Plastic formula design looks simple on the surface, but often simple things are not appreciated, thus affecting the final result. So, how do you design a high performance, easy to process, low price formula?
01Think clearly about the performance you want, and then choose the appropriate additives
(1) toughening
Selection of elastomer, thermoplastic elastomer and rigid toughening materials;
(2) enhancement
Choose glass fiber, carbon fiber, whisker and organic fiber;
(3) Flame retardant
Bromine (common bromine system and environmental bromine system), phosphorus, nitrogen, nitrogen/phosphorus complex expansive flame retardant, antimony trioxide, hydrated metal hydroxide;
(4) antistatic
All kinds of antistatic agents;
(5) Conducting electricity
Carbon (carbon black, graphite, carbon fiber, carbon nanotubes), metal fiber and metal powder, metal oxide;
(6) Magnetism
Ferrite magnetic powder and rare earth magnetic powder include samarium cobalt (SmCo5 or Sm2Co17), Neodymium iron boron (NdFeB), samarium iron nitrogen (SmFeN), aluminum nickel;
(7) Heat conduction
Metal fibers and metal powders, metal oxides, nitrides and carbides; Carbon materials such as carbon black, carbon fiber, graphite and carbon nanotubes; Semiconductor materials such as silicon and boron;
(8) Heat resistance
Glass fiber, inorganic fillers, heat-resistant agents such as substituted maleimides and β crystal nucleating agents;
(9) Transparency
Nucleating agent, for PP α crystal nucleating agent sorbitol series has the best effect;
(10) wear resistance
Graphite, molybdenum disulfide, copper powder and other cobalt magnetic powder three categories;
(11) Insulation
Calcined kaolin;
(12) barrier
Mica, montmorillonite, quartz, etc.
02Not only is the resin pick additives, additives for resin is also "picky"!
The form of auxiliaries with the same composition has a great influence on the modification.
(1) Red phosphorus flame retardant is effective on PA, PBT and PET;
(2) Nitrogen flame retardants are effective on oxygen-containing classes, such as PA, PBT, PET, etc.;
(3) the nucleating agent has a good effect on copolymer polypropylene;
(4) The heat-resistant modification of glass fiber has good effect on crystalline plastics, but poor effect on amorphous plastics;
(5) carbon black filled with conductive plastic, good effect in crystalline resin.
03The form of additives is different, the effect may be very different!
(1) The enhancement effect of fibrous additives is good:
The degree of fibrosis of additives can be expressed by length-diameter ratio. The greater L/D, the better the enhancement effect, which is why we add glass fiber from the vent.
(2) The melting state is better than the powder to maintain the length-diameter ratio and reduce the probability of fiber breaking;
(3) Good toughening effect and high brightness of spherical additives:
Barium sulfate is a typical spherical additive, so the filling of high gloss PP is barium sulfate with small amplitude rigid toughening.
04The granularity of additives is also very exquisite!
(1) Influence of particle size of auxiliary agent on mechanical properties:
The smaller the particle size is, the more beneficial it is to the tensile strength and impact strength of the filling material.
(2) Influence of particle size of auxiliary agent on flame retardant performance:
The smaller the particle size of the flame retardant, the better the flame retardant effect. For example, the smaller the particle size of hydrated metal oxide and antimony trioxide, the less the amount of addition to achieve the same flame retardant effect;
(3) Influence of auxiliary particle size on color matching:
The smaller the particle size of the colorant, the higher the coloring power, the stronger the covering power, the more uniform color;
(4) Influence of auxiliary particle size on conductivity:
Taking carbon black as an example, the smaller its particle size is, the more likely it is to form a network conductive pathway to achieve the same conductive effect, and the amount of carbon black added is reduced. But like colorants, there is a limit to particle size, particle size is too small to gather and difficult to disperse, but the effect is not good.
