DE1669689C3 - Process for the production of foamed ethylene copolymers - Google Patents

Description

unsaturated acids containing 10 to 20 carbon atoms. The method is also suitable for

th. In particular, stearic acid, oleic acid, encasing objects with foam

Palmitic acid or resin acid in question. Plastic.

The oxides are suitable for the process. The process is of particular importance divalent metals, of which the oxides of Me- 5 manufacture finely divided foams too. These could be the second group of the periodic system oen z. B. by continuously squeezing the clubs have special meaning. In particular, self-foaming mixtures and dividing the mixture Barium and zinc oxide are suitable for the process. can be obtained before foaming. You get The oxides mentioned can foam one another in combination with the liquid propellant method or in combination with other oxides, io particles of matter with diameters between 3 and e.g. with aluminum, iron oxide, nickel, bismuth. 20mm, the density of which is over 15g / l, preferably cobalt, Silver and potassium oxide can be used. can be between 15 and 40 g / l. With fixed

Based on 100 parts of copolymers, foams of the same density are obtained Mixtures except thiuram di or tetrasulfides 0.2 300 to 600 g / l. Such foam particles can up to 2 parts, in particular 0.3 to 1 part, of a fat 15 e.g. as fillers for upholstery, insulation or as acid and 0.5 to 7 parts, especially 1 to 5 parts, soil loosening agent can be used. Inventions Metal oxide added. Dedicated plates and foils are used

For the production of foams with especially the heat and sound insulation.

The foams obtained by the process

called nucleating agents. Ao have a gel content of between 20 and 70 ⁰ O are suitable

e.g. finely powdered silicates, such as talc, which may be on. The insoluble

are understood most expediently in amounts of 1 to 3 parts by weight, for example by

cent, based on the copolymer, used dissolving the polymer in decahydronaphthalene

will. Temperatures of 140 ° C can be determined. Which he-

In addition to polymer, the mixtures can contain foams that have a thermal stability. or tetrasulfide, fatty acids and metal oxy- tate, which are 20 to 30 ° C above the thermal stability as well as blowing agents and other components, the quality of foams are only below such as fillers, dyes, flame retardants, anti-use of the copolymers were made, Statics, stabilizers, lubricants or other It was surprising that the invention Contains polymers. Other polymers can be foamed mixtures despite the high gel gez. B. polyethylene, polypropylene, polyisobutylene, stop squeezing through nozzles and foaming lasdie in amounts up to 40 percent by weight, based on sen. With similar foaming processes, at on the copolymer, the mixtures added to which, for example, ethylene polymers can be oxides are cross-linked, it is only possible to

The thermoplastic ethylene copolymers are foamed mixtures with a gel content that in the thermoplastic state with the blowing agent of 5 to 7 ° / c through a nozzle and mixed. It is advisable to work with foaming. With a higher gel content, such temperatures that 10 to 100 ⁰ C, in particular 30-day processing are no longer possible,
up to 90 ° C above the crystallite melting point of the The parts mentioned in the examples are Ge polymers. The mixtures are less than 40 parts by weight.
Pressures kept that above the propellant pressure

of the propellant are at the mixing temperature, Example 1
so that the propellants are always in the liquid state under the mixing conditions. Below 100 parts of a terpolymer of 82 parts of blowing agent pressure is the vapor pressure of the blowing agent, ethylene, 8 parts of acrylic acid and 10 parts of acrylic above the molten copolymer to form t-butyl ester will be with 2 parts of tetramethyl. After completion of the thiuram disulfide, 0.5 part of stearic acid and 3 parts of the mixing process, the mixtures are mixed ent-talc in a homogeneous state. Extruded in a twin screw. This means that the mixers will be brought into a zone where the pressure is 5 ° and mixed with 9 parts of i-butane with 60 parts of this mixture per hour. The drop in the blowing agent pressure during the mixing time in the extruder of the mixture is 4 min. It is best to relax the temperature in the nozzle 160 ° C. The homoMixtures in a mixture that is stable under normal conditions is passed through a slot nozzle with the upright zone. To make the mixture use dimensions 75 x 4.7 mm pressed. In this case, it is advantageous to use continuously working mixers to foam the mass into an endless foam band, the devices. Among these, in particular, a cross-section of 80 cm ² has been found. The density of the extruder (screw press) has proven itself. The whore foam is 25 g / l, the gel content 48% (the ions of the mixing device are to be selected so that the content is determined by dissolving the foam at 140 ° C. when it leaves the mixing room and entering tetrahydronaphthalene. The percentages in the relaxation zone a homogeneous mixture δο ben the content of insoluble components),
made of ethylene copolymer, additives and foaming The foam is heat-resistant up to 100 ° C. He has educated middle. The mixtures can also be used in e.g. B. as cold and heat insulation can be used discontinuously working devices, for example in.

Pressure vessels with agitator, manufactured A mixture extruded under the same conditions

will. According to the method of the invention, 65 research which does not contain any additives leads to

Foams of different shapes do not receive nozzles with the same opening to none

will. For example, you can create endless foam profiles, usable foam. If you reduce the nozzle

like sheets, blown film or pipes, after the cross-section to 30 X 4.7 mm, a foam

can be obtained which has a cross-section of 25 cm ² . . . _

and has a heat resistance of 74 ° C. This example J

Foam has a coarser cell structure. _{] 00} Part of a copolymer of 72 parts

T he 1 ⁿ 5 ^{volumes of} > ^{5 parts of} acrylic acid t-butyl ester and 17 parts

^p "Acrylic acid is mixed with 3 parts of dipentamethylene

100 parts of a copolymer of 78 parts of thiuram tetrasulfide and 3 parts of dry talc, ethylene and 22 parts of t-butyl acrylate are mixed. This mixture is dry-mixed in an extruder with 1.8 parts of dimethyldiphenylthiuram disulfide and ^a throughput of 15 parts per hour of plastic-2 parts of talc. 18 parts of this i. ™ ™ ^{rt and '3} Τ ^"Ιβη a Kohlenwasserstoffgemi mixture are mixed per hour in a Einschicken-" ches from 60 · /. I-butane and 40 ° / o η-butane, extruder is plasticized with 3 TeUen Tetrafluordi- ^D. ! ^e homogeneous mixture is mixed aschloräthan a Folienb. the residence time in the extruder loading ^ use relaxed. the result is a closed cell carries 3 minutes, the temperature in the nozzle of the foam sheet D.chte 65 g / l at a thickness of 165 ° C . 15 ^{1) 2 mm}

Example 4 is extruded through a round nozzle of 4 mm
Diameter and parts the intumescent

Strand by means of a hot die, so 100 parts of an ethylene copolymer that

particles with a diameter of 13 mm contain 12 parts of vinyl acetate in polymerized form

obtain. ao with 1.5 parts of tetraethylthiuram disulfide, 2 parts

The foam particles have a gelchali of zinc oxide and 0.5 parts of azodicarbonamide as

40% and a thermal stability of 90 ° C. Nucleating agent mixed dry. The mixture will

With foam from the copolymer without crosslinking with the addition of 15 parts of isopentane per 100 parts

only the thermal stability of polymer in a single-screw extruder with pre-

75 ° C obtained. An attempt, plasticized by adding 1 part as a switched discharge extruder and in

Benzoyl peroxide to improve thermal stability, extruded in the form of a round profile. The received

Depending on the temperature control of the extruder, the foam strand has a gel content of 25%. Of the

neither to no noticeable crosslinking the copo-strand has a foam strand, which consists only of the

lymerisate or for sudden complete cross-linking copolymer was obtained, a double

tion and thus standstill of the work process. 30 diameters and a fine-cell structure.

Claims (1)

* Copolymers of are suitable for the process Claim ethylene with vinyl esters and / or esters of un- ^P saturated acids copolymerizable with ethylene, Process for the production of foams which contain at least ^ 60 percent by weight * ^ ¹ J ^ by mixing thermoplastic Äthylenco- 5 polymerized. Suitable comonomers smd polymers in the thermoplastic state with z. B. vinyl esters of acids with 2 to 5 carbon atoms blowing agents at pressures "which are above the blowing agents or esters of unsaturated acids von'Alkoholen with 1 partial pressures at the mixing temperatures and up to 20 carbon atoms. Advantageous Efnschaf.,, Have relaxation homogeneous mixtures, data foams from copolymers. "^ *% '">, in that Copo- "acetate or ^ a ™ ^ ™ ** ^ *** * lymerisate of ethylene and Vinylcstern or processing is carried tV Athylencop esters unsaturated / acids in the presence of the esters mentioned 1 thiuramdi or tetrasulfides with propellant respective unsaturated ^ mixes and relaxes the mixture. tonic acid, fumaric acid and maleic acid, ⁵ 15 sated included. So are z. B., in particular for Production of soft foams, copolymers of ethylene containing 5 to 20% acrylic acid and 5 to 20 »/» Acrylic acid t-butyl ester included in polymerized form. Suitable propellants for the Äthylencopolymensate com- * o men hydrocarbons, halogenated hydrocarbons and chlorofluorocarbon compounds in question, deGegenstand of the invention is a method for ren boiling points of 25 to 15O ⁰ C below the melting-producing foamed Athylencopolymc- point of the copolymers cherish. The melting point is understood here to mean the synthetic melting point Zur'Herstellung of foam-like Äthylenco- 15 are. Suitable propellants are ζ. Β aliphatic « various processes are known for polymers. or olefinic hydrocarbons with 3 bis, C-feei a process that is mainly related to the tech atoms, such as propane, butane, pentane or propene, nik introduced the copolymers in butene or pentene. Special remarks to J Tre.beiner continuous mixing device, medium have isobutane or hydrocarbons with 5 E. B. in an extruder, in the molten state 30 to 7 carbon atoms and at least two se.tenmit a liquid or gaseous propellant !, permanent methyl groups, their boiling points between e.g. an aliphatic hydrocarbon or - 10 and f6 <TC. Possible are ζ B. a fluorocarbon compound, mixed and the isopentane. Isohexane, 2 2-dimethylbutane. Of the obtained homogeneous gel pressed through a nozzle. Halogenated hydrocarbons are particularly suitable After leaving the nozzle, the gel foams among 35 such with 1 to 2 C atoms, such as methyl chloride, the vapor pressure of the propellant. For the her- ethyl chloride, dichloromethane. particularly soft foams are copo- Suitable chlorofluorocarbon compounds are lymerisate of ethylene with vinyls and / or dichlorodifluoromethane, fluorotnchloromethane, mono-acrylic acid esters used. Those using fluorochloromethane, U ^ -Tnfluortrichlorathan, and Foams obtained from such copolymers have 40 1,1,2,2-tetrafluorodichloroethane. a relatively low softening point, so that the amounts of propellants used Thermal stability is relatively low, which is when the mixtures of thermoplastic ethylene use the foam is often a hindrance as a cushion. copolymers and blowing agents 15 to i ^ ewicnts- It is also known that the percentage of heat of the blowing agent can be calculated based on 100 parts of Costand strength foam-like polymers through 45 polymer, contains. The amount of 1 abrasive Can increase crosslinking of the polymers. So it can be based on the desired space weight one z. B. foam-like polymers by incorporating foam-like ethylene copolymers and the th and decomposition of peroxides or by treatment pressure and temperature conditions during the Enhance yours with high-energy radiation. Post-processing. . Part of this, however, is that the crosslinked products 50 The Ethylencopolymensate are no longer thermoplastic in the presence, so that it is not possible from 0.5 to 7, preferably from 1 to 5 parts of thium, such crosslinked products after Konti- ramdi- and / or tetrasulphides, based on natural foaming processes, e.g. B. parts of copolymers, mixed with the blowing agent, to be processed into foams by means of an extruder. Particularly suitable to tetraalkyl or Dialkyld.a-There was therefore the problem, soft elastic 55 ryl-Thiuramdi- or -tetrasulfidverb.ndungen with Al-foams having relatively high thermal stability herzustel- kylgruppen, preferably 1 _len ent to 5 C-atoms keep. Mixtures of di- and te- It has now been found that foams can be used as trasulfides, which are particularly advantageous by mixing thermoplastic ethylene copolymers are Tetramethylthiuramclisulfid, Tetraathylthiuramsate in the thermoplastic state with blowing agents 60 disulphide, dipentamethylene thuramtelrasulphide and at pressures above the propellant pressure in the case of the dimethyldiphenylthiuram disulfide. Mixing temperatures are and relaxation of the foams with particularly advantageous E.gen- homogeneous mixture with particularly advantageous shafts, such as fine-grained cell structure and low Properties can be produced when copolyme density is obtained when the ethylene corisate is used from ethylene and vinyl esters or esters unpolymerized 65 together with thiurane di- or tetrasaturated Acids copolymerizable with ethylene in sulfides and fatty acids and oxides of bivalent ones Mixes presence of thiuram di or tetrasulfides with metals. Propellant mixes and the mixes relaxed. Of the fatty acids, the saturated and are suitable