Patent Description:
Throughout history, humanity have had to struggle with various epidemics. Some of these epidemics led to millions of death, destroyed almost whole the cities and changed the course of history. Communication between people has become more accessible with the development of technology in today's world. This situation caused the virus which occurred in a region to spread more rapidly. While an epidemic took months to spread in the past, today, it has become capable of affecting millions of people in a few days.

Even if they do not approach the number of deaths caused by the old epidemics, Swine Flu, MERS and SARS are prominent pandemics worldwide in the last <NUM> years. For the first time, as a result of research conducted in a group of patients who developed respiratory symptoms (fever, cough, shortness of breath) in Wuhan sub-provincial city, China, in late December <NUM>, COVID-<NUM> was defined in January <NUM>. The epidemic was initially detected in those in the sea products and livestock market in this area. Then by transmitting from person to person, it has spread to other cities in Hubei province, especially Wuhan, and other provinces of the People's Republic of China and other countries of the world.

Today, with the COVID-<NUM> pandemic becoming global, people are worried about their health and safety and they are fighting this pandemic by taking various measures. The use of masks and gloves is one of them. The mask is a personal protective equipment that protects the person against dust and particles of physical, chemical and biological agents.

Surgical masks are also known as procedure mask, medical mask, or face mask and they were originally designed to be used by healthcare professionals during surgery and patient care to prevent bacteria transmitted through aerosol and liquid droplets in the user's mouth and nose. However, during the ongoing coronavirus pandemic, people other than healthcare professionals also benefit from these masks.

These surgical masks generally consist of a three-layer structure. Non-woven fabrics produced with the technology of SMS, SS, SSS etc. (S stands for spunbond, M stands for meltblown) are joined by adhesive bonding, ultrasonic welding or lockstitch method. Meltblown (obtained as a result of the melt blowing process) layer filters the entrance and exit of microorganisms.

COVID-<NUM> Pandemic has brought along an increase in the demand for surgical masks and people other than healthcare professionals have also started to use masks widely. The fact that the raw materials of these masks are limited as spunbond and/or meltblown creates a problem in terms of supply and there is a lack of capacity. Insufficient capacity, high cost, rigid structure of the products, being difficult to shape and lack of volume are of the problems in the state of the art. Especially the meltblown layer has a challenging production process and a sensitive structure.

In the state of the art, various patent studies on surgical masks have been found. One of them is the US patent numbered <CIT> with the title "Germicidal face mask". In this patent, a mask that will reduce the amount of bacteria and germs the user is exposed to is mentioned. The outer layer of the mask is processed with an antiseptic substance. It is stated that the processed layer can be a non-woven fabric such as spunbond, meltblown or their lamination.

The European patent numbered <CIT> with the title "Method for making an electrostatically charged face mask" is another patent on the subject. Masks for medical and surgical uses are considered. The filtration medium consists of two electrostatically charged layers. It can retain bacteria and particles up to <NUM> micron.

The US patent numbered <CIT> with the title "Nanofibre membrane layer for water and air filtration" mentions a membrane layer containing nanofibres to be used in water and air filtration. Membrane layer consists of polymeric nanofibers with an average diameter of <NUM>-<NUM>.

The US patent numbered <CIT> with the title "High elongation thermally bonded carded nonwoven fabrics" claims a process for producing high elongation, thermally bonded carded nonwoven fabrics that are suitable for use in absorbent products such as diapers and pads. It describes the use of high elongation polyolefin staple fibers and carding techniques to achieve significant elongation and tensile strength. The process avoids the need for elastomeric materials, thereby addressing cost and processing challenges associated with traditional methods. The resulting fabrics, with a basis weight of <NUM>-<NUM> grams per square yard, are reported to have high tensile strength and excellent elongation, offering both functional and aesthetic benefits.

The international patent numbered <CIT> with the title "Methods of forming fibrous filtration face masks" describes a face mask invention with a shaping layer designed to minimize surface fuzz. This layer uses nonwoven, thermally bonded fibers, including at least <NUM>% thermally bondable fibers and <NUM>% bicomponent fibers. The mask is manufactured using cold molding and pressing to shape and reduce surface fuzz while maintaining effective filtration.

It has been seen that studies encountered in the state of the art are insufficient for existing problems such as meltblown capacity insufficiency, cost, and difficulty in application in the final product. Except for spunbond and meltblown, there is a need for products that can be produced using different raw materials, have ease of application, low cost and high bacterial retention.

The purpose of filtration layers of the present invention and production process is to produce filter layers by supporting thermobond (thermally bonded) nonwovens with different structures such as bicomponent, viscose, trilobal fibers and electrospinning methods. With the process developed, filtration layers are created as an alternative to meltblown and spunbond products.

An advantage of process of the present invention is the ability to produce an effective nonwoven mask fabric that provides ease of application thanks to the combination of staple fibers with different properties with thermobond (thermally bonded) production technology.

Another advantage of the process of the present invention is that it can be used in combination with an electrospinning process. In this way, with nano-sized filaments, the BFE (bacterial filtration efficiency) value will be increased and light, soft and effective layers will be obtained.

In one embodiment of the present invention filtration efficiency is increased by using fibers with different cross-section structures such as trilobal.

Production speed, capacity, ease of application, ease of working with different raw materials, ease of stitching, combination of special fibers with a bulky structure and increase in functional properties are the advantages of the invention according to the state of the art and constitute other advantages.

The present invention relates to a production method for a nonwoven material suitable for use as a filtration layer, as defined in claim <NUM>.

In order to better understand the filter layers produced according to the present invention and the production process, the figures below will be used.

With the filter layers of the present invention, basically, it is aimed to create an alternative product for the meltblown filter layer and thus to avoid the problems existing in the state of the art related to meltblown. Based on this main purpose, the electrospinning method is also used and with nanosized filaments, light, soft and effective alternative layers with high bacterial filtration efficiency (BFE) are obtained.

By combining the filter layers of the present invention, preferably, a three-layer surgical mask (<NUM>) can be formed. Although the increase in the number of layers increases the protection, it will decrease the comfort. It can be single or multi-layered. By combining the filtration layers of the present invention, the section view of a three-layer mask obtained is given in Figure-<NUM>.

Three layers defined as outer texture (1a), medium filter texture (1b) and inner texture (1c) are generally formed by organizing staple synthetic, natural and regenerated, bicomponent and customized fibers with different cross section structures. The outer texture (1a) and inner texture (1c) consist of the thermobond non-woven layer, and the medium filter texture (1b) consists of a thermobond non-woven layer supported by nanofibers obtained as a result of electrospinning. Each layer of the said surgical mask (<NUM>) has a BFE value (bacterial filtration efficiency) in the range of <NUM>-<NUM>%. Particle penetration value is in the range of <NUM>-<NUM>%.

In Figure-<NUM>, there is a representative view of the setup where thermobond non-woven production takes place. In the thermobond non-woven production setup (<NUM>), in general, by blending staple synthetic, natural and regenerated, bicomponent and customized fibers with different cross section structures, non-woven is obtained by carding, dry laying and thermal bonding methods. When stepped as a process, it consists of the following stages and the flow chart of these stages is given in Figure-<NUM>.

The thermobond non-woven obtained as a result of the process that is given in the flow chart in Figure-<NUM> and performed in a representative setup as in Figure-<NUM> is used in the outer texture (1a) and inner texture (1c) of the surgical mask (<NUM>).

Detailed explanation of the stages of the thermobond nonwoven production process are as follows.

At this stage, in the fiber opening chamber (2a) in the form of a single or eight blend, staple synthetic, natural and regenerated bicomponent fibers and customized fibers with different cross-sectional structures are pre-opened, preferably mechanically, at rates in the range of <NUM>-<NUM>%. Then it comes to picker, mixer cylinders (2b) and it is sent to the fiber warehouse (2c).

The fibers opened at this stage come to the fiber warehouse (2c) and then to the feeding unit (2d). Here, different types and structures of fibers are mixed in the desired blend by airing. By the conveyor belt (2e), the fibers are sent to the feeding rollers (2f) and then laid on the weighing conveyor belt (<NUM>) for carding.

At this stage, the fiber mixture, preferably in the range of <NUM> / m<NUM>- <NUM> / m<NUM>, which comes with a balance conveyor belt (2f), is spread randomly by dispersing ±<NUM><NUM> in parallel and cross direction in a system consisting of cylinders (<NUM>) and drums (2i) organized in different diameters, different speeds, different directions, different technical equipment and it is directed to the belt system with different number of transfer cylinders. Equipment features to perform carding of cylinders (<NUM>) take values depending on variables such as structureinclination and placement of these equipment, rotation of the rollers, raw material fiber mixture, fiber denier-length values, and fiber morphological structure. Fiber properties should preferably be in the range of <NUM>-<NUM> denier and <NUM>-<NUM> lengths. Fibers can be synthetic fibers with mono or bicomponent components, polyester, polyamide, polypropylene etc., bicomponent synthetic fibers in polyethylene-polypropylene, polyester-copolyester etc. structures, different cross-section structures, synthetic fibers with different cross-section structures such as round-hollow-trilobal, and natural and regenerated fibers of viscose, cotton, etc. The selection of these fibers, their blending and mixing ratios are decisive in the parameters regarding the equipment properties of the cylinders (<NUM>).

At this stage, the carded web (2j) obtained as a result of the carding stage (<NUM>) is organized and assembled as a single texture on the transfer belt. The carded web (2j) is transferred between the oil-heated calenders. It is passed between hot smooth calender (<NUM>) and hot embossing calender (<NUM>) at temperature, pressure and speed values suitable for the fiber mixture. The carded web (2j) is calendered with temperature and pressure and fixed by means of thermal welding points and the carded thermobond non-woven (<NUM>) is formed.

The parameters vary according to the raw materials, with the temperature values in the range of <NUM>-<NUM> C<NUM>, the temperature difference between the calenders being ± <NUM> C<NUM> and the embossing calender (<NUM>) thermal bonding area being in the range of <NUM>-<NUM>%.

Details on obtaining the thermobond non-woven layer have been given above as a result of the steps of the fiber opening stage (<NUM>), the fiber feeding stage (<NUM>), the carding stage (<NUM>) and the bonding stage (<NUM>). In this process, it should be known that the visual in Figure-<NUM> is representative, the process can be completed with different equipment that will serve the same function or manually, and the expressions such as machine, unit, etc. in the descriptions and images are not binding. The thermobond non-woven obtained as a result of this process is used directly in the outer tissue (1a) and inner tissue (1c) of the surgical mask (<NUM>).

As a result of the process of the present invention, a layer with a bacterial filtration efficiency (BFE) in the range of <NUM>-<NUM>% is obtained. The high bacterial retention is the original part of the invention. Process parameters are very important to get effective results. In particular, the bonding stage (<NUM>) can be considered critical. At this stage, the carded web (2j) passes through the calenders and the thermal bonding process takes place.

The fiber scale that can be used in the fiber opening stage (<NUM>), which is the first stage of the process of the present invention, is quite wide. However, in the state of the art, the fibers that can be processed are limited with spunbonds and meltblowns. The ability to carry out the process with various fibers provides filtration layers with different functional properties.

Medium filter texture (1b) of the surgical mask (<NUM>) is supported by nanofibers unlike the outer texture (1a) and inner texture (1c). The mentioned nanofibers are formed as a result of the electrospinning process. Electrospinning is a method applied by drawing the polymer from a specially prepared solution using an electric field. With this method, one-dimensional nanostructures can be obtained. A representative view of a setup regarding the strengthening of the thermobond non-woven layer obtained as a result of the inventive process by electrospinning is given in Figure-<NUM>. As seen in Figure-<NUM>, integration of the thermobond non-woven layer obtained as a result of the process of the present invention into the electrospinning process is provided by a thermobond non-woven cylinder placed in the electrospinning process. Nanofibers obtained by electrospinning method are transferred to the thermobond non-woven layer in the opening roller (3f) and the thermobond non-woven layer reinforced with nanofibers is wrapped with a separate winder roller (<NUM>).

In the electrospinning setup (<NUM>) in Figure-<NUM>, a chemical solution is first formed from the polymer and natural extracts and taken into the injector. For electrospinning synthetic fibers, it is preferred that the concentration percentage is in the range of <NUM>-<NUM>%. The conductivity of the solution mixture (3b) should preferably be in the range of <NUM> - <NUM> / cm and the viscosity preferably in the range <NUM>-<NUM> cp. The solution mixture (3b) in the injector is given from the nozzle (3c) with the help of the injector pump (3a) and is exposed to high voltage by the high voltage generator (3e). The speed of the injector pump (3a), the speed of the mixer is preferably in the range of <NUM>-<NUM> rpm. As a result of high voltage, nanothreads with dimensions between <NUM>-<NUM> begin to form. With high voltage electro spinning method on the nonwoven layer in the opening roller (3f) placed after the distance (3d), the polymerized filaments are transferred, wrapped with the help of a winder roller (<NUM>) and the process is completed. In the electrospinning process, filament spinning of any synthetic, polyethylene, polypropylene, PVC, polyurethane or ester group raw materials suitable for polymerization can be performed. The appearance, touching, usefulness, bacterial filtration feature, biocharging properties and breathability are increased with natural extracts. In the electrospinning process, the distance (3d) is preferably changed between <NUM> and <NUM> to shape the nanofilament structure.

In the preferred structuring, only the medium filter texture (1b) is supported by the electrospinning process and nanofibers. However, it is possible to use thermobond nonwoven supported with nanofibers in other layers. The layers are combined with methods such as ultrasonic or lockstitch machines in the state of the art.

Claim 1:
A production method for a nonwoven material suitable for use as a filtration layer characterized by passing a fiber mixture through the following stages:
fiber opening stage (<NUM>), fiber feeding stage (<NUM>), carding stage (<NUM>)
and
bonding stage (<NUM>),wherein in the bonding stage (<NUM>), the carded web (2j) obtained from the carding stage (<NUM>) is delivered between internally oil-heated calenders passed between a hot smooth calender (<NUM>) and a hot embossing calender (<NUM>), calendered with temperature and pressure, fixed through thermal bonding points, and forming the carded thermobond non-woven (<NUM>) layer, with the temperature value ranging from <NUM>-<NUM> C<NUM>, a temperature difference between the calenders of ± <NUM> C<NUM> and the thermal bonding area of the embossing calender (<NUM>) being in the range of <NUM>-<NUM>%.