Process for producing tissue products
View Patent ↗Tissue products are disclosed containing an additive composition. The additive composition, for instance, comprises an aqueous dispersion containing an alpha-olefin polymer, an ethylene-carboxylic acid copolymer, or mixtures thereof. The alpha-olefin polymer may comprise an interpolymer of ethylene and octene, while the ethylene-carboxylic acid copolymer may comprise ethylene-acrylic acid copolymer. The additive composition may also contain a dispersing agent, such as a fatty acid. The additive composition may be incorporated into the tissue web as the web is being formed. Alternatively, the additive composition may be topically applied to the web in a post processing operation. For instance, in one embodiment, the additive composition may be applied to the web as a creping adhesive during a creping operation.
1. A process for producing a tissue product comprising:
forming a tissue web from an aqueous suspension of fibers;
conveying the tissue web through a first through-air dryer and a second through-air dryer that substantially dries the tissue web;
applying an additive composition to at least one side of the tissue web during the process, the additive composition comprising an aqueous dispersion containing a non-fibrous alpha-olefin polymer, the additive composition adhering the tissue web to a creping surface and wherein the tissue product has a bulk of greater than about 3 cc/g after the additive composition has been applied; and
creping the tissue web from the creping surface.
2. A process as defined in claim 1 , wherein the first through-air dryer and the second through-air dryer are arranged in series.
3. A process as defined in claim 2 , wherein the alpha-olefin polymer comprises an alpha-olefin interpolymer of ethylene or propylene and at least one comonomer, each comonomer being limited solely to compounds represented by the formula H 2 C═CHR, wherein R is a C 1 to C 20 linear, or branched alkyl group.
4. A process as defined in claim 2 , wherein the additive composition comprises a mixture of the olefin polymer and an ethylene-carboxylic acid copolymer.
5. A process as defined in claim 2 , wherein the additive composition is applied to the tissue web in between the first through-air dryer and the second through-air dryer.
6. A process as defined in claim 5 , wherein the additive composition is applied to the tissue web while the tissue web has a consistency of at least about 40%.
7. A process as defined in claim 2 , wherein the additive composition is applied to the tissue web after the second through-air dryer.
8. A process for producing a tissue product comprising:
forming a tissue web from an aqueous suspension of fibers;
conveying the web through a de-watering device for de-watering the tissue web, the de-watering device comprising a press belt placed adjacent to a vacuum roll and wherein the tissue web is dewatered by conveying the web on a fabric between the press belt and the vacuum roll, or the de-watering device comprising an imprinting conveyor placed adjacent to a compression nip and wherein the web is dewatered by being conveyed in between the imprinting conveyor and the compression nip;
conveying the tissue web over at least a first drying device for drying the tissue web;
applying an additive composition to at least one side of the tissue web during the process, the additive composition comprising an aqueous dispersion containing a non-fibrous alpha-olefin polymer, the additive composition adhering the tissue web to a surface of the drying device and wherein the tissue product has a bulk of greater than about 3 cc/g after the additive composition has been applied; and
creping the tissue web from the surface of the drying device.
9. A process as defined in claim 8 , wherein the alpha-olefin polymer comprises an alpha-olefin interpolymer of ethylene or propylene and at least one comonomer, each comonomer being limited solely to compounds represented by the formula H 2 C═CHR, wherein R is a C 1 to C 20 linear, or branched alkyl group.
10. A process as defined in claim 8 , wherein the additive composition comprises a mixture of the olefin polymer and an ethylene-carboxylic acid copolymer.
11. A process as defined in claim 8 , wherein the web is conveyed over a second drying device before being conveyed over the first drying device, the second drying device comprising a through-air dryer, the first drying device comprising a heated drying cylinder.
12. A process as defined in claim 8 , wherein the de-watering device comprises a first de-watering felt positioned adjacent to a first side of the imprinting conveyor, the de-watering device further comprising a second de-watering felt positioned against a second and opposite side of the imprinting conveyor, a compression nip being formed between the first de-watering felt and the first side of the imprinting conveyor, the tissue web being fed into the compression nip.
13. A process as defined in claim 11 , wherein the additive composition is applied in between the first drying device and the second drying device.
14. A process as defined in claim 11 , wherein the additive composition is applied between the de-watering device and the first drying device.
15. A process for producing a tissue product comprising:
forming a tissue web from an aqueous suspension of fibers on a forming section, the tissue web then being conveyed through a felt section, a press section, and a creping section;
conveying the tissue web into a nip formed between a shoe press roll or a suction roll of the felt section and a transfer roll of the press section, the tissue web being dewatered such that the consistency of the web is increased by 15% or more;
conveying the tissue web through a drying device for drying the web;
applying an additive composition to at least one side of the tissue web, the addictive composition adhering the tissue web to a creping surface, the additive composition comprising an aqueous dispersion containing a non-fibrous alpha-olefin polymer, and wherein the tissue product has a bulk of greater than about 3 cc/g after the additive composition has been applied; and
creping the tissue roll from the creping surface.
16. A process as defined in claim 15 , wherein the alpha-olefin polymer comprises an alpha-olefin interpolymer of ethylene or propylene and at least one comonomer, each comonomer being limited solely to compounds represented by the formula H 2 C═CHR, wherein R is a C 1 to C 20 linear, or branched alkyl group.
17. A process as defined in claim 15 , wherein the additive composition comprises a mixture of the olefin polymer and an ethylene-carboxylic acid copolymer.
18. A process as defined in claim 15 , wherein the drying device comprises a rotating heated cylinder that defines the creping surface, the tissue web being creped from the surface of the drying device.
19. A process as defined in claim 15 , wherein the transfer roll is heated.
20. A process as defined in claim 15 , wherein the additive composition is applied to the tissue web while the tissue web is being conveyed on a fabric and prior to the dryer device.
21. A process as defined in claim 18 , wherein the additive composition is applied to a surface of the heated cylinder, the additive composition transferring to the tissue web as the web is creped from the surface of the cylinder.
22. A process as defined in claim 1 , wherein the alpha-olefin polymer has a melting point of less than 120° C.
23. A process as defined in claim 8 , wherein the alpha-olefin polymer has a melting point of less than 120° C.
24. A process as defined in claim 15 , wherein the alpha-olefin polymer has a melting point of less than 120° C.