Patent Application
20140199905
The present invention relates to a bulletproof fabric and a method for producing the same. More specifically, the present invention relates to a bulletproof fabric and a method for producing the same that exhibit improved anti-trauma property and minimize deterioration in bulletproofness even after use under harsh conditions for a long period of time.
A bulletproof garment is clothing that is developed to protect the body from fragments of shells or bullets. Accordingly, the most important requirement of bulletproof garments is bulletproofness. However, since high-strength fibers constituting the bulletproof garment are vulnerable to water, a serious problem such as deterioration in bulletproofness of bulletproof garments under harsh environments or after use for a long period of time occurs.
In order to solve this problem, the applicant suggested a water repellent treatment method using a bulletproof fabric (Korean Patent Laid-open No. 10-2010-0023491). However, a problem in which water repellency imparted to the bulletproof fabric using water repellent treatment cannot be maintained for a long period of time still remains. That is, the water-repellent agent component (for example, a fluorocarbon compound) that is adhered to the bulletproof fabric through water repellent treatment is disadvantageously readily removed from the bulletproof fabric due to exterior environments and/or passage of time. As a result, a conventional bulletproof garment has a serious problem in that bulletproofness thereof is significantly deteriorated under harsh environments or after use for a long period of time.
Meanwhile, a user that wears a bulletproof garment should be able move without inconvenience. For this reason, wear feeling, in addition to bulletproofness, is an important requirement of bulletproof garments. When the bulletproof garment is excessively heavy or inflexible, it is not considered to be a good bulletproof garment due to deteriorated wear feeling although it exhibits superior bulletproofness. In consideration of wear feeling, the bulletproof garment should be produced with a soft bulletproof fabric having a stiffness (flexibility) of 10 N to 70 N. However, a general soft bulletproof fabric has a limitation of unsatisfactory anti-trauma property.
The anti-trauma property is an important bulletproof property of bulletproof garment. A bulletproof fabric is locally deformed, when physical shock is applied thereto by a bullet and deformation of the collision surface expands to the rear surface of the bulletproof fabric and backface deformation exceeding an acceptable safety distance may occur. Serious backface deformation of the bulletproof fabric may cause fatal damage to users.
Therefore, the present invention is directed to a bulletproof fabric and a method for producing the same capable of preventing problems based on these limitations and drawbacks of the related art.
It is one object of the present invention to provide a bulletproof fabric that minimizes backface deformation caused by physical shock as well as deterioration in bulletproofness under harsh environments after use for a long period of time.
It is one another of the present invention to provide a method for producing a bulletproof fabric that minimizes backface deformation caused by physical shock as well as deterioration in bulletproofness under harsh environments and after use for a long period of time.
Other features and advantages of the present invention will be described below and will be partially apparent from the description. Otherwise, other features and advantages of the present invention will be understood from implementation of the present invention. The objects and other advantages of the present invention will be realized and accomplished by the configuration specified in the annexed drawings as well as the detailed description and claims.
In accordance with one aspect of the present invention, provided is a bulletproof fabric comprising: a fabric comprising at least one high-strength fiber selected from the group consisting of a high molecular weight polyethylene fiber, an aramid fiber, and a polybenzoxazole fiber; and a water repellent layer disposed on the high-strength fiber, wherein the water repellent layer is formed by treating the fabric with a water-repellent agent comprising fluorocarbon and a hardness-enhancing resin, and the hardness-enhancing resin is a polyvinyl acetate resin, a polyester resin, a polyacrylate resin, a melamine resin, or a mixture of two or more thereof.
In accordance with another aspect of the present invention, provided is a method for producing a bulletproof fabric comprising: preparing a fabric using at least one high-strength fiber selected from the group consisting of a high molecular weight polyethylene fiber, an aramid fiber, and a polybenzoxazole fiber; preparing a water-repellent agent comprising fluorocarbon and a hardness-enhancing resin; applying the water-repellent agent to the fabric; and heat-treating the water-repellent agent-applied fabric, wherein the hardness-enhancing resin is a polyvinyl acetate resin, a polyester resin, a polyacrylate resin, a melamine resin, or a mixture of two or more thereof.
The general description provided above and the detailed description provided below are provided only for illustration of the present invention and are to be construed as providing a more detailed description of inventions defined in claims.
According to the present invention, a bulletproof garment produced using the bulletproof fabric of the present invention minimizes backface deformation caused by shock or impact without affecting wear feeling, thereby preventing or minimizing damage to the body from shell fragments or bullets.
Also, the bulletproof garment produced using the bulletproof fabric can maintain superior bulletproofness even after use under harsh environments for a long period of time.
Other effects of the present invention will be described in detail below together with technical configurations associated therewith.
Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention. Accordingly, the present invention includes all alternations and modifications that fall within the scope of inventions described in claims and equivalents thereto.
Hereinafter, a bulletproof fabric and a method for producing the same according to one embodiment of the present invention will be described in detail with reference to the annexed drawings.
The bulletproof fabric of the present invention comprises a fabric made of at least one high-strength fiber of a high molecular weight polyethylene fiber, an aramid fiber and a polybenzoxazole fiber.
In one embodiment of the present invention, a fabric is woven using one of a high molecular weight polyethylene fiber, an aramid fiber and a polybenzoxazole fiber as a warp and a weft. Selectively, different types of high-strength fibers may be used as warps and wefts, respectively. Also, warps and wefts of the fabric may comprise two or more different types of high-strength fibers.
Optionally, the fabric of the present invention may be a unidirectional fabric comprising a plurality of plies. Each ply comprises high-strength fibers that are arranged substantially in parallel and high-strength fibers of adjacent plies cross each other.
Optionally, the fabric of the present invention may be a felt in which monofibers are irregularly arranged.
Hereinafter, a method for weaving a fabric using a wholly aromatic polyamide fiber that is one type of an aramid fiber as a warp and a weft will be described in detail.
First, for production of a wholly aromatic polyamide fiber, aromatic diamine and aromatic diacid chloride are polymerized in a polymerization solvent to prepare an aromatic polyamide polymer. The aromatic polyamide polymer is dissolved in a concentrated solvent to prepare a spinning dope. The spinning dope passes through a plurality of holes of a spinneret and is then coagulated to prepare multifilaments.
Multifilaments having a predetermined fineness may comprise more monofilaments, as fineness of monofilaments decreases. The multi-filaments according to one embodiment of the present invention comprise thin monofilaments having a fineness of 1.6 denier or less and thus comprise a relatively large number of monofilaments. Accordingly, a fabric woven from the multi-filaments can exhibit improved shock absorbing properties.
Meanwhile, it is difficult to weave a fabric using multifilaments having a fineness lower than 0.7 denier. Accordingly, monofilaments constituting the multifilament preferably have a fineness of 0.7 or more in terms of easy weaving.
The wholly aromatic polyamide multifilaments according to one embodiment of the present invention comprise 400 to 1,600 monofilaments having a fineness of 0.7 to 1.6 denier. The wholly aromatic polyamide multifilaments have a tensile strength of 22 g/d or more in terms of bulletproofness of bulletproof fabrics. The present invention is not particularly limited as to the number and fineness of monofilaments and tensile strength of multifilaments.
Weaving of the fabric may be carried out by plain weaving or basket weaving. A warp density and a weft density may be 5 to 15 pcs/cm and the obtained fabric may have a tensile strength of 5,000 to 10,000 N/5 cm. The present invention is not particularly limited to warp density, weft density and tensile strength of fabrics.
After the fabric is prepared, a scouring process to remove oils or foreign matter adhered to a high-strength fiber may be performed.
Generally, a spinning oil applied immediately before the high-strength fiber is wound on a core may be present on the surface of the high-strength fiber. When a fabric is treated with a water-repellent in a state in which oils are adhered to the surface of the fibers, a bonding force between the water-repellent agent and the fabric cannot be obtained. As a result, as time goes by, rapid deterioration in water repellency and thus deterioration in bulletproofness may occur. Accordingly, the scouring process to remove oils or foreign matter adhered to the high-strength fiber is preferably performed before water-repellent treatment.
The scouring process may be carried out at 40 to 100° C. using a scouring agent comprising a surfactant such as NaOH and/or Na2CO3. After the fabric is treated with the scouring agent, it is washed with water and is then dried.
Subsequently, the fabric is treated with a water-repellent agent comprising fluorocarbon and a hardness-enhancing resin of the present invention to form a water repellent layer on the high-strength fiber.
The fluorocarbon compound functions to impart water repellency to the fabric. A hydroxylated perfluoroalkylethyl acrylate copolymer may be used as the fluorocarbon compound.
The hardness-enhancing resin enhances hardness of the fabric and thereby inhibits backface deformation of bulletproof fabric caused by shock. As the hardness-enhancing resin, a polyvinyl acetate resin, a polyester resin, a polyacrylate resin, a melamine resin or a mixture of two or more thereof may be used.
Optionally, the water-repellent agent of the present invention may further comprise a cross-linking agent. The cross-linking agent may be an isocyanate compound such as toluene diisocyanate or methylene diphenyl diisocyanate. The cross-linking agent enhances bonding between fluorocarbon that imparts water repellency to the fabric and the fabric and thereby enables the bulletproof fabric to continuously maintain superior bulletproofness even after use under harsh environments for a long period of time.
Optionally, the water-repellent agent of the present invention may further comprise an antifoaming agent to remove foams, such as dipropylene glycol.
Optionally, the water-repellent agent of the present invention may further comprise a pH adjuster such as maleic acid.
Optionally, the water-repellent agent of the present invention may further comprise an emulsion stabilizer, such as malic acid.
The water-repellent agent according to one embodiment of the present invention comprises 0.5 to 10% by weight of fluorocarbon, 0.5 to 10% by weight of a hardness-enhancing resin, 0.5 to 5% by weight of a cross-linking agent, 0.02 to 2% by weight of an antifoaming agent, 0.02 to 2% by weight of a pH adjuster, 0.1 to 2% by weight of an emulsion stabilizer, and 69 to 98.36% by weight of water.
When the content of fluorocarbon compound is lower than 0.5% by weight, desired water repellency cannot be obtained and when the content exceeds 10% by weight, an increase in water repellency is not great, but flexibility of bulletproof fabric may be deteriorated.
When the content of the hardness-enhancing resin is lower than 0.5% by weight, an improvement in anti-trauma property of the bulletproof fabric is almost not exhibited and when the content exceeds 10% by weight, the flexibility of bulletproof fabric is deteriorated and a bulletproof garment made of the bulletproof fabric also exhibits great deterioration in wear feeling and water repellency.
When the content of cross-linking agent is lower than 0.5% by weight, water repellency cannot be maintained to a desired level, and when the content exceeds 5% by weight, only production costs disadvantageously increase without additional effects.
When the content of the antifoaming agent is lower than 0.02% by weight, foam removal function may be deteriorated and when the content exceeds 2% by weight, ratios of other components to maintain properties such as water repellency, flexibility, anti-trauma property, and water repellency are deteriorated and these properties thus cannot be improved.
When the content of pH adjuster is lower than 0.02% by weight, pH of the water-repellent agent cannot be controlled within a desired range, and when the content exceeds 2% by weight, ratios of other components to maintain properties such as water repellency, flexibility, anti-trauma, and water repellency are deteriorated and these properties thus cannot be improved.
The emulsion stabilizer cannot exert a stabilization function when used at an amount of 0.1% by weight and may cause deterioration in physical properties of the fabric, when used at an amount exceeding 2% by weight.
Treatment of the fabric with a water-repellent agent includes applying the water-repellent agent to the fabric and heat-treating the water-repellent agent-applied fabric.
Application of the water-repellent agent to the fabric may be carried out by a method such as padding, coating, immersion, spraying, brushing or film-coating. According to one embodiment of the present invention, the water-repellent agent is impregnated into the fabric by immersing the fabric in the sufficiently stirred water-repellent agent.
Heat-treatment of the water-repellent agent-applied fabric may be carried out at 120 to 200° C. for 15 to 150 seconds. Through the heat-treatment, water is removed, the water-repellent agent is cured and a water repellent layer is finally formed. When the heat-treatment temperature is lower than 120° C. or the heat-treatment time is shorter than 15 seconds, the effect of water repellent treatment may be deteriorated and, when heat-treatment temperature exceeds 200° C. or heat-treatment time exceeds 150 seconds, the fabric may be damaged.
The bulletproof fabric produced by the method of the present invention has a stiffness (flexibility) of 10 to 70 N. The stiffness is an index of flexibility of a bulletproof fabric, which is measured through a circular bending procedure in accordance with ASTM D4032. When stiffness of bulletproof fabric is lower than 10 N, the strength of bulletproof fabric is excessively low and thus bulletproofness, in particular, the anti-trauma property is not good. On the other hand, when the stiffness of the fabric exceeds 70 N, flexibility of bulletproof fabric is lacking and a bulletproof garment made of the bulletproof fabric does not have a wear feeling.
Also, in the bulletproof fabric of the present invention, backface deformation measured using an average speed of 44 Mag. bullet measured in accordance with the regulation of NIJ Level IIIA is 44 mm or less. That is, the bulletproof fabric of the present invention exhibits improved anti-trauma although it has superior flexibility.
The bulletproof fabric produced by treating the fabric with the water-repellent agent comprising a polyvinyl acetate resin as a hardness-enhancing resin satisfies the stiffness requirement of 10 to 70 N and exhibits superior anti-trauma of 40 mm or less backface deformation. That is, when the water-repellent agent comprising a polyvinyl acetate resin as a hardness-enhancing resin is used, a bulletproof fabric can be obtained which has flexibility of such degree as generally required for good wear feeling of the bulletproof garment, and improved anti-trauma as well.
The bulletproof fabric of the present invention has a class IV to V initial water repellency (initial resistance to surface wetting) and water repellency of the bulletproof fabric after friction 500 times is class IV or higher. The water repellency means water repellency of a bulletproof fabric, which is measured by a spray method based on ISO 4920:1981. The friction to the bulletproof fabric is carried out using a Shiefer-type wear tester (SAT-250).
The bulletproof fabric of the present invention has class IV to V initial water repellency (initial resistance to surface wetting) and maintains high water repellency of class IV or more, even after friction of 500 times. This means that the bulletproof fabric of the present invention maintains superior water repellency even after use for a long period of time and, as a result, deterioration in bulletproofness caused by moisture absorption can be minimized.
Also, the bulletproof fabric of the present invention has a class IV to V rain proofness (water repellency under stress, Bundesmann Test, 10 min.). The rain proofness of the bulletproof fabric means water repellency of bulletproof fabric under harsh environments, that is, an index indicating a maintenance level of bulletproofness, which is measured in accordance with an ISO 9685:1992 method.
A bulletproof garment may be produced using a laminate including 10 to 50 pieces of the bulletproof fabric of the present invention thus produced. The bulletproof garment exhibits superior properties such as water repellency, flexibility, and anti-trauma, and deterioration in bulletproofness can be minimized even after use for a long period of time under harsh environments.
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
A fabric was woven as a plain weave using wholly aromatic polyamide multi-filaments comprising wholly aromatic polyamide monofilaments having a fineness of 1.0 as warps and wefts. The warp density and the weft density were 10 pcs/cm. Subsequently, the fabric was treated at about 60° C. with a scouring agent comprising Naz CO3, washed with water and dried.
Subsequently, the scoured fabric was immersed in a water-repellent agent to impregnate the water-repellent agent in the fabric. The water-repellent agent comprises 3% by weight of a hydroxylated perfluoroalkylethyl acrylate copolymer, 3% by weight of polyethylene terephthalate, 3% by weight of toluene diisocyanate, 0.3% by weight of diprophylene glycol, 0.3% by weight of maleic acid, 0.3% by weight of maleic acid, and 90.1% by weight of water.
The water-repellent agent-impregnated fabric was heat-treated at a temperature of about 160° C. for 60 seconds to complete a bulletproof fabric.
A bulletproof fabric was prepared in the same manner as in Example 1, except that a water-repellent agent comprising the same amount of a polyacrylate resin, instead of polyethylene terephthalate was used.
A bulletproof fabric was prepared in the same manner as in Example 1, except that a water-repellent agent comprising the same amount of a melamine resin, instead of polyethylene terephthalate was used.
A bulletproof fabric was prepared in the same manner as in Example 1, except that a water-repellent agent comprising the same amount of a polyvinyl acetate resin, instead of polyethylene terephthalate was used.
A bulletproof fabric was prepared in the same manner as in Example 1, except that toluene diisocyanate was not contained in a water-repellent agent and a content of water of the water-repellent agent was 93.1% by weight.
A bulletproof fabric was prepared in the same manner as in Example 1, except that polyethylene terephthalate was not contained in a water-repellent agent and a content of water of the water-repellent agent was 93.1% by weight.
A bulletproof fabric was prepared in the same manner as in Example 1, except that polyethylene terephthalate and toluene diisocyanate were not contained in a water-repellent agent and a content of water of the water-repellent agent was 96.1% by weight.
The stiffness, backface deformation, initial water repellency, water repellency after friction and rain proofness of bulletproof fabrics prepared in Examples and Comparative Examples were measured in accordance with the following methods.
Measurement of Stiffness
A bulletproof fabric was cut to prepare a sample with a size of 100 mm×200 mm and stiffness of the sample was measured using a circular bending procedure in accordance with ASTM D4032. Specifically, a hole having a diameter of 38.1 mm was made in a base having a size of 102 mm×102 mm×6 mm, a sample that had been folded in half was placed thereon, and a force in which a bar pushes the sample through the hole and goes down was measured, when the sample was pressed with the bar. The results thus obtained are shown in Table 1 below.
Measurement of Backface Deformation
Backface deformation (mm) of bulletproof fabric was measured using a 44 Mag. bullet in accordance with the regulation of NIJ Level IIIA. The results thus obtained are shown in Table 1 below.
Measurement of Initial Water Repellency
A bulletproof fabric was cut to prepare a sample having a size of 250 mm×250 mm, and initial water repellency of the sample was measured using a spray method based on ISO 4920:1981. The results thus obtained are shown in Table 1 below.
Measurement of Water Repellency after Friction
A bulletproof fabric was cut to prepare a sample having a size of 250 mm×250 mm and friction was applied to the sample 500 times using a Shiefer-type wear abrasion tester (SAT-250). Subsequently, water repellency of the sample was measured using a spray method based on ISO 4920:1981. The results thus obtained are shown in Table 1 below.
Measurement of Rain Proofness
A bulletproof fabric was cut to prepare a sample having a size of 250 mm×250 mm and rain proofness of the sample was measured using a Bundesmann test (10 min., ISO9685:1992) method. The results thus obtained are shown in Table 1 below.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0086916 | Aug 2011 | KR | national |
| 10-2012-0051216 | May 2012 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR2012/006938 | 8/30/2012 | WO | 00 | 1/17/2014 |
