TYPE DC-90

A Hybrid Two-Component UV Sensitive Cement

Summers Optical has developed a hybrid two component ultraviolet sensitive cement that offers offers optical companies some of the benefits of ultraviolet pre-curing while assuring the complete cures, low strain and excellent thermal and chemical resistance of two component optical cements. 

Lens Bond Type DC-90 permits the user to pre-cure the elements in approximately 12 minutes using a low wattage black light and then full cure at room temperature without any additional UV exposure in 48 to 72 hours. The low viscosity, high flow and wetting abilities of Type DC-90 eliminate the problem of working out entrapped air between large lens and optical filters. The longer room temperature full cure permits a very strong mechanical as well as chemical bond to the substrates while the short pre-cure reduces the need for an excessive number of holding devices.

Pre-Cure and full-cure times are dependent on the UV transmission of the element being bonded.

12301

Lens Bond Type DC-90,
bottle w/catalyst

4oz

13000

Additional Catalyst

  3cc

13003

Thinner (Monomeric styrene)

4oz

13004

Plasticizer Modifications

.5-5%

 

Approximate Curing Times

Pre-Cure Full-Cure
Room Temperature 22°C (72°F) using Longwave radiation approximately 1" above the element. Room temperature using 22°C (72°F) without UV exposure or additional heat.
12 minutes 48 hours
NOTE: Pre-Cure time presupposes at least 70% UV transmission of the elements being bonded. The elements are on a white background and the light source is emitting 15 watts of 365nm light. The elements can be placed in a oven at 70°C after pre-curing for 1 hour for full cure, but for best low stress results, room temperature full curing is suggested. 

For more information on our ultraviolet curing lamps please see our cementing department supply section of our web site.

Instructions For Use

1. Preparation of Elements: Other than normal cleaning procedures, no special preparation is required. The best final cleaner is reagent grade or C.P. acetone.

2. Preparation of Cement: Prepare Type DC-90 by the addition of catalyst to cement in a clear glass container. Thorough mixing is important. While stirring, hold container up to the light and observe the Schlieren Effect. When the Schlieren Effect disappears, continue mixing for at least 30 seconds. The entrapped air in the cement will surface if the mixture rests at room temperature for a short time, or is briefly subjected to a vacuum of 625mm Hg. (25" Hg.) The catalyst bottles have a specially designed controlled-drop tip, pre-calibrated at our laboratory to an accuracy of ± 1%. To use, squeeze the inverted bottle, allowing one drop to fall at a time. For 3:100 mixture, use 3 drops per 3ml. of cement.

N.B. The catalyst bottle supplied with Type DC-90 Cement contains more than sufficient catalyst for a 3:100 catalyst:cement ratio.

Safety: Although LENS BOND is quite safe to use, some persons may be sensitive to the chemicals comprising the formulation. For them, the use of finger cots or gloves is recommended. Adequate ventilation should be provided.

3. Application and Curing of Type DC-90: Place the prepared LENS BOND on the concave surface, and place the convex surface thereon. Press down firmly and gently until LENS BOND completely wets the matching surfaces. Then, with a slow rotary motion and light pressure, force air bubbles from between the lenses. Excess Cement can be removed with a cloth slightly moistened with alcohol or acetone. (Excess solvent will remove cement from between the cemented components.) After pre-curing with an ultraviolet light, holding devices can be removed and the components carefully cleaned. Before environmental testing, however, the lenses must be fully cured.

Full-cure time is in addition to the pre-cure time. If there is any doubt about cure being achieved, allow components to cure for a longer period of time. The Cement will not overcure. If cure is not achieved in a reasonable amount of time, the catalyst ratio, UV transmission of elements, distance of lamp and power of light source should be checked.

Note: If the elements will undergo hostile environmental tests, allow 48 to 72 hours between full-cure and testing.

Specifications

Viscosity........................275 cps. to 320 cps. 
Refractive Index (full-cured)....1.55 at 25°C 
Refractive Index (uncured).......1.53 
Operational Temperature Range....-54°(-65°F) to 100°C(212°F) 
Youngs Modulus...................6.2 x 105lbs/in2 
Shear Strength...................5200 lbs/in2 
Impact...........................(.3 to .4)ft lb/in 
Specific Heat....................(.2 to .4) Cal/gm 
Dielectric Constant..............3 at 106 cps 
Loss Factor at 106 cps...........(.05) 
Water Absorption.................0.3% (24 hours. 25°C on bulk material) 
Shrinkage on Cure................Approximately 4% 
pH...............................3.2 
Specific Gravity.................1.22 
Shore D. Hardness................Approximately 90 
Surface Tension..................44 Dynes/cm.
Linear Coefficient of Expansion..Approximately 6.3x10-5/°C at between 27°C-100°C
                                 5.58x10-5/°C at between 100°C-200°C 
Thermal Conductivity.............500x10-6 cal(sec)(sq.cm)(°C)(cm) 
Flash Point (uncured)............50°C 
Glass Transition (Tg)............>90°C 
Shipping and Storage.............Type DC-90 needs no special handling or
                                 storage. It should, however, be kept 
                                 away from intense light and elevated 
                                 temperatures. 
Shelf Life.......................18 months from date of manufacture 
Size.............................114 gm(4oz)
*For technical data on adhesion properties, solvent and thermal resistance 
as well as transmission studies, please go to our technical data section 
on this site.