Patent Description:
Interior automobile components commonly have cushioned, soft-touch aesthetic features. Molding compositions containing polymer foams play an important role in the manufacturing of such automobile components, due to the steadily increasing demand for automobiles with light-weight design. The "cushioned" feature can be imparted by compositions containing flexible polymer foam or elastomeric pad of varying thickness, with a "soft skin" material, which is a relatively harder material. Such automobile components can be produced in a core back injection molding process, producing multiple layers in the same process.

<CIT> discloses a molded body produced by foam-molding of a thermoplastic elastomer composition, which comprises a styrene-based elastomer and/or a hydrogenated product thereof, a softening agent for a hydrocarbon-based rubber and a modified polypropylene having a melt flow rate of <NUM> to <NUM>/<NUM> and a melt tension of <NUM> cN or more.

<CIT> describes a composite molded body being made by carrying out one piece molding of a foaming layer to a polyolefin-based composite resin layer, wherein the composition for of the foaming layer comprises a hydrogenated product of a block copolymer having an aromatic vinyl compound and a conjugated diene compound, a propylene-based polymer, a softening material for rubber and a propylene-based polymer mixture comprising a crystalline propylene polymer and an amorphous copolymer comprising propylene and ethylene.

<CIT> relates to a thermoplastic elastomer composition for foam injection molding, which includes a hydrogenated product of a block copolymer comprising a block composed of an aromatic vinyl compound-based monomer unit and a block composed of a conjugated diene compound-based monomer unit, the hydrogenated product having a weight-average molecular weight of not more than <NUM>,<NUM>, a propylene resin, a mineral oil and an ethylene-propylene copolymer rubber.

<CIT> discloses a foamable composition, which comprise one ore more selectively hydrogenated block copolymers having at least two resinous blocks of non-hydrogenated predominantly polymerized monovinyl arene and a selectively hydrogenated elastomeric block, one or more selectively hydrogenated block copolymers having at least two resinous blocks of non hydrogenated predominantly polymerized monovinyl arene and an selectively hydrogenated elastomeric block being derived prior to hydrogenation from a polymerized conjugated diene or dienes as a major component, a linear crystalline polymer comprising propylene as major component, a softener and a solid chemical nucleating agent.

There is a need for improved molding compositions for the production of articles such as interior automobile components via the core back injection molding process, having a high density reduction in combination with properties such as ease of processability and desirable hardness.

The present invention relates to a foamed article in accordance with claim <NUM>. The foamed article is made from a composition comprising: <NUM> phr of at least two different hydrogenated styrenic block copolymers (HSBC), a first HSBC and a second HSBC, having different molecular weights, a molecular weight ratio of at least <NUM>:<NUM>, respectively; and a weight ratio of ranging from <NUM>:<NUM> to <NUM>:<NUM>, respectively, wherein at least one of the two different HSBC is i) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of <NUM>%, a total molecular weight of <NUM>/mol and a melt flow rate of > <NUM>/<NUM> minutes at <NUM>° C and <NUM>, ii) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX, where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM>/<NUM> at <NUM>° C and <NUM>, or iii) a selectively hydrogenated copolymer with a formula S-EB/S-S or (S-EB/S)nX having a controlled distribution of styrene in the midblock where X is a coupling agent residue and n is <NUM>-<NUM> with a polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM>/<NUM> minutes at <NUM>° C and <NUM>, wherein the melt flow rate is measured according to ASTM D1238-<NUM>; <NUM>-<NUM> phr of a polypropylene having a melt flow of at least <NUM> g10/min according to ASTM D1238-<NUM> (<NUM>° C/<NUM>); and up to <NUM> phr of a plasticizer, selected from hydrocarbon based oils, fatty acids, triglyceride oils, and mixtures thereof. The composition has a melt flow rate of <NUM>-<NUM>/<NUM> (<NUM>, <NUM> per as measured by ASTM D1238-<NUM>), a Shore A hardness of <NUM>-<NUM> (<NUM> sec, <NUM>) as measured according to ISO <NUM>, a melt strength (F) of at least <NUM> N, and a melt strength (V) of at least <NUM>. The foamed article is formed by foam injection molding or foam extrusion and has a density reduced by at least <NUM>% relative to an article formed from the composition that has not been foamed. The foamed article has a non-foamed skin layer completely encasing a foamed inner core.

<FIG> is an optical microscopy image of a cross section of a foamed sample obtained from the formula of Example <NUM>.

The following terms are used in the specification and will have the following meanings:.

"phr" means parts per hundred parts of styrenic block copolymer (SBC).

"Molecular weight" refers to the styrene equivalent molecular weight in g/mol of a polymer block or a block copolymer. The molecular weights can be measured with gel permeation chromatography (GPC) using polystyrene calibration standards, such as is done according to ASTM <NUM>-<NUM>. The chromatograph is calibrated using commercially available polystyrene molecular weight standards. The molecular weight of polymers measured using GPC so calibrated are styrene equivalent molecular weights. The styrene equivalent molecular weight may be converted to true molecular weight when the styrene content of the polymer and the vinyl content of the diene segments are known. The detector can be a combination ultraviolet and refractive index detector. The molecular weights expressed herein are measured at the peak of the GPC trace, converted to true molecular weights, and are commonly referred to as "peak molecular weights", designated as Mp. Unless converted to true molecular weights, as described above, the molecular weights refer to the styrene equivalent peak molecular weights.

"Polystyrene content" or PSC of a block copolymer refers to the % weight of polymerized styrene in the block copolymer, calculated by dividing the sum of molecular weight of all polystyrene blocks by the total molecular weight of the block copolymer. PSC can be determined using any suitable methodology such as proton nuclear magnetic resonance (NMR).

"Melt Flow Rate" or "MFR" of components in the molding composition can be measured in accordance with ISO <NUM>-<NUM> at a temperature of <NUM> and under a load condition of <NUM>. Melt Flow Rate can also be measured according to ASTM D1238-<NUM> at a temperature of <NUM> and under a load condition of <NUM>.

"Shore A hardness" is a measure of indentation resistance of elastomeric or soft plastic materials based on the depth of penetration of a conical indentor, and can be measured according to ISO-<NUM>.

"Melt strength" refers to the resistance of the polymer melt to stretching, or extensional viscosity a polymer composition, which can be determined by the Goettfert Rheotens device, where a molten extrudate or fiber strand is pulled between two powered rollers as it leaves a downward-extruding orifice. As the speed of the rollers is increased, tension is created in the strand, which is measured by the Rheotens device. The force required to extend and then break the extrudate is defined as the melt strength, with the maximum draw-off speed or melt strength (V) as a relative measurement for the "elongation" of the melt, and the maximum force or melt strength (F) as a relative value for the melt strength measured in Newtons (N). The melt strength is measured at <NUM> unless otherwise indicated.

"A/B" refers to a polymer block having a controlled distribution of monoalkenyl arene units in the diene polymer block. For example, B/S refers to a polymer block having a controlled distribution of styrene in the butadiene block.

The disclosure relates to a "foamed" article having a foam inner layer, and a (more) dense soft skin. The article is formed from a molding composition comprising at least two styrenic block copolymer components, a high melt flow polypropylene, and optional plasticizers and additives.

Styrenic Block Copolymer (SBC) Components: The molding composition comprises two or more hydrogenated styrenic block copolymers (HSBCs) that are different in molecular weight. Under the proviso that at least one of the two different HSBC, is i) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of > <NUM>/<NUM> minutes at <NUM>° C and <NUM>, ii) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX, where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM>/<NUM> at <NUM>° C and <NUM>, or iii) a selectively hydrogenated copolymer with a formula S-EB/S-S or (S-EB/S)nX having a controlled distribution of styrene in the midblock where X is a coupling agent residue and n is <NUM>-<NUM> with a polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM>/<NUM> minutes at <NUM>° C and <NUM>, the different HSBCs suitable for use are selected from selectively hydrogenated styrene-diene block copolymers, selectively hydrogenated styrene-diene-styrene triblock copolymers, selectively hydrogenated styrene-diene diblock copolymers, selectively hydrogenated resins of styrene-diene-styrene triblock copolymers, selectively hydrogenated controlled distribution styrene-diene/styrene block copolymers, selectively hydrogenated controlled distribution styrene-diene/styrene-styrene block copolymers, and combinations thereof. The diene can be any conjugated diene, such as for example, butadiene, isoprene, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-butadiene, chloroprene, and piperylene, or any combination thereof.

In embodiments, the HSBC composition, prior to hydrogenation, comprises a styrenic diblock copolymer (SBC), comprising an A block and a B block designated A-B, a linear triblock copolymer of formula A-B-A where each A block can be of a different or identical peak molecular weight or of the same or different monoalkenyl arene content, and/or a multi-arm coupled block copolymer of formula (A-B)nX. In such aspects, A is a monoalkenyl arene block, B is a conjugated diene block, n is an integer from <NUM> to <NUM>, and X is the residue of a coupling agent. When the multi-arm coupled block copolymers of the formula (A-B)nX are utilized, n ranges from <NUM> to <NUM>.

In embodiments, the SBC is a controlled distribution styrenic block copolymer, which can be a styrenic diblock copolymer of formula A-B, a linear triblock copolymer of formula A-B-A, and/or a multi-arm coupled block copolymer of formula (A-B)nX where the type and values for A, B, X and n have been previously disclosed herein.

In one embodiment, the HSBC composition comprises a hydrogenated styrenic block copolymer (HSBC), which prior to hydrogenation, is one or more SBCs comprising:a styrenic diblock copolymer of formula A-B, a linear triblock copolymer of formula A-B-A, and/or a multi-arm coupled block copolymer of formula (A-B)nX where the type and values for A, B, X and n have been previously disclosed herein. In one embodiment, the HSBC is a hydrogenated resin of a styrene-isoprene-styrene triblock copolymer, a hydrogenated resin of a styrene-butadiene-styrene triblock copolymer, or a resin wherein a specific part of the polymerized conjugated diene (e.g., butadiene) is selectively hydrogenated. In one embodiment, the HSBC comprises a B block wherein addition of hydrogen molecules has occurred across greater than <NUM> mol%; or greater than <NUM> mol%; or greater than <NUM> mol% of the carbon-carbon double bonds within the B block. In another embodiment, the HSBC is a partially-saturated hydrogenated styrenic block copolymer with a B block wherein addition of hydrogen molecules has occurred across from <NUM> mol% to <NUM> mol%; or <NUM> mol% to <NUM> mol%; or <NUM> mol% to <NUM> mol% of the carbon-carbon double bonds within the B block.

The monoalkenyl arene block (A block) comprises any of styrene, o-methylstyrene, p-methyl styrene, p-tert-butyl styrene, <NUM>,<NUM>-dimethylstyrene, alpha-methylstyrene, vinylnaphthalene, vinyltoluene, vinylxylene, or mixtures thereof. In embodiments, the monoalkenyl arene block comprises a substantially pure monoalkenyl arene monomer. In some embodiment, styrene is the major component in the A block with minor proportions (less than <NUM> wt. %) of structurally related vinyl aromatic monomers such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, <NUM>,<NUM>-dimethylstyrene, α-methylstyrene, vinylnaphtalene, vinyltoluene, vinylxylene or combinations thereof. In some embodiments, the peak molecular weight of each monoalkenyl arene block (e.g., A block) is in the range of <NUM>,<NUM> - <NUM>,<NUM>/mol, or <NUM>,<NUM> - <NUM>,<NUM>/mol, or <NUM>,<NUM> - <NUM>,<NUM>/mol.

In embodiments, the monoalkenyl arene content of each A block is from <NUM> wt. % to <NUM> wt. %; or from <NUM> wt. to <NUM> wt. % based on the total weight of the SBC. In an aspect where the SBC is of formula A-B-A, the combined monoalkenyl arene content of all A blocks ranges from <NUM> wt. % to <NUM> wt. %; or from <NUM> wt. to <NUM> wt. % based on the total weight of the linear triblock copolymer. In some embodiments, the conjugated diene block (B block) comprises any suitable conjugated diene, e.g., conjugated diene having from <NUM> to <NUM> carbon atoms, conjugated diene formed from a butadiene monomer or an isoprene monomer that is a substantially pure monomer or contains minor proportions, up to <NUM>% by weight, of structurally related conjugated dienes, e.g., <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-butadiene, <NUM>,<NUM>-pentadiene and <NUM>,<NUM>-hexadiene.

In embodiments, the HSBC is a linear, selectively hydrogenated form of a block copolymer having a structure S-B-S or (S-B)<NUM>X, where B represents the conjugated diene block or the controlled distribution conjugated diene/styrene block, with peak molecular weight from <NUM>,<NUM> to <NUM>,<NUM>/mol; or <NUM>,<NUM> to <NUM>,<NUM>/mol; or <NUM>,<NUM> to <NUM>,<NUM>/mol, or less than <NUM>,<NUM>/mol.

In embodiments, the HSBC is a selectively hydrogenated copolymer having a structure, S-EB/S-S or (S-EB/S)nX, where X is a coupling agent residue and n is <NUM>-<NUM>. The selectively hydrogenated copolymer has a controlled distribution of styrene in the midblock, i.e., EB/S, a total polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of <<NUM>/<NUM> at <NUM>/<NUM>.

In embodiments, the HSBC is a selectively hydrogenated copolymer having a structure, S-EB/S-S or (S-EB/S)nX, where X is a coupling agent residue and n is <NUM>-<NUM>. The selectively hydrogenated copolymer has a controlled distribution of styrene in the midblock, with a total polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM> at <NUM>/<NUM>.

In embodiments, the HSBC is a selectively hydrogenated copolymer having a structure, S-EB-S or (S-EB)nX, where X is a coupling agent residue and n is <NUM>-<NUM>. The selectively hydrogenated copolymer has a total polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of about <NUM>/<NUM> at <NUM>/<NUM>, as disclosed in <CIT>.

In embodiments, the HSBC is a selectively hydrogenated copolymer having a formula, S-EB-S or (S-EB)nX, where X is a coupling agent residue and n is <NUM>-<NUM>. The selectively hydrogenated copolymer has a total polystyrene content of about <NUM>%, a total molecular weight of about <NUM>/mol, and a melt flow rate of ><NUM>/<NUM>, or <NUM>/<NUM> to <NUM>/<NUM>, at <NUM>/<NUM>.

In embodiments, the total polystyrene content (PSC) of the selectively hydrogenated block copolymer or selectively hydrogenated controlled distribution block copolymer is from <NUM> wt. % to <NUM> wt. %; or <NUM> wt. % to <NUM> wt. %; or <NUM> wt. % to <NUM> wt.

In embodiments when butadiene is the conjugated diene monomer, the vinyl content of the conjugated diene block (e.g., B block) ranges from <NUM> to <NUM> mol%, or <NUM> to <NUM> mol%, or <NUM> to <NUM> mol%. In aspects when isoprene is the conjugated diene monomer, the vinyl content of the B block ranges from <NUM> to <NUM> mol%, or <NUM> to <NUM> mol%, or <NUM> to <NUM> mol%.

In embodiments, the HSBC is a selectively hydrogenated styrene-diene block copolymer having a formula, S-EP-S, (S-EP)nX, S-EEP-S, (S-EEP)nX , S-EB-S, (S-EB)nX, S-EB/S-S, or (S-EB/S)nX, where S is a polystyrene block, EB is a hydrogenated polybutadiene block, EP is a hydrogenated polyisoprene block, EEP is a hydrogenated polymer block of butadiene and isoprene, n is <NUM> to <NUM>, and X is a coupling agent residue. The selectively hydrogenated styrene-diene block copolymer, prior to hydrogenation, are styrenic block copolymers having a polybutadiene block with a vinyl content of from <NUM> to <NUM> mol%. The selectively hydrogenated styrene-diene block copolymer, has a total PSC of <NUM> wt. % to <NUM> wt.

In embodiments, the selectively hydrogenated styrene-diene block copolymer, prior to hydrogenation, are styrenic block copolymers comprising a diblock copolymer of formula A-B or A-B/A, a linear triblock copolymer of formula A-B-A or A-B/A-A, or a multi-arm coupled block copolymer of formula (A-B)nX or (A-B/A)nX, where A is a monoalkenyl arene polymer block, B is a conjugated diene polymer block, and B/A indicates a polymer block having a controlled distribution of monoalkenyl arene in the conjugated diene polymer block, n is <NUM> to <NUM>, and X is a coupling agent residue. The selectively hydrogenated styrene-diene block copolymer, has at least <NUM> mol% of the polymerized butadiene units hydrogenated.

In embodiments, the selectively hydrogenated block copolymer or selectively hydrogenated controlled distribution block copolymer has a melt flow rate measured in accordance with ASTM D <NUM> at <NUM> and <NUM> mass of <NUM> to <NUM>/<NUM>; or alternatively <NUM> to <NUM>/<NUM>; or alternatively <NUM> to <NUM>/<NUM>.

The two different HSBC components are present in an amount of <NUM> phr, wherein the first and the second HSBC are present in a weight ratio ranging from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>, respectively. The at least two different HSBC components have a molecular weight ratio of at least <NUM>:<NUM>, or at least <NUM>:<NUM>, or at least <NUM>:<NUM>, or at least <NUM>:<NUM> or at least <NUM>:<NUM>.

Polypropylene Component: In embodiments, the polypropylene component is selected from: (i) a homopolymer of propylene, (ii) a random copolymer of propylene and an olefin selected from ethylene and C<NUM> -C<NUM> α-olefins, or (ii) a random terpolymer of propylene with two α-olefins selected from the group of ethylene and C<NUM> -C<NUM> α-olefins. The C<NUM> -C<NUM> α-olefins include linear and branched C<NUM> -C<NUM> α-olefins such as <NUM>-butene, <NUM>-pentene, <NUM>-methylpentene-<NUM>, <NUM>-methyl-<NUM>-butene, <NUM>-hexene, <NUM>-<NUM>-dimethyl-<NUM>-butene, <NUM>-heptene, <NUM>-methyl-<NUM>-hexene, <NUM>-octene and the like.

In embodiments, the propylene component is a homopolymer of propylene. In other embodiments, the propylene polymer is a heterophasic propylene copolymer ("HECO"). The copolymer comprises a polypropylene matrix with three different polypropylene fractions, having different melt flow rates, and wherein the HECO has a melt flow rate, MFR, (<NUM>), measured according to ISO <NUM>, of equal to or more than <NUM>/<NUM>.

The propylene polymer has a MFR higher than <NUM>/<NUM> as measured by ASTM D1238-<NUM> (<NUM>/<NUM>), or at least <NUM>/<NUM>, or at least <NUM>/<NUM>.

In embodiments, the polypropylene component is present in an amount of <NUM> to <NUM> phr, or less than <NUM> phr, or at least <NUM> phr, or <NUM> to <NUM> phr, based on <NUM> phr of the total amount of the HSBC components.

Plasticizer Component: The molding composition comprises a dispersion aid or a plasticizer, selected from aliphatic hydrocarbon based oils, fatty acids, triglyceride oils, and mixtures thereof. Examples include fatty oils (mixtures of animal or vegetable fatty acid triglycerides), mineral oils, and silicon oils.

In embodiments, the oil is selected from a mineral oil, a paraffinic oil, an oil-enriched in paraffin, and mixtures thereof. In some embodiments, the oil is a GTL-based process oil (or Fischer-Tropsch oil). In embodiments, the oil is a synthetic oil. In embodiments, the oil comprises diesel, biodiesel and carboxylic acid esters such as <NUM>-ethylhexyl oleate.

The plasticizer is present in amounts of <NUM> to <NUM> phr (based on <NUM> phr of the total HSBC components), or less than <NUM> phr, or at least <NUM> phr, or <NUM> to <NUM> phr.

Other Polymeric Ingredients: In embodiments, the molding composition optionally comprises other polymeric components selected from thermoplastic polyurethane, thermoplastic copolyester, and engineering thermoplastic resins (polyamide, polyester, polyphenylene ether), poly(aryl ether), poly(aryl sulfone), acetal resin, nitrile barrier resins, poly(methyl methacrylate), cyclic olefin copolymers, coumarone-indene resin, polyindene resin, poly(methyl indene) resin, polystyrene resin, vinyltoluene-alphamethylstyrene resin, alphamethylstyrene resin and polyphenylene ether, in particular poly(<NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether), copolymers thereof; and mixtures thereof.

Additives: In embodiments, the molding composition further comprises one or more additives selected from a nucleating agent, a clarifier, a release agent, an antioxidant, a stabilizer (such as a thermal stabilizer, a visible light stabilizer, an ultraviolet light stabilizer, a colorant, a flame retardant, a lubricant (such as calcium stearate), a synergist, a mold release agent, a flow enhancer, an anti-static agent, a glass filler, a filler that is different from the glass filler (such as talc), a scratch resistant additive / surface modifier (such as a silicone, a low density polyethylene that can be a long chain branched low density polyethylene), or a combination comprising at least one of the foregoing.

Examples of surface modifiers include ultra-high molecular weight polydialkyl siloxanes such as polydimethyl siloxanes, ultra high molecular weight polydialkyl siloxanes in combination with silica, polyolefin siloxanes and combinations thereof.

The additives may be present in the amount of <NUM> to <NUM> phr (based on <NUM> phr of total SBC components), or less than <NUM> phr, or at least <NUM> phr, or <NUM> to <NUM> phr.

Blowing Agent: In embodiments, blowing agents (i.e., propellants) are used with the foam injection molding (FIM) process. The blowing agents are not part of the molding composition, but added as an ingredient in the FIM process in an amount ranging from <NUM> to <NUM> wt. % based on the total weight of the molding composition.

The blowing agents can be any of chemical blowing agents, physical blowing agents, and/or microspheres. Examples of physical blowing agents include but are not limited to organic blowing agents, e.g., an aliphatic hydrocarbon such as nitrogen, carbon dioxide, water, propane, butane, pentane and cyclohexane; a halogenated hydrocarbon such as chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, and the like. Examples of chemical blowing agents include sodium hydrogencarbonate, ammonium hydrogencarbonate, ammonium chloride, ammonium carbonate and the like, which are blowing agents of thermal depcomposition type. Thermally explandable microsphere blowing agents typically have an outershell of a thermoplastic resin, and an expanding agent contained therein.

Properties of the Molding Composition: The molding composition is characterized as having a melt flow rate in the range of <NUM> to <NUM>/<NUM> (<NUM>, <NUM> per as measured by ASTM D1238-<NUM>), or at least <NUM>/<NUM>. , or from <NUM> to <NUM>/<NUM>, or at least <NUM>/<NUM>, or less than <NUM>/<NUM>.

In embodiments, the composition has a Shore A hardness from <NUM> to <NUM> (<NUM> sec, <NUM>) as measured according to ISO <NUM>, or in the range of <NUM> to <NUM>, or at least <NUM>.

In embodiments, the composition has a melt strength (F) or maximum force of at least <NUM> N, or at least <NUM> N, or at least <NUM> N, or at least <NUM>. In embodiments, the molding composition has a melt strength (V) or maximum draw-off speed of at least <NUM>, or at least <NUM>, or at least <NUM>, or at least <NUM>, or at least <NUM> when measured at <NUM>.

Methods for forming articles: The molding composition can be processed according to methods known in the art, by combining the individual components and blending to form a blend, extruding the blend to form pellets, which are subsequently used to form articles, such as injection molded soft skinned articles in a molding or extrusion process, e.g., foam injection molding (FIM) process or profile extrusion.

In embodiments, the foam injection molding method is by a so-called core-back type injection molding method, in which the molding composition is injected into a cavity space formed in a metal mold of an injection molding apparatus, and, immediately or after the lapse of a predetermined time, a movable mold or a movable core provided in the movable mold is retracted with a predetermined rate to a predetermined position to expand the cavity space, thereby achieving foaming. Since the metal mold usually has a temperature considerably lower than the temperature of the thermoplastic elastomer composition during injection, a dense skin layer with scarce foaming is formed at the surface of the injection foaming product, formed in contact with the surface of the cavity. In embodiments, the foaming product can also be integrally formed in contact with a surface of a base body made of a resin and the like. The laminated article can be formed by positioning the base body in advance in the cavity space, and injecting the composition to the surface of the base body.

The composition can be used in either a low pressure process or a high pressure process. In the low-pressure process with a relatively low cavity pressure, the mold cavity is filled with <NUM> to <NUM> % polymer gas melt. When the pressure drops in the mold, the melt can expand and fill up the remaining mold volume with a degree of foaming, in the range <NUM> to <NUM> %. In the high-pressure process (also known as "precision mold opening" or "breathing mold technology"), the mold cavity is completely filled with polymer melt and then immediately opened by a few millimeters. Through this opening of the cavity, a pressure drop occurs and the melt is able to foam. The opening takes place by the pull-back of the clamping unit.

In embodiments, the foamed article can be formed by foam extrusion. In foam extrusion, the composition is mixed with a suitable blowing agent to form a mixture. An extruder barrel is filled with a melt of the mixture, and the mixture is extruded through a profile die creating a foamed structured by reduction of pressure and/or temperature. The foamed article is then cut to the desired dimensions.

Applications: The molding composition can be used for producing a number of light-weight vehicle type applications, and in particular, door panels, instrument panels, and consoles, etc., with a integral foam structure having a foamed core and a compact non-foamed skin layer. In embodiments, the composition is used for making shoe sole components, packaging / padding materials. In embodiments, the composition is used for making seals, gaskets, and synthetic corks.

Foamed Articles: Foamed articles, made by injection molding the composition, are characterized as having an optimized density reduction, improved surface quality, uniform internal air holes, and minimal thickness of the non-foamed skin layer, e.g., a dense skin of <NUM> to <NUM>, or less than <NUM>, or less than <NUM> thick, with a coreback, or foamed inner core, of at least <NUM>, or at least <NUM>, or at least <NUM>, or at least <NUM>, or <NUM> to <NUM> thick.

Foamed articles, made by extrusion, the composition are characterized as having an optimized density reduction, improved surface qualify, and uniform internal air holes, and minimal thickness of the non-foamed skin layer, e.g., a dense skin of <NUM> to <NUM> or less than <NUM> thick with an foamed inner core of <NUM> to <NUM> thick or at least <NUM> thick.

In embodiments, the non-foamed skin layer completely encases the foamed inner core of the article.

In embodiments, the articles are characterized as having a density reduction of the molded article in the range of at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%. The density reduction is given by comparing the density after foaming and the density before foaming (i.e., density of the solid compact polymer).

The major components used in the examples follow:.

Examples <NUM>-<NUM>: The components, indicated in the tables as weight percent, were blended and extruded to form pellets, which are subsequently used to form foamed articles in a core-back injection molding process. Examples <NUM> to <NUM>, <NUM>, <NUM> and <NUM> are according to the present invention, whereas the others are not.

Properties of the molding composition were measured and are presented in Tables <NUM> and <NUM>. For the melt strength measurements, the Rheotens trials are performed with <NUM> wheel apparatus below an extruder, with the spin length of <NUM> and the extruder throughput of <NUM>/hr. The instrument is run by cooling with alcohol. From measured data, value curves are calculated and elongation viscosity model of Wagner is applied.

For the foamed articles, an injection foam molding machine with a <NUM> zone extruder was used, with a test plate of 90x90x2 mm. The mold temperature varied from <NUM> up to <NUM> (T mold of <NUM>, T zone <NUM> of <NUM>, T zone <NUM> of <NUM>, and T zone <NUM> of <NUM>. Injection speed was <NUM>%, injection time was <NUM> sec. Back pressure was <NUM> bar, with back pressure time of <NUM> seconds. Foaming agent including a physical foaming agent (<NUM>% CO2) and chemical foaming agent of <NUM>% hydrocerol CF40E. The produced foamedarticle exhibits a skin thickness of about <NUM>, with a dense-skin / foamed thickness ratio of <NUM> - <NUM>. The standard density reduction before and after the foaming was determined using a hydrostatic balance.

Results are as presented in Tables <NUM>-<NUM>. <FIG> is an optical microscopy image of the cross section of a foamed sample obtained from Example <NUM> formula.

Claim 1:
A foamed article made from a composition comprising:
<NUM> phr of at least two different hydrogenated styrenic block copolymers (HSBC), a first HSBC and a second HSBC, having different molecular weights, a molecular weight ratio of at least <NUM>:<NUM>, respectively; and a weight ratio of ranging from <NUM>:<NUM> to <NUM>:<NUM>, respectively, wherein at least one of the two different HSBC is i) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of <NUM>%, a total molecular weight of <NUM>/mol and a melt flow rate of > <NUM>/<NUM> minutes at <NUM>° C and <NUM>, ii) a selectively hydrogenated copolymer with a formula S-EB-S or (S-EB)nX, where X is a coupling agent residue and n is <NUM>-<NUM> having a polystyrene content of <NUM>%, a total molecular weight of <NUM>/mol, and a melt flow rate of <NUM>/<NUM> at <NUM>° C and <NUM>, or iii) a selectively hydrogenated copolymer with a formula S-EB/S-S or (S-EB/S)nX having a controlled distribution of styrene in the midblock where X is a coupling agent residue and n is <NUM>-<NUM> with a polystyrene content of <NUM>%, a total molecular weight of <NUM>/mol, and a melt flow rate of <NUM>/<NUM> minutes at <NUM>° C and <NUM>, wherein the total molecular weight is measured as disclosed in the description and the melt flow rate is measured according to ASTM D1238-<NUM>;
<NUM>-<NUM> phr of a polypropylene having a melt flow of at least <NUM>/<NUM> according to ASTM D1238-<NUM> (<NUM>° C./<NUM>); and
up to <NUM> phr of a plasticizer, selected from hydrocarbon based oils, fatty acids, triglyceride oils, and mixtures thereof;
wherein the composition has a melt flow rate of <NUM>-<NUM>/<NUM> (<NUM>, <NUM> per as measured by ASTM D1238-<NUM>), a Shore A hardness of <NUM>-<NUM> (<NUM> sec, <NUM>) as measured according to ISO <NUM>, a melt strength (F) of at least <NUM> N as determined in the Rheotens test described in the specification at <NUM>, and a melt strength (V) of at least <NUM> as determined in the Rheotens test described in the specification at <NUM>;
wherein the foamed article is formed by foam injection molding or foam extrusion;
wherein the foamed article has a density reduced by at least <NUM>% relative to an article formed from the composition that has not been foamed; and
wherein the foamed article has a non-foamed skin layer completely encasing a foamed inner core.