FI100784B - Process for preparing a multilayer carton profile - Google Patents

Description

100784

METHOD OF MANUFACTURING A MULTILAYER BOARD PROFILE

The invention relates to a method for producing a multilayer cardboard profile, in which method adhesive-coated cardboard webs are pressed together and produced into a desired profile.

A method for producing a multilayer board profile is already known from patent publication FI 782788 (Interleasing Ky), in which method thermoplastic coated board webs are heated by passing the webs through a flame field and pressed together and profiled to the desired profile. Since then, the method has been further developed with the said company Interleasing Ky and with other companies that have cooperated with them; reference is made to 15 patent publication FR 2660893.

In the above-mentioned methods, the raw material used is mainly cardboard tape coated with thermoplastic. However, the availability of cardboard tape coated with thermoplastic, such as polyethylene, has significantly improved recently, and at the same time its market price has risen. Thus, in recent times, efforts have been made to find new raw materials for the production of board profile, the need for which is constantly growing on the market, for example in the case of vegetable packaging.

25 For this purpose, an attempt has been made to use, as a raw material, * ... · waste paperboard which is not coated with thermoplastic and which thus has to be glued to a multi-layer board profile. However, the gluing process is quite cumbersome, and the handling of aqueous adhesives in particular is problematic. In particular, the gluing of the paperboard webs with an aqueous adhesive causes the board profile to get wet, which requires a very cumbersome drying step due to the difficult drying of the multi-ply board profile. In particular: It is very difficult to dry cardboard profiles with an aluminum foil film or some other film which prevents moisture evaporation.

2 100784

It is an object of the present invention to obviate the above drawbacks.

In particular, it is an object of the invention to provide a new method for producing a multilayer paperboard profile from paperboard webs by gluing so that the drying of the profiles can be carried out efficiently and quickly without special additional measures.

For aspects of the invention, reference is made to the claims.

The invention is based on extensive research prior to the invention, in which it was surprisingly found that when using an aqueous adhesive, excess and harmful moisture can be removed immediately after application of the adhesive by flame heating, after which the webs can be compressed into a uniform board profile in a conventional manner.

The size of the adhesive used is preferably such that it forms a heat-sealable film on the surface of the paperboard web during drying.

The adhesive may be, for example, a latex adhesive containing thermoplastic. Any latex adhesive containing thermoplastics known per se is possible, polyvinyl alcohol-based, polyvinyl acetate-based or, in general, any aqueous thermoplastic film-forming adhesives being particularly preferred.

The glue is applied to the surface of the cardboard web • · ·. · '' E.g. 20 to 80 g / m 2, preferably of the order of 50 g / m 2 ± 20 g / m 2. Moisture is removed from the adhesive in such a way that an adhesive of the order of 5 to 15 g / m 2, preferably 5 to 10 g / m 2, remains on the surface of the web. The adhesive remaining on the surface of the web is preferably mainly a specific adhesive, such as polyvinyl alcohol.

: .I. The adhesive is preferably applied to the surface of the web in excess • · · and the excess is removed. The excess can be removed in a manner known per se, e.g. by means of a mechanical stencil, by means of an air stencil, by deriving Ί *. the web through the press nip or by another method well known in the art, e.g., paper 3 100784. The removal of moisture from the web is carried out by flame heating, i.e. the web is passed past a flame heater directed towards the web. In practice, the adhesive Levi-5 is applied to the surface of several cardboard webs, e.g. 3-10-20 or more, simultaneously and the cardboard webs are passed immediately after the application of the adhesive through a flame field so that the excess moisture can be evaporated. Flame heating is preferably provided by any combustible gas burning bulbs, e.g. natural gas or liquefied petroleum gas bulbs, as is known in the art.

If desired, the formed cardboard profile is coated with a paper strip which is turned over the edges of the profile-15. If desired, e.g. two paper strips can be used, the wider of which is placed on the other side of the profile and turned over the edges of the profile against the opposite side of the profile and the narrower strip is placed against the opposite side of the profile on the edges of the wider strip. If desired, the profile can also be coated with one wide paper strip, which is turned around the entire profile and glued against the surfaces of the profiles, the edges of the strip on top of each other.

:: '· 25 When coating a board profile with one or more paper strips, on the surface of the paper strips • · ·. . ·, The coating can be applied in the same way as described above when applying the adhesive to the surface of the cardboard webs, i.e. the adhesives described above can be used as the adhesive, and the adhesive can be dried by the method described above. Likewise, an excess of glue can be used and the excess removed by the methods described above. Of course, the paper tape can be applied to the surface of the cardboard profile by any method and method known per se, e.g. using a paper tape coated with a thermoplastic or generally with a suitable adhesive surface, as is known in the art.

The board profile produced using the method according to the invention is dry without special drying operations. The consumption of glue is excellent 5, and the glue is very inexpensive. Thus, the economics of using the method are very advantageous. The apparatus for implementing the method is simple in structure and does not require the use of costly electric heaters or otherwise complex and expensive constructions. The hardware is simple, easy to manage and use.

Thanks to the invention, any cardboard raw material can be used for the manufacture of corner guards, i. the method does not require the use of a thermoplastic coating-15 t.

The method has been described above for general use in the production of plywood profiles. This refers mainly to V-shaped or other shaped corner guards, laminated cores for use as winding cores, generally cardboard laminated profile products such as corrugated cardboard, planar armor cardboard, furniture frames, shell and parts thereof, and parts thereof. parts, etc. In general, the basis weight of such products is: · 25 orders of magnitude greater than 100 g / m2, e.g. 200 g / m2, 300 g / m2 or even many times heavier.

t · ·. The invention will now be described in detail, by way of example, with reference to an exemplary embodiment, with reference to the accompanying drawing, which shows the method according to the invention as a practical application seen from the side.

In this experiment, an adhesive was prepared by dissolving polyvinyl alcohol in about 10% by weight of water at a temperature. mp 95 ° C. The adhesive was applied to the cardboard webs 1 shown in the figure using a roller application, i.e.

• · 35 roll moistened with glue 2 pressed the glue board strips ·. against. Immediately after roller application, the excess glue was removed with a mechanical scraper blade 3 100784 5. Glue was then left on the surface of the cardboard web.

50 g / m2. Thereafter, the paperboard webs 1, 8 in total, were passed through a flame field 4, where the webs were strongly heated in a flame field formed by introducing liquefied gas into the combustion nozzles, in the figure the nozzles and gas pipes are covered behind the flames. Thus, the drying took place immediately after the application of the adhesive, and the adhesive did not have time to be absorbed on the surface of the Tainos. The running speed of the webs was of the order of 10 30 - 100 m / min, the length of the flame field was of the order of n.

lm, i.e. the drying step lasted 0.7 - 2 s; the drying step in question is preferably less than 5 s in length, e.g. of the order of 1-2-3-4s.

After the drying step, the webs were fed to a nip 7 formed by two profiling chambers 6 and then to a second nip 8 formed by rollers 6. Finally, the formed V-shaped corner protection profile 9 was cooled by cold air blowing 10, and the profiles were cut to the desired length.

The figure also shows a coating member 11 for turning the paper strip 12 over the edges of the corner guard and a pressing device 13 for gluing the second paper strip 14 '1 /' over the edges of the previous paper strip.

The paper strips 1 are fed to the adhesive rolls 2 from the screen rollers 15 supported by the guide rollers 16. After the flame field 4, the strips are further guided by guide rollers

Ml. .1 17 supported by a nip 18 formed by the pressing rolls 5, where the strips are pressed into a single, multilayer cardboard strip.

30 Cardboard tape is coated e.g.

using a wider paper strip 12 which is pivoted over the edges of the paperboard strip by means of a guide device or a top-M, lyste member 11, as is known in the art. The second cover strip 14 is, for example, narrower than the previous one, suitably »· mainly the width of the cardboard strip, and it covers. the edges of the previous strip of cardboard. Puristuslaittees-

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sa 13, consists of, for example, two pressure rollers pressed against each other, the multilayer paperboard strip and the coating paper strips are pressed into a single, compact strip laminate.

The flame field 4 is formed, for example, by a plurality of flue gas nozzles 5, from which flames are directed between the cardboard webs 1.

The applications of the different steps of the method according to the invention and the different parts of the equipment used in the method may vary, as is generally known in the art, e.g. from the references referred to in the preamble and other patents.

The exemplary embodiment is intended to illustrate the invention without limiting it in any way. 1 · ·

Claims (12)

A process for producing a plurality of layered cardboard profile, in which the process of adhesive coated cardboard webs (1) is compressed (16, 6X) and produced to the desired profile, characterized in that aqueous adhesive (2) is spread on one surface of the cardboard webs, immediately after the application of the adhesive, the majority of the moisture is removed by flame heating (4) and the webs are compressed. 2. A method according to claim 1, characterized in that the adhesive used forms a thermally weldable film on the surface of the cardboard web in connection with the drying. 15 3. A method according to claim 1 or 2, characterized in that the adhesive is a latex adhesive and contains thermoplastic. 4. A process according to any one of claims 1 to 3, characterized in that the adhesive is 20 glue based on polyvinyl alcohol. A method according to any of claims 1 -. 4, characterized in that 20 - 80 g / m2 glue is spread on the surface of the cardboard web. I I I I !! 6. A process according to any of claims 1 to 5, characterized in that the moisture is removed from the adhesive such that the surface of the web remains 5 - 15 g / m2, preferably 5-10 g / m2 of glue. . • · · V A method according to any of claims 1 to 6, characterized in that excess glue 30 is spread on the surface of the web and the excess is removed (3). 8. A method according to claim 7, characterized in that the excess adhesive is removed with a scraper (3), an air scraper knife and / or by «« «· ... * guiding the web through a press nip. . . ·. 35 Method according to any of claims 1 -. *. : 7, characterized in that the board profile »f I · · 100784 is coated with a paper tape (12), which is folded over the edges of the profile and glued to the profile. 10. A method according to claim 9, characterized in that the cardboard profile is coated with two (12, 14) paper strips, the wider (12) of which is glued on one side of the profile and folded over the edges of the profile towards the opposite side of the profile and the the narrower web (14) is glued on the opposite side of said profile and on the edges of the wider band. 10 11. A method according to any of claims 1 to 10, characterized in that the profile is coated with a wide strip of paper, which is folded around the entire profile and glued to the surfaces of the profile. 12. A method according to any of claims 8 to 15, characterized in that adhesive according to any of the processes according to claims 1 to 7 is spread on. • • • • • • • • • • • • • • • • • tt «· *