DETAILED DESCRIPTION OF THE INVENTION The novel vinylidene chloride polymer latices of the present invention can be prepared by free radical initiated emulsion polymerization processes well known to those skilled in the art.
Suitable emulsifiers which can be employed, either singly or in combination, in the preparation of the present latices include anionic emulsifying agents, such as alkyl aryl sulfonates, alkyl sulfates, alkyl sulfonates, and the like, as well as non-ionic emulsifying agents, such as polyoxyethylene-monofatty acid esters, sorbitan-monofatty acid esters, and the like.
Suitable free radical initiating catalysts which can be used include peroxides, such as hydrogen peroxide, tertiary butyl hydroperoxide, and the like; persulfates, such as potassium persulfate, ammonium persulfate, and the like; and redox systems such as an alkali metal bisulfite in combination with a peroxide or persulfate.
In the present invention, if the vinylidene chloride content of the polymer exceeds about 95 parts by weight, the crystallization speed, the film-forming temperature, and heat-sealing temperature will be undesirably increased and, at the same time, the shelf life of the latices is shortened to such an extent that the resultant coated materials cannot be put to practical use.
Furthermore, if the vinylidene chloride content goes below about 50 parts by weight, the highly advantageous barrier properties of vinylidene chloride polymers will be diminished.
As to propylene, if its content exceeds about 30 parts by weight, the polymerization productivity goes down to a practically unacceptable level due to very poor reactivity between the vinyl comonomers and vinylidene chloride.
On the other hand, if the propylene content is reduced below about 0.
5 part by weight, the improvement in the antiblocking and slip properties cannot be expected.
The comonomers which are copolymerizable with vinylidene chloride according to the present invention include the alkyl esters of acrylic and methacrylic acids such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, and the like; glycidyl esters of acrylic and methacrylic acids such as glycidyl methacrylate; nitriles of ethylenically unsaturated carboxylic acids such as acrylonitrile and methacrylonitrile; and vinyl monomers such as vinyl chloride and styrene
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Adhesives and Rubbers 
