WE CLAIM:
1.- Binding folder for binding a bundle of leaves (2), whereby this binding folder (1) comprises a continuous cover (3) with a spine (5) and two endpapers (6), whereby in the spine (5) a U-shaped profile (4) from heat-conductive material is applied, with the U-shaped profile (4) comprising a base (7) and upright arms (8) and whereby in the U-shaped profile (4) a binding adhesive (9) is applied in the form of a hotmelt adhesive, characterised in that the U-shaped profile (4) is applied in the spine (5) by means of an assembly adhesive (11) between the upright arms (8) of the U-shaped profile (4) and the spine (5) of the cover (3), whereby this assembly adhesive (11) extends beyond the free edges (10) of the upright arms (8) and over these free edges (10), whereby the assembly adhesive (11) is a non-reactivatable glue, such as a polyurethane glue.
2.- Binding folder according to claim 1, U-shaped profile (4) is made of a metal, e.g. steel.
3.- Binding folder according to any one of the previous
claims, characterised in that the binding adhesive (9) is
at least applied on the base (7) of the U-shaped profile
(4) .
4. - Binding folder according to any one of the previous claims, characterised in that the cover (3) is made from cardboard, plastic or laminated foil.

5.- Binding folder according to any one of the previous claims, characterised in that the cover (3) is laminated on the inside with a layer of plastic (13), such as e.g. a layer of polyvinyl chloride or polyester.
6.- Binding folder according to any one of the previous claims, characterised in that a paper layer (12) covers or is glued on the inside of the U-shaped profile (4).
7. - Binding element according to any one of the previous claims, characterised in that the U-shaped profile (4) is made in such a way that the free edges (10) of the upright arms (8) have been realised such that they can be folded toward one another.
8.- Binding element according to any one of the previous claims, characterised in that the cover (3) is glued over the whole or practically the whole outside surface of the U-shaped profile (4) on the U-shaped profile (4).
9.- Method to produce a binding folder (1) according to any one of the previous claims, characterised in that the method consists of the following steps:
- the provision of a flat continuous cover (3) consisting of a spine (5) and two endpapers (6);
- the applying of an assembly adhesive (11) on the inside of the cover (3) in the form of two or more strips (14) extending at a distance from one another and parallel or approximately parallel to each other in the spine (5) of the cover (3);

the placing of a U-shaped profile (4) of heat-conductive material in the spine (5) of the cover (3), with the U-shaped profile (4) comprising a base (7) and upright arms (8) and whereby in the U-shaped profile (4) a binding adhesive (9) in the form of a hotmelt adhesive is applied; - the folding up of the endpapers (6) of the cover (3) such that the spine (5) of the cover (3) is folded around and against the U-shaped (4) profile;
whereby the amount of assembly adhesive (11) that is applied on the inside of the cover (3) is chosen such that after folding the cover (3), the assembly adhesive (11) extends beyond the free edges (10) of the upright arms (8) and over these free edges (10).
10.- Method according to claim 9, characterised in that after the step of folding the endpapers upwards (6), the spine (5) of the cover (3) is pressed against the U-shaped profile (4) such that a good adhesion is obtained.
11.- Method according to claim 9 or 10, characterised in that the U-shaped profile (4) is produced by departing from a sheet of heat-conductive material, whereby a paper layer (12) covers or is glued, optionally, on at least one side of the sheet, whereby subsequently on this side a binding adhesive (9) in the form of a hotmelt adhesive is applied, after which the sheet is formed into a U-shaped profile (4) such that the hotmelt adhesive (9) is located on the inside of the U-shaped profile (4).

12.- Method according to any one of claims 9 to 11, characterized in that three strips (14) of assembly adhesive (11) are applied, whereby one strip (14) is placed on a location of the cover (3) corresponding to the location of the base (7) of the U-shaped profile (4).