Wuhan HanDern Selection and use of filler
DATE：2020/12/3 10:20:05 / READ： / SOURCE：This station
Wuhan HanDern Selection and use of filler
1. The choice of filler
Mainly depends on the particle size and distribution, particle shape, surface area, stacking method (or stacking density) and chemical composition, but also consider its physical properties, such as thermal properties, optical properties and electrical properties.
(1) Particle size The shape, size and distribution of particles are important factors governing the size of the contact interface interaction. For example, these three factors will affect the gloss, air entrainment, permeability, flame retardancy, mechanical properties (tensile strength, elongation and hardness, creep) and dimensional stability of PVC, as well as rheological properties. , Abrasion resistance, etc.
The fillers used for reinforcement are expected to be flakes, fibrous and needle-shaped special-shaped fillers. Spherical and flake-shaped can help improve the modulus;
Or long fibers can improve impact performance. handern.com Extrusion Lamination Compound Equipment
(2) Surface area Many functions of the filler are related to its surface area. Surfactants, dispersants, surface modifiers and polar polymers can all be adsorbed or chemically reacted on the surface of the filler.
(3) Particle packing density When the filler is only used to improve the particle size of the composite material, the packing density is required to be small, that is, the packing is loose, and the use of fibers or long needle particles is the most effective; if the resin price is high, the packing density is required to be large to reduce The amount of resin. The packing density is related to the particle shape, size and stacking method. handern.com Extrusion Lamination Compound equipment
(4) Chemical composition The chemical composition determines some basic properties of the filler. Special attention should be paid to the chemical activity of the filler surface, the type and quantity of impurities, the pH value, the amount of acid-soluble substances, water solubility and ignition loss.
(5) Optical properties The color and particle size of the filler should be considered for light reflection (refraction, bending), refractive index, ultraviolet absorption, fluorescence, and thermoluminescence. handern.com Extrusion Lamination Compound Equipment
(6) Thermal performance Thermal conductivity, specific heat capacity, thermophysical effects, thermochemical effects, thermal expansion coefficient, etc.
(7) Physical properties From the perspective of economic effects, density is an important parameter, hardness is also an important factor, and the friction coefficient depends on the particle shape, surface characteristics, crystal and inter-particle bonding force. Porosity is closely related to absorption; in addition, electrical properties are also important factors that should be considered.
2. The function and problems of reinforcing filler
Most fillers have a certain reinforcing effect. As a reinforcing filler, it should have the following functions:
(1) Increase the notched impact strength, flexibility resistance, tensile strength and surface hardness;
(2) Improve dimensional stability, heat resistance (including thermal shrinkage and thermal expansion), creep resistance, wear resistance and flame resistance.
The existing problems are: ①The elongation and processing performance are reduced, and the impact strength is generally reduced; ②The abrasion of processing machinery and molds increases; ③The surface is rough; ①Some costs will increase. handern.com Extrusion Lamination Compound equipment
3. Types and functions of functional fillers
The special functions that functional fillers may give are: electrical conductivity, heat conduction, flame retardancy, lubrication, vibration, sound insulation, piezoelectricity, magnetism, insulation, heat insulation, radiation resistance, light scattering and light reflection.
Author：admin