Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-07-29
2001-10-23
Wu, David W. (Department: 1713)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C558S031000, C558S034000, C526S911000
Reexamination Certificate
active
06307069
ABSTRACT:
TECHNICAL FIELD
This invention relates to a novel decomposition type reactive emulsifier comprising a compound having both a 1,3-dioxolane ring which is easily cleavable under acidic conditions and a copolymerizable unsaturated group and further to a polymer-modifying method comprising using said novel decomposition type-reactive emulsifier.
PRIOR ART
Heretofore known as emulsifiers for emulsion polymerization are anionic surfactants such as dodecylbenzenesulfonates, alkyl sulfates, alkyl sulfosuccinate salts, polyoxyalkylene alkyl(aryl) ether sulfates, etc., nonionic surfactants such as polyoxyalkylene alkyl(aryl) ethers, polyoxy-ethylene-polyoxypropylene block copolymer, etc., and soaps such as higher fatty acid soaps, rosin soap, etc., which are used either independently or in combination. However, the stability of the resulting polymer emulsions and the properties of the films and polymers obtainable from such emulsions are not always fully satisfactory but have much to be desired. Thus, the stability of emulsion polymerization, the suppression of foaming in the course of production, and the mechanical stability, chemical stability, freeze-thaw stability, pigment dispersibility and shelf-life of the resulting emulsion are not satisfactory and, in addition, when the emulsion is used for coating applications, the free emulsifier remains in the coating film so that the final coat is poor in water resistance, adhesion, heat resistance and weather resistance.
Furthermore, in the recovery of the polymer by destruction of the emulsion by salting-out, acid precipitation or other means, the residual emulsifier in the polymer causes deterioration of the physical properties, e.g. water resistance, heat resistance, weather resistance and strength, of the polymer. Therefore, a large quantity of washing water is required for thorough removal of the emulsifier from the polymer but since the emulsifier in the washings contaminates the river and other waters, a laborious procedure is required for removal of the emulsifier and treatment of the effluent.
To overcome the above problems, attempts have been made to reduce the amount of the emulsifier to be used for emulsion polymerization and/or reducing the level of addition of surfactants in other processing stages but none of such attempts has proved dramatically effective in solving the above-mentioned problems. The problems in respect of said stability of emulsion polymerization, stability of the emulsion obtained, and physical properties of the coating film and polymer, thus, remain yet to be solved.
In view of the above circumstances, a large number of reactive emulsifiers containing copolymerizable unsaturated groups have been proposed for overcoming the above-mentioned disadvantages of the conventional emulsifiers. For example, anionic reactive surfactants are described in JP-B-46012472, JP-A-54014431, JP-B-46034894, JP-B-54029657, JP-A-51030285, JP-B-49046291 and JP-A-56127697, among others, and nonionic reactive surfactants are described in JP-A-56028208 and JP-A-50098484, for instance, and using those surfactants, the polymerization of various monomers has been attempted.
However, when such a reactive emulsifier is used independently, the stability of emulsion polymerization is insufficient and the polymerization reaction dose not proceed smoothly in many cases unless it is used in combination with the conventional emulsifier. Moreover, the coating film obtainable from such an emulsion is not fully satisfactory in water resistance, adhesion, heat resistance and weather resistance.
Furthermore, reactive emulsifiers are used for reducing the effluent load in the recovery of the polymer by destroying the emulsion, but the conventional reactive emulsifiers are not satisfactory enough because, in the recovery of the polymer by salting-out or acid precipitation, the polymer cannot be completely precipitated in many cases, with the result that the polymer cannot be easily isolated and the polymer recovery rate is low. Moreover, since the conventional reactive emulsifier is not always well copolymerizable with monomers, the unreacted emulsifier finds its way into the waste water, resulting in a failure to achieve the objective reduction in effluent load.
As a measure for overcoming the above disadvantages, a technology according to a new principle, different from that underlying the reactive emulsifier, has been proposed. According to this technology, a decomposition type surfactant which can be easily decomposed by chemical treatment is used as an emulsifier for emulsion polymerization. For example, JP-A-03281602 discloses a method which comprises using a decomposition type surfactant which can be easily decomposed with an acid as an emulsifier for emulsion polymerization and recovering the polymer by acid precipitation which is procedurally easy. However, depending on the type of hydrophobic group and/or hydrophilic group contained in the emulsifier molecule, the decomposition product obtained by acid treatment is insoluble in water or adsorbed on the polymer so that a large quantity of water is required for washing the polymer. Moreover, the free decomposition product remaining in the polymer after washing adversely affects the physical properties of the polymer. Thus, the above-mentioned disadvantages still remain to be fully obviated.
Meanwhile, for the purpose of modifying a variety of polymers, various surfactants have heretofore been used to impart hydrophilicity, antistatic property, resistance to opacification, wettability, film-forming property and/or compatibility to the substrate polymers. The conventional surfactants, when they remain in the free form, cause aging , i.e. time-dependent degradation, of polymer properties and are not satisfactory, either, in the aspect of performance. Recently, to overcome those disadvantages, attempts have been made to use reactive emulsifiers as polymer-modifying agents but since the copolymerizability of the known emulsifiers with various monomers is not necessarily high, the problem of aging in polymer properties has not been sufficiently solved. Moreover, deterioration of the physical properties of polymers is a further disadvantage. Moreover, the reactive emulsifier essentially comprises both a hydrophobic moiety and a hydrophilic moiety but when the objective of its use is to impart hydrophilicity, for instance, the hydrophobic moiety is not always essential but rather detracts from the physical properties of polymers in many instances. Thus, the above-mentioned disadvantages have not been fully obviated.
OBJECT OF THE INVENTION
This invention, developed in the above state of the art, has for its object to provide a decomposition type-reactive emulsifier for emulsion polymerization which insures a high degree of stability of emulsion polymerization, marked improvements in the water resistance, adhesion, heat resistance and weather resistance of the coating film obtainable from the resulting emulsion, the ease with which the polymer emulsion can be destroyed, and marked improvements in the physical properties of the product polymer.
SUMMARY OF THE INVENTION
This invention has been developed with attention paid to he above disadvantages of the prior art.
DETAILED DESCRIPTION OF THE INVENTION
(1) History of the Invention
The inventors of this invention did much research and found that a compound having both a 1,3-dioxolane ring which is ready to undergo decomposition under acidic conditions and an allyl or methallyl group as a copolymerizable unsaturated group is suited as an emulsifier for emulsion polymerization.
(2) Summary of the Invention
Based of the above finding, this invention is essentially directed to a decomposition type reactive emulsifier of the following general formula (I) (hereinafter referred to as “the decomposition type reactive emulsifier of the invention” or briefly as “the emulsifier of the invention”).
wherein R
1
and R
2
may be the same or different and each represents an alkyl or alkenyl group of 1~20 carbon atoms or a hydrogen atom (provided, however, that both
Hashimoto Masayuki
Nishitani Toshiyuki
Dai-Ichi Kogyo Seiyaku Co. Ltd.
Egwim Kelechi
Jordan and Hamburg LLP
Wu David W.
LandOfFree
1,2 - Dioxolane decomposition reactive emulsifier and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with 1,2 - Dioxolane decomposition reactive emulsifier and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 1,2 - Dioxolane decomposition reactive emulsifier and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2589328