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SOFPRENE®
Sofprene®
is the trade name
of So.F.Ter.
compounds based on the SBS (Styrene-Butadiene-Styrene) block
thermoplastic elastomer.
SBS thermoplastic rubbers present high elastic properties thanks to
their particular block structure. The great commercial success of these
types of polymers is connected to the economic and easy processability
that allows the production of items with similar characteristics to
cured rubber avoiding the long and expensive curing processes. The wide
range of formulations developed by So.F.Ter. can meet any
requirements of customers operating both in the footwear and in the
technical sectors. The Sofprene grades specifically designed for the
footwear sector, have the first digit of the identification code
variable between 1 and 4.
CHARACTERISTICS
Sofprene® compounds are available in a wide range of hardnesses
from 40 to 85 Sh A units. The elastic behaviour is excellent at room
temperature and still very good up to - 40 °C. Maximum working
temperature is + 50 °C. Sofprene®
is a fully recyclable material
blended both with other Sofprene grades and with different polymers.
Provided it is properly stored, it does not require pre-drying phases
before processing.
PROCESSABILITY
The technologies which are commonly used for SOFPRENE processing are
injection moulding and extrusion - the latter only for the production
of rands. The injection process can be carried out with the extruder
type, controrotating screw extruder type or transfert type machines.
Using the proper machine it is possible to inject soles composed of 2
or 3 colours and/or inject directly onto upper.
The following suggestions are meant only as helpful information and are
subject to modifications in each single case according to the equipment
to be utilized. SOFPRENE is anyway one of the most easily processable
thermoplastic rubber compounds. For injection moulding it is
recommended to use standard screws with processing temperatures ranging
from 140 -160 °C in the first zone to 160-190 °C in the last
zone. The runners should be round-shaped, the shortest possible and
with gradually narrowing sectional areas of flow. A round-shaped
injection point is suggested, whereas a too small or film-shaped one
should be avoided.
Mould temperature is to be
kept within the 20-40 °C range and proper air vents from the cavity
should be provided for. Injection speed must be medium-high whereas
high injection pressures are not required. Shrinkages range from 0,4 to
1,2 % depending on the grades.
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The Division
deals with production, research and development and marketing of Sofprene® compounds; these
materials are blends based on SBS
(Styrene-Butadiene-Styrene) thermoplastic polymers able to meet the
different requirements of the shoe market.
The manufacturing
department is located at two different sites based in Forlì
and Sant’Elpidio a Mare (AP).
All compounding stages are handled and
checked by a computerized unit which guarantees on real time both the
right measuring of raw materials and the correct transforming
conditions.
To guarantee the higher possible quality level of Sofprene®
compounds, So.F.Ter.
carries out checks during all stages of the production cycle starting
from strict inspections on purchased raw materials down to a complete
analysis of the finished and ready-to-delivery granule.
In the shoe market, which is obviuosly strictly linked to the
“fashion factor”, being able to continuously propose new
materials and solutions to customers, designers and consequently to end
consumers is of fundamental importance.
Through a qualified pre/post sales structure, customers are guided and
driven to choose the right materials and their correct application at
any time of the collaboration relationship.
The
finished product is packed by means of a state-of-the-art packaging
system which guarantees constantly checked weights and the product
quality and stability in all the different kinds of transportation
used. Our efficient shipment division, thanks to the experience built
up in twenty years of activity, is able to meet any customers’
request guaranteeing an excellent service in all different geographical
areas of the world.
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SOFPRENE® FOR FOOTWEAR: main grades
Bases 101-109 and
47Q/47A: “Peach skin“
Expanded compounds with excellent physical-mechanical properties and
low density (up to 0,9 g/cc on the sole). Mainly utilized for soles
imitating the natural rubber “crepe”, they present the same
matt and homogeneous aspect without need of any sole finishings.
Base 18NM: MICROFOR “NM” light expanded
Microcellular expanded compound with low density (from 0,6 to 0,9 g/cc
on the sole), with rather good physical-mechanical properties and a
very good rubber-like surface aspect. This compound is easy to be
injected and suitable to the moulding of many types of soles - also
two-coloured soles. Best results in terms of lightness are achieved on
massive soles. Possible finishing operations are brushing, painting and
matt finishing.
Bases 320-329 and 47C-48L: semi-glossy compact
Standard compounds with semi-glossy surface aspect. These grades can
cover a wide range of physical-mechanical properties. It is suggested
to use the bases 320/322-47C for soles with a rather complex design or
which have to be sewn, whereas in case of simpler (flat) design it is
recommended to use the bases 323/329-48L which present a more
homogeneous surface aspect. These compounds are suitable to all
finishing operations.
Bases 240-249: glossy compact
Glossy compact compounds with excellent physical-mechanical properties
- especially abrasion resistance. Compared to the bases 320-329, the
surface aspect is more glossy, so that the sole might need a finishing
process: matt finishing or painting. These grades generally have a low
melt flow index.
Bases 360-369 and 47N-48H, 350-359 and 47L-48S, and
380-389: Rubber-like
This type of compounds imitates the aspect of cured rubber and has the
property of copying the mould - thus giving the moulded sole a matt or
glossy surface aspect depending on the surface finishing of the mould.
A “smooth” mould surface gives the sole a glossy aspect,
whereas a sand-blasted mould surface gives the sole a matt aspect.
Alternating these two types of finishings it is possible to obtain
soles with very refined and fashionable designs. These rubber-like
compounds have a different capacity of copying the mould. This property
improves from base 36 to 35 and even more to 38. Base 38 is especially
considered of “extra quality” as it combines a very matt
and homogeneous aspect with very good physical-mechanical properties.
All rubber-like materials can be utilized for the production of any
type of soles: leisure time, “fashion” and training soles.
Furthermore So.F.Ter. has developed a wide range of rubber-like
formulations for specific applications aimed at satisfying any market
requirements: direct injection onto upper, galoshes for snow-boots,
“boarder” fashion soles, galoshes for rainproof boots, and
high heel elegant soles. Together with the fashion-related aspect our
wide range of formulations allows us to offer to our customers
compounds with physical-mechanical properties of any level, even much
superior to the standard values listed in the table. All the finishing
operations are possible.
Bases 42 D and 47Y: extra quality similar-to-rubber
Similar-to-rubber compact compounds with a rather good capacity of
copying the mould surface, excellent physical-mechanical properties,
high transparency and low density. The most suitable application of
this compound is the moulding of “tractor tread”-like soles
having a critical design with respect to the sole repeated flex test.
Standard finishing operations are brushing and mill finishing.
Bases 199 and 48E: similar-to-rubber
Similar-to-rubber compact compounds with a rather good capacity of
copying the mould surface. Considering that these compounds combine a
matt and homogeneous surface aspect with a good fluidity, they are
successfully employed for high heel elegant soles to be eventually
painted.
Bases 220T and 47R: transparent
CGlossy compact compounds with high transparency and exceptional
physical-mechanical characteristics. Designed by So.F.Ter. to meet the
new requirements of the shoe market, these compounds are mainly used to
mould inserts or two-/three-coloured soles and are often combined with
the microexpanded MICROFOR “NM”.
Bases 410-419 AND 48F: semi-glossy economic
Semi-glossy economic compact compounds with good extrudibility and a
very good ratio Quality/Price.
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101-109
47Q-47A |
Peach Skin |
all |
700 |
170 |
20 |
0,95 |
0,4 |
18 NM
MICROFOR |
MicroExpanded
light |
all except crepe-like |
650 |
da 250
a 450 |
da 50
a 100 |
da 0.9
a 0.6 |
0 |
220T
47R |
Glossy
Transparent |
all |
900 |
150 |
15 |
0,93 |
1,0 |
320-322
47C |
Semi-glossy
compact |
all |
650 |
220 |
25 |
1,00 |
0,8 |
323-329
48L |
Semi-glossy
compact |
all except crepe-like |
500 |
220 |
35 |
1,00 |
0,6 |
| 240-242 |
Glossy
Compact |
all |
650 |
160 |
20 |
0,97 |
0,8 |
| 243-249 |
Glossy
Compact |
all except crepe-like |
500 |
160 |
30 |
1,00 |
0,6 |
199
48E |
Similar-to-rubber
compact |
all except crepe-like |
500 |
200 |
50 |
1,00 |
0,8 |
42 D
48 Y |
Similar-to-rubber
compact |
all |
750 |
200 |
40 |
0,95 |
1,0 |
360-362
47N |
Rubber-like
compact |
all |
700 |
200 |
35 |
0,98 |
1,0 |
363-369
48H |
Rubber-like
compact |
all except crepe-like |
550 |
190 |
50 |
1,00 |
0,8 |
350-352
47L |
Rubber-like
compact |
all |
750 |
200 |
35 |
0,97 |
1,1 |
353-359
48S |
Rubber-like
compact |
all except crepe-like |
550 |
190 |
45 |
1,00 |
0,9 |
| 380-382 |
Extra
Rubber-like
compact |
all |
800 |
190 |
35 |
0,94 |
1,2 |
| 383-389 |
Extra
Rubber-like
compact |
all except crepe-like |
650 |
180 |
40 |
0,97 |
1,0 |
410-419
48F |
Econ.
semi-glossy
compact |
all except crepe-like |
450 |
220 |
40 |
1,01 |
0,6 |
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