Plasticizers
Plasticizers or softeners ( English plasticizer , causing) substances that softer, more flexible, pliable and elastic are.
Plasticizers act as solvents . They cause plastics to swell and transform them into a gel-like state. When plasticizers escape again, the fabric shrinks, becomes more brittle, harder and possibly cracked. A neighboring substance in which the Weimacher migrates can become sticky or, in the worst case, liquefy. The lower the vapor pressure of a plasticizer, the lower its tendency to evaporate. Esters of phthalic acid and phosphoric acid are often used as plasticizers.
87% of the plasticizers used in 2012 were used in plastic products (mostly in foils and cables), followed by rubber products, paints and varnishes . In addition, they are also used in adhesives and film coatings.
Plasticizers are among the best-selling chemicals . These include, for example, low-volatility carboxylic acid esters , fatty oils , soft resins and camphor . They shift the thermoelastic range to lower temperatures so that the plastic has the desired elastic properties in the operating temperature range.
Some plasticizers are harmful to health and the environment. Phthalates in particular , which make up a 70% market share in plasticizers, are known for this and are now banned in many applications.
Methods and Examples
Examples of plasticizers that are added to plastics:
External softening
With external plasticization, the plasticizer is not covalently bound into the polymer, but only interacts with the polymer via its polar groups ( dipoles ) . The small, mobile plasticizer dipoles push themselves between the chain molecules of the polymer and bind to their dipoles. This loosens the chain molecules and makes them more flexible. Likewise, the softness and elongation of the plasticized polymer increase, so that the tensile strength is reduced. There are hinge and shield plasticizers.
- Diethylhexyl phthalate (DEHP) is used as a plasticizer for PVC and elastomers and is still by far the most widely used plasticizer. (As, among others, an EU working group in 2000 due to various negative assessments teratogenic and toxicity to human reproduction classified), the European plastics industry does without phthalates in toys for toddlers. DEHP has also been detected in olive oil . Another, more colloquial term for DEHP is dioctyl phthalate ( DOP ). DEHP belongs to the group of phthalic acid esters .
- Mesamoll , an alkyl sulfonic acid ester of phenol (ASE), plasticizer for PVC, serves as a substitute for DEHP .
- Hexamoll DINCH is another substitute for DEHP and has been used since 2006 for the production of plastic articles for sensitive areas of application such as children's toys made of PVC , medical articles and for food packaging.
- Citric acid-based plasticizers such as triethyl citric acid are more expensive than phthalate-based plasticizers, but they are hardly toxic and do not have any hormone-like effects.
- Adipic acid- based plasticizers, especially diethylhexyl adipate and diethyloctyl adipate, are used in a similar way to citrate-based plasticizers. Although they are less toxic than phthalates, they are also more expensive.
Internal softening
In addition to these methods known as external softening, there is also what is known as internal softening. In this case, the plasticizer is introduced as part of a copolymerization . In contrast to external plasticization, in which the plasticizer is only linked to the macromolecules via intermolecular interactions, with internal plasticization it becomes part of the macromolecule (in the case of a copolymer). This increases the distances between the individual macromolecules, reduces the intermolecular forces of attraction and increases the mobility of the chains. The plastic therefore remains permanently soft and the plasticizer does not diffuse out. For example, vinyl chloride is polymerized with up to 20 percent vinyl acetate . The copolymers of vinyl chloride are required for processing techniques at low temperatures and as paint and adhesive raw materials. Other additives for the copolymerization of vinyl chloride are maleic acid , ethene , methyl vinyl ether or acrylic acid methyl ester .
Extender
Extenders are secondary plasticizers that have a moderate polarity and are therefore only used in coordination with the actual plasticizers. They serve to improve processing and to make the plastic molding compound cheaper. Chlorinated paraffins and epoxidized vegetable oils are often used as secondary plasticizers .
Plasticizers in the tablet industry
Plasticizers are added to produce coated tablets with the aid of polymer solutions or polymer dispersions. These are often low-molecular, high-boiling liquids such as dibutyl sebacate with a boiling point of 343 ° C. The aim is to reduce the brittleness of the coatings and to increase their flexibility. In addition, plasticizers reduce the minimum film-forming temperature . This should ideally be at room temperature. Plasticizers are deposited between polymer chains and thus increase the flexibility and elasticity of the chains. They reduce brittleness and, in connection with polymer solutions for coatings, lower their minimum film-forming temperature.
Abbreviation according to DIN EN ISO 1043-3
Analytics
The reliable qualitative and quantitative determination of the various plasticizers is possible after appropriate sample preparation by using the coupling of gas chromatography with mass spectrometry or by coupling HPLC with mass spectrometry . The methods are also suitable for determining the plasticizers in plastic toys. Also in edible insects recently on the market (Orthoptera, Coleoptera, Lepidoptera, Hemiptera, Odonata, Hymenoptera) plasticizers could be detected in small amounts using the method described.
Health effects and consequences
It is not possible to make a general statement about the effects of “plasticizers” because different groups of chemicals are so designated depending on the application. The main criticisms are plasticizers for plastics that are inherently brittle .
Certain plasticizers based on phthalates can cause infertility in men, as they are similar in their effect certain hormones. The member states of the European Union (EU) classified the phthalates DEHP, DBP and BBP as toxic to reproduction. They influence the testosterone-controlled development stages. They are also suspected of causing diabetes . Bisphenol A, which is added as a necessary antioxidant - i.e. associated with it - is also suspected of having health effects.
The routes of exposure for humans are contaminated food (main part of total intake), inhalation, drinking water, breast milk, and skin contact with cosmetics or thermal paper (up to 15% of the total exposure, contained e.g. in bills, parking tickets, entrance tickets etc.) in which phthalates are in particularly easily soluble form and can be absorbed through the skin.
Phthalate plasticizers have been banned by the European Union for children's toys, but have still been found in many colored pencils . This is dangerous for children in the long run, as they can be harmed to health by chewing on the painted surfaces.
In German kindergartens, three times as high levels of exposure to various plasticizers were found on average as in an average German household. This is a cause for concern, because plasticizers are suspected of influencing the hormonal balance. This is particularly dangerous for children and fetuses in the womb: Infertility, liver damage or behavioral disorders could be triggered or promoted.
Alternatives to plasticizers from the phthalate group can only be used with a simultaneous re-optimization of physical and chemical properties; there is no simple substitute substance. The alternatives to bisphenol A, bisphenol S and F, were found to be hormonally active in current studies and are suspected of having effects similar to bisphenol A on reproduction, metabolism and neurological functions in humans and marine organisms. Bisphenol S and F as ingredients, as well as many other plasticizers in products are not subject to labeling in Germany. However, according to the European Chemicals Regulation REACH, manufacturers and companies are obliged to provide concerned consumers with information about all the constituents and their hazards on request.
Impact on the environment
The release of phthalates through leaching or abrasion occurs predominantly in outdoor applications: for example from underbody protection, from roofing foils or from truck tarpaulins. When cleaning PVC floors or washing PVC-printed textiles, phthalates also get into the wastewater. In the sewage treatment plants, they mainly accumulate on the sewage sludge. If this sewage sludge comes into the fields, phthalates get into the soil. Occasionally they could even be detected in the groundwater. Some phthalates have already been classified in an EU risk assessment (2007) as “persistent” (long-lived in sediment and soil), “bioaccumulating” (accumulating to a high degree in organisms) and “toxic” (toxic to aquatic organisms). For many plasticizers, however, no data are available in this regard.
Occurrence and Politics
While polyethylene and polypropylene , which for example make up the majority of food packaging films and trays, normally do not contain any plasticizers, plasticized PVC always consists partly of plasticizers (typically 30 to 35%). Plasticizers can be found in children's toys made of PVC and often in sex toys from the Far East. When purchasing such products, it is essential to pay attention to the labels “free from plasticizers / phthalates” and “BPA-free”, as they are not yet banned in the EU. However, “BPA-free” is not the same as bisphenol-free, because instead of bisphenol A, another bisphenol is often used that does not have to be declared. As early as the end of 1999, the EU had issued a three-month ban on certain plasticizers for toddler toys that are intended to be put in the mouth. This temporary measure has always been extended by three months to this day. The use of phthalates was banned because there was no reliable measurement method to measure the migration of the phthalates and thus the possible exposure of children. A method validated by the European Chemicals Bureau ECB is now available.
The global volume of plasticizers in 2004 was 5.5 million tons, which corresponded to a total value of around 7 billion euros. In 2014, global consumption was estimated at 8 million tons, of which phthalates made up 70%.
Individual evidence
- ↑ Leaflet on material compatibility - material compatibility around insulating glass - insulating glass sealants, glazing sealants, blocks , Bundesverband Flachglas - wholesale insulating glass production, Veredelung eV, 6/2014.
- ^ Painter Wiki - Softener , In: Mappe.de. Accessed May 2020.
- ↑ a b c Ceresana Research: Plasticizers market study , November 2013.
- ↑ a b c Entry on plasticizers. In: Römpp Online . Georg Thieme Verlag, accessed on May 14, 2020.
- ↑ Plastics Additives By G. Pritchard (Chapter 4.13.5) limited preview in the Google book search.
- ↑ Vogel: plastics science . Würzburg 2005 (8th edition), ISBN 3-8023-1987-7 , p. 50.
- ^ Frank Massholder: What is plasticizer: Food chemistry: definition, product knowledge, food science. Retrieved May 19, 2020 .
- ↑ Entry on dibutyl sebacate in the GESTIS substance database of the IFA , accessed on December 10, 2009(JavaScript required) .
- ↑ Xiang W, Gong Q, Xu J, Li K, Yu F, Chen T, Qin S, Li C, Wang F: Cumulative risk assessment of phthalates in edible vegetable oil consumed by Chinese residents. , J Sci Food Agric. 2020 Feb; 100 (3): 1124-1131, PMID 31680259 .
- ↑ To J, Kim YY, Cho HD, Kim J, Lee JY, Lee Y, Jo E, Lee J, Cha S, Han SB: Development and investigation of a QuEChERS-based method for determination of phthalate metabolites in human milk. , J Pharm Biomed Anal. 2020 Jan 2; 181: 113092, PMID 31915107 .
- ↑ Meng X, Zhang N, Sun X, Niu Z, Deng Y, Xu J, Bai H, Ma Q: Suspect screening of 200 hazardous substances in plastic toys using ultra-high-performance liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry. , J Chromatogr A. 2019 Dec 27: 460830, PMID 31902577 .
- ↑ Poma G, Yin S, Tang B, Fujii Y, Cuykx M, Covaci A: Occurrence of Selected Organic Contaminants in Edible Insects and Assessment of Their Chemical Safety. , Environ Health Perspect. 2019 Dec; 127 (12): 127009, PMID 31891522
- ↑ "45 Min - Danger of Plasticizers": Why are more and more men only fertile to a limited extent? .
- ^ Federal Environment Agency: "Phthalates - the useful plasticizers with undesirable properties" , accessed on May 1, 2015.
- ↑ Medizinauskunft.de: Plasticizers make sterile ( Memento from September 5, 2011 in the Internet Archive ), March 22, 2010.
- ↑ Medicine - Communication: DGE warns of plasticizers in plastic: Phthalates favor type 2 diabetes. Working group of the scientific medical societies, press release from May 29, 2012 from Informationsdienst Wissenschaft (idw-online.de), accessed on May 15, 2015.
- ↑ S. Net, R. Sempere, A. Delmont, A. Paluselli, B. Ouddane: Occurrence, fate, behavior and ecotoxicological state of phthalates in different environmental matrices. In: Environmental Science & Technology . Volume 49, Number 7, April 2015, pp. 4019-4035, doi : 10.1021 / es505233b , PMID 25730609 .
- ↑ EFSA press release July 2013: "Food is the most important source of BPA for consumers, and thermal paper is also of potential importance." accessed on May 1, 2015.
- ^ Back to school: Pollutants in pens, paints and erasers , Stiftung Warentest, September 5, 2008 (accessed online on February 26, 2013).
- ↑ wdr.de: "How dangerous are plastic pollutants?" .
- ↑ Plastics Additives By G. Pritchard (Chapter 4.13.5) at google-books
- ↑ Justin Worland, "Why 'BPA-Free' May Be Meaningless," March 16, 2015, accessed May 1, 2015.
- ^ "Bisphenol S and F: A Systematic Review and Comparison of the Hormonal Activity of Bisphenol A Substitutes" Environ Health Perspect; doi : 10.1289 / ehp.1408989 .
- ↑ BUND Online: "Phthalate Softeners", accessed on May 1, 2015.
- ↑ Phthalates - the useful plasticizers with the undesirable properties. Federal Environment Agency Berlin, February 2007.
- ↑ Umweltbundesamt, Berlin (ed.): Phthalates - the useful plasticizers with the undesirable properties. (P.10 & p.3) (PDF; 378 kB) Federal Environment Agency Berlin, February 2007.
- ↑ a b Alexander H. Tullo: Plasticizer Makers Want A Piece Of The Phthalates Pie . In: Chemical & Engineering News 93 (25), 2015, pp. 16-18.
literature
- Anonymous: Topic: Plasticizers - The soft revolution . In: Materials Science and Technology . tape 33 , no. 4 , April 2002, p. 216-219 , doi : 10.1002 / 1521-4052 (200204) 33: 4 <216 :: AID-MAWE216> 3.0.CO; 2-3 .
- Federal Environment Agency, Berlin (Ed.): Phthalates - the useful plasticizers with the undesirable properties. (PDF; 378 kB) Federal Environment Agency Berlin, February 2007.
- Regine Nagorka, André Conrad, Christiane Scheller, Bettina Süßenbach, Heinz-Jörn Moriske: Plasticizers and flame retardants in house dust. Part 1: Phthalates . In: Hazardous substances, clean air, Vol. 70, No. 3, 2010, ISSN 0949-8036 , pp. 70–76.
- Hermann Fromme, Wolfgang Körner, Ludwig Gruber, Dieter Heitmann, Martin Schlummer, Wolfgang Völkel, Gabriele Bolte: Exposure of the population to phthalates. In: Hazardous substances, clean air, Vol. 70, No. 3, 2010, ISSN 0949-8036 , pp. 77-81.
- Gerhard Volland, Thomas Gabrio, Roman Wodarz, Dagmar Hansen, Volker Mann, Sibylle Hildenbrand: Influence of di (2-ethylhexyl) phthalate (DEHP) in house dust and indoor air on daily DEHP intake. In: Hazardous substances, clean air, Vol. 70, No. 3, 2010, ISSN 0949-8036 , pp. 83-88.
Web links
- Information on plasticizers
- Medizinauskunft.de: Plasticizers make sterile ( Memento from September 5, 2011 in the Internet Archive ), March 22, 2010.
- Phthalates - What's the Problem? from: Federal Ministry for the Environment (BMU)
- [German] Federal Environment Agency for Man and the Environment: Phthalates, the useful plasticizers with their undesirable properties (PDF file, last accessed December 2012; 378 kB)
- Information, news and studies on the subject of plasticizers on the website of the environmental organization Plasticontrol e. V.