Analysis of Alternatives for Titanium dioxide as colourant additive in plastic industry

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Theodora Barbara Greer
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1 Analysis Alternatives for Titanium dioxide as colourant additive in plastic industry Date: 23 September 2016 Version: 0.3 Authors: Miguel Estebaranz and Patrick de Kort Under the supervision : Gefroy Tillieux, Director Regulatory Compliance Contact : patrick.de.kort@pceu.eu

2 Table Contents 1 Introduction Method Results Calcium Carbonate Zinc Oxide Kaolin and Talc TiO Conclusion and Discussion... 5 Annex I

3 1 Introduction On 31 st May 2016, the European Chemicals Agency published an annex XV dossier compiled by the French Agency ANSES proposing the classification Titanium dioxide 1 as a carcinogen 1B through inhalation. This substance was included in the Community Rolling Action Plan for evaluation chemicals (CoRAP), thus indicating further regulatory action is envisaged by competent authorities. In order to evaluate possible alternatives already used or evaluated, the European Plastic Converters (EuPC) developed and circulated a questionnaire amongst a segment its members to obtain information about these compounds as well as TiO2. In this article the results collected by Polymer Comply as well as the methodology used are presented and discussed. 2 Method The method used was a grid question to evaluate TiO2 as well as the possible alternatives (see Annex I). Possible alternatives were suggested based on information obtained in literature 2 and respondents were invited to propose other alternatives. Respondents were asked to rate these possible alternatives on a Likert scale (1, the worst to 5, the best) for the following properties: whiteness, food preservation, writeability, opacity, weatherability, and chemical, colour and mechanical stability. The proposed alternatives included in the question were: Calcium Carbonate (CaCO3) 3 ; Zinc oxide (ZnO) 4 ; different clay minerals: kaolin, talc, perlite, vermiculite, calcined clays and flash calcined clays; Cenospheres; and Hollow spheres. Furthermore a space for other comments was added in order to give the possibility to the companies to contribute with qualitative remarks. 3 Results 16 responses to the questionnaire were collected. All them evaluated TiO2, specially its whiteness and colour stability. The results TiO2 are highly positive for all properties, with scores above 4.3, and a total average all properties CAS M. J. A. RUSZALA, N. A. ROWSON, L. M. GROVER, AND R. A. CHOUDHERY: Low Carbon Footprint TiO2 Substitutes in Paint: A Review, October 2015, International Journal Chemical Engineering and Applications, Vol. 6, No H. ZWEIFEL, R.D. MAIER, M. SCHILLER: Plastics additives handbook 6 th Edition, CAS CAS

4 Table 1 Analysis Alternatives to TiO2. Average values for each alternative s properties and the number responses between brackets. Chemical Whiteness Food preservation Opacity Writeability Weatherability Stability Chemical Colour Mechanical Average TiO 2 4,87 (16) 4,5 (2) 4,33 (3) 4,71 (7) 4,71 (7) 4,83 (12) 4,8 (15) 4,36 (11) 4,6 CaCO 3 2,1 (15) 3 (2) 4,67 (3) 3,17 (6) 2,17 (6) 3 (7) 2,6 (10) 3,1 (10) 3,0 ZnO 2,75 (8) 3,5 (3) 3,33 (3) 4 (4) 2,67 (6) 3 (6) 3,14 (7) 3,33 (6) 3,2 Kaolin 2,125 (8) 2,5 (2) 4 (2) 3 (4) 2,5 (4) 4,25 (4) 3 (5) 3,5 (4) 3,1 Talc 1,92 (12) 2,5 (2) 4 (2) 2,8 (5) 2,67 (6) 4,33 (6) 2,86 (7) 3,57 (7) 3,1 Perlite 2 (1) (0) (0) (0) 1 (1) (0) 1 (1) (0) - Vermiculite 2 (1) (0) (0) (0) 1 (1) (0) 1 (1) (0) - Calcined clays 1,5 (6) 2 (1) 4 (1) 2,5 (2) 2 (3) 4,33 (3) 3 (3) 3,33 (3) 2,8 Flash calcined clays 1,33 (3) (0) (0) (0) 1 (1) (0) 1 (1) (0) - Cenospheres 2 (1) (0) (0) (0) 1 (1) (0) 1 (1) (0) - Hollow spheres 2 (3) (0) (0) 3,5 (2) 2,5 (2) 4,5 (2) 2,67 (3) 2 (1) - Lithopone (ZnS + BaSO4) 4 (1) 4 (1) 5 (1) 4 (1) 3 (1) 3 (1) 3 (1) 3 (1) 3.6 Barium sulphate 1 (1) (0) (0) (0) (0) 5 (1) 4 (1) 5 (1) - Antimony Trioxide (Sb2O3) 4 (0) (0) Zinc sulphide 2.5 (2) (1) 3 (1) 4.5 (2) 4 (2) 5 (2) - The most evaluated alternative is Calcium Carbonate, followed by Zinc Oxide, Kaolin, and Talc. On other alternatives there is not sufficient data to make general statements on the appropriateness the alternative for the plastic converting sector. 3.1 Calcium Carbonate Calcium Carbonate has an average score 3,0 which is comparable to other alternatives, but low compared to TiO2. The whiteness Calcium Carbonate is also an issue. One respondent even indicated not to consider Calcium Carbonate a pigment, but rather a filler additive. Furthermore, as Calcium Carbonate is able to react with acid following the following reaction: CaCO H + Ca 2+ + H 2 O + CO 2 It might be compromised in outdoor applications, which is reflected in the score 2,17 for weatherability. 3.2 Zinc Oxide Apart from being an inferior whitening agent as determined by various scores, respondents indicated that this substance is also classified as very toxic to aquatic life 4

5 and very toxic to aquatic life with long lasting effects. Thus substitution TiO2 by ZnO might not be the best solution Kaolin and Talc Kaolin and Talc are clay minerals which are generally considered to be fillers and not colourants. The loading levels required to obtain similar whiteness as a plastic whitened with TiO2 are much higher for these substances, which can cause problems in terms mechanical properties the plastic. 3.4 TiO2 Various companies remarked the fact that the TiO2 is the only colourant that gives such a white colour with stability. Several respondents indicated that to achieve similar properties as plastics coloured with TiO2, one would need to add other additives with consequent substantial cost increases for the end product. The same situation would be for UV absorbent properties. One them stated that only TiO2, ZnO and Lithopone are white pigments, the other alternatives CaCO3, clay, talc, Kaolin are fillers and do not impart really opacity to a film and pointed out that TiO2 has good weatherability, and according to another respondent these alternatives are generally fillers developed for incorporation into the polymer matrix alongside TiO2 in order to reduce cost. Great importance was given to TiO2 for being a cost effective whitening agent. One respondent described TiO2 as: undoubtedly the most efficient and cost-effective material to provide opacity and whiteness to plastics. The fact the need to add higher concentrations to a reach TiO2 properties was indicated as well. One respondent explained about this: the best the alternative materials would require four or five times the concentration to achieve similar levels opacity and would not approach the whiteness provided by TiO2. Some respondents concluded that currently following extensive evaluation there are no suitable alternatives available within the market place to this compound. 4 Conclusion and Discussion Based on the quantitative results obtained by this questionnaire and the qualitative comments, we can conclude that at this moment there is no viable alternative to TiO2 as colourant additive in plastics. As it has been discussed in the above, the amount alternative additives that would be needed to added would increase the cost the final product, but also would decrease its quality. Furthermore, several respondents highlighted that alternatives might have a detrimental effect on the environment and/or human health. 5 A full evaluation the classification the alternatives can be found in annex I 5

6 Annex I We provide here a classification the compounds abovementioned, the Harmonised ones and those that are associated to some C&L according to companies notifications. Name CAS number Harmonised C&L inventory 6 H-Phrase Not Classified 2482 Carc. 2 H Titanium dioxide (TiO 2) Acute Tox. 4 Carc. 2 STOT SE 3 STOT RE 1 Carc. 2 STOT SE 2 H332 H351 H335 (Affected organs) H372 (Affected organs) H351 H371 (Respiratory sys...) Calcium Carbonate (CaCO 3) H-Phrase Not Classified 1790 Skin Irrit. 2 H Skin Irrit. 2 H315 Eye Dam. 1 Skin Irrit. 2 Eye Dam. 1 STOT SE 3 H318 H315 H318 H335(respiratory sys...)(inhalation) Only s with more than 10 notifiers have been included in this table 6

7 Name CAS number Harmonised C&L inventory 6 Zinc oxide (ZnO) H-Phrase Aquatic H Acute 1 H410 H-Phrase Kaolin Not Classified Skin Irrit. 2 H STOT RE 2 H373 (Lungs) (Inhalation) 27 STOT RE 1 H372 (Lungs) (Inhalation) 27 Talc H-Phrase Not Classified Carc. 1A H Acute Tox. 4 H Acute Tox. 4 H Acute Tox. 4 H STOT RE 1 H372(Lungs) 13 7

8 Name CAS number Harmonised C&L inventory 6 Perlite Vermiculite H-Phrase Not Classified 147 Skin Irrit. 2 H Zinc sulphide (ZnS) H-Phrase Not Classified 508 Skin Sens. 1 H317 Resp. Sens. 1 H Aquatic H410 Chronic 1 18 STOT SE 3 Aquatic Acute 1 H335(respiratory irr...) H Acute Tox. 4 H Antimony Trioxide (Sb 2O 3) H351 Lithopone (BaO 5S 2Zn 2) H-Phrase Not Classified 32 Acute Tox. 4 H302 Acute Tox. 4 H

9 Av. de Cortenbergh Brussels Belgium 9

Comments CLH proposal Cadmium hydroxide

1 Comments CLH proposal Cadmium hydroxide GENERAL COMMENTS: The International Cadmium association (ICdA) welcomes the opportunity to provide its contribution to the public consultation on the proposed