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CR – 39 LENSES
MADE BY: SWATI PANARA
FROM : BHARTIMAIYA COLLEGE OF
OPTOMETRY
2nd YEAR 4th SEMESTER
1
CR - 39
• It is also called as Columbia resin or
allyl diglycol carbonate.
• CR – 39 or allyl diglycol carbonate is
a plas...
• CR stands for Columbia Resin & it
is 39th formula of a thermosetting
plastic developed by the Columbia
resin project of ...
• COLUMBIA RESIN batch no. 39
• Petroleum derivative from polyester
group
• Chemically diallyglycol carbonate
• Refractive...
• For years CR- 39 was used without
anti scratch coating.
• Now, however, most CR-39 lenses
come with an anti scratch coat...
• CR-39 plastic lenses do not fog up
as easily as glass lenses.
• Whereas welding or grinding spatter
will pit or permanen...
7
• The material is highly impact
resistant and carries high
transparency.
• Multiple tinting and coating is
possible.
• onl...
ADVANTAGES
• High impact resistance
• Light in weight
• Resistance to chemicals and solvents
• Resistance to heat & temper...
characteristics
• Lightness
• Impact resistance
• Chemical inertness
• Resistance to pitting
• Resistance to fogging
• Tin...
DISADVANTAGES
• Low scratch resistance i.e.
scratches are easily formed
• Increase thickness
• Index variability with temp...
• Can yellow with age
• Softer material surface – scratches
more easily
• Lower refractive index and
variability with temp...
•THANK
YOU
13
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Cr – 39 lenses

  1. 1. CR – 39 LENSES MADE BY: SWATI PANARA FROM : BHARTIMAIYA COLLEGE OF OPTOMETRY 2nd YEAR 4th SEMESTER 1
  2. 2. CR - 39 • It is also called as Columbia resin or allyl diglycol carbonate. • CR – 39 or allyl diglycol carbonate is a plastic polymer commonly used in manufacture of eyeglass lenses. • It was developed by Pittsburgh Plate Glass industries. • It is the thermosetting material. 2
  3. 3. • CR stands for Columbia Resin & it is 39th formula of a thermosetting plastic developed by the Columbia resin project of PPG industries back in 1940. • “CR” stands for Columbia Resin, and the number 39 denotes the type of Columbia Resin used. 3
  4. 4. • COLUMBIA RESIN batch no. 39 • Petroleum derivative from polyester group • Chemically diallyglycol carbonate • Refractive index = 1.498 • Specific Gravity = 1.32 • Abbe value = 58 • Transparency = 92.2 % • UV cutoff = 355 nm 4
  5. 5. • For years CR- 39 was used without anti scratch coating. • Now, however, most CR-39 lenses come with an anti scratch coating, making the material much more scratch resistant. • For smaller, high velocity, sharply pointed objects, CR-39 lenses perform better than chemically tempered glass. 5
  6. 6. • CR-39 plastic lenses do not fog up as easily as glass lenses. • Whereas welding or grinding spatter will pit or permanently stick to glass lenses, it does not adhere to plastic lens material. 6
  7. 7. 7
  8. 8. • The material is highly impact resistant and carries high transparency. • Multiple tinting and coating is possible. • only drawback is weak resistant to abrasion. 8
  9. 9. ADVANTAGES • High impact resistance • Light in weight • Resistance to chemicals and solvents • Resistance to heat & temperature fluctuations • Available in photo chromic glasses • U.V. protection • Can be tinted & coated • Inexpensive 9
  10. 10. characteristics • Lightness • Impact resistance • Chemical inertness • Resistance to pitting • Resistance to fogging • Tint ability • Versatility in optical design 10
  11. 11. DISADVANTAGES • Low scratch resistance i.e. scratches are easily formed • Increase thickness • Index variability with temperature • Inferior photo chromic properties • Surface abrasion • Warp age upon glazing 11
  12. 12. • Can yellow with age • Softer material surface – scratches more easily • Lower refractive index and variability with temp. 12
  13. 13. •THANK YOU 13
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