Metal-thermoplastic-metal laminates and a process for the preparation of such laminates

Claim 2

A metal-thermoplastic-metal laminate having in combination: an inelastic ratio less than about 93%; a coefficient of linear thermal expansion less than about 63 x 10 -6 °C. -1 ; a heat distortion temperature of at least about 130°C.: and a maximum weight of no more than about 9.76 kg/m 2 ; said laminate comprising: a thermoplastic core layer selected from the group consisting of partly crystalline polyamides and polyesters having a crystalline melting point greater than about 130°C.; and a metal layer laminated on each side of the thermoplastic core layer, each metal layer having: a melting point greater than the crystalline melting point of the thermoplastic core layer; and a minimum thickness of about 0.00127 cm; wherein the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness is described by the region of numerical overlap of the parameter TR(YS m /TS c ) as determined from the areas defined by the relationships of TR(YS m /TS c ) to IR,, CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), the lower boundary of said areas being defined by the equation of a straight line in which y is the y-axis parameters of IR,, CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), x is the x-axis parameter of TR(YS m /TS c ), m is the slope of the straight line, and b is the intercept on the y-axis, with the proviso that: when y is IR,, m is 108 and b is zero (0) for values of x from zero (0) to 0.65, and m is zero (0) and b is 70 for values of x greater than 0.65; when y is CLTE,, m is -3.6 x 10 -4 and b is 45 x 10- 6 for values of x from zero (0) to 0.1, and m is zero (0) and b is 9 x 10 -6 for values of x greater than 0.1; and when y is (HDT l -HDT c )/(T mc -HDT c ), m is 1 and b is zero (0) for values of x from zero (0) to 0.05, m is 10 and b is -0.45 for values of x from 0.05 to 0.12, and m is zero (0) and b is 0.75 for values of x greater than 0.12; and the upper boundary of said areas being defined by the equation of a straight line as defined hereinabove, with the proviso that: when y is IR,, m is 280 and b is 30 for values of x from zero (0) to 0.25, and m is zero (0) and b is 100 for values of x greater than 0.25; when y is CLTE,, m is -2.88 x 10- 3 and b is 216 x 10- 6 for values of x from zero (0) to 0.05, m is -1.29 x 10- 4 and b is 78.5 x 10- 6 for values of x from 0.05 to 0.26, and m is zero (0) and b is 45 x 10- 6 for values of x greater than 0.26; and when y is (HD l -HDT c )/(T m -HDT c ), m is 112.5 b is zero (0) for values of x from zero (0) to 0.004, m is 15.3 and b is 0.389 for values of x from 0.004 to 0.04, and m is zero (0) and b is 1 for values of x greater than 0.04; wherein: IR, is the inelastic ratio of the laminate as measured in flexure at 5% strain in the outer metal layers at the point of maximum deflection; CLTE, is the coefficient of linear thermal expansion of the laminate; (HDT l -HDT c )/(T mc -HDT c ) is a normalized heat distortion temperature variable wherein HDT, is the heat distortion temperature of the laminate; HDT e is the heat distortion temperature of the thermoplastic core layer; T mc is the crystalline melting point of the thermoplastic core layer; TR is the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness; YS m is the thickness-weight-average tensile yield strength of the two metal layers at an offset of 5% elongation; and TS e is the tensile strength of the thermoplastic core layer.

Claim 3

The laminate of Claim 1 wherein the partly crystalline polyamides and polyesters are selected from the group consisting of thermoplastic compositions which have a partly crystalline polyamide or polyester portion having a degree of crystallinity of at least about 20%.

Claim 4

The laminate of Claim 1 wherein the thermoplastic core layer is a partly crystalline polyamide.

Claim 5

The laminate of Claim 3 wherein the partly crystalline polyamide is selected from the group consisting of nylon 6,6; nylon 6; and nylon 6-co-6,6.

Claim 6

The laminate of Claim 4 wherein the partly crystalline polyamide is nylon 6,6.

Claim 7

The laminate of Claim 3 wherein the partly crystalline polyamide is a partially aromatic nylon.

Claim 8

The laminate of Claim 6 wherein the partially aromatic nylon is a nylon 6, terephthalic acid-co-6, isophthalic acid.

Claim 9

The laminate of Claim 1 wherein the thermoplastic core layer is a partly crystalline polyester.

Claim 10

The laminate of Claim 8 wherein the partly crystalline polyester is a poly(alkylene terephthalate).

Claim 11

The laminate of Claim 9 wherein the poly(alkylene terephthalate) has an alkylene group containing from 2 to 10 carbon atoms.

Claim 12

The laminate of Claim 10 wherein the poly(alkylene terephthalate) is selected from the group consisting of poly(ethylene terephthalate) and poly(butylene terephthalate).

Claim 13

The laminate of Claim 10 wherein the poly(alkylene terephthalate) is a block copolymer modified poly(alkylene terephthalate).

Claim 14

The laminate of Claim 12 wherein the block copolymer-modified poly(alkylene terephthalate) is a poly(ethylene terephthalate)/poly(butylene tere-co-isophthalate)-b/ock-poly(butylene glycol) blend.

Claim 15

The laminate of Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13 wherein the thermoplastic core layer material contains an added modifying agent.

Claim 16

The laminate of Claim 14 wherein the added modifying agent is high modulus, high performance fibers.

Claim 17

The laminate of Claim 15 wherein the high modulus, high performance fibers are glass fibers.

Claim 18

The laminate of Claim 16 wherein the glass fibers are present in concentrations of between about 1% and about 45% by weight.

Claim 19

The laminate of Claim 14 wherein the added modifying agent is a mineral filler.

Claim 20

The laminate of Claim 18 wherein the mineral filler is present in concentrations of between about 1% and about 50% by weight.

Claim 21

The laminate of Claim 19 wherein the mineral filler is calcined kaolinite clay.

Claim 22

The laminate of Claim 1 wherein the metal layers laminated on each side of the thermoplastic core layer has the same composition.

Claim 23

The laminate of Claim 21 wherein the metal layers are selected from the group consisting of aluminum, low carbon steel and stainless steel.

Claim 24

The laminate of Claim 22 wherein the metal layers are aluminum.

Claim 25

The laminate of Claim 1 wherein the metal layers have different compositions.

Claim 26

The laminate of Claim 1 wherein the metal layers laminated on each side of the thermoplastic core layer are of equal thickness.

Claim 27

The laminate of Claim 1 wherein both the metal layers and the thermoplastic core layer are ductile.

Claim 28

The laminate of Claim 1 which is a substantially flat structure.

Claim 29

The laminate of Claim 1 which is a non-flat shaped structure.

Claim 30

The laminate of Claim 1 wherein the thermoplastic core layer and the metal layers are uniformly laminated together via an adhesion agent interposed between the facing surfaces thereof.

Claim 31

The laminate of Claim 29 wherein the adhesion agent is an organosilane adhesion promoter.

Claim 32

The laminate of Claim 30 wherein the organosilane adhesion promoter is an amino-functional alkyltrialkoxysilane.

Claim 33

The laminate of Claim 31 wherein the amino-functional alkyl-trialkoxysilane is selected from the group consisting of gamma-aminopropyltriethoxysilane and N-beta-(aminoethyl)-gamma- aminopropyltrimethoxysilane.

Claim 34

The laminate of Claim 30 wherein the organosilane adhesion promoter is a glycidoxy-functional alkyltrialkoxysilane.

Claim 35

The laminate of Claim 33 wherein the glycidoxy-functional alkyltrialkoxysilane is gamma-glycidoxypropyltrimethoxysilane.

Claim 36

The laminate of Claim 30 wherein the organosilane adhesion promoter is a methacryloxy- functional alkyltrialkoxysilane.

Claim 37

The laminate of Claim 35 wherein the methacryloxy-functional alkyltrialkoxysilane is gamma-methacryloxypropyltrimethoxysilane.

Claim 38

The laminate of Claim 30 wherein the organosilane adhesion promoter is a mixture of an amino-functional alkyltrialkoxysilane and a methacryloxy-functional alkyltrialkoxysilane.

Claim 39

The laminate of Claim 37 wherein the aminofunctional alkyltrialkoxysilane and the methacryloxy-functional alkyltrialkoxysilane of the mixture are gamma-aminopropyltriethoxysilane and gamma-methacryloxypropyltrimethoxysilane, respectively.

Claim 40

The laminate of Claim 29 wherein the adhesion agent is an adhesive.

Claim 41

The laminate of Claim 39 wherein the adhesive is an epoxy resin.

Claim 42

The laminate of Claim 1 suitable for use as an automobile body panel wherein: (a) the heat distortion temperature is at least about 135°C; (b) the coefficient of linear thermal expansion is less than about 45 x 10-60C.-l (c) the inelastic ratio is less than about 75%; and (d) the maximum weight is less than about 6.34 kg/m 2 surface area; said laminate further having a flexural stiffness of at least about 262.65 x 10 3 N/m.

Claim 43

A process for the preparation of a metal-thermoplastic-metal laminate having in combination: an inelastic ratio less than about 93%; a coefficient of linear thermal expansion less than about 63 x 10 -6 °C. -1 ; a heat distortion temperature of at least about 130°C.; and a maximum weight of no more than about 9.76 kg/m 2 ; which process comprises: disposing a metal layer on each side of a thermoplastic core layer selected from the group consisting of partly crystalline polyamides and polyesters having a crystalline melting point greater than about 130°C., each metal layer having a melting point greater than the crystalline melting point of the thermoplastic core layer and a minimum thickness of about 0.00127 cm; wherein the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness is described by the region of numerical overlap of the parameter TR(YS m /TS c ) as determined from the areas defined by the relationships of TR(YS m TS c ) to IR i , CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), the lower boundary of said areas being defined by the equation of a straight line in which y is the y-axis parameters of IR,, CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), x is the x-axis parameter of TR(YS m /TS c ), m is the slope of the straight line, and b is the intercept on the y-axis, with the proviso that: when y is IR,, m is 108 and b is zero (0) for values of x from zero (0) to 0.65, and m is zero (0) and b is 70 for values of x greater than 0.65; when y is CLTE,, m is -3.6 x 10 -4 and b is 45 x 10 B for values of x from zero (0) to 0.1, and m is zero (0) and b is 9 x 10- 6 for values of x greater than 0.1; and when y is (HDT l -HDT c )/(T mc -HDT ° ), m is 1 and b is zero (0) for values of x from zero (0) to 0.05, m is 10 and b is -0.45 for values of x from 0.05 to 0.12, and m is zero (0) and b is 0.75 for values of x greater than 0.12; and the upper boundary of said areas being defined by the equation of a straight line as defined hereinabove, with the proviso that: when y is IR,, m is 280 and b is 30 for values of x from zero (0) to 0.25, and m is zero (0) and b is 100 for values of x greater than 0.25; when y is CLTE,, m is -2.88 x 10- 3 and b is 216 x 10- 6 for values of x from zero (0) to 0.05, m is -1.29 x 10- 4 and b is 78.5 x 10- 6 for values of x from 0.05 to 0.26, and m is zero (0) and b is 45 x 10- 6 for values of x greater than 0.26; and when y is (HDT l -HDT c )/(T mc ), m is 112.5 and b is zero (0) for values of x from zero (0) to 0.004, m is 15.3 and b is 0.389 for c values of x from 0.004 to 0.04, and m is zero (0) and b is 1 for values of x greater than 0.04; wherein: IR, is the inelastic ratio of the laminate as measured in flexure at 5% strain in the outer metal layers at the point of maximum deflection; CLTE, is the coefficient of linear thermal expansion of the laminate; (HDT l -HDT c )/(Tm c -HDT c ) is a normalized heat distortion temperature variable wherein HDT, is the heat distortion temperature of the laminate; HDT c is the heat distortion temperature of the thermoplastic; T mc is the crystalline melting point of the thermoplastic core layer; TR is the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness; YS m is the thickness-weight-average tensile yield strength of the two metal layers at an offset of 5% elongation; and TS c is the tensile strength of the thermoplastic core layer; laminating the thermoplastic core layer and the metal layers by subjecting the combination to elevated temperatures and a pressure sufficient to maintain face-adhering contact; and cooling to ambient temperatures.

Claim 44

A process for the preparation of a metal-thermoplastic-metal laminate having in combination: an inelastic ratio less than about 93%; a coefficient of linear thermal expansion less than about 63 x 10 -6 °C. -1 ; a heat distortion temperature of at least about 130°C.; and a maximum weight of no more than about 9.76 kg/m 2 ; which process comprises: disposing a metal layer on each side of a thermoplastic core layer selected from the group consisting of partly crystalline polyamides and polyesters having a crystalline melting point greater than about 130°C., each metal layer having a melting point greater than the crystalline melting point of the thermoplastic core layer and a minimum thickness of about 0.00127 cm; wherein the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness is described by the region of numerical overlap of the parameter TR(YS m /TS c ) as determined from the areas defined by the relationships of TR(YS m TS c ) to IR i , CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), the lower boundary of said areas being defined by the equation of a straight line in which y is the y-axis parameters of IR,, CLTE,, and (HDT l -HDT c )/(T mc -HDT c ), x is the x-axis parameter of TR(YS m /TS c ), m is the slope of the straight line, and b is the intercept on the y-axis, with the proviso that: when y is IR,, m is 108 and b is zero (0) for values of x from zero (0) to 0.65, and m is zero (0) and b is 70 for values of x greater than 0.65; when y is CLTE,, m is -3.6 x 10 -4 and b is 45 x 10 B for values of x from zero (0) to 0.1, and m is zero (0) and b is 9 x 10- 6 for values of x greater than 0.1; and when y is (HDT l -HDT c )/(T mc -HDT ° ), m is 1 and b is zero (0) for values of x from zero (0) to 0.05, m is 10 and b is -0.45 for values of x from 0.05 to 0.12, and m is zero (0) and b is 0.75 for values of x greater than 0.12; and the upper boundary of said areas being defined by the equation of a straight line as defined hereinabove, with the proviso that: when y is IR,, m is 280 and b is 30 for values of x from zero (0) to 0.25, and m is zero (0) and b is 100 for values of x greater than 0.25; when y is CLTE,, m is -2.88 x 10- 3 and b is 216 x 10- 6 for values of x from zero (0) to 0.05, m is -1.29 x 10- 4 and b is 78.5 x 10- 6 for values of x from 0.05 to 0.26, and m is zero (0) and b is 45 x 10- 6 for values of x greater than 0.26; and when y is (HDT l -HDT c )/(T mc ), m is 112.5 and b is zero (0) for values of x from zero (0) to 0.004, m is 15.3 and b is 0.389 for c values of x from 0.004 to 0.04, and m is zero (0) and b is 1 for values of x greater than 0.04; wherein: IR, is the inelastic ratio of the laminate as measured in flexure at 5% strain in the outer metal layers at the point of maximum deflection; CLTE, is the coefficient of linear thermal expansion of the laminate; (HDT l -HDT c )/(Tm c -HDT c ) is a normalized heat distortion temperature variable wherein HDT, is the heat distortion temperature of the laminate; HDT c is the heat distortion temperature of the thermoplastic; T mc is the crystalline melting point of the thermoplastic core layer; TR is the thickness ratio of the sum of the metal layer-thicknesses to the thermoplastic core layer thickness; YS m is the thickness-weight-average tensile yield strength of the two metal layers at an offset of 5% elongation; and TS c is the tensile strength of the thermoplastic core layer; laminating the thermoplastic core layer and the metal layers by subjecting the combination to elevated temperatures and a pressure sufficient to maintain face-adhering contact; and cooling to ambient temperatures.

Claim 45

The process of Claim 42 wherein the elevated temperatures are between about 100°C. and 350°C.

Claim 46

The process of Claim 42 wherein an adhesion agent is interposed between the facing surfaces of the metal layers and the thermoplastic core layer.

Claim 47

The process of Claim 44 wherein the adhesion agent is an organosilane adhesion promoter.

Claim 48

The process of Claim 45 wherein the organosilane adhesion promoter is an amino-functional alkyltrialkoxysilane.

Claim 49

The process of Claimn 46 wherein the amino-functional alkyltrialkoxysilane is selected from the group consisting of gamma-aminopropyltriethoxysilane and N-beta-(aminoethyl)-gamma- aminopropyltrimethoxysilane.

Claim 50

The process of Claim 45 wherein the organosilane adhesion promoter is a glycidoxy-functional alkyltrialkoxysilane.

Claim 51

The process of Claim 48 wherein the glycidoxy-functional alkyltrialkoxysilane is gamma-glycidoxypropyltrimethoxysilane.

Claim 52

The process of Claim 45 wherein the organosilane adhesion promoter is a methacryloxy- functional alkyltrialkoxysilane.

Claim 53

The process of Claim 50 wherein the methacryloxy-functional alkyltrialkoxysilane is gamma-methacryloxypropyltrimethoxysilane.

Claim 54

The process of Claim 45 wherein the organosilane adhesion promoter is a mixture of an amino-functional alkyltrialkoxysilane and a methacryloxy-functional alkyltrialkoxysilane.

Claim 55

The process of Claim 52 wherein the aminofunctional alkyltrialkoxysilane and the methacryloxyfunctional alkyltrialkoxysilane are gamma-aminopropyltriethoxysilane and gamma-methacryloxypropyltrimethoxysilane, respectively.

Claim 56

The process of Claim 44 wherein the adhesion agent is an adhesive.

Claim 57

The process of Claim 54 wherein the adhesive is an epoxy resin.

Claim 58

The process of Claim 42 which further comprises: (a) applying a weather resistant protective coating to at least one of the metal surfaces of the metal-thermoplastic-metal laminate; (b) curing the protective coating at elevated temperatures; and thereafter (c) cooling to ambient temperatures.

Claim 59

A process for the preparation of a metal-thermoplastic-metal laminate which comprises: (a) orienting two metal layers to provide a spatial separation therebetween; and (b) casting a thermoplastic core layer between the two metal layers by in situ polymerization therebetween of monomeric material at polymerization conditions.

Claim 60

A process for the preparation of a metal-thermoplastic-metal laminate which comprises: (a) orienting two metal layers to provide a spatial separation therebetween; and (b) casting a thermoplastic core layer between the two metal layers by in situ polymerization therebetween of monomeric material at polymerization conditions.

Claim 61

The process of Claim 57 wherein the monomeric material is E -caprolactam and the thermoplastic core layer is nylon 6.

Claim 62

The process of Claim 57 wherein the monomeric material is. E -caprolactam, an acyl-bis-caprolactam, and polyoxypropylene glycol and the thermoplastic core layer is a nylon 6/polyoxypropylene block copolymer.

Claim 63

The process of Claim 59 wherein the acyl-bis-caprolactam is isophthaloyl-bis-caprolactam.

Claim 64

The process of Claim 57 wherein the monomeric material is E -caprolactam admixed with calcined kaolinite clay and the thermoplastic core layer is a calcined kaolinite clay reinforced nylon 6.

Claim 65

The process of Claim 61 wherein the calcined clay reinforced nylon 6 is a 20% to 45% calcined kaolinite clay reinforced nylon 6.