CA1176149A - Method for the manufacture of multilayered complexes - Google Patents

Abstract

The invention relates to the preparation of a multilayer complex comprising an aluminum film integral with at least one layer of polymer. According to the invention, the surface of the aluminum film in contact with the polymer layer is subjected to a treatment with water brought to a temperature above 60.degree.C. The complex granted is suitable for the manufacture of capsules or lids.

Description

~ 76 ~ 9 , , Method for manufacturing multi-layer comDlexes.
The present invention relates to a manufacturing process tion of multilayer complexes ~ intended in particular for packaging ~ closure ~ plastic ~ as ~ by example, bottles.
In this definition of ~ in ~ ention ~ we mean by multi-layered complex a complex ~ e composed of less ~ two layers .
It is known to use ~ currently ~ to close 10 hollow body made for example of plastic material ~
or any other packaging, capsules or covers round or any shape, cut from ~ sheets ~
multi-layer ~ composed of a film of aluminum and less a layer of plastic material ~ which seal off in a manner ~
15 seals said packages. General plastics Lely used to form these bou ¢ ha ~ e capsules ~ have polyethylene ~ polypropylene ~ polychloride do vinylo or polystyrene, or combinations of these res ~ l ~ sealing of packaging by said capsule ost 20 obtained by adhesion of the multilayer complex and do the ~ e ~ -heat sealing.
Depending on the ~ plastics ~ ticks ~ used ~ the leaves multilayer ~ have a layer of glue between the aluminum ilm and the plastic layer.
It ~ can also be constituted ~ as described in the French patent ~ n 1,594,448 ~ of which theESSessesso is tibular ~ by an aluminum film and a layer of polyethylene containing, grafted ~ a non-carboxylic acid ~ aturated, such as acrylic acid.
Using capsules made from such complexes multilayer, thermo-celled on the 8 packages in the adequate conditions ~ we generally get a fermeturo waterproof ~ indi ~ thinkable for the good conservation of the product packaged in packaging.
3 ~ However, it may happen that the films separate accidentally from each other and a closure ~ tench no ~ no longer obtained ~ which naturally harms good con ~ ervation of the packaged product '' . .

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: 1 ~ 76 ~ 9 ,. ~

- 2 -This name ~ ne is called delamination and the cauaea e ~
are poorly known.
The plaintiff nonetheless found a way to overcome this disadvantage by applying to the aluminiu sheet ~
S traling with water brought to a temperature 8U ~ -less than around 600C.
It further established that the adhesion of the polym ~ re our aluminum film was improved by this treatment.
Of more ~ it ar ~ ussi to adhere to the aluminum film nium a layer of a particular polymer, without using ~ tlon glue ~ which could not have been achieved ~ uaqu'à pr ~ sent-An object of the present invention is therefore to improve the adhesion of a polymer layer to an aluminum film.
and dtéviter ain ~ l delamination of complex ~ multlcoucho ~.
Another object of the invention is to obtain adhesion direct from a layer of polymer ~ on an aluminum film ~
~ an ~ interpoaition of an auxiliary agent.
To this end ~ the invention has ob ~ and a method of pre-20 paration of a multilayer complex deatiné in particular ~ packaging lafermeturo ~ said comple ~ e comprising a film alumlnium ~ olidaire of at least one layer of a polymer, said process being characterized in that the surface of the aluminum film in contact with the polymer layer is 25 80umiae to treatment with water brought to a temperature ture above 600C. Lower water temperature or equal to 200C can be considered sufficient.
Dan ~ the method according to the invention, treatment with water can be done before the aluminum film is 30 made integral with the polymer layer.
It can also be twisted after the operation.
comple ~ e himself ~ me being alor ~ ~ oumi ~ to treatment by the water.
Water can ~ o find penny ~ liquid form or ItOU ~ form 35 of steam.
According to the invention ~ the polymer layer can be com-poaée including dtun ¢ ethylene opolymer and a ~ ide oarbo ~ ylique mono-ethylénique ~ on ~ aturé. Co polymhr-.

~ 7 ~ 9

- 3 -can be obtained in particular by polymerization of ethylene, then grafting a small amount, usually less than 5 ~ by weight, of a carbohydrate acid ~ monoethylenic yl no ~
saturated; this acid can be for example acrylic acid o ~
methacrylic.
The polymer layer can also be composed of high density polyethylene.
It can also be composed of a mixture of polymer ~ such as, for example, a copolymer of ethylene and acrylic acid, as defined below ~ uA ~ we mix ge with a copolymer of ethylene and acetate vinyl.
The aluminum film may have a thickness preferably between 30 and 80 microns.
S The same applies to the thickness of the poly-m ~ re when the polymer is for example polyethylene or a copolymer of ethylene and a carbo acid ~ yliquo unsaturated monoethylenic ~, as described above, or high density polyethylene.
According to the invention, the complex is prepared, after ~ s é ~ entement treatment of the aluminum film with ~ au t brought to a temperature above 600C, pui ~ solida ~
the aluminum film and the polymer layer ~ by pa ~ wise film and layer, in a manner known per se ~
on ~ heated transfer rollers.
Water treatment can be performed apra ~ I
pa ~ a ~ e on the transfer rollers.
The method according to the invention can also be used.
~ é for the manufacture of complexo ~ bilayers or tricouphoc particular ~ including:
- aluminum film, - a thin layer (from 1 to 10 microns approximately) dlu ~
copolymer of ethylene and acrylic acid, such as defined above, ~ eul or mixed with an oopol ~ m ~ r-;
propylene and acrylic acid;
- é ~ entuellemont a layer of polyethylene or d-polypropylene.

76 ~ 9

- 4 -In this case, the complex is prepared ~ pre ~ erected by - a particular process comprising the following steps:
a) the preparation of a suspension of the copolymer, alone or mixed in an organic liquid, S b) coating of the metallic film with the suspension copolymer, c) elimination of the organic liquid, d) melting the copolymer, so as to obtain a continuous layer of the copolymer on the metallic film.
The suspension of the copolymer can be obtained e ~
dissolving the copolymer alone or as a mixture in a organic liquid, then cooling the solution ~ said cooling preferably being rapid.
The enductiop of the aluminum film can be made by S of ~ means known in the art. It can be done tuo ~ by e ~ ample, using a tran ~ fert roller.
The organic liquid contained in the suspension must en ~ uite be removed from the coated metal sheet, by ~ drying of the support, for example by chau ~ fage dan ~ a tunno heating, The aluminum silm is then brought to a temperature.
sufri ~ ante so that the ~ compound ~ 60ient melted ~.
Dan ~ lo ca ~ where o ~ DéJire get a complexo trlco ~ ch-~ we can ~ attach a pe layer to the polymer coucho polyethylene or polypropylene by passing over ro ~ _ the transfers.
In the case of the preparation of these bi-or tri-layers t the treatment with water is done a ~ ant or after solidari ~ ation of the layer ~.
The process according to ~ in ~ ention provides back comple ~ es ~ which delaminate only very difficult. In indeed, the complexes ~ prepared in a conventional manner, key ~ t- ~ say without the aluminum film ~ oit treated by do hot water a ~ ant their use, come to ~ e delaminate.
3S C ~ is the case, in particular, ~ when, after thermo6cellage Jur le ~ containers ~ are cooled by cold water ~ doO
The examples that follow are intended for ~ tror ``
.., ', :
-, 1 ~ 7 ~ 9 in ~ ention. They are not limiting.
EXE ~ PLE 1 This e ~ example relates to trial4 delamination carried out8 by a bilayer complex composed of an aluminum film of thickness of 50 microns and a film of copolymer ~ e of ethylene and acrylic acid 50 microns thick also.
This copolymer was obtained by grafting on polyethylene high density lene (d = o, 960) of acrylic acid (1 ~ in weight approximately).
We calender at 220C, between two cylinders, the film aluminum and the copolymer film.
Preparing from the complex thus obtained 10 mm wide samples, T and A.
S The samples T, which are samples ~ t ~ monk, do not have special treatment.
The samples A are brought into contact with ~ ec do steam at 120C for 20 min.
The samples T and A are then dipped in water at 23C-We then follow the variation of the adhesion of Y film ~ I
of alumin ~ um and of copolymer as a function of the time of tr ~ m- ¦
page in water at 23C. The adhesion tests are of the type ~ poeling ~ and consist of measuring the adhesion strength of 25 films of copolymer ~ re and aluminum ~ when il9 are ~ oumi ~ I
opposite tensile forces ~ the complex being main- ¦
held perpendicular to the acting forces.
We measure the "peeling" aerence / which is the force average per unit of specimen width required for cause separation of the two films when the two ~
films are ~ screened ~ at a uniform speed of 120 mm / min.
Tests were carried out over a period of four weeks.
For T samples, adhesion before soaking 3S in water at 25 ~ C is close ~ 400 gf / 10 m ~. It decreases with soaking time and reached after 5 hours approximately, a value close to 200 gf / 10 mm. For ~ chan ~
tillons A, the grip close to 800 gf / 10 mm reote co ~ otan-you.

1 ~ 7 ~; ~ gl9 This example concerns delamination tests on complexes Bl and B2 similar to the complex A of the example 1.
S Bl and B2 complexes are soaked in eRu brought to different temperatures: 80C and 100C.
The soaking time was varied by 15 minutes3 ~ 2 hours 45 minutes. We then have, in the same way that q ~ e dan ~ Example 1, performed ~ adhesion tests in the com ~
against the tests carried out with the control complexes T.
For B1 complexes (treated in water at 80C), adhesion, after 24 hours of soaking in water 23C, increases with treatment time in water at 80C. It goes about 250 gf / 10 mm for 1/4 hour S treatment at 500 gf / 10 mm for 2 3/4 hours.
For B2 complexes (treated in water at 100C), adhesion, after 24 hours of soaking in water ~ 23-C, increases with treatment time in water at 100C.
It goes from around 500 gf / 10 mm for 1/4 hour do 20 tra $ te0ent at 800 g ~ / 10 mm for 2 3/4 hours.
For T samples, adhesion after 24 hours ~ do soaking in water at 23C ~ is 200 gf / lO mm on ~ iron.
Lladhérenco of ~ complexes prepared by the process ~ die ~ elo ~
lnventlon e ~ t therefore much better.

This example concerns delamination ~ ur ~ eo complexes C similar to those of examples 1 and 2.
However, these complexes C are prepared apartlr ~ 'a aluminum film previously treated with water ~ 1 ~ 0C.
The soaking time was varied from 15 seconds to ~ 0 minutes. ~ then did the two-layer complexes ~ ¦
in the same way as in Example 1, and performs ~ des ~ est ~
identical adhesion in comparison ~ nt to tests ~ effec ~ és with the control complexes T., Adhesion ~ after 24 hours soaking in water ~ a 23C, increases with the pretreatment time of ~
aluminum in water at 100C. After 30 seconds ~ do '::
'' 1 ~ 7 ~ 9 _ 7 _ treatment, it is around 300 gf / 10 mm; after ~ 2 minutes ~
-it is about 500 gf / mm and, after 10 minutes, it is greater than 800 gf / 10 mm.
For T samples, adhesion after 24 hours ~ d

5 soaking in water at 23C is about 200gf / 10mm.
The adhesion of deo complexes prepared by the process ~ elou the intention is therefore much better.

This example concerns delamination tests carried out ~
on a bilayer complex D composed of an aluminum film ~ m with a thickness of 50 microns and a film of ~ thickness of 50 microns of high density polyethylene (d = o, 960) ~ of molecular weights by weight Mw = 110,000 and by number Mn =
13,000.
15We tried to adhere the aluminum films ot high density polyethylene, ~ year ~ pretreatment of the aluminlum by water, by calendering at 220C. The ~ fi ~ ms do not adhere.
We then realize the complex D of the same ~ açon, ~ ai-after treatment of the aluminum film for 20 minutes in water at 100C. We perform on the complexo D a te ~ t of peeling as described above ~ demment.
We obtain a speed of 100 gr / 10 mm. ~ near soaking ~ go of the dano complex of water at 23C for 24 hours ~, we Z5 achieves the same result.
The method according to the invention therefore makes it possible to make directly adhere a high density polyethylene film on aluminum foil ~ which is impossiblo automroment.
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Claims (14)

THE ACHIEVEMENTS OF THE INVENTION ABOUT WHICH A RIGHT
EXCLUSIVE OF OWNERSHIP OR PRIVILEGE IS CLAIMED, ARE
DEFINE AS FOLLOWS 1. Process for the preparation of a multilayer complex intended in particular for closing packaging, said complex comprising an aluminum film secured to at least one polymer layer, said process being characterized in that the surface of the aluminum film in contact with the layer of polymer is subjected to treatment with worn water at a temperature above 60 ° C. 2. Method according to claim 1 characterized in what the water temperature is less than or equal to 200 ° C. 3. Method according to claim 1, characterized in what the water is in the liquid phase. 4. Method according to one of claims 1 and 2, characterized in that the water is in the vapor phase. 5. Method according to claim 1, characterized in what the water treatment is done before the film of aluminum is made integral with the polymer layer. 6. Method according to one of claims 1 to 3, characterized in that the water treatment is carried out after the aluminum film has been made integral with the polymer layer. 7. Method according to claim 1, characterized in that the polymer is a copolymer of ethylene and an unsaturated monoethylenic carboxylic acid. 8. Method according to claim 7, characterized in what the unsaturated nonoethylenic carboxylic acid is acrylic acid. 9. Method according to claim 5, characterized in that the polymer layer is made of polyethylene high density. 10. Method according to one of claims 7 to 9, characterized in that the complex is composed of a film aluminum with a thickness between 30 and 80 microns and in that the polymer layer has a thickness comprised between 30 and 80 microns. 11. Method according to claim 1, characterized in that the polymer layer consists of a mixture of polymers. 12. Method according to claim 11, characterized in what the polymer blend is made up of a blend of a copolymer of ethylene and acrylic acid and of a copolymer of ethylene and vinyl acetate. 13. Method according to one of claims 7 and 8, characterized in that the complex is prepared by a process comprising the following stages: a) the preparation of a suspension of the copolymer, alone or as a mixture, in a liquid organic, b) coating the metallic film with the suspension of the copolymer, c) elimination of the organic liquid, d) the melting of the copolymer, so as to obtain a continuous layer of the copolymer on the metallic film, e) an optional step additional consisting of joining to the layer of copoly-mother a layer of polyethylene or polypropylene. 14. The complexes prepared by a process according to one of claims 1 to 3.