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Uvita SME™ Spectral Modifier and Enhancer

UVITA SME ™ SPECTRALMODIFIERS AND ENHANCERS

 

A NewApproach to Ultraviolet Protection and Light Stabilization

 

UVITA SME ™and PLASMONICS

 

Ultraviolet(UV) light is part of the electromagnetic spectrum between visible light andX-rays.

 

 The whole ofthe electromagnetic spectrum is shown below.




UvitaSME™ plasmonics technology provides permanent and broadsustainable UV protection, with no migration or extraction from 200 to 800 nmand into the near to far IR. It is highly synergistic with other UV lightstabilizers, including hindered amine light stabilizers (HALS).

 

UvitaSME™ plasmonic UV protection is innovative technology in the field ofstabilization for all plastics and coatings, without the common restrictions ofred and blue shifts and hypsochromicity. Instead the presence of Uvita SME™produces a consistent hyperchromic shift with other UV light stabilizers, neverbefore seen in the history of light stabilizers.

 

Discussionson the subject of plasmonics usually concentrate on the topic of surfaceplasmons on metal nanoparticles. However, in the case of Uvita SME™,there is an electromagnetic transfer of excited electrons from the surface ofthe particle to form a plasmon cloud over the particle; transference of that energyto the conductive band of the organic UV absorbers is the cause of thehyperchromicity.

 

Allcurrent organic light stabilizers, from the class of Ultraviolet Absorbers(UVA) to Hindered Amine Light Stabilizers (HALS), have known limitations incompatibility, volatility, migration, extraction, internal mobilizationfrom layer to layer, chemical in-situ conversion over time, and blooming. Theselimitations also come with short term performance and high cost.

 

ConventionalUV absorbers differ from hindered amines in that they absorb energy in the 280to 400 nanometer region of the electromagnetic spectrum. All known classeschange in both plastics and coatings over time when exposed to light, and lose their absorbance properties.

 

Thetrend in UV absorbers today is to use more expensive cost triazine UVabsorbers, because of the limitation or elimination of hydroxy substitutedbenzotriazoles due to ECHA and REACH regulation on bioaccumulation andbiotoxicity. This has become a product stewardship issue until they aremandated out of existence, which is only a matter of time.

 

Researchand development in Plasmonics and Photonics hasresulted in the development of a new class of Uvita™ Spectral Modifiers andEnhancers (Uvita SME™). Innovative Uvita SME™ products work alone,or especiallywell in combination with organic ultraviolet absorbers, and with their  counterparts in hindered aminelight stabilizers (HALS). They do not suffer from use in hot climates and highhumidity environments, and have no restrictions in their maximum wavelengthabsorption (lambda maxima).

 

UvitaSME™ are the product of inexpensive green chemistry derived from sustainableresources. They complement all organic UVA and HALS synergistically, byincreasing the absorbance of the UVA and HALS in the polymer system, whileshowing hyperchromicity and bathochromic shifts to higher wavelengths.

 

UVITASME™, in combination with HALS and organic UVA, also slows down in-situconsumption when exposed to UV radiation. They are very cost-effective andhighly efficient in applications such as:

 

O Control of post-harvestfood packaged in plastics.

O Insect vector control during crop production.

O Permanent laminated thermoplastic films over pigmentedplastic, for decking and roofing, etc.

O Extends the protection food packaging materials and oilsbeyond the 400 nm range.

 

Verylong term to permanent broad UV protection is the key to superior performance,and Uvita SME™ technology to achieve this is available today. There are noknown limitations for the use of this technology, which has been tested incondensation polymers, PET fibers and cast films and PETG, without any adverse effects.Polyolefin blown films and thick sections have been successfully tested in avariety of polymers. One denier PET fibers with 2400 ends were producedrecently and found to have potential for military use in clothing and blanketsfor IR protection against night vision devices.

 

Recentstudies of pigmented polyolefin show that UVITA SME™ protects both mass toneand tint systems during UV exposure, even in the absence of hindered amines(HALS).  However, UVITA SME™ in combinationwith HALS significantly extends performance.

 

Insummary, any polymer requiring long term broad UV protection will benefit fromthis disruptive innovationin Uvita™ Spectral Modifiers and Enhancers technology.


Explanation of terms

 

Infrared (IR) isinvisible radiant energy, electromagnetic radiation with longer wavelengthsthan those of visible light, extending from the nominal red edge of the visiblespectrum at 700 nanometers (frequency 428.27 THz; 1.77 eV) to 1 mm (300 GHz;1.24 meV), (although people can see infrared up to at least 1050 nm in experiments).

 

Plasmon. In physics, a plasmonis a quantum of plasma oscillation. As light consists of photons, the plasma oscillationconsists of plasmons. The plasmon can be considered a quasiparticle since itarises from the quantization of plasma oscillations, just like phonons arequantizations of mechanical vibrations. Thus,plasmons are collective (adiscrete number) oscillations of the free electron gas density, for example, atoptical frequencies. Plasmons can couple with a photon to create anotherquasiparticle called a plasma polariton.

 

Bathochromic shift isa change of spectral band position in the absorption, reflectance,transmittance, or emission spectrum of a molecule to a longer wavelength (lowerfrequency). Because the red color in the visible spectrum has a longerwavelength than most other colors, this effect is also commonly called a red shift.


Hypochromicity is thedecreasing ability of a material to absorb light.


Hyperchromicity is theincreasing ability of a material to absorb light.

 

Hypsochromic shift is a change of spectral band position in theabsorption, reflectance, transmittance, or emission spectrum of a molecule to ashorter wavelength (higher frequency). Because the blue color in the visiblespectrum has a shorter wavelength than most other colors, this effect is alsocommonly called a blue shift.


The wavelength range of optical radiation

According to DIN 5031, theterm "optical radiation" refers to electromagnetic radiation in thewavelength range between 100 nm and 1 mm. The terms "light" and"visible radiation" (VIS) refer to the wavelength range between 400nm and 800 nm, which can be perceived by the human eye. Optical radiation with wavelengthsshorter than 400 nm is called ultraviolet (UV) radiation and is furthersubdivided in UV-A, UV-B and UV-C ranges. Similarly, infrared (IR) radiationcovers the wavelength range above 800 nm and is subdivided in IR-A, IR-B andIR-C ranges (DIN 5031, part 7).













This data containsgeneral information and describes typical properties only. It is offered foruse by persons qualified to determine for themselves the suitability of ourproducts for particular purposes. No guarantee is made or liability assumed,the application of this data and the products describes herein being at thesole risk of the user.


UVITA™SPECTRAL MODIFIERS AND ENHANCERS

Glass-FilledNylon 6 Molded Parts Outdoor Exposure Trials


Theimages below are of black pigmented injection molded parts made withglass-filled nylon 6, and used for the critical supportframes used in building construction in India. The hostileenvironment of heat and air pollution and acidic environment parallels that ofsummer conditions in June to August on the roofs of many industrial cities inthe southern USA.

 

Heatand light are very detrimental to black glass-filled nylon; the light factor istwice as damaging, causing surface whitening within the first six months ofexposure. Degradation occurs from the surface inward, and continues withfurther deterioration of the surface and physical properties of the moldedparts.

 

The images shown below are of samples of injectionmolded glass-filled nylon parts produced over ten years ago. Parts containingstandard UV 2700 stabilizer only are compared to parts also stabilized with ourUvita™ SME specifically designed for nylon resins. The control on the left hasUV 2700 at 0.30%, but no Uvita™ SME; the three samples to its right eachcontain 0.20%, 0.40%, and 0.80% of Uvita™ SME, and also contain UV2700 at 0.30%.



Noreal surface damage is reflected on the stabilized samples nor is there anycrazing or cracking.

Thecontrol turned white within six months on the roof and continued to losesurface weight as degradation proceeded over the years of exposure.






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