Weathering test of hot melt wire: a key link to ensure quality

Weathering test of hot melt wire: a key link to ensure quality

In today’s global business environment, hot melt wire, as an important industrial material, is widely used in many fields such as textiles, 3D printing, composite materials, etc. For international wholesale buyers, it is crucial to ensure that hot melt wire has excellent weathering resistance, because this is directly related to the quality and service life of the product. This article will explore the weathering test of hot melt wire in depth, including its importance, test methods, relevant standards, and precautions in practical applications, etc., aiming to provide comprehensive and professional knowledge for the majority of buyers to help everyone better choose and use hot melt wire products.

1. The importance of weathering test of hot melt wire
Thermal melt wire usually needs to be used in various complex environmental conditions, such as high temperature, low temperature, ultraviolet radiation, humidity, etc. outdoors. These environmental factors will have different degrees of impact on the performance of hot melt wire. If its weathering resistance is insufficient, it may cause the following problems:
Performance degradation: Under the long-term action of harsh environment, the key properties of hot melt wire such as bonding strength and flexibility will gradually decrease, thus affecting the overall quality and stability of the product. For example, in outdoor textiles, if the weather resistance of the hot melt is poor, after a period of exposure to the sun and rain, the bonding may crack and fall off, shortening the service life of the product.
Impact on product appearance: Environmental factors such as ultraviolet radiation may cause the hot melt to discolor and age, thereby affecting the appearance quality of the product and reducing the market competitiveness of the product. For example, in some fabric composite products with high color requirements, hot melts with poor weather resistance will cause color difference or mottled fabric surface, affecting the visual effect of the product.
Safety hazards: In some special application fields, such as automobile manufacturing, aerospace, etc., the performance degradation of hot melts may bring safety hazards. If the hot melt is not firmly bonded in high temperature, humidity and other environments, it may cause the parts to loosen or fall off, affecting the normal operation of the equipment, and even causing safety accidents.

2. Main methods for testing the weather resistance of thermal fuses
In order to accurately evaluate the weather resistance of thermal fuses, researchers and companies have adopted a series of professional testing methods. The following are some common testing methods:
(I) UV irradiation test
Ultraviolet rays are one of the important factors that cause material aging. By simulating ultraviolet irradiation in the natural environment, the performance changes of thermal fuses under long-term lighting conditions can be quickly evaluated. Usually, a UV aging test chamber is used for testing. The thermal fuse sample is placed in the test chamber, and specific parameters such as ultraviolet intensity, temperature and time are set. After a period of irradiation, the appearance changes of the sample, such as discoloration and cracking, are observed, and its physical properties, such as tensile strength and elongation at break, are tested to determine its UV resistance. For example, some high-quality thermal fuses have no obvious changes in appearance after hundreds of hours of ultraviolet irradiation, and the decline in physical properties is small, indicating that they have good UV resistance and weather resistance.
(II) Temperature cycle test
The temperature cycle test is mainly used to simulate the use of thermal fuses in different temperature environments and evaluate their stability and reliability under alternating hot and cold conditions. Place the hot melt sample in a temperature cycle test chamber and perform multiple cycle tests according to the set high and low temperature conditions, such as a cycle from -40℃ to 80℃, with each temperature stage maintained for a certain period of time. During the test, observe whether the sample cracks, falls off, or changes in bonding performance. If the hot melt shows good adaptability in the temperature cycle test and there is no obvious performance degradation, it means that it can adapt to various temperature changes in actual applications and has good weather resistance.
(III) Damp heat test
Damp heat test is an important method to evaluate the durability of hot melt in high temperature and high humidity environments. In the damp heat test chamber, set high temperature and high humidity conditions, such as temperature 40℃ and relative humidity 90% – 95%, and expose the hot melt sample to such an environment for a period of time, usually hundreds of hours or even thousands of hours. After the test, check the appearance, dimensional stability, and bonding performance of the sample. If the hot melt does not show problems such as hygroscopic expansion, mildew, and decreased bonding strength in the damp heat test, it means that it has good damp heat resistance and can be used stably for a long time in a humid environment.
(IV) Salt spray test
For some applications in coastal areas or in frequent contact with salt spray environments, salt spray testing is essential. Hang the thermal fuse sample in a salt spray test chamber to expose the sample surface to a salt spray environment of a specific concentration. Generally, a 5% sodium chloride solution is used, and certain parameters such as temperature and spray time are set. After a period of testing, observe whether the sample surface has corrosion, blistering, peeling, etc. The salt spray test can effectively evaluate the thermal fuse’s tolerance to the salt spray environment, thereby determining its applicability and weather resistance in relevant application scenarios.
(V) Ozone aging test
Ozone is a strong oxidant that can accelerate the aging process of materials. The ozone aging test exposes the thermal fuse sample to an environment containing a certain concentration of ozone, and observes the aging phenomena such as cracking and discoloration of the sample under specific temperature and humidity conditions. This method can quickly evaluate the ozone resistance of the thermal fuse and predict its anti-aging ability in actual use, thereby providing an important basis for the weather resistance evaluation of the product.

3. Relevant standards for weathering test of thermal fuses
Globally, many organizations and institutions have formulated standards and specifications for weathering test of thermal fuses. These standards provide enterprises and testing institutions with unified testing methods and evaluation basis. The following are some common standards:
(I) ISO standards
The International Organization for Standardization (ISO) has formulated a series of weathering test standards related to polymer materials such as plastics and rubber, which can also be applied to the testing of thermal fuses. For example, ISO 4892 “Plastics – Laboratory light source exposure test methods” specifies the methods and conditions for material aging tests using different types of light sources (such as xenon arc lamps, ultraviolet fluorescent lamps, etc.), and provides detailed guidance for ultraviolet irradiation tests of thermal fuses. ISO 14136 “Textiles – Color fastness tests – Color fastness to artificial light: xenon arc lamps” can be used to evaluate the color stability and related performance changes of thermal fuses under lighting conditions.
(II) ASTM standards
The standards of the American Society for Testing and Materials (ASTM) have a wide influence in the field of material testing. For example, ASTM D2565 “Standard Practice: Relative Weathering Test of Plastics Exposed with Xenon Arc Lamp Apparatus” and ASTM G154 “Standard Practice: Ultraviolet Exposure Test with Fluorescent Ultraviolet Lamp”, etc., these standards specify in detail the equipment requirements, test conditions, sample preparation and result evaluation in the weathering test of hot melt wires, providing a strong guarantee for ensuring the accuracy and repeatability of the test results.
(III) GB/T Standard
China’s national standards (GB/T) also have weathering test standards for hot melt adhesives and other similar materials. For example, GB/T 16422.3-2014 “Plastics Laboratory Light Source Exposure Test Methods Part 3: Fluorescent Ultraviolet Lamp” specifies the methods and requirements for weathering test of plastic materials using fluorescent ultraviolet lamps, which can provide a reference for ultraviolet weathering test of hot melt wires. In addition, standards such as GB/T 27934.4-2011 “Control and test methods for laminating paper printed materials Part 4: Reactive polyurethane (PUR) hot melt adhesive, i.e. coating film” also involve relevant performance tests of hot melt adhesive materials, including weather resistance.

4. Factors affecting weather resistance of hot melt wires
Understanding the factors affecting weather resistance of hot melt wires will help us take corresponding measures in the production, selection and use process to improve the weather resistance of products.
(I) Raw materials
The raw materials of hot melt wires are one of the important factors that determine their weather resistance. Different polymer materials have different chemical structures and performance characteristics, and their resistance to environmental factors such as ultraviolet rays, oxygen, and moisture is also different. For example, polyamide hot melt wires usually have good weather resistance and chemical resistance, while some lower-priced polymer materials may be slightly inferior in weather resistance. In addition, additives in raw materials, such as ultraviolet absorbers, antioxidants, stabilizers, etc., also play a key role in the weather resistance of hot melt wires. The right amount of additives can effectively improve the anti-aging ability of the thermal fuse and extend its service life.
(II) Production process
The production process of the thermal fuse also has an important impact on its weather resistance. For example, in the production process, improper control of process parameters such as temperature, pressure, and cooling speed may lead to problems such as uneven internal structure and molecular chain damage of the thermal fuse, thereby reducing its weather resistance. In addition, impurities and moisture in the production environment will also affect product quality. Therefore, strictly controlling production process parameters, optimizing production processes, and ensuring the cleanliness and stability of the production environment are one of the key links to improve the weather resistance of the thermal fuse.
(III) Use environment
The actual use environment of the thermal fuse determines the weather resistance challenges it faces. If the thermal fuse is in a harsh outdoor environment for a long time, such as high temperature, high humidity, strong ultraviolet radiation, and chemical pollution, its weather resistance will be consumed faster and its performance will deteriorate more significantly. Therefore, when selecting a thermal fuse product, it is necessary to fully consider its specific application environment, select the appropriate type of thermal fuse according to the environmental conditions, and take corresponding protective measures, such as adding a protective layer in outdoor applications or performing regular maintenance to improve the service life and reliability of the product.

5. How to choose hot melt wire according to weather resistance test results
As an international wholesale purchaser, when choosing hot melt wire products, you should pay full attention to the weather resistance test results, and make reasonable choices based on the application requirements and use environment of your own products.
Clear application requirements: First, you need to clarify the specific application field and use environment of the purchased hot melt wire, including temperature range, humidity conditions, whether it is exposed to the sun, whether it will come into contact with chemicals and other factors. For example, if it is used for the lamination of outdoor advertising materials, you need to choose hot melt wire with excellent UV resistance and moisture resistance; if it is used for bonding of automotive interiors, you need to consider the stability and chemical corrosion resistance of the hot melt wire in high temperature environment.
Pay attention to test data: Carefully study the hot melt wire weather resistance test report provided by the supplier, and focus on the results of various test indicators. Such as tensile strength retention rate and elongation at break retention rate after ultraviolet irradiation, appearance changes and bonding performance changes after temperature cycle test, water absorption and dimensional stability after moisture and heat test and other data. By comparing the test data of hot melt wires of different brands and models, select products whose performance indicators meet or exceed the standard requirements.
Consider the cost performance: Under the premise of meeting the application requirements, comprehensively consider the price and performance of the thermal fuse. Although the price of high-performance thermal fuses may be relatively high, they can provide more reliable performance and longer service life in the long-term use process, thereby reducing the overall cost of use. Therefore, it is necessary to weigh the relationship between price and performance according to your own budget and product quality requirements, and choose the most cost-effective thermal fuse products.

6. Conclusion
The weather resistance test of thermal fuses plays a vital role in ensuring product quality and stable performance. Through the introduction of this article, we have a deep understanding of the importance, methods, standards and related influencing factors of thermal fuse weather resistance testing. In the actual international trade procurement process, buyers should fully realize the value of weather resistance testing, strictly require suppliers to provide reliable product test reports, and choose suitable thermal fuse products according to their own needs. At the same time, we also hope that domestic thermal fuse manufacturers can continuously improve the weather resistance of their products, strengthen technology research and development and quality control, so as to meet the international market’s demand for high-quality thermal fuses and enhance the competitiveness of my country’s thermal fuse products in the international market.

In short, only thermal fuses that have undergone rigorous weather resistance testing and have excellent performance can maintain stable and reliable performance under various complex environmental conditions and provide strong support for the production and development of various industries around the world.