LUBRICANT RELASE AGENT COMPOSITION

Abstract

Described is the use of a composition in a process for extruding metals. Said composition includes at least one sodium and/or potassium phthalate and optionally at least one phthalate of an alkaline-earth metal.

Claims

1. A use in a process for extruding non-ferrous metals of a composition comprising at least one sodium or potassium phthalate and optionally a phthalate of an alkaline-earth metal, said composition being in the form of powder.

2. The use according to claim 1, wherein the composition comprises at least one sodium or potassium phthalate in a concentration of between 20 and 75% weight/weight, preferably between 30 and 60% w/w.

3. The use according to claim 1, wherein the composition comprises a phthalate of an alkaline-earth metal in a concentration of between 20 and 75% w/w, preferably between 30 and 60% w/w.

4. The use according to claim 1, wherein the sodium phthalate is selected from among monosodium phthalate or disodium phthalate.

5. The use according to claim 1, wherein the potassium phthalate is selected from among monopotassium phthalate or dipotassium phthalate.

6. The use according to claim 1, wherein the disodium phthalate is selected from among disodium orthophthalate and disodium terephthalate.

7. The use according to claim 6, wherein the disodium phthalate is disodium orthophthalate.

8. The use according to claim 1, wherein the composition consists of disodium phthalate.

9. The use according to claim 1, wherein the composition has a grain size of between 10 and 150 μm.

10. The use according to claim 9, wherein the composition has a grain size of between 5 and 120 μm.

11. The use according to claim 1, wherein the composition is applied on at least one surface of a head of a piston of an extrusion press and/or on at least one surface of a billet of a non-ferrous metal.

12. The use according to claim 1, wherein the composition also comprises at least one solid pigment, preferably said at least one solid pigment is selected among: talc, mica, boron and graphite nitride, or other minerals.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0014] FIG. 1 shows a diagram of a press 1 for the extrusion of a metal.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The invention relates to the use of a composition in a process for extruding metals. Said composition comprises at least one sodium and/or potassium phthalate and optionally at least one phthalate of an alkaline-earth metal.

[0016] According to an embodiment, the composition is in the form of powder. Preferably, the composition is in the form of powder with a grain size of between 10 and 150 μm, more preferably between 5 and 120 μm.

[0017] According to an embodiment, the sodium phthalate is selected between monosodium phthalate and/or disodium phthalate. Preferably, the disodium phthalate is selected from among disodium orthophthalate and disodium terephthalate. According to a preferred embodiment, the disodium phthalate is orthophthalate disodium.

[0018] According to a further embodiment, the potassium phthalate is selected from among monopotassium phthalate or dipotassium phthalate.

[0019] Preferably, the phthalate of an alkaline-earth metal is selected from between an orthophthalate calcium or magnesium salt or isophthalate or terephthalate. According to an embodiment, the composition comprises at least one solid pigment, preferably said at least one solid pigment is selected from among: talc, mica, boron or graphite nitride, or other minerals.

[0020] According to a preferred embodiment, the composition comprises orthophthalate disodium optionally in a mixture with at least one phthalate of an alkaline-earth metal.

[0021] According to an embodiment, the composition comprises the sodium or potassium phthalate in a concentration of between 20 and 75% weight/weight, preferably between 30 and 60% w/w.

[0022] According to an embodiment, the composition comprises at least a phthalate of an alkaline-earth metal in a concentration of between 20 and 75% weight/weight, preferably between 30 and 60% w/w.

[0023] According to a preferred embodiment, the composition consists of disodium phthalate.

[0024] According to an embodiment, the composition is applied on at least one surface 101 of a head 100 of a piston 10 of an extrusion press 1 and/or on at least one surface 201 of a metal billet 20. Preferably, the composition is applied before the start of the extrusion process in order to facilitate the detachment of the surface 101 of the head 101 of the piston 10 from the billet 20 at the end of the extrusion process. Preferably, the extrusion process is a process for extruding a non-ferrous metal, more preferably made of aluminium or copper or alloys thereof with other metals.

[0025] According to an embodiment, the composition is applied on the at least one surface 101 of the head 100 of the piston 10 of the press 1 and/or on the at least one surface 201 of the metal billet 20 with systems and methods known to an expert in the trade. Preferably, the composition is applied by means of a spray, preferably using an electrostatic type spray system.

[0026] The Applicant has surprisingly found that the composition according to the invention is able to prevent the metal of the billet 20 from sticking to the head 100 of the piston 10 or remaining welded thereto and, therefore, the piston 10 remaining locked, or creating damage due to breakage of the tools of the press 1 when retracting. The composition can be therefore be defined as a lubricant release agent.

[0027] The composition according to the invention has a melting point of between 400 and 450° C., slightly less than or equal to the extrusion process temperatures. For this reason, after its application on the at least one surface 101 of the head 100 of the piston 10 of the press 1 and/or on the at least one surface 201 of the metal billet 20 it starts to melt thanks to the high temperature of the billet 20 or the head 100 of the piston 10 and to spread spontaneously on the treated surface. The subsequent compression between the head 100 of the piston 10 and the billet 20 leads to the complete stretching of a film which covers the entire surface in contact forming a complete and continuous barrier film.

[0028] Moreover, the use of the composition according to invention reduces the consumption with respect to boron nitride, since the product does not create static accumulations of powder, but always covers the surface regardless of how small the quantity applied.

[0029] In order to reduce the consumption of the costly boron nitride as much as possible, a grain size of between 2 and 30 microns is used with an average value of around 10 microns, such as to guarantee a covering capacity of 5-15 m.sup.2/g. The composition according to the invention comprises sodium or potassium phthalate with a much greater grain size, of between 20 and 100 microns, due to the melting property which increases the covering capacity. This means that during the spray dispensing the boron nitride tends to spread in the surrounding space more intensely and rapidly compared to sodium or potassium phthalate, which, on the other hand, reaches the surface to be treated due to the electrostatic charge, without further spreading into the air. In this way, the composition spreads very little outside the treated surfaces, avoiding affecting the press 1, the peripherals of the press and the surrounding environments. Above all, the extent of the amount inhaled by the operators present in the proximity of the machine is lower. Lastly, this reduces defects due to inclusions and streaks of the profiled sections 40 obtained with the composition according to the invention.