Slow cure rate

The choice of coagulant for breaking of the emulsion at the start of the finishing process is dependent on many factors. Salts such as calcium chloride, aluminum sulfate, and sodium chloride are often used. Frequentiy, pH and temperature must be controlled to ensure efficient coagulation. The objectives are to leave no uncoagulated latex, to produce a cmmb that can easily be dewatered, to avoid fines that could be lost, and to control the residual materials left in the product so that damage to properties is kept at a minimum. For example, if a significant amount of a hydrophilic emulsifier residue is left in the polymer, water resistance of final product suffers, and if the residue left is acidic in nature, it usually contributes to slow cure rate. 

Low-pressure mercury lamps consist most frequently of a quartz cylinder with electrodes on both ends, although other shapes are also produced. Inside the lamp is a mixture of mercury and argon at a pressure of 10 to 10 Torn The emission from this lamp is 254 nm, and with high-quality quartz, some light with 189 nm wavelength is produced. Low-pressure lamps are of low power, and therefore are not used for the cure of coatings, but are well suitable for applications where slow cure rate is tolerated, such as liquid crystal displays or in resist technology for the production of microchips. 

Urethane Smell, slow cure rate, not popular... 

More recently, the monofunctional cyanopentadienoates (2) were shown to improve the heat resistance of cyanoacrylate adhesives. In one case, when more than 50 weight % of 2 was combined with a standard cyanoacrylate monomer, the impact, peel, heat, and water resistance were greatly improved. " The improved heat resistance was attributed to the crosslinking of the residual olefin (28) after the anionic polymerization of 2 (see Eq. 8). The cyanopentadienoate was used in 50-90% concentration. The slow cure rate of the dienoate was overcome by the addition of an accelerator, in this case, a small quantity of an alcohol. Improvements in the heat, water, and water vapor resistance of alkyl cyanoacrylates can also... 

Polysulfide pol5uners resistance to moisture vapor transmission is a positive characteristic for applications like insulating glass sealants, but it is a drawback for one-part moisture curing sealants because it leads to relatively slow cure rates. Toray Thiokol has developed new faster curing one-part compositions based on polysulfides with silylthio end groups (4). 

Resins Dienes Primarily butyl-based set resistance Heat resistance Slow cure rate... 

DCBS is a commonly used sulfenamide accelerator that is selected when good scorch safety is needed combined with a relatively slow cure rate. The selection of DCBS is particularly useful when a slow cure rate is needed to optimize rubber adhesion to brass-plated steel tire cord. 

Many times DCBS is selected as the primary accelerator when a slow cure rate is needed to match the slower adhesion chemistry of rubber-to-brass adhesion for steel tire cords. Other commonly used sulfenamide accelerators cure faster than DCBS. 

Other sulfenamide accelerators, such as MBS, can impart a slow cure rate, but not as slow as DCBS. Also, if a primary accelerator is being used with a secondary accelerator (a kicker ), and if the kicker is reduced in loading level, the compound s cure rate may be reduced as well. 

The use of SANTOCURE TBSI primary amine-based accelerator in a NR/SBR 70/30 tyre compound requiring long scorch safety combined with a moderately slow cure rate was studied. The properties of the vulcanisates examined included cure and processing characteristics, physical properties after overcure and ageing, tear strength, compression set, heat build-up and crosslink density distribution. Attempts were made to correlate these properties with the network stmcture. 11 refs. 

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