DK156627B - METHOD FOR MANUFACTURING VULCANIZED RUBBER HOSE - Google Patents

Abstract

1. A method of producing vulcanized rubber tubes, the unvulcanized roungh tubes being sheathed with a melted strengh-imparting thermoplastic, the melting point of which is above the vulcanization temperature of the rubber and which has an adequate tensile strength, whereupon the tubes are vulcanized, after which the sheathing is removed and at least partially re-used, characterised in that the plastic used for the sheathing is polyvinylidene fluoride (PVDF), the melting point of which is below the decomposition temperature of the rubber and which is insensitive to repeated shear stress.

Description

DK 156627 BDK 156627 B

Den foreliggende opfindelse angâr en fremgangsmâde til fremstilling af vulkaniserede gummislanger, idet de uvulkaniserede râslanger forsynes med en kappe af smeltet, styrkegîvende termoplastisk plast, hvis smeltepunkt ligger over gummiens vulkaniseringstemperatur, og 5 som har en tilstrækkelig hoj trækstyrke, hvorefter slangerne vulkaniseres, og kappen derefter fjemes og i hvert fald delvis genanvendes.The present invention relates to a process for the production of vulcanized rubber hoses, the unvulcanised tubing being provided with a sheath of molten, strength-giving thermoplastic plastic, the melting point of which is above the vulcanization temperature of the rubber, and having a sufficiently high tensile strength, then the hoses are then vulcanized. is removed and at least partially recycled.

En sâdan fremgangsmâde kendes fra tysk offentliggorelsesskrift nr.Such a method is known from German publication no.

27 15 493. Ved denne fremgangsmâde fores den uvulkaniserede 10 gummislange forst gennem et kolebad, hvor der samtidig pàfores et glidemiddel pâ gummislangens ydre overflade. Derefter fores den sâledes forbehandlede gummislange gennem en ekstruder, idet slangen sà bliver forsynet med en polysulfonkappe. Den med kappe forsynede slange afkoles derefter igen og fores til et vulkaniseringskammer.27 15 493. In this method, the unvulcanized 10 rubber hose is first passed through a bath, where at the same time a lubricant is applied to the outer surface of the rubber hose. Then, the thus-pretreated rubber hose is passed through an extruder, the hose then being provided with a polysulfone sheath. The sheathed tube is then cooled again and fed to a vulcanization chamber.

15 Efter vulkaniseringen afkoles den med kappe forsynede slange hurtigt i en væske, hvorefter kappen fjernes.After the vulcanization, the sheathed tubing is rapidly cooled down in a liquid, after which the sheath is removed.

En ulempe ved denne fremgangsmâde er, at det pâ grund af, at polysulfon har en smeltetemperatur pâ ca. 345eC, hvilket er langt over gummis nedbrydningstemperatur, er nodvendigt at nedkole den 20 uvulkaniserede gummislange for omslutningen med en kappe. Ogsâ efter omslutningen med polysulfonen er nedkoling uundværligt, for at gummislangen ikke skal blive beskadiget. Derudover er det en særlig ulempe, at hojst 25% af den anvendte polysulfon igen kan tilfores ekstruderen, da polysulfonkappens materialeegenskaber ellers 25 forringes sâ stærkt, at den bliver uegnet til anvendelse ved fremgangsmâden. Desuden skal polysulfonen, der er kendt som et hygroskopisk stof, for ekstruderingen terre i ca. 4 timer ved 135°C.A disadvantage of this method is that due to the polysulfone having a melting temperature of approx. 345 ° C, which is well above the decomposition temperature of the rubber, it is necessary to cool down the 20 unvulcanized rubber tube for the casing with a sheath. Also, after enclosing with the polysulfone, cooling down is indispensable so that the rubber hose will not be damaged. In addition, it is a particular disadvantage that a maximum of 25% of the polysulfone used can again be applied to the extruder, since otherwise the material properties of the polysulfone jacket are so severely impaired as to be unsuitable for use in the process. In addition, for the extrusion, the polysulfone, known as a hygroscopic substance, must be ground for approx. 4 hours at 135 ° C.

Aile disse punkter gor hele fremgangsmâden okonomisk uinteressant.All these points make the whole process economically unattractive.

Der kendes ogsâ en anden fremgangsmâde, ved hvilken der til omslut-30 ning af uvulkaniserede râslanger med en kappe anvendes bly. Ved denne fremgangsmâde bliver blyet opvarmet til smeltetemperatur og derefter afkolet sâ meget, at det fâr en dejagtig konsistens. I denne tilstand bliver blyet pâfort râslangen ved hjælp af en blypresse eller en blyekstruder. Ved denne fremgangsmâde bliver det pâforte bly 35 efter afsluttet vulkanisering afskrællet fra gummislangen ogAnother method is known in which lead is used for enclosing unvulcanized tube tubes with a sheath. In this process, the lead is heated to melting temperature and then cooled so much that it becomes a doughy consistency. In this state, the lead is applied to the tube by means of a lead press or lead extruder. In this method, the lead 35, after completion of the vulcanization, is peeled from the rubber tube and

DK 156627 BDK 156627 B

2 derefter genanvendt ved fremgangsmâden. Ved den kendte fremgangsmâde til omslutning med bly bortfalder de ved omslutningen med polysulfon nadvendige kaleforanstaltninger. Desuden. kan blyet ved denne fremgangsmâde anvendes flere gange.2 then recycled by the method. In the known method of lead enclosure, the necessary calibration measures required by the enclosure with polysulfone lapse. Moreover. the lead in this method can be used several times.

5 Ved smeltningen af blyet optræder der imidlertid sundhedsfarlige blydampe. Endvidere bliver der ved denne fremgangsmâde taie om store energiomkostninger til smeltning af blyet. Efter opvikling af den med en blykappe forsynede uvulkaniserede râslange pâ vulkaniseringstrom-len er den pà grund af den af blyet betingede sterre vægt vanskelig 10 at hândter'e.5 However, when the lead is melted, hazardous lead vapors occur. Furthermore, this method gives rise to high energy costs for melting the lead. After winding the unvulcanized tube of non-vulcanized tubing on the vulcanization drum, it is difficult to handle due to the lead-weighted sterile weight.

Der har lange været et behov for at tilvejebringe en kappepâfarings-fremgangsmâde, som muliggar en simplere hândtering, som er billigere, og som er mindre belastende for mennesker og milja.There has long been a need to provide a coat-dressing method that allows for simpler handling, which is less expensive and less burdensome for humans and the environment.

Bestræbelser pâ at tilvejebringe en sâdan fremgangsmâde har imidler-15 tid indtil nu været uden résultat. Ogsâ den ovenfor nævnte fremgangsmâde til kappepâfaring med polysulfon udgar en betydelig bêlastning af miljaet, idet der ved hver anvendelse af fremgangsmâden udskilles ca. 75% af den anvendte polysulfon som spildprodukt.Efforts to provide such a method, however, have so far been without results. Also, the above-mentioned polysulfone coating process involves a considerable load on the environment, with each application of the method separating approx. 75% of the polysulfone used as a waste product.

Opfindelsen har derfor til formâl at forbedre en fremgangsmâde af den 20 ovenfor nævnte art pâ en sâdan mâde, at der sikres en billig og simpel hândtering, og der alligevel kun sker minimal bêlas tning af miljaet.The invention therefore aims to improve a method of the above-mentioned kind in such a way as to ensure cheap and simple handling, and yet only minimal exposure to the environment is achieved.

Det nævnte formâl opnâs ifalge opfindelsen ved, at der som plast til kappen anvendes polyvinylidenfluorid, hvis smeltepunkt ligger under 25 nedbrydningstemperaturen for gummien, og som er ufalsomt over for gentagne forskydningspâvirkninger.The above object is achieved according to the invention in that polyvinylidene fluoride is used as plastic for the casing, the melting point of which is below the degradation temperature of the rubber and which is unsuitable for repeated shear effects.

Nærværende fremgangsmâde er simpel, billig og i henseende til milj avenlighed væsentligt forbedret i forhold til den kendte teknik. Polyvinylidenfluoridet kan efter afskrælning fra den færdigvulkani-30 serede gummislange og efter pàfalgende granulering genanvendes ved fremgangsmâden. Det er ikke navendigt hverken at nedkale gummislangen far kappepâfaringen eller at forsyne den med et glidemiddel.The present process is simple, inexpensive and substantially improved with respect to the prior art in relation to the prior art. The polyvinylidene fluoride can be reused by the process after peeling from the pre-vulcanized rubber hose and after subsequent granulation. It is not necessary neither to downsize the rubber hose to the coat application nor to provide it with a lubricant.

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Nedkoling efter pâforing af kappen falder ligeledes væk, da pâ den ene aide smelfcepunktet for den delfluorerede plast ligger under gummiens nedbrydningstemperatur, og da plasten pâ den anden side allerede lige under sit smeltepunkt udviser tilstraekkeMig hoj 5 trækstyrke. Polyvinylidenfluorid er overraskende ndk meget ufolsomt over for de gentagne forskydningspâvirkninger, som det udsættes for som granulat og derefter i ekstruderens plastificeringserihed.Cooling after application of the jacket also falls away, as at one aide the melting point of the partially fluorinated plastic is below the decomposition temperature of the rubber, and since the plastic, on the other hand, already under its melting point, exhibits very high tensile strength. Surprisingly, polyvinylidene fluoride is not very insensitive to the repetitive shear effects to which it is subjected as granules and then in the extruder's plasticity.

Plastens trækstyrke lider lige sâ lidt under det som under ind-diffunderingen af oploselige gummibestanddele under vulkaniseringen.The tensile strength of the plastic suffers just as much as it does during the diffusion of soluble rubber components during the vulcanization.

10 Heller ikke ved den forurening med afrevne gummipartikler, som ved afskrælningen af plasten kan blive hængende ved denne, sker der ved den fornyede tilberedning af plasten nogen væsentlig ændring af plastens trækstyrke.10 Nor does any significant change in the tensile strength of the plastics occur in the contamination with rubbed rubber particles which may become suspended in the peel of the plastic.

I det folgende vil en udforelsesform for fremgangsmâden ifolge opfin-15 delsen blive nærmere forklaret under henvisning til tegningen, hvis figur 1 skematisk viser en del af fremgangsmâdeforlobet.In the following, an embodiment of the method according to the invention will be explained in more detail with reference to the drawing, in which Figure 1 schematically shows part of the process.

Som det fremgâr af tegningen, bliver en uvulkaniseret ràslange 1 afviklet fra en forrâdstromle 3 ved hjælp af en afvikleindretning 2. Ràslangen 1 lober sâ geimem en ekstruder 4, der kan være opbygget i 20 hovedsagen pâ samme mâde som en i forbindelse med pâfering af en blykappe anvendt blyekstruder. Nâr ràslangen 1 fores ud af plast-ekstruderen 4, pâfores ràslangen polyvinylidenfluorid (PVDF) med en temperatur pâ ca. 210°C bg med en lagtykkelse pâ 0,5-0,6 mm.As can be seen from the drawing, an unvulcanized tube hose 1 is wound from a supply drum 3 by means of a unwinding device 2. The tube hose 1 thus runs a space extruder 4 which may be constructed in the same manner as one in connection with application of a lead sheath used lead extruder. When the tube hose 1 is fed out of the plastic extruder 4, the tube hose polyvinylidene fluoride (PVDF) is applied at a temperature of approx. 210 ° C both with a layer thickness of 0.5-0.6 mm.

Under pâforingen af PVDF understottes ràslangen indvendigt af en 25 kerne eller af trykluft. Kort efter at hâve forladt plastekstruderen 4 stivner PVDF'et og giver rorslangen 1 en tilstrækkelig stor styrke til, at slangen ved hjælp af en fremforingsindretning 5 kan transportées i retning af en pâ en opviklingsindretning 6 aribragt vulkanise-ringstromle 7 og opvikles pà denne.During the application of PVDF, the pipe hose is supported internally by a core or compressed air. Shortly after leaving the plastic extruder 4, the PVDF solidifies and provides the tube hose 1 of sufficient strength that the hose can be transported by means of a feeding device 5 in the direction of a vulcanization drum 7 arranged on a winding device 6.

30 Afstanden mellem plastekstruderen 4 og opviklingsindretningen 6 væl-ges under hensyntagen til fremforingshastigheden sâledes, at tempera-turen for plastkappen stadig er tilstrækkelig hoj Çstorre end 30°C) til at sikre den for opviklingsprocessen nodvendige formbarhed.The distance between the plastic extruder 4 and the winding device 6 is chosen taking into account the feed rate so that the temperature of the plastic sheath is still sufficiently higher than 30 ° C) to ensure the ductility required for the winding process.

Claims (1)

DK 156627 B Nâr vulkaniseringstromlen 7 er blevet helt beviklet med den med kappe forsynede slange, tages tromlen, efter at slangen er blevet over-skâret, ned fra opviklingsindretningen 6, hvorefter den med kappe forsynede slange vulkaniseres pâ en mâde, der er kendt og derfor Ikke 5 vil blive nærmere omtalt. Vulkaniseringstemperaturen ligger pà ca. 150eC, ved hvilken temperatur det til kappen anvendte PVDF stadig har en tilstrakkelig hoj trækstyrke til at kunne stôtte den af indvendigt tryk pâvirkede slange 1. Efter vulkaniseringen afvikles slangen 1 fra vulkaniseringstromlen 7, 10 medens plastkappen samtidig afskrælles fra slangen. Den afskrallede plast kan efter at vare blevet granuleret og - hvis vulkaniseringen har fundet sted under indvirkning af vanddamp - torret igen tilferes til anvendelse ved fremgangsmâden. Polyvinylidenfluorid er en kendt plast, der eksempelvis forhandles af 15 firmaet Dynamit Nobel under navnet Dyflor 2000. Fremgangsmâde til fremstilling af vulkaniserede gummislanger, idet de uvulkaniserede râslanger forsynes med en kappe af en smeltet, styrkegivende termoplastisk plast, hvis smeltepurikt ligger over 20 gummiens vulkaniseringstemperatur, og som har en tilstrakkelig hej trakstyrke, hvorefter slangen vulkaniseres, og kappen derefter fjernes og i hvert fald delvis genanvendes, kendetegnet ved, at der som plast til kappen anvendes polyvinylidenfluorid, hvis smeltepunkt ligger under gummiens 25 nedbrydningstemperatur, og som er ufelsomt over for gentagne forskydningspâvirkninger.DK 156627 B When the vulcanization drum 7 has been completely wound with the sheathed tube, the drum, after the hose has been cut, is taken down from the winding device 6, after which the sheathed tube is vulcanized in a manner known and therefore No 5 will be discussed further. The vulcanization temperature is approx. 150 ° C, at which temperature the PVDF used for the sheath still has a sufficiently high tensile strength to support the internally pressurized hose 1. After the vulcanization, the hose 1 is unwound from the vulcanization drum 7, 10 while the plastic sheath is simultaneously peeled from the hose. The peeled plastic can, after being granulated, and - if the vulcanization has taken place under the influence of water vapor - the dry again be applied for use in the process. Polyvinylidene fluoride is a known plastic marketed, for example, by the company Dynamit Nobel under the name Dyflor 2000. Process for the production of vulcanized rubber hoses, the unvulcanised raw tubes being provided with a sheath of a molten, strength-giving thermoplastic plastic whose melt purity can exceed 20 gum of rubber. and having a sufficiently high tensile strength, after which the tubing is vulcanized and the casing is then removed and at least partially reused, characterized in that polyvinylidene fluoride is used as a plastic for the casing, the melting point of which is below the decomposition temperature of the rubber and which is insensitive to repetitive forskydningspâvirkninger.