No. 1031 - Miljøstyrelsen

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22 • Fluids; • Elastomers; • Resins. Silicone fluids Silicones generally increase in viscosity with increasing chain length. In silicone fluids, the number of dimethylsiloxane moieties (indicated by the "n" in the chemical formulae) is up to 4000 (Ullmann 2003). Silicone fluids are distinguished from common organic fluids by a number of unique properties (Ullmann 2003): • Good thermal stability (150-200°C); • Good low-temperature performance (
Curing of one-component RTV silicones starts when the compounds are exposed to atmospheric moisture during application. The crosslinking agents are tri- or tetrafunctional silanes containing hydrolyseable Si-O or Si-N bonds. Depending on the used cross-linking agent different compounds are formed as cleavage product and will be released during the curing process (see Table 1.1) Well known is the smell of acetic acid, when silicone sealants with ethyltriacetoxysilane as cross-linking agent are applied. The acetic acid is formed by the curing process. Table 1.1 Crosslinking agents and cleavage products for curing of silicone elastomers ( based on Ullmann 2003) Cross-linking agent Cleavage product Alkoxysilanes Alcohols Methyl- or ethyltriacetoxysilane Acetic acid Tris(cyclohexylamino)methylsilane and others Amines Methyl(tributanone oximo)silane Butanonoxime Benzamide silanes N-butylbenzamide and ethanol Silicone elastomers are characterised by excellent electrical insulating properties, inertness, low toxicity and resistance to ozone, weathering, oil and moisture. Some grades have the ability to perform at very low temperatures, whereas others retain elastomeric properties at very high temperatures. Unfilled silicone elastomers achieve only low mechanical strength when cured. Adequate strength is obtained by incorporating reinforcing fillers. Smallparticle-size, silicas are used almost exclusively for this purpose. Because of the small particle size elastomers with high transparency can be produced. The major application of silicone elastomers is as sealant, but they are also widely used for other applications like electrical fittings, textile coating, paints and rubbers for automotive, medical and dental purposes. Silicone resins Whereas silicone fluids and elastomers are based on cyclic or linear polymers, silicone resins are highly branched polymers. Compared to the fluids and elastomers, the market of silicone resins is limited. The major market for silicone resins is surface coatings, mainly waterrepellant coatings for masonry and high-performance paints. For these purposes the silicone resin is often reacted with other polymers to form copolymers. Silicone/alkyd and silicone/polyester are the most frequently used. 1.2 International market Ethyltriacetoxysilane C CH3 Globally the consumption of siloxanes totals about 0.85 million tonnes (Will et al 2003). The main producer countries are the USA, Germany, Japan, France and the UK. The American producer DOW Corning Corporation is O H5C2 O Si O O C CH3 O C CH3 O 23
Page 1 and 2: Siloxanes - Consumption, Toxicity a
Page 3 and 4: Table of Contents PREFACE 5 SUMMARY
Page 5: Preface Siloxanes, the building blo
Page 8 and 9: 8 products, clothes, health-care pr
Page 10 and 11: 10 A possible estrogenic effect con
Page 13 and 14: Sammenfatning og konklusioner Denne
Page 15 and 16: Udledninger til miljøet Den væsen
Page 17 and 18: Prisen på alternativerne varierer
Page 19 and 20: 1 Introduction 1.1 What are siloxan
Page 21: Cyclic siloxanes with other functio
Page 25 and 26: Table 1.2 Consumption of silicones
Page 27 and 28: tion and export of siloxanes regist
Page 29 and 30: CAS No. Name Import average tonnes
Page 31 and 32: • Defoamers, flow control agents
Page 33 and 34: Besides their technical properties,
Page 35 and 36: paint, coatings and waxes in total
Page 37 and 38: Table 2.5 Siloxanes in imported, ex
Page 39 and 40: Fate of the siloxanes The siloxanes
Page 41 and 42: • Mouldmaking (reproduction of co
Page 43 and 44: The main source of releases of silo
Page 45 and 46: • Immunotoxicity studies. Human c
Page 47 and 48: LD 50 following dermal application
Page 49 and 50: cinogenic hazard associated with D5
Page 51 and 52: following repeated exposures, the l
Page 53 and 54: Table 4.1 PBT profiler results for
Page 55 and 56: 5 Alternatives The use of some type
Page 57 and 58: Name of alternative Neopentylglycol
Page 59 and 60: 5.1.7 Summary and general experienc
Page 61 and 62: Table 5.2 Identified alternatives t
Page 63 and 64: References Allan, R.B., Kochs, P. &
Page 65 and 66: EPA DCN 86970000024. 1996. Pharmaco
Page 67 and 68: EPA, August 2003. Siloxane D5 in Dr
Page 69 and 70: 69 Annex 1 Siloxanes listed in the
Page 71 and 72: 71 INCI name CAS No EINECS/ ELINCS
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73 INCI name CAS No EINECS/ ELINCS
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Declared name CAS No. ACRYLATES / D
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Annex 3 Siloxanes in the Danish Pro
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Tonnes siloxanes Import Production
Page 85 and 86:
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tonnes siloxanes Import Production
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Annex 5 Siloxanes in cleaning and m
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tonnes siloxanes Import Production
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Annex 7 Database screening for deca
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Inhalation No relevant data found O
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PhysProp 2003. PHYSPROP DEMO-databa
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10 CAS no Synonym Test Exposure rou
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103 CAS no Synonym Test Exposure ro
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111 CAS no Synonym 556-67-2, 541-02
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No. 1031 - Miljøstyrelsen

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