DE2722621A1 - FLEXIBLE BAG - Google Patents

Description

HOFFMANN · EITLE & PARTNER

DR. ING. E. HOFFMANN (1930-1976) Dl PL-I NG. W. E ITLE · D K. RER. NAT. K. HOFFMANN · D I PL.-1 N G. W. LE H N

DIPL.-ING. K. FDCHSLE DR. RER. NAT. B. HANSEN ARABELLASTRASSE 4 (STERN HAUS) · D-8000 MO NCH EN 81 ■ TELEFON (089) 911087 · TELEX 05-29619 (PATHE)

29 322/4 o / wa

1. BRITISH-AMERICAN TOBACCO COMPANY LIMITED LONDON / UK

2. MARDON FLEXIBLE PACKAGING LIMITED, MIDSOMER NORTH, BATH, SOMERSET / UK

Addition to P 19 49 723.5

Flexible pouch

The invention relates to an improvement of a flexible bag or a bag, hereinafter referred to as a bag, and relates in particular to an improvement of the described and claimed in patent application P 19 49 723.5 Bag.

The patent application P 19 49 723.5 relates to a flexible bag made of a hot-sealable bag on both sides with a coating thermoplastic plastic provided with metal foil, whereby the plastics are limited to each other

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Have compatibility, and have different melting points and wherein the pouch can be reopened along a or a plurality of sealing seams between the two different coatings made of the plastics is sealed.

The present invention relates to an improvement or modification which provides further advantages and others Ways of better application and in some cases a reduction in cost is achieved.

The invention relates to a further embodiment of the patent application P 19 49 723.5 described flexible bag and is characterized in that two layers of one heat-sealable thermoplastic material on the opposite surfaces of an intermediate layer which no metal foil and other than the respective surfaces is in contact, the material of said two layers has different melting points and has limited compatibility with one another, and wherein the bag for Reopening along one or more sealing seams between the two different layers of the plastics mentioned is sealed.

The selection of the intermediate layer depends on the requirements imposed by the contents of the pouch and the intended use Intended use are given. Factors to be considered in this context, regardless of the cost are the required separation properties with regard to moisture and in some cases also with regard to the Light as well as the heat conditions required

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Strength and hardness or flexibility of the bag, the compromise that is given on the one hand by the fact that one for better recognition of the contents or of a printed matter contained within the bag, a transparency wishes and on the other hand, to protect the contents from adverse effects of light, an opacity is desired. Considering For these and other factors, the following options are available:

A pouch can be made from a laminate consisting of two layers of thermoplastic material, those with the opposite surfaces of an intermediate layer or "core" of a non-metallic Materials are connected. This intermediate layer can be transparent, for example in the form of a film a transparent cellulose or plastic material, which, as will be described below, coated or uncoated can be.

Use can be made of an opaque intermediate layer, for example one metallized in a vacuum and / or in otherwise opaque coated or uncoated film of cellulose or a plastic material.

One can have an intermediate layer of paper or cardboard that coated or not coated and / or metallized in a vacuum.

The two layers of thermoplastic material can be used without an intermediate layer other than that for attachment glue required with each other.

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One of the two layers can be metallized on one side.

An intermediate layer may be present which is suitable to advantageously maintain the desired humidity conditions to allow inside the bag, for example a layer of prepared paper or plastic material coated with a salt capable of maintaining an equilibrium moisture content of in particular tobacco within a narrow range, such as that used to protect the contents of the pouch, in particular to achieve optimal smoking properties, is necessary to maintain. In all cases you can the outer layers of thermoplastic materials with limited compatibility polyolefins with different melting points be, the difference in melting points in the range of 5 to 50 C is appropriate in the case of polyethylene materials be used. The material which forms the outside of the bag preferably has the higher melting point .

The composition and the type of manufacture of the bag can be carried out in the manner described in DT-OS 1,949,723.

The invention is described in more detail in the following examples.

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example 1

Transgarente "intermediate layer

(a) To make a transparent flexible bag, a sheet material with a three-layer structure is made, in which a transparent intermediate layer consists of a cellulose film with 44.5 g / m of a polyvinyl idene chloride copolymer was coated (available

at British Cellophane Limited as 445 MXXT / A Cellophan), 2

those with 2 g / m of adhesive based on polyurethane was laminated with polyethylene films both of which were 50 µm thick and one of which had a melting range of 100 to 150 ° C and the other has a melting range of 105 to 125 ° C had and where the material that formed the outside of the bag, the higher melting point compared to the the inner layer. The coating on both

Two sides of the intermediate layer consisted of 1.5 to 2.5 g / m 2 of a copolymer of vinylidene chloride / acrylonitrile / acrylate.

A bag was produced from this material in the manner described in DT-OS 1,949,723. The so educated The bag had a seal that could be torn despite the hermetic seal.

Such a bag has effective protective and separating properties on, but it allows the content to be seen clearly. Due to the flexibility of the pouch, the The risk of destruction during storage and transport is reduced and the bag has a good appearance and a comfortable grip. Deformations and the loss

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good looks when the contents are packed under reduced pressure can thus be avoided. Besides that a reduction in costs is achieved.

(b) Another transparent interlayer was used

used, which consisted of a 32.5 g / m uncoated cellulose film, which was available from British Cellophane Limited as 325 P cellophane is sold.

(c) Another transparent interlayer made of an oriented polypropylene was used, which is interleaved with a 80 µm thick polyvinylidene chloride copolymer and manufactured by I.C.I. Limited under the trade name Prapofilm "C" is distributed.

(d) Finally, another transparent intermediate layer of 20 µm nylon 6 film was used.

The materials (b; to (d) gave similar properties like that of (a), but (b) showed, in addition to the transparency, a lower permeability, while (d) an additional one Toughness revealed.

Example 2

(a) A sheet material consisting of

a cellulose film made with 36.5 g / m polyvinylidene chloride copolymer was coated and that of the British

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Cellophane Limited is sold as 365 MXXT / A Cellophane and on this material was metallic aluminum on both sides has been metallized in a vacuum with a thickness corresponding to an optical density (reverse logarhythm the light transmission) from 2.5 to 4, with the metallized film forming an intermediate layer in a laminate from two polyethylene films of different melting ranges, as described in Example 1 (a).

The aluminum can also be applied to only one side of the film.

(b) An alternative intermediate layer consisted of a cellulose film with 44.5 g / m 2 of a white opaque Polyvinylidene chloride copolymer and sold by British Cellophane Limited as 445 MXXB / A will.

(c) Another intermediate layer was made from a 12 µm thick film of polyethylene terephthalate, that was metallized on one side up to an optical density of 3.5 to 4.0.

In addition to the advantages in terms of release properties, appearance and the other properties listed under 1 (a), a metallic or other opaque appearance can be achieved at low cost. In particular the intermediate layer according to 2 (b) can also be printed.

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Example 3

(a) Make an opaque sheet material that

from an intermediate layer of a 100 g / m clay coated Paper (clan label from Inveresk Paper Company Limited) consists of two different polyethylene films Melting range, as previously described, laminated was.

(b) The intermediate layer consisted of 52 g / m plastic paper, as supplied by DuPont under the trade name Tyvek.

In addition to the opacity, such an intermediate layer causes rigidity or hardness

and good properties against mechanical destruction combined with low cost. A particularly attractive one Appearance is achieved with 3 (b).

Example 4

A sheet material is produced from two adjacent Layers of polyethylene film of different melting * range, as described above, exist, of which the one, in this case the outer layer with the higher melting temperature, only on the inner surface with aluminum was vacuum metallized to an optical density

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from 3 to 4. Such a layer gives good release properties and a pleasant appearance. Each of the two layers can be metallized and printed.

For some purposes one can do without metallization, whereby the two layers of polyethylene materials are laminated together but without another integrating intermediate layer. The polyethylene material can be as per 1 (a) be described. A bag formed from this sheet material has good flexibility at a low cost. In particular when producing this laminate, the components can be wound unlaminated onto a spool and can then be sealed together at the corners and / or laminated if desired. That way you can save further costs.

Example 5

Moisture control layer

(a) An intermediate layer is made from an absorbent paper that has been treated with a saturated solution of Sodium chloride was impregnated to maintain moisture in the pouch so that it kept it inside Tobacco had a moisture content of essentially 12.5% during the period of storage prior to sale and consumption. The other layers consisted of polyethylene films as described under 1 (a). The permeability the inner layer, i.e. the layer facing the contents of the bag or packaging

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be such that an exchange of water vapor between the contents and the salt is possible. The outer layer, i.e. the layer between the salt and the atmosphere should be substantially less permeable than the inner one Layer. The permeability can be adjusted, for example, by changing the thickness of these layers.

The relative humidity maintained is determined by the The particular salt used is determined, but it varies with the ambient temperature and the salt needs to be taken into account this fact can be selected. The amounts of salt and water in the paper determine the duration of the Protection but this protection also changes with the relative humidity of the environment and the permeability of polyethylene. The salt releases or absorbs moisture, depending on the vapor pressure of the environment.

(b) A bag measuring 157 mm 127 mm with a closure flap of 157 mm 85 mm is made of three layers. The outer layer of the bag is formed from 150 mm thick polyethylene having a water vapor transmission rate (MVTR) of 2.5 g / m ^2/24 h at 38 ° C, 90% relative humidity (RH). The central layer

consists of 80 g / m 2 adsorbing paper measuring 150 χ 335 mm, which was impregnated with 1.1 g of dry sodium chloride. In addition, the paper layer contained 1.5 ml of water. The inner layer was formed from a copolymer of vinyl acetate (12%) and ethylene (88%) with an MVTR of 50 g / m ^2/24 h at 38 ° C and 90% RH. The central layer is completely surrounded at all corners by the plastic layers and can be laminated on their inner sides

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be. This system maintains a relative humidity of 75.1% in the pouch at 25 ° C, with a degree of relative humidity change with respect to temperature equal to 0.02 RH per ⁰ C change in temperature.

If the bag is used to hold 50 g of pipe tobacco with a moisture content of 20%, then is the relative humidity to maintain this moisture content 75%. Such a bag would be hermetically sealed and the seal at the open end could be torn due to the different sealing properties of the dissimilar plastic layers.

When stored, such a pouch will keep the moisture content of the tobacco at 20% for various periods of time, depending according to the actual storage conditions. For example, at 35% relative humidity at 38 ° C, the humidity level of 20% is maintained over a period of 5 weeks before the tobacco is released at a rate determined by the M.V.T.R. the outer plastic layers is caused Losing moisture. At 90% relative humidity and at 38 ° C, the level of 20% humidity could approximate To be maintained for 13 weeks before the tobacco begins to absorb moisture, which is determined by the degree of moisture Unsaturation of the enclosed, a salt solution containing paper layer is caused. Regarding the execution of the bag, reference is made to FIGS. 1 to 8 of DT-OS 1 949 723, the intermediate layer 2 according to the present invention is executed.

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In the drawing, A represents one outer layer and C the other outer layer. The to be used according to the invention Interlayer is denoted by B.

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Claims (12)

HOFFMAIVÜV · EITLE & PARTNER PATENTANWÄLTE DR. ING. E. HOFFMANN (1930-1976) ■ D I PL-I N G. W. E ITLE · D R. RER. NAT. K. H OFFMAN N · D I PL.-I NG. W. LEH N DIPL.-ING. K. FOCHSLE DR. RER. NAT. B. HANSEN ARABELLASTRASSE 4 (STERNHAUS) · D-8000 MO N CH EN 81 · TELEPHONE (089) »11087 · TELEX 05-29619 (PATH E) 29 322/4 o / wa 1. BRITISH-AMERICAN TOBACCO COMPANY LIMITED LONDON / UK 2. MARDON FLEXIBLE PACKAGING LIMITED, MIDSOMER NORTH, BATH, SOMERSET / UK Addition to P 19 49 723.5 Flexible pouch PATENT CLAIMS Flexible pouch made of two layers of heat-sealable thermoplastics, the plastics of the two layers having different melting points and limited compatibility with each other and the pouch for reopening along one or more sealing seams between the surfaces of the different layers of the plastics mentioned is sealed according to the patent application P 19 49 723.5, thereby 709849/0896 ORIGINAL INSPECTH) characterized in that the two plastic layers abut on the opposite sides of an intermediate layer , this intermediate layer not being a metal foil and having different surfaces than the adjacent plastic layers. 2. Bag according to claim 1, characterized in that that the two layers are made of polyolefin materials, preferably polyethylene materials. 3. Bag according to claims 1 or 2, characterized in that the intermediate layer consists of a transparent material. 4. Bag according to claim 3, characterized in that the intermediate layer consists of a film of a transparent, coated or uncoated cellulose or plastic material. 5. A bag according to claim 4, characterized in that the material of the intermediate layer is coated with a copolymer and, for example, coated in a layer of oriented polypropylene: with a polyvinylidene chloride copolymer consists. 6. Bag according to claim 4, characterized in that the intermediate layer is made of a nylon-6 film. 7. Bag according to claims 1 to 6, characterized in that the intermediate layer is an opaque Material is. 709849/0896 "■ 3 ~ 8. Bag according to claim 7, characterized in that the intermediate layer consists of a material in which a metal has been applied in a vacuum to one or both surfaces. 9. Bag according to claims 7 or 8, characterized in that the material is a coated Cellulosic material is. 10. Bag according to claims 7 or 8, characterized in that the intermediate layer made of paper or cardboard. 11. Bag according to claims 1 to 10, characterized in that said two layers adhere to one another and one is vacuum metallized on one side. 12. Bag according to claims 1 to 11, characterized in that the intermediate layer is a prepared paper or plastic material, which with a Salt is loaded and which is capable of the moisture conditions of the contents of the sachet within predetermined limits as required to protect the content. 709849/0896