Pastel shades

Since acetal resins are degraded by ultra violet light, additives may be included to improve the resistance of the polymer. Carbon black is effective but as in the case of polyethylene it must be well dispersed in the polymer. The finer the particle size the better the ultra violet stability of the polymer but the poorer the heat stability. About 1.5% is generally recommended. For white compounds and those with pastel colours titanium dioxide is as good in polyacetals as most transparent ultraviolet absorbers, such as the benzophenone derivatives and other materials discussed in Chapter 7. Such ultraviolet absorbers may be used for compounds that are neither black, white nor pastel shade in colour. 

Fein-erz, n. fine ore. -farbe,/. (Dyeing) pastel shade. 

The key properties here are hardness and wear resistance, ability to. stand minor knocks and dents without cracking and resistance to various domestic chemicals. These vary with type of appliance, e.g. detergent solutions are important for washing machines, while a fridge will be required to withstand fruit juices, ketchup and polishes. Good colour and appearance in white and mainly pastel shades will be expected. Corrosion resistance is required, especially for washing machines, and domestic appliances frequently have to withstand humid conditions in kitchens. 

P.Y.97 is used in a variety of fields. Even in pastel shades, it is used in industrial finishes while its full shades lend color to automobile refinishes. In emulsion paints, both its medium and full shades are suited to exterior application. The printing ink industry uses P.Y.97 in high grade printing products, especially where excellent fastness is required, such as in stable posters, etc. It lends itself without difficulty to all printing techniques. However, lack of fastness to monostyrene and acetone and therefore a certain tendency to bleed in these media precludes its application in deco printing inks, i.e., for decorative laminates. 

Flowers of perennial iberis tend to be white this is an annual mix of pastel shades grown as summer bedding. 

Because of increasing standards of wetfastness, lightfast reactive dyes are also being used in polyamide printing, especially to produce pastel shades, (see Section 3.1). 

Prebleached wool becomes somewhat yellow on dyeing. To obtain clear pastel shades bleach and dye are used preferably in the same bath. Mildly bleaching reducing agents (especially stabilized bisulfite or hydroxylamine salts) can be employed because they do not affect the dyes used. 

The hue or vividness of colour may be correlated with the intensities of the absorption bands. Thus, Al-Fe epidotes, with relatively low molar extinction coefficients typical of spin-forbidden transitions within Fe3+ ions ( 3.7.2), exhibit pastel shades. The Al-Mn-Fe epidotes, however, display vivid colours correlating with high e values and originating from spin-allowed transitions within Mn3+ ions located in the very distorted acentric octahedral M3 site (fig. 

Cations of the lanthanide elements also produce colours in some minerals through intra-electronic transitions within 4/orbitals (Adams, 1965 Bernstein, 1982). Absorption bands are usually sharp and weak, leading to pastel shades. Examples of such coloured minerals are monazite, bastnaesite, rhabdophane, xenotime, gadolinite, and certain apatites, calcites, scheelites and fluorites. As noted earlier, some rare earth-bearing minerals, notably fluorite and monazite, also display the alexandrite effect (Berstein, 1982 Schmetzer et al., 1980). 

Yellowing is a serious concern for the textile industry. A high proportion of cases falls into the category of yellowing during storage or in transport. The problem is naturally most prevalent with textiles that are white or have only a pastel shade. It has been stated that there are more than 20 possible causes of such yellowing.544... 

Imparts a soft, lofty, non-greasy handle to textile fibres. Excellent non-yellowing properties and no effect on dyed shades therefore especially suitable for application to pastel shades and optic whites. Can be applied from resin baths. 

Non-yellowing, especially effective on bleached whites and pastel shades. 

Alcoholic fine fragrance. Contains 90% denatured, cosmetic-grade ethanol. Possibly lightly coloured (maybe a pastel shade). 

UF is made by the condensation polymerisation of urea and formaldehyde. Although it has been widely used for closures (mainly in pastel shades), use is now in decline due to wadless thermoplastic systems. Density 1.47-1.52. 

Appearance is only a guide to the type of plastic present because various fillers and colouring materials can change the appearance of a polymer considerably. However, Bakelite (phenol-formaldehyde) is always brown, black or red, while urea- and melamine-formaldehydes may have pastel shades. Polyethylene and polypropylene always appear slightly cloudy as thin films, while most other colourless plastics, particularly polyesters and polycarbonate, are crystal clear. 

Up to 10% of pigment by weight of cement may be added depending on the depth of colour required. Used with white Portland cement it is possible to produce pastel shades. 

Amino resins are related polymers formed from formaldehyde and either urea or melamine. In addition to many of the uses listed earlier, they can be used to manufacture lightweight tableware, and counter and table surfaces. Being transparent they can be filled and colored using light pastel shades, whereas the phenohcs are already rather dark and, consequently, have a more restricted color range. 

Uses Flame retardant for transparent or pastel-shaded plastics and coatings... 

---