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82-482: PLCE may refer to: Personal load carrying equipment , the current tactical webbing system of the British Armed Forces PLCE1 , an enzyme Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title PLCE . If an internal link led you here, you may wish to change the link to point directly to

164-481: A MOLLE belt and under armour Yoke to allow Osprey pouches to be used as belt equipment. After the first introduction in 1989, PLCE in its current MTP form is still Britain's core issue webbing equipment which is compatible with ECBA armour and Mk 6 and 7 helmet, with Osprey issued to non-deployed infantry, leaving Virtus issued to deployed Infantry Commando and Parachute Units. Most other nations are developing, or have developed more modular load bearing systems, such as

246-580: A TB117-2013 tag on furniture, and verify with retailers that products do not contain flame retardants." Liquid resin blends and isocyanates may contain hazardous or regulated components. Isocyanates are known skin and respiratory sensitizers. Additionally, amines, glycols, and phosphate present in spray polyurethane foams present risks. Exposure to chemicals that may be emitted during or after application of polyurethane spray foam (such as isocyanates) are harmful to human health and therefore special precautions are required during and after this process. In

328-537: A U.S. Monsanto / Bayer joint venture, also began making polyurethane chemicals. In 1960 more than 45,000 metric tons of flexible polyurethane foams were produced. The availability of chlorofluoroalkane blowing agents, inexpensive polyether polyols, and methylene diphenyl diisocyanate (MDI) allowed polyurethane rigid foams to be used as high-performance insulation materials. In 1967, urethane-modified polyisocyanurate rigid foams were introduced, offering even better thermal stability and flammability resistance. During

410-569: A blowing catalyst also called A-99. A typical Lewis acidic catalyst is dibutyltin dilaurate . The process is highly sensitive to the nature of the catalyst and is also known to be autocatalytic . Factors affecting catalyst selection include balancing three reactions: urethane (polyol+isocyanate, or gel) formation, the urea (water+isocyanate, or "blow") formation, or the isocyanate trimerization reaction (e.g., using potassium acetate, to form isocyanurate rings). A variety of specialized catalysts have been developed. Surfactants are used to modify

492-584: A day-sack. In 1997, the Defence Clothing and Textile Agency had decided that the issue of 1990 pattern (infantry)-type PLCE to individual soldiers was to be scaled as follows: The standard-issue accoutrement today, dependent upon the branch of service, was changed to the capacity of two front pouches (pouch, ammunition, universal, DPM, IRR) instead of one. To this, privately purchased water bottle or utility pouches and hip pads are often added. The entrenching tool pouch (carrier, entrenching tool case, DPM, IRR)

574-491: A dividing strip to hold two magazines in separate compartments and eliminate rattle. Some soldiers, especially infantry soldiers, often removed these dividing strips to make it easier to insert and remove magazines. They also found that three magazines would then fit comfortably and without excessive noise, giving a total capacity of twelve magazines per person in a standard fighting configuration. Later issue ammunition pouches were manufactured without dividers, as eight magazines

656-431: A full suite of statistical process control software. Add-ons to dispense equipment include nucleation or gas injection units, and third or fourth stream capability for adding pigments or metering in supplemental additive packages. Distinct from pour-in-place, bun and boardstock, and coating applications, the production of piece parts requires tooling to contain and form the reacting liquid. The choice of mold-making material

738-403: A high molecular weight polyether backbone. They are used to increase the load-bearing properties of low-density high-resiliency (HR) foam, as well as add toughness to microcellular foams and cast elastomers. Initiators such as ethylenediamine and triethanolamine are used to make low molecular weight rigid foam polyols that have built-in catalytic activity due to the presence of nitrogen atoms in

820-420: A high percentage of fluorine–carbon bonds, which are the strongest bonds among all chemical bonds, fluorinated polyurethanes exhibit resistance to UV, acids, alkali, salts, chemicals, solvents, weathering, corrosion, fungi and microbial attack. These have been used for high performance coatings and paints. Phosphorus -containing polyols are available that become chemically bonded to the polyurethane matrix for

902-1479: A mix head, and a control unit. Often, a conditioning or heater–chiller unit is added to control material temperature in order to improve mix efficiency, cure rate, and to reduce process variability. Choice of dispense equipment components depends on shot size, throughput, material characteristics such as viscosity and filler content, and process control . Material day tanks may be single to hundreds of gallons in size and may be supplied directly from drums, IBCs ( intermediate bulk containers , such as caged IBC totes ), or bulk storage tanks . They may incorporate level sensors, conditioning jackets, and mixers. Pumps can be sized to meter in single grams per second up to hundreds of pounds per minute. They can be rotary, gear, or piston pumps, or can be specially hardened lance pumps to meter liquids containing highly abrasive fillers such as chopped or hammer-milled glass fiber and wollastonite . The pumps can drive low-pressure (10 to 30 bar, 1 to 3 MPa) or high-pressure (125 to 250 bar, 12.5 to 25.0 MPa) dispense systems. Mix heads can be simple static mix tubes, rotary-element mixers, low-pressure dynamic mixers, or high-pressure hydraulically actuated direct impingement mixers . Control units may have basic on/off and dispense/stop switches, and analogue pressure and temperature gauges, or may be computer-controlled with flow meters to electronically calibrate mix ratio, digital temperature and level sensors, and

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984-588: A mold. The addition of fillers, such as milled glass, mica , and processed mineral fibers, gave rise to reinforced RIM (RRIM), which provided improvements in flexural modulus (stiffness), reduction in coefficient of thermal expansion and better thermal stability. This technology was used to make the first plastic-body automobile in the United States, the Pontiac Fiero , in 1983. Further increases in stiffness were obtained by incorporating pre-placed glass mats into

1066-442: A more comfortable carry, than provided with the use of a four-point shoulder harness. Pouches that are to be worn on the back (field pack, utility, water bottle, respirator, wire cutter, entrenching tool) attach to the belt using the same loop and tab system. The detachable side pouches of a Bergen ( pouch, side, rucksack, DPM, IRR ) can be attached to the dedicated shoulder harness ( yoke, pouch side, rucksack, DPM, IRR ) to construct

1148-423: A polymer that is very stretchy, short chains with many crosslinks produce a hard polymer while long chains and intermediate crosslinking give a polymer useful for making foam. The choices available for the isocyanates and polyols, in addition to other additives and processing conditions allow polyurethanes to have the very wide range of properties that make them such widely used polymers. The main ingredients to make

1230-1079: A polyurethane are di- and tri- isocyanates and polyols . Other materials are added to aid processing the polymer or to modify the properties of the polymer. PU foam formulation sometimes have water added too. Isocyanates used to make polyurethane have two or more isocyanate groups on each molecule. The most commonly used isocyanates are the aromatic diisocyanates, toluene diisocyanate (TDI) and methylene diphenyl diisocyanate , (MDI). These aromatic isocyanates are more reactive than aliphatic isocyanates. TDI and MDI are generally less expensive and more reactive than other isocyanates. Industrial grade TDI and MDI are mixtures of isomers and MDI often contains polymeric materials. They are used to make flexible foam (for example slabstock foam for mattresses or molded foams for car seats), rigid foam (for example insulating foam in refrigerators) elastomers (shoe soles, for example), and so on. The isocyanates may be modified by partially reacting them with polyols or introducing some other materials to reduce volatility (and hence toxicity) of

1312-591: A polyurethane system, or simply a system. The isocyanate is commonly referred to in North America as the 'A-side' or just the 'iso'. The blend of polyols and other additives is commonly referred to as the 'B-side' or as the 'poly'. This mixture might also be called a 'resin' or 'resin blend'. In Europe the meanings for 'A-side' and 'B-side' are reversed. Resin blend additives may include chain extenders, cross linkers , surfactants , flame retardants , blowing agents , pigments , and fillers . Polyurethane can be made in

1394-419: A small utility pouch and again a zippered pocket with notepad holder. All pouches open and close with ITW Nexus clips as well as having storm seals. The vest is adjusted through four ladderlock fasteners and webbing, the shoulders are adjustable with Velcro material. The concept is to gain a secure load carrying system that fits over body armour comfortably. There are various types of this vest depending upon

1476-527: A solid colour dependent on its reflectance and the camouflage pattern would be lost. The Infantry Trials and Development Unit (ITDU), based in Warminster , conducted trials with the PLCE webbing system. It had decided for the system to be fit for purpose, and divided the system into three orders of dress: The Assault Order consists of the essentials needed to conduct a military task in the theatre of war. Ammunition,

1558-410: A sorbitol/water solution ( f  = 2.75). Polyols for rigid applications use higher functionality initiators such as sucrose ( f  = 8), sorbitol ( f  = 6), toluenediamine ( f  = 4), and Mannich bases ( f  = 4). Propylene oxide and/or ethylene oxide is added to the initiators until the desired molecular weight is achieved. The order of addition and

1640-541: A suitable polyol precursor. Polyester polyols are made by the polycondensation of multifunctional carboxylic acids and polyhydroxyl compounds. They can be further classified according to their end use. Higher molecular weight polyols (molecular weights from 2,000 to 10,000) are used to make more flexible polyurethanes while lower molecular weight polyols make more rigid products. Polyols for flexible applications use low functionality initiators such as dipropylene glycol ( f  = 2), glycerine ( f  = 3), or

1722-590: A variety of densities and hardnesses by varying the isocyanate, polyol or additives. Fully reacted polyurethane polymer is chemically inert . No exposure limits have been established in the U.S. by OSHA ( Occupational Safety and Health Administration ) or ACGIH ( American Conference of Governmental Industrial Hygienists ). It is not regulated by OSHA for carcinogenicity. Polyurethanes are combustible. Decomposition from fire can produce significant amounts of carbon monoxide and hydrogen cyanide , in addition to nitrogen oxides, isocyanates, and other toxic products. Due to

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1804-705: Is available in either the Disruptive Pattern Material ( DPM ) camouflage pattern, or the Desert DPM (''DDPM'') camouflage pattern. Commercial variants are available in multiple colours, such as Black, Green, or the American Desert Camouflage Uniform ( DCU ) camouflage pattern. The main criticism of the PLCE webbing system amongst members of the British Armed Forces is that the belt is prone to slipping. Some soldiers opt to change

1886-531: Is dependent on the expected number of uses to end-of-life (EOL), molding pressure, flexibility, and heat transfer characteristics. RTV silicone is used for tooling that has an EOL in the thousands of parts. It is typically used for molding rigid foam parts, where the ability to stretch and peel the mold around undercuts is needed. The heat transfer characteristic of RTV silicone tooling is poor. High-performance, flexible polyurethane elastomers are also used in this way. Epoxy, metal-filled epoxy, and metal-coated epoxy

1968-434: Is especially the case if the yellowing happens on the outer portions of a large foam, as the deterioration of properties in the outer portion has little effect on the overall bulk properties of the foam itself. It has been reported that exposure to visible light can affect the variability of some physical property test results. Higher-energy UV radiation promotes chemical reactions in foam, some of which are detrimental to

2050-427: Is excellent. Finally, molded or milled polypropylene is used to create low-volume tooling for molded gasket applications. Instead of many expensive metal molds, low-cost plastic tooling can be formed from a single metal master, which also allows greater design flexibility. The heat transfer characteristic of polypropylene tooling is poor, which must be taken into consideration during the formulation process. In 2007,

2132-469: Is of particular interest in the area of polyurethane coatings, where light stability is a critical factor and is the main reason that aliphatic isocyanates are used in making polyurethane coatings. When PU foam, which is made using aromatic isocyanates, is exposed to visible light, it discolors, turning from off-white to yellow to reddish brown. It has been generally accepted that apart from yellowing, visible light has little effect on foam properties. This

2214-520: Is produced from double-layered 1,000 Denier internally rubberised Cordura Nylon , a long lasting and hard wearing fabric. Olive webbing of the same material ("1000 D") is being incorporated, along with a variety of hard wearing plastic fasteners (ITW Nexus) , Hook and loop fasteners ( Velcro ) and anti-magnetic press stud fasteners ("pull the dot"). The pouches are opened and closed with Spanish tab fasteners, they can be closed in two ways, quick release or secure. Small sections of Velcro , sewn on

2296-593: Is sometimes made using small amounts of blowing agents to give less dense foam, better cushioning/energy absorption or thermal insulation. In the early 1990s, because of their impact on ozone depletion , the Montreal Protocol restricted the use of many chlorine -containing blowing agents, such as trichlorofluoromethane (CFC-11). By the late 1990s, blowing agents such as carbon dioxide , pentane , 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) were widely used in North America and

2378-603: Is sometimes used as an alternative water bottle pouch. Multi Terrain Pattern (MTP) PLCE is replacing all Disruptive Pattern Material (DPM) PLCE as the core issued webbing equipment for the British Armed Forces, this program started in 2015. The following example of individual components, are all current issue items of the British Armed Forces , however many commercial variants are available. A new standard-issue piece of equipment ( Waistcoat, Mans, General Purpose Ops. ) that

2460-840: Is typically produced by reacting a polymeric isocyanate with a polyol . Since a polyurethane contains two types of monomers, which polymerize one after the other, they are classed as alternating copolymers . Both the isocyanates and polyols used to make a polyurethane contain two or more functional groups per molecule. Global production in 2019 was 25 million metric tonnes, accounting for about 6% of all polymers produced in that year. Otto Bayer and his coworkers at IG Farben in Leverkusen, Germany, first made polyurethanes in 1937. The new polymers had some advantages over existing plastics that were made by polymerizing olefins or by polycondensation , and were not covered by patents obtained by Wallace Carothers on polyesters . Early work focused on

2542-405: Is used for tooling that has an EOL in the tens of thousands of parts. It is typically used for molding flexible foam cushions and seating, integral skin and microcellular foam padding, and shallow-draft RIM bezels and fascia. The heat transfer characteristic of epoxy tooling is fair; the heat transfer characteristic of metal-filled and metal-coated epoxy is good. Copper tubing can be incorporated into

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2624-597: The 58 pattern webbing , which was olive drab/olive green (OD/OG) in colour and made of canvas . This system, after having been introduced to the forces in 1960 and considered long obsolete by 1980, was still part of the standard-issue equipment of the British Armed Forces during the Falklands War in 1982. To address the common issues with canvas materials, such as shrinking and accelerated degradation in damp climates, arctic conditions, or prolonged exposure to wet terrain, military load-bearing systems—beyond those used by

2706-458: The British Armed Forces . Dependent upon the year of design, and the decade of introduction, the webbing system was named and is commonly referred to as the 85 Pattern , the 90 Pattern or the 95 Pattern webbing. The basic configuration consists of a belt, a shoulder harness and a number of pouches. Associated with the PLCE webbing system is a series of other similar load carrying equipment, individual items and rucksacks that are produced of

2788-821: The German Democratic Republic designed and introduced the Uniformtrageversuch 85–90 (UTV 85–90), resembling, with the exception of the clothing system, a modified duplicate of the British Type 58 Pattern webbing , inheriting very similar features in appearance and function. The shoulder harness was of identical design, the belt had featured the use of identical buckles and 58 Pattern C-hooks had been incorporated in all components. Complementary items, such as pouches, had been changed in design and size, to meet Warsaw Pact requirements. The webbing system and components were produced of more robust Nylon and featured

2870-473: The SA80 family of British small arms. Trials of experimental PLCE webbing and combat body armour (CBA) were conducted with selected units in 1984 and 1985. Being very similar to the first standard issue PLCE webbing system, it used snaps of proprietary design for closure on all pouches . Seven years after the Falklands War , the first standard issue PLCE webbing was introduced in 1989 as the 90 pattern webbing and

2952-553: The Strichtarn camouflage pattern. Whilst this late improvement was observed by the British Armed Forces and being found to be an affront, especially against the British Army of the Rhine (BAOR), no further considerations have been made, as the testing of prototypic PLCE equipment was already underway. Developments resumed with the progression of the firearms development and introduction of

3034-603: The modular lightweight load-carrying equipment (MOLLE) which is being widely employed by most branches of the United States Armed Forces . Following this major improvement, the Pouch Attachment Ladder System (PALS) had been incorporated into the Osprey Body Armour (OBA) platform, which is currently being issued to British troops on operations world-wide. Polyurethane A polyurethane

3116-478: The 1960s, automotive interior safety components, such as instrument and door panels, were produced by back-filling thermoplastic skins with semi-rigid foam. In 1969, Bayer exhibited an all-plastic car in Düsseldorf , Germany. Parts of this car, such as the fascia and body panels, were manufactured using a new process called reaction injection molding (RIM), in which the reactants were mixed and then injected into

3198-606: The 90 Pattern. Due to confusion, or for the sake of convenience, individual components of the webbing system, were by 1995, unofficially named, described and specified as the Type 95 pattern webbing, as having been widely understood to be part of the Combat Soldier 95 clothing system. No official name change had taken place. The only array of PLCE components that could be considered of the unofficial 95 pattern, are those components produced during or after that year. The PLCE webbing system

3280-720: The 90 pattern incorporates ambidextrous yoke fittings and the standard PLCE webbing belt attachments (see below). The PLCE webbing system was also adopted by the Danish Defence Forces ( Forsvaret ) in the M84 camouflage pattern and by the Defence Forces of Ireland ( Óglaigh na hÉireann ) in olive drab. The permanent and reserve defence forces now employ the integrated protection and load-carrying system (IPLCS). Many other countries still issue or have issued similar load bearing systems. By way of example, in its year of introduction to

3362-686: The British Armed Forces—have been redesigned to include or be made from newer and more durable synthetic materials. During the Vietnam War , the United States Armed Forces had introduced and serviced the M-1967 modernized load-carrying equipment (MLCE) in 1968 and later the all-purpose lightweight individual carrying equipment (ALICE) in 1974. Both systems had incorporated non-decomposing synthetic fabrics and were produced of highly durable nylon . Following this influential lead and reconsidering

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3444-544: The British soldier to live and fight for a period of 24 hours. The second side pouch of the rucksack is now carried. In practice, the patrol packs are used by many units and individual soldiers instead of the side pouches, as they are to be found larger in size and more convenient. The Marching Order is the Combat Order in addition to the carrying of the rucksack ( Bergen ) and is the fighting load required for operations of up to

3526-610: The EU, although chlorinated blowing agents remained in use in many developing countries. Later, HFC-134a was also banned due to high ODP and GWP readings, and HFC-141B was introduced in early 2000s as an alternate blowing agent in developing nations. Polyurethanes are produced by reacting di isocyanates with polyols , often in the presence of a catalyst , or upon exposure to ultraviolet radiation. Common catalysts include tertiary amines , such as DABCO , DMDEE , or metallic soaps , such as dibutyltin dilaurate . The stoichiometry of

3608-520: The Environment). In Europe, health and safety information is available from ISOPA, the European Diisocyanate and Polyol Producers Association. The methods of manufacturing polyurethane finished goods range from small, hand pour piece-part operations to large, high-volume bunstock and boardstock production lines. Regardless of the end-product, the manufacturing principle is the same: to meter

3690-463: The RIM mold cavity, also known broadly as resin injection molding , or structural RIM. Starting in the early 1980s, water-blown microcellular flexible foams were used to mold gaskets for automotive panels and air-filter seals, replacing PVC polymers. Polyurethane foams are used in many automotive applications including seating, head and arm rests, and headliners. Polyurethane foam (including foam rubber)

3772-640: The United States, additional health and safety information can be found through organizations such as the Polyurethane Manufacturers Association (PMA) and the Center for the Polyurethanes Industry (CPI), as well as from polyurethane system and raw material manufacturers. Regulatory information can be found in the Code of Federal Regulations Title 21 (Food and Drugs) and Title 40 (Protection of

3854-471: The addition of blowing agents by mechanically frothing the polyol prior to use. These are tough elastomeric materials used in covering car steering wheels or shoe soles . The properties of a polyurethane are greatly influenced by the types of isocyanates and polyols used to make it. Long, flexible segments, contributed by the polyol, give soft, elastic polymer. High amounts of crosslinking give tough or rigid polymers. Long chains and low crosslinking give

3936-588: The amounts of each oxide affect many polyol properties, such as compatibility, water-solubility, and reactivity. Polyols made with only propylene oxide are terminated with secondary hydroxyl groups and are less reactive than polyols capped with ethylene oxide, which contain primary hydroxyl groups. Incorporating carbon dioxide into the polyol structure is being researched by multiple companies. Graft polyols (also called filled polyols or polymer polyols) contain finely dispersed styrene–acrylonitrile , acrylonitrile , or polyurea (PHD) polymer solids chemically grafted to

4018-1867: The backbone. A special class of polyether polyols, poly(tetramethylene ether) glycols , which are made by polymerizing tetrahydrofuran , are used in high performance coating, wetting and elastomer applications. Conventional polyester polyols are based on virgin raw materials and are manufactured by the direct polyesterification of high-purity diacids and glycols, such as adipic acid and 1,4-butanediol. Polyester polyols are usually more expensive and more viscous than polyether polyols, but they make polyurethanes with better solvent, abrasion, and cut resistance. Other polyester polyols are based on reclaimed raw materials. They are manufactured by transesterification ( glycolysis ) of recycled poly(ethyleneterephthalate) (PET) or dimethylterephthalate (DMT) distillation bottoms with glycols such as diethylene glycol. These low molecular weight, aromatic polyester polyols are used in rigid foam, and bring low cost and excellent flammability characteristics to polyisocyanurate (PIR) boardstock and polyurethane spray foam insulation. Specialty polyols include polycarbonate polyols, polycaprolactone polyols, polybutadiene polyols, and polysulfide polyols. The materials are used in elastomer, sealant, and adhesive applications that require superior weatherability, and resistance to chemical and environmental attack. Natural oil polyols derived from castor oil and other vegetable oils are used to make elastomers, flexible bunstock, and flexible molded foam. Co-polymerizing chlorotrifluoroethylene or tetrafluoroethylene with vinyl ethers containing hydroxyalkyl vinyl ether produces fluorinated (FEVE) polyols. Two-component fluorinated polyurethanes prepared by reacting FEVE fluorinated polyols with polyisocyanate have been used to make ambient cure paints and coatings. Since fluorinated polyurethanes contain

4100-410: The belt; these have belt loops and feature T-Bar plastic tab attachments to provide more stability and security when connected to the belt. Every major component of the PLCE webbing system features two T-Bar plastic tab attachments. The six-point shoulder harness attaches to the two D-rings on the belt and the two A-rings on each front pouch chosen. This benefits the distribution of weight and allows for

4182-451: The body of the tool, allowing hot water to circulate and heat the mold surface. Aluminum is used for tooling that has an EOL in the hundreds of thousands of parts. It is typically used for molding microcellular foam gasketing and cast elastomer parts, and is milled or extruded into shape. Mirror-finish stainless steel is used for tooling that imparts a glossy appearance to the finished part. The heat transfer characteristic of metal tooling

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4264-788: The characteristics of both foam and non-foam polyurethane polymers. They take the form of polydimethylsiloxane-polyoxyalkylene block copolymers, silicone oils, nonylphenol ethoxylates, and other organic compounds. In foams, they are used to emulsify the liquid components, regulate cell size, and stabilize the cell structure to prevent collapse and sub-surface voids. In non-foam applications they are used as air release and antifoaming agents, as wetting agents, and are used to eliminate surface defects such as pin holes, orange peel, and sink marks. Polyurethanes are produced by mixing two or more liquid streams. The polyol stream contains catalysts, surfactants, blowing agents (when making polyurethane foam insulation) and so on. The two components are referred to as

4346-416: The duration of two weeks, without means of resupply, except for ammunition, rations and water. The complete Bergen (with side pouches attached) is being carried. The initial basis of the PLCE webbing system is the belt; it features two D-rings at the back to attach to the shoulder harness, and many rows of narrow vertical slots sewn into the fabric. Two or more front pouches (ammunition or utility) attach to

4428-500: The exception of ethylene glycol, since its derived bis-phenyl urethane undergoes unfavorable degradation at high hard segment levels. Diethanolamine and triethanolamine are used in flex molded foams to build firmness and add catalytic activity. Diethyltoluenediamine is used extensively in RIM, and in polyurethane and polyurea elastomer formulations. Polyurethane catalysts can be classified into two broad categories, basic and acidic amine . Tertiary amine catalysts function by enhancing

4510-522: The flammability of the material, it has to be treated with flame retardants (at least in case of furniture), almost all of which are considered harmful. California later issued Technical Bulletin 117 2013 which allowed most polyurethane foam to pass flammability tests without the use of flame retardants. Green Science Policy Institute states: "Although the new standard can be met without flame retardants, it does NOT ban their use. Consumers who wish to reduce household exposure to flame retardants can look for

4592-424: The foam structure. Polyurethanes may degrade due to hydrolysis . This is a common problem with shoes left in a closet, and reacting with moisture in the air. Microbial degradation of polyurethane is believed to be due to the action of esterase , urethanase , hydrolase and protease enzymes. The process is slow as most microbes have difficulty moving beyond the surface of the polymer. Susceptibility to fungi

4674-402: The forces, the United States Armed Forces have adopted the individual integrated fighting system (IIFS). The newest variant of the PLCE webbing system, of the 90 pattern, has been in production since 1992 and has the Disruptive Pattern Material (DPM) camouflage pattern of the partially obsolete Combat Soldier 95 ("Soldier 95") clothing system. The official name remained unchanged. With

4756-479: The global consumption of polyurethane raw materials was above 12 million metric tons, and the average annual growth rate was about 5%. Revenues generated with PUR on the global market are expected to rise to approximately US$ 75 billion by 2022. As they are such an important class of materials, research is constantly taking place and papers published. Polyurethanes, especially those made using aromatic isocyanates, contain chromophores that interact with light. This

4838-621: The hard segments and consequent powerful hydrogen bonding contributes to high tensile strength, elongation, and tear resistance values. The choice of chain extender also determines flexural, heat, and chemical resistance properties. The most important chain extenders are ethylene glycol , 1,4-butanediol (1,4-BDO or BDO), 1,6-hexanediol , cyclohexane dimethanol and hydroquinone bis(2-hydroxyethyl) ether (HQEE). All of these glycols form polyurethanes that phase separate well and form well defined hard segment domains, and are melt processable. They are all suitable for thermoplastic polyurethanes with

4920-424: The hard segments, which are formed from the isocyanate and chain extenders, are stiff and immobile. As the hard segments are covalently coupled to the soft segments, they inhibit plastic flow of the polymer chains, thus creating elastomeric resiliency. Upon mechanical deformation, a portion of the soft segments are stressed by uncoiling, and the hard segments become aligned in the stress direction. This reorientation of

5002-477: The inside of the lids of the pouches and the top front section of the pouches, allow for easy and effortless fastening. Added silencer strips allow them to be covered when not needed. A standard ammunition pouch as issued ("pouch, ammunition, universal, DPM, IRR") has two pockets; single pocket versions ("pouch, ammunition (other arms), DPM, IRR") are available for those not required to carry as much ammunition. Pouches designated to hold ammunition initially contained

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5084-440: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=PLCE&oldid=1236343292 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Personal load carrying equipment Personal load carrying equipment ( PLCE ) is one of several tactical webbing systems of

5166-460: The introduction of the Combat Soldier 95 (CS95 or "Soldier 95") clothing system in 1995, the common misconception arose that a complete revision of the 90 Pattern PLCE webbing system was taking place. The clothing system underwent final development and entered troop trials in between 1992 and 1995. Garments were manufactured for the trials, yet the PLCE webbing system issued, officially remained of

5248-953: The isocyanates, decrease their freezing points to make handling easier or to improve the properties of the final polymers. Aliphatic and cycloaliphatic isocyanates are used in smaller quantities, most often in coatings and other applications where color and transparency are important since polyurethanes made with aromatic isocyanates tend to darken on exposure to light. The most important aliphatic and cycloaliphatic isocyanates are 1,6-hexamethylene diisocyanate (HDI), 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane ( isophorone diisocyanate , IPDI), and 4,4′-diisocyanato dicyclohexylmethane (H 12 MDI or hydrogenated MDI). Other more specialized isocyanates include Tetramethylxylylene diisocyanate (TMXDI). Polyols are polymers in their own right and have on average two or more hydroxyl groups per molecule. They can be converted to polyether polyols by co-polymerizing ethylene oxide and propylene oxide with

5330-506: The liquid isocyanate and resin blend at a specified stoichiometric ratio, mix them together until a homogeneous blend is obtained, dispense the reacting liquid into a mold or on to a surface, wait until it cures, then demold the finished part. Although the capital outlay can be high, it is desirable to use a meter-mix or dispense unit for even low-volume production operations that require a steady output of finished parts. Dispense equipment consists of material holding (day) tanks, metering pumps,

5412-429: The nucleophilicity of the diol component. Alkyl tin carboxylates, oxides and mercaptides oxides function as mild Lewis acids in accelerating the formation of polyurethane. As bases, traditional amine catalysts include triethylenediamine (TEDA, also called DABCO , 1,4-diazabicyclo[2.2.2]octane), dimethylcyclohexylamine (DMCHA), dimethylethanolamine (DMEA), Dimethylaminoethoxyethanol and bis-(2-dimethylaminoethyl)ether,

5494-451: The original bubbles or cells remain intact, or "open-cell", where the bubbles have broken but the edges of the bubbles are stiff enough to retain their shape, in extreme cases reticulated foams can be formed. Open-cell foams feel soft and allow air to flow through, so they are comfortable when used in seat cushions or mattresses . Closed-cell foams are used as rigid thermal insulation . High-density microcellular foams can be formed without

5576-490: The phase separation of the hard and soft copolymer segments of the polymer, such that the urethane hard segment domains serve as cross-links between the amorphous polyether (or polyester) soft segment domains. This phase separation occurs because the mainly nonpolar, low melting soft segments are incompatible with the polar, high melting hard segments. The soft segments, which are formed from high molecular weight polyols, are mobile and are normally present in coiled formation, while

5658-480: The plastic buckle for a Roll-Pin type, whereby the belt is threaded and tightened each time it is put on. In 2015, VIRTUS, the Personal Protective Equipment and Load Carriage System, began being issued to high readiness units. Due to the introduction and constant improvement of protective equipment, such as the Osprey Body Armour ( OBA ) , the PLCE webbing system is incompatible so Osprey Mk 4 has

5740-415: The presence of a gas, or blowing agent , during the polymerization step. This is commonly achieved by adding small amounts of water, which reacts with isocyanates to form CO 2 gas and an amine , via an unstable carbamic acid group. The amine produced can also react with isocyanates to form urea groups, and as such the polymer will contain both these and urethane linkers. The urea is not very soluble in

5822-778: The production of fibers and flexible foams and PUs were applied on a limited scale as aircraft coating during World War II . Polyisocyanates became commercially available in 1952, and production of flexible polyurethane foam began in 1954 by combining toluene diisocyanate (TDI) and polyester polyols. These materials were also used to produce rigid foams, gum rubber, and elastomers . Linear fibers were produced from hexamethylene diisocyanate (HDI) and 1,4-Butanediol (BDO). DuPont introduced polyethers, specifically poly(tetramethylene ether) glycol , in 1956. BASF and Dow Chemical introduced polyalkylene glycols in 1957. Polyether polyols were cheaper, easier to handle and more water-resistant than polyester polyols. Union Carbide and Mobay ,

5904-422: The progression and renewal of military load bearing systems around the world, Britain developed 72 pattern webbing , which mainly consisted of two ammunition pouches, to be worn on the front and a field pack, to be worn on the back, made of Polyurethane -coated nylon and Butyl rubber . This system was never generally issued but was a Troop Trials Equipment. The National People's Army ( Nationale Volksarmee ) of

5986-451: The reaction between polyamines and cyclic carbonates to produce polyhydroxyurethanes . Chain extenders ( f  = 2) and cross linkers ( f  ≥ 3) are low molecular weight hydroxyl and amine terminated compounds that play an important role in the polymer morphology of polyurethane fibers, elastomers, adhesives, and certain integral skin and microcellular foams. The elastomeric properties of these materials are derived from

6068-468: The reaction mixture and tends to form separate "hard segment" phases consisting mostly of polyurea . The concentration and organization of these polyurea phases can have a significant impact on the properties of the foam. The type of foam produced can be controlled by regulating the amount of blowing agent and also by the addition of various surfactants which change the rheology of the polymerising mixture. Foams can be either "closed-cell", where most of

6150-611: The same materials and which are compatible. The purpose of the PLCE webbing system is to retain the means by which a soldier may operate for 48 hours or conduct a mission-specific task. Items and components may include a variety of munitions and weapon ancillaries, a three-fold entrenching tool , a bayonet , food and water (including a means to heat water and prepare food), chemical, biological, radiological, and nuclear (CBRN) protective clothing and communications equipment. Soldiers often carry other personal items such as waterproof clothing and spare socks. The PLCE webbing system replaced

6232-430: The starting materials must be carefully controlled as excess isocyanate can trimerise , leading to the formation of rigid polyisocyanurates . The polymer usually has a highly crosslinked molecular structure, resulting in a thermosetting material which does not melt on heating; although some thermoplastic polyurethanes are also produced. The most common application of polyurethane is as solid foams , which requires

6314-623: The use as flame retardants . This covalent linkage prevents migration and leaching of the organophosphorus compound . Interest in sustainable "green" products raised interest in polyols derived from vegetable oils . Various oils used in the preparation polyols for polyurethanes include soybean oil , cottonseed oil , neem seed oil , and castor oil . Vegetable oils are functionalized in various ways and modified to polyetheramides , polyethers , alkyds , etc. Renewable sources used to prepare polyols may be fatty acids or dimer fatty acids . Some biobased and isocyanate-free polyurethanes exploit

6396-456: The water bottle, the entrenching tool, the bayonet, the helmet, and CBRN (chemical, biological, radiological, and nuclear) protective clothing (stowed in one of the detachable side pouches of the rucksack) is to be carried on operations and patrols of only short duration. The Combat Order is the Assault Order in addition to the means of stowage for rations and personal equipment, that enable

6478-505: The year of manufacture. The originals are as described above but newer models have loops on the left side for the bayonet frog, clips for a large hydration pouch, name patches on the left side, and a small utility pouch. Most recently, the Spanish tab fasteners are being incorporated again, instead of the ITW Nexus clips. The standard-issue assault vest, depending on the operational requirements,

6560-447: Was olive (OD/OG) in colour. The original components used Type 58 pattern C-hooks for the belt attachment, and angled D-rings for the shoulder harness attachment on the ammunition pouches. There were separate left and right pouches. The first utility pouches in production had additional belt attachments for high mounting, similar to the ammunition pouches of the 1937 pattern web equipment or 44 pattern . Later produced PLCE webbing of

6642-438: Was designed for carrying essential items on a more secure platform than the original webbing system. This consists of a typical waistcoat design, fastened with three ITW Nexus clips. Two triple ammunition pouches are situated on the left hand side of the coat, along with a utility pouch, small utility pouch and a zippered pocket with an internal holster. The right side is similar but with three large utility pouches, along with

6724-643: Was not thought to be sufficient for sustained firefights. Without dividers, each pouch can alternatively contain one grenade. Infrared reflective (IRR) coating and dyes are incorporated in all fabric and webbing of the PLCE webbing system, which replicates the near-infrared reflectance of natural foliage. For example, green foliage is highly reflective to near-infrared light and thus appears white when viewed through IR optics (or bright green through night vision). The IRR camouflage pattern therefore works correctly when viewed through infrared night vision optics just as it does in visible light. Non-IRR fabric would appear as

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