Abstract:
A 3-dimension (3D) multi-layer composite comprises a first sheet layer with fastening components on at least one side of the first sheet layer, a second sheet layer with fastening components on both sides of the second sheet layer, and a third sheet layer with fastening components on at least one side of the third sheet layer, wherein the second sheet layer is positioned adjacent to and between the first sheet layer and the third sheet layer, wherein the fastening components on the one side of the first sheet layer engage with the fastening components on one side of the second sheet layer, wherein the fastening components on the one side of the third sheet layer engage with the fastening components on the other side of the second sheet layer, and wherein the engaged fastening components enhance interlayer strength.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/854,632, filed on Oct. 27, 2006. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to 3 dimension (3D) fibers, 3D fabrics, 3D preforms, 3D prepregs and 3D composites and methods to make them using textile industry technologies, hook and loop technologies, plastic industry technologies and nano-fiber technologies, with the objects to increase their mechanical strength, interlaminate strength, fatigue durability and impact resistance, and their manufacturability. 
     BACKGROUND OF THE INVENTION 
     Fiber composite materials have been used in the industry over the past three decades. However, their utilization in the primary load-bearing structures has been limited by its high sensitivity to out-of-plane failures resulting from the low interlaminar fracture toughness. Method to alleviate these problems is to improve delamination resistance in the thickness direction by stitching, 3D weaving, 3D knitting, 3D braid. Those 3D technologies need complicated machines and manufacturing processes. So layer-by-layer lay-up and filament wrapping are still major processes in composite industry. 
     The present invention provides methods to make 3D composites in compatible to 2D manufacturing process. 
     SUMMARY OF THE INVENTION 
     The present invention is to provide methods to make 3 dimension (3D) fibers, 3D fabrics, 3D preforms, 3D prepregs and 3D composites, by using hook and loop (VELCRO), hook and hook, zipper heads, fish hook, and/or arrow head and mushroom head fastening components, across layers, strands and yarns. One sheet of fibers has one or multiple kinds of the above said fastening components on one side and their fastening counterparts on the other side. Laying up the sheets with said fastening components on its two side as regular 2D sheets can obtain a 3D preform. The sheets can be torn apart if re-lay-up is needed. A fiber or yarn can have the said fastening components around 360 degree on its surface. Laying up the fibers and yarns with said fastening components together or intercrossing each other can get a 3D preform. In those preforms, two parts of the said fastening components can lock each other if they meet and engage. A 3D composite structure can be made by using the 3D preform in resin infusing, resin film infusing, resin protrusion or RTM. The fastening components can be arranged in pattern arrays to increase strength against specified loads. 
     One weaved or non-weaved sheet of fiber with the said fasteners on both sides or a yarn is first impregnated with resin. Then let the impregnated fiber sheet or the yarn dry. A piece of prepreg with the said fasteners or a yarn prepreg is then made. Finally, lay and press the prepreg sheets together to any desired thickness. The fastening component can lock each other if they meet and engage. In a curing process, the resin can melt and the fastening components can further interlock each other. So a 3D composite structure is made by the said 3D prepregs. Wrapping the yarn prepreg can get a 3D composite too. 
     The fastening components of hook and loop (VELCRO), hook and hook, zipper heads, fish hook, arrow head and mushroom head can be made onto the sheet fiber (weaved or non-weaved), strands and yarns by textile industry technologies, such as weaving, knitting, warp knitting, braid, stitching, and hook and loop (VELCRO) technologies, and by non-weaving technologies, such as needle penetrating, air-blowing fasteners on fibers and air- or water-jet shooting fasteners on fibers. The fastening components can be bonded on, glued on, welded on, compressed on, or grown on the fibers. 
     The two parts of fastening components can have acute angles to their base sheet or fibers. The acute angle can allow the two part fastening components to engage like sharp teeth to increase their locking. The fastening components can be made from all kinds of suitable materials including nano fibers, strands and filaments, nanotubes, nano forks, and nano arrows. 
     This 3D fiber technology can be used in rubber, building materials and plastic industries. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows a view of an exemplary sheet of fibers with hook, loop and other fastening components on its both sides. 
         FIG. 2  shows a view of an exemplary composite made by the fiber sheets with fastening components. Several of sheets make the preform and composite. The trans-layer fastening components make a 3D composite. 
         FIG. 3  shows a view of an exemplary 3D prepreg sheet with hook, loop and other fastening components on its both sides. 
         FIG. 4  shows a cross-section view of the 3D prepreg of  FIG. 3 . 
         FIG. 5  illustrates an exemplary process of using mold to control the hook, loop and fastening fibers shape, direction, and angle or using chemical air to obtain the shape and angle and direction of the fastening fibers. 
         FIG. 6  shows a view of exemplary trans-layer hook and loop fibers. 
         FIG. 7  illustrates an exemplary process of using laser to cut loops to get hooks. 
         FIG. 8  illustrates an exemplary process of using laser and heat iron to make hooks. 
         FIG. 9  shows variety of exemplary hooks. Several fibers are yarned and bonded together by glue to make the hooks stiffer. 
         FIG. 10  shows variety of exemplary loops. 
         FIG. 11  shows a transparent view of an exemplary block of composite made from 3D forks and branches. 
         FIG. 12  shows exemplary filaments having hook and loops and other fastening components. 
         FIG. 13  shows an exemplary pressure bottle made from filaments with fastening components. 
         FIG. 14  shows an exemplary vest made from the 3D composites. 
         FIG. 15  shows an exemplary helmet made from 3D composites. 
         FIG. 16  shows an exemplary stem fiber having 3 dimension branches and forks. 
         FIG. 17  shows an exemplary networking of 3D branches and forks. 
         FIG. 18  shows 3D branch, hook directions in an exemplary composite. 
         FIG. 19  shows exemplary vertical trans-layer and interlayer fibers having acute angles along their long direction. The acute angle vertical fibers can bite into each other and engage. This locking can have stronger strength against shear load and tear load. 
         FIG. 20  shows a view of an exemplary composite having acute hooks at different directions. 
         FIG. 21 . shows an exemplary view of acute angle hooks and loops interlocking between fiber layers. 
         FIG. 22  shows an exemplary view of the engagement of hooks and hooks, hooks and loops. 
         FIG. 23  shows an exemplary process of using a spiral screw cylinder to make the hooks, loops and fibers in the curves of spiral spur gear. 
         FIG. 24  shows an exemplary process of using a needle to bring hook and loop fibers trans-layer. 
         FIG. 25  shows an exemplary process of using air blow, air jet, or water jet to shoot hook and loop fibers trans-layer and stay on the layer. 
         FIG. 26  shows the loop on an exemplary woven towel. 
         FIG. 27  shows that small loops are formed on the surface of an exemplary fabric by the use of complex yarns. 
         FIG. 28  shows an exemplary view of patterned knitted fabric loops. 
         FIG. 29  shows the other side of the fabric of  FIG. 28 . Cutting the loops can get hooks. 
         FIG. 30  shows an exemplary view of compressing the hook and loop fabric on a net. 
         FIG. 31  shows an exemplary view of the hook and loop pattern made by embroidery. 
         FIG. 32  shows an exemplary view of loops on a bath towel. 
         FIG. 33  shows an exemplary view of a bath towel with loops. 
         FIG. 34  shows an exemplary process of cutting the fiber to get the hooks. 
         FIG. 35  shows an exemplary process of obtaining fibers and hooks by napping a yarn. 
         FIG. 36  shows an exemplary view of hooks and loop connecting blankets in the transverse direction. 
         FIG. 37  shows an exemplary view of fiber strands combined with fine simple yarns. 
         FIG. 38  shows an exemplary view of stitch and knit making the loops. 
         FIG. 39  shows an exemplary view of stitch and knit making the loops. 
         FIG. 40  shows an exemplary view of fastening components in belt areas on the sheets. 
         FIG. 41  shows an exemplary view of fastening components in belt areas on the sheets. 
         FIG. 42  shows an exemplary view of carbon nanotubes with varying diameters along length. 
         FIG. 43  shows an exemplary view of adhesive or coating materials holding a bunch of fiber hooks together. 
         FIG. 44  shows an exemplary view of a group of fiber loops on a sheet. 
         FIG. 45  shows an exemplary process of using a flocking process and a modified flocking process to prepare vertical short fibers on fiber sheet or other substance surface. 
         FIG. 46  shows an exemplary process of a flocking application by an electrostatic method. 
         FIG. 47A  shows an exemplary view of the fiber sheet net and adhesive net film with a designed pattern on them. 
         FIG. 47B  shows an exemplary view of the fiber sheet net and adhesive net film with a designed pattern on them. 
         FIG. 48  shows an exemplary view of the adhesive net films attached to the two sides of fiber sheet. 
         FIG. 49  shows an exemplary view of the fiber sheets with flocked vertical fibers. Loops and hooks are stacked together. 
         FIG. 50  shows an exemplary process of flocking fibers on adhesive film and transferring on fibers. 
         FIG. 51  shows an exemplary view of a net having hooks, loops and mushroom heads on its both sides. 
         FIG. 52  shows an exemplary process of using complex yarn technology to make the yarns. 
         FIG. 53  shows an exemplary view of the yarn with varying width along its length. 
         FIG. 54  shows an exemplary view of wider yarns making the tube and bottle curve area stronger. 
         FIG. 55  shows an exemplary view of the hook, loop, mushroom head and fastening components attached on yarns just like the barb on a barbed wire. 
         FIG. 56  shows an exemplary process of using stables to make 3D preforms and composites. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a sheet  10  of fibers or film has hook  11 , loop  12 , anchor-like hook  13 , fish hook  14 , fork  17  and  21 , big head  18 , arrow-like hook  19  and group loop  20  fastening components on both sides of the sheet. A hook can have multiple hooks  15  and  16  like a hook string. The fastening components can form a pattern or an array on the sheet with specified directions. The fastening components can be randomly scattered or mixed on the sheet. 
     As shown in  FIG. 2 , several sheets  10  can be laid together layer-by-layer to form a preform  30 . The hook and loop, hook and hook and other fastening components can engage each other to provide trans-layer and interlayer reinforcements. The top and bottom sheet can have fastening components on only one side of the sheets. 
       FIG. 3  shows that resin  35  infiltrates the fiber sheet  10  to form a piece of prepreg  33 .  FIG. 4  shows a cross-section view of prepreg  33 . The hook and loop, and fastening components  37  and  38  can be above the resin and stand out of the sheet, or can stay right under the resin surface. The fastening components can engage each other when the resin becomes liquid during curing. The resin  35  can have a low step  36  where fastening components are lower than the surrounding resin. The fastening components can be protected by the higher surrounding resin. 
       FIG. 5  illustrates an exemplary process of using mold and chemical air to obtain the hook, loop and fastening component shape, direction, angle and dimension. 
       FIG. 6  is a section view of trans-layer hook and loop fibers. They can be made by textile industry technologies, such as weaving, knitting, warp knitting, braid, stitching, by hook and loop (VELCRO) technologies, and by non-weaving technologies such as needle penetrating, air-blowing fasteners on fibers, and air- or water-jet shooting fasteners on fibers. The fastening components can be bonded on, glued on, welded on, compressed on, and grown on the fibers. 
       FIG. 7  shows an exemplary process of using laser to cut the loops to get hooks. Knife also works to cut the fibers to get hooks. 
       FIG. 8  shows an exemplary process of using laser and heat iron to treat the fibers and make the hooks and loops in a specified direction and angle. 
     Some embodiments of the hooks a 1 -a 28  are illustrated in  FIG. 9 . Hook  40  (a 2 -a 4 ) can have several fibers bonded together by adhesive  41  to make the hook much stiffer. Hook  42  can have several short fibers and several long fiber bonding together. Those hook  11 , anchor-like hook  13 , fish hook  14 , fork  17  and  21 , big head  18 , arrow like hook  19  and group loop  20  fastening components are also shown in  FIG. 1 . 
     Some embodiments of the loops b 1 -b 9  are illustrated in  FIG. 10 . 
       FIG. 11  shows that the rod/fiber  45  can have branches  46  coming out of itself at any direction. Fiber  45  and branch  46  can be made of different materials. The fibers  45  are aligned together and their branches  46  are cross-linked together. Therefore a 3D preform is made. The sheets can be torn apart if re-lay-up is needed. Infiltrating a 3D preform with resin can get a 3D composite. 
       FIG. 12  shows that yarns (a)-(f) can have hooks and loops and other fastening components. They can be made by complex yarn technology, by barbed wire entanglement technology, and by air blow technology. Air blow and jet or water jet can shoot the fastening components on the yarns. The yarns are then infiltrated by resin  35  to get yarn prepregs. 
     A bottle can be made by wrapping said yarns or yarn prepreg, as shown in  FIG. 13 . The yarn can vary its width  76  along its length. A wider yarn or belt  76  can make the curve area stronger. The fastening components can engage during wrapping. So a bottle is made with higher impact resistance 3D composite. 
     3D composites can be used to make vest and helmet to protect people, as shown in  FIG. 14  and  FIG. 15 . 
       FIG. 16  shows that a rod, yarn, or fiber  50  can have branches  51  and forks  53  coming out from its stem and standing out to the space around the stem in 3 dimensions. Part of the branch  51  can have curve  52  acting as a hook. The part  52  can be in the same material as branch  51  or in other material bonded to branch  51 . The fork  53  on branch  51  is sub-branches. The sub-branch  53 , knot  54  and arrow-like tooth  55  on branch  51  or even stem  50  can act as fastening components. Tooth  55  can have a sharp face  56 . 
       FIG. 17  shows that several fibers  50  can engage together by their branches  51  and the fastening components on their branches. 
     The acute angle  57  of branch to stem can help the engagement of branches to increase the engagement chance and strength. The sub-branch  53  is short enough for penetrating and long enough for acting as a hook. An acute angle  57  of the sub-branch can help the penetrating. The acute angle  58  of branch to the interlayer straight distance line  59  can also be important to the engagement. 
       FIG. 18  shows the fibers  50  in fiber sheets. When the fiber sheets are laid up together, the branches  51  and their fastening components can engage and interlock together to form 3D preform, prepreg and composite. The branches can have back-to-back and face-to-face engagement due to the acute angel  57  direction (branch direction), which helps to increase the strength against sheer and tear load. 
       FIG. 19  is a section view showing fibers&#39; face-to-face engagement of fastening components. An acute angle fiber or branch faces another fiber or branch in acute angel. 
       FIG. 20  shows several fiber sheets laid up together. Some areas of the sheets can have the same direction of fastening components (branch, hook, loop), marked by arrow  60 . A sheet with different direction of fastening components can make the composite have good strength against different direction load. 
     A face-to-face lock is illustrated in  FIG. 21 , just like sharp teeth bitten together. The fastening components with acute angles are important in controlling the fastening direction when the fiber sheets are compressed. 
       FIG. 22  shows that hooks, loops and fibers can be made in the curves of a spiral spur gear or a spiral screw cylinder. Those curves help the hooks and loops engagement. 
       FIG. 23  shows an exemplary process of using a spiral screw cylinder  62  to make the hooks, loops and fibers in the curves of spiral spur gear  63 . 
       FIG. 24  shows an exemplary process of using needles  64  to bring hook and loop fibers trans-layer. 
       FIG. 25  shows an exemplary process of using air blow, air jet, or water jet  65  to shoot hook and loop fibers trans-layer and staying on the layer. 
       FIG. 26  shows the loops on a woven towel. 
       FIG. 27  shows small loops are formed on the surface of the fabric by the use of complex yarns. 
       FIG. 28  shows patterned knitted fabric loops. 
       FIG. 29  shows other side of the fabric of  FIG. 28 . Cutting the loops can get hooks. 
       FIG. 30  shows compressing the hook and loop fabric on a net  66 . 
       FIG. 31  shows the hook and loop pattern made by embroidery. 
       FIG. 32  shows loops on a bath towel. Terry cloth, used in towels and robes, is constructed with uncut loops of yarn on both sides of the sheet cloth. These loops are formed by holding the ground wrap yarns under tight tension and leaving the wrap yarns that form the pile in a slack state. The shed is made and picks are inserted. And this is repeated for a specified number of picks, usually three, without any beating in. After the picks have been placed, they are battened into position. This causes the slack wrap yarns to be pushed into loops between the picks. While the typical terry cloth has loops on both sides, it is possible to make fabrics by this method with loops on only one side. Hook yarns are recommended to be stiff. And loop yarns are softer. 
       FIG. 33  shows a bath towel with loops. 
       FIG. 34  shows cutting the fiber to get the hooks. 
       FIG. 35  shows obtaining the fibers and hooks by napping a yarn  67 . 
       FIG. 36  shows hooks  11  and loop  12  connecting blankets in the transverse direction. 
       FIG. 37  shows fiber strands are combined with fine simple yarns. 
       FIG. 38  and  FIG. 39  show that stitch and knit make the loops. 
       FIG. 40  and  FIG. 41  show the fastening components can be in belt areas on the sheets. So the two sheets can easily engage in the belt areas. 
       FIG. 42  illustrates that the carbon nanotubes can have big head  23  at its ends. The big heads are the end areas having bigger diameters. The big diameter tube area can be single layer tube and/or multiple tube layers. The big diameter area can be located along the tube like a chain. Two big diameter areas  24  can hold the tube on a fabric or a thread. The bigger diameter areas can have one end with sharp edge  25  acting as hook and another end with smooth cure  26  acting as a bullet head for penetrating fibers and loops. 
       FIG. 43  shows adhesive or coating materials  27  holding a bunch of fiber hooks  22  together to make the hook stronger and stiffer. Those stiffer hooks are easier to penetrate fiber loops and bundles to lock with them. 
       FIG. 44  shows a group of fiber loops  20  on a sheet  10 . 
       FIG. 45  shows an exemplary process of using a flocking process and a modified flocking process to prepare vertical short fibers on fiber sheet  10  or other substrate surface  18 . The flocking process involves applying short fibers  11 , fiber bundles  22  and bonded fibers  27  directly on to a substrate that has been previously coated with an adhesive. The process uses mechanical or electrical equipment that mechanically erect or electrically charges the flock short fibers causing them to stand up. The short fibers are then propelled and anchored into the adhesive at near right and right angles to the substrate. The flocking process can be accomplished by one of the four methods: electrostatic, beater bar/gravity, spraying, and transfers. Flocking material can also be spayed using an air compressor, reservoir and spay gun similar to the one spaying paint. Flocking can also be applied by printing an adhesive on to a material, and then rapidly vibrating the substrate mechanically, while the flock fibers are dispensed over the surface. 
     The vibration promotes the density of fibers and causes the flocking fibers to adhere to the adhesive and pack into a layer. This process is a beater bar or gravity flocking system. 
       FIG. 46  shows a flocking application by the electrostatic method. The fiber sheet  10  goes between positive electrode grid  73  and ground electrode  72  to let flocking short fibers penetrate fiber sheet and adhesive film and stay on them. Adhesive standoffs  71  are provided in between the fiber sheet  10  and the adhesive net film  70  so as to create a gap between the fiber sheet  10  and the adhesive net film  70 . The same arrangement is illustrated in  FIG. 45 . 
     In  FIGS. 47A and 47B , the fiber sheet  10  is attached to an adhesive net film  70  underneath. The adhesive on the net film attach to the fiber sheet  10  and make a gap between the adhesive net film and fiber sheet. 
       FIG. 48A  and  FIG. 48B  show the adhesive net films  70  can be attached to the two sides of fiber sheet  10 . The adhesive film  70  has window  74  to allow short flocking fibers to penetrate fiber sheet  10  and stay at desired areas. 
       FIG. 49  shows the fiber sheets with flocked vertical fibers, loops and hooks are stacked together. During curing process, the adhesive melt and the hooks and loops link together. 
     A much easier way to add flocking to materials is to apply standard flocking transfers. Basically the flocking process is virtually the same as the one for a screen printing with only a few differences.  FIG. 50  shows the short fibers are flocked on adhesive film  70  and then transfer onto the fiber sheet  10 . 
     If the short fibers are dielectric, a chemical treatment is needed to enable the fibers to accept an electrical charge. A certain amount of conductivity must be present for electrostatic flocking process to occur. 
       FIG. 50  shows flocking fibers on adhesive film and transferring them on fiber sheets. 
       FIG. 51  shows a net  75  has hooks, loops and mushroom heads on its both sides. The hooks, loops and mushroom heads can go through fiber sheet  10  to link with next net  75  when the nets  75  and fiber sheets stack together. 
       FIG. 52  shows using complex yarn technology to make the yarns. The hooks or mushroom heads can have multiple stands  22  and be bonded with material  27  to make them stronger and harder. 
       FIG. 53  shows a yarn can vary its width  76  along its length. So the wider yarn or even belt  76  makes the tube and bottle curve area stronger, as shown in  FIG. 54 . 
     The hooks, loops, mushroom head and fastening components can attach on yarns just like the barb on a barbed wire, as shown in  FIG. 55 . 
     Stables can also be used to make 3D preforms and composites, as shown in  FIG. 56 . Threads  22  can become a stable with adhesive  27 . Using a regular stable machine and a flocking process can let the thread stables penetrate fiber sheets to make 3D preforms and composites.