ES2386887T3 - Expandable epoxy resin based systems modified with thermoplastic polymers - Google Patents

Abstract

An expandable thermosetting composition, comprising: (a) at least one liquid epoxy resin; (b) at least one finely divided thermoplastic polymer powder having a corecortex structure; (c) at least one blowing agent; ( d) at least one curing agent; (e) at least one filler; and (f) fibers based on aramid fibers, carbon fibers, metal fibers, glass fibers, depoliamide fibers, polyethylene fibers, or polyester fibers.

Description

Expandable epoxy resin based systems modified with thermoplastic polymers

FIELD OF THE INVENTION

The present invention relates to an expandable thermosetting composition of a component, which produces foam and cures at a relatively low temperature (for example, approximately 135 ° C). The thermosetting composition of the present invention comprises a thermoplastic polymer powder having a core-crust structure that helps promote expansion of the composition when heated.

BACKGROUND OF THE INVENTION

It is a known fact that a large number of industries, for example the automobile industry, require parts that are both resistant and lightweight. An attempt to achieve this balance between strength and minimum weight uses hollow pieces constructed of relatively thin metal sheets. However, hollow metal parts easily deform. Consequently, as is also known, the presence of structural foam in the cavities of the hollow parts can improve the strength and stiffness of said pieces. For flat parts of the body of the car such as doors, roofs, the tailgate, or the bonnet cover, it is already known to increase the stiffness and hardness of said parts by means of joining sheets ("patches") ( patches ") based on expandable or non-expandable epoxy or polyurethane resins on said parts. Generally, said foams are either metallic foam materials or are prepared from formulations comprising a thermosetting resin such as an epoxy resin, a blowing agent and fillers and reinforcing agents, such as hollow glass microspheres, preferably these foams have a density of about 0.30-0.65 g / cm3 (about 20-40 lb / ft3) and are capable of withstanding heat in excess of 175 ° C, more preferably in excess of 200 ° C. Optional ingredients include, curing agents, process aids, stabilizers, dyes, and UV absorbers.

When the structural members of the car body are reinforced with expandable thermosetting resins, the resins are subjected to curing, often at the baking temperature of the car body in the paint coating process. However, these baking temperatures are relatively low and the car body structure may have cold spots that also inhibit the car body from reaching full baking temperature, preventing some thermosetting foams from fully expanding. Additionally, the temperature inside a paint drying oven tends rather to be uneven (for example, the temperature near the floor may be significantly lower than the temperature near the ceiling, implying that the thermosetting foam parts located relatively casualties in the vehicle body may only be exposed to a relatively low temperature). Therefore there is a need for thermostable compositions that have high degrees of expansion even at low temperatures.

EP-A-0 798 062 proposes structural components of metallic foam material, wherein the metallic foam material is produced from a metal powder and a blowing agent and is optionally formed between massive metal sheet components, in a press at high temperatures and high pressures. Said process is suitable only for large structural components that are produced separately outside the assembly line of a motor vehicle and are then introduced into the normal assembly chain. The incorporation of foaming materials of metallic foam is not possible under the conditions of the process of a normal vehicle assembly line.

US-A-4. 978. 562 describes a lintel of reinforcement of a door, specifically light in weight, of a composite material comprising a metal pipe that is partially filled with a specifically lightweight polymer with a cellular structure. It is proposed to mix thermosetting resins based on epoxy resins, vinyl ester resins, unsaturated polyester resins and polyurethane resins with the corresponding curing agents, fillers and cell forming agents in an extruder, cure this mixture forming a core and introduce it inside the metal pipe so that the core is fixed in the pipe by friction forces or mechanically. Alternatively, the polymer core can be produced by pouring a liquid or paste-like polymeric material, and compressed into the pipe. The reagent, thermoset and articles formed by thermal expansion are not described.

US-A-4,769,391 describes a preformed composite insert, to be inserted into a structured hollow body. This insert comprises a large number of thermoplastic granules of a mixture of a thermoplastic resin and expandable, unexpanded hollow microbeads, and an expanded polystyrene matrix that supports the aforementioned granules. The thermoplastic resin of the granules may here be a thermoplastic, such as a thermoplastic polyester, or it may be a thermosetting epoxy resin. After insertion of the component into the hollow body to be filled, the structural component is heated to a temperature that has the effect of "evaporation" of the expanded polystyrene - evaporation here means the decomposition of the expanded polystyrene into a thin or black carbon film -. At the same time, granulated thermoplastic grains expand and cure, when appropriate, the hollow spaces of large or small size remaining between the particles of individually expanded granules, depending on the degree of expansion of the granules.

Similarly, US-A-4,861,097 and US-A-4,901,500 specifically describe lintels of low-weight foamed polymer compound, and metal structures for reinforcing vehicle doors. According to this doctrine, the polymer core component is formed first by producing a liquid or paste-like material, which is then injected or poured into a channel-like structure, and then cured. Next, this component of the cured core is introduced into the structure of the hollow metal body. Alternatively, the core can be preformed or pre-cast by injection molding, and then inserted into the hollow space.

WO 89/08678 describes a process and compositions for reinforcing structural elements, the polymeric reinforcing material being a two component epoxy system, in which the first component is a paste-like composition based on epoxy resins, and the Second component is a mixture of filler, a colored pigment and a liquid curing agent with a paste-like consistency. The two components are mixed directly before the hollow structure is filled with the reinforcing material, introduced into the hollow body structure and cured, it being possible that the hollow body structure is optionally subjected to preheating.

Patent 96/37400 describes a W-shaped reinforcing structure, which comprises a thermally expandable resinous material, and is introduced before curing, into a hollow body to be reinforced. The polymeric reinforcing matrix preferably comprises a single component system, a paste-like system comprising an epoxy resin, an acrylonitrile / butadiene rubber, fillers, high strength glass beads, a curing agent, an accelerator and a blowing agent based on an azo compound or a hydrazide compound.

WO 98/15594 describes foamed products for use in the automobile industry, which are preferably based on liquid systems, two component epoxy systems, in which one component comprises a liquid epoxy resin and metal carbonates or bicarbonates, and The other component comprises pigments, optionally hollow pearls, and phosphoric acid. When the two components are mixed, these compositions cure with foaming. Jobs for reinforcement or stiffness of hollow structures is not described.

The polymeric materials of the references mentioned above, or are not suitable for the production of preformed molded parts that are thermally expanded by heating at a later time in time and are therefore thermostable, or if suitable for this, have as a rule Generally a very sticky surface that leads to contamination of stored areas, and on the other hand dust and dirt stick. In addition, the sticky surface of these molded parts prevents handling and in particular storage, for example, the stacking of several components on top of each other. For this reason, the reference molded parts are provided with a protective film that is removed immediately before use. However, these protective films make the production and use of these molded parts more expensive, and in addition the protective film must be removed after being removed, which causes additional costs.

To reduce the surface stickiness of said molded parts, WO 00/52086 proposes the production of thermally expandable thermosetting articles, from a mixture comprising at least one solid reactive resin, at least one reactive resin liquid, at least one reactive resin having a flexibilizing action and curing agents and / or accelerators or blowing agents. These shaped articles are suitable for stiffening and / or reinforcing thin-walled metal constructions and for giving rigidity to low-weight hollow metal constructions. Compared to the known thermosetting, thermally expandable shaped articles, the articles formed according to the doctrine of this specification are distinguished by greater dimensional stability in the uncured state and by the low surface tack. The processability and dimensional stability properties are achieved by mixing epoxy resins of different melting point. However, for example, a reduced surface tack can be achieved only with a temperature range of very narrow limits, so that a formulation that in effect is not sticky in winter, has a very sticky surface in summer. In addition, this procedure requires the use of large quantities of expensive resins and expensive curing systems. For an economical production of said expandable shaped articles by means of the injection molding process in particular, inconveniences in production and handling take place again and again, which is undesirable for the reliability of the production process.

US-A-4444818 describes, a thermosetting adhesive laminated body that is constructed from a layer of thermosetting resin in the form of a "prepreg" ("prepreg") and into which a reinforcing material is integrated. This specification also proposes a fixation on a prepreg face of a flattened tubular material that can recover its original tubular shape when the laminated reinforcing body is heated. The laminated prepreg body can comprise two different thermosetting resin layers. Epoxy resins are proposed as binders for the thermosetting layers of the prepreg. The tubular body or with a shape similar to pants is said here that it is made of polyethylene, ethylene / vinyl acetate copolymers, polypropylene, polystyrene or PVC or also of nitrile rubber. The manufacturing process of said laminated reinforcing bodies is expensive.

EP-A-230666 describes a process for the production of a thermosetting composition of a component, which forms by heating a system of interpenetrating network (IPN) of urethane-epoxy-silicone.

The specification in question proposes the manufacture from these compositions of laminated reinforcing metal bodies ("patches") that adhere directly to metal surfaces containing oils, such as oiled steel sheets. It is said that IPN is formed herein by a polyepoxide compound, a blocked polyamine curing agent and a prolonged chain polyurethane prepolymer, in which some isocyanate groups of the prepolymer are blocked with a hydroxyl functional polysiloxane.

EP-A-297036 discloses a laminated body comprising a support, for example a resin bonded fiberglass fabric, to which a thermosetting resin layer is applied. To protect the surface of sticky resin, a film-like cover of a material that contracts under the action of heat is provided. This film should be provided with grooves that widen to open after heat treatment, so that a part of the sticky surface is exposed. It is said that by this means it is no longer necessary to peel off the protective film before application of the laminated body. No information is given regarding the composition of the sticky resin layer.

EP-A-376880 discloses the arrangement of a laminated body for rigid flat bodies comprising a support layer of a curable synthetic resin material to which a reinforcement material bonded thereto or embedded therein is applied. In addition, an adhesive layer comprising a curable synthetic resin material provided optionally with fillers and other additives is applied and applied to the support layer facing the body to be stiff. To achieve the greatest possible reinforcement effect without deformation of the planar body (metal sheet), the adhesive layer should have a modulus of elasticity higher after curing of the synthetic resin, than the synthetic resin material curing of the support layer, and at the same time, the support layer and the adhesive layer in the cured state should have at least about the same coefficient of thermal expansion as the planar body to which stiffness must be given. The support layer here must comprise a fiberglass fabric and a mixture of liquid epoxy resins and solid epoxy resins and curing agents, and the adhesive layer should substantially comprise thermoset self-adhesive synthetic resins, and is constructed similarly whether it is from liquid epoxy resins as if it is from solid resins, as well as curing agents and fillers. EP-A-298024 similarly describes a method for stiffening metal sheets and plastic shaped articles with the aid of a flat body for stiffness, single layer or multi layer, in which at least one The layer comprises a synthetic resin that cures under the action of heat. This stiffening body should here be initially subjected to a first heat treatment, during which at least one surface of the rigid body becomes tacky as a result of this first heat treatment. The body for stiffness must then be applied with the sticky surface to the element to which stiffness must be given and the body for stiffness must then undergo a second heat treatment, until all the layers of the body to which stiffness must be given cured. It has been proposed that a layer of the reinforcing body be constructed from thermosetting epoxy resins and optionally comprises a fiberglass fabric. An epoxy-based, hot-melt adhesive, possibly based on polyurethane or copolyester is proposed as the second layer which should become tacky during the first heat treatment. Alternatively, this step should comprise a film that shrinks by heat so that a sticky layer is exposed after shrinkage.

WO 95/27000 patent describes a curable injection moldable composition for the reinforcement of hard and thin metal sheets, or plates. The composition is constructed from thermosetting resins, expandable hollow microbeads, and particulate reinforcement of ground glass fibers, ground carbon fibers and mixtures thereof. As thermosetting resin compositions different epoxy resins based on glycidyl ethers, glycidyl esters and glycidylamines are proposed.

Patent CA-A-2241073 describes a laminate for stiffening and reinforcing films, for rigid, thin-walled substrates. In accordance with the doctrine of this specification, the polymer should be cured with expansion in a lacquered furnace and thereby intimately bind with the internal surface of the base substrate to be reinforced. No information is given regarding the binder composition in this specification.

WO-A-01/46290 discloses compositions comprising a curing agent, an accelerator, a blowing agent, epoxy resins, a thermoplastic polymer powder and fillers.

Patents JP-A-07/088997 and JP-A-07/256808 describe compositions comprising an epoxy resin, a thermoplastic powder resin, an expanding agent, a curing agent and a plasticizer (filler).

US-A-2 965 586 describes a composition comprising an epoxy resin, a thermoplastic powder polymer (PVC), a curing amine, a blowing agent and a filler.

EP-A-0 500 009 describes a composition comprising an epoxy resin, a halogen-free thermoplastic powder resin, a latent curing agent, a foaming agent and a filler.

As can be deduced from the references described above, the sheet-shaped or frame-shaped laminated reinforcing bodies are substantially limited to epoxy resin based systems and polyurethane based systems. These, as a rule, communicate the required effect of stiffness, but do not meet the demand for a chemical base that is industrially hygienic and acceptable in terms of health. Reactive polyurethane systems as a general rule still contain monomeric diisocyanate residues. For this reason, workplaces where such compositions are used must be properly equipped with a gas ejection equipment, in order to be able to protect the people employed in these workplaces, from exposure to isocyanates. In the case of epoxy resin based systems, the dimensional stability of the components is determined by the composition of the epoxy resin mixture. The hardness adjustment of the laminated body in the uncured state is determined by the nature and relative content of the solid, semi-solid and liquid epoxy resin. The (desired) stickiness on the metal sheets with oil and the resistance to washing by various liquid procedures during the production of the vehicle body is also determined by these. High contents of low molecular weight liquid epoxy resins have so far been required for sticky laminated body compositions. As is already known, these liquid epoxy resins comprise low molecular weight epoxide compounds with a molecular weight of less than 700. The use of such epoxy compositions is undesirable for reasons of industrial hygiene, since these low molecular weight epoxide compounds can cause reactions. allergic or sensitive in contact with skin. Said uncured laminated bodies with a high content of liquid epoxides also have good adhesion to the substrates that must be stiff, but are not very resistant to process liquids such as washing and cleaning baths, baths phosphate and conversion, and electro-lacquered by immersion, and in particular washing liquids are applied under high pressure and at temperatures up to 75 ° C. Furthermore, said laminated bodies are very flexible and therefore are not very dimensionally stable and can only be stacked with an expensive specific packaging.

There is therefore a need for compositions based on an expandable resin, suitable for increasing the strength and stiffness of hollow parts, or the stiffness of flat parts.

SUMMARY OF THE INVENTION

An object of the present invention is to provide non-stick molded parts for reinforcement, and / or metal sheets for stiffness, or hollow metal bodies, which,

-

They are thermostable,

-

are thermally expandable

-

they are effective to stiffen and / or reinforce thin-walled metal structures

-

they can be cast in the injection molding process at low temperatures, preferably over

a support,

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They are dimensionally stable up to 50 ° C after injection molding,

-

they can be transported without an expensive container,

-

They are not expensive and are easy to manufacture, whether it is a composition or a piece

molded

Another object of the present invention comprises the provision of multilayer bodies, flat laminated bodies constructed from at least one thermosetting binder layer and at least one layer of reinforcing agents, the binder layer comprising at least one epoxy resin liquid reagent in a minor amount, optionally a flexibilizing agent, optionally a reactive diluent and at least one finely divided thermoplastic polymer powder, having a core-crust structure, a curing agent and / or an accelerator, an agent of blowing and fibers based on aramid fibers, carbon fibers, metal fibers, glass fibers, polyamide fibers, polyethylene fibers or polyester fibers. "Flat bodies" or "flat structure components" in the context of this application include not only completely flat structures but also include vehicle structures that include slightly curved or bent parts, such as doors, roofs, trunk doors, engine hoods, and the like.

In another version, the present invention provides an expandable thermosetting composition of a component for low temperature curing. The composition preferably expands to at least about 190% of its initial volume (ie, it has an expansion of at least about 90% compared to the initial volume) and cures at temperatures as low as about 135 ° C . The expandable thermosetting component composition contains an epoxy resin and employs a thermoplastic polymer powder having a core-capsule structure (more preferably an acrylic powder, particularly powder with a core-capsule structure) to facilitate or enhance the desired expansion while The composition is cured. The inventors have unexpectedly discovered that the addition of thermoplastic polymer powder having a core-shell structure provides new properties to the composition and to the thermosetting foam according to the present invention.

Additionally, the thermostable composition of the present invention does not require the production of a special intermediate product for incorporation into the thermostable composition. The thermosetting composition of the present invention also has a greater hardness compared to the prior art, which improves the handling ability of the composition. The tackiness of the thermosetting composition may vary depending on the requirements of the application. In addition, the greater hardness allows the production of the non-expanded thermosetting composition in the form of a powder, pellets, or other non-blocking form.

When the thermosetting composition of the present invention is used to reinforce or fill the structural members, such as those found in automobiles, the resulting foamed thermoset has both a high strength and a low weight when compared to the prior art. In such applications, the thermosetting composition of the present invention allows designers to reduce the weight of certain parts while maintaining rigidity and structural strength.

The expandable thermosetting composition of the present invention can be designed or formulated as "dimensionally stable", which means that a formed or molded part of the resin is free of stickiness and maintains the desired shape under normal handling conditions. The resin may thus be produced in the form of a free flowing powder or in the form of pellets, or it may be produced in the form of a block, a tape, a band, a cylinder, or otherwise.

Thermally expandable shaped articles are preferably manufactured by injection molding processes at low pressures and at low temperatures.

The present invention also provides a method for stiffening and / or reinforcing the structural components of the vehicle body, which method comprises the following essential process steps.

In a first step, the above-mentioned binder constituents are mixed homogeneously at temperatures below 110 ° C and the mixture is then transferred to an injection molding unit. This binder is injected into an injection mold at temperatures from 60 ° C to 110 ° C, preferably at temperatures from 70 ° C to 90 ° C, under controlled temperature conditions. This mold optionally contains a support of metallic or thermoplastic material on which the expandable binder is injected. The mold is then cooled to temperatures below 50 ° C and the surface of the expandable binder that is not sticky is released from the mold, so that the expandable formed articles can be packaged without special expense and even resist long transport without problems in summer to southern countries, without the use of refrigerated trucks being necessary.

For final use, the expandable molded part is inserted and fixed in the flat metal substrate or in the hollow space to which stiffness is desired, for example a vehicle body. During the subsequent heating process in the lacquer drying ovens, the vehicle body is brought to temperatures between 110 ° C and 200 ° C, and during this heating the volume of the formed article expands from 50 to 300% and The matrix of the reactive resin cures forming a thermostable.

The present invention thus also provides the use of expandable formed articles to stiffen and reinforce the components of flat metal sheets and / or hollow metal structures, in particular hollow components of the vehicle body, such as vehicle body racks, vehicle body supports, vehicle body columns and wider joints and gaps between the components of the vehicle body, in the manufacture of automobiles.

The present invention also provides a method for stiffening or for reinforcing the structural structural components of metal or plastic, which comprises the following essential procedural steps:

a) mixing of the binder constituents at temperatures below 110 ° C, b) extrusion of the binder at temperatures from 60 ° C to 110 ° C, preferably from 70 ° C to 90 ° C, optionally on a structure similar to a textile sheet or metal tape, c) optional application of a protective film to the binder layer

Laminated bodies produced in this way can optionally be temporarily stored or transported to the end user, as a rule, the car manufacturer. The optionally present protective film is removed from the binder layer, the laminated body is then applied to the structural component to be reinforced or stiffened, and the binder is cured at temperatures between 110 ° C and 210 ° C, preferably between 130 ° C and 180 ° C, in lacquer drying ovens, as a rule in the oven for curing the lacquer coating by electrodeposition.

DETAILED DESCRIPTION OF THE INVENTION

The expandable thermosetting composition of the present invention comprises:

a) at least one liquid epoxy resin;

b) at least one finely divided thermoplastic polymer powder, which has a core structure

bark, preferably an acrylic resin with a core-bark structure;

c) at least one blowing agent, either a chemical blowing agent or a physical agent of

blown;

d) optionally at least one activator / accelerator blowing agent;

e) at least one curing adduct, preferably including at least one amino-epoxy product;

f) at least one filler, preferably including hollow glass microspheres and / or hollow beads of

plastic;

g) optionally at least one rubber agent or other flexible agent;

h) optionally at least one reactive diluent,

i) optionally at least one coupling agent, and

j) fibers based on aramid fibers, carbon fibers, metal fibers, glass fibers, fiber fibers

polyamide, polyethylene fibers or polyester fibers.

Any of the thermostable resins having an average of more than one epoxy group (preferably two or more), per molecule known or referred to in the art, can be used as the epoxy resin component of the present invention. The epoxide equivalent of these polyepoxides can vary between 150 and 50,000, preferably between 170 and 5000. Epoxy resins are described for example in the chapter entitled "epoxy resins" in the second edition of the Encyclopedia of Polimer Science and Engineering (" Encyclopedia of Polymer Science and Engineering "), volume 6, pages 322-382 (1986). The polyepoxides may in principle be saturated, unsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic or heterocyclic polyepoxide compounds. Examples of suitable polyepoxides include polyglycidyl ethers, which are prepared by reacting epichlorohydrin or epibromhydrin or a polyphenol in the presence of alkali. The polyphenols that are suitable for this are, for example, resorcinol, pyrocatechol, hydroquinone, bisphenol A (bis- (4-hydroxy-phenyl) -2,2-propane), bisphenol F (bis (4-hydroxyphenyl) methane) , bis (4-hydroxyphenyl) -1,1-isobutane, 4,4'-dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane and 1,5-hydroxyphthalene. Other suitable polyphenols as the basis for polyglycidyl ethers are the known condensation products of phenol and formaldehyde or acetaldehyde of the Novolac resin type.

Other polyepoxides are polyglycidyl esters of polycarboxylic acids or hydroxycarboxylic acids, for example the reaction products of glycidol or epichlorohydrin with aliphatic or aromatic polycarboxylic acids such as oxalic acid, succinic acid, glutaric acid, phthalic acid, tetrahydrophthalic acid, terephthalic acid, dimer fatty acids or p-hydroxybenzoic acid, or beta-hydroxynaphthoic acid.

Other epoxides are those derived from the epoxidation products of olefinically unsaturated cycloaliphatic compounds, or from natural oils and fats or synthetic polyolefins. Other suitable polyepoxides include glycidylated amino alcohol compounds and aminophenol compounds, hydantoin diepoxides and urethane modified epoxy resins.

If desired, mixtures of epoxy resins may be employed; for example, mixtures of liquid epoxy resins (at room temperature), semi-solids, and / or solids can be used. Any of the epoxy resins available from commercial sources are suitable for use in the present invention. The epoxy resin or resins should be selected so as to provide the desired combination of properties both in the expandable thermosetting composition and in the final cured foam.

Particularly preferred are epoxy resins that are derived by reaction of bisphenol A or bisphenol F and epichlorohydrin. Liquid epoxy resins are preferably based on bisphenol A and have a sufficiently low molecular weight. Epoxy resins, which are liquid at room temperature generally have an equivalent epoxy weight of 150 to about 480 and a particularly preferred epoxy equivalent weight range of 182 to 350.

Expandable thermostable compositions are preferred, in which the liquid epoxy resins have a molecular weight greater than 350, preferably greater than 400.

Epoxy resins that have a flexibilizing action, such as, for example, adducts already known, butadiene / acrylonitrile copolymers with carboxyl terminals (CTBN) and liquid epoxy resins based on diglycidyl ether of bisphenol A, can be used as flexibilizing agents. . Specific examples are, for example, Hycar CTBN reaction products 1300 X8, 1300 X13 or 1300 X15 from B.F. Goodrich with liquid epoxy resins. The reaction products of the polyalkylene glycols with amino terminals (Jeff amines) with an excess of liquid polyepoxides can also be used. Such reaction products are described, for example, in WO 93/00381. The reaction products of the mercapto functional prepolymers or liquid thiocol polymers with an excess of polyepoxides, can in principle also be used according to the invention as flexible epoxy resins. However, the reaction products of polymeric fatty acids, in particular dimeric fatty acids, with epichlorohydrin, glycidol, or in particular, bisphenol A diglycidyl ether (DGBA) are very particularly preferred. The acrylonitrile copolymers with butadiene and / or isoprene and optionally the (meta) acrylic acid with an acrylonitrile content between 10 and 50% by weight, preferably between 20 and 40% by weight, and an acid content (meta) acrylic between 0.0 and 1% by weight, preferably between 0.0 and 0.1% by weight, are also suitable as flexibilizing agents. Mixtures of the flexibilizing agents mentioned above may also be used.

It may be preferred that the flexibilizing agent be selected from the group consisting of rubber modified epoxy resins, polyurethane modified epoxy resins, polyoxyalkylene adducts and polyepoxides with amino terminals, dimeric fatty acid adducts and bisphenol A diglycidyl ethers, polyether adducts in polyols on epoxy resins, epoxy resins modified with polysulfides or polyimercaptans, acrylonitrile copolymers with butadiene and / or isoprene and optionally acrylic (meta) acrylic acid with an acrylonitrile content between 10 and 50% by weight, preferably between 20 and 40 % by weight, and a content of (meta) acrylic acid between 0.0 and 1% by weight, preferably between 0.0 and 0.1% by weight, or mixtures of the flexibilizing agents mentioned above .

In addition to, or instead of, the reactive flexibilizing agents mentioned above, it may be particularly advantageous to include or more rubbers in the thermosetting composition, so that the additives harden the thermosetting foam and reduce the tendency of the thermosetting foam to crack under a stress As used herein, the term "rubber" includes both rubbers and elastomers. Suitable rubbers include thermoplastic rubbers as well as thermoset rubbers (reagents). Illustrative types of rubber include styrene-butadiene rubbers (SBR), nitrile-butadiene rubbers, butyl rubbers, polyisoprene, natural rubber, polybutadiene, chlorobutyl (neoprene) rubbers, isobutylene polymers, alpha elastomers -olefin, ethylene-propyl elastomers, chlorosulfonated polyethylenes, ethylene-propylene-dienes rubbers (EPDM), ethylene-vinyl acetate rubbers, halogenated rubbers, hydrogenated natural rubbers, and the like. Thermoplastic block copolymers are a particularly preferred class of rubbers for use in the present invention. These materials contain one or more base segments ("A") covalently bonded to one or more soft or elastomeric segments ("B"). Segments A can be polystyrene, poly (alpha-methylstyrene), polyethylene, polyurethane, polysulfone, polyester, polycarbonate or the like. Segments B may be polybutadiene, polyisoprene, poly (ethylene-cobutylene), polydimethylsiloxane, polyether, or the like. The block copolymers may have a linear, branched, radial, or starry structure, and may, for example, correspond to the general structure ABA, (AB) n, etc. The SIS, SEBS, and the SBS block copolymers are examples of specific types of such materials. Liquid rubbers such as butadiene-acrylonitrile copolymers, which can be functionalized with carboxyl groups, amine groups, or other groups capable of reacting with other components of thermosetting composition, can also be used.

Reactive diluents are another constituent of the binder composition according to a version of the invention. The reactive diluents in the context of this invention are low viscosity substances that contain epoxy groups (glycidyl ethers or glycidyl esters) and have an aliphatic or aromatic structure. These reactive diluents serve, on the one hand, to decrease the viscosity of the binder system above the softening point, and on the other hand, control the pregelification process in injection molding. Typical examples of reactive diluents that can be employed in accordance with the invention are mono-, di- or triglycidyl ethers of monoalcohols of 6 to 14 carbon atoms, or alkylphenols and monoglycidyl ethers of cashew nut oil, diglycidyl ethers of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4 butylene glycol, 1,5 pentanediol, 1,6 hexanodiol or cyclohexanedimethanol, triglycidyl ethers of trimethylolpropane, and glycidyl esters of 6 carboxylic acid atoms of carbon or mixtures thereof. Optionally, at least one diluent is a thermal transfer fluid; more preferably a thermal transfer fluid derived from an aromatic oil, a glycol oil, a petroleum oil, a fluorocarbon oil, and / or a silicone oil, and more preferably a thermal transfer fluid with oxidizing stability. Preferred thermal transfer fluids include MARLOTHERM LH, MARLOTHERM N, MARLOTHERM P1, MARLOTHERM P2, MARLOTHERM SH, and MARLOTHERM X from Sasol North America Inc.

The thermosetting composition of the present invention further comprises at least one thermoplastic polymer powder. The thermoplastic polymer powder may, in principle, be chosen from a large number of polymer powders, examples of which include but are not limited to homopolymers and copolymers of unsaturated carboxylic acids and esters of unsaturated carboxylic acids, such as for example alkyl esters of 1 to 6 carbon atoms of acrylic acid and methacrylic acid (in the art, generically called acrylic resins), vinyl acetate homopolymers, vinyl acetate copolymers, ethylene / vinyl acetate copolymers, homopolymers of vinyl chloride (PVC) or copolymers of vinyl chloride with vinyl acetate and / or (meta) vinyl acrylates, homo or copolymers of styrene or polyvinylbutyral. Particularly preferred thermoplastic polymers contain functional groups such as carboxyl groups, carboxylate groups, carboxylic acid groups and carboxylic anhydride or imidazole groups. Thermoplastic polymer powders should have an average particle size of less than 1 mm, preferably less than 350 µm, and with a very particular preference, less than 100 µm. Preferably, the thermoplastic polymer powder has a glass transition temperature from about 70 ° C to about 120 ° C, more preferably, from about 80 ° C to about 110 ° C.

Preferably, the thermoplastic polymer powder has a core-crust structure. For example, the core may comprise a type of thermoplastic containing reactive functional groups (for example, carboxyl groups, carboxylic acid anhydride groups, or imidazole groups), while the cortex may comprise a second type of thermoplastic which is non-reactive . It has been unexpectedly discovered that a thermoplastic polymer powder having a core-cortex morphology can help promote a greater degree of expansion when compared with the use of a comparable amount of a thermoplastic polymer powder having a composition corresponding to that of the core alone. This effect is particularly pronounced when a latent chemical blowing agent is used (ie a blowing agent that decomposes and releases a volatile gas when heated). Without pretending to be bound by a theory, it is believed that the increase in expansion is primarily due to the more efficient collection of gases generated after decomposition or volatilization of the blowing agent when heating the expandable resin formulation. Such core-crust thermoplastic polymer powders are well known in the art and are typically provided in the form of vaporized emulsions. See for example, patents EP 30999, EP 30590, DE 2722752 and US 5290857, each of which is incorporated herein by reference in its entirety. Core-bark thermoplastic polymer powders can be purchased from commercial sources such as certain materials sold under DEGALAN man by Roehm GmbH or Roehm America. Inc. DEGALAN 4899F, which has a glass transition temperature of approximately 95 ° C, is a particularly preferred polymethacrylate corecortex based thermoplastic polymer powder, suitable for use in the present invention.

It may be preferred that the thermoplastic polymer powder be a vinyl acetate homo or copolymer, an ethylene / vinyl acetate copolymer, a vinyl chloride homopolymer or copolymer, a styrene homo or copolymer, a (meta) homo or copolymer acrylate, or a polyvinylbutyral or a mixture of two or more of these polymers, and has an average particle size of less than 1 mm, preferably less than 350 µm, with very particular preference less than 100 µm.

In addition, it may be preferred that the thermoplastic polymer powder be present in an amount from 0.1% by weight to 40% by weight, preferably in an amount from 3% by weight to 15% by weight.

All known blowing agents, such as for example "chemical blowing agents" which release decomposition gases, or physical blowing agents ", ie hollow expansion beads, are in principle suitable as a blowing agent. Selection of the blowing agent system to be used is critical to achieve an expandable thermosetting composition, which is stable when stored for prolonged periods of time at a temperature of approximately room temperature (for example 15 to 40 ° C), but capable of causing foaming relatively quickly when heated to a moderately high temperature (for example 130 to 140 ° C) The use of chemical blowing agents that have decomposition temperatures within the range from about 120 to about 150 ° C It is especially preferred, particularly in combination with thermoplastic polymer particles having a structure no. eo-cortex Expandable thermosetting compositions containing chemical blowing agents typically provide thermosetting foams with better adhesion to oily metal surfaces, when compared to thermosetting foams produced using physical blowing agents, such as expandable microspheres. In a desired version of the invention, azodicarbonamide (sometimes also called 1,1'-azobisformamide, AZDC, or ADC), comprises at least part of the blowing agent system. Preferably, the blowing agent system is predominantly (i.e., greater than 50% by weight) azodicarbonamide. Even, preferably, at least 80% by weight of the total amount of the blowing agent system is azodicarbonamide. Blowing agents such as sulfonylhydrazides can be used as minor components of the blowing agent system. However, in one version, azodicarbonamide is essentially the blowing agent only present in the expandable thermosetting composition. Azodicarbonamide can be purchased from a varied number of commercial sources; for example, it is sold under the registered name of UNICELL by Dong Jin Chemical of South Korea and with the registered name of CELOGEN by Uniroyal Chemical. The particle size of the azodicarbonamide can be adjusted so that the desired foaming characteristics of the foamable composition are achieved. For example, it has been found that a relatively small particle size of azodicarbonamide tends to produce foams with a more uniform cell structure than a thicker azodicarbonamide quality. "Activated" or "modified" forms of azodicarbonamide can be advantageously employed in the present invention.

Expandable thermoplastic resin microspheres (which may contain, for example, volatile physical blowing agents such as hydrocarbons or halocarbons encapsulated in thermoplastic crusts) can also be used to produce the foamable resin. Thermoplastic crusts may consist of acrylic type resins such as polymethylmethacrylate, acrylic modified polystyrene, polyvinylidene chloride, styrene / MMA copolymers, and the like. Particularly preferred are the expandable microspheres that can be purchased from the Akzo Nobel AB firm under the registered name of EXPANCEL, or from the firm Pierce & Stevens with the registered name of DUALITE.

In some formulations, it may be desirable to also use an activator or accelerator of the blowing agent, to decrease the temperature at which the formation of gas from the blowing agent takes place or to increase the rate at which the gas is formed at a given cure temperature. Typically, from 0.1% to about 5% of the blowing agent accelerator / activator is used, based on the weight of the thermosetting composition, although the optimum amount will logically vary depending on the selected activator / accelerator, the amount of blowing agent, curing temperature and other variables. An excess of activator / accelerator must not be present in the thermostable composition, since storage stability may be undesirably compromised. Suitable activators / accelerators for the blowing agent include, but are not limited to, ureas (such as oil-treated urea to coat the surface, available from Uniroyal Chemical by the registered name of BIK OT), polyols, organic acids, amines, and lead, zinc, tin, calcium and cadmium oxide and salts (including salts of carboxylic acids).

Any of the latent curing agents (thermally activated) known in the art of epoxy resins can be employed in the present invention. Examples of such curing agents are guanidines, substituted guanidines, substituted ureas, melamine resins, guanamine derivatives, cyclic tertiary amines, aromatic amines and / or mixtures thereof. It is preferred for at least one curing agent, which is an epoxy amine adduct. Epoxy-amine adducts are well known in the art and are described for example from US Patent Nos. 3,756,984,4,066,625,4266,656,460,649,

Four.

 542. 202, 4. 546. 155, 5. 134. 239, 5. 407. 978, 5. 543, 486, 5. 548. 058, 5. 430. 112, 5. 464. 910, 5. 439.977,

5.

 717. 011, 5. 733. 954, 5.789. 498, 5.798. 399 and 5. 801. 218, each of which is incorporated herein by reference in its entirety. Said epoxy-amine adducts are the products of the reaction between one

or more amine compounds and one or more epoxy compounds. The carboxylic acid anhydrides, carboxylic acids, phenolic novolac resins, water, metal salts, and the like can also be used as additional reagents in the preparation of the epoxy-amine adduct or the adduct modified later once the amine and the epoxy resin have reacted. Preferably, the adduct is a solid that is insoluble in the epoxy resin component of the present invention at room temperature, but becomes soluble and functions as an accelerator to increase the cure rate when heated. While any type of amine can be employed (heterocyclic amines and / or amines containing at least one secondary nitrogen atom being preferred), imidazole compounds are particularly preferred. Illustrative are imidazoles that include 2-methyl imidazole, 2,4-dimethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, and the like. Other suitable amines include, but are not limited to, piperazines, piperidines, pyrazoles, purines, and triazoles. Any type of epoxy compounds can be used as the other starting material for the adduct, including the monofunctional, difunctional and polyfunctional epoxy compounds, such as those described above with respect to the epoxy resin component. Suitable epoxy-amine adducts can be purchased from commercial sources such as Ajinomoto, Inc., Shell, Pacific Anchor Chemical Company, and Asahi Chemical Industry Company Limited. Products sold by Ajinomoto with the registered name of AJICURE and by Air Products with the registered name of ANCAMINA are especially preferred for use in the present invention.

The curing of the epoxy resin (s) employed in the present invention can be further aided by the incorporation of other substances capable of promoting the desired hardening when heated. These materials are referred to herein as "curatives," but also include materials called by those skilled in the art as curing agents, hardeners, accelerators, activators, and catalysts. While certain curatives promote the curing of the epoxy resin by catalytic action, others participate directly in the reaction of the resin and are incorporated into the thermoset polymeric network that is formed. Although any of the curatives (curing agents) known in the field of epoxy resins (see the chapter in the Encyclopedia of Polymer Science and Engineering ("science and engineering of polymers") referenced above), can be used in the In addition to the epoxy-amine adduct, the invention employs one or more nitrogen-containing compounds, such as imidazoles, substituted ureas such as p-chlorophenylN, N-dimethylurea (MONURON), 3-phenyl-1 , 1-dimethylurea (FENURON) or 3,4-dichlorophenyl-N, N-dimethylurea (DIURON), amino compounds such as tertiary aryl amines or tertiary alkylamines, such as benzyldimethylamine, tris (dimethylamino ) Phenol, piperidine or piperidine derivatives, amine salts, and quaternary ammonium compounds as an auxiliary curative (s), is desirable (with the proviso that such compounds that cause an unacceptable high grade are avoided epo reaction xi resin under normal storage conditions). Dicyandiamide (sold commercially by Air Products under the registered name of "AMICURE CG") is a particularly preferred auxiliary cure, although other guarnidine compounds may also be employed. In a desirable version of the invention, dicyandiamide (preferably, about 0.5-8% by weight based on the total weight of the thermosetting composition) is used in combination with an epoxy-amine adduct (preferably about 0.1- 5% by weight) in the healing system. The healing system must, however, be selected so that it does not catalyze the cure of the thermosetting composition to any significant extent under typical storage conditions for an extended period. Preferably, the amounts and identities of the components of the healing system are selected such that the thermosetting composition remains stable for at least two weeks in storage at 54 ° C (130 ° F) without a significant loss of foam properties. Cured and does not expand in volume or decreases specific gravity to an unacceptable extent under such conditions, but produces foam and cures in approximately 10 minutes when heated to approximately 135 ° C.

As a general rule, binders according to the invention further comprise fillers that are already known by themselves, for example, various, ground or precipitated cretes, carbon black, calcium-magnesium carbonates, barite, and, in particular, silicate-based fillers, of the magnesium-calcium-aluminum silicate type, for example, wollastonite and chlorite.

It is especially desirable that one or more glass fillers be included in the thermosetting composition, since these fillers have been found to impart useful characteristics to the resulting foam (especially when used to reinforce a structural member). For example, hollow glass microspheres can be added to reduce the density of the foam, and therefore the total weight of the reinforced structural member, while maintaining good stiffness and tensile strength and high compressive strength. Commercially available hollow glass microspheres (sometimes also called microballoons or glass microbubbles) include materials sold by the Minnesota Mining and Manufacturing company under the SCOTCHLITE trademark, with appropriate grades including those sold under the designations B38, C15, K20 and VS 5500. Glass microspheres preferably have diameters in the range from about 5 to about 200 µm (more preferably, less than about 70 µm). The crush resistance of the hollow glass microspheres can be selected according to the desired characteristics of the cured thermosetting foam or the reinforced structural member containing said foam. However, microspheres with a crush resistance in excess of 500 psi are typically employed. In a particularly desirable version the hollow glass microspheres comprise from about 5 to about 50% by weight of the thermosetting composition. Fiberglass is another preferred type of glass filler, since it helps increase the strength and stiffness of the resulting foam. Fiberglass can be chopped, moved, or in other physical forms.

Other types of fillers may also be optionally present in the thermosetting composition. Any of the conventional inorganic or organic fillers known in the art of thermosetting resins may be employed, including, for example, silica (including smoked or pyrogenic silica, which can also act as a thixotropic or rheological control agent), calcium carbonate (including coated and / or precipitated calcium carbonate, which can also act as a thixotropic or rheological control agent, especially when it is in the form of fine particles), and fibers other than glass fibers (e.g. fibers of wollastonite, carbon fibers, ceramic fibers, aramid fibers), alumina, clays, sand, metals (for example aluminum powder, hollow steel beads), microspheres other than glass microspheres (including thermoplastic resin such as for example hollow beads based on phenolic resins, epoxy resins or polyesters, expanded hollow microbeads, with a wall material of copolymers of ester of (meta) acrylic acid, polystyrene, copolymers of styrene / (meta) acrylate, and in particular, of polyvinylidene chloride and copolymers of vinylidene chloride with acrylonitrile and / or esters of (meta) acrylic acid, microspheres ceramic and carbon, which can be solid or hollow, expanded or expandable), and any of the other organic or inorganic fillers, for example "fly ash" (Fillite), known in the field of epoxy resins. Organic fillings may also include those light weight fillings of natural origin such as ground nutshells, for example cashew nuts, coconut shells, or peanut shells, and cork flour or coke powder.

The thermally expandable, thermosetting shaped articles compositions further comprise fibers based on aramid fibers, carbon fibers, metal fibers - for example aluminum-, glass fibers, polyamide fibers, polyethylene fibers or polyester fibers, these fibers being preferably cellulose pulp fibers or cut fibers, which have a fiber length between 0.5 and 6 mm and a diameter of 5 to 20 µm. Polyamide fibers of the aramid fiber type or also polyester fibers are particularly preferred here.

To further increase the corrosion resistance of the composites containing the thermostable foams of this invention, the thermosetting composition may additionally contain one or more coupling agents (also known as wetting or adhesion promoters) and / or metal modified inorganic oxides . Suitable coupling agents include silanes and organometalates such as organic silanes, titanates, zirconates. Organic titanates and zirconates are already well known in the art and are described, for example in U.S. Pat. No. 6. 103. 784, which is incorporated herein in its entirety, by reference. Suitable inorganic metal modified oxides include alkaline earth metal modified silicates, for example, amorphous silica gels with exchanged calcium ions, such as SHIELDEX products, which can be purchased from the Grace Davison firm of W.R. Grace

The thermosetting compositions, according to the invention, may further comprise other usual auxiliary substances and additives, such as plasticizers, reactive diluents, rheological auxiliaries, wetting agents, adhesion promoters, anti-aging agents, stabilizers and / or pigments. The ratios of the quantities of the individual components may vary within relatively broad limits, according to the profile of requirements of the laminated body with respect to its process properties, flexibility, the action of the required stiffness and the adhesive bond with the substrates The typical margins of the essential components of the composition are:

(to)

thermoplastic polymer powder 0.1-40% by weight, preferably 3-15% by weight,

(b)

liquid epoxy resin 10-60% by weight, preferably 30-40% by weight,

(C)

reactive diluent 1-15% by weight, preferably 1-10% by weight,

(d)

flexibilizing agent 1-25% by weight, preferably 5-15% by weight,

(and)

curing agent and accelerator 1.5 to 5% by weight,

(F)

blowing agent 0.1 to 3% by weight

(g)

light weight filling 5-40% by weight

(h)

fillers 5-20% by weight

(i)

0-30% fibers by weight

(j)

pigments, stabilizers, agents

0-1% by weight coupling being the sum of the total constituents of 100% by weight.

It may be preferred that the expandable thermosetting composition comprises:

(to)

thermoplastic polymer powder 0.1-40% by weight, preferably 3-15% by weight,

(b)

liquid epoxy resin 10-60% by weight, preferably 30-40% by weight,

(C)

reactive diluent 1-15% by weight, preferably 1-10% by weight,

(d)

curing agent and accelerator 1.5 to 5% by weight,

(and)

blowing agent 0.1 to 3% by weight

(F)

light weight filling 5-40% by weight

(g)

fillers 5-20% by weight

(h)

0-30% fibers by weight

(i)

pigments 0-1% by weight being the sum of the total constituents of 100% by weight.

Furthermore, it may be preferred that in this version, at least one thermoplastic polymer powder has a core-crust structure, and the blowing agent is a chemical blowing agent selected from the group consisting of azobisisobutyronitrile, azodicarbonamide, di-nitroso -pentamethylenetetramine, 4,4'-oxybis (benzenesulfonic acid hydrazide), diphenyl-sulfone-3,3'-disulfohydrazide, benzene-1,3-disulfohydrazide and ptoluenesulfonyl semicarbazide.

To prepare the compositions according to the invention, the epoxy resin or resins, the flexibilizing agent, the reactive diluent and the thermoplastic polymer together with the fillers, fibers and pigments, are homogenized in a conventional mixing unit such as a planetary mixer , a kneader or the like, and the blowing agents and curing agents and accelerators are then mixed with the previous mixture, during which the temperature of the material should not exceed 110 ° C, although preferably, from 60 ° C to 90 ° C, especially during and after the addition of blowing agents and curing agents and / or accelerators. Compositions prepared in this way can be immediately stored or transported directly into the equipment for subsequent processing similar to an injection molding machine, an extruder or a calendering machine.

Depending on its consistency, flow properties, thixotropic properties, and other characteristics, the expandable thermosetting composition can be formed by extrusion, by injection molding, by hand, by stamping compression, by shape molding or by other means in any configuration desired. If the resin cannot be easily worked to receive a form at room temperature, it can be heated to facilitate the forming process (provided that care is taken not to heat the resin so high as to initiate premature foaming or curing, unless such heating takes place only in a short time before placing the resin in the position or location where the structural reinforcement is desired).

To produce the expandable molding, as a rule, a support is first inserted into the injection mold. This support can be made of metal, for example of a sheet of galvanized steel or aluminum, or also of a thermoplastic material, such as polyamide (PA), polyphenylene sulfide (PPS), polyphenylene ether (PPE), polyphenylene sulfone (PPSU) or polyphenyleneimide (PPI). These thermoplastic material supports can optionally also be reinforced with fiber, and should be distinguished by low water absorption and dimensional stability up to 180 ° C.

Once the mold has been closed, the expandable thermosetting composition, which has been heated to temperatures between 60 ° C and 110 ° C, preferably from 30 ° C to 90 ° C, is injected into the mold, then the molded part and removal of the molded part takes place. The binder is of low viscosity at the above-mentioned temperatures and can therefore be easily transferred by means of pumps and presses at low pressure. The molded parts obtained after being cooled are dimensionally stable and are not sticky until at least 50 ° C and do not require any specifically manufactured container to support the shape during storage. The shaped articles can therefore be transported to the end user even in summer on long transports in southern countries without using refrigerated trucks or refrigerated containers. In the end user, depending on the particular use, the molded parts are then introduced into the hollow space to be stiffened and reinforced, or the molded parts can optionally be fixed to the vehicle body components in the bare construction, such that the hollow space is formed in the first place in the subsequent joining processes when the vehicle body components are later joined. The molded parts according to the invention can also be applied to the flat metal sheet components, such as wide and / or hollow joints of the vehicle body components. As a general rule, the molded parts have dimensions so that empty spaces or joints and gaps are not completely filled in the unexpanded form, so that subsequent liquid processes such as washing baths and baths cleaning, phosphate baths and conversion baths and electro-deposited lacquers can completely wet the surface of the metal substrate. The so-called "bare construction furnaces" with temperatures up to 140 ° C are occasionally arranged in the production lines for pregelatinized adhesives and sealants, and in this case the molded parts according to the invention should not yet be expanded and cured in the oven. Naked construction Only in subsequent furnaces for curing electro-deposited lacquer, the expansion of the shaped article takes place from 50 to 100%, at temperatures between 110 ° C and 200 ° C, preferably between 140 ° C and 180 ° C, and at the same time, the matrix of the reactive resin of the binder system is cured to a thermostable, which then fills the empty spaces so that it can exert its action of communicating stiffness and reinforcement.

Another aspect of the present invention is a process for stiffening and / or reinforcing the structural components of the vehicle body, characterized by the following essential steps of the procedure:

a) mixing the binder constituents according to the present invention at temperatures by

below 110 ° C,

b) extrusion of the binder at temperatures from 60 ° C to 110 ° C, preferably from 70 ° C to 90 ° C,

optionally on a structure similar to a textile sheet, or a metal tape,

c) laminated body cooling,

d) application of the laminated body to the metal substrate, optionally heating the laminated body to

temperatures in the softening range,

e) heating the substrate at temperatures between 110 ° C and 200 ° C, preferably between 130 ° C and 180 ° C,

during which the reactive resin matrix cures to give a thermosetting resin on the substrate.

Another aspect of the present invention is a method for stiffening and / or reinforcing structural components of the vehicle body, characterized by the following essential steps of the procedure:

a) mixing the binder constituents according to the present invention at temperatures by

below 110 ° C, preferably below 50 ° C,

b) injection molding of the binder at temperatures from 60 ° C to 110 ° C, preferably from 70 ° C

up to 90 ° C, optionally on a support,

c) cooling of the molded part,

d) fixation of the laminated piece to the metal substrate, or introduction into the hollow space to which there is

to stiffen, optionally heating up to the softening temperature of the article

conformed,

e) heating at temperatures between 110 ° C and 200 ° C, preferably between 130 ° C and 180 ° C, during

which the volume of the article expands from 50 to 100% and the reactive resin matrix cures to give

a thermosetting resin.

The thermosetting compositions of the present invention can be used in any end use application, where an adhesive, a sealant or a coating is required. However, thermosetting compositions are especially used in the manufacture of automobiles and other vehicles to maintain or increase the strength of metal structural members such as rocker arms, pillars, radiator support joists, doors, reinforcing joists, and the like The use of structural reinforcement foams in such applications is described for example in U.S. Pat. US 4,901,500; 4,908,930; 4,751,249; 4,978,562; 4,995,545; 5,124,186; 5,575,526; 5,755,486; 4,923,902; 4,922,596; 4,861,097; 4,732,806; 4,695,343; 4,610,836; 6,068,424; 6,058,673; 6,003,274; 5,992,923; 5,888,600; 6,092,864; 6,079,180 and 5,884,960 (each of which is fully incorporated herein, by reference)

The thermosetting compositions of the present invention are also useful for the production of laminated bodies to give rigidity and reinforce flat structural components, in particular structural components of the body of a vehicle, such as for example the frames of the body of the vehicle, the doors, boot doors, engine hoods and / or roof components in car manufacturing.

The invention will be illustrated in more detail in the examples of the following versions, wherein the choice of examples is not intended to represent a limitation of the scope of the main subject of the invention, and is merely intended to represent individual versions and advantageous effects of the invention by means of a model.

5 Unless stated otherwise, all amounts of the constituents of the compositions given in the following examples are parts by weight or as many percent by weight.

EXAMPLES

10 Examples 1-5

Expandable thermostable compositions according to the invention were prepared, using the following components shown in Table B. The components are mixed together at a temperature of approximately 50 ° C

15 TABLE 1 Composition of the examples

Example 1 (% by weight)

Example 2 (% by weight) Example 3 (% by weight) Example 4 (% by weight) Example 5 (% by weight)

Epoxy resin1

53.35 58.35 61.51 57.85 60.22

Thermoplastic Polymer Powder2

7.00 7.00 3.63 3.50 3.61

Nitrile rubber3

- - - 5.00 ---

Heat transfer fluid4

5.00 - - - ---

Titanate coupling agent5

0.50 0.50 0.52 0.50 0.52

Blowing agent6

1.00 1.00 1.04 1.00 1.03

Glass microspheres7

21.60 21.60 22.38 21.60 22.29

Carbon black dye8

0.05 0.05 0.05 0.05 0.05

Curing agent epoxy-amine adduct9

0.60 0.60 0.62 0.60 2, 06

Curing agent dicyandiamide10

3.50 3.50 3.63 3.50 3.61

Blowing agent Accelerator11

0.20 0.20 0.21 0.20 0.21

Smoked Silica12

1.00 1.00 1.04 1.00 1.03

Aramid fiber13

0.50 0.50 0.52 0.50 0.52

Calcium Carbonate14

4.70 4.70 4.87 4.70 4.85

1. PEP 6134 HH from Peninsula Polymer. 2. DEGALAN 4899F from Röhm America, Inc. 3. NIPOL 1312 from Zeon. 4. MARLOTHERM of Sasol North America. 5. KR 55 by Kenrich Petrochemicals. 6. CELOGEN 780 of Uniroyal. 7. SCOTCHLITE VS5500 from 3M. 8. MONARCH 120 of Cabot Chemical. 9. AJICURE PN-40 from Ajinomoto. 10. AMICURE CG325 of Air Products. 11. BIK-OT of the Uniroyal. 12. CAB-O-SIL TS-720 of Cabot Chemical. 13. KEVLAR from Dupont. 14. ULTRA-PFLEX from Specialty Minerals.

TABLE 2 Measured properties of Examples 1 - 5

Example 1 (cured at 350 ° F)

Example 2 (cured at 350 ° F) Example 3 (cured at 350 ° F) Example 4 (cured at 350 ° F) Example 5 (cured at 275 ° F) Example 6 (cured at 350 ° F)

EXPANSION

Specific weight (uncured)

0.79 0.85 0.76 0.82 0.81 0.81

Specific weight (curing)

0.28 0.28 0.52 0.37 0.42 0.41

Expansion

180% 204% Four. Five% 125% 92% 99%

COMPRESSION

Strength (MPa)

20.6 15.7 41.9 27.7 31.8 28.1

Module (MPa)

1226 979 1829 1307 1414 1528

Shear force per turn (MPa)

2.95 ± 0.28 2.94 ± 0.11 2.49 ± 0.21 2.60 ± 0.19 1.70 ± 0.26 2.10 ± 0.16

5 To simulate injection molding, the compositions of the example described above were each pre-gelled for 5 minutes, which corresponds to the pre-gelling that takes place in the injection mold of an injection molding machine. After pre-gelling, the compositions of the example were dimensionally stable and had a non-sticky surface. To determine the degree of blowing (expansion), the density in the cured state, the compression force and the shear force of the cured article, the articles

10 were cured for 30 minutes at a temperature from about 135 to about 150 ° C. As shown in Table C above, a high degree of expansion and excellent compressive and tensile shear force were obtained, with the composition according to the present invention. In addition, the materials are very suitable for the reinforcement of hollow structural members.

15 Example 6

The components shown below were combined to provide an expandable thermosetting composition in accordance with the present invention.

20 Component% by weight Epoxy resin1 55.2 Blowing agent2 2.0 Wollastonite3 3.9 fiberglass cut 2.0

25 KEVLAR fibers 0.1 pyrolysis silica4 1.0 curing agent A5 3.0 curing agent B6 0.9 calcium carbonate7 5.2

30 glass microspheres 8 21.7 thermoplastic polymer powder 9 4.9

1 PEP 6134H, Peninsula Polymers 2 CELOGEN 780 azodicarbonamide, Uniroyal

35 Chemical Company 3 NYAD G, Nyco Minerals, Inc. 4 CAB-0-SIL TS720, Cabot Chemical 5 AMICURE CG-325 dicyandiamide

 Air Products & Chemicals

40 6 AJICURE PN-40 epoxy-amine adduct, Ajinomoto 7 ULTRA-PFLEX, Specialty Minerals 8 SCOTCHLITE VS 5500, 3M 9 DEGALAN 4899F core / bark emulsion powder

spray drying, Roehm America, Inc.

Three small portions (weighing approximately 5 g each) of the thermostable composition were aged for 2 hours at 80 ° C, then treated in an oven at 176 ° C for 30 minutes. The

The average density of the samples of the uncured thermosetting composition was 0.839 g / cc, while the average density of the samples of the cured thermosetting composition was 0.352 g / cc (139% expansion on average). When the amount of the blowing agent was increased to 3.5% by weight, an expansion of 120% on average was observed. By way of comparison, another thermostable composition was prepared as described above, except that DEGALAN 4858, (purchased from Roehm America, Inc.) was replaced by DEGALAN 4899F. DEGALAN 4858 is a spray-dried emulsion that has a composition similar to that of a DEGALAN 4899F core (ie DEGALAN 4858 does not have a core-crust structure). When this substitution was made, only 32% expansion was observed on average with a blowing agent level of 2.0% by weight. With a blowing agent level of 3.5% by weight, only 42% of

10 expansion on average. These tests demonstrate the advantages of employing thermoplastic polymer powder with a core-shell structure in the expandable thermostable compositions of the present invention. That is, the amount of expansion is much greater when a thermoplastic polymer powder of the core-crust type is used.

15 Examples 7-12

The constituents of the related compositions in the following table were mixed in a planetary mixer, with emptying device, until the mixture was homogeneous, during which it was ensured that the temperature of the material did not exceed 50 ° C.

20 Table 3

7 *

8 * 9 * 10 * eleven* 12 *

Liquid epoxy resin1)

55 55 55 55 - 55

Glycidyl ether2)

- - 5 - 10 ---

Solid epoxy resin3)

- - - - 55 ---

Core-bark acrylate4)

25 - - - - ---

Polyacrylate5)

- 25 - - - ---

Polyacrylate6)

- - 25 25 fifteen 0

Hollow microbeads7)

2 2 2 2 2 2

Diciandiamide

3 3 4 4 4 4

Amine Adduct8)

1.5 0.8 one one one one

Calcium carbonate9)

- 4.3 - 3 3 3

Fiberglass10)

- - - - - twenty

Hollow glass beads11)

13.5 10 9 10 - ---

Gel temperature in ºC

- 102 84 - - ---

Gel time (at 100 ° C), in seconds

- - 8 - - ---

Density, gelled g / cm3

- 0.987 0, 957 - - ---

Density, cured g / cm3

- 0, 509 0, 612 - - ---

Degree of blowing

- 94 57 - - ---

Compression force N / mm2

23.6 12.8 17.7 - - ---

Tensile shear force N / mm

- 3.9 3.2 - - -

* non-inventive examples Notes to table 3 1) DGBA-based liquid epoxy resin, 250 equivalent epoxide 2) monoglycidyl ether of an alcohol of 12 to 14 carbon atoms, equivalent epoxy 314 3) solid epoxy resin, approximate molecular weight 880, margin melting 50 to 62 ° C, equivalent epoxide 475 4) according to the doctrine of US 5290857 5) powdery polymethyl methacrylate, Tg 124 ° C 6) MMA copolymer / butyl methacrylate 7) blowing agent (hollow plastic beads "Expancel DU 140 ", Pierce & Stevens) 8) finely ground accelerator (amino adduct in epoxy resin, with epoxy and tertiary amino groups 9) precipitated 10) short fibers, 17 µm fiber diameter, 3 mm length 11) hollow glass beads ( Scotchlite VS 5500, compression force approximately 38 MPA, 3M)

To simulate injection molding, compositions 7-12 were in each case pre-gelled for 5 minutes at 110 ° C, which corresponds to pre-gelation in the injection mold of the injection molding machine. After this pregelification, the test samples were dimensionally stable and had a non-sticky surface. To determine the degree of blowing, the density in the cured state, the compression force of the shaped article and the shear force, the molded parts were kept in the oven for 38 minutes at 150 ° C. As can be seen from the test results in the table above, good degrees of blowing and excellent compression force and tensile shear force are achieved, with the parts

5 molded according to the invention. These materials are therefore excellently suitable for stiffening and reinforcing hollow structures in the automobile sector.

Examples 13-14

The constituents of the compositions of examples 13 and 14 listed below were mixed in a laboratory mixer, which could be emptied, until the mixture was homogeneous, during which time it was ensured that the temperature of the material did not exceed 50 ° C.

Table 4 15

13 *

14

Liquid epoxy resin1)

55% 46%

Glycidyl ether2)

7% 5.8%

Core / Crust Acrylate3)

10% 8.3%

Physical blowing agent4)

2% 1.7%

Diciandiamide

4% 3.3%

Amine Adduct5)

one% 0.8%

Calcium carbonate 6)

7% 5.8%

Fiberglass7)

- 16.7%

Hollow glass beads8)

14% 11.6%

* non-inventive examples 1) DGBA-based liquid epoxy resin, 250 equivalent epoxide 2) monoglycidyl ether of an alcohol of 12 to 14 carbon atoms, equivalent epoxy 314 3) copolymer based on methyl methacrylate / butyl methacrylate, Tg 95 ° C 4) plastic hollow pearls "Expancel DU 140", Pierce & Stevens 5) fine powder accelerator with epoxy and tertiary amino groups 6) precipitate 7) short fibers of 17 µm in diameter, 3 mm long 8) Scotchlite VS 5500, strength Compression 38 MPa, 3M

Laminated bodies were formed with a layer thickness of the laminated body of 1.2 and 4 mm, from the composition according to example 14 and their strength was measured, the pregelification conditions being from 5 minutes to 90 ° C.

20 For a 3-point bending test (according to DIN 53293 or EN 63), test samples with the dimensions of 120 mm x 25 mm x 2.8 mm (non-foamed) were prepared and applied to a metal sheet 0.8 mm thick ELO. After keeping the oven at 150 ° C for 38 minutes, the stiffness result obtained was measured, recording the measurement results in the following table 5. As can be deduced from the

25 results, the pregelification test samples have an outstanding resistance to handling. In addition, they have a very good stiffness result of the laminated bodies according to the invention, compared to the non-reinforced ELO sheet.

Table 5 30 Although the invention has been particularly shown and described with reference to the preferred versions thereof, it will be understood by those skilled in the art, that various changes in form and detail can be made, without departing from spirit and spirit. scope of the invention as defined in the appendix claims.

Resistance in N after

Stiffness result2)

1 mm

2 mm 3 mm

None1

40.7 83.8 88.4 2.8 times

Porcher 36971)

64.8 153.9 330.0 4,5 times

G + L EE 2011)

91.7 183.0 302.7 6.3 times

1 fiberglass fabric 2 compared to 0.8 mm ELO sheet

Claims (25)

1. An expandable thermosetting composition, comprising:

(to)

at least one liquid epoxy resin;

(b)

at least one finely divided thermoplastic polymer powder having a corecortex structure;

(C)

at least one blowing agent;

(d)

at least one curing agent;

(and)

at least one fill; Y

(F)

fibers based on aramid fibers, carbon fibers, metal fibers, glass fibers, polyamide fibers, polyethylene fibers, or polyester fibers.

2.

The expandable thermosetting composition of claim 1, further comprising a flexibilizing agent.

3.

The expandable thermosetting composition of claim 1 or 2, further comprising a reactive diluent.

Four.

The expandable thermosetting composition of any one of claims 1 to 3, characterized in that the liquid epoxy resin has a molecular weight greater than 350.

5.

The expandable thermosetting composition of claims 1 to 4, wherein at least one epoxy resin is a glycidyl ether of a polyhydric phenol.

6.

The expandable thermosetting composition of claims 2 to 5, characterized in that, the flexibilizing agent is selected from a rubber modified epoxy resin, a polyurethane modified epoxy resin, polyoxyalkylene adducts and polyepoxides with amino terminals, dimeric fatty acid adducts and bisphenol To diglycidyl ethers, polyether polyols adducts on epoxy resins, epoxy resins modified with polysulfide or polyamercaptan, acrylonitrile copolymers with butadiene and / or isoprene and optionally (meta) acrylic acid with an acrylonitrile content between 10 and 50% by weight, preferably between 20 and 40% by weight, and with a content of (meta) acrylic acid between 0.0 and 1% by weight, or mixtures of the aforementioned flexibilizing agents.

7.

The expandable thermosetting composition of claims 3 to 6, characterized in that, the reactive diluent is selected from mono-, di-, or triglycidyl ethers of mono alcohols of 6 to 14 carbon atoms, alkylphenols, nut-shell oil monoglycidyl ether cashews, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, trimethylolpropane, glycidyl ester of carboxylic acids from 6 to 24 carbon, or mixtures thereof.

8.

The expandable thermosetting composition of claims 1 to 7, characterized in that the thermoplastic polymer powder is a vinyl acetate homopolymer, an ethylene / vinyl acetate copolymer, a vinyl chloride homopolymer, a homo -o styrene copolymer, a homo- or copolymer of (meta) acrylate, or a polyvinyl butyrate or a mixture of two or more of these polymers and has an average particle size of less than 1 mm.

9.

The expandable thermosetting composition of claims 1 to 8, wherein the thermoplastic polymer powder is present in an amount from 0.1% by weight to 40% by weight.

10.

The expandable thermosetting composition of claims 1 to 9, which comprises at least one thermoplastic polymer powder having a core-shell structure and containing an acrylic resin.

eleven.

The expandable thermosetting composition of claims 1 to 10, wherein the thermoplastic polymer powder has a glass transition temperature of 70 ° C to 120 ° C.

12.

The expandable thermosetting composition of claims 1 to 11, which comprises a curing agent selected from the guanidines, substituted guanidines, substituted ureas, melamine resins, guanamine derivatives, cyclic tertiary amines, aromatic amines, amine adducts on epoxy resins or mixtures thereof.

13.

The expandable thermostable composition of claim 12, wherein the substituted guanidine is cyanoguanidine (dicyanodiamide) in an amount of up to 5% by weight.

14.

The expandable thermosetting composition of claim 12 or 13, which traditionally comprises an accelerator selected from 2-ethyl-2-methylimidazole, N-butylimidazole, benzimidazole and Nalkylimidazoles of 1 to 12 carbon atoms, or the N- arylimidazoles, triazine derivatives and imidazole / triazine compounds (for example Z-azines of 11 carbon atoms).

fifteen.

The expandable thermosetting composition of claims 1 to 14, which comprises at least one chemical blowing agent selected from the group consisting of azobisisobutyronitrile, azodicarbonamide, di-nitroso-pentamethylenetetramine, 4,4'-oxybis (benzenesulfonic acid hydrazide ), diphenyl-sulfone-3,3'-disulfohydrazide, benzene-1,3-disulfohydrazide and p-toluenesulfonyl semicarbazide.

16.

The expandable thermosetting composition of claims 1 to 14, which comprises at least one physical blowing agent consisting of expandable hollow microbeads based on polyvinylidene chloride copolymers or on acrylonitrile / (meta) acrylate copolymers.

17.

The expandable thermosetting composition of claims 1 to 16, characterized in that it additionally comprises fillers, being at least part of the fillers, light weight fillers selected from hollow metal beads, hollow glass beads, "Fillite" (flying ash) , hollow plastic beads based on phenolic resins, epoxy resins or polyesters or hollow microbeads with a wall material of (meta) acrylic acid copolymers, polystyrene, styrene / (meta) acrylate copolymers, and in particular chloride of polyvinylidene and copolymers of vinylidene chloride with acrylonitrile and / or esters of (meta) acrylic acid, hollow ceramic pearls or organic fillers of low weight, of natural origin, such as for example ground nuts, cork flour or powdered coke .

18.

A procedure for stiffness and / or to reinforce the structural components of the vehicle body, characterized by the following essential steps of the procedure:

a) mixing of the constituents of the binder according to at least one of the claims 1 to 17, at temperatures below 110 ° C, b) extrusion of the binder, at temperatures from 60 ° C to 110 ° C, c) laminated body cooling, d) application of the laminated body to the metal substrate, e) substrate heating at temperatures between 110 ° C and 200 ° C, during which the resin matrix Reactive cures to give a thermosetting resin on the substrate.

19.

An extruded laminated sheet prepared according to the steps of claim 18 (a) to (c), characterized in that, after step (c) at least one face is sticky at room temperature, and can be stacked without any change in the dimensions and shape at temperatures up to 50 ° C, the sticky face being provided with a protective film.

twenty.

The use of the laminated sheet in accordance with reinvidications 18 (a) to (c) or 19, to give rigidity and reinforce the structural components, in particular the structural components of the vehicle body, such as the body frames of the vehicle, the doors, the boot lid, the engine hood and / or the roof components in automobile manufacturing.

twenty-one.

A procedure to stiffen and / or reinforce the structural components of the vehicle body, characterized by the following essential process steps:

a) mixing of the constituents of the binder according to at least one of the claims 1 to 17, at temperatures below 110 ° C, b) injection molding of the binder, at temperatures from 60 ° C to 110 ° C, c) cooling of the molded part, d) fixation of the molded part to the metal substrate or introduction into the hollow space to which there is to give rigidity, e) heating at temperatures between 110 ° C and 200 ° C, during which the volume of the shaped article it expands from 50 to 100% and the matrix of the reactive resin cures to give a resin thermostable

22

The injection molded shaped article according to claim 21, characterized in that it is not sticky at room temperature after step (c).

2. 3.

The shaped injection molded article according to claims 21 (a) to (c) or 22, characterized in that the support is made of a sheet of galvanized steel, aluminum or thermoplastic materials, such as polyamide (PA), polyphenylene sulfide (PPS), polyphenylene ether (PPE), polyphenylene sulfone (PPSU) or polyphenylene imide (PPI).

24.

The shaped injection molded article according to claim 26, characterized in that the thermosetting composition is fiber reinforced.

25.

The use of the shaped articles according to one of the preceding claims 21 (a) to (c),

5 or 22 to 24 to stiffen and reinforce the components of a metal sheet and / or hollow metal structures, in particular the hollow components of the body of a vehicle, such as, for example, the frames of the body of a vehicle, the supports and the columns in automobile manufacturing.