DE1909187C - Process for the production of opal glass objects - Google Patents

Description

C'weight percent CaO
de ¹ ',! chtspro / ente N! z ()

j 4 to i.5

'~. Method / to create I! \ On opal glass objects • according to one of the claims only compositions S to II. Characterized in that a (.ilas ^ etieiiskind formed from a glass of the specified composition and in the course 'Jes (• οΓπηοΓϊ.ιΐΐίι ; -; is opalescent.

P '. Method according to claim 17, characterized in that almost complete opalescence / by cooling the objects to a temperature corresponding to a viscosity around K) ⁷ - "" poise is brought about.

Temperature is called viscosity
10-poi:, e

Melting temperature

Viscosity at the melting temperature OK ^! - poise

Thermal expansion coefficient 45 · IO '! C.

((ι to 300 C]

'J. Method according to claim 1. that a glass is used which has the following Components contains:

The hearing relates

10. The method according to claim '). characterized in that a glass is used in which the Bedmir.'nii

fulfilled is ·.

1 1. The method rsaj ^ one of claims s to 10, characterized in that an iikts is used in which di. Alkaiioids consist of Na ₂ O.

12. \ experienced rvc'r. one of claims 3 to 1 1. characterized in that the heat treatment urn nii · the one for tensioning is kiimbinated.

13. Proceedings against a ucr A'i-priiciie! 2 or 12. thereby üe '-. Ennzeichiie :. d.iK at the yt ';ir; ncbchiiiivi!: i! i2 Fcinpcrjiuren / w ι -, hen 5 ^ 5 and t ^<: ' C for '5 minutes ;: ^! v · "^; SM: '■ ·, jnge- ♦;:" dl.

^! i. \ 'learn from Λη ^ ρτ; .Ii 1 3.dad ^! ..r ^ h jekenn- 1 ■ chi'el.dafn'e'npcratiirci! /·.-. : -c hi: - ¹ O! 1 ■ .nd S: 50 C »:: iir -.! Hi 30 M: r:; aj! I hi ^. · ■ \
the.

1'·:;; per.ttiiri.11

. e: 'f it.re

'. ■■ <, - "fs

A'i ·· '

L; i ..rue ¹ -, t: ldt who - ..!; 12. -.!.:. Ii: r -. 'H ge: h; u .:' the iteration from ic to usable for it

Giäser.

ί-.s are opal glasses of various kinds began. at the '! will make special opalescent coatings'. like 1'tane and tin compounds. Fluoride. Sulfates. Chlorides, phosphates and various other salts used, of these 1 have luoride opal glasses many times over Application for Belei'chmngs -.wecke found there be; them another area of palcszenz (Cirad's Opacity) can be adjusted.

HersteüuiiL! of opal glasses mn special op. illuminating means hriniri at the Gkisfabnkatioii special L'm-.tän-de nil himself. The most common opals-zieruniisniitici. , especially Hu. ^ir i (.le. have a highly corrosive effect on the linings of glass melting furnaces, so that the furnace must be overhauled at relatively short intervals. s of the furnace premature or Au preferred .- melt the Opaleszierung can occur nittel 'rnd this can / drove the Opalcszierungsmiuels at the bottom of the melting furnace n accumulations, so a IA υ corrosion there .vird considerably increased. the resulting l The uniformity of the distribution of the opalescent agent leads to correspondingly uneven results, and in general the uniform channeling of the opalescent agent in itself regrets difficulties, so that a uniform product can easily be obtained Lm can be further disadvantage be-rcannter Opalg'äser is enteric that often the molten glass already .eibst opaleszen ¹ is. this erhöhl the Brennstoffk '^ he ,. since the low radiation from such melts reflects more and is less absorbed than from clear melts.

Ils are fer.er Op.ilglä ^. known where the

j / i inibuni; not duivi; a special Opaleszienmg ·· - Miiilek but is conditioned by I · '.glasjug. l'.m the i ntgkisung in proportion! in a reliable way. mü -.- e; i such Gkiser Zii-, aniinenset / u: i-Ueη, iiifwei-en. the man -or, -! in glass production

^r > 1 just avoid !. w <e: l mc iv.it poor processing properties '■ c-rkiitip' · mihI. Liei-pielweise are bek-mnle f) _; .i: di '! iiser of this kind by extreme SiO ^ - (CaO MgOi-verl-ahilis-e g -.- denotes. ie, they ei'ithaheii ν receive.'il!! ·> ηι! Ί [ Αιΐ! ·.: ■ _ ·! SiO, and possibly

6-, '', oci'i Ii ^ O ₁ . re ·!. '·, ii ipi comparison d; / u weniL' f-.nlalkaii: four :: i!.-.- e stall ·, -,. are glasses! linen especially start. z: ir I ;;!: 'lavi'u ·. : · --.- -ι:! ·: Ί ied <> ch considerably, cliw ienger

The field of application of opal glass is itself in the younger Zeil suirk expanded, and / was not me for lighting fixtures. Illuminated globes. Tilter, scientific / wake up and the like, but aiuh, for example in the packaging industry / for the manufacture of min containers for hair and body care products. Deodorants, Resources and the like, especially for the latter Applications, it is highly desirable, opal glass surfaces with usual high-speed / U can manufacture glass forming machines in rational mass production, whereby accordingly the The glass used should be easy to process, chemically stable, heat-resistant and non-corrosive and overall the cost of producing the opal glass objects should be as low as possible. From the For the reasons outlined above, the known opal glasses cannot meet these requirements without only imperfectly fulfill.

After the lirlindiing the given task is solved by a method for the production of opal glass objects, which is characterized in that it consists of an alkaline earth aluminum silicate glass. that the following Contains ingredients.

UcsMiullcil weight percent

SiO ₂ 55 to 76

AI ₂ O _n i, 5 to! 2

B, O _a O to 13

CaO 5 to 20

McO O to 15

Na., O 1 to <11

K ₂ C) O to 5

Li ₂ OO to <2

with the conditions

(CaO j MgO 10 to 30

(Na ₂ OIK ₂ O) Jl

Weight percent B ₂ O ₃
Weight percent Na ₂ O

(SiO ₂ i ALO,; B ₂ O _n

• CaO I MgO j- Na ₂ O)> 95

the glass objects are formed and an in-siiu phase separation is brought about by a heat treatment which makes glass objects opalescent.

According to the method according to the invention is thus a non-corrosive glass is used that does not contain any special opalescent agents and because of its is easy to process within the usual, balanced composition: the opalescence takes place through phase separation and not through glassiming. those used according to the invention On the contrary, glasses can even have a high resistance to tinted glass.

As only common components for the glass attachment that are available in large quantities and with too little carbon are required, and since the opalescent heat treatment is carried out on the finished articles can be, are both the raw material costs and the operating and manufacturing costs are low. Another benefit is dal! the degree of achieved Opalescence due to the way it is heat treated can be controlled reproducibly in wide grunts.

The η.κΐι of the present description transform

Glass usually contains six main components Meaning should be briefly discussed below.

The predominant glass-forming oxide is silicon dioxide (SiO ₂ ). whose Bedeuluni: is known for the glass.

The Cilas also contains aluminum oxide (AL <) ..). there·, two / wake up:

a) Alumina increases the resistance to glassization during the opalescent heat treatment;

b) the Opaleszierungsgeschwindigkcil can be controlled by a suitable choice of the ΑΙΛλ, sound, since the opalescence speed decreases _{with increasing Al 2 O, content.}

Both of these effects are dependent on the glass viscosity, and this is largely determined by the ALO ₁ content

The alkaline earth oxides (CaO and MgO) are common

ίο both toihanden and have the / wake, the chemical To increase the stability of the finely divided opalescent phase. These oxides also affect the glass viscosity.

Boron oxide (B ₂ O.) primarily promotes opalescence.

ie. the incidence of opalization increases with increasing B ₂ O ₁₁ gel. Sodium oxide (Na ₂ O) serves as the flow center in the usual way! and on the other hand it counteracts the tendency to opacification, so that the ratio of NaO to B ₂ O _{1 plays} an important role in determining the time and temperature of the opalcation heat treatment.

Other alkali oxides, such as potassium oxide (K ₂ O) and lithium oxide (Li ₂ O), can also be present in the amounts indicated.

The heat treatment required for the opalescence naturally depends on the special composition chosen within the above-mentioned zen. It has been shown that thermal opalescence can also be achieved with glasses according to the above-mentioned range limits Again, Na ₂ O still _{contain B 2} O ₃ , but the controllability of the opalescence process is not as good as with glasses containing these two components. Therefore, glass compositions containing both Na ₂ O and B ₂ O ₃ are preferred 1 Furthermore, lithium oxide is preferably not used, since this oxide promotes the tendency towards devitrification at elevated temperatures. Accordingly, in a further embodiment of the invention, the specified method is preferably carried out with a glass which has the following components:

Ingredient weight percent

SiO ₁ 60 to 70

AUO ₃ 4 to 8

B, 6, 1 to 9

CaO 6 to 16

MgO 4 to 12

Na ₂ O 3 to 7

with the conditions

(CaO; MgO) 14 to 21

(Na ₂ O; K ₂ O) 8

Weight percent B., O,,.

0.2 to 3
Weight percent Na ₂ O

(SiO .. j ALO,; IM)., CaO

; "MgO"; Na ₂ O "> 98

In accordance with the usual pia \ is colorizing Oxide, bei-, ρ ic N w c im- il ic (ixide son kol ·, li. Kupkr. Chrome. NkU-I and manganese, are added to opaleszeulcs'. different colors and shading to divide. I lic I; iibcii and shades In doing so, through the oxygen level, dcrSchmcl / c. the length of time uiul the temperature of the heat'.K'handluiig being controlled.

Such coloring oxides generally do not exist no more than about 2 percent by weight of the glass compound set.

In carrying out the method according to the invention, an alkaline earth aluminum silical glass is selected in all of the above-mentioned composition ranges. The small proportions of H ₂ O and Na ₂ O are advantageous in order to promote and / and control the desired phase change. It has been determined that the presence of both of these ingredients is desirable. in order to be able to control the transition from the initially transparent glass to the opal / cnl state as much as possible.

The glass with the chosen composition will melted and formed into objects by customary methods. l. Door the glass offset can be ordinary Starting materials are used, provided that that from them the desired composition can be cebüäei. The selection of Aus.eanjis materials is based essentially on economic considerations .. Fs of course. dall the melted C j ta ·· as homogeneous as possible scm should be before off The glass areas are shaped for him.

After the glass surface has been molded. it is subjected to a certain heat treatment for a period of time that is sufficient to bring about the desired phase separation.

In a further embodiment of the invention glasses are specified in which the phase separating and thus opalescent heat treatment of the type described with a conventional stress-relieving heat treatment can be combined. This is clearly advantageous in the manufacture of the opal / enler glass objects. F-in such a founding facility thermal Opalescent alkaline earth aluminum silicate glass can contain the following components:

Ingredient weight percent

SiO, 66 to 69

AI ₁ O ₃ at 6

BO ₃ <to 8

CaO - MgO 13 to 18

Na ₂ O at 5

under the condition

Weight percent CaO,
¹ by 1.4

Weight percent MgO

In embodiments of the present invention, glasses are also specified in the context of the compositions mentioned, in which the phase separation and thus the opalescence occurs under the influence of the thermal conditions that prevail during the molding process, so that the glass after the ί · "-; πηιιημ op; iles7cni is. This is clearly a very special'- ·!" Advantage because a special heat treatment can be omitted. In the case of glasses of this type, essentially complete opalescence can be obtained by cooling the objects to a temperature at which the viscosity is about | () ⁷ · ⁶⁵ Poisc. Such a ciliiuliiiigsgc according to thermally opalescent alkaline earth aluminum aluminum oxide glass can contain the following components:

component
SiO ₂ ..

weight pro / cnt 71

CaO 'MgO

IU) ₁₁

Alkali oxide c

with a ratio of 1.5

MgO

5 10 12

Other crfindimgsgcäßc glasses that are in similar Wise, during the conditions prevailing during the norming process, become opaque, are further back specified.

Unless an inventive glass composition is used is used, in the manner indicated, the heat treatment serving for opalescence can be combined with the relaxation heat treatment or even by the conditions prevailing during the Eornnorganges can be represented, according to the invention, the glass area according to the standard is a subjected to a certain heat treatment in order to achieve a certain degree of opalescence. The invention describes on the one hand a large range of possible compositions for thermally opalcs zicrbarcs Glass and, on the other hand, provides information about the designation of these compositions as that for the Opalescence required heat treatment.

The relationship between time and temperature during heat treatment depends primarily on the composition of the glass used. It will be understood that higher temperatures require a shorter period of time to produce the desired phase separation and opalescence, but that at such high temperatures the glass is more easily deformed and devitrified. For purposes of the invention, temperatures from about 600 or 65 ° to about 980 for 15 minutes to about 64 or more hours are satisfactory. In general, for economic reasons, temperatures between 650 and 850 ^: for 30 minutes to about 8 hours are preferred. In the case of combined phase separation and relaxation heat treatment, temperatures between 565 and 850 ° C. for 15 minutes to 8 hours can be used according to the invention, preferably temperatures between 760 and 815 ° C. for one hour.

When it comes to heat treatment, it is generally good that shorter ones Duration and lower temperature favor the formation of translucent glass while longer periods of time and higher temperatures favor the formation of densely opal glass.

If the heat treatment has been carried out correctly is, v. is the glass essentially in two separate, but continuous glass phases separated. (Gcwc'iriich is not a crystalline phase \ orhi.r.Jen.) on Gn; ui This phase separation makes the glass opaics / ioend.

One of these glass phases in the rich in aluminum oxide. Alkaline earth oxides. Sodium Oxide and Horox'd Ijjj, Glass phase is vechälinism ißi »..labil uni, iCLienuh 1 Acids and alcohols are fairly poor. i) ie, '. niier ■

909

Glaspliase is also rich in Nili / itinu! Io \ id ι «ml -very stable, Is is too heoh: u_hieii. '.IaIA ilas apportionment ratio the Pha-en iicui \ cihiiItiiis their corresponding correspondence Components in the original file corresponds to.

As biTcils mentioned, the higher temps require pc-ι inside a shorter /eitd.iiiei. do the desired To bring about phasinlenniing, alvr da- (ilas is used in These higher temperatures are more easily deformed or glazed. Generally speaking, i-t das (ilas with dei.i Above-mentioned composite area in the case of the » necessary heat treatment / generally resistant to the glazing.

Some examples of the implementation of the glass with a natural finish will now be described. The optical properties of the embodiment examples are described in connection with the devices with which the optical properties were measured.

Furthermore, are / are intended to explain the exemplary embodiments attached to the foundation / eichiuingen. Fs shows

· l "i g. I is a graph in which the reflection and ~ ° Durchlässigkcitseigensch.JtcM a singled out as an example erfindungsgemiiüen opal glass are plotted as a function of wavelength,

I i g. 2 a learning diagram. 111 the one for the Invention particularly suitable range of glass / assemblies / tingen is shown.

Γ i g. 3 is a diagram showing the interrelationships certain opaque glasses according to the invention are applied as a function of the wavelength are.

The difficulties encountered in measuring and comparing the optical properties of materials that tend to have an incident light beam / u diffuse (e.g., opalescent and opalescent (ilas), are known to occur. The basic problem is due to the fact that part of the radiant energy in the sample occurs, within which l'robe / is scattered from ordinary spectrophotometers is not detected as reflected, absorbed or transmitted radiation. The test procedure used in the Embodiment examples were used, attempts to 711 compensate for this scattering effect.

example 1

The source materials

Sand 3618.53 g

Raw dolomite lime 1414.88 g

high calcite lime 72.48 g

Alumina 323.83 g

Borax 175.63 g

Sodium carbonate 146.43 g

Potassium carbonate 85.18 g

55

ίο

(il / .: W

SiO,

CaO

Wed :().

\ a Λ>

Knockout

IU),

l'coO ;, (pollution)

I emperature for viscosity IO'Poise 'leniperalur for viscosity l () ^T Poise

I iqtiidtislcmperatur

Viscosity at l.i (| iiidiistempcratur. Rhernian expansion coefficient C- K) '(O to 30 (f C) ...

■> ι

)! (■ <( 1227 ■. Ι0 ^; '· Ίν

The glass cups are then at a tempi Uiι ν on SOO C for 24 hours in an electric; egg held. At the end of this period, the ibecher evenly opaque-opal. The remaining η

shafts of the glass (density, chemical resistance. ■ -it Coefficient of expansion) were not significantly changed by this \\,:; .ve treatment.

Example 2

Common materials were after the author.; ... ·. ·! of example embodiment 1 to a homogeneous ■ - :. r melted, the following composition: h Features has:

licsland part

SiO,

70.6

6.S ⁽ M 6.1 3.3 1.4

45

were in a crucible made of platinum at glass temperatures around 1600 C in an electric oven> o melted with mechanical stirring. The melting point was about 24 hours to ensure homogeneity. From the molten glass were after several glass beakers are produced using a conventional blow molding process. The finished glass cups were transparent and keep the appearance of ordinary soda lime glass cups and had the following composition and features:

CaO

MgO

Na ₂ O

K ₂ O

H ₂ O _{: 1}

FcoO.i (contamination) O.Od

Liquid temperature 1240 ° C

Thermal expansion

zieni / C-IO '(O to 300 C) ...... 56

The molten glass was sat in several small rectangular plates (25 x 19 x 3 mm). The tubes were clear and translucent after casting. Three of these plates were selected, and each of these plates was given a specific heat treatment in an electric laboratory oven. One of the plates was not subjected to any heat treatment and served as a comparison object.

Plate 1

Heat treatment: none.

Appearance: clear and transparent without being visible. Light scattering.

Heat treatment: 2 hours at 800 C Appearance: very light blue geeen an -ehwar / et Background, low cloudiness in "

I ¹ I, .lie

Heat handling: 2 hours Iv ι sill C.
Going out: clear blue ucgc :: a black! Background clear cloudiness.

I ¹ LiUc 4

Heat treatment: 2 .hours hot
Appearance: permanent opaque-opal.

'JIM / C

Lin the optical properties of the plate-1 further To characterize, reflection and transmission with respect to radiant energy were with spectrophological Average determined after the samples have been ground and polished to surface inaccuracies to remove. The spectral permeability were determined by means of a Hcokmann-Spek-Irophotomcters DK-2A determines that with an integrating Was equipped with a hollow sphere. in order to be able to better absorb the radiation that occurs. the hiirchlässigkcitsmessun; '. was obtained by that in parallel monochromatic light beam through which the robe was focused on a detector. The amount of energy (which was measured over a range of wavelengths of interest) was then expressed as a percentage recorded the amount of energy occurring on the sample. The integrating hollow sphere mentioned above > lmmcil those Anieil who ausai'.d'ep. Radiation. which due to scattering is not parallel to the incident Radiation escapes. This procedure removes almost all of the energy that is applied to the sample. recorded.

The reflection and transmission curves for the plate 4 as a function of the wavelength are shown in FIG E i g. 1 shown. These curves are characteristic of highly opaque-opal types of glass.

Embodiment 3

In order to further show the properties of the opal glass according to the invention, several samples were produced according to the glass composition of embodiment 2 for a density determination. The density of the clear, transparent glass was measured by conventional methods and was 2.4691 g / cm ³ . Similar samples of the same glass composition were heat-treated at 930 C for 21 hours. At the end of this heat treatment, the sample was uniformly opal. The density was 2.5591 g / cm ³ , which corresponds to an increase of approximately 3.6%.

Embodiment 4

Starting materials were ^{melted according to method 5d} of embodiment 1 to form a homogeneous glass of the following composition:

component
SiO, Gev. ichupro / x-nt
62.0 AlX) ₁ 6.0 CaO lü.d MuO 7 5 Well O 5.0 H..O, 9.0

\ on the melted GIa- became; ·. Rods. "gen. which one ar. -helpful in the surrounding air let cool. The rod was atifgcleilt in prehistoric sticks. which look clear and transparent here ..

Several of the prosthesis wands became hot for 64 hours : ■; '. «) C heat-treated. D.is the resulting glass was uniformly opal. The Routgenstrahl-Str ^ iibbild this opal glass indicated that significant amounts of the crystal diopside (CaO · MgO · 2SiO.) were present in the Surface were present. This means that the cilas conforming to the norm even with an extended one Heat treatment is devitrified (which applies to most types of glass), but that the presence of this Kiistallart does not harm the opacity.

Implementation example 5

Starting materials were made into a glass by following the procedure of Example 1 as follows Composition and properties melted:

UestamJleil percent by weight

SiO ₂ 68.8

ALO ₁₁ 6.4

CaO 11.3

MgO 7.3

Na ₂ O 4.0

K ₂ O -

B, O _a .. 2.4

Temperature at Viskosilä x 10 ^a poise 1293 "C
Temperature at viscosity 10 ⁷ poise 877 C

Liquidus temperature 1238 C

Viscosity at liquidus temperature. . UF- ³ PoJSe

The weight eiiK, SchmelztiegelTülliing was about 4.5 kg. and melting was in a refractory container at 1593 C in a gas-fired furnace Performed mechanically for 24 hours. Pro 'ist rods were drawn from the melt. The test sticks were clear and see-through. To determine the influence of the opal finish on the glass stability, were with the clear glass and the opal Glass fatigue strength tests carried out. The standard US Pharmacopeia XVII procedure was used used. This procedure will wit Olgi Designated: United States Pharmacopeia XVlI, Cpn-Uiiners-glass. chemical resistance-wcter-attack.

The procedure corresponds to the powdered glass test ASTM regulation C-225-59T (Method P. W. 'Resistance of Powdered Sample to Attack by Distilled Water).

Generally speaking, the procedure is. to produce an extract of a glass powder sample with a given volume of water at an elevated temperature for a certain period of time. At the end of this period, the water is _{titrated with 1/50 H 2} SO to the neutral point in order to neutralize the powdered glass extract. The test results are given in millimeters of required NO H ₂ SO. The lower the number of ml of // 50 H ₂ SO, the worse the chemical resistance.

The following test results were obtained: The clear and transparent test rods required 1.8 ml. H / 50 HoSO ₁ and the opaque-opal test rods after a heat treatment for 10 hours at SOO C) 2.5 ml. «.50 H ₂ SO ,. to neutralize the water output. This shows that the chemical Rv--

13th

component
SiO.,

Cab ...
MgO. . .
N a., O. .
K "Ö.
BJC),

Cicuichis percent Λ 6B (if

Iy-). ~ 69.8 64th N.

6.3 6.2 Λ.Τ

10.6 ill.6 Π.2

7.3 7.4 7.S 3.0 5.0 3.7

2. ^c > ! .0 ^ς >

Temperature C

: 22 ^l > 13 '[S! 251 S-7 ⁷

Temperature is called viscosity

KV [ ⁵ OiSC

Temperature hci viscosity

10 ^: Poise

l.iqiiidiisiempc ^r ; iuir 1331 1248 1215

Viscosity for Liquidtis-

tcmperature (Poise I...
Time 1 hour

Time 64 hours

UV ¹ · "ΙΟ- ³ · ¹ lü- ¹ · - 800 no 710 opalescence

725 720 "675

Maturity towards water due to the opalescent Heat treatment is not significantly reduced.

Execute! example 6

According to the procedure of the implementation example ϊ were made from iced Aiiscangsin lU-rulien compositions 6.Λ. ή H and '■'. ' (-. lines ι melted. uid from the melt were clear, translucent Test stick ic / ogen. Experiments were carried out. to set the minimum time temperature in the case of opalescence emiriit. The one listed below! Times and temperatures are those given Times of minimum temperatures at which the Glas7üsammciT> etzu: i !: slightly cloudy or; becomes milky ·· w ith.

H e ι s ρ ι e!

To

The! .Ψ-eiuicn values illustrate exactly the uezieium-j.-ui-eii.-n of heat treatment and dei Z:; s.i; "Pieiise! /. Ii '^ ^ i tmdungsgLiiiäb'er Glasarten.

Ci! .ii - ,; t of the following to -: 'inmenseiz.imgwMrdenachdem \ experienced de- Execution.mgshcispiHs 1 from suitable Aiisiiar'üsnr.itcriaiien melted, and from dei Melt were rods 12 "cm long and slightly. 0.6 cm diameter drawn. The appearance of the> et Rods was registered.

P: "After that, the bars were treated by the armed forces. determine the following temperatures:

Tu i: lowest temperature at which after eir. ^ R Stun.de "heat treatment a light; opalescence (weak turbidity) is visible: lowest temperature at which according to cmc; Hour "heat treatment of a dense white, - opal glass arises:

Tu 64: lowest temperature at which after e; u -, Heat treatment for 64 hours ■ · .. · ■. · weak opales / enz is visible:

, - To 64: lowest temperature at which after e ,;

° Heat treatment of 64 hours a you;. ·

white opal glass is created.

This determined these temperatures. J.

the rods in a gradient furnace with a rod:!. If the temperature profile was inserted during the specified period. Since the Gnidien.enofc ι ei: known uniform temperature gradients. ■■: about 350 C over the length of the rod, the exact temperature for each point on the rod was known; _: . The measurements are listed in Table 1

table

AUO ₃ OK Gl jszi! composition Cu (J MgO B.O., Look Do 1 Tu. M Ti) 1 Tn f. 2 3 12.9 9.1 0 the stick (C) (C) ('C) ('C No. 2 [ 5 11.7 8.3 9 after naeh after riiici 2 5 in Cieu ichtspro / ducks 10.6 7.4 2 opal 1 hour MSumden 1 hour 64StUr ₁ 7-1 2 5 SiO, 9.4 6.6 4th clear 7-2 2 5 73.0 10.6 7.4 6th clear 810 725 * 7-3 ■ 2 ί 5 73.0 11.7 8.3 S. opalescent 760 675 * * 7-4 2 ί 5 73.0 8.2 5.8 10 opalescent * 7-5 2 7th 73.0 9.4 6.6 opalescent * ΐ 7-6 2 ! 7th 69.0 7.0 5.0 • 6 opalescent 800 730 7-7 2 '7 65.0 7.0 5.0 10 clear - 780 740 7-8 4th ί 1 69.0 15.3 10.7 0 clear + * 7-9 4th 3 73.0 14.1 9.9 0 clear * 690 * * 7-10 4th 3 73.0 12.9 9.1 1 opal 750 675 * * 7-11 4th 3 69.0 11.7 8.3 4th clear - 7-12 4th ■ 3 69.0 15.3 10.7 6th opalescent 720 690 * 780 7-13 4th ■ 5 69.0 lo.ii 7.4 0 opalescent 775 7-14 4th S. 69.0 10.6 7.4 4th clear 7-15 4th 5 69.0 12. ') 9.1 7th clear * 715 * - 7 ■ 16 4th ς 61.0 8.2 5.8 ! ■ clear * 720 * 8 (X) 7-17 4th 7th 73.0 5.3 3.7 10 clear 780 710 * 760 7-18 4th • 7 69.0 5.9 4.1 14th opalescent 750 700 SK) 750 7-19 62.0 klai 740 725 7-20 65.0 clear + 680 730 7-21 70. (1 725-775 670 690 65.0

ίϋ

AUO ₂ Gl Na ₁ O CjCU i mensel / '. i; ^ MuO 0.5 Look ι
I. Do I. - - Do 64 - To 1 I. 925 To 64 Sr I 6th in 0 7.4 ΟΛ I the bars opal j ι-C) - ( ^e C) - I O 90f) j (C) I. 6th 1.5 SiO. 7.4 1.5 opalescent j me - after - after 9 ¹ O after H 1.5 7 * ■> s y.v 4.5 opalescent! 1 hour J 820! 64hours 1 hour I. , s 50 4 hours * ~ * ~ I 6th 1.5 74.0 :(: ■ 6 7.4 7.5! opal ' I. 840 j 730 - 800 - -> "^! 6th 1.5 67.0 Ίΐ. · .6 7.4 0.5 \ opal; 825 700 - "> 1 i 6th 3 70.0 14.1 ⁷ .4 1.5! kiar j - 680 - 810 _ ¹ ^ ^ ■ 6th 3 67.0 ΪΟ.6 7.4 3 y clear j - - 880 - -Io i 6th 3 72.5 10.6 7.4 4.5! clear - - - -26ai 6th 3 '1 ^ '0.6 7.4 6th opalescent - - * 800 - * 7 y 6th 3 70.0 io.6 7.4 ;. : · opalescent 775 - * 775 -2S I 6th 3 6S.5 ! 0.6 7.4 9 v) |) al - 710 * 760 -2v 6th 3 67.0 10.6 7.4. 6th opal * - * - 6th 3 66.5 10.6 11.2 12th Clear * 720 825 - 7 - 31 6th 3 (4.0 10.6 9.9 0 opal 800 720 800 - 6th 5 58.0 10.6 - 1.5 clear 760 700 810 - 6th 5 55/1 1 5.8 7.4 clear 750 680 800 760 ': I 6th 71.0 1-4.1 7.4 4.5 clear 740 670 * - - * .ς 6th 5 69.5 1C.6 7.4 6th clear 760 600 790 "- 3 6 6th 5 68.0 i0.6 7.4 / S clear 740 655 825 775 6: 5 66.5 10.6 7.4 9 clear 760 640 750 · '- 3 pp 6: 5 65.0 i (i.6 7.4 10.5 clear - 700 * 740 "- 9 6 ^; 5 63.5 10.6 7.4 5 clear 750 - * 720 ; -40 6th 5 63.0 10.6 7.4 12th clear 750 680 700 710 7-41 5 5 60.5 10.6 7.4 6th opalescent * 670 * 700 7-42 6th 5 66.0 10.6 5.0 10 kl Ji- 670 * 690 5 59.0 10.6 4.1 6th clear 710 675 740 7-44 6th 7th 71.0 10.6 3.3 8th clear * 670 875 670 1-45 6th 7th 69.0 7.0 5.8 14th clear * 660 * 740 7-46 6th 7th 73.0 5.9 5.0 4th clear S50 680 * 725 7-47 6th 9 65.0 : -4.7 6.6 6th clear 800 740 - 700 7-4S 6th 9 61.0 X.2 5.8 2 clear 785 725 * * "-49 8th 3 65.0 7.0 6.6 6th clear 775 790 790 * 7-50 C.
v> 3 65.0 9.4 7.4 10 clear 830 775 * 700 "-51 8th 3 71.0 8.2 3.3 14th clear * 690 785 725 7-52 8th 3 65.0 9.4 3.3 6th clear 760 750 800 7-53 10 3 71.0 10.6 5.8 10 clear * 710 740 7-54 10 3 67.0 4.7 4.1 14th clear 740 730 * 7-55 10 3 67.0 4.7 7.4 6th clear 690 * 7-56 10 5 67.0 P.2 6.6 ι 14th clear 775 7-57 10 5 55.0 5.9 6.6 clear * 7-58 63.0 10.6 730 7-59 55.0 9.4 770 7-60 9.4 720

Notes: · means that Op: cancellation did not occur under the search conditions. - means that the special usage conditions were not evaluated.

Hin glass within the erfiruhmcsgemäüen Zusammensctzungsbereichs whose components have approximately the following percentages by weight, oesit / t konimcr / iell 6o desirable "ormcigeii ^ chafien as ViskosiUil-1 empcraUir-Beziehiing. Lii] uidiistemper, uur and thermal Aiisdehnungsvcrmiipeii, can consist \ erhaltnisinäliig cheap AusgangsniaU 'rialien are heruesielll, hesi' ./ i line chemical resistance and can be opalesced during a modid / ierlcn warmth treatment pro / eU

Hcstandtcil weight percent

SiO ₂ 66 to 69

ALO., About h

IU) .. 4 to 8

RO (CaO; MgO) 13 to 18

NaX) elw. 1 5

CaO (iewiclitspnventc,,

¹ about 1.4

MnO C ievuchispro / duck

1 909 1S7

1566 C. 1316 C. 927 C. 1204 C. 112 C. 60 · 10

This glass has the following properties:

Temperature at viscosity 10 ² Poisc ...
Temperature at \ is'.ciiät iO'Poise
Temperature at viscosity 10 ^T poise. . .

Liquidus temperature ■

Temperature at visco> iiäi i0 ^J (C)

- Liquidusten raiur ι C) ■

Thermal expansion coefficient

300 C)

Preferred compositions within the above range are shown in FIG. 2 shown. DoIomitkalk was used as a source for CaO and MgO, so that the weight ratio CaO to McO is about 1.4. The preferred types of glasses are those types of glasses represented by the parallelogram in the middle part of the ternary diagram. The boundaries of this parallelogram were determined by evaluating the glass forming and relaxation properties in view of the heat treatment required for opalescence. Glass within this preferred composition range has excellent molding properties and becomes thermally opalescent in a very short time at a relatively low temperature. It has been found that articles molded from oils with these compositions - in a modified relaxation mode can be opalesced. In these glass compositions, H ₂ O _{3 is} the primary opalescent agent and the tendency of the glass to opalesce increases as the proportion of B ₂ O increases.

The time and temperature for the opalescent heat treatment this glass agrees with the stress relief heat treatment of conventional lightweight glass articles. This means that this type of glass through a heat treatment at temperatures of about 565 to 845 C in 15 minutes to about 5 hours can. Preferably the opalescent heat treatment for economic reasons at temperatures between 760 and .S15 C for about one Run hour.

The following tables indicate glass compositions which are within this preferred composition range, depending on the B ₂ O ₃ component:

Β, Ο, -Anreil is
lk- <K.ndteil
N: 1 _; O

a S%:

about 6 66 to 6s 13 to 1-

SiO ₂

RO (CaO; MgO)

These types of glass do not require any special Sch; 0 ..- I ₂ . and LäuicrLingsbedingungen and can be melted in continuously operated gas-fired furnaces at tempering \ .1 1425 to 16 (X) C. :). Ihei can \ use common original materials, as shown in the following examples \ or_ _{: c} ht.

Embodiment example p

The raw materials

powdered flint 3967.94:

raw doloniite lime 2069.30 ::

Soda ash 517.24 ^

Boric acid appendage 314.47:

Alumina 362.17; '

are in a platinum crucible at a; ; v temneratur of 1593 C in an electric ^! .n melted with mechanical stirring. ', c melt line is about 14 hours to Hom <;. \ - to ensure.

A rod $ was made from the molten glass. gen. from which test rods were formed, the r.i: ■ η Cool down the ambient air Iiei3. The rehearsal v.

clear and transparent and had the following sffzuna:

Hcslandleil
SiO ₂ .

AI ₂ O,
CaO. . .
MgO. .
Na ₂ O.

Weight percentage:

66.0

6.0

10.0

7.5

5.0

5.0

i-part is about 4 ° / ":

component Weight percent Weight percent Na ₂ O about 5 about 5 AI ₂ O, about 6 about 6 SiO ₂ 67 to 69 / _ /: r 1, ■ ' ■ · - RO (CaO MgO) 16 to 1 « B ₂ O ₃ -AnICiI about 6 "/ _n : component Na ₂ O AI ₂ O, SiO.,.

KO (CaO _: MgOi. ... 14.5 to 16.5) Several of these rods were heat-treated for a long time at 815 C for 15 min.

; o cloudy). The coefficient of thermal expansion in the temperature range from 0 to 300 C was measured using conventional methods and was about 59.6-10 TC.
Other test bars of the same composition would be heat treated at 815 ° C for 16 hours. At the end of this heat treatment, the test rods were uniformly opal and the coefficient of thermal expansion was 60.4 · 10 '/ -C (Obis300 C). This means an increase in the thermal Ain-

SSO dehnungskoeflizienten ^\: on about 1.3%.

Example 9

From the composition according to the exemplary embodiment As a result, clear, transparent test panels about 1.8 mm thick were produced by melting the Glass was poured in the open air in a shallow, fireproof pan. The plates were

divorced grandpa

izzierung !, - heat handler, subjected, in order to be able to carry out reflection measurements.

The heat treatment and the appearance of the sample panels are described below. The optical one Reflection of the radiant energy in the visible wavelength range was determined by conventional photometric Procedure determined. The results are in F i g. 3 shown graphically.

Plate 1

Heat treatment: none.
Appearance: clear and transparent.

Plate 2

Heat treatment: half an hour at 815 C, Appearance: slight opalescence.

Temperature at viscosity 10 ² poise 1527 C
Temperature at YiskoMtät lO'Poise I27-TC
Temperature at viscosity ICF- ^ poise 846 C

Liquid temperature 1177 C

Temperature at viscosity 10 ^{: i}

- Liquidus temperature 97 v_ "

Thermal expansion coefficient 58 - ^{10 7 -}

(0 to 300

Plate 3

Heat treatment: one hour with Si5 Appearance: slight opalescence.

C.

Plate 4

Heat treatment: eight hours at S15 C. Appearance: almost opaque-opal.

Plate 5

Heat treatment: two hours at 827 C, appearance: opaque-opal.

Relaxation tests were carried out with these test bars and it was found that the test bars were slightly opalescent after one hour at 749 "C. Further tests with bars of this composition were carried out and it was found that the bars after a heat treatment of one hour became densely opaque-opal at 821 C. This shows that the relaxation and opalescence treatment can be combined. With certain glass compositions it is even possible to dispense with a subsequent heat treatment entirely and opalescence ⁷ under the simple influence of the thermal condition that exists in casting. These types of glass are also characterized by low coefficients of expansion and good chemical resistance.
They correspond to the composition:

Weight percent

SiO ₂ about 71

Al ₂ O ₃ about 4

RO (CaO -f MgO) about 10

B ₂ O-, about 12

Na ₂ O about 3

the weight ratio of CaO to MgO being 35. These probeplatu.-n were ground and polished, this ratio is for the properties of the GIase>

L J: AL- η- ι < ·

until the surface was smooth, and the optical reflective properties were conventionally made using a General Electric "Hardy" model spectrophotomer with a black background definitely. The results are shown in FIG. 3 shown. These curves show how the time duration and The temperature of the heat treatment can be changed to achieve the desired optical properties to achieve in the glass according to the invention.

the most favorable and advantageously corresponds to the most favorable and advantageously corresponds approximately to the ratio of lime and magnesium approximately to the ratio of lime and magnesia in dolomite. In addition, other alkali metal oxides can be used in place of sodium oxide, although lithium oxide promotes discharge at high temperatures.
These types of glass have the following properties:

Embodiment 10

According to the method of the embodiment · · 8 raw materials were melted and sample bars manufactured. The glass had the following composition and properties:

Temperature at viscosity 10 ² poise 165OC

Melting temperature 1127 ° C

Viscosity at melting temperature 10 ⁴ - ² poise
Expansion coefficient per T

(between 0 and 300 C) <45

SiO,

CaO.

Na-O
IU), ..

Weight percent

Opalescence of the glass occurs over a range of temperatures ρ η, which is suitable for the forming processes,

and is completely expired when the glass transition temperature reaches the Littleton point (viscosity IQ7.65 p _o j _se ) during cooling. Otherwise the opalescence develops during the molding process; it occurs instantly when the molten glass enters the

free air is drawn.

1 sheet of drawings

Claims (7)

Patent to> prui.ne: 1. Procedure for the 1! Cr ^ -determination of Opaiglaseege v stands. thus ρ e k e η π / e i c h η e t. that from an [Irdalkali-Ahiminiumsiükat-Glas. that contains the following Bes'.ai'.dieile. component Gc-A ichispri > show SiC). 55 bi, ⁿ h ALO, until \ 2 Bi) ₁ O until 13th CaO 5 until 20th McO O until 15th Well, O 1 to ■ H K, Ö O until 5 ! .J ₂ O O until ■> with the conditions (CaO r MgO) 10 until 30th (Na ₂ O ■ K ₂ O) ■ - '. L1 Weight percent B ₂ O., until 5 Weight percent Na ₂ O (SlO.,; AI, O,; l!, 0 _{: 1} : CaO - MgO ■ Na ₂ O) - ^{:> 1} '5 the glass objects are formed and by a Heat treatment an iM-siti! -Ph: «scn! Rcnnung 3" brought about \\. ir «J. dun.h die the C'asccgenstänil: opales / eni north. 2. The method according to claim I, characterized in that that a glass is used which contains the foleenclen components: component Weight percent ■ Φ until < 70 SiO. . . 60 until S. AI ₂ O,. . . . . . 4th until <) B ₂ O ₃ . . . . ! until 16 Ca () . . . 6th until 12th MaC) . . 4th until 7th Na ₂ O . . . 3 with the conditions until 21 (CaO f MgC) ") 14th (Na ₂ O: K ₂ O). . . . . ■ S (iewichtspuventi to 3 Weight percent (SiO.,; Ai-O ₁ : aC ! MuO \ a, O; gene * BA, ₀ , Na ₂ O B ₂ O _: ,: C 3. The method according to claim I, characterized in that that a (has \ used that the foiuerillen Components contains: i tukeil SiO,
AI ₁ O ,.
IU),
CaO
Nj ₂ O.
with the UiVi 6
4 to p 13 to IS
at 5'o clock 'e (a ()
ie MuO lind has the following properties: Temperature at viscosity K) ¹ poisex ·. 1316 C Liquidus temperature! 204 C Temperature at viscosity
IG ³ poise ί C) - liquid temperature (C) II-C Therm. Expansion coefficient ". -: 60-10 ⁷ C (O to 300 C) 4. The method according to claim 3, characterized in that that a glass is used which contains the following components: Part of Geuicht.sp.ozent SiO ₂ 67 to 6 ¹ ) A1., O _{; 1} at 6 B ₁ Or, at 4 CaO ^; MgO 16 to 18 Na ₂ O at 5 5. The method according to claim 3, characterized in that that a glass is used which contains the following components: iicsuiidteii Weight percent SiO, 66.5 to 68.5 AKO, . . . at 6 B ₂ O ₃ at 6 CaO I-MgO 14.5 to 16.5 OK at 5'o clock 6. The method according to claim 3, characterized in that that a glass is used which contains the following components: Ho «t; ir.dleil
SiO,
ALC) ₃ .
B ₂ CV. CaO · MgO Well, O ... " Weight percent 66 to 68 at 6 at 8 13 to 15 at 5'o clock 7. The method according to claim 3, characterized in that that a glass has been used to cover the foils Components contains: Hi-stanJ part
SiO ₂
Ö CaO ...
MaO ...
Na ₂ O. .
IU) ₁₁ Weight percentage 67 6.7 ■ in the i .4 uiiü has approximately the following properties: Temperature at viscosity 10- poise Temperature at viscosity IO 'poise oil temperature at viscosity 10 ^{Ti (i: i} poise Liqiikliistemperatiir Temperature at \ iskosiiäi
10 'poise l.iquitiisiempera- T Il Γ I hernial expansion coefficient . . 527 C. 274 c P. 46 C. 177 C. ¹ C .v-10 ' C in to 100 C ¹ K. »'experienced according to claim, i. dad! rc! ι uckenn / cichnei. that a GIa-; used will. da- \ lie "ol- send components contains: icsla-ciei! CiC i ^ ^: .-spi.izc-m so., -ti M..O 4th B, Ö, ι ι
1 - CaO MoO . in MUIioxide with a * ratio of Ί ^ς
MgO and approximately the following t.igenscliaften hat: ■ 650 C 1 . 27 C component SiO., AU), B, Ö, CaO · MgO. . .
Alkr'ioxide 55 ni ·, 75.5
2 hi. Ό
ο to! 2 in to 26
0 to 3