WO2020081323A1

WO2020081323A1 - Polymer metal hybrid support beams

Info

Publication number: WO2020081323A1
Application number: PCT/US2019/055379
Authority: WO
Inventors: Robert A. Coy; Paul J. Kane; Everette R. RINEHART
Original assignee: Dupont Polymers, Inc.
Priority date: 2018-10-09
Filing date: 2019-10-09
Publication date: 2020-04-23

Abstract

Provided herein are overmolded polymer-metal hybrid (PMH) support beams. These beams comprise a surface layer that includes at least one polyamide or polypropylene layer, or at least one adhesive layer; a metal support beam; and a polymer composition overmolded onto the surface layer. Further provided herein are methods of making the overmolded PMH support beams and articles comprising the overmolded PMH support beams.

Description

TITLE OF THE INVENTION

Polymer Metal Hybrid Support Beams

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority under 35 U.S.C. § 365 to U.S. Provisional

Application No. 62/743,094, filed on October 9, 2018, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of light-weight replacements for metal parts. In particular, polymer-metal hybrid structures, in which an overmolded polymer composition is adhered to a metal substrate, are provided herein.

BACKGROUND OF THE INVENTION

Several patents and publications are cited in this description in order to more fully describe the state of the art to which this invention pertains. The entire disclosure of each of these patents and publications is incorporated by reference herein.

Described herein are polymer-metal hybrid support beams, overmolded polymer- metal hybrid support beams, materials used to prepare these polymer-metal hybrid support beams, and improved processes for preparing these support beams. Particularly, it relates to the field of high pressure (e.g., injection molding and compression molding) formed polymer-metal hybrid support beams to which may be attached at least one polymeric structure by overmolding. The overmolded polymeric structures can be attached using high pressure overmolding techniques. The polymer-metal hybrid support beams, before high pressure overmolding, comprise at least one surface layer A.

Polymer-metal hybrid (PMH) support beams are much lighter than identical parts prepared from metal and have comparable mechanical performance to the metal-only counterparts. As a result, PMH support beams are increasingly being used as

replacements for metal parts to reduce weight in highly demanding applications, such as for example support beams in automotive and aerospace applications. By combining plastic and metal together, manufactures are provided with new design capabilities, part integration possibilities, improved noise and vibration harshness performance, and overall light-weighting. Traditional PMH support beams are prepared by overmolding of the metal component in which the overmolded polymer is typically attached to the metal component by mechanical interlocking and/or adhesives.

U.S. Patent No. 5,190,803 discloses overmolded PMH articles in which the metal and plastic are mechanically interlocked to provide the final overmolded article.

U.S. Patent Application No. 2016/0243794 discloses surface treated metal sheets consisting of a laminate having a metal substrate, a chemical conversion coating film and an adhesive layer in order wherein the chemical conversion coating film contains colloidal silica and a thermosetting polymer.

U.S. Patent Application No. 2013/0264741 discloses laminated adhesive films which include a laminate of a tacky adhesive film containing a modified polyolefin polymer and an unmodified tacky thermoplastic polymer film.

Alternative methods or compositions may be used to prepare the surface of metals for overmolding to produce PMH support beams. For example, the surface of the metal may be treated by laser ablation, on one or both sides of the metal surface, to improve adhesion of an overmolded polymer onto the metal surface. Nano etching of the metal surface may also be performed using an acid. An additional alternative method involves coating of the metal surface(s) with an adhesive material such as Evonik’s Vestamelt® Hylink adhesion promoter which is based on a copolyamide or applying a silane-based adhesive onto the surface of the metal.

Nevertheless, it remains desirable to prepare PMH support beams, especially PMH support beams which are used as automotive cross beams, in which a high pressure overmolded polymeric structure is attached to the PMH support beam by improved chemical bonding or a combination of chemical bonding and mechanical interlocking and which exhibit significantly improved physical properties, especially after environmental exposure, such as superior torsional stiffness, bending stiffness, cross car beam system first mode frequency, flexural modulus and lap shear strength compared to traditionally prepared overmolded PMH support beams.

It has now been discovered that overmolded PMH support beams can be prepared which provide desirable adhesion between the PMH support beam and the overmolded polymeric structure as well as providing improved structural rigidity by the use of beam inserts at the overmolding locations of the support beam. The use of novel surface layers on the PMH support beam allows for strong adhesion between the PMH support beam and the overmolded polymeric structure. Additionally, the use of these PMH support beams in high pressure overmolding processes provides overmolded PMH support beams without undesirable deformation of the support beam.

SUMMARY OF THE INVENTION

Provided herein are overmolded polymer-metal hybrid (PMH) support beams. These beams comprise a surface layer that includes at least one polyamide or

polypropylene layer, or at least one adhesive layer; a metal support beam; and a polymer composition overmolded onto the surface layer. Further provided herein are methods of making the overmolded PMH support beams and articles comprising the overmolded PMH support beams.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure l is a perspective view of a metal layer with openings.

Figure 2 is a cross-sectional view of a PMH support beam.

Figure 3 is a perspective view of an overmolded PMH support beam with openings. Figure 3 A is a cross-sectional view of the overmolded section of a PMH support beam with openings.

Figure 4 is a perspective view of an insert for a PMH support beam.

Figure 4A is a perspective view of an insert inside a PMH support beam.

Figure 4B is a perspective view of an overmolded PMH support beam with an insert inside.

DETAILED DESCRIPTION OF THE INVENTION

Abbreviations

The claims and description herein are to be interpreted using the following abbreviations:“h”,“hrs” refers to hours;“%” refers to the term percent;“wt %" refers to weight percent;“mol%” refers to mole percent;“mil” or“mils” refers to thousandths of an inch (1 mil is 0.001 inches);“cc” refers to cubic centimeter;“g” refers to grams;

“min” refers to minutes;“kg” refers to kilogram; and“mp” refers to melting point. Definitions

As used herein, the article "a" refers to one as well as more than one and does not necessarily limit its referent noun to the grammatical category of singular number.

As used herein, the term“nonfunctionalized thermoplastic polyolefin” refers to polyolefins which do not comprise carboxyl functional groups such as acid or anhydride functional groups.

As used herein, the term“functionalized thermoplastic polyolefin” refers to polyolefins which comprise carboxyl functional groups such as acid or anhydride functional groups.

As used herein, the term“carboxyl functional group” refers to groups that contain a carboxyl moiety or a derivative of a carboxyl moiety, including, without limitation, carboxylic acid groups; anhydride groups formed from two or more carboxylic acid groups; carboxylate esters; diesters or monoesters of dicarboxylic acids, such as maleic acid monoethyl ester; and carboxylate anions. The concentration of carboxyl functional groups in the functionalized polyolefins is measured according to ASTM E168-16-A5.

As used herein, the term“flexural modulus” refers to test values obtained on an overmolded polymer-metal hybrid test sample according to ISO 178. As used herein, when a sample is tested according to“ISO 178”, the standard method is ISOl78:20lOA, using a span of 50.8 mm, support radius of 5 mm, a nose radius of 5 mm and a cross-head speed of 50.8 mm/min. Samples were tested with the aluminum side, that is, the bare metal side, facing up. The polymer-metal hybrid test sample has an A/B/C structure in which A is a metal layer, B is an adhesive layer, and surface layer C can be overmolded or further bonded to polymer layer D.

As used herein, the term“spring constant” refers to the bending stiffness of PMH or overmolded PMH articles and is calculated from a 3-point bending formula, as described in the Examples, below, using data obtained from testing the samples using ISO 178:2010 A with a span of 50.8 mm, a support radius of 5 mm, a nose radius of 5 mm and a cross-head speed of 50.8 mm/min. Measurements were made with the uncoated metal side of the test samples facing upwards.

As used herein, the term“initial flexural modulus” refers to test values obtained on an overmolded polymer-metal hybrid test sample according to ISO 178 and before any thermal cycling (zero thermal cycles), humidity exposure (0 hrs.), or any other environmental exposure. The polymer-metal hybrid test sample has an A/B/C or A/B/C/D structure.

As used herein, the terms“lap shear” and“lap shear strength” refer to test values obtained according to ASTM D3163-01(2014). The test sample size was 25.4 mm wide with a lap length of 3.175 mm, and the cross-head speed was 0.05 inch/min. This test determines the interfacial adhesion or joint strength between two layers of materials. When multiple layers are present, such as 3 layers, test values represent the weakest adhesion value or joint strength between the various layers.

As used herein, the terms“initial lap shear” and“initial adhesion” refer to the interfacial adhesion between at least two layers of materials as formed before exposure to any environmental conditioning tests such as long term humidity exposure and/or elevated temperature cycles.

As used herein in descriptions of multilayer structures, the symbol

represents a boundary between contiguous layers. No third layer is interposed between two contiguous layers.

As used herein, the term“A/B/C structure” refers to a laminated structure or multilayer film comprising an adhesive layer B, a metal layer A, and a surface layer C in the stated order. Specifically, in an“A/B/C” structure, layer B is between layers A and C. Preferably, layer A is in direct contact with layer B. Also preferably, layer B is in direct contact with layers A and C.

Finally, suitable for use in the PMH articles, overmolded PMH articles, and methods described herein are the materials described as suitable for use in the

corresponding layers and elements of the PMH articles and overmolded PMH articles described in Inti. Patent Appln. Publn., Attorney Docket No. AD8218, claiming priority to U.S. Provisional Appln. No. 62/743,066 (filed October 9, 2018), filed concurrently herewith.

Ranges and Preferred Variants

Any range set forth herein expressly includes its endpoints unless explicitly stated otherwise. Any range set forth herein, for example a range of an amount, concentration, or other value or parameter, includes all possible ranges formed from any possible upper range limit and any possible lower range limit that are within the range, inclusive of the endpoints, regardless of whether such pairs of upper and lower range limits are expressly set forth herein. Compounds, processes and articles described herein are not limited to specific values disclosed in defining a range in the description.

The disclosure herein of any variation in terms of materials, chemical entities, methods, steps, values, and/or ranges, etc., whether identified as preferred or not, of the processes, compounds and articles described herein specifically includes any possible combination of materials, methods, steps, values, ranges, etc. For the purpose of providing photographic and sufficient support for the claims, any disclosed combination is a preferred variant of the processes, compounds, and articles described herein.

In this description, if there are nomenclature errors or typographical errors regarding the chemical name any chemical species described herein, including curing agents of formula (I), the chemical structure takes precedence over the chemical name. And, if there are errors in the chemical structures of any chemical species described herein, the chemical structure of the chemical species that one of skill in the art understands the description to intend prevails.

PMH Support Beams

Described herein are novel PMH support beams having a specific surface layer A on at least part of the surface of metal support beam B and having an A/B structure. When these PMH support beams are overmolded with a polymer, such as a polyamide, onto surface layer A, the resulting overmolded PMH support beams exhibit improved properties such as initial adhesion, high temperature adhesion, moisture resistance, and thermal stability compared to overmolded support beams using conventional adhesives.

The novel PMH support beams and overmolded PMH support beams described herein have very specific surface layer A compositions to achieve acceptable levels of adhesion between surface layer A and overmolded polymer C and between surface layer A and metal support beam B and wherein adhesion between layers is maintained under various environmental conditions such as high humidity and thermal cycling.

The ability to achieve the desired combination of properties of these overmolded PMH support beams is quite unexpected. The use of typical acid, epoxy, or anhydride containing adhesives alone as surface layer A does not typically provide the desired combination of properties and acceptable levels of adhesion between the various layers.

Another advantage of the PMH support beams is that they can be overmolded without the adhesive layer A2 causing fouling of the mold during the overmolding process.

Additionally, the novel PMH support beams may comprise at least one insert, said insert allowing the PMH support beam to be overmolded without undesirable

deformation of the support beam by the very high pressures used during the overmolding process.

Specifically, described herein are overmolded polymer-metal hybrid support beams comprising:

A) a surface layer comprising:

Al) at least one polyamide or polypropylene layer;

A2) at least one adhesive layer;

B) a hollow metal support beam having an interior and external surface and at least one opening on the external surface before overmolding: and

C) a polymeric composition overmolded onto surface layer A;

wherein:

adhesive layer A2 is in direct contact with polymer layer Al and in direct contact with at least part of a surface of metal support beam B;

overmolded polymer C is overmolded at least into one opening of said metal support beam; and

surface layer A is present on at least part of the polymer-metal hybrid support beam which is overmolded.

Also described herein are overmolded polymer-metal hybrid support beams comprising:

A) a surface layer comprising:

Al) at least one polyamide or polypropylene layer;

A2) at least one adhesive layer;

B) a hollow metal support beam having an interior and external surface; wherein

Bl) at least one insert is positioned inside hollow metal support beam B; and C) an overmolded polymer;

wherein:

surface layer A is present on at least part of the polymer-metal hybrid support beam which is overmolded;

polymeric insert Bl comprises ribs, said polymeric insert Bl being in direct contact with the interior surface of metal support beam B; and

overmolded polymer C is overmolded onto the exterior surface of metal support beam B at the location diametrically opposite the location of said polymeric insert Bl.

Further described herein are overmolded polymer-metal hybrid support beams comprising:

A) a surface layer comprising:

Al) a polyamide or polypropylene;

A2) at least one adhesive layer;

B) a hollow metal support beam having an interior and external surface and having at least one opening before overmolding; wherein

Bl) at least one polymeric insert is positioned inside metal support beam B;

C) an overmolded polymer;

wherein:

adhesive layer A2 is in direct contact with layer Al and in direct contact with at least part of the external surface of metal support beam B;

surface layer A is present on at least part of the polymer-metal hybrid support beam which is

overmolded;

overmolded polymer C is overmolded onto the exterior surface of metal support beam B and at the location diametrically opposite the location of said polymeric insert Bl. Also described herein are processes for preparing overmolded polymer-metal hybrid support beams comprising the steps of:

a) placing a polymer-metal hybrid support beam comprising a surface layer A into a heated mold on a molding machine with surface layer A facing outward, that is, towards the center of the mold, when inside the heated mold;

b) closing the heated mold and further heating the polymer-metal hybrid support beam to at least the T_g of polyamide or polypropylene of surface layer A;

c) injecting into the heated mold an overmolding polymer, wherein said

overmolding polymer is in direct contact with at least part of surface layer A of the polymer-metal hybrid support beam, to provide an overmolded polymer-metal hybrid support beam in which 90 percent or less of the polymer-metal hybrid support beam is overmolded;

d) allowing the overmolded polymer-metal hybrid support beam to cool;

e) opening the mold and removing the overmolded polymer-metal hybrid support beam;

wherein after 50 repetitions of steps (a) to (e), total mold deposits are 50 percent less than the total mold deposits of an identical process using a polymer-metal hybrid article lacking layer A.

Surface Layer A

Surface layer A may comprise a single polymer or may be a mixture of polymers and other ingredients to form surface layer Al which comprises at least a polyamide or a polypropylene. Surface layer Al may be applied to a metal sheet or metal surface which is used to prepare the hollow metal support beam B by any means known in the art, such as for example spraying, dipping, rolling or pressing a film of the composition of surface layer Al onto the metal surface, depending on the composition desired for surface layer A. Surface layer Al may also be applied to an already formed hollow metal support beam B.

Surface layer A may also comprise an adhesive layer A2 which is in direct contact with both surface layer Al and hollow metal support beam B. When adhesive layer A2 is present in surface layer A, surface layer Al is present as a film and is the outside layer (layer which is overmolded) of surface layer A and adhesive layer A2 is present in surface layer A as a film in direct contact with both the metal surface of hollow metal support beam B and surface layer Al . Adhesive layer A2 may be a thermoplastic material or a thermoset material. Thermoplastic materials are preferred for use in adhesive layer A2.

Surface Layer Al

Thermoplastic polymers or polymers useful in the preparation of surface layer Al described herein include without limitation, polypropylenes, polyamides, and

combinations of one or more polypropylenes with one or more polyamides. The thermoplastic polymers may be amorphous or semi-crystalline. Polyamides suitable for use as the thermoplastic polymer include aliphatic polyamides, semiaromatic polyamides, and copolyamides. Blends of polyamides with other polyamides or with different polymers may also be used.

Other thermoplastic resins suitable for use in combination with the polyamide(s) and polypropylene(s) of surface layer Al include, without limitation, polyethylenes, ethylene alpha-olefin copolymers, ethylene propylene diene rubbers (EPDM), polystyrenes, ionomers, copolymers of ethylene and vinyl alcohol, and combinations of two or more of these materials. The other thermoplastic resin(s) may be present in surface layer Al in an amount of less than 50 wt.%, preferably less than 30 wt.%, based on the total weight of the composition of surface layer Al.

Fully aliphatic polyamides may be formed from aliphatic and alicyclic monomers such as diamines, dicarboxylic acids, lactams, aminocarboxylic acids, and their reactive equivalents. A suitable aminocarboxylic acid includes l l-amino-dodecanedioic acid. As described herein, the term“fully aliphatic polyamide polymer” refers to copolymers derived from two or more such monomers and blends of two or more fully aliphatic polyamide polymers. Linear, branched, and cyclic monomers may be used. Star polymers may also be used. Carboxylic acid monomers useful in the preparation of fully aliphatic polyamides include, but are not limited to, aliphatic carboxylic acids, such as for example adipic acid (C6), pimelic acid (C7), suberic acid (C8), azelaic acid (C9), sebacic acid (C10), dodecanedioic acid (C12) and tetradecanedioic acid (C14). Useful diamines include those having four or more carbon atoms, including, but not limited to

tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2- methylpentamethylene diamine, 2-ethyltetramethylene diamine, 2-methyloctamethylene diamine; trimethylhexamethylene diamine and/or mixtures thereof. Suitable examples of fully aliphatic polyamide polymers include PA6; PA66, PA46, PA610, PA510, PA512, PA56, PA612, PA614, PA613, PA 615, PA616, PA618, PA11, PA12, PA10, PA 912, PA913, PA914, PA915, PA936, PA1010, PA1012, PA1013, PA1014, PA1016, PA1018, PA1210, PA1212, PA1213, PA1214, PA1216, PA1218, and copolymers and blends of the same.

Preferred aliphatic polyamides include poly(hexamethylene adipamide) (PA66), polycaprolactone (PA6), and poly(tetram ethylene hexanedi amide) (PA46), PA610, PA510, PA512, PA612, PA614, PA616, PA618, PA1010, PA1012, PA1013, PA1014, PA1016, PA1018, PA1210, PA1212, PA1213, PA1214, PA1216, PA1218, and PA6/66. Blends of any of the foregoing aliphatic polyamides are also suitable, especially blends of PA66 and PA6.

Preferred semiaromatic polyamides include poly(hexamethylene decanediamide /hexamethylene ter ephthal amide) (PA610/6T), poly(hexamethylene dodecanediamide /hexamethylene ter ephthal amide) (PA612/6T), poly(pentamethylene decanediamide/ pentamethylene ter ephthal amide) (PA510/5T), poly(pentamethylene dodecanediamide /pentamethylene ter ephthal amide) (PA512/5T), poly(hexamethylene terephthalamide/2- methylpentamethylene ter ephthal amide) (PA6T/DT); poly(decamethylene

ter ephthal amide) (PA10T), poly(nonamethylene terephthal amide) (PA9T),

hexamethylene adipamide/hexamethylene terephthalamide/hexamethylene

isophthalamide copolyamide (PA66/6T/6I); poly(caprolactam-hexamethylene

terephthal amide) (PA6/6T); and poly(hexamethylene terephthalamide/hexamethylene isophthalamide) (PA6T/6I) copolymer. Blends of aliphatic polyamides, semiaromatic polyamides, and less than about 20 wt. % other thermoplastic polymers and polymers, and combinations of these may also be used.

Polyamides used for surface layer Al should have a melting point ranging from about 140 to 280 °C, preferably from about 160 to 250 °C, and most preferably from about 170 to 250 °C. Rheology modifiers, heat stabilizers, colorants, antioxidants, lubricants, and other additives may be added as adjuncts to the thermoplastic polymers used to prepare surface layer Al.

The thermoplastic polymer may further comprise a toughener for increasing ductility of the thermoplastic polymer. Nonlimiting examples of tougheners which may be used in the thermoplastic polymers described herein include maleic anhydride grafted ethyl ene/propylene/hexadiene copolymers, ethylene/glycidyl (meth)acrylate copolymers, ethyl ene/glycidyl (meth)acrylate/(meth)acrylate esters copolymers, ethylene/a-olefm or ethyl ene/a-olefm/diene (EPDM) copolymers grafted with an unsaturated carboxylic anhydride, ethylene/2-isocyanatoethyl (meth)acrylate copolymers, ethylene/2- isocyanatoethyl (meth)acrylate copolymers/(meth)acrylate esters copolymers, and ethylene/acrylic acid ionomers.

Specific examples of ethylene/a-olefm/diene (EPDM) copolymers grafted with an unsaturated carboxylic anhydride include those grafted with from about 0.1 wt. % to 5 wt.% maleic anhydride, preferably from about 0.5wt. % to 4 wt. %, and more preferably from about 1 wt.% to 3 wt. %. Propylene is a preferred a-olefm. Specific examples of ethylene/a-olefm copolymers are those comprising from about 95-50 wt % ethylene and from about 5 to 50 wt% of at least one a-olefm with propylene, hexene, and octene being preferred a-olefms.

The additives and tougheners may be added to the composition of surface layer Al by methods that are generally known in the art, such as melt mixing, for example. Suitable amounts of additives are also known in the art. Preferably, however, no individual additive is present in an amount of greater than 1 or 5 wt%, and the sum of the weight percentages of the additives in surface layer Al is not greater than 2, 5, or 10 wt%, based on the total weight of the composition of surface layer Al . Suitable amounts of tougheners are also known in the art. Preferably, however, no individual toughener is present in an amount of greater than 50 wt.% of the total weight of the composition of surface layer Al. Preferably, the total weight of the toughener(s) in surface layer Al is from 1 to 15 wt.%.

The thickness of surface layer A may vary depending on the end use of the polymer-metal hybrid support beams which comprise surface layer A. For example, if a polymer-metal hybrid support beam is used as prepared (not overmolded), it may be beneficial to have a relatively thick surface layer A. In such an application, the thickness of surface layer A may range from about 0.001 inch (0.0254 mm) to 0.250 inch (6.35 mm), preferably from about 0.001 inch (0.0254 mm) to 0.250 inch (6.35 mm).

If polymer-metal hybrid support beams are to be overmolded, surface layer A need only be thick enough to provide the desired bond strength between the metal and overmolded polymer. In such applications, the thickness of surface layer A may range from about 0.0005 inch (0.0127 mm) to 0.100 inch (2.54 mm), preferably from about 0.001 inch (0.0254 mm) to 0.010 inch (0.254 mm). Adhesive Layer A2 need only be thick enough to achieve the desired bond level between Layer Al and the metal substrate. Adhesive layer A2 must be thick enough to ensure adequate coverage of the metal substrate surface depending on porosity and surface finish. Layer Al may be kept thin and then overmolded, or it may be made thick to provide strength or a protective layer over the entire article.

Surface layer Al may comprise a bilayer or multilayer films of different polyamides or polypropylenes.

Thermoplastic Adhesive Laver A2

In some preferred embodiments, Adhesive Layer A2 is a thermoplastic adhesive layer. Thermoplastic adhesive layer A2 used in surface layer A may be prepared from at least one nonfunctionalized thermoplastic polyolefin and at least one functionalized thermoplastic polyolefin, depending on the composition desired for surface layer A.

The at least one nonfunctionalized thermoplastic polyolefin for use in

thermoplastic adhesive layer A2 described herein does not comprise carboxyl functional groups (acid or anhydride groups), epoxy functional groups, or other functional groups as known in the art, either directly copolymerized in the polyolefin backbone or grafted onto the backbone. The one or more nonfunctionalized thermoplastic polyolefins may be used in combination with the one or more functionalized thermoplastic polyolefins. Preferably, the one or more nonfunctionalized thermoplastic polyolefins are selected from

polyethylenes, polypropylenes, ethylene alpha-olefin copolymers, ethylene propylene diene rubbers (EPDM), polystyrene, and mixtures thereof. The one or more

nonfunctionalized thermoplastic polyolefins preferably have a melting point ranging from about 80 to 200 °C.

Depending on the end use and physical properties desired, the one or more nonfunctionalized thermoplastic polyolefins may be present in thermoplastic adhesive layer A2 in an amount from at or about 25 to at or about 75 weight percent and more preferably from at or about 30 to at or about 70 weight percent, the weight percentages being based on the total weight of the nonfunctionalized thermoplastic polyolefins and functionalized thermoplastic polyolefins comprising thermoplastic adhesive layer A2.

If a polypropylene homopolymer is used as a nonfunctionalized thermoplastic polyolefin, it cannot be the only nonfunctionalized thermoplastic polyolefin present in adhesive layer A2. When adhesive layer A2 comprises a polypropylene homopolymer as a nonfunctionalized thermoplastic polyolefin, adhesive layer A2 should also comprise at least 20 weight percent, based on the total weight of nonfunctionalized thermoplastic polyolefin, of an ethylene and/or propylene copolymer or one or more EPDM polymers as an additional nonfunctionalized thermoplastic polyolefin. For example, a

nonfunctionalized thermoplastic polyolefin as used herein may comprise 80 weight percent polypropylene homopolymer and 20 weight percent of an ethylene and/or propylene copolymer. Examples of ethylene and/or propylene copolymers include ethylene alpha-olefin copolymers, polystyrene, and mixtures thereof. Examples of ethylene alpha-olefin copolymers include ethylene-butene, ethylene-propylene, ethylene- octene copolymers. EPDM polymers may also be used in combination with

polypropylene homopolymers.

The at least one functionalized thermoplastic polyolefin used in thermoplastic adhesive layer A2 may be any polymer which comprises a carboxyl functional group. Preferably, the one or more functionalized thermoplastic polyolefins are one or more polyolefins which have been grafted with a carboxyl functional group. The grafting agents, i.e. the at least one monomer having at least one carboxyl functional group, is preferably present in the one or more functionalized thermoplastic polyolefins in an amount from at or about 0.05 to at or about 6 weight percent, preferably from at or about 0.1 to at or about 2.0 weight percent, the weight percentages being based of the total weight of all monomers used to prepare the functionalized thermoplastic polyolefin. Stated alternatively, the weight percentages of the grafted comonomer are based on the total weight of the grafted copolymer.

As defined and used herein, the at least one functionalized thermoplastic polyolefin does not comprise an epoxy containing material or functional group. Although an epoxy containing material may be used in adhesive layer A2, it is different than the at least one functionalized thermoplastic polyolefin. It is preferred that when a

functionalized thermoplastic polyolefin is present in adhesive layer A2, that epoxy containing materials are not present in adhesive layer A2.

Preferably, the at least one functionalized thermoplastic polyolefin comprises acid groups, anhydride groups, or a combination of acid and anhydride groups. Preferred examples of monomers which may be used to prepare said functionalized polyolefins includes ethylene, propylene, butene, octene, maleic anhydride, maleic acid,

isopropylene, styrene, acrylates, methacrylates, alkylacrylates, and combinations of two or more of these.

Functionalized thermoplastic polyolefins are preferably derived by grafting at least one monomer having at least one carboxyl functional group to a polyolefin including ethylene alpha-olefins or copolymers derived from at least one alpha-olefin and a diene. Preferably, thermoplastic adhesive layer A2 described herein comprises functionalized thermoplastic polyolefins selected from grafted polyethylenes, grafted polypropylenes, grafted ethylene alpha-olefin copolymers, grafted copolymers derived from at least one alpha-olefin and a diene and mixtures thereof. More preferably, thermoplastic adhesive layer A2 described herein comprises maleic anhydride grafted polyolefins selected from maleic anhydride grafted polyethylenes, maleic anhydride grafted polypropylenes, maleic anhydride grafted ethylene alpha-olefin copolymers, maleic anhydride grafted copolymers derived from at least one alpha-olefin and a diene and mixtures thereof.

Polyethylenes used for preparing maleic anhydride grafted polyethylene (MAH-g- PE) are commonly available polyethylene polymers selected from HDPE (density higher than 0.94 g/cm³), LLDPE (density of 0.915 - 0.925 g/cm³) or LDPE (density of 0.91 - 0.94 g/cm³). However, for applications where overmolded polymer-metal hybrid support beams are used in high temperature applications where temperatures can reach up to 85°C, it is preferred that high density polyethylene homopolymers are not used to prepare the functionalized thermoplastic polyolefin. Polypropylenes used for preparing maleic anhydride grafted polypropylene (MAH-g-PP) are commonly available copolymer or homopolymer polypropylene polymers.

Ethylene alpha-olefins copolymers comprise ethylene and one or more alpha- olefins, preferably the one or more alpha-olefins have 3-12 carbon atoms. Examples of alpha-olefins include but are not limited to propylene, 1 -butene, l-pentene, 1 -hexene- 1, 4-methyl l-pentene, l-heptene, l-octene, l-nonene, l-decene, l-undecene and 1- dodecene. Preferably the ethylene alpha-olefin copolymer comprises from at or about 20 to at or about 96 weight percent of ethylene and more preferably from at or about 25 to at or about 85 weight percent; and from at or about 4 to at or about 80 weight percent of the one or more alpha-olefins and more preferably from at or about 15 to at or about 75 weight percent, the weight percentages being based on the total weight of the ethylene alpha-olefins copolymers. Preferred ethylene alpha-olefins copolymers are ethylene- propylene copolymers, ethylene-butene copolymers, and ethylene-octene copolymers.

Copolymers derived from at least one alpha-olefin and a diene are preferably derived from alpha-olefins having preferably 3-8 carbon atoms. Preferred copolymers derived from at least one alpha-olefin and a diene are ethylene propylene diene elastomers. The term“ethylene propylene diene elastomers (EPDM)” refers to any elastomer that is a terpolymer of ethylene, at least one alpha-olefin, and a

copolymerizable non-conjugated diene such as norbornadiene, 5-ethylidene-2- norbomene, dicyclopentadiene, l,4-hexadiene and the like. When a functionalized ethylene propylene diene elastomer is used in thermoplastic adhesive layer A2 described herein, the ethylene propylene diene polymer preferably comprises from at or about 50 to at or about 80 weight percent of ethylene, from at or about 10 to at or about 50 weight percent of propylene and from at or about 0.5 to at or about 10 weight percent of at least one diene, the weight percentages being based on the total weight of the ethylene propylene diene elastomer.

The one or more functionalized thermoplastic polyolefins may be present in thermoplastic adhesive layer A2 in an amount from at or about 25 to at or 75 weight percent and more preferably from at or about 30 to at or about 75 weight percent, the weight percentages being based on the total weight of the nonfunctionalized thermoplastic polyolefins and functionalized thermoplastic polyolefins used in thermoplastic adhesive layer A2.

The amount of the at least one monomer having at least one carboxyl functional group used in the manufacture of the functionalized polyolefins, in combination with the concentration of the functionalized polyolefm(s) in thermoplastic adhesive layer A2, determines the total carboxyl functional groups present in thermoplastic adhesive layer A2. It is desirable that the total carboxyl functional groups present in thermoplastic adhesive layer A2 ranges from about 0.02 to 1.5 weight percent, preferably from 0.05 to 1.0 weight percent, and more preferably from 0.05 to 0.75 weight percent, even more preferably from 0.05 to 0.55 weight percent, and most preferably from 0.05 to 0.20 weight percent based on the total weight of functionalized thermoplastic polyolefin and nonfunctionalized thermoplastic polyolefin in thermoplastic adhesive layer A2.

The melting points of nonfunctionalized thermoplastic polyolefins and functionalized thermoplastic polyolefins, when present in thermoplastic adhesive layer A2, should be less than the melting point of the composition of surface layer Al. Preferably, the melting point of thermoplastic adhesive layer A2 should be at least 10 °C, preferably at least 20 °C, and more preferably at least 25 °C below the melting point of the composition of surface layer Al. It is understood that the melting point of

thermoplastic adhesive layer A2 refers to the melting point of the highest-melting polymer that is present in thermoplastic adhesive layer A2.

Adhesive layer A2 used in surface layer A may also be prepared from an epoxy containing material or mixture of two or more epoxy containing materials when the overmolding polymer C is a polyamide and surface layer Al is a polyamide. Such epoxy- containing layers may be thermoset rather than thermoplastic materials, depending on whether and to what extent the epoxy containing material is crosslinked. Suitable epoxy containing materials for use in adhesive layer A2 include any epoxy component capable of reacting with free amine and/or acid end groups of polyamide resins and having at least one epoxy functional group per molecule of epoxy component. U.S. Pat. No.

6,974,846 and U.S. Pat. No. 7,008,983 disclose epoxy components that may be reacted with polyamides.

A preferred epoxy component is at least one diphenolic epoxy condensation polymer, which is known in the art, and includes condensation polymers of

epichlorohydrin with a diphenolic compound. Also preferred is a 2, 2-bis(p-glycidyl) (oxyphenyl) propane condensation product with 2,2-bis(p-hydroxyphenyl)propane and similar isomers. Commercially available diphenolic epoxy condensation polymers include the EPON® 800 resin series, from Momentive Specialty Chemicals.

Preferred epoxy components comprise at least one epoxy functional group, but may comprise two or more epoxy functional groups per molecule of the epoxy component. The epoxy component should comprise not more than about 16, preferably not more than 10, and even more preferably not more than 6 epoxy functional groups per molecule of epoxy component.

The epoxy groups of the epoxy component preferably comprise glycidyl ethers, and even more preferably, glycidyl ethers of phenolic compounds. The epoxy components may be polymeric, oligomeric, or non-polymeric. An example of an epoxy component is a tetraglycidyl ether of tetra (parahydroxyphenyl) ethane. An example of a commercially available epoxy component is Araldite® ECN 1299, available from

Advanced Materials, Basel Switzerland. Additional examples are EPON® 832 and 828 available from Momentive Specialty Chemicals, Inc.

Other epoxy components may include epoxidized natural oils or fatty esters such as epoxidized soybean oil, epoxidized linseed/soybean oil, copolymers of styrene and glycidyl methacrylate, diglycidyl ethers of bisphenol A / bisphenol F, diglycidyl adducts of amines and amides, diglycidyl adducts of carboxylic acids, bis(3,4- epoxycyclohexylmethyl) adipate, vinylcyclohexene di-epoxide, epoxy phenol novolac and epoxy cresol novolac resins, epoxidized alkenes such as epoxidized alpha olefins, and epoxidized unsaturated fatty acids.

When an epoxy component is used as a component of adhesive layer A2, the epoxy component may comprise additional materials such as curing agents and/or catalysts to improve the curing rate of the epoxy component. Examples of epoxy curing agents, secondary curing agents, and catalysts include, without limitation, aliphatic amines, cycloaliphatic amines, polyamides, amidoamines, aromatic amines and anhydrides. Additional examples of these materials are described in ThreeBond

Technical News, December 1990, available at https://www.threebond.co.ip/en/technical/technicalnews/pdf/tech32.pdf. last accessed on October 4, 2019.

Adhesive layer A2 may also comprise one or more rheology modifiers, heat stabilizers, colorants, antioxidants, lubricants, fillers, and other additives as adjuncts so long as the additives do not adversely affect the properties of the overmolding polymer or the resulting overmolded PMH support beams. It is preferred that the total concentration of these additives not exceed 50 wt%, more preferably that it not exceed 20 wt% of the total weight of all ingredients in adhesive layer A2. With the exception of fillers, it is preferred that the total weight of each individual additive not exceed 5 wt%, more preferably that it not exceed 3 wt% or 1 wt% of the total weight of all ingredients in adhesive layer A2. The additive(s) may be added to adhesive layer A2 by any means known in the art, such as melt-mixing, for example.

The thickness of adhesive layer A2 may range from about 0.25 mil (0.00025 inch, 0.00635 mm) to 10 mil (0.010 inch, 0.254 mm), or from about 1 mil (0.001 inch, 0.0254 mm) to about 10 mil, preferably from about 1 mil to about 5 mil (0.005 inch,

0.127 mm). Thicknesses below about 0.5 mil (0.0005 inch, 0.0127 mm) or below about 1 mil may result in lower bond strengths between the metal and overmolded polymer, and at thicknesses greater than 5 mil there is limited benefit to improvement in bond strength.

Adhesive layer A2 may be applied to part of all of the surface of a metal sheet or metal surface which may be used to prepare PMH support beams by any means known in the art including spraying, dipping, rolling, or applied as a single or multilayer film. Adhesive layer A2 may also be applied to an already prepared support beam. When an epoxy material is used as adhesive layer A2, the concentration of adhesive layer A2 applied to the metal surface ranges from about 0.5 to about 5 ml/sq. ft. of metal surface. Preferably, the concentration ranging from about 0.5 to about 3 ml/sq. ft., more preferably about 0.75 to about 2 ml/sq. ft. This concentration is based on undiluted adhesive layer A2. In other words, the materials comprising an epoxy component used in to make adhesive layer A2 do not comprise any solvents. Alternatively, the materials comprising an epoxy component used to prepare adhesive layer A2 may be dissolved in a solvent and applied to metal layer B as a solvent solution or dispersion. If a solvent is used, the concentration of the materials comprising an epoxy component remaining on the surface of metal layer B should be about 0.5 to about 5 ml/sq. ft. of metal surface after removal or evaporation of the solvent. Although such ranges are not expressly set forth herein, all possible concentration ranges of adhesive layer A2 having endpoints between about 0.5 and about 5 ml/sq. ft., inclusive, are contemplated for use in these layers.

It is preferred, when adhesive layer A2 comprises an epoxy component, that surface layer Al comprise an aliphatic polyamide, semiaromatic polyamide, or a combination of two or more of these. Examples of aliphatic polyamides include those selected from the group consisting of poly(hexamethylene adipamide) (PA66), polycaprolactone (PA6), poly(tetramethylene hexanedi amide) (PA46), PA6/66, PA610,

PA612, and blends thereof. Specific examples of polyamide blends include any of the foregoing aliphatic polyamides, especially blends of PA6 with PA66 and PA610 or PA612. The weight ratio of polyamides in blends of PA6/PA66/PA610 or

PA6/PA66/PA612 may range from about 30 to 50(PA6)/20 to 50(PA66)/l0 to 40 (PA610 or PA612) weight percent respectively in which the total of the weight percentages of the three polyamides is 100 weight percent. Examples of semiaromatic polyamides include PA610/6T, PA612/6T, and PA66/6T. Additionally, when an aliphatic polyamide or blend of aliphatic polyamides are used for surface layer Al in combination with an epoxy layer A2, surface layer Al may be a laminate comprising one film layer of an aliphatic polyamide or blend of aliphatic polyamides with a second film layer of a semiaromatic polyamide such as PA610/6T or PA612/6T. In other words, surface layer Al may comprise a bilayer film. Such laminates can be prepared by a belt laminator or by co- extrusion, for example. When such laminates are used, it is preferred that surface layer Al be in direct contact with adhesive layer A2. If multiple surface layers Al are used, it is preferred that the outermost layer have good environmental barrier properties, such as protecting adhesive layer A2 from moisture, salt, corrosion, ETV light exposure, heat aging, and the like to prevent degradation of the adhesive bond strength between layer Al and the metal substrate B.

Metal Support Beam B

Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to Figure 1, an example of a metal support beam B 10 is depicted. Metal support beam B 10 may be prepared from any metal which has sufficient adhesion to adhesive layer A2 such that the resulting overmolded PMH support beam exhibits the desired combination of properties. Preferably, the metal is selected from aluminum, titanium, steel, for example carbon steel or stainless steel, brass, copper, magnesium, and metal alloys. More preferably, the metal is aluminum or zinc-coated (galvanized) steel.

The metal used to prepare PMH support beams as used herein may be used as received from the supplier or the metal may be cleaned to remove contaminants and oil residue from the metal surface. Examples of methods to clean the metal surface include washing the surface of the metal with water/surfactant and rinsing the metal to remove residual surfactant, or cleaning the metal with acetone and drying the metal surface. The metal surface may also be treated with plasma to remove contaminants and residual oils.

The metal used to prepare PMH support beams can be any shape. The shape of the metal is limited only by the ability to roll or form the metal into a metal support beam B 10. Preferably the metal used to prepare metal support beams B 10 is in the shape of a metal sheet. Metal support beams B 10 formed from metal sheets preferably have a circular, oval, rectangular, square, or trapezoidal cross-sectional shape. Such metal support beams B 10 may be used to prepare PMH support beams for use as cross-beams in automobiles, trucks, and other vehicles used for transportation. These PMH support beams may be completely hollow from one end to the opposite end of the beam or the beam may comprise hollow sections, solid sections, or both hollow and solid sections.

The PMH support beams prepared from these metal sheets are closed metal support beams meaning that the surface of the PMH support beam is continuous around the outer circumference of the PMH support beam except for any holes or openings desired on the surface of the metal support beam B 10. Figure 1 shows a metal support beam B 10 having an opening 11 and a hole 12 which may be overmolded with overmolding polymer C.

These PMH support beams may be pinched or closed off at one or both ends of the beam. These pinched off ends can be designed to comprise attachment points. These attachment points (such as threaded bolt holes) may act as location points for attaching the tube or beam to automotive components such as A-pillars, dashboards, firewalls, and other parts. Such an attachment provides a rigid connection to the automobile or other part. Other attachment methods may also be contemplated such as the use of adhesives, clamps, and welding.

The thickness of metal sheets which may be used to form PMH support beams typically range from about 0.254 mm to about 6.35 mm. Metal sheet thicknesses above about 6.35 mm may be used, but the weight advantage of using the metal support beams described herein is diminished as the thickness of the metal increases. Preferably, the metal sheets have a thickness ranging from about 0.05 mm to 7 mm, from about 0.5 mm to 5 mm, from about 0.30 mm to 6.35 mm, and more preferably from 0.30 to 5 mm or from about 1 mm to 3 mm.

Process for Making PMH Support Beams

Metal substrates used to prepare PMH support beams may be purchased as a sheet of metal having a thickness ranging from about 0.002 to 0.250 inches (0.05 mm to 6.35 mm) and optionally cleaned or treated, as described above.

PMH support beams as described herein may be prepared by methods known in the art but are preferably prepared from metal sheets in which surface layer A is adhered to one or both sides of the metal sheet by laminating, bonding, or other means of adhering the materials together. Surface layer A may be adhered to metal sheets by typical means. For example, surface layer A may first be prepared by forming films of adhesive layer A2 and surface layer Al and bonding or laminating films Al and A2 together to form surface layer A comprising a bilayer film of Al and A2. Alternatively, thermoplastic adhesive layer A2 and polymer Al may be extruded, cast or blown together to directly form a bilayer film. This bilayer film may then be adhered to one or both surfaces of a metal sheet by commonly used methods such as lamination or pressing. During lamination, the layers are heated and pressed together using rollers, platens or other means to apply pressure to the various layers to form a metal sheet coated with surface layer A.

Alternatively, adhesive layer A2 may be coated onto the metal surface by methods commonly used in the art, such as spraying, dipping, extrusion, film application, or the like. Surface layer Al may then be adhered to adhesive layer A2 to provide a metal sheet comprising surface layer(s) A. The resulting metal sheet may have surface layer A directly attached to a portion of one surface or a portion of both surfaces or attached to all of one surface or to all of both surfaces of the metal sheet. These metal sheets comprising surface layer A may be overmolded as prepared, but are preferably formed into tubes or beams, specifically metal support beams B 10 having partially or completely open or hollow interiors or centers.

These metal support beams B 10 can be overmolded with polymer C to provide overmolded metal support beams. These coated metal sheets may be rolled or formed into hollow metal support beams B 10 of various sizes and shapes depending on the end use application. Such processes for shaping metal sheets are well known in the art.

Alternatively, PMH support beams may be formed from uncoated metal sheets.

These uncoated metal support beams B 10 may then be coated with adhesive layer A2 followed by coating adhesive A2 with polymer layer Al to form surface layer A.

Examples of coating processes include spraying, dipping, and rolling. Essentially any process may be used to apply surface layer A onto the metal surface of metal support beams B 10 and are easily within the skill of one in the art.

Referring now to Figure 2, a cross-sectional view of a PMH support beam 20 includes a metal support beam B 10, surface layers Al (22 and 24) and adhesive layers A2 (21 and 23) on both sides of metal layer B 10 is depicted.

When a PMH support beam 20 is produced from a metal support beams B 10 having openings 11 and holes 12 in its surfaces, the PMH support beam 20 will have corresponding openings and holes on its surface. When such PMH support beams 20 are overmolded, overmolding polymer C may be molded into these openings and/or holes as well as onto the exterior surface of the PMH support beams 20 resulting in an

overmolded tube or beam comprising the overmolded part. An advantage of this overmolding technique is that the overmolded part is adhered to the PMH support beam 20 by the combined adhesion of surface layer A to overmolding polymer C as well as by mechanical interlocking from the overmolded part being molded into holes 12 in the metal support beam B 10.

An advantage of PMH support beams 20 described herein, is that surface layer A may be present on both the internal and external surfaces of the metal support beam B 10. Overmolding of such beams B 10 provides maximum contact of surface layer A with overmolding polymer C to provide optimized adhesion properties. If the PMH support beam 20 has surface layer A on a portion or all of both the internal and exterior surfaces, the overall bonding strength of the overmolded part to the PMH support beam 20 is increased relative to PMH support beams which do not comprise surface layer A on internal surfaces of the PMH support beam.

Examples of overmolded PMH support beams include automotive components such as front end modules, lift-gates, and cross car beams.

Overmolding Polymer C

Overmolding polymer C which may be overmolded onto PMH support beams 20 described herein to provide overmolded PMH support beams is selected from

polyamides, polypropylenes, or combinations of one or more polypropylenes with one or more polyamides, depending on the polymers used as layer Al of surface layer A. It is preferred, though not required, that the same species of polymer be used for both surface layer Al and overmolding polymer C. Stated alternatively, if layer Al of surface layer A comprises at least one polyamide, then the overmolding polymer preferably comprises at least one polyamide. If layer Al of surface layer A comprises at least one polypropylene- based polymer, then the overmolding polymer preferably comprises at least one polypropylene-based polymer.

It is also desirable that surface layer Al have a lower melting point and lower heat of fusion than overmolding polymer C.

Overmolding polymer C may additionally comprise reinforcing agents for improving mechanical strength and other properties, which may be a fibrous, tabular, powdery or granular material and may include glass fibers, carbon fibers including PAN- derived or pitch-derived carbon fibers, gypsum fibers, ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, rock wool, powdery, granular or tabular reinforcing agents such as mica, talc, kaolin, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay,

wollastonite, montmorillonite, titanium oxide, zinc oxide, and graphite. Two or more reinforcing agents may be combined in these compositions; and although every combination is not expressly set forth herein, the overmolding compositions may include any combination of two or more of the reinforcing agents described herein. Glass fibers, carbon fibers, glass flakes, glass beads, mica, and combinations of these are preferred. Suitable glass fibers may be chopped strands of long or short glass fibers, and milled fibers of these.

The reinforcing agent may be sized or unsized. The reinforcing agent may be processed on its surface with any known coupling agent (e.g., silane coupling agent, titanate coupling agent) or with any other surface-treating agent. The reinforcing agent for use herein may be coated.

If fibers are used as the reinforcing agent, the fibers may have a circular or non circular cross section. A fiber having a non-circular cross section refers to a fiber having a major axis lying perpendicular to a longitudinal direction of the fiber and corresponding to the longest linear distance in the cross section. The non-circular cross section has a minor axis corresponding to the longest linear distance in the cross section in a direction perpendicular to the major axis. The non-circular cross section of the fiber may have a variety of shapes including a cocoon-type (figure- eight) shape; a rectangular shape; an elliptical shape; a semielliptical shape; a roughly triangular shape; a polygonal shape; and an oblong shape. As will be understood by those skilled in the art, the cross section may have other shapes. The ratio of the length of the major axis to that of the minor access is preferably between about 1.5: 1 and about 6: 1. The ratio is more preferably between about 2: 1 and 5 : 1 and yet more preferably between about 3 : 1 to about 4: 1. The fiber may be long fibers, chopped strands, milled short fibers, or other suitable forms known to those skilled in the art.

If used in combination with overmolding polymer C, the reinforcing agent ranges from about 10 to about 70 weight percent, preferably about 15 to about 60 weight percent, and more preferably about 15 to about 55 weight percent based on the sum of the total weight of all ingredients in overmolding polymer composition C. Although the ranges are not expressly set forth herein, all ranges of the amount of reinforcing agent between 10 and 70 weight percent, inclusive, based on the total weight of the

composition of the overmolding polymer C, are contemplated for use in the overmolding polymer C.

Overmolding polymer composition C may also comprise one or more additives, such as, for example, rheology modifiers, heat stabilizers, colorants, antioxidants, lubricants, fillers, and other additives as adjuncts so long as the additives do not adversely affect the properties of the overmolding polymer or the resulting overmolded PMH support beams. It is preferred that the concentration these additives not exceed 5 wt percent of the total weight of polymer composition C. Nonlimiting examples of filler materials include talc, wollastonite, calcium oxide, siloxane, calcium carbonate, mica, calcinated clay, kaolin, magnesium sulfate, magnesium silicate, barium sulphate, titanium dioxide, sodium aluminum carbonate, barium ferrite, and potassium titanate. The additives and reinforcing agents described herein may be added to overmolding polymer C by any means known in the art, such as, for example, melt-mixing.

Preferably, when one or more fillers or reinforcing agents are present in overmolding polymer C, overmolding polymer C may also comprise functionalized materials such as those used in thermoplastic adhesive layer A2, at levels of from 1 to 30 wt%, based on the total weight of the composition of overmolding polymer C, generally to ensure bonding between the polymer(s) of overmolding composition C and the filler(s) or reinforcing agent(s).

When overmolded onto PMH support beams, the molds used during the overmolding process may be designed to overmold a specific shaped part onto the PMH support beams. Examples of such shaped parts when the PMH support beams are cross- beams for automobiles or trucks include steering-column retainer, link elements, airbag housing retainer, air duct retainer, ventilation outlets, glovebox retainer, air-conditioning equipment retainer, multimedia equipment retainer, instrument display retainer, instrument panel connectors, connector for bulkhead or firewall, center console struts, A- columns, and cable/electrical harness connectors.

Process for Making Overmolded Polymer Metal Hybrid Support Beams

PMH support beams 20 may be overmolded with overmolding polymer composition C to provide overmolded PMH support beams having an overmolded part of a specific shape or design. A process to prepare overmolded PMH support beams described herein comprises the steps of:

a) placing a polymer-metal hybrid support beam 20 into a heated mold on a molding machine with surface layer A facing outward; b) closing the heated mold and further heating the polymer-metal hybrid support beam 20 to at least the T_g of surface layer A;

c) injecting into the heated mold overmolding polymer composition C onto surface layer A of the polymer-metal hybrid support beam 20 to provide an overmolded polymer-metal hybrid support beam in which 90 percent or less of the exterior surface of polymer-metal hybrid support beam is overmolded;

d) allowing the overmolded polymer-metal hybrid support beam to cool and solidify; e) opening the mold and removing the overmolded polymer-metal hybrid support beam.

The entire surface of the PMH support beam 20 or a portion of the surface of the PMH support beam 20 may be overmolded. For designs in which only a portion of the surface will be overmolded, the mold may be tailored such that a portion of its interior surface is in direct contact with the complementary portion of surface layer C, that is, the portion of the PMH support beam 20 that is not to be overmolded. This direct contact is such that molten overmolding polymer C is prevented or substantially prevented from interposition between surface layer A and the mold’s interior surface. In this

configuration, at least a portion of surface layer A is in direct contact with the interior surface of the mold. As described above, the mold may be heated to a temperature at least equal to the Tg of the polymers in the surface layer A. In the absence of surface layer A, adhesive layer Al may cure in lamination and therefore it will not bond to overmolding polymer C. Alternatively, the wet epoxy coating or thermoplastic adhesive of layer Al may be removed from metal layer B by high pressure flow of polymer C in the overmolding process. In either case, in the absence of surface layer A, the interior of the mold is likely to be contaminated by residual cured epoxy or other material originating from adhesive layer Al.

Accordingly, an advantage of overmolded PMH support beams described herein is that during manufacture of the overmolded polymer-metal hybrid support beam, at least 50 overmolded PMH support beams can be consecutively produced on the same molding machine without the surface of the mold cavity becoming contaminated with measurable amounts of contaminants from the PMH support beam 20 Specifically, after 50 repetitions of steps (a) to (e) the total mold deposits are 0.25 grams or less per square inch of mold surface which is in contact with surface layer A when the mold is closed.

An alternative way of describing this advantage of the PMH support beams 20 described herein is that after 50 repetitions of steps (a) to (e), total mold deposits are 50 percent less, preferably 90 percent less, than the total mold deposits of an identical process using a PMH support beam lacking surface layer Al .

Referring now to Figure 3, a PMH support beam 20 is depicted, which has been overmolded to form overmolded PMH support beam 30. Overmolded portion 31 is shown in shape of an I-beam. During overmolding, overmolding polymer C is molded into the opening 11 in PMH support beam 20 leaving slots 32. These slots 32 are a result of stops or“shut offs” in the mold being placed on each side of the opening 11 to prevent the overmolding polymer C from flowing into the remaining hollow parts of the PMH support beam 20.

Referring now to Figure 3 A, a cross-sectional view of the overmolded PMH support beam 30 shows how the overmolded polymer C is molded both inside and around the outside of the PMH support beam 20 simultaneously to form an overmolded portion 31 which is in direct contact with surface layer A (22 and 24) on both the interior and exterior of PMH support beam 20. Figure 3 A also shows polymer filling 34 in optional holes 12 in PMH support beam 20. During overmolding, the overmolding polymer C flows into holes 12 to provide mechanical interlocking of overmolded portion 31 with PMH support beam 20.

Referring now to Figure 4, an example of an insert 40 is depicted. Recessed areas 41 in the edge of the insert 40 form ribs 42. Figure 4A shows insert 40 placed into PMH support beam 20. The surface area of the ribs 42 is flush against the inner surface of PMH support beam 20. Figure 4B shows PMH support beam 20, comprising insert 40, which has been overmolded to form overmolded part 30 wherein overmolding occurs diametrically opposite the location of the insert 40. The term“diametrically opposite”, as used herein, refers to a location on the exterior surface of the PMH support beam 20 that is determined by the shortest distance between the interior and exterior surfaces of the PMH support beam 20 at the point or points where the insert 40 or the rib 42 is in direct contact with the interior surface of the PMH support beam 20. Still referring to Figure 4B, overmolding the PMH support beams 20 described herein is typically conducted at very high pressures (typically about 7 MPa to 200 MPa) which can cause the PMH support beam or tube 20 to deform or collapse. Such deformations are undesirable in that they weaken the beams or tubes 20 and reduce the ability of the beams or tubes 20 to resist external forces without breaking. One method of preventing the PMH support beams or tubes 20 from undergoing significant deformation during overmolding is to have an insert 40 inside the beam or tube 20 which provides support to the beam or tube 20 at the location where overmolding polymer C is overmolded onto the surface(s) of the tube or beam 20. Preferably, the insert 40 is wider than the diametrically opposite surface area of the high pressure overmolding polymer C that forms overmolded portion 31 of overmolded PMH article 30.

Further depicted in Figure 4B are members 43. Members 43 may be ribs on the planar surface of insert 40. Such ribs may provide further reinforcement to the structure of insert 40 so that it will better withstand the overmolding forces. Alternatively, member 43 may be a pass-through internal to insert 40, so that when the entrance 44 of the pass-through member 43 is aligned with holes 12 (not depicted in Figure 4B) in the PMH support beam 20, the overmolding polymer fills the pass-through member 43, and the insert 40 becomes an integral part of the overmolded PMH article 30.

The inserts can be any material capable of providing support to the tube or beam to prevent the beam or tube from deforming during overmolding. Preferably, the inserts comprise glass reinforced polymers such as polyamides or polypropylene. To minimize weight, the inserts typically comprise at least one rib (member 43, for example) along the length of the insert. These inserts are placed or inserted into the tube or beam such that the insert(s) are in direct contact with the internal surface of the tube or beam at the precise location where overmolding polymer C is overmolded onto the opposing exterior surface location of the beam. Such a design allows a metal support beam to be overmolded without causing the beam or tube to significantly deform or collapse under the overmolding pressures and also allows for the use of a lightweight beam or tube.

The use of such inserts minimizes any deformations in the PMH support beams such that PMH support beams which use said inserts exhibit at least 95 percent the flexural strength of an identical PMH support beam before overmolding. The inserts may be held in place by methods known in the art. Such methods may be permanent or reversible, that is, the insert may remain attached the overmolded PMH article, or the insert may be removable from the overmolded PMH article. For example, depressions or slight indentation on the interior surface of the metal support beam B 10 may be used to allow for correct placement of the insert in the metal support beam.

Alternatively, rods having measurement markings may be used to place the insert into the metal support beam B 10 at a given position inside the metal support beam B 10. The inserts may be held in place by using an adhesive applied to the surface of the insert just before insertion. The inserts may also be held in place by using an interference or compression fit, which may allow the insert to be more easily removed from the article. Overmolded Polymer Metal Hybrid Support Beams

Overmolded polymer-metal hybrid support beams described herein have improved retention of physical properties such as flexural modulus and lap shear after exposure to various environmental conditions compared to identical overmolded polymer-metal hybrid support beams but which do not comprise a specific surface layer A. One advantage of overmolded polymer-metal hybrid support beams described herein is that the overmolding process allows for the introduction of lightweight cross-supports or other structural elements to the polymer-metal hybrid support beams. However, if thermoplastic adhesive layer A2 has insufficient adhesion properties to either surface layer Al or metal layer B, then the resulting overmolded polymer-metal hybrid support beams may exhibit undesirable or inferior properties such as insufficient flexural modulus or lap shear both initially and after environmental exposure.

Because of the difficulty in being able to accurately test polymer metal hybrid support beams for adhesion and lap shear properties, metal test coupons, for example aluminum test coupons, are used in place of the support beam to determine physical property advantages of the adhesive systems used to prepare the PMH support beams.

The combination of specific surface layers A with the polymer metal hybrid support beams described herein, provides PMH support beams which exhibit a desirable combination of properties.

Overmolded test samples prepared from aluminum coupons, which represent, for test purposes, overmolded polymer metal hybrid support beams described herein, in which the overmolding polymer is a polyamide, exhibit an initial lap shear which is at least 10 percent, preferably at least 20, more preferably at least 25, and most preferably at least 40 percent greater than an identical test sample, tested under identical conditions, but which does not comprise surface layer Al when measured according to ASTM D3163, which is described in detail in the Examples, below.

Additionally, overmolded polymer-metal hybrid support beams described herein also exhibit an initial flexural modulus which is at least 10 percent greater than an identical overmolded polymer-metal hybrid article, tested under identical conditions, but which does not comprise surface layer Al or adhesive layer A2 when measured according to ISO 178 when mechanically interlocked test samples are used.

The overmolded polymer-metal hybrid articles described herein, when heat cycled from minus 35 to plus 85 °C for 40 cycles, exhibit an improvement in lap shear of at least 10 percent compared to an identical overmolded polymer-metal hybrid article, tested under identical conditions, but which does not comprise surface layer Al when measured according to ASTM D3163.

The overmolded polymer-metal hybrid articles described herein, when exposed to 70 % relative humidity and 60 °C for 1000 hours, exhibits an improvement in lap shear of at least 10 percent compared to an identical overmolded polymer-metal hybrid article, tested under identical conditions, but which does not comprise surface layer Al when measured according to ASTM D3163.

Overmolded PMH support beams described herein unexpectedly exhibit a combination of initial adhesion, high temperature adhesion, moisture resistance, and thermal stability properties which are not obtainable with typical adhesive systems used to bond metals to overmolded polymer compositions. Overmolded PMH support beams described herein exhibit an initial adhesion or initial lap shear of at least 11.5 MPa when measured at 23 °C, a high temperature adhesion or high temperature lap shear of at least

5.5 MPa when measured at 85 °C, a moisture resistance as measured by a lap shear after 1000 hrs. humidity testing at 70 % relative humidity (RH) and 60 °C of at least 9.0 MPa when measured at 23 °C, and a thermal stability as measured by a lap shear of at least

11.5 MPa after 40 thermal cycles from minus 35 °C to plus 85 °C when measured at 23 °C, and wherein all lap shear values were determined according to ASTM D3163. Unexpectedly, when overmolded polymer-hybrid articles described herein are exposed to elevated temperature testing or humidity testing as described herein, the exposed overmolded polymer-hybrid articles show an unexpected improvement in lap shear of at least 10, preferably at least 20, more preferably at least 25, and most preferably at least 50 percent greater than overmolded polymer-hybrid articles which are identical in shape and composition and which have been exposed to identical heat cycling or humidity testing, but which do not comprise surface layer Al.

The following examples are provided to describe the invention in further detail. These examples, which set forth a preferred mode presently contemplated for carrying out the invention, are intended to illustrate and not to limit the invention.

EXAMPLES

The following examples show adhesion values obtained when specific

combinations of surface layer Al and thermoplastic adhesive layer A2 are used as surface layer A. Surface layers A, comprising surface layer Al and thermoplastic adhesive layer A2, may be used to prepare overmolded polymer-metal hybrid support beams as described herein. The PMH articles described herein are identified by Έ” in the tables below, and comparative examples are identified in the tables below by“C”.

Materials

In the compounds, processes, and articles exemplified in the tables below, the following materials were used. All percent values are by weight unless indicated otherwise.

AL1 : a maleic anhydride grafted polyethylene thermoplastic adhesive commercially available from The Dow Chemical Company of Midland MI as Bynel 41E755 Adhesive Resin

AL2: a maleic anhydride grafted polypropylene thermoplastic adhesive available commercially from The Dow Chemical Company of Midland MI as Bynel 50E739 Adhesive Resin. Melt point of 142 C, MFR of 6.0 g/lOmin (230C/2. l6kg), Density of 0.89, as reported by manufacturer.

AL3: an epoxy difunctional bisphenol A resin available from Hexion, Inc., of Columbus, OH, containing 185-192 g/eq weight, based on equivalents of epoxide moieties, as measured by ASTM D1652 (as stated in manufacturer's technical data sheet). SL1 : a poly(hexamethylene terephthalamide/hexamethylene decanediamide) (PA610/6T (80:20 molar ratio) having a melt point of 2l4°C

SL2: a PA6 having a melt point of 220°C, a density of 1.12 g/cc and a relative viscosity of 3.89-4.17 (as per ISO 307)

SL3 : a PA6,6 having a melt point of 189°C, a density of 1.12 g/cm³ and a relative viscosity of 3.89-4.17 (as per ISO 307)

SL4: an ethylene-butene copolymer having a melt point of l66°C, a density of 0.90 g/cc and a MI of 0.45 g/lOmin (l90°C/2.16 kg) available from Lyondell Basell as Profax 7823 SL5: a polyamide terpolymer PA6/66/6106T (40/36/24 wt%) with a melt point of l56°C, a specific gravity of 1.08 and a RV of 70-100 (ISO 307)

PA1 : a PA66 poly(hexamethylene adipamide) having a melt point of 262°C, a viscosity of 100 cm³/g and comprising 50 wt% glass fibers available from DuPont de Nemours, Inc., of Wilmington, DE (“DuPont”) as Zytel® polyamide 70G50HSLA BK039B PA2: PA610/6T (80:20 molar ratio) having a melt point of 2l4°C

PA3 : PA 612 having a melting point of 220°C and a density of 1.06 g/cc available from E.I. DuPont De Nemours and Company (DuPont) as Zytel® polyamide FE310001.

PA4: PA612/6T available from DuPont as Zytel® polyamide FE310088

PA5: PA610 having a melting point of 225 °C and a density of 1.08 g/cc available from

DuPont as Zytel® polyamide RS LC3090

PA6: PA1010 having a melting point of 203°C and a melt viscosity of 111 cm³/g, available from DuPont as Zytel® polyamide RS LC1010

PA7: PA6 having a melt point of 220°C, a density of 1.12 g/cc and a relative viscosity of 3.89-4.17 per ISO 307

PA8: PA66 having a melt point of l89°C, a density of 1.12 g/cm³ and a relative viscosity of 3.89-4.17 per ISO 307

PA9: poly(hexamethylene hexadecanedi amide) (PA616) having a melt point of 200°C PA10: a poly(hexamethylene dodecanediamide) (PA612) having a melt point of 280°C with an IV of 1.37

PA11 : Same as SL5 EVOH: an ethylene-vinyl alcohol co-polymer having 32 mol% vinyl alcohol with a melt point of l83°C and a density of 1.19 g/cc available from Kuraray America Co. as Eval™ F171B.

PP1 : a polypropylene homopolymer comprising 40% glass fibers and 60% polypropylene having a melt point of 205°C and a density of 1.33 g/cc, available from RTP Company, Winona, MN, USA as RTP 199 X 70836B.

Lap Shear

All lap shear measurements were made according to ASTM D3163-01 (2014), subsequently identified as ASTM D3163. All lap shear values are reported as MPa units. To determine the adhesive properties of overmolded polymer-metal hybrid articles, test samples were prepared according to lap shear test as follows: An aluminum coupon (5052-H32 available from Online Metals via onlinemetal s .com) having a thickness of 0.063 inches (1.6 mm) and 100 mm width and length, was thermally laminated to a 5 mil (0.005inch) thick bilayer film having an A1/A2 structure, in which surface layer Al is 2 mils thick and thermoplastic adhesive layer A2 is 3 mils thick, using a Glenro MPH laminator to provide a polymer metal hybrid test sample having an A1/A2/B structure. The polymer-metal hybrid test sample was then cut into a 4 inch x 2 inch (101.6mm x 50.8mm)(W by L) plate using a band saw. These plates were overmolded in a Nissie 180 Ton injection molding machine with PA1 into a 4-inch (101.6 mm) wide by 5-inch (127 mm)long by 0.125 inch (3.175 mm) thickness plaque. Thus, 3 inches (76.2 mm)of the overmolded plaque did not have metal underneath the overmolded polymer. Each plaque was then cut using a bandsaw into three test samples, each sample being 1 inch (25.4 mm) wide by 5 inches (127 mm) long. A 0.5 inch (12.7 mm) waste strip was discarded from the plaques’ outside edges along the 5 inch ( 127 mm) length. The resulting 1 inch (25.4 mm) wide x 5 inch (127 mm) long test samples have a 2 inch (50.8 mm) long metal overmolded test sample on one end with a 3 inch (76.2 mm) polymer tab on the opposite end (no metal underneath). The polyamide layer on the metal overmolded area of the test sample was cut by hand (in a jig) to provide a 1 inch (25.4 mm) wide by 0.25 inch (6.35 mm) long lap test area near the middle of the sample. The cut tensile bar test sample was tested using an Instron 5966 and a 2000 lb. (907.185 kgs) load cell at 0.05 inches/min (1.27 mm/min) according to ASTM D3163-01 (2014). For high temperature adhesion, the test samples were measured at 85 °C.

Initial adhesion (initial lap shear) values and high temperature adhesion (initial lap shear at 85 °C) values were obtained using these tensile bar test samples (overmolded polymer metal hybrid test samples) after molding and before the test samples were exposed to any subsequent environmental testing such as humidity exposure or elevated temperature cycling.

Lap Shear after Thermal Cycling (Thermal Stability)

Tensile bar test samples used for thermal stability testing were thermally cycled according to the following procedure:

Test samples were initially heated from room temperature (about 23 °C) to 85 °C at 2 °C /minute and held at 85 °C for 200 minutes. The sample was then cooled from 85°C to -35 °C over a period of 60 minutes (2 °C /minute) and held at -35 °C for 60 minutes. The sample was then heated from -35 °C to 23 °C at 2 °C /minute. This heating and cooling cycle was repeated for a total of 40 cycles to condition the test sample.

Lap shear of the thermally cycled tensile bar test samples was determined according to ASTM D3163-01 (2014) using the methods described above.

Lap Shear after Humidity Testing (Humidity Resistance)

Tensile bar test samples used for humidity resistance testing were exposed to 70 % relative humidity (RH) and 60 °C for 1000 hrs. in a Therm oForma environmental chamber. After RH exposure, the test samples were removed from the environmental chamber and allowed to cool to room temperature (about 23 °C). The cooled test samples were tested for lap shear according to ASTM D3163-01 (2014) using the methods described abov.

Flexural Modulus

Flexural modulus values for all samples were determined using a 3 -Point flexural test according to ISO 178:2010A. An Instron 4469 tensile tester having a support radius of 5 mm, a nose radius of 5 mm and a support span of 50.8 mm was used to determine flexural modulus. All samples were tested at a cross-head speed of 50.8 mm/min with the metal layer of the aluminum coupon facing upward. Test samples were prepared according to the following procedure.

Mechanically interlocked test samples were prepared as follows: An aluminum coupon (5052-H32 available from Online Metals) having a thickness of 1.6 mm and 150 mm width and length, was thermally laminated to a 5 mil (0.005 inch, 0.127 mm) thick bilayer film having an A1/A2 structure in which surface layer Al is 2 mils thick and thermoplastic adhesive layer A2 is 3 mils thick using a Glenro MPH laminator to provide polymer metal hybrid test samples having an A1/A2/B structure, where“B” refers to the aluminum coupon. The polymer-metal hybrid test samples were cut into 12.7 mm (0.5 inch) wide by 127 mm (5 inch) long test samples using a band saw. Four holes, each 4.76 mm (3/16 inch) in diameter, were drilled through the test samples along the lengthwise centerline of the sample at equal intervals of 25.4 mm (1 inch), on center. A 45-degree bevel was machined on the non-coated side (B side) of the drilled holes to increase their diameter at the metal surface to 6.0 mm (0.235 inch) to form mechanical fastening points when surface Al is over-molded with polymer. Comparative mechanically interlocked samples were made from aluminum coupons according to the method above, except that they were not laminated to the A1/A2 bilayer film.

Test samples which were not mechanically interlocked were prepared as follows:

Polymer-metal hybrid test samples were prepared and cut to size as described above with respect to mechanically interlocked samples, except that the non-interlocked samples had no holes for mechanical interlocking.

Both mechanically interlocked test samples and test samples which were not mechanically interlocked, as prepared above, were overmolded according to the following procedure:

Test samples were overmolded using a Nissie 180 Ton injection molding machine with PA1 or PP1 0.5 inch (12.7 mm) wide by 5 inch (127 mm) long by 0.25 inch (6.35 mm) thick flex bars with the overmolding polymer injected onto the side of the test sample comprising surface layer A (if present).

Initial Flexural Modulus

Initial flexural modulus of the test samples (before thermal cycling (zero thermal cycles) or humidity exposure) was determined according to ISO 178.

Spring Constant Bending Stiffness Because the polymer-metal hybrid test samples are multi-material flexural bars, the stiffness may be characterized by the spring constant“K” (Force versus deflection) which can be calculated from test sample (test bar) and flexural modulus data generated by ISO 178:2010 test method using the three-point bending formula K = (48 x FM x I)/L³, where FM is the flexural modulus of the test sample, I is the second moment of inertia (which is derived from (1/12 x width x height³ of the test sample), and L is the length of the test sample. Testing was performed with the metal side facing upward.

Table 1

The results in Table 1 show shear values achieved using various combinations of adhesives and surface layers when overmolded with reinforced polyamide or

polypropylene. Table 1 clearly shows that when an epoxy containing adhesive layer A2 (AL3) is used in combination with a polyamide surface layer (E5 and E6), the physical properties are superior to examples El to E4 which use a maleic anhydride grafted polymer as adhesive layer A2 (AL2), although examples El to E4 are acceptable for use in many applications. Cl and C4 do not use a surface layer and fail to exhibit the desired combination of physical properties. C2 and C3 show that polyethylene based adhesive layers do not perform as well as when polypropylene based adhesive layers are used. Although C5 exhibits desirable physical properties, the absence of a surface layer causes problems with mold deposits during overmolding.

Table 2

Table 2 shows the improvement in initial spring stiffness when an adhesive and surface layer are used in combination with mechanical interlocks. E7 to E9 show considerable improvement in initial spring stiffness compared to C6 which uses only mechanical interlocks. C7 and E10 use polypropylene as the overmolding polymer and show the same improvement in initial spring stiffness when a combination of mechanical interlocks and adhesive/surface layers are used (E10) compared to just mechanical interlocks (C7).

Table 3

Table 3 shows the use of different surface layer films (Al) in combination with an epoxy adhesive layer (AL3) which are overmolded with PA1 as the overmolding polymer. These results show that desirable lap shear values are obtained when different polyamides or EVOH are used as surface layer Al .

While certain of the preferred embodiments of the present invention have been described and specifically exemplified above, it is not intended that the invention be limited to such embodiments. Rather, it is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. An overmolded polymer-metal hybrid support beam comprising:

A) a surface layer comprising:

Al) at least one polyamide or polypropylene layer; and

A2) at least one adhesive layer;

B) a metal support beam having at least one opening before overmolding; and

C) a polymer composition overmolded onto surface layer A;

wherein:

adhesive layer A2 is in direct contact with polyamide or polypropylene layer Al and in direct contact with at least part of the external surface of metal support beam B;

polymer composition C is overmolded into at least one opening in metal support beam B; and

surface layer A is present on a portion of the surface of the metal support beam B, and said portion is overmolded with polymer composition C.

2. An overmolded polymer-metal hybrid support beam comprising:

A) a surface layer comprising:

Al) at least one polyamide or polypropylene layer;

A2) at least one adhesive layer;

B) a hollow metal support beam having an interior surface and an exterior surface;

Bl) at least one insert positioned inside the hollow metal support beam B; and

C) an overmolded polymer;

wherein:

adhesive layer A2 is in direct contact with polyamide or polypropylene layer Al and in direct contact with at least part of the exterior surface of the hollow metal support beam B;

at least a portion of surface layer A is overmolded with polymer C;

insert Bl comprises one or more ribs, said ribs being in direct contact with the interior surface of the hollow metal support beam B; at least a portion of surface layer A that is overmolded with polymer C is in contact with the exterior surface of the hollow metal support beam B at a location diametrically opposite the location of said ribs of insert Bl.

3. An overmolded polymer-metal hybrid support beam comprising:

A) a surface layer comprising:

Al) a polyamide or polypropylene layer; and

A2) at least one adhesive layer;

B) a metal support beam having an interior and exterior surface and having at least one opening before overmolding;

Bl) at least one insert positioned inside metal support beam B; and

C) an overmolded polymer;

wherein:

adhesive layer A2 is in direct contact with layer Al and in direct contact with at least part of the exterior surface of metal support beam B;

surface layer A is present on at least part of the metal support beam B which is overmolded with polymer C;

polymer composition C is overmolded into at least one opening in metal support beam B;

insert Bl comprises one or more ribs, one or more of said ribs being in direct contact with the interior surface of metal support beam B;

at least a portion of surface layer A that is overmolded with polymer C is in contact with the exterior surface of the metal support beam B at a location diametrically opposite the location of said ribs of insert Bl.

4. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein said support beam has a cross-section that is circular, oval, square, rectangular, or trapezoidal in shape.

5. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein adhesive layer A2 comprises:

i) from about 25 to 75 weight percent of at least one nonfunctionalized thermoplastic polyolefin having a melting point of from about 80 to 200 °C; and

ii) from about 75 to 25 weight percent of at least one functionalized thermoplastic polyolefin comprising from 0.02 to 10 weight percent total carboxyl functional group concentration when measured by ASTM

E168-16-A5;

wherein the sum of the weight percentages of (i) and (ii) is 100 wt%.

6. The overmolded polymer-metal hybrid support beam of claim 5 wherein at least one functionalized thermoplastic polyolefin comprises a total carboxyl functional group concentration of 0.02 to 2 weight percent.

7. The overmolded polymer-metal hybrid support beam of claim 5 wherein the at least one nonfunctionalized thermoplastic polyolefin is selected from the group consisting of ethylene/C3 to C8 a-olefm copolymers, ethylene/propylene/diene copolymers, polystyrene, polypropylene homopolymers, polypropylene copolymers, polyethylene homopolymers, low density polyethylene, and combinations of these; with the proviso that when polypropylene

homopolymers are present as a nonfunctionalized thermoplastic polyolefin, at least 20 weight percent of one additional nonfunctionalized thermoplastic polyolefin is present based on the total weight of nonfunctionalized

thermoplastic polyolefin.

8. The overmolded polymer-metal hybrid support beam of claim 5 wherein the at least one functionalized thermoplastic polyolefin is selected from the group consisting of maleic anhydride grafted homopolymer high density

polyethylenes, maleic anhydride grafted homopolymer polypropylenes, maleic anhydride grafted propyl ene/ethylene copolymers, and combinations of these.

9. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein metal support beam B or hollow metal support beam B comprises a metal selected from the group consisting of aluminum, stainless steel, carbon steel, brass, copper, and alloys of two or more of aluminum, stainless steel, carbon steel, brass, and copper.

10. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein said polyamide Al is selected from the group consisting of PA6, PA66, PA610/6T, PA612/6T, PA610, PA612, PA1010, PA6/66, PA 510/5T,

PA 512/5T, PA66/6T, PA6T/DT, PA6I/6T, PA6T/6I, PA6T/610,

PA6T/612, and combinations of these.

11. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein polymer composition C is a polyamide or polypropylene polymer.

12. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein the composition of the at least one polyamide or polypropylene layer Al is the same as polymer composition C.

13. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 wherein the at least one adhesive layer A2 comprises an epoxy component, and preferably wherein the at least one adhesive layer A2 does not comprise an epoxy curing agent.

14. The overmolded polymer-metal hybrid support beam of claim 12 wherein

polyamide or polyolefin layer Al comprises a polyamide and polymer composition C comprises a polyamide.

15. The overmolded polymer-metal hybrid support beam of any one of claims 1 to 3 in the form of an automotive cross-car beam, roof structure, front end modules, lift- gates, consumer electronic device, cell phone, or computer housing.