Foamed cream time

For the reaction of TDI with a polyether triol, bismuth or lead compounds can also be used. However, tin catalysts are preferred mainly because of their slight odor and the low amounts required to achieve high reaction rates. Carboxylic acid salts of calcium, cobalt, lead, manganese, zinc, and zirconium are employed as cocatalysts with tertiary amines, tin compounds, and tin—amine combinations. Carboxylic acid salts reduce cure time of rigid foam products. Organic mercury compounds are used in cast elastomers and in RIM systems to extend cream time, ie, the time between mixing of all ingredients and the onset of creamy appearance. 

The technical terms employed in the figures are as follows Cream Time—the time between the start of the mixing and the point at which the clear mixture turns creamy or cloudy and starts to expand Gel Time—the time interval between the start of mixing and the start of gelation Rise Time—the time interval between the start of mixing and the completion of expansion of the foaming mass and Tack-Free Time— the time interval between the start of mixing and the time to reach a non-sticky state. 

In the case of conventional urethane-foam processing, cream times are adjusted in the range of about 10 to 30 seconds, and rise times are adjusted in the range of about 60 to 120 seconds. 

Reactivity, seconds Cream time Rise time Tack-free time Foam Properties... 

The NCO/OH equivalent ratio was 5.0 and the aliphaticity index was 0.15. The resultant foam had a cream time of 15 sec, rise time of 20 sec, foam density of 0.041 g/ml, tensile strength in the direction of foam rise of 2.0 kg/cm and a closed-cell content of 90%. 

Examples of the matrix resins employed for SRIM include rigid polyurethane (7,15, 16), or urethane-modified isocyanurate foam (9, 26, 35, 36). The matrix resins for foamed composites are required to have low viscosity and relatively slow cream time for better impregnation into fiber mat and fast-cure cycle time for higher j oductivity. 

CT Cream Time—the time required for the foamable mixture to become creamy after the reaction is started Gel Time—the time required for the inside of the mixture to become hard during foaming, whUe the outer surface begins to have spinability... 

Spermicides, most of which contain nonoxynol-9, are chemical surfactants that destroy sperm cell walls and offer some protection against STDs and cervical cancer. They are available as foams, creams, suppositories, jellies, and flhn. Spermicidal tablets or suppositories require 10 to 30 minutes to dissolve. Spermicides can cause local irritation in both men and women. Additional spermicide must be used each time intercourse is repeated. 

Technological parameters used to characterize the foaming process are cream time, rise time and gel time. Cream time may vary between 0.001 s and 30 s, and rise time is... 

The reaction to form polyurethane foams goes through a number of clearly defined and measurable stages. These stages are Cream time, I/2 Cup time, Full Cup time. String time. Tack Free time and End of Rise time. The effect of various loadings of PFA upon the reactivity of the polyurethane system was measured. These were compared to the reaction times for the standard polyurethane system. The results are given in table 3 and table 4 for undried PFA and dried PFA respectively. 

For the preparation of the foam, a solution of 1 g technical sodium diisobutyl naphthalene sulfonate in 50 ml of 3% orthophosphoric acid is prepared. 20 ml of this solution are poured into a 11 beaker and air is stirred in with a fast running mixer until the cream-like dispersion has reached a volume of 300-400 ml.Then,20 ml of the prepared urea/formaldehyde resin are mixed in, whereby the resin must be evenly distributed. After 3-4 min the introduced resin gellifies into a molded article permeated with many water/air pores under the influence of the acidic catalyst. After 24 h,the crosslinking is completed. Drying for 12 h at 40 °C in a circulating air dryer yields a brittle thermoset foam.The foamed plastic obtained is hydrophobic and has a large internal surface. It can take up about 30 times its own weight of petroleum ether. 

Acne Topical Apply cream, foam, gel, liquid, pads, patch, or soap 1-3 times/day. Callus, corn, wart removal Topical Apply gel, liquid, plaster, or patch to wart 1-2... 

---