阅读说明：本技术 一种卤胺抗菌阻燃剂及其制备方法和应用 (Halamine antibacterial flame retardant and preparation method and application thereof ) 是由 蒋之铭 徐登辉 王士杰 朱平 于 2020-12-11 设计创作，主要内容包括：本发明涉及氯胺类化合物的合计以及抗菌阻燃技术领域,提供了一种卤胺抗菌阻燃剂及其制备方法和应用,以三聚氯氰或三聚氟氰或两者的衍生物、氨水为原料合成具有氨基结构的中间体；然后在缚酸剂的作用下,制得反应型含磷卤胺抗菌阻燃前驱体,最后通过次氯酸钠的作用制得抗菌阻燃剂。在纺织品后整理中的应用：将待处理纺织品浸渍于含上述含磷卤胺抗菌阻燃前驱体的整理液中,通过轧烘焙方法对纺织品进行功能整理,最后在卤化作用下制得抗菌阻燃纺织品。本发明所述的多功能整理剂具有抗菌、阻燃、无污染、低毒、稳定性好等特点,在纺织品中的应用简单、能耗低,可制得高效杀菌和阻燃的纺织品,且对纺织品的损伤小。(The invention relates to the technical field of total chloramines and antibacterial flame retardant, and provides a halamine antibacterial flame retardant, a preparation method and application thereof, wherein cyanuric chloride or cyanuric fluoride or derivatives of cyanuric fluoride and ammonia water are used as raw materials to synthesize an intermediate with an amino structure; then preparing a reactive phosphorus-containing halamine antibacterial flame-retardant precursor under the action of an acid-binding agent, and finally preparing the antibacterial flame retardant under the action of sodium hypochlorite. Use in the after-finishing of textiles: and (3) soaking the textile to be treated in the finishing liquid containing the phosphorus-containing halamine antibacterial flame-retardant precursor, performing functional finishing on the textile by a rolling and baking method, and finally preparing the antibacterial flame-retardant textile under the action of halogenation. The multifunctional finishing agent has the characteristics of antibiosis, flame retardance, no pollution, low toxicity, good stability and the like, is simple to apply to textiles, has low energy consumption, can prepare textiles with high-efficiency sterilization and flame retardance, and has small damage to the textiles.)

1. A halamine antibacterial flame retardant is characterized in that: a compound having the structure of formula (I):

wherein R represents chlorine or bromine;

R₁represents C₁～C₈Alkyl, cycloalkyl, fluoro, chloro, bromo, hydroxy or phosphate;

R₂represents fluorine or chlorine.

2. The method for preparing a halamine antibacterial flame retardant as claimed in claim 1, wherein: placing cyanuric chloride or cyanuric fluoride or derivatives of cyanuric chloride or cyanuric fluoride in water or an organic solvent, then dropwise adding ammonia water, reacting for 1-6 h at 0-5 ℃, finishing the reaction, filtering, purifying and drying to obtain an intermediate, dispersing the intermediate in the organic solvent, slowly dropwise adding a mixed solution of dimethyl phosphite and carbon tetrachloride at 0-30 ℃, dropwise adding an acid-binding agent, continuing to react for 12-18 h at 0-50 ℃, finishing the reaction to obtain a haloamine antibacterial flame-retardant precursor, and finally dissolving the haloamine antibacterial flame-retardant precursor in hypochlorite/trichloroisocyanuric acid with the mass percentage concentration of 1-10% to obtain the haloamine antibacterial flame retardant, wherein one chlorine/fluorine atom of the derivatives of cyanuric chloride or cyanuric fluoride is subjected to C₁-C₈Alkyl, cycloalkyl, methoxy, fluoro/chloro, bromo, hydroxy or phosphate substitution.

3. The method for preparing the halamine antibacterial flame retardant according to claim 2, characterized in that: the organic solvent for dissolving cyanuric chloride or cyanuric fluoride or derivatives thereof and the dispersion intermediate is selected from tetrahydrofuran, chloroform, carbon tetrachloride, ethanol, diethyl ether, acetone and dioxane.

4. The method for preparing the halamine antibacterial flame retardant according to claim 2, characterized in that: the acid-binding agent is one or a mixture of more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine, sodium methoxide and potassium ethoxide.

5. The method for preparing the halamine antibacterial flame retardant according to claim 2, characterized in that: the hypochlorite/trichloroisocyanurates are selected from one or more of sodium hypochlorite, potassium hypochlorite, calcium hypochlorite and trichloroisocyanurates; the pH value of the hypochlorite/trichloroisocyanuric acid salt solution is 7-12, and the effective chlorine content is 0.1-5%.

6. The method for preparing the halamine antibacterial flame retardant according to claim 2, characterized in that: the precursor of the halamine antibacterial flame retardant is a compound with a structure shown in a formula (II):

R₁represents C₁～C₈Alkyl, cycloalkyl, fluoro, chloro, bromo, hydroxy or phosphate;

R₂represents fluorine or chlorine.

7. The use of a haloamine antibacterial flame retardant of claim 6 in antibacterial flame retardant finishing of textiles, wherein: dissolving a halamine antibacterial flame retardant precursor and an alkaline agent in an organic solvent to prepare a finishing liquid with the mass fraction of 25-50%, finishing the textile by adopting the traditional two-dipping and two-rolling method, pre-drying, baking, washing and drying to obtain a flame-retardant textile, finally soaking the dried textile in hypochlorite/trichloroisocyanuric acid with the mass percentage concentration of 1-10%, taking out the cotton fabric after waiting for a period of time, and drying to obtain the halamine antibacterial flame-retardant textile.

8. The use of a haloamine antibacterial flame retardant in textiles as claimed in claim 7, wherein: the organic solvent is one or more of absolute ethyl alcohol, isopropanol, DMF, DMSO, chloroform and carbon tetrachloride.

9. The use of a haloamine antibacterial flame retardant in textiles as claimed in claim 7, wherein: the molar ratio of the addition amount of the alkaline agent to the haloamine antibacterial flame retardant is 2: 1-1: 2, and the alkaline agent is selected from one or a mixture of more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine, sodium methoxide and potassium ethoxide.

10. The use of a haloamine antibacterial flame retardant in textiles as claimed in claim 7, wherein: the active halogen solution comprises hypochlorite, hypobromite and trichloroisocyanate, and the mass percentage concentration of the active halogen solution is 1-10%.

Technical Field

The invention belongs to the technical field of synthesis of halamine compounds and antibacterial flame retardance, and particularly relates to a halamine antibacterial flame retardant, a preparation method thereof and application thereof in antibacterial flame retardance finishing of textiles.

Background

The flammability and easy breeding of bacteria are two common problems of textiles, especially cotton fabrics, which greatly limit the application of the textile and threaten the life safety of human beings. Every year, textile-caused cross infection and fire disasters are countless, which causes huge property loss and a great amount of casualties. Therefore, the development of the cotton fabric with antibacterial and flame-retardant functions has very important significance, and the spreading infection of harmful microorganisms can be effectively reduced and the safety of human life and property can be protected.

At present, the antibacterial flame-retardant composite protection of textiles is mainly realized by the combined use of an antibacterial agent and a flame retardant, and the problems of complex process, unsatisfactory antibacterial flame-retardant effect, poor durability, poor hand feeling, serious strength loss and the like exist, and the development of the antibacterial flame-retardant multifunctional finishing agent is an effective way for solving the problems.

The halamine compound has the characteristics of reproducibility, stability, safety, high efficiency and the like, and the antibacterial agent contains one or more N-X bonds (X is Cl or Br), can be obtained by the halogenation of amines, amides and imides, and is simple and easy to implement. The existence of the oxidative active elements enables the halamine compound to rapidly kill bacteria, fungi and viruses, the active elements lost in the sterilization and water washing processes can be recovered through halogenation, the halation compound has reproducible sterilization performance, the content of the active elements can be controlled through halogenation conditions according to different requirements, and the halation compound has good application prospects in the field of safety and sanitation.

Therefore, the development of the halamine compound with the flame retardant function and the simple and environment-friendly preparation and application method thereof have great significance for the development of multifunctional textiles.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a halamine antibacterial flame retardant and a preparation method and application thereof, wherein a halamine antibacterial structure and a phosphorus-containing flame retardant group are combined through the unique reaction activity and thermal stability of cyanuric chloride to prepare a reactive multifunctional antibacterial flame retardant (multifunctional finishing agent) with quick sterilization and phosphorus-nitrogen synergistic flame retardant performance, the reactive multifunctional antibacterial flame retardant has higher reactivity, can be covalently combined with fibers such as cellulose fibers at lower temperature to obtain durable antibacterial flame retardant textiles, and the finishing method has less influence on the physical and mechanical properties of the textiles.

The invention adopts the following technical scheme:

a preparation method of a halamine antibacterial flame retardant comprises the following steps:

placing cyanuric chloride or cyanuric fluoride or derivatives of cyanuric chloride or cyanuric fluoride in water or an organic solvent, then dropwise adding ammonia water, reacting for 1-6 h at 0-5 ℃, filtering, purifying and drying after the reaction is finished, thus obtaining an intermediate. Dispersing the intermediate in an organic solvent, slowly dripping a mixed solution of dimethyl phosphite and carbon tetrachloride at 0-30 ℃, then dripping an acid-binding agent, continuously reacting for 12-18 h at 0-50 ℃, obtaining a halamine antibacterial flame retardant precursor after the reaction is finished, finally dissolving the halamine antibacterial flame retardant precursor in hypochlorite/trichloroisocyanurate with the mass percentage concentration of 0.1-10% for a period of time, filtering and drying to obtain the halamine antibacterial flame retardant, wherein the derivative of the cyanuric chloride or the cyanuric fluoride is a derivative of which one chlorine/fluorine atom is covered by C₁-C₈Alkyl, cycloalkyl, methoxy, fluoro/chloro, bromo, hydroxy or phosphate substitution.

The structural formula of the compound of the halamine antibacterial flame retardant obtained by the reaction is shown as the formula (I):

wherein R represents chlorine or bromine;

R₁represents C₁～C₈Alkyl, cycloalkyl, fluoro, chloro, bromo, hydroxy or phosphate;

R₂represents fluorine or chlorine.

The structural formula of the compound of the halamine antibacterial flame retardant precursor obtained by the reaction is shown as the formula (II):

R₁represents C₁～C₈Alkyl, cycloalkyl, fluoro, chloro, bromo, hydroxy or phosphate;

R₂represents fluorine or chlorine.

Further, the organic solvent for dissolving the cyanuric chloride or the cyanuric fluoride or the derivative of both and the dispersion intermediate is selected from tetrahydrofuran, chloroform, carbon tetrachloride, ethanol, diethyl ether, acetone and dioxane.

Further, the acid binding agent is selected from one or a mixture of more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine, sodium methoxide and potassium ethoxide.

Further, the hypochlorite/trichloroisocyanurates are selected from one or more of sodium hypochlorite, potassium hypochlorite, calcium hypochlorite and sodium trichloroisocyanurates; the pH value of the hypochlorite/trichloroisocyanuric acid salt solution is 7-12, and the effective chlorine content is 0.1-5%.

The application of the halamine antibacterial flame retardant in the antibacterial flame-retardant finishing of the textile comprises the following processes:

dissolving a halamine antibacterial flame retardant in an organic solvent to prepare a finishing liquid with the mass fraction of 10-50%, adding an alkaline agent, then soaking the textile in the finishing liquid for 15-60 min, finishing the textile by adopting the traditional two-dipping and two-rolling, pre-drying at 80-110 ℃ for 1-10 min, baking at 120-160 ℃ for 2-8 min, and drying after water washing to prepare the antibacterial flame-retardant textile.

Or dissolving the halamine antibacterial flame retardant precursor and an alkaline agent in an organic solvent to prepare a finishing liquid with the mass fraction of 25-50%, then finishing, pre-drying, baking, washing and drying the textile by adopting the traditional two-dipping and two-rolling method to prepare the flame-retardant textile, finally soaking the dried textile in hypochlorite/trichloroisocyanuric acid with the mass percentage concentration of 1-10%, taking out the cotton fabric after waiting for a period of time, and drying to prepare the halamine antibacterial flame-retardant textile.

Further, the organic solvent is one or more mixed solutions of absolute ethyl alcohol, isopropanol, DMF, DMSO, chloroform and carbon tetrachloride.

Furthermore, the molar ratio of the addition amount of the alkali agent to the haloamine antibacterial flame retardant is 2: 1-1: 2.

Further, the alkaline agent is selected from one or a mixture of more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine, sodium methoxide and potassium ethoxide.

Further, the hypochlorite/trichloroisocyanurates are selected from one or more of sodium hypochlorite, potassium hypochlorite, calcium hypochlorite and sodium trichloroisocyanurates; compared with the prior art, the pH value of the hypochlorite solution is 7-12, and the effective chlorine content is 0.1-5%, the invention has the following beneficial effects:

1. according to the preparation method of the halamine antibacterial flame retardant, the amino compound and the phosphorus-containing group are organically combined by utilizing the specific reaction activity of cyanuric chloride to prepare the flame retardant (multifunctional finishing agent) with high-efficiency sterilization and phosphorus/nitrogen synergistic effect, the finishing agent has three functions of high reaction activity, antibacterial property and flame retardant property, and the problem of unsatisfactory antibacterial and flame retardant effects caused by competitive reaction in the combined use of the conventional antibacterial agent and the flame retardant is solved.

2. According to the application of the halamine antibacterial flame retardant in the antibacterial flame-retardant finishing of the textile, the prepared halamine antibacterial flame retardant can be covalently bonded with fibers at a lower temperature, so that the problems of poor durability, serious strength damage and the like are avoided.

3. The application of the halamine antibacterial flame retardant in the antibacterial flame-retardant finishing of the textile can kill 10 percent of the prepared antibacterial flame-retardant textile within 1min⁶～10⁸The CFU has staphylococcus aureus and escherichia coli, has excellent flame retardant property and can pass a vertical combustion test.

4. The preparation method and the application of the halamine antibacterial flame retardant are simple and convenient to operate and meet the processing requirements of ecological textiles.

Drawings

FIG. 1 is a synthesis route diagram of a precursor of the halamine-based antibacterial flame retardant and the halamine-based antibacterial flame retardant in example 1 of the present invention;

FIG. 2 is a schematic view of the antibacterial performance and the regeneration performance of the halogen amine type antibacterial flame retardant in application example 1 of the present invention;

fig. 3 is a schematic view of a vertical burning test of the halamine-based antibacterial flame-retardant textile according to application example 1 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

Preparation examples of Haloamine antibacterial flame retardant

The first embodiment is as follows:

the preparation of the halamine antibacterial flame retardant (2, 4-dichloro-6- (chloridized dimethoxyphosphamidoamine) -1,3, 5-triazine) is shown in the synthesis scheme of figure 1.

Weighing 0.05mol of cyanuric chloride, dispersing the cyanuric chloride in 100mL of water, weighing 0.15mol of 25 wt% ammonia water, mixing the cyanuric chloride and the ammonia water in a 500mL round-bottom flask, placing the flask in an ice bath, fully and uniformly stirring, reacting at 0 ℃ for 2h, filtering according to a conventional operation method after the reaction is finished, washing with distilled water, drying, dispersing the obtained solid in tetrahydrofuran, weighing 0.05mol of dimethyl phosphite, carbon tetrachloride and triethylamine, and dripping in the ice-water bath condition. After the solution is completely dripped, the solution is transferred to room temperature to react for 12h, after the reaction is finished, the solution is filtered, rotary evaporated and dried according to a conventional method, the obtained solid is dried for 12h in a vacuum drying oven to obtain a halamine antibacterial flame-retardant precursor (2, 4-dichloro-6- (iminodimethoxyphosphoryl) -1,3, 5-triazine), finally the precursor is dissolved in a sodium hypochlorite solution with the mass percentage concentration of 10% and the pH value of 7, the solution is kept stand at the room temperature to react for 1h, after the reaction is finished, the solution is filtered and dried according to a conventional operation method (the same as above) to obtain a finished product of the halamine antibacterial flame retardant (2, 4-dichloro-6- (chloridized dimethoxyphosphoramide) -1,3, 5-triazine).

Example two:

preparation of halogen amine antibacterial flame retardant (2, 4-difluoro-6- (chloridized dimethoxy phosphamide amine) -1,3, 5-triazine).

Weighing 0.05mol of cyanuric fluoride, dispersing the cyanuric fluoride in 100mL of water, weighing 0.15mol of 25 wt% ammonia water, mixing the two in a 500mL round-bottom flask, placing the flask in an ice bath, fully and uniformly stirring, reacting at 5 ℃ for 4h, filtering according to a conventional operation method after the reaction is finished, washing with distilled water, drying, dispersing the obtained solid in tetrahydrofuran, weighing 0.05mol of dimethyl phosphite, carbon tetrachloride and triethylamine, and dripping at room temperature. Transferring to room temperature for reacting for 18h after dripping, filtering, rotary steaming and drying according to a conventional method after the reaction is finished, drying the obtained solid in a vacuum drying oven for 12h to obtain a halamine antibacterial flame-retardant precursor (2, 4-difluoro-6- (iminodimethoxyphosphoryl) -1,3, 5-triazine), finally dissolving the precursor in a trichloroisocyanuric acid solution with the mass percentage concentration of 1% and the pH value of 10, standing at room temperature for reacting for 1h, filtering and drying (the same as above) according to a conventional operation method after the reaction is finished, and obtaining a finished product of the halamine antibacterial flame retardant (2, 4-difluoro-6- (chloridized dimethoxyphosphoramide) -1,3, 5-triazine).

Example three:

preparation of halogen amine antibacterial flame retardant (2-chloro-4-methoxy-6- (chloridized dimethoxyphosphamide amine) -1,3, 5-triazine).

Weighing 0.05mol of cyanuric chloride derivative 2, 4-dichloro-6-methoxy-1, 3, 5-triazine, dissolving the cyanuric chloride derivative in 100mL of tetrahydrofuran, weighing 0.15mol of 25 wt% ammonia water, mixing the cyanuric chloride derivative and the ammonia water in a 500mL round-bottom flask, placing the flask in an ice bath, fully stirring the mixture uniformly, reacting at 5 ℃ for 6 hours, filtering the mixture according to a conventional operation method after the reaction is finished, washing the mixture with distilled water, drying the washed mixture, dispersing the obtained solid in the tetrahydrofuran, weighing 0.05mol of dimethyl phosphite, carbon tetrachloride and triethylamine, and dripping the mixture at 30 ℃. After the solution is completely dripped, the solution is transferred to 50 ℃ for reaction for 16h, after the reaction is finished, the solution is filtered, rotary evaporated and dried according to a conventional method, the obtained solid is dried in a vacuum drying oven for 12h to obtain a halamine antibacterial flame-retardant precursor (2-chloro-4-methoxy-6- (iminodimethoxyphosphoryl) -1,3, 5-triazine), finally the precursor is dissolved in a sodium hypochlorite solution with the mass percentage concentration of 5% and the pH value of 12, the solution is kept stand at room temperature for reaction for 1h, after the reaction is finished, the solution is filtered and dried according to a conventional operation method (the same as above) to obtain a finished product of the halamine antibacterial flame retardant (2-chloro-4-methoxy-6- (chlorinated dimethoxyphosphoramide) -1,3, 5-triazine).

Specific examples of the application of the two-halogen amine antibacterial flame retardant

The first application embodiment:

according to the molar ratio of a haloamine antibacterial flame retardant precursor (2, 4-dichloro-6- (imino dimethoxy phosphoryl) -1,3, 5-triazine) to an alkaline agent (triethylamine) of 1: 0.5 preparing finishing liquid with the mass fraction of 30%. Then, finishing the cotton fabric by adopting a traditional two-dipping two-rolling process, pre-drying (100 ℃, 5min), baking (150 ℃, 5min), washing with water, drying (45 ℃, 1h), finally soaking the dried cotton fabric in a sodium hypochlorite solution with the mass percentage concentration of 0.1%, taking out the cotton fabric after 1h, and drying in a dryer at 45 ℃ for 2h to obtain the haloamine antibacterial flame-retardant cotton fabric.

The content of active chlorine of the halamine antibacterial flame-retardant cotton fabric is determined by an iodometry, the chlorine content is 0.58%, and the halamine antibacterial flame-retardant cotton fabric is sterilized by using the active chlorine.

As shown in fig. 2, the halamine antibacterial flame-retardant cotton fabric loses active chlorine after being sterilized, and can be immersed in hypochlorite/trichloroisocyanuric acid salt with the mass percentage concentration of 1-10% to perform halogenation reaction to obtain active chlorine again, namely, the sterilization effect is obtained again, namely, the halamine antibacterial flame retardant loses active halogen during the sterilization process and becomes a halamine antibacterial flame retardant precursor, and the halamine antibacterial flame retardant precursor becomes a halamine antibacterial flame retardant from newly obtained halogen through halogenation reaction.

Testing the antibacterial performance of the textile: the test was performed according to the method described in the modified AATCC100-2012 antibacterial performance test standard.

The antimicrobial finish was applied as described in the application examples, but not as a blank sample by halogenation. The cotton fabric obtained from the above-mentioned example (blank) and the cotton fabric obtained from the specific examples of application, which had not been halogenated, were tested for their antibacterial properties, the inoculated bacteria were Staphylococcus aureus and Escherichia coli 0157: H7, the test results are shown in tables 1 and 2, respectively.

TABLE 1 antibacterial Properties of Halamine antibacterial flame retardant textiles against Staphylococcus aureus

Note: inoculation concentration of staphylococcus aureus: 1X 10⁷CFU

Table 2 haloamine antimicrobial flame retardant textile versus escherichia coli O157: antibacterial property of H7

Note: escherichia coli O157: inoculation concentration of H7: 1X 10⁷CFU

The test data in tables 1 and 2 show that when the halamine antibacterial flame retardant is applied to antibacterial finishing of textiles, the prepared halamine antibacterial flame-retardant cotton fabric has high-efficiency and rapid antibacterial performance; after contact with the inoculated bacteria, the cotton fabric was resistant to staphylococcus aureus and escherichia coli 0157: the antibacterial rate of H7 reaches 99.99%.

Flame retardant performance test of textiles the flame retardant performance of the textiles was tested by the vertical burn test.

The antimicrobial finishing was carried out according to the method described in the specific examples of application, with untreated cotton samples as blank samples. Vertical burning tests were carried out on an air-white sample, the above cotton fabric which had not been subjected to halogenation reaction, and the antibacterial flame-retardant cotton fabric manufactured in application example 3.

As shown in FIG. 3, test data show that when the halamine antibacterial flame retardant is applied to flame retardant finishing of textiles, the prepared halamine antibacterial flame retardant cotton fabric has good flame retardant property; according to the definition of the flame retardant property of the textile in the national standard GB/T5454-. The antibacterial flame-retardant cotton fabric prepared by the invention has a phosphorus-nitrogen synergistic flame-retardant action mechanism, can form a stable carbon layer on the surface of a fiber in the combustion process, isolate the transfer of oxygen and heat, prevent the textile from further combustion, has the damaged carbon length less than 14cm in a vertical combustion test, can successfully pass the test standard, and has better flame-retardant performance.

Application example two:

according to the proportion of 1: 1 preparing finishing liquid with the mass fraction of 50%. Then, finishing the cotton fabric by adopting a traditional two-dipping two-rolling process, pre-drying (100 ℃, 10min), baking (120 ℃, 5min), washing with water, drying (45 ℃, 1h), finally soaking the dried cotton fabric in a sodium hypochlorite solution with the mass percentage concentration of 5%, taking out the cotton fabric after 1h, and drying in a dryer at 45 ℃ for 2h to obtain the halamine antibacterial/flame-retardant cotton fabric.

The active chlorine content of the halamine antibacterial flame-retardant cotton fabric is measured by an iodometry method, and the chlorine content is 0.43 percent; the fabric successfully passed the vertical burn test.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.