Paper making and fiber liberation – Processes and products – Plural fiber containing
Patent
1992-08-12
1994-01-11
Chin, Peter
Paper making and fiber liberation
Processes and products
Plural fiber containing
162152, 162156, 1621681, 162169, 162183, D21H 1734
Patent
active
052777634
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a porous and flexible product in sheet form, containing elastomer powder. The invention also relates to its composition and to its manufacturing process.
More particularly, the invention relates to a porous and flexible product in sheet form which comprises at least one elastomer in powder form, organic and/or inorganic fibers, and optionally other additives. The invention also relates to the process for manufacturing said sheet product by the wet method, and in particular by the papermaking method.
The products in sheet form described in Applicant's patent EP-6 390 give materials with insufficient porosity and flexibility to meet certain demands of the market of base materials for floor coverings in thick polyvinyl chloride.
Accordingly, the Applicant has confirmed the impossibility of improving satisfactorily the flexibility of these products by increasing the proportion of latex incorporated in bulk, or by addition of latex by an impregnation technique.
Moreover, such additions create known problems of bubbling and blistering of the layers of plasticols during transformation due to a lack of porosity in the base material.
Indeed, elastic products in sheet form are already known, namely products with a high level of breaking elongation. The manufacture of such products requires the introduction of a large quantity of elastomer in solution, dispersion or emulsion form. These elastomers in such forms permit the formation of a continuous film after elimination by drying of the dissolving, emulsifying or suspending medium. This film-forming property of the elastomer confers to the material a high elasticity, a good internal cohesion, but a very poor porosity.
Various techniques are used, singly or in combination, for introducing these elastomers, for example:
flocculation of latex of elastomers in bulk. This technique does not allow the introduction of more than 30% of elastomer, on a papermaking machine, with respect to the rest of the components. Indeed, elastomers are soft products, very sticky, causing clogging by deposition in the circuits and on the web of the papermaking machine. Moreover, said flocculation technique has the disadvantage of causing, in the presence of organic and/or inorganic fibers and independently of the flocculation of the latex necessary to its retention, the flocculation of the fibers, which strongly affects the homogeneity of the material,
deposition by spraying on the dry or wet sheet. This deposition demands extra equipment and does not permit a homogeneous introduction of high quantities of elastomers in the thiskness of the material,
deposition by impregnation of the dry or wet sheet. This deposition is limited by the sheet absorbing power and requires very expensive extra equipment (impregnating machine). This last technique is the most commonly used. Among known materials are the celloderm materials which are constituted by a cellulose sheet, in which one or more latex of elastomers are incorporated by impregnation at wet end section of the papermaking machine. This manufacturing technique leads to an important clogging of the cellulosic sheet.
In all cases, such additional treatments affect rather considerably the running speed of the papermaking machine and create extra consumption of energy for eliminating the dissolving, dispersing or emulsifying medium.
Moreover, and as already indicated, the film-forming property of the elastomer introduced by said techniques, leads to products which are elastic but low in porosity, all the more so as high proportions of elastomers are incorporated.
French Patent Application FR-2-514 015 relates to compositions comprising fibrillae of polyolefins with which flexible heat-strengthened sheets can be obtained economically, showing a good ability to deep heat-shaping. Said compositions contain particles of a rubbery material. The sheets which show very poor internal cohesion, are strengthened by heating up to a temperature higher than the softening point of the polyolefin fibers.
It is therefore the obje
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patent: 4002527 (1977-01-01), Piersol
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patent: 4510019 (1985-04-01), Bartelloni
patent: 4645565 (1987-02-01), Vallee et al.
Bost, "Matiere Plastiques-Chimie-Applications," Technique & Documentation, Apr. 1974, pp. 188-189.
Debaux Bernard
Fredenucci Pierre
Arjo Wiggins S.A.
Chin Peter
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