JPS60251148A - Frit composition - Google Patents

Abstract

PURPOSE:To obtain a frit composition for enamel giving cover coat enamel which can be baked at a low temp. without producing a baking strain and does not cause reboiling even when applied to ground coat enamel baked at a low temp., by adding MoO3 to borosilicate base glass having a specified composition. CONSTITUTION:Frit is obtd. by adding 0.1-5wt% MoO3 to borosilicate base glass having a composition consisting of 56-63% SiO2, 6-10% B2O3, 5-10% RO2 [R is Ti+Zr (Ti/Zr=1/3-3)], 23-26% R'2O [R' is Na+Li (Na/Li=2/3-4)] and 3-7% F2, and the frit is blended with bentonite, corpuscular silicic acid, sodium silicofluoride, potassium chloride, a pigment, etc. to prepare cover coat enamel. When this cover coat enamel is sprayed on a steel sheet coated with ground coat enamel, dried, and baked at about 720 deg.C, an enameled surface of high quality is obtd.

Description

[Detailed description of the invention] 〔Technical field〕 This invention belongs to the field of manufacturing technology for enamel products.

[Background technology]

Conventional enamel frits are baked onto the substrate at 800 to 850°C, and can form a glassy film with excellent surface properties (acid resistance, alkali resistance, boiling resistance, weather resistance, etc.) on the substrate. It is something. However, since the firing temperature is quite high, when baking into a noodle cutting iron plate, etc., the amount of thermal deformation of the thin iron plate increases, and the dimensional accuracy of the resulting enameled product deteriorates. In order to solve this problem, it has been considered to use a glass frit with a low melting point as a frit for enamel.

In order to meet the above demands, the present inventors have proposed a so-called low-temperature glaze composition in Japanese Patent Application No. 54-99761.

However, even if the above-mentioned low-temperature glaze composition is applied (at 700 to 750°C) on top of a normal high-temperature fired lower glaze, the characteristics of the above-mentioned composition cannot always be fully exhibited.

Therefore, the lower glaze also needs to be fired at a low temperature.

A lower glaze composition that can be fired at low temperatures can be achieved, for example, by modifying the borosilicate glass composition.

However, when the lower glaze is applied to the substrate (iron plate) by low-temperature firing,
When a low-temperature top glaze is applied on top of the glaze, a new drawback arises: reboiling (the bottom glaze comes out to the top).

[Purpose of the invention]

To provide an upper glaze for low-temperature firing that does not cause reboiling even when an upper glaze is applied to a lower glaze at a low temperature.

Another object of the present invention is to provide a glazing technique that does not cause firing distortion.

[Disclosure of the Invention] Considering the causes of reboiling, the first reason is that the lower glaze is too soft during firing of the upper glaze. This agrees well with the fact that reboiling does not occur when a low-temperature transparent glaze is coated on top of a high-temperature lower glaze. However, when considering low-temperature firing, the lower glaze must be softened to a certain extent or it will have poor adhesion to the iron plate, which is the next drawback.

Furthermore, the present inventors are aware of the fact that even if the same lower glaze is used, a milky white upper glaze is less likely to cause boiling. On the other hand, there is also the fact that reboiling is more likely to occur in the case of transparent top glazes. Therefore, as a result of particularly examining the composition of the transparent top glaze, it was discovered that reboiling could be improved by adding MQ 08, and the present invention was achieved.

The characteristics of the present invention are 56.0≦5in2≦63.0 6・0≦B2O3≦10.0 5, Q:<RO2≦10.0 (iL-Ti +Zr
)23.0≦'20≦26.0 (R4 + Li
)3≦F2≦7゜l/8≦”13r≦3.0 2A≦Nν11≦40 0.1 to 5.0% by weight of Mo0g is added to the mother glass.Details will be given below based on examples. explain.

Example 1 [Manufacture of top glaze] (Creation of top glaze) R2240 (manufactured by Nippon Ferro Co., Ltd.) 100 parts by weight No. 9 clay 7 Silica stone 5 Hydrous borax 0.5" Sodium nitrite 0.05" Water 50〃 The grain size at the time when milling was carried out with a bot mill using the above composition was C5.89/#200.50cc slip] @ (top glaze coating) A steel plate for enameling pretreated by a conventional method (thickness 1.6
The top glaze was sprayed onto the top of the top (m) to a thickness of about 150 μm, dried at 150° C. for 20 minutes, and then fired at 750° C. for 6 minutes to coat the top glaze.

(Creating top glaze) Frit B Zoo Juyaribe Bentonite 0,4 Fine particle silicic acid 1.0 Soda silica 0.1 Potassium chloride 0.4 parts by weight Face pigment 4.5 + water 50 The above formulation was milled using a pot mill.

The grain resistance at that time is CI 2.19/# 200.5Qcc
It was a slip.

The frit used was prepared according to the formulation shown in Table 1 and according to the method disclosed in Machichi No. 54-997ei1.

(Coating of top glaze) Approximately 1 coat of the above top glaze is applied on the top glaze coated steel plate.
50μ l! After spray painting on tjL, about 150
The roots were dried at ℃ for 20 minutes. Next, the material was fired at 720° C. for 6 minutes to prepare a powder plate. No distortion occurred in the enamel.

Its surface performance is J
Both acid resistance and alkali resistance according to IS (R4301) 2 were AA class.

Example 2 The preparation and coating of the top glaze were carried out in the same building as in Example 1. In addition, the top glaze was created using Fritto C (Table 1) according to Example 1.
Milling was done using the top glaze mixture. Particle size is CZ6V
#200.5Qcc slip].

As in Example 1, it was sprayed to a thickness of 150 μm and dried and fired. The obtained enamel had no distortion, the surface of the enamel had no defects such as boiling in appearance, and both acid resistance and alkali resistance (JIS K2SO3) were grade AA.

Comparative Example The same procedure as in Example 2 was conducted using frit A (Table 1). The same top glaze as in Example 1 was used, and the particle size of the top glaze was C2.
, 59/#200.5 Q cc slip.

On the enamel side, so-called reboil had occurred, with many black spots of the upper glaze rising up on the upper glaze layer.

Example 3 A steel plate coated with the same top glaze as in Example 1 was spray coated with the milky white top glaze shown below.

1553 manufactured by Nippon Ferro Co., Ltd. as a milky white upper glaze frit
B was used and the formulation was the same as the upper glaze formulation in Example 1 (however, the pigment was changed to 1.8). The particle size at that time is [2,
3y/$200, 50cc slip].

15 (After drying for 1 and 20 minutes, baking was performed at 740°C for 6 minutes to provide a pastel-like color layer. On top of that, a transparent top glaze containing 0 pigment of Example 1 [particle size 2° 8f/# 200.5
0CC slip] was applied to a thickness of 80μ, and the coating was carried out under the same drying and firing conditions as in Example 1. No distortion was observed in the obtained enamel.

The enamel surface had no defects such as reboiling as in Example 1, and its acid resistance and alkali resistance were AA class.

〔Effect of the invention〕

This invention has the following characteristics: 56.0≦S i 02≦63.0 6.0 ≦B2O3≦1O10 5,0≦RO2≦10.0 (R=Ti+Zr)23,
O≦R/g O≦26.0 (R' trigram λ+Li)3 ≦F
2 ≦7゜1/B ≦TVl-T≦3.0 2/8 ≦Na/Li≦4.0 Since 0.1 to 5.0 weight percent of M2O3 was added to the mother glass, firing at low temperature was possible. It was possible to provide a top glaze without distortion and without reboiling.

patent applicant Matsushita Electric Works Co., Ltd. Representative Patent Attorney Toshimaru Takemoto (2 idiots)

Claims (1)

[Claims] (1) The glass composition is: 56.0≦5i02≦63.0 6.0≦B2O3≦10.0 5.0≦R02≦I Q, Q (L=Ti + Zr)
23.0≦R20≦26.0 (R'-Frozen Li)3≦
A frit composition for enamel having a glass composition in which 0.1 to 5.031 amounts of Mo0g are added to a mother glass such that F2≦7゜Koma≦Ti/Zr≦3,0 F≦NVLi≦40.