GB2502317A

GB2502317A - Thermoactivable material with a curable resin support

Info

Publication number: GB2502317A
Application number: GB201209091A
Authority: GB
Inventors: Laurent Meistermann; Herwig De Roeck; Fabien Escudier; David Kosal; Jeffey Apfel
Original assignee: Zephyros Inc
Current assignee: Zephyros Inc
Priority date: 2012-05-24
Filing date: 2012-05-24
Publication date: 2013-11-27
Also published as: GB201209091D0

Abstract

A process comprises forming a thermoactivable material at a temperature below which it is activated; applying a curable resin to at least one surface of the material and curing the resin to provide a support for the material. Preferably, the thermoactivable material is a thermoexpandable foam material, or a heat activated structural adhesive. Curring of the resin is preferably by ultra-violet light. Preferably the thermoactivable material is shaped, or cut, prior to the application of the curable resin such that scrap material can be recovered and recycled. The laminar structure produced may be employed in cavities such as those in automobile structures; wherein the thermoactivable material is activated in a heat processing step such as the paint bake. A thermoactivable material provided with a curable resin, a structure comprising a thermoactivable material on a cured resin carrier and a structure comprising an activated material on a cured resin carrier are further disclosed.

Description

IMPROVEMENTS IN OR RELATING TO LAMINAR STRUCTURES

The present invention relates to improvements in or relating to laminar structures and their preparation and in particular to laminar structures comprising a thermoactivable material supported on a carrier. The therrnoactivable material can be an adhesive material and/or a foamable material that may be used in the transportation industries such as the automotive, the aerospace and the rail industry or other industries such as the furniture and construction industries. In a preferred embodiment the invention relates to laminar structures comprising a thermoexpandable (foamable) material that may be used to provide acoustic baffles and/or seals in automobiles or to provide reinforcement within automobiles. In particular the structures are such that they may be provided in the cavities of automobiles with the thermoactivatable material in an unactivated state and which is then activated, preferably foamed during subsequent automobile heat processing steps such as the paint bake or electrocoat bake ovens.

Particularly where large cavities are to be filled with foam it is necessary to provide support to the foarnable material as they do not have sufficient strength when heated to their foaming temperature, at which they tend to be molten, to retain their position within the cavity and they can sag and otherwise fail to provide a uniform foam structure. The support should have a heat deflection temperature (ASTM 0-648-07) above the temperatures to which the structure is subjected to cause toaming, typically from 130°C -210°C in an automobile assembly line.

The support is generally provided by carriers that are made of plastic or metal. Typical plastics include polyamides which may be filled such as with glass or aramid fibre, polyesters such as polybutylene terephthalate and polyethylene terephthalate. Typical metals include aluminium, steel or stainless steel.

Various processes are used for forming the carrier such as injection moulding, extrusion, and thernioforming. Several processes are used to couple the carrier to the thermoactivable material including overmoulding, co-extrusion, co-lamination, heat bonding, manual or automatic assembly with optional fasteners. Furthermore, careful temperature control and selection of ingredients is required to obtain the desired adhesion between the carrier and the thermoactivatable material without any undesirable preactivation of the thermoactivatable material.

The patent publication W000/03894 describes a process for making an automobile component using injection moulding for manufacturing a plastic carrier. The carrier is usually made of polyamide (PA6 or PA66), and the thermoactivable material may be assembled, overmoulded or heat bonded onto the carrier. The drawbacks of such processes are that the machine and tool (mold) are very expensive and the cycle time for making a component can be very long.

The patent publication W02005/002950.describes a laminar structure using an extruded band of thermoactivable material coupled with a metal or plastic carrier. The carrier is usually flexible and located upon the upper surface of the extrudate. The desired final shape is then obtained by cutting the laminate of the carrier and the extrudate and therefore a substantial quantity of scrap material is generated by the unused part of the extrudate. In order to recycle the scrap it is necessary to separate the thermoactivable material from the carrier which is time consuming and costly.

When structures of this type are used in automobiles the material for the carrier should be chosen to withstand the temperatures used in the automobile processing operations which can be temperatures of about 210°C for up to 40 minutes.

The present invention provides a simple product obtainable by a short cycle time manufacturing process which addresses these issues.

The present invention provides a thermo-activatable material provided with a curable resin, preferably curable by ultra violet light on at least one surface thereof the resin being curable to provide a carrier for the thermoactivatable material under conditions at which the thermoactivable material does not activate In a further embodiment the invention provides a structure comprising a thermoactivatable material supported on a carrier comprising a resin cured by ultra violet light.

In a further embodiment the invention provides a structure comprising an activated material supported on a carrier comprising a resin cured by ultra violet light.

In a further embodiment the invention provides a process comprising forming a thermoactivatable material at a temperature below at which it is activated, applying a resin curable by ultra violet light to at least one surface of the formed thermoactivatable material, curing the resin to provide a support for the thermoactivatable material.

It is also preferred that the resin is cured by exposure to ultra violet light. The thermoactivatable material may be activated by heat to flow and/or develop adhesive properties. Alternatively it may be activated by heat to foam. In a preferred embodiment it is activated to both foam and develop adhesive properties.

In a further embodiment of the process the thermoactivatable material is shaped prior to application of the curable resin. The shaping may be by stamping or die cutting a sheet of the thermoactivatable material. In this way any scrap material from the shaping operation may be recovered prior to contamination with the resin to facilitate recycling. Alternatively, the structure may be obtained by any suitable means such as co-extrusion or overmoulding.

The process may include the additional step of heating the structure to activate the thermoactivatable material although the activation step may be performed in a separate location from the process of the invention as set out above. For example, the structure with the thermoactivatable material in its activated state supported on the cured resin may be created in one location and transported to another location, such as an automobile assembly line where it is located in, for example, a vehicle cavity and the thermoactivatable material activated in subsequent automobile processing operations such as in the paint bake or e-coat bake ovens.

The Curable Resin The curable resin used in the present invention may be any suitable resin that can be cured.

In particular it is preferred to employ resins that can be cured by ultra violet light which is the preferred method of curing. The curable resin is preferably a resin that is liquid at ambient temperature so that it may be applied to the thermoactivatable material by dip coating, painting, spraying, roller coating, or doctor blade coating. The resin should be cured in any manner that does not deleteriously impact the thermoactivatable material, in particular the curing should not cause premature activation of the thermoactivatable material. The preferred resin will therefore depend upon the nature of the thermoactivatable material and the ingredients in its formulation. The resins employed are preferably cured by ultra violet radiation. The resin should have sufficient strength upon curing to provide the necessary support for the thermoactivatable material during and after the thermoactivation stage which is particularly important when the thermoactivtable material is foamable when heated as support is needed as the volume of liquid or semi liquid foaming material increases. After curing the resin preferably has a Ig greater than 150°C. It is preferred that the resin layer provided on the thermoactivatable material is of a thickness from 0.001 to 10mm preferably 0.1mm to 4mm so that when cured it provides sufficient support to the thermoactivatable material when it is heated to its activation temperature Examples of suitable preferred ultra violet curable resins are resins that are capable of crosslinking when combined with a photo initiator and exposed to ultra violet light. Upon exposure to ultra violet light, the photo initiator facilitates crosslinking by providing free radicals or a cationic species depending on the reactive resin choice. The resin may be any material capable of crosslinking when combined with suitable initiators and examples are materials containing reactive chemistries capable of crosslinking-such as acrylates supplied by Sartomer® and epoxies supplied by Dow Chemical. Acrylates and methacrylates including di-, tn-, tetra-and penta-functional monomers are particularly preferred. Acrylate oligomers including aliphatic urethane acrylates, aromatic urethane acrylates, epoxy acrylates, epoxy methacrylates, polyester acrylates and metallic acrylates. Materials available from Ciba Speciality Chemicals such as alpha-hydroxyketone, phenylglyoxylate, benzldimethyl-ketal, alpha-aminoketone, mono acyl phosphine, bis acyl phosphine, phosphine oxide, metallocene and lodonimum salt, lodonium, (4-methylpheny[4-(2-methylpropyl) phenyl]-, hexafluorophosphate(1 -) are particularly useful as photoinitiators.

The curable resin may contain fillers such as glass fibres, carbon fibre or aramid to provide additional strength or rigidity to the curable resin.

The resin may be applied over the entire surface of the thermoactivatable material although for certain applications it may be provided only over a part of the surface. It may be applied on one or both sides of the thermoactivatable material optionally in a predetermined pattern.

When the thermoactivatable material is foamable and the resin is applied to only one side of the thermoactivatable material, the expansion upon heating is directed mainly in the direction away from of the cured carrier resin. When the cured resin is applied to both sides of the material, the expansion is directed outward from the edges of the thermoexpandable material.

The Thermoactivatable Material The thermoactivatable material may be activated by heat to flow and/or develop adhesive properties, it may be activated to expand (foam) or activated to both foam and develop adhesive properties. The thermoactivatable material may be a structural adhesive such as those used for bonding components in automobile or aerospace assembly.

Where the thermoactivatable material is a thermoexpandable material it will be a heat activated material that will foam when heated. The material is preferably dry to the touch at ambient temperature and may be shaped in any form of desired pattern, placement or thickness, but is preferably of substantially uniform thickness. In certain instances the thermoexpandable material may also develop adhesive properties and cure (cross link) when heated to the expansion temperature.

A preferred heat expandable material is an expandable polymer or plastic. A particularly preferred material is a relatively high expansion polymeric material including one or more of polymers containing an acrylate and/or acetate groups. The expandable material may also be an elastomer or a combination thereof with other polymers. For example, and without limitation, the foam may be an ethylene vinyl acetate copolymer/rubber based material, including an ethylene copolymer or terpolymer.

A number of baffling or sealing foams are known in the art and they may be used as a thermo-expandable material in the present invention. A typical foam includes a polymeric base material, such as one or more ethylene-based polymers which, when compounded with appropriate ingredients (typically a blowing and curing agent) expands and cures in a reliable and predictable manner upon the application of heat. From a chemical standpoint for a thermally-activated material, the thermoexpandable material is usually initially processed as a flowable material before foaming and curing and upon foaming and curing, the material will typically cross-link making the material incapable of further flow.

The activatable material can be formed of other materials provided that the material selected is heat-activated and cures in a predictable and reliable manner under appropriate conditions for the selected application. One such material is the epoxy based resin disclosed in U.S. Patent No. 6,131,897. Some other possible materials include, but are not limited to, polyolefin materials, copolymers and terpolymers with at least one monomer type an alpha-olefin, phenol/formaldehyde materials, phenoxy materials and polyurethane materials with high glass transition temperatures. See also, U.S. Patent Nos. 5,766,719; 5,755,486; 5,575,526; and 5,932,680. In general, the desired characteristics of the material include high glass transition temperature (typically greater than 70°C), relatively high expansion and adhesion durability properties. In this manner, the material does not generally interfere with the materials systems employed by automobile manufacturers.

When a thermoexpandable material is used it is preferred that the thermo-expandable material expand by at least about 100%, 1000%, 2000% or 3000%.

An important consideration involved with the selection and formulation of the thermoactivatable material is the temperature at which activation will take place. Typically the material becomes reactive at higher processing temperatures, such as those encountered in an automobile assembly plant, when the component of the present invention is processed along with the automobile components at elevated temperatures or at higher applied energy levels, e.g., during paint curing steps. While temperatures encountered in an automobile assembly operation may be in the iange of about 148.89°C to 204.44°C (about 3QQO to 400°F), body and paint shop applications are commonly about 93.33°C (about 200° F) or slightly higher. If the material is thermoexpandable blowing agent activators can be incorporated into the composition to cause expansion at the required temperatures.

The thermoactivatable material preferably comprises 10% to 70% by weight of a polymeric admixture; about 6.0% to 20% tackifier; a curing agent; and optionally one or more fillers and when it is thermoexpandable a blowing agent, blowing agent accelerator or both..

The preferred polymeric material admixture includes a variety of different polymers, such as thermoplastics, elastomers, plastomers combination thereof or the like. For example, polymeis that could be used include polycarbonates, polymeis of olefins, styrenes, acrylates methacrylales, epoxies, silicones, phenolics, rubbers, polyphenylene oxides, terphthalates, acetates, methacrylates (e.g. ethylene methyl acrylate polymer) or mixtures thereof.

The polymeric admixture typically comprises a substantial portion of the activatable material (e.g. up to 85% by weight or greater). Preferably, the polymeiic admixture comprises about 25% to about 85%, more preferably about 40% to about 75% and even more preferably about 50% to about 70% by weight of the activatable material.

Although not requiied, it is preferable for the polymeiic admixture to include one oi moie polyacrylates. The acrylates may include polymers of simple acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, vinyl acrylate, copolymers or combinations thereof or the like The acrylates polymers may be copolymers with other chemical groups such as epoxy, ethylene, butylene, pentene or the like. When included the one or more acrylates typically comprise about 20% or less to about 95% or greater, more preferably about 40% to about 85% and even more preferably about 55% to about 75% by weight of the polymeric admixture.

It is also preferable although again, not required, that the polymeric admixture include polymers based on one or more acetates. The acetates may include, for example, acetate, methyl acetate, ethyl acetate, butyl acetate, vinyl acetate, copolymers or combinations theieof or the like. Moieovei these may be copolymers of acetates including other chemical groups such as epoxy, ethylene, butylene, pentene or the like. When included, the one or more acetates typically comprise about 5% or less to about 50% or greater, more preferably about 7% to about 35% and even more preferably about 15% to about 25% by weight of the polymeric admixture.

The thernioactivatable material may include an epoxy resin such as any of the conventional dimeric, oligomeric or polymeric epoxy materials containing at least one epoxy functional group. The polymer-based materials may be epoxy containing materials having one or more oxirane rings polymerizable by a ring opening reaction. In preferred embodiments, the activatable material includes up to about 20% of an epoxy resin. More preferably, the activatable material includes between about 0.1% and 10% by weight epoxy resin.

The epoxy may be aliphatic, cycloaliphatic, aromatic or the like. The epoxy may be supplied as a solid (e.g. as pellets, chunks, pieces or the like) or a liquid (e.g. an epoxy resin). The epoxy may include an ethylene copolymer or terpolymer that may possess an alpha-olefin.

As a copolymer or terpolymer the polymer is composed of two or three different monomers, i.e. small molecules with high chemical reactivity that are capable of linking up with similar molecules.

An epoxy resin may be added to the activatable material to increase properties such as adhesion! cohesion or the like of the material. Additionally, if the activatable material is thermoexpandable the epoxy resin may strengthen cell structure when the expandable material has foamed. One exemplary epoxy resin may be a phenolic resin, which may be a novalac type or other type resin. Other preferred epoxy containing materials may include a bisphenol-A epichlorochydrin ether polymer, or a bisphenol-A epoxy resin which may be modified with butadiene or another polymeric additive.

The thermoactivatable material may also include tackifiers or tackifying agents. Exemplary tackifiers include, without limitation, resins, phenolic resins (e.g. thermoplastic phenolic resins), aromatic resins, synthetic rubbers, alcohols or the like. According to one preferred embodiment, a hydrocarbon resin (e.g. a C5 resin, a C9 resin, a combination thereof or the like) is employed as a tackifier. The hydrocarbon resin may be saturated, unsaturated or partially unsaturated (i.e. have 1, 2, 3 or more degrees of unsaturation).

When used, the tackifier preferably comprises about 0.1% or less to about 30% or greater, more preferably about 2% to about 25% and even more preferably about 6% to about 20% by weight of the activatable material. The presence of the tackifier may assist in controlling cure rates which can, when the activatable material is thermoexpandable produce a more consistent or predictable expansion.

When the activatable material is thermoexpandable (foamable) one or more blowing agents are included in the thermo-expandable material for producing inert gasses upon heating that form, as desired, an open and/or closed cellular structure. The material expansion improves sealing capability, substrate wetting ability, adhesion to a substrate and acoustic damping.

The blowing agent may include one or more nitrogen containing groups such as amides, amines and the like. Examples of suitable blowing agents include azodicarbonamide, dinitrosopentamethylenetetramine,4,4-oxy-bis-(benzenesulphonylhydrazide), trihydrazinotriazine and N, N-dimethyl-N-N-dinitrosoterephthalamide.

An accelerator for the blowing agents may also be provided to increase the rate at which the blowing agents form inert gasses. One preferred blowing agent accelerator is a metal salt, e.g. a metal oxide, such as zinc oxide. Other preferred accelerators include modified and unmodified thiazoles or imidazoles, ureas or the like.

Amounts of blowing agents and blowing agent accelerators can vary widely depending upon the type of cellular structure desired, the desired amount of expansion of the thermo-expandable material, the desired rate of expansion and the like. Exemplary ranges for the amounts of blowing agents, blowing agent accelerators or both together in the expandable material range from about 0.1% by weight to about 25%, more preferably about 2% to about 20% and even more preferably about 7% to about 15% by weight of the thermoexpandable material.

One or more curing agents and/or curing agent accelerators may be included to the thermoactivtable material. Amounts of curing agents and curing agent accelerators can, like the blowing agents, vary widely within the activatable material depending upon the degree of cure that is desired. Where the activtable material is thermoexpandable (foaniable) the amount of curing agent can be selected according to the type of cellular structure desired which is governed by the desired amount of expansion of the thermoexpandable material, the desired rate of expansion and the desired structural properties of the expandable material. Exemplary range for effective amounts of the curing agents, curing agent accelerators or both range from about 1% by weight to about 7% by weight.

Useful curing agents are materials selected from aliphatic or aromatic amines or their respective adducts, amidoamines, polyamides, cycloaliphatic amines, e.g. anyhydrides, polycarboxylic polyesters, isocyanates, phenol-based resins (such as phenol or cresol novolak resins, copolymers such as those of phenol terpene, polyvinyl phenol, or bisphenol-A formaldehyde copolymers, bishydroxyphenyl alkanes or the like), peroxides or mixtures thereof. Particular preferred curing agents include modified and unmodified polyamines or polyamides such as triethylenetetramine, diethylenetriamine, tetraethylenepentamine, cyanoguanidine, dicyandiamines and the like. An accelerator for the curing agents (e.g. a modified or unmodified urea such as methylene diphenyl bis urea, an imidazole or a combination thereof) may also be provided for preparing the activatable material.

Though longer curing times are also possible, curing times of less than 5 minutes and even less than 30 seconds are possible.

The thermoactivatable material may also include one or more fillers, including but not limited to particulated materials (e.g. powder), beads, microspheres, nanoparticles or the like.

Preferably the filler includes a relatively low-density material that is generally non-reactive with the other components present in the activatable material. One of the fillers or other components of the material may be thixotropic for assisting in controlling flow of the material particularly when heated as well as properties such as tensile, compressive or shear strength.

Examples of fillers include mica, silica diatomaceous earth, glass, clay, talc, pigments, colorants! glass beads or bubbles, glass, carbon ceramic fibres, antioxidants, mineral or stone type fillers such as calcium carbonate, sodium carbonate. Such fillers, particularly clays, can assist the activatable material in levelling itself during flow of the material. The clays that may be used as fillers may include nanoparticles of clay and/or clays from the kaolinite, illite, chloritem, semcitite or sepiolite groups, which may be calcined. Examples of suitable fillers include, without limitation, talc, vermiculite, pyrophylite, sauconite, saponite, nontronite, montmorilonite or mixtures thereof. The clays may also include minor amounts of other ingredients such as carbonates, feldspars, micas and quartz. The fillers may also include ammonium chlorides such as dimethyl ammonium chloride and dimethyl benzyl ammonium chloride. Titanium dioxide might also be employed.

The amount of filler employed can range from 0% to 90% by weight, typically from about 3% to about 30% by weight, and more preferably about 10% to about 20% by weight.

Other additives, agents or performance modifiers may also be included in the thermoactivatable material as desired, including but not limited to a UV resistant agent, a flame retardant, an impact modifier, a heat stabilizer, a colorant, a processing aid, an anti-oxidant, a lubricant, a coagent, a reinforcement (e.g. chopped or continuous glass, glass fibre, ceramics and ceramic fibres, aramid fibres, aramid pulp, carbon fibre, acrylate fibre, polyamide fibre, polypropylene fibres, combinations thereof or the like).

When determining appropriate components for the thermoactivatable material the material should be formulated such that it will only activate at appropriate temperatures. The material should become activated to flow and if required, expand at higher processing temperatures.

As an example, temperatures such as those encountered in an automobile assembly plant may be appropriate, especially when the activatable material is processed along with the other components at elevated temperatures or at higher applied energy levels, e.g. during painting preparation steps. Temperatures encountered in many coating operations (e.g. in a paint curing oven), for instance, range up to about 180°C or higher, 200°C or higher, 250°C or higher are used to achieve a desired level of activation.

When the thermoactivatable material is a thermoexpandable material it is possible to make a family of materials wherein the members of the family have different expansion levels. Table A is illustrative of amounts of blowing agents and/or blowing agent accelerators which can be used for different degrees of expansion.

Weight Percent of Blowing Agent, Percent Volume of Expanded Material as Blowing Agent Accelerator or Both Compared to Non-Expanded Material Up to 1.5% 012.0% or greater Up to About 300% to about 400% or greater Up to 3.0% 013.5% or greater Up to About 700% to about 800% or greater Up to 5.0% or 5.5% or greater Up to About 1150% to about 1250% or greater Up to 7.0% or 8% or greater Up to About 1550% to about 1750% or greater Up to 9.0% or 10% or greater Up to About 2100% to about 2250% or greater Up to 13% or 14% or greater Up to About 2900% to about 3000% or greater Manufacturing Process The structures of the present invention are preferably produced in a continuous operation in which a strip of the thermoactivatable material is first produced, by, for example, extrusion at a temperature below that at which activation occurs. The strip may then be cut into pieces of the desired size before or after coating with the curable resin. It is preferred to cut before coating with the curable resin so that any scrap resulting from the cutting is not contaminated with the resin and can be recovered and recycled without any need for cleaning.

The strip or sections of the strip may then be coated with the curable resin which is preferably curable by exposure to ultra violet light such as by roller coating from a bath, spray coating, powder coating, passage through a liquid bath (perhaps for coating both sides of the strip of thermoexpandable material). The resin coating may then be cured by passage through a chamber such as a tunnel where it is exposed to curing conditions such as exposure to ultra violet light.

If there is a requirement for mounting the structure in place for example in an automobile frame, clips or pins may be provided within the resin prior to or after the curing of the resin.

The various processes that may be used are illustrated in the accompanying Figures in which Figure 1 is a flow chart of the process. It is believed it is self-explanatory.

Figure 2 shows roller coating of the curable resin onto the activatable material.

Figure 3 shows spray coating of the curable resin onto the activatable material.

Figure 4 shows powder coating of the curable resin onto the activatable material.

Figure 5 shows deposition of the curable resin from a liquid bath onto the activatable material.

Figure 6 shows deposition of the curable resin by direct jet drop stamping onto the activatable material.

Figure 7 shows an activatable material fully coated on one side with a curable resin.

Figure 8 shows an activatable material fully coated on both sides with a curable resin.

Figure 9 shows a component such as that shown in Figure 8 mounted in an automobile cavity.

Figure 10 shows how the component of Figure 9 would be after thermal expansion of the activatable material when the material is thermoexpandable.

In Figures 2 to 6 the same numerals indicate the same features and they show a pelletized thermoactivatable material (1) which may or may not be thermoexpandable being extruded from an extruder (2) onto a moving band. The extrudate of the thermoactivatable material is then cut into pieces of the desired shape and size (4) and then passes to the resin coating unit. Any scrap is removed from the material at (3) and this scrap can be recycled because, at that stage, it is not contaminated by the curable resin. The coating unit is a roller coater (5) in Figure 2, a spray coater (6) in Figure 3, a powder coater (7) in Figure 4, a liquid bath (8) in Figure 5 and an applicator associated with the cutting of the extrudate (9) in Figure 6.

In each instance the pieces of the thermoactivatable material coated with the curable resin then pass to a curing chamber (10) where the resin is cured by ultra violet light under conditions that do not cause activation of the thermoactivatable material. Typically the curing chamber is a tunnel where the curable resin is exposed to ultra violet radiation to produce the structure comprising the thermoactivatable material laminated to a layer of the cured resin.

Figure 7 shows a heat activated toamable layer (11) coated on one side with a layer of an ultra violet curable resin (12).

Figure 8 shows a heat activated foamable layer (11) coated on both sides with a layer of ultra violet curable resin (12).

Figure 9 shows a component similar to Figure 8 provided with two means of attachment (13) and (14) mounted within an automotive pillar (15) from which the cover has been removed for purposes of illustration.

Figure 10 shows the component of Figure 9 in which the thermoexpandable material has been expanded by heating to create the foam (16) to provide a foam structure within the pillar.

The invention therefore provides a simple process, employing simple equipment which allows the production of shaped parts of thermoactivatable material supported on a carrier comprising a cured resin which can be readily transported and subsequently activated within cavities such as, for example in automobile structures, in the embodiment where the thermoactivatable material is foamable the expansion can fill the cavity in the automobile structure. The invention also produces less scrap material and enables the scrap to be more readily reused. Although the invention has been described in relation to components for automobiles it is equally applicable to components in other transportation industries such as the aerospace and rail industries and other industries such as the construction and furniture industries.

Claims

CLAIMS1. A thermoactivatable material provided with a curable resin on at least one surface thereof the resin being curable to provide a carrier for the thermoactivatable material under conditions at which the thermoactivatable material does not activate.
2. A structure comprising a thermoactivatable material supported on a carrier comprising a cured resin.
3. A structure comprising an activated material supported on a carrier comprising a cured resin.
4. A structure according to any of the preceding claims wherein the resin is curable or cured by ultra violet light.
5. A structure according to any of the preceding claims in which the thermoactivatable material is a thermoexpandable material.
6. A structure according to any of the preceding claims in which the thermoactivated material is a heat activated structural adhesive.
7. A structure according to any of Claims 2 to 6 in which the cured resin has a Tg greater than 150°C.
8. A structure according to any of Claims 2 to 7 in which the cured resin has a heat deflection temperature (ASTM-D-648-07) above 130°C.
9. A structure according to any of Claims 1 to 8 in which the resin layer has a thickness of from 0.001 to 10mm.
10. A process comprising forming a thermoactivatable material at a temperature below that at which it is activated, applying a curable resin to at least one surface of the formed thermoactivatable material, curing the resin to provide a support for the thermoexpandable material.
11. A process according to Claim 10 in which the resin is cured by ultra violet light.
12. A process according to Claim 10 or Claim 11 in which the thermoactivatable material is shaped prior to application of the curable resin.
13. A process according to Claim 12 in which the scrap from the shaping is recovered and recycled.
14. A process according to any of Claims 10 to 13 comprising heating the structure to activate the thermoactivatable material.
15. A process according to Claim 14 in which the activation step is performed in a separate location from the process according to any of Claims 7 to 10.
16. A process according to any of Claims 10 to 15 in which the resin is liquid at ambient temperature.
17. A process according to any of Claims 10 to 16 in which after curing the resin has a Tg greater than 150°C.
18. A process according to any of Claims 10 to 17 in which the resin layer is provided on the thermactivatable material at a thickness from 0.001 to 10mm.
19. A process according to any of Claims 10 to 18 in which the resin is applied over the entire surface of the thermoactivatable material.
20. A process according to any of Claims 10 to 18 in which the resin is applied in any way or pattern that does not cover the entire surface of the thermoexpandable material.
21. A process according to any of Claim 10 to 20 in which the resin is applied to one side of the thermoactivatable material.
22. A process according to any of Claims 10 to 21 in which the thermoactivatable material is a thermoexpandable material that will foam when heated and is dry to the touch at ambient temperature.
23. A process according to any of Claims 10 to 22 in which the thermoactivatable material develops adhesive properties when activated by heat.
24. A piocess according to any of Claims 10 to 23 in which the thermoactivatable material is a thermoplastic or thermosefting resin.
25. A process according to any of Claims 10 to 24 in which the thermoactivatable material is activated at a temperature in the range 145°C to 210°C.
26. An automobile component according to any of Claims ito 9.
27. An automobile structure comprising a cavity containing a structure according to Claim 26.