SUBSTRATE FOR EFFICIENT USE IN SANITIZING AND DISINFECTING

Abstract

The current invention relates to modifying the surface of a cellulose-containing nonwoven substrate carrying a quaternary ammonium compound. A material for a nonwoven disinfecting wipe is provided which material includes a nonwoven substrate comprising cellulose and synthetic fibers and a combination of poly(vinylamine) and poly(amideamine-epichlorohydrin). Further, a method is provided for preparing a material for a nonwoven disinfecting wipe, the method comprising treating a nonwoven substrate comprising cellulose with poly(vinylamine) and poly(amideamine-epichlorohydrin).

Claims

1-8. (canceled)

9. A nonwoven material comprising: a nonwoven fibrous substrate comprising cellulosic fibers and synthetic fibers; and a cross-linked polymer network comprising a polyvinylamine polymer and a poly(amideamine-epichlorohydrin) polymer disposed about the cellulosic and synthetic fibers of the nonwoven fibrous substrate.

10. The nonwoven material of claim 9, further comprising a cationic antimicrobial compound absorbed within the nonwoven fibrous substrate, wherein the cross-linked polymeric network improves release of the cationic antimicrobial compound from the nonwoven fibrous substrate during use relative to a nonwoven fibrous substrate without the cross-linked polymeric network.

11. The nonwoven material of claim 10, wherein the cationic antimicrobial compound comprises a quaternary ammonium compound.

12. The nonwoven material of claim 9, wherein the synthetic fibers are selected from the group consisting of polypropylene, polyester, polylactic acid, polyethylene terephthalate, and glass.

13. The nonwoven material of claim 9, wherein the cellulosic fibers are selected from the group consisting of wood pulp, viscose, rayon, cotton, hemp, jute, and flax.

14. The nonwoven material of claim 9, wherein the cellulosic and synthetic fibers are hydroentangled.

15. The nonwoven material of the claim 9, where the nonwoven material has a basis weight of 25-120 gsm.

16. The nonwoven material of claim 9, wherein the cross-linked polymer network is functionalized with silver nanoparticles.

17. The nonwoven material of claim 9, wherein the polyvinylamine polymer (PVAm) is present in an amount greater than an amount of the poly(amideamine-epichlorohydrin) polymer (PAE).

18. The nonwoven material of claim 9, wherein a ratio of the polyvinylamine polymer (PVAm) to the poly(amideamine-epichlorohydrin) polymer (PAE) is from 3:1 to 8:1.

19. A process for preparing a nonwoven material comprising: treating a nonwoven fibrous substrate comprising cellulosic fibers and synthetic fibers with a mixture of a polyvinylamine polymer and a poly(amideamine-epichlorohydrin) polymer, to form a cross-linked polymeric network about said cellulosic fibers and synthetic fibers of the nonwoven fibrous substrate.

20. The process of claim 19, further comprising: after the treating, contacting the nonwoven fibrous substrate with a cationic antimicrobial compound to absorb the cationic antimicrobial compound within the nonwoven fibrous substrate, wherein the cross-linked polymeric network improves release of the cationic antimicrobial compound from the nonwoven fibrous substrate relative to a nonwoven fibrous substrate without the cross-linked polymeric network.

21. The process of claim 20, wherein the cationic antimicrobial compound comprises a quaternary ammonium compound.

22. The process of claim 20, further comprising drying the nonwoven fibrous substrate after the treating and before the contacting.

23. The process of claim 19, wherein the cellulosic and synthetic fibers are hydroentangled.

24. The process of claim 19, wherein, during the treating, the polyvinylamine polymer (PVAm) is present in an amount greater than an amount of the poly(amideamine-epichlorohydrin) polymer (PAE).

Description

BRIEF DESCRIPTION OF THE FIGURE

[0023] FIG. 1 is a schematic illustration of the three-dimensional network bonding between poly(vinylamine) and poly(amideamine-epichlorohydrin) around the cellulosic fiber.

DETAILED DESCRIPTION

[0024] A nonwoven web is pre-formed, preferably by a hydroentanglement process. According to the invention, the nonwoven web is provided with a cationic charged network formed by the two polymers poly(vinylamine) (PVAm)

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[0025] and poly(amideamine-epichlorohydrin) (PAE)

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[0026] which are both cationic in charge and water soluble. PAE is formed by the reaction of a polyamideamine having secondary amine groups with epichlorohydrin. Part of the amine groups react with the epichlorohydrin giving rise to highly reactive aminochlorohydrin and azetidinium groups; part remains intact and renders the product cationic and soluble.

[0027] The reactive groups on PAE may react with the cellulose on the one hand, and with the amine groups of PVAm on the other hand. Thus, the two polymers crosslink to form a three-dimensional network with the cellulose fibers in the substrate. After forming the cationic three-dimensional network on its surface, the substrate can absorb and release positive charged quaternary ions efficiently. The substrate surface no longer neutralizes the charge on the quaternary compounds and helps in efficient release of quaternary compounds for sanitizing and disinfectant applications. The three-dimensional network will help by not neutralizing the positive quaternary ions and will also help in the repelling the cationic ions, resulting in better release of quaternaries for sanitizing and disinfectant applications. There is no significant change in the physical properties of the nonwoven web.

[0028] The nonwoven fabric forming the substrate can be a wetlaid or spunlace product.

[0029] Preferred quaternary ammonium compounds include but are not limited to alkyl didecyl dimethyl ammonium chloride, benzalkonium chloride, benzethonium chloride, benzyldimethylstearylammonium chloride, cetalkonium chloride, cetrimide, cetylpyridinium chloride, cetyltrimethylammonium bromide, dialkyl dimethyl ammonium chloride, dihydrotallow dimethyl ammonium chloride, ditallowdimethylammomium chloride, N-alkyl dimethyl ethylbenzyl ammonium chloride, and N-alkyl dimethylbenzyl ammonium chloride. Examples of other useful antimicrobial agents are alcohols, halogenated diphenyl ethers, phenolic compounds, phenoxy propanol, benzyl alcohol and chlorhexidine hydrochloride.

[0030] A preferred method of surface treatment is by blending the two components in an aqueous solution at room temperature and applying to the nonwoven substrate by a dip and squeeze coating technique such as a size-press to control the addition level, and subsequently drying the substrate to remove substantially all of the water. Preferable ratios of PVAm to PAE are 8:1, 4:1 and 3:1.

[0031] According to a further aspect of the invention, the PVAm/PAE hydrogel complex can be further functionalized with silver nanoparticles to render the substrate antimicrobial. Further functionalization can be also be achieved due to the reactive nature of the primary amine groups.

[0032] A recommended treatment level is in the range of 1 to 2% added weight on the final product to optimize performance in terms of quaternary compound release improvement, ease of coating application and minimizing raw material cost. The treated level could be from 1% to 100% of the weight of the final product depending on the substrate application.

[0033] FIG. 1 depicts the three dimensional network comprising the two polymers which are cross-linked together with a small section of fiber. When the nonwoven web is passed through the polymer solution of poly(vinylamine) and poly(amideamine-epichlorohydrin) which was already in the cross-linked state, the squeezing action of the size press enhances the impregration of the polymer between the hydroentangled fibers. The polymer chains of the poly(vinylamine) and poly(amideamine-epichlorohydrin) encapsulate the fiber surface and are crosslinked three-dimensionally with each other due to the presence of amine groups. The FIGURE shows only a small portion of the web for clarity. However, the nonwoven web is completely covered with and intertwined with the poly(vinylamine) and poly(amideamine-epichlorohydrin) chains, which do not leach out even after storing the nonwoven web in quat solution for 8 hours.

EXAMPLES

[0034] The following non-limiting examples further illustrate the invention.

Example 1

[0035] An untreated 70 gsm nonwoven substrate was chosen which was made by hydro entangling 17 gsm polypropylene spunbond from Avgol and 53 gsm wood pulp—Grande Prairie (ECF—Elemental Chlorine Free) Northern Bleached Softwood pulp from Weyerhaeuser. The untreated substrate was treated with Kymene™ (Solenis) and Lupamin® 9095 (BASF) in a 1:4 ratio. Wipes prepared from the treated substrate were size pressed with a solution of Lupamin® (50 ml), Kymene™ (13 ml), water (1032 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (5 ml). The treated wipes were then dried using hot plate at 105° C. Both treated and untreated wipes were then tested to determine the quat release efficiency. A control quat solution of 800 ppm was made and added 4 times the weight of the dry untreated and treated wipes. The quat release efficiency was then titrated after 48 hours by squeezing 10 ml of quat solution from untreated and treated wipes. As shown in Table 1, the treated wipe showed 100% quat release efficiency after 48 hours as against untreated wipe which showed only 21% quat release efficiency. This result proves that this treatment can prevent the quat depletion over a period of time while maintaining a sufficient quat level for efficient disinfecting results.

TABLE-US-00001 TABLE 1 Sample Starting Quat Expressed after % Name ppm 48 hours Expressed Untreated 800 170 21 Treated 800 800 100

Example 2

[0036] In Example 2, 70 gsm wipes were prepared (Untreated) from substrate made by wet laid technology using 17 gsm polypropylene spunbond from Avgol and 53 gsm wood pulp—Grande Prairie (ECF—Elemental Chlorine Free) Northern Bleached Softwood pulp from Weyerhaeuser. The untreated wipe was treated with Kymene™ (from Solenis) and Lupamin® 9095 (from BASF) in 1:8 ratio. Wipes were size pressed with a solution of Lupamin® (100 ml), Kymene™ (13 ml), water (982 ml), with and without 5.5 ml of blue pigment (from Polysperse Corporation), and the pH of the solution was maintained at 10 by adding 25% NaOH (5 ml). The wipes were then dried using hot plate at 105° C. All treated, color treated and untreated wipes were then tested to determine the quat release efficiency. A control quat solution of 800 ppm was made and added 4 times the weight of the dry untreated, treated, and color treated wipes. The quat release efficiency was then titrated after 48 hours by squeezing 10 ml of quat solution from untreated, treated, and color treated wipes. As shown in Table 2, both the treated and color treated wipe showed 100% quat release efficiency after 48 hours as against untreated wipe which showed only 21% quat release efficiency. The result proves that this treatment can prevent the quat depletion over a period of time while maintaining a sufficient quat level for efficient disinfectant results.

TABLE-US-00002 TABLE 2 Expressed after 48 Sample Name Starting Quat ppm hours % Expressed Untreated 800 170 21 Treated 800 800 100 Color Treated 800 800 100

Example 3

[0037] In Example 3, 70 gsm wipes were prepared (Untreated) from substrate made by wet laid technology using 17 gsm polypropylene spunbond from Avgol and 53 gsm wood pulp—Grande Prairie (ECF—Elemental Chlorine Free) Northern Bleached Softwood pulp from Weyerhaeuser. The untreated wipes were sized pressed at different polymer concentrations using Kymene™ (from Solenis) and Lupamin® 9095 (from BASF) in 1:3 ratio. The pH of the treatment solution was maintained at pH 10 by adding 25% NaOH solution.

[0038] Treated A (10%)—The wipe was size pressed with a solution of Lupamin® (75 ml), Kymene™ (25 ml), water (900 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (5 ml).

[0039] Treated B (20%)—The wipe was size pressed with a solution of Lupamin® (150 ml), Kymene™ (50 ml), water (800 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (7 ml).

[0040] Treated C (30%)—The wipe was size pressed with a solution of Lupamin® (225 ml), Kymene™ (75 ml), water (700 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (12 ml).

[0041] The wipes were then dried using hot plate at 105° C. All treated and untreated wipes were tested to determine the quat release efficiency. A control quat solution of 550 ppm was made and tested with different treated and untreated wipes. 2 wipes approximately weighing 28 gm of each untreated and treated wipes were put in 2 liters of quat solution. After 15 min and 16 hrs, the wipes were taken out from the quat solution and excess solution was squeezed from the wipes. The wipes were then squeezed again for expressed solution (10 ml) in the titration container to determine the quat release efficiency. After 16 hrs, wipes were also tested to determine the quat depletion in the beaker due to the wipes. As shown in Table 3, the untreated wipe showed only 40% quat release efficiency as against treated wipes which were above 90% after 15 min. All the treated wipes showed 100% quat release efficiency after 16 hrs whereas untreated wipe showed only 45% quat release efficiency. The percent quat level in the beaker loaded with treated wipes after 16 hrs showed no decrease in the quat level against the untreated wipe.

TABLE-US-00003 TABLE 3 % % Expressed Expressed Expressed % quat Expressed Expressed ppm from quat from ppm from level in ppm from quat from Quat wipe after wipe after beaker after beaker after wipe after wipe after Sample ID ppm 15 min 15 min 16 hrs 16 hrs 16 hrs 16 hrs Untreated 550 220  40 270  49 250  45 Treated-A 550 520  95 550 100 550 100 Treated-B 550 530  96 550 100 550 100 Treated-C 550 550 100 550 100 550 100

Example 4

[0042] In Example 4, 70 gsm wipes were prepared (Untreated) from substrate made by wet laid technology using 17 gsm polypropylene spunbond from Avgol and 53 gsm wood pulp—Grande Prairie (ECF—Elemental Chlorine Free) Northern Bleached Softwood pulp from Weyerhaeuser. The untreated wipes were size pressed at different following polymers concentrations with the Kymene™ (from Solenis) and Lupamin® 9095 (from BASF) in 1:3 ratio. The pH of the treatment solution was maintained at pH 10 by adding 25% NaOH solution.

[0043] Treated A (10%)—The wipe was size pressed with a solution of Lupamin® (75 ml), Kymene™ (25 ml), water (900 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (5 ml).

[0044] Treated B (20%)—The wipe was size pressed with a solution of Lupamin® (150 ml), Kymene™ (50 ml), water (800 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (7 ml).

[0045] Treated C (30%)—The wipe was size pressed with a solution of Lupamin® (225 ml), Kymene™ (75 ml), water (700 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (12 ml).

[0046] The wipes were then dried using hot plate at 105° C. All treated and untreated wipes were tested to determine the quat release efficiency. Quat solutions of 3320 ppm to 3440 ppm were made and tested with different treated and untreated wipes. These quat solutions were used to lotionize the wipes and were added at 4 times the weight of the dry treated and untreated wipes. The quat release efficiency was then titrated after 72 hours by squeezing 10 ml of quat solution from untreated and treated wipes. As shown in Table 4, the treated wipes (B and C) showed 100% quat release efficiency after 72 hours against untreated wipe which showed only 32-34% % quat release efficiency. This result proves that this treatment can prevent the quat depletion after 72 hours while maintaining sufficient quat levels for efficient disinfecting results.

TABLE-US-00004 TABLE 4 Starting Quat Expressed ppm from % Expressed quat from Sample ID Conc (ppm) wipe after 72 hours wipe after 72 hrs Untreated 3440 1090 32 Treated-A 3440 3000 87 Untreated 3250 1090 34 Treated-B 3250 3320 102 Untreated 3220 1045 32 Treated-C 3220 3350 104

Example 5

[0047] In Example 5, 70 gsm wipes were prepared (Untreated) from substrate made by wet laid technology using 17 gsm polypropylene spunbond from Avgol and 53 gsm wood pulp—Grande Prairie (ECF—Elemental Chlorine Free) Northern Bleached Softwood pulp from Weyerhaeuser. The untreated wipes were sized pressed at varying polymers concentrations with Kymene™ (from Solenis) and Lupamin® 9095 (from BASF) in 1:3 ratio. The pH of the treatment solution was maintained at pH 10 by adding 25% NaOH solution. Treated (20%)—wipe was size pressed with a solution of Lupamin® (150 ml), Kymene™ (50 ml), water (800 ml), and the pH of the solution was maintained at 10 by adding 25% NaOH (7 ml). The treated wipe was then dried using hot plate at 105 degree C. All treated and untreated wipes were then tested to determine the quat release efficiency. A control quat solution of 400 ppm was made and tested with different treated and untreated wipes. 10 wipes each, approximately weighing 14 gm, of untreated and treated wipes were put in 10 liters of quat solution. After every hour over a period of total 5 hours, 2 wipes were taken out from the quat solution and excess solution was squeezed from the wipes. The wipes were then squeezed again for expressed solution (10 ml) in the titration container to determine the quat release efficiency. Those wipes were kept aside and not put again in the quat solution. At the same time, after every hour, wipes were also tested to determine the quat depletion in the beaker due to the wipes. As shown in Table 5, after 5 hours, the expressed quat of treated wipe was significantly higher than untreated wipes, maintaining a sufficient level of quat for disinfecting purposes.

TABLE-US-00005 TABLE 5 Starting Expressed Expressed Sample Quat ppm from ppm from Name Hours ppm wipe beaker Untreated 1 400 210 250 2 400 230 250 3 400 230 250 4 400 210 330 5 400 190 300 Treated 1 400 390 330 2 400 450 380 3 400 420 360 4 400 320 400 5 400 300 310