing water, oil repellency, anti blood and anti-alcohol four anti-finishing that laminate in proper order, outer inoxidizing coating is the PTFE film, water thorn non-woven fabrics layer is 1 by the mass ratio: (1-2) bamboo pulp fiber and antibacterial polyester fiber, and the surface density is 150-250 g/m ²The thickness of the outer protective layer is 0.01-0.02 mm; the thickness of the adhesive layer is 0.01-0.03 mm; the thickness of the spunlace nonwoven fabric layer is 0.25-0.55 mm.

The invention adopts the bamboo pulp fiber and the antibacterial polyester fiber to prepare the spunlace nonwoven fabric, and then the spunlace nonwoven fabric is compounded with PTFE through the adhesive, the impact force of the water jet is utilized in the spunlace process to enable the bamboo pulp fiber and the antibacterial polyester fiber to be mutually entangled and interpenetrated and mixed together to form a firm structure, and the acting force of the water jet does not generate any rolling point, so that the spunlace nonwoven fabric layer has soft hand feeling and good drapability; and the entangled fibers have more pores and good air permeability, so that the human body feels comfortable to wear. However, the effective protection effect cannot be achieved by only using the spunlace nonwoven fabric layer, so that the spunlace nonwoven fabric layer is subjected to water-repellent, oil-repellent, blood-repellent and alcohol-resistant four-component finishing, the spunlace nonwoven fabric layer can block the penetration of liquids such as alcohol and blood, the materials are prevented from being wetted by organic oil pollutants, the materials are prevented from causing adverse effects on precision instruments in operations due to static electricity caused by friction in the using process, and the antibacterial polyester fibers in the spunlace nonwoven fabric layer material have good antibacterial property, and bacteria can be prevented from entering the mouth and nose. Then the spunlace nonwoven fabric layer after the four-resistance finishing is compounded with the PTFE film of the outer protective layer, the PTFE film has good water resistance, oil resistance, alcohol resistance and other protective effects, and bacteria are not easy to survive on the PTFE film, so that the protective capability of the material can be further improved after the composite material is compounded with the PTFE film, and the medical protective requirement can be met; and the PTFE film has small aperture, high aperture ratio, good ventilation effect, uneasy sultriness after long-time wearing and good wearing comfort.

Preferably, the preparation method of the antibacterial polyester fiber comprises the following steps: adding chitosan into 2-3% acetic acid solution, magnetically stirring for 20-30 h, adding silver nitrate, magnetically stirring for 30-40 min in a dark condition, and irradiating the solution for 20-30 min by using ultraviolet rays to obtain an antibacterial finishing solution; and (3) carrying out antibacterial finishing on the polyester fiber by using an antibacterial finishing solution by adopting a two-dipping and two-rolling method to obtain the antibacterial polyester fiber. According to the invention, the chitosan-based silver-loaded antibacterial finishing solution is adopted to carry out antibacterial finishing on the polyester fiber to obtain the antibacterial polyester fiber, and the nano silver can enable the polyester fiber to have good antibacterial performance, so that the prepared medical mask can effectively protect bacteria.

Preferably, the adhesive raw material of the adhesive layer comprises in parts by weight: 50-80 parts of adhesive matrix, 20-60 parts

Cellulose-based water-absorbing and water-retaining agent, 10-20 parts of tackifying resin, 5-20 parts of mineral oil and 1-10 parts of foaming agent.

When the spunlace nonwoven fabric layer obtains good protectiveness after four-resistance arrangement, the water repellency of the spunlace nonwoven fabric layer enables moisture exhaled by a wearer and sweat generated by the wearer to be reserved on one side next to the skin and not easy to be discharged outwards, and the inner layer is easily covered with the moisture and the sweat after the spunlace nonwoven fabric layer is worn for a long time, so that the comfort is affected. Therefore, the cellulose-based water-absorbing and water-retaining agent is added into the adhesive layer, and because cellulose has excellent water-absorbing performance, two sides of the spunlace nonwoven fabric layer have different hydrophilicities, so that the unidirectional moisture-conducting function of the material can be realized. Meanwhile, cellulose is not easy to dissolve after absorbing water and swelling, so the cellulose-based water-absorbing and water-retaining agent also has good water-retaining property, absorbed water can be effectively retained in the cellulose-based water-absorbing and water-retaining agent and stays in the adhesive layer, and the antistatic performance of the protective clothing is further improved. The cellulose-based water-absorbing and water-retaining agent is embedded in the adhesive matrix, and the whole structure of the adhesive layer after the cellulose-based water-absorbing and water-retaining agent absorbs water and swells can be guaranteed not to change under the restriction action of the surrounding adhesive matrix, so that the adhesive effect is not influenced.

If the adhesive matrix is directly laid between the PTFE film and the spunlace nonwoven fabric, the absence of voids in the adhesive matrix impedes the venting of gas, resulting in a reduction in the permeability of the material. Therefore, the foaming agent is added into the adhesive material, so that the adhesive matrix has a porous structure, the air permeability of the whole material can be ensured, the micropores in the adhesive matrix can mechanically absorb liquid, the mechanical absorption speed is higher than that of chemical absorption, the sweat absorption speed is further improved, the contact area of sweat and the adhesive layer is increased due to the microporous structure, the water absorption effect of the adhesive layer is improved, the close-fitting side is ensured to be dry, and the comfort is greatly improved.

Preferably, the preparation method of the cellulose-based water-absorbing and water-retaining agent comprises the following steps: dispersing bamboo pulp fibers in a mixed solution of 6-8 wt% of NaOH solution and 10-12 wt% of urea solution, freezing at the temperature of-20 to-10 ℃ for 1-3 h to obtain a cellulose solution, wherein the mass ratio of the bamboo pulp fibers to the mixed solution is 1: (30-35); adding a chitosan solution with the concentration of 2-4 wt% into the cellulose solution under stirring until the mass ratio of chitosan to bamboo pulp fiber is (1-2): 4; stirring uniformly, and then dropwise adding the mixture into a cellulose solution according to the mass ratio of 1: (30-50) reacting glutaraldehyde solution with the volume fraction of 2-3% for 1-2 h at 70-80 ℃, and washing and drying the product to obtain the water-absorbing and water-retaining agent.

Although cellulose itself has good water-absorbing properties, it is irreversible after swelling upon absorption of water, and is dissolved after swelling to some extent when the amount of absorbed water is large, limiting the amount of water absorption and retention, and affecting the adhesive properties of the adhesive layer. Therefore, the bamboo pulp cellulose obtained from the bamboo pulp fiber and chitosan with excellent water absorption performance are prepared into cellulose-chitosan hydrogel under the action of the cross-linking agent, due to the existence of the cross-linking network, the hydrogel can swell and retain a large amount of water, the swelling process is reversible, the original structure can be restored after water evaporation, and water can be continuously and circularly absorbed, so that when the bamboo pulp cellulose is used as the water absorption and retention agent, the water absorption and retention capacity is obviously improved compared with the water absorption and retention agent when the cellulose and the chitosan are used independently, and the bonding stability of an adhesive layer can also be improved.

And the cellulose-based water-absorbing and water-retaining agent is prepared into a hydrogel structure, and the holes in the three-dimensional net structure can further improve the water absorption speed, so that the water can be more quickly guided into the adhesive layer from the side next to the skin of the spunlace nonwoven fabric layer, and the wearing comfort of a human body is improved.

Preferably, the adhesive matrix is a modified polyurethane elastomer, and the preparation method comprises the following steps:

A) activating activated carbon at 90-110 ℃ for 4-5 h, and dispersing the activated carbon in toluene to obtain a dispersion liquid, wherein the ratio of the activated carbon to the toluene is 1g (50-100 m L);

B) dropwise adding 2, 4-toluene diisocyanate and 3-5 drops of dibutyltin dilaurate into the dispersion liquid according to the mass volume ratio of 50g to (1-2 m L) to the active carbon, stirring and reacting for 10-12 h at 80-90 ℃, filtering, washing and drying to obtain surface modified active carbon;

C) Mixing the components in a mass ratio of 1: (130-140): (4-5) mixing the surface modified activated carbon, the dehydrated tetrahydrofuran polyether and 4-4' diphenylmethane diisocyanate, and reacting at 75-85 ℃ for 1.5-2.5 h to obtain a prepolymer;

D) And (3) defoaming the prepolymer in vacuum, and adding the prepolymer in a mass ratio of (5-6): 100, 4-butanediol, stirring uniformly, defoaming in vacuum, pouring into a mold for curing, curing at 100-110 ℃ for 20-30 h, grinding and granulating to obtain the modified polyurethane elastomer.

The adhesive matrix of the invention adopts modified polyurethane elastomer, and the hot melt adhesive formed by the polyurethane elastomer has excellent cohesiveness, and has the advantages of no solvent pollution, high initial viscosity and the like. When the cellulose-based water-retaining agent is used in a medical mask, a large amount of moisture exhaled by a human body and generated sweat can continuously corrode the cellulose-based water-retaining agent to influence the cohesiveness of the cellulose-based water-retaining agent, the cellulose-based water-retaining agent can swell after absorbing water, the adhesive matrix needs to maintain the whole structure under the expansion and extrusion of the water-retaining agent without changing, and the requirement on the structural stability of the adhesive matrix is high, so that the activated carbon is introduced into the polyurethane elastomer to improve the corrosion resistance and the structural stability of the polyurethane elastomer.

If the activated carbon is directly added into the polyurethane elastomer, the dispersibility of the activated carbon is poor and the activated carbon is easy to agglomerate, so the invention firstly modifies the surface of the activated carbon through the steps A) and B) to obtain the modified isocyanated activated carbon, improves the dispersibility and the compatibility with the polyurethane elastomer, and then adopts an in-situ polymerization method to prepare the modified polyurethane elastomer filled with the nano filler in the steps C) and D), and when the modified polyurethane elastomer is used as an adhesive matrix, the corrosion resistance and the structural stability of the adhesive matrix are effectively improved.

Preferably, the tackifying resin is one or more of petroleum resin, rosin glyceride, gum rosin and diterpene olefin polymer; the foaming agent is prepared from the following raw materials in a molar ratio of (1.5-2.5): 1 sodium bicarbonate and citric acid. The combination of the tackifying resin and the adhesive matrix can improve the bonding performance, so that the spunlace nonwoven fabric layer and the external protective layer are bonded better.

The invention also provides a preparation method of the medical mask material, which comprises the following steps:

(1) Preparing a spunlace non-woven fabric layer: mixing bamboo pulp fibers and antibacterial polyester fibers in proportion, carding, lapping, drafting, performing high-pressure spunlace, performing tetra-antibiotic finishing, drying at high temperature, sterilizing, slitting and rolling to obtain a spunlace non-woven fabric layer;

(2) Preparation of the adhesive: mixing raw materials of the adhesive in proportion, adding the mixture into an internal mixer, and mixing for 1-2 hours at 150-160 ℃ to obtain the adhesive;

(3) Covering an outer protective layer: and coating the prepared adhesive on the surface of the spunlace non-woven fabric layer to form an adhesive layer, covering a PTFE film on the adhesive layer, pressing and compounding by a heating roller, then performing multi-stage tentering and shaping, cooling and rolling to obtain the medical mask material.

Preferably, the high-pressure spunlace process in the step (1) adopts a multi-stage spunlace process: the primary pressure is 50-150 bar, and the drafting is 90-200%; the secondary pressure is 90-130 bar, and the drafting is 100-150%; the three-stage pressure is 100-180 bar, and the drafting is 100-150%; the four-stage pressure is 100-200 bar, and the drafting is 100-120%; the five-stage pressure is 80-150 bar, and the drafting is 90-120%. By adopting the multi-stage high-pressure spunlace process and parameters, the bamboo pulp fibers and the polyester fibers can be better entangled, and the prepared spunlace nonwoven fabric layer has good pores, so that the prepared spunlace nonwoven fabric layer has enough strength and good air permeability.

Preferably, the method for finishing the tetrazine in the step (1) is as follows: fully soaking the spunlace nonwoven fabric layer in a three-proofing finishing agent, and drying and shaping the spunlace nonwoven fabric layer through three drying ovens after rolling out excessive water, wherein the three drying temperatures are respectively as follows: the temperature of the first oven is 115-125 ℃, the temperature of the second oven is 145-155 ℃, and the temperature of the third oven is 175-185 ℃.

Preferably, the temperature during the pressure compounding in the step (3) is 150-250 ℃, and the pressure is 0.5-8 kg; and (3) carrying out five-stage stretching during multi-stage tentering setting, wherein the stretching rate of each stage is 3-5%. Because the tension ratio of the film covering processing is larger, the spunlace non-woven fabric is difficult to avoid the situation of width shrinkage, so the multi-stage tentering process adopted by the invention can ensure the width requirement of the finished product and simultaneously does not influence the performance of the finished product.

Therefore, the invention has the following beneficial effects:

(1) The medical mask material made of spunlace non-woven fabrics based on bamboo pulp fibers and antibacterial polyester fibers is soft in hand feeling and good in drapability; the pores are more, the air permeability is good, and the wearing of the human body is comfortable; the polyester fiber is subjected to antibacterial finishing, the spunlace non-woven fabric layer is subjected to tetra-antibacterial finishing and is compounded with the PTFE film, so that the protective performance is good;

(2) The adhesive layer is made of an adhesive matrix and a cellulose-based water-absorbing and water-retaining agent, the adhesive layer has water-absorbing and water-retaining properties while the adhesiveness is ensured, and two sides of the spunlace nonwoven fabric layer have different hydrophilicities, so that unidirectional moisture conduction is realized, moisture exhaled by a human body and generated sweat can be rapidly transmitted to the adhesive layer, the close-fitting side is ensured to be dry and comfortable, and the antistatic performance of the material can be improved after the adhesive layer absorbs water;

(3) The cellulose-based water-absorbing and water-retaining agent adopts a cellulose-chitosan hydrogel structure, so that the water-absorbing and water-retaining capacity of the cellulose-based water-absorbing and water-retaining agent is improved, the bonding stability of the adhesive layer is ensured, the conduction speed of sweat to the adhesive layer can be accelerated, and the wearing comfort is improved;

(4) The adhesive matrix uses the modified polyurethane elastomer filled with the nano filler, and when the modified polyurethane elastomer is used as the adhesive matrix, the corrosion resistance and the structural stability of the adhesive matrix are effectively improved.

Detailed Description

The invention is further described with reference to specific embodiments.