FIELD OF THE INVENTION
[01] In a general way, the herby invention belongs to the technological sector of protection
industrial footwear and refers, more specifically to a fabrication process of safety footwear
with mono or dual density outsole, in Expanded Polyurethane (EP) of Polyester and Polyether
kind injected directly on the upper, or glued, for purposes of electric isolation.
BACKGROUND OF THE INVENTION
[02] Currently, the commercialization of professional footwear in Brazil (destined to security
and occupational health) demands the approval certification (AC), issued by the special
Bureau of Work at the Ministry of Economy. For that purpose, the footwear must attend to
requirements pre-established by the technical norms ABNT NBR ISO 20344, for the
methods, and also by ABNT NBR ISO 20345 and ABNT NBR ISO 20437 for the results.
Therefore, each product is destined to a determined risk field, indicated by norms throughout
the Regulatory Norm number 6.
[03] However, the traditional known process for the production of that kind of footwear, for
attending the current norms, winds up stumbling into clear technical issues, especially
towards the quality of the produced work, such as air bubbles within the outsole, variation of
size of the footwear in the same fabric process, variation in the work relationship,
imperfections of the contact with the skin of the Expanded EP, among others.
[04] Traditionally, for security footwear with electric isolation, the Whole Flexible
Polyurethanes (isocyanate and polyol), in which the most employed system in outsoles result
in a chemical exothermic reaction, freeing heat and altering the initial properties of the
reagents. The resulting product of these reactions goes then through a healing process.
[05] Based on that, this hereby invention purposed an innovative process, which includes the
joint application of the resin of the resin of Polyester or Polyether Polyurethane (Polyol),
adding to it a percentage of Modified Silicon Polymer, which guarantees a process of spilling
or injection meaningfully more effective and regular, making an innovating technical effect
concerning the known technologies in the current state of the technique.
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[06] The ingenuity of the hereby purposed process is clear when compared to the alternatives
that represent the current status of the technique, such as the case of BR102016019981-6
patent, entitled “PROCESS OF HEELS FOOTWEAR FABRICATION WITH
INJECTED OUTSOLE AND RESULTING FOOTWEAR WITH INJECTED
OUTSHOE” which reveals a fabrication process of heels footwear from the molding of the
outsole throughout the process of injection in the upper (1) of the shoes containing profiles
of internal reinforcement (4)(5). Such injection process of polymeric material comprises first
of all the development of an Aluminum cast, appropriate for the outsole injection (2)(8), and
appropriate material that offers the necessary structure to sustain the footwear heel. In the
production process purposed, the profiles of internal reinforcement (4)(5), which is put on
the cast to get the outsole injection (2)(8). The use of the direct injection process of the
outsoles (2)(8) to the uppers (1) of the footwear improves the product production .This fact
is reached, given that a substantial reduction of the labor, as well as the steps involved in the
manufactured process currently used and, consequentially, impacts directly on the costs of
the process and subsequent acquisition of the resulting products.
[07] However, as it can be seen, the previously quoted doesn’t point at an inclusion of the
additional Modified Silicon Polymer, purposing a process of injection of traditional
polymeric material in an Aluminum cast and doesn’t solve the previous attached problems,
which the hereby invention aims to resolve.
[08] There is also the invention patent PI 1000438-6, entitled “CONDUCTIVE,
RESISTIVE AND AGAINST TRIBOELECTRIC CHARGE FOOTWEAR AND
FABRICATION METHOD OF A CONDUCTIVE, RESISTENT AND AGAINST
TRIBOELECTRIC CHARGE FOOTWEAR” which reveals a conductive, resistive and
against triboelectric charge footwear that englobes a body or footwear cut, a semiconductor
outsole, a conductive resistive and against triboelectric charge insole, a common insole, a
bottom or outsole that has at least one portion that occupies the totality of the plant in contact
with the soil done with the same material as the unloaders and the semiconductor insole and
the unloaders whose goal is to connect the human body to the land and achieving the
liberation of the accumulated static charge, over which is fixated the outsole body,
characterized by the fact that the unloaders overtake the common insole and the footwear
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bottom, connecting the resistive insole and the soil throughout at least the portion or the
whole outsole when the latter is conductive resistive, and the fabrication method of the same.
[09] With that, starting from all the inconvenient features existent in the currently used
systems and equipment, described above in the status of the technique, it is clear that there is
a gap in the creation of a fabrication process of safety outsole in the creation of a fabrication
process of safety footwear with mono or dual density outsole, in Expanded Polyurethane (EP)
of Polyester and Polyether kind injected directly on the upper, or glued, with purpose of
electric isolation that solves the industrial and fabric problems such as air bubbles within the
outsole, variation of sizes of the footwear in the same fabric process, variation in the work
relationship, imperfections of the contact of the skin with the Expanded EP, among others.
NOVELTY AND GOALS OF THE INVENTION
[010] The hereby invention purposes an innovative process, which includes the continuous
application of the resin of Polyester Polyurethane or Polyether (Polyol) with a percentage of
the Modified Silicon Polymer in the fabrication itself resin of Polyester Polyurethane or
Polyether, whereas it guarantees a process of spilling or injection meaningfully more efficient
and regular, making an innovative technical effect to the known technologies in the current
technique status.
[011] Initially a Modified Silicon Polymer and Polyol mixture is obtained or the Resin of
Polyol Polyester or Polyether is used with the Modified Silicon Polymer, already added in
its fabrication itself, whereas is must be spilled on open casts (for spilling) or sealed (for
injection). From that point on, the process can develop into the confection of a mono density
outsole, obtained by the injection or spilling of only one kind of formulation of raw material
in a pre-heated cast or duel density, which means, the injection or spilling of two distinct
formulations of raw material.
[012] With the goal of curing the flaws of the current technique status above, this hereby
patent of invention aims to purpose a solution for the process of footwear fabrication with
outsoles of mono or dual density, in Expanded Polyurethane (EP) material of Polyester and
Polyether kind injected directly on the upper, or glued, with goals of electric isolation.
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DESCRIPTION OF THE ATTACHED DRAWINGS
[013] For this hereby invention to be fully understood and taken into practice by any
technician in this technological field, it will be described in a clear, concise and sufficient
way, having as a base the attached drawings listed below, that illustrate and subside it:
Picture 1 represents a flow chart of Formulated Polyol production in the security footwear
factory;
Picture 2 represents a flow chart of the security footwear production process;
Picture 3 represents the Mono density footwear kind;
Picture 4 represents the dual density footwear kind; and
Picture 5 represents a flow chart of insulator Polyol production, already with the Modified
Silicon Polymer.
DETAILED DESCRIPTION OF THE INVENTION
[014] So that the quoted process is perfectly understood and taken into practice by any
professional with a knowledge on the subject, it will be, from now on, described based on its
steps.
[015] Initially, a first preparation process must be executed, in which the Modified Silicon
Polymer must be added to the resin of Polyester or Polyether (Polyol), with initial free density
above 0,45, in a proportion that may vary between 0,15% to 1.50%, along with the other
needed additives, described below, on chat 1, for the reaction of expansion of the polymer
when added to the mixture of the components Isocyanate and Polyol, whereas the
achievement of an homogeneous mixture is an essential factor for the footwear fabrication
with ultimate performance.
Polyol Polyester or Polyether 88%-90%
Glycol Ethylene 9%-10%
Surfactant Agent 0,50% - 1.50%
Tertiary Amines 1,00% - 3,00%
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Modified Silicon Polymer 0,15%-1,50%
Chart 1 – Formulation of Polyol with Modified Silicon Polymer
[016] – Is it also needed to consider that, for an appropriate incorporation of the Modified
Silicon Polymer to the resin of Polyurethane Polyester or Polyether (Polyol), the following
parameters must be respected: (I) “Cowler” shaker kind with rotation between 1500-2000
RPM; (II) Time of agitation: 20 minutes minimum – 30 minutes maximum; (III)
Temperature: above 20°C; (IV) relative humidity: below 70%.
[017] There are two distinct ways of accomplishing the addition of the Modified Silicon
Polymer to the resin of Polyol Polyester or Polyether. One way is to add additives of reaction
to Polyol Polyester or Polyether. In that option the Modified Silicon Polymer will be added
along with the other additives of initial and final reaction (tertiary amines) on the resin of
Polyol Polyester or Polyether. Another way is adding on the fabrication of the Resin of Polyol
Polyester or Polyether. In that case, it is possible to achieve the Polyol Polyester or Polyether
with the Modified Silicon Polymer already in its formulation, not being necessary to add it
afterwards as quoted in the previous process.
[018] For this process, the following parameters should be respected:
Step 1: In a 65-70 °C temperature, 90% of Polyol Polyester or Polyether is added to the
reactor; Step 2: When the temperature decreases to 60 °C, 9% Ethylene glycol (EC) is added;
Step 3: When the temperature decreases to 55 °C, adding 1% of Active Surface Agent; Step
4: When the temperature reaches 50 °C, one adds 0.15% ~ 1,50% of Modified Silicon
Polymer on the weight of the Formulated Polyol; Step 5: After the addition of all the products
quoted in the previous steps, the mixture process of the reactor must last 2 hours in a 55°C
temperature.
[019] From then on, the production process per se is initiated, which can move forward
throughout two distinct pre polymers, being the first one with Polyester, usually obtained by
the proportion 1:1 (formulated polyol/Polyester). Most of the raw material is solid or
semisolid in ambient temperature and forms a microcellular uniform product or the second
throughout Polyether, obtained by the proportion of 2:1 (formulated polyol/Polyether). The
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spilling is done with the raw material in ambient temperature and forms a microcellular
uniform product with whole skin.
[020] The equipment used is specific to produce EP machines, for electrician footwear, there
are also two types of molding machines: by spilling and by injection, that splits into rotating
(machines with fixated heads and mobile molds carriers of carousel kind) or stationary
(machines of mobile heads and fixated molds carriers).
[021] This equipment is made of two reservoir tanks (X and Y) inside of which are stored
the polymer in X and the polyol in Y. From these tanks (X and Y) come out the products for
volumetric bombs of precision, being taken into a mixture chamber from where they will be,
afterwards, spilled or injected onto the mold.
[022] The reaction of the pre polymer with the polyol is quick and exothermic and happens
in two possible ways: when one uses liquids with low ebullition point, like expander agent,
the generation of heat turns them into gases, making the product “grow” and increase its
volume or when one uses water as an expander agent. In that case, the reaction will produce
carbonic gas, promoting also the product volume increasing. In both cases the volume
increasing fills the empty spaces within the mold.
[023] Due to the flexibility in the choice of raw material, there are many kinds of formulation,
where one can obtain a great variety of products, with different physical, mechanical and
chemical properties.
[024] Ultimately, for the achievement of the outsole, it is possible to execute the molding
through spilling or injection. The molding is done by the RIM system – “Reaction Injection
Molding”, in which the chemical reaction happens within the closed mold at the same time
in which the component is being formed.
[025] In the first case, a pre polymer mixture is obtained and the polyol that must be spilled
onto open molds, which will be immediately sealed. In the second case, the mixture is
injected into previously sealed molds, in which the polyurethane must expand. The
unmolding time may vary from 2 to 4 minutes and the recommended outflow must not be
higher than 30g/s and higher than 120g/s.
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[026] From then on, the footwear confection process continues, which can also go through
two different paths according to the type of product one wishes to produce, Mono density
Process (A) being called like that because the footwear outsole is obtained by the injection
or spilling of only one kind of raw material formulation in a pre-heated mold. After the
unmolding time runs, the mold is open and the product is extracted. For the footwear
achievement, the mold tap is open and the product is extracted. For the footwear achievement,
the mold tap is replaced by a form with upper, or Dual Density Process (B) when happens
the injection or spilling of two distinct formulations of raw material in a process with the
following steps: first, one injects or spills the compact material, closing the pre-heated mold
with a specific tap. This step is responsible for sourcing the outsole base; second, after the
curing time, the spilling or injection of a second distinct mixture happens on the quoted base.
The mold is closed with a form with an upper. After the curing time, specific for this process,
one opens the mold and the footwear will be ready, whereas the adhesion resistance between
the layers must be measured at least 72 hours after the production.
[027] The Modified Silicon Polymer will be injected in the below part of the dual density
security footwear, better known as compact outsole, according to the following mixture
proportion (work relation) do Polyol with the Pre-Polymer: Pre-Polymer with 85-90 parts
and Polyol with 100 parts.
[028] After the injection of the Expanded PE system (Polyol plus Pre Polymer) on the
compact outsole, one will inject the upper part better known as inter sole. The injection time
between the compact outsole and the inter sole must be higher than 50 seconds and lower
than 150 seconds.
[029] It is important to highlight that the done pictures and description do not have the power
to restrict the execution forms of the inventive concept hereby purposed, but of illustrating
and making the conceptual innovations revealed in this solution understandable. Therefore,
the descriptions and images must be interpreted in an illustrative and non-restraining way,
with possible other equivalent or analogue ways of development of the inventive concept
here revealed and that don’t run from the spectrum of protection outlined in the purposed
solution.
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[030] In the hereby descriptive report we approached a fabrication process of security
footwear with mono or dual density outsole with purposes of electric isolation, injected
directly on the upper or sealed, with purposes of electric isolation according to the norm of
ABNT NBR 16603:201, provided with novelty, inventive activity, sufficient description,
industrial application and, consequentially, invested with all the essential requirements for
the concession of the pleaded privilege.

We Claim:
1. A fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation which comprehends the steps of injection or spilling on the
mold and molding of footwear with electric isolation characterized by understanding the
step of addition of the Modified Silicon Polymer to the resin of Polyester or Polyether
(Polyol), with free initial density superior to 0,45, in a proportion that may vary between
0,15% to 1,50%.
2. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to demand 1 and also characterized by the fact that
the addition of Modified Silicon Polymer to the resin of Polyol Polyester or Polyether can be
made throughout the addition of additives of reaction to Polyester Polyol or Polyether.
3. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to the demand 1, and also characterized by the fact
that the addition of the Modified Silicon Polymer to the resin of Polyol Polyester or Polyether
can be made in the fabrication of the resin of Polyol Polyester or Polyether.
4. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to demands 1 and 2, and also characterized by the
fact, for addition of the Modified Silicon Polymer to the resin of Polyester or Polyether
(Polyol) along with the other necessary additives, according to the following proportions:
Polyol Polyester or Polyether in a range between 88%-90%, Glycol Ethylene in a range
between 9%-10%, Surfactant Agent in a range between 0.50%-1.50%, tertiary amines in a
range between 1,00%- 3,00%, Modified Silicon Polymer in a range between 0.15%-1.50%.
5. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to 1 and 2 demands, and also characterized by the
fact that, for incorporation of the Modified Silicon Polymer into the resin of Polyurethane
Polyester or Polyether (Polyol), the following parameters must be respected: “Cowles” type
of shaker with rotation between 1500- 2000 RPM, time of agitation at a minimum of 20
minutes and maximum of 30 minutes, temperature above 20°C, relative humidity below 70%,
and non-determined atmospheric pressure.
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6. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to demands 1 and 3, and also characterized by the
fact that the addition of the Modified Silicon Polymer to the resin of Polyol Polyester or
Polyeter must be according to the following parameters: Step 1, in a 65-70 °C temperature,
one adds 90% of Polyol Polyester or Polyether to the reactor; Step 2, when the temperature
decreases to 60 °C, one adds 1% of active surface agent; step 4, when the temperature reaches
50 °C , one adds 0.15% ~1,50% of Modified Silicon Polymer on the weight of Formulated
Polyol; and step 5, after the addition of all the products mentioned in the previous steps, the
mixture process in the reactor must last 2 hours in a 55°C temperature.
7. The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to the previous demands and also characterized by
the fact that the resultant footwear is mono density or dual density.
8 The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to previous demands and also characterized by the
fact that Polyol is composed with Polyester, in the 1:1 proportion.
9 The fabrication process of safety footwear with mono or dual density outsole for the
purpose of electric isolation according to previous demands and also characterized by the
fact that Polyol is composed with Polyeternal, proportion of 2:1.