JPS6223707Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a protective cover for a resin fuel tank. Resin fuel tanks have the characteristics of being lighter and having better corrosion resistance than general metal tanks. However, because they are made of resin, they are inferior to metal tanks in terms of heat resistance.

The object of the present invention is to provide a heat insulating cover that effectively protects a resin fuel tank from abnormally high temperature outside air above a certain temperature. A further object of the present invention is to provide a heat insulating cover that is lightweight and inexpensive, as well as insulating heat in emergency situations.

The heat insulating cover of the present invention uses a sheet-shaped resin glass fiber composite material made by compressing glass mat in the thickness direction and fixing it with a thermoplastic resin containing a foaming agent. It has a shape that covers. When the insulating cover of this invention is exposed to outside air at an abnormally high temperature above a certain temperature, the resin that is a component of the sheet-shaped resin-glass fiber composite material melts, and the foam expands in the thickness direction. The compressed glass pine bulges in the thickness direction, creating a thick layer of glass pine that blocks abnormal heat above a certain temperature and protects the resin fuel tank on the other side from abnormally high temperatures in an emergency situation. It protects from

Since a large number of glass fibers are oriented in the thickness direction as well as in the spreading direction of the mat, the glass mat itself swells in the thickness direction, resulting in an even higher heat insulating effect.

Such a glass mat may be a glass mat made of glass fibers wound in a loop shape, or a glass mat made of glass fibers formed by performing numerous needle punches in the thickness direction of a glass mat oriented in the direction in which the mat spreads in a normal two-dimensional direction. This is a glass mat that is mechanically oriented in the thickness direction of the mat.

As the thermoplastic resin, ordinary resins such as polyethylene, polypropylene, ABS resin, and nylon, which are hard at room temperature and soften when heated, can be used. This thermoplastic resin acts as a binder to fix the glass mat at room temperature, softens upon heating, and forms a foam together with the glass fibers due to the foaming agent contained therein. In addition to the blowing agent described later, an inorganic filler and a flame retardant may be added to the thermoplastic resin. However, it is not preferable that the formation of a foam is inhibited by the addition of fillers and the like.

The blowing agent is one that decomposes with heat and generates gases such as nitrogen gas and carbon dioxide gas, and ordinary blowing agents used for thermoplastic resins can be used. Note that the foaming temperature of the foaming agent needs to be higher than the molding temperature (softening melting temperature) of the thermoplastic resin in which it is blended.

The method of pressing the glass mat in the thickness direction and fixing it with resin is to interpose a thermoplastic resin containing a foaming agent between the glass fibers and heat it above its melting point to below the foaming temperature of the foaming agent. A method can be adopted in which the resin is pressed in the glass fibers by pressing in the direction, the resins are melted and connected to each other, and the resin is cooled and solidified in that state, and the glass fibers are fixed by solidification of the resin.

In addition, as a method of using thermoplastic resin sheets, thermoplastic resin sheets containing a blowing agent are layered on the top and bottom surfaces of a glass mat, heated to a temperature above the melting temperature of the thermoplastic resin and below the foaming temperature of the blowing agent, and compressed in the thickness direction. The molten thermoplastic resin sheet is then pressed into the glass fibers and cooled in that state.
Glass fibers can also be fixed. In addition, when making a thick resin-glass fiber composite material, resin sheets, glass mats, resin sheets, glass mats, resin sheets, etc. can be laminated alternately.

The appropriate thickness of a heat insulating cover used for a resin fuel tank of an automobile or the like is approximately 2 to 10 mm in a compressed state.

A method for forming a heat insulating cover into a shape that covers the bottom and side surfaces of a resin fuel tank is to heat the sheet-shaped resin glass fiber composite material, press-form it in a plastic state, and then cool the composite material in that state. The shape and the glass fibers are fixed in a compressed state in the thickness direction.

When the heat insulating cover of the present invention is exposed to outside air at an abnormally high temperature above a certain temperature, the resin in the wall forming the heat insulating cover softens, and the foaming agent foams and expands in the thickness direction. The foam, which includes expanded glass mats, increases the heat insulation effect. For this reason,
The resin fuel tank can be effectively protected from high temperature outside air in abnormal situations.

Incidentally, since the glass fibers of the glass mat are oriented in the thickness direction of the glass mat, the elasticity of the glass fibers is restored by softening of the thermoplastic resin, and the glass mat expands in the thickness direction. Therefore, the expansion of the sheet in the thickness direction along with the action of the foaming agent becomes more reliable. In addition, since the glass fibers of the glass mat are oriented in the thickness direction, even if the resin that binds the glass fibers melts and disappears, the glass fiber mat alone retains its shape and maintains its insulation effect. I can do it.

This will be explained below using examples.

Using an ordinary glass mat made by stacking glass fibers with a length of 50 mm or more, a large number of punches are performed in the thickness direction of this glass mat, and a large number of glass fibers are oriented in the thickness direction with a bulk specific gravity of 0.15 at a thickness of 10 mm. A glass mat with sufficient shape retention properties was produced. A high-temperature foaming agent such as barium azodicarboxylate or trihydrazinotriazine is applied to both sides of the glass mat for 3 to 20 minutes.
Polypropylene sheets with a thickness of 1.5 mm containing % by weight are stacked and heated to 220°C, and pressed in the thickness direction to compress the glass mat in the thickness direction and press the molten polypropylene into the gaps between the glass fibers. While the composite material retained its flexibility, or after the resin was heated again to melt it, it was compression molded in a cooling mold consisting of an upper mold and a lower mold. The heated and flexible resin glass fiber sheet is cooled in a mold to solidify the resin, and the glass mat is fixed in a compressed state in the thickness direction. The insulation cover shown in the figure was formed.

This heat insulating cover 1 is attached to the fuel tank 3 as a protective cover for the lower and side surfaces of the fuel tank 3 provided under the rear trunk compartment 2 of the automobile shown in FIG. It is fixed below the rear trunk compartment 2. In order to examine the heat insulating properties of this heat insulating cover, one side of the heat insulating cover was exposed to high temperature outside air caused by a fire. The resin melted in the areas exposed to high-temperature outside air due to this fire, and the sheets and glass mats swelled in the thickness direction, improving the heat insulation effect compared to those that did not implement the present invention.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a state in which a heat insulating cover, which is an embodiment of the present invention, is attached to a fuel tank, and Fig. 2 is a schematic partial cross-sectional view of a car with the heat insulating cover and fuel tank of Fig. 1 attached. be. In the figure, reference numeral 1 indicates a heat insulating cover, 2 indicates a trunk room, 3 indicates a fuel tank, and 4 indicates a band.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The bottom and side surfaces of a fuel tank are made by press-molding a sheet-like resin-glass fiber composite made by compressing glass mat in the thickness direction and fixing it with thermoplastic resin containing a foaming agent. A heat insulating cover for a resin fuel tank, characterized in that it has a shape that covers the resin tank and has a structure that protects the resin tank from abnormally high temperatures. (2) The heat insulating cover for a resin fuel tank according to claim 1, wherein the glass mat has many fibers oriented in its thickness direction. (3) The heat insulating cover for a resin fuel tank according to claim 2, wherein the glass mat is needle-punched in the thickness direction so that the fibers are oriented in the thickness direction.