KR102036685B1 - Manufacturing method of protective SFT using low density silica, protective SFT - Google Patents

Abstract

The present invention relates to a shear thickening solution used in protective clothing, such as a body armor and a sword suit, comprising the steps of synthesizing low-density hollow silica beads except for the calcination process, and modifying the surface of the hollow silica beads; Method for producing a shear thickening liquid for protection using low density silica, characterized in that it comprises the step of preparing a mixture of the surface-modified hollow silica beads and organic polymer particles and dispersing the mixture in a solvent Shear thickening solution for protection and protective material using the same are the technical points. Accordingly, the present invention is to prepare a shear concentrate using a hybrid mixture of low-density hollow silica beads and organic polymer particles to apply to protective clothing, excellent ballistic and anti-sword performance, excellent wearing comfort, lightweight protective clothing There is an advantage to providing a protective agent.

Description

Manufacturing method of protective shear concentrate using low density silica, low density silica, protective SFT

The present invention relates to a shear thickening solution used in protective clothing such as body armor and a sword suit, by producing a shear thickening solution using a hybrid mixture of low-density hollow silica beads and organic polymer particles to achieve excellent fit and light weight The present invention relates to a method for producing a protective shear thickening liquid using low density silica, a protective shear thickening liquid according to the same, and a protective material using the same.

Bulletproof and sword suits are used not only for the military but also for the recent use of personal shotguns, which are increasingly used for police and personal protection.

Conventional bulletproof and anti-sword suits have been using hard protective clothing using a ceramic panel and the like focused on the anti-ballistic and anti-sword effect, but there was inconvenience due to flexibility and heavy weight.

Recently, soft protective clothing made of fabric made of high-strength fibers is mainly used.However, in order to improve the protection effect, the soft protective clothing is increased in weight due to the multiple layers, and the flexibility is reduced, which affects the wearer's activity and comfort. It is becoming.

The soft protective clothing is mainly used aramid fibers and ultra-high molecular weight polyethylene fibers, but due to the limitation of the strength of the short-range and ultra-fast collisions, the buffer capacity is low, and there is a high price disadvantage. In addition, the physical properties of today's fibers have reached a limit, and these fibers alone are difficult to defend against the increasing protection.

As a method for solving this problem, there is a technique using a liquid bulletproof material using a shear thickening fluid (STF).

Shear thickening fluid (STF) is a fluid whose viscosity increases rapidly above the critical shear rate when small particles are dispersed in a high concentration in the liquid. It is known as a smart material that has a buffering effect by automatically responding to an external impact.

In other words, when the impact on the liquid ballistic material is impacted by using the properties of the shear thickening liquid, the shear thickening liquid in the liquid phase instantly becomes solid, and the coal is infiltrated. It does not affect the wearability to secure flexibility and can provide a light weight body armor than conventional body armor made of aramid fibers.

The body armor for the first time to apply the shear thickening technique is based on STF and Kevlar fabrics using 200 nm silica particles, which have the same anti-ballistic effect while reducing the number and thickness of Kevlar fabric by more than 50%. have.

In addition, until recently, various studies using shear thickening solutions have been attempted, and a bulletproof material having a shear thickening liquid and a method of manufacturing the same (Application No. 10-2010-0056722), a sword and a policy panel having a shear thickening liquid and a manufacturing method thereof (application) No. 10-2010-0064544).

However, the conventional techniques lack the optimization technology for hybrid with the STF material and the existing material, the buffer effect in the daily impact, but does not work in a large impact and the particles constituting the shear thickening liquid is mostly inorganic particles high content There is a problem in that the shear thickening liquid is heavy and not easy to light weight.

In other words, due to the high density of inorganic particles such as silica, it is impossible to commercialize the protective clothing because it is impossible to reduce the weight of the protective clothing.

The present invention is to solve the above problems, by producing a shear thickening solution using a hybrid mixture of low-density hollow silica beads and organic polymer particles, shearing thickening for protection using low-density silica excellent in wearing comfort and lightweight It is an object of the present invention to provide a method for preparing a liquid.

In order to achieve the above object, the present invention comprises the steps of synthesizing low-density hollow silica beads, excluding the calcination process, modifying the surface of the hollow silica beads, the surface-modified hollow silica beads and organic A method for preparing a protective shear concentrate for protection using low density silica, and a protective shear concentrate for protection by using the same, comprising preparing a mixture of polymer particles and dispersing the mixture in a solvent. We make good news a technical gist.

Moreover, it is preferable that the said hollow silica bead has a density of 1.7-1.8 g / cc.

In addition, the step of modifying the surface of the hollow silica beads, coating the surface of the hollow silica beads with a polymer material, the thickness is preferably 2 ~ 30nm.

In addition, the step of preparing a mixture of the hollow silica beads and the organic polymer particles, it is preferable that the organic silica particles 10 to 30 parts by weight based on 100 parts by weight of the hollow silica beads.

In addition, the step of dispersing the mixture in a solvent, the mixture is formed of 40 to 60 parts by weight of the mixture with respect to 100 parts by weight of the solvent, the viscosity is preferably at least 1000cps.

The present invention is prepared by applying a shear thickening solution using a hybrid mixture of low-density hollow silica beads and organic polymer particles, and applied to protective clothing, excellent anti-ballistic and anti-skid performance, excellent wearing comfort and lightweight protective clothing Has the effect of providing.

1-a block diagram for a method for preparing a shear thickener for protection according to the present invention.
Figure 2-Figure showing a photograph of a low density hollow silica beads made in accordance with one embodiment of the present invention.
Figure 3, Figure 4-Figure showing a photograph of the protective material produced according to an embodiment of the present invention.

The present invention relates to a shear thickening solution used in protective clothing such as body armor and a sword suit, by producing a shear thickening solution using a hybrid mixture of low-density hollow silica beads and organic polymer particles to achieve excellent fit and light weight It is to provide a protective clothing for a protective clothing.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram of a method for preparing a shear thickener for protection according to the present invention.

As shown, a method for preparing a shear thickener for protection using low density silica according to the present invention comprises the steps of synthesizing a low density hollow silica beads except for the calcination process, and modifying the surface of the hollow silica beads; Preparing a mixture of the surface modified hollow silica beads and organic polymer particles, and dispersing the mixture in a solvent.

  Protective shear concentrate using low density silica according to the present invention synthesizes low-density hollow silica beads except for the calcination process.

Conventional silica beads are prepared by a microemulsion method, a sol-gel method using tetraethyl orthosilicate (TEOS), spray drying or spray pyrolysis.

That is, the silica beads synthesized from the above process are prepared in the order of washing, drying, calcining and milling to provide hollow silica beads, among which the calcining process heat-decomposes the remaining volatile components after the reaction. In this case, the heating loss is achieved, and thus, when the process is removed, low-density hollow silica beads according to the present invention can be obtained.

As a result of measuring the density after the milling process by securing the synthesized hollow silica beads except for the calcination process, the natural silica was approximately 2.65 g / cc or 2.2138 g / cc even in the case of synthesized silica beads. cc was confirmed to have a very low density compared to the conventional silica or silica beads.

The particle size of the hollow silica beads is preferably 20 ~ 500nm, if smaller than this, the shear shear rate is increased too much, if larger than this, the starting point of shear thickening is delayed.

The hollow silica beads thus prepared are subjected to surface modification. This is to improve the dispersibility on a solvent or an organic solvent to be described later, the surface modification is performed by coating the surface of the hollow silica beads with a polymer material.

The polymeric material used for surface modification of the hollow silica beads is coated on the surface of the hollow silica beads and preferably has a thickness of 2 to 30 nm, which is a range for expressing an optimum shear thickening effect, in a solvent. To achieve uniform dispersion.

Surface modification by coating the surface of the hollow silica bead of the polymer material may be realized through a silane coupling agent treatment. For example, an epoxy group containing silane coupling agent, an acryl group containing silane coupling agent, an isocyanate group containing silane coupling agent, etc. can be used as said silane coupling agent.

The surface-modified hollow silica beads are mixed with organic polymer particles to prepare a mixture. The organic polymer particles may be synthesized by using suspension polymerization in which size and size distribution are controlled.

Shear thickening solution determines the shear thickening properties by the size of the hollow silica beads and organic polymer particles, particle size distribution, particle shape, and mutual attraction between particles, and provides antiballistic and anti-glare properties, and effective external impact energy. In consideration of the release, activity and light weight, such parameters as the size of the hollow silica beads and organic polymer particles are used.

PS, PMMA, PVC, PCL (polycaprolactone), PC, etc. are used as the organic polymer particles, 10 to 30 parts by weight of the organic polymer particles with respect to 100 parts by weight of the hollow silica beads, the existing silica beads Instead, low-density hollow silica beads with low density are used, and organic polymer particles of lower density are mixed and used to achieve lighter weight as well as ballistic and anti-glare performance.

Then, the mixture is dispersed in a solvent and adjusted to an appropriate concentration to complete the shear concentrate.

The mixture is used in an amount of 40 to 60 parts by weight based on 100 parts by weight of the solvent, and the viscosity is 1000 cps or more, so that the shear thickening phenomenon occurs smoothly.

In other words, if the content of the mixture falls, the shear thickening phenomenon is weak and the shock absorbing power is lowered. If this exceeds, the weight is increased by using more particles than necessary.

The solvent is used by mixing any one of ethylene glycol or polyethylene glycol and ethanol, ethyl acetate, toluene, ether, acetone, methyl ethyl ketone, and adjust the content of ethanol relative to ethylene glycol or polyethylene glycol for viscosity control Can be used.

The shear thickening solution thus prepared may be used as a protective material by fusing with Kevlar fabric, and provided by the method of coating or impregnation on Kevlar fabric.

The Kevlar fabric is laminated in 4 to 8 layers according to the anti-ballistic and anti-glare performance, and the shear thickening solution is coated with a thickness of about 10 to 20 μm on the Kevlar fabric.

Thinner than this reduces the deformation suppression effect of the Kevlar fabric during impact, and if exceeded, the fabric becomes stiff and the fabric is destroyed even with a small impact or a deterioration of fit.

Hereinafter will be described the experimental example and one embodiment for securing the manufacturing process according to the present invention.

First, as a basic study, a simple shear thickening process was carried out.Because the calcination process was excluded, the silica beads containing excess ethanol were ball milled for 24 hours and 6 hours at room temperature mixing for 150 hours. Although the dispersibility may be reduced, a simple method of preparing a shear thickener that can compare appearance and impregnation performance in a laboratory was obtained.

Through this preparation method, silica was obtained at 66.7 wt% or more based on residual shear concentrate after ethanol was dried at a high temperature, and mixing was found to be difficult at 70 wt% or more.

Shear thickening was expected to be found as a result of a simple test at 34wt% or more, but it was satisfied in the mixing dry state, but the polyethylene glycol used as the shear thickening medium and the layer separation phenomenon were observed when left at room temperature. It is determined that the hollow silica beads are suspended in polyethylene glycol due to the large difference in density between the polyethylene glycol and the hollow silica beads according to the present invention.

Meanwhile, the low density hollow silica beads according to the present invention were synthesized by the microemulsion method, and were prepared in the order of washing, drying and milling except for the calcination process to provide hollow silica beads.

Hollow silica beads according to the present invention except for the calcination process, thereby obtaining a hollow silica beads of low density, by securing the synthesized hollow silica beads excluding the calcination process and measuring the density after the milling process As a result, it was confirmed that the natural silica was approximately 2.65 g / cc, but the synthesized silica beads were 1.7138 g / cc, which was much lower than the conventional silica or silica beads at 2.2138 g / cc. Figure 2 shows a picture of a hollow silica bead prepared according to an embodiment of the present invention. Figure 2 (a) has undergone a calcination process, Figure 2 (b) excludes the calcination process.

This comparison is shown in Table 1 below.

Silica density Solution density
(Theoretical calculation) usage Body Armor Weight Loss g / cc g / cc kg % natural
2.65 1.935 1.39 - Synthetic Beads
(calcination) 2.214 1.703 1.23 0 Synthetic Beads
(Excluding calcination process) 1.787 1.476 1.06 4.86

STF: PEG200 (d 1.124g / cc), based on 53% silica volume fraction

STF 200cc / ㎡, 8 layer application standard,

Body armor 6.8kg, 0.45㎡

As shown in Table 1, if the STF 200cc / ㎡, Kevlar fabric 8 layer applied to 0.45㎡ kevlar body can be expected to reduce the weight of about 4.86% compared to the conventional synthetic silica beads.

Through the experimental conditions described above was carried out the process of fusing the shear thickener to Kevlar fabric.

Kevlar fabrics were commercially available with a thickness of 350㎛ 1000d, and the back coating was first applied to approximately 40㎛ using a urethane adhesive coating agent. Then, using a paper release paper as a primary paper, the shear thickening liquid according to the present invention was operated using a comma coater based on the 50 μm coating, and the process was designed to be laminated with Kevlar fabric after passing through a drying chamber.

The concentration of silica was reduced to 50.8% by volume in consideration of the penetration of some of the shear thickening solution.In addition, 20% of ethanol was added to polyethylene glycol because the viscosity of the coating agent had to exceed 1000 cps due to the comma characteristics (hollow silica beads: Polyetherylene glycol: ethanol = 2.06: 1: 0.2) to adjust the viscosity, it was dried sufficiently in a drying chamber.

As a result of the operation, the shear thickening solution was applied to the surface of the Kevlar fabric by about 13 μm, which is thought to be due to some penetration of STF into the Kevler fabric.

As a result of SEM confirmation, it was confirmed that the STF silica layer on the surface was sufficiently formed (FIG. 3), and it was confirmed that the penetrates and dispersed partly in the fabric. As a result of confirming the back side by SEM, the part where the urethane coating layer was not partially applied was confirmed (FIG. 4), but since the silica was not confirmed, the STF was not diffused to the back side.

Mass production experiments were conducted on the Kevlar fabric impregnation and a part of the shear thickening layer in a vertically sealed structure with double-sided release paper, but the shear thickening layer was found to be solidified under the above conditions.

This is judged to be due to the possibility of evaporation of polyethylene glycol due to the difference in vapor pressure in the drying chamber and the side due to the concentration decrease due to diffusion in the form of capillary into the base fabric layer of polyethylene glycol.

The experimental results to date are structurally possible to stack and impregnate STF by comma coater.However, to prevent STF solidification, the volume fraction of hollow silica beads in consideration of sufficient capillary diffusion of polyethylene glycol in the fabric is reduced. It is possible to find the optimal composition ratio that can show the shear thickening phenomenon while maintaining the liquid phase of the shear thickening liquid.

It is deemed necessary to establish conditions that can minimize evaporation due to the difference in vapor pressure of polyethylene glycol according to drying conditions, and design a laminated structure to minimize the concentration change of polyethylene glycol after lamination of shear concentrate. Can be.

Claims (16)

Synthesizing low density hollow silica beads having a density of 1.7 ~ 1.8g / cc excluding the calcination process;
Modifying the surface of the hollow silica beads;
Preparing a mixture of 10-30 parts by weight of the organic polymer particles having a lower density than the silica beads, based on 100 parts by weight of the surface-modified hollow silica beads; And
Dispersing 40 to 60 parts by weight of the mixture with respect to 100 parts by weight of the solvent to adjust the viscosity to 1000cps or more; Protective shear concentrate production method using a low density silica, characterized in that comprises a. delete The method of claim 1, wherein modifying the surface of the hollow silica beads,
Method for producing a shear thickening liquid for protection using low density silica, characterized in that the coating of the surface of the hollow silica beads with a polymer material. 4. The method of claim 3, wherein the coating of the polymer material on the surface of the hollow silica beads has a thickness of 2 to 30 nm. delete delete delete delete delete delete delete delete delete delete delete delete

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