Polyvinyl acetal film and preparation method thereof
By adding phosphite intermediates and amide antioxidants in the synthesis of polyvinyl acetal film, the problem of yellowing of the film is solved, the antioxidant resistance of yellowing is improved, and the transparency and adhesion properties are ensured. stability.
Patent Information
- Application Number
- CN202411447656.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2024-12-27
AI Technical Summary
During the application process, polyvinyl acetal film turns yellow due to hydroxyl oxidation, which affects transparency and weakens adhesion performance. The existing antioxidant methods have problems with hydrolysis, agglomeration and degradation, making it difficult to effectively improve yellowing resistance.
The preparation method of modified polyvinyl acetal film is adopted, by adding phosphite intermediates and amide antioxidants during the synthesis process, the amount is controlled to achieve the synergistic effect of antioxidant, and a stable alcohol or ether structure is formed. Terminate the oxidation chain reaction and improve the antioxidant and yellowing resistance of the film.
It significantly improves the antioxidant and yellowing resistance of polyvinyl acetal film, reduces aging and degradation phenomena, maintains transparency and adhesion properties, and extends the service life of the film.
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Figure CN119192760A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a polyvinyl acetal film and a preparation method thereof. Background Art
[0002] Polyvinyl butyral (PVB) resin is an important chemical product. Its molecular structure contains hydroxyl, acetal and acetyl groups. It has good optical and safety properties and is mainly used in safety glass interlayer materials. When PVB films are used in safety glass interlayers or packaging materials, the hydroxyl groups in the molecular chain are oxidized, causing the PVB film to turn yellow, which affects transparency and weakens the adhesion between the film and the glass.
[0003] In order to overcome this problem, a variety of preparation methods for improving the yellowing resistance of PVB film have been disclosed, and these methods are basically based on the addition of antioxidants. As an auxiliary antioxidant, phosphite antioxidants have a synergistic effect when used in combination with primary antioxidants such as hindered phenols. However, phosphite antioxidants contain unbonded electrons and exhibit strong nucleophilic ability, so they are easily hydrolyzed. Hydrolysis can cause problems such as product agglomeration, acidic product corrosion, small molecule product migration, and reaction with other additives. When the general method is used to prepare PVB film, the film sometimes still has problems of aging and degradation during use, causing the film to turn yellow. Therefore, it is of great significance to develop a simple and effective method to solve the above problems. Summary of the invention
[0004] The object of the present invention is to provide a polyvinyl acetal film and a preparation method thereof, which can improve the anti-oxidation and yellowing resistance of the polyvinyl acetal film.
[0005] The purpose of the present invention can be achieved through the following technical solutions:
[0006] The present invention provides a polyvinyl acetal film, and its raw materials include, by weight:
[0007] 100 parts of modified polyvinyl acetal, 20-50 parts of plasticizer, 0.04-0.6 parts of primary antioxidant, 0.1-1.2 parts of auxiliary antioxidant;
[0008] The structural formula of the modified polyvinyl acetal is as follows:
[0009]
[0010] Among them, the content of structural units with acetal structure is 67-73 mol%, the content of structural units with hydroxyl structure is 26-30 mol%, the content of structural units with vinyl acetate structure is 1-2 mol%, and the content of structural units with phosphite structure is 0-1 mol%.
[0011] Furthermore, the preparation steps of the modified polyvinyl acetal are as follows:
[0012] S1. Preparation of reaction solution: dissolve polyvinyl alcohol in pure water and stir at 95°C for 3 hours to fully dissolve it to obtain a polyvinyl alcohol stock solution with a solid content of 8.0 wt%. Mix butyraldehyde and a phosphite intermediate to obtain a butyraldehyde reaction solution, wherein the mass fraction of the phosphite intermediate relative to butyraldehyde is 0.01 wt% to 0.5 wt%.
[0013] S2, homogeneous reaction stage: cool the polyvinyl alcohol stock solution to 20°C, then uniformly add hydrochloric acid with a mass concentration of 36% to 38% within 30 minutes, stir for 30 minutes to 40 minutes, then uniformly add butyraldehyde reaction solution within 30 minutes, and continue stirring and reacting for 30 minutes.
[0014] S3, high temperature aging stage: after the reaction, the temperature was raised to 40°C at 9°C / h, and the reaction was stirred at the constant temperature for 2h.
[0015] S4, washing and drying stage: after the reaction in S3, 15 wt% sodium hydroxide solution is added, stirred for 30 min, the pH is adjusted to neutral, centrifuged, washed, filtered, placed in a blast drying oven, and dried at 40° C. for 4 h to obtain modified polyvinyl acetal;
[0016] The degree of polymerization of the polyvinyl alcohol is 300 to 3000;
[0017] The structural formula of the phosphite intermediate is as follows:
[0018]
[0019] Furthermore, the preparation steps of the phosphite intermediate are as follows:
[0020] (1) 2,4-dicumylphenol and toluene are mixed, and after the 2,4-dicumylphenol is completely dissolved, an acid-binding agent, triethylamine, is added and the mixture is thoroughly mixed. Toluene is used as the reaction solvent.
[0021] (2) After mixing, the temperature is raised to 40° C., and under constant temperature stirring, a mixed solution of phosphorus trichloride and toluene is added dropwise in a molar ratio of phosphorus trichloride to 2,4-dicumylphenol of 1:1. After the addition is completed, the temperature is kept at 40° C. for 1 hour, and then the temperature is slowly raised to 50-70° C. and kept at this temperature for 3 hours to react.
[0022] (3) After the reaction is completed, the mixture is cooled to room temperature, 1 mol / L NaOH solution is added to adjust the pH to neutral, the hydrochloride in the reaction system is removed, the solvent toluene is removed by vacuum distillation, and the mixture is dried in vacuo for 4 h. The phosphite intermediate is then obtained by washing, filtering and drying.
[0023] Furthermore, the ratio of the 2,4-dicumylphenol to toluene is (0.01 mol to 0.03 mol): 50 mL.
[0024] Furthermore, the molar ratio of the acid-binding agent triethylamine to 2,4-dicumylphenol is 1.1:1.
[0025] Furthermore, the ratio of phosphorus trichloride to toluene in the mixed solution of phosphorus trichloride and toluene is (0.01 mol to 0.05 mol): 5 mL.
[0026] Furthermore, the mass ratio of the polyvinyl alcohol stock solution to the hydrochloric acid in S2 is 25:0.8-1.
[0027] Furthermore, the mass ratio of the polyvinyl alcohol stock solution to the butyraldehyde reaction solution in S2 is 25:1.2-1.3.
[0028] Furthermore, the plasticizer is one of plasticizer 3G7 and plasticizer 3G8.
[0029] Plasticizer is a substance added to materials to improve their processability, plasticity, flexibility and stretchability. Adding plasticizer can reduce melt viscosity and elastic modulus of the product without changing the basic chemical properties of the plasticized material. The plasticized PVB resin film has good flexibility.
[0030] Furthermore, the main antioxidant is one of antioxidant 1098 and antioxidant 1024.
[0031] The addition of amide antioxidants can capture free radicals produced under the influence of thermal oxygen, thereby preventing the next free radical chain reaction, cutting off the growth of the free radical chain, and achieving an antioxidant effect.
[0032] Furthermore, the auxiliary antioxidant is one of antioxidant 168, antioxidant 626, antioxidant PEP~36, antioxidant 627 and antioxidant 618.
[0033] Furthermore, the auxiliary antioxidant is one of antioxidant PEP-36 and antioxidant 626.
[0034] The addition of auxiliary antioxidant phosphites can remove the source of free radicals, reduce the generation of free radicals, and thus improve the thermal stability of the polymer.
[0035] The present invention also provides a method for preparing a polyvinyl acetal film, comprising the following steps:
[0036] The components in the raw materials are weighed according to the ratio, the main antioxidant and the auxiliary antioxidant are first mixed evenly, and then dissolved in the plasticizer to obtain a mixed solution, the mixed solution is added to the modified polyvinyl acetal, and the polyvinyl acetal film is obtained after melt extrusion through an extruder.
[0037] Beneficial effects of the present invention:
[0038] (1) A phosphite intermediate is synthesized by reacting 2,4-dicumylphenol toluene solution with phosphorus trichloride toluene solution in the presence of an acid-binding agent, triethylamine, and adding the phosphite intermediate to the synthesis process of polyvinyl acetal. The generated intermediate reacts with a few hydroxyl groups in the linear chain of polyvinyl alcohol (PVA) to form a phosphite structure, and finally a modified PVB is formed. Since the amount of the intermediate added in the synthesis process is very small, it will not affect other properties of PVB. The added phosphite structure will form a stable alcohol or ether structure with the peroxide generated during the aging process of the polyvinyl acetal film, terminate the chain reaction in the oxidation, and improve the antioxidant and yellowing resistance of the polyvinyl acetal film.
[0039] (2) Phosphite intermediates are added during the synthesis stage of polyvinyl acetal, and amide hindered phenol antioxidants and phosphite antioxidants are added during the processing stage. By controlling the dosage, the antioxidant effects of the three are combined to further optimize the antioxidant and yellowing resistance of the polyvinyl acetal film. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The present invention will be further described below in conjunction with the accompanying drawings.
[0041] Figure 1 It is a schematic diagram of the reaction process of preparing modified polyvinyl acetal according to the present invention.
[0042] Figure 2 It is a schematic diagram of the reaction process of preparing phosphite intermediates in the present invention. DETAILED DESCRIPTION
[0043] 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.
[0044] Example 1
[0045] Preparation of phosphite intermediates:
[0046] (1) 0.02 mol of 2,4-dicumylphenol was placed in a three-necked flask, and 50 mL of toluene was added to dissolve the 2,4-dicumylphenol. After the dissolution was completed, 0.022 mol of triethylamine, an acid-binding agent, was added to the three-necked flask and mixed thoroughly. Toluene was used as the reaction solvent.
[0047] (2) Add 0.02 mol of phosphorus trichloride to a 60 mL constant pressure dropping funnel, then add 5 mL of toluene to dilute, then connect the constant pressure dropping funnel, reflux condenser and thermometer to a three-necked flask, add a stirrer to the three-necked flask to form a reaction device. Place the reaction device in a 40°C constant temperature water bath, and when the reaction system stabilizes at 40°C, add the phosphorus trichloride and toluene mixed solution in the constant pressure dropping funnel under continuous stirring, and control the system temperature to fluctuate by no more than 2°C during the dropping process. After the addition is completed, keep the temperature at 40°C for 1 hour, slowly raise the temperature to 55°C, and keep the temperature for 3 hours to react.
[0048] (3) After the reaction is completed, the mixture is cooled to room temperature, 1 mol / L NaOH solution is added to adjust the pH to neutral, the hydrochloride in the reaction system is removed, the solvent toluene is removed by vacuum distillation, and the mixture is dried in vacuo for 4 h. The phosphite intermediate is then obtained by washing, filtering and drying.
[0049] Example 2
[0050] Preparation of modified polyvinyl acetal:
[0051] S1. Preparation of reaction solution: dissolve 100 g of polyvinyl alcohol (average degree of polymerization 450, degree of alcoholysis 99.05 wt%) in 1150 g of pure water, and stir at 95 ° C for 3 h to fully dissolve it to obtain a polyvinyl alcohol stock solution with a solid content of 8.0 wt%. Mix butyraldehyde and the phosphite intermediate prepared in Example 1 to obtain a butyraldehyde reaction solution, and the mass fraction of the phosphite intermediate relative to butyraldehyde is 0.01 wt%.
[0052] S2, homogeneous reaction stage: cool the polyvinyl alcohol stock solution to 20°C, then uniformly add 47.17g of hydrochloric acid with a mass concentration of 36% to 38% within 30min, stir for 30min to 40min, then uniformly add 60.05g of butyraldehyde reaction solution within 30min, and continue stirring and reacting for 30min.
[0053] S3, high temperature aging stage: after the reaction, the temperature was raised to 40°C at 9°C / h, and the reaction was stirred at the constant temperature for 2h.
[0054] S4, water washing and drying stage: after the reaction in S3, add 80 mL of 15 wt% sodium hydroxide solution, stir for 30 min, adjust the pH to neutral, dehydrate by centrifugation, repeat water washing and filtration at 40°C for 5 times, filter out the product, place it in a forced air drying oven, and dry it at 40°C for 4 h to obtain modified polyvinyl acetal.
[0055] Example 3
[0056] The difference between this embodiment and embodiment 2 is that the mass fraction of the phosphite intermediate added to the butyraldehyde reaction solution relative to butyraldehyde is adjusted to 0.05wt%. The other steps and conditions are the same as those in embodiment 2.
[0057] Example 4
[0058] The difference between this embodiment and embodiment 2 is that the mass fraction of the phosphite intermediate added to the butyraldehyde reaction solution relative to butyraldehyde is adjusted to 0.1wt%. The other steps and conditions are the same as those in embodiment 2.
[0059] Example 5
[0060] The difference between this embodiment and embodiment 2 is that the mass fraction of the phosphite intermediate added to the butyraldehyde reaction solution relative to butyraldehyde is adjusted to 0.5wt%. The other steps and conditions are the same as those in embodiment 2.
[0061] Example 6
[0062] Preparation of polyvinyl acetal film:
[0063] 100 parts of the modified polyvinyl acetal prepared in Example 2, 30 parts of plasticizer, 0.3 parts of antioxidant 1024 and 0.6 parts of antioxidant 626 were weighed according to their mass proportions. Antioxidant 1024 and antioxidant 626 were mixed and dissolved in plasticizer 3G8 at 60°C to obtain a mixed solution. The mixed solution was added to the modified polyvinyl acetal and melt-extruded through an extruder to obtain a polyvinyl acetal film.
[0064] Example 7
[0065] The only difference between this embodiment and embodiment 6 is that the modified polyvinyl acetal prepared in embodiment 3 is used to replace the modified polyvinyl acetal prepared in embodiment 2, and the other steps and conditions are the same as those in embodiment 6.
[0066] Example 8
[0067] The only difference between this embodiment and embodiment 6 is that the modified polyvinyl acetal prepared in embodiment 4 is used to replace the modified polyvinyl acetal prepared in embodiment 2, and the other steps and conditions are the same as those in embodiment 6.
[0068] Example 9
[0069] The only difference between this embodiment and embodiment 6 is that the modified polyvinyl acetal prepared in embodiment 5 is used to replace the modified polyvinyl acetal prepared in embodiment 2, and the other steps and conditions are the same as those in embodiment 6.
[0070] Example 10
[0071] The difference between this embodiment and embodiment 6 is that the antioxidant 626 is replaced by antioxidant PEP-36, and the other steps and conditions are the same as those in embodiment 6.
[0072] Embodiment 11
[0073] The difference between this embodiment and embodiment 6 is that the antioxidant 1024 is replaced by the antioxidant 1098, and the other steps and conditions are the same as those in embodiment 6.
[0074] Example 12
[0075] The difference between this embodiment and embodiment 6 is that the antioxidant 626 is replaced by the antioxidant PEP-36, and the antioxidant 1024 is replaced by the antioxidant 1098. The other steps and conditions are the same as those in embodiment 6.
[0076] Embodiment 13
[0077] The only difference between this embodiment and embodiment 6 is that the mass fraction of antioxidant 1024 is changed to 0.45 parts, the mass fraction of antioxidant 626 is changed to 0.45 parts, and the other steps and conditions are the same as those in embodiment 6.
[0078] Embodiment 14
[0079] The only difference between this embodiment and embodiment 6 is that the mass fraction of antioxidant 1024 is changed to 0.225 parts, the mass fraction of antioxidant 626 is changed to 0.675 parts, and the other steps and conditions are the same as those in embodiment 6.
[0080] Embodiment 15
[0081] The only difference between this embodiment and embodiment 6 is that the mass fraction of antioxidant 1024 is changed to 0.45 parts, the mass fraction of antioxidant 626 is changed to 0.9 parts, and the other steps and conditions are the same as those in embodiment 6.
[0082] Example 16
[0083] The only difference between this embodiment and embodiment 6 is that the mass fraction of antioxidant 1024 is changed to 0.6 parts, the mass fraction of antioxidant 626 is changed to 1.2 parts, and the other steps and conditions are the same as those in embodiment 6.
[0084] Comparative Example 1
[0085] The difference from Example 2 is that in this comparative example, no phosphite intermediate is added to the butyraldehyde reaction solution, and the other steps and conditions are the same as those in Example 2 to prepare polyvinyl acetal.
[0086] Comparative Example 2
[0087] The difference from Example 2 is that in this comparative example, the mass fraction of the phosphite intermediate added to the butyraldehyde reaction solution relative to butyraldehyde is adjusted to 0.009wt%, and the other steps and conditions are the same as Example 2 to prepare modified polyvinyl acetal.
[0088] Comparative Example 3
[0089] The difference from Example 2 is that in this comparative example, the mass fraction of the phosphite intermediate added to the butyraldehyde reaction solution relative to butyraldehyde is adjusted to 0.6wt%, and the other steps and conditions are the same as Example 2 to prepare modified polyvinyl acetal.
[0090] Comparative Example 4
[0091] The difference compared with Example 6 is that: this comparative example adopts the polyvinyl acetal prepared in Comparative Example 1 to replace the modified polyvinyl acetal prepared in Example 2, and the other steps and conditions are the same as Example 6 to prepare a polyvinyl acetal film.
[0092] Comparative Example 5
[0093] The difference compared with Example 6 is that: this comparative example uses the modified polyvinyl acetal prepared in Comparative Example 2 to replace the modified polyvinyl acetal prepared in Example 2, and the other steps and conditions are the same as Example 6 to prepare a polyvinyl acetal film.
[0094] Comparative Example 6
[0095] The difference compared with Example 6 is that: this comparative example adopts the polyvinyl acetal prepared in Comparative Example 3 to replace the modified polyvinyl acetal prepared in Example 2, and the other steps and conditions are the same as Example 6 to prepare a polyvinyl acetal film.
[0096] Comparative Example 7
[0097] The difference from Example 6 is that antioxidant 1024 and antioxidant 626 are not added to the raw materials of this comparative example, and the specific steps are as follows:
[0098] 100 parts of the modified polyvinyl acetal prepared in Example 2 and 30 parts of the plasticizer were weighed according to their mass fractions, the plasticizer 3G8 was added to the modified polyvinyl acetal, and the polyvinyl acetal film was obtained after melt extrusion through an extruder.
[0099] Comparative Example 8
[0100] The difference from Example 6 is that no antioxidant 626 is added to the raw materials of this comparative example, and the specific steps are as follows:
[0101] 100 parts of the modified polyvinyl acetal prepared in Example 2, 30 parts of the plasticizer and 0.3 parts of the antioxidant 1024 were weighed according to their mass proportions, the antioxidant 1024 was dissolved in the plasticizer 3G8 at 60°C to obtain a mixed solution, the mixed solution was added to the modified polyvinyl acetal, and the polyvinyl acetal film was obtained after melt-extrusion through an extruder.
[0102] Comparative Example 9
[0103] The difference from Example 6 is that the antioxidant 1024 is not added to the raw materials of this comparative example, and the specific steps are as follows:
[0104] 100 parts of the modified polyvinyl acetal prepared in Example 2, 30 parts of the plasticizer and 0.6 parts of the antioxidant 626 were weighed according to their mass proportions, the antioxidant 626 was dissolved in the plasticizer 3G8 at 60°C to obtain a mixed solution, the mixed solution was added to the modified polyvinyl acetal, and the polyvinyl acetal film was obtained after melt-extrusion through an extruder.
[0105] Comparative Example 10
[0106] The difference compared with Example 6 is that in this comparative example, antioxidant 246 replaces antioxidant 1024, and 0.225 parts of antioxidant 246 and 0.225 parts of antioxidant 626 are weighed. Other steps and conditions are the same as Example 6.
[0107] Comparative Example 11
[0108] The difference compared with Example 6 is that in this comparative example, antioxidant 168 replaces antioxidant 626, and other steps and conditions are the same as Example 6.
[0109] Comparative Example 12
[0110] The difference compared with Example 6 is that in this comparative example, the mass fraction of antioxidant 1024 is changed to 0.3 parts, the mass fraction of antioxidant 626 is changed to 0.09 parts, and the other steps and conditions are the same as Example 6.
[0111] Comparative Example 13
[0112] The difference compared with Example 6 is that in this comparative example, the mass fraction of antioxidant 1024 is changed to 0.03 parts, the mass fraction of antioxidant 626 is changed to 0.06 parts, and the other steps and conditions are the same as Example 6.
[0113] The films prepared in Examples 6 to 16 and Comparative Examples 4 to 13 were tested for color by baking the films in an electric constant temperature forced air drying oven at 260° C. for 20 minutes and observing the colors of the films. The results are shown in Table 1.
[0114] According to the raw material ratios for preparing polyvinyl acetal films in Examples 6 to 16 and Comparative Examples 4 to 13, the modified polyvinyl acetal or polyvinyl acetal is uniformly mixed with a plasticizer containing an antioxidant, poured between two pieces of glass, and pressed at 140 to 200° C. for 15 minutes using a flat vulcanizer to form a sandwich.
[0115] Method for measuring b value with spectrophotometer: Place the standard piece flat on the test white board, align the test window of the colorimeter with the standard piece, press the "measure" key, wait for the "standard color" calibration to be completed, press the key to switch to the "sample color" measurement mode, then align the instrument test window with the glass sample, press the "measure" key, and the screen will display the b value of the glass sample. The test results are shown in Table 1.
[0116] The b value range is between 0 and 1, which is white and transparent; the b value range is between 1 and 1.2, which is slightly yellow; the b value range is between 1.3 and 1.5, which is light yellow; the b value range is between 1.5 and 2.0, which is yellow; and the b value greater than 2.0 is dark yellow.
[0117] Table 1
[0118] project b-value color Example 6 0.89 White and transparent Example 7 0.70 White and transparent Example 8 0.66 White and transparent Example 9 0.6 White and transparent Example 10 0.76 White and transparent Embodiment 11 0.88 White and transparent Example 12 0.80 White and transparent Embodiment 13 1.35 Light yellow Embodiment 14 1.30 Light yellow Embodiment 15 1.16 Slightly yellow Example 16 1.33 Light yellow Comparative Example 4 2.22 Dark yellow Comparative Example 5 1.86 yellow Comparative Example 6 1.43 Slightly yellow Comparative Example 7 2.01 Dark yellow Comparative Example 8 1.78 yellow Comparative Example 9 1.98 yellow Comparative Example 10 1.33 Light yellow Comparative Example 11 1.03 Slightly yellow Comparative Example 12 1.05 Slightly yellow Comparative Example 13 1.06 Slightly yellow
[0119] As can be seen from Table 1, the films prepared in Examples 6 to 12 have significantly better yellowing resistance than the films prepared in the comparative examples. In Examples 6 to 9, as the amount of phosphite intermediates added during synthesis increases, the b value of the film detection gradually decreases, the yellowing resistance is improved, and the color change after oven baking is not obvious. In Examples 10 to 12, the types of antioxidants are adjusted, but the main antioxidant is still amide hindered phenols, and the auxiliary antioxidant is still phosphites. Compared with Example 6, it has less effect on the yellowing resistance of the film. In Examples 13 and 14, the ratio of the main antioxidant and the auxiliary antioxidant is adjusted compared with Example 6, and the yellowing resistance of the film is reduced. In Examples 15 and 16, the proportion of the main antioxidant and the auxiliary antioxidant in the film is increased, but too much antioxidant reduces the yellowing resistance.
[0120] Combining Comparative Examples 4 to 6 with Example 6, it can be seen that the change in the amount of phosphite intermediate added during synthesis will greatly affect the yellowing resistance of the film. When no phosphite intermediate is added, the yellowing resistance is greatly reduced. Compared with Example 6, when the main antioxidant or the auxiliary antioxidant is used alone or neither is used in Comparative Examples 7 to 9, the color of the film turns yellow significantly. In Comparative Examples 10 to 13, changing the type of antioxidant and reducing the amount both lead to yellowing of the film.
[0121] 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.
[0122] 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 polyvinyl acetal film, characterized in that: The following raw materials are included by weight: 100 parts of modified polyvinyl acetal, 20-0 parts of plasticizer, 0.04-0.6 parts of primary antioxidant, 0.1-1.2 parts of auxiliary antioxidant; The structural formula of the modified polyvinyl acetal is as follows: Among them, the content of structural units with acetal structure is 67-73 mol%, the content of structural units with hydroxyl structure is 26-30 mol%, the content of structural units with vinyl acetate structure is 1-2 mol%, and the content of structural units with phosphite structure is 0-1 mol%.
2. A polyvinyl acetal film according to claim 1, characterized in that: The preparation steps of the modified polyvinyl acetal are as follows: S1. Preparation of reaction solution: dissolving polyvinyl alcohol in pure water and stirring at 95° C. for 3 h to fully dissolve it to obtain a polyvinyl alcohol stock solution with a solid content of 8.0 wt %, mixing butyraldehyde and a phosphite intermediate to obtain a butyraldehyde reaction solution, wherein the mass fraction of the phosphite intermediate relative to butyraldehyde is 0.01 wt % to 0.5 wt %; S2, homogeneous reaction stage: cool the polyvinyl alcohol stock solution to 20°C, then uniformly add hydrochloric acid with a mass concentration of 36% to 38% within 30 minutes, stir for 30 minutes to 40 minutes, then uniformly add butyraldehyde reaction solution within 30 minutes, and continue stirring and reacting for 30 minutes; S3, high temperature aging stage: after the reaction, the temperature was raised to 40°C at 9°C / h, and the reaction was stirred at constant temperature for 2h; S4, washing and drying stage: after the reaction in S3, 15 wt% sodium hydroxide solution is added, stirred for 30 min, the pH is adjusted to neutral, centrifuged, washed, filtered, placed in a blast drying oven, and dried at 40° C. for 4 h to obtain modified polyvinyl acetal; The degree of polymerization of the polyvinyl alcohol is 300 to 3000; The structural formula of the phosphite intermediate is as follows:
3. A polyvinyl acetal film according to claim 2, characterized in that: The preparation steps of the phosphite intermediate are as follows: (1) 2,4-dicumylphenol and toluene are mixed, and after the 2,4-dicumylphenol is completely dissolved, an acid binding agent triethylamine is added, and the mixture is fully mixed, with toluene being the reaction solvent; (2) After mixing, the temperature is raised to 40° C., and under constant temperature stirring, a mixed solution of phosphorus trichloride and toluene is added dropwise in a molar ratio of phosphorus trichloride to 2,4-dicumylphenol of 1:
1. After the addition is complete, the temperature is kept at 40° C. for 1 hour, and then the temperature is slowly raised to 50-70° C. and kept at this temperature for 3 hours to react; (3) After the reaction is completed, the mixture is cooled to room temperature, 1 mol / L sodium hydroxide solution is added to adjust the pH to neutral, the hydrochloride in the reaction system is removed, the solvent toluene is removed by vacuum distillation, and the mixture is dried in vacuo for 4 hours, and then washed, filtered and dried to obtain a phosphite intermediate.
4. A polyvinyl acetal film according to claim 3, characterized in that: The ratio of 2,4-dicumylphenol to toluene is (0.01 mol to 0.03 mol): 50 mL.
5. The polyvinyl acetal film according to claim 3, characterized in that: The molar ratio of the acid-binding agent triethylamine to 2,4-dicumylphenol is 1.1:
1.
6. The polyvinyl acetal film according to claim 3, characterized in that: The ratio of phosphorus trichloride to toluene in the mixed solution of phosphorus trichloride and toluene is (0.01 mol to 0.05 mol): 5 mL.
7. The polyvinyl acetal film according to claim 2, characterized in that: The mass ratio of the polyvinyl alcohol stock solution to the hydrochloric acid in S2 is 25:0.8-1, and the mass ratio of the polyvinyl alcohol stock solution to the butyraldehyde reaction solution is 25:1.2-1.
3.
8. The polyvinyl acetal film according to claim 1, characterized in that: The plasticizer is one of plasticizer 3G7 and plasticizer 3G8.
9. The polyvinyl acetal film according to claim 1, characterized in that: The main antioxidant is one of antioxidant 1098 and antioxidant 1024; The auxiliary antioxidant is one of antioxidant 168, antioxidant 626, antioxidant PEP-36, antioxidant 627 and antioxidant 618.
10. A method for preparing a polyvinyl acetal film according to any one of claims 1 to 9, characterized in that: The following steps are involved: The components in the raw materials are weighed according to the ratio, the main antioxidant and the auxiliary antioxidant are first mixed evenly, and then dissolved in the plasticizer to obtain a mixed solution, the mixed solution is added to the modified polyvinyl acetal, and the polyvinyl acetal film is obtained after melt extrusion through an extruder.