Ply fibrous product
A ply fibrous product comprises at least one ply selected from a nonwoven ply and a tissue paper ply, wherein the at least one ply selected from a nonwoven ply and a tissue paper ply comprises cellulosic fibers comprising an organic polycarboxylic acid and wherein the organic polycarboxylic acid has at least one carboxyl group covalently bound to the cellulosic fibers and at least one free carboxyl group. Due to the presence of covalent chemical bonds between a carboxyl group of the polycarboxylic acid and hydroxy groups of the cellulosic fibers present in all substrates, the ply fibrous products display a long-lasting acidic pH even after having been rinsed with water. In some embodiments a long-lasting acidic pH may be achieved in the nonwovens treated with an organic polycarboxylic acid even after washing with a washing detergent.
1. A ply fibrous product comprising at least one nonwoven ply, wherein the nonwoven ply comprises cellulosic fibers, wherein said nonwoven ply is treated with an organic polycarboxylic acid, and wherein the organic polycarboxylic acid has at least one carboxyl group covalently bound to the cellulosic fibers and at least one free carboxyl group, wherein a surface of the ply fibrous product has a pH after washing in a range of from 2.0 to 5.0, and
wherein the nonwoven ply comprises
(A) cellulosic fibers selected from
(A1) natural fibers,
(A2) semi-synthetic fibers, and
(A3) a mixture of natural fibers and semi-synthetic fibers,
wherein the nonwoven ply optionally comprises
(B) synthetic fibers selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, and polyester.
2. The ply fibrous product according to claim 1 , wherein the organic polycarboxylic acid has two to ten carboxyl groups.
3. The ply fibrous product according to claim 1 , wherein the organic polycarboxylic acid has 2 to 12 carbon atoms in a main chain.
4. The ply fibrous product according to claim 1 , wherein at least one carboxyl group is covalently bound to the cellulosic fibers by forming an ester group with a cellulosic hydroxy group.
5. The ply fibrous product according to claim 1 ,
wherein the weight proportion of cellulosic fibers based on the total weight of the ply fibrous product is 10 to 80 wt.-%, and
wherein the weight proportion of synthetic fibers based on the total weight of the ply fibrous product is 20 to 90 wt.-%.
6. The ply fibrous product according to claim 1 , wherein the ply fibrous product is a multiply tissue product including the nonwoven ply.
7. The ply fibrous product according to claim 1 , wherein the product is selected from handkerchiefs, napkins, paper hand towels, facial tissues, wound care dressings and cleaning wipes.
8. The ply fibrous product according to claim 1 , wherein the cellulosic fibers comprising an organic polycarboxylic acid are obtainable by treating cellulosic fibers with an organic polycarboxylic acid, in the presence of an activator.
9. The ply fibrous product according to claim 8 , wherein the activator is selected from the group consisting of sodium hypophosphite monohydrate, N-N′-carbonyldiimidazole, p-toluenesulfonylchloride and N,N′-dicyclohexyl-carbodiimide in combination with 4-pyrrolidino-pyridine or 4-dimethylaminopyridine.
10. The ply fibrous product according to claim 1 , wherein the surface of the ply fibrous product has a pH after rinsing in a range of from 2.0 to 5.5.
11. The ply fibrous product according to claim 1 , wherein the product is:
(I) antibacterial wipe for personal hygiene,
(II) wound care dressing,
(III) antibacterial wipe for food service cleaning, at home and in food production, or
(IV) as cleaning wipe suitable to clean surfaces.
12. A method for reducing the amount of unwanted bacteria or inhibiting their growth, the method comprising using the ply fibrous product of claim 1 , wherein the unwanted bacteria are selected from the group consisting of E. coli, E. faecalis, S. epidermidis, S. aureus and K. pneumonia.
13. The method according to claim 12 , wherein the log CFU/ml of unwanted bacteria is reduced at least 5%.
14. The ply fibrous product according to claim 1 , wherein the organic polycarboxylic acid is citric acid.
15. The ply fibrous product according to claim 1 , wherein the at least one free carboxyl group is configured to release a proton.
16. Method for producing a ply fibrous product comprising at least one nonwoven ply, wherein the nonwoven ply comprises cellulosic fibers, the method comprising the steps of
(α) treating the nonwoven ply comprising the cellulosic fibers with a treatment solution comprising one or more organic polycarboxylic acid, or optionally a mixture of one or more organic polycarboxylic acids with salts thereof, and an activator;
(β) optionally drying; and
(γ) curing to obtain the ply fibrous product,
wherein a surface of the ply fibrous product has a pH after washing in a range of from 2.0 to 5.0, and
wherein the nonwoven ply comprises
(A) cellulosic fibers selected from
(A1) natural fibers,
(A2) semi-synthetic fibers, and
(A3) a mixture of natural fibers and semi-synthetic fibers,
wherein the nonwoven ply optionally comprises
(B) synthetic fibers selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, and polyester.
17. The method according to claim 16 , wherein at least one of the following conditions are fulfilled:
(i) the concentration of the organic polycarboxylic acid in the treatment solution is 2 to 80 wt.-% based on the total weight of the treatment solution,
(ii) the treatment time is 10 sec to 2 h,
(iii) the curing time is 1 to 10 min,
(iv) the curing temperature is 100° C. to 200° C.