DE1504357A1 - Foams made from thermoplastic resins with a firm, non-porous skin - Google Patents

Description

(US 261 683 - prio 28.2.63 case D-4 - 2656) RAVBS Industry J

Wilmington. Del./V.St.A " Hamburg, January 20, 1964

Foams made from thermoplastic resins with a firm, non-porous skin.

The present invention relates to the manufacture of Containers made of expanded polystyrene or other thermoplastic resins.

It has already been suggested, for example in the United States patent 3 042 972, expanded polystyrene and other thermoplastic resins by vacuum forming, see below To process cups or other containers. In general is however the © vacuum / orfοrmurg before Sohaumfolien because of the porous structure of the material with difficulty tied together.

Ea is also known to be an expandable sheet made of thermoplastic To cool resin as it exits the extruder, Subject of the above-mentioned USA patent specification and according to the USA patent specification 3 011 217 this cooling takes place before any substantial expansion or expansion takes place. the

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Vacuum deformation of this HrUrIaIa is connected with difficulties, because there are some problems when I am shocked three directions auadennt.

It is also known from US Pat. Nos. 2 905 972 and 2 945 261 to foam a thermoplastic resin as it exits the extruder, where it can expand until it comes into contact with the surface of a die that limits the foaming. The foam produced in this way has a low density of, for example, less than 0.096 g / onr. It is also clear from these patents that previous attempts to produce foamed thermoplastic resins by direct extrusion have only led to unsatisfactory results, namely when such resins are exfcruded into the air above their foaming temperature, they foam into uneven, wavy structures. In addition, the products obtained according to these patents are already in their final form and can no longer be processed into other forms. Sin similar procedure is also used in the USA Pa fc er? 2 857 625.

The object of the present invention is therefore to form a non-porous, solid skin on foamed thermoplastic resins such as polystyrene, and thus a To produce foam material, the surface of which has greater mechanical stability during further processing

₅ ORIGINAL BATHROOM

having. Ö0961 7/064 β ~ ³ ~

A further purpose of the present invention is the production of τοη cups or anceren containers from polystyrene foam to ff or other accentuated £ cj "r. Back" table harscn, ai a smoother "seuhore \ ινΛ less? absorbing Otnrf3.üoho uv.ö cir. better auschcn zci £ ai: _u

Furthermore V:? Z; vcekr diu rrfindun *; uia Herötol'uurjg von vakuunverforatci ?, aufi vr-Mlumten thermcpIa: M. ^; · Raw Uavzen without unhighnesses or! Dformierunaen oowic; <: \ v. Hcro'-ollung from ncha "iin ;; t3rf1mh: icn;: u: j ihermcpiastiBOhca H .rx.sr v / i β" boiapiclswoiess I'olytt. "Tv) I, the öiirch vacuum.;. '·' Formation to BehSItern v ^ lt ^ rvcra ^ boitot «onion can-

The "Toitarcn Zwncko and Aul would be *? as well as äio Acwondbarkait der rr 'icperötn £ r''"inaurt£; result from the following Beaaliroib ^ r: _t \ vvelnhe Joriooli only preferred Av.rrrführungun ^ sbeispiolc Ί.ν ,,. · 1Γ: * ΐ ;. au; Viilreicho / btlnderunger in ICünnen of through · ΐυιί ^1ϋ Γ ^{^:.:} ιβη i u: haanno & liegon.

It \ vur1i «now aei ^ Anflon, that the mentioned purposes have been achieved,. -Cx'atr know, v-cnn πε-.η u: f the Schcuubahn Fue therino plaatio.ihem I'urr. in the Au. ^ 'riit aue the Pxtrucor eir.e solid hair, forms. Γ.ϊε · 3 weM 'iaaui'c-h ercials that the Olieril- ·. ? he .. 'ßar Tuhv beiii exit from iom extruder quickly ai- ". ^ -.-, oV; i? ^ ecOch rlen main part of the web with to cool, 30c-iij; Hc £ 2t aiob wiiit-ar to einea Foam can expand.

9098 17/06 49

The invention is explained below with reference to the drawings explained in more detail · mean therein!

Figure 1 - a section through the foam extruderf

Figure 2 - a perspective view of the foam web as it exits the extruder)

Figure 3 - a βchematisoh shown section through a vacuum mold for a mug;

Figure 4 - along a schematically illustrated section the line 4-4 in Figure 2;

FIG. 5 - a schematic representation of a cooling device;

FIG. 6 - a section along the line 6-6 in FIG. 2;

FIG. 7 - a vertical step through a book made according to the invention;

FIG. 8 - a section along the line 7-7 in FIG.

For the charging of the extruder shown in Figure 1, a granulate of 50 parts of impact-resistant polystyrene ("Tuflex 216", a bit 5 £ polybutadiene-modified polystyrene from Foster Grant) and 50 parts of regular crystal polystyrene ("Dylene 8" from Koppers) was used is denoted by "Hiachung A ^N " below.

90 parts of mixture A were mixed with 10 parts of foamable polyetyrene granules containing 6 ^ pentane ( ^M Dow Feiespan 101 · »), and 0.5 part of white oil based on an aliphatic

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Erdölkolilenwasaerstoffee ("Bayol 35") dry mixed at room temperature. 0.3 part of powdered, anhydrous citric acid and 0.4 part of powdered sodium bicarbonate were then added and the mixture was circulated after 15-20 minutes. The resulting mixture 3 was placed in the feed device 4 of a conventional plastic extruder 6, in which the temperature is 107C ©, ι The plastic mixture then passed through the extruder _{cylinder S 1} where it was softened and kneaded by means of a screw 10. The temperature in the cylinder was 163-177 ⁰ C and the pressure measured at the Auetrittsende, 176 kg / cm; the nozzle adapter there was a temperature of 171 ⁰ C. Then came the plastic into the nozzle 14 and was extradiert through a pinch-off or gap opening 16 to a polystyrene foam web 10th The web has a temperature of about 149 ^° C. when it exits the extruder. The web begins to expand or swell about 1.25 cm behind the extruder and takes place in all three dimensions. When exiting the gap 16, the web has a thickness of 0.88 mm. Within a Abstandee of 2 _f 5 cm from the gap opening 16, the top surface 20 of the web cooled 18 quickly by spraying with an air / Waaser mixture 24 of a Druckmiaoher 26 through nozzles 27, while the bottom side 22 of the web 1S simultaneously rapidly by spraying is cooled with an air / Waasergemisoh 28 from a pressure mixer 30 via nozzles 32 (see Figure 4) · According to another embodiment: »? form

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Air and water can also be sprayed from different Duaan, or it can be worked without water as shown in FIG. Instead of air, other gases such as nitrogen, argon, carbon dioxide, helium etc. can also be used. The air was treated with tree temperature (21 ⁰ C) and a speed of 15 m / AEC sprayed. The temperature and speed of the air and / or water cooling are not of decisive importance. An essential feature of the invention, however, is that the surface of the polystyrene (or another thermoplastic resin) is rapidly cooled below its yield point, so that none are on the surface Form bubbles while a sufficient amount of heat remains inside the web for good foaming. The temperature and speed of the coolant are adjusted so that just one skin, ie about 3-15 # at the top and about 3-15 $ at the bottom of the web, is cooled while the remainder of the main part of the web is not cooled and can continue to foam. If the cooling is too strong, the web does not foam at all. Anyone skilled in the art will be able to adjust the cooling so that it is neither too low nor too strong. In the particular case at hand, after cooling, the web expanded to a total thickness of 2.25 mm.

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The upper skin 20 and fli "lower skin 22 rcaron yes 0.125 mm thick, and the core 25 is about 2 _f 0 mm.

The cooling created an obero and. a lower skin which was largely smooth and free of blisters and which gave the containers made of this material a good appearance and good epilation effect. The products, such as cups, were less absorbent than the products made from known polystyrene foam sheets.

The 'KLLbehandlVaHt also avoids unevenness and seferniation of the polystyrene foam balm and a smoother, cleaner surface curse is obtained, which during the restoration: a great deal of damage. andskreft showed. As a result, use various ois Talm leichcor au. The aufge3Chäuir.te _r a Obore and a lower skinned web had a density of 0.40 g / cm.

The present Erfirdun ^ is bosonders for the preparation ▼ on Schauiasto ff high density tracks v / ie, for example, 0.29 to 0.72 g / cm ^ and preferably O _(? C 2 to _f 56 g / cm ^ suitable.

The web emerging from the extruder must be at least 0.125 mm thick and generally has a thickness from 0.62 Ms 1.12 nrni = rde foamed sheet is common

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1.50 to 3.00 mm and preferably 2.12 to 2.25 mm thick, but can now also have a thickness of up to 7 * 5. the Skin is generally 0.125 to 0.25 mm thick each. There the outer skins are largely unfoamed, they have a much higher density than the foamed core; their density can be, for example, 0.96 to 1.06 g / cm- * «

The temperature in the extruder can be varied in a known manner; it is preferably between 132 and 1 * f 10 ^° C., for example, but temperatures of up to 232 ^° C. can also be used. Dsr pressure in the extruder "is the nozzle adapter is generally 70-280 kg / cm and the D _r piece in the extruder with the use of polystyrene about 35 bie 105 kg / cm In the present specific example." The pressure was in the nozzle 70 kg / cm ² and the pressure in the cylinder 176 kg / osr.

The Sch & .jJB web 1-8 was, as shown schematically in Figure 3, heated to flexibility and then over a vacuum mold 42, where they deeply in a beaker ~ pulled and then cooled «, Die Vakuumfori! consists of a positive part or stamp 46 and eiue.v negative form 48? which are provided with vacuum lines 50 is. Vacuum drawing can be done according to any known method ^ n such as, for example, according to US Pat. No. 3,045,867, the extruded polystyrene rolls made from a

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foamed core uM upper one tlurobgehsnSiän and lower skin "is" can Similarly FTeioc as regul & ros ungeschEumtes polystyrene are deformed during the thermoforming dio s ßroiacMchtig © ^web;...? sucked i a beaker through öa vslrcl asiohen Au-j, the thickness of web verrißgert, eB ,, _2,.., 12 Isis 2 "29 to 0.62" to 1.0 dot in dor Mitt ο dos Ε © more α "Dieso thickness may vary between 0.25 and 1,25EHa where toi dis container still remain for hoißo Gctrünko and at the same time are not su νοίυκίίΐϋα.

The cup 44 consists of a uniform, uniform material, that is to say, of sinor 'viiag Üussorsn skin 52, elnsm aufeaishfiujaten grain 54 and gir.; R :. ^v ungescliäuiaten inner skin 56 "- Bsi öor 7al: uimvorformu: ^*: * u is the Yerfeliltnia the individual ScMclitöicsteen auein" other not changed significantly, "It is understood that the individual * Steep of B ^ crisrs different StG ??: euagozogen. be. So l: mm dta [Dieüra under öeiu edge 58 up to 1.5 mn batragen, while the middle part of the operator O., - ^r '0 to 1.0 mm diele, his kamu "öer BsenarhodurL iai: in general.- also thicker than the aittlere parts Tj ^ v edge can be known in v / oi * j · ;, gotiljioaelt, rolled οΛ &? a \ x £ differently W * 5iss formed wine.

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! times the present process cups with a thickness of only 0.25 mm or between 1.0 and 1.5 mm had such a good insulating effect, dad even with it boiling water, coffee, tea or chocolate could still be held comfortably in the hand. In contrast, the well-known cups for hot drinks have made Low density foams have a thickness of 2.0 mm or more. The cups according to the invention can accordingly be used in Vending machines or anywhere else that require less space than the well-known foam cups are stacked.

To produce the foam mass, a Propellant used as it is in the German patent. ... ... (registration H 50 333 IVa / 39b). The disclosure of this German patent specification is thereby included in its entire scope.

A mixture of 50-95 # non-foaming polystyrene, for example regular polystyrene, can be used as the starting material and / or high-impact polystyrene, and 5-50 # expandable Polystyrene can be used. If a propellant is used, it will be used in amounts from 0.02 to 10 pounds, and preferably from 0.4 to 2 $, based on the weight of the total Polystyrene used.

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■ In general, blowing agents can be used ,, consist of the reagieronden zvisi tmter form carbon dioxide and water ¹ Kiteinander components "T * he two components are usually employed in approximately equivalent amounts. How-to biatanzen as kohlendioxydentwiclcelnfie i3u "Aijinonium ~ <alkali and Erdalkaliearbciittte or bicarbonates ago applies, for example, Acanoniuia-Mcarbonat, ^ Has imabicarbonat, sodium _t KJaliumcarbci-at odor CalcitiKcarbonat. Di 'other co-nfonente consists of einoj?' Ingenious and 'igev / eise foaten acid or an acidic rcasiorende. SaIa of a strength, üt & sufficient to release the I? olilo: x3 /; xyd aurs c'am car "bor-at or bici-rbonate. In ßllgoniGJiinn errrhUIt the acid at least 3 »O milliiSqui" vii.-le: '. Te ηνό. Vorsst ^ tweisc niii3d «8i; ena 1O _f ')? .FilliUt; uivTil (.mtii ^ üurev ^ &. Pfiriitc ^ &. Pfiriitc ^ &. Pfiriitc ^ f Gi-sa ·., The acid kti.in organise!;. Or ciier · Ληοΐ ·.,: »Π? -3θ1ιβΓ liutar ε-ei : x. Goeiiinote sweet drinks are 2oraä> irc-. Primary as acid components

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! felfiir.ali'ai · ^, i ^ ^: - "* Kstsäure und '. ^ hthiilsüiire. A ns-i- ^. Xp eier iva ^ se-r-free ^' v.rcin or salts can also be fec-rU? i 'yciriÄ'io wx3 fceiapiolsv / eise OyelsilurodiLyörat or Cit "O ¹ -' neM ^ r-nonoh ^ Srat vorwonäet be ^.

Π coif ::. · -, "o K .'- ähKlt-tel for -mi-rmoplagtisobe Ha" «· © are vfi-vr-r "· m; vj .-. 'e selection, ües au varwertdender-, special

BATH ORIGINAL

The blowing agent depends primarily on the specific thermoplastic rare ββ to be incorporated into the lint. Inert liquids are preferred for all blowing agents, which have at most a low release capacity for the thermoplastic resin and which are volatile below the softening point of the resin. The resin, such as expandable polystyrene, generally contains 1 to 15 weight percent, and preferably 4.5 to 9 weight percent, of the volatile liquid. The boiling point of the liquid is preferably below 10O ⁰ C. Typical examples of suitable blowing agents are aliphatl8Che hydrocarbons having a boiling point between 10 and 10O ⁰ G, and preferably between 30 and 90 ⁰ C, z * B. Petroleum ether (preferably containing pentane or hexane or a mixture thereof), pwntane, hexane, isopentane, heptane, cyolohexane, cyclopentane, pentadiene and neopentane. Suitable volatile liquids also include methanol, ethanol, Hethylftoetat, Xthylecetat, acetone, Methylfonrlat, ethyl formate, Diohloräthylen, isopropylchloride, propionaldehyde, diisopropylether, bichlorofluoromethane and a mixture of pentane with 5 ~ 30 £ "a lower halogenated hydrocarbon like methylene chloride"

A wetting agent or lubricant can also be added, although this is not absolutely necessary. White oil based, for example, is suitable for this

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of an aliphatic petroleum hydrocarbon ("Bayol 35"), kerosene with an average of 8 carbons. in molecule, alkylphenolylalkylene oxide adducts such as the t-ootylphenolethylene oxide adduct with 10 ethylene oxide groups in Melekttl ("Triton X-100") _for triualauryl sulfate and sodium dedecylbenzenesulfonate. The lubricant can be of a nonionogenic or anionic nature.

The foams produced have normally closed cells of uniform size, and generally have a cell diameter of from 0.01 to O _t 5 mm.

If polystyrene is used, any normal crystalline polystyrene or impact-resistant polystyrene or a mixture of 5 to 95 % normal crystalline polystyrene and otherwise impact-resistant polystyrene can be used. If a thermoplastic styrene polymer is used, it will normally contain more than 50% by weight and preferably at least 70% by weight of styrene in the polymer. Impact-resistant polystyrenes are often produced by polymerizing monomeric styrene in the presence of 2.5 to 10% by weight of rubber-like diene polymers or by polymerizing styrene in the presence of 2.5 to 10% by weight of a difunctional substance. Such impact-resistant styrenes are, for example, a terpolymer of 5 i> acrylonitrile, 5 l> butadiene and 90 l> styrene, a copolymer of 5 i> butadiene and

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«* 5 from £ 95 £ ohloraulfonlertem polyethylene and styrene copolymers» a mixture aue and 95 i> styrene, a polymer obtained by polymerization of styrene in the presence of 95 + 5 i polybutadiene product 97.5 * 3 * 2.5 polystyrene and polybutadiene , a mixture of 95 J * polystyrene and 5 pounds hydrogenated polybutadiene with an unsaturation content of 35.4 #, in the presence of 5 Jt hydrogenated polybutadiene with an unsaturated content of 4.5 pounds polyet xol, a coating of 95 % polystyrene and 5 £ polyisoprene and a Qopolymeres of 99.5 f of styrene and 0.5 Jl.Divinylbenssol.

Unless otherwise stated, all data relate to parts by weight or percentages by weight

The foamable thermoplastic resins that can be extruded according to the present invention include cellulose ethers and esters such as xthyloellulose, cellulose acetate, cellulose acetate butyrate, homopolymers and copolymers of monomeric compounds with a CH ₂ = C <^ - group such as olefins, 8 «B. Ethylene, propylene and isobutylene, vinyl halides, e.g. vinyl chloride, vinylidene chloride, vinyl esters of carboxylic acids, e.g. vinyl acetate, vinyl stearate and vinyl benzoate, vinyl ethers, e.g. vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether, unsaturated carboxylic acids and their derivatives, e.g. acrylic acid

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Methacrylic acid, methyl acrylate, ethyl aorylate, methyl methaerylate, aorylamide, acrylonitrile and methacrylonitrile, and copolymers of the above-mentioned vinylidene monomers with ρί, / 5- unsaturated polycarboxylic acids and their derivatives, eg, maleic anhydride, biethyl maleate, dibutyl maleate and uewa. A preferred group of materials with which optimal results are achieved are the solid, relatively less elastic thermoplastic resins such as the homopolymers (and copolymers of vinyl chloride »homopolymers) of vinylidene aromatic hydrocarbons and ring-shaped halogenated derivatives thereof, e.g. styrene, o-chlorostyrene, p-chlorostyrene, 2,5-dichlorostyrene, 2,4-dichlorostyrene, p-methyletyrene, p-ithylstyrene, t & -Methylstyrene »vinylnaphthylene and copolymers such vinylidene monoDiere with each other and rough; other vinylidene, in which the copolymers $ 70> contains nindestens of vinylidenaromatißchun Kohlenvvatip & rstoffee, ζ * B. a copolymer of 70 $ styrene vid 30 ^ acrylonitrile. The most preferred resins are, Ale ei ^ Uhnt, the thermoplastic styrene polymer with an average of 70 wt. Styrene in the polymer.

Further geoigne ^ e thermoplastic resins are the polycarbonates, ζ ■ B d & fc polymers aue bisphenol A and diphenyl carbonate, fUe lO.lj ^ uretliane, ζ, Vu aua toluene diisocyanate and

with a molecular weight of 2025,

(/.acron) and nylon (7., B. polymeres

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The invention is particularly useful in the manufacture of cups suitable, but other open containers such as bowls, dots and plates or others can also be used Foam articles such as face masks getting produced. They can be used as packaging be used for cheese, ice cream or other foods.

The articles are preferably made by vacuum drawing the thermoplastic foam tap, it can but * the blow molding process can also be used · However, the invention is of particular value for the vacuum deep-drawing process, as it otherwise occurs during vacuum deformation solves difficulties arising from porous webs,

As used herein, "three-layer, uniform material ¹ * means that the inner core is bonded directly to the outer skin without the use of an adhesive or other intermediate layer.

The three-layer web can after foaming the core be deformed directly under vacuum or it can be stored, for example, as a Holle and then on for the Vacuum deformation required temperature to be heated.

BATH ORIGINAL

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Claims (1)

(OS 261 683 - prio 28.2.63 HAVÄ » Industrie. J ° · '· ^ " ²⁶⁵⁶⁾ Wllmliyton. Ptl, A »St.A. Haaburg, January 20, 1964 Claims. 1. Container, especially suitable for liquids Secher, aue high density thermoplastic foam, characterized in that it consists of (1) a core (54) made of foamed resin high density, (2) a solid outer skin (52) made of non-porous resin and (3) consists of a solid inner skin (56) made of non-porous resin, the core (54) making up 50 to 94% of the total thickness of the skin and core and being uniformly connected to the outer and inner skin throughout. 2. Container according to claim 1, characterized in that the core of foamed styrene polymer with a density of 0.19 to 0.72 g / cDr * and the outer and inner skin made of non-foamed styrene polymer with a much greater density than that of the kernea 3 · Container according to claim 1, characterized in that it contains at least 70 # styrene in the styrene polymer and has continuous, seamless, smooth wall surfaces on it . 909817/06 * 9 bad orig; nal -2- 4 · A container according to claims 1-3 "characterized in that the ₉ 96 g / cm asked the core has a density of from 0.32 to ^3, and O is at least 70 £ of Oeeamtdicke and most of the wall Beeher 0.29 Ms 1 , 29 mi thick. Process for the production of a foam faucet made of thermoplastic resin, characterized in that a hot sheet of completely rigid thermoplastic resin is extruded with a thickness of 0.125 mm, the main surfaces of the sheet are cooled quickly, but only to the extent that they cannot expand and form an outer skin, while the still warm core can expand further, the cooling being set so that (1) a core made of resin foam, (2) a non-porous, smooth, solid outer resin skin on one side of the core and (3) a non-porous, smooth, solid resin skin on the other side of the core and the core between 50 and. 94 i ° the total thickness of skin and core, core and skin are continuously connected to one another and that the skin has a much greater density than the core. 6. The method naoh claim 9, characterized in that the balding by treating the surfaces with a Gas or liquid flow takes place, which is a bad original 909817/064 9 -3- 150A357 -ν Jl significantly below the softening point of the resin lying temperature has " Method according to claim 5-6, characterized in that that the foam sheet is then thermoformed into an object made of a foam core with a non-porous, smooth, solid, interior and outer resin surface is further processed. 909817/0649