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Applying diamond-like coatings to plastics and rubber
November 1999
ments such as the human genome project and physiological modelling, is contained in a series of reports prepared by Government departments and agencies, and by Research Councils concerned with chemical safety. Recommendations of the Interdepartmental Group on Health Risks from Chemicals will contribute to modernizing the process of risk assessments, and partnerships are sought which will take this forward. Chairman Dr David Shannon said that information emerging from the human genome project may allow the population to be considered as a series of sub-groups who might be genetically more or less sensitive to a particular chemical. “It might even be possible,” he added, “to identify the genes that convey sensitivity to a particular group of chemicals, and use this information to offer more effective risk management options”. Practical results of the programme could be a reduction in animal testing, because of greater shared knowledge, and reduced research costs for companies. The reports are: Developing new approaches to assessing risk to human health from chemicals: Risk assessment approaches used by the UK Government for evaluating human health effects of chemicals; Risk assessment strategies in relation to population subgroups; Physiologically-based pharmacokinetic modelling: a potential tool for use in risk assessment; Exposure assessment in the evaluation of risk to human health; From risk assessment to risk management: dealing with uncertainty. Copies of the reports are available from the Institute for Environment and Health, which was established at the University of Leicester by the Medical Research Council in 1993. Contact: Institute for Environment and Health, University of Leicester, 94 Regent Road, Leicester LEI 700, UK
0 I 999 Elsevier Science
Additives for Polymers
NEW EQUIPMENT Hand-held instrument measures colour at all stages A new hand-held instrument to measure colour quickly, easily and accurately on almost any type of surface - claimed to be the only such device - was demonstrated by GretagMacbeth at the recent UK plastics exhibition, Interplas. The ColorEye XTH spectrophotometer enables plastics manufacturers and processors to measure both sample stepped chips and finished products, so ensuring consistency throughout the processing operation, Unlike heavier instruments, it can easily be used to check the colour at any stage. The sphere-based instrument incorporates unique XT5 technology, which uses a twodimensional CCD to capture five frames (or channels) of measurement data simultaneously. The company also featured its ProPalette colour formulation and Optiview colour quality software. Contact: GretagMacbeth Ltd, Pacific Road, Altrincham WA14 5BJ UK; tel: +44-161 926 9822; fax: +44-161 926 9835
TECHNOLOGY Applying diamond-like coatings to plastics and rubber By using chemical vapour deposition (CVD) technology at a relatively low temperature, Nissin Electric Co, Kyoto, Japan, claims it is able to apply diamond-like carbon coatings to materials such as plastics and rubber, improving their properties of friction, abrasion resistance and insulation. Conventionally, this type of coating is applied by plasma at a temperature of about 2OO”C,which has limited its application of surfaces such as metals and ceramics. The CVD technology, however, enhanced by a plasma source operated only intermittently (PECVD), can function at around 50-80°C. Combined with plasma washing in a specific atmospheric gas, it has been
7
Additivesfor Polymers
possible to coat thermoplastic materials with much lower softening points. Surface properties (such as sliding friction, abrasion resistance and insulation) that are claimed to be equal to, or better than, fluorinetreated surfaces, and can be achieved at lower cost. In addition, the coated surfaces have good long-term reliability. Nissin also reports that it has developed a flexible diamond-like coating, which can be stretched up to 300%. Contact: Nissin Electric Co Ltd, 47 Umezutakase-cho, Ukyo-ku, Kyoto 615, Japan; tel: +81-75 861 3151; fax: +81-75 872 0742
ASTM to extend the scope of colour stability test To enhance the prediction of light stability of plastics, the ASTM is revising its Standard D 4674. Entitled Test Method for Accelerated Testing for Color Stability of Plastics Exposed to Indoor Fluorescent Lighting and WindowFiltered Daylight, determines the resistance to a
plastic compound to colour change in a typical office environment, under prevailing illumination conditions. The current test method specifies the use of cool white fluorescent lamps and UVB-313 sun lamps. The revision, according to Patrick Brennan, Chairman of the ASTM Subcommittee D20.50 on Durability, responsible for the standard, will admit to the test procedure other types of interior lighting sources, which will allow the method to be used to simulate a number of indoor environments. Contact: American Society for Testing and Materials - ASTM, 100 Barr Harbor Drive, West Conshocken, PA 19428-2959, USA; tel: i-l-610 832 9500; fax: +l-610 832 9635
TECHNICAL BRIEFS Use of melamine with other minerals as flame retardants The addition of melamine to mineral filler fire retardants for PP generally improves the UL94 8
November 1999
behaviour, eliminating at the same time the afterglow phenomenon which is typical of mineral fillers used alone. Unfortunately, this additive is not sufficiently thermally stable and requires special precautions in processing, which still have to be improved. Melamine also reduces the specific weight of fire retarded PP which results in an economical advantage and allows the use of relatively cheap inert fillers such as kaolin and talc which, used alone, do not show fire retardant effect. A group of researchers at PP manufacturer Monte11and Turin University has been studying the optimum mix of melamine with other mineral tillers, to obtain the best balance of properties. They reported their results at the recent EuroFillers ‘99 Conference. Melamines must be employed at a large loading (up to 65% by weight) to meet adequate fire retardance effectiveness, with possible reduction of physico-mechanical performances of end products. Melamine as well is used as an organic filler to fire retard polymeric materials which particularly improves UL94 behaviour of polypropylene (PP) when used at the same overall loading. However introduction of melamine or inorganic fillers causes processing and compounding difficulties. For all fillers examined, the mixtures containing 40% of melamine and 25% of mineral filler (ratio 60/40 w/w) showed the best compromise between Oxygen Index and UL94. Magnesium and aluminium hydroxides specially coated with ZHS confer significantly increased combustion resistance and lower levels of smoke evolution to these polymers. This permits large reductions to additive loading relative to unmodified filler, without sacrificing flame retardant or smoke suppressant performance. Melamine is the most effective tire retardant- in terms of UL94 leading to a VO rank at 45% of loading. 60% of Al(OHb leads to a VO rank and 60% of Mg(OH)z to a Vl rank. It is necessary to increase the loading at 65% in order to get a Vl behaviour using MgC03. Talc and kaolin are ineffective up to 75% of loading. The situation is different for Oxygen Index criteria: Al(OH)3 and Mg(OH)z are the most effective and talc and kaolin (which only act as a diluent)
0 1999 Elsevier Science
ments such as the human genome project and physiological modelling, is contained in a series of reports prepared by Government departments and agencies, and by Research Councils concerned with chemical safety. Recommendations of the Interdepartmental Group on Health Risks from Chemicals will contribute to modernizing the process of risk assessments, and partnerships are sought which will take this forward. Chairman Dr David Shannon said that information emerging from the human genome project may allow the population to be considered as a series of sub-groups who might be genetically more or less sensitive to a particular chemical. “It might even be possible,” he added, “to identify the genes that convey sensitivity to a particular group of chemicals, and use this information to offer more effective risk management options”. Practical results of the programme could be a reduction in animal testing, because of greater shared knowledge, and reduced research costs for companies. The reports are: Developing new approaches to assessing risk to human health from chemicals: Risk assessment approaches used by the UK Government for evaluating human health effects of chemicals; Risk assessment strategies in relation to population subgroups; Physiologically-based pharmacokinetic modelling: a potential tool for use in risk assessment; Exposure assessment in the evaluation of risk to human health; From risk assessment to risk management: dealing with uncertainty. Copies of the reports are available from the Institute for Environment and Health, which was established at the University of Leicester by the Medical Research Council in 1993. Contact: Institute for Environment and Health, University of Leicester, 94 Regent Road, Leicester LEI 700, UK
0 I 999 Elsevier Science
Additives for Polymers
NEW EQUIPMENT Hand-held instrument measures colour at all stages A new hand-held instrument to measure colour quickly, easily and accurately on almost any type of surface - claimed to be the only such device - was demonstrated by GretagMacbeth at the recent UK plastics exhibition, Interplas. The ColorEye XTH spectrophotometer enables plastics manufacturers and processors to measure both sample stepped chips and finished products, so ensuring consistency throughout the processing operation, Unlike heavier instruments, it can easily be used to check the colour at any stage. The sphere-based instrument incorporates unique XT5 technology, which uses a twodimensional CCD to capture five frames (or channels) of measurement data simultaneously. The company also featured its ProPalette colour formulation and Optiview colour quality software. Contact: GretagMacbeth Ltd, Pacific Road, Altrincham WA14 5BJ UK; tel: +44-161 926 9822; fax: +44-161 926 9835
TECHNOLOGY Applying diamond-like coatings to plastics and rubber By using chemical vapour deposition (CVD) technology at a relatively low temperature, Nissin Electric Co, Kyoto, Japan, claims it is able to apply diamond-like carbon coatings to materials such as plastics and rubber, improving their properties of friction, abrasion resistance and insulation. Conventionally, this type of coating is applied by plasma at a temperature of about 2OO”C,which has limited its application of surfaces such as metals and ceramics. The CVD technology, however, enhanced by a plasma source operated only intermittently (PECVD), can function at around 50-80°C. Combined with plasma washing in a specific atmospheric gas, it has been
7
Additivesfor Polymers
possible to coat thermoplastic materials with much lower softening points. Surface properties (such as sliding friction, abrasion resistance and insulation) that are claimed to be equal to, or better than, fluorinetreated surfaces, and can be achieved at lower cost. In addition, the coated surfaces have good long-term reliability. Nissin also reports that it has developed a flexible diamond-like coating, which can be stretched up to 300%. Contact: Nissin Electric Co Ltd, 47 Umezutakase-cho, Ukyo-ku, Kyoto 615, Japan; tel: +81-75 861 3151; fax: +81-75 872 0742
ASTM to extend the scope of colour stability test To enhance the prediction of light stability of plastics, the ASTM is revising its Standard D 4674. Entitled Test Method for Accelerated Testing for Color Stability of Plastics Exposed to Indoor Fluorescent Lighting and WindowFiltered Daylight, determines the resistance to a
plastic compound to colour change in a typical office environment, under prevailing illumination conditions. The current test method specifies the use of cool white fluorescent lamps and UVB-313 sun lamps. The revision, according to Patrick Brennan, Chairman of the ASTM Subcommittee D20.50 on Durability, responsible for the standard, will admit to the test procedure other types of interior lighting sources, which will allow the method to be used to simulate a number of indoor environments. Contact: American Society for Testing and Materials - ASTM, 100 Barr Harbor Drive, West Conshocken, PA 19428-2959, USA; tel: i-l-610 832 9500; fax: +l-610 832 9635
TECHNICAL BRIEFS Use of melamine with other minerals as flame retardants The addition of melamine to mineral filler fire retardants for PP generally improves the UL94 8
November 1999
behaviour, eliminating at the same time the afterglow phenomenon which is typical of mineral fillers used alone. Unfortunately, this additive is not sufficiently thermally stable and requires special precautions in processing, which still have to be improved. Melamine also reduces the specific weight of fire retarded PP which results in an economical advantage and allows the use of relatively cheap inert fillers such as kaolin and talc which, used alone, do not show fire retardant effect. A group of researchers at PP manufacturer Monte11and Turin University has been studying the optimum mix of melamine with other mineral tillers, to obtain the best balance of properties. They reported their results at the recent EuroFillers ‘99 Conference. Melamines must be employed at a large loading (up to 65% by weight) to meet adequate fire retardance effectiveness, with possible reduction of physico-mechanical performances of end products. Melamine as well is used as an organic filler to fire retard polymeric materials which particularly improves UL94 behaviour of polypropylene (PP) when used at the same overall loading. However introduction of melamine or inorganic fillers causes processing and compounding difficulties. For all fillers examined, the mixtures containing 40% of melamine and 25% of mineral filler (ratio 60/40 w/w) showed the best compromise between Oxygen Index and UL94. Magnesium and aluminium hydroxides specially coated with ZHS confer significantly increased combustion resistance and lower levels of smoke evolution to these polymers. This permits large reductions to additive loading relative to unmodified filler, without sacrificing flame retardant or smoke suppressant performance. Melamine is the most effective tire retardant- in terms of UL94 leading to a VO rank at 45% of loading. 60% of Al(OHb leads to a VO rank and 60% of Mg(OH)z to a Vl rank. It is necessary to increase the loading at 65% in order to get a Vl behaviour using MgC03. Talc and kaolin are ineffective up to 75% of loading. The situation is different for Oxygen Index criteria: Al(OH)3 and Mg(OH)z are the most effective and talc and kaolin (which only act as a diluent)
0 1999 Elsevier Science