US4367919A
Expired / Lapsed
US
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Durable glass elements
Assignee: 3M Co
•
Filing: 1981-03-19
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Granted: 1983-01-11
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Expires: 2001-03-19
Abstract
Abstract Glass microspheres and other glass elements based on B 2 O 3 , BaO, SiO 2 and TiO 2 have an improved combination of crushing strength, index of refraction, and, especially in some formulations, chemical resistance. The microspheres are especially adapted for use as retroreflective elements in pavement markings.
Inventors
- 👤 Chi F. Tung
- 👤 Benjamin T. Fellows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:54
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/12; C03C3/14; C03C12/00; C03C12/02; C03C3/04; C03C3/062; C03C3/064; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/901; Y10S501/903
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
125 words
Durable visibly transparent clear microspheres less than about 2 millimeters in diameter, containing no more than about 5 weight-percent scattered crystallinity, and adapted for use as a reflective element in a pavement marking, said microspheres being formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 5-20
TiO.sub.2 20-40
BaO and/or SrO 10-35
Alkali-metal oxide 0-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO, and containing no more than 10 weight-percent ZnO; and said glass having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 2
Dependent Claim
125 words
Durable visibly transparent clear microspheres less than about 2 millimeters in diameter, containing no more than about 5 weight-percent scattered crystallinity, and adapted for use as a reflective element in a pavement marking, said microspheres being formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 5-20
TiO.sub.2 20-40
BaO and/or SrO 10-35
Alkali-metal oxide 0-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO, and containing no more than 10 weight-percent ZnO; and said glass having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 3
Dependent Claim
13 words
Microspheres of claim 1 which include at least 1 weight-percent of alkali-metal oxide.
Claim 4
Dependent Claim
16 words
Microspheres of claim 1 or 2 which include 0.5 to 5 weight-percent of a metal fluoride.
Claim 5
Dependent Claim
12 words
Microspheres of claim 3 in which the metal fluoride is sodium fluoride.
Claim 6
Dependent Claim
15 words
Microspheres of claim 1 which include at least 10 weight-percent B 2 O 3 .
Claim 7
Dependent Claim
106 words
Durable visibly transparent clear microspheres between about 0.25 and 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 10-20
TiO.sub.2 25-35
BaO and/or SrO 15-25
Alkali-metal oxide 2-10
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-35
NaF 1-3;
______________________________________ said glass being essentially free of CaO and containing no more than 10 weight-percent ZnO, having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 8
Dependent Claim
106 words
Durable visibly transparent clear microspheres between about 0.25 and 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 10-20
TiO.sub.2 25-35
BaO and/or SrO 15-25
Alkali-metal oxide 2-10
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-35
NaF 1-3;
______________________________________ said glass being essentially free of CaO and containing no more than 10 weight-percent ZnO, having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 9
Dependent Claim
23 words
Pavement marking tape comprising a backing and a layer of microspheres of claim 1, 2, 4, 5, or 6 carried on the backing.
Claim 10
Dependent Claim
124 words
Durable visibly transparent clear microspheres less than about 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and adapted for use as a reflective element in a pavement marking, said microspheres being formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 10-20
TiO.sub.2 20-40
BaO and/or SrO 10-35
Alkali-metal oxide 0-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 20-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO, and containing no more than 10 weight-percent ZnO; and said glass having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 11
Dependent Claim
124 words
Durable visibly transparent clear microspheres less than about 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and adapted for use as a reflective element in a pavement marking, said microspheres being formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 10-20
TiO.sub.2 20-40
BaO and/or SrO 10-35
Alkali-metal oxide 0-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 20-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO, and containing no more than 10 weight-percent ZnO; and said glass having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 12
Dependent Claim
13 words
Microspheres of claim 8 which include at least 1 weight-percent of alkali-metal oxide.
Claim 13
Dependent Claim
13 words
Microspheres of claim 8 which include at least 1 weight-percent K 2 O.
Claim 14
Dependent Claim
17 words
Microspheres of claim 8, 9, or 10 which include 0.5 to 5 weight-percent of a metal fluoride.
Claim 15
Dependent Claim
108 words
Durable visibly transparent clear microspheres between about 0.25 and 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 5-20
TiO.sub.2 25-50
BaO and/or SrO 15-25
Alkali-metal oxide 2-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO and containing no more than 10 weight-percent ZnO, having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 16
Dependent Claim
108 words
Durable visibly transparent clear microspheres between about 0.25 and 2 millimeters in diameter, containing no more than 5 weight-percent scattered crystallinity, and formed from glass that consists essentially of ingredients as listed in the following table, in which percentages are given by weight: ______________________________________
B.sub.2 O.sub.3 5-20
TiO.sub.2 25-50
BaO and/or SrO 15-25
Alkali-metal oxide 2-15
selected from Na.sub.2 O and K.sub.2 O
SiO.sub.2 25-40
All other ingredients
0-15;
______________________________________ said glass being essentially free of CaO and containing no more than 10 weight-percent ZnO, having an index of refraction between 1.6 and 1.9, and exhibiting a crush resistance of at least about 3500 kilograms per square centimeter.
Claim 17
Dependent Claim
14 words
Microspheres of claim 12 which include at least 1 weight-percent of K 2 O.
Claim 18
Dependent Claim
16 words
Microspheres of claims 12 or 13 which include 0.5 to 5 weight-percent of a metal fluoride.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |