Process and Apparatus for Extruding Bands of Material onto a Substrate

Abstract

A extrusion process and apparatus for the deposition of precise, usually small amounts of extrudate (4) for adhesion to a substrate (1) comprising an extruder (2) positioned close to the substrate (1) and a jet of hot gas (6) directed onto the extrudate (1) between the extruder (2) and the substrate (1) in order to retain the adhesive properties between the extrudate (4) and the substrate (1).

Claims

1. A process for the application of a heat flowable adhesive material to a substrate comprising extruding the heat flowable material from an extrusion die wherein the extrusion die and the substrate are moved relative to each other to deposit the heat flowable material on the surface of the substrate and a gas at a temperature in the range 40° C. to 150° C. is blown at a pressure in the range 1 to 8 bars (0.1 Mpa to 0.8 Mpa) onto the side of the heat flowable material remote from the substrate characterised in that a distance is provided between the die of the extruder and the surface of the substrate to prevent interaction between them.

2. A process according to claim 1, wherein the distance is more than 0.5 mm.

3. A process according to claim 2, wherein the distance between the die of the extruder and the substrate is from 0.5 mm to 2 cms.

4. A process according to claim 1, wherein the hot gas is blown at a temperature in the range 40° C. to 110° C.

5. A process according to claim 1, wherein the gas is blown at a pressure of 0.2 to 0.3 Mpa.

6. A process according to claim 1, wherein the gas is blown onto the heat flowable material as it leaves the die of the extruder and as it is deposited on the substrate.

7. A process according to claim 1, wherein the hot gas is air.

8. A process according to claim 1, wherein the extruder is a robotic mini-extruder.

9. A process according to claim 1, wherein the material is a thermally activatable material and is deposited on the substrate at a temperature below the activation temperature of the material.

10. A process according to claim 1, wherein the material is extruded at a temperature in the range of 60° C. to 120° C.

11. A process according to claim 1, wherein the extrusion is intermittent.

12. A process according to claim 1, wherein the hot gas is applied from jets located adjacent to the extrusion die that are integrated with the extrusion die.

13. A process according to claim 1, wherein the heat flowable adhesive is applied to a series of substrates that are sequentially located adjacent to the die of the extruder.

14. An apparatus for the application of a heat flowable adhesive material to a series of substrates comprising an extruder for extruding the heat flowable material from a die, a line for the provision of a series of substrates to a location which is more than 0.5 mm from the extrusion die and the substrate, means for moving the die and the substrate relative to each other to deposit the heat flowable material on the surface of the substrate and one or more gas jets to supply gas at a temperature in the range 40° C. to 150° C. and at a pressure in the range 0.1 Mpa to 0.8 Mpa onto the side of the heat flowable material remote from the substrate.

15. An apparatus according to claim 14, wherein the hot gas is blown at a temperature in the range of 40° C. to 110° C.

16. An apparatus according to claim 14, wherein the hot gas is blown at a pressure of 0.2 to 0.3M pa.

17. An apparatus according to claim 14, wherein the gas jet is positioned to blow the gas onto the heat flowable material as it leave the die of the extruder and as it is deposited on the substrate.

18. An apparatus according to any of claim 14, wherein the extruder is a robotic mini-extruder.

Description

[0048] The invention is illustrated by reference to the accompanying drawings in which

[0049] FIG. 1 shows an extrusion system according to the present invention and

[0050] FIG. 2 shows a substrate provided with an extruded strip by the process of the present invention.

[0051] FIG. 1 shows a series of substrates (1) which are moving from right to left in the figure. The substrates move so that they are sequentially positioned below the nozzle (3) of the mini extruder (2) from which a strip of material (4) is extruded. Hot air (6) is blown onto the extrudate (4) from the hot air blower (5). The material (4) is of width (d) and is held by the hot air (6) at the temperature required for it to adhere to the substrate (1) to produce a thin strip of the extrudate (4) in the substrate (1) as shown in FIG. 2.

[0052] FIG. 1 also illustrates the X, Y and Z directions referred to in this application.