Patent Application
20140290473
The present invention relates in general to blast and ballistic protection and more specifically to a polycarbonate laminate useful for protection against close-proximity blast, ballistic and severe storm events.
Ahmad, in U.S. Pat. No. 7,562,613, provides a protective structure for protecting buildings, bridges, roads and other areas from explosive devices such as car bombs and the like made of: (a) a mesh structure having an outer surface and an inner surface, wherein the inner surface defines an annular space; (b) a plurality of structural steel cables in contact with the mesh structure; (c) composite fill material which resides within the annular space of the mesh structure and within the mesh structure; (d) at least one reinforcement member which resides within the composite fill material; and (e) a composite face material which resides upon the outer surface of the mesh structure. The mesh structure may be made up of, for example, steel wire. The described protective system for protecting buildings, bridges, roads and other areas from explosive devices such as car bombs etc. may be made from a plurality of the described protective structures and a plurality of support members, wherein the support members provide interlocking engagement of the protective structures to the support members.
U.S. Pat. No. 8,011,146, issued to Krause describes a blast-proof window and mullion system for sustaining and mitigating an explosion and/or blast to the window and mullion system on a multi-storied building or structure. The window and mullion system is detailed as including a blast-resistant mullion having a mullion housing with mullion walls with outer surfaces; and a pressure bar member having a pressure bar housing with an interior wall and a pair of outer walls being connected to the interior wall to form a center channel opening. The outer walls are said to be angled for reducing the space between the angled walls and for reducing the size of the center channel opening for reduction of bullet and/or blast penetration to the interior wall of the pressure bar member. Also, one of the mullion walls of the mullion housing is said to include a mullion tongue thereon having a pair of tongue extension arms for forming a vertical bolt receiving channel there between. Each of the tongue extension arms has interior serrated surfaces for receiving threaded bolts between the interior serrated surfaces. The interior wall of the pressure bar member has a pair of spaced-apart pressure bar extension arms thereon. The interior wall of the pressure bar member includes a plurality of spaced-apart bolt openings for receiving a plurality of the threaded bolts therein for permanently locking together the pressure bar extension arms with the mullion extension arms in order to join together and lock the pressure bar housing of the pressure bar member to said mullion housing of the blast-resistant mullion to form the blast-proof window and mullion system.
A need continues to exist in the art for improved protective systems for close-proximity blast, ballistic and severe storm events.
Accordingly, the present invention provides such improved protective systems for close-proximity blast, ballistic and severe storm events. The improved protective systems comprise a polycarbonate laminate that can protect an object against 50 lbs. to 100 lbs. of trinitrotoluene-equivalent from distances as close as about 3 feet (0.91 m). The improved polycarbonate laminate of the present invention comprises polycarbonate layers laminated with one or more thermoplastic polyurethane (“TPU”) interlayers to achieve a final laminate thickness in the range of about 4 inches (10.2 cm) to about 6 inches (15.2 cm). The inventive protective systems can be used either directly against a concrete wall (depending on construction) or optionally with an about 2 feet (0.61 m) to about 4 feet (1.22 m) air gap standoff from building. The inventive laminate and protective systems made with it can provide improved protection from close-proximity blast, ballistic events and severe storm events, such as hurricanes, cyclones, typhoons and tornados.
These and other advantages and benefits of the present invention will be apparent from the Detailed Description of the Invention herein below.
The present invention will now be described for purposes of illustration and not limitation in conjunction with the figures, wherein:
The present invention will now be described for purposes of illustration and not limitation. Except in the operating examples, or where otherwise indicated, all numbers expressing quantities, percentages, OH numbers, functionalities and so forth in the specification are to be understood as being modified in all instances by the term “about.” Equivalent weights and molecular weights given herein in Daltons (Da) are number average equivalent weights and number average molecular weights respectively, unless indicated otherwise.
The present invention provides a laminate for protecting an object against one of a close-proximity blast, a ballistic event and a severe storm event, the laminate comprising two or more layers of polycarbonate having layered therebetween one or more layers of a thermoplastic polyurethane.
The present invention further provides a protective system for one of a close-proximity blast, a ballistic event and a severe storm event, the system comprising a laminate comprising two or more layers of polycarbonate having layered therebetween one or more layers of a thermoplastic polyurethane.
The present invention yet further provides a method for protecting an object from one of a close-proximity blast, a ballistic event and a severe storm event, the method involving placing between the object and the blast, ballistic and storm event, a laminate comprising two or more layers of polycarbonate having layered therebetween one or more layers of a thermoplastic polyurethane.
The present invention still further provides a method of protecting an object against 50 lbs. (22.7 kg) to 100 lbs. (45.4 kg) of trinitrotoluene-equivalent detonated at a distance of about 3 feet (0.914 m), the method involving placing between the object and the 50 lbs. to 100 lbs. of trinitrotoluene-equivalent, a laminate comprising two or more layers of polycarbonate having layered there between one or more layers of a thermoplastic polyurethane.
Suitable polycarbonate resins for preparing the laminates of the present invention are homopolycarbonates and copolycarbonates, both linear or branched resins and mixtures thereof.
The polycarbonates have a weight average molecular weight of preferably 10,000 to 200,000, more preferably 20,000 to 80,000 and their melt flow rate, per ASTM D-1238 at 300° C., is preferably 1 to 65 g/10 min., more preferably 2 to 35 g/10 min. They may be prepared, for example, by the known diphasic interface process from a carbonic acid derivative such as phosgene and dihydroxy compounds by polycondensation (See, German Offenlegungssehriften 2,063,050; 2,063,052; 1,570,703; 2,211,956; 2,211,957 and 2,248,817; French Patent 1,561,518; and the monograph by H. Schnell, “Chemistry and Physics of Polycarbonates”, Interscience Publishers, New York, N.Y., 1964).
In the present context, dihydroxy compounds suitable for the preparation of the polycarbonates of the invention conform to the structural formulae (1) or (2) below.
wherein
Among the dihydroxy compounds useful in the practice of the invention are hydroquinone, resorcinol, bis-(hydroxyphenyl)-alkanes, bis-(7droxyl-phenyl)-ethers, bis-(hydroxyphenyl)-ketones, bis-(7ydroxyl-phenyl)-sulfoxides, bis-(hydroxyphenyl)-sulfides, bis-(hydroxyphenyl)-sulfones, and α,α-bis-(hydroxyphenyl)-diisopropylbenzenes, as well as their nuclear-alkylated compounds. These and further suitable aromatic dihydroxy compounds are described, for example, in U.S. Pat. Nos. 5,401,826, 5,105,004; 5,126,428; 5,109,076; 5,104,723; 5,086,157; 3,028,356; 2,999,835; 3,148,172; 2,991,273; 3,271,367; and 2,999,846, the contents of which are incorporated herein by reference.
Further examples of suitable bisphenols are 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 2,4-bis-(4-hydroxyphenyl)-2-methyl-butane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane, α,α′-bis-(4-hydroxy-phenyl)-p-diisopropylbenzene, 2,2-bis-(3-methyl-4-hydroxyphenyl)-propane, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, 4,4′-dihydroxy-diphenyl, bis-(3,5-dimethyl-4-hydroxyphenyl)-methane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfide, bis-(3,5-dimethyl-4-hydroxy-phenyl)-sulfoxide, bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfone, dihydroxy-benzophenone, 2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane, α,α′-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropyl-benzene and 4,4′-sulfonyl diphenol.
Examples of particularly preferred aromatic bisphenols are 2,2-bis-(4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane and 1,1-bis-(4-hydroxy-phenyl)-3,3,5-trimethylcyclohexane. The most preferred bisphenol is 2,2-bis(4-hydroxyphenyl)-propane (bisphenol A).
The polycarbonates useful in producing the sheets for the laminates of the invention may entail in their structure units derived from one or more of the suitable bisphenols.
Among the resins suitable in the practice of the invention are phenolphthalein-based polycarbonate, copolycarbonates and terpolycarbonates such as are described in U.S. Pat. Nos. 3,036,036 and 4,210,741, both of which are incorporated by reference herein.
The polycarbonates useful in preparing the sheets laminates of the invention may also be branched by condensing therein small quantities, e.g., 0.05 to 2.0 mol % (relative to the bisphenols) of polyhydroxyl compounds. Polycarbonates of this type have been described, for example, in German Offenlegungsschriften 1,570,533; 2,116,974 and 2,113,374; British Patents 885,442 and 1,079,821 and U.S. Pat. No, 3,544,514, which is incorporated herein by reference. The following are some examples of polyhydroxyl compounds which may be used for this purpose: phloroglucinol; 4,6-dimethyl-2,4,6-tri-(4-hydroxy-phenyl)-heptane; 1,3,5-tri-(4-hydroxyphenyl)-benzene; 1,1,1-tri-(4-hydroxyphenyl)-ethane; tri-(4-hydroxyphenyl)-phenyl-methane; 2,2-bis-[4,4-(4,4′-dihydroxydiphenyl)]-cyclohexyl-propane; 2,4-bis-(4-hydroxy-1-isopropylidine)-phenol; 2,6-bis-(2′-dihydroxy-5′-methylbenzyl)-4-methyl-phenol; 2,4-dihydroxybenzoic acid; 2-(4-hydroxy-phenyl)-2-(2,4-dihydroxy-phenyl)-propane and 1,4-bis-(4,4′-dihydroxytri-phenylmethyl)-benzene. Some of the other polyfunctional compounds are 2,4-dihydroxy-benzoic acid, trimesic acid, cyanuric chloride and 3,3-bis-(4-hydroxyphenyl)-2-oxo-2,3-dihydroindole.
In addition to the polycondensation process mentioned above, other processes for the preparation of the polycarbonates of the invention are polycondensation in a homogeneous phase and transesterification. The suitable processes are disclosed in U.S. Pat. Nos. 3,028,365; 2,999,846; 3,153,008; and 2,991,273 which are incorporated herein by reference.
The preferred process for the preparation of polycarbonates is the interfacial polycondensation process. Other methods of synthesis in forming the polycarbonates of the invention, such as disclosed in U.S. Pat. No. 3,912,688, incorporated herein by reference, may be used. Suitable polycarbonate materials are available in commerce, for instance, from Bayer MaterialScience under the MAKROLON and HYGARD trademarks. The polycarbonate is preferably used in the form of sheets or films in the inventive laminates.
Aliphatic thermoplastic polyurethanes are particularly preferred in the laminates of the present invention such as those prepared according to U.S. Pat. No. 6,518,389, the entire contents of which are incorporated herein by reference.
Thermoplastic polyurethane elastomers are well known to those skilled in the art. They are of commercial importance due to their combination of high-grade mechanical properties with the known advantages of cost-effective thermoplastic processability. A wide range of variation in their mechanical properties can be achieved by the use of different chemical synthesis components. A review of thermoplastic polyurethanes, their properties and applications is given in Kunststoffe [Plastics] 68 (1978), pages 819 to 825, and in Kautschuk, Gummi, Kunststoffe [Natural and Vulcanized Rubber and Plastics] 35 (1982), pages 568 to 584.
Thermoplastic polyurethanes are synthesized from linear polyols, mainly polyester diols or polyether diols, organic diisocyanates and short chain diols (chain extenders). Catalysts may be added to the reaction to speed up the reaction of the components.
The relative amounts of the components may be varied over a wide range of molar ratios in order to adjust the properties. Molar ratios of polyols to chain extenders from 1:1 to 1:12 have been reported. These result in products with hardness values ranging from 80 Shore A to 75 Shore D.
Thermoplastic polyurethanes can be produced either in stages (prepolymer method) or by the simultaneous reaction of all the components in one step (one shot). In the former, a prepolymer formed from the polyol and diisocyanate is first formed and then reacted with the chain extender. Thermoplastic polyurethanes may be produced continuously or batch-wise. The best-known industrial production processes are the so-called belt process and the extruder process.
Examples of the suitable polyols include difunctional polyether polyols, polyester polyols, and polycarbonate polyols. Small amounts of trifunctional polyols may be used, yet care must be taken to make certain that the thermoplasticity of the thermoplastic polyurethane remains substantially un-effected.
Suitable polyester polyols include those which are prepared by polymerizing ε-caprolactone using an initiator such as ethylene glycol, ethanolamine and the like. Further suitable examples are those prepared by esterification of polycarboxylic acids. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic and they may be substituted, e.g., by halogen atoms, and/or unsaturated. The following are mentioned as examples: succinic acid; adipic acid; suberic acid; azelaic acid; sebacic acid; phthalic acid; isophthalic acid; trimellitic acid; phthalic acid anhydride; tetrahydrophthalic acid anhydride; hexahydrophthalic acid anhydride; tetrachlorophthalic acid anhydride, endomethylene tetrahydrophthalic acid anhydride; glutaric acid anhydride; maleic acid; maleic acid anhydride; fumaric acid; dimeric and trimeric fatty acids such as oleic acid, which may be mixed with monomeric fatty acids; dimethyl terephthalates and bis-glycol terephthalate. Suitable polyhydric alcohols include, e.g., ethylene glycol; propylene glycol-(1,2) and -(1,3); butylene glycol-(1,4) and -(1,3); hexanediol-(1,6); octanediol-(1,8); neopentyl glycol; (1,4-bis-hydroxy-methylcyclohexane); 2-methyl-1,3-propanediol; 2,2,4-tri-methyl-1,3-pentanediol; triethylene glycol; tetraethylene glycol; polyethylene glycol; dipropylene glycol; polypropylene glycol; dibutylene glycol and polybutylene glycol, glycerine and trimethlyolpropane.
Suitable polyisocyanates for producing the thermoplastic polyurethanes useful in the laminates of the present invention may be, for example, organic aliphatic diisocyanates including, for example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate, 1-isocyanato-2-isocyanatomethyl cyclopentane, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (isophorone diisocyanate or IPDI), bis-(4-isocyanatocyclohexyl)-methane, 2,4′-dicyclohexylmethane diisocyanate, 1,3- and 1,4-bis-(isocyanatomethyl)-cyclohexane, bis-(4-isocyanato-3-methylcyclohexyl)-methane, α,α,α′,α′-tetramethyl-1,3- and/or -1,4-xylylene diisocyanate, 1-isocyanato-1-methyl-4(3)-isocyanatomethyl cyclohexane, 2,4- and/or 2,6-hexahydrotoluylene diisocyanate, and mixtures thereof.
Preferred chain extenders with molecular weights of 62 to 500 include aliphatic diols containing 2 to 14 carbon atoms, such as ethanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and 1,4-butanediol in particular, for example. However, diesters of terephthalic acid with glycols containing 2 to 4 carbon atoms are also suitable, such as terephthalic acid-bis-ethylene glycol or -1,4-butanediol for example, or hydroxyalkyl ethers of hydroquinone, such as 1,4-di-(β-hydroxyethyl)-hydroquinone for example, or (cyclo)aliphatic diamines, such as isophorone diamine, 1,2- and 1,3-propylenediamine, N-methyl-propylenediamine-1,3 or N,N′-dimethyl-ethylenediamine, for example, and aromatic diamines, such as toluene 2,4- and 2,6-diamines, 3,5-diethyltoluene 2,4- and/or 2,6-diamine, and primary ortho-, di-, tri- and/or tetraalkyl-substituted 4,4′-diaminodiphenylmethanes, for example. Mixtures of the aforementioned chain extenders may also be used. Optionally, triol chain extenders having a molecular weight of 62 to 500 may also be used. Moreover, customary monofunctional compounds may also be used in small amounts, e.g., as chain terminators or demolding agents. Alcohols such as octanol and stearyl alcohol or amines such as butylamine and stearylamine may be cited as examples.
To prepare the thermoplastic polyurethanes, the synthesis components may be reacted, optionally in the presence of catalysts, auxiliary agents and/or additives, in amounts such that the equivalent ratio of NCO groups to the sum of the groups which react with NCO, particularly the OH groups of the low molecular weight diols/triols and polyols, is 0.9:1.0 to 1.2:1.0, preferably 0.95:1.0 to 1.10:1.0.
Suitable catalysts include tertiary airlines which are known in the art, such as triethylamine, dimethyl-cyclohexylamine, N-methylmorpholine, N,N′-dimethyl-piperazine, 2-(dimethyl-aminoethoxy)-ethanol, diazabicyclo-(2,2,2)-octane and the like, for example, as well as organic metal compounds in particular, such as titanic acid esters, iron compounds, tin compounds, e.g., tin diacetate, tin dioctoate, tin dilaurate or the dialkyltin salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate or the like. The preferred catalysts are organic metal compounds, particularly titanic acid esters and iron and/or tin compounds.
In addition to difunctional chain extenders, small quantities of up to about 5 mol. Percent, based on moles of the bifunctional chain extender used, of trifunctional or more than trifunctional chain extenders may also be used.
Trifunctional or more than trifunctional chain extenders of the type in question are, for example, glycerol, trimethylolpropane, hexanetriol, pentaerythritol and triethanolamine.
Suitable thermoplastic polyurethanes are available in commerce, for example, from Bayer MaterialScience under the TEXIN trademark. The thermoplastic polyurethanes are preferably used in the present invention in the form of films or sheets.
The thickness of the laminate of the present invention is preferably 4 inches (10.2 cm) to 6 inches (15.2 cm), more preferably 4 inches (10.2 cm) to 5 inches (12.7 cm). The thickness of the laminate of the present invention may be in an amount ranging between any combination of these values, inclusive of the recited values. Optionally, the inventive laminate may be placed at a standoff of 2 feet (0.61 m) to 4 feet (1.22 m), more preferably 3 feet (0.91 m) to 4 feet (1.22 m) from the object (such as a building or other structure) to be protected to introduce an “air gap” between the laminate and the structure and thereby provide additional protection against the blast, ballistic or severe storm event. The standoff distance of the inventive laminate from the object to be protected may be in an amount ranging between any combination of these values, inclusive of the recited values. Although the laminate of the present invention is most often illustrated in the present disclosure as a three polycarbonate/two thermoplastic polyurethane material, those skilled in the art will recognize that any number and combination of layers is possible depending upon the level of protection desired.
The present invention is further illustrated, but is not to be limited, by the following examples. The following materials were used in modeling the illustrated blast protective systems:
A blast protective system is shown in
The results of these examples are summarized below in Table 1. As can be appreciated by reference to Table 1, the laminate is predicted to be effective against a 50 lbs. (22.7 kg) charge of trinitrotoluene-equivalent as close as 4 feet (1.22 m) before significant damage is seen in the concrete wall. Additional studies (data not reported here) have shown the laminate to be effective against 100 lbs. (45.4 kg) of trinitrotoluene-equivalent from 5 feet (1.52 m).
4964 (34.2)
The present inventors contemplate that the laminate of the present invention is well suited for providing protection from close-proximity blast, ballistic events and severe storm events, such as hurricanes, cyclones, typhoons and tornados.
The foregoing examples of the present invention are offered for the purpose of illustration and not limitation. It will be apparent to those skilled in the art that the embodiments described herein may be modified or revised in various ways without departing from the spirit and scope of the invention. The scope of the invention is to be measured by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 61499256 | Jun 2011 | US | national |
The present invention is a non-provisional application of provisional application 61/499,256 filed Jun. 21, 2011, the entirety of which is incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US12/43262 | 6/20/2012 | WO | 00 | 5/22/2014 |
