Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a fluorine-containing phenyl aluminum phosphonate polymer and a preparation method thereof.
The invention provides a preparation method of a fluorine-containing phenyl aluminum phosphonate polymer, which comprises the following steps:
(1) Preparation of pentafluorophenyl phosphine dichloride: reacting bromopentafluorobenzene with magnesium powder in a solvent to obtain magnesium pentafluorophenyl bromide, and carrying out Grignard reaction on the magnesium pentafluorophenyl bromide and excessive phosphorus trichloride to obtain phosphorus pentafluorophenyl dichloride;
(2) Preparation of bis (pentafluorophenyl) phosphonium chloride and 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride): reacting 4,4 '-dibromo octafluorobiphenyl with magnesium powder in a solvent to prepare 4,4' -octafluorobiphenyl bis (magnesium bromide), and carrying out Grignard reaction on pentafluorophenyl magnesium bromide or the 4,4 '-octafluorobiphenyl bis (magnesium bromide) and excessive pentafluorophenyl phosphine dichloride to obtain bis (pentafluorophenyl) phosphine chloride or 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphine chloride);
(3) Preparation of bis (pentafluorophenyl) phosphonyl chloride and 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride): performing high-temperature oxidation on the bis (pentafluorophenyl) phosphonyl chloride or the 4,4 '-octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride) in phenylphosphonic acid to generate bis (pentafluorophenyl) phosphonyl chloride or 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride);
(4) Preparation of the fluorine-containing phenyl aluminum phosphonate polymer: reacting the bis (pentafluorophenyl) phosphonyl chloride, the 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) and aluminum hydroxide in toluene at the temperature of 0-20 ℃, filtering out aluminum trichloride, heating to 121-141 ℃ for dehydration reaction for 6-10 hours, and distilling out toluene to obtain the fluorine-containing phenyl aluminum phosphonate polymer.
Further, the solvent in the steps (1) and (2) is one or two of tetrahydrofuran or 2-methyltetrahydrofuran.
Further, in the step (1), the reaction temperature of the bromopentafluorobenzene and the magnesium powder is 50-65 ℃, the reaction time is 5-7 hours, the temperature of the Grignard reaction is 71-86 ℃, and the reaction time is 6-8 hours.
Further, in the step (1), the molar ratio of bromopentafluorobenzene to magnesium powder is 1.0-1.1, the mass ratio of the total mass of bromopentafluorobenzene and magnesium powder to the solvent is 350-500, and the molar ratio of magnesium pentafluorophenyl bromide to phosphorus trichloride is 1.
Further, in the step (2), the reaction temperature of the 4,4' -dibromo octafluorobiphenyl and the magnesium powder is 50-65 ℃, the reaction time is 5-7 hours, the temperature of the Grignard reaction is 71-86 ℃, and the reaction time is 6-8 hours.
Further, in the step (2), the molar ratio of the 4,4' -dibromo-octafluoro-biphenyl to the magnesium powder is 1.
Further, in the step (3), the mass ratio of the bis (pentafluorophenyl) phosphonyl chloride or the 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride) to the phenylphosphonic acid is 100-250.
Further, the temperature of the high-temperature oxidation in the step (3) is 240-260 ℃, and the oxidation time is 6-7 hours.
The phenylphosphonic acid in the invention plays a role as a solvent and a catalyst, and oxygen with the purity of 99.99 percent is introduced during high-temperature oxidation.
Further, in the step (4), the molar ratio of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) to bis (pentafluorophenyl) phosphonyl chloride is 1.
In the invention, bis (pentafluorophenyl) phosphonyl chloride, 4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) and part of aluminum hydroxide react to generate bis (pentafluorophenyl) phosphonic acid, 4' -octafluorobiphenyl bis (pentafluorophenyl phosphonic acid) and aluminum trichloride, the generated aluminum trichloride is firstly removed by filtration, and the bis (pentafluorophenyl) phosphonic acid, the 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonic acid) and the rest aluminum hydroxide undergo dehydration reaction (toluene carries water) at the temperature of 121-141 ℃ to prepare the fluorine-containing phenyl aluminum phosphonate polymer.
The invention also provides a fluorine-containing phenyl aluminum phosphonate polymer prepared by the method, wherein the weight average molecular weight of the fluorine-containing phenyl aluminum phosphonate polymer is not less than 5.58 multiplied by 10 6 。
The fluorine-containing phenyl aluminum phosphonate polymer prepared by the invention is off-white powder, and the specific chemical structural formula of the fluorine-containing phenyl aluminum phosphonate polymer is as follows:
wherein,
r is
R' is
Is a connecting key.
Compared with the prior art, the invention has the beneficial effects that:
the fluorine-containing phenyl aluminum phosphonate polymer has excellent flame retardant effect, excellent heat resistance, impact resistance, wear resistance, water repellency, fog resistance and other performances, and can be used for preparing high-temperature flame retardant instruments or appliances, high-precision instrument and meter waterproof and explosion-proof covers, airplane and automobile glass.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Example 1
The preparation method of the fluorine-containing phenyl aluminum phosphonate polymer comprises the following steps:
(1) Preparation of pentafluorophenyl phosphine dichloride:
adding 4.9g of magnesium powder and 250g of tetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 55 ℃, slowly dropwise adding 49.4g of bromopentafluorobenzene, reacting for 6.0 hours to generate magnesium pentafluorophenyl bromide, slowly dropwise adding a magnesium pentafluorophenyl bromide solution into 100g of phosphorus trichloride, gradually heating to 72 ℃, performing reflux reaction for 6 hours, performing suction filtration to remove salts, and distilling to remove tetrahydrofuran, redundant phosphorus trichloride and other impurities to obtain phosphorus pentafluorophenyl dichloride;
(2) Preparation of bis (pentafluorophenyl) phosphonium chloride:
preparing pentafluorophenyl magnesium bromide according to the method in the step (1), slowly dripping the prepared pentafluorophenyl magnesium bromide solution into 300g of pentafluorophenyl phosphine dichloride, then gradually heating to 74 ℃, carrying out reflux reaction for 5 hours, carrying out suction filtration to remove salt, and then distilling to remove tetrahydrofuran, redundant pentafluorophenyl phosphine dichloride and other impurities to obtain bis (pentafluorophenyl) phosphine chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride):
adding 4.9g of magnesium powder and 250g of tetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 60 ℃, slowly dropwise adding 45.6g of 4,4 '-dibromo octafluorobiphenyl for 5.0 hours to react to generate 4,4' -octafluorobiphenyl bis (magnesium bromide), then slowly dropwise adding a 4,4 '-octafluorobiphenyl bis (magnesium bromide) solution into 100g of pentafluorophenyl phosphine dichloride, gradually heating to 71 ℃, carrying out reflux reaction for 6 hours, carrying out suction filtration to remove salts, distilling to remove tetrahydrofuran, redundant pentafluorophenyl phosphine dichloride and other impurities to obtain 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphine chloride);
(3) Preparation of bis (pentafluorophenyl) phosphonyl chloride:
adding 51.2g of bis (pentafluorophenyl) phosphine chloride and 80g of anhydrous phenylphosphonic acid into a 500mL reactor, introducing nitrogen, stirring, heating to 240 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 7 hours, and then ending, evaporating the phenylphosphonic acid under reduced pressure to obtain bis (pentafluorophenyl) phosphonyl chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride):
adding 91.2g of 4,4 '-octafluorobiphenyl bi (pentafluorophenyl phosphonium chloride) and 140g of anhydrous phenylphosphonic acid into a 500mL reactor, introducing nitrogen, stirring, heating to 250 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 6 hours, and then distilling the phenylphosphonic acid under reduced pressure to obtain 4,4' -octafluorobiphenyl bi (pentafluorophenyl phosphonium chloride);
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 15 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 52.9g of bis (pentafluorophenyl) phosphonyl chloride and 103g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 121 ℃, performing dehydration reaction for 7 hours, evaporating the solvent toluene according to the fact that water distilled from a water separator meets the metering requirement, thus obtaining the off-white fluorine-containing phenyl aluminum phosphonate polymer with the weight-average molecular weight of 5.58 multiplied by 10 6 。
Example 2
The preparation method of the aluminum fluorophenylphosphonate-containing polymer of the embodiment comprises the following steps:
(1) Preparation of pentafluorophenyl phosphine dichloride:
adding 4.8g of magnesium powder and 190g of tetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 50 ℃, slowly and dropwise adding 49.4g of bromopentafluorobenzene, reacting for 7.0 hours to generate magnesium pentafluorophenyl bromide, slowly and dropwise adding a magnesium pentafluorophenyl bromide solution into 100g of phosphorus trichloride, gradually heating to 71 ℃, and carrying out reflux reaction for 8 hours. Filtering to remove salt, and distilling to remove tetrahydrofuran, redundant phosphorus trichloride and other impurities to obtain pentafluorophenyl phosphine dichloride;
(2) Preparation of bis (pentafluorophenyl) phosphonium chloride:
preparing pentafluorophenyl magnesium bromide according to the method in the step (1), slowly dripping the prepared pentafluorophenyl magnesium bromide solution into 150g of pentafluorophenyl phosphine dichloride, then gradually heating to 84 ℃, carrying out reflux reaction for 5 hours, carrying out suction filtration to remove salt, and then distilling to remove the solvent, redundant pentafluorophenyl phosphine dichloride and other impurities to obtain bis (pentafluorophenyl) phosphine chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride):
adding 4.8g of magnesium powder and 250g of tetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 65 ℃, slowly dropwise adding 45.6g of 4,4 '-dibromo octafluorobiphenyl for 5.0 hours to react to generate 4,4' -octafluorobiphenyl bis (magnesium bromide), then slowly dropwise adding the 4,4 '-octafluorobiphenyl bis (magnesium bromide) solution into 82g of pentafluorophenyl phosphine dichloride, gradually heating to 78 ℃, refluxing for 7 hours, performing suction filtration to remove salts, distilling to remove the solvent, redundant fluorophenyl phosphine dichloride and other impurities to obtain 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphine chloride);
(3) Preparation of bis (pentafluorophenyl) phosphonyl chloride:
adding 51.2g of bis (pentafluorophenyl) phosphine chloride and 100g of anhydrous phenylphosphonic acid into a 500mL reactor, introducing nitrogen, stirring, heating to 240 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 6.5 hours, and then ending, evaporating the phenylphosphonic acid under reduced pressure to obtain bis (pentafluorophenyl) phosphonyl chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride):
adding 91.2g of 4,4 '-octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride) and 180g of anhydrous phenylphosphonic acid into a 500mL reactor, stirring by introducing nitrogen, heating to 260 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 6.5 hours, and then ending, distilling out the phenylphosphonic acid under reduced pressure to obtain 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride);
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 0 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 52.9g of bis (pentafluorophenyl) phosphonyl chloride and 103g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 131 ℃, performing dehydration reaction for 6 hours, and distilling water out of a water separator according to the metering requirement. The solvent toluene was distilled off to obtain an off-white aluminum fluorophenylphosphonate polymer having a weight-average molecular weight of 6.42X 10 6 。
Example 3
The preparation method of the aluminum fluorophenylphosphonate-containing polymer of the embodiment comprises the following steps:
(1) Preparation of pentafluorophenyl phosphine dichloride:
adding 5.28g of magnesium powder and 270g of 2-methyltetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 65 ℃, slowly and dropwise adding 49.4g of bromopentafluorobenzene, reacting for 5.0 hours to generate magnesium pentafluorophenyl bromide, then slowly and dropwise adding a magnesium pentafluorophenyl bromide solution into 100g of phosphorus trichloride, gradually heating to 86 ℃, and carrying out reflux reaction for 6 hours. Filtering to remove salt, and distilling to remove 2-methyltetrahydrofuran, redundant phosphorus trichloride and other impurities to obtain pentafluorophenyl phosphine dichloride;
(2) Preparation of bis (pentafluorophenyl) phosphonium chloride:
preparing pentafluorophenyl magnesium bromide according to the method in the step (1), slowly dripping the prepared pentafluorophenyl magnesium bromide solution into 150g of pentafluorophenyl phosphine dichloride, then gradually heating to 74 ℃, carrying out reflux reaction for 5 hours, carrying out suction filtration to remove salt, and then distilling to remove the solvent, redundant pentafluorophenyl phosphine dichloride and other impurities to obtain bis (pentafluorophenyl) phosphine chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride):
adding 5.28g of magnesium powder and 210g of 2-methyltetrahydrofuran into a 500mL reactor, introducing nitrogen, starting stirring, heating to 65 ℃, slowly dropwise adding 45.6g of 4,4 '-dibromo octafluoro biphenyl for 5.0 hours to react to generate 4,4' -octafluoro biphenyl bis (magnesium bromide), then slowly dropwise adding the 4,4 '-octafluoro biphenyl bis (magnesium bromide) solution into 130g of pentafluorophenyl phosphine dichloride, gradually heating to 86 ℃, refluxing for 6 hours, filtering to remove salts, distilling to remove the solvent, redundant fluorophenyl phosphine dichloride and other impurities, and obtaining 4,4' -octafluoro biphenyl bis (pentafluorophenyl phosphine chloride);
(3) Preparation of bis (pentafluorophenyl) phosphonyl chloride:
adding 51.2g of bis (pentafluorophenyl) phosphine chloride and 130g of anhydrous phenylphosphonic acid into a 500mL reactor, introducing nitrogen, stirring, heating to 260 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 7 hours, and then ending, decompressing and distilling out the phenylphosphonic acid to obtain bis (pentafluorophenyl) phosphonyl chloride;
preparation of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride):
adding 91.2g of 4,4 '-octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride) and 228g of anhydrous phenylphosphonic acid into a 500mL reactor, stirring by introducing nitrogen, heating to 240 ℃, slowly introducing oxygen with the purity of 99.99%, observing the reflux condition, reacting for 7 hours, and then distilling out the phenylphosphonic acid under reduced pressure to obtain 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonium chloride);
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 25 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 52.9g of bis (pentafluorophenyl) phosphonyl chloride and 103g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 141 ℃, performing dehydration reaction for 10 hours, and distilling water out of a water separator according to the metering requirement. The solvent toluene was distilled off to obtain an off-white aluminum fluorophenylphosphonate polymer having a weight-average molecular weight of 6.62X 10 6 。
Example 4
The preparation method of the fluorine-containing phenyl aluminum phosphonate polymer comprises the following steps:
(1) - (3) Steps (1) to (3) in the same manner as in example 1;
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 15 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 52.9g of bis (pentafluorophenyl) phosphonyl chloride and 103.1g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 132 ℃, performing dehydration reaction for 6 hours, and distilling water from a water separator to meet the metering requirement. Steaming to remove the solvent ABenzene to give an off-white polymer of aluminum fluorophenylphosphonate having a weight average molecular weight of 6.76X 10 6 。
Example 5
The preparation method of the fluorine-containing phenyl aluminum phosphonate polymer comprises the following steps:
(1) - (3) Steps (1) to (3) in the same manner as in example 1;
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 15 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 39.6g of bis (pentafluorophenyl) phosphonyl chloride and 128.8g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 128 ℃, performing dehydration reaction for 8h, and according to the fact that water distilled out of a water separator meets the metering requirement. The solvent toluene was distilled off to obtain an off-white aluminum phenylphosphonate-containing polymer having a weight-average molecular weight of 7.87X 10 6 。
Example 6
The preparation method of the fluorine-containing phenyl aluminum phosphonate polymer comprises the following steps:
(1) - (3) Steps (1) to (3) of example 1;
(4) Preparation of fluorine-containing phenyl aluminum phosphonate polymer:
adding 250g of toluene into a 500mL reactor, adjusting the temperature to 15 ℃, adding 15.6g of aluminum hydroxide, introducing nitrogen, stirring, slowly adding 26.5g of bis (pentafluorophenyl) phosphonyl chloride and 154.5g of 4,4' -octafluorobiphenyl bis (pentafluorophenyl phosphonyl chloride) into the reactor, cooling and filtering to remove aluminum trichloride after the reaction is stable, slowly raising the temperature to 135 ℃, performing dehydration reaction for 7 hours, and distilling water from a water separator according to the metering requirement. The solvent toluene was distilled off to obtain an off-white fluorine-containing aluminum phenylphosphonate polymer having a weight-average molecular weight of 8.46X 10 6 。
Test example 1
(1) Flame retardancy test
The fluorine-containing phenyl aluminum phosphonate polymers prepared in examples 1 to 6 were sampled and designated as test samples 1 to 6.
The limit oxygen index of the sample is measured by referring to GB/T2406-2008 'test method for plastic combustion performance-oxygen index method', and the result is shown in Table 1.
TABLE 1
Sample (I)
|
Test sample 1
|
Test sample 2
|
Test sample No. 3
|
Test sample 4
|
Test sample No. 5
|
Test sample 6
|
LOI
|
35.3
|
36.5
|
37.5
|
35.6
|
36.9
|
37.8 |
LOI 28 is a flame-retardant limiting oxygen index, and the table 1 shows that the fluorine-containing phenyl aluminum phosphonate polymer prepared by the invention has excellent flame-retardant effect.
(2) Heat resistance test
The fluorine-containing phenyl aluminum phosphonate polymers prepared in examples 1 to 6 were sampled and designated as test samples 1 to 6.
The Vicat softening points of the test samples 1-6 were measured according to GB/T1633-2000 "determination of Vicat Softening Temperature (VST) of thermoplastics" and the results are shown in Table 2.
TABLE 2
It can be seen from Table 2 that the aluminum fluorophenylphosphonate containing polymer prepared by the invention has high temperature resistance.
(3) Light transmittance test
The fluorinated aluminum phenylphosphonate-containing polymers prepared in examples 1 to 6 were pressed at 335 to 350 ℃ to form glass slides having a thickness of 5mm, and the glass slides were recorded as test samples 1 to 6, and the light transmittance (%) was measured with reference to GB/T40415-2021 "method for measuring light transmittance of photovoltaic glass module for construction", and is shown in Table 3.
TABLE 3
Sample(s)
|
Test sample 1
|
Test sample 2
|
Test sample No. 3
|
Test sample 4
|
Test sample No. 5
|
Test sample No. 6
|
Light transmittance(%)
|
92.4
|
91.8
|
90.7
|
91.6
|
90.5
|
89.3 |
As can be seen from the data in Table 3, the fluorine-containing aluminum phenylphosphonate polymer prepared by the method of the present invention has good light transmittance.
(4) Impact resistance test
The fluorinated phenylphosphonic acid aluminum polymers prepared in examples 1 to 6 were prepared into dumbbell-shaped sample bars, which were recorded as test samples 1 to 6, and the impact strength (KJ/m) at the notch of the simple beam was measured with reference to GB/T1043-92 method for testing impact strength of simple beam for rigid plastics 2 ) The results are shown in Table 4.
TABLE 4
As can be seen from the data in Table 4, the fluorinated aluminum phenylphosphonate-containing polymer prepared by the method of the present invention has excellent impact strength.
(5) Water repellency test
The fluorinated aluminum phenylphosphonate polymers prepared in examples 1 to 6 were respectively formed into films and designated as test samples 1 to 6, and the contact angles of the samples were measured in accordance with GB/T30693 to 2014, which is a measurement of contact angles between plastic films and water, and the results are shown in Table 5.
TABLE 5
Sample (I)
|
Test sample 1
|
Test sample 2
|
Test sample 3
|
Test sample 4
|
Test sample No. 5
|
Test sample No. 6
|
Contact angle (degree)
|
131
|
138
|
145
|
133
|
142
|
147 |
As can be seen from the contact angles in Table 5, the fluorinated aluminum phenylphosphonate-containing polymer prepared by the present invention has excellent antifogging and water repellency.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.