• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2000.11a
• /
• pp.50-53
• /
• 2000

The effect of punching density on the mechanical and thermal properties of nonwoven needle-punched carbon/phenol composite was studied. The carbonized preforms were farmed into composites with phenol resin. The interlaminar shear, tensile and flexural strengths were increased with increasing punching density. However, excessive punching density decreased interlaminar shear and tensile strengths. Erosion rate of carbon/phenol composite was decreased with increasing punching density

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.63-66
• /
• 2003

The effect of punching density and material composition on the tensile properties and optimum condition of manufacturing of carbon needle punched perform was studies. The interlaminar tensile strength were increased but the intralaminar tensile strength were decreased with increasing punching density. In the case of the performs composed of continuous oxi-PAN fabrics, there was a considerable improvement of the interlaminar and intralaminar tensile strength.

• Proceedings of the Korean Fiber Society Conference
• /
• 1998.10a
• /
• pp.414-417
• /
• 1998

Needle punching is a process for converting fiber webs into coherent structures by using barb needles. The results are the mechanical interlocking of fibers into webs. Nonwovens by needle punching is most versatile among the various methods and is widely used in the industry. The original process for the production of mechanical bonds in nonwoven fabrics is that which employs the natural felting characteristics of the wool fiber. (omitted)

• Proceedings of the Korean Fiber Society Conference
• /
• 1996.10a
• /
• pp.423-426
• /
• 1996

• Elastomers and Composites
• /
• v.57 no.4
• /
• pp.157-164
• /
• 2022

Representative bulletproof materials, such as aramid or ultra-high molecular weight polyethylene(UHMWPE), have excellent strength and modulus in the plane direction but are very vulnerable to forces applied in the thickness direction. This paper reports a study on the effects of reinforcement in the thickness direction when bulletproof composite fabrics are prepared to improve their performance. Aramid and UHMWPE fabrics were combined using the film-bonding, needle-punching, or stitching methods and then subjected to low-velocity projectile and ball-drop impact tests. The results of the low-velocity projectile test indicated that the backface signature(BFS) decreased by up to 29.2% in fabrics obtained via the film-bonding method. However, the weight of the film-bonded fabric increased by approximately 23% compared with that obtained by simple lamination, and the fabric stiffened on account of the binder. Flexibility, light weight for wearability, and excellent bulletproof performance are very important factors in the development of bulletproof materials. When the needle-punching method was used, the BFS increased as the fibers sustained damage by the needle. When the composite fabrics were combined by stitching, no significant difference in weight and thickness was observed, and the BFS showed similar results. When a diagonal stitching pattern was employed, the BFS decreased as the stitching density increased. By contrast, when a diamond stitching pattern was used, the fabric fibers were damaged and the BFS increased as the stitching density increased.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.10a
• /
• pp.176-181
• /
• 1997

During a compression molding of continuous fiber reinforced composites, the separation of matrix and fiber is caused by the flow of the molding process. As the characteristics of the products are greatly dependent on the separation, it is very important to clarify the separation in relation to molding condition, degree of needle punching number on the degree of nonhomogeneity are studied.

• Applied Chemistry for Engineering
• /
• v.20 no.5
• /
• pp.561-564
• /
• 2009

Filter media finely interspersed with activated carbons were prepared by a needle punching process without using chemical binders. Their characteristics were investigated efficiently to abate environmentally harmful gas such as acetaldehyde, and were compared with those of cabin air filter coated with activated carbons by using chemical binders. These combination filters were installed on a vehicle fan placed in a test chamber of capacity similar to the interior volume of a commercially available passenger car, and the efficiency of acetaldehyde abatement was measured as a function of time. The filter utilizing chemical binders showed somewhat better performance for the elimination of acetaldehyde despite the adverse effect of the chemical binder that would clog the micropores of the activated carbons. It turned out that the needle punching process had the activated carbons agglomerated due to hydrophobic interactions, resulting in a relatively larger void area than that of the filter utilizing chemical binders.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11c
• /
• pp.39-55
• /
• 1999

Geotextile composites to improve the weather ability were composed of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method, and evaluated physical properties, ultraviolet resistance and chemical stability. Retention ratio of tensile properties of non woven polypropylene geotextiles were decreased about 50% by the exposed condition with ultraviolet but those of geotextile composites were slightly decreased than polypropylene geotextiles. Geotextile composites which have larger weights of polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile properties of geotextile composites were in the range of -20~＋10% at the various chemical conditions.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.05a
• /
• pp.184-187
• /
• 2002

Compression molding was specifically developed for replacement of metal components with composites. As the mechanical properties of the products are dependent on the separation and orientation, it is important to research the fiber mat structure and molding conditions. In this study, the effects of the fiber mat structure(NP: 5, 10, 25punches/$\textrm{cm}^2$) and the mold closure speed($\dot{\textrm{h}}$=0.1, 1, 10mm/min) on the viscosity of composites were discussed. The composites is treated as a Non-Newtonian power-law fluid. The parallel-plate plastometer is used and the viscosity is obtained from the relationship between the compression load and the thickness of the specimen.

• Journal of Sericultural and Entomological Science
• /
• v.41 no.3
• /
• pp.205-210
• /
• 1999

Silk nonwoven fabrics are prepared by needle punching and thermal bonding with silk waste. To enhance the carding efficiency, the degumming rate was controlled with sodium hydrogen sulfite solution. The amount of the remained sericin was 3%(S-3), and 6%(S-6). Mixing wool and LMP(Low melting polyester) with the silk, to improve carding efficiency, was also effective. Following items were tested with prepared silk nonwovon fabrics : weight, thickness, compression, tensile strength, heat insulation, water absorption, and deodorization. The results show that the silk nonwoven fabrics could be used for apparels and new biomaterials.