UV Stabilizer 101: Everything You Need to Know

Introduction

Steven, an Australian farmer, recently came across something that really bothered him. A new batch of shade netting he had purchased for his grape farm had torn and broken after only a few months of use. This caused him a great deal of trouble. Not only did he have to replace the netting, but his grape crop was also damaged.

When Steven made some inquiries, he found out that the UV stabilizer in the netting had degraded, causing it to break down. UV stabilizers are added to materials to protect them from ultraviolet radiation. This type of radiation is found in sunlight and can cause the chemical structure of materials to break down over time by photo-oxidation. UV stabilizers work by absorbing, reflecting, or scattering UV radiation and preventing photo-oxidation.

There are many different types of UV stabilizers, each with its own set of benefits and drawbacks. In this article, we’ll take a closer look at UV stabilizers, their formulations, how they’re tested, and their uses.

UV stabilizer is used in a wide range of applications and our article would only focus on their use in agriculture, including agro textiles (shade net, hail net), greenhouse film, mulch, and silage film.

Effect of UV Light on Plastic

When exposed to strong sunlight, the polymer is attacked and this procedure would produce free radicals, resulting in a series of chemical reactions. Ultraviolet light causes the plastic to break down in a process called UV degradation. UV degradation causes materials damaged by photo degradation and become brittle, discolored, and weak. In some cases, photo oxidation can also cause materials to release harmful chemicals into the environment.

UV degradation is a major problem for farmers because it can damage crops and equipment. UV stabilizers can help prevent this damage by absorbing, reflecting, or scattering ultraviolet light.

UV stabilizers are added to plastic during the manufacturing process.

What Is a UV Stabilizer? (Kilo Langley Definition)

UV Stabilizers are chemical compounds used to prevent a chemical process referred to improve polymers’ resistance to degradation caused by the photo-oxidation process. As polymers consist of chains of repeating units, sunlight can break them down.
Eventually, the plastic becomes brittle and crumbles apart due to the breakdown process.

UV stabilizers work by absorbing or reflecting the UV rays, thus preventing them from reaching the material and causing damage. This can help to extend the life and maintain the integrity of the material, making it more durable and resistant to the effects of UV exposure.

UV stabilizers are added to materials such as plastics, rubbers, and textiles to help extend their lifespan and protect plastic products.

4 Types of UV Stabilizers for Polymers

Generally, they can be divided into four categories by the principle of action:

1) Light shielding agents,
2) UV absorbers,
3) Quenchers, and
4) Free radical trapping agents (hindered amine light stabilizers, HALS or HAS).

Currently, the UV stabilizer we use mainly refers to HALS, UV absorbers and antioxidants.

Here we will talk about these three substances in detail：

1) Hindered Amine Light Stabilizers （HALS）

Hindered amine light stabilizers (HALS) are a type of organic chemical compound that is used as a light stabilizer in polymers and coatings. HALS acts as a protective agent against the damaging effects of ultraviolet (UV) light on materials, helping to prevent fading, discoloration, and degradation.

One of the key features of HALS is that they do not absorb UV light themselves, but instead act by scavenging free radicals that are generated by the UV light exposure. This allows them to provide long-term protection without affecting the optical properties of the material.

HALS are also highly effective at low concentrations and are not known to cause any adverse effects on human health or the environment. They are commonly used in a wide range of applications, including coatings for automotive and aerospace components, outdoor furniture, and building materials.

HALS is usually reflected in the mechanical properties, strength, tensile strength, and elongation, which we usually say is how many years of use, is its role of protection.

So its UV stabilization efficiency is 2 ~ 4 times higher than that of UV absorbers.

UV stabilizer examples of hindered amine light stabilizers: Chimassorb 944FDL, Tinuvin 622LD, and Tinuvin 783FDL

2) UV absorbers

UV absorbers are chemicals that are added to materials such as plastics, coatings, and other products to absorb ultraviolet (UV) radiation from the sun.
UV absorbers use the hydroxyl group, which can absorb ultraviolet rays for molecular rearrangement, to convert the absorbed ultraviolet rays into harmless heat energy, achieving a stable effect.
This helps to protect the materials from UV damage and degradation, which can cause fading, discoloration, and other issues. UV absorbers are commonly used in products such as sunscreen, clothing, automotive paint, and building materials.

UV absorbers are mainly for the protection of color vibrancy, and overall, it is a small contributor to UV stabilizers.

UV stabilizer example of UV absorbers: Chimassorb 81、Tiuvin 326、Tinuvin 328、Tinuvin 329、Tinuvin 1577 and so on

3) Antioxidants

Plastic antioxidants are chemicals added to plastic materials during the manufacturing process to prevent or slow down the degradation of plastic due to exposure to environmental factors such as UV radiation, heat, and oxygen. These antioxidants help to extend the lifespan of the plastic and maintain its physical and mechanical properties.

Commonly used antioxidants,
we are divided into the main antioxidant and auxiliary antioxidants.
The main antioxidant is to protect the finished plastic in outdoors by high temperature oxidation, typical models such as Irganox1010. Irganox1076

Auxiliary antioxidants mainly play a UV stabilizer production link, because the feeding time due to the screw high temperature and high heat will lead to high temperature degradation of resin materials, reducing the strength. To play a protective role in processing. Typical model: Irgafos168

What is UV masterbatch？

The UV absorbers or hindered amine light stabilizers（HALS）and antioxidants are added to the polymer carrier in a certain ratio according to the desired UV protection effect, and then extruded and granulated into pellets at a high temperature. After cooling and packaging, it becomes UV-resistant. The masterbatch is also called “UV pellet”.

Why make a UV stabilizer masterbatch?

We often make UV stabilizers and antioxidants into masterbatches before adding them to plastic particles in the production of plastic products.

There is a reason for this.

1. Good dispersion improves the processing performance
   When the melting point of UV stabilizers and antioxidants is more than one hundred degrees lower than the processing melting point of plastics, it causes uneven distribution of antioxidants and light stabilizers during processing and affects the processing yield.
   If it is not made into UV masterbatch, it will lead to poor dispersion and inaccurate content. It is also not environmentally friendly and will generate dust.
2. Rigorous testing
   The anti-aging masterbatch is a compound of various HALS and UV stabilizers and Oxidants, which is much more effective than single UV additives, and it is a product that has passed the QUV accelerated aging test (ASTM G154-06 Test) and outdoor exposure test, and has reached the outdoor service life before production, rather than a simple mixture of several additives granulation.

Therefore, UV stabilizers and antioxidants must be made into masterbatches.

If you would like to learn more about this, check out this article.

What are KLY in UV and its application?

UV intensity is measured in KLY (kilo langley), which is the amount of UV energy that falls on one square meter per year.

• KLY=41.84*10⁶J/m²=41.84MJ

• 1Kwh/m²⁼3.6MJ/m²

There is also a special KLY UV map, which allows you to look up the corresponding KLY values according to your location.

Table of Annual UV Irradiation Energy in Major Countries Worldwide.

Each region has a different KLY value depending on the amount of UV radiation.

Products life span and KLY

The service life of plastic products can also be estimated based on local KLY values.

After a given period of KLY values, a product should have a retention strength of at least 50%.

For example, we produce orchard netting (UV stability 700 KLY) for some vineyard farms.

In California, USA (where the KLY value is about 160), these nets last for about 4+ years before losing 50% of their mechanical properties.

In Spain (local KLY value 120), these nets will last for more than 5 years with 50% of their mechanical properties still remaining after four years.

UV Stabilization Experiment

UV radiation stability test is an important indicator to determine the ability of UV stabilizers to resist UV light. It is also the best way to test the life span of a product.

The following methods are commonly used in our lab:

Accelerated Aging Test

UV aging test is carried out in a special UV aging chamber. The UV light source is an artificial light source, and the UV wavelength is close to the UV wavelength in sunlight (280-400nm). The UV dose can be increased by using a high-intensity UV lamp or increasing the distance between the specimen and the UV light source.

1) QUV Accelerated Weathering Test

QUV accelerated aging test is a method of simulating the UV degradation of materials in a short time. The samples are placed in a special UV device, and UV lamps emit UV light with different wavelengths to the samples at a certain temperature and humidity.

After a period of irradiation, the physical and mechanical changes of the samples are observed and recorded.

The most commonly used UV accelerated aging instruments are the UVA 340 and UVB 313.

2) Xenon Arc Accelerated Weathering Test

The Xenon Arc Accelerated Weathering Test is a UV aging test that uses a xenon arc lamp to irradiate the specimen. The UV spectrum of a xenon arc lamp is similar to that of sunlight, so it is also called an artificial sunlight UV device.

3)The commonly used standard is ASTM G154-06 and ISO4892.

Exposure to Outdoor Test

The samples are placed in a natural environment with certain conditions. A light and oxygen aging test in the natural environment is carried out. This test is used to evaluate the stabilizing effect of antioxidants and light stabilizers on plastic materials during use in the natural environment.

EyouAgro’s outdoor experiments were carried out in Yunnan Province, China, where the hot climate and abundant light (KLY around 160) allowed us to obtain the precise and fast results we needed.

Rigorous laboratory tests and outdoor tests give us accurate product data and guarantee the quality and service life of our products.

UV Stabilizers in Agricultural Plastics

UV stabilizers are used in agricultural plastics to prolong the service life of products and improve their performance.

UV-resistant agrotextiles and films are widely used in agriculture, horticulture, and animal husbandry. They can be used as anti-hail nets, windbreak nets, shade nets, insect-proof nets, reflective ground mulch, silage film, etc.

UV-resistant nets and films have the following advantages:

1) They can block UV rays and visible light, reduce heat transfer, and reflect light.
2) They can prevent plants from being burned by UV rays, reduce plant evaporation, and improve plant photosynthesis.
3) They can keep the ground warm and prevent the growth of weeds.
4) They can increase crop yields, improve crop quality, and extend the growing season.
5) UV-resistant nets and films are durable and have a long service life.

The UV stabilizers used in agricultural plastics are generally non-toxic, safe, and environmentally friendly. They can be used in contact with food and have no adverse effect on human health.

EyouAgro uses UV stabilizers in agricultural plastics to ensure the safety and quality of our products.

EyouAgro can offer the following products:

• UV-resistant shading net UV-resistant insect proof net UV-resistant hail proof net
• UV-resistant anti-bird net UV-resistant grass proof cloth UV-resistant round bale netwrap
• UV-resistant straw baling rope UV-resistant cold proof non woven fabric
• UV-resistant container bag UV-resistant rattan outdoor furniture
• UV-resistant artificial grass UV-resistant simulated plant
• UV-resistant PP trampoline UV-resistant TPO waterproof roll

In a word , we can support different kinds of anti UV masterbatches to PE or PP outdoor plastics.

Please contact EyouAgro for more information on these and other available or customized UV Stabilizer products.

UV stabilizer for Agricultural application:

• UV-resistant shading net UV-resistant insect proof net UV-resistant hail proof net
• UV-resistant anti-bird net UV-resistant grass proof cloth UV-resistant round bale netwrap
• UV-resistant straw baling rope UV-resistant cold proof non woven fabric
• UV-resistant container bag UV-resistant rattan outdoor furniture
• UV-resistant artificial grass UV-resistant simulated plant
• UV-resistant PP trampoline UV-resistant TPO waterproof roll

In a word , we can support different kinds of anti UV masterbatches to PE or PP outdoor plastics.

UV stabilizer Masterbatches Products from EyouAgro

In addition to our business in agricultural applications,

EyouAgro can also, provide you with high-quality masterbatches of UV stabilizers.

• T-0020E： Suitable for KLY120-130 area, 5 Years UV guarantee
  • ( Mainly used in polyethylene, such as PE rattan, shade net, simulation plants, etc.)
• UT-0070E: Suitable for KLY140~150 area, 5 Years UV guarantee.
• UT-004: Suitable for KLY150~200 area, 5~8 Years UV guarantee.
• US-001A :
  • Mainly used in PP spunbond nonwoven fabrics: such as cold-proof cloth, grass-proof cloth, etc.

3 Secrets You Need to Know About UV Stabilizers

HALS can be destroyed by acids

HALS is generally a weakly alkaline chemical.
HALS (hindered amine light stabilizers) can be destroyed by acids.
These molecules are sensitive to acidic conditions and can break down when exposed to strong acids. This can cause the HALS to lose its effectiveness as a stabilizer, reducing its ability to protect materials from degradation due to light exposure.
It is important to avoid exposing HALS to acidic conditions to maintain its stability and effectiveness.

if the formulation contains acidic other additives will have an effect on the light stabilizer.
Therefore it is important to avoid acidic substances in the formulation or exposure to acidic substances during use. （Stay away from substances containing sulfur and chlorine）

Colouring agents can affect the effectiveness of HALS

Some pigments can weaken the UV resistance of HALS.

the addition of certain coloring agents can potentially affect the effectiveness of HALS (hindered amine light stabilizers) by disrupting the chemical structure of the HALS molecules and reducing their ability to absorb and dissipate UV light.
This can lead to a decrease in their protective effects on the materials they are added to. It is important to carefully select and test the compatibility of coloring agents with HALS in order to maintain their effectiveness.

For example,
in polypropylene, the azo-condensation pigment Red 144 and azo-condensation pigment Yellow 94 can interact with HALS, reducing their effectiveness by 25% and 50% respectively.

Pay attention to the amount of UV stabilizer required by law

Antioxidants and light stabilizers should be non-toxic and non-harmful to humans, animals, and the environment. This is also strictly regulated by national legislation.

For example,
UV326 is considered to be a non-toxic chemical. However, the EC Commission still stipulates that the maximum amount it can be used in food contact is no more than 0.5% in PP and PE, 0.3% in PVC, and 0.6% in PS.

FAQs

1. Difference between UV absorbers vs light stabilizers？

Some people have questions about these two things, so are they the same thing?

In fact, the light stabilizer is what we call a UV stabilizer.

The UV absorber is a type of UV stabilizer that works by absorbing UV light.

UV absorbers are chemicals that are added to materials to absorb ultraviolet (UV) radiation and prevent it from damaging the material. This can help prevent the material from fading, discoloring, or breaking down due to exposure to sunlight.

Light stabilizers, on the other hand, are chemicals that are added to materials to prevent the material from degrading when exposed to light. These chemicals work by scavenging free radicals and other reactive species that are generated by light and preventing them from reacting with the material and causing damage.

The main difference between UV absorbers and light stabilizers is that UV absorbers absorb UV radiation and prevent it from reaching the material, whereas light stabilizers work by scavenging reactive species generated by light and preventing them from causing damage to the material.

2. Difference between UV stabilized vs UV resistant？

They mean essentially the same thing.

When UV stabilizers are added to products, they are less likely to receive damage from UV light.
This results in UV stability （UV stabilized） or UV resistance.

UV stabilized means that a material has been treated to resist fading or degradation due to exposure to ultraviolet light. This treatment can include the use of UV inhibitors or other chemicals to protect the material from the damaging effects of UV radiation.

UV resistance, on the other hand, refers to a material’s inherent ability to resist UV damage without the need for additional treatment or protection. This means that the material itself has a natural resistance to UV radiation and will not fade or degrade over time when exposed to UV light.

Conclusion

UV stabilizers are additives that absorb UV light and convert it into heat, preventing the UV light from causing damage to the polymer. UV stabilizers are used in a variety of products, including those exposed to sunlight or artificial UV light.

There are many types of UV stabilizers, each with its own advantages and disadvantages. The type of UV stabilizer used depends on the application and the specific requirements of the product.

EyouAgro is a leading supplier of agricultural textiles, films, and UV stabilizers for agricultural plastics. We offer a variety of UV stabilizers, each with its own unique set of properties. Our products are of the highest quality and have been tested to meet international standards.

Please contact us for more information on our products and how to purchase them.

Thank you for reading this article.

We hope you have learned something new about UV stabilizers and their uses.

If you have any questions, please feel free to contact us.