阅读说明：本技术 一种耐黄变聚乙烯醇缩丁醛树脂的制备方法 (Preparation method of yellowing-resistant polyvinyl butyral resin ) 是由 喻永连 袁港 刘明 徐康林 于 2021-10-27 设计创作，主要内容包括：本发明公开了一种耐黄变聚乙烯醇缩丁醛树脂的制备方法,其特征是：将聚乙烯醇和水加入到溶解釜中,升温至90℃～98℃,搅拌溶解后过滤,再降温至35℃～50℃,投入正丁醛搅拌,得聚乙烯醇/正丁醛混合溶液；将聚乙烯醇/正丁醛混合溶液与盐酸水溶液在温度35～50℃下分别进入管式反应器中反应,再将物料转至温度为35℃～50℃的老化釜中反应,再加入盐酸水溶液,升温至55℃～70℃反应；加入氢氧化钠水溶液使反应液pH=10,过滤、固体物用水洗后干燥,即制得耐黄变聚乙烯醇缩丁醛树脂；采用本发明制得耐黄变聚乙烯醇缩丁醛树脂在200℃的电热恒温鼓风干燥烘箱内烘烤1h仍不发黄,适用于汽车挡风玻璃、建筑安全玻璃等。(The invention discloses a preparation method of yellowing-resistant polyvinyl butyral resin, which is characterized by comprising the following steps: adding polyvinyl alcohol and water into a dissolving kettle, heating to 90-98 ℃, stirring for dissolving, filtering, cooling to 35-50 ℃, adding n-butyl aldehyde, and stirring to obtain a polyvinyl alcohol/n-butyl aldehyde mixed solution; respectively putting the polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution into a tubular reactor for reaction at the temperature of 35-50 ℃, then transferring the materials into an aging kettle at the temperature of 35-50 ℃ for reaction, then adding the hydrochloric acid aqueous solution, and heating to 55-70 ℃ for reaction; adding a sodium hydroxide aqueous solution to ensure that the pH of the reaction solution is =10, filtering, washing the solid with water, and drying to obtain the yellowing-resistant polyvinyl butyral resin; the yellowing-resistant polyvinyl butyral resin prepared by the invention can not be yellow after being baked for 1 hour in an electric heating constant-temperature blast drying oven at the temperature of 200 ℃, and is suitable for automobile windshields, building safety glass and the like.)

1. A preparation method of yellowing-resistant polyvinyl butyral resin is characterized by comprising the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding polyvinyl alcohol and deionized water into a dissolving kettle at normal temperature, heating to 90-98 ℃, stirring and dissolving to obtain a polyvinyl alcohol aqueous solution, filtering, cooling to 35-50 ℃, adding n-butyl aldehyde, and stirring for 10-40 min to obtain a polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding a polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% -1.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 35-50 ℃ within 6-10 min, reacting for 10-20 min, then transferring all materials into an aging kettle with the stirring speed of 70 r/min-100 r/min and the initial temperature of 35-50 ℃, adding the hydrochloric acid aqueous solution with the mass percentage concentration of 20% -30% after reacting for 1h, heating to 55-70 ℃, and finishing the reaction after reacting for 1-2 h to obtain a reaction solution; and adding an aqueous solution of sodium hydroxide to make the pH of the reaction solution =10, filtering, washing the solid with deionized water, and drying to obtain the yellowing-resistant polyvinyl butyral resin.

2. The process for preparing the yellowing-resistant polyvinyl butyral resin as claimed in claim 1, which comprises the steps of:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding 100 parts by mass of polyvinyl alcohol and 670-1330 parts by mass of deionized water into a dissolving kettle at normal temperature, heating to 90-98 ℃, stirring and dissolving to obtain a polyvinyl alcohol aqueous solution, filtering, cooling to 35-50 ℃, adding 50-65 parts by mass of n-butyl aldehyde, and stirring for 10-40 min to obtain a polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

mixing a polyvinyl alcohol/n-butyl aldehyde mixed solution with a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% -1.5% at the temperature of 35-50 ℃ according to the volume ratio of 100: taking 1000-1500 parts by mass of a polyvinyl alcohol/n-butyraldehyde mixed solution and 160-240 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5-1.5% according to a proportion of 15-25, continuously feeding the mixed solution and the hydrochloric acid aqueous solution into a tubular reactor with heating and cooling functions through respective pipelines within 6-10 min, reacting for 10-20 min, then transferring all the materials into an aging kettle with the stirring speed of 70-100 r/min and the initial temperature of 35-50 ℃, adding 5-10 parts by mass of the hydrochloric acid aqueous solution with the mass percentage concentration of 20-30% after reacting for 1h, simultaneously heating to 55-70 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 1-2 h to obtain a reaction solution; and adding an aqueous solution of sodium hydroxide to make the pH of the reaction solution =10, filtering, washing the solid with deionized water, and drying to obtain the yellowing-resistant polyvinyl butyral resin.

3. The process for producing a yellowing-resistant polyvinyl butyral resin as claimed in claim 1 or 2, wherein: the polyvinyl alcohol in the step a is polyvinyl alcohol with the polymerization degree of 1200-2400 and the alcoholysis degree of 92-99%.

4. The process for producing a yellowing-resistant polyvinyl butyral resin as claimed in claim 1 or 2, wherein: in the step a, the polyvinyl alcohol is one of polyvinyl alcohols with the trade names of 1599, 1799 and 2099 provided by Chongqing Chuanwei, Anhui Wei and Ningxia land production.

5. The process for producing a yellowing-resistant polyvinyl butyral resin as claimed in claim 3, wherein: in the step a, the polyvinyl alcohol is one of polyvinyl alcohols with the trade names of 1599, 1799 and 2099 provided by Chongqing Chuanwei, Anhui Wei and Ningxia land production.

Technical Field

The invention belongs to an organic compound and preparation thereof, and relates to a preparation method of anti-yellowing polyvinyl butyral resin. The yellowing-resistant polyvinyl butyral resin prepared by the invention is particularly suitable for the fields of automobile windshields, building safety glass and the like, and is also suitable for ink, paint, adhesive and the like.

Background

Polyvinyl butyral (PVB for short) resin is an important chemical product, contains hydroxyl, polycyclic and acetyl in a molecular structure, has the characteristics of excellent optical performance and good safety performance, and is mainly applied to safety glass interlayer materials; meanwhile, the coating is widely applied to the fields of aviation, automobiles, buildings, photovoltaics, coatings, textiles and the like. However, the use of PVB resins is limited by the problem of residual contaminants (acid and butyraldehyde predominate) that cause yellowing of PVB as it ages and degrades during storage or use. In order to solve the problem, in the existing technology for preparing the PVB resin, CN 111533832A discloses "a yellowing-resistant polyvinyl butyral resin, a preparation method and an application thereof", CN 103865218A discloses "a method for improving yellowing resistance of the PVB resin", and CN 112375165a discloses "a polyvinyl butyral resin and a preparation method thereof", but these existing technologies are complicated in process, need to add an auxiliary additive or increase washing times, and are not conducive to industrial production, and have poor practicability.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a preparation method of yellowing-resistant polyvinyl butyral resin. The invention provides a method for preparing yellowing-resistant polyvinyl butyral resin, which is characterized in that the reaction temperature is increased in the initial stage of preparing polyvinyl butyral by acetalizing polyvinyl alcohol (PVA) and n-butyraldehyde, the acetalization degree of the polyvinyl butyral resin reaches a certain value in a short time, the sticking time of the precipitated resin powder is short, a certain pore is left after incomplete adhesion among the resin powder, and finally the obtained PVB resin powder is formed by agglomerating original particles with smaller particle size, so that the prepared yellowing-resistant polyvinyl butyral resin can not be yellowed after being baked in an electric heating constant-temperature blast drying oven at 200 ℃ for 1 hour, and the yellowing-resistant polyvinyl butyral resin has good ageing resistance and thermal stability.

The content of the invention is as follows: a preparation method of yellowing-resistant polyvinyl butyral resin is characterized by comprising the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding polyvinyl alcohol and deionized water into a dissolving kettle at normal temperature, heating to 90-98 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 35-50 ℃, adding n-butyl aldehyde, and stirring at high speed for 10-40 min to prepare a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding a polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5-1.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 35-50 ℃ within 6-10 min, reacting for 10-20 min, then transferring all the materials into an aging kettle with the stirring speed of 70-100 r/min and the initial temperature of 35-50 ℃, reacting for 1h under the conditions of the stirring speed and the temperature, then (supplementing) adding the hydrochloric acid aqueous solution with the mass percentage concentration of 20-30%, heating to 55-70 ℃ at the heating rate of 1 ℃/4min, and reacting for 1-2 h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

The invention comprises the following steps: the preparation method of the yellowing-resistant polyvinyl butyral resin is characterized by comprising the following better steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding 100 parts by mass of polyvinyl alcohol and 670-1330 parts by mass of deionized water into a dissolving kettle at normal temperature, heating to 90-98 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 35-50 ℃, adding 50-65 parts by mass of n-butyl aldehyde, and stirring at high speed for 10-40 min to prepare a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

mixing a polyvinyl alcohol/n-butyl aldehyde mixed solution with a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% -1.5% at the temperature of 35-50 ℃ according to the volume ratio of 100: taking 1000-1500 parts by mass of a polyvinyl alcohol/n-butyraldehyde mixed solution and 160-240 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% -1.5%, continuously feeding the polyvinyl alcohol/n-butyraldehyde mixed solution and the hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% -1.5% into a tubular reactor with heating and cooling functions within 6-10 min, reacting for 10-20 min, transferring all the materials into an aging kettle with the stirring speed of 70-100 r/min and the initial temperature of 35-50 ℃, reacting for 1h under the conditions of the stirring speed and the temperature, adding (supplementing) 5-10 parts by mass of the hydrochloric acid aqueous solution with the mass percentage concentration of 20% -30%, heating to 55-70 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction for 1-2 h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

The invention comprises the following steps: the polyvinyl alcohol in the step a is preferably polyvinyl alcohol with the polymerization degree of 1200-2400 and the alcoholysis degree of 92-99%.

The invention comprises the following steps: in the step a, the polyvinyl alcohol can be one of polyvinyl alcohols with the brands (or called models) of 1599, 1799 and 2099 provided by Chongqing Chuanwei, Anhui Wei and Ningxia geon.

Compared with the prior art, the invention has the following characteristics and beneficial effects:

(1) according to the method for preparing the yellowing-resistant polyvinyl butyral resin, the acetalization degree reaches a certain value in a short time by increasing the initial reaction temperature, the separated resin powder is short in sticky time, and a certain pore is left after incomplete adhesion among the resin powder, so that the PVB resin powder with a loose porous structure is finally obtained;

(2) by adopting the method, the reaction temperature is increased in the initial stage of preparing the polyvinyl butyral by acetalizing polyvinyl alcohol (PVA for short) and n-butyraldehyde, the acetalization degree of the polyvinyl butyral reaches a certain value in a short time, the sticking time of the precipitated resin powder is short, a certain pore is left after incomplete adhesion among the resin powders, the finally obtained PVB resin powder is formed by aggregating original particles with small particle size, and the porous loose structure is beneficial to washing out impurities in the product in the washing process, so that the yellowing resistance of the product is improved;

(3) the preparation method disclosed by the invention is simple in preparation process, simple and convenient in working procedure and easy to operate, and the prepared anti-yellowing polyvinyl butyral resin is PVB resin with a loose structure, can be applied to the fields of automobile windshields, building safety glass and the like, and is high in practicability.

Drawings

FIG. 1 and FIG. 2 are photographs of the surface morphology of the yellowing-resistant polyvinyl butyral resin under a scanning electron microscope, which are obtained in example 1 of the present invention;

FIGS. 3 and 4 are photographs showing the surface morphology of the polyvinyl butyral resin obtained in comparative example 1 under a scanning electron microscope;

FIG. 5 is a photograph showing the yellowing of the polyvinyl butyral resin as a result of visual observation after a yellowing test of the polyvinyl butyral resin as a resin having yellowing resistance obtained in example 1 of the present invention;

FIG. 6 is a photograph showing the polyvinyl butyral resin obtained in comparative example 1 as observed with the naked eye after being subjected to a yellowing test.

Detailed Description

The following examples are intended to further illustrate the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims appended hereto.

Example 1:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 1000g of deionized water into a dissolving kettle at normal temperature, heating to 95 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 40 ℃, adding 58g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; 1158g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 185g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% are continuously fed into a tubular reactor with heating and cooling functions through respective pipelines at 40 ℃ within 8min to react for 20min, then all the materials are transferred into an aging kettle with the stirring speed of 100r/min and the initial temperature of 40 ℃, 9.4g of the hydrochloric acid aqueous solution with the mass percentage concentration of 20% is supplemented after the reaction is carried out for 1h under the condition, the temperature is increased to 65 ℃ at the temperature increasing rate of 1 ℃/4min, and the reaction is finished after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Example 2:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 900g of deionized water into a dissolving kettle at normal temperature, heating to 93 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 45 ℃, adding 61g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; continuously feeding 1061g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 170g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% into a tubular reactor with heating and cooling functions through respective pipelines at 45 ℃ within 8min for reaction for 20min, then transferring all the materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 45 ℃, after reacting for 1h under the conditions, supplementing 10g of hydrochloric acid aqueous solution with the mass percentage concentration of 20%, simultaneously heating to 65 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Example 3:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 900g of deionized water into a dissolving kettle at normal temperature, heating to 95 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 35 ℃, adding 61g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; continuously feeding 1061g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 170g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% into a tubular reactor with heating and cooling functions through respective pipelines at 35 ℃ within 8min for reaction for 20min, then transferring all the materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 35 ℃, after reacting for 1h under the conditions, supplementing 6.9g of hydrochloric acid aqueous solution with the mass percentage concentration of 25%, simultaneously heating to 60 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Example 4:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 850g of deionized water into a dissolving kettle at normal temperature, heating to 96 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 40 ℃, adding 62g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; continuously feeding 1012g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 162g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% into a tubular reactor with heating and cooling functions through respective pipelines at 40 ℃ within 8min for reaction for 20min, then transferring all materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 40 ℃, after reacting for 1h under the conditions, supplementing 6.6g of hydrochloric acid aqueous solution with the mass percentage concentration of 25%, simultaneously heating to 68 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Example 5:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 910g of deionized water into a dissolving kettle at normal temperature, heating to 96 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 45 ℃, adding 59g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; continuously feeding 1069g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 171g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% into a tubular reactor with heating and cooling functions through respective pipelines at 45 ℃ within 8min for reaction for 20min, then transferring all the materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 45 ℃, after reacting for 1h under the conditions, supplementing 6.3g of hydrochloric acid aqueous solution with the mass percentage concentration of 30%, simultaneously heating to 60 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Example 6:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps: adding 100g of polyvinyl alcohol and 910g of deionized water into a dissolving kettle at normal temperature, heating to 95 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 50 ℃, adding 63g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; 1073g of the polyvinyl alcohol/n-butyraldehyde mixed solution and 172g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% are continuously fed into a tubular reactor with heating and cooling functions through respective pipelines at 50 ℃ within 8min to react for 20min, then all the materials are transferred into an aging kettle with the stirring speed of 100r/min and the initial temperature of 50 ℃, after the reaction is carried out for 1h under the condition, 6.3g of hydrochloric acid aqueous solution with the mass percentage concentration of 30% is supplemented, the temperature is increased to 70 ℃ at the same time at the temperature rising rate of 1 ℃/4min, and the reaction is finished after 2 h; and adding a proper amount of sodium hydroxide solution to ensure that the pH of the reaction solution is 10, washing with deionized water, centrifuging and drying to obtain the white powdery yellowing-resistant polyvinyl butyral resin.

Comparative example 1:

the difference compared to example 1 is only in the initial temperature of the reaction.

The preparation method of the polyvinyl butyral resin of the present example comprises the steps of: adding 100g of polyvinyl alcohol and 1000g of deionized water into a dissolving kettle at normal temperature, heating to 95 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 40 ℃, adding 58g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; cooling the polyvinyl alcohol/n-butyraldehyde mixed solution to 15 ℃, taking 1158g of the mixed solution and 185g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% to continuously enter a tubular reactor with heating and cooling functions through respective pipelines at 15 ℃ within 8min, reacting for 20min, then transferring all the materials to an aging kettle with the stirring speed of 100r/min and the initial temperature of 15 ℃, reacting for 1h under the condition, supplementing 9.4g of hydrochloric acid aqueous solution with the mass percentage concentration of 20%, simultaneously heating to 65 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; adding a proper amount of sodium hydroxide solution to ensure that the pH value of the reaction solution is 10, then washing the reaction solution by using deionized water, centrifuging and drying the reaction solution to obtain the white powdery polyvinyl butyral resin.

Comparative example 2:

the difference compared to example 2 is only in the initial temperature of the reaction.

The preparation method of the polyvinyl butyral resin of the present example comprises the steps of: adding 100g of polyvinyl alcohol and 900g of deionized water into a dissolving kettle at normal temperature, heating to 93 ℃, stirring to completely dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 45 ℃, adding 61g of n-butyl aldehyde, and stirring at high speed for 30min to obtain a uniform polyvinyl alcohol/n-butyl aldehyde mixed solution; cooling the polyvinyl alcohol/n-butyraldehyde mixed solution to 20 ℃, taking 1061g and 170g of hydrochloric acid aqueous solution with the mass percentage concentration of 1.0%, continuously feeding the mixture and the hydrochloric acid aqueous solution into a tubular reactor with heating and cooling functions through respective pipelines at 20 ℃ within 8min, reacting for 20min, then transferring all the materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 20 ℃, reacting for 1h under the condition, supplementing 10g of hydrochloric acid aqueous solution with the mass percentage concentration of 20%, simultaneously heating to 65 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2 h; adding a proper amount of sodium hydroxide solution to ensure that the pH value of the reaction solution is 10, then washing the reaction solution by using deionized water, centrifuging and drying the reaction solution to obtain the white powdery polyvinyl butyral resin.

The technical index tables of the polyvinyl butyral resins obtained in examples 1 to 6 and comparative examples 1 and 2 are as follows:

the surface morphology of the PVB resins prepared in example 1 and comparative example 1 were characterized by scanning electron microscopy. The test results are shown in FIGS. 1-4.

The polyvinyl butyral resin (abbreviated as PVB resin) prepared in example 1 and comparative example 1 is subjected to a yellowing test, namely, a prepared PVB resin sample (1.500 +/-0.001) g is weighed, the sample is flatly laid on the surface of float white glass with the thickness of 2mm and the thickness of 5cm by 5cm, the float white glass is placed into an electrothermal constant-temperature blast drying oven at 200 ℃ to be baked for 1 hour, the number of the samples is not less than 2, and after 1 hour, the samples are taken out to be cooled and then are observed under sunlight or an incandescent lamp by naked eyes to determine whether the samples turn yellow or not. The test results are shown in FIGS. 5-6.

As can be seen from fig. 1 to 4 and fig. 5 to 6, the surface structure of the PVB resin prepared in example 1 is loose and porous, and does not turn yellow after being baked at 200 ℃ for 1 hour, whereas the surface structure of the PVB resin prepared in comparative example 1 is dense and turns yellow after being baked at 200 ℃ for 1 hour. The protocol of example 1 is superior to that of comparative example 1.

Example 7:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding polyvinyl alcohol and deionized water into a dissolving kettle at normal temperature, heating to 90 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 35 ℃, adding n-butyl aldehyde, and stirring at high speed for 40min to prepare a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding a polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 35 ℃ within 10min for reaction for 20min, then transferring all materials into an aging kettle with the stirring speed of 70r/min and the initial temperature of 35 ℃ (under the conditions of the stirring speed and the temperature) for reaction for 1h, then (complementarily) adding the hydrochloric acid aqueous solution with the mass percentage concentration of 20% (simultaneously at the heating rate of 1 ℃/4 min) for heating to 55 ℃, and finishing the reaction for 2h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

Example 8:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding polyvinyl alcohol and deionized water into a dissolving kettle at normal temperature, heating to 98 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 50 ℃, adding n-butyl aldehyde, and stirring at high speed for 10min to prepare a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding a polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution with the mass percentage concentration of 1.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 50 ℃ within 6min for reaction for 10min, then transferring all materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 50 ℃ (under the conditions of the stirring speed and the temperature) for reaction for 1h, then (complementarily) adding the hydrochloric acid aqueous solution with the mass percentage concentration of 30% (simultaneously at the heating rate of 1 ℃/4 min) for heating to 70 ℃, and finishing the reaction for 1h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

Example 9:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding polyvinyl alcohol and deionized water into a dissolving kettle at normal temperature, heating to 94 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 43 ℃, adding n-butyl aldehyde, and stirring at high speed for 25min to obtain a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding a polyvinyl alcohol/n-butyraldehyde mixed solution and a hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 43 ℃ within 8min for reaction for 15min, then transferring all materials into an aging kettle with the stirring speed of 85r/min and the initial temperature of 43 ℃ (under the conditions of the stirring speed and the temperature) for reaction for 1h, then (complementarily) adding the hydrochloric acid aqueous solution with the mass percentage concentration of 25% (simultaneously at the heating rate of 1 ℃/4 min) for heating to 63 ℃, and finishing the reaction for 1.5h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

Example 10:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding 100 parts by mass of polyvinyl alcohol and 670 parts by mass of deionized water into a dissolving kettle at normal temperature, heating to 90 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 35 ℃, adding 50 parts by mass of n-butyl aldehyde, and stirring at high speed for 40min to obtain a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

respectively continuously feeding 820 parts by mass of a polyvinyl alcohol/n-butyraldehyde mixed solution and 205 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 0.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 35 ℃ within 10min for reaction for 20min, then transferring all the materials into an aging kettle with the stirring speed of 70r/min and the initial temperature of 35 ℃ (under the conditions of the stirring speed and the temperature) for reaction for 1h, then (supplementing) 5 parts by mass of the hydrochloric acid aqueous solution with the mass percentage concentration of 20%, simultaneously heating to 55 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 2h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

Example 11:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding 100 parts by mass of polyvinyl alcohol and 1330 parts by mass of deionized water into a dissolving kettle at normal temperature, heating to 98 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 50 ℃, adding 65 parts by mass of n-butyl aldehyde, and stirring at high speed for 10min to prepare a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

continuously feeding 1495 parts by mass of a polyvinyl alcohol/n-butyraldehyde mixed solution and 225 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 1.5% into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 50 ℃ within 6min, reacting for 10min, then transferring all the materials into an aging kettle with the stirring speed of 100r/min and the initial temperature of 50 ℃, reacting for 1h (under the conditions of the stirring speed and the temperature), then adding 10 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 30%, heating to 70 ℃ at the heating rate of 1 ℃/4min, and finishing the reaction after 1h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

Example 12:

a preparation method of yellowing-resistant polyvinyl butyral resin comprises the following steps:

a. preparation of a polyvinyl alcohol/n-butyraldehyde mixed solution:

adding 100 parts by mass of polyvinyl alcohol and 1000 parts by mass of deionized water into a dissolving kettle at normal temperature, heating to 94 ℃, stirring (completely) to dissolve the polyvinyl alcohol into a polyvinyl alcohol aqueous solution, filtering, cooling to 42 ℃, adding 58 parts by mass of n-butyl aldehyde, and stirring at high speed for 25min to obtain a (uniform) polyvinyl alcohol/n-butyl aldehyde mixed solution;

b. preparing yellowing-resistant polyvinyl butyral resin:

1158 parts by mass of a polyvinyl alcohol/n-butyraldehyde mixed solution and 185 parts by mass of a hydrochloric acid aqueous solution with the mass percentage concentration of 1.0% are continuously fed into a tubular reactor with heating and cooling functions through respective pipelines at the temperature of 42 ℃ within 8min to react for 15min, then all the materials are transferred into an aging kettle with the stirring speed of 85r/min and the initial temperature of 42 ℃, and after reaction for 1h (under the conditions of the stirring speed and the temperature), 7.5 parts by mass of the hydrochloric acid aqueous solution with the mass percentage concentration of 25% are added (supplemented), and the temperature is increased to 63 ℃ at the heating rate of 1 ℃/4min, and the reaction is finished after 1.5h to obtain a reaction solution; then, an appropriate amount of aqueous sodium hydroxide solution is added to adjust the pH of the reaction solution to 10, the mixture is filtered, the solid is washed with deionized water, and then dried (for example, by drying, centrifugal drying, etc.), thereby obtaining (white powder) yellowing-resistant polyvinyl butyral resin.

In the above embodiment: the polyvinyl alcohol in the step a is polyvinyl alcohol with the polymerization degree of 1200-2400 and the alcoholysis degree of 92-99%.

In the above embodiment: in the step a, the polyvinyl alcohol can be one of polyvinyl alcohols with the brands (or called models) of 1599, 1799 and 2099 provided by Chongqing Chuanwei, Anhui Wei and Ningxia geon.

In the above embodiment: any range of process parameters (temperature, time, concentration, etc.) and component amounts in each step can be used.

In the above embodiment: the percentages used, not specifically indicated, are percentages by weight or known to those skilled in the art; the proportions used, not specifically noted, are mass (weight) proportions; the parts by mass (by weight) may all be grams or kilograms.

The present invention and the technical contents not specifically described in the above examples are the same as those of the prior art, and the raw materials are all commercially available products.

The present invention is not limited to the above-described embodiments, and the present invention can be implemented with the above-described advantageous effects.