Method for measuring content of trace water in polyvinyl butyral film

Abstract

The invention discloses a method for measuring the content of trace water in a polyvinyl butyral film, and belongs to the technical field of trace water detection.The measuring method comprises the steps that the polyvinyl butyral film is added into an alcohol solvent and then sealed and heated, and a sample solution is obtained after the polyvinyl butyral film is completely dissolved; measuring the water content of the alcohol solvent and the water content of the sample solution by adopting a Karl Fischer moisture meter, subtracting the moisture in the alcohol solvent used for preparing the sample solution from the total moisture of the sample solution to obtain the moisture in the film, and calculating the ratio of the moisture in the film to the mass of the film to obtain the trace water content in the polyvinyl butyral film. According to the invention, the polyvinyl butyral film is completely dissolved, so that water in the polyvinyl butyral film is fully released into the solvent, and the test result is more accurate; the Karl Fischer moisture meter is adopted to measure the water content, so that the specificity is very high, the influence of other components on a test result is reduced, the measurement accuracy is high, the repeatability is good, the method is simple, the analysis time is short, and the analysis efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of trace moisture detection, and in particular relates to a method for determining the trace water content in a polyvinyl butyral film. Background Art

[0002] Polyvinyl butyral (PVB) film is a translucent film formed by extruding polyvinyl butyral resin with plasticizer. It has good adhesion to quartz glass, high transparency, heat resistance, cold resistance and high mechanical strength. It is an excellent bonding polymer material for making laminated glass. There will be a certain amount of water remaining in the finished PVB film, which is generally required to be within 1%. If the water content is too low, the adhesion between the contact surface and the glass will be weakened. If the water content is too high, bubbles will exist in the film. Therefore, controlling the water content plays an important role in process regulation. The industry mainly uses the drying loss method for determination, and the reference standard is mainly JC / T2166-2013 "Polyvinyl butyral (PVB) film for laminated glass". By placing 3 pieces of 50mm×50mm film in a 40℃ vacuum drying oven for 3 hours, the weight loss of the sample before and after drying is weighed and used as the moisture content value. However, for sheet samples, the moisture inside the film may not be able to evaporate completely, and the evaporated components may also contain other low-boiling point components, resulting in large errors in the measurement results.

[0003] Therefore, when determining trace moisture in chemical products, the industry generally tends to choose the Karl Fischer method with higher specificity, referring to the standard GB / T6283-2008 "Determination of Water Content in Chemical Products - Karl Fischer Method (General Method)". However, the premise of adopting this method standard is that the sample is easily soluble in the reagents (methanol, chloroform, etc.) in the Karl Fischer method and does not react with the reagents, so that the water in the sample is completely released into the reagents. However, PVB film cannot be directly and completely dissolved in the reagents in the Karl Fischer method under electromagnetic stirring conditions, resulting in errors in the determination. It is necessary to design a Karl Fischer determination method for trace moisture specifically for PVB film.

[0004] Therefore, it is of great significance to explore methods that can accurately detect the water content in PVB film. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining the trace water content in a polyvinyl butyral film, so as to achieve accurate detection of the trace water content in the polyvinyl butyral film.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The present invention provides a method for determining the trace water content in a polyvinyl butyral film, and the specific steps of the determination method are as follows:

[0008] Step 1, preparing a sample solution: adding an alcohol solvent to a polyvinyl butyral film, sealing and heating the film, and completely dissolving the film to obtain a sample solution;

[0009] Step 2: Determine the water content in the solvent and the sample solution: Use a Karl Fischer moisture analyzer to determine the water content of the alcohol solvent used in step 1 and the water content of the sample solution;

[0010] Step 3. Calculate the trace water content in the film: subtract the water content in the alcohol solvent used to prepare the sample solution from the total water content of the sample solution to obtain the water content in the film. Calculate the ratio of the water content in the film to the mass of the film to obtain the trace water content in the polyvinyl butyral film.

[0011] According to GB / T6283-2008 "Determination of Water Content in Chemical Products - Karl Fischer Method (General Method)", when using a Karl Fischer moisture meter to detect the water content of PVB film, the determination steps are: first add methanol or other sample solvents (methanol and pyridine mixture, ethylene glycol methyl ether and pyridine mixture, glacial acetic acid, pyridine, methanol and chloroform mixture), turn on the electromagnetic stirrer, drip Karl Fischer reagent until the color is brown, eliminate the water in methanol, then add the sample, drip Karl Fischer reagent until the color is brown, and the Karl Fischer reagent at this time reacts with the water in the sample. According to the above steps, it can be seen that there are only electromagnetic stirring conditions in the entire test process, and the process of dripping Karl Fischer reagent for titration to determine the end point takes a short time. If the sample cannot be completely dissolved in a short time, the internal water cannot be completely released, and the determination of the end point is inaccurate, and the detection result has deviations. The detection method provided by the present invention can achieve complete dissolution of polyvinyl butyral film and accurately determine the water content in the film.

[0012] Furthermore, in step 1, the mass of the polyvinyl butyral film is 1.5-2.0 g. When the water content is detected by a Karl Fischer titrator, the sample mass must meet the detection requirements. When the water content of the sample is 1000 ppm, the sample weight is recommended to be 1.0 g. Selecting the optimal injection volume can improve the accuracy of the detection.

[0013] Furthermore, in step 1, the mass of the alcohol solvent is 8-9 g. If the mass of the alcohol solvent is too high, the sample dilution will be too high, and the detection accuracy will decrease. If the mass of the alcohol solvent is too low, it will be difficult to completely dissolve the polyvinyl butyral film.

[0014] Furthermore, in step 1, the alcohol solvent is one of methanol, ethanol and n-butanol, the solubility of polyvinyl butyral film in alcohol solvents is relatively high, and the heating conditions can quickly and completely dissolve it.

[0015] Furthermore, the purity specification of the alcohol solvent is analytical grade.

[0016] Furthermore, in step 1, the sealing heating is performed by water bath heating, which can avoid the error in water content detection caused by water evaporation during the dissolution process.

[0017] Furthermore, in step one, the heating temperature of the sealing heating is 60-80°C.

[0018] Furthermore, in step 2, the sample solution is cooled to room temperature before the water content is measured.

[0019] Furthermore, in step 2, the specific steps of determining the water content in the solvent and the sample solution are as follows:

[0020] Use a Karl Fischer titrator to measure the water content of the alcohol solvent used in step one, repeat the measurement 3 times or more, and take the average value; measure the water content of the sample solution obtained in step one, repeat the measurement 3 times or more, and take the average value.

[0021] Furthermore, in step 2, 10 μL of ultrapure water was used as a standard sample to determine the titer of the Karl Fischer reagent, and the measurement was repeated 3 times to obtain an average value.

[0022] Furthermore, the Karl Fischer moisture analyzer is pre-titrated to balance until the current indicated by the ammeter is less than 20uA before starting to detect the sample.

[0023] Furthermore, in step 2, the water content is determined by using a Karl Fischer titrator for three repeated measurements.

[0024] Furthermore, the specific calculation formula for calculating the trace water content in the film in step 3 is as follows:

[0025]

[0026] Wherein: the units of X, X1 and X2 are %; X is the trace water content in the polyvinyl butyral film; X1 is the average water content of the alcohol solvent used in step one; X2 is the average water content of the sample solution; m is the mass of the polyvinyl butyral film in step one, in g; m1 is the mass of the alcohol solvent used in step one, in g.

[0027] Furthermore, the mass value in the formula is accurate to 0.0001 g.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention first completely dissolves the polyvinyl butyral film with an alcohol solvent under sealed heating conditions, so that the water in the polyvinyl butyral film is fully released into the solvent, and the test result is more accurate; the Karl Fischer titrator is used to measure the water content with high specificity, reducing the influence of other components on the test result, and the measurement accuracy is high and the repeatability is good. In addition, the method is simple, the analysis time is short, and the analysis efficiency is high.

[0030] (2) Polyvinyl butyral film is a polymer and is not easy to dissolve quickly in alcohol solvents. The water content in polyvinyl butyral film can be indirectly determined by measuring the water content of the solvent and the sample solution (polyvinyl butyral film dissolved in alcohol solvent), which broadens the application range of Karl Fischer moisture analyzer in polymers. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.9108g, add it to a methanol solvent with a mass of m1 = 8.6744g, seal it and heat it in a water bath at 65°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0034] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0035] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of methanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in methanol is recorded. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.148%. The water content of the sample solution obtained in step 1 is tested in the same way, and the measurement is repeated 3 times to take the average value, which is recorded as X2=0.197%. The specific data are shown in Table 1.

[0036] Table 1

[0037] Number of measurements Methanol water content (%) Water content of sample solution (%) 1 0.153 0.201 2 0.147 0.196 3 0.144 0.194 average value 0.148 0.197

[0038] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0039]

[0040] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the methanol solvent in step 1, in g.

[0041] Calculation results: Water content of polyvinyl butyral film X = 0.442%.

[0042] Example 2

[0043] The difference from Example 1 is that the film quality detection in step 1 is different. The specific detection steps are as follows:

[0044] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.6357g, add it to a methanol solvent with a mass of m1 = 8.2569g, seal it and heat it in a water bath at 65°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0045] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0046] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of methanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in methanol is recorded. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.147%; the water content of the sample solution obtained in step 1 is tested in the same way, and the measurement is repeated 3 times to take the average value, which is recorded as X2=0.196%. The specific data are shown in Table 2.

[0047] Table 2

[0048] Number of measurements Methanol water content (%) Water content of sample solution (%) 1 0.149 0.196 2 0.146 0.198 3 0.145 0.195 average value 0.147 0.196

[0049] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0050]

[0051] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the methanol solvent in step 1, in g.

[0052] Calculation results: Water content of polyvinyl butyral film X = 0.443%.

[0053] Example 3

[0054] The difference from Example 1 is that the film quality detection in step 1 is different. The specific detection steps are as follows:

[0055] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.7612g, add it to a methanol solvent with a mass of m1 = 8.4053g, seal it and heat it in a water bath at 65°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0056] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0057] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of methanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in methanol is recorded. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.148%. The water content of the sample solution obtained in step 1 is tested in the same way, and the measurement is repeated 3 times to take the average value, which is recorded as X2=0.199%. The specific data are shown in Table 3.

[0058] Table 3

[0059] Number of measurements Methanol water content (%) Water content of sample solution (%) 1 0.151 0.198 2 0.148 0.200 3 0.146 0.200 average value 0.148 0.199

[0060] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0061]

[0062] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the methanol solvent in step 1, in g.

[0063] Calculation results: Water content of polyvinyl butyral film X = 0.442%.

[0064] Example 4

[0065] The difference from Example 1 is that the methanol solvent in step 1 is replaced by ethanol solvent, and the specific detection steps are as follows:

[0066] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.6244g, add it to an ethanol solvent with a mass of m1 = 8.2463g, seal it and heat it in a water bath at 70°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0067] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0068] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of ethanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in ethanol is recorded. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.119%. The water content of the sample solution obtained in step 1 is tested in the same way, and the measurement is repeated 3 times to take the average value, which is recorded as X2=0.172%. The specific data are shown in Table 4.

[0069] Table 4

[0070]

[0071]

[0072] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0073]

[0074] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the ethanol solvent in step 1, in g.

[0075] Calculation results: Water content of polyvinyl butyral film X = 0.441%.

[0076] Example 5

[0077] The difference from Example 4 is that the film quality detection in step 1 is different. The specific detection steps are as follows:

[0078] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.5466g, add it to an ethanol solvent with a mass of m1 = 8.1053g, seal it and heat it in a water bath at 70°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0079] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0080] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of ethanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in ethanol is recorded. The result is repeated 3 times and the average value is recorded as X1=0.118%. The water content of the sample solution obtained in step 1 is tested in the same way, and the average value is repeated 3 times and recorded as X2=0.170%. The specific data are shown in Table 5.

[0081] Table 5

[0082] Number of measurements Ethanol water content (%) Water content of sample solution (%) 1 0.122 0.169 2 0.116 0.172 3 0.117 0.170 average value 0.118 0.170

[0083] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0084]

[0085] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the ethanol solvent in step 1, in g.

[0086] Calculation results: Water content of polyvinyl butyral film X = 0.443%.

[0087] Example 6

[0088] The difference from Example 4 is that the film quality detection in step 1 is different. The specific detection steps are as follows:

[0089] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.9689g, add it to an ethanol solvent with a mass of m1 = 8.8105g, seal it and heat it in a water bath at 70°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0090] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0091] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of ethanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in ethanol is recorded. The result is repeated 3 times and the average value is recorded as X1=0.119%. The water content of the sample solution obtained in step 1 is tested in the same way, and the average value is repeated 3 times and recorded as X2=0.179%. The specific data are shown in Table 6.

[0092] Table 6

[0093] Number of measurements Ethanol water content (%) Water content of sample solution (%) 1 0.118 0.178 2 0.121 0.180 3 0.117 0.179 average value 0.119 0.179

[0094] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0095]

[0096] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the ethanol solvent in step 1, in g.

[0097] Calculation results: Water content of polyvinyl butyral film X = 0.447%.

[0098] Example 7

[0099] The difference from Example 1 is that the methanol solvent in step 1 is replaced by n-butanol solvent, and the specific detection steps are as follows:

[0100] Step 1, prepare sample solution: weigh a polyvinyl butyral film with a mass of m = 1.7495g, add it to a n-butanol solvent with a mass of m1 = 8.3971g, seal it and heat it in a water bath at 80°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0101] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0102] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of n-butanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in n-butanol is recorded. The result is repeated 3 times to take the average value, which is recorded as X1=0.105%. The water content of the sample solution obtained in step 1 is tested in the same way, and the average value is repeated 3 times to take the average value, which is recorded as X2=0.163%. The specific data are shown in Table 7.

[0103] Table 7

[0104] Number of measurements Water content of n-butanol (%) Water content of sample solution (%) 1 0.105 0.162 2 0.108 0.162 3 0.103 0.164 average value 0.105 0.163

[0105] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0106]

[0107] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film; m is the mass of the polyvinyl butyral film in step 1, in g; m1 is the mass of the n-butanol solvent in step 1, in g.

[0108] Calculation results: Water content of polyvinyl butyral film X = 0.441%.

[0109] Comparative Example 1

[0110] Compared with Example 1, this comparative example adopts the traditional drying method to detect the moisture content of the film, and the specific detection steps are as follows:

[0111] S1. Take 3 pieces of polyvinyl butyral film with a size of 50mm×50mm, and use tweezers to put the polyvinyl butyral film into a dried constant-weight weighing bottle and weigh it (accurate to 0.0001g), and record the mass m0 as 9.0368g.

[0112] S2. Put the weighing bottle and the film into a 40℃ vacuum box at a negative pressure of 8.5×10 4 Keep it below Pa for 3h, then take out the weighing bottle and put it into the desiccator to cool naturally for 30min, take it out and weigh it, and record the mass m t It is 9.0013g.

[0113] S3. Calculate the water content of polyvinyl butyral film according to the formula, which is as follows:

[0114]

[0115] Where, W is the water content of polyvinyl butyral film, in %; m0 is the mass before drying, in g; m t It is the mass after drying, in g.

[0116] Calculation results: Water content of polyvinyl butyral film W = 0.393%

[0117] The film taken out after drying in S2 is tested according to the testing steps of Example 1, and the specific steps are as follows:

[0118] Step 1, preparing a sample solution: cut any piece of the polyvinyl butyral film taken out after drying in the above S2, with a mass m=1.8943g, add it to a methanol solvent with a mass m1=8.6615g, seal it and heat it in a water bath at 65°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0119] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0120] Step 3, determine the water content in the solvent and sample solution: the Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, 5mL of methanol solvent is drawn by a syringe, weighed and recorded, and quickly added to the titration cup. After the reaction is completed, the water content in methanol is recorded. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.148%. The water content of the sample solution obtained in step 1 is tested in the same way, and the measurement is repeated 3 times to take the average value, which is recorded as X2=0.131%. The specific data are shown in Table 8.

[0121] Table 8

[0122] Number of measurements Methanol water content (%) Water content of sample solution (%) 1 0.149 0.129 2 0.149 0.132 3 0.146 0.131 average value 0.148 0.131

[0123] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0124]

[0125] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film in step one; m is the mass of the polyvinyl butyral film in step one, in g; m1 is the mass of the methanol solvent in step one, in g.

[0126] Calculation results: The moisture content of the dried polyvinyl butyral film is X = 0.053%.

[0127] Comparative Example 2

[0128] Compared with Comparative Example 1, in Comparative Example S2, the negative pressure is 8.5×10 4 Pa below 3h is adjusted to 5h, and the specific detection steps are as follows:

[0129] Compared with Example 1, this comparative example adopts the traditional drying method to detect the moisture content of the film, and the specific detection steps are as follows:

[0130] S1. Take 3 pieces of polyvinyl butyral film with a size of 50mm×50mm, and use tweezers to put the polyvinyl butyral film into a dried constant-weight weighing bottle and weigh it (accurate to 0.0001g), and record the mass m0 as 9.1563g.

[0131] S2. Put the weighing bottle and the film into a 40℃ vacuum box at a negative pressure of 8.5×10 4 Keep it below Pa for 5 hours, then take out the weighing bottle and put it into the desiccator to cool naturally for 30 minutes, take it out and weigh it, and record the mass m t It is 9.1187g.

[0132] S3. Calculate the water content of polyvinyl butyral film according to the formula, which is as follows:

[0133]

[0134] Where, W is the water content of polyvinyl butyral film, in %; m0 is the mass before drying, in g; m t It is the mass after drying, in g.

[0135] Calculation results: Water content of polyvinyl butyral film W = 0.411%

[0136] The film taken out after drying in S2 is tested according to the testing steps of Example 1, and the specific steps are as follows:

[0137] Step 1, preparing a sample solution: cut any piece of the polyvinyl butyral film taken out after drying in the above S2, with a mass m=1.7659g, add it to a methanol solvent with a mass m1=8.4420g, seal it and heat it in a water bath at 65°C, cool it to room temperature after the polyvinyl butyral film is completely dissolved, and obtain a sample solution;

[0138] Step 2. Calibration of the titer of Karl Fischer reagent: After the Karl Fischer titrator is turned on and stabilized, select the titer mode, pre-titrate and balance until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a micro-syringe to draw 10μL of ultrapure water, weigh it, and quickly add it to the titration cup. After the reaction is completed, the instrument records the titer result, repeat the measurement three times to get the average value, and save the titer result.

[0139] Step 3. Determine the water content in the solvent and sample solution: The Karl Fischer moisture meter enters the measurement mode, pre-titrates and balances until the current indicated by the ammeter is less than 20uA. After keeping stable for 1 minute, use a syringe to draw 5mL of methanol solvent, weigh and record, and quickly add it to the titration cup. After the reaction is completed, record the water content in methanol. Repeat the measurement 3 times and take the average value, which is recorded as X1=0.148%; test the water content of the sample solution obtained in step 1 in the same way, repeat the measurement 3 times and take the average value, which is recorded as X2=0.129%. See Table 9 for specific data.

[0140] Table 9

[0141] Number of measurements Methanol water content (%) Water content of sample solution (%) 1 0.147 0.126 2 0.147 0.132 3 0.150 0.130 average value 0.148 0.129

[0142] Step 4: Calculate the trace water content in the film: Calculate the trace water content in the polyvinyl butyral film according to the formula, the formula is as follows:

[0143]

[0144] Wherein: the units of X, X1 and X2 are %; X is the water content of the polyvinyl butyral film in step one; m is the mass of the polyvinyl butyral film in step one, in g; m1 is the mass of the methanol solvent in step one, in g.

[0145] Calculation results: The moisture content of the dried polyvinyl butyral film is X = 0.038%.

[0146] From the moisture content results obtained by the above embodiments, it can be seen that in embodiments 1-3, the RSD value of the moisture content X of the polyvinyl butyral film is calculated to be 0.13%, the RSD value of the moisture content X of the polyvinyl butyral film detected in embodiments 4-6 is 0.69%, and the RSD value of the moisture content X of the polyvinyl butyral film detected in embodiments 1-7 is 0.47%. The detection method provided by the present invention is simple, has high accuracy, small error, and high analysis efficiency, and can realize the accurate detection of trace water content in polyvinyl butyral film. Comparative Example 1 is detected with reference to the standard JC / T2166-2013 "Polyvinyl butyral (PVB) film for laminated glass". Combining Comparative Example 1 and Embodiment 1, it can be seen that the film dried by the traditional drying method is further detected by the method of Embodiment 1 of the present invention, wherein the moisture content can reach 0.053%, which is reflected in the traditional method of determining moisture by weight loss during drying, and the film still contains a certain amount of moisture, and its moisture content detection accuracy is not as good as that of Embodiment 1. On the basis of comparative example 1, the comparative example extended the drying time to detect the moisture content, and further detected it using the detection method of the present invention, which showed that after the drying time was extended, some water was still contained in the film and did not volatilize, and the overall detection time was long, and the detection efficiency was low.

[0147] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0148] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for determining trace water content in polyvinyl butyral film, characterized in that: The specific steps of the assay method are as follows: Step 1, preparing a sample solution: adding an alcohol solvent to a polyvinyl butyral film, sealing and heating the film, and completely dissolving the film to obtain a sample solution; Step 2: Determine the water content in the solvent and the sample solution: Use a Karl Fischer moisture analyzer to determine the water content of the alcohol solvent used in step 1 and the water content of the sample solution; Step 3. Calculate the trace water content in the film: subtract the water content in the alcohol solvent used to prepare the sample solution from the total water content of the sample solution to obtain the water content in the film. Calculate the ratio of the water content in the film to the mass of the film to obtain the trace water content in the polyvinyl butyral film.

2. The method for determining the trace water content in a polyvinyl butyral film according to claim 1, characterized in that: In step 1, the mass of the polyvinyl butyral film is 1.5-2.0g.

3. The method for determining the trace water content in a polyvinyl butyral film according to claim 1, characterized in that: In step 1, the mass of the alcohol solvent is 8-9g.

4. The method for determining the trace water content in a polyvinyl butyral film according to claim 1, characterized in that: In step 1, the alcohol solvent is one of methanol, ethanol and n-butanol.

5. The method for determining the trace water content in a polyvinyl butyral film according to claim 1, characterized in that: The purity specification of the alcohol solvent is analytical grade.

6. The method for determining trace water content in polyvinyl butyral film according to claim 1, characterized in that: In step 1, the sealing heating is performed by water bath heating.

7. The method for determining trace water content in polyvinyl butyral film according to claim 1, characterized in that: In step 1, the heating temperature of the sealing heating is 60-80°C.

8. The method for determining trace water content in polyvinyl butyral film according to claim 1, characterized in that: In step 2, the sample solution is cooled to room temperature and then the water content is measured.

9. The method for determining trace water content in polyvinyl butyral film according to claim 1, characterized in that: In step 2, the specific steps of determining the water content in the solvent and the sample solution are as follows: Use a Karl Fischer titrator to measure the water content of the alcohol solvent used in step one, repeat the measurement 3 times or more, and take the average value; measure the water content of the sample solution obtained in step one, repeat the measurement 3 times or more, and take the average value.

10. The method for determining trace water content in polyvinyl butyral film according to claim 1, characterized in that: The specific calculation formula for calculating the trace water content in the film described in step 3 is as follows: Wherein: the units of X, X1 and X2 are %; X is the trace water content in the polyvinyl butyral film; X1 is the average water content of the alcohol solvent used in step one; X2 is the average water content of the sample solution; m is the mass of the polyvinyl butyral film in step one, in g; m1 is the mass of the alcohol solvent used in step one, in g.

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