U.S. patent application number 11/661862 was filed with the patent office on 2007-11-15 for sheet product comprising at least two plies joined by gluing with non-uniform distribution of the glue.
This patent application is currently assigned to FABIO PERINI S.P.A.. Invention is credited to Mauro Gelli.
Application Number | 20070264461 11/661862 |
Document ID | / |
Family ID | 34956365 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070264461 |
Kind Code |
A1 |
Gelli; Mauro |
November 15, 2007 |
Sheet Product Comprising at Least Two Plies Joined by Gluing with
Non-Uniform Distribution of the Glue
Abstract
The sheet product, such as paper, wound in a roll, comprises at
least two plies (V1, V2) joined together by gluing, at least one of
which is embossed. The product has longitudinal bands or areas (1,
3) which are characterized by a different quantity of glue, with
more glue in proximity to the edges.
Inventors: |
Gelli; Mauro; (Lucca,
IT) |
Correspondence
Address: |
BREINER & BREINER, L.L.C.
P.O. BOX 19290
ALEXANDRIA
VA
22320-0290
US
|
Assignee: |
FABIO PERINI S.P.A.
LUCCA
IT
|
Family ID: |
34956365 |
Appl. No.: |
11/661862 |
Filed: |
May 13, 2005 |
PCT Filed: |
May 13, 2005 |
PCT NO: |
PCT/IT05/00275 |
371 Date: |
March 5, 2007 |
Current U.S.
Class: |
428/43 ;
428/154 |
Current CPC
Class: |
B32B 29/00 20130101;
B32B 2307/726 20130101; B32B 2555/00 20130101; B32B 7/14 20130101;
B32B 2432/00 20130101; D21H 27/40 20130101; B32B 3/266 20130101;
B32B 2250/26 20130101; Y10T 428/15 20150115; B32B 2250/02 20130101;
Y10T 428/24463 20150115; B32B 29/005 20130101; B32B 3/06 20130101;
D21H 27/32 20130101; B65H 39/16 20130101; B32B 2554/00
20130101 |
Class at
Publication: |
428/043 ;
428/154 |
International
Class: |
B65H 39/16 20060101
B65H039/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2004 |
FI |
2004A000188 |
Claims
1-35. (canceled)
36. A tissue paper sheet product wound in a roll, comprising at
least two plies joined to each other by gluing, wherein at least
one ply of said at least two plies is embossed, wherein all plies
forming said sheet product have a common width, and wherein
longitudinal edge areas of said sheet product are provided with a
greater quantity of glue than at least one intermediate area of
said sheet product.
37. The product as claimed in claim 36, wherein all the plies of
said sheet product are made of tissue paper.
38. The product as claimed in claim 36, wherein said edge areas
have a greater percentage of glued surface than said at least one
intermediate area.
39. The product as claimed in claim 37, wherein said edge areas
have a greater percentage of glued surface than said at least one
intermediate area.
40. The product as claimed in claim 36, further comprising
transverse perforated tearing lines.
41. The product as claimed in claim 37, further comprising
transverse perforated tearing lines.
42. The product as claimed in claim 38, further comprising
transverse perforated tearing lines.
43. The product as claimed in claim 36, further comprising two edge
areas at a level whereof at least one ply of the at least two plies
is embossed and has protuberances facing inward of the product, at
least a portion of said protuberances being provided with glue on
front surfaces thereof.
44. The product as claimed in claim 36, further comprising at least
one supplemental glued area, internal to the edge areas, having a
greater quantity of glue than said at least one intermediate
area.
45. The product as claimed in claim 37, including at least one
supplemental glued area, internal to the edge areas, having a
greater quantity of glue than said at least one intermediate
area.
46. The product as claimed in claim 44, wherein said supplemental
glued area is in an approximate central position between the
longitudinal edges; and defined between said supplemental area and
said edge areas are two intermediate areas devoid of glue or having
a lesser percentage of glued surface than said supplemental area
and said edge areas.
47. The product as claimed in claim 36, wherein in said edge areas
and, optionally, in said supplemental glued area, at least one of
said at least two plies has embossing according to continuous or
discontinuous annular embossing lines.
48. The product as claimed in claim 36, wherein in said edge areas
and, optionally, in said supplemental glued area at least one of
said at least two plies has embossing according to continuous or
discontinuous helical embossing lines.
49. The product as claimed in claim 48, wherein said helical
embossing lines have an inclination of no more than 300 with
respect to the longitudinal edges.
50. The product as claimed in claim 36, wherein in said at least
one supplemental glued area at least one of said at least two plies
is embossed.
51. The product as claimed in claim 36, wherein reciprocal gluing
areas of said at least two plies are provided in said at least one
intermediate area.
52. The product as claimed in claim 36, wherein in said at least
one intermediate area said at least two plies are devoid of
glue.
53. The product as claimed in claim 36, wherein a first ply of said
at least two plies is embossed along said longitudinal edge areas
and is devoid of embossing at a level of said at least one
intermediate area.
54. The product as claimed in claim 53, wherein a second ply of
said at least two plies is embossed at a level of said at least one
intermediate area and is devoid of embossing at a level of the
longitudinal edge areas.
55. The product as claimed in claim 53, wherein a second ply of
said at least two plies is embossed at a level of the longitudinal
edge areas.
56. The product as claimed in claim 53, wherein a second ply of
said at least two plies is entirely devoid of embossing.
57. The product as claimed in claim 53, wherein a second ply of
said at least two plies is embossed on an entire surface
thereof.
58. The product as claimed in claim 36, including a third ply of
said at least two plies disposed inside a first ply and a second
ply of said at least two plies.
59. The product as claimed in claim 58, wherein said third ply is
devoid of embossing.
60. The product as claimed in claim 36, wherein a first ply of said
at least two plies is provided with a first embossing along said
edge areas and with a second embossing at a level of said at least
one intermediate area, the first embossing having continuous or
discontinuous protuberances of a greater height than continuous or
discontinuous protuberances of the second embossing.
61. The product as claimed in claim 60, wherein the protuberances
of the first embossing have a lesser density than the protuberances
of the second embossing.
62. The product as claimed in claim 36, wherein a second ply of
said at least two plies is provided with a third embossing along
said edge areas, and with a fourth embossing at a level of said at
least one intermediate area.
63. The product as claimed in claim 62, wherein said third
embossing has continuous or discontinuous protuberances of a
greater height than continuous or discontinuous protuberances of
the fourth embossing.
64. The product as claimed in claim 63, wherein the protuberances
of the third embossing have a lesser density than the protuberances
of the fourth embossing.
65. The product as claimed in claim 62, wherein the protuberances
of the third embossing are disposed at a level of the protuberances
of the first embossing of a first ply of said at least two plies
and are formed by a compression of the second ply at a level of the
protuberances of the first embossing of the first ply.
66. The product as claimed in claim 62, wherein the third embossing
provided on the second ply has continuous or discontinuous
protuberances of a lesser height than continuous or discontinuous
protuberances of the fourth embossing provided on said second
ply.
67. The product as claimed in claim 66, wherein height of the
protuberances of the first embossing, the second embossing, the
third embossing and the fourth embossing produced on the first ply
and on the second ply are dimensioned to provide a substantially
uniform thickness of the product over a complete width thereof.
68. The product as claimed in claim 60, wherein the second ply has
a third embossing distributed uniformly over an entire surface, of
lesser dimensions and greater density than the first embossing with
which the first ply is provided, at a level of the edge areas.
69. The product as claimed in claim 36, wherein bands devoid of
glue or with a lesser quantity of glue are disposed between said
longitudinal edge areas and the external limit of the product.
70. The product as claimed in claim 36, wherein between said at
least two plies a bulk material is provided, said bulk material
being prevented from escaping by the longitudinal edge areas where
a greater amount of glue is provided.
71. The product according to claim 70, wherein said bulk material
is a powder and/or fiber and/or granular material.
72. The product according to claim 70, wherein said bulk material
includes a super-absorbent material.
73. The product according to claim 70, wherein gluing is provided
along said product by embossing or microembossing which includes at
least a protrusion having a form of a substantially continuous line
or projection.
74. A sheet product wound in a roll, comprising at least two plies
joined to each other by gluing, at least one ply of said at least
two plies is embossed, including longitudinally extending areas
with quantities of glue per unit of surface differing from area to
area, longitudinal areas having a greater quantity of glue
alternating with longitudinal areas having a lesser quantity of
glue.
75. A tissue paper sheet product wound in a roll, comprising at
least two plies joined to each other by gluing, at least one ply of
said at least two plies is embossed, wherein all plies forming said
sheet product are made of tissue paper and wherein longitudinal
edge areas of said sheet product are provided with a greater
quantity of glue than at least an intermediate area of said sheet
product.
Description
TECHNICAL FIELD
[0001] The present invention relates to sheet products, with two or
more plies joined to one another by gluing, for example and in
particular (although not exclusively) made of tissue paper.
[0002] More specifically, the invention relates to sheet products
especially of the type wound in a roll, such as kitchen towels,
toilet paper and the like.
STATE OF THE ART
[0003] In the production of toilet paper, kitchen towels and other
products made of tissue paper or creped paper, two or more plies of
paper joined to one another by ply-bonding or gluing are normally
used. When the plies are joined by gluing they are normally
embossed, that is, subjected to permanent mechanical deformation
with the formation of protuberances on the plies. The glue is
applied to the front surface of the protuberances of at least one
of the two plies and the plies thereby embossed and provided with
glue are laminated between two embossing rollers or between one
embossing roller and one laminating roller. Various embossing and
laminating devices have been designed for this purpose.
[0004] Application of the glue to join the plies causes some
drawbacks. In the first place the glue--being an expendable
material--increases the cost of the finished product. In the second
place, the presence of glue decreases the softness of the product,
which becomes more rigid, and has a negative influence on the
absorption capacities thereof.
[0005] Various systems have been designed to reduce the amount of
glue used to join the plies, and typically the number of
protuberances to which the glue is applied tends to be reduced.
[0006] However, these measures are not always sufficient to obtain
a product with the desired softness and/or having the desired
characteristics of absorption.
OBJECTS AND SUMMARY OF THE INVENTION
[0007] The object of the present invention is to produce a product
which reduces or eliminates, either entirely or partly, the
drawbacks mentioned above.
[0008] More specifically, the object of the present invention is to
produce a multi-ply tissue paper product wherein distribution of
the glue is optimized to join the plies adequately, with a
reduction of the negative consequences of the glue on the
characteristics of softness and/or on the absorption capacities of
the product.
[0009] These and other objects and advantages which shall become
apparent to those skilled in the art from reading the text below,
are obtained in substance with a sheet product, for example and in
particular paper and specifically (although not exclusively) tissue
paper, comprising at least two plies joined to each other by
gluing, wherein at least one of the plies is embossed,
characterized in that it has longitudinal edge areas or bands on
which a greater amount of glue is applied with respect to at least
an intermediate area, that is, an area disposed within the
longitudinal edges of the product. In particular, according to the
invention the edge areas have a higher percentage of glued surface
with respect to the percentage of glued surface in the intermediate
area or areas of the product.
[0010] The invention is based on the idea that to join the plies
forming the finished product glue only requires to be distributed
in areas, and that during use the paper product is utilized in
different ways from area to area. The invention is thus based on
the idea of reducing the quantity of glue in those areas where it
can have a negative effect on the characteristics of softness
and/or absorption capacities of the product, concentrating the
presence of the glue mainly along the edge areas.
[0011] In fact, in the case of toilet paper, for example, it is
always used prevalently in the central area of the sheets of paper,
while in normal use the edge areas are not utilized. Therefore, a
quantity of glue concentrated on the edge areas does not reduce the
characteristics of softness in the area of the product, which comes
into contact with the user. On the other hand, the glue applied
along the edges, or prevalently along the edges, guarantees optimum
joining of the plies.
[0012] Also in the case of kitchen towels, the presence of glued
longitudinal edge areas and intermediate areas devoid of glue or in
any case having a smaller quantity of glue attains the aforesaid
advantages of increased softness and absorption capability with
respect to traditional products, thanks to the reduction in the
quantity of glue especially in the intermediate areas, that is, in
the central areas of the product.
[0013] In the specific case of kitchen towels, it is advantageous
to provide S supplementary glued areas, having an extension
essentially parallel to the longitudinal edges, so that the
finished product in substance has more than two glued bands or
areas disposed along the longitudinal edges and in intermediate
positions with respect to the transverse extension of the product.
By producing these areas wherein gluing is concentrated by means of
more evident embossing, for example, linear embossings with greater
height with respect to micro-embossing distributed over the entire
remaining surface of the product, the kitchen towel can attain
further advantages. In fact, the presence of areas with more
evident and glued embossing increases grip of the hand on the sheet
of paper resulting in an increased cleaning effect, useful when the
product is used, for example, to clean or dry the surfaces of
furniture, dishes or other objects. The presence of embossings in a
central area of the product, especially if obtained with continuous
instead of discontinuous projections, makes it possible to obtain a
sort of scoring effect and thus invites folding of each sheet of
kitchen towel, with further advantages during use.
[0014] Gluing along the edges, especially if obtained by means of
micro-embossing or embossing according to continuous lines or
projections, can also be used as a sort of lateral closure of the
multi-ply product, to allow products of various types to be
inserted and retained between the plies. For example, between the
plies an absorbent or super-absorbent material can be inserted, in
the form of fibers, granules, powder or the like. Suitable
super-absorbent materials typically those used in the production of
sanitary napkins, baby diapers or other similar products. These
materials are often polymer-based. Preferably, in particular when
web product is a kitchen towel or a wiper, the super-absorbent
material is of edible type.
[0015] According to a different aspect, the invention relates to a
sheet product wound in a roll, for example toilet paper or kitchen
towels, with two or more plies joined by gluing, preferably at
least partly embossed, characterized in that it has longitudinal
areas or bands which contain quantities of glue varying area to
area, that is longitudinal areas with different quantities of glue
per surface unit.
[0016] Further advantageous characteristics and embodiments of the
product according to the invention are indicated in the appended
claims and shall be described in greater detail with reference to
some examples of embodiment ilustrated in detail hereunder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will be better understood by following the
description and accompanying drawings which show preferred although
non-limiting embodiments of the invention. More specifically, in
the drawing:
[0018] FIG. 1 shows a roll or log of considerable axial length
which, after being cut orthogonally to the longitudinal axis
thereof, is divided into a plurality of rolls destined for final
use;
[0019] FIG. 2 shows a plan view of a portion of a roll of toilet
paper produced according to the invention;
[0020] FIG. 3 shows a variant of embodiment of the toilet paper in
FIG. 2;
[0021] FIGS. 4 to 11 show greatly enlarged schematic cross sections
of a toilet paper type product produced according to the
invention;
[0022] FIG. 12 shows a plan view of a portion of a roll of kitchen
towel according to the invention;
[0023] FIGS. 13 to 16 show greatly enlarged schematic cross
sections of a kitchen towel type product produced according to the
invention in various embodiments;
[0024] FIG. 17 shows a diagram of an embossing and laminating unit
to obtain a product according to the invention;
[0025] FIG. 18 shows a greatly enlarged schematic cross section of
a further embodiment of the invention; and
[0026] FIGS. 19 and 20 show a schematic front view of possible
embossing patterns along the edges of web sheet material,
particularly suitable for retaining material in powder or fiber
form between the plies forming the sheet material.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0027] FIG. 1 shows a log, that is, a roll of considerable axial
length, delivered from a rewinding machine, located downstream of
an embossing unit which performs, on the tissue paper web material
or the like, differentiated embossing with differentiated gluing to
obtain the objects mentioned above. The log, indicated as a whole
with L, will subsequently be cut orthogonally to the axis A-A
thereof, to be divided into a plurality of rolls R of a smaller
axial length, corresponding to the final dimension of the product
destined for use. The ends of the log have been trimmed to
eliminate the irregular portion which forms in this end area during
winding.
[0028] As shown schematically in FIG. 1 and illustrated in greater
detail hereunder by a series of examples of embodiment, the web
material indicated as a whole with N of which the log L is composed
is embossed differentially with areas with increased embossing at
the level of cutting planes P indicated with a dashed line in FIG.
1, along which the logs will be cut to be divided into individual
rolls R.
[0029] FIG. 2 shows a length of toilet paper formed by web material
N wound on a roll R obtained by transverse cutting of the log L in
FIG. 1.
[0030] The web material N is formed by two or more plies glued to
one another as will be described with reference to the following
figures. Transverse incision or perforation lines T divide the web
material N into single sheets F destined for final use. Along the
longitudinal edges B of the web material N are two longitudinal
edge areas indicated with 1, concentrated in which is all or most
of the glue that joins the plies forming the web material N.
Between the two longitudinal edge areas 1 is an intermediate area 3
essentially devoid of glue or, in particular cases, with a smaller
quantity of glue compared to the glue applied along the edge areas
1.
[0031] FIGS. 4 to 10 show various forms that can be taken by the
web material N in a greatly enlarged schematic cross section. With
initial reference to FIG. 4, in this case the web material is
formed by two plies V1 and V2 of tissue paper. The ply V1 has,
along the longitudinal edge areas 1, first embossing formed by
geometrically shaped protuberances 7 of considerable dimensions.
Typically, the protuberances 7 can be distributed with a density
ranging from 3 to 15 protuberances/cm.sup.2, it however being
understood that these values are not limiting. The height of the
protuberances can be in the range of 0.1-2 mm, although also in
this case the values are provided purely as a non-limiting
indication. In the intermediate area 3 the ply V1 is provided with
micro-embossing 9 formed by protuberances of greater density and
lesser dimensions, in particular of lesser height, with respect to
the protuberances 7 of the first embossing.
[0032] A glue C is applied to the front surfaces (facing the inside
of the web material N) of the protuberances 7 of the first
embossing, to allow the ply V1 to adhere to the underlying ply V2.
The latter is provided with micro-embossing formed by a series of
small protuberances 11, which can have dimensions equivalent to the
protuberances 9 forming the micro-embossed central or intermediate
area 3 of the ply V1.
[0033] Reciprocal gluing of the two plies V1 and V2 consequently
occurs in the longitudinal edge areas 1, wherein the glue C applied
to the protuberances 7 is concentrated. The intermediate area 3 of
the product is devoid of glue. This area is the area, which--in
normal use of toilet paper--comes into contact with the hands and
body of the user. The absence of glue in this area guarantees
maximum softness and absorbent power, while the glue C applied
along the edges does not impair these characteristics in those
bands or areas of the product which are practically unused, while
guaranteeing sufficient reciprocal adhesion of the plies.
[0034] FIG. 5 shows a variant of embodiment of the product in FIG.
4. The same numbers indicated identical or equivalent parts to
those in the example in FIG. 4. The web product N is composed in
this case of three plies, of which the external plies V1 and V2 are
embossed as described above, while the intermediate ply V3 is
devoid of embossing. The glue C applied to the front surfaces of
the protuberances 7 in the longitudinal edge areas 1 seeps through
the intermediate ply V3 and allows reciprocal bonding of the three
plies.
[0035] The products produced as illustrated in FIGS. 4 and 5 can be
obtained with embossing and laminating units of known type not
described herein. For example, an embossing and laminating device
of the type disclosed in U.S. Pat. No. 6,755,928 and in U.S. Pat.
No. 6,681,826 can be used.
[0036] The products illustrated in FIGS. 4 and 5 are typically
embossed according to discontinuous tips or protuberances, for
example frusto-conical shaped or frusto-pyramidal shaped
protuberances, according to known techniques. However, it would
also be possible to produce the product according to the invention
with other forms of embossing. For example and in particular,
embossing can be produced according to continuous lines, that is,
with continuous protuberances with a linear and prevalently
rectilinear extension. This is the case of the product illustrated
schematically in FIG. 6, where identical or equivalent parts are
indicated with the same reference numbers as FIG. 4. The
protuberances 7, 9 and 11 are composed in this case of lines of
parallel protuberances, or slightly inclined with respect to the
edges of the web material N. The finished product will therefore
have the appearance of a lined product rather than a product
embossed with points. Also in this case, the glue C is applied to
the protuberances (again indicated with 7) with greater dimensions
produced along the longitudinal edge areas 1 of the web material N,
while lines with lesser dimensions, and in particular of lesser
height, are produced in the central or intermediate area 3,
distributed with a denser pitch and devoid of glue. The underlying
ply V2 is produced with a series of linear protuberances 11 with
dimensions and pitch essentially equivalent to those of the lines
forming the embossing 9.
[0037] The linear embossing 9 and 11 could be replaced by
micro-embossing with a frusto-pyramidal or frusto-conical shape,
that is, discontinuous rather than continuous.
[0038] The product in FIG. 6 could also be provided with a third
smooth, that is, unembossed, intermediate ply V3.
[0039] FIG. 7 shows a modified embodiment of the product in FIG. 4.
In this case, along the longitudinal edge areas 1 the ply V2 is
compressed at the areas in which the glue C is applied, that is, at
the front surfaces of the protuberances 7. This is obtained by
laminating the two plies V1, V2 after applying the glue between an
embossing roller which produced the embossings 7 and 9 and on which
the ply Vi is still adhering, and a prevalently smooth lamination
roller which defines a lamination nip together with the embossing
roller which embossed the ply V1, through which nip the plies V1
and V2 are fed. The lamination roller can be coated in a rubber of
appropriate rigidity to obtain re-embossing of the ply V2 at the
level of the protuberances 7, with the depth of said re-embossing
varying according to the softness of the laminating roller.
[0040] The product in FIG. 7 can also be provided with a third
intermediate ply, which in this case would be embossed lightly
through the effect of the yield of the laminating roller along the
longitudinal edge areas 1 in which the glue C joins the plies
together.
[0041] FIG. 8 shows--again in a greatly enlarged schematic cross
section--a web product N such as toilet paper formed by two plies
V1 and V2. The ply V1 is embossed along the longitudinal edge areas
1, wherein it has protuberances again indicated with 7. In this
example the protuberances have lesser dimensions (especially
height) with respect to the dimensions of the protuberances 7 of
the previous embodiments. In fact, this can be a micro-embossing,
for example with protuberances having a density of around 15-100
protuberances/cm.sup.2 and preferably 20-40 protuberances/cm.sup.2.
The height of thee protuberances 7 can be around 0.1-0.5 mm,
preferably 0.1-0.3 mm, although these sizes should not be
considered as limiting.
[0042] A glue C is applied to the front surface of the
micro-embossings 7 to join the ply V1 to the ply V2. The
intermediate area 3 of the ply V1 is devoid of embossings and
devoid of glue.
[0043] In this example the ply V2 is smooth in the edge area 1 and
embossed with micro-embossing formed by protuberances indicated
again with 11 in the intermediate area 3. The density and
dimensions of the protuberances 11 can, for example, be comparable
to those of the protuberances 7. The two plies V1 and V2 can be
joined by lamination by means of a zone laminating roller, i.e.
having annular bands, which act against an embossing roller that
produces the protuberances 7. The ply V1, still adhering to and
engaged with the embossing roller, and the ply V2 previously
embossed in the band or intermediate area 3 by a separate embossing
unit, are fed through the nip between the embossing roller and the
laminating roller.
[0044] FIG. 9 shows a web material N similar to the one in FIG. 8
wherein, however, the lower ply V2 is completely devoid of
embossing.
[0045] The web material N in FIG. 10 is similar to the product in
FIGS. 8 and 9, but the lower ply V2 is typically embossed with
micro-embossing formed by protuberances 11 along its entire
extension, while the ply V1 is embossed with micro-embossing solely
in the longitudinal edge areas 1 and also in this case the glue is
applied along the aforesaid longitudinal areas 1. FIG. 11 shows a
web product N formed once again by two plies V1 and V2 in a
modified embodiment. In this case, besides the protuberances 7 and
11, which are produced in the longitudinal edge areas 1 on both
plies V1 and V2 (and which can be micro-embossing protuberances),
embossing protuberances 13, 15 are provided in the ply V1 and in
the ply V2 at the level of the intermediate area 3. These
protuberances can be coincident or staggered and can either be
provided with glue or devoid of glue. The glue to join the plies is
in any case applied along the longitudinal edge areas, as described
in the previous examples. The protuberances 13, 15 can have an
exclusively decorative function or contribute towards reciprocal
bonding of the plies V1, V2, without this impairing the
characteristics of softness and high absorption capacity
concentrated in the intermediate area 3 of the product, thanks to
the low percentage incidence of the glued surface represented by
the front surfaces of the protuberances 13, 15. Any glue applied to
the protuberances 13 and/or 15 can also be a colored glue to give
the finished product a particular aesthetic effect.
[0046] FIG. 3 shows, in a plan view, a portion of the web product N
produced with this configuration. In the central or intermediate
area 3 essentially devoid of glue, the web product N has flowery
decorative patterns formed by the embossing protuberances 13, 15.
As shown by way of example in FIG. 3, these patterns are extremely
sparse and therefore--even if provided with glue--do not negatively
influence the characteristics of the product to any appreciable
extent.
[0047] In the examples of embodiment described above reference is
always made to a toilet paper type product, although as mentioned
before the concept on which the invention is based can also be
applied to other tissue paper products wound in rolls, such as
kitchen towels.
[0048] FIG. 12 shows a plan view of a portion of web material
coming from a roll of kitchen towel. The same reference numbers
indicate identical or equivalent parts to those illustrated in
FIGS. 1 and. 3. In the example in FIG. 12 it can be seen that this
product differs from the product in FIGS. 1 and 2 essentially due
to the greater length of each sheet F into which the web material N
is divided by the transverse perforation lines T. Moreover, in the
example in FIG. 12, besides the two longitudinal edge areas 1, the
web material N has a supplementary glued area 4, essentially
parallel to the longitudinal edge areas 1. Two areas 3 essentially
devoid of glue are defined between each longitudinal edge area 1
and the supplementary central glued area 4. As shall be explained
with reference to the embodiments illustrated schematically in
FIGS. 13 to 16, in practice the supplementary gluing areas 4 can
also be more than one.
[0049] FIG. 13 shows as an example a greatly enlarged schematic
cross section of a web material N produced with a first ply V1, a
second ply V2 and a third intermediate ply V3 essentially devoid of
embossing. The ply V1 has longitudinal edge areas 1 embossed with a
first embossing formed by protuberances 7 on the front surfaces
whereof the glue C is applied. In this example there are also two
supplementary gluing areas 4, in which the ply V1 is again embossed
with protuberances, indicated once again with 7, with dimensions
(in particular height) essentially the same as the protuberances 7
of the longitudinal edge areas 1. Glue C is also applied to these
protuberances 7 in the supplementary intermediate areas 4. The
lower ply V2 has essentially uniform embossing or micro-embossing
formed by protuberances 11. Lamination in an appropriate lamination
nip of the plies V1, V2 and V3 causes reciprocal gluing, also
thanks to the glue C seeping through the ply V3 in the longitudinal
edge areas 1 and in the supplementary intermediate areas 4.
Conversely, the areas 3 are devoid of glue.
[0050] FIG. 14 shows a product analogous to the one in FIG. 13,
devoid of the intermediate ply V3 and produced with linear
protuberances instead of the interrupted protuberances of FIG. 13,
which can be of the frustum-pyramidal or frustum-conical shaped
type. It will be understood that an intermediate ply V3 can also be
provided in the web product N in FIG. 14 and that the intermediate
ply V3 in FIG. 13 can be omitted.
[0051] FIGS. 15 and 16 show two embodiments of the web material,
wherein the embossing protuberances of the various areas into which
the web material N is divided differ in form. In the example in
FIG. 15 these are linear protuberances, i.e. formed by continuous
embossing lines parallel to the edges B of the web material N or
slightly inclined with respect thereto, while in the example in
FIG. 16 these are frustum-conical or frustum-pyramidal shaped
protuberances, i.e. discontinuous, protuberances. In both cases the
embossing areas 1 and 4 are identified on the ply V1 with
protuberances of a greater height provided with glue C, while the
intermediate areas 3 are provided with embossing protuberances with
lesser dimensions and lesser density, devoid of glue. The ply V2 is
embossed in an essentially complementary way, that is, with
micro-embossings, or in any case embossings of lesser height and
increased density at the level of the longitudinal edge areas 1 and
of the supplementary gluing areas 4, and protuberances of greater
height and decreased density in the intermediate areas 3.
[0052] As clearly indicated in the sections of FIGS. 15 and 16,
this particular arrangement makes it possible to obtain an
essentially uniform apparent thickness in the overall web product
N. This facilitates winding of the web material and formation of
logs and therefore rolls of an essentially uniform thickness. In
addition or alternatively to this, to obtain the same object, in
all the cases, a calendering unit can also be provided downstream
of ply joining, composed of a pair of essentially smooth rollers
with an essentially constant diameter, disposed at a distance
whereat the composite sheet, formed by two or more laminated plies,
is subject to calendering to uniform the thickness of the composite
sheet on the entire surface thereof.
[0053] FIG. 17 schematically shows an embossing-laminating unit to
produce a web product of the type shown in FIG. 16. Two steel
embossing rollers are shown with 101 and 103, provided with
protuberances 107, 109 for the roller 101 and 111, 113 for the
roller 103. The protuberances 107 and 111 have a lesser density and
greater dimensions (in particular height), while the protuberances
109 and, 113 have lesser height and greater density. The ply V1 is
embossed by the cylinder or embossing roller 101 and a pressure
roller 115 coated with rubber or another yielding material, while
the ply V2 is embossed between a second pressure roller 117 and the
embossing roller or cylinder 103. The sectioned areas of the
embossing rollers are shown according to different section planes,
as represented schematically with different hatching, as the
protuberances of different dimension provided on these rollers are
disposed in areas staggered axially along the extension of the
rollers, as is apparent in from the section in FIG. 16.
[0054] Disposed along the circumferential extension of the
embossing roller 101 is a laminating roller 119, for example coated
in a rubber with less yield than the coating of the rollers 115 and
117. The roller 119 cooperates with the embossing roller 101 and
causes reciprocal lamination of the plies V1 and V2 at the level of
the protuberances of greater height 107 provided on the embossing
roller 101. The hardness of the coating of the laminating roller
119 is such that it does not compress the protuberances 9 and 11
produced in the areas 3 devoid of glue of the web material N. On
the other hand, through the effect of lamination the protuberances
at the level of the areas 1 and 4 are compressed against the
protuberances 7 formed by the tips or protuberances 107 of the
embossing roller 101.
[0055] The laminating roller 119 can be produced in bands, that is,
areas with a greater diameter, which perform lamination of the
longitudinal edge areas 1 and, optionally, of the supplementary
central or intermediate areas 4, of the web material, without
compressing the intermediate areas which, being devoid of glue, do
not require to be laminated.
[0056] FIG. 17 shows a device in which the embossing rollers are
provided with discrete protuberances, although it is understood
that alternatively they can be provided with linear protuberances,
that is, in the form of annular or helical projections, to produce
the products shown in FIGS. 6, 14 and 15 or other equivalent
products.
[0057] The schematic sections described and illustrated above are
to be considered purely exemplification, it being apparent that the
same inventive concept can be produced in various ways and with
various arrangements, without departing from the principle of
producing a multi-ply web material wound in a roll, divided into
individual sheets F by transverse perforation lines T, wherein the
glue is prevalently or exclusively concentrated in edge areas and,
optionally, in one or more supplementary intermediate gluing areas
between the two edges of the material.
[0058] For example, while in the examples illustrated above
reference has always been made to products wherein the bands or
lateral edge areas are embossed with a greater height than the
central areas, it must be understood that this condition is not
essential to obtain non-uniform distribution of glue, with
concentration which is greater along the edges and lesser in the
center. In fact, this result can be obtained even if the ply which
receives the glue has embossing of uniform height along the entire
extension thereof. In this case, concentration of glue in the
lateral edge areas and, optionally, in one or more intermediate
areas, can be obtained with an appropriate configuration (in
annular bands) of the glue dispensing roller. In this case, a
product of the type shown schematically in the section in FIG. 18
is obtained. The same numbers indicate identical or equivalent
parts to those in the previous figures. The protuberances 7 and 9
have in this case the same height, but only the protuberances 7
have been received the glue C, thanks to the use of a cliche type
glue roller or the like.
[0059] In the case in which the area essentially devoid of glue has
an embossed decoration, this can also be produced with a
combination of protuberances of two or more different heights, as
known in the art, preferably of lesser height than the
protuberances along the edge areas, which are the only ones to
receive glue.
[0060] In the above text and in the appended claims, it must be
understood that edge areas are not necessarily intended as areas
which reach the final lateral limit of the product. In other words,
although applied with greater concentration (or exclusively) in the
edge areas, the glue might not stretch to the final lateral limit
of the product, instead leaving a thin longitudinal strip devoid of
glue on each of the longitudinal edges of the product. This can be
obtained with a cliche type glue applicator roller, which has areas
devoid of glue along bands which, in the final product, extend
along the longitudinal edges. This is advantageous especially in
the case wherein the product is Wound in rolls obtained from
cutting logs of considerable axial length. In fact, in this case
logs can be produced wherein the thin strips at the level of the
cutting planes (along which the log is cut by the blade of the
cutting machine to be divided into individual rolls) are devoid of
glue. This circumstance offers the advantage of reducing or
eliminating drawbacks deriving from interaction of the blade with
the glue. This advantage is also obtained in the case in which the
sheet product is divided into longitudinal strips of a width
corresponding to the width of the finished product before being
wound in rolls, in a slitter-rewinder.
[0061] FIGS. 19 and 20 show schematic front views of two different
embodiments of an embossing and gluing pattern which is
particularly suitable when between the plies V1 and V2 forming the
web material N a material in powder, fiber or granular form is
arranged, such as for example a super-absorbent material, such as a
super-absorbent polymer. In these figures the same reference
numbers designate parts identical or equivalent to those shown in
the previous figures. Along the two edge areas 1 of each sheet F
into which the web material N is subdivided by the perforation and
tearing lines T, embossing patterns are provided, which are formed
by two distinct kind of protuberances designated 7A and 7B. Besides
these protuberances which are obtained by embossing as disclosed
above, and at the level of which glue is applied, micro-embossing
protrusions may be provided which can be distributed over the
entire surface of the plies. The protrusions 7A have a linear and
continuous development; thus they form a continuous barrier along
the entire longitudinal extension of the web material, preventing
the powder or similar material retained between the plies V1, V2
from escaping. Conversely, the protrusions 7B are discontinuous and
have mainly an ornamental function. The area between two edge
regions 1, i.e. bridging the edges B of the weblike material are
advantageously devoid of super-absorbent material between the plies
(since it is the central area rather than the edge areas of the
product which is actually used), in order to avoid dispersion of
the material in the environment as well as problems during cutting
of the logs L into rolls R (FIG. 1).
[0062] It is understood that the drawing purely shows an example
provided by way of practical arrangement of the invention, as said
invention may vary in form and arrangement without however
departing from the scope of the concept on which the invention is
based.
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