Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~084473
The present invention relates to a roll of web material,
for example paper, plastic film, cloth or the like, which is
rolled onto a core in the interior of the roll.
Known cores, onto which web materials are rolled, are
prefabricated and generally consist of cylinders of glued paper
or glued cardboard, but there are also other types of cores.
For example in a number of rolls two cardboard rings or two
wooden plugs in the shape of a conic frustrum with center holes,
are used. These rings or plugs are placed at both ends of the
rolls, to assure , as do the glued cardboard and paper cylinders,
that the rolls are correctly rolled and have the correct shape,
but they are also a sort of hub in the rolls when the web
material is rolled off from its outer circumference. With the
type of roll in which the web material is taken off centrally,
however, i.e. through the center hole of the roll, the cores,
usually in the form of cardboard rings, must be removed before
the free web ends in the centeT hole of the rolls can be taken
out and the rolling off from the inner circumference of the
rolls can begin. Rolls from which the web material can be taken
off centrally are of course known even completely without a
core, but rolls of this type have proved quite susceptible to
collapse, and have therefore been used less and less, especially
since collapse involves a complete blocking of the center hole
so that the free web end in the same is held fast and cannot be
pulled our or even found in some cases. Solid rol cores are
also known. These can have a wide variety of forms. Some take
the form of wooden dowels and others take the form of extended
discs of varying thicknesses. Common to the solid cores is that
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fact that they cannot be used for rolls from which the web material is to be
rolled off centrally. They are generally much too difficult to remove from
the rolls as a result of the great friction against the web material. This
friction makes axial extraction of cores from the rolls practically impossible. ~'~
Even if the use of the known prefabricated roll cores always pro-
duces stable rolls which do not collapse, these two advantages do not out-
weigh the disadvantages of these cores. Prefabricated cores, whether they ~ :
are hollow or solid, have tubular cylindrical or annular shape, or are in the
form of dowels, discs or plugs, are relatively expensive, at the same time
as they as a rule always require storage space as well as manual handling in
application. This makes their use additionally expensive. In addition to
this, as was stated previously, they are not suitable for use in rolls which
are to be rolled off through the center hole of the roll.
The purpose of the invention is to remove the disadvantages involved
in the known prefabricated roll cores, and to produce a new type of roll, in
which the use of an expensive prefabricated core requiring space and handling
is not required.
According to one aspect of the present invention there is provided
a cylindrical roll of web material having a central opening and forming a
supply of said web material and a cylindrical core in the central opening of
said roll having a stiffness sufficient to support said roll against axial
and radial collapse, characterized in that: the core comprises a plurality
of turns of said web material and a fixing agent distributed over at least
one surface of the web material forming the core so as to fix said core wind-
ings into a substantially rigid core; the web material forming the core is an
integral continuation of the web material forming the roll; and the fixing
agent has a bonding strength less than the strength of the web material,
whereby the turns of mzterial in the core can be unwound together with the
material of the cylindrical roll for use in the same manner, while leaving
no residual core.
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10~473
According to another aspect of the present invention there is
provided a method of forming a cylindrical roll of web material wound on a
central, substantially rigid core, said method comprising: winding a first
plurality of turns of said web material onto a spindle; applying a fixing
agent having a strength less than that of the web material to at least one
surface of the web material forming the first plurality of turns, before it
is so wound, so as to form a substantially rigid core from the fixed and
wound turns; continuing to wind the web material onto the spindle to form
said roll; and retracting said spindle from said core.
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lC)B44'73 ~
In a roll of this type, the use of a prefabricated
core is completely eliminated. Since a core constructed in one
piece with the roll material is made during the first stage of
the rolling operation of the roll itself, this eliminates all
of the space and handling requirements of the known prefabricated
cores.
The turns of material in the core can be unrolled
from either the outer or the inner circumference of the core,
together with the material rolled onto the core. Consequently,
lQ the roll is not limited, as are the known rolls, to one or the
other type of unrolling. Instead it is equally suited to
rolling off peripherally and centrally.
The fact that the material in the core can be used in ~
the same manner as the rest of the material in the roll means -
direct savings as compared with the use of the known roll cores,
which as a rule are thrown away after use, since reuse is not
economically justifiable.
In an especially suitable embodiment for a roll
according to the invention the core is tubular. To facilitate
2Q central unrolling of the web material, a core of this type can
haYe a free end of the web material inside said core. This
free end is intended to serve as an easily grasped gripping
end for rolling off.
The invention will be explained in more detail below
with the aid of a suitable embodiment.
~ olls of web material consisting of creped paper are
to be
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produced with a so-called open center hole. The paper is to be
rolled onto a core in the interior of the TOll. According to
the invention this core is to be made in one piece with the
material rolled onto the same and consists a number of turns of
the material, and these turns are fixed in relation to one
another. For this purpose the beginning end of the creped paper
web is laid as usual around a known rolling spindle, preferably
expandable, which is allowed to rotate while a number of the
first innermost turns are fixed in relation to one another,
during the formation of the roll, with water to form a roll
core, or with a mixture of water and a binder, for example
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starch, CMC, PVA or another water-soluble binder in
concentrations between 0,05-2~ depending of the desired binding
effect.
lS If the binding or fixing agent is only water, the amount
should be kept so low that the paper web is not wetted through.
Preferably the binding or fixing agent should be applied to
that side of the web which is not in direct contact with the
rolling spindle, and if the fixing agent is a binding agent
mixed with water the viscosity should be kept so low that a
good and even distribution is obtained.
The application of the fixing agent can be done in many
different ways, e~g. by spraying or spreading on the web or by
means of a press, glue press or other mechanical device, which
produces a suitable distribution on and in the web. With such
an application of the fixing agent, the amount of agent can be
regulated so that the paper in the core of the roll remains
practically unaffected as to usability, and the whole roll
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including the core is usable. -
In the event that a core is desired in the form of a really ~
hard and stiff tubular sleeve, the amount of fixing agent can ~;
be increased, or one can use a water-free fixing agent or a
type of wax or glue, hot melt for example, to achieve the same
effect. It is of course also possible to retain the original ~ -
fixing agent and instead increase the number of wraps or turns
in the core. ;
By choosing a more powerful binding agent, such as glue,
and increasing the number of turns of the paper solid and
stiff cores or cylinders can be obtained.
In practical tests with starch as a fixing agent for webs
of creped paper, good results were achieved without the
innermost layers of paper which form the core of the roll,
being directly glued together.
Possibly heating or cooling can also be included in the
operations in the making of the roll core.
In the making of rolls of other web material binding agents
are selected for fixing their cores from case to case, which
produce a suitable strength in combination with the web
material in question to form a functional core in the rolls.
The invention is not limited to the embodiment described
above. Rather it can be modified in many ways within the scope
of the claims.
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