Method for producing a glass article

Abstract

A method for producing a glass article having high hydrolytic resistance is provided. A glass tube consisting of borosilicate glass and having an Al.sub.2O.sub.3 content of less than 1 weight-%, a ZrO.sub.2 content of 2-12 weight-%, and a glass transition temperature T.sub.g is reshaped into a glass article and is subsequently subjected to a thermal post-treatment. To reduce the alkali release of the glass article, the glass article is subjected to a treatment temperature of T.sub.B≥T.sub.g+5° K over a treatment time of t.sub.B≥5 min and is subsequently cooled during the thermal post-treatment.

Claims

1. A glass article, consisting of: a thermally treated borosilicate glass having an Al.sub.2O.sub.3 content of less than 1 weight-% and a ZrO.sub.2 content of 2-12 weight-%, the glass article having an alkali release of A≤0.5 mg/l Na.sub.2O equivalency according to ISO 4802 or an alkali release A≤3 mg/l Na.sub.2O equivalency according to USP 660 (glass grains) or ISO 720 (glass grains), wherein the glass of the glass article has a glass transition temperature T.sub.g, wherein the glass article is thermally treated by subjecting the glass article to a treatment temperature of T.sub.B≥T.sub.g+5° K over a treatment time of t.sub.b≥5 min and subsequently cooling the glass article.

2. The glass article of claim 1, wherein the glass article is in the embodiment of a small glass bottle, a glass vial, an ampoule, a glass ampoule, a cylindrical ampoule, a cartridge, a syringe body, a rod, an internal constructed tubular object, an external constructed tubular object, a tube, a semi-finished product to produce one of the aforementioned articles, or glass grains produced according to USP 660.

3. The glass article of claim 1, wherein the glass article has an alkali release A that is ≥15% less compared to an untreated reference glass article of the same composition.

4. The glass article of claim 1, wherein the borosilicate glass consists of the following composition: TABLE-US-00006 SiO.sub.2 60-78 weight -%; B.sub.2O.sub.3 7-20 weight -%; Li.sub.2O 0-2 weight -%; Na.sub.2O 0-6.5 weight -%; K.sub.2O 2.5-12 weight -%; ZnO 0-2 weight -%; ZrO.sub.2 2-12 weight -%; refining agent 0-1 weight -%; Al.sub.2O.sub.3 <1 weight -%; and unavoidable contaminants.

5. The glass article of claim 1, wherein the borosilicate glass consists of the following composition: TABLE-US-00007 SiO.sub.2 60-78 weight -%; B.sub.2O.sub.3 7-20 weight -%; Li.sub.2O 0-2 weight -%; Na.sub.2O 0-6.5 weight -%; K.sub.2O 2.5-12 weight -%; ZnO 0-2 weight -%; ZrO.sub.2 2-12 weight -%; refining agent 0-1 weight -%; Al.sub.2O.sub.3 <1 weight -%; at least one of MgO, CaO, BaO, TiO.sub.2, or SrO with a total of <2 weight -%; and unavoidable contaminants.

6. The glass article of claim 1, wherein the glass article is a storage container for pharmaceutical substances.

7. The glass article of claim 1, wherein the glass article has an alkali release A that is ≥40% less compared to an untreated reference glass article of the same composition.

8. The glass article of claim 7, wherein the glass article has an alkali release A that is ≥50% less compared to an untreated reference glass article of the same composition.

9. The glass article of claim 1, wherein the borosilicate glass comprises the following composition: TABLE-US-00008 SiO.sub.2 60-78 weight -%; B.sub.2O.sub.3 7-20 weight -%; Li.sub.2O 0-2 weight -%; Na.sub.2O 0-6.5 weight -%; K.sub.2O 2.5-12 weight -%; ZnO 0-2 weight -%; ZrO.sub.2 2-12 weight -%; refining agent 0-1 weight -%; Al.sub.2O.sub.3 <1 weight -%; and unavoidable contaminants.

10. The glass article of claim 9, wherein the glass comprises 9-20 weight-% B.sub.2O.sub.3.

11. The glass article of claim 9, wherein the glass comprises >0-6.5 weight-% Na.sub.2O.

12. The glass article of claim 9, wherein the glass comprises 4-12 weight-% K.sub.2O.

13. The glass article of claim 9, wherein the glass comprises 5-12 weight-% ZrO.sub.2.

14. The glass article of claim 1, wherein the glass is aluminum-free.

15. The glass article of claim 1, wherein the glass has a glass transition temperature T.sub.g of 500° C.≤T.sub.g≤620° C.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Exemplary embodiments provided according to the present disclosure are described further herein.

(2) TABLE-US-00003 TABLE 1 Factor A1 A2 A3 A4 A5 SiO.sub.2 [weight-%] 72.75 69.17 73.33 70.77 76.16 B.sub.2O.sub.3 [weight-%] 10.12 9.12 10.12 16.52 12.42 Al.sub.2O.sub.3 [weight-%] 0.15 0.18 0.08 0.11 Li.sub.2O [weight-%] 0.39 0.67 0.3 Na.sub.2O [weight-%] 2.8 2.02 2.86 0.99 0.71 K.sub.2O [weight-%] 6.21 10.32 6.1 7.19 4.65 MgO [weight-%] CaO [weight-%] BaO [weight-%] ZnO [weight-%] 0.82 ZrO.sub.2 [weight-%] 7.89 8.7 7.43 2.79 5.76 F [weight-%] Cl [weight-%] 0.08 0.1 0.08 0.14 Sum total [weight-%] 100 100 100 100 100 CTE [10.sup.−6/K] 4.7 5.3 4.7 5.1 n.d. T.sub.g [° C.] 585 560 585 505 530 Ew [° C.] n.d n.d 785 725 n.d. VA [° C.] 1215 1180 1210 1060 n.d. First measurement Li.sub.2O [mg/l] 2.07 0.32 5.87 0.37 Na.sub.2O [mg/l] 1 0.33 1.71 2.57 8 0.85 K.sub.2O [mg/l] 0.66 0.41 5.65 3 43 2.55 MgO [mg/l] 1.54 CaO [mg/l] 1.11 BaO [mg/l] 0.41 USP660 (glass grains), Na.sub.2O equiv. [mg/l] — 6.1 4.5 48.5 3.3 ISO4802-2 (tube), Na.sub.2O equiv. [mg/l] 0.6 — — — — Base level untreated [%] 100% 100% 100% 100% 100% Treatment temperature T.sub.B [° C.] 610 590 630 555 580 T.sub.B—T.sub.g [K] 25 30 45 50 50 Treatment time t.sub.B [min] 360 30 15 30 30 Second measurement Li.sub.2O [mg/l] 2.07 0.27 4.84 0.17 Na.sub.2O [mg/l] 1 0.19 1.45 1.4 6.4 0.47 K.sub.2O [mg/l] 0.66 0.16 4.15 1.36 40.3 1.79 MgO [mg/l] 1.54 CaO [mg/l] 1.11 BaO [mg/l] 0.41 USP660 (glass grains), Na.sub.2O equiv. [mg/l] — 4.7 2.3 43 2 ISO4802-2 (tube), Na.sub.2O equiv. [mg/l] 0.3 — — — — Level after thermal treatment [%]  49%  78%  51%  89%  61%

(3) TABLE-US-00004 TABLE 2 Factor V1 V2 V3 V4 V5 SiO.sub.2 [weight-%] 75.2 73 75.5 60.9 75.5 B.sub.2O.sub.3 [weight-%] 10.4 11 16.1 0.5 16.5 Al.sub.2O.sub.3 [weight-%] 5.5 7 16.5 1.5 Li.sub.2O [weight-%] 0.1 Na.sub.2O [weight-%] 7.2 7 0.5 4 K.sub.2O [weight-%] 1 5.1 1.5 MgO [weight-%] 0.5 CaO [weight-%] 1.5 1 0.9 13.1 0.5 BaO [weight-%] 0.6 8 ZnO [weight-%] ZrO.sub.2 [weight-%] 1 1 F [weight-%] 0.2 Cl [weight-%] 0.2 Sum total [weight-%] 100 100 100 100 100 CTE [10.sup.−6/K] 4.9 5.2 4 4.7 3.9 T.sub.g [° C.] 560 555 535 790 525 Ew [° C.] 785 785 785 1005 775 VA [° C.] 1160 1170 1155 1305 1135 First measurement Li.sub.2O [mg/l] 2.07 2.53 Na.sub.2O [mg/l] 1 0.57 0.45 6.3 0.03 41.5 K.sub.2O [mg/l] 0.66 n.d 7.2 11.9 MgO [mg/l] 1.54 0.56 CaO [mg/l] 1.11 n.d 1.94 1.51 0.65 BaO [mg/l] 0.41 <0.50 n.d USP660 (glass grains), Na.sub.2O equiv. [mg/l] — — 61.3 — 50.9 ISO4802-2 (tube), Na.sub.2O equiv. [mg/l] 0.6 0.5 — 1.7 — Base level untreated [%] 100% 100% 100% 100% 100% Treatment temperature T.sub.B [° C.] 600 580 585 825 555 T.sub.B—T.sub.g [K] 40 25 50 35 30 Treatment time t.sub.B [min] 10 5 30 32 30 Second measurement Li.sub.2O [mg/l] 2.07 2.58 Na.sub.2O [mg/l] 1 0.73 0.7 6.9 0.05 44.6 K.sub.2O [mg/l] 0.66 n.d. 91 12.5 MgO [mg/l] 1.54 0.63 CaO [mg/l] 1.11 n.d. 2.48 1.88 0.58 BaO [mg/l] 0.41 <0.50 n.d USP660 (glass grains), Na.sub.2O equiv. [mg/l] — — 75.1 — 54.4 ISO4802-2 (tube), Na.sub.2O equiv. [mg/l] 0.7 0.7 — 2.13 — Level after thermal treatment [%] 128% 156% 123% 125% 107%

(4) In Table 1, examples (A1 to A5) provided according to the invention are outlined and Table 2 outlines non-inventive comparative examples (V1 to V5). The glass composition is specified for each example. In addition, Tables 1 and 2 include four parameters: coefficient of thermal expansion (CTE), glass transition temperature (T.sub.g), softening point (Ew), as well as processing temperature (VA). “n.d.” in the tables indicates “not determined”.

(5) Aside from unavoidable contaminants, the glass compositions in examples A1 to A5 include no Al.sub.2O.sub.3. Thus, all examples are aluminum-free borosilicate glass. The glasses in comparison examples V1, V2 are also borosilicate glasses, however, they are not aluminum-free. The glass in comparison example V4 is an aluminosilicate glass. This glass has an Al.sub.2O.sub.3 content of 16.5 weight-% and a ZrO.sub.2 content of 1 weight-%. This example shows that the presence of a low amount of ZrO.sub.2 does not result in an improvement of the alkali release following a thermal post-treatment.

(6) Two measurements of the alkali release are obtained for each of the examples in Tables 1 and 2. A first measurement was performed on a reference article without thermal post-treatment; the second measurement was performed on an article that was thermally post-treated according to the method disclosed herein. The measurements were performed either according to USP 660 (glass grains) or ISO 720 (glass grains) or according to ISO 4802, whereby in each instance the Na.sub.2O equivalency is stated. In comparison examples V2 and V4, only the release of selected oxides was determined.

(7) For the calculation of the Na.sub.2O equivalency, factors for the alkali oxides or alkaline earth oxides Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO and BaO are specified in Tables 1 and 2. The factors determine the weighting of the individual components for calculation of the Na.sub.2O equivalency. The factors are determined by the molar ratio between Na.sub.2O and the corresponding oxide (i.e. for K.sub.2O: M(Na.sub.2O)/M(K.sub.2O)=[61.979/(2*39.098+15.999)]=0.658). This factor also arises from DIN ISO 4802-2:2017. When calculating the Na.sub.2O equivalency, each measured value for the six components is multiplied with the associated factor and the thus obtained values are then totaled.

(8) In addition, the treatment time t.sub.B, the treatment temperature T.sub.B, as well as the difference T.sub.B-T.sub.g are specified. The treatment time t.sub.B in examples A1 to A5 is between 15 and 360 minutes. The treatment times t.sub.B in the comparative examples are between 5 and 32 minutes. The difference T.sub.B-T.sub.g was between 25 and 50 K in the examples A1 to A5 as well as in the comparative examples V1 to V5.

(9) Examples A1 to A5 indicate a clear reduction of the alkali release of up to 49% of the reference value of the untreated base glass, as a result of the inventive method. In contrast, the inventive thermal post-treatment in comparative examples V1 to V5 results even in an increase in the alkali release of up to 156% of the reference value. This is associated with the non-content or too small a content of ZrO.sub.2.

(10) The influence of the ZrO.sub.2 content upon the efficiency of the inventive method is visible especially in comparison example V3. The glass in this test is aluminum-free, however the ZrO.sub.2 content is only 1 weight-% and thus outside the inventive range. The measurement of the alkali release shows that, in this comparative example, the alkali release increases through the thermal post-treatment provided according to the invention. The aluminum-free glasses in examples A1 to A5 in Table 1 have a respective ZrO.sub.2 content of between 2 and 12 weight-% and the alkali release drops based on the thermal post-treatment provided according to the invention.

(11) TABLE-US-00005 TABLE 3 Na.sub.2O Level OD WT T.sub.B T.sub.B—T.sub.g t.sub.B in equival. alkali Test row in mm in mm Type in ° C. in K min in mg/l release VR1 a 14.25 0.95 tube — — — 0.59 100% b 14.25 0.95 tube 610 25 360 0.3  50% VR2 a 16 1 tube — — — 0.67 100% b 16 1 tube 590 5 5 0.42  63% c 16 1 tube 590 5 15 0.37  56% d 16 1 tube 590 5 30 0.32  47% e 16 1 tube 590 5 120 0.3  44% f 16 1 tube 590 5 360 0.28  41% VR3 a 16 1 tube — — — 0.61 100% b 16 1 tube 610 25 5 0.41  67% c 16 1 tube 610 25 15 0.38  62% d 16 1 tube 610 25 30 0.3  50% e 16 1 tube 610 25 120 0.31  50% f 16 1 tube 610 25 360 0.31  50% VR4 a 16 1 tube — — — 0.6 100% b 16 1 tube 630 45 5 0.32  53% c 16 1 tube 630 45 15 0.32  53% d 16 1 tube 630 45 30 0.3  49% e 16 1 tube 630 45 120 0.27  45% f 16 1 tube 630 45 360 0.25  41% VR5 a 8.65 0.9 tube — — — 1.29 100% b 8.65 0.9 tube 600 15 45 0.91  71% c 8.65 0.9 tube 650 65 30 0.71  55% VR6 a 16 1 tube — — — 0.63 100% b 16 1 tube 685 100 60 0.25  39% c 16 1 tube 685 100 60 0.29  47% VR7 a 16 1 glass grains — — — 4.54 100% b 16 1 glass grains 630 45 15 2.29  51% c 16 1 glass grains 610 25 60 3.8  84% VR8 a 16 1 2R small — — — 3.08 100% b 16 1 bottles 610 25 360 1.74  57% 2R small bottles VR9 a 8.65 0.9 cartridge 1.02 100% b 8.65 0.9 cartridge 610 25 360 0.48  47% VR10 a 8.65 0.9 cartridge — — — 1.16 100% b 8.65 0.9 cartridge 610 25 360 0.46  40% VR11 a 8.65 0.9 cartridge — — — 1.08 100% b 8.65 0.9 cartridge 610 25 360 0.49  46% VR12 a 8.68. 0.9 cartridge — — — 1.26 100% b 8.65 0.9 cartridge 610 25 360 0.47  37%

(12) Table 3 shows the results of a total of twelve test rows: VR1 to VR12. Between two (a, b) and six (a to f) tests were performed respectively in each row. Originating from one reference article (always test a) tests were conducted at different treatment temperatures T.sub.B and over different treatment times t.sub.B.

(13) A glass having the following composition was used in all tests: 73.2 weight-% SiO.sub.2; 10.1 weight-% B.sub.2O.sub.3; 2.9 weight-% Na.sub.2O; 6.1 weight-% K.sub.2O; 7.4 weight-% ZrO.sub.2; 0.1 weight-% Cl and 0.1 weight-% Al.sub.2O.sub.3. The Al.sub.2O.sub.3 content stems from contaminants in the raw materials which are used in the manufacture of glass. The glass used has a glass transition temperature T.sub.g=585° C. With the exception of test row VR7, all tests were performed according to ISO 4802. Test row VR7 was conducted according to USP 660 (glass grains) in order to examine if the reduction in alkali release is independent of the glass material type (grains, tube or container).

(14) In the test rows according to ISO 4802, tubes with a total of three different tubal geometries were used. The tubes in test row VR1 had an outside diameter OD=14.25 mm and a wall thickness WT=0.95 mm. In test rows VR2 to VR4 and VR6 to VR8 tubes with OD=16 mm and WT=1 mm were used. Tests in rows VR5 and VR9 to VR12 were performed with tubes with OD=8.65 mm and WT=0.9 mm. All test rows show the efficiency of the inventive method. The method provided according to the invention can therefore be applied independent of the tubular geometry.

(15) The same applies to the type of glass article, since tests cited in the rows in Table 3 were performed on tubes and different containers and since—as previously stated—a reduction in the alkali release occurred in all test rows based on the method provided according to the invention. On the basis of test rows VR2 to VR4, it can be observed that the alkali release decreases with increasing treatment duration t.sub.B. A comparison between VR2 and VR4 moreover shows that the reduction of the alkali release is greater at a higher treatment temperature T.sub.B but same treatment time t.sub.B. This applies in particular to short treatment times.

(16) The influence of the treatment temperature T.sub.B in the inventive method is recognized also in test rows VR5 and VR7. Tests VR5c and VR7b compared to tests VR5b and VR7c achieve a lower level of alkali release in spite of a shorter treatment time t.sub.B. The reason for this is the treatment temperature T.sub.B which is higher during tests VR5c and VR7b than during tests VR5b or VR7c. It must be noted here, that for tests VR7b and VR7c, initially an untreated glass tube was converted to glass grains according to USP 660 and was then subjected to the inventive thermal post-treatment and that the Na.sub.2O equivalency was determined according to USP 660 or ISO 720 respectively.

(17) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.