Recyclable vinylaromatic polymer composite article and process for producing the same

Abstract

The present invention relates to a vinylaromatic polymer composite article comprising at least two segments comprising vinylaromatic polymer compositions, each of which com- prises at least one vinylaromatic (co)polymer, wherein the percentages of repeating units derived from vinylaromatic monomers in each vinylaromatic (co)polymer differ from each other by less than 25 wt.-%. The vinylaromatic polymer composite article is character- ized by reduced delamination tendency and improved recyclability. The invention further relates to a process for producing the vinylaromatic polymer composite article and to the use of the obtained vinylaromatic polymer composite article as component of refrigerat- ing devices or freezing devices.

Description

[0001] Recyclable vinylaromatic polymer composite article and process for producing the same

[0002] Description

[0003] The present invention relates to a vinylaromatic polymer composite article comprising at least two segments comprising vinylaromatic polymer compositions, each of which comprises at least one vinylaromatic (co)polymer, wherein the percentages of repeating units derived from vinylaromatic monomers in each vinylaromatic (co)polymer differ from each other by less than 25 wt.-%. The vinylaromatic polymer composite article is characterized by reduced delamination tendency and improved recyclability. The invention further relates to a process for producing the vinylaromatic polymer composite article and to the use of the obtained vinylaromatic polymer composite article as component of refrigerating devices or freezing devices.

[0004] Refrigerating devices and freezing devices are widely used in the industry and private households. They typically comprise different materials including metals, glass, and different types of polymer compositions, in particular insulation material (often made of polyurethane foams) and liner (often made of vinylaromatic polymers). Due to the variety of different materials used in refrigerators and freezers, end-of-life recycling often requires complex processes.

[0005] The technology of recycling waste refrigerators and freezers mainly consists of two steps. The first step includes the manual disassembly to recover the accessories, such as drawers, shelfs, compressors, condensers, cooling equipment, wires and other easy-to-disassemble parts. Manual dismantling, mechanical separation and other methods are typically used to recycle the housings of waste refrigerators and freezers. Manual dismantling is a generally accepted solution in the industry. This is often followed by a second step: the remaining polymeric materials that have not been dismantled in the first step are subjected to thermal treatment for energy recovery, as it is currently difficult to mechanically recycle this mixture of different materials, which are often bonded or welded together. This is disadvantageous, because the materials are lost, and the material cycle is not closed. Moreover, improper incineration may produce carcinogenic substances, such as dioxin and furans.

[0006] Recycling and dismantling processes of waste refrigerators reported in the prior art are often not sufficiently sophisticated. For example, CN-A 101670355 describes a method for the treatment of waste refrigerators, with a manual disassembly step, followed by an extraction of the refrigerant liquids and a subsequent crushing process. Although the polyurethane foam is removed by wind-sifting, it is not further processed to a valuable recyclate. Other plastics are also not recycled. The majority of the polymers are wasted and not recycled.

[0007] CN-A 106269803 describes a dismantling and resource classification recycling procedure for waste refrigerators, in which iron, polyurethane foam, copper, aluminum, and ABS and other plastics can be recovered. However, the process of separation is often not complete and leads to contamination of the recovered polymers. EP-A 1747870 relates to a method and equipment for recycling plastic material, particularly plastic material combined with other materials, such as materials deriving from the recycling of household appliances, refrigerators, microwave ovens, air-conditioners, computers, telephones and other electronic devices. The recycling method comprises at least one isolating step and one surface purification step to obtain a polymer recyclate, in which said surface purification step is a simultaneous heat and abrasive treatment.

[0008] EP-A 1747823 relates to a cryo-treating method and equipment for recycling of various materials, particularly plastic materials combined with materials of a different nature, such as the one deriving from household appliances, e.g. refrigerators or the like.

[0009] US 2008 / 190819 relates to a method for separating differently additivated polymers based on polystyrene, copolymers and / or blends thereof. Said method is used in particular for recycling of flame-retardant plastic materials, as can be found in old electrical appliances. The method is characterized by a density separation with at least one liquid or gaseous separation medium.

[0010] EP-A 2399719 describes the removal of specific polystyrene parts as a first step in refrigerator recycling, to recover high quality polystyrene flakes.

[0011] All of the before mentioned technical solutions have in common that refrigerators, made of parts from different materials, need to be disassembled to ensure efficient recycling. However, it would be highly desirable to unify the used materials as much as technically possible and meaningful, in order to reduce the costly dismantling and separation steps. Especially the time and resource intensive removal of the (often polyurethane based) insulation foam, sticking to the backside of the refrigerator liner, is an important cost position, which should be minimized.

[0012] Removal and recycling of polyurethane insulation foams as described in CN-A 113698665 and in CN-A 115026110 is possible by chemical recycling methods such as alcoholysis, but this requires additional processing steps and increases complexity and costs in the recycling process.

[0013] One challenge in mechanical recycling of polymer materials obtained from household appliances and other electric and electronic devices is the negative impact on the mechanical properties of the recycled polymer materials when the different polymer classes are not separated properly before re-extrusion. For example, the extrusion of a mixture of acrylonitrile-butadiene- styrene copolymer (ABS) and polystyrene (PS) waste typically results in a blend with large domains and poor mechanical properties such as flexural modulus, elongation at break and impact strength. This is caused by the incompatibility of the different polymer classes, e.g. ABS and PS in this example. This can be overcome at least partially by the use of compatibilizers. However, with respect to simplicity and cost-effectiveness, it would be advantageous if only miscible polymers are used in a single device. Then the polymer parts of the device can be directly shredded and mechanically recycled without the addition of a compatibilizer, and recyclable polymer materials (recyclates) with good quality are obtained.

[0014] Expandable polystyrene compositions are known in the art. For example, CN-A 113444280 describes the use of a polystyrene bead foam in refrigeration housings. JP 2020-063904 and JP 2017-133784 describe the use of styrene foam for insulation of a refrigerator, providing a low delamination between liner and foam and a good miscibility in the recycling process. However, no details are disclosed how a high insulation behavior could be maintained over the lifetime of the appliance.

[0015] WO 2009 / 120624 describes a method of preparing a refrigeration insulation liner in the shape of a multilayer polymeric sheet with at least one foam layer and at least one solid layer adjacent to the foam layer. A method of preparing a refrigerator liner by co-extruding a foamed polystyrene layer between two solid layers of high impact polystyrene to form a sheet, thermoforming the sheet into the liner, and incorporating the liner into the refrigeration device is described. However, the insulation performance of the foam layer is not sufficient for today's refrigerators and does not make the additional use of polyurethane based insulation obsolete.

[0016] JP 2004-075926 discloses expandable acrylonitrile-styrene resin particles. The resin particles are impregnated with foaming agent and the surface is coated with a fluorine-containing vinyl type copolymer. The foamed shaped article obtained by foam molding is recommended for refrigerators because it excels in preventing the permeation of water that is contaminated with undesired ingredients such as surfactants and oils. However, the use of fluorinated copolymers is not desirable from an environmental and recycling point of view.

[0017] In view of increasingly demanding requirements regarding the energy efficiency of refrigerating and freezing equipment as well as increasing demands concerning the recyclability of waste materials, there is a steadily increasing need in polymer composite materials, which show a superior insulation behavior, a low delamination tendency of foam and liner, a high resistance against the used blowing agent, and a good recyclability to recyclates with acceptable properties, without the need of disassembling, at the same time.

[0018] A solution for the aforementioned problems has been found by the present inventors as described herein. In particular, the invention relates to a vinylaromatic polymer composite article comprising (or consisting of):

[0019] (a) at least one segment (a) comprising or consisting of at least one first vinylaromatic polymer composition A, comprising:

[0020] A-1 : 50 to 98 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one vinylaromatic copolymer A-1 , comprising or consisting of: A-11 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic copolymer

[0021] A-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and

[0022] A-12: 0 to 50 wt-%, based on the total weight of the vinylaromatic copolymer A-

[0023] 1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) A-11 ;

[0024] A-2: 2 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one rubbery polymer A-2, dispersed in the vinylaromatic copolymer A-1 ;

[0025] A-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one further polymer; and

[0026] A-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition

[0027] A, of at least one additive, wherein the sum of components A-1 , A-2, A-3 and A-4 is 100 wt.-%;

[0028] (b) at least one segment (b) comprising or consisting of at least one second vinylaromatic polymer composition B, comprising:

[0029] B-1 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one vinylaromatic polymer B-1 , comprising or consisting of: B-11 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic copolymer

[0030] B-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and

[0031] B-12: 0 to 50 wt.-%, based on the total weight of the vinylaromatic copolymer B-

[0032] 1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) B-11 ;

[0033] B-2: 0 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition

[0034] B, of at least one rubbery polymer B-2, dispersed in the vinylaromatic polymer B- 1 ;

[0035] B-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one further polymer; and

[0036] B-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one additive, wherein the sum of components B-1 , B-2, B-3 and B-4 is 100 wt.-%;

[0037] (c) optionally at least one segment (c) comprising or consisting of at least one further vinylaromatic polymer composition C, comprising parts comprising

[0038] C-1 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one vinylaromatic polymer C-1 , comprising or consisting of:

[0039] C-11 : 50 to 100 wt-%, based on the total weight of the vinylaromatic copolymer

[0040] C-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and C-12: 0 to 50 wt-%, based on the total weight of the vinylaromatic copolymer C-

[0041] 1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) C-11 ;

[0042] C-2: 0 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition C, at least one rubbery polymer C-2, dispersed in the vinylaromatic polymer C-1 ;

[0043] C-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one further polymer C-3; and

[0044] C-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one additive C-4, wherein the sum of components C-1 , C-2, C-3 and C-4 is 100 wt.-%; wherein the vinylaromatic polymer composite article is characterized in that the percentages of repeating units A-11 , based on the total weight of the vinylaromatic polymers A-1 , repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 , and optionally repeating units C-11, based on the total weight of the vinylaromatic polymers C-1 , differ from each other by < 25 wt.-%, preferably by < 20 wt.-%, often < 15 wt.-%, for example < 10 wt.-%. This ensures a good compatibility of the polymers A and B and optionally C.

[0045] Accordingly, in one embodiment the percentage of repeating units A-11, based on the total weight of the vinylaromatic polymers A-1 and the percentage of repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 , differ from each other by < 25 wt.-%, for example < 24 wt.-%, < 23 wt.-%, < 22 wt.-%, or < 21 wt.-%, preferably by < 20 wt.-%, for example < 19 wt.-%, < 18 wt.-%, < 17 wt-%, or < 16 wt.-%, often < 15 wt.-%, for example < 12 wt.-% or < 10 wt.-%. In one embodiment, the percentage of repeating units A-11, based on the total weight of the vinylaromatic polymers A-1 and the percentage of repeating units C-11 , based on the total weight of the vinylaromatic polymers C-1 , differ from each other by < 25 wt- %, preferably by < 20 wt.-%, often < 15 wt.-%, for example < 10 wt.-%.

[0046] In one embodiment the percentage of repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 and the percentage of repeating units C-11 , based on the total weight of the vinylaromatic polymers C-1 , differ from each other by < 25 wt-%, for example < 24 wt.-%, < 23 wt.-%, < 22 wt.-%, or < 21 wt.-%, preferably by < 20 wt.-%, for example < 19 wt.-%, < 18 wt.-%, < 17 wt.-%, or < 16 wt.-%, often < 15 wt.-%, for example < 12 wt.-% or < 10 wt.-%. In one embodiment the percentage of repeating units A-11, based on the total weight of the vinylaromatic polymers A-1 , the percentage of repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1, and the percentage of repeating units C-11 , based on the total weight of the vinylaromatic polymers C-1, differ from each other by < 25 wt.-%, for example < 24 wt.-%, < 23 wt.-%, < 22 wt.-%, or < 21 wt.-%, preferably by < 20 wt.-%, for example < 19 wt.-%, < 18 wt.-%, < 17 wt-%, or < 16 wt.-%, often < 15 wt.-%, for example < 12 wt.-% or < 10 wt.-%. In a further aspect, the invention relates to a process for producing a vinylaromatic polymer composite article according to the invention as component of a refrigerating device or a freezing device. In yet another aspect, the invention relates to the use of a vinylaromatic polymer composite article according to the invention as component of a refrigerating device or a freezing device.

[0047] The different aspects of the invention are described in further detail in the following.

[0048] Vinylaromatic polymer composite article

[0049] According to the invention, the vinylaromatic polymer composite article comprising or consisting of:

[0050] (a) at least one segment (a) comprising or consisting of at least one first vinylaromatic polymer composition A,

[0051] (b) at least one segment (b) comprising or consisting of at least one second vinylaromatic polymer composition B, and

[0052] (c) optionally at least one segment (c) comprising or consisting of at least one further vinylaromatic polymer composition C.

[0053] Preferably, the vinylaromatic polymer composite article comprises:

[0054] (a) 20 to 80 wt.-%, preferably 30 to 70 wt.-%, for example 30 to 69 wt.-%, based on the total weight of the vinylaromatic polymer composite article, of the at least one segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;

[0055] (b) 20 to 80 wt.-%, preferably 30 to 70 wt-%, for example 30 to 70 wt.-%, based on the total weight of the vinylaromatic polymer composite article, of the at least one segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and

[0056] (c) 0 to 60 wt.-%, preferably 0 to 40 wt-%, for example 1 to 40 wt.-%, based on the total weight of the vinylaromatic polymer composite article, of the at least one segment (c) of the at least one further vinylaromatic polymer composition C, wherein sum of segments (a), (b) and (c) is 100 wt.-%.

[0057] According to one embodiment of the invention, the vinylaromatic polymer composite article comprises:

[0058] (a) 10 to 80 vol.-%, preferably 10 to 70 vol.-%, based on the total volume of the vinylaromatic polymer composite article, of the at least one segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;

[0059] (b) 20 to 89 vol.-%, preferably 40 to 80 vol.-%, based on the total volume of the vinylaromatic polymer composite article, of the at least one segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and (c) 1 to 70 vol.-%, preferably 10 to 50 vol.-%, based on the total volume of the vinylaromatic polymer composite article, of the at least one segment (c) of the at least one further vinylaromatic polymer composition C.

[0060] According to one embodiment, segment (b) is positioned between segment (a) and segment (c). Segment (b) comprises two opposing surfaces, also referred to as first surface and second surface. Segment (a) is positioned on at least a part of the first surface of segment (b). Segment (c) is positioned on at least a part of the second surface of segment (b). Segment (a) and / or segment (c) may have the same shape and / or size as segment (b). Segment (a) and / or segment (c) may have different shapes and / or sizes as segment (b). Segment (a) may have the same shape and / or size as segment (c). In one embodiment, segment (a) and / or segment (c) have a larger size than segment (b). In one embodiment, segment (a) and segment (c) are in contact with each other at at least some sections which extent beyond the shape of segment (b). This allows to encase segment (b) by segments (a) and (c).

[0061] Preferably, the vinylaromatic polymer composite article comprises at least two segments (a), (b) and optionally (c), which have a different chemical composition. For example, segment (a) and segment (b) have a different chemical composition. In one embodiment, the vinylaromatic polymer composite article comprises at least three segments (a), (b) and (c), wherein segment (a) is different from segment (b) with regards to their chemical composition and segment (b) is different from segment (c) with regards to their chemical composition. Segment (a) and segment (c) may have the same chemical composition or may be different with regards to their chemical composition. For example, segment (a) and segment (c) have the same chemical composition and segment (b) has a chemical composition different from segments (a) and (c).

[0062] According to the invention, the terms “different chemical composition” or “different with regards to their chemical composition” refer to vinylaromatic polymer compositions A, B and / or C, which differ at least in one of the constituents A-1 , A-2, A-3, A-4, B-1 , B-2, B-3, B-4, C-1 , C-2, C-3, and / or C-4. For example, the vinylaromatic polymer compositions A, B and / or C may differ in the monomers of which they are composed, the vinylaromatic polymer compositions A, B and / or C may differ in the ratios of comonomers of which they are composed, the vinylaromatic polymer compositions A, B and / or C may differ in the selection or ratio of the polymer constituents A-1 , A-2, A-3, B-1 , B-2, B-3, C-1 , C-2, and / or C-3 of which they are composed, or the vinylaromatic polymer compositions A, B and / or C may differ in the selection or ratio of the additives A-4, B-4, and / or C-4.

[0063] According to one embodiment of the invention, at least one of the segments (a), (b) and / or (c) is (at least partially) configured in the shape of a polymer foam, preferably the at least one segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B is (at least partially) configured in the shape of a polymer foam. Polymer foams are known in the art and may be produced by known processes. According to one embodiment, the vinylaromatic polymer composition to be foamed (i.e. A, B, or C) is impregnated with at least one physical foaming agent (as additive B-4) and subsequently foamed by reducing the ambient pressure and / or increasing the ambient temperature. In an alternative embodiment, the vinylaromatic polymer composition to be foamed (i.e. A, B, or C) is mixed with at least one chemical foaming agent (as additive B-4) and subsequently foamed by increasing the ambient temperature in order to effect the decomposition of the chemical foaming agent. Foaming may be facilitated by reducing the ambient pressure, e.g. to a pressure at least 200 mbar below the ambient pressure. Physical and chemical foaming agents may also be used in combination with each other as additive B-4.

[0064] Suitable physical foaming agents include gases like carbon dioxide, nitrogen, noble gases or mixtures thereof, preferably carbon dioxide, nitrogen and mixtures thereof. Further suitable physical foaming agents include lower hydrocarbons, for example Ci-Ce alkanes, in particular butane and pentane. Suitable chemical foaming agents may, for example, be a mixture of sodium bicarbonate and citric acid or carbodiimide. Preferably, the foaming agent is not a fluorinated foaming agent, more preferably not a halogenated foaming agent.

[0065] In one embodiment, the vinylaromatic polymer composite article is a layered vinylaromatic polymer composite article comprising:

[0066] (a) at least one layered segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;

[0067] (b) at least one layered segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and

[0068] (c) optionally at least one layered segment (c) comprising or consisting of the at least one further vinylaromatic polymer composition C.

[0069] The layered segments may be obtained by thermoforming the respective vinylaromatic polymer compositions A, B, and optionally C. Accordingly, in one embodiment, the vinylaromatic polymer composite article is a layered vinylaromatic polymer composite article comprising:

[0070] (a) at least one thermoformed layered segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;

[0071] (b) at least one foamed layered segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and

[0072] (c) optionally at least one further layered segment (c) comprising or consisting of the at least one further vinylaromatic polymer composition C.

[0073] According to one embodiment, the at least one thermoformed layered segment (a) is a thermoformed refrigerator liner and the at least one foamed layered segment (b) is a refrigerator insulation foam.

[0074] Preferably, the thermoformed layered segment (a) is a thermoformed refrigerator liner having a thickness of < 10 mm, often < 8 mm, for example from 0.5 to 8 mm, often from 1 to 6 mm. In one embodiment, the thermoformed layered segment (b) has a thickness of < 10 mm, often

[0075] < 8 mm, for example from 0.5 to 8 mm, often from 1 to 6 mm. In one embodiment, the thermoformed layered segment (b) is a foamed insulation layer having a thickness of 5 to 100 mm, often 10 to 80 mm, for example from 15 to 60 mm.

[0076] In one embodiment, the thermoformed layered segment (c) has a thickness of < 10 mm, often

[0077] < 8 mm, for example from 0.5 to 8 mm, often from 1 to 6 mm.

[0078] According to one embodiment, the first vinylaromatic polymer composition A may comprise at least one further polymer A-3, the second vinylaromatic polymer composition B may comprise at least one further polymer B-3, and the optional further vinylaromatic polymer composition C may comprise at least one further polymer C3. Preferably, the optional polymers A-3, B-3 and C-3 are each independently selected from vinylaromatic polymers. The optional polymers A- 3, B-3 and C-3 are different form the vinylaromatic polymers A-1, B-1 and C-1, respectively. Often, the first vinylaromatic polymer composition A does not comprise a further polymer A-3. Often, the second vinylaromatic polymer composition B does not comprise a further polymer B-3. Often, the optional further vinylaromatic polymer composition C does not comprise a further polymer C3.

[0079] In a preferred embodiment, the first vinylaromatic polymer composition A consists of the constituents A-1 , A-2 and optionally A-4. Preferably, the second vinylaromatic polymer composition B consists of the constituents B-1 , B-2 and optionally B-4. In a further preferred embodiment, the at least one further vinylaromatic polymer composition C consists of the constituents C-1 , C-2 and optionally C-4.

[0080] According to one embodiment of the invention, melt blending of constituents A-1 and A-2 with constituents B-1 and B-2 and optionally with constituents C-1 and C-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single-phase morphology or a 2-phase morphology having an average domain size of less than 20 pm, preferably less than 15 pm, often less than 12 pm. It is understood that melt blending of the constituents requires a temperature, which allows to obtain a substantially liquid melt of the polymer constituents, i.e. a temperature above the melt temperature of the polymer constituents.

[0081] This indicates a good compatibility of the respective constituents and common recyclability of the mixture. In one embodiment, melt blending of constituents A-1 and A-2 with constituents B-1 and B-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single phase morphology or a 2-phase morphology having an average domain size of less than 20 pm, preferably less than 15 pm, often less than 12 pm. In one embodiment, melt blending of constituents A-1 and A-2 with constituents C-1 and C-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single phase morphology or a 2-phase morphology having an average domain size of less than 20 m, preferably less than 15 pm, often less than 12 pm. In one embodiment, melt blending of constituents B-1 and B-2 with constituents C-1 and C-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single phase morphology or a 2-phase morphology having an average domain size of less than 20 pm, preferably less than 15 pm, often less than 12 pm.

[0082] In one embodiment, melt blending of constituents A-1 and A-2 with constituents B-1 and B-2 and constituents C-1 and C-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single phase morphology or a 2-phase morphology having an average domain size of less than 20 pm, preferably less than 15 pm, often less than 12 pm.

[0083] According to the invention, the vinylaromatic polymer composite article comprises further segments (c’), (c”), and so on, which are defined as segment (c) described herein.

[0084] Vinylaromatic copolymers A-1 , B-1 and C-1

[0085] According to the invention, the at least one segment (a) of the vinylaromatic polymer composite article comprises or consists of at least one first vinylaromatic polymer composition A, comprising:

[0086] A-1 : 50 to 98 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one vinylaromatic copolymer A-1 , comprising or consisting of:

[0087] A-11 : 50 to 100 wt.-%, preferably 70 to 100 wt.-%, for example 80 to 100 wt.-% or 75 to 95 wt.-%, based on the total weight of the vinylaromatic copolymer A-1, of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and

[0088] A-12: 0 to 50 wt-%, preferably 0 to 30 wt-%, for example 0 to 20 wt-% or 5 to 25 wt-

[0089] %, based on the total weight of the vinylaromatic copolymer A-1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) A-11 ; wherein the sum of components A-11 and A-12 is 100 wt.-%.

[0090] Preferably, the monomers A-11 are selected from styrene, alpha-methylstyrene, and mixtures thereof. Particular preferred is styrene.

[0091] Suitable comonomers A-12 include monomers selected from the group consisting of Ci-Cs alkyl(meth)acrylate (preferably C1-C4 alkyl(meth)acrylate, e.g. methyl methacrylate or ethyl methacrylate), acrylonitrile, methacrylonitrile, acrylamide, vinlymethyl ether, anhydrides of unsaturated carboxylic acids (e.g. maleic anhydride or phthalic acid anhydride) and imides of unsaturated carboxylic acids (e.g. N-substituted maleimides, like N-cyclohexylmaleimide or N- phenylmaleimide). Preferred are methyl methacrylate, ethyl methacrylate, acrylonitrile, methacrylonitrile, in particular acrylonitrile.

[0092] According to the invention, the at least one segment (b) of the vinylaromatic polymer composite article comprises or consists of at least one second vinylaromatic polymer composition B, comprising:

[0093] B-1 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one vinylaromatic polymer B-1 , comprising or consisting of:

[0094] B-11: 50 to 100 wt.-%, preferably 70 to 100 wt.-%, for example 80 to 100 wt.-% or 75 to 95 wt.-%, based on the total weight of the vinylaromatic copolymer B-1, of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and

[0095] B-12: 0 to 50 wt.-%, preferably 0 to 30 wt-%, for example 0 to 20 wt-% or 5 to 25 wt- %, based on the total weight of the vinylaromatic copolymer B-1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) B-11 ; wherein the sum of components B-11 and B-12 is 100 wt.-%.

[0096] Preferably, the monomers B-11 are selected from styrene, alpha-methylstyrene, and mixtures thereof. Particular preferred is styrene.

[0097] Suitable comonomers B-12 include monomers selected from the group consisting of Ci-Cs alkyl(meth)acrylate (preferably C1-C4 alkyl(meth)acrylate, e.g. methyl methacrylate or ethyl methacrylate), acrylonitrile, methacrylonitrile, acrylamide, vinlymethyl ether, anhydrides of unsaturated carboxylic acids (e.g. maleic anhydride or phthalic acid anhydride) and imides of unsaturated carboxylic acids (e.g. N-substituted maleimides, like N-cyclohexylmaleimide or N- phenylmaleimide). Preferred are methyl methacrylate, ethyl methacrylate, acrylonitrile, methacrylonitrile, in particular acrylonitrile.

[0098] According to the invention, the at least one segment (c) of the vinylaromatic polymer composite article comprises or consists of at least one second vinylaromatic polymer composition C, comprising:

[0099] C-1 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one vinylaromatic polymer C-1 , comprising or consisting of:

[0100] C-11 : 50 to 100 wt.-%, preferably 70 to 100 wt.-%, for example 80 to 100 wt.-% or 75 to 95 wt.-%, based on the total weight of the vinylaromatic copolymer C-1, of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; and

[0101] C-12: 0 to 50 wt.-%, preferably 0 to 30 wt.-%, for example 0 to 20 wt.-% or 5 to 25 wt.- %, based on the total weight of the vinylaromatic copolymer C-1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) C-11 ; wherein the sum of components C-11 and C-12 is 100 wt.-%.

[0102] Preferably, the monomers C-11 are selected from styrene, alpha-methylstyrene, and mixtures thereof. Particular preferred is styrene.

[0103] Suitable comonomers C-12 include monomers selected from the group consisting of Ci-Cs alkyl(meth)acrylate (preferably C1-C4 alkyl(meth)acrylate, e.g. methyl methacrylate or ethyl methacrylate), acrylonitrile, methacrylonitrile, acrylamide, vinlymethyl ether, anhydrides of unsaturated carboxylic acids (e.g. maleic anhydride or phthalic acid anhydride) and imides of unsaturated carboxylic acids (e.g. N-substituted maleimides, like N-cyclohexylmaleimide or N- phenylmaleimide). Preferred are methyl methacrylate, ethyl methacrylate, acrylonitrile, methacrylonitrile, in particular acrylonitrile.

[0104] According to the invention, the amounts of monomers A-11, B-11 and - if present - C-11 are selected in that the percentages of repeating units A-11 , based on the total weight of the vi- nylaromatic polymers A-1 , repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 , and optionally repeating units C-11 , based on the total weight of the vinylaromatic polymers C-1 , differ from each other by < 25 wt.-%, preferably by < 20 wt.-%, often < 15 wt.-%, for example < 10 wt.-%.

[0105] Optional rubbery polymers A-2, B-2, and C-2

[0106] According to the invention, the at least one segment (a) of the vinylaromatic polymer composite article comprises or consists of at least one first vinylaromatic polymer composition A, comprising:

[0107] A-2: 2 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one rubbery polymer A-2, dispersed in the vinylaromatic copolymer A-1.

[0108] Preferably, the rubbery polymer A-2 comprises or consists of:

[0109] A-21 : rubber obtained by a emulsion polymerization reaction; and / or

[0110] A-22: rubber obtained by a solution polymerization reaction, and / or

[0111] A-23: rubber obtained by a mass polymerization reaction; and / or

[0112] A-24: rubber obtained by an anionic and / or living polymerization reaction.

[0113] Each of the rubbers A-21 , A-22, A-23 and A-24 preferably comprises butadiene, isoprene and / or acrylate. In one embodiment, the rubbers A-21 , A-22, A-23 and A-24, respectively, comprise at least one monomer selected from acrylonitrile, methacrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore mentioned.

[0114] In one embodiment, the rubbers A-21 , A-22, A-23 and A-24, respectively, comprise at least one monomer selected from acrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, and mixtures thereof, preferably acrylonitrile and styrene.

[0115] In one embodiment, the rubbers A-21 , A-22, A-23 and A-24, respectively, comprise at least one monomer selected from vinylaromatic monomers, preferably selected from styrene, alphamethylstyrene, and mixtures thereof, in particular styrene.

[0116] According to one embodiment, the rubbers A-21 , A-22, A-23 and A-24, respectively, are graft / shell copolymers which are compatible with component A-1, preferably the rubber A-21 is a graft / shell copolymer which is compatible with component A-1.

[0117] Suitable rubbers include acrylonitrile-butadiene-styrene copolymers (ABS), acrylonitrile-sty- rene-acrylate copolymers (ASA), and styrene-butadiene copolymers (SBC),

[0118] Acrylonitrile-butadiene-styrene copolymers (ABS) are graft copolymers known in the art and consist of a graft core comprising repeating units of butadiene and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ABS is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component A-1. Preferably, the ABS and SAN are mixed.

[0119] Acrylonitrile-styrene-acrylate copolymers (ASA) are graft copolymers known in the art and consist of a graft core comprising repeating units of acrylates, preferably Ci-Cs alkyl(meth)acrylate (e.g. n-butylacrylate) and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ASA is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component A-1 . Preferably, the ASA and SAN are mixed.

[0120] Styrene-butadiene copolymers (SBC) are block copolymer known in the art and consists of at least one soft polymer block B, which predominantly comprises repeating units of butadiene and at least one hard polymer block S which predominantly comprises or consists of repeating units of styrene. In one embodiment, the SBC comprises a triblock structure SBS. SBC is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component A- 1. Preferably, the SBC and SAN are mixed. In an alternative embodiment, the rubbers A-21 , A-22, A-23 and A-21, respectively, comprise polybutadiene rubber particles (BR). BR is preferably used in combination with styrene homopolymers. Preferably, styrene monomers are polymerized in the presence of BR particles, and optionally mixed with further styrene homopolymers. The resulting composition is known in the art as high impact polystyrene (HIPS).

[0121] The rubbers A-21 , A-22, A-23 and / or A-24 optionally create lamellae, cylinders, spheres, and / or bi-continuous morphologies.

[0122] The rubbers A-21 , A-22, A-23 and A-24, respectively, may be mixed with the further constituents A-1 and optionally A-3 and A-4.

[0123] Alternatively, the rubbers A-21, A-22, A-23 and A-24, respectively, can be mixed with the monomers of A-1, which are subsequently polymerized in the presence of the rubbers A-21 , A-22, A-23 and A-24, respectively.

[0124] According to the invention, the at least one segment (b) of the vinylaromatic polymer composite article comprises or consists of at least one second vinylaromatic polymer composition B, comprising:

[0125] B-2: 2 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one rubbery polymer B-2, dispersed in the vinylaromatic copolymer B-1.

[0126] Preferably, the rubbery polymer B-2 comprises or consists of:

[0127] B-21 : rubber obtained by an emulsion polymerization reaction; and / or

[0128] B-22: rubber obtained by a solution polymerization reaction, and / or

[0129] B-23: rubber obtained by a mass polymerization reaction; and / or

[0130] B-24: rubber obtained by an anionic and / or living polymerization reaction.

[0131] Each of the rubbers B-21 , B-22, B-23 and B-24 preferably comprise butadiene, isoprene and / or acrylate.

[0132] In one embodiment, the rubbers B-21, B-22, B-23 and B-24, respectively comprise at least one monomer selected from acrylonitrile, methacrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore mentioned.

[0133] In one embodiment, the rubbers B-21 , B-22, B-23 and B-24, respectively, comprise at least one monomer selected from acrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, and mixtures thereof, preferably acrylonitrile and styrene. In one embodiment, the rubbers B-21 , B-22, B-23 and B-24, respectively, comprise at least one monomer selected from vinylaromatic monomers, preferably selected from styrene, alphamethylstyrene, and mixtures thereof, in particular styrene.

[0134] According to one embodiment, the rubbers B-21 , B-22, B-23 and B-24, respectively, are graft / shell copolymers which are compatible with component B-1, preferably the rubber B-21 is a graft / shell copolymer which is compatible with component B-1.

[0135] Suitable rubbers include acrylonitrile-butadiene-styrene copolymers (ABS), acrylonitrile-sty- rene-acrylate copolymers (ASA), styrene-butadiene copolymers (SBC).

[0136] Acrylonitrile-butadiene-styrene copolymers (ABS) are graft copolymers known in the art and consist of a graft core comprising repeating units of butadiene and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ABS is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component B-1. Preferably, the ABS and SAN are mixed.

[0137] Acrylonitrile-styrene-acrylate copolymers (ASA) are graft copolymers known in the art and consist of a graft core comprising repeating units of acrylates, preferably Ci-Cs alkyl(meth)acrylate (e.g. n-butylacrylate) and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ASA is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component B-1 . Preferably, the ASA and SAN are mixed.

[0138] Styrene-butadiene copolymers (SBC) are block copolymer known in the art and consists of at least one soft polymer block B, which predominantly comprises repeating units of butadiene and at least one hard polymer block S which predominantly comprises repeating units of styrene. In one embodiment, the SBC comprises a triblock structure SBS. SBC is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component B-1. Preferably, the SBC and SAN are mixed.

[0139] In an alternative embodiment, the rubbers B-21 , B-22, B-23 and B-21, respectively, comprise polybutadiene rubber particles (BR). BR is preferably used in combination with styrene homopolymers. Preferably, styrene monomers are polymerized in the presence of BR particles, and optionally mixed with further styrene homopolymers. The resulting composition is known in the art as high impact polystyrene (HIPS).

[0140] The rubbers B-21 , B-22, B-23 and / or B-24 optionally create lamellae, cylinders, spheres, and / or bi-continuous morphologies. The rubbers B-21 , B-22, B-23 and B-24, respectively, may be mixed with the further constituents B-1 and optionally B-3 and B-4.

[0141] Alternatively, the rubbers B-21, B-22, B-23 and B-24, respectively, can be mixed with the monomers of B-1, which are subsequently polymerized in the presence of the rubbers B-21 , B-22, B-23 and B-24, respectively.

[0142] According to the invention, the at least one segment (c) of the vinylaromatic polymer composite article comprises or consists of at least one further vinylaromatic polymer composition C, comprising:

[0143] C-2: 2 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one rubbery polymer C-2, dispersed in the vinylaromatic copolymer C-1.

[0144] Preferably, the rubbery polymer C-2 comprises or consists of:

[0145] C-21 : rubber obtained by a emulsion polymerization reaction; and / or

[0146] C-22: rubber obtained by a solution polymerization reaction, and / or

[0147] C-23: rubber obtained by a mass polymerization reaction; and / or

[0148] C-24: rubber obtained by an anionic and / or living polymerization reaction.

[0149] Each of the rubbers C-21, C-22, C-23 and C-24 preferably comprise butadiene, isoprene and / or acrylate.

[0150] In one embodiment, the rubbers C-21, C-22, C-23 and C-24, respectively comprise at least one monomer selected from acrylonitrile, methacrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore mentioned.

[0151] In one embodiment, the rubbers C-21 , C-22, C-23 and C-24, respectively, comprise at least one monomer selected from acrylonitrile and vinylaromatic monomers, preferably selected from styrene, alpha-methylstyrene, and mixtures thereof, preferably acrylonitrile and styrene.

[0152] In one embodiment, the rubbers C-21 , C-22, C-23 and C-24, respectively, comprise at least one monomer selected from vinylaromatic monomers, preferably selected from styrene, alphamethylstyrene, and mixtures thereof, in particular styrene.

[0153] According to one embodiment, the rubbers C-21, C-22, C-23 and C-24, respectively, are graft / shell copolymers which are compatible with component C-1 , preferably the rubber C-21 is a graft / shell copolymer which is compatible with component C-1 .

[0154] Suitable rubbers include acrylonitrile-butadiene-styrene copolymers (ABS), acrylonitrile-sty- rene-acrylate copolymers (ASA), styrene-butadiene copolymers (SBC), Acrylonitrile-butadiene-styrene copolymers (ABS) are graft copolymers known in the art and consist of a graft core comprising repeating units of butadiene and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ABS is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component C-1. Preferably, the ABS and SAN are mixed.

[0155] Acrylonitrile-styrene-acrylate copolymers (ASA) are graft copolymers known in the art and consist of a graft core comprising repeating units of acrylates, preferably Ci-Ca alkyl(meth)acrylate (e.g. n-butylacrylate) and optionally styrene and at least one graft shell comprising styrene and acrylonitrile, which is obtained by graft copolymerization of the styrene and acrylonitrile in the presence of the graft core. ASA is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component C-1 . Preferably, the ASA and SAN are mixed.

[0156] Styrene-butadiene copolymers (SBC) are block copolymer known in the art and consists of at least one soft polymer block B, which predominantly comprises repeating units of butadiene and at least one hard polymer block S which predominantly comprises repeating units of styrene. In one embodiment, the SBC comprises a triblock structure SBS. SBC is preferably used in combination with styrene-acrylonitrile copolymers (SAN) as component C-1. Preferably, the SBC and SAN are mixed.

[0157] In an alternative embodiment, the rubbers C-21, C-22, C-23 and C-21 , respectively, comprise polybutadiene rubber particles (BR). BR is preferably used in combination with styrene homopolymers. Preferably, styrene monomers are polymerized in the presence of BR particles, and optionally mixed with further styrene homopolymers. The resulting composition is known in the art as high impact polystyrene (HIPS).

[0158] The rubbers C-21 , C-22, C-23 and / or C-24 optionally create lamellae, cylinders, spheres, and / or bi-continuous morphologies.

[0159] The rubbers C-21 , C-22, C-23 and C-24, respectively, may be mixed with the further constituents C-1 and optionally C-3 and C-4.

[0160] Alternatively, the rubbers C-21 , C-22, C-23 and C-24, respectively, can be mixed with the monomers of C-1 , which are subsequently polymerized in the presence of the rubbers C-21 , C-22, C-23 and C-24, respectively.

[0161] Optional further polymers A-3, B-3, and C-3

[0162] According to the invention, the at least one segment (a) of the vinylaromatic polymer composite article comprises or consists of at least one first vinylaromatic polymer composition A, optionally comprising up to 48 wt.-%, preferably up to 38 wt.-%, more preferably up to 23 wt.-%, for example up to 13 wt.-%, based on the total weight of the vinylaromatic polymer composition

[0163] A, of at least one further polymer as component A-3. The polymer A-3 may be selected from thermoplastic homopolymers or copolymers, which are compatible with the vinylaromatic copolymer A-1 , such as polycarbonates, polyamides, or vinylaromatic (co)polymers different from the vinylaromatic copolymer A-1 and the rubbery polymer A-2. If present, the polymer A-3 is preferably a vinylaromatic (co)polymer such as polystyrene, poly(alpha-methyl styrene), poly(styrene methyl methacrylate), or poly(styrene acrylonitrile). However, in a preferred embodiment, the at least one first vinylaromatic polymer composition A does not comprise a further polymer A-3.

[0164] According to the invention, the at least one segment (b) of the vinylaromatic polymer composite article comprises or consists of at least one first vinylaromatic polymer composition B, optionally comprising up to 48 wt.-%, preferably up to 38 wt.-%, more preferably up to 23 wt.-%, for example up to 13 wt.-%, based on the total weight of the vinylaromatic polymer composition

[0165] B, of at least one further polymer as component B-3. The polymer B-3 may be selected from thermoplastic homopolymers or copolymers, which are compatible with the vinylaromatic copolymer B-1 , such as polycarbonates, polyamides, or vinylaromatic (co)polymers different from the vinylaromatic copolymer B-1 and the rubbery polymer B-2. If present, the polymer B-3 is preferably a vinylaromatic (co)polymer such as polystyrene, poly(alpha-methyl styrene), poly(styrene methyl methacrylate), or poly(styrene acrylonitrile). However, in a preferred embodiment, the at least one first vinylaromatic polymer composition B does not comprise a further polymer B-3.

[0166] According to the invention, the optional segment (c) of the vinylaromatic polymer composite article comprises or consists of at least one vinylaromatic polymer composition C, optionally comprising up to 48 wt-%, preferably up to 38 wt.-%, more preferably up to 23 wt.-%, for example up to 13 wt-%, based on the total weight of the vinylaromatic polymer composition

[0167] C, of at least one further polymer as component C-3. The polymer C-3 may be selected from thermoplastic homopolymers or copolymers, which are compatible with the vinylaromatic copolymer C-1 , such as polycarbonates, polyamides, or vinylaromatic (co)polymers different from the vinylaromatic copolymer C-1 and the rubbery polymer C-2. If present, the polymer C-3 is preferably a vinylaromatic (co)polymer such as polystyrene, poly(alpha-methyl styrene), poly(styrene methyl methacrylate), or poly(styrene acrylonitrile). However, in a preferred embodiment, the at least one first vinylaromatic polymer composition C does not comprise a further polymer C-3.

[0168] Additives A-4, B-4 and C-4

[0169] According to the invention, the vinylaromatic polymer composition A may comprise 0 to 20 wt.- %, preferably 0 to 10 % by weight, preferably 0 to 5 % by weight, often 0.1 to 5 %, based on the vinylaromatic polymer composition A, of one or more additive A-4. More preferably, the at least one additive A-4 is present in an amount of 0.001 to 10 % by weight, more preferably 0.01 to 5 % by weight, based on the vinylaromatic polymer composition A. In particular, the additive A-4 is not a polymeric compound defined as components A-1 , A-2 or A-3.

[0170] According to the invention, the vinylaromatic polymer composition B may comprise 0 to 20 wt- %, preferably 0 to 10 % by weight, preferably 0 to 5 % by weight, often 0.1 to 5 %, based on the vinylaromatic polymer composition B, of one or more additive B-4. More preferably the at least one additive B-4 is present in an amount of 0.001 to 10 % by weight, more preferably 0.01 to 5 % by weight, based on the vinylaromatic polymer composition B. In particular, the additive B-4 is not a polymeric compound defined as components B-1 , B-2 or B-3.

[0171] According to the invention, the vinylaromatic polymer composition C may comprise 0 to 20 wt- %, preferably 0 to 10 % by weight, preferably 0 to 5 % by weight, often 0.1 to 5 %, based on the vinylaromatic polymer composition C, of one or more additive C-4. More preferably the at least one additive C-4 is present in an amount of 0.001 to 10 % by weight, more preferably 0.01 to 5 % by weight, based on the vinylaromatic polymer composition C. In particular, the additive C-4 is not a polymeric compound defined as components C-1 , C-2 or C-3.

[0172] The optional additive A-4, B-4, and - if present - C-4 may be selected from commonly known additives and / or auxiliaries for plastic materials. With respect to conventional auxiliaries and additives, reference is made by way of example to “Plastics Additives Handbook”, Hans Zweifel 6th Edition, Hanser Publ., Munich, 2009. For example the at least one additive K may be selected from fillers, reinforcing agents, dyes, pigments, lubricants or mold-release agents, processing aids stabilizers, in particular light and heat stabilizers, antioxidants, UV absorbers, plasticizers, impact modifiers, antistatic agents, flame retardants, bactericides, fungicides, optical brighteners, and blowing agents.

[0173] The optional additive A-4, B-4, and - if present - C-4 is preferably selected from foaming agents, dyes, pigments, lubricants or mold-release agents, processing aids, stabilizers, in particular foaming agents, processing aids, antistatic agents, flame retardants and fillers.

[0174] Suitable foaming agents least include physical foaming agents, chemical foaming agent and mixtures thereof. Suitable physical foaming agents include gases like carbon dioxide, nitrogen, noble gases or mixtures thereof, preferably carbon dioxide, nitrogen and mixtures thereof. Further suitable physical foaming agents include lower hydrocarbons, for example Ci-Ce alkanes, in particular butane and pentane. Suitable chemical foaming agents may, for example, be a mixture of sodium bicarbonate and citric acid or carbodiimide. Preferably, the foaming agent is not a fluorinated foaming agent, more preferably not a halogenated foaming agent. In a preferred embodiment, the additive(s) B-4 include at least one foaming agent.

[0175] Examples that may be mentioned as fillers, which may be selected from particulate fillers or reinforcing agents, are silicates, amorphous silica, calcium silicates, such as wollastonite, powdered quartz, mica, metal oxides, metal hydroxides, carbon black, graphite, barium sulfate, calcium carbonate, magnesium carbonate, bentonites, talc, kaolin, carbon fibers or glass fibers in the form of glass woven, glass mats, or glass silk rovings, chopped glass, or glass beads. In particular at least one particulate fillers, preferably a mineral filler, can be used as additive A-4, B-4, and - if present - C-4.

[0176] Common stabilizers for thermoplastic polymers encompass stabilizers for improving thermal stability, which are commonly agents to counteract thermal decomposition, light stabilizers (stabilizers for increasing lightfastness), and stabilizers for raising resistance to hydrolysis and to chemicals. Examples of suitable light stabilizers are various substituted resorcinols, salicylates, benzotriazoles, and benzophenones.

[0177] Examples of suitable stabilizers are hindered phenols, but also vitamin E and compounds whose structure is analogous thereto. HALS stabilizers (Hindered Amine Light Stabilizers), benzophenones, resorcinols, salicylates, and benzotriazoles are also suitable.

[0178] Suitable lubricants or mold-release agents are fatty acids having from 12 to 30 carbon atoms, salts and derivatives thereof, for example stearic acid and stearates, palmitic acid and palmitates, stearyl alcohol, stearic esters, amide waxes (e.g. stearamides, in particular ethylene bis(stearamide) (EBS)), and polyolefin waxes. Particularly suitable lubricants and moldrelease agents are stearic acid, stearates (e.g. magnesium stearate), palmitic acid, palmitates (e.g. sodium palmitate), ethylene bis(stearamide) (e.g. Irgawax®, Ciba, Switzerland) and mixtures thereof.

[0179] In particular, the vinylaromatic polymer composition A, B, and C, respectively, can optionally comprise at least one common processing aid, e.g. selected from lubricants, mold release agents and antistatic agents. An example of a processing aid is a homogeneously miscible oil or oil mixture, in particular selected from mineral oils (medical grade mineral oil), vegetable oils (also referred to as plant oils) and silicon oils. In particular, medical grade mineral oil (e.bg. DAB 70) may be used as additive A-4, B-4, and - if present - C-4.

[0180] Preferably, the vinylaromatic polymer composition A, B, and C, respectively, can optionally comprise at least one pigment and / or colorant, in particular selected from titanium dioxide, phthalocyanines, ultramarine blue, iron oxides, or carbon black, and also the entire class of organic pigments.

[0181] Preferably, the additives A-4 are selected from of the group consisting of stabilizers, processing aids (e.g. mineral oils), mineral fillers, glass fibers, carbon fibers, and mixtures of at least two of the afore-mentioned, as defined herein. Preferably, the additives B-4 are selected from of the group consisting of foaming agents, stabilizers, processing aids (e.g. mineral oils), mineral fillers, glass fibers, carbon fibers, and mixtures of at least two of the afore-mentioned, more preferably selected from stabilizers, mineral fillers, and mixtures thereof, as defined herein.

[0182] Preferably, the additives C-4 are selected from of the group consisting of stabilizers, processing aids (e.g. mineral oils), mineral fillers, glass fibers, carbon fibers, and mixtures of at least two of the afore-mentioned, as defined herein.

[0183] Process for producing the vinylaromatic polymer composite article

[0184] In a further aspect, the present invention relates to a process for producing a polymer composite article according to the invention comprising at least the following process steps:

[0185] (i) providing at least one thermoformed layered segment (a) comprising or consisting of the at least one first styrenic polymer composition A;

[0186] (ii) providing at least one layered segment (b) comprising or consisting of the at least one second styrenic polymer composition B on at least a part of at least one surface of the thermoformed layered segment (a) provided in process step (i) to obtain a first laminate structure (I); and

[0187] (iii) optionally providing at least one further layered segment (c) comprising or consisting of the at least one further styrenic polymer composition C on at least a part of at least one surface of the first laminate structure (I) obtained in process step (ii) to obtain a second laminate structure (II).

[0188] Preferably, segment (b) is at least partially foamed, i.e. comprises a polymer foam comprising or consisting of the at least one second styrenic polymer composition B.

[0189] Preferably, segment (c), if present, is positioned adjacent to segment (b).

[0190] According to one embodiment, segment (b) is positioned between segment (a) and segment (c). Segment (b) comprises two opposing surfaces, also referred to as first surface and second surface. Segment (a) is positioned on at least a part of the first surface of segment (b). Segment (c) is positioned on at least a part of the second surface of segment (b). Segment (a) and / or segment (c) may have the same shape and / or size as segment (b). Segment (a) and / or segment (c) may have the different shapes and / or sizes as segment (b). Segment (a) may have the same shape and / or size as segment (c). In one embodiment, segment (a) and / or segment (c) have a larger size than segment (b), in one embodiment, segment (a) and segment (c) are in contact with each other at least some sections which extent beyond the shape of segment (b). This allows to encase segment (b) by segments (a) and (c). Composite articles according to the invention may be produced by any process known in the art, which is suitable for the manufacture of polymer composite articles. Preferably, the composite articles can be produced by co-extrusion of the different vinylaromatic polymer compositions A and B (and optionally further vinylaromatic polymer compositions).

[0191] Each of the different vinylaromatic polymer compositions A and B (and optionally further vinylaromatic polymer compositions) - as far as solid - may be provided in form of particulate materials having different particle sizes and particle size distributions (e.g. as pellets, granules and / or powders). Optionally, a step in which a homogenous particulate material mixture is prepared from the constituents may be carried out prior to step (i). In a preferred embodiment, this may require 1 to 60, preferably 1 to 20, in particular 2 to 10 minutes, depending to the amount of particulate material to be mixed.

[0192] Within the meaning of the invention, the term co-extrusion refers to a process wherein substantially melt-liquid vinylaromatic polymer compositions are separately provided and then the obtained polymer melts are extruded together using a co-extrusion die.

[0193] “Substantially melt-liquid” means that the polymer mixture, as well as the predominant meltliquid (softened) fraction, may further comprise a certain fraction of solid constituents, examples being unmolten fillers and reinforcing material such as glass fibers, metal flakes, or else unmolten pigments, colorants, etc. “Melt-liquid” means that the polymer mixture is at least of low fluidity, therefore having softened at least to an extent that it has plastic properties.

[0194] According to one embodiment, the constituents of the vinylaromatic polymer compositions (A) and (B) (and optionally vinylaromatic polymer composition (C) or further compositions) are provided in the predetermined amounts to an optionally heatable mixing device, separately for each vinylaromatic polymer composition. Subsequently, the constituents for each vinylaromatic polymer composition (A), (B), and optionally (C) are blended in the optionally heatable mixing device at temperatures above the glass transition point of the polymer constituents to obtain homogenous, substantially melt-liquid polymer melts of the vinylaromatic polymer compositions separately.

[0195] Suitable blending processes are those known by the person skilled in the art and include, for example, joint extrusion, kneading, or rolling. A preferred mixing apparatus used is an extruder or a kneader. Particularly suitable for melt extrusion are, for example, single-screw or twin- screw extruders. A twin-screw extruder is preferred. In some cases, the mechanical energy introduced by the mixing apparatus in the course of mixing is enough to cause the mixture to melt, meaning that the mixing apparatus does not have to be heated. Otherwise, the mixing apparatus is generally heated. The temperature for blending and extrusion is guided by the chemical and physical properties of the vinylaromatic polymer compositions and should be selected such as to result in a substantially melt-liquid polymer mixture. On the other hand, the temperature is not to be unnecessarily high, in order to prevent thermal damage of the polymer mixture. The mechanical energy introduced may, however, also be high enough that the mixing apparatus may even require cooling. Mixing apparatus is operated customarily at 150 to 400 °C, preferably 170 to 300 °C. Extrusion of the polymer melt is typically made in the same temperature ranges.

[0196] The obtained melt-liquid vinylaromatic polymer compositions are subsequently fed together in a co-extrusion die, resulting in co-extrusion layers (“layered segment” in the sense mentioned above). Subsequent cooling of the co-extrusion layers to temperatures below the glass transition point of the constituents provides the vinylaromatic polymer composite article according to the invention. Cooling of the co-extrusion layers may be achieved with the help of calendar rolls, and / or by air or other means.

[0197] The described process is suitable for the manufacture of dual-layer composite articles as well as multi-layer composite articles. Multi-layer composite articles may be obtained in one single co-extrusion process, or in repeated extrusion processes (e.g. in an over-molding process).

[0198] In one embodiment (e.g. in a process for co-extrusion of thin multilayer composite films), the extrusion setup contains a ring-shaped co-extrusion die and the molten co-extruded multilayer composite leaves the co-extrusion die in form of a ring-shaped tube. In one embodiment, the tube is transversally and / or longitudinally stretched on the plastic phase, so that the obtained multilayer composite film is stretched. This stretch process often results in a stronger, mechanically improved film. The film tube is cooled down (e.g. by air), often laid flat with the help of rolls. After this step, the flat double layer film often is slit at both sides, resulting in a separated double layer film, which subsequently can be isolated in two separate single layers of the multilayer composite film. Just for the avoidance of doubt, these single layer films are still composed of multiple polymer segment layers (e.g. segments (a), (b) and optionally (c), as outlined before).

[0199] Applications

[0200] The vinylaromatic polymer composite article according to the invention is preferably used as component of a refrigerating device or a freezing device, in particular as a component of a refrigerator or a freezer. In one aspect, the invention relates to the use of a vinylaromatic polymer composite article according to the invention as component of refrigerating devices or freezing devices, in particular refrigerators or freezers. Further application examples include automotive interior parts, such as consoles, dashboard carriers, knobs, decorative parts, covers; electric / electronical applications, such as housing for tools, kitchen appliance housing, housing and / or parts for vacuum cleaners, coffee machine parts, edge bands, decorative covers; toys; healthcare applications and / or parts of healthcare applications, such as housings, carriers for diagnostics / analytics: single layer and / or multilayer laminates or coextruded films or sheets; and other industrial applications requiring a combination of impact resistance and stiffness.

[0201] Examples of vinylaromatic polymer composite article according to the invention include (but are not restricted to) multilayer articles such as ABS liner with two ABS layers of different composition (as segments (a) and (b)); ABS liner with an ABS main layer (as segment (a)) and a foamed back layer (as segment (b)), e.g. for thermal insulation; ABS liner with an ABS main layer (as segment (a)) and at least one SAN-containing layer (as segment (b)), e.g. as “gloss cap layer”; polystyrene liner with two polystyrene layers of different composition (as segments (a) and (b)); Polystyrene liner with a polystyrene main layer (as segment (a)) and a foamed back layer (as segment (b)), e.g. for thermal insulation. In a preferred embodiment the vinylaromatic polymer composite article comprises a main layer (segment (a)) made of “high impact polystyrene” (HIPS)), and a foamed back layer (segment (b)) made of polystyrene (e.g. either “high impact polystyrene” (HIPS) and / or “general purpose polystyrene” (GPPS)). Optionally, this vinylaromatic polymer composite article contains at least one additional layer (segment (c)), e.g. a layer with superior aesthetic properties such as surface gloss (“gloss cap layer”) containing polystyrene, preferably “general purpose polystyrene” (GPPS).

[0202] A further example of vinylaromatic polymer composite article according to the invention includes multilayer articles such as polystyrene liner with polystyrene main layer (as segment (a)) and at least one polystyrene-containing layer (as segment (b)), e.g. as “gloss cap layer”. In a preferred embodiment, both layers are made of “high impact polystyrene” (HIPS). In an even more preferred embodiment, the main layer is made of “high impact polystyrene” (HIPS) and the gloss cap layer contains “general purpose polystyrene” (GPPS).

[0203] Further examples of vinylaromatic polymer composite article according to the invention include food packaging films made of different polymers, for example different styrenic polymers; laminated structures containing different polymers, for example different styrenic polymers; and co-injection molded and / or over-molded structures containing different polymers, for example different styrenic polymers.

[0204] Further application examples include refrigerators, which are predominantly made of styrene polymers and styrene copolymers (also referred to all-styrenics fridges in the following), which are for example (i) based mainly on (i) SAN and / or ABS or (ii) based mainly on general purpose polystyrene (GPPS) and / or high impact polystyrene (HIPS) and / or styrene / butadiene (block) copolymers. Examples of suitable fridge components ready for recycling are (for example, further components possible):

[0205] (1.1) refrigerator liner: ABS, optionally with 1 or more cap layers or co-extrusion layers made of ABS, and / or of SAN and / or of polystyrene, compatibilized with suitable compatibilizer, for example styrene / butadiene copolymers;

[0206] (1.2) transparent and non-transparent shelves made of SAN or SAN blends; (i.3) butter / egg compartments made of ABS, and / or of SAN;

[0207] (1.5) vegetable / cheese / meat compartments made of SAN or SAN blends, in one specific embodiment comprising styrene / butadiene copolymers as impact-modifier;

[0208] (1.6) thermal insulation parts made of ABS and / or SAN, extruded or as bead foam;

[0209] (11.1) refrigerator liner: HIPS or HIPS / GPPS, optionally with 1 or more cap layers or co-extru- sion layers made of GPPS, and / or GPPS / HIPS and / or GPPS / SBC and / or of polystyrene, optionally compatibilized with suitable compatibilizer;

[0210] (11.2) transparent and non-transparent shelves made of GPPS or GPPS / SBC blends;

[0211] (11.3) butter / egg compartments made of HIPS, and / or of HIPS / GPPS;

[0212] (11.4) vegetable / cheese / meat compartments made of GPPS or GPPS blends, in one specific embodiment comprising styrene / butadiene copolymers as impact-modifier;

[0213] (11.5) thermal insulation parts made of HIPS and / or GPPS, extruded or as bead foam.

[0214] A further application example includes automotive interior parts, such as consoles, dashboard carriers, knobs, decorative parts, covers, all of the afore-mentioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled ABS, optionally including polymers selected from the group consisting of polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylonitrile) (SAN), styrene-butadiene copolymer (SBC), high impact polystyrene (HIPS), N-phenylmaleimide copolymers, thermoplastic polyurethanes, and virgin ABS and / or SAN (non-recycled).

[0215] A further application example includes parts for electric / electronical applications, such as housing for tools, kitchen appliance housing, housing and / or parts for vacuum cleaners, coffee machine parts, edge bands, decorative covers, all of the afore-mentioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled ABS, optionally including polymers selected from the group consisting of polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylonitrile) (SAN), styrene-methyl methacrylate copolymers, styrene-butadiene copolymer (SBC), high impact polystyrene (HIPS), N- phenylmaleimide copolymers, thermoplastic polyurethanes, and virgin ABS (non-recycled).

[0216] A further application example includes toys and / or parts of toys, all of the afore-mentioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled ABS, optionally including polymers selected from the group consisting of polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylonitrile) (SAN), styrene-butadiene copolymer (SBC), high impact polystyrene (HIPS), N-phenylmaleimide copolymers, thermoplastic polyurethanes, virgin ABS and / or SAN (non-recycled).

[0217] A further application example includes healthcare applications and / or parts of healthcare applications, such as housings, carriers for diagnostics / analytics, infusion sets, all of the aforementioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled ABS, optionally including polymers selected from the group consisting of polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylo- nitrile) (SAN), styrene-butadiene copolymer (SBC), high impact polystyrene (HIPS), N-phe- nylmaleimide copolymers, and virgin ABS and / or SAN (non-recycled).

[0218] A further application example includes healthcare applications and / or parts of healthcare applications, such as housings, carriers for diagnostics / analytics, infusion sets, all of the aforementioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled HIPS and / or GPPS, optionally including polymers selected from the group consisting of styrene-butadiene copolymer (SBC), styrene-methyl methacrylate copolymers, and virgin HIPS and / or GPPS (non-recycled).

[0219] A further application example includes single layer and / or multilayer laminates or coextruded films and / or sheets, containing recycled layers, all of the afore-mentioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled ABS, optionally including polymers selected from the group consisting of polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylonitrile) (SAN), styrene-butadiene copolymer (SBC), high impact polystyrene (HIPS), N-phenylmaleimide copolymers, thermoplastic polyurethanes, and virgin ABS and / or SAN (non-recycled).

[0220] A further application example includes single layer and / or multilayer laminates or coextruded films and / or sheets (for example used in food packaging), containing recycled layers, all of the afore-mentioned applications comprising (or consisting of) foamed and / or non-foamed moldings made fully or partly of recycled polystyrene (e.g. HIPS and / or GPPS), optionally including polymers selected from the group consisting of styrene-butadiene copolymer (SBC), styrenemethyl methacrylate copolymers, and virgin HIPS and / or GPPS (non-recycled).

[0221] The invention also relates to a component of a refrigerating device or a freezing device, in particular for a refrigerator or a freezer, automotive interior parts, electric / electronical applications, toys, healthcare applications and / or parts of healthcare applications, single layer and / or multilayer laminates or coextruded films and / or sheets, and other industrial applications requiring a combination of impact resistance and stiffness, using or comprising the vinylaromatic polymer composite article according to the invention.

[0222] The invention further relates to a vinylaromatic polymer composite article according to the invention as and when used as a component of a refrigerating device or a freezing device, in particular as a component of a refrigerator or a freezer, automotive interior parts, electric / electronical applications, toys, healthcare applications and / or parts of healthcare applications, single layer and / or multilayer laminates or coextruded films and / or sheets, and other industrial applications requiring a combination of impact resistance and stiffness.

[0223] The invention is described in more detail by the following examples and claims. Examples

[0224] Materials:

[0225] The following materials were used in the example compositions:

[0226] GPPS: General purpose polystyrene.

[0227] HIPS: High impact polystyrene consisting of 90 wt.-% polymerized styrene, 8 wt.-% polymerized butadiene and 2 wt.-% additives (oil, stabilizer, filler).

[0228] SBC: Styrene-butadiene-copolymer consisting of 70 wt.-% polymerized styrene, 26 wt-

[0229] % polymerized butadiene, and 4 wt.-% additives (oil, stabilizer, filler).

[0230] SAN-1 : Acrylonitrile-styrene copolymer comprising 67 wt.-% styrene and 33 wt.-% acrylonitrile and having a viscosity number VN of 60 determined according to DIN 53726.

[0231] SAN-2: Acrylonitrile-styrene copolymer comprising 75 wt.-% styrene and 25 wt.-% acrylonitrile and having a viscosity number VN of 60 determined according to DIN 53726.

[0232] SAN-3: Acrylonitrile-styrene copolymer comprising 81 wt.-% styrene and 19 wt.-% acrylonitrile and having a viscosity number VN of 60 determined according to DIN 53726.

[0233] ABS: Graft copolymer (rubbery polymer) consisting of 60 wt.-% graft base made of polybutadiene and 40 wt.-% graft shell made of 75 wt.-% styrene and 25 wt-% acrylonitrile, prepared by emulsion polymerization, having a mean particle diameter D5o of 350 nm.

[0234] Additives: additive package comprising oil, stabilizers, and fillers

[0235] Methods

[0236] The following methods were used for characterizing the materials and the example compositions:

[0237] Viscosity numbers (VN) are generally determined according to DIN 53726 at 25°C, using a solution of 0.5% by weight polymer in dimethylformamide (DMF).

[0238] The mean particle diameter D50 are determined by ultracentrifuge measurements (see W. Scholtan, H. Lange: Kolloid Z. & Z. Polymere 250, p. 782 to 796 (1972)).

[0239] Preparation of two-layer composite articles

[0240] Two-layer composite articles are obtained by co-extrusion of the vinylaromatic copolymer compositions A and B. Different vinylaromatic copolymer compositions A and B as described in Table 2 were melt blended at T = 250 °C on a Coperion ZSK 30 extruder. The obtained liquid melts were fed together in a co-extrusion die, resulting in co-extrusion layers, which are subsequently cooled. Test specimens were prepared and subjected to delamination tests according to ISO 527-1:2019. The delamination properties were rated by a panel of experts according to the following rating:

[0241] Table 1. Delamination property rating

[0242] Table 2: Examples

[0243]

[0244] Within the meaning of the invention, the term “difference in in content of A-11 and B-11 in A-1 and B-1“ refers to the difference in percentages of repeating units A-11 in component A-1 compared to the percentages of repeating units B-11 in component B-1. E.g., in Example 3 the component A-1 contains 67 wt.-% styrene, and the component B-1 contains 81 wt.-% styrene, so the difference in styrene content is 14 wt.-%.

[0245] As can be seen from the test results, the vinylaromatic polymer composite articles according to the invention (Ex. 1 to 4), wherein the percentages of repeating units A-11 , based on the total weight of the vinylaromatic polymers A-1 , repeating units B-11, based on the total weight of the vinylaromatic polymers B-1 , and optionally repeating units C- 11 , based on the total weight of the vinylaromatic polymers C-1 , differ from each other by < 25 wt.-% (i.e. 0 wt.-%, 14 wt.-% and 19 wt.-%, respectively) exhibit superior delamination stability compared to the comparative examples Comp. Ex. 1 to Comp. Ex. 4, wherein the percentages of repeating units A-11, based on the total weight of the vinylar- omatic polymers A-1 , repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 , and optionally repeating units C-11, based on the total weight of the vinylaromatic polymers C-1, differ from each other by > 25 wt.-% (i.e. 25 and 33 wt.-%, respectively).

Claims

Claims1. Vinylaromatic polymer composite article comprising or consisting of:(a) at least one segment (a) comprising or consisting of at least one first vinylaromatic polymer composition A, comprising:A-1 : 50 to 98 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one vinylaromatic copolymer A-1 , comprising or consisting of:A-11 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic copolymer A-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; andA-12: 0 to 50 wt.-%, based on the total weight of the vinylaromatic copolymer A-1 , of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) A-11 ;A-2: 2 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one rubbery polymer A-2, dispersed in the vinylaromatic copolymer A-1 ;A-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one further polymer; andA-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition A, of at least one additive, wherein the sum of components A-1 , A-2, A-3 and A-4 is 100 wt.-%;(b) at least one segment (b) comprising or consisting of at least one second vinylaromatic polymer composition B, comprising:B-1: 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one vinylaromatic polymer B-1 , comprising or consisting of:B-11 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic copolymer B-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; andB-12: 0 to 50 wt.-%, based on the total weight of the vinylaromatic copolymer B-1 , of repeating units of at least one comonomer, which is copolymerizable with the monomers) B-11 ;B-2: 0 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one rubbery polymer B-2, dispersed in the vinylaromatic polymer B-1 ;B-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one further polymer; andB-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition B, of at least one additive, wherein the sum of components B-1 , B-2, B-3 and B-4 is 100 wt.-%;(c) optionally at least one segment (c) comprising or consisting of at least one further vinylaromatic polymer composition C, comprising parts comprising C-1 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one vinylaromatic polymer C-1 , comprising or consisting of:C-11 : 50 to 100 wt.-%, based on the total weight of the vinylaromatic copolymer C-1 , of repeating units selected from the group of monomers consisting of styrene, alpha-methylstyrene, para-methylstyrene, and mixtures of at least two of the afore-mentioned; andC-12: 0 to 50 wt.-%, based on the total weight of the vinylaromatic copolymer C-1, of repeating units of at least one comonomer, which is copolymerizable with the monomer(s) C-11 ;C-2: 0 to 50 wt.-%, based on the total weight of the vinylaromatic polymer composition C, at least one rubbery polymer C-2, dispersed in the vinylaromatic polymer C-1;C-3: 0 to 48 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one further polymer C-3; andC-4: 0 to 20 wt.-%, based on the total weight of the vinylaromatic polymer composition C, of at least one additive C-4, wherein the sum of components C-1 , C-2, C-3 and C-4 is 100 wt.-%; wherein the vinylaromatic polymer composite article is characterized in that the percentages of repeating units A-11, based on the total weight of the vinylaromatic polymers A-1 , repeating units B-11 , based on the total weight of the vinylaromatic polymers B-1 , and optionally repeating units C-11, based on the total weight of the vinylaromatic polymers C-1, differ from each other by < 25 wt.-%, preferably by < 20 wt.-%, often < 15 wt.-%, for example < 10 wt.-%.

2. Vinylaromatic polymer composite article according to claim 1 , wherein the rubbery polymer A-2 comprises or consists of:A-21 : rubber obtained by a emulsion polymerization reaction; and / or A-22: rubber obtained by a solution polymerization reaction, and / or A-23: rubber obtained by a mass polymerization reaction; and / or A-24: rubber obtained by an anionic and / or living polymerization reaction, preferably comprising (or consisting of) butadiene, isoprene, and / or acrylate.

3. Vinylaromatic polymer composite article according to claim 1 or 2, wherein the rubbery polymer B-2 comprises or consists of:B-21 : rubber obtained by a emulsion polymerization reaction; and / or B-22: rubber obtained by a solution polymerization reaction, and / or B-23: rubber obtained by a mass polymerization reaction; and / or B-24: rubber obtained by an anionic and / or living polymerization reaction, preferably comprising (or consisting of) butadiene, isoprene, and / or acrylate.

4. Vinylaromatic polymer composite article according to any of claims 1 to 3, wherein the vinylaromatic polymer composite article comprises:(a) 20 to 80 wt-% of the at least one segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;(b) 20 to 80 wt-% of the at least one segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and(c) 0 to 60 wt.-% of the at least one segment (c) of the at least one further vinylaromatic polymer composition C, wherein the sum of segments (a), (b) and (c) is 100 wt.-%.

5. Vinylaromatic polymer composite article according to claim 4, wherein at least one of the segments (a), (b) and / or (c) is configured as a polymer foam, preferably the at least one segment (b).

6. Vinylaromatic polymer composite article according to claim 4 or 5, wherein the vinylaromatic polymer composite article is a layered vinylaromatic polymer composite article comprising:(a) at least one layered segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;(b) at least one layered segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and(c) optionally at least one layered segment (c) comprising or consisting of the at least one further vinylaromatic polymer composition C.

7. Vinylaromatic polymer composite article according to claim 6 comprising:(a) at least one thermoformed layered segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;(b) at least one foamed layered segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B; and(c) optionally at least one further layered segment (c) comprising or consisting of the at least one further vinylaromatic polymer composition C.

8. Vinylaromatic polymer composite article according to claim 7, wherein the at least one thermoformed layered segment (a) is a thermoformed refrigerator liner and the at least one foamed layered segment (b) is a refrigerator insulation foam.

9. Vinylaromatic polymer composite article according to claim 8, wherein the thermoformed layered segment (a) is a thermoformed refrigerator liner having a thickness of < 10 mm.

10. Vinylaromatic polymer composite article according to any of the claims 1 to 9, wherein the first vinylaromatic polymer composition A consists of the constituents A-1 , A-2 and optionally A-4.

11. Vinylaromatic polymer composite article according to any of the claims 1 to 10, wherein the second vinylaromatic polymer composition B consists of the constituents B-1 , B-2 and optionally B-4.

12. Vinylaromatic polymer composite article according to any of the claims 1 to 11 , wherein melt blending of constituents A-1 and A-2 with constituents B-1 and B-2 and optionally with constituents C-1 and C-2 at temperatures below 250 °C in a mixing device results in a micro-dispersed morphology with either a single phase morphology or a two-phase morphology having an average domain size of less than 20 pm.

13. Vinylaromatic polymer composite article according to any of the claims 1 to 12, wherein the additives A-4, B-4 and C-4 are each independently selected from the group of additives consisting of foaming agents, stabilizers, processing aids, mineral fillers, glass fibers, carbon fibers, and mixtures of at least two of the aforementioned.

14. Process for producing a vinylaromatic polymer composite article according to any of the claims 1 to 13 as component of a refrigerating device or freezing device, comprising the process steps:(i) providing at least one thermoformed layered segment (a) comprising or consisting of the at least one first vinylaromatic polymer composition A;(ii) providing at least one layered segment (b) comprising or consisting of the at least one second vinylaromatic polymer composition B on at least a part of at least one surface of the thermoformed layered segment (a) provided in process step (i) to obtain a first laminate structure (I); and(iii) optionally providing at least one further layered segment (c) comprising or consisting of the at least one further vinylaromatic polymer composition C on at least a part of at least one surface of the first laminate structure (I) obtained in process step (ii) to obtain a second laminate structure (II).

15. Use of a vinylaromatic polymer composite article according to any of the claims 1 to 13 as component of refrigerating devices or freezing devices, automotive interior parts, electric / electronical applications, toys, healthcare applications and / or parts of healthcare applications, single layer and / or multilayer laminates or coextruded films and / or sheets, and other industrial applications requiring a combination of impact resistance and stiffness.

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