JPH0366266B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a low-melting glass composition, particularly a glass composition that is transparent, has excellent acid resistance, and is resistant to defects such as reboiling, and is used as a frit for enamel. [Background technology] Conventional enamel frits are baked onto a substrate at 800 to 850°C, and a glassy film with excellent surface properties (acid resistance, alkali resistance, boiling resistance, weather resistance, etc.) is baked onto the substrate. It can be formed into However, since the firing temperature is quite high,
When baking a thin iron plate or the like, the amount of thermal deformation of the thin iron plate increases, resulting in poor dimensional accuracy of the resulting enamel product. In order to solve this problem, it was considered to use glass frit with a low melting point as a frit for enamel, but such frit is harmful because it contains large amounts of pollutants such as Pb, Cd, and Ag. , and because Ag and the like are expensive, it had the disadvantage of being expensive. Moreover, the surface properties of the glassy coating formed by such frits are much worse than those formed by the above-mentioned enamel frits, so that they can hardly be put to practical use. [Object of the Invention] The present invention has been made in view of the above circumstances, and an object thereof is to provide a low-melting point glass composition that forms a glassy film with excellent surface performance. [Disclosure of the Invention] The inventors believe that in order to develop a frit that can be baked onto a substrate with a large amount of thermal deformation, such as a thin iron plate, it is first necessary to know its thermal deformation characteristics. , I did the following: That is, thin iron plates such as general cold-rolled steel plates and enameled steel plates with a thickness of 1 mm were heated at 700°C, 800°C, and 890°C for 10 minutes each, and the amount of thermal deformation in each case was determined. The results are shown in the drawing. In the figure, curve A is a thermal deformation curve of a general cold-rolled steel plate with a thickness of 1 mm, and curve B is a thermal deformation curve of a steel plate for enameling. As is clear from curves A and B, there is almost no thermal deformation when the heating temperature is 700°C, whether it is a general cold-rolled steel plate or a steel plate for enameling, and the amount of thermal deformation increases when the temperature exceeds the transformation point of iron (720°C). Recognize. On the other hand, from the viewpoint of surface performance, there has recently been an increasing demand for enamel with even better acid resistance. Examples include storage tanks, acid-resistant containers, or enameled IC boards that are in constant contact with strong acids. Since enamel IC boards are to be incorporated into various devices, it is important to make the steel plate particularly thin and lightweight, and it is desirable to eliminate thermal deformation caused by firing as much as possible. Furthermore, since the substrate is often subjected to acid treatment during circuit formation, it can be said that this material is required to have particularly strong acid resistance. Based on the above findings, the inventors then developed a vitreous film that does not contain harmful substances, is inexpensive, and has even better surface performance and acid resistance.
We believed that it was necessary to conduct research and development of glass compositions that could be formed by firing at temperatures below 700°C, and conducted various experiments and research. the result,
We have discovered that such a purpose can be achieved with a glass composition having the composition shown below, and hereby,
completed this invention. That is, the first invention includes SiO ₂ ; 52 to 62 wt% (weight) B ₂ O ₃ ; 7 to 13 wt% TiO ₂ +ZrO ₂ ; 7 to 14 wt% Na ₂ O + Li ₂ O + K ₂ O; 18 to 26 wt% [However, , (TiO ₂ )/(ZrO ₂ ) weight ratio; 1/5 to 2/1 (Na ₂ O)/(Li ₂ O) weight ratio; 1/1 to 5/1 (K ₂ O)/(Na ₂ O) Weight ratio: over 0 and 3/1
_A glass _composition consisting of
7.0wt% is added, and part of the above oxide is F ₂
The gist is a low melting point glass composition in which fluoride is substituted by 1.5 to 5.0 wt% in terms of fluoride. The second invention is as follows: SiO ₂ ; 52 to 62 wt% B ₂ O ₃ ; 7 to 13 wt% TiO ₂ + ZrO ₂ ; 7 to 14 wt% Na ₂ O + Li ₂ O + K ₂ O; 18 to 26 wt% [However, (TiO ₂ ) /( _ZrO2 ) weight ratio; 1/5 to 2/1 ( _Na2O )/( _Li2O ) weight ratio; 1/1 to 5/1 ( _K2O )/( _Na2O ) weight ratio; 0 or more and 3/1 or less] MgO, CaO, SrO,
At least one metal oxide selected from the group consisting of BaO, ZnO and Al ₂ O ₃ is added at 0.5 to 5.0 wt%, and MoO ₃ and/or WO ₃ is added at 0.5 wt%.
~7.0wt% is added, and some of the above oxides are
The gist of the present invention is a low melting point glass composition in which fluoride is substituted by 1.5 to 5.0 wt% in terms of _F2 . Note that the glass compositions of the first and second inventions correspond to the following glass compositions whose compositions are expressed in mol%. That is, in the first invention, _SiO2 ; 56 to 63 mol% _B2O3 ; 6 to 10 mol% _TiO2 + _ZrO2 ; 5 to 10 mol% _Na2O + _Li2O + _K2O ; 23 _to 26 mol% [ However, (TiO ₂ )/(ZrO ₂ ) molar ratio; 1/3 to 3/1 (Na ₂ O)/(Li ₂ O) molar ratio; 2/3 to 4/1 (K ₂ O)/(Na ₂ O) molar ratio; over 0 4/1
_A glass _composition consisting of
5.0 mol% is added, and some of the above oxides are
The second invention corresponds to a low melting point glass composition in which fluoride is substituted by 3 to 7 mol% in terms of F ₂ , SiO ₂ ; 56 to 63 mol % B ₂ O ₃ ; 6 to 10 Mol% TiO ₂ + ZrO ₂ ; 5 to 10 mol % Na ₂ O + Li ₂ O + K ₂ O; 23 to 26 mol % [However, (TiO ₂ )/(ZrO ₂ ) molar ratio; 1/3 to 3/1 (Na _{2 MgO , CaO} , SrO,
At least one metal oxide selected from the group consisting of BaO, ZnO and Al ₂ O ₃ is added in an amount of 0.5 to 5.0 mol %, and MoO ₃ and/or WO ₃ are added.
This corresponds to a low melting point glass composition in which fluoride is added in an amount of 0.5 to 5.0 mol %, and a portion of the above oxide is replaced with a fluoride by 3 to 7 mol % in terms of F ₂ . Below, these two inventions will be explained in detail. In this invention, the reason why the composition is limited as described above is as follows. That is, when SiO ₂ exceeds 62 wt%, the softening temperature of the glass composition becomes high, and firing at 700° C. is no longer possible. On the other hand, if the content is less than 52 wt%, the acid resistance and hot water resistance of the resulting glassy film will be significantly reduced. When B ₂ O ₃ exceeds 13 wt%, the acid resistance and hot water resistance of the resulting glassy film decrease, and when it becomes less than 7 wt%, the softening temperature of the glass composition increases. When the total amount of TiO ₂ and ZrO ₂ exceeds 14 wt%, the softening temperature of the glass composition becomes high, crystallization occurs, and the composition becomes opalescent, resulting in loss of transparency. Conversely, when the content is less than 7 wt%, the hot water resistance and acid resistance of the vitreous film decrease and it becomes semi-emulsified. The mutual proportion of TiO ₂ and ZrO ₂ is (TiO ₂ )/(ZrO ₂ ) weight ratio,
When the ratio is less than 1/5, acid resistance decreases, and when it exceeds 2/1, crystallization occurs. When the total amount of Na ₂ O, Li ₂ O, and K ₂ O exceeds 26 wt%, acid resistance and hot water resistance will decrease significantly, and the thermal expansion coefficient will also exceed 11.0 × 10 ^-6 /℃. As it gets older, it becomes difficult to bake onto the iron plate, and conversely,
When the content is less than 18wt%, the softening temperature becomes high. And the mutual ratio of Na ₂ O and Li ₂ O is
When the (Na ₂ O)/(Li ₂ O) weight ratio is less than 1/1, crystallization occurs and the softening temperature also increases.
The luster caused by firing no longer appears. vice versa,
When the (Na ₂ O)/(Li ₂ O) weight ratio exceeds 5/1, the softening temperature becomes high and the acid resistance and hot water resistance of the resulting glassy film deteriorate. Also,
When the (K ₂ O)/(Na ₂ O) weight ratio exceeds 3/1, the coefficient of thermal expansion exceeds 11.0×10 ^-6 /℃,
In addition, acid resistance also deteriorates. When the fluoride exceeds 5.0 wt% in terms of _F2 , it becomes semi-emulsified, and when it becomes less than 1.5 wt%, the softening temperature increases and the luster caused by firing no longer appears. Glass compositions consisting of the above components can also achieve the intended purpose, but in order to further improve chemical resistance, MgO, CaO, SrO, BaO, ZnO
At least one metal oxide selected from the group consisting of and Al ₂ O ₃ can be added. The appropriate amount of addition is 0.5 to 5.0 wt% relative to 100 wt% of the glass (mother glass) before addition. If the amount is less than 0.5wt%, no effect is observed, and if it exceeds 5.0wt%, the softening temperature of the glass increases and the glass becomes prone to devitrification. I can't expect much. In the low melting point glass composition according to the present invention, the mother glass has the above-mentioned composition of 97 wt% or more of the composition excluding water, and MoO ₃ and/or WO ₃ is 0.5 to 0. 7.0wt
%, i.e. 0.5 to 7.0wt for 100wt of mother glass
It is starting to be added. The reason is as follows. That is, MoO ₃ and WO ₃ exhibit similar properties and are particularly effective in significantly improving acid resistance. If the addition of one or two of these types is less than 0.5wt%, there will be little effect;
On the other hand, if it exceeds 7.0 wt%, the softening temperature becomes significantly high, which is beyond the purpose of this invention. 0.5~
By adding 7.0 wt%, acid resistance can be further improved without raising the firing temperature. In addition, in this invention, for the mother glass
The addition of 0.5 to 7.0 wt% of MoO ₃ and/or WO ₃ is merely an expression to express the composition ratio; first, a mother glass is made, and then MoO ₃ and WO ₃ are added. It does not have any meaning or content in terms of the manufacturing process. Therefore, all or part of the elements constituting the above-mentioned fluoride may be Mo and/or W. Therefore, in the composition according to the present invention, the elements constituting the fluoride are derived in whole or in part from the elements constituting each of the above-mentioned oxides listed as constituent components of the mother glass, as well as MoO ₃ , WO ₃ is derived from the elements constituting Mo and W, and is usually derived from a combination of both. Next, the raw materials for the low melting point glass composition of the present invention will be explained. The raw materials for the components constituting the low melting point glass composition of this invention include raw materials that produce oxides of the aforementioned components or mixtures of these oxides by firing, or materials that produce fluorides of some of the oxides of the aforementioned components by firing. Any raw material may be used as long as it generates fluorine for the purpose of oxidation. Such materials include, for example, silicic anhydride, sodium carbon, sodium sulfate, sodium chloride, sodium silicate, boric acid, sodium borate, lithium carbonate, zirconium oxide, titanium oxide, zirconium silicate, sodium fluoride, Lithium fluoride, sodium silicate, molybdenum oxide, tungsten oxide,
Calcium carbonate, magnesium carbonate, alumina,
Zinc oxide, strontium carbonate, barium carbonate, etc. are used. Next, a method for producing a transparent low-melting glass composition according to the present invention will be explained. That is,
The low melting point glass composition of this invention is produced as follows. (1) Select appropriate raw materials from the above raw materials, and thoroughly grind and mix them at room temperature, heating if necessary. Of course, the glass may be melted without pulverization and mixing. (2) The above mixture is heated and fired in a furnace to melt and vitrify it. (3) At the final stage of glass melting, 1
Allow to melt for ~4 hours. Stir in between if necessary. (4) In addition, when melting the glass, pre-firing may be performed if necessary. For example, when sodium carbonate and boric acid are used, the raw materials are first thoroughly mixed and reacted at room temperature. At this time, heat if necessary.
Next, the mixture is dehydrated while reacting at 150 to 500°C for 1 to 3 hours. In this way a solid is obtained. Next, crush it. Next, the glass melting described in (3) above is performed. In this way, dehydration and decarbonation hardly occur during glass melting, and therefore no boiling over from the inside of the crucible occurs, which is safe and convenient. (5) In addition to the above, when raw materials containing water, carbonates, or ammonium salts are used, it is preferable to perform pre-calcination as described in (4) above before melting. (6) Either throw the molten glass into water and cool it quickly.
Pour onto a thick iron plate to cool. (7) The obtained glass can be processed by pot mill, vibration mill,
Finely grind it using a grinder. In this way, the desired low melting point glass composition is obtained. Next, the case where a substrate such as a thin iron plate is coated with the glass composition obtained in this manner will be described. That is, in the case of dry glazing, the glass composition is mixed with a pigment, and in the case of wet glazing, pigments, additives such as carboxymethylcellulose, gum arabic, etc. are added as necessary according to conventional methods, and the composition is made into a water-based slip and glazed. However, if necessary, after drying, it is fired at a temperature of 700°C or less. The above explanation describes an example in which an enameled product is manufactured by coating a thin iron plate with the low melting point glass composition of the present invention, but the low melting point glass composition of the present invention can be applied to other materials other than thin iron plates. Of course, it is also possible to coat substrates made of other materials. As described above, since the low melting point glass composition according to the present invention has a low firing temperature of 700°C or less, there is almost no thermal deformation of the thin iron plate when baking it, and the enamel has high dimensional accuracy. They can manufacture products. Moreover, this glass composition makes it possible to form a glassy film that is even more excellent in terms of surface performance, especially acid resistance. Furthermore, since the glass composition of the present invention does not contain harmful or expensive substances, it does not cause problems such as toxicity and is inexpensive. Next, examples will be described together with comparative examples. The raw materials were mixed to have the composition shown in Table 1. Note that Table 1 (Part 1) is based on wt% display, and Table 1 (Part 2) is based on mol% display. In Table 1, the amounts of additives represent the proportion to the mother glass.

【table】

[Table] Next, the above raw material mixture was melted using an alumina crucible in an electric furnace set at 1300°C. The mixture was clarified for about 2 hours, then poured into water, rapidly cooled, and crushed in a pot mill to obtain a low melting point glass composition. The physical properties of the obtained low melting point glass composition were as shown in Table 2. Then, a dispersant and water are added to the obtained glass composition (powdered form) to form a slip, which is coated on a thin iron plate that has been painted and fired with a lower glaze, and then fired under the firing conditions shown in the table to form a glassy product. A film was formed. An enameled product was thus obtained. The performance of the glassy film of the obtained enamel product was as shown in Table 2. The composition of the lower glaze was 20 parts of lower glaze frit #2236 (manufactured by Nippon Fellow Co., Ltd.), 80 parts of #2240, 5 parts of silica, 5 parts of clay, and 0.5 parts of sodium nitrite, and firing was performed at 750°C for 5 minutes.

【table】

〔Effect of the invention〕

Since the low melting point glass composition according to the present invention is configured as described above, a glass film with excellent surface performance can be produced.

[Brief explanation of drawings]

The drawing is an explanatory diagram illustrating the relationship between the firing temperature and the amount of thermal deformation of a thin iron plate.

Claims (1)

[Claims] 1 SiO ₂ ; 52 to 62 wt% B ₂ O ₃ ; 7 to 13 wt% TiO ₂ +ZrO ₂ ; 7 to 14 wt% Na ₂ O + Li ₂ O + K ₂ O; 18 to 26 wt% [However, (TiO ₂ )/(ZrO ₂ ) weight ratio; 1/5 to 2/1 (Na ₂ O)/(Li ₂ O) weight ratio; 1/1 to 5/1 (K ₂ O)/(Na ₂ O) weight ratio ;Over 0 3/1
_A glass _composition consisting of
7.0wt% is added, and part of the above oxide is F ₂
A low melting point glass composition in which only 1.5 to 5.0 wt% of fluoride is substituted. (2) SiO ₂ ; 52 to 62 wt% B ₂ O ₃ ; 7 to 13 wt% TiO ₂ + ZrO ₂ ; 7 to 14 wt% Na ₂ O + Li ₂ O + K ₂ O; 18 to 26 wt% [However, (TiO ₂ )/(ZrO ₂ ) Weight ratio; 1/5 to 2/1 (Na ₂ O)/(Li ₂ O) weight ratio; 1/1 to 5/1 (K ₂ O)/(Na ₂ O) weight ratio; 0 or more 3 /1 or less] MgO, CaO, SrO,
At least one metal oxide selected from the group consisting of BaO, ZnO and Al ₂ O ₃ is added at 0.5 to 5.0 wt%, and MoO ₃ and/or WO ₃ is added at 0.5 wt%.
~7.0wt% is added, and some of the above oxides are
A low melting point glass composition in which 1.5 to 5.0 wt% of _F2 is substituted with fluoride.