Plasticizer

Plasticizers (or softeners ) are substances which are added in large scale plastics, paints and coatings, rubber, adhesives and Befilmungsüberzügen to make them softer, more flexible, more supple and elastic in use or further processing. Softeners are among the best-selling chemicals. For plastic products, around 87 % of the consumed worldwide plasticizer were used in 2012, with the largest portion flows into the production of films and cables.

You can, for example, low-volatile esters, fatty oils, soft resins or camphor be.

The plasticizer moves the thermoplastic region towards lower temperatures, ie in the area so that the use temperature of the plastic, the desired " elastic " properties.

Methods and Examples

Examples of plasticizers, which are added to plastics:

External plasticization

In the external plasticization of the plasticizer is non-covalently incorporated into the polymer, but occurs only on its polar groups to the polymer to interact, thereby increasing chain mobility.

• Phthalate (DEHP ) is used as a plasticizer for PVC and elastomers, and is still the most used by far plasticizer. Due to a number of negative assessments ( classified as teratogenic and toxic effects upon, among other things an EU working group in 2000) omitted the European plastics industry largely on phthalates in toys for toddlers. DEHP has also been found in olive oil. Another, more common colloquial term for DEHP is dioctyl phthalate (DOP). DEHP belongs to the group of the phthalic esters.
• Mesamoll, an alkylsulfonic acid esters of phenol ( ASE), a plasticizer for PVC, serves as a substitute for DEHP.
• Hexamoll DINCH is another substitute for DEHP and used since 2006 for the manufacture of plastic articles sensitive applications such as children 's toys made from PVC, medical products and food packaging.
• Citric acid -based plasticizers such as triethyl citrate are more expensive than phthalate -based plasticizers but they are hardly toxic and have no hormone -like effects.
• Adipic acid -based plasticizers, especially diethylhexyladipate and Diethyloctyladipat be used similar to citratbasierte plasticizer. Also, although they are toxicologically safe as phthalates, but also more expensive.

Internal plasticization

In addition to these, referred to as external plasticization methods, the so-called internal plasticization exists. In this case, the softener is introduced during a copolymerization. In contrast to external plasticization, wherein the plasticizer is linked only dipole interactions with the macromolecules, it is for internal plasticization portion of the macromolecule ( in the case of a copolymer ). Characterized the plastic is durable and soft, it has not come to a diffusing of the plasticizer. For example, vinyl chloride with up to 20 percent vinyl acetate is polymerized. Other additives for the copolymerization of vinyl chloride, maleic acid, ethylene, methyl vinyl ether or acrylic acid methyl ester.

Extender

Extenders are secondary plasticizers, which have a moderate polarity and are therefore used only in conjunction with the actual plasticizers. They are used to improve the processing and to reduce the cost of the plastic molding compound.

Plasticizer in the industry tablets

For the preparation of coated tablets by means of polymer solutions or polymer dispersions of plasticizers. These are often are low molecular weight, high-boiling liquids, such as dibutyl sebacate with a boiling point of 343 ° C. The aim is to reduce the brittleness of the coating and increase the flexibility. In addition, the minimum film-forming temperature is reduced by softening. This should ideally be at room temperature. Plasticizers overlap between polymer chains and thus increase the flexibility and elasticity of the chains. Reduce the brittleness and lower in relation to the polymer solutions for coatings having a minimum film-forming temperature.

Health effects and consequences

A general statement about the impact of " plasticizers " is so far not possible, because depending on the application, different groups of chemicals are referred to as such. In the criticism focuses mainly on plasticizers for intrinsically brittle plastics.

Certain plasticizers based on phthalates can cause infertility in men, as they are similar to certain hormones in their effect. They affect the testosterone - driven development stages. In addition, they are suspected to cause diabetes. Also been necessary as the added antioxidant - so socialized so - Bisphenol A is suspected to show health effects.

Phthalate were banned by the European Union for children's toys, but have been detected in many crayons. This is dangerous in the long run for children because they may be affected in health by chewing on painted surfaces.

In German kindergartens high loads with different plasticizers such as in an average German household were found in the middle three times. This is questionable, because plasticizers are suspected to affect the hormonal balance. Especially for children and fetuses in the womb that is dangerous: infertility, liver damage or behavioral disorders might be caused or promoted.

Alternatives to plasticizers from the group of phthalates can only be used at the same time re-optimization of physical and chemical properties, a simple exchange of substance does not exist.

Occurrence and policy

While polyethylene and polypropylene usually do not contain plasticizers, plasticized PVC is always partially of plasticizers (typically 30 to 35%). Plasticizers include in children's toys made ​​from PVC and often found in toys from the Far East. When buying such products should check for the label are " softeners / phthalates " and " BPA- free" aware of, as they are not yet banned in the EU. However, " BPA-free " is not equal bisphenol - free, because instead of bisphenol A is often used simply another bisphenol, which must not be declared. By the end of 1999, the EU had issued for toddler toys, taken as intended in the mouth, a term of three months the prohibition of certain plasticizers. This temporary measure has always been extended until today to three months. The use of phthalates were banned because there was no reliable test method to measure the migration of phthalates and thus the potential exposure of children. Today, one validated by the European Chemicals Bureau ECB method.

The global volume of plasticizers in 2004 was 5.5 million tonnes, representing a total value of around EUR 7 billion.