A method for preparing and using a polyvinyl butyral resin

Abstract

The application discloses a preparation method and application of polyvinyl butyral resin, and comprises the following steps: (1) dissolving polyvinyl alcohol in water to obtain PVA hydrogel; (2) adding the suspension into a feeding kettle, adjusting the pH value, and then adding the PVA hydrogel and n-butyl aldehyde within a period of time, and then mixing and stirring to obtain a mixed solution; (3) transferring the mixed solution into a reaction kettle, heating, and then reacting for a period of time to obtain a second mixed solution; the supernatant of the second mixed solution can be recycled as the suspension in step (2); (4) adding water and an antioxidant into the second mixed solution, heating, and then reacting for a period of time to obtain a third mixed solution; and (5) performing solid-liquid separation, washing and drying on the third mixed solution to obtain the polyvinyl butyral resin; the polyvinyl butyral resin prepared by the preparation method has low yellowing index, high yield, high butyl aldehyde utilization rate and high acetalization rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer material preparation, and the classification number is C08F16 / 06. Specifically, the present application relates to a preparation method and application of polyvinyl butyral resin. BACKGROUND

[0002] Polyvinyl butyral resin is a new type of polymer material generated by the chain condensation reaction of polyvinyl alcohol hydrogel and n-butyl aldehyde under the condition of an acidic catalyst. The PVB film made by mixing polyvinyl butyral resin, plasticizer and plastic additive in a certain proportion has high cold resistance, impact resistance and ultraviolet resistance, and can be used as a sandwich material of safety glass. The prepared safety glass has good transparency, high impact strength and high safety, and is widely used in the fields of aviation, automobile and building.

[0003] In the initial stage of PVB double-strand feeding, due to the presence of a certain amount of acidic bottom liquid in the feeding kettle system, PVA hydrogel and n-butyl aldehyde are fed in opposite directions, and under the condition of high-speed stirring, PVA and butyl aldehyde are quickly dispersed in the solution system, and the reaction of PVA and butyl aldehyde slowly proceeds in the homogeneous phase. When the feeding process proceeds to a certain degree, the number of acetal groups converted from the hydroxyl groups on the PVA molecular chain is higher than the critical value, the polarity of the generated PVB particles is reduced, and a small part of the free nascent PVB particles will accumulate along the reaction kettle wall and stirring paddle under the influence of high-speed stirring, and the resin climbing phenomenon occurs, which eventually leads to low product yield, low butyl aldehyde utilization rate, and further leads to unstable product quality. Most of the nascent PVB particles uniformly dispersed in the reaction system are affected by the specific surface area of the resin particles, and the PVA molecules and butyl aldehyde acetalization reaction is intense in the early stage of the reaction, the immature PVA macromolecular chain is quickly wrapped by the newly added PVA molecules, which leads to the fact that butyl aldehyde cannot enter the inside of the PVB particles to acetalize with the hydroxyl groups, but can only be on the surface of the solid particles, resulting in low acetalization rate of the finished PVB particles and low butyl aldehyde utilization rate.

[0004] Chinese patent CN111690083A discloses a preparation method of polyvinyl butyral resin, which mainly replaces the reaction nascent PVB particles by using finished high-acetalization PVB nascent particles, so as to solve the problems of low acetalization rate and uneven distribution of acetal groups in the finished PVB particles. However, due to the limitation of the synthesis reaction process, in order to uniformly disperse the finished high-acetalization PVB particles into the reaction system, the use amount of the finished high-acetalization PVB particles is reduced, and the particle size of the high-acetalization PVB particles is increased. Although the acetalization rate of the PVB particles and the butyl aldehyde utilization rate can be improved to a certain extent, the improvement degree is low, and the phenomenon of resin clumping and uneven dispersion is easy to occur during preparation.

[0005] Chinese patent CN116041570A discloses a preparation method of polyvinyl butyral resin, mainly through the surface active agent sodium carboxymethyl cellulose, so that the polyvinyl alcohol, catalyst and n-butyl aldehyde in the system are uniformly mixed and well dispersed, without crosslinking and caking phenomenon, thereby improving the acetal degree of the product, but the removal of the surfactant is difficult, a large amount of water needs to be consumed, resulting in cost increase, and incomplete removal of the surfactant will cause the adhesive force between the PVB interlayer and the glass surface to be greatly reduced, limiting the application of the prepared PVB film in the fields of automobiles, buildings and photovoltaics. SUMMARY

[0006] To solve the above problems, the first aspect of the present application provides a preparation method of polyvinyl butyral resin, which comprises the following steps:

[0007] (1) Dissolve polyvinyl alcohol in water above 90℃, stir and dissolve it in a dissolving kettle, then filter and cool it to 40-50℃ to obtain PVA hydrogel.

[0008] (2) Mix polyvinyl butyral resin particles, acid catalyst, water, n-butyl aldehyde and 2-ethylhexenal by weight parts to obtain a suspension, add it to a feeding kettle, then add inorganic acid to adjust the pH value to 1-2, maintain the temperature at 40-50℃, add PVA hydrogel and n-butyl aldehyde within 15-25min, and mix and stir to obtain a mixed solution;

[0009] (3) Transfer the mixed solution to a reaction kettle, heat it to 60-70℃, react for 2-4h to obtain a second mixed solution; extract the supernatant of the second mixed solution as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0010] (4) Add water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, then add in antioxidant, heat it to 70-90℃, react for 0.5-1.5h to obtain a third mixed solution;

[0011] (5) After solid-liquid separation, washing and drying, polyvinyl butyral resin is obtained.

[0012] Preferably, the raw materials for preparing the polyvinyl butyral resin include, by weight parts, 200-600 parts of suspension, 200-400 parts of polyvinyl alcohol, 150-250 parts of n-butyl aldehyde, 3-15 parts of inorganic acid, 1-5 parts of antioxidant and 2000-4500 parts of water.

[0013] Further preferably, the raw materials for preparing the polyvinyl butyral resin comprise, by weight, 240-600 parts of a suspension, 300-400 parts of polyvinyl alcohol, 180-240 parts of n-butyraldehyde, 3-10 parts of an inorganic acid, 1-3 parts of an antioxidant, and 2400-3200 parts of water.

[0014] Further preferably, the raw materials for preparing the polyvinyl butyral resin comprise, by weight, 420 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyraldehyde, 5 parts of an inorganic acid, 2 parts of an antioxidant, and 2800 parts of water.

[0015] Further preferably, the antioxidant is antioxidant 1076 and / or antioxidant 1010.

[0016] Preferably, the inorganic acid is at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0017] Further preferably, the inorganic acid is hydrochloric acid.

[0018] Preferably, the mass fraction of the inorganic acid is 10-40%.

[0019] Further preferably, the mass fraction of the inorganic acid is 20-40%.

[0020] Further preferably, the mass fraction of the inorganic acid is 10-37%.

[0021] Further preferably, the mass fraction of the inorganic acid is 37%.

[0022] Preferably, the polyvinyl alcohol has a degree of polymerization of 1000-2000 and an alcoholysis degree of 85-99%.

[0023] Further preferably, the polyvinyl alcohol comprises at least one of PVA1799, PVA1797, PVA1795, PVA1788, PVA1999, PVA2099, PVA2488, PVA2699, and PVA1899.

[0024] Further preferably, the polyvinyl alcohol is PVA1799 and / or PVA1899.

[0025] Further preferably, the polyvinyl alcohol is PVA1899, has a degree of polymerization of 1800, and an alcoholysis degree of 99%.

[0026] Preferably, the raw materials for preparing the suspension in step (2) comprise, by weight, 1-5 parts of polyvinyl butyral resin microparticles, 1-5 parts of an acidic catalyst, and 50-200 parts of water.

[0027] Further preferably, the raw materials for preparing the suspension in step (2) include, by weight, 1-3 parts of polyvinyl butyral resin microparticles, 2-4 parts of an acidic catalyst, and 100-200 parts of water.

[0028] Further preferably, the raw materials for preparing the suspension in step (2) include, by weight, 1 part of polyvinyl butyral resin microparticles, 3 parts of an acidic catalyst, and 150 parts of water.

[0029] Preferably, the raw materials for preparing the suspension in step (2) further include 0.1-0.5 parts of n-butyraldehyde and 0.01-0.05 parts of 2-ethylhexenal.

[0030] Further preferably, the raw materials for preparing the suspension in step (2) further include 0.2-0.4 parts of n-butyraldehyde and 0.02-0.04 parts of 2-ethylhexenal.

[0031] Further preferably, the raw materials for preparing the suspension in step (2) further include 0.3 parts of n-butyraldehyde and 0.03 parts of 2-ethylhexenal.

[0032] Preferably, the polyvinyl butyral resin microparticles have an average particle size of 5-30 μm.

[0033] Further preferably, the polyvinyl butyral resin microparticles have an average particle size of 10-20 μm.

[0034] Further preferably, the polyvinyl butyral resin microparticles have an average particle size of 15 μm.

[0035] Preferably, the polyvinyl butyral resin microparticles have an acetalization rate of no less than 60%.

[0036] Further preferably, the polyvinyl butyral resin microparticles have an acetalization rate of 70-90%.

[0037] Further preferably, the polyvinyl butyral resin microparticles have an acetalization rate of 80%.

[0038] The second aspect of the present application provides an application of the method for preparing polyvinyl butyral resin in the preparation of building safety glass, automobile front windshield glass, and solar cell panel interlayer film.

[0039] The prior art method for preparing polyvinyl butyral resin has the technical problems of low acetalization rate of PVB particles and low utilization rate of butyraldehyde, in order to solve the problems, the inventors add a suspension liquid in the preparation process, and limit the amount of polyvinyl butyral resin particles in the suspension liquid to 1-3 parts, under the joint action of 10-37% hydrochloric acid, not only the high acidity of hydrochloric acid can avoid the situation that the local acetalization reaction is too fast, and the agglomeration and uneven acetalization distribution occur, but also the acetalization rate of PVB particles and the utilization rate of butyraldehyde can be greatly improved, because the average particle size of the high-acetalization polyvinyl butyral resin particles in the suspension liquid is 10-20 μm, the crystal nucleus in the system is small, and the dispersion is more uniform, and the suspension liquid contains a small amount of n-butyraldehyde and 2-ethylhexenal, which can make the steric hindrance of the solid particles separated from the tank larger, there is a certain gap between the particles, and the agglomeration degree is low, and the technical problems of the phenomenon that the resin clumps and is not uniformly dispersed after directly adding high-acetalization polyvinyl butyral particles in the prior art are solved, the resin acetalization is uniform, the intermolecular crosslinking reaction is not easy to occur, the utilization rate of butyraldehyde is as high as 97.3%, the acetalization rate is as high as 83.0%, the thermal stability and yellowing resistance of the resin are improved, and the yellow index is reduced to 1.6, on this basis, the weight of the suspension liquid is further limited to 240-600 parts, and the technical problem that the weight of the suspension liquid is too large and the utilization rate of butyraldehyde is reduced is avoided.

[0040] Advantages:

[0041] (1) In the present application, the suspension liquid prepared in advance and uniformly dispersed is added to the system, which avoids the phenomenon that the resin clumps and is not uniformly dispersed after adding polyvinyl butyral particles in the prior art, and further ensures that butyraldehyde can react with the hydroxyl group in polyvinyl without entering the inside of the product, which can significantly improve the distribution of acetal groups in the finished PVB resin particles, increase the utilization rate of butyraldehyde, and improve the thermal stability of the resin.

[0042] (2) In the present application, by limiting the average particle size and amount of polyvinyl butyral particles in the suspension liquid, under the joint action of 10-37% hydrochloric acid, the high acidity of hydrochloric acid can avoid the situation that the local acetalization reaction is too fast, and the agglomeration and uneven acetalization distribution occur, and the suspension liquid contains a small amount of n-butyraldehyde and 2-ethylhexenal, which can make the utilization rate of butyraldehyde in the prepared PVB resin as high as 97.3%, the acetalization rate as high as 83.0%, improve the thermal stability and yellowing resistance of the resin, and reduce the yellow index to 1.6.

[0043] (3) The method for preparing polyvinyl butyral resin in the present application avoids the phenomenon of resin climbing during stirring, which reduces the product yield and affects the yellowing index.

[0044] (4) The method for preparing the polyvinyl butyral resin does not need to add a surfactant and an emulsifier, and cannot cause the problem of incomplete removal of the surfactant, which can greatly reduce the adhesion between the PVB interlayer film and the glass surface, and the prepared PVB resin is more suitable for the fields of building safety glass, automobile front windshield glass and solar cell panel interlayer film and the like.

[0045] (5) In the method for preparing the polyvinyl butyral resin, the supernatant of the second mixed solution is recycled as the suspension in step (2) in step (3), which can reduce the wastewater generated by the system, is friendly to the environment, has good stability of the PVB resin, and solves the problem in the prior art that the preparation process of the PVB resin needs to additionally add PVB crystal nucleus microparticles to improve the acetalization rate of the PVB resin and the butyraldehyde utilization rate, but can cause poor stability of the PVB resin. EMBODIMENT

[0046] Example 1

[0047] A method for preparing a polyvinyl butyral resin, which comprises the following steps:

[0048] (1) Dissolve polyvinyl alcohol in water at 95℃, wherein the solid content of the polyvinyl alcohol solution is 10%, and after stirring and dissolving in a dissolving kettle, filter and cool to 45℃ to obtain a PVA hydrogel;

[0049] (2) Mix polyvinyl butyral resin microparticles, an acidic catalyst, water, n-butyl aldehyde and 2-ethylhexenal by weight parts to obtain a suspension, add the suspension to a feeding kettle, add an inorganic acid to adjust the pH value to 1.5, maintain the temperature at 45℃, add the PVA hydrogel and n-butyl aldehyde within 20 min, and after mixing and stirring, obtain a mixed solution;

[0050] (3) Transfer the mixed solution to a reaction kettle, heat to 65℃, and react for 3h to obtain a second mixed solution; extract the supernatant of the second mixed solution as the suspension in step (2) for recycling, wherein the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0051] (4) Add water to the second mixed solution, wherein the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, then add an antioxidant, heat to 80℃, and react for 1h to obtain a third mixed solution;

[0052] (5) After the third mixed solution is subjected to solid-liquid separation, washing and drying, a polyvinyl butyral resin is obtained.

[0053] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 240 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of an inorganic acid, 2 parts of an antioxidant and 2800 parts of water.

[0054] The raw materials for preparing the suspension include, by weight parts, polyvinyl butyral resin microparticles 1 part, acidic catalyst 3 parts, water 150 parts, n-butyraldehyde 0.3 part, and 2-ethylhexenal 0.03 part.

[0055] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0056] The polyvinyl butyral resin microparticles have an average particle size of 15 μm and an acetalization rate of 80%, and are available from HUBI YIMIN PLASTIC TECHNOLOGY CO., LTD. with a model number of 20D.

[0057] The acidic catalyst is hydrochloric acid with a mass fraction of 37%.

[0058] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0059] The antioxidant is antioxidant 1010.

[0060] The second aspect of the embodiment provides an application of the preparation method of the polyvinyl butyral resin in the preparation of building safety glass, automobile front windshield glass, and solar cell panel interlayer film.

[0061] Example 2

[0062] A preparation method of polyvinyl butyral resin, which comprises the following steps:

[0063] (1) dissolving polyvinyl alcohol in water at 95℃, wherein the solid content of the polyvinyl alcohol solution is 10%, and after stirring and dissolving in a dissolving kettle, the solution is filtered and cooled to 45℃ to obtain a PVA hydrogel;

[0064] (2) mixing, by weight parts, polyvinyl butyral resin microparticles, an acidic catalyst, water, n-butyraldehyde, and 2-ethylhexenal to obtain a suspension, adding the suspension into a feeding kettle, adding an inorganic acid to adjust the pH value to 1.5, maintaining the temperature at 45℃, adding the PVA hydrogel and n-butyraldehyde within 20 min, and mixing and stirring to obtain a mixed solution;

[0065] (3) transferring the mixed solution to a reaction kettle, heating to 65℃, and reacting for 3 h to obtain a second mixed solution; extracting the supernatant of the second mixed solution as the suspension in step (2) for recycling, wherein the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0066] (4) adding water to the second mixed solution, wherein the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, then adding an antioxidant, heating to 80℃, and reacting for 1 h to obtain a third mixed solution;

[0067] (5) the third mixed solution is subjected to solid-liquid separation, washing and drying to obtain the polyvinyl butyral resin.

[0068] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 300 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of butyraldehyde, 5 parts of inorganic acid, 2 parts of antioxidant and 2800 parts of water.

[0069] The raw materials for preparing the suspension include, by weight parts, 1 part of polyvinyl butyral resin microparticles, 3 parts of acidic catalyst, 150 parts of water, 0.3 parts of n-butyraldehyde and 0.03 parts of 2-ethylhexenal.

[0070] The polyvinyl alcohol is PVA1899, the degree of polymerization is 1800 and the alcoholysis degree is 99%.

[0071] The polyvinyl butyral resin microparticles have an average particle size of 15 μm and an acetalization rate of 80%, are purchased from Huxibei Yimin Plastic Technology Co., Ltd. and have a model number of 20D.

[0072] The acidic catalyst is hydrochloric acid with a mass fraction of 37%.

[0073] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0074] The antioxidant is antioxidant 1010.

[0075] The second aspect of the embodiment provides an application of the preparation method of the polyvinyl butyral resin in the preparation of building safety glass, automobile front windshield glass and solar cell panel interlayer film.

[0076] Example 3

[0077] A preparation method of a polyvinyl butyral resin, which comprises the following steps:

[0078] (1) polyvinyl alcohol is dissolved in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after being stirred and dissolved by a dissolving kettle, the solution is filtered and cooled to 45℃ to obtain a PVA hydrogel;

[0079] (2) polyvinyl butyral resin microparticles, acidic catalyst, water, n-butyraldehyde and 2-ethylhexenal are mixed to obtain a suspension, which is added into a feeding kettle, inorganic acid is added to adjust the pH value to 1.5, the temperature is maintained at 45℃, the PVA hydrogel and n-butyraldehyde are added within 20 min, and a mixed solution is obtained after mixing and stirring;

[0080] (3) transferring the mixed solution to a reactor, warming to 65℃, and reacting for 3h to obtain a second mixed solution; the supernatant of the second mixed solution is extracted and used as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0081] (4) adding water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, warming to 80℃, and reacting for 1h to obtain a third mixed solution;

[0082] (5) obtaining the polyvinyl butyral resin through solid-liquid separation, washing, and drying of the third mixed solution.

[0083] The preparation raw material of the polyvinyl butyral resin includes, by weight parts, 360 parts of the suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyraldehyde, 5 parts of inorganic acid, 2 parts of antioxidant, and 2800 parts of water.

[0084] The rest is the same as in Example 1.

[0085] Example 4

[0086] A preparation method of a polyvinyl butyral resin, the method comprising the following steps:

[0087] (1) dissolving polyvinyl alcohol in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after stirring and dissolving through a dissolving kettle, filtering, and then cooling to 45℃, a PVA hydrogel is obtained;

[0088] (2) mixing, by weight parts, polyvinyl butyral resin particles, an acidic catalyst, water, n-butyraldehyde, and 2-ethylhexene aldehyde to obtain a suspension, adding the suspension to a feeding kettle, adding inorganic acid to adjust the pH value to 1.5, maintaining the temperature at 45℃, adding the PVA hydrogel and n-butyraldehyde within 20min, and mixing and stirring to obtain a mixed solution;

[0089] (3) transferring the mixed solution to a reactor, warming to 65℃, and reacting for 3h to obtain a second mixed solution; the supernatant of the second mixed solution is extracted and used as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0090] (4) adding water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, warming to 80℃, and reacting for 1h to obtain a third mixed solution;

[0091] (5) obtaining the polyvinyl butyral resin through solid-liquid separation, washing, and drying of the third mixed solution.

[0092] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 420 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of antioxidant, and 2800 parts of water.

[0093] The rest is the same as in Example 1.

[0094] Example 5

[0095] A method for preparing a polyvinyl butyral resin, the method comprising the following steps:

[0096] (1) Dissolve polyvinyl alcohol in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after stirring and dissolving in a dissolving kettle, filter and cool to 45℃ to obtain a PVA hydrogel;

[0097] (2) Mix, by weight parts, polyvinyl butyral resin particles, acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenal to obtain a suspension, add the suspension to a feeding kettle, add inorganic acid to adjust the pH value to 1.5, maintain the temperature at 45℃, add the PVA hydrogel and n-butyl aldehyde within 20 min, and after mixing and stirring, obtain a mixed solution;

[0098] (3) Transfer the mixed solution to a reaction kettle, heat to 65℃, and react for 3h to obtain a second mixed solution; extract the supernatant of the second mixed solution as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0099] (4) Add water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, then add antioxidant, heat to 80℃, and react for 1h to obtain a third mixed solution;

[0100] (5) After the third mixed solution is subjected to solid-liquid separation, washing, and drying, a polyvinyl butyral resin is obtained.

[0101] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 480 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of antioxidant, and 2800 parts of water.

[0102] The rest is the same as in Example 1.

[0103] Example 6

[0104] A method for preparing a polyvinyl butyral resin, the method comprising the following steps:

[0105] (1) polyvinyl alcohol is dissolved in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after stirring and dissolving in a dissolving kettle, filtering and cooling to 45℃, a PVA hydrogel is obtained;

[0106] (2) polyvinyl butyral resin microparticles, an acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenal are mixed according to weight parts to obtain a suspension, which is added to a feeding kettle, inorganic acid is added to adjust the pH value to 1.5, the temperature is maintained at 45℃, the PVA hydrogel and n-butyl aldehyde are added within 20 min, and after mixing and stirring, a mixed solution is obtained;

[0107] (3) the mixed solution is transferred to a reaction kettle, heated to 65℃, and reacted for 3h to obtain a second mixed solution; the supernatant of the second mixed solution is extracted as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0108] (4) water is added to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, then an antioxidant is added, heated to 80℃, and reacted for 1h to obtain a third mixed solution;

[0109] (5) the third mixed solution is subjected to solid-liquid separation, washing, and drying to obtain polyvinyl butyral resin.

[0110] The preparation raw materials of the polyvinyl butyral resin include, by weight parts, 540 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of an antioxidant, and 2800 parts of water.

[0111] The rest is the same as in Example 1.

[0112] Example 7

[0113] A method for preparing polyvinyl butyral resin, the method comprising the following steps:

[0114] (1) polyvinyl alcohol is dissolved in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after stirring and dissolving in a dissolving kettle, filtering and cooling to 45℃, a PVA hydrogel is obtained;

[0115] (2) polyvinyl butyral resin microparticles, an acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenal are mixed according to weight parts to obtain a suspension, which is added to a feeding kettle, inorganic acid is added to adjust the pH value to 1.5, the temperature is maintained at 45℃, the PVA hydrogel and n-butyl aldehyde are added within 20 min, and after mixing and stirring, a mixed solution is obtained;

[0116] (3) transferring the mixed solution to a reactor, warming to 65℃, and reacting for 3h to obtain a second mixed solution; the supernatant of the second mixed solution is extracted and used as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0117] (4) adding water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, warming to 80℃, and reacting for 1h to obtain a third mixed solution;

[0118] (5) obtaining the polyvinyl butyral resin through solid-liquid separation, washing, and drying of the third mixed solution.

[0119] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 600 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyraldehyde, 5 parts of an inorganic acid, 2 parts of an antioxidant, and 2800 parts of water.

[0120] The rest is the same as in Example 1.

[0121] Comparative Example 1

[0122] A method for preparing a polyvinyl butyral resin, the method comprising the following steps:

[0123] (1) dissolving polyvinyl alcohol in water at 95℃, at this time the solid content of the polyvinyl alcohol solution is 10%, after stirring and dissolving through a dissolving kettle, filtering, and then cooling to 45℃, a PVA hydrogel is obtained;

[0124] (2) mixing, by weight parts, polyvinyl butyral resin particles, an acidic catalyst, and water to obtain a suspension, adding the suspension to a feeding kettle, adding an inorganic acid to adjust the pH value to 1.5, maintaining the temperature at 45℃, adding the PVA hydrogel and n-butyraldehyde within 20min, and after mixing and stirring, a mixed solution is obtained;

[0125] (3) transferring the mixed solution to a reactor, warming to 65℃, and reacting for 3h to obtain a second mixed solution; the supernatant of the second mixed solution is extracted and used as the suspension in step (2) for recycling, at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0126] (4) adding water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, warming to 80℃, and reacting for 1h to obtain a third mixed solution;

[0127] (5) obtaining the polyvinyl butyral resin through solid-liquid separation, washing, and drying of the third mixed solution.

[0128] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, a suspension 420, polyvinyl alcohol 360, n-butyl aldehyde 210, inorganic acid 5, antioxidant 2, and water 2800.

[0129] The raw materials for preparing the suspension include, by weight parts, polyvinyl butyral resin microparticles 1, acidic catalyst 3, and water 150.

[0130] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0131] The polyvinyl butyral resin microparticles have an average particle size of 15 μm and an acetalization rate of 80%, and are available from Huluk Yimin Plastic Co., Ltd. with a model number of 20D.

[0132] The rest is the same as in Example 4.

[0133] Comparative Example 2

[0134] A method for preparing a polyvinyl butyral resin, the method comprising the following steps:

[0135] (1) Dissolve polyvinyl alcohol in water at 95℃, with a solid content of the polyvinyl alcohol solution being 10%, and then filter and cool to 45℃ to obtain a PVA hydrogel;

[0136] (2) Mix polyvinyl butyral resin microparticles, acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenal by weight parts to obtain a suspension, add the suspension to a feeding kettle, add inorganic acid to adjust the pH value to 1.5, maintain the temperature at 45℃, add the PVA hydrogel and n-butyl aldehyde within 20 min, and then mix and stir to obtain a mixed solution;

[0137] (3) Transfer the mixed solution to a reaction kettle, heat to 65℃, and react for 3 h to obtain a second mixed solution; extract the supernatant of the second mixed solution as the suspension in step (2) for recycling, and at this time the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0138] (4) Add water to the second mixed solution, at this time the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then add in an antioxidant, heat to 80℃, and react for 1 h to obtain a third mixed solution;

[0139] (5) Subject the third mixed solution to solid-liquid separation, washing, and drying to obtain the polyvinyl butyral resin.

[0140] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, polyvinyl butyral resin particles 1 part, a suspension 420 parts, polyvinyl alcohol 360 parts, n-butyl aldehyde 210 parts, inorganic acid 5 parts, antioxidant 2 parts, and water 2800 parts.

[0141] The raw materials for preparing the suspension include, by weight parts, polyvinyl butyral resin particles 1 part, acid catalyst 3 parts, and water 150 parts.

[0142] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0143] The polyvinyl butyral resin particles have an average particle size of 15 μm and an acetalization rate of 80%, and are available from HUBI YIMIN PLASTIC TECHNOLOGY CO., LTD. with a model number of 20D.

[0144] The acid catalyst is hydrochloric acid with a mass fraction of 37%.

[0145] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0146] The antioxidant is antioxidant 1010.

[0147] The rest is the same as in Example 4.

[0148] Comparative Example 3

[0149] The present comparative example sets a method for preparing polyvinyl butyral resin in the prior art.

[0150] A method for preparing polyvinyl butyral resin, which includes three main procedures of dissolving, condensation, and post-treatment, and specifically as follows:

[0151] The dissolving procedure: polyvinyl alcohol is completely dissolved and uniformly mixed in hot water at 95℃ by stirring to form a polyvinyl alcohol aqueous solution; the polyvinyl alcohol aqueous solution is filtered and cooled to 70℃, polyvinyl butyral is added, and the raw material polyvinyl butyral is uniformly dispersed in the polyvinyl alcohol aqueous solution by sufficient stirring to form a mixed solution; the temperature is continuously lowered to 50℃, n-butyl aldehyde is added, and the n-butyl aldehyde is uniformly dispersed in the above mixed solution by sufficient stirring to form a reaction liquid.

[0152] The condensation procedure: the reaction liquid is cooled to 8℃, inorganic acid is added dropwise, and incubated for 1 h; then the temperature of the reaction system is raised to 25℃ within 1 h, and incubated for 1.5 h; then the temperature of the reaction system is raised to 45℃ within 1 h, and incubated for 1.5 h; then the temperature of the reaction system is raised to 70℃ within 1.5 h, and incubated for 2 h; after the reaction is completed, a reaction mother liquor containing granular PVB semi-finished product is formed.

[0153] The reaction mother liquor containing the granular PVB semi-finished product is subjected to solid-liquid separation to obtain a PVB semi-finished product, which is washed with deionized water and dried to obtain the polyvinyl butyral resin.

[0154] The polyvinyl butyral resin is prepared from 1 part of polyvinyl butyral, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of antioxidant and 2800 parts of water.

[0155] The polyvinyl alcohol is PVA1899 with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0156] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0157] The antioxidant is antioxidant 1010.

[0158] The polyvinyl butyral has an average particle size of 15 μm and an acetalization rate of 80%.

[0159] Comparative Example 4

[0160] A method for preparing a polyvinyl butyral resin, which comprises the following steps:

[0161] (1) dissolving polyvinyl alcohol in water at 95℃, wherein the solid content of the polyvinyl alcohol solution is 10%, and then filtering and cooling to 45℃ to obtain a PVA hydrogel;

[0162] (2) mixing polyvinyl butyral resin particles, an acidic catalyst, water, n-butyl aldehyde and 2-ethylhexenal by weight parts to obtain a suspension, adding the suspension into a feeding kettle, adding inorganic acid to adjust the pH value to 1.5, maintaining the temperature at 45℃, adding the PVA hydrogel and n-butyl aldehyde within 20 min, and mixing and stirring to obtain a mixed solution;

[0163] (3) transferring the mixed solution into a reaction kettle, heating to 65℃, and reacting for 3 h to obtain a second mixed solution; extracting the supernatant of the second mixed solution as the suspension in step (2) for recycling, wherein the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0164] (4) adding water into the second mixed solution, wherein the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, heating to 80℃, and reacting for 1 h to obtain a third mixed solution;

[0165] (5) subjecting the third mixed solution to solid-liquid separation, washing and drying to obtain the polyvinyl butyral resin.

[0166] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, a suspension 420 parts, polyvinyl alcohol 360 parts, n-butyl aldehyde 210 parts, inorganic acid 5 parts, antioxidant 2 parts, and water 2800 parts.

[0167] The raw materials for preparing the suspension include, by weight parts, polyvinyl butyral resin microparticles 1 part, acidic catalyst 3 parts, water 150 parts, n-butyl aldehyde 0.3 part, and 2-ethylhexenal 0.03 part.

[0168] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0169] The polyvinyl butyral resin microparticles have an average particle size of 20-200 mesh, an acetalization rate of 76-85%, and a model of 6S, which are purchased from Guangdong Yuemei Chemical Co., Ltd.

[0170] The rest is the same as in Example 4.

[0171] Comparative Example 5

[0172] A method for preparing a polyvinyl butyral resin, which comprises the following steps:

[0173] (1) Dissolve the polyvinyl alcohol in water at 95℃, wherein the solid content of the polyvinyl alcohol solution is 10%, and then filter and cool to 45℃ to obtain a PVA hydrogel;

[0174] (2) Mix, by weight parts, polyvinyl butyral resin microparticles, acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenal to obtain a suspension, add the suspension to a feeding kettle, add inorganic acid to adjust the pH value to 1.5, maintain the temperature at 45℃, add the PVA hydrogel and n-butyl aldehyde within 20 min, and then mix and stir to obtain a mixed solution;

[0175] (3) Transfer the mixed solution to a reaction kettle, heat to 65℃, and react for 3 h to obtain a second mixed solution; extract the supernatant of the second mixed solution as the suspension in step (2) for recycling, wherein the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0176] (4) Add water to the second mixed solution, wherein the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then add an antioxidant, heat to 80℃, and react for 1 h to obtain a third mixed solution;

[0177] (5) Subject the third mixed solution to solid-liquid separation, washing, and drying to obtain the polyvinyl butyral resin.

[0178] The raw materials for preparing the polyvinyl butyral resin include, by weight parts, 650 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of antioxidant, and 2800 parts of water.

[0179] The raw materials for preparing the suspension include, by weight parts, 1 part of polyvinyl butyral resin microparticles, 3 parts of acidic catalyst, 150 parts of water, 0.3 parts of n-butyl aldehyde, and 0.03 parts of 2-ethylhexenaldehyde.

[0180] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0181] The polyvinyl butyral resin microparticles have an average particle size of 15 μm and an acetalization rate of 80%, and are available from HUBI YIMIN PLASTIC TECHNOLOGY CO., LTD. with a model number of 20D.

[0182] The acidic catalyst is hydrochloric acid with a mass fraction of 37%.

[0183] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0184] The antioxidant is antioxidant 1010.

[0185] The rest is the same as in Example 4.

[0186] Comparative Example 6

[0187] A method for preparing a polyvinyl butyral resin, the method comprising the following steps:

[0188] (1) dissolving polyvinyl alcohol in water at 95℃, wherein the solid content of the polyvinyl alcohol solution is 10%, and after stirring and dissolving in a dissolving kettle, the solution is filtered and cooled to 45℃ to obtain a PVA hydrogel;

[0189] (2) mixing, by weight parts, polyvinyl butyral resin microparticles, acidic catalyst, water, n-butyl aldehyde, and 2-ethylhexenaldehyde to obtain a suspension, adding the suspension into a feeding kettle, adding inorganic acid to adjust the pH value to 1.5, maintaining the temperature at 45℃, adding the PVA hydrogel and n-butyl aldehyde within 20 min, and mixing and stirring to obtain a mixed solution;

[0190] (3) transferring the mixed solution into a reaction kettle, heating to 65℃, and reacting for 3 h to obtain a second mixed solution; extracting the supernatant of the second mixed solution as the suspension in step (2) for recycling, wherein the total volume of the supernatant accounts for 1 / 4 of the total volume of the second mixed solution;

[0191] (4) adding water into the second mixed solution, wherein the total volume of the water accounts for 1 / 4 of the total volume of the second mixed solution, and then adding an antioxidant, heating to 80℃, and reacting for 1 h to obtain a third mixed solution;

[0192] (5) The third mixed solution is subjected to solid-liquid separation, washing and drying to obtain the polyvinyl butyral resin.

[0193] The raw materials for preparing the polyvinyl butyral resin include, by weight, 420 parts of a suspension, 360 parts of polyvinyl alcohol, 210 parts of n-butyl aldehyde, 5 parts of inorganic acid, 2 parts of antioxidant and 2800 parts of water.

[0194] The raw materials for preparing the suspension include, by weight, 8 parts of polyvinyl butyral resin microparticles, 3 parts of acidic catalyst, 150 parts of water, 0.3 parts of n-butyl aldehyde and 0.03 parts of 2-ethylhexenal.

[0195] The polyvinyl alcohol is PVA1899, with a polymerization degree of 1800 and an alcoholysis degree of 99%.

[0196] The polyvinyl butyral resin microparticles have an average particle size of 15 μm and an acetalization rate of 80%, and are available from HUBI YIMIN PLASTIC TECHNOLOGY CO., LTD. and are of type 20D.

[0197] The acidic catalyst is hydrochloric acid with a mass fraction of 37%.

[0198] The inorganic acid is hydrochloric acid with a mass fraction of 37%.

[0199] The antioxidant is antioxidant 1010.

[0200] The rest is the same as in Example 4.

[0201] Performance Evaluation

[0202] 1. Test of the climbing height of PVB particles along the stirring paddle and the dispersion of the particles: the climbing height of PVB particles along the stirring paddle and the dispersion of the particles in the system are observed after the PVA hydrogel and n-butyl aldehyde are added in step (2) of the present application, and the system is mixed and stirred. If the dispersion is good and there is no agglomeration, the system is qualified, otherwise, the system is unqualified.

[0203] 2. Test of the acetalization degree: the acetalization degree is determined by allowing the butylal acetal groups on the PVB molecular chain to react with hydrochloric acid to generate PVA and HCl, then using australine blue or methyl orange as an indicator, titrating the generated HCl with a standard sodium hydroxide solution, and calculating the content (B) of the butylal acetal groups in the PVB according to the amount of the alkali, according to the following formula: In the formula, V1 is the volume of the sodium hydroxide standard solution consumed in the titration of the PVB sample (unit: milliliter); V2 is the volume of the sodium hydroxide standard solution consumed in the blank test (unit: milliliter); M is the concentration of the sodium hydroxide standard solution (unit: mol / L); and W is the mass of the PVB sample added (unit: gram).

[0204]

[0205] 3. Resin yield test: calculated according to the formula: (total weight of PVB resin after drying (moisture content <1% wt) / (PVA feed amount + 0.75 x total butyraldehyde feed amount) x 100%.

[0206] 4. Butyraldehyde utilization rate test: butyraldehyde utilization rate = 72 * (m-m0) / (54 * m1), wherein m is the mass of polyvinyl butyral of the example, m0 is the mass of polyvinyl alcohol, and m1 is the mass of butyraldehyde.

[0207] 5. Yellow index test: according to the test requirements of HG / T6047-2022, 3.750 g of resin sample and 1.250 g of plasticizer compatible with PVB resin were stirred and mixed uniformly on an analytical balance. Paved on a 60 mm x 60 mm x 3 mm flat glass, pressed with the same glass, pressed into a 50 mm x 50 mm x 2 mm square block, then placed in a constant temperature drying oven at (200 ± 1 ℃), heated for two hours, taken out, cooled and ready for use, then tested according to the method specified in GB / T 2410.

[0208] Table 1

[0209]

[0210]

[0211] Compared with Example 4, the butyl aldehyde and 2-ethyl hexene aldehyde are not added in the suspension of Comparative Example 1, although the acetalization rate and butyl aldehyde utilization rate of the prepared PVB resin are improved to a certain extent, the acetalization rate and butyl aldehyde utilization rate of the PVB resin are still lower than those of Example 4, which shows that the use of the recycled PVB microparticles in the present application can significantly improve the acetalization rate of the finished product PVB, the suspension of Comparative Example 2 also does not include butyl aldehyde and 2-ethyl hexene aldehyde, although the polyvinyl butylal resin microparticles are increased by 1 part, the acetalization rate and butyl aldehyde utilization rate are also reduced, and the process route used in the present application does not need to add additional PVB crystal nucleus microparticles, so that the obtained PVB resin has good stability, which solves the problem in the prior art that the preparation process of PVB resin needs to add additional PVB crystal nucleus microparticles to improve the acetalization rate and butyl aldehyde utilization rate of the PVB resin, but which leads to poor stability of the PVB resin, in Comparative Example 3, the traditional method for preparing polyvinyl butylal resin in the prior art is used, since the polyvinyl butylal microparticles are directly added, the phenomenon of resin clumping and uneven dispersion occurs, which leads to a significant reduction in the acetalization rate, in Comparative Example 4, the average particle size of the polyvinyl butylal resin microparticles is increased, which leads to poor uniformity inside and outside the system, resulting in a reduction in the acetalization rate and butyl aldehyde utilization rate of the PVB resin, in Comparative Example 5, the amount of the suspension is increased, which reduces the acetalization rate and butyl aldehyde utilization rate of the PVB resin, in Comparative Example 6, the polyvinyl butylal resin microparticles in the suspension are increased, which leads to the phenomenon of resin climbing, and reduces the product yield, the acetalization rate and the butyl aldehyde utilization rate.

Claims

1. A method for producing a polyvinyl butyral resin, characterized by, The method comprises the following steps: (1) dissolving polyvinyl alcohol in water to obtain a PVA hydrogel; (2) adding the suspension into a feeding kettle, adjusting the pH value, then adding the PVA hydrogel and n-butyl aldehyde in a period of time, mixing and stirring to obtain a mixed solution; (3) transferring the mixed solution into a reaction kettle, heating and reacting for a period of time to obtain a second mixed solution, and the supernatant of the second mixed solution is recycled as the suspension in step (2); (4) adding water and an antioxidant into the second mixed solution, heating and reacting for a period of time to obtain a third mixed solution; (5) obtaining the polyvinyl butyral resin by solid-liquid separation, washing and drying the third mixed solution; The preparation raw materials of the polyvinyl butyral resin include, by weight, 200-600 parts of the suspension, 200-400 parts of polyvinyl alcohol, 150-250 parts of n-butyl aldehyde, 3-15 parts of inorganic acid, 1-5 parts of antioxidant, and 2000-4500 parts of water; The preparation raw materials of the suspension in step (2) include, by weight, 1-5 parts of polyvinyl butyral resin microparticles, 1-5 parts of an acidic catalyst, 50-200 parts of water, 0.1-0.5 parts of n-butyl aldehyde, and 0.01-0.05 parts of 2-ethylhexenaldehyde; The average particle size of the polyvinyl butyral resin microparticles is 5-30 μm. The acetalization rate of the polyvinyl butyral resin microparticles is not less than 60%.

2. The method for producing a polyvinyl butyral resin according to claim 1, characterized by, The inorganic acid is at least one of hydrochloric acid, sulfuric acid and nitric acid.

3. The method of producing a polyvinyl butyral resin according to claim 2, characterized by, The mass fraction of the inorganic acid is 10-40%.

4. The method of producing a polyvinyl butyral resin according to claim 1, characterized by, The polyvinyl alcohol has a polymerization degree of 1000-2000 and an alcoholysis degree of 85-99%.

5. The application of the polyvinyl butyral resin prepared by the method according to any one of claims 1-4 in the preparation of building safety glass, automobile front windshield glass and solar cell panel interlayer film.

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