WO2005090680A1

WO2005090680A1 - Tissue paper assembly

Info

Publication number: WO2005090680A1
Application number: PCT/GB2005/001163
Authority: WO
Inventors: Jonathan Peter Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-03-20
Filing date: 2005-03-21
Publication date: 2005-09-29
Anticipated expiration: 2006-09-20
Also published as: GB0406360D0; GB2412084B; GB2412084A

Abstract

A paper assembly (10) for use as disposable cleaning tissue comprises a first paper member (12) and a second paper member (14), the first paper member (12) having a lower basis weight and a higher water absorbency than the second paper member (14).

Description

TISSUE PAPER ASSEMBLY

The present invention relates to paper assemblies, particularly but not exclusively paper assemblies for use as disposable cleaning tissues.

Conventionally, disposable cleaning tissues such as toilet tissues comprise single or multiple ply tissue which is relatively soft and absorbent. Environmental concerns require that the toilet tissue is rapidly biodegradable, and the wet strength of the toilet tissue must be relatively low so that the tissue disintegrates rapidly in the sewage system and does not block the sewers. While softness is desired by the user, the accompanying characteristics of high liquid absorption and low strength can be a disadvantage since in certain circumstances the tissue may disintegrate in use. To prevent the risk of this occurring, the user often uses more toilet tissue than necessary. This degree of overuse, even though relatively small for each user, has a significant impact in global terms for paper and forestry resources and sewage systems.

A number of test methods are available for testing the water absorbency of paper. In this specification, water absorbency figures are quoted with reference to TAPPI test method T432, in which a rate of absorbency is derived from the time taken for a finite amount of water to be completely absorbed by the paper being tested. According to the present invention there is provided a paper assembly for use as disposable cleaning tissue, the assembly comprising a first paper member and a second paper member, the first paper member having a lower basis weight and a higher water absorbency than the second paper member. Preferably, the first member has a basis weight of less than 20 g/m². Preferably, the first member has a water absorbency measured by TAPPI test method T432 of at least 17 millilitres per second, and more preferably of at least 167 millilitres per second. Preferably, the second member has a basis weight of at least 20 g/m², and more preferably has a basis weight in the range 20 to 50 g/m², and optimally of approximately 25 g/m².

Preferably, the second member has a water absorbency of less than 17 millilitres per second, and more preferably of less than 5 millilitres per second.

Preferably, the wet strength of the first member is less than or equal to 10% of the dry strength of the first member, and more preferably is less than or equal to 1 % of the dry strength of the first member.

Preferably, the wet strength of the second member is more than 10% of the dry strength of the second member. Preferably, the first member is substantially free of any plastics materials. Preferably, the second member is substantially free of any plastics materials. Preferably, the assembly is substantially free of any plastics materials. Preferably, the first member is formed of cellulose fibres and the second member may also be formed of cellulose fibres. Preferably the first member fibres are shorter in average length than the second member fibres. Preferably, the first member fibres have a lower degree of inter-fibre bonding than the second member fibres. Preferably, the average length of the first member fibres is less than 2mm, and more preferably is less than 1mm. Preferably, the average length of the second member fibres is more than 2mm, and more preferably is between 2 and 8mm. Preferably, more than 50% by weight of the first member fibres are formed by mechanical pulping, and more preferably are formed by chemi- thermomechanical pulping. Preferably, more than 50% by weight of the second member fibres are formed by chemical pulping.

Preferably, more than 50% by weight of the first member fibres are derived from the well-known group referred to as hardwoods. Preferably, more than 50% by weight of the second member fibres are derived from the well-known group referred to as softwoods.

Preferably, the first member is sheet-like in form. The first member may have a face, and more preferably may have a pair of oppositely directed faces. Preferably, the second member is sheet-like in form. The second member may have a face, and more preferably may have a pair of oppositely directed faces. Preferably, the assembly is arranged so that the or one face of the first member lies substantially adjacent to the or one face of the second member.

The assembly may include attachment means for attaching the first and second members together. The attachment means may be arranged to permit selective attachment of the first and second members together. The attachment means may comprise adhesive, which may be applied to a portion or portions of the or the one face or faces. Alternatively or in addition, the attachment means may comprise a region or regions in which the first and second members are physically bonded together. The physical attachment means may be formed by a process such as heating, crimping, embossing, spiking, needling, perforating, or any other suitable process.

The first member and the second member may be the same size. Alternatively, the first member ^'may be smaller than the second member, and may be located adjacent to a central portion of the one face of the second member. In another embodiment, the second member may be smaller than the first member, and the second member may be located adjacent to a central portion of the one face of the first member. The first member may have a different appearance from the second member. The first member may be coloured differently, and/or have different markings, and/or different embossed patterns.

The present invention further provides a first paper member as set out above for use in a paper assembly as described in the preceding paragraphs.

The present invention still further provides a second paper member as set out above for use in a paper assembly as described in the preceding paragraphs.

The invention also provides a dispensing assembly, the dispensing assembly comprising a plurality of paper assemblies as described above.

Each paper assembly may be provided as a separate unit, and each paper assembly may be folded and interleaved with a successive paper assembly to aid removal by a user.

Alternatively, the paper assemblies may be provided in a continuous form such as a sheet or roll. Each assembly may be separable from a successive assembly by lines of weakness, which may comprise perforations.

Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:-

Fig. 1 is a perspective view of a paper assembly according to the invention; Fig. 2 is a perspective view of a dispensing assembly according to the invention; Fig. 3 is a perspective view of another dispensing assembly; Fig. 4 is a cross-sectional view from the side of a part of the dispensing assembly of Fig. 3; Fig. 5 is a perspective view of another paper assembly; Fig. 6 is a perspective view of another paper assembly; Fig. 7 is a perspective view of another paper assembly; and Fig. 8 is a schematic cross-sectional view from the side of another dispensing assembly.

Fig. 1 shows a paper assembly 10 comprising a first paper member 12 and a second paper member 14. Each paper member 12, 14 is in the form of a sheet having a pair of oppositely directed faces, the first paper member 12 having an upper face 32 and a lower face 30 and the second paper member 14 having an upper face 34 and a lower face 36. The paper assembly 10 is arranged so that the lower face 30 of the first member 12 lies substantially adjacent to the upper face 34 of the second member 14.

The first paper member 12 and the second paper member 14 each comprise a plurality of cellulose fibres, and have different characteristics which are indicated generally in Table 1 below.

Table 1

Table 1 shows in general terms the characteristics of the first and second paper members 12, 14 in accordance with the invention. In accordance with these characteristics, the first paper member 12 is a sheet of relatively soft tissue paper with relatively high water absorbency and relatively low wet strength. Such a paper product can be formed from pulp formed by mechanical pulping, which is known to produce a softer, weaker paper since the mechanical processing action breaks the cellulose fibres, resulting in a paper which is formed of relatively short fibres. Thus, for example, the average length of the fibres of the first member 12 is less than 2mm.

Additionally, the process of mechanical pulping can include heat treatment, and chemical treatment with sodium sulphite to produce chemi- thermo-mechanical pulp having relatively short, relatively soft fibres.

In contrast, the second paper member 14 is a relatively hard, relatively strong paper having relatively low water absorbency and relatively high wet strength. Such a paper product can be formed from pulp formed by chemical pulping, which is known to produce a harder, stronger paper since the process of chemical pulping results in longer fibres as the fibres are not broken during mechanical processing. The longer fibres result in a higher strength of paper. Thus, for example, the average fibre length of the fibres of the second member 14 is more than 2mm.

The characteristics of the finished paper also depend upon the material from which the fibres are derived. For example, fibres derived from hardwoods generally produce a paper which is less strong than fibres derived from softwoods. Examples of hardwoods are broad leaved or deciduous trees such as birch, eucalyptus, aspen and acacia. Example of softwoods are evergreens and conifers such as pine and spruce.

The characteristics of the first and second paper members 12, 14 shown in Table 1 can thus be obtained by careful selection of the process type and the fibre type. In general, the relatively soft, relatively weak characteristics of the first member 12 can be produced by including more than 50% by weight of mechanically pulped fibres and more than 50% by weight of fibres derived from hardwoods. The second paper member 14 characteristics are produced by including more than 50% by weight of fibres formed by chemical pulping and more than 50% by weight of fibres derived from softwoods. In a more specific example, a paper assembly comprises a first member 12 having a basis weight of less than 20g per m², a water absorbency measured by TAPPI test method T432 of at least 167 millilitres per second, a wet strength of less than 1% of the dry strength of the first member, and an average fibre length of less than 1 mm. The second member 14 has a basis weight in the range 20 - 50g/m² and optimally of approximately 25g per m², a water absorbency measured by TAPPI test method T432 of less than 5 millilitres per second, a wet strength of more than 10% of the dry strength of the second member and an average fibre length of between 2 and 8mm.

Fig. 2 shows a dispensing assembly 20 comprising a plurality of paper assemblies 10 as described previously. The paper assemblies 10 are provided in a continuous form, which in the example shown in Fig. 2 is in a form of a roll, with each successive paper assembly 10 separated by a line of weakness in the form of perforations 16 from the succeeding assembly 10. Each paper assembly 10 can be separated from the succeeding assembly 10 by tearing along the line of perforations 16 in a conventional manner.

Fig. 3 shows another dispensing assembly 120 comprising a plurality of paper assemblies 110. Each paper assembly 110 includes a first member 12 and a second member 14 as described previously and is separated from a successive paper member 110 by a line of perforations 16. Each paper assembly 110 includes attachment means in the form of a plurality of needled punctures 118. The needled punctures 118 are arranged in the example shown in Fig. 3 in a pair of rows, one row located towards each of the longer edges of the paper assembly or assemblies 110. Fig. 4 shows a cross-section detail through one of the needled punctures 118. The needled punctures 118 are simply formed by a needle passing through the first member 12 and the second member 14 together, so that material from the first member 12 is forced to project into, and thereby interlock with the second member 14. The process of needling forms a simple mechanical interlock between the first member 12 and the second member 14. The first paper member 12 is easily separable from the second paper member 14 by a user if required. Fig. 5 shows another paper assembly 210, comprising a first paper member 12 and a second paper member 14 and attachment means in the form of adhesive which is applied to a portion or portions of the inward facing faces 30, 34 of the first member 12 and second member 14 respectively. In Fig. 5, the portions to which adhesive is applied are shown by hatched areas 222 which are located along the longer edges of the paper assembly 210.

Fig. 6 shows another paper assembly 310, in which the first paper member 12 is smaller than the second paper member 14. The first paper member 12 is located adjacent to a central portion of the upper face 34 of the second member 14. The paper assembly 310 thus provides a relatively large, strong second paper member 14 having relatively low water absorption, with a relatively small, relatively soft first paper member 12 having relatively high water absorption. Fig. 7 shows another paper assembly 410 similar to that of Fig. 6, except that the paper assembly 410 of Fig. 7 has a larger, less strong first paper assembly 12 having relatively high water absorption with a relatively small, relatively strong second paper member 14 having relatively low water absorption. The second paper member 14 acts as a reinforcing strip, located adjacent to a central portion of the lower face 30 of the first member 12 as indicated by dotted lines in Fig. 7. Fig. 8 shows another dispensing assembly 520 comprising a plurality of paper assemblies 10. Each paper assembly 10 is provided as a separate unit, and is folded and interleaved with a successive paper assembly 10. The dispensing assembly 520 comprises a container 524 in which the interleaved paper assemblies 10 are located. The container 524 defines an opening 526 through which a user can remove the paper assemblies 10. As each paper assembly 10 is removed, the interleaving lifts a part of the successive paper member 10 to aid removal by a user. Various modifications may be made without departing from the scope of the invention. The first paper member and the second paper member could include fibres derived from any suitable source and by any suitable processing means. The first and second members may be coloured differently and have different markings, and/or have different embossed patterns. The first and second members could comprise other materials such as fillers, perfumes, or fragrances. The first and second members could be of any suitable size and may be located adjacent to each other in any suitable way. Any suitable attachment means could be used such as heating, crimping, embossing, spiking, perforating or any other suitable process. The dispensing assembly could include paper assemblies in any suitable arrangement.

A paper assembly could include a plurality of first and/or second paper members. For example, a paper assembly could include several first paper members reinforced by one second paper member.

The paper assemblies could be suitable for any convenient use, such as toilet tissue, disposable handkerchiefs, skin cleansing wipes, kitchen towels, cleaning cloths and table paperware.

There is thus provided a paper assembly suitable for disposable cleaning purposes and in particular for use as toilet tissue. The requirements that toilet paper must meet are many, varied, and often conflicting. Toilet paper must be easily biodegradable. Reinforcement by plastics material, such as polymer film can lead to problems in the sewage system, since such film does not degrade sufficiently easily or rapidly. It is preferred therefore, not to use such plastics material in toilet tissue. A user requires the toilet tissue to be soft and absorbent, but not to fall apart in use. Providing such a single type of paper to meet these varied requirements inevitably results in compromise in terms of the characteristics of the paper. The applicant has realised that the provision of a paper assembly comprising a first paper member and a second paper member of differing characteristics allows the user's requirements of softness, absorptivity, and strength to be better met. In such an assembly, the first paper member can be softer and more absorbent than would otherwise be possible, since the first paper member is supported and reinforced by the harder, stronger, less absorbent second paper member. Such a paper assembly provides the user with the characteristics of softness and absorption which he desires with the confidence that the assembly will not disintegrate in use, thus preventing the overuse of toilet paper.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A paper assembly for use as disposable cleaning tissue, the assembly comprising a first paper member and a second paper member, the first paper member having a lower basis weight and a higher water absorbency than the second paper member.

2. A paper assembly according to claim 1 , in which the first member has a basis weight of less than 20 g/m².

3. A paper assembly according to claims 1 or 2, in which the first member has a water absorbency measured by TAPPI test method T432 of at least 17 millilitres per second.

4. A paper assembly according to claim 3, in which the first member has a water absorbency measured by TAPPI test method T432 of at least 167 millilitres per second.

5. A paper assembly according to any of the preceding claims, in which the second member has a basis weight of at least 20 g/m².

6. A paper assembly according to claim 5, in which the second member has a basis weight in the range 20 to 50 g/m².

7. A paper assembly according to claims 5 or 6, in which the second member has a basis weight of approximately 25 g/m².

8. A paper assembly according to any of the preceding claims, in which the second member has a water absorbency of less than 17 millilitres per second.

9. A paper assembly according to claim 8, in which the second member has a water absorbency of less than 5 millilitres per second.

10. A paper assembly according to any of the preceding claims, in which the wet strength of the first member is less than or equal to 10% of the dry strength of the first member.

11. A paper assembly according to claim 10, the wet strength of the first member is less than or equal to 1 % of the dry strength of the first member.

12. A paper assembly according to any of the preceding claims, in which the wet strength of the second member is more than 10% of the dry strength of the second member.

13. A paper assembly according to any of the preceding claims, in which the first member is substantially free of any plastics materials.

14. A paper assembly according to any of the preceding claims, in which the second member is substantially free of any plastics materials.

15. A paper assembly according to claim 14 when dependent on claim 13, in which the assembly is substantially free of any plastics materials.

16. A paper assembly according to any of the preceding claims, in which the first member is formed of cellulose fibres.

17. A paper assembly according to claim 16, in which the average length of the first member fibres is less than 2mm.

18. A paper assembly according to claim 17, in which the average length of the first member fibres is less than 1 mm.

19. A paper assembly according to any of claims 16 to 18, in which second member is also formed of cellulose fibres.

20. A paper assembly according to claim 19, in which the first member fibres are shorter in average length than the second member fibres.

21. A paper assembly according to claim 20, in which the average length of the second member fibres is more than 2mm.

22. A paper assembly according to claim 21 , in which the average length of the second member fibres is between 2 and 8mm.

23. A paper assembly according to any of claims 19 to 22, in which the first member fibres have a lower degree of inter-fibre bonding than the second member fibres.

24. A paper assembly according to any of claims 16 to 23, in which more than 50% by weight of the first member fibres are formed by mechanical pulping.

25. A paper assembly according to claim 24, in which more than 50% by weight of the first member fibres are formed by chemi-thermomechanical pulping.

26. A paper assembly according to claim 19 and any claim dependent thereon, in which more than 50% by weight of the second member fibres are formed by chemical pulping.

27. A paper assembly according to any of claims 16 to 26, in which more than 50% by weight of the first member fibres are derived from the well-known group referred to as hardwoods.

28. A paper assembly according to claim 19 and any claim dependent thereon, in which more than 50% by weight of the second member fibres are derived from the well-known group referred to as softwoods.

29. A paper assembly according to any of the preceding claims, in which the first member is sheet-like in form, having a pair of oppositely directed faces, and the second member is sheet-like in form, having a pair of oppositely directed faces.

30. A paper assembly according to claim 29, in which the assembly is arranged so that one face of the first member lies substantially adjacent to one face of the second member.

31. A paper assembly according to any of the preceding claims, in which the assembly includes attachment means for attaching the first and second members together.

32. A paper assembly according to claim 31 , in which the attachment means are arranged to permit selective attachment of the first and second members together.

33. A paper assembly according to claims 31 or 32,- in which the attachment means comprise adhesive.

34. A paper assembly according to claim 33, in which the adhesive is applied to a portion or portions of the or the one face or faces.

35. A paper assembly according to any of claims 31 to 34, in which the attachment means comprises a region or regions in which the first and second members are physically bonded together.

36. A paper assembly according to claim 35, in which the physical attachment means is formed by a process such as heating, crimping, embossing, spiking, needling, perforating, or any other suitable process.

37. A paper assembly according to any of the preceding claims, in which the first member and the second member are the same size.

38. A paper assembly according to any of claims 1 to 36, in which the first member is smaller than the second member.

39. A paper assembly according to claim 38 when dependent on claim 30 and any claim dependent thereon, in which the first member is located adjacent to a central portion of the one face of the second member.

40. A paper assembly according to any of claims 1 to 36, in which the second member is smaller than the first member and the second member is located adjacent to a central portion of the one face of the first member.

41. A paper assembly according to any of the preceding claims, in which the first member has a different appearance from the second member.

42. A paper assembly according to claim 41 , in which the first member is coloured differently, and/or has different markings, and/or different embossed patterns.

43. A first paper member for use in a paper assembly according to any of the preceding claims.

44. A second paper member for use in a paper assembly according to any of claims 1 to 42.

45. A dispensing assembly, the dispensing assembly comprising a plurality of paper assemblies according to any of claims 1 to 42.

46. A dispensing assembly according to claim 45, in which each paper assembly is provided as a separate unit.

47. A dispensing assembly according to claim 46, in which each paper assembly is folded and interleaved with a successive paper assembly to aid removal by a user.

48. A dispensing assembly according to claim 45, in which the paper assemblies are provided in a continuous form such as a sheet or roll.

49. A dispensing assembly according to claim 48, in which each assembly is separable from a successive assembly by lines of weakness.

50. A dispensing assembly according to claim 49, in which the lines of weakness comprise perforations.

51. A paper assembly substantially as hereinbefore described and with reference to the accompanying drawings.

52. A first paper member substantially as hereinbefore described and with reference to the accompanying drawings.

53. A second paper member substantially as hereinbefore described and with reference to the accompanying drawings.

54. A dispensing assembly substantially as hereinbefore described and with reference to the accompanying drawings.

55. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.