Title of Invention

SYNTHETIC LEATHER WITH HIGH INFRARED RADIATION REFLECTANCE

Abstract A synthetic leather (1) comprises a plurality of superposed layers of polymeric material, obtained by spreading, in at least one (4) of which are dispersed one or more pigments capable of colouring the leather, preferably of a dark colour. The pigments have overall a reflectance to radiation of the near infrared of more than 40%.
Full Text Synthetic leather with high infrared radiation reflectance.
DESCRIPTION
Technical field
The present invention relates to a synthetic leather with high
infrared radiation reflectance, having the characteristics mentioned in the
preamble of the main claim.
Technological background
The present invention finds particular, although not exclusive,
application in the field of manufacture of synthetic leathers for covering
saddles and accessories for cycles, motorcycles and vehicles in general.
In this field it is known to employ low-cost synthetic leathers as
covering for an inner padding of soft polymeric material, for example an
expanded polyurethane.
A specific family of synthetic leathers employed in this field is
constituted by leathers obtained by means of spreading technique,
generally multi-layered, for example based on polyurethane (PU) or
plastisol based on polyvinyl chloride (PVC), these latter also known in the
field as vinyl leathers.
The market often requires the synthetic leathers used to be of a
dark colour, normally black, and the leathers therefore have added to them
pigments capable of absorbing the greater part of luminous radiation in the
visible spectrum. The pigment more commonly employed in the field is
carbon black, which is added to one or more of the layers constituting the
synthetic leather.
These leathers, however, have some drawbacks, the main one being

constituted by the fact that, because of the dark or black coloration, they
tend to overheat when exposed to solar radiation, reaching relatively high
temperatures within a short time. In the case of synthetic leathers
employed as covering for saddles for bicycles or motor cycles or for seats
in motor vehicles, this situation occurs particularly frequently during the
summer months, and is particularly unpleasant in as far as the synthetic
leather comes into direct contact with the human body.
In the field of processing of natural leathers, it is known to use
particular pigments capable of absorbing a large part of the luminous
radiation in the visible spectrum, therefore imparting to the leather a black,
or at least dark, coloration and, at the same time, of reflecting a large part
of the infrared radiation, responsible for the heating of the leather.
European Patent Application No. 1553225 also describes the use of
pigments of the type described above in an artificial leather obtained from
polyester microfibre.
However, the use of natural leathers or leathers based on microfibre
generally proves too expensive and often not very suited to the specific
applications in which the synthetic leathers obtained by spreading are used
at present.
Description of the invention
The problem underlying the present invention is that of producing a
synthetic leather structurally and functionally designed to overcome the
limitations described above with reference to the prior art cited.
This problem is solved by the present invention by means of a
synthetic leather produced in accordance with the following claims.

Brief description of the drawings
The characteristics and advantages of the invention will become
clearer from the detailed description of a preferred exemplary embodiment
thereof, illustrated by way of non-limiting example with reference to the
appended drawings, in which:
Figure 1 is a diagrammatic view in section of a synthetic leather
produced according to the present invention,
Figure 2 is a diagram representing the course of the reflectance in
dependence on the wavelength of the electromagnetic radiation of a
leather produced according to the prior art,
Figure 3 is a diagram analogous to that shown in Figure 2 but
relating to the synthetic leather of Figure 1,
Figure 4 is a diagram analogous to that of Figure 2, but relating to
an alternative embodiment of the synthetic leather of Figure 1,
Figure 5 is a diagram analogous to that of Figure 2, relating to the
synthetic leather which is the subject of the diagram of Figure 4, but
in a different state of analysis.
Preferred way of implementing the invention
In Figure 1, a synthetic leather produced according to the present
invention is indicated as a whole by 1.
On the leather 1 an outer surface 2 is defined which, in the final
application of the leather, is intended to be facing outwards, and therefore
in view. A preferred example of application of the leather 1 is that of
covering for bicycle or motorcycle saddles, but other applications are of
course included, such as coverings for seats, steering wheels or other

vehicle accessories in general.
The leather 1 comprises a plurality of superposed layers obtained by
means of the technique of spreading a polymeric material suitable for this
type of processing.
Polymeric materials of this type may be polyurethane-based or,
preferably, based on polyvinyl chloride (PVC) plastisol, this term being
intended to identify a PVC-based polymeric mixture produced by means of
polymerisation in emulsion and suitably dispersed in a phthalic-based
plasticiser or in other plasticisers known in the field.
The leather 1 comprises, at the outer surface 2, an outer layer 3,
very thin and substantially transparent, capable of conferring on the
leather 1 the properties of feel, resistance to abrasion and surface finish.
The outer layer 3 is preferably obtained by spreading a polymeric material
based on polycarbonate, polyurethane or acrylic resin dissolved in an
organic solvent, such as toluene, methylethylketone (MEK),
dimethylformamide (DMF), or alcohols, in an amount of around 20 g/m2.
The leather 1 further comprises a first layer 4, coupled to the outer
layer 3 on the opposite side from the outer surface 2, and in which is
dispersed an effective amount of pigments capable of imparting a
coloration to the leather 1. Preferably, the coloration is dark, for example
in the dark shades of blue, red, green or grey, and even more preferably
the coloration is black.
The first layer 4 is preferably obtained by spreading a PVC plastisol
having a K value of between 72 and 80, dispersed in 90 phr of phthalic
plasticiser and stabilised with inorganic salts based on barium and zinc, in

an amount of around 250-400 g/m2.
Advantageously, the pigments dispersed in the first layer 4 are of
the type with high infrared radiation reflectance, that is to say, pigments
capable of reflecting a high fraction, at least 40%, of the infrared radiation,
in particular of the near infrared, and at the same time of absorbing a high
fraction, at least 80%, of the luminous radiation in the visible spectrum.
An example of such pigments is described in detail in European
Patent Application No. 1553225, the content of which is expressly claimed
herein. The quantity of pigment employed is between 3% and 10%,
preferably around 5%.
The leather 1 further comprises a second layer 5, coupled to the first
layer 4 on the opposite side from the outer surface 2. The second layer 5 is
obtained by spreading a PVC plastisol fully analogous to the plastisol of the
first layer 4, in an amount of around 200-400 g/m2. The second layer 5,
differing from the first layer 4, comprises an effective amount of light-
coloured pigment, preferably white, reflecting the radiation both in the
visible spectrum and in the region of the near infrared. A preferred
example of pigment dispersed in the second layer 5 is constituted by
titanium dioxide, present in the second layer 5 in an amount of between
5% and 20%, for example around 7.5%.
The leather 1 further comprises a third layer 6, coupled to the
second layer 5 on the opposite side from the outer surface 2. The third
layer 6 is obtained by spreading a PVC plastisol having a K value of
between 70 and 75, dispersed in 80 phr of phthalic plasticiser, stabilised
with inorganic zinc salts, and filled with calcium carbonate and crosslinked

with isocyanate, in an amount of around 100-300 g/m2. The third layer 6
has a substantially adhesive function and serves to couple, on the opposite
side from the second layer 5, a layer of textile 7, for example of polyester
fibre. Preferably, the textile layer 7 is of a light colour, and most
preferably white.
The textile layer 7 acts as a support for the polymeric layers
indicated above and its presence is necessary when the leather 1 is
subsequently to be coupled by means of stitching to the material covered
by it. This is the case, for example, with synthetic leathers used as
covering for motorcycle saddles, in which the leather must be stitched onto
the underlying padding, made for example of expanded polyurethane.
In other types of applications such as, for example, saddles for
bicycles, the material constituting the padding, for example a polyurethane
gel, is injected into a die, on the walls of which the covering synthetic
leather is arranged. In this case the leather 1 does not provide the textile
layer 7 nor the third adhesive layer 6, but only a thin layer (around 40-50
g/m2) of polyurethane in solvent as primer.
The leather 1 is obtained by means of a spreading process which is
conventional per se. The first step comprises the spreading of the outer
layer 3 on a papery support and drying thereof in an oven, after which, on
the only just dried outer layer the first layer 4 is spread, which is then
dried and following on, in a similar manner, the second layer 5 is spread
and, if required, the third layer 6 and the textile layer 7. At the end of the
spreading process and before the leather 1 is applied to the article to be
covered, the papery support is removed.

Some samples of synthetic leathers prepared as described
hereinafter were subjected to spectrophotometric analysis according to
standard ASTM E 903-96, so as to detect the course of the reflectance of
the different leathers in dependence on the wavelength of the radiation to
which they are exposed.
All the samples were of course irradiated on the side corresponding
to the outer surface.
Sample 1
Sample 1 represents a leather produced according to the prior art,
comprising a layer of PVC plastisol, having characteristics analogous to
those indicated above with reference to the first layer 4, but in which
carbon black was dispersed as pigment in order to obtain the dark
coloration of the leathers. The diagram resulting from the analysis is
shown in Figure 2, together with the precise reflectance value recorded at
980 nm.
Sample 2
Sample 2 was produced as described above with reference to the
leather 1, with the pigment of the first layer 4 coloured black, providing
also all the layers indicated above, as well as the textile layer 7, of a light
colour. This represents the preferred exemplary embodiment of the
present invention. The diagram resulting from the analysis is shown in
Figure 3, together with the precise reflectance value recorded at 980 nm.
Sample 3
Sample 3 differs from the preceding sample 2 in that it does not
provide the second layer 5, in which the white pigment is dispersed.

Sample 3 was subjected to analysis in two different operating states.
In the first case the sample was spread out on a light-coloured support
(diagram of Figure 4), while in the second case it was spread out on a
dark-coloured support (diagram of Figure 5). Both Figures 4 and 5 further
indicate the precise reflectance value recorded at 980 nm.
As may be observed from the results of the analyses, the leather
produced according to the prior art has a reflectance of less than 10% both
in the visible spectrum and in the region of the near infrared, as might be
expected.
With a leather of this type, therefore, the great majority of the
infrared radiation is transmitted through the leather or is absorbed by
same, causing the known drawback of overheating.
Samples 2 and 3, however, exhibited a decidedly better behaviour.
In fact, while maintaining a low reflectance in the visible field, necessary
for imparting the dark coloration to the leather, they reflect a significant
fraction of the infrared radiation, which will therefore not heat the leather
or any underlying padding.
Surprisingly, more detailed examination of the results of the
analyses shows that the performances of the different samples on the
other hand differ significantly from one another. In particular, it will be
noted that sample 2, provided with a layer with white pigment and also
with light-coloured fabric, has an optimum reflectance of around 73.5%, as
a against a maximum reflectance of around 58% in the case of the
absence of the layer with white pigment.
It should further be noted that in the case of the absence of the

layer with the white pigment, the colour of the support on which the
sample to be analyzed is deposited also assumes importance, inasmuch as
when changing from a light-coloured to a dark-coloured support the
reflectance drops from around 58% to around 41%. On the other hand,
the presence of the layer with white pigment renders substantially
negligible the coloration of the support on which the sample is deposited
during analysis.
The results therefore highlight the importance of the provision in the
multi-layer structure of the synthetic layer according to the invention of a
layer capable of reflecting the infrared radiation, constituted to some
extent by the light-coloured textile and, in particular, by the layer with the
white pigment. That layer therefore has the function of reflecting a large
part of the infrared radiation not reflected by the pigments with high IR
reflectance that are present in the first layer. The polymeric material
constituting the different layers of the leather is in fact substantially
transparent to infrared radiation.
The presence of the layer of white pigment and/or of the light-
coloured textile therefore advantageously makes it possible to avoid
overheating, not only of the synthetic leather, but also of the material to
which the leather itself is applied.
Particularly important and typical is the case of polyurethane
paddings used for saddles for bicycles, motorcycles and vehicles in general,
which absorb a considerable part of the infrared radiation and which would
therefore tend to overheat and to heat the synthetic leather by conduction.
It should further be noted that such layer may conveniently be light-

coloured or white, without altering the colour of the leather as perceived by
the user when examining it on the outer surface, which is normally the only
visible one, inasmuch as this layer is always hidden by the first layer
containing the high-reflectance coloured pigments.
The present invention therefore solves the problem mentioned
above with reference to the prior art cited, at the same time offering
numerous other advantages, including the fact that, by avoiding
overheating of the synthetic leather, its service life is also extended, owing
to the slowing down of the normal ageing processes.

CLAIMS
1. A synthetic leather (1), wherein an outer surface (2) is
defined. Intended, in use, to be facing towards the outside of an article
covered with said, leather (1), said leather comprising a plurality of
superposed layers of polymeric material, obtained by spreading, at least a
first of said layers (4) comprising one or more pigments capable of
imparting a dark coloration to said leather, and having, overall, a
reflectance to radiation in the region of the near infrared of more than
40%, characterized in that a second layer (5, 7) is provided, arranged on
the opposite side from said outer surface with respect to said first layer,
. comprising one or more pigments capable of imparting a light coloration to
said second layer.
2. A synthetic leather according to claim 1, wherein said second
layer is a support textile (7) for said layers of polymeric material.
3. A synthetic leather according to claim 1, wherein said second
layer is one of said layers (5) of polymeric material.
4. A synthetic leather according to one or more of the preceding
claims, wherein said second layer comprises an effective amount of
titanium dioxide.
5. A synthetic leather according to claim 4, wherein said second
layer comprises an amount of titanium dioxide of between 5% and 20% by
weight.
6. A synthetic leather according to one or more of claims 3 to 5,
wherein said first and said second layer of polymeric material are based on
polyurethane or polyvinyl chloride.

7. A synthetic leather according to claim 6, wherein said first and
second layer are obtained by spreading plastisol based on polyvinyl
chloride produced in emulsion dispersed in a phthalic plasticiser.
8. A synthetic leather according to one or more of the preceding
claims, wherein said pigments contained in said first layer are black.
9. A saddle for bicycles or motorcycles, comprising a covering
including a synthetic leather, characterized in that said synthetic leather is
according to one or more of the preceding claims.
10. A seat for motor vehicles, comprising a covering including a
synthetic leather, characterized in that said synthetic leather is according
to one or more of claims 1 to 8.

A synthetic leather (1) comprises a plurality of superposed layers of polymeric material, obtained by spreading, in at
least one (4) of which are dispersed one or more pigments capable of colouring the leather, preferably of a dark colour. The pigments
have overall a reflectance to radiation of the near infrared of more than 40%.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=VawYYw/F39ogOBT1OtyeKA==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 272598
Indian Patent Application Number 1493/KOLNP/2008
PG Journal Number 16/2016
Publication Date 15-Apr-2016
Grant Date 12-Apr-2016
Date of Filing 11-Apr-2008
Name of Patentee SPAC S.P.A.
Applicant Address VIA VI STRADA, 45-I-36071 ARZIGNANO (VI)
Inventors:
# Inventor's Name Inventor's Address
1 BEDESCHI EDOARDO VIA CORLANZONE, 10/B-30040 ALONTE (VI)
2 BEDESCHI GIULIANO VIA CORLANZONE, 10/B-30040 ALONTE (VI)
3 BEDESCHI GIOVANNI VICOLO VOLTO CITTADELLA, 8-37122 VERONA
PCT International Classification Number D06N 3/00,B62J 1/18
PCT International Application Number PCT/EP2006/004421
PCT International Filing date 2006-05-11
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 PD2005A000332 2005-11-15 Italy