Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-10-24
2003-02-25
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S259000, C526S264000, C526S336000, C526S340000
Reexamination Certificate
active
06525156
ABSTRACT:
The present invention relates to insoluble, styrene-containing popcorn polymers, processes for their preparation and the use of the popcorn polymers as adsorbents, ion exchangers, carrier materials and filter assistants.
The name popcorn polymers stands for foam-like, crusty polymer particles having a cauliflower-like structure. Owing to their generally strong crosslinking, popcorn polymers are as a rule insoluble and scarcely swellable.
DE 2 255 263 discloses a process for the preparation of insoluble, crosslinked and only slightly swellable polymers of N-vinylpyrrolidone, in which N-vinylpyrrolidone is polymerized in aqueous solution in the presence of, as a crosslinking agent, a cyclic acid amide which contains at least two ethylenically unsaturated groups. The polymerization reaction is initiated by heating the reaction solution to at least 80° C. and is completed at the boiling point of water.
U.S. Pat. No. 3,277,066 relates to a process for the preparation of insoluble polymers of N-vinyllactams by heating N-vinyllactams in water in the presence of alkali metal and alkaline earth metal oxides and hydroxides as a catalyst.
Houben-weyl, Volume 14, Makrom. Stoffe, Part 1, page 98 (1961) discloses that popcorn polymers are formed from mixtures of styrene with divinylbenzene. Such polymers are also formed in the industrial butadiene styrene polymerization. Methyl acrylate, too, tends to form popcorn polymers.
On contact with the monomers of which they are composed or with other monomers, popcorn polymers have the property of being able to convert said monomers into popcorn polymers. They act so to speak as a nucleus for the polymerization. However, the activity is lost if they come into contact with air.
Ullmanns Encyklopädie der Techn. Chemie, 4
th
Edition, Volume 19, page 385 (1980), discloses that an insoluble polymer slightly swellable in water is formed on heating N-vinylpyrrolidone with hydroxides and alcoholates of the alkali metals and alkaline earth metals in a spontaneous reaction. Such substances referred to as popcorn polymers are also formed on heating N-vinylpyrrolidone with divinyl compounds in the absence of oxygen.
EP-A-0 177 812 discloses a process for the preparation of insoluble, only slightly swellable polymer powders based on monoethylenically unsaturated carboxamides, carboxylic acids and carboxylic esters, in which an active popcorn polymer is used for initiating the polymerization, said popcorn polymer being obtainable by heating a mixture of from 99.6 to 98.8% by weight of N-vinylpyrrolidone and from 0.4 to 1.2% by weight of a compound having at least 2 ethylenically unsaturated double bonds to a temperature of from 100 to 150° C. in the absence of oxygen and polymerization initiators.
These popcorn polymers are used, for example, for absorbing tannins from beverages and as ion exchangers. Carboxyl-containing popcorn polymers can also be obtained by hydrolyzing polymers containing acrylate and acrylamide units.
U.S. Pat. No. 2,341,175 describes the popcorn polymerization of styrene with polyunsaturated organic esters (e.g. allyl acrylate). The spontaneous mass polymerization of styrene and comonomer is carried out at 80° C. and in reaction times of 6-7 days. The reaction product is worked up with benzene, isolated, dried and milled. Porous, insoluble and nonswelling styrene copolymers in powder form are obtained.
EP-A-0 088 964 describes a process for the preparation of popcorn polymers of basic vinyl heterocycles and up to 30% by weight of various comonomers. The initially taken initiator is a mixture of N-vinylpyrrolidone and divinylethylene urea. After the reaction has started, the water-soluble, basic vinyl heterocycle (e.g. N-vinylimidazole) is added together with comonomer and water. Styrene is also mentioned as a suitable comonomer.
It is an object of the present invention to provide an insoluble and only slightly swellable polymer which is chemically inert and surface-rich and can be prepared simply and in acceptable reaction times. Moreover, the polymer should be economical and should be capable of being prepared as far as possible in the absence of a solvent.
It is a further object of the present invention to provide novel substances which can be used as adsorbents, ion exchangers, carrier materials and filter assistants.
We have found that this object is achieved, according to the invention, by insoluble, only slightly swellable popcorn polymers containing
a) from 50 to 99% by weight of styrene and/or at least one monounsaturated styrene derivative;
b) from 0.1 to 40% by weight of at least one N-vinyllactam or N-vinylamine and
c) from 0.1 to 10% by weight of at least one difunctional crosslinking component,
the stated percentages by weight of the individual components a) to c) being based on the total amount of the popcorn polymer and summing to 100%.
Monounsaturated styrene derivatives are understood as meaning, inter alia, sulfo-containing styrenes, e.g. styrene-3-sulfonic acid or sodium styrene-3-sulfonate, and amino-containing styrenes. Amino-containing styrenes are to be understood as meaning, for example, styrenes which carry the following substituents in the 3 position: —CH
2
N
+
(CH
3
)
3
Cl—, —CH
2
N
+
(CH
3
)
2
CH
2
CH
2
OHCl—, —CH
2
N(CH
3
)
2
, —CH
2
NHCH
3
, or —CH
2
NH
2
. The abovementioned styrene derivatives are known, inter alia, as monomers for the preparation of ion exchange resins.
In the present invention, the monomers a) are used in amounts of from 50 to 99, preferably from 70 to 99, particularly preferably from 75 to 97, % by weight, based on the total amount of the popcorn polymer.
Hydrophilic components b) are generally understood as meaning N-vinyllactams or N-vinylamines. The following polymerizable comonomers may be mentioned as being preferred:
N-Vinyllactams and N-vinylamines, in particular N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylimidazole, N-vinyl-2-methylimidazole, N-vinyl-4-methylimidazole and N-vinylformamide.
Preferred hydrophilic components are N-vinylpyrrolidone, N-vinylimidazole and N-vinylcaprolactam, particularly preferably N-vinylpyrrolidone.
In the present invention, the monomers b) are used in amounts of from 0.1 to 40, preferably from 0.5 to 30, particularly preferably from 1 to 25, % by weight, based on the total amount of the popcorn polymer.
Monomers c) are generally understood as meaning compounds which contain at least 2 ethylenically unsaturated nonconjugated double bonds in the molecule and hence act as difunctional crosslinking agents in the polymerization. Preferred monomers c) are, for example, alkylenebisacrylamides, such as methylenebisacrylamide and N,N′-acryloylethylenediamine, N,N′-divinylethylene urea, N,N′-divinylpropylene urea, ethylidenebis-3-(N-vinylpyrrolidone), N,N′-divinyl-(2,2′)-diimidazoleylbutane and 1,1′-bis-(3,3′-vinylbenzimidazoleith-2-one)-1,4-butane. Further suitable crosslinking agents are, for example, alkylene glycol di(meth)acrylates, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, tetraethylene glycol acrylate, tetraethylene glycol dimethacrylate, diethylene glycol acrylate, diethylene glycol methacrylate, aromatic divinyl compounds such as divinylbenzene and divinyltoluene, and vinyl acrylate, allyl acrylate, allyl methacrylate, divinyldioxane, pentaerythrityl triallyl ether and mixtures of the crosslinking agents.
Particularly preferred crosslinking agents are N,N′-divinylethyleneurea and divinylbenzene.
The crosslinking agents are used in amounts of from 0.1 to 10, preferably from 0.1 to 8, particularly preferably from 0.2 to 5, % by weight, based on the total amount of the popcorn polymer.
Popcorn polymers containing
a) from 60 to 99% by weight of styrene,
b) from 0.5 to 30% by weight of at least one N-vinyllactam or N-vinylamine selected from the group consisting of N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylimidazole and methylated N-vinylimidazole and N-vinylformamide, and
c) from 0.1 to 8% by weight of at least one difuncti
Ernst Andreas
Meffert Helmut
Ruchatz Folker
Sanner Axel
Stein Stefan
BASF - Aktiengesellschaft
Keil & Weinkauf
Pezzuto Helen L.
LandOfFree
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