Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1991-01-22
1993-07-20
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
5253299, 5253305, 525374, 525381, 525382, C08F 832
Patent
active
052294676
DESCRIPTION:
BRIEF SUMMARY
The invention relates to copolymers which contain amino groups and are soluble in organic solvents and which can be prepared by aminolysis from copolymers--prepared by means of free radical solution polymerization--containing alkyl ester groups, processes for their preparation and their use in coating agents.
The possibility of preparing copolymers containing amino groups by aminolysis of copolymers containing alkyl(meth)acrylate is already known from U.S. Pat. No. 4,120,839. In this process described there, copolymers are initially prepared by means of free radical polymerization from styrene and at least 35 mol % of alkyl (meth)acrylate, and are converted into the copolymers containing amino groups by heating, preferably in an inert solvent, in the presence of a catalyst, with aliphatic polyamines. These copolymers containing amino groups are employed together with epoxy resins in coating agents. However, the use of vinyl ester monomers in the preparation of the copolymers containing alkyl ester groups and the resulting problems during the polymerization are not described.
There are also no vinyl ester monomers co-used in the preparation in the case of the copolymers containing amino groups which are described in DE-PS 3,043,355, EP 40,288 and U.S. Pat. No. 3,634,372.
It is also known that copolymers containing amino groups can be prepared by using monomers containing amino groups in the polymerization (compare, for example, EP 165,580, EP 167,042 and EP 181,478), or by aminolysis of copolymers containing glycidyl groups (compare, for example, DE-OS 3,412,657).
It is moreover known that problems arise in the preparation of acrylate copolymers if monomers with a greatly different reactivity compared with acrylate monomers, such as, for example, vinyl esters of aliphatic monocarboxylic acids having 5 to 15 C atoms and branched in the .alpha.-position, are employed. In these cases, it is difficult to obtain uniform, that is to say randomly homogeneously distributed, copolymers.
One possibility of solving this problem is the process described in U.S. Pat. No. 4,039,734 for copolymerization of monomers of different reactivity, in which at least some of the reactive monomer is added continuously to the reaction mixture in an amount such that the relative monomer ratio remains constant. The amount of monomer required for this in each case is determined with the aid of the heat of reaction liberated.
In the process described in DE-PS 2,032,647, uniform vinyl ester, vinylaromatic and hydroxyacrylate copolymers are obtained by stepwise addition of the individual monomers. In this process, the total amount of vinyl esters is initially introduced together with 5 to 15% by weight of the total amount of the vinylaromatics and the total amount of the other monomers with functional hydroxyl groups and unsaturated carboxylic acids. The residual amount of monomer is then either added gradually in its entirety or is metered in so that the feed of OH and COOH monomers takes longer in time than the vinylaromatic feed. Disadvantages of this process are the very high residual monomer content (that is to say the amount of unreacted starting monomer, expressed in % by weight, based on the total amount of this monomer originally employed) of up to 40% by weight of vinyl esters if a high vinylaromatic content of up to 50% by weight is used, and the associated toxicity problems. The high solvent content of the coating agents caused by the high viscosity of the binder solutions is furthermore unfavorable in view of the pollution of the environment by solvent when the lacquer films are dried. There is also the risk of clouding phenomena in polymer solutions with a relatively high solids content, and these can only be eliminated by addition of further solvent.
The English-language technical information "VeoVa polymers LR-40 and LR-2041 for water-thinnable paints" from Shell also describes such copolymers containing vinyl esters, vinylaromatic and hydroxyalkyl esters, but these likewise have precisely the disadvantages mentioned above.
REFERENCES:
patent: 3669942 (1972-06-01), Van Westrenen
patent: 4120839 (1978-10-01), Emmons
patent: 4303563 (1981-12-01), Emmons
BASF Lacke+Farben Aktiengesellschaft[DE/DE
Sabourin Anne Gerry
Schofer Joseph L.
Werner Frank G.
Zitomer Fred
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