Package for hot-melt adhesives and method of production thereof

Abstract

 A package for hot-melt adhesives consisting in a pre-shaped prismatic container (1), obtained by hot-drawing (140-170°C) of a sheet of silicon-coated paper by means of a heated mould (6).

Description

[0001] The present invention relates to the packaging of hot-melt adhesives, of the pressure-sensitive type, and in particular to a substantially prismatic container obtained by drawing a sheet of silicon-coated paper.

[0002] It is known that hot-melt pressure-sensitive adhesives reach the packaging step in the melt state and they are poured into packages of silicon-coated paper at a temperature of about 200°C, which common package glues can not withstand.

[0003] Owing to this reason, the presently used packages consist of parallelepipeds obtained by dinking and embossing sheets of silicon-coated paper, which are then manually folded to form the packages. The use of this type of paper is made necessary by the stickiness of this type of adhesives. Each of these packages is then inserted into a cell of a containment grid positioned into a box. Since standard boxes include 12 adhesive packages of 1 kg each or 24 packages of ½ kg each, the intensive labour required by the manual folding of these packages is apparent. Moreover, a possible mechanical folding would be achievable only by means of a quite expensive apparatus, due to the fairly complicated folding sequence.

[0004] In the light of the above, the waste of time required by the manual folding, as well as the difficulty in mechanizing the folding process are clear.

[0005] Therefore, the object of the present invention is to provide a type of package suitable for hot-melt pressure-sensitive adhesives which does not require labour for its production, as well as a method for the production of this type of package.

[0006] This object is achieved by means of a package for hot-melt pressure-sensitive adhesives having the characteristics cited in claim 1. The relevant method of production is characterized by the steps cited in claim 2.

[0007] The first apparent advantage of the package and method of the present invention is the significant saving of time and/or costs resulting from the elimination of the manual or mechanical package folding process, since the package according to the present invention is ready for use as it comes out of the production plant.

[0008] A second advantage stems from the fact that the embossing step of the sheets of silicon-coated paper is eliminated from the method of the invention, since dinking is immediately followed by drawing.

[0009] A further advantage of the present package is that it is much easier to be handled when empty since it does not risk to come undone like folded packages, its shape being the result of a permanent bending.

[0010] These and other advantages and characteristics of the package according to the present invention and of the relevant method of production will be apparent from the following detailed description of a preferred embodiment thereof, reported as a non-limiting example, referring to the annexed drawings wherein:

Fig.1 is a side sectional view of the mould, at the end of the drawing process of the sheet of silicon-coated paper;

Fig.2 is a perspective view of a package according to the present invention;

Fig.3 is a top plan view of the lower part of the mould; and

Fig.4 is a bottom plan view of the upper part of the mould.

[0011] Referring to fig.1, there is seen a sheet 1 of silicon-coated paper which is drawn by a mould made up of an upper male part 2 reciprocating vertically according to arrow A, carried by stem 3, and pressing said sheet 1 inside a lower female part 4. The male part 2 includes an outer member 5 abutting on the plane of the female part 4, whereas a central punch 6 continues the downward run and enters a die 7. The latter also includes a peripheral groove 8 into which sheet 1 is pressed by the edge of punch 6 in order to obtain an upper peripheral lip, which gives greater structural stiffness to the package.

[0012] This process takes place at a mould temperature included between 140°C and 170°C, so that sheet 1 retains the shape given thereto by said mould, which is heated by proper means, e.g. by built-in electric resistors (not shown). In this regard, it should be noted that the mould is preferably provided with a control system (not shown) controlling the operating temperature and/or pressure according to the thickness of the sheet 1 to be drawn.

[0013] Referring to fig.2, there is seen that a square package 9 according to the present invention has an upper peripheral lip 10, as mentioned above, and "bellow" pleats 11 at the corners. These pleats 11 result from the drawing process of a square sheet with rounded angles, and they allow to open and flatten the package for taking out the adhesive which, when solidifying upon cooling, tends to stick to the package sides.

[0014] Referring finally to figs.3 and 4, the plan views of the female part 4 and male part 2 of the mould show the engravings 12, on the female part 4, and the engravings 12' complementary thereto, on the male part 2, which cooperate in forming the corner pleats 11.

[0015] Clearly, the square shape of the above-illustrated package is merely an example, since the shape and size of the package according to the present invention can be freely adapted to the specific needs of the user.

[0016] It should also be noted that during the dinking step of the sheets of silicon-coated paper, the method of the present invention provides for a smaller waste, since it is only required to round off the angles of a regular shape (square, rectangular, etc.). On the contrary, prior art packages require shapes with projecting portions which imply a higher waste.

[0017] Therefore, possible additions and/or modifications may be made to the package of the present invention and to the relevant method of production, particularly with regard to the shape of the package and of the corresponding mould, yet without departing from the scope of protection of the invention.

Claims

1. A package for hot-melt adhesives characterized in that it consists of a pre-shaped prism (7) of silicon-coated paper.

2. A method of production of the package according to claim 1, including dinking of a sheet (1) of silicon-coated paper, characterized in that it further includes hot-drawing of said dinked sheet (1) by means of a heated mould made up of a female part (4) and a male part (2).

3. A method according to claim 2, characterized in that it includes adjusting, by means of a control system, the mould temperature and/or pressure according to the thickness of the sheet (1) to be drawn.

Drawing