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BASF Light Stabilizers to prevent polymer degradation

Light stabilizers and UV absorbers are designed to solve the polymers degradation issues caused by exposure to sunlight. BASF has developed a comprehensive range of light stabilizers and UV absorbers to meet the requirements of various markets and applications (Agriculture, Automotive, Building & Construction and others).

Light stabilizers & UV absorbers

BASF Light Stabilizers to prevent polymer degradation

Exposure to sunlight and some artificial lights can have adverse effects on the integrity and the durability of plastics articles. UV radiation can break down the chemical bonds in a polymer. This process is called photodegradation and ultimately causes cracking, chalking, color changes and the loss of physical properties such as impact strength, tensile strength, elongation and other properties.
Figure 1: Polymer before exposure to sunlight Figure 2: Polymer after exposure to sunlight

There is one effective solution to prevent polymer from photodegradation: the use of light stabilizers.

BASF has developed a comprehensive range of light stabilizers and UV absorbers to meet the requirements of various markets and applications.

What causes polymer degradation?

Solely the UV radiation of the solar spectrum has enough energy to degrade a polymer. According to the 1st law of the photochemistry, light must be absorbed by a chemical substance in order for a photochemical reaction to take place.

The UV radiation on the globe varies with latitude, altitude and seasons as shown in Figure 3:

Figure 3: Annual UV radiation on the globe

Weathering of plastics includes, in addition to the effect of UV radiation, environmental factors like temperatures, precipitations, contaminants and others:
  • Polyolefins absorb UV light only because of impurities present in the polymer, oxidation products formed during processing or additives and pigments used in the formulation of a finished article.
  • On the other hand, other polymers like Engineering Plastics and Rubbers absorb UV-light because of their intrinsic chemical structure (e.g. Polystyrene, Polyesters, ...)

How do UV and Light stabilizers work?

To counteract these damaging effects on plastics performance, a broad range of UV stabilizers designed to solve the degradation problems associated with exposure to sunlight have been developed.
Although you can find many types of UV stabilizers, they can be categorized into two general classifications:

Ultraviolet Light Absorbers (UVA) to retard photodegradation

UVAs slow down the degradation process by preferentially absorbing harmful ultraviolet radiation and dissipating it as thermal energy.

Figure 4: UV radiation absorption

The absorption of UV Light is governed by the Law of Lambert-Beer:

Absorbance = Molar Absorptivity · Concentration · Path Length

or A = ε.c.l = log 1/T where T (transmittance) = I/Io (Io is the initial light intensity)

To obtain an optimal absorption and thus effectively retard photodegradation, it is required to have high concentrations of absorbers and sufficient polymer thickness.

UV Absorbers are therefore effective:

  • At protecting the polymer bulk
  • At protecting the content when used in packaging films or bottles
  • At protecting other additives, more sensitive to UV light (e.g. pigments and flame retardants)
  • In UV absorbing substrates, such as polystyrenes, polyesters, etc.

However, they are less effective at protecting surfaces (crazing) and very thin articles such as film/fiber.

Hindered Amine Light Stabilizers (HALS) to inhibit polymer degradation

HALS are very efficient stabilizers for polymers and especially polyolefins. They do not absorb UV radiation, but act to inhibit degradation of the polymer. Significant levels of stabilization are achieved at relatively low concentrations. HALS' high efficiency and longevity are due to a cyclic process wherein the HALS are regenerated rather than consumed during the stabilization process.

Figure 5: Cyclic process - HALS regeneration

HALS are therefore:

  • Very effective in high surface area applications such as film and fiber
  • The most effective additive for the light stabilization of polyolefins
  • Also highly effective thermal stabilizers for longer polyolefin articles service life

UVAs and HALS synergy to enhance light stability

In some applications, combinations of UVAs and HALS create a synergistic interaction that may enhance light stability of a plastic article. Other additives could also have their importance in the light stability performance of a UVA - HALS system and particularly the process stabilization package.

A variety of UV Absorbers and HALS have been developed to meet polymer and specific applications requirements. High molecular weight products were commercialized to address issues like volatility and migration of light stabilizers. The selection of the optimal UV Stabilizer will depend on the polymer type, the thickness, the use of pigments and other additives and of course the expected lifetime in a specified environment.

Browse the BASF UV & light stabilizers selector to find the most appropriate solutions according to the polymer, the application and the processing mode!

Find out how BASF UV & Light stabilizers can help you meet the needs of various markets:

       Agriculture       

HALS as HATS

Light stabilizers solutions for Agricultural films

Light stabilizers for Automotive applications

Protect Synthetic Fibers with Light stabilizers

BASF Light Stabilizer solutions for Building and Construction Applications

Synergies between Light Stabilizers and Antioxidants

Product Datasheets

Uvinul® 5050 H

Uvinul® 5050 H by BASF is a high molecular weight, oligomeric hindered amine light stabilizer (HALS). It is alpha-alkenes(C20-C24) maleic anhydride-4-amino-2,2,6,6-tetramethylpiperidine, polymer. It shows excellent polymer compatibility and good extraction resistance. It exhibits high compatibility ...

Tinuvin® XT 100 FF

Tinuvin® XT 100 FF by BASF is a high performance light stabilizer system based on high molecular weight hindered amine NOR™ light stabilizer. It is cost effective and is designed to provide stabilization to greenhouse and mulch films for a longer lifetime. It shows a good performance even in presenc...

Tinuvin® XT 55

Tinuvin® XT 55 by BASF is a hindered amine light stabilizer (HALS). It is a high-performance light stabilizer, which imparts outstanding weatherability to polyolefins. The main advantage of Tinuvin® XT 55 UV & light stabilizer is its well-balanced property profile combining light and thermal stabili...

Chimassorb® 2020

Chimassorb® 2020 by BASF is a high molecular weight hindered amine light stabilizer (HALS). Offers an optimal combination of exceptional levels of UV- and long-term thermal stability and ancillary properties such as minimal pigment interaction and improved melt flow control. Chimassorb® 2020 is a hi...

Tinuvin® 1600

Tinuvin® 1600 by BASF is 2-hydroxyphenyl-s-triazine derivative. It acts as an ultraviolet light absorber (UVA). It exhibits very low volatility, excellent thermal stability and high extinction coefficient. Tinuvin® 1600 light stabilizer allows polycarbonates, polyesters, and acrylics to achieve a hi...

Tinuvin® NOR® 371

Tinuvin® NOR® 371 by BASF is a high molecular weight hindered amine NOR stabilizer (NOR HALS). This high-performing light stabilizer is particularly well suited for applications in contact with chemicals, like in agriculture, such as greenhouse and mulch films or nonwovens. Tinuvin® NOR™ 371 provide...

Chimassorb® 81 FL

Chimassorb® 81 FL by BASF is a benzophenone grade. Acts as a UV absorber. Imparts good light stability when used in combination with hindered amine light stabilizer (HALS) of Chimassorb®, Tinuvin® or Uvinul® range. Protects a number of other polymers against degradation caused by light exposure such...

Chimassorb® 81 P

Chimassorb® 81 P by BASF is benzophenone which acts as a UV absorber. It imparts good light stability when used in combination with a hindered amine light stabilizer (HALS) of the Chimassorb®, Tinuvin® or Uvinul® range. Shows good compatibility with polyolefins and plasticized PVC. Protects a number...

Chimassorb® 944 FDL

Chimassorb® 944 FDL by BASF is a poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6 hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]). It is a high molecular weight oligomeric hindered amine light stabilizer (HALS) and heat stabilize...

Chimassorb® 944 LD

Chimassorb® 944 LD by BASF is poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6 hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]). It is a high molecular weight oligomeric hindered amine light stabilizer (HALS) and heat stabilizer. ...

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