US5281560A — Non-lead sealing glasses

Claim 1

Independent Claim 118 words

A lead-free, tin phosphate glass, the composition of which, as calculated in mole percent on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one stabilizing oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SO 2 , and up to 5% WO 3 .

Claim 2

Dependent Claim 118 words

A lead-free, tin phosphate glass, the composition of which, as calculated in mole percent on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one stabilizing oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SO 2 , and up to 5% WO 3 .

Claim 3

Dependent Claim 27 words

A phosphate glass in accordance with claim 1 wherein the selected stabilizing oxide is at least B 2 O 3 and one of Al 2 O 3

Claim 4

Dependent Claim 19 words

A phosphate glass in accordance with claim 1 wherein the P 2 O 5 content is 29-35 mole percent.

Claim 5

Dependent Claim 19 words

A phosphate glass in accordance with claim 3 wherein P 2 O 5 content is about 33 mole percent.

Claim 6

Dependent Claim 55 words

A phosphate glass in accordance with claim 1 which also contains an effective amount of at least one seal adherence promoter in the indicated proportion selected from the group consisting of up to 5 mole % WO 3 , up to 5 mole % MoO 3 , and up to 0.10 mole % Ag metal.

Claim 7

Dependent Claim 127 words

A sealing material containing as an active ingredient a lead-free, tin phosphate glass frit, the composition of which, as calculated in mole percent, on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one stabilizing oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SiO 2 , and up to 5% WO 3 .

Claim 8

Dependent Claim 127 words

A sealing material containing as an active ingredient a lead-free, tin phosphate glass frit, the composition of which, as calculated in mole percent, on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one stabilizing oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SiO 2 , and up to 5% WO 3 .

Claim 9

Dependent Claim 26 words

A sealing material in accordance with claim 6 wherein the selected stabilizing oxide is at least B 2 O 3 and/or Al 2 O 3 .

Claim 10

Dependent Claim 58 words

A sealing material in accordance with claim 6 wherein the phosphate glass additionally contains an effective amount of at least one seal adherence promoter in the indicated proportion selected from the group consisting of up to 5 mole % WO 3 , up to 5 mole % MoO 3 , and up to 0.10 mole % Ag metal.

Claim 11

Dependent Claim 35 words

A sealing material in accordance with claim 6 additionally containing a mill addition having a low coefficient of thermal expansion to reduce the effective coefficient of thermal expansion of the frit in a fusion seal.

Claim 12

Dependent Claim 43 words

A sealing material in accordance with claim 9 wherein the mill addition is selected from the group consisting of lithium aluminosilicate glass-ceramics, cordierite, and a pyrophosphate having at least one cation selected from the group consisting of Mg +2 and Co +2 .

Claim 13

Dependent Claim 22 words

A sealing material in accordance with claim 10 wherein the mill addition is composed of particles of a magnesium pyrophosphate crystalline material.

Claim 14

Dependent Claim 23 words

A sealing material in accordance with claim 6 containing a strength reinforcing filler having a coefficient of expansion less than 120×10 -7 /°C.

Claim 15

Dependent Claim 23 words

A sealing material in accordance with claim 12 wherein the strength reinforcing filler is selected from the group composed of alumina and zircon.

Claim 16

Dependent Claim 22 words

A sealing material in accordance with claim 6 wherein the phosphate glass contains about 33 mole percent P 2 O 5 .

Claim 17

Dependent Claim 152 words

A composite article composed of at least two component parts, the parts being joined by a fusion seal that is the fused product of a sealing material containing as an active ingredient a SnO-ZnO-P 2 O 5 sealing glass frit, the composition of which, as calculated in mole percent on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SiO 2 , and up to 5% WO 3 .

Claim 18

Dependent Claim 152 words

A composite article composed of at least two component parts, the parts being joined by a fusion seal that is the fused product of a sealing material containing as an active ingredient a SnO-ZnO-P 2 O 5 sealing glass frit, the composition of which, as calculated in mole percent on an oxide basis, consists essentially of 25-50% P 2 O 5 , 30-70% SnO, 0-15% ZnO, the mole ratio of SnO:ZnO being greater than 5:1, and an effective amount up to 25% total of at least one oxide in the indicated proportion selected from the group consisting of up to 25% R 2 O, wherein R 2 O consists of 0-25% Li 2 O, 0-25% Na 2 O, and 0-25% K 2 O, up to 20% B 2 O 3 , up to 5% Al 2 O 3 , up to 5% SiO 2 , and up to 5% WO 3 .

Claim 19

Dependent Claim 35 words

An article in accordance with claim 15 wherein the sealing material additionally contains a mill addition having a low coefficient of thermal expansion to reduce the effective coefficient of thermal expansion in the fused product.

Claim 20

Dependent Claim 42 words

An article in accordance with claim 16 wherein the mill addition is selected from the group consisting of lithium aluminosilicate glass-ceramics, cordierite, and a pyrophosphate having at least one cation selected from the group consisting of Mg +2 and Co +2 .

Claim 21

Dependent Claim 28 words

An article in accordance with claim 15 wherein the fusion seal additionally contains a strength reinforcing filler having a coefficient of thermal expansion less than 120×10 -7 /°C.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-01-24	1997-07-26	1998-01-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-01-24	2001-07-26	2002-01-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-01-24	2005-07-26	2006-01-25	$7700.00	Window Closed / Lapsed

Non-lead sealing glasses

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