Preparation of polyacetals, use thereof and novel polyacetals

Details Preparation of polyacetals, use thereof and novel polyacetals Preparation of polyacetals, use thereof and novel polyacetals

1995-02-02

1996-04-09

Acquah, Samuel A.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From aldehyde or derivative thereof as reactant

528230, 528243, 528248, 528250, 525472, 524773, 524843, 252 32, 252 325, 25217423, C08G 400

Patent

active

055063322

DESCRIPTION:

BRIEF SUMMARY
RELATED APPLICATIONS

This application was filed as PCT International Application Number PCT/EP 93/02176 on Aug. 16, 1993.
The present invention relates to a process for preparing polyacetals by copolymerizing glyoxylic esters with other copolymerizable monomers in the presence of anionic or cationic polymerization initiators and optional hydrolysis of the copolymerized units of glyoxylic ester present in the copolymer, to the use of the copolymers thus obtainable as additive in detergents and cleaners, as water treatment agent, and as dispersant for finely divided substances, and to novel polyacetals.
EP-B-0 001 004 discloses polymeric acetalcarboxylates of the formula ##STR1## where Y is at least one comonomer which is present in the polymer in random distribution, polymers against degradation at an alkaline pH, having from 1 to 4 carbon atoms.
The poly(acetal-carboxylate)s are prepared by homopolymerization of glyoxylic esters or by copolymerization of glyoxylic esters with copolymerizable compounds, such as epoxides, aldehydes, carboxyl-containing compounds and mixtures thereof in the presence of cationic catalysts, such as boron trifluoride etherates, or anionic initiators, such as sodium methyl diethylmalonate. To stabilize the polyacetals thus obtainable against degradation at an alkaline pH, the ends of the polymer chains are tipped with chemically stable groups; for example, the substituents R.sup.1 and R.sup.2 in the formula I can each be alkyl, hydroxyalkyl or carboxymethyl. The poly(acetal-carboxylate)s of the formula I are used as builders in detergents and cleaners. The poly(acetal-carboxylate)s are biodegradable.
U.S. Pat. No. 4,169,934 discloses copolymers of the general formula ##STR2## where p is at least 1, n is at least 2, Y is at least one monomer from the group of the olefins and the aldehydes having from 1 to 3 carbon atoms, and M is as defined in the formula I.
According to Example 1 of the cited patent, dimethyl ketomalonate is dissolved in methylene chloride and copolymerized with formaldehyde at about 0.degree. C. using sodium diethyl methylmalonate as initiator. After the copolymerization trifluoroacetic acid and ethyl vinyl ether are added to the mixture and the ester groups of the copolymer are hydrolyzed with aqueous sodium hydroxide solution. The sodium salts of the copolymers thus obtainable are used as builders in detergents. The copolymers are stable under alkaline conditions, but depolymerize in an acid medium to form biodegradable fragments. In the process described in U.S. Pat. No. 4,169,934 the formaldehyde is introduced into the polymerizing mixture in gas form. The use of liquid formaldehyde as comonomer appears to be possible in principle, but is out of the question in industry because of the tendency of anhydrous formaldehyde to undergo explosive polymerization. According to the reaction scheme indicated in Houben-Weyl, Volume E30, Part 2, Georg Thieme Verlag, page 1393 (1987), anhydrous formaldehyde can be polymerized not only cationically but also anionically.
It is an object of the present invention to provide an improved process for preparing polyacetals by copolymerization of glyoxylic esters with formaldehyde and optionally with other copolymerizable monomers. It is a further object of the present invention to devise detergent additives, water treatment agents and dispersants for solid substances. It is yet a further object of the present invention to provide novel substances.
We have found that the first object is achieved by a process for preparing polyacetals by copolymerization of polymerization initiators, with or without the introduction of stable end groups and with or without hydrolysis of the copolymerized units of monomer (a) present in the copolymer, which comprises using as monomers (b) cyclic formals derived from diols, homopolymers of formaldehyde, trioxepane or mixtures thereof, although up to 50% by weight of this group of monomers (c) may be replaced by other customary copolymerizable monomers.
We have found that the second object is achieve

REFERENCES:
patent: 4169934 (1979-10-01), Papanu
Houben-Weyl, vol. E30, Part 2, Georg Thieme Verlag, p. 1393 (1987).

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