Title of Invention

A PROCESS FOR PREPARING A BOROSILICATE GLASS OF HIGH CHEMICAL RESISTANCE AND LOW VISCOSITY

Abstract The invention relates to a process for preparing borosilicate glass of high chemical" resistance and low viscosity which contains zirconium oxide and lithium oxide, having class 1 hydrolytic resistance, in accordance with DIN ISO 719, class 1 acid resistance, in accordance with DIN 12116, and class 1 caustic lye resistance, in accordance with DIN ISO 659, and with a low working point VA of between 1180°C to 1230°C and a coefficient of thermal expansion oc20/300 of 4.9 x 10-6 K-1, with the composition (in % by weight, based on oxide) : SiO2 73.0 -75.0; B2O3 7.0 -10.0; Al2O3 5.0 -7.0; zrO2 1.0 -3.0; Li2O 0.5 -1.5; Na20 0 -10.0; K2O 0 -10.0; MgO 0- 3.0; CaO 0 -3.0; BaO 0 -3.0; SrO 0 -3.0; ZnO 0 -3.0; SiO2/B2O3 ratio ~7 .5; L SiO2+AI2O3+ZrO2 80.0 -83.0; L MgO+CaO+BaO+SrO+ZnO ~3.0 and Fluorides 0- 3. The glass is particularly suitable for use as a versatile primary packaging mat~rial for pharmaceuticals, for example as ampoule glass.
Full Text

The present invention relates to a process for preparing borosilicate glass of high chemical resistance and low viscosity.
For use as primary packaging material, for example as ampoule glass, the pharmaceutical industry requires glasses having extremely high chemicals resistance. The commercial pharmaceutical ampoule glasses known hitherto are in hydrolytic resistance class (H) 1 (in accordance with DIN ISO 719), acid resistance class (S) 1 (in accordance with DIN 12116) and caustic lye resistance class (L) 2 (in accordance with DIN ISO 695) . This prior art is represented by the glass Fiolax® clear, Code No. 8412 Si02 74.7; B203 10.0; Al303 5.0; Na20 6.5; CaO 1.5; BaO 2.0; fluorides 0.3% by weight) and JENA instrument glass Ggl 490/5 (Si02 73.2; B203 11.0; A1203 5.3; Na20 7.0; K20 0.2; CaO 0.8; BaO 2.5% by weight) , which have a weight loss of 100 mg/dm2 (in accordance with DIN ISO 695) . A class 1 caustic lye resistance, i.e. a weight loss of However, an important requirement in the pharmaceuticals industry is the provision of primary packaging materials having significantly improved caustic lye resistance to enable packaging of recently developed injections which exert, stronger basic attack on the contents. Practical experience has shown that safeguarding of the caustic lye resistance in the production process requires the development of glasses in the laboratory having weight losses of less than 65 to 70 mg/dm2, i.e. safely within caustic lye class 1.
Naturally, the achievement of this requirement must not impair the other important glass and glass; production properties. For example, H = 1 and S = 1 must

Thus, at an a value o£ approx. 4.y x _LU w K~~, an excellent chemicals resistance of H = 1, S = 1 and-L = 1 (weight loss Since CaO has a stabilizing action on the acid resistance# small amounts should be possible in the glass if possible. Small amounts of BaO are likewise helpful in order to further reduce the viscosity and to lower the melting point. On the other hand, it may also be necessary for the glass to contain only very little BaO and CaO, or none at all, since it is known that these components can react in an undesired manner with some specific inj ection solutions.
If the respective pharmaceutical and industrial areas of application do not make the highest demands regarding chemicals resistance, the glass properties can be further modified by addition of the further bivalent components SrO, MgO and ZnO and by varying the CaO and BaO contents.
However, their total content must remain restricted to a maximum of 3.0% by weight, through which the novel composition differs from the composition disclosed in DE 42 3 0 607 CI (E MgO + CaO + BaO + ZnO + SrO + Zr02 = 6 to 10 = E MgO + CaO + BaO + ZnO + SrO = 3 to 9.5 if Zr02 « 0.5 to 3).
In addition, small amounts of fluorides can be added to the novel glass compositions in order to accelerate melting or to reduce the viscosity further, or known refining agents, such as chlorides and Sb203, can be added.

Accordingly, the present invention provides a process for preparing borosilicate glass of high chemical resistance low viscosity comprising the steps of batch formulation, melting refining, homogenization and conditioning of glass followed by hot forming, wherein the glass formed has a composition of
Si02 73.0 - 75.0
B203 7.0 - 10.0
A1203 5.0 - 7.0
Zr02 1.0 - 3.0
Li20 0.5 - 1.5
Na20 0 - 10.0
K20 0 - 10.0
MgO 0 - 3.0
CaO 0 - 3.0
BaO 0 - 3.0
SrO 0 - 3.0
ZnO 0 - 3.0
Fluorides 0 - 3.0
with
Si02/B203 >7.5
2 Si02+Al203+Zr02 80.0 - 83.0
S MgO+CaO+BaO+SrO+ZnO in percentage by weight based on oxides.
Working Examples:
Table 1 shows novel glass compositions and their essential properties relating to the invention.
It can be seen that, if the defined coefficient of thermal expansion of oc20/300 =
4.9 x 10"6 K"1 is observed, the caustic lye resistance L, expressed by low weight loss
values of from 58 to 65 mg/dm , is very safely within class 1, and the working points
are low, with VA —-—-—-—.



WE CLAIM:
1. A process for preparing borosilicate glass of high chemical resistance low
viscosity comprising the steps of batch formulation, melting refining,
homogenization and conditioning of glass followed by hot forming, wherein
the glass formed has a composition of
Si02 73.0 - 75.0
B203 7.0 - 10.0
A1203 5.0 - 7.0
Zr02 1.0 - 3.0
Li20 0.5 - 1.5
Na20 0 - 10.0
K20 0 - 10.0
MgO 0 - 3.0
CaO 0 - 3.0
BaO 0 - 3.0
SrO 0 - 3.0
ZnO 0 - 3.0
Fluorides 0 - 3.0
with
Si02/B203 >7.5
Z Si02+Al203+Zr02 80.0 - 83.0
I MgO+CaO+BaO+SrO+ZnO in percentage by weight based on oxides.

The process as claimed in claim 1, wherein said borosilicate glass has a
composition (in % by weight, based on oxide), of
Si02 73.0 - 75.0
B203 8.0 - 10.0
A1203 5.0 - 6.0
Zr02 1.0 - 2.0
Li20 0.5 - 1.5
Na20 0-10.0
K20 0 - 10.0
MgO 0 - 3.0
CaO 0-3.0
BaO 0 - 3.0
SrO 0 - 3.0
ZnO 0 - 3.0
with
Si02/B203 >7.5
I Si02+Al203+Zr02 80.0 - 83.0
I Li20+Na20+K20 7.0 - 10.0
I MgO+CaO+BaO+SrO+ZnO The process as claimed in claim 1 or claim 2 wherein said borosilicate glass has
composition (in % by weight on oxide), of
Si02 73.5 - 75.0
B203 8.0 - 10.0
A1203 5.0 - 6.0
Zr02 1.0 - 2.5
Li20 0.5 - 1.5

Na20 0.5 - 5.0
K20 0.5 - 5.0
CaO 0.5 - 2.0
with
Si02/B203 >7.5
I Si02+Al203+Zr02 81.0 - 83.0
S Li20+Na20+K20 7.0 - 9.5
The process as claimed in claims 1 or 2 wherein said borosilicate glass has a
composition (in % by weight, based on oxide), of
Si02 73.5 - 75.0
B203 8.0 - 10.0
A1203 5.0 - 6.0
Zr02 1.0 - 2.5
Li20 0.5 - 1.5
Na20 0 - 3.0
K20 4.0 - 7.0
with
Si02/B203 >7.5
S Si02+Al203+Zr02 81.0 - 83.0
Z Li20+Na20+K20 7.0 - 10.0
The process as claimed in any of claims 1 to 3, wherein said borosilicate glass
has a composition (in % by weight, based on oxide), of
Si02 74.0 - 74.5
B203 8.5 - 9.5
A1,(X 5.3 - 6.0

Zr02 1.6 - 2.0
Li20 0.7 - 1.3
Na20 3.0 - 5.0
K20 2.0 - 5.0
CaO 0.5 - 1.6
with
2 Si02+Al203+Zr02 81.3 - 82.0
2 Li20+Na20+K20 7.0 - 9.5
. The process as claimed in claim 5 wherein said borosilicate glass has a
composition (in % by weight, based on oxide), of
Si02 74.0 - 74.5
B203 9.0 - 9.5
A1203 5.3 - 5.8
Zr02 1.6 - 2.0
Li20 0.9 - 1.1
Na20 3.0 - 5.0
K20 2.0 - 4.0
CaO 0.8 - 1.2
with
I Si02+Al203+Zr02 81.3 - 82.0
I Li20+Na20+K20 7.0 - 9.0

7. A process for preparing borosilicate glass of high chemical resistance low viscosity substantially as herein described and exemplified.


Documents:

1482-mas-1996-abstract.pdf

1482-mas-1996-claims duplicate.pdf

1482-mas-1996-claims original.pdf

1482-mas-1996-correspondance others.pdf

1482-mas-1996-correspondance po.pdf

1482-mas-1996-description complete duplicate.pdf

1482-mas-1996-description complete original.pdf

1482-mas-1996-form 1.pdf

1482-mas-1996-form 26.pdf

1482-mas-1996-form 3.pdf

1482-mas-1996-form 4.pdf


Patent Number 207256
Indian Patent Application Number 1482/MAS/1996
PG Journal Number 26/2007
Publication Date 29-Jun-2007
Grant Date 01-Jun-2007
Date of Filing 22-Aug-1996
Name of Patentee SCHOTT-ROHRGLAS GMBH
Applicant Address THEODOR-SCHMIDT-STRABE 25, 95448 BAYREUTH.
Inventors:
# Inventor's Name Inventor's Address
1 SCHOTT-ROHRGLAS GMBH THEODOR-SCHMIDT-STRABE 25, 95448 BAYREUTH.
PCT International Classification Number C0303/093
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 195 36 708,1-45 1995-09-30 Germany