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

Patent metadata

Field	Value
Publication number	US-10131101-B2
Application number	US-201415039377-A
Country	US
Kind code	B2
Filing date	Nov 21, 2014
Priority date	Dec 20, 2013
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

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

First claim

The invention claimed is:

1. A method 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;

the method comprising:
feeding the components of the sealing compound in a continuous mixer comprising an inner chamber, and mixing the components while they advance in the continuous mixer until the sealing compound is obtained;
subsequently continuously feeding the sealing compound from the continuous mixer directly to 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;
subsequently advancing the sealing compound along the buffer device, absorbing possible flow rate pulses of the sealing compound coming from the continuous mixer, in a manner so as to continuously feed the sealing compound to 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
subsequently continuously feeding, by means of the gear pump, the sealing compound to an extrusion head coupled directly and with structural continuity to the gear pump, in a manner so as to obtain, in output from said extrusion head, said strip of sealing compound with predetermined transverse size.

2. The method as claimed in claim 1 , wherein a temperature of the sealing compound at an outlet of the extrusion head is greater than or equal to 60° C. and/or less than or equal to 160° C. and wherein a flow rate of the sealing compound is greater than or equal to 30 kg/h and/or less than or equal to 5000 kg/h.

3. The method as claimed in claim 1 , wherein the sealing compound further comprises at least one diene elastomer and/or at least one plasticising agent and/or at least one reinforcement filler and/or at least one peptising agent.

4. The method as claimed in claim 1 , wherein the sealing compound comprises from 20 to 100 phr of at least one unsaturated styrene thermoplastic elastomer, from 0 to 80 phr of at least one synthetic or natural diene elastomer, from 20 to 200 phr, preferably from 30 to 150 phr, of at least one bonding resin, from 0.1 to 6 phr of at least one cross-linking agent.

5. The method as claimed in claim 1 , wherein the buffer device reduces the amplitude and/or the frequency of the instantaneous flow rate pulses in its inner chamber with respect to the amplitude and/or frequency of the pulses in the inner chamber of the continuous mixer.

6. The method as claimed in claim 1 , wherein the sealing compound, in a passage from the continuous mixer to a first portion of the inner chamber of the buffer device, proximal to the continuous mixer, undergoes a fall of pressure.

7. The method as claimed in claim 1 , wherein the buffer device lower a temperature of the sealing compound during its travel along its respective inner chamber, the difference between the temperature at an inlet and that at an outlet of the buffer device being greater than or equal to 5° C.

8. The method as claimed in claim 1 ,
wherein said strip has a profile, taken along an orthogonal section, having two opposite greater sides with length greater than a mutual maximum distance,
wherein the method further comprises:
conveying said strip away from the extrusion head,
continuously unwinding a service film in a manner such that said strip exiting from the extrusion head is abutted against said service film,
continuously unwinding a structural film in a manner such that said structural film adheres to said strip, and
continuously unwinding a first and a second elongated elements made of an elastomeric compound in a manner such that said elongated elements at least partially adhere to said strip, thereby producing the semi-finished product that further comprises:
the service film adherent to one of said greater sides,
the structural film adherent to said strip on a side opposite said service film, and
the first and the second elongated elements made of the elastomeric compound, in partial adhesion to said strip on mutually opposite sides of said strip and at least partially arranged transverse to said greater sides.

9. A process for producing self-sealing tyres, comprising:
building, vulcanising and moulding green tyres,
wherein the building of the green tyres includes producing a semi-finished product comprising a strip of sealing compound in accordance with the method as claimed in claim 1 .

Assignees

• Pirelli
• Pirelli

Inventors

• Monterosso Antonio
• Scurati Alberto
• Testi Stefano

Classifications

• B29D2030/0695

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

• B29C47/884

  Operations & Transport · mapped topic

• B29C47/367

  Operations & Transport · mapped topic

• B29K2025/04

  Polymers of styrene · CPC title