Benzoyl Peroxide
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While in chemical bleaching the impurities are oxidized or reduced to colorless products, optical brighteners that are used in physical bleaching involve introduction of a complementary colour whereby the undesired colour is made invisible to the eye in an optical manner.
Optical brighteners absorb the invisible uv portion of the daylight spectrum and convert this energy into fluorescent blue to blue-violet light. This phenomenon is used to compensates for the absobtion of the short-wavelength light by the textile fibers, which results in yellow cast to fabrics. The end result is attaining a neutral, or even complete white appearance.
Through the use of excess optical brightener more uv radiation can be converted into visible light so that the whiteness is made more sparkling. Since the fluorescent light of a optical brightener is blue-to-violet, excessive use gives either a blue-to-violet or a bluish green cast. |
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CatOnium phase transfer catalysts
( 3 items )
Benzoyl Peroxide
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CatOnium quaternary
ammonium salts are cationic surfactants with extensive use in fabric
softening, hair care formulations, disinfectants, organoclays, and as phase
transfer catalysts.
Three household
product types are manufactured by the use of CatOnium quaternary
ammonium salts: rinse cycle softeners; tumbler dryer sheets; and
detergent containing softeners. Typical rinse cycle softeners contain
3-8% CatOnium salts. When used in tumble dryer sheets, the major role
of CatOnium salts next to the softening effect is to prevent static
charge build up on the clothes during drying and wear. CatOnium salts
are also incorporated in detergents when they are mixed with the other
ingredients. The major benefits of such detergents are fabric
softening, ease of ironing and prevention of build up of static charge
on the clothes.
CatOnium salts are
also used as active ingredients in hare care formulations such as creme
rinses and shampoo conditioners. They provide reduction of combing
forces, increased hair luster, and improved antistatic properties.
Sanitation products
are widely formulated by using CatOnium quaternary ammonium salts.
Compared to other sanitizing chemicals such as phenols, organohalides
and organomercurials, CatOnium salts are less irritating, have very low
odor, and retain long activity. Disinfectants and sanitizers containing
CatOnium salts are used in food and diary industry for sanitization of
the processing equipment, hospitals, public buildings, cooling water
applications, restaurants, food shops etc.
Modification of
clays with CatOnium salts where the adsorbed cation is displaced by the
quaternary ammonium salts results organo-modified clay that can be wet
by organic liquids. Organoclays of this types are used as viscosity
modifiers of nonaqueous liquids such as drilling fluids, greases,
lubricants, and oil-based paints and coatings.
CatOnium quaternary
ammonium and phosphonium salts are widely used as phase
transfer catalysts. Phase transfer catalysis is a phenomenon
of rate enhancement of a reaction between reactants located in
different phases (immiscible liquids or solid and liquid) where the
catalyst extracts one of the reactants, most commonly an anion, across
the interface into the other phase so that reaction can proceed.
Click here to download our
complete delivery program of CatOnium Phase Transfer
Catalysts. |
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Iniper initiators & organic peroxides
( 7 items )
Benzoyl Peroxide
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Iniper organic
peroxides possess one or more oxygen–oxygen bonds, which
decompose thermally to produce two radicals. The rates of
decompositions can be enhanced by specific promoters or activators
being mostly multivalent metals such as iron, cobalt or vanadium. They
significantly decrease the energy necessary to break the
oxygen–oxygen bond. Such accelerated decompositions occur
below the normal application temperatures of the peroxides usually
resulting in generation of only one useful radical, instead of two.
Iniper
Azo-initiators are symmetrical azonitrile compounds decomposing
thermally by cleavage of the two carbon–nitrogen bonds to
form two alkyl radicals and a nitrogen molecule. The resulting
tert-alkyl radicals are generally more stable than most of the radicals
generated from peroxide initiators. In addition, these radicals do not
abstract hydrogens from the polymer backbones, which results in
formation of linear polymers since the branched grafting is suppressed.
Azonitrile
decomposition rates show minor solvent effects and are not affected by
transition metals, acids, bases, and many other components of the
environment. These results in two advantages of azo-initiators; their
decomposition rates predictable and they cane be used for curing resins
that contain a variety of extraneous materials. A drawback of
azonitriles over peroxides, however, is the formation of toxic
tetrasubstituted succinonitrile derivatives due to recombination of the
alkyl radicals. |
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ViaCat tin catalysts
( 4 items )
Benzoyl Peroxide
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Dibutyltin and
monobutyltin compounds are used as esterification
catalysts for the manufacture of organic esters and/or
polyesters. Examples of simple organic esters include plasticizers,
lubricants, and heat-transfer fluids. Polyesters produced by the use of
organotin compounds are used as binders for formulating coatings for
industrial use, or when modified with fatty acids they are used as
binders for air drying coatings for decorative and protective
applications. Dibutyltin compounds are also used as catalysts for
transesterification and polycondensation of dimethyl terephthalate into
polyethylene terephthalate or manufacturing of high molecular weight
copolyester elastomers. The use of these materials is either in
packaging applications or engineering plastics.
The esterification
reactions catalyzed by organotin compounds require temperatures above
200°C, which is much higher than those involving strong acid
catalysts, such as p-toluenesulfonic acid. Though, number of advantages
justifies the use of organotin catalysts. The side reactions are
minimized so the end products have better color and odor properties
because fewer by-products are formed, there is no need for refining to
remove the catalyst residues and the equipment corrosion is eliminated.
Usual levels of tin catalysts are 0.05–0.3 wt % based on the
total reactants charged. |
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Vicura curing agents
( 8 items )
Benzoyl Peroxide
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Vicura crosslinkers alone or in combination with ViaCat catalysts are used as curing agents for both liquid and powder coatings. Resins suitable to be combined with Vicura crosslinkers contain carboxyl, hydroxyl or epoxy groups.
With right resin choice and corresponding Vicura crosslinker coatings with desired storage stability, pot-life, curing temperature, curing speed, flow behavior, mechanical properties, chemical resistance and wheatherability can be formulated.
Products in which Vicura and ViaCat crosslinkers and catalysts are used include polyester powder coatings for indoor and outdoor application, functional epoxy powder coatings, 2 component acrylic coatings for car repair and liquid epoxy coatings for corrosion protection. |
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