Preparation method for permanently antistatic and conductive EVA

Abstract

The invention provides a preparation method for permanently antistatic and conductive EVA. The preparation method comprises the following concrete steps: (1) adding LDPE, EVA and calcium powder into an internal mixer, then carrying out stirring, carrying out heating to 95 to 105 DEG C, and opening a water temperature control system of the internal mixer; (2) maintaining a temperature in a range of95 to 105 DEG C, adding conductive carbon black, aromatic oil, a cross-linking agent and zinc oxide into the internal mixer, continuing stirring, and heating the internal mixer to 110 to 120 DEG C; (3) maintaining the temperature in a range of 110 to 120 DEG C, adding a foaming agent into the internal mixer, closing the water temperature control system of the internal mixer, continuing stirring,and carrying out heating to 125 DEG C; and (4) discharging a material, placing the material into an open mill with a size of 18'', allowing the material to pass through rollers two times, allowing anobtained material to enter an open mill with a size of 16'' so as to obtain sheets, and carrying out foaming through a pressing machine so as to obtain a finished product. The product prepared by using the preparation method provided by the invention is permanently antistatic and permanently conductive, and has the advantages of good surface controllability, smooth surface and no pores at the sametime.

Description

technical field [0001] The invention relates to the technical field of antistatic and conductive materials, in particular to a preparation method of permanent antistatic and conductive EVA. Background technique [0002] EVA refers to ethylene-vinyl acetate copolymer, which is a new type of environmentally friendly plastic foam material. It has the advantages of good cushioning, shock resistance, heat insulation, moisture resistance, and chemical corrosion resistance, and is non-toxic and non-absorbent. In some special occasions, such as gas stations, chemical plants, etc., the anti-static requirements are very high, so anti-static materials are required. At the same time, some sophisticated electronic parts also require strict control of static electricity, so anti-static materials are also required. Therefore, how to produce antistatic and conductive EVA materials has become a research hotspot. [0003] The existing process is mainly to put the large material into the int...

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Problems solved by technology

[0004] This process has strict requirements on raw materials such as conductive carbon black, but the electrical properties of the obtained product are prone to instability, and the product is prone to uneven surface and internal holes.

The root causes of these shortcomings are as follows: (1) In the early stage of banburying, the temperature of the banbury mixer is not high and the raw material is cold material, so the conductive carbon black is stirred vigorously in the banbury mixer for a long time, resulting in the electrical properties of the conductive carbon black Big loss

(2) In the initial stage of banburying, the large material is not melted, and the conductive carbon black cannot be attached to polyethylene or EVA and flies everywhere, causing losses, resulting in uncontrollable electrical properties

(3) If there is a lot of conductive carbon black flying on the pressurized cover and the side of the hopper, when adding the foaming agent, it is usually swept into the hopper, which affects the dispersion of the material, so that the electrical performance of the product is poor and holes appear

(4) Because the internal mixer system does not carry out strict temperature control, the temperature of the melt will rise too fast, so that the stirring time between the conductive carbon black and the melt will be reduced, and the conductive carbon black will be unevenly distributed, thereby affecting the electrical properties of the product and holes appear

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