阅读说明：本技术 一种利用固体酸催化制备聚乙烯醇缩丁醛的方法 (Method for preparing polyvinyl butyral by using solid acid catalysis ) 是由 王钧伟 石旵东 张元广 郑学根 崔晓峰 杨森 秦伟 吴秀银 于 2020-11-30 设计创作，主要内容包括：本发明公开了一种利用固体酸催化制备聚乙烯醇缩丁醛的方法,涉及高分子化工技术领域,所述方法包括在水与乙醇的混合溶剂中加入聚乙烯醇、正丁醛,然后加入固体酸催化剂,反应结束后加水,析出分离目标产物；采用水和乙醇的混合溶液作为溶剂,同时使用了固体酸催化剂来代替传统的液体无机酸催化剂,避免了杂离子的引入,提高了产品品质,减小了设备腐蚀。(The invention discloses a method for preparing polyvinyl butyral by utilizing solid acid catalysis, which relates to the technical field of polymer chemical industry, and comprises the steps of adding polyvinyl alcohol and n-butyraldehyde into a mixed solvent of water and ethanol, then adding a solid acid catalyst, adding water after the reaction is finished, and separating out and separating a target product; the mixed solution of water and ethanol is used as a solvent, and the traditional liquid inorganic acid catalyst is replaced by the solid acid catalyst, so that the introduction of impurity ions is avoided, the product quality is improved, and the corrosion of equipment is reduced.)

1. A method for preparing polyvinyl butyral by using solid acid catalysis is characterized in that the method comprises the steps of adding polyvinyl alcohol and n-butyraldehyde into a mixed solvent of water and ethanol, then adding a solid acid catalyst, adding water after reaction is finished, and separating out a target product.

2. The method for preparing polyvinyl butyral by using solid acid catalysis as claimed in claim 1, wherein the mass ratio of polyvinyl alcohol to n-butyraldehyde to the solid acid catalyst is 20:14:1, the volume ratio of ethanol to water in the mixed solvent is 1.2: 1, the reaction temperature is 75 ℃, and the reaction time is 12 hours.

3. The method of claim 2, wherein the solid acid catalyst, solid sulfonated activated carbon catalyst, or solid sulfonated acidic ion exchange resin catalyst.

Technical Field

The invention relates to the technical field of polymer chemical industry, in particular to a method for preparing polyvinyl butyral.

Background

Polyvinyl Butyral (PVB) is a condensation product obtained by reacting n-butyraldehyde with Polyvinyl alcohol (PVA) under the catalysis of strong acid. The polyvinyl butyral molecule contains longer branched chains, has good flexibility, excellent transparency, strong adhesive force, good light resistance, heat resistance, cold resistance, water resistance, film forming property, solubility, miscibility, high tensile strength, impact resistance and the like, and is widely applied to the fields of safety glass interlayers, photovoltaic module packaging films, vacuum aluminized paper, adhesives and the like. With the rapid development of the industries such as automobiles, buildings and the like in China, the demand for high-quality PVB resin is more vigorous, and the demand amount is exponentially increased.

The technology for producing PVB resin in China has a large gap compared with the developed countries. The quality of PVB resin is primarily affected by the manufacturing process and post-processing, in addition to the purity of the raw materials. At present, commercial production processes of PVB resins are basically divided into two types, i.e., a one-step process using polyvinyl acetate and general vinyl ester polymers as raw materials and a two-step process using polyvinyl alcohol (PVA) as a raw material. The production of PVB in China mostly adopts a two-step precipitation method of liquid inorganic acid catalysis, although water is used as a solvent, the production cost is low, the inorganic acid has serious corrosion to equipment, the equipment is easy to damage, the investment is high, the post-treatment must be carried out through the procedures of neutralization, water washing and the like, the catalyst and salt substances generated by the catalyst and the like are removed, the operation is complicated, a large amount of time and water resources are consumed, and a large amount of waste water is generated and needs to be treated. The liquid inorganic acid catalytic method has the main problems that the local speed of the acetal reaction is too high, so that PVB is separated out from a reaction system in a compact block and easily carries impurities such as raw materials, catalysts, solvents and the like; as well as non-uniform intermolecular crosslinking reactions, leading to a reduction in the quality of the PVB product. Therefore, the development of a production technology of high-viscosity and high-quality PVB resin is urgently needed in China, the green degree of the process is improved, the process is simplified, and the cost is reduced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for preparing polyvinyl butyral by using solid acid catalysis, so as to solve the technical problems of poor PVB quality and the like in the prior art.

The invention is realized by the following technical scheme:

the invention provides a method for preparing polyvinyl butyral by using solid acid catalysis, which comprises the steps of adding polyvinyl alcohol and n-butyraldehyde into a mixed solvent of water and ethanol, then adding a solid acid catalyst, adding water after the reaction is finished, and separating out and separating a target product.

Further, the mass ratio of the polyvinyl alcohol to the n-butyraldehyde to the solid acid catalyst is 20:14:1, the volume ratio of ethanol to water in the mixed solvent is 1.2: 1, the reaction temperature is 75 ℃, and the reaction time is 12 hours.

Further, the solid acid catalyst, the solid sulfonated activated carbon catalyst or the solid sulfonated acidic ion exchange resin catalyst.

Compared with the prior art, the invention has the following advantages: the invention provides a method for preparing polyvinyl butyral by using solid acid catalysis, which takes a mixed solution of water and ethanol as a solvent, and solves the problem that PVB is agglomerated and separated out in the traditional reaction process using a water solvent; meanwhile, the solid acid catalyst is used, so that the corrosion problem of equipment is remarkably reduced compared with the traditional liquid inorganic acid catalyst; the reaction adopts a one-step method, the reaction condition is mild, the solvent and the product are easy to separate after the reaction, the process flow is simplified, the industrial cost is reduced, and the pollution to the environment is reduced.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The solid acid catalysts referred to in the following examples are solid sulfonated activated carbon catalysts or solid sulfonated acidic ion exchange resin catalysts.

Wherein: the preparation method of the solid sulfonated active carbon catalyst comprises the following steps: drying activated carbon particles at 110 ℃ for 2 hours, then soaking the activated carbon particles in concentrated sulfuric acid at 130-180 ℃ for sulfonation, washing the sulfonated activated carbon particles to be neutral after 9-14 hours of sulfonation, and drying the sulfonated activated carbon particles to obtain a solid sulfonated activated carbon catalyst;

the preparation method of the solid sulfonated acidic ion exchange resin catalyst comprises the following steps: drying the acidic ion exchange resin at 100 ℃ for 2 hours, then soaking the acidic ion exchange resin in concentrated sulfuric acid at 80-120 ℃ for sulfonation for 8-16 hours, and then washing and drying the acidic ion exchange resin to obtain the sulfonated acidic ion exchange resin catalyst.

Example 1

Dissolving 4g of polyvinyl alcohol in a mixed solvent of ethanol and water (V ethanol: V water: 1.2: 1) under continuous stirring, adding 2.8g of n-butyraldehyde, then adding 0.2g of the prepared solid sulfonated activated carbon catalyst, and reacting for 12 hours under continuous stirring at the reaction temperature of 75 ℃, wherein the n-butyraldehyde reacts with the polyvinyl alcohol to generate polyvinyl butyral, and the acetalization degree of a product is higher than 80%. After the reaction is finished, the reaction liquid is filtered at normal temperature through a funnel, and then the solid sulfonated activated carbon catalyst in the reaction system can be separated from the liquid product, so that the solid sulfonated activated carbon catalyst and the filtrate are obtained. Adding appropriate amount of water into the filtrate to precipitate PVB in solid state from liquid phase, and filtering to obtain solid product PVB and liquid isolate containing ethanol and water. Thus, the catalyst, the product and the solvent can be separated after the acetalation reaction is finished through simple filtration, water addition and filtration steps.

Example 2

Dissolving 4g of polyvinyl alcohol in a mixed solvent of ethanol and water (V ethanol: V water: 1.2: 1) under continuous stirring, adding 2.8g of n-butyraldehyde, then adding 0.3g of the prepared solid sulfonated acidic ion exchange resin catalyst, and reacting for 11 hours under continuous stirring at the reaction temperature of 95 ℃, wherein the n-butyraldehyde reacts with the polyvinyl alcohol to generate the polyvinyl butyral, and the acetalization degree of the product is higher than 70%. After the reaction is finished, the reaction solution is filtered at normal temperature through a funnel, and then the solid sulfonated acidic ion exchange resin catalyst in the reaction system can be separated from the liquid product, so that the solid sulfonated acidic ion exchange resin catalyst and the filtrate are obtained. Adding appropriate amount of water into the filtrate to precipitate PVB in solid state from liquid phase, and filtering to obtain solid product PVB and liquid isolate containing ethanol and water. Thus, the catalyst, the product and the solvent can be separated after the acetalation reaction is finished through simple filtration, water addition and filtration steps.

Example 3

Dissolving 4g of polyvinyl alcohol in a mixed solvent of ethanol and water (V ethanol: V water: 1.2: 1) under continuous stirring, adding 2.8g of n-butyraldehyde, then adding 0.25g of the prepared solid sulfonated acidic ion exchange resin catalyst, and reacting for 10 hours under continuous stirring at the reaction temperature of 70 ℃, wherein the n-butyraldehyde reacts with the polyvinyl alcohol to generate the polyvinyl butyral, and the acetalization degree of a product is higher than 60%. After the reaction is finished, the reaction liquid is filtered at normal temperature through a funnel, and then the solid carbon-based solid acid catalyst in the reaction system can be separated from the liquid product, so that the solid carbon-based solid acid catalyst and the filtrate are obtained. Adding appropriate amount of water into the filtrate to precipitate PVB in solid state from liquid phase, and filtering to obtain solid product PVB and liquid isolate containing ethanol and water. Thus, the catalyst, the product and the solvent can be separated after the acetalation reaction is finished through simple filtration, water addition and filtration steps.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.