TYPE RD3-74

Type RD3-74 is a modification of Type F-65 containing a plasticizer. Because most optical cements contract upon curing, they can occasionally set up stresses in thin elements. This stress could either cause bond breakage or lens distortion. Type RD3-74 solves this problem by remaining slightly elastic after curing. 

12300

Lens Bond Type RD3-74,
bottle w/catalyst

4oz

13000

Additional Catalyst

  3cc

13003

Thinner (Monomeric styrene)

4oz

13004

Plasticizer Modifications

.5-5%

 

Approximate Curing Times

  Room Temperature
22°(72°F)
Oven Temperature
70°(160°F)
Catalyst Ratio Pre-Cure Full-Cure Pre-Cure Full-Cure
1:100 2 hours 36 hours Not Recommended
3:100 45 min. 30 hours Not Recommended
5:100 30 min. 1 day Not Recommended
Although we do not recommend complete oven curing, elements that have been pre-cured at room temperature for 30 minutes can then be placed in the oven to achieve full-cure in 1/2 hour.

NOTE: Sufficient catalyst is supplied with each bottle of cement. The catalyst ratio shown at the top is recommended as standard. Changes in the ratio shown will alter the curing times shown, i.e., cure rate can be accelerated slightly by increasing the catalyst.

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 RD3-74 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. (NOTE: Only the amount of cement that can be used within pre-cure time should be prepared.) 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 2:100 mixture, use 2 drops per 3ml. of cement. For 5:100 mixture, use 5 drops per 3ml of cement. (or 8 to 5ml or 40 to 25ml).

N.B. The catalyst bottle supplied with Type RD3-74 Cement contains more than sufficient catalyst for a 5:100 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 RD3-74: 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-cure, 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 no reason to remove holding devices after pre-cure, components should be cured for the total time (pre-cure plus full-cure). 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, mixing procedure, and temperature 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) 
Dispersion Formula...............n=1.5754-(0.04742)-[0.0070/(2-0.028)]+
[0.0011/(2-0.028)2] 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 RD3-74 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 summer optical.