Polyethylene Bulletproof Vests Better Than Kevlar 345
teflonscout writes "When I think of bulletproof vests, the first word that comes to mind is Kevlar. Wired is running a story on Dynema SB61, a bulletproof material that is made of polyethylene. It is a higher grade of the plastic found in Tupperware. The story also mentions the recall of Second Chance bulletproof vests that were made from Zylon, a material that degraded slowly when exposed to moisture. At least one police officer was injured when a bullet penetrated his Zylon vest. Polyethylene is impervious to moisture. The first vests made from this new material are 5mm thick and can stop a 9mm bullet traveling at 1777 feet per second, which is slightly better than other top of the line vests."
Re:to bad our troops are treated like shit (Score:4, Interesting)
Yes, don't flame the truth. Rather, flame the complete ignorance of the process by which new technologies trickle down to soldiers from the numerous trials and tests.
If it's good enough, it will eventually be used. The question then will be whether troops will still be in Iraq at that time.
Re:to bad our troops are treated like shit (Score:4, Interesting)
Like the stuff that's good enough that we already have, that to my knowledge, still isn't being used in Iraq?
Maybe it's a few months out of date, but last I heard, the only troops who have bullet resistant body armor over there are the ones who's families bought/shipped it, or got it from an NPO that is buying them and shipping them to the troops.
Re:I'll trust it ... (Score:5, Interesting)
If you haven't heard about the history of "second chance" one of the very first commercial vest manufacturers, that is basically how they sold it. Walk into a police station, pull a gun, shoot oneself at point blank. Put the gun, vest, and business card on the front desk and walk out. As I understand they arrested the founder (Richard Davis) for firing a pistol within city limits, and placed a huge order. He eventually had to quit doing it because all the bruises from the gunshots were starting to give him heart problems.
Re:impervious to water, how about body heat? (Score:2, Interesting)
Second Chance (Score:3, Interesting)
Looked pretty unpleasant -- he immediately fell down, and it took a few seconds before it was clear that he had not, in fact, been shot -- but damned impressive.
Re:Back to the drawing board. (Score:5, Interesting)
combine with liquid armor? (Score:3, Interesting)
But are they really BETTER? (Score:3, Interesting)
Are there any other benefits? Not to underscore the vest's foremost job (stopping bullets) but if there is only a "slight" improvement over existing vests I don't find this all that newsworthy.
Without answers to these questions, these vests will be nothing more than a "slightly better for a lot more money" niche solution.
Cop's widow wins lawsuit over vest - made of Zylon (Score:3, Interesting)
http://www.whistleblowers.org/Cop_s_widow_wins.ht
LoB
Re:impervious to water, how about body heat? (Score:2, Interesting)
Dyneema's also used a lot in rock/mountain climbing gear. Webbing made from it is generally rated to stronger than nylon of the same wieght/size, but it's a lot more susceptible to melting, abrasion, uv exposure, and it's less dynamic.
Re:I'll trust it ... (Score:3, Interesting)
hey, my ph.d. project is on this.. (Score:5, Interesting)
As it happens, dyneema is highly stretched polyethylene. As such, it melts at a fairly low temperature (and performs less well before reaching such temeratures. Temperatures around 80 degrees centigrade would do...). Twaron and Kevlar are aramids. They decompose at around 400 degrees, and hardly any change in performance is seen.
Now, 80 degrees C is a quite high temperature, but with a (desert) sun baking on a vest, I would rather wear the slightly heavier aramid vest.
B.
Re:Actually, the army's tests are in dispute (Score:5, Interesting)
Nor do they cleanly invalidate them. The article plainly states (in several places) that these tests were not the equivalent of the Army tests, and the Dragon Skin vests were not subjected (by the independent investigator) to the full range of enviromental tests that the Army requires.
And repeating MSN's conclusions without (seemingly) understanding the caveats they place on each and every page proves what exactly? That sources you approve of are intrinsically better than sources you disaprove of?
(Disclaimer: I don't much care about the debate either way. Not that the disclaimer will sway anyone - politics are generally more important than intellectual honesty.)
About 20 years late, slashdot (Score:3, Interesting)
Since it's commercialization it has been in wide use throughout the world, and has had performance advantages over aramid fibers like Kevlar. In addition to great performance it is also significatly less expensive, and the manufacturing process has much lower environmental impact.
Re:Back to the drawing board. (Score:5, Interesting)
Re:Actually, the army's tests are in dispute (Score:1, Interesting)
they hired a former 4-star general, another guy who was a ballistics expert working for the army (who was denied access to the army's testing of the vest, ironically), the inventor / CEO of Dragonskin, and another guy who was affiliated high up (used to work for) the company that makes Interceptor body armor, which is currently being used by the ARMY.
They interviewed the Brig commander in charge of armor for the US army, and he said that dragonskin failed miserable when subjected to extreme temperature ranges, partly due to the glue/adhesive used to hold the cucumber-like slices together. The Dragonskin folks deny this.
NBC took the vests to Germany, to some renonwned ballistics lab for independant testing. Granted, Dateline did NOT do ARMY full-on spec testing, because I don't believe that is made public for security reasons. They did, however, fire many different calibers of rounds into both vests (including incindiary rounds) in the exact same locations and measured not only if the bullet went through, but blunt trauma if the bullet was indeed stopped by the vest. In their limited testing, the dragonskin was FAR superious in both stopping power and puncture percentage. They also had testimony from some army specialists who were issued dragonskin (by their commanders/army) for high-importance missions and high-importance escorts.
Not sure if MSNBC has the video, but youtube probably has it somewhere.
-Matt
Re:And new laws to federally prohibit (Score:5, Interesting)
When the spitzer (pointed) bullet was developed in an effort to improve the bullet's aerodynamics and increase range, a secondary effect was discovered. The longer point of the spitzer bullets caused the center of gravity to be pushed more toward the rear of the bullet. This resulted in bullets that were inherently inclined to travel backwards. The gun's rifling was adequate to stabilize these bullets in a point forward orientation through the air, but when they encountered a denser medium (such as a human body) the bullets would tumble as it tried to reorient it's self. The tumbling bullet caused much more sever wounding than the 'icepick' type wounds seen with the older round-nose bullets. Often the combination of tumbling and centrifugal forces (bullets commonly spin in excess of 100,000 rpm) causes the bullet to break into fragments and cause even more nasty wounds (often far worse than what would be seen with soft-point or hollow-point expanding bullets).
Bullet fragmentation is a critical factor in the wounding characteristics of modern military rifle bullets.
Re:Not surprised (Score:3, Interesting)
Re:to bad our troops are treated like shit (Score:1, Interesting)
But if our guys ran into some homies armed with 9mm Glocks, they'd be in business with this type of vest.
But hey, you're on a roll, don't let facts dissuade you from a good rant.
P.S. Yes, these vests might provide some protection against shrapnel from IEDs, but will do jack shit against the concussion and blunt trauma which will kill you just as dead.
Re:Back to the drawing board. (Score:3, Interesting)
That's what Larry Phillips did for the North Hollywood/Laurel Canyon bank robbery in 1997. His arms, legs and neck were also protected, in addition to his abdomen. It weighed 42 lbs.
Certainly that could be lowered some by proper design, but it would still be heavy. And HOT. Imagine wearing the equivalent of a rubber exercise suit out in the middle of summer, and having to chase a bad guy.