DE1596938C - Process for the production of glass colored with cobalt oxide in a relatively large melting facility in continuous operation - Google Patents

Description

13. The method according to claim 1, characterized in that the base glass, which the cobalt oxide is added, a glass with the following composition is used:

oxide Weight percent SiO, 60 to 78
1 to 18
7 to 18
0 to 9
7th to 16th
0 to 5 ΑΙ, Ο, ... 0 to 3 CaO 7 to 24
0 to 2
0.04 to 0.5
0.004 to 0.050
0.005 to 0.25 MgO Na ₂ O K ₂ O Li ₂ O R, 0 BaO Fe, O, Sulfide..... CoO

30th

35

40

14. The method according to claim 1, characterized in that the base glass, which the cobalt oxide is added, an amber-colored glass with the following composition is used:

Components

SiO,

Al ₂ O ₃

CaO

MgO

Na ₂ O

K ₂ O

Li ₂ O

R ₂ O (Na ₂ O + K ₂ O + Li ₂ O)

BaO

Fe ₂ O ₃

sulfide

Weight percent

60 to 78
1 to 18
7 to 18
0 to 9
7 to 16
0 to 5
0 to 3
7 to 24
0 to 3
0.04 to 0.5
0.004 to 0.050

• and the 'homogenized glass drained from the antechamber is deformed into an object will.

15. The method according to claim 1, characterized in that that the base glass is a standard amber glass containing iron and sulfur, The zinc oxide in the antechamber is used to reduce the intense amber color and cobalt oxide are mixed in to form a green-colored glass, and the one blown out of the antechamber is homogenized Glass is deformed into an object.

16. The method according to claim 15, characterized in that the zinc oxide in such. Amount is added that part of the iron sulfide into colorless zinc sulfide and colorless iron oxide is converted and the iron sulfide content of 0.033 to 0.130 percent by weight sulfide-bound iron and 0.012 to 0.020 percent by weight iron-bound sulfide is reduced and that cobalt oxide is admixed in an amount of 0.001 to 0.08 percent by weight.

The invention relates to a method of manufacture of cobalt oxide colored glass in a relatively large melting facility in continuous Operation.

The transition is in the manufacture of colored glass from glass of one color to glass of another color is problematic. So far it was customary to use the coloring Add material to the glass in the furnace with other glassware. The modern glass melting facilities but are very large, they can hold 100 tons and more of molten glass. Only with such amounts can it be economical work. However, if from a colored to a colorless glass or a glass of a different color is skipped, this naturally brings with it considerable difficulties. During the transition from one color to another the glass coming out of the melting device does not correspond either the original still the new color. This process is therefore extremely uneconomical.

In more recent times the so-called "frit technique" has been developed, in which a colorful Frit is added in the antechamber. In this way it is possible that the main glass melting device contains a colorless glass and the different colors are added in the antechambers be able. This makes production more economical. The transition from one color to another can be done in a few hours while using the method described above Days. In addition, so many different colored glasses can be used at the same time with the frit technique can be produced with a melting device in the same way as pre-chambers are connected to it. The frit technology is therefore associated with time savings and with a considerable reduction in glass losses

596 938

the. Smaller amounts of dye are required than when dyeing in the melting device, and the Dye is not exposed to such high temperatures in the antechamber, so that losses through volatilization be avoided. Finally, when working according to the frit technique, the melting device be operated continuously by charging and discharging, temperature control and the like. need not be changed.

But this antechamber technique requires highly concentrated frits. These must be produced in a separate operation, then carefully dimensioned and added to the antechamber. So is z. As a colorant that is added to the molten base glass in the forehearth is known, which is a glass having a viscosity below 400 poises at 1100 ⁰ C and is ground to the desired particle size. This coloring agent is therefore a glass frit, a finely ground glass containing a high percentage of coloring material. Another known material used as a coloring agent contains a large amount of boron oxide which is a glass-forming material, 10 to 30% dye, and also various other metal oxides or metal compounds commonly used in glass manufacture and refining agents. The color mixture is added either in a molten state or as a powder. In the latter case, the composition must first be fused into a glass and then pulverized.

In fact, the manufacture of colored glass in large quantities involves adding dye in the form of an unprocessed powdery oxide without first being worked into a frit, so far not been possible. So is z. B. U.S. Patent 2,916,387 that the Direct addition of a coloring metal oxide to the molten glass when coloring large quantities of glass is not possible because the oxide does not liquefy or dissolve sufficiently that in the available A uniformly colored mixture could be formed in space and time. But just at relatively large amounts of glass would require the addition of coloring oxide to the melt in the antechamber make the production of the colored glass much easier and more economical.

The invention is based on the object of a method for coloring relatively large amounts of glass to create in which all the advantages of dyeing in the antechamber are retained, but the production a colored frit is not required.

The object is achieved by a method for producing glass colored with cobalt oxide in a relatively large melting facility in continuous operation, which is characterized by the following process steps:

that a base glass melted under oxidizing conditions in the melting device and then is purified,

that the purified. Molten glass flows out of the melting device into an antechamber at a temperature below the refining temperature,
that powdery cobalt oxide (no colored frit) is added to the glass melt in the antechamber,

that this cobalt oxide and the glass melt are mixed until a uniform color

and that the colored glass thus produced is finally drained from the antechamber. After a preferred embodiment of the method according to the invention is the powdery cobalt oxide a wetting agent and / or zinc oxide which reacts to high temperatures before adding to the glass melt mixed in.

The invention and preferred embodiments are explained in more detail below.

ίο An oxide has been found that is unexpected Can be mixed well into molten glass in the antechamber and uniformly colored glass generated. This oxide, cobalt oxide, gives unexpectedly good color with high hiding power. It is further it has been found that highly temperature-sensitive wetting agents are added to the cobalt oxide as solubilizers can be. The function of these solubilizers is the wetting and the degree to increase the solution of cobalt oxide in the molten glass, causing the addition of large amounts Cobalt oxide makes possible in the antechamber.

Before discussing the practice of the invention in more detail, a description of the appropriate ones will be given Basic glasses brought.

Colorless flint glasses

Colorless flint glasses can serve as base glasses for carrying out the method according to the invention, if they have a composition falling within the limits given below. These glasses are sodium calcium oxide flint glasses. which are generally used to manufacture containers such as Milk bottles and the like can be used.

Components Weight percent SiO, 60 to 75
0.3 to 14
6 to 15
7 to 18
0 to 5 40 Al ₂ O, 0 to 5
0.00025 to 0Ό0035 CaO and MgO
Well, 0 K ₂ O 45 BaO Se

The following special soda-calcium oxide flint glasses are examples of colorless base glasses, in which the light-colored cobalt oxide according to the invention can be incorporated to make glasses blue color to come.

Base glass No. I

Components Weight percent SiO, 72.01
1.74 Al ₂ O ₃ 0.039
0.029
11.38
1.15
13.65
0.00025 to 0.00030 Fe ₂ O ₃ TiO, CaO MgO R ₂ O (Na ₂ O + K ₂ O)
Selenium ..: .....

Base glass No. II

Components

SiO ₂

Al ₂ O ₃

Fe ₂ O ₃

TiO ₂

CaO

MgO

R ₂ O (Na ₂ O
Selenium ......

K ₂ O)

'Weight percent

71.45

1.32

0.037

0.013

8.32

5.58

13.28

0.00025 to 0.00035

The conditions and procedures for making the base glasses listed above are shown in the table IX B-Il, p. 245 of the Handbook of Glass Manufacture, Tooley, Ogden Publishing Company, NY, NY, 1953.

In accordance with the broad principles of the invention, cobalt oxide can oxidize essentially any one Glass can be added. Accordingly, the invention is not limited to the examples given above Flint glasses are limited to look at. These are recommended as being suitable for the production of containers.

Flint glass based amber glasses can also be used in the practice of the invention will. These can have the oxides listed below within the specified ranges. The glasses are amber, as are commonly used in the manufacture of beer bottles and food containers be used. The glasses have a high absorption capacity for UV rays, that is light on the order of 500 nm or less, and thereby protect that in the containers food or beer in the area from the destructive effects of light.

Amber colored base glasses

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Components SiO ₂ Weight percent Al, O, 60 to 78
1 to 18 CaO 7 to 18 M «O 0 to 9
7 to 16 Na ₂ O. ... 0 to 5 K ₂ O O to 3 Li ₂ O ... 7 to 24
O to 3 R ₂ O (Na ₂ OK ₂ O-Li ₂ O) ...
BaO. 0.04 to 0.5
0.004 to 0.050 Fe ^ O ₁ Sulphides

55

60

In the manufacture of glass containers, a base glass is made of several in a melting device 100 t capacity produced. The glassware components are added to one end of the melting zone and flow into the refining zone after melting. The glass flows out of the refining zone into one or a plurality of antechambers. A device for forming a container is charged from each antechamber.

In the antechamber dyeing process, a Fri'.te in a measured amount - into the glass melt at the "point where the glass comes from the purification zone flows into the antechamber. This is done using a suitable vibratory feeder or funnel, as they are known from the relevant art, made.

Refractory stirrers are also used to mix the dye into the glass to distribute the color evenly through the whole amount of glass, so that one is the same throughout colored goods are produced.

All of these techniques are known and in the U.S. Patent 3,024,121.

In general, the melting and refining zones of the glass melting furnace are set at a higher level Maintained temperature than the antechambers. The melting and refining temperatures are usually in the range between 1560 and 1650 ° C, whereby trapped items are expelled from the melt and the occurrence is prevented from blisters in the finished product.

The temperatures in the antechamber, on the other hand, have to be largely reduced to the forming temperature of the glass so that the glass is sufficiently viscous and can be formed in the container blow molding machine. Therefore, the Vorkammertemperaturen are between about 1290 ^c C and 1040 to 1095 ° C molding temperature of the glass.

At these low temperatures or at this point occur in the known pre-chamber addition process often considerable difficulties because the glass frits mostly high softening and Liquidus temperatures that they do not melt quickly enough and have mixing of the base glass and frit is not possible at the antechamber temperatures. This is the case with those colored with chrome glass frits Glasses of chrome crystals in the finished product as a result of insufficient mixing and melting the high-chromium frit with the base glass has been determined.

It has been found, however, that cobalt oxide is easy to mix and match at antechamber temperatures melts quickly. Agitators and baffles of a known type can be used in order to mix the cobalt oxide powder homogeneously into the base glass and give it a uniform color Glass was available.

A specific particle size of the cobalt oxide is not required in the method according to the invention. As stated above, unprocessed cobalt oxide can be used. According to the invention can however, particles ranging in size from 2.360 to 0.037 mm, preferably about 0.295 up to 0.074 mm.

The only limitation for cobalt oxide is obvious that it must be free of high-melting refractory impurities.

According to the invention, cobalt oxide can be used within the wide range of 0.001 to 0.25 percent by weight, preferably from 0.01 to 0.25. Weight percent, based on the glass composition. Get strong with the preferred amounts got green glasses.

The following examples illustrate the various process steps of the process according to the Invention. . ■.

209 515/191

Example I. (Colorless flint glass base glass plus cobalt oxide)

In this and the following example, commercial cobalt oxide became colorless flint glass given within the wide range given above, so that a glass composition with about 0.2 weight percent cobalt oxide was obtained. The addition was carried out at antechamber temperatures. The color obtained was dark blue.

The glass had the following theoretical composition, based on the glass set.

Components Weight percent SiO ₇ 72.01
1.74
0.039
0.029
11.38 Al, O,. . 1.15
13.65
0.00025 to 0.00030
0.2 Fe, O, TiO, CaO MgO ... R ₂ O (Na ₂ O + k ₂ O) ....
selenium CoO '

In the composition listed above, iron was present as an impurity in the sand and TiO ₂ as an impurity in the Al ₂ O ₃ .

Example II

The glass had the following theoretical composition, related to the glass set:

Components

SiO ₂ .
Al ₂ O ₃
Fe ₂ O ₃
TiO ₂ .
CaO.
MgO.
R ₂ O ..
Selenium.
CoO.

Weight percent

71.45 1.32 0.037 0.013 8.32 5.58

'13.28

0.00025 to 0.00035 0.2

45

Components

SiO ₂

Al ₂ O ₃ ......

CaO + MgO

Na ₂ O

K ₂ O

BaO

selenium

CoO

Weight percent

60 to 75

0.3 to 10

6 to 15

12 to 18

0 to 5

0 to 5

0.00025 to 0.00035 0.005 to 0.25

6o

Example III

(Amber colored flint glass plus cobalt oxide)

In this example, commercial cobalt oxide turned into amber glass at antechamber temperatures given in such amounts that 0.1 weight percent cobalt in the glass composition oxide templates. The color obtained was Scottish green. This is an unexpected color change and apparently caused by the blending of the blue of the cobalt oxide with the amber color produced by the Iron sulfide is caused.

The glass had the following theoretical composition:

15 components

SiO ₂

Al ₂ O ₃

Fe ₂ O ₃

CaO

MgO

Na ₂ O

K ₂ O

Lithium oxide

Sulphides

CoO

Weight percent

71.97

1.884 0.042

11.47 0.11

14.08 0.381 0.001 0.014 0.1

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40 Example III shows a single-colored glass produced from an amber-colored flint glass as the base glass and cobalt oxide. Glasses according to the invention, with an amber-colored base glass, are encompassed by the following formulation range:

Components

Examples I and II represent colored glasses made from colorless flint glass as the base glass and cobalt oxide can be produced. All based on flint glass fall within the scope of the invention Glass compositions that fall into the following formulation range:.

SiO ₂ Al ₂ O ₃ CaO 'MgO Na ₂ OK ₂ O Li ₂ O., R ₂ O .. BaO Fe ₂ O ₃ sulfides. CoO weight percent

60 to 78 1 to 18 7 to 18 0 to 9 7 to 16 0 to 5 0 to 3 7 to 24 0 to 2 0.04 to 0.5 0.004 to 0.05 0.005 to 0.25

The preceding examples demonstrate the feasibility of the invention and at least part of the Color range that is possible through them.

As already stated above, the invention also includes the addition of a powdery solubilizing agent Wetting agent in connection with the powdery cobalt oxide, resulting in an unexpectedly fast Dye addition is made possible. This increases the rate of cobalt oxide uptake to a surprising extent through the base glass and reduces atomization.

Thus, according to the invention, compounds from the group of alkali and earth metals can be used as solubilizers

alkali borates, alkali and alkaline earth silicates and alkali and alkaline earth phosphates are used.

Such compounds are e.g. B. sodium silicate, sodium borate and sodium phosphate, in powder form Used.'If a mixture of powdery cobalt oxide and wetting agent is in the antechamber of the If the glass melting device is added, the wetting agent is immediately put in by the heat of the antechamber passes the molten state, it immediately wets the cobalt oxide, and starts instantly the fusing and mixing of the cobalt oxide with the molten base glass. By using Using a suitable stirring device, the color becomes homogeneous in the molten base glass mass distributed, and a uniformly colored mass is quickly formed.

In continuation of this aspect of the invention For example, an alkali metal oxide can be added in small amounts to aid in wetting the cobalt oxide facilitate.

It has been found that an amount of solubilizing wetting agent, based on the amount of Cobalt oxide, in the range of 0.2 to 10 percent by weight, a very suitable additive composition represents.

Evaporation losses are very low when working according to this embodiment of the invention; therefore, the wetting agent has little, if any, effect on the final product and its properties.

Due to the fact that cobalt oxide is not a reducing agent, the degassing is low compared to the known technique. If a reducing agent was previously added in the antechamber, CO ₂ and other released gases remained in the glass as small bubbles (gispen or foam) because the antechamber temperatures were not high enough to purify the glass. It has now been found that physically entrapped gases in the powdered additives are driven off at temperatures such as prevail in the antechamber when the wetting agent is placed on the surface of the molten glass. This brings another unexpected benefit in connection with the present invention.

Dark, even very dark green tones can be achieved by introducing cobalt oxide into an amber-colored one Base glass can be obtained quickly according to the invention.

This is particularly advantageous since cobalt oxide is a normal blue producing oxide.

According to the invention, zinc oxide and frits containing zinc oxide can also be mixed with the cobalt oxide in various ways Concentrations can be combined to produce wide color ranges from greenish yellows to yellow-green- ' tones, greens and blues.

When cobalt oxide is used alone in an amber base glass, the amber color is retained and the color change occurs by mixing the amber color with the blue created by the cobalt oxide. However, the addition of zinc oxide also changes the basic amber color. This is due to the fact that some iron sulfide, which creates the amber color, reacts with the zinc oxide to form zinc sulfide, which is colorless. This reduces the intensity of the yellow tone. Then the blue of the cobalt oxide provides a variety of possible shades of green.
So z. B. Champagne green can be made from a normal amber base glass by adding zinc oxide along with the cobalt oxide. The zinc oxide takes away some of the amber color, and the cobalt oxide blue, mixed with the resulting, less intense amber color, gives champagne green.

The above principles are essentially the results of several test series, which are summarized in the tables below.

Experimental Weight percent Fe ₂ O ₃ S. CoO Dominie
rende purity Luminosity comment number 0.182 0.028 0 wavelength 0.182 0.028 0.10 nm % % Standard amber colors 513 0.182 0.028 0.12 579.8 86.6 36.1 very dark green 514 566.2 49.3 5.5 very dark green 515 570.3 61.7 8.2

(The experiments listed above show the colors that can be produced according to the present invention by adding varying amounts of cobalt oxide to standard amber colors can be obtained. Green tones are produced.)

Experimental Weight percent % % % Dominie
rende purity Luminosity comment number Fe ₂ O ₃ S. CoO wavelength 0.033 0.012 0 0.033 0.012 0.02 nm % % Light amber 500 0.033 0.012 0.04 576.0 46.6 68.9 Greenish yellow 501 0.033 0.012 0.06 572.6 32.1 50.1 green 502 0.033 0.012 0.08 565.2 16.1 36.6 blue 503 514.4 3.6 27.9 blue 504 486.3 15.1 21.1

(The above experiments demonstrate the unexpected effects obtained by first one Standard amber modified by decreasing the amount of iron sulfide paint and then cobalt oxide admits. The colors vary from greenish yellow to blue with increasing cobalt oxide content.)

13th % ■ %% CoO 1 596 938 Luminosity U comment Weight percent Fc ₂ O ₃ S. 0 Experimental 0.130 0.020 0.02 Dominv
rendc purity % Light amber ~ w & OU Viii /
number 0.130 0.020 0.04 wavelength 50.2 Greenish yellow 0.130 0.020 0.06 nm % 36.9 Yellow-green 525 0.130 0.020 0.08 578.1 75.8 27.3 green 526 0.130 0.020 575.8 67.6 19.5 almost champagne 527 573.4 58.6 15.3 green 528 570.3 47.5 529 566.5 35.6

(The experiments cited above show further embodiments of the invention. The light amber color gives lighter yellow and green tones with cobalt oxide.)

Claims (12)

Patent claims: 1. Process for the production of cobalt oxide colored glass in a relatively large scale Melting device in continuous operation, characterized by the following process steps: that a base glass is melted under oxidizing conditions in the melting device and then refined,
that the refined glass melt flows out of the melting device into an antechamber at a temperature below the refining temperature, that powdered cobalt oxide (no colored frit) is mixed with the glass melt in the antechamber, that this cobalt oxide and the glass melt are mixed until a uniform color and that the colored glass thus produced is finally drained from the antechamber. 2. The method according to claim 1, characterized in that the powdery cobalt oxide before Addition of a wetting agent and / or zinc oxide that is sensitive to high temperatures to the glass melt are mixed in. 3. The method according to claim 2, characterized in that the wetting agent is an alkali or alkaline earth silicate, Borate or phosphate is used. ' 4. The method according to claim 1, characterized in that that the glass is melted and refined under oxidizing conditions at temperatures between 1425 and 1650 ° C, at a Temperature between 1315 and 1040 ° C flows out into the antechamber and 0.001 to 0.25% powder Cobalt oxide, based on the weight of the glass, are added. 5. The method according to claim 4, characterized in that the cobalt oxide powder is a small Amount of wetting agent according to claim 3 is admixed. 6. The method according to claim 1, characterized in that a glass of the following composition is melted: · Components SiO ₂ Al ₂ O ₃ CaO + MgO Na ₂ O K ₂ O BaO Se Weight percent 60 to 75
0.3 to 14 6 to 15 7 to 18 . O. to 5. O to 5
0.00025 to 0.00035 55 and this melt in the antechamber 0.001 to 0.2% cobalt oxide, based on the weight of the glass, preferably mixed with a wetting agent that is sensitive to high temperatures will. 7. The method according to any one of claims 1 to 3, 5 and 6, characterized in that the melting of the glass, the refining, the outflow into the antechamber and the admixing of the cobalt oxide powder is carried out under reducing conditions. _; ;, 8. The method according to any one of claims 1 to 6, characterized in that the melting of the Glass, the refining, the flowing out into the antechamber and the mixing in of the cobalt oxide powder is carried out under oxidizing conditions. 9. The method according to claim 1, characterized in that the base glass, which the cobalt oxide is added, a glass with the following composition is used: oxide SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ TiO ₂ CaO MgO R ₂ O (Na ₂ O + K ₂ O) selenium CoO. ' Weight percent 72.01 1.74 0.039 0.029 11.38 1.15 13.65 0.00025 to 0.00030 0.2 10. The method according to claim 1, characterized in that as the base glass, which the cobalt oxide is added, a glass with the following composition is used: oxide Weight percent SiO ₂ 71.45
1.32
0.037
0.013
8.32
5.58
13.28
0.00025 to 0.00035
0.2 Al ₇ O, Fe ₇ O, TiO, CaO MgO R ₇ O selenium CoO 11. The method according to claim 1, characterized in that that as the base glass to which the cobalt oxide is mixed, a glass below Composition is used: oxide Weight percent SiO, 60 to 75 ΑΙ, Ο, ... 0.3 to 10
6 to 15
12 to 18 CaO + MgO
Na ₂ O 0 to 5 K ₂ O 0 to 5
0.00025 to 0.00035
0.005 to 0.25 BaO selenium CoO 12. The method according to claim 1, characterized in that the base glass, which the cobalt oxide is added, a glass with the following composition is used: oxide Weight percent ■ SiO ,, 7197 Al, O, 1,884
0.042
11.47
0.11 Fe ₂ O ₃ 14.08
0.381
0 001 CaO 0.014
0.1 MgO Na ₂ O. K, 0 lithium sulfide CoO IO 20th