Polyvinyl chloride

polyvinyl chloride (abbreviation PVC) is an amorphous thermoplastic plastic. It is hard and brittle, from white color and only by addition by softeners and stabilizers more softly, ductile and for technical applications is suitable. Admits is PVC forwardseverything by its use in floor coverings. It plays beyond that an important role in the building industry, where it finds among other things in the form of window sections and pipes use.

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Atomic formula polyvinyl chloride.

Table of contents

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use 6 economics 7 lastingness of 8 environmental aspects 9 Web on the left of <[>work on<]> structure polyvinyl chloride. The chain extension takes place either via radical or via ionische polymerization.

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Vinyl chloride to polyvinyl chloride.


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Characteristics

Comparison parameter PVC-U (PVC hard) PVC-P (PVC softly)
mechanical characteristics:
Density in g/cm ³ 1.38-1.55 1.16-1.35
tensile strength N/mm ² DIN 53455 50-75 10-25
elongation of break/ultimate tensile strength % DIN 53455 10-50 170-400
course elastic module N/mm ² DIN 53457 1000-3500 xxx
ball pressure hardness 10-second-worth N/mm ²DIN 53456 75-155 xxx
impact strength kJ/m ² DIN 53453 > 20 o.
Notched-bar impact-strength kJ/m ² DIN 53453 2-75 o. Break.
spec. Conductance Ω DIN 53482 > 10 15 > 10 11
surface resistance Ω DIN 53482 10 13 10 11
customs temperature in °C 65-90 -
electrical characteristics:
Dielectric constant DIN 53483 50 cycles per second <math> \ epsilon_r< /math> 3,5 ,4-8
dielectric constant DIN 53483 10 6 cycles per second <math> \ epsilon_r< /math>

the hardness and tenacity of PVC can 3,0 4-4.5 by the additive of softener be varied well. It leaves itself gooddye. PVC hardly takes up water , is steady against acids, caustic solutions, alcohol, oil and gasoline. PVC von Aceton , Äther , Benzol , Chloroform , and concentrated hydrochloric acid is attacked. Hard PVC leaves itself good, to soft PVCprocess badly machine cutting. At temperatures of 120 - 150°C can be non-cutting deformed it. Connections can be manufactured with special adhesive or by welding with hot-air.

PVC burns flame with yellow, strong Russian that, and expires without further external flaming fast. Due tothe high Chlorgehalts is PVC with difficulty inflammable, contrary to other technical plastics as for example polyethylene or polypropylene, which need additives of (partly problematic) Flammhemmern for reaching this characteristic.

Like all plastics PVC a good insulator is practical. The training of dipoles and their constant reorientation in the electrical alternating current - field leads compared with most other insulators to relatively high dielectric losses. With fires poisonous hydrochloric acid steams develop. Because of that the high firmness of the sheath and thatgood insulating properties are however continued to shift PVC cables. For the transfer under finery or in the free one PVC low-voltage cables are very well suitable.

history

the French chemist Henri Victor Regnault was 1835 first, that in the Giessener laboratory of Justusfrom Liebig vinyl chloride manufactured and did not notice that from it during longer effect of sunlight a white powder - polyvinyl chloride - formed, could the meaning of its discovery however not recognize.

Also a reason for the today's employment of polyvinyl chloride is safethe use of another material and a waste problem developing from it. With the blossoming of the chemical industry the raw material caustic soda solution, which also today for many processes and procedures one uses, in ever larger quantities was manufactured. The most important areas of application thatCaustic soda solution are the processing in the soap industry, the cellulose production and the production of aluminum from bauxite. The caustic soda solution won with the help of electrolytic decomposition from common salt (sodium chloride), remaining remained thereby chlorine and hydrogen.

1912 received to thatGerman chemists Fritz Klatte of the chemical factory Griesheim, later a production place of the company most, the order, to find new conversion products for the raw material Ethin (acetylene), existing in large quantities. Also it set for its attempts, like before Regnault,Glass containers with vinyl chloride and different additives the sunlight out. Its research led 1912 to the synthesis of vinyl chloride from acetylene and hydrogen chloride. 1913 received the patent to Klatte on „the polymerization from vinyl chloride and use as horn replacement, as films, art threads and forLacquers “. It put thereby the foundation-stones for the production of PVC, which for the time being made only the connection of chlorine possible and permitted so the storage in large quantities. With the scarcity of raw materials during and after the First World War the efforts were strengthened,To use PVC as raw material, in order to replace expensive raw materials by economical materials. It came however only end of the 1920er years to further applications. 1928 took place the industrial evaluation via production in the USA and 1930 in Rheinfelden via thoseBASF; 1935 took up the industrial union colors PVC production.

1935 succeeded in bitter field the plasticizing of hard PVC at temperatures of 160 degrees Celsius: first products were foils and pipes. The latters were shifted 1935 in bitter field and salt lattice. After 1945PVC was the usually produced plastic of the world.

The development of chlorine chemistry can be attributed thus to the necessity to store those with the production of caustic soda solution by electrolytic decomposition of sodium chloride developing large quantities of chlorine and a useto supply. This became possible by the industrial and commercial development of the thermoplastic material PVC.

technology

the initially used, in the meantime historical addition process from chlorine to vinyl chloride is not so any longer used. Today crude oil becomes (or in smaller extent Coal) and further common salt as the more inexpensive raw material basis assigned. Four different polymerization procedures will be manufactured used, whereby about 80% of the entire world production developed 1935 after that , with Wacker chemistry, polymerization so mentioned in suspension using peroxides as starter molecule.Also the Emulsionspoylmerisation comes to the synthesis to the employment.

Today PVC in soft PVC becomes (PVC-P) and PVC-hard (PVC-U) partitions. A well-known representative of soft PVC is not the imitation leather (special manufacturing processes over paint from pastes), it has anything to dowith Tischdecken, Duschvorhängen, furniture foil (DC fixed, Pretty, Portas) and others, which are kalandriert. From hard PVC pipes and profiles become, z. B. for windows manufactured, and/or. Pharmacie foils (tablet packing, chocolate packing, food packing, etc.).Soft PVC contains softeners up to 40% and PVC-hard contains in principleno softener (therefore it also PVC hard).

PVC is a thermoplastic plastic, which is normally processed in the temperature range from 160 to 200 degrees Celsius. Actually brittle and hard PVC becomes with additives, primarily softeners, stabilizers and Schlagzähmodifier adapted to the most diverse operational areas. The additives improve the physical characteristics like the temperature, light and weathering, the tenacity and elasticity, the notched-bar impact-strength, the gloss and them serve the improvement of the workability. To the used PVC additives high requirements becomeplaced: They must exhibit a high effect, which may not be impaired by the different production processes for the plastic shaped part in as small a concentration as possible. They must lend during its life the desired characteristics to the shaped part. They are also from consumer view surelyapplicably its (see: Environmental aspects).

By stabilizers the processing is only made possible at temperatures between 160 and 200 degrees Celsius, since without it decomposition processes begin under splitting off from hydrogen chloride.

The additive of softeners lends from naturefrom hard material characteristics similarly those of rubber. As softeners above all Phthalsäureester are used. Adipic acid esters and phosphoric acid esters have less meaning. The softeners store themselves with the thermoplastic processing between the molecule chains PVC and loosen therebythe structure up. Since it does not concern during the storage a chemical connection, softener molecules of the surface of the PVC articles can evaporate or migrate into other materials. Softeners on the basis DOPE or similar products can migrate, it giveshowever products of other manufacturers (DSM Uraplast types) on other basis any longer do not migrate however are clearly more expensive and increasingly at least in Europe to be used.

Characteristics are improved by so-called Schlagzähmodifier like the notched-bar impact-strength. Modifier usually consist of high-efficientAcrylate polymers. In addition can be improved by Modifier the processing of PVC (effect: faster plasticizing of PVC).

use

about 70% of applications of PVC been allotted to the building sector, here is converted PVC to window sections, pipes, floor coverings or roof sheets.The pipes add themselves because of their smooth inner surface few. In addition flame resistant cables and foils are manufactured, latter z. B. for the water cores of water beds. Also to the production of imitation leather PVC is used.

PVC expanded polystyrene finds in the GRP components technology use as Sand yielding material, for example in sport boats, rotor blades for wind-powered devices and in the building of railroad cars.

The low weight of the plastic can lead to energy conservation in ranges of application such as packing (fuel economy with the distribution) and traffic ( smaller fuel consumption).

The particularly positive characteristics of PVClike acid, oil and sea water stability are not necessary with many applications. Therefore some environmental federations guess/advise to it to stop the production of PVC as soon as possible up to some few special's applications (for example gasoline tanks and - cans).

In some ranges of application also different can Plastics such as PP (polypropylene) or PE (polyethylene) instead of PVC to be inserted. In particular they do not need softeners, which from soft PVC can evaporate (typical plastic smell) and are strongly injurious to health.

economics

acquaintance trade name for hard PVCare Astralon, Luvitherm, Rhenadur, Rhenalon, Trovidur and Vinidur. Soft PVC is among other things available under the names Acella , Adretta , Alkar , Coroplast , Tautex , Koresal , Mipolam , Pegulan and Renolit.

PVC productionincreases further world-wide. To be predominantly exported windows with PVC frameworks, equally for example pipes are frequently used for cable routes and diaphragm roofs. Among them PVC is used also in the floor mat production. In Germany about 150,000 persons employed in over 5.000 enterprises gain 20Billion euro conversion. The PVC industry represents about a quarter of the plastic industry.

impact on the environment

has lastingness of products of PVC with the production, use and disposal just like other products. About PVC many controversially led debates take place,so far neither a degradation still another improvement of the environmental impact could be proven by renouncement of PVC. The Federal Office for Environment Protection comes in its lastingness - study from 1999 to the result that a substitution of hard PVC with attention of certain improvements like the introductiona missing recycling „to no substantial decrease of environmental risks “, recommends with soft PVC due to opposite different plastics the high portion partial problematic softener leads however as a possibility also an avoiding on other materials.

With a complete comparison in Ökobilanzen,including a complete recycling at the end of the Lebenszyklusses of a product, PVC products in appraisals cut off well are in particular their longevity and their comparatively low power requirement on the average with the production. All total evaluations published so far recommend however ecological improvements, above allevenly within the range of the again and/or. Far utilization.

So far the complete recycling presupposed with the total evaluations arranged by the industry does not take place however, whereby the ecological balance of PVC worsens clearly. The European PVC industry has a self obligation in March 2000for lasting development discharges. Each year is published a report over the year run off in each case.

1999 five studies were given by the European commission to the PVC disposal in order to aspects, on their basis the European Union commission in July 2000 a green bookPVC submitted. Aspects of products of PVC during the entire life cycle and economic pro and cons were analyzed not or not sufficiently. Thus it came in April 2001 with the tuning of the European parliament neither to a vote for a general renouncementon PVC still PVC products were not evaluated as „lastingly “. The self obligation of the PVC industry was evaluated as not alone sufficiently and the problematic burn or Deponierung of PVC as only „temporary solution “. A conclusion of the European Union commission from the green book debate is planned.

environmental aspects

PVC is a chemically very stable connection, which is not rotted and is not impaired also by sunlight only superficially and in the mechanical characteristics. Products and packing from PVC are (sea) water and air-steadily and thus during that Garbage mülldeponierung as far as possible groundwater and environmentalneutrally.

With the zerspanenden treatment of PVC gaseous hydrogen chloride develops.

In the case of fire among other things strongly corroding gaseous hydrogen chloride (HCl) develops, when meeting with water develops from it for hydrochloric acid with the decomposition of PVC. With PVC fires developalso Dibenzodioxine and Dibenzofurane, also dioxins and Furane mentioned, as well as, the high-poisonous , partly also carcinogenic polykondensierten aromatics such as Benz ( A) - Pyren, Pyren fixed at the soot and Chrysen. For these reasons PVC is only reduced certified as flame resistant building material in buildings andleads with fires again and again to strong environmental pollutions. A burn in an incineration plant is possible only under special conditions without environmental pollutions. Surface covering cancelling systems of the kunsstoffverarbeitenden industry exist, over by segregating the environmental damage for products of building of PVC such as pipes and windowsto reduce.

By the example PVC became for the first time the problem with the production and while handling a plastic clearly. Workers in PVC production got sick with the lung or with the joints. The so-called „VC-illness “became of the professional associations as Occupational illness recognition. Vinyl chloride can produce cancer with humans and works hereditarygood-changing.

Soft PVC is partly physiologically precarious in some areas of application by the contained softeners. The employment of soft PVC is in particular problematic for toys. The softeners can over skin contact and saliva inthe body of the children arrive. The Phthalate contained in the softeners damages liver and kidneys and stands in the suspicion to work carcinogenically. Several investigations resulted in this, in which among other things clear traces in the blood were. Diethylhexylphthalat (DEHP) became throughan European Union working group in the year 2000 as fruit-damaging and fertility-damaging estimated. Therefore soft PVC was already forbidden for the production of toy for infants in the European Union in the year 1999. Also the use of soft PVC in food packing is problematic, there the softeners inthe food to penetrate can.

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