JPS5828212B2 - glass parts - Google Patents

Description

[Detailed description of the invention] The present invention relates to a glass composition for coating.

Therefore, the present invention was made for the purpose of producing a coating glass composition that can be fired at a low temperature on a noncombustible substrate that is relatively susceptible to thermal deformation, such as a thin iron plate or a glass plate.

Conventional glass compositions for coating or similar materials include general enamel frits, general low melting point frits, and general sealing glasses.

However, although the frit for enamel has excellent weather resistance, the firing temperature is usually as high as 800 to 850°C, and therefore, when it is coated and fired on glass or thin iron plates, thermal deformation occurs and it cannot be used.

In addition, in the case of iron plates, scale generation occurs due to dust mites and iron oxide, which is a practical disadvantage.

All commercially available low melting point frits contain lead or cadmium oxides or fluorides, and are difficult to use from the viewpoint of toxicity and pollution.

In the case of sealing glass, it is impractical because it contains pollution-related substances and expensive oxides such as thallium and silver.

The present invention has been made based on the above-mentioned circumstances, and the composition expressed in weight range (hereinafter, all terms refer to weight range) is as follows: Si02: 6.0 to 34. O staff B2O3:
18.0-37.5 ratio Al2O3: 7.5-37.5 ratio CaO+Na2O: 20. Li2O/(N
It is characterized in that it is substituted with Li2O at a molar ratio of 115 to 2/3 expressed as (a20+Li2O) (the same applies hereinafter).

The reason why the glass composition according to the present invention is limited to the above range is as follows.

That is, if 5i02 is less than 6.0%, water resistance and chemical resistance will decrease.

Moreover, if it exceeds 34.0%, the softening point will rise and baking will not be possible at low temperatures.

B20. is less than 18.0%, the softening point increases.

If it exceeds 37.5%, water resistance and chemical resistance will deteriorate.

If the diameter of At203 is less than 7.5φ, water resistance and chemical resistance will decrease.

Moreover, if it exceeds 37.5%, the glass will recrystallize and a glossy coating film will not be obtained.

CaO+Na2O+Li2O is equimolar CaO+N
When considered in terms of a 20, if it is less than 20.0%, the softening point will be high, and if it exceeds 40.0%, water resistance and chemical resistance will be poor.

Moreover, the glass crystallizes, making it impossible to obtain a glossy coating.

Moreover, since the expansion coefficient is mostly influenced by CaO+Na2O+Li2O, it becomes too large and unsuitable for coating on glass or iron plates.

The problem here is the blending ratio of Na2O and Li2O.

The larger the ratio of Li2O is, the smaller the expansion rate is, which is advantageous, but the softening point cannot be determined as much.

When a molar ratio of 115 to 2/3 of Na2O is replaced with Li20, a glass having the lowest softening point and good water resistance and chemical resistance can be obtained.

Note that within the above ranges, the following ranges are particularly suitable for glass or iron plates.

1) The preferred range for coating glass is 5in2: 6.0 to 34.0% B20. : 1g, 0-375 da A/203
: 7.5-37.5 poly CaO + Ma2O: 20.0-30.0% Na20 in the glass composition, 115-2/3 molar ratio L
This is the composition range in which i2O is substituted.

This material has a coefficient of thermal expansion of 7.8 to 9.5 (X 10'
/℃), making it suitable for glass coating.

1:) The preferred range for coating iron plates is 5i02: 6.0 to 34. O 俤 B20.
: 18.0-375%A/203 :
7.5~37.5 Poly CaO+Na2O: 30~
This is a composition range in which 40.0% of Na20 in the glass composition is replaced with Li2O at a molar ratio of 115 to 2/3.

This material has a coefficient of thermal expansion of 10.0 to 12.3 (XIO'/
'C) and is suitable for coating iron plates.

Although there are no particular limitations on the raw materials, any materials may be used as long as they can become the oxides listed in the above range or a mixture of these oxides upon firing.

Examples include silicic anhydride, aluminum silicate, boric acid, sodium borate, aluminum hydroxide, aluminum oxide,
Calcium carbonate, calcium hydroxide, sodium carbonate,
These include compounds such as lithium carbonate and lithium hydroxide.

To obtain the desired glass using each of the above-mentioned raw materials, proceed as follows: (a) At room temperature, if necessary, heat and thoroughly grind and mix.Of course, glass melting may be performed without grinding and mixing.

(b) The above mixture is heated and fired in a furnace to melt and vitrify it.

(c) 8oo to 1300℃ in the final stage of glass melting
Melt for 1 to 4 hours.

Stir in between if necessary.

(ii) In addition, when melting the glass, pre-firing may be performed if necessary.

For example, when boric acid, soda carbonate, sodium borate, and aluminum hydroxide are used, the raw materials are first thoroughly mixed and reacted at room temperature.

At this time, heat if necessary.

Next, it 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, when a material containing water such as aluminum hydroxide □, a carbonate, or an ammonium salt is used as a raw material, it is preferable to perform pre-calcination as described above before melting.

(f) Molten glass is either thrown into water to cool it quickly, or poured onto a thick iron plate to cool it.

(G) The obtained glass is finely pulverized using a pot mill, vibrating machine, or grinder, and in the case of dry glazing, it is mixed with pigment, and in the case of wet glazing, according to the usual method, pigment and carboxymethyl cellulose are added as necessary. , gum arabic, and other additives are added to it, and it is made into a water-based slip and glazed, dried if necessary, and then fired.

Although the firing temperature varies depending on the glass composition, a temperature 150 to 200° C. higher than the g-softening temperature is appropriate.

(E) The above composition manufacturing operations are not limited, and may include operations other than those exemplified above, or other incidental operations and auxiliary operations.

For example, when coating on glass, care should be taken to maintain the coating at a maximum temperature of 550 to 600° C. for about 3 to 10 minutes, using slow cooling as a general rule.

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 equal to or higher than the softening point of the frit, and it is also convenient to preheat the frit to a temperature slightly lower than the softening point.

The composition according to the present invention has a firing temperature of 550 to 650°C.
Since the firing cost is low, it can be applied to materials with low heat resistance such as glass and thin iron plates.

Furthermore, since the thermal expansion coefficient is similar to that of glass or iron plate, it has good adhesion.

Furthermore, it has excellent water resistance and chemical resistance.

The composition according to the present invention can also be used as an adhesive for sealing glass and refractories.

Example (I) Raw materials were blended as shown in Table 1.

Note that the unit is parts by weight.

Incidentally, in Table 1, the term "Na2O:Li2O ratio" means the molar ratio.

Note that C and F are comparative examples.

Wholesale The above raw material mixture was heated and dried at 150 to 200°C for 3 hours.

Next, it was coarsely ground and clarified at 1000 to 1200°C for 70 minutes.

The obtained glass was poured onto a thick iron plate, rapidly cooled, and then ground in a bot mill to form a total of 100 meshes.

The physical properties of the obtained glass were as shown in Table 2.

Claims (1)

[Claims] 1 Composition: 5in2: 6.0 to 340 weight φ13
2Q3: 18.0-37.5 weight width At
203: 7.5-37.5 weight ratio Ca
O+Na2O: 20.0 to 40.0 weight range (however, CaO
and Na2O are both >O).
The molar ratio of Li20) is 115 to 2/3 Li2O
A glass composition obtained by replacing with.