Plastic materialities 26-27 colour

Casein is the only protein that has achieved commercial significance as a plastics raw material. Many other proteins are readily available in many vegetable material residues which arise from such processes as the extraction of oils and starches from seeds. It would be advantageous to countries possessing such residues if plastics could be successfully exploited commercially. Although plastics materials have been produced they have failed to be of value since they are invariably dark in colour and still have the water susceptibility and long curing times, both of which are severe limitations of casein. 

Nowadays, however, zinc-coated steel sheets, either continuously galvanised or electroplated, are often used as a basis material for overcoating with plastic materials or paints. The coatings are usually applied continuously and have a range of uses both externally and internally. Many surface finishes are obtainable, e.g. plain or embossed, and in an extensive range of colours, to suit almost any requirement . 

Specific grades of carbon and steel fibres are especially marketed as additives for conductive plastics allowing resistivities of roughly 10 ohm.cm to be obtained. The other properties of the final material - colour, modulus, impact strength. .. are modified. Carbon fibres have a large reinforcing effect. 

ISO 105-X10 Textiles - Tests for colour fastness - Part XIO Assessment of migration of textile colours into polyvinyl chloride coatings ISO 264 1976 Unplasticized polyvinyl chloride (PVC) fittings with plain sockets for pipes under pressure - Laying lengths - Metric series ISO 265-1 1988 Pipes and fittings of plastics materials - Fittings for domestic and industrial waste pipes - Basic dimensions Metric series - Part 1 Unplasticized poly(vinyl chloride) (PVC-U)... 

European Commission On the Use of Colourants in Plastic Materials Coming in Contact with Food, Resolution AP (89) 1., Sept. 13, 1989. 

In 1909, Leo Baekeland, a Belgian chemist, patented the process for manufacturing a plastic material called bakelite. When phenol and formaldehyde are heated together in alkaline solution, they combine to form an amber coloured resin-like solid called resinoid. 

During the period between the first and second world wars a plastics business was developed based upon rennet casein from cow s milk, from soya beans or other pulses the reaction with formaldehyde gave a rigid plastic material which could be produced in light colours, mottle and pearlescent effects, and was capable of being machined and polished to a high gloss. 

Method. Portions of red and yellow coloured HDPE, polypropylene, PET and clear PMMA plastic materials are comminuted into sizes approximately 4x4 mm using a diamond edge cutter. 

Ultraviolet absorbers absorb primarily in the UV range while avoiding absorption in the visible hght range so that the appearance of the plastic material s colour is not changed. Once absorbed, UV radiation may be converted to heat or to new chemical products. The most important commercial absorbers include o-hydroxybenzophenones, o- hydroxyphenylbenzotriazoles and sahcylates. These convert absorbed radiation to heat. 

Stimulus cards were made by sticking 4 cm squares of thin coloured washable plastic material onto blank playing cards. Standard packs of 24 cards were made up for Ae four experimental conAtions employed A, B, C and D. In conAtion A a pack of cards was made up of cards of two colours, 12 of each. In conAtion B a pack was made up of four colours, 6 cards of each in C six colours, 4 cards each and in D Aere were eight colours wiA 3 cards for each. A pack of blank cards was used to obtain movement times in each of Ae four conAtions. Thus for pack A Ae choice was between 2 stimuli, and for B, C and D respectively 4,6 or 8 stimuli. 

The measurement of melt mass-flow rate and density is usually the first step in the specification and identification of polyethylene materials. It should be noted that the density of the base polymer differs from the density of the finished geomembrane mixed with carbon black. The confusion, which can occur in the classification of the PE resin, has briefly been dealt with in Sect. 2.1. As a rule, only geomembianes coloured black by carbon black, and not their natural-coloured resin, reach a density which properly meets the classification of HOPE plastic material (see Sect. 2, Tables 2.2 and 2.3). However, one may not consider these classification limits as strict technical criteria even if the density of the black geomembianes is just below 0.940 g/cm, it may correspond to what is ealled HOPE geomembrane over the whole spectrum of its characteristics. 

Products, normally used in small quantities, which enhance the value of materials such as plastics, paints, colour prints, and lubricants, by improving their processability, performance, and appearance during manufacture and in use. 

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