Anti-yellowing polyvinyl butyral resin as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to anti-yellowing polyvinyl butyral resin as well as a preparation method and application thereof. According to the invention, a specific ternary synergistic stable system is used as a main stable function source, a synergistic effect is generated through accurate molecular combination construction and proportion control, the problem of phenol yellowing is solved from the perspective of a reaction mechanism, on one hand, a traditional hindered phenol antioxidant is not used, and a main chemical source of yellowing is eliminated from the source; on the other hand, the defects that a non-phenol antioxidant system is poor in synergism and insufficient in environmental adaptability are overcome, the phenol yellowing phenomenon can be well inhibited, super-strong ultraviolet yellowing resistance, gas-induced yellowing resistance and damp-heat aging resistance are achieved, meanwhile, good compatibility with glass is ensured, and the service life of the glass is prolonged. And the paint has excellent long-term color stability and environmental adaptability and balanced comprehensive performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to an anti-yellowing polyvinyl butyral resin, its preparation method, and its application. Background Technology

[0002] Polyvinyl butyral (PVB) film, as the core material of laminated glass, has its long-term optical stability, especially its resistance to yellowing, as a key indicator of its quality. Traditional PVB films typically incorporate an antioxidant system primarily composed of hindered phenolic compounds (such as BASF's Irganox 1010) to achieve anti-aging properties.

[0003] However, hindered phenolic antioxidants have an inherent drawback: while they exert their chain-terminating effect, the benzene ring in their molecular structure is susceptible to oxidation by ultraviolet radiation and / or nitrogen oxides (NOx) in the air. x Under certain conditions, PVB will generate yellow or brown nitro / nitroso compounds such as quinone methylates through photo-oxidation reactions, causing irreversible "phenolic yellowing" or "gas fading" of PVB. This yellowing phenomenon is unacceptable in environments such as museums where absolute color fidelity is required.

[0004] Technicians have attempted to use non-phenolic antioxidant systems to avoid yellowing. For example, Chinese patent CN110128805A discloses the addition of phosphites and hindered amine light stabilizers (HALS) to PVB. However, its long-term UV aging resistance is insufficient; after 2000 hours of QUV aging, the yellowness index (YI) increment (ΔYI) typically exceeds 5.0. The literature "Polymer Degradation and Stability" reports the use of thioester antioxidants, but their effectiveness against gas-induced yellowing is limited. x After exposure, the increment (Δb) of the b-value in the CIE Lab chromaticity coordinates is greater than 3.0.

[0005] In conclusion, how to effectively solve the problem of phenolic yellowing of PVB is an urgent issue to be addressed in this field. Summary of the Invention

[0006] In view of this, the present invention provides an anti-yellowing PVB resin, its preparation method and application, and the anti-yellowing PVB resin provided by the present invention has excellent anti-yellowing properties.

[0007] This invention provides an anti-yellowing PVB resin, comprising the following components by weight: 100 parts of PVB resin, 0.3-1.2 parts of bisphenol A bisphosphate antioxidant, 0.2-0.8 parts of thiobisphenol antioxidant, 0.4-1.0 parts of NOR-HALS, 0.2-1.0 parts of ultraviolet absorber, 30-40 parts of plasticizer and 0.01-0.1 parts of alkaline earth metal fatty acid salt; the mass ratio of the bisphenol A bisphosphate antioxidant, thiobisphenol antioxidant and NOR-HALS is 100:(40-80):(50-100).

[0008] Preferably, the bisphenol A bisphosphate antioxidant is a phosphate compound having a bisphenol A skeleton, including one or more of bis(2,4-di-tert-butylphenyl pentaerythritol diphosphite), PEP-36 antioxidant, and BASF's Irgafos 168; the thiobisphenol antioxidant is an antioxidant containing two phenol structures linked by a thioether bond in the molecule; the thiobisphenol antioxidant includes one or more of 4,4'-thiobis(2-tert-butyl-5-methylphenol), 2,2'-thiobis(4-tert-octylphenol), and 1790 antioxidant; the NOR-HALS includes one or more of sebacic acid bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) ester and BASF's Tinuvin NOR 371.

[0009] Preferably, the anti-yellowing PVB resin does not contain hindered phenolic antioxidants.

[0010] Preferably, the anti-yellowing PVB resin further includes one or more of phosphite antioxidants and lactone antioxidants; the anti-yellowing PVB resin further includes a light stabilizer, which is one or more of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and BASF's Tinuvin 123.

[0011] Preferably, the total mass of the bisphenol A bisphosphate antioxidant, the thiobisphenol antioxidant, and NOR-HALS accounts for more than 90 wt% of the total mass of all antioxidants and light stabilizers.

[0012] This invention also provides a method for preparing the anti-yellowing PVB resin described above, comprising the following steps: The dried PVB resin is premixed with a plasticizer to obtain a premix. The premix is ​​then mixed with a bisphenol A bisphosphate antioxidant, a thiobisphenol antioxidant, NOR-HALS and an ultraviolet absorber to obtain a blend. The blend is then mixed with an alkaline earth metal fatty acid salt to obtain the anti-yellowing PVB resin.

[0013] The present invention also provides the application of the anti-yellowing PVB resin described in the above-described scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above-described scheme in laminated glass.

[0014] The present invention also provides a PVB film, the raw materials of which include the anti-yellowing PVB resin described in the above scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above scheme.

[0015] The present invention also provides a method for preparing the PVB film described above, comprising the following steps: The anti-yellowing PVB resin is calendered or cast into a sheet, wherein the anti-yellowing PVB resin is the anti-yellowing PVB resin described in the above scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above scheme, to obtain the PVB film.

[0016] The present invention also provides a color-fidelity laminated glass, comprising a PVB film and glass plates covering both sides of the PVB film; the PVB film is the PVB film described in the above-described scheme or the PVB film obtained by the preparation method described in the above-described scheme.

[0017] This invention provides an anti-yellowing PVB resin. This invention utilizes a specific ternary synergistic stabilizing system as the primary source of stabilizing function. Through precise molecular combination construction and ratio control, a synergistic effect is generated (synergistic effect index SEI>1.2). It addresses the phenolic yellowing problem from the perspective of reaction mechanism. On the one hand, it avoids the use of traditional hindered phenolic antioxidants, eliminating the main chemical origin of yellowing at its root. On the other hand, it overcomes the shortcomings of non-phenolic antioxidant systems, such as poor synergy and insufficient environmental adaptability. It can effectively inhibit phenolic yellowing, achieving superior resistance to UV yellowing, gas-induced yellowing, and damp heat aging. Simultaneously, it ensures good compatibility with glass (including Low-E glass), exhibiting excellent long-term color stability and environmental adaptability, resulting in a balanced overall performance.

[0018] Specifically, this invention creatively constructs a ternary synergistic stabilizing system composed of bisphenol A bisphosphate antioxidants, thiobisphenol antioxidants, and non-alkaline N-alkoxy hindered amine light stabilizers (NOR-HALS) in specific types and proportions. The functions and synergistic relationships of each component in the ternary synergistic stabilizing system are as follows: Bisphenol A bisphosphate antioxidants: As primary stabilizers, they block auto-oxidation chain reactions by efficiently decomposing hydroperoxides (ROOH). Their mechanism of action is non-free radical scavenging; both the bisphenol A itself and its decomposition products are colorless, fundamentally eliminating the possibility of phenolic substances transforming into quinone chromophores. Their specific bisphenol A backbone and phosphate ester structure provide good compatibility with PVB resins and moderate molecular migration.

[0019] Thiobisphenol antioxidants: As auxiliary stabilizers, their main function is to capture alkyl radicals (R·). Their molecular structure does not contain specific substituted phenolic units that easily form quinone structures, thus avoiding becoming a source of yellowing. Simultaneously, their thioether structure can synergistically interact with bisphenol A bisphosphate antioxidants, enhancing peroxide decomposition efficiency. The thiobisphenol antioxidants in this invention have a stable structure. Aging tests have verified that the release of volatile sulfur-containing compounds (specifically H2S, SO2, thiols, etc., which pose a potential corrosion risk to metals) is extremely low (<5ppm, determined by HS-GC-MS), meeting the compatibility requirements with the silver layer in Low-E glass.

[0020] NOR-HALS: As a long-lasting free radical scavenger, its N-alkoxy structure can generate stable nitryl radicals (>NO·) after capturing free radicals, and can be recycled. Its extremely low basicity avoids the formation of colored salts in the acidic environment of PVB, ensuring color stability. NOR-HALS mainly captures alkoxy radicals (RO·) and hydroxyl radicals (HO·), complementing thiobisphenol antioxidants.

[0021] The inventors' key discovery is that when bisphenol A bisphosphate antioxidants, thiobisphenol antioxidants, and NOR-HALS are used as the main sources of stabilizing function, and the mass ratio of bisphenol A bisphosphate antioxidants, thiobisphenol antioxidants, and NOR-HALS is 1:(0.4~0.8):(0.5~1.0), a significant synergistic effect (SEI>1.2) is generated among the three. The overall effect of resisting yellowing and inhibiting intrinsic resin degradation is far superior to the sum of any two or simple addition. Furthermore, the performance is stable under long-term thermo-oxidative, ultraviolet, and humid heat aging conditions, with no antagonistic effects. The components in the ternary synergistic stabilizing system cooperate to form a complementary and synergistic protection mechanism of "peroxide decomposition - free radical capture - long-term regeneration," and none of the components possess the structural basis for generating yellowing products.

[0022] This invention also provides a method for preparing the anti-yellowing PVB resin described in the above-mentioned scheme. The preparation method provided by this invention is simple in steps, convenient in operation, and safe and stable.

[0023] The present invention also provides the application of the anti-yellowing PVB resin described in the above-described scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above-described scheme in laminated glass.

[0024] This invention also provides a PVB film. The PVB film provided by this invention has a ΔYI ≤ 2.5 after 3000 hours of QUV-B aging and a ΔYI ≤ 3.0 after 1500 hours of xenon lamp aging. It also exhibits a NO content of [missing value]. x Δb after exposure in atmosphere The PVB film provided by this invention exhibits a low viscosity (≤1.5), a low ΔYI (≤4.0) after damp heat aging with minimal haze change, high peel strength retention, and effective inhibition of intrinsic PVB resin degradation. It also has low sulfur volatiles and high application safety. This invention provides a PVB film suitable for laminated glass, especially for laminated glass requiring extreme color fidelity.

[0025] This invention also provides a method for preparing the PVB film described in the above-described scheme. The preparation method provided by this invention is cost-controllable, environmentally friendly, and suitable for industrial-scale production.

[0026] This invention also provides a color-fidelity laminated glass. The color-fidelity laminated glass provided by this invention is particularly suitable for applications with stringent requirements for color fidelity and long-term reliability, such as protective glass for museums and art galleries, high-end automotive glass, or building curtain walls.

[0027] Overall, compared with the prior art, the present invention has achieved the following beneficial effects: 1. Completely eliminates phenolic yellowing problem, with excellent color stability: Completely abandoning traditional hindered phenolic antioxidants, it adopts a ternary synergistic stabilizing system with significant synergistic effects as the main source of stability, eliminating the main chemical origin of yellowing at its root. The product exhibits extremely low ΔYI in various harsh aging tests including QUV, xenon lamp, NOx gas, and damp heat.

[0028] 2. Significant synergistic effect, excellent long-lasting effect and environmental adaptability: The ternary synergistic stabilizing system with a specific ratio produces a synergistic protective effect of "1+1+1>3". It not only has strong resistance to UV yellowing, but also exhibits excellent color and light transmission stability in humid and hot environments, and has strong comprehensive environmental adaptability.

[0029] 3. Inhibits intrinsic degradation and balances overall performance: The ternary synergistic stabilizing system can effectively delay the photo-oxidative degradation of PVB resin molecular chains (manifested as a low molecular weight decrease rate and carbonyl index), achieving super anti-yellowing while ensuring the good long-term adhesion, mechanical properties and light transmittance of PVB films.

[0030] 4. Safe and reliable: The total amount of sulfur-containing volatiles released by the thiobisphenol antioxidant during the aging process is extremely low (<5ppm), ensuring compatibility with sensitive materials such as Low-E glass and broadening the application range of the product.

[0031] 5. Simplified formulation and strong feasibility: The core protection system is constructed with three antioxidants and stabilizers, which simplifies the formulation and avoids the instability of complex formulations. Detailed Implementation

[0032] This invention provides an anti-yellowing PVB resin, comprising the following components by weight: 100 parts of PVB resin, 0.3-1.2 parts of bisphenol A bisphosphate antioxidant, 0.2-0.8 parts of thiobisphenol antioxidant, 0.4-1.0 parts of NOR-HALS, 0.2-1.0 parts of ultraviolet absorber, 30-40 parts of plasticizer and 0.01-0.1 parts of alkaline earth metal fatty acid salt; the mass ratio of the bisphenol A bisphosphate antioxidant, thiobisphenol antioxidant and NOR-HALS is 100:(40-80):(50-100).

[0033] The anti-yellowing PVB resin provided by this invention comprises 100 parts by weight of PVB resin. In this invention, the hydroxyl content of the PVB resin is preferably 18-24%, more preferably 19%, the butyral content is preferably 70-80%, more preferably 75%, and the number-average molecular weight is preferably 60,000-80,000, more preferably 70,000.

[0034] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention includes 0.3 to 1.2 parts of bisphenol A bisphosphate antioxidant, preferably 0.5 to 1 part, and more preferably 0.8 parts.

[0035] In this invention, the bisphenol A bisphosphate antioxidant is preferably a phosphate compound having a bisphenol A backbone, specifically preferably including one or more of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, PEP-36 antioxidant, and BASF's Irgafos 168.

[0036] In this invention, the phosphorus content (in mass fraction) of the bisphenol A bisphosphate antioxidant is preferably 10-15 wt%, more preferably 11-14 wt%, and even more preferably 12-13 wt%.

[0037] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention includes 0.2 to 0.8 parts of thiobisphenol antioxidant, preferably 0.4 to 0.6 parts, and more preferably 0.5 parts.

[0038] In this invention, the thiobisphenol antioxidant is preferably an antioxidant containing two phenolic structures (with alkylated hydroxyl groups) linked by a thioether bond in the molecule; more preferably, the thiobisphenol antioxidant includes one or more of 4,4'-thiobis(2-tert-butyl-5-methylphenol), 2,2'-thiobis(4-tert-octylphenol), and 1790 antioxidant. The thiobisphenol antioxidant of this invention releases less than 5 ppm of volatile sulfur-containing compounds (e.g., H2S, SO2, and thiols) from the anti-yellowing PVB resin after 3000 hours of QUV-B aging (determined by headspace gas chromatography-mass spectrometry, conditions: sample 0.5 g, equilibration temperature 120 °C, equilibration time 60 min).

[0039] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention comprises 0.4 to 1.0 parts of NOR-HALS, preferably 0.6 to 0.8 parts, and more preferably 0.7 parts.

[0040] In this invention, the NOR-HALS preferably includes one or more of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and BASF's Tinuvin NOR 371.

[0041] In this invention, the alkalinity of the NOR-HALS is preferably less than 5.0 mg KOH / g (measured according to ASTM D2074 standard).

[0042] In this invention, the mass ratio of the bisphenol A bisphosphate antioxidant, the thiobisphenol antioxidant, and NOR-HALS is preferably 100:(50~70):(60~90), more preferably 100:60:(70~80), and even more preferably 100:60:75.

[0043] This invention does not require specific commercial brands of the bisphenol A bisphosphate antioxidants, thiobisphenol antioxidants, and NOR-HALS. Any product containing the above antioxidants or light stabilizers, or any compound whose key parameters (such as phosphorus content or alkalinity) are within the above range, can be used to achieve the purpose of this invention, as verified by conventional experiments in the art.

[0044] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention includes 0.2 to 1.0 parts of ultraviolet absorber, preferably 0.4 to 0.8 parts, and more preferably 0.6 parts.

[0045] In this invention, the ultraviolet absorber preferably includes one or more of benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers; the benzotriazole ultraviolet absorber preferably includes one or more of Tinuvin 326 and Tinuvin 328.

[0046] In this invention, the ultraviolet absorber preferably further includes one or more of BASF Tinuvin 1577 ED and BASF Tinuvin 405; the mass ratio of the PVB resin to BASF Tinuvin 1577 ED is preferably 100:0.1~0.3, more preferably 100:0.2; the mass ratio of the PVB resin to BASF Tinuvin 405 is preferably 100:0.05~0.2, more preferably 100:0.1~0.15. BASF Tinuvin 1577 ED can provide supplementary absorption for different ultraviolet bands, forming broadband protection with other ultraviolet absorbers. BASF Tinuvin 405 has a large molecular weight, is resistant to migration, and can provide highly efficient ultraviolet shielding, especially suitable for thick products or long-term weather resistance requirements.

[0047] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention includes 30-40 parts of plasticizer, preferably 32-38 parts, and more preferably 34-36 parts.

[0048] In this invention, the plasticizer preferably includes one or more of triethylene glycol di-2-ethylhexanoate (3GO) and diethylene glycol dibenzoate.

[0049] Based on the mass fraction of the PVB resin, the anti-yellowing PVB resin provided by the present invention comprises 0.01 to 0.1 parts of alkaline earth metal fatty acid salt, preferably 0.03 to 0.08 parts, and more preferably 0.05 parts.

[0050] In this invention, the alkaline earth metal fatty acid salt preferably includes one or more of zinc stearate and calcium stearate.

[0051] In this invention, the anti-yellowing PVB resin does not contain hindered phenolic antioxidants, and preferably includes (2,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0052] In this invention, the anti-yellowing PVB resin preferably further includes one or more of phosphite antioxidants and lactone antioxidants; the mass ratio of the PVB resin to the phosphite antioxidant is preferably 100:0.05~0.15, more preferably 100:0.1; the phosphite antioxidant is preferably BASF's Irgafos 38; the lactone antioxidant is preferably BASF's HP-136. Phosphite antioxidants, as auxiliary peroxide decomposition agents, have a similar mechanism to bisphenol A bisphosphite antioxidants but a different structure, and can further improve processing thermal stability. Attention should be paid to their hydrolytic stability during use.

[0053] In this invention, the anti-yellowing PVB resin preferably further includes a light stabilizer, which is one or more of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and BASF's Tinuvin 123.

[0054] In this invention, the total mass of the bisphenol A bisphosphate antioxidant, the thiobisphenol antioxidant, and NOR-HALS preferably accounts for more than 90 wt% of the total mass of all antioxidants and light stabilizers, more preferably 92-98 wt%, and even more preferably 95 wt%.

[0055] In this invention, "antioxidants and light stabilizers" specifically refer to additives whose main function is to inhibit polymer oxidative degradation or photodegradation, excluding additives that only have auxiliary stabilizing effects (such as multifunctional plasticizers, dyes or fillers).

[0056] This invention also provides a method for preparing the anti-yellowing PVB resin described above, comprising the following steps: The dried PVB resin is premixed with a plasticizer to obtain a premix. The premix is ​​then mixed with a bisphenol A bisphosphate antioxidant, a thiobisphenol antioxidant, NOR-HALS and an ultraviolet absorber to obtain a blend. The blend is then mixed with an alkaline earth metal fatty acid salt to obtain the anti-yellowing PVB resin.

[0057] This invention involves premixing dried PVB resin with a plasticizer to obtain a premix. In this invention, the drying temperature is preferably 100~120℃, more preferably 110℃, and the holding time is preferably based on the moisture content of the PVB resin being ≤0.1wt%, specifically 4 hours. The drying is preferably vacuum drying; the vacuum degree of the vacuum drying is preferably -0.097~-0.094MPa, more preferably -0.095MPa.

[0058] In this invention, the premixing equipment preferably includes a high-speed mixer; the premixing temperature is preferably room temperature (15~35 degrees Celsius), and the premixing time is preferably more than 2 minutes.

[0059] After obtaining the premix, the present invention mixes the premix with bisphenol A bisphosphate antioxidant, thiobisphenol antioxidant, NOR-HALS and ultraviolet absorber (denoted as the first mixture) to obtain a blend. In the present invention, the first mixture is preferably stirred; the shear rate of the stirred mixture is preferably 300~500s. -1 More preferably 350~450s -1 The temperature of the first mixing is preferably 90~110℃, more preferably 100℃, and the mixing time is preferably 10~20 minutes, more preferably 15 minutes.

[0060] After obtaining the blend, the present invention mixes the blend with an alkaline earth metal fatty acid salt (denoted as the second mixture) and sequentially performs melt extrusion and granulation to obtain the anti-yellowing PVB resin. In the present invention, the method and parameters of the second mixture are preferably the same as those of the first mixture, except that the mixing time is preferably more than 5 minutes.

[0061] In this invention, the melt extrusion equipment preferably includes a twin-screw extruder; the length-to-diameter ratio (L / D) of the twin-screw extruder is preferably 40 (medium shear screw combination); the barrel temperature of the twin-screw extruder is preferably 130~155℃, more preferably 135~155℃, specifically including four zones distributed sequentially: zone one, zone two, zone three, and zone four, wherein the temperature of zone one is 130℃, the temperature of zone two is 145℃, the temperature of zone three is 150℃, and the temperature of zone four is 148℃; the vacuum degree of the melt extrusion is preferably -0.09~-0.08MPa.

[0062] In this invention, the granulation is preferably water-cooled pelletizing.

[0063] The present invention also provides the application of the anti-yellowing PVB resin described in the above-described scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above-described scheme in laminated glass.

[0064] The present invention also provides a PVB film, the raw materials of which include the anti-yellowing PVB resin described in the above scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above scheme.

[0065] In this invention, the thickness of the PVB film is preferably 0.7~0.8 mm, more preferably 0.76 mm.

[0066] The PVB film provided by this invention meets the following performance requirements: (1) After 3000 hours of accelerated aging with QUV-B according to ISO 4892-2 standard, ΔYI≤2.5, the number average molecular weight decrease rate does not exceed 20%, and the carbonyl index does not exceed 0.25; (2) Xenon lamp aging for 1500 hours according to ISO 4892-2 standard (0.55W / m) 2 After (at 340nm, blackboard temperature 65℃, chamber temperature 50℃, relative humidity 50%, no dark cycle), ΔYI≤3.0; (3) At 80℃, containing 5 ppm NO x After exposure to the atmosphere for 168 hours, Δb in the CIE Lab chromaticity coordinates was ≤1.5; (4) After being treated at 85°C / 85% relative humidity for 1000 hours, ΔYI≤4.0, haze increase≤2.0%, and the peel strength retention rate with glass is not less than 75%.

[0067] The present invention also provides a method for preparing the PVB film described above, comprising the following steps: The anti-yellowing PVB resin is calendered or cast into a sheet, wherein the anti-yellowing PVB resin is the anti-yellowing PVB resin described in the above scheme or the anti-yellowing PVB resin obtained by the preparation method described in the above scheme, to obtain the PVB film.

[0068] In this invention, the calendering equipment preferably includes a calendering machine; the calendering temperature is preferably 125~130℃, more preferably 125℃.

[0069] In this invention, the casting equipment preferably includes a casting machine; the casting parameters include: a barrel temperature preferably of 130~150℃, more preferably 140℃; a die temperature preferably of 135~145℃, more preferably 140℃; a casting roller temperature preferably of 20~40℃, more preferably 30℃; a production line speed preferably of 2~10m / min, more preferably 5~8m / min; and a casting thickness adjusted according to actual needs, preferably 0.3~2.0mm, more preferably 1~1.5mm. The cooling method is preferably cooling roller cooling, specifically multi-stage cooling roller cooling. This invention, through the above casting method, obtains PVB films with a smooth surface, uniform thickness, and no bubbles.

[0070] The present invention also provides a color-fidelity laminated glass, comprising a PVB film and glass plates covering both sides of the PVB film; the PVB film is the PVB film described in the above-described scheme or the PVB film obtained by the preparation method described in the above-described scheme.

[0071] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments thereof.

[0072] In the specific embodiments and comparative examples of the present invention, the raw materials used are as follows: PVB resin: Commercial grade, hydroxyl content 19%, butyral content 75%, number average molecular weight 70,000; Plasticizer: 3GO; Bisphenol A bisphosphate antioxidant (referred to as component A in Table 1): bis(2,4-di-tert-butylphenyl pentaerythritol diphosphite, phosphorus content 10-15 wt%); Thiobisphenol antioxidant (referred to as component B in Table 1): BASF's Irganox 1035, chemical name: 2,2'-thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; NOR-HALS (denoted as component C in Table 1): BASF's Tinuvin NOR 371; UV absorber: Tinuvin 326; Alkaline earth metal fatty acid salts: BASF's Licolub Zn 2 (zinc stearate, CAS No.: 557-05-1); Traditional hindered phenolic antioxidant: BASF's Irganox 1010, CAS No.: 6683-19-8.

[0073] Examples and comparative examples: The formulations (parts by weight) of Examples 1-4 and Comparative Examples 1-5 of this invention are shown in Table 1: Table 1. Formulations of Examples 1-4 and Comparative Examples 1-5:

[0074] Note: Example 4 is a cost optimization example, achieved by fine-tuning the raw material ratio. Comparative Example 5 shows an imbalance in the raw material ratio.

[0075] The specific preparation method is as follows: The PVB resin was dried at 110℃ and -0.095 MPa vacuum for 4 hours until the moisture content was ≤0.1%. The dried PVB resin and plasticizer were added to a high-speed mixer and premixed at room temperature for 2 minutes. Components A, B, C, and the UV absorber were added sequentially. The high-speed mixer was heated to 95℃ and the speed was adjusted to 400 rpm (corresponding to a shear rate of 350 s). -1 Mix for 15 minutes until homogeneous. Finally, add zinc stearate and mix for 5 minutes. Feed the blend into a twin-screw extruder (L / D 40, medium shear screw combination), with the temperatures set at 130℃, 145℃, 150℃, and 148℃ (die temperature). Melt extrusion is performed under a vacuum of -0.08MPa, followed by water cooling and pelletizing. The pellets are calendered at 125℃ to obtain PVB sheets with a thickness of 0.76mm.

[0076] Performance Tests and Results: 1) Aging test: QUV-B aging: According to ISO 4892-2, aging for 3000 hours.

[0077] Xenon lamp aging: According to Method A in ISO 4892-2, cycle 1, aging for 1500 hours.

[0078] NOx Yellowing caused by gases: 80℃, 5ppm NO x The test lasted 168 hours.

[0079] Humid heat aging: Aging for 1000 hours at 85°C / 85%RH relative humidity.

[0080] 2) Intrinsic aging and compatibility characterization: GPC-measured molecular weight (M) n ) Rate of change.

[0081] FTIR measurement of carbonyl index (1710 cm⁻¹) -1 / Reference peak).

[0082] The total amount of volatile sulfur compounds (H2S, SO2, and thiols) after aging was determined by headspace gas chromatography-mass spectrometry (HS-GC-MS). Conditions: 0.5 g sample, equilibration temperature 120 °C, equilibration time 60 min.

[0083] The initial and post-wet-heat aging peel strengths of PVB film against ordinary float glass and sputtered Low-E glass were tested according to EN ISO 15184. The results of the above performance tests are shown in Table 2.

[0084] Table 2 Summary of performance test results:

[0085] Note: The peel strength data format is "float glass / Low-E glass"; Example 4 is a cost-optimized example, with a QUV ΔYI of 2.4, which meets the requirement of ≤2.5.

[0086] As shown in Table 2, Examples 1-4 exhibited excellent anti-yellowing capabilities in various aging tests, demonstrating comprehensive anti-yellowing performance. Comparative Example 1 (traditional phenolic system) showed the most severe yellowing problem. Comparative Examples 2, 3, and 4 lacked components A, B, and C, respectively, resulting in a significant decrease in all their performance characteristics, proving that the synergy of the three components (components A, B, and C) is a necessary condition for producing the best effect. The performance of Comparative Example 5 (imbalanced ratio) was also worse than that of Examples 1-4, indicating that a specific ratio is key to generating a synergistic effect. Based on the data from Examples 1 and Comparative Examples 2-4, the synergistic effect index (SEI) was as high as 1.25, proving that there is a significant synergistic effect among the three components, rather than a simple sum, highlighting the necessity and significance of ternary synergy.

[0087] It exhibits excellent environmental adaptability: Examples 1-4 showed extremely low yellowing and haze increase after damp heat aging, and high peel strength retention (all >75%), demonstrating the long-term reliability of the ternary synergistic stable system under harsh environments.

[0088] Application safety: The sulfur-containing volatile release of Examples 1-4 is extremely low (<5 ppm), and the adhesion to Low-E glass is good both initially and after damp heat aging, verifying its application safety.

[0089] Cost controllable: Through fine-tuning, Example 4 achieved cost reduction while meeting all core performance requirements (QUV ΔYI≤2.5), demonstrating the commercial flexibility and practical value of the present invention.

[0090] As can be seen from the above embodiments, this invention successfully prepares PVB films with excellent anti-yellowing properties, superior environmental adaptability, and good application safety through a ternary synergistic stabilizing system composed of bisphenol A bisphosphate antioxidants, thiobisphenol antioxidants, and NOR-HALS in specific types and proportions. The ternary synergistic stabilizing system exhibits significant synergistic effects and comprehensive performance, providing a reliable solution for high-end laminated glass.

[0091] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A PVB resin with anti-yellowing properties, characterized in that, Based on parts by mass, it includes the following components: 100 parts of PVB resin, 0.3-1.2 parts of bisphenol A bisphosphate antioxidant, 0.2-0.8 parts of thiobisphenol antioxidant, 0.4-1.0 parts of NOR-HALS, 0.2-1.0 parts of ultraviolet absorber, 30-40 parts of plasticizer and 0.01-0.1 parts of alkaline earth metal fatty acid salt; The mass ratio of the bisphenol A bisphosphate antioxidant, the thiobisphenol antioxidant, and NOR-HALS is 100:(40~80):(50~100).

2. The anti-yellowing PVB resin according to claim 1, characterized in that, The bisphenol A bisphosphate antioxidants include one or more of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, PEP-36 antioxidant, and BASF's Irgafos 168. The thiobisphenol antioxidants include one or more of 4,4'-thiobis(2-tert-butyl-5-methylphenol), 2,2'-thiobis(4-tert-octylphenol), and 1790 antioxidant. The NOR-HALS include one or more of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and BASF's Tinuvin NOR 371.

3. The anti-yellowing PVB resin according to claim 1, characterized in that, The anti-yellowing PVB resin does not contain hindered phenolic antioxidants.

4. The anti-yellowing PVB resin according to claim 1, characterized in that, The anti-yellowing PVB resin also includes one or more of phosphite antioxidants and lactone antioxidants; The anti-yellowing PVB resin also includes a light stabilizer, which is one or more of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and BASF's Tinuvin 123.

5. The anti-yellowing PVB resin according to claim 1, characterized in that, The total mass of the bisphenol A bisphosphate antioxidant, the thiobisphenol antioxidant, and NOR-HALS accounts for more than 90 wt% of the total mass of all antioxidants and light stabilizers.

6. The method for preparing the anti-yellowing PVB resin according to any one of claims 1 to 5, characterized in that, Includes the following steps: The dried PVB resin is premixed with a plasticizer to obtain a premix. The premix is ​​then mixed with a bisphenol A bisphosphate antioxidant, a thiobisphenol antioxidant, NOR-HALS and an ultraviolet absorber to obtain a blend. The blend is then mixed with an alkaline earth metal fatty acid salt to obtain the anti-yellowing PVB resin.

7. The application of the anti-yellowing PVB resin according to any one of claims 1 to 5 or the anti-yellowing PVB resin obtained by the preparation method according to claim 6 in laminated glass.

8. A PVB film, characterized in that, The raw materials include the anti-yellowing PVB resin according to any one of claims 1 to 5 or the anti-yellowing PVB resin obtained by the preparation method according to claim 6.

9. The method for preparing the PVB film according to claim 8, characterized in that, Includes the following steps: The anti-yellowing PVB resin is calendered or cast into a sheet, wherein the anti-yellowing PVB resin is the anti-yellowing PVB resin according to any one of claims 1 to 5 or the anti-yellowing PVB resin obtained by the preparation method according to claim 6, to obtain the PVB film.

10. A color-fidelity laminated glass, characterized in that, It includes a PVB film and glass plates covering both sides of the PVB film; the PVB film is the PVB film of claim 8 or the PVB film obtained by the preparation method of claim 9.

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