DE1128663B - Process for polymerizing monomeric unsaturated compounds - Google Patents

Description

The polymerization of unsaturated organic compounds with the aid of redox systems is known to be carried out quickly and at low temperatures. Redox systems are combinations understood from reducing and oxidizing compounds, as reducing compounds primarily tertiary amines, sulfinic acids and mercaptans or mercaptides may be mentioned. Of the the disadvantage familiar to those skilled in the art, associated with the use of tertiary amines as redox components is, consists in the discoloration of the polymers produced in this way, especially in the case of crystal clear Interferes with products. Sulphinic acids show considerable effectiveness in some cases, but they have the disadvantage that they are unstable and can only be stored for a limited time. Redox systems, whose reducing constituents are mercaptans or mercaptides then cause a rapid hardening of ethylenically unsaturated compounds if the mixture to be polymerized small amounts of a copper compound are added. This procedure is in the German Auslegeschriften D 13 947 IVb / 39c and D 15 904 IVb / 39b. Another increase in The rate of polymerization can be described in the German Auslegeschrift D 17 723 IVb / 39c Process by adding such a compound that has a loosely bound halogen atom contains, to be achieved to the monomer to be polymerized.

Those with polymerization accelerators, which are made from a per compound, a mercaptan or mercaptide, optionally a chlorine compound and a copper salt exist, achievable polymerization rates are so good that - there is too much hardening plastic compound must have a certain "processing latitude", d. H. not too quickly may harden - a further increase in this direction is generally no longer necessary. The known accelerator systems are not fully satisfactory in those cases in which the copper the polymer discolored or / and in which the need to polymerize by heating the mass to be hardened to 30 to 40 ° C "to bump" is inconvenient, as z. B. for processing of polyesters in connection with glass fiber mats using the hand lay-up method applies.

For the technical utilization it is crucial that the processor gets the simplest possible accelerator system in hand. B. from four Kompo processes for polymerizing
of monomeric unsaturated compounds

Applicant:

Röhm & Haas G. mb H.,
Darmstadt, Mainzer Str. 42

Dr. Gruber and Dr. Wohnhas, Darmstadt,
have been named as inventors

nenten (per compound, mercaptide, chlorine compound and copper salt) built-up redox system undoubtedly is not met -.

It has now been found that unsaturated compounds such as styrenes, vinyl esters and in particular Acrylic and methacrylic compounds, under the action of one of a per compound and one Mercaptide of thiocarboxylic acid esters or of thioglycol esters of the general formulas

- (CH ₂ ) " -

respectively

Me.

S- (CH ₂ V-COOR

S- (CH ₂ V-COOR

Me-S- (CH ₂ VO-CO-R

respectively

S- (CH ₂ VO-CO-R

Me "

S- (CH ₂ VO-CO-R

Harden the established redox system in a few minutes without additional heating. In the formulas mentioned, Me denotes a metal from group I or II of the Periodic Table, primarily cadmium or zinc, η denotes the number 1 to 4, and R denotes an alkyl, aryl or aralkyl radical.

209 577/446

Of the formulas shown. Mercaptide compounds the mercaptides of thioglycolic acid esters are of greater practical importance.

Even if the per compounds known as polymerization accelerators, such as benzoyl peroxide, Lauroyl peroxide, di-tert-butyl-di-perphthalate, cumene hydroperoxide, butyl hydroperoxide and the like, to carry out of the new process are useful, a combination of the thioglycolic acid derivatives mentioned has been found with mono-tert-butylpermaleate with regard to the rate of hardening and completeness the polymerization, d. H. with regard to the Avoidance of residual monomers remaining in the polymer has proven particularly advantageous. Except the advantages already mentioned, the new accelerator systems have a good shelf life, so that the components both on their own and either as a solution of the thio compound in the Monomers or in another liquid, e.g. B. in a plasticizer, or as a mixture of the per compound can be stored with a polymer for longer periods of time.

Mainly from - the processing technology of methacrylates is the hardening of one made of polymethyl methacrylate and monomeric methyl methacrylate existing mixture under the action of a Accelerator or an accelerator system, in particular from dental technology, known. The new The redox system is also excellently suited for hardening such masses. Furthermore, this is Procedure according to the invention for hardening casting resins based on polyester with excellent success usable. Crystal clear polymers, e.g. B. block polymers of methyl methacrylate based on the have been prepared according to the invention, experience neither in 4-way polymerization nor in the later weathering a discoloration and thus differ from those plastics that with The help of such rapid accelerators were produced, some of which were made from a copper compound or from consist of a tertiary amine.

In Example 1 below, the effectiveness of the new redox system (experiments 5 to 9) is with the known accelerator (experiments 1 to 4), the reducing component of which is also a mercaptide, compared.

The tests were carried out at room temperature (21 ° C). At this temperature the known mercaptides achieved no polymerization in the course of 8 hours. From the already mentioned Auslegeschrift D 15 904 IVb / 39b is known that a polymethyl methacrylate and methyl methacrylate

ίο (quantity ratio 1: 1 to 1: 0.1) existing mixture under the action of a peroxide, a copper salt and an alkali or alkaline earth mercaptide tertiary mercaptans hardened at a higher temperature (37.5 ° C) in 4 to 7 minutes.

The polymerization of methacrylic acid methyl ester described in Example 2 under the action of a According to the invention to be used redox system was in a second case with the addition of a copper salt carried out. It has been shown that copper in the new accelerator systems the polymerization does not promote, but inhibits.

Example 3 shows the production of a commercial polyester based on maleic acid. Ethylene glycol — styrene with various mercaptide and amounts of peroxide described.

example 1

3 g of polymethyl methacrylate and 1.5 g of methyl methacrylate were (about 21 C ⁰⁾ (, mercaptide and optionally Cu ⁺ + peroxide) was stirred with various redox systems together at room temperature and tested the accelerating effect by measuring the maximum polymerization temperature and the polymerization time associated.

In experiments 3 and 4 in the table below, dibenzoyl peroxide (15 mg) was used as the peroxide component and in all other experiments 15 mg of mono-tert.-butylpermaleate was used as the peroxide. Copper was in the indicated experiments at a concentration of 10 ~ ^{4%> au} f the monomer calculated as copper oleate used.

attempt
No. Mercaptide Cu ++ Maximum
temperature
° C Polymerization
duration 78 5 min. 10 sec. comment 1 Zn mercaptide of tert-dodecyl
mercaptan (19 mg) - no polymerization 70 6 min. 30 sec. Mercaptide insoluble 2 the same + the same 78.5 4 min. 15 sec. the same 3 the same - the same 76 3 min. 50 sec. the same 4th the same + the same 65 8 min. the same 5 Cd mercaptide of thioglycolic acid
2-ethylhexyl ester (20.6 mg) - hard polymer, clear,
colorless 6th Cd mercaptide of thioglycolic acid
butyl ester (19 mg) - the same 7th Zn mercaptide of thioglycolic acid
2-ethylhexyl ester (38 mg) - the same 8th Zn mercaptide of thioglycolic acid
2-ethylhexyl ester (76 mg) - the same 9 Isobutyric Acid Cd Mercaptide
/? - thio-ethyl ester - the same

Example 2

Methyl methacrylate was isothermally at 2O ⁰ C in sealed tubes under inert gas once with 0.24% mono-tert-butylpermaleinat and 0.33 ° / o Cadmiummercaptid of thioglycolic acid-2-ethylhexyl and the other with addition ΙΟ ^"40 / ,, Cu ⁺ + (as Cu oleate) polymerized. While the sample without the addition of copper was practically 100% polymerized after 3 hours, the sample with copper was only viscous after 20 hours. ">

Example 3

For curing a commercially available mixture of an unsaturated polyester and styrene were at 21 ° C (room temperature) mono-tert-butylpermaleate and cadmium mercaptide of thioglycolic acid 2-ethylhexyl ester added and the accelerator effect by determining the maximum polymerization temperature and the polymerization time are determined. The following list shows the course of the polymerization with different mercaptide and amounts of peroxide.

Claims (2)

PATENT CLAIMS: 1. A process for polymerizing monomeric, unsaturated compounds under the action of a redox system composed of a per compound and a reducing sulfur compound, characterized in that a mercaptide according to one of the following formulas is used as the reducing component Me-S- (CH ₂ V-COOR respectively S- (CH ₂ V-COOR S- (CH ₂ V-COOR or Me-S- (CH ₂ VO-CO-R respectively S- (CH ₂ VO-CO-R MeC ° / o mercaptide ° / o peroxide Maximum
temperature
⁰ C Polymerization
duration 1
1
1.5 ¹ U
1
1 72
100 23 min.
13 min.
polymerized
reads after
5 min. - (CH ₂ V - O - CO · R 30 in which Me is a metal of group I or II of the Periodic Table, primarily cadmium or zinc, η denotes the number 1 to 4 and R denotes an alkyl, aryl or aralkyl radical. 2. The method according to claim 1, characterized in that mono-tert-butylpermaleate is used as the per compound used. © 209 577/446 4.62