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UV Stabilizer 101: Everything You Need to Know

uv stabilizer
Find out everything you need to know about UV stabilizers for plastic. This includes knowledge of UV tests, KLY, and products with UV stabilizers.
Table of Content

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 prevent 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.

weather test

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

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 most used UV stabilizer is HALS. The second is UV absorbers.

1) Hindered Amine Light Stabilizers (HALS)

can decompose hydroperoxide, quench excited oxygen, and capture free radicals, and the effective groups can be recycled. So its UV stabilization efficiency is 2 ~ 4 times higher than that of UV absorbers.

UV stabilizer examples of hindered amine light stabilizers: HS-944, HS-622, and HS-962(783)

2) UV absorbers

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.

UV stabilizer example of UV absorbers: UV-326, UV-531, UV-9, and UV-327

What is UV masterbatch?

The UV absorbers or hindered amine light stabilizers(HALS) is 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.

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

Kilo Langley Map
Kilo Langley Map

Table of Annual UV Irradiation Energy in Major Countries Worldwide.

Country KLY Country KLY Country KLY Country KLY
Austria 80 Germany 80 Mozambique 160 Turkey 140
Afghanistan 180 Greece 120 Netherlands 80 UK 70
Alaska 70 Guatemala 140 Nicaragua 140 Uruguay 160
Algeria 160 Guyana 120 Niger 200 United States (North) 100
Angola 120 Haiti 160 Norway 70 Arizona, US 140
Argentina 160 Honduras 140 New Zealand 120 Florida, US 140
Australian 180 Hungary 80 Oman 160 Vietnam 140
Bahamas 140 India 180 Pakistan 180 Venezuela 160
Bahrain 200 Indonesia 140 Panama 140 Zambia 180
Belgium 80 Iraq 180 Paraguay 160
Burma 120 Iran 180 Peru 140
Bolivia 140 Israel 180 Philippines 140
Brazil 120 Italy 120 Poland 80
Bulgaria 100 Jamaica 160 Portugal 140
Canada 100 Japan 100 Rumania 100
Chad 200 Jordan 180 Russia (North) 70
Chile 140 Kenya 180 Russia (South) 140
China 140 Kuwait 180 Saudi Arabia 200
Columbia 100 Korea 120 Senegal 180
Costa Rica 140 Lebanon 180 Sicily 140
Cuba 140 Luxembourg 80 Singapore 140
Cyprus 140 Libya 180 South Africa 160
Denmark 70 Madagascar 140 Spain 140
Egypt 200 Mali 200 Sudan 220
Ecuador 120 Malta 160 Surinam 120
Salvador 140 Malaysia 140 Sweden 70
Ethiopia 140 Morocco 160 Switzerland 80
Finland 70 Mauritania 180 Thailand 140
France 120 Mexico 160 Tunisia 160

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 (290-400nm). 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.

weathering test

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 ASTMG154 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.

weathering test outside
weathering test outside

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 agrotextiles

  • UV- resistant greenhouse film

  • UV – resistant mulch

  • UV – resistant silage film

Please contact EyouAgro for more information on these and other available or customized 

products.

UV stabilizer for Agricultural application:

Products Ideal for UV Stability Custom Benefits (For example, the local KLY is 140.) UV Guaranteed Years=UV Stability of Products/ Local KLY
Shade Net Used to block UV rays and visible light, reduce heat transfer, and reflect light 700kly 1400kly 5 years UV Guaranteed (7 years Life Span) 10 years UV Guaranteed (12 years Life Span)
Hail Netting The anti-hail net is used to prevent plants from being damaged by hail. 700kly 1400kly 5 years UV Guaranteed (7 years Life Span) 10 years UV Guaranteed (12 years Life Span)
Bird Netting Bird netting is used in agricultural applications to protect crops from birds and other animals. 700kly 1400kly 5 years UV Guaranteed (7 years Life Span) 10 years UV Guaranteed (12 years Life Span)
Anti-Insect Net An anti-Insect Net is a kind of net used to prevent the invasion of harmful insects. 700kly 1400kly 5 years UV Guaranteed (7 years Life Span) 10 years UV Guaranteed (12 years Life Span)
Reflective Ground Mulch Reflective Ground Mulch is a new UV-resistant agricultural film that uses UV stabilizers to reflect sunlight and prevent weeds from germinating. 500kly 3.5 years UV Guaranteed (5 years Life Span)
Weed Mat It can prevent weeds from germinating and growing, keep the ground warm, and reduce the evaporation of water. 500kly 3.5 years UV Guaranteed (5 years Life Span)
Silage Film Silage film is used to wrap the forage to ensure its nutrient content and prevent it from being exposed to air, spoilage, and mould. 150kly About 1 year UV Guaranteed (18 months Life Span)
Bale Wrap Net Bale Wrap Net is used to wrap round bales of hay. 300kly About 2 years UV Guaranteed (3 years Life Span)

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.

  • EU0020E
  • EU0050E
  • EU0070E

3 Secrets You Need to Know About UV Stabilizers

HALS can be destroyed by acids

HALS is generally a weakly alkaline chemical and 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.

Colouring agents can affect the effectiveness of HALS

Some pigments can weaken the UV resistance of HALS. 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

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.

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.

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.

Hey, I’m Kevin Lyu, the founder of eyouagro.com , Family-run business
An expert of agriculture protection textile specialist .
In the past 26 years, we have helped 55 countries and 150+ Clients like farms, orchards , vineyards to protect their plants. The purpose of this article is to share with the knowledge related to agriculture growing protection for making the plant healthier and stronger.
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Kevin Lyu
Agrotextile Specialists

Hey, I’m the author of this post,
In the past 26 years, we have helped 55 countries and 150+ Clients like farms, orchards, and vineyards to protect their plants and crops. 
If you have any problems with it,
call us for a free, no-obligation quote
or discuss your solution.

We are at your disposal for any technical or commercial information

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