How does hot melt material affect compression performance?

How does hot melt material affect compression performance?
In many fields of industrial production, hot melt wire has attracted much attention due to its unique properties and wide application. For independent stations of hot melt wire, it is very important to understand how hot melt wire materials affect compression performance, which is not only related to the quality and performance of the product, but also directly affects the customer’s purchasing decision. This article will explore the relationship between hot melt wire materials and compression performance in depth, aiming to provide valuable information for international wholesale buyers.

Types of hot melt wire materials
Polyolefins: Polyethylene (PE) and polypropylene (PP) are common polyolefin hot melt wire materials. They have good flexibility and certain strength, low cost, and are widely used in packaging, textiles and other fields. Its melting point is relatively low, it is easy to melt when heated, and can achieve bonding and compression molding at a lower temperature.
Polyester: Polyethylene terephthalate (PET) is a typical polyester hot melt wire material. It has high strength and good heat resistance and chemical corrosion resistance, and is suitable for automotive interiors, industrial filtration and other fields. PET hot melt wire has a high melting point, generally around 250-260℃, and can maintain good performance at higher temperatures.
Polyamide: Nylon (PA) is the representative of polyamide hot melt wire. It has excellent strength, toughness and wear resistance, and is often used in clothing, footwear and other industries. The melting point of PA hot melt wire is generally between 180-220℃, and its hygroscopicity is relatively large, which may affect its compression performance under certain specific environments.
Polyurethane: Polyurethane (TPU) hot melt wire has good elasticity and flexibility, as well as excellent low temperature resistance. It is widely used in sports equipment, medical equipment and other fields. The melting point of TPU hot melt wire can be controlled in a wide range by adjusting the raw material properties, usually between 80-160℃.

Effect of hot melt material composition on compression performance
Crystallinity: Hot melt materials with higher crystallinity have more orderly molecular chain arrangement and stronger intermolecular forces, which enables the material to better resist deformation when compressed, thereby improving compression strength. For example, polyethylene materials with high crystallinity often have better compression properties than polyethylene materials with low crystallinity.
Molecular weight and its distribution: Hot melt materials with high molecular weight usually have better mechanical properties, including compression properties. A larger molecular weight means a longer molecular chain, more interchain entanglements, and the ability to withstand greater pressure. At the same time, materials with a narrower molecular weight distribution have more uniform and stable properties, and are less likely to have local weaknesses that cause deformation or rupture during compression.
Additives: In order to improve the performance of hot melts, some additives such as plasticizers, stabilizers, fillers, etc. are often added. The addition of plasticizers can improve the flexibility of the material, but may reduce the compression strength of the material to a certain extent; stabilizers can improve the thermal stability and aging resistance of the material, thereby indirectly extending the service life of the material under compression; the addition of fillers can improve the rigidity of the material and increase the compression modulus, but may also affect other properties of the material, such as reducing toughness.

Effect of hot melt structure on compression performance
Skin-core structure: Semi-melting hot melts are usually skin-core composite structures, with the core being ordinary material and the skin being low-melting-point material. When compressed, the skin material melts first, and the core material provides support to a certain extent. The strength and rigidity of the core material have an important influence on the compression performance of the overall thermal fuse. If the core material has a high strength, it can maintain a certain shape and size after the skin melts, so that the thermal fuse has better stability and compressive resistance during compression.
Fiber structure: The fiber structure of the thermal fuse, such as the diameter, length, orientation, etc. of the fiber, will also affect its compression performance. Thinner fibers are more easily deformed during compression, but they have a larger specific surface area and a larger contact area with other materials, which can better disperse stress in composite materials; longer fibers can provide better mechanical support during compression and improve the compression strength of the material; fibers with a higher degree of orientation have molecular chains arranged along the fiber axis, and have better compression performance along the fiber axis, while the compression performance in the vertical direction is relatively poor.

Compression performance test and evaluation of thermal fuse materials
Test method: Common compression performance test methods for thermal fuse materials include static compression test and dynamic compression test. The static compression test is to place the hot melt sample between the pressure plates of the compression tester, apply pressure at a certain speed until the sample reaches a certain deformation or is damaged, and measure its compression stress-strain curve to obtain parameters such as compression strength and compression modulus. The dynamic compression test is to apply high-speed impact loads to the sample through equipment such as impact testers to study its compression performance and deformation behavior under dynamic conditions.
Evaluation indicators: Compression strength is a measure of the maximum stress that the hot melt material can withstand during compression, which reflects the material’s compressive resistance; compression modulus indicates the stiffness of the material during compression, that is, the material’s ability to resist deformation when under pressure; in addition, it also includes indicators such as resilience and permanent deformation after compression. These indicators jointly determine the compression performance of hot melt materials in practical applications.

Requirements for compression performance of hot melt materials in different application scenarios
Packaging field: In the packaging industry, hot melt wires are often used to make packaging tapes, packaging nets and other products. These products need to have a certain compression strength to withstand the pressure during packaging and the load generated during stacking. At the same time, they also need to have good resilience, so that they can recover in time when the shape of the package changes and maintain the tightness of the package. Therefore, for hot melt materials for packaging, they are usually required to have moderate compression strength and high compression modulus, as well as good elastic recovery performance.
Automotive industry: Automotive interior parts such as seats and dashboards need to be bonded and fixed with hot melts. These parts are subject to various vibrations and impact loads during the driving process of the car, so hot melt materials are required to have high compression strength and good fatigue resistance to ensure the stability and reliability of interior parts during long-term use. At the same time, in order to meet the needs of lightweight automobiles, hot melt materials also need to reduce weight as much as possible while ensuring compression performance.
Electronic and electrical field: In electronic and electrical products, hot melts are used to fix circuit boards, connect electronic components, etc. As the size of electronic and electrical products is getting smaller and smaller, and the precision requirements are getting higher and higher, higher requirements are placed on the compression performance of hot melt materials. Thermofusible wires need to provide sufficient compression force in a tiny space to ensure good contact and fixation of electronic components. At the same time, they must have good heat resistance and insulation properties to adapt to the working environment of electronic and electrical products.

How to optimize the compression performance of thermofusible wire materials
Material modification: By modifying the thermofusible wire materials, their compression performance can be effectively improved. For example, by using copolymerization, blending and other methods, different types of polymers are combined to combine the advantages of each component to prepare thermofusible wire materials with good compression performance. The strength and modulus of the material can also be improved by adding reinforcing phases such as nanomaterials and fibers, thereby enhancing its compression performance.
Process optimization: The process parameters in the production process of thermofusible wires also have an important influence on the compression performance of the material. For example, controlling parameters such as spinning temperature and draft ratio can adjust the crystallinity and orientation of the fiber, thereby optimizing its compression performance. In addition, heat treatment processes such as annealing can also improve the molecular structure and performance of the material, and improve the compression strength and toughness of the thermofusible wire.

In short, the compression performance of thermofusible wire materials is one of its important mechanical performance indicators, which is affected by many factors such as material composition, structure, and production process. Understanding these influencing factors will help us better select and optimize thermal fuse materials to meet the performance requirements in different application scenarios.