Method for manufacturing lightweight meltblown hot-melt nonwoven fabric containing hydrophobic nanosilica

Abstract

A lightweight meltblown hot-melt nonwoven fabric containing hydrophobic nanosilica, manufactured by the manufacturing method of the present invention, when interposed between adherends such as fabrics to perform an adhesive function, has the effect of saving about 10-50% in material costs and energy while ensuring uniform adhesive strength across sections, excellent peel strength, and good air breathability, even with the application of a smaller amount of adhesive resin than conventional hot-melt films. As a result, the fabric product employing the meltblown hot-melt nonwoven fabric are characterized by the prevention of overflow during an adhesive process and by the realization of lightweight and soft hand feel.

Description

Method for manufacturing lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano silica

[0001] The present invention relates to a method for manufacturing a lightweight meltblown hot-melt nonwoven fabric containing hydrophobic nano-silica, and more particularly, to a method for manufacturing a lightweight meltblown hot-melt nonwoven fabric containing hydrophobic nano-silica, which can secure uniform adhesive force, excellent peel strength, and good breathability while saving material costs and energy by using a hot-melt nonwoven fabric manufactured by a melt-blown method when bonding fabrics such as clothing, shoes, and bags by interposing an adhesive resin between them, even when applying a smaller amount of adhesive resin than a conventional hot-melt film.

[0002]

[0003] Recently, efforts to reduce manufacturing costs and improve quality have been underway in industries such as footwear, apparel, and bags, as well as in all industries requiring adhesives. These efforts are aimed at reducing or eliminating the labor-intensive sewing process. Consequently, by replacing sewing, which accounts for a significant portion of manufacturing costs, with adhesives, the goal is to increase per-person production and reduce process times, thereby reducing costs.

[0004] This bonding process involves applying a liquid adhesive to a substrate, such as fabric, and then drying it to evaporate any solvent or moisture, bonding the fabrics together. While this process offers the advantage of reducing process time and labor compared to sewing, to maximize cost savings, a process often employs a hot melt film (hereinafter referred to as "hot melt film") instead of a liquid adhesive, bonding the fabrics together using heat presses.

[0005] The above hot melt film is used in the industrial fields of shoes, clothing, and bags for the purpose of being environmentally friendly, convenient, and cost-saving. It can be manufactured from various thermoplastic resins such as thermoplastic polyurethane (TPU), polyamide, ethylene vinyl acetate (EVA), and polyester. Such hot melt film has good extrusion workability and is not only environmentally friendly because it does not use solvents, but it is also suitable for securing adhesion to various fabrics by selecting a material with excellent adhesiveness and touch.

[0006] However, since conventional hot melt films are usually manufactured with a thickness of 0.2 mm or more to ensure stable adhesiveness, when hot melt films are inserted between fabrics and heat pressed (No-Sew Press) is performed, overflow frequently occurs, and in addition, the fabric product as a whole becomes heavier and feels hard to the touch, and there is a disadvantage in that it does not keep up with the development trend toward increasingly lighter products.

[0007] These conventional hot melt films have the problem of being thicker than 0.2 mm, but when a heat press operation is performed with a thermoplastic hot melt film inserted between fabrics, the amount of hot melt film is biased toward the fabric with a larger hole diameter, resulting in no hot melt film at the adhesive interface, which ultimately causes poor adhesion.

[0008] That is, when bonding different types of fabrics, such as fabrics with large and small woven holes or fabrics with high and low yarn density, using a thermoplastic hot melt film, the hot melt film is excessively biased toward one side of the fabric due to heat and pressure, which means that the hot melt film melts and flows into the fabric with the large hole size or the fabric with the low yarn density, so that no hot melt film remains on the remaining bonding interface of the fabric.

[0009] In order to improve the above problems, the inventors of the present invention studied thermoplastic polyurethane hot melt films manufactured by a T-die extrusion method and a manufacturing method thereof in Korean Patent Publication Nos. 10-2014-0147631 and 10-2015-0005092, and patent No. 10-1938526 disclosed a thermoplastic hot melt film for shoes comprising a resin composition selected from thermoplastic polyurethane (TPU), ethylene vinyl acetate (EVA), polyamide, and polyester, containing 0.1 to 5.0 phr of nano-silica, so that when the yarn density of the fabric is high or low during heat press bonding (No-Sew Press), or even when the diameter of the fabric weaving hole is large or small, the hot melt film does not melt and is biased to one side of the fabric due to heat and pressure, but is evenly applied to the surface of the fabric. It was discovered that the adhesive strength of the hot melt film can be increased by distributing it.

[0010] In addition, in Patent Nos. 10-2057036 and 10-2440469, by mixing the nano-silica used in the above patents with surface-modified hydrophobic nano-silica, in addition to the advantages of the previous invention, it is possible to manufacture a hot melt film with a thinner thickness, which saves material costs and energy, and multi-press molding is possible, thereby improving productivity, and in addition, the fabric applied with this becomes lighter overall and softer to the touch, and the quality of the product is improved by improving the overflow phenomenon that was a problem in the bonding process.

[0011] Meanwhile, in the present invention, as a result of repeated research to improve the problem that when a conventional hot melt film is bonded to a fabric (adherent), the fabric becomes stiff and the bonding strength is not consistent for each bonding section, when an adhesive sheet in the form of a meltblown hot melt nonwoven fabric is used to bond a fabric, a method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica having a much softer feel and excellent bonding strength and uniform bonding strength for each bonding section despite being designed with a hot melt adhesive resin of lower weight was developed, thereby completing the present invention.

[0012] [Prior Art Literature]

[0013] (Patent Document 1) Republic of Korea Patent Publication No. 10-2014-0147631 (Published on December 30, 2014)

[0014] (Patent Document 2) Republic of Korea Patent Publication No. 10-2015-0005092 (Published on January 14, 2015)

[0015] (Patent Document 3) Republic of Korea Patent Publication No. 10-1938526 (Published on January 15, 2019)

[0016] (Patent Document 4) Republic of Korea Patent Publication No. 10-2057036 (Published on December 18, 2019)

[0017] (Patent Document 5) Republic of Korea Patent Publication No. 10-2440469 (Published on September 6, 2022)

[0018]

[0019] The purpose of the present invention is to provide a method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica, which secures a manufacturing process for a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica, so that when the hot melt nonwoven fabric manufactured therefrom is interposed between adherends such as fabrics and bonded, a uniformity of adhesive strength by section, excellent peel strength, and good breathability can be secured even with a smaller amount of adhesive resin applied than a conventional hot melt film, while reducing material costs and energy, and thereby preventing an overflow phenomenon during the bonding process and realizing a lightweight and soft feel of a fabric product.

[0020]

[0021] The method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica according to the present invention is characterized by comprising the following steps: a first step of extruding the adhesive resin from an extruder and then forming a melt-spun fiber into a melt-blown nonwoven web through a spinning nozzle; and a second step of trimming and winding the melt-blown nonwoven web.

[0022] According to a preferred embodiment of the present invention, the average diameter of the fibers forming the meltblown nonwoven web is 1 to 30 ㎛, and the basis weight of the hot melt nonwoven fabric is formed in a range of 10 to 300 g / ㎡.

[0023] In addition, the hydrophobic nano-silica includes at least one hydrophobic functional group selected from an alkyl group, a dimethyl group, a trimethyl group, a dimethyl siloxane group, and a methacryl group on the particle surface, and the hydrophobic nano-silica forms nano-silica aggregates and has an aggregate size of 100 to 1200 nm on average.

[0024] And the thermoplastic polyurethane (TPU) adhesive resin may contain 20 to 70 wt% of a biomass-based thermoplastic polyurethane resin manufactured by reacting a diol chain extender and diisocyanate with a biomass-derived polyol.

[0025]

[0026] When the lightweight melt-blown hot-melt nonwoven fabric containing hydrophobic nano-silica by the manufacturing method of the present invention is interposed between adherends such as fabrics to perform an adhesive function, it has the effect of saving about 10 to 50% of material costs and energy while securing uniformity of adhesive strength by section, excellent peel strength, and good breathability even when applying a smaller amount of adhesive resin than the existing hot-melt film, and therefore, the fabric product applying the melt-blown hot-melt nonwoven fabric has the advantage of preventing the overflow phenomenon during the adhesive process and realizing lightweight and soft feel.

[0027]

[0028] Figure 1 is a drawing showing the results of microscopic measurement of the surface of a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica according to the present invention.

[0029] Figure 2 is a drawing showing the results of measuring the surface of a typical TPU hot melt film using a microscope.

[0030]

[0031] Hereinafter, a method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica according to the present invention will be described. However, this is intended to be an example to the extent that a person having ordinary knowledge in the technical field to which the present invention pertains can easily carry out the invention, and does not mean that the technical idea and scope of the present invention are limited thereby.

[0032] In general, hot melt adhesives are melted by heat and applied, so they emit very little volatile organic solvents, meeting the requirements of eco-friendly adhesives. Recently, efforts to prevent global warming, in addition to the emission of volatile organic compounds that are harmful to the human body, have been institutionalized from an environmental protection perspective, and as part of these global efforts, the use of resins with low carbon dioxide emissions, i.e. low LCA (Life Cycle Assessment) values, is required.

[0033] The above hot melt adhesive is a solid at room temperature, but when heated, it melts into a fluid state, providing adhesive strength to the object to be adhered. When the molten hot melt adhesive is cooled, it returns to a solid form and regains cohesive strength. The adhesive strength is affected by the penetration effect, which increases the adhesive strength by allowing the liquid adhesive to flow into holes or irregularities on the surface. To effectively utilize this effect, the hot melt adhesive must have sufficient flowability when melted. Therefore, it is melted at a high temperature to ensure an appropriate viscosity.

[0034] Meanwhile, the nonwoven fabric manufacturing process is generally a three-step process of web formation → web bonding → processing, and is produced in the form of a sheet. The nonwoven fabric manufacturing method is divided into wet method and dry method depending on the web formation method, and can be divided into needlepunching method, thermal bonding method, meltblown method, spunlace method, and stitchbond method depending on the difference in web bonding method.

[0035] In the present invention, the lightweight meltblown nonwoven fabric manufacturing technology for applying a hot melt adhesive is a process in which a polymer capable of forming fibers with a thermoplastic resin is spun through a spinneret formed with hundreds to thousands of orifices (for example, 2,700 spinnerets are provided in a width of 1,700 mm, depending on the nozzle size), and the polymer extruded through the spinneret is in a molten state and is formed into ultra-fine fibers with a diameter of several microns by hot air sprayed at high speed from both sides of the spinneret, thereby forming a self-bonding nonwoven fabric by stacking them on a collection body. By combining this with a hot melt adhesive technology containing hydrophobic nano-silica, functions such as uniform adhesive strength, excellent peel strength, good breathability, and a lightweight and soft feel of the product are realized.

[0036] The meltblown nonwoven fabric described above can be spun into ultra-fine fibers compared to spunbond nonwoven fabrics, so it has excellent flexibility and can be made lightweight. In addition, the present invention has solved the problem of the easy formation of fusion of fine fibers, shot or fly shapes due to the pulling and thinning of molten resin with a high-temperature, high-speed fluid by establishing optimal conditions in the manufacturing process through numerous trials and errors.

[0037] Accordingly, the method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica of the present invention comprises a first step of manufacturing a hot melt nonwoven fabric using at least one adhesive resin selected from thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) containing hydrophobic nano-silica having a particle size of 1 to 100 nm in a range of 0.1 to 5 phr (Parts per Hundred Resin), extruding the adhesive resin from an extruder and then forming a melt-spun fiber through a spinning nozzle into a melt-blown nonwoven web; and a second step of trimming and winding the melt-blown nonwoven web.

[0038] The term 'nanosilica' generally used in the present invention refers to silica particles of 100 nanometers (nm) or less, which are primary particles smaller than the micrometer (㎛) unit in size, and 'hydrophobic nanosilica' refers to nanosilica particles to which a hydrophobic functional group is introduced to part or all of the surface. Conventional nanosilica particles have a hydrophilic surface, but the nanosilica of the present invention has a hydrophobic surface by introducing a hydrophobic functional group (lipophilic) through a separate surface treatment (or surface modification), so that the surface is hydrophobic, and thus the dispersibility is excellent, and the water resistance of the thermoplastic hot melt adhesive resin itself is reinforced, thereby increasing the tensile strength.

[0039] In addition, the 'nanosilica aggregate' used in the present invention refers to a state in which about 70% or more of the nanosilica primary particles are strongly aggregated together by physical and chemical action. The nanosilica aggregate is formed by multiple primary particles gathering together, and is in a state in which it is difficult to further separate the nanosilica aggregate into smaller independent entities (nanosilica particles) within the hot melt adhesive resin.

[0040] The lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica according to the present invention is manufactured by using one or more adhesive resins selected from thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA), wherein the adhesive resin contains nano-silica having a hydrophobic functional group on the surface in an amount of 0.1 to 5 phr (parts per hundred resin), and the nano-silica has a particle size (primary particle size) of 1 to 100 nm.

[0041] The hydrophobic functional group contained in the particle surface of the above nano-silica is at least one selected from an alkyl group, a dimethyl group, a trimethyl group, a dimethyl siloxane group, and a methacryl group, and the above nano-silica forms a nano-silica aggregate and has an aggregate size of 100 to 1200 nm on average, so that when this is bonded by a heat press operation (No-Sew Press), the adhesive resin constituting the lightweight melt-blown hot melt nonwoven fabric is appropriately distributed between the fabrics (adhesive interface), thereby providing uniform adhesive strength for each part (see Patent No. 10-2057036).

[0042] It was confirmed that when a hydrophobic functional group is introduced to the surface of the nano-silica particles contained in the melt-blown hot-melt nonwoven fabric of the present invention, the dispersibility of the nano-silica is improved, and the water resistance of the hot-melt nonwoven fabric is reinforced and the tensile strength is increased due to the hydrophobic function, thereby reducing the cutting phenomenon that may occur due to moisture in a molding process such as spinning or stretching, and improving the physical properties such as moldability.

[0043] The hydrophobic functional group that can be introduced to the surface of the above nanosilica particles may be an alkyl group, a dimethyl group, a trimethyl group, a dimethyl siloxane group, a methacrylic group, etc. For example, the nanosilica particles used in the meltblown hot melt nonwoven fabric of the present invention are obtained by controlling the temperature and pressure in the fumed silica manufacturing process and treating the nanosilica with an organosilane compound, thereby including a dimethyl group on the surface of the nanosilica particles.

[0044] The nanosilica particles to which the above hydrophobic functional group has been introduced have an OH group density of 1.0 OH / ㎚. 3 The following is preferable. The OH group density can be measured by a known method, such as reacting nano-silica particles with hydrophobic functional groups introduced with lithium aluminum hydride and measuring the molar absorbance (ε) of the OH group stretching vibration band in the free silanol group at 3750 cm using IR spectroscopy.

[0045] In the present invention, nanosilica particles having hydrophobic functional groups introduced exist in the form of nanosilica aggregates, which are dispersed in a hot melt adhesive resin in an aggregate state that is difficult to separate. The aggregates preferably have an average aggregate size of 100 to 1200 nm, and more preferably, an aggregate size of 200 to 500 nm.

[0046] When the size of the above hydrophobic nano-silica aggregates is 100 nm or more, the nano-silica is well dispersed, but when it exceeds 1200 nm, the thickening effect decreases, and many defective phenomena such as cutting occur during the molding process using an extruder. The size of the above nano-silica aggregates refers to the length in the longitudinal direction of the nano-silica aggregates, and can be commonly measured using a transmission electron microscope, etc.

[0047] And, it is preferable that the average diameter of the fibers (single fibers) forming the meltblown nonwoven web is 1 to 30㎛, and thus, a fabric product using the lightweight meltblown hot melt nonwoven fabric can exhibit a softer feel than a fabric product using the existing hot melt film.

[0048] In addition, the basis weight of the hot melt nonwoven fabric can be adjusted to a range of 10 to 300 g / ㎡ depending on the application to clothing, shoes, bags, etc., thereby reducing the amount of adhesive resin used in a hot melt film (thickness of 0.1 mm or more) containing conventional hydrophobic nano-silica under the same conditions to half. However, when the basis weight of the hot melt nonwoven fabric exceeds 100 g / ㎡, it is difficult to exhibit a breathable function that is clearly differentiated from the conventional hot melt film due to the fusion by the high temperature and high pressure heat press bonding process. However, this hot melt nonwoven fabric has the advantage of dramatically improving the overflow phenomenon of the adhesive resin according to the bonding process compared to the hot melt film, thereby improving the quality performance of the fabric product.

[0049] Therefore, when the lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica manufactured by the manufacturing method of the present invention is bonded between fabrics such as clothing or shoes by interposing an adhesive resin, by using the hot melt nonwoven fabric manufactured by the meltblown method, a smaller amount of adhesive resin is applied than the existing hot melt film, and a more uniform adhesive force, superior peel strength, and good breathability are secured, while material costs and energy costs for heat press work can be reduced by up to 50%, and the overflow phenomenon during the bonding process can be prevented, and the weight reduction and soft feel of the fabric product can be improved.

[0050]

[0051] FIG. 1 is a drawing showing the results of microscopic measurement of the surface of a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica according to the present invention, and more specifically, it is a drawing showing the results of microscopic measurement of the surface of a TPU hot melt nonwoven fabric of the present invention having a thickness of 0.5 mm and containing 1 phr of hydrophobic nano-silica containing dimethyl groups as hydrophobic functional groups on the surface and having an average particle size (primary particle size) of about 20 nm.

[0052] Figure 2 is a drawing showing the results of microscopic measurement of the surface of a typical TPU hot melt film, and more specifically, it is a drawing showing the results of microscopic measurement of the surface of a typical TPU hot melt film having a thickness of 0.5 mm, in which 1 phr of hydrophobic nano-silica containing dimethyl groups as hydrophobic functional groups on the surface and an average particle size (primary particle size) of about 20 nm are mixed.

[0053] As shown in the above Figs. 1 and 2, in the present invention, a lightweight meltblown TPU hot melt nonwoven fabric was manufactured through numerous experiments to improve the weight reduction and soft feel of a fabric product. As a result, the basis weight of the lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica in the range of 0.1 to 5 phr based on the TPU resin for the TPU hot melt nonwoven fabric was formed in the range of 10 to 300 g / ㎡, and the amount of TPU resin used under the same conditions was reduced by about 10 to 50 w% for the hot melt nonwoven fabric compared to the hot melt film, and it was confirmed that the overflow phenomenon during the heat press operation (No-Sew Press) was reduced, and for this reason, the weight reduction and soft feel of the fabric product can be realized.

[0054] In the case of TPU resin, as a method of mixing the above hydrophobic nano-silica, there is a method of mixing nano-silica with raw materials during resin polymerization and then polymerizing to manufacture a resin for hot-melt non-woven fabrics, or a method of preparing a master batch using nano-silica and then mixing this with TPU resin to manufacture a resin for hot-melt non-woven fabrics. In addition, in the case of EVA resin, it is convenient to use a method of preparing a master batch using hydrophobic nano-silica and then mixing this with each resin to manufacture a resin for hot-melt non-woven fabrics.

[0055] The present invention was applied by mixing hydrophobic nano-silica having a size of 100 nm or less to manufacture a hot melt nonwoven fabric, and it was confirmed that the adhesive strength was improved even with a small amount of 0.1 phr (parts per hundred resin) or more. If the content of the nano-silica exceeds 5.0 phr, the surface of the hot melt nonwoven fabric becomes opaque and the adhesive strength rather decreases. In addition, there is a concern that the physical properties of the adhesive resin may deteriorate, such as blooming, on the surface of the hot melt nonwoven fabric over time.

[0056] The present invention improves dispersibility and reinforces water resistance by mixing nano-silica containing hydrophobic functional groups (lipophilic) on the surface as described above when manufacturing a hot melt nonwoven fabric, thereby increasing tensile strength, thereby securing more uniform adhesive strength and superior durability than conventional hot melt films with a thinner thickness, while reducing material costs as well as energy costs when manufacturing fabric products using the same.

[0057] In addition, the hot melt nonwoven fabric can maximize the adhesive strength of the hot melt nonwoven fabric by ensuring that the hot melt nonwoven fabric is evenly distributed on the surface of the fabric without being melted to one side of the fabric by heat and pressure when the yarn organization density of the fabric is high or low during heat press bonding (No-Sew Press) or when the diameter of the fabric weaving hole is large or small, and prevents the fabric from becoming hard, and improves the overflow phenomenon caused by the hot melt nonwoven fabric interposed between the fabrics, thereby providing excellent adhesive performance, and furthermore, realizing lightweight and soft feel of the fabric product to which the hot melt nonwoven fabric is applied.

[0058] Meanwhile, the thermoplastic polyurethane (TPU) used in the present invention is obtained by polymerizing raw materials such as polyol and isocyanate and low molecular weight glycol as a chain extender. Examples of the polyol used here include polyester glycol, polyether glycol, polycaprolactone, etc., examples of the isocyanate include aromatic isocyanate, aliphatic isocyanate, etc., and examples of the low molecular weight glycol include 1,4-butanediol, etc. In addition, ethylene vinyl acetate (EVA), polyamide, polyester resin, etc. can be used as materials for hot melt nonwoven fabrics, but in the present invention, it was concluded that using a single or composite adhesive resin selected from thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) is more effective in terms of mixing property, dispersibility, and adhesive performance with hydrophobic nano-silica (see Patent No. 10-2057036).

[0059] In particular, the thermoplastic polyurethane (TPU) adhesive resin is manufactured by reacting a diol chain extender and diisocyanate with a biomass-derived polyol to ensure price stability by using a resource-recycling material that conforms to green technology due to its environmentally and human-friendly characteristics. By including 20 to 70 wt% of a biomass-based thermoplastic polyurethane resin, the TPU adhesive resin can secure properties such as excellent heat resistance, elasticity, uniform adhesive strength, and outstanding durability at the level of petroleum-based materials (see Patent No. 10-2440469). It was confirmed that these positive effects can be equally implemented in the lightweight meltblown hot melt nonwoven fabric of the present invention as well as in the existing hot melt film.

[0060] In the present invention, the biomass-derived polyol used to manufacture a biomass-based thermoplastic polyurethane resin is at least one vegetable oil derivative selected from soybean oil, castor oil, rapeseed oil, sunflower oil, cottonseed oil, sesame oil, coconut oil, corn oil, peanut oil, safflower oil, and palm oil. There is no particular limitation on the specific type of vegetable oil, but it is advantageous in terms of economic efficiency to use soybean oil and castor oil.

[0061] It was studied that the aliphatic diol used in the above biomass-based thermoplastic polyurethane resin polymerization process is preferably at least one diol selected from among ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol.

[0062] In the present invention, in manufacturing a thermoplastic polyurethane adhesive resin for hot melt nonwoven fabrics (TPU adhesive resin for hot melt nonwoven fabrics with a biomass content of 20 to 70%) containing a biomass-based thermoplastic polyurethane resin in the range of 20 to 70 wt%, a biomass-derived polyol and a petroleum-derived polyol are mixed in the range of 20 to 70 wt%: 30 to 80 wt%, respectively, and then a diol-based chain extender and diisocyanate are reacted to manufacture the resin, or 20 to 70 wt% of a biomass-based thermoplastic polyurethane resin manufactured by reacting a biomass-derived polyol with a diol-based chain extender and diisocyanate and a petroleum-derived polyol with a diol-based chain extender and diisocyanate are reacted to manufacture the resin. It can be manufactured by mixing petroleum-based thermoplastic polyurethane resin in the range of 30 to 80 wt%.

[0063] As described above, the method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica of the present invention changes the manufacturing process conditions for the existing meltblown nonwoven fabric according to the type of adhesive resin and the characteristics of the product. It consists of a first step of extruding at least one type of adhesive resin selected from thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) from an extruder, and then forming a melt-spun fiber into a meltblown nonwoven web through a spinning nozzle; and a second step of trimming and winding the meltblown nonwoven web.

[0064] At this time, it is preferable that the thermoplastic polyurethane (TPU) adhesive resin is melt-spun through an extruder at 130 to 200°C and a spinneret at 170 to 220°C, and that the ethylene vinyl acetate (EVA) adhesive resin is melt-spun through an extruder at 80 to 170°C and a spinneret at 130 to 200°C. Therefore, it is necessary to appropriately control the temperatures of the extruder and the spinneret within a given range depending on the type of adhesive resin.

[0065] Hereinafter, examples of experiments on lightweight meltblown hot melt nonwoven fabric (TPU resin) containing hydrophobic nano-silica manufactured by the present invention will be described. The present invention will be described through preferred examples that can be easily carried out by a person having ordinary knowledge in the technical field to which the present invention pertains.

[0066] [Example] Manufacturing of lightweight meltblown hot melt nonwoven fabric containing hydrophobic nanosilica

[0067] A. Polymer input: TPU resin containing hydrophobic nano-silica is made into small spherical or granular pieces and poured into a barrel or hopper to be fed into a screw extruder.

[0068] B. Melt extrusion: TPU hot melt resin chips are fed into a screw extruder and extruded at high temperatures to become TPU melt resin. Finally, the TPU melt resin is sent to the spinneret through a filter by a metering pump.

[0069] D. Fiber Formation: Clean TPU melt resin filtered through a filter is spun from the nozzle of each spinneret and sprayed evenly. Unlike other spinning methods, the melt-blown spinneret has spinneret holes arranged in a straight line, and there are high-speed air injection holes above and below the spinning nozzle.

[0070] A. Fiber cooling: A large amount of room temperature air is sucked in from both sides of the spinneret simultaneously, and the radiated TPU fibers are mixed with the hot air, so that the TPU hot melt nonwoven fabric is cooled and solidified.

[0071] Web Formation: In the production of meltblown TPU hot melt nonwovens, the spinneret can be positioned horizontally or vertically. When positioned horizontally, the spinneret sprays fibers onto a circular collecting drum to form a nonwoven web. When positioned vertically, the spinneret falls onto a horizontally moving web-forming curtain to form a nonwoven web.

[0072] Bar. Trimming and Winding: The produced TPU hot melt nonwoven fabric is trimmed to the desired width, wound, and packaged.

[0073] [Experimental Example 1]

[0074] In order to prove the effectiveness of the lightweight meltblown TPU hot melt nonwoven fabric containing hydrophobic nano-silica, the adhesive strength of the TPU hot melt nonwoven fabric manufactured as described above and the general TPU hot melt film was measured at each section.

[0075] ○ Test subjects

[0076] - NASA-WEB(TT): Lightweight meltblown TPU hot melt nonwoven fabric containing hydrophobic nanosilica

[0077] - General WEB: TPU hot melt film without hydrophobic nanosilica

[0078] ○ Test method

[0079] - Within a test piece measuring 15 cm in length and 1 inch in width, the adhesive strength is divided into 5 sections measuring 2 cm each, and the minimum adhesive strength is measured (this test method applies the NIKE METHOD G44 method).

[0080] ○ Test conditions

[0081] Product name Temperature / Time / Pressure Actual weight (g / ㎡) NASA-WEB (TT) 45g 125℃ / 20s / 45bar 42 General WEB 60g 109℃ / 30s / 45bar 62

[0082]

[0083] ○ Test results (adhesive strength: kg / cm)

[0084] 1. NASA-WEB(TT) 45g

[0085] NO Direction (L / W) MIN (A) MAX (B) GAP (BA) AVG (1~5) Section 1 Section 2 Section 3 Section 4 Section 5 Section 1L1.021.090.071.061.081.091.051.071.022L0.991.030.041.011.020.990.991.031.033L1.041.070.031.061.071.051.061.061.044L1.071.100.031.081.091.071.081.101.075L 1.061.110.051.091.111.061.091.101.106L1.001.040.041.021.011.001.031.021.047L1.111.150.041.121.151.111.1 11.121.128L1.061.090.031.071.091.081.071.061.079L1.071.120.051.101.101.121.111.121.0710L1.101.150.051.1 31.121.101.131.131.1511L1.001.040.041.021.011.001.031.021.0412L1.111.150.041.121.151.111.111.121.1213L 1.061.090.031.071.091.081.071.061.0714L1.071.120.051.101.101.121.111.121.0715L1.101.150.051.101.101.121 .111.121.0716W0.971.030.061.011.031.001.031.000.9717W0.971.060.091.031.041.061.051.010.9718W0.981.080.1 01.041.081.061.071.000.9819W0.961.050.090.990.980.980.960.971.0520W1.011.040.031.031.021.011.041.041.03

[0086]

[0087] 2. General WEB 60g

[0088] NO Direction (L / W) MIN (A) MAX (B) GAP (BA) AVG (1~5) Section 1 Section 2 Section 3 Section 4 Section 5 1L 0.810.910.100.880.910.880.910.870.812L 0.800.950.150.880.950.900.890.870.803L 0.800.930.130.870.930.930.860.800.814L 0.941.150.211.021.151.021.050.960.945L 0.781.020.240.881.020.910.840.780.866L0.941.010.070.980.970.981.001.010.947L0.871.040.170.950.960.920.9 81.040.878L0.830.970.140.920.950.920.970.940.839L1.101.180.081.131.181.121.131.101.1010L0.820.940.120.8 90.940.900.850.820.9311L0.991.100.111.031.031.021.101.020.9912L0.821.010.190.920.941.010.940.870.8213L 0.931.060.130.990.930.991.060.990.9814L0.961.060.101.011.061.021.011.010.9615L0.860.950.090.920.950.860 .900.950.9516W0.941.070.130.991.070.980.940.941.0217W0.941.020.080.971.020.940.990.970.9518W0.870.930.0 60.900.930.930.910.870.8819W0.920.990.070.960.920.960.950.990.9820W0.880.940.060.910.930.880.880.930.94

[0089]

[0090] As shown in the test results of [Table 2] above, it can be seen that the lightweight meltblown hot melt nonwoven fabric (NASA-WEB (TT) 45g) containing hydrophobic nano-silica has a minimum deviation of 0.03 kg / cm and a maximum deviation of 0.10 kg / cm in adhesive strength within one specimen. On the other hand, as shown in the test results of [Table 3] above, the TPU hot melt film (general WEB) not containing hydrophobic nano-silica has a minimum deviation of 0.07 kg / cm and a maximum deviation of 0.24 kg / cm in adhesive strength within one specimen. Therefore, it can be confirmed that the lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica of the present invention has excellent adhesive strength uniformity because the deviation of adhesive strength by section is smaller than that of the TPU hot melt film not containing hydrophobic nano-silica.

[0091] In addition, the fabric product using the lightweight melt-blown hot-melt nonwoven fabric containing the hydrophobic nano-silica has an average of 10% or more superior adhesive strength than a general hot-melt film even when using about 30% less adhesive resin, so that not only can material costs and energy be saved, but also the overflow phenomenon during the bonding process can be prevented, and the product can be made lightweight and have a soft feel. Furthermore, when bonding a functional fabric with a moisture-permeable and waterproof function, it is possible to apply a thin melt-blown hot-melt nonwoven fabric that can ensure good breathability.

[0092] [Experimental Example 2]

[0093] In order to prove the effectiveness of the lightweight meltblown TPU hot melt nonwoven fabric containing hydrophobic nano-silica manufactured as described above, the air permeability of the TPU hot melt nonwoven fabric manufactured as described above and a general TPU hot melt film was measured.

[0094] ○ Test subjects

[0095] - NASA-WEB(TT): Lightweight meltblown TPU hot melt nonwoven fabric containing hydrophobic nanosilica

[0096] - NASA-TT 30㎛: TPU hot melt film containing hydrophobic nanosilica

[0097] ○ Test method

[0098] - Measure the flow rate of air passing vertically through the test piece under conditions of a certain area, pressure, and time (KS K ISO 9237 method).

[0099] ○ Test results (air permeability: mm / s)

[0100] Product name Nonwoven fabric / film Single No-Sew After bonding Package NASA-WEB (TT) 30g 5460 ~ 6270 61.3 ~ 86.7 NASA-TT 30㎛ 36g 1 or less 1 or less

[0101]

[0102] As shown in the test results shown in the above [Table 4], the lightweight meltblown TPU hot melt nonwoven fabric (NASA-WEB(TT)) containing hydrophobic nano-silica has superior air permeability than the TPU hot melt film (NASA-TT 30㎛) containing hydrophobic nano-silica of similar weight, so it can be seen that the lightweight meltblown hot melt nonwoven fabric according to the present invention is easy to produce a breathable fabric product by controlling its thickness.

[0103]

[0104] Therefore, the lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica manufactured according to the present invention can be equally applied to industrial fields where existing hot melt films are applied, as it is interposed between adherends such as fabrics to perform an adhesive function. In other words, it can be substituted, modified, and changed in various forms within the scope that does not depart from the technical spirit of the present invention, and can be applied to various purposes and forms as an adhesive nonwoven web for various fiber, leather, and plastic products that require uniform adhesiveness and durability, such as fabric fields for various shoes, clothing, and bags, as well as sports goods, composite fiber structures, mobile device cases, electronic device housings, automobiles, and home interiors.

Claims

In manufacturing a hot melt nonwoven fabric using at least one adhesive resin selected from thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) containing hydrophobic nano-silica having a particle size of 1.1 to 100 nm in a range of 0.1 to 5 phr (Parts per Hundred Resin), A first step of forming a meltblown nonwoven web by extruding the above adhesive resin from an extruder and then melt-spinning the fiber through a spinning nozzle; A second step of trimming and winding the above meltblown nonwoven web; A method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica characterized by being composed of:

2. In paragraph 1, A method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica, characterized in that the average diameter of the fibers forming the meltblown nonwoven fabric web is 1 to 30 ㎛.

3. In paragraph 1, A method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica, characterized in that the basis weight of the hot melt nonwoven fabric is formed in a range of 10 to 300 g / ㎡.

4. In paragraph 1, A method for producing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nanosilica, characterized in that the hydrophobic nanosilica contains at least one hydrophobic functional group selected from an alkyl group, a dimethyl group, a trimethyl group, a dimethyl siloxane group, and a methacryl group on the particle surface.

5. In paragraph 4, A method for manufacturing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano silica, characterized in that the hydrophobic nano silica forms nano silica aggregates and has an aggregate size of 100 to 1200 nm on average.

6. In paragraph 1, A method for producing a lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica, characterized in that the thermoplastic polyurethane (TPU) adhesive resin comprises 20 to 70 wt% of a biomass-based thermoplastic polyurethane resin produced by reacting a diol chain extender and diisocyanate with a biomass-derived polyol.

7. A lightweight meltblown hot melt nonwoven fabric containing hydrophobic nano-silica manufactured by a manufacturing method according to any one of claims 1 to 6.

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