[0001] The present invention relates to a support core for rolls of continuous sheet materials,
which is especially used, though not exclusively, with advantage in the paper industry.
[0002] Paper manufacturing farms, both those which produce paper webs (tissue) and those
which convert them into finished products, (such as paper for sanitary or food use)
currently use cardboard cores as a support for rolling up their product. Cardboard
cores have, nevertheless, several inconveniences. First, the cardboard constituting
the cores is not recyclable: in fact, in order to ensure a sufficient strength to
the cores, special binders are added to the pulp that cannot be removed by the usual
pulping process. As a consequence, these cores are disposed as a special waste. Furthermore,
due to the high unrolling speed, cardboard cores cannot be reused in no more than
one or, at the most, two working cycles.
[0003] It must also be taken into account that, due to their hygroscopicity, cardboard cores
are easily perishable and, due to their poor mechanical strength, tend to squash and
ovalize, thus becoming unusable.
[0004] Finally the cardboard cores presently in use are easily flammable and constitute
a further cause of fire in an environment, such as that of the paper industry, where
this risk is already very high.
[0005] Therefore there is a strong, unsatisfied need in this field to have available an
alternative to the cardboard cores presently in use to overcome the prior art drawbacks.
[0006] It is an object of the present invention to provide a support core for rolls of continuous
sheet materials, such as paper, having excellent mechanical strength and dimensional
stability and capable of being used a number of times much higher than that allowed
by the support cores presently in use.
[0007] Another object of the present invention is to provide a support core for rolls of
continuous sheet materials of the above mentioned type, which can be recycled at the
end of its useful life.
[0008] A further object of the present invention is to provide a support core of the above
mentioned type which is stable in the presence of humidity and fire-resistant.
[0009] The above objects are achieved with the support core for rolls of continuous sheet
materials according to the present invention, the main feature of which is the fact
that it is made of a plastic material comprising high-density filled polyethylene
with a density comprised between 0,945 and 0,962 g/cc, as well as a flame-retardant
in a weight percentage not higher than 2%. As a filler, there may be advantageously
used talc (0-36%) to increase the stiffness, calcium carbonate (0-30%) to improve
the workability, carbon black (0-2,5%) to improve the resistance to the atmospheric
agents and UV rays, thus allowing an outdoor storage. These additives can be used
alone or in combination. As a flame-retardant additive a commercially available masterbatch
can be used such as those based on organic bromide compounds or nitrogen-phosphorous
compounds, for instance those produced by the firm VIBA of Tradate (Varese, Italy),
or equivalent flame-retardant products well-known to a person skilled in the art.
[0010] The melt index of the polyethylene is comprised between 0,05 and 0,5 (basis 5 Kg,
190°C).
[0011] The composition of the mixture of raw material used for the manufacture of the support
cores according to the invention may vary as a function of the specific needs of the
user, taking also into account the thickness and the requested degree of stiffness.
Although the composition may vary according to the above mentioned requirements, a
particularly preferred weight composition for the manufacture of support cores is
the following:
| HDPE |
80% |
| Flame retardant additive |
1% |
| Talc |
8% |
| Calcium carbonate |
9% |
| Carbon black |
2% |
[0012] With the above mixture there can be produced support cores having, for example, a
length up to 15 m, a thickness from 3 to 30 mm and a diameter from 16 to 500 mm, usable
for example for producing paper rolls of a weight up to 3 tons.
[0013] The polyethylene support cores according to the present invention exhibit significant
advantages over the conventional cardboard cores and in particular greater resistance,
possibility of being reused for several times, easy of being disposed, resistance
to humidity and chemicals. Moreover they are fireproof and have an high dimensional
stability. The latter property allows the cores to be reused for several times thanks
to the low risk of deformation to which they are subjected. Furthermore, it must be
taken into account that the above advantages are achieved thanks to the special mixture
of materials, which the cores of the invention are made of, without adversely affecting
the cost of the product that can be marketed at competitive prices with respect to
the conventional cardboard cores.
[0014] The support cores according to the present invention will be put on the market in
a wide range of thicknesses and diameters as requested by the specific used which
they are destined to. The use of the support cores of the invention is not limited
to the paper industry, but can be extended to other fields such as textile industry.
[0015] Variations and/or modifications can be brought to the support core for rolls of continuous
sheet materials according to the present invention, without departing from the scope
of the invention itself as set forth in the appended claims.
1. A support core for continuous sheet materials to be rolled up on it characterized
in that it is made of high density polyethylene, said density being comprised between
0,945 and 0,962 g/cc and comprising a flame retardant additive and a filler material.
2. The support core according to claim 1, in which said filler material is selected from
talc, calcium carbonate, carbon black, their mixtures and functionally equivalent
products.
3. The support core according to claim 2, in which said high density polyethylene is
a compound with the following weight percent composition:
| HD polyethylene |
70-98% |
| Flame retardant additive |
0,5- 2% |
| Talc |
0-36% |
| Calcium carbonate |
0-30% |
| Carbon black |
0-2,5% |
