Method and apparatus for continuously producing a semi-finished product for the production of self-sealing tyres

Patent metadata

Field	Value
Publication number	US-10723091-B2
Application number	US-201816122660-A
Country	US
Kind code	B2
Filing date	Sep 5, 2018
Priority date	Dec 20, 2013
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

An apparatus for producing a semi-finished product with a strip of sealing compound for building tyres, having at least one unsaturated styrene thermoplastic elastomer, one bonding resin and one cross-linking agent is described.

First claim

The invention claimed is:

1. An apparatus for producing a semi-finished product comprising a strip of sealing compound for building tyres, the sealing compound comprising at least the following components:
(a) at least one unsaturated styrene thermoplastic elastomer;
(b) at least one bonding resin;
(c) at least one cross-linking agent;

wherein the apparatus comprises:
a continuous mixer comprising an inner chamber and structured for receiving the components of the sealing compound and to continuously mix them until the sealing compound is obtained;
a buffer device having a respective inner chamber and coupled in series with structural continuity to the continuous mixer, downstream of the latter, in a manner such that the two respective inner chambers are physically connected without interruption;
a gear pump having a respective inner chamber and a gear system housed in the respective inner chamber, and coupled with structural continuity to the buffer device downstream of the latter, in a manner such that the two respective inner chambers are physically connected without interruption; and
an extrusion head coupled directly and with structural continuity to the gear pump, downstream of the latter, in a manner such to receive as an input the sealing compound from the gear pump and deliver as an output the sealing compound in the form of said strip having predetermined transverse size, wherein the buffer device is arranged and structured for receiving the sealing compound from the continuous mixer and for feeding the gear pump.

2. The apparatus as claimed in claim 1 , wherein the continuous mixer comprises a plurality of screws, or blades, housed in the respective inner chamber, the continuous mixer being provided with mixing portions capable of conferring to the compound a high shear stress, and with conveyor portions capable of conveying the compound being processed from one longitudinal end to the other of the inner chamber.

3. The apparatus as claimed in claim 1 , wherein the continuous mixer is a co-rotating twin screw mixer.

4. The apparatus as claimed claim 2 , wherein the continuous mixer has a diameter of the inner chamber greater than or equal to 18 mm and/or less than or equal to 420 mm, the continuous mixer being structured so that a rotation velocity of the screws is greater than or equal to 100 rpm and/or less than or equal to 1200 rpm, and with a torque greater than or equal to 20% and/or less than or equal to 90%.

5. The apparatus as claimed in claim 1 , wherein respective inner chambers of the continuous mixer, of the buffer device, of the gear pump, as well as the extrusion head, lie on the same horizontal level.

6. The apparatus as claimed in claim 1 , wherein the buffer device is a single-screw extruder comprising a single conveyor screw housed in the respective inner chamber, wherein the conveyor screw is configured for conveying the sealing compound along the major extension direction of the respective inner chamber, exerting thereon a substantially zero or very low mixing.

7. The apparatus as claimed in claim 6 , wherein the buffer device has a diameter of the respective inner chamber greater than or equal to 40 mm and/or less than or equal to 750 mm, the buffer device being structured so that a rotation velocity of the screw is greater than or equal to 15 rpm and/or less than or equal to 100 rpm.

8. The apparatus as claimed in claim 1 , further comprising
a conveyor device placed downstream of the extrusion head in a manner so as to receive said strip and convey it away from the extrusion head,
a first reel on which a service film is wound, the first reel being adapted to continuously unwind said service film on the conveyor device in a manner such that said strip exiting from the extrusion head is abutted against said service film,
a second reel on which a structural film is wound, the second reel being adapted to continuously unwind said structural film on the conveyor device in a manner such that said structural film adheres to said strip on the side opposite said service film, and
a third and/or a fourth reel, on each of which a respective elongated element is wound that is made of an elastomeric compound, the third and/or the fourth reel being adapted to continuously unwind said elongated element made of an elastomeric compound on the conveyor device in a manner such that each of said elongated elements adheres at least partially to said strip on mutually opposite sides of said strip.

9. The apparatus as claimed in claim 1 , further comprising
a collection station placed downstream of the conveyor device and configured for winding said semi-finished product on a collection reel, and
cooling means adapted to cool said strip between the outlet of the extrusion head and the collection station.

10. A plant for producing self-sealing tyres comprising the apparatus as claimed in claim 1 .

Assignees

• Pirelli

Inventors

• Monterosso Antonio
• Scurati Alberto
• Testi Stefano

Classifications

• B29B7/30 Primary

  continuous, with mechanical mixing or kneading devices · CPC title

• B29D30/0685

  Incorporating auto-repairing or self-sealing arrangements or agents on or into tyres (auto-repairing or self-sealing arrangements or agents B29C73/16; puncture preventing arrangements B60C19/12) · CPC title

• B29C73/163 Primary

  Sealing compositions or agents, e.g. combined with propellant agents · CPC title

• B29C48/387

  using a screw extruder and a gear pump · CPC title

• B29D2030/0695

  the sealant being in the form of one wide strip, e.g. a patch · CPC title