PVB-PU laminated material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polymer laminated materials, in particular to a PVB-PU laminated material as well as a preparation method and application thereof. The method comprises the following steps: carrying out low-temperature plasma treatment on a PVB (Polyvinyl Butyral) sheet to obtain an activated PVB sheet of which the surface is rich in active oxygen-containing groups; the preparation method comprises the following steps: mixing amino modified polyether polyol, diisocyanate, a composite cross-linking agent (glyceryl formal and pentaerythritol triacrylate) and a catalyst to obtain a PU composite system; and coating the surface of the activated PVB sheet with the PU composite system, and carrying out curing treatment to obtain the PVB-PU laminated material. The PVB surface is subjected to low-temperature plasma activation, a PU composite system formed by combining amino-modified polyether polyol and the composite cross-linking agent is adopted, chemical-physical synergistic high-strength interface bonding is achieved under the low isocyanate group / hydroxyl proportion, and meanwhile the weather resistance, the optical performance and the process stability of the material are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of polymer laminate technology, and in particular to a PVB-PU laminate material, its preparation method, and its application. Background Technology

[0002] Polyvinyl butyral (PVB) is widely used as the interlayer material in laminated safety glass due to its excellent impact toughness, light transmittance, and adhesion to glass. To improve the wear resistance and weather resistance of the PVB layer, a polyurethane (PU) layer is often laminated onto its surface. Currently, the lamination of PVB and PU mainly relies on the chemical reaction between the hydroxyl groups (-OH) on the PVB molecular chain and the isocyanate groups (-NCO) in the PU prepolymer to form chemical bonds and achieve interfacial adhesion.

[0003] However, this bonding method, which relies on reactions of specific functional groups, has significant drawbacks. First, to ensure sufficient reaction and the formation of adequate adhesive force, an excessive amount of isocyanate groups must be used, typically requiring strict control of the isocyanate-to-hydroxyl equivalence ratio (-NCO / -OH) at a high level (e.g., 1.01:1 to 1.5:1). This places extremely high demands on the precision of raw material metering and process control, resulting in poor process tolerance, difficulty in ensuring production stability, and the high free isocyanate content may also bring other problems. Second, this technical route heavily relies on specific crosslinking agents (such as the small molecule polyol trimethylolpropane) and specific curing methods (such as UV curing) that match this highly reactive system, greatly limiting the selection of raw materials and the flexibility of the process. More importantly, interfaces relying solely on chemical bonding are prone to bond breakage or aging under long-term exposure to environmental stresses such as humidity, heat, and UV light, leading to significant attenuation of interfacial adhesive strength, yellowing of materials, and other problems, affecting the service life and reliability of laminated products.

[0004] Therefore, there is an urgent need in this field for a new PVB-PU interface construction strategy that can break away from the dependence on a single, highly active chemical bonding mechanism, thereby broadening the process window, reducing the constraints on specific raw materials, and ultimately obtaining laminated materials with stronger adhesion and better weather resistance. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a PVB-PU laminate material, its preparation method, and its application. By activating the PVB surface with low-temperature plasma and using a PU composite system combining amino-modified polyether polyol with a composite crosslinking agent, a high-strength interfacial bond with "chemical-physical" synergy is achieved at a low isocyanate group / hydroxyl ratio, while significantly improving the material's weather resistance, optical properties, and process stability.

[0006] To achieve the above objectives, the present invention provides a method for preparing a PVB-PU laminate material, comprising the following steps: S1. PVB sheets are subjected to low-temperature plasma treatment to obtain activated PVB sheets with active oxygen-containing groups on the surface; S2. Mix amino-modified polyether polyol, diisocyanate, composite crosslinking agent, and catalyst to obtain a PU composite system; the composite crosslinking agent includes glycerol formaldehyde and pentaerythritol triacrylate; S3. Coat the surface of the activated PVB sheet with the PU composite system and cure it to obtain the PVB-PU laminate material.

[0007] Preferably, in S1, the PVB sheet is a plasticized PVB sheet; the preparation method of the plasticized PVB sheet includes the following steps: mixing PVB resin and plasticizer at a mass ratio of 100:(25-45), and extruding to obtain the plasticized PVB sheet; the plasticizer is selected from at least one of diisooctyl oleate and dibutyl sebacate.

[0008] Preferably, in S1, the power of the low-temperature plasma treatment is 30-80W, and the time is 10-60s.

[0009] Preferably, in S2, the number average molecular weight of the amino-modified polyether polyol is 1000-5000, and the amino content is 0.5-2.0 wt%; in the PU composite system, the equivalent ratio of isocyanate groups to hydroxyl groups is (0.8-1.0):1.

[0010] Preferably, in S2, the diisocyanate is selected from at least one of isophorone diisocyanate and hexamethylene diisocyanate; the mass ratio of glycerol formaldehyde and pentaerythritol triacrylate is 1:(2-3).

[0011] Preferably, in S2, the catalyst comprises stannous octoate and triethylenediamine, wherein the mass ratio of stannous octoate to triethylenediamine is 1:(1-2); and in the PU composite system, the mass fraction of the catalyst is 0.1-0.5%.

[0012] Preferably, in S2, the PU composite system further includes functional additives; the functional additives include ultraviolet absorbers and antioxidants; the ultraviolet absorber is selected from 2-hydroxy-4-methoxybenzophenone; the antioxidant is selected from antioxidant 1010.

[0013] Preferably, in S3, the coating thickness is 76-254 μm; the curing process is gradient curing, including: pre-curing at 40-60℃ for 30-60 min, and then final curing at 80-90℃ for 60-90 min.

[0014] The present invention also provides a PVB-PU laminate material, which is prepared according to the preparation method described above.

[0015] This invention provides the application of the aforementioned PVB-PU laminate in automotive windshields, architectural laminated glass, or cut-resistant covers.

[0016] The beneficial effects of this invention are as follows: (1) This invention activates the PVB surface using low-temperature plasma, which not only introduces abundant active oxygen-containing groups but also forms a micron-scale rough structure. These active sites, together with the network rich in polar groups (such as urea bonds) formed after the reaction of amino-modified polyether polyols in the PU composite system, can generate a stronger synergistic effect of chemical bonding and physical anchoring. This innovative mechanism enables the invention to achieve excellent interfacial adhesion performance under conditions of a low isocyanate group to hydroxyl equivalent ratio. At the same time, the low and broad -NCO / -OH ratio requirement reduces the stringent dependence on the accuracy of raw material metering, broadens the process window, and improves production stability.

[0017] (2) The composite crosslinking agent (glycerol formaldehyde and pentaerythritol triacrylate) used in this invention, in conjunction with amino-modified polyether polyol, constructs a PU structure that combines moderate crosslinking density and good network toughness. With the addition of ultraviolet absorbers (such as UV-9) and antioxidants (such as 1010), the material's ability to resist degradation by heat, oxygen, and ultraviolet light is systematically enhanced.

[0018] (3) The PVB-PU laminate prepared by this invention achieves high strength and high weather resistance while maintaining excellent optical performance, with a light transmittance of over 91.5%. These balanced and excellent comprehensive properties enable it to meet the stringent requirements of optical clarity, safety and durability in applications such as automotive windshields and high-end architectural laminated glass.

[0019] (4) The low-temperature plasma surface treatment, PU system coating, and gradient temperature curing processes involved in the preparation method of this invention are all mature and controllable industrial technologies. The viscosity range of the PU composite system has been optimized, and it has good coating operability and leveling properties. The entire process does not require major modifications to the existing laminated glass production line, and it is easy to achieve large-scale and continuous production, with broad prospects for industrial application. Detailed Implementation

[0020] This invention provides a method for preparing a PVB-PU laminate, comprising the following steps: S1. PVB sheets are subjected to low-temperature plasma treatment to obtain activated PVB sheets with active oxygen-containing groups on the surface; S2. Mix amino-modified polyether polyol, diisocyanate, composite crosslinking agent, and catalyst to obtain a PU composite system; the composite crosslinking agent includes glycerol formaldehyde and pentaerythritol triacrylate; S3. Coat the surface of the activated PVB sheet with the PU composite system and cure it to obtain the PVB-PU laminate material.

[0021] In this invention, in S1, the PVB sheet is a plasticized PVB sheet; the preparation method of the plasticized PVB sheet includes the following steps: mixing PVB resin and plasticizer at a mass ratio of 100:(25-45), and extruding to obtain the plasticized PVB sheet; the plasticizer is selected from at least one of diisooctyl oleate (DOA) and dibutyl sebacate (DBS).

[0022] In this invention, the number-average molecular weight (M) of PVB resin is... n The content of hydroxyl groups is 17-25 wt%, with a range of 40,000-60,000.

[0023] In this invention, in S1, the power of the low-temperature plasma treatment is 30-80W, and the time is 10-60s.

[0024] In this invention, in step S1, low-temperature plasma is used to treat the surface of the PVB sheet. High-energy particles in the plasma bombard the PVB surface, breaking some CH and CC bonds, thereby introducing active oxygen-containing groups such as hydroxyl and carboxyl groups onto its surface, and simultaneously forming a certain micro-rough structure (surface roughness Rz is 100 × 10⁻⁶). -5 -150×10 -5 (Within cm). This treatment provides abundant chemically active sites for subsequent bonding with the PU layer, and also constructs a physical anchoring structure that enhances mechanical interlocking. It is important to note that the treatment parameters need to be precisely controlled according to the equipment and material characteristics to avoid over-treatment that could lead to PVB surface degradation and affect its bulk properties.

[0025] In this invention, in S2, the number-average molecular weight (M) of the amino-modified polyether polyol is... n The amino content is 0.5-2.0 wt% and the amino content is 1000-5000; the amino-modified polyether polyol is selected from at least one of amino-modified polytetrahydrofuran ether diol and amino-modified polypropylene glycol; in the PU composite system, the equivalent ratio of isocyanate groups to hydroxyl groups is (0.8-1.0):1.

[0026] In this invention, the preparation method of amino-modified polytetrahydrofuran ether diol (using a nucleophilic substitution reaction between hydroxyl-terminated polytetrahydrofuran ether diol and an amination reagent) includes the following steps: (1) Raw material preparation Hydroxyl-terminated polytetrahydrofuran ether diol (CAS No.: 25190-06-1): Number average molecular weight 1000-5000, hydroxyl value range 40-110 mgKOH / g; Amination reagent: ethylenediamine, hexamethylenediamine or diethanolamine; Catalyst: sodium hydroxide or potassium hydroxide; (2) Reaction Hydroxyl-terminated polytetrahydrofuran ether diol and an amination reagent were mixed at a molar ratio of 1:2-4. A catalyst (0.5-2.0 wt% of the total mass of the reaction system) was added, and the mixture was heated to 120-160℃ under nitrogen protection and maintained at this temperature for 4-8 hours. Water generated during the reaction was removed using a water separator. After the reaction, the temperature was lowered to ≤80℃, and the mixture was washed 2-3 times with an appropriate amount of deionized water to remove unreacted amination reagent and catalyst. Subsequently, vacuum distillation (vacuum ≤ -0.09 MPa, temperature 100-120℃) was performed to remove moisture, finally yielding amino-modified polytetrahydrofuran ether diol with an amino content of 0.5-2.0 wt%.

[0027] In this invention, the preparation method of amino-modified polypropylene glycol (using a stepwise polymerization reaction of hydroxyl-terminated polypropylene glycol and isocyanate-based amine compounds) includes the following steps: (1) Raw material preparation Hydroxyl-terminated polypropylene glycol (CAS No.: 25322-69-4): number average molecular weight of 1000-5000, hydroxyl value range of 40-110 mgKOH / g; isocyanate-based amine compound: prepared by reacting diisocyanate with diamine; the diisocyanate is selected from isophorone diisocyanate (IPDI) or hexamethylene diisocyanate (HDI); the diamine is selected from ethylenediamine or propylenediamine; wherein the molar ratio of diisocyanate to diamine is 1:(1-1.5); the reaction temperature is 80-100℃, and the time is 2-4h.

[0028] (2) Reaction Hydroxyl-terminated polypropylene glycol was added to a dry reaction vessel, and the temperature was raised to 60-80℃ under nitrogen protection. At this temperature, isocyanate-based amine compounds were slowly added dropwise (the molar ratio of hydroxyl-terminated polypropylene glycol to isocyanate-based amine compounds was 1:(1-1.5)). After the addition was complete, the temperature was raised to 80-100℃, and the reaction was maintained for 2-4 hours. During the reaction, the characteristic peak of -NCO (2270 cm⁻¹) in the system was monitored by infrared spectroscopy. -1 The disappearance of ) was used to determine the reaction endpoint. After the reaction was completed, the product was subjected to vacuum distillation at 90-110℃ and a vacuum degree ≤-0.09MPa to remove trace amounts of low-boiling substances, and finally amino-modified polypropylene glycol with an amino content of 0.5-2.0wt% was obtained.

[0029] In this invention, amino-modified polyether polyol is selected as the key component in S2. Firstly, the reactivity of the amino groups introduced into its molecule with isocyanate groups is far higher than that of the hydroxyl groups in traditional polyols. This allows the PU composite system to maintain rapid and sufficient curing and crosslinking reactions even with a relatively low overall isocyanate-to-hydroxyl equivalent ratio (0.8-1.0:1). Specifically, the amino groups react with isocyanates to form urea bonds, while the residual hydroxyl groups in the polyol and the hydroxyl groups on the PVB surface can also react with isocyanates to form urethane bonds, together constructing a stable PU crosslinking network. More importantly, the crosslinked PU network is rich in nitrogen-containing polar groups such as urea bonds and urethane bonds. These groups can form strong hydrogen bond interactions and even new chemical bonds with the active oxygen-containing groups such as hydroxyl and carboxyl groups introduced into the PVB surface through low-temperature plasma activation in S1. Furthermore, plasma treatment also forms a certain micro-roughness structure on the PVB surface (Rz=100×10⁻⁶). -5 -150×10 -5 (cm) provides a physical anchoring effect. Through the synergistic effect of "chemical bonding (double) + physical anchoring", a stronger and more stable bonding system is established at the interface between PVB and PU phases, thereby achieving excellent interlayer adhesion performance.

[0030] In this invention, in S2, the diisocyanate is selected from at least one of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI); the composite crosslinking agent includes glycerol formaldehyde (GF) and pentaerythritol triacrylate (PETA), and the mass ratio of glycerol formaldehyde to pentaerythritol triacrylate is 1:(2-3).

[0031] In this invention, S2 employs a composite crosslinking agent composed of glycerol formaldehyde and pentaerythritol triacrylate. The two substances work synergistically by utilizing their different functional group structures and reaction characteristics: glycerol formaldehyde helps introduce flexible segments into the crosslinking network, while the multifunctionality of pentaerythritol triacrylate provides dense crosslinking points. The combined use of these two substances allows the final PU network to achieve both good crosslinking reaction efficiency and excellent long-term network stability, which plays a crucial role in improving the overall mechanical properties, heat resistance, and aging resistance of the laminated material.

[0032] In this invention, in S2, the catalyst comprises stannous octoate (SnOct2) and triethylenediamine (TEDA), wherein the mass ratio of stannous octoate to triethylenediamine is 1:(1-2).

[0033] In this invention, in step S2, the PU composite system further includes functional additives; the functional additives include ultraviolet absorbers and antioxidants; the ultraviolet absorber is selected from 2-hydroxy-4-methoxybenzophenone (UV-9); the antioxidant is selected from antioxidant 1010.

[0034] In this invention, the ultraviolet absorber effectively absorbs and dissipates ultraviolet light energy, blocking the irradiation damage of ultraviolet light to the PVB-PU polymer chains, thereby delaying the photoaging process of the material; the antioxidant inhibits the oxidative degradation process of the material under thermo-oxidative conditions. The synergistic effect of both enhances the long-term weather resistance of the final PVB-PU laminate, delaying yellowing and performance degradation.

[0035] In this invention, in S2, the mixing is carried out by stirring at a speed of 500-1000 r / min for 15-30 min in a constant temperature environment of 20-30℃ until the system is homogeneous and transparent.

[0036] In this invention, in S2, the viscosity of the PU composite system is 300-800 cps (test temperature 25°C).

[0037] In this invention, in S3, the coating thickness is 76-254 μm; the curing process is gradient curing, including: pre-curing at 40-60℃ for 30-60 min, and then final curing at 80-90℃ for 60-90 min.

[0038] In this invention, step S3 employs a gradient curing process. First, pre-curing is performed at a lower temperature. This stage primarily promotes the full interfacial reaction between the PU composite system and the activated PVB surface, forming a preliminary stable bond. Subsequently, final curing is performed at a higher temperature to ensure complete cross-linking within the PU system, forming a dense and stable network structure. This gradient temperature curing strategy effectively avoids problems such as accelerated migration of plasticizers within the PVB layer and the formation of bubbles or micropores at the interface caused by direct high-temperature curing, thereby ensuring the integrity and optical uniformity of the laminated material interface.

[0039] The present invention also provides a PVB-PU laminate material, which is prepared according to the preparation method described above.

[0040] This invention provides the application of the aforementioned PVB-PU laminate in automotive windshields, architectural laminated glass, or cut-resistant covers.

[0041] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0042] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0043] In the comparative examples of the embodiments of the present invention, the relevant information of the raw materials used is as follows: (1) PVB resin: M n =50000, hydroxyl content is 20.5wt%, acetate content is 1.2wt%; (2) Amino-modified polyether polyols: Amino-modified polytetrahydrofuran ether diol (M n =2000, amino content is 1.0wt%), amino-modified polypropylene glycol (M n =3000, amino content is 1.5wt%). The preparation method of amino-modified polytetrahydrofuran ether diol includes the following steps: Raw material preparation: Hydroxyl-terminated polytetrahydrofuran ether diol: number average molecular weight of 2000, hydroxyl value range of 56.0-56.5 mgKOH / g; Amination reagent: ethylenediamine; Catalyst: potassium hydroxide.

[0044] Reaction: Hydroxyl-terminated polytetrahydrofuran ether diol and an amination reagent were mixed at a molar ratio of 1:3. A catalyst (1.0 wt% of the total mass of the reaction system) was added, and the mixture was heated to 140°C under nitrogen protection and maintained at this temperature for 6 hours. Water generated during the reaction was removed using a water separator. After the reaction, the temperature was lowered to 80°C, and the mixture was washed three times with an appropriate amount of deionized water to remove unreacted amination reagent and catalyst. Subsequently, vacuum distillation (vacuum degree -0.095 MPa, temperature 110°C) was performed to remove moisture, finally yielding amino-modified polytetrahydrofuran ether diol (M... n =2000, amino content is 1.0wt%.

[0045] The preparation method of amino-modified polypropylene glycol includes the following steps: Raw material preparation: Hydroxyl-terminated polypropylene glycol: number average molecular weight of 3000, hydroxyl value range of 37.2-37.8 mgKOH / g; Isocyanate-based amine compounds: prepared by reacting IPDI with ethylenediamine, with a molar ratio of 1:1, a reaction temperature of 90℃, and a reaction time of 3h.

[0046] Reaction: Hydroxyl-terminated polypropylene glycol was added to a dry reaction vessel, and the temperature was raised to 70°C under nitrogen protection. At this temperature, isocyanate-based amine compounds (the molar ratio of hydroxyl-terminated polypropylene glycol to isocyanate-based amine compounds was 1:1.2) were slowly added dropwise. After the addition was complete, the temperature was raised to 90°C, and the reaction was maintained at this temperature for 3 hours. During the reaction, the characteristic peak of -NCO (2270 cm⁻¹) in the system was monitored by infrared spectroscopy. -1 The disappearance of [a substance] was used to determine the reaction endpoint. After the reaction was completed, the product was subjected to vacuum distillation at 100℃ and a vacuum degree of -0.095MPa to remove trace amounts of low-boiling substances, finally yielding amino-modified polypropylene glycol (M). n =3000, amino content is 1.5wt%.

[0047] Example 1 This embodiment provides a method for preparing a PVB-PU laminate material, including the following steps: PVB resin and plasticizer (DOA) were mixed at a mass ratio of 100:35 and extruded to obtain a plasticized PVB sheet with a thickness of 762 micrometers. The plasticized PVB sheet was then placed in a low-temperature plasma treatment device, with argon gas introduced as the treatment gas, and treated at a power of 50W for 30 seconds. After treatment, activated PVB sheet was obtained, and a micro-rough structure (Rz = 120 × 10⁻⁶) was formed on the surface of the sheet. - 5 (cm), and is rich in active oxygen-containing groups such as hydroxyl and carboxyl groups.

[0048] 60 parts by weight of amino-modified polytetrahydrofuran ether diol, 25 parts by weight of diisocyanate (IPDI), 8 parts by weight of crosslinking agent (GF and PETA, mass ratio 1:2), 0.3 parts by weight of catalyst (SnOct2 and TEDA, mass ratio 1:1), 0.5 parts by weight of ultraviolet absorber (UV-9) and 0.3 parts by weight of antioxidant (antioxidant 1010) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 500 cps (25℃). The equivalent ratio of isocyanate groups to hydroxyl groups in the system was 0.9:1.

[0049] The PU composite system was coated onto the surface of activated PVB sheet with a coating thickness of 150 μm, followed by gradient curing treatment: first pre-curing at 50℃ for 45 min, and then final curing at 85℃ for 75 min; thus obtaining the PVB-PU laminate material.

[0050] Example 2 This embodiment provides a method for preparing a PVB-PU laminate material, including the following steps: PVB resin and plasticizer (DBS) were mixed at a mass ratio of 100:40 and extruded to obtain a plasticized PVB sheet with a thickness of 762 micrometers. The plasticized PVB sheet was then placed in a low-temperature plasma treatment device, with oxygen introduced as the treatment gas, and treated at a power of 60W for 20 seconds. After treatment, activated PVB sheets were obtained, and a micro-rough structure (Rz = 130 × 10⁻⁶) was formed on the sheet surface. - 5 (cm), and is rich in active oxygen-containing groups such as hydroxyl and carboxyl groups.

[0051] 55 parts by weight of amino-modified polypropylene glycol, 28 parts by weight of diisocyanate (HDI), 9.4 parts by weight of crosslinking agent (GF and PETA, mass ratio 1:3), 0.4 parts by weight of catalyst (SnOct2 and TEDA, mass ratio 1:2), 0.6 parts by weight of ultraviolet absorber (UV-9) and 0.4 parts by weight of antioxidant (antioxidant 1010) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 650 cps (25℃). The equivalent ratio of isocyanate groups to hydroxyl groups in the system was 1.0:1.

[0052] The PU composite system was coated onto the surface of activated PVB sheet with a coating thickness of 200 μm, followed by gradient curing: first pre-curing at 55℃ for 40 min, and then final curing at 88℃ for 80 min; thus obtaining the PVB-PU laminate material.

[0053] Example 3 This embodiment provides a method for preparing a PVB-PU laminate material, including the following steps: PVB resin and plasticizers (DOA and DBS, mass ratio 1:1) were mixed at a mass ratio of 100:32 and extruded to obtain a plasticized PVB sheet with a thickness of 762 micrometers. The plasticized PVB sheet was then placed in a low-temperature plasma treatment device, with argon and oxygen (volume ratio 1:1) as the treatment gases, and treated at a power of 40W for 40 seconds. After treatment, activated PVB sheets were obtained, with a micro-roughened structure (Rz = 110 × 10⁻⁶) formed on the sheet surface. -5 (cm), and is rich in active oxygen-containing groups such as hydroxyl and carboxyl groups.

[0054] 29 parts by weight of amino-modified polytetrahydrofuran ether glycol, 29 parts by weight of amino-modified polypropylene glycol, 9 parts by weight of diisocyanate (IPDI), 9 parts by weight of crosslinking agent (GF and PETA, mass ratio 1:2.5), 0.35 parts by weight of catalyst (SnOct2 and TEDA, mass ratio 1:1.5), 0.4 parts by weight of ultraviolet absorber (UV-9), and 0.3 parts by weight of antioxidant (antioxidant 1010) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 480 cps (25℃). The mass ratio of amino-modified polytetrahydrofuran ether glycol to amino-modified polypropylene glycol in the system was 1:1, and the equivalent ratio of isocyanate groups to hydroxyl groups was 0.85:1.

[0055] The PU composite system was coated onto the surface of activated PVB sheet with a coating thickness of 125 μm, followed by gradient curing treatment: first pre-curing at 45℃ for 50 min, and then final curing at 82℃ for 70 min; thus obtaining the PVB-PU laminate material.

[0056] Comparative Example 1 This comparative example provides a method for preparing a PVB-PU laminate material without activating the PVB, specifically including the following steps: Plasticized PVB sheets were prepared using the same method as in Example 1.

[0057] 60 parts by weight of amino-modified polytetrahydrofuran ether diol, 25 parts by weight of diisocyanate (IPDI), 8 parts by weight of crosslinking agent (GF and PETA, mass ratio 1:2), 0.3 parts by weight of catalyst (SnOct2 and TEDA, mass ratio 1:1), 0.5 parts by weight of ultraviolet absorber (UV-9) and 0.3 parts by weight of antioxidant (antioxidant 1010) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 500 cps (25℃). The equivalent ratio of isocyanate groups to hydroxyl groups in the system was 0.9:1.

[0058] The PU composite system was coated onto the surface of the plasticized PVB sheet with a coating thickness of 150 μm, and then subjected to gradient curing treatment: first pre-curing at 50℃ for 45 min, and then final curing at 85℃ for 75 min; thus obtaining the PVB-PU laminate material.

[0059] Comparative Example 2 This comparative example provides a method for preparing a PVB-PU laminate, which simulates traditional methods and specifically includes the following steps: Plasticized PVB sheets were prepared using the same method as in Example 1.

[0060] 60 parts by weight of amino-modified polytetrahydrofuran ether diol, 28 parts by weight of methylene bis(4-cyclohexyl isocyanate) (CAS No.: 5124-30-1), 8 parts by weight of crosslinking agent (trimethylolpropane), and 0.3 parts by weight of catalyst (dibutyltin dilaurate) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 600 cps (25℃). The equivalent ratio of isocyanate groups to hydroxyl groups in the system was 1.2:1.

[0061] The PU composite system was coated onto the surface of the plasticized PVB sheet with a coating thickness of 150 μm, and then cured: first by ultraviolet light curing (200 W / inch mercury lamp, irradiation speed 4.6 m / min), and then cured in an oven at 70℃ for 1 h; thus obtaining the PVB-PU laminate material.

[0062] Comparative Example 3 This comparative example provides a method for preparing a PVB-PU laminate material using a single crosslinking agent, specifically including the following steps: Activated PVB sheets were prepared using the same method as in Example 1.

[0063] 60 parts by weight of amino-modified polytetrahydrofuran ether diol, 25 parts by weight of diisocyanate (IPDI), 8 parts by weight of crosslinking agent (PETA), 0.3 parts by weight of catalyst (SnOct2 and TEDA, mass ratio 1:1), 0.5 parts by weight of ultraviolet absorber (UV-9), and 0.3 parts by weight of antioxidant (antioxidant 1010) were mixed and stirred at 750 r / min for 23 min at a constant temperature of 25℃ until the system was homogeneous and transparent, resulting in a PU composite system with a viscosity of 490 cps (25℃). The equivalent ratio of isocyanate groups to hydroxyl groups in the system was 0.9:1.

[0064] The PU composite system was coated onto the surface of activated PVB sheet with a coating thickness of 150 μm, followed by gradient curing treatment: first pre-curing at 50℃ for 45 min, and then final curing at 85℃ for 75 min; thus obtaining the PVB-PU laminate material.

[0065] Performance testing The PVB-PU laminates prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to comparative performance tests. The specific methods and standards for each test are as follows: Interfacial peel strength: tested according to ASTM D1876, rate 50 mm / min; Light transmittance: tested according to GB / T2680; Boiling water resistance: the sample was immersed in boiling water at 100℃ for 6 hours, removed, dried, and observed for delamination, and the peel strength was tested to calculate the retention rate; Weather resistance: a 1000-hour QUV aging test was conducted according to ASTM G154, and the yellowing index ΔYI was tested. The test results are recorded in Table 1.

[0066] Table 1 Test Results

[0067] As shown in Table 1, the PVB-PU laminates prepared in Examples 1-3 of this invention exhibit higher interfacial peel strengths (1.78-1.95 kN / m) than all comparative examples. In particular, compared to Comparative Example 1 (0.65 kN / m), which did not undergo surface activation and used a common polyol, the peel strength was significantly improved, fully demonstrating the crucial role of the synergistic effect of "PVB surface activation" and "amino-modified polyol" in enhancing interfacial adhesive strength. After undergoing boiling water and weathering tests, the sample samples from the examples showed high peel strength retention (≥94.3%) and low yellowing index (ΔYI≤0.85), exhibiting excellent environmental aging resistance. While Comparative Example 2 (simulating the traditional method) showed acceptable initial peel strength (1.30 kN / m), its aging resistance was poor (ΔYI=2.35, retention rate 78.5%), indicating that existing technologies relying on high NCO ratios and specific crosslinking agents have significant shortcomings in long-term durability. Comparative Example 3, which employed surface activation but used a single crosslinking agent, exhibited inferior performance compared to the example using a composite crosslinking agent. This demonstrates that the specific composite crosslinking agent employed in this invention is crucial for constructing a stable and durable PU network. Furthermore, all samples from the embodiments of this invention achieved light transmittance exceeding 91%, meeting the requirements for optical performance and surface hardness of the interlayer material in high-performance safety glass.

[0068] Therefore, this invention achieves high-strength interfacial bonding through low-temperature plasma activation of the PVB surface and the use of an amino-modified polyether polyol combined with a composite crosslinking agent to form a PU composite system, achieving a "chemical-physical" synergistic effect at a low isocyanate group / hydroxyl ratio, while significantly improving the material's weather resistance, optical properties and process stability.

[0069] Finally, it should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a PVB-PU laminate, characterized in that, Includes the following steps: S1. PVB sheets are subjected to low-temperature plasma treatment to obtain activated PVB sheets with active oxygen-containing groups on the surface; S2. Mix amino-modified polyether polyol, diisocyanate, composite crosslinking agent, and catalyst to obtain a PU composite system; the composite crosslinking agent includes glycerol formaldehyde and pentaerythritol triacrylate; S3. Coat the surface of the activated PVB sheet with the PU composite system and cure it to obtain the PVB-PU laminate material.

2. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S1, the PVB sheet is a plasticized PVB sheet; the preparation method of the plasticized PVB sheet includes the following steps: mixing PVB resin and plasticizer at a mass ratio of 100:(25-45), and extruding to obtain the plasticized PVB sheet; the plasticizer is selected from at least one of diisooctyl oleate and dibutyl sebacate.

3. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S1, the power of the low-temperature plasma treatment is 30-80W, and the time is 10-60s.

4. The method for preparing the PVB-PU laminate material according to claim 1, characterized in that, In S2, the number average molecular weight of the amino-modified polyether polyol is 1000-5000, and the amino content is 0.5-2.0 wt%; in the PU composite system, the equivalent ratio of isocyanate groups to hydroxyl groups is (0.8-1.0):

1.

5. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S2, the diisocyanate is selected from at least one of isophorone diisocyanate and hexamethylene diisocyanate; the mass ratio of glycerol formaldehyde and pentaerythritol triacrylate is 1:(2-3).

6. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S2, the catalyst comprises stannous octoate and triethylenediamine, wherein the mass ratio of stannous octoate to triethylenediamine is 1:(1-2); in the PU composite system, the mass fraction of the catalyst is 0.1-0.5%.

7. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S2, the PU composite system further includes functional additives; the functional additives include ultraviolet absorbers and antioxidants; the ultraviolet absorber is selected from 2-hydroxy-4-methoxybenzophenone; the antioxidant is selected from antioxidant 1010.

8. The method for preparing the PVB-PU laminate according to claim 1, characterized in that, In S3, the coating thickness is 76-254 μm; The curing process is a gradient curing process, which includes: first pre-curing at 40-60℃ for 30-60 minutes, and then final curing at 80-90℃ for 60-90 minutes.

9. A PVB-PU laminate material, characterized in that, Prepared by the method according to any one of claims 1 to 8.

10. The application of the PVB-PU laminate material according to claim 9 in automotive windshields, architectural laminated glass, or cut-resistant covers.

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