CN1723122A - Impact and Fire Resistant Composite Materials - Google Patents

Abstract

The present invention relates to impact and fire resistant composites for aircraft interiors and other uses. The provided composite has a flexural modulus of at least about 80,000 pounds per square inch (552MPa), a flexural yield strength of at least about 800 pounds per square inch (5.52MPa), from about 0.9 to about 1.5 pounds per square foot (4.40-5.86 kg/m)²) (iii) an areal density of at least about 1430 feet/second (427m/s) of V0, meeting U.S. Federal regulations No. 14 at 1/2002, fire resistance required by 25.853, and tested using a 9mm all metal shell round nose bullet (FMJRN) of 240 grain (15.6g) mass, and 124 grain (8.0g) mass, according to 2002, 1/10 Ri.America, Federal Aviation Administration (FAA) advisory notice 25.795.2.

Description

Impact and Fire Resistant Composite Materials

Background of the invention

1. Field of invention

This invention relates to impact and fire resistant composite materials, and more particularly, the invention relates to impact and fire resistant composite materials for aircraft interior components and other applications.

2. Description of related technologies

Materials used for components in the nacelle are regulated by 14 CFR Part 25. Until recently, the main concern when it comes to this material has been fire resistance. However, following the September 11, 2001 hijacking by suicide terrorists, protection against other types of threats has received heightened attention. Among the main concerns is the safety of the crew and the cabin against firearms. The materials used for the cabin doors were required to be lightweight, resistant to penetration by pistol bullets and also maintain current fire resistance standards.

Refractory materials for aircraft interiors are described in US Patents 4,780,359, 5,175,198, 5,714,419 and 5,972,512. US Patent 6,044,605 describes door construction "...may be made of fire and impact resistant materials...".

US Patent 3,934,066 describes a flame retardant multilayer system suitable for flammable and heat sensitive substrates comprising a flexible protective layer and an intumescent layer comprising a porous cellulose sheet impregnated with an intumescent composition. The flexible protective layer may be a metal foil.

Materials that possess both fire resistance and impact resistance are described in US Patents 4,822,439, 4,842,923, 4,929,651, 5,167,876, 5,215,813 and 5,480,706.

US Patents 4,822,439 and 4,929,651 describe composite materials comprising about 60 to about 75% by weight of woven magnesium aluminosilicate glass fiber roving impregnated with calcium hydroxide and isophthalic acid thermosetting polyester.

US Pat. Nos. 4,842,923 and 5,167,876 describe composites in which multiple layers of magnesium aluminosilicate glass fiber networks are equilibrated in a cured phenolic resin matrix having an areal density of at least 2.5 pounds per square foot.

US Patent 5,167,876 describes a composite material comprising two or more layers, at least one layer being a network of fibers in a substrate and at least one layer being a flame retardant layer having heat absorbing properties when heated.

U.S. Patent 5,480,706 describes a composite material comprising a plurality of alternating one-two layers, wherein the first layer includes a high-strength combustible fiber network in a first matrix, and the second layer includes a flame-retardant organic or Inorganic fiber network.

Each of the composite materials described above represents progress toward that goal. However, none of the documents describe the specific structure of the present invention, and none of the documents can satisfy all needs like the present invention.

The main disadvantages of these early composite materials included the use of denser inorganic materials such as glass fibers. This material is not ideal for use in aircraft interiors, where excess weight would result in unnecessary and uneconomical fuel consumption. On the other hand, the composite material density may be too low and take up too much space. Composite materials are therefore required to have strength, toughness, impact resistance and fire resistance along with applicable densities.

Brief description of the invention

The present invention provides composite materials that exhibit an unprecedented combination of strength, toughness, impact resistance, fire resistance, and usable density. The composite material of the present invention has a flexural modulus of at least about 80,000 psi (552 MPa), a flexural yield strength of at least about 800 psi (5.52 MPa), a flexural yield strength of about 0.9-1.5 psi (4.40- 5.86kg/m ² ), meet the requirements of the No. 14 U.S. Code of Federal Regulations on January 1, 2002, the fire resistance required by §25.853, and the US Federal Aviation Administration (FAA) Advisory Circular 25.795 on January 10, 2002 .2, tested using a 240 grain (15.6 g) mass of the .44 Magnum hollow point metal-backed bullet (JHP) and a 124 grain (8.0 g) mass of the 9mm full metal cased bullet (FMJRN) with at least approximately V0 velocity of 1430 ft/s (427m/s).

In one embodiment, the composite material of the present invention comprises multiple layers, wherein a first layer comprises a metal foil, a second layer comprises a flame retardant adhesive material and a third layer comprises multiple layers, each of said layers being contained in a substrate A network of flammable polymeric fibers having a tenacity of at least about 17 grams per denier, a tensile modulus of at least about 500 grams per denier, and an energy to break of at least about 20 joules per gram.

Detailed Description of the Invention

The present invention provides composite materials that exhibit an unprecedented combination of strength, toughness, impact resistance, fire resistance, and low density. The composite material of the present invention has a flexural modulus of at least about 80,000 psi (552 MPa), a flexural yield strength of at least about 800 psi (5.52 MPa), a flexural yield strength of about 0.9-1.5 psi (4.40- 5.86kg/m ² ), meet the requirements of the No. 14 U.S. Code of Federal Regulations on January 1, 2002, the fire resistance required by §25.853, and the US Federal Aviation Administration (FAA) Advisory Circular 25.795 on January 10, 2002 .2, tested using a 240 grain (15.6 g) mass of the .44 Magnum hollow point metal-backed bullet (JHP) and a 124 grain (8.0 g) mass of the 9mm full metal cased bullet (FMJRN) with at least approximately V0 velocity of 1430 ft/s (427m/s).

The flexural modulus (flexural modulus of elasticity) and flexural yield strength of the composite material of the present invention are measured according to the American Society for Testing and Materials (ASTM) standard test method ASTM D790-00.

14 CFR §25.853 describes the flammability standards for components within the nacelle. Internal spacer materials must meet the test requirements specified in Appendix F, Parts I, IV, and V.

Part I(a)1(i) of Appendix F of 14 CFR §25.853 specifically requires that the spacer material must be self-extinguishing when tested in an upright position. Test specimens must be at least 2 inches (5 cm) wide, 12 inches (30 cm) long, and no thicker than the minimum thickness qualified for use in aircraft. At least three samples must be tested and the results averaged. The samples were exposed to the flame of a Bunsen or Tirrill burner at a flame temperature of at least 1550°F (843°C). The flame was applied under the sample along the centerline for 60 seconds and then removed. The average ignition time after removal from the ignition source shall not exceed 15 seconds. The average burn length should not exceed 6 inches (15cm). If dripped, the dripped sample shall not burn for more than an average of 3 seconds after the drip.

Part IV of Appendix F of 14 CFR §25.853 specifies the maximum heat release rate for cabin materials exposed to radiant heat in a specially designed test chamber. The sample is placed in a radiant heat source which is adjusted to produce a total heat flux of 3.4 W/ ^cm2 on the sample during the five minute test period. Coupon Sample dimensions were 5.91 inches by 5.91 inches (14.9 cm by 14.9 cm) and the same thickness as used for aircraft. Test specimens are tested standing upright on the exposed surface. The combustion products leaving the test chamber are monitored to calculate the heat release rate. Three or more samples were averaged to obtain the total positive exotherm at the first two minutes of exposure, and the peak exotherm rates of the samples were also averaged. The average peak heat release rate must not exceed 65 kW/m ² . If conditions such as melting, sagging, delamination, etc. occur affecting exposed surface area or mode of combustion, these conditions must be reported together with the time of occurrence.

Part V of Appendix F of Code of Federal Regulations No. 14 § 25.853 specifies the maximum smoke emission characteristics of cabin materials. For detailed test procedures, refer to ASTM F814-83. A minimum of three samples were tested and the results averaged. Install the 3×3 inch (7.62×7.62cm) specimen vertically in a specially designed chamber. The electrothermal radiant energy source produces an average radiation level of 2.2 BTU/s-ft ² (2.5W/cm ² ) in the center of the 1.5 inch (3.81 cm) diameter sample. A row of equidistant flames is applied along the lower edge of the exposed sample zone using a six-tube burner. Record the specific optical smoke density (Ds) at 1.5 minutes and 4 minutes, as well as the maximum optical smoke density value (DsMax) and its time. Average DsMax must not exceed 200.

The V0 velocity of a composite material is the maximum velocity at which a projectile is specified without penetrating the composite material. The V0 speed of the composite material of the present invention is by the test method of FAAAC 25.795.2 on January 10th, 2002, using the .44Magnum hollow tip metal back shell of 240 grains (15.6g) quality and the 124 grains (8.0g) quality Determination of 9mm full metal casing bullet.

The velocity of the projectile is measured by lumiline screens along the trajectory of the projectile. For each projectile, the test board was mounted perpendicular to the projectile trajectory in four shots and at 30° from vertical for two shots. V0 velocity was determined by varying the propellant charge to cause full or partial penetration of the test panel at each impact angle. The V0 velocity is the highest partial penetration velocity. The composites of the present invention have at least about 1430 ft/s when tested using a 240 grain (15.6 g) mass of .44 Magnum hollow point metal-backed bullet and a 124 grain (8.0 g) mass of 9 mm full metal cased bullet. (427m/s) V0 speed.

In one embodiment, the composite material of the present invention comprises multiple layers bonded together, wherein the first layer is a metal foil, the second layer is a flame retardant adhesive material, the third layer consists of multiple layers, each of the The layer comprises a network of combustible polymeric fibers in a substrate having a tenacity of at least about 17 grams per denier, a tensile modulus of at least about 500 grams per denier, and an energy to break of at least about 20 joules per gram .

In another embodiment, the composite material of the present invention comprises multiple layers bonded together, wherein the first layer is a metal foil, the second layer is an expanded resin composition, the third layer is a flame retardant adhesive material, the fourth layer is a The layer is comprised of multiple layers, each of said layers comprising a network of combustible polymer fibers having a tenacity of at least about 17 grams per denier, a tensile modulus of at least about 500 grams per denier, in a substrate and an energy-to-break of at least about 20 joules/gram.

Preferably the composite material according to the invention possesses a symmetrical layer structure with the central layer being a network of combustible polymer fibers in the matrix. In a preferred embodiment, the composite material comprises five layers bonded together, wherein the first and fifth layers are metal foils, the second and fourth layers are flame retardant adhesive materials, the third The layer is a network of combustible polymer fibers having a tenacity of at least about 17 grams per denier, a tensile modulus of at least about 500 grams per denier, and an energy to break of at least about 20 joules per gram in a substrate .

In another preferred embodiment, the composite material comprises seven layers bonded together, wherein the first and seventh layers are metal foils, the second and sixth layers are expanded resin compositions, the third and seventh layers are The five layers are a flame retardant binder material, and the center fourth layer is a network of flammable polymer fibers in a substrate having a tenacity of at least about 17 g/denier, a tensile strength of at least about 500 g/denier A modulus and an energy to break of at least about 20 Joules/gram.

The various layers in each embodiment are bonded and bonded together. Preferably the layers are thermocompression bonded. Preferably, the bonding is performed at a temperature of about 100 to about 150°C and a pressure of about 15 to about 5,000 psi (103-34,475 kPa) for a time sufficient to bond the layers together. More preferably, the bonding is performed at a temperature of about 120 to about 130° C. and a pressure of about 50 to about 200 psi (345-1,380 kPa) for a period of about 30 minutes.

Preferably the metal foil in various embodiments is aluminum foil having a thickness of about 0.0005 to about 0.005 inches (12.7-127 microns). More preferably the metal foil is aluminum foil having a thickness of about 0.001 to about 0.003 inches (25.4-76.2 microns).

Preferably said refractory binding material comprises at least 10% by weight of a polymeric material selected from thermoplastic and thermosetting polymers. Thermoplastic polymers useful in the adhesive material of the present invention include, but are not limited to: polyolefins, polydienes, polyesters, formamides, vinyl polymers, ionomers, acrylic polymers, acrylic polymers compounds, polysulfones, polyphenylene ethers, acetals, polysiloxanes, thermoplastic polyurethanes, thermoplastic polyimides, polyketones and their copolymers and halogenated derivatives. Useful thermoset polymers include, but are not limited to, phenolic polymers, melamine polymers, epoxides, polysiloxanes, unsaturated polyesters, and thermoset polyurethanes.

The polymeric portion of the flame retardant adhesive material may be inherently fire resistant, or may be rendered fire resistant by the incorporation of flame retardant additives.

The flame retardant additive, if present, may be an organic, inorganic or organometallic additive. Examples of suitable flame retardant additives include (but are not limited to) those found in "Flame Retardancy of Polymeric Materials", Vol. 1, Kuryla and Papa eds., Marcel Dekker, Inc., New York, 1973 Additives listed. The additives include the following organic additives:

PH functional group

-OH functional group

CH ₂ =CH- functional group

(CH ₂ ＝CHCH ₂ O ₃ P

(CH ₂ =CHCH ₂ OP=O

-NH functional group

PCH ₂ OH) ₄ A

R ₄ P salt

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

n=1 to 2

P-Cl functional group

P + S compound

functional group

(CH ₃ ) ₂ PSSP(CH ₃ ) ₂

P + Br compound

(BrCH ₂ CHBrCH ₂ O ₃ P=O

(XCH ₂ CHXCH ₂ O ₃ P=O

X = Cl, Br

P + Cl compound

(ClCH ₂ CH ₂ O ₃ P

(ClCH ₂ CHClCH ₂ O ₃ P=O

(ClCH ₂ CH ₂ H ₂ O ₃ P=O

(CH ₃ CHClCH ₂ O ₃ P=O

P(phosphite)

(CH ₃ O ₃ P

(CH ₃ CH ₂ O ₃ P

(C ₈ H ₁₇ O ₃ P

(C ₁₂ H ₂₅ O ₃ P

(C ₁₈ H ₃₇ O ₃ P

(C ₁₈ H ₃₇ O ₃ P

P (phosphate)

(CH ₃ O ₃ P=O

(C ₂ H ₅ O) ₃ P=O

(C ₂ H ₅ O ₃ P=O

(C ₄ H ₉ O ₃ P=O

(C ₈ H ₁₇ O ₃ P=O

(C ₈ H ₁₇ O ₃ P=O

(C ₄ H ₉ O-CH ₂ CH ₂ O ₃ P=O

R = H, _CH3

R=H, (CH ₃ ) ₂ CH

P(phosphonate)

P (multiple)

(nC ₄ H ₉  ₃ P=O

(nC ₈ H ₁₇  ₃ P=O

P + S compound

( _C1 2H ₂₅ S ₃ P

(CH ₃ CH ₂ O ₃ P=S

(C ₈ H ₁₇ O ₃ P=S

Bromo compounds: -OH functional group

(BrCH ₂  ₃ C-OH

BrCH=CBr- _CH2OH

_{BrCH2CH2OH _}

_{BrCH2CHBrCH2OH _}

Chlorine-based compounds: -OH functional group

Cl ₂ and

-C≡C- functional group

Cl-CH ₂ -C≡C-CH ₂ Cl

N-halogen functional group

H ₂ C=C- functional group

_CH2 =CH-Br

_CH2 =CH- _CH2Br

CH ₂ =CCl ₂

_CH2 =CH- _CH2Cl

-COOH functional group

(And NH ₄ ⁺ Salt)

-CHO functional group

BrCH ₂ CHBr-CHO

Cl ₃ C-CHO

_-NH2 functional group

non-functional halogen compound

bromo compounds

BrCH ₂ Cl

Br ₂ CH-CHBr ₂

_{BrCH2CH2CHCl _}

_{BrCH2CHBrCHBrCH2Br _}

_{( BrCH2CHBrCH2O ) 2CH2}

x+y=5

x+y=8

Chlorine-based compounds

Cl ₃ C-CCl ₃

_{ClCH2CHClCH2Cl _}

Cl ₂ C=CCl-CCl=CCl ₂

Chloro-tri(and higher)phenyl

Brominated and Chlorinated Biphenyls

X ₆ =Cl

X ₄ =Br

x+y=8

(x+y=1-10)

Chloro-naphthalene

Halogenated paraffin

Y = Br, H

Y = H, Cl

Y = H, Cl

Suitable inorganic flame retardant additives include: antimony oxide (Sb ₂ O ₃ ), antimony sulfides (Sb ₂ OS ₃ , Sb ₂ S ₃ , Sb ₂ S ₄ ), antimony halides (SbCl ₃ , SbCl ₅ , SbBr ₃ , SbBr ₅ ), sodium antimonate or potassium antimonate such as (NaSBO ₃ ), ammonium phosphate, sodium phosphate or potassium phosphate such as [(NH ₄ ) ₃ PO ₄ , (NH ₄ ) ₂ HPO ₄ , (NH ₄ )H ₂ PO ₄ , (NH ₄ PO ₃ ) _x ], phosphorus halides (PCl ₃ , PCl ₅ , POCl ₃ ), phosphazene chloride (PNCl ₂ ) _x , phosphorus pentasulfide (P ₂ S ₅ ), sodium borate [Na ₂ O(B ₂ O ₃ ) _3.5 4H ₂ O, Na ₂ B ₄ O ₇ 10H ₂ O], sodium tetrafluoroborate, potassium tetrafluoroborate or ammonium tetrafluoroborate such as (NaBF ₄ ), calcium borate or barium borate such as [Ca( BO ₂ ) ₂ , Ca ₃ (BO ₃ ) ₂ ], lithium tetraborate, sodium tetraborate or potassium tetraborate such as (LiB ₄ O ₇ ), boric acid (H ₃ BO ₃ ), trimethoxyboroxane[ (CH ₃ OBO) ₃ ], alumina hydrate [Al ₂ O ₃ ·3H ₂ O, Al(OH) ₃ ], aluminum phosphate hydrate [Al ₂ O ₃ ·(AlPO ₄ ) _x ·(H ₂ O) _y ], sodium silicate [(Na ₂ O) _n (SiO ₂ ) _m ], ammonium bromide (NH ₄ Br), ammonium sulfate [(NH ₄ ) ₂ SO ₄ ], lithium silicate [LiO ₂ (SiO ₂ ) _5.9 , Li ₂ O(Na ₂ O) _n (SiO ₂ ) _m ], molybdenum oxide (MoO ₃ ), ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ (H ₂ O) _x ], molybdenum sulfide (MoS ₂ ) and sulfamide [(NH ₂ ) ₂ SO ₂ ].

Suitable organometallic flame retardant additives include:

Examples of suitable self-flame retardant polymers that can be used in the flame retardant adhesive material include halogenated polymers such as chlorinated polyethylene, polyvinyl chloride, poly(1,1-dichloroethylene), poly(chlorotrifluoroethylene), ), poly(1,1-dichloro-2-fluoroethylene), poly(1,2-dichloro-1,2-difluoroethylene), poly(1,1-difluoroethylene), poly(1, 2-difluoroethylene), poly(tetrafluoroethylene), poly(trifluoroethylene), poly(pentafluoroethyl)ethylene, poly(tetrafluoropentylethylene), poly(hexafluoropropylene), poly(2 , 3,3,3-tetrafluoropropene), poly(3,3,3-trifluoropropene), poly(heptafluoropropyl)vinyl, polyvinylidene fluoride, and polytribromostyrene , mixtures thereof and copolymers of the monomers constituting these polymers.

Examples of non-halogenated self flame retardant polymers that can be used in the flame retardant bonding material include melamine-formaldehyde, urea-formaldehyde, phenol-formaldehyde and other phenolic polymers and copolymers such as Borden Chemicals and Plastics as FIRE PRF2- 1000 is a formaldehyde-furfural-resorcinol-phenol product sold as a two-component monomer.

Preferably the flame retardant _bonding material comprises antimony oxide ( _Sb2O3 ), decabromodiphenyl ether and polychlorinated paraffins bonded in a polyacrylate resin named BOSTIK(R) 14-576-3 (Bostik Findley, Inc.). blends in mixtures.

The non-polymeric portion of the flame retardant adhesive material may comprise an intumescent composition. The intumescent composition works by forming an intumescent insulating layer of flame retardant material under the action of heat. Expandable materials can also decompose endothermicly.

The expansion composition carbonizes and expands more than five times its original thickness. The intumescent material protects the substrate from oxygen and/or prevents overheating and thus prevents or retards the spread of the flame. Expansion systems typically consist of polymers, char or carbon framework forming substances ("carbon formers"), expansion agents ("spumifics"), and acid forming substances. Organic polyhydroxy compounds such as pentaerythritol, dipentaerythritol, tripentaerythritol, starch and sucrose can be used as the carbon-forming compound. Examples of blowing agents are nitrogen-containing compounds such as melamine, melamine salts, melamine derivatives, urea, dicyandiamide and guanidine. Blowing agents cause the formation of an intumescent layer by generating an inert gas. Acid-forming substances generally use amino phosphate, ammonium phosphate, amine phosphates, ammonium polyphosphate and melamine phosphate.

Expanding compositions useful in the present invention are described, for example, in U.S. Patent Nos. , 4,442,157, 4,542,170, 4,380,593, 4,198,328 and 3,849,178.

In a preferred embodiment, the composite material of the invention comprises at least one layer of expanded resin composition. A preferred intumescent resin composition is Borden Chemical phenolic resin FIRE PRF2-1000 and about 8 to about 18% by weight includes melamine pyrophosphate (C ₃ H ₆ N ₆ ·H ₄ P ₂ O ₇ ) and bis A mixture of (melamine pyrophosphate) (bsi (melaminepyrophosphoric) acid) (C ₆ H ₁₂ N ₁₂ ·H ₄ P ₄ O ₇ ), sold by Broadview Technologies, Inc. under the tradename MAXICHAR(R).

Preferably, the expanded resin composition additionally comprises from about 2 to about 35% by weight glass pores such as soda-calcium borosilicate glass pores sold under the tradename 3M® SCOTCHLITE® glass pores by Minnesota Mining and Manufacturing Co. hole. Most preferably the glass pores are sized such that less than 5% by weight remains on a No. 80 US Standard sieve (177 microns).

Preferably at least one layer of the composite material of the present invention is comprised of multiple layers, each of said layers being a network of combustible polymer fibers in a substrate, said polymer fibers having a tenacity of at least about 25 g/denier, at least about 900 A tensile modulus in grams per denier and an energy to break of at least about 25 Joules per gram.

For the purposes of the present invention, fibers are elongated bodies whose length dimension is much greater than the transverse dimensions of width and thickness. Thus, the term fiber includes filaments, ribbons, strips, etc., of regular and irregular cross-section. A yarn is a bundle of filaments comprising many fibers or filaments.

The term "fibrous network" as used herein refers to a plurality of fibers arranged in a predetermined configuration, or a plurality of fibers assembled together to form twisted or untwisted yarns arranged in a predetermined configuration. The fiber network can have various structures. For example, the fibers or yarns may be formed into a felt or other nonwoven fabric, knitted or woven into a network by conventional techniques. According to a preferred network structure, the fibers in one layer may be unidirectionally aligned such that they are substantially parallel to each other along the normal fiber direction. Subsequent layers of such unidirectionally aligned fibers are preferably rotated relative to the preceding layer.

Combustible fibers are fibers that support combustion. Combustible fibers include unmodified polyolefins, polyesters, polyvinyl alcohol, and polyacrylonitrile.

Most preferably the fibrous network layers of the composite material are arranged such that the fiber direction of the unidirectional fibers of each network layer is rotated relative to the fiber direction of the unidirectional fibers of the adjacent layer. An example is a five layer laminate with the second, third, fourth and fifth layers rotated +45°, -45°, 90° and 0° relative to the first layer. A particularly preferred example is a fifty-layer laminate, alternating layers at 0° and 90° to each other.

Most preferably the combustible fibers comprising the composite material of the present invention are high strength polyethylene fibers. The high-strength polyethylene fibers used in the present invention are those having a tenacity of greater than or equal to about 17 g/d (grams per denier), an initial tensile modulus of equal to or greater than about 500 g/d, and equal to or greater than about 20 J/g breaking energy of polyethylene fibers. For the purposes of this invention, fiber tenacity, initial tensile modulus (elastic modulus), and energy to break are measured in yarn form according to ASTM D2256. Preferred fibers are those having a tenacity of greater than or equal to about 25 g/d, an initial tensile modulus of equal to or greater than about 900 g/d, and an energy to break of greater than or equal to about 25 J/g. Particularly preferred fibers are fibers having a tenacity of greater than or equal to about 30 g/d, an initial tensile modulus of greater than or equal to about 1200 g/d, and an energy to break of greater than or equal to about 30 J/g. Most preferred fibers are those having a tenacity of greater than or equal to about 30 g/d, an initial tensile modulus of greater than or equal to about 1200 g/d, and an energy to break of greater than or equal to about 40 J/g.

Such high-strength polyethylene fibers can be grown in solution as described in U.S. Patent 4,137,394 or 4,356,138, or as described in German Off. silk to form a gel structure. Polyethylene fibers can also be produced by rolling and drawing as described in US Patent 5,702,657, which is sold by ITS Industries Inc. under the tradename TENSYLON(R). The term polyethylene as used herein refers to a predominantly linear polyethylene material which may contain small amounts of branched chains or comonomers (not more than 5 modification units per 100 main chain carbon atoms), which may also contain blends of Not more than about 50% by weight of one or more polymer additives such as olefin-1 polymers (particularly low density polyethylene, polypropylene or polybutene), copolymers of monoolefins as main monomers, Oxidized polyolefins, grafted polyolefin copolymers and polyoxymethylene, or conventionally used low molecular weight additives such as antioxidants, lubricants, UV filters, colorants, etc.

Surprisingly, the composite material according to the invention meets the stringent fire resistance requirements of aircraft interior components, although the main part comprises a network of flammable fibers covered by a thin flame retardant surface layer. Without being bound by a particular theory of operation of the invention, it is believed that the fibrous network layer and the flame retardant surface layer work together to retard flame spread. The outer metal foil and flame retardant bonding material block oxygen and first retard the propagation of high temperature to the interior of the composite. When the hot front finally penetrates the outer layers of the composite, the combustible fibers shrink, creating interstitial spaces and retarding further propagation. This retardation is further enhanced in embodiments where the intumescent resin composition is located between the fibrous network layer and the surface of the composite. The overall effect is a highly efficient flame retardant composite material meeting the requirements of aircraft interiors with very wide safety margins.

The following examples are provided to provide a more complete understanding of the invention. The specific techniques, conditions, materials, proportions and reported data are used to illustrate the principles of the invention and should not be construed as limiting the scope of the invention. Specifically, the technique described is for the preparation of test specimens, but is readily scalable for use in serial production lines.

Example

Comparative Example 1

A nine-layer composite with a symmetrical layer structure was prepared as follows:

Layers 1 and 9: Type 302 stainless steel foil, 0.001 inch (0.0254 mm) thick;

Second and eighth layers: expanded resin composition;

The third and seventh layers: fiberglass impregnated with phenolic resin;

Layers 4 and 6: flame retardant pressure sensitive film adhesive; and

Fifth layer: 50 layers of unidirectional polyethylene fiber network in epoxy vinyl ester substrate.

The expanded resin composition that makes up the second layer and the eighth layer is the sheet material that is prepared as follows: prepare by 60.9% by weight two-component formaldehyde-furfural-resorcinol-phenol monomer (Borden DuriteFIRE PRF2-1000; A component -100pph, B component -24pph), 9.1% by weight containing melamine pyrophosphate (C ₃ H ₆ N ₆ ·H ₄ P ₂ O ₇ ) and bis(melamine pyrophosphate) (C ₆ H ₁₂ N ₁₂ · H ₄ P ₄ O ₇ ) expansion additive (Broadview Technologies MAXICHAR®) and 30% by weight glass vesicles (3M K1 type). The mixture was spread evenly on a silicone release paper to a thickness of 0.020 inches (0.51 mm), with another release paper placed on top. The mixture was cured into a solid sheet by heating on a press at about 200°F (93°C) for 30 minutes under a light pressure of about 1 psi (7 kPa). The edges of the sheet were straightened and the sheet was divided into two equal halves to form the second and eighth layers of the composite.

The impregnated glass fiber that constitutes the third and seventh layers is 57×54 lines/inch (22×21 lines/cm) four-way false satin weave E-glass fiber, 7781 type, with flame retardant LC 194 phenolic Resin (Lewcott Corp.) was pre-impregnated and had a thickness of approximately 0.095 inches (2.41 mm).

The flame retardant pressure sensitive film adhesives that make up the fourth and sixth layers are antimony oxide (Sb ₂ O ₃ ), decabromodiphenyl ether and polychlorinated paraffins in BOSTIK® 14-576-3 (Bostik Findley, Inc. ) in a blend of acrylate resin binders.

The fifth middle layer consists of 50 layers of high-strength polyethylene fibers arranged in one direction within a layer, and the fibers in adjacent layers are arranged at 90° to each other. The polyethylene fiber is a 1100 denier fiber having a tensile strength of about 3.1 GPa, an initial tensile modulus of about 107 GPa, and an elongation at break of about 3.3%, and contains about 500 kpsi (3.5 GPa) of ethylene oxide Base ester resin (SPECTRA SHIELD® VE PLUS from Honeywell International Inc.).

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

Testing of the composite material in accordance with Part IV of 14 CFR §25.853 Appendix F showed an average maximum heat release rate of 11 kW/m ² against the requirement of less than 65 kW/m ² . However, the panels had an areal density of 1.84 lbs/ft2 (8.99 kg/ ^m2 ) which was considered too high.

Comparative Example 2

A nine-layer composite material having the same layer structure as that of Comparative Example 1 was prepared except for the second layer and the eighth layer. The expanded resin compositions constituting the second and eighth layers were prepared as follows:

A two-component expansive epoxy resin containing melamine pyrophosphate and bis(melamine pyrophosphate) (INTUMAX® EP1115, Broadview Technologies, Inc.) was mixed together and spread flat on a silicone release paper to 0.020 inches ( 0.51mm), put another release paper on top. Glass vesicles are not included in the resin. The mixture was cured into a solid sheet by heating on a press at about 200°F (93°C) for 30 minutes under a light pressure of about 1 psi (7 kPa). The edges of the sheet were straightened and the sheet was divided into two equal halves to form the second and eighth layers of the composite.

The remaining layers of the composite were identical to the corresponding layers described in Comparative Example 1.

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

Testing of the composite material in accordance with Part IV of 14 CFR §25.853 Appendix F showed an average maximum heat release rate of 47 kW/ ^m2 . Although it is within the acceptable range, it is worse than 11 kW/m ² of the composite material containing glass vesicles prepared in Comparative Example 1. The composite had an improved areal density of 1.56 psi (7.62 kg/m ² ), considered roughly on the outer edge of acceptability.

Example 1

A seven-layer composite with a symmetrical layer structure was prepared as follows:

Layers 1 and 7: Aluminum foil, 0.003 inches (0.076mm) thick;

Second and sixth layers: expanded resin composition;

Layers 3 and 5: flame retardant pressure sensitive film adhesive; and

Fourth layer: 50 layers of unidirectional polyethylene fiber network in epoxy vinyl ester substrate.

The expanded resin compositions constituting the second and sixth layers were prepared as follows: 95.3% by weight of two-component expanded epoxy resin (INTUMAX® EP1115, Broadview Technologies, Inc.) and 4.7% by weight of glass vesicles (3M Type K1 ) mixture. The mixture was spread evenly on silicone release paper to a thickness of 0.016 inches (0.41 mm), with another release paper placed on top. The mixture was cured into a solid sheet by heating on a press at about 200°F (93°C) for 30 minutes under a light pressure of about 1 psi (7 kPa). The edges of the sheet were straightened and the sheet was divided into two equal halves to form the second and sixth layers of the composite.

The third and fifth layers that make up the flame retardant pressure sensitive film adhesive include antimony oxide (Sb ₂ O ₃ ), decabromodiphenyl ether and polychlorinated paraffins in BOSTIK® 14-576-3 (Bostik Findley, Inc. ) in a blend of acrylate resin binders.

The fourth middle layer consists of 50 layers of high-strength polyethylene fibers arranged in one direction within a layer, and the fibers in adjacent layers are arranged at 90° to each other. The polyethylene fiber is a fiber of 1100 denier, has a tensile strength of about 3.1 GPa, an initial tensile modulus of about 107 GPa and an elongation at break of about 3.3% and an energy at break of about 45 J/g, and has a tensile strength of about 500 kpsi ( 3.5GPa) epoxy vinyl ester resin substrate (SPECTRASHIELD® VE PLUS of Honeywell International Inc.).

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

The composite material of the present invention has an areal density of 1.22 lbs/ft2 (5.96 kg/ ^m2 ) which is considered acceptable. Composite materials were tested in accordance with 14 CFR §25.853 Appendix F of January 1, 2002 and by FAA Advisory Circular 25.795.2 of January 10, 2002, using 240 grains (15.6g) A mass of .44 Magnum hollow point metal-backed bullet and a mass of 124 grain (8.0 g) of a 9mm full metal cased bullet were measured.

The flexural modulus (flexural modulus of elasticity) and flexural yield strength of composite materials were determined according to ASTM D790-00 method. The results of these tests are presented in Table 1 together with data for other examples and comparative examples. The composite of Example 1 of the present invention (comprising flammable polyethylene fibers) meets all Federal Aviation Administration (FAA) specifications.

Example 2

A seven-layer composite material having the same structure as the composite material of Example 1 was prepared in the same manner. The composite had an areal density of 1.19 lbs/ft2 (5.82 kg/ ^m2 ) which was considered acceptable. The test results in Table 1 show that the composite material of Example 2 meets all FAA specifications.

Example 3

A seven-layer composite with a symmetrical layer structure was prepared as follows:

Layers 1 and 7: Aluminum foil, 0.003 inches (0.076mm) thick;

Second and sixth layers: expanded resin composition;

Layers 3 and 5: flame retardant pressure sensitive film adhesive; and

Fourth layer: 50 layers of unidirectional polyethylene fiber network in a thermoplastic elastomeric substrate (SPECTRA SHIELD(R) PCR PLUS from Honeywell International Inc.).

The expansion resin composition that constitutes the second layer and the sixth layer is prepared as follows: a two-component formaldehyde-furfural-resorcinol-phenol monomer (Borden Durite FIREPRF2-1000; A component-100pph, Component B - 24pph), 12.9% by weight containing melamine pyrophosphate (C ₃ H ₆ N ₆ ·H ₄ P ₂ O ₇ ) and bis(melamine pyrophosphate) (C ₆ H ₁₂ N ₁₂ ·H ₄ P ₄ O ₇ ) expansion additive (Broadview Technologies MAXICHAR®) and 12.9% by weight of glass vesicles (type 3MK1). The mixture was spread evenly on a silicone release paper to a thickness of approximately 0.016 inches (0.41 mm), with another release paper placed on top. The mixture was cured into a solid sheet by heating on a press at about 200°F (93°C) for 30 minutes under a light pressure of about 1 psi (7 kPa). The edges of the sheet were straightened and the sheet was divided into two equal halves to form the second and sixth layers of the composite.

The third and fifth layers that make up the flame retardant pressure sensitive film adhesive include antimony oxide (Sb ₂ O ₃ ), decabromodiphenyl ether and polychlorinated paraffins in BOSTIK® 14-576-3 (Bostik Findley, Inc. ) blends of polyacrylate resin binders.

The fourth layer in the middle consists of 50 layers of high-strength polyethylene fibers, in which the layers are arranged in one direction, and the fibers in adjacent layers are arranged at 90° to each other. The polyethylene fibers were 1100 denier fibers having a tensile strength of about 3.1 GPa, an initial tensile modulus of about 107 GPa, an elongation at break of about 3.3%, and an energy at break of about 45 J/g. The high strength polyethylene fiber network was in a substrate (SPECTRA SHIELD(R) VE PLUS from Honeywell International Inc.) composed of a thermoplastic elastomer with a tensile modulus of about 100 kpsi (6.9 kPa).

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

The composite of the present invention has an areal density of 1.19 lbs/ft2 (5.82 kg/ ^m2 ) which is considered acceptable. The test results in Table 1 indicate that the composite of Example 3 meets all Federal Aviation Administration (FAA) specifications.

Example 4

A five-layer composite with a symmetrical layer structure was prepared as follows:

Layers 1 and 5: Aluminum foil, 0.001 inch (0.025mm) thick;

Second and fourth layers: flame retardant pressure sensitive film adhesive (BOSTIK(R) 14-576-3); and

Third layer: 50 layers of unidirectional polyethylene fiber network in a thermoplastic elastomeric substrate (SPECTRA SHIELD(R) PCR PLUS from Honeywell International Inc.).

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

The composites of the present invention have an areal density that has been reduced to 1.0 lb/ft2 (4.89 kg/ ^m2 ) which is considered acceptable. The test results in Table 1 show that the composite material of Example 4 meets all the technical requirements of the FAA.

Example 5

Except for the third layer of the central layer, a five-layer composite material with the same symmetrical layer structure as in Example 4 was prepared. In this embodiment, the central layer comprises 50 layers of high strength polyethylene fibers arranged unidirectionally within the layers and the fibers in adjacent layers are aligned at 90° to each other. The polyethylene fiber is a 1100 denier fiber having a tensile strength of about 3.1 GPa, an initial tensile modulus of about 107 GPa, and an elongation at break of about 3.3%, among other yarn physical properties, and has a tensile strength of about 500 kpsi ( 3.5GPa) epoxy vinyl ester resin substrate (Honeywell International Inc.'s SPECTRA SHIELD ® VE PLUS) tensile modulus.

The layers of the composite were joined and bonded together in a press at a pressure of 100 psi (690 kPa) and a temperature of 121° C. for 30 minutes.

The composite of Example 5 also had an areal density of 1.0 lbs/ft2 (4.89 kg/ ^m2 ) which was considered acceptable. The test results in Table 1 show that the composite material of Example 5 meets all the technical requirements of the FAA.

Although the invention has been described in some detail above, it is to be understood that these details need not be strictly followed and that those skilled in the art may suggest numerous changes and modifications, all of which are within the scope of the invention as defined in the appended claims. .

Vertical burning test Comparative example and example number composite surface Expansive resin composition Glass vesicles in resin (%) SPECTRASHIELD® impact plate type Flexural modulus psi Flexural Yield Strength psi Heat release ratekW/m ² Smoke density DSmax Burn time sec Maximum burn length inches Maximum and longest burning particle sec Area density psf V0 ft/s FAA Technical Requirements ＜65 ＜200 ＜15 <6 <5 ＞1430 Comparative Example 1 SS Phenolic 30 VE Plus n.a. n.a. 11 95 0 1.5 0 1.84 n.a. Comparative Example 2 SS Epoxy 0 VE Plus n.a. n.a. 47 n.a. n.a. n.a. n.a. 1.56 n.a. 1 Al Epoxy 47 VE Plus n.a. n.a. 0 n.a. n.a. n.a. n.a. 1.22 ＞1430 2 Al Epoxy 4.7 VE Plus 676000 3344 0 16 0 0.2 0 1.19 ＞1430 3 Al Phenolic 12.9 PCR Plus 87930 937 1 9 0 0.8 0 1.19 ＞1430 4 Al none 0 PCR Plus n.a. n.a. 0 35 0 1.5 0 1.00 ＞1430 5 Al none 0 VE Plus n.a. n.a. 0 3 0 1.5 0 1.00 ＞1430

n.a.- no data

Claims (17)

1. composite, described composite have at least about the flexural modulus of 80,000 pounds/square inch (552MPa), at least about the flexural yield strength, about 0.9 of 800 pounds/square inch (5.52MPa) to about 1.5 pounds per square foot (4.40-5.86kg/m ²) surface density, satisfy No. 14 CFR on January 1st, 2002, the fire resistance that § 25.853 requires, and by the Advisory Circulars 25.795.2 of US Federal Aviation Administration on the 10th January in 2002, use the 9mm full metal jacket Round nose (FMJRN) that the empty sharp metal backing of .44Magnum of 240 grains (15.6g) quality is covered bullet (JHP) and 124 grains (8.0g) quality to test, have V0 speed at least about 1430 feet per seconds (427m/s).

2. composite that comprises the multilayer that is bonded together, wherein ground floor comprises metal forming, the second layer comprises the retardant adhesive material, the 3rd layer comprises multilayer, each described layer is included in the flammable polymer fiber network in the base material, and described polymer fiber has at least about the toughness at 17 gram/dawn, at least about the stretch modulus at 500 gram/dawn with at least about the energy to failure of 20 joule/gram.

3. the layer 5 that the 4th layer of comprising also that the retardant adhesive material constitutes of the composite of claim 2, described composite and metal forming constitute.

4. the composite of claim 2, described composite also is included in the swollen resin composition between the described ground floor and the second layer.

5. the composite of claim 4, described composite also comprise the layer 5 that is made of the swollen resin composition, the layer 6 that is made of the retardant adhesive material and the layer 7 that is made of metal forming.

6. the composite of claim 2 or claim 4, wherein said metal forming is for having the aluminium foil of about 0.0005 to about 0.005 inch (12.7-127 micron) thickness.

7. the composite of claim 2 or claim 4, wherein said retardant adhesive material comprises polymer adhesive, described polymer adhesive is selected from polyolefin, polydiene, polyester, polyamide, polyvinyl, ionomer, acrylic polymer, acrylic polymer, polysulfones, polyphenylene oxide, acetals, polysiloxane-based, thermoplastic polyurethane, TPI, the polyketone class, phenol polymer, the melamine polymer, epoxides, polysiloxane-based, unsaturated polyester (UP) class and heat-curable urethane class, with its copolymer and halo derivatives, and list in " Flame Retardancy of Polymeric Materials (fire resistance of polymeric material) ", the 1st volume, Kuryla and Papa compile, Marcel Dekker, Inc., New York, the 1-111 page or leaf, at least a fire retardant in 1973.

8. the composite of claim 2 or claim 4, wherein said fire retardant jointing material is antimony oxide (Sb ₂O ₃), deca-BDE and the blend of many chlorine paraffin in the polyacrylate resin adhesive.

9. the composite of claim 2 or claim 4, wherein said flammable polymer fiber is a polyethylene.

10. the composite of claim 9, wherein said polyethylene fibre one-way orientation in layer, and wherein at the fiber of adjacent layer mutually with about 90 ° of orientations.

11. the composite of claim 2 or claim 4, the elastomer of wherein said base material for having the initial tensile modulus that is lower than about 6000psi (41.4MPa) through ASTM D638 measurement.

12. the composite of claim 11, wherein said base material are the elastomer that comprises the block copolymer of conjugated diene and vi-ny l aromatic monomers.

13. the composite of claim 2 or claim 4, wherein said base material is for having the thermosetting resin at least about the stretch modulus of 300kpsi (2.1GPa).

14. the composite of claim 13, wherein said base material are epoxy vinyl ester resin.

15. the composite of claim 3, wherein said swollen resin composition comprises the blowing agent that is selected from melamine, melamine salt, melamine derivative, urea, dicyandiamide and guanidine, and described blowing agent is scattered in the resin that is selected from phenol polymer, melamine polymer, epoxy resin, polysiloxanes, unsaturated polyester (UP) and heat-curable urethane.

16. comprising, the composite of claim 4, wherein said swollen resin composition be selected from melamine pyrophosphate (C ₃H ₆N ₆H ₄P ₂O ₇) and two (melamine pyrophosphate) (C ₆H ₁₂N ₁₂H ₄P ₄O ₇) at least a and be selected from a kind of of formaldehyde-furfural-resorcinol-phenolic resin and epoxy resin.

17. the composite of claim 12, wherein said swollen resin composition also comprise the about 2 glass vesicles to about 35% weight.