Abstract: The nozzle plate of an ink jet print head is made of glass to provide a desirable wetting property for a stable meniscus of the ink column and the front surface of the plate is coated with a non-wetting material such as metal or plastic to prevent ink deposits at the front surface around the orifice. Any ink deposits at such front surface would adversely affect the ejection of ink droplets.

Abstract: Disclosed is a packaging material comprising a base layer of cellulose hydrate having on one surface a film coating which is impervious to water vapor, water and oxygen and which comprises a vinylidene chloride copolymer containing from about 90 to 92 percent by weight of vinylidene chloride, from about 5.5 to 7 percent by weight of acrylonitrile, from about 1.5 to 3.5 percent by weight of methyl methacrylate and from about 0.5 to 1.5 percent by weight of itaconic acid, said copolymer having a relative viscosity of about 1.04 measured at 23.degree. C. in a 0.1 percent strength by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and a relative viscosity of 2.8 measured at 23.degree. C. in a 3 percent by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and said film coating having a thickness corresponding to a weight per unit area in the range between about 3 and 10 g/m.sup.2.

Abstract: A mold having a desired print head shape includes a cover in which a plurality of rods or ductile fibers are attached, the cover being positioned with the rods extending into the mold and to the side opposite the cover. A hardenable synthetic material is introduced through a hole in the cover and after hardening of the material to form the print head, the rods are withdrawn from the mold to leave bores or apertures in the print head which serve as passageways for the droplets of ink.

Abstract: Improved PVC polymers are prepared by an emulsion polymerization process using an emulsifier mixture comprising:(a) 70-30% by weight of an alkyl sulfate of the formula R--OSO.sub.3 Me wherein R is alkyl of 10-18 carbon atoms and Me is Na or K; and(b) correspondingly 30-70% by weight of at least one member selected from the group consisting of(i) 0-65% by weight of an alkyl ether sulfate of the formula R--(OCH.sub.2 --CH.sub.2).sub.n --OSO.sub.3 Me wherein n is an integer of 1-5 inclusive and R and Me have the above-indicated values, and(ii) 0-60% by weight of a sodium alkyl sulfonate wherein the alkyl chain is of 10-20 carbon atoms.

Abstract: The rheological properties of plastisols of powdered polymerizates produced by polymerizing vinyl chloride or a mixture of vinyl chloride and a copolymerizable monomer in an aqueous emulsion in the presence of a water-soluble catalyst and an alkali salt of a fatty acid as the polymerization emulsifier and spray drying the resultant polymerizate, are improved by treating the powdered polymerizate with water in a weight ratio of from 1:2 to 1:15 and then drying.

Abstract: An improved process for the production of emulsifier-containing vinyl chloride polymers suitable for hard processing, the particle diameter of 90% of which is more than 63 .mu., by polymerization of vinyl chloride and optionally monomers copolymerizable therewith in an aqueous emulsion in the presence of water-soluble catalysts and alkali salts of carboxylic acids as emulsifiers at pH 9.5-11.5 and spray-drying the thus-obtained latex, is characterized by conducting the polymerization in a dispersion containing at least 45% by weight of monomers with sodium or potassium salts of fatty acids of 8-18 carbon atoms as emulsifiers to a conversion of at least 80%, and, during the spray-drying step, reducing the pH to 6.0-8.0.

Abstract: The necessity of opening a large polymerization reactor, in order to introduce a polymerization catalyst between charges in the batch suspension of polymerization of vinyl chloride on a commercial scale, is eliminated, thereby avoiding vinyl chloride emissions into the atmosphere, by isolating a segment of a charging conduit for a polymerization reactor containing vinyl chloride under pressure proximate the reactor; partially filling the isolated segment with water; charging the isolated segment above the water therein with a water-insoluble polymerization catalyst; and displacing into the reactor from the catalyst-charged segment first the water therein and then the catalyst therein with vinyl chloride under pressure.

Abstract: An improved process for the aqueous emulsion polymerization of vinyl chloride to be spray-dried and thus form paste-yielding polymers wherein the polymerization is conducted in an emulsion containing at least 45% by weight of monomers together with an emulsifying amount of alkali metal fatty acid salts of 8-18 carbon atoms at a pH of 9.5-11.5, and wherein the pH is reduced to a value between 6 and 7.5 prior to spray-drying or to a value between 4 and 7.5 during the spray-drying step.

Abstract: Vinyl chloride emissions from the gaseous phase of large scale vinyl chloride batch emulsion polymerizations are reduced by discharging the liquid phase only of the polymerizate to a discharge zone at a pressure differential of 0.1-2.5 atmospheres lower than the reactor provided by residual vinyl chloride in the reactor, maintaining the reactor unopened; and then conducting another vinyl chloride polymerization in the reactor in the presence of the residual vinyl chloride from the prior polymerization.

Abstract: A process for removing residual monomer from an emulsifier-containing aqueous dispersion of a solid vinyl chloride polymer having a surface tension of less than 60 dyne/cm., which comprises continuously admixing the polymer dispersion with steam in a fluid flow pipe under a pressure of 150-600 torr at a flow velocity of 1-20 m./sec., and passing said admixture at an exit velocity of 30-100 m./sec. horizontally into and along the walls of a degasification tank having a pressure 30-200 torr lower than the pressure in said flow pipe to evaporate residual monomer.

Abstract: Residual vinyl chloride contents of aqueous polyvinyl chloride dispersions is reduced to less than 50 ppm by withdrawing steam and vinyl chloride contained in a boiling aqueous polyvinyl chloride dispersion at a temperature of 80.degree.-100.degree. C. and at a vaporization rate per minute of 0.006-0.2 kg. steam per kg. of polyvinyl chloride for a period of time from 3-60 minutes until a vinyl chloride content of less than 50 p.p.m. is achieved.

Abstract: The method of preparing synthetic powders containing emulsifiers having good paste qualities by spray-drying polymer dispersions through a two-fluid atomizer having a spray ratio of about 1.6 to 5.0 kg. of spray air for each kg. of dispersion is improved. The polymer dipersions are prepared by emulsifying vinyl chloride monomer or a mixture of vinyl chloride monomer and unsaturated polymerizable compounds and polymerizing the monomers to produce polymers and copolymers of vinyl chloride. The improvement in paste qualities of the powders is achieved by introducing the spray dried powder into an air jet having a velocity from about 330 to 550 meters per second and having a weight ratio of gas to solids ranging from 1:10 to 5:1.