WO2011085685A1

WO2011085685A1 - Acid resistant and lead-free glass powder used for dielectric and electronic slurry comprising same

Info

Publication number: WO2011085685A1
Application number: PCT/CN2011/070280
Authority: WO
Inventors: 陈雪生; 李海燕
Original assignee: 四川虹欧显示器件有限公司
Priority date: 2010-01-15
Filing date: 2011-01-14
Publication date: 2011-07-21
Also published as: CN101774766A

Abstract

Disclosed are a type of cost-efficient acid resistant glass powder with low melting point which is free from lead and bismuth, and the electronic slurry comprising the same. The glass powder comprises: 5-25wt% of SiO₂, 5-50wt% of B₂O₃, 5-70wt% of SnO₂, 2-10wt% of BaO, 0-15wt% of Al₂O₃, 0-30wt% of TiO₂, 0-10wt% of ZnO, 0-5wt% of MgO, 0-30wt% of ZrO₂, 0-10wt% of CaO, 0-15wt% of Li₂O, 0-5wt% of Na₂O and 0-5wt% of K₂O. The glass powder or the electronic slurry can be used for forming acid resistant dielectric layers of electronic products and electrical products.

Description

Acid-proof lead-free glass powder for medium and electronic paste including the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-free glass powder for a medium, and more particularly to an acid-resistant lead-free glass powder and an electronic paste comprising the lead-free glass powder, which belong to the field of low-melting glass production. BACKGROUND OF THE INVENTION A plasma display (PDP), as a high-performance flat panel display device, has many advantages such as high response speed, wide viewing angle, vivid color, long life, and wide application environment, and thus is increasingly being applied to various occasions. Market demand is also increasing. In the structure of the PDP, a transparent dielectric layer on the front glass substrate and an adjacent reflective dielectric layer and barrier layer on the rear glass substrate are prepared, which are produced by using a low-melting glass frit, and the manufacturing process generally includes Film formation, drying, sintering and other processes. In the method of fabricating the barrier, screen printing is first used to form a barrier that divides each discharge cell. As technology continues to improve, sandblasting methods have evolved. In recent years, as people's demand for television shifts to high-definition and full-HD, the resolution of PDP needs to be further improved. Therefore, etching and sensitization methods have been developed and applied to the production of high-resolution PDP TVs. . In the fabrication process of the back substrate in which the barrier is formed by etching, first, an ADD electrode for addressing is formed on the surface of the glass substrate, and then a layer of the reflective medium is covered and dried and sintered. Next, a continuous barrier layer is formed on the surface of the reflective dielectric layer and subjected to a drying and sintering process, after which a resist layer having photosensitive properties is formed on the surface of the barrier layer. The resist layer may be a photoresist film (DFR) film having photosensitive properties, or may be a photoresist having etching resistance, and then use a master-pair photoresist layer corresponding to the barrier pattern. Exposure and development are carried out to form a barrier pattern on the photoresist layer. Next, the barrier layer is etched with an acidic etching solution. Since the barrier pattern portion is protected by the photoresist layer and is not etched away, the barrier layer portion not containing the photoresist protective layer is etched away. Finally, the photoresist layer is stripped with an alkaline solution. From the above-described barrier forming process, it is known that the reflective dielectric layer adjacent to the barrier layer is also eroded by the acid solution. Thus, in order to accommodate the etching process, the reflective dielectric layer adjacent to the barrier layer should have sufficient acid resistance. With the improvement of the production process, the dielectric materials are also constantly being updated. The first used dielectric glass powder was a lead-containing product. Lead is a highly toxic heavy metal element that has been restricted or banned in many countries from the use of leaded low glass powder materials in the electronics industry. In order to avoid this problem, some people use lead similar to lead to replace lead to prepare low-melting glass frit. However, the price of bismuth is expensive, and the amount used in the low glass powder is relatively large, generally 30% by weight or more, and the content in the acid-resistant low glass powder is more than 50% by weight. This makes the difference between the low-glass material containing bismuth and the low-glass material containing no bismuth by 3 to 7 times. Therefore, the acid-resistant reflective medium material currently applicable to the etching method to form the barrier is the above-mentioned two kinds of lead-containing or antimony-containing materials. SUMMARY OF THE INVENTION It is an object of the present invention to provide a low melting point, low cost, acid resistant lead-free glass frit and an electronic paste containing the lead-free glass frit. A lead-free glass frit according to an aspect of the invention, comprising: SiO ₂ , B ₂ O ₃ , SnO ₂ and at least one oxide for providing free oxygen. Preferably, the lead-free glass frit comprises 5 to 25 wt% of SiO ₂ , 5 to 50 wt% of B ₂ O ₃ and 5 to 70 wt% of SnO ₂ . Preferably, the at least one oxide for providing free oxygen is a network exosome oxide selected from the group consisting of ZrO ₂ , CaO, BaO, Li ₂ O, Na ₂ O and K ₂ O, the total content being 5 to 30% by weight of the glass powder. In a specific embodiment, the network exosome oxide comprises 0 to 30 wt% of ZrO ₂ , 0 to 10 wt ° /" CaO, 2 to 10 wt% of BaO, 0 to 15 wt% of Li ₂ O and 0 ~ 5 wt% of Na ₂ O+K ₂ O. Preferably, the lead-free glass powder further comprises at least one intermediate oxide in a total amount of 5 to 30% by weight of the glass powder. At least one selected from the group consisting of Al ₂ O ₃ , TiO ₂ , ZnO, and MgO. More preferably, the intermediate oxide contains 0 to 15 wt% of Α1 ₂ Ο ₃ , 0 to 30 wt % of TiO ₂ , 0 ~ 10wt% ZnO and 0~5wt% MgO. The lead-free glass powder according to the present invention has a softening point of 600 ° C or lower, and a linear thermal expansion coefficient of 65 x lO in the temperature range of 25 ~ 300 ° C. ⁷ / ° C to 95 x lO - ⁷ / ° C, and acid etching weight loss rate of 10% or more. The present invention also provides a lead-free glass powder electronic paste, the electronic paste includes The above aspects The lead-free glass powder and the organic vehicle. The lead-free glass powder and the lead-free glass powder electronic paste having the composition of the present invention can be used for forming a transparent dielectric layer, a reflective dielectric layer or a barrier structure in a PDP, particularly when used for forming a reflective dielectric layer, Good acid resistance, can be used with etch barrier materials, and acid barrier to form barrier structures. At the same time, the glass frit of the present invention does not contain heavy metal elements which are highly toxic and various elements are easily available, and the cost is low. BEST MODE FOR CARRYING OUT THE INVENTION In the lead-free glass frit of the present invention, SiO ₂ and B ₂ O ₃ are network-forming oxides which form a network skeleton of a glass system. Among them, SiO ₂ exists in the form of a silicon oxytetrahedron [SiO ₄ ], and the silicon oxytetrahedrons are connected at an angle to form a three-dimensional structure. B ₂ O ₃ in borate glass exists in the form of boron oxytribe [BO ₃ ], which is a two-dimensional space formed by a bridging oxygen-bonded boron-oxygen triangle and a boron-oxygen three-membered ring. The network, which is a layered structure, converts the boron-oxygen triangle [BO ₃ ] to a boron-oxytetrahedron [BO ₄ ] when there is an oxide capable of providing free oxygen, and transforms the structure of boron from a layered structure to a frame-like structure. At the same time, B ₂ O ₃ is a good flux, which can lower the high temperature viscosity of the glass. In the above lead-free glass frit, the content of SiO ₂ is usually between 5 and 25 wt%, and when the content is less than 5 wt%, the physical properties of the formed glass system are deteriorated or the formed glass system is unstable; When the content exceeds 25% by weight, the softening point of the formed glass becomes too high, which may cause the sintering temperature to be too high and the glass substrate to be deformed. The SiO ₂ content is preferably between 5 and 20% by weight, more preferably between 5 and 15% by weight. Within this range, the formation of a stable glass system can be ensured without causing the temperature of the softening point of the glass system to be too high due to the excessive addition of SiO ₂ . The content of B ₂ O ₃ is usually 5 to 50% by weight, and when the content of B ₂ O _{3 is} less than 5% by weight, the glass system tends to become unstable to cause devitrification; when the content of B ₂ O ₃ exceeds 50% by weight, It also causes the softening point of the glass to become higher. In the present invention, the content of B ₂ O ₃ is preferably between 10 and 35 wt%, more preferably between 15 and 25 wt%. Within this range it is ensured that a stable glass system is formed without excessively softening the temperature. The sum of the contents of SiO ₂ and B ₂ O ₃ is usually between 20 and 50% by weight. The tin oxide crystal state has an asymmetric tetragonal pyramid structure, and the introduction of tin oxide can improve the fluxing property of the borosilicate glass, so that the system can have a wide glass forming region without containing lead oxide. The content of tin oxide is usually between 5 and 70% by weight, preferably between 20 and 60% by weight, more preferably between 30 and 50% by weight. If the tin oxide content is too low, the purpose of adjusting the softening point of the glass cannot be achieved; if the tin oxide content is too high, the formed glass system tends to become unstable, and the presence of adjacent structural materials occurs. The risk of reaction. Also included in the lead-free glass frit for a medium of the present invention is at least one network exosome oxide. The chemical bond of the network exosome oxide has strong ionicity, wherein the oxygen ion O ² _ is easy to get rid of the cation bond, is the provider of "free oxygen", acts as a break network, but its cation (especially the highly charged cation) ) It is the accumulation of broken keys. The network excipient oxide is added to adjust the melting point, thermal expansion coefficient, dielectric properties and electrical conductivity of the glass frit. The network exosome oxide which can be used in the present invention may be an alkaline earth metal or an alkali metal oxide, preferably selected from the group consisting of ZrO ₂ , CaO, BaO, Li ₂ O, Na ₂ O, K ₂ O, with preference being given. Contains BaO. In the present invention, the proportion of the total amount of the network external oxide in the lead-free glass powder is preferably between 5 and 30% by weight, wherein preferably 0 to 30% by weight of ZrO ₂ , 0 to 10% by weight of CaO, and 2 to 10% are contained. % BaO, 0 to 15 wt% of Li ₂ O, 0 to 5 wt% of Na ₂ O+K ₂ O, that is, the network in vitro oxide preferably contains BaO, and may further contain CaO, Li ₂ O, Na Any one or more of ₂ O and K ₂ O, the total amount of network intrinsic oxides formed by mixing the above substances in the lead-free glass powder is between 5 and 30% by weight. The glass frit according to the present invention preferably comprises at least one intermediate oxide for adjusting the melting point, dielectric properties and electrical conductivity of the glass frit to obtain a sufficiently low, stable melting point. The intermediate oxygen oxime is selected from the group consisting of Al ₂ O ₃ , TiO ₂ , ZnO, and MgO. This intermediate oxygen oxime has a tendency to capture and give "free oxygen" at the same time. Generally, the electric field strength is large, and the capturing power is large; when the electric field strength is small, the ability is large. The total content of the intermediate oxide may be from 5 to 30%, preferably from 10 to 25%, more preferably from 10 to 15%, based on the total weight of the lead-free glass powder. In a preferred mode of the invention, the intermediate oxide comprises only Al ₂ O ₃ , TiO ₂ and ZnO, more preferably Α1 ₂ Ο ₃ and ZnO. In the lead-free glass frit of the present invention, 1 to 15 wt%, preferably 2 to 10%, for example, 5%, 6%, and 7% of Α1 ₂ Ο ₃ may be used; 0 to 30 wt%, preferably 0 to 15% may be used. More preferably 0 to 10%, most preferably 0 to 5% of TiO ₂ ; 0 to 10 wt%, preferably 5 to 10% of ZnO may be used, 0 to 5 wt% of MgO may be used, and finally, total of intermediate oxides The content is 5 to 30% of the total weight of the lead-free glass powder. The low-melting glass in the present invention is applied in the form of a powder, and the particles of the powder are large, j, generally smaller than

15μηι. According to the glass powder formula of the present invention, various oxide raw materials are mixed together (the oxide raw materials used may also be corresponding hydrates, carbonates, hydrogencarbonates, nitrates, etc.), and the various raw materials are uniformly mixed. Pour the formed mixture into a platinum crucible, and then hold it in an electric furnace at a temperature of 900 ° C ~ 1200 ° C for 30 min ~ 120 min, and quickly pour the molten glass liquid to the surface of the cold laminating machine. And forming glass cullet having a thickness of about 1 mm, and pulverizing the glass cullet in a ball mill, further ball milling or jet milling and grading to obtain a glass powder having a particle size of less than 15 μm. The coefficient of thermal expansion of the low-melting glass powder was measured in accordance with the following procedure. First, the low-melting glass powder to be tested is rolled on a powder mill, and then the rolled sheet is placed in an electric furnace to be sintered in accordance with the actual sintering temperature and time conditions of the slurry. Then, the two surfaces of the sintered glass piece are polished, and then the sample is placed on a thermal dilatometer to heat the sample at a heating rate of 5 ° C / min, and the elongation of the sample is measured, based on Determine the average coefficient of thermal expansion of the test sample in the range of 30 ~ 300 °C. The glass powder of the above-mentioned melting point is mixed with an organic vehicle in a certain ratio, and is formulated into an electronic paste for use in a process of screen printing, coating, etc., and the organic vehicle used for formulating the slurry generally comprises a resin and an appropriate amount of a diluent. The resin used in the present invention may be all kinds of resins generally used in the art, and preferably has low ash residual or no residue after sintering. The resin is usually an oligomer which can be further polymerized under the dry or illumination of the coating. For example, in the present invention, an alkyd resin, a (meth)acrylic resin, a (meth) acrylate resin, an ethyl fiber is preferably used. One or more of cellulose and sulfhydryl cellulose. Alternatively, a polymerizable monomer may be used in place of the resin in the organic vehicle, which polymerizes in the presence of an initiator to increase the consistency and the binder. In the case where the above preferred components are used in the present invention, the total weight of the resin is from 3 to 15% by weight based on the total weight of the organic vehicle. The diluent may be selected from reactive diluents and inert diluents (solvents) as needed. The reactive diluent is a polymerizable monomer which is further polymerized with the above resins, which are well known in the art. The requirement for the solvent component is that the resin has a higher solubility in the solvent and a complete solution is obtained; the solvent does not react with other components in the lead-free glass frit; it should have appropriate volatility for screen printing or The coating process ensures stable viscosity during storage. The solvent preferably used in the present invention is a high boiling point solvent having a boiling point between 150 and 300 ° C at normal pressure. Such solvents include fatty alcohols, fatty alcohol esters, such as: acetate and propionate; terpenes, terpineol; ethylene glycol and its esters, ethyl glycol monobutyl ether and butyl cellosolve B Acid esters; carbitol esters such as butyl carbitol, butyl carbitol acetate and carbitol acetate; Texanol® (2,2,4-trimethyl-1,3-pentane) Alcohol monoisobutyrate) and the solvent formed by their mixing. It is also possible to use an appropriate amount of a plasticizer or a toughening agent in an organic medium to impart better toughness to the dielectric layer and to make the slurry adhesive. The plasticizer may be a variety of organic substances, such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), epoxidized soybean oil, tricresyl phosphate, triphenyl phosphate, sebacic acid. Dioctyl ester, chlorinated paraffin, etc., may be added in an amount of 0 to 10% by weight of the organic vehicle. The total weight of the organic vehicle is from 10 to 40% by weight based on the total weight of the slurry. In order to further improve the properties of the slurry, a dispersant, an anti-settling agent, an antifoaming agent, a leveling agent, a thixotropic modifier, or the like may be optionally added thereto. The glass powder and the organic vehicle are mixed in a certain ratio, and then sufficiently dispersed, rolled, and defoamed to form a transparent medium slurry. When used to form a reflective medium slurry or a barrier slurry, a certain amount of filler such as ZnO, TiO ₂ or the like should also be mixed. Added here as a filler ZnO, TiO ₂ is not replaced as the optional intermediate oxide ZnO, TiO _2, ZnO as the intermediate oxide, TiO ₂ and other materials have been eutectic together, become a mixed The glass system, therefore, the ZnO, TiO ₂ filler in the post-production of the slurry needs to be re-added. The weight of the above filler is 0 to 50% of the weight of the glass powder of the melting point of the glass powder, and if the amount of the filler is more than

50% is likely to cause the formed dielectric film layer to be unstable after sintering. The acid resistance of the above-mentioned melting point glass is measured by the weight loss rate of the glass of the melting point in the acid solution. The specific measurement process is as follows: First, the electronic paste prepared by the low-melting glass powder is printed on the glass substrate by screen printing. A film layer having a certain area and a certain thickness (8-15 μ ηι) is formed thereon, and then the dielectric layer is subjected to a drying and sintering process according to a predetermined drying and sintering temperature curve, and the weight of the glass substrate is weighed and after sintering. The weight of the dielectric layer is determined by the total weight of the dielectric layer and the glass substrate, and then the glass substrate with the dielectric layer is immersed in a certain concentration (usually 1 wt%) of the HNO ₃ solution, and the dielectric layer should be completely immersed in the solution. Leave it at room temperature for more than 60 minutes. After removing the glass substrate with the dielectric layer, rinse it with clean water, dry it and weigh it. The weight loss of the medium is etched by the acid solution and the dielectric layer before etching. The weight ratio is the weight loss rate of the glass in the acid solution. Examples 1 to 5 The specific formulations and properties of the above examples are shown in Table 1: Composition and properties of lead-free glass powder

ZrO ₂ 12 5

TiO ₂ 10 12 10 5

Al ₂ O ₃ 2 5 6 5 5

ZnO 10 10 10 5 5

CaO 5

BaO 10 8 10 7 3

MgO 2

Li ₂ O 2

Na ₂ O 5 5 4 3 2

K ₂ O 2

Softening point (.C) 587 562 541 524 485

TEC

78 81 80 83 85

( lO" ⁷ / ° C )

Etching weight loss rate

7.1 5.7 6.3 2.4 0.3 (%) Comparative Example 1 ~ 4

Table 2: Composition and properties of lead-free glass powder

From the comparison of Table 1 and Table 2, it can be seen that since the present invention uses SnO ₂ , the glass frit according to the present invention has remarkably high acid resistance.

Claims

Claim

A lead-free glass frit characterized by comprising: SiO ₂ , B ₂ O ₃ , SnO ₂ and at least one oxide for providing free oxygen.

2. The lead-free glass frit according to claim 1, comprising 5 to 25 wt% of SiO:

5 to 50 wt% of B ₂ O ₃ and 5 to 70 wt% of SnO ₂ .

3. The lead-free glass frit of claim 1, wherein the at least one oxide for providing free oxygen is a network exosome oxide.

4. The lead-free glass frit according to claim 3, wherein the network exosome oxide is at least one of ZrO ₂ , CaO, BaO, Li ₂ O, Na ₂ O, and K ₂ O. The total content is 5-30% by weight of the lead-free glass powder.

The lead-free glass frit according to claim 4, wherein the network exosome oxide comprises 0 to 30 wt% of ZrO ₂ , 0 to 10 wt% of CaO, 2 to 10 wt% of BaO, 0 to 15 wt% of Li ₂ O and 0 to 5 wt% of Na ₂ O+K ₂ O.

6. The lead-free glass frit according to claim 1, further comprising at least one intermediate oxide having a total content of 5 to 30% by weight of the lead-free glass frit.

The lead-free glass frit according to claim 6, wherein the intermediate oxide is at least one selected from the group consisting of Al ₂ O ₃ , TiO ₂ , ZnO, and MgO.

The lead-free glass frit according to claim 7, wherein the intermediate oxide comprises 0 to 15 wt% of Α1 ₂ Ο ₃ , 0 to 30 wt% of TiO ₂ , 0 to 10 wt% of ZnO, and 0 ~ 5wt% of MgO.

A lead-free glass frit electronic paste, characterized in that the electronic paste comprises the lead-free glass frit according to any one of claims 1 to 8 and an organic vehicle.

10. The lead-free glass frit electronic paste according to claim 9, further comprising a filler selected from the group consisting of ZnO and TiO ₂ .