JPS6238306B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates primarily to a milky white frit used for dry casting. BACKGROUND ART Conventionally, so-called cast iron enamel, which is a cast iron surface coated with a glass layer, has been widely used as a material for bathtubs, wash basins, sinks, etc. As a raw material for the glass layer of this type of cast iron enamel, a milky white frit containing a zircon component or an antimony component (zircon-based or antimony-based milky white frit) is generally used. In the above-mentioned applications, chemical resistance such as acid resistance and alkali resistance, hot water resistance, and thermal shock resistance are required, and from the viewpoint of appearance, uniform opalescent color development is required. Antimony-based opalescent frit has poor thermal shock resistance and is also inferior in opalescence. If the glass layer is made thicker in order to obtain uniform opalescence, the thermal shock resistance will be even worse. In order to improve these drawbacks of zircon-based or antimony-based milky white frits, a method has also been proposed in which zircon-based or antimony-based milky white frits with different thermal expansion coefficients are prepared and these are used depending on the part of the product. However, it goes without saying that such a method only unnecessarily complicates the manufacturing process. Furthermore, zircon-based opalescent frit has the disadvantage of poor acid resistance and cannot be used with acidic detergents. Titanium component is used to improve the drawbacks of the above-mentioned zircon-based or antimony-based opalescent frits.
A milky white frit containing TiO ₂ (titanium-based milky white frit) has been developed (Japanese Patent Publication No. 31737/1983). Titanium-based opalescent frit has superior opalescence than zircon-based or antimony-based opalescent frit,
Although a product with a uniform opalescent appearance can be obtained, its chemical resistance, hot water resistance, and thermal shock resistance are still unsatisfactory. Therefore, there has been a demand in this industry for the development of an opalescent frit with excellent chemical resistance, hot water resistance, thermal shock resistance, and opalescence properties, that is, excellent overall performance. The present invention aims to meet the above needs. For the above-mentioned purpose, the present inventor paid particular attention to a titanium-based opalescent frit, and conducted extensive research to improve the above-mentioned drawbacks of the frit and completed the present invention. However, the milky white frit of the present invention is
It consists of 100 parts by weight of a component group and 6.0 to 30.0 parts by weight of a second component group, and the first component group is SiO ₂ , ZrO ₂ , TiO ₂ ,
Consisting of B ₂ O ₃ and R ₂ O, SiO ₂ , ZrO ₂ and TiO ₂
and the total amount of ZrO ₂ is 50.0 to 85.0% by weight, and
contains 2.0 _to 15.0 wt%, _TiO2 ranges from 12.0 to 25.0 wt%, _B2O3 ranges from 5.0 to 30.0 wt%, and
R ₂ O is contained in a range of 5.0 to 30.0% by weight, and the second component group includes fluorine components, P ₂ O ₅ , Al ₂ O ₃ , ZnO,
MgO and/or CaO, BaO and/or
SrO, the fluorine component of the second component group is 0.5 to 10.0 parts by weight based on 100 parts by weight of the first component group,
P ₂ O ₅ is 0.5 to 10.0 parts by weight, Al ₂ O ₃ is 5.0 parts by weight or less, ZnO is 10.0 parts by weight or less, MgO and/or
CaO: 5.0 parts by weight or less, BaO and/or SrO
is contained in a range of 10.0 parts by weight or less, and
The total amount of ZnO, MgO, CaO, SrO and BaO is 5.0
520-630 frits in the range of ~25.0 parts by weight
It is characterized by being heat treated at ℃ for 5 to 20 minutes. The invention will be explained in detail below. As mentioned above, the first component is SiO ₂ and 2.0 to 15.0
The total amount by weight of ZrO ₂ and 12.0-25.0 weight % TiO ₂ consists of 50.0-85.0 weight %, B ₂ O ₃ 5.0-30.0 weight %, and R ₂ O 5.0-30.0 weight %. It is. ZrO ₂ is involved in the hot water resistance and acid resistance of the glass layer, so ZrO ₂ is 2% by weight (hereinafter simply %).
If it is less than 15%, the hot water resistance of the resulting product will be significantly inferior, but if it exceeds 15%, the acid resistance will be deteriorated. _TiO2 reduces the opalescence of the glass layer,
It is involved in impact resistance and hot water resistance, and if it is less than 12%, the opalescence and impact resistance will be inferior, but if it exceeds 25%, the hot water resistance will be deteriorated. Furthermore, if the total amount of SiO ₂ , TiO and ZrO ₂ is less than 50%, the acid resistance and hot water resistance will be significantly reduced, and if it exceeds 85%, the frit will become extremely poorly soluble and will lose its practical use. B ₂ O ₃
is responsible for the easy solubility of the frit and therefore B ₂ O ₃
If it is less than 5%, the frit becomes poorly soluble and its opalescence is reduced, but if it exceeds 30%, its hot water resistance and alkali resistance are significantly deteriorated. The second component group includes fluorine components and
It consists of an oxide containing P ₂ O ₅ , and the fluorine component is 0.5 to 10.0 parts by weight per 100 parts by weight of the first component.
It is desirable that the above P ₂ O ₅ is contained in an amount of 0.5 to 10.0 parts by weight. Fluorine compounds and P ₂ O ₅ are involved in thermal shock resistance and whiteness, and if these components are less than 0.5 parts by weight (hereinafter simply referred to as "parts"), it is difficult to obtain good whiteness. Exceeding this will have a negative impact. The second component group preferably contains Al ₂ O ₃ , ZnO, MgO and/or CaO, BaO and/or SrO, these components supplementing the properties of the above essential components, and in particular Al ₂ O ₃ is This is preferable in this respect. In the second component group, for 100 parts of the first component group, Al ₂ O ₃ is 5 parts or less, ZnO is 10.0 parts or less, MgO
and/or CaO is desirably 5 parts or less. If the firing temperature is outside the above range, the glass surface tends to lose its smoothness as the firing temperature increases. Further, the second component group is the first component group 100
If the amount is within the range of 5.0 to 30 parts per part, a desirable result will be obtained for the above-mentioned smoothness. Moreover, if BaO and/or SrO exceeds 10 parts, there will be a tendency to adversely affect hot water resistance and acid resistance. Furthermore, with ZnO
The total amount of MgO, CaO, BaO and SrO is 5.0 to 25.0
It is more desirable for hot water resistance and acid resistance to be within this range. In addition to the above composition, the opalescent frit of the present invention may optionally contain one or more modifiers such as Sb ₂ O ₃ , V ₂ O ₅ , MoO ₃ , and SnO ₂ in an amount of preferably 10% or less.
The content of one or more colorants such as CoO, NiO, MnO, CuO, Fe ₂ O ₃ and Cr ₂ O ₃ is desirably 10% or less, or other subcomponents are added so that the characteristics of the milky white frit of the present invention are lost. It can be added without causing any damage. In the present invention, a milky white frit having the above composition is used.
Heat treatment is performed at 520-630°C for 5-20 minutes. Particles such as ZrO and TiO ₂ that impart opalescence that relatively dissolve in the glassy composition when the glassy composition is fritted from its melting point are called soluble particles. When applied by the method, the degree and speed of nucleation of soluble particles and crystallization vary depending on the location of the base surface due to variations in thermal properties such as temperature, heat capacity, cooling rate, etc. of the base surface, resulting in irregular spots. , resulting in an extremely undesirable appearance with unevenness and the like. Therefore, as described above, by heat treatment at a temperature higher than the nucleation temperature of the soluble particles but lower than the melting point of the frit, at least a part of the soluble particles are precipitated in a crystalline form, and the irregular stains and This prevents the occurrence of unevenness and provides a desirable milky white appearance. Furthermore, such heat treatment improves the flow characteristics of the frit, resulting in an enamel surface with excellent smoothness and gloss. The milky white frit of the present invention thus obtained contains SiO ₂ , ZrO, TiO, B ₂ O ₃ ,
Since it contains RO, fluorine components, and P ₂ O ₅ in the specified ratios mentioned above, it has excellent chemical resistance, hot water resistance,
This provides a product that satisfies both thermal shock resistance and opalescence. Examples Various raw materials were blended and mixed to correspond to the compositions of samples No. 1 to No. 15 in Table 1, which are within the composition range of the frit of the present invention, and melted at 1200 to 1300°C.
Thereafter, it was rapidly cooled to obtain a frit. Similarly,
A comparative frit shown in the same table was obtained. These frits are heat treated at 520-630°C for 5-20 minutes. Place this heat-treated frit on a sieve with 200 meshes (sieve mesh opening 74μ) at a rate of 10 to 20%.
The above frit was sprinkled on a cast iron plate that had been dry-milled to the extent that it remained, sprayed with an underglaze in advance, and fired at 950°C while it was still red hot, and fired in a furnace at 950°C for 50 to 90 seconds to create a test piece. The following performance tests were performed on each of the obtained test pieces and the performances were compared. That is, as performance tests, the following whiteness thermal shock resistance test, acid resistance test, alkali resistance test, and hot water resistance test were conducted. 1 Whiteness [W (Lab)] Whiteness is measured using CDE manufactured by Suga Test Instruments Co., Ltd.
Using SCH-I type, diffuse reflectance L, a, b
The value is measured and substituted into Hunter's whiteness formula to obtain whiteness [W (Lab)]. Measured values are shown as the average value of 5 samples. 2. Thermal Shock Resistance Test The test piece was kept in a warmer at 150°C for 20 minutes, then taken out and immediately placed in water at room temperature (18-20°C). After checking the state of cracks using the red ink penetration method, repeat this operation. The above heating and cooling cycle was repeated 5 times, and those with no cracks were evaluated as good, those with cracks only at the edges were evaluated as fair, and those with cracks on the entire surface were evaluated as poor. 3 Acid resistance test Using a testing device that conforms to the international standard ISO-2733, add 400 ml of a 6% citric acid aqueous solution, hold it in a boiling state for 24 hours, then calculate the weight loss of the enamel layer per unit test surface area, and test three samples. The average value is taken and expressed in g/m ² /day. 4 Hot water resistance test Using a testing device that complies with the international standard ISO-2733, add 400 ml of ion-exchanged pure water and boil it.
After holding for 48 hours, the weight loss of the enamel layer is determined per unit test surface area, averaged over three samples and expressed in g/m ² /day. 5 Alkali resistance test Using a testing device based on the international standard ISO-2734, add 320 ml of 6% sodium pyrophosphate aqueous solution, heat it in constant temperature water at 80°C ± 1°C, hold it for 24 hours, and then measure the weight loss of the enamel layer. It is calculated per unit test surface area, the average value of three samples is taken, and g/
Expressed in m ² /day. The results of the above performance tests are shown in Table 1.

【table】

【table】

[Table] According to the first table, it is clear that _{comparative samples A to C and G to K containing 2% or less of ZrO 2 have} inferior hot water resistance compared to samples No. 1 to No. 15. It is clear that Comparative Sample L containing more than 15% of the acid resistance is inferior to Samples No. 1 to No. 15. Also _TiO2 12
Comparative sample D, which contains less than 25%, is inferior in opalescence and thermal shock resistance compared to samples No. 1 to No. 15, and comparative samples F and H, which contain more than 25%, are inferior to samples No. 1 to No. 15. The hot water resistance is inferior. Furthermore, comparative samples E and F containing 5% or less of B ₂ O ₃ were more difficult to melt than samples No. 1 to No. 15,
Comparative sample M with inferior opalescence and containing more than 30%
The hot water resistance and alkali resistance are significantly inferior to comparative samples No. 1 to No. 15. Thus, samples No. 1 to No. 15 according to the present invention are the first
As shown in the table, it shows excellent performance in all aspects of acid resistance, alkali resistance, hot water resistance, thermal shock resistance, and milky whiteness, completely eliminating the drawbacks of conventional milky white frits of this type. Therefore, the cast enameled bathtubs, cast enameled sinks, etc. related to the frit of the present invention can now be used under harsh conditions that have traditionally been problematic, such as strong acidic detergents and strong alkaline bath additives. Because the opalescence is extremely excellent, it is sufficient to use approximately half the amount of conventional zircon-based or antimony-based frits, and in this way, the amount of glaze used can be greatly reduced, and the amount used can also be reduced. brings about further improvement in thermal shock resistance. The frit of the present invention can be applied to the parts of the product,
For example, there is no need for complicated methods such as using different types of glazes for the upper edge and inner surface of the sink; just one type of frit can be applied to any part of the product, simplifying the manufacturing process. It is also a major rationalization.

Claims (1)

[Claims] 1. 100 parts by weight of the first component group and 6.0 to 6.0 parts by weight of the second component group.
30.0 parts by weight, and the first component group is SiO ₂ ;
Consisting of ZrO ₂ , TiO ₂ , B ₂ O ₃ , and R ₂ O, SiO ₂
and the total amount of ZrO ₂ and TiO ₂ is 50.0 to 85.0% by weight, and ZrO ₂ is 2.0 to 15.0% by weight, and TiO ₂ is 12.0 to 85.0% by weight.
_B2O3 is contained in a range of 25.0% by weight, _B2O3 is contained in a range of 5.0 to 30.0% by weight, and _R2O is contained in a range of 5.0 to 30.0% by weight, and the second component group is a fluorine component, _{P2 O5} ,
It consists of Al ₂ O ₃ , ZnO, MgO and/or CaO, BaO and/or SrO, and the fluorine component of the second component group is 0.5 to 100 parts by weight of the first component group.
10.0 parts by weight _{, P2O5} is 0.5-10.0 parts by weight, _{Al2O3 is}
5.0 parts by weight or less, ZnO is contained in a range of 10.0 parts by weight or less, MgO and/or CaO is contained in a range of 5.0 parts by weight or less, BaO and/or SrO is contained in a range of 10.0 parts by weight or less, and ZnO, MgO, CaO, and SrO are A milky white frit for dry casting, characterized in that the frit containing BaO in a total amount within the range of 5.0 to 25.0 parts by weight is heat-treated at 520 to 630°C for 5 to 20 minutes. 2. The opalescent frit for dry casting according to claim 1, which contains a modifier such as an opacifying agent and a surface strength regulator, and a sub-component such as a coloring agent.