JPS6120495B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a glass composition for coating on substrates such as thin iron plates, aluminum plates, glass plates, noncombustible substrates, etc., which can be fired at low temperatures. Conventionally, as a glass composition for coating,
For example, hollow frits for iron plates and general low melting point frits are known. However, these have various drawbacks. In other words, hollow frits for iron plates generally have a high firing temperature (800°C).
~850℃), and the lowest temperature was around 750℃.
Therefore, it could not be applied to thin iron plates. This is because such a substrate is thermally deformed at the enamel firing temperature. Furthermore, due to the high temperature firing, a large amount of hydrogen gas produced by the reaction between iron and water is absorbed by the iron plate, which is also a cause of the tendency for splatter to occur. On the other hand, general low melting point frits are lead,
Since it contains cadmium or fluoride, it is toxic and has the disadvantage that it is difficult to dispose of the waste that is discarded during the manufacturing process. In addition to the above, general sealing glasses are also known, but they are also expensive because they contain toxic substances and use expensive metals such as thallium and silver. It is therefore an object of this invention to provide a non-toxic, inexpensive glass composition that can be fired at low temperatures onto a substrate. In summary, the glass composition of the present invention has the following composition by weight: 6.0≦Sio ₂ ≦26.0 14.0≦B ₂ O ₃ ≦35.0 17.0≦Al ₂ O ₃ ≦35.0 15.0≦CaO+R ₂ O≦30.0 0≦SnO ₂ ≦15.5 0≦TiO ₂ ≦15.0 0≦ZrO ₂ ≦15.0 However, 2≦SnO ₂ +TiO ₂ +ZrO ₂ ≦25.0 R ₂ O is at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O At least part of the CaO in the mother glass composition consisting of two oxides is replaced with an oxide consisting of at least one of BaO, ZnO, SrO, and MgO, and the CaO portion is replaced by an equimolar amount of a straight line connecting the following four points. The molar ratio is selected within the range enclosed by . a: (BaO and/or SrO: CaO and/or MgO: ZnO = 3:97:0) b: (BaO and/or SrO: CaO and/or MgO: ZnO = 0:97:3) c: (BaO and/or SrO:CaO and/or MgO:ZnO=100:0:0) d: (BaO and/or SrO:CaO and/or MgO:ZnO=0:0:100) These ranges are indicated by the triangles in the attached diagram. It is represented in the phase diagram. The reason why the glass composition according to the present invention is limited to the above composition range is as follows. That is, if SiO ₂ is less than 6.0%, the water resistance and chemical resistance of the glass composition will be low, and particularly the alkali resistance will be low. Moreover, if it exceeds 26.0%, the softening temperature will become high and low-temperature firing will not be possible. When B ₂ O ₃ is less than 14.0%, the softening temperature becomes high, and when it exceeds 40.0%, water resistance and chemical resistance deteriorate. If Al ₂ O ₃ is less than 17.0%, water resistance and chemical resistance will be low, particularly acid resistance will be low. Moreover, when it exceeds 42.0%, the softening temperature increases. When CaO+R ₂ O is less than 15.0%, the softening temperature becomes high, and when it exceeds 40.0%, water resistance and chemical resistance decrease. When CaO + R ₂ O is selected within the above range, the coefficient of thermal expansion of the glass composition is 8.0.
×10 ⁻⁶ to 12.0×10 ⁻⁶ , making it ideal for coating glass compositions for glass and iron plates. Especially CaO+
When Na ₂ O is selected as 30.0<CaO+R ₂ O≦40.0,
The coefficient of thermal expansion of the glass composition is 12.0×10 ^-6 ~13.5×
10 ^-6 , making it ideal for steel plates and aluminum plates. Further, SnO ₂ , TiO ₂ , and ZrO ₂ each improve chemical resistance and are necessary when producing a milky white glass composition. That is, SnO ₂ ,
The addition of TiO ₂ and ZrO ₂ significantly increases the alkali resistance, respectively. Addition of TiO ₂ and ZrO ₂ is particularly effective for acid resistance. These additives need to be added in a total amount of 2.0% or more in order to improve chemical resistance. Especially when increasing the milky whiteness,
It is necessary to further increase the amount of these additions.
However, if the total amount of these additives exceeds 25.0%, the softening temperature will rise too much and the melting point will not be lowered. With the above component system, a glass composition with a firing temperature of 530 to 650°C can be obtained.
By substituting with an oxide consisting of at least one of MgO, BaO, SrO, and ZnO, the resulting mixing effect further lowers the firing temperature.
If we express this in general numbers, it would be a decrease of 2 to 15%. In addition, in this composition range, CaO and MgO and BaO and SrO have a softening temperature lowering effect, water resistance,
It was found that each had similar effects on chemical resistance. Therefore, the expressions CaO and/or MgO, and BaO and/or SrO are used. Next, the raw materials for the glass composition of this invention will be explained. In principle, the raw material used in this invention can be used as long as it is an oxide having the above-mentioned composition or a mixture of these oxides by firing. For example, silicic anhydride, aluminum silicate, sodium sulfate, sodium chloride, soda carbonate, sodium silicate, boric acid, sodium borate, aluminum hydroxide, aluminum oxide, lithium carbonate, sodium carbonate, lithium hydroxide, potassium carbonate, Tin oxide, titanium oxide, zirconium oxide, sodium bicarbonate, calcium carbonate, calcium hydroxide, magnesium carbonate, barium carbonate, strontium carbonate, zinc oxide, magnesium chloride, magnesium oxide, magnesium hydroxide, magnesium sulfate, strontium sulfate, strontium oxide , barium sulfate, barium hydroxide, barium carbonate, etc. Next, a method for manufacturing the glass composition of the present invention will be explained. That is, the glass composition is manufactured as follows. (b) Select appropriate raw materials from the raw materials listed above, and grind and mix thoroughly at room temperature, heating if necessary. Of course, the glass may be melted without pulverization and mixing. (b) The above mixture is heated and fired in a furnace to melt and vitrify it. (c) At the final stage of glass melting, 1
Allow to melt for ~4 hours. Stir in between if necessary. (d) In addition, when melting the glass, pre-firing may be performed if necessary. For example, when using phosphoric acid, soda carbonate, boric acid, and zinc oxide, 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, (c) glass melting is performed. This method is safe and convenient since almost no dehydration or decarbonization occurs during glass melting, and no boiling over from the inside of the crucible occurs. (e) In addition to the above, if raw materials containing water such as dibasic sodium phosphate, dibasic zinc phosphate, zinc carbonate, ammonium phosphate, etc., or carbonates or ammonium salts are used, before melting. It is preferable to perform the pre-firing described in (d) above. As described above, the desired glass composition is obtained by heating and firing the raw materials in a furnace to melt and vitrify them. Next, the case where the glass composition thus obtained is applied to a base material and fired will be described. That is, the molten glass composition obtained as described above is poured into water to be rapidly cooled, or poured onto a thick iron plate to be cooled. Next, this is pulverized using a pot mill, vibration mill, sieve machine, etc. Next, the glass composition fine powder is applied to a base material and fired. In this case, when performing dry glazing, the glass composition fine powder is mixed with pigment, and when wet glazing, additives such as pigment, carboxymethylcellulose, and gum arabic are added as necessary according to conventional methods, and a water-based slip is prepared. It is then glazed, dried if necessary, and then fired. The firing temperature varies depending on the glass composition, but is approximately 150 to 200 degrees higher than the softening temperature.
℃ higher temperature is suitable. In these cases, operations other than those exemplified above or other incidental operations may be included. For example, when coating on glass, use slow cooling as a general rule, and use a maximum temperature of 500 to 600℃ for 30 minutes.
Care should be taken to hold the sample for about 10 minutes. Alternatively, a fluidized dipping method may be used for coating the frit powder. In that case, it is necessary to preheat the base material to be coated to a temperature above the softening point of the frit, and it is also convenient to preheat the frit to a temperature slightly lower than the softening point. As described above, the composition of the present invention has a low firing temperature of 500 to 630°C, so the firing cost is low, and it can be applied to materials with low heat resistance such as glass and thin iron plates, and can be applied to materials with low heat resistance such as glass and thin iron plates. It is also possible to prevent the occurrence of black spots caused by high-temperature firing. Furthermore, since the coefficient of thermal expansion is similar to that of glass or iron plate, it has good adhesion. It also has excellent water resistance, chemical resistance, and weather resistance. Furthermore, since it does not contain harmful or expensive substances, it does not pose any toxicity problems and is inexpensive. Next, examples will be described. Example () Raw materials were blended as shown in Table 1. In the table, A, B are comparative examples of C, D, E, F are comparative examples of G, H, I, J are K, L,
Comparative example of M, N is O, comparative example of P, Q is R, S
This is a comparative example (the same applies to the table below). In addition,
The unit is parts by weight.

[Table] () Glass melting method The above raw material mixture was heated and dried at 150 to 200°C for 3 hours. Next, coarsely grind and heat at 1000 to 1200℃.
Cleared for 70 minutes. The glass composition thus obtained was poured onto a thick iron plate, rapidly cooled, and then ground in a pot mill to form 100 meshes.
The physical properties of the obtained glass composition fine powder were as shown in Table 2.

[Table] The method for measuring physical properties is as follows. (1) Thermal expansion coefficient and softening temperature A rod-shaped glass sample with a diameter of approximately 3 mm and a heating rate of approximately
Expansion was measured by a displacement meter at 20°C. The softening temperature was determined from the recording paper at the point at which the glass changes from expansion to contraction due to deformation. (2) Boiling loss Adjust the particle size of the glass to 32 mesh to 60 mesh, accurately weigh 3 g, put it in a 300 cc eggplant flask with 50 cc of hot water, and boil for 60 minutes while refluxing. The boiled sample was passed through a 1G3 glass filter, and the weight loss before and after boiling was determined to determine the weight loss, which was expressed as a percentage of the weight before boiling. (3) Acid resistance weight loss value: Put 2000g of glass powder with a particle size of 32 mesh to 60 mesh into a 100cc beaker.
5g/100c.c. citric acid aqueous solution (30℃) 50c.c.
After stirring with a stirrer at room temperature for 15 minutes, the mixture was suctioned through a 1G1 filter and the residue was weighed to calculate the acid resistance loss value. Acid resistance weight loss value = (1-residue/2000) x 100 (%) (4) Alkali resistance weight loss value Put 2000g of glass powder with a uniform particle size of 32 mesh to 60 mesh into a 100 c.c. beaker.
After stirring with a stirrer for 15 minutes at room temperature with 50 c.c. of a 1N-NaOH aqueous solution (30°C), the alkali resistance weight loss value was calculated by suctioning through a 1G1 filter and weighing the residue. Alkali resistance weight loss value = (1-residue/2000) x 100 (
%) () Method of coating glass and iron plates and its results The glass composition fine powder prepared by the above method was dispersed in a 1% aqueous sodium borate solution containing 2% methylcellulose, formed into a slip, and sprayed. Painted on glass plates and iron plates.
After drying, the result was fired under the firing conditions shown in Table 3.
Table 3 summarizes the performance of the glass composition coating formed on the substrate.

[Table] In Table 3, each substrate used was a polished plate that had only been subjected to degreasing treatment. The firing conditions were slow heating and slow cooling, and firing was performed such that the temperature shown in Table 3 was the maximum temperature. The performance tests shown in Table 3 were conducted as follows. (1) Thermal shock test: A 10 cm x 10 cm sample was placed in a dryer kept at a predetermined temperature, left for 30 minutes, and then placed in cold water at room temperature to check for cracks and peeling. The maximum temperature at which no abnormality occurs in the sample is indicated. (2) Boiling test: A 10cm x 10cm sample was immersed in boiling water for 5 hours, and changes in appearance were checked. (3) Acid resistance: 3cm impregnated with 3% acetic acid aqueous solution
Layer three pieces of 3cm square filter paper on top of the sample, cover with a watch glass, and leave for 15 minutes.
The filter paper was removed, washed with water, and dried. Then, changes in the surface condition were observed. (4) Alkali resistance: Place three 3cm x 3cm square filter papers impregnated with 10gr/100c.c. Na ₂ CO ₃ aqueous solution over the sample, cover with a watch glass and leave for 15 minutes. Remove the filter paper, wash it with water,
Dry. Then, changes in the surface condition were observed.

[Brief explanation of the drawing]

The drawing is a triangular phase diagram illustrating the composition range of the glass composition of the present invention.

Claims (1)

[Claims] 1 Composition expressed in weight% is 6.0≦Sio ₂ ≦26.0 14.0≦B ₂ O ₃ ≦35.0 17.0≦Al ₂ O ₃ ≦35.0 15.0≦CaO+R ₂ O≦30.0 0≦SnO ₂ ≦15.5 0≦ TiO ₂ ≦15.0 0≦ZrO ₂ ≦15.0 However, 2≦SnO ₂ +TiO ₂ +ZrO ₂ ≦25.0 R ₂ O consists of at least one oxide selected from the group consisting of Li ₂ O, Na ₂ O and K ₂ O At least part of the CaO in the mother glass composition is replaced with an oxide consisting of at least one of BaO, ZnO, SrO, and MgO, and the CaO part is replaced by an equimolar amount within the range surrounded by a straight line connecting the following four points. A glass composition characterized by having a molar ratio of a: (BaO and/or SrO: CaO and/or MgO: ZnO = 3:97:0) b: (BaO and/or SrO: CaO and/or MgO: ZnO = 0:97:3) c: (BaO and/or SrO:CaO and/or MgO:ZnO=100:0:0) d: (BaO and/or SrO:CaO and/or MgO:ZnO=0:0:100) 2 CaO+R in the mother glass composition 2. The glass composition according to claim 1, wherein ₂ O is selected such that 30.0<CaO+R ₂ O≦40.0.