The Forms of Additives

The Forms of Additives

Even though the additives are using the same ingredients ,ingredients with different form can play quite a great different impact on the role of modification for Plastic Film Production.

1. The Shape of Additives

The reinforcing effect of the fiber assistant is quite good. The degree of fibrosis of the additive can be expressed by the ratio of length to diameter, the greater the L/D, the better the effect, and that`s why we add glass fibers from the exhaust hole. It is better to keep the ratio of the length to diameter than when it is in powder status, and can reduce the probability of breaking.

Spherical auxiliaries could be used for good toughening effect and high brightness. Barium sulfate is a typical spherical additives, so the filling of high gloss PP is using barium sulfate.Barium sulfate cold also be used fro small rigid toughening.

2. The Size of Additives

A.Effect of Additives Size on Mechanical Properties

The smaller particle size, the more beneficial to the tensile strength and impact strength of the filling material.

B. Effect of Additives Size on Flame Retardant Properties

The smaller the size of the flame retardant, the better the effect of flame retardant. For example, the smaller the size of the hydrated metal oxide and the three antimony oxide, the less the amount of the same flame retardant effect was required.

C.Effect of Additives Size on Color Matching

The smaller the colorant particle size, the higher tinting strength and stronger hiding power and also the more uniform the color is. But the size of colorant is not the smaller the better, there is a limit value, and the limit values vary from different properties. For color, the limit size of azo colorant is 0.1μm , the limit size of phthalocyanine colorant is 0.05μm. Fro hiding power, colorant limit size is about 0.05μm.

D.Effect of Additives Size on Conductivity

Take carbon black as an example, the smaller the particle size, the easier to form a mesh conductive path, and thus to achieve the same conductive effect to reduce the required amount of carbon black. But as the same as colorant ,there is also limit size.If the size is too small and then it is easy to gather and difficult to disperse, thus the effect is decreased instead.

3. The Surface Treatment of Additives

The compatibility of resin and additives should be good enough so as to ensure that the additives and resin could be dispersed into expected structure, to achieve the design targets, to ensure the lasting effect in the service period, and remain the anti extraction, migration resistance and resistance to precipitation. For most of the formula, it is required that the auxiliary agent and the resin are evenly dispersed, but for the barrier property,it is required that the additives should be distributed as layers in the resin.

The good compatibility with the resin is the key to the efficiency and the increase of the amount of the resin. Therefore, it is necessary to improve its compatibility, such as the use of a compatible agent or coupling agent for surface activation treatment, etc..

The surface of all inorganic additives will be improved after treatment. In particular, the most obvious one is filling additives, and also glass fiber, inorganic flame retardant, and etc..

The surface treatment is mainly based on the coupling agent and the compatibility agent, and the coupling agent is a kind of maleic anhydride grafted polymer, such as silane, titanate and aluminate ester.