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Inclusion of HBCDD, DEHP, BBP, DBP and additive use of TBBPA in annex IV of the Commission's recast proposal of the RoHS Directive

4 Dibutylphthalate (DBP)

4.1 Main concern

The main concern as to dibutylphthalate (DBP) is its possible effect on reproduction and possible long-term adverse effects in the aquatic environment.

DBP is (November 2009) included in the draft list of substances recommended by ECHA for inclusion in the list of substances subject to authorisation in Annex XIV of REACH.

DBP is included in Annex I to Regulation No 1272/2008 (CLP) with the classification Repr. Cat.2; R61: May cause harm to the unborn child, Repr. Cat.3; R62: Possible risk of impaired fertility (Symbol: T), R50-53: Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment (Symbol: N). DBP is on the EU list of substances with endocrine disruption classifications, classified in CAT. 1 “Evidence for endocrine disruption in living organisms” (BKH, 2000)

Due to the possible effect on reproduction the substance shall not be used as substances or as constituents of preparations, at concentrations of greater than 0,1 % by mass of the plasticised material, in toys and childcare articles (Regulation No 552/2009). Further, it is not permitted for use in cosmetics (Directive 2004/93/EC)

An EU Risk Assessment has been finalised for DBP (ECB, 2004). The EU Risk Assessment Report (RAR) concludes that there is a need for limiting the risks for workers, taking the risk reduction measures already applied into consideration. For consumers and humans exposed through the environment the RAR concludes that there is at present no need for further information or testing or risk reduction measures beyond those which are being applied already.

DBP is considered non-genotoxic based on a variety of genotoxicity studies. No adequate long-term toxicity and/or carcinogenicity studies in animals or man are available.

The review undertaken for the European Commission by Öko-institut e.V. as background for selection of candidate substances for a potential inclusion into the RoHS Directive (Gross et al., 2008) recommend DBP as a potential candidate.

4.2 Characterisation of the substance

DBP is a specialty plasticiser used in minor concentrations in some flexible PVC applications as well as in some non-polymer uses such as for example in paints, adhesives, sealants and printing inks (COWI, 2009c). Phthalate plasticisers are always used as so-called external plasticisers, meaning that they are not bound chemically in the polymer matrix. They can therefore migrate out of the plasticised polymer by extraction with soapy water, oils, etc., by evaporation and by diffusion, and thereby become available for exposure to humans via inhalation, skin and diet, as well at to the environment.

The structural formula for DBP (CAS. No 84-74-2) is shown below.

DBP

Illustration: DBP

The following information is, if no other reference is given, extracted from an assessment of the manufacturing and use of dibutyl phthalate (DBP) recently published by European Chemicals Agency (COWI, 2009c).

The total produced tonnage in 2007 in the EU is confidential but it was less than 10,000 tonnes. A significant part of the manufactured tonnage is exported to countries outside the EU and less than 8,200 tonnes was used for formulation in the EU. DBP seems to represent less than 1% of the production of phthalates in Europe. DBP is used in relatively small concentrations in the products and may be present in significantly more than 1% of the products containing phthalates.

The major use, accounting for more than 50%, is polymer formulation and processing. DBP is a speciality fast fusing plasticiser. It is used in PVC as a gelling aid in combination with other high molecular weight plasticisers and is too volatile for PVC applications in itself. The gelling agent is the agent which reacts fastest with the PVC. Dutch surveys of phthalates and other plasticisers in toys and childcare products demonstrated that 30 % of 24 analysed products in 2004 contained DBP (FCPSA, 2008a). The share had decreased to 13% of the products in 2007 and 1% in 2008 as consequence of the regulation (FCPSA, 2008b).

The market for DBP has been decreasing over recent decades: In 1994 the production volume of DBP in the EU was 49,000 tonnes and in 1998 it was 26,000 tonnes, with an export of 8,000 tonnes.

Current uses of DBP, according to actual information obtained from industry or product registers are listed below. In general, limited information is available on the actual uses of DBP in polymers.

  • Gelling aid in combination with other plasticisers in plastics (major use area). DBP is used in PVC (manufacturer information). It has not been possible to obtain very specific information on the uses, but the following applications are mentioned by different sources: floor coverings, automotive uses (manufacturer information) and garden hoses. The European Plastic Converters (EuPC), has in a survey by their members not indentified any use of DBP, and assume that DBP today is used by relatively few companies for different niche purposes. The results of the Dutch surveys show that DBP in 2004 was used at a relatively high frequency in many different types of toys (FCPSA, 2008a).
     
  • Rubbers (manufacturer information). The Risk Assessment for DBP (ECB, 2004) specifies that DBP is used in some polychloroprene rubber (neoprene) and nitrile rubber, but not in all. New information on actual uses is not available.
     
  • DBP is used in the adhesives industry to plasticise polyvinyl acetate (PVA) emulsions. The low viscosity and compatibility of DBP make it suited for PVA-based adhesives for bonding cellulosic materials. According to the Risk Assessment for DBP (ECB, 2004) the most important uses of the adhesives are for paper and packaging, wood building and automobile industry.
     
  • Epoxy resins. Probably same application that in the Risk Assessment for DBP (ECB, 2004) is mentioned as "solvent in the production of fiber glass". More specific information on this application has not been available.
     
  • In the coatings industry as a primary plasticiser-solvent for nitrocellulose lacquers.
     
  • Grouting agents, used to reduce water leakages in tunnels, sewer systems, buildings etc. DBP contents as high as 30-60% were found in polyurethane foams used in grouting applications for water control in tunnels, sewer systems, buildings etc. No actual confirmation of this application has been obtained.
     
  • Other applications:
     
  • Solvent for many oil-soluble dyes, insecticides, peroxides and other organic compounds;
  • Antifoam agent and as a fibre lubricant in textile manufacturing;
  • Used in compounding flavours;
  • Printing inks, polishing agents, corrosion inhibitor materials;
  • Use in polypropylene (PP) catalytic systems;
  • One application described in the confidential part of the ECHA report.

According to European Council of producers and importers of paints, printing inks and artists’ colours (CEPE), DEHP, BBP and DBP are no longer used in printing inks by CEPE or European Printing Ink Association (EuPIA) members following its classification as reprotoxic category 2.

It was for the ECHA report (COWI, 2009b) not possible to obtain comprehensive quantitative updated information on the use of DBP for the different uses from manufacturers and suppliers and the available information did not allow real estimates of the distribution between the different use areas to be made.

4.3 Applications in EEE

While the use of DBP in EEE has not been identified in this study, and DBP has already been substituted in many of its former applications (consumption has decreased significantly), it cannot be ruled out that DBP may be used in EEE parts or manufacturing processes. Based on the above mentioned general knowledge of DBP applications, the possible applications areas of DBP in flexible polymers and plasticised non-polymers used in EEE are shown in Table 4.1.

The most likely applications are in PVC parts together with other plasticisers (e.g. DEHP) and in adhesives.

Table 4.1
Potential (unconfirmed) uses of DBP in EEE

Click here to see Table 4.1


4.4 Quantities of the substance used

No estimates of DBP consumption in EEE have been found. Such estimates are hard to form due to lack of confirmation of DBP usage in EEE parts. The earlier mentioned frequencies of DBP in toys prior to the ban for this sector indicate however, that DBP usage in flexible PVC could potentially be widespread. On the other hand, European Plastic Converters (EuPC), has in a survey by their members not indentified any use of DBP, and assume that DBP today is used by relatively few companies for different niche purposes.

Less than 8,200 t/y of DBP are used for production in the EU. Of this, the majority (less than 5,900 t/y) is used as secondary plasticiser in production of polymer parts, mainly of PVC. No application in EEE is specifically mentioned by suppliers. Less than 1,890 t/y was used in PVA and other adhesives, and 160 t/y was used in paints (COWI, 2009c). Both may to some extent be used in EEE. The remaining 330 t/y are not deemed relevant for EEE applications. A minor share of the relevant consumption of DBP may be used in EEE parts; probably below 10% based on the many other potential application areas. The consumption of DBP for EEE production in the EU is therefore likely in the range of 50-500 t/y.

An additional, but unknown amount may be present in imported EEE and imported EEE parts.

4.5 Available alternatives

Much of the DBP usages have likely been substituted for by di-isobutyl phthalate (DiBP), a very similar group of substances which have similar technical performance characteristics. DiBP has however been proposed as a SVHC (substance of very high concern) due to CMR characteristics (DiBP Annex XV, 2009). Other available alternatives to DBP appear to be dibenzoates such as dipropylene glycol dibenzoate (DGD), the mixed dibenzoates product Benzoflex 2088 and dibutyl terephthalate (DBT). With adjustments of the polymer/plasticiser formulations, and in some cases processing adjustments, these alternative plasticisers are reported by producers to perform technically suitably as alternatives to DBP as specialty PVC plasticisers. There are also other alternatives to DBP, but some of these currently suffer from relatively high prices compared to DEHP and DBP (COWI, 2009).

With its faster, lower temperature, gelling characteristics compared to general plasticisers as DEHP and DINP, using alkylsulfonic phenylester (ASE) as the primary plasticiser may reduce the need for adding a gelling aid like DBP. ASE is however currently somewhat more expensive than DEHP/ DBP(COWI, 2009).

Another alternative to using DBP in PVC is to simply omit its use, and accept the potentially altered production characteristics such as slightly slower production or slightly increased energy input for gelation of the polymer.

There might be some special non-polymer applications where extensive R&D would be necessary for obtaining the desired properties of the final products with alternative plasticisers, but no specific information on such applications has been identified.

4.6 Socioeconomic impacts

4.6.1 Substitution costs

The substitution costs will mainly fall at the processors and formulators of PVC and other potentially DBP containing materials such as sealants, glues, etc. For coatings and other integrated parts, the EEE manufacturers may act as PVC processors themselves, and may need to be involved in reformulation of the PVC plastisols (suspension of PVC particles in a plasticizer) or compounds used. The plasticiser producers will normally be involved in the substitution, because they act as advisors for the processors and formulators in the formulation of the polymer/plasticiser system. The alternative plasticisers are already developed and marketed, but costs for increasing the production volume may be implied. One of the alternatives to using DBP is to simply omit its use. This may result in increased production time and thereby potentially increased production prices. All substitution costs are expected to ultimately be furthered to the end customers.

Table 4.2 shows price examples of BBP, DEHP and selected alternatives to DBP. We have not found current prices for DBP, but it has been reported to traditionally be in the same price range as DEHP. As shown, DGD and Benzoflex 2088 had comparable or slightly higher prices per weight than DEHP, while ASE had a somewhat higher price per weight. Note that alternatives may not be used in the same amount as DBP to obtain the properties of the polymer; data are not available for a closer comparison. Many PVC products are sold in highly competitive markets, and PVC processing industry is sensitive to even minor price changes on raw materials (TURI, 2006).

Table 4.2
Examples of comparative prices of DEHP, BBP and selected alternatives (from COWI, 2009)

Substance Price, Relative price to
DEHP and BBP, %		 Remarks
DEHP (2006) 0.70 USD/Lb 100% TURI (2006)
BBP (2006) 0.70 USD/Lb 100% TURI (2006)
Benzoflex 2088   "Slightly higher" Genovique (2009)
DGD (2006) 0.73 USD/Lb 104% TURI (2006)
ASE €1,75/KG 175% *1 Lanxess (2009)

Notes: *1: DEHP € price in 2006-2009 ˜0.8-1€/kg; 1€ is used for calculations.

For most EEE, the parts which may contain DBP comprise only a minor fraction of the equipment/product and thus also only a minor part of the total production price of the product. If used at all for this equipment, DBP and alternatives are only used in small concentrations, further decreasing importance of the secondary plasticisers' price in this context. Also, considerable fractions of the flexible PVC and other materials used in EEE may already be formulated with other specialty plasticisers instead of DBP. Increases in consumer prices for EEE as a result of a restriction of DBP use in EEE are therefore expected to be minimal or even negligible.

4.6.2 Impacts on supply chain

SMEs
The considerations regarding impacts on SME are the same as for DEHP, and reference is made to section 3.3.

EU production
DBP and ASE are examples of plasticisers produced by relatively large or multinational European based companies. DGD and Benzoflex 2088 are currently produced in the USA.

Production of EEE is substantial in the EU, however a large part of the total end-user consumption of EEE is imported as finished goods from outside the EU. This is notably the case for small household appliances, consumer electronics, IT equipment, and toys etc., but also for other EEE groups.

For EU based EEE producers, DBP containing parts may be produced by themselves or by subcontracting PVC processing or non-polymer formulator companies in the EU as well as on the world market.

Differences in restriction of the use of the substance via the RoHS Directive or via REACH are discussed in section 1.3.

4.6.3 Impacts on waste management

As DBP is to a large extend used in smaller parts, their treatment when disposed off will follow the EEE products they are parts of, and a change in plasticiser will likely not in itself form the basis of changes in the solid waste handling scheme for EEE. No changes in solid waste handling costs are expected as a consequence of prohibiting the use of DBP in EEE.

4.6.4 Administrative costs

Extra compliance costs related to the addition of one new substance under RoHS are expected to be minimal for companies which have already implemented RoHS, that is, most of the relevant companies. DBP use in polymers would typically be in parts where lead and cadmium have traditionally also been used (e.g. in pigments, stabilisers) and compliance documentation would usually be required for such parts. Additional compliance documentation may be required for non-polymer applications e.g. adhesives. No data are available on how many companies could be affected by RoHS regulation because of the inclusion of DBP. This cost element is therefore not included further in the assessment made here.

The main extra costs are estimated to be related to control; both by the manufacturers, importers and the authorities. The presence of DBP cannot be determined by simple XRF screening, therefore sampling, extraction and laboratory analysis is required. The parts that may contain DBP (mainly flexible PVC parts) typically also may contain DEHP and other RoHS substances e.g. lead and cadmium, but the presence of metals can be determined by a simple XRF screening.

The extra costs would therefore comprise the costs of sampling, sample preparation and analysis.

Brominated flame retardants (e.g. the PBDEs) and phthalates can be extracted by the same organic solvents and analysed using the same GC-MS analysis (gas chromatography followed by mass spectroscopy), however, usually the materials containing the brominated flame retardants are different from the materials containing phthalates.

In PVC and other polymers DBP may be used together with DEHP which is used in much larger quantities in EEE. The price of an analysis of DEHP in a flexible PVC is in Denmark is reported to be about 160 € (excl. VAT) while the total price of analysing for DEHP, DBP and BBP is about 190 € (excl. VAT).The extra costs of analysing for DBP and BBP if analysis for DEHP is already done is thus about 30€ (excl. VAT). All prices are per sample when more than 20 samples are analysed.

For non-polymers parts like adhesives and paints, it may be necessary to take extra samples – if possible at all – in order to analyse for the presence of DBP (and eventually other regulated phthalates). There is at the moment no simple “rule-of-thump” telling where the substances could most likely be found and they are probably present at a very low frequency.

4.7 Impacts on health and environment

4.7.1 Impact profile of substance and alternatives

Environmental and health properties of alternatives to DEHP, DBB and DBP have reviewed for ECHA (COWI, 2009a,b,c) as part of the evaluation of substances for inclusion of substances on the candidate list of SVHC for authorisation. These substances and other alternatives have further recently been reviewed in a study for the Danish EPA (Maag et al., 2009).

Study for the Danish EPA on environmental and health properties of alternatives to DEHP, DBP and BBP
The results of the study as regards environmental and human health properties are summarised in Table 3.4 in section 3.7.1. Data for DEHP, BBP and DBP, based on data in the EU Risk Assessment report of each substance, is summarized in the table using the same notation. The table includes substances that are mainly alternatives to DBP or BBP, but as the substitution is typically not a one-to-one substitution, but often is a replacement of one plasticiser system (e.g. with DEHP as primary and DBP or BBP as secondary plasticiser) with another system (with more substances together), it is convenient to keep the information on all the substances together in one table.

The results from the study indicate that a number of alternatives to DBP exist which may potentially be less problematic than DBP with regard to human health effects. However, for most of these substances data are missing for critical endpoints, in particular for carcinogenicity, where tests are only available for 3 out of 10 potential alternatives. Compared to DBP and based on the available studies, the alternatives appear to be less toxic than DBP. Like DBP, all except GTA, have some effects on body weight, liver or kidney in repeated dose toxicity studies. With regard to reproductive toxicity, 3 of the 10 studied alternatives have some indication of developmental effects, although with considerably higher NO(A)EL values compared to DBP. For 3 alternatives carcinogenicity is studied in combined chronic toxicity/carcinogenicity studies with negative outcome. Only one study was a guideline study.

With regard to environmental effects of the alternatives, useful fate data regarding biodegradability (in water) and bioaccumulative properties (either as BCF or log KOW) are available for all alternatives while other fate data are quite variable and incomplete. Concerning ecotoxicological effect data, results from short-term tests with the base-set of organisms - fish, crustaceans and algae - exist for all 10 substances although the duration of some studies deviate from the current OECD standard.

None of the alternatives are considered PBT or vPvB substances. One of the 10 studied substances did not show any aquatic toxicity and is also not considered persistent or bioaccumulative whereas the other substances show positive results in one or more of these areas. From an environmental point of view only few of the substances stand out as less problematic compared to DBP.

4.8 Conclusions for DBP

The main concern as to DBP is the substance’s possible effect on reproduction and possible long-term adverse effects in the aquatic environment.

The substance is with regard to human health classified as toxic to reproduction. According to the EU Risk Assessments DBP is bioaccumulative and toxic to aquatic organisms, but not persistent in the environment. DBP is therefore not considered PBT substances or vPvB substances. With regard to CMR effects the Risk Assessments conclude based on the available studies that DBP is not considered genotoxic and are also not carcinogenic to humans.

It has not been possible to fully confirm that DBP is currently used in the manufacture of EEE. The consumption of DBP for EEE production in the EU is likely in the range of 50-500 t/y mainly as secondary plasticiser in PVC and in adhesives and other non-polymer applications. The plasticiser may be present in a low percentage of products within all product categories.

The use of DBP in EEE is not deemed essential as technically suitable alternatives are available and already used today, however it cannot be ruled out for some specific non-polymer applications substitution may be particular difficult.

All available data indicate that alternatives exist, for example DGD, Benzoflex 2088 and ASE. For PVC plasticisation, omitting the use of a fast gelling secondary plasticiser as DBP may also be technically possible, although probably with increased PVC processing expenses as a consequence.

Costs - For most EEE, the parts which may contain DBP comprise only a minor fraction of the equipment/product and thus also only a minor part of the total production price of the product. Price difference between the substance and alternatives is approximately the same as for DEHP. As the consumption of the substance is only about one percent of the consumption of DEHP the increases in consumer prices for EEE, as a result of a restriction on the use of DBP in EEE, are therefore expected to be minimal.

DBP is typically used in plastic components where lead and cadmium have traditionally been used as pigments and stabilisers; however these can be determined by a XRF screening. Further, the phthalates are typically used in other plastic parts than the brominated flame retardants. The main extra administrative costs are estimated to be related to compliance control, where the extra costs would comprise both the costs of sample preparation and analysis. The price of analysis for DEHP, DBP and BBP is nearly the same as for analysis of DEHP only.

The scattered use of DBP in non-polymer applications in EEE may result in relatively high costs of compliance control as relatively many samples have to be taken. For non-polymer applications compliance control will be particular difficult and will imply control of materials not otherwise controlled for other RoHS substances.

Benefits - When comparing the known toxicity of the alternatives with DBP based on the NO(A)ELs for the most critical effect, reproductive toxicity for the three alternatives with developmental effects, the alternatives in the Danish EPA study show these effects at comparable dose levels to DBP. Substances that have been tested for reproductive toxicity with negative outcome (ASE, ATCB, DEHT, DINCH, GTA) seem to be more suitable alternatives based on health effects.

The available data indicate that a number of alternatives exist which do not meet the PBT criteria, but for which more details and evaluation is necessary to conclude about their environmental effects compared to DBP. However, based on the Danish EPA assessment DINA and GTA appear to be more environmentally friendly compared to DBP whereas the other 8 substances have positive responses for more than one of the effects: persistence, bioaccumulation and toxicity. With regard to endocrine disruptive effects DBP is on the EU list of substances with clear evidence of endocrine disrupting effects. None of the alternatives are on the list and data for this endpoint has not been available for evaluation in the Danish EPA assessment.

With regard to the overall assessment, the uncertainty concerning human health effects, in particular reproductive toxicity and carcinogenicity, needs to be considered.

 

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Version 1.0 March 2010, © Danish Environmental Protection Agency