PVB (polyvinyl butyral) interlayer with local metallization pattern, preparation method of PVB interlayer and application of PVB interlayer in laminated glass

Abstract

The invention discloses a PVB (polyvinyl butyral) interlayer with a local metalized pattern, a preparation method of the PVB interlayer and application of the PVB interlayer in laminated glass. The PVB interlayer comprises a PVB base material layer and a local metalized pattern layer, the to-be-printed surface of the PVB base material layer is subjected to corona treatment or low-temperature plasma treatment, so that the surface energy of the to-be-printed surface is not lower than 42 mN / m; the local metallization pattern layer is formed by digital ink-jet printing, drying and curing of metal effect pigment printing ink on a preset area of the to-be-printed surface of the PVB base material layer; the metal effect pigment printing ink comprises a special effect metal pigment, the special effect metal pigment is a flaky pigment, the average particle size d50 of the special effect metal pigment is 0.5-5.0 [mu] m, and the maximum particle size D100 of the special effect metal pigment does not exceed 10 [mu] m. After the PVB interlayer is applied to the laminated glass, the laminated glass has aesthetic effects and functional characteristics and can be applied to the fields of buildings, automobiles, interior decoration and the like.

Description

A PVB interlayer with a locally metallized pattern, its preparation method, and its application in laminated glass. Technical Field

[0001] This invention relates to a PVB interlayer with a locally metallized pattern, its preparation method, and its application in laminated glass, belonging to the interdisciplinary field of polymer composite materials and digital printing technology. Background Technology

[0002] Laminated glass (also known as laminated glass) is a composite glass product made of two or more layers of glass sheets with one or more layers of tough polymer interlayer (most commonly PVB, or polyvinyl butyral) sandwiched in between, permanently bonded together through a high-temperature and high-pressure process. Due to its excellent safety, sound insulation, and heat insulation properties, laminated glass is widely used in building curtain walls, automotive windows, and interior decorative partitions.

[0003] To further enhance the aesthetic value and functional versatility of laminated glass, the industry often achieves customized effects by adding functional pigments to its core interlayer material—PVB interlayer. For example, Chinese patent CN106573447A discloses a polymer interlayer containing special effect metallic pigments. In this patent, special effect metallic pigments such as mica titanium and aluminum flakes are uniformly dispersed throughout the PVB interlayer through melt blending and extrusion processes, enabling the laminated glass to achieve an overall metallic appearance and reflective properties. However, this patent also has inherent limitations: 1) Design uniformity: The metallic pigment is evenly distributed throughout the entire interlayer, making it impossible to achieve complex customized patterns (such as corporate logos, QR codes), gradient colors, and other effects, resulting in extremely low design freedom; 2) Poor economic efficiency: To achieve local decoration or functional requirements, expensive metallic pigments need to be added to the entire PVB interlayer, resulting in low material utilization and significantly increased production costs; 3) Functional limitations: It is difficult to achieve a precise spatial distribution of "high light transmittance areas" and "high reflection / shading areas" on a single PVB interlayer, limiting its application in functional scenarios such as intelligent sunshade (such as partial sunshade of car sunroofs), display adaptation, and privacy protection.

[0004] Digital printing technology is a production technology that uses digital information (such as computer files) to directly control printing equipment and transfer colorants (inks) onto the substrate. It can print on various materials such as paper, plastic, fabric, glass, and metal. Therefore, digital printing technology provides a new direction for PVB sandwich patterning. However, when traditional flake metallic pigments (with an average particle size of 20-40 μm) used for extrusion are directly applied to digital inkjet printing, certain technical obstacles remain: pigment particles easily clog micron-sized inkjet printheads (nozzle diameter is typically 10-50 μm); large-particle-size pigments are difficult to disperse stably in the ink system. These technical obstacles have prevented the industrial application of this technology for a long time.

[0005] The performance of the polymer interlayer material in laminated glass has a significant impact on the overall performance of the laminated glass. While PVB resin has become the mainstream material for interlayers in laminated glass due to its excellent adhesion, transparency, flexibility, and sound insulation properties, its resistance to ultraviolet (UV) aging (weather resistance) is insufficient. Prolonged exposure to strong UV radiation causes the PVB polymer chains to degrade and yellow, leading to slight yellowing of the laminated glass after long-term use (especially at the edges), decreased light transmittance, and affecting its aesthetics and optical performance. To improve the UV aging resistance of PVB film materials, current methods mainly involve adding organic or inorganic UV absorbers. However, UV absorbers have limited effect on improving weather resistance, and improper addition can even impair the light transmittance of the PVB film. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a PVB interlayer with a locally metallized pattern, its preparation method, and its application in laminated glass.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a PVB interlayer with a locally metallized pattern, comprising a PVB substrate layer and a locally metallized pattern layer formed by digital inkjet printing; the PVB substrate layer is a transparent sheet, which is obtained by melt extrusion of PVB resin, plasticizer, antioxidant, UV stabilizer, light stabilizer, modified nano-silica, γ-glycidyl etheroxypropyltrimethoxysilane, polydopamine-modified bacterial cellulose, dispersant and defoamer, and the PVB resin meets the following parameters: residual hydroxyl content of 15-22 wt% (ensuring the compatibility of PVB resin with plasticizer and suitable glass transition temperature and adhesive performance), butyral content of 70-85% (ensuring the flexibility of PVB resin and Optical transparency), residual acetate content ≤1.5wt% (ensuring the thermal stability and aging resistance of PVB resin); the printing surface of the PVB substrate layer is subjected to corona treatment or low-temperature plasma treatment to ensure that its surface energy is not less than 42mN / m; the local metallized pattern layer is formed by digital inkjet printing and drying and curing of metallic effect pigment printing ink on a predetermined area of ​​the printing surface of the PVB substrate layer; the metallic effect pigment printing ink includes special effect metallic pigment, a binder resin compatible with the PVB resin in the PVB substrate layer, solvent and functional additives, wherein the special effect metallic pigment is a flake pigment with an average particle size d50 of 0.5-5.0μm and a maximum particle size D100 of not more than 10μm.

[0008] In one embodiment, the thickness of the PVB substrate layer is 0.38-1.52 mm, adapting to different laminated glass requirements.

[0009] In one embodiment, the PVB substrate layer has the following composition and proportions: PVB resin: 100 parts by weight; plasticizer: 34-35 parts by weight; antioxidant: 0.05-0.1 parts by weight; UV stabilizer: 0.05-0.1 parts by weight; light stabilizer: 0.03-0.05 parts by weight; modified nano-silica: 0.8-1.2 parts by weight; γ-glycidyl etheroxypropyltrimethoxysilane: 0.08-0.12 parts by weight; polydopamine-modified bacterial cellulose: 0.35-0.45 parts by weight; dispersant: 0.04-0.08 parts by weight; defoamer: 0.01-0.03 parts by weight; wherein the modified nano-silica is obtained by modifying nano-silica with γ-glycidyl etheroxypropyltrimethoxysilane; and the polydopamine-modified bacterial cellulose is obtained by in-situ deposition of polydopamine on the surface of bacterial cellulose.

[0010] In one embodiment, the PVB resin is obtained by condensation reaction of polyvinyl alcohol and n-butyraldehyde in an acidic aqueous medium in the presence of a dispersant. The dispersant is a composite system of β-cyclodextrin and sodium nitrate in a mass ratio of (1-3):(4-8) (preferably 1:3), and the amount of dispersant added is 25-55% of the mass of polyvinyl alcohol.

[0011] In a preferred embodiment, the preparation of the PVB resin includes the following steps: 1) Adding 100 parts by weight of polyvinyl alcohol to 1000-1200 parts by weight of water, stirring at 90-95°C for 1-3 hours to obtain a homogeneous and transparent solution, then cooling to 28-32°C, adding 5-15 parts by weight of β-cyclodextrin, stirring for 0.5-1.5 hours to completely dissolve it, adding 20-40 parts by weight of sodium nitrate, and continuing to stir for 25-35 minutes to form a homogeneous PVA-β-CD-NaNO3 composite solution; 2) Stirring state Next, slowly add 125-130 parts by weight of n-butyraldehyde to the PVA-β-CD-NaNO3 composite solution. After the addition is complete, maintain the temperature at 28-32℃ for 20-40 minutes. Then add 2-4 parts by weight of 10wt% nitric acid solution and maintain the temperature for 2.5-3.5 hours. 3) After the reaction is complete, slowly add NaOH solution to adjust the pH of the system to 7.5-8.0. Continue to maintain the temperature and stir for 20-40 minutes. Filter to separate the PVB wet filter cake. First, disperse the PVB wet filter cake in 0.5wt% NaOH solution at 40℃. Soak the PVB filter cake in NaOH solution for 10-15 hours, then wash it with alkali. Next, wash the PVB filter cake with a mixed solvent of ethanol / water in a 1:1 volume ratio at 50°C for 2-3 times with stirring, each time for 20-40 minutes. Finally, wash it thoroughly several times with hot deionized water at 60-70°C until the conductivity of the washing solution is close to the background value of deionized water, thus obtaining a pure wet PVB filter cake. Dry, pulverize, and sieve to obtain powdered PVB resin.

[0012] In a preferred embodiment, the polyvinyl alcohol has a degree of alcoholysis ≥99% and a degree of polymerization of 1700-1800.

[0013] One embodiment of the preparation of the modified nano-silica includes the following steps: dispersing 1-2 parts by weight of nano-silica in 10-20 parts by weight of anhydrous ethanol, adding 0.1-0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane, stirring and reacting at 60-70°C for 2-3 hours, centrifuging, washing with ethanol, and vacuum drying to obtain modified nano-silica.

[0014] One embodiment of the preparation of polydopamine-modified bacterial cellulose includes the following steps: immersing a bacterial cellulose membrane in a Tris-HCl buffer solution containing 0.1 wt% dopamine hydrochloride for 10-14 hours to deposit polydopamine in situ on the surface of the bacterial cellulose membrane, removing the membrane, washing it with deionized water, freeze-drying it, and pulverizing it to obtain polydopamine-modified bacterial cellulose.

[0015] In a preferred embodiment, the concentration of the Tris-HCl buffer is 10 mmol / L.

[0016] In one embodiment, the plasticizer in the PVB substrate layer is selected from one or more of the following: triethylene glycol di-2-ethylhexanoate, triethylene glycol di-2-ethylbutyrate, triethylene glycol dioctanoate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethylbutyrate, 1,3-propanediol di-2-ethylbutyrate, and 1,4-butanediol di-2-ethylbutyrate.

[0017] In one embodiment, the antioxidant in the PVB substrate layer is selected from 2,6-di-tert-butyl-p-cresol (i.e., antioxidant BHT), butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tridecyl phosphite, tri(tertyl) phosphite, triphenyl phosphite, trinonylphenyl phosphite, pentaerythritol diphosphite, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (i.e., antioxidant BHT). The compound system comprises one or more of the following: agent 1010, tris(2,4-di-tert-butylphenyl) phosphite (i.e., antioxidant 168), bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 4,4'-butylidene-bis-(3-methyl-6-tert-butylphenol), and 1,1,3-tris-(2-methyl-hydroxy-5-tert-butylphenyl)butane, preferably a composite system in which the mass ratio of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester to tris(2,4-di-tert-butylphenyl) phosphite is 1:1.

[0018] In one embodiment, the UV stabilizer in the PVB substrate layer is selected from one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-benzotriazole, 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (i.e., UV-326), 2-(5-chloro-2H-benzotriazole-2-yl)-4,6-bis(1,1-dimethylethyl)phenol, and hexamethylphosphoric acid triamine.

[0019] In one embodiment, the light stabilizer in the PVB substrate layer is selected from one or more of HALS-944, HALS-622, HALS-119, and HALS-2020.

[0020] In one embodiment, in the PVB substrate layer, the dispersing agent is a high molecular weight block copolymer dispersant (e.g., Evonik's TEGO Dispers 685, BASF's EFKA FA 4674 or IRGASTAT P 22, BYK Chemical's DISPERBYK-2155, and Shanghai Huiping Chemical's Hyper 732), and the defoaming agent is a polyether-modified polysiloxane (e.g., Evonik's TEGO Airex 920, BYK Chemical's BYK-1799, Shin-Etsu Chemical's KP-333 or KP-341, Momentive's SILQUEST® A-1230, and Guangzhou Jibisheng's Greesil DF-151).

[0021] In one embodiment, the special effect metallic pigment in the printing ink is a mica-based metallic pigment (e.g., Merck Ronastan® Sparkling series) or an aluminum flake pigment (e.g., fine-particle aluminum pigment paste for solvent-based inkjet printing from Starlink or ECARX).

[0022] In one embodiment, in a metallic effect pigment printing ink, the binder resin is selected from one or more combinations of polyurethane resin, acrylic resin, polyvinyl butyral resin, and epoxy resin.

[0023] In one embodiment, in a metallic effect pigment printing ink, the solvent is selected from one or more mixtures of ketones, esters, and alcohols. The ketones include acetone, butanone, methyl isobutyl ketone, and cyclohexanone. The esters include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate. The alcohols include ethanol, isopropanol, n-propanol, and n-butanol. Preferably, the solvent is a mixed solvent of ketones and esters, for example, a mixed solvent with a mass ratio of ethyl acetate:butanone:propylene glycol methyl ether acetate of 5:3:2.

[0024] In one embodiment, the functional additives in the metallic effect pigment printing ink include vinyl chloride-vinyl acetate copolymer, silane coupling agent, dispersant, leveling agent, and defoamer.

[0025] In a preferred embodiment, the metallic effect pigment printing ink has the following composition and proportions: special effect metallic pigment: 5–25 parts by weight; binder resin: 5–20 parts by weight; vinyl chloride-vinyl acetate copolymer: 3–5 parts by weight; silane coupling agent: 2.0–3.0 parts by weight; solvent: 60–85 parts by weight; dispersant: 0.5–3 parts by weight; leveling agent: 0.1–1 parts by weight; defoamer: 0.1–1 parts by weight.

[0026] In a preferred embodiment, the silane coupling agent is KH560.

[0027] In a preferred embodiment, the dispersant is a polymeric block copolymer (e.g., BYK-2150); the leveling agent is selected from one or more of polyether-modified polysiloxanes (e.g., BYK-333, TEGO Glide 410), acrylates (e.g., BYK-358N), and fluorocarbon-modified polymers (e.g., EFKA-3777); and the defoamer is selected from one or more of mineral oil-based defoamers (e.g., BYK-051), polysiloxane emulsions (e.g., BYK-017), and non-silicone defoamers (e.g., BYK-055).

[0028] A method for preparing a PVB interlayer with locally metallic patterns includes the following steps: a) PVB substrate preparation: PVB resin, plasticizer, antioxidant, UV stabilizer, light stabilizer, modified nano-silica, γ-glycidyl etheroxypropyltrimethoxysilane, polydopamine-modified bacterial cellulose, dispersant, and defoamer are melt-blended and extruded to obtain a PVB substrate layer; b) Ink formulation: Special effect metallic pigments, binder resin, solvent, and functional additives are dispersed by high-speed stirring and nano-scale milling, and finally filtered through a 1-5μm... a) Filtering with a precision filter to obtain metallic effect pigment printing ink; c) Surface treatment: Perform corona treatment or low-temperature plasma treatment on the surface of the PVB substrate layer to be printed, so that its surface energy is not less than 42mN / m; d) Digital printing: Using an industrial-grade piezoelectric inkjet printing system, print the metallic effect pigment printing ink obtained in step b) onto a predetermined area of ​​the surface of the PVB substrate to be printed on, according to a preset digital pattern file; e) Drying and curing: Drying in circulating hot air at 40-80℃ for 1-10 minutes to dry and cure the ink on the surface of the PVB substrate layer to be printed, thereby obtaining a PVB interlayer with a locally metallic pattern.

[0029] In one embodiment, step a) involves premixing the materials of each component uniformly before melt-blending and extrusion. The premixing operation is as follows: first, the modified nano-silica, polydopamine-modified bacterial cellulose, dispersant, defoamer, γ-glycidyl etheroxypropyltrimethoxysilane and a portion of the plasticizer are mixed at high speed in a small planetary mixer for 15-25 minutes to form a uniform "nano-masterbatch slurry"; then, in a high-speed mixer, PVB resin, the remaining plasticizer, antioxidant, UV stabilizer and light stabilizer are added, and after mixing at low speed for 3-8 minutes, the "nano-masterbatch slurry" is added, and high-speed mixing is carried out for 10-20 minutes to ensure that all components are uniformly dispersed.

[0030] In one embodiment, in step a), a twin-screw extruder is used to melt-blend and extrude to form a PVB substrate layer. The temperature of the twin-screw extruder is 145°C in the feeding section, 155°C in the melting section, 160°C in the blending section, 158°C in the homogenization section, and 155°C in the die head / mold. Two-stage vacuum exhaust (vacuum degree <-0.095 MPa) is set after the melting section to thoroughly remove moisture, air, and low-molecular-weight volatiles. A 200-mesh filter is installed in front of the die head to filter out possible gels or impurities. The blended melt is extruded through a T-shaped coat hanger die and calendered through a three-stage mirror cooling roller (temperature setting: 80°C→60°C→25°C).

[0031] In a preferred embodiment, in step a), the extruded PVB substrate is wound up, and the wound PVB substrate is left to stand and mature in a constant temperature room of 40-45°C for 7 days to eliminate internal stress and stabilize dimensions and optical properties.

[0032] In one embodiment, step b) involves first pre-dispersing the special effect metallic pigment, dispersant, and a portion of the solvent at high speed, then adding the binder resin, remaining solvent, and other additives (vinyl chloride-vinyl acetate copolymer, silane coupling agent, leveling agent, and defoamer), followed by high-speed stirring and nano-level grinding and dispersion, and finally filtering through a 1-5μm precision filter to obtain a uniform and stable metallic effect pigment printing ink.

[0033] A laminated glass comprises two layers of glass and a PVB interlayer with a partially metallized pattern, sealed between the two layers of glass. This laminated glass can be used in architecture (curtain wall decoration, partitions), automobiles (sunroof shading, window markings), interior decoration (art glass), and other fields.

[0034] Compared with existing technologies, this invention has the following significant advantages: 1. By limiting the critical particle size of the special effect metallic pigment (d50 0.5-5.0μm, D100≤10μm), this invention, in synergy with resin, solvent, and functional additives, effectively solves the clogging and dispersion problems of flake metallic pigments in digital inkjet printing, achieving a technological breakthrough; 2. Relying on digital inkjet printing technology, this invention can achieve precise printing of any complex graphics (such as logos, QR codes), gradient colors, and multi-color overprinting, meeting the needs of small-batch and customized production; 3. This invention forms a locally metallic pattern layer by locally printing metallic effect pigment printing ink on the surface of a PVB substrate layer. When the PVB substrate layer and the locally metallic pattern layer on its surface form a PVB interlayer, it is sealed when applied in laminated glass. Sandwiched between two layers of glass, the metallic pattern is embedded within the laminated glass, creating a unique three-dimensional and depth effect with a strong metallic texture. Furthermore, the metallic pattern is protected by the glass and PVB substrate layer, making it scratch-resistant, weather-resistant (UV resistant, high and low temperature resistant), and will not peel or fade over long-term use. 4. The PVB interlayer with partial metallic patterns provided by this invention only prints ink containing expensive metallic pigments in a predetermined area of ​​the PVB substrate layer, increasing material utilization by over 60%. Compared to a fully metallic PVB interlayer, production costs are reduced by 30-50%, making it particularly suitable for customized orders. 5. This invention can precisely achieve "high light transmittance in non-patterned areas and high reflectivity / shading in patterned areas." The spatial distribution, for example, allows for decoration of the building curtain wall pattern area without affecting indoor lighting, and the dot matrix pattern area of ​​the car sunroof to achieve partial sun shading, balancing functionality and aesthetics; 6. The PVB substrate layer provided by this invention is made by melt extrusion of PVB resin, plasticizer and other specific functional additives (antioxidant, anti-ultraviolet agent, light stabilizer, modified nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, polydopamine modified bacterial cellulose, etc.), and the PVB resin used has specific parameters limited by residual hydroxyl content, butyral degree and residual acetate content, so that the PVB substrate layer has excellent light transmittance and excellent weather resistance; 7. The surface of the PVB substrate layer provided by this invention is treated with corona or low-temperature plasma before ink printing, and the PVB substrate layer is firmly bonded to the locally metallized pattern layer. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail and completely below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the manufacturer. Embodiment 1

[0036] I. Preparation of PVB Resin 1) Add 100 parts by weight of polyvinyl alcohol (specifically PVA-1799) to 1000 parts by weight of water, stir at 95°C for 3 hours to obtain a homogeneous and transparent solution, then cool to 30°C, add 10 parts by weight of β-cyclodextrin, stir for 1 hour to completely dissolve it, add 30 parts by weight of sodium nitrate, and continue stirring for 30 minutes to form a homogeneous PVA-β-CD-NaNO3 composite solution; 2) Under stirring, slowly add 127.5 parts by weight of n-butyraldehyde to the PVA-β-CD-NaNO3 composite solution. After the addition is complete, keep it at 30°C for 30 minutes to mature, add 3 parts by weight of 10wt% nitric acid solution, and keep it at the temperature for 3 hours; During the reaction, β-cyclodextrin will immediately encapsulate part of the n-butyraldehyde, forming To form a stable micro-dispersed system, avoid the aggregation of n-butyraldehyde oil droplets, and ensure the initial dispersion and reactivity of n-butyraldehyde, sodium nitrate can change the solution environment, thereby affecting the cavity hydrophobicity of β-cyclodextrin, the conformation of PVA chains, and the stability of inclusion complexes. This macroscopically optimizes the dispersion state and reaction kinetics of the entire reaction system, regulates ionic strength, enhances the dispersion effect of β-cyclodextrin, and inhibits premature aggregation of polyvinyl alcohol chains, thus synthesizing PVB resin with a more uniform structure and superior performance; 3) After the reaction is completed, slowly add 0.1M NaOH solution to adjust the pH of the system to 7.5-8.0 to completely terminate the reaction. Continue to keep warm and stir for 30 minutes, filter (or centrifuge), separate the PVB wet filter cake, and first disperse the PVB wet filter cake in 0.5wt% at 40℃. The filter cake was soaked in NaOH solution for 12 hours and then alkaline washed (to saponify residual acetate groups). The alkaline-washed PVB filter cake was then washed three times at 50°C with a 1:1 ethanol / water mixture, each wash lasting 30 minutes. (This mixed solvent effectively dissolves and removes residual low-molecular-weight oligomers, unencapsulated organic impurities, and most of the residual β-CD, which are the main causes of film haze and yellowing. Simultaneously, it has limited solubility for high-molecular-weight PVB resin, resulting in minimal loss.) Finally, the filter cake was thoroughly washed several times with hot deionized water at 65°C until the conductivity of the washing solution approached the background value of deionized water (to ensure the removal of Na+ and NO3-). - After the inorganic ions are completely removed, a pure PVB wet filter cake is obtained, which is then dried (specifically, placed in a vacuum drying oven and dried at 50-60℃ for 24-48 hours until constant weight), pulverized, and passed through an 80-mesh sieve to obtain powdered PVB resin. According to the test, the residual hydroxyl content of the prepared PVB resin is about 20wt%, the butyral content is about 78%, and the residual acetate content is ≤1.2wt%.

[0037] II. Preparation of modified nano silica: 1.5 parts by mass of nano silica (particle size 12±3 nm) were dispersed in 15 parts by mass of anhydrous ethanol, and 0.15 parts by mass of γ-glycidoxypropyltrimethoxysilane were added. The mixture was stirred at 65 °C for 2.5 hours, centrifuged, washed with ethanol, and dried under vacuum at 60 °C to obtain modified nano silica.

[0038] III. Preparation of Polydopamine-Modified Bacterial Cellulose: Bacterial cellulose membranes (fiber diameter 20-50 nm) were immersed in Tris-HCl buffer containing 0.1 wt% dopamine hydrochloride (Tris-HCl buffer concentration 10 mmol / L, pH 8.5) for 12 hours to deposit polydopamine in situ on the surface of the bacterial cellulose membrane. The membranes were then removed, washed with deionized water, freeze-dried, and pulverized to obtain polydopamine-modified bacterial cellulose.

[0039] IV. Preparation of PVB interlayer with localized metallization patterns a) Preparation of PVB substrate: First, 1 part by weight of modified nano-silica, 0.4 parts by weight of polydopamine-modified bacterial cellulose, 0.06 parts by weight of dispersant (TEGO Dispers 685), 0.02 parts by weight of defoamer (TEGO Airex 920), 0.1 parts by weight of γ-glycidyl etheroxypropyltrimethoxysilane, and 5 parts by weight of plasticizer (triethylene glycol di-2-ethylhexanoate, 3GEH) are mixed at high speed for 20 minutes in a small planetary mixer to form a uniform "nano masterbatch slurry"; then, in a high-speed mixer, 100 parts by weight of PVB resin, the remaining 29 parts by weight of plasticizer (triethylene glycol di-2-ethylhexanoate, 3GEH), and 0.08 parts by weight of antioxidant (0.04 parts by weight of antioxidant 1010) are added. +0.04 parts by weight of antioxidant 168), 0.08 parts by weight of UV stabilizer (UV-326), and 0.04 parts by weight of light stabilizer (HALS-944) were mixed at low speed for 5 minutes. Then, "nano masterbatch slurry" was added and mixed at high speed for 15 minutes to ensure uniform dispersion of all components. The uniformly dispersed material was melt-blended and extruded into a PVB substrate layer using a twin-screw extruder. The twin-screw extruder had the following temperatures: feeding section temperature 145℃, melting section temperature 155℃, mixing section temperature 160℃, homogenization section temperature 158℃, and die / mold temperature 155℃. Two-stage vacuum exhaust (vacuum degree <-0.095) was installed after the melting section. MPa), to thoroughly remove moisture, air and low molecular weight volatiles, a 200-mesh filter is installed in front of the die head to filter out possible gels or impurities, the compounded melt is extruded through a T-shaped coat hanger die, and calendered through a three-stage mirror cooling roller (temperature setting: 80℃→60℃→25℃); wound up, the wound PVB substrate is left to stand and mature in a constant temperature room of 40-45℃ for 7 days; a transparent PVB substrate layer with a thickness of about 0.76mm is obtained; b) Ink formulation: first, 15 parts by weight of special effect metallic pigment (inkjet-specific gold mica pigment, Merck Ronaldan® Sparkling Gold, The mixture is first pre-dispersed at high speed with 1.5 parts by weight of dispersant (BYK-2150) and 25 parts by weight of solvent (a mixed solvent of ethyl acetate:butanone:propylene glycol methyl ether acetate in a mass ratio of 5:3:2). Then, 20 parts by weight of binder resin (aliphatic polyurethane resin with a solid content of 40%, 8 parts by weight on a solids basis, Covestro Desmodur® / Desmophen®), the remaining 50 parts by weight of solvent, 4 parts by weight of vinyl chloride-vinyl acetate copolymer (Cholmous' UCAR™ VYHH), 2.5 parts by weight of silane coupling agent (KH560), 0.3 parts by weight of leveling agent (BYK-333), and 0.Two parts by weight of defoamer (BYK-051) are dispersed by high-speed stirring and nano-level grinding (grinding to a fineness ≤1μm), and finally filtered through a 1-5μm precision filter to obtain a uniform and stable metallic effect pigment printing ink; c) Surface treatment: The surface of the PVB substrate layer to be printed is subjected to corona treatment (power 1.5kW) to ensure that its surface energy is not less than 42mN / m; d) Digital printing: Using an industrial-grade piezoelectric inkjet printing system (an industrial inkjet printer with a Ricoh GEN5 printhead), the metallic effect pigment printing ink from step b) is printed onto a predetermined area of ​​the surface of the PVB substrate to be printed, according to a preset digital pattern file (company logo pattern); e) Drying and curing: The ink is dried and cured on the surface of the PVB substrate layer to be printed under circulating hot air at 65℃ for 5 minutes. Finally, the PVB substrate enters a storage unit with adjusted moisture content (adjusted to a moisture content of 0.3%), and after a winding process, a PVB interlayer with a locally metallic pattern is obtained.

[0040] V. Preparation of Laminated Glass The PVB interlayer with locally metallized patterns was used as a pseudo-intermediate film layer in the preparation of laminated glass. Specifically, the prepared PVB interlayer was placed between two pieces of transparent glass (300mm long × 300mm wide × 2mm thick) to obtain a laminate. The laminate was placed in a rubber bag and degassed under a vacuum of 2.6kPa for 20 minutes. While degassed, it was transferred to an oven and then vacuum-pressed at 90°C for 30 minutes to pre-press the laminate. Finally, in an autoclave, the pre-pressed laminate was pressed for 20 minutes at 135°C and 1.2MPa to obtain laminated glass with locally metallized patterns. Example 2

[0041] The difference between this embodiment and Embodiment 1 is as follows: 1) The metal effect pigment printing ink formulation used in the preparation process of the PVB interlayer with localized metallization patterns is different. The specific metal effect pigment printing ink formulation used is as follows: special effect metallic pigment (inkjet-specific silver aluminum paste, Sparkle Silver® series, d50≈2μm): 20 parts by weight; binder resin (50% solids acrylic resin, BASF's ACRYNAL® LR 9007): 10 parts by weight (5 parts by weight based on solids); vinyl chloride-vinyl acetate copolymer (Cholmours' UCAR™ VYHH): 4 parts by weight; silane coupling agent (KH560). 2.5 parts by weight; Solvent (mixed solvent of ethyl acetate:butanone:propylene glycol methyl ether acetate in a mass ratio of 5:3:2): 66 parts by weight; Dispersant (BYK-2150): 1 part by weight; Leveling agent (BYK-333): 0.3 parts by weight; Defoamer (BYK-051): 0.2 parts by weight; 2) In the preparation of PVB interlayer with local metallization pattern, after corona treatment of PVB substrate layer, the digitally printed pattern is a shading dot matrix pattern with gradient density. During drying and curing, it is dried with hot air at 70°C for 4 minutes; the other conditions are the same as in Example 1.

[0042] The difference between Comparative Example 1 and Example 1 is as follows: 1) The PVB substrate layer formulation used in the preparation process of the PVB interlayer with localized metallization pattern is different. The specific formulation of the PVB substrate layer is as follows: PVB resin (Sekisui Chemicals S-LECB): 100 parts by mass; plasticizer (triethylene glycol di-2-ethylhexanoate): 38 parts by mass; antioxidant (BHT): 0.1 parts by mass; UV stabilizer (UV-326): 0.2 parts by mass; 2) The ink formulation used does not contain vinyl chloride-vinyl acetate copolymer and silane coupling agent. The solvent used in the ink is a single methyl ethyl ketone (MEK); the other conditions are the same as in Example 1.

[0043] The difference between Comparative Example 2 and Example 2 is as follows: 1) The PVB substrate layer formulation used in the preparation of the PVB interlayer with localized metallization pattern is different. The specific formulation of the PVB substrate layer is as follows: PVB resin (Sekisui Chemicals S-LECB): 100 parts by mass; plasticizer (triethylene glycol di-2-ethylhexanoate): 38 parts by mass; antioxidant (BHT): 0.1 parts by mass; UV stabilizer (UV-326): 0.2 parts by mass; 2) The ink formulation used does not contain vinyl chloride-vinyl acetate copolymer and silane coupling agent. The solvent used in the ink is ethyl acetate alone; the other conditions are the same as in Example 2.

[0044] Comparative Example 3: This comparative example uses an integral coloring method to prepare a PVB interlayer. Specifically, 100 parts by weight of PVB resin (same as Comparative Example 1), 38 parts by weight of plasticizer (triethylene glycol di-2-ethylhexanoate), 1.5 parts by weight of ordinary-grade golden mica pigment (d50=20-40μm, for extrusion), 0.1 parts by weight of antioxidant BHT, and 0.2 parts by weight of UV stabilizer UV-326 are directly melt-blended using a twin-screw extruder and extruded to produce an integrally golden PVB interlayer sheet with a thickness of 0.76mm. This sheet cannot form any local patterns. The prepared PVB interlayer is used to prepare laminated glass using the method of Example 1.

[0045] Performance Testing: The laminated glass prepared in the examples and comparative examples underwent performance testing, specifically as follows: the resolution / fineness of the pattern on the PVB interlayer of the laminated glass was tested using a visual comparison method combined with an optical microscope / image measuring instrument; the adhesion of the pattern on the PVB interlayer of the laminated glass was tested using the cross-cut adhesion test; the visible light transmittance of the non-patterned area of ​​the laminated glass was tested using the ISO 9050:2003 method; the reflectance (%R) of the patterned area of ​​the laminated glass was tested using the ISO 9050:2003 method; the metallic texture and three-dimensionality of the laminated glass were tested under a D65 standard light source using visual evaluation / sensory assessment; the scratch resistance of the pattern on the PVB interlayer of the laminated glass was tested using the ISO 1518-1:2019 method; and the weather resistance of the laminated glass was tested using a xenon lamp aging test according to ISO 4892-2 for 1000 hours, and the weather resistance was evaluated by the change in color difference ΔE before and after measurement. The test results are shown in Table 1.

[0046] Table 1. Test data of laminated glasses prepared in Examples 1-2 and Comparative Examples 1-3

[0047] As shown in Table 1, the laminated glass using PVB interlayers as the interlayer in Examples 1-2, compared to the traditional overall coloring method in Comparative Example 3, only prints ink containing expensive metallic pigments in a predetermined area of ​​the PVB substrate layer, resulting in lower cost. It also achieves precise spatial distribution of "high-transmittance areas" and "high-reflection / shading areas," and allows for customized patterns, resulting in a more aesthetically pleasing effect. Furthermore, the laminated glass using PVB interlayers as the interlayer in Examples 1-2, compared to the laminated glass using VB interlayers as the interlayer in Comparative Examples 1-2, utilizes a self-made, higher-performance PVB resin as the main material of the PVB substrate layer, and adds modified nano-silica and polydimethylsiloxane to the PVB substrate layer. The performance of PVB substrate was modified by adding additives such as dopamine-modified bacterial cellulose, light stabilizers, and γ-glycidyl etheroxypropyltrimethoxysilane. This effectively improved the weather resistance of the PVB substrate without affecting the substrate layer. In addition, in Examples 1-2, vinyl chloride-vinyl acetate copolymer and silane coupling agent were added to the ink as functional additives. At the same time, a composite solvent was used, which improved the pigment dispersion and adhesion between the ink and the PVB substrate. As a result, the laminated glass prepared in Examples 1-2 had better weather resistance than the laminated glass prepared in Comparative Examples 1-2 without affecting the optical performance (in fact, Examples 1 and 2 had better optical performance than Comparative Examples 1 and 2, respectively).

[0048] In summary, laminated glass using the PVB interlayer provided by this invention as the interlayer film has both aesthetic appeal and functional characteristics, and can be applied in fields such as architecture, automobiles, and interior decoration.

[0049] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A PVB interlayer with a locally metallized pattern, characterized in that, The material comprises a PVB substrate layer and a locally metallized pattern layer formed by digital inkjet printing. The PVB substrate layer is a transparent sheet material, prepared by melt extrusion of PVB resin, plasticizer, antioxidant, UV stabilizer, light stabilizer, modified nano-silica, γ-glycidyl etheroxypropyltrimethoxysilane, polydopamine-modified bacterial cellulose, dispersant, and defoamer. The PVB resin meets the following parameters: residual hydroxyl content of 15-22 wt%, butyral degree of 70-85%, and residual acetate content ≤1.5 wt%. The printing surface of the PVB substrate layer... The surface energy is not less than 42 mN / m after corona treatment or low-temperature plasma treatment; the local metallized pattern layer is formed by digital inkjet printing and drying and curing of metallic effect pigment printing ink on a predetermined area of ​​the surface to be printed on the PVB substrate layer; the metallic effect pigment printing ink includes special effect metallic pigment, a binder resin compatible with the PVB resin in the PVB substrate layer, a solvent and functional additives, wherein the special effect metallic pigment is a flake pigment with an average particle size d50 of 0.5-5.0 μm and a maximum particle size D100 of not more than 10 μm.

2. The PVB interlayer with a locally metallized pattern according to claim 1, characterized in that: The PVB substrate layer has the following composition and proportions: PVB resin: 100 parts by weight; plasticizer: 34-35 parts by weight; Antioxidant: 0.05-0.1 parts by weight; UV stabilizer: 0.05-0.1 parts by weight; Light stabilizer: 0.03-0.05 parts by weight; modified nano silica: 0.8-1.2 parts by weight; γ-glycidyl etheroxypropyltrimethoxysilane: 0.08-0.12 parts by weight; polydopamine-modified bacterial cellulose: 0.35-0.45 parts by weight; dispersant: 0.04-0.08 parts by weight; defoamer: 0.01-0.03 parts by weight; wherein the modified nano silica is obtained by modifying nano silica with γ-glycidyl etheroxypropyltrimethoxysilane; wherein the polydopamine-modified bacterial cellulose is obtained by in-situ deposition of polydopamine on the surface of bacterial cellulose.

3. The PVB interlayer with a locally metallized pattern according to claim 2, characterized in that: The PVB resin is obtained by condensation reaction of polyvinyl alcohol and n-butyraldehyde in an acidic aqueous medium in the presence of a dispersant. The dispersant is a composite system of β-cyclodextrin and sodium nitrate in a mass ratio of (1-3):(4-8). The amount of dispersant added is 25-55% of the mass of polyvinyl alcohol.

4. The PVB interlayer with a locally metallized pattern according to claim 3, characterized in that, The preparation of the PVB resin includes the following steps: 1) Add 100 parts by weight of polyvinyl alcohol to 1000-1200 parts by weight of water, stir at 90-95°C for 1-3 hours to obtain a homogeneous transparent solution, then cool to 28-32°C, add 5-15 parts by weight of β-cyclodextrin, stir for 0.5-1.5 hours to completely dissolve it, add 20-40 parts by weight of sodium nitrate, and continue stirring for 25-35 minutes to form a homogeneous PVA-β-CD-NaNO3 composite solution; 2) Under stirring, add... 125-130 parts by weight of n-butyraldehyde were slowly added dropwise to the PVA-β-CD-NaNO3 composite solution. After the addition was complete, the solution was kept at 28-32℃ for 20-40 minutes for curing. Then, 2-4 parts by weight of 10wt% nitric acid solution were added, and the reaction was maintained at this temperature for 2.5-3.5 hours. 3) After the reaction was completed, NaOH solution was slowly added dropwise to adjust the pH of the system to 7.5-8.

0. The solution was kept at this temperature and stirred for another 20-40 minutes. The mixture was then filtered to separate the wet PVB filter cake. The wet PVB filter cake was first dispersed in a 0.5wt% solution at 40℃. Soak the PVB filter cake in NaOH solution for 10-15 hours, then wash it with alkali. Next, wash the PVB filter cake with a mixed solvent of ethanol / water in a 1:1 volume ratio at 50°C for 2-3 times with stirring, each time for 20-40 minutes. Finally, wash it thoroughly several times with hot deionized water at 60-70°C until the conductivity of the washing solution is close to the background value of deionized water, thus obtaining a pure wet PVB filter cake. Dry, pulverize, and sieve to obtain powdered PVB resin.

5. The PVB interlayer with a locally metallized pattern according to claim 1, characterized in that, In the PVB substrate layer, the plasticizer is selected from one or more of the following: triethylene glycol di-2-ethylhexanoate, triethylene glycol di-2-ethylbutyrate, triethylene glycol dioctanoate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethylbutyrate, 1,3-propanediol di-2-ethylbutyrate, and 1,4-butanediol di-2-ethylbutyrate; the antioxidant is selected from 2,6-di-tert-butyl-p-cresol, butyl hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tridecyl phosphite, tri(tridecyl) phosphite, and triphenyl phosphite. Trinonylphenyl ester, bis(tetranyl)pentaerythritol diphosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 4,4'-butylidene-bis-(3-methyl-6-tert-butylphenol), and 1,1,3-tris-(2-methyl-hydroxy-5-tert-butylphenyl)butane; the UV stabilizer is selected from one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-benzotriazole, and 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5 One or more of chlorobenzotriazole, 2-(5-chloro-2H-benzotriazole-2-yl)-4,6-bis(1,1-dimethylethyl)phenol, and hexamethylphosphoric triamine; the light stabilizer is selected from one or more of HALS-944, HALS-622, HALS-119, and HALS-2020; the dispersing agent is a high molecular weight block copolymer dispersant; and the defoaming agent is a polyether-modified polysiloxane.

6. The PVB interlayer with a locally metallized pattern according to claim 1, characterized in that, In the metallic effect pigment printing ink, the special effect metallic pigment is a mica-based metallic effect pigment or an aluminum flake pigment; the binder resin is selected from one or more combinations of polyurethane resin, acrylic resin, polyvinyl butyral resin, and epoxy resin; the solvent is selected from one or more mixtures of ketones, esters, and alcohols, wherein the ketones include acetone, butanone, methyl isobutyl ketone, and cyclohexanone, the esters include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate, and the alcohols include ethanol, isopropanol, n-propanol, and n-butanol.

7. The PVB interlayer with a locally metallized pattern according to claim 1, characterized in that, In metallic effect pigment printing inks, the functional additives include vinyl chloride-vinyl acetate copolymer, silane coupling agent, dispersant, leveling agent, and defoamer.

8. The PVB interlayer with a locally metallized pattern according to claim 7, characterized in that, The metallic effect pigment printing ink has the following composition and proportions: special effect metallic pigment: 5–25 parts by weight; binder resin: 5–20 parts by weight; vinyl chloride-vinyl acetate copolymer: 3–5 parts by weight; Silane coupling agent: 2.0–3.0 parts by weight; Solvent: 60–85 parts by weight; Dispersant: 0.5-3 parts by weight; Leveling agent: 0.1-1 parts by weight; Defoamer: 0.1-1 parts by weight.

9. A method for preparing a PVB interlayer with a locally metallized pattern according to any one of claims 1-8, characterized in that, The process includes the following steps: a) PVB substrate preparation: PVB resin, plasticizer, antioxidant, UV stabilizer, light stabilizer, modified nano-silica, γ-glycidyl etheroxypropyltrimethoxysilane, polydopamine-modified bacterial cellulose, dispersant, and defoamer are melt-blended and extruded to obtain the PVB substrate layer; b) Ink formulation: Special effect metallic pigments, binder resin, solvent, and functional additives are dispersed by high-speed stirring and nano-scale milling, and finally filtered through a 1-5μm... a) Filtering with a precision filter to obtain metallic effect pigment printing ink; c) Surface treatment: Perform corona treatment or low-temperature plasma treatment on the surface of the PVB substrate layer to be printed, so that its surface energy is not less than 42mN / m; d) Digital printing: Using an industrial-grade piezoelectric inkjet printing system, print the metallic effect pigment printing ink obtained in step b) onto a predetermined area of ​​the surface of the PVB substrate to be printed on, according to a preset digital pattern file; e) Drying and curing: Drying in circulating hot air at 40-80℃ for 1-10 minutes to dry and cure the ink on the surface of the PVB substrate layer to be printed, thereby obtaining a PVB interlayer with a locally metallic pattern.

10. A laminated glass, characterized in that: It includes two layers of glass and a PVB interlayer with a partially metallized pattern as described in any one of claims 1-8, which is sealed between the two layers of glass.

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