Starting from 1984, Volkswagen in Germany installed plastic fuel tanks on their large sedans assembled in the United States. In 1996, about 1/4 of cars produced in North America used plastic fuel tanks. In Japan, in 1977, the Japanese Ministry of Transport issued the initial plastic fuel container standard, allowing the use of plastic fuel tanks in domestic cars. Prior to this, in 1976, Toyota Motor Company used EHMW-HDPE gasoline tanks on cars exported to Europe.

In 1984, Nissan Motor Company began producing and selling Santana cars under a contract with VW, which used HDPE gasoline tanks. In addition, cars imported from West Germany and equipped with HDPE fuel tanks have also appeared in the Japanese market, all of which have passed the inspection standards of the Japanese Ministry of Transport. Today, the use of plastic fuel tanks is increasing, and their application prospects are becoming increasingly broad. Compared with metal fuel tanks, plastic fuel tanks have the following advantages:

Lightweight by 40%~50%; The shape has greater degrees of freedom, which can maximize the effective space under the car seat, increase the volume of the fuel tank, and improve the utilization of car space; The mold development cycle is short, about one-third of that of a metal oil tank; Safety and reliability are no less than metal fuel tanks.

When conducting a drop hammer impact test with a heavy hammer at -18 ℃ and an impact energy of 120N · m, the two showed comparable results. Plastic has low heat transfer properties, can soften upon ignition, allows fuel to flow out at atmospheric pressure, and will not explode like metal fuel tanks. In addition, it has good corrosion resistance.

This is also a disadvantage of HDPE fuel tanks, which have lower resistance to the effective components of fuel. The research focus on plastic fuel tanks in various countries around the world is mainly focused on solving this problem. With the continuous improvement of environmental and safety requirements in various countries, the requirements for fuel tank permeability resistance are becoming increasingly stringent. The regulations regarding fuel tank leakage in various regions have also been continuously improved. For example, in Europe, it is mainly based on Chapter 34.5 of the ECE rules. Based on this, the average fuel loss within 8 weeks at 40 ℃ in the fuel tank shall not exceed 20g/d. However, the anti permeability performance of ordinary HDPE fuel tanks is limited. In order to meet higher anti permeability requirements, modified HDPE fuel tanks, multi-layer fuel tanks, and surface treated fuel tanks have emerged. In addition, to meet and improve the requirements of temperature resistance, fire resistance, and impact resistance of plastic fuel tanks, corresponding methods and measures have also emerged for fuel tanks. Here is an introduction. The raw materials for producing single-layer plastic fuel tanks mainly include high-density polyethylene and a mixture of polyethylene. High density polyethylene refers to EHMW-HDPE, with a molecular weight generally above 200000 and a melt flow rate

It is 4-12g/10min (21.6kgf/cm2 ≈ 2.16MPa), with a density of about 0.945g/cm3. Famous brands include BASF's 4261A and Hoechst's GM7746 from Germany; HXM50100 from Phillips, USA; Showa Denko's 4551Z and Tohoku's B5742. In addition, there is also the AX4013 from Huls, Germany. Polyethylene mixtures can be divided into layered mixtures [4-8] and non layered mixtures. In the early 1980s, DuPont Company in the United States successfully researched the SelarRB layered mixing technology. Dry mixing of barrier polymers (such as modified PA or amorphous PA) with polyolefins (such as HDPE) and a small amount of compatibilizer, using a moderately mixed extruder to extrude and expand, forming a layered structure inside the container wall, resulting in many discontinuous barrier thin sheets (usually 0.5-50 thick) μ m) Distributed in HDPE base material.