DE1180942B - Process for the production of polymer latices based on vinyl aromatic compounds - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C08f

German class: 39 c -25/01

Number: 1180 942

File number: J 20962IV d / 39 c

Filing date: December 5, 1961

Opening day: November 5, 1964

The invention relates to a process for the production of polymer latices based on of vinyl aromatic compounds, which is characterized in that a mixture of vinyl toluene, in particular an m- and p-vinyltoluene mixture, with one or more alkyl methacrylates, especially normal butyl or isobutyl methacrylate, in the presence of an alkyl mercaptan as a chain transfer agent in the emulsion polymerization is subjected.

The products of the process are for the production of easily dispersible pigment compositions valuable. The new copolymers contained in them have relatively little Molecular weight and are soluble in the petroleum fraction, which has an approximate boiling range of 150 to 200 ° C and is known commercially as "white spirit".

According to the invention, new copolymers of vinyl toluene and an alkyl methacrylate are obtained, which are solid at normal temperatures and easily soluble in white spirit.

The vinyl toluene employed in the process of the invention can be a pure isomer such as m- or p-vinyltoluene; the mixture of m- and p-vinyltoluenes, which is commercially available, is preferably used is available under the name "vinyltoluene" and usually about 65% of the m-isomer and contains 35% of the p-isomer. The vinyl toluene does not have to be completely free of homologues and for example may contain a small amount of styrene.

Examples of alkyl methacrylates which can be used in the process of the invention, are methyl, ethyl, propyl, amyl, nonyl and especially n- or isobutyl methacrylates and mixtures of such alkyl methacrylates.

Examples of chain transfer agents which can be used in the process of the invention, are alkyl mercaptans such as tert-amyl and tert-dodecyl mercaptans. The amount of chain transfer agent used depends on the amounts of vinyl toluene and alkyl methacrylate to be copolymerized away. If, for example, equal amounts by weight of vinyl toluene and butyl methacrylate are copolymerized, then in white spirit soluble solid copolymers using not less than 0.005 molar amounts of a mercaptan, calculated on the total number of moles of the monomers.

If vinyl toluene is copolymerized with less than the same amount by weight of butyl methacrylate Process for the production of polymer latices based on vinyl aromatic
links

Applicant:

Imperial Chemical Industries Limited, London

Representative:

Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr

and Dipl.-Ing. S. Staeger,

Patent Attorneys, Munich 5, Müllerstr. 31

Named as inventor:

Arnold Edwin Ambler,

Arthur Topham, Manchester, Lancashire

(Great Britain)

Claimed priority:
Great Britain 12 December 1960

(43 566),

dated November 15, 1961

larger amounts of mercaptan are needed to prevent the formation of higher polymers, which are found in white spirit are not soluble to prevent. For example, solid mixed polymers soluble in white spirit are made from a 70:30 mixture (by weight) of vinyl toluene and butyl methacrylate when using not less than 0.012 molar amounts of mercaptan and from an 80:20 mixture (weight) of these reactants using no less than 0.025 molar amounts of mercaptan based on each based on the total number of moles of monomers. The method of the invention can be carried out by adding a mixture of vinyl toluene, one or more alkyl methacrylates, and chain transfer agents a stirred aqueous solution containing an initiator, for example potassium persulfate, and a Dispersing agents, for example potassium stearate or Turkish red oil, can be carried out. Suitable Working temperatures are between 50 and 100 ° C, and the mixture can, for example, about Stir for 1 hour. In this way a latex of the copolymer is formed.

409 710/447

The copolymers of the invention can be isolated from the latex by flocculation (for example by the addition of hydrochloric acid), followed by filtration, washing and drying.

The products of the invention, which are solid at normal temperatures and soluble in white spirit, can e.g. B. by the method of Belgian patent 598 711 for the preparation of dispersible Pigment compositions are used. Latices with a particle size between 0.01 and 0.5 μ are particularly suitable.

Copolymers of vinyl toluene and butyl methacrylate are particularly valuable because they are made from monomers that are commercially available Are available, and because they have excellent results when used for the preparation of dispersible Provide pigment compositions by the method of Belgian patent 598,711.

In the following examples, parts are by weight.

example 1

A mixture of 25 parts of stearic acid, 350 parts of commercial vinyl toluene (with a content of 64.6% m-isomer and 35.4% p-isomer), 150 parts of n-butyl methacrylate and 1860 parts of water is stirred while 94 parts of 9.2% potassium carbonate solution, 5 parts of potassium persulfate and 21.1 parts of tert-dodecyl mercaptan are added. The air in the reaction vessel is replaced by nitrogen replaced and the temperature increased to 70 ° C. Then the temperature rises exothermally in the course from 12 minutes to 88 ° C. The temperature is then increased to 90 ° C. and the mixture for 30 minutes stirred for a long time at 90 to 95 ° C. The latex is cooled and passed through a 60 mesh screen for removal passed through by some coagulated polymers.

Instead of n-butyl methacrylate in this example, a stoichiometrically equivalent amount can be used Methyl, ethyl, propyl, amyl or nonyl methacrylate can be used.

Example 2

A mixture of 310 parts of water and 32 parts of 9.2% potassium carbonate solution is at 90 to 95 ° C stirred under nitrogen while a mixture of 5 parts of stearic acid, 78 parts of commercially available Vinyltoluene, 20 parts of n-butyl methacrylate and 4.25 parts of tert-dodecyl mercaptan at the same time a solution of 1 part of potassium persulfate in 50 parts of water is added over 30 minutes. The mixture is stirred for a further 30 minutes at 90 to 95 ° C. and the latex is cooled.

Instead of 4.25 parts of tert-dodecyl mercaptan in this example. 3.4 parts of tert-amyl mercaptan to be used.

Example 3

A mixture of 16.7 parts of stearic acid, 117 parts Commercially available vinyl toluene, 50 parts of isobutyl methacrylate and 590 parts of water are stirred, while 53.5 parts of 9.2% strength potassium carbonate solution, 1.67 parts of potassium persulfate and 7 parts of tert-dodecyl mercaptan can be added. The air in the reaction vessel is replaced by nitrogen and the Temperature increased to 70 ° C. The temperature rises exothermically to 86.5 ° C in the course of 13 minutes, the mixture is then heated to 90 ° C and held at 90 to 95 ° C for 30 minutes. To to cool, pass the latex through a 60 mesh screen to add some coagulated polymer remove. The particle diameter is 0.07 μ.

Example 4

A mixture of 27 parts of stearic acid, 1713 parts of water, 378 parts of commercial vinyl toluene, 162 parts of n-butyl methacrylate and 23 parts of tert-dodecyl mercaptan is stirred at 50 ° C. while 314 parts of 1.5 η-ammonia are added, whereupon 5.4 parts of 30% strength hydrogen peroxide in 60 parts Follow water. The temperature is increased to 90 ° C. over the course of one hour. After 1 hour Stirring at 90 to 95 ° C., the latex is cooled. The particle diameter is 0.07 μ.

Each of the latices described in the above examples can be prepared by adding dilute hydrochloric acid flocculated and the polymers can then be isolated by filtration, washing and drying. Solid polymers are obtained which are easily soluble in white spirit.

Claims (1)

Claim: Process for the production of polymer latices based on vinyl aromatic compounds, characterized in that a mixture of vinyl toluene, in particular a m- and p-vinyl toluene mixture, with a or more alkyl methacrylates, in particular normal butyl or isobutyl methacrylate, in Subjected to the presence of an alkyl mercaptan as a chain transfer agent of emulsion polymerization will. Considered publications:
German Patent No. 958,251;
German Auslegeschriften Nos. 1018 621, 1066 744; Fr. Krczil, "Kurzes Handbuch der Polymerisierungstechnik", Vol. II: Mehrstoffpolymerisierung, 1941, S. 142. 409 710/447 10.64 & Bundesdruckerei Berlin