Liquid Type ( ELEC - QN , )   

         Antistatic agents

                      additives for Plastics processing

CONTENTS      1. Antistatic agents        1-1) Functions and mechanism of antistatic agents.        1-2) Types of antistatic agents        2-4) Evaluation methods for antistatic effect             2-4-1) Sensory method             2-4-2) Evaluation by electric properties

1. Antistatic agents

1-1) Functions and mechanism of antistatic agents.

       Electric nonconductivity is one of the various advantages that plastics possess generally. However, there are cases where this advantage turns to be a defect that static electric charge accumulates on the surface of plastics. Static electricity gives troubles such as electric shock, dust attraction and sticking of films.

      Antistatic agents are used to solve the problems as related above by giving atistatic properties to plastics without altering the general mechanical properties of the plastics.

      Antistatic agents have in their molecules both hydrophobic and hydrophilic radicals. Practically, the hydrophobic radicals turn to the surface of plastics, while the hydrophilic radicals turn to the air attracting the moisture in the atmosphere.

      The static charge accumulation in plastics is dissipated, through the conductivity of water absorbed by antistatic agents.

      At the same time, antistatic agents show the action of reducing the accumulation of frictional static charge. Thus, antistatic effect is obtained.

1-2) Types of antistatic agents                                                     ^TOP

      From usage standpoint, they are classified broadly into two types, namely external antistatic agent and internal antistatic agent.

      The external type is applied on the surface of plastic articles by spraying or dipping with dilute solution, and after drying it makes very thin conductive layer on the surface. The internal type is used by incorporating it into plastics before processing. The incorporated antistatic agents igrate to the surface after processing and make very thin electric conductive layer.

      Master batch type is a kind of internal type and used for convenience in handling and usage. This type is made by blending high loading of the antistatic agent into resin and formed to pellet shape.

Table 1. The effects of external antistatic agents

 

Molded plastics	Antistatic agents	Dilution (times)	Application method	Surface resistivity	Results of dirt cham- bertest	Remarks
Polypropylene, molded by infection	------- ELEC QN   ELEC AC   LOVING BS-2	50 100 50 100 50 100	Spray Spray Spray Spray Dipping Dipping	<1.0 x 109 5.8 x 109 1.1 x 1010 3.8 x 1010 9.4 x 1010 2.3 x 1011	x 0 0 0 0   ^	For food pack- ing or wrapping
ABS, molded by injection	------- ELEC QN   ELEC AC   LOVING BS-2	50 100 50 100 50 100	Spray Spray Spray Spray Dipping Dipping	<1.0 x 109 5.3 x 109 1.2 x 1010 2.2 x 1011 1.1 x 1011 1.5 x 1011	x 0 0 0 0 0 0	For food pack- ing or wrapping
Polystyrene, molded by injection	------ ELEC QN   ELECAC   LOVING BS-2	50 100 50 100 50 100	Dipping Dipping Dipping Dipping Dipping Dipping	<1.0 x 109 5.3 x 109 9.0 x 109 3.6 x 1010 7.5 x 1010 3.8 x 1010	x 0 0 0 0 0 x	For food pack- ing or wrapping
Rigid PVC sheet	------ ELEC QN   ELEC AC   LOVING BS-2	50 100 50 100 50 100	Spray Spray Spray Spray Spray Spray	>1.0 x 1017 <1.0 x 109 5.8 x 109 1.1 x 1010 3.8 x 1010 7.0 x 1010 1.0 x 1011	x 0 0 0 0 0 0	For food pack- ing or wrapping

Remarks : 0 good

               ^ moderate                 *Dirt chamber test is explained in the paragraph 2-4-1.

               x low

The durability of effects

The change on 6 months standing of the injected polypropylene specimens dipped in the solution of antistatic agent revealed that the specimen still had sufficient antistic effect as shown in the Table 8.

Table 2. The result of 6 months standing of the specimen of injected polypropylene

Parts, dipped in the solution of antistatic agent

Antistatic agent	Dilution (times)	Surface resistivity
		1 day after	7 days after	1 months after	6 months after
ELEC QN ELEC AC	200 100	1.2 X 1010 3.8 X 1010	2.2 X 1010 4.5 X 1010	8.3 X 1010 1.2 X 1010	1.4 X 1011 3.6 X 1012

2-4) Evaluation methods for antistatic effect

      It is necessary to evaluate if the antistats blended or applied are virtually effective.

     The methods commonly employed for the evaluation of antistatic agents are introduced hereafter

2-4-1) Sensory method

- Dirt chamber test                                                                    ^TOP

      This method is specified by ASTM D2741 designation to cover the determination of the relative susceptibility of plastics to soot accumulation.

      The specimen of plastics is put in a chamber to be exposed to the soot created by burning toluene-wetted paper and circulated in the chamber.

      After the definite time the specimen is taken out from the chamber, then soot accumulation on the surface of the specimen is rated visually.

2-4-2) Evaluation by electric properties

- Surface resistivity

      This method is specified by ASTM D257. Preparing proper electrodes on the surface of the specimen, the surface resistivity between the electrodes is measured by a high resistance meter.

- Decay of charged static electricity

      The surface of the specimen is charged by corona discharge, and then the decay of static electricity is measured by means of static potential meter.

      "Static honestmeter",made in Japan and sold commercially, enables to measure the decay on standing of the antistatic accumulation which is made visible by use of oscillograph. To make correct determination by this method, it is essential to conduct the evaluation under the constant temperature and humidity.

                                                                                                  ^TOP

CENO Anti 060U (Liquide type) : 20 Liter CAN

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