Polyvinyl butyral with sound insulation performance and preparation method thereof
阅读说明：本技术 一种具有隔音性能的聚乙烯醇缩丁醛及其制备方法 (Polyvinyl butyral with sound insulation performance and preparation method thereof ) 是由 不公告发明人 于 2021-09-18 设计创作，主要内容包括：本发明涉及高分子材料制备技术领域,具体涉及一种具有隔音性能的聚乙烯醇缩丁醛及其制备方法。所述聚乙烯醇缩丁醛,按照重量份数计,包括如下原料：聚乙烯醇30-35份,正丁醛16-19份,催化剂4-6份和表面活性剂0.18-0.3份,所述聚乙烯醇为高聚合度聚乙烯醇和低聚合度聚乙烯醇的混合物,所述高聚合度聚乙烯醇的聚合度为2000-2600,所述低聚合度聚乙烯醇的聚合度为500-800。本发明具有羟基含量低、隔音效果和光学性能优异的优点。(The invention relates to the technical field of preparation of high polymer materials, in particular to polyvinyl butyral with sound insulation performance and a preparation method thereof. The polyvinyl butyral comprises the following raw materials in parts by weight: 30-35 parts of polyvinyl alcohol, 16-19 parts of n-butyraldehyde, 4-6 parts of catalyst and 0.18-0.3 part of surfactant, wherein the polyvinyl alcohol is a mixture of polyvinyl alcohol with high polymerization degree and polyvinyl alcohol with low polymerization degree, the polymerization degree of the polyvinyl alcohol with high polymerization degree is 2600-2000, and the polymerization degree of the polyvinyl alcohol with low polymerization degree is 800-500. The invention has the advantages of low hydroxyl content, sound insulation effect and excellent optical performance.)
1. The polyvinyl butyral with sound insulation performance is characterized by comprising the following raw materials in parts by weight: 30-35 parts of polyvinyl alcohol, 16-19 parts of n-butyraldehyde, 4-6 parts of catalyst and 0.18-0.3 part of surfactant, wherein the polyvinyl alcohol is a mixture of polyvinyl alcohol with high polymerization degree and polyvinyl alcohol with low polymerization degree, the polymerization degree of the polyvinyl alcohol with high polymerization degree is 2600-2000, and the polymerization degree of the polyvinyl alcohol with low polymerization degree is 800-500.
2. The polyvinyl butyral according to claim 1, characterized in that the catalyst is an acid-based catalyst, preferably at least one of hydrochloric acid, sulfuric acid and maleic acid; the mass ratio of the high-polymerization-degree polyvinyl alcohol to the low-polymerization-degree polyvinyl alcohol is 10-11: 1-2; the surfactant comprises at least one of dodecylbenzene sulfonic acid, sodium dodecyl sulfate and sodium dodecyl sulfate.
3. A process for producing polyvinyl butyral as defined in claim 1 or 2, comprising the steps of:
(1) adding polyvinyl alcohol into water, and heating to dissolve the polyvinyl alcohol to obtain a polyvinyl alcohol solution;
(2) adding a surfactant and a catalyst into a polyvinyl alcohol solution to obtain a mixture A;
(3) adding n-butyraldehyde into the mixture A, and reacting to obtain a PVB crude product;
(4) and (3) washing the PVB crude product to be neutral, adding alkali, washing for the second time, centrifuging and drying to obtain the PVB.
4. The preparation method according to claim 3, wherein in the step (1), the polyvinyl alcohol is added into water and soaked for more than 0.5h, the temperature is raised to 90-99 ℃, the polyvinyl alcohol is dissolved for 1.5-2h, and the temperature is kept for 1.5-2h after the polyvinyl alcohol is dissolved, so that 8-11% polyvinyl alcohol solution is prepared.
5. The method according to claim 3, wherein the surfactant and the catalyst are added when the temperature of the polyvinyl alcohol solution is reduced to 8-12 ℃ in the step (2).
6. The preparation method according to claim 3, wherein the mixture A is cooled to 7-10 ℃ in the step (3) and added with n-butyraldehyde for 6-10 min.
7. The method according to claim 3, wherein the n-butyraldehyde is added in the step (3) and then the low-temperature keeping, the temperature raising and the high-temperature keeping are performed in this order.
8. The preparation method according to claim 7, wherein the low temperature holding time is 1-1.5 h; the temperature rise is 66-68 ℃, and the temperature rise time is 2-3 h; the high-temperature heat preservation time is 2-3 h.
9. The preparation method according to claim 3, wherein the n-butyraldehyde is added in the step (3) and then reacts to generate phase change, the temperature is kept for 1-1.5h after the phase change, then the temperature is raised to 66-68 ℃ within 2-3h, the temperature is kept for 2-3h at 66-68 ℃, the pH is adjusted to 3.8-4.1, the temperature is kept for 25-40min, and a PVB crude product is obtained after the reaction.
10. The preparation method according to claim 3, wherein the pH is adjusted to 11-13 by adding a base in the step (4), and the pH is adjusted to 8-10 by two-time water washing after 1-1.5h of stabilization.
Technical Field
The invention relates to the technical field of preparation of high polymer materials, in particular to polyvinyl butyral with sound insulation performance and a preparation method thereof.
Background
Polyvinyl Butyral (PVB) is a product of condensation of Polyvinyl alcohol and butyraldehyde under acid catalysis. The PVB molecule contains longer branched chain, so that the PVB has good flexibility, low glass transition temperature and high tensile strength and impact strength. PVB has excellent transparency, good solubility, good light resistance, water resistance, heat resistance, cold resistance and film forming property. The functional group contained in the copolymer can perform various reactions such as saponification of phthalidyl, acetification and sulfonation of hydroxyl, and has high adhesion to materials such as glass and metal (especially aluminum). Therefore, the resin is widely applied to the fields of manufacturing laminated safety glass, printing ink, adhesive, ceramic stained paper, aluminum foil paper, electrical equipment materials, glass fiber reinforced plastic products, fabric treating agents and the like, and becomes an indispensable synthetic resin material.
In recent years, with the rapid development of the automobile industry, the building industry and the solar photovoltaic industry, PVB resins have been developed rapidly. The automotive front windshield glass basically uses PVB laminated glass, and the national relevant standards stipulate that safety glass must be used for automotive door windows, the automotive front windshield glass should use the laminated glass, and other automotive windows can use toughened glass. The increasing demand of the automobile industry for PVB is one of the important reasons for the increase of the total amount of PVB films in China.
The sound is a vibration wave, the audible frequency of human ears is 20-20000 Hz, and the particularly sensitive frequency is 1000-4000 Hz. The terminal customer of sound-proof film application area is more and more respecting the function of car and architectural glass noise reduction, also the key consideration safety factor simultaneously, because noise pollution influences people's life and operational environment's travelling comfort, and noise reduction is a very important index.
In the face of increasing PVB sound-insulating film requirements, the sound-insulating resin required for producing the sound-insulating film is more and more required, and accelerating the production of PVB sound-insulating resin and the development of application technology and upgrading optimization are just urgent requirements.
To reduce the noise effect, there are several main approaches: the sound source is prevented from being generated, the transmission medium is isolated, and the vibration of sound is reduced. The sound insulation method adopted by people aiming at the approaches comprises the following steps: increasing the thickness of the glass or increasing the number of layers of the film leads to increased cost and wasted energy.
For sound-damping PVB film, the performance of the sound-damping resin is a critical factor affecting the film performance. The sound insulation PVB film generally realizes sound insulation performance by using a multi-layer compounding technology and changing the structure of different layers of PVB resin or the ratio of PVB plasticizer.
Chinese patent application CN107323056A discloses a three-layer PVB film with sound insulation performance and its preparation method, the three-layer PVB film is composed of a lower layer a, a middle layer B and an upper layer C by three layers of resin films, the middle layer B includes by mass percent: 30-60% of modified PVB resin powder and 70-40% of plasticizer, wherein the lower layer A and the upper layer C comprise the following components in percentage by mass: 60-80% of modified PVB resin powder and 20-40% of plasticizer, wherein the modified PVB resin powder comprises the following components in percentage by mass: 7.5-10.0 wt% of polyvinyl alcohol; 3.0 to 10.0 weight percent of n-butyraldehyde; 1.0-6.0 wt% of hydrochloric acid; 0.01-0.10 wt% of surfactant; the balance being pure water. The preparation method comprises the following steps: the preparation of PVB resin powder and the preparation of three-layer PVB film are improved. The three-layer PVB film provided by the invention has a noise function in the range of 1000-4000Hz when being applied to laminated glass, and the sound insulation effect is improved by 3-5 dB. However, the preparation process of the invention is complex, which leads to increased cost and waste of resources.
In addition, increasing the plasticizer ratio to adjust the mechanical factors of different PVB film layers has the following risks: the mechanical property of the film is reduced, the aging resistance is reduced, and the plasticizer is separated out.
Therefore, in order to improve the quality of the sound-insulating PVB film, the performance of the film resin needs to be improved, and the problems of reduction of mechanical properties, precipitation of a plasticizer and the like are avoided.
Therefore, it is very necessary to develop a polyvinyl butyral having soundproof property and a method for preparing the same, which can solve the above technical problems.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide polyvinyl butyral with sound insulation performance and a preparation method thereof, and the main content is to change the ratio of groups in PVB resin and the molecular weight distribution of the PVB resin, increase the ratio of acetate groups in PVB molecules (the content of the acetate groups in the PVB is the total amount of the groups minus the total amount of hydroxyl groups and butyraldehyde groups), and greatly improve the compatibility of the PVB resin and a plasticizer, so that the flexibility of a film is improved, and the sound insulation performance of the PVB film is enhanced, but the mechanical properties such as the tensile strength and the like of the PVB film cannot be obviously influenced by the increase of the ratio of the plasticizer.
By appropriately increasing the molecular weight distribution of the PVB resin, the presence of small amounts of low molecular weight molecules in the PVB can serve as internal plasticization. The high molecular weight component provides excellent mechanical properties and the low molecular weight component provides excellent processability. After the sound insulation PVB resin is made and the film is extruded, infusible crystal points can not be formed, so that the film casting processing is more stable.
The PVB resin has uniform and fine particle size, better compatibility with a plasticizer and processability, simple preparation method and suitability for a sound insulation film sound insulation layer.
The invention is realized by the following technical scheme:
the polyvinyl butyral with sound insulation performance comprises the following raw materials in parts by weight: 30-35 parts of polyvinyl alcohol, 16-19 parts of n-butyraldehyde, 4-6 parts of catalyst and 0.18-0.3 part of surfactant, wherein the polyvinyl alcohol is a mixture of polyvinyl alcohol with high polymerization degree and polyvinyl alcohol with low polymerization degree, the polymerization degree of the polyvinyl alcohol with high polymerization degree is 2600-2000, and the polymerization degree of the polyvinyl alcohol with low polymerization degree is 800-500.
Preferably, the degree of polymerization of the high-polymerization-degree polyvinyl alcohol is 2600, and the degree of polymerization of the low-polymerization-degree polyvinyl alcohol is 800.
Preferably, the degree of alcoholysis of the polyvinyl alcohol is from 85 to 88%.
Preferably, the catalyst is an acid catalyst.
More preferably, the acid catalyst is at least one of hydrochloric acid, sulfuric acid, and maleic acid.
More preferably, the mass concentration of the hydrochloric acid is 30-35%.
Preferably, the mass ratio of the polyvinyl alcohol with high polymerization degree to the polyvinyl alcohol with low polymerization degree is 10-11: 1-2.
Preferably, the surfactant comprises at least one of dodecylbenzene sulfonic acid, sodium dodecyl sulfate, and sodium dodecyl sulfate.
The invention also relates to a preparation method of the polyvinyl butyral, which comprises the following steps:
(1) adding polyvinyl alcohol into water, and heating to dissolve the polyvinyl alcohol to obtain a polyvinyl alcohol solution;
(2) adding a surfactant and a catalyst into a polyvinyl alcohol solution to obtain a mixture A;
(3) adding n-butyraldehyde into the mixture A, and reacting to obtain a PVB crude product;
(4) and (3) washing the PVB crude product to be neutral, adding alkali, washing for the second time, centrifuging and drying to obtain the PVB.
According to the invention, the surfactant and the catalyst are added firstly, and then the n-butyl aldehyde is added, so that the polyvinyl alcohol and the catalyst are uniformly dispersed before reaction, the reaction with the n-butyl aldehyde is facilitated, and meanwhile, the product is uniformly dispersed.
Preferably, in the step (1), the polyvinyl alcohol is added into water to be soaked for more than 0.5h, the temperature is raised to 90-99 ℃, the polyvinyl alcohol is dissolved for 1.5-2h, and the temperature is kept for 1.5-2h after the polyvinyl alcohol is dissolved, so that 8-11% polyvinyl alcohol solution is prepared.
Preferably, the surfactant and the catalyst are added when the temperature of the polyvinyl alcohol solution in the step (2) is reduced to 8-12 ℃.
Preferably, in the step (3), the temperature of the mixture A is reduced to 7-10 ℃, and n-butyraldehyde is added for 6-10 min.
When the n-butyraldehyde is added, the temperature is controlled below 10 ℃, the reaction rate is controlled, and the phenomenon that the reaction is too fast and the resin particles become coarse is prevented.
Preferably, after the n-butyraldehyde is added in the step (3), the procedures of low-temperature heat preservation, temperature rise and high-temperature heat preservation are sequentially carried out.
Preferably, the low-temperature heat preservation time is 1-1.5 h; the temperature rise is 66-68 ℃, and the temperature rise time is 2-3 h; the high-temperature heat preservation time is 2-3 h.
The temperature rise time is controlled to be 2-3 hours, so that the reaction is uniformly and slowly carried out, and the obtained resin has uniform and fine particle size. The highest reaction temperature of the resin is not more than 70 ℃, and the resin is prevented from caking.
Preferably, the n-butyraldehyde is added in the step (3) and then reacts to generate phase change, the temperature is kept for 1-1.5h after the phase change, then the temperature is raised to 66-68 ℃ within 2-3h, the temperature is kept for 2-3h at 66-68 ℃, the pH is adjusted to 3.8-4.1, the temperature is kept for 25-40min, and a PVB crude product is obtained after the reaction.
The phase change in the step (3) means that n-butyraldehyde is added and then stirred for reaction, when the stirring paddle can stir the solution system, the solution is not sticky and colloidal any more, and the liquid level can form a vortex at the position of the stirring paddle, namely the phase change is generated. I.e. phase transition, means a change from a viscous gel to a solution system.
Preferably, in the step (4), alkali is added to adjust the pH to 11-13, and after 1-1.5h of stabilization, the pH is washed twice by water to 8-10.
More preferably, the preparation method comprises the following steps:
(1) adding polyvinyl alcohol into water, soaking for more than 0.5h, heating to 90-99 ℃, dissolving for 1.5-2h, and keeping the temperature for 1.5-2h after dissolving to prepare 8-11% polyvinyl alcohol solution;
(2) when the temperature of the polyvinyl alcohol solution is reduced to 8-12 ℃, adding a surfactant and a catalyst to obtain a mixture A;
(3) cooling the mixture A to 7-10 ℃, adding n-butyraldehyde to react, wherein the adding time is 6-10min (namely, the n-butyraldehyde is added within 6-10 min), phase transformation occurs, the temperature is kept for 1-1.5h after the phase transformation, then the temperature is raised to 66-68 ℃ within 2-3h, the temperature is kept for 2-3h at 66-68 ℃, the pH is adjusted to 3.8-4.1, the temperature is kept for 25-40min, and a PVB crude product is obtained after the reaction;
(4) and (3) washing the PVB crude product to be neutral, adding alkali to adjust the pH value to 11-13, stabilizing for 1-1.5h, washing for the second time until the pH value is 8-10, centrifuging and drying to obtain the PVB.
The invention has the beneficial effects that:
(1) the PVB prepared by the method has the characteristics of low hydroxyl content and high acetate group content, and has excellent compatibility with a plasticizer when the sound-insulating PVB film is prepared, the sound-insulating PVB film is extruded when the proportion of the plasticizer reaches 60%, the sound-insulating PVB film does not have the plasticizer separated out, and the sound-insulating PVB film is soft and has good sound-insulating performance.
(2) The PVB resin prepared by the method has the characteristics of small particle size, uniform particles and good transparency of PVB resin solution.
(3) The PVB resin prepared by the invention has the advantages of low melting temperature and good processability, and the sound-insulating layer is uniform in thickness during processing of the film and does not form insoluble substances with crystal points.
Detailed Description
The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.
Example 1
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0888PVA (0888 represents polymerization degree of 800 and alcoholysis degree of 88%) and 26.4kg of 2688PVA (2688 represents polymerization degree of 2600 and alcoholysis degree of 88%) were mixed and immersed in pure water for 30min, then heated to 90 ℃ to dissolve for 1.5h, and then kept warm for 2h after dissolving to prepare an 11% PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 18kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Example 2 use of 3 PVA blends
The method comprises the following steps:
(1) dissolving PVA: 2.4kg of 0888PVA, 3.6kg of 2088 PVA (2088 represents polymerization degree 2000 and alcoholysis degree 88%), and 24kg of 2688PVA were mixed with pure water, immersed for 30min, heated to 90 ℃ and dissolved for 1.5 hours, and then kept warm for 2 hours after dissolution to prepare a 11% PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 18kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 1 Using only one PVA
The method comprises the following steps:
(1) dissolving PVA: 30kg of 2688PVA is mixed with pure water and soaked for 30min, then the temperature is raised to 90 ℃, the PVA is dissolved for 1.5 hours, and the temperature is kept for 2 hours after the PVA is dissolved, so as to prepare 11 percent PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 18kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 2 use of PVA with high degree of alcoholysis
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0899PVA (0899 means 800 degree of polymerization and 99% of alcoholysis) and 26.4kg of 2699PVA (2699 means 2600 degree of polymerization and 99% of alcoholysis) were mixed with pure water and immersed for 30min, then heated to 90 ℃ to dissolve for 1.5h, and then kept warm for 2h to prepare an 11% PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature was lowered to 10 ℃, 20kg of n-butyraldehyde was added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 3 reduction of butyraldehyde and increase of hydroxyl group
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0888PVA and 26.4kg of 2688PVA are mixed with pure water and soaked for 30min, then the temperature is raised to 90 ℃, the mixture is dissolved for 1.5 hours, and the temperature is kept for 2 hours after the mixture is dissolved, so as to prepare 11 percent PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 15kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 4 changing the high temperature
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0888PVA and 26.4kg of 2688PVA are mixed with pure water and soaked for 30min, then the temperature is raised to 90 ℃, the mixture is dissolved for 1.5 hours, and the temperature is kept for 2 hours after the mixture is dissolved, so as to prepare 11 percent PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature was lowered to 10 ℃, 20kg of n-butyraldehyde was added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 50 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 50 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain finished PVB resin
Comparative example 5 changing the cryogenic temperature
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0888PVA and 26.4kg of 2688PVA are mixed with pure water and soaked for 30min, then the temperature is raised to 90 ℃, the mixture is dissolved for 1.5 hours, and the temperature is kept for 2 hours after the mixture is dissolved, so as to prepare 11 percent PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 15 deg.C, 20kg of n-butyraldehyde was added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 6
The method comprises the following steps:
(1) dissolving PVA: 10kg of 0888PVA (0888 represents polymerization degree 800 and alcoholysis degree 88%) and 20kg of 2688PVA (2688 represents polymerization degree 2600 and alcoholysis degree 88%) were mixed in pure water, immersed for 30min, heated to 90 ℃ and dissolved for 1.5 hours, and then kept warm for 2 hours after dissolution to prepare an 11% PVA solution.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 18kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Comparative example 7
The method comprises the following steps:
(1) dissolving PVA: 3.6kg of 0488PVA (0488 represents the polymerization degree of 400 and the alcoholysis degree of 88%) and 26.4kg of 2788PVA (2788 represents the polymerization degree of 2700 and the alcoholysis degree of 88%) are mixed and soaked in pure water for 30min, then the temperature is raised to 90 ℃, the mixture is dissolved for 1.5 hours, and the temperature is kept for 2 hours after the mixture is dissolved, so that a 11% PVA solution is prepared.
(2) Cooling, adding sodium dodecyl sulfate and hydrochloric acid: when the PVA solution system was cooled to 12 ℃ 0.18kg of sodium dodecylsulfate and 4kg of 30% hydrochloric acid were added.
(3) Adding n-butyraldehyde: when the temperature had dropped to 10 ℃ 18kg of n-butyraldehyde were added over 6 minutes.
(4) Low-temperature heat preservation: after n-butyraldehyde is added for reaction, phase change is carried out, and heat preservation is carried out for 1 hour.
(5) Starting temperature rise: after the low-temperature heat preservation is carried out for 1 hour, the temperature starts to rise, and the temperature rises to 68 ℃ within 2.5 hours.
(6) High-temperature heat preservation: incubate at 68 ℃ for 2 hours.
(7) Sodium hydroxide solution neutralization: and (3) after preserving heat at high temperature for 2 hours, adding a sodium hydroxide solution, adjusting the pH value to 4, preserving heat for 0.5 hour, and reacting to obtain a PVB crude product.
(8) Washing with water: the PVB crude product is washed by pure water to be neutral, the PH value is adjusted to 11 by adding sodium hydroxide solution, and the PVB crude product is washed by water after being stabilized for 1 hour until the PH value is 8.
(9) Centrifugally drying and drying to obtain the finished product PVB resin.
Test example
The PVB resin prepared above was subjected to the following performance tests:
(1) viscosity measurement
A detection instrument: VT-04 rotary viscometer
A20 g sample was weighed, dissolved in a 50 ℃ water bath using 180g absolute ethanol, and after complete dissolution, the resin viscosity was measured at 23 ℃ using a rotational viscometer.
(2) Detection of hydroxyl content
Acetic anhydride reacts with hydroxyl groups to obtain acetic acid, and the mass percent of the hydroxyl groups of the polyvinyl acetal resin is determined by an acetoxylation method.
Detection reagent pyridine (AR); acetic Anhydride (AR); 1, 2-dichloroethane (AR); phenolphthalein indicator; sodium hydroxide standard solution (0.5 mol/L).
Detecting an electronic balance of the instrument: the induction is 0.1 mg; grinding the conical flask: 250 mL; an alkali burette: 50 mL; a spherical condenser pipe: 300 mm; a water bath kettle; a pipette: 10mL and 5 mL; a measuring cylinder: 25 mL.
Analytical procedure
1. A sample of polyvinyl acetal (1 g; 0.1 mg; accurate) was weighed out accurately and placed in a 250mL ground flask.
2. A mixture of 90mL pyridine and 10mL acetic anhydride was prepared in a fume hood.
3. To a sample of polyvinyl acetal was added exactly 10mL of the mixture of step 2.
4. The conical bottle was loaded on a condenser tube and heated to 95. + -. 2 ℃ under reflux for 3 hours until the sample was completely dissolved.
5. The mixture of step 4 was cooled to room temperature and then 25mL of 1, 2-dichloroethane was added from the top of the condenser.
6. The condenser tube was removed, the stopper was closed and shaken gently.
7.5 mL of distilled water was added to wash the stopper and the wall of the flask, the mixture was shaken gently and left for 1 hour.
8. Remove 25mL of distilled water with a pipette and rinse along the wall of the flask.
9. Add phenolphthalein indicator 2 mL.
10. Titration was performed with 0.5mol/L sodium hydroxide standard solution.
Presentation of analysis results
1. The reaction product acetic acid was detected using 0.5mol/L NaOH standard solution, and Vs represents the volume of NaOH solution used for neutralizing acetic acid, and the mass of the neutralized polyvinyl acetal sample was E.
2. Let Vb denote the volume of the blank consuming the NaOH standard solution, i.e.the volume of acetic anhydride completely converted to acetic acid in the blank, 1mol of acetic acid corresponding to 1mol of polyvinyl alcohol (44 g).
3. The hydroxyl group content was calculated as follows
In the formula: x-hydroxy content,%;
Vb-titration of the blank consumes mL of the sodium hydroxide standard solution volume;
Vs-titration of sample consumption of sodium hydroxide standard solution volume, mL;
c-actual concentration of sodium hydroxide standard solution, mol/L;
sample mass of E-polyvinylacetal, g;
h-sample volatile content,%.
Two parallel tests are needed, the arithmetic mean value is taken as the test result, and the effective numerical value is regulated to two decimal points according to the GB/T8170.
Tolerance error: the difference between the two values of the parallel test results is not more than 0.3%.
The volatile content of the H sample is detected as follows:
the instrument comprises the following steps: an electronic balance: the induction is 0.1 mg; moisture content tester: the temperature control precision is +/-1 DEG C
The method comprises the following steps: before the moisture meter is used, the power supply is switched on. The temperature was set at 90 ℃ and the detection time was 5 minutes. The tray for placing the powder is placed in the apparatus and returned to zero. Putting a layer of tin-platinum paper on a tray, weighing 5-8 g (plus or minus 0.1g) of a sample, putting the sample in the tray, and pressing a start/stop key to start detection. After the detection is finished, the instrument can make an alarm sound, and the data is read by pressing a start/stop key. Reading the data to obtain the volatile matter of the sample to be measured. Two parallel tests should be performed, and the arithmetic mean value is taken as the test result.
(3) Detection of butyraldehyde group content
The content of butyraldehyde groups in the PVB resin is determined by titrating and quantifying a solution obtained after full reaction of a PVB absolute ethyl alcohol solution and a hydroxylamine hydrochloride standard solution by using a sodium hydroxide standard solution.
(4) Detection of melt index
Respectively taking 1.250g of 3GO and 3.750g of PVB resin, uniformly stirring, quickly adding the mixture into a melt flow rate meter at 118 ℃, adding a plunger, a guide sleeve and a basic weight, forcibly pressing and adding a weight of 21.6 kg. And after the instrument continuously discharges materials for three times, taking the materials and weighing, wherein the obtained weight is the melt index.
(5) Precipitation of plasticizer
The purpose of the test is as follows: the compatibility of the plasticizer with the resin was examined.
The test device comprises: electronic analytical balance, sulfuric acid dryer, tablet press.
Weighing 5g of PVB resin and 3g of 3GO plasticizer, uniformly stirring, and pressing into a test sample by using a tablet press; placing the prepared samples in a drier filled with sulfuric acid in sequence, taking out the samples after 5 days, and weighing the samples in sequence to obtain the mass m1. Placing the dried (called) sample in a desiccator filled with water in sequence, standing for 7 days, sucking the water on the surface of the sample with filter paper, drying in a sulfuric acid desiccator for 5 days, taking out, and sequentially weighing the sample with mass m2. (m) precipitation amount of plasticizer1-m2)/m1。
(6) Yield after sieving with a 40-mesh sieve
The yield of PVB resin passing through a 40 mesh sieve was calculated by weighing 100g of resin powder and the specific gravity of the weight after passing through a 40 mesh sieve to the total weight.
(7) High temperature resistance
Weigh 5g of PVB resin powder, place on a 15cm by 15cm glass slide, flatten the resin powder into a 10cm by 10cm circle, place in an oven at 180 ℃ and bake for 30 minutes, take out and observe the resin appearance.
Specific detection results are shown in table 1:
TABLE 1
As shown in Table 1, the PVB resin prepared by mixing the PVAs with different polymerization degrees has high melt index and better processability. As can be seen from comparative example 3, too high a hydroxyl content can affect the compatibility of PVB with 3GO plasticizers and can also reduce the melt index of the PVB resin. As can be seen from comparative examples 6 and 7, the content or degree of polymerization of PVA with a small molecular weight in the PVB resin cannot be too high, and too high can cause the temperature resistance of the PVB to be reduced, thereby causing severe yellowing due to decomposition at high temperature.
The above detailed description is specific to one possible embodiment of the present invention, and the embodiment is not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention should be included in the technical scope of the present invention.