EP4237474A1 - Expandable, thermoplastic polymer particles based on styrene polymers and process for the preparation thereof - Google Patents

Expandable, thermoplastic polymer particles based on styrene polymers and process for the preparation thereof

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Publication number
EP4237474A1
EP4237474A1 EP21801543.6A EP21801543A EP4237474A1 EP 4237474 A1 EP4237474 A1 EP 4237474A1 EP 21801543 A EP21801543 A EP 21801543A EP 4237474 A1 EP4237474 A1 EP 4237474A1
Authority
EP
European Patent Office
Prior art keywords
polymer particles
expandable
styrene
thermoplastic polymer
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21801543.6A
Other languages
German (de)
French (fr)
Inventor
Bianca WILHELMUS
Yvonne VAN VEEN
Dominik DÖRR
Sebastian GRÖSCHEL
Tobias STANDAU
Volker ALTSTÄDT
Regino WEBER
Thomas Neumeyer
Peter Schreier
Max LÖHNER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ineos Styrolution Group GmbH
Original Assignee
Ineos Styrolution Group GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ineos Styrolution Group GmbH filed Critical Ineos Styrolution Group GmbH
Publication of EP4237474A1 publication Critical patent/EP4237474A1/en
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/228—Forming foamed products
    • C08J9/232—Forming foamed products by sintering expandable particles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0066—Use of inorganic compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
    • C08J9/141—Hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/16—Making expandable particles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/02—Foams characterised by the foaming process characterised by mechanical pre- or post-treatments
    • C08J2201/03—Extrusion of the foamable blend
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/02—Foams characterised by the foaming process characterised by mechanical pre- or post-treatments
    • C08J2201/034—Post-expanding of foam beads or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/14—Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/08—Copolymers of styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/08—Copolymers of styrene
    • C08J2325/12—Copolymers of styrene with unsaturated nitriles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2355/00—Characterised by the use of homopolymers or copolymers, obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in groups C08J2323/00 - C08J2353/00
    • C08J2355/02—Acrylonitrile-Butadiene-Styrene [ABS] polymers

Definitions

  • the invention relates to expandable polymer particles based on styrene polymers, a process for their production and the use of the expandable polymer particles for foam moldings.
  • Particle foams have been used in numerous applications for years, including building insulation, packaging, and automotive structural lightweight wall materials.
  • Particle foams usually consist of many foamed (expanded) polymer beads that are welded together. Compared to solid materials, particle foams typically offer the advantage of weight reduction with good mechanical properties at the same time.
  • Particle foams made from polyolefins such as polyethylene
  • polyolefins such as polyethylene
  • CN-A 107501595 describes a process for producing particles made from expanded polypropylene.
  • a disadvantage of particle foams made from polyolefins is that they have to be completely foamed during production, since the blowing agent does not remain in the polymer material for a long time. It is not possible to produce polyolefin particles loaded with blowing agent which can still be expanded after a certain storage time. Therefore, a temporal and spatial separation of production of the particles and processing (foaming) is not possible, which is desirable in practice. Only polyolefin particles that have already been foamed can be manufactured and processed. Due to the high total volume, the transport of such particles is more complex than the transport of non-foamed products or particles.
  • EP-A 2384355 (BASF) describes expandable, thermoplastic polymer particles containing a styrene polymer and a polyolefin. Since the polymers used are not miscible with one another, a compatibilizer must be used to adjust the morphology.
  • the use of polyolefins and compatibilizers is necessary to achieve particle foams with high rigidity and good elasticity, which cannot be achieved with a particle foam consisting only of polystyrene.
  • the use of polyolefins with a compatibilizer requires at least one additional process step, the production of a blend of at least three components, polystyrene, polyolefin and compatibilizer.
  • suitable compatibilizers are often complex and the production of these components is expensive.
  • a material consisting of only one type of polymer is advantageous, which can be reintroduced into the corresponding material cycle.
  • US Pat. No. 4,108,806 (Dow, 1978) describes a process for producing expanded and expandable polymer particles based on a polyolefin matrix, into which expandable microspheres are introduced.
  • the microspheres consist of a thermoplastic shell and a core of a volatile liquid blowing agent, which causes the polymer mass to expand when heated. This production method is complex and a polymer mixture of two or more types of polymers is produced.
  • WO 2013/085742 (Dow) describes the provision of an extruded polymer foam using a blowing agent mixture of 74-78% by weight of 1,1,1,2-tetrafluoroethane, 13-16% by weight of CO2 and 7- 9 wt .-% water is produced, but it is not based on the provision of expandable polymer particles.
  • US7919538 (Dow) describes a particle foam consisting of SAN and an additive that shields infrared radiation for the purpose of improved thermal insulation; expandable polymer particles are not sought.
  • US3945956 describes a process for producing expandable polymer particles in which a volatile liquid blowing agent is enclosed in a hollow sphere made of styrene and acrylonitrile.
  • the blowing agent is encapsulated in a polymer particle but not homogeneously distributed in a polymer matrix. When such polymer particles expand, this results in a foam with inhomogeneously distributed cavities.
  • US5480599 describes a process for producing particle foams.
  • the propellant can be at least partially recovered after expansion of the particles.
  • the process only provides expanded polymer particles, not expandable particles.
  • US5049328 describes a process for producing foam without organic blowing agents. Only inert gases such as CO2, nitrogen or air are used as propellants. The process is not suitable for providing expandable polymer particles that can be stored for a certain period of time (eg days, weeks, months). the gases consisting of small molecules can escape quickly from the polymer mass if necessary.
  • An object of the present invention is therefore to provide expandable, thermoplastic polymer particles with low loss of blowing agent and high expansion capacity, which (even after processing) can be recycled without great technical effort and which can be processed into particle foams with high rigidity and good elasticity, and a Process for their manufacture.
  • the expandable, thermoplastic polymer particles contain or preferably consist of:
  • B) 1 to 10% by weight, preferably 3 to 7% by weight, based on the total weight of (A), (B) and (C), of one or more blowing agents (B);
  • C 0 to 3% by weight, preferably 0.1 to 2% by weight, based on the total weight of (A), (B) and (C), of one or more nucleating agents or nucleating agents (C); and optionally one or more further additives (Z) in an amount which does not impair the formation of domains and the resulting foam structure.
  • the expandable, thermoplastic polymer particles generally contain no further polymers apart from the one or more styrene polymers (A); where the styrene polymers (A) are miscible with one another if the expandable, thermoplastic polymer particles contain a plurality of styrene polymers (A); and wherein the expandable, thermoplastic polymer particles are thermoplastically recyclable.
  • thermoplastically recyclable means that the expandable, thermoplastic polymer particles are well suited (without high technical complexity) for recycling, for example in a mechanical recycling process.
  • Styrene polymers are particularly suitable for recycling if the styrene polymer (A) consists of only one polymer class, or if the several styrene polymers (A) consist of polymer classes that are readily miscible with one another, such as SAN, AMSAN, ABS and ASA.
  • the styrenic polymer (A) consists of only one class of polymers such as SAN, AMSAN, ABS and ASA.
  • the expandable polymer particles according to the invention can be recycled particularly well, for example in mechanical recycling processes.
  • the styrene polymer (A) consists of polymer classes which are miscible with one another. Even then, there is a good ability or suitability for recycling, e.g. in mechanical recycling processes. Good miscibility is shown, for example, by the fact that two or more phases are not formed at the processing temperature (e.g. 200-260 °C).
  • the blowing agent (B) is preferably distributed homogeneously in the expandable, thermoplastic polymer particles in a polymer matrix composed of one or more of the styrene polymers (A).
  • the expandable thermoplastic polymer particles contain 87 to 99% by weight, preferably 91 to 97% by weight, particularly preferably 93.5 to 97% by weight, based on the total weight of (A), (B) and (C) , one or more styrene polymers (A), which are selected, for example, from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene copolymers (ABS), acrylate-styrene-acrylonitrile copolymers (ASA) , methyl methacrylate-acrylonitrile-butadiene-styrene copolymers (MABS), methyl methacrylate-butadiene-styrene copolymers (MBS), a(alpha)-methylstyrene-acrylonitrile copolymers (AMSAN), styrene-methyl methacrylate copolymers (SMMA), amorphous
  • the styrene polymer (A) is preferably selected from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene copolymers (ABS) or acrylonitrile-styrene-acrylate copolymers (ASA).
  • SAN styrene-acrylonitrile copolymers
  • ABS acrylonitrile-butadiene-styrene copolymers
  • ASA acrylonitrile-styrene-acrylate copolymers
  • Styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers or acrylonitrile-styrene-acrylate copolymers with a melt volume rate MVR (220° C./10 kg) according to ISO 1133 in the range from 1 to 12 cm 3 /10 min are particularly preferred , preferably in the range from 1 to 10 cm 3 /10 min.
  • the styrene polymer (A) contains no styrene homopolymer.
  • the expandable, thermoplastic polymer particles contain no other polymers than the styrene polymer (A), which preferably contains no styrene homopolymer.
  • Component (A) consists, for example, of SAN, ABS, ASA and/or mixtures containing at least two of these polymers. In the case of ABS as component (A), at least one component (C) is preferably also used.
  • the expandable, thermoplastic polymer particles contain 1 to 10% by weight, preferably 3 to 7% by weight, particularly preferably 4 to 6% by weight, based on the total weight of (A), (B) and (C), one or more physical blowing agents, such as CO2, aliphatic Cs to Cs hydrocarbons, alcohols, ketones, ethers or halogenated hydrocarbons, preferably CO2 or alternatively isobutane, n-butane, isopentane , n-pentane (bp 36°C), cyclopentane, or mixtures thereof.
  • one or more physical blowing agents such as CO2, aliphatic Cs to Cs hydrocarbons, alcohols, ketones, ethers or halogenated hydrocarbons, preferably CO2 or alternatively isobutane, n-butane, isopentane , n-pentane (bp 36°C), cyclopentane, or mixtures thereof.
  • the expandable, thermoplastic polymer particles contain 0 to 3% by weight, preferably 0 to 2% by weight, often 0.1 to 2% by weight, particularly preferably 0.1 to 0.8% by weight. -%, based on the total weight of (A), (B) and (C), of one or more nucleating or nucleating agents, for example talc, alumina or silica.
  • additives (Z) such as plasticizers, flame retardants, soluble and insoluble inorganic and / or organic dyes and pigments, fillers, co-blowing agents or other additives can be added in amounts to the expandable, thermoplastic polymer particles, which the domain formation and from it do not impair the resulting foam structure (e.g. in the range from 0.1 to 5% by weight, in the range from 0.1 to 2% by weight, preferably from 0.1 to 0.9% by weight, based on the total composition).
  • additives (Z) such as plasticizers, flame retardants, soluble and insoluble inorganic and / or organic dyes and pigments, fillers, co-blowing agents or other additives can be added in amounts to the expandable, thermoplastic polymer particles, which the domain formation and from it do not impair the resulting foam structure (e.g. in the range from 0.1 to 5% by weight, in the range from 0.1 to 2% by weight, preferably from 0.1 to 0.9% by weight, based on the total composition).
  • Customary plastic additives and auxiliaries can be present as additives in the expandable, thermoplastic polymer particles.
  • an additive or an auxiliary can be selected from the group consisting of antioxidants, UV stabilizers, peroxide destroyers, antistatic agents, lubricants, mold release agents, flame retardants, fillers or reinforcing materials (glass fibers, carbon fibers, etc.), colorants and combinations of two or more of it.
  • oxidation retardants and heat stabilizers are halides of metals from group I of the periodic table, for example sodium, potassium and/or lithium halides, optionally in combination with copper(I) halides, for example chlorides, bromides, Iodides, sterically hindered phenols, hydroquinones, substituted representatives of these groups and mixtures thereof in concentrations of up to 1% by weight, based on the total weight of the expandable, thermoplastic polymer particles.
  • organic dyes such as nigrosine, pigments such as titanium dioxide, phthalocyanines, ultramarine blue and carbon black can be contained as dyes in the thermoplastic polymer particles, as well as fibrous and pulverulent fillers and reinforcing agents.
  • examples of the latter are carbon fibers, glass fibers, amorphous silica, calcium silicate (wollastonite), aluminum silicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica and feldspar.
  • Long-chain fatty acids are examples of lubricants and mold release agents, which can generally be used in amounts of up to 1% by weight, often 0.1-0.8% by weight, based on the total weight of the expandable, thermoplastic polymer particles such as stearic acid or behenic acid, their salts (e.g. Ca or Zn stearate) or esters (e.g. stearyl stearate or pentaerythritol tetrastearate) and amide derivatives (e.g. ethylenebisstearylamide).
  • their salts e.g. Ca or Zn stearate
  • esters e.g. stearyl stearate or pentaerythritol tetrastearate
  • amide derivatives e.g. ethylenebisstearylamide
  • Mineral-based antiblocking agents can also be present in amounts of up to 0.1% by weight, based on the total weight of the expandable, thermoplastic polymer particles. Examples which may be mentioned are amorphous or crystalline silica, calcium carbonate or aluminum silicate.
  • Mineral oil preferably medicinal white oil
  • plasticizers which may be mentioned are dioctyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, hydrocarbon oils, N-(n-butyl)benzenesulfonamide and o- and p-tolylethylsulfonamide.
  • non-halogen-containing flame retardants known for the respective thermoplastics can be present, in particular those based on phosphorus compounds.
  • the expandable, thermoplastic polymer particles consist of the styrene polymer (A) and the blowing agent (B). In a further embodiment, the expandable, thermoplastic polymer particles consist of the styrene polymer (A), the blowing agent (B) and the nucleating agent or nucleating agent (C). In a further embodiment, the expandable, thermoplastic polymer particles consist of the styrene polymer (A), the blowing agent (B), the nucleating agent or nucleating agent (C) and other additives (Z) in amounts which do not impair domain formation and the resulting foam structure.
  • styrene polymer (A) is an acrylonitrile-butadiene-styrene copolymer (ABS)
  • ABS acrylonitrile-butadiene-styrene copolymer
  • C nucleating agent
  • One subject of the invention is a process for producing expandable, thermoplastic polymer particles, comprising the steps of: a) mixing a styrene polymer (A) with a blowing agent (B) and optionally a nucleating agent or nucleating agent (C), and optionally additives in amounts that Do not affect domain formation and resulting foam structure, so that a polymer mixture (I) is formed. b) pre-expanding the polymer mixture (I).
  • only the styrenic polymer (A) and the blowing agent (B) are used as starting materials in the process.
  • only the styrenic polymer (A), the blowing agent (B) and the nucleating agent or nucleating agent (C) are used in the process.
  • only the styrene polymer (A), the blowing agent (B), the nucleating agent or the nucleating agent (C) and other additives (Z) are used in the process in amounts which do not impair domain formation and the resulting foam structure.
  • At least step b), particularly preferably steps a) and b), preferably takes place under a pressure which exceeds atmospheric pressure.
  • process steps a) and b) take place in an extruder with subsequent underwater granulation at a pressure in the range from 1.5 to 11 bar.
  • process steps a) and b) take place in an autoclave.
  • the granulated styrene polymer (A) to which a nucleating agent (C) and optionally further additives have optionally been added, is impregnated under pressure with the blowing agent (B) to form expandable, thermoplastic polymer particles. These can then be isolated or obtained as prefoamed foam particles directly by decompression.
  • the styrene polymer (A) is synthesized in a suspension and treated with a physical blowing agent.
  • a continuous process is particularly preferred in which, in process step a), a thermoplastic styrene polymer (A), for example SAN, ABS or ASA, optionally mixed with the nucleating agent (C) and optionally the other additives, is melted in a twin-screw extruder and mixed with the blowing agent ( B) is impregnated.
  • the melt loaded with blowing agent can then be extruded and cut in process step b) through an appropriate nozzle to form foam sheets, strands or particles.
  • a preferred embodiment is extrusion through a microperforated plate with one or, as a rule, several holes with a hole diameter of 0.1 to 2.4 mm, preferably 0.2 to 1.2 mm, particularly preferably from 0.5 to 0.8 mm, so that particles are formed.
  • the melt emerging from the microperforated plate is fed into a stream of water, where the melt is cut up into individual particles by a suitable device.
  • the setting of the appropriate back pressure and a suitable temperature in the water flow of this so-called underwater granulation enables a targeted production of expandable polymer particles.
  • the expandable, thermoplastic polymer particles according to the invention preferably have an average particle diameter in the range from 0.1 to 3 mm, preferably from 0.3 to 2 mm, particularly preferably from 0.5 to 1 mm. Expandable polymer particles with a narrow particle size distribution and an average particle diameter in the range mentioned lead to better filling of the mold when the polymer particles are welded to form a molded part. They enable a more filigree part design and a better part surface. In a further preferred embodiment, the expandable, thermoplastic polymer particles are prefoamed. The expandable polymer particles obtained are preferably foamed to an average diameter in the range from 0.2 to 10 mm.
  • the specific density of the expanded polymer particles is preferably in the range from 10 to 250 g/l, particularly preferably 20 to 200 g/l, particularly preferably 25 to 150 g/l and particularly preferably 30-100 g/l.
  • the expandable, thermoplastic polymer particles according to the invention can be filled into a mold which is then closed and hot air or steam flows through it and is thus heated.
  • the polymer particles expand further, ideally until the cavity is completely filled, and thus form foam moldings.
  • the processing pressure is chosen so low that the domain structure in the cell membranes is preserved.
  • the pressure is usually in the range from 0.5 to 1.0 bar.
  • a further object of the invention is accordingly the use of expandable, thermoplastic polymer particles as described above in a foam molding formed by welding the expandable polymer particles by means of hot air or steam.
  • the molding preferably has a specific density of less than 250 g/l, preferably less than 150 g/l.
  • the invention also relates to the foams or moldings obtained from the expandable, thermoplastic polymer particles.
  • the polymers (A) were mixed with the blowing agent (B) and optionally the nucleating agent (C) at 200-240 °C melted and mixed homogeneously.
  • the polymer mixture (I) obtained in this way was then cooled in a single-screw extruder (type E 45 M, manufacturer Collin GmbH) with a screw diameter of 45 mm and a length-to-diameter ratio of 30, and the melt was extruded through a heated perforated plate.
  • the polymer strand was cut off by means of underwater pelletizing, so that a propellant-loaded minigranulate with a narrow particle size distribution was obtained.
  • the minigranules loaded with blowing agent were then prefoamed in an X-Line 3 prefoamer (manufacturer Kurtz GmbH).
  • the pre-foamed polymer particles were welded in a TVZ 162/100 PP molding machine (manufacturer Teubert Maschinenbau GmbH) at approx. 120-125 °C in order to produce test specimens for measuring the thermal and mechanical properties.
  • the density of the prefoamed particles was determined in accordance with ISO 1183 using an AG245 density balance (manufacturer: Mettler Toledo).
  • the thermal characterization of the test specimens was carried out according to DIN EN 12667 with a heat flow measuring plate apparatus type HMF Lambda Small (manufacturer Netzsch) using test specimens with the dimensions 200 x 200 x 20 mm and a temperature gradient of 20 K.
  • test specimens The mechanical characterization of the test specimens was carried out using a 3-point bending test with a universal testing machine 1485 (manufacturer Zwick Roell) in accordance with ISO 1209 on test specimens measuring 120 x 25 x 20 mm, with a pressure of 0.5 N and a test speed of 10 mm /min
  • test specimens from the compositions according to the invention have better mechanical properties than the test specimens from the composition not according to the invention (comparative test 4).
  • compositions according to the invention can be stored well and lead to a better flexural modulus in test specimens than the bodies made from the composition not according to the invention (comparison 4).
  • blowing agents such as isobutane, n-butane, isopentane and cyclopentane instead of n-pentane.
  • the polymer products obtained or the moldings made of SAN or ABS can be recycled without great effort, e.g. with the recovery of styrene, which also makes them interesting for ecological reasons.

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  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
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Abstract

The invention relates to expandable polymer particles based on styrene polymers, to a process for the preparation thereof and to the use of the expandable polymer particles in a molded foam part. The polymer particles contain A) 87 to 99 wt.% of one or more styrene polymers (A), in relation to the total weight of (A), (B) and (C); B) 1 to 10 wt.% of one or more foaming agents (B); C) 0 to 3 wt.% of one or more nucleators or nucleating agents C); and optionally further additives (Z) in amounts which do not impair the domain formation and the foam structure resulting therefrom.

Description

Expandierbare, thermoplastische Polymerpartikel auf Basis von Styrolpolymeren und Verfahren zu deren Herstellung Expandable, thermoplastic polymer particles based on styrene polymers and process for their production
Beschreibung description
Die Erfindung betrifft expandierbare Polymerpartikel auf Basis von Styrolpolymeren, ein Verfahren zu ihrer Herstellung und die Verwendung der expandierbaren Polymerpartikel für Schaumstoff-Formteile. The invention relates to expandable polymer particles based on styrene polymers, a process for their production and the use of the expandable polymer particles for foam moldings.
Partikelschäume werden seit Jahren in zahlreichen Anwendungen verwendet, einschließlich der Isolation im Baubereich, Verpackungen und strukturellen, leichten Wandmaterialien im Automobilbereich. Dabei bestehen Partikelschäume meist aus vielen aufgeschäumten (expandierten) Polymer-Kügelchen, die miteinander verschweißt werden. Typischerweise bieten Partikelschäume gegenüber massiven Werkstoffen den Vorteil der Gewichtsreduktion bei gleichzeitig guten mechanischen Eigenschaften. Particle foams have been used in numerous applications for years, including building insulation, packaging, and automotive structural lightweight wall materials. Particle foams usually consist of many foamed (expanded) polymer beads that are welded together. Compared to solid materials, particle foams typically offer the advantage of weight reduction with good mechanical properties at the same time.
Partikelschäume aus Polyolefinen, wie Polyethylen, sind seit Jahrzehnten bekannt, siehe Patent US 6028121. In CN-A 107501595 wird ein Verfahren zur Herstellung von Partikeln aus expandiertem Polypropylen beschrieben. Ein Nachteil von Partikelschäumen aus Polyolefinen ist, dass diese bereits bei der Herstellung vollständig aufgeschäumt werden müssen, da das Treibmittel nicht über eine längere Zeit im Polymermaterial verbleibt. Es ist nicht möglich, mit Treibmittel beladene Polyolefin-Partikel herzustellen, die noch nach einer gewissen Lagerungszeit expandiert werden können. Daher ist eine zeitliche und räumliche Trennung von Herstellung der Partikel und Verarbeitung (Aufschäumen) nicht möglich, was in der Praxis aber wünschenswert ist. Es können nur bereits aufgeschäumte Polyolefin-Partikel hergestellt und verarbeitet werden. Der Transport solcher Partikel ist durch das hohe Gesamtvolumen aufwändiger als der Transport nicht aufgeschäumter Produkte bzw. Partikel. Particle foams made from polyolefins, such as polyethylene, have been known for decades, see US Pat. No. 6,028,121. CN-A 107501595 describes a process for producing particles made from expanded polypropylene. A disadvantage of particle foams made from polyolefins is that they have to be completely foamed during production, since the blowing agent does not remain in the polymer material for a long time. It is not possible to produce polyolefin particles loaded with blowing agent which can still be expanded after a certain storage time. Therefore, a temporal and spatial separation of production of the particles and processing (foaming) is not possible, which is desirable in practice. Only polyolefin particles that have already been foamed can be manufactured and processed. Due to the high total volume, the transport of such particles is more complex than the transport of non-foamed products or particles.
Es ist daher wünschenswert, expandierbare Polymerpartikel bereitzustellen, die über einen längeren Zeitraum gelagert und gegebenenfalls mit geringem Aufwand transportiert werden können. It is therefore desirable to provide expandable polymer particles that can be stored over a longer period of time and, if appropriate, transported with little effort.
EP-A 2384355 (BASF) beschreibt expandierbare, thermoplastische Polymerpartikel enthaltend ein Styrolpolymer und ein Polyolefin. Da die eingesetzten Polymere nicht miteinander mischbar sind, muss zur Einstellung der Morphologie ein Verträglichkeitsvermittler eingesetzt werden. Die Verwendung von Polyolefinen und Verträglichkeitsvermittler ist notwendig, um Partikelschäume mit hoher Steifigkeit und guter Elastizität zu erreichen, die mit einem nur aus Polystyrol bestehenden Partikelschaum nicht erzielt werden können. Die Verwendung von Polyolefinen mit einem Verträglichkeitsvermittler bedingt allerdings mindestens einen zusätzlichen Prozessschritt, die Herstellung eines Blends aus mindestens drei Komponenten, Polystyrol, Polyolefin und Verträglichkeitsvermittler. Zudem sind geeignete Verträglichkeitsvermittler häufig komplex und die Herstellung dieser Komponenten teuer. Darüber hinaus ist im Sinne eines vereinfachten Recyclings der Partikelschäume am Ende ihrer Lebensdauer ein nur aus einem Polymer-Typ bestehender Werkstoff vorteilhaft, der wieder in den entsprechenden Stoffkreislauf eingeführt werden kann. EP-A 2384355 (BASF) describes expandable, thermoplastic polymer particles containing a styrene polymer and a polyolefin. Since the polymers used are not miscible with one another, a compatibilizer must be used to adjust the morphology. The use of polyolefins and compatibilizers is necessary to achieve particle foams with high rigidity and good elasticity, which cannot be achieved with a particle foam consisting only of polystyrene. However, the use of polyolefins with a compatibilizer requires at least one additional process step, the production of a blend of at least three components, polystyrene, polyolefin and compatibilizer. In addition, suitable compatibilizers are often complex and the production of these components is expensive. In addition, in terms of simplified recycling of the particle foams at the end of their service life, a material consisting of only one type of polymer is advantageous, which can be reintroduced into the corresponding material cycle.
US 4108806 (Dow, 1978) beschreibt ein Verfahren zur Herstellung expandierter und ex- pandier-barer Polymerpartikel auf Basis einer Polyolefin-Matrix, in die expandier-bare Mikrosphären eingebracht werden. Die Mikrosphären bestehen aus einer thermoplastischen Hülle und einem Kern aus einem flüchtigen flüssigen Treibmittel, welches beim Erhitzen eine Expansion der Polymermasse bewirkt. Diese Herstellmethode ist aufwändig und es entsteht ein Polymergemisch aus zwei oder mehr Polymertypen. US Pat. No. 4,108,806 (Dow, 1978) describes a process for producing expanded and expandable polymer particles based on a polyolefin matrix, into which expandable microspheres are introduced. The microspheres consist of a thermoplastic shell and a core of a volatile liquid blowing agent, which causes the polymer mass to expand when heated. This production method is complex and a polymer mixture of two or more types of polymers is produced.
WO 2013/085742 (Dow) beschreibt die Bereitstellung eines extrudierten Polymerschaums, der mit Hilfe eines Treibmittelgemisches aus 74-78 Gew.-% 1 , 1 , 1 ,2-Tetraflu- oroethan, 13-16 Gew.-% CO2 und 7-9 Gew.-% Wasser hergestellt wird, es wird jedoch nicht auf die Bereitstellung expandierbarer Polymerpartikel abgestellt. WO 2013/085742 (Dow) describes the provision of an extruded polymer foam using a blowing agent mixture of 74-78% by weight of 1,1,1,2-tetrafluoroethane, 13-16% by weight of CO2 and 7- 9 wt .-% water is produced, but it is not based on the provision of expandable polymer particles.
US7919538 (Dow) beschreibt einen Partikelschaum bestehend aus SAN und einem Additiv, welches Infrarotstrahlung abschirmt, zum Zweck einer verbesserten thermischen Isolierung, es werden keine expandierbaren Polymerpartikel angestrebt. US7919538 (Dow) describes a particle foam consisting of SAN and an additive that shields infrared radiation for the purpose of improved thermal insulation; expandable polymer particles are not sought.
US3945956 beschreibt ein Verfahren zur Herstellung expandierbarer Polymerpartikel, bei dem ein flüchtiges flüssiges Treibmittel in einer Hohlkugel aus Styrol und Acrylnitril eingeschlossen wird. Das Treibmittel ist in einem Polymerpartikel eingeschlossen, aber nicht homogen in einer Polymermatrix verteilt. Beim Expandieren solcher Polymerpartikel kommt es dadurch zu einem Schaum mit inhomogen verteilten Hohlräumen. US3945956 describes a process for producing expandable polymer particles in which a volatile liquid blowing agent is enclosed in a hollow sphere made of styrene and acrylonitrile. The blowing agent is encapsulated in a polymer particle but not homogeneously distributed in a polymer matrix. When such polymer particles expand, this results in a foam with inhomogeneously distributed cavities.
US5480599 beschreibt ein Verfahren zur Herstellung von Partikelschäumen. Dabei kann das Treibmittel nach Expansion der Partikel zumindest teilweise wiedergewonnen werden. Das Verfahren stellt jedoch nur expandierte Polymerpartikel bereit, keine expandierbaren Partikel. In US5049328 wird ein Verfahren zur Schaumherstellung ohne organische Treibmittel beschrieben. Als Treibmittel finden nur Inertgase wie CO2, Stickstoff oder Luft Verwendung. Das Verfahren ist nicht geeignet, expandierbare Polymerpartikel bereitzustellen, die eine gewisse Zeit (z.B. Tage, Wochen, Monate) lagerfähig sind. Die aus kleinen Molekülen bestehenden Gase können ggf. schnell aus der Polymermasse entweichen. US5480599 describes a process for producing particle foams. The propellant can be at least partially recovered after expansion of the particles. However, the process only provides expanded polymer particles, not expandable particles. US5049328 describes a process for producing foam without organic blowing agents. Only inert gases such as CO2, nitrogen or air are used as propellants. The process is not suitable for providing expandable polymer particles that can be stored for a certain period of time (eg days, weeks, months). the gases consisting of small molecules can escape quickly from the polymer mass if necessary.
Es besteht ein hoher Bedarf an einem Verfahren zur Bereitstellung expandierbarer Polymerpartikel, die eine gewisse Zeit gelagert und gegebenenfalls mit einem minimalen Aufwand transportiert werden können und darüber hinaus lediglich aus einer einzigen Polymerklasse bestehen, um das Recycling zu vereinfachen. Darüber hinaus besteht Bedarf an expandierbaren Polymerpartikeln, in denen nach der Expansion die Hohlräume weitestgehend homogen verteilt sind und in denen eine feinzellige Schaumstruktur vorliegt. Darüber hinaus sollen sich aus den expandierbaren Polymerpartikeln Formteile mit ausreichend guten mechanischen Eigenschaften erzeugen lassen. There is a great need for a method of providing expandable polymer particles that can be stored for a certain period of time and, if necessary, transported with a minimum of effort and, moreover, only consist of a single polymer class in order to simplify recycling. In addition, there is a need for expandable polymer particles in which the cavities are largely homogeneously distributed after expansion and in which there is a fine-celled foam structure. In addition, it should be possible to produce moldings with sufficiently good mechanical properties from the expandable polymer particles.
Eine Aufgabe der vorliegenden Erfindung ist daher die Bereitstellung expandierbarer, thermoplastischer Polymerpartikel mit geringem Treibmittelverlust und hohem Expansionsvermögen, die (auch nach der Verarbeitung) ohne hohen technischen Aufwand recycelt werden können und die zu Partikelschaumstoffen mit hoher Steifigkeit und guter Elastizität verarbeitet werden können, sowie ein Verfahren zu deren Herstellung. An object of the present invention is therefore to provide expandable, thermoplastic polymer particles with low loss of blowing agent and high expansion capacity, which (even after processing) can be recycled without great technical effort and which can be processed into particle foams with high rigidity and good elasticity, and a Process for their manufacture.
Überraschend wurde gefunden, dass sich diese Aufgabe durch das Herstellen der erfindungsgemäßen expandierbaren, thermoplastischen Polymerpartikel lösen lässt. Surprisingly, it was found that this object can be achieved by producing the expandable, thermoplastic polymer particles according to the invention.
Die expandierbaren, thermoplastischen Polymerpartikel enthalten, bzw. vorzugsweise bestehen aus: The expandable, thermoplastic polymer particles contain or preferably consist of:
A) 87 bis 99 Gew.-%, bevorzugt 91 bis 97 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Styrolpolymere (A), wobei mindestens ein Styrolpolymer (A) kein Styrol-Homopolymer ist; A) 87 to 99% by weight, preferably 91 to 97% by weight, based on the total weight of (A), (B) and (C), of one or more styrene polymers (A), where at least one styrene polymer (A ) is not a styrene homopolymer;
B) 1 bis 10 Gew.-%, bevorzugt 3 bis 7 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Treibmittel (B); B) 1 to 10% by weight, preferably 3 to 7% by weight, based on the total weight of (A), (B) and (C), of one or more blowing agents (B);
C) 0 bis 3 Gew.-%, bevorzugt 0,1 bis 2 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Keimbildner oder Nukleierungsmittel (C); und optional einen oder mehrere, weitere Zusatzstoffe (Z) in einer Menge, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigt. C) 0 to 3% by weight, preferably 0.1 to 2% by weight, based on the total weight of (A), (B) and (C), of one or more nucleating agents or nucleating agents (C); and optionally one or more further additives (Z) in an amount which does not impair the formation of domains and the resulting foam structure.
Dabei enthalten die expandierbaren, thermoplastischen Polymerpartikel neben dem einen oder den mehreren Styrolpolymeren (A) i.d.R. keine weiteren Polymere; wobei die Styrolpolymere (A) untereinander mischbar sind, wenn die expandierbaren, thermoplastischen Polymerpartikel mehrere Styrolpolymere (A) enthalten; und wobei die expandierbaren, thermoplastischen Polymerpartikel thermoplastisch rezyklier- bar sind. Der Begriff „thermoplastisch rezyklierbar“ bedeutet in der vorliegenden Beschreibung, dass die expandierbaren, thermoplastischen Polymerpartikel gut (ohne hohen technischen Aufwand) zum Recycling geeignet sind, z.B. in einem mechanischen Recyclingverfahren. Eine gute Eignung zum Recycling ist bei Styrolpolymeren insbesondere dann gegeben, wenn das Styrolpolymer (A) aus nur einer Polymerklasse besteht, oder, wenn die mehreren Styrolpolymere (A) aus solchen Polymerklassen bestehen, die miteinander gut mischbar sind, wie z.B. SAN, AMSAN, ABS und ASA. The expandable, thermoplastic polymer particles generally contain no further polymers apart from the one or more styrene polymers (A); where the styrene polymers (A) are miscible with one another if the expandable, thermoplastic polymer particles contain a plurality of styrene polymers (A); and wherein the expandable, thermoplastic polymer particles are thermoplastically recyclable. In the present description, the term “thermoplastically recyclable” means that the expandable, thermoplastic polymer particles are well suited (without high technical complexity) for recycling, for example in a mechanical recycling process. Styrene polymers are particularly suitable for recycling if the styrene polymer (A) consists of only one polymer class, or if the several styrene polymers (A) consist of polymer classes that are readily miscible with one another, such as SAN, AMSAN, ABS and ASA.
In einer Ausführungsform besteht das Styrolpolymer (A) nur aus einer Polymerklasse, wie z.B. SAN, AMSAN, ABS und ASA. In dieser Ausführungsform lassen sich die erfindungsgemäßen expandierbaren Polymerpartikel besonders gut recyceln, zum Beispiel in mechanischen Recyclingverfahren. In einer weiteren Ausführungsform besteht das Styrolpolymer (A) aus solchen Polymerklassen, die miteinander mischbar sind. Auch dann ist eine gute Fähigkeit bzw. Eignung zum Recycling gegeben, z.B. in mechanischen Recyclingverfahren. Gute Mischbarkeit zeigt sich z.B. daran, dass bei der Verarbeitungstemperatur (z.B. 200-260 °C) nicht zwei oder mehrere Phasen gebildet werden. In one embodiment, the styrenic polymer (A) consists of only one class of polymers such as SAN, AMSAN, ABS and ASA. In this embodiment, the expandable polymer particles according to the invention can be recycled particularly well, for example in mechanical recycling processes. In a further embodiment, the styrene polymer (A) consists of polymer classes which are miscible with one another. Even then, there is a good ability or suitability for recycling, e.g. in mechanical recycling processes. Good miscibility is shown, for example, by the fact that two or more phases are not formed at the processing temperature (e.g. 200-260 °C).
Vorzugsweise ist das Treibmittel (B) in den expandierbaren, thermoplastischen Polymerpartikeln homogen in einer Polymermatrix aus dem einen oder mehreren der Styrol-polymere (A) verteilt. The blowing agent (B) is preferably distributed homogeneously in the expandable, thermoplastic polymer particles in a polymer matrix composed of one or more of the styrene polymers (A).
Die expandierbaren thermoplastischen Polymerpartikel enthalten 87 bis 99 Gew.-%, bevorzugt 91 bis 97 Gew.-%, besonders bevorzugt 93,5 bis 97 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Styrolpolymeren (A), welche beispielsweise ausgewählt sind aus der Gruppe bestehend aus Styrol-Acrylnitril-Copo- lymeren (SAN), Acrylnitril-Butadien-Styrol-Copolymeren (ABS), Acrylat-Styrol-Acrylnitril- Copolymeren (ASA), Methylmethacrylat-Acrylnitril-Butadien-Styrol-Copolymeren (MABS), Methylmethacrylat-Butadien-Styrol-Copolymeren (MBS), a(alpha)-Methylsty- rol-Acrylnitril-Copolymeren (AMSAN), Styrol-Methylmethacrylat-Copolymeren (SMMA), amorphem Polystyrol (PS) und schlagzäh modifiziertem Polystyrol (HIPS). Bevorzugt ist das Styrolpolymer (A) ausgewählt aus der Gruppe bestehend aus Styrol-Acrylnitril-Co- polymeren (SAN), Acrylnitril-Butadien-Styrol-Copolymeren (ABS) oder Acrylnitril-Styrol- Acrylat-Copolymeren (ASA). The expandable thermoplastic polymer particles contain 87 to 99% by weight, preferably 91 to 97% by weight, particularly preferably 93.5 to 97% by weight, based on the total weight of (A), (B) and (C) , one or more styrene polymers (A), which are selected, for example, from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene copolymers (ABS), acrylate-styrene-acrylonitrile copolymers (ASA) , methyl methacrylate-acrylonitrile-butadiene-styrene copolymers (MABS), methyl methacrylate-butadiene-styrene copolymers (MBS), a(alpha)-methylstyrene-acrylonitrile copolymers (AMSAN), styrene-methyl methacrylate copolymers (SMMA), amorphous polystyrene (PS) and impact modified polystyrene (HIPS). The styrene polymer (A) is preferably selected from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene copolymers (ABS) or acrylonitrile-styrene-acrylate copolymers (ASA).
Besonders bevorzugt werden Styrol-Acrylnitril-Copolymere, Acrylnitril-Butadien-Styrol- Copolymere oder Acrylnitril-Styrol-Acrylat-Copolymere mit einer Schmelzevolumenrate MVR (220°C/10 kg) nach ISO 1133 im Bereich von 1 bis 12 cm3/10 min, bevorzugt im Bereich von 1 bis 10 cm3/10 min. In einer bevorzugten Ausführungsform enthält das Styrolpolymer (A) kein Styrol-Homopolymer. In einer weiteren bevorzugten Ausführungsform enthalten die expandierbaren, thermoplastischen Polymerpartikel keine anderen Polymere als das Styrolpolymer (A), welches vorzugsweise kein Styrol-Homopolymer enthält. Die Komponente (A) besteht z.B. aus SAN, ABS, ASA und oder Mischungen enthaltend mindestens zwei dieser Polymere. Im Falle von ABS als Komponente (A) wird vorzugsweise auch mindestens eine Komponente (C) verwendet. Styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers or acrylonitrile-styrene-acrylate copolymers with a melt volume rate MVR (220° C./10 kg) according to ISO 1133 in the range from 1 to 12 cm 3 /10 min are particularly preferred , preferably in the range from 1 to 10 cm 3 /10 min. In a preferred embodiment, the styrene polymer (A) contains no styrene homopolymer. In a further preferred embodiment, the expandable, thermoplastic polymer particles contain no other polymers than the styrene polymer (A), which preferably contains no styrene homopolymer. Component (A) consists, for example, of SAN, ABS, ASA and/or mixtures containing at least two of these polymers. In the case of ABS as component (A), at least one component (C) is preferably also used.
Als Treibmittel (Komponente (B)) enthalten die expandierbaren, thermoplastischen Polymerpartikel 1 bis 10 Gew.-%, bevorzugt 3 bis 7 Gew.-%, besonders bevorzugt 4 bis 6 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer physikalischer Treibmittel, wie CO2, aliphatische Cs-bis Cs-Kohlenwasserstoffe, Alkohole, Ketone, Ether oder halogenierte Kohlenwasserstoffe, bevorzugt CO2 bzw. alternativ iso-Butan, n-Butan, iso-Pentan, n-Pentan (Sdp. 36°C), cyclo-Pentan, oder Gemische daraus. As a blowing agent (component (B)), the expandable, thermoplastic polymer particles contain 1 to 10% by weight, preferably 3 to 7% by weight, particularly preferably 4 to 6% by weight, based on the total weight of (A), (B) and (C), one or more physical blowing agents, such as CO2, aliphatic Cs to Cs hydrocarbons, alcohols, ketones, ethers or halogenated hydrocarbons, preferably CO2 or alternatively isobutane, n-butane, isopentane , n-pentane (bp 36°C), cyclopentane, or mixtures thereof.
Als Komponente (C) enthalten die expandierbaren, thermoplastischen Polymerpartikel 0 bis 3 Gew.-%, bevorzugt 0 bis 2 Gew.-%, oftmals 0,1 bis 2 Gew.-%, besonders bevorzugt 0,1 bis 0,8 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Keimbildner oder Nukleierungsmittel, beispielsweise Talkum, Aluminiumoxid oder Siliciumdioxid. As component (C), the expandable, thermoplastic polymer particles contain 0 to 3% by weight, preferably 0 to 2% by weight, often 0.1 to 2% by weight, particularly preferably 0.1 to 0.8% by weight. -%, based on the total weight of (A), (B) and (C), of one or more nucleating or nucleating agents, for example talc, alumina or silica.
Des Weiteren können den expandierbaren, thermoplastischen Polymerpartikeln weitere Zusatzstoffe (Z) wie beispielsweise Weichmacher, Flammschutzmittel, lösliche und unlösliche anorganische und/oder organische Farbstoffe und Pigmente, Füllstoffe, Co- T reibmittel oder andere Additive in Mengen zugesetzt werden, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigen (z.B. im Bereich 0,1 bis 5 Gew.-%, Bereich 0,1 bis 2 Gew.-%, bevorzugt 0,1 bis 0,9 Gew.-%, bezogen auf die gesamte Zusammensetzung). Furthermore, other additives (Z) such as plasticizers, flame retardants, soluble and insoluble inorganic and / or organic dyes and pigments, fillers, co-blowing agents or other additives can be added in amounts to the expandable, thermoplastic polymer particles, which the domain formation and from it do not impair the resulting foam structure (e.g. in the range from 0.1 to 5% by weight, in the range from 0.1 to 2% by weight, preferably from 0.1 to 0.9% by weight, based on the total composition).
Als Additive in den expandierbaren, thermoplastischen Polymerpartikeln können übliche Kunststoff-Additive und -Hilfsstoffe enthalten sein. Beispielshaft kann ein Additiv oder ein Hilfsstoff ausgewählt sein aus der Gruppe bestehend aus Antioxidantien, UV-Stabi- lisatoren, Peroxidzerstörern, Antistatika, Gleitmitteln, Entformungsmitteln, Flammschutzmitteln, Füll- oder Verstärkerstoffen (Glasfasern, Kohlefasern, etc.), Farbmitteln und Kombinationen aus zwei oder mehr daraus. Customary plastic additives and auxiliaries can be present as additives in the expandable, thermoplastic polymer particles. For example, an additive or an auxiliary can be selected from the group consisting of antioxidants, UV stabilizers, peroxide destroyers, antistatic agents, lubricants, mold release agents, flame retardants, fillers or reinforcing materials (glass fibers, carbon fibers, etc.), colorants and combinations of two or more of it.
Als Beispiele für Oxidationsverzögerer und Wärmestabilisatoren werden Halogenide von Metallen der Gruppe I des Periodensystems, z.B. Natrium-, Kalium- und/oder Lithiumhalogenide, ggf. in Verbindung mit Kupfer-(l)-Halogeniden, z.B. Chloriden, Bromiden, Jodiden, sterisch gehinderte Phenole, Hydrochinone, substituierte Vertreter dieser Gruppen und deren Mischungen in Konzentrationen bis zu 1 Gew.-%, bezogen auf das Gesamtgewicht der expandierbaren, thermoplastischen Polymerpartikel, genannt. Examples of oxidation retardants and heat stabilizers are halides of metals from group I of the periodic table, for example sodium, potassium and/or lithium halides, optionally in combination with copper(I) halides, for example chlorides, bromides, Iodides, sterically hindered phenols, hydroquinones, substituted representatives of these groups and mixtures thereof in concentrations of up to 1% by weight, based on the total weight of the expandable, thermoplastic polymer particles.
Als UV-Stabilisatoren, die im Allgemeinen in Mengen bis zu 2 Gew.-%, oftmals 0,1-1 , 5 Gew.-%, bezogen auf das Gesamtgewicht der expandierbaren, thermoplastischen Polymerpartikel enthalten sind, werden verschiedene substituierte Resorcine, Salicylate, Benzotriazole und Benzophenone genannt. Various substituted resorcinols, salicylates, called benzotriazoles and benzophenones.
Weiterhin können organische Farbstoffe wie Nigrosin, Pigmente wie Titandioxid, Phthalocyanine, Ultramarinblau und Ruß als Farbstoffe in den thermoplastischen Polymerpartikeln enthalten sein, sowie faser- und pulverförmige Füllstoffe und Verstärkungsmittel. Beispiele für letztere sind Kohlenstofffasern, Glasfasern, amorphe Kieselsäure, Calciumsilicat (Wollastonit), Aluminiumsilicat, Magnesiumcarbonat, Kaolin, Kreide, gepulverter Quarz, Glimmer und Feldspat. Furthermore, organic dyes such as nigrosine, pigments such as titanium dioxide, phthalocyanines, ultramarine blue and carbon black can be contained as dyes in the thermoplastic polymer particles, as well as fibrous and pulverulent fillers and reinforcing agents. Examples of the latter are carbon fibers, glass fibers, amorphous silica, calcium silicate (wollastonite), aluminum silicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica and feldspar.
Gleit- und Entformungsmittel, welche in der Regel in Mengen bis zu 1 Gew.-%, oftmals 0,1 -0,8 Gew.-%, bezogen auf das Gesamtgewicht der expandierbaren, thermoplastischen Polymerpartikel, eingesetzt werden können, sind z.B. langkettige Fettsäuren wie Stearinsäure oder Behensäure, deren Salze (z.B. Ca- oder Zn-Stearat) oder Ester (z.B. Stearylstearat oder Pentaerythrittetrastearat) sowie Amidderivate (z.B. Ethylenbisstea- rylamid). Long-chain fatty acids are examples of lubricants and mold release agents, which can generally be used in amounts of up to 1% by weight, often 0.1-0.8% by weight, based on the total weight of the expandable, thermoplastic polymer particles such as stearic acid or behenic acid, their salts (e.g. Ca or Zn stearate) or esters (e.g. stearyl stearate or pentaerythritol tetrastearate) and amide derivatives (e.g. ethylenebisstearylamide).
Weiterhin können Antiblockmittel auf mineralischer Basis in Mengen bis zu 0,1 Gew.-%, bezogen auf das Gesamtgewicht der expandierbaren, thermoplastischen Polymerpartikel, enthalten sein. Als Beispiele seien amorphe oder kristalline Kieselsäure, Calciumcarbonat oder Aluminiumsilikat genannt. Mineral-based antiblocking agents can also be present in amounts of up to 0.1% by weight, based on the total weight of the expandable, thermoplastic polymer particles. Examples which may be mentioned are amorphous or crystalline silica, calcium carbonate or aluminum silicate.
Als Verarbeitungshilfsmittel kann beispielsweise Mineralöl, vorzugsweise medizinisches Weißöl, in Mengen bis zu 5 Gew.-%, vorzugsweise bis zu 2 Gew.-%, insbesondere 0,1 bis 2 Gew.-%, bezogen auf das Gesamtgewicht der expandierbaren, thermoplastischen Polymerpartikel, enthalten sein. Mineral oil, preferably medicinal white oil, can be used as a processing aid in amounts of up to 5% by weight, preferably up to 2% by weight, in particular 0.1 to 2% by weight, based on the total weight of the expandable, thermoplastic polymer particles. be included.
Als Beispiele für Weichmacher seien Phthalsäuredioctylester, Phthalsäuredibenzylester, Phthalsäurebutylbenzylester, Kohlenwasserstofföle, N-(n-Butyl)benzolsulfonamid und o- und p-Tolylethylsulfonamid genannt. Weiterhin können alle für die jeweiligen Thermoplaste bekannten nicht-halogenhaltigen Flammschutzmittel enthalten sein, insbesondere solche auf Basis von Phosphorverbindungen. Examples of plasticizers which may be mentioned are dioctyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, hydrocarbon oils, N-(n-butyl)benzenesulfonamide and o- and p-tolylethylsulfonamide. Furthermore, all non-halogen-containing flame retardants known for the respective thermoplastics can be present, in particular those based on phosphorus compounds.
In einer Ausführungsform bestehen die expandierbaren, thermoplastischen Polymerpartikel aus dem Styrolpolymeren (A) und dem Treibmittel (B). In einer weiteren Ausführungsform bestehen die expandierbaren, thermoplastischen Polymerpartikel aus dem Styrol polymeren (A), dem Treibmittel (B) und dem Keimbildner oder Nukleierungsmittel (C). In einerweiteren Ausführungsform bestehen die expandierbaren, thermoplastischen Polymerpartikel aus dem Styrolpolymeren (A), dem Treibmittel (B), dem Keimbildner oder Nukleierungsmittel (C) und weiteren Zusatzstoffen (Z) in Mengen, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigen. In one embodiment, the expandable, thermoplastic polymer particles consist of the styrene polymer (A) and the blowing agent (B). In a further embodiment, the expandable, thermoplastic polymer particles consist of the styrene polymer (A), the blowing agent (B) and the nucleating agent or nucleating agent (C). In a further embodiment, the expandable, thermoplastic polymer particles consist of the styrene polymer (A), the blowing agent (B), the nucleating agent or nucleating agent (C) and other additives (Z) in amounts which do not impair domain formation and the resulting foam structure.
Wenn das Styrolpolymer (A) ein Acrylnitril-Butadien-Styrol-Copolymer (ABS) ist, ist es von Vorteil, wenn ein Keimbildner oder Nukleierungsmittel (C) in den expandierbaren, thermoplastischen Polymerpartikeln enthalten ist. If the styrene polymer (A) is an acrylonitrile-butadiene-styrene copolymer (ABS), it is advantageous if a nucleating agent (C) is contained in the expandable, thermoplastic polymer particles.
Ein Gegenstand der Erfindung ist ein Verfahren zur Herstellung expandierbarer, thermoplastischer Polymerpartikel, umfassend die Schritte: a) Versetzen eines Styrolpolymeren (A) mit einem Treibmittel (B) und optional einem Keimbildner oder Nukleierungsmittel (C), und optional Zusatzstoffen in Mengen, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigen, so dass eine Polymermischung (I) entsteht. b) Vorexpandieren der Polymermischung (I). One subject of the invention is a process for producing expandable, thermoplastic polymer particles, comprising the steps of: a) mixing a styrene polymer (A) with a blowing agent (B) and optionally a nucleating agent or nucleating agent (C), and optionally additives in amounts that Do not affect domain formation and resulting foam structure, so that a polymer mixture (I) is formed. b) pre-expanding the polymer mixture (I).
In einer Ausführungsform werden in dem Verfahren nur das Styrolpolymer (A) und das Treibmittel (B) als Ausgangsstoffe eingesetzt. In einerweiteren Ausführungsform werden in dem Verfahren nur das Styrolpolymer (A), das Treibmittel (B) und der Keimbildner oder das Nukleierungsmittel (C) eingesetzt. In einer weiteren Ausführungsform werden in dem Verfahren nur das Styrolpolymer (A), das Treibmittel (B), der Keimbildner oder das Nukleierungsmittel (C) und weitere Zusatzstoffen (Z) in Mengen, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigen, eingesetzt. In one embodiment, only the styrenic polymer (A) and the blowing agent (B) are used as starting materials in the process. In another embodiment, only the styrenic polymer (A), the blowing agent (B) and the nucleating agent or nucleating agent (C) are used in the process. In a further embodiment, only the styrene polymer (A), the blowing agent (B), the nucleating agent or the nucleating agent (C) and other additives (Z) are used in the process in amounts which do not impair domain formation and the resulting foam structure.
Bevorzugt findet mindestens Schritt b), besonders bevorzugt Schritte a) und b) unter einem Druck statt, der den Atmosphärendruck übersteigt. In einer Ausführungsform der Erfindung finden die Prozessschritte a) und b) in einem Extruder mit anschließender Unterwassergranulation bei einem Druck im Bereich von 1 ,5 bis 11 bar statt. At least step b), particularly preferably steps a) and b), preferably takes place under a pressure which exceeds atmospheric pressure. In one embodiment of the invention, process steps a) and b) take place in an extruder with subsequent underwater granulation at a pressure in the range from 1.5 to 11 bar.
In einer weiteren Ausführungsform finden die Prozessschritte a) und b) in einem Autoklaven statt. Dabei wird das granulierte Styrolpolymer (A), das optional mit einem Nukleierungsmittel (C) und optional mit weiteren Zusatzstoffen versetzt wurde, unter Druck mit dem Treibmittel (B) zu expandierbaren, thermoplastischen Polymerpartikeln imprägniert. Diese können anschließend isoliert werden oder als vorgeschäumte Schaumstoffpartikel direkt durch Druckentspannung erhalten werden. In a further embodiment, process steps a) and b) take place in an autoclave. In this process, the granulated styrene polymer (A), to which a nucleating agent (C) and optionally further additives have optionally been added, is impregnated under pressure with the blowing agent (B) to form expandable, thermoplastic polymer particles. These can then be isolated or obtained as prefoamed foam particles directly by decompression.
In einer weiteren Ausführungsform wird das Styrolpolymer (A) in einer Suspension synthetisiert und mit einem physikalischen Treibmittel beaufschlagt. In a further embodiment, the styrene polymer (A) is synthesized in a suspension and treated with a physical blowing agent.
Besonders bevorzugt ist ein kontinuierliches Verfahren, bei dem im Prozessschritt a) ein thermoplastisches Styrolpolymer (A), beispielsweise SAN, ABS oder ASA, gegebenenfalls vermischt mit dem Nukleierungsmittel (C) und optional den weiteren Zusatzstoffen, in einem Doppelschneckenextruder aufgeschmolzen und mit dem Treibmittel (B) imprägniert wird. Die treibmittelbeladene Schmelze kann anschließend in Prozessschritt b) durch eine entsprechende Düse zu Schaumstoffplatten, -strängen oder -partikeln extrudiert und geschnitten werden. Dabei ist eine bevorzugte Ausführungsform die Extrusion durch eine Mikrolochplatte mit einem oder, in der Regel, mehreren Löchern mit einem Lochdurchmesser von 0,1 bis 2,4 mm, bevorzugt 0,2 bis 1 ,2 mm, besonders bevorzugt von 0,5 bis 0,8 mm, so dass Partikel entstehen. In einer bevorzugten Ausführungsform wird die aus der Mikrolochplatte austretende Schmelze in einen Wasserstrom geführt, wo die Schmelze durch eine geeignete Vorrichtung in einzelne Partikel zerschnitten wird. Die Einstellung des geeigneten Gegendrucks und einer geeigneten Temperatur im Wasserstrom dieser sogenannten Unterwassergranulation ermöglicht eine gezielte Herstellung von expandierbaren Polymerpartikeln. A continuous process is particularly preferred in which, in process step a), a thermoplastic styrene polymer (A), for example SAN, ABS or ASA, optionally mixed with the nucleating agent (C) and optionally the other additives, is melted in a twin-screw extruder and mixed with the blowing agent ( B) is impregnated. The melt loaded with blowing agent can then be extruded and cut in process step b) through an appropriate nozzle to form foam sheets, strands or particles. A preferred embodiment is extrusion through a microperforated plate with one or, as a rule, several holes with a hole diameter of 0.1 to 2.4 mm, preferably 0.2 to 1.2 mm, particularly preferably from 0.5 to 0.8 mm, so that particles are formed. In a preferred embodiment, the melt emerging from the microperforated plate is fed into a stream of water, where the melt is cut up into individual particles by a suitable device. The setting of the appropriate back pressure and a suitable temperature in the water flow of this so-called underwater granulation enables a targeted production of expandable polymer particles.
Die erfindungsgemäßen expandierbaren, thermoplastischen Polymerpartikel haben bevorzugt einen mittleren Partikeldurchmesser im Bereich von 0,1 bis 3 mm, bevorzugt von 0,3 bis 2 mm, besonders bevorzugt von 0,5 bis 1 mm. Expandierbare Polymerpartikel mit enger Partikelgrößenverteilung und einem mittleren Partikeldurchmesser im genannten Bereich führen zu einer besseren Ausfüllung der Form beim Verschweißen der Polymerpartikel zu einem Formteil. Sie ermöglichen eine filigranere Formteilgestaltung und eine bessere Formteiloberfläche. In einer weiteren bevorzugten Ausführungsform werden die expandierbaren, thermoplastischen Polymerpartikel vorgeschäumt. Bevorzugt werden die erhaltenen expandierbaren Polymerpartikel auf einen mittleren Durchmesser im Bereich von 0,2 bis 10 mm aufgeschäumt. The expandable, thermoplastic polymer particles according to the invention preferably have an average particle diameter in the range from 0.1 to 3 mm, preferably from 0.3 to 2 mm, particularly preferably from 0.5 to 1 mm. Expandable polymer particles with a narrow particle size distribution and an average particle diameter in the range mentioned lead to better filling of the mold when the polymer particles are welded to form a molded part. They enable a more filigree part design and a better part surface. In a further preferred embodiment, the expandable, thermoplastic polymer particles are prefoamed. The expandable polymer particles obtained are preferably foamed to an average diameter in the range from 0.2 to 10 mm.
Die spezifische Dichte der expandierten Polymerpartikel liegt bevorzugt im Bereich von 10 bis 250 g/L, besonders bevorzugt bei 20 bis 200 g/L, besonders bevorzugt bei 25 bis 150 g/L und insbesondere bevorzugt bei 30-100 g/L. The specific density of the expanded polymer particles is preferably in the range from 10 to 250 g/l, particularly preferably 20 to 200 g/l, particularly preferably 25 to 150 g/l and particularly preferably 30-100 g/l.
Die erfindungsgemäßen expandierbaren, thermoplastischen Polymerpartikel können in eine Form gefüllt werden, die dann geschlossen und von Heißluft oder Wasserdampf durchströmt und so erwärmt wird. Dabei expandieren die Polymerpartikel weiter, idealerweise bis zur vollständigen Füllung der Kavität, und bilden so Schaumstoffformkörper. Hierbei wird der Verarbeitungsdruck so niedrig gewählt, dass die Domänenstruktur in den Zellmembranen erhalten bleibt. Üblicherweise liegt der Druck im Bereich von 0,5 bis 1 ,0 bar. The expandable, thermoplastic polymer particles according to the invention can be filled into a mold which is then closed and hot air or steam flows through it and is thus heated. The polymer particles expand further, ideally until the cavity is completely filled, and thus form foam moldings. Here, the processing pressure is chosen so low that the domain structure in the cell membranes is preserved. The pressure is usually in the range from 0.5 to 1.0 bar.
Ein weiterer Gegenstand der Erfindung ist demnach die Verwendung expandierbarer, thermoplastischer Polymerpartikel wie oben beschrieben, in einem Schaumstoffformkörper, gebildet durch Verschweißen der expandierbaren Polymerpartikel mittels Heißluft oder Wasserdampf. Vorzugsweise weist das Formteil eine spezifische Dichte von weniger als 250 g/L, bevorzugt von weniger als 150 g/L auf. Auch die aus den expandierbaren, thermoplastischen Polymerpartikel gewonnenen Schaumstoffe bzw. Formkörper sind Gegenstand der Erfindung. A further object of the invention is accordingly the use of expandable, thermoplastic polymer particles as described above in a foam molding formed by welding the expandable polymer particles by means of hot air or steam. The molding preferably has a specific density of less than 250 g/l, preferably less than 150 g/l. The invention also relates to the foams or moldings obtained from the expandable, thermoplastic polymer particles.
Die Erfindung wird durch die folgenden Beispiele und Ansprüche näher illustriert. The invention is further illustrated by the following examples and claims.
In einem gleichläufig rotierenden Doppelschneckenextruder (Typ ZK25P, Hersteller Collin GmbH) mit einem Schneckendurchmesser 30 mm und einem Verhältnis von Länge zu Durchmesser von 42 wurden die Polymere (A) mit dem Treibmittel (B) und gegebenenfalls dem Nukleierungsmittel (C) bei 200-240 °C aufgeschmolzen und so homogen gemischt. In a co-rotating twin-screw extruder (type ZK25P, manufacturer Collin GmbH) with a screw diameter of 30 mm and a length-to-diameter ratio of 42, the polymers (A) were mixed with the blowing agent (B) and optionally the nucleating agent (C) at 200-240 °C melted and mixed homogeneously.
Anschließend wurde die so erhaltene Polymermischung (I) in einem Einschnecken- Extruder (Typ E 45 M, Hersteller Collin GmbH) mit einem Schneckendurchmesser 45 mm und einem Verhältnis von Länge zu Durchmesser von 30 abgekühlt und die Schmelze durch eine beheizte Lochplatte extrudiert. Der Polymerstrang wurde mittels Unterwassergranulierung abgeschlagen, so dass ein treibmittelbeladenes Minigranulat mit enger Teilchengrößenverteilung erhalten wurde. Anschließend wurde das treibmittelbeladene Minigranulat in einem X-Line 3-Vorschäu- mer (Hersteller Kurtz GmbH) vorgeschäumt. Die vorgeschäumten Polymerpartikel wurden in einem Formteilautomaten TVZ 162/100 PP (Hersteller Teubert Maschinenbau GmbH) bei ca. 120-125 °C verschweißt, um Prüfkörper für die Messung der thermischen und mechanischen Eigenschaften herzustellen. The polymer mixture (I) obtained in this way was then cooled in a single-screw extruder (type E 45 M, manufacturer Collin GmbH) with a screw diameter of 45 mm and a length-to-diameter ratio of 30, and the melt was extruded through a heated perforated plate. The polymer strand was cut off by means of underwater pelletizing, so that a propellant-loaded minigranulate with a narrow particle size distribution was obtained. The minigranules loaded with blowing agent were then prefoamed in an X-Line 3 prefoamer (manufacturer Kurtz GmbH). The pre-foamed polymer particles were welded in a TVZ 162/100 PP molding machine (manufacturer Teubert Maschinenbau GmbH) at approx. 120-125 °C in order to produce test specimens for measuring the thermal and mechanical properties.
Die Dichte der vorgeschäumten Partikel wurde mit einer AG245-Dichtewaage (Hersteller Mettler Toledo) gemäß ISO 1183 bestimmt. The density of the prefoamed particles was determined in accordance with ISO 1183 using an AG245 density balance (manufacturer: Mettler Toledo).
Die thermische Charakterisierung der Prüfkörper erfolgte gemäß DIN EN 12667 mit einer Wärmeflussmessplattenapparatur Typ HMF Lambda Small (Hersteller Netzsch) anhand von Prüfkörpern mit den Abmessungen 200 x 200 x20 mm und einem Temperaturgefälle von 20 K. The thermal characterization of the test specimens was carried out according to DIN EN 12667 with a heat flow measuring plate apparatus type HMF Lambda Small (manufacturer Netzsch) using test specimens with the dimensions 200 x 200 x 20 mm and a temperature gradient of 20 K.
Die mechanische Charakterisierung der Prüfkörper erfolgte mittels 3-Punkt-Biegetest mit einer Universalprüfmaschine 1485 (Hersteller Zwick Roell) gemäß ISO 1209 an Prüfkörpern mit den Abmessungen 120 x 25 x 20 mm, mit einem Druck von 0,5 N und einer Prüfgeschwindigkeit von 10 mm/min. The mechanical characterization of the test specimens was carried out using a 3-point bending test with a universal testing machine 1485 (manufacturer Zwick Roell) in accordance with ISO 1209 on test specimens measuring 120 x 25 x 20 mm, with a pressure of 0.5 N and a test speed of 10 mm /min
Die Ergebnisse sind in den nachfolgenden Tabellen 1 und 2 dargestellt. The results are shown in Tables 1 and 2 below.
Es ist zu erkennen, dass Prüfkörper aus den erfindungsgemäßen Zusammensetzungen (Versuche 1 bis 3) bessere mechanische Eigenschaften aufweisen als die Prüfkörper aus der nicht erfindungsgemäßen Zusammensetzung (Vergleichsversuch 4). It can be seen that test specimens from the compositions according to the invention (tests 1 to 3) have better mechanical properties than the test specimens from the composition not according to the invention (comparative test 4).
Tabelle 1 : Eingesetzte Materialien Table 1: Materials used
Statt der genannten handelsüblichen SAN- und ABS-Copolymer-Produkte können auch weitere Styrol-Copolymere, wie ASA oder AMSAM zum Einsatz kommen. Auch können weitere Zusatzstoffe (Z) verwendet werden. Tabelle 2: Vergleich der durchgeführten Experimente Instead of the commercially available SAN and ABS copolymer products mentioned, other styrene copolymers such as ASA or AMSAM can also be used. Other additives (Z) can also be used. Table 2: Comparison of the experiments carried out
Die erfindungsgemäßen Zusammensetzungen (Versuche 1 bis 3) können gut gelagert werden und führen in Prüfkörpern zu einem besseren Biegemodul als die Körper aus der nicht erfindungsgemäßen Zusammensetzung (Vergleich 4). The compositions according to the invention (experiments 1 to 3) can be stored well and lead to a better flexural modulus in test specimens than the bodies made from the composition not according to the invention (comparison 4).
Analoge Ergebnisse lassen sich statt mit n-Pentan auch mit anderen Treibmitteln wie z.B. iso-Butan, n-Butan, iso-Pentan und cyclo-Pentan erzielen. Similar results can also be achieved with other blowing agents such as isobutane, n-butane, isopentane and cyclopentane instead of n-pentane.
Die erhaltenen Polymerprodukte bzw. die Formkörper aus SAN bzw. ABS lassen sich ohne hohen Aufwand einem Recycling, z.B. unter Rückgewinnung von Styrol zuführen, was sie auch aus ökologischen Gründen interessant macht. The polymer products obtained or the moldings made of SAN or ABS can be recycled without great effort, e.g. with the recovery of styrene, which also makes them interesting for ecological reasons.

Claims

Patentansprüche patent claims
1. Expandierbare, thermoplastische Polymerpartikel enthaltend, 1. containing expandable, thermoplastic polymer particles,
A) 87 bis 99 Gew.-%, bevorzugt 91 bis 97 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Styrolpolymeren (A), wobei mindestens ein Styrolpolymer (A) kein Styrol-Homopolymer ist; A) 87 to 99% by weight, preferably 91 to 97% by weight, based on the total weight of (A), (B) and (C), of one or more styrene polymers (A), where at least one styrene polymer (A ) is not a styrene homopolymer;
B) 1 bis 10 Gew.-%, bevorzugt 3 bis 7 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Treibmittel (B); B) 1 to 10% by weight, preferably 3 to 7% by weight, based on the total weight of (A), (B) and (C), of one or more blowing agents (B);
C) 0 bis 3 Gew.-%, bevorzugt 0,1 bis 2 Gew.-%, bezogen auf das Gesamtgewicht von (A), (B) und (C), eines oder mehrerer Keimbildner oder Nukleierungsmittel (C); und optional einen oder mehrere weitere Zusatzstoffe (Z) in einer Menge, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigt; wobei die expandierbaren, thermoplastischen Polymerpartikel neben dem einen oder den mehreren Styrolpolymeren (A) keine weiteren Polymere enthalten; wobei die Styrolpolymere (A) untereinander mischbar sind, wenn die expandierbaren, thermoplastischen Polymerpartikel mehrere Styrol polymere (A) enthalten; und wobei die expandierbaren, thermoplastischen Polymerpartikel thermoplastisch rezyklier- bar sind. C) 0 to 3% by weight, preferably 0.1 to 2% by weight, based on the total weight of (A), (B) and (C), of one or more nucleating agents or nucleating agents (C); and optionally one or more further additives (Z) in an amount which does not impair the formation of domains and the resulting foam structure; where the expandable, thermoplastic polymer particles contain no other polymers apart from the one or more styrene polymers (A); where the styrene polymers (A) are miscible with one another if the expandable, thermoplastic polymer particles contain a plurality of styrene polymers (A); and wherein the expandable, thermoplastic polymer particles are thermoplastically recyclable.
2. Expandierbare, thermoplastische Polymerpartikel gemäß Anspruch 1 , dadurch gekennzeichnet, dass es sich bei dem einen oder den mehreren Styrolpolymeren (A) um mindestens ein Polymer ausgewählt aus der Gruppe bestehend aus Styrol-Acrylnitril- Copolymeren (SAN), Acrylnitril-Butadien-Styrol-Copolymeren (ABS), Acrylat-Styrol-Ac- rylnitril-Copolymeren (ASA), Methylmethacrylat-Acrylnitril-Butadien-Styrol-Copolymeren (MABS), Methylmethacrylat-Butadien-Styrol-Copolymeren (MBS), a(alpha)-Methylsty- rol-Acrylnitril-Copolymeren (AMSAN), Styrol-Methylmethacrylat-Copolymeren (SMMA), amorphem Polystyrol (PS), schlagzäh modifiziertem Polystyrol (HIPS) handelt. 2. Expandable, thermoplastic polymer particles according to claim 1, characterized in that the one or more styrene polymers (A) are at least one polymer selected from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene -copolymers (ABS), acrylate-styrene-acrylonitrile copolymers (ASA), methyl methacrylate-acrylonitrile-butadiene-styrene copolymers (MABS), methyl methacrylate-butadiene-styrene copolymers (MBS), a(alpha)-methylstyrene rol-acrylonitrile copolymers (AMSAN), styrene-methyl methacrylate copolymers (SMMA), amorphous polystyrene (PS), impact-modified polystyrene (HIPS).
3. Expandierbare, thermoplastische Polymerpartikel gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, dass es sich bei dem einen oder den mehreren Styrolpolymeren (A) um mindestens ein Polymer ausgewählt aus der Gruppe bestehend aus Styrol- Acrylnitril-Copolymeren (SAN), Acrylnitril-Butadien-Styrol-Copolymeren (ABS) und Ac- rylat-Styrol-Acrylnitril-Copolymeren (ASA) handelt. 3. Expandable, thermoplastic polymer particles according to claim 1 or 2, characterized in that the one or more styrene polymers (A) are at least one polymer selected from the group consisting of styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene -Styrene copolymers (ABS) and acrylate-styrene-acrylonitrile copolymers (ASA).
4. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass es sich bei dem einen oder den mehreren Styrolpolymeren (A) um mindestens ein Styrolpolymer handelt, welches einen Volumen- Schmelzflussindex, gemessen gemäß ISO 1133, bei 220 °C und mit einer Belastung von 10 kg, im Bereich von 1 bis 12 cm3/10 min., vorzugsweise im Bereich von 1 bis 10 cm3/10 min. aufweist. 4. Expandable, thermoplastic polymer particles according to any one of claims 1 to 3, characterized in that the one or more styrene polymers (A) is at least one styrene polymer which has a volume melt flow index, measured according to ISO 1133, at 220 ° C and with a load of 10 kg, in the range of 1 to 12 cm 3 /10 min, preferably in the range of 1 to 10 cm 3 /10 min.
5. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass es sich bei dem Treibmittel (B) um mindestens ein Treibmittel ausgewählt aus der Gruppe bestehend aus CO2, aliphatischen Cs-bis Cs- Kohlenwasserstoffen, Alkoholen, Ketonen, Ethern oder halogenierten Kohlenwasserstoffen, bevorzugt CO2, iso-Butan, n-Butan, iso-Pentan, n-Pentan, cyclo-Pentan handelt. 5. Expandable, thermoplastic polymer particles according to any one of claims 1 to 4, characterized in that the blowing agent (B) is at least one blowing agent selected from the group consisting of CO2, aliphatic Cs to Cs hydrocarbons, alcohols, ketones, Ethers or halogenated hydrocarbons, preferably CO2, isobutane, n-butane, isopentane, n-pentane, cyclopentane.
6. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass es sich bei dem Keimbildner oder Nukleierungsmittel (C) um mindestens ein Nukleierungsmittel ausgewählt aus der Gruppe bestehend aus Talkum, Aluminiumoxid oder Siliciumdioxid handelt. 6. Expandable, thermoplastic polymer particles according to any one of claims 1 to 5, characterized in that the nucleating agent or nucleating agent (C) is at least one nucleating agent selected from the group consisting of talc, aluminum oxide or silicon dioxide.
7. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass der mittlere Partikeldurchmesser der expandierbaren, thermoplastischen Polymerpartikel im nicht-vorgeschäumten Zustand im Bereich von 0,1 bis 3 mm, bevorzugt von 0,3 bis 2 mm, besonders bevorzugt von 0,5 bis 1 mm liegt. 7. Expandable, thermoplastic polymer particles according to one of claims 1 to 6, characterized in that the average particle diameter of the expandable, thermoplastic polymer particles in the non-prefoamed state is in the range from 0.1 to 3 mm, preferably from 0.3 to 2 mm. more preferably from 0.5 to 1 mm.
8. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass die Polymerpartikel auf einen mittleren Durchmesser von 0,2 bis 10 mm vorgeschäumt sind. 8. Expandable, thermoplastic polymer particles according to any one of claims 1 to 7, characterized in that the polymer particles are prefoamed to an average diameter of 0.2 to 10 mm.
9. Expandierbare, thermoplastische Polymerpartikel gemäß einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass das Treibmittel (B) homogen in einer Polymermatrix aus dem einen oder mehreren Styrolpolymeren (A) verteilt ist. 9. Expandable, thermoplastic polymer particles according to any one of claims 1 to 8, characterized in that the blowing agent (B) is distributed homogeneously in a polymer matrix of the one or more styrene polymers (A).
10. Verfahren zur Herstellung expandierbarer, thermoplastischer Polymerpartikel, gemäß einem der Ansprüche 1 bis 9, umfassend die folgenden Schritte: a) Versetzen eines oder mehrerer Styrolpolymeren (A) mit einem oder mehreren Treibmitteln (B) und, optional einem oder mehreren Keimbildnern oder Nukleierungsmitteln 14 10. A process for producing expandable, thermoplastic polymer particles according to any one of claims 1 to 9, comprising the following steps: a) mixing one or more styrene polymers (A) with one or more blowing agents (B) and, optionally, one or more nucleating agents or nucleating agents 14
(C), und optional einen oder mehrere Zusatzstoffe (Z) in einer Menge, die die Domänenbildung und daraus resultierende Schaumstoffstruktur nicht beeinträchtigt, so dass eine Polymermischung (I) entsteht; b) Vorexpandieren der Polymermischung (I). (C), and optionally one or more additives (Z) in an amount which does not impair the formation of domains and the resulting foam structure, so that a polymer mixture (I) is formed; b) pre-expanding the polymer mixture (I).
11 . Verfahren gemäß Anspruch 10, dadurch gekennzeichnet, dass mindestens Schritt b), bevorzugt Schritte a) und b) unter einem Druck stattfindet, der den Atmosphärendruck übersteigt. 11 . Process according to claim 10, characterized in that at least step b), preferably steps a) and b) takes place under a pressure exceeding atmospheric pressure.
12. Verfahren gemäß Anspruch 10 oder 11 , dadurch gekennzeichnet, dass die Prozessschritte a) und b) in einem Extruder mit anschließender Unterwassergranulation bei einem Druck im Bereich von 1 ,5 bis 11 bar stattfinden. 12. The method according to claim 10 or 11, characterized in that process steps a) and b) take place in an extruder with subsequent underwater granulation at a pressure in the range from 1.5 to 11 bar.
13. Verfahren gemäß Anspruch 10 oder 11 , dadurch gekennzeichnet, dass die Prozessschritte a) und b) in einem Autoklaven stattfinden. 13. The method according to claim 10 or 11, characterized in that the process steps a) and b) take place in an autoclave.
14. Verfahren gemäß einem der Ansprüche 11 bis 13, dadurch gekennzeichnet, dass die Prozessschritte a) und b) in einer Suspension stattfinden. 14. The method according to any one of claims 11 to 13, characterized in that the process steps a) and b) take place in a suspension.
15. Verwendung der expandierbaren, thermoplastischen Polymerpartikel gemäß einem der Ansprüche 1 bis 9 in einem Formteil, gebildet durch Verschweißen der expandierten thermoplastischen Polymerpartikel mittels Heißluft oder Wasserdampf, wobei das Formteil vorzugsweise eine spezifische Dichte von weniger als 250 g/L, bevorzugt von weniger als 150 g/L aufweist. 15. Use of the expandable, thermoplastic polymer particles according to any one of claims 1 to 9 in a molded part, formed by welding the expanded thermoplastic polymer particles by means of hot air or steam, the molded part preferably having a specific density of less than 250 g/L, preferably less than 150 g/L.
EP21801543.6A 2020-10-30 2021-10-28 Expandable, thermoplastic polymer particles based on styrene polymers and process for the preparation thereof Pending EP4237474A1 (en)

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WO2024008914A1 (en) 2022-07-08 2024-01-11 Ineos Styrolution Group Gmbh Expanded thermoplastic polymer particles with a content of recycled material, and method for producing same

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