TUBE

Description

[0001] The invention relates to a tube for containing a liquid or pasty product comprising a multi-layer tube casing, wherein the tube casing comprises one or more outer layers made of polyolefin, one or more inner layers made of polyolefin and a barrier layer arranged between the outer layer(s) and the inner layer(s), wherein the barrier layer consists of an ethylene-vinyl alcohol copolymer (EVOH).

[0002] Plastic tubes are used, for example, in the cosmetics and personal care industries as containers for liquid or pasty products. Tubes are used, for example, to hold toothpaste, creams, and the like. Tubes are also used in the pharmaceutical industry to hold creams or gels containing active pharmaceutical ingredients.

[0003] However, with plastic tubes, there is a risk that the products stored in the tube or their volatile components will diffuse through the plastic. This can lead to drying out of the product, a loss of flavorings, or a reduced effectiveness of pharmaceutical ingredients, at least during extended storage.

[0004] Plastic tubes designed to prevent the tube contents, or parts thereof, from diffusing through the tube jacket have a tube jacket consisting of an outer layer made of a polyolefin, an inner layer also made of a polyolefin, and a barrier layer. The barrier layer can be made of an ethylene-vinyl alcohol copolymer (EVOH). The tube shoulder is bonded to the tube jacket produced in this way. This tube shoulder is also made of a polyolefin and is either manufactured as a separate part and then welded to the tube jacket or injection-molded onto the tube jacket.

[0005] In addition to the requirement for sufficient barrier properties, efforts are being made to minimize the weight of plastic tubes. This reduces transport costs and material consumption, which in turn reduces environmental impact. Reducing tube weight can be achieved, for example, by choosing a thinner tube jacket. However, this potentially makes the tube unstable. The thinner the tube jacket, the more likely components of the tube contents can diffuse through the tube jacket. JP2003267431 refers to a multi-layer bottle with excellent oxygen and moisture barrier properties.

[0006] The invention is therefore based on the object of providing a tube which has the lowest possible weight, but at the same time is dimensionally stable and has the best possible barrier properties.

[0007] To achieve this object, a tube of the type mentioned at the outset is further developed according to the invention in such a way that the ethylene-vinyl alcohol copolymer (EVOH) of the barrier layer has an ethylene content of < 28 mol% and the thickness of the barrier layer is ≤ 25 µm.

[0008] By choosing a specific material for the barrier layer, namely an ethylene-vinyl alcohol copolymer with an ethylene content of < 28 mol%, the invention makes it possible to design a tube that is both lightweight and sufficiently stable. The invention takes advantage of the fact that an ethylene content of < 28 mol% ensures, on the one hand, improved barrier properties of the barrier layer and, on the other hand, greater stability. It has been found that this enables a barrier layer with a thickness of only 25 µm or less without the barrier layer losing its barrier properties. In particular, the barrier properties of the barrier layer according to the invention are sufficient to accommodate conventional products in the cosmetic and / or pharmaceutical sectors, achieving a shelf life of, for example, 1 year or more.The thickness of the barrier layer can preferably be any value in the range 5-25 µm, for example, values of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 34, and 25 µm. The thickness of the barrier layer is preferably between 5 and 25 µm, more preferably between 5 and 20 µm, such as between 10 and 20 µm.

[0009] The ethylene content of the ethylene-vinyl alcohol copolymer of the barrier layer can be < 28 mol%. The lower limit of the ethylene content can be, for example, 20 mol%.

[0010] Since ethylene-vinyl alcohol copolymer does not form a mechanically strong bond with certain polyolefins, it is advantageous or even necessary to provide adhesion promoter layers between the barrier layer and the polyolefin layers. A preferred embodiment of the invention therefore provides for an adhesion promoter layer to be arranged on both sides of the barrier layer in direct contact with it.

[0011] The thickness of each adhesion-promoting layer is preferably 5-25 µm, preferably 10-20 µm. In particular, the thickness of each adhesion-promoting layer can be chosen to be equal to the thickness of the barrier layer.

[0012] In order to achieve a lightweight tube, a preferred embodiment provides that the one or more outer layer(s) have a total thickness of 80-300 µm.

[0013] Furthermore, it is preferably provided that the one or more inner layer(s) has or have a total thickness of 80-300 µm.

[0014] In particular, the total thickness of the tube jacket is 200-600 µm, preferably 300-400 µm or 200-400 µm. This total thickness can preferably be achieved by selecting the total thickness of the one or more outer layers in the range 80-300 µm, the total thickness of the one or more inner layers in the range 80-300 µm, and the thickness of the barrier layer ≤ 25 µm, in particular 10-20 µm.

[0015] It has been shown that the barrier layer according to the invention has a sufficient barrier effect even in a tube with a tube jacket thickness in the above-mentioned range.

[0016] The multi-layer tube jacket may have one or two inner layers and one or two outer layers.

[0017] The multi-layer tube jacket can have different sequences of plastic layers and can, for example, consist of the following layers: Inner layer - primer layer - barrier layer - primer layer - outer layer, Inner layer #1 - inner layer #2 - primer layer - barrier layer - primer layer - outer layer, Inner layer #1 - inner layer #2 - primer layer - barrier layer - primer layer - outer layer #1 - outer layer #2, Inner layer - primer layer - barrier layer - primer layer - outer layer #1 - outer layer #2.

[0018] The proportion of the thickness of the one or more outer layers and the proportion of the thickness of the one or more inner layers to the total thickness of the tube shell can be selected according to the respective requirements. Preferably, the total thickness of the one or more outer layers is 30-70% of the total thickness of the tube shell. Preferably, the total thickness of the one or more inner layers is 30-70% of the total thickness of the tube shell.

[0019] As is known, the tube jacket is preferably produced by coextrusion.

[0020] Regarding the material of the inner and outer layer(s), any polyolefins can be used. Examples of suitable polyolefins include polyethylene and polypropylene.

[0021] Preferably, the one or more outer layers are made of polyethylene (PE). Preferably, the one or more inner layers are made of polyethylene (PE).

[0022] In order to further increase the inherent stability of the tube jacket, it is preferred that the polyethylene of the one or more outer layers and / or the one or more inner layers has a proportion of at least 20 wt.%, preferably at least 30 wt.%, preferably at least 40 wt.%, preferably at least 50 wt.% high-density polyethylene (PE-HD) with a specific gravity between 0.935 and 0.97 g / cm 3 . In particular, it is provided that the tube jacket as a whole has a proportion of at least 20 wt.%, preferably at least 30 wt.%, preferably at least 40 wt.%, preferably at least 50 wt.% high-density polyethylene (PE-HD) with a specific gravity between 0.935 and 0.97 g / cm 3 .

[0023] The desired proportion of at least 20% by weight of high-density polyethylene (PE-HD) can be achieved, for example, in that the tube jacket, in addition to at least one outer and / or inner layer consisting of or containing high-density polyethylene (PE-HD), also has at least one inner and / or outer layer consisting of or containing a low-density polyethylene (PE-LD) with a specific weight between 0.915 g / cm 3< and 0.935 g / cm 3< or at least one inner or outer layer consisting of or containing linear low-density polyethylene (PE-LLD).

[0024] The outer diameter of the tube sleeve can be selected depending on the desired tube volume. The tube sleeve preferably has an outer diameter of 13-60 mm.

[0025] The invention is explained in more detail using the following embodiments. Example 1 : (Not according to the present invention)

[0026] A tube jacket with the following structure was produced by coextrusion: layer material thickness Outer layer 80% LLDPE, 20% LDPE 120µm barrier layer EVOH (EVAL F101B from EVAL Europe NV) with an ethylene content of 32 mol% 20µm Inner layer 50% PE-HD, 50% PE-LLD 120µm

[0027] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 20 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 300 µm. Example 2 : (Not according to the present invention)

[0028] A tube jacket with the following structure was produced by coextrusion: layer material thickness Outer layer 80% LLDPE, 20% LDPE 220µm barrier layer EVOH (EVAL F101B from EVAL Europe NV) with an ethylene content of 32 mol% 20µm Inner layer 50% PE-HD, 50% PE-LLD 220µm

[0029] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 20 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 500 µm. Example 3:

[0030] layer material thickness Outer layer 80% LLDPE, 20% LDPE 135µm barrier layer EVOH (EVAL L171B from EVAL Europe NV with an ethylene content of 27 mol%) 10µm Inner layer 50% PE-HD, 50% PE-LLD 135µm

[0031] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 10 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 300 µm. Example 4:

[0032] A tube jacket with the following structure was produced by coextrusion: layer material thickness Outer layer 80% LLDPE, 20% LDPE 235µm barrier layer EVOH (EVAL L171B from EVAL Europe NV with an ethylene content of 27 mol%) 10µm Inner layer 50% PE-HD, 50% PE-LLD 235µm

[0033] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 10 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 500 µm. Example 5:

[0034] A tube jacket with the following structure was produced by coextrusion: layer material thickness Outer layer 80% LLDPE, 20% LDPE 120µm barrier layer EVOH (EVAL L171B from EVAL Europe NV with an ethylene content of 20µm 27 mol%) Inner layer 50% PE-HD, 50% PE-LLD 120µm

[0035] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 20 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 300 µm. Example 6:

[0036] A tube jacket with the following structure was produced by coextrusion: layer material thickness Outer layer 80% LLDPE, 20% LDPE 220µm barrier layer EVOH (EVAL L171B from EVAL Europe NV with an ethylene content of 27 mol%) 20µm Inner layer 50% PE-HD, 50% PE-LLD 220µm

[0037] The outer diameter of the tube jacket was 40 mm, and the jacket length was 107 mm. A 20 µm thick adhesion promoter layer (Admer NF 498E from Mitsui Chemicals Europe GmbH) was placed between the inner layer and the barrier layer, as well as between the outer layer and the barrier layer. The wall thickness was thus 500 µm.

[0038] The tube jackets manufactured according to the specifications given in Examples 2-6 were tested for their barrier properties and inherent stability. The oxygen transmission test was conducted in accordance with the following standard: DIN 53380-3 Determination of gas permeability; Part 3: Oxygen-specific carrier gas method for measurements on plastic films and plastic molded parts. The sample specimen is exposed to a test gas with a specific oxygen content at atmospheric pressure on one side (outside). On the other side (inside) of the sample specimen, which is tightly separated from the first side, the diffused oxygen is "carried along" by the carrier gas (N2) and transported to an O2 sensor. The temperature of the sample or sample chamber was set at 40°C, and the moisture content of the test gas was 0%.

[0039] The following O 2 transmission values were measured: Example Thickness of the barrier layer [µm] Wall thickness of the tube jacket [µm] Ethylene content [mol%] O2 transmission [cm3 / tube / day] 2 20 500 32 0, 0058 3 10 300 27 0, 0029 4 10 500 27 0, 0022 5 20 300 27 0,0014 6 20 500 27 0,0012

[0040] It was found that the tube jackets exhibited sufficient barrier properties. In particular, the influence of the ethylene content on the barrier properties of the barrier layer was evident. A comparison of Examples 2 and 3, for example, shows that the O2 transmission of the tube according to Example 3 is significantly lower, even though both the thickness of the barrier layer and the wall thickness of the tube jacket are greater in Example 2.

Claims

1. A tube for receiving a liquid or pasty product comprising a multilayered tube jacket, the tube jacket having one or more outer layer(s) made of polyolefin, one or more inner layer(s) made of polyolefin and a barrier layer arranged between the outer layer(s) and the inner layer(s), wherein the barrier layer consists of an ethylene-vinyl alcohol copolymer (EVOH), characterized in that the ethylene-vinyl alcohol copolymer of the barrier layer has an ethylene content of <28 mol% and the thickness of the barrier layer is ≤ 25 µm.

2. The tube according to claim 1, characterized in that the thickness of the barrier layer is between 5 and 25 µm.

3. The tube according to claim 1 or 2, characterized in that a bonding layer is arranged on both sides of the barrier layer in direct contact with the same.

4. The tube according to claim 1, 2 or 3, characterized in that the thickness of the bonding layer is 5-25 µm, preferably 10-20 µm.

5. The tube according to any one of claims 1 to 4, characterized in that the one or more outer layer(s) has or have a total thickness of 80-300 µm.

6. The tube according to any one of claims 1 to 5, characterized in that the one or more inner layer(s) has or have a total thickness of 80-300 µm.

7. The tube according to any one of claims 1 to 6, characterized in that the tube jacket has a total thickness of 200-600 µm.

8. The tube according any one of claims 1 to 7, characterized in that the total thickness of the one or more outer layer(s) is 30-70% of the total thickness of the tube jacket.

9. The tube according to any one of claims 1 to 8, characterized in that the total thickness of the one or more inner layer(s) is 30-70% of the total thickness of the tube jacket.

10. The tube according to any one of claims 1 to 9, characterized in that the tube jacket is produced by coextrusion.

11. The tube according to any one of claims 1 to 10, characterized in that the one or more outer layer(s) consist(s) of polyethylene (PE).

12. The tube according to any one of claims 1 to 11, characterized in that the one or more inner layer(s) consist(s) of polyethylene (PE).

13. The tube according to claim 12, characterized in that the polyethylene of the one or more outer layer(s) and / or of the one or more inner layer(s) has a proportion of at least 20% by weight of high-density polyethylene (PE-HD) with a specific weight between 0.935 and 0.97 g / cm3.

14. The tube according to any one of claims 1 to 13, characterized in that the tube jacket has an outer diameter of 13-60 mm, preferably 25-50 mm.