Thermal properties Heat flows across temperature differences. There are three modes of heat transfer: conduction, radiation, and convection. Conduction and radiation are fundamental physical mechanisms, while convection is really conduction as affected by fluid flow. Conduction is an exchange of energy by direct interaction between molecules of a substance containing temperature differences. …
Silicone resins are increasingly present in our daily lives: the excellent physical and chemical properties that they have demonstrated and an eager market for new products, are promoting the progressive substitution of materials in favour of these polymers silica-based and organic radicals. We can find them in sectors where they are already a classic, such as the artistic sector (masks, makeup), cosmetics, kitchen objects, toys (of all kinds), etc. and in the most innovative such as electronics, robotics, engineering …
The reason is clear: the development of new materials has begun just a few decades ago and the reality is that, although with the polymers an important effort has been made in the development of plastic materials, with the silicones it has not occurred: we are facing a development field with a lot of potentials and little “exploitation”. One of the reasons is the small number of specialists for the development of new and formulated polymers, as well as the lack of knowledge of the underlying chemistry.
However, it has its advantages: being a “relatively” new chemistry implies that it is already going to comply with many regulations, both current and given, since the developments already seek to avoid the presence of harmful pollutants for both people and the environment With what, predictably, this industry will be able to face the challenges of the future with more guarantees than others that “drag” the presence of heavy metals, CMR substances (carcinogenic, mutagenic or that affect reproduction), bioaccumulative substances, etc.
The first regulation that silicone must compliance in Europe is REACH (Registration, Evaluation, Authorization and Restriction of Chemicals. More information at (https://echa.europa.eu/es/regulations/reach/understanding-reach), regulations that seek to protect human health and the environment while promoting the substitution of the hazardous chemicals currently used.
Commercial silicones are polymers that have been generated from substances, our formulations may contain different additives to provide properties to the final formulation. And here the challenge begins: knowing which components must be registered according to REACH1 regulations and protocols not. Likewise, it is necessary to identify which position is occupied in the logistics chain2 to know what obligations must be fulfilled3.
- REACH regulations take into account: substances, mixtures and articles. Substances are chemical substances that may contain other materials in a minority but cannot be separated. The mixtures are mixed more than one substance or other mixtures. Items are objects, formulated, etc. Resulting from the mixtures and having use or application by the end-users.
- At the base of the chain is the manufacturer or importer of substances. Once the substance is in Europe, all derivative operations will be carried out by intermediate users (sale and distribution of substances, manufacture of mixtures and their load, manufacture of articles and their load, etc.). At the end of the chain are the end-users, who will be the users of the articles.
- Mainly information actions, which will go from the manufacturer/importer to the end-user (downstream) or from the end-user to the manufacturer/importer (upstream). The intermediate user must always have all the updated information.
In the case of bi-component silicones, they are formulations containing various substances and polymers1 that form mixtures. In this case, those responsible for the REACH registration of substances and/or polymer monomers are the companies that manufacture/import chemical substances or their formulations. The companies that use these silicones for manufacturers of electronic components are intermediate users, so they are not responsible for performing registration processes.
- Polymers according to the definition of REACH regulations, are exempt from registration, but not their monomers.
But whatever the level, it is mandatory to have the chemical safety information, as well as the potential presence (or not) of especially dangerous substances, such as those listed in the SVHC (Substances of Very High Concern) listing that we can find on the ECHA website (https://echa.europa.eu/en/candidate-list-table) since it is mandatory to have this information in the final articles. In this case, the information will travel in the direction “Downstream” (manufacturer/import of substances to article manufacturer), substances that are sometimes restricted (https://echa.europa.eu/es/substances-restricted-under-reach) and are listed in annexe XVII of the REACH regulations or those that regulate (https://echa.europa.eu/es/authorisation-list) that we can find in annexe XIV of the aforementioned regulations.
It is how the Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006. It is the regulation that governs the classification of the safety of chemical substances with all the legal implications that it has. Therefore, whatever the chemical is, it must comply with these regulations: it is the one that guarantees that a chemical is specifically classified.
This regulation is directly linked to REACH since the first step in the classification of a chemical substance is the result of the mandatory physical-chemical, toxicological and environmental studies required to register it in accordance with REACH. It is from the classification of the substances that the classifications of the mixtures are developed, always in accordance with an adequate “Downstream” communication.
It is under these regulations that the Safety Data Sheets of the mixtures must be developed, with their subsequent modifications. In this way, the information to be transmitted in this security document is standardized and the quality of the information is guaranteed…
It is the initials of “Restriction of hazardous substances”, and is related to the Directive 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the restriction of the use of certain hazardous substances in electrical and electronic equipment 2, an essential requirement for the CE marking of electronic and electrical devices and their corresponding specifically. Although the CE Marking is a policy whose objective is the prevention of accidents during use, it also ensures other risks to which the user may be exposed.
Although this regulation affects electrical/electronic devices, that is, the final article, it is foreseeable that intermediate users ask for information about it. It is mainly the heavy metal content of silicones defined in Annex II of Directive 2011/65 / EU3. With this information, you can see the compliance of the different components of the device and, in summary, the compliance of the device that must exceed the CE Mark.
The variety of regulations that can affect a chemical is directly related to its applications. The control required for an application in toys will not be the same as with the application in a car or for food contact. European legislation has developed specific regulations that must be complied with without prejudice to the fact that the same substance must comply with the aforementioned regulations.
The application in toys is one of the ones that pose the most restrictions on electronic devices. The reason is to ensure the safety of children who, by definition, are more vulnerable to toxic chemicals and their imagination facilitates non-obvious routes of exposure. We must anticipate that they can touch, lick, bite, smell, eat, etc. The toy and also, many times. That is why CMR substances (Carcinogenic, Mutagenic, Toxic for reproduction) are prohibited, as well as monitoring the presence of heavy metals. The regulation that regulates the maximum limits of contaminants in toys is Directive 2009/48/EC of the European Parliament and of the Council of 18 June 2009 on the safety of toys4 (https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32009L0048). To verify that the level of heavy metals is within the established limits, tests are carried out in accordance with the UNE-EN 71-3:2013+A2:2018 Safety of toys – Part 3: Migration of certain elements.
Los vehículos son artículos que acabarán en el desguace. Esto tiene fuertes implicaciones medio ambientales debido a la gran cantidad de materiales distintos que lleva un coche y el elevado potencial de contaminación que puede contener. Para ello se desarrolló la Directive 2000/53/EC of the European Parliament and of the Council of 18 September 2000 on end-of life vehicles – Commission Statements5. This regulation does not affect the raw materials that make up the vehicle since this regulation affects the vehicle once finished, the article. That is why the chemical mixtures that are used for the manufacture of electrical and electronic devices for cars are not contemplated, without prejudice that they are materials with a low concentration of heavy metals, so that their pollution potential will be low.
There are electronic devices that use the so-called “Blood Minerals or Conflict Minerals” for their operation and their use is regulated, in Europe6. We are talking about: tin, tantalum, tungsten and gold. This defines why their exploitation is related to the illegal financing of areas of armed conflict, child exploitation, and other human rights abuses. Although they have become sadly famous for their use in devices such as mobile phones or smartphones, silicone components do not contain these metals, so they are not involved in the extraction of conflict minerals.
The European Union is working to develop its regulations that ensure that metal importers use legal sources of these metals, breaking the relationship between sources of illegal exploitation and metal trafficking that will enter into force in 2021.
There are countries like the United Kingdom that have their regulations fully developed in this regard.
The Proposition 65 List
The Proposition Lists 657 is a California regulation whose objective is to ensure that there are no very dangerous substances in chemicals. It is a list of CMR substances (carcinogenic, mutagenic and toxic for reproduction) very popular. It was developed in 1965 in this country of the United States to protect the population.
Ask if a substance or mixture contains any component listed in it is common when you expect to export a product (article, mixture) to the United States.
By their nature, silicone components are not expected to be listed.
Ensuring the safety of chemical products in their different applications is a responsibility of the manufacturers, which they comply with through adequate communication. This allows obtaining safe, environmentally friendly and sustainable items.
- https://echa.europa.eu/es/regulations/reach/understanding-reach. Information about REACH.
- https://ec.europa.eu/environment/waste/rohs_eee/legis_en.htm. Information about RoHS.
- https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02011L0065-20171211. Consolidated Directive 2011/65/EU.
- https://eur-lex.europa.eu/legal-content/ES/TXT/?uri=CELEX%3A32009L0048. Directive safety of toys.
- https://eur-lex.europa.eu/legal-content/ES/TXT/PDF/?uri=CELEX:02000L0053-20130611&qid=1405610569066&from=EN. Vehicles end-life directive.
- https://ec.europa.eu/trade/policy/in-focus/conflict-minerals-regulation/regulation-explained/. Conflict Minerals.
- https://oehha.ca.gov/proposition-65/proposition-65-list. Proposition List 65.
Embedding processes of electronic devices Long-term ,reliable protection of sensitive electronic components is essential to many electronic applications today and prevents premature failure. Increasingly small systems and rising circuit densities have resulted in hotter operating temperatures, and driven demand for high-performance solutions for heat dissipation. Potting process (1) Methods of Embedding The …
Resins are used in a lot of formulations of Coatings, Inks, Paints, and dispersions of fillers, quartz, pigments that have functional application. As a definition of resin: A thick, sticky substance that is produced by some trees and that becomes yellow and hard after it is collected, or any of various similar substances produced by a chemical process for use in industry: Or any of various solid or semisolid amorphous fusible flammable natural …
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