Automatic machine laundering of fabrics

• US 20050124521A1
• Filed: 12/03/2004
• Published: 06/09/2005
• Est. Priority Date: 12/03/2003
• Status: Active Grant

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Aouad, Yousef Georges, Sadlowski, Eugene Steven, Becks, Vincent John, Wevers, Jean
• Granted Patent: US 7,445,643 B2
• Time in Patent Office: Days
• US Class Current: 510/295
• CPC Class Codes: D06F 35/006 for washing or rinsing only
• CPC Class Codes: D06F 39/024 mounted on the agitator or the rotating drum; Free body dispensers

Abstract

The invention provides a method of laundering fabrics in an automatic washing machine having a drum wherein the automatic washing machine is operated so as to cause it to run through at least one wash cycle and at least one rinse cycle. Such a method comprises: (a) during the at least one wash cycle forming in the drum an aqueous washing liquor containing a detersive surfactant component and a detergent builder component, the aqueous wash liquor having pH above about 7; (b) contacting fabrics to be laundered with the aqueous wash liquor in the drum; (c) during the rinse cycle forming in the drum an aqueous rinse liquor and contacting the fabrics with the rinse liquor; (d) adding to the rinse liquor sufficient acid source to bring the pH of the rinse liquor in the range of from about 4 to about 7, preferably from about 4.5 to about 6.5. The use of this lowered pH in the rinse liquor gives a variety of cleaning benefits, and preferably fabric care benefits in combination with rinse additive, in the context of an automatic washing process. The invention also provides particular systems for application of the acid source to the rinse liquor.

Claims

1. A method of laundering fabrics in an automatic washing machine having a drum, wherein the automatic washing machine is operated so as to cause it to run through at least one wash cycle and at least one rinse cycle, which method comprises:

(a) during the at least one wash cycle forming in the drum an aqueous washing liquor containing a detersive surfactant component and a detergent builder component, the aqueous wash liquor having pH above about 7;

(b) contacting fabrics to be laundered with the aqueous wash liquor in the drum;

(c) during the rinse cycle, forming in the drum an aqueous rinse liquor and contacting the fabrics with said rinse liquor; and

(d) adding to the rinse liquor sufficient acid source to bring the pH of the rinse liquor into the range of from about 4 to about 7.

2. A method according to claim 1 which comprises contacting the laundry with the aqueous wash liquor for from about 1 to about 50 mins, removing from about 50% to 99% of the aqueous wash liquor from the drum during a spin cycle carried out between the wash cycle and the rinse cycle, and contacting the fabrics with the aqueous rinse liquor for from about 1 to 20 minutes.

3. A method according to claim 1 which also comprises adding to the rinse liquor a laundry rinse additive material.

4. A method according to claim 3 in which the rinse additive is a perfume or pro-perfume.

5. A method according to claim 3 in which the rinse additive is a chelant.

6. A method according to claim 3 in which the rinse additive is a fabric brightening agent.

7. A method according to claim 3 in which the rinse additive is a fabric care benefit agent selected from softness, feel and wrinkle modifiers.

8. A method according to claim 3 in which the rinse additive is a soil release agent or soil repellent agent.

9. A method according to claim 3 in which the rinse additive is a bleach or bleach catalyst.

10. A method according to claim 1 in which the fabric laundered comprises fabric stained with stains selected from bleachable stains, greasy stains and stains susceptible to removal by enzymes.

11. A method according to claim 1 in which the fabrics laundered comprise dyed fabrics.

12. A method according to claim 1 in which the maximum temperature of the aqueous wash liquor and the aqueous rinse liquor is not more than about 60°

C.

13. A method according to claim 1 in which the hardness of the water used to form the aqueous wash liquor and the aqueous rinse liquor is at least about 100 ppm as CaCO₃.

14. A method according to claim 1 in which the aqueous wash liquor is provided by adding to water a detergent composition in the form of a liquid and wherein the pH of the aqueous wash liquor so provided is not more than about 10.

15. A method according to claim 1 in which the aqueous wash liquor is formed by adding to water a detergent composition comprising a surfactant selected from anionic, nonionic, cationic and amphoteric surfactants, preferably selected from linear alkyl benzene sulphonates, alkyl ethoxylates, amine oxides, alkyl quaternary ammonium salts and betaines.

16. A method according to claim 1 wherein said method further comprises:

(a) providing a unit dose package containing a laundry rinse additive material;

(b) inserting said additive-containing unit dose package into a rigid housing structure;

(c) at the beginning of the operation of the automatic washing machine positioning said housing structure, with said additive-containing unit dose package therein, within the drum of said automatic washing machine in a location which brings it into significant contact with the aqueous rinse liquor during the rinse cycle;

(d) running the automatic washing machine through a process comprising a spin cycle between the at least one wash cycle and the rinse cycle to thereby apply centrifugal force to said additive-containing unit dose package within said housing structure, said centrifugal force serving to activate the package opening means associated with said package or said housing structure or both, and to thereby open said package, release the contents thereof, and hold said contents within said rigid housing structure; and

thereafter

(e) removing the centrifugal force from said opened package by ending the spin cycle during operation of said automatic washing machine; and

thereafter

(f) allowing the laundry additive material within said rigid housing structure to pass by gravitational flow through apertures in said housing structure into the aqueous rinse liquor during the rinse cycle in the operation of said automatic washing machine.

17. A method according to claim 3 wherein said method further comprises:

(a) positioning a rigid housing structure within the washing machine in a fixed spatial relationship to said washing machine drum which housing structure comprises a base and an openable and closable lid for said base;

(b) placing within said housing structure with its lid open at the beginning of the laundering operation, a multi-compartmented insert containing within at least two different compartments thereof at least two different laundry additive materials of which one is to be added to the contents of the washing machine drum during the at least one wash cycle and one is to be added to the contents of the washing machine drum during the rinse cycle;

(c) closing the lid of said housing structure with said insert inside to thereby activate means associated with said rigid housing structure to open at least a first compartment of the multi-compartmented insert and to thereby permit dispensing of the material within said opened compartment into said washing machine drum; and

(d) running said automatic washing machine through its operational cycle, including a spin cycle between the at least one wash cycle and the rinse cycle to thereby activate means associated with said housing structure and/or with said multi-compartmented insert to open one or more additional compartments of said insert containing laundry additive material different from that in said previously opened first compartment, said opening of said additional compartments occurring after initiation of the spin cycle of said washing machine operation, and said means for opening said additional compartments being activated by the centrifugal force arising from the spin cycle;

said opening further permitting the dispensing of the material within said opened compartment(s) into said washing machine drum.

18. A system for providing sequential addition of wash additives and rinse additives to the wash and rinse cycles, respectively, of a fabric laundering operation carried out in a drum-containing automatic washing machine, which system comprises:

(a) a unit dose package comprising at least one compartment containing wash additive material comprising a detersive surfactant component and a detergent builder component, said wash additive material serving to provide aqueous wash liquor having a pH of above about 7; and

at least one additional compartment containing an acid source sufficient to bring the pH of rinse liquor formed during said rinse cycle to a pH of from about 4 to about 7;

(b) a rigid housing structure into which at least the rinse additive compartment(s) of said unit dose package can be inserted at the beginning of the laundering operation, said housing structure being positioned within the drum of said automatic washing machine in a location which brings it into significant contact with wash and rinse water during the laundering operation;

(c) means associated with said wash additive material compartment(s) of the unit dose package to open said wash additive compartment(s) and to thereby release the contents of said wash additive compartment(s) into the aqueous wash liquor in said drum;

(d) means associated with said housing structure or with said rinse additive compartment(s) of said unit dose package or with both to open said rinse additive compartment(s) and to thereby release the rinse additive contents thereof into said housing structure, said rinse additive compartment opening means being activated by centrifugal force applied to said rinse additive compartment(s) during the spin cycle occurring in the operation of said automatic washing machine; and

(e) means for transferring said rinse additive material from said housing structure into the aqueous rinse liquor formed in said washing machine drum during the rinse cycle of said fabric laundering operation.

19. A system according to claim 18 wherein said acid source is sufficient bring the pH of the rinse liquor to within the range of from about 4.5. to 6.5.