JP2002361657A - Rotary molding container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary molding container excellent in falling impact resistance, interlaminar bonding or the like. SOLUTION: A outer layer comprises a thermoplastic resin and an inner layer comprises a composition containing a saponified ethylene/vinyl acetate copolymer and a polyamide resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotationally molded container using a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH).

[0002]

2. Description of the Related Art In general, EVOH is excellent in gas barrier properties, transparency, fragrance retention, solvent resistance, oil resistance, and the like.
It is used for various packaging materials such as industrial chemical packaging materials and agricultural chemical packaging materials. Then, it has been proposed to manufacture a rotomolded container using such EVOH and a polyolefin-based resin.

For example, JP-A-3-2009 discloses that
A rotary molding container is described in which a polyolefin is used for an outer layer, EVOH is used for an inner layer, and irregularities are formed at an interface of the EVOH layer. In addition, a rotomolded container is a two-part closed mold, which is charged with plastisol or powdered resin equivalent to the product weight and heated in a melting furnace while simultaneously rotating anisotropically (rotating and revolving) to form a plastisol or powder. The resin is heated and melted while uniformly adhering to the inner wall of the mold to obtain a hollow molded container.

[0004]

However, in the method disclosed in the above-mentioned publication, since the unevenness is formed at the interface of the EVOH layer, the improvement of the adhesiveness at the interface can be expected, but the transparency of the container is not improved. Is expected to decrease, and EVOH
EVO when stress concentrates on the concave part of the layer (during drop impact etc.)
There is a possibility that the H layer may be cracked or delamination may occur, and improvement is desired.

[0005]

Accordingly, the present inventors have conducted intensive studies in view of the present situation, and as a result, have found that the outer layer contains a thermoplastic resin and the inner layer contains EVOH (A) and a polyamide resin (B). The present invention has been completed, which has been found that a rotomolded container made of a composition which can solve the above problems.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The most significant feature of the rotary molded container of the present invention is that a composition containing EVOH (A) and a polyamide resin (B) in the inner layer is used. EVOH (A) contained in such a composition is not particularly limited,
When the ethylene content is 10 to 70 mol% (further 20 to 60 mol%)
Mol%, especially 25 to 50 mol%), and a saponification degree of 90 mol% or more (more preferably 95 mol% or more, particularly 99 mol% or more) is used, and the ethylene content is 10 mol%.
If less, the gas barrier property at high humidity and the melt moldability are reduced,
Conversely, if it exceeds 70 mol%, sufficient gas barrier properties cannot be obtained, and if the degree of saponification is less than 90 mol%, gas barrier properties cannot be obtained.
Thermal stability, moisture resistance, etc. are undesirably reduced.

The melt flow rate (MFR) of EVOH (A) (210 ° C., load 2160 g) is 0.5
-100 g / 10 min (more preferably 1-50 g / 10 min, particularly 3-35 g / 10 min). When the MFR is smaller than the above range, the fluidity is insufficient and the film formation is uneven. When it is larger than the above range, the thickness accuracy of the obtained hollow container is undesirably reduced.

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

In the present invention, a copolymerizable ethylenically unsaturated monomer may be copolymerized as long as the effects of the present invention are not impaired. Examples of such a monomer include propylene and 1-butene. , Olefins such as isobutene, acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid,
Unsaturated acids such as (anhydride) maleic acid and (anhydride) itaconic acid or salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, 1 to 1 carbon atoms
8, acrylamides such as N-alkylacrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, methacrylamide, having 1 to 18 carbon atoms Methacrylamides such as N-alkylmethacrylamide, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, N-vinylpyrrolidone N-vinylamides such as, N-vinylformamide and N-vinylacetamide;
Vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and vinyl bromide And vinylsilanes such as trimethoxyvinylsilane, allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl)-
Examples thereof include ammonium chloride and acrylamide-2-methylpropanesulfonic acid. Further, post-modification such as urethanization, acetalization, and cyanoethylation may be performed as long as the gist of the present invention is not impaired.

It is also possible to use two or more different EVOHs as the EVOH (A). In this case, the ethylene content differs by 5 mol% or more and / or the saponification degree differs by 1 mol% or more. Use of a blend of EVOH having a ratio of MFR of 4 or more is useful because the flexibility of the formed film and the stability of film formation are further improved while maintaining gas barrier properties.

The polyamide resin (B) contained in the composition is, specifically, polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9). ), Polyundecaneamide (nylon 11), polylauryl lactam (nylon 12), polyethylene diamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 6)
6), polyhexamethylene sebacamide (nylon 61
0), polyhexamethylene dodecamide (nylon 61
2), polyoctamethylene adipamide (nylon 8,
6), polydecamethylene adipamide (nylon 10
8), caprolactam / lauryl lactam copolymer (nylon 6/12), caprolactam / ω-aminononanoic acid copolymer (nylon 6/9), caprolactam / hexamethylene diammonium adipate copolymer (nylon 6/66), Lauryl lactam / hexamethylene diammonium adipate copolymer (nylon 12/6
6), ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (nylon 26/6
6), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 66/610), ethylene ammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 6 / 66/610), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, hexamethylene isophthalamide / terephthalamide copolymer or a polyamide resin modified with an aromatic amine such as methylenebenzylamine or meta-xylenediamine And meta-xylylenediammonium adipate.

Among such polyamide resins (B),
In order to obtain the effects of the present invention more remarkably, the melting point must be 1
It is preferable to use one having a temperature of 60 ° C. or lower,
It is 0-150 degreeC, especially 80-140 degreeC.

Here, the melting point is defined as a differential scanning calorimeter (DS).
C) represents a melting peak temperature (° C.) measured at a rate of temperature increase of 10 ° C./min.

The method for adjusting the melting point of the polyamide resin (B) is not particularly limited. Industrially, it is preferable to use a copolymer having a specific ratio among the above polyamide resins. It is not limited to this.

Examples of the polyamide resin (B) having a melting point of 160 ° C. or less include nylon 6/12, nylon 6/69, nylon 6/66/610, and nylon 6
/ 66/610/12, nylon 6/66/610/1
1 and its aromatic amine modified products, and specific commercially available trade names are “Amilan CM400
0 ”,“ Amilan CM8000 ”,“ Amilan CM65 ”
41-X3 "," Amilan CM831 "," Amilan C
M833 ”(all manufactured by Toray Industries, Inc.),“ Elvamide 806 ”
1 ”,“ Elvamide 8062S ”,“ Elvamide 806 ”
6 (above, manufactured by DuPont Japan), "Grillon CF
6S ”,“ Grillon CF62BS ”,“ Grillon CA6 ”
E "," Grillon XE3381 "," Grillon BM13
SBG ”(above, manufactured by MMS Japan),“ UBE71 ”
28B "and" UBE7028B "(all manufactured by Ube Industries, Ltd.).

The polyamide resin (B) having a melting point of more than 160 ° C. includes “Amilan CM6541-X”.
4, Amilan CM1017, Amilan CM30
01-N "," Amiran CM1021FS "," Amiran CM1046 "," Amiran U121 "(all manufactured by Toray Industries, Inc.)," Grillon A23G "," Grillon T300G "
M "," Grillon CR9 "," Grillon PV-15 "
H "," Grillon XE3222 "(above, manufactured by MMS Japan)," UBE1011FB "," UBE2015 "
B "(above, manufactured by Ube Industries)," Novamid 1010C
2, Novamid 3010N, Novamid X2
1 "(above, manufactured by Mitsubishi Engineering-Plastics Corporation).

Further, the polyamide resin (B) was measured using a differential scanning calorimeter (DSC) (heating rate 10 ° C./mi).
n) The amount of heat of fusion ΔH is 80 J / g or less (and 5
To 70 J / g, particularly preferably 10 to 60 J / g),
If the heat of fusion ΔH exceeds 80 J / g, the effects of the present invention may be undesirably reduced.

The heat of fusion (ΔH) of the polyamide resin is 8
The method for reducing the concentration to 0 J / g or less is not particularly limited.
Industrially, it can be suitably carried out by controlling the degree of polymerization, the molecular weight, the molecular weight distribution, the content of low molecular weight components, the amount of water, the amount of residual monomers and the like in the polyamide resin.

Further, the melt flow rate (MFR) of the polyamide resin (B) (210 ° C., load 2160 g)
Is 1 to 100 g / 10 min (further 3 to 80 g / 10 min.
(Particularly, 5 to 50 g / 10 minutes). When the melt flow rate is out of the range, the effect of the present invention may be reduced, which is not preferable.

The method for controlling the MFR of the polyamide resin within the above range is not particularly limited. However, industrially, the degree of polymerization, molecular weight, molecular weight distribution, low molecular weight component content, moisture content, residual monomer It can be suitably performed by controlling the amount and the like.

In the present invention, the polyamide resin (B) includes a structure, a composition, a melting point, a heat of fusion, and a molecular weight (MF).
R), two or more kinds of polyamide resins having different molecular weight distributions can be used in combination.

The composition used for the inner layer of the rotomolded container of the present invention contains (A) and (B) as described above, and the content ratio is not particularly limited. / B) is 50/50 to 99/1 (further 60/50).
When the weight ratio is less than 50/50, the gas barrier property may be insufficient, and conversely, when the weight ratio is greater than 99/1. In some cases, the effects of the present invention may not be sufficiently obtained, which is not preferable.

The above composition may contain boron or a boron compound (C) in addition to the above (A) and (B), since the effect of the present invention can be sufficiently obtained. preferable.

Examples of the boron compound (C) include boric acid, calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), aluminum / potassium borate, ammonium borate (metaborate) Ammonium, ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc.), cadmium borate (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate (potassium metaborate, potassium tetraborate,
Potassium pentaborate, potassium hexaborate, potassium octaborate, etc., silver borate (silver metaborate, silver tetraborate, etc.), copper borate (cupric borate, copper metaborate, copper tetraborate) Sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.),
Lead borate (lead metaborate, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, metaborate) Barium, barium diborate, barium tetraborate, etc.), bismuth borate,
Magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.), manganese borate (manganese borate 1, manganese metaborate,
In addition to manganese tetraborate and the like, lithium borate (lithium metaborate, lithium tetraborate, lithium pentaborate and the like), and boric acid such as borax, carnite, inyoite, goethite, sianite, and Zeyberite Salt minerals and the like, preferably borax, boric acid, sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.) Is used.

The content of (C) is not particularly limited, but is 1% in terms of boron with respect to the total amount of (A) and (B).
0-10000 ppm (further 20-5000 ppm,
In particular, the content of (C) is preferably less than 10 ppm. If the content is less than 10 ppm, the effect of containing (C) may not be sufficiently exerted. Is not preferable because it tends to deteriorate.

In order to prepare such a composition, a resin composition containing the above (A) and (B) or (A) to (C) may be prepared. Without limitation, (A) and (B) or (A) ~
The component (C) may be blended, and in the former blend of (A) and (B), generally both may be melt-kneaded, and in the latter blend of components (A) to (C), Specifically, a method in which the components (A) to (C) are mixed at once and then melt-kneaded, and the components (A) and (B)
A method of melt-kneading the components and then adding the component (C) and further melt-kneading, a method of adding the component (C) to the component (A) and then melt-kneading the component (B), A method of melt-kneading the component (A) after the component (C) is contained; a method of melt-kneading the components (A) and (B) after the component (C) is contained in each of the components;
A method of uniformly dissolving the component (C) in a solvent capable of dissolving and mixing and then removing the solvent can be mentioned. A preferred method is used, and such a method is described in more detail. However, the present invention is not limited to this.

When the boron or boron compound (C) is contained in the EVOH (A), the EVOH (A) can be contained by bringing the aqueous solution of the boron or boron compound (C) into contact with the EVOH (A). The concentration of boron or the boron compound (C) in the aqueous solution is 0.001 to 1% by weight (further, 0.005 to 0.8% by weight, particularly 0.01 to 0.5% by weight) in terms of boron. Preferably
If the amount is less than 0.001% by weight, it becomes difficult to contain a predetermined amount of boric acid. Conversely, if the amount exceeds 1% by weight, the appearance of the obtained rotomolded container may be unfavorably deteriorated.

The method of bringing EVOH (A) into contact with the aqueous solution is not particularly limited, but usually, the above-mentioned boron or boron compound is charged with the EVOH (A) formed into pellets into the aqueous solution and stirred. It is preferable to contain (C).

In preparing (molding) the above-mentioned EVOH pellets, a known method can be adopted.
For example, after a mixed solution of EVOH (A) in water and alcohol is extruded into a coagulating liquid into a strand or a sheet, the resulting strand or sheet may be cut into pellets. As the shape of the EVOH (A) in the form of a pellet, a columnar shape, a spherical shape or the like is preferable. In the case of a cylindrical shape, the diameter is preferably 1 to 10 mm and the length is 1 to 10 mm. 10 to 10 mm is preferred. The EVOH (A) has a diameter of 0.1 to 10
Those having a microporous internal structure in which pores of about μm are uniformly distributed are preferable in that they can uniformly contain boron or boron compound (C), and usually EVOH (A)
When extruding a solution (water / alcohol mixed solvent or the like) into a coagulation bath, the concentration of the EVOH (A) solution (20 to 80% by weight), the extrusion temperature (45 to 70 ° C), and the type of solvent (water / alcohol) Mixing weight ratio = 80 / 20-5 / 95
Etc.), the temperature of the coagulation bath (1 to 20 ° C.), the residence time (0.2
5 to 30 hours), the amount of EVOH (A) in the coagulation bath (0.
(2 to 2% by weight), etc., it is possible to obtain EVOH (A) having the structure. Further, those having a water content of 20 to 80% by weight are preferable because the compounds and the like can be uniformly and rapidly contained. In adjusting the content of boron or boron compound (C), although not particularly limited, in the above-mentioned contact treatment with an aqueous solution, the concentration of the aqueous solution of boron or boron compound (C), the contact treatment time, the contact treatment temperature, This can be achieved by controlling the stirring speed during the contact treatment, the water content of the EVOH (A) to be treated, and the like.

Thus, boron or a boron compound (C)
Is obtained in the form of pellets, and usually, the composition is obtained through a drying step after the above-mentioned contact treatment.

As such a drying method, various drying methods can be adopted. For example, fluid drying is performed while the composition in the form of pellets or the like is stirred or dispersed by mechanical or hot air, and the composition in the form of pellets or the like is given a dynamic action such as stirring or dispersion. Drying is carried out without drying. Examples of the 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 cone. Rotary dryers and the like, and as a dryer for performing stationary drying, a batch type box dryer as a material stationary type,
Examples of the material transfer type include, but are not limited to, a band dryer, a tunnel dryer, and a vertical dryer. 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 deterioration of the composition. The time for the drying treatment depends on the water content of the composition and the amount of the treatment, but usually about 15 minutes to 72 hours is preferable in terms of productivity and prevention of thermal deterioration of the composition.

The composition is dried under the above conditions,
An EVOH composition comprising VOH (A) and boron or a boron compound (C) is obtained. The moisture content of the composition after the drying treatment is 0.001 to 5% by weight (further, 0.01 to 5% by weight). 2% by weight, especially 0.1 to 1 part by weight), and the water content is 0.001% by weight.
If the amount is less than 5, gel tends to be generated at the time of melt-kneading with the polyamide resin (B) described later, and if the amount exceeds 5% by weight, foaming tends to occur at the time of melt-kneading with the polyamide resin (B) described later. It is not preferable.

Next, the polyamide resin (B) is further melted in the EVOH composition [pellet of (A) containing (C)] comprising the obtained EVOH (A) and boron or boron compound (C). The kneading is not particularly limited, and the melt kneading is not particularly limited as long as the EVOH composition and the polyamide resin (B) are sufficiently kneaded, and a known method can be employed. For example, a known kneading apparatus such as a kneader ruder, an extruder, a mixing roll, a Banbury mixer, a plast mill, or the like can be used.
(280 ° C.) for about 1 minute to 1 hour. It is preferable to use an extruder such as a single-screw extruder or a twin-screw extruder industrially. It is also preferable to provide a suction device, a gear pump device, a screen device, and the like. In particular, in order to remove moisture and by-products (such as pyrolyzed low-molecular-weight products), the extruder is provided with one or more vent holes to suck under reduced pressure or to prevent oxygen from being mixed into the extruder. By continuously supplying an inert gas such as nitrogen into the hopper, it is possible to obtain a high-quality composition with reduced thermal coloring and thermal deterioration. In the melt kneading, 1) a method in which the solid EVOH composition and the polyamide resin (B) are mixed and kneaded at once.
2) A method in which a solid polyamide-based resin (B) is charged into a molten EVOH composition and melt-kneaded. 3) A solid EVOH composition is charged into a molten polyamide resin (B) and melted. A method of mixing and 4) a method of mixing the EVOH composition in a molten state and the polyamide resin (B) and melt-kneading the mixture.

Thus, the composition used for the inner layer of the molding container of the present invention can be obtained. The composition further contains acids such as acetic acid and phosphoric acid and their alkali metals, alkaline earth metals and transition metals. It is also preferable to include a metal salt such as the above, in that the thermal stability of the resin composition, the interlayer adhesion with a thermoplastic resin and the like are improved, and particularly, alkali metal salts and alkaline earth metal salts are excellent in their effects. Is preferably used.

Examples of such metal salts include acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, such as sodium, potassium, calcium, and magnesium.
Metal salts of organic acids such as behenic acid and the like, and inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid and the like can be mentioned, and preferred are acetate, phosphate and hydrogen phosphate. The content of the metal salt is 5 to 1000 ppm in terms of metal with respect to the composition.
(Furthermore, 10 to 500 ppm, especially 20 to 300 pp
m) is preferable. If the content is less than 5 ppm, the content effect may not be sufficiently obtained. Conversely, if the content is more than 1000 ppm, thermal decomposition of the composition is promoted, and odor, foaming, and coloring increase. It is not preferable because it may occur. When two or more kinds of alkali metal and / or alkaline earth metal salts are contained in the composition, the total amount is preferably within the above range.

The method for incorporating the acids and their metal salts into the composition is not particularly limited, and the EVOH (A)
Or EVOH composition.
(A) Or EVOH composition and polyamide resin (B)
At the same time as blending, or in the EVOH (A) or the composition after blending the EVOH composition with the polyamide resin (B), or a combination of these methods. In order to obtain the effect of the present invention more remarkably, a method of previously containing EVOH (A) or an EVOH composition is preferable in terms of excellent dispersibility of acids and metal salts thereof.

As a method of preliminarily containing EVOH (A), there are a) EVOH having a water content of 20 to 80% by weight.
A method in which the porous precipitate of (A) is brought into contact with an aqueous solution of an acid or a metal salt thereof to contain the acid or a metal salt thereof, and then dried, and a) a uniform EVOH solution (water / alcohol solution or the like). After containing acids and their metal salts, extruding them into a coagulating solution in the form of a strand, and then cutting the resulting strand into pellets for further drying treatment, c)
A method in which EVOH (A) and acids and their metal salts are mixed at once and then melt-kneaded by an extruder or the like; d) EVOH (A)
In the production of, the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step is neutralized with an acid, such as acetic acid, and the remaining acids, such as acetic acid, and by-produced sodium acetate, potassium acetate, etc. A method of adjusting the amount of the alkali metal salt by a water washing treatment, and the like can be given.
In order to obtain the effect of the present invention more remarkably, the method a), a) or d), which is excellent in dispersibility of acids and metal salts thereof, is preferable. In addition, in order to be contained in the EVOH composition,
What is necessary is just to make it contain simultaneously with (C) in EVOH (A).

In the present invention, a saturated aliphatic amide (eg, stearic acid amide), an unsaturated fatty acid amide (eg, oleic acid amide, etc.), a bisfatty acid, etc. may be added to such a composition as long as the object of the present invention is not impaired. Amides (e.g., ethylene bisstearic acid amide, etc.), fatty acid metal salts (e.g., calcium stearate, magnesium stearate, zinc stearate, etc.), low molecular weight polyolefins (e.g., low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or low molecular weight polypropylene) ), An inorganic salt (for example, hydrotalcite, etc.), a plasticizer (for example, aliphatic polyhydric alcohol such as ethylene glycol, glycerin, hexanediol, etc.), an oxygen absorbent (for example, reducing as an inorganic oxygen absorbent, Iron powders, as well as water-absorbing substances and electrolytes Additives, aluminum powder, potassium sulfite, photocatalytic titanium oxide, etc. are used as organic compound-based oxygen absorbers, such as ascorbic acid, fatty acid esters and metal salts thereof, and polyvalents such as hydroquinone, gallic acid, and hydroxyl-containing phenol aldehyde resins. Coordination conjugates of nitrogen-containing compounds such as phenols, bis-salicylaldehyde-imine cobalt, tetraethylene pentamine cobalt, cobalt-Schiff base complexes, porphyrins, macrocyclic polyamine complexes, polyethylene imine-cobalt complexes and transition metals , Terpene compounds, reactants of amino acids and hydroxyl group-containing reducing substances, triphenylmethyl compounds, etc., as high molecular oxygen absorbers,
Coordination conjugate of nitrogen-containing resin and transition metal (eg, combination of MXD nylon and cobalt), blend of tertiary hydrogen-containing resin and transition metal (eg, combination of polypropylene and cobalt), carbon-carbon unsaturated A blend of a bond-containing resin and a transition metal (eg, a combination of polybutadiene and cobalt), a photo-oxidatively degradable resin (eg, a polyketone), an anthraquinone polymer (eg, polyvinyl anthraquinone),
Further, a photoinitiator (such as benzophenone), a peroxide supplement (such as a commercially available antioxidant) or a deodorant (such as activated carbon) is added to these compounds, etc.), a heat stabilizer, a light stabilizer, Antioxidants, ultraviolet absorbers, coloring agents, antistatic agents, surfactants, antibacterial agents, antiblocking agents (such as talc fine particles), slip agents (such as amorphous silica), fillers (such as inorganic fillers) Alternatively, other resins (for example, polyolefin, polyester, etc.) may be blended.

On the other hand, the thermoplastic resin used for the outer layer of the rotomolding container of the present invention is not particularly limited, and specific examples thereof include linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and medium-density polyethylene. Polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene (block or random) copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer Polymers, ethylene-methacrylic acid ester copolymers, polypropylene, propylene-α-olefin (C 4-20 α-olefin) copolymers, homo- or copolymers of olefins such as polybutene, polypentene and polymethylpentene Or the homo- or copolymers of these olefins Polyolefin resins, polyester resins, polyamide resins (including copolymerized polyamides), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl, etc. in a broad sense, such as those graft-modified with rubonic acid or esters thereof Ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, aromatic or aliphatic polyketones, polyalcohols obtained by reducing these, and EVOH, etc. In terms of practicality such as mechanical strength, a polyolefin-based resin is preferable, and high-density polyethylene and medium-density polyethylene are particularly preferably used.

The rotomolded container of the present invention is manufactured using the thermoplastic resin and the composition as described above, and the manufacturing method can be a known method, and is not particularly limited. .

For example, a thermoplastic resin required to form a desired thickness in a mold having a desired hollow container shape is charged, and the mold is heated (depending on the type of thermoplastic resin. , About 200 to 300 ° C.), and the outer layer of the thermoplastic resin is formed while rotating the mold. Then, a predetermined amount of the composition is charged into a mold, and an inner layer of the composition is similarly formed, whereby the rotomolding container of the present invention can be obtained. In addition, the temperature at the time of heating of a composition is 200-300.
It is preferably set to ° C.

In the present invention, it is also possible to use an adhesive resin between the inner layer and the outer layer for the purpose of further improving the interlayer adhesive force, and various adhesive resins are used. Although it cannot be said unconditionally depending on the type of the thermoplastic resin, the unsaturated carboxylic acid or its anhydride can be chemically added to an olefin-based polymer (the above-mentioned olefin alone or copolymer) by an addition reaction, a graft reaction or the like. Modified olefin polymer containing a carboxyl group obtained by chemically bonding, 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, maleic anhydride graft-modified ethylene anhydride - one or a mixture of two or more species selected from vinyl acetate copolymers and the like as preferred. At this time, the content of the unsaturated carboxylic acid or its anhydride is preferably 0.001 to 3% by weight, more preferably 0.01 to 1% by weight, and particularly preferably 0.03 to 0.5% by weight. It is. If the content is small, the adhesiveness may be insufficient, and if it is too large, a crosslinking reaction may occur, which may result in poor moldability.

Further, these adhesive resins are blended with other thermoplastic resins, rubber / elastomer components such as EVOH, polyisobutylene, and ethylene-propylene rubber, as well as the thermoplastic resin of the outer layer and the composition of the inner layer. It is also possible. In particular, by blending a polyolefin resin different from the base polyolefin resin of the adhesive resin, the adhesiveness may be improved, which is useful.

The thickness of each layer of the obtained rotomolded container cannot be determined unconditionally depending on the kind of outer layer, the use and the form of the container, and the required physical properties.
(Further 1 to 5 mm), the inner layer is selected from the range of 0.1 to 5 mm (further 0.5 to 3 mm), and the adhesive resin layer is selected from the range of about 0.1 to 5 mm (further 0.5 to 3 mm). You. When the inner layer is less than 0.1 mm, the gas barrier properties are insufficient, and the thickness control is unstable. On the other hand, when the inner layer is more than 5 mm, the impact resistance is poor, and it is not economical. Insufficient rigidity, conversely, if it exceeds 15 mm, the weight increases, and it is not economical and not preferable.If the adhesive resin layer is less than 0.1 mm, the interlayer adhesion is insufficient, and the thickness control becomes unstable, Conversely, if it exceeds 5 mm, the weight increases, and it is not economical and is not preferable.

In the present invention, in addition to the layer structure of the outer layer (thermoplastic resin layer) / inner layer (composition layer) or the outer layer (thermoplastic resin layer) / adhesive resin layer / inner layer (composition layer), , Outer layer (thermoplastic resin layer) / composition layer / thermoplastic resin layer / inner layer (composition layer), outer layer (thermoplastic resin layer) / adhesive resin layer / composition layer / adhesive resin layer / inner layer (composition Layer), an outer layer (thermoplastic resin layer) / adhesive resin layer / composition layer / adhesive resin layer / thermoplastic resin layer / adhesive resin layer / inner layer (composition layer), and a regrind layer. Outer layer (thermoplastic resin layer) / regrind layer / adhesive resin layer / inner layer (composition layer), outer layer (thermoplastic resin layer) / regrind layer / adhesive resin layer / composition layer / adhesive resin Layer / inner layer (composition layer), outer layer (thermoplastic resin layer) / regrind layer / adhesive resin layer / set Object layer / adhesive resin layer / thermoplastic resin layer / adhesive resin layer / inner layer (composition layer), and can be.

In the case of three or more layers, it is possible to repeat rotational molding according to the method described above.

The rotomolded container of the present invention thus obtained is excellent in drop impact resistance, interlayer adhesion and the like, and is useful as a container for fuels, organic solvents, various industrial chemicals, etc. tanks, bottles, drums and the like. In particular, it is useful for gasoline tanks of automobiles, containers for transportation, drums for storage and transfer, bottles for chemicals and pesticides, and the like.

[0050]

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

Regarding the measurement of the melting point of the polyamide resin, a differential scanning calorimeter (“DSC-
7 ") at a heating rate of 10 ° C./min. The boric acid content in EVOH was measured by melting EVOH with alkali and quantifying boron by ICP emission spectroscopy. Further, the measurement of the alkali metal content was carried out by dissolving the EVOH in an aqueous solution of hydrochloric acid after incineration and quantifying the alkali metal by atomic absorption spectrometry.

Example 1 EVOH containing 0.2% boric acid (C) [ethylene content: 34 mol%, degree of saponification: 99.5 mol%, MFR: 3 g
/ 10 min (210 ° C., load 2160 g), containing 400 ppm of sodium acetate] (A) 85 parts and polyamide resin [Grillon CF6S manufactured by EMS Japan Co., copolymer of nylon 6/12, density 1.05 g / cm ³ , melting point 133 ° C., ΔH 51 J / g, MFR 18 g / 10 min (2
15 ° C., 10 ° C., load 2160 g)] (B) was melt-kneaded under the following conditions using a twin-screw extruder to obtain a composition [containing 300 ppm of boron and 95 ppm of sodium] used for the inner layer.

Next, a thermoplastic resin (HB215R, HDPE, manufactured by Nippon Polychem Co., Ltd.) for the outer layer was charged into a biaxial rotary molding machine (for producing a cylindrical container having an insert metal opening and having a diameter of 30 cm and a volume of 30 liters). Then 27
After heating to 0 ° C. and rotating to form an outer layer (average thickness 3 mm), the above composition is charged and heated to 270 ° C. and rotating to form an inner layer (average thickness 1.2 mm). Thus, a rotomolded container of the present invention was obtained.

The following evaluation was performed on the obtained rotomolded container. (Drop impact resistance) The obtained molded container is filled with 29 liters of water, the opening is sealed with a screw cap, and the bottom surface of the container is parallel to the concrete surface from a height of 2 m in a -40 ° C atmosphere. Was naturally dropped on a concrete surface so that the condition of the inner layer was visually observed and evaluated as follows.・ ・ ・: No abnormality was observed. ・ ・ ・: Cracks occurred slightly, but there was no problem in practical use. ×: Countless cracks occurred in the composition layer (inner layer).

(Interlayer Adhesion) After the above-described drop impact resistance test was performed, the cross section of the body portion of the rotomolded container was visually observed and evaluated as follows.・ ・ ・: No peeling was observed between the layers ・ ・ ・: Slight peeling was observed in a part of the interlayer, but there was no problem in practical use ×: Almost peeled between the layers

Example 2 EVOH containing 0.13% of boric acid (C) [ethylene content 29 mol%, saponification degree 99.6 mol%, MFR 1
5 g / 10 min (210 ° C., load 2160 g), containing 400 ppm of sodium acetate, containing 90 ppm of potassium acetate] (A) 85 parts and a polyamide resin [“Grillon CF6S” manufactured by EMS Japan Co., a copolymer of nylon 6/12, Density 1.05 g / cm ³ , melting point 133 ° C, ΔH5
1 J / g, MFR 18 g / 10 min (210 ° C., load 21
Example 2 except that 15 parts of (B) was melt-kneaded with a twin-screw extruder under the following conditions to obtain an inner layer composition [containing 195 ppm of boron, 95 ppm of sodium, and 30 ppm of potassium]. Similarly, a rotomolded container was obtained and similarly evaluated.

Example 3 EVOH containing 0.13% of boric acid (C) [ethylene content 38 mol%, saponification degree 99.6 mol%, MFR 3
g / 10 min (210 ° C., load 2160 g), containing 336 ppm of sodium acetate, sodium dihydrogen phosphate 92p
pm, 230 ppm calcium acetate] (A) 8
5 parts and polyamide resin ["Grillon CF6S" manufactured by EMS Japan Co., nylon 6/12 copolymer, density 1.05 g / cm ³ , melting point 133 ° C, ΔH51J / g,
MFR 18 g / 10 min (210 ° C., load 2160 g)]
(B) Rotational molding was performed in the same manner as in Example 1 except that 15 parts were melt-kneaded with a twin-screw extruder under the following conditions to obtain a resin composition [containing 195 ppm of boron, 95 ppm of sodium, and 50 ppm of calcium]. A container was obtained and similarly evaluated.

Example 4 In Example 1, "Amilan CM8000" [nylon 6/66/610/12] manufactured by Toray was used as the component (B).
A density of 1.12 g / cm ³ , a melting point of 131 ° C.
A rotation-molded container was obtained in the same manner except that ΔH40J / g, MFR 25 g / 10 minutes (210 ° C., load 2160 g) was used, and the same evaluation was performed.

Example 5 In Example 1, "Grillon CA6E" (nylon 6/12 copolymer, density 1.06 g / cm ³ , melting point 124 ° C., ΔH 39
J / g, MFR 26g / 10 min (210 ° C, load 216
0g)], except that a rotomolded container was obtained and evaluated in the same manner.

Example 6 In Example 1, "Amiran CM6541-X3" [a copolymer of nylon 6/12, density 1.11 g / cm ³ , melting point 135 ° C., ΔH 40
J / g, MFR 12 g / 10 min (210 ° C., load 216
0g)], except that a rotomolded container was obtained and evaluated in the same manner.

Example 7 In Example 1, "Amilan CM6541-X4" (a copolymer of nylon 6/12, density 1.10 g / cm ³ , melting point 196 ° C.) manufactured by Toray Co., Ltd. was used as the component (B). A rotation molded container was obtained in the same manner except that the container was used, and the evaluation was performed in the same manner.

Example 8 In Example 1, "Amilan CM1017" manufactured by Toray Co., Ltd. [nylon 6, density 1.13 g / c] was used as the component (B).
m ³ , melting point: 225 ° C.], and a rotomolded container was obtained in the same manner and evaluated in the same manner.

Example 9 In Example 1, an adhesive resin having an average thickness of 1 mm between the outer layer and the inner layer [“Modic M122” manufactured by Mitsubishi Chemical Corporation]
A rotomolded container was obtained in the same manner except that the layer was formed, and the same evaluation was performed.

Example 10 In Example 2, an adhesive resin having an average thickness of 1 mm between the outer layer and the inner layer [“Modic M122” manufactured by Mitsubishi Chemical Corporation]
A rotomolded container was obtained in the same manner except that the layer was formed, and the same evaluation was performed.

Example 11 In Example 3, an adhesive resin having an average thickness of 1 mm between the outer layer and the inner layer [“Modic M122” manufactured by Mitsubishi Chemical Corporation]
A rotomolded container was obtained in the same manner except that the layer was formed, and the same evaluation was performed.

Example 12 A molded container was obtained in the same manner as in Example 1 except that the component (C) was not contained, and the same evaluation was performed.

Example 13 A molded container was obtained in the same manner as in Example 2 except that the component (C) was not contained, and the same evaluation was performed.

Example 14 A molded container was obtained in the same manner as in Example 3 except that the component (C) was not contained, and the same evaluation was performed.

Example 15 A molded container was obtained in the same manner as in Example 1 except that the contents of the components (A) and (B) were changed to 90 parts and 10 parts, respectively, and the same evaluation was performed. The boron content in the resin composition was 210 ppm, and the sodium content was 1 ppm.
It was 00 ppm.

Example 16 A molded container was obtained in the same manner as in Example 1 except that the contents of the components (A) and (B) were changed to 70 parts and 30 parts, respectively, and the same evaluation was carried out. The boron content in the resin composition was 160 ppm, and the sodium content was 8 ppm.
It was 0 ppm.

Comparative Example 1 A molded container was obtained in the same manner as in Example 1 except that the component (B) was not contained in the resin composition, and the same evaluation was performed.

Table 1 summarizes the evaluation results of the examples and comparative examples.

[0073]

[0074]

The rotary-molded container of the present invention is excellent in drop impact resistance, interlayer adhesion, etc. since the composition containing EVOH and polyamide resin is used for the inner layer. It is useful as a container for solvents, various industrial chemicals, tanks, bottles, drums, etc., especially gasoline tanks for automobiles, containers for transportation, drums for storage and transfer
It is useful for bottles for chemicals and pesticides.

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

[Procedure amendment]

[Submission date] May 7, 2002 (2002.5.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

Example 1 EVOH containing 0.2% boric acid (C) [ethylene content: 34 mol%, degree of saponification: 99.5 mol%, MFR: 3 g
/ 10 min (210 ° C., load 2160 g), containing 400 ppm of sodium acetate] (A) 85 parts and polyamide resin [“Grillon CF6S” manufactured by EMS Japan Co., copolymer of nylon 6/12, density 1.05 g / cm 3 133 ° C., ΔH51 J / g, MFR 18 g / 10 min (2
10 ° C., and molten kneading Te to load 2160g)] (B) 15 parts biaxial extruder, the composition used for the inner layer [boron 300
ppm, sodium 95 ppm].

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction contents]

Example 2 EVOH containing 0.13% of boric acid (C) [ethylene content 29 mol%, saponification degree 99.6 mol%, MFR 1
5 g / 10 min (210 ° C., load 2160 g), containing 400 ppm of sodium acetate, containing 90 ppm of potassium acetate] (A) 85 parts and a polyamide resin [“Grillon CF6S” manufactured by EMS Japan Co., a copolymer of nylon 6/12, Density 1.05 g / cm3, melting point 133 ° C, ΔH5
1 J / g, MFR 18 g / 10 min (210 ° C., load 21
60 g)] (B) 15 parts by molten kneading Te in a twin-screw extruder, the composition of the inner layer [boron 195ppm containing, sodium 95ppm containing, similarly rotated except that to obtain a potassium 30ppm containing] from Example 1 A molded container was obtained and similarly evaluated.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction contents]

Example 3 EVOH containing 0.13% of boric acid (C) [ethylene content 38 mol%, saponification degree 99.6 mol%, MFR 3
g / 10 min (210 ° C., load 2160 g), containing 336 ppm of sodium acetate, sodium dihydrogen phosphate 92p
pm, 230 ppm calcium acetate] (A) 8
5 parts and polyamide-based resin ["Grillon CF6S" manufactured by EMS Japan Co., nylon 6/12 copolymer, density 1.05 g / cm3, melting point 133 ° C, ΔH51J / g,
MFR 18 g / 10 min (210 ° C., load 2160 g)]
(B) 15 parts by molten kneading Te biaxial extruder, the resin composition [boron 195ppm containing, sodium 95ppm containing calcium 50ppm containing except that afford the Example 1
In the same manner as in the above, a rotomolded container was obtained and evaluated in the same manner.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 29/04 B29K 29:00 77:00) B29L 22:00 B29K 29:00 B65D 1/00 B B29L 22:00 F term (reference) 3E033 BA21 BA24 BB08 CA09 CA11 CA16 CA18 FA10 4F205 AA19 AA29 AB16 AG03 AH55 GA03 GB01 GB22 GC04 GF01 GF02 4J002 BB221 BE031 CL032 CL052 GF00 GG01

Claims (4)

[Claims] An outer layer is made of a thermoplastic resin, and an inner layer is made of ethylene resin.
A rotary-molded container comprising a composition containing a saponified vinyl acetate copolymer (A) and a polyamide resin (B). 2. The melting point of the polyamide resin (B) is 160 ° C.
The rotomolded container according to claim 1, wherein: 3. A weight ratio (A / A) of a saponified ethylene-vinyl acetate copolymer (A) and a polyamide resin (B).
3. The rotomolded container according to claim 1, wherein B) is 50/50 to 99/1. 4. The composition according to claim 1, further comprising boron or a boron compound (C).
3. The rotomolded container according to any one of 3.