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US 4,379,465 AGranted
Process for producing a filtering structure in particular for cigarette filters
AssigneeJob, anciens Ets Bardou Job & Pauilac
InventorFrancois Coq
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AssigneeJob, anciens Ets Bardou Job & Pauilac
InventorFrancois Coq
Estimating the term…
Process for producing a filtering structure, in particular for cigarette filters from a fibrous mass comprising a homogeneous mixture of fibres of different types. Some of the fibres are necessarily thermofusible synthetic fibres having a low melting point and adhesive properties in the molten state, and the others are absorbent with respect to harmful products of tobacco smoke and stable at the melting temperature of the thermofusible fibres. The fibrous mixture is shaped into a cylindrical rod which is in state which is not yet coherent but homogeneous and comprises fibrous networks which are closely imbricated relative to each other. According to the invention, the process comprises employing a notable proportion of thermofusible fibres relative to the absorbent fibres, bringing the fibrous mixture to a temperature which leaves the absorbent fibres intact but which is high enough to melt and fluidify all the thermofusible material which, initially present in the form of fibres, is converted into fine droplets dispersed in the network of absorbent fibres. This conversion created, on one hand, multiple connections at the crossing points of the absorbent fibres, which remained stable and, on the other hand, a network of pores which intercommunicate in all directions and are constituted by spaces left empty upon the melting of the thermofusible fibres. This process is applicable in particular to the production of a filtering structure for cigarette filters.
In a process for producing a filtering structure, in particular for cigarette filters, comprising, mixing fibres of different types to form a homogeneous fibrous mass, one type of the fibres being synthetic and thermofusible at a low melting point and possessing adhesive properties in the molten state, another type of the fibres being absorbent with respect to harmful products of tobacco smoke and stable at the melting temperature of the thermofusible fibres, shaping the fibrous mass into a cylindrical rod which is not yet in a coherent state but is homogeneous and comprises fibrous networks which are closely imbricated relative to each other, the improvement comprising:
A filter for cigarettes, said filter being originally formed of a homogeneous fibrous mass of different types of fibers closely imbricated relative to each other, one type of fibres being elongated and comprising polyolefin material thermofusible at a low melting point and possessing adhesive properties in the molten state, the polyolefin fibres being fibrillated fibres of high-density polyethylene for paper use assembled in very fibrillated and very abundant fibrous bundles having a very irregular and very hairy surface of high specific area, the main length of said fibres varying between 1 and 2 mm and their diameter varying between 2 and 25 microns, another type of fibre being absorbent with respect to the harmful products of tobacco smoke and stable at the melting temperature of the thermofusible fibres, said mass containing a notable portion of thermofusible fibres relative to the absorbent fibres, said mass being shaped into a rod-like form and having been converted, by exposure to a temperature greater than the melting temperature of the elongated thermofusible fibres, to one in which fine droplets of said synthetic material are dispersed among the absorbent fibres to form multiple connections at crossing points, said mass containing a network of pores intercommunicating in all directions and formed of the speces left empty upon the complete melting of the thermofusible fibres.
A filter for cigarettes, said filter being originally formed of a homogeneous fibrous mass of different types of fibres closely imbricated relative to each other, one type of fibres being elongated and comprising synthetic material thermofusible at a low melting point and possessing adhesive properties in the molten state, another type of fibre being absorbent with respect to the harmful products of tobacco smoke and stable at the melting temperature of the thermofusible fibres, said mass containing a notable portion of thermofusible fibres relative to the absorbent fibres, said mass being shaped into a rod-like form and having been converted, by exposure to a temperature greater than the melting temperature of the elongated thermofusible fibres, to one in which fine droplets of said synthetic material are dispersed among the absorbent fibres to form multiple connections at crossing points, said mass containing a network of pores intercommunicating in all directions and formed of the spaces left empty upon the complete melting of the thermofusible fibres, said fibrous mass comprising 50% fibrillated fibres of high-density polyethylene for paper use and 50% pine cellulose fibres, the characteristics of shape, fineness, and overall size of these fibres imparting a low density to the fibrous mass after the shaping thereof.
Dependencies are inferred from the claim text.