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 application of a heat flowable adhesive material to a substrate comprising: a) extruding the heat flowable adhesive material from an extrusion die of an extruder; wherein the extrusion die and the substrate are moved relative to each other to deposit the heat flowable adhesive material on a surface of the substrate; wherein the heat flowable adhesive material has a thickness of about 0.2 mm or greater and about 0.6 mm or less; b) blowing a gas at a temperature in a range of 40? C. to 150? C. at a pressure in a range of 1 to 8 bars (0.1 Mpa to 0.8 Mpa) onto a side of the heat flowable adhesive material remote from the substrate and between the extrusion die and the substrate to retain adhesive properties between the heat flowable adhesive material and the substrate; wherein the distance between the extrusion die of the extruder and the surface of the substrate is from 0.5 mm to 2 cm to prevent interaction between them; and wherein a direction of rotation of a screw of the extruder is reversible to stop extrusion.

2. The process according to claim 1, wherein the gas is blown at a temperature in the range of 40? C. to 110? C.

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

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

5. The process according to claim 1, wherein the gas is air.

6. The process according to claim 1, wherein the extruder is a robotic mini-extruder.

7. The process according to claim 1, wherein the heat flowable adhesive material is a thermally activatable material and is deposited on the substrate at a temperature below an activation temperature of the material.

8. The process according to claim 1, wherein the heat flowable adhesive material is extruded at a temperature in the range of 60? C. to 120? C.

9. The process according to claim 1, wherein the extruding is intermittent.

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

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

12. The process according to claim 1, wherein a residence time of the heat flowable adhesive material within the extruder is less than 10 minutes.

13. The process according to claim 1, wherein the heat flowable adhesive material is an expandable material.

14. An apparatus for application of a heat flowable adhesive material to a series of substrates comprising: an extruder for extruding the heat flowable adhesive material from a die, wherein the heat flowable adhesive material has a thickness of about 0.2 mm or greater and about 0.6 mm or less, wherein a residence time of the heat flowable adhesive material within the extruder is less than 10 minutes, and wherein a direction of rotation of a screw of the extruder is reversible to stop extrusion; a line for provision of a series of substrates to a location which is between 0.5 mm and 2 cm from the die to the series of substrates; means for moving the die and the series of substrates relative to each other to deposit the heat flowable adhesive material on a surface of the series of substrates; and one or more gas jets to blow gas at a temperature in a range of 40? C. to 150? C. and at a pressure in a range of 0.1 Mpa to 0.8 Mpa onto a side of the heat flowable adhesive material remote from the series of substrates and between the extruder and the substrates.

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

16. The apparatus according to claim 14, wherein the gas is blown at a pressure of 0.2 Mpa to 0.3 Mpa.

17. The apparatus according to claim 14, wherein the one or more gas jets is positioned to blow the gas onto the heat flowable adhesive material as it leaves the die of the extruder and as it is deposited on the series of substrates.

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

19. The apparatus according to claim 14, wherein the residence time of the heat flowable adhesive material within the extruder is less than 5 minutes.

20. The apparatus according to claim 14, wherein the heat flowable adhesive material is an expandable material.

Description

(1) The invention is illustrated by reference to the accompanying drawings in which

(2) FIG. 1 shows an extrusion system according to the present invention and

(3) FIG. 2 shows a substrate provided with an extruded strip by the process of the present invention.

(4) 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.

(5) FIG. 1 also illustrates the X, Y and Z directions referred to in this application.