Leg guard plate and preparation method thereof

Abstract

The invention belongs to the technical field of protective materials, and particularly relates to a leg guard plate and a preparation method thereof. The leg guard plate is of a curved surface structure, the whole front face is smooth, and the face attached to the skin is provided with a ventilation channel; comprising an elastic anti-slip structure layer, a fiber base material layer, an elastic impermeable layer, an energy absorption buffer layer and a plastic layer which are sequentially stacked from inside to outside. The leg guard plate is of a multi-layer composite structure, the elastic anti-slip structure layer has good anti-slip performance, and the leg guard plate is not prone to displacement in the using process and is well attached to the skin. The energy absorption buffer layer is made of a shear thickening composite material (NNF), so that impact force generated during impact can be effectively buffered and absorbed, and better protection is provided for legs. Meanwhile, the leg guard plate is provided with an anti-slip structure and a ventilation channel, so that heat and water vapor can be quickly taken away, and good air permeability is achieved. The leg guard plate is simple in structure, integrally formed, free of being sewn with fabric, capable of conforming to ergonomics, excellent in attaching performance and high in wearing comfort degree.

Description

Technical Field

[0001] The invention belongs to the technical field of protective materials, and in particular relates to a leg guard and a preparation method thereof. Background Art

[0002] Traditional shin guards generally do not have ergonomic designs, and are mostly made using stitching technology, with hard edges left around the edges for stitching. Currently, there are also some ergonomically designed protrusions on the front of the shin guards, but the protrusions on the front are often not conducive to accurate ball control when kicking, and are prone to cracking of the product due to stress concentration; the hard edges left around the edges during compounding or stitching result in poor product fit, and the product is not flexible and difficult to bend. In other words, the current shin guards do not conform to ergonomic designs as a whole, because there is no anti-slip structure on the inner surface that fits the human body, and they are prone to deviation, displacement, or even loss during strenuous exercise, and there are great limitations on wearing comfort and safety; in addition, the energy absorption and buffering effect is not ideal, and it is difficult to efficiently buffer external impact forces, resulting in poor protection. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a leg guard and a preparation method thereof. The leg guard of the present invention is an integrally formed composite layered structure, including a fiber substrate layer and an energy absorption buffer layer, does not need to be sewn, has good skin adhesion, is not easy to shift, and is convenient to wear and use; and has a good energy absorption effect, can effectively reduce the impact force generated when hit, and provide better protection for the legs.

[0004] The present invention provides a leg guard having a curved surface structure, wherein the outer surface is smooth as a whole and an air permeable channel is arranged on the inner surface;

[0005] The leg guard comprises an elastic anti-slip structure layer, a fiber base material layer, an elastic anti-seepage layer, an energy-absorbing buffer layer and a plastic layer which are sequentially stacked from the inside to the outside;

[0006] The energy absorbing buffer layer comprises shear thickening polyurethane, and the raw materials for preparing the shear thickening polyurethane comprise a premix and a curing agent;

[0007] The premix comprises the following components in parts by weight: 30-80 parts of polyether diol, 20-70 parts of polyether polyol, 1-20 parts of chain extender, 0.5-3 parts of cross-linking agent, 5-50 parts of filler, 0.5-5.0 parts of coupling agent, 0.05-15 parts of foaming agent, 0.1-5.0 parts of emulsifier, and 0.05-5.0 parts of catalyst; the number of hydroxyl groups of the polyether polyol is more than 3, and the hydroxyl value of the polyether polyol is 22-56 mg KOH / g;

[0008] The curing agent includes but is not limited to isocyanate or modified isocyanate;

[0009] The molar ratio of the hydroxyl group in the premix to the isocyanate group in the curing agent is 1:1 to 1.1.

[0010] Preferably, the thickness of the energy absorbing buffer layer is 4 to 10 mm.

[0011] Preferably, the elastic anti-slip structural layer is made of an elastic material, and the elastic material includes polyvinyl chloride, thermoplastic polyurethane, TPR, TPS, TPO or silicone.

[0012] Preferably, the elastic anti-slip structural layer has a thickness of 0.3-1 mm, and the elastic anti-slip structural layer has a geometric or non-geometric structure in the form of a honeycomb, a wave, a stripe or a dot.

[0013] Preferably, the material of the fiber substrate layer includes lycra, spandex or polyester.

[0014] Preferably, the fiber substrate layer has a thickness of 0.06 to 0.3 mm.

[0015] Preferably, the elastic anti-seepage layer comprises a TPU film.

[0016] Preferably, the elastic anti-seepage layer has a thickness of 0.01 to 0.1 mm.

[0017] The present invention also provides a method for preparing the leg guard described in the above technical solution, comprising the following steps:

[0018] The elastic anti-slip material is attached to the surface of one side of the fiber substrate layer, and the surface of the other side of the fiber substrate layer is thermally laminated with the elastic anti-seepage membrane to obtain a pre-laminated layer;

[0019] The raw materials for preparing the energy-absorbing buffer layer are poured between the pre-composite layer and the plastic layer, and foaming and cross-linking are performed for integrated molding to obtain the leg guard.

[0020] Preferably, the temperature of the foaming, cross-linking and integrated molding is 35 to 80° C., and the time is 2 to 10 minutes.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a shin guard, which is a curved structure, the outer surface is smooth as a whole, and the inner surface is provided with a breathable channel; the shin guard comprises an elastic anti-slip structure layer, a fiber base material layer, an elastic anti-seepage layer, an energy-absorbing buffer layer and a plastic layer stacked in sequence from the inside to the outside. The shin guard of the present invention is a multi-layer composite structure, provided with an elastic anti-slip structure layer, has good anti-slip performance, good skin fit during use, not easy to shift, and is provided with an energy-absorbing buffer layer, using a shear thickening composite material (NNF), has good energy-absorbing buffer performance, can effectively buffer the impact force generated when hit, and provide better protection for the legs. At the same time, the shin guard of the present invention is provided with a breathable channel, which is conducive to gas flow, can quickly take away heat and water vapor, and has good air permeability. Moreover, the shin guard of the present invention has a simple structure, and the shin guard product can be directly placed in a football sock when in use, without the need to sew with the fabric, which is convenient to wear and use. The inner surface of the shin guard of the present invention is ergonomic, has excellent fit performance, and is highly comfortable to wear.

[0023] The energy absorption buffer layer of the present invention is a shear thickening material, polyether polyol provides a network support for the hard segment, and polyether diol provides buffering energy absorption. When the impact force is large, the hard segment network contained in the polyether polyol supports each other and can quickly assemble, giving high impact resistance and high energy absorption characteristics, achieving the effects of damping, energy absorption, and vibration reduction; when the impact force is released, the soft segment provided by the polyether diol can prevent the instantaneous rebound of the hard segment network. The shear thickening material remains soft and has a suitable solid elastic state under normal conditions. When it is subjected to rapid and severe impact or extrusion, it can quickly increase strain through local density increase, showing an obvious shear thickening phenomenon, that is, when the material is impacted by an external force, it behaves as a hard solid, and as the external force increases, the strength of the material increases; when the external force disappears, the material will return to its original relaxed soft elastic state. The leg guard has energy absorption and buffering properties and can absorb strong impact forces.

[0024] The present invention also provides a method for preparing the shin guards described in the above technical solution. The shin guards with shear thickening properties are prepared by multi-layer composite and integrated molding technology. The shin guards will not wear the skin due to cracking of the product and are comfortable to wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 Schematic diagram of the layered structure of the shin guard of the embodiment;

[0027] Figure 2 It is a schematic diagram of a shin guard product according to an embodiment;

[0028] Figure 3 A schematic diagram of the ergonomic design of the shin guard product;

[0029] Figure 4 Schematic diagram of the football shin guard product obtained in Examples 1 to 3;

[0030] Figure 5 A picture of a shin guard product sold on the market;

[0031] Figure 6 This is the flexibility result diagram of the two NNF layers in Test Example 2. DETAILED DESCRIPTION

[0032] The present invention provides a leg guard having a curved surface structure, wherein the outer surface is smooth as a whole and an air permeable channel is arranged on the inner surface;

[0033] The leg guard comprises an elastic anti-slip structure layer, a fiber base material layer, an elastic anti-seepage layer, an energy-absorbing buffer layer and a plastic layer which are sequentially stacked from the inside to the outside;

[0034] The energy absorbing buffer layer comprises shear thickening polyurethane, and the raw materials for preparing the shear thickening polyurethane comprise a premix and a curing agent;

[0035] The premix comprises the following components in parts by weight: 30-80 parts of polyether diol, 20-70 parts of polyether polyol, 1-20 parts of chain extender, 0.5-3 parts of cross-linking agent, 5-50 parts of filler, 0.5-5.0 parts of coupling agent, 0.05-15 parts of foaming agent, 0.1-5.0 parts of emulsifier, and 0.05-5.0 parts of catalyst; the number of hydroxyl groups of the polyether polyol is more than 3, and the hydroxyl value of the polyether polyol is 22-56 mg KOH / g;

[0036] The curing agent includes isocyanate or modified isocyanate;

[0037] The molar ratio of the hydroxyl group in the premix to the isocyanate group in the curing agent is 1:1 to 1.1.

[0038] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0039] In the present invention, the air permeable channel is preferably arranged longitudinally.

[0040] In the present invention, the material of the elastic anti-slip structural layer is preferably an elastic material, and the elastic material preferably includes polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), TPR, TPS, TPO or silicone. The elastic anti-slip structural layer is preferably obtained by drop molding, screen printing or printing the elastic material onto the outer surface of the fiber substrate, and the elastic anti-slip layer structure is preferably a honeycomb, wavy, striped or dotted geometric or non-geometric structure. When using the leg guard, the elastic anti-slip structural layer fits the leg.

[0041] In the present invention, the thickness of the elastic anti-slip structural layer is preferably 0.3-1 mm, specifically 0.5 mm or 0.7 mm.

[0042] In the present invention, the material of the fiber substrate layer preferably includes Lycra, Spandex (Spandex polyurethane fiber) or Dacron (polyester fiber).

[0043] In the present invention, the thickness of the fiber substrate layer is preferably 0.06-0.3 mm, specifically 0.1 mm, 0.14 mm or 0.2 mm.

[0044] In the present invention, the elastic anti-seepage layer preferably includes a TPU film, and the TPU film is preferably 82A. The TPU film is preferably combined with the inner surface of the fiber substrate layer by thermal bonding.

[0045] In the present invention, the thickness of the elastic anti-seepage layer is preferably 0.01-0.1 mm, specifically 0.03 mm or 0.05 mm.

[0046] In the present invention, the polyether diol preferably includes polyoxypropylene diol and / or polyoxypropylene-ethylene oxide polyether diol. The polyether diol can provide a soft segment chain structure, provide buffering energy absorption, and prevent the instantaneous rebound of the hard segment network.

[0047] In the present invention, the polyether polyol preferably includes one or more of polyoxypropylene polyol, polyoxyethylene polyol and polyoxypropylene-ethylene oxide copolymer polyol. The polyether polyol is preferably a polyether triol. The polyether polyol can provide a network support for the hard segment. When subjected to impact force, the hard segment networks support each other and can quickly assemble, giving the material high impact resistance and high energy absorption characteristics, thereby achieving the effects of damping, energy absorption and vibration reduction.

[0048] In the present invention, the chain extender preferably includes a first chain extender and / or a compound chain extender, and the first chain extender preferably includes one or more of 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 4,4'-bis-sec-butylaminodiphenylmethane, methyl propanediol, 1,6-hexanediol, 1,4-bis(2-hydroxyethoxy)benzene, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol and hydroquinone bis(2-hydroxyethyl) ether; the compound chain extender is preferably prepared by chain extension reaction of raw materials including the first chain extender and a chain extension curing agent.

[0049] In the present invention, the cross-linking agent preferably includes an alcoholamine cross-linking agent and / or an alcohol cross-linking agent, the alcoholamine cross-linking agent preferably includes one or more of ethanolamine, diethanolamine and triethanolamine, and the alcohol cross-linking agent preferably includes ethylene glycol and glycerol. The cross-linking agent can generate chemical bonds between linear molecules, so that the linear molecules are connected to each other to form a network structure, thereby improving the strength and elasticity of the material.

[0050] In the present invention, the filler preferably includes one or more of white carbon black, wollastonite powder, kaolin, silica powder, carbon black and glass fiber. The filler can improve the impact resistance of the material.

[0051] In the present invention, the coupling agent preferably includes an amino-containing silane coupling agent, which can ensure that the filler does not fall off or separate.

[0052] In the present invention, the foaming agent is preferably a physical foaming agent, and the physical foaming agent preferably includes one or more of H2O, dichloromethane, 1,1,1,3,3-pentafluorobutane and 1,1-dichloro-1-fluoroethane. The H2O is preferably deionized water. The foaming agent plays a foaming role to adjust the molding density of the product.

[0053] In the present invention, the emulsifier preferably includes a polysiloxane-oxyalkylene block copolymer.

[0054] In the present invention, the catalyst preferably includes one or more of dimethylethanolamine, triethylenediamine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N′,N′-tetramethylalkylenediamine, N,N-dimethylbenzylamine and an organic bismuth catalyst, and the catalyst can adjust the start time, demolding time and post-ripening time of the polymerization reaction.

[0055] In the present invention, the curing agent preferably includes diphenylmethane diisocyanate and / or 1,5-naphthalene diisocyanate.

[0056] In the present invention, the molar ratio of the hydroxyl group in the premix to the isocyanate group in the curing agent is preferably 1:1.01 to 1.05, and specifically may be 1:1.01.

[0057] The energy-absorbing buffer layer of the present invention is a shear-thickening material, which remains soft and has a suitable solid elastic state under normal conditions. When subjected to rapid and severe impact or extrusion, it can quickly increase strain through local density increase, showing an obvious shear-thickening phenomenon, that is, when the material is impacted by an external force, it behaves as a hard solid, and as the external force increases, the strength of the material increases; when the external force disappears, the material will return to its original relaxed soft elastic state. The leg guard of the present invention has energy-absorbing buffering performance and can absorb strong impact forces.

[0058] In the present invention, the raw material for preparing the shear thickening polyurethane is preferably NNF-SA produced by Huangshan Jiushi Technology Development Co., Ltd.

[0059] In the present invention, the thickness of the energy absorbing buffer layer is preferably 4 to 10 mm, more preferably 5 to 7 mm, and specifically may be 5.37 mm or 6.37 mm.

[0060] In the present invention, the material of the plastic layer preferably includes one or more of thermoplastic polyurethane (TPU), polypropylene (PP), polyethylene (PE), nylon (PA), polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene (ABS) and carbon fiber board.

[0061] In the present invention, the thickness of the plastic layer is preferably 0.8-3 mm, specifically 2 mm.

[0062] Take the elastic anti-slip structure layer obtained by drop molding as an example. Figure 1 It is a schematic diagram of the layered structure of the leg guard of the present invention, including an elastic anti-slip structure layer (plastic drop layer), a fiber base material layer (fabric layer), an elastic anti-seepage layer, an energy absorbing buffer layer (NNF) and a plastic layer. Figure 2 This is a schematic diagram of a shin guard, which has a curved design as a whole, a smooth front, and a honeycomb anti-slip structure and breathable channels on the skin-fitting layer. Figure 3 This is a schematic diagram of the ergonomic design of a shin guard product, where the wide head is the upper part, the narrow head is the lower part, and the thickness and curve are ergonomically designed.

[0063] The present invention also provides a method for preparing the leg guard described in the above technical solution, comprising the following steps:

[0064] The elastic anti-slip material is attached to the surface of one side of the fiber substrate layer, and the surface of the other side of the fiber substrate layer is thermally laminated with the elastic anti-seepage membrane to obtain a pre-laminated layer;

[0065] The raw materials for preparing the energy-absorbing buffer layer are poured between the pre-composite layer and the plastic layer, and foaming and cross-linking are performed for integrated molding to obtain the leg guard.

[0066] In the present invention, the elastic anti-slip material is attached to the surface of one side of the fiber substrate layer, and the surface of the other side of the fiber substrate layer is thermally composited with the elastic anti-seepage membrane to obtain a pre-composite layer.

[0067] In the present invention, the method of attaching the elastic anti-slip material preferably includes drop molding, screen printing or printing, and the elastic anti-slip material is preferably attached to the outer surface of the fiber substrate.

[0068] In the present invention, the temperature of the thermal bonding is preferably 160-180° C., and the elastic barrier membrane is preferably thermally bonded to the inner surface of the fiber substrate.

[0069] In the present invention, the thermal compounding preferably further includes cutting, and the cutting is preferably performed according to the size requirements of the leg guard molding mold.

[0070] After the pre-composite layer is obtained, the present invention pours the raw materials for preparing the energy-absorbing buffer layer between the pre-composite layer and the plastic layer, performs foaming and cross-linking integrated molding, and obtains the leg guard.

[0071] In the present invention, the mold for foaming and cross-linking integrated molding has a protrusion, and the protrusion is preferably a longitudinal protrusion.

[0072] In the present invention, the method preferably further comprises: mixing the premix and the curing agent at a high speed before pouring, wherein the rotation speed of the high speed mixing is preferably 3000 to 8000 rpm, more preferably 3500 to 4000 rpm, and the time is preferably 1 to 10 s.

[0073] In the present invention, the temperature of the foaming and cross-linking integrated molding is preferably 35-80°C, more preferably 50-70°C, specifically 55°C, and the time is preferably 2-10 min, more preferably 7-9 min, specifically 7 min, 8 min or 9 min.

[0074] In the present invention, the raw materials for preparing the pouring energy absorbing layer are preferably prepared in a mold, the mold has an exhaust channel and a quick locking function, and the quick locking function can be achieved by installing a quick locking clamp; the exhaust channel is preferably located at the uppermost end (highest point) of the mold cavity, and the diameter of the exhaust channel is preferably 0.3 to 3 mm, more preferably 1 mm. The mold preferably further comprises: uniformly spraying a release agent on the surface of the mold cavity before use.

[0075] The present invention preferably places the pre-composite layer and the plastic layer in the upper cavity and the lower cavity of the mold respectively, injects the raw material of the energy-absorbing buffer layer in the middle, and closes and locks the mold. The raw material of the energy-absorbing buffer layer undergoes polymerization, cross-linking, and solidification in the mold cavity, and is compounded with the pre-composite layer and the plastic layer at the same time. When the foaming pressure in the mold cavity increases, the air in the mold cavity is discharged through the exhaust hole, and the energy-absorbing buffer layer is squeezed and attached to the surface of the pre-composite layer and the plastic layer. The pre-composite layer and the plastic layer are firmly combined with the energy-absorbing buffer layer to absorb and disperse the instantaneous impact force.

[0076] In the present invention, the foaming and cross-linking integrated molding preferably further includes cutting off excess scraps.

[0077] The leg guard prepared by the invention has the properties of shear thickening, energy absorption and buffering, air permeability and anti-slip, meets the requirements of ergonomics and has high comfort.

[0078] The shin guard of the present invention adopts a mold with a longitudinal ventilation channel and a concave-convex curved surface design (ergonomic design), applies anti-slip technology, and uses casting and composite molding integrated technology to ensure the safety of the football shin guard during use (not easy to slide), greatly improving the protective safety, fit, breathability and wearing comfort of the protective gear during sports.

[0079] In order to further illustrate the present invention, the leg guard and the preparation method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0080] In the embodiment 1 of the present invention ～ 3, the NNF raw materials used include premix and curing agent, and the preparation method is as follows:

[0081] 1) Preparation of compound chain extender: 50g of diethanolamine, 130g of ethylene glycol, 320g of 3-methyl-1,5-pentanediol and 500g of 1,4-butanediol were added in a constant temperature container at 80°C in sequence, stirring was started and the stirring speed was maintained at 100rpm, the container was sealed, vacuum dehydration was started, and a negative pressure of -0.1MPa was maintained for 8 hours to obtain the first component. According to the molar ratio of hydroxyl group in the first component to isocyanate group in liquefied MDI of 100:45, liquefied MDI was slowly added to carry out polymerization chain extension reaction for 8 hours, heating and stirring were stopped, and the compound chain extender (NNF-1) was obtained when the material temperature dropped to room temperature.

[0082] 2) Preparation of premix: Add 500 g of 1000 molecular weight polyether diol into a 75°C constant temperature container; start stirring and maintain the speed at 100 rpm, then add 100 g of the NNF-1 compound chain extender described in step 1), silane coupling agent (XIAMETER тмOFS-6020Silane) 20g, polysiloxane-olefin oxide block copolymer emulsifier 10g, nano white carbon black (AEROSIL200) 200g; continue stirring for 45 minutes, stop heating, add 200g 2000 molecular weight polyether diol, 330g 5000 molecular weight polyether triol, 10g triethanolamine, 8g dimethylethanolamine as foaming catalyst and 5g triethylenediamine as curing catalyst, continue stirring; add 2.5g foaming agent (deionized water) when the temperature drops to 30°C; keep stirring for 30 minutes and stop stirring to obtain a premix, and the temperature is controlled at 25°C. The polyether diol is C2010 and the polyether triol is 330N.

[0083] 3) Preparation of curing agent:

[0084] According to the molar ratio of hydroxyl group in the premix to isocyanate group in the curing agent of 1:1.01, weigh the liquefied MDI and add it to another container. The temperature is controlled at 35°C.

[0085] The premix and curing agent were mixed at a high speed of 4000 rpm for 10 seconds before use.

[0086] Example 1

[0087] 1. Pre-lamination of anti-slip fabrics

[0088] First, the elastic material PVC is attached to the outer surface of the spandex fabric substrate with a thickness of 0.1 mm by a drop molding process to form a honeycomb outer surface layer with anti-slip performance (elastic anti-slip structure layer, skin-fitting layer) with a thickness of 0.5 mm;

[0089] At 160° C., a 0.03 mm thick stretchable TPU film (82A) with elastic anti-seepage properties is thermally laminated on the inner surface of the spandex fabric substrate to obtain an inner surface layer. According to the size requirements of the leg guard molding mold, the obtained pre-laminated layer with anti-slip properties is cut into pieces for later use.

[0090] 2. Casting composite integrated molding

[0091] Mold preparation: prepare a shin guard mold with a ventilation channel and ergonomic design. The mold has a quick locking function (install a quick locking fixture); there is an exhaust channel with a diameter of 1mm at the top (highest point) of the mold cavity; control the mold temperature at 50℃; evenly spray the release agent on the surface of the mold cavity for use.

[0092] The cut pre-composite layer is placed in the upper cavity of the mold, and the pre-injection-molded PP plastic shell (thickness 2.0 mm) is placed in the lower cavity of the mold for use.

[0093] The pre-prepared NNF raw material is injected into the cavity in an amount calculated according to the size, thickness and density of the small mold; the mold is closed and locked.

[0094] The product was cured at 60°C in the mold cavity for 7 minutes, and the mold was opened to take out the product. The excess scraps were cut off along the periphery of the shin guard with scissors to obtain a multi-layer composite football shin guard, denoted as NNF-SA-S, which has shear thickening, energy absorption and cushioning, and breathable properties, meets ergonomic requirements, and is highly comfortable.

[0095] Example 2

[0096] 1. Pre-lamination of anti-slip fabrics

[0097] First, the elastic material PVC is attached to the outer surface of the polyester fiber substrate with a thickness of 0.1 mm through a drop molding process to form a 0.5 mm thick wavy outer surface layer (skin-fitting layer) with anti-slip performance;

[0098] At 180° C., a 0.03 mm thick stretchable TPU film with elastic anti-seepage properties is thermally laminated on the inner surface of the substrate to obtain an inner surface layer. According to the size requirements of the leg guard molding mold, the obtained pre-laminated layer with anti-slip properties is cut into pieces for later use.

[0099] 2. Casting composite integrated molding

[0100] Mold preparation: prepare a shin guard mold with a ventilation channel and ergonomic design. The mold has a quick locking function (install a quick locking fixture); there is an exhaust channel with a diameter of 1.0mm at the top (highest point) of the mold cavity; set the mold temperature at 50℃; evenly spray the release agent on the surface of the mold cavity for use.

[0101] The cut pre-composite layer is placed in the upper cavity of the mold, and the pre-injection-molded plastic shell (thickness 2.0 mm) is placed in the lower cavity of the mold for use.

[0102] Inject the pre-prepared NNF raw material into the cavity in an amount calculated according to the size, thickness and density of the medium-sized mold; close and lock the mold.

[0103] The product is cured in the mold cavity for 8 minutes, the mold is opened and the product is taken out, and the excess scraps are cut off along the periphery of the shin guard with scissors to obtain a multi-layer composite football shin guard, which is denoted as NNF-SA-M. It has shear thickening, energy absorption and cushioning, and breathable properties, meets ergonomic requirements, and is highly comfortable.

[0104] Example 3

[0105] 1. Pre-lamination of anti-slip fabrics

[0106] First, the elastic silicone is attached to the outer surface of a polyester fiber substrate with a thickness of 0.1 mm through a printing process to form a 0.5 mm thick wavy outer surface layer (skin-fitting layer) with anti-slip properties;

[0107] At 180° C., a 0.03 mm thick stretchable TPU film with elastic anti-seepage properties is thermally laminated on the inner surface of the substrate to obtain an inner surface layer. According to the size requirements of the leg guard molding mold, the obtained pre-laminated layer with anti-slip properties is cut into pieces for later use.

[0108] 2. Casting composite integrated molding

[0109] Mold preparation: prepare a shin guard mold with a ventilation channel and ergonomic design. The mold has a quick locking function (install a quick locking fixture); there is an exhaust channel with a diameter of 1.0mm at the top (highest point) of the mold cavity; set the mold temperature at 55℃; evenly spray the release agent on the surface of the mold cavity for use.

[0110] The cut pre-composite layer is placed in the upper cavity of the mold, and the pre-injection-molded plastic shell (thickness 2.0 mm) is placed in the lower cavity of the mold for use.

[0111] Inject the pre-prepared NNF raw material into the cavity in an amount calculated according to the size, thickness and density of the large-sized shin guard mold; close and lock the mold.

[0112] The product is cured in the mold cavity for 9 minutes, and the mold is opened to take out the product. The excess scraps are cut off along the periphery of the shin guard with scissors to obtain a multi-layer composite football shin guard, which is denoted as NNF-SA-L. It has shear thickening, energy absorption and cushioning, and breathable properties, meets ergonomic requirements, and is highly comfortable.

[0113] The leg guard of the present invention is manufactured by integral molding of a mold designed based on the statistical data of the tibia plaster model, and the shape, curvature and thickness of the product conform to the ergonomic design. Taking NNF-SA-M as an example, Figure 2 The product diagram of the right leg shin guard is shown, with the left side showing the front and the right side showing the skin-fitting surface. The front side is smooth, which ensures accurate ball control when kicking; the skin-fitting surface has an ergonomic curved surface and is anti-slip and breathable. Figure 3The thickness dimensions of multiple points other than the plastic shell are marked in the figure (the thickness is indicated by a dotted line, and the unit is mm). The left figure is the lower curved surface, and the right figure is the upper curved surface. The right figure marks the thickness of 8 points on the upper curved surface with a distance of about 30 to 50 mm; the left figure marks the thickness of 7 points on the lower curved surface with a distance of 30 to 50 mm and 4 points with a cross-sectional distance of about 50 mm. It can be seen from the figure that the upper curved surface has a larger curvature and a higher thickness than the lower curved surface; the outer side of the upper curved surface leg (right figure) has a larger curvature and a higher thickness than the inner side. The product is integrally formed, seamless and hard edgeless, flexible and bendable, and highly comfortable to wear.

[0114] The schematic diagram of the football shin guard product obtained in Examples 1 to 3 is as follows Figure 4 The dimensions are shown in Table 1 below:

[0115] Table 1 Specifications of mold dimensions

[0116] Mould small Medium large size 176×92mm 198×108mm 215×109mm Product Name NNF-SA-S NNF-SA-M NNF-SA-L

[0117] Test Example 1

[0118] The football shin guard products obtained in Examples 1 to 3 were sent for testing according to the requirements and test method EN 13061-2009 for shin guards of the European Football Players Association, and various indicators such as impact resistance, safety performance, ergonomics and human non-toxicity tests were certified.

[0119] Among them, the impact energy absorption performance has reached a very high level, that is, the permeability value is 0.2-0.4 kN, as shown in Table 2 below, which is the permeability value of six test points (B1, B2, B3, B4, B5, B6) of the large sample (NNF-SA-L), which is far lower than the EU EN 13061 requirement of less than 2.0 KN for shin guards, indicating that the football shin guards obtained by the present invention have excellent energy absorption and buffering effects.

[0120] Table 2 Transmission values ​​of six test points of NNF-SA-L

[0121]

[0122] Requirements: In the center or side test area, the three single penetration force values ​​at the same point shall not exceed 2.0 kN.

[0123] The safety performance also achieved good results. As shown in Table 3 below, when subjected to impact force, the displacements of the five points of sample NNF-SA-L (left upper, right upper, left lower, right lower, top in the table) were far lower than the requirements of the European Football Players Association for shin guards.

[0124] Table 3 Displacement of five points of NNF-SA-L

[0125] Testing Point Max displacement permitted Shin Guard Movement P F N / A Upper Left 18mm 6mm √ Upper Right 18mm 6mm √ Lower Left 15mm 4mm √ Lower Right 15mm 5mm √ Top 30mm 11mm √

[0126] Requirements: The displacement of the shin guard from its initial position shall be less than 15 mm, or if greater than 15 mm, shall be less than 15% of the linear dimension of the test area measured against the applied force.

[0127] The S and M size shin guards have similar performance, and the anti-slip performance is good as can be seen from the displacement in Table 3 Safety Performance.

[0128] Comparative Example 1

[0129] The picture of a shin guard product sold on the market is as follows: Figure 5 As shown, the left side is the front side and the right side is the skin-fitting side. It can be seen from the figure that there are a few ergonomically designed protrusions on the front side, which are easy to form stress concentration points, easy to crack, and not conducive to precise control of direction when kicking the ball; the skin-fitting side has no ergonomic design, no breathable channels, and no anti-slip structure; the product has uniform thickness, no bumps, and no peripheral curved surface design, which does not meet ergonomic requirements; moreover, since it is not an integrated molding, the hard edges formed by the stitching lines can be observed on the periphery of both sides, which also makes the entire product not flexible and cannot bend. It is easy to crack during use and easily wears the skin, reducing the comfort of wearing.

[0130] The room-temperature permeability of a certain shin guard product sold on the market is 36.5 kN. The high permeability indicates that the energy absorption performance is not ideal, and the human body is easily injured when subjected to a large impact force.

[0131] The shin guards of the present invention have good energy absorption and shock absorption effects. When the impact force is large, the energy absorption and buffering materials can quickly gather, giving high impact resistance and high energy absorption characteristics, achieving the effects of damping, energy absorption, and vibration reduction; when the impact force is released, the material will return to its original relaxed soft elastic state. The energy absorption performance of the shin guards of the present invention meets the EU certification requirements for impact resistance tests, and the average penetration value is far less than the 2.0kN index, within the range of 0.2 to 0.4kN. The shin guards of the present invention are flexible and fit, and are ergonomic. The ergonomic test meets the requirements of the Football Players Association for shin guards and the test requirements of 3.2 & 4.5 Ergonomics in the test method EN13061. The safety performance test of the shin guards of the present invention meets the requirements of the Football Players Association for shin guards and the test requirements of 3.4 Restraint in the test method EN 13061. At the same time, the shin guards of the present invention have good anti-slip and breathable properties.

[0132] Test Example 2

[0133] The differences from the NNF raw materials used in Examples 1 to 3 are: 1) Preparation of the compound chain extender: according to the molar ratio of hydroxyl groups in the first component to isocyanate groups in the liquefied MDI of 100:50, 2) Preparation of the premix: 300 g of 5000 molecular weight polyether triol; 3) Preparation of the curing agent: according to the molar ratio of hydroxyl groups in the premix to isocyanate groups in the curing agent of 1:1.05.

[0134] The NNF layers were prepared by using the above NNF raw materials (comparative NNF layers) and the NNF raw materials used in the examples, Figure 6 The NNF liquid used in the embodiment of the present invention reduces the proportion of isocyanate groups in the hard segment and relatively increases the proportion of polyols in the soft segment, thereby improving the flexibility of the product, and the elongation at break reaches 120%, which can better meet the ergonomic requirements of football shin guards and improve wearing comfort.

[0135] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A leg guard, characterized in that: It is a curved structure, the outer surface is smooth as a whole, and the inner surface is provided with a ventilation channel; The leg guard comprises an elastic anti-slip structure layer, a fiber base material layer, an elastic anti-seepage layer, an energy-absorbing buffer layer and a plastic layer which are sequentially stacked from the inside to the outside; The energy absorbing buffer layer comprises shear thickening polyurethane, and the raw materials for preparing the shear thickening polyurethane comprise a premix and a curing agent; The premix comprises the following components in parts by weight: 30-80 parts of polyether diol, 20-70 parts of polyether polyol, 1-20 parts of chain extender, 0.5-3 parts of cross-linking agent, 5-50 parts of filler, 0.5-5.0 parts of coupling agent, 0.05-15 parts of foaming agent, 0.1-5.0 parts of emulsifier, and 0.05-5.0 parts of catalyst; the number of hydroxyl groups of the polyether polyol is more than 3, and the hydroxyl value of the polyether polyol is 22-56 mg KOH / g; The curing agent includes but is not limited to isocyanate or modified isocyanate; The molar ratio of the hydroxyl group in the premix to the isocyanate group in the curing agent is 1:1 to 1.

1.

2. The leg guard according to claim 1, characterized in that: The thickness of the energy absorbing buffer layer is 4 to 10 mm.

3. The leg guard according to claim 1, characterized in that: The elastic anti-slip structural layer is made of an elastic material, and the elastic material includes but is not limited to polyvinyl chloride, thermoplastic polyurethane, TPR, TPS, TPO or silicone.

4. The leg guard according to claim 1 or 3, characterized in that: The thickness of the elastic anti-slip structural layer is 0.3-1 mm, and the structure of the elastic anti-slip structural layer includes but is not limited to honeycomb, wave, stripe or dot geometric or non-geometric structures.

5. The leg guard according to claim 1, characterized in that: The material of the fiber substrate layer includes but is not limited to Lycra, spandex or polyester.

6. The leg guard according to claim 1 or 5, characterized in that: The thickness of the fiber substrate layer is 0.06-0.3 mm.

7. The leg guard according to claim 1, characterized in that: The elastic anti-seepage layer includes but is not limited to a TPU film.

8. The leg guard according to claim 1 or 7, characterized in that: The thickness of the elastic anti-seepage layer is 0.01-0.1 mm.

9. The method for preparing the leg guard according to any one of claims 1 to 8, characterized in that: The following steps are involved: The elastic anti-slip material is attached to the surface of one side of the fiber substrate layer, and the surface of the other side of the fiber substrate layer is thermally laminated with the elastic anti-seepage membrane to obtain a pre-laminated layer; The raw materials for preparing the energy-absorbing buffer layer are poured between the pre-composite layer and the plastic layer, and foaming and cross-linking are performed for integrated molding to obtain the leg guard.

10. The preparation method according to claim 9, characterized in that: The temperature of the foaming, cross-linking and integrated molding is 35 to 80° C. and the time is 2 to 10 minutes.

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