Composite heat stabilizer as well as PVB (polyvinyl butyral) resin and application thereof

Abstract

The invention discloses a composite heat stabilizer and PVB resin and application thereof, and belongs to the technical field of polyvinyl butyral materials, the composite heat stabilizer is prepared from the following raw materials in parts by weight: 1-5 parts of lanthanum hexaboride, 0.5-2 parts of cerium oxide, 0.3-0.8 part of tantalum selenide and 10-20 parts of silicon dioxide. The PVB resin is prepared from the composite heat stabilizer, and the application refers to the application of the composite heat stabilizer in preparation of the PVB resin. The composite heat stabilizer provided by the invention can significantly improve the heat stability of PVB, and also has a certain improvement effect on the comprehensive performance of PVB.

Description

Technical Field

[0001] The invention belongs to the technical field of polyvinyl butyral (PVB) materials, and in particular relates to a composite heat stabilizer and a PVB resin and application thereof. Background Art

[0002] Polyvinyl butyral (PVB for short) is a synthetic resin made by the condensation reaction of n-butyraldehyde and polyvinyl alcohol (PVA) aqueous solution under the action of a catalyst. It has the properties of transparency, light resistance, water resistance, film-forming and impact resistance. It has good bonding properties to materials such as glass, metal, wood, ceramics, leather and fiber, and is therefore widely used.

[0003] However, due to the poor thermal stability of polyvinyl butyral, it is easy to degrade during the processing of the product. For example, during the processing of the middle layer of safety glass, the film is easy to yellow. Therefore, improving the thermal stability of polyvinyl butyral resin has always been the focus of attention.

[0004] CN105001359A discloses a method for preparing polyvinyl butyral, which uses polyvinyl alcohol with a degree of alcoholysis of 97.0-98.5% as a raw material, dissolves in deionized water and then cools, first reacts polyvinyl alcohol with a portion of n-butyraldehyde at low temperature under the catalysis of inorganic acid, then adds the remaining n-butyraldehyde to continue to react with polyvinyl alcohol, and then heats to 50-70°C at a heating rate of 8-12°C / h to fully acetalize, and after the reaction is completed, separates polyvinyl butyral and acidic liquid by a centrifuge, washes the separated polyvinyl butyral with deionized water and a dilute alkaline solution in a vacuum filtration washing machine, and then centrifuges and airflow dry to obtain polyvinyl butyral. The polyvinyl butyral obtained by the invention does not turn yellow in 1.5 hours at a high temperature of 180°C, and the thermal stability is improved. CN114920860A discloses a heat-resistant PVB resin, comprising n-butyraldehyde, polyvinyl alcohol, hydrochloric acid, a solvent, and an extender, wherein the extender comprises, by weight percentage, 9.4-10.4% of cuprous iodide, 14.5-15.5% of lanthanum hexaboride, 1.7-2.7% of nano titanium dioxide, 24.6-25.6% of natural attapulgite, and the remainder is anhydrous ethanol. The invention can effectively improve the heat resistance of the PVB resin by adding the extender, ensure that the PVB resin is used normally, avoid yellowing caused by thermal oxidation degradation, and ensure the stability of the PVB resin.

[0005] PVB can be used in the interlayer of safety glass. It has the characteristics of high transparency, high adhesion, impact resistance and penetration resistance. It has good bonding properties for materials such as glass, metal, wood, ceramics, leather and fiber. When used in safety glass, it can prevent the glass from being broken into pieces and injuring people when it is hit by external forces. Similarly, this type of laminated glass is more commonly used in high-end cars and high-rise buildings, and its usage has shown a significant upward trend in recent years. Although the above-mentioned PVB resin has improved the thermal stability problem to a certain extent, its comprehensive performance still has room for improvement. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a composite heat stabilizer and its PVB resin and application. The composite heat stabilizer of the present invention can significantly improve the thermal stability of PVB and at the same time has a certain improvement effect on the comprehensive performance of PVB.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a composite thermal stabilizer, comprising the following raw materials by weight: 1-5 parts of lanthanum hexaboride, 0.5-2 parts of cerium oxide, 0.3-0.8 parts of tantalum selenide and 10-20 parts of silicon dioxide.

[0009] Preferably, the composition comprises 3-5 parts of lanthanum hexaboride, 0.5-1 parts of cerium oxide, 0.4-0.6 parts of tantalum selenide and 12-18 parts of silicon dioxide.

[0010] More preferably, the composition comprises 4 parts of lanthanum hexaboride, 1 part of cerium oxide, 0.5 parts of tantalum selenide and 16 parts of silicon dioxide.

[0011] In a second aspect, the present invention provides a method for preparing the composite thermal stabilizer, comprising the following steps:

[0012] Step 1, mixing the formulated amounts of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide, adding water and ball milling to obtain a slurry;

[0013] Step 2, stirring tetrabutyl titanate, diethanolamine, water and ethanol to form a sol;

[0014] Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2 for ultrasonic treatment, adding urea and hydrochloric acid and performing a second ultrasonic treatment to form a gel solution;

[0015] Step 4: filtering, roasting and crushing the glue solution obtained in step 3 to obtain the composite thermal stabilizer.

[0016] Preferably, the amount of water added in step 1 is 5-10% of the total amount of lanthanum hexaboride, cerium oxide and silicon dioxide, and more preferably 8%.

[0017] Preferably, the median particle size D50 of the slurry in step 1 is 5-35 μm; more preferably 10-20 μm.

[0018] Preferably, the molar ratio of tetrabutyl titanate, diethanolamine, water and ethanol in step 2 is 1:1-1.5:1-2:25-35; more preferably 1:1.2:1.5:30.

[0019] Preferably, the ultrasonic treatment in step 3 is carried out at 35-40° C. and 300-500 W for 5-10 min.

[0020] Preferably, the molar ratio of tetrabutyl titanate to silicon dioxide in step 3 is 1:0.1-0.3; more preferably 1:0.2.

[0021] Preferably, the molar ratio of tetrabutyl titanate, urea and hydrochloric acid in step 3 is 1:0.2-0.5:0.01-0.02.

[0022] Preferably, the conditions for the secondary ultrasonic treatment in step 3 are: ultrasonic treatment at 35-40° C. and 300-500 W for 15-30 min.

[0023] Preferably, the filtration in step 4 is through a 0.45 μm filter membrane.

[0024] Preferably, the calcination in step 4 is: calcination at 500-600° C. for 1-3 hours.

[0025] In a third aspect, the present invention provides use of the composite heat stabilizer prepared by the above preparation method in the preparation of PVB resin.

[0026] In a fourth aspect, the present invention provides a method for preparing a PVB resin, comprising the following steps:

[0027] S1, dissolving polyvinyl alcohol in water to obtain a polyvinyl alcohol solution;

[0028] S2, adding n-butyraldehyde, a composite heat stabilizer and hydrochloric acid to the polyvinyl alcohol solution obtained in step S1 to react and obtain a crude PVB product;

[0029] S3, filtering and washing the crude PVB obtained in step S2, adding alkali for stabilization, separating the solid from the liquid, and drying to obtain the PVB resin.

[0030] In a fifth aspect, the present invention provides a PVB product, wherein the PVB product is made of the aforementioned PVB resin.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The composite heat stabilizer prepared by the present invention can significantly improve the thermal stability of PVB. At the same time, the composite heat stabilizer of the present invention can also improve the comprehensive properties of PVB film such as thermal shrinkage, clarity, haze and thermal insulation performance.

[0033] (2) The preparation method of the PVB resin of the present invention is simple, low-cost, and suitable for large-scale production.

[0034] (3) The PVB film prepared by the present invention meets the requirements of polyvinyl butyral (PVB) film for laminated glass and can be used in automobile production. DETAILED DESCRIPTION

[0035] The following examples are only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present invention, the present invention may also be subjected to several improvements and modifications, which also fall within the scope of protection of the claims of the present invention. The following description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. It will be apparent to professionals and technicians in this field that various modifications to these embodiments, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but may be applied to a wider range consistent with the principles and novel features disclosed herein. Although any methods and materials similar or equivalent to those described in the present invention may be used in the implementation or testing of the present invention, preferred methods and materials are listed herein.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0037] Example 1 Composite heat stabilizer

[0038] The composite heat stabilizer comprises 4 parts of lanthanum hexaboride, 1 part of cerium oxide, 0.5 parts of tantalum selenide and 16 parts of silicon dioxide in parts by weight.

[0039] The preparation method is:

[0040] Step 1, mixing the formulated amounts of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide, adding water (8% of the total amount of lanthanum hexaboride, cerium oxide and silicon dioxide) and ball milling to obtain a slurry with a median particle size D50 of 15 μm;

[0041] Step 2, tetrabutyl titanate, diethanolamine, water and ethanol were mixed in a molar ratio of 1:1.2:1.5:30, and stirred at 500 rpm for 15 minutes to form a sol;

[0042] Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2, ultrasonically treating (ultrasonic treating at 400W for 7min at 37±2°C), and then adding urea and hydrochloric acid for a second ultrasonic treatment (ultrasonic treating at 400W for 20min at 37±2°C) to form a glue solution, wherein the molar ratio of tetrabutyl titanate to silicon dioxide in the glue solution is 1:0.2, and the molar ratio of tetrabutyl titanate, urea and hydrochloric acid is 1:0.3:0.01;

[0043] Step 4: Filter the glue solution obtained in step 3 through a 0.45 μm filter membrane, calcine the solid phase at 550° C. for 2 hours, and crush to obtain the composite thermal stabilizer.

[0044] Example 2 Composite heat stabilizer

[0045] The composite heat stabilizer has a formula of 3 parts by weight of lanthanum hexaboride, 0.5 parts by weight of cerium oxide, 0.4 parts by weight of tantalum selenide and 12 parts by weight of silicon dioxide.

[0046] The preparation method is the same as Example 1.

[0047] Example 3 Composite heat stabilizer

[0048] The composite heat stabilizer has a formula of 5 parts by weight of lanthanum hexaboride, 1 part by weight of cerium oxide, 0.6 parts by weight of tantalum selenide and 18 parts by weight of silicon dioxide.

[0049] The preparation method is the same as Example 1.

[0050] Example 4 Composite heat stabilizer

[0051] The composite heat stabilizer has a formula of: 1 part of lanthanum hexaboride, 0.5 part of cerium oxide, 0.3 part of tantalum selenide and 10 parts of silicon dioxide in parts by weight.

[0052] The preparation method is:

[0053] Step 1, mixing the formulated amounts of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide, adding water (5% of the total amount of lanthanum hexaboride, cerium oxide and silicon dioxide) and ball milling to obtain a slurry with a median particle size D50 of 5 μm;

[0054] Step 2, tetrabutyl titanate, diethanolamine, water and ethanol were mixed in a molar ratio of 1:1:1:25, and stirred at 500 rpm for 15 minutes to form a sol;

[0055] Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2, ultrasonically treating (ultrasonic treating at 400W for 7min at 37±2°C), and then adding urea and hydrochloric acid for a second ultrasonic treatment (ultrasonic treating at 400W for 20min at 37±2°C) to form a glue solution, wherein the molar ratio of tetrabutyl titanate to silicon dioxide in the glue solution is 1:0.1, and the molar ratio of tetrabutyl titanate, urea and hydrochloric acid is 1:0.2:0.01;

[0056] Step 4: Filter the glue solution obtained in step 3 through a 0.45 μm filter membrane, calcine the solid phase at 550° C. for 2 hours, and crush to obtain the composite thermal stabilizer.

[0057] Example 5 Composite heat stabilizer

[0058] The formula of the composite heat stabilizer is: 5 parts of lanthanum hexaboride, 2 parts of cerium oxide, 0.8 parts of tantalum selenide and 20 parts of silicon dioxide in parts by weight.

[0059] The preparation method is:

[0060] Step 1, mixing the formulated amounts of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide, adding water (10% of the total amount of lanthanum hexaboride, cerium oxide and silicon dioxide) and ball milling to obtain a slurry with a median particle size D50 of 35 μm;

[0061] Step 2, tetrabutyl titanate, diethanolamine, water and ethanol were mixed in a molar ratio of 1:1.5:2:35, and stirred at 500 rpm for 15 minutes to form a sol;

[0062] Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2, ultrasonically treating (ultrasonic treating at 400W for 7min at 37±2°C), and then adding urea and hydrochloric acid for a second ultrasonic treatment (ultrasonic treating at 400W for 20min at 37±2°C) to form a glue solution, wherein the molar ratio of tetrabutyl titanate to silicon dioxide in the glue solution is 1:0.3, and the molar ratio of tetrabutyl titanate, urea and hydrochloric acid is 1:0.5:0.02;

[0063] Step 4: Filter the glue solution obtained in step 3 through a 0.45 μm filter membrane, calcine the solid phase at 550° C. for 2 hours, and crush to obtain the composite thermal stabilizer.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that the formula of the composite heat stabilizer is different.

[0066] Specifically, the formula of the composite heat stabilizer is: 6 parts of lanthanum hexaboride, 0.3 parts of cerium oxide, 1.2 parts of tantalum selenide and 14 parts of silicon dioxide.

[0067] The preparation method is the same as Example 1.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that the formula of the composite heat stabilizer is different.

[0070] Specifically, the formula of the composite heat stabilizer is: 0.5 parts of lanthanum hexaboride, 4 parts of cerium oxide, 0.2 parts of tantalum selenide and 16 parts of silicon dioxide.

[0071] The preparation method is the same as Example 1.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 1 is that the formula of the composite heat stabilizer is different.

[0074] The composite heat stabilizer comprises 4 parts of rubidium hexaboride, 1 part of zirconium oxide, 0.5 parts of tantalum oxide and 16 parts of silicon dioxide in parts by weight.

[0075] The preparation method is:

[0076] Step 1, mixing the formulated amounts of rubidium hexaboride, zirconium oxide, tantalum selenide and silicon dioxide, adding water (8% of the total amount of rubidium hexaboride, zirconium oxide, tantalum selenide and silicon dioxide) and ball milling to obtain a slurry with a median particle size D50 of 15 μm;

[0077] Step 2, tetrabutyl titanate, diethanolamine, water and ethanol were mixed in a molar ratio of 1:1.2:1.5:30, and stirred at 500 rpm for 15 minutes to form a sol;

[0078] Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2, ultrasonically treating (ultrasonic treating at 400W for 7min at 37±2°C), and then adding urea and hydrochloric acid for a second ultrasonic treatment (ultrasonic treating at 400W for 20min at 37±2°C) to form a glue solution, wherein the molar ratio of tetrabutyl titanate to silicon dioxide in the glue solution is 1:0.2, and the molar ratio of tetrabutyl titanate, urea and hydrochloric acid is 1:0.3:0.01;

[0079] Step 4: Filter the glue solution obtained in step 3 through a 0.45 μm filter membrane, calcine the solid phase at 550° C. for 2 hours, and crush to obtain the composite thermal stabilizer.

[0080] 1. Performance test of PVB resin

[0081] 1. Preparation of PVB resin:

[0082] S1. Soak 30 kg of 1799 PVA (1799 means polymerization degree 1700, alcoholysis degree 99%) in pure water for 30 min, then heat to 85°C and dissolve for 1.5 hours. After dissolution, keep warm for 2 hours to prepare an 11% PVA solution.

[0083] S2, cooling the PVA solution obtained in step S1 to 10°C, adding 17kg of n-butyraldehyde and 0.1kg of composite heat stabilizer, stirring at 1000rpm for 10min, adding 28kg of 16wt% hydrochloric acid, heating to 35°C and keeping warm for 1 hour to obtain a crude PVB product.

[0084] S3. Wash the crude PVB obtained in step S2 with pure water until it is neutral, add 40 wt % sodium hydroxide to adjust the pH value to 11, stabilize it for 8 hours, wash it with water until the pH value is 8, centrifuge it to dry it, and dry it to obtain PVB resin.

[0085] The composite heat stabilizers prepared in Examples 1-5 and Comparative Examples 1-3 were used to prepare the corresponding PVB resins, and the effects of different composite heat stabilizers on the properties of the PVB resins were investigated.

[0086] 2. Baking test

[0087] Test method: Weigh 5 grams of PVB resin powder sample, spread it on a glass slide with a thickness of about 1 mm, bake it in an oven at 180°C for 60 minutes, take it out and cool it down, and observe the appearance of the baked resin powder. The results are shown in Table 1 below.

[0088] Table 1

[0089] Composite heat stabilizer Appearance PVB resin 0 none Obvious yellowing PVB resin 1 Example 1 No yellowing PVB resin 2 Example 2 No yellowing PVB resin 3 Example 3 No yellowing PVB resin 4 Example 4 No yellowing PVB resin 5 Example 5 No yellowing PVB resin 6 Comparative Example 1 Obvious yellowing PVB resin 7 Comparative Example 2 Obvious yellowing PVB resin 8 Comparative Example 3 Obvious yellowing

[0090] The results show that compared with PVB resin 0 without adding the composite heat stabilizer, PVB resins 1-5 with the composite heat stabilizer added did not turn yellow, indicating that the composite heat stabilizers provided in Examples 1 to 5 of the present invention can prevent the PVB resin from turning yellow at high temperatures and have good thermal stability.

[0091] 2. Performance test of PVB film

[0092] 1. Preparation of PVB film

[0093] S1, 3 parts by weight of PVB resin and 1 part by weight of plasticizer were mixed and extruded through an extruder (inlet temperature 45° C., outlet temperature 165° C.);

[0094] S2. Use a water cooling process (water temperature 20° C.) to cool and shape the extruded PVB film to obtain a PVB film.

[0095] 2. Performance Testing

[0096] PVB resin 0-PVB resin 7 were used to prepare the corresponding PVB films 0-PVB film 7, and the effects of different composite heat stabilizers on the properties of PVB films were investigated.

[0097] The specific methods or reference standards are as follows:

[0098] 1) Thermal shrinkage: measured according to the standard for polyvinyl butyral (PVB) film for laminated glass (JC / T2166-2013), the thermal shrinkage is required to be ≤8.0%.

[0099] 2) Visible light projection ratio and haze: Tested according to the polyvinyl butyral (PVB) film for laminated glass (JC / T2166-2013), requiring the visible light projection ratio to be ≥85% and the haze to be <0.6%.

[0100] 3) Tensile strength and elongation at break: measured in accordance with polyvinyl butyral (PVB) film for laminated glass (JC / T2166-2013); tensile strength ≥ 20.0 MPa, elongation at break ≥ 200%.

[0101] 4) Infrared blocking rate IR: Use LS182 solar film tester for testing.

[0102] The performance test results of PVB film are shown in Table 2.

[0103] Table 2

[0104]

[0105] The results show that the PVB films 1-5 prepared by using the composite heat stabilizer prepared in Examples 1-5 of the present invention have a heat shrinkage of less than 6% at a thickness of 0.76 mm, a visible light projection ratio of more than 85%, a haze of less than 0.5%, a tensile strength of more than 20 MPa, an elongation at break of more than 200%, and an infrared blocking rate (950 nm) of more than 44%, indicating that the PVB film prepared by the present invention meets the requirements of polyvinyl butyral (PVB) film for laminated glass, and has comprehensive properties such as low haze, high clarity, and good thermal insulation performance.

[0106] The difference between PVB films 6 and 7 and PVB film 1 is that the dosage relationship of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide in the composite heat stabilizer is different. According to the test results, the PVB films 6 and 7 prepared by the composite heat stabilizer composed of the conventional dosage relationship of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide have a heat shrinkage rate of >8% and a visible light projection ratio of <85%, which cannot meet the requirements of polyvinyl butyral (PVB) film for laminated glass. It can be seen that in the present invention, only lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide in a specific dosage relationship can improve the comprehensive performance of PVB film while ensuring that other properties meet the requirements.

[0107] The only difference between PVB film 8 and PVB film 1 is that rubidium hexaboride, zirconium oxide and tantalum oxide are used to replace lanthanum hexaboride, cerium oxide and tantalum selenide in the composite heat stabilizer. According to the test results, the PVB film 8 prepared by the composite heat stabilizer composed of rubidium hexaboride, zirconium oxide, tantalum oxide and silicon dioxide has a heat shrinkage rate of more than 8% and a visible light projection ratio of less than 85%, which cannot meet the requirements of polyvinyl butyral (PVB) film for laminated glass.

[0108] The above is a further description of the present invention in conjunction with specific embodiments, but these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

Claims

1. A composite heat stabilizer, characterized in that: The raw materials include the following by weight: 1-5 parts of lanthanum hexaboride, 0.5-2 parts of cerium oxide, 0.3-0.8 parts of tantalum selenide and 10-20 parts of silicon dioxide.

2. The composite heat stabilizer according to claim 1, characterized in that The raw materials include the following by weight: 3-5 parts of lanthanum hexaboride, 0.5-1 parts of cerium oxide, 0.4-0.6 parts of tantalum selenide and 12-18 parts of silicon dioxide.

3. The composite heat stabilizer according to claim 1, characterized in that The raw materials include the following by weight: 4 parts of lanthanum hexaboride, 1 part of cerium oxide, 0.5 parts of tantalum selenide and 16 parts of silicon dioxide.

4. The method for preparing the composite thermal stabilizer according to any one of claims 1 to 3, characterized in that: The steps include: Step 1, mixing the formulated amounts of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide, adding water and ball milling to obtain a slurry; Step 2, stirring tetrabutyl titanate, diethanolamine, water and ethanol to form a sol; Step 3, adding the slurry obtained in step 1 to the sol obtained in step 2 for ultrasonic treatment, adding urea and hydrochloric acid and performing a second ultrasonic treatment to form a gel solution; Step 4: filtering, roasting and crushing the glue solution obtained in step 3 to obtain the composite thermal stabilizer.

5. The preparation method according to claim 4, characterized in that: The amount of water added in step 1 is 5-10% of the total amount of lanthanum hexaboride, cerium oxide, tantalum selenide and silicon dioxide; and / or, the median particle size D50 of the slurry in step 1 is 5-35 μm; And / or, the molar ratio of tetrabutyl titanate, diethanolamine, water and ethanol in step 2 is 1:1-1.5:1-2:25-35.

6. The preparation method according to claim 4, characterized in that: The conditions of the ultrasonic treatment in step 3 are: ultrasonic treatment at 300-500W for 5-10 min at 35-40°C; And / or, the molar ratio of tetrabutyl titanate to silicon dioxide in step 3 is 1:0.1-0.3; And / or, the molar ratio of tetrabutyl titanate, urea and hydrochloric acid in step 3 is 1:0.2-0.5:0.01-0.02; And / or, the conditions of the secondary ultrasonic treatment in step 3 are: ultrasonic treatment at 35-40° C. and 300-500 W for 15-30 min.

7. Use of the composite heat stabilizer according to any one of claims 1 to 3 or the composite heat stabilizer prepared by the preparation method according to any one of claims 4 to 6 in the preparation of PVB resin.

8. A PVB resin, characterized in that: The composite heat stabilizer is made from the composite heat stabilizer described in any one of claims 1 to 3 or the composite heat stabilizer prepared by the preparation method described in any one of claims 4 to 6.

9. The method for preparing the PVB resin according to claim 8, characterized in that: The steps include: S1, dissolving polyvinyl alcohol in water to obtain a polyvinyl alcohol solution; S2, adding n-butyraldehyde, a composite heat stabilizer and hydrochloric acid to the polyvinyl alcohol solution obtained in step S1 to react and obtain a crude PVB product; S3, filtering and washing the crude PVB obtained in step S2, adding alkali for stabilization, separating the solid from the liquid, and drying to obtain the PVB resin.

10. A PVB product, characterized in that: The invention is made of the PVB resin described in claim 8 or the PVB resin prepared by the preparation method described in claim 9.

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