A preparation method of polyvinyl butyral resin

Abstract

The present invention provides a preparation method of polyvinyl butyral resin, which is characterized in that: the preparation method comprises the following steps: mixing PVA1799 resin and PVA2699 resin in proportion and dissolving them in an organic solution, heating and stirring at 80-105 °C for 2-2.5 h to prepare a polyvinyl alcohol solution; adding the polyvinyl alcohol solution into a reaction kettle, and then adding at least 1 / 3 of the total amount of organic acid, butyraldehyde and emulsifier into the reaction kettle to form a mixed solution, and stirring the mixed solution for 0.3-0.9 h; cooling to 50-79 °C, and then adding the mixture of the remaining organic acid and n-butyraldehyde, and reacting for 1-1.5 h; stirring at 5-18 °C for 2-2.5 h, heating to 50-55 °C and maintaining for 1-2 h, and drying in vacuum at 55-60 °C for 6-8 h to obtain a PVB product. The preparation process is reasonable, the acetalization rate can be improved, and PVB resin with higher viscosity can be produced.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material production, in particular to a method for preparing polyvinyl butyral resin. Background Art

[0002] In the industrial production process of polyvinyl butyral resin (PVB for short), polyvinyl alcohol (PVA) and butyraldehyde are used, with hydrochloric acid as a catalyst to form the product. The coating formed by PVB has good optical clarity, good weather resistance, and excellent adhesion to various glass surfaces. It is widely used in the automotive and construction industries and has a large market.

[0003] High-viscosity PVB resin has always been a hot topic in current scientific research. High-viscosity PVB resin can not only improve the mechanical properties of related films, but also improve the stability of PVB film.

[0004] At present, my country's demand for PVB is increasing day by day. Compared with other mainstream international brands, domestic high-viscosity PVB resin has certain weaknesses in light transmittance, impact resistance and weather resistance, resulting in most of the domestic market being occupied by imported resins.

[0005] Chinese patent application number: 201810353324.1 discloses a high melt index resin and its preparation method. The high melt index resin comprises PVA1792, PVA2099, n-butyraldehyde, and hydrochloric acid. The mass ratio of PVA1792 to PVA2099 is 1:2.3-4.1, and the mass ratio of the mixture of PVA1792 and PVA2099 to n-butyraldehyde is 1:0.3-0.5. The amount of hydrochloric acid is such that the final concentration of hydrochloric acid in the aqueous solution of the PVA mixture and n-butyraldehyde is 0.8-1.0%. By mixing PVA with a low alcoholysis degree and PVA with a high degree of polymerization, and adding them together without changing other process parameters, PVB with a higher viscosity and a similarly high melt index is produced. This patent utilizes a mixed dissolution of the two resins, using the mixture and n-butyraldehyde as the reaction raw materials, and hydrochloric acid as the reaction catalyst. After the reaction is complete, the high-viscosity PVB is produced by centrifugation, washing, neutralization, and drying. However, the patent uses PVA1792 resin, which contains fewer hydroxyl functional groups than PVA1799. The PVB made from PVA1792 has weaker tear strength and slightly worse viscosity than PVA1799.

[0006] How to design a method for preparing polyvinyl butyral resin with a reasonable preparation process, improve the acetalization rate, and produce a PVB resin with higher viscosity is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0007] To solve the above problems existing in the prior art, the present invention provides a preparation method of polyvinyl butyral resin. The preparation process is reasonable, which can improve the acetalization rate and produce PVB resin with higher viscosity.

[0008] The object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of polyvinyl butyral resin, characterized in that the preparation method comprises the following steps:

[0010] Step S1: Mix PVA1799 resin and PVA2,699 resin in proportion and dissolve them in an organic solution. Heat and stir at 80 - 105 °C for 2 - 2.5 h to prepare a polyvinyl alcohol solution.

[0011] Step S2: Add the polyvinyl alcohol solution into a reaction kettle, and then add at least 1 / 3 of the total amount of organic acid, n-butyraldehyde and emulsifier into the reaction kettle to form a mixed solution, and stir the mixed solution for 0.3 - 0.9 h.

[0012] Step S3: Cool to 50 - 79 °C, and then add the mixture of the remaining organic acid and n-butyraldehyde, and react for 1 - 1.5 h.

[0013] Step S4: Stir at 5 - 18 °C for 2 - 2.5 h, finally heat to 50 - 55 °C and keep for 1 - 2 h, and vacuum dry at 55 - 60 °C for 6 - 8 h to obtain PVB product.

[0014] Preferably, the organic solution is a monohydric organic alcohol; the organic acid is one of formic acid, acetic acid, acrylic acid, benzenesulfonic acid, toluenesulfonic acid or a mixed acid in proportion; the emulsifier is one of sodium dodecylsulfonate, sodium cholate, sodium sulfate or a mixed emulsifier in proportion.

[0015] Improvement to the above technical solution: The mass ratio of PVA1799 resin to PVA2,699 resin is 1:0.5 - 1:5.

[0016] Further improvement to the above technical solution: The volume ratio of the organic solvent to water in the organic solution is 1:5 - 1:15.

[0017] Further improvement to the above technical solution: The mass ratio of the mixture of PVA1799 resin and PVA2,699 resin to the emulsifier is 1:0.010 - 1:0.050.

[0018] Further improvement to the above technical solution: The mass ratio of the mixture of PVA1799 resin and PVA2,699 resin to n-butyraldehyde is 1:0.5 - 1:1.0.

[0019] Further improvement of the above technical solution: The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to the organic acid is 1:0.01 - 1:0.20.

[0020] The advantages and positive effects of the present invention compared with the prior art are as follows:

[0021] 1. The present invention uses organic acid, reducing the environmental pollution caused by inorganic acid;

[0022] 2. The present invention no longer adopts the step of rinsing with a large amount of water in the traditional process, reducing water consumption;

[0023] 3. The present invention realizes the reaction control in parts, improving the overall uniformity of the reaction products;

[0024] 4. The present invention increases the acetalization rate and the viscosity of the product. Description of the Drawings

[0025] Figure 1 is the process flow chart of a preparation method of a polyvinyl butyral resin of the present invention. Detailed Embodiments

[0026] The present invention will be further described in detail below with reference to the drawings:

[0027] See Figure 1 , the detailed embodiments of a preparation method of a polyvinyl butyral resin of the present invention, using PVA1799, PVA2699 and n-butyraldehyde as raw materials, an organic solvent as a chain extender, an organic acid as a catalyst, and also adding an emulsifier. The preparation method includes the following steps:

[0028] Step S1: Mix PVA1799 resin and PVA2699 resin in proportion and dissolve them in an organic solution, and heat and stir at 80 - 105 °C for 2 - 2.5 h to prepare a polyvinyl alcohol solution;

[0029] Step S2: Add the polyvinyl alcohol solution to a reaction kettle, and then add at least 1 / 3 of the total amount of organic acid, n-butyraldehyde and emulsifier to the reaction kettle to form a mixed solution, and stir the mixed solution for 0.3 - 0.9 h;

[0030] Step S3: Cool to 50 - 79 °C, and then add the mixture of the remaining organic acid and n-butyraldehyde, and react for 1 - 1.5 h;

[0031] Step S4: Stir at 5 - 18 °C for 2 - 2.5 h, finally heat to 50 - 55 °C and keep it for 1 - 2 h, and vacuum dry at 55 - 60 °C for 6 - 8 h to obtain a PVB product.

[0032] Preferably, the organic solution is a monohydric organic alcohol; the organic acid is one of formic acid, acetic acid, acrylic acid, benzenesulfonic acid, toluenesulfonic acid or a mixed acid in proportion; the emulsifier is one of sodium dodecyl sulfonate, sodium cholate, sodium sulfate or an emulsifier mixed in proportion.

[0033] Further, the mass ratio of the PVA1799 resin to the PVA2699 resin is 1:0.5 - 1:5; the volume ratio of the organic solvent to water in the organic solution is 1:5 - 1:15; the mass ratio of the mixture of the PVA1799 resin and the PVA2699 resin to the emulsifier is 1:0.010 - 1:0.050; the mass ratio of the mixture of the PVA1799 resin and the PVA2699 resin to the n-butyraldehyde is 1:0.5 - 1:1.0; the mass ratio of the mixture of the PVA1799 resin and the PVA2699 resin to the organic acid is 1:0.01 - 1:0.20.

[0034] The following examples are listed to describe the specific process of the present invention in more detail, but the present invention is not limited to the following examples. Any content that is not substantially changed or adjusted by other professionals in the field according to the present invention still falls within the scope of protection of the present invention.

[0035] Example 1:

[0036] (1) Weigh 50 g of PVA1799 resin and 50 g of PVA2699 resin, add them to 1000 ml of an organic solution with a volume concentration of 20%, heat in a water bath to above 90°C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0037] (2) Add the above polyvinyl alcohol solution to a stirring reaction kettle, add 3 g of organic acid, 20 g of butyraldehyde and 3 g of emulsifier to the reaction kettle, and react well in the stirring kettle for more than 2 h.

[0038] (3) Cool the reaction kettle to 70°C, and dropwise add a mixture of 6 g of organic acid and 40 g of butyraldehyde to the reaction kettle in a dropwise manner, and react for 1 h.

[0039] (4) Cool the reaction kettle to below 15°C while continuing to stir for 2 h, then heat the reaction kettle to 55°C and keep it for 1 h, and dry it under vacuum at 55°C for 8 h to obtain a PVB product.

[0040] Example 2:

[0041] (1) Weigh 40 g of PVA1799 resin and 60 g of PVA2699 resin, add them to 1200 ml of an organic solution with a volume concentration of 30%, heat in a water bath to above 90°C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0042] (2) Add the above polyvinyl alcohol solution to a stirred reactor, add 4g of organic acid, 30g of butyraldehyde and 6g of emulsifier to the reactor, and fully react in the stirred reactor for more than 2h.

[0043] (3) The reactor was cooled to 70°C, and a mixture of 8 g of organic acid and 60 g of butyraldehyde was added dropwise to the reactor for 1 h.

[0044] (4) Cool the reactor to below 15°C while continuing to stir for 2 hours, then heat the reactor to 55°C and maintain for 1 hour, and vacuum dry at 55°C for 8 hours to obtain the PVB product.

[0045] Example 3:

[0046] (1) Weigh 30 g of PVA1799 resin and 70 g of PVA2699 resin and add them to 1500 ml of 40% organic solution, heat in a water bath to above 90 °C, and stir thoroughly for more than 2 h to prepare polyvinyl alcohol solution.

[0047] (2) Add the above polyvinyl alcohol solution to a stirred reactor, add 5g of organic acid, 20g of butyraldehyde and 9g of emulsifier to the reactor, and fully react in the stirred reactor for more than 2h.

[0048] (3) The reactor was cooled to 70°C, and a mixture of 10 g of organic acid and 60 g of butyraldehyde was added dropwise to the reactor for 1 h.

[0049] (4) Cool the reactor to below 15°C while continuing to stir for 2 hours, then heat the reactor to 55°C and maintain for 1 hour, and vacuum dry at 55°C for 8 hours to obtain the PVB product.

[0050] Example 4:

[0051] (1) Weigh 20 g of PVA1799 resin and 80 g of PVA2699 resin and add them to 1000 ml of 20% organic solution, heat in a water bath to above 90 °C, and stir thoroughly for more than 2 h to prepare polyvinyl alcohol solution.

[0052] (2) Add the above polyvinyl alcohol solution to a stirred reactor, add 3g of organic acid, 30g of butyraldehyde and 3g of emulsifier to the reactor, and fully react in the stirred reactor for more than 2 hours.

[0053] (3) The reactor was cooled to 70°C, and a mixture of 6 g of organic acid and 60 g of butyraldehyde was added dropwise to the reactor for 1 h.

[0054] (4) Cool the reaction kettle to below 15°C while continuing to stir for 2 h, then heat the reaction kettle to 55°C and hold for 1 h, and vacuum dry at 55°C for 8 h to obtain the PVB product.

[0055] Example 5:

[0056] (1) Weigh 50 g of PVA1799 resin and 50 g of PVA2699 resin, add them to 1200 ml of an organic solution with a volume concentration of 30%, heat in a water bath to above 90°C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0057] (2) Add the above polyvinyl alcohol solution to a stirring reaction kettle, add 4 g of organic acid, 20 g of butyraldehyde, and 6 g of emulsifier to the reaction kettle, and react in the stirring kettle for more than 2 h.

[0058] (3) Cool the reaction kettle to 70°C, and dropwise add a mixture of 8 g of organic acid and 40 g of butyraldehyde to the reaction kettle by dropping, and react for 1 h.

[0059] (4) Cool the reaction kettle to below 15°C while continuing to stir for 2 h, then heat the reaction kettle to 55°C and hold for 1 h, and vacuum dry at 55°C for 8 h to obtain the PVB product.

[0060] Example 6:

[0061] (1) Weigh 40 g of PVA1799 resin and 60 g of PVA2699 resin, add them to 1500 ml of an organic solution with a volume concentration of 40%, heat in a water bath to above 90°C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0062] (2) Add the above polyvinyl alcohol solution to a stirring reaction kettle, add 5 g of organic acid, 30 g of butyraldehyde, and 9 g of emulsifier to the reaction kettle, and react in the stirring kettle for more than 2 h.

[0063] (3) Cool the reaction kettle to 70°C, and dropwise add a mixture of 10 g of organic acid and 60 g of butyraldehyde to the reaction kettle by dropping, and react for 1 h.

[0064] (4) Cool the reaction kettle to below 15°C while continuing to stir for 2 h, then heat the reaction kettle to 55°C and hold for 1 h, and vacuum dry at 55°C for 8 h to obtain the PVB product.

[0065] Example 7:

[0066] (1) Weigh 30 g of PVA1799 resin and 70 g of PVA2699 resin, add them to 1000 ml of an organic solution with a volume concentration of 20%, heat in a water bath to above 90°C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0067] (2) Add the above polyvinyl alcohol solution to a stirring reaction kettle, add 3 g of organic acid, 20 g of butyraldehyde and 3 g of emulsifier to the reaction kettle, and react in the stirring kettle for more than 2 h.

[0068] (3) Cool the reaction kettle to 70 °C, and dropwise add a mixture of 6 g of organic acid and 40 g of butyraldehyde to the reaction kettle in a dropwise manner, and react for 1 h.

[0069] (4) Cool the reaction kettle to below 15 °C while continuing to stir for 2 h, then heat the reaction kettle to 55 °C and hold for 1 h, and vacuum dry at 55 °C for 8 h to obtain the PVB product.

[0070] Example 8:

[0071] (1) Weigh 20 g of PVA1799 resin and 80 g of PVA2699 resin, add them to 1200 ml of an organic solution with a volume concentration of 30%, heat in a water bath to above 90 °C, and stir well for more than 2 h to prepare a polyvinyl alcohol solution.

[0072] (2) Add the above polyvinyl alcohol solution to a stirring reaction kettle, add 4 g of organic acid, 30 g of butyraldehyde and 6 g of emulsifier to the reaction kettle, and react in the stirring kettle for more than 2 h.

[0073] (3) Cool the reaction kettle to 70 °C, and dropwise add a mixture of 8 g of organic acid and 60 g of butyraldehyde to the reaction kettle in a dropwise manner, and react for 1 h.

[0074] (4) Cool the reaction kettle to below 15 °C while continuing to stir for 2 h, then heat the reaction kettle to 55 °C and hold for 1 h, and vacuum dry at 55 °C for 8 h to obtain the PVB product.

[0075] Key technical points of the present invention:

[0076] Raw materials: By mixing polyvinyl alcohols with different molecular weights in a certain proportion, the preparation of high-viscosity polyvinyl butyral is realized, enriching the preparation sources.

[0077] Catalyst: By using a specific acid catalyst with certain volatility, the problem that a large amount of water flushing is required after the preparation of the conventional catalyst in the past is avoided.

[0078] Process: In the process operation, a feeding method different from the traditional one-time feeding is used to achieve fractional feeding and improve the product quality.

[0079] The present invention utilizes a PVA1799 resin with a high degree of alcoholysis. The PVA molecule contains a relatively large number of hydroxyl groups, thereby increasing the proportion of hydroxyl groups in the PVB resin powder, and further increasing the viscosity and mechanical strength of the resin. In addition, during the mixing process of different substances in the present invention, mixing control is carried out. By using a stirring reactor and other micro-structured reactors, the condensation amount of butyraldehyde at the initial stage of the reaction is controlled, ensuring the critical state of PVB precipitation in the entire solution, and the solution is in a uniform state. At the same time, due to the emulsifying effect of the emulsifier, the macromolecular chains of PVA are fully stretched, making the hydroxyl groups on the molecular chains fully exposed, which is beneficial to the acetalization reaction, improves lipophilicity, and also reduces the load of subsequent reactions. In the subsequent mixing stage, the solution in the critical state accelerates the reaction process of the subsequently added n-butyraldehyde, improves the degree of acetalization and the uniformity of acetal on the molecular surface, and obtains a PVB resin product with a high degree of acetalization.

[0080] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention also fall within the protection scope of the present invention.

Claims

1. A method for preparing polyvinyl butyral resin, characterized in that, The preparation method comprises the following steps: Step S1: Mix PVA1799 resin and PVA2699 resin in proportion and dissolve them in an organic solution. Heat and stir at 80 - 105 °C for 2 - 2.5 h to prepare a polyvinyl alcohol solution; Step S2: Add the polyvinyl alcohol solution to a reaction kettle, then add an organic acid, n-butyraldehyde and an emulsifier accounting for at least 1 / 3 of the total amount to form a mixed solution, and stir the mixed solution for 0.3 - 0.9 h; Step S3: Cool to 50 - 79 °C, then add the mixture of the remaining organic acid and n-butyraldehyde, and react for 1 - 1.5 h; Step S4: Stir at 5 - 18 °C for 2 - 2.5 h, finally heat to 50 - 55 °C and keep for 1 - 2 h, and vacuum dry at 55 - 60 °C for 6 - 8 h to obtain a PVB product; The organic solution is a monohydric organic alcohol; the organic acid is one of formic acid, acetic acid, acrylic acid, benzenesulfonic acid, toluenesulfonic acid or a mixed acid in proportion; the emulsifier is one of sodium dodecyl sulfonate, sodium cholate, sodium sulfate or a mixed emulsifier in proportion.

2. The preparation method of the polyvinyl butyral resin according to claim 1, characterized in that, The mass ratio of PVA1799 resin to PVA2699 resin is 1:0.5 - 1:

5.

3. The preparation method of a polyvinyl butyral resin according to claim 1 or 2, characterized in that, The volume ratio of the organic solvent to water in the organic solution is 1:5 - 1:

15.

4. The preparation method of a polyvinyl butyral resin according to claim 1 or 2, characterized in that, The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to the emulsifier is 1:0.010 - 1:0.

050.

5. The preparation method of a polyvinyl butyral resin according to claim 3, characterized in that, The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to the emulsifier is 1:0.010 - 1:0.

050.

6. The preparation method of a polyvinyl butyral resin according to claim 1 or 2, characterized in that, The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to n-butyraldehyde is 1:0.5 - 1:1.

0.

7. The preparation method of the polyvinyl butyral resin according to claim 5, characterized in that, The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to n-butyraldehyde is 1:0.5 - 1:1.

0.

8. The preparation method of a polyvinyl butyral resin according to claim 7, characterized in that, The mass ratio of the mixture of PVA1799 resin and PVA2699 resin to the organic acid is 1:0.01 - 1:0.20.

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