WO2002038377A1

WO2002038377A1 - Extrusion-molded hollow container made of polyethylene

Info

Publication number: WO2002038377A1
Application number: PCT/JP2001/009707
Authority: WO
Inventors: Peter Frisk
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 2000-11-09
Filing date: 2001-11-07
Publication date: 2002-05-16
Also published as: AU2002212713A1

Abstract

An extrusion-molded hollow polyethylene container which is a layered product comprising a layer comprising a copolymer of a polycyclic olefin, a layer comprising high-density polyethylene, an adhesive layer, a layer comprising an aromatic polyamide resin, an adhesive layer, and a layer of linear low-density polyethylene, the layer of linear low-density polyethylene being the innermost layer of the container. The container is excellent in barrier properties and aroma retention and is environmentally satisfactory. It is useful for packing, e.g., a high-quality liquid food to which flavor is important.

Description

Description Extrusion hollow molded container made of polyethylene Technical field

TECHNICAL FIELD The present invention relates to a polyethylene extruded hollow molded container, and more particularly, to a polyethylene extruded hollow molded container for liquid foods and the like which exhibits excellent barrier resistance and aroma-preserving properties and is environmentally friendly. Background art

Conventionally, high-density polyethylene containers have been used as extruded hollow molded containers for liquid foods such as milk, juice, coffee, and alcoholic beverages, but the fragrance of high-grade liquid foods is maintained during storage. It is strongly required to be done. High-grade liquid foods that emphasize fragrance, such as fragrance components that are oxidized during storage, absorbed by the materials of surrounding containers, or transferred to the filling in the materials of surrounding containers, and the fragrance is Will be impaired. In such containers, the oxygen barrier layer of the fragrance component to protect the fragrance component from oxidation etc. is provided as close as possible to the contents that are high-grade liquid foods. No. The shielding layer is also important for the strength of the container, but if the shielding layer is too thick, the container will become brittle.

In order to protect the scent of the contents, in a high-density polyethylene extruded hollow molded container, a container with a very high-density polyethylene layer, and a container with a low-density polyethylene layer inside the high-density polyethylene layer Further, a container provided with an inner layer composed of a high-density polyethylene layer and a barrier layer such as an ethylene-butyl alcohol copolymer or nylon 6 has been tried.

However, in the container in the above-mentioned attempt, the fragrance component of the content cannot be sufficiently protected. Disclosure of the invention An object of the present invention is to provide a polyethylene extruded hollow molded container that is filled with a high-grade liquid food or the like that exhibits excellent barrier resistance and fragrance retention, is environmentally friendly, and emphasizes good fragrance. .

The present inventors have conducted intensive studies to improve the above-mentioned problems, and as a result, a polyamide resin layer containing an aromatic polyamide resin inside a high-density polyethylene layer containing already used high-density polyethylene which has been recycled, etc. The inventors have found that the object of the present invention can be achieved by providing a linear low-density polyethylene layer inside, and have reached the present invention.

That is, the present invention relates to a laminate comprising a polycyclic olefin copolymer-containing layer, a high-density polyethylene-containing layer, an adhesive layer, an aromatic polyamide resin-containing layer, an adhesive layer, and a linear low-density polyethylene layer laminated in that order. The linear low-density polyethylene layer forms the innermost layer of a container, and has a gist of a polyethylene extruded hollow molded container (hereinafter, referred to as a container 1), which is characterized by being formed.

The present invention comprises a laminate in which a high-density polyethylene-containing layer, an adhesive layer, an aromatic polyamide resin-containing layer, an adhesive layer, a polycyclic olefin copolymer-containing layer, and a linear low-density polyethylene layer are laminated in this order. The straight-line low-density polyethylene layer forms the innermost layer of the container, and has a gist of a polyethylene extruded hollow molded container (hereinafter, referred to as container 2), which is characterized by being formed.

The present invention comprises a laminate in which a high-density polyethylene-containing layer, an adhesive layer, an aromatic polyamide resin-containing layer, an adhesive layer, and a layer containing a linear low-density polyethylene and a polycyclic olefin copolymer are laminated in that order. The layer containing the linear low-density polyethylene and the polycyclic olefin copolymer forms the innermost layer of a container, and is characterized by a polyethylene extruded hollow molded container (hereinafter, referred to as container 3). You.

The container 13 of the present invention is characterized in that the high-density polyethylene-containing layer comprises a mixture layer of unused (purged) high-density polyethylene and used (recycled) high-density polyethylene. The container 13 of the present invention is characterized in that the aromatic polyamide resin-containing layer is a polyamide resin layer containing at least 70% by mass of an aromatic polyamide resin.

The container 13 of the present invention is characterized in that the linear low-density polyethylene is a linear low-density polyethylene produced by using a metallocene catalyst.

The container 1, the container 2 and the container 3 of the present invention are characterized in that the polycyclic olefin copolymer is a copolymer of a polycyclic olefin and ethylene or α-olefin. BEST MODE FOR CARRYING OUT THE INVENTION

The high-density polyethylene of the high-density polyethylene layer forming the container 13 of the present invention is a melt flow index (ΜFI: 190 ° C., load: 2.16 kg) used for polyethylene bottles. Can be used for about 0.1-3 g / 10 minutes. The high-density polyethylene may be only virgin (unused) high-density polyethylene, but a mixture of virgin (unused) high-density polyethylene and recycled (used) high-density polyethylene forms an environmental burden. Desirable in terms of reduction. Examples of the high-density polyethylene used include those that can be separated and collected from discarded high-density polyethylene and that can be recycled, and those that are discharged as scrap from factories and the like. The content of the high-density polyethylene used in the mixture is preferably 30% by mass or less. The thickness of the high-density polyethylene layer is preferably 300-500 μπι.

The aromatic polyamide resin-containing layer forming the container 13 of the present invention is preferably a mixture layer of an aromatic polyamide resin and a polyamide resin other than the aromatic polyamide resin. The content of the group III polyamide resin is preferably at least 70% by mass.

Examples of the aromatic polyamide resin include polyamide MX D6, polyhexamethylene diamine terephthalate (polyamide 6T), polyhexamethylene diamine isophthalamide, and a polyamide containing a xylene group. D6 is particularly preferred. Polyamide resins other than aromatic polyamide resins include aliphatic polyamides such as polyamide 4-6, polyamide 6, polyamide 6-6, polyamide 6_10, polyamide 6_12, polyamide 11 and polyamide 12. And polyamide 6 and polyamide 6-6 are particularly preferred. The thickness of the aromatic polyamide resin-containing layer is preferably from 30 to 50 μπι.

The linear low-density polyethylene layers forming the containers 1 and 2 of the present invention and the linear low-density polyethylene and the polycyclic olefin copolymer-forming layer forming the container 3 have a linear low density. Examples of high-density polyethylene include α-olefins having ethylene and a comonomer having 4 to 10 carbon atoms, for example, 1-butene, 1-hexene, 4-methyl-1- Although those manufactured by copolymerizing pentene, 1-heptene, 1_ otaten, etc. can be used, linear low-density polyethylene (mLLDPE) manufactured by using a meta-mouth catalyst is particularly preferable. .

mLLDPE is an α-olefin having ethylene and a comonomer having 418 carbon atoms, preferably 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-otaten in the presence of a meta-mouth catalyst. It is preferable to use a polymer produced by copolymerizing α-olefin having 6 or more carbon atoms, such as α-olefin.

The above-mentioned meta-mouth catalyst is a compound having a structure in which a transition metal such as titanium, zirconium, or hafnium is sandwiched by an unsaturated cyclic compound containing a 7-electron cyclopentenyl group or a substituted cyclopentenyl group. And a cocatalyst such as an aluminum compound such as an alkyl aluminoxane, an alkyl aluminum, an aluminum octalide, or an alkyl amine dihalide.

m LLD Ρ が has a narrow molecular weight distribution of 2 to 4 in weight average molecular weight and number average molecular weight, and has a density of 0.900 to 0.925 gZcm ³ , but a density of 0.900 to 0.90. Those having 915 g / cm ³ are preferred. In addition, MF I (190T: load 2.16 kg) force S 10-20 gZl 0 min is preferable. Such mLLDP E has very strong strength and good processability, and by using this, Shows very good shape retention. The thickness of the linear low-density polyethylene layer is preferably from 200 to 500 m.

The polycyclic olefin copolymer layer forming the containers 1 and 2 of the present invention and the polycyclic olefin copolymer of the layer containing the linear low-density polyethylene and the polycyclic olefin copolymer forming the container 3 are And copolymers of polycyclic olefins and ethylene or α-olefin, copolymers of polycyclic olefins and monocyclic olefins, and copolymers of polycyclic olefins and non-conjugated gens. A copolymer of polycyclic olefin and ethylene or olefin, particularly a copolymer of polycyclic olefin and ethylene is preferred.

The polycyclic Orefin, bicyclo [2, 2, 1] - hept - 2 E emissions and derivatives thereof, tetracyclo [4, 4, 0, l 2 '5, I 7' 10] - 3- dodecene and its of derivatives, to Kisashikuro [6, 6, 1, 1 3 '6, 1 10' 13, O 2 '7, 0 9' 14] - 4- heptadecene and derivatives thereof, O click evening cyclo [8, 8, 0, ^{^{^{l 2 '9, l' 7}}} , I 11 '10, l 13' 16, O 3 '8, 0 12' 17] - 5- docosenoic and derivatives thereof, pentacyclo [6, 6, 1, I 3 '6, 0 ^2, ^7, 0 ⁹ ^'14] - Kisadesen and derivatives thereof to 4, pentacyclo [6, 5, 1, l 3' 6, O 2 '7, 0 9' 13] - 4- pentadecene and derivatives thereof, Heputashiku port [8, 7, 0, l 2 '9, I 4' 7, I 11 '17, 0 3' 8, 0 12 '15] - 5- heneicosene and derivatives thereof, heptene evening cyclo [8, 8, ^{^{0, l 2 '9, l}} 4' 7, I 11 '16, 0 3,8, 0 12 · 17] derivative one 5_ heneicosene及Piso, tricyclo [4, 4, 0, I ² ' ⁵ ]-3-pentacene and its derivatives, tricyclo [4, 3, 0, I ² ' ⁵ ]-3-decene and its derivatives, pentacyclo [6, 5, 1, I ³ ' ⁶ , 0 ² , ^7, 0 ⁹ ^'13] - 4, 10 - penta decadiene and derivatives thereof, pentacyclo [4, 7, 0, I 2, 5, 0 8' 13, I 9 '12] - derivative 3_ pentadecene及Piso , heptacyclo [7, 8, 0, I 3 '5, l 2' 7, l 10 '17, 0 11' 16, 0 12 '15] - 4- eicosene and derivatives thereof, Nonashikuro [10, 1, I ⁴ ^{^{^{'7, 0 3' 8,}}} 0 2 '10, 0 12, 21, I 13' 20, 0 14 '19, 0 15' 19] - 5- pen evening Sekong and derivatives thereof. Α-olefins copolymerized with polycyclic olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methinole-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like. Examples of the monocyclic olefin include cyclobutene, cyclopentene, cyclohexene, 3-methylcyclohexene, cyclooctene and the like. Examples of the non-conjugated gen include 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 1,7-octadiene. One or more of these olefins that are copolymerized with the polycyclic olefin can be used.

The copolymerization of the polycyclic olefin and the above olefins is usually carried out in the presence of a medium such as an organic solvent using a catalyst in which a transition metal compound such as titanium, zirconium, vanadium or hafnium is combined with an organic aluminum compound. In the absence, carried out at a temperature of-50-150 ° C. The polycyclic olefin copolymer used in the present invention produced by the above-mentioned copolymerization is a random copolymer of the polycyclic olefin and the above-mentioned olefins, and the structural unit derived from the polycyclic olefin is 30%. one 9 5 mol ^_0/0, especially 4 0 8 0 mole ⁰ do things Shi preferred Rere.

The polycyclic olefin copolymer-containing layer forming the containers 1 and 2 may be a mixture layer with another substance, but is preferably a single layer of the polycyclic olefin copolymer. As a substance that can be mixed with the polycyclic olefin copolymer, polyethylene, polypropylene, ethylene-propylene copolymer, polyolefin such as polybutene-1, particularly polyethylene is preferable. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. When another substance is mixed with the polycyclic olefin copolymer, the other substance is preferably 50% by mass or less, particularly preferably 40% by mass or less.

The content of the polycyclic olefin copolymer in the layer containing the linear low-density polyethylene and the polycyclic olefin copolymer forming the container 3 is 50% by mass or less, particularly 60-80% by mass. It is preferred that Linear low-density polyethylene, especially m LLDPE, and polycyclic olefin copolymers are easily mixed and compatible. The thickness of the polycyclic olefin copolymer layer forming the containers 1 and 2 is preferably from 200 to 500; m. Further, the thickness of the layer containing the linear low-density polyethylene and the polycyclic olefin copolymer forming the container 3 is preferably 20000 μπι.

The adhesive layer for bonding each layer of each container of the present invention is an adhesive that can be used when manufacturing a laminate constituting each container by hollow extrusion molding, for example, an acrylic resin Adhesives, modified polyolefin adhesives, ethylene-vinyl acetate copolymer, polyamide adhesives, epoxy resin adhesives, and the like. Examples of the acryl resin-based adhesive include polymers and copolymers of acrylic acid or methacrylic acid or alkyl esters thereof. Examples of the modified polyolefin adhesive include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, nadic acid, and nadic acid anhydride such as polyethylene and polypropylene, or anhydrides thereof. In the presence of an organic peroxide. The thickness of the adhesive layer is preferably from 30 to 50 μπι. Each container of the present invention can be manufactured by melting and extruding the above-mentioned components forming each layer by an in-die laminating method or an out-of-die laminating method so as to form the hollow layers so that the above-mentioned layers are in that order. it can. The thickness of each container of the present invention is usually set at 600 μm—1.2 mm. Example

Hereinafter, the present invention will be described in detail with reference to Examples.

(Example 1)

30 / xm polycyclic olefin copolymer-containing layer containing polycyclic olefin copolymer (60 mol% of polycyclic olefin component, 40 mol% of ethylene component), high-density polyethylene (MFI: 2 gZl 0 Min.) 70% by mass and high-density polyethylene recovered from waste high-density polyethylene 30% by mass Mixed high-density polyethylene, modified polyolefin adhesive (trade name: Vineel 428, manufactured by Dupont), 7 A mixture of 5% by weight of polyamide MX D6 and 25% by weight of polyamide 6, the above adhesive and a density of 0.910 gZ cm ³ , MFI: 14 gZ 10 mL LDPE 10 min. Extruded to form a bottle-shaped hollow molded body with the mixed high-density polyethylene layer 300 m, the adhesive layer 30 fim, the polyamide resin mixture layer 30, the adhesive layer 30 m and the innermost layer as the above-mentioned mLLDPE layer 200 m ( Container 1) was molded.

(Example 2)

A polycyclic olefin copolymer containing layer (60 mol% of a polycyclic olefin component, 40 mol% of an ethylene component) so as to provide a layer containing a polycyclic olefin copolymer of 30 zm between the adhesive layer and the mLLDPE layer. A bottle-shaped hollow molded body (container 2) was formed in the same manner as in Example 1 except that the above-mentioned was used.

(Example 3)

Example 2 Example 5 was repeated except that a mixture of 65% by mass of the m LLDPE and 35% by mass of the polycyclic olefin copolymer was used instead of the mLLDPE and the polycyclic olefin copolymer used in Example 1. In the same manner as in 1, a pottle-shaped hollow molded body (container 3) having a thickness of 200 m of the mixture layer of the mLLDPE and the polycyclic olefin copolymer was formed.

(Comparative Example 1)

The high-density polyethylene used in Example 1 was melt-extruded to form a pot-like hollow molded body having a thickness of 1.0 mm.

(Comparative Example 2)

Polyamide 6 was prepared in the same manner as in Example 1 except that the polyolefin copolymer was not used, polyamide 6 was used instead of the polyamide MXD 6 and polyamide 6 mixture, and low-density polyethylene was used instead of mLLDPE. The barrier resistance of the 20 bottles obtained in Examples and Comparative Examples in which a bottle-shaped hollow molded article having a layer thickness of 50 im and a low-density polyethylene layer of 500 m was molded was evaluated for the oxygen permeation amount. (Cc · 24 hours · 101.3 kPaZ1 container) was evaluated. The results are as follows.

Oxygen transmission

Example 1 0.01 -0.03

2 0.008-0.010

3 0.02--0.05

1 0.2-0.5

2 0.05 -0.08 As is clear from the above, it is understood that the bottle obtained in the example has much better i-barrier property than the bottle obtained in the comparative example. advantage

The container 1 of the present invention shows excellent barrier properties and fragrance retention properties by the aromatic polyamide resin of the aromatic polyamide resin-containing layer, and the linear low density polyethylene of the innermost layer, especially mL LDPE, Due to its extremely high strength, the container shows good shape retention and durability when the liquid filling is filled at a high temperature, even if its thickness is less than 250 m.

The containers 2 and 3 of the present invention exhibit the same effects as those of the container 1, and the polycyclic olefin copolymer of the layers constituting the containers has a very good moisture barrier property. As a result, the moisture barrier property has been improved, and since it has very good transparency, it can be made into a transparent container comparable to glass, and it has excellent compatibility with linear low-density polyethylene, especially mL LDPE. Because of its excellent heat resistance, the bonding between the linear low-density polyethylene layer and the polycyclic olefin copolymer layer does not require an adhesive, and the shape retention and durability of containers when filled at high temperatures Is further improved. The hollow container according to the present invention has a significantly improved dross on the surface of the container as compared with a conventional high-density polyethylene hollow molded container, and thus has a very good appearance.

The polycyclic olefin copolymer is highly rigid, which improves the rigidity of the container.

The hollow container of the present invention has improved rigidity, luster, transparency, resistance to tearing, heat resistance, moisture resistance, etc. of conventionally used plastics and the like by the polycyclic olefin copolymer-containing layer. Means better appearance and appearance of the container.

The polycyclic olefin copolymer-containing layer has, for example, good compatibility with the constituent polyethylene layer, and improves and improves the adhesion of the polyethylene layer. As a result, the resulting container shows good integrity without delamination.

In the container of the present invention, the container molded with the layered polycyclic olefin copolymer-containing layer has excellent shape retention. Therefore, the workmanship of the container is good.

Although a layer containing a polycyclic olefin copolymer is provided as a constituent layer of the container wall, it is not necessarily clear in theory, but the mechanical strength of the other layers is complemented and the container shape is improved. Hold well. Therefore, the appearance of the container is good.

The polycyclic olefin copolymer-containing layer not only has excellent heat resistance, but also does not cause damage to the inside of the vessel wall, heat history, etc. even at a high temperature of about 130 ° C, and has an autoclave treatment and a retort. Ideal for packaging containers that need to be processed.

Since the inside of the container and the container itself are protected by the layer containing the polycyclic olefin copolymer, the integrity of the container is maintained even if the content of the filling is strong or corrosion-resistant, and the container leaks, especially at high temperatures. Does not occur.

The polycyclic olefin copolymer of the layer constituting the container of the present invention has a very good moisture barrier property, and the moisture barrier property of the container is improved. The oxygen scavenging performance of the barrier layer inside the polycyclic olefin copolymer layer can be maintained and protected. With the oxygen barrier property of the barrier layer inside the container wall, a complete barrier function can be added to the container. Industrial applicability

The hollow molded container of the present invention is used as a molded container for liquid foods such as milk, juice, coffee, and alcoholic beverages.

Claims

The scope of the claims

1. Polycyclic copolymer copolymer-containing layer, high-density polyethylene-containing layer, adhesive layer, aromatic polyamide resin-containing layer, adhesive layer and linear low-density polyethylene layer

An extruded hollow-molded container made of polyethylene, comprising a laminate laminated in order, wherein the linear low-density polyethylene layer forms the innermost layer of the container.

2. A laminated body in which a high-density polyethylene-containing layer, an adhesive layer, an aromatic polyamide resin-containing layer, an adhesive layer, a polycyclic olefin copolymer-containing layer, and a linear low-density polyethylene layer are laminated in this order. Low density polyethylene layer is the innermost layer of the container

10. An extruded hollow-molded container made of polyethylene, which is formed from

3. A laminate comprising a high-density polyethylene-containing layer, an adhesive layer, an aromatic polyamide resin-containing layer, an adhesive layer, and a layer containing a linear low-density polyethylene and a polycyclic olefin copolymer laminated in this order, The layer containing the linear low-density polyethylene and the polycyclic olefin copolymer forms the innermost layer of a container.

Extruded hollow molded container made of polyethylene.

4. The polyethylene according to any one of claims 1 to 3, wherein the high-density polyethylene-containing layer is composed of a mixture layer of unused high-density polyethylene and used high-density polyethylene. Extruded hollow molded container.

5. The method according to claim 1, wherein the aromatic polyamide resin-containing layer is a polyamide resin layer containing at least 70% by mass of an aromatic polyamide resin. Extruded hollow molded container made of polyethylene.

6. The polyethylene extrusion according to any one of claims 115, wherein the linear low density polyethylene is a linear low density polyethylene produced by using a metallocene catalyst. Hollow molded container.

25 7. The polycyclic olefin copolymer described in any one of claims 2 to 6, wherein the polycyclic olefin copolymer is a copolymer of a polycyclic olefin and ethylene or an α-old olefin. The extruded polyethylene hollow molded container according to the above.