Abstract This invention is directed to the production of essentially lead-free glass compositions demonstrating softening points below 500° C. and coefficients of thermal expansion somewhat below 88×10 -7 /°C. The glasses consist essentially, in weight percent on the oxide basis, of ______________________________________ Li 2 O
1-4 Na 2 O + K 2 O
0-12
ZnO 20-30 CaO 0-7
B 2 O 3 32-42 SrO 0-10
Al 2 O 3 2-5 BaO 0-15
ZrO 2 2-6 CaO + SrO + BaO
0-15
P 2 O 5 6-10 V 2 O 5 0-22
Na 2 O
0-8 Bi 2 O 3 0-16
K 2 O
0-8.40 V 2 O 5 + Bi 2 O 3 5-25
______________________________________ wherein a minimum of 5% V 2 O 5 +Bi 2 O 3 is required in the presence of a least 2% Na 2 O or 5% K 2 O, and a minimum of 9% V 2 O 5 +Bi 2 O 3 is required in the essential absence of Na 2 O or K 2 O, but in the presence of at least 3% CaO or 6% SrO or 9% BaO.
An essentially lead-free glass composition consisting essentially, expressed in terms of weight percent on the oxide basis, of ______________________________________
Li.sub.2 O
1-4 Na.sub.2 O + K.sub.2 O
0-12
ZnO 20-30 CaO 0-7
B.sub.2 O.sub.3
32-42 SrO 0-10
Al.sub.2 O.sub.3
2-5 BaO 0-15
ZrO.sub.2
2-6 CaO + SrO + BaO
0-15
P.sub.2 O.sub.5
6-10 V.sub.2 O.sub.5
0-22
Na.sub.2 O
0-8 Bi.sub.2 O.sub.3
0-16
K.sub.2 O
0-8.40 V.sub.2 O.sub.5 + Bi.sub.2 O.sub.3
5-25
______________________________________ wherein a minimum of 5% V 2 O 5 +Bi 2 O 3 is required in the presence of at least 2% Na 2 O or 5% K 2 O, and a minimum of 9% V 2 O 5 and/or Bi 2 O 3 is required in the essential absence of Na 2 O or K 2 O, but in the presence of at least 3% CaO or 6% SrO or 9% BaO, said glass exhibiting a softening point below 500° C., a maturing temperature no higher than 560° C., and a coefficient of thermal expansion (0°-300° C.) below about 88×10 -7 /°C. but not less than about 80×10 -7 /°C.
Claim 2
Dependent Claim
183 words
An essentially lead-free glass composition consisting essentially, expressed in terms of weight percent on the oxide basis, of ______________________________________
Li.sub.2 O
1-4 Na.sub.2 O + K.sub.2 O
0-12
ZnO 20-30 CaO 0-7
B.sub.2 O.sub.3
32-42 SrO 0-10
Al.sub.2 O.sub.3
2-5 BaO 0-15
ZrO.sub.2
2-6 CaO + SrO + BaO
0-15
P.sub.2 O.sub.5
6-10 V.sub.2 O.sub.5
0-22
Na.sub.2 O
0-8 Bi.sub.2 O.sub.3
0-16
K.sub.2 O
0-8.40 V.sub.2 O.sub.5 + Bi.sub.2 O.sub.3
5-25
______________________________________ wherein a minimum of 5% V 2 O 5 +Bi 2 O 3 is required in the presence of at least 2% Na 2 O or 5% K 2 O, and a minimum of 9% V 2 O 5 and/or Bi 2 O 3 is required in the essential absence of Na 2 O or K 2 O, but in the presence of at least 3% CaO or 6% SrO or 9% BaO, said glass exhibiting a softening point below 500° C., a maturing temperature no higher than 560° C., and a coefficient of thermal expansion (0°-300° C.) below about 88×10 -7 /°C. but not less than about 80×10 -7 /°C.
Claim 3
Dependent Claim
25 words
A glass according to claim 1 wherein said V 2 O 5 and/or Bi 2 O 3 is present in an amount of about 10-15%.
Claim 4
Dependent Claim
35 words
A glass according to claim 1 having the following approximate composition: ______________________________________
Li.sub.2 O
2.47 ZrO.sub.2
3.86
ZnO 23.58 P.sub.2 O.sub.5
7.83
B.sub.2 O.sub.3
36.56 K.sub.2 O
8.15
Al.sub.2 O.sub.3
3.64 Bi.sub.2 O.sub.3
13.4.
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