.jpg)
.jpg)
FAQs: LORD Electronic Materials
ELECTRONIC POTTINGS, COATINGS AND ENCAPSULANTS
- Check to make sure the appropriate mix ratio was used.
(By weight or by volume). - Was the material mixed thoroughly?
(Was the filler re-suspended if settled?) - Check cure times and temperature.
(See Technical Data Sheet for recommended cure times and temperature.) - The cure rate of material will vary depending upon mass. Room temperature cure materials will cure faster in larger masses while smaller amounts of material may take much longer to cure.
- Proper curing conditions for silicones.
- Condensation cured silicones need an open or near open mold to cure properly.
- Cured silicone may be inhibited by surface contaminates such as —
Sulfur compounds: Thiols, Sulfides, Sulfates, Sulfites and Thiourea - Rubbers with vulcanized sulfur —
Nitrogen compounds: Amines, Amids, Imides and Azides - Plastics cured with amines
- Materials containing organic acids
- Tin compounds
- RTV silicone rubbers catalyzed with metal salts
- Has the shelf life of the material expired?
(If the shelf life of the material has expired, we recommend that you do not use the material or contact LORD for re-certification.) Most silicones and urethanes have a six month shelf life and epoxies have normally one year (except single components). - Was the material stored properly?
(Follow recommended storage conditions according to Technical Data Sheets.)
- Abrasion or acid etching of the surface is advisable in some instances.
- Clean the substrate surface (Acetone, IPA, Xylene).
- Elevated temperature cured systems – An increase in temperature will speed up the gel and handling time of the material. ***Speeding up the cure may cause stress on parts not normally seen with lower temperature cure rates and it will also shorten your working time.
- Condensation cured materials (silicones) can be heated to a max temperature of 60°C until cure takes place.
- If isocyanate is crystallized, it is recommended to warm the material between 50°C and 55°C.
- Prolonger exposure to temperature below 15°C will cause crystallization.
- Metal, glass, and polyethylene straight-sided receptacles are recommended for mixing.
- Stirring should be done with metal spatulas with squared-off ends. Do not use wooden sticks or paper tubs for mixing. "Poly" lined cups and tubs are acceptable for single-shot use.
A. In many cases, it is desirable to de-air the material after mixing. The receptacle is placed in a chamber and subjected to a vacuum of 2 millimeters of mercury (29.8˝ hg) for approximately three to five minutes. The vacuum should be held for a minute or two after the collapse of the foam head while minor bubbling continues and then slowly released.
A. Some materials will need to be blanketed with nitrogen or argon to ensure that moisture doesn’t contaminate the material. (Anhydrides, Urethane Resins and Isocyanates are some of the common materials that need to be nitrogen layered.)
A. If a material has separated in the container, the material will need to be re-dispersed before using. Using the material in a settled state may cause issues with cure rates and may inhibit cure completely. Most materials can be remixed by simply using a metal spatula to agitate the material until uniform. If the material is heavily filled, then a paint shaker or mixing blade with a drill or drill press may be needed to properly re-mix filler into the system.
A. Epoxy resin-hardener ratios are proportioned by weight. In most cases, these ratios are stoichiometric and must be strictly adhered to. For high rates of production, automated meter-mix equipment is a necessity. Small batches are weighed out on a balance scale in a clean container with ample room for mixing. Hardness may vary if the recommended mix ratio is not used.
Silicones and urethanes – mix ratio accuracy is necessary to ± 2% to ensure proper cure and de-mold times. Hardness may vary if the recommended mix ratio is not used.
A. Durometer hardness is used to determine the relative hardness of soft materials, usually plastic or rubber. The test measures the penetration of a specified indentor into the material under specified conditions of force and time. The hardness value is often used to identify or specify a particular hardness of elastomers or as a quality control measure on lots of material.
To meet a request for a state-of-the-art thermal interface material that would dissipate heat from high-powered com...
LORD Corporation has sold its cermet thick film business to Heraeus Materials Technology LLC for an undisclosed amo...