Selection of plastic materials
Variety of plastics:
In product design, the selection and application of materials often play a key role. Selecting the correct material can make the product meet the expected function, appearance, strength and ensure that the due quality and durability are maintained within the set period. Among the various materials, the plastic material has become the material of choice for most products due to its excellent molding and processing characteristics, light weight, high production efficiency, product diversification, and high complexity of products.
Types of plastic:
Plastic is a high molecular compound, its molecular chain is more than 10,000, and it has basic strength characteristics. The chemical reaction of plastic in its thermal properties is generally divided into thermoplastic plastic and thermosetting plastic. Among many products, if there is basic strength Requirements, environmental durability requirements, special environmental applications, etc. Most of these products use engineering plastics (PA, PC, PBT, PPO, PET, POM...), and basically in our daily life, most of the common plastic materials are Universal plastics (PP, PE, PS, ABS, PMMA). In special manufacturing processes, aerospace industry, military applications, etc., there are extremely high requirements. The basic temperature resistance and low creep characteristics are far greater than engineering plastics. This type of plastic belongs to high-performance engineering plastics (PPS, PAR, LCP) , PSF, PEEK, PI...) Due to the high price of this plastic material and the difficulty in processing and molding, most products are rarely used except for the specified use of the above-mentioned special environment or product requirements of the process.
Description and application of plastic materials (1)
Description and application of plastic materials (2)
Description and application of plastic materials (3)
When selecting plastic materials, first, according to the product use requirements, refer to the material property table to select suitable materials. The product use requirements can be roughly divided into mechanical physical property requirements, chemical requirements, use environment requirements, functional requirements, secondary processing requirements, and cost. Requirements, certification needs...etc. The physical properties of general plastic materials include mechanical properties, impact properties, temperature resistance properties, physical properties, electrical properties, fire rating, and recommended molding conditions. Through the comparison table of physical properties of plastic materials, you can understand the pros and cons of materials, determine the priority of materials, and choose the right one. materials to use.
Then, it should be based on the use situation of the product and the possible impact of the material. For example, the addition of various types of fire retardants to fire-resistant and fire-resistant materials will usually make the impact resistance of the material itself worse. If there is a need for warping resistance, various types of additives such as glass fiber, mineral fiber, talcum powder, etc. are usually added to the material. Although the use of crystalline materials can greatly improve the temperature resistance of the environment, it is easy to Floating fibers and white fog appear on the surface of the product, which will affect the appearance. The strengthening of certain characteristics of plastic materials is often accompanied by the trade-off of other relative characteristics. If only one aspect is considered when selecting materials, it is easy to cause problems in the subsequent reliability or certification of products. Problems caused by improper material selection may result in considerable losses. The shrinkage rate, tensile deformation, demolding angle, and molding conditions of different materials are different. If the material needs to be replaced in the later stage of development, it is usually necessary to repair the mold, reopen the mold, or even change the design to match the change, resulting in the overall development cost. A substantial increase.
From the survey report, we can see that in the past few years, the demand for plastic materials for products is mainly flame-retardant materials, followed by impact resistance and warpage resistance. Especially in recent years, the application of plastic materials has become more and more diversified. Due to the rising awareness of environmental protection and the impact of the epidemic, the demand for antibacterial materials, post-consumer recycled materials (PCR) and biodegradable materials has increased, and the use of biocompatible materials has also increased. increasing day by day.
