JPH07115884B2 - Enamel frit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field This invention relates to enamel frits.

(Prior Art) Conventionally, as a enamel layer that covers the surface of a base material such as iron, aluminum, and stainless, a glossy glossy material has been generally used, but recently, a enamel panel for building materials, a signboard, and a display. For boards, blackboards, whiteboards (marker boards) and the like, matte enamel layers with low gloss have often been required.

Various methods have been tried as methods for obtaining the matt enamel layer in a matte state, but there are many problems.

That is, SiO ₂ , Al ₂ O ₃ and TiO ₂ are added to ordinary enamel frit.
The method of adding a large amount of high melting point materials such as, and baking at a temperature below the melting point of these materials has the problem that the surface of the enamel layer is rough, stain resistance and corrosion resistance are poor, and uneven glossing occurs due to variations in baking temperature. There is. In addition, a method of precipitating crystals such as silicate by adding a large amount of alkali or boric acid to the low melting point frit containing a large amount of lead used in aluminum enamel is the roughness of the enamel layer and the hairline due to the difference in thermal expansion coefficient. The appearance is inferior due to the occurrence of cracks and cracks, and only inferior chemical resistance, stain resistance, water resistance and weather resistance can be obtained. Furthermore, SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂
There is also a method of spraying a high melting point material such as, for example, on a glossy enamel layer having ordinary gloss by plasma spraying,
Roughness of the surface is likely to occur and there is a problem in terms of stain resistance.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned conventional problems, and it is possible to form any enamel layer of both glossy and matty depending on the temperature range of the firing temperature, And the resulting glossy and matty enamel layers have excellent surface smoothness, acid resistance, stain resistance, weather resistance, etc., and are not affected by variations in firing temperature within the firing temperature range of glossy and matte materials. It is an object of the present invention to provide an enamel frit capable of forming a glossy or matte enamel layer having a uniform and good appearance.

(Means for Solving Problems) However, the enamel frit of the present invention is composed of SiO ₂ and TiO ₂ .
The total amount of ZrO ₂ is 40 to 65% by weight, two or more kinds containing at least Li ₂ O among Na ₂ O, K ₂ O and Li ₂ O are 10 to 25% by weight, ZnO, MgO, Ba
2 or more of O and CaO containing at least BaO and ZnO is 4 to 2
6 wt%, B ₂ O _3, Al ₂ O _3, Sb 5 to 20% by weight of one or more of which contains at least B ₂ O ₃ of ₂ O _3, at least P ₂ O of P ₂ O ₅ and MoO ₃ Containing 0.5 to 6.5% by weight of one or more types including ₅ ,
And the content ratio of each of the above components, SiO ₂ is 18 to 42 wt%, Ti
O ₂ is 14 to 28 wt%, ZrO ₂ is 1 to 4 wt%, Li ₂ O is 2 to 6
% By weight, 0 to 11% by weight of Na ₂ O, 0 to 12% by weight of K ₂ O, ZnO
1.5-10% by weight, BaO 1.5-10% by weight, MgO 0-5% by weight, CaO 0-8% by weight, B ₂ O ₃ 5-13% by weight, Al ₂ O ₃
Is 0 to 4% by weight, Sb ₂ O ₃ is 0 to 3% by weight, and P ₂ O ₅ is 0.5 to 2.
5 wt%, MoO ₃ 0-4 wt%, SiO ₂ / Ti
Enamel frit having an O ₂ value in the range of 65/35 to 40/60.

In the present invention, each constituent component of the enamel frit is limited based on the knowledge obtained by the inventor as a result of the research. The reason for the limitation will be described below.

First, SiO ₂ , TiO ₂ , and ZrO ₂ (hereinafter collectively referred to as RO ₂ group) are essential components for crystallization and improving the durability of enamel, and the total amount of RO ₂ group in the enamel frit is 4%.
If it is less than 0% (% by weight, the same applies hereinafter), the durability, acid resistance and matt state of the surface of the enamel layer after firing will be poor, and if it exceeds 65%, the temperature at which the crystallization will become matte due to crystallization will occur. Higher, lowering productivity and product quality. For each component, if the SiO ₂ content is less than 18%, the durability and acid resistance of the enamel layer will deteriorate, and if it exceeds 42%, the matting temperature will be too high. Further, if TiO ₂ is less than 14%, crystallization is poor, and if it exceeds 28%, the firing temperature becomes high and the adhesiveness also deteriorates. To limit the mutual proportions SiO ₂ / TiO ₂ of SiO ₂ and TiO ₂ are mat for the Furitsuto of the present invention, to obtain a normal firing range for obtaining the gloss quality enamel layer, the crystallization mat substance enamel layer Produces both firing zones of the qualitative firing zone,
The purpose is to impart a property that can be used for both glossy and matte materials, and when the mutual ratio is greater than 65/35, it is difficult to make matte material, and even if matte material is used, the required firing temperature is extremely high. At high temperatures, the quality of the matte, the surface smoothness, and the uniformity of the color development will be lacking. On the other hand, if the mutual ratio is less than 40/60, it becomes difficult to vitrify into enamel during firing and the adhesion is deteriorated, which is not preferable. With respect to ZrO ₂ , if the content is less than 1%, the durability and acid resistance of the enamel layer are poor, and if it exceeds 4%, it becomes difficult to uniformly dissolve in the frit due to the relationship with other components, and the time required for melting Is required, and the acid resistance is lowered and the matting temperature is soared, which is not preferable.

Next, the total amount of Na ₂ O, K ₂ O, Li ₂ O (hereinafter collectively referred to as the R ₂ O group) was adjusted to 10
The reason for limiting the content to 25% by weight is to obtain the coefficient of thermal expansion of the enamel layer suitable for the enamel substrate other than the aluminum enamel substrate having a large coefficient of thermal expansion. It is necessary to mix the substances, and in this case, the durability and acid resistance of the enamel layer are markedly reduced, and it is difficult to form a matte material that is uniform in color and smooth at normal firing temperatures. The coefficient becomes too large, resulting in appearance defects such as hair lines, fine bubbles, discoloration, and deterioration of durability. In addition, the reason why Li ₂ O is an essential component in the R ₂ O group is to promote uniform milky white crystallization at a firing temperature lower than that of TiO ₂ , and if the Li ₂ O content is less than 2%, the enamel layer Becomes bluish and uneven milky white, and the acid resistance is lowered, and if it exceeds 6%, the surface of the matte enamel layer becomes rough, and the acid resistance, stain resistance and weather resistance are deteriorated. The coefficient of thermal expansion becomes too large and enamel defects easily occur.

If the total amount of ZnO, MgO, BaO, CaO (hereinafter collectively referred to as RO group) is less than 4%, the acid resistance and weather resistance are deteriorated. If the total amount exceeds 26%, the frit has a high melting point and the mat is under-baked. It is not preferable because only a high quality surface can be obtained and poor adhesion occurs. Also, limiting ZnO and BaO to 1.5-10% respectively,
This is to maintain the acid resistance and durability of enamel and to form a uniform and milky matty enamel layer at lower temperatures. On the other hand, MgO and CaO are selected according to the coefficient of thermal expansion of the metal base, and when the upper limit of each component is exceeded, the melting point increases and the appearance of the enamel layer does not show a fresh milky white, and when MgO is excessively added. Causes a problem that it tends to be bluish, and when CaO is excessively added, it becomes a light brown emulsion mat.

Next, the total amount of B ₂ O ₃ , Al ₂ O ₃ and Sb ₂ O ₃ (hereinafter collectively referred to as the R ₂ O ₃ group) is set to 5 to 20% in order to match the thermal expansion of the enamel layer and the enamel substrate. And, the purpose is to maintain durability and acid resistance. If the content of the essential component B ₂ O ₃ is less than 5%, the frit has a high melting point and a high thermal expansion and the enamel appearance is deteriorated, and if it exceeds 13%, the acid resistance, weather resistance, stain resistance, etc. The decrease is significant. Al ₂ O ₃ , Sb ₂ O ₃
Is preferably added together with B ₂ O _{3 from} the viewpoint of improving the appearance of enamel and maintaining acid resistance.

As another component, P ₂ O ₅ has a function of forming an emulsion-colored matte surface with a small amount, but when added in excess of 2.5%, fine bubbles are easily formed on the surface of the enamel layer, and it is normal. It is difficult to print. Addition of MoO ₃ smoothes the surface of the enamel layer and improves acid resistance, durability, and stain resistance. However, addition of more than 4% conversely causes the enamel to have a high melting point and cause insufficient baking, resulting in poor adhesion. Is not preferable.

(Function) In the enamel frit of the present invention, the melting point thereof is adjusted by the combination of the above-mentioned respective component ratios, and 620 to 740 ° C.
It melts and vitrifies at the firing temperature of to form a glossy enamel layer. Further heating above this melting point cuts off the oxygen supply from the vitrified enamel surface, and Sb ₂ O ₃ , Li ₂ O, P ₂ O ₅ etc. become nuclei in the enamel layer and become T.
Precipitation of i-crystals starts, the surface of the enamel layer is roughened with the growth of i-crystals, oxygen supply is restarted, and a sinter is formed to form a depleted matte state. The baking temperature for this matte treatment is 700 depending on the combination of the above-mentioned component ratios.
At 850 ° C, a matte enamel layer with a uniform and smooth surface is formed.

(Examples) Examples and comparative examples of the present invention will be described below.

As the flits, flit Nos. 1 to 1 having the composition shown in Table 1 are used.
As a comparative example, a frit No. 29 to 33 in which the frit component limited range of the present invention is partially exceeded as a comparative example, a leaded frit No. 34 for aluminum containing 26% of PbO instead of CaO, and Li
A conventional titanium emulsion frit No. 35 for iron enamel containing 4% of fluorine instead of ₂ O was used.

As a glaze for baking enamels, frit No. 1-35
To 100 parts of each frit, 0.2 parts of potassium carbonate, 0.5 parts of commercially available car plex (high SiO ₂ powder), and 0.2 parts of boric acid were added so as to hardly affect the characteristics of the frit, and the mixture was doubled with 45 cc of water. Alumina boulder 1.5kg in 300g pot mill
It was put together with the above, crushed for 3 hours, and all-passed through a 100 mesh sieve to give glaze Nos. 1 to 35, respectively. Further, the same additives as above and 100 parts of the frit and 40 parts of silica stone powder were added to the frit No. 35, and the mixture was crushed and ground in the same manner as the above to obtain a glaze No. 36.

Next, using each of the above glazes, a enamel plate made by baking iron enamel black bottom glaze on a 20 cm square 1 mm thick steel plate is placed on a enamel plate with eight 3 cm square windows and spraying is performed while repeating masking. 620 to obtain a glossy enameled layer
For the first time, the firing temperature is changed from ℃ to 740 ℃ every 30 ℃, and in order to obtain a matte enamel layer, a test piece that has been glazed in the same manner is heated in the range of 700 ℃ to 850 ℃, and the firing temperature is changed by 30 ℃. Table 2 shows the firing temperature and the characteristics of the enamel layer for the ones which were fired to obtain the best appearance of the enamel layer.

In addition to the above test, glaze Nos. 8 and 9 were used to examine the influence of the substrate to be glazed.
The aluminum plated steel sheet of No. 10 is heated at 750 ° C for 5 minutes to apply glaze to an Al-Fe alloyed substrate, and using glaze No.10, a substrate made of SUS-430 stainless steel sheet of 10 cm square and 1 mm thick When the former was baked at 770 ° C. and the latter was baked at 840 ° C., a matte enamel layer having the same appearance as that baked on the iron enamel black bottom glaze base could be obtained.

The contents of the characteristic test shown in Table 2 are as follows.

(A) Appearance The baking appearance of enamel is judged by the naked eye, and the judgment categories are as follows.

◎ = Good without any abnormality.

○ = No problem and good.

Δ = Some defects are recognized.

(B) Glossiness Measured by the 75 ° specular glossiness measurement method according to JIS Z-8471 "Glossiness measurement method".

(C) Surface roughness Rmax measured by JIS B0601 "Surface roughness" (unit: μ
m) is shown.

(D) Color The color development was visually observed.

(E) Acid resistance Judged according to JIS R-4601 "Enamel product quality standard".

(F) Contamination resistance The erasability was determined by rubbing a line drawn with a black marker for a enamel white plate (whiteboard) on a dry cloth or a compress to scrape it.

◎ = It disappears with a dry cloth.

○ = If you rub it well with a dry cloth, it will disappear.

Δ: It disappears when rubbed with a compress.

× = Marks remain even if rubbed with a compress.

(G) Weather resistance 2000 using a carbon arc type weather meter tester
After irradiation for an hour, an accelerated test equivalent to about 10 years in the Tokyo area was conducted, and the enamel surface was visually observed.

As is clear from Table 2, the frit of the comparative example can form a glossy enamel layer but cannot form a matte enamel layer having a gloss of 50% or less, or the appearance, acid resistance and stain resistance are inferior. On the other hand, the frits of the examples can form glossy and matty enamel layers by adjusting the firing temperature, and the resulting enamel layers have appearance, acid resistance, stain resistance, and weather resistance. It can be seen that the sex is excellent.

(Effects of the Invention) As described above, according to the enamel frit of the present invention, by adjusting the firing temperature, it is possible to form any enamel layer of glossy or matte quality,
The resulting matty enamel layer has a uniform and good appearance with a glossiness of 50% or less, and both the glossy enamel layer and the matty enamel layer have surface smoothness, acid resistance, and
It is excellent in stain resistance and weather resistance, and does not use harmful substances such as lead and fluorine as fritted components, so that it does not require facilities for detoxification treatment and is economical.

Claims (1)

[Claims] 1. The total amount of SiO ₂ , TiO ₂ and ZrO ₂ is 40 to 65% by weight,
At least 2 kinds of Na ₂ O, K ₂ O and Li ₂ O containing at least Li ₂ O
0-25% by weight, at least BaO and Z out of ZnO, MgO, BaO, CaO
two or more containing nO 4 to 26 _{wt%, B 2 O 3, Al} 2 O 3, Sb 5~20 % by weight of one or more of which contains at least B ₂ O ₃ of ₂ O _3, P ₂
0.5 to 1 or more of O ₅ and MoO ₃ containing at least P ₂ O ₅
The content of each of the components is 18 to 42% by weight of SiO ₂ , 14 to 28% by weight of TiO ₂ , 1 to 4% by weight of ZrO ₃ , and ₂ to 2% of Li ₂ O. 6 wt%, Na ₂ O is 0 to 11 wt%, K ₂ O is 0 to 12 wt%, ZnO is 1.5 to 10 wt%, BaO 1.
5-10 wt%, MgO 0-5 wt%, CaO 0-8 wt%, B ₂ O ₃ 5-13 wt%, Al ₂ O ₃ 0-4 wt%, Sb ₂ O ₃
Is 0-3% by weight, P ₂ O ₅ is 0.5-2.5% by weight, MoO ₃ is 0-4
% By weight, and SiO ₂ / TiO ₂ values of 65 / 35-40 / 60
Enamel frit characterized by being in the range of.