阅读说明：本技术 一种布料加工用防霉抗菌剂及其制备方法 (Mildew-proof antibacterial agent for cloth processing and preparation method thereof ) 是由 李文功 李�荣 夏明容 于 2021-06-01 设计创作，主要内容包括：本发明涉及布料整理技术领域,具体为一种布料加工用防霉抗菌剂及其制备方法,包括以下重量份原料：改性壳聚糖10-20份、膨润土10-15份、硝酸铜5-12份、纳米氧化钛2-5份、纳米氧化锌3-6份、复合渗透剂1-3份、去离子水200-300份；本发明通过加入膨润土,膨润土和改性壳聚糖复合,使得ZATA电位升高,改性壳聚糖的表面带有更多的正电荷,大量的正电荷与霉菌带负电荷的细胞膜结合,有效的抑制霉菌的繁殖,从而起到良好的防霉抗菌效果；本发明通过加入硝酸铜、纳米氧化钛和纳米氧化锌,纳米氧化钛和纳米氧化锌被吸附在改性壳聚糖内,保证了抗菌性,铜离子替换膨润土中的钠离子和钙离子,有利于铜离子固定在膨润土的骨架中,实现长效的防霉杀菌。(The invention relates to the technical field of cloth finishing, in particular to a mildew-proof antibacterial agent for cloth processing and a preparation method thereof, wherein the mildew-proof antibacterial agent comprises the following raw materials in parts by weight: 10-20 parts of modified chitosan, 10-15 parts of bentonite, 5-12 parts of copper nitrate, 2-5 parts of nano titanium oxide, 3-6 parts of nano zinc oxide, 1-3 parts of a composite penetrating agent and 300 parts of deionized water 200-containing organic solvent; according to the invention, bentonite and modified chitosan are added for compounding, so that ZATA potential is raised, the surface of the modified chitosan is provided with more positive charges, and a large number of positive charges are combined with cell membranes of mould with negative charges, so that the propagation of the mould is effectively inhibited, and a good mould-proof antibacterial effect is achieved; according to the invention, copper nitrate, nano titanium oxide and nano zinc oxide are added, the nano titanium oxide and the nano zinc oxide are adsorbed in the modified chitosan, so that the antibacterial property is ensured, and the copper ions replace sodium ions and calcium ions in bentonite, so that the copper ions are favorably fixed in a framework of the bentonite, and the long-acting mildew-proof sterilization is realized.)

1. The mildew-proof antibacterial agent for processing the cloth is characterized by comprising the following raw materials in parts by weight: 10-20 parts of modified chitosan, 10-15 parts of bentonite, 5-12 parts of copper nitrate, 2-5 parts of nano titanium oxide, 3-6 parts of nano zinc oxide, 1-3 parts of a composite penetrating agent and 300 parts of deionized water.

2. The mildew-proof antibacterial agent for cloth processing according to claim 1, wherein the mildew-proof antibacterial agent comprises 15 parts of modified chitosan, 12 parts of bentonite, 8 parts of copper nitrate, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of a composite penetrating agent and 250 parts of deionized water.

3. The mildew-proof antibacterial agent for cloth processing according to claim 1, wherein the composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene ether, and the mass ratio of the sodium dodecyl benzene sulfonate to the alkylphenol polyoxyethylene ether is 2: 1 and mixing.

4. The mold and bacteria inhibitor for processing cloth according to claim 1, wherein the particle size of the nano titanium oxide and the particle size of the nano zinc oxide are both 80 to 100 nm.

5. The mildew-proof and antibacterial agent for cloth processing as claimed in claim 1, wherein the preparation method of the modified chitosan comprises the following steps:

s1: putting 8-12 parts of chitosan and 10-20 parts of propanol into a reactor, and gradually heating to 75-85 ℃ in the stirring process to obtain a mixture A;

s2: putting 7-10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 10-15 parts of distilled water into a container, and dissolving to obtain a mixture B;

s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6-7h, and filtering, washing, filtering and drying to obtain a crude product;

s4: and (3) soaking the crude product in an ethanol solution, extracting for 18-24 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

6. The mold and bacteria inhibitor for processing cloth according to claim 5, wherein the ethanol solution is used in the step S4 in an amount of 75-85% by weight.

7. The method for preparing the mildew-proof antibacterial agent for the cloth processing according to any one of claims 1-6, which is characterized by comprising the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 1-2h at 50-65 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 60-70 ℃, and slowly stirring for 6-8h to obtain the mildew-proof antibacterial agent for cloth processing.

8. The method according to claim 7, wherein in the step (1), the dilute hydrochloric acid is added to the filtrate obtained by suction filtration, and the suction filtration is stopped until no white precipitate is generated when the dilute hydrochloric acid is added to the last filtrate.

Technical Field

The invention relates to the technical field of cloth finishing, in particular to a mildew-proof antibacterial agent for cloth processing and a preparation method thereof.

Background

The textiles are closely related to the life of people, however, various textiles, particularly cotton fabrics, are especially shaking tables for the growth of microorganisms such as bacteria, fungi and the like, and the excessive growth of the microorganisms can harm the health of human beings and cause various skin diseases, so that the research on the antibacterial property of the textiles is of great significance. The chitosan is deacetylated derivative of chitin, has good biocompatibility, biodegradability, natural nontoxicity and various biological activities, especially spectrum antibacterial property, has high reaction activity due to a plurality of active groups such as amino, hydroxyl and the like on a molecular chain, and is extremely easy to perform complex reaction with transition metal ions.

At present, chitosan is widely concerned as a natural antibacterial agent, but the antibacterial activity of chitosan is lower than that of the traditional antibacterial agent, and the chitosan is not enough to be widely applied to the textile industry. Therefore, we propose a mildew-proof antibacterial agent for cloth processing and a preparation method thereof to solve the above problems.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a mildew-proof antibacterial agent for processing cloth and a preparation method thereof, so as to overcome the problems mentioned in the background technology.

In order to achieve the above purpose, the technical scheme of the invention is realized by the following technical scheme: the mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 10-20 parts of modified chitosan, 10-15 parts of bentonite, 5-12 parts of copper nitrate, 2-5 parts of nano titanium oxide, 3-6 parts of nano zinc oxide, 1-3 parts of a composite penetrating agent and 300 parts of deionized water.

Preferably, 15 parts of modified chitosan, 12 parts of bentonite, 8 parts of copper nitrate, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of a composite penetrating agent and 250 parts of deionized water.

Preferably, the composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene ether, and the mass ratio of the sodium dodecyl benzene sulfonate to the alkylphenol polyoxyethylene ether is 2: 1 and mixing.

Preferably, the particle size of the nano titanium oxide and the particle size of the nano zinc oxide are both 80-100 nm.

Preferably, the preparation method of the modified chitosan comprises the following steps:

s1: putting 8-12 parts of chitosan and 10-20 parts of propanol into a reactor, and gradually heating to 75-85 ℃ in the stirring process to obtain a mixture A;

s2: putting 7-10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 10-15 parts of distilled water into a container, and dissolving to obtain a mixture B;

s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6-7h, and filtering, washing, filtering and drying to obtain a crude product;

s4: and (3) soaking the crude product in an ethanol solution, extracting for 18-24 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

Preferably, in step S4, the ethanol solution has a mass fraction of 75-85%.

The invention also provides a preparation method of the mildew-proof antibacterial agent for cloth processing, which comprises the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 1-2h at 50-65 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 60-70 ℃, and slowly stirring for 6-8h to obtain the mildew-proof antibacterial agent for cloth processing.

Preferably, in step (1), dilute hydrochloric acid is added to the filtrate obtained by suction filtration, and the suction filtration is stopped until no white precipitate is generated when dilute hydrochloric acid is added to the last filtrate.

The invention has the beneficial effects that:

according to the invention, the modified chitosan is added, and the chitosan can obtain good solubility and antibacterial effect only under an acidic condition, so that the application of the chitosan in the cloth mildew preventive is limited, and as the surface of the chitosan has a large number of amino groups, 2, 3-epoxypropyltrimethylammonium chloride is added, and active groups are introduced on N or O of the molecular structure of the chitosan, the water capacity of the prepared modified chitosan is improved, and the antibacterial performance is also improved;

according to the invention, bentonite and modified chitosan are added for compounding, so that ZATA potential is raised, the surface of the modified chitosan is provided with more positive charges, and a large number of positive charges are combined with cell membranes of mould with negative charges, so that the propagation of the mould is effectively inhibited, and a good mould-proof antibacterial effect is achieved;

according to the invention, the copper nitrate, the nano titanium oxide and the nano zinc oxide are added, wherein the nano titanium oxide and the nano zinc oxide are adsorbed in the modified chitosan, so that the agglomeration of the nano titanium oxide and the nano zinc oxide is effectively prevented, the antibacterial property is ensured, meanwhile, the copper nitrate is inserted into the bentonite, and the copper ions replace sodium ions and calcium ions in the bentonite, so that the copper ions are favorably fixed in a framework of the bentonite, and the long-acting mildew-proof sterilization is realized.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 10 parts of modified chitosan, 10 parts of bentonite, 5 parts of copper nitrate, 2 parts of nano titanium oxide, 3 parts of nano zinc oxide, 1 part of composite penetrating agent and 200 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the modified chitosan comprises the following steps: s1: placing 12 parts of chitosan and 15 parts of propanol into a reactor, and gradually heating to 80 ℃ in the stirring process to obtain a mixture A; s2: putting 10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 15 parts of distilled water into a container, and dissolving to obtain a mixture B; s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6 hours, and filtering, washing, filtering and drying to obtain a crude product; s4: and (3) soaking the crude product in an ethanol solution with the mass fraction of 80%, extracting for 20 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 1h at 50 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 60 ℃, and slowly stirring for 6 hours to obtain the mildew-proof antibacterial agent for cloth processing.

In the step (1), dilute hydrochloric acid is added into the filtrate obtained by suction filtration until no white precipitate is generated when the dilute hydrochloric acid is added into the last filtrate, and the suction filtration is stopped.

Example 2

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 15 parts of modified chitosan, 12 parts of bentonite, 8 parts of copper nitrate, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of a composite penetrating agent and 250 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the modified chitosan comprises the following steps: s1: placing 12 parts of chitosan and 15 parts of propanol into a reactor, and gradually heating to 80 ℃ in the stirring process to obtain a mixture A; s2: putting 10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 15 parts of distilled water into a container, and dissolving to obtain a mixture B; s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6 hours, and filtering, washing, filtering and drying to obtain a crude product; s4: and (3) soaking the crude product in an ethanol solution with the mass fraction of 80%, extracting for 20 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 1.5h at 60 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 65 ℃, and slowly stirring for 7 hours to obtain the mildew-proof antibacterial agent for cloth processing.

In the step (1), dilute hydrochloric acid is added into the filtrate obtained by suction filtration until no white precipitate is generated when the dilute hydrochloric acid is added into the last filtrate, and the suction filtration is stopped.

Example 3

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 20 parts of modified chitosan, 15 parts of bentonite, 12 parts of copper nitrate, 5 parts of nano titanium oxide, 6 parts of nano zinc oxide, 3 parts of a composite penetrating agent and 300 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the modified chitosan comprises the following steps: s1: placing 12 parts of chitosan and 15 parts of propanol into a reactor, and gradually heating to 80 ℃ in the stirring process to obtain a mixture A; s2: putting 10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 15 parts of distilled water into a container, and dissolving to obtain a mixture B; s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6 hours, and filtering, washing, filtering and drying to obtain a crude product; s4: and (3) soaking the crude product in an ethanol solution with the mass fraction of 80%, extracting for 20 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 2h at 65 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 70 ℃, and slowly stirring for 8 hours to obtain the mildew-proof antibacterial agent for cloth processing.

In the step (1), dilute hydrochloric acid is added into the filtrate obtained by suction filtration until no white precipitate is generated when the dilute hydrochloric acid is added into the last filtrate, and the suction filtration is stopped.

Comparative example 1

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 15 parts of chitosan, 12 parts of bentonite, 8 parts of copper nitrate, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of a composite penetrating agent and 250 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) placing bentonite, 20% deionized water and copper nitrate into an electric heating stirrer, stirring for 2h at 65 ℃, and performing suction filtration and drying to obtain modified bentonite;

(2) putting chitosan, 20% deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated chitosan solution;

(3) dispersing the modified bentonite in the residual 60% of deionized water to obtain a suspension, slowly adding a pretreated chitosan solution into the suspension at 70 ℃, and slowly stirring for 8 hours to obtain the mildew-proof antibacterial agent for cloth processing.

In the step (1), dilute hydrochloric acid is added into the filtrate obtained by suction filtration until no white precipitate is generated when the dilute hydrochloric acid is added into the last filtrate, and the suction filtration is stopped.

Comparative example 2

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 15 parts of modified chitosan, 12 parts of bentonite, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of a composite penetrating agent and 250 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the modified chitosan comprises the following steps: s1: placing 12 parts of chitosan and 15 parts of propanol into a reactor, and gradually heating to 80 ℃ in the stirring process to obtain a mixture A; s2: putting 10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 15 parts of distilled water into a container, and dissolving to obtain a mixture B; s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6 hours, and filtering, washing, filtering and drying to obtain a crude product; s4: and (3) soaking the crude product in an ethanol solution with the mass fraction of 80%, extracting for 20 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) putting the modified chitosan, 20% of deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(2) and dispersing bentonite into the rest 80% of deionized water to obtain a suspension, slowly adding a pretreated modified chitosan solution and a composite penetrant into the suspension at 70 ℃, and slowly stirring for 8 hours to obtain the mildew-proof antibacterial agent for cloth processing.

Comparative example 3

The mildew-proof antibacterial agent for processing the cloth comprises the following raw materials in parts by weight: 15 parts of modified chitosan, 3 parts of nano titanium oxide, 4 parts of nano zinc oxide, 2 parts of composite penetrant and 250 parts of deionized water.

The composite penetrant comprises sodium dodecyl benzene sulfonate and alkylphenol polyoxyethylene, wherein the sodium dodecyl benzene sulfonate and the alkylphenol polyoxyethylene are mixed according to the mass ratio of 2: 1, mixing; the grain diameters of the nano titanium oxide and the nano zinc oxide are both 80-100 nm.

The preparation method of the modified chitosan comprises the following steps: s1: placing 12 parts of chitosan and 15 parts of propanol into a reactor, and gradually heating to 80 ℃ in the stirring process to obtain a mixture A; s2: putting 10 parts of 2, 3-epoxypropyltrimethylammonium chloride and 15 parts of distilled water into a container, and dissolving to obtain a mixture B; s3: adding the mixture B into a reactor, mixing with the mixture A, reacting for 6 hours, and filtering, washing, filtering and drying to obtain a crude product; s4: and (3) soaking the crude product in an ethanol solution with the mass fraction of 80%, extracting for 20 hours by using a Soxhlet extractor, and drying to obtain the modified chitosan.

The preparation method of the mildew-proof antibacterial agent for processing the cloth comprises the following steps:

(1) putting the modified chitosan, deionized water, nano titanium oxide and nano zinc oxide into a stirrer, and uniformly stirring to obtain a pretreated modified chitosan solution;

(2) and adding the composite penetrating agent into the pretreated modified chitosan solution, and stirring to obtain the mildew-proof antibacterial agent for cloth processing.

Performance detection

The test method comprises the following steps: a plurality of cloths were immersed in the antifungal/antibacterial agents of examples 1 to 3 and comparative examples 1 to 3, respectively, and dipped and rolled twice. According to the evaluation standard of the antibacterial performance of GB/T20944 textiles, antibacterial performance experiments are carried out on the cloth treated by the mildew-proof antibacterial agent in the examples 1-3 and the comparative examples 1-3. Specific detection results are shown in table 1.

TABLE 1 antimildew and antibacterial Properties

As can be seen from Table 1, the fabrics treated with the antifungal/antibacterial agents of examples 1 to 3 exhibited excellent sterilizing effects; in the comparative example 1, chitosan is not modified, and the killing rate of the three bacteria is obviously reduced; compared with the examples, the killing rate of the comparative example 3 is a little worse, which shows that the sterilization effect of the cloth material can be improved by compounding the bentonite and the modified chitosan, and the mildew-proof antibacterial performance of the cloth material can be improved by adding the surface copper nitrate, which is a little worse than the killing rate of the comparative example 2.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.