CH326175A

CH326175A - Process for processing polyvinyl chloride produced by the suspension polymerisation process to give filler-containing, warm-gelled plastic masses which are light-colored and light-stable

Info

Publication number: CH326175A
Authority: CH
Inventors: Max Dr Phil Schuler
Original assignee: Lonza Ag
Priority date: 1954-03-10
Filing date: 1954-03-10
Publication date: 1957-12-15

Description

  

  



   Verfahren zur Verarbeitung von nach dem Suspensionspolymerisationsverfahren hergestelltem Polyvinylehlorid zu füllstoffhaltigen, warmgelierten Kunststoffmassen, die   hellfarbig    und   lichtstabil    sind
Es   wurdefestgestellt,dass    bei der   Verar-      heitung    von Polyvinylchlorid mit Füllstoffen, wie z.

   B.   Kreiden,    Kieselweiss, Kaoline usw., gegebenenfalls in Gegenwart    von WN'eiehma-      chers    und Stabilisatoren, das Gel eine ver  schiedenartige Farbtönung aufweist,    je nach   lern Emulsionspolymerisate    oder Suspensionspolymerisate verwendet. werden, wobei unter   Suspensionspolymerisaten alle nach    dem Sus  pensionsverfahren polymerisierten    Produkte zu verstehen sind. So ergibt z. B. eine Masse, die ans Polyvinylchlorid in Form von Suspensionspolymerisat, Weichmacher, Kieselwei¯ als    Füllstoff sowie üblichen StabHisierungs-und    Gleitmitteln besteht, nachdem sie bei   160       gelatiniert wvnrde, eine Folie,    die eine dunkle SepiafÏrbung besitzt.

   Wird aber an Stelle des Suspensionspolymerisates ein Emulsionspolymerisat verwendet, so erhält man unt. er   denselben Beding2tngen    eine   elfenbeinfarbige    Folie, obwohl das Suspensionspolymerisat an sich   mindestens ebensogut thermostabil    ist wie das   Emulsionspolymerisat. Diese dunkle Fär-    bung, die bei der Verwendung von Suspensionspolymerisaten auftritt, kann sich in gewissen Fällen nachteilig auf das Material   aus-    wirken und schliesst damit die Verwendung von Suspensionspolymerisaten in gewissen Fällen aus.

   So z.   B.    können intensive Farbeffekte nur   durci      Einverleibezi anomal grosser    Mengen an Farbstoffen in die dunkle Masse erzielt werden, und es ist nicht, möglich, helle Pastellfarben zu erzielen. Weiter weist die dunkle Färbung eine schlechte Lichtechtheit auf, so dass nach Beleuchtung, z. B. durch Sonnenlicht, eine Bleichung eintritt.



   Wir haben nun gefunden, dass es durch Zugabe von die Verfärbung verhindernden Substanzen gelingt., nach dem Suspensionspolymerisationsverfahren hergestelltes   Poly-      vinylehlorid zu lichtstabilen, hellfarbigen,    in der Wärme gelierten Kunststoffmassen, die Füllstoffe und gegebenenfalls andere Zusätze, wie z. B. Stabilisatoren, Weichmacher usw. enthalten, zu verarbeiten. So hergestellte Massen, welche bei Temperaturen zwischen 140   und 170     C während Zeiten von  ber 5 Minuten   verarbeitetundgeliefertwurden,entspra-    eh. en in der Färbung denjenigen aus guten Emulsionspolymerisaten.



   Als die Verfärbung verhindernde Mittel können z. B. Hypophosphite, Hyposulfite, insbesondere die entsprechenden E-, Na-, Li-, Ca-, Ba-Salze, z. B.     Rongalit   (eingetragene    Marke), ferner Acetate, Thiosulfate, Stannate, Oxalate der Alkalien oder auch Verbindungen wie Dicyandia uisw. verwendet werden. Es genügen schon sehr geringe Mengen dieser Stoffe, z. B. eine Menge, die nicht mehr als   0,      5"/o,    auf das Polymerisat berechnet, aus



  



   Process for the processing of polyvinyl chloride produced by the suspension polymerization process into filler-containing, warm-gelled plastic masses which are light-colored and light-stable
It has been found that when processing polyvinyl chloride with fillers such as

   B. chalks, kieselweiss, kaolins, etc., optionally in the presence of WN'eiehmachers and stabilizers, the gel has a different color shade, depending on the learning emulsion polymers or suspension polymers used. , suspension polymers being understood to mean all products polymerized by the suspension process. So z. B. a mass that consists of polyvinyl chloride in the form of suspension polymer, plasticizer, silica white as a filler and customary stabilizing and lubricating agents after it has been gelatinized at 160, a film that has a dark sepia color.

   If, however, an emulsion polymer is used instead of the suspension polymer, an ivory-colored film is obtained under the same conditions, although the suspension polymer itself is at least as thermally stable as the emulsion polymer. This dark color, which occurs when suspension polymers are used, can in certain cases have an adverse effect on the material and thus excludes the use of suspension polymers in certain cases.

   So z. For example, intense color effects can only be achieved by incorporating abnormally large amounts of colorants into the dark mass, and it is not possible to achieve light pastel colors. The dark coloration also has poor light fastness, so that after lighting, e.g. B. by sunlight, a bleaching occurs.



   We have now found that by adding substances that prevent discoloration, it is possible to convert polyvinyl chloride produced by the suspension polymerization process into light-stable, light-colored, heat-gelled plastic compounds, the fillers and, if necessary, other additives, such as e.g. B. stabilizers, plasticizers, etc. contain to process. Compositions produced in this way, which were processed and delivered at temperatures between 140 and 170 C for times of more than 5 minutes, corresponded in color to those made from good emulsion polymers.



   As the discoloration preventing agent, e.g. B. hypophosphites, hyposulfites, especially the corresponding E, Na, Li, Ca, Ba salts, z. B. Rongalit (registered trademark), also acetates, thiosulfates, stannates, oxalates of alkalis or compounds such as dicyandia and the like. be used. Very small amounts of these substances are sufficient, e.g. B. an amount which is not more than 0.5 "/ o, calculated on the polymer

Claims

PATENT CLAIM Process for processing polyvinyl chloride produced by the suspension polymerization process into hot-gelled plastic compounds containing fillers, which are light-colored and light-stable, characterized by the addition of substances that prevent discoloration.

SUBCLAIMS 1. The method according to claim, characterized in that the method. Tanning preventing substances in an amount of less than 0.5 percent by weight, calculated on the polymer, are added.

2. The method according to claim, characterized in that the discoloration preventing substances are added in a menu of less than 0.1 percent by weight, calculated on the polymer.

3. The method according to claim, characterized in that inorganic salts are used as substances preventing discoloration.

4. The method according to claim and sub-claim 3, characterized in that hypophosphites are used as the discoloration-preventing snobs.

5. The method according to patent claim and dependent claim 3, characterized in that hyposulfites are used as substances preventing discoloration. makes or even an amount below 0.1%, zml to achieve the desired effect.

In certain cases it is also possible to create lighter shades by adding the usual organic thermal stabilizers, such as B. dibutyltin dimaleate to achieve. In this case, however, significantly larger amounts have to be added, which can amount to more than 4% calculated on the polymer and change the product in various ways due to the larger amount used.

example 100 parts by weight of a mixture consisting of 65 parts by weight of polyvinyl chloride suspension polymer, 35 parts by weight of dioctyl phthalate, 35 parts by weight of kieselweī, 4 parts by weight of lead carbonate, 9, 5 parts by weight of a lubricant, 0.07 parts by weight of sodium hypophosphite was added as the discoloration-preventing substance, whereupon the mass was added 165 C was processed and gelled in the mixing mill for 10 minutes. An ivory-colored, light-stable film was obtained. Measurements in the fadeometer showed no discoloration after 50 hours.

For comparison, the same mixture was processed in the same way with the omission of the sodium hypophosphite. Brown-colored films were obtained which, under the influence of light, rapidly a. lightened. If, on the other hand, an emulsion polymer is used in the latter mixture instead of the suspension polymer mentioned, then light-colored, light-stable films are obtained.