Heat-strengthened laminated glass and preparation method thereof

Abstract

The invention relates to heat-strengthened laminated glass and a preparation method thereof, and belongs to the technical field of laminated glass. The preparation method comprises the following steps: firstly, carrying out nucleophilic acyl substitution reaction on 4-(chlorocarbonyl) benzoic acid and p-hydroxystyrene, and then carrying out Fourier rearrangement to obtain the ultraviolet light absorber with an o-hydroxybenzophenone structure; then carrying out esterification reaction on the obtained ultraviolet light absorber and 3-hydroxy methyl nonanoate to obtain a plasticizer precursor; the plasticizer precursor and 3-aminopropyltriethoxysilane are combined through an addition reaction between double bonds and amino groups, and a modified plasticizer is obtained; and finally, blending and extruding the modified plasticizer and polyvinyl butyral resin, calendaring to form a film, and laminating with a thermally strengthened glass plate to obtain the thermally strengthened laminated glass with strengthened performance.

Description

Technical Field

[0001] This invention belongs to the field of laminated glass technology, specifically, it relates to a heat-strengthened laminated glass and its preparation method. Background Technology

[0002] Heat-strengthened laminated glass, with its excellent impact resistance, safety protection performance, and optical transparency, is widely used in many fields such as building curtain walls, automotive windshields, and high-speed rail windows. The core structure of this type of glass consists of a heat-strengthened glass sheet and a polyvinyl butyral (PVB) resin interlayer. In practical applications, heat-strengthened laminated glass is exposed to the natural environment for extended periods, inevitably suffering from continuous exposure to ultraviolet radiation from sunlight. This causes the interlayer to age, exhibiting yellowing, embrittlement, and decreased elasticity, severely affecting the optical clarity of the laminated glass and weakening the bond strength between the PVB interlayer and the glass. Ultimately, this leads to a significant reduction in the impact resistance and penetration resistance of the laminated glass, posing a significant safety hazard.

[0003] To address these issues, existing technologies typically employ the addition of UV absorbers to PVB resin. However, traditional o-hydroxybenzophenone-based UV absorbers only exhibit physical mixing with PVB resin and plasticizers, lacking a stable chemical bond. During long-term use of laminated glass, UV absorbers are prone to migration and precipitation, leading to a rapid decline in UV resistance over time, failing to achieve long-term stable protection. Furthermore, plasticizers, as a crucial component of the PVB interlayer, are independent functional components of the UV absorbers, exhibiting poor compatibility and a tendency to phase separation. This not only affects the optical properties of the PVB interlayer but also further exacerbates the migration problem of the UV absorbers.

[0004] Therefore, developing a PVB interlayer modification technology that can achieve synergistic optimization of plasticization and UV resistance is an important goal for upgrading the performance of thermally strengthened laminated glass. Summary of the Invention

[0005] The purpose of this invention is to provide a heat-strengthened laminated glass and its preparation method, in order to solve the problems mentioned in the background art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing heat-strengthened laminated glass includes the following steps:

[0008] Step 1: Under ice-water bath conditions, p-hydroxystyrene, 4-(chlorocarbonyl)benzoic acid, and pyridine are mixed in a reaction vessel and stirred until homogeneous. The ice-water bath is then removed, and the mixture is reacted at room temperature for 2-3 hours. After the reaction is complete, the reaction solution is poured into ice water, and then dilute hydrochloric acid solution is added to adjust the pH to 2-3. The solid is then obtained by filtration, washed with deionized water, and dried. The obtained solid is then mixed with aluminum chloride and dichlorobenzene and reacted at 130-160℃ for 4-6 hours. After the reaction is complete, the mixture is cooled to room temperature and then concentrated by rotary evaporation. The concentrated solution is then poured into dichloromethane, and finally, the solvent is removed by rotary evaporation to obtain the ultraviolet absorber.

[0009] Step 2: Mix the ultraviolet absorber, methyl 3-hydroxynonanoate, p-toluenesulfonic acid, and N,N-dimethylformamide in a reaction vessel, stir until homogeneous, heat to 50-60℃ and react for 4-6 hours. After the reaction is complete, cool to room temperature, then pour the reaction solution into ice water, filter to obtain a solid, and wash successively with saturated sodium bicarbonate solution and deionized water, and dry to obtain the plasticizer precursor.

[0010] The third step involves mixing the plasticizer precursor, 3-aminopropyltriethoxysilane, and toluene in a reaction vessel, stirring until homogeneous, and reacting at 55-65℃ for 4-6 hours. After the reaction is complete, the mixture is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain the modified plasticizer.

[0011] Step 4: The modified plasticizer and polyvinyl butyral resin are blended, extruded, and calendered into a film, which is then covered on the first heat-strengthened glass plate. Subsequently, a second heat-strengthened glass plate is covered on top to obtain a laminated glass plate. The laminated glass plate is then pre-pressed in a pre-pressing machine, and finally placed in an autoclave for hot pressing and bonding. After cooling, it is removed to obtain heat-strengthened laminated glass.

[0012] Furthermore, the mass ratio of p-hydroxystyrene to 4-(chlorocarbonyl)benzoic acid is 7.1-10.7:10.9-16.4.

[0013] Furthermore, the mass ratio of the ultraviolet absorber to methyl 3-hydroxynonanoate is 12.7-19.0:8.9-13.4.

[0014] Furthermore, the mass ratio of the plasticizer precursor to 3-aminopropyltriethoxysilane is 16.7-25:8.4-12.6.

[0015] Furthermore, the mass ratio of modified plasticizer to polyvinyl butyral resin is 20-30:100-110.

[0016] Furthermore, the melt extrusion temperature is 130-180℃.

[0017] Furthermore, the pre-compression is carried out for 10-30 minutes at a temperature of 80-110℃ and a pressure of 0.6-1.2 MPa.

[0018] Furthermore, the hot pressing is carried out at a temperature of 135-145℃ and a pressure of 1.0-1.5 MPa for 90-180 minutes.

[0019] A heat-strengthened laminated glass is prepared by any of the above steps.

[0020] The beneficial effects of this invention are:

[0021] 1) This invention first involves a nucleophilic acyl substitution reaction between 4-(chlorocarbonyl)benzoic acid and p-hydroxystyrene, followed by a Friedel-Crafts rearrangement to obtain an ultraviolet absorber with an o-hydroxybenzophenone structure. Then, the obtained ultraviolet absorber is esterified with methyl 3-hydroxynonanoate to obtain a plasticizer precursor. Next, the plasticizer precursor is combined with 3-aminopropyltriethoxysilane via a Michael addition reaction between the double bond and the amino group to obtain a modified plasticizer. Finally, the modified plasticizer is co-extruded with polyvinyl butyral resin, calendered into a film, and laminated with a heat-strengthened glass sheet to obtain a high-performance heat-strengthened laminated glass.

[0022] 2) This invention constructs an o-hydroxybenzophenone structure, which can absorb ultraviolet light, significantly reducing the aging damage of ultraviolet light to the substrate, and reducing yellowing, embrittlement and performance degradation of the material. At the same time, the ultraviolet absorbing group is connected to the methyl 3-hydroxynonanoate plasticizer skeleton through the ester group. The ester group regulates the electron cloud density of the ultraviolet absorbing group through the electron-withdrawing effect, significantly broadening its ultraviolet absorption band and further enhancing the material's anti-ultraviolet performance. Moreover, the integrated structure of plasticizing and anti-ultraviolet is solved by solving the problem of easy migration of traditional ultraviolet absorbers, ensuring that the laminated glass maintains stable anti-ultraviolet performance during long-term use.

[0023] 3) The siloxane structure introduced in this invention, combined with the affinity between the long-chain alkyl groups in the methyl nonanoate backbone and the hydrophobic groups of PVB resin, improves the compatibility of the modified plasticizer with PVB resin, avoiding problems such as separation and precipitation, and ensuring that the interlayer maintains excellent optical clarity and surface smoothness. At the same time, the siloxane structure can enhance the interaction between the molecular chain and the hydroxyl groups on the glass surface, significantly enhancing the bonding strength between the PVB interlayer and the glass, meeting the impact resistance and penetration resistance requirements of heat-strengthened laminated glass, and achieving synergistic optimization of the overall material performance. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0026] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0027] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0028] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0029] The room temperature was 25±5℃.

[0030] Example 1

[0031] A method for preparing heat-strengthened laminated glass includes the following steps:

[0032] Step 1: By mass, 7.1 parts of p-hydroxystyrene, 10.9 parts of 4-(chlorocarbonyl)benzoic acid, and 60 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed, and the mixture was reacted at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into ice water, and the pH was adjusted to 3 with dilute hydrochloric acid. The solid was then filtered to obtain a solid, which was washed with deionized water and dried. The obtained solid was then mixed with 14.3 parts of aluminum chloride and 40 parts of dichlorobenzene and reacted at 130°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and then concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution was poured into dichloromethane, and finally, the solvent was removed by rotary evaporation to obtain the ultraviolet absorber.

[0033] Step 2: By mass, 12.7 parts of ultraviolet absorber, 8.9 parts of methyl 3-hydroxynonanoate, 9.6 parts of p-toluenesulfonic acid, and 100 parts of N,N-dimethylformamide are mixed in a reaction vessel, stirred evenly, heated to 60°C and reacted for 4 hours. After the reaction is completed, the mixture is cooled to room temperature, and then the reaction solution is poured into ice water. The solid is filtered and washed successively with saturated sodium bicarbonate solution and deionized water, dried, and finally the solvent is removed by vacuum distillation to obtain the plasticizer precursor.

[0034] Third step: According to the mass fraction, 16.7 parts of plasticizer precursor, 8.4 parts of 3-aminopropyltriethoxysilane and 80 parts of toluene are mixed in a reaction vessel, stirred evenly and reacted at 55°C for 4 hours. After the reaction is completed, the mixture is cooled to room temperature and then the solvent is removed by rotary evaporation to obtain the modified plasticizer.

[0035] Step 4: According to the mass percentage, add 20 parts of modified plasticizer and 110 parts of polyvinyl butyral resin to a high-speed mixer and mix. Then add the mixture to a screw extruder and melt-extrude it at 130°C. Calender it into a film and cover it with the first heat-strengthened glass plate. Then cover it with the second heat-strengthened glass plate to obtain a laminated glass plate. Then pre-press the laminated glass plate, then hot-press it together and cool it to obtain heat-strengthened laminated glass.

[0036] The pre-compression is carried out at a temperature of 80℃ and a pressure of 0.6 MPa for 10 minutes; the hot-compression is carried out at a temperature of 135℃ and a pressure of 1.0 MPa for 90 minutes.

[0037] A heat-strengthened laminated glass is prepared by the above steps.

[0038] Example 2

[0039] A method for preparing heat-strengthened laminated glass includes the following steps:

[0040] Step 1: By mass, 10.7 parts of p-hydroxystyrene, 16.4 parts of 4-(chlorocarbonyl)benzoic acid, and 80 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed, and the mixture was reacted at room temperature for 3 hours. After the reaction was completed, the reaction solution was poured into ice water, and the pH was adjusted to 2 with dilute hydrochloric acid. The solid was then filtered to obtain a solid, which was washed with deionized water and dried. The obtained solid was then mixed with 25 parts of aluminum chloride and 70 parts of dichlorobenzene and reacted at 160°C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and then concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution was poured into dichloromethane, and finally, the solvent was removed by rotary evaporation to obtain the ultraviolet absorber.

[0041] Step 2: By mass, 19.0 parts of ultraviolet absorber, 13.4 parts of methyl 3-hydroxynonanoate, 20 parts of p-toluenesulfonic acid, and 110 parts of N,N-dimethylformamide are mixed in a reaction vessel, stirred evenly, heated to 50°C and reacted for 6 hours. After the reaction is completed, the mixture is cooled to room temperature, and then the reaction solution is poured into ice water. The solid is filtered and washed successively with saturated sodium bicarbonate solution and deionized water, dried, and finally the solvent is removed by vacuum distillation to obtain the plasticizer precursor.

[0042] Third step: According to the mass fraction, 25 parts of plasticizer precursor, 12.6 parts of 3-aminopropyltriethoxysilane and 100 parts of toluene are mixed in a reaction vessel, stirred evenly and reacted at 65°C for 6 hours. After the reaction is completed, the mixture is cooled to room temperature and then the solvent is removed by rotary evaporation to obtain the modified plasticizer.

[0043] Step 4: According to the mass percentage, add 30 parts of modified plasticizer and 100 parts of polyvinyl butyral resin to a high-speed mixer and mix. Then add the mixture to a screw extruder and melt-extrude at 180°C. Calender the mixture into a film and cover it with the first heat-strengthened glass plate. Then cover it with the second heat-strengthened glass plate to obtain a laminated glass plate. The laminated glass plate is then pre-pressed, hot-pressed and laminated, and cooled to obtain heat-strengthened laminated glass.

[0044] The pre-compression was carried out at a temperature of 95℃ and a pressure of 0.9 MPa for 20 minutes; the hot-compression was carried out at a temperature of 140℃ and a pressure of 1.2 MPa for 145 minutes.

[0045] A heat-strengthened laminated glass is prepared by the above steps.

[0046] Example 3

[0047] A method for preparing heat-strengthened laminated glass includes the following steps:

[0048] Step 1: By mass, 8 parts of p-hydroxystyrene, 12.3 parts of 4-(chlorocarbonyl)benzoic acid, and 65 parts of pyridine were mixed in a reaction vessel under ice-water bath conditions. After stirring evenly, the ice-water bath was removed, and the mixture was reacted at room temperature for 2.5 hours. After the reaction was completed, the reaction solution was poured into ice water, and the pH was adjusted to 2 with dilute hydrochloric acid. The solid was then filtered to obtain a solid, which was washed with deionized water and dried. The obtained solid was then mixed with 10.7 parts of aluminum chloride and 86 parts of dichlorobenzene and reacted at 145°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, and then concentrated by rotary evaporation to obtain a concentrated solution. The concentrated solution was poured into dichloromethane, and finally, the solvent was removed by rotary evaporation to obtain the ultraviolet absorber.

[0049] Step 2: By mass, 16 parts of ultraviolet absorber, 11.2 parts of methyl 3-hydroxynonanoate, 13.5 parts of p-toluenesulfonic acid, and 120 parts of N,N-dimethylformamide are mixed in a reaction vessel, stirred evenly, heated to 55°C and reacted for 5 hours. After the reaction is completed, the mixture is cooled to room temperature, and then the reaction solution is poured into ice water. The solid is filtered and washed successively with saturated sodium bicarbonate solution and deionized water, dried, and finally the solvent is removed by vacuum distillation to obtain the plasticizer precursor.

[0050] Third step: According to the mass fraction, mix 20 parts of plasticizer precursor, 10 parts of 3-aminopropyltriethoxysilane and 90 parts of toluene in a reaction vessel, stir evenly and react at 50°C for 4.5 hours. After the reaction is completed, cool to room temperature and then remove the solvent by rotary evaporation to obtain the modified plasticizer.

[0051] Step 4: According to the mass percentage, add 25 parts of modified plasticizer and 108 parts of polyvinyl butyral resin to a high-speed mixer and mix. Then add the mixture to a screw extruder and melt-extrude it at 150°C. Calender it into a film and cover it with the first heat-strengthened glass plate. Then cover it with the second heat-strengthened glass plate to obtain a laminated glass plate. Then pre-press the laminated glass plate, then hot-press it together and cool it to obtain heat-strengthened laminated glass.

[0052] The pre-compression was carried out at a temperature of 110℃ and a pressure of 1.2 MPa for 30 minutes; the hot-compression was carried out at a temperature of 145℃ and a pressure of 1.5 MPa for 180 minutes.

[0053] A heat-strengthened laminated glass is prepared by the above steps.

[0054] Comparative Example 1

[0055] By weight, 10 parts of triethylene glycol diisooctanoate, 10 parts of 2,4-dihydroxybenzophenone, 10 parts of γ-glycidyl etheroxypropyltrimethoxysilane, and 100 parts of polyvinyl butyral resin are added to a high-speed mixer and mixed. Then, the mixture is added to a screw extruder for melt extrusion, calendered into a film, and covered onto a first heat-strengthened glass plate. Subsequently, a second heat-strengthened glass plate is covered on top to obtain a laminated glass plate. The laminated glass plate is then pre-pressed, hot-pressed, and cooled to obtain heat-strengthened laminated glass.

[0056] The pre-compression is carried out at a temperature of 80℃ and a pressure of 0.6 MPa for 10 minutes; the hot-compression is carried out at a temperature of 135℃ and a pressure of 1.0 MPa for 90 minutes.

[0057] Experimental Example 1

[0058] The above embodiments and comparative examples were subjected to the following tests, and the test results are shown in Tables 1-2.

[0059] Referring to GB / T32020-2015 "Polyvinyl butyral Interlayer for Laminated Glass", the laminated glass samples and their interlayers were tested, and the test results are shown in Table 1. Referring to GB / T16422.3-2014 "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamp", the laminated glass samples were placed in a fluorescent ultraviolet aging chamber with a temperature of 60℃, a relative humidity of 60%, and an ultraviolet irradiation intensity of 0.8W / (m²·nm) for 1000h of continuous aging. The yellowing value and tensile strength retention rate after aging were then tested, and the test results are shown in Table 2.

[0060] Table 1

[0061] Tensile strength (MPa) Tensile strain at fracture (%) Knock value Example 1 24 380 9 Example 2 26 360 9 Example 3 25 370 9 Comparative Example 1 22 320 6

[0062] Table 2

[0063] Yellowing value after aging Tensile strength retention rate (%) Example 1 3.28 85 Example 2 3.06 88 Example 3 3.10 86 Comparative Example 1 3.85 82

[0064] As shown in Table 1, compared with Comparative Example 1, Examples 1-3 have lower yellowing values ​​and higher tensile strength, tensile strain at break, impact value, and light transmittance, indicating that the mechanical properties and UV resistance of Examples 1-3 are superior to those of Comparative Example 1, demonstrating the good compatibility between the modified plasticizer of the present invention and the PVB substrate. As shown in Table 2, the rate of change of yellowing values ​​of Examples 1-3 is less than that of the comparative example, and the retention rate of tensile strength is greater than that of the comparative example, indicating that the modified plasticizer of the present invention can effectively inhibit the yellowing of the intermediate film caused by ultraviolet radiation, and after long-term use, the optical properties are more stable and the mechanical properties decay more slowly, resulting in a longer service life.

[0065] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing heat-strengthened laminated glass, characterized in that, Includes the following steps: The first step involves esterifying p-hydroxystyrene with 4-(chlorocarbonyl)benzoic acid and then performing a Fourier rearrangement to obtain an ultraviolet absorber. The second step involves esterifying the ultraviolet absorber with methyl 3-hydroxynonanoate to obtain the plasticizer precursor. The third step involves an addition reaction between the plasticizer precursor and 3-aminopropyltriethoxysilane to obtain the modified plasticizer. Step 4: Modified plasticizer and polyvinyl butyral resin are blended, extruded, calendered into a film, and covered on the first heat-strengthened glass plate. Then, a second heat-strengthened glass plate is covered on top to obtain a laminated glass plate. The laminated glass plate is then pre-pressed, hot-pressed and bonded together, and cooled to obtain heat-strengthened laminated glass.

2. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The mass ratio of p-hydroxystyrene to 4-(chlorocarbonyl)benzoic acid mentioned in the first step is 7.1-10.7:10.9-16.

4.

3. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The mass ratio of the ultraviolet absorber and methyl 3-hydroxynonanoate mentioned in the second step is 12.7-19.0:8.9-13.

4.

4. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The mass ratio of the plasticizer precursor and 3-aminopropyltriethoxysilane mentioned in the third step is 16.7-25:8.4-12.

6.

5. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The mass ratio of the modified plasticizer and polyvinyl butyral resin mentioned in step four is 20-30:100-110.

6. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The reaction temperature described in the second step is 110-120℃.

7. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The pre-compression described in step four is carried out for 10-30 minutes at a temperature of 80-110℃ and a pressure of 0.6-1.2 MPa.

8. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The hot pressing described in step four is carried out at a temperature of 135-145℃ and a pressure of 1.0-1.5 MPa for 90-180 minutes.

9. The method for preparing a heat-strengthened laminated glass according to claim 1, characterized in that, The extrusion temperature described in step four is 130-180℃.

10. The heat-strengthened laminated glass obtained by the preparation method according to claim 1.