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Deca-BDE and Alternatives in Electrical and Electronic Equipment

3 Substitutes to Deca-BDE by application

• 3.1 Overview of substitution approaches
• 3.2 Substitutes for Deca-BDE in housings/enclosures
  • 3.2.1 Enclosures of HIPS
  • 3.2.2 Enclosures of ABS
  • 3.2.3 Enclosures of copolymers
  • 3.2.4 Summary of substitutes for enclosures and price
    comparison
• 3.3 Connectors, circuit breakers, etc.
  • 3.3.1 Parts made of thermoplastic polyesters
  • 3.3.2 Parts made of polyamide
• 3.4 Substitutes to Deca-BDE in cables, sheets and films made of PP
  and PE

3.1 Overview of substitution approaches

Substitution of Deca-BDE in a given polymer application can basically take place at three levels:

1.         Deca-BDE can be replaced by another flame retardant with adequate properties without changing the resin.

2.         The plastic material, i.e. the resin with flame retardants and other additives, can be replaced by another plastic material (incl. copolymers) with adequate properties.

3.         The need for flame retardants can be eliminated by design changes, or the entire product can be replaced by a different product with adequate performance.

An example of the latter type of substitution in EEE could be a solution where a reduction of the risk of flame propagating is achieved using a metal sheet to cover the plastic in contacts with current-carrying parts. Although level-3 substitution may be feasible for some applications, this study has focused on level-1 and -2 substitutions.

“Adequate properties” means that a plastic part manufactured from an alternative plastic material can meet the same fire-safety standards as the Deca-BDE application, and that the technical specifications of the part are also acceptable for the application.

Often, when seeking a substitute for undesirable substances, it is not possible to find one substance that has similar technical properties and can substitute for the undesirable substance in all of its applications. Such an alternative would, unfortunately, very likely also share the undesirable properties.

For this reason it may be necessary to search for different alternatives for different applications. In this study an “alternative” is defined as a flame retardant that can substitute for Deca-BDE for a specific application.

The application spectrum of Deca-BDE and selected brominated FR alternatives in EEE, according to Albemarle, is shown in Table 3.1. The application of Deca-BDE in foams, textiles and coatings is not shown, as they are not within the scope of this study. Other manufacturers may identify other applications of Deca-BDE, e.g. in wire and cables made of PP.

As indicated in the table, the flame retardant ethane-1,2-bis(pentabromophenyl) has the same application spectrum as Deca-BDE for the relevant polymers, while the application spectrum for ethylene bis(tetrabromophthalimide) differs with respect to a few base polymers. It should be noted that the table indicates only whether or not these FR substances can be used in the different plastics, and does not imply that the different FR substances have similar properties in the plastics.

Table 3.1 Application spectrum of Deca-BDE and selected brominated FR alternatives in EEE, according to Albemarle Product Selector [[21]]

	SAYTEX
Application	102E	8010	BT-93 BT-93W	120	CP-2000
Solid thermoplastics
ABS	•	•	•	•	•
HIPS	•	•	•	•	•
Nylon	•	•		•
Thermoplastic polyester	•	•	•	•
Polycarbonate	•	•	•	•
Polypropylene	•	•	•	•
Polyethylene	•	•	•	•
SAN	•	•
Alloys (PC/ABS, HIPS/PPO)	•	•	•	•
Thermoplastic elastomers	•	•	•
Wire and cable
Silicone	•	•	•	•
PVC	•	•
EPDM	•	•	•	•
Thermosets
Epoxy	•	•	•
Phenolic	•	•	•		•
Unsaturated polyester	•	•	•
Vinyl esters	•	•	•

102E:                        Deca-BDE BT-93;
BT-93/BT-93W:        Ethylene bis(tetrabromophthalimide)
8010:                        Ethane-1,2-bis(pentabromophenyl)
120:                         Tetradecabromodiphenoxybenzene
CP-2000:                                TBBPA
l: used additively ; ¢: Used reactively

3.2 Substitutes for Deca-BDE in housings/enclosures

Globally, the sources cited previously confirm that the major application of Deca-BDE appears to be in flame retarded HIPS used for housings/enclosures of electronic equipment.

Table 3.2 shows the percentage of enclosures of different types of electronic equipment made from different resins, as presented by Tony Kingsbury, Chairman, American Plastics Council E&E Work Group, at the BFR Roundtable, September 2002. The figures present the situation in the US around 2002, which, at least with regard to TV-sets, is different from the situation in Europe. Similar data for the European market have not been identified.

Ignition resistant (i.e., flame retarded) HIPS is widely used for enclosures of TV-sets in the US, whereas personal computer monitors are mainly made from ABS and PC/ABS because these resins have higher impact strength and are less susceptible to cracking [12]. According to the US data, HIPS is also used for a significant percentage of the enclosures of printers, fax machines and scanners, but without flame retardants. This seems not to be the case in the European market. Both Danish [7] and German [[22]] studies have reported the use of flame retardants in enclosures of printers, especially laser printers.

Table 3.2 Resins used in electronic enclosures in the USA [[23]]

Note: IR = ignition resistant = flame retarded

According to Lowell (2005), HIPS for TV-sets accounts for the major part of Deca-BDE use in the USA: "Roughly 80% of deca-BDE use in the U.S. is thought to be in electronic enclosures, with the vast majority used in the back and front plates of television sets." [12] "DecaBDE is used in TV enclosures because it is an inexpensive, highly efficient flame retardant that is very compatible with inexpensive high impact polystyrene (HIPS). In a TV enclosure, the back plastic panel and in some cases the front panel will be made from decaBDE HIPS containing roughly 12% decaBDE by weight in combination with antimony trioxide (ATO) at a ratio of roughly three parts decaBDE to one part ATO."[12]

In accordance with this U.S. reference, Great Lakes Corp. wrote in 2006: "TV housings are the largest use of decabromodiphenyl oxide (Great Lakes DE-83R™) as a flame retardant in HIPS." [[24]]

In Europe, the application pattern as concerns TV-sets is quite different. According to a market report on the European flame retardant chemicals industry in 1998: "The market for brominated flame retardants in HIPS resins has largely collapsed, due to relaxed requirements for television sets in Europe and environmental concerns. Outside of Germany, the Netherlands and the Nordic countries there is limited use of decabromodiphenyl oxide, at about 10-12%, and perhaps also octabromodiphenyl oxide and decabromodiphenyl." [[25]] Note: "decabromodiphenyl" should probably read "decabromobiphenyl".

The difference in the use of Deca-BDE for HIPS between Europe and the USA, as mentioned above, has mainly been driven by differences in flame retardancy requirements and environmental concerns.

In the USA, UL 94 V-0 grade FR, which greatly limits the risk of external ignition by an open flame, is required by UL 1410 for TV-set back plates. In Europe, TV-set back plates have to comply with the EN/IEC 60065 standard, in which the aim is to prevent ignition of the TV-set by inner sources of ignition. The European standard allows major plastic parts of TV-set back plates and housings to be made from materials that fulfil the requirements of the less demanding UL 94-HB (horizontal burn test) standard [32], provided that design measures are taken to adequately isolate flammable materials from potential internal ignition sources.

According to investigations by Stiftung Warentest in Germany, the share of (new) TV-set housings with halogenated FR dropped from 60-70% in 1993/1994 to approximately 25% in 1995 and under 10% in 1996/1997. By the end of the 1990s, the European manufacturers of TV-sets had mostly renounced FRs in favour of structural solutions, and used plastics that achieved the UL 94 HB standard [26;44]. This is still the case for some European manufacturers.

However, in response to fire statistics indicating that the number of TV-set fires in Europe in the late 1990's was an order of magnitude higher than the number in the USA [[26]], an extensive discussion of the relevance of external sources of ignition (e.g. a burning candle) took place, and there has been a partial revival of the use of FR polymers for TV-set housings, especially among international “brand name” European manufacturers. Panasonic, Philips, Sony and Finlux, in November 2004, signed a commitment to voluntarily meet the higher fire safety classification V-1 (or equivalent) for all of their CRT models as of 1st January 2006 [[27]] [[28]].

Today a significant percentage of CRT-TV housings sold on the European market are still made from HIPS without FR, but the major European manufacturers of TV-sets now seem to be using copolymers like PC/ABS, PS/PPE or PPE/HIPS either without FRs, or with non-halogenated FRs (details in section 3.2.4).

Meanwhile, CRT TV screens are in the process of being replaced by flat panel TV-sets (FPTV) with LCD panels or plasma display panels. General Electric [[29]] calculated the global plastic consumption for FPTV-sets in 2005 at approximately 42% PC/ABS, 33% HIPS, 14% FR-HIPS, 10% modified PPE and 1% other. The weight of the enclosures and materials used are virtually the same as in CRT TV-sets, and the discussion regarding TV-set enclosures applies as well to flat panel TV-sets, as discussed further in section 3.2.4.

For office equipment, American and European standards have essentially the same flammability requirements, with minor differences. According to EN/EIC 69950, applied in Europe, enclosures of moveable office machines (<18 kg weight) have to comply with UL 94 V-1, whereas enclosures of stationary and larger movable office machines (>18 kg weight) have to comply with UL 94 V-5.

In effect, a range of resins can be used for enclosures of TV-sets, office equipment and other electronic equipment. Deca-BDE and octa-BDE, in particular, have been used over the years to obtain FR HIPS and FR ABS, respectively.

Alternative solutions that have been used by industry include either replacing Deca-BDE in HIPS or ABS with another flame retardant, or using other copolymer resins in which the same level of flame retardancy can be achieved by using other BFRs or halogen-free FRs.

3.2.1 Enclosures of HIPS

As mentioned, Deca-BDE is widely used for enclosures made of HIPS. Deca-BDE is the cheapest FR for V-0 grade HIPS, but has some technical disadvantages for some applications (see below). The selection of the most suitable flame retardant depends heavily on the requirements of the final application, and the price/loading of the flame retardant.

A number of flame retardants are marketed for use in HIPS. Table 3.3 lists eight commercially available flame retardants that may be used to achieve V-0 HIPS besides Deca-BDE, and indicates the section of this report in which further characteristics of the substances can be found.

Table 3.3 Examples of commercially available flame retardants for V-0 grade HIPS

*      Data on the product from Albemarle only. The data are provided by SpecialChem S.A., an Internet-based knowledge and solution provider in the domain of specialty chemicals, with direct reference to Albemarle.

**    The class of substances is included in a list summarised March 2006 by J. Troitzsch [[31]], editor of the Plastics Flammability Handbook [[32]]. The substance group was not assessed further.

***  The low loadings indicate that the "styrenic based resins" may be styrenic based copolymers.

n.a. Not assessed.

In Table 3.4 the properties of Deca-BDE in HIPS are compared to a few of the recommended substitutes that have an application spectrum close to that of Deca-BDE. As indicated in the table, based on information from Albemarle Corp., Deca-BDE (102E) shows poorer performance as to bloom resistance, UV stability and physical properties in comparison with BFRs based on Ethylene bis(tetrabromophthalimide) (BT-93, BT-93W) and Ethane-1,2-bis(pentabromophenyl) (8010). It should also be noted that SAYTEX® BT-93 achieves UL 94 V-0 only at 1/8-inch polymer thickness, whereas SAYTEX® 8010 achieves the UL 94 V-0 rating at both 1/8-inch and 1/16-inch thickness [[33]].

Table 3.4 Comparison of Albemarle FRs recommended for HIPS (based on [[34]])

Notes:
+ + Very Good   + Good   – Fair   – – Poor

BT-93 and BT-93W: Ethylene bis(tetrabromophthalimide)
8010: Ethane-1,2-bis(pentabromophenyl)
102E: Deca-BDE

The term "WEEE complaint" probably means "RoHS compliant".

According to the table, Deca-BDE does not provide any of the listed technical properties that cannot be provided by the other flame retardants. As pointed out by Albemarle, "Flame retarded HIPS based on SAYTEX BT-93 or SAYTEX 8010 show an excellent balance of physical properties, UV stability, lower formulation cost and result in thermally stable, easily recyclable, non-blooming formulations. This allows FR HIPS compounds currently based on other flame retardants to be replaced as well as substituting FR HIPS based on Saytex BT93 and S8010 for other resins, like FR ABS and FR PC/ABS." [34]

Also according to Albemarle Corp: "Saytex 8010 is the most cost effective non-decabromodiphenyl-oxide (DECA) flame retardant for HIPS." [85]

The technical disadvantages of Deca-BDE are also addressed by the Dead Sea Bromine Group in a paper in Plastics Additives & Compounding, April 2001: "Existing flame retardant products for these applications seldom meet all of the required properties. Decabromodiphenyl oxide (Deca) is cost efficient in HIPS but has poor UV stability and is not melt blendable during injection moulding." [[35]] And further: "In both HIPS and ABS, FR-245 is cost efficient and offers an excellent combination of melt flow, impact and light stability properties." [35] FR-245 consists of Tris(tribromophenyl) cyanurate; see section 5.12.

The main advantage of Deca-BDE is its price. Prices of HIPS compounds with different flame retardant systems are discussed further in section 3.2.4.

Another advantage of Deca-BDE that has been emphasised is that plastics containing Deca-BDE can be recycled several times while maintaining their flame retardant properties. However, there is some concern that the recycling of Deca-BDE HIPS may promote the formation of polybrominated dibenzodioxins (PBDDs) and polybrominated dibenzofurans (PBDFs).

The suitability of an FR plastic for recycling is a property shared with several of the potential FR substitutes, as indicated by Albemarle Corp.: "The results of the recycling study show that HIPS/S-8010 and HIPS/BT-93 are not only easily recyclable, but were also found to meet the requirements of the German Dioxin Ordinance." [[36]] And further, in another paper: "The V-0 HIPS resin with EBP was also analyzed for the polybrominated dibenzofurans and dibenzodioxins after five injection molding cycles (Table III). Even after recycling no detectable level of these species was found, and the recycled V-0 FR HIPS easily conforms to the specified maximum allowable quantities of the German Hazardous Substances Ordinance." [[37]]

It has not been possible to identify any commercially available halogen-free flame retardants that can achieve V-0 grade HIPS or ABS. Manufacturers of EEE who demand enclosures without brominated flame retardants can usually replace HIPS with a copolymer of PPE/HIPS or PC/ABS, as further discussed in section 3.2.3.

3.2.2 Enclosures of ABS

Traditionally Octa-BDE, rather than Deca-BDE, has been the flame retardant of choice for ABS. The OECD monograph from 1994 on selected brominated flame retardants states, concerning octa-BDE: "The bulk of its applications are for compounds based on acrylonitrile butadiene styrene (ABS), where this brominated chemical offers the comparative advantage in terms of melting range and colour." [17] ABS is not included in the OECD monograph's list of Deca-BDE applications, or the list of Deca-BDE applications mentioned by BSEF, referred in Table 2.3.

Deca-BDE may, to some extent, have replaced Octa-BDE after the EU ban on Octa-BDE, and ABS is mentioned by the European Brominated Flame Retardant Industry Panel (EBFRIP) in the panel's comment to the European Commission's Stakeholder Consultation: "Alternatives are not always available: In certain plastic resins like HIPS, ABS, and PBT, there are currently no cost-effective alternative flame retardants which can provide good flame retardancy and good mechanical properties." [19]

However, marketing materials recommend other brominated flame retardants than Deca-BDE as alternatives to Octa-BDE in ABS. Great Lakes Corp. wrote in the pamphlet, "Flame Retardant Alternatives to Octa-PBDE in ABS:" "The recommended alternatives to octa-PBDE in ABS are Firemaster® FF-680 and Great Lakes BA-59P^TM." [93] These alternatives are based on bis(tribromophenoxy)ethane and TBBPA, respectively. Deca-BDE is not mentioned in the pamphlet.

The Risk Reduction Strategy for Octabromodiphenyl Ether prepared for the UK Department for Environment, Food and Rural Affairs (DEFRA) listed the following alternatives to Octa-BDE in ABS, in cases where the polymer itself was not substituted: TBBPA, ethane 1,2-bis (pentabromophenyl) and bis(tribromophenoxy) ethane [[38]]. Again, Deca-BDE was not mentioned as a FR of any importance for use with ABS.

A number of flame retardants are marketed for use in ABS. Table 3.5 lists, in addition to Deca-BDE, six commercially available flame retardants that can be used to achieve V-0 ABS.

Table 3.5 Examples of commercially available flame retardants for V-0 grade ABS

*      As Deca-BDE traditionally has not been used for ABS, no technical data on the Deca-BDE loading has been identified. The Deca-BDE loading may be assumed to be slightly lower than the octa-BDE loading of 16% [93]

**    Data on the product from Great Lakes Corp. only.

***  The substances are included in a list summarised March 2006 by J. Troitzsch [31]. The loadings of the substance have not been assessed further.

n.a. Not assessed.

Other manufacturers mention the use of TBBPA as well in ABS. ICL Industrial Products states in the data sheet for FR-1524 (TBBPA): "It is also cost-effective as an additive flame retardant in applications such as ABS.…" [98]

The Dead Sea Bromine Group wrote in a paper published in Plastics Additives & Compounding, April 2001: "Tetrabromobisphenol A (TBBA) is cost efficient and melt blendable in ABS but has low thermal stability, poor impact properties and may not meet UV stability standards. Moreover, it lowers heat distortion temperature." [35] And further: "In both HIPS and ABS, FR-245 is cost efficient and offers an excellent combination of melt flow, impact and light stability properties." [35] FR-245 is the company’s trade name for tris(tribromophenyl triazine.

The cost considerations for replacing Deca-BDE in ABS are quite comparable to the considerations regarding the replacement of octa-BDE. The above-mentioned Risk Reduction Strategy for octa-BDE, produced by DEFRA, includes a detailed assessment of the cost of substituting octa-BDE in ABS. The cost estimate was prepared for the substitution of 1,2-bis(pentabromophenyl) ethane for octa-BDE in ABS, which, according to the assessment, represented the greatest cost increase of any of the substitutes. The increase in polymer price with the substitute flame retardant was estimated at 25%. (The price of octa-BDE was estimated at 3.6 €/kg, and the price of ABS flame retarded with 15% octa-BDE was 1.4 €/kg. All figures are assumed to be based on 2002 prices). The increase using TBBPA as a substitute would be lower. Furthermore, the cost estimate included an estimate for research and development (R&D) by companies using octa-BDE. The total research and development costs for UK manufacturers were estimated at 0.5 m€, while the cost due to the increased price of flame retardants was estimated at 1.2 m€/year. To this was added the costs of replacing moulds: "Costs of new moulds, depending upon the size and complexity of the product have been estimated at £50-100,000 (€80-160,000). The British Plastics Federation has indicated that a typical SME in ABS processing would have around 15 to 20 moulds." [38] The total costs of replacing moulds, including the cost of downtime for polymer processing companies, were estimated at 4.8 m€

If the increased costs are passed on to the consumer, the increase in the average price of products would be less than 1%: "Thus, the total estimated costs to industry, taking into account the likely increased cost of substitutes and the potential need to replace moulds is around €7.5 to €12 million over five years. If these increased costs were passed on to the consumer, the percentage increase in the average price of products would be between 0.19% and 0.30%, taking into account an estimated 3 million products on the market per year". [38]

The price of Deca-BDE may be slightly lower than the price of octa-BDE, and consequently, the price difference between Deca-BDE and alternatives may be slightly higher. Further, it should be noted that the "average" price increase of products referenced above would be significantly lower than the price increase of those products that include large parts made of ABS, e.g. TV-sets with ABS enclosures. This is further discussed in section 3.2.4.

3.2.3 Enclosures of copolymers

PPE/HIPS and PC/ABS copolymer blends have been marketed by a number of resin suppliers as substitutes for brominated HIPS and ABS resins. As mentioned before, these copolymers are also used for more demanding applications, e.g. in information technology (IT) equipment.

PPE refers to polyphenylene ether homopolymer or copolymer. The polymer may also be designated polyphenylene oxide (PPO) and the copolymer PPO/HIPS or PPO/PS. The addition of 17 to 20 percent PPE by weight enhances the HIPS charring ability and therefore improves flame retardancy [12]. From a processing standpoint, PPE/HIPS blends have very similar flow properties to HIPS. Flow properties are important in the injection moulding process, as resin substitutes with similar flow properties to HIPS mean similar opportunities for the design of products with fine structural parts, and fewer changes to the expensive tooling and moulds used in the moulding process.

PC/ABS and PC polymers typically contain a very small amount of fluoropolymer (roughly 0.3%) for drip resistance, so the polymers are consequently not 100% halogen-free [12].

A number of both halogen and non-halogen flame retardants are marketed for use in HIPS/PPO and PC/ABS copolymers. Table 3.5 lists, besides Deca-BDE, seven commercially available flame retardants for V-0 PC/ABS or PPE/HIPS. In practice, European manufacturers of TV-sets, as mentioned in section 3.2, usually use V-1 grade or lower.

Halogen-free V-0 and V-1 grades are both available from a number of compound suppliers. As an example, halogen-free V-0 grade PC/ABS is marketed by Bayer (Bayblend®) [[39]] and RTP Company (RTP 2500 FR-110) [[40]]. Halogen-free V-0 grade PS/PPE is marketed by GE Plastics (NORYL® LS175) [[41]], and V-0 grade halogen-free PPO/HIPS is available from Total Petrochemicals (FT-878) [[42]].

According to the Kingsbury 2002 reference, RDP is the dominant FR in PC/ABS and PPO/PS on the American market, while the use of BDP is growing, and the use of TPP is shrinking [23].

Albemarle Corp. has written about NcendX (based on BDP): "PC/ABS and PPO/HIPS blends are the material of choice for higher end electronic enclosures. NcendX® P-30 liquid phosphorus flame retardant is an outstanding performer in PC/ABS and PPO/HIPS blends. It actually improves resin melt flow and exhibits outstanding thermal stability, excellent hydrolytic stability, low migration and low volatility" [119]

HIPS/PPO with halogen-free FRs may not match all properties of HIPS with BFR, as pointed out by Great Lakes regarding the UV stability of the blend: "Where a non-halogen flame retardant is required, HIPS requires another polymer such as PPO to achieve the UL-94 V-O flammability requirement. The addition of this polymer dramatically changes the processing conditions for injection molding as well as resulting in higher costs for this type of system, and in general cannot achieve the level of UV stability which can be reached with selected brominated fire retardant systems [[43]]

Table 3.6 Examples of commercially available flame retardants for V-0 grade PC/ABS and PPE/HIPS

*      Loading for V-0 grade PC/ABS [[44]]

**    The substances are included in a list summarised March 2006 by J. Troitzsch [31]. The loadings of the substance have not been assessed further.

n.a. Not assessed.

Examples of flame retardants in copolymers and their uses are shown in the following table taken from Lowell (2005) [12].

Table 3.7 Phosphate Flame Retardants Used in Electronic Enclosure Applications (cut from [12])

The price of the PPE/HIPS and PC/ABS copolymer blends is compared to HIPS with Deca-BDE in the next section.

3.2.4 Summary of substitutes for enclosures and price comparison

Deca-BDE may potentially be used in enclosures of a range of EE products like TV-sets, printers, photocopiers and hair dryers. For all identified applications of Deca-BDE in enclosures, alternatives without Deca-BDE are available.

The following section will focus primarily on TV-set enclosures (although CRT TV-sets are in the process of being phased out), because most information is available on this product group, and the results for TV-set enclosures can be applied to other product groups.

Polymers and flame retardants for TV-set enclosures
Whereas HIPS with Deca-BDE seems to be the material of choice for TV-set enclosures in the USA, major European producers of TV-sets today use HIPS without FR, or copolymers with non-halogenated flame retardants.

A number of products in the lower price segment of the market still use HIPS without flame retardants, which meets the current standard (UL 94 HB). An example of HIPS without flame retardants advertised for use for TV-set enclosures is BASF's Polystyrol 496 F [[45]].

Table 3.8 summarises information on resins and FRs used by five important producers of TV-sets for the European market. Although the major producers have returned to V-1 or V-0 grade housings, they have not returned to Deca-BDE.

Table 3.8 Resins and FRs used by five important producers of TV-sets for the European market

According to Lowell (2005) [12], roughly 20,000 tonnes of resorcinol bis(diphenyl phosphate) (RDP) are used annually for the European TV market, but this figure has not been confirmed in this study.

Costs for Deca-BDE substitution in TV-set enclosures
As described for ABS in section 3.2.2, the cost of substitution is dependent on the difference in price of the raw materials, research and development costs, and possible changes of moulds and other tools. The costs of changes in moulds, if necessary, may be a significant part of the total costs.

The raw material costs for plastic enclosures depend on a number of factors, including the cost of the resin itself, the cost of the flame retardant and any volume pricing adjustments. The raw material costs frequently differ from region to region (e.g. Europe vs. USA or Asia), depending on regional market conditions.

The one-time costs of mould changes depend heavily on the timing. With a longer transition period, the costs can be lowered by introducing substitutes when the moulds are changed along with periodic design changes. As described by AEA Technology Environment (1999) [51], the time scale of changes in basic elements of a TV-set, like the chassis, may be longer than the time scale for changes in models. A TV model is typically produced for only about a year, but may be on sale for 2-3 years. Although a specific TV model has a relatively brief market life, manufacturers utilise some basic building blocks like the chassis, the heart of a TV-set, for a longer period of time. The chassis may have a useful life of 5-7 years. The new model TVs produced each year are derivatives of the original chassis, with minor electronic enhancements, as well as different cosmetic designs; no manufacturer completely redesigns its product range over a mere 1-2 year period [[51]]. The typical time scale for changes in enclosures is not assessed in this study.

It is beyond the scope of the present study to undertake a detailed assessment of all costs related to the substitution of Deca-BDE in enclosures, but in the following, the incremental costs of plastic raw materials are briefly discussed.

The price of plastic raw materials depends on product quality, purchased volumes, market conditions, etc. In Table 3.9, indicative price levels of HIPS with different flame retardants (information from Total Petrochemicals) is shown. Total Petrochemicals, with a market of about 30,000-40,000 tonnes HIPS and HIPS/PPE for TV-set enclosures in Europe, supplies not only standard HIPS but also HIPS with brominated FR and halogen-free FR [[52]] (the precise FRs used are proprietary). HIPS with Deca-BDE is only marketed by Total Petrochemicals in Southeast Asia, and the indicated price consequently reflects this market. It should be noted that Total Petrochemicals maintains a strategy of being a high quality supplier of HIPS and compounds, and therefore the prices shown in the table will not necessarily be the lowest on the market.

For the following paragraph, average prices in table 3.9 is applied. Using average prices, for the brominated alternatives, the price about 109% (for V-1 grade) and 121% (for V-0 grade) of the price of HIPS with Deca-BDE. The extra cost corresponds to approximately 0.15 €/kg to 0.35 €/kg. Similar price increases for V-0 grade HIPS have been reported by Panasonic when replacing Deca-BDE with other BFRs in their TV-sets in the USA [53]. The price of the halogen-free HIPS/PPE is approximately 158% of Deca-BDE HIPS, corresponding to a cost increase of 0.95 €/kg. Total Petrochemicals does not market PC/ABS, but estimates the price of competitive products to be 2.60 – 2.80 €/kg (spring 2006). The price of PC/ABS has decreased since 2005, due to lower PC raw material costs. This means that the price of PC/ABS is about 164% that of Deca-BDE HIPS, corresponding to a cost increase of 1.05 €/kg.

These prices reflect the experiences of only one major compounder, but indicate the order of magnitude of price differences between compounds with Deca-BDE and alternatives.

To put these prices in perspective, the extra raw material cost of the full enclosure of an average TV-set (front and rear enclosure) may be estimated. Lowell (2005) has estimated the weight of the front and rear enclosure of an average 27.5-inch TV-set to be 5.45 kg [12]. Using the prices of compounds from Total Petrochemicals, the extra cost of using the alternative materials PPE/HIPS or PC/ABS would be about 5-6 €. The extra cost of using other BFRs would be 0.8-1.9 €, depending on the flammability grade. Note that these estimated costs are for the raw materials only. If the total production cost of a 27.5-inch TV-set, according to information obtained from Panasonic [[53]], is roughly 300 €, then the extra material cost of these alternatives can consequently be estimated at 0.5-2% of the production cost, with the higher part of that range applicable to the halogen-free HIPS/PPE.

Table 3.9 Indicative price levels of HIPS compounds (information from Total Petrochemicals), spring 2006 [[54]]

CRT-based TV-sets are soon to be relegated to history, but the cost estimates above can quite well be applied to new LCD panel TV-sets. In the US, the back cover of the LCD panel TV-set has to comply with UL 94 V-0, whereas European standards have less strict requirements. In the USA, the weight of the back cover of an average LCD panel TV-set (50-inches) is about 4 kg [53].

As discussed previously, the costs of moulds and other tools may be significant, but can be greatly reduced if new materials are introduced concurrently with new designs/products. The extra material costs of some 5 € for a new TV-set is, of course, more critical for a product in the low price market segment, competing above all on retail price, than it is for a product in the high end of the market, competing on technical features, environmental profile, etc.

Cost calculations in other studies
The costs associated with the replacement of octa-BDE and Deca-BDE by other flame retardants have been discussed in a few other studies.

In Lowell (2005) [12] the incremental material cost for an average 27.5-inch CRT TV-set, with a front and rear enclosure weight of 3.5 kg and 1.95 kg respectively, is estimated. The result is shown in Table 3.10. The price of the HIPS with Deca-BDE material is nearly the same as shown in Table 3.9, whereas the prices of HIPS/PPE and PC/ABS are significantly higher, which may reflect actual differences between the European and American markets, including a greater European demand for copolymers with non-halogenated FRs.

It should be noted that the figures are estimates only, and that thin-walling and volume related pricing are not factored into the calculations, nor are other cost increases or decreases due to changes in energy use, yield, or cycle time. The Lowell (2005) study estimated that the extra cost of raw materials corresponded to an increase of 1.5 to 2.5% of the total price of the TV-set.

Table 3.10 Prices of various V-0 systems for enclosures on the American market in 2004 (based on Lowell, 2005 [12])

*              All prices by the truckload except HIPS (railcar). Converted here from $/lb using 1 $ = 0.824 €; 1 lb =0.454 kg.

**            "Average" TV-set is a 27.5-inch CRT unit with front and rear enclosure weights of 3.5 and 1.95 kg, respectively.

***          HIPS with Deca-BDE

As discussed in section 3.2.2, the assessment prepared for the UK Department for Environment, Food and Rural Affairs (DEFRA) included an estimate of the cost of replacing octa-BDE in ABS enclosures. The cost of replacing Deca-BDE in similar enclosures can be assumed to be comparable, although probably slightly higher. In the assessment it is estimated that, if the increased cost were passed on to the consumer, the percentage increase in the average product price would be between 0.19% and 0.30%, assuming an estimated 3 million products on the market per year [38]. The DEFRA study does not include a separate cost assessment for TV-sets or other products in which the FR plastic part accounts for a large part of the product.

As part of the development of the Washington State Polybrominated Diphenyl Ether (PBDE) Chemical Action Plan, the additional cost of substituting Deca-BDE was assessed as well. It should be noted that the estimate reflects the US market, where Deca-BDE HIPS has dominated the market for TV-set enclosures. In the Action Plan it was concluded:

"A wide range of values have been reported regarding what the final price increase would be. The Lowell report estimates the materials-based cost shift between 1.5 percent and 2.5 percent of the final product prices for televisions, although it may not fully cover the costs. Personal conversations with four manufacturers of finished products currently making deca-BDE-free products estimated the increase at between 5 and 15 percent. Another company indicated a price increase of less than 0.5%. Ecology finally estimated the cost increase between 5 to 15 percent for the final product (finished products and components of finished products). This is despite the fact that the plastic itself may increase in price by more than 50 percent and despite the fact that the price of the alternative itself may be doubled. However, some manufacturers say the material is not the only basis for the cost shift, and cite greater energy, down time and form retooling. Thus there is a difference between the expected cost shift and the expected price shift, although there may be no difference between the expected cost shift and a diminishment of the expected price reduction. The latter is very difficult to quantify from market data." [[55]]

3.3 Connectors, circuit breakers, etc.

As indicated in Table 2.3, small inner parts of electrical and electronic equipment like connectors, circuit breakers, etc. made of PBT or polyamide (PA) are among the main application areas of Deca-BDE.

According to a presentation by Munro et al., of Great Lakes Chemical Corp., at ADDCON 2004, electrical internals account for 27% of the total global consumption of FR polymers [56]. Of this total, PBT accounts for 28%, PET for 10%, PA for 31%, PC/PPS for 15% and other polymers for 16%.

PBT is one type of thermoplastic polyester and, together with PET, is often designated as a "thermoplastic polyester" or - as in some of the quotations below - simply a "polyester," where "thermoplastic" is implicitly understood from the context.

Polyamide is also known as “PA” or “nylon.” Different types of PA may require different flame retardants. Common types are PA6 and PA66. Deca-BDE is, for thermal reasons, generally only used in PA6.

Circuit breakers, connectors, etc. are typically in contact with current-bearing parts of EEE, and therefore the FR requirement is usually V-0 grade.

Flame retarded thermoplastic polyesters and PA are today mainly based on brominated FR technology, as presented by Munro et al.: "The majority of flame retardant polyester and polyamide compounds used in the electrical and electronic market segment are based on brominated flame retardant technology. There are a wide variety of brominated flame retardants that are used in both resins which all give different performance advantages with increasing costs for the superior technical performance." [56]

The global flame retardant additive consumption in thermoplastic polyesters and polyamide, based on a presentation by Great Lakes Corp. in 2004, is shown in Table 3.11.

Table 3.11 Global flame retardant additive consumption in polyesters and polyamides in EEE (based on [[56]])

*      Assumed to be tetrabromobisphenol-A carbonate oligomer.

Deca-BDE represents about 10% of the FR consumption for thermoplastic polyesters, corresponding to 1,500 tonnes, and 6% of the FR consumption for polyamides, corresponding to 840 tonnes globally. Considering the global consumption of Deca-BDE in 2003 to be 56,418 tonnes [18], it may be estimated that Deca-BDE consumption for polyesters and polyamide in electrical internals represents about 2.7% and 1.5%, respectively, of total Deca-BDE consumption.

The significant difference between these percentages and the data from the early 1990's, when thermoplastic polyesters and polyamide were reported to account for 20% and 15%, respectively, of global Deca-BDE consumption, may be an indication of the gradual replacement of Deca-BDE by other BFRs.

The figures for the entire market (not only for EEE as in table 3.11) for flame retarded polyamide in Western Europe in 1998 show a significantly different pattern, with non-halogen FRs accounting for 42% of the total (Table 3.12). To what extent this difference reflects differences between the Western European market and other markets, or reflects the fact that non-halogen FRs have a higher market share of FRs for non-EEE applications in Western Europe, has not been investigated.

Table 3.12 Western European market for flame retardants for all applications of PBT/PET and PA in 1998, according to IAL Consultants’ Market Report [25]

* used as synergist with halogenated flame retardants

The advantage of Deca-BDE for these applications is its low cost, whereas other BFRs provide superior mechanical properties as stated by Munro et al.: "As a general rule the monomeric additives are lower cost solutions but tend to suffer in terms of compatibility and mechanical properties. These include additives such as decabromodiphenyl oxide and decabromodiphenyl ethane. The polymeric solution such as brominated epoxies, carbonates and styrenes give superior mechanical properties and compatibility over the monomeric systems. The ability to change the molecular weight of the polymeric systems can be used to give different flow performance while changing the monomers and copolymer components can lead to improved compatibility and high temperature performance." [56] Note: Decabromodiphenyl oxide is synonymous for Deca-BDE.

According to the paper, non-halogenated flame retardants accounted globally for only 1% of the FR used in thermoplastic polyesters, and 15% of the FRs used in PA. The percentage in Europe may quite well be higher.

That Deca-BDE is not the principal FR choice for connectors is also indicated by the fact that Albemarle's Flame Retardants web-page for "Connectors" does not include Deca-BDE in the list of 9 flame retardants for use in connectors [102].

3.3.1 Parts made of thermoplastic polyesters

Thermoplastic polyesters, mainly PBT and PET, are employed in applications requiring high FR performance levels. Applications in EEE include plug-in connectors, connector strips, switching systems, housings for automatic overload protectors, capacitor pots, in coil formers, lamp parts, personal computer fans, power supply components, parts for electric drives, sheathing for waveguides and many other products [[57]].

The characteristics of PBT that are most difficult to substitute are high dimensional stability and low water absorption. Beside these characteristics, PBT has great stiffness and strength, high resistance to chemicals and heat distortion, good dielectric properties, and high gloss and surface hardness.

Until recently, only halogenated flame retardants have been able to provide FR PBT, and brominated flame retardants have accounted for nearly 100% of this market.

The main properties of Albemarle Corp's flame retardants for PBT, according to SpecialChem S.A (with explicit reference to Albemarle Corp.) are shown in Table 3.13.

As quoted in the previous section, a number of the other flame retardants have superior properties to Deca-BDE (102E in the table), which has a high rating only on "colour".

Table 3.13 Comparison of Albemarle FRs recommended for PBT [[58]]

Notes:
+ + Very Good   + Good   – Fair   – – Poor

HP-7010, PBT-620: Brominated polystyrene
BT-93; BT-93W:        Ethylene bis(tetrabromophthalimide)
120:                          Tetradecabromodiphenoxybenzene
8010:                        Ethane-1,2-bis(pentabromophenyl)
102E:                        Deca-BDE

A list of commercially available flame retardants for V-0 grade PBT/PET is shown in Table 3.14. For some of the flame retardants, relative formulation costs are indicated on the basis of information from Great Lakes Corp.[56], and the formulation costs can only be considered indicative for the commercial products from this company.

Recently, Clariant GmbH has developed a new class of halogen-free phosphorous based flame retardants, more specifically alkyl phosphinic acid salts marketed under the trade name Exolit® OP, which are effective flame retardants for engineering plastics like PA and PBT [[59]].

Polyester compounds using this flame retardant system are marketed exclusively by the compounder Ticona [[60]]. The new Celanex XFR range consists of four grades: one unreinforced and three reinforced with 10, 20 or 30 percent glass fibres. The compounds can meet UL 94 V-0 down to 0.8 mm material thickness. According to Ticona, four main features distinguish Celanex XFR from other phosphorous-containing flame retardant systems: high efficacy, thermal stability up to 300°C, virtual absence of migration and emissions, and problem-free coloration of the compounds. According to Ticona, Celanex XFR is suitable for use in 20% of the European PBT market [60].

Table 3.14 Examples of commercially available flame retardants for V-0 grade PBT

*1    Data on the product from Great Lakes Corp. only [56]. Formulation costs: 1=low; 5=high

**    Source: [58]. It is not specifically mentioned that the loading is for V-0 grade, but it is indicated that the FR efficiency of the substance is similar to that of Deca-BDE.

For the brominated alternatives used with PBT, as indicated in Table 3.14, ethane-1,2-bis(pentabromophenyl) and brominated epoxy polymer are the cheapest alternatives. As Deca-BDE represents only 10% of the market, it is evident that the higher price of the alternatives is outweighed by their superior technical properties.

It has not been possible to confirm from independent sources the relative price difference between PBT flame retarded with Deca-BDE, and PBT using the new halogen-free alternatives. According to the manufacturer, Clariant GmbH, in 2004, "Flame retarding polyamide or polyester with Exolit phosphinates will result in compounds which are (at current prices) comparable or only slightly more expensive than compounds with brominated flame retardants like PBDEs, brominated polystyrene or brominated benzacrylates. Phosphinates are more expensive on a per kg flame retardant basis, however, realistically the price per volume of flame retarded polymer compound should be compared. The necessary dosage of phosphinates is lower compared to brominated flame retardant systems which usually consist of the brominated flame retardant plus antimony trioxide as a synergist, i.e. phosphinates are more effective." [59]

In the next section, the price of V-0 grade, glass-fibre-reinforced PA, flame retarded with organic phosphinates, is compared to a similar PA, flame retarded with Deca-BDE. The incremental price of the PA with phosphinates is estimated at 27%, which may roughly indicate the order of magnitude of the price increase for PBT as well.

In 2004 the production capacity of FR phosphinates was limited to several thousand tons from Clariant GmbH, which is the only supplier [59].

Unlike the situation for enclosures, in which HIPS and ABS can be replaced by copolymers, the properties of the thermoplastic polyesters and polyamides cannot easily be obtained by use of other resins. Lassen et al. (1999) [7] discussed briefly the options for replacing FR PBT with other plastics: The constraint on replacing bromine-containing PBT with halogen-free polyamide is not the price, but the different technical properties of the two types of plastic. Other options would be to use resins that are inherently less flammable. Halogen-free polyketone could be a possible alternative, but is about 50% more expensive than PBT and polyamide, and this price difference could be a constraint to replacing, e.g. PBT/PET with this plastic. The price of high performance thermoplastics such as polysulfone, polyaryletherketone (PAEK) or polyethersulfone (PES) is significantly higher than the price of PBT and PA. In general terms, the price varies from 2x for polysulfone, to significantly more for the most expensive [7].

No examples of changes of resin in order to avoid the use of brominated FR-containing PBT or ABS have been identified.

In conclusion, for all identified applications of Deca-BDE in EEE parts made of PBT/PET, alternatives without Deca-BDE are available.

3.3.2 Parts made of polyamide

Polyamide is also known as PA or nylon. Common types of polyamide are PA6 and PA66.

Polyamide is widely used for injection molding applications, often with glass fibre reinforcement. Flame retarded polyamide is used for connectors, circuit breakers and other internal parts of EEE.

Contrary to PBT, a large range of flame retardants have been applied in different types of polyamide.

According to the information presented in Table 3.11, brominated flame retardants account, globally, for the majority of flame retardants used with polyamide for applications in EEE. Different types of PA may require different flame retardants.

A comparison of the technical properties of Albemarle's FRs recommended for use with polyamide shows nearly the same pattern as seen for the other resins. Deca-BDE gives poor performance with regard to bloom resistance and thermal stability, very good performance with regard to colour, and is considered a lower cost solution. It has not been possible to identify any PA application in EEE for which Deca-BDE cannot be replaced by other flame retardants. As shown in Table 3.11, brominated polystyrene is the most widely used FR in polyamide for EEE, with a market share ten times higher that the market share of Deca-BDE.

Table 3.15 Comparison of Albemarle FRs recommended for use with polyamide (based on [[62]])

Notes:
+ + Very Good   + Good   – Fair   – – Poor

HP-7010:                               Brominated polystyrene
BT-93; BT-93W:       Ethylene bis(tetrabromophthalimide)
120:                         Tetradecabromodiphenoxybenzene
8010:                       Ethane-1,2-bis(pentabromophenyl)
102E:                       Deca-BDE

Twelve flame retardants that can be used in addition to Deca-BDE to achieve V-0 grade PA are listed in Table 3.16.

A number of halogen-free flame retardants are available for use in polyamide, and they are widely used. According to Table 3.11, melamine and red phosphorous each represent about 8% of the global FR market for PA made into EE components. According to the information in Table 3.12, the halogen-free FRs accounted for 42% of the total European FR market for PA for all applications in 1998, with melamine accounting for 19% of the total market.

According to SpecialChem, "Melamine cyanurate, is a halogen free, thermally stable flame retardant which has established itself as the flame retardant of choice to achieve UL 94 V-0 especially in unfilled and mineral filled polyamide 6 and 66. Cost effectiveness, excellent electrical and mechanical properties as well as health and safety considerations and freedom of colour are the main advantages of melamine cyanurate." [[63]] However, as shown in Table 3.16, only V-2 can be obtained in fibre-glass-reinforced PA, which is the most demanding PA application for FRs.

Red phosphorous has been used for many years as a FR in polyamide. Red phosphorous can actually be used as a flame retardant additive for a wide variety of plastics. However, it is most efficient in oxygen-containing polymers such as polycarbonate and PA [17]. The red phosphorous concentration required in polyamide for UL 94 V-0 rating, according to the OECD monograph, is about 7% [17]; however, in glass-fibre-reinforced polyamide 66, 10-13% red phosphorous is needed (Table 3.16). According to one producer of polyamide containing red phosphorous (quoted in [7]), the mechanical properties of polyamide are hardly impaired by the small quantities of red phosphorous. One disadvantage of red phosphorous is that, due to its reddish colour, the polyamides can only be offered in the colours grey and black. There are also certain risk factors associated with working with red phosphorous, including flammability and auto-ignition.

Table 3.16 Examples of commercially available flame retardants for V-0 grade PA

*      Source: [62]. It is not specifically mentioned that the loading is for V-0 grade, but it is indicated as typical loading, and the FR efficiency of the substances is similar to that of Deca-BDE.

**    Loadings for products from Ciba [136].

*** The substance is included in a list summarised March 2006 by J. Troitzsch [31]. The loadings of the substance have not been assessed further.

**** Source: Clariant GmbH [64].

It has not been possible to identify any detailed independent assessment of the cost of replacing Deca-BDE with other flame retardants in PA.

Therefore, in the following discussion, an estimate is made on the basis of information obtained from Clariant GmbH - Business Unit Plastic Industries, Germany. Clariant is a major global actor in the field of specialty chemicals, and a manufacturer of a number of halogen-free flame retardants, among which, ammonium polyphosphate, red phosphorous and organic phosphinates. On request, Clariant has provided information for comparison of its newly developed organic phosphinates with three other flame retardants for PA [[64]]. The price estimates of three other flame retardants are based on recent information from market surveys. Any price comparison is, of course, highly dependent on the type of PA and the filling, and this estimate should only be considered as an example indicating the order of magnitude.

The calculation is made for glass-fibre-reinforced flame retarded V-0 grade Polyamide 6 (FR PA 6 GF). It is assumed that the glass fibre loading is 20% (typical loadings are 10-30%). The price of the pure PA 6 is assumed to be 2.3 €/kg (typical range 2.1-2.5 €/kg), and the price of the glass fibre assumed to be 1.95 €/kg (typical range 1.7-2.2 €/kg). The total material price for the PA 6 GF (20%) is then 2.23 €/kg.

In Table 3.17, cost estimates are shown for V-0 grade FR PA 6 GF, flame retarded variously with Deca-BDE, brominated polystyrene, magnesium hydroxide and organic phosphinates. No data on red phosphorous or melamine polyphosphate, two other options, were identified. The prices of the three alternatives range from 84% to 127% of the Deca-BDE option. It should be noted that the high loading of magnesium hydroxide required to achieve V-0 grade may hinder its use for certain applications in spite of the low price. For a 25 g plastic part, these price differences correspond to a cost difference of
(-)0.02 to 0.03 €.

Table 3.17 Comparison of material prices of V-0 grade PA 6 GF with four different flame retardants

Note: Due to differences in density of the FRs, the volume of 1 kg final material will be slightly different. In fact, for the user, the comparison should be done for the same volume, but it is clear that the result would be only slightly different from these estimates. Basic prices and loadings according to [64].

In conclusion, for all identified applications of Deca-BDE in EEE parts made of PA, alternatives without Deca-BDE are available.

3.4 Substitutes to Deca-BDE in cables, sheets and films made of PP and PE

According to the information from the Bromine Science and Environmental Forum shown in Table 2.3, Deca-BDE is used in the polyolefins PP and PE for the following applications:

• Wire and cables - e.g. heat shrinkable tubing;
• Communication cables;
• Building cables;
• Capacitor films.

Building cables, power capacitors and, to some extent, communication cables are beyond the scope of the RoHS Directive.

“Wire and cables” is a very diverse product group, with a number of different plastics and rubber used for cable insulation, as well as several different flame retardants. It has not been possible to identify any source that has quantified the use of Deca-BDE and alternative flame retardants in cables of EEE, nor to identify any specific applications where Deca-BDE provides exceptional properties. According to Bromine Science and Environmental Forum, wire and cabling accounted for 2% of the EE industry's BFR consumption (probably in the late 1990's)  [[65]]

A number of brominated flame retardants are available for use with PE and PP. Properties of FRs from Albemarle Corp. are compared in Table 3.18, showing a similar pattern to that seen for other resins.

Regarding the use of Deca-BDE (SAYTEX® 102E ) and two brominated alternatives for cables and wire, Albemarle Corp. wrote : "SAYTEX® 102E flame retardant is a very effective flame retardant with high % bromine (83%) and high thermal stability (approximately 300°C). Although it is a common FR used in wire & cable, it “blooms,” which affects appearance, moisture resistance, and electrical properties. With good UV resistance, very good thermal stability and low blooming characteristics, thermally stable and high-bromine SAYTEX 8010 flame retardant is well-suited for applications requiring color stability, or where recycling is anticipated. SAYTEX BT-93 brominated flame retardant is very thermally stable (over 450°C), with excellent flame retardant efficiency. It does not bloom, which leads to better moisture resistance and electrical properties." [[66]]

Regarding the brominated alternatives, the situation is very much the same as for HIPS and PA, and the price differences estimated for the latter two resins may roughly be applied to the polyolefins.

Table 3.18 Comparison of Albemarle FRs recommended for polyolefins (based on [69])

Notes:
+ + Very Good   + Good   – Fair   – – Poor

HP-7010:                               Brominated polystyrene
BT-93; BT-93W:       Ethylene bis(tetrabromophthalimide)
120:                         Tetradecabromodiphenoxybenzene
8010:                       Ethane-1,2-bis(pentabromophenyl)
102E:                       Deca-BDE

Halogen-free flame retardants that can be used with polyolefins include intumescent systems and magnesium hydroxide.

Halogen-free solutions for polypropylene, based on intumescent technologies, have been commercially available for many years, but their use and acceptance has been somewhat restricted due to product limitations, especially as regards processing, water extraction, cost performance, and the high load levels required, which cause degraded mechanical properties [142]. The mechanism of FRs based on intumescent technologies is to cause the plastic, when heated, to swell (intumesce) into a thick, insulating char that protects the underlying material from burning by providing a physical barrier to heat and mass transfer.

Many of the existing halogen-free solutions are based on ammonium polyphosphate, combined with different nitrogen sources and other co-additives.

An example is Clariant's ammonium polyphosphate based flame retardant Exolit AP 750: "In comparison to other non-halogen flame retardants, such as aluminum or magnesium hydroxide, Exolit AP 750 is much more effective. The UL 94 standard (Class V-0), which is important in the electrical and electronics industry, is thus achieved with substantially lower dosages." [68]

Another halogen-free FR system, based on melamine phosphate, is Reogard® 1000 (CN-2616): "CN-2616 steps beyond the performance limitations of existing flame retardant solutions for polyolefins with a unique set of properties. It is versatile enough to meet MVSS 302, UL-94 V0 and V5 requirements, and initial results following European test protocols have also been positive." [142]

"We believe that the reduced loading of CN-2616 required to meet UL 94-V0 test requirements and the superior performance in terms of water resistance, electrical and physical properties will lead to increased use of halogen-free polyolefin compounds." [142]

The following table lists Deca-BDE and 12 other flame retardants used with polyolefins to achieve V-0 grade.

In conclusion, for all identified applications of Deca-BDE in EEE parts made of polyolefins, alternatives without Deca-BDE are available.

Table 3.19 Examples of commercially available flame retardants for V-0 grade polyolefins

*      The substances are included in a list summarised March 2006 by J. Troitzsch [31]. The loadings of the substance have not been assessed further.

**    Source: SpecialChem [[69]]. The loading refers to products from Albemarle Corp.

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