JP2001348017A - Manufacturing method of fuel container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an economic fuel container having excellent melting formability and mechanical properties. SOLUTION: A re-grind layer is formed of the ground stuff of a laminate body comprising an intermediate layer formed of the ethylene-vinyl acetate copolymer saponified product containing at least one kind selected among magnesium, calcium and zinc with the total content of 10-500 ppm, and a thermoplastic resin layer laminated on at least both outermost layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fuel container using a laminate having an intermediate layer of a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH). The present invention relates to a method for manufacturing a fuel container having excellent moldability and mechanical properties.

[0002]

2. Description of the Related Art In general, EVOH is excellent in transparency, antistatic property, oil resistance, solvent resistance, gas barrier property, fragrance retention property and the like.
Polyethylene, polypropylene on both sides of the VOH layer,
By laminating layers of nylon, polyester, etc., while maintaining the properties of EVOH such as gas barrier properties, aroma retention properties, and prevention of food discoloration, drop strength, thermoformability,
The fact is that EVOH is used for various packaging applications by compensating for the drawbacks of EVOH such as moisture proofness. In recent years, it has been used not only for food packaging as described above, but also for containers such as bottles, tanks, and drums for transporting, storing, and storing fuels mainly composed of hydrocarbons.

When such a multilayer bottle or a multilayer tank is manufactured by blow molding, generally about 30 to 50% of scraps and burrs are generated, so that recycling thereof is economically indispensable. Therefore, in general, it is necessary to provide a layer (regrind layer) for crushing and reusing the scraps or burrs in such multilayer bottles and multilayer tanks for use.

[0004] Such a regrind layer is a mixture of at least a thermoplastic resin such as polyethylene and EVOH. In general, a thermoplastic resin such as polyethylene and EVO are used.
Since the compatibility with H is poor, the moldability of a container such as a multilayer bottle or a multilayer tank containing the obtained regrind layer is deteriorated due to unevenness in the thickness of the regrind layer or a decrease in strength (such as poor appearance). ) And mechanical properties (low temperature impact resistance, etc.)
May be reduced. Therefore, conventionally, the regrind layer is mixed with an appropriate amount of the above-mentioned scrap or burr and a thermoplastic resin such as unused polyethylene to reduce the EVOH content in the regrind layer to reduce the above-mentioned problems. Therefore, it was hard to say that it was economically useful.

To solve such a problem, Japanese Patent Application Laid-Open No. Hei 8-
Japanese Patent Application Laid-Open No. H11-342569 discloses a multilayer hollow molded article (vehicle fuel tank) in which a polyethylene layer contains a polyethylene modified with an unsaturated carboxylic acid or an anhydride thereof and an inorganic filler. ,
Specific polyethylene resin and specific adhesive resin and EVOH
Impact strength of a resin composition composed of 100 J /
m or more (e.g., gasoline tanks for automobiles).

[0006]

However, JP-A-8-85174 and JP-A-11-342569.
In the technique described in Japanese Patent Application Laid-Open Publication No. H10-157, after the scraps and burrs are crushed, re-pelletizing is performed using a melt kneader such as a single screw extruder or a twin screw extruder, and then used for a regrind layer of a blow molding machine. , And there is still room for improvement in terms of economy. With the expansion of the market for such fuel containers, productivity has also been emphasized, and there is a strong demand for a method of manufacturing fuel containers that are economical and have good quality (melt moldability, mechanical properties, etc.). .

[0007]

Therefore, the present inventor has conducted intensive studies in view of the present situation, and as a result, has found that the present invention contains at least one selected from magnesium, calcium, and zinc, and the total content thereof is 10%. E at ~ 500 ppm
It has been found that a method for producing a fuel container using a ground product of a laminate in which VOH is used as an intermediate layer and a thermoplastic resin is laminated on at least both outermost layers for a regrind layer achieves the above object, and completes the present invention. Reached.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
EVOH used for the regrind layer of the present invention, that is, EVOH used for the intermediate layer of the laminate for obtaining the pulverized material
Although there is no particular limitation, EVOH that is the same as or similar to the intermediate layer of the target molded product (in the present invention, the fuel container) is usually used. Mol% (more preferably 10 to 34 mol%, particularly 15 to 28 mol%). When the ethylene content is less than 10 mol%, the low-temperature impact resistance and the melt moldability tend to decrease, Conversely, 60 mol%
If it exceeds, sufficient barrier properties against fuel cannot be obtained, which is not preferable.

The degree of saponification and the melt flow rate (MFR) of the EVOH are not particularly limited. However, in view of the above-mentioned situation, the degree of saponification is 95 mol% or more (more preferably 99 mol% or more, particularly Is preferably 99.5 mol%). If the saponification degree is less than 95 mol%, sufficient barrier properties against fuel may not be obtained, which is not preferable.

The EVOH melt flow rate (M
FR) (210 ° C., load 2160 g) is 0.1 to 20
g / 10 minutes (further 1 to 10 g / 10 minutes, especially 2 to 6
g / 10 minutes), and when the melt flow rate is smaller than the range, the inside of the extruder may be in a high torque state at the time of molding the fuel container, and the extrusion may be difficult. Is too large, the mechanical strength of the fuel container may be insufficient.

The EVOH is obtained by saponifying an ethylene-vinyl acetate copolymer, and the ethylene-vinyl acetate copolymer can be produced by any known polymerization method, for example, solution polymerization,
It is produced by suspension polymerization, emulsion polymerization, or the like, and saponification of an ethylene-vinyl acetate copolymer can also be performed by a known method.

In the present invention, a copolymerizable ethylenically unsaturated monomer may be copolymerized within a range not to impair the effects of the present invention (about 10 mol% or less). Are olefins such as propylene, 1-butene and isobutene, acrylic acid, methacrylic acid, crotonic acid, (phthalic anhydride), maleic anhydride, and anhydrous anhydride.
Unsaturated acids such as itaconic acid or salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, N-alkylacrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or Acrylamides such as salts thereof, acrylamidopropyldimethylamine or its salts or quaternary salts, methacrylamide, C-C18 N-alkylmethacrylamide, N, N
-Dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or a salt thereof or 4
Methacrylamides such as grade salts, N-vinylpyrrolidone,
N-vinylamides such as N-vinylformamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl ethers such as alkyl vinyl ether having 1 to 18 carbon atoms, hydroxyalkyl vinyl ether and alkoxyalkyl vinyl ether; Vinyl, vinylidene chloride, vinyl fluoride,
Vinyl halides such as vinylidene fluoride and vinyl bromide, vinyl silanes such as trimethoxy vinyl silane, allyl acetate, allyl chloride, allyl alcohol, dimethyl allyl alcohol, trimethyl- (3-acrylamide-
3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like. Further, post-modification such as urethanization, acetalization, cyanoethylation, etc. may be performed as long as the gist of the present invention is not impaired.

In the present invention, the EVOH contains at least one selected from the group consisting of magnesium, calcium, and zinc, and the total content thereof is 10 to 500 ppm (more preferably 50 to 400 ppm, particularly 100 to 300 pp).
m) is essential, and if this is not satisfied, it is not possible to manufacture a fuel container having excellent melt moldability and mechanical properties, which are the objects of the present invention. That is, when the total content of at least one selected from the group consisting of magnesium, calcium, and zinc is out of the above range, the melt-moldability and mechanical properties of the regrind layer of the fuel container are reduced. Cannot be achieved.

When at least one selected from the group consisting of magnesium, calcium and zinc is contained in EVOH, acetic acid, propionic acid, butyric acid, lauric acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid Organic acids such as stearic acid, basic stearic acid, hydroxystearic acid, basic hydroxystearic acid, nonadecanoic acid, oleic acid, capric acid, behenic acid, montanic acid, linoleic acid, adipic acid, sulfuric acid, sulfurous acid, carbonic acid , Boric acid, phosphoric acid, and the like, and metal salts of acetic acid, stearic acid, and hydroxystearic acid are particularly preferably used because of their excellent effects.

In the present invention, as described above, EVOH contains at least one selected from magnesium, calcium, and zinc. However, considering the productivity of EVOH, any one of magnesium, calcium, and zinc may be used. A seed may be contained. At this time, the content is 10 to 500 ppm (further, 50 to 400 ppm,
In particular, 100 to 300 ppm). When the quality of the fuel container (melt moldability, mechanical properties, etc.) is considered as the highest priority, it is preferable to simultaneously contain at least two types of magnesium, calcium, and zinc. Is 5 to 400 ppm (further 20 to 300 ppm, especially 50 to 250 ppm)
In each content ratio, the content of the minimum compound is 5% by weight or more (more preferably 10% by weight or more, particularly 1% by weight or more).
5% by weight or more) is preferable, and when the content ratio is out of the above range, the effect of including at least two kinds in combination is poor, which is not preferable.

As a method for incorporating at least one selected from magnesium, calcium and zinc into EVOH, a) a porous precipitate of EVOH having a water content of 20 to 80% by weight is prepared by removing at least one selected from magnesium, calcium and zinc. A method of contacting with an aqueous solution of one kind (salt) to contain the metal (salt) and then drying; a) a homogeneous EVOH solution (water / alcohol solution or the like) at least selected from magnesium, calcium, and zinc After containing one kind (salt), it is extruded in the form of a strand into a coagulating liquid, and then the obtained strand is cut into pellets and further subjected to a drying treatment. C) From EVOH and magnesium, calcium, zinc A method in which at least one (salt) selected is collectively mixed and then melt-kneaded with an extruder or the like may be mentioned. Kill. When the metal (salt) is water-soluble, the method (a) which is excellent in dispersibility and productivity of the metal (salt) is preferable. When the metal (salt) is insoluble in water, the method (c) is excellent in productivity. A method is preferred, and such a method is described in more detail, but is not limited thereto.

In making the EVOH contain at least one (salt) selected from the group consisting of water-soluble magnesium, calcium, and zinc (the above method (a)), at least one (salt) selected from magnesium, calcium, and zinc is used. ) Can be contained by bringing EVOH into contact with the aqueous solution, and the concentration of at least one (salt) selected from magnesium, calcium, and zinc in the aqueous solution is 0.001 to 10% by weight ( Moreover 0.005-
1% by weight, particularly 0.01 to 0.5% by weight), and less than 0.001% by weight, a predetermined amount of magnesium,
It may be difficult to contain at least one selected from calcium and zinc. Conversely, if it exceeds 10% by weight, the moldability of the fuel container may decrease, which is not preferable.

The method of bringing EVOH into contact with such an aqueous solution is not particularly limited. Usually, at least one of the above-mentioned magnesium, calcium, and zinc is added to the aqueous solution while stirring the EVOH formed into pellets and stirring. It is preferable to include a seed (salt). still,
In preparing (molding) the above EVOH pellets,
A known method can be adopted.For example, after extruding a mixed solution of EVOH water and alcohol into a coagulating liquid into a strand or a sheet, the obtained strand or sheet is cut into pellets. Good. As the shape of such a pellet-like EVOH, a columnar shape, a spherical shape, or the like is preferable. In the case of a columnar shape, the diameter is 1 to 10 mm,
The length is preferably 1 to 10 mm.
10 to 10 mm is preferred.

The EVOH has a diameter of 0.1-1.
Those having a microporous internal structure in which pores of about 0 μm are uniformly distributed are preferable in that they can uniformly contain at least one (salt) selected from magnesium, calcium, and zinc. Water / alcohol mixed solvent) into the coagulation bath when EVOH
Solution concentration (20-80% by weight), extrusion temperature (45
~ 70 ° C), solvent type (water / alcohol mixture weight ratio =
90/10 to 10/90 etc.), the temperature of the coagulation bath (0 to 20)
C), the residence time (0.25 to 30 hours), the amount of EVOH in the coagulation bath (0.02 to 2% by weight), and the like can be arbitrarily adjusted to obtain an EVOH having the structure. .
Further, those having a water content of 20 to 80% by weight are preferable because the metal (salt) can be uniformly and rapidly contained. In adjusting the content of at least one (salt) selected from magnesium, calcium, and zinc, there is no particular limitation. In the contact treatment with the above-described aqueous solution, at least one selected from magnesium, calcium, and zinc is used. Aqueous solution concentration of (salt), contact treatment time,
Contact treatment temperature, stirring speed during contact treatment, and EV to be treated
It is possible by controlling the water content of OH and the like.

Thus, a pellet-shaped hydrous EVOH containing at least one (salt) selected from magnesium, calcium and zinc can be obtained. Usually, after the above-mentioned contact treatment, a drying step is carried out, followed by a drying step. EVOH used for the liglide layer (hereinafter sometimes referred to as M-EVOH), that is, EVOH used for the intermediate layer of the laminate for obtaining the pulverized product is obtained.

As such a drying method, various drying methods can be adopted. For example, fluidized drying is performed while EVOH substantially in the form of pellets is stirred or dispersed mechanically or by hot air, or EVOH substantially in the form of pellets is not given dynamic action such as stirring and dispersion. Stationary drying is performed. Examples of a dryer for performing fluidized drying include a cylindrical / groove type stirring dryer, a cylindrical dryer, a rotary dryer, a fluidized bed dryer, a vibration fluidized bed dryer, and a conical rotary dryer. Examples of the dryer include a batch-type box dryer as a material stationary type, and a band dryer, a tunnel dryer, and a vertical dryer as a material transfer type. And the like, but are not limited thereto. It is also possible to combine fluidized drying and standing drying.

Air or an inert gas (nitrogen gas, helium gas, argon gas, etc.) is used as a heating gas used in the drying process. The temperature of the heating gas is 40 to 150 ° C. It is preferable from the viewpoint of preventing thermal degradation of EVOH. The time of the drying treatment is EVOH
15 minutes to 72 minutes, depending on the water content of
A time period is preferable in terms of productivity and prevention of thermal degradation of EVOH.

The EVOH is dried under the above conditions,
The desired EVOH is obtained, and the moisture content of the EVOH after the drying treatment is 0.001 to 1% by weight (further, 0.01 to 0.5% by weight, particularly 0.1 to 0.3% by weight). % By weight), and the water content is 0.0
If the amount is less than 01% by weight, the melt moldability of the fuel container may decrease, while if it exceeds 1% by weight, foaming is likely to occur during molding of the fuel container, which is not preferable.

The water content of EVOH referred to here is measured and calculated by the following method. [Method of Measuring Water Content] Weigh EVOH with an electronic balance (W
1: unit g), put in a hot-air oven type drier maintained at 150 ° C., dried for 5 hours, and further allowed to cool in a desiccator for 30 minutes.
2: unit g) and calculate from the following equation (1).

Water content (%) = {(W 1 −W 2) / W 1} × 100 (1)

When the EVOH contains at least one (salt) selected from water-insoluble magnesium, calcium, and zinc (the method (c) above),
VOH and at least one (salt) selected from magnesium, calcium, and zinc are mixed and kneaded. As a means, for example, a known method such as a kneader ruder, an extruder, a mixing roll, a Banbury mixer, a plast mill, or the like is used. And usually performed at 150 to 300 ° C. (further 180 to 280 ° C.).
C), it is preferable to melt and knead for about 1 to 20 minutes, and it is industrially advantageous in that pellets can be easily obtained by using a single-screw or twin-screw extruder, and if necessary, It is also preferable to provide a vent suction device, a gear pump device, a screen device, and the like. In particular, an extruder is used to remove water and by-products (such as low-molecular weight pyrolysis products).
By providing at least one vent hole and sucking under reduced pressure, or by continuously supplying an inert gas such as nitrogen into the hopper to prevent mixing of oxygen into the extruder, thermal coloring and An M-EVOH of excellent quality with reduced thermal degradation can be obtained.

The supply method is not particularly limited either. 1) A method in which EVOH and at least one (salt) selected from magnesium, calcium, and zinc are dry-blended and collectively supplied to an extruder. 2) A method of supplying at least one (salt) of solid magnesium, calcium, and zinc to a place where EVOH is supplied to an extruder and melted (solid side feed method);
3) A method in which at least one salt selected from magnesium, calcium, and zinc is supplied (melt side feed method) to the place where EVOH is supplied to an extruder and melted, may be mentioned. Among them, 1)
This method is practical in terms of simplicity and cost of the apparatus.

Under the above conditions, EVOH and at least one (salt) selected from magnesium, calcium, and zinc are melt-kneaded to obtain a desired EVOH. The water content of the EVOH after the melt-kneading is obtained. Is 0.001
1% by weight (further 0.01 to 0.5% by weight, especially 0.1 to 0.5% by weight).
When the water content is less than 0.001% by weight, the melt formability of the fuel container may be reduced. Foaming is likely to occur during molding of the fuel container, which is not preferable. The water content of EVOH referred to here is measured and calculated by the above-described method.

Thus, the desired EVOH can be obtained. In the present invention, the acids (acetic acid, boric acid, phosphoric acid, etc.) and the alkali metals (sodium, potassium, etc.) are used within a range not to impair the object of the present invention. ), Metal salts of alkaline earth metals (excluding magnesium and calcium), transition metals and the like (excluding zinc), saturated aliphatic amides (eg, stearic acid amide), unsaturated fatty acid amides (eg, oleic acid amide), Bis fatty acid amides (eg, ethylene bis stearic acid amide, etc.), fatty acid metal salts (excluding magnesium salts, calcium salts, and zinc salts), low molecular weight polyolefins (eg, having a molecular weight of 500 to 10,000)
Lubricants such as low molecular weight polyethylene or low molecular weight polypropylene, inorganic salts (such as hydrotalcite), plasticizers (such as aliphatic polyhydric alcohols such as ethylene glycol, glycerin and hexanediol), and antioxidants , An ultraviolet absorber, an oxygen absorber, a crystal nucleating agent, a coloring agent, an antistatic agent, a surfactant, a drying agent, an antibacterial agent, an antiblocking agent (for example, talc fine particles, etc.),
Slip agent (for example, amorphous silica, etc.), filler (for example, inorganic filler, etc.), other resin (for example, polyolefin, polyamide, etc.), other EVOH (EVOH with different ethylene content, saponification degree, MFR, etc.) are compounded. You may.

Next, the thermoplastic resin used for the regrind layer, that is, the thermoplastic resin used for both outermost layers of the laminate for obtaining the pulverized product is not particularly limited, and linear low-density polyethylene, Low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-acrylate copolymer, polypropylene, propylene-α-olefin (Α-olefin having 4 to 20 carbon atoms) Copolymer, homo- or copolymer of olefin such as polybutene, polypentene, or homo- or copolymer of these olefins was graft-modified with unsaturated carboxylic acid or ester thereof. Things such as polyolefin-based resins, polyesters, polyamides, Copolyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene,
Chlorinated polypropylene, aromatic or aliphatic polyketones, polyalcohols obtained by further reducing these,
Further, other EVOHs and the like can be mentioned.
Similarly to the above, high density polyethylene (HDPE) is preferably used in consideration of the required performance (moldability, strength, etc.) of both outermost layers of the molded product. In the present invention, the above-mentioned various additives, modifiers, other resins, and the like may be added to such a thermoplastic resin as long as the object of the present invention is not impaired.

The present invention is characterized in that a pulverized product of a laminate using EVOH and a thermoplastic resin as described above is used for a liglide layer, and a method for manufacturing a fuel container using such a regrind layer is specifically described. Will be explained. still,
For the laminate for obtaining the pulverized material used for the regrind layer, it is general to use a fuel container obtainable by the method of the present invention. This method will be described, but the method of the present invention is not limited to this method. It is not something to be done. That is, a pulverized product of another fuel container (two or more types of containers may be used) made of a laminate using EVOH or a thermoplastic resin satisfying the conditions of the present invention is used for the liglide layer. It is also possible to use a mixture of the crushed material and the crushed material of the fuel container (laminate) obtained by the method of the present invention for the regrind layer.

The present invention relates to a method for producing a fuel container which is used as a regrind layer by using a pulverized product of a laminate having at least a thermoplastic resin layer / M-EVOH layer / thermoplastic resin layer. In producing such a laminate, M-EVOH and a thermoplastic resin are supplied to an injection molding machine, a direct blow molding machine (continuous type, accumulator type), an injection blow molding machine, or the like, and directly subjected to the multilayer of the present invention. In addition to the method of obtaining a fuel container, M-EV
A method of vacuum forming a multilayer sheet obtained by co-extrusion of OH and a thermoplastic resin, M-EV on a thermoplastic resin film
A method of vacuum forming a laminated sheet obtained by co-extrusion of OH / thermoplastic resin, a thermoplastic resin film and M-
Examples include a method of vacuum forming a multilayer sheet obtained by dry laminating an EVOH film using an adhesive, and preferably a direct blow molding (a continuous type, an accumulator type) in which a large amount of scraps and burrs are generated. )
Useful for methods. For example, the parison obtained by co-extrusion of M-EVOH and a thermoplastic resin is sandwiched between molds and blown by blowing air to obtain the laminate.

[0033] Scraps and burrs generated during the production of the laminate by blow molding or the like are then pulverized, and the pulverized material is used as a regrind layer of a fuel container.
The grinding of such scraps and burrs can be performed by using a known grinding machine. The shape and particle size of such a pulverized product are not particularly limited, but the apparent density thereof is 0.25 to 0.55 g / cc (further, the apparent density is 0.2 to 0.55 g / cc).
3 to 0.5 g / cc, especially 0.35 to 0.45 g / c
c) is preferred in that the melt formability and mechanical properties of the regrind layer of the obtained fuel container are further improved, and when the apparent density is less than 0.3 g / cc, poor supply of the extruder occurs. The melt moldability of the regrind layer of the fuel container may be reduced due to the
If the value exceeds c, the dispersion of EVOH in the regrind layer becomes poor, and the melt moldability and mechanical properties of the regrind layer of the fuel container may undesirably decrease. Such apparent density can be controlled by arbitrarily adjusting the shape of the crushing blade of the crusher, the number of revolutions of the crushing blade, the processing speed of the crushing, the size of the mesh opening used, and the like. . In addition, the apparent density here is a value measured based on the "5.3 Apparent density" test method of JIS-K6891.

In this way, a pulverized product of the laminate is obtained. The pulverized product can be directly supplied to an extruder for a regrind layer of a fuel container, or can be prepared in advance by a single-screw extruder or a twin-screw extruder. After re-pelletization using a melt kneader such as a mixer, it is also possible to supply to the extruder for the regrind layer of the fuel container, but in the present invention, such pulverized material is directly used for the fuel container. Even if it is supplied to an extruder for a regrind layer, it is preferable because it has excellent melt moldability and mechanical properties and is advantageous in terms of productivity (economical efficiency). In addition, all of the pulverized product of such a laminate can be supplied to an extruder for a regrind layer, or an unused amount of the same thermoplastic resin or a different thermoplastic resin can be mixed in an appropriate amount and supplied to the extruder. Although it is possible, in the present invention, even if all of such pulverized materials are supplied to an extruder for a regrind layer of a fuel container, the extruders are excellent in melt moldability and mechanical properties, and in terms of productivity (economic efficiency). Is preferred because it is advantageous.

Since the religion layer of the present invention contains at least one selected from magnesium, calcium and zinc in the EVOH, the dispersion of the EVOH is improved by melt-kneading the pulverized material in advance as in the prior art. It is a major feature of the present invention that there is no particular need to control the content of EVOH in the composition for the regrind layer, by adding unused polyethylene or the like to the pulverized product of the laminate. is there.

In molding the fuel container, the same molding method as that for the above-mentioned laminate can be used, and preferably, a direct blow molding (continuous or accumulator type) method having excellent productivity is used. . The extruder for the regrind layer used for such molding is not particularly limited, but has an inner diameter of 20 mm or more (more preferably 30 to 150 mm).
mm, especially 40 to 120 mm), and when the inside diameter is less than 20 mm, productivity is poor, which is not preferred. L / D is 20 to 80 (furthermore, 25 to 60,
In particular, 30 to 40) is preferable, and the L / D diameter is 20
If it is less than 80, the ability of the melt-kneading of the pulverized material may be insufficient. On the other hand, if it exceeds 80, the residence time of the pulverized material (resin composition) in the extruder becomes unnecessarily long, which may cause thermal deterioration. Preferably, the compression ratio of the screw is preferably 2 to 5 (more preferably 2.5 to 4.5, particularly 3 to 4). If the compression ratio is less than 2, the ability of melt-kneading the pulverized material is insufficient. On the contrary, if it exceeds 5, the pulverized material (resin composition) may be undesirably deteriorated by heat.

The temperature (resin temperature) of the pulverized product (resin composition) in the extruder is 150 to 300 ° C. (further 180 ° C.).
It is also preferable to adjust the extrusion conditions (set temperature, screw shape, screw rotation speed, etc.) so that the temperature of the pulverized material becomes lower than 150 ° C. On the other hand, when the temperature exceeds 300 ° C., thermal deterioration of the pulverized product (resin composition) is feared, which is not preferable. The screw rotation speed is 10 to 300 rpm.
(Furthermore, 15 to 200 rpm, especially 20 to 100 rpm
If the number of rotations is less than 10 rpm, the ability to melt and knead the pulverized material may be insufficient, and if it exceeds 300 rpm, thermal degradation of the pulverized material (resin composition) may be caused. Not preferred. Also, if necessary, a vent suction device, a gear pump device, a screen device, etc. may be provided, a screw provided with a known mixing zone such as dalmage, or an inert gas such as nitrogen may be continuously supplied into the hopper. Is also preferable.

In the present invention, the above-mentioned various additives, modifiers, other resins and the like may be added to the pulverized product of the laminate as long as the object of the present invention is not impaired. In particular, saturated aliphatic amides (eg, stearic acid amide, etc.), unsaturated fatty acid amides (eg, oleic acid amide, etc.), bisfatty acid amides (eg, ethylene bisstearic acid amide, etc.), low molecular weight polyolefins (eg, molecular weight 500 to 10,000) Low molecular weight polyethylene,
Or low-molecular-weight polypropylene, etc.), inorganic salts (for example, Kyowa Chemical Co., Ltd. hydrotalcite compound "DH
T-4A "and the hydrotalcite-converted solid solution" ZHT-
4A ”) and antioxidants (eg, hindered phenol“ Irganox 1010 ”,“ Irganox 1098 ”, etc., manufactured by Ciba Specialty Chemicals) and the like can be used in an amount of 100 parts by weight of the pulverized product of the laminate. 0.001 to 1 part by weight (further 0.01 to 0.
5 parts by weight).

Thus, a fuel container in which the pulverized product of the laminate is used as a regrind layer is manufactured. The layer configuration of such a fuel container is as follows. The M-EVOH layer is a, the thermoplastic resin layer is b, the regrind layer is b. Is R, not only the layer configuration of R / a, but also b / R / a, R / b / a, R / a /
R, b / a / R, b / R / a / R, b / R / a / b, b
/ R / a / R / b, b / a / R / a / b, b / R / a /
R / a / R / b and the like can be used, and b / R / a / b and b / R / a are preferable in that the quality (melt moldability and mechanical properties) of the obtained fuel container is excellent. The layer structure of / R / b is employed, and the mixture used in the regrind layer and the adhesive resin described later can be blended into b of these layer structures as needed. Further, in these laminates, an adhesive resin is used between the layers (particularly, the interface of a) as necessary.

Examples of the adhesive resin include a carboxylic acid obtained by chemically bonding an unsaturated carboxylic acid or an anhydride thereof to an olefin polymer (the above-mentioned polyolefin resin in a broad sense) by an addition reaction, a graft reaction or the like. Examples include a modified olefin polymer containing a group,
Specifically, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block or random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, anhydride One or a mixture of two or more selected from maleic acid graft-modified ethylene-vinyl acetate copolymers is preferred. At this time, the amount of the unsaturated carboxylic acid or the anhydride thereof contained in the olefin-based polymer is 0.
001 to 3% by weight (more preferably 0.01 to 1% by weight, particularly 0.03 to 0.5% by weight). In some cases, the properties and impact resistance may be insufficient. On the other hand, when the content is too large, a crosslinking reaction may occur, and the moldability may deteriorate, which is not preferable. In addition, these acid-modified olefin polymers include M
It is also possible to blend a rubber / elastomer component such as EVOH or other EVOH, polyisobutylene, ethylene-propylene rubber, and other thermoplastic resins. In particular, by blending an olefin polymer different from the parent olefin polymer of the acid-modified olefin polymer, the adhesiveness may be improved, which is useful.

The thickness of each layer cannot be specified unconditionally depending on the use, the form of the container and the required physical properties. For example, when used for a fuel tank of an automobile, a is 3
0 to 500 μm (more preferably 50 to 400 μm, especially 80
３００300 μm), b is 100 to 10000 μm (further 200 to 5000 μm, especially 300 to 3000 μm)
And R is 100 to 10000 μm (and even 20 μm).
0 to 5000 μm, especially 300 to 3000 μm), and the adhesive resin layer has a thickness of 30 to 500 μm (more preferably 50 to 400 μm).
m, especially about 80 to 300 μm), and the entire thickness of the fuel container is 300 to 10000 μm (further 1000 to 1000 μm).
8000 μm, especially 2000 to 6000 μm). In particular, the fact that a (M-EVOH layer) is located at a position of 20 to 60% (more preferably 25 to 55%, particularly 30 to 45%) from the inside to the outside in the thickness direction indicates a barrier property of fuel, static It is preferable in that it has excellent crack resistance during deformation, long-term interlayer adhesion, and the like.

Thus, the method for producing a fuel container according to the present invention comprises:
It has excellent melt moldability, mechanical properties, and economic efficiency of fuel containers.
Fuel containers for motorcycles, ships, aircraft, generators, industrial and agricultural equipment, portable containers for replenishing these fuels, and bottles, tanks, drums, etc. for transporting, storing and storing these fuels It is useful as a method for manufacturing various containers. Examples of the fuel include gasoline, particularly gasoline containing a compound containing an oxygen element such as methyl alcohol, ethyl alcohol, and methyl tertiary butyl ether (MTBE), as well as heavy oil, light oil, kerosene, and other fuels.

[0043]

The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

When measuring the contents of magnesium, calcium, and zinc, a dried sample was precisely weighed,
Put in a constant weight platinum evaporating dish, carbonize with an electric heater, then heat with a gas burner, bake until smoke disappears, put the platinum evaporating dish in an electric furnace, raise the temperature, complete ash After cooling, add hydrochloric acid and pure water to the ash, dissolve by heating with an electric heater, pour into a volumetric flask, make the volume constant with pure water, and use it as a sample for atomic absorption analysis. Was measured by

Example 1 EVOH [ethylene content 23 mol%, saponification degree 99.
6 mol%, MFR 2.7 g / 10 min (210 ° C., load 2
160 g)] water / methanol (water / methanol = 70)
/ 30 mixture weight ratio) solution (60 ° C, EVOH concentration 40
%) Was extruded into a water tank maintained at 5 ° C. in the form of a strand and solidified, and then cut with a cutter to obtain a pellet-shaped (diameter 4 mm, length 4 mm) EVOH coagulated product. The mixture was poured into warm water at 30 ° C. and stirred for about 4 hours to obtain a porous precipitate having a water content of 50%.

Next, 100 parts of the obtained porous precipitate was added to 200 parts of a 0.14% aqueous magnesium acetate solution, and the mixture was stirred at 30 ° C. for 5 hours to remove 10 parts of magnesium acetate.
A water-containing EVOH containing 70 ppm was obtained. Using the batch-type fluidized bed dryer, the water-containing EVOH obtained above was treated with
Drying was carried out for about 3 hours while flowing nitrogen gas at 5 ° C. to make the water content 20%, and then dried with nitrogen gas at 125 ° C. for about 18 hours using a batch-type ventilated box dryer. To obtain M-EVOH [containing 180 ppm of magnesium] having a water content of 0.25%.

Next, the obtained M-EVOH and a thermoplastic resin (high-density polyethylene, “HB2” manufactured by Nippon Polychem Co., Ltd.)
14R ") and an adhesive resin (maleic anhydride-modified linear low-density polyethylene," M572 "manufactured by Mitsubishi Chemical Corporation)
Is supplied to a 4-type 6-layer co-extrusion multilayer direct blow apparatus, and [outside] high-density polyethylene layer / regrind layer /
A four-layer, six-layer fuel container composed of a laminate of an adhesive resin layer / M-EVOH layer / adhesive resin layer / high-density polyethylene layer [inside] (tank with a capacity of about 40 liters: long diameter of 750 m)
m, a short diameter of 530 mm, and a height of 280 mm.

At the start of the production of the fuel container, a laminated body of three types and five layers without a regrind layer, ie, [outside] high-density polyethylene layer / adhesive resin layer / M-EVOH layer /
Performed with the adhesive resin layer / high-density polyethylene layer [inside] (the composition thickness ratio is 60/3/4/3/30). When such burrs and scraps of the laminate (fuel container) are sufficiently generated, The pulverized material obtained by pulverizing burrs and scraps with a pulverizer (diameter 8 mmφ mesh) is directly supplied to an extruder for a regrind layer, and then the above [outside] high-density polyethylene layer / regrind layer / adhesiveness Resin layer / ME
A VOH layer / adhesive resin layer / high-density polyethylene layer [inside] laminate (4 types and 6 layers of fuel container) was prepared, and the generated burrs and scraps were similarly ground and similarly laminated (4 layers).
A pulverized product (apparent density 0.39 g / cc) obtained by repeating the operation of obtaining a fuel container having six seed layers) twice was supplied directly to the extruder for the regrind layer of the fuel container finally obtained.

The thickness of the laminate at the center of the obtained fuel container was 5 mm, and the outer layer was a high-density polyethylene layer / regrind layer / adhesive resin layer / M-EVOH layer / adhesive resin layer / high-density polyethylene. The composition thickness ratio of the layer [inside] is 15
/ 45/3/4/3/30 (the position of the M-EVOH layer is about 33 to 37% from the inside to the outside in the thickness direction).

The fuel container was cut in a direction perpendicular to the major axis and the minor axis, and the regrind layer on the cross section was observed with an optical microscope, and the melt formability was evaluated as follows. ○ −−− The thickness of the regrind layer was uniform, and no waving phenomenon or giant particles due to poor dispersion of EVOH were not observed at all. △ −−− The thickness of the regrind layer was slightly nonuniform and partly wavy. And large particles due to poor dispersion of EVOH were observed. X --- The thickness of the regrind layer was not uniform, and many large particles due to waving phenomenon and poor dispersion of EVOH were observed.

The obtained fuel container was filled with 30 liters of model gasoline (mixing volume ratio = 40/40/10) consisting of a mixed solvent of toluene, isooctane and ethyl alcohol, and the inlet was closed with a metal plate. , The container is 40
One day in an environmental test room set at ± 2 ° C, then -10 ±
After performing an operation of standing for one day in an environmental test room set at 2 ° C., the fuel container is filled with 30 liters of a 50% ethylene glycol aqueous solution, and the concrete surface is raised from a height of 10 m at a temperature of −40 ° C. Was dropped freely, and the mechanical properties (impact resistance) were evaluated as follows. ○ −−− No destruction of the fuel container and no cracks in the regrind layer were observed. △ −−− No destruction of the fuel container was observed, but some cracks in the regrind layer were observed. --- Destruction of the fuel container was partially observed, and many cracks in the regrind layer were observed.

Example 2 In Example 1, 100 parts of the porous precipitate was added in an amount of 0.12%
Into 200 parts of an aqueous calcium acetate solution at 30 ° C.
In the same manner as above, except that water-containing EVOH containing 990 ppm of calcium acetate was obtained.
% Of M-EVOH [containing 250 ppm of calcium], and the same evaluation was performed except that the composition thickness ratio of the fuel container was changed as follows. The thickness of the laminate at the center of the obtained fuel container was 5 mm, [outside] high-density polyethylene layer / regrind layer / adhesive resin layer / M-EVOH layer /
The composition thickness ratio of the adhesive resin layer / high-density polyethylene layer [inside] is 10/45 / 3.5 / 3 / 3.5 / 35 (ME
The position of the VOH layer is about 3 from inside to outside in the thickness direction.
8.5-41.5%).

Example 3 In Example 1, 100 parts of the porous precipitate was added in an amount of 0.09%
Was added to 200 parts of a mixed aqueous solution of magnesium acetate and 0.04% calcium acetate, and stirred at 30 ° C. for 5 hours to obtain a hydrous EVOH containing 710 ppm of magnesium acetate and 320 ppm of calcium acetate in the same manner. M-EVOH having a water content of 0.25% [containing 120 ppm of magnesium and 80 ppm of calcium] was obtained and similarly evaluated.

Example 4 In Example 1, water / methanol (water / water) containing EVOH [ethylene content 26 mol%, saponification degree 99.7 mol%, MFR 3.5 g / 10 min (210 ° C., load 2160 g)] was used. Methanol = 60/40 mixture weight ratio) solution (60 ° C,
M-EVOH having a water content of 0.25% [magnesium was 180p
pm] was obtained, and the same evaluation was performed except that the number of repetitions of the formation of the laminated body until the finally used burrs and scraps were obtained and the number of times of crushing the burrs and scraps were changed to four.

Example 5 In Example 4, 100 parts of the porous precipitate was added in an amount of 0.12%.
Into 200 parts of an aqueous calcium acetate solution at 30 ° C.
In the same manner as above, except that water-containing EVOH containing 990 ppm of calcium acetate was obtained.
% Of M-EVOH [containing 250 ppm of calcium] was evaluated in the same manner.

Example 6 In Example 4, 100 parts of the porous precipitate was added in an amount of 0.09%.
Was added to 200 parts of a mixed aqueous solution of magnesium acetate and 0.04% calcium acetate, and stirred at 30 ° C. for 5 hours to obtain a hydrous EVOH containing 710 ppm of magnesium acetate and 320 ppm of calcium acetate in the same manner. M-EVOH having a water content of 0.25% [containing 120 ppm of magnesium and 80 ppm of calcium] was obtained and similarly evaluated.

Example 7 EVOH [ethylene content 23 mol%, saponification degree 99.
6 mol%, MFR 2.7 g / 10 min (210 ° C., load 2
160 g)] and 100 parts of zinc stearate and 0.12 part of zinc stearate, and a 30 mmφ co-axial twin screw extruder (L / D = 28,
Melt kneading was performed at a temperature of 230 ° C. with a vent) to obtain M-EVOH (containing 124 ppm of zinc) having a water content of 0.15%, and evaluation was performed in the same manner as in Example 1.

Example 8 EVOH [ethylene content 23 mol%, saponification degree 99.
6 mol%, MFR 2.7 g / 10 min (210 ° C., load 2
160 g)] and 100 parts of magnesium stearate 0.1 g.
06 parts and zinc stearate 0.1 part,
mmφ co-rotating twin screw extruder (L / D = 28, with vent)
At 230 ° C. with a water content of 0.15
% Of M-EVOH [containing 24 ppm of magnesium and 103 ppm of zinc] was obtained and evaluated in the same manner as in Example 2.

Example 9 EVOH [Ethylene content 26 mol%, saponification degree 99.
7 mol%, MFR 3.5 g / 10 min (210 ° C., load 2
160g), magnesium acetate is 8 as magnesium
0 parts] and 100 parts of zinc stearate, and a 30 mmφ co-rotating twin screw extruder (L / D = 2
8, with a vent) at 230 ° C. to obtain M-EVOH (containing 80 ppm of magnesium and 40 ppm of zinc) having a water content of 0.15%, and further, changing the grinding conditions of burrs and scraps ( Pulverized material obtained with a diameter of 7 mmφ mesh (apparent density 0.41 g /
Evaluation was performed in the same manner as in Example 1 except that cc) was used. However, magnesium acetate in EVOH was blended by bringing a water-containing porous precipitate of EVOH into contact with a mixed aqueous solution of magnesium acetate, containing magnesium acetate, and then drying.

Example 10 EVOH [Ethylene content 26 mol%, saponification degree 99.
7 mol%, MFR 3.5 g / 10 min (210 ° C., load 2
160 g), and 4 parts of magnesium acetate as magnesium.
0 ppm and 35% of calcium acetate as calcium
100 parts) and 0.05 parts of zinc stearate, and a 30 mmφ co-rotating twin screw extruder (L / D = 28,
Melting and kneading at a temperature of 230 ° C. with a vent (with vent), M-EVOH with a water content of 0.15% [magnesium 40p
pm, 35 ppm calcium and 52 ppm zinc
Was evaluated in the same manner as in Example 1 except that the composition thickness ratio of the fuel container was changed as follows. The thickness of the laminate at the center of the obtained fuel container was 5 mm, [outside].
The composition thickness ratio of the high-density polyethylene layer / regrind layer / adhesive resin layer / M-EVOH layer / adhesive resin layer / high-density polyethylene layer [inside] is 10/50/5/5/5/2.
5 (the position of the M-EVOH layer was about 30 to 35% from the inside to the outside in the thickness direction). However, regarding magnesium acetate and calcium acetate in EVOH,
The water-containing porous precipitate of EVOH was contacted with a mixed aqueous solution of magnesium acetate and calcium acetate to contain magnesium acetate and calcium acetate, and then dried to mix.

Comparative Example 1 In Example 1, 100 parts of the porous precipitates were
% Magnesium acetate aqueous solution at 30 ° C.
For 5 hours to obtain a water-containing EVOH containing 30 ppm of magnesium acetate in the same manner as described above.
25% EVOH [containing 5 ppm of magnesium] was obtained and evaluated similarly.

Comparative Example 2 In Example 1, 100 parts of the porous precipitate were put into 200 parts of a 0.4% aqueous magnesium acetate solution, and the mixture was heated at 30 ° C. for 5 hours.
In the same manner as described above, except that water-containing EVOH containing 3200 ppm of magnesium acetate was obtained by stirring for 0.5 hour.
25% EVOH [containing 540 ppm of magnesium]
And evaluated similarly. Table 1 summarizes the evaluation results of the examples and comparative examples.

[Table 1] Melt formability Mechanical properties (impact resistance) Example 1 ○ ○ 〃 2 ○ ○ 〃 3 ○ ○ ４ 4 ○ ○ ５ 5 ○ ○ ６ 6 ○ ○ 〃 7 ○ ○ ８ 8 ○ ○ ９ 9 ○ ○ 〃 10 ○ ○ Comparative Example 1 × × 〃 2 × ×

[0064]

According to the method for manufacturing a fuel container of the present invention, since a regrind layer is formed by using a pulverized product of a laminate of an intermediate layer composed of a specific EVOH and an outermost layer composed of a thermoplastic resin, the melt molding is performed. It is excellent in performance, mechanical properties, and economy, and it is used for fuel tanks such as automobile gasoline fuel tanks, motorcycles, ships, aircraft, generators, and industrial and agricultural equipment. It is useful as a method for manufacturing a portable container for replenishment, and various fuel containers such as bottles, tanks, and drums for transporting, storing, and storing these fuels.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 10, 2001 (2001.4.1
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

In the present invention, the above-mentioned various additives, modifiers, other resins and the like may be added to the pulverized product of the laminate as long as the object of the present invention is not impaired. In particular, saturated aliphatic amides (eg, stearic acid amide, etc.), unsaturated fatty acid amides (eg, oleic acid amide, etc.), bisfatty acid amides (eg, ethylene bisstearic acid amide, etc.), low molecular weight polyolefins (eg, molecular weight 500 to 10,000) Low molecular weight polyethylene,
Or low-molecular-weight polypropylene, etc.), inorganic salts (for example, Kyowa Chemical Co., Ltd. hydrotalcite compound "DH
T-4A "and the hydrotalcite solid solution " ZHT-4 "
A "), an antioxidant (for example, a hindered phenolic“ Irganox 1 ”manufactured by Ciba Specialty Chemicals)
010 "and" Irganox 1098 ") and the like, and the compounding amount thereof is 0.001 to 1 part by weight (further 0.01 to 0.5 part by weight) based on 100 parts by weight of the pulverized product of the laminate.
Parts by weight).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 65/40 BRJ C08L 29/04 S C08K 5/098 BSN B65D 1/00 B C08L 29/04 B60K 15 / 02 A F term (reference) 3D038 CC20 3E033 BA30 BB08 CA20 FA02 FA03 GA02 3E086 AD04 AD30 BA04 BA15 CA40 4F100 AH02A AK01 AK01B AK01C AK05 AK69A BA03 BA05 BA10B BA10C BA15 BA25 CB00 J01 EB05B12 E112 EB05B01 YY00A 4J002 BB221 BE031 DE236 DE246 DG046 DG056 DH046 DK006 EG036 EG046 EG056 GG01

Claims (8)

[Claims] 1. A composition containing at least one selected from magnesium, calcium, and zinc, wherein the total content is 1
Production of a fuel container, wherein a pulverized product of a laminate in which a saponified ethylene-vinyl acetate copolymer of 0 to 500 ppm is used as an intermediate layer and a thermoplastic resin is laminated on at least both outermost layers is used as a regrind layer. Method. 2. The method according to claim 1, wherein at least one selected from magnesium, calcium, and zinc is contained as an acetate. 3. The method for producing a fuel container according to claim 1, wherein at least one selected from magnesium, calcium, and zinc is contained as a stearate and / or a hydroxystearate. 4. The pulverized product of the laminate has an apparent density of 0.25.
2. The composition according to claim 1, wherein the weight is 0.55 g / cc.
3. The method for manufacturing a fuel container according to any one of 3). 5. The pulverized product of the laminate is directly supplied to an extruder for a regrind layer of a molding machine.
5. The method for producing a fuel container according to any one of claims 4 to 4. 6. The laminated structure of the fuel container is at least thermoplastic resin layer / regrind layer / adhesive resin layer / saponified ethylene-vinyl acetate copolymer layer / adhesive resin layer / thermoplastic resin layer. The method for producing a fuel container according to any one of claims 1 to 5, wherein 7. The fuel container according to claim 1, wherein the saponified layer of the ethylene-vinyl acetate copolymer is at a position of 20 to 60% from the inside to the outside in the thickness direction of the fuel container.
7. The method for producing a fuel container according to any one of claims 6 to 6. 8. The method according to claim 1, wherein the fuel container is an automobile fuel tank.