JP2001180305A - Fuel tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel tank that can exhibit a fire protection performance in a fire by virtue of a high flame resistance and of a fireproof insulating layer into which the residue after heating expands. SOLUTION: A fuel tank body is formed from a synthetic resin, and at least the lower-half external surface of the fuel tank body is provided with a layer that expands for heat insulation when heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a synthetic resin fuel tank used for automobiles and the like.

[0002]

2. Description of the Related Art Generally, a fuel tank made of a steel plate is used for an automobile or the like, and a fuel tank made of a synthetic resin has been proposed for the purpose of reducing the weight of the automobile. However, the fuel tank made of synthetic resin has almost no fire prevention effect in the event of a fire, which is a practical problem.

In order to solve such a problem, Japanese Patent Application Laid-Open No. Sho 59-48232 proposes a fuel tank made of a synthetic resin in which a foaming paint is applied to the outside. This foaming paint is composed of a system that foams by the reaction of a phosphorus compound, a polyhydric alcohol, and a nonflammable gas generating agent in the event of a fire.The foaming paint forms an insulating layer on the outer surface of the fuel tank, thereby melting the fuel tank. To prevent.

[0004] In general, a fuel tank of an automobile is often provided under the floor at the rear of the vehicle due to the layout of the vehicle body.
In addition to the fuel tank, heat generating sources such as an exhaust pipe and an exhaust gas purifying device are arranged below the floor. However, when the foaming paint is exposed to a certain high temperature for a long period of time, the reaction rate is reduced, so that the foaming ratio at the time of fire becomes low, and there is a problem that a predetermined heat insulating performance cannot be obtained.

[0005]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a fire-retardant property in the event of a fire by having high flame retardancy and expanding the residue after heating to form a fire-resistant heat-insulating layer. It is to provide a fuel tank that can be developed.

[0006]

The fuel tank according to the present invention comprises:
A fuel tank body made of a synthetic resin, and a layer that expands and insulates by heating is provided on at least the outer surface of the lower half of the fuel tank body.

Hereinafter, the present invention will be described in detail. The fuel tank body in the present invention is not particularly limited as long as it is formed of a synthetic resin. The fuel tank body may have a single-layer structure or a multi-layer structure made of different types of synthetic resins. The shape of the fuel tank also depends on the manufacturer, but there is no particular limitation.

As a general method of manufacturing the fuel tank body, for example, first, a synthetic resin (eg, polyethylene) in a molten state is once accumulated in an accumulator in an extruder, and then injected into a tube shape called a parison. Next, there is a blow molding method in which the parison is sandwiched in a mold having the shape of a fuel tank, and after that, air is blown to inflate the parison and pressed against the mold.

The thickness of the fuel tank body is not particularly limited, but is generally 3 to 8 mm.

The layer which expands and insulates by heating is preferably a sheet-like material. Examples of such a sheet-like material include "Fire Barrier" manufactured by 3M Company (sheet material comprising a resin composition containing chloroprene rubber and vermiculite). , Volume expansion coefficient: 3 times, thermal conductivity: 0.20 kcal
/ M ・ h ・ ℃) 、 Mitsui Metal Paint Co., Ltd.
(Sheet material composed of resin composition containing polyurethane resin and thermally expandable graphite, volume expansion coefficient: 4 times, thermal conductivity:
Commercial products such as 0.21 kcal / m · h · ° C.) can be used.

Further, the layer that expands and insulates by heating is preferably formed of the following resin composition (I) or (II). As the resin composition (I), a resin component containing a rubber component or an epoxy resin, neutralized thermally expandable graphite and an inorganic filler are used. As the resin composition (II), What contains a rubber component, a resin component composed of an epoxy resin, a phosphorus compound, neutralized heat-expandable graphite and an inorganic filler is used.

Examples of the rubber component include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and 1,2-polybutadiene rubber (1,2-B
R), styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber (IIR), ethylene-propylene rubber (EPM, E
PDM), chlorosulfonated polyethylene (CSM),
Acrylic rubber (ACM, ANM), epichlorohydrin rubber (CO, ECO), polyvulcanized rubber (T), silicone rubber (Q), fluoro rubber (FKM, FZ), urethane rubber (U) and the like. These rubber components may be used alone or in combination of two or more.

The rubber component may be modified, cross-linked, or the like as long as the fire resistance of the resin composition is not hindered. The method of modification and crosslinking is not particularly limited, and is performed by a known method.

When the above rubber component is used, it is preferable to impart tackiness to facilitate lamination with a fuel tank. The method for imparting tackiness is not particularly limited, and examples thereof include a method in which a liquid resin such as polybutene or a tackifier such as petroleum resin is blended with the rubber component of butyl rubber.

The epoxy resin is not particularly limited, but is basically obtained by reacting a monomer having an epoxy group with a curing agent. Examples of the monomer having an epoxy group include monomers of a bifunctional glycidyl ether type, a glycidyl ester type, and a polyfunctional glycidyl ether type.

Examples of the bifunctional glycidyl ether type monomer include polyethylene glycol type, polypropylene glycol type, neopentyl glycol type, 1,6-hexanediol type, trimethylolpropane type, propylene oxide-bisphenol A type,
Monomers such as hydrogenated bisphenol A type are exemplified.

Examples of the glycidyl ester type monomer include hexahydrophthalic anhydride type, tetrahydrophthalic anhydride type, dimer acid type, and p-oxybenzoic acid type monomers.

Examples of the polyfunctional glycidyl ether type monomer include monomers such as phenol novolak type, orthocresol novolak type, DPP novolak type, and dicyclopentadiene / phenol type.

These monomers having an epoxy group may be used alone or in combination of two or more.

As the curing agent, a polyaddition type or a catalyst type is used. Examples of the polyaddition type curing agent include, for example, polyamines, acid anhydrides, polyphenols, polymercaptans, and the like. As the catalyst type curing agent,
For example, tertiary amines, imidazoles, Lewis acid complexes and the like are exemplified.

The method for curing the epoxy resin is not particularly limited, and can be performed by a known method.

The neutralized heat-expandable graphite is obtained by neutralizing heat-expandable graphite which is a conventionally known substance. The heat-expandable graphite is a natural scale-like graphite, pyrolytic graphite, powder such as quiche graphite,
Produced by treating with inorganic acids such as concentrated sulfuric acid, nitric acid, and selenic acid and strong oxidizing agents such as concentrated nitric acid, perchloric acid, perchlorate, permanganate, dichromate, and hydrogen peroxide. It is a graphite intercalation compound that is a crystalline compound while maintaining a layered structure of carbon.

The heat-expandable graphite obtained by the acid treatment as described above is further neutralized by neutralizing it with ammonia, a lower aliphatic amine, an alkali metal compound, an alkaline earth metal compound or the like. The heat-expandable graphite is used.

The aliphatic lower amine is not particularly restricted but includes, for example, monomethylamine, dimethylamine,
Trimethylamine, ethylamine, propylamine, butylamine and the like. The alkali metal compound and the alkaline earth metal compound are not particularly limited,
For example, hydroxides, oxides, carbonates, sulfates, organic acid salts of potassium, sodium, calcium, barium, magnesium and the like can be mentioned.

The particle size of the neutralized heat-expandable graphite is preferably 20 to 200 mesh. When the particle size is smaller than 200 mesh, the degree of expansion of graphite is small, a predetermined refractory insulation layer cannot be obtained, and when the particle size is larger than 20 mesh, there is an advantage that the degree of expansion of graphite is large,
When kneading with a resin binder, dispersibility deteriorates, and a decrease in physical properties is inevitable.

Commercial products of the above neutralized heat-expandable graphite include, for example, “GREP-EG” manufactured by Tosoh Corporation, U.S. Pat.
"GRAFGUARD" manufactured by CAR CARBON, and the like.

Examples of the inorganic filler include silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, calcium hydroxide, magnesium hydroxide, Aluminum hydroxide, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate,
Barium carbonate, dawsonite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite,
Sericite, glass fiber, glass beads, silica-based balun, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balun,
Charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate, various magnetic powders, slag fiber, fly ash and the like. These may be used alone or in combination of two or more.

Among the above-mentioned inorganic fillers, metal carbonates such as calcium carbonate and zinc carbonate, which play an aggregate role, and aluminum hydroxide, magnesium hydroxide, etc. which give an endothermic effect upon heating in addition to the role of aggregate. Are preferred. It is considered that the combined use of the above-mentioned hydrated inorganic substance and metal carbonate greatly contributes to improvement of the strength of the combustion residue and increase of the heat capacity.

Further, the above-mentioned hydrated inorganic substance is endothermic due to water generated by a dehydration reaction during heating, and the temperature rise is reduced so that high heat resistance is obtained. Also, an oxide remains as a heating residue. This is particularly preferable in that it works as an aggregate to improve the residue strength. Among them, magnesium hydroxide and aluminum hydroxide have different temperature ranges in which the dehydrating effect is exhibited, so when used in combination, the temperature range in which the dehydrating effect is exhibited becomes wider, and a more effective temperature rise suppressing effect is obtained, so that the combination is used. Is preferred.

The inorganic filler has a particle size of 0.5 to
100 μm is preferable, and more preferably, about 1 to 50 μm.
m. In addition, it is more preferable to use a combination of an inorganic filler having a large particle size and a small filler having a small particle size. By using the combination, it is possible to increase the packing while maintaining the mechanical performance of the layer that expands and insulates by heating. It becomes possible.

Commercial products of the above-mentioned hydrated inorganic substances include, for example, aluminum hydroxide, "Hygilite H-42M" having a particle size of 1 μm (manufactured by Showa Denko KK), and "Hygilite H-31" having a particle size of 18 μm (Showa Denko). Denko Corporation) and the like.

Commercially available calcium carbonate products include, for example, "Whiteton SB Red" having a particle size of 1.8 μm (manufactured by Shiraishi Calcium Co., Ltd.) and "Whiteton BF30 having a particle size of 8 μm.
0 "(manufactured by Bihoku Powder Chemical Co., Ltd.) and the like.

Examples of the phosphorus compound include red phosphorus; various phosphates such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate; sodium phosphate, phosphorus Metal phosphates such as potassium acid and magnesium phosphate; ammonium polyphosphates; and compounds represented by the following general formula (1). Among these, from the viewpoint of fire resistance, red phosphorus, ammonium polyphosphates, and compounds represented by the following general formula (1) are preferable, and ammonium polyphosphates are more preferable in terms of performance, safety, cost, and the like. preferable.

[0034]

Embedded image

In the formula, R ¹ and R ³ are hydrogen, C ¹ -C 1
It represents a 16 linear or branched alkyl group or an aryl group having 6 to 16 carbon atoms. R ² is a hydroxyl group, a linear or branched alkyl group having 1 to 16 carbon atoms, a linear or branched alkoxyl group having 1 to 16 carbon atoms,
Represents an aryl group having 6 to 16 carbon atoms or an aryloxy group having 6 to 16 carbon atoms.

The above-mentioned red phosphorus improves the flame-retardant effect by adding a small amount. As the red phosphorus, commercially available red phosphorus can be used, but from the viewpoint of moisture resistance, safety such as not spontaneously igniting during kneading, those obtained by coating the surface of red phosphorus particles with a resin are preferably used. .

The compound represented by the above general formula (1) is not particularly restricted but includes, for example, methylphosphonic acid, dimethyl methylphosphonate, diethyl methylphosphonate, ethylphosphonic acid, propylphosphonic acid, butylphosphonic acid, 2-methylpropyl Phosphonic acid, t-butylphosphonic acid, 2,3-dimethyl-butylphosphonic acid, octylphosphonic acid, phenylphosphonic acid, dioctylphenylphosphonate, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctyl Examples include phosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid, diphenylphosphinic acid, and bis (4-methoxyphenyl) phosphinic acid. Among them, t-butylphosphonic acid is expensive, but is preferable in that it has excellent flame retardancy. The above phosphorus compounds may be used alone or in combination of two or more.

The above ammonium polyphosphates include:
For example, ammonium polyphosphate, melamine-modified ammonium polyphosphate and the like can be mentioned, but ammonium polyphosphate is preferably used from the viewpoint of handleability and the like. As a commercially available product, for example, "Exolit A" manufactured by Clariant
P422 "," Exolit AP462 "," Sumisafe P "manufactured by Sumitomo Chemical Co., Ltd.," Terage C6 "manufactured by Chisso
0, "" Terage C70, "" Terage C80, "and the like.

By using a phosphorus compound in combination with the inorganic filler, the flame retardancy of the layer that expands when heated can be improved. Metal carbonates such as calcium carbonate and zinc carbonate are considered to promote expansion by a reaction with a phosphorus compound. In particular, when ammonium polyphosphate is used as the phosphorus compound, a high expansion effect can be obtained. In addition, it acts as an effective aggregate and forms a residue having high shape retention after burning.

In the resin composition (I), the amount of the neutralized heat-expandable graphite is preferably 15 to 300 parts by weight based on 100 parts by weight of the resin component. If the compounding amount of the heat-expandable graphite is less than 15 parts by weight, sufficient expansion performance cannot be obtained, and if it exceeds 300 parts by weight, the mechanical properties of the layer that expands and is thermally insulated by heating become large and cannot be used. .

In the resin composition (I), the compounding amount of the inorganic filler is 30 to 5 with respect to 100 parts by weight of the resin component.
00 parts by weight is preferred. If the compounding amount is less than 30 parts by weight, sufficient expansion performance cannot be obtained, and if it exceeds 500 parts by weight, the mechanical properties of the layer that expands and is thermally insulated by heating become large and cannot be used.

In the resin composition (I), the total amount of the neutralized heat-expandable graphite and the inorganic filler is as follows:
The amount is preferably 200 to 600 parts by weight based on 100 parts by weight of the resin component. If the total amount is less than 200 parts by weight, sufficient fire resistance cannot be obtained, and if it exceeds 600 parts by weight, the mechanical properties of the layer that expands and is thermally insulated by heating become large, making it unusable for use.

In the above resin composition (II), the blending amount of the neutralized heat-expandable graphite is 15 to 100 parts by weight of the resin component for the same reason as in the resin composition (I).
The amount is preferably 300 parts by weight, and the amount of the inorganic filler is preferably 30 to 500 parts by weight based on 100 parts by weight of the resin component for the same reason as in the resin composition (I).

In the above resin composition (II), the compounding amount of the phosphorus compound is 50 to 1 with respect to 100 parts by weight of the resin component.
50 parts by weight are preferred. If the amount is less than 50 parts by weight, sufficient shape-retaining property cannot be obtained, and if it exceeds 150 parts by weight, the mechanical properties of the layer that expands and insulates when heated are greatly reduced.

In the resin composition (II), the total amount of the phosphorus compound, the neutralized heat-expandable graphite and the inorganic filler is 200 to 6 parts per 100 parts by weight of the resin component.
00 parts by weight is preferred. If the total amount is less than 200 parts by weight, sufficient fire resistance cannot be obtained, and if the total amount exceeds 600 parts by weight, the mechanical properties of the layer that expands and insulates due to heating are greatly reduced.

In particular, the layer which expands and insulates by the above-mentioned heating includes:
When an epoxy resin is used as the resin component, the resin is a thermosetting resin, and thus has excellent heat resistance, and has a cross-linked structure, which is excellent in shape retention of the residue after expansion.

The above-mentioned resin compositions (I) and (II) may contain phenolic, amine-based, sulfur-based antioxidants, metal harm inhibitors, antistatic agents as long as their physical properties are not impaired. Stabilizers, crosslinking agents, lubricants, softeners, pigments and the like may be added.

The above resin composition (I) or (II) is obtained by mixing each component with an extruder, a Banbury mixer, a kneader mixer,
It can be obtained by mixing using a kneading device such as a roll or a stirring device. The resin composition is formed into a sheet by a conventionally known method such as calender molding, extrusion molding, press molding or the like, whereby a layer that expands and is thermally insulated by the above-described heating can be obtained.

The layer which expands and insulates by the above-mentioned heating is coated on the outer surface of the fuel tank. However, since the fuel tank for automobiles is generally mounted in contact with the bottom of the automobile, it is often inflated and insulated by the above-mentioned heating. The layer to be coated only needs to cover at least the lower half outer surface of the fuel tank, and does not necessarily need to cover the entire outer surface of the fuel tank.

When a molded body previously formed into a shape corresponding to the outer surface of the fuel tank by injection molding or the like is used instead of the sheet-like material as the layer that expands and insulates by heating, the layer can be easily mounted. Productivity is improved. In this case, it is preferable to use an epoxy resin as a resin component in consideration of moldability.

(Function) The expansion and heat insulating layer used in the fuel tank of the present invention is formed from a resin composition containing a resin component, neutralized heat-expandable graphite and an inorganic filler, thereby causing a fire. Due to the heating, the resin component is carbonized to serve as a heat insulating layer, and the heat-expandable graphite forms an expanded heat-insulating layer to prevent heat from being transmitted to the fuel tank. Further, the inorganic filler contributes to an increase in heat capacity. Further, the addition of the phosphorus compound to the resin composition improves the shape retention of the expanded heat insulating layer and the filler.

[0052]

Embodiments of the present invention will be described below.

(Examples 1 to 3, Comparative Examples 1 to 3) Resin components in the amounts shown in Table 1, neutralized heat-expandable graphite,
The inorganic filler and the phosphorus compound were kneaded with a roll to obtain a resin composition. Next, when the resin component of the resin composition was a rubber component, the resin composition was press-molded at 100 ° C. for 3 minutes to prepare a test piece A used for fire resistance evaluation. Further, when the resin component of the resin composition was an epoxy resin, the resin composition was press-molded at 150 ° C. for 15 minutes and cured to prepare a test piece A used for fire resistance evaluation.

Separately, a high-density polyethylene (“SHOLEX 4551H” manufactured by Showa Denko KK) was used, and the length was 100 mm.
× After preparing a test piece B having a width of 100 mm and a thickness of 3 mm,
The test piece A was laminated on the test piece B to obtain a test piece for evaluating fire resistance of a fuel tank. After the test piece was fixed so that the test piece A side was on the lower side, a Bunsen burner was placed below the test piece, and the sample was heated so that the tip of the flame of the Bunsen burner was in contact with the test piece A. In the table, ○ indicates that the test piece B was not opened by heating for 60 seconds, and X indicates that the test piece B was opened by heating for less than 60 seconds. The Bunsen burner flame was adjusted so that the height of the flame was 3 cm and the temperature of the flame tip was 800 ° C.

[0055]

[Table 1]

The components used in the table are as follows. -Butyl rubber: Exxon butyl 06 manufactured by Exxon Chemical
・ Polybutene: "Idemitsu Polybutene 10" manufactured by Idemitsu Petrochemical Co., Ltd.
0R "・ Petroleum resin:“ Escolets 532 ”manufactured by Tonex
0 "

A monomer having an epoxy group (indicated by an epoxy monomer in the table): "Epicoat E807" (Bisphenol F type epoxy monomer) manufactured by Yuka Shell Epoxy Co., Ltd. "Epicoat YL6795" (Bisphenol F type) manufactured by Yuka Shell Epoxy Co. Epoxy monomer) ・ Curing agent: “Epicure F” manufactured by Yuka Shell Epoxy
L052 ”(Diamine-based curing agent)“ Epicure YLH85 ”manufactured by Yuka Shell Epoxy
4 "(diamine-based curing agent)

-Neutralized heat-expandable graphite: "Frame Cut GREP-EG" manufactured by Tosoh Corporation-Aluminum hydroxide: "Heidilite H-" manufactured by Showa Denko KK
31 ”・ Calcium carbonate:“ Whiteton BF-3 ”manufactured by Bihoku Powder Chemical Co., Ltd.
00 "-Ammonium polyphosphate:" Exolit AP422 "manufactured by Clariant

[0059]

The fuel tank of the present invention has the above-described structure, has high flame retardancy, and has excellent fire protection performance in the event of fire by forming a refractory heat insulating layer by expanding the residue after heating. To prevent combustion of the fuel tank. Further, even if a heat generation source such as an exhaust pipe or an exhaust gas purification device is arranged near the fuel tank, the fire prevention performance does not decrease.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 21/00 C08L 63/00 C 63/00 F02M 37/00 301J F02M 37/00 301 B60K 15/02 A F term (reference) 3D038 CA08 CA11 CB01 CC20 4J002 AC011 AC031 AC061 AC071 AC081 AC091 BB151 BB181 BB271 BD121 BG041 CD011 CD031 CD051 CD061 CD091 CD101 CH041 CK021 CP031 DA017 DA026 DA058 DA067 DE007 DE247DE077 DG 147 EW048 EW128 EW138 FA047 FA087 FA107 FB076 FB086 FB268 FD017 FD136 FD137 FD138 FD140 GH00 GN00

Claims (5)

[Claims] 1. A fuel tank comprising: a fuel tank main body formed of a synthetic resin; and a layer that expands and insulates by heating on at least an outer surface of a lower half of the fuel tank main body. 2. A layer which expands and is thermally insulated by heating is composed of 100 parts by weight of a resin component composed of a rubber component or an epoxy resin, 15 to 300 parts by weight of neutralized thermally expandable graphite, and
The total amount of the heat-expandable graphite and the inorganic filler formed from the resin composition (I) containing 30 to 500 parts by weight of the inorganic filler and subjected to the neutralization treatment is 200 to 600 parts by weight. The fuel tank according to claim 1, wherein 3. A layer which expands and is thermally insulated by heating is composed of 100 parts by weight of a resin component composed of a rubber component or an epoxy resin, 50 to 150 parts by weight of a phosphorus compound, 15 to 300 parts by weight of neutralized thermally expandable graphite, and , Inorganic filler 30-50
The total amount of the heat-expandable graphite, the inorganic filler and the phosphorus compound formed from the resin composition (II) containing 0 parts by weight and neutralized is 200 to 600 parts by weight. Item 7. The fuel tank according to Item 1. 4. The fuel tank according to claim 2, wherein the inorganic filler is a hydrated inorganic substance and / or an inorganic carbonate. 5. The fuel tank according to claim 1, wherein the layer that expands and insulates by heating is formed of a molded body.