Polyvinyl acetal resin composition, preparation method and laminated glass intermediate film

Abstract

The invention relates to the field of polyvinyl acetal resin products, in particular to a polyvinyl acetal resin composition, a preparation method and a laminated glass intermediate film. The polyvinyl acetal resin composition is used for manufacturing a laminated glass intermediate film and comprises first polyvinyl acetal resin and second polyvinyl acetal resin, the number of carbon atoms in an acetal group of the first polyvinyl acetal resin is 1-4, the number of carbon atoms in an acetal group of the second polyvinyl acetal resin is 1-4, and the number of carbon atoms in an acetal group of the second polyvinyl acetal resin is 1-4. The number of carbon atoms in an acetal group of the second polyvinyl acetal resin is 5-8; the ratio of strain hardening fracture work of the polyvinyl acetal resin composition is 20%-40%. According to the polyvinyl acetal resin composition, the preparation method and the laminated glass intermediate film provided by the invention, the strain hardening fracture work ratio of the polyvinyl acetal resin composition is 20-40%, and the laminated glass intermediate film prepared from the polyvinyl acetal resin composition has more excellent tear strength and impact resistance than a common PVB intermediate film.

Description

Technical Field

[0001] This invention relates to the field of polyvinyl acetal resin products, specifically to a polyvinyl acetal resin composition, preparation method, and interlayer film for laminated glass. Background Technology

[0002] Laminated glass is a composite glass product made of two or more sheets of glass with one or more layers of organic polymer interlayer sandwiched between them. After being processed by high temperature and high pressure, the glass and the interlayer are permanently bonded together. When the glass is impacted and breaks, the fragments are firmly held together by the interlayer, preventing them from flying and causing injury, and maintaining a certain degree of integrity. Therefore, it is called "safety glass".

[0003] Existing interlayer membranes generally include PVB (polyvinyl butyral) interlayer membranes, SGP (ionic gluconate interlayer membranes), and EVA (ethylene-vinyl acetate copolymer) interlayer membranes. Among them, PVB interlayer membranes are the most traditional and widely used, accounting for over 90% of the market share. SGP interlayer membranes are high-performance interlayer membranes with mechanical properties far superior to ordinary PVB interlayer membranes; their tear strength is 5 times that of PVB, and their penetration resistance is twice that of PVB. However, the price of SGP interlayer membranes is much higher than that of ordinary PVB interlayer membranes; typically, the price of SGP interlayer membranes is about 2 to 4 times that of ordinary PVB membranes. How to improve the tear strength and penetration resistance of PVB interlayer membranes is a key research and development focus.

[0004] To address the above issues, there is an urgent need to invent a polyvinyl alcohol acetal resin composition, its preparation method, and a laminated glass interlayer to solve the problems of low tear strength and penetration resistance of existing PVB interlayers. Summary of the Invention

[0005] The first aspect of the present invention provides a polyvinyl acetal resin composition, the first objective of which is to improve the performance of ordinary polyvinyl butyral resin powder.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution.

[0007] A polyvinyl acetal resin composition for manufacturing an interlayer film in laminated glass comprises a first polyvinyl acetal resin and a second polyvinyl acetal resin, wherein the first polyvinyl acetal resin has 1-4 carbon atoms in its acetal group, and the second polyvinyl acetal resin has 5-8 carbon atoms in its acetal group; the strain-hardening fracture work ratio of the polyvinyl acetal resin composition is 20%-40%. The strain hardening fracture work ratio is calculated as follows: The stress-strain curve of the polyvinyl acetal resin composition is obtained by testing it according to GB / T 1040.1 "Test of tensile properties of plastics - Part 1 - General Rules". The total area S is calculated by integrating the stress-strain curve. 总 The area S of the strain-hardening portion of the stress-strain curve is calculated by integrating the strain-hardening portion. 应 The strain hardening fracture work ratio W=S 应 / S 总 .

[0008] According to the polyvinyl acetal resin composition described above, the first polyvinyl acetal resin includes structural units represented by formula (1), and the second polyvinyl acetal resin includes structural units represented by formula (2): (1), (2), In this context, R1 represents an alkyl group with 2-3 carbon atoms, and R2 represents an alkyl group with 4-6 carbon atoms.

[0009] According to the above-described polyvinyl acetal resin composition, the first polyvinyl acetal resin is a condensation product of polyvinyl alcohol and butyraldehyde under acidic conditions, and the second polyvinyl acetal resin is a condensation product of polyvinyl alcohol and hexanal under acidic conditions. Butyraldehyde and hexanal both include their respective isomers.

[0010] According to the above-described polyvinyl acetal resin composition, the polyvinyl acetal resin composition is formed by the condensation of polyvinyl alcohol, butyraldehyde, and hexanal under acidic conditions.

[0011] According to the polyvinyl acetal resin composition described above, the yield strength of the polyvinyl acetal resin composition is above 35 MPa, and / or the elongation at break of the polyvinyl acetal resin composition is below 400%.

[0012] A second aspect of the present invention provides a method for preparing a polyvinyl acetal resin composition, the second objective of which is to prepare the polyvinyl acetal resin composition described above.

[0013] To achieve the above technical objectives, the present invention adopts the following technical solution.

[0014] A method for preparing a polyvinyl alcohol acetal resin composition includes dissolving polyvinyl alcohol in water to form a PVA aqueous solution, adding hydrochloric acid to the PVA aqueous solution to form an acidic system, and adding a mixed solution of butyraldehyde and hexanal to the acidic system.

[0015] According to the above-described method for preparing a polyvinyl alcohol acetal resin composition, the polyvinyl alcohol content in the PVA aqueous solution is 5-10 wt%, the pH value of the acidic system is 3-5, and the mass ratio of butyraldehyde to hexanal is 3:7~7:3.

[0016] The preparation method of the polyvinyl acetal resin composition described above includes the following steps: S1. Solution preparation: Prepare a PVA aqueous solution at 90°C-100°C, and prepare a mixed solution of butyraldehyde and hexanal according to the preset mass fraction ratio. S2. Establish an acidic reaction system: Lower the temperature of the PVA aqueous solution to 50°C-80°C, add hydrochloric acid solution with a concentration of 20%-28%; S3. Condensation reaction: Under the condition of maintaining the acidic reaction system at 10°C-18°C, continuously add a mixed solution of butyraldehyde and hexanal, with the dropping rate controlled at 10ml / min-20ml / min, until no more white precipitate is produced; S4. Post-processing: After washing with water and drying, the target product is obtained.

[0017] A third aspect of the present invention provides a laminated glass interlayer, and a third objective is to provide a high-performance laminated glass interlayer, particularly an interlayer with high tear strength and penetration resistance.

[0018] To achieve the above technical objectives, the present invention adopts the following technical solution.

[0019] A laminated glass interlayer comprises a polyvinyl acetal resin composition prepared by the method described above and a plasticizer.

[0020] According to the above-described interlayer glass film, the plasticizer is 5 to 30 parts by weight relative to 100 parts by weight of the polyvinyl acetal resin composition.

[0021] Compared with the prior art, the present invention has the following technical effects: The present invention provides a polyvinyl acetal resin composition, a preparation method, and a laminated glass interlayer. The polyvinyl acetal resin composition comprises a first polyvinyl acetal resin and a second polyvinyl acetal resin. The first polyvinyl acetal resin has 1-4 carbon atoms in its acetal group, and the second polyvinyl acetal resin has 5-8 carbon atoms in its acetal group. The strain-hardening fracture work ratio of the polyvinyl acetal resin composition is 20%-40%. Therefore, the laminated glass interlayer manufactured using this composition exhibits superior tear strength and impact resistance compared to ordinary PVB interlayers.

[0022] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 1 of the present invention is shown. 总 Schematic diagram; Figure 2 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 1 of the present invention is shown. 应 Schematic diagram; Figure 3 The tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 2 of the present invention is shown, with a total area S. 总 Schematic diagram; Figure 4 The tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 2 of the present invention is shown, with a total area S. 应 Schematic diagram; Figure 5 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 3 of the present invention is shown. 总 Schematic diagram; Figure 6 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 3 of the present invention is shown. 应 Schematic diagram; Figure 7 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 4 of the present invention is shown. 总 Schematic diagram; Figure 8 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film in Example 4 of the present invention is shown. 应 Schematic diagram; Figure 9 This diagram shows the tensile stress-strain curve of the polyvinyl acetal resin composition film of Comparative Example 2 of the present invention. Figure 10 The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film of Comparative Example 3 of the present invention is shown. 总 Schematic diagram; Figure 11The total area S of the tensile stress-strain curve of the polyvinyl acetal resin composition film of Comparative Example 3 of the present invention is shown. 应 Schematic diagram. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0027] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define polyvinyl acetal resin is merely for the purpose of distinguishing the corresponding polyvinyl acetal resin. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0028] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] A polyvinyl acetal resin composition for manufacturing an interlayer film in laminated glass comprises a first polyvinyl acetal resin and a second polyvinyl acetal resin, wherein the first polyvinyl acetal resin has 1-4 carbon atoms in its acetal group, and the second polyvinyl acetal resin has 5-8 carbon atoms in its acetal group; the strain-hardening fracture work ratio of the polyvinyl acetal resin composition is 20%-40%. The strain hardening fracture work ratio is calculated as follows: The stress-strain curve of the polyvinyl acetal resin composition is obtained by testing it according to GB / T 1040.1 "Test of tensile properties of plastics - Part 1 - General Rules". The total area S is calculated by integrating the stress-strain curve. 总 The area S of the strain-hardening portion of the stress-strain curve is calculated by integrating the strain-hardening portion. 应 The strain hardening fracture work ratio W=S 应 / S 总 .

[0030] In this embodiment, the first polyvinyl acetal resin is one of polyvinyl formal, polyvinyl acetal, polyvinyl propionate, and polyvinyl butyral, and the second polyvinyl acetal resin is one of polyvinyl pental, polyvinyl hexal, polyvinyl heptal, and polyvinyl octal.

[0031] Calculation of the proportion of strain-hardening fracture work in polyvinyl alcohol acetal resin compositions: A polyvinyl acetal resin composition film with a thickness of 0.72 mm is prepared using lamination or extrusion molding technology. Unless otherwise stated, the present invention uses extrusion molding technology to prepare the polyvinyl acetal resin composition film. Due to the influence of the preparation process and equipment, the thickness of the prepared polyvinyl acetal resin composition film is not strictly 0.72 mm. The thickness only needs to meet the test requirements of tensile properties. The preferred thickness of the present invention is 0.70 mm-0.73 mm.

[0032] Preparation of polyvinyl acetal resin composition film: 100 parts by weight of polyvinyl acetal resin powder and 30 parts of 3GO plasticizer are stirred evenly at room temperature and pressed into a film at 140-150℃.

[0033] Tensile property testing: Tensile specimens were prepared from the polyvinyl acetal resin composition film according to the test requirements of GB / T 1040.1 "Plastics - Tests for Tensile Properties - Part 1 - General Rules". Tensile tests were performed using a universal testing machine (maximum load 5kN) to obtain the tensile stress-strain curves. Please refer to... Figure 1 Total area S 总 This represents the integral area enclosed by the stress-strain curve and the horizontal axis; please refer to [link / reference]. Figure 2 S 应 This refers to the integral area under the strain-stress curve when a sample, after being necked during plastic deformation, is uniformly stretched again until fracture. The strain-hardening fracture work ratio is W=S. 应 / S 总。 In one specific embodiment, the first polyvinyl acetal resin includes structural units represented by formula (1), and the second polyvinyl acetal resin includes structural units represented by formula (2). (1), (2), In this context, R1 represents an alkyl group with 2-3 carbon atoms, and R2 represents an alkyl group with 4-6 carbon atoms.

[0034] Specifically, R1 and R2 both represent n-alkyl or isoalkyl, etc.

[0035] In one specific embodiment, the first polyvinyl acetal resin is a condensation product of polyvinyl alcohol and butyraldehyde under acidic conditions, and the second polyvinyl acetal resin is a condensation product of polyvinyl alcohol and hexanal under acidic conditions. Butyraldehyde and hexanal both include their respective isomers. For example, butyraldehyde is n-butyraldehyde or isobutyraldehyde, and hexanal is n-hexanal, 2-methylpentanal, 3-methylpentanal, and 4-methylpentanal.

[0036] In one specific embodiment, the polyvinyl acetal resin composition is formed by the condensation of polyvinyl alcohol, butyraldehyde, and hexanal under acidic conditions.

[0037] In one specific embodiment, the yield strength of the polyvinyl acetal resin composition is above 35 MPa; and / or the elongation at break of the polyvinyl acetal resin composition is below 400%; preferably, and / or the elongation at break of the polyvinyl acetal resin composition is below 200%.

[0038] A second aspect of the present invention provides a method for preparing a polyvinyl acetal resin composition, the second objective of which is to prepare the polyvinyl acetal resin composition described above.

[0039] To achieve the above technical objectives, the present invention adopts the following technical solution.

[0040] A method for preparing a polyvinyl alcohol acetal resin composition includes dissolving polyvinyl alcohol in water to form a PVA aqueous solution, adding hydrochloric acid to the PVA aqueous solution to form an acidic system, and adding a mixed solution of butyraldehyde and hexanal to the acidic system.

[0041] In one specific embodiment, the polyvinyl alcohol content in the PVA aqueous solution is 5-10 wt.% (unless otherwise specified in this application, wt.% refers to mass percentage), the pH value of the acidic system is 3-5, and the mass ratio of butyraldehyde to hexanal is 3:7 to 7:3.

[0042] In one specific embodiment, a method for preparing a polyvinyl acetal resin composition includes the following steps: S1. Solution preparation: Prepare a PVA aqueous solution at 90°C-100°C, and prepare a mixed solution of butyraldehyde and hexanal according to the preset mass fraction ratio. S2. Establish an acidic reaction system: Lower the temperature of the PVA aqueous solution to 50°C-80°C, add hydrochloric acid solution with a concentration of 20%-28%; S3. Condensation reaction: Under the condition of maintaining the acidic reaction system at 10°C-18°C, continuously add a mixed solution of butyraldehyde and hexanal, with the dropping rate controlled at 10ml / min-20ml / min, until no more white precipitate is produced; S4. Post-processing: After washing with water and drying, the target product is obtained.

[0043] A third aspect of the present invention provides a laminated glass interlayer, and a third objective is to provide a high-performance laminated glass interlayer, particularly an interlayer with high tear strength and penetration resistance.

[0044] To achieve the above technical objectives, the present invention adopts the following technical solution.

[0045] A laminated glass interlayer comprises a polyvinyl acetal resin composition prepared by the method described above and a plasticizer.

[0046] According to the above-described interlayer glass film, the plasticizer is 5 to 30 parts by weight relative to 100 parts by weight of the polyvinyl acetal resin composition.

[0047] Example 1 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 95±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution (23% concentration) was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. Then, a 70% hexanol solution and a 30% butyraldehyde solution were added dropwise (the 70% hexanol solution and 30% butyraldehyde solution refer to a mixed solution of 70 parts by weight of hexanol and 30 parts by weight of butyraldehyde, with the dropping rate controlled at 15±1 ml / min). After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0048] Example 2 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 95±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. Then, a 50% hexanol solution and a 50% butyraldehyde solution were added dropwise (the 50% hexanol solution and 50% butyraldehyde solution refer to a mixed solution of 50 parts by weight of hexanol and 50 parts by weight of butyraldehyde, with the dropping rate controlled at 15±1 ml / min). After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0049] Example 3 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 90±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. A 60% hexanol solution and a 40% butyraldehyde solution were then added dropwise (the 60% hexanol solution and 40% butyraldehyde solution refer to a mixed solution of 60 parts by weight of hexanol and 40 parts by weight of butyraldehyde, with the addition rate controlled at 15±1 ml / min). After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0050] Example 4 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 90±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. Then, a 30% hexanol solution and a 70% butyraldehyde solution were added dropwise (the 30% hexanol solution and 70% butyraldehyde solution refer to a mixed solution of 30 parts by weight of hexanol and 70 parts by weight of butyraldehyde, with the addition rate controlled at 15±1 ml / min). After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0051] Comparative Example 1 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 95±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. At this point, 10% hexanal solution and 90% butyraldehyde solution were added dropwise at a rate controlled at 15±1 ml / min. After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0052] Comparative Example 2 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 95±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. Hexanealdehyde solution was then added dropwise at a rate controlled at 15±1 ml / min until the product precipitated. The reaction was then maintained at this temperature for 1 hour. The product was washed with water and dried to obtain the final product.

[0053] Comparative Example 3 PVA was dissolved in water and prepared into an 8.0 wt.% solution at 90±1℃. The solution was then cooled until the temperature inside the reactor dropped to 30℃±2℃. Hydrochloric acid solution was added, and the temperature was further lowered until the temperature inside the reactor dropped to 15±2℃. At this point, 80% hexanal solution and 20% butyraldehyde solution were added dropwise at a rate controlled at 15±1 ml / min. After the product precipitated, the reaction was maintained at this temperature for 1 hour. The product was then washed with water and dried to obtain the final product.

[0054] Preparation of intermediate membrane 100 parts by weight of the final product (polyvinyl acetal resin composition or polyvinyl alcohol) obtained in the examples or comparative examples, 30 parts by weight of plasticizer (3G0 or 3G8, etc., 3G0 is used in this invention), and 0.12 parts by weight of antioxidant are thoroughly mixed. The thoroughly mixed material is added to an extruder for extrusion molding. The specific extrusion process adopts the extrusion process of the prior art.

[0055] Preparation of laminated glass Take two pieces of glass of the same size (the size of the glass needs to meet the requirements of subsequent testing; green or white glass can be used). Insert an interlayer between the two pieces of glass and remove any air remaining between the glass and the interlayer by applying pressure rollers or by placing a rubber bag under reduced pressure. Then, pre-bond the laminate at approximately 70–110°C to obtain a laminate. Next, place the laminate in an autoclave or press it at approximately 120–150°C and 1–1.5 MPa for bonding. This process yields laminated glass.

[0056] Performance testing Tear strength The tear strength of the interlayer was tested according to GB / T 16578.1 "Determination of tear resistance of plastic films and sheets - Part 1: Pants-shaped tear test".

[0057] Adhesion and penetration resistance The laminated glass prepared according to GB 15763.3-2009 "Safety Glass for Building - Part 3: Laminated Glass" was tested for adhesive strength and penetration resistance. A falling ball impact peel test was used, in which a 2260g, 82.5mm diameter quenched steel ball was placed at a height of 4.8m above the sample surface. After free fall, the impact point should be located within a circle with a radius of 25mm centered on the geometric center of the sample, and the condition of the glass was observed.

[0058] Criteria for determining adhesion and penetration resistance √√: No obvious blocky glass (area greater than 1 square centimeter) is separated from the interlayer; √: There are at most two pieces of glass with an area greater than 1 square centimeter and less than 2 square centimeters that have delaminated from the interlayer; ×: A steel ball penetrates the laminated glass.

[0059] Table 1 The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyvinyl acetal resin composition, characterized in that, The polyvinyl acetal resin composition is used to manufacture an interlayer film for laminated glass, comprising a first polyvinyl acetal resin and a second polyvinyl acetal resin, wherein the first polyvinyl acetal resin has 1-4 carbon atoms in its acetal group, and the second polyvinyl acetal resin has 5-8 carbon atoms in its acetal group; the strain-hardening fracture work ratio of the polyvinyl acetal resin composition is 20%-40%. The strain hardening fracture work ratio is calculated as follows: The stress-strain curve of the polyvinyl acetal resin composition is obtained by testing it according to GB / T 1040.1 "Test of tensile properties of plastics - Part 1 - General Rules". The total area S is calculated by integrating the stress-strain curve. 总 The area S of the strain-hardening portion of the stress-strain curve is calculated by integrating the strain-hardening portion. 应 The strain hardening fracture work ratio W=S 应 / S 总 .

2. The polyvinyl acetal resin composition according to claim 1, characterized in that, The first polyvinyl acetal resin includes structural units represented by formula (1), and the second polyvinyl acetal resin includes structural units represented by formula (2). （1）， （2）， In this context, R1 represents an alkyl group with 2-3 carbon atoms, and R2 represents an alkyl group with 4-6 carbon atoms.

3. A polyvinyl acetal resin composition according to claim 1 or 2, characterized in that, The first polyvinyl alcohol acetal resin is a condensation product of polyvinyl alcohol and butyraldehyde under acidic conditions, and the second polyvinyl alcohol acetal resin is a condensation product of polyvinyl alcohol and hexanal under acidic conditions. Butyraldehyde and hexanal both include their respective isomers.

4. The polyvinyl acetal resin composition according to claim 3, characterized in that, The polyvinyl alcohol acetal resin composition is formed by the condensation of polyvinyl alcohol, butyraldehyde, and hexanal under acidic conditions.

5. The polyvinyl acetal resin composition according to claim 4, characterized in that, The polyvinyl acetal resin composition has a yield strength of 35 MPa or higher, and / or an elongation at break of 400% or lower.

6. A method for preparing the polyvinyl acetal resin composition according to claim 4 or 5, characterized in that, This includes dissolving polyvinyl alcohol in water to form an aqueous PVA solution, adding hydrochloric acid to the aqueous PVA solution to form an acidic system, and adding a mixed solution of butyraldehyde and hexanal to the acidic system.

7. The method for preparing a polyvinyl acetal resin composition according to claim 6, characterized in that, The polyvinyl alcohol content in the PVA aqueous solution is 5-10 wt%, the pH value of the acidic system is 3-5, and the mass ratio of butyraldehyde to hexanal is 3:7~7:

3.

8. The method for preparing a polyvinyl acetal resin composition according to claim 7, characterized in that, Includes the following steps: S1. Solution preparation: Prepare a PVA aqueous solution at 90°C-100°C, and prepare a mixed solution of butyraldehyde and hexanal according to the preset mass fraction ratio. S2. Establish an acidic reaction system: Lower the temperature of the PVA aqueous solution to 50°C-80°C, add hydrochloric acid solution with a concentration of 20%-28%; S3. Condensation reaction: Under the condition of maintaining the acidic reaction system at 10°C-18°C, continuously add a mixed solution of butyraldehyde and hexanal, with the dropping rate controlled at 10ml / min-20ml / min, until no more white precipitate is produced; S4. Post-processing: After washing with water and drying, the target product is obtained.

9. A laminated glass interlayer, characterized in that, It includes a polyvinyl acetal resin composition prepared by the method for preparing the polyvinyl acetal resin composition according to claims 6-8 and a plasticizer.

10. The interlayer film of laminated glass according to claim 9, characterized in that, The plasticizer is 5 to 30 parts by weight relative to 100 parts by weight of the polyvinyl acetal resin composition.

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