Color changing matrix as wear indicator

• US 5,906,834 A
• Filed: 10/09/1996
• Issued: 05/25/1999
• Est. Priority Date: 06/15/1992
• Status: Expired due to Term

• Current Assignee: Gillette Company (The Procter & Gamble Company)
• Original Assignee: Gillette Company (The Procter & Gamble Company)
• Inventors: Tseng, Mingchih M.
• Primary Examiner(s): Achutamurthy, Ponnathapura
• Assistant Examiner(s): NELSON, BRETT L
• Application Number:
  US08/731,064
• Time in Patent Office: 958 Days
• Field of Search: 424/46, 424/401, 424/486, 424/487, 15/167.1, 15/159, 15/160, 15/104.93, 15/104.94
• US Class Current: 424/486
• CPC Class Codes: A46B 11/00 Brushes with reservoir or other means for applying substances, e.g. paints, pastes, water driven brush bodies A46B13/00; massage apparatus with liquid delivery A61H7/002, A61H2201/105; applying liquids or other fluent materials to surfaces by liquid carrying members in general, e.g. by pads B05C1/00, B05D1/28
• CPC Class Codes: A61K 2800/43 Pigments; Dyes
• CPC Class Codes: A61K 8/86 Polyethers
• CPC Class Codes: A61Q 11/00 Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses

Abstract

A sustained-release matrix for dental application includes either an anti-microbial agent or a colorant that is released from the matrix when the matrix contacts water. The preferred matrices include a water-soluble polymer and a water-insoluble support resin.

Claims

1. A color-changing matrix comprising two joined layers, an outer layer comprising a water-soluble polymer, a water-insoluble polymer and a first colorant, and an inner layer comprising a water-insoluble polymer and a second colorant different from said first colorant.

2. The color-changing matrix of claim 1 wherein the water-soluble polymer comprises polyethylene oxide.

3. The color-changing matrix of claim 2 wherein the polyethylene oxide has a molecular weight of 100,000 to 5,000,000.

4. The color-changing matrix of claim 3 wherein the polyethylene oxide is a blend comprising 60 parts of coagulant grade polyethylene oxide and 40 parts of polyethylene oxide of molecular weight 300,000.

5. The color-changing matrix of claim 2, 3 or 4 wherein the water-insoluble polymer in each layer is selected from the group consisting of polystyrene, polyurethane, ethylene vinyl acetate, polyethylene, styrene/rubber and ethylene/propylene.

6. The color-changing matrix of claim 1 wherein the inner layer additionally comprises a water-soluble polymer.

7. The color-changing matrix of claim 6 wherein the water-soluble polymer in each layer comprises polyethylene oxide.

8. The color-changing matrix of claim 7 wherein the polyethylene oxide has a molecular weight of 100,000 to 5,000,000.

9. The color-changing matrix of claim 8 wherein the polyethylene oxide is a blend comprising 60 parts of coagulant grade polyethylene oxide and 40 parts of polyethylene oxide of molecular weight 300,000.

10. The color-changing matrix of claim 7, 8 or 9 wherein the water-insoluble polymer in each layer is selected from the group consisting of polystyrene, polyurethane, ethylene vinyl acetate, polyethylene, styrene/rubber and ethylene/propylene.

11. The color-changing matrix of claim 1, 3, 6 or 8 wherein said two joined layers are coextruded.

12. The color-changing matrix of claim 1, 3, 6 or 8 wherein said outer layer is adapted to dissolve away through repeated contact with water to expose said inner layer.

13. A method of indicating wear comprising

providing a color-changing matrix comprising two joined layers, an outer layer comprising a water-soluble polymer, a water-insoluble polymer and a first colorant, and an inner layer comprising a water-insoluble polymer and a second colorant different from said first colorant, and

repeatedly contacting said matrix with water to expose said inner layer.

14. The method of claim 13 wherein the water-soluble polymer comprises polyethylene oxide.

15. The method of claim 13 wherein the polyethylene oxide has a molecular weight of 100,000 to 5,000,000.

16. The method of claim 15 wherein the polyethylene oxide is a blend comprising 60 parts of coagulant grade polyethylene oxide and 40 parts of polyethylene oxide of molecular weight 300,000.

17. The method of claim 14, 15 or 16 wherein the water-insoluble polymer in each layer is selected from the group consisting of polystyrene, polyurethane, ethylene vinyl acetate, polyethylene, styrene/rubber and ethylene/propylene.

18. The method of claim 13 wherein the inner layer additionally comprises a water-soluble polymer.

19. The method of claim 18 wherein the water-soluble polymer in each layer comprises polyethylene oxide.

20. The method of claim 19 wherein the polyethylene oxide has a molecular weight of 100,000 to 5,000,000.

21. The method of claim 20 wherein the polyethylene oxide is a blend comprising 60 parts of coagulant grade polyethylene oxide and 40 parts of polyethylene oxide of molecular weight 300,000.

22. The method of claim 19, 20 or 21 wherein the water-insoluble polymer in each layer is selected from the group consisting of polystyrene, polyurethane, ethylene vinyl acetate, polyethylene, styrene/rubber and ethylene/propylene.

23. The method of claim 13, 15, 18 or 20 wherein said two joined layers are coextruded.

24. The method of claim 13, 15, 18 or 20 wherein said outer layer is adapted to dissolve away through repeated contact with water to expose said inner layer.