Plastic Pycnometer Manufacturer Analysis: Due to plastic's poor thermal conductivity, the inner layers of plastic parts cool slowly, forming a high-density solid layer with significant shrinkage. Therefore, parts with thick walls, slow cooling rates, and thick high-density layers exhibit greater shrinkage. Additionally, the presence or absence of inserts, along with their layout and quantity, directly affects material flow direction, density distribution, and shrinkage resistance. Consequently, the characteristics of plastic parts significantly influence the magnitude and directionality of shrinkage. Non-flow temperature: The maximum temperature at which no flow occurs under specified pressure.
1. Synthetic resin constitutes the primary component of plastics, typically accounting for 40% to 100% of the material. Due to its high content and the fact that resin properties often determine plastic properties, resin is frequently regarded as synonymous with plastic.
2. Fillers, also known as extenders, enhance plastic strength and heat resistance while reducing costs. They are categorized into organic and inorganic fillers. Organic fillers include wood flour, fabric scraps, paper, and various textile fibers. Inorganic fillers encompass glass fiber, diatomaceous earth, asbestos, carbon black, and others.
3. Plasticizers increase plastic's malleability and flexibility, reduce brittleness, and facilitate processing and molding. Typically, plasticizers are high-boiling-point organic compounds that are miscible with resins, non-toxic, odorless, and stable to light and heat. The most commonly used are phthalate esters.
4. Stabilizers are added to prevent degradation and damage of synthetic resins from light and heat during processing and use, thereby extending service life. Common stabilizers include stearates and epoxy resins.
5. Colorants impart vibrant, attractive hues to plastics. Organic dyes and inorganic pigments are commonly used as colorants.
6. Lubricants prevent plastics from adhering to metal molds during forming while ensuring smooth, attractive surfaces. Common lubricants include stearic acid and its calcium/magnesium salts.
7. Antioxidants prevent thermal oxidation during heating, molding, or high-temperature use, which can cause yellowing or cracking. Beyond these additives, plastics measured by a plastic hydrometer may also incorporate flame retardants, foaming agents, antistatic agents, and others to meet diverse application requirements.
