January 1993 Additives for Polymers

Colorant system for polyurethane foams

Reactint colorants from Milliken Chemical are based on proprietary Milliken polymer- bound colour technology. Unlike pigments, they are liquid in nature and non-particulate. They do not act as a contaminant or nucleant, so they do not interfere with foam chemistry and do not create voids or pinholes. Because they are soluble liquids, they are easy to use and clean up.

Reactint colorants are available in five primary colours, which can be combined at the mix head with a colour system to create any desired colour for urethane foams. The Reactint Colour System provides short turnaround times, instant blendability and reduced maintenance. The system is ideal for flexible, rigid and semi-rigid urethane (polyether and polyester) foams. Contuct: Milliken Chemicals, PO Box 1927 M-400, Spartanburg, SC 29304-1927, USA. Tel: + l-803-573-2200. Fux: + 1-803-573- 2430. Or Milliken Europe NV, 18 Ham, B- WOO, Gent, .Belgium. Tel: +32-91-236081. Fax: i- 32-91-238564.

Supplier of fluorescent colorants

Lawter International in the USA now supply fluorescent colorants under the trade name Thermochrome. These pigments do not contain formaldehyde. Contuct: Luwter Imternational, 990 Skokie Blvd., Northbrook, IL 60062, USA.

Plascoat colour matching facilities

A state-of-the-art computer-controlled colour matching unit has been installed by Plascoat in the UK to keep pace with market demand -

particularly for its Flexible Moulding Division products. Plascoat’s latest computer upgrade means that the company now has one

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of the most sophisticated colour matching facilities in the industry, with a capability which extends well beyond RAL standard colours. Contact: Plascoat Systems Ltd., Farnham, Surrey, GU9 9NY, UK. Tel: +44-252- 733 777. Fax: -I- 44-252- 725719.

Waxes for mass colouring of polypropylene for yarns and fibres

BASF has developed two new polypropylene- based waxes for pigment preparations used for mass colouring of polypropylene for yarns and fibres. These products, designated Luwax ES 9673 and Luwax ES 9674, make it possible to disperse relatively coarse pigment clusters very finely throughout the plastic. As a result the colorant is not only exploited better, but the clogging of filters and spinnerettes by large pigment particles is also prevented.

The new products are fully compatible with the polypropylene to be dyed; thus, the waxes do not affect the mechanical strength of the fibres. Tears occur far less frequently in the spinning process than with less compatible additives. Moreover, the good temperature and ultraviolet light stability provided by Luwax ES 9673 and ES 9674 contribute significantly to the long-term wearability of polypropylene fibres and yarns. Contact: BASF AG, D-6700 Ludwigshafen, Germany. Tel: +49-621-60-99223. Fax. +49-621-60-20129.

PROCESSING

Blending ten additives via one- pack granules

EniChem Synthesis SpA, is said to have advanced one-pack technology with a process

Additives for Polymers January 1993

that permits the addition of up to 10 materials, many of which, until now, could only be dosed separately.

The product, a free-flowing granule, combines UV stabilizers, heat stabilizers, and other additives with a phenolic antioxidant base. It is part of a new family of additive formulations called No Dust Blend. The Milan, Italy, company does not disclose details about the technology, because a patent is pending. However, it is said that the key to the process is the use of phenolic antioxidants, which act as a glue to bind additives within the granule. Blends can be tailored to meet individual process requirements. Contact: Enichem Synthesis SPA, Strade 2, Palazzo F7, Milanofiori I-20094, Assago, MI, Italy. Tel: -I- 39-52-01. Fax: + 39-52-02-6684.

Processing aids for re-processing starch-filled plastics

Processing aids for extrusion and re- processing of starch-filled and conventional resins, have been introduced by Ecostar International. They are designed primarily, but not exclusively, to work with Ecostar Plus, a modified-starch additive system that allows conventional polymers to bio- and photodegrade. “E-flow extrusion aid” reportedly boosts output rates - by up to 50% with LLDPE, for example - and eliminates melt fracture in a variety of polythene blown films. It comes in masterbatch form with customized loadings. A second new masterbatch, E-flow desiccant, removes moisture when re-processing starched-tilled polythene. The company says these products eliminate two potential sources of processing difficulties with Ecostar Plus. Contact: Ecostar International, Tonawanda, NY, USA.

Mixing teeth improve glass compounding

Using a relatively new toothed mixing element for compounding glass-reinforced polymers, reportedly can maximize both physical properties and process stability. Werner & Pfleiderer Corp has introduced what is termed the “ZME self-wiping distributive mixing element” which allows compounders to maximize the physical properties of a reinforced thermoplastic using dies with relatively high L/D ratios (ratio of land length to hole diameter). Contact: Werner & Pfleiderer Corp, 663 E. Crescent Ave, Ramsey, NJ 07446, USA. Tel. + l-201 -32 7-6300.

TECHNICAL BRIEFS

Thermal degradation of short Kevlar fibre-thermoplastic polyurethane composites

Results of a study by the Cochin University of Science and Technology, Kochi, India, show the thermal degradation of these composites takes place in two steps. Short Kevlar fibre improves the thermal stability of thermoplastic polyurethane, the optimum loading being 20 phr. The degradation of thermoplastic polyurethane and Kevlar- thermoplastic polyurethane composite follows first-order kinetics. Polymer Degradation & Stability, 1992, 38, (31, 187-192

Antioxidants and light stabilizers

Reactions of indoline nitroxide and phenoxy radicals. X-ray crystallographic analysis of l- [0-(3,5-di-tert-butyl-4-hydroxy)-benzyll-1,2- dihydro-2-methyl-2-phenyl-3-oxo-3H-indole and 3,5,3’5’-tetra-rcrr-butylstilbene-4,4’- quinone. Polymer Degradation & Stability, 1993, 39, (I), 73-83

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