Glass ink frit for automotive glass as well as preparation method and application of glass ink frit

Abstract

The invention discloses a glass ink frit for automotive glass and a preparation method and application thereof. The invention relates to the field of glass decoration, in particular to a frit of glass ink for automotive glass, which is prepared from the following components in percentage by weight: 40-60% of bismuth oxide, 10-20% of boric oxide, 20-30% of silicon oxide, 3-5% of zinc oxide, 3-5% of lithium carbonate, 3-5% of sodium carbonate and 0-2% of barium carbonate. The initial melting point of the frit is 560 DEG C, and the linear expansion coefficient is 7.9 * 10 <-7 > / . Through a unique formula design, the frit has a low initial melting point of 500-600 DEG C and a low expansion coefficient of (8-10) * 10 <-7 > / DEG C, effectively solves the problems of high-temperature sintering, poor thermal matching performance and unstable color development of the traditional frit, and realizes clear printing of automobile glass patterns and rapid production change of ink, thereby reducing the production cost and improving the production efficiency.

Description

[Technical Field]

[0001] This invention relates to the field of glass decoration, and specifically to the preparation of a frit for automotive glass ink with a low initial melting point and a low coefficient of thermal expansion. This frit is an important component of automotive glass ink. Black automotive glass ink belongs to the category of high-temperature inorganic glass inks. [Background Technology]

[0002] In the automotive glass manufacturing industry, traditional pattern printing mainly relies on ink printing technology. However, this technology has some drawbacks: on the one hand, the clarity of ink-printed patterns is insufficient to meet the increasingly refined and high-end decorative needs of automotive glass. When printing small trademarks, complex geometric patterns, or high-resolution logos, problems such as blurred edges and dot offset often occur, resulting in insufficient product aesthetics and recognizability. On the other hand, the ink printing conversion process is cumbersome. When switching to different product patterns, deep cleaning of printing equipment, replacement of printing plates, and readjustment of parameters are required. This not only consumes a lot of manpower and time costs but also greatly limits production efficiency, making it difficult to quickly respond to diverse market order demands.

[0003] With the innovative application of inkjet printing technology in the glass decoration field, glass ink is gradually becoming a key material to replace traditional inks. Leveraging the non-contact and high-precision printing advantages of inkjet technology, glass ink can precisely control the position and shape of ink droplets, effectively solving the problems of unclear patterns and difficulties in production transitions associated with traditional inks. In the glass ink system, the frit, as the core functional material, directly determines the bonding quality between the ink and the automotive glass substrate, as well as the color development effect of the pattern. The frit melts during high-temperature sintering and forms a strong chemical bond with the glass substrate, while simultaneously encapsulating and dispersing the black pigment, achieving stable and vibrant pattern color development. However, existing glass ink frits generally have performance shortcomings: most frits have excessively high initial melting points, resulting in huge energy consumption and easily causing defects such as thermal deformation and warping in automotive glass; some frits have mismatched coefficients of thermal expansion with automotive glass, generating significant internal stress during sintering and cooling, leading to pattern detachment and glass breakage; furthermore, the poor compatibility between the frit and the black pigment causes pigment agglomeration and uneven color development, severely affecting the visual effect of the printed pattern. Therefore, developing a glass ink frit with a low initial melting point, low coefficient of expansion, and the ability to efficiently coordinate color development with black pigments has become the key to breaking through the bottleneck of automotive glass inkjet printing technology. [Summary of the Invention]

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a glass frit suitable for automotive glass black ink. Through a unique formulation design, it possesses a low initial melting point of 500-600℃ and (8-10)×10 -7With a low coefficient of thermal expansion of / ℃, it effectively solves the problems of high-temperature sintering, poor thermal matching, and unstable color development of traditional frits, enabling clear printing of automotive glass patterns and rapid ink conversion, thereby reducing production costs and improving production efficiency.

[0005] A glass frit for use in automotive glass black ink, comprising, by weight percentage, the following components:

[0006] Bismuth oxide (Bi2O3): 40-60%, as a core flux, can significantly reduce the initial melting point of the frit to 500-600℃, while playing a regulating role in the glass network structure, optimizing the bonding performance between the frit and the automotive glass substrate, and enhancing the adhesion between the two.

[0007] Boron oxide (B2O3): 10-20%, synergistically forms a low-melting-point eutectic system with bismuth oxide, further reducing the melting temperature of the molten block, while improving the stability of the glass phase, reducing the viscosity of the melt, promoting the uniform spreading of the molten block during sintering, and ensuring the full dispersion of the black pigment.

[0008] Silicon oxide (SiO2): 20-30%, as the framework for the glass network, imparts the necessary structural strength and chemical stability to the fused mass, suppresses the chemical erosion sensitivity caused by excessive bismuth oxide, and ensures the stability of the fused mass in the ink system and sintering process.

[0009] Zinc oxide: 3-5%, as a network intermediate, can improve the mechanical strength and anti-crystallization performance of the frit, optimize the adhesion interface between the ink and the automotive glass substrate after sintering, and enhance the dispersion and stabilization effect of the frit on black pigments, thus preventing pigment agglomeration.

[0010] Sodium carbonate: 3-5%, lowers the melting point, allowing raw materials to melt at lower temperatures and saving energy; acts as a flux to promote the melting of refractory materials; regulates the chemical composition, providing sodium to influence the properties of the frit; improves uniformity, making the frit composition more uniform and improving quality stability.

[0011] Barium carbonate: 0-2%, lowers melting temperature; improves chemical stability and enhances acid and alkali resistance; also improves gloss, making product surfaces smoother and brighter.

[0012] Lithium carbonate (Li2CO3): 3-5%, a highly efficient fluxing component. The Li2O produced by its decomposition can further reduce the expansion coefficient of the molten metal, improve the wettability of the ink on the glass surface, promote the tight bonding between the molten metal and the glass substrate, and assist in the uniform color development of black pigments, thereby enhancing the color saturation and uniformity of the pattern.

[0013] Preparation method of glass frit

[0014] Step 1, Raw material pretreatment: Weigh each component raw material accurately according to the above formula. Lithium carbonate needs to be dried at 120℃ for 2 hours in advance to remove free moisture. Pass all raw materials through a 200-mesh sieve to ensure that the raw material particle size is uniform and the impurity content is <0.1%.

[0015] Step 2, Mixing: Place the pretreated raw materials in a planetary mixer and mix at 80 r / min for 30 minutes to ensure that the components are fully and evenly dispersed and the component deviation coefficient (CV) of the mixture is less than 3%.

[0016] Step 3, Melting: Transfer the mixed raw materials to a corundum crucible, place it in an electric furnace, heat it to 800-900℃ at a heating rate of 15℃ / min, and hold it at that temperature for 1-2 hours. Stir it every 30 minutes during this period to ensure that the melt composition is uniform and there is no local overheating.

[0017] Step 4, quenching: Quickly pour the molten glass into water at 25°C for quenching. The quenching time should be controlled within 10 seconds to suppress crystal precipitation and obtain a uniform amorphous structure.

[0018] Step 5, Drying and Pulverizing: Place the quenched glass particles in an 80℃ oven to dry for 4 hours to remove surface moisture; then pulverize them with an air jet mill to an average particle size D50 = 10-15μm, pass them through a 325 mesh sieve, and the residue on the sieve is <0.1%, to obtain glass frit powder.

[0019] A black glass ink, by weight percentage, comprises: 35-45% frit powder, 10-20% black pigment, 35-45% organic carrier, 2-5% additives, and 2-5% dispersant.

[0020] Preferably, the black pigment is spinel-type inorganic copper chromium black; the organic carrier is selected from ethylene glycol, isopropanol, butyl acetate, tert-butanol, propylene glycol diacetate, dipropylene glycol methyl ether, diethylene glycol monobutyl ether, propylene glycol methyl ether acetate, tripropylene glycol methyl ether, and petroleum ether, or a mixture of multiple compounds in any proportion; the additives include leveling agents, which are fluorocarbon surfactants; the dispersants are acrylate copolymers and polyurethane polymers, specifically including BYK Chemicals' DISPERBYK-111, DISPERBYK-180, and DISPERBYK-163, one of which can be selected or a mixture of multiple dispersants in a specific proportion; the ink viscosity is 10-20 mPa·s.

[0021] The application of black glass ink in automotive glass pattern printing involves forming patterns on the surface of automotive glass through inkjet printing or screen printing processes. After sintering at 580-620℃, the fused material is firmly bonded to the automotive glass substrate, resulting in uniform color development, high saturation, and significantly improved production efficiency.

[0022] Compared with existing technologies, the present invention has the following advantages:

[0023] 1. Low-temperature and high-efficiency sintering: The initial melting point of the frit of this invention is as low as 500-600℃, and the actual sintering temperature can be controlled at 580-620℃, which effectively avoids defects such as deformation and warping caused by high-temperature sintering of automotive glass, and significantly improves production efficiency.

[0024] 2. Excellent thermal compatibility: The linear expansion coefficient of the fused mass is as low as (7-9)×10⁻⁶. -7 / ℃

[0025] (20-300℃), with automotive glass substrate (8×10 -7 The coefficient of thermal expansion (C / ℃) is close to that of the glass, resulting in minimal internal stress during sintering and cooling (interfacial stress < 10MPa), effectively preventing pattern peeling and glass breakage, and significantly improving product reliability and service life.

[0026] 3. High definition and stable color development: After grinding, the frit has a particle size of approximately 0.4-0.7μm, which enables precise control of ink layer thickness and shape in inkjet printing, resulting in good edge resolution of the pattern. At the same time, the good compatibility between the frit and the black pigment ensures that the pigment is evenly dispersed and stably developed during the sintering process. The printed pattern has uniform color, high saturation, and a color difference ΔE < 1, meeting the visual requirements of high-end automotive glass decoration.

[0027] 4. Convenient and efficient production switchover: The glass ink prepared based on the frit of this invention is suitable for printing on automotive glass. When switching to different product patterns, only the printhead needs to be cleaned. There is no need to adjust the parameters of core equipment such as kilns. The production switchover time is shortened from the traditional 40-50 minutes to less than 15 minutes, which greatly reduces labor and time costs and significantly improves the company's response speed to market orders and production flexibility.

[0028] 5. Through a unique formula design, it possesses a low initial melting point of 500-600℃ and (8-10)×10 -7 With a low coefficient of thermal expansion of / ℃, it effectively solves the problems of high-temperature sintering, poor thermal matching, and unstable color development of traditional frits, enabling clear printing of automotive glass patterns and rapid ink conversion, thereby reducing production costs and improving production efficiency.

Detailed Implementation Methods

[0029] Example 1:

[0030] Preparation of standard glass frit:

[0031] Weigh out 45% bismuth oxide, 13% boron oxide, 28% silicon oxide, 5% zinc oxide, 4% lithium carbonate, 3% sodium carbonate, and 2% barium carbonate by weight percentage. After drying the lithium carbonate at 120°C for 2 hours, pass it through a 200-mesh sieve along with the other raw materials.

[0032] Place the sieved raw materials into a planetary mixer and mix at 80 rpm for 30 minutes.

[0033] Place the mixed raw materials into a corundum crucible, heat it to 900℃ in an electric furnace at a rate of 15℃ / min, and hold it at that temperature for 1.5 hours, stirring 3 times during the process.

[0034] The molten liquid was poured into water at 25°C for quenching, dried at 80°C for 4 hours, and then pulverized to D50 = 12μm using an air jet mill and passed through a 325-mesh sieve.

[0035] The prepared frit was subjected to performance tests, and the results showed that the initial melting point was between 550-600℃ and the coefficient of linear expansion was 7.9×10⁻⁶. -7 / ℃ (20-300℃).

[0036] Example 2: Preparation and inkjet application of glass ink;

[0037] Ink preparation: Take 35% of the glass frit powder prepared in Example 1, 18% copper chromate black, 40% isopropanol, 3% acrylic resin, 3% dispersant, and 1% leveling agent. Grind the copper chromate black, glass frit, isopropanol, acrylic resin, and dispersant in a sand mill for 6 hours until the particle size is ≤0.8μm. Then adjust the viscosity to 10-20mPa·s and filter through a 1-micron filter to obtain black glass ink.

[0038] Inkjet test: Using a XARK 2012 printhead, inkjet patterns were printed onto the surface of automotive glass. The inkjet film thickness was 15-30μm, and the film was sintered at 590℃ for 4-6 minutes. The results showed that the pattern edges were clear and jagged, the colors were uniform, the saturation was high, the pattern was realistic, and the color difference ΔE = 0.8.

[0039] Comparative Example: Comparison of Traditional Glass Ink Fuse

[0040] Commercially available ordinary glass ink frit (initial melting point 750℃, coefficient of thermal expansion 10×10) is used. -7 The ink was prepared and printed using the same process ( / ℃). After sintering at 900℃, two cracks appeared at the edge of the glass, the pattern color was uneven, and the color difference ΔE=2.5; during the switchover, the kiln refractory material needed to be replaced and the parameters adjusted, which took 40 minutes. In comparison, the frit of this invention has significant advantages in sintering temperature, thermal stability, color development effect, and switchover efficiency.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the technical principles of the present invention. These changes, modifications, substitutions and variations should also be considered within the protection scope of the present invention.

Claims

1. A frit for glass ink used in automotive glass, characterized in that, The frit, by weight percentage, comprises the following components: 40-60% bismuth oxide, 10-20% boron oxide, 20-30% silicon oxide, 3-5% zinc oxide, 3-5% lithium carbonate, 3-5% sodium carbonate, and 0-2% barium carbonate; the initial melting point of the frit is 560°C, and the coefficient of linear expansion is 7.9 × 10⁻⁶ at 20-300°C. -7 / ℃.

2. A method for preparing the fused block according to claim 1, characterized in that: include: Raw material pretreatment, mixing, melting at 800-900℃ for 1-2 hours, quenching, drying and pulverizing to a particle size D50 = 10-15μm.

3. A black glass ink comprising the glass ink frit of claim 1, characterized in that, By weight percentage, it includes: 35-45% frit powder, 10-20% black pigment, 35-45% organic carrier, 2-5% additives and 2-5% dispersant.

4. The black glass ink according to claim 3, characterized in that, The black pigment is spinel-type inorganic copper chromium black; the organic carrier is one or a mixture of multiple compounds selected from ethylene glycol, isopropanol, butyl acetate, tert-butanol, propylene glycol diacetate, dipropylene glycol methyl ether, diethylene glycol monobutyl ether, propylene glycol methyl ether acetate, tripropylene glycol methyl ether, and petroleum ether; the additives include leveling agents, which are fluorocarbon surfactants; the dispersant is an acrylate copolymer and a polyurethane polymer; and the ink viscosity is 10-20 mPa·s.

5. The black glass ink according to claim 4, characterized in that, The dispersant is one or more of BYK Chemical's DISPERBYK-111, DISPERBYK-180, and DISPERBYK-163.

6. The application of the black glass ink according to any one of claims 3-5 in automotive glass pattern printing, characterized in that, Patterns are formed on the surface of automotive glass using inkjet printing or screen printing processes. After sintering at 580-620℃, the frit is firmly bonded to the automotive glass substrate, resulting in uniform color development, high saturation, and significantly improved production efficiency.