Brominated Flame Retardants

2. Uses in Denmark

2.1 Chemicals and Semi-manufactures
2.1.1 Import, Export and Production as Chemicals
2.1.2 Consumption with Plastic Compounds and Masterbatches
2.1.3 Consumption with Plastic Semi-manufactures
2.1.4 Consumption with Electronic Semi-manufactures
2.1.5 Emission from Production Processes in Denmark
2.1.6 Summary
2.2 Use in Manufactured Goods
2.2.1 Printed Circuit Boards
2.2.2 Housing of Electric and Electronic Equipment
2.2.3 Other Components of Electric and Electronic Appliances and Machines
2.2.4 Lighting
2.2.5 Wiring and Power Distribution
2.2.6 Textiles
2.2.7 Building Materials
2.2.8 Paints and Fillers
2.2.9 Transportation
2.2.10 Other Uses
2.2.11 Summary
2.3 Unintended Uses as Contaminant

2.1 Chemicals and Semi-manufactures

To make it clear where different parts of the materials life cycle will be described in the report, the flow of substances is illustrated in figure 2.1., exemplified by the flow of TBBPA from the production of the chemical to disposal of electronics.

Figure 2.1
Material flow of TBBPA with electronics

In all steps there may be emissions of TBBPA to the environment and production of waste.

The substances are imported to Denmark as pure chemicals, in compounds, in semi-manufactures as laminates and printed circuit boards, in finished goods and finally in waste product. Likewise the substances can be exported in compounds, semi-manufactures, finished goods and waste products.

According to the paradigm /12/ only the consumption with manufactured products (e.g. 'consumption of electronics' in figure 2.1) is included in the total consumption figures in section 4. The consumption of TBBPA for the different production processes is mainly assessed in order to estimate emissions and waste production from the processes.

2.1    Chemicals and Semi-manufactures

2.1.1    Import, Export and Production as Chemicals

Import, export and production of brominated flame retardants as chemicals according to the trade statistics from Statistics Denmark /29 / are shown in table 2.1. Commodity data for brominated flame retardants and other bromine compounds for the period 1993-1998 are compiled in appendix 7 (not included in the printed version).

The statistic data include the high volume aromatic brominated flame retardants as PBDEs, TBBPA and TBBPA derivatives.

The net supply of these compounds in 1997 totals 29 tonnes.

Vinylbromide is not included in table 2.1 as this compound in the statistics is registered under the same commodity position as dibromoethane that is used in high quantities as gasoline additive.

Hexabromocyclododecane will be registered under the commodity position ''Halogen derivatives of other cycloalkanes, -alkenes -terpenes'. The import and export of these chemicals were 0 tonnes in 1997.

Other brominated flame retardants may be registered under commodity positions including other halogenated compounds, but it is supposed that the compounds included in table 2.1 represent the chief part of the supply of brominated flame retardants as chemicals.

The chemicals are used for compounding in Denmark. According to information from compounders it is estimated that most of the flame retardants used by compounders are reexported with compounds and masterbatchs.

It is possible that the 9 tonnes ester or anhydride of tetrabromophthalic acid is TBPA derivatives used for production of PUR foam in Denmark and thus included in the consumption with plastic raw materials in the next section, but this use has not been confirmed. It cannot be excluded that a part of the other chemicals is used by companies that use the chemicals directly in the production of plastic products, but no consumption for these purposes has been identified.

Table 2.1
Import, export and production of brominated flame retardants as chemicals in Denmark 1997 according to the trade statistics 4)

Bromine derivatives of aromatic ethers

The net supply of bromine derivatives of aromatic ethers, including the PBDEs, has decreased from about 20 tonnes per year in the period 1993-1995 to around 1 tonne in 1997 (figure 2.2). The decrease in the supply of PBDEs is in accordance with the general trend in the use of these substances.

Figure 2.2
Net supply of bromine derivatives of aromatic ethers 1993-1997 (based on appendix 7).

The net supply of pentabromomethyl benzene has in the period 1995-1997 been around 10 tonnes per year. Before 1995 the compound was registered under a commodity position including non-bromine compounds.

Other bromine compounds

The total import of bromine chemicals in 1997 was around 700 tonnes. Of these ethylene dibromide and vinylbromide accounted for 264 tonnes (presumably ethylene dibromide) and methylbromide accounted for 385 tonnes. Ethylene dibromide (EDB) is used as gasoline additive, and the import has increased markedly during the nineties.

2.1.2  Consumption with Plastic Compounds and Masterbatches

The bulk import/export of bromine containing plastic compounds are in the trade statistics registered under commodity positions including non-bromine containing compounds, and it is consequently not possible to determine the import from the statistical data.

Only brominated polystyrene (PS) is registered separately. According to the trade statistics from Statistics Denmark /29/ there was in 1997 an import of 2 tonnes brominated PS (58-71% bromine content W/W) and an export of 9 tonnes. Until 1997, brominated PS was registered under other commodity positions.

Supply

The total net supply of brominated flame retardants with polymer compounds and masterbatches in Denmark in 1997 is estimated at 130-190 tonnes (see table 2.2). The estimate is based on a questionnaire survey including 60 dealers of plastics compounds and large companies with direct import. The survey was performed in collaboration with the Danish Plastic Federation. More than 95% of the interviewees responded to the questionnaire.

Table 2.2
Import of brominated flame retardants with plastic compounds and masterbatches for production in Denmark 1997

The brominated flame retardants were used in approximately 1,300 tonnes of polymer compounds. All masterbatches and compounds are imported.

TBBPA and derivatives accounted for about 24% of the total consumption of BFRs with polymer compounds and masterbatches. The TBBPA was used as reactive FR for unsaturated polyester (UPE), and as additive FR for polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). Additive use accounted for approximately 99% of the TBBPA in plastic compounds.

Most of the TBBPA was used in PET/PBT for production of plugs and switches for wiring, and switches, electrogates and other parts for electronics and electric appliances and machines.

About 3 tonnes TBBPA was used in ABS for housing of telecommunication devices and about a half tonne was used in unsaturated polyester for production of laminates.

PBDEs were only used in PE compounds for production of PE-film for building applications.

HBCD was used for expanded polystyrene (EPS) for insulation sheets and for high impact polystyrene (HIPS) used for distribution boxes for wiring.

Polybrominated biphenyl was used in thermoplastic polyesters (PBT/PET) used for plastic parts in contact with live parts of electric appliances and machines.

Brominated polyetherpolyol accounting for approximately 63% of total consumption is used for PUR insulation for cold stores, refrigerator ships and containers, etc.

Other brominated compounds include brominated polystyrene in polyamide and dibromopentyl glycol in unsaturated polyester.

Trend

From 1990 there has been a trend away from the use of PBDEs in Danish production of plastic products. The PBDEs have partly been substituted by TBBPA, partly by non-brominated flame retardants.

In housings for home electronics and medical appliances, PBDE containing ABS systems has to a large extent been substituted by non-brominated ABS/PC systems, and bromine containing ABS was in 1997 only used for telecommunication devices.

The development has to some extent been forced by working environmental considerations - but the driving force has not been the brominated flame retardants. In ABS systems used for housings, brominated diphenyl ethers have traditionally been used in combination with antimony trioxide. Antimony trioxide is in EU classified as carcinogenic (R40) and in accordance with Danish regulations /30 / carcinogenic compounds are to be substituted if possible.

Bromobutyl rubber   

Brominated compounds are used for production of bromobutyl rubber. The brominated compound is not used for flame retardancy of the rubber and will not be included in this study.

Flame retardancy of rubbers is mostly obtained by the use of chlorinated compounds, antimony trioxide, lime and other fillers, but brominated compounds may be used as well. It has not been possible to identify any consumption of brominated flame retardants for production of rubber in Denmark.

According to an American producer, brominated flame retardants have been used in a variety of rubbers. Typical applications include seals, belts, tubing, wire and cable insulation, roofing, coated fabrics, and sponge.

2.1.3  Consumption with Plastic Semi-manufactures

Plastic semi-manufactures of BFR containing ABS, PE, PS, PP and PC are imported for production processes in Denmark.

The bulk part is sheets of ABS and PS for vacuum forming of components for EE appliances and the transportation industry, but also foils, pipes and bars are used.

Based on information from two leading dealers of plastic semi-manufactures the total import of flame retarded semi-manufactures are estimated at 10-20 tonnes ABS, 5-10 tonnes PS and 5-10 tonnes PE, PP and PC. Included in the estimates is direct import by manufacturers.

The used flame retardants are not known, but it is roughly estimated that most ABS is flame retarded with TBBPA, PS with HBCD and the rest with other brominated flame retardants.

In total the consumption of BFRs with plastic semi-manufactures is estimated at at 2-5.2 tonnes TBBPA, 0.1-0.3 tonnes HBCD, and 0.5-1.5 other BFRs.

2.1.4  Consumption with Electronic Semi-manufactures

Brominated flame retardants are imported with laminates for production of printed circuit boards in Denmark.

Brominated flame retardants are also imported with other semi-manufactures: Electronic components, sockets, switches, etc., but the use of these semi-manufactures is estimated not to generate waste or emissions to the environment and consequently not included in this part of the analysis.

The laminates are estimated to account for the major part of BFRs with semi-manufactures.

Laminates for printed circuit boards

In the following section terms that will be explained in more detail in section 2.2.1 will be anticipated.

There is no Danish production of laminates for printed circuit boards. The laminates are mainly imported from Sweden or Germany.

The Danish production of printed circuit boards is in the trade statistics only registered in terms of the value of the production, whereas import and export are registered with both value and weight. The weight of the production can broadly be estimated from the value/weight ratio of the export.

Using this ratio, the production of unassembled boards can be estimated at approximately 710-1100 tonnes. The laminates for the production are presumed to be covered by the commodity position "Copper foil on plastic or paper". In 1996 and 1997 the net import of these foils was 720 and 1,370 tonnes, respectively.

Based on information from producers of printed circuit boards it is estimated that 90% of the production of printed circuit boards is based on FR4 (or similar) laminates, whereas the remaining 10% includes flexible prints and FR2 prints.

FR4 laminates contain approximately 15-17% TBBPA /32,33/.

FR2 laminates produced in Europe have traditionally contained approximately 4% TBBPA /32/, but halogen-free laminates have been on the market for more than a year. It has not been possible to discover the market-share of the halogen-free FR2 boards.

No information on an average content of BFRs in flexible laminates has been available, but the total turnover is estimated to be relatively small, and the BFRs in flexible laminates will not be included in the estimate.

Under the assumption that FR4 laminates account for 90% of the consumption and that TBBPA containing FR2 laminates account for 5% of the consumption, it is estimated that 100-160 tonnes TBBPA was used for production of printed circuit boards in Denmark in 1997.

2.1.5    Emission from Production Processes in Denmark

No actual data on emission of brominated flame retardants from plastic processing in Denmark are available.

Emission of brominated flame retardants from European plastic processing industry have been included in a study on industrial emissions of BFRs carried out for the European Commission in1995 /70/. It is in the study concluded that the information from the plastic processing industry was not sufficient to make any factual comments on the amount of BFRs released to the environment.

In the lack of data, emissions will be roughly estimated using loss-factors from ‘Use Category Document. Plastic Additives’ /25/. The document provides process specific loss factors for plastic additives. The loss factors are meant to be used in the absence of actual data.

Compounding   

Initially some emissions will be to the atmosphere, but ultimately all particles will be removed or settled and losses will be to solid waste or waste water. The loss factors are dependent on the particle size. For powders of particle size <40 µm the worst case loss factor is 0.05%; for particle size >40 µm the factor is 0.01%. There is an additional loss factor for organic flame retardants of 0.002%.

It will here be assumed that the loss predominantly is to solid waste with a worst case loss factor of 0.052%. For a rough estimate, the total import of BFRs as chemicals is multiplied by this factor, giving a total loss of <0,02 tonnes. The particles are assumed mainly to be disposed of with solid waste.

Conversion

Initial losses from conversion processes will be to the atmosphere. Subsequent condensation could result in losses to liquid waste. It will roughly be assumed that half of the losses is discharged to waste water.

The volatility is in the document taken to be similar to that of the least volatile plasticiser and antioxidant groups. The losses are dependent on the process.

On the basis of volatile losses the loss factors for worst case conditions are as follows:

Open processes:    

For processing significantly in excess of 200° C or for smaller processing sites (< 750 tonnes plastic per year) loss factors should be multiplied by a factor of 10.

Closed processes include conversion of thermosetting resins, extrusion and moulding processes. Open processes include thermoforming, calendering and fibre reinforced plastic fabrication.

For a rough estimate it is assumed that all processes based on compounds are closed processes, whereas the plastic semi-manufactures are processed in open processes. The loss factors are multiplied by a factor of ten for a worst case estimate.

Using the highest estimate for the use of plastic raw material and semi-manufactures in Denmark (see sections 2.1.2 and 2.1.3), the total emission can be estimated at <0.04 tonnes in 1997. Half of this is roughly assumed to be emitted to the air; half to waste water.

The estimate is a worst case estimate; the actual emissions may be much lower.

2.1.6  Summary

Brominated flame retardants are not produced in Denmark.

The total import with semi-manufactures for production in Denmark is summarised in table 2.3. The account gives the turn over of brominated flame retardant for compounding (chemicals), extruding and moulding (plastic compounds and masterbatchs), vacuum forming (other plastic semi-manufactures) and production of printed circuit boards.

Table 2.3
Import of brominated flame retardants with chemicals and semi-manufactures for production in Denmark

The consumption of brominated flame retardants with chemicals and compounds only gives a limited information about the consumption of BFRs with manufactured goods, as most end products are exported. This is illustrated by the fact that the consumption with chemicals and compounds in Sweden is very different from the Danish volumes. In Sweden with a population twice of the Danish population, a total of 560 tonnes TBBPA per year was used as chemicals in 1992/93 for compounding and plastic production /31/. Most of this was used for production of laminates for printed circuit boards - a production not present in Denmark.

Brominated flame retardants used for production processes in Denmark are summarised in table 2.4. Physical/chemical properties of the compounds are shown in appendix 3.

Table 2.4
Brominated flame retardants used in production processes in Denmark 1997