PLANT PARAMETERS
Capacity (Depends on Requirement)	2 ‘ x 2’ polycarbonate sheets
Number of Shifts/day	1
Working days/Year	300
Total Land Area, m²	2000
Covered Area, m²	1000
MANPOWER
Managerial	1
Skilled	2
Unskilled	2
RAW MATERIAL
Alkomide & related chemicals	Inorganic oxide nanoparticles
Imported Chemical
UTILITIES

Power
Water
PLANT & MACHINERY
Dip coating unit	Oven
UV curing machine with conveyor system	Centrifuge
PH meter	Refrigerator
The above figures are for budgetary purposes only and subject to change in subsequent offers

INTRODUCTION

Transparent polycarbonate plastics and other related plastic materials are promising materials for optical applications. Some important properties are: (i) excellent clarity (ii) complete UV cut off (iii) can withstand 250 times greater impact than glass (i.e. virtually unbreakable) etc. Such qualities offer a lot of industrial applications of polycarbonates and presently glasses (including ophthalmic) are being replaced by transparent plastics (e.g. polycarbonates, polyallyl bicarbonate etc.).

One of the main disadvantages of these plastics is that they are not scratch resistant enough; as a result their optical properties are being deteriorated very quickly due to surface damage. In particular, this problem seems to be severe due to dust and smoke pollution. Scratch-resistant coating of these plastics with hard materials seems to be a means to overcome this hurdle. The scratch-resistant film coated plastics can be utilized as substitute of glass windows for domestic, railway compartments and other related applications.

PROCESS

Coated sheet/lenses

Inorganic-organic hybrid coating sols having longer shelf life, suitable for deposition of scratch resistant coatings on polycarbonate (PC) sheets and lenses have been developed. PC lenses and large sized sheets can be coated with these sols by dip-coating technique. Scratch resistant protective coatings with an improvement of surface quality and increase of optical transmission can be obtained after oven drying and UV curing of the above coated PC substrates.

Sol gel stability is approx. 6 months.

ADVANTAGES

Novelty of the present invention lie in obtaining a sol which is stable, can provide better scratch resistant coating on polycarbonate sheets and lenses with an increase of 2-3 % optical transmission.

The resultant coatings 5-8 mm in thickness is optically transparent having refractive index of 1.50-1.52 and showed good abrasion property. The optical transmission of the coated polycarbonate is increased to 2-3 % compared to the uncoated substrate. The cross-cut adhesive test (following DIN 53151 specification) shows no damage of the coatings and can be classified as ASTM 5B (highest standard). The abrasion test of the coating was performed using US federal specification lens coating hardness tester kit in accordance with MIL-E-12397B. The abrasion test was done by rubbing the abrading head (with 2½ lbs of pressure) across the coated and uncoated surfaces of polycarbonate. After rubbing, the surface was examined with the profilometer. It has been observed that the uncoated polycarbonate is suffering from damage even after 1-5 times of abrasion. Whereas 20 abrasion cycles is the specification of this test. On the

contrary, the coated polycarbonate showed resistance towards damage even after more than 100 times of abrasion confirming the coatings are highly abrasion resistant.

SCALE OF DEVELOPMENT

Ophthalmic lenses and sheet 2 ‘ x 2’ and can be demonstrated at 1 ‘ x 1’. .

SALIENT FEATURES

· The coatings developed on polycarbonate are transparent, spot-free and UV-curable; coating hardness – 4H (ASTM-D3363), ISO 15184; coating passed all standard international specifications (adhesion, abrasion, chemical durability etc.).

· The coatings developed at CR 39® are transparent, spot-free and thermally (90 deg. C) curable; coating hardness > 6H; coating passed all standard international specifications (adhesion, abrasion, chemical durability etc.).

PLANT & MACHINERY

INTRODUCTION

PROCESS

Coated sheet/lenses

SCALE OF DEVELOPMENT

SALIENT FEATURES