PLASTIC BARRIER LAMINATE WITH AN AT LEAST PARTIALLY CRYSTALLIZED LAYER AND WITH A PIGMENTED LAYER

Abstract

A plastic barrier laminate having at least one at least partially crystallized layer containing polyethylene and a nucleating agent, and at least one pigmented layer containing polyethylene and a portion of flake-shaped pigments, wherein the portion of pigments is in the range from 1.5% by weight to 5.0% by weight relative to the weight of the at least one pigmented layer.

Claims

1-15. (canceled)

16. A plastic barrier laminate comprising at least one at least partially crystallized layer containing polyethylene and a nucleating agent, and at least one pigmented layer containing polyethylene and a portion of flake-shaped pigments, wherein the portion of pigments is in the range from 3.0% by weight to 8.0% by weight relative to the weight of the at least one pigmented layer.

17. The plastic barrier laminate according to claim 16, wherein the at least one at least partially crystallized layer contains 1.5% by weight to 5% by weight of the nucleating agent relative to the weight of the partially crystallized layer.

18. The plastic barrier laminate according to claim 17, wherein the plastic barrier laminate contains at least two at least partially crystallized layers, each of these layers containing polyethylene and a nucleating agent, wherein at least one of the at least one pigmented layer is arranged between the at least two at least partially crystallized layers.

19. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate contains at least two at least partially crystallized layers, each of these layers containing polyethylene and a nucleating agent, wherein at least one of the at least one pigmented layer is arranged between the at least two at least partially crystallized layers.

20. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate contains at least two pigmented layers, each of these pigmented layers containing polyethylene and a portion of flake-shaped pigments, wherein the portion is in the range from 3.0% by weight to 8.0% of weight relative to the weight of the respective pigmented layer, wherein at least one of the at least one at least partially crystallized layer is arranged between the at least two pigmented layers.

21. The plastic barrier laminate according to claim 16, wherein the at least one pigmented layer, except for inevitable impurities, only contains polyethylene and flake-shaped pigments.

22. The plastic barrier laminate according to claim 16, wherein the polyethylene of the at least one pigmented layer contains at least one of the following polyethylene materials: high density polyethylene medium density polyethylene a blend of high density and medium density polyethylene.

23. The plastic barrier laminate according to claim 16, wherein the polyethylene of the at least one pigmented layer consists of at least one of the following polyethylene materials: high density polyethylene medium density polyethylene a blend of high density and medium density polyethylene.

24. The plastic barrier laminate according to claim 16, wherein at least one of the at least one pigmented layer contains two different types of polyethylene which differ in their density.

25. The plastic barrier laminate according to claim 16, wherein the at least one at least partially crystallized layer, except for inevitable impurities, only contains polyethylene and the nucleating agent.

26. The plastic barrier laminate according to claim 16, wherein the polyethylene of the at least one at least partially crystallized layer contains high density polyethylene.

27. The plastic barrier laminate according to claim 16, wherein the polyethylene of the at least one at least partially crystallized layer consists of high density polyethylene.

28. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate consists of at least 90% by weight of polyethylene.

29. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate consists of at least 95% by weight of polyethylene.

30. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate additionally comprises a gas transmission barrier polymer layer.

31. The plastic barrier laminate according to claim 30, wherein the plastic barrier laminate contains at least two at least partially crystallized layers, each of these layers containing polyethylene and a nucleating agent, wherein the gas barrier polymer layer is arranged between two of the at least two at least partially crystallized layers.

32. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate additionally comprises an oxygen transmission barrier polymer layer wherein the oxygen transmission barrier polymer comprises at least one of ethylene vinyl alcohol and polyvinyl alcohol.

33. The plastic barrier laminate according to claim 30, wherein the plastic barrier laminate contains at least two pigmented layers, each of these pigmented layers containing polyethylene and a portion of flake-shaped pigments, wherein the portion is in the range from 3.0% by weight to 8.0% of weight relative to the weight of the respective pigmented layer, wherein the gas barrier polymer layer is arranged between the at least two pigmented layers.

34. The plastic barrier laminate according to claim 16, wherein the plastic barrier laminate contains a plurality of pigmented layers, each of these pigmented layers containing polyethylene and a portion of flake-shaped pigments, wherein the plurality of pigmented layers are arranged immediately subsequent to one another in a stacking direction of the plastic barrier laminate, in which the layers of the plastic barrier laminate are stacked to form the multi-layer plastic barrier laminate.

35. A tube body for a flexible tube container, comprising or being formed of the plastic barrier laminate according to claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail and illustrated in the accompanying drawings which forms a part hereof and wherein:

[0063] FIG. 1 a schematic perspective view of an exemplary tube container as described above, having a tube body formed of a plastic barrier laminate of the present application,

[0064] FIG. 2 a schematic sectional view of a first embodiment of the plastic barrier laminate suitable to form the tube body of the tube container of FIG. 1, and

[0065] FIG. 3 a schematic sectional view of a second embodiment of the plastic barrier laminate also suitable to form the tube body of the tube container of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0066] Referring now to the drawings wherein the showings are for the purpose of illustrating preferred and alternative embodiments of the invention only and not for the purpose of limiting the same, FIG. 1 depicts in schematic perspective view a tube container that is known in the art as such. The tube container is generally labeled by reference numeral 10. The tube container 10 has a tube body 12, which is known per se, formed of a straight or curved rectangular blank sheet of a plastic barrier laminate 14. The blank sheet of plastic barrier laminate 14 is rolled to a cylindrical or conical tube. The rolled blank sheet is overlapped at its circumferential end portions and the overlapping portions are sealed by a longitudinal seam 16 shown in FIG. 1. The thus formed hollow tube blank is sealed on one longitudinal end 12a by sealing opposing inside surface portions of the tube blank, which are facing each other, with each other to form a cross seam 18. Thereby the tube body 12 is received.

[0067] “Sealing” in the context of the present application means heat sealing.

[0068] On the respective other longitudinal end 12b the tube body 12 surrounds a shoulder part 20. The shoulder part 20 is sealed to the inner surface of the tube body 12. The shoulder part 20 has a neck portion 20a which has an opening that is not shown in FIG. 1. Through the neck portion 20a and its opening content can be released from the tube container 10.

[0069] When the tube container is not needed, a cap 22 closes the opening in the neck portion 20a. Usually the neck portion 20a is formed with an outer thread on and off which the cap 22 can be screwed by an integral sleeve (not shown in FIG. 1) formed inside the cap 22 and having an inner thread formed on its inside.

[0070] The shoulder part 20 is drawn in FIG. 1 by dashed lines as it lies behind the tube body 12 and the cap 22 and cannot directly be seen from the observer FIG. 1.

[0071] FIG. 2 depicts a schematic cross-section of a first possible embodiment of the plastic barrier laminate 14 suitable to form the tube body 12 of FIG. 1.

[0072] The plastic barrier laminate 14 has an exposed outer surface 14a, which forms the outer surface of the tube body 12, and has an exposed inner surface 14b, which forms the inner surface of the tube body 12 and which is in direct contact with the content by which the tube 10 is filled.

[0073] The plastic barrier laminate 14 is just exemplary and may contain additional polymer, in particular polyethylene, layers and/or ink layers, the latter being particularly preferably formed by printing.

[0074] The outermost layer of the exemplary plastic barrier laminate 14 can be formed by a sealable layer 24 of linear low density polyethylene (LLDPE), preferably in a thickness range from 8 to 30 μm. Besides being sealable, the LLDPE layer 24 provides a glossy outer surface and consequently a good optical appearance. The LLDPE layer 24 can be transparent or can be colored by pigments dispersed in the LLDPE material.

[0075] The outermost layer 24 on its side facing towards the later inside of the tube container 10 is bonded to a first moisture vapor transmission rate barrier layer 26.

[0076] This first MVTR barrier layer 26 contains an HDPE material as a first PE material with a share of 63% by weight related to the entire weight of the first MVTR layer 26. The HDPE material has a melt index of 0.75 g per 10 min. The first MVTR barrier layer 26 contains a MDPE material as a second PE material with a share of also 34% by weight related to the entire weight of the first MVTR layer 26. The shares, in particular of the PE materials are only exemplary and need not be equal by amount.

[0077] The first MVTR barrier layer 26 further contains a barrier nucleating agent, for example the nucleating agent “Hyperform® HPN-20E” by Milliken Chemical Company in USA, with a share of 3% by weight related to the entire weight of the first MVTR layer 26. By use of this barrier nucleating agent the HDPE material of the first MVTR barrier layer 26 is largely crystallized, e. g. has a content of crystallized PE of more than 50% by weight. Consequently, the first MVTR barrier layer 26 is an at least partially crystallized layer in the sense of the above introductory portion of this application.

[0078] The first MVTR barrier layer 26 has a thickness in the range of 8 to 60 μm, and preferably has a thickness of 10 μm.

[0079] Further following from the outside to the inside along the stacking direction S of the plastic barrier layer 14 the plastic barrier layer 14 contains an extruded polyethylene layer 28 serving as a bonding layer to connect the first MVTR barrier layer 26 to a first gas transmission rate barrier layer 30.

[0080] The first GTR barrier layer 30 comprises only the MDPE also contained in the first MVTR barrier layer 26. It further comprises a share of 15% by weight of the entire first GTR barrier layer 30 of a flake-shaped silver-colored master batch as available by Ampacet Corporation, USA, under the tradename of “FauxFoil™”. This master batch has a pigment content of approximately 35% by weight of the master batch. Consequently, the first GTR barrier layer 30 has share of flake-shaped pigments of about 5.25% by weight related to the entire weight of the first GTR barrier layer 30. Given that the matrix material of the master batch is polyethylene, for example LLDPE, to ensure a proper blend of the master batch with the receiving polymer material, the assumption of equal or at least very similar densities of the master batch on the one hand and of the receiving MDPE material on the other hand is adequate. Consequently, the flake-shaped pigment content of the first GTR barrier layer 30 can with sufficient certainty be calculated by multiplying the pigment content of the master batch by the master batch content of the first GTR barrier layer 30.

[0081] The content of the second HDPE material within the first GTR barrier layer 30 is 85% by weight related to the entire weight of the first GTR barrier layer 30, so that the second HDPE material, the flake-shaped pigments and the matrix material of the master batch add up to a total of 100% per weight.

[0082] The first GTR barrier layer 30 has a thickness in the range of 10 to 40 μm, and preferably has a thickness of 14 μm.

[0083] In the stacking direction S, on the side facing away from the bonding PE layer 28 a second GTR barrier layer 32 and a third GTR barrier layer 34 are arranged. The second and third GTR barrier layers 32 and 34, to facilitate the explanation, are identical to the first GTR barrier layer 30. However, the second and third GTR barrier layers 32 and 34 may differ in at least one of thickness, MDPE content and HDPE content, melt index and pigment content within the given ranges above in the introductory portion.

[0084] The first to third GTR barrier layers 30, 32 and 34 in the present example are coextruded and together form a GTR barrier film 36.

[0085] On the side facing away from the second GTR barrier layer 32 another extruded bonding layer 38 of PE is extruded, in order to bond a second MVTR layer 40 to the GTR barrier film 36.

[0086] Although not necessarily so, for the present example it is sufficient that the second MVTR layer 40 is identical to the first MVTR layer 26.

[0087] The inner surface 14b of the plastic barrier laminate 14 is formed by an innermost sealable HDPE layer 42 that is extruded or laminated to the second MVTR layer 40.

[0088] The innermost sealable HDPE layer 42 has a thickness in the range of 20 to 40 μm, and preferably has a thickness of 30 μm.

[0089] Instead of the sealable HDPE layer, the innermost layer 42 could be formed by a layer that is identical to the LLDPE layer 24 which forms the outermost layer of the plastic barrier laminate 10. In this case the construction of the plastic barrier laminate 10 would be mirror symmetrical with respect to the central layer, which is the second GTR barrier layer 32.

[0090] The plastic barrier laminate 14 has an oxygen transmission rate of less than 0.1 cm.sup.3/(m.sup.2.Math.d) according to ASTM D 3985-02, in a test environment of 23° C. and 0% relative humidity. It further has a water vapor transmission rate of less than 1.0 g/(m.sup.2.Math.d) according to ASTM F 1249-01 in a test environment of 38° C. and 90% relative humidity.

[0091] The plastic barrier laminate 14 is free of metal foil and is further free of polyamide, and besides inevitable impurities only contains polyethylene as polymer. It is therefore easy to recycle and can be treated as monomaterial in a recycling process.

[0092] FIG. 3 shows a second embodiment of the plastic barrier laminate 114 that is suitable to form the tube body 12 of FIG. 1.

[0093] Features that are identical in structure and/or function to features of FIG. 2 are labeled with the same reference numerals in FIG. 3, but in the number space from 100 to 199. The second embodiment of FIG. 3 will in the following be explained only to the extent to which it differs from the first embodiment of FIG. 2. The explanation of FIG. 2 otherwise applies also to FIG. 3 with regard to the features labeled with the same reference numerals but increased by 100.

[0094] The plastic barrier laminate 114 differs from the plastic barrier laminate 14 in FIG. 2 in that it has a third MVTR barrier layer 144, which is identical to the first and second MVTR barrier layers 126 and 140. For that reason reference is made to the above explanation of the first MVTR barrier layer 26 which also applies to each MVTR barrier layer 126, 140 and 144.

[0095] Between the second and third MVTR barrier layers 140 and 144, respectively, an additional gas barrier polymer layer 146 made of ethylene vinyl alcohol copolymer (EVOH) is arranged. The additional gas barrier polymer layer 146 is bonded to the second MVTR barrier layer 140 by a first tie layer 148 of maleic anhydride grafted polyethylene and is bonded to the third MVTR barrier layer 144 by a second tie layer 150 which is identical to the first tie layer 148.

[0096] The additional gas barrier polymer layer 146 has a thickness in the range of 5 to 9 μm, and has a preferred thickness of 7 μm. the tie layers 148 and 150 have a thickness in the range of 2 to 6 μm, and have a preferred thickness of 4 μm.

[0097] By additionally providing the additional gas barrier polymer layer 146 and the third MVTR barrier layer 144, the gas transition barrier properties and the moisture vapor transmission barrier properties can be further enhanced compared to the first embodiment in FIG. 2. Additionally providing the third MVTR barrier layer 144 improves prevailingly the moisture vapor transmission barrier properties of the plastic barrier laminate 114, additionally providing the additional gas barrier polymer layer 146 improves prevailingly the gas transmission barrier properties.

[0098] While considerable emphasis has been placed on the preferred embodiments of the invention illustrated and described herein, it will be appreciated that other embodiments, and equivalences thereof, can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. Furthermore, the embodiments described above can be combined to form yet other embodiments of the invention of this application. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.