JP2006089375A - Method for producing white frit and glass article having white stripe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow the coefficient of thermal expansion of a white frit to substantially coincide with that of base glass; and to allow the generation of residual stress to hardly occur in the interface between the white stripe part and the base glass. <P>SOLUTION: The coefficient of thermal expansion of the while frit can be allowed to almost completely coincide with that of the base glass by producing two kinds of white frits comprising a white frit having a larger coefficient of thermal expansion and a white frit having a smaller coefficient of thermal expansion than that of the base glass and mixing the two kinds of white frits so that the coefficient of thermal expansion of the mixed white frit coincides with that of the base glass and the mixed white frit is incorporated into the base glass. As a result, the generation of residual stress hardly occurs in the interface between the white stripe part and the base glass. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing white colored glass products.

  The most common glass product manufacturing method will be described with reference to FIG. The glass melted in the melting furnace 1 is formed on the gob 11 through the forehouse 2, the spout 3, and the orifice 4. The gob 11 is supplied to the glass product molding machine 9 by the delivery 8 and molded as a glass product. The forehearth 2 has a cooling section 2a and an equalizing section 2b, and the glass is cooled or heated while passing through these sections and adjusted to a predetermined temperature. The spout 3 is a portion for storing and keeping the glass necessary for making the gob 11, and a tube 6 for adjusting the amount of the glass is provided at the center. Inside the tube is a clay plunger 7 that moves up and down. When the clay plunger 7 is lowered, the glass is pushed out from the orifice 4 below the spout 3 and cut by the shear 5 to become a gob 11. The gob 11 is supplied to the glass product molding machine 9 by the delivery 8 and molded as a glass product.

  When manufacturing a glass product with color stripes, as indicated by an arrow A, a colorant (color frit) is usually mixed into the base glass in the foreground 2 to form a gob with color stripes. When this gob with color streak is molded with a molding machine, a glass product with color streak is produced. The stirrer 10 stirs the base glass and the molten color frit in which the color frit is melted. When this is operated, the base glass is uniformly colored to become colored glass. When manufacturing glass products with color streaks, the stirrer 10 is stopped, so that the molten color frit and the base glass are not completely mixed, but become the color streak glass and reach the spout and orifice, and gob with color streaks. Is formed. When this gob with color streak is molded with a molding machine, it becomes a glass product with color streak. Further, as indicated by the arrow B, when a coloring material is mixed in the vicinity of the spout 3 or in the spout 3, a clearer color streak can be formed. Furthermore, as shown by the arrow C, it is possible to mix a coloring material inside the tube 6, and not only this can form a clearer color streak, but also the color streak inside the gob as shown in FIG. Can be formed. When a glass product is molded with this gob, color streaks enter the thickness of the glass product.

  There are various compositions of white frit for coloring glass white, but it is very difficult to produce glass products with white streaks using these conventional white frit, and the color streaks are thin. There are problems that it is stable, has poor solubility, has a narrow working temperature range, and has a high rate of defective products due to cracking at the interface between the color streak and the base glass due to a small impact or temperature change.

As the opacifier used for the white frit, As ₂ O ₃ , TiO ₂ and F ₂ are used. White muscle containing glass product using the white frit containing F ₂ as opacifier, a white color muscle thin unstable, it is impossible to obtain a desired thickness of the color streaks. The white streaked glass product using a white frit containing As ₂ O ₃ or TiO ₂ as an opacifier has a relatively thick white color streak and a stable thickness, but the coefficient of thermal expansion of the white frit Unlike soda lime glass, which is a base glass, cracks are likely to occur at the interface between the color streak portion and the base glass. In addition, the white frit using As ₂ O ₃ has a drawback that it is easily discolored, and a discoloration problem occurs depending on the frame. This is because a large amount of PbO is blended in the white frit to insolubilize As ₂ O ₃ and increase the milkiness. Furthermore, As ₂ O ₃ is highly toxic, the working environment in which it is used has a safety problem. Further, in the case of a white frit using TiO ₂ , the glass softening point is as high as about 650 ° C., so that the solubility is poor and the working temperature range is narrow.

  Since white glass is a glass containing fine crystals, the thermal expansion coefficient differs between the crystalline part and the amorphous part. Even if the thermal expansion coefficients of the base glass and white frit match in the normal thermal expansion coefficient measurement, if the product is actually manufactured as white streaked glass, strong stress remains at the interface between the color streaks and the base glass, causing damage. Cheap. Accordingly, it is extremely difficult to reduce the residual stress at the interface by actually combining the thermal expansion coefficients of the base glass and the white frit.

  The present invention has been made to solve the above-described problems. The white frit has substantially the same thermal expansion coefficient as that of the base glass, and hardly generates residual stress at the interface between the color streak portion and the base glass. The present invention provides a method for manufacturing a lined glass product.

[Configuration 1]
The present invention includes a step of producing two types of white frit, a white frit having a smaller thermal expansion coefficient than that of the base glass and a large white frit, and mixing the two types of white frit to match the thermal expansion coefficient of the base glass. And a step of mixing the mixed white frit into the base glass.

  White glass (frit) is difficult to match the coefficient of thermal expansion completely with that of the base glass, but two types of white frit, a white frit having a smaller coefficient of thermal expansion than that of the base glass and a large white frit, are manufactured in advance. By mixing these two types of white frit so as to match the coefficient of thermal expansion of the base glass, the coefficient of thermal expansion can be made to match the base glass almost completely. For example, when the thermal expansion coefficient of the base glass is 87 × 10 −7 power / ° C. (hereinafter, the value of the thermal expansion coefficient is expressed by omitting [× 10 −7 power / ° C.]). The white frit having a small thermal frit can be about 80 to 85, and the white frit having a large thermal expansion can be about 89 to 91. The ratio of mixing two types of white frit can be easily determined by making a prototype and checking it. Further, even if the thermal expansion coefficient of the base glass slightly changes during the manufacturing process, it can be easily dealt with by appropriately correcting the mixing ratio of the white frit.

[Configuration 2]
Further, the present invention is the manufacturing method according to Configuration 1, wherein the two types of white frit are both in percentage by weight, wherein F ₂ is 2% or more and 8% or less, PbO is more than 10% and less than 25%, SiO ₂ Over 50% and under 65%, B ₂ O ₃ over 1% and under 10%, Na ₂ O over 5% and under 15%, and Ca0 over 2% and under 8% It is a manufacturing method of the glass product with white stripes characterized.

F ₂ is an opacifier that produces fine crystals of CaF ₂ and NaF in the glass to make the glass milky white. If it is less than 2%, the milky white color becomes thin, and if it exceeds 8%, there is not much change in the coloring effect, which is useless. The working environment by using F ₂ as an opacifier and safer, it is possible to increase the working temperature range. By adding an appropriate amount of PbO, the specific gravity of the frit can be increased, and the color streak can be made thick and stable. If PbO is 10% or less, the color streaks are thin and unstable, and if it is 25% or more, discoloration is likely.

  A thick and stable color streak can be realized by making the specific gravity of the white frit 0.1 or more larger than the specific gravity of the base glass. When the specific gravity of the white frit is small, the melted frit floats on the base glass 12, sinks due to the descending force of the clay plunger, and reaches the orifice. However, since the specific gravity is small, it is difficult to descend in the base glass due to buoyancy, so that the color streaks are inevitably thin or a distorted pattern. When the specific gravity of the white frit is large, the melted frit sinks smoothly by the descending force of the clay plunger, reaches the orifice, and a stable thick color streak is formed. FIG. 1 shows a state where a supply frit 13 pre-melted with a white frit of the present invention is continuously charged into a base glass 12 in a tube 6 and mixed therein. The supply frit 13 having a heavier specific gravity than the base glass 12 enters the base glass 12 without staying on the surface of the base glass, and sinks smoothly due to the descending force of the clay plunger 7, and a stable thick white streak gob 11 is formed. It is formed. White stripes are formed inside the gob 11, and when a glass product is molded with the gob, a glass product with white stripes in which white color stripes are included in the thickness of the glass product is formed. The supply frit can be mixed without pre-melting, and the mixing place is not limited to the inside of the tube.

White frit, in weight percent, may be SiO ₂ is less than 65% exceed _50%, B 2 _{O 3} is less than 10% exceed 1%, Na ₂ O is less than 15% than 5%. By setting each of the above components within this range, the coefficient of thermal expansion of the frit can be made substantially equal to that of soda lime glass which is a base glass, and the working temperature range can be sufficiently widened. If SiO ₂ is 50% or less, the coefficient of thermal expansion becomes too large, and if it is 65% or more, the softening point is increased and the working temperature range is narrowed. If B ₂ O ₃ is 1% or less, the coefficient of thermal expansion becomes too large, the frit solubility is poor and the working temperature range is narrowed, and if it is 10% or more, the coefficient of thermal expansion becomes too small. If Na ₂ O is made 5% or less, the coefficient of thermal expansion becomes too small, and the softening point rises to narrow the working temperature range.

  The manufacturing method of the white streaked glass product of the present invention can match the thermal expansion coefficient almost completely to the base glass, further reduce the residual stress at the interface between the color streak portion and the base glass, and crack the product. Can be prevented. Further, even if the thermal expansion coefficient of the base glass slightly changes during the manufacturing process, it can be easily dealt with by appropriately correcting the mixing ratio of the white frit.

Further, as a white frit in terms of weight percentage, F ₂ is 2% or more and 8% or less, PbO is more than 10% and less than 25%, SiO ₂ is more than 50% and less than 65%, and B ₂ O ₃ is more than 1% and 10%. %, Na ₂ O exceeding 5% and less than 15%, and Ca0 exceeding 2% and including less than 8%,
The white streaks can be provided thick and stably, the solubility can be improved and the working temperature range can be widened, and the thermal expansion coefficient can be made almost equal to that of soda-lime glass which is a base glass. Therefore, it is possible to easily produce a glass product having a stable white streak having a desired thickness, to reduce the residual stress at the interface between the color streak portion and the base glass, and to prevent the product from cracking.

(1) _{F 2} 5% by weight percentage, PbO is 20%, SiO ₂ is _55.0%, B 2 _{O 3} is 1.5%, Na ₂ O is 10%, Ca0 is 3%, _Al 2 O White frit ₃ with 5% and As ₂ O ₃ 0.5%, and (2) 5% by weight F ₂ 5%, PbO 20%, SiO ₂ 56.5%, B ₂ O ₃ 1 A white frit of 0.5%, Na ₂ O 8.5%, Ca 0 3%, Al ₂ O ₃ 5% and As ₂ O ₃ 0.5% was made. The white frit (1) has a thermal expansion coefficient of 90.7, a specific gravity of 2.82 and a softening point of 541 ° C., and the white frit of (2) has a thermal expansion coefficient of 84.47, a specific gravity of 2.81 and a softening point. It has the characteristic of 550 degreeC. The two types of white frit were mixed at a ratio of 1: 1. The mixed white frit was melted at 1300 ° C. and 1% was added to the base glass as white streaks. The composition of the base glass is as follows: SiO ₂ 73%, Al ₂ O ₃ 2.1%, Na ₂ O 13.7%, Ca 0 11%, thermal expansion coefficient 86.9, specific gravity 2.49. It has a characteristic of a softening point of 732 ° C. The outflow of white streaks was stable, and a clear milky white colored glass product was obtained. In addition, almost no residual stress was observed at the interface between the color streak and the base glass.

It is sectional explanatory drawing of the spout part which shows the use condition of the white frit of this invention. It is explanatory drawing of the manufacturing method of glass products containing a color stripe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Fore hearth 3 Spout 4 Orifice 5 Shear 6 Tube 7 Clay plunger 8 Delivery 9 Molding machine 10 Stirrer 11 Gob 12 Base glass 13 Supply frit

Claims (2)

  Producing two types of white frit, a white frit having a smaller coefficient of thermal expansion than the base glass and a large white frit, and mixing the two types of white frit to match the coefficient of thermal expansion of the base glass; And a step of mixing the mixed white frit into the base glass. 2. The manufacturing method according to claim 1, wherein each of the two types of white frit has a weight percentage of F ₂ of 2% to 8%, PbO of more than 10% and less than 25%, and SiO _{2 of} more than 50%. White streak characterized by containing less than 65%, B ₂ O ₃ exceeding 1% and less than 10%, Na ₂ O exceeding 5% and less than 15%, and Ca0 exceeding 2% and less than 8%. Manufacturing method for glass products.

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