Additives silicone formulations

Chemical modification of the wax can improve smear resistance (5). Silicones, which do not harm furniture finishes (6), are incorporated as film-forming ingredients in furniture polishes. The lubricant properties of silicones improve ease of application of the polish and removal of insoluble soil particles. In addition, silicones make dry films easier to buff and more water-repellent, and provide depth of gloss, ie, ability to reflect a coherent image as a result of a high refractive index (7). Wax-free polishes, which have silicones as the only film former, can be formulated to deliver smear resistance (8). Another type of film former commonly used in oil-base furniture polishes is a mineral or vegetable oil, eg, linseed oil. 

Hydrophilic contact lenses (such as Soflens) are made from crosslinked poly(2-hydrox-yethyl methacrylates). These have also been utilised as drug carriers. Conventional eye medication has been modified over the years through the addition to formulations of a variety of viscosity-enhancing agents, polymers such as hydroxypropylmethyl cellulose, poly(vinyl alcohol) and silicones. These all prolong contact of dmg with the cornea by... 

EFFECT OF PLASTICIZERS ON POLYMER AND OTHER ADDITIVES Figure 11.74 shows that silicone mbber responds to plasticization in a similar manner as other polymers. Modulus and elongation increase with the amount of plasticizer increase. The tensile strength is decreased with increased addition of plasticizer. Plasticizer type plays some role but all tested plasticizers have similar compatibility with polymer. Addition of ester type plasticizers to silicone formulation increased UV absorption and UV degradation rate of mbber. ... 

A number of additives are included in metal decorating enamels, the most important of which are slip flow additives (silicone and non-silicone types) and polyolefine wax dispersions. Incorporation of waxes into the formulation aids the forming and tooling operations and promotes mar resistance. 

Silicone Heat-Cured Rubber. Sihcone elastomers are made by vulcanising high molecular weight (>5 x 10 mol wt) linear polydimethylsiloxane polymer, often called gum. Fillers are used in these formulations to increase strength through reinforcement. Extending fillers and various additives, eg, antioxidants, adhesion promoters, and pigments, can be used to obtain certain properties (59,357,364). 

Another important application area for PSAs in the electronic industry focuses on the manufacturing, transport and assembly of electronic components into larger devices, such as computer disk drives. Due to the sensitivity of these components, contamination with adhesive residue, its outgassing products, or residue transferred from any liners used, needs to be avoided. Cleanliness of the whole tape construction becomes very critical, because residuals like metal ions, surfactants, halogens, silicones, and the like can cause product failures of the electronic component or product. Due to their inherent tackiness, acrylic PSAs are very attractive for this type of application. Other PSAs can be used as well, but particular attention has to be given to the choice of tackifier or other additives needed in the PSA formulation. The choice of release liner also becomes very critical because of the concern about silicone transfer to the adhesive, which may eventually contaminate the electronic part. 

Addition cure silicones can be delivered from solvent, waterborne emulsions, or 100% solids systems. The solvent free versions employ base polymers of intermediate molecular weight to achieve processable viscosity. These base polymers can have reactive moieties in terminal and/or pendant positions. These lower molecular weight, more functional systems result in a tighter crosslink network which feels rubbery to the hand. Low amounts of high molecular weight additives are included in some formulations to provide a more slippery feel [51,52]. 

When formulating a silicone adhesive, sealant, or coating, based on hydrosilylation addition cure, one must consider the following properties of the uncured product pot life, dispensing technique, rheology, extrusion rate, cure performance. These characteristics directly affect the processing properties of the polymer base or crosslinker parts. The degree of cure conversion at the temperature of interest is determined by properties such as tack free time, cure profile and cure time. Once... 

Silicones may improve the properties of a Portland cement formulation [1267] when added to the cement in amounts of 0.2% to 2%. An example of a formulation of the additive is given in Table 18-8. 

The coal-water mixture fed to the boilers has to be formulated to a certain specification. This is done with the proper inclusion of additives to facilitate combustion. The recommended additives include a petroleum-based surfactant (polysulfones or polycar-boxylates), a stabilizing (e.g. xanthan gum), a biocide and an anti-foaming agent (such as a silicone base). 

Industrially, silicone surfactants are used in a variety of processes including foam, textile, concrete and thermoplastic production, and applications include use as foam stabilisers, defoamers, emulsifiers, dispersants, wetters, adhesives, lubricants and release agents [1]. The ability of silicone surfactants to also function in organic media creates a unique niche for their use, such as in polyurethane foam manufacture and as additives to paints and oil-based formulations, whilst the ability to lower surface tension in aqueous solutions provides useful superwetting properties. The low biological risk associated with these compounds has also led to their use in cosmetics and personal care products [2]. 

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